1,065 research outputs found
The Extended Baryon Oscillation Spectroscopic Survey: Variability Selection and Quasar Luminosity Function
The SDSS-IV/eBOSS has an extensive quasar program that combines several
selection methods. Among these, the photometric variability technique provides
highly uniform samples, unaffected by the redshift bias of traditional
optical-color selections, when quasars cross the stellar locus
or when host galaxy light affects quasar colors at . Here, we present
the variability selection of quasars in eBOSS, focusing on a specific program
that led to a sample of 13,876 quasars to over a 94.5
deg region in Stripe 82, an areal density 1.5 times higher than over the
rest of the eBOSS footprint. We use these variability-selected data to provide
a new measurement of the quasar luminosity function (QLF) in the redshift range
. Our sample is denser, reaches deeper than those used in previous
studies of the QLF, and is among the largest ones. At the faint end, our QLF
extends to at low redshift and to
at . We fit the QLF using two independent double-power-law models with
ten free parameters each. The first model is a pure luminosity-function
evolution (PLE) with bright-end and faint-end slopes allowed to be different on
either side of . The other is a simple PLE at , combined with a
model that comprises both luminosity and density evolution (LEDE) at .
Both models are constrained to be continuous at . They present a
flattening of the bright-end slope at large redshift. The LEDE model indicates
a reduction of the break density with increasing redshift, but the evolution of
the break magnitude depends on the parameterization. The models are in
excellent accord, predicting quasar counts that agree within 0.3\% (resp.,
1.1\%) to (resp., ). The models are also in good agreement over
the entire redshift range with models from previous studies.Comment: 15 pages, 12 figures, accepted for publication in A&
Constraints on the Neutrino Mass from SZ Surveys
Statistical measures of galaxy clusters are sensitive to neutrino masses in
the sub-eV range. We explore the possibility of using cluster number counts
from the ongoing PLANCK/SZ and future cosmic-variance-limited surveys to
constrain neutrino masses from CMB data alone. The precision with which the
total neutrino mass can be determined from SZ number counts is limited mostly
by uncertainties in the cluster mass function and intracluster gas evolution;
these are explicitly accounted for in our analysis. We find that projected
results from the PLANCK/SZ survey can be used to determine the total neutrino
mass with a (1\sigma) uncertainty of 0.06 eV, assuming it is in the range
0.1-0.3 eV, and the survey detection limit is set at the 5\sigma significance
level. Our results constitute a significant improvement on the limits expected
from PLANCK/CMB lensing measurements, 0.15 eV. Based on expected results from
future cosmic-variance-limited (CVL) SZ survey we predict a 1\sigma uncertainty
of 0.04 eV, a level comparable to that expected when CMB lensing extraction is
carried out with the same experiment. A few percent uncertainty in the mass
function parameters could result in up to a factor \sim 2-3 degradation of our
PLANCK and CVL forecasts. Our analysis shows that cluster number counts provide
a viable complementary cosmological probe to CMB lensing constraints on the
total neutrino mass.Comment: Replaced with a revised version to match the MNRAS accepted version.
arXiv admin note: text overlap with arXiv:1009.411
HL-1 cells express an inwardly rectifying K+ current activated via muscarinic receptors comparable to that in mouse atrial myocytes
An inwardly rectifying K^+ current is present in atrial cardiac myocytes that is activated by acetylcholine (I_{KACh}). Physiologically, activation of the current in the SA node is important in slowing the heart rate with increased parasympathetic tone. It is a paradigm for the direct regulation of signaling effectors by the Gβγ G-protein subunit. Many questions have been addressed in heterologous expression systems with less focus on the behaviour in native myocytes partly because of the technical difficulties in undertaking comparable studies in native cells. In this study, we characterise a potassium current in the atrial-derived cell line HL-1. Using an electrophysiological approach, we compare the characteristics of the potassium current with those in native atrial cells and in a HEK cell line expressing the cloned Kir3.1/3.4 channel. The potassium current recorded in HL-1 is inwardly rectifying and activated by the muscarinic agonist carbachol. Carbachol-activated currents were inhibited by pertussis toxin and tertiapin-Q. The basal current was time-dependently increased when GTP was substituted in the patch-clamp pipette by the non-hydrolysable analogue GTPγS. We compared the kinetics of current modulation in HL-1 with those of freshly isolated atrial mouse cardiomyocytes. The current activation and deactivation kinetics in HL-1 cells are comparable to those measured in atrial cardiomyocytes. Using immunofluorescence, we found GIRK4 at the membrane in HL-1 cells. Real-time RT-PCR confirms the presence of mRNA for the main G-protein subunits, as well as for M2 muscarinic and A1 adenosine receptors. The data suggest HL-1 cells are a good model to study IKAch
A fitting formula for the non-Gaussian contribution to the lensing power spectrum covariance
Weak gravitational lensing is one of the most promising tools to investigate
the equation-of-state of dark energy. In order to obtain reliable parameter
estimations for current and future experiments, a good theoretical
understanding of dark matter clustering is essential. Of particular interest is
the statistical precision to which weak lensing observables, such as cosmic
shear correlation functions, can be determined. We construct a fitting formula
for the non-Gaussian part of the covariance of the lensing power spectrum. The
Gaussian contribution to the covariance, which is proportional to the lensing
power spectrum squared, and optionally shape noise can be included easily by
adding their contributions. Starting from a canonical estimator for the
dimensionless lensing power spectrum, we model first the covariance in the halo
model approach including all four halo terms for one fiducial cosmology and
then fit two polynomials to the expression found. On large scales, we use a
first-order polynomial in the wave-numbers and dimensionless power spectra that
goes asymptotically towards for , i.e., the result for
the non-Gaussian part of the covariance using tree-level perturbation theory.
On the other hand, for small scales we employ a second-order polynomial in the
dimensionless power spectra for the fit. We obtain a fitting formula for the
non-Gaussian contribution of the convergence power spectrum covariance that is
accurate to 10% for the off-diagonal elements, and to 5% for the diagonal
elements, in the range and can be used for
single source redshifts in WMAP5-like cosmologies.Comment: 23 pages, 15 figures, submitted to A&
Temperature
KEY HEADLINES: • The first MCCIP ARC in 2006 reported following what was then the warmest year globally in 2005 (0.26°C higher than the 1981-2010 average). • Since 2005, new global record temperatures have been set in 2010 and then in each successive year 2014, 2015 and 2016. In these last three record years the global average temperature anomaly was 0.31,0.44, 0.56°C higher than the 1981-2010 average. • 2014 was a record warm year for coastal air and sea temperatures around the UK. Between 1984 and 2014 coastal water temperatures rose around the UK at an average rate of 0.28 °C/decade. The rate varies between regions, the slowest warming was in the Celtic Sea at 0.17 °C/decade and the maximum rate was in the Southern North Sea at 0.45 °C/decade. • There is also variability over shorter time periods. In all regions of UK seas there was a negative trend in the 10-year period between 2003 and 2013. This is due to variability within the ocean /atmosphere system which is natural. • There is a trend towards fewer in-situ observations, and this will ultimately influence the confidence in future assessments. • Some gridded datasets can offer alternatives to single point observations, but to understand the patterns of ocean variability, the quality information from ocean timeseries cannot yet be replaced by surface observations or autonomous data collection. • The first MCCIP report card in 2006 used the UKCIP projections from 2002 which had a very limited representation of the SST. • The latest updates to the UK Climate Projections shelf seas models were published in 2016 and projected increases in sea surface temperature for 2069-89 relative to 1960-89 of over 3 °C for most of the North Sea, English Channel, Irish and Celtic Seas. For the deeper areas to the north and west of Scotland out towards Rockall and in the Faroe Shetland Channel the increase in temperature is projected to be closer to 2 °C. • Over the last 10 years there has been a steady improvement in the scientific basis underlying centennial sea temperature projections for the seas around the UK, and significant progress in the field of seasonal and decadal projections. • The scientific basis to such projections and predictions will continue to improve over the next 10 years, with increasing resolution, treatment of climate uncertainties, and methodology. Over the centennial scale the difference between emissions scenarios are still the source of the largest uncertainties. • Development of North West European Shelf (NWS) modelling systems driven by seasonal forecasting systems may allow NWS temperature prediction over the monthly to decadal period
Corporate Social Responsibility and Islamic Financial Institutions (IFIs): Management Perceptions from IFIs in Bahrain
Islamic finance is gaining greater attention in the finance industry, and this paper analyses how Islamic financial institutions (IFIs) are responding to the welfare needs of society. Using interview data with managers and content analysis of the disclosures, this study attempts to understand management perceptions of corporate social
responsibility (CSR) in IFIs. A thorough understanding of CSR by managers, as evident in the interviews, has not been translated fully into practice. The partial use of IFIs’ potential role in social welfare would add further challenges in the era of financialisation
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Letter processing and font information during reading: beyond distinctiveness, where vision meets design
Letter identification is a critical front end of the
reading process. In general, conceptualizations of the identification process have emphasized arbitrary sets of distinctive features. However, a richer view of letter processing incorporates principles from the field of type design, including an emphasis on uniformities across letters within a font. The importance of uniformities is supported by a small body of research indicating that consistency of font increases letter identification efficiency. We review design concepts and the relevant literature, with the goal of stimulating further thinking about letter processing during reading
Secondary somatic mutations restoring RAD51C and RAD51D associated with acquired resistance to the PARP inhibitor rucaparib in high-grade ovarian carcinoma
High-grade epithelial ovarian carcinomas (OC) containing mutated BRCA1 or BRCA2 (BRCA1/2) homologous recombination (HR) genes are sensitive to platinum-based chemotherapy and poly(ADP-ribose) polymerase inhibitors (PARPi), while restoration of HR function due to secondary mutations in BRCA1/2 has been recognized as an important resistance mechanism. We sequenced core HR pathway genes in 12 pairs of pre-treatment and post-progression tumor biopsy samples collected from patients in ARIEL2 Part 1, a phase 2 study of the PARPi rucaparib as treatment for platinum-sensitive, relapsed OC. In six of 12 pre-treatment biopsies, a truncation mutation in BRCA1, RAD51C or RAD51D was identified. In five of six paired post-progression biopsies, one or more secondary mutations restored the open reading frame. Four distinct secondary mutations and spatial heterogeneity were observed for RAD51C. In vitro complementation assays and a patient-derived xenograft (PDX), as well as predictive molecular modeling, confirmed that resistance to rucaparib was associated with secondary mutations
The Sloan Great Wall. Morphology and galaxy content
We present the results of the study of the morphology and galaxy content of
the Sloan Great Wall (SGW). We use the luminosity density field to determine
superclusters in the SGW, and the fourth Minkowski functional V_3 and the
morphological signature (the K_1-K_2 shapefinders curve) to show the different
morphologies of the SGW, from a single filament to a multibranching, clumpy
planar system. The richest supercluster in the SGW, SCl~126 and especially its
core resemble a very rich filament, while another rich supercluster in the SGW,
SCl~111, resembles a "multispider" - an assembly of high density regions
connected by chains of galaxies. Using Minkowski functionals we study the
substructure of individual galaxy populations determined by their color in
these superclusters. We assess the statistical significance of the results with
the halo model and smoothed bootstrap. We study the galaxy content and the
properties of groups of galaxies in two richest superclusters of the SGW,
paying special attention to bright red galaxies (BRGs) and to the first ranked
galaxies in SGW groups. About 1/3 of BRGs are spirals. The scatter of colors of
elliptical BRGs is smaller than that of spiral BRGs. About half of BRGs and of
first ranked galaxies in groups have large peculiar velocities. Groups with
elliptical BRGs as their first ranked galaxies populate superclusters more
uniformly than the groups, which have a spiral BRG as its first ranked galaxy.
The galaxy and group content of the core of the supercluster SCl~126 shows
several differences in comparison with the outskirts of this supercluster and
with the supercluster SCl~111. Our results suggest that the formation history
and evolution of individual neighbour superclusters in the SGW has been
different.Comment: Comments: 26 pages, 20 figures, accepted for publication in Ap
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