Revue systématique d’essais comparatifs randomisés d’interventions d’abandon du tabac chez les jeunes

Contexte : Bien que l’usage de la cigarette demeure courant parmi les jeunes, on en sait encore bien peu sur la façon de les aider à cesser de fumer. Seulement quelques revues systématiques d’essais comparatifs randomisés (ECR) ont évalué l’efficacité des interventions d’abandon du tabac chez les jeunes.Objectif : Résumer les connaissances sur l’efficacité des interventions visant à aider les jeunes à cesser de fumer en se basant sur des données probantes provenant d’ECR.Sélection des études et extraction des données : Nous avons retenu tous les ECR publiés qui évaluaient les interventions d’abandon du tabac ciblant les jeunes âgés de 20 ans et moins et qui rapportaient l’abstinence au tabac selon une analyse en intention de traiter. Nous avons relevé les études pertinentes provenant de huit revues de synthèse décrivant des études portant sur des interventions d’abandon du tabac publiées entre 2002 et 2006, ainsi qu’une recherche menée dans les bases de données PubMed et PsycINFO entre 2001 et novembre  2006. Nous rapportons l’abstinence au tabagisme au moment du suivi le plus prolongé. Les auteurs ont sélectionné d’un commun accord les données retenues pour cette revue.Résultats : Nous avons identifié 16 ECR auxquels ont participé 6 623 jeunes ; 11 études évaluant des interventions comportementales qui comprenaient 5 764 participants; quatre examinant des interventions pharmacologiques qui comptaient 529 participants ; et une se penchant sur l’acupuncture au laser qui comportait 330 participants. Trois interventions comportementales menées en milieu scolaire sur quatre et une intervention réalisée en milieu de soins de santé sur quatre ont fait augmenter de façon significative l’abstinence au tabac, quatre semaines à 24 mois suivant les interventions. Parmi les quatre ERC qui évaluaient les interventions pharmacologiques réalisées à l’aide soit de bupropion, de timbres ou de gommes à la nicotine, une étude, où le timbre à la nicotine a été utilisé en combinaison avec un counseling cognitivo-comportemental, a montré une hausse marquée, quoique non significative, de l’abstinence six mois après la date d’abandon.Conclusion : Il existe encore peu de preuves démontrant l’efficacité des interventions d’abandon du tabac chez les jeunes. Quatre programmes en milieu scolaire et une intervention dans un établissement de santé ont mis en évidence une certaine efficacité, tandis que pour la thérapie pharmacologique, les résultats ne sont pas encore concluants.Background: Cigarette use remains common among young people but little is known about how to help adolescent smokers quit. There are few systematic reviews of randomized controlled trials (RCTs) that evaluate the effectiveness of cessation interventions for youth.Objective: To synthesize knowledge on the effectiveness of cessation interventions targeted to youth based on evidence from RCTs.Selection of studies and data extraction: We retained all published RCTs with intention to treat analyses that evaluated cessation interventions targeted to youth aged ≤ 20 years. Relevant studies were identified from eight review articles of smoking cessation intervention studies published between 2002 and 2006, and from a search conducted in PubMed and PsycINFO databases from 2001 to November 2006. The outcome of primary interest was abstinence at the longest reported follow-up. Extraction of data was by consensus of the authors. Results: We identified 16 RCTs with a total of 6623 participants; 11 studies that included 5764 participants evaluated behavioural interventions, four with 529 participants evaluated pharmacological interventions, and one with 330 participants evaluated a laser acupuncture intervention. Three of four behavioural interventions conducted in school settings, and one of four conducted in a health care setting significantly increased abstinence four weeks to 24 months after the interventions. Of four RCTs that evaluated pharmacological interventions using either bupropion or nicotine patch or gum, one study using the nicotine patch coupled with cognitive-behavioural counselling showed a marked albeit non-significant increase in abstinence six months after quit date.Conclusion: There is still limited evidence demonstrating the efficacy of smoking cessation interventions in youth. Four school-based programs and one intervention in a health care setting have shown efficacy, while results for pharmacological therapy are inconsistent across studies.Contexto: si bien el tabaco sigue siendo de uso corriente entre los jóvenes, todavía no se sabe mucho sobre cómo ayudarlos a dejar de fumar. Solamente algunas revisiones sistemáticas de ensayos comparativos aleatorizados han evaluado la eficacia de las intervenciones dirigidas a lograr el abandono del tabaco entre los jóvenes.Objetivo: resumir los conocimientos sobre la eficacia de las intervenciones destinadas a ayudar a jóvenes a dejar de fumar sobre la base de los datos probados de los ensayos comparativos aleatorizados.Selección de estudios y extracción de datos: hemos retenido todos los ensayos comparativos aleatorizados publicados, que evalúan las intervenciones de abandono del tabaco en los jóvenes de 20 años y menos, y que informan sobre la abstinencia de tabaco, según un análisis que tiene la intención de tratar. Hemos seleccionado los trabajos pertinentes provenientes de ocho revistas de síntesis, que describen estudios referidos a intervenciones de abandono del tabaco publicados entre 2002 y 2006, así como una investigación llevada a cabo en las bases de datos PubMed et PsycINFO, realizada entre 2001 y noviembre de 2006. Informamos sobre la abstinencia del tabaquismo en el momento de seguimiento más prolongado. Los autores han seleccionado de común acuerdo los datos retenidos por esta revista.Resultados: hemos identificado dieciséis estudios comparativos aleatorizados en los que participaron 6.623 jóvenes; once estudios que evalúan las intervenciones comportamentales, con 5.764 participantes; cuatro que examinan las intervenciones farmacológicas en las que intervienen 529 participantes y uno que se centra en la acupuntura al láser, con 330 participantes. Tres intervenciones comportamentales realizadas en medio escolar de cada cuatro y una intervención realizada en el medio de la atención sanitaria de cada cuatro, aumentaron de manera significativa la abstinencia al tabaco, cuatro semanas a 24 meses después de las intervenciones. Entre los cuatro estudios comparativos aleatorizados que evaluaban las intervenciones farmacológicas, realizadas ya sea con ayuda de bupropion, de parches o de gomas de mascar a la nicotina, uno de ellos, en el que se utilizó un parche de nicotina en combinación con orientación psicológica cognitivo-comportamental, indicó un aumento marcado, aunque no significativo, de la abstinencia, seis meses después de la fecha de abandono.Conclusión: existen todavía pocas pruebas que demuestren la eficacia de las intervenciones de abandono del tabaco entre los jóvenes. Cuatro programas en medio escolar y una intervención en un establecimiento de salud evidenciaron una cierta eficacia, mientras que los resultados no son todavía concluyentes en lo que se refiere a la terapia farmacológica

Reduction of Hg(II) by Fe(II)-Bearing Smectite Clay Minerals

Aluminosilicate clay minerals are often a major component of soils and sediments and many of these clays contain structural Fe (e.g., smectites and illites). Structural Fe(III) in smectite clays is redox active and can be reduced to Fe(II) by biotic and abiotic processes. Fe(II)-bearing minerals such as magnetite and green rust can reduce Hg(II) to Hg(0); however, the ability of other environmentally relevant Fe(II) phases, such as structural Fe(II) in smectite clays, to reduce Hg(II) is largely undetermined. We conducted experiments examining the potential for reduction of Hg(II) by smectite clay minerals containing 0–25 wt% Fe. Fe(III) in the clays (SYn-1 synthetic mica-montmorillonite, SWy-2 montmorillonite, NAu-1 and NAu-2 nontronite, and a nontronite from Cheney, Washington (CWN)) was reduced to Fe(II) using the citrate-bicarbonate-dithionite method. Experiments were initiated by adding 500 µM Hg(II) to reduced clay suspensions (4 g clay L⁻¹) buffered at pH 7.2 in 20 mM 3-morpholinopropane-1-sulfonic acid (MOPS). The potential for Hg(II) reduction in the presence of chloride (0–10 mM) and at pH 5–9 was examined in the presence of reduced NAu-1. Analysis of the samples by Hg LIII-edge X-ray absorption fine structure (XAFS) spectroscopy indicated little to no reduction of Hg(II) by SYn-1 (0% Fe), while reduction of Hg(II) to Hg(0) was observed in the presence of reduced SWy-2, NAu-1, NAu-2, and CWN (2.8–24.8% Fe). Hg(II) was reduced to Hg(0) by NAu-1 at all pH and chloride concentrations examined. These results suggest that Fe(II)-bearing smectite clays may contribute to Hg(II) reduction in suboxic/anoxic soils and sediments

Reduction of Hg(II) by Fe(II)-Bearing Smectite Clay Minerals

Aluminosilicate clay minerals are often a major component of soils and sediments and many of these clays contain structural Fe (e.g., smectites and illites). Structural Fe(III) in smectite clays is redox active and can be reduced to Fe(II) by biotic and abiotic processes. Fe(II)-bearing minerals such as magnetite and green rust can reduce Hg(II) to Hg(0); however, the ability of other environmentally relevant Fe(II) phases, such as structural Fe(II) in smectite clays, to reduce Hg(II) is largely undetermined. We conducted experiments examining the potential for reduction of Hg(II) by smectite clay minerals containing 0–25 wt% Fe. Fe(III) in the clays (SYn-1 synthetic mica-montmorillonite, SWy-2 montmorillonite, NAu-1 and NAu-2 nontronite, and a nontronite from Cheney, Washington (CWN)) was reduced to Fe(II) using the citrate-bicarbonate-dithionite method. Experiments were initiated by adding 500 µM Hg(II) to reduced clay suspensions (4 g clay L⁻¹) buffered at pH 7.2 in 20 mM 3-morpholinopropane-1-sulfonic acid (MOPS). The potential for Hg(II) reduction in the presence of chloride (0–10 mM) and at pH 5–9 was examined in the presence of reduced NAu-1. Analysis of the samples by Hg LIII-edge X-ray absorption fine structure (XAFS) spectroscopy indicated little to no reduction of Hg(II) by SYn-1 (0% Fe), while reduction of Hg(II) to Hg(0) was observed in the presence of reduced SWy-2, NAu-1, NAu-2, and CWN (2.8–24.8% Fe). Hg(II) was reduced to Hg(0) by NAu-1 at all pH and chloride concentrations examined. These results suggest that Fe(II)-bearing smectite clays may contribute to Hg(II) reduction in suboxic/anoxic soils and sediments

Cost Minimization of Virtual Machine Allocation in Public Clouds Considering Multiple Applications

International Conference, GECON 2017 (14. 2017. Biarritz)This paper presents a virtual machine (VM) allocation strategy to optimize the cost of VM deployments in public clouds. It can simultaneously deal with multiple applications and it is formulated as an optimization problem that takes the level of performance to be reached by a set of applications as inputs. It considers real characteristics of infrastructure providers such as VM types, limits on the number VMs that can be deployed, and pricing schemes. As output, it generates a VM allocation to support the performance requirements of all the applications. The strategy combines short-term and long-term allocation phases in order to take advantage of VMs belonging to two different pricing categories: on-demand and reserved. A quantization technique is introduced to reduce the size of the allocation problem and, thus, significantly decrease the computational complexity. The experiments show that the strategy can optimize costs for problems that could not be solved with previous approache

Self-Duality in D <= 8-dimensional Euclidean Gravity

In the context of D-dimensional Euclidean gravity, we define the natural generalisation to D-dimensions of the self-dual Yang-Mills equations, as duality conditions on the curvature 2-form of a Riemannian manifold. Solutions to these self-duality equations are provided by manifolds of SU(2), SU(3), G_2 and Spin(7) holonomy. The equations in eight dimensions are a master set for those in lower dimensions. By considering gauge fields propagating on these self-dual manifolds and embedding the spin connection in the gauge connection, solutions to the D-dimensional equations for self-dual Yang-Mills fields are found. We show that the Yang-Mills action on such manifolds is topologically bounded from below, with the bound saturated precisely when the Yang-Mills field is self-dual. These results have a natural interpretation in supersymmetric string theory.Comment: 9 pages, Latex, factors in eqn. (6) corrected, acknowledgement and reference added, typos fixe

Simulated distributions from negative experiments highlight the importance of the body mass index distribution in explaining depression–body mass index genetic risk score interactions

This is the final version. Available on open access from Oxford University Press via the DOI in this record. Data availability: All data from UK Biobank are publicly available; the negative experiments algorithm can be found here https://github.com/drar wood/gags.Abstract. Background: Depression and obesity are complex global health problems. Recent studies suggest a genetic predisposition to obesity might be accentuated in people with depression, but these analyses are prone to bias. Here, we tested the hypothesis that depression accentuates genetic susceptibility to obesity and applied negative control experiments to test whether any observed interactions were real or driven by confounding and statistical biases. Methods: We used data from upto 378,000 Europeans in UK Biobank, a 73 variant Body Mass Index (BMI) genetic risk score, 2 depression measures (depressive symptoms (DS), major depression (MD)) and an antidepressant usage variable available. We tested whether a) depression and b) antidepressant treatment accentuated genetic susceptibility to obesity. Finally, we performed negative control experiments by sampling individuals at random so that they had BMI distributions identical to depression cases and controls. Results: Depression was associated with an accentuation of an individuals genetic risk of obesity with evidence of interactions for both DS and MD (Pinteraction=7x10-4 and 7x10-5 respectively). Antidepressant usage within DS cases accentuated genetic obesity risk (Pinteraction=9x10-4), but not for MD (Pinteraction=0.13). Negative control experiments suggested that the observed interactions for MD (empirical-P =0.067) may be driven by statistical biases or confounding factors but were not possible with the larger DS groups. Antidepressant usage interaction also appears to be driven by statistical artefacts (empirical-P=0.510 using MD and 0.162 using DS). Conclusion: We have highlighted the importance of running negative experiments to confirm putative interactions in gene-environment studies. We provide some tentative evidence that depression accentuates an individual’s genetic susceptibility to higher BMI but demonstrated that the BMI distributions within cases and controls might drive these interactions.Academy of Medical SciencesEuropean Research Council (ERC

Laminin N-terminus α31 is upregulated in invasive ductal breast cancer and changes the mode of tumour invasion

Laminin N-terminus α31 (LaNt α31) is an alternative splice isoform derived from the laminin α3 gene. The LaNt α31 protein is enriched around the terminal duct lobular units in normal breast tissue. In the skin and cornea the protein influences epithelial cell migration and tissue remodelling. However, LaNt α31 has never been investigated in a tumour environment. Here we analysed LaNt α31 in invasive ductal carcinoma and determined its contribution to breast carcinoma invasion. LaNt α31 expression and distribution were analysed by immunohistochemistry in human breast tissue biopsy sections and tissue microarrays covering 232 breast cancer samples. This analysis revealed LaNt α31 to be upregulated in 56% of invasive ductal carcinoma specimens compared with matched normal tissue, and further increased in nodal metastasis compared with the tumour mass in 45% of samples. 65.8% of triple negative cases displayed medium to high LaNt α31 expression. To study LaNt α31 function, an adenoviral system was used to induce expression in MCF-7 and MDA-MB-231 cells. 2D cell migration and invasion into collagen hydrogels were not significantly different between LaNt α31 overexpressing cells and control treated cells. However, LaNt α31 overexpression reduced the proliferation rate of MCF-7 and MDA-MB-231 cells. Moreover, LaNt α31 overexpressing MDA-MB-231 cells displayed a striking change in their mode of invasion into laminin-containing Matrigel; changing from multicellular streaming to individual cellular-invasion. In agreement with these results, 66.7% of the tumours with the highest LaNt α31 expression were non-cohesive. Together these findings indicate that breast cancer-associated changes in LaNt α31 expression could contribute to the processes involved in tumour invasion and may represent a new therapeutic target.</jats:p

Searching for a Connection Between Matroid Theory and String Theory

We make a number of observations about matter-ghost string phase, which may eventually lead to a formal connection between matroid theory and string theory. In particular, in order to take advantage of the already established connection between matroid theory and Chern-Simons theory, we propose a generalization of string theory in terms of some kind of Kahler metric. We show that this generalization is closely related to the Kahler-Chern-Simons action due to Nair and Schiff. In addition, we discuss matroid/string connection via matroid bundles and a Schild type action, and we add new information about the relationship between matroid theory, D=11 supergravity and Chern-Simons formalism.Comment: 28 pages, LaTex, section 6 and references adde

Introducing SpatialGridBuilder: A new system for creating geo-coded datasets

Researchers in the conflict research community have become increasingly aware that we can no longer depend on state-aggregated data. Numerous factors at the substate level affect the nature of human interactions, so if we really want to understand conflict, we need to find more appropriate units of analysis. However, while many conflict researchers have realized this, actually taking the next step and performing data analysis on spatial data grids has remained a rather elusive goal for many because of the difficulty of learning the new techniques to perform such analyses. This paper introduces SpatialGridBuilder, a new, freely available, open-source system with the goal of empowering conflict researchers with no background in GIS methods to start their own spatial analyses. SpatialGridBuilder allows the researcher to: (a) create entirely new spatial datasets, based on the needs of their own research; (b) import their own spatial data; (c) easily add a range of important variables to the datasets, including commonly used conflict variables, plus new variables that have not been presented before; and (d) visualize graphical renderings of this data. Having done this, SpatialGridBuilder will then export the dataset for the researcher to analyse using conventional statistical methods. This article introduces the new program, and demonstrates how it can be used to set up such a statistical analysis. It also shows how different results can be achieved by building grids of different resolutions, thereby encouraging researchers to choose grid resolutions appropriate to their research questions and data. The article also introduces a novel means of determining infrastructure complexity, using Google maps