10,714 research outputs found
Analysis of the Q^2-dependence of charged-current quasielastic processes in neutrino-nucleus interactions
We discuss the observed disagreement between the Q^2 distributions of
neutrino-nucleus quasielastic events, measured by a number of recent
experiments, and the predictions of Monte Carlo simulations based on the
relativistic Fermi gas model. The results of our analysis suggest that these
discrepancies are likely to be ascribable to both the breakdown of the impulse
approximation and the limitations of the Fermi gas description. Several issues
related to the extraction of the Q^2 distributions from the experimental data
are also discussed, and new kinematical variables, which would allow for an
improved analysis, are proposed.Comment: 8 pages, 8 figures, 1 tabl
Flowfield-dependent variant method for moving-boundary problems
A novel numerical scheme using the combination of flowfield-dependent variation method and arbitrary Lagrangian–Eulerian method is developed. This method is a mixed explicit–implicit numerical scheme, and its implicitness is dependent on the physical properties of the flowfield. The scheme is discretized using the finite-volume method to give flexibility in dealing with complicated geometries. The formulation itself yields a sparse matrix, which can be solved by using any iterative algorithm. Several benchmark problems in two-dimensional inviscid and viscous flow have been selected to validate the method. Good agreement with available experimental and numerical data in the literature has been obtained, thus showing its promising application in complex fluid–structure interaction problems
Variation in annual volume at a university hospital does not predict mortality for pancreatic resections.
Annual volume of pancreatic resections has been shown to affect mortality rates, prompting recommendations to regionalize these procedures to high-volume hospitals. Implementation has been difficult, given the paucity of high-volume centers and the logistical hardships facing patients. Some studies have shown that low-volume hospitals achieve good outcomes as well, suggesting that other factors are involved. We sought to determine whether variations in annual volume affected patient outcomes in 511 patients who underwent pancreatic resections at the University of California, San Francisco between 1990 and 2005. We compared postoperative mortality and complication rates between low, medium, or high volume years, designated by the number of resections performed, adjusting for patient characteristics. Postoperative mortality rates did not differ between high volume years and medium/low volume years. As annual hospital volume of pancreatic resections may not predict outcome, identification of actual predictive factors may allow low-volume centers to achieve excellent outcomes
Electronic Properties of Strained Si/Ge Core-Shell Nanowires
We investigated the electronic properties of strained Si/Ge core-shell
nanowires along the [110] direction using first principles calculations based
on density-functional theory. The diameter of the studied core-shell wire is up
to 5 nm. We found the band gap of the core-shell wire is smaller than that of
both pure Si and Ge wires with the same diameter. This reduced band gap is
ascribed to the intrinsic strain between Ge and Si layers, which partially
counters the quantum confinement effect. The external strain is further applied
to the nanowires for tuning the band structure and band gap. By applying
sufficient tensile strain, we found the band gap of Si-core/Ge-shell nanowire
with diameter larger than ~3 nm experiences a transition from direct to
indirect gap.Comment: 4 figure
Employee attitudes as a mediator between HRM and organizational performance
Attitude is a power that controls human behaviour. When employee Attitude is positive, it can give impact positive to organization performance. A proper human resource management (HRM) managed by organization, the employee attitude will be affected. HRM practices influence employee attitude positively and there is a mediating role of employee attitude between training and development dimension of HRM practices and organizational performance. Therefore, the purpose of this study is to explore employee atttiude as a mediator between HRM and organizational performance. A sample of this study was 219 respondents from employee construction in Libya. The data was analyzed using structural equation modelling (SEM) approach. This study showed that employee attitudes is a full mediator between relationship HRM and organizational performance. Therefore, HRM practices influence employee attitude and its give impact to organizational performance for more effective and efficient in achieving organization goal
Bimodality in low-luminosity E and S0 galaxies
Stellar population characteristics are presented for a sample of low-luminosity early-type galaxies (LLEs) in order to compare them with their more luminous counterparts. Long-slit spectra of a sample of 10 LLEs were taken with the ESO New Technology Telescope, selected for their low luminosities. Line strengths were measured on the Lick standard system. Lick indices for these LLEs were correlated with velocity dispersion (σ), alongside published data for a variety of Hubble types. The LLEs were found to fall below an extrapolation of the correlation for luminous ellipticals and were consistent with the locations of spiral bulges in plots of line strengths versus σ. Luminosity weighted average ages, metallicities and abundance ratios were estimated from χ2 fitting of 19 Lick indices to predictions from simple stellar population models. The LLEs appear younger than luminous ellipticals and of comparable ages to spiral bulges. These LLEs show a bimodal metallicity distribution, consisting of a low-metallicity group (possibly misclassified dwarf spheroidal galaxies) and a high-metallicity group (similar to spiral bulges). Finally, they have low α-element to iron peak abundance ratios indicative of slow, extended star formation
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