2,284 research outputs found
Elastic Nd scattering at intermediate energies as a tool for probing the short-range deuteron structure
A calculation of the deuteron polarization observables , ,
, and the differential cross-section for elastic
nucleon-deuteron scattering at incident deuteron energies 270 and 880 MeV in
lab is presented. A comparison of the calculations with two different deuteron
wave-functions derived from the Bonn-CD -potential model and the dressed
bag quark model is carried out. A model-independent approach, based on an
optical potential framework, is used in which a nucleon-nucleon -matrix is
assumed to be local and taken on the energy shell, but still depends on the
internal nucleon momentum in a deuteron.Comment: 15 pages, 4 figure
Intermediate Tail Dependence: A Review and Some New Results
The concept of intermediate tail dependence is useful if one wants to
quantify the degree of positive dependence in the tails when there is no strong
evidence of presence of the usual tail dependence. We first review existing
studies on intermediate tail dependence, and then we report new results to
supplement the review. Intermediate tail dependence for elliptical, extreme
value and Archimedean copulas are reviewed and further studied, respectively.
For Archimedean copulas, we not only consider the frailty model but also the
recently studied scale mixture model; for the latter, conditions leading to
upper intermediate tail dependence are presented, and it provides a useful way
to simulate copulas with desirable intermediate tail dependence structures.Comment: 25 pages, 1 figur
Implications of Pseudospin Symmetry on Relativistic Magnetic Properties and Gamow - Teller Transitions in Nuclei
Recently it has been shown that pseudospin symmetry has its origins in a
relativistic symmetry of the Dirac Hamiltonian. Using this symmetry we relate
single - nucleon relativistic magnetic moments of states in a pseudospin
doublet to the relativistic magnetic dipole transitions between the states in
the doublet, and we relate single - nucleon relativistic Gamow - Teller
transitions within states in the doublet. We apply these relationships to the
Gamow - Teller transitions from to its mirror nucleus .Comment: 17 pages, 2 figures, to be published in PRC. Slightly revised text
with one reference adde
Protocol for a feasibility randomised controlled trial of targeted oxygen therapy in mechanically ventilated critically ill patients
IntroductionOxygen is the most commonly administered drug to mechanically ventilated critically ill adults, yet little is known about the optimum oxygen saturation (SpO2) target for these patients; the current standard of care is an SpO2of 96% or above. Small pilot studies have demonstrated that permissive hypoxaemia (aiming for a lower SpO2than normal by using a lower fractional inspired oxygen concentration (FIO2)) can be achieved in the critically ill and appears to be safe. This approach has not been evaluated in a National Health Service setting. It is possible that permissive hypoxaemia may be beneficial to critically ill patients thus it requires robust evaluation.Methods and analysisTargeted OXygen therapY in Critical illness (TOXYC) is a feasibility randomised controlled trial (RCT) to evaluate whether recruiting patients to a study of permissive hypoxaemia is possible in the UK. It will also investigate biological mechanisms that may underlie the links between oxygenation and patient outcomes. Mechanically ventilated patients with respiratory failure will be recruited from critical care units at two sites and randomised (1:1 ratio) to an SpO2target of either 88%–92% or ≥96% while intubated with an endotracheal tube. Clinical teams can adjust FIO2and ventilator settings as they wish to achieve these targets. Clinical information will be collected before, during and after the intervention and blood samples taken to measure markers of systemic oxidative stress. The primary outcome of this study is feasibility, which will be assessed by recruitment rate, protocol adherence and withdrawal rates. Secondary outcomes will include a comparison of standard critical care outcome measures between the two intervention groups, and the measurement of biomarkers of systemic oxidative stress. The results will be used to calculate a sample size, likely number of sites and overall length of time required for a subsequent large multicentre RCT.Ethics and disseminationThis study was approved by the London - Harrow Research Ethics Committee on 2 November 2017 (REC Reference 17/LO/1334) and received HRA approval on 13 November 2017. Results from this study will be disseminated in peer-reviewed journals, at medical and scientific meetings, in the NIHR Journals Library and patient information websites.Trial registration numberNCT03287466; Pre-results.</jats:sec
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Extremes on the discounted aggregate claims in a time dependent risk model
This paper presents an extension of the classical compound Poisson risk model for which the inter-claim time and the forthcoming claim amount are no longer independent random variables (rv's). Asymptotic tail probabilities for the discounted aggregate claims are presented when the force of interest is constant and the claim amounts are heavy tail distributed rv's. Furthermore, we derive asymptotic finite time ruin probabilities, as well as asymptotic approximations for some common risk measures associated with the discounted aggregate claims. A simulation study is performed in order to validate the results obtained in the free interest risk model
Antipsychotic Use in Pregnancy: Patient Mental Health Challenges, Teratogenicity, Pregnancy Complications, and Postnatal Risks
Pregnant women constitute a vulnerable population, with 25.3% of pregnant women classified as suffering from a psychiatric disorder. Since childbearing age typically aligns with the onset of mental health disorders, it is of utmost importance to consider the effects that antipsychotic drugs have on pregnant women and their developing fetus. However, the induction of pharmacological treatment during pregnancy may pose significant risks to the developing fetus. Antipsychotics are typically introduced when the nonpharmacologic approaches fail to produce desired effects or when the risks outweigh the benefits from continuing without treatment or the risks from exposing the fetus to medication. Early studies of pregnant women with schizophrenia showed an increase in perinatal malformations and deaths among their newborns. Similar to schizophrenia, women with bipolar disorder have an increased risk of relapse in antepartum and postpartum periods. It is known that antipsychotic medications can readily cross the placenta, and exposure to antipsychotic medication during pregnancy is associated with potential teratogenicity. Potential risks associated with antipsychotic use in pregnant women include congenital abnormalities, preterm birth, and metabolic disturbance, which could potentially lead to abnormal fetal growth. The complex decision-making process for treating psychosis in pregnant women must evaluate the risks and benefits of antipsychotic drugs
Role of heavy-meson exchange in pion production near threshold
Recent calculations of -wave pion production have severely underestimated
the accurately known \ total cross section near
threshold. In these calculations, only the single-nucleon axial-charge operator
is considered. We have calculated, in addition to the one-body term, the
two-body contributions to this reaction that arise from the exchange of mesons.
We find that the inclusion of the scalar -meson exchange current (and
lesser contributions from other mesons) increases the cross section by about a
factor of five, and leads to excellent agreement with the data. The results are
neither very sensitive to changes in the distorting potential that generates
the wave function, nor to different choices for the meson-nucleon form
factors. We argue that \ data provide direct
experimental evidence for meson-exchange contributions to the axial current.Comment: 28 Pages, IU-NTC #93-0
Mother–infant interaction in schizophrenia:Transmitting risk or resilience? A systematic review of the literature
Purpose:
The parent–infant relationship is an important context for identifying very early risk and resilience factors and targets for the development of preventative interventions. The aim of this study was to systematically review studies investigating the early caregiver–infant relationship and attachment in offspring of parents with schizophrenia.
Methods:
We searched computerized databases for relevant articles investigating the relationship between early caregiver–infant relationship and outcomes for offspring of a caregiver with a diagnosis of schizophrenia. Studies were assessed for risk of bias.
Results:
We identified 27 studies derived from 10 cohorts, comprising 208 women diagnosed with schizophrenia, 71 with other psychoses, 203 women with depression, 59 women with mania/bipolar disorder, 40 with personality disorder, 8 with unspecified mental disorders and 119 non-psychiatric controls. There was some evidence to support disturbances in maternal behaviour amongst those with a diagnosis of schizophrenia and there was more limited evidence of disturbances in infant behaviour and mutuality of interaction.
Conclusions:
Further research should investigate both sources of resilience and risk in the development of offspring of parents with a diagnosis of schizophrenia and psychosis. Given the lack of specificity observed in this review, these studies should also include maternal affective disorders including depressive and bipolar disorders
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