6,486 research outputs found
Small-Angle Excess Scattering: Glassy Freezing or Local Orientational Ordering?
We present Monte Carlo simulations of a dense polymer melt which shows
glass-transition-like slowing-down upon cooling, as well as a build up of
nematic order. At small wave vectors q this model system shows excess
scattering similar to that recently reported for light-scattering experiments
on some polymeric and molecular glass-forming liquids. For our model system we
can provide clear evidence that this excess scattering is due to the onset of
short-range nematic order and not directly related to the glass transition.Comment: 3 Pages of Latex + 4 Figure
What Makes Agricultural Intensification Profitable for Mozambican Smallholders? An Appraisal of the Inputs Subsector and the 1996/97 DNER/SG2000 Program
This report summarizes an appraisal of input utilization and marketing in Mozambique, focusing on the following research questions: (1) What are current smallholder yields for major commodities, and what is the potential for increasing yields through the use of improved technologies? (2) To what extent are improved technologies already being used by smallholders, and is the use of improved technologies profitable? (3) How are improved seeds, fertilizer and pesticides currently produced and distributed? and (4) What are the key constraints and opportunities for increasing the use of improved technologies by smallholders?food security, food policy, improved technologies, Farm Management, Downloads July 2008-July 2009: 9, O31,
Is Agricultural Intensification Profitable For Mozambican Smallholders? An Appraisal of the Inputs Subsector and the 1996/97 DNER/Sg2000 Program
Farm Management, Downloads July 2008-June 2009: 5,
What Makes Agricultural Intensification Profitable for Mozambican Smallholders? An Appraisal of the Inputs Subsector and the 1996/97 DNER/SG2000 Program, Volume II: Main Report
Ministry of Agriculture and Rural Development, Directorate of Economics, Republic of Mozambiquefood security, food policy, Mozambique, agriculture, Farm Management, Q18,
Analysis of the P branch of the [nu]6 fundamental of carbon suboxide
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23682/1/0000651.pd
Hypogravity reduces trunk admittance and lumbar muscle activation in response to external perturbations
Reduced paraspinal muscle size and flattening of spinal curvatures have been documented after spaceflight. Assessment of trunk adaptations to hypogravity can contribute to develop specific countermeasures. In this study, parabolic flights were used to investigate spinal curvature and muscle responses to hypogravity. Data from five trials at 0.25g, 0.50g and 0.75g were recorded from six participants, positioned in a kneeling-seated position. During the first two trials, participants maintained a normal, upright posture. In the last three trials, small-amplitude perturbations were delivered in the anterior direction at the T10 level. Spinal curvature was estimated using motion capture cameras. Trunk displacement and contact force between the actuator and participant were recorded. Muscle activity responses were collected using intramuscular electromyography (iEMG) of the deep and superficial lumbar multifidus, iliocostalis lumborum, longissimus thoracis, quadratus lumborum, transversus abdominis, obliquus internus and obliquus externus muscles. The root mean square iEMG and the average spinal angles were calculated. Trunk admittance and muscle responses to perturbations were calculated as closed-loop frequency response functions. Compared with 0.75g, 0.25g resulted in: lower activation of the longissimus thoracis (P=0.002); lower responses of the superficial multifidus at low frequencies (P=0.043); lower responses of the superficial multifidus (P=0.029) and iliocostalis lumborum (P=0.043); lower trunk admittance (P=0.037) at intermediate frequencies; and stronger responses of the transversus abdominis at higher frequencies (p=0.032). These findings indicate that exposure to hypogravity reduces trunk admittance, partially compensated by weaker stabilizing contributions of the paraspinal muscles and coinciding with an apparent increase of the deep abdominal muscle activity
Quantification of Mineral Oil Aromatic Hydrocarbons (MOAH) in Anhydrous Cosmetics Using 1 H NMR
In cosmetic products, hydrocarbons from mineral oil origin are used as ingredients in a wide variety of consistency, from liquid oil to solid wax. Refined mineral oil hydrocarbons consist of MOSH (mineral oil saturated hydrocarbons) and a low proportion of MOAH (mineral oil aromatic hydrocarbons). MOSH and MOAH comprise a variety of chemically similar single substances with straight or branched chains. In the context of precautionary consumer protection, it is crucial to determine hydrocarbons from mineral oil origin of inferior quality quickly and efficiently. This publication presents a rapid method for quantifying MOAH by proton nuclear magnetic resonance spectroscopy (¹H qNMR) in anhydrous cosmetics such as lipstick, lip gloss, and lip balm. A sample clean-up using solid-phase extraction (SPE) was developed for the complete removal of interfering aromatic substances to improve the robustness of the method for analysing compounded cosmetics. In preliminary trials using silica gel thin-layer chromatography, the retention behaviour of 21 common aromatic compounds was tested in eluents with different solvent strength including EtOAc, MeOH, cyclohexane, and dichloromethane. Based on these results, the SPE sample cleanup with silica gel and cyclohexane as an eluent was suggested as best suitable for the purpose. The SPE cleanup was successfully achieved for all tested potentially interfering aromatic cosmetic ingredients except for butylated hydroxytoluene. The recovery for lipophilic cosmetics is more than 80% based on naphthalene as calculation equivalent. Furthermore, a specific sample preparation for the examination of lipsticks was implemented. The SPE cleanup was validated, and the robustness of the method was tested on 57 samples from the retail trade. The ¹H qNMR method is a good complement to the LC-GC-FID method, which is predominantly used for the determination of MOSH and MOAH. Chromatographic problems such as migration of MOSH into the MOAH fraction during LC-GC-FID can be avoided
Data series subtraction with unknown and unmodeled background noise
LISA Pathfinder (LPF), ESA's precursor mission to a gravitational wave
observatory, will measure the degree to which two test-masses can be put into
free-fall, aiming to demonstrate a residual relative acceleration with a power
spectral density (PSD) below 30 fm/s/Hz around 1 mHz. In LPF data
analysis, the measured relative acceleration data series must be fit to other
various measured time series data. This fitting is required in different
experiments, from system identification of the test mass and satellite dynamics
to the subtraction of noise contributions from measured known disturbances. In
all cases, the background noise, described by the PSD of the fit residuals, is
expected to be coloured, requiring that we perform such fits in the frequency
domain. This PSD is unknown {\it a priori}, and a high accuracy estimate of
this residual acceleration noise is an essential output of our analysis. In
this paper we present a fitting method based on Bayesian parameter estimation
with an unknown frequency-dependent background noise. The method uses noise
marginalisation in connection with averaged Welch's periodograms to achieve
unbiased parameter estimation, together with a consistent, non-parametric
estimate of the residual PSD. Additionally, we find that the method is
equivalent to some implementations of iteratively re-weighted least-squares
fitting. We have tested the method both on simulated data of known PSD, and to
analyze differential acceleration from several experiments with the LISA
Pathfinder end-to-end mission simulator.Comment: To appear Phys. Rev. D90 August 201
The B-cell inhibitory receptor CD22 is a major factor in host resistance to Streptococcus pneumoniae infection
Streptococcus pneumoniae is a major human pathogen, causing pneumonia and sepsis. Genetic components strongly influence host responses to pneumococcal infections, but the responsible loci are unknown. We have previously identified a locus on mouse chromosome 7 from a susceptible mouse strain, CBA/Ca, to be crucial for pneumococcal infection. Here we identify a responsible gene, Cd22, which carries a point mutation in the CBA/Ca strain, leading to loss of CD22 on B cells. CBA/Ca mice and gene-targeted CD22-deficient mice on a C57BL/6 background are both similarly susceptible to pneumococcal infection, as shown by bacterial replication in the lungs, high bacteremia and early death. After bacterial infections, CD22-deficient mice had strongly reduced B cell populations in the lung, including GM-CSF producing, IgM secreting innate response activator B cells, which are crucial for protection. This study provides striking evidence that CD22 is crucial for protection during invasive pneumococcal disease.info:eu-repo/semantics/publishedVersio
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