Modelling Kinetics of Plant Canopy Architecture - Concepts and Applications

Most crop models simulate the crop canopy as an homogeneous medium. This approach enables modelling of mass and energy transfer through relatively simple equations, and is useful for understanding crop production. However, schematisation of an homogeneous medium cannot address the heterogeneous nature of canopies and interactions between plants or plant organs, and errors in calculation of light interception may occur. Moreover, conventional crop models do not describe plant organs before they are visible externally e.g young leaves of grasses. The conditions during early growth of individual organs are important determinants of final organ size, causing difficulties in incorporating effects of environmental stresses in such models. Limited accuracy in describing temporal source-sink relationships also contributes to difficulty in modelling dry matter distribution and paramaterisation of harvest indices. Functional-architectural modelling overcomes these limitations by (i) representing crops as populations of individual plants specified in three dimensions and (ii) by modelling whole plant growth and development from the behaviour of individual organs, based on sound models of organs such as leaves and internodes. Since individual plants consist of numerous organs, generic models of organ growth applicable across species are desirable. Consequently, we are studying the development of individual organs, and parameterising it in terms of environmental variables and plant characteristics. Models incorporating plant architecture are currently applied in education, using dynamic visual representation for teaching growth and development. In research, the 3D representation of plants addresses issues presented above and new applications including modelling of pesticide distribution, fungal spore dispersal through splashing and plant to plant heterogeneity

Binge Drinking: A Confused Concept and its Contemporary History

Binge drinking is a matter of current social, political and media concern. It has a long-term, but also a recent, history. This paper discusses the contemporary history of the concept of binge drinking. In recent years there have been significant changes in how binge drinking is defined and conceptualised. Going on a ‘binge’ used to mean an extended period (days) of heavy drinking, while now it generally refers to a single drinking session leading to intoxication. We argue that the definitional change is related to the shifts in the focus of alcohol policy and alcohol science, in particular in the last two decades, and also in the role of the dominant interest groups. The paper is a case study in the relationship between science and policy. We explore key themes, raise questions and point to a possible agenda for future research

Improved Quality of Life Following Addiction Treatment Is Associated with Reductions in Substance Use

People seeking treatment for substance use disorders (SUD) ultimately aspire to improve their quality of life (QOL) through reducing or ceasing their substance use, however the association between these treatment outcomes has received scant research attention. In a prospective, multi-site treatment outcome study (‘Patient Pathways’), we recruited 796 clients within one month of intake from 21 publicly funded addiction treatment services in two Australian states, 555 (70%) of whom were followed-up 12 months later. We measured QOL at baseline and follow-up using the WHOQOL-BREF (physical, psychological, social and environmental domains) and determined rates of “SUD treatment success” (past-month abstinence or a statistically reliable reduction in substance use) at follow-up. Mixed effects linear regression analyses indicated that people who achieved SUD treatment success also achieved significantly greater improvements in QOL, relative to treatment non-responders (all four domains p 0.001). Paired t-tests indicated that non-responders significantly improved their social (p = 0.007) and environmental (p = 0.033) QOL; however, their psychological (p = 0.088) and physical (p = 0.841) QOL did not significantly improve. The findings indicate that following treatment, QOL improved in at least some domains, but that reduced substance use was associated with both stronger and broader improvements in QOL. Addressing physical and psychological co-morbidities during treatment may facilitate reductions in substance use

Terahertz spectroscopy of spin excitations in magnetoelectric LiFePO4 in high magnetic fields

Contains fulltext : 283891.pdf (Publisher’s version ) (Open Access

SrCu_2(BO_3)_2 - a Two Dimensional Spin Liquid

We study an extended Shastry-Sutherland model for SrCu_2(BO_3)_2 and analyze the low lying parts of the energy spectrum by means of a perturbative unitary transformation based on flow equations. The derivation of the 1-magnon dispersion (elementary triplets) is discussed. Additionally, we give a quantitative description (symmetries and energies) of bound states made from two elementary triplets. Our high order results allow to fix the model parameters for SrCu_2(BO_3)_2 precisely: J_1=6.16(10)meV, x:=J_2/J_1=0.603(3), J_\perp=1.3(2)meV. To our knowledge this is the first quantitative treatment of bound states in a true 2d model.Comment: 4 pages, 3 figures, Proceeding paper of the HFM2000 conference in Waterloo, Canada, Jun 200

Characteristics of individuals presenting to treatment for primary alcohol problems versus other drug problems in the Australian patient pathways study

Background: People seeking treatment for substance use disorders often have additional health and social issues. Although individuals presenting with alcohol as the primary drug of concern (PDOC) account for nearly half of all treatment episodes to the Australian alcohol and other drug (AOD) service system, previous treatment cohort studies have focused only on the profile of Australian heroin or methamphetamine users. While studies overseas indicate that clients seeking treatment primarily for their drinking are less likely to experience social and economic marginalisation than those seeking treatment primarily for illicit or pharmaceutical drug use, very little research has directly compared individuals presenting with alcohol as the PDOC to those primarily presenting with other drugs as their PDOC. Methods: Seven hundred and ninety-six participants were recruited at entry to specialist AOD treatment in Victoria and Western Australia, and completed measures of demographic and social factors, substance use, quality of life, service use, and criminal justice involvement. We compared those with alcohol as their PDOC to those with other drugs as their PDOC using Pearson chi-square and Mann–Whitney U tests. Results: Rates of social disadvantage, poor quality of life, high severity of substance dependence, and past-year AOD, mental health, acute health, and social service use were high in all groups. However, participants with alcohol as the PDOC were older; more likely to have an educational qualification; less likely to report criminal justice involvement, housing/homelessness service use, tobacco smoking, or problems with multiple substances; and reported better environmental quality of life; but were more likely to have used ambulance services, than those with other drugs as their PDOC. Conclusions: While those seeking treatment primarily for alcohol problems appear less likely to suffer some forms of social and economic disadvantage or to use multiple substances than those with a primary drug problem, they experience similarly high levels of substance dependence severity and mental health and AOD service use. These findings reinforce the need for AOD services to integrate or coordinate care with programs that address the many complexities clients frequently present with, while also acknowledging differences between those seeking treatment for alcohol versus other drug problems

A Thousand Contradictory Ways: Addiction, Neuroscience, and Expert Autobiography

Neuroscientific accounts of addiction are increasingly influential in health and medical circles. At the same time a diverse, if equally scientifically focused, opposition to addiction neuroscience is emerging. In this struggle over the merits of addiction neuroscience are elements of a uniquely 21st-century public engagement with science. No longer trusted by the public as the unerring source of objective knowledge about the world, science is, at least in some contexts, increasingly treated as just one voice among many. Observing the difficulties this loss of faith in science poses for effective action on pressing issues such as climate change, philosopher Bruno Latour develops a different (ecological) approach to scientific knowledge, one that for the first time allows scientists (and other “moderns”) to understand it for what it really is and locate it “diplomatically” alongside other modes of knowing. In this article, I ask whether a similar innovation is needed to allow more effective understanding of addiction. I explore this question by analyzing two recent, widely discussed, popular books (Marc Lewis’s Memoirs of an Addicted Brain: A Neuroscientist Examines His Former Life on Drugs, 2011 and Carl Hart’s High Price: A Neuroscientist’s Journey of Self-discovery that Challenges Everything You Think You Know About Drugs and Society, 2013) as well as reviews of these books. Written by neuroscientists, and drawing heavily on personal memoir to illustrate and ratify their competing views on drugs and addiction, both books crystallize contemporary dilemmas about science, empiricism, and the nature of evidence and truth. How are we to understand their mix of “scientific fact” and individual self-observation, what does this mix suggest about scientific knowledge, and what are its implications for dominant notions of “evidence-based” drug policy and treatment? I argue that these books both trouble and reinforce our taken-for-granted distinctions between science and personal stories, between objectivity and subjectivity, and note the lost opportunities the books represent for a more searching and productive (Latour might say “ecological”) engagement with science

Reconstructing ‘the Alcoholic’: Recovering from Alcohol Addiction and the Stigma this Entails

Public perception of alcohol addiction is frequently negative, whilst an important part of recovery is the construction of a positive sense of self. In order to explore how this might be achieved, we investigated how those who self-identify as in recovery from alcohol problems view themselves and their difficulties with alcohol and how they make sense of others’ responses to their addiction. Semi-structured interviews with six individuals who had been in recovery between 5 and 35 years and in contact with Alcoholics Anonymous were analysed using Interpretative Phenomenological Analysis. The participants were acutely aware of stigmatising images of ‘alcoholics’ and described having struggled with a considerable dilemma in accepting this identity themselves. However, to some extent they were able to resist stigma by conceiving of an ‘aware alcoholic self’ which was divorced from their previously unaware self and formed the basis for a new more knowing and valued identity

Beer, wine and distilled spirits in Ontario: A comparison of recent policies, regulations and practices

AIMS: There is a long-standing discussion about whether some beverages are more likely to be linked with high-risk drinking and damage than others, and implications for beverage specific alcohol policies. While the evidence is inconclusive, when controlling for individual consumption, some studies have shown elevated risks by beverage type. This paper examines the situation in Ontario, Canada, from 1995 to present (2011) on several dimensions in order to assess the differences by beverage and their rationale with a specific focus on the most recent policies. METHODS: This paper draws on archival consumption statistics, taxation and pricing arrangements, and retailing and marketing practices. RESULTS: Off-premise sales, which represent an estimated 75% of ethanol, involve several channels: stores controlled by the Liquor Control Board (LCBO) - which sell all spirits, imported and domestic wines, and beer products; the Beer Store network which sell all beers; and Ontario winery stores - which sell Ontario wines. In LCBO stores Ontario wines are more prominently displayed than other beverages, and extensive print advertising tends to feature wine over beer and spirits. There are also differences by beverage in terms of taxation and price. The taxes on higher alcohol content beverage types account for a higher portion of the retail price than taxes on lower alcohol content beverage types. Furthermore, minimum price regulations allow for differential minimum pricing per standard drink [17.05 ml ethanol] across beverage types. CONCLUSIONS: The apparent rationale for these arrangements is not primarily that of favouring lighter-strength beverages in order to reduce harm, but rather to accommodate long-standing vested interests which are primarily financially based