833 research outputs found
Test of OPE and OGE through mixing angles of negative parity N* resonances in electromagnetic transitions
In this report, by using the mixing angles of one-gluon-exchange model(OGE)
and one-pion-exchange model(OPE), and by using the electromagnetic Hamiltonian
of Close and Li, we calculate the amplitudes of L=1 N* resonances for
photoproduction and electroproduction. The results are compared to experimental
data. It's found that the data support OGE, not OPE.Comment: 5 pages, Latex, 1 figure, accepted by Phys.Rev.
Analysis of Rainfall Infiltration Law in Unsaturated Soil Slope
In the study of unsaturated soil slope stability under rainfall infiltration, it is worth continuing to explore how much rainfall infiltrates into the slope in a rain process, and the amount of rainfall infiltrating into slope is the important factor influencing the stability. Therefore, rainfall infiltration capacity is an important issue of unsaturated seepage analysis for slope. On the basis of previous studies, rainfall infiltration law of unsaturated soil slope is analyzed. Considering the characteristics of slope and rainfall, the key factors affecting rainfall infiltration of slope, including hydraulic properties, water storage capacity ( − ), soil types, rainfall intensities, and antecedent and subsequent infiltration rates on unsaturated soil slope, are discussed by using theory analysis and numerical simulation technology. Based on critical factors changing, this paper presents three calculation models of rainfall infiltrability for unsaturated slope, including (1) infiltration model considering rainfall intensity; (2) effective rainfall model considering antecedent rainfall; (3) infiltration model considering comprehensive factors. Based on the technology of system response, the relationship of rainfall and infiltration is described, and the prototype of regression model of rainfall infiltration is given, in order to determine the amount of rain penetration during a rain process
The study of Seyfert 2 galaxies with and without infrared broad lines
From the literature, we construct from literature a sample of 25 Seyfert 2
galaxies (S2s) with a broad line region detected in near infrared spectroscopy
and 29 with NIR BLR which was detected. We find no significant difference
between the nuclei luminosity (extinction-corrected [OIII]~5007) and infrared
color between the two populations, suggesting that the
non-detections of NIR BLR could not be due to low AGN luminosity or
contamination from the host galaxy. As expected, we find significantly lower
X-ray obscurations in Seyfert 2s with NIR BLR detection, supporting the
unification scheme. However, such a scheme was challenged by the detection of
NIR BLR in heavily X-ray obscured sources, especially in six of them with
Compton-thick X-ray obscuration. The discrepancy could be solved by the clumpy
torus model and we propose a toy model demonstrating that IR-thin X-ray-thick
S2s could be viewed at intermediate inclinations, and compared with those
IR-thick X-ray-thick S2s. We note that two of the IR-thin X-ray-thick S2s (NGC
1386 and NGC 7674) experienced X-ray transitions, i.e. from Compton-thin to
Compton-thick appearance or vice versa based on previous X-ray observations,
suggesting that X-ray transitions could be common in this special class of
objects
Long-range Effects on the Pyroelectric Coefficient and Dielectric Susceptibility of a Ferroelectric Bilayer
Long-range effects on the pyroelectric coefficient and susceptibility of a
ferroelectric bilayer with a ferroelectric interfacial coupling are
investigated by use of the transverse Ising model within the framework of
mean-field theory. The effects of the interfacial coupling and the transverse
field on the pyroelectric coefficient and susceptibility of the bilayer are
investigated by taking into account the long-range interaction. It is found
that the pyroelectric coefficient and susceptibility increase with the decrease
of the magnitude of the long-range interaction and the interfacial coupling
when the temperature is lower than the phase transition temperature. We also
find that the strong long-range interaction, the large transverse field and
weak interfacial coupling can lead to the disappearance of some of the peaks of
the pyroelectric coefficient and susceptibility of the ferroelectric bilayer.
The phase transition temperature increases with the increase of the strength of
the long-range interaction, which is similar to the results obtained in
ferroelectric multi-layers or superlattice.Comment: 23 pages, 11 figure
Carbon-emcoating architecture boosts lithium storage of Nb2O5
Intercalation transition metal oxides (ITMO) have attracted great attention as lithium-ion battery negative electrodes due to high operation safety, high capacity and rapid ion intercalation. However, the intrinsic low electron conductivity plagues the lifetime and cell performance of the ITMO negative electrode. Here we design a new carbon-emcoating architecture through single CO2 activation treatment as demonstrated by the Nb2O5/C nanohybrid. Triple structure engineering of the carbon-emcoating Nb2O5/C nanohybrid is achieved in terms of porosity, composition, and crystallographic phase. The carbon-embedding Nb2O5/C nanohybrids show superior cycling and rate performance compared with the conventional carbon coating, with reversible capacity of 387 mA h g−1 at 0.2 C and 92% of capacity retained after 500 cycles at 1 C. Differential electrochemical mass spectrometry (DEMS) indicates that the carbon emcoated Nb2O5 nanohybrids present less gas evolution than commercial lithium titanate oxide during cycling. The unique carbon-emcoating technique can be universally applied to other ITMO negative electrodes to achieve high electrochemical performance
White blood cell subsets are associated with carotid intima-media thickness and pulse wave velocity in an older Chinese population: the Guangzhou Biobank Cohort Study
Cross-sectional associations between white blood cell (WBC) count, lymphocyte and granulocyte numbers, and carotid intima-media thickness (IMT) and brachial-ankle pulse wave velocity (PWV) were examined in a novel older Chinese community sample. A total of 817 men and 760 women from a sub-study of the Guangzhou Biobank Cohort Study had a full blood count measured by an automated hematology analyzer, carotid IMT by B-mode ultrasonography and brachial-ankle PWV by a non-invasive automatic waveform analyzer. Following adjustment for confounders, WBC count (β=0.07,
Molecular mechanism underlying differential apoptosis between human melanoma cell lines UACC903 and UACC903(+6) revealed by mitochondria-focused cDNA microarrays
Human malignant melanoma cell line UACC903 is resistant to apoptosis while chromosome 6-mediated suppressed cell line UACC903(+6) is sensitive. Here, we describe identification of differential molecular pathways underlying this difference. Using our recently developed mitochondria-focused cDNA microarrays, we identified 154 differentially expressed genes including proapoptotic (BAK1 [6p21.3], BCAP31, BNIP1, CASP3, CASP6, FAS, FDX1, FDXR, TNFSF10 and VDAC1) and antiapoptotic (BCL2L1, CLN3 and MCL1) genes. Expression of these pro- and anti-apoptotic genes was higher in UACC903(+6) than in UACC903 before UV treatment and was altered after UV treatment. qRT-PCR and Western blots validated microarray results. Our bioinformatic analysis mapped these genes to differential molecular pathways that predict resistance and sensitivity of UACC903 and UACC903(+6) to apoptosis respectively. The pathways were functionally confirmed by the FAS ligand-induced cell death and by siRNA knockdown of BAK1 protein. These results demonstrated the differential molecular pathways underlying survival and apoptosis of UACC903 and UACC903(+6) cell lines
The Azimuthal Decorrelation of Jets Widely Separated in Rapidity
This study reports the first measurement of the azimuthal decorrelation
between jets with pseudorapidity separation up to five units. The data were
accumulated using the D{\O}detector during the 1992--1993 collider run of the
Fermilab Tevatron at 1.8 TeV. These results are compared to
next--to--leading order (NLO) QCD predictions and to two leading--log
approximations (LLA) where the leading--log terms are resummed to all orders in
. The final state jets as predicted by NLO QCD
show less azimuthal decorrelation than the data. The parton showering LLA Monte
Carlo {\small HERWIG} describes the data well; an analytical LLA prediction
based on BFKL resummation shows more decorrelation than the data.Comment: 6 pages with 4 figures, all uuencoded and gzippe
Shrinking a large dataset to identify variables associated with increased risk of Plasmodium falciparum infection in Western Kenya
Large datasets are often not amenable to analysis using traditional single-step approaches. Here, our general objective was to apply imputation techniques, principal component analysis (PCA), elastic net and generalized linear models to a large dataset in a systematic approach to extract the most meaningful predictors for a health outcome. We extracted predictors for Plasmodium falciparum infection, from a large covariate dataset while facing limited numbers of observations, using data from the People, Animals, and their Zoonoses (PAZ) project to demonstrate these techniques: data collected from 415 homesteads in western Kenya, contained over 1500 variables that describe the health, environment, and social factors of the humans, livestock, and the homesteads in which they reside. The wide, sparse dataset was simplified to 42 predictors of P. falciparum malaria infection and wealth rankings were produced for all homesteads. The 42 predictors make biological sense and are supported by previous studies. This systematic data-mining approach we used would make many large datasets more manageable and informative for decision-making processes and health policy prioritization
Neutral Higgs boson pair production via collision in the minimal supersymmetric standard model at linear colliders
We investigate in detail the fusion production mechanisms of
two neutral Higgs bosons (, , and ) within
the framework of the mSUGRA-inspired minimal supersymmetric standard
model(MSSM) at an linear colliders, which provide a probe of the
trilinear Higgs self-couplings. We calculate the dependence of the production
rates on Higgs boson masses, the ratio of the vacuum expectation values and the CMS energy . We find that the cross section for the
production at LC can reach , while the cross section of
production is only under our parameters.Comment: Accepted by Phys. Rev.
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