843 research outputs found
Revue systĂ©matique dâessais comparatifs randomisĂ©s dâinterventions dâabandon du tabac chez les jeunes
Contexte : Bien que lâusage de la cigarette demeure courant parmi les jeunes, on en sait encore bien peu sur la façon de les aider Ă cesser de fumer. Seulement quelques revues systĂ©matiques dâessais comparatifs randomisĂ©s (ECR) ont Ă©valuĂ© lâefficacitĂ© des interventions dâabandon du tabac chez les jeunes.Objectif : RĂ©sumer les connaissances sur lâefficacitĂ© des interventions visant Ă aider les jeunes Ă cesser de fumer en se basant sur des donnĂ©es probantes provenant dâECR.SĂ©lection des Ă©tudes et extraction des donnĂ©es : Nous avons retenu tous les ECR publiĂ©s qui Ă©valuaient les interventions dâabandon du tabac ciblant les jeunes ĂągĂ©s de 20 ans et moins et qui rapportaient lâabstinence au tabac selon une analyse en intention de traiter. Nous avons relevĂ© les Ă©tudes pertinentes provenant de huit revues de synthĂšse dĂ©crivant des Ă©tudes portant sur des interventions dâabandon du tabac publiĂ©es entre 2002 et 2006, ainsi quâune recherche menĂ©e dans les bases de donnĂ©es PubMed et PsycINFO entre 2001 et novembre  2006. Nous rapportons lâabstinence au tabagisme au moment du suivi le plus prolongĂ©. Les auteurs ont sĂ©lectionnĂ© dâun commun accord les donnĂ©es retenues pour cette revue.RĂ©sultats : Nous avons identifiĂ© 16 ECR auxquels ont participĂ© 6 623 jeunes ; 11 Ă©tudes Ă©valuant des interventions comportementales qui comprenaient 5 764 participants; quatre examinant des interventions pharmacologiques qui comptaient 529 participants ; et une se penchant sur lâacupuncture au laser qui comportait 330 participants. Trois interventions comportementales menĂ©es en milieu scolaire sur quatre et une intervention rĂ©alisĂ©e en milieu de soins de santĂ© sur quatre ont fait augmenter de façon significative lâabstinence au tabac, quatre semaines Ă 24 mois suivant les interventions. Parmi les quatre ERC qui Ă©valuaient les interventions pharmacologiques rĂ©alisĂ©es Ă lâaide soit de bupropion, de timbres ou de gommes Ă la nicotine, une Ă©tude, oĂč le timbre Ă la nicotine a Ă©tĂ© utilisĂ© en combinaison avec un counseling cognitivo-comportemental, a montrĂ© une hausse marquĂ©e, quoique non significative, de lâabstinence six mois aprĂšs la date dâabandon.Conclusion : Il existe encore peu de preuves dĂ©montrant lâefficacitĂ© des interventions dâabandon du tabac chez les jeunes. Quatre programmes en milieu scolaire et une intervention dans un Ă©tablissement de santĂ© ont mis en Ă©vidence une certaine efficacitĂ©, tandis que pour la thĂ©rapie pharmacologique, les rĂ©sultats 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 jĂłvenes, todavĂa no se sabe mucho sobre cĂłmo ayudarlos a dejar de fumar. Solamente algunas revisiones sistemĂĄticas de ensayos comparativos aleatorizados han evaluado la eficacia de las intervenciones dirigidas a lograr el abandono del tabaco entre los jĂłvenes.Objetivo: resumir los conocimientos sobre la eficacia de las intervenciones destinadas a ayudar a jĂłvenes a dejar de fumar sobre la base de los datos probados de los ensayos comparativos aleatorizados.SelecciĂłn de estudios y extracciĂłn de datos: hemos retenido todos los ensayos comparativos aleatorizados publicados, que evalĂșan las intervenciones de abandono del tabaco en los jĂłvenes de 20 años y menos, y que informan sobre la abstinencia de tabaco, segĂșn un anĂĄlisis que tiene la intenciĂłn de tratar. Hemos seleccionado los trabajos pertinentes provenientes de ocho revistas de sĂntesis, que describen estudios referidos a intervenciones de abandono del tabaco publicados entre 2002 y 2006, asĂ como una investigaciĂłn 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 mĂĄs prolongado. Los autores han seleccionado de comĂșn acuerdo los datos retenidos por esta revista.Resultados: hemos identificado diecisĂ©is estudios comparativos aleatorizados en los que participaron 6.623 jĂłvenes; once estudios que evalĂșan las intervenciones comportamentales, con 5.764 participantes; cuatro que examinan las intervenciones farmacolĂłgicas en las que intervienen 529 participantes y uno que se centra en la acupuntura al lĂĄser, con 330 participantes. Tres intervenciones comportamentales realizadas en medio escolar de cada cuatro y una intervenciĂłn realizada en el medio de la atenciĂłn sanitaria de cada cuatro, aumentaron de manera significativa la abstinencia al tabaco, cuatro semanas a 24 meses despuĂ©s de las intervenciones. Entre los cuatro estudios comparativos aleatorizados que evaluaban las intervenciones farmacolĂłgicas, realizadas ya sea con ayuda de bupropion, de parches o de gomas de mascar a la nicotina, uno de ellos, en el que se utilizĂł un parche de nicotina en combinaciĂłn con orientaciĂłn psicolĂłgica cognitivo-comportamental, indicĂł un aumento marcado, aunque no significativo, de la abstinencia, seis meses despuĂ©s de la fecha de abandono.ConclusiĂłn: existen todavĂa pocas pruebas que demuestren la eficacia de las intervenciones de abandono del tabaco entre los jĂłvenes. Cuatro programas en medio escolar y una intervenciĂłn en un establecimiento de salud evidenciaron una cierta eficacia, mientras que los resultados no son todavĂa concluyentes en lo que se refiere a la terapia farmacolĂłgica
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 0â25 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 ”M Hg(II) to reduced clay suspensions (4 g clay Lâ»Âč) 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 (0â10 mM) and at pH 5â9 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 (2.8â24.8% 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 0â25 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 ”M Hg(II) to reduced clay suspensions (4 g clay Lâ»Âč) 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 (0â10 mM) and at pH 5â9 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 (2.8â24.8% 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 depressionâbody 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.âŻData 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 individualâs 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
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