High-field magnetoresistance of Fe/GaAs/Fe tunnel junctions

We investigate transport through 6 to 10 nm thin epitaxial GaAs(001) barriers sandwiched between polycrystalline iron films. Apart from a pronounced tunneling magnetoresistance effect (TMR) at low magnetic fields we observe a distinct negative magnetoresistance (MR) at low and a positive MR at higher temperatures. We show that the negative MR contribution is only observed for the ferromagnetic iron contacts but is absent if iron is replaced by copper or gold electrodes. Possible explanations of the negative MR involve suppression of spin-flip scattering or Zeeman splitting of the tunneling barrier.Comment: 12 pages, 4 figures, submitted to Appl. Phys. Let

THE PROBLEM OF MEASURING THE ABSOLUTE YIELD OF 14-Mev NEUTRONS BY MEANS OF AN ALPHA COUNTER

The assumptions used to derive the total neutron yield per detected alpha particle (from the D-T reaction) which were derived in an earlier report are reexamined in the light of additional experimental information. It is concluded that for an alpha counter at 90 deg to the incident beam direction the assumptions introduce practically no difficulties. Therefore, for precise monitoring in the absence of certain target information it is recommended that this configuration be used. For counters at angles different from 90 deg , nonuniformity of target loading contributes the most serious error to the computed yield. (auth

Classification Strategy to Identify and Classify Common Cracks in Green-State Powdered Metallurgy Compacts

The presence of and/or the potential for cracks in powder metallurgy components is an industry recognized quality concern. In an industry wide survey, eliminating or controlling of cracks was found to be the second most important research priority identified [1]. The general improvement of mechanical properties was the number one issue identified. It should be noted, however, that the benefits of material properties gains only slightly exceeded that of the cracking issue in importance to the industry respondents of the surveys

Metallicity determination in gas-rich galaxies with semiempirical methods

A study of the precision of the semiempirical methods used in the determination of the chemical abundances in gas-rich galaxies is carried out. In order to do this the oxygen abundances of a total of 438 galaxies were determined using the electronic temperature, the $R_{23}$ and the P methods. The new calibration of the P method gives the smaller dispersion for the low and high metallicity regions, while the best numbers in the turnaround region are given by the $R_{23}$ method. We also found that the dispersion correlates with the metallicity. Finally, it can be said that all the semiempirical methods studied here are quite insensitive to metallicity with a value of $8.0\pm0.2$ dex for more than 50% of the total sample. \keywords{ISM: abundances; (ISM): H {\sc ii} regions}Comment: 26 pages, 9 figures and 2 tables. To appear at AJ, January 200

Efficient cosmological parameter sampling using sparse grids

We present a novel method to significantly speed up cosmological parameter sampling. The method relies on constructing an interpolation of the CMB-log-likelihood based on sparse grids, which is used as a shortcut for the likelihood-evaluation. We obtain excellent results over a large region in parameter space, comprising about 25 log-likelihoods around the peak, and we reproduce the one-dimensional projections of the likelihood almost perfectly. In speed and accuracy, our technique is competitive to existing approaches to accelerate parameter estimation based on polynomial interpolation or neural networks, while having some advantages over them. In our method, there is no danger of creating unphysical wiggles as it can be the case for polynomial fits of a high degree. Furthermore, we do not require a long training time as for neural networks, but the construction of the interpolation is determined by the time it takes to evaluate the likelihood at the sampling points, which can be parallelised to an arbitrary degree. Our approach is completely general, and it can adaptively exploit the properties of the underlying function. We can thus apply it to any problem where an accurate interpolation of a function is needed.Comment: Submitted to MNRAS, 13 pages, 13 figure

Signatures of Adaptation and Acclimatization to Reef Flat and Slope Habitats in the Coral Pocillopora damicornis

Strong population-by-habitat interactions across environmental gradients arise from genetic adaptation or acclimatization and represents phenotypic variation required for populations to respond to changing environmental conditions. As such, patterns of adaptation and acclimatization of reef-building corals are integral to predictions of the future of coral reefs under climate warming. The common brooding coral, Pocillopora damicornis, exhibits extensive differences in host genetic and microbial symbiont community composition between depth habitats at Heron Island in the southern Great Barrier Reef, Australia. An 18-month reciprocal field transplant experiment was undertaken to examine the environmental and genetic drivers behind variation in survival, weight gain, heat tolerance and algal symbiont community between the reef flat and slope habitats. We observed population-by-habitat interactions for in situ partial mortality and weight gain, where trait-related fitness of natives was greater than transplants in most cases, consistent with local adaptation. On average, flat colonies transplanted to the slope had a relatively low partial mortality but minimal weight gain, whereas slope colonies transplanted to the flat had relatively high partial mortality and average weight gain. Experimental heat tolerance was always higher in colonies sourced from the flat, but increased when slope colonies were transplanted to the flat, providing evidence of acclimatization in these colonies. The performance of certain slope to flat transplants may have been driven by each colony’s algal symbiont (Symbiodiniaceae) community, and flat variants were observed in a small number of slope colonies that either had a fixed flat composition before transplantation or shuffled after transplantation. Host genotypes of previously identified genetic outlier loci could not predict survival following transplantation, possibly because of low sample size and/or polygenic basis to the traits examined. Local environmental conditions and Symbiodiniaceae composition may provide insight into the adaptive potential to changing environmental conditions

Identification of novel oyster allergens using a combined transcriptomic and proteomic approach for improved component resolved diagnosis

Background: Increasing production and consumption of mollusc is associated with the rise in prevalence of mollusc allergy worldwide, currently ranging from 0.15% to 1.3% of the general population. However, the elucidation of mollusc allergens for better diagnostics still lags behind other seafood groups such as fish and crustacean. Genomic data have been utilized previously for improved identification of non-food allergens by performing similarity searching using the BLAST program. Based on the published genome of the Pacific oyster (Crassostrea gigas) we aimed to identify the complete potential oyster allergen repertoire using ioinformatics analysis, and to investigate identified protein allergenicity using a combination of immuno-chemical methods and proteomic analysis. Results: Ninety-five potential allergenic proteins of the Pacific oyster were discovered using in silico analyses. These proteins were of same protein family and had more than 50% amino acid identity with their homologous allergens. The allergenicity of these proteins was characterized using a combination of immunoassay and transcriptome-derived proteomics analyses. However The 2D-immunoblotting results showed only twenty two IgE-reactive spots in the raw extract of the Pacific oyster, and six spots in the heated extract. The identity of these IgE-reactive proteins was investigated by mass spectrometry. Sixteen allergens were identified, some with two or more isoforms. Conclusions: The combination of genomics coupled to proteomics and IgE-reactivity profiling is a powerful method for the identification of novel allergens from food sources. Using this combination approach we were able to expand the current knowledge on IgE-reactivity to various proteins of the Pacific oyster. These newly identified allergens and knowledge of their gene sequences will facilitate the development of improved component resolved diagnosis and future immunotherapy approach for oyster allergy

The Resilient Organization: A Meta-Analysis of the Effect of Communication on Team Diversity and Team Performance

The Input-Process-Output framework is adopted to examine the impact of diversity attributes (the input) on communication (the process) and their influence on performance (the output), to understand the internal group/team working mechanisms of organizational resilience. A meta-analysis of 174 correlations from 35 empirical studies undertaken over 35 years (1982-2017) showed that members of a team who have different experiences are more likely to share information and communicate openly when they deal with a task that requires collaboration outside the team. This supports the view that organizations are more resilient by being more closely connected with the external environment. Differences in social categories tend to favor openness of communication, especially in the case of age diversity and race/ethnicity diversity. An increase in openness of communication is likely to enhance team performance, particularly for small and medium sized teams operating in manufacturing industries, while frequency of communication can be beneficial for both large and medium sized teams working in the high technology industry. The positive workings of these associations form the resilient organization

Bipolar spintronics: From spin injection to spin-controlled logic

An impressive success of spintronic applications has been typically realized in metal-based structures which utilize magnetoresistive effects for substantial improvements in the performance of computer hard drives and magnetic random access memories. Correspondingly, the theoretical understanding of spin-polarized transport is usually limited to a metallic regime in a linear response, which, while providing a good description for data storage and magnetic memory devices, is not sufficient for signal processing and digital logic. In contrast, much less is known about possible applications of semiconductor-based spintronics and spin-polarized transport in related structures which could utilize strong intrinsic nonlinearities in current-voltage characteristics to implement spin-based logic. Here we discuss the challenges for realizing a particular class of structures in semiconductor spintronics: our proposal for bipolar spintronic devices in which carriers of both polarities (electrons and holes) contribute to spin-charge coupling. We formulate the theoretical framework for bipolar spin-polarized transport, and describe several novel effects in two- and three-terminal structures which arise from the interplay between nonequilibrium spin and equilibrium magnetization.Comment: 16 pages, 7 figure

Unlocking Women's Leadership Potential: A Curricular Example for Developing Female Leaders in Academia

Women in academia face unique challenges when it comes to advancing to professorship. Using latest research about gender and academic leadership, we present a training curriculum that is sensitive to the unique demands of women in and aspiring to leadership positions in academia. The context-specific and evidence-based approach and a focus on self-directed leadership development are unique characteristics of the training. It aims to enhance women's motivation to lead, increase their knowledge about academic leadership, and empower them to seek the support they need to proactively work toward appointment to a professorship. We also delineate an evaluation framework, which addresses these targeted outcomes. The findings from a pilot program in Germany confirmed that the curriculum is effective in developing women as academic leaders. The discussion highlights the significance of a context-specific and evidence-based approach to women's leadership development in academia