17,474 research outputs found
Hadronic B Decays to Charmless VT Final States
Charmless hadronic decays of B mesons to a vector meson (V) and a tensor
meson (T) are analyzed in the frameworks of both flavor SU(3) symmetry and
generalized factorization. We also make comments on B decays to two tensor
mesons in the final states. Certain ways to test validity of the generalized
factorization are proposed, using decays. We calculate the branching
ratios and CP asymmetries using the full effective Hamiltonian including all
the penguin operators and the form factors obtained in the non-relativistic
quark model of Isgur, Scora, Grinstein and Wise.Comment: 27 pages, no figures, LaTe
Calibration of Distributionally Robust Empirical Optimization Models
We study the out-of-sample properties of robust empirical optimization
problems with smooth -divergence penalties and smooth concave objective
functions, and develop a theory for data-driven calibration of the non-negative
"robustness parameter" that controls the size of the deviations from
the nominal model. Building on the intuition that robust optimization reduces
the sensitivity of the expected reward to errors in the model by controlling
the spread of the reward distribution, we show that the first-order benefit of
``little bit of robustness" (i.e., small, positive) is a significant
reduction in the variance of the out-of-sample reward while the corresponding
impact on the mean is almost an order of magnitude smaller. One implication is
that substantial variance (sensitivity) reduction is possible at little cost if
the robustness parameter is properly calibrated. To this end, we introduce the
notion of a robust mean-variance frontier to select the robustness parameter
and show that it can be approximated using resampling methods like the
bootstrap. Our examples show that robust solutions resulting from "open loop"
calibration methods (e.g., selecting a confidence level regardless of
the data and objective function) can be very conservative out-of-sample, while
those corresponding to the robustness parameter that optimizes an estimate of
the out-of-sample expected reward (e.g., via the bootstrap) with no regard for
the variance are often insufficiently robust.Comment: 51 page
Critical currents for vortex defect motion in superconducting arrays
We study numerically the motion of vortices in two-dimensional arrays of
resistively shunted Josephson junctions. An extra vortex is created in the
ground states by introducing novel boundary conditions and made mobile by
applying external currents. We then measure critical currents and the
corresponding pinning energy barriers to vortex motion, which in the
unfrustrated case agree well with previous theoretical and experimental
findings. In the fully frustrated case our results also give good agreement
with experimental ones, in sharp contrast with the existing theoretical
prediction. A physical explanation is provided in relation with the vortex
motion observed in simulations.Comment: To appear in Physical Review
Investigation of single nucleotide polymorphisms in porcine candidate genes for blood component traits in pigs
This study used 209 public single nucleotide polymorphism (SNP) arrays for 151 candidate genes of pigs to analyse their association with nine blood component traits (insulin-like growth factor-I, insulin, immuno globulin, lymphocyte, monocyte, eosinophil, basophil, neutrophil and atypical lymph) in 209 Korean native pigs and Yorkshire F2 hybrids. Of these, 52 SNPs in 49 candidate genes showed significant association with one or more blood component traits. Nineteen of these SNPs were found to be present in blood component QTL regions. The 49 candidate genes corresponding to 52 SNPs with significant effects were detected and used for gene ontology analysis to understand the function of the candidate genes at molecular level. Based on functional classification (biological process, cellular components, and molecular function) of annotated candidates, 34 candidate genes (11 genes of IGF-1, 9 of IS, 9 of IG, 6 of NP, and 3 of EP) were detected. Additionally, eight genes (PSMB4, PSME3, MAPKAPK3, CTLA4, CUL7, GGT1, IDH3B, and RXRB) interacting with four immune pathways (immune system, adaptive immune system, Class I MHC-mediated antigen processing and presentation, and antigen processing: ubiquitination and proteasome degradation) were found through pathway and network analyses. The eight candidate genes identified in this study are included in class I MHC-mediated antigen pathway, which is an important factor that determines the success of organ transplantation in addition to the improvement of diseases and immunity of pigs. Therefore, these genes can potentially be used in heterogeneous organ research in future research.Keywords: Association analysis, gene network, pathway, SNP, swin
Defect Motion and Lattice Pinning Barrier in Josephson-Junction Ladders
We study motion of domain wall defects in a fully frustrated
Josephson-unction ladder system, driven by small applied currents. For small
system sizes, the energy barrier E_B to the defect motion is computed
analytically via symmetry and topological considerations. More generally, we
perform numerical simulations directly on the equations of motion, based on the
resistively-shunted junction model, to study the dynamics of defects, varying
the system size. Coherent motion of domain walls is observed for large system
sizes. In the thermodynamical limit, we find E_B=0.1827 in units of the
Josephson coupling energy.Comment: 7 pages, and to apear in Phys. Rev.
Public e-procurement
노트 : 3rd International Public Procurement Conference Proceeding
Investigation of thermal resistance and power consumption in Ga-doped indium oxide (In2O3) nanowire phase change random access memory
The resistance stability and thermal resistance of phase change memory devices using similar to 40 nm diameter Ga-doped In2O3 nanowires (Ga:In2O3 NW) with different Ga-doping concentrations have been investigated. The estimated resistance stability (R(t)/R-0 ratio) improves with higher Ga concentration and is dependent on annealing temperature. The extracted thermal resistance (R-th) increases with higher Ga-concentration and thus the power consumption can be reduced by similar to 90% for the 11.5% Ga: In2O3 NW, compared to the 2.1% Ga: In2O3 NW. The excellent characteristics of Ga-doped In2O3 nanowire devices offer an avenue to develop low power and reliable phase change random access memory applications. (C) 2014 AIP Publishing LLC.X113sciescopu
ELECTROMYOGRAPHY AND KINEMATIC CHARACTERISTICS OF OBSTACLE GAIT IN ELDERLY PARKINSON’S PATIENTS
INTRODUCTION: Falls associated with tripping over an obstacle can be dangerous, yet little is known about the strategies used for stepping over obstacles in elderly Parkinson's patients. The purpose of this study was to investigate the lower extremity muscle activity and kinematics of obstacle gait in Parkinson's patients
Observation of First-Order Metal-Insulator Transition without Structural Phase Transition in VO_2
An abrupt first-order metal-insulator transition (MIT) without structural
phase transition is first observed by current-voltage measurements and
micro-Raman scattering experiments, when a DC electric field is applied to a
Mott insulator VO_2 based two-terminal device. An abrupt current jump is
measured at a critical electric field. The Raman-shift frequency and the
bandwidth of the most predominant Raman-active A_g mode, excited by the
electric field, do not change through the abrupt MIT, while, they, excited by
temperature, pronouncedly soften and damp (structural MIT), respectively. This
structural MIT is found to occur secondarily.Comment: 4 pages, 4 figure
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