An experimental model of a 2kw, 2500 volt power converter for ion thrustors using gate controlled switches in two phase-shifted parallel inverters summary report

Power converter for ion thrustors using electronic gate controlled switches in two phase-shifted parallel inverter

Standardised library instruction assessment: an institution-specific approach

Introduction We explore the use of a psychometric model for locally-relevant, information literacy assessment, using an online tool for standardised assessment of student learning during discipline-based library instruction sessions. Method A quantitative approach to data collection and analysis was used, employing standardised multiple-choice survey questions followed by individual, cognitive interviews with undergraduate students. The assessment tool was administered to five general education psychology classes during library instruction sessions. AnalysisDescriptive statistics were generated by the assessment tool. Results. The assessment tool proved a feasible means of measuring student learning. While student scores improved on every survey question, there was uneven improvement from pre-test to post-test for different questions. Conclusion Student scores showed more improvement for some learning outcomes over others, thus, spending time on fewer concepts during instruction sessions would enable more reliable evaluation of student learning. We recommend using digital learning objects that address basic research skills to enhance library instruction programmes. Future studies will explore different applications of the assessment tool, provide more detailed statistical analysis of the data and shed additional light on the significance of overall scores

Where joy resides: Four teacher educators evaluate themselves via multiple literacy artifacts and reflections

Through qualitative case studies, I explored what or who influenced four teacher educators to use multiple literacy artifacts and reflections to evaluate themselves, and help their students do the same. I define a wide range of print and non-print mediums as multiple literacies in that some learners rely on them to explore and express what they value as evaluators. Given that some students understand a poem or a social studies concept better when evaluate their interpretations through drama or drawing, as well as talk or writing, it is important for these students to be in classrooms where multiple avenues for evaluation are used. These opportunities, however, are rare. In order for teachers to learn to value the use of these literacies alongside print and talk as means of evaluation, teacher educators may need to experience them as potentially useful aspects of their own evaluation strategies. The four teacher educators I studied were Julie Brooks Pantano, Dan Rothermel, Jane Hansen, and myself. For my data, I collected and analyzed our artifacts and reflections, and observed, recorded, and analyzed our interactions during one semester of the Reading and Writing Seminar. I also observed in at least two sessions with one class which each of my colleagues taught, and I informally interviewed them and at least two of their students regarding what I observed and what they learned. I analyzed myself by studying my growth as a teacher educator and evaluator in tandem with my evolution as a sculptor. I designed a sculpture to show what I learned in this dissertation via a literacy beyond print, as well as print. I found that we were all influenced to value a wider range of literacies as evaluators through our participation in various diverse, supportive learning communities over time. In these communities, multiple literacies were explicitly valued, modeled, created in class, required, and shared by teachers and students alike in portfolio artifacts and reflections. As we evaluated ourselves, these literacies helped us find value in ourselves, others, and everyone\u27s growth in accord with what she or he valued as multifaceted persons in multiple social worlds

Nicotinic α7 acetylcholine receptor-mediated currents are not modulated by the tryptophan metabolite kynurenic acid in adult hippocampal interneurons

The  tryptophan  metabolite,  kynurenic  acid (KYNA),  is  classically  known  to  be  an antagonist  of ionotropic glutamate receptors. Within the last decade several reports have been published suggesting that KYNA also blocks nicotinic acetylcholine receptors (nAChRs) containing the α7 subunit (α7*). Most of these reports involve either indirect measurements of KYNA effects on α7 nAChR function, or are reports of KYNA effects in complicated in vivo systems.  However, a recent report investigating KYNA interactions with α7 nAChRs failed to detect an interaction using direct measurements of α7 nAChRs function.  Further, it showed that a KYNA blockade of α7 nAChR stimulated GABA release (an indirect measure of α7 nAChR function) was not due to KYNA blockade of the α7 nAChRs. The current study measured the direct effects of KYNA on α7-containing nAChRs expressed on interneurons in the hilar and CA1 stratum radiatum regions of the mouse hippocampus and on interneurons in the CA1 region of the rat hippocampus.  Here we show that KYNA does not block α7* nACHRs using direct patch-­clamp recording of α7 currents in adult brain slices

Identification of Florida Largemouth Bass Alleles in Arkansas Public and Private Aquaculture Ponds

The Florida subspecies of the largemouth bass (LMB) has often been introduced into waters outside of its range, with escape of individuals into associated waterways common. Sustaining pure lines within controlled hatchery settings is also difficult. The present study investigated LMB populations by way of allozyme analysis of three diagnostic loci of 115 LMB in three public and seven private aquaculture ponds within Arkansas. The goal was to determine the success of hatcheries in maintaining pure subspecies. None of the pond populations studied were fixed for all alleles. Private ponds had northern LMB allele frequencies of up to 0.40 in putative Florida LMB ponds. State fish hatcheries had higher proportions of predicted alleles. Most bass surveyed were intergrades (63%)

Low-Temperature Glassy Response of Ultrathin Manganite Films to Electric and Magnetic Fields

The glassy response of thin films of La0.8Ca0.2MnO3 to external magnetic and gated electrostatic fields in a field-effect geometry has been studied at low temperatures. A hierarchical response with irreversible memory effects, non-ergodic time evolution, aging and annealing behavior of the resistance suggest that the dynamics are governed by strain relaxation for both electronic and magnetic perturbations. Cross-coupling of charge, spin, and strain have been exploited to tune the coercivity of an ultrathin manganite film by electrostatic gating.Comment: 4 pages, 5 figure

Rapid antagonistic coevolution in an emerging pathogen and its vertebrate host

This is the final version of the article. Available from Elsevier via the DOI in this record.Host-pathogen coevolution is assumed to play a key role in eco-evolutionary processes, including epidemiological dynamics and the evolution of sexual reproduction [1-4]. Despite this, direct evidence for host-pathogen coevolution is exceptional [5-7], particularly in vertebrate hosts. Indeed, although vertebrate hosts have been shown to evolve in response to pathogens or vice versa [8-12], there is little evidence for the necessary reciprocal changes in the success of both antagonists over time [13]. Here, we generate a time-shift experiment to demonstrate adaptive, reciprocal changes in North American house finches (Haemorhous mexicanus) and their bacterial pathogen, Mycoplasma gallisepticum [14-16]. Our experimental design is made possible by the existence of disease-exposed and unexposed finch populations, which were known to exhibit equivalent responses to experimental inoculation until the recent spread of genetic resistance in the former [14, 17]. While inoculation with pathogen isolates from epidemic outbreak caused comparable sub-lethal eye-swelling in hosts from exposed (hereafter adapted) and unexposed (hereafter ancestral) populations, inoculation with isolates sampled after the spread of resistance were threefold more likely to cause lethal symptoms in hosts from ancestral populations. Similarly, the probability that pathogens successfully established an infection in the primary host and, before inducing death, transmitted to an uninfected sentinel was highest when recent isolates were inoculated in hosts from ancestral populations and lowest when early isolates were inoculated in hosts from adapted populations. Our results demonstrate antagonistic host-pathogen coevolution, with hosts and pathogens displaying increased resistance and virulence in response to each other over time.This research was supported by a Natural Environment Research Council standard grant to C.B. (NE/M00256X)