18 research outputs found

    A knowledge-based system for monitoring the electrical power system of the Hubble Space Telescope

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    The design and the prototype for the expert system for the Hubble Space Telescope's electrical power system are discussed. This prototype demonstrated the capability to use real time data from a 32k telemetry stream and to perform operational health and safety status monitoring, detect trends such as battery degradation, and detect anomalies such as solar array failures. This prototype, along with the pointing control system and data management system expert systems, forms the initial Telemetry Analysis for Lockheed Operated Spacecraft (TALOS) capability

    Caution, Student Experience May Vary: Social Identities Impact a Student's Experience in Peer Discussions

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    In response to calls for implementing active learning in college-level science, technology, engineering, and mathematics courses, classrooms across the country are being transformed from instructor centered to student centered. In these active-learning classrooms, the dynamics among students becomes increasingly important for understanding student experiences. In this study, we focus on the role a student prefers to assume during peer discussions, and how this preferred role may vary given a student's social identities. In addition we explore whether three hypothesized barriers to participation may help explain participation difference in the classroom. These barriers are 1) students are excluded from the discussion by actions of their groupmates; 2) students are anxious about participating in peer discussion; and 3) students do not see value in peer discussions. Our results indicate that self-reported preferred roles in peer discussions can be predicted by student gender, race/ethnicity, and nationality. In addition, we found evidence for all three barriers, although some barriers were more salient for certain students than others. We encourage instructors to consider structuring their in-class activities in ways that promote equity, which may require more purposeful attention to alleviating the current differential student experiences with peer discussions.National Science Foundation NSF DUE 1244847Science and Mathematics Educatio

    Measurement of the (eta c)(1S) production cross-section in proton-proton collisions via the decay (eta c)(1S) -> p(p)over-bar

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    SECURITY FOR DEVOPS DEPLOYMENT PROCESSES: DEFENSES, RISKS, RESEARCH DIRECTIONS

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    <p>DevOps is an emerging collection of software management practices intended to shorten time to market for new software features and to reduce the risk of costly deployment errors. In this paper we examine the security implications of two of the key DevOps practices, automation of the deployment pipeline using a deployment toolchain and infrastructure-as-code to specify the environment of the deployed software. We focus on identifying what changes when an organization moves from manual deployments to DevOps automated deployment processes. We reviewed the literature and conducted three case studies using simple configurations of common DevOps tools. This allowed us to identify specific: • Positive influences on security where automation enhances defenses. • Negative influences, where automation enables different kinds of attacks and increases the attack surface. • Research directions that look promising to support this new approach to software management. • Recommendations for DevOps adopters</p

    Article Gender Gaps in Achievement and Participation in Multiple Introductory Biology Classrooms

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    Although gender gaps have been a major concern in male-dominated science, technology, engi-neering, and mathematics disciplines such as physics and engineering, the numerical dominance of female students in biology has supported the assumption that gender disparities do not exist at the undergraduate level in life sciences. Using data from 23 large introductory biology classes for majors, we examine two measures of gender disparity in biology: academic achievement and participation in whole-class discussions. We found that females consistently underperform on exams compared with males with similar overall college grade point averages. In addition, although females on average represent 60 % of the students in these courses, their voices make up less than 40 % of those heard responding to instructor-posed questions to the class, one of the most common ways of engaging students in large lectures. Based on these data, we propose that, despite numerical dominance of females, gender disparities remain an issue in introductory biology classrooms. For student retention and achievement in biology to be truly merit based, we need to develop strategies to equalize the opportunities for students of different genders to practice the skills they need to excel

    Chemosensitization of Plasmodium falciparum by Probenecid In Vitro

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    Resistance to drugs can result from changes in drug transport, and this resistance can sometimes be overcome by a second drug that modifies the transport mechanisms of the cell. This strategy has been exploited to partly reverse resistance to chloroquine in Plasmodium falciparum. Studies with human tumor cells have shown that probenecid can reverse resistance to the antifolate methotrexate, but the potential for reversal of antifolate resistance has not been studied in P. falciparum. In the present study we tested the ability of probenecid to reverse antifolate resistance in P. falciparum in vitro. Probenecid, at concentrations that had no effect on parasite viability alone (50 μM), was shown to increase the sensitivity of a highly resistant parasite isolate to the antifolates pyrimethamine, sulfadoxine, chlorcycloguanil, and dapsone by seven-, five-, three-, and threefold, respectively. The equivalent effects against an antifolate-sensitive isolate were activity enhancements of approximately 3-, 6-, 1.2-, and 19-fold, respectively. Probenecid decreased the level of uptake of radiolabeled folic acid, suggesting a transport-based mechanism linked to folate salvage. When probenecid was tested with chloroquine, it chemosensitized the resistant isolate to chloroquine (i.e., enhanced the activity of chloroquine). This enhancement of activity was associated with increased levels of chloroquine accumulation. In conclusion, we have shown that probenecid can chemosensitize malaria parasites to antifolate compounds via a mechanism linked to reduced folate uptake. Notably, this effect is observed in both folate-sensitive and -resistant parasites. In contrast to the activities of antifolate compounds, the effect of probenecid on chloroquine sensitivity was selective for chloroquine-resistant parasites (patent P407595GB [W. P. Thompson & Co., Liverpool, United Kingdom] has been filed to protect this intellectual property)

    Activation of ERK in renal fibrosis after unilateral ureteral obstruction: Modulation by antioxidants

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    Background. A recent in vitro model of oxidative stress-induced renal fibrosis demonstrated that activated or phosphorylated extracellular signal-regulated protein kinase (PERK) played a role in apoptosis of renal fibroblasts, but not tubular epithelium where it promoted cell growth and survival. The present study utilized an in vivo model of renal fibrosis after unilateral ureteral obstruction (UUO) to examine the relationship between pERK, apoptosis, proliferation, and differentiation in renal fibroblast and tubular epithelial cells, in comparison with the in vitro results
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