2,458 research outputs found
Reduced-complexity transmit-beamforming codebook search algorithm
A two-stage reduced-complexity index search algorithm is proposed for finding the best vector in the codebook of quantised equal gain transmission based multiple-input multiple-output arrangements. When the number of transmit antennas is more than three, the normalised complexity is halved while maintaining the same symbol error rate as the benchmark
Safety Practices, Firm Culture, and Workplace Injuries
The authors present analysis of the impact of various HRM practices on firmsâ workersâ compensation costs; specifically, which practices lower firmsâ workersâ compensation costs and whether the impact is the result of changes in technical efficiency or comes through induced changes in workersâ behavior.https://research.upjohn.org/up_press/1037/thumbnail.jp
Human Resource Management and Safety: Technical Efficiency and Economic Incentives
The authors present analysis of the impact of various HRM practices on firmsâ workersâ compensation costs; specifically, which practices lower firmsâ workersâ compensation costs and whether the impact is the result of changes in technical efficiency or comes through induced changes in workersâ behavior.https://research.upjohn.org/up_press/1037/thumbnail.jp
Agency Conflicts, Financial Distress, and Syndicate Structure: Evidence from Japanese Borrowers
We examine how borrower firm characteristics affect the size structure in the Japanese syndicated loan market for the 1999-2003 period. Consistent with the view by Lee and Mullineaux (2004), we find that syndicates are smaller when borrowers have higher credit risk, while firms with greater information asymmetry are associated with larger syndicates in Japan. These results are primarily driven by nonkeiretsu (non-business group) firms. This suggests that the role of enhanced monitoring and facilitated renegotiation is especially useful for banks participating in Japanese syndicated loan for non-keiretsu firms. On the other hand, information problems seem to be less severe for keiretsu (business group) firms which tend to have easier access to syndicated loan via the intermediation of in-house banks in the relevant syndicate. Finally, we find that keiretsu (non-keiretsu) firms have less (more) fraction of loan by their agent banks as the maturity rises. It appears that main banks of keiretsu firms with informational advantage are likely to retain less of the loan and form a more dispersed syndicate to "signal' that the loan is of high quality with increased maturity. This further confirms the view that information problems are less severe in the keiretsu firms.
Probing New Physics by the Tail of the Off-shell Higgs in Mode
Off-shell Higgs at the high mass tail may shed light on the underlying
mechanism of the electroweak symmetry breaking. Due to the large cancellation
in the standard model (SM) between the box and Higgs-mediated triangle
diagrams, the process in the SM is dominated by the
transverse-mode at the high mass tail. The cancellation does not necessarily
hold, when there is a sufficiently large new physics contribution resulting in
longitudinal mode, which is commonly the case when the Higgs sector is
modified. Thus the final states in the high mass tail can be utilized
as a sensitive probe for such models. In the paper we focus on a study of the
process in the fully leptonic decay modes, proposing to utilize the
polarization modes of the off-shell Higgs to probe new physics, whose
contribution mainly shows in the longitudinal mode. As examples, we analyze
three different Higgs sector new physics cases (Higgs portal with a light
scalar, a broad-width scalar that mixes with the Higgs, and quantum critical
Higgs models), and demonstrate that the angular information relating to the
polarization serves as very sensitive probe for such new physics.Comment: 6 pages, 2 figures, 1 tabl
Crystallography on Curved Surfaces
We study static and dynamical properties that distinguish two dimensional
crystals constrained to lie on a curved substrate from their flat space
counterparts. A generic mechanism of dislocation unbinding in the presence of
varying Gaussian curvature is presented in the context of a model surface
amenable to full analytical treatment. We find that glide diffusion of isolated
dislocations is suppressed by a binding potential of purely geometrical origin.
Finally, the energetics and biased diffusion dynamics of point defects such as
vacancies and interstitials is explained in terms of their geometric potential.Comment: 12 Pages, 8 Figure
Ubiquitin-dependent proteasomal degradation of AMPK gamma subunit by Cereblon inhibits AMPK activity
Cereblon (CRBN), a substrate receptor for Cullin-ring E3 ubiquitin ligase (CRL), is a major target protein of immunomodulatory drugs. An earlier study demonstrated that CRBN directly interacts with the catalytic α subunit of AMP-activated protein kinase (AMPK), a master regulator of energy homeostasis, down-regulating the enzymatic activity of AMPK. However, it is not clear how CRBN modulates AMPK activity. To investigate the mechanism of CRBN-dependent AMPK inhibition, we measured protein levels of each AMPK subunit in brains, livers, lungs, hearts, spleens, skeletal muscles, testes, kidneys, and embryonic fibroblasts from wild-type and Crbn^(â/â) mice. Protein levels and stability of the regulatory AMPKÎł subunit were increased in Crbn^(â/â) mice. Increased stability of AMPKÎł in Crbn^(â/â) MEFs was dramatically reduced by exogenous expression of Crbn. In wild-type MEFs, the proteasomal inhibitor MG132 blocked degradation of AMPKÎł. We also found that CRL4^(CRBN) directly ubiquitinated AMPKÎł. Taken together, these findings suggest that CRL4^(CRBN) regulates AMPK through ubiquitin-dependent proteasomal degradation of AMPKÎł
Orbital Stark effect and quantum confinement transition of donors in silicon
Adiabatic shuttling of single impurity bound electrons to gate induced
surface states in semiconductors has attracted much attention in recent times,
mostly in the context of solid-state quantum computer architecture. A recent
transport spectroscopy experiment for the first time was able to probe the
Stark shifted spectrum of a single donor in silicon buried close to a gate.
Here we present the full theoretical model involving large-scale quantum
mechanical simulations that was used to compute the Stark shifted donor states
in order to interpret the experimental data. Use of atomistic tight-binding
technique on a domain of over a million atoms helped not only to incorporate
the full band structure of the host, but also to treat realistic device
geometries and donor models, and to use a large enough basis set to capture any
number of donor states. The method yields a quantitative description of the
symmetry transition that the donor electron undergoes from a 3D Coulomb
confined state to a 2D surface state as the electric field is ramped up
adiabatically. In the intermediate field regime, the electron resides in a
superposition between the states of the atomic donor potential and that of the
quantum dot like states at the surface. In addition to determining the effect
of field and donor depth on the electronic structure, the model also provides a
basis to distinguish between a phosphorus and an arsenic donor based on their
Stark signature. The method also captures valley-orbit splitting in both the
donor well and the interface well, a quantity critical to silicon qubits. The
work concludes with a detailed analysis of the effects of screening on the
donor spectrum.Comment: 10 pages, 10 figures, journa
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