Structure and lattice dynamics of the wide band gap semiconductors MgSiN2_{2} and MgGeN2_{2}

We have determined the structural and lattice dynamical properties of the orthorhombic, wide band gap semiconductors MgSiN$_{2}$ and MgGeN$_{2}$ using density functional theory. In addition, we present structural properties and Raman spectra of a MgSiN$_{2}$ powder. The structural properties and lattice dynamics of the orthorhombic systems are compared to wurtzite AlN. We find clear differences in the lattice dynamics between MgSiN$_{2}$, MgGeN$_{2}$ and AlN, for example we find that the highest phonon frequency in MgSiN$_{2}$ is about 100~cm$^{-1}$ higher than the highest frequency in AlN and that MgGeN$_{2}$ is much softer. We also provide the Born effective charge tensors and dielectric tensors of MgSiN$_{2}$, MgGeN$_{2}$ and AlN. Phonon related thermodynamic properties, such as the heat capacity and entropy, are in very good agreement with available experimental results.Comment: 9 pages, 11 figures, 6 table

Modelling the evolution of distributions : an application to major league baseball

We develop Bayesian techniques for modelling the evolution of entire distributions over time and apply them to the distribution of team performance in Major League baseball for the period 1901-2000. Such models offer insight into many key issues (e.g. competitive balance) in a way that regression-based models cannot. The models involve discretizing the distribution and then modelling the evolution of the bins over time through transition probability matrices. We allow for these matrices to vary over time and across teams. We find that, with one exception, the transition probability matrices (and, hence, competitive balance) have been remarkably constant across time and over teams. The one exception is the Yankees, who have outperformed all other teams

Just keep grazing: Parrotfish grazing and dietary selectivity in the Florida Keys

Parrotfish have indirect positive effects on corals by grazing on macroalgae that competes for substrate space with corals. Parrotfish can also have a negative impact on corals by feeding on live coral. Feeding preferences are correlated to jaw morphology in parrotfishes. This study examined the feeding selectivity for two genera of parrotfish (Scarus and Sparisoma) in the Florida Keys to determine the impacts they have on coral reefs. On 14 reefs, fish censuses, behavioral surveys and substrate composition analysis were preformed to calculate selectivity indices for the various substrate types. The indices showed that parrotfish do exhibit selective feeding. Scarus had a significantly higher preference for turf and Sparisoma had a significantly higher preference for macroalgae. These results support life history theory that Scarus are excavators and Sparisoma are grazers as predicted by their jaw morphology. This project was partially supported by the Creative Inquiry program

Ignition of thermally sensitive explosives between a contact surface and a shock

The dynamics of ignition between a contact surface and a shock wave is investigated using a one-step reaction model with Arrhenius kinetics. Both large activation energy asymptotics and high-resolution finite activation energy numerical simulations are employed. Emphasis is on comparing and contrasting the solutions with those of the ignition process between a piston and a shock, considered previously. The large activation energy asymptotic solutions are found to be qualitatively different from the piston driven shock case, in that thermal runaway first occurs ahead of the contact surface, and both forward and backward moving reaction waves emerge. These waves take the form of quasi-steady weak detonations that may later transition into strong detonation waves. For the finite activation energies considered in the numerical simulations, the results are qualitatively different to the asymptotic predictions in that no backward weak detonation wave forms, and there is only a weak dependence of the evolutionary events on the acoustic impedance of the contact surface. The above conclusions are relevant to gas phase equation of state models. However, when a large polytropic index more representative of condensed phase explosives is used, the large activation energy asymptotic and finite activation energy numerical results are found to be in quantitative agreement

Revenue divergence and competitive balance in a divisional sports league

The North American model of resource allocation in professional sports leagues is adapted for English (association) football. The theoretical relationship between revenue and competitive balance is shown to be robust with respect to changes in teams’ objectives and labour market conditions. Empirical revenue functions are reported for 1926-1999. These indicate a shift in the composition of demand favouring big-city teams and an increase in the sensitivity of revenue to performance. An analysis of match results in the FA Cup competition suggests an increase in competitive imbalance between teams at different levels of the league’s divisional hierarchy, as the theory suggests

Patient experience of lasting negative effects of psychological interventions for anxiety and depression in secondary mental health care services: a national cross-sectional study

Background Patients who undergo psychological treatment can report both negative and positive effects, but evidence of factors influencing the likelihood of negative effects is limited. Aims To identify aspects of the organisation and delivery of secondary care psychological treatment services that are associated with patient experiences of negative effects. Method Cross-sectional survey of people with anxiety and depression who ended psychological treatment delivered by 50 NHS trusts in England. Respondents were asked about how their treatment was organised and delivered and whether they experienced lasting negative effects. Results Of 662 respondents, 90 (14.1%) reported experiencing lasting negative effects. People over the age of 65 were less likely than younger respondents to report negative effects. There was an association between reporting neutral or negative effects and not being referred at what respondents considered to be the right time (OR = 1.712, 95% CI = 1.078–2.726), not receiving the right number of sessions (OR = 3.105, 95% CI = 1.934–4.987), and not discussing progress with their therapist (OR 2.063, 95% CI = 1.290–3.301). Conclusions One in seven patients who took part in this survey reported lasting negative effects from psychological treatment. Steps should be taken to prepare people for the potential for negative experiences of treatment, and progress reviewed during therapy in an effort to identify and prevent negative effects

Impact of co‐morbid personality disorder on quality of inpatient mental health services for people with anxiety and depression

Introduction Concerns have been raised about the quality of inpatient care received by patients with a diagnosis of personality disorder. Objectives The aim of this study was to examine the quality of care received by inpatients with an anxiety or depressive disorder, comparing subgroups with or without a co‐morbid personality disorder. Method We used a retrospective case‐note review of 3 795 patients admitted to inpatient psychiatric wards in England, utilizing data from the National Clinical Audit of Anxiety and Depression. Data were gathered on all acute admissions with an anxiety or depressive disorder over a 6‐month period, for a number of measures reflecting quality of care derived from national standards. Association of coexisting personality disorder with quality of care was investigated using multivariable regression analyses. Results Four hundred sixteen (11.0%) of the patients had a co‐co‐morbid diagnosis of personality disorder. Patients with personality disorder were less likely to have been asked about prior responses to treatment in their initial assessment (odds ratio (OR) = 0.67, 95% confidence interval (CI) 0.50 to 0.89, p = 0.007). They were less likely to receive adequate notice in advance of their discharge (OR = 0.87, 95% CI 0.65 to 0.98, p = 0.046). They were more likely to be prescribed medication at the point of discharge (OR = 1.52, 95% CI 1.02 to 2.09, p = 0.012) and less likely to have been provided with information about the medicines they were taking (OR = 0.86, 95% CI 0.69 to 0.94, p = 0.048). In addition, the carers of patients with co‐morbid personality disorder were less likely to have been provided with information about available support services (OR = 0.73, 95% CI 0.51 to 0.93, p = 0.045). Conclusion We found evidence of poorer quality of care for patients with co‐morbid personality disorder who were admitted to psychiatric hospital for treatment of anxiety or depressive disorders, highlighting the need for improved clinical care in this patient group

Positive allosteric modulation as a potential therapeutic strategy in anti-NMDA receptor encephalitis

N-methyl-d-aspartate receptors (NMDARs) are ionotropic glutamate receptors important for synaptic plasticity, memory, and neuropsychiatric health. NMDAR hypofunction contributes to multiple disorders, including anti-NMDAR encephalitis (NMDARE), an autoimmune disease of the CNS associated with GluN1 antibody-mediated NMDAR internalization. Here we characterize the functional/pharmacological consequences of exposure to CSF from female human NMDARE patients on NMDAR function, and we characterize the effects of intervention with recently described positive allosteric modulators (PAMs) of NMDARs. Incubation (48 h) of rat hippocampal neurons of both sexes in confirmed NMDARE patient CSF, but not control CSF, attenuated NMDA-induced current. Residual NMDAR function was characterized by lack of change in channel open probability, indiscriminate loss of synaptic and extrasynaptic NMDARs, and indiscriminate loss of GluN2B-containing and GluN2B-lacking NMDARs. NMDARs tagged with N-terminal pHluorin fluorescence demonstrated loss of surface receptors. Thus, function of residual NMDARs following CSF exposure was indistinguishable from baseline, and deficits appear wholly accounted for by receptor loss. Coapplication of CSF and PAMs of NMDARs (SGE-301 or SGE-550, oxysterol-mimetic) for 24 h restored NMDAR function following 24 h incubation in patient CSF. Curiously, restoration of NMDAR function was observed despite washout of PAMs before electrophysiological recordings. Subsequent experiments suggested that residual allosteric potentiation of NMDAR function explained the persistent rescue. Further studies of the pathogenesis of NMDARE and intervention with PAMs may inform new treatments for NMDARE and other disorders associated with NMDAR hypofunction.SIGNIFICANCE STATEMENTAnti-N-methyl-d-aspartate receptor encephalitis (NMDARE) is increasingly recognized as an important cause of sudden-onset psychosis and other neuropsychiatric symptoms. Current treatment leaves unmet medical need. Here we demonstrate cellular evidence that newly identified positive allosteric modulators of NMDAR function may be a viable therapeutic strategy.</jats:p