663 research outputs found
(E)-2-[4-tert-Butyl-5-(2,4,5-trimethoxybenzyl)thiazol-2-yliminomethyl]phenol
In the title compound, C24H28N2O4S, the dihedral angle between the phenol ring and the thiazole ring system is 10.6 (1)°, and the trimethoxyphenyl group is approximately perpendicular to the thiazole ring, the dihedral angle being 84.7 (2)°. There is a strong intramolecular hydrogen-bonding interaction between the Schiff base and the hydroxy group
Cosmological Constraints from a Combination of Galaxy Clustering and Lensing -- III. Application to SDSS Data
We simultaneously constrain cosmology and galaxy bias using measurements of
galaxy abundances, galaxy clustering and galaxy-galaxy lensing taken from the
Sloan Digital Sky Survey. We use the conditional luminosity function (which
describes the halo occupation statistics as function of galaxy luminosity)
combined with the halo model (which describes the non-linear matter field in
terms of its halo building blocks) to describe the galaxy-dark matter
connection. We explicitly account for residual redshift space distortions in
the projected galaxy-galaxy correlation functions, and marginalize over
uncertainties in the scale dependence of the halo bias and the detailed
structure of dark matter haloes. Under the assumption of a spatially flat,
vanilla {\Lambda}CDM cosmology, we focus on constraining the matter density,
{\Omega}m, and the normalization of the matter power spectrum, {\sigma}8, and
we adopt WMAP7 priors for the spectral index, the Hubble parameter, and the
baryon density. We obtain that \Omegam = 0.278_{-0.026}^{+0.023} and {\sigma}8
= 0.763_{-0.049}^{+0.064} (95% CL). These results are robust to uncertainties
in the radial number density distribution of satellite galaxies, while allowing
for non-Poisson satellite occupation distributions results in a slightly lower
value for {\sigma}8 (0.744_{-0.047}^{+0.056}). These constraints are in
excellent agreement (at the 1{\sigma} level) with the cosmic microwave
background constraints from WMAP. This demonstrates that the use of a realistic
and accurate model for galaxy bias, down to the smallest non-linear scales
currently observed in galaxy surveys, leads to results perfectly consistent
with the vanilla {\Lambda}CDM cosmology.Comment: 21 pages, 9 figures, 5 tables, submitted to MNRA
Cosmological Constraints from a Combination of Galaxy Clustering and Lensing -- I. Theoretical Framework
We present a new method that simultaneously solves for cosmology and galaxy
bias on non-linear scales. The method uses the halo model to analytically
describe the (non-linear) matter distribution, and the conditional luminosity
function (CLF) to specify the halo occupation statistics. For a given choice of
cosmological parameters, this model can be used to predict the galaxy
luminosity function, as well as the two-point correlation functions of
galaxies, and the galaxy-galaxy lensing signal, both as function of scale and
luminosity. In this paper, the first in a series, we present the detailed,
analytical model, which we test against mock galaxy redshift surveys
constructed from high-resolution numerical -body simulations. We demonstrate
that our model, which includes scale-dependence of the halo bias and a proper
treatment of halo exclusion, reproduces the 3-dimensional galaxy-galaxy
correlation and the galaxy-matter cross-correlation (which can be projected to
predict the observables) with an accuracy better than 10 (in most cases 5)
percent. Ignoring either of these effects, as is often done, results in
systematic errors that easily exceed 40 percent on scales of \sim 1
h^{-1}\Mpc, where the data is typically most accurate. Finally, since the
projected correlation functions of galaxies are never obtained by integrating
the redshift space correlation function along the line-of-sight out to
infinity, simply because the data only cover a finite volume, they are still
affected by residual redshift space distortions (RRSDs). Ignoring these, as
done in numerous studies in the past, results in systematic errors that easily
exceed 20 perent on large scales (r_\rmp \gta 10 h^{-1}\Mpc). We show that it
is fairly straightforward to correct for these RRSDs, to an accuracy better
than percent, using a mildly modified version of the linear Kaiser
formalism
Insights into udder health and intramammary antibiotic usage on Irish dairy farms during 2003-2010
By international standards, Ireland is a relatively small dairy producer. However, the industry plays a critical role to the national economy, accounting for approximately 3% of national gross domestic product. This paper presents insights into udder health and intramammary antibiotic usage on Irish dairy farms during 2003-2010, based on data from several sources. Three data sources were used, including data on milk recording data, intramammary antibiotic sales and animal health assessment. The milk recording data included a single unadjusted herd-level somatic cell count (SCC) value for each herd at each milk recording, being the arithmetic mean of cow-level SCC of each cow at that recording, weighted by cow-level yield. These data were used to calculate the percentage of herds each month where the unadjusted herd SCC exceeded 200,000 and 400,000 cells/mL. Two logistic generalised estimating-equations (GEE) models were developed, the outcome variable being either the probability that the monthly SCC of a herd was greater than 400,000 cells/mL or less than or equal to 200,000 cells/mL. Spring herds had a lower probability of a high SCC (> 400,000 cells/mL) during February to October compared to non-Spring herds but a higher probability between November to January. The odds of a high SCC were greater in 2005, 2006, 2009 and 2010 but less in 2007 and 2008 compared to 2004. Smaller herds had higher odds of having a high SCC compared to larger herds. We present the number of intramammary tubes and the quantity of active substance (kg) sold annually in Ireland during 2003-2010. We infer an incidence of clinical mastitis of 54.0 cases per 100 cow-years at risk, assuming 4 tubes per treatment regime, one affected quarter per cow, tubes restricted to clinical cases only and 100% of treated cases considered new cases, based on data collected on sales of in-lactation intra-mammary antibiotics. With differing assumptions, this estimate varied between 25.8 and 77.0 cases per 100 cow-years at risk. Using data on sales of dry cow therapy intra-mammary antibiotics, we also infer that most Irish dairy farmers use blanket dry cow therapy. It is important that Ireland has an objective understanding of current levels of udder health, to facilitate benchmarking and improvement into the future. Udder health is a concern on a number of Irish dairy farms. High SCC results were present throughout the year, but more marked towards the start and end of each milking season. Animal Health Ireland recently commenced a major national programme, CellCheck, in collaboration with a broad range of stakeholders, to support national SCC improvement. In this paper, relevant European and national legislation is also reviewed
ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm
With the advent of wide-area submillimetre surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies have been revealed. Because of the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500 μm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimetre surveys ideal for the study of strong lens statistics. We carried out a pilot study of the lensing statistics of submillimetre-selected sources by making observations with the Atacama Large Millimeter Array (ALMA) of a sample of strongly lensed sources selected from surveys carried out with the Herschel Space Observatory. We attempted to reproduce the distribution of image separations for the lensed sources using a halo mass function taken from a numerical simulation that contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the haloes formed in the EAGLE simulation and two density distributions [Singular Isothermal Sphere (SIS) and SISSA] that have been used before in lensing studies. We found that we could reproduce the observed distribution with all three density distributions, as long as we imposed an upper mass transition of ∼1013 M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by a Navarro–Frenk–White profile. We show that we would need a sample of ∼500 lensed sources to distinguish between the density distributions, which is practical given the predicted number of lensed sources in the Herschel surveys
Satellite abundances around bright isolated galaxies
We study satellite galaxy abundances in SDSS by counting photometric galaxies
around isolated bright primaries. We present results as a function of the
luminosity, stellar mass and colour of the satellites, and of the stellar mass
and colour of the primaries. For massive primaries the luminosity and stellar
mass functions of satellites are similar in shape to those of field galaxies,
but for lower mass primaries they are significantly steeper. The steepening is
particularly marked for the stellar mass function. Satellite abundance
increases strongly with primary stellar mass, approximately in proportion to
expected dark halo mass. Massive red primaries have up to a factor of 2 more
satellites than blue ones of the same stellar mass. Satellite galaxies are
systematically redder than field galaxies of the same stellar mass. Satellites
are also systematically redder around more massive primaries. At fixed primary
mass, they are redder around red primaries. We select similarly isolated
galaxies from mock catalogues based on the simulations of Guo et al.(2011) and
analyze them in parallel with the SDSS data. The simulation reproduces all the
above trends qualitatively, except for the steepening of the satellite
luminosity and stellar mass functions. Model satellites, however, are
systematically redder than in the SDSS, particularly at low mass and around
low-mass primaries. Simulated haloes of a given mass have satellite abundances
that are independent of central galaxy colour, but red centrals tend to have
lower stellar masses, reflecting earlier quenching of their star formation by
feedback. This explains the correlation between satellite abundance and primary
colour in the simulation. The correlation between satellite colour and primary
colour arises because red centrals live in haloes which are more massive, older
and more gas-rich, so that satellite quenching is more efficient.Comment: 29 pages, 24 figure
Towards a Concordant Model of Halo Occupation Statistics
We use the conditional luminosity function (CLF) and data from the 2dFGRS to
constrain the average relation between light and mass in a LCDM cosmology with
Omega_m=0.23 and sigma_8=0.74 (hereafter WMAP3 cosmology). Reproducing the
observed luminosity dependence of the galaxy two-point correlation function
results in average mass-to-light ratios that are about 35 percent lower than in
a LCDM cosmology with Omega_m=0.3 and sigma_8=0.9 (hereafter WMAP1 cosmology).
This removes an important problem with previous halo occupation models which
had a tendency to predict cluster mass-to-light ratios that were too high. For
the WMAP3 cosmology our model yields average mass-to-light ratios, central
galaxy luminosities, halo occupation numbers, satellite fractions, and
luminosity-gap statistics, that are all in excellent agreement with those
obtained from a 2dFGRS group catalogue and from other independent studies. We
also use our CLF model to compute the probability distribution P(M|L_cen), that
a central galaxy of luminosity L_cen resides in a halo of mass M. We find this
distribution to be much broader than what is typically assumed in HOD models,
which has important implications for the interpretation of galaxy-galaxy
lensing data. Finally, reproducing the luminosity dependence of the pairwise
velocity dispersions in the 2dFGRS requires relatively low mass-to-light ratios
for clusters and a satellite fraction that decreases strongly with increasing
luminosity. This is only marginally consistent with our CLF constraints. We
argue that a cosmology with parameters between those of the WMAP1 and WMAP3
cosmologies is likely to yield results with a higher level of consistency.Comment: 23 pages, 11 figures. Submitted for publication in MNRA
Carglumic acid enhances rapid ammonia detoxification in classical organic acidurias with a favourable risk-benefit profile: A retrospective observational study
BACKGROUND: Isovaleric aciduria (IVA), propionic aciduria (PA) and methylmalonic aciduria (MMA) are inherited organic acidurias (OAs) in which impaired organic acid metabolism induces hyperammonaemia arising partly from secondary deficiency of N-acetylglutamate (NAG) synthase. Rapid reduction in plasma ammonia is required to prevent neurological complications. This retrospective, multicentre, open-label, uncontrolled, phase IIIb study evaluated the efficacy and safety of carglumic acid, a synthetic structural analogue of NAG, for treating hyperammonaemia during OA decompensation. METHODS: Eligible patients had confirmed OA and hyperammonaemia (plasma NH3 > 60 μmol/L) in ≥1 decompensation episode treated with carglumic acid (dose discretionary, mean (SD) first dose 96.3 (73.8) mg/kg). The primary outcome was change in plasma ammonia from baseline to endpoint (last available ammonia measurement at ≤18 hours after the last carglumic acid administration, or on Day 15) for each episode. Secondary outcomes included clinical response and safety. RESULTS: The efficacy population (received ≥1 dose of study drug and had post-baseline measurements) comprised 41 patients (MMA: 21, PA: 16, IVA: 4) with 48 decompensation episodes (MMA: 25, PA: 19, IVA: 4). Mean baseline plasma ammonia concentration was 468.3 (±365.3) μmol/L in neonates (29 episodes) and 171.3 (±75.7) μmol/L in non-neonates (19 episodes). At endpoint the mean plasma NH3 concentration was 60.7 (±36.5) μmol/L in neonates and 55.2 (±21.8) μmol/L in non-neonates. Median time to normalise ammonaemia was 38.4 hours in neonates vs 28.3 hours in non-neonates and was similar between OA subgroups (MMA: 37.5 hours, PA: 36.0 hours, IVA: 40.5 hours). Median time to ammonia normalisation was 1.5 and 1.6 days in patients receiving and not receiving concomitant scavenger therapy, respectively. Although patients receiving carglumic acid with scavengers had a greater reduction in plasma ammonia, the endpoint ammonia levels were similar with or without scavenger therapy. Clinical symptoms improved with therapy. Twenty-five of 57 patients in the safety population (67 episodes) experienced AEs, most of which were not drug-related. Overall, carglumic acid seems to have a good safety profile for treating hyperammonaemia during OA decompensation. CONCLUSION: Carglumic acid when used with or without ammonia scavengers, is an effective treatment for restoration of normal plasma ammonia concentrations in hyperammonaemic episodes in OA patients
Morphology of supported polymer electrolyte ultra-thin films: a numerical study
Morphology of polymer electrolytes membranes (PEM), e.g., Nafion, inside PEM
fuel cell catalyst layers has significant impact on the electrochemical
activity and transport phenomena that determine cell performance. In those
regions, Nafion can be found as an ultra-thin film, coating the catalyst and
the catalyst support surfaces. The impact of the hydrophilic/hydrophobic
character of these surfaces on the structural formation of the films has not
been sufficiently explored yet. Here, we report about Molecular Dynamics
simulation investigation of the substrate effects on the ionomer ultra-thin
film morphology at different hydration levels. We use a mean-field-like model
we introduced in previous publications for the interaction of the hydrated
Nafion ionomer with a substrate, characterized by a tunable degree of
hydrophilicity. We show that the affinity of the substrate with water plays a
crucial role in the molecular rearrangement of the ionomer film, resulting in
completely different morphologies. Detailed structural description in different
regions of the film shows evidences of strongly heterogeneous behavior. A
qualitative discussion of the implications of our observations on the PEMFC
catalyst layer performance is finally proposed
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