1,355 research outputs found
Isolation, characterization and heterologous expression of a novel chitosanase from Janthinobacterium sp. strain 4239
Gut bacteria and necrotizing enterocolitis: cause or effect?
Development of necrotising enterocolitis (NEC) is considered to be dependent on the bacterial colonisation of the gut. With little concordance between published data and a recent study failing to detect a common strain in infants with NEC, more questions than answers are arising about our understanding of this complex disease
Meso- and Micro-scale Modelling in China: Wind atlas analysis for 12 meteorological stations in NE China (Dongbei)
What it takes to measure a fundamental difference between dark matter and baryons: the halo velocity anisotropy
Numerous ongoing experiments aim at detecting WIMP dark matter particles from
the galactic halo directly through WIMP-nucleon interactions. Once such a
detection is established a confirmation of the galactic origin of the signal is
needed. This requires a direction-sensitive detector. We show that such a
detector can measure the velocity anisotropy beta of the galactic halo.
Cosmological N-body simulations predict the dark matter anisotropy to be
nonzero, beta~0.2. Baryonic matter has beta=0 and therefore a detection of a
nonzero beta would be strong proof of the fundamental difference between dark
and baryonic matter. We estimate the sensitivity for various detector
configurations using Monte Carlo methods and we show that the strongest signal
is found in the relatively few high recoil energy events. Measuring beta to the
precision of ~0.03 will require detecting more than 10^4 WIMP events with
nuclear recoil energies greater than 100 keV for a WIMP mass of 100 GeV and a
32S target. This number corresponds to ~10^6 events at all energies. We discuss
variations with respect to input parameters and we show that our method is
robust to the presence of backgrounds and discuss the possible improved
sensitivity for an energy-sensitive detector.Comment: 15 pages, 8 figures, accepted by JCAP. Matches accepted versio
Tropical forcing of the Summer East Atlantic pattern
The Summer East Atlantic (SEA) mode is the second dominant mode of summer low-frequency variability in the Euro-Atlantic region. Using reanalysis data, we show that SEA-related circulation anomalies significantly influence temperatures and precipitation over Europe. We present evidence that part of the interannual SEA variability is forced by diabatic heating anomalies of opposing signs in the tropical Pacific and Caribbean that induce an extratropical Rossby wave train. This precipitation dipole is related to SST anomalies characteristic of the developing ENSO phases. Seasonal hindcast experiments forced with observed sea surface temperatures (SST) exhibit skill at capturing the interannual SEA variability corroborating the proposed mechanism and highlighting the possibility for improved prediction of boreal summer variability. Our results indicate that tropical forcing of the SEA likely played a role in the dynamics of the 2015 European heat wave
Laser-Annealing and Solid-Phase Epitaxy of Selenium Thin-Film Solar Cells
Selenium has resurged as a promising photovoltaic material in solar cell
research due to its wide direct bandgap of 1.95 eV, making it a suitable
candidate for a top cell in tandem photovoltaic devices. However, the
optoelectronic quality of selenium thin-films has been identified as a key
bottleneck for realizing high-efficiency selenium solar cells. In this study,
we present a novel approach for crystallizing selenium thin-films using
laser-annealing as an alternative to the conventionally used thermal annealing
strategy. By laser-annealing through a semitransparent substrate, a buried
layer of high-quality selenium crystallites is formed and used as a growth
template for solid-phase epitaxy. The resulting selenium thin-films feature
larger and more preferentially oriented grains with a negligible surface
roughness in comparison to thermally annealed selenium thin-films. We fabricate
photovoltaic devices using this strategy, and demonstrate a record ideality
factor of n=1.37, a record fill factor of FF=63.7%, and a power conversion
efficiency of PCE=5.0%. The presented laser-annealing strategy is universally
applicable and is a promising approach for crystallizing a wide range of
photovoltaic materials where high temperatures are needed while maintaining a
low substrate temperature
Performance of the EarlyCDTÂŽ Lung test in detection of lung cancer and pulmonary metastases in a high-risk cohort
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