676 research outputs found

    Effects of Secondary Electron Emission on Charge Pulses from a Z-Stack Microchnnel Plate Photon Counting Detector with a Crossed Delay Line Anode Readout

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    A study of the effects of secondary electron emission on charge pulses from a microchannel plate (MCPs) photon counting detector with crossed delay line (CDL) anode readout is presented. The detector is a two-dimensional photon counting detector with fast count rate and good spatial resolution being developed at Los Alamos National Laboratory. The CDL anode is constructed of two orthogonal planar pairs of helically wound wires on inner and outer ceramic sides attached to a copper ground plane. The electron cloud event from the MCPs interacts with the wires generating a signal pulse. The electrons that strike the wire with sufficient energy generate secondary electrons. A model is presented for the charge pulses from the CDL anode incorporating the effects of secondary electron emission. An empirical test of the model is conducted with two different wire materials using a demountable MCP/CDL detector. Charge pulses are measured and the results are compared to the model. The results show that the charge pulses from the CDL anode are material dependent and exhibit the general behavior predicted by the model. Secondary electron emission is an integral part of the CDL anode charge pulses and must be considered in further developments of the CDL anode readout

    Branding private higher education institutions in South Africa through the evaluation of current branding models

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    The current Private Higher Education Institution (PHEI) landscape in South Africa is developing at a rapid rate, with over ninety private tertiary institutions, registered with the Council for Higher Education (CHE). However, stakeholder perceptions of these PHEIs are generally negative, largely as a result of the negative perceptions of the qualification, obtained from the private institutions by both parents and students, and questions around the sustainability of the institutions in the long run. Media reports, lack of Department of Education (DHET) support and funding, as well as minimum, if any, marketing and advertising from the PHEI are factors, cited for these firmly entrenched perceptions from the general public. The article was driven by both current and emerging branding models as a benchmark for value-added branding of PHEIs in South Africa. International markets, in countries such as Singapore, Malaysia, India and Brazil are included; not as a comparative study, but more as a review of literature on how tertiary education is branded in the private sector in these countries. In addition, developing countries and emerging markets needed to be taken into consideration in the light of their experience in sustaining private education entities. The subsequent investigation of these models proved invaluable in respect of providing similarities and, in some instances, huge differences, which contributed to the establishment of a generic value-added branding model critical for sustaining PHEIs in South Africa. The knowledge of which dimensions the branding of a PHEI should focus on to nullify the negative perceptions associated with a PHEI is paramount.Key Words: Sustainability of Private Higher Educations Instituions / Negative perceptions/Dimensions of branding/ Branding models&nbsp

    CELiS (Compact Eyesafe Lidar System): A Portable 1.5 ÎĽm Elastic Lidar System for Rapid Aerosol Concentration Measurement

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    CELiS (Compact Eyesafe Lidar System) is a tactical elastic lidar system commissioned by the Strategic Environmental Research and Development Program (SERDP) for the purpose of air quality environmental compliance issues surrounding the offroad use of wheeled and tracked vehicles. A complete CELiS instrument weighs less than 300 lbs., is less than 2 cubic meters in volume and uses 700 W of 120V AC power. CELiS has a working range of better than 2km and a range resolution of 5m

    X-linked Malformation and Infantile Lethality Syndrome (provisionally named Ogden Syndrome)

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    This is a lethal X-linked disorder of infancy comprising a distinct combination of distinctive craniofacial features producing an aged appearance, growth failure, hypotonia, global developmental delays, cryptorchidism, and acquired cardiac arrhythmias. The first family was identified in Ogden, Utah, with five affected boys in two generations of family members. A mutation was identified as a c.109T>C(p.Ser37Pro) variant in NAA10, a gene encoding the catalytic subunit of the major human N-terminal acetyltransferase (NatA). This same mutation was identified in a second unrelated family, with three affected boys in two generations. This X-linked Malformation and Infantile Lethality Syndrome has provisionally been named Ogden Syndrome, in honor of the hometown where the first family resides

    Autosomal dominant retinitis pigmentosa with apparent incomplete penetrance: a clinical, electrophysiological, psychophysical, and molecular genetic study

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    7 páginas, 7 figuras, 4 tablas.-- Licence Creative Commons, attribution, Non-commercial licence.-- et al.Twenty five symptomatic individuals and six asymptomatic obligate gene carriers from four families with autosomal dominant retinitis pigmentosa (adRP) showing apparent incomplete penetrance have been studied. Symptomatic individuals from three families showed early onset of night blindness, non-recordable rod electroretinograms, and marked elevation of both rod and cone thresholds in all subjects tested. In the fourth family, there was more variation in the age of onset of night blindness and some symptomatic individuals showed well preserved rod and cone function in some retinal areas. All asymptomatic individuals tested had evidence of mild abnormalities of rod and cone function, indicating that these families show marked variation in expressivity rather than true non-penetrance of the adRP gene. No mutations of the rhodopsin or RDS genes were found in these families and the precise genetic mutation(s) remain to be identified.This study was supported by the Medical Research Council (UK), The Weilcome Trust, British Retinitis Pigmentosa Society, and the National Retinitis Pigmentosa Society, Fighting Blindness, USA.Peer reviewe

    Passenger casualties in non-collision incidents on buses and coaches in Great Britain

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    Of all the killed or seriously injured (KSI) passengers on buses or coaches in Great Britain, a surprisingly high proportion, 64.3%, are injured in non-collision incidents. A KSI casualty distribution of this sub-sample identifies that 74.2% of the casualties are female and a large proportion, 58.0%, are elderly casualties 60 years of age or over

    Interventions in Agriculture for Nutrition Outcomes: A Systematic Review Focused on South Asia

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    Research on the potential impact of interventions in agriculture on nutrition outcomes is of particular relevance in South Asia where agriculture-related activities are a major source of livelihoods for large sections of society and where the population suffers from one of the highest global burdens of malnutrition in all its forms. This systematic review aims to assess the strength of the available evidence that agricultural interventions have an impact on intermediate and final nutrition outcomes in India, Bangladesh, Nepal, Pakistan and Afghanistan. We searched five literature databases and reference lists of previous systematic reviews to identify peer-reviewed studies published between 2012 and 2017, detailing impacts of household- or farm-level agricultural interventions on nutritional outcomes in South Asia. We identified six intervention studies (reported in nine papers) conducted in Bangladesh (two studies), India (two studies) and Nepal (two studies). The majority of studies examined the impact of provision of seed, plants and training to increase home garden fruit and vegetable production with or without integrated poultry provision and training. Other studies evaluated the impact of livestock or aquaculture provision and training. Study designs and quality were mixed; heterogeneity across studies precluded formal meta-analysis. Interventions had a positive impact on intermediate outcomes on the pathway from agricultural intervention to nutritional or health status including dietary quality and dietary diversity of households and individuals (reported in seven papers). The evidence on the impact on final nutritional outcomes was mixed: one paper reported that home gardens with poultry reduced the odds of anaemia but there was no convincing evidence of an impact of agricultural interventions on child anthropometric measurement (reported in four papers). In recent years, the Leveraging Agriculture for Nutrition in South Asia (LANSA) research programme consortium has significantly expanded research on agricultural interventions for nutrition outcomes by conducting and commissioning a suite of formative and feasibility studies that have extended both the range and geographic location of interventions under study. This expanding body of research should, in the future, enable the identification of cost-effective interventions to enhance the impact of agricultural interventions sustainably to improve nutrition outcomes especially in women and children in South Asia

    Five feet high and rising : cities and flooding in the 21st century

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    Urban flooding is an increasingly important issue. Disaster statistics appear to show flood events are becoming more frequent, with medium-scale events increasing fastest. The impact of flooding is driven by a combination of natural and human-induced factors. As recent flood events in Pakistan, Brazil, Sri Lanka and Australia show, floods can occur in widespread locations and can sometimes overwhelm even the best prepared countries and cities. There are known and tested measures for urban flood risk management, typically classified as structural or engineered measures, and non-structural, management techniques. A combination of measures to form an integrated management approach is most likely to be successful in reducing flood risk. In the short term and for developing countries in particular, the factors affecting exposure and vulnerability are increasing at the fastest rate as urbanization puts more people and more assets at risk. In the longer term, however, climate scenarios are likely to be one of the most important drivers of future changes in flood risk. Due to the large uncertainties in projections of climate change, adaptation to the changing risk needs to be flexible to a wide range of future scenarios and to be able to cope with potentially large changes in sea level, rainfall intensity and snowmelt. Climate uncertainty and budgetary, institutional and practical constraints are likely to lead to a combining of structural and non-structural measures for urban flood risk management, and arguably, to a move away from what is sometimes an over-reliance on hard-engineered defenses and toward more adaptable and incremental non-structural solutions.Hazard Risk Management,Wetlands,Natural Disasters,Adaptation to Climate Change,Climate Change Impacts
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