A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e ± p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q 2 , and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.

Beauty production in deep inelastic scattering with events in which a muon and a jet are observed in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb −1 . The fraction of events with beauty quarks in the data was determined using the distribution of the transverse momentum of the muon relative to the jet. The cross section for beauty production was measured in the kinematic range of photon virtuality, Q 2 > 2 GeV 2 , and inelasticity, 0.05 < y < 0.7, with the requirement of a muon and a jet. Total and differential cross sections are presented and compared to QCD predictions. The beauty contribution to the structure function F 2 was extracted and is compared to theoretical predictions.

The flux of impurity atoms into plasmas from limiting surfaces is considered. It is shown how the flux of an impurity released from a surface can be derived from spectroscopic measurements along a line-of-sight directed at the surface. A theoretical atomic level population model is developed to obtain the "ionization per emitted photon" quantities which link the spectroscopic measurement to the flux. Metastable states and finite density plasma effects are taken into account and observations at visible wavelengths are emphasized. Detailed studies and calculations are performed for C+', C+ ', O+', O+', Cr, Cr+ I , Fe, Fe+ I , Ni and Ni+ I . Tabulations and graphs of relevant quantities are provided. The application of the theory to impurity influxes in the JET Tokamak is described.

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Abstract. Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb −1 . The measurements were made in the kinematic range Q 2 < 1 GeV 2 , 0.20 < y < 0.85 and x IP < 0.025, where Q 2 is the photon virtuality, y is the inelasticity and x IP is the fraction of the proton momentum taken by the diffractive exchange. The two jets with the highest transverse energy, E jet T , were required to satisfy E jet T > 7.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range −1.5 < η jet < 1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton.

Dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd). Previous studies indicated that Bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that Bd ceases growth at temperatures above 28°C. Here we investigate how small-scale variations in water temperature correlate with Bd prevalence in the wild. We sampled 221 amphibians, including 201 lowland leopard frogs (Rana [Lithobates] yavapaiensis), from 12 sites in Arizona, USA, and tested them for Bd. Amphibians were encountered in microhabitats that exhibited a wide range of water temperatures (10–50°C), including several geothermal water sources. There was a strong inverse correlation between the water temperature in which lowland leopard frogs were captured and Bd prevalence, even after taking into account the influence of year, season, and host size. In locations where Bd was known to be present, the prevalence of Bd infections dropped from 75–100% in water <15°C, to less than 10% in water >30°C. A strong inverse correlation between Bd infection status and water temperature was also observed within sites. Our findings suggest that microhabitats where water temperatures exceed 30°C provide lowland leopard frogs with significant protection from Bd, which could have important implications for disease dynamics, as well as management applications. There must be quite a few things a hot bath won't cure, but I don't know many of them - Sylvia Plath, “The Bell Jar” (1963).

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