163 research outputs found
Cosmology at the Millennium
One hundred years ago we did not know how stars generate energy, the age of
the Universe was thought to be only millions of years, and our Milky Way galaxy
was the only galaxy known. Today, we know that we live in an evolving and
expanding Universe comprising billions of galaxies, all held together by dark
matter. With the hot big-bang model, we can trace the evolution of the Universe
from the hot soup of quarks and leptons that existed a fraction of a second
after the beginning to the formation of galaxies a few billion years later, and
finally to the Universe we see today 13 billion years after the big bang, with
its clusters of galaxies, superclusters, voids, and great walls. The attractive
force of gravity acting on tiny primeval inhomogeneities in the distribution of
matter gave rise to all the structure seen today. A paradigm based upon deep
connections between cosmology and elementary particle physics -- inflation +
cold dark matter -- holds the promise of extending our understanding to an even
more fundamental level and much earlier times, as well as shedding light on the
unification of the forces and particles of nature. As we enter the 21st
century, a flood of observations is testing this paradigm.Comment: 44 pages LaTeX with 14 eps figures. To be published in the Centennial
Volume of Reviews of Modern Physic
Accuracy of self-reported breast cancer among women undergoing mammography
This study estimated the sensitivity and specificity of self-reported breast cancer and their associations with patient factors and pathologic findings using data from the Breast Cancer Surveillance Consortium
Is the evidence for dark energy secure?
Several kinds of astronomical observations, interpreted in the framework of
the standard Friedmann-Robertson-Walker cosmology, have indicated that our
universe is dominated by a Cosmological Constant. The dimming of distant Type
Ia supernovae suggests that the expansion rate is accelerating, as if driven by
vacuum energy, and this has been indirectly substantiated through studies of
angular anisotropies in the cosmic microwave background (CMB) and of spatial
correlations in the large-scale structure (LSS) of galaxies. However there is
no compelling direct evidence yet for (the dynamical effects of) dark energy.
The precision CMB data can be equally well fitted without dark energy if the
spectrum of primordial density fluctuations is not quite scale-free and if the
Hubble constant is lower globally than its locally measured value. The LSS data
can also be satisfactorily fitted if there is a small component of hot dark
matter, as would be provided by neutrinos of mass 0.5 eV. Although such an
Einstein-de Sitter model cannot explain the SNe Ia Hubble diagram or the
position of the `baryon acoustic oscillation' peak in the autocorrelation
function of galaxies, it may be possible to do so e.g. in an inhomogeneous
Lemaitre-Tolman-Bondi cosmology where we are located in a void which is
expanding faster than the average. Such alternatives may seem contrived but
this must be weighed against our lack of any fundamental understanding of the
inferred tiny energy scale of the dark energy. It may well be an artifact of an
oversimplified cosmological model, rather than having physical reality.Comment: 12 pages, 5 figures; to appear in a special issue of General
Relativity and Gravitation, eds. G.F.R. Ellis et al; Changes: references
reformatted in journal style - text unchange
The founding charter of the Genomic Observatories Network
The co-authors of this paper hereby state their intention to work together to launch the Genomic Observatories Network (GOs Network) for which this document will serve as its Founding Charter. We define a Genomic Observatory as an ecosystem and/or site subject to long-term scientific research, including (but not limited to) the sustained study of genomic biodiversity from single-celled microbes to multicellular organisms.An international group of 64 scientists first published the call for a global network of Genomic Observatories in January 2012. The vision for such a network was expanded in a subsequent paper and developed over a series of meetings in Bremen (Germany), Shenzhen (China), Moorea (French Polynesia), Oxford (UK), Pacific Grove (California, USA), Washington (DC, USA), and London (UK). While this community-building process continues, here we express our mutual intent to establish the GOs Network formally, and to describe our shared vision for its future. The views expressed here are ours alone as individual scientists, and do not necessarily represent those of the institutions with which we are affiliated.Neil Davies ... Andrew J Lowe ... et al. and GOs-CO
Transmission of SARS and MERS coronaviruses and influenza virus in healthcare settings: the possible role of dry surface contamination
Viruses with pandemic potential including H1N1, H5N1, and H5N7 influenza viruses, and severe acute respiratory syndrome (SARS)/Middle East respiratory syndrome (MERS) coronaviruses (CoV) have emerged in recent years. SARS-CoV, MERS-CoV, and influenza virus can survive on surfaces for extended periods, sometimes up to months. Factors influencing the survival of these viruses on surfaces include: strain variation, titre, surface type, suspending medium, mode of deposition, temperature and relative humidity, and the method used to determine the viability of the virus. Environmental sampling has identified contamination in field-settings with SARS-CoV and influenza virus, although the frequent use of molecular detection methods may not necessarily represent the presence of viable virus. The importance of indirect contact transmission (involving contamination of inanimate surfaces) is uncertain compared with other transmission routes, principally direct contact transmission (independent of surface contamination), droplet, and airborne routes. However, influenza virus and SARS-CoV may be shed into the environment and be transferred from environmental surfaces to hands of patients and healthcare providers. Emerging data suggest that MERS-CoV also shares these properties. Once contaminated from the environment, hands can then initiate self-inoculation of mucous membranes of the nose, eyes or mouth. Mathematical and animal models, and intervention studies suggest that contact transmission is the most important route in some scenarios. Infection prevention and control implications include the need for hand hygiene and personal protective equipment to minimize self-contamination and to protect against inoculation of mucosal surfaces and the respiratory tract, and enhanced surface cleaning and disinfection in healthcare settings
Rare variants with large effects provide functional insights into the pathology of migraine subtypes, with and without aura
Publisher Copyright: © 2023, The Author(s).Migraine is a complex neurovascular disease with a range of severity and symptoms, yet mostly studied as one phenotype in genome-wide association studies (GWAS). Here we combine large GWAS datasets from six European populations to study the main migraine subtypes, migraine with aura (MA) and migraine without aura (MO). We identified four new MA-associated variants (in PRRT2, PALMD, ABO and LRRK2) and classified 13 MO-associated variants. Rare variants with large effects highlight three genes. A rare frameshift variant in brain-expressed PRRT2 confers large risk of MA and epilepsy, but not MO. A burden test of rare loss-of-function variants in SCN11A, encoding a neuron-expressed sodium channel with a key role in pain sensation, shows strong protection against migraine. Finally, a rare variant with cis-regulatory effects on KCNK5 confers large protection against migraine and brain aneurysms. Our findings offer new insights with therapeutic potential into the complex biology of migraine and its subtypes.Peer reviewe
Partitioning the Heritability of Tourette Syndrome and Obsessive Compulsive Disorder Reveals Differences in Genetic Architecture
The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease explained
The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape : A Large-Scale Genome-Wide Interaction Study
Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age-and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to similar to 2.8M SNPs with BMI and WHRadjBMI in four strata (men 50y, women 50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR= 50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may providefurther insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.Peer reviewe
- …