6,886 research outputs found

    High impact activities in parks: best management practice and future research

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    Off-road driving, horseriding, rock climbing and similar activities can be lucrative for tour operators and important for local recreational groups, but contentious for management of national parks and protected areas, both because of safety and liability and because of potentially high environmental impacts. These include spreading weeds and pathogens, starting fires and crushing bird nests on beaches, amongst many others. In Australia as elsewhere, off-road vehicles and horses are allowed only in some places in some parks, and often only under permit. We have very little reliable scientific information to-date on just how serious these impacts may be, and on how well they might be managed through minimal-impact practices such as vehicle washdowns, stockfeed processing and seasonal closures. Such information can only be obtained through site specific ecological studies of the plants, animals and watercourses likely to be affected, differentiating tourism impacts from natural causes and fluctuations. This report examines management strategies for these activities worldwide and in Australia. Suggestions for best management practice and future research agendas are set

    Biochemical diagnosis of ventricular dysfunction in elderly patients in general practice: observational study

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    Objective: To investigate the usefulness of measuring plasma concentrations of B type natriuretic peptide in the diagnosis of left ventricular systolic dysfunction in an unselected group of elderly people. Design: Observational study. Setting: General practice with four centres in Poole, Dorset. Participants: 155 elderly patients aged 70 to 84 years. Main outcome measures: Diagnostic characteristics of plasma B type natriuretic peptide measured by radioimmunoassay as a test for left ventricular systolic dysfunction assessed by echocardiography. Results: The median plasma concentration of B type natriuretic peptide was 39.3 pmol/l in patients with left ventricular systolic dysfunction and 15.8 pmol/l in those with normal function. The proportional area under the receiver operator curve was 0.85. At a cut-off point of 18.7 pmol/l the test sensitivity was 92% and the predictive value 18%. Conclusions: Plasma concentration of B type natriuretic peptide could be used effectively as an initial test in a community screening programme and, possibly, using a low cut-off point, as a means of ruling out left ventricular systolic dysfunction. It is, however, not a good test to “rule in” the diagnosis, and access to echocardiography remains essential for general practitioners to diagnose heart failure early

    Social Effects in Science: Modelling Agents for a Better Scientific Practice

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    Science is a fundamental human activity and we trust its results because it has several error-correcting mechanisms. Its is subject to experimental tests that are replicated by independent parts. Given the huge amount of information available, scientists have to rely on the reports of others. This makes it possible for social effects to influence the scientific community. Here, an Opinion Dynamics agent model is proposed to describe this situation. The influence of Nature through experiments is described as an external field that acts on the experimental agents. We will see that the retirement of old scientists can be fundamental in the acceptance of a new theory. We will also investigate the interplay between social influence and observations. This will allow us to gain insight in the problem of when social effects can have negligible effects in the conclusions of a scientific community and when we should worry about them.Comment: 14 pages, 5 figure

    A comparison of different ways of including baseline counts in negative binomial models for data from falls prevention trials

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    This is the author accepted manuscript. The final version is available from Wiley-VCH Verlag via the DOI in this record.A common design for a falls prevention trial is to assess falling at baseline, randomize participants into an intervention or control group, and ask them to record the number of falls they experience during a follow-up period of time. This paper addresses how best to include the baseline count in the analysis of the follow-up count of falls in Negative Binomial (NB) regression. We examine the performance of various approaches in simulated datasets where both counts are generated from a mixed Poisson distribution with shared random subject effect. Including the baseline count after log-transformation as a regressor in NB regression (NB-logged) or as an offset (NB-offset) resulted in greater power than including the untransformed baseline count (NB-unlogged). Cook and Wei's Conditional Negative Binomial (CNB) model replicates the underlying process generating the data. In our motivating dataset, a statistically significant intervention effect resulted from the NB-logged, NB-offset and CNB models, but not from NB-unlogged, and large, outlying baseline counts were overly influential in NB-unlogged but not in NB-logged. We conclude that there is little to lose by including the log-transformed baseline count in standard NB regression compared to CNB for moderate to larger sized datasets.Funding Information: National Institute for Health Research, Grant no. RDA/02/06/41; Care South West Peninsul

    Renormalisation Invariance and the Soft ÎČ\beta-Functions

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    We demonstrate that the soft supersymmetry-breaking terms in a N=1 theory can be linked by simple renormalisation group invariant relations which are valid to all orders of perturbation theory. In the special case of finite N=1 theories, the soft terms preserve finiteness to all orders.Comment: 9 pages, tex, Uses harvmac (big

    Valuing initial teacher education at Master's level

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    The future of Master’s-level work in initial teacher education (ITE) in England seems uncertain. Whilst the coalition government has expressed support for Master’s-level work, its recent White Paper focuses on teaching skills as the dominant form of professional development. This training discourse is in tension with the view of professional learning advocated by ITE courses that offer Master’s credits. Following a survey of the changing perceptions of Master’s-level study during a Post Graduate Certificate in Education course by student teachers in four subject groups, this paper highlights how the process of professional learning can have the most impact on how they value studying at a higher level during their early professional development

    Further tests of the atom-annihilation hypothesis as to the origin of the cosmic rays

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    1. Tests in Mexico. The authors had predicted that since the hypothetical silicon-annihilation rays should have enough energy (13.2 Bev) to get vertically through the earth's magnetic field at the equator in Peru, though not in India, there should be found, both at sea level and at all altitudes in the Americas, when vertically incoming rays alone are under test, a very long plateau of uniform cosmic-ray intensities extending north from Mollendo, Peru to about the latitude of Victoria, Mexico (mag. lat. 32.8°). There the strong band due to oxygen annihilation rays (7.5 Bev) should first appear, to be followed in going still further north when the latitude of 40° N magnetic had been reached, by the full entrance of the nitrogen annihilation band (6.5 Bev). The experimental findings were in accord with these predictions. 2. Tests in the United States. In going from Pasadena (mag. lat. 40.7° to St. George, Utah, but 4.1° (280 miles) nearer to the N magnetic pole than Pasadena, the carbon-annihilation band (5.6 Bev) was expected to appear, to be followed by a flat plateau clear up to latitude 54° N magnetic, when helium annihilation rays (1.88 Bev) were expected to appear. A ballon flight at St. George (mag. lat. 44.8°) and another at Pocatello, Idaho (mag. lat. 51°) yielded preliminary results in harmony with these predictions. 3. Evidence that the act of atom-annihilation actually transforms the rest mass energy of an atom into an electron pair. The flat plateau between St. George and Pocatello (mag. lat. 51°) corresponding to the absence of abundant atoms of atomic weight between that of carbon and that of helium, and the definite appearance of a new band between Omaha (mag. lat. 51.3°) and Bismarck (mag. lat. 56°) constitute new and strong evidence for the transformability of the complete rest mass energy of an atom into an electron pair

    Covering California's Kids: The Impact of Healthy Kids on Access, Health Status and Costs

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    Summarizes how the implementation of CHIs designed to improve children's access to primary care helped reduce preventable hospitalizations among lower-income children. Includes policy implications

    Fe I Oscillator Strengths for the Gaia-ESO Survey

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    The Gaia-ESO Public Spectroscopic Survey (GES) is conducting a large-scale study of multi-element chemical abundances of some 100 000 stars in the Milky Way with the ultimate aim of quantifying the formation history and evolution of young, mature and ancient Galactic populations. However, in preparing for the analysis of GES spectra, it has been noted that atomic oscillator strengths of important Fe I lines required to correctly model stellar line intensities are missing from the atomic database. Here, we present new experimental oscillator strengths derived from branching fractions and level lifetimes, for 142 transitions of Fe I between 3526 {\AA} and 10864 {\AA}, of which at least 38 are urgently needed by GES. We also assess the impact of these new data on solar spectral synthesis and demonstrate that for 36 lines that appear unblended in the Sun, Fe abundance measurements yield a small line-by-line scatter (0.08 dex) with a mean abundance of 7.44 dex in good agreement with recent publications.Comment: Accepted for publication in Mon. Not. R. Astron. So
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