128 research outputs found

    A Monitor of the Focusing Strength of Plasma Lenses Using MeV Synchrotron Radiation

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    The focusing strength of plasma lenses used with high energy electron or positron beams can give rise to synchrotron radiation with critical energies in the MeV range. A method is described for measuring the characteristic energy of this radiation as a way of monitoring the strength of the focus. The principle has been implemented in a plasma lens experiment with a 28.5 GeV positron beam

    Counting Religion in England and Wales: The Long Eighteenth Century, c. 1680–c. 1840

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    The statistical analysis of religion in England and Wales usually commences with the mid-nineteenth century. This article synthesises relevant primary and secondary sources to produce initial quantitative estimates of the religious composition of the population in 1680, 1720, 1760, 1800 and 1840. The Church of England is shown to have lost almost one-fifth of its affiliation market share during this period, with an ever increasing number of nominal Anglicans also ceasing to practise. Nonconformity more than quadrupled, mainly from 1760 and especially after 1800. Roman Catholicism kept pace with demographic growth, but, even reinforced by Irish immigration, remained a limited force in 1840. Judaism and overt irreligion were both negligible.</jats:p

    Learning in Practice: Cost-effectiveness of Continuing Professional Development in Health Care

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    Continuing professional development (CPD) for healthcare professionals is an important strategic instrument for improving health. The Department of Health identifies CPD as a way of maintaining standards of care; improving the health of the nation; and recruiting, motivating, and retaining high quality staff. To this end, direct NHS spending on continuing professional development in 1999-2000 was about £1bn ($1.6bn). If we regard CPD as any method to improve health professionals’ skills the total resources devoted to it are probably much greater, particularly with the recent increased participation in response to the need for recertification and revalidation. To ensure the maximum gain from participation in CPD, these resources must be used efficiently. To assess the efficiency of participating in CPD, economic criteria are needed. Resources for health care are scarce, and money spent on CPD could otherwise be used for direct patient care. These opportunity costs are explicitly considered in the economic methods of cost benefit analysis and cost effectiveness analysis. The literature contains various reviews of cost effectiveness analysis in both health care and education. Such articles explain why cost effectiveness analysis (or another method of economic evaluation) is essential and how such evaluation should be undertaken, and they clearly define the set of economic terms (such as cost benefit analysis, cost effectiveness analysis, rate of return, and opportunity cost) that need to be incorporated into this type of research. Casebeer et al highlighted the need for economic evaluation of CPD activities, but they emphasised the use of cost benefit analysis, which requires monetary values to be assigned to measures of effectiveness. Cost benefit analysis is generally used to ascertain whether an intervention should be undertaken. Cost effectiveness analysis is used to decide which interventions (out of a number of alternatives) should be undertaken. However, cost effectiveness analysis in education research is rare. This is partly because of limited training for researchers, antipathy toward (economic) analysis that might constrain policy, and the dearth of significant results in studies of educational effectiveness.9 The quality of such research is also often poor: Clune found that only 1% of 541 “cost-effectiveness” studies of elementary and secondary education between 1991 and 1996 could be considered reliable, with strong design and analysis. In contrast, economic evaluation of healthcare technologies is increasing, and the methods for making such analysis are rapidly evolving. (Even here, however, critical reviews identify a substantial number of weak cost benefit and cost effectiveness analyses.

    Tipping back the balance: recolonization of the Macquarie Island isthmus by king penguins (Aptenodytes patagonicus) following extermination for human gain

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    During the late 19th and early 20th centuries, when blubber oil fuelled house lamps, the king penguin population at Macquarie Island was reduced from two very large (perhaps hundreds of thousands of birds) colonies to about 3000 birds. One colony, located on the isthmus when the island was discovered in 1810, was extinct by 1894 and it took about 100 years for king penguins to re-establish a viable breeding population there. Here we document this recovery. The first eggs laid at Gadget Gully on the isthmus were recorded in late February 1995 but in subsequent years egg laying took place earlier between November and February (this temporal discontinuity is a consequence of king penguin breeding behaviour). The first chick was hatched in April 1995 but the first fledging was not raised until the following breeding season in October 1996. The colony increased on average 66% per annum in the five years between 1995 and 2000. King penguins appear resilient to catastrophic population reductions, and as the island\u27s population increases, it is likely that other previously abandoned breeding sites will be reoccupied

    co_LAB - Project 1

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    co_LAB is an interdisciplinary, educational project which houses intensive teaching programmes, the first of which took place between 12-16 May, 2014. co_LAB was designed to explore and develop new approaches to collaborative teaching and learning through the use of networked digital tools, and through the transferral of knowledge, skillsets and teaching styles. co_LAB aims to overcome the traditional barriers between individual course specialisms by bringing together students and colleagues from across academic disciplines to collaborate on transmedia design projects. co_LAB team: Martyn Thayne, James Field, Graham Cooper, Rob Coley, Richard Vickers, Adam Verity, Clive McCarthy (special thanks to Louise Lawlor, Mike Downing, Mark Aldridge, John Murray, Chris Heydra (The Hague University of Applied Sciences

    Observation of the Askaryan Effect: Coherent Microwave Cherenkov Emission from Charge Asymmetry in High Energy Particle Cascades

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    We present the first direct experimental evidence for the charge excess in high energy particle showers predicted nearly 40 years ago by Askaryan. We directed bremsstrahlung photons from picosecond pulses of 28.5 GeV electrons at the SLAC Final Focus Test Beam facility into a 3.5 ton silica sand target, producing electromagnetic showers several meters long. A series of antennas spanning 0.3 to 6 GHz were used to detect strong, sub-nanosecond radio frequency pulses produced whenever a shower was present. The measured electric field strengths are consistent with a completely coherent radiation process. The pulses show 100% linear polarization, consistent with the expectations of Cherenkov radiation. The field strength versus depth closely follows the expected particle number density profile of the cascade, consistent with emission from excess charge distributed along the shower. These measurements therefore provide strong support for experiments designed to detect high energy cosmic rays and neutrinos via coherent radio emission from their cascades.Comment: 10 pages, 4 figures. Submitted to Phys. Rev. Let

    Dark sectors 2016 Workshop: community report

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    This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years

    First recorded eruption of Nabro volcano, Eritrea, 2011

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    We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of re- gional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodi- gious quantity of SO2 emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic signifi- cance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of Editorial responsibility: G. Giordano the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shal- low, NW–SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response miti- gated the human costs of the eruption

    Antiviral Lead Compounds from Marine Sponges

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    Marine sponges are currently one of the richest sources of pharmacologically active compounds found in the marine environment. These bioactive molecules are often secondary metabolites, whose main function is to enable and/or modulate cellular communication and defense. They are usually produced by functional enzyme clusters in sponges and/or their associated symbiotic microorganisms. Natural product lead compounds from sponges have often been found to be promising pharmaceutical agents. Several of them have successfully been approved as antiviral agents for clinical use or have been advanced to the late stages of clinical trials. Most of these drugs are used for the treatment of human immunodeficiency virus (HIV) and herpes simplex virus (HSV). The most important antiviral lead of marine origin reported thus far is nucleoside Ara-A (vidarabine) isolated from sponge Tethya crypta. It inhibits viral DNA polymerase and DNA synthesis of herpes, vaccinica and varicella zoster viruses. However due to the discovery of new types of viruses and emergence of drug resistant strains, it is necessary to develop new antiviral lead compounds continuously. Several sponge derived antiviral lead compounds which are hopedto be developed as future drugs are discussed in this review. Supply problems are usually the major bottleneck to the development of these compounds as drugs during clinical trials. However advances in the field of metagenomics and high throughput microbial cultivation has raised the possibility that these techniques could lead to the cost-effective large scale production of such compounds. Perspectives on biotechnological methods with respect to marine drug development are also discussed
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