3,154 research outputs found

    Paternal Psychosocial Characteristics and Corporal Punishment of their 3-Year Old Children

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    This study uses data from 2,309 biological fathers who participated in the Fragile Families and Child Wellbeing Study (FFCWS) to examine associations between psychosocial characteristics and levels of corporal punishment (CP) toward their 3-year old children over the past month. Results indicate that 61% of the fathers reported no CP over the past month, 23% reported using CP once or twice, and 16% reported using CP a few times in the past month or more. In multivariate models controlling for important socio-demographic factors as well as characteristics of the child, fathers’ parenting stress, major depression, alcohol use, and drug use were significantly associated with greater use of CP, whereas involvement with the child and generalized anxiety order were not. Girls were less likely to be the recipient of CP than boys, and child externalizing behavior problems but not internalizing behavior problems were associated with more CP.Fragile families, childbearing, nonmarital childbearing, fartherhood, fathers, corporal punishment, behavior problems, stress, depression

    Extending Johnson's and Morita's homomorphisms to the mapping class group

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    We extend certain homomorphisms defined on the higher Torelli subgroups of the mapping class group to crossed homomorphisms defined on the entire mapping class group. In particular, for every k2k\geq 2, we construct a crossed homomorphism ϵk\epsilon_k which extends Morita's homomorphism τ~k\tilde \tau_k to the entire mapping class group. From this crossed homomorphism we also obtain a crossed homomorphism extending the kkth Johnson homomorphism τk\tau_k to the mapping class group. D. Johnson and S. Morita obtained their respective homomorphisms by considering the action of the mapping class group on the nilpotent truncations of the surface group; our approach is to mimic Morita's construction topologically by using nilmanifolds associated to these truncations. This allows us to take the ranges of these crossed homomorphisms to be certain finite-dimensional real vector spaces associated to these nilmanifolds.Comment: 32 pages; cleaned up and minor corrections to proofs; updated to agree with version published by Alg. & Geom. Top at: http://msp.warwick.ac.uk/agt/2007/07/p050.xhtm

    The scale of predictability

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    We introduce a new stylized fact: the hump-shaped behavior of slopes and coefficients of determination as a function of the aggregation horizon when running (forward/backward) predictive regressions of future excess market returns onto past economic uncertainty (as proxied by market variance, consumption variance, or economic policy uncertainty). To justify this finding formally, we propose a novel modeling framework in which predictability is specified as a property of low-frequency components of both excess market returns and economic uncertainty. We dub this property scale-specific predictability. We show that classical predictive systems imply restricted forms of scale-specific predictability. We conclude that for certain predictors, like economic uncertainty, the restrictions imposed by classical predictive systems may be excessively strong

    Les cycles évanescents sont dénoués

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    Iron deficiency intravenous substitution in a Swiss academic primary care division: analysis of practices.

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    BACKGROUND: Iron deficiency is a common problem in primary care and is usually treated with oral iron substitution. With the recent simplification of intravenous (IV) iron administration (ferric carboxymaltose) and its approval in many countries for iron deficiency, physicians may be inclined to overutilize it as a first-line substitution. OBJECTIVE: The aim of this study was to evaluate iron deficiency management and substitution practices in an academic primary care division 5 years after ferric carboxymaltose was approved for treatment of iron deficiency in Switzerland. METHODS: All patients treated for iron deficiency during March and April 2012 at the Geneva University Division of Primary Care were identified. Their medical files were analyzed for information, including initial ferritin value, reasons for the investigation of iron levels, suspected etiology, type of treatment initiated, and clinical and biological follow-up. Findings were assessed using an algorithm for iron deficiency management based on a literature review. RESULTS: Out of 1,671 patients, 93 were treated for iron deficiency. Median patients' age was 40 years and 92.5% (n=86) were female. The average ferritin value was 17.2 μg/L (standard deviation 13.3 μg/L). The reasons for the investigation of iron levels were documented in 82% and the suspected etiology for iron deficiency was reported in 67%. Seventy percent of the patients received oral treatment, 14% IV treatment, and 16% both. The reasons for IV treatment as first- and second-line treatment were reported in 57% and 95%, respectively. Clinical and biological follow-up was planned in less than two-thirds of the cases. CONCLUSION: There was no clear overutilization of IV iron substitution. However, several steps of the iron deficiency management were not optimally documented, suggesting shortcuts in clinical reasoning

    Molecular Evolution in Time Dependent Environments

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    The quasispecies theory is studied for dynamic replication landscapes. A meaningful asymptotic quasispecies is defined for periodic time dependencies. The quasispecies' composition is constantly changing over the oscillation period. The error threshold moves towards the position of the time averaged landscape for high oscillation frequencies and follows the landscape closely for low oscillation frequencies.Comment: 5 pages, 3 figures, Latex, uses Springer documentclass llncs.cl

    Perceived risk of harm and intentions of future inhalant use among adolescent inhalant users

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    To identify predictors of perceived a) risk of harm associated with inhalant use and b) intention to use inhalants among adolescent inhalant users

    Actions of the braid group, and new algebraic proofs of results of Dehornoy and Larue

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    This article surveys many standard results about the braid group with emphasis on simplifying the usual algebraic proofs. We use van der Waerden's trick to illuminate the Artin-Magnus proof of the classic presentation of the algebraic mapping-class group of a punctured disc. We give a simple, new proof of the Dehornoy-Larue braid-group trichotomy, and, hence, recover the Dehornoy right-ordering of the braid group. We then turn to the Birman-Hilden theorem concerning braid-group actions on free products of cyclic groups, and the consequences derived by Perron-Vannier, and the connections with the Wada representations. We recall the very simple Crisp-Paris proof of the Birman-Hilden theorem that uses the Larue-Shpilrain technique. Studying ends of free groups permits a deeper understanding of the braid group; this gives us a generalization of the Birman-Hilden theorem. Studying Jordan curves in the punctured disc permits a still deeper understanding of the braid group; this gave Larue, in his PhD thesis, correspondingly deeper results, and, in an appendix, we recall the essence of Larue's thesis, giving simpler combinatorial proofs.Comment: 51`pages, 13 figure

    Kinematic Characterisation of Hexapods for Industry

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    International audiencePurpose-The aim of this paper is to propose two simple tools for the kinematic characterization of hexapods. The paper also aims to share the authors' experience with converting a popular commercial motion base (Stewart-Gough platform, hex-apod) to an industrial robot for use in heavy duty aerospace manufacturing processes. Design/methodology/approach-The complete workspace of a hexapod is a six-dimensional entity that is impossible to visualize. Thus, nearly all hexapod manufacturers simply state the extrema of each of the six dimensions, which is very misleading. As a compromise, we propose a special three-dimensional subset of the complete workspace, an approximation of which can be readily obtained using a CAD/CAM software suite, such as CATIA. While calibration techniques for serial robots are readily available, there is still no generally-agreed procedure for calibrating hexapods. We propose a simple calibration method that relies on the use of a laser tracker and requires no programming at all. Instead, the design parameters of the hexapod are directly and individually measured and the few computations involved are performed in a CAD/CAM software such as CATIA. Findings-The conventional octahedral hexapod design has a very limited workspace, though free of singularities. There are important deviations between the actual and the specified kinematic model in a commercial motion base. Practical implications-A commercial motion base can be used as a precision positioning device with its controller retrofit-ted with state-of-the-art motion control technology with accurate workspace and geometric characteristics. Originality/value-A novel geometric approach for obtaining meaningful measures of the workspace is proposed. A novel, systematic procedure for the calibration of a hexapod is outlined. Finally, experimental results are presented and discussed

    Inflammatory response of endothelial cells to a human endogenous retrovirus associated with multiple sclerosis is mediated by TLR4.

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    The MSRV (multiple sclerosis-associated retrovirus) belongs to the human endogenous retrovirus HERV-W family. The envelope protein originating from the MSRV has been found in most patients with multiple sclerosis (MS). This protein (Env-ms) has pro-inflammatory properties for several types of immune cells and could therefore play a role in MS pathogenesis by promoting the leukocyte diapedesis observed in the central nervous system of patients. Our study aims to analyze the effects of Env-ms on the blood-brain barrier (BBB) at a molecular and functional level. We demonstrate that the recombinant MSRV envelope is able to stimulate several inflammatory parameters in a human BBB in vitro model, the HCMEC/D3 brain endothelial cell line. Indeed, Env-ms induces over-expression of ICAM-1, a major mediator of leukocyte adhesion to endothelial cells, in a dose-dependent manner as well as a strong dose-dependent production of the pro-inflammatory cytokines IL-6 and IL-8. Furthermore, using a silencing approach with siRNAs, we show that Env-ms is recognized via the Toll-like receptor 4 receptor, a pattern recognition receptor of innate immunity present on endothelial cells. We also show, using functional assays, that treatment of brain endothelial cells with Env-ms significantly stimulated the adhesion and the transmigration of activated immune cells through a monolayer of endothelial cells. These findings support the hypothesis that MSRV could be involved in the pathogenesis of MS disease or at least in maintenance of inflammatory conditions, thus fueling the auto-immune disorder. MSRV could also play a role in other chronic inflammatory diseases
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