The Locus Algorithm III: A Grid Computing system to generate catalogues of optimised pointings for Differential Photometry

This paper discusses the hardware and software components of the Grid Computing system used to implement the Locus Algorithm to identify optimum pointings for differential photometry of 61,662,376 stars and 23,799 quasars. The scale of the data, together with initial operational assessments demanded a High Performance Computing (HPC) system to complete the data analysis. Grid computing was chosen as the HPC solution as the optimum choice available within this project. The physical and logical structure of the National Grid computing Infrastructure informed the approach that was taken. That approach was one of layered separation of the different project components to enable maximum flexibility and extensibility

The Locus Algorithm IV: Performance metrics of a grid computing system used to create catalogues of optimised pointings

This paper discusses the requirements for and performance metrics of the the Grid Computing system used to implement the Locus Algorithm to identify optimum pointings for differential photometry of 61,662,376 stars and 23,779 quasars. Initial operational tests indicated a need for a software system to analyse the data and a High Performance Computing system to run that software in a scalable manner. Practical assessments of the performance of the software in a serial computing environment were used to provide a benchmark against which the performance metrics of the HPC solution could be compared, as well as to indicate any bottlenecks in performance. These performance metrics indicated a distinct split in the performance dictated more by differences in the input data than by differences in the design of the systems used. This indicates a need for experimental analysis of system performance, and suggests that algorithmic complexity analyses may lead to incorrect or naive conclusions, especially in systems with high data I/O overhead such as grid computing. Further, it implies that systems which reduce or eliminate this bottleneck such as in-memory processing could lead to a substantial increase in performance

Severe anaemia in sub-Saharan African children: the roles of nutrition, metabolism and the gut microbiota in recovery

Severe anaemia (Hb<5.0g/dl) affects almost 1 in 20 children in sub-Saharan Africa, and up to 1 in 4 child hospital admissions in this region (Muhe et al., 2000; Kiggundu et al., 2013). Micronutrient deficiency, malaria, infections and genetic factors contribute to its development. Severe childhood anaemia is associated with a high risk of mortality (19% within 6 months) (Phiri et al., 2008) and survivors experience long term health effects. Bacterial co-infection from gut-derived pathogenic bacteria is a frequent cause of death (Church and Maitland, 2014). Diet, altered metabolism, and the gut microbiota are thus implicated in severe anaemia, however interactions between these factors are poorly understood. The Transfusion and treatment of severe anaemia in African children study (TRACT) which assessed optimum transfusion dose, micronutrient supplementation, and prophylactic antibiotic treatment provided an opportunity to address these factors. The aim of this study was to characterise the diet of children in Eastern Uganda, and assess the impact on recovery from anaemia. It also aimed to assess whether interactions between diet and host metabolism or the gut microbiota were significantly altered in severely anaemic children, and whether changes in these were associated with recovery. A pilot study (n=19) was conducted to validate a 24-hour dietary recall method, which showed that the method had low inter-assessor variability, and high validity when compared to weighed food records. A subset (n=339) of children from the TRACT study in eastern Uganda were recruited to undergo dietary assessment and provide urine, plasma and faecal samples at admission, day 28 and day 180. A majority of children had diets which lacked diversity, reliant on a single carbohydrate-rich but micronutrient-poor food source. Food intake on admission was restricted in energy and micronutrients and was inadequate for a majority of children, but quantity and diversity increased as children recovered. Urine and plasma metabolic profiles reflected acute inadequate energy intake on admission (ketosis) and metabolic stress associated with critical illness (glycosuria and lipoprotein dysregulation), in addition to condition-specific effects including malaria-associated hyperphenylalaninaemia. These metabolic derangements resolved with treatment as children recovered. The gut microbiota of children in this study on admission lacked diversity and was dominated by potentially pathogenic Enterobacteriaceae and Enterococcus faecium. High levels of antibiotic use, in addition to low dietary diversity and dietary fibre intake contributed to reduced diversity and richness in species observed. Alterations in diet, metabolism and the gut microbiota were identified in this study in severely anaemic children, reflecting the causes and severity of this condition. Potential routes to reduce the impacts of these derangements were identified for future research.Open Acces

The PRTB Rent Index. ESRI Research Notes 2013/2/4

Data from Census 2011 show that 28.8 per cent of households rent their accommodation. The Census also shows that, between 2006 and 2011, there was a dramatic increase in the share of households in private rented accommodation. Between 2006 and 2011 the number of households in Ireland increased by 187,000 or almost 13 per cent, to 1,649,000, while the number of households renting increased by 160,000. As a result of this change in tenure pattern, according to the 2011 Census, 18.5 per cent of households were in private rented accommodation, compared with 9.9 per cent in 2006

Forming Binary Near-Earth Asteroids From Tidal Disruptions

We present simulations and observations as part of a model of the binary near-Earth asteroid population. The study of binary asteroid formation includes a series of simulations of near-Earth asteroid (NEA) tidal disruption, analyzed for bound, mutually orbiting systems. Discrete and solid particles held together only by self-gravity are employed to model a ``rubble pile'' asteroid passing Earth on a hyperbolic encounter. This is accomplished via N-body simulations, with multiple encounter and body parameters varied. We examine the relative binary production rates and the physical and orbital properties of the binaries created as a function of the parameters. We also present the overall relative likelihoods for possible physical and dynamical properties of created binaries. In order to constrain the shape and spin properties of the bodies that feed the NEA population, an observing campaign was undertaken to observe lightcurves of small Main Belt asteroids (D &lt; 5 km, SMBAs). Observations of 28 asteroids increases the overall number of SMBAs studied via lightcurves to 86. These observations allow direct comparison between NEAs and MBAs of a similar size. The shape and spin for the SMBAs are incorporated into a Monte Carlo model of a steady-state NEA population, along with the binaries created by tidal disruption simulations. Effects from tidal evolution and binary disruption from close planetary encounters are included as a means of altering or disrupting binaries. We find that with the best known progenitor (small Main Belt asteroids) shape and spin distributions, and current estimates of NEA lifetime and encounter probabilities, that tidal disruption should account for approximately 1-2% of NEAs being binaries. Given the observed estimate of an ~15% binary NEA fraction, we conclude that there are other formation mechanisms that contribute significantly to this population

The Stealth Biplane: a Proposal in Response to a Low Reynolds Number Station Keeping Mission

The Stealth Biplane is conceived and constructed to serve as a remotely piloted vehicle designed to navigate a low-level figure-eight course at a target Reynolds number of 100,000. This flight vehicle will combine the latest in lightweight radio controlled hardware in conjunction with current low Reynolds number aerodynamic research to demonstrate feasible operation in a variety of applications. These potential low Reynolds number applications include high altitude atmospheric sampling, search and rescue, and even law enforcement. Design specs and fabrication technique are discussed

Spontaneous transient outward currents arise from microdomains where BK channels are exposed to a mean Ca(2+) concentration on the order of 10 microM during a Ca(2+) spark

Ca(2+) sparks are small, localized cytosolic Ca(2+) transients due to Ca(2+) release from sarcoplasmic reticulum through ryanodine receptors. In smooth muscle, Ca(2+) sparks activate large conductance Ca(2+)-activated K(+) channels (BK channels) in the spark microdomain, thus generating spontaneous transient outward currents (STOCs). The purpose of the present study is to determine experimentally the level of Ca(2+) to which the BK channels are exposed during a spark. Using tight seal, whole-cell recording, we have analyzed the voltage-dependence of the STOC conductance (g((STOC))), and compared it to the voltage-dependence of BK channel activation in excised patches in the presence of different [Ca(2+)]s. The Ca(2+) sparks did not change in amplitude over the range of potentials of interest. In contrast, the magnitude of g((STOC)) remained roughly constant from 20 to -40 mV and then declined steeply at more negative potentials. From this and the voltage dependence of BK channel activation, we conclude that the BK channels underlying STOCs are exposed to a mean [Ca(2+)] on the order of 10 microM during a Ca(2+) spark. The membrane area over which a concentration \u3e or =10 microM is reached has an estimated radius of 150-300 nm, corresponding to an area which is a fraction of one square micron. Moreover, given the constraints imposed by the estimated channel density and the Ca(2+) current during a spark, the BK channels do not appear to be uniformly distributed over the membrane but instead are found at higher density at the spark site

Low-light Environment Neural Surveillance

We design and implement an end-to-end system for real-time crime detection in low-light environments. Unlike Closed-Circuit Television, which performs reactively, the Low-Light Environment Neural Surveillance provides real time crime alerts. The system uses a low-light video feed processed in real-time by an optical-flow network, spatial and temporal networks, and a Support Vector Machine to identify shootings, assaults, and thefts. We create a low-light action-recognition dataset, LENS-4, which will be publicly available. An IoT infrastructure set up via Amazon Web Services interprets messages from the local board hosting the camera for action recognition and parses the results in the cloud to relay messages. The system achieves 71.5% accuracy at 20 FPS. The user interface is a mobile app which allows local authorities to receive notifications and to view a video of the crime scene. Citizens have a public app which enables law enforcement to push crime alerts based on user proximity.Comment: Pre-print, accepted to IEEE International Workshop on Machine Learning for Signal Processing 2020 Conference Proceedings. Code and dataset are available at https://github.com/mcgridles