The criminalization of cannabis is one of the most mysterious and contested episodes in America’s war on drugs

The basic premise of the constructionist literature is that drugs have an identity beyond pharmacology. To a large extent, these two traditions ignore each other, and their mutual neglect limits our understanding of drugs as a problem: the idea of drugs refers at once to a social construct, a chemical substance, and a legal fiction . Although the current socio-legal literature mostly relies on the constructivist approach, I suggest that we also should not rule out individual experiences that shape the understanding of drugs. In this study, I define the drug problem as: various ways in which societies deal with drugs, i.e., define its meaning, produce competing discourses, establish forms of control and treatment, etc.; and various ways in which individuals experience and respond to drug control, i.e., resist social and institutional pressure, challenge the existing modes of control, mobilize for change, deal with stigma, shape alternative understandings of drugs, etc. The drug problem was on the radar of social scientists for many decades. In the 1960s, drug use became a politically contentious matter. Following the general resentment about drugs, scholarly literature contributed to the policy agenda by questioning the social and historical roots of drug regulation . Typically, scholars framed the drug problem through two perspectives—sociology of deviance and crime control studies . Sociology of deviance described drug regulation as a moral enterprise, and crime control studies—as an essential element of the war on crime. Both approaches complemented each other and provided macro-level, outcome-based explanations of the US’s history of drug regulation. Macro-level explanations—which still prevail in the sociological and socio-legal literature on drugs—are based on several theoretical propositions: the drug problem is socially and politically constructed; drug laws are a product of symbolic struggles that define the borderline between deserving and undeserving social groups; the stakes of the war on drugs are the accumulation of power and status by the elites; the public discourse on the drug problem is shaped by the mass media. Later, I discuss how these features are manifested in the “told” history of cannabis criminalization.

According to Emile Durkheim , normality and pathology are defined in relation to social context; that is,vertical rack what is normal for a particular society in a given historical period may be pathological in other circumstances. Throughout history, human beings have been using plants— e.g., tobacco, alcohol, poppy seeds, coffee beans, tea leaves, sugar cane, coca leaves, cocoa beans, or cannabis—to alleviate pain and distress. Some of those plants were socially constructed as dangerous, immoral, and deviant, and therefore fell under the state authorities’ control. Other plants, in contrast, were valued for their healing properties and potential to provide energy, alertness, or relaxation . In this section, I describe how cannabis from a legal healing herb became one of the most dangerous drugs in the course of the US’s twentieth century.In the scholarly literature, the history of drug regulation is often described as a moral enterprise directed against certain ethnic, racial, social, political, and other “non-American” groups. To understand how cannabis from a harmless intoxicant became a perilous drug, it is important to look at the cultural origins of cannabis legislation. According to Katherine Beckett, the association between drugs, crime, and racialized images of dangerous classes has characterized anti-drug campaigns throughout American history . The first anti-drug law restricting the use of opium was adopted in California in 1875 as a reaction to massive Chinese immigration and the fear of job competition . Similarly, the federal prohibition of opium in Canada at the beginning of the 20th century was a racialized project against Chinese immigrants . The first major campaign against cannabis started in the Southwest during the Great Depression when Mexicans were blamed for high unemployment rates . Until the 1910s, cannabis was a legitimate and innocent plant used for industrial, therapeutic, and recreational purposes. It had deep roots in Asian and European countries as a healing herb and a source of fiber. In the 1850s, cannabis became available in American pharmacies and was included in the 3rd edition of The Pharmacopeia of the United States as medicine helping with rheumatism, tetanus, epidemic cholera, hysteria, and mental depression.

Until the “reefer madness” era, the word “marijuana” was unknown in the US : pharmacists knew the plant by its botanic name cannabis sativa 15 , and recreational users referred to it as “hashish” or “Indian hemp.” There were no laws in Europe and Northern America regulating access to cannabis. Anti-alien sentiment in the United States grew in the mid-1880s as a response to social problems associated with mass migration . The Mexican Revolution caused thousands of immigrants to flee to the United States for safety and work. At the time, cannabis use was flourishing in Mexico, and Mexican laborers brought the plant into the US as a cheaper and more accessible substitute for alcohol and tobacco . Before Mexican immigration, Americans consumed cannabis mainly in chewable or liquid form, while Spanish speaking foreigners introduced a new form of consumption—smoking a mix of dried cannabis buds and tobacco.16 Like immigration, cannabis use was highly racialized: the main target of policymakers was not smoking, but smokers. The advent of the Depression made Mexican workers unwelcome and heightened anti-Mexican sentiment. The growing number of unemployed Mexicans were perceived as a welfare and crime problem, and jailing Mexicans on cannabis charges became part of the general attempt to reduce the labor surplus . The media and state officials popularized the term “marijuana”—a Spanish word used by farm workers—that tied the public perception of cannabis to “dangerous” Mexican migrants . Most Americans were not even aware that “Mexican marijuana” and “cannabis paste they get in the pharmacy” were essentially the same substance. The concern about Mexicans generated a new ideology about cannabis: since the Anglos perceived Mexicans as criminal types, cannabis also became associated with violence . African Americans were the second-largest group consuming cannabis . Both minorities were blamed for violent crimes committed against the white population, the worst of which was considered the seduction of white girls. By the 1930s, cannabis was gradually framed as an evil plant whose consumption damaged the brain and induced violent behavior. The image of cannabis as a “killer weed” justified the prohibition of cannabis at the state and federal level. According to Howard Becker, wherever rules are created and applied, we should expect to find people attempting to establish their code of right and wrong . The Federal Bureau of Narcotics , created in 1930, and its head Harry Anslinger played a pivotal role in criminalizing cannabis. Cannabis was not covered by the Harrison Act of 1914, which regulated the non-medical use of narcotics because pharmaceutical manufacturers confronted the criminalization of such a seemingly harmless drug .

Instead of adding cannabis to the Harrison Act, the FBN issued a special prohibitive taxing scheme—the Marijuana Tax Act of 1937—which established onerous licensing rules, imposed high excise taxes, and introduced harsh penalties to discourage cultivation, distribution, and consumption of cannabis. 18 From the mid-1930s until the early 1960s, the FBN shaped public beliefs about cannabis: it defined what was true about the drug and how it should be handled . Anslinger propagated myths about the criminogenic and psycho-pathological character of the plant. In particular, he claimed that continued use of cannabis produced mental disorders and physical deterioration, blamed doctors for intentionally overdosing patients, stymied all scientific studies on the plant, and repulsed any competing ideas that confirmed cannabis’s harmlessness . The impact of the La Guardia Report19 in 1944—which refuted that cannabis use results in insanity and criminal behavior—was limited because the FBN successfully restricted its distribution. The mass media and anti-cannabis propagandistic movies were at the service of Anslinger’s campaign giving cannabis bad publicity and sowing fears among the American public. Fabricated stories had a tremendous effect, and in 1941, cannabis was excluded from The Pharmacopeia of the United States. Doctors and pharmacists could not withstand Anslinger’s attack and defend their professional monopoly over drug testing, prescription, and distribution, and were ultimately forced to hand it over to state officials. Later, the American Medical Association and the American Pharmaceutical Association joined the crusade against cannabis. In 1951, the Boggs Act20 strengthened the Marijuana Tax Law. Louisiana Congressman Thomas Boggs,indoor hydroponic system who thought that drug laws were too lenient, sponsored a package of tough anti-drug laws establishing the same punishment for all narcotics. For the first time, cannabis and heroin were lumped together. Cannabis possessors could be sentenced to 2 to 5 years in prison for a first offense, 5 to 10 for a second offense, and 10 to 20 for subsequent offenses. Repeat drug offenders were denied parole considerations . In 1956, the passage of the Narcotics Control Act superseded the Boggs Act, and the minimum for a first offense increased to 5 years. The FBN gained tremendous power: by the end of the 1950s, it comprised 2% of the total law enforcement officers but was accountable for 17.6% of the federal prison population . According to Himmelstein , the role of the FBN in cannabis criminalization was more complicated than most authors suggest. The FBN became a dominant actor in shaping public beliefs and policies when states have already limited access to cannabis. In the early 1930s, the FBN was not interested in national cannabis control and was not aggressive or expansionistic. Although it is commonly thought that cannabis prohibition began with the Marihuana Tax Act of 1937, some US states took pre-emptive administrative measures to limit access to cannabis .

By 1937, most states had already passed anti-cannabis laws, and various senators and members of Congress had proposed federal anti-cannabis legislation. Drawing on an established image of cannabis as the “killer weed,” the FBN enhanced—rather than created—the cannabis problem . The “Mexican hypothesis” also requires further elaboration: to what extent are anti-Mexican sentiments responsible for cannabis criminalization? In his thorough analysis of the origins of cannabis prohibition in California, Dale Gieringer shows that cannabis prohibition resulted from bureaucratic initiatives prompted by the Progressive Era ideology. California was the first state that started the anti-cannabis campaign in 1913 by including cannabis in the Poison Act, which prohibited the sale and possession of certain substances except with a doctor’s prescription. At the time, the law did not receive any public coverage because recreational use of cannabis was largely unknown in California. Although the Poison Act’s passage coincides with the Mexican revolution and the mass migration of Mexican citizens to the US, the prejudices against ethnic minorities were not a significant factor in anti-cannabis policies in the 1910s. The connection between cannabis and Mexican communities appeared later when Mexican immigrants themselves were recognized as a“problem. 21” According to Gieringer, the forbiddence of cannabis was a logical extension of prohibitionist principles and the technocratic rationale of the Progressive Era bureaucrats. Even without Mexican immigration, the California government was well on its way to outlawing cannabis. Neither were Mexicans the main object of concern in the passage of the Marijuana Tax Act in 1937. As Himmelstein shows, cannabis’s association with Mexican laborers and other lower class groups influenced anti-cannabis legislation in less direct ways than it is often thought . When the FBN began talking about the federal regulation of cannabis, the image of youthful victims has replaced that of violent Mexican users in the public discussion. The concern was with what cannabis can potentially do to young people who can be seduced and ruined by the drug. In other words, by the end 1930s, the main goal was not to punish Mexicans but to save the youth. From the late 1950s, cannabis and its users were seen in new terms. The focus of cannabis policies shifted to new social groups that did not fit the definition of “good” citizenship—first to jazz players and poets, then to hippies and rock stars, and finally to social and political activists. Cannabis smoking increased among the white middle-class, including college students, and was no longer a chiefly Mexican and African American drug. The large-scale spread of cannabis use to middle-class youth led to a reevaluation of the drug’s dangers and to pressure for its decriminalization . As more young people experimented with cannabis, they came to realize that it did not turn them into miserable addicts but gave a gentle euphoria and relaxation.

Posted in hemp grow | Tagged , , | Comments Off on The criminalization of cannabis is one of the most mysterious and contested episodes in America’s war on drugs

Cannabis growers in Siskiyou’s subdivisions are especially vulnerable to detection

If nothing less than the county’s culture and agricultural order were considered at stake, it is no wonder that absolute, even prohibitionist, solutions emerged in Siskiyou, with the Sheriff’s Office having a central role in defending local culture.Siskiyou’s sparsely populated landscape has been home to illegalized cannabis cultivators at least since the late 1960s, largely in remote, forested, and public lands in the western part of the county. Medical cannabis’s decriminalization in 1996 inaugurated a modest expansion of cannabis gardens throughout the county . However, for the next 19 years, Siskiyou did not establish regulations for medical cannabis, in line with locally dominant ideologies of personal freedoms and property rights. Instead, the county relied on defac to management of cultivation by law enforcement and the court system’s strict interpretation of state law . In 2015, informed by public workshops held by the Siskiyou County Planning Division, supervisors passed the county’s first medical cannabis ordinance, which seemingly balanced concerns of medical cultivators and other county residents. Regulation would be overseen by the Planning Division, which placed conditions on cultivation , limited plant numbers to parcel size and would establish an administrative abatement and hearing process for complaints. The Planning Division, however, had been without code enforcement officers since 2008 budget cuts. Though the county authorized the hiring of one civil code officer in 2015, the Sheriff’s Office felt that the Planning Division “needed outside help” and moved to assist. Soon, the county’s limited abatement capacities were overwhelmed by vigorous enforcement and a wave of complainants. County supervisors, responding to the sheriff’s 2015 reports on the “proliferation” of cannabis gardens on private property, moved to heighten penalties for code violations, place numerous new restrictions on indoor growing and ban all outdoor growing . These strict county measures, which discarded and replaced publicly developed regulations, stoked reaction. When the Siskiyou County Board of Supervisors met in December 2015 to vote on these measures,rolling benches canada advocates and cultivators presented 1,500 signatures to forestall its passage, a super majority of attending residents indicated opposition, and supervisors had to curtail 3 hours of public comment to vote.

Despite this showing, supervisors passed the restrictive measures, prompting cannabis advocates to collect 4,000 signatures in 17 days to place the approved ordinances on the June 2016 ballot. Meanwhile, the Sheriff’s Office enforced the new stricter regulations .The Sheriff’s Office assumption of code enforcement blurred the line between noncompliance with civil codes and criminal acts. Stricter ordinances, still in effect in Siskiyou, created a broad, nearly universal category of “noncompliance.” No one we interviewed, including officials at the Planning Division and Sheriff’s Office, knew of a single cultivator officially in compliance. One interviewee estimated that growing 12 indoor plants would cost $40,000 in physical infrastructure, in addition to numerous licensing and inspections requirements, effectively prohibiting self-provisioning. The Sheriff’s Office notified the public that it would initiate criminal charges against “non-compliant” cultivators, specifically those suspected of cultivation for sale , child endangerment or suspected drug trafficking . Since the county regulations produced a situation where no one could comply, law enforcement could effectively criminally pursue any cultivator.Investigations were “complaint driven,” meaning not only that warrants could be issued in response to disgruntled neighbors upset about a barking dog on a cultivation site, as one person reported, but that police officers could serve as a kind of permanent, general complainant and take “proactive action” when they spotted code violations . Administrative warrants allowed deputies to enter properties with a lower evidentiary bar than they would have needed for criminal warrants, leading one patients rights group — Siskiyou Alternative Medicine — to file a lawsuit alleging county violations of Fourth Amendment protections against unreasonable search and seizure . In effect, cannabis’s criminal valences in the county endured through California’s shift of cannabis from criminal to civil provenance. Formerly illegal activities continued to be formally or informally treated as criminal matters, as researchers have noted with other stigmatized activities and groups, for example, after the decriminalization of sex workers in Mexico . Also, enforcement of civil matters can lead to substantive criminalization when those matters are stigmatized, as in the regulation of homelessness . While it is not unique for police officers to enforce civil codes, what is unique in Siskiyou County is the assumption of the entire civil process under the sheriff’s authority. To understand how this civil process became criminally inflected, in a county that voted for statewide cannabis legalization in 2016, one must first understand significant contextual shifts in who was growing cannabis where — and the challenge this posed to dominant ideas of land use, agriculture and culture.

Since 2014, cannabis gardens have emerged on many of the county’s undeveloped rural subdivisions in unincorporated areas of Siskiyou. Subdivided into over 1,000 lots each in the 1960s, these subdivisions contain many parcels that are just a few acres in size and relatively inexpensive. Previously populated mostly by white retirees, squatters and a few methamphetamine users and makers, the parcels were often bought sight-unseen as investments or potential retirement properties, with most remaining unsold and undeveloped until the mid-2010s. In 2014, these subdivisions became destinations for Hmong Americans from several places, including Minneapolis, Milwaukee and Fresno; many of them cultivated cannabis. The inexpensive, sparsely populated, rural subdivisions enabled Hmong-Americans to live in close proximity to ethnic and kin networks, which multiple interviewees expressed was especially important for elders who had migrated to the United States as refugees after the Vietnam War. The county sheriff estimated that since the mid-2010s around 6,000 Hmong-Americans had moved to Siskiyou, purchasing approximately 1,500 parcels . In an 86.5% white county with just 745 non-cannabis farms and fewer than 44,000 people , this constituted a major demographic shift. Hmong-American residents found themselves susceptible to scrutiny by white neighbors and officials.The subdivisions are often sparsely vegetated, dry and hilly, making them not only unproductive as agricultural lands but also highly visible from public roads, horseback, neighboring plots, helicopter and Google Earth. Green screen fencing, wooden stakes, portable toilets, generators, campers, plywood houses, or water tanks and trucks often signal cannabis cultivation but would be necessary for many land uses, especially since many lots are sold without infrastructure like water, sewer or electrical access. If detection of code violations depends upon visibility, Hmong Americans on subdivisions have been made especially visible and vulnerable to detection. One lawyer, for instance, reported that 90% of the defendants present at administrative county hearings for code violations in fall 2015, when the first complaint-driven ordinance was put in place, were Hmong-American. One Hmong-American resident reported being stopped by police six times in 3 months and subjected to unfriendly white neighbors patrolling on horseback for cannabis — one of whom made a complaint for a crowing rooster, a questionable nuisance in this “right to farm” county. Numerous Hmong-Americans and sympathetic whites echoed these experiences. County residents confirmed their antagonism toward Hmong-Americans by characterizing them in interviews and public records as dishonest, thieves, polluters, negligent parents and unable to assimilate, and making other racializing and racist characterizations. While written regulations and enforcement profess race neutrality, in a nuisance enforcement regime based on visibility, Hmong Americans were more visible than others, leading many to argue that they were being racially profiled. Rhetoric emerging from the county government amplified racial tensions and visibilities.

Numerous Sheriff’s Office press releases located the “problem” in subdivisions and attributed it to “an influx of people temporarily moving to Siskiyou” who were “lawbreakers” from “crime families” with “big money” and who threatened “our way of life, quality of life, and the health and safety of our children and grandchildren” . Just 2 days before the June 2016 ballot on the strict cannabis ordinances, state investigators responded to county reports that newly registered Hmong-American voters might be fraudulent or coerced by criminal actors and visited Hmong-American residences to investigate, accompanied by sheriff’s deputies . The voter fraud charges were later countered by a lawsuit alleging racially motivated voter intimidation; the suit was eventually dismissed for failing to meet the notoriously difficult criteria of racist intent. The raids may have discouraged some Hmong-Americans from voting, charges of fraud may have boosted anticannabis sentiment, and, one government official explained, “creative balloting” measures enabled some municipal voters in conservative localities to vote while others in more liberal places could not. The voter fraud charges, raids and legal contestation drew widespread media attention that further linked Hmong-Americans and cannabis. Amidst these now-overt racial tensions, the restrictive June 2016 ballot measure passed, allowing the Sheriff’s Office to gain full enforcement power over the “#1 public enemy to Siskiyou citizens … criminal marijuana cultivation” . Shortly after the June 2016 ballot measure affirmed stricter regulations, the Sheriff’s Office formed the Siskiyou Interagency Marijuana Investigation Team with the district attorney to “attack illegal marijuana grows” “mostly” around rural subdivisions . Within a month, SIMIT had issued 25 abatement notices and filed 20 criminal charges,flood table in addition to confiscating numerous plants. Meanwhile, the Planning Division’s role had diminished — code enforcement officers were relegated to addressing violations not directly related to cannabis . The November 2016 state legalization of recreational cannabis prompted Siskiyou to examine a possible licensure and taxation system for local growers .

Amidst sustained, vocal opposition, the proposal stalled for several reasons that further aggravated cultural and racial tensions: A key proponent of licensure was discovered to be running an unauthorized grow, three Hmong Americans died of carbon monoxide poisoning due to heaters in substandard housing, and a cannabis cultivation enterprise run by two Hmong-Americans attempted to bribe the sheriff. These developments were interpreted not as outcomes of restrictive regulations and criminalizing strategies, but as proof that, in the words of one supervisor, regulation was impossible until the county could “get a handle on the illegal side of things.” The sheriff encouraged this interpretation, arguing in an interview that statewide legalization was “just a shield that protects illegal marijuana” and efforts to regulate it would always be subverted by criminals. This antiregulatory logic prevailed in August 2017 when the county placed a moratorium on cannabis commerce. Still, the sheriff argued for stronger powers, citing an “overwhelming number of cannabis cultivation sites,” which, according to the Sheriff’s Office, continued to “wreak … havoc [with] potentially catastrophic impacts” across the region . Just 1 month later, at the sheriff’s urging, the Siskiyou Board of Supervisors declared a “state of emergency” aimed at garnering new resources and alliances to address the cannabis cultivation problem. Soon, the Sheriff’s Office enlisted the National Guard, Cal Fire and the California Highway Patrol in enforcement efforts, and, by 2018, numerous other agencies joined, including the Siskiyou County Animal Control Department, California Department of Toxic Substances Control, State Water Resources Control Board, California Department of Fish and Wildlife and a CDFA inspection station. These alliances multiplied the civil and criminal charges cultivators might face . Ironically, California’s cannabis legalization has enabled a kind of multi-agency neoprohibitionism at the county level, one that reinforces older criminal responses with new civil-administrative strategies and authorities. The need to “get a handle” might be regarded as a temporary emergency measure, but it may also propagate new criminalizing methods and institutional configurations. The more enforcement occurs, the bigger the problem appears, requiring more resources and leading to a logic of escalation symmetrical to the much-critiqued War on Drugs . And the more cannabis cultivators are viewed as criminal, the less likely they are to be addressed as citizens, residents and farmers.Given concerns about biased county policy and enforcement, the Sheriff’s Office held the first Hmong American and Siskiyou County Leader Town Hall in May 2018 to “foster a closer, collaborative relationship with members of the Hmong-American community,” exchange information about Hmong and Siskiyou culture and educate attendees on county policies . According to public records, racial tensions surfaced at this meeting when some white participants expressed that “our county” had been “invaded” and that Hmong-Americans were not fitting into local cultural norms . Meeting leaders — both government officials and Hmong-Americans — however, identified cultural misunderstanding, rather than criminalization and racialized claims by whites on what constitutes local culture, as the core problem to be addressed. “Misunderstanding” was an inadequate framing, given that Hmong-Americans had attempted to make themselves understood by attending public meetings, forming advocacy groups, signing petitions, demanding interpreters and administrative hearings, and registering to vote since their arrival in Siskiyou.

Posted in hemp grow | Tagged , , , , | Comments Off on Cannabis growers in Siskiyou’s subdivisions are especially vulnerable to detection

Further analysis is necessary to understand the potential impacts of well use on stream flow depletion

The use of well water for cannabis cultivation, in comparison to other water sources, presents both potential threats and benefits for in stream flow. In upper reaches of small watersheds, streams are dependent throughout the summer months on subsurface water flows from the landscape into the stream. Well water extraction may reduce cold water inputs — limiting stream flow or, in extreme conditions, dewatering stream channels . The extent to which use of subsurface water affects stream flow and water temperature depends on the degree to which well water sources are hydrologically connected to streams. When wells are shallower and closer to streams, and when soil conductivity is greater, subsurface water pumping is more likely to directly capture stream flow. However, if wells are less hydrologically connected to streams, the effects of extraction will be attenuated, resulting in smaller-magnitude and temporally lagged stream flow depletions. With sufficient groundwater recharge in wet months, well water extractions may affect stream flow less than surface water diversions, which were previously assumed to be cannabis cultivators’ predominant means of obtaining water in the region.Such an analysis would incorporate information on well locations and depths and would consider the underlying geology and soil properties at cultivation sites . Meanwhile, the prevalence and distribution of wells relative to other water sources are influenced by broader geospatial characteristics such as topography and precipitation patterns. Understanding these issues will also be important for assessing the threats and benefits associated with subsurface water extraction.

Variation between counties in well extraction patterns demonstrates that, although subsurface water may be the most common source of water in North Coast cannabis cultivation, the availability of alternative sources may play an important role. Humboldt County watersheds included in this study consistently receive more average annual precipitation than do those in Trinity , Mendocino and Sonoma counties . This difference translates into more available surface and spring water in Humboldt County over the course of the growing season. The observation that fewer sites in Humboldt County report well use, microgreen rack for sale compared to other counties in the study, suggests that if surface or spring water is available, cultivators are likely to use it. Conversely, the potential necessity of groundwater use in counties that receive less rainfall holds particular importance in consideration of emerging areas of industry growth throughout California. Further analysis is needed to understand how likely cultivators are to rely on wells if other sources of water are available to them. The winter preceding the 2017 growing season was the wettest on record. It is important to understand how cultivators may source their water during years in which summer water availability is not as abundant. These findings suggest that cultivators may utilize wells both as insurance against surface water scarcity in the summer drought months and as a means of achieving regulatory compliance. The observation that nearly one-third of non-compliant sites reported well extraction indicates that use of subsurface water may be a common means to avoid water scarcity in the late growing season. While Northern California receives considerable seasonal rainfall, there is also significant spatial variability in rainfall totals and in corresponding summer flow persistence of small streams . Considering the ephemeral nature of surface water in many areas , the increasing frequency of drought due to climate change and cannabis cultivation’s consistent demand for irrigation water as crops near harvest , cultivators are strongly motivated to secure reliable water sources for the entirety of the growing season. Therefore, it is likely that water extraction from wells is a common practice for cultivators, beyond those seeking participation in the regulated industry .

Although cannabis regulations place no explicit restrictions on where water is sourced, those currently within or seeking to join the regulated cannabis industry will be subject to a restriction on diversions of spring and surface water during the growing season . This requirement is already in place for permits issued by the California Department of Fish and Wildlife and will also be enforced by the State Water Resources Control Board beginning in 2019. The data provided in this study indicates that, in order to meet the forbearance period requirement, cultivators may be more inclined to drill a well to achieve compliance than to develop water storage for spring and surface water. Determining cultivators’ capability to store the water they need for the growing season may shed further light on the likelihood that growers will seek subsurface water. If compliance necessitates drilling a well, it will be important to account for the impacts of this potential shift in cultivation practices. Successful protection of freshwater resources in Northern California will require a more complete accounting of where cannabis cultivators source their water and the amount and timing of water extracted . Study of cannabis as an agricultural crop has been notoriously inadequate, but data provided by the water quality control board’s cannabis program offers critical new insights into the water use practices of cultivators entering the regulated industry. In this initial analysis, we found that subsurface water may be much more commonly used in cannabis cultivation than previously supposed. Further analyses of cannabis cultivation’s water extraction demand, as well as of geospatial variation in water demand, may help elaborate the ramifications of this finding. Ultimately, a better understanding of cannabis cultivation’s water demand will be useful for placing the cannabis industry in the greater context of all water allocation needs in the North Coast and throughout California.People living with HIV and those at increased risk for HIV are at high risk for other health problems, including substance use, mental health issues, and socioeconomic vulnerabilities.The COVID-19 pandemic and resulting efforts to curb the spread of infection—such as stay-at-home orders and physical distancing mandates—and the resulting social isolation are likely to exacerbate these issues.

A survey of young adults in the USA found that immediately following the declaration of a state of emergency due to COVID-19, levels of depression and anxiety increased with high levels of loneliness and COVID- 19-specific worry being associated with higher levels of depression and anxiety. Factors found to be associated with pandemic-related depression and anxiety include being younger, being a racial/ethnic minority, or being diagnosed with a chronic disease.The pandemic-related increases in mental health issues may also extend to substance misuse. Prior studies of disasters, including the aftermath of the 2003 severe acute respiratory syndrome epidemic, found increased rates of substance use. Emerging data related to the COVID-19 pandemic seem to corroborate these findings, with one study noting a “surge of addictive behaviors” including food, shopping, and increased reported use of cannabis, methamphetamine, and opioids. Studies that specifically focused on men who have sex with men —including both those who were HIVpositive and at increased risk for HIV—found that changes in substance use and mental health were also associated with behaviors that not only increased the risk for SARS-CoV-2 infection—the virus causing COVID-19—but also had implications in terms of STI/HIV transmission.For instance, one study found that those who had sex with casual partners during pandemic restrictions were more likely to report using substances including alcohol as compared to those who avoided interactions with casual sex partners. Engagement in ongoing health care and prevention is especially critical to the health of vulnerable populations living at the intersection of multiple colliding epidemics of COVID-19, substance use, mental health, and HIV. In order to reduce the potential for SARS-CoV-2 transmission, many clinics stopped in person clinical encounters and switched to telehealth visits starting in March 2020. While telehealth outcomes in general — including among those who live with HIV — have been largely positive, telehealth has the potential to miss the most high needs and socioeconomically vulnerable patients.Beyond limited access to technology requirements for telehealth visits including a cell phone or computer and Internet connectivity , privacy concerns and the absence of confidential surroundings may also be an issue. In fact, one study found that even with an intervention to improve telehealth attendance, access to virtual medical care was still challenging among people living with HIV who were experiencing homelessness.Therefore, cannabis grow facility layout the objective of this study was to assess the impact of the COVID-19 pandemic on substance use, changes in mental health, and interruptions in mental health care among HIV-positive and high-risk HIVnegative men. Specifcally, we focus on cannabis use given the high prevalence of use, ease of access, and its use as the substance of choice to manage negative affect including anxiety and depression.

We describe the prevalence and correlates of interruptions in mental healthcare as well as factors associated with cannabis use for COVID-19 related anxiety and depression. We compare those who report interruptions in mental health care to those who did not experience these interruptions and hypothesize that those experiencing interruptions in mental health care will experience increases in depression and anxiety and will also report other negative health behaviors, including increased substance use and increases in sexual risk behaviors.Data for this study were based on those collected from participants in the mSTUDY — a National Institutes of Health /National Institute on Drug Abuse funded cohort of racial/ethnically diverse, HIV-positive, and high-risk HIV-negative MSM. Details of the mSTUDY have been previously described,but briefy, participants were recruited from two study sites in Los Angeles, CA, including a community-based organization providing services for the lesbian, gay, bisexual, and transgender community and a community-based university research clinic. Study enrollment started in August 2014, and cohort participation is ongoing. Eligible participants were between 18 and 45 years of age at the time of enrollment, identifed as male at birth, if HIV-negative, reported condomless anal intercourse with a male partner in the past 6 months, were capable of providing informed consent, and were willing and able to return to the study site every 6 months to complete study-related activities. By design, half of the participants were living with HIV, and half were substance using. Following the COVID-19 pandemic “stay-at-home order” in California, all in-person research activities were stopped on March 13, 2020, and remote study visits were launched starting March 31, 2020. For this analysis, we included all participant remote study visit data collected from March 31, 2020, through August 30, 2021 .The Institutional Review Board at the University of California Los Angeles approved the study, and all participants provided written informed consent prior to study participation. During in-person study visits, which occur every 6 months, participants complete a self-administered, computer-assisted survey and provide biological specimen for HIV testing . During the remote visits included as part of this analysis, no biological samples were collected. HIV status was based on testing done at the previous follow-up visit, which occurred 6 to 8 months prior for most respondents. Participants were sent an electronic link to the study questionnaire for each remote study visit, which was comparable to the survey used as part of the in-person study visits and included additional questions related to the COVID-19 pandemic. In addition to sociodemographic characteristics, the questionnaire collected information on current substance use, mental health, sexual risk behaviors, and COVID-19 experiences and the impact of the pandemic on overall health and well-being.The impact of the COVID-19 pandemic has been vast in terms of who has been impacted and broad in terms of how people have been affected. Our findings highlight the experiences of those living at the intersection of multiple colliding epidemics and vulnerabilities, including COVID-19, substance use, mental health, and HIV. In particular, our results indicate increases in symptoms of depression and anxiety with the highest levels noted in the most immediate time frame following the COVID-19 pandemic and a reversion to pre-pandemic levels within 17 months of follow-up. Our results also indicate changes in substance use linked directly to experiences resulting from the COVID-19 pandemic, with a high proportion of participants reporting cannabis use to cope with their heightened anxiety and depression. Furthermore, we find that interruptions in care due to the COVID-19 pandemic, particularly interruptions in mental health care, can link with negative outcomes along substance use and STI/HIV risk and underscore the intersectional vulnerabilities experienced by these individuals.

Posted in hemp grow | Tagged , , | Comments Off on Further analysis is necessary to understand the potential impacts of well use on stream flow depletion

Our analyses revealed a high degree of support for the unidimensionality of cannabis use disorders

A prior genome-wide association study of DSM-IV cannabis dependence, conducted in the sample used in this study, failed to identify genetic variants at a statistically significant level . This has resulted in speculation regarding the biological underpinnings of cannabis use disorders; in particular, the question of whether common variation available in commercially available genome-wide arrays captures it . Aggregating the effects of all single nucleotide polymorphisms on commercial arrays might quantify the overall role of common SNPs as well as causal variants in linkage disequilibrium Table 1 Prevalence of individual DSM-IV and proposed DSM-5 criteria for cannabis use disorder in 3053 lifetime cannabis users of European-American and African American ancestry. When significant, this would indicate that heritable variation in the trait is at least partially captured by these SNPs in a highly polygenic manner. Applying this methodology, investigators have successfully attributed 23–51% of the variation in current smoking, major depression, schizophrenia and human intelligence to genetic influences . The present study uses a multi-pronged phenotypic and genomic approach to evaluate, respectively, the architecture and genetic underpinnings of DSM-5 cannabis use disorders, defined as a quantitative phenotype. Instead of relying on a diagnostic measure, we first utilize item response models to construct a factor representing liability to DSM-5 cannabis use disorders, while accounting for sex and ethnic differences. Second, we use this psychometrically constructed factor score in a genome-wide association analysis. Finally, we evaluate whether genome-wide SNPs and putative causal variants in linkage disequilibrium with them explain a significant proportion of the heritable variation in DSM-5 cannabis use disorders.The genotyping and quality control procedures applied to these data are explained in detail in earlier publications . In brief, DNA samples from 3988 individuals were genotyped on the Illumina Human 1 M bead chip by the Center for Inherited Diseases Research at Johns Hopkins University. As described earlier, 948,658 SNPs passed data cleaning protocols. No imputed data were used for these analyses. HapMap genotyping controls, duplicates, related subjects, and outliers were removed. For the current analyses, data on 3053 individuals reporting a lifetime history of cannabis use were used. Self-identified ethnicity was 2018 European Americans and 1035 African Americans.

We used MPlus to conduct exploratory and confirmatory factor analyses of the 12 DSM-IV/DSM-5 criteria in the same sample. Exploratory analyses were conducted in the full sample, while subsequent confirmatory factor analyses were conducted in African-American and European-Americans ,trim tray for weed separately by sex, using a multi-group framework. Initially, factor loadings and thresholds were constrained across the ethnic groups and across sexes. Individual sub-models were tested to determine whether allowing the factor loading and threshold for each criterion to vary across the groups resulted in a significant improvement in model fit. The model that accommodated all statistically significant differences was used to generate factor scores that were subsequently used for genome-wide association analysis.The sample used for analyses was restricted to those who reported at least one lifetime use of cannabis . These individuals are characterized with respect to the 12 individual DSM-IV/DSM- 5 criteria in Table 1. Prevalence of each criterion was higher in males than females for both ethnic groups, and males, regardless of ethnicity, were more likely than females to meet criteria for DSM-IV and DSM-5 diagnoses. However, several intriguing ethnic differences emerged. For both sexes, hazardous use, use of larger amounts or for a longer period of time and desire to quit or multiple failed quit attempts were differentially endorsed by EA and AA. EA men and women were more likely to endorse hazardous use and less likely to endorse using larger amounts or for longer than intended and failed quit attempts than their AA counterparts. In addition, tolerance, time spent using cannabis and the DSM-5 criteria of withdrawal and craving were more commonly reported by AA women than their EA counterparts—similar differences were not noted for men. The prevalence of DSM-IV cannabis abuse/dependence was higher in men compared with women, but no within-sex ethnic differences were noted. For DSM-5, cannabis use disorder was again more common in men than women, and there were no ethnic differences in men. However, AA women were more likely to meet criteria compared with their EA counterparts . Comparing the prevalence of DSM-IV vs. DSM-5 cannabis use disorders—within each group, very modest changes were observed. Decrease in overall prevalence was noted for EA, while AA women showed a slight increase and AA men remained unchanged. Examining the [95%] confidence limits for the point estimates, only the decrease in prevalence in the EA was statistically significant while the estimates in AA subjects could be equated across diagnostic classification scheme .An exploratory factor analysis of the full sample revealed that a single factor solution provided a reasonable fit to the data : 0.996, root mean square error of approximation : 0.054. While a 2-factor exploratory solution modestly improved these fit indices,the inter-factor correlation was 0.90. Hence, we proceeded with the more parsimonious single factor confirmatory analysis, which readily approximates item response parameters.

Confirmatory factor analysis of the 4 DSM-IV abuse, 6 DSM-IV dependence and the DSM-5 withdrawal and craving criteria revealed high factor loadings for all criteria except legal problems , which was excluded from further analyses comparing factor loadings and thresholds for each individual criterion across EA and AA males and females. The factor loadings and thresholds from the model allowing for statistically significant differences across individual items are shown in Table 2. Factor loadings and thresholds could not be constrained across the groups for hazardous use,interpersonal problems, withdrawal,using more than intended , repeated/failed quit attempts,time spent and physical/psychological problems . Factor scores that accommodated these differing thresholds and factor loadings were created for each of the four subgroups and used for genomic analyses.Individual signals did not surpass the Bonferroni corrected genome-wide significance threshold of p < 5 × 10−8. The results for the top 20 SNPs are presented in Table 3 . For the EA sub-sample, 11 SNPs on 17q23-24 appeared to be associated at nominal levels of significance although none surpassed the genome-wide threshold of 5 × 10−8.The top SNP, rs6504555, was an intronic variant in the bromodomain PHD finger transcription factor gene—a regional association plot for this region of chromosome 17 is shown inFig. 1, indicating a high degree of linkage disequilibrium across the associated SNPs. With the exception of rs11870068, the remaining chromosome 17 SNPs were in moderate to high linkage disequilibrium . In the AA sub-sample, results did not aggregate in any particular chromosomal region. The most significant SNP, rs4364205, on chromosome 3, was intergenic. Meta-analysis of the results from the EA and AA sub-samples did not yield a boost in statistical significance . This was evident from a comparison of results in the EA and AA sub-samples. Of all SNPs with p-values < 0.05 in EA sub-sample, only 5% had corresponding p-values < 0.05 in AA sub-sample. However, particularly for the SNPs for the EA sub-sample shown in Table 2, the direction of effect in the AA sub-sample predominantly concurred with the EA sub-sample.We sought to examine the phenotypic and genomic architecture of a continuously distributed cannabis use disorders factor, psychometrically derived from DSM-5 criteria, in samples ascertained for alcohol, nicotine and cocaine dependence.Analysis of ethnic differences indicated a modest reduction in the prevalence of DSM-5 cannabis use disorders, relative to DSM-IV, in EA. Genomic analyses, using a genome-wide scan, failed to identify SNPs that satisfied statistical thresholds for significance; however, gene-based association implicated genes on the q-arm of chromosome 17. A genome wide variance calculation revealed that 21% of the phenotypic variance in cannabis use disorders was captured by the available common variation on the genome-wide array, but this estimate had a large standard error and was not significant. We used the factor score as our phenotype for genomic analyses.

Incorporating withdrawal and craving, excluding legal problems and combining across DSM-IV abuse and dependence criteria, this factor embodies the ‘spirit’ of the new DSM-5 diagnostic scheme while not being encumbered by concerns that the threshold of 2 or more criteria for diagnosis of disorder is too lax . From a psychometric perspective, our results are consistent with the extant literature . For instance, despite our sample being ascertained for alcohol, nicotine and cocaine dependence, which inflated endorsement rates of individual criteria , our high rates of hazardous use were comparable with those reported for lifetime cannabis users from the general population as reflected in data from the National Epidemiological Survey of Alcohol and Related Conditions . Likewise, broadly consistent with numerous other studies, the DSM-IV abuse criterion of legal problems was infrequently endorsed and had a weak factor loading, affirming its proposed exclusion from DSM- 5. The overall prevalence of the remaining criteria, although much higher than in general population cohorts, supports the presence of a unidimensional construct across sexes and ethnicities. Craving and withdrawal, both of which have been added to DSM-5, performed well, with high factor loadings supporting their inclusion. Overall, trimming tray weed rates of diagnostic DSM-5 cannabis use disorders appear to be modestly lower than those for DSM-IV abuse/dependence, but only in EA, particularly men. This finding is highly comparable with epidemiological analyses of alcohol symptomatology in U.S. and with results from the 2007 Australian National Survey of Mental Health and Well being, which reported a decrease in the lifetime rate of cannabis use disorder from 6.2% to 5.4% when transitioning from DSM-IV to DSM-5 . In our sample, this decrease was uniformly attributable to individuals who endorsed hazardous use alone, which results in a DSM-IV diagnosis of cannabis abuse but not a DSM-5 diagnosis of cannabis use disorder, because it falls below the latter’s minimum two-symptom threshold. No differences were noted in AA men , and this is also not surprising. Individuals endorsing this criterion alone tend to be of higher socio-economic standing and tend to, overwhelmingly, endorse this criterion due to a history of drinking and driving . That socio-economic status may correlate with ethnicity is expected—in our data, 45.9% of AA participants reported a gross annual income of less than $20,000, vs. 15.4% of their EA counterparts. Upon examining gender and ethnic differences within classification version , the only significant variation was noted for DSM-5 diagnoses in AA women who were more likely to receive a diagnosis of DSM-5, but not DSM-IV cannabis use disorder, relative to their EA female counterparts. Intriguingly, also relative to their EA counterparts, they were less likely to endorse hazardous use but more likely to endorse numerous other criteria, with the exception of giving up important activities and use despite physical/psychological problems. This finding may be attributable to the larger number of AA women that were ascertained from the cocaine dependence study vs. other studies. Although this observation holds true for the men as well, and the prevalence did not vary across AA and EA women, it is possible that AA women from the FSCD study represent a high-risk group. For instance, when compared to the alcohol and nicotine dependence studies, AA women from the cocaine study were more likely to report lower household income and a greater likelihood of less than a high school education . Thus, this vulnerability might reflect environmental adversity rather than increased genetic susceptibility, and in any case, is accounted for in the genomic analyses by incorporating study sample and gender as covariates. From a genetic perspective, the single SNP analyses did not reveal any genome wide significant signals. This is likely because our sample is under powered, even with a quantitative trait, to detect single variants of modest effect size. Using GWA Power , we estimated power available in our dataset to identify SNPs of varying effect size. Power was 80% when an effect size of 0.01 was anticipated . Increasing efforts to amass larger samples with comparable cannabis-related data would afford greater power to detect variants of more modest effect size via meta- and mega-analyses. However, few current studies have DSM-5 criteria data. In this regard, factor scores such as ours may prove to be useful phenotypes as they can accommodate DSM-IV and DSM-5 based assessments of vulnerability to cannabis use disorders. In contrast,the gene-based analyses conducted with the EA sub-sample identified a cluster of genes, of varied function, on the q-arm of chromosome 17 that appeared to contain an aggregation of variants associated with DSM-5 cannabis use disorders.

Posted in hemp grow | Tagged , , | Comments Off on Our analyses revealed a high degree of support for the unidimensionality of cannabis use disorders

The prevalence of marijuana use was 72% prior to graduate school enrollment and 49% after graduate school enrollment

Existing theories of student attrition, centered primarily on the undergraduate student experience, posit that attrition is influenced by individual, institutional, and social factors . Institutional factors include program characteristics, administrative policies, and academic requirements, and social factors include peer culture, faculty/staff interactions, and social integration. Individual pre- and post-matriculation factors include demographic characteristics, skills and abilities, goals and expectations, external commitments, and academic history. Largely missing from theories of student attrition are health status and health behaviors, particularly substance use prior to and after enrollment in an academic degree program. The relationship between alcohol and marijuana use and graduate degree completion is likely influenced by demographic characteristics. Both heavy drinking and marijuana use are more prevalent among college males than females , and substance use disorders are associated with being male, white, and unmarried . Having children is associated with a lower prevalence of substance use among both men and women . Demographic characteristics are also associated with graduate school completion, with burnout and attrition highest among women . Attrition is also more common among African-American/Black students , domestic students , and students enrolled in master’s degree programs . This study aimed to fill a gap in the literature by assessing the relationships between alcohol and marijuana use before and after graduate school enrollment and graduate degree completion. It is hypothesized that lower levels of alcohol and marijuana use both before and after graduate school enrollment are associated with graduate degree completion after adjustment for potentially confounding variables.The College Life Study is a longitudinal study of young adults who were recruited from a large, mid-Atlantic university. During the first stage of sampling, a ten-minute survey was administered to all incoming first-time, first-year students ages 17 to 19 that contained questions on demographic characteristics and tobacco, alcohol, and other drug use behaviors. During the second stage of sampling, the sample was stratified by race, gender, and substance use history. Students who had tried a drug or used a prescription drug non-medically at least once prior to college entry were over sampled. A random sample was chosen for longitudinal follow-up, and 1253 students completed a personal interview at baseline [Year 1 ; modal age 18].

Follow-up assessments were then conducted annually from Years 2 through 8 and then again in Years 10 and 12 through face-to-face interviews, self-administered surveys, and web based surveys. Follow-up rates were high,grow tent for sale ranging from 91% in Y2 and 73% in Y12. The university’s Institutional Review Board approved the study, and informed consent was obtained. Additional detail on recruitment methods and follow-up procedures can be found elsewhere . From the original sample of 1253 young adults, 541 participants enrolled in a degree-seeking graduate program at some point by Y10 of the study. Of these, 21 participants were excluded from analyses. Five of these participants were excluded because upon further examination of other assessment responses, they had listed graduate school enrollment by mistake, and one participant was excluded because information on their specific graduate degree type could not be identified. In addition, to ensure participants had adequate time to complete their degree, 15 participants who first enrolled in a doctorate or professional degree program in Y10 were excluded, giving a final analytic sample of 520 participants.Alcohol use was measured annually in Y1-Y12. To assess frequency of alcohol use, participants were asked, “In the past 12 months, on how many days have you drank any drink with alcohol in it?”. To assess quantity of alcohol use, participants were asked the number of drinks they had on a typical drinking day . Data on days used during the past year were used to estimate average alcohol use frequency for descriptive purposes. Marijuana use frequency was assessed annually in Y1-Y12 with the question “In the past 12 months, on how many days have you used any type of marijuana?” . Data on days used during the past year were used to estimate average marijuana use frequency for descriptive purposes. Past-month frequency of both alcohol and marijuana use were also assessed, but because of the high degree of correlation with past-year measures , only past-year variables were used in the analyses. For each participant, alcohol use frequency, alcohol use quantity, and marijuana use frequency were averaged separately for each of two time periods: before and after the first year they indicated enrollment in a graduate degree program. The mean for each of the six separate variables was used to capture variation in substance use during the pre- and post-enrollment periods, particularly because the before enrollment period included the undergraduate college years as well as the interim years after college graduation but before graduate school enrollment.Gender was coded by the interviewer in Y1 as either male or female. Race/ethnicity was measured in Y3, and response options included white; Black/African-American; American Indian or Alaskan Native; Native Hawaiian; Other Pacific Islander; Asian; and Hispanic, Latino, or Spanish. Participants could also write in a response or choose “Don’t Know/Refuse to Answer”. Given that the majority of the sample was non-Hispanic white, race was dichotomized into white and nonwhite. Marital status was measured in Y4-Y8, Y10, and Y12.

Participants indicated whether they were married, divorced, widowed, separated, in a civil union or domestic partnership, or never married. A dichotomous variable was created to represent whether or not participants were married at any point during Y4-Y12. The number of children participants had was measured in Y4-Y8, Y10, and Y12. A dichotomous variable was created to represent whether or not participants ever had children by Y12.Descriptive statistics were used to analyze the distributions of all study variables. Pearson correlation coefficients were used to analyze the relationships between all six alcohol and marijuana use predictor variables. A series of logistic regression models were fit to assess the relationships between alcohol and marijuana use and graduate degree completion. First, in Stage 1, separate logistic regression models were fit to analyze the relationships between each alcohol and marijuana use predictor variable and graduate degree completion while controlling for demographic and program characteristics. Second, in Stage 2, a best- fitting model was obtained by entering each of the six alcohol and marijuana use predictor variables into the model one at a time, retaining any predictor variable that was statistically significant and dropping those that were not significant. All demographic and program characteristic variables were retained in the final model regardless of significance. The Nagelkerke R2 value was used to examine the variance in graduate degree completion explained by the Stage 2 variables. A similar method has been used in prior work by the research team . SPSS Version 24.0 was used for all analyses, and the alpha level was set at 0.05.The majority of the sample was female and non-Hispanic white , with 42% of participants getting married and 14% having children by Y12 . About two-thirds had enrolled in master’s degree programs and 31% had enrolled in doctorate or professional degree programs, with Y5 as the most common year to begin graduate school. The majority of the sample completed their graduate degree by Y12.The majority of participants drank alcohol during at least one year before graduate school enrollment and after graduate school enrollment . Among drinkers, the average alcohol use frequency was about 75 days during the past year before enrollment in graduate school and 88 days during the past year after enrollment . Among drinkers, mean alcohol use quantity decreased from a mean of 3.9 drinks per drinking day before graduate school enrollment to 2.6 drinks per drinking day after enrollment. The typical quantity consumed for male drinkers was greater than female drinkers both before and after graduate school enrollment . Based on past-year data, it was estimated that about 35% of drinkers drank less than weekly and about 24% drank twice a week or more before graduate school enrollment.

After graduate school enrollment, 32% of drinkers drank less than weekly and about 31% drank twice a week or more.As seen in Table 2, marijuana use frequency among users was about the same prior to and after graduate school enrollment with a mean of about 40 days during the past year. Among those who used marijuana prior to graduate school enrollment, 56% used once a month or less and about a quarter used at least weekly . Among those who used marijuana after graduate school enrollment, 64% used once a month or less and about 18% used at least weekly . The correlations between the six alcohol and marijuana use predictor variables are presented in Table 3. There were moderate to strong correlations between the before enrollment estimates and the after enrollment estimates. Despite this statistical overlap, both before and after enrollment variables were retained due to their importance to the research question of interest. Alcohol use frequency before graduate school enrollment was strongly correlated with alcohol use quantity before graduate school enrollment and moderately correlated with alcohol use quantity after graduate school enrollment . To avoid the potential for multicollinearity effects on the statistical models, only the alcohol use frequency variables were retained for further analyses. There is prior evidence that frequency of alcohol use increases during the post-college period while quantity of alcohol use decreases ,indoor grow tent and alcohol use frequency has higher sensitivity and specificity in identifying alcohol-related problems than alcohol use quantity .Stage 1 results showed that, even after controlling for demographic and program characteristics, marijuana use frequency after enrollment was negatively associated with graduate degree completion . The best-fitting model included alcohol use frequency before graduate school enrollment and marijuana use frequency after graduate school enrollment, which were both significantly associated with graduate degree completion after being entered into a model together and with the demographic and program characteristics. Alcohol use frequency before enrollment was positively associated with the odds of graduate degree completion . In contrast, as marijuana use frequency after enrollment increased, the odds of graduate degree completion decreased . In the best-fitting model, gender, marital status, and first year of graduate school enrollment were associated with graduate degree completion.

Female students had almost two times higher odds of graduate degree completion when compared with male students, and married students had more than two times higher odds of graduate degree completion when compared with those who had never been married. In comparison with students who began their graduate degree in Y10 , students entering graduate school in Y5 , Y6 , and Y7 had significantly higher odds of graduate degree completion. 4. Discussion This study examined whether or not alcohol and marijuana use before and after graduate school enrollment were associated with graduate degree completion. Alcohol and marijuana use were moderate among participants in this sample. Results showed that more frequent marijuana use after graduate school enrollment was associated with decreased odds of graduate degree completion after adjustment for potentially confounding variables. This finding is consistent with prior research that has shown a relationship between frequent marijuana use and degree non-completion among high school and undergraduate college students . Marijuana use was less prevalent after graduate school enrollment as compared with before, which is consistent with research showing that marijuana use declines as young adults age . However, while past-year marijuana use frequency among marijuana users who completed their graduate degree declined from 40 days before enrollment to 35 days after enrollment, frequency among users who did not complete their graduate degree increased from 45 days before enrollment to 85 days after enrollment. There are several mechanisms through which marijuana use might affect degree completion. The first is through decreased academic performance, with underachievement cited as the most well-supported correlate of marijuana use . While little research has been done on the relationship between marijuana use and decreased academic performance among graduate students, existing evidence among high school and college students shows that frequent marijuana use is associated with academic unpreparedness , lower grades , and lower academic achievement . The relationship between marijuana use and degree non-completion might also be explained by the effects of marijuana use on cognition .

Posted in hemp grow | Tagged , , | Comments Off on The prevalence of marijuana use was 72% prior to graduate school enrollment and 49% after graduate school enrollment

The advantage of hybrid fiber-reinforced composites is that they benefit both synthetic and natural fibers

Mitochondrial dysfunction and oxidative stress are two factors that are thought to play a significant role in the development of PD. As seen in Fig. 1, rotenone and H2O2 both induced dose dependant decreases in cell viability in the TH1 transfected SH-SY5Y cells. The concentrations of rotenone and H2O2 needed to induce this change were higher than those noted in previous studies using the SHSY5Y cell line; this could be due to the transfection of TH1 within these cells incurring increased resistance to rotenone. This hypothesis is supported by our previous studies using the TH1 transfected SH-SY5Y cell line reporting an increased resistance to oxidative stress and treatment with 6-OHDA and H2O2.Cleavage of PARP-1 is commonly used as an index of apoptosis. In this study, treatment with rotenone and H2O2 both induced a dose dependent increase in PARP-1 cleavage indicating the occurrence of apoptosis. Interestingly while oxidative stress is thought to play a major role in cell death induced by both rotenone and H2O2, the two toxins had significantly different effects on TH expression. Rotenone induced an increase in TH expression within our SH-SY5Y cells, this is in contrast to previous studies that suggest rotenone treatment results in a decrease in TH expression in both animal models and cells.It should be emphasised, however, we measured TH protein only in the cells that were still attached to the bottom of the plate but not in the cells that had detached from the plates as these were removed with the media at the completion of rotenone treatment. Therefore, our results suggest that TH protein was increased only per remaining cell and not per total number of cells present at the beginning of the treatment. In contrast H2O2 had no effect on TH protein levels in the remaining cells, suggesting that while oxidative stress may play a role in rotenone induced cell death, the increase in TH seen was not induced by it. Rotenone is also thought to cause inhibition of the proteasome system,grow tent therefore it is possible that the levels of TH protein are increasing in these cells because breakdown and removal of the protein have been altered; however, this requires further investigation. Natural compounds with antioxidant and anti-inflammatory properties have become of interest with regards to PD as the current treatments are associated with harmful side effects.

Curcumin, cinnamon, hemp seed and Polygonum cuspidatum are all naturally occurring products that have been used in traditional Chinese medicine for many years.We found that pre-treatment of our SH-SY5Y cells with compounds isolated from these products did not have an effect on rotenone toxicity. This is in contrast to previous studies that have demonstrated the protective effect of curcumin against rotenone in SH-SY5Y cells.It should be noted that while both studies have utilised SH-SY5Y cells, our cells contain human TH1. Therefore, it is possible that the transfected TH1 and the increase in TH protein expression seen with rotenone treatment could be potentiating rotenone induced cell death and playing a role in our inability to protect against rotenone toxicity. As TH is the rate limiting enzyme in DA synthesis, it is possible that the increased TH protein expression in response to rotenone could have induced an increase in DA production. The increased DA could possibly accumulate within the cytoplasm of the cells and lead to increased oxidative stress, proteasomal inhibition and mitochondrial dysfunction that could be contributing to rotenone induced cell death. This hypothesis is similar to a popular hypothesis that suggests an involvement of hyper-activation of TH and DA production in early PD pathogenesis.Interestingly, the same compounds did display the ability to protect against H2O2 induced toxicity. In addition, all tested compounds also prevented the increase in PARP-1 cleavage seen with H2O2 treatment indicating a reduction in apoptosis and supporting the findings of the viability assay as well as the findings of previous studies that suggest the novel compounds possess antioxidant activity.Moreover a previous study has demonstrated the ability of cinnamaldehyde to modulate the release of catecholamines from a rat pheochromocytoma cell line,indicating this compound has the potential to not only be neuroprotective but may also further ease the symptoms of PD by promoting catecholamine release. While the in vitro antioxidant capabilities of these compounds have been demonstrated previously, this is the first study to demonstrate the neuroprotective properties of cinnamaldehyde, caffeoyltyramide and piceatannol glucoside in a dopaminergic cell line in response to H2O2. In summary, we demonstrated that the effect of rotenone on these cells is more complicated than just the induction of oxidative stress and suggest that perhaps TH may be involved. Curcumin, cinnamaldehyde, caffeoyltyramide and piceatannol glucoside successfully prevented H2O2 induced cell death, making this the first study to demonstrate the neuroprotective potential of these natural compounds in a SH-SY5Y cellular model of oxidative stress.

The combination of traditional and man-made fiber-reinforced composites provides many advantages in different areas of engineering and technology. The commonly used natural fibers in engineering fields are sugar palm, flax, sisal hemp, kenaf, and Abaca fibers. Incorporating natural fibers in high-strength synthetic fibers like carbon and Kevlar improves mechanical properties, namely, stiffness, toughness, moisture resistance. The properties of composite specimens have been enhanced due to addition of nanomaterials and lignocellulose fibers as reinforcement in composites.The properties of composites depend on the individual element characterization like matrix and fibers type, chemical properties of matrix and fibers. The hybrid reinforced polymer composite consists of natural and synthetic fibers with short fiber and random orientation and long fiber in mat form. In short and randomly oriented fiber-based composite, the sliced fibers are mixed in a fixed quantity of thermoplastic resin, melt mixer is used for homogeneous mixing. The product taken from the mixing chamber is a chunk form of fiber-based polymer composites. The small pieces of fiber/ matrix composites are obtained from different techniques: the pultrusion process and injection molding. The different research articles have been available based on the characteristic study of fiber-based composite by varying fibers and resins, fibers length. This type of chopped fiber-based composite fabrication can be used to reduce wastage because of small size of fibers, and also it is economical. The hybrid composite consists of two or more different fibers. Sid ika et al. found the experimental results such as impact, flexural, and tensile strengths of natural fibers, namely, Jute and Coir reinforced polypropylene resin composites. It has also been found from experimental results that variation of fiber content by weight fraction such as 25:75, 50:50, 75:25 in the overall loading fibers and the matrix content remains constant. Likewise, Ranjan et al. carried out research on hybrid fibers reinforced polylactic acid resin composite and found the results, namely, tensile, flexural, and impact strength. Additionally, the investigators observed that the strength of the Sisal/Banana fibers was reduced due to the presence of weak adhesive bonding between the fibers and polylactic acid. It creates lower-strength materials. Per z et al. reported the optimum strength and modulus obtained by varying the weight fraction of banana and coir fiber content in fiber-based composite. In addition, 15% of the coir fiber-reinforced polymer composite gives good impact properties, 10% of coir fiber reinforced polymer composites provide the best modulus and strength under the flexural and impact forces. Per z et al. reported a similar enhancement of results in impact strength.

Especially the coir fiber content contributed more to the improvement of impact properties in composite due to the following reason at higher fiber loading, it requires high energy to break the fibers or fiber pullouts high lingocellulosic content. The composite strength and modulus may be reduced at higher fiber loading due to the non-maintaining homogenous distribution of fiber content, which causes agglomeration in the region. The agglomeration region acts as a stress concentrated region, and it is responsible for the initial crack to the failures. The following are the disadvantages of the natural fibers, lower strength, weaker inter facial bonding, hydrophilic and hydrophobic nature of fiber and matrix, respectively. To enhance the mechanical properties of natural fiber reinforced polymer composites following ways can be adopted, i.e., fiber treatments, the addition of synthetic reinforcements, and coupling agents. The long fiber reinforced polymer matrixes have been made from prepregs or woven mats. The prepregs have formed by the melting and pressing fiber fabrics at high temperatures. The final form of long fiber reinforced polymer composite is formed by stacking the prepregs layer by layer. Kar dumen et al. reported the influence of stacking sequence on the mechanical properties by using woven flax and non-woven jute fiber reinforced on the polypropylene resin. They said additionally that the hybrid composite consists of non-woven jute covered by woven flax, which exhibits good strength. In contrast, the hybrid materials consist of woven flax covered by the non-woven jute, displaying good impact strength. Addition of the 10% glass fiber in jute fiber reinforced polypropylene composite has improved tensile and flexural strengths. Dan Mallam et al. fabricated the hybrid composite from the kenaf fiber and polypropylene terephthalate matrix; the two types of hybrid composite, namely woven interplay and interwoven. Amo g the two kinds of hybrid composite, the interwoven ply exhibit good tensile and flexural properties,grow tent complete kit while the woven interplay displays good impact properties. It is summarized from kinds of literature that the highest mechanical properties of the synthetic and natural fibers in Kevlar and Abaca fibers respectively, also very few works have been done in hybrid composites, however, no work has been carried out in the combinations of the Kevlar and Abaca.

Similarly, Glass and Hemp fibers also have specific advantages compared to other fibers. In this work, an attempt has been made to bring benefits of both synthetic and natural fibers in hybrid composites. The mechanical properties namely tensile, flexural, and impact testing, have been performed numerically and experimentally. Aba a, Hemp, Glass, and Kevlar fibers have been used to prepare the composite specimens. The hybrid composite materials consist of Glass/Abaca, Glass/Hemp, and Kevlar/Abaca.In this work, all four fibers, namely, Abaca, Hemp, Glass, and Kevlar fibers, were purchased in the form of long fiber. The thickness of the Abaca fiber is 0.35 mm, length is 200e300 mm, which is obtained from the stem of pseudostem of Musa sepientum. Yellowish Kevlar 49 grade with bidirectional woven fabric has been used, Hemp fibers, with the thickness of 0.08 mm and length of 15e35 mm have been used, Glass fiber in mat form, length of 6e12 mm and 0.01 mm diameter. All fibers were purchased from Vruksha composite, Chennai, Tamilnadu. The hybrid composites were fabricated by alternating natural and synthetic fibers into the matrix. In the present work, epoxy resin was used as a matrix material. The liquid resin is a colorless, highly viscous liquid, at 25 C the density and viscosity are 1.16 gm cm 3 and 900 cps, respectively. Harer is used to reduce the curing time, namely, Amine purchased from Bangalore-based company, namely, Naptha resin and chemicals. The natural fibers are purchased from Maruthi Peach Company, Tirupur district, Tamil Nadu, India. The synthetic fibers, namely Kevlar and Glass fibers, are purchased as yarns from Go Green products, Coimbatore, Tamilnadu, India, and weaved of fibers alternatively with 6.7 6.7 yarns per cm. The composite specimen is bidirectional, and the bulk and linear densities were used to calculate the cross-section of yarns. The cross sectional area of yarn is 0.015 cm2 . The area is calculated by dividing linear density by its bulk modulus. The density of the different fibers is listed in Table 1.The three different combinations of natural and synthetic fibers-based composites were prepared. The following loads were applied: tensile, flexural, and impact; then, results were reported. In each experiment, three times repeated and took the average value for the graph. A similar work has been carried out by Mohanavel et al., who characterize the mechanical properties of the hybrid composite, which consists of Glass, Jute, and Madar fibers. Also, they fabricated the hybrid composite with a similar type of stacking sequence, that is, the first and last layer was synthetic fibers, due to the lesser water-absorbing characteristics of the fibers.

Posted in hemp grow | Tagged , , | Comments Off on The advantage of hybrid fiber-reinforced composites is that they benefit both synthetic and natural fibers

Women have shown slightly more severe neurocogntive deficits related to marijuana use compared to men

This report focuses on spectroscopy findings.In addition to the K-SADS-PL,the Personal Experience Inventory was used to further assess alcohol and marijuana use in both the MJU group and in the healthy controls.Briefly,the PEI consists of two main sections,one focused on patterns and severity of substance use,and the other focused on psychosocial consequences of use.In most cases,participants endorse items from the inventory using a four-point Likert response format.Different versions of the PEI have been developed for adolescents versus adults.Participants younger than 18 years of age received the adolescent version and participants older than 18 years of age received the adult version; both versions were computer administered.All MJU participants received the adult version.Scoring was implemented to create comparable metrics across the two versions.Finally,an in-house questionnaire based on guidelines provided by the National Institute on Alcohol Abuse and Alcoholism was implemented to assess detailed daily,weekly,yearly and lifetime use patterns of alcohol and marijuana in the sample,considering frequency and amount of use.The MR spectroscopy voxel was positioned in the right basal ganglia using the T1-weighted image.The caudate and putamen were the primary regions of interest.The voxel was positioned in the following way: left/right—the voxel was positioned so that it was as medial as possible,without containing any portion of the lateral ventricle,anterior/posterior—the voxel was positioned as anterior as possible in the caudate,without entering the anterior horn of the lateral ventricle,superior/inferior—the voxel was positioned such that the inferior portion of the voxel was as close as possible to the most inferior aspect of the putamen,and such that the superior portion of the voxel was approximately 3 mm inferior to the most superior aspect of the caudate.Fig.1 illustrates the voxel placement in a typical subject.confirmation of consistent voxel placement across subjects was achieved by segmenting and parcellating the T1-weighted image.

A high-resolution structural scan was acquired to position the voxel during data acquisition and to determine the tissue composition of the voxel through segmentation.The T1-weighted scan was processed using the standard Free Surfer pipeline for tissue segmentation and anatomical parcellation.Further details related to the Free Surfer processing can be found online,and in one of our previous publications.In-house software was used to compute the transformation matrix from the scanner coordinates to the FreeSurfer-processed T1-weighted image.A mask representing the spectroscopy voxel in the anatomical image space was then created using tools from the FMRIB Software Library,planting racks which was subsequently segmented and parcellated using the Free Surfer anatomical information.Thus,each T1-weighted voxel within the spectroscopy volume,was classified as either white matter,gray matter,cerebrospinal fluid,or non-brain,and was further parcellated into subcortical and cortical structures.This was done to confirm a consistent voxel placement across all subjects and to determine the basic tissue composition within the voxel.Further details of the voxel composition can be found in the results section below.Data were analyzed with the Statistical Package for the Social Sciences,version 19.Data were examined for normality in order to ensure appropriateness of parametric statistics.Univariate analyses of covariance were used to test group effects between the MJU individuals and the controls,with age and alcohol use entered as co-variates.Group and sex were both entered as between-subjects variables.Alcohol use frequency over the past 12-month period summarized by the PEI was used in the above model as the alcohol use co-variate.Two-way interaction effects between group and sex,when present,were examined further by running the model separately in males and females,or by examining sex effects within MJU individuals and controls.Finally,significant effects were re-evaluated by matching the MJU and control samples by age to verify that patterns remained significant with more stringent control over developmental differences that might otherwise impact the findings.There was no group by sex interaction for age or for IQ.

Marijuana users were college students of middle to high-middle socioeconomic backgrounds and most were free of a non-substance DSM-IV Axis I diagnosis.None were psychotic.Nearly all met DSM-IV diagnostic criteria for marijuana abuse or dependence.Use of other recreational drugs within the MJU group was limited,with no participants meeting DSM-IV criteria for abuse or dependence.One subject met diagnostic criteria for current alcohol dependence,and a small proportion met criteria for alcohol abuse.Compared to controls,alcohol use over the past twelve months use was found to be significantly higher in the MJU group,F = 43.93,p b 0.001.Marijuana users on average had a PEI score of 3.7,which corresponds to endorsing use of alcohol between 21 and 100 times in the previous 12 months.Controls on average had a PEI score of 1.5,which corresponds to endorsing use of alcohol between 1 and 20 times in the previous 12 months.When the sample is restricted to include only individuals aged 17 and higher,the difference in alcohol use remains significant but the mean value for control participants is slightly higher at 1.9.Thus,the amount of alcohol use endorsed over the past twelve months was entered as a covariate in analyses comparing metabolite concentrations between groups.The marijuana users reported that their age of first use of marijuana was 15.2 ± 1.2 years,and also reported smoking 9.8 hits per day during the past year.In addition,supplemental analyses were conducted to verify that female users did not differ from male users in their self-reported patterns of use,age of use onset,use of alcohol,or symptoms of psychopathology.Findings are presented in Table 3.The only group difference to emerge was that female users reported fewer symptoms overall of alcohol abuse/ dependence than did males.Otherwise,they did not significantly differ in variables that would suggest an increased frequency or duration of marijuana use,use of other substances,or presence of concomitant psychopathology.The spectroscopy voxel was consistently placed in the same anatomical location,centered in striatum,in both marijuana users and controls.

The voxel was primarily composed of gray matter,as determined by the Free Surfer parcellation procedure.The majority of the voxel composition was statistically similar between groups,with the exception of the pars opercularis,which accounted for less than 1% of the total voxel composition.The remaining 2% of the voxel composition was relatively variable.Moreover,these additional regions always represented very small amounts of tissue,and were not represented in all subjects.This study examined a cohort of college-aged heavy marijuana users and a control group of non-using young-adults.Using MR-spectroscopy,it was shown that females,but not males,who used marijuana heavily starting in mid-adolescence and persisting for several years have lower levels of glutamate and glutamine in the dorsal striatum when compared to controls,even after accounting for age and alcohol use.Similarly,female but not male users differ from controls in their estimated concentrations of myo-inositol,demonstrating higher levels than controls.These patterns are interpreted as pathological in the female users given that male users had comparable levels to controls of both sexes.Female users did not differ from male users in their overall rates of self-reported marijuana use,in their concomitant level of alcohol use,in their numbers of symptoms of marijuana dependence,or presence of other conditions that might impact brain metabolism.These findings have broad parallels in the extant literature,both in relation to the overall patterns observed but also in relation to sex differences.Decreased glutamate/glutamine concentrations have been reported in two other MRS studies of marijuana users,one that focused on the basal ganglia and one that targeted the anterior cingulate cortex.First,in an older cohort of marijuana users than is described in the current study,Chang et al.reported lower glutamate levels in the basal ganglia,suggesting that heavy marijuana use during young adulthood as well as later in life is associated with disruptions in glutamate signaling as has been shown for other drugs of abuse.Recently,Prescot et al.reported lower glutamate concentrations in the anterior cingulate cortex,which was nonetheless strongest when females were eliminated from the analysis.Interpretation of the current findings is complicated by poor resolution of the glutamate versus glutamine signal.Glutamate is present in all cell types with the largest pools evident in glutamatergic neurons; smaller pools are evident in GABA-ergic neurons and astroglia.

Upon release,astroglia convert glutamate to glutamine,which in turn is transferred back to the neuron for conversion once again to glutamate.Glutamine is primarily located in astroglia.Thus,low glutamate levels would be difficult to ascribe to a particular neuronal process.In contrast,if glutamine levels are low,then glial dysfunction may be present,a finding that would be consistent with white matter aberrations in marijuana users.Others have not reported specific metabolic disruptions in female marijuana users; indeed,within young samples,marijuana is more commonly used in males.Although it has been recognized that females are at an increased risk for some behavioral consequences of drug use such as sexual risk-taking and an increased risk of depression and anxiety following a pattern of daily marijuana use,sub irrigation cannabis there are relatively few human studies of brain-based sex differences associated with marijuana.McQueeny et al.showed adolescent girls had larger amygdalae and increased internalizing symptoms when compared to both control and marijuana using boys.Moreover,certain behavioral problems have also been linked to prenatal marijuana exposure in girls,but not in boys.Recent neuroimaging work suggests that young female users may be vulnerable to marijuana-induced alterations in brain volume,given suggestions of greater prefrontal cortex volumes and relatively poorer levels of executive function.Alcohol is similarly disruptive to females’ cognitive function and regional brain morphology,and it has long been recognized that females are more vulnerable to psychomotor sensitization with psychostimulant exposure.Preclinical data are somewhat stronger and indicate that female adolescents are particularly vulnerable to the effects of long-term THC administration on the CB1 receptor system in multiple brain regions,including the prefrontal cortex,striatum,and periaqueductal gray.A recent study of THC in mid-adolescent rats during the period of drug administration and following abstinence indicated greater sensitization of THC-induced locomotor depression in females versus males.Moreover,high doses resulted in increased anxiety-like behaviors during THC administration,particularly in females,although a general tendency is for females to experience greater anxiolytic effects of the drug.Glutamate is critically important in the neuroplasticity that accompanies the transition from drug use to abuse.Under conditions of extreme trauma or stress,its release is associated with neurotoxicity and cell death.Endocannabinoids block glutamate release under such conditions,which could lead to neuroprotection.However,the concomitant observation of high mIns levels argues against this interpretation.Given that mIns is considered to be a glial marker,high levels would be associated with gliosis as well as white matter injury as occurs in the context of neural injury.High mIns concentrations have been observed in early dementia,in frank Alzheimer’s disease,as well as in abstinent methamphetamine users,although this latter observation was in the frontal lobes.This pattern is intriguing given that deficits in learning and memory represent one of the robust areas of reported cognitive dysfunction in marijuana users.Although our data analyses do not suggest that female marijuana users in this sample are more vulnerable to cognitive impairments,this is a relatively young and high functioning sample.It may be that frank behavioral deficits will emerge more strongly in females over time as chronicity of use progresses.We hypothesize,too,that we may have observed altered NAA levels had we also measured frontal concentrations of each metabolite.Even though our statistical analyses do not show any significant effect of alcohol,it is important to consider the possibility of an underlying biological interaction between the two substances.Male marijuana users in this study had the highest levels of alcohol use,but did not show significant neurochemical alterations relative to controls.

Females showed the greatest apparent impact of marijuana use on Glx and mIns,but in the context of lower levels of alcohol use.These findings could suggest a neuroprotective effect in individuals who use both marijuana and alochol,as described by others.Alternatively,previous work has shown greater levels of Glx in the anterior cingulate of chronic alcohol users relative to controls.Considering this,taken together with the findings of the present study,it is possible use of the two substances together may drive metabolite concentrations to “normal” levels via opposing processes,as has also been suggested by others in the context of brain morphology.Differences in metabolic function in heavier versus lighter alcohol users can also impact the conversion of acetate into glutamate.It is possible,then,that the male marijuana users in this study who were heavier alcohol users as compared to females,demonstrated differences in glutamate metabolism,contributing to the observed sex difference.However this assertion is only speculative.While our data do not fully support these conclusions,the issue of alcohol use in the context of marijuana use requires careful examination in future studies.Sex but not group-related effects were also observed in total choline estimated concentrations.Independent of marijuana use,males showed higher estimated concentrations of tCho compared to females.

Posted in hemp grow | Tagged , , | Comments Off on Women have shown slightly more severe neurocogntive deficits related to marijuana use compared to men

Diet can affect risk factors shared by both cardiovascular disease and vasculogenic ED

In the PYS dataset,we combined parent and child information on child predictor variables to obtain a best estimate of the child behavior.For example,a behavior was counted when either the parent or child reported the behavior.Item scores were recoded as “Yes” or “No” where necessary to make them uniform across studies.For example,the Child Behavior Checklist [CBCL] has response options of 0,1 or 2 then item scores were recoded as Yes or No.We undertook separate analyses for each gender.We first determined which items were predictive of the outcome.We next summed significant items into an index,examined AUC,and computed sensitivity,specificity,and positive predictive power for the summary screening score.If the variance accounted for by these indicators proved too low,we repeated the procedure for “new items”.In the final analyses,three of the studies used CBCL items,and one study used data based on self-reported antisocial behavior,MFQ,and the Child Symptom Inventory.The items from the CBCL,the MFQ,and the CSI were highly comparable.The intercorrelation results of the predictor items showed that some items were significantly negatively correlated with the outcome variable,and other items correlated with the outcome non-significantly across all three datasets.This reduced the number of viable items in the Pittsburgh datasets to 14.The Michigan group derived their own scale of 9 items.In brief,a procedure very similar to that described here for the three Pittsburgh datasets was used.We intercorrelated available predictor variables that overlapped with those originally identified across externalizing,hyperactivity/impulsivity,internalizing,and temperament items with the outcome variable.This method was used to reduce the item pool,based on predictive accuracy.An intermediate,reduced set of items considered in the subsequent analyses are presented in Table 2.In prediction analyses with early-onset marijuana use as the outcome,the most predictive items were three externalizing characteristics: destroys things belonging to his/her family or others,steals outside the home,growers equipment and lying or cheating.We used these items to construct a preliminary 3-item scale.

We the determined whether we could improve upon this 3-item scale by adding each of the intermediate sets of individual items.The greatest improvement was seen with the addition of “disobedient at school”.The addition of parent smoking also improved the prediction results in all data sets.Table 3 compares the performance of this “5-item Screener” across both the construction and validation datasets.Considerable replication of results was shown across the nine analyses.Eight of the nine AUCs showed statistically significant findings.The AUCs were moderately strong,ranging from 0.59 to 0.74.In most instances,the AUC reduction from construction to validation analyses was low in magnitude.However,in the case of the PYS boys,the validation sample result was a non-significant finding.Table 3 shows that across all analyses,almost all the results held equally well for boys and girls.The proposed cut-off score of the 5-item Screener was selected based on balancing sensitivity and specificity.The resulting categorization of youth at high risk for early-onset marijuana use was based on the best possible sensitivity and specificity according to the performed AUC analyses.Table 3 reports the sensitivity and specificity across the nine analyses,which varied somewhat across the data sets.The results show that the optimal cut-off score in 4 out of the 9 analyses is 1.5 or 1.6,and.5 in another set of 4 analyses.Thus,a score of 1 or 2 on the screener optimally identified children at high risk for early-onset marijuana use.Table 4 shows the more detailed results of the analyses with information about sensitivity,specificity,PPV,NPV,and overall accuracy for 5-item Screener scores.We interpret these results as indicating that a threshold or “cut off” score of 2 or more would provide acceptable results.To further address whether internalizing items would enhance the accuracy of the 5-item Screener for predicting early-onset marijuana use,results with a scale including the 5-item Screener and two added internalizing items are presented.A comparison between Tables 3 and 5 shows that the addition of internalizing behaviors did not systematically improve the AUC analysis results.The additional items resulted in marginally lower AUCs in six out of the nine analyses.Thus,the addition of internalizing items failed to improve the 5-item Screener.Using the 5-item Screener,subsequent analyses were conducted to investigate the prediction of other substance use outcomes.Specifically,we investigated the extent to which the screener predicted alcohol use and illicit drug use at age 15 and older.Because of measurement limitations,the analyses only focused on the CEDAR and the MLS data sets.

The 5-item Screener applied to the CEDAR data set significantly predicted monthly alcohol use by the 15th birthday,illicit drug use by the 15th birthday,and the onset of a DSM-IV defined substance use disorder involving an illicit drug by the 18th birthday.We also examined two longer-term outcomes at an average age of 16.6 in the MLS data set.The 5-item Screener significantly predicted frequency of cigarette use in the past month,and frequency of problems associated with drinking in the past year.Thus,these results held for both and girls.Lastly,we examined in the CEDAR data set whether the inclusion of two internalizing items improved the prediction when added to the 5-item Screener on the longer-term outcomes.The results show that the inclusion of internalizing items did not improve predictions when added to the 5-item Screener and,instead,slightly reduced the AUC.s the legalization of cannabis continues to be liberalized for medicinal and recreational purposes,its consumption is expected to continue to rise.As of 2020,cannabis has been legalized in 33 states for medicinal purposes and in 11 states for recreational use.Yet,its distribution and use remain largely unregulated.According to the 2015 National Survey on Drug Use and Health in the United States,approximately 22.2 million Americans aged 12 and older reported current marijuana use within the past month,with a predominant prevalence of use in males between the ages of 18 and 25 years old.Research on cannabis both as medical therapy and on its adverse health effects is still nascent.Findings on the effects of cannabis use on male sexual health appear paradoxical.While enhanced sexual arousal and experience have been reported in some cannabis users,habitual cannabis use has been linked to erectile dysfunction.In one study,chronic cannabis smokers demonstrated penile vasculopathy on veno-occlusive plethysmography.With studies suggesting potential adverse effects on erectile function,the impact of cannabis on ED requires further investigation.An explanation for the paradox between the reported enhancement in sexual experience and impairment in erectile function with cannabis use may be attributed to the ubiquity of endocannabinoid receptors,cannabinoid receptor type 1 and type 2,throughout the body.

Cannabinoids,such as cannabidiol and THC,modulate the activity of dopaminergic and oxytocinergic neurons via brain CB1 receptors involved in the regulation of pleasure responses and sexual arousal.Findings of vasculogenic ED associated with cannabis use may be due to the activation of CB1 and CB2 receptors in the peripheral vasculature,which has been found to promote atherogenesis and endothelial dysfunction.The dried flower and leaves of Cannabis sativa,one of the most commonly consumed cannabis strains,contains over 100 pharmacologically active cannabinoids with different potential therapeutic properties and side effects.However,as the cannabinoid compositions in the different strains of cannabis are not standardized,the elicited physiological effects may be unpredictable as well.While purified THC has been studied for clinical use,investigations on marijuana,or Cannabis sativa,plant extracts for medicinal use may be more challenging due to the varying cannabinoid constituents.The Western dietary pattern,which is high in saturated fats and simple carbohydrates,has been associated with chronic systemic inflammation and the development of risk factors such as hypertension,obesity,and dyslipidemia found in vascular disease.Furthermore,in rodent models,a high-fat diet has been found to induce changes within the corpora cavernosa suggestive of vasculogenic ED.These adverse effects may likely be due to the generation of increased reactive oxygen species from the lipid-laden contents in an HFD.In a saturated endogenous anti-oxidant system,a redox imbalance can occur,leading to an increase in oxidative stress that results in the deleterious endothelial changes observed in vascular dysfunction.Although the relationship between cannabis consumption and metabolic conditions such as diabetes and dyslipidemia has not been established,cannabis use has been linked to high caloric intake and cardiovascular dysfunction.Thus,findings that suggest cannabis use and Western diet can negatively impact cardiovascular health may also imply possible harmful effects on erectile function as well.Thus,it is vital to determine whether the combination of diet and cannabis use may have an additive or synergistic effect on erectile tissue health.This study seeks to investigate the effects of HFD and the addition of either MJ or purified THC extract on the erectile tissue of mice.

Given that MJ extract contains a mixture of different cannabinoids of uncertain biochemical consequence compared to purified THC,we hypothesize that MJ extract may enhance the inflammatory process brought on by an HFD and lead to observable deleterious changes within the corpora cavernosa.Our results demonstrate that the development of fibrosis appeared most pronounced in the corpora cavernosa of mice given an HFD combined with oral MJ as evidenced by a decrease in SMC to collagen ratio,an increase in myofibroblast proliferation in the tunica albuginea,plant benches and a reduction in anti-oxidative stress expression.These findings suggest that in the setting of chronic HFD,the addition of MJ consumption may synergistically enhance inflammation and hasten penile fibrosis.In contrast to the effect of MJ extract,the addition of purified THC extract did not appear to exacerbate fibrotic changes.THC may mitigate the inflammatory response,which correlates with the benign impact that is found in the mouse corpora cavernosa of this study.The histological changes seen within the corpora cavernosa of mice fed HFD þ MJ are similar to alterations seen in both vascular atherosclerotic changes and cavernosal venoocclusive dysfunction.Whether brought on by chronic insults from smoking,diabetes,or obesity in vascular atherosclerosis or the aging process in corporal veno-occlusive dysfunction,a persistent inflammatory state triggers the apoptosis of SMCs and accumulation of collagen.In the penis,these findings are consistent with the progression of fibrosis associated with ED.Previous investigations alluding that the dysregulation of CB1 and CB2 receptors can result in atherosclerotic plaque formation in the peripheral vasculature provide insight into the corpora cavernosa histopathology of mice treated with HFD þ MJ.Activation of CB1 receptors can lead to the production of lipid-laden macrophages and reactive oxygen species.While antagonism of CB2 receptors found in immunomodulatory cells can dampen the recruitment of proinflammatory cytokines and myofibroblasts,agonism of CB2 receptors in the corpora cavernosa may reduce reactive oxygen species.The cascade of events brought on by CB1 and CB2 receptor modulation results in the plaque formation seen in vascular endothelium injury,remodeling,and eventual fibrosis.These mechanisms may also be at play in the fibrosis observed in the corpora cavernosa of mice fed HFD þ MJ in this study.The increase in fibroblast to myofibroblast transition in the connective tissue of the tunica albuginea and the accompanying decrease in cavernosal SMC to collagen ratio was significant in the HFD þ MJ group.MJ,the extract of Cannabis sativa used in this experiment,contains a multitude of natural cannabinoid constituents.This may have led to the non-specific binding of the unidentified constituents to the endocannabinoid receptors,resulting in the activation of the inflammatory cascade and leading to the increased myofibroblast expression.This increase also suggests that MJ may exacerbate the fibrotic progression already underway within the corpora cavernosa oxidative stress already brought on by HFD.Previous studies using animal models suggest that THC may have anti-inflammatory and anti-oxidative properties,presumably via CB2 receptor interaction.

THC has been shown to slow the disease progression in rodents induced with rheumatoid arthritis,atherosclerotic plaques,and hepatic fibrosis.In line with these studies,in this experiment,the corpora cavernosa of mice given a diet and THC extract did not demonstrate as a significant reduction in HO-1 expression as in those given a diet and MJ extract.This finding may explain the lack of architectural changes found in the corpora cavernosa of mice administered either NCD þ THC or HFD þ THC.The reduction in oxidative stress and minimal adverse tissue changes suggest the therapeutic potential of THC as an antioxidant,although more studies are needed.Furthermore,while it appears that purified THC can exert anti-inflammatory and anti-oxidative effects applicable for clinical use,caution may be needed with the use of whole cannabis plant extract in which the cannabinoid constituents are unidentified and unquantified,such as with MJ in this experiment.As the legalization of cannabis continues to expand for medicinal treatment and recreational use,further delineation of the beneficial and detrimental properties of cannabinoids and their CB1 or CB2 receptor proclivities is warranted.Additionally,with respect to male sexual health,identifying the presence and localization of endocannabinoid receptors within the corpora cavernosa may further elucidate the effects of cannabis and its components.

Posted in hemp grow | Tagged , , | Comments Off on Diet can affect risk factors shared by both cardiovascular disease and vasculogenic ED

Regional volume vulnerabilities may increase risk for initiation and maintenance of marijuana misuse

The comorbid use of alcohol and marijuana among teens continues to subtly rise asperception of harm declines.Fifty-eight percent of alcohol drinking adolescents report using alcohol and marijuana simultaneously,45% of youth endorse a lifetime prevalence of marijuana use by the 12th grade,and 22% of these youth endorse use in the past 30 days.The adolescent brain undergoes considerable maturation,including changes in cortical volume and refinement of cortical connections.These neural transformations leave the adolescent brain more susceptible to potential neurotoxic effects of substances.Although overall brain volume remains largely unchanged after puberty,ongoing synaptic refinement and myelination results in reduced gray matter and increased white matter volume by late adolescence.Cortical gray matter follows an inverted U-shaped developmental course,with cortical volume peaking around ages 12–14.The mechanisms underlying the decline in cortical volume and thickness are suggested to involve pruning and elimination of weaker synaptic connections,decreases in neuropil,increases in intra-cortical myelination,or changes in the cellular organization of the cerebral cortex.In contrast,white matter development generally is characterized by linear volume increases driven by progressive axonal myelination.These processes refifine motor functioning,higher-order cognition,and cognitive control.Studies show alterations in white matter integrity in adolescent marijuana users compared to non-users,particularly in fronto-parietal circuitry and pathways connecting the frontal and temporal lobes.Altered cortical morphometry has also been observed in adolescent marijuana users,with marijuana-using adolescents having larger cerebellar volumes than non-users,thinner cortices in prefrontal and insular regions,and thicker cortices in posterior regions when compared to controls.Structural neuroimaging studies have also examined whether structural brain alterations were present before onset of marijuana use.Notably,cannabis square pot orbitofrontal cortex volumes at age 12 predicted initiation of marijuana use at age 16 when controlling for other substance use.

This study builds on previous work by our laboratory examining the acute and longer-term impact of adolescent marijuana use on cortical thickness pre- and post 28-days of monitored abstinence from marijuana.We found increased temporal lobe thickness estimates in adolescent heavy marijuana users,and negative associations with cortical thickness and lifetime marijuana use both acutely and following prolonged abstinence from marijuana.It is unclear if such structural alterations of the cerebral cortex persist into young adulthood.The aim of this prospective study was to identify differences in cortical thickness between adolescent heavy marijuana users and control adolescents with minimal substance use histories assessed at three independent time points.We hypothesized that those individuals who initiated heavy marijuana use during adolescence would show thicker cortices over time compared to our control teens by young adulthood in frontal and temporal brain regions.Adolescents were recruited from local San Diego schools and followed for three years,which included a baseline assessment and subsequent 1.5,and 3-year in-person follow-up visit.Participants underwent neuro imaging and substance use assessment at all three time points.Study design invited individuals back every 18-months in order to capture relationships between substance use and neuro imaging estimates spanning adolescence to young adulthood.Inclusion in the present study required valid neuro imaging data at all three time points to avoid asymmetrical processing in the longitudinal cortical thickness processing approach.All participants underwent written informed consent in accordance with the University of California,San Diego Human Research Protections Program.Marijuana and control groups were selected based on lifetime marijuana use episodes at baseline,and alcohol use was limited to <150 lifetime drinking episodes for both groups at enrollment.Average days of marijuana use per month ranged from 13 to 15 days over the course of three years for the substance users.The vast majority of substance users,MJ +ALC,met criteria for marijuana abuse/dependence over the course of the three-year study and approximately 87% met criteria for alcohol abuse/dependence.Approximately 55% of controls met criteria for alcohol abuse/dependence over the course of the study; six participants in the control group met abuse criteria for marijuana use at 3-year follow-up.

See Fig.1 for frequency and cumulative alcohol and marijuana use reported over the course of three years for the sample.Exclusionary criteria at study entry included: history of a lifetime DSM-IV Axis I disorder,history of learning disability; history of neurological disorder or traumatic brain injury with loss of consciousness >2 min; history of a serious physical health problem; complicated or premature birth including prenatal substance use; uncorrectable sensory impairments; left handedness; and use of psychoactive medications.Participants underwent weekly toxicology screening for four weeks prior to their neuro imaging session to confirm abstinence from marijuana at each time point.Decreasing 11-nor-9-carboxytetrahydrocannabinol metabolite ratios confirmed completion of the marijuana abstinence protocol at each visit and helped ensure the longer-term adverse alterations in cortical thickness were being captured,as compared to acute effects of recent use.Compliance at each visit was determined for each positive test result by dividing each THCCOOH normalized collection by the previous collected specimen,per Huestis and Cone recommendations for determining new cannabis use as a function of time.Notably,positive THCCOOH/creatinine ratios ranged from 0.0 to 10.6 ng/mg on the day of the scan session across all three time points,which falls below the commonly used confirmation cutoff <15 ng/mL.The Diagnostic Interview Schedule for Children Predictive Scales was administered to youth and parent at the screening interview to identify and exclude those individuals with Axis-I disorders other than alcohol or cannabis use disorder.The Beck Depression Inventory and Spielberger State Trait Anxiety Inventory assessed depression and state anxiety.The Family History Assessment Module assessed family history of psychiatric and substance use disorders.Parental income and grade point average were collected during a clinical interview prior to the baseline imaging session.The Wechsler Abbreviated Scale of Intelligence Vocabulary subtest was included as an estimate of premorbid intellectual functioning.All scans were acquired on the same 3.0 T CXK4 short bore Excite-2 magnetic resonance system with an eight-channel phase array head coil at the University of California San Diego Center for Functional MRI.Subjects were asked to remain still in the scanner while a high-resolution T1-weighted anatomical spoiled gradient recall scan was acquired.Cortical thickness estimates were extracted using previously published methods by our laboratory.The neuroimaging software FreeSurfer,which is well documented and freely available,was used for cortical surface reconstruction and thickness estimates.

The initial cross-sectional process involves motion correction and averaging of T1 weighted images,removal of non-brain tissue and transformation to standardized space,segmentation of sub-cortical white and deep gray matter structures,intensity normalization,and tessellation of the gray/white matter boundary.Local MRI intensity gradients then guide a surface deformation algorithm to place smooth borders where the greatest shift in intensity defines transition to other tissue classes ; this procedure allows for quantification of sub-millimeter group differences.Cortical thickness was calculated as the closest distance from the gray/white matter boundary to the gray matter/cerebral spinal fluid boundary at each vertex on the cortical surface.Validity of the cortical thickness measurement procedures has been verified using manual measurements and histological analysis.Test–retest reliability across scanners and field strenghts has been shown using these standardized procedures.Following cross-sectional processing of all three time points,data was next fed through the longitudinal processing stream in Free Surfer.This approach extracts reliable volume and thickness estimates by creating an unbiased within-subject template space and image from the three cross sectionally processed time points using a consistent robust inverse registration method.Processing steps such as Talairach transforms,atlas registration,and spherical surface maps and parcellations are initialized with common information from the within-subject template,increasing reliability and statistical power.To identify errors made during cortical reconstruction processing,one rater,blind to participant characteristics,followed the reconstruction and longitudinal edit procedures to correct any errors made during the cortical reconstruction process.This involved verification of the automated skull stripping,and a coronal plane slice-by-slice inspection of the gray/white and gray/cerebral spinal fluid surfaces.Modifications to the surfaces were made as necessary to correct for tissue misclassifications.All longitudinal runs were checked for quality,and no editing was necessary following the longitudinal processing.Following inspection,an automated parcellation procedure divided each hemisphere into 34 independent cortical regions based on gyral and sulcal features.Cortical thickness estimates averaged over each parcellation region were extracted for statistical analyses in SPSS.Repeated measures analysis of covariance examined main effects of group,time,and Group by Time interactions on cortical thickness values for 34 independent standard neuroanatomical cortical regions in each hemisphere.significant between-group and interaction effects were followed-up post hoc to determine what time point was driving the statistically significant between-group differences.Intracranial volume and lifetime alcohol use was included as a covariate given the high rate of alcohol use reported by the marijuana users in this sample.This study looked at cortical thickness estimates at three independent time points in adolescent marijuana and alcohol users compared to controls with limited substance use histories.

We found significant between group differences in cortical thickness estimates after controlling for lifetime alcohol use.MJ +ALC demonstrated increased cortical thickness estimates in all four lobes of the brain,bilaterally.Notably,18 of 23 regions in which differences were observed were in the frontal and parietal cortex.Positive dose-dependent associations were identified in temporal brain regions,trim tray as cumulative marijuana use from ages 16 to 22 was associated with thicker cortices in inferior temporal and entorhinal cortex.Several negative associations were observed with lifetime alcohol use,as more alcohol use reported was associated with thinner cortical estimates in all four lobes.It is important to detail how these findings compare to our previous work with a similar sample,as we found both similarities and differences from our cortical thickness study in which adolescent marijuana users were observed pre- and post 28-days of monitored abstinence.In Jacobus et al.,increased thickness estimates in our marijuana users was found in the entorhinal cortex compared to matched controls.Similarly,the present study found increased thickness estimates in our user group compared to our controls,and findings were more widespread and noted in all four lobes of the brain.The present study also found more lifetime marijuana use was associated with increased thickness in the entorhinal cortex,a region rich in cannabinoid 1 receptors and important for learning and memory.However,dose-dependent bivariate correlations were different in that previously we saw increased marijuana use associated with thinner cortices and increased alcohol use associated with thicker cortical estimates at age 17,pre- and post monitored abstinence.Our dose-dependent associations in the present study suggest otherwise.We found increased lifetime marijuana use reported associated with thicker cortical estimates and increased lifetime alcohol use reported associated with thinner cortices.This may reflect several points recently discussed by Filbey and colleagues in the literature,including methodological issues,the present study assessed substance independently over the course of three years compared to 28-days at age 17; age and maturational bias,correlations in the present study reflect associations following many years of substance use and potential for interference with complex neuro developmental processes; changes in marijuana and alcohol use patterns,as individuals in the present study remain relatively chronic in their marijuana use over time but subtly increase in their alcohol use; and possible interactions with pre-existing vulnerabilities that are present at age 17,but likely changes as the individual continues to chronically use substances and increase in age Lopez-Larson and colleagues cross-sectionally investigated cortical thickness in adolescents ages 16–19 years,with heavy marijuana use histories.They found decreased thickness in frontal regions and the insula,along with increased thickness in lingual,temporal,and parietal regions.The present study found increases in thickness in parietal,temporal,and occipital cortices,consistent with work by this team.The mechanism by which marijuana may alter the neural architecture and plasticity of the brain is undetermined.The endocannabinoid system plays a role in neuromaturational processes and modulates neurotransmission for several neurotransmitter systems.Interference with this system due to marijuana,or tetrahydrocannabinol administration,likely causes a cascade of neuronal events that changes brain structure and function,and thereby neurocognitive processing,emotional regulation and reward processing,and propensity for psychiatric comorbidities and addiction.It is unclear how associations with marijuana use and cortical thickness remodeling may be unique compared to alterations in macrostructural volume.Studies suggest that volume changes are driven by changes in surface area whereas others suggest thickness as one ages,however relationships between these metrics are likely dynamic across the lifespan and represent different neuromaturational mechanisms at different stages of life and disease.Changes in regional brain volume associated with marijuana use have varied,as some have observed decreased volume and others have identified macrostructural volume increases in CB1-dense brain regions such as neocortex,amygdala,striatum,hippocampus,and cerebellum.In reward-network regions specifically,such as the orbitofrontal cortex,a recent examination by Filbey and colleauges,found decreased orbitofrontal cortex volume in heavy marijuana users compared to controls,and increased structural and functional connectivity within the OFC network.Lorenzetti and collages,did not find OFC differences in their sample of heavy marijuana users,but did see smaller hippocampus and amygdala volumes.Cheetham et al.found that smaller OFC volume pre-initiation of marijuana use predicted progression into use four years later.

Posted in hemp grow | Tagged , , | Comments Off on Regional volume vulnerabilities may increase risk for initiation and maintenance of marijuana misuse

Mechanisms of moisture transport in a single porous building material have been extensively studied

A detailed parametric study of hygrothermal behaviour of a wall made of hemp concrete submitted to hygrothermal shock has been carried out and showed that temperature and relative humidity variations in a wall are very sensitive to thermal properties,moisture transport coefficient and sorption isotherm.Up to now,most hygrothermal tools have used the isothermal sorption curves that express the equilibrium between the moisture content and relative humidity in the representative elementary volume at a constant temperature.However,few works studied the effect of temperature on hygrothermal behaviour of building envelope.This article aims to study the effect of the temperature-dependent sorption on the prediction of hygrothermal behavior of a hemp building envelope submitted to a variation of temperature and relative humidity.First,the details for the mathematical model are shown.The models were elaborated and implemented in the Simulation Problem Analysis and Research Kernel,which is adapted to the complex problems.Then,the simulation tools are validated with experimental results obtained from the test wall realised in our laboratory.After being validated,the effect of non-isothermal conditions on the temperature and relative humidity profiles will be discussed.In the next part,the mathematical model for the coupled heat and moisture transfer in building materials will be presented.Most of the models have nearly the same origin; the main difference among them is related to particular assumptions used.In this article,the model that takes into account liquid and vapor moisture transport is used.Forms of moisture transport depend on the pore structure as well as on the environmental conditions.The liquid phase is transported by capillarity whereas the vapor phase is due to the gradients of partial vapour pressure.The comparison between the variation of temperature and relative humidity at point C obtained from the simulation using the Isoth model and the one from the experimental measurement is presented in Fig.2 and Fig.3.One can observe that the variation of temperature is very similar for the three studied cases.The model gives a quite satisfactory prediction of temperature within the wall,despite the underestimation of the maximum temperature and the overestimation of the minimum temperature.

Concerning the variation of relative humidity,cannabis grow racks the computed results did not fit to the experimental ones.This should be explained by the fact that the studied model neglected the effect of temperature on the moisture sorption capacity of the material,in which increasing temperature results in increase of the relative humidity at given water content.Therefore,the dependency of sorption characteristic on temperature has been taken into account in the physical model and the result will be presented in the following subsection.As mentioned in the subsection 2.2,both Milly’s model and Poyet’s model have been used to study the impact of non-isothermal conditions on the hygrothermal behavior of hemp concrete.Because the results obtained from the Milly’s model is very close to those from Isoth model,they are not depicted here.This subsection focuses only on the results obtained by using Poyet’s model and the comparison between its results and experimental data are shown in Fig.4 and Fig.5.As can be seen from Fig.4,the numerical results are in accordance to the experimental results.In addition,they are very close to those obtained by using the Isoth model.Fig.5 showed that compared to the final one,the Non-Isoth model results in significantly better prediction of the relative humidity variation in the tested wall.Concerning three cases studied,the results are dependent on which the sorption curve is used for the simulations.The results calculated with the adsorption allow a better prediction of the relative humidity variation than those for the model that uses an average sorption curve between adsorption and desorption or desorption curve.The maximum difference between the computed results for the model that uses adsorption curve and the experimental ones is 3% RH.This value is small compared to the accuracy of sensor inserted in the tested wall,which is ±1.5% of RH.The environmental impact of construction sector is increasing thus to satisfy the sustainable development criteria,new constructions need to recycling existing building construction materials or to use bio based materials which have low environmental impact.In this context the hygrothermal behavior of a real sized hemp concrete wall is studied in this paper.

Hemp based structural materials are more and more often used all over the world,especially in France,Great Britain or China,countries which have a long tradition of hemp cultivation.Since the eighties different research have been done on the hemp concrete.Now experimental and numerical studies are available from material scale studies to building scale analysis.Usually wall sized structure use a lime-hemp mixture.Here a blending of Prompt Natural Cement and the non-fibrous part of hemp,called shiv,was used and studied walls were exposed to weather conditions on the outside and controlled conditions on the inside.The PASSYS test cells were presented previously in.They were originally designed to test passive solar components under real weather conditions .Two of them,both located at CEA INES experiment platform in Le Bourget du Lac,south-eastern France,were used in the present experiment.They are 8.44m long,3.61m wide and 3.8m high.The cells are made of a metallic frame insulated by 48 cm of polystyrene and mineral wool to have 5 highly insulated,water and vapor proof walls.The 6th face is reserved for 3.6*3.3 m² sized testing façade here facing the South.Each cell is placed on a raised support which allows free air circulation around all sides and has a system to control indoor temperature and an independent system to control relative humidity.Indoor moisture generation is not limited in mass,generated quantities are recorded by a data logger connected to a balance on which an ultra-son moisture generator is placed.The studied wall was built in precast hemp concrete blocks system,made with Prompt Natural Cement,see Fig.1 with a concrete column.Heat bridge breaking insulation was applied around the whole structure while the outside coating covers all elements of the structure.The sensors position in the wall structure is presented in Fig.2.A vertical and two horizontal gradients,in depth and in width of the wall,are measured.Two kind of recorded data are reported here,temperature and relative humidity,heat flux measurements are not involved in this paper.

To measure RH,a capacitive sensor was used,which was protected by a manually added device in order to avoid the chemical attack of concrete on sensible element of the sensor head and the direct contact with liquid water.This method implies that we adopted the hypothesis that the sensor and its environment are in moisture equilibrium,thus recorded data is measured in air but considered in material.No weight measurement of moisture content is involved in this paper.3D behavior of the studied wall was analyzed.Measured data is presented in two section of the façade: concrete post zone and hempcrete blocks zone for a one year long period.In Fig.3.temperature profiles in both vertical sections are presented in both test cells on the outside and P4= PASSYS 4 covered with traditional lime-based coating on the outside.The data recording time step was one minute.On each part of the figure three heights are represented,bottom,middle and top of the wall as it was seen in Fig.2.Upper part shows the evolution of the temperature in the room air and under interior coating.These graphics puts in evidence that between indoor air and under inside coating only a small difference is perceived.Concerning vertical gradient,the discrepancies between the 3 heights are not significant,gap does not exceed 1°C.And it is valid for both test cells.Recorded data in the concrete post has,as expected,less variation.The curve is less perturbed by the rapid fluctuation of outdoor conditions.Nevertheless a slow seasonal variation is observable,as during winter period the concrete column temperature is lower than during the summer period,independently from indoor conditions.Outdoor temperature variation affects the measured data under outside coating independently from the presence or not of the concrete post behind as recorded data has the same variation in both presented sections.Initial conditions are the same at the three different heights.This similarity was kept during the one year measurement period.It suggests that the homogeneity boundary condition,that we supposed to be valid in the whole wall,is satisfied for temperature considerations.The same kind of presentation is following for relative humidity measurements.For a better understanding,one average data per day is printed in the figure.Fig.4.presents the two above mentioned vertical sections with always the three different horizontal cuts.The impact of initial boundary conditions is clearly seen in this figure.The intrinsic moisture content of hemp concrete influences the measured data during a period which lasts several months.The highest values were measured at the bottom of the wall while the lowest values were measured at the middle.The top section values are between the bottom and middle values.

One probable reason is the involuntary rain water leakage of the wall from outside during rainy periods.It could come from the experimental installation as the lower part of the wall was not protected against this kind of water infiltration.This effect was not measured separately and remains a suggestion.Another reason could be due to different initial moisture content,but after several month this effect was faded,cannabis grow system and moisture content varied in function of boundary conditions rather than in function of initial conditions.The different sensors converge to the same value in time which confirm the homogenous wall hypothesis which may be applied after an initial period only.This question was also studied numerically in the PASSYS 3 test cell and presented later on.A huge difference,up to 30% of RH,between the two test cells was observed.It is partly due to different initial moisture content and partly due to different outside coating even if both walls were oriented to South and they had received the same weather conditions.A parallel analysis showed that the traditional lime-based coating was more water permeable than the industrial coating,thus outside moisture is more absorbed by the coating of P4 than the coating of P3.The detailed analysis of the coatings is not the object of this paper.The 3D analysis shows that after the initializing period the differences between the 3 studied heights stay under 10%.This is corroborated by the center graphs of Fig.4.Once the initial conditions are no more important,the spatial moisture distribution in each studied wall can be considered as homogenous,except around the concrete post which has a slower drying kinetic as it is shown on the right side center graph of Fig.4.In general the presence of a slow drying process in the core of both walls is observed without reference to concrete block or column.In Fig.4.during the Decemberand January period,under the outside coating,RH values stayed around 100% in P4 while in P3 RH values progressed more in correlation to the rest of the wall than to the outside conditions.This important difference is induced by the outside coatings as it was mentioned above.The research team recently developed an innovative system with low environmental impact for the production of semi-rigid panels for thermal and acoustic insulation,obtained from recycled sheep’s wool,from Piemonte region.Starting from the previous work,a new semi-rigid panel was produced,where recycled sheep’s wool is combined with hemp technical fiber.Hemp cultivation presents huge benefits for soils in crops rotation environmental field: this culture easily adapts to different types of climate and high yields can be produced with relatively low resources; moreover it exerts a restorative action on soils,leaving a considerable amount of organic waste,which benefits the cultures that follows in the rotation crops,as stated by Assocanapa.Moreover the high annual biomass production,and its strong ability to absorb CO2 from atmosphere,hemp can be considered an interesting alternative source of energy valorization and biomass.Interest in building for hemp materials especially relies in its recyclability,hygroscopic,water vapor permeability and durability properties,its resistance to mold and fungus attacks and the porous characteristics of fibers and shives; as well as its low environmental impact and low cost.Hemp cultivation has deep roots in Italy,since medieval times,during Maritime Republics age when even in Piemonte region,particularly Carmagnola gradually became a renowned center in the production and diffusion of hemp in the region and abroad.Up to 1960 Italy was among the first countries in the world for planted area and quality of products.After a period following World War II in which hemp cultivation on our territory began gradually to disappear,it was re-introduced at the end of 1990s on a 350 ha area approximately; nowadays it is recovering importance thanks to the efforts of producers as Assocanapa and the recovered cooperation with industrial sectors on local short chain mechanism.Products obtained from hemp stalks processing are shives,fibers and dust.

Posted in hemp grow | Tagged , , | Comments Off on Mechanisms of moisture transport in a single porous building material have been extensively studied