245 research outputs found
Applicability of the High Field Model: A Preliminary Numerical Study
In a companion presentation, we have discussed the theory of a mesoscopic/
macroscopic model, which can be viewed as an augmented drift-diffusion model. Here,
we describe how that model is used. The device we consider for this presentation is the
one dimensional GaAs n+ânân+ structure of length 0.8ÎŒm. First, a full Hydro-
Dynamic (HD) model, proven reliable when compared with Monte Carlo simulations, is
used to simulate the device via the ENO finite difference method. As applied to the full
device, the new model is not necessarily superior to traditional Drift-Diffusion (DD).
Indeed, when we plot the quantity η=âÎŒ0E/kT0/m, where ÎŒ0 is the mobility constant
and E=âÏâČ is the electric field, we verify that the high field assumption η âș 1, required
for the high field model, is satisfied only in an interval given approximately by [0.2, 0.5].
When we run both the DD model and the new high field model in this restricted interval,
with boundary conditions of concentration n and potential Ï provided by the HD
results, we demonstrate that the new model outperforms the DD model. This indicates
that the high field and DD models should be used only in parts of the device, connected
by a transition kinetic regime. This will be a domain decomposition issue involving
interface conditions and adequate numerical methods
A Comprehensive Fluid Dynamic and Geometric Study for an â In-Vitro â Comparison of Four Surgically Implanted Pericardial Stented Valves
Call and be counted! Can we reliably estimate the number of callers in the indri's (Indri indri) song?
Test of large area glass RPCs at the DA Phi NE Test Beam Facility (BTF)
Abstract The CaPiRe program has been started to develop a new detector design, in order to produce large areas of glass Resistive Plate Chambers (RPC) detectors, overcoming the previous limitations. As a first step we produced our glass RPC detectors ( 1 m 2 ) at General Tecnica exploiting their standard procedures, materials and production techniques simply using 2 mm glass electrodes instead of the bakelite ones. A set of RPC was produced by using pre-coated (silk screen printed) electrodes, while others were produced with the standard graphite coating. All the detectors, together with four old Glass RPC acting as reference, were tested at the DA Ί NE Test Beam Facility with 500 MeV electrons in order to study the efficiency in different positions inside the detectors (i.e. near spacers and edges) and to study the detector behavior as a function of the local particle rate
Research perspectives in the etiology of congenital anorectal malformations using data of the International Consortium on Anorectal Malformations: evidence for risk factors across different populations
Contains fulltext :
89406.pdf (publisher's version ) (Closed access)PURPOSE: The recently established International Consortium on Anorectal Malformations aims to identify genetic and environmental risk factors in the etiology of syndromic and nonsyndromic anorectal malformations (ARM) by promoting collaboration through data sharing and combined research activities. METHODS: The consortium attempts to recruit at least 1,000 ARM cases. DNA samples are collected from case-parent triads to identify genetic factors involved in ARM. Several genetic techniques will be applied, including SNP arrays, gene and whole exome sequencing, and a genome-wide association study. Questionnaires inquiring about circumstances before and during pregnancy will be used to obtain environmental risk factor data. RESULTS: Currently, 701 ARM cases have been recruited throughout Europe. Clinical data are available from all cases, and DNA samples and questionnaire data mainly from the Dutch and German cases. Preliminary analyses on environmental risk factors in the Dutch and German cohort found associations between ARM and family history of ARM, fever during first trimester of pregnancy and maternal job exposure to cleaning agents and solvents. CONCLUSION: First results show that both genetic and environmental factors may contribute to the multifactorial etiology of ARM. The International Consortium on Anorectal Malformations will provide possibilities to study and detect important genes and environmental risk factors for ARM, ultimately resulting in better genetic counseling, improved therapies, and primary prevention.1 november 201
Evidence for an excess of B -> D(*) Tau Nu decays
Based on the full BaBar data sample, we report improved measurements of the
ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or
mu. These ratios are sensitive to new physics contributions in the form of a
charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) =
0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0
sigma and 2.7 sigma, respectively. Taken together, our results disagree with
these expectations at the 3.4 sigma level. This excess cannot be explained by a
charged Higgs boson in the type II two-Higgs-doublet model. We also report the
observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the
format of Figure 2 and included the effect of the change of the Tau
polarization due to the charged Higg
Search for the decay modes D^0 â e^+e^-, D^0 â ÎŒ^+ÎŒ^-, and D^0 â e^±Όâ
We present searches for the rare decay modes D^0âe^+e^-, D^0âÎŒ^+ÎŒ^-, and D^0âe^±Ό^â in continuum e^+e^-âcc events recorded by the BABAR detector in a data sample that corresponds to an integrated luminosity of 468ââfb^(-1). These decays are highly GlashowâIliopoulosâMaiani suppressed but may be enhanced in several extensions of the standard model. Our observed event yields are consistent with the expected backgrounds. An excess is seen in the D^0âÎŒ^+ÎŒ^- channel, although the observed yield is consistent with an upward background fluctuation at the 5% level. Using the FeldmanâCousins method, we set the following 90% confidence level intervals on the branching fractions: B(D^0âe^+e^-)<1.7Ă10^(-7), B(D^0âÎŒ^+ÎŒ^-) within [0.6,8.1]Ă10^(-7), and B(D^0âe^±Ό^â)<3.3Ă10^(-7)
Serum cholesterol levels, HMG-CoA reductase inhibitors and the risk of intracerebral haemorrhage. the Multicenter Study on Cerebral Haemorrhage in Italy (MUCH-Italy)
Bottomonium spectroscopy and radiative transitions involving the chi(bJ)(1P, 2P) states at BABAR
We use (121 +/- 1) million Upsilon(3S) and (98 +/- 1) million Upsilon(2S) mesons recorded by the BABAR detector at the PEP-II e(+)e(-) collider at SLAC to perform a study of radiative transitions involving the chi(bJ)(1P, 2P) states in exclusive decays with mu(+)mu(-)gamma gamma final states. We reconstruct twelve channels in four cascades using two complementary methods. In the first we identify both signal photon candidates in the electromagnetic calorimeter (EMC), employ a calorimeter timing-based technique to reduce backgrounds, and determine branching-ratio products and fine mass splittings. These results include the best observational significance yet for the chi(b0)(2P) -> gamma Upsilon(2S) and chi(b0)(1P) -> gamma Upsilon(1S) transitions. In the second method, we identify one photon candidate in the EMC and one which has converted into an e(+)e(-) pair due to interaction with detector material, and we measure absolute product branching fractions. This method is particularly useful for measuring Upsilon(3S) -> gamma chi(b1,2)(1P) decays. Additionally, we provide the most up-to-date derived branching fractions, matrix elements and mass splittings for chi(b) transitions in the bottomonium system. Using a new technique, we also measure the two lowest-order spin-dependent coefficients in the nonrelativistic QCD Hamiltonian
Measurements of the leptonic branching fractions of the
Data collected with the DELPHI detector from 1993 to 1995 combined with previous DELPHI results for data from 1991 and 1992 yield the branching fractions B({\tau \rightarrow \mbox{\rm e} \nu \bar{\nu}}) = (17.877 \pm 0.109_{stat} \pm 0.110_{sys} )\% and
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