3,673 research outputs found
Does Wheat Cultivar Choice Affect Crop Quality and Soil Microbial Communities in Cropping Systems?
Wheat (Triticum aestivum L.) cultivars may have differential effects on soil microbial communities and the breadmaking quality of harvested grain. We compared six Canadian spring wheat cultivars under organic and conventional management systems for yield, breadmaking quality and soil phospholipid fatty acid analysis (PLFA) profile. Yields were lower, but protein levels were higher in the organic system. Cultivars differed for quality traits, but all cultivars had acceptable levels for processing. There were small differences in PLFA profiles for cultivars in the conventional system, but none in the organic system. More significant correlations between grain quality and PLFA measures were present in the organic system. Protein levels and breadmaking quality at least equal to conventional systems can be achieved in organic systems. Wheat cultivars differed for grain quality in both organic and conventional systems, and culivars altered the soil microbial profile in conventional systems. Microbes may play a greater role in determining crop quality in organic systems than in conventional systems
Strain bursts in plastically deforming Molybdenum micro- and nanopillars
Plastic deformation of micron and sub-micron scale specimens is characterized
by intermittent sequences of large strain bursts (dislocation avalanches) which
are separated by regions of near-elastic loading. In the present investigation
we perform a statistical characterization of strain bursts observed in
stress-controlled compressive deformation of monocrystalline Molybdenum
micropillars. We characterize the bursts in terms of the associated elongation
increments and peak deformation rates, and demonstrate that these quantities
follow power-law distributions that do not depend on specimen orientation or
stress rate. We also investigate the statistics of stress increments in between
the bursts, which are found to be Weibull distributed and exhibit a
characteristic size effect. We discuss our findings in view of observations of
deformation bursts in other materials, such as face-centered cubic and
hexagonal metals.Comment: 14 pages, 8 figures, submitted to Phil Ma
Alcohol-attributable mortality in Switzerland in 2011--age-specific causes of death and impact of heavy versus non-heavy drinking.
BACKGROUND: Alcohol use causes high burden of disease and injury globally. Switzerland has a high consumption of alcohol, almost twice the global average. Alcohol-attributable deaths and years of life lost in Switzerland were estimated by age and sex for the year 2011. Additionally, the impact of heavy drinking (40+grams/day for women and 60+g/day for men) was estimated.
METHODS: Alcohol consumption estimates were based on the Addiction Monitoring in Switzerland study and were adjusted to per capita consumption based on sales data. Mortality data were taken from the Swiss mortality register. Methodology of the Comparative Risk Assessment for alcohol was used to estimate alcohol-attributable fractions.
RESULTS: Alcohol use caused 1,600 (95% CI: 1,472 - 1,728) net deaths (1,768 deaths caused, 168 deaths prevented) among 15 to 74 year olds, corresponding to 8.7% of all deaths (men: 1,181 deaths; women: 419 deaths). Overall, 42,627 years of life (9.7%, 95% CI: 40,245 - 45,008) were lost due to alcohol. Main causes of alcohol-attributable mortality were injuries at younger ages (15-34 years), with increasing age digestive diseases (mainly liver cirrhosis) and cancers (particularly breast cancers among women). The majority (62%) of all alcohol-attributable deaths was caused by chronic heavy drinking (men: 67%; women: 48 %).
CONCLUSION: Alcohol is a major cause of premature mortality in Switzerland. Its impact, among young people mainly via injuries, among men mainly through heavy drinking, calls for a mix of preventive actions targeting chronic heavy drinking, binge drinking and mean consumption
Multiple-scattering effects on incoherent neutron scattering in glasses and viscous liquids
Incoherent neutron scattering experiments are simulated for simple dynamic
models: a glass (with a smooth distribution of harmonic vibrations) and a
viscous liquid (described by schematic mode-coupling equations). In most
situations multiple scattering has little influence upon spectral
distributions, but it completely distorts the wavenumber-dependent amplitudes.
This explains an anomaly observed in recent experiments
Nonequilibrium dynamics of a simple stochastic model
We investigate the low-temperature dynamics of a simple stochastic model,
introduced recently in the context of the physics of glasses. The slowest
characteristic time at equilibrium diverges exponentially at low temperature.
On smaller time scales, the nonequilibrium dynamics of the system exhibits an
aging regime. We present an analytical study of the scaling behaviour of the
mean energy, of its local correlation and response functions, and of the
associated fluctuation-dissipation ratio throughout the regime of low
temperature and long times. This analysis includes the aging regime, the
convergence to equilibrium, and the crossover behaviour between them.Comment: 36 pages, plain tex, 7 figures, to be published by Journal of Physics
Mechanism of sequence-specific template binding by the DNA primase of bacteriophage T7
DNA primases catalyze the synthesis of the oligoribonucleotides required for the initiation of lagging strand DNA synthesis. Biochemical studies have elucidated the mechanism for the sequence-specific synthesis of primers. However, the physical interactions of the primase with the DNA template to explain the basis of specificity have not been demonstrated. Using a combination of surface plasmon resonance and biochemical assays, we show that T7 DNA primase has only a slightly higher affinity for DNA containing the primase recognition sequence (5′-TGGTC-3′) than for DNA lacking the recognition site. However, this binding is drastically enhanced by the presence of the cognate Nucleoside triphosphates (NTPs), Adenosine triphosphate (ATP) and Cytosine triphosphate (CTP) that are incorporated into the primer, pppACCA. Formation of the dimer, pppAC, the initial step of sequence-specific primer synthesis, is not sufficient for the stable binding. Preformed primers exhibit significantly less selective binding than that observed with ATP and CTP. Alterations in subdomains of the primase result in loss of selective DNA binding. We present a model in which conformational changes induced during primer synthesis facilitate contact between the zinc-binding domain and the polymerase domain
Compact Labelings For Efficient First-Order Model-Checking
We consider graph properties that can be checked from labels, i.e., bit
sequences, of logarithmic length attached to vertices. We prove that there
exists such a labeling for checking a first-order formula with free set
variables in the graphs of every class that is \emph{nicely locally
cwd-decomposable}. This notion generalizes that of a \emph{nicely locally
tree-decomposable} class. The graphs of such classes can be covered by graphs
of bounded \emph{clique-width} with limited overlaps. We also consider such
labelings for \emph{bounded} first-order formulas on graph classes of
\emph{bounded expansion}. Some of these results are extended to counting
queries
Fibrosis-4 Index as an Independent Predictor of Mortality and Liver-Related Outcomes in NAFLD.
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, and its prevalence continues to rise. Fibrosis-4 index (FIB-4) has been shown to be a prognostic marker of liver-related outcomes in patients with NAFLD. We analyzed data from TriNetX global federated research network, combining data on 30 million patients. Patients were categorized into three diagnostic groups: NAFLD, nonalcoholic steatohepatitis (NASH), and at risk of NASH. Primary outcome was all-cause mortality, and secondary outcomes included progression to NASH, development of cirrhosis, end-stage liver disease, hepatocellular carcinoma (HCC), and liver transplantation. A total of 442,277 subjects (1.5% of the cohort) were assessed, and 81,108 were retained for analysis. Median follow-up was 34.8 months (interquartile range 12.2). FIB-4 was < 1.3 in 52.3% patients and ≥ 2.67 in 11.4% patients. In multivariate analysis, FIB-4 ≥ 2.67 was significantly and independently associated with all-cause mortality (hazard ratio [HR] 2.49, 95% confidence interval [CI] 2.20-2.82, P < 0.001) as well as with progression to NASH (HR 5.78, 95% CI 4.72-7.07, P < 0.001), cirrhosis (HR 2.04, 95% CI 1.86-2.24, P < 0.001), end-stage liver disease (HR 1.86, 95% CI 1.68-2.05, P < 0.001), HCC (HR 3.66, 95% CI 2.71-4.94, P < 0.001), and liver transplantation (HR 7.98, 95% CI 4.62-13.79, P < 0.001). Conclusion: In a real-world nationwide database, FIB-4 ≥ 2.67 was a strong predictor of both all-cause mortality and liver-related adverse outcomes independently of the baseline diagnostic group and common risk factors. Our findings indicate that FIB-4 could play a role as a risk-stratification tool for a population health approach. Significant underdiagnosis of both NAFLD/NASH and NASH cirrhosis in electronic medical records was observed
The consequence of excess configurational entropy on fragility: the case of a polymer/oligomer blend
By taking advantage of the molecular weight dependence of the glass
transition of polymers and their ability to form perfectly miscible blends, we
propose a way to modify the fragility of a system, from fragile to strong,
keeping the same glass properties, i.e. vibrational density of states,
mean-square displacement and local structure. Both slow and fast dynamics are
investigated by calorimetry and neutron scattering in an athermal
polystyrene/oligomer blend, and compared to those of a pure 17-mer polystyrene
considered to be a reference, of same Tg. Whereas the blend and the pure 17-mer
have the same heat capacity in the glass and in the liquid, their fragilities
differ strongly. This difference in fragility is related to an extra
configurational entropy created by the mixing process and acting at a scale
much larger than the interchain distance, without affecting the fast dynamics
and the structure of the glass
- …