283 research outputs found
Caractérisation -par spectrométrie RMN du 31P- de constituants phosphatés extraits de sols de rizières malgaches
Les composés phosphatés de six sols de rizières, riches en matière organique, originaires de Madagascar ont été extraits par une solution sodique. Ces composés ont été déterminés soit par une analyse chimique globale, soit par une spectrométrie RMN du 31P du phosphore qu'ils contenaien
Development of a high-resolution NGS-based HLA-typing and analysis pipeline
The human leukocyte antigen (HLA) complex contains the most polymorphic genes in the human genome. The classical HLA class I and II genes define the specificity of adaptive immune responses. Genetic variation at the HLA genes is associated with susceptibility to autoimmune and infectious diseases and plays a major role in transplantation medicine and immunology. Currently, the HLA genes are characterized using Sanger- or next-generation sequencing (NGS) of a limited amplicon repertoire or labeled oligonucleotides for allele-specific sequences. High-quality NGS-based methods are in proprietary use and not publicly available. Here, we introduce the first highly automated open-kit/open-source HLA-typing method for NGS. The method employs in-solution targeted capturing of the classical class I (HLA-A, HLA-B, HLA-C) and class II HLA genes (HLA-DRB1, HLA-DQA1, HLA-DQB1, HLA-DPA1, HLA-DPB1). The calling algorithm allows for highly confident allele-calling to three-field resolution (cDNA nucleotide variants). The method was validated on 357 commercially available DNA samples with known HLA alleles obtained by classical typing. Our results showed on average an accurate allele call rate of 0.99 in a fully automated manner, identifying also errors in the reference data. Finally, our method provides the flexibility to add further enrichment target regions
Critical scaling of the a.c. conductivity for a superconductor above Tc
We consider the effects of critical superconducting fluctuations on the
scaling of the linear a.c. conductivity, \sigma(\omega), of a bulk
superconductor slightly above Tc in zero applied magnetic field. The dynamic
renormalization- group method is applied to the relaxational time-dependent
Ginzburg-Landau model of superconductivity, with \sigma(\omega) calculated via
the Kubo formula to O(\epsilon^{2}) in the \epsilon = 4 - d expansion. The
critical dynamics are governed by the relaxational XY-model
renormalization-group fixed point. The scaling hypothesis \sigma(\omega) \sim
\xi^{2-d+z} S(\omega \xi^{z}) proposed by Fisher, Fisher and Huse is explicitly
verified, with the dynamic exponent z \approx 2.015, the value expected for the
d=3 relaxational XY-model. The universal scaling function S(y) is computed and
shown to deviate only slightly from its Gaussian form, calculated earlier. The
present theory is compared with experimental measurements of the a.c.
conductivity of YBCO near Tc, and the implications of this theory for such
experiments is discussed.Comment: 16 pages, submitted to Phys. Rev.
Using the past to constrain the future: how the palaeorecord can improve estimates of global warming
Climate sensitivity is defined as the change in global mean equilibrium
temperature after a doubling of atmospheric CO2 concentration and provides a
simple measure of global warming. An early estimate of climate sensitivity,
1.5-4.5{\deg}C, has changed little subsequently, including the latest
assessment by the Intergovernmental Panel on Climate Change.
The persistence of such large uncertainties in this simple measure casts
doubt on our understanding of the mechanisms of climate change and our ability
to predict the response of the climate system to future perturbations. This has
motivated continued attempts to constrain the range with climate data, alone or
in conjunction with models. The majority of studies use data from the
instrumental period (post-1850) but recent work has made use of information
about the large climate changes experienced in the geological past.
In this review, we first outline approaches that estimate climate sensitivity
using instrumental climate observations and then summarise attempts to use the
record of climate change on geological timescales. We examine the limitations
of these studies and suggest ways in which the power of the palaeoclimate
record could be better used to reduce uncertainties in our predictions of
climate sensitivity.Comment: The final, definitive version of this paper has been published in
Progress in Physical Geography, 31(5), 2007 by SAGE Publications Ltd, All
rights reserved. \c{opyright} 2007 Edwards, Crucifix and Harriso
Objectively measured physical activity in european adults: cross-sectional findings from the Food4Me study
Introduction
Physical inactivity has been estimated to be responsible for more than 5.3 million deaths worldwide
[1]. Moreover, among European men and women, approximately 7.3% of all deaths in
2008 might be attributable to inactivity compared with 3.7% to obesity [2] and there is strong
evidence to suggest that even small increases in physical activity (PA) would lower the risk for
many non-communicable diseases [1–3]. Yet, levels of PA across populations remain low [4].
To tackle this public health issue, the US Centers for Disease Control and Prevention and the
American College of Sports Medicine produced standardized PA guidelines 20 years ago [5].
Since then, the World Health Organization (WHO), the European Union, and most countries
around the world, have included PA guidelines in their health policies. Guidelines for Americans
and Europeans have been updated to include recommendations for adolescents and for
older adults [6–9]. For adults aged 18–64 years old, the WHO recommends a minimum of 150
min of moderate intensity PA per week, 75 min of vigorous intensity PA or an equivalent
amount of moderate and vigorous PA (MVPA) [9].
In 2008, 34.8% of adults 15 years or older were insufficiently active in Europe [4]. Regular
surveillance is needed to update these prevalence estimates and to evaluate the effectiveness of
PA policies and promotion programs in European countries. In this context, the objective
assessment of PA is a key issue. Prevalence of physical inactivity has been mainly derived from
self-reported measures such as the Baecke questionnaire [10] or the International Physical
Activity Questionnaire (IPAQ) [11]. These questionnaires have been, and still are, widely used
due to their simple administration and low cost [12]. However, PA is frequently misreported,
which leads to considerable measurement error [13–15]. Accelerometers offer a potential solution
because they measure PA objectively. Given that they are small and easy to wear, store
data up to several weeks and are acceptable in terms of reliability, these devices are now used
increasingly in large studies to assess PA in children, adolescents and adults [16]. Although
some European countries have reported adherence to PA guidelines using accelerometers in
large cohorts [17–19], comparisons between European countries measured according to the
same standardized protocols and concurrently are lacking.
Between 2012 and 2014, PA was assessed objectively by accelerometry in the participants of
the Food4Me Proof-of-Principle (PoP) study. The Food4Me Study was a web-based randomized
controlled trial on personalized nutrition, across seven European countries: Germany,
Greece, Ireland, The Netherlands, Poland, Spain and the United Kingdom. The aim of the current
paper is to describe and compare PA in adults from these countries, and evaluate adherence
to PA guidelines, using baseline data from the Food4Me PoP study
EuFeAs under high pressure: an antiferromagnetic bulk superconductor
We report the ac magnetic susceptibility and resistivity
measurements of EuFeAs under high pressure . By observing nearly
100% superconducting shielding and zero resistivity at = 28 kbar, we
establish that -induced superconductivity occurs at ~30 K in
EuFeAs. shows an anomalous nearly linear temperature dependence
from room temperature down to at the same . indicates that
an antiferromagnetic order of Eu moments with ~20 K persists
in the superconducting phase. The temperature dependence of the upper critical
field is also determined.Comment: To appear in J. Phys. Soc. Jpn., Vol. 78 No.
A search for the decay
We search for the rare flavor-changing neutral-current decay in a data sample of 82 fb collected with the {\sl BABAR}
detector at the PEP-II B-factory. Signal events are selected by examining the
properties of the system recoiling against either a reconstructed hadronic or
semileptonic charged-B decay. Using these two independent samples we obtain a
combined limit of
at the 90% confidence level. In addition, by selecting for pions rather than
kaons, we obtain a limit of using only the hadronic B reconstruction method.Comment: 7 pages, 8 postscript figures, submitted to Phys. Rev. Let
High-reflectivity broadband distributed Bragg reflector lattice matched to ZnTe
We report on the realization of a high quality distributed Bragg reflector
with both high and low refractive index layers lattice matched to ZnTe. Our
structure is grown by molecular beam epitaxy and is based on binary compounds
only. The high refractive index layer is made of ZnTe, while the low index
material is made of a short period triple superlattice containing MgSe, MgTe,
and ZnTe. The high refractive index step of Delta_n=0.5 in the structure
results in a broad stopband and the reflectivity coefficient exceeding 99% for
only 15 Bragg pairs.Comment: 4 pages, 3 figure
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