645 research outputs found

    Observable Gravity Waves from Supersymmetric Hybrid Inflation II

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    It is shown that a tensor-to-scalar ratio close to r = 0.03, which can be observed by Planck, is realized in supersymmetric hybrid inflation models with TeV-scale soft supersymmetry breaking terms. This extends our previous analysis, which also found r <~ 0.03 but employed intermediate scale soft terms. Other cosmological observables such as the scalar spectral index are in good agreement with the WMAP data.Comment: 4 pages, 4 figure

    GUT Inflation and Proton Decay after WMAP5

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    We employ Coleman-Weinberg and Higgs potentials to implement inflation in non-supersymmetric grand unified theories (GUTs) such as SU(5) and SO(10). To realize a scalar spectral index close to 0.96, as indicated by the most recent WMAP 5-year anlaysis, the energy scale of observable inflation turns out to be of order 101610^{16} GeV. This implies a GUT symmetry breaking scale of similar magnitude, and proton lifetime of order 103410^{34}-103810^{38} years. In some SO(10) models with axion dark matter, the scalar leptoquark boson exchange leads to proton decay with a lifetime of order 103410^{34}-103510^{35} years.Comment: 15 pages, 4 figure

    Observable Gravity Waves From Supersymmetric Hybrid Inflation

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    We identify models of supersymmetric hybrid inflation in which the tensor-to-scalar ratio, a canonical measure of gravity waves produced during inflation, can be as large as 0.03 or so, which will be tested by the Planck satellite experiment. The scalar spectral index lies within the WMAP one sigma bounds, while dns/dlnk0.01|d n_s / d\ln k| \lesssim 0.01.Comment: (v1) 19 pages, 1 table, 3 figures. (v2) 20 pages; updated figures, included additional discussion, footnotes, and referenc

    Minimal Supersymmetric Hybrid Inflation, Flipped SU(5) and Proton Decay

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    Minimal supersymmetric hybrid inflation utilizes a canonical Kahler potential and a renormalizable superpotential which is uniquely determined by imposing a U(1) R-symmetry. In computing the scalar spectral index nsn_s we take into account modifications of the tree level potential caused by radiative and supergravity corrections, as well as contributions from the soft supersymmetry breaking terms with a negative soft mass-squared term allowed for the inflaton. All of these contributions play a role in realizing nsn_s values in the range 0.96-0.97 preferred by WMAP. The U(1) R-symmetry plays an important role in flipped SU(5) by eliminating the troublesome dimension five proton decay. The proton decays into e+π0e^+ \pi^0 via dimension six operators arising from the exchange of superheavy gauge bosons with a lifetime of order 103410^{34}-103610^{36} years.Comment: 14 pages, 8 figure

    Quantification of atopy, lung function and airway hypersensitivity in adults

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    <p>Abstract</p> <p>Background</p> <p>Studies in children have shown that concentration of specific serum IgE (sIgE) and size of skin tests to inhalant allergens better predict wheezing and reduced lung function than the information on presence or absence of atopy. However, very few studies in adults have investigated the relationship of quantitative atopy with lung function and airway hyperresponsiveness (AHR).</p> <p>Objective</p> <p>To determine the association between lung function and AHR and quantitative atopy in a large sample of adults from the UK.</p> <p>Methods</p> <p>FEV<sub>1</sub> and FVC (% predicted) were measured using spirometry and airway responsiveness by methacholine challenge (5-breath dosimeter protocol) in 983 subjects (random sample of 800 parents of children enrolled in a population-based birth cohort enriched with 183 patients with physician-diagnosed asthma). Atopic status was assessed by skin prick tests (SPT) and measurement of sIgE (common inhalant allergens). We also measured indoor allergen exposure in subjects' homes.</p> <p>Results</p> <p>Spirometry was completed by 792 subjects and 626 underwent methacholine challenge, with 100 (16.0%) having AHR (dose-response slope>25). Using sIgE as a continuous variable in a multiple linear regression analysis, we found that increasing levels of sIgE to mite, cat and dog were significantly associated with lower FEV<sub>1</sub> (mite p = 0.001, cat p = 0.0001, dog p = 2.95 × 10<sup>-8</sup>). Similar findings were observed when using the size of wheal on skin testing as a continuous variable, with significantly poorer lung function with increasing skin test size (mite p = 8.23 × 10<sup>-8</sup>, cat p = 3.93 × 10<sup>-10</sup>, dog p = 3.03 × 10<sup>-15</sup>, grass p = 2.95 × 10<sup>-9</sup>). The association between quantitative atopy with lung function and AHR remained unchanged when we repeated the analyses amongst subjects defined as sensitised using standard definitions (sIgE>0.35 kUa/l, SPT-3 mm>negative control).</p> <p>Conclusions</p> <p>In the studied population, lung function decreased and AHR increased with increasing sIgE levels or SPT wheal diameter to inhalant allergens, suggesting that atopy may not be a dichotomous outcome influencing lung function and AHR.</p

    Strontium as a tracer of weathering processes in a silicate catchment polluted by acid atmospheric inputs, Strengbach, France

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    This paper determines the weathering and atmospheric contributions of Ca in surface water from a small spruce forested silicate catchment (N–E France) receiving acid atmospheric inputs. The bedrock is a granite with K-feldspar and albite as dominant phases. The calcium content in plagioclase is low and the Ca/Na ratio in surface water is high, reflecting other sources of calcium from those expected from the weathering of major mineral phases. The biotite content is low. Only traces of apatite were detected while no calcite was found in spite of a major hydrothermal event having affected the granite. The strontium isotopic ratio 87Sr/86Sr and Sr content was used as a tracer of weathering and was determined in minerals and bulk bedrock, open field precipitation, throughfall, soil solution, spring and stream water. The Sr isotopic ratio of the reacting weathering end-member was predicted by simulating the alteration of the granite minerals by incorporating strontium into the water–rock interaction kinetic code KINDIS. In the early stages of water–rock interaction, K-feldspar and biotite strongly influence the isotopic composition of the weathering solution whereas, the Na-rich plagioclase appears to be the main long-term reactive weathering end-member. Approximately 50% of dissolved Sr in streamwater are atmospherically derived. The 87Sr/86Sr ratios of exchangeable Sr in the fine fraction at 1-m depth from a soil profile indicate that the amount of exchangeable Sr seems essentially controlled by atmospheric inputs. The exception is the deep saprolite where weathering processes could supply the Sr (and Ca). Na-Plagioclase weathering obviously control the chemistry and the isotopic composition of surface waters. The weathering of trace mineral plays a secondary role, the exception is for apatite when plagioclase is absent. Our hydrochemical, mineralogical and isotopic investigations show that a major part of the strong Ca losses detected in catchment hydrochemical budgets that result from the neutralization of acid precipitation has an atmospheric origin. Consequently, in the long term, in such areas, the availability of such an exchangeable base cation might be strongly limited and surface waters consequently acidified

    Abrupt transition to heightened poliomyelitis epidemicity in England and Wales, 1947–1957, associated with a pronounced increase in the geographical rate of disease propagation

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    The abrupt transition to heightened poliomyelitis epidemicity in England and Wales, 1947–1957, was associated with a profound change in the spatial dynamics of the disease. Drawing on the complete record of poliomyelitis notifications in England and Wales, we use a robust method of spatial epidemiological analysis (swash-backwash model) to evaluate the geographical rate of disease propagation in successive poliomyelitis seasons, 1940–1964. Comparisons with earlier and later time periods show that the period of heightened poliomyelitis epidemicity corresponded with a sudden and pronounced increase in the spatial rate of disease propagation. This change was observed for both urban and rural areas and points to an abrupt enhancement in the propensity for the geographical spread of polioviruses. Competing theories of the epidemic emergence of poliomyelitis in England and Wales should be assessed in the light of this evidence

    Clinical practice guidelines for the foot and ankle in rheumatoid arthritis: a critical appraisal

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    Background: Clinical practice guidelines are recommendations systematically developed to assist clinical decision-making and inform healthcare. In current rheumatoid arthritis (RA) guidelines, management of the foot and ankle is under-represented and the quality of recommendation is uncertain. This study aimed to identify and critically appraise clinical practice guidelines for foot and ankle management in RA. Methods: Guidelines were identified electronically and through hand searching. Search terms 'rheumatoid arthritis', 'clinical practice guidelines' and related synonyms were used. Critical appraisal and quality rating were conducted using the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument. Results: Twenty-four guidelines were included. Five guidelines were high quality and recommended for use. Five high quality and seven low quality guidelines were recommended for use with modifications. Seven guidelines were low quality and not recommended for use. Five early and twelve established RA guidelines were recommended for use. Only two guidelines were foot and ankle specific. Five recommendation domains were identified in both early and established RA guidelines. These were multidisciplinary team care, foot healthcare access, foot health assessment/review, orthoses/insoles/splints, and therapeutic footwear. Established RA guidelines also had an 'other foot care treatments' domain. Conclusions: Foot and ankle management for RA features in many clinical practice guidelines recommended for use. Unfortunately, supporting evidence in the guidelines is low quality. Agreement levels are predominantly 'expert opinion' or 'good clinical practice'. More research investigating foot and ankle management for RA is needed prior to inclusion in clinical practice guidelines
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