6,163 research outputs found
Consistency conditions for regulatory analysis of financial institutions: a comparison of frontier efficiency methods
We propose a set of consistency conditions that frontier efficiency measures should meet to be most useful for regulatory analysis or other purposes. The efficiency estimates should be consistent in their efficiency levels, rankings, and identification of best and worst firms, consistent over time and with competitive conditions in the market, and consistent with standard nonfrontier measures of performance. We provide evidence on these conditions by evaluating and comparing efficiency estimates on U.S. bank efficiency from variants of all four of the major approaches -- DEA, SFA, TFA, and DFA -- and find mixed results.Financial institutions ; Bank supervision
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Optimizing Data Management with Disparities in Data Value
When there is a disparity in the value of different data records and fields, there is a need for an optimization of data resources. Not all data necessarily contribute the same value. It depends on the usage of the data, as well as a variety of other factors. This paper presents models for optimizing data management in the presence of a disparity between the values contributed by different data. We expound on what disparity of data value represents and illustrate models to derive a numerical measure of such disparity. We then use real-world data from a large data resource used to manage alumni relations, and demonstrate our optimization methods and results. We then discuss the tradeoffs involved between value and cost, and the implications for data management, both in this real-world context and in general
Incommensurate magnetic ordering in Cu2Te2O5X2 (X=Cl, Br) studied by single crystal neutron diffraction
Polarized and unpolarized neutron diffraction studies have been carried out
on single crystals of the coupled spin tetrahedra systems Cu2Te2O5X2 (X=Cl,
Br). A model of the magnetic structure associated with the propagation vectors
k'Cl ~ -0.150,0.422,1/2 and k'Br ~ -0.172,0.356,1/2 and stable below TN=18 K
for X=Cl and TN=11 K for X=Br is proposed. A feature of the model, common to
both the bromide and chloride, is a canted coplanar motif for the 4 Cu2+ spins
on each tetrahedron which rotates on a helix from cell to cell following the
propagation vector. The Cu2+magnetic moment determined for X=Br, 0.395(5)muB,
is significantly less than for X=Cl, 0.88(1)muB at 2K. The magnetic structure
of the chloride associated with the wave-vector k' differs from that determined
previously for the wave vector k~0.150,0.422,1/2 [O. Zaharko et.al. Phys. Rev.
Lett. 93, 217206 (2004)]
Quantitative single-molecule microscopy reveals that CENP-A(Cnp1) deposition occurs during G2 in fission yeast
The inheritance of the histone H3 variant CENP-A in nucleosomes at centromeres following DNA replication is mediated by an epigenetic mechanism. To understand the process of epigenetic inheritance, or propagation of histones and histone variants, as nucleosomes are disassembled and reassembled in living eukaryotic cells, we have explored the feasibility of exploiting photo-activated localization microscopy (PALM). PALM of single molecules in living cells has the potential to reveal new concepts in cell biology, providing insights into stochastic variation in cellular states. However, thus far, its use has been limited to studies in bacteria or to processes occurring near the surface of eukaryotic cells. With PALM, one literally observes and 'counts' individual molecules in cells one-by-one and this allows the recording of images with a resolution higher than that determined by the diffraction of light (the so-called super-resolution microscopy). Here, we investigate the use of different fluorophores and develop procedures to count the centromere-specific histone H3 variant CENP-A(Cnp1) with single-molecule sensitivity in fission yeast (Schizosaccharomyces pombe). The results obtained are validated by and compared with ChIP-seq analyses. Using this approach, CENP-A(Cnp1) levels at fission yeast (S. pombe) centromeres were followed as they change during the cell cycle. Our measurements show that CENP-A(Cnp1) is deposited solely during the G2 phase of the cell cycle
Short GRB 130603B: Discovery of a jet break in the optical and radio afterglows, and a mysterious late-time X-ray excess
We present radio, optical/NIR, and X-ray observations of the afterglow of the
short-duration 130603B, and uncover a break in the radio and optical bands at
0.5 d after the burst, best explained as a jet break with an inferred jet
opening angle of 4-8 deg. GRB 130603B is only the third short GRB with a radio
afterglow detection to date, and the first time that a jet break is evident in
the radio band. We model the temporal evolution of the spectral energy
distribution to determine the burst explosion properties and find an
isotropic-equivalent kinetic energy of (0.6-1.7) x 10^51 erg and a circumburst
density of 5 x 10^-3-30 cm^-3. From the inferred opening angle of GRB 130603B,
we calculate beaming-corrected energies of Egamma (0.5-2) x 10^49 erg and EK
(0.1-1.6) x 10^49 erg. Along with previous measurements and lower limits we
find a median short GRB opening angle of 10 deg. Using the all-sky observed
rate of 10 Gpc^-3 yr^-1, this implies a true short GRB rate of 20 yr^-1 within
200 Mpc, the Advanced LIGO/VIRGO sensitivity range for neutron star binary
mergers. Finally, we uncover evidence for significant excess emission in the
X-ray afterglow of GRB 130603B at >1 d and conclude that the additional energy
component could be due to fall-back accretion or spin-down energy from a
magnetar formed following the merger.Comment: Submitted to ApJ; emulateapj style; 10 pages, 1 table, 3 figure
Terahertz imaging and spectroscopy of large-area single-layer graphene
We demonstrate terahertz (THz) imaging and spectroscopy of a 15x15-mm^2
single-layer graphene film on Si using broadband THz pulses. The THz images
clearly map out the THz carrier dynamics of the graphene-on-Si sample, allowing
us to measure sheet conductivity with sub-mm resolution without fabricating
electrodes. The THz carrier dynamics are dominated by intraband transitions and
the THz-induced electron motion is characterized by a flat spectral response. A
theoretical analysis based on the Fresnel coefficients for a metallic thin film
shows that the local sheet conductivity varies across the sample from {\sigma}s
= 1.7x10^-3 to 2.4x10^-3 {\Omega}^-1 (sheet resistance, {\rho}s = 420 - 590
{\Omega}/sq).Comment: 6 pages, 5 figure
MsrR contributes to cell surface characteristics and virulence in Staphylococcus aureus
MsrR, a factor contributing to methicillin resistance in Staphylococcus aureus, belongs to the LytR-CpsA-Psr family of cell envelope-associated proteins. Deletion of msrR increased cell size and aggregation, and altered envelope properties, leading to a temporary reduction in cell surface hydrophobicity, diminished colony-spreading ability, and an increased susceptibility to Congo red. The reduced phosphorus content of purified cell walls of the msrR mutant suggested a reduction in wall teichoic acids, which may explain some of the observed phenotypes. Microarray analysis of the msrR deletion mutant revealed only minor changes in the global transcriptome, suggesting that MsrR has structural rather than regulatory functions. Importantly, virulence of the msrR mutant was decreased in a nematode-killing assay as well as in rat experimental endocarditis. MsrR is therefore likely to play a role in cell envelope maintenance, cell separation, and pathogenicity of S. aureu
Antitumor Activity of Pembrolizumab in Biomarker-Unselected Patients With Recurrent and/or Metastatic Head and Neck Squamous Cell Carcinoma: Results From the Phase Ib KEYNOTE-012 Expansion Cohort.
Purpose Treatment with pembrolizumab, an anti-programmed death-1 antibody, at 10 mg/kg administered once every 2 weeks, displayed durable antitumor activity in programmed death-ligand 1 (PD-L1) -positive recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) in the KEYNOTE-012 trial. Results from the expansion cohort, in which patients with HNSCC, irrespective of biomarker status, received a fixed dose of pembrolizumab at a less frequent dosing schedule, are reported. Patients and Methods Patients with R/M HNSCC, irrespective of PD-L1 or human papillomavirus status, received pembrolizumab 200 mg intravenously once every 3 weeks. Imaging was performed every 8 weeks. Primary end points were overall response rate (ORR) per central imaging vendor (Response Evaluation Criteria in Solid Tumors v1.1) and safety. Secondary end points included progression-free survival, overall survival, and association of response and PD-L1 expression. Patients who received one or more doses of pembrolizumab were included in analyses. Results Of 132 patients enrolled, median age was 60 years (range, 25 to 84 years), 83% were male, and 57% received two or more lines of therapy for R/M disease. ORR was 18% (95% CI, 12 to 26) by central imaging vendor and 20% (95% CI, 13 to 28) by investigator review. Median duration of response was not reached (range, ≥ 2 to ≥ 11 months). Six-month progression-free survival and overall survival rates were 23% and 59%, respectively. By using tumor and immune cells, a statistically significant increase in ORR was observed for PD-L1-positive versus -negative patients (22% v 4%; P = .021). Treatment-related adverse events of any grade and grade ≥ 3 events occurred in 62% and 9% of patients, respectively. Conclusion Fixed-dose pembrolizumab 200 mg administered once every 3 weeks was well tolerated and yielded a clinically meaningful ORR with evidence of durable responses, which supports further development of this regimen in patients with advanced HNSCC
Revision rates after primary hip and knee replacement in England between 2003 and 2006
<b>Background</b>:
Hip and knee replacement are some of the most frequently performed surgical procedures in the world. Resurfacing of the hip and unicondylar knee replacement are increasingly being used. There is relatively little evidence on their performance. To study performance of joint replacement in England, we investigated revision rates in the first 3 y after hip or knee replacement according to prosthesis type.
<b>Methods and Findings</b>:
We linked records of the National Joint Registry for England and Wales and the Hospital Episode Statistics for patients with a primary hip or knee replacement in the National Health Service in England between April 2003 and September 2006. Hospital Episode Statistics records of succeeding admissions were used to identify revisions for any reason. 76,576 patients with a primary hip replacement and 80,697 with a primary knee replacement were included (51% of all primary hip and knee replacements done in the English National Health Service). In hip patients, 3-y revision rates were 0.9% (95% confidence interval [CI] 0.8%–1.1%) with cemented, 2.0% (1.7%–2.3%) with cementless, 1.5% (1.1%–2.0% CI) with “hybrid” prostheses, and 2.6% (2.1%–3.1%) with hip resurfacing (p < 0.0001). Revision rates after hip resurfacing were increased especially in women. In knee patients, 3-y revision rates were 1.4% (1.2%–1.5% CI) with cemented, 1.5% (1.1%–2.1% CI) with cementless, and 2.8% (1.8%–4.5% CI) with unicondylar prostheses (p < 0.0001). Revision rates after knee replacement strongly decreased with age.
<b>Interpretation</b>:
Overall, about one in 75 patients needed a revision of their prosthesis within 3 y. On the basis of our data, consideration should be given to using hip resurfacing only in male patients and unicondylar knee replacement only in elderly patients
The Mixmaster Universe in Five Dimensions
We consider a five dimensional vacuum cosmology with Bianchi type-IX spatial
geometry and an extra non-compact coordinate. Finding a new class of solutions,
we examine and rule out the possibility of deterministic chaos. We interpret
this result within the context of induced matter theory.Comment: 13 page
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