Analysis of radiation damage in silicon solar cells and annealing or compensation of damage by impurities Final report, 7 Jan. 1964 - 21 Apr. 1966

Radiation damage in silicon solar cells and annealing or compensation of damage by impuritie

The effect of different forms of heparin on point-of-care blood gas analysis

Background. Point-of-care blood gas analysis plays an integral role in the management of critically ill and injured patients presenting to the emergency department (ED). While the use of specially manufactured syringes containing electrolyte-balanced dried heparin is recommended when processing these specimens, alternatives including manually self-prepared syringes washed with liquid heparin or heparin vacutainers are still often used.Objectives. To assess the effect of two concentrations of liquid heparin and the use of heparin vacutainers on the reliability of blood gas analysis results compared with the recommended standard of dried heparin syringes in the ED setting.Methods. Blood samples were drawn from 54 patients attending a tertiary-level hospital ED. Individual samples were distributed equally among each of four different collection devices: a dried heparin syringe, self-prepared syringes washed separately with 1 000 IU/mL and 5 000 IU/mL liquid heparin, and a heparin vacutainer. Results obtained from the standard dried heparin syringes were compared with those from the other three methods.Results. For both the liquid heparin cohorts, partial pressure of carbon dioxide (pCO2), potassium (K+), sodium (Na+), ionised calcium (iCa2+) and haemoglobin had >20% of results falling beyond the total allowable error. iCa2+ and K+ results were most affected in the 5 000 IU/mL cohort and iCa2+ and Na+ in the 1 000 IU/ml cohort. pCO2, pH and iCa2+ were the most significantly affected in the heparin vacutainer cohort.Conclusions. Use of liquid heparin can result in significant negative bias in the majority of blood gas analytes, especially electrolytes. Heparin vacutainer use can result in unacceptable variations in the respiratory analytes. While standard dried heparin syringes may not always be available, it is of vital importance that practitioners be aware of these biases and limitations when using substitutes

Topological defects, pattern evolution, and hysteresis in thin magnetic films

Nature of the magnetic hysteresis for thin films is studied by the Monte-Carlo simulations. It is shown that a reconstruction of the magnetization pattern with external field occurs via the creation of vortex-antivortex pairs of a special kind at the boundaries of stripe domains. It is demonstrated that the symmetry of order parameter is of primary importance for this problem, in particular, the in-plane magnetic anisotropy is necessary for the hysteresis.Comment: Accepted to EPL; 7 pages, 3 color figure

Stabilization of microbial communities by responsive phenotypic switching

Clonal microbes can switch between different phenotypes and recent theoretical work has shown that stochas-tic switching between these subpopulations can stabilize microbial communities. This phenotypic switching need not be stochastic, however, but could also be in response to environmental factors, both biotic and abiotic. Here, motivated by the bacterial persistence phenotype, we explore the ecological effects of such responsive switching by analyzing phenotypic switching in response to competing species. We show that the stability of microbial communities with responsive switching differs generically from that of communities with stochastic switching only. To understand the mechanisms by which responsive switching stabilizes coexistence, we go on to analyze simple two-species models. Combining exact results and numerical simulations, we extend the classical stability results for the competition of two species without phenotypic variation to the case in which one species switches, stochastically and responsively, between two phenotypes. In particular, we show that responsive switching can stabilize coexistence even when stochastic switching on its own does not affect the stability of the community

DSMC Modeling Of Gasdynamics, Radiation And Fine Particulates In Ionian Volcanic Jets

Aerospace Engineerin

Evolutionary quantum cosmology in a gauge-fixed picture

We study the classical and quantum models of a flat Friedmann-Robertson-Walker (FRW) space-time, coupled to a perfect fluid, in the context of the consensus and a gauge-fixed Lagrangian frameworks. It is shown that, either in the usual or in the gauge-fixed actions, the evolution of the universe based on the classical cosmology represents a late time power law expansion, coming from a big-bang singularity in which the scale factor goes to zero for the standard matter, and tending towards a big-rip singularity in which the scale factor diverges for the phantom fluid. We then employ the familiar canonical quantization procedure in the given cosmological setting to find the cosmological wave functions in the corresponding minisuperspace. Using a gauge-fixed (reduced) Lagrangian, we show that, it may lead to a Schr\"{o}dinger equation for the quantum-mechanical description of the model under consideration, the eigenfunctions of which can be used to construct the time dependent wave function of the universe. We use the resulting wave function in order to investigate the possibility of the avoidance of classical singularities due to quantum effects by means of the many-worlds and ontological interpretation of quantum cosmology.Comment: 15 pages, 10 figures, typos corrected, Refs. adde

Scaling of the electron dissipation range of solar wind turbulence

Electron scale solar wind turbulence has attracted great interest in recent years. Clear evidences have been given from the Cluster data that turbulence is not fully dissipated near the proton scale but continues cascading down to the electron scales. However, the scaling of the energy spectra as well as the nature of the plasma modes involved at those small scales are still not fully determined. Here we survey 10 years of the Cluster search-coil magnetometer (SCM) waveforms measured in the solar wind and perform a statistical study of the magnetic energy spectra in the frequency range [$1, 180$]Hz. We show that a large fraction of the spectra exhibit clear breakpoints near the electon gyroscale $\rho_e$, followed by steeper power-law like spectra. We show that the scaling below the electron breakpoint cannot be determined unambiguously due to instrumental limitations that will be discussed in detail. We compare our results to recent ones reported in other studies and discuss their implication on the physical mechanisms and the theoretical modeling of energy dissipation in the SW.Comment: 10 pages, submitte

Stability of self-referent encoding task performance and associations with change in depressive symptoms from early to middle childhood.

Depressed individuals exhibit memory biases on the self-referent encoding task (SRET), such that those with depression exhibit poorer recall of positive, and enhanced recall of negative, trait adjectives (referred to as positive and negative processing biases). However, it is unclear when SRET biases emerge, whether they are stable, and if biases predict, or are predicted by, depressive symptoms. To address this, a community sample of 434 children completed the SRET and a depressive symptoms measure at ages 6 and 9. Negative and positive processing exhibited low, but significant, stability. At ages 6 and 9, depressive symptoms correlated with higher negative, and lower positive, SRET processing. Importantly, lower positive processing at age 6 predicted increased symptoms at age 9. However, negative processing at age 6 did not predict depressive symptoms at age 9, and depressive symptoms at age 6 did not predict SRET processing scores at age 9. This suggests that less positive processing may reflect vulnerability for future depressive symptoms

Extreme ultraviolet emission from non-relativistic electrons penetrating a multilayer nanostructure

The spectral and angular distributions from parametric X-radiation (PXR) from non-relativistic electrons penetrating a multilayer nanostructure are calculated while accounting for contributions of ordinary and diffracted transition radiationyesBelgorod State Universit

Are adults just big kids? Can the newer paediatric weight estimation systems be used in adults?

Background. The weight of a patient is an important variable that impacts on their medical care. Although some drugs are prescribed on a so-called ‘adult dose’ basis, we know that adults come in all shapes and sizes – a ‘one-dose-fits-all’ approach is not necessarily appropriate. As a measured weight may not always be available, an alternative method of accurately estimating weight is required.Objectives. To assess and compare the accuracy of weight estimations in adults by patient self-estimation, the Mercy method, Buckley method, Broca index and PAWPER XL-MAC (paediatric advanced weight prediction in the emergency room eXtra length/eXtra large mid-arm circumference) method.Methods. This was a prospective, cross-sectional study conducted at a tertiary academic hospital in a metropolitan area of Johannesburg, South Africa. Anthropometric variables of height, abdominal circumference, thigh circumference, mid-arm circumference and humeral length were measured. These variables were then applied to the various weight estimation methods and compared with the patient’s actual weight.Results. There were 188 adult patients included in the study. None of the methodologies evaluated in this study achieved the recommended >70% of weight estimations within 10% of the patient’s actual weight (PW10). The Mercy method was the closest to achieving greater than the recommended 95% for weight estimation falling within 20% of the patient’s actual weight (PW20). The PW20 for the Mercy method was 91.5%. The PAWPER XL-MAC and patient self-estimate methods achieved a PW20 of 85.1% and 86.1%, respectively. The Broca and Buckley methods performed poorly overall.Conclusions. None of the evaluated weight estimation methodologies was accurate enough for use in adult weight estimation. The Mercy and PAWPER XL-MAC methodologies both showed significant promise for use in adult weight estimation, but need further refinement. Although patient self-estimates were similarly accurate to those found in previous studies, they were not an accurate option; self-estimations would remain the first choice if the patient was able to provide such an estimation. The Broca index and Buckley method cannot be recommended owing to their poor performance