291 research outputs found
Analytic many-body potential for GaAs(001) homoepitaxy: Bulk and surface properties
We employ atomic-scale simulation methods to investigate bulk and surface properties of an analytic Tersoff- Abell type potential for describing interatomic interactions in GaAs. The potential is a modified form of that proposed by Albe and colleagues [Phys. Rev. B 66, 035205 (2002)] in which the cut-off parameters for the As-As interaction have been shortened.With this modification, many bulk properties predicted by the potential for solid GaAs are the same as those in the original potential, but properties of the GaAs(001) surface better match results from first-principles calculations with density-functional theory (DFT). We tested the ability of the potential to reproduce the phonon dispersion and heat capacity of bulk solid GaAs by comparing it to experiment and the overall agreement is good. In the modified potential, the GaAs(001) β2(2 × 4) reconstruction is favored under As-rich growth conditions in agreement with DFT calculations. Additionally, the binding energies and diffusion barriers for a Ga adatom on the β2(2 × 4) reconstruction generally match results from DFT calculations. These studies indicate that the potential is suitable for investigating aspects of GaAs(001) homoepitaxy
The impact of point mutations in the human androgen receptor : classification of mutations on the basis of transcriptional activity
Peer reviewedPublisher PD
Manufacturing of metallic micro components using hybrid soft lithography and micro-electrical discharge machining
Evidence for at Belle
We search for the decay with , where the is not measured, using a data
sample corresponding to an integrated luminosity of 711 which
contains 772 pairs, collected around the
(4S) resonance with the Belle detector at the KEKB asymmetric-energy
collider. We measure for the first time the branching fraction to be with a significance of . We simultaneously measure
the branching fraction for the related channel
with much improved precision.Comment: 7 pages, 5 figures, 4 tables. To be submitted to PR
Neurological manifestations of SARS-CoV-2 infection in hospitalised children and adolescents in the UK: a prospective national cohort study
BACKGROUND: The spectrum of neurological and psychiatric complications associated with paediatric SARS-CoV-2 infection is poorly understood. We aimed to analyse the range and prevalence of these complications in hospitalised children and adolescents. METHODS: We did a prospective national cohort study in the UK using an online network of secure rapid-response notification portals established by the CoroNerve study group. Paediatric neurologists were invited to notify any children and adolescents (age <18 years) admitted to hospital with neurological or psychiatric disorders in whom they considered SARS-CoV-2 infection to be relevant to the presentation. Patients were excluded if they did not have a neurological consultation or neurological investigations or both, or did not meet the definition for confirmed SARS-CoV-2 infection (a positive PCR of respiratory or spinal fluid samples, serology for anti-SARS-CoV-2 IgG, or both), or the Royal College of Paediatrics and Child Health criteria for paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS). Individuals were classified as having either a primary neurological disorder associated with COVID-19 (COVID-19 neurology group) or PIMS-TS with neurological features (PIMS-TS neurology group). The denominator of all hospitalised children and adolescents with COVID-19 was collated from National Health Service England data. FINDINGS: Between April 2, 2020, and Feb 1, 2021, 52 cases were identified; in England, there were 51 cases among 1334 children and adolescents hospitalised with COVID-19, giving an estimated prevalence of 3·8 (95% CI 2·9-5·0) cases per 100 paediatric patients. 22 (42%) patients were female and 30 (58%) were male; the median age was 9 years (range 1-17). 36 (69%) patients were Black or Asian, 16 (31%) were White. 27 (52%) of 52 patients were classified into the COVID-19 neurology group and 25 (48%) were classified into the PIMS-TS neurology group. In the COVID-19 neurology group, diagnoses included status epilepticus (n=7), encephalitis (n=5), Guillain-Barré syndrome (n=5), acute demyelinating syndrome (n=3), chorea (n=2), psychosis (n=2), isolated encephalopathy (n=2), and transient ischaemic attack (n=1). The PIMS-TS neurology group more often had multiple features, which included encephalopathy (n=22 [88%]), peripheral nervous system involvement (n=10 [40%]), behavioural change (n=9 [36%]), and hallucinations at presentation (n=6 [24%]). Recognised neuroimmune disorders were more common in the COVID-19 neurology group than in the PIMS-TS neurology group (13 [48%] of 27 patients vs 1 [<1%] of 25 patients, p=0·0003). Compared with the COVID-19 neurology group, more patients in the PIMS-TS neurology group were admitted to intensive care (20 [80%] of 25 patients vs six [22%] of 27 patients, p=0·0001) and received immunomodulatory treatment (22 [88%] patients vs 12 [44%] patients, p=0·045). 17 (33%) patients (10 [37%] in the COVID-19 neurology group and 7 [28%] in the PIMS-TS neurology group) were discharged with disability; one (2%) died (who had stroke, in the PIMS-TS neurology group). INTERPRETATION: This study identified key differences between those with a primary neurological disorder versus those with PIMS-TS. Compared with patients with a primary neurological disorder, more patients with PIMS-TS needed intensive care, but outcomes were similar overall. Further studies should investigate underlying mechanisms for neurological involvement in COVID-19 and the longer-term outcomes. FUNDING: UK Research and Innovation, Medical Research Council, Wellcome Trust, National Institute for Health Research
First Simultaneous Determination of Inclusive and Exclusive
The first simultaneous determination of the absolute value of the
Cabibbo-Kobayashi-Maskawa matrix element using inclusive and exclusive
decays is performed with the full Belle data set at the
resonance, corresponding to an integrated luminosity of 711 fb. We
analyze collision events in which one meson is fully reconstructed in
hadronic modes. This allows for the reconstruction of the hadronic system
of the semileptonic decay. We separate exclusive
decays from other inclusive and backgrounds with a two-dimensional fit, that
utilizes the number of charged pions in the system and the four-momentum
transfer between the and system. Combining our measurement with
information from lattice QCD and QCD calculations of the inclusive partial rate
as well as external experimental information on the shape of the form factor, we determine
and , respectively, with the uncertainties
being the statistical error, systematic errors, and theory errors. The ratio of
is compatible with unity.Comment: 7 pages, 3 captioned figures, including supplemental materia
Measurement of the cross section in the energy range from to GeV using inclusive and production
We report the first measurement of the inclusive and cross sections in the
energy range from to . Based on these results, we determine
and
in the same energy range. We measure the fraction of events at
to be . We determine also
the ratio of the inclusive branching fractions .
The results are obtained using the data collected with the Belle detector at
the KEKB asymmetric-energy collider
First measurement of the Michel parameter in the decay at Belle
We report the first measurement of the Michel parameter in the
decay with a new method proposed just
recently. The measurement is based on the reconstruction of the
events with subsequent muon
decay-in-flight in the Belle central drift chamber. The analyzed data sample of
collected by the Belle detector corresponds to
approximately pairs. We measure
, which is in
agreement with the Standard Model prediction of . Statistical
uncertainty dominates in this study, being a limiting factor, while systematic
uncertainty is well under control. Our analysis proved the practicability of
this promising method and its prospects for further precise measurement in
future experiments.Comment: 6 pages, 4 figures, submitted to Phys. Rev. Let
Study of the lineshape of using decays to
We present a study of the lineshape in the decay using a data sample of
pairs collected at the resonance with the Belle
detector at the KEKB asymmetric-energy collider. The peak near the
threshold in the invariant mass spectrum is fitted
using a relativistic Breit-Wigner lineshape. We determine the mass and width
parameters to be and , respectively. The branching fraction is found to be
. The signal from decays is observed for the first
time with significance, and the ratio of branching fractions
between charged and neutral decays is measured to be . The peak is also studied using a Flatt\'{e}
lineshape. We determine the lower limit on the coupling
constant to be at 95% credibility in the parameter region where the
ratio of to the mass difference from the threshold
is equal to , as measured by LHCb.Comment: submitted to Phys. Rev
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