24 research outputs found

    Upper limits to surface force disturbances on LISA proof masses and the possibility of observing galactic binaries

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    We report on the measurement of parasitic surface force noise on a hollow replica of a LISA (Laser Interferometer Space Antenna for the observation of gravitational waves) proof mass surrounded by a faithful representation of its in flight surroundings, namely the capacitive sensor used to detect proof-mass motion. Parasitic forces are detected through the corresponding torque exerted on the proof mass and measured with a torsion pendulum in the frequency range 0.1 30 mHz. The sensor electrodes, electrode housing and associated readout electronics have the same nominal design as for the flight hardware, including 4 mm gaps around the proof mass along the sensitive laser interferometry axis. We show that the measured upper limit for surface forces would allow detection of a number of galactic binaries signals with signal to noise ratio up to approximately 40 for 1 year integration. We also discuss how the flight test under development, LISA Pathfinder, will substantially improve this limit, approaching the performance required for LISA.Comment: 3 Figures. Submitted to Physical Review Letter

    Oneiric stress and safety and security at work: the discovery of a new universal symbol

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    Cox and Griffiths define as psychosocial risks at work “those aspects of the planning, organization and management of work, which, along with their environmental and social contexts, may affect mental and physical health of the employees, directly or indirectly producing stress”. Therefore, a more effective approach to occupational safety and security should include integrated risk management through the identification of any work stress related problem. The purpose of this paper is to analyze the possible correlation of risk at work with the modification of sleep, and inside it, the specific function of dream activity

    Sub-Femto- g Free Fall for Space-Based Gravitational Wave Observatories: LISA Pathfinder Results

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    We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2±0.1  fm s−2/Hz, or (0.54±0.01)×10−15  g/Hz, with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8±0.3)  fm/Hz, about 2 orders of magnitude better than requirements. At f≀0.5  mHz we observe a low-frequency tail that stays below 12  fm s−2/Hz down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.CNES 1316634/CNRS 103747UnivEarthS Labex program/ANR-10-LABX-0023UnivEarthS Labex program/ANR-11-IDEX-0005-02DLRFederal Ministry for Economic Affairs and Energy/FKZ 50OQ0501Federal Ministry for Economic Affairs and Energy/FKZ 50OQ1601Agenzia Spaziale ItalianaInstituto Nazionale di Fisica NucleareAYA2010-15709 (MICINN)ESP2013-47637-P (MINECO)ESP2015-67234-P (MINECO)Fundacion General CSICSwiss Space Office (SSO)Swiss National Science FoundationUnited Kingdom Space Agency (UKSA)University of GlasgowUniversity of BirminghamImperial CollegeScottish Universities Physics Alliance (SUPA)U.S. National Aeronautics and Space Administration (NASA

    Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

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    Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

    Diagnosis and management of Cornelia de Lange syndrome:first international consensus statement

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    Cornelia de Lange syndrome (CdLS) is an archetypical genetic syndrome that is characterized by intellectual disability, well-defined facial features, upper limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in any one of seven genes, all of which have a structural or regulatory function in the cohesin complex. Although recent advances in next-generation sequencing have improved molecular diagnostics, marked heterogeneity exists in clinical and molecular diagnostic approaches and care practices worldwide. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria, both for classic CdLS and non-classic CdLS phenotypes, molecular investigations, long-term management and care planning

    GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

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    Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment

    Thermal 1/f magnetic noise inCu 90 Co 10: effect of grain size

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    We report on the thermal magnetic noise with 1/f spectrum and the related a.c., linear response magnetic susceptibility measured at the liquid helium temperatures in the bulk granular systemCu 90 Co 10. The measurements has been performed on a set of samples where various particle size distributions of the nanostructured magnetic clusters has been produced through suitable annealing of the melt-spun ribbons. We report on the effect of the particle size distributions and barrier energy distributions on the magnetic linear regime viscous behavior

    Preparation of metal glasses by ion implantation and/or sputtering

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    NiSn and NiB metallic amorphous films were produced by ion-mixing and cosputter deposition.The present experimental results agree with an atomistic model for glass formation in samples undergoing energetic particle bombardment, based on spike formation and evolution
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