An investigation into the factors involved in acclimatization to temperature and death at high temperature in calliphora erythrocephala (meig)

The heat resistance of Calliphora erythrocephala varies during the life history. The egg is most sensitive to high temperature and the puparium most resistant. Puparial resistance develops in the larval stage and declines in the young adult. This adult decline is temperature dependent and seems to be related to changes taking place during maturation. Evidence for the existence of development acclimatization was found to be contradictory, however, physiological acclimatization did occur in the adult. This latter form of acclimatization differs from the typical pattern observed with other species, for the increase in heat resistance with increasing temperature of acclimatization is not proportionate and it declines with adult age. The interaction of these factors makes resistance adaptation in Calliphora erythrocephala a complex phenomena. It is concluded that the primary lesion of heat death in adults is the uncoupling of the sarcosomal enzymes associated with oxidative phosphorylation of ɤ glycerophosphate. The heat sensitivity of this enzyme pathway is correlated with the heat death point of the whole animal and death is probably the result of a breakdown in ATF synthesis, which leads to the interruption of other energy dependent processes. The biochemical lesions during heat death are correlated with dramatic changes in the ultrastructure of sarcosomal cristae, which house the respiratory assemblies. This suggests that the structural and functional integrity of membrane-enzyme complexes are important factors in cellular metabolism. Studies on isolated sarcosomes have shown that the coupling of oxidative phosphorylation is influenced by both age and acclimatized state of the fly. The coupling enzymes are implicated in both the age dependent changes in heat resistance and also capacity adaptation. They are likely to be key factors in the temperature physiology of adult Calliphora

Post-Impact Thermal Evolution of Porous Planetesimals

Impacts between planetesimals have largely been ruled out as a heat source in the early Solar System, by calculations that show them to be an inefficient heat source and unlikely to cause global heating. However, the long-term, localized thermal effects of impacts on planetesimals have never been fully quantified. Here, we simulate a range of impact scenarios between planetesimals to determine the post-impact thermal histories of the parent bodies, and hence the importance of impact heating in the thermal evolution of planetesimals. We find on a local scale that heating material to petrologic type 6 is achievable for a range of impact velocities and initial porosities, and impact melting is possible in porous material at a velocity of > 4 km/s. Burial of heated impactor material beneath the impact crater is common, insulating that material and allowing the parent body to retain the heat for extended periods (~ millions of years). Cooling rates at 773 K are typically 1 - 1000 K/Ma, matching a wide range of measurements of metallographic cooling rates from chondritic materials. While the heating presented here is localized to the impact site, multiple impacts over the lifetime of a parent body are likely to have occurred. Moreover, as most meteorite samples are on the centimeter to meter scale, the localized effects of impact heating cannot be ignored.Comment: 38 pages, 9 figures, Revised for Geochimica et Cosmochimica Acta (Sorry, they do not accept LaTeX

Design data collection with Skylab/EREP microwave instrument S-193

There are no author-identified significant results in this report

Healthcare use among preschool children attending GP-led urgent care centres: a descriptive, observational study

© 2015 Published by the BMJ Publishing Group Limited.Objective Urgent care centres (UCCs) hours were developed with the aim of reducing inappropriate emergency department (ED) attendances in England. We aimed to examine the presenting complaint and outcomes of care in 2 general practitioner (GP)-led UCCs with extended opening times. Design Retrospective observational epidemiological study using routinely collected data. Setting 2 GP-led UCCs in London, colocated with a hospital ED. Participants All children aged under 5 years, attending 2 GP-led UCCs over a 3-year period. Outcomes Outcomes of care for the children including: primary diagnosis; registration status with a GP; destination following review within the UCC; and any medication prescribed. Comparison between GP-led UCC visit rates and routine general practices was also made. Results 3% (n=7747/282 947) of all attenders at the GP-led UCCs were children aged under 5 years. The most common reason for attendance was a respiratory illness (27%), followed by infectious illness (17%). 18% (n=1428) were either upper respiratory tract infections or viral infections. The majority (91%) of children attending were registered with a GP, and over two-thirds of attendances were out of hours. Overall 79% were seen and discharged home. Preschool children were more likely to attend their GP (47.0 per 100) than a GP-led UCC (9.4 per 100; 95% CI 8.9 to 10.0). Conclusions Two-thirds of preschool children attending GP-led UCCs do so out of hours, despite the majority being registered with a GP. The case mix is comparable with those presenting to an ED setting, with the majority managed exclusively by the GPs in the UCC before discharge home. Further work is required to understand the benefits of a GP-led urgent system in influencing future use of services especially emergency care

Simple strong glass forming models: mean-field solution with activation

We introduce simple models, inspired by previous models for froths and covalent glasses, with trivial equilibrium properties but dynamical behaviour characteristic of strong glass forming systems. These models are also a generalization of backgammon or urn models to a non--constant number of particles, where entropic barriers are replaced by energy barriers, allowing for the existence of activated processes. We formulate a mean--field version of the models, which keeps most of the features of the finite dimensional ones, and solve analytically the out--of--equilibrium dynamics in the low temperature regime where activation plays an essential role.Comment: 18 pages, 9 figure

Reliable estimation of prediction uncertainty for physico-chemical property models

The predictions of parameteric property models and their uncertainties are sensitive to systematic errors such as inconsistent reference data, parametric model assumptions, or inadequate computational methods. Here, we discuss the calibration of property models in the light of bootstrapping, a sampling method akin to Bayesian inference that can be employed for identifying systematic errors and for reliable estimation of the prediction uncertainty. We apply bootstrapping to assess a linear property model linking the 57Fe Moessbauer isomer shift to the contact electron density at the iron nucleus for a diverse set of 44 molecular iron compounds. The contact electron density is calculated with twelve density functionals across Jacob's ladder (PWLDA, BP86, BLYP, PW91, PBE, M06-L, TPSS, B3LYP, B3PW91, PBE0, M06, TPSSh). We provide systematic-error diagnostics and reliable, locally resolved uncertainties for isomer-shift predictions. Pure and hybrid density functionals yield average prediction uncertainties of 0.06-0.08 mm/s and 0.04-0.05 mm/s, respectively, the latter being close to the average experimental uncertainty of 0.02 mm/s. Furthermore, we show that both model parameters and prediction uncertainty depend significantly on the composition and number of reference data points. Accordingly, we suggest that rankings of density functionals based on performance measures (e.g., the coefficient of correlation, r2, or the root-mean-square error, RMSE) should not be inferred from a single data set. This study presents the first statistically rigorous calibration analysis for theoretical Moessbauer spectroscopy, which is of general applicability for physico-chemical property models and not restricted to isomer-shift predictions. We provide the statistically meaningful reference data set MIS39 and a new calibration of the isomer shift based on the PBE0 functional.Comment: 49 pages, 9 figures, 7 table

Statistical Mechanics of Two-dimensional Foams

The methods of statistical mechanics are applied to two-dimensional foams under macroscopic agitation. A new variable -- the total cell curvature -- is introduced, which plays the role of energy in conventional statistical thermodynamics. The probability distribution of the number of sides for a cell of given area is derived. This expression allows to correlate the distribution of sides ("topological disorder") to the distribution of sizes ("geometrical disorder") in a foam. The model predictions agree well with available experimental data

Deterministic Partial Differential Equation Model for Dose Calculation in Electron Radiotherapy

Treatment with high energy ionizing radiation is one of the main methods in modern cancer therapy that is in clinical use. During the last decades, two main approaches to dose calculation were used, Monte Carlo simulations and semi-empirical models based on Fermi-Eyges theory. A third way to dose calculation has only recently attracted attention in the medical physics community. This approach is based on the deterministic kinetic equations of radiative transfer. Starting from these, we derive a macroscopic partial differential equation model for electron transport in tissue. This model involves an angular closure in the phase space. It is exact for the free-streaming and the isotropic regime. We solve it numerically by a newly developed HLLC scheme based on [BerCharDub], that exactly preserves key properties of the analytical solution on the discrete level. Several numerical results for test cases from the medical physics literature are presented.Comment: 20 pages, 7 figure

Reconstruction from Radon projections and orthogonal expansion on a ball

The relation between Radon transform and orthogonal expansions of a function on the unit ball in \RR^d is exploited. A compact formula for the partial sums of the expansion is given in terms of the Radon transform, which leads to algorithms for image reconstruction from Radon data. The relation between orthogonal expansion and the singular value decomposition of the Radon transform is also exploited.Comment: 15 page