13,705 research outputs found

    On the future infimum of positive self-similar Markov processes

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    We establish integral tests and laws of the iterated logarithm for the upper envelope of the future infimum of positive self-similar Markov processes and for increasing self-similar Markov processes at 0 and infinity. Our proofs are based on the Lamperti representation and time reversal arguments due to Chaumont and Pardo [9]. These results extend laws of the iterated logarithm for the future infimum of Bessel processes due to Khoshnevisan et al. [11]

    An exploratory canonical analysis approach for multinomial populations based on the Ď•\phi-divergence measure

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    summary:In this paper we consider an exploratory canonical analysis approach for multinomial population based on the Ď•\phi -divergence measure. We define the restricted minimum Ď•\phi -divergence estimator, which is seen to be a generalization of the restricted maximum likelihood estimator. This estimator is then used in Ď•\phi -divergence goodness-of-fit statistics which is the basis of two new families of statistics for solving the problem of selecting the number of significant correlations as well as the appropriateness of the model

    Interventions for promoting reintegration and reducing harmful behaviour and lifestyles in street-connected children and young people (Review)

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    Background Millions of street-connected children and young people worldwide live or work in street environments. They are vulnerable to many risks, whether or not they remain connected to families of origin, and despite many strengths and resiliencies, they are excluded from mainstream social structures and opportunities. Objectives Primary research objectives To evaluate and summarise the effectiveness of interventions for street-connected children and young people that aim to: • promote inclusion and reintegration; • increase literacy and numeracy; • facilitate access to education and employment; • promote mental health, including self esteem; • reduce harms associated with early sexual activity and substance misuse. Secondary research objectives • To explore whether effects of interventions differ within and between populations, and whether an equity gradient influences theseeffects, by extrapolating from all findings relevance for low- and middle-income countries (LMICs) (Peters 2004). • To describe other health, educational, psychosocial and behavioural effects, when appropriate outcomes are reported. • To explore the influence of context in design, delivery and outcomes of interventions. Interventions for promoting reintegration and reducing harmful behaviour and lifestyles in street-connected children and young people 1 (Review) Copyright © 2016 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. To explore the relationship between numbers of components and duration and effects of interventions. • To highlight implications of these findings for further research and research methods to improve evidence in relation to the primary research objective. • To consider adverse or unintended outcomes. Search methods We searched the following bibliographic databases, searched for the original review, from inception to 2012, and various relevant non-governmental and organisational websites: Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE and PreMEDLINE;EMBASE and EMBASE Classic; Cumulative Index to Nursing and Allied Health Literature (CINAHL); PsycINFO; Education Resource Information Center (ERIC); Sociological Abstracts; Social Services Abstracts; Social Work Abstracts; Healthstar; Latin American Caribbean Health Sciences Literature (LILACS); System for Grey literature in Europe (OpenGrey); ProQuest Dissertations and Theses; EconLit; IDEAS Economics and Finance Research; JOLIS Library Catalog of the holdings of the World Bank Group and International Monetary Fund (IMF) Libraries; British Library for Development Studies (BLDS); Google and Google Scholar. We updated the search in April 2015 for the review update, using the same methods. Selection criteria This review includes data from harm reduction or reintegration intervention studies that used a comparison group study design; all were randomised or quasi-randomised studies. Studies were included if they evaluated interventions provided for street-connected children and young people, from birth to 24 years, in all contexts. Data collection and analysis Two review authors independently extracted data and assessed risk of bias and other factors presented in the Discussion and Summary quality assessment (Grades of Recommendation, Assessment, Development and Evaluation (GRADE)). We extracted data on intervention delivery, context, process factors, equity and outcomes, and grouped outcomes into psychosocial outcomes, risky sexual behaviours or substance use. We conducted meta-analyses for outcomes where the outcome measures were sufficiently similar. We evaluated other outcomes narratively. Main results We included 13 studies evaluating 19 interventions from high-income countries (HICs). We found no sufficiently robust evaluations conducted in low- and middle-income countries (LMICs). Study quality overall was low and measurements used by studies variable. Participants were classified as drop-in and shelter-based. No studies measured the primary outcome of reintegration and none reported on adverse effects.We found no consistent results on a range of relevant outcomes within domains of psychosocial health, substance misuse and sexually risky behaviours . Interventions evaluated consisted of time-limited therapeutically based programmes that proved no more effective than standard shelter or drop-in services and other control interventions used for most outcomes in most studies. Favourable changes from baseline were reported for outcomes for most participants following therapy interventions and standard services. We noted considerable heterogeneity between studies and inconsistent reporting of equity data. No studies measured the primary outcome of reintegration or reported on adverse effects. Authors’ conclusions Analysis revealed no consistently significant benefit for focused therapeutic interventions compared with standard services such as dropin centres, case management and other comparable interventions for street-connected children and young people. Commonly available services, however, were not rigorously evaluated. Robust evaluation of interventions, including comparison with no intervention, would establish a more reliable evidence base to inform service implementation. More robust research is needed in LMICs to examine interventions for street-connected children and young people with different backgrounds and service needs

    Star Formation in the Trifid Nebula

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    We have obtained maps of the 1.25mm thermal dust emission and the molecular gas emission over a region of 20' by 10' arcmin around the Trifid Nebula (M20), with the IRAM 30m and the CSO telescopes as well as in the mid-infrared wavelength with ISO and SPITZER. Our survey is sensitive to features down to N(H2) \sim 10^{22} cm-2 in column density. The cloud material is distributed in fragmented dense gas filaments (n(H2) \sim 1000 cm-3) with sizes ranging from 1 to 10 pc. A massive filament, WF, with properties typical of Infra Red Dark Clouds, connects M20 to the W28 supernova remnant. These filaments pre-exist the formation of the Trifid and were originally self-gravitating. The fragments produced are very massive (100 Msun or more) and are the progenitors of the cometary globules observed at the border of the HII region. We could identify 33 cores, 16 of which are currently forming stars. They are usually gravitationally unbound and have low masses of a few Msun. The densest starless cores (several 10^5 cm-3) may be the site for the next generation of stars. The physical gas and dust properties of the cometary globules have been studied in detail and have been found very similar. They all are forming stars. Several intermediate-mass protostars have been detected in the cometary globules and in the deeply embedded cores. Evidence of clustering has been found in the shocked massive cores TC3-TC4-TC5. M20 is a good example of massive-star forming region in a turbulent, filamentary molecular cloud. Photoionization appears to play a minor role in the formation of the cores. The observed fragmentation is well explained by MHD-driven instabilities and is usually not related to M20. We propose that the nearby supernova remnant W28 could have triggered the formation of protostellar clusters in nearby dense cores of the Trifid.Comment: 16 pages, 24 figures, 5 Tables To appear in Astronomy and Astrophysic
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