3,399 research outputs found

    Power-law random walks

    Full text link
    We present some new results about the distribution of a random walk whose independent steps follow a qq-Gaussian distribution with exponent 11q;qR\frac{1}{1-q}; q \in \mathbb{R}. In the case q>1q>1 we show that a stochastic representation of the point reached after nn steps of the walk can be expressed explicitly for all nn. In the case q<1,q<1, we show that the random walk can be interpreted as a projection of an isotropic random walk, i.e. a random walk with fixed length steps and uniformly distributed directions.Comment: 5 pages, 4 figure

    Risk of All-Cause Mortality in Alcohol-Dependent Individuals: A Systematic Literature Review and Meta-Analysis.

    Get PDF
    BACKGROUND: Alcohol dependence (AD) carries a high mortality burden, which may be mitigated by reduced alcohol consumption. We conducted a systematic literature review and meta-analysis investigating the risk of all-cause mortality in alcohol-dependent subjects. METHODS: MEDLINE, MEDLINE In-Process, Embase and PsycINFO were searched from database conception through 26th June 2014. Eligible studies reported all-cause mortality in both alcohol-dependent subjects and a comparator population of interest. Two individuals independently reviewed studies. Of 4540 records identified, 39 observational studies were included in meta-analyses. FINDINGS: We identified a significant increase in mortality for alcohol-dependent subjects compared with the general population (27 studies; relative risk [RR] = 3.45; 95% CI [2.96, 4.02]; p &lt; 0.0001). The mortality increase was also significant compared to subjects qualifying for a diagnosis of alcohol abuse or subjects without alcohol use disorders (AUDs). Alcohol-dependent subjects continuing to drink heavily had significantly greater mortality than alcohol-dependent subjects who reduced alcohol intake, even if abstainers were excluded (p &lt; 0.05). INTERPRETATION: AD was found to significantly increase an individual's risk of all-cause mortality. While abstinence in alcohol-dependent subjects led to greater mortality reduction than non-abstinence, this study suggests that alcohol-dependent subjects can significantly reduce their mortality risk by reducing alcohol consumption

    The value of habitats of conservation importance to climate change mitigation in the UK

    Get PDF
    The input of PS contributes to the following UKRI-funded projects: DEVIL (NE/M021327/1) and Soils-R-GRREAT (NE/P019455/1). The contributions of RHF, GMB, AH and RBB were funded by RSPB. Thanks to Olly Watts and Phil Grice and three anonymous reviewers for comments on earlier versions of this paper, their comments immeasurably improved it. Thanks also to Ruth Davies, Mel Coath, Vicki Swales, Arfon Williams, Tom Lancaster, Andrew Midgely, Phillip Carson, Jonathan Cryer, Adam Barnett, Paul Morling, Pat Thompson, Beatriz Luraschi, Kate Jennings and Jonathon Bell who helped frame the question addressed here and shape the ‘storymap’ based on this work, available at https://arcg.is/098uiD.Peer reviewedPostprin

    The extent and effectiveness of protected areas in the UK

    Get PDF
    The Convention on Biological Diversity (CBD), to which 196 countries including the UK are contracting parties, set out 20 Aichi Biodiversity Targets to be met by 2020. Elements of Aichi Target 11 call for at least 17% of terrestrial land and inland water to be protected and effectively managed by 2020. Each national government is requested to report progress against this goal in national reports submitted at intervals to the CBD, and these are used as the basis of reporting towards the 17% target. Figures reported for the UK’s protected area coverage are inclusive of a wide range of levels of designation, management and condition. Here, we examine the protection given to sites under UK legislation and designations as a case study. We find that although 28% of UK land is reported by the UK government to be protected, only 11.4% of land area falls within protected areas designated primarily for nature conservation. Condition monitoring indicates that at most 43–51% of protected areas in the UK are currently in favourable condition, which suggests as little as 4.9% of UK land area may be effectively protected for nature. However, estimates of protected area coverage vary greatly depending on the types of protected areas considered ‘effectively protected’ as measured by management category and site condition. Taking the UK as an example of a country that has reportedly met the target, we suggest that global progress may have been overestimated, and that future targets and indicators need to focus on the quality as well as quantity of protected areas

    High-resolution temporal profiling of transcripts during Arabidopsis leaf senescence reveals a distinct chronology of processes and regulation

    Get PDF
    Leaf senescence is an essential developmental process that impacts dramatically on crop yields and involves altered regulation of thousands of genes and many metabolic and signaling pathways, resulting in major changes in the leaf. The regulation of senescence is complex, and although senescence regulatory genes have been characterized, there is little information on how these function in the global control of the process. We used microarray analysis to obtain a highresolution time-course profile of gene expression during development of a single leaf over a 3-week period to senescence. A complex experimental design approach and a combination of methods were used to extract high-quality replicated data and to identify differentially expressed genes. The multiple time points enable the use of highly informative clustering to reveal distinct time points at which signaling and metabolic pathways change. Analysis of motif enrichment, as well as comparison of transcription factor (TF) families showing altered expression over the time course, identify clear groups of TFs active at different stages of leaf development and senescence. These data enable connection of metabolic processes, signaling pathways, and specific TF activity, which will underpin the development of network models to elucidate the process of senescence

    Luminosities and mass-loss rates of SMC and LMC AGB stars and Red Supergiants

    Full text link
    (Abridged) Dust radiative transfer models are presented for 101 carbon stars and 86 oxygen-rich evolved stars in the Magellanic Clouds for which 5-35 \mum\ {\it Spitzer} IRS spectra are available. The spectra are complemented with available optical and infrared photometry to construct the spectral energy distribution. A minimisation procedure is used to fit luminosity, mass-loss rate and dust temperature at the inner radius. Different effective temperatures and dust content are also considered. Periods from the literature and from new OGLE-III data are compiled and derived. The O-rich stars are classified in foreground objects, AGB stars and Red Super Giants. For the O-rich stars silicates based on laboratory optical constants are compared to "astronomical silicates". Overall, the grain type by Volk & Kwok (1988) fit the data best. However, the fit based on laboratory optical constants for the grains can be improved by abandoning the small-particle limit. The influence of grain size, core-mantle grains and porosity are explored. Relations between mass-loss rates and luminosity and pulsation period are presented and compared to the predictions of evolutionary models, those by Vassiliadis & Wood (1993) and their adopted mass-loss recipe, and those based on a Reimers mass-loss law with a scaling of a factor of five. The Vassiliadis & Wood models describe the data better, although there are also some deficiencies, in particular to the maximum adopted mass-loss rate. The OGLE-III data reveal an O-rich star in the SMC with a period of 1749 days. Its absolute magnitude of Mbol=8.0M_{\rm bol}= -8.0 makes it a good candidate for a super-AGB star.Comment: A&A accepte

    A single-center, observational study of 607 children & young people presenting with Differences in Sex Development (DSD)

    Get PDF
    Context Differences in sex development (DSD) represent a wide range of conditions presenting at different ages to various health professionals. Establishing a diagnosis, supporting the family and developing a management plan are important. Objective We aimed to better understand the presentation and prevalence of pediatric DSD. Design A retrospective, observational cohort study was undertaken of all children and young people (CYP) referred to a DSD multi-disciplinary team over 25 years (1995-2019). Setting A single tertiary paediatric center. Participants In total, 607 CYP (520 regional referrals) were included. Main Outcome Measures Data were analyzed for diagnosis, sex-assignment, age and mode of presentation, additional phenotypic features, mortality, and approximate point prevalence. Results Amongst the three major DSD categories, sex chromosome DSD was diagnosed in 11.2% (68/607) (most commonly 45, X/46, XY mosaicism), 46, XY DSD in 61.1% (371/607) (multiple diagnoses often with associated features), while 46, XX DSD occurred in 27.7% (168/607) (often 21-hydroxylase deficiency). Most children (80.1%) presented as neonates, usually with atypical genitalia, adrenal insufficiency, undescended testes or herniae. Those presenting later had diverse features. Rarely, the diagnosis was made antenatally (3.8%, n = 23) or following incidental karyotyping/family history (n = 14). Mortality was surprisingly high in 46, XY children, usually due to complex associated features (46, XY girls, 8.3%; 46, XY boys, 2.7%). The approximate point prevalence of neonatal referrals for investigation of DSD was 1 in 6,347 births, and 1 in 5,101 overall throughout childhood. Conclusions DSD represent a diverse range of conditions that can present at different ages. Pathways for expert diagnosis and management are important to optimize care

    Developing reading-writing connections; the impact of explicit instruction of literary devices on the quality of children's narrative writing

    Get PDF
    The purpose of this collaborative schools-university study was to investigate how the explicit instruction of literary devices during designated literacy sessions could improve the quality of children's narrative writing. A guiding question for the study was: Can children's writing can be enhanced by teachers drawing attention to the literary devices used by professional writers or “mentor authors”? The study was conducted with 18 teachers, working as research partners in nine elementary schools over one school year. The research group explored ways of developing children as reflective authors, able to draft and redraft writing in response to peer and teacher feedback. Daily literacy sessions were complemented by weekly writing workshops where students engaged in authorial activity and experienced writers' perspectives and readers' demands (Harwayne, 1992; May, 2004). Methods for data collection included video recording of peer-peer and teacher-led group discussions and audio recording of teacher-child conferences. Samples of children's narrative writing were collected and a comparison was made between the quality of their independent writing at the beginning and end of the research period. The research group documented the importance of peer-peer and teacher-student discourse in the development of children's metalanguage and awareness of audience. The study suggests that reading, discussing, and evaluating mentor texts can have a positive impact on the quality of children's independent writing
    corecore