The Social Contagion Effect of Marijuana Use among Adolescents

Research on adolescent substance use has consistently identified a strong relationship between adolescent behavior and the behavior of their peers. However, peer effects are difficult to estimate and causal interpretations must be undertaken with caution since individuals in most cases choose with whom to associate. In this paper we seek to empirically quantify the causal role of peer social networks in explaining marijuana usage among adolescents.Using data from a nationally representative sample of adolescents we utilize a multivariate structural model with school-level fixed effects to account for the problems of contextual effects, correlated effects and peer selections to purge the potential biases from the estimates of peer influence. Our peer group measures are drawn not only from the nomination of close friends (N = 6,377), but also from classmates (N = 19,335). Marijuana usage among the peer groups were constructed using the peers' own report of their marijuana consumption. Controlling for parent level characteristics, and other demographic parameters, we find that a 10% increase in the proportion of close friends and classmates who use marijuana increases the probability that an individual chooses to use marijuana by 5%.Our findings indicate that peer effects are important determinants of marijuana use even after controlling for potential biases We also found evidence to show that the influence of close friends and the more exogenous classmates are quite similar in magnitude under our preferred specification, supporting theory predicting the importance of peer influence. Effective policy aimed at reducing marijuana usage among adolescents would consider these significant peer effects

The Leader programme 2007-2013: Enabling or disabling social innovation and neo-endogenous development? Insights from Austria and Ireland

Since the beginning of the 1990s, the Leader programme has been hailed as the instrument of rural policy that most explicitly takes account of the territorial dimension. This culminated in the mainstreaming of its underlying concept into the Rural Development Programmes of the current period (2007–2013), with the aim of having more effective policy implementation that considers the diversified needs of rural regions. Starting from analysis of the application and delivery of Leader under the present Rural Development Programme in two EU countries, Austria and Ireland, this paper presents an assessment of the effects of this programme change. In addition, it includes the EU-wide discussion on the (limited) effectiveness of the current implementation of Leader and the search for a reorientation towards local development activities in the EU’s reform proposals. The paper frames the analysis around the notion of social innovation, a concept of central importance to the aims of Leader. It is argued that the implementation of Leader in this period falls far behind its potential to beneficially impact rural regions; hence it should be an object of critical debate in the reform of the Common Agricultural Policy and rural development measures, as well as coherence analyses with other policies, beyond 2013

Protocol for the "Michigan Awareness Control Study": A prospective, randomized, controlled trial comparing electronic alerts based on bispectral index monitoring or minimum alveolar concentration for the prevention of intraoperative awareness

<p>Abstract</p> <p>Background</p> <p>The incidence of intraoperative awareness with explicit recall is 1-2/1000 cases in the United States. The Bispectral Index monitor is an electroencephalographic method of assessing anesthetic depth that has been shown in one prospective study to reduce the incidence of awareness in the high-risk population. In the B-Aware trial, the number needed to treat in order to prevent one case of awareness in the high-risk population was 138. Since the number needed to treat and the associated cost of treatment would be much higher in the general population, the efficacy of the Bispectral Index monitor in preventing awareness in all anesthetized patients needs to be clearly established. This is especially true given the findings of the B-Unaware trial, which demonstrated no significant difference between protocols based on the Bispectral Index monitor or minimum alveolar concentration for the reduction of awareness in high risk patients.</p> <p>Methods/Design</p> <p>To evaluate efficacy in the general population, we are conducting a prospective, randomized, controlled trial comparing the Bispectral Index monitor to a non-electroencephalographic gauge of anesthetic depth. The total recruitment for the study is targeted for 30,000 patients at both low and high risk for awareness. We have developed a novel algorithm that is capable of real-time analysis of our electronic perioperative information system. In one arm of the study, anesthesia providers will receive an electronic page if the Bispectral Index value is >60. In the other arm of the study, anesthesia providers will receive a page if the age-adjusted minimum alveolar concentration is <0.5. Our minimum alveolar concentration algorithm is sensitive to both inhalational anesthetics and intravenous sedative-hypnotic agents.</p> <p>Discussion</p> <p>Awareness during general anesthesia is a persistent problem and the role of the Bispectral Index monitor in its prevention is still unclear. The Michigan Awareness Control Study is the largest prospective trial of awareness prevention ever conducted.</p> <p>Trial Registration</p> <p>Clinical Trial NCT00689091</p

Muscle weakness and lack of reflex gain adaptation predominate during post-stroke posture control of the wrist

Instead of hyper-reflexia as sole paradigm, post-stroke movement disorders are currently considered the result of a complex interplay between neuronal and muscular properties, modified by level of activity. We used a closed loop system identification technique to quantify individual contributors to wrist joint stiffness during an active posture task. Continuous random torque perturbations applied to the wrist joint by a haptic manipulator had to be resisted maximally. Reflex provoking conditions were applied i.e. additional viscous loads and reduced perturbation signal bandwidth. Linear system identification and neuromuscular modeling were used to separate joint stiffness into the intrinsic resistance of the muscles including co-contraction and the reflex mediated contribution. Compared to an age and sex matched control group, patients showed an overall 50% drop in intrinsic elasticity while their reflexive contribution did not respond to provoking conditions. Patients showed an increased mechanical stability compared to control subjects. Post stroke, we found active posture tasking to be dominated by: 1) muscle weakness and 2) lack of reflex adaptation. This adds to existing doubts on reflex blocking therapy as the sole paradigm to improve active task performance and draws attention to muscle strength and power recovery and the role of the inability to modulate reflexes in post stroke movement disorders.Mechanical, Maritime and Materials Engineerin

Hacking into bacterial biofilms: a new therapeutic challenge

Microbiologists have extensively worked during the past decade on a particular phase of the bacterial cell cycle known as biofilm, in which single-celled individuals gather together to form a sedentary but dynamic community within a complex structure, displaying spatial and functional heterogeneity. In response to the perception of environmental signals by sensing systems, appropriate responses are triggered, leading to biofilm formation. This process involves various molecular systems that enable bacteria to identify appropriate surfaces on which to anchor themselves, to stick to those surfaces and to each other, to construct multicellular communities several hundreds of micrometers thick, and to detach from the community. The biofilm microbial community is a unique, highly competitive, and crowded environment facilitating microevolutionary processes and horizontal gene transfer between distantly related microorganisms. It is governed by social rules, based on the production and use of "public" goods, with actors and recipients. Biofilms constitute a unique shield against external aggressions, including drug treatment and immune reactions. Biofilm-associated infections in humans have therefore generated major problems for the diagnosis and treatment of diseases. Improvements in our understanding of biofilms have led to innovative research designed to interfere with this process

A new approach to assessing the health benefit from obesity interventions in children and adolescents: the assessing cost-effectiveness in obesity project

OBJECTIVE: To report on a new modelling approach developed for the assessing cost-effectiveness in obesity (ACE-Obesity) project and the likely population health benefit and strength of evidence for 13 potential obesity prevention interventions in children and adolescents in Australia. METHODS: We used the best available evidence, including evidence from non-traditional epidemiological study designs, to determine the health benefits as body mass index (BMI) units saved and disability-adjusted life years (DALYs) saved. We developed new methods to model the impact of behaviours on BMI post-intervention where this was not measured and the impacts on DALYs over the child\u27s lifetime (on the assumption that changes in BMI were maintained into adulthood). A working group of stakeholders provided input into decisions on the selection of interventions, the assumptions for modelling and the strength of the evidence. RESULTS: The likely health benefit varied considerably, as did the strength of the evidence from which that health benefit was calculated. The greatest health benefit is likely to be achieved by the \u27Reduction of TV advertising of high fat and/or high sugar foods and drinks to children\u27, \u27Laparoscopic adjustable gastric banding\u27 and the \u27multi-faceted school-based programme with an active physical education component\u27 interventions. CONCLUSIONS: The use of consistent methods and common health outcome measures enables valid comparison of the potential impact of interventions, but comparisons must take into account the strength of the evidence used. Other considerations, including cost-effectiveness and acceptability to stakeholders, will be presented in future ACE-Obesity papers. Information gaps identified include the need for new and more effective initiatives for the prevention of overweight and obesity and for better evaluations of public health interventions

On the Evolutionary Modification of Self-Incompatibility: Implications of Partial Clonality for Allelic Diversity and Genealogical Structure

Experimental investigations of homomorphic self-incompatibility (SI) have revealed an unanticipated level of complexity in its expression, permitting fine regulation over the course of a lifetime or a range of environmental conditions. Many flowering plants express some level of clonal reproduction, and phylogenetic analyses suggest that clonality evolves in a correlated fashion with SI in Solanum (Solanaceae). Here, we use a diffusion approximation to explore the effects on the evolutionary dynamics of SI of vegetative propagation with SI restricted to reproduction through seed. While clonality reduces the strength of frequency-dependent selection maintaining S-allele diversity, much of the great depth typical of S-allele genealogies is preserved. Our results suggest that clonality can play an important role in the evolution of SI systems, and may afford insight into unexplained features of allele genealogies in the Solanaceae

Prevalence and progression of visual impairment in patients newly diagnosed with clinical type 2 diabetes: a 6-year follow up study

<p>Abstract</p> <p>Background</p> <p>Many diabetic patients fear visual loss as the worst consequence of diabetes. In most studies the main eye pathology is assigned as the cause of visual impairment. This study analysed a broad range of possible ocular and non-ocular predictors of visual impairment prospectively in patients newly diagnosed with clinical type 2 diabetes.</p> <p>Methods</p> <p>Data were from a population-based cohort of 1,241 persons newly diagnosed with clinical, often symptomatic type 2 diabetes aged ≥ 40 years. After 6 years, 807 patients were followed up. Standard eye examinations were done by practising ophthalmologists.</p> <p>Results</p> <p>At diabetes diagnosis median age was 65.5 years. Over 6 years, the prevalence of blindness (visual acuity of best seeing eye ≤ 0.1) rose from 0.9% (11/1,241) to 2.4% (19/807) and the prevalence of moderate visual impairment (> 0.1; < 0.5) rose from 5.4% (67/1,241) to 6.7% (54/807). The incidence (95% confidence interval) of blindness was 40.2 (25.3-63.8) per 10,000 patient-years. Baseline predictors of level of visual acuity (age, age-related macular degeneration (AMD), cataract, living alone, low self-rated health, and sedentary life-style) and speed of continued visual loss (age, AMD, diabetic retinopathy (DR), cataract, living alone, and high fasting triglycerides) were identified.</p> <p>Conclusions</p> <p>In a comprehensive assessment of predictors of visual impairment, even in a health care system allowing self-referral to free eye examinations, treatable eye pathologies such as DR and cataract emerge together with age as the most notable predictors of continued visual loss after diabetes diagnosis. Our results underline the importance of eliminating barriers to efficient eye care by increasing patients' and primary care practitioners' awareness of the necessity of regular eye examinations and timely surgical treatment.</p

An epigenetic mechanism mediates developmental nicotine effects on neuronal structure and behavior

Developmental nicotine exposure causes persistent changes in cortical neuron morphology and in behavior. We used microarray screening to identify master transcriptional or epigenetic regulators mediating these effects of nicotine and discovered increases in Ash2lmRNA, encoding a component of a histone methyltransferase complex. We therefore examined genome-wide changes in trimethylation of histone H3 on Lys4 (H3K4me3), a mark induced by the Ash2l complex associated with increased gene transcription. A large proportion of regulated promoter sites were involved in synapse maintenance. We found that Mef2c interacts with Ash2l and mediates changes in H3K4me3. Knockdown of Ash2l or Mef2c abolished nicotine-mediated alterations of dendritic complexity in vitro and in vivo, and attenuated nicotine-dependent changes in passive avoidance behavior. In contrast, overexpression mimicked nicotine-mediated alterations of neuronal structure and passive avoidance behavior. These studies identify Ash2l as a target induced by nicotinic stimulation that couples developmental nicotine exposure to changes in brain epigenetic marks, neuronal structure and behavior