175 research outputs found

    Machine Learning for Quantum-Enhanced Gravitational-Wave Observatories

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    Machine learning has become an effective tool for processing the extensive data sets produced by large physics experiments. Gravitational-wave detectors are now listening to the universe with quantum-enhanced sensitivity, accomplished with the injection of squeezed vacuum states. Squeezed state preparation and injection is operationally complicated, as well as highly sensitive to environmental fluctuations and variations in the interferometer state. Achieving and maintaining optimal squeezing levels is a challenging problem and will require development of new techniques to reach the lofty targets set by design goals for future observing runs and next-generation detectors. We use machine learning techniques to predict the squeezing level during the third observing run of the Laser Interferometer Gravitational-Wave Observatory (LIGO) based on auxiliary data streams, and offer interpretations of our models to identify and quantify salient sources of squeezing degradation. The development of these techniques lays the groundwork for future efforts to optimize squeezed state injection in gravitational-wave detectors, with the goal of enabling closed-loop control of the squeezer subsystem by an agent based on machine learning

    Randomised controlled trial of a theory-based behavioural intervention to reduce formula milk intake

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    Objective: To assess the efficacy of a theory-based behavioural intervention to prevent rapidweight gain in formula-milk fed infants.  Design: In this single (assessor) blind, randomised controlled trial, 669 healthy full-terminfants receiving formula-milk within 14 weeks of birth were individually-randomised tointervention (n=340) or attention-matched control (n=329) groups. The intervention aimed toreduce formula-milk intakes, and promote responsive feeding and growth monitoring toprevent rapid weight gain (>+ 0.67 standard deviation scores [SDS]). It was delivered tomothers by trained facilitators up to infant age 6 months through 3 face-to-face contacts, 2telephone contacts, and written materials.  Results: Retention was 93% (622) at 6 months, 88% (586) at 12 months, and 94% attended >4/5 sessions. The intervention strengthened maternal attitudes to following infant feedingrecommendations, reduced reported milk intakes at ages 3 (-14%; intervention vs controlinfants), 4 (-12%), 5 (-9%), and 6 (-7%) months, slowed initial infant weight gain frombaseline to 6 months (mean change 0.32 vs 0.42 SDS, baseline-adjusted difference(intervention vs control) -0.08 [95% CI; -0.17, -0.004] SDS), but had no effect on the primaryoutcome of weight gain to 12 months (baseline-adjusted difference -0.04 [-0.17, 0.10] SDS).By 12 months, 40.3% of infants in the intervention group and 45.9% in the control groupshowed rapid weight gain (OR: 0.84 [95% CI; 0.59, 1.17]).  Conclusions: Despite reducing milk intakes and initial weight gain, the intervention did notalter the high prevalence of rapid weight gain to age 12 months suggesting the need forsustained intervention

    Study protocol: imaging brain development in the Childhood to Adolescence Transition Study (iCATS)

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    BackgroundPuberty is a critical developmental phase in physical, reproductive and socio-emotional maturation that is associated with the period of peak onset for psychopathology. Puberty also drives significant changes in brain development and function. Research to date has focused on gonadarche, driven by the hypothalamic-pituitary-gonadal axis, and yet increasing evidence suggests that the earlier pubertal stage of adrenarche, driven by the hypothalamic-pituitary-adrenal axis, may play a critical role in both brain development and increased risk for disorder. We have established a unique cohort of children who differ in their exposure to adrenarcheal hormones. This presents a unique opportunity to examine the influence of adrenarcheal timing on brain structural and functional development, and subsequent health outcomes. The primary objective of the study is to explore the hypothesis that patterns of structural and functional brain development will mediate the relationship between adrenarcheal timing and indices of affect, self-regulation, and mental health symptoms collected across time (and therefore years of development).Methods/DesignChildren were recruited based upon earlier or later timing of adrenarche, from a larger cohort, with 128 children (68 female; M age 9.51 years) and one of their parents taking part. Children completed brain MRI structural and functional sequences, provided saliva samples for adrenarcheal hormones and immune biomarkers, hair for long-term cortisol levels, and completed questionnaires, anthropometric measures and an IQ test. Parents completed questionnaires reporting on child behaviour, development, health, traumatic events, and parental report of family environment and parenting style.DiscussionThis study, by examining the neurobiological and behavioural consequences of relatively early and late exposure to adrenarche, has the potential to significantly impact our understanding of pubertal risk processes.<br /

    CONSERVATION OF THE ORINOCO GOOSE (NEOCHEN JUBATA) IN THE MIDDLE ARAGUAIA RIVER, TOCANTINS, BRAZIL.

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    The Orinoco goose, (Neochen jubata) is a grazing herbivore of open habitats that was once widely distributed in tropical South America. Centuries of overhunting and habitat loss have reduced it to widely scattered remnant populations; it is categorized as Near Threatened globally. Within the Cerrado biome, the Middle Araguaia River houses the largest remnant population. In August 2017, a study was started to assess the situation of the Orinoco Goose in the regions of Araguaia National Park, Cantão State Park, and adjacent rice fields. We conducted counts from an aerial census (a 700 km transect), monthly boat censuses (40 km) and land censuses in rice plantations. The aircraft census counted 367 individuals in August 2017, while monthly monitoring of a stretch of the lower Javaés River over more than two years showed a seasonal population variation associated with the flood regime, with the species virtually disappearing during the flood period between January and April when river beaches are submerged. During this period, large flocks of about 1,000 Orinoco Geese were discovered not far away, concentrated in small stretches of rice plantation agro-systems in the region.  This behavioral seasonal concentration makes the species susceptible to poisoning and epizootic diseases. The findings suggest the need to re-categorize the Orinoco Goose population of the Middle Araguaia River as “Threatened” for the State of Tocantins due to the decline observed in the last 10 years, the maximum estimated population size, and the significant seasonal concentrations in a restricted area. At the same time, it is necessary to develop an action plan for its conservation in the surroundings of Ilha do Bananal, and throughout Brazil, where its threat status must be reviewed

    Re-structuring of marine communities exposed to environmental change

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    Species richness is the most commonly used but controversial biodiversity metric in studies on aspects of community stability such as structural composition or productivity. The apparent ambiguity of theoretical and experimental findings may in part be due to experimental shortcomings and/or heterogeneity of scales and methods in earlier studies. This has led to an urgent call for improved and more realistic experiments. In a series of experiments replicated at a global scale we translocated several hundred marine hard bottom communities to new environments simulating a rapid but moderate environmental change. Subsequently, we measured their rate of compositional change (re-structuring) which in the great majority of cases represented a compositional convergence towards local communities. Re-structuring is driven by mortality of community components (original species) and establishment of new species in the changed environmental context. The rate of this re-structuring was then related to various system properties. We show that availability of free substratum relates negatively while taxon richness relates positively to structural persistence (i.e., no or slow re-structuring). Thus, when faced with environmental change, taxon-rich communities retain their original composition longer than taxon-poor communities. The effect of taxon richness, however, interacts with another aspect of diversity, functional richness. Indeed, taxon richness relates positively to persistence in functionally depauperate communities, but not in functionally diverse communities. The interaction between taxonomic and functional diversity with regard to the behaviour of communities exposed to environmental stress may help understand some of the seemingly contrasting findings of past research

    Unlocking the bottleneck in forward genetics using whole-genome sequencing and identity by descent to isolate causative mutations

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    Forward genetics screens with N-ethyl-N-nitrosourea (ENU) provide a powerful way to illuminate gene function and generate mouse models of human disease; however, the identification of causative mutations remains a limiting step. Current strategies depend on conventional mapping, so the propagation of affected mice requires non-lethal screens; accurate tracking of phenotypes through pedigrees is complex and uncertain; out-crossing can introduce unexpected modifiers; and Sanger sequencing of candidate genes is inefficient. Here we show how these problems can be efficiently overcome using whole-genome sequencing (WGS) to detect the ENU mutations and then identify regions that are identical by descent (IBD) in multiple affected mice. In this strategy, we use a modification of the Lander-Green algorithm to isolate causative recessive and dominant mutations, even at low coverage, on a pure strain background. Analysis of the IBD regions also allows us to calculate the ENU mutation rate (1.54 mutations per Mb) and to model future strategies for genetic screens in mice. The introduction of this approach will accelerate the discovery of causal variants, permit broader and more informative lethal screens to be used, reduce animal costs, and herald a new era for ENU mutagenesis.The High-Throughput Genomics Group at the Wellcome Trust Centre for Human Genetics is funded by Wellcome Trust grant reference 090532/Z/09/Z and MRC Hub grant G0900747 91070. This study was supported by Wellcome Trust Strategic Award 082030 (CCG), Wellcome Trust Studentship 094446/Z/10/Z (KRB), the Oxford NIHR Biomedical Research Centre, and the MRC Human Immunology Unit (RJC). AJR and GL were supported by Wellcome Trust grant 090532/Z/ 09/Z, CCG and AE by a Major initiative Award from the Clive and Vera Ramaciotti Foundation, and AE by an NHMRC Career Development Award. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    B cell survival, surface BCR and BAFFR expression, CD74 metabolism, and CD8-dendritic cells require the intramembrane endopeptidase SPPL2A

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    Druggable proteins required for B lymphocyte survival and immune responses are an emerging source of new treatments for autoimmunity and lymphoid malignancy. In this study, we show that mice with an inactivating mutation in the intramembrane protease signal peptide peptidase-like 2A (SPPL2A) unexpectedly exhibit profound humoral immunodeficiency and lack mature B cell subsets, mirroring deficiency of the cytokine B cell-activating factor (BAFF). Accumulation of Sppl2a-deficient B cells was rescued by overexpression of the BAFF-induced survival protein B cell lymphoma 2 (BCL2) but not BAFF and was distinguished by low surface BAFF receptor and IgM and IgD B cell receptors. CD8-negative dendritic cells were also greatly decreased. SPPL2A deficiency blocked the proteolytic processing of CD74 MHC II invariant chain in both cell types, causing dramatic build-up of the p8 product of Cathepsin S and interfering with earlier steps in CD74 endosomal retention and processing. The findings illuminate an important role for the final step in the CD74-MHC II pathway and a new target for protease inhibitor treatment of B cell diseases.R01 AI052127/AI/NIAID NIH HHS/United States U19 AI100627/AI/NIAID NIH HHS/United States Medical Research Council/United Kingdom Wellcome Trust/United Kingdo
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