Antenna servo control system characterization: Rate loop analysis for 34-m antenna at DSS 15

The elevation and azimuth servo rate loops at the 34-m High Efficiency Deep Space Station 15 (DSS 15) are described. Time and frequency response performance criteria were measured. The results are compared to theoretically deduced performance criteria. Unexpected anomalies in the frequency response are observed and identified

Effect of sensitization on the stress corrosion cracking of AA5083

Stress corrosion cracking of AA5083 was evaluated using both slow strain rate testing, there was a strong effect of sensitization with aging time. Increasing aging time leads to a sharp decrease in strain to failure, as well as ultimate tensile strength (UTS). In the fully sensitized condition (175°C/240h) there was a significant effect of chloride concentration, with increasing chloride concentration leading to a sharp decrease in strain to failure and UTS. However, in the as received condition there was no significant effect of chloride concentration on the slow strain rate behavior. The difference in behavior is likely associated with continuous precipitation of β phase along the boundaries. Rising displacement tests were performed as a function of sensitization time and the Kth measured decreased sharply with aging time reaching ~4MPaÖm at 240h. The effect of chloride concentration and applied potential in the sensitized condition (175C/240h) was evaluated and the Kth decreased with increasing chloride concentration. At applied potentials below the breakdown potential of β there was an increase in the Kth but the values of Kth were not as those observed in the as received condition. The observations made suggest that the stress corrosion cracking of AA5083 was sensitive to the applied potential and chloride concentration which in turn control the crack tip conditions. The observed data were analyzed in terms of a crack tip strain rate model to quantify the behavior of AA5083

Spaceflight modulates gene expression in the whole blood of astronauts

Astronauts are exposed to a unique combination of stressors during spaceflight, which leads to alterations in their physiology and potentially increases their susceptibility to disease, including infectious diseases. To evaluate the potential impact of the spaceflight environment on the regulation of molecular pathways mediating cellular stress responses, we performed a first-of-its-kind pilot study to assess spaceflight-related gene-expression changes in the whole blood of astronauts. Using an array comprised of 234 well-characterized stress-response genes, we profiled transcriptomic changes in six astronauts (four men and two women) from blood preserved before and immediately following the spaceflight. Differentially regulated transcripts included those important for DNA repair, oxidative stress, and protein folding/degradation, including HSP90AB1, HSP27, GPX1, XRCC1, BAG-1, HHR23A, FAP48, and C-FOS. No gender-specific differences or relationship to number of missions flown was observed. This study provides a first assessment of transcriptomic changes occurring in the whole blood of astronauts in response to spaceflight

A CAT with caveats: is the Consensual Assessment Technique a reliable measure of graphic design creativity?

The Consensual Assessment Technique (CAT) is considered one of the gold standards for creativity assessment, and graphic design, arguably, is the most ubiquitous domain within the creative industries. For the first time, this study tests two tasks to measure graphic design creativity, and by extension, the reliability of the CAT as a measure of graphic design creativity. Initial research suggested the level of consensus amongst judges (often referred to as inter-rater reliability) was too low to be reliable, and may be unduly influenced by a judge’s preference for technical execution. In this study, 16 professional graphic designers were randomly assigned instructions to discount technical execution from creativity ratings, or given instruction that gave no stipulation, for 60 artworks. Inter-rater reliability scores were acceptable for each task and experimental condition, but were higher for judges that received instructions to discount technical execution. These and other results are discussed, and the argument presented that, for future CAT studies in this domain, specific instructions to discount technical execution offers a more reliable measure of graphic design creativity

The representation of scientific research in the national curriculum and secondary school pupils’ perceptions of research, its function, usefulness and value to their lives

Young people’s views on what research is, how it is conducted and whether it is important, influences the decisions they make about their further studies and career choices. In this paper we report the analysis of questionnaire data with a particular focus on pupil perceptions of research in the sciences and of the scientific method. The questionnaire was a 25-item Likert Scale (1-5) distributed to seven collaborating schools. We received 2634 returns from pupils across key stages 3, 4 and 5. We also asked teachers to complete the questionnaire in order to explore how they thought their pupils would respond. We received 54 teacher responses. Statistically significant differences in the responses were identified through a chi-square test on SPSS. As what is being taught influences secondary pupil views on research we also consider how the term ‘research’ appears in the national curriculum for England and Wales and the three main English exam boards. The main theoretical construct that informs our analysis of the questionnaire data and the national curriculum is Angela Brew’s 4-tier descriptor of perceptions of research (domino, trading, layer, journey). We use this framework in order to map what, when and how research is presented to school pupils in England and Wales. We also use this framework in order to highlight and discuss certain pupil views that emerged from the questionnaire data and which indicate areas where curriculum and pedagogy intervention may be necessary: pupils seem less confident in their understanding of research as involving the identification of a research question; and, they often see research as a means to confirm one’s own opinion. They do however understand research as involving the generation of new knowledge and the collection of new data, such as interviews and questionnaires as well as laboratory work, field trips and library searches and they appear relatively confident in their statements about their ability to do research, their school experiences of research and the importance of research in their future career choice

Racial Differences in Inequality Aversion: Evidence from Real World Respondents in the Ultimatum Game

The distinct historical and cultural experiences of American blacks and whites may influence whether members of those groups perceive a particular exchange as fair. We investigate racial differences in fairness standards using preferences for equal treatment in the ultimatum game, where responders choose to allow a proposed division of a monetary amount or to block it. Although previous research has studied group differences in the ultimatum game, no study has been able to examine these across races in America. We use a sample of over 1600 blacks and whites drawn from the universe of registered voters in three states and merged with information on neighborhood income and racial composition. We experimentally vary proposed divisions as well as the implied race of the ultimatum game proposer. We find no overall racial differences in acceptance rates or aversion to unequal divisions. However, we uncover racial differences in the response to pecuniary returns conditional on inequality of the division. This is driven by the lowest income group in our sample, which represents the 10th percentile of the black income distribution. The racial differences are robust across gender and age groups. We also find that blacks are more sensitive to unfair proposals from other blacks.

Reproducible computational biology experiments with SED-ML - The Simulation Experiment Description Markup Language

Background: The increasing use of computational simulation experiments to inform modern biological research creates new challenges to annotate, archive, share and reproduce such experiments. The recently published Minimum Information About a Simulation Experiment (MIASE) proposes a minimal set of information that should be provided to allow the reproduction of simulation experiments among users and software tools. Results: In this article, we present the Simulation Experiment Description Markup Language (SED-ML). SED-ML encodes in a computer-readable exchange format the information required by MIASE to enable reproduction of simulation experiments. It has been developed as a community project and it is defined in a detailed technical specification and additionally provides an XML schema. The version of SED-ML described in this publication is Level 1 Version 1. It covers the description of the most frequent type of simulation experiments in the area, namely time course simulations. SED-ML documents specify which models to use in an experiment, modifications to apply on the models before using them, which simulation procedures to run on each model, what analysis results to output, and how the results should be presented. These descriptions are independent of the underlying model implementation. SED-ML is a software-independent format for encoding the description of simulation experiments; it is not specific to particular simulation tools. Here, we demonstrate that with the growing software support for SED-ML we can effectively exchange executable simulation descriptions. Conclusions: With SED-ML, software can exchange simulation experiment descriptions, enabling the validation and reuse of simulation experiments in different tools. Authors of papers reporting simulation experiments can make their simulation protocols available for other scientists to reproduce the results. Because SED-ML is agnostic about exact modeling language(s) used, experiments covering models from different fields of research can be accurately described and combined

Molecular evolution of urea amidolyase and urea carboxylase in fungi

Background: Urea amidolyase breaks down urea into ammonia and carbon dioxide in a two-step process, while another enzyme, urease, does this in a one step-process. Urea amidolyase has been found only in some fungal species among eukaryotes. It contains two major domains: the amidase and urea carboxylase domains. A shorter form of urea amidolyase is known as urea carboxylase and has no amidase domain. Eukaryotic urea carboxylase has been found only in several fungal species and green algae. In order to elucidate the evolutionary origin of urea amidolyase and urea carboxylase, we studied the distribution of urea amidolyase, urea carboxylase, as well as other proteins including urease, across kingdoms. Results: Among the 64 fungal species we examined, only those in two Ascomycota classes (Sordariomycetes and Saccharomycetes) had the urea amidolyase sequences. Urea carboxylase was found in many but not all of the species in the phylum Basidiomycota and in the subphylum Pezizomycotina (phylum Ascomycota). It was completely absent from the class Saccharomycetes (phylum Ascomycota; subphylum Saccharomycotina). Four Sordariomycetes species we examined had both the urea carboxylase and the urea amidolyase sequences. Phylogenetic analysis showed that these two enzymes appeared to have gone through independent evolution since their bacterial origin. The amidase domain and the urea carboxylase domain sequences from fungal urea amidolyases clustered strongly together with the amidase and urea carboxylase sequences, respectively, from a small number of beta- and gammaproteobacteria. On the other hand, fungal urea carboxylase proteins clustered together with another copy of urea carboxylases distributed broadly among bacteria. The urease proteins were found in all the fungal species examined except for those of the subphylum Saccharomycotina. Conclusions: We conclude that the urea amidolyase genes currently found only in fungi are the results of a horizontal gene transfer event from beta-, gamma-, or related species of proteobacteria. The event took place before the divergence of the subphyla Pezizomycotina and Saccharomycotina but after the divergence of the subphylum Taphrinomycotina. Urea carboxylase genes currently found in fungi and other limited organisms were also likely derived from another ancestral gene in bacteria. Our study presented another important example showing plastic and opportunistic genome evolution in bacteria and fungi and their evolutionary interplay

Potholes and molehills: bias in the diagnostic performance of diffusion-tensor imaging in concussion

PURPOSE: To investigate the extent of bias in a clinical study involving pothole analysis of diffusion-tensor imaging (DTI) data used to quantify white matter lesion load in diseases with a heterogeneous spatial distribution of pathologic findings, such as mild traumatic brain injury (TBI), and create a mathematical model of the bias. MATERIALS AND METHODS: Use of the same reference population to define normal findings and make comparisons with a patient group introduces bias, which potentially inflates reported diagnostic performance. In this institutional review board-approved prospective observational cohort study, DTI data were obtained in 20 patients admitted to the emergency department with mild TBI and in 16 control subjects. Potholes and molehills were defined as clusters of voxels with fractional anisotropy values more than 2 standard deviations below and above the mean of the corresponding voxels in the reference population, respectively. The number and volume of potholes and molehills in the two groups were compared by using a Mann-Whitney U test. RESULTS: Standard analysis showed significantly more potholes in mild TBI than in the control group (102.5 +/- 34.3 vs 50.6 +/- 28.9, P \u3c .001). Repeat analysis by using leave-one-out cross-validation decreased the apparent difference in potholes between groups (mild TBI group, 102.5 +/- 34.3; control group, 93.4 +/- 27.2; P = .369). It was demonstrated that even with 100 subjects, this bias can decrease the voxelwise false-positive rate by more than 30% in the control group. CONCLUSION: The pothole approach to neuroimaging data may introduce bias, which can be minimized by independent training and test groups or cross-validation methods. This bias is sufficient to call into question the previously reported diagnostic performance of DTI for mild TBI

Effect of Polyethylene Glycol 3350 on the Handling Properties of Low Salt Wheat Dough Formulations

The effect of polyethylene glycol (PEG) 3350 addition (3%, flour wt. basis) on the properties of dough made from two Canadian Western Red Spring wheat cultivars (Triticum aestivum L. ‘Harvest’ and ‘Pembina’) differing in dough mixing requirements and dough-handling properties was investigated in a low salt dough formulation (1% NaCl, flour wt. basis). PEG was added for experimental purposes to alter water mobility to better understand underlining mechanisms, however would not be used in real bread formulations. For cultivar Harvest, but not Pembina, dough stickiness was reduced by the addition of PEG. Dough freezable water content decreased with the addition of PEG for both cultivars. Rheological measurements showed that PEG increased dough stiffness as measured by the complex modulus |G*|. Creep measurements indicated that the relative elastic component (Jel) increased whereas maximum deformation (Jmax) decreased with the addition of PEG for cultivar Harvest only. Dough made with a weaker cultivar (Harvest) with the addition of PEG performed similarly to dough made with a stronger cultivar (Pembina) without PEG. Results indicate that in a low sodium environment, availability of water is critically important for controlling a number of properties that relate closely to dough machinability, especially in a weaker wheat cultivar