4,306 research outputs found
Proposal of Direct Search for Strongly Bound States of ppbar, npbar Systems with High Intensity and Collective pbar beam
In this letter, we discuss the possibility to look for the direct evidence of
the existence of the ppbar and npbar bound states. Measurement of the single
\gamma ray from the ppbar and npbar systems at rest can directly confirm
whether the X(1860) and X(1835) are the resonances which are strongly coupled
to ppbar. In addition to the neutral candidate, a charged resonance is
also proposed to be searched for in npbar channel. We find that the data from
the Crystal Barrel experiment at LEAR/CERN can be used to confirm the X(1835)
observed by BES Collaboration. The possibility of measuring the
spectrum below 100 MeV at the new experiment with cold high intensity \pbar
beam at GSI is discussed. These new techniques can be used to probe the
structure of the X(1860) and X(1835) in the future.Comment: Accepted by Mod. Phys. Lett.
Modeling nitrogen loading in a small watershed in southwest China using a DNDC model with hydrological enhancements
The degradation of water quality has been observed worldwide, and inputs of nitrogen (N), along with other nutrients, play a key role in the process of contamination. The quantification of N loading from non-point sources at a watershed scale has long been a challenge. Process-based models have been developed to address this problem. Because N loading from non-point sources result from interactions between biogeochemical and hydrological processes, a model framework must include both types of processes if it is to be useful. This paper reports the results of a study in which we integrated two fundamental hydrologic features, the SCS (Soil Conservation Service) curve function and the MUSLE (Modified Universal Soil Loss), into a biogeochemical model, the DNDC. The SCS curve equation and the MUSLE are widely used in hydrological models for calculating surface runoff and soil erosion. Equipped with the new added hydrologic features, DNDC was substantially enhanced with the new capacity of simulating both vertical and horizontal movements of water and N at a watershed scale. A long-term experimental watershed in Southwest China was selected to test the new version of the DNDC. The target watershed\u27s 35.1 ha of territory encompass 19.3 ha of croplands, 11.0 ha of forest lands, 1.1 ha of grassplots, and 3.7 ha of residential areas. An input database containing topographic data, meteorological conditions, soil properties, vegetation information, and management applications was established and linked to the enhanced DNDC. Driven by the input database, the DNDC simulated the surface runoff flow, the subsurface leaching flow, the soil erosion, and the N loadings from the target watershed. The modeled water flow, sediment yield, and N loading from the entire watershed were compared with observations from the watershed and yielded encouraging results. The sources of N loading were identified by using the results of the model. In 2008, the modeled runoff-induced loss of total N from the watershed was 904 kg N yr−1, of which approximately 67 % came from the croplands. The enhanced DNDC model also estimated the watershed-scale N losses (1391 kg N yr−1) from the emissions of the N-containing gases (ammonia, nitrous oxide, nitric oxide, and dinitrogen). Ammonia volatilization (1299 kg N yr−1) dominated the gaseous N losses. The study indicated that process-based biogeochemical models such as the DNDC could contribute more effectively to watershed N loading studies if the hydrological components of the models were appropriately enhanced
A general framework for analyzing tumor subclonality using SNP array and DNA sequencing data
Abstract
Intra-tumor heterogeneity reflects cancer genome evolution and provides key information for diagnosis and treatment. When bulk tumor tissues are profiled for somatic copy number alterations (sCNA) and point mutations, it may be difficult to estimate their cellular fractions when a mutation falls within a sCNA. We present the Clonal Heterogeneity Analysis Tool, which estimates cellular fractions for both sCNAs and mutations, and uses their distributions to inform macroscopic clonal architecture. In a set of approximately 700 breast tumors, more than half appear to contain multiple recognizable aneuploid tumor clones, and many show subtype-specific differences in clonality for known cancer genes.http://deepblue.lib.umich.edu/bitstream/2027.42/109534/1/13059_2014_Article_473.pd
Quantum kernels with squeezed-state encoding for machine learning
Kernel methods are powerful for machine learning, as they can represent data
in feature spaces that similarities between samples may be faithfully captured.
Recently, it is realized that machine learning enhanced by quantum computing is
closely related to kernel methods, where the exponentially large Hilbert space
turns to be a feature space more expressive than classical ones. In this paper,
we generalize quantum kernel methods by encoding data into continuous-variable
quantum states, which can benefit from the infinite-dimensional Hilbert space
of continuous variables. Specially, we propose squeezed-state encoding, in
which data is encoded as either in the amplitude or the phase. The kernels can
be calculated on a quantum computer and then are combined with classical
machine learning, e.g. support vector machine, for training and predicting
tasks. Their comparisons with other classical kernels are also addressed.
Lastly, we discuss physical implementations of squeezed-state encoding for
machine learning in quantum platforms such as trapped ions.Comment: 5 pages, 4 figure
STREAMER WAVES DRIVEN BY CORONAL MASS EJECTIONS
Between July 5th and July 7th 2004, two intriguing fast coronal mass
ejection(CME)-streamer interaction events were recorded by the Large Angle and
Spectrometric Coronagraph (LASCO). At the beginning of the events, the streamer
was pushed aside from their equilibrium position upon the impact of the rapidly
outgoing and expanding ejecta; then, the streamer structure, mainly the bright
streamer belt, exhibited elegant large scale sinusoidal wavelike motions. The
motions were apparently driven by the restoring magnetic forces resulting from
the CME impingement, suggestive of magnetohydrodynamic kink mode propagating
outwards along the plasma sheet of the streamer. The mode is supported
collectively by the streamer-plasma sheet structure and is therefore named
"streamer wave" in the present study. With the white light coronagraph data, we
show that the streamer wave has a period of about 1 hour, a wavelength varying
from 2 to 4 solar radii, an amplitude of about a few tens of solar radii, and a
propagating phase speed in the range 300 to 500 km s. We also find that
there is a tendancy for the phase speed to decline with increasing heliocentric
distance. These observations provide good examples of large scale wave
phenomena carried by coronal structures, and have significance in developing
seismological techniques for diagnosing plasma and magnetic parameters in the
outer corona.Comment: 8 pages, 7 figures, accepted for publication in Ap
The dispersive contribution of decays and X(1576)
We study whether the broad enhancement X(1576) arises from the final state
interaction (FSI) of decays. We
consider both the absorptive and dispersive contribution of the above
amplitudes since the intermediate states are very close to .
The same mechanism leads to a similar enhancement around 1580 MeV in the
spectrum in the channel, which
can be used to test whether X(1576) can be ascribed to the FSI effect of
.Comment: 4 pages, 4 figure
How does the Combined Risk Affect the Performance of Unsupervised Domain Adaptation Approaches ?
Effects of supplementing lactic acid bacteria on fecal microbiota, total cholesterol, triglycerides and bile acids in rats.
Background: Probiotics (LAB) are normal components of the intestinal micro-flora in both humans and animals and its ingestion in decreasing the risk of atherosclerosis. In addition, the potential health effects of LAB were investigated by monitoring changes in intestinal micro-flora and lipid metabolism in a rat model.Materials and Methods: Rats were randomly assigned into four treatments and fecal samples were obtained on days 1, 3, 5, 9 and 14,to evaluate fecal micro biota, total cholesterol (TC), triglycerides (TG) and bile acids in rats (TBA).Results: The results indicated that Lactobacillus plantarum strain L.p X3-2B increased fecal lactic acid bacteria(LAB) and Bifidobacterium while resisting the growth of harmful bacteria. Viable counts of LAB and Bifidobacterium reached 8 log cfu/mL after feeding for 14 days. Fecal pH in the control group was high in comparison with the treatments at all times. Treatment increased the excretion of triglycerides (TG), total cholesterol (TC) and total bile acid (TBA). The results indicate that LAB and Bifidobacterium induce a positive correlation with fecal TC, TG and TBA and a negative correlation with fecal Enterobacteriaceae, Enterococcus and Escherichia coli.Conclusion: Lactic acid bacteria screened from Inner Mongolia native meat sausages in China had cholesterol-lowering effect.Keywords: Lactic acid bacteria, fecal micro biota, TC, TG, TB
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