European Starlings (Sturnus Vulgaris) : Avian Model and Monitor of Contaminant and Remedial Effects at Crab Orchard National Wildlife Refuge

WMRC Project #94-12

Development and Characterization of a Fast Neutron Imaging Telescope (FNIT) for 1--20 MeV Neutrons From the Sun and Nuclear Material

We discuss the development and complete characterization of a double scatter telescope for 1--20 MeV neutrons intended for applications in solar physics and nuclear security. In high-energy solar physics, detecting the presence of low energy accelerated ions in the low corona is recognized as an important goal. The surest indication of the acceleration of these particles is the detection of low energy (\u3c10 MeV) neutrons. These measurements can only be made in the inner heliosphere due to the finite neutron lifetime and flux divergence as they leave the Sun. Additionally, the field of nuclear security has interest in an instrument that can detect, measure, and locate sources of (\u3c10 MeV) neutrons from nuclear material. Materials of interest, namely uranium and transuranics, emit neutrons via spontaneous or induced fission. Unlike other neutral emission from nuclear material, (e.g. gamma rays), copious and penetrating neutron emission is unique to fissionable material. The FNIT instrument was carefully tailored for both applications with a low energy threshold. A double scatter instrument allows for background rejection techniques to obtain increased sensitivity. A small, modular prototype instrument was constructed at UNH with laboratory calibration completed to tune the pulse height and shape, threshold, and time-of-flight for neutron measurements. Quasi-monoenergetic neutron beams calibrated the prototype over the full energy range and fission neutrons were used to test the response and performance of the instrument. Simulations characterized the instrument energy response and were used to generate response matrices for data inversion. We used zeroth-order Tikhonov regularization de-convolution algorithms to obtain the true neutron source spectrum for a given regularization (smoothing) parameter, lambda. Independent of the binning strategy, lambda is of order 10-6. We find that lambda +/- sigma results in a 2% error in total neutron counts; an error within +/-5-sigma results in a variation of ≤ 30% in total neutron counts. Double scatter imaging, adopted from gamma-ray telescopes, demonstrate source location identification can be obtained. We apply laboratory and simulation information to obtain performance estimates of future instruments near the Sun and in the field

A discrete-time Markov modulated queuing system with batched arrivals

This paper examines a discrete-time queuing system with applications to telecommunications traffic. The arrival process is a particular Markov modulated process which belongs to the class of discrete batched Markovian arrival processes. The server process is a single server deterministic queue. A closed form exact solution is given for the expected queue length and delay. A simple system of equations is given for the probability of the queue exceeding a given length.Comment: to appear Performance Evaluatio

A gastrointestinal stromal tumour presenting incidentally with haemorrhage and perforation associated with a Meckel's diverticulum: a case report

<p>Abstract</p> <p>Introduction</p> <p>This is the first reported case of perforation and haemorrhage of a Meckel's diverticulum leading to the incidental finding of a gastrointestinal stromal tumour within the diverticulum. Meckel's diverticulum is the most common congenital abnormality of the gastrointestinal tract, however, when symptomatic, it is often misdiagnosed at presentation. Common complications presenting in adults include bleeding, obstruction, diverticulitis and perforation. Tumours within a Meckel's diverticulum are a rare but recognised complication. We discuss the management of a gastrointestinal tumour within the diverticulum.</p> <p>Case presentation</p> <p>A 59-year-old Caucasian man presented with acute right iliac fossa pain with localized peritonism. At surgery, he was found to have a perforated and haemorrhagic Meckel's diverticulum, associated with a gastrointestinal stromal tumour within the apex of the diverticulum. The absence of necrosis and a low mitotic rate indicated primary resection with subsequent computed tomography surveillance to be the most appropriate management strategy.</p> <p>Conclusion</p> <p>We report a unique triad of complications associated with the presentation of a Meckel's diverticulum. This article reviews this common congenital abnormality and discusses the management of a gastrointestinal tumour. Meckel's diverticulum will mimic other intra-abdominal pathologies in presentation and should therefore often be considered as a differential diagnosis.</p

Real-time Likelihood Methods for Improved Gamma-ray Transient Detection and Localization

We present a maximum likelihood (ML) algorithm that is fast enough to detect gamma-ray transients in real time on low-performance processors often used for space applications. We validate the routine with simulations and find that, relative to algorithms based on excess counts, the ML method is nearly twice as sensitive, allowing detection of 240-280% more short gamma-ray bursts. We characterize a reference implementation of the code, estimating its computational complexity and benchmarking it on a range of processors. We exercise the reference implementation on archival data from the Fermi Gamma-ray Burst Monitor (GBM), verifying the sensitivity improvements. In particular, we show that the ML algorithm would have detected GRB 170817A even if it had been nearly four times fainter. We present an ad hoc but effective scheme for discriminating transients associated with background variations. We show that the on-board localizations generated by ML are accurate, but that refined off-line localizations require a detector response matrix with about ten times finer resolution than is current practice. Increasing the resolution of the GBM response matrix could substantially reduce the few-degree systematic uncertainty observed in the localizations of bright bursts.Comment: 18 pages, 11 figure

Fitness to practise sanctions in UK doctors are predicted by poor performance at MRCGP and MRCP(UK) assessments: data linkage study.

BACKGROUND: The predictive validity of postgraduate examinations, such as MRCGP and MRCP(UK) in the UK, is hard to assess, particularly for clinically relevant outcomes. The sanctions imposed on doctors by the UK's General Medical Council (GMC), including erasure from the Medical Register, are indicators of serious problems with fitness to practise (FtP) that threaten patient safety or wellbeing. This data linkage study combined data on GMC sanctions with data on postgraduate examination performance. METHODS: Examination results were obtained for UK registered doctors taking the MRCGP Applied Knowledge Test (AKT; n = 27,561) or Clinical Skills Assessment (CSA; n = 17,365) at first attempt between 2010 and 2016 or taking MRCP(UK) Part 1 (MCQ; n = 37,358), Part 2 (MCQ; n = 28,285) or Practical Assessment of Clinical Examination Skills (PACES; n = 27,040) at first attempt between 2001 and 2016. Exam data were linked with GMC actions on a doctor's registration from September 2008 to January 2017, sanctions including Erasure, Suspension, Conditions on Practice, Undertakings or Warnings (ESCUW). Examination results were only considered at first attempts. Multiple logistic regression assessed the odds ratio for ESCUW in relation to examination results. Multiple imputation was used for structurally missing values. RESULTS: Doctors sanctioned by the GMC performed substantially less well on MRCGP and MRCP(UK), with a mean Cohen's d across the five exams of - 0.68. Doctors on the 2.5th percentile of exam performance were about 12 times more likely to have FtP problems than those on the 97.5th percentile. Knowledge assessments and clinical assessments were independent predictors of future sanctions, with clinical assessments predicting ESCUW significantly better. The log odds of an FtP sanction were linearly related to examination marks over the entire range of performance, additional performance increments lowering the risk of FtP sanctions at all performance levels. CONCLUSIONS: MRCGP and MRCP(UK) performance are valid predictors of professionally important outcomes that transcend simple knowledge or skills and the GMC puts under the headings of conduct and trust. Postgraduate examinations may predict FtP sanctions because the psychological processes involved in successfully studying, understanding and practising medicine at a high level share similar mechanisms to those underlying conduct and trust

Delivering word retrieval therapies for people with aphasia in a virtual communication environment

Background: Delivering therapy remotely, via digital technology, can enhance provision for people with aphasia. EVA Park is a multi-user virtual island that can be used for such delivery. The first EVA Park study showed that daily language stimulation delivered via the platform improved functional communication and was positively received by users (Marshall et al, 2016; Amaya et al, 2018). This paper reports two single case studies, evaluating its capacity to deliver targeted language interventions. The first employed therapy for noun retrieval, using cued picture naming and modified Sematic Feature Analysis. The second employed modified Verb Network Strengthening Treatment (VNeST). Aims: This study aimed to determine if treatment delivery was feasible in EVA Park, as assessed by participant compliance, treatment fidelity and participants’ views. It explored the impact of the therapies on treated and untreated word production, connected speech and functional communication. Methods & Procedures: Two participants with aphasia each received 20 sessions of individual therapy in EVA Park, delivered over 5 weeks. Feasibility was assessed by measuring compliance with the therapy regime, recording and checking the fidelity of 20% of treatment sessions, and using post therapy interviews to explore participant views. Treatment outcomes were evaluated via repeated measures single case designs, in which assessments were administered twice before therapy, immediately post therapy and five weeks later. Outcome measures included Object Picture Naming (study 1), Sentence Elicitation Pictures (study 2), Naming 84 items from the Object and Action Naming Battery (study 2), Narrative Production (Study 2), the Northwestern Assessment of Verb and Sentences: Argument Structure Production Test (Study 2) and Communication Activities of Daily Living – 2 (Study 1 & 2). Outcomes & Results: Feasibility results were excellent. Both participants were fully compliant with the therapy regime. There was at least 90% fidelity with the treatment protocols and participant views were positive. Outcomes varied across the studies. The noun therapy significantly improved the naming of treated words, with good maintenance. Lexical gains were less evident on the Sentence Elicitation Pictures used in the VNeST study. Neither study demonstrated generalisation to untreated words, connected speech or functional communication. Conclusions: Two treatment approaches, designed for face to face delivery, could be delivered remotely in EVA Park. Outcomes for the noun treatment were comparable to previous evaluations. Comparisons with previous research were more challenging for VNeST, owing to differences in methodology. Further evaluations of other treatment approaches are warranted