1,258 research outputs found
Electron spin phase relaxation of phosphorus donors in nuclear spin enriched silicon
We report a pulsed EPR study of the phase relaxation of electron spins bound
to phosphorus donors in isotopically purified 29^Si and natural abundance Si
single crystals measured at 8 K.Comment: 5 pages, 3 figure
Drell-Yan Production of Z' in the Three-Site Higgsless Model at the LHC
In the Higgsless models, there are extra gauge bosons which keep the
perturbative unitarity of a longitudinally polarized gauge boson. The
three-site Higgsless model is a minimal Higgsless model and contains three
extra gauge bosons, and Z'. In this paper, we report the
discovery potential of the Z' gauge boson via Drell-Yan production with
Z'(mass=380, 500, 600 GeV) (,
) at the LHC (=14 TeV).Comment: 7 pages, 5 figures included. References revise
High-pressure droplet combustion studies
This is a joint research program, pursued by investigators at the University of Tokyo, UCSD, and NASA Lewis Research Center. The focus is on high-pressure combustion of miscible binary fuel droplets. It involves construction of an experimental apparatus in Tokyo, mating of the apparatus to a NASA-Lewis 2.2-second drop-tower frame in San Diego, and performing experiments in the 2.2-second tower in Cleveland, with experimental results analyzed jointly by the Tokyo, UCSD, and NASA investigators. The project was initiated in December, 1990 and has now involved three periods of drop-tower testing by Mikami at Lewis. The research accomplished thus far concerns the combustion of individual fiber-supported droplets of mixtures of n-heptane and n-hexadecane, initially about 1 mm diameter, under free-fall microgravity conditions. Ambient pressures ranged up to 3.0 MPa, extending above the critical pressures of both pure fuels, in room-temperature nitrogen-oxygen atmospheres having oxygen mole fractions X of 0.12 and 0.13. The general objective is to study near-critical and super-critical combustion of these droplets and to see whether three-stage burning, observed at normal gravity, persists at high pressures in microgravity. Results of these investigations will be summarized here; a more complete account soon will be published
Evaluation of the Vulnerability of Speaker Verification to Synthetic Speech
In this paper, we evaluate the vulnerability of a speaker verification
(SV) system to synthetic speech. Although this problem
was first examined over a decade ago, dramatic improvements
in both SV and speech synthesis have renewed interest in
this problem. We use a HMM-based speech synthesizer, which
creates synthetic speech for a targeted speaker through adaptation
of a background model and a GMM-UBM-based SV system.
Using 283 speakers from the Wall-Street Journal (WSJ)
corpus, our SV system has a 0.4% EER. When the system
is tested with synthetic speech generated from speaker models
derived from the WSJ journal corpus, 90% of the matched
claims are accepted. This result suggests a possible vulnerability
in SV systems to synthetic speech. In order to detect
synthetic speech prior to recognition, we investigate the
use of an automatic speech recognizer (ASR), dynamic-timewarping
(DTW) distance of mel-frequency cepstral coefficients
(MFCC), and previously-proposed average inter-frame difference
of log-likelihood (IFDLL). Overall, while SV systems
have impressive accuracy, even with the proposed detector,
high-quality synthetic speech can lead to an unacceptably high
acceptance rate of synthetic speakers
How is Death Hastening Done? A Review of Existing Sanctioned Death Hastening Decision-Making Processes and Practices
Death hastening is a controversial terminal care option that is currently carried out in only four countries and some US states, with Canada posed to allow it on June 6, 2016. This article focuses on how assisted suicide and euthanasia have been managed in the four countries and US states where it has been sanctioned and practiced. A systematic literature review and additional searches were employed to gain information on the methods, recipients, procedures, regulations, outcomes, and other information available on state-sanctioned death hastening. The findings reveal many different possible models and thus considerations required for planning in advance of death hastening actually occurring.  
RAS mutation status predicts survival and patterns of recurrence in patients undergoing hepatectomy for colorectal liver metastases.
ObjectiveTo determine the impact of RAS mutation status on survival and patterns of recurrence in patients undergoing curative resection of colorectal liver metastases (CLM) after preoperative modern chemotherapy.BackgroundRAS mutation has been reported to be associated with aggressive tumor biology. However, the effect of RAS mutation on survival and patterns of recurrence after resection of CLM remains unclear.MethodsSomatic mutations were analyzed using mass spectroscopy in 193 patients who underwent single-regimen modern chemotherapy before resection of CLM. The relationship between RAS mutation status and survival outcomes was investigated.ResultsDetected somatic mutations included RAS (KRAS/NRAS) in 34 (18%), PIK3CA in 13 (7%), and BRAF in 2 (1%) patients. At a median follow-up of 33 months, 3-year overall survival (OS) rates were 81% in patients with wild-type versus 52.2% in patients with mutant RAS (P = 0.002); 3-year recurrence-free survival (RFS) rates were 33.5% with wild-type versus 13.5% with mutant RAS (P = 0.001). Liver and lung recurrences were observed in 89 and 83 patients, respectively. Patients with RAS mutation had a lower 3-year lung RFS rate (34.6% vs 59.3%, P < 0.001) but not a lower 3-year liver RFS rate (43.8% vs 50.2%, P = 0.181). In multivariate analyses, RAS mutation predicted worse OS [hazard ratio (HR) = 2.3, P = 0.002), overall RFS (HR = 1.9, P = 0.005), and lung RFS (HR = 2.0, P = 0.01), but not liver RFS (P = 0.181).ConclusionsRAS mutation predicts early lung recurrence and worse survival after curative resection of CLM. This information may be used to individualize systemic and local tumor-directed therapies and follow-up strategies
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