15,375 research outputs found

    Patterns of Sponge Abundance Across a Gradient of Habitat Quality in the Wakatobi Marine National Park, Indonesia

    Get PDF
    Sponges are important components of reef communities worldwide, fulfilling a number of important functional roles. Habitat degradation caused by the loss of hard corals has the potential to cause increases in sponge abundance and percentage cover as they gain access to resources such as space and food. In this study we compared sponge densities and percentage cover at sites with varying hard coral cover in the Wakatobi Marine National Park, Indonesia (WMNP). We found significant differences in sponge densities at the study sites but no significant difference in sponge densities on different surface angles. Unexpectedly, we also found a weak positive correlation between coral cover and sponge density. This indicates that spatial competition is unlikely to be the most important factor determining sponge abundance in the WMNP. In contrast to sponge density data, we found that sponge percentage cover and hard coral cover were weakly negatively correlated, but found no significant difference in sponge percentage cover between the study sites. Finally, multivariate analysis of the benthic communities at the study sites indicated that while sites with higher coral cover were characterised by coral (proportionally), lower coral cover sites were characterised by algae and sponges. This suggests that although there was no significant difference in sponge percentage cover between the study sites conditions that led to the loss of hard coral at lower quality sites mean that these sites are characterised by sponges and algae rather than by any other groups of benthic organisms

    Measuring attitude towards Buddhism and Sikhism : internal consistency reliability for two new instruments

    Get PDF
    This paper describes and discusses the development and empirical properties of two new 24-item scales – one measuring attitude toward Buddhism and the other measuring attitude toward Sikhism. The scale is designed to facilitate inter-faith comparisons within the psychology of religion alongside the well-established Francis Scale of Attitude toward Christianity. Data were obtained from a multi-religious sample of 369 school pupils aged between 13 and 15 in London. Application of the two scales demonstrated that adolescents had a more positive attitude to Buddhism than Sikhism. The findings confirm the reliability of the scales and commend them for further use

    The CCD and readout electronics for the OMC instrument on Integral

    Get PDF
    The Optical Monitoring Camera (OMC) on ESA's Integral gamma-ray astronomy satellite is devoted to optical wavelength observations simultaneously covering the same field-of-view as the gamma-ray and X-ray instruments. The OMC consists of a refracting telescope with a CCD as the imaging device in the focal plane. Here we describe the CCD and its associated readout electronics, in particular pointing out features of interest to users of the OMC instrument and its data

    A compact spike-timing-dependent-plasticity circuit for floating gate weight implementation

    Get PDF
    AbstractSpike timing dependent plasticity (STDP) forms the basis of learning within neural networks. STDP allows for the modification of synaptic weights based upon the relative timing of pre- and post-synaptic spikes. A compact circuit is presented which can implement STDP, including the critical plasticity window, to determine synaptic modification. A physical model to predict the time window for plasticity to occur is formulated and the effects of process variations on the window is analyzed. The STDP circuit is implemented using two dedicated circuit blocks, one for potentiation and one for depression where each block consists of 4 transistors and a polysilicon capacitor. SpectreS simulations of the back-annotated layout of the circuit and experimental results indicate that STDP with biologically plausible critical timing windows over the range from 10”s to 100ms can be implemented. Also a floating gate weight storage capability, with drive circuits, is presented and a detailed analysis correlating weights changes with charging time is given

    Developing doctors: what are the attitudes and perceptions of year 1 and 2 medical students towards a new integrated formative objective structured clinical examination?

    Get PDF
    BACKGROUND: Objective Structured Clinical Examination (OSCE) is a core component of undergraduate medical student assessment. With increased emphasis on integrated programmes, more courses include OSCEs in the traditionally 'preclinical' years. The acceptability and impact of such assessment methods at this stage of training is unknown. METHODS: In 2013 and 2014 University College London Medical School piloted a formative, integrated OSCE in years 1 and 2 of the undergraduate medical degree programme. This study with a sequential exploratory design aimed to explore the acceptability and impact of such an OSCE in the early years of medical school. 1280 students completed the OSCE and were invited to complete a questionnaire exploring their views of the OSCE (response rate 96.6 %). Four focus groups, each with five or six participants (22 in total) were subsequently held to further explore themes. Data was independently transcribed and coded using thematic analysis. RESULTS: Students were strongly in favour of the introduction of an OSCE in addition to existing assessments. Six overarching themes were identified: application of knowledge and skills; OSCE as an experience; OSCE as a process; a learning curve; becoming a doctor; and creating an effective OSCE. CONCLUSIONS: Results strongly support the role of OSCE early in the medical course with many benefits reported. An OSCE at this stage aligns with the vision of integrated medical education which includes early patient contact and introduction of clinical and professional skills. It also fosters feelings of responsibility and professional identity amongst students

    Mass-loss rates for 21 Wolf–Rayet stars

    Get PDF
    Mass-loss rates have been derived for 21 WR stars encompassing most subtypes in the WN and WC sequences, from measurements of their infrared free–free fluxes. The resultant mass-loss rates show a range of only a factor of 4. WC stars generally have larger mass-loss rates than WN stars, the mean rates being M˙(WC)=4.1×10−5M⊙yr−1 and M˙(WN)=2.7×10−5M⊙yr−1⁠. Optical and ultraviolet data have been used to estimate bolometric luminosities for a range of WR spectral types, and it is shown that the derived mass loss rates are too large to be powered by radiation pressure. The total kinetic energy injected into the interstellar medium through mass loss during the WR phase of a massive star is estimated to be 7 × 1050 erg, comparable to that of a supernova event

    Inherited polyglutamine spinocerebellar ataxias in South Africa

    Get PDF
    Objective. To determine the frequency and distribution ofpolyglutamine spinocerebellar ataxias (SCAs) from referrals over a24-year period to the National Health Laboratory Service (NHLS)in South Africa (SA).Methods. Paper-based clinical reports in the University ofCape Town laboratory and the NHLS electronic patient recorddatabase spanning a 24-year period were mined for informationregarding the molecular diagnosis, ethnicity and CAG repeatlength for individuals referred for molecular genetic testing for thepolyglutamine SCAs.Results. SCA1 and 7 are the most frequent types of polyglutamineSCA in the SA patient population, followed by SCA2, 3 and 6.SCA1 is the most common type in the coloured, white and Indianpopulations, whereas the majority of indigenous black Africanpatients are affected with SCA7 and 2. Of individuals tested, 22%were found to be positive for one of the polyglutamine SCAs.Conclusion. Although trends in the frequency and distributionof the polyglutamine SCAs in SA have not changed significantlysince our previous study in 2003, they differ remarkably from thosereported elsewhere, and reflect the unique genetic and demographicbackground of SA. The provision of accurate and complete patientinformation and family history is crucial to the diagnostic process,to enable comprehensive epidemiological studies and assist indeveloping therapeutic and patient management strategies

    Breakthrough Seizures - Further analysis of the Standard versus New Antiepileptic Drugs (SANAD) study

    Get PDF
    Objectives To develop prognostic models for risk of a breakthrough seizure, risk of seizure recurrence after a breakthrough seizure, and likelihood of achieving 12-month remission following a breakthrough seizure. A breakthrough seizure is one that occurs following at least 12 months remission whilst on treatment. Methods We analysed data from the SANAD study. This long-term randomised trial compared treatments for participants with newly diagnosed epilepsy. Multivariable Cox models investigated how clinical factors affect the probability of each outcome. Best fitting multivariable models were produced with variable reduction by Akaike’s Information Criterion. Risks associated with combinations of risk factors were calculated from each multivariable model. Results Significant factors in the multivariable model for risk of a breakthrough seizure following 12-month remission were number of tonic-clonic seizures by achievement of 12-month remission, time taken to achieve 12-month remission, and neurological insult. Significant factors in the model for risk of seizure recurrence following a breakthrough seizure were total number of drugs attempted to achieve 12-month remission, time to achieve 12-month remission prior to breakthrough seizure, and breakthrough seizure treatment decision. Significant factors in the model for likelihood of achieving 12-month remission after a breakthrough seizure were gender, age at breakthrough seizure, time to achieve 12-month remission prior to breakthrough, and breakthrough seizure treatment decision. Conclusions This is the first analysis to consider risk of a breakthrough seizure and subsequent outcomes. The described models can be used to identify people most likely to have a breakthrough seizure, a seizure recurrence following a breakthrough seizure, and to achieve 12-month remission following a breakthrough seizure. The results suggest that focussing on achieving 12-month remission swiftly represents the best therapeutic aim to reduce the risk of a breakthrough seizure and subsequent negative outcomes. This will aid individual patient risk stratification and the design of future epilepsy trials

    Neutrino Mass, Sneutrino Dark Matter and Signals of Lepton Flavor Violation in the MRSSM

    Full text link
    We study the phenomenology of mixed-sneutrino dark matter in the Minimal R-Symmetric Supersymmetric Standard Model (MRSSM). Mixed sneutrinos fit naturally within the MRSSM, as the smallness (or absence) of neutrino Yukawa couplings singles out sneutrino A-terms as the only ones not automatically forbidden by R-symmetry. We perform a study of randomly generated sneutrino mass matrices and find that (i) the measured value of ΩDM\Omega_{DM} is well within the range of typical values obtained for the relic abundance of the lightest sneutrino, (ii) with small lepton-number-violating mass terms mnn2n~n~m_{nn}^{2} {\tilde n} {\tilde n} for the right-handed sneutrinos, random matrices satisfying the ΩDM\Omega_{DM} constraint have a decent probability of satisfying direct detection constraints, and much of the remaining parameter space will be probed by upcoming experiments, (iii) the mnn2n~n~m_{nn}^{2} {\tilde n} {\tilde n} terms radiatively generate appropriately small Majorana neutrino masses, with neutrino oscillation data favoring a mostly sterile lightest sneutrino with a dominantly mu/tau-flavored active component, and (iv) a sneutrino LSP with a significant mu component can lead to striking signals of e-mu flavor violation in dilepton invariant-mass distributions at the LHC.Comment: Revised collider analysis in Sec. 5 after fixing error in particle spectrum, References adde
    • 

    corecore