1,229 research outputs found
A first unbiased global NLO determination of parton distributions and their uncertainties
We present a determination of the parton distributions of the nucleon from a
global set of hard scattering data using the NNPDF methodology: NNPDF2.0.
Experimental data include deep-inelastic scattering with the combined HERA-I
dataset, fixed target Drell-Yan production, collider weak boson production and
inclusive jet production. Next-to-leading order QCD is used throughout without
resorting to K-factors. We present and utilize an improved fast algorithm for
the solution of evolution equations and the computation of general hadronic
processes. We introduce improved techniques for the training of the neural
networks which are used as parton parametrization, and we use a novel approach
for the proper treatment of normalization uncertainties. We assess
quantitatively the impact of individual datasets on PDFs. We find very good
consistency of all datasets with each other and with NLO QCD, with no evidence
of tension between datasets. Some PDF combinations relevant for LHC observables
turn out to be determined rather more accurately than in any other parton fit.Comment: 86 pages, 41 figures. PDF sets available from
http://sophia.ecm.ub.es/nnpdf/nnpdf_pdfsets.htm and from LHAPDF. Final
version to be published in Nucl. Phys. B. Various typos corrected and small
clarifications added, fig. 4 added, extended discussion of data consistency
especially in sect 5.1 and 5.
Granular packings of elongated faceted particles deposited under gravity
We report experimental and theoretical results of the effect that
particle shape has on the packing properties of granular materials. We
have systematically measured the particle angular distribution, the cluster size
distribution and the stress profiles of ensembles of faceted elongated particles
deposited in a bidimensional box. Stress transmission through this granular
system has been numerically simulated using a two-dimensional model of irregular
particles. For grains of maximum symmetry (squares), the stress propagation
localizes and forms chain-like forces analogous to those observed for granular
materials composed of spheres. For thick layers of grains, a pressure saturation
is observed for deposit depths beyond a characteristic length. This scenario
correlates with packing morphology and can be understood in terms of stochastic
models of aggregation and random multiplicative processes. As grains elongate
and lose their symmetry, stress propagation is strongly affected. Lateral force
transmission becomes less favored than vertical transfer, and hence, an increase
in the pressure develops with depth, hindering force saturation
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Effects of ultrasound versus pasteurization on wheyâoat beverage processing: quality and antioxidative properties
The consumption of functional beverages is rapidly increasing. The improvement in the
functional properties of whey after the application of ultrasound is due to the release of bioactive
peptides that have antioxidant properties, among others. Bioactive peptides with antioxidant activity
have also been found in oats, stimulating the study of whey beverages formulated with oats to
obtain functional products. The aim of this study was to determine the influence of ultrasound
(24 kHz) at 20 °C for 15 min at 23 W and 154 W on the quality and functional properties of wheyâoat
(50:50 v/v) beverages and compare it with pasteurization at 65 °C for 30 min (LTLT). Non-significant
effect (p > 0.05) of ultrasound intensity (23 W and 154 W) was observed on the physicochemical
characteristics and the proximal composition of the wheyâoat beverages. The sonicated beverages
showed a greater tendency to green and yellow color (p < 0.05), higher fat content (p < 0.05), and
less ash and carbohydrates (p < 0.05) than the pasteurized beverage. The antioxidant activity of the
mM Trolox equivalent/mL of the sonicated beverages was higher (p < 0.05) (4.24 and 4.27 for 23W
and 54 W, respectively) compared to that of the pasteurized beverage (4.12). It is concluded that
ultrasound is superior to pasteurization in improving the antioxidant activity of wheyâoat beverages
without having a detrimental impact on the proximal composition and physicochemical quality.
Future studies should evaluate more functional parameters and determine the shelf life of sonicated
wheyâoat beverages
Association between the plasma/whole blood lead ratio and history of spontaneous abortion: a nested cross-sectional study
<p>Abstract</p> <p>Background</p> <p>Blood lead has been associated with an elevated risk of miscarriage. The plasmatic fraction of lead represents the toxicologically active fraction of lead. Women with a tendency to have a higher plasma/whole blood Pb ratio could tend towards an elevated risk of miscarriage due to a higher plasma Pb for a given whole blood Pb and would consequently have a history of spontaneous abortion.</p> <p>Methods</p> <p>We studied 207 pregnant Mexico City residents during the 1<sup>st </sup>trimester of pregnancy, originally recruited for two cohorts between 1997 and 2004. Criteria for inclusion in this study were having had at least one previous pregnancy, and having valid plasma and blood Pb measurements. Pb was measured in whole blood and plasma by inductively coupled plasma mass spectrometry using ultra-clean techniques. History of miscarriage in previous pregnancies was obtained by interview. The incidence rate of spontaneous abortion was defined as the proportion of previous pregnancies that resulted in miscarriage. Data were analyzed by means of Poisson regression models featuring the incidence rate of spontaneous abortion as the outcome and continuous or categorized plasma/blood Pb ratios as predictor variables. All models were adjusted for age and schooling. Additionally, logistic regression models featuring inclusion in the study sample as the outcome were fitted to assess potential selection bias.</p> <p>Results</p> <p>The mean number of miscarriages was 0.42 (range 0 to 4); mean Pb concentrations were 62.4 and 0.14 ÎŒg/L in whole blood and plasma respectively. Mean plasma/blood Pb ratio was 0.22%. We estimated that a 0.1% increment in the plasma/blood Pb ratio lead was associated to a 12% greater incidence of spontaneous abortion (p = 0.02). Women in the upper tertile of the plasma/blood Pb ratio had twice the incidence rate of those in the lower tertile (p = 0.02). Conditional on recruitment cohort, inclusion in the study sample was unrelated to observable characteristics such as number of abortions, number of pregnancies, blood Pb levels, age schooling, weight and height.</p> <p>Conclusion</p> <p>Women with a large plasma/whole blood Pb ratio may be at higher risk of miscarriage, which could be due to a greater availability of placental barrier-crossing Pb.</p
Granular Solid Hydrodynamics
Granular elasticity, an elasticity theory useful for calculating static
stress distribution in granular media, is generalized to the dynamic case by
including the plastic contribution of the strain. A complete hydrodynamic
theory is derived based on the hypothesis that granular medium turns
transiently elastic when deformed. This theory includes both the true and the
granular temperatures, and employs a free energy expression that encapsulates a
full jamming phase diagram, in the space spanned by pressure, shear stress,
density and granular temperature. For the special case of stationary granular
temperatures, the derived hydrodynamic theory reduces to {\em hypoplasticity},
a state-of-the-art engineering model.Comment: 42 pages 3 fi
FGFR4 regulates tumor subtype differentiation in luminal breast cancer and metastatic disease
Mechanisms driving tumor progression from less aggressive subtypes to more aggressive states represent key targets for therapy. We identified a subset of luminal A primary breast tumors that give rise to HER2-enriched (HER2E) subtype metastases, but remain clinically HER2 negative (cHER2-). By testing the unique genetic and transcriptomic features of these cases, we developed the hypothesis that FGFR4 likely participates in this subtype switching. To evaluate this, we developed 2 FGFR4 genomic signatures using a patient-derived xenograft (PDX) model treated with an FGFR4 inhibitor, which inhibited PDX growth in vivo. Bulk tumor gene expression analysis and single-cell RNA sequencing demonstrated that the inhibition of FGFR4 signaling caused molecular switching. In the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) breast cancer cohort, FGFR4-induced and FGFR4-repressed signatures each predicted overall survival. Additionally, the FGFR4-induced signature was an independent prognostic factor beyond subtype and stage. Supervised analysis of 77 primary tumors with paired metastases revealed that the FGFR4-induced signature was significantly higher in luminal/ER+ tumor metastases compared with their primaries. Finally, multivariate analysis demonstrated that the FGFR4- induced signature also predicted site-specific metastasis for lung, liver, and brain, but not for bone or lymph nodes. These data identify a link between FGFR4-regulated genes and metastasis, suggesting treatment options for FGFR4-positive patients, whose high expression is not caused by mutation or amplification
Highlights from the Pierre Auger Observatory
The Pierre Auger Observatory is the world's largest cosmic ray observatory.
Our current exposure reaches nearly 40,000 km str and provides us with an
unprecedented quality data set. The performance and stability of the detectors
and their enhancements are described. Data analyses have led to a number of
major breakthroughs. Among these we discuss the energy spectrum and the
searches for large-scale anisotropies. We present analyses of our X
data and show how it can be interpreted in terms of mass composition. We also
describe some new analyses that extract mass sensitive parameters from the 100%
duty cycle SD data. A coherent interpretation of all these recent results opens
new directions. The consequences regarding the cosmic ray composition and the
properties of UHECR sources are briefly discussed.Comment: 9 pages, 12 figures, talk given at the 33rd International Cosmic Ray
Conference, Rio de Janeiro 201
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