Cannabis use as a means of socialization?: new consumption patterns among heavy users

Purpose: After tobacco and alcohol, cannabis is the most used substance among adolescents in Switzerland. Our aim is to assess whether cannabis use has become an ordinary means of socialization. We hypothesize that cannabis consumption has become a normative, although still illegal, behavior. Methods: As part of a larger qualitative study aimed at assessing new ways [patterns] of cannabis consumption, 16 daily cannabis consumers (11 males) and 2 former heavy consumers (both females), aged 15 to 20 years, participated in interviews and focus groups. Data were transcribed verbatim and analyzed using Atlas.ti qualitative analysis software. Results: Most consumers define the beginning of their consumption as a moment when they made new friends. They commonly use cannabis in group settings, which encourages the belief that all adolescents use cannabis. Thus, cannabis is mainly identified as an everyday social act. Joints are smoked like cigarettes: at all times of the day, during or after school or work with peers, often starting at lunch break, and mostly in public places. Friends offer a joint in a group setting, much like beer in a bar, as a means of making contact. Consumption invariably increases while socializing on vacation: "During vacation, we smoke up to 10-15 joints a day; at the end we're just dead." Additionally, in order to obtain cannabis, consumers have to be part of the right networks; they generally have several dealers to assure their supply, buy and sell themselves, or practice group-buying. As a result, all friends or acquaintances of consumers are themselves cannabis users. For instance, 4 boys, who say they are best friends, always smoke together and that, in order to quit, "All four of us should say to ourselves, 'Okay, now, let's all stop smoking'. That would be the only solution. . .but it would be impossible!" The 2 former consumers state that when they started using cannabis, "I found myself little by little in a vicious circle where I saw only people who also smoked". When they quit, they separated from their group of friends: "Either you make new friends who don't smoke or you smoke." Conclusions: Discussions with consumers demonstrate a normative facet of cannabis consumption as part of teenage socialization. Consequently, cannabis consumers develop a significant dependency since a majority of their friends use cannabis and their consumption involves most of their daily social life. Our study highlights the need for clear messages about the harmful aspects of using this substance while also suggesting that cessation efforts should include helping users separate from their consumption milieu. Sources of Support: Dept. of Public Health of the canton of Vaud.

Measuring subcompositional incoherence

Subcompositional coherence is a fundamental property of Aitchison s approach to compositional data analysis, and is the principal justification for using ratios of components. We maintain, however, that lack of subcompositional coherence, that is incoherence, can be measured in an attempt to evaluate whether any given technique is close enough, for all practical purposes, to being subcompositionally coherent. This opens up the field to alternative methods, which might be better suited to cope with problems such as data zeros and outliers, while being only slightly incoherent. The measure that we propose is based on the distance measure between components. We show that the two-part subcompositions, which appear to be the most sensitive to subcompositional incoherence, can be used to establish a distance matrix which can be directly compared with the pairwise distances in the full composition. The closeness of these two matrices can be quantified using a stress measure that is common in multidimensional scaling, providing a measure of subcompositional incoherence. The approach is illustrated using power-transformed correspondence analysis, which has already been shown to converge to log-ratio analysis as the power transform tends to zero.

Impact of a board-game approach on current smokers: a randomized controlled trial.

ABSTRACT: BACKGROUND: The main objective of our study was to assess the impact of a board game on smoking status and smoking-related variables in current smokers. To accomplish this objective, we conducted a randomized controlled trial comparing the game group with a psychoeducation group and a waiting-list control group. METHODS: The following measures were performed at participant inclusion, as well as after a 2-week and a 3-month follow-up period: "Attitudes Towards Smoking Scale" (ATS-18), "Smoking Self-Efficacy Questionnaire" (SEQ-12), "Attitudes Towards Nicotine Replacement Therapy" scale (ANRT-12), number of cigarettes smoked per day, stages of change, quit attempts, and smoking status. Furthermore, participants were assessed for concurrent psychiatric disorders and for the severity of nicotine dependence with the Fagerström Test for Nicotine Dependence (FTND). RESULTS: A time × group effect was observed for subscales of the ANRT-12, ATS-18 and SEQ-12, as well as for the number of cigarettes smoked per day. At three months follow-up, compared to the participants allocated to the waiting list group, those on Pick-Klop group were less likely to remain smoker.Outcomes at 3 months were not predicted by gender, age, FTND, stage of change, or psychiatric disorders at inclusion. CONCLUSIONS: The board game seems to be a good option for smokers. The game led to improvements in variables known to predict quitting in smokers. Furthermore, it increased smoking-cessation rates at 3-months follow-up. The game is also an interesting alternative for smokers in the precontemplation stage.

Genome-Wide Prediction Methods in Highly Diverse and Heterozygous Species: Proof-of-Concept through Simulation in Grapevine.

Nowadays, genome-wide association studies (GWAS) and genomic selection (GS) methods which use genome-wide marker data for phenotype prediction are of much potential interest in plant breeding. However, to our knowledge, no studies have been performed yet on the predictive ability of these methods for structured traits when using training populations with high levels of genetic diversity. Such an example of a highly heterozygous, perennial species is grapevine. The present study compares the accuracy of models based on GWAS or GS alone, or in combination, for predicting simple or complex traits, linked or not with population structure. In order to explore the relevance of these methods in this context, we performed simulations using approx 90,000 SNPs on a population of 3,000 individuals structured into three groups and corresponding to published diversity grapevine data. To estimate the parameters of the prediction models, we defined four training populations of 1,000 individuals, corresponding to these three groups and a core collection. Finally, to estimate the accuracy of the models, we also simulated four breeding populations of 200 individuals. Although prediction accuracy was low when breeding populations were too distant from the training populations, high accuracy levels were obtained using the sole core-collection as training population. The highest prediction accuracy was obtained (up to 0.9) using the combined GWAS-GS model. We thus recommend using the combined prediction model and a core-collection as training population for grapevine breeding or for other important economic crops with the same characteristics.

The application of NMR and MS methods for detection of adulteration of wine, fruit juices, and olive oil. A review

This review covers two important techniques, high resolution nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), used to characterize food products and detect possible adulteration of wine, fruit juices, and olive oil, all important products of the Mediterranean Basin. Emphasis is placed on the complementary use of SNIF-NMR (site-specific natural isotopic fractionation nuclear magnetic resonance) and IRMS (isotope-ratio mass spectrometry) in association with chemometric methods for detecting the adulteration.

Variance reduction methods for simulation of densities on Wiener space

We develop a general error analysis framework for the Monte Carlo simulationof densities for functionals in Wiener space. We also study variancereduction methods with the help of Malliavin derivatives. For this, wegive some general heuristic principles which are applied to diffusionprocesses. A comparison with kernel density estimates is made.

How important are tobacco prices in the propensity to start and quit smoking? An analysis of smoking histories from the Spanish National Health Survey

This paper analyses the effect of tobacco prices on the propensity tostart and quit smoking using a pool of the 1993, 1995 and 1997 editionsof the Spanish National Health Surveys. The estimates for severalparametric models of the hazard rate for starting and quitting suggestthat i) The public health measures applied as of 1992 have had asignificative effect on both reducing the hazard of starting andincreasing the hazard of quitting, ii) Prices have a very weak effect onthe hazard of starting in the male population and no significant effectin the female population, iii) The price floor of cigarrettes, proxiedby the average price of a pack of black cigarrettes, has a significanteffect on the quitting hazard which is robust across specifications andapplies to both men and women. The implied price elasticity of the timeup to quitting is situated around -1.4.

Translation to success of surgical innovation.

Contemporary thoracic and cardiovascular surgery uses extensive equipment and devices to enable its performance. As the specialties develop and new frontiers are crossed, the technology needs to advance in a parallel fashion. Strokes of genius or problem-solving brain-storming may generate great ideas, but the metamorphosis of an idea into a physical functioning tool requires a lot more than just a thinking process. A modern surgical device is the end-point of a sophisticated, complicated and potentially treacherous route, which incorporates new skills and knowledge acquisition. Processes including technology transfer, commercialisation, corporate and product development, intellectual property and regulatory routes all play pivotal roles in this voyage. Many good ideas may fall by the wayside for a multitude of reasons as they may not be marketable or may be badly marketed. In this article, we attempt to illuminate the components required in the process of surgical innovation, which we believe must remain in the remit of the modern-day thoracic and cardiovascular surgeon.

When rare is just a matter of sampling: unexpected dominance of clubtail dragonflies (Odonata, Gomphidae) through different collecting methods at Parque Nacional da Serra do Cipó, Minas Gerais State, Brazil

When rare is just a matter of sampling: Unexpected dominance of clubtail dragonflies (Odonata, Gomphidae) through different collecting methods at Parque Nacional da Serra do Cipó, Minas Gerais State, Brazil. Capture of dragonfly adults during two short expeditions to Parque Nacional da Serra do Cipó, Minas Gerais State, using three distinct collecting methodsaerial nets, Malaise and light sheet trapsis reported. The results are outstanding due the high number of species of Gomphidae (7 out of 26 Odonata species), including a new species of Cyanogomphus Selys, 1873, obtained by two non-traditional collecting methods. Because active collecting with aerial nets is the standard approach for dragonfly inventories, we discuss some aspects of the use of traps, comparing our results with those in the literature, suggesting they should be used as complementary methods in faunistic studies. Furthermore, Zonophora campanulata annulata Belle, 1983 is recorded for the first time from Minas Gerais State and taxonomic notes about Phyllogomphoides regularis (Selys, 1873) and Progomphus complicatus Selys, 1854 are also given.

Comparative abundance and diversity of Dryininae (Hymenoptera, Dryinidae) in three savannah phytophysiognomies in southeastern Brazil, under three sampling methods

Comparative abundance and diversity of Dryininae (Hymenoptera, Dryinidae) in three savannah phytophysiognomies in southeastern Brazil, under three sampling methods. This study aimed to assess the abundance and diversity of Dryininae in riparian vegetation, Brazilian savannah, and savannah woodland vegetation at the Estação Ecológica de Jataí, in Luiz Antônio, State of São Paulo, Brazil, by using Moericke, Malaise, and light traps. The sampling was carried out from December 2006 to November 2009, and 371 specimens of Dryininae were caught, with the highest frequencies in spring and summer. Fourteen species of Dryinus Latreille, 1804 and one of Thaumatodryinus Perkins, 1905 were identified. The highest frequencies of Dryinus in the riparian vegetation differed significantly from those obtained in the Brazilian savannah and savannah woodland vegetation. In the riparian vegetation, the highest number of Dryinus was collected using light traps and the interactions between abundance and the collection method used were significant. The number of specimens of Dryinus collected in the Brazilian savannah and savannah woodland vegetation using Malaise traps did not differ significantly from those obtained using Moericke traps. Males significantly outnumbered females in the sex ratio of Dryinus. The species diversity of Dryinus based on females collected using Malaise traps was high in the Brazilian savannah. Furthermore, high species richness of female Dryinus was observed in riparian vegetation (six species) and Brazilian savannah (five). The light trap was the most successful method for sampling diversity of Dryininae.

Conceptos generales y métodos de estudio en farmacogenética [General concepts and study methods in pharmacogenetics.]

Pharmacogenetics, the study of how individual genetic profiles influence the response to drugs, is an important topic. Results from pharmacogenetics studies in various clinical settings may lead to personalized medicine. Herein, we present the most important concepts of this discipline, as well as currently-used study methods.

Minimum requirements for application of ink dating methods based on solvent analysis in casework

Several ink dating methods based on solvents analysis using gas chromatography/mass spectrometry (GC/MS) were proposed in the last decades. These methods follow the drying of solvents from ballpoint pen inks on paper and seem very promising. However, several questions arose over the last few years among questioned documents examiners regarding the transparency and reproducibility of the proposed techniques. These questions should be carefully studied for accurate and ethical application of this methodology in casework. Inspired by a real investigation involving ink dating, the present paper discusses this particular issue throughout four main topics: aging processes, dating methods, validation procedures and data interpretation. This work presents a wide picture of the ink dating field, warns about potential shortcomings and also proposes some solutions to avoid reporting errors in court.

Simple and fast methods based on solid-phase extraction coupled to liquid chromatography with UV detection for the monitoring of caffeine in natural and waste waters as marker of anthropogenic impact

Two concentration methods for fast and routine determination of caffeine (using HPLC-UV detection) in surface, and wastewater are evaluated. Both methods are based on solid-phase extraction (SPE) concentration with octadecyl silica sorbents. A common “offline” SPE procedure shows that quantitative recovery of caffeine is obtained with 2 mL of an elution mixture solvent methanol-water containing at least 60% methanol. The method detection limit is 0.1 μg L−1 when percolating 1 L samples through the cartridge. The development of an “online” SPE method based on a mini-SPE column, containing 100 mg of the same sorbent, directly connected to the HPLC system allows the method detection limit to be decreased to 10 ng L−1 with a sample volume of 100 mL. The “offline” SPE method is applied to the analysis of caffeine in wastewater samples, whereas the “on-line” method is used for analysis in natural waters from streams receiving significant water intakes from local wastewater treatment plants