1,361 research outputs found

    Strong Bound on Canonical Ultralight Axion Dark Matter from the Lyman-Alpha Forest

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    We present a new bound on the ultralight axion (ULA) dark matter mass m a , using the Lyman-alpha forest to look for suppressed cosmic structure growth: a 95% lower limit m a > 2 × 10 − 20     eV . This strongly disfavors ( > 99.7 % credibility) the canonical ULA with 10 − 22     eV < m a < 10 − 21     eV , motivated by the string axiverse and solutions to possible tensions in the cold dark matter model. We strengthen previous equivalent bounds by about an order of magnitude. We demonstrate the robustness of our results using an optimized emulator of improved hydrodynamical simulations

    General framework for cosmological dark matter bounds using N-body simulations

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    We present a general framework for obtaining robust bounds on the nature of dark matter using cosmological N -body simulations and Lyman-alpha forest data. We construct an emulator of hydrodynamical simulations, which is a flexible, accurate and computationally efficient model for predicting the response of the Lyman-alpha forest flux power spectrum to different dark matter models, the state of the intergalactic medium (IGM) and the primordial power spectrum. The emulator combines a flexible parametrization for the small-scale suppression in the matter power spectrum arising in “noncold” dark matter models, with an improved IGM model. We then demonstrate how to optimize the emulator for the case of ultralight axion dark matter, presenting tests of convergence. We also carry out cross-validation tests of the accuracy of flux power spectrum prediction. This framework can be optimized for the analysis of many other dark matter candidates, e.g., warm or interacting dark matter. Our work demonstrates that a combination of an optimized emulator and cosmological “effective theories,” where many models are described by a single set of equations, is a powerful approach for robust and computationally efficient inference from the cosmic large-scale structure

    A clear view of the primordial Universe

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    Observations of temperature anisotropies in the cosmic microwave background (CMB) and measurements of the large-scale structure of matter have established the standard Lambda cold dark matter model of cosmology. Precise measurements of new observables will test extensions to the standard cosmological model, e.g., a non-zero tensor-to-scalar ratio of primordial perturbations, a running of the spectral index of the primordial power spectrum (both tests of cosmic inflation), or new components like massive neutrinos and warm dark matter (WDM). Two of the most promising observables to test these extensions in upcoming surveys are polarisation anisotropies in the CMB and correlations in the Lyman-alpha forest. Accurate cosmological parameter estimation, however, is only achievable through careful consideration of instrumental and astrophysical systematic effects, either by removing contamination in data or modelling its effect during statistical inference. I present new approaches to controlling contaminants to CMB temperature and polarisation and the Lyman-alpha forest. The primary contamination to the CMB is foreground Galactic radiation, e.g., synchrotron and thermal dust emission. I demonstrate the use of directional wavelets in more accurately reconstructing CMB temperature maps in the presence of these foregrounds, using Planck simulations and data. The complexity of polarised Galactic emissions limits constraints on inflation and neutrinos using CMB polarisation. I show how spin directional wavelets can allow additional morphological information to improve cosmic and foreground component separation. The Lyman-alpha forest probes the primordial power spectrum and the suppression of small-scale clustering by neutrinos or WDM. However, estimation of the shape of the power spectrum is biased by broadened absorption lines formed by high density systems of neutral hydrogen. I present models of their effect, built from Illustris cosmological hydrodynamical simulations. Being functions of absorber column density provides the flexibility to model residual contamination, after the largest absorbers have been removed from data

    The effectiveness of public health interventions to reduce the health impact of climate change:a systematic review of systematic reviews

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    Climate change is likely to be one of the most important threats to public health in the coming years. Yet despite the large number of papers considering the health impact of climate change, few have considered what public health interventions may be of most value in reducing the disease burden. We aimed to evaluate the effectiveness of public health interventions to reduce the disease burden of high priority climate sensitive diseases

    Kank Is an EB1 Interacting Protein that Localises to Muscle-Tendon Attachment Sites in Drosophila

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    Little is known about how microtubules are regulated in different cell types during development. EB1 plays a central role in the regulation of microtubule plus ends. It directly binds to microtubule plus ends and recruits proteins which regulate microtubule dynamics and behaviour. We report the identification of Kank, the sole Drosophila orthologue of human Kank proteins, as an EB1 interactor that predominantly localises to embryonic attachment sites between muscle and tendon cells. Human Kank1 was identified as a tumour suppressor and has documented roles in actin regulation and cell polarity in cultured mammalian cells. We found that Drosophila Kank binds EB1 directly and this interaction is essential for Kank localisation to microtubule plus ends in cultured cells. Kank protein is expressed throughout fly development and increases during embryogenesis. In late embryos, it accumulates to sites of attachment between muscle and epidermal cells. A kank deletion mutant was generated. We found that the mutant is viable and fertile without noticeable defects. Further analysis showed that Kank is dispensable for muscle function in larvae. This is in sharp contrast to C. elegans in which the Kank orthologue VAB-19 is required for development by stabilising attachment structures between muscle and epidermal cells

    Do adults with high functioning autism or Asperger Syndrome differ in empathy and emotion recognition?

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    The present study examined whether adults with high functioning autism (HFA) showed greater difficulties in (i) their self-reported ability to empathise with others and/or (ii) their ability to read mental states in others’ eyes than adults with Asperger syndrome (AS). The Empathy Quotient (EQ) and ‘Reading the Mind in the Eyes’ Test (Eyes Test) were compared in 43 adults with AS and 43 adults with HFA. No significant difference was observed on EQ score between groups, while adults with AS performed significantly better on the Eyes Test than those with HFA. This suggests that adults with HFA may need more support, particularly in mentalizing and complex emotion recognition, and raises questions about the existence of subgroups within autism spectrum conditions

    Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

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    The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition

    Search for Second-Generation Scalar Leptoquarks in ppˉ\bm{p \bar{p}} Collisions at s\sqrt{s}=1.96 TeV

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    Results on a search for pair production of second generation scalar leptoquark in ppˉp \bar{p} collisions at s\sqrt{s}=1.96 TeV are reported. The data analyzed were collected by the CDF detector during the 2002-2003 Tevatron Run II and correspond to an integrated luminosity of 198 pb1^{-1}. Leptoquarks (LQ) are sought through their decay into (charged) leptons and quarks, with final state signatures represented by two muons and jets and one muon, large transverse missing energy and jets. We observe no evidence for LQLQ production and derive 95% C.L. upper limits on the LQLQ production cross sections as well as lower limits on their mass as a function of β\beta, where β\beta is the branching fraction for LQμqLQ \to \mu q.Comment: 9 pages (3 author list) 5 figure

    Measurement of CP-violation asymmetries in D0 to Ks pi+ pi-

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    We report a measurement of time-integrated CP-violation asymmetries in the resonant substructure of the three-body decay D0 to Ks pi+ pi- using CDF II data corresponding to 6.0 invfb of integrated luminosity from Tevatron ppbar collisions at sqrt(s) = 1.96 TeV. The charm mesons used in this analysis come from D*+(2010) to D0 pi+ and D*-(2010) to D0bar pi-, where the production flavor of the charm meson is determined by the charge of the accompanying pion. We apply a Dalitz-amplitude analysis for the description of the dynamic decay structure and use two complementary approaches, namely a full Dalitz-plot fit employing the isobar model for the contributing resonances and a model-independent bin-by-bin comparison of the D0 and D0bar Dalitz plots. We find no CP-violation effects and measure an asymmetry of ACP = (-0.05 +- 0.57 (stat) +- 0.54 (syst))% for the overall integrated CP-violation asymmetry, consistent with the standard model prediction.Comment: 15 page
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