261 research outputs found

    The Rotation Velocity - Density Relation

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    We have assembled 21-cm linewidths for 376 of the 732 galaxies in a magnitude-limited redshift survey of the the Perseus-Pisces region. We analyze a distance limited subset of 271 galaxies (131 widths) to examine the relationship between linewidth and local density. The sample indicates that galaxies with linewidths ≳480\gtrsim 480 km/s are absent from regions where the galaxy density is ≲0.03\lesssim 0.03 galaxies Mpc−3^{-3} (MB(0)<−18.3M_{B(0)}< -18.3). This effect is in the direction predicted by standard CDM models. Galaxies with linewidths ≲\lesssim 480 km/s appear throughout the sample. The observational constraints could be substantially improved with a larger sample, IR photometry, and more uniform 21-cm data.Comment: 11 pages, 9 postscript figures; to appear in July 1996 A

    Building an Academic Community SmallSat Program

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    The US Coast Guard Academy (CGA), which educates future officers for service in the US Coast Guard, is developing a multifaceted program in SmallSats. The CGA space initiative includes undergraduate courses, such as a recently-created Remote Sensing course. It incorporates Virginia Space\u27s ThinSat Educational Program, providing hands-on experience in designing, building, and testing miniature satellites through space mission engineering; this involves collaboration between Science and Engineering and is extended to local high schools through their participation in SmallSat projects with CGA faculty and students. An important addition to the CGA space initiative is an MC3 ground station atop the Science Department building at CGA. It will be used to train cadets in satellite operations and ground station hardware, and to acquire data from satellites, allowing for training in cyber security and data analysis, and for use in student and faculty research projects. Sequential year-long senior student capstone projects in the Engineering Department to design, build, and test CubeSats, including new components and innovations, have already begun and will continue. Additional capstone projects involving CubeSats sensors, the use of UAVs, and remote sensing data analysis, including data from the CGA ground station, are planned in the Science Department with the 2020 implementation of a revised Science major

    SmallSat Platform Development for Coast Guard Academy Collaborative Space-Based Research

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    Collaborations utilizing small spacecraft in near earth orbit between the U. S. Coast Guard Academy (CGA), Naval Research Lab (NRL), the U. S. Naval Academy (USNA), and the Air Force Institute of Technology (AFIT) have initiated scientific and engineering space-based experiments. Sourced opportunities like the VaSpace ThinSat missions have provided a platform for payload, sensor, and experiment development that would have otherwise been resource prohibitive. We have constructed an impedance probe payload for launch in Fall 2020 derived from the existing ‘Space PlasmA Diagnostic suitE’ (SPADE) mission operating from NASA’s International Space Station. Currently both space and laboratory plasmas are investigated with AC impedance measurements using a radio frequency antenna. Plasma electron density data collected from the ThinSat will however use an innovative surface-mounted dipole antenna to gather the required sheath-plasma and plasma resonance information. On that same launch, a compact multispectral ‘Pixel Sensor’ with a 450 nm – 1000 nm spectral range will add to the existing Inertial Motion Unit, Temperature Sensor, Infrared Sensor, and Energetic Particle Detector baselined in previous launches. Our engineering team has begun to design, build, and test a solar panel deployment and de-orbiting mechanism for a CubeSat with the USNA’s Aerospace Engineering Department that utilizes a miniature motor for deployment actuation. For the motor to produce the required torque, a gear ratio of 20:1 is necessary. Impedance probe optimization, de-orbiting mechanism automation, and data collection obstacles, solutions, and procedures will be reported

    Using Satellite Aerosol Retrievals to Monitor Surface Particulate Air Quality

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    The MODIS and MISR aerosol products were designed nearly two decades ago for the purpose of climate applications. Since launch of Terra in 1999, these two sensors have provided global, quantitative information about column-integrated aerosol properties, including aerosol optical depth (AOD) and relative aerosol type parameters (such as Angstrom exponent). Although primarily designed for climate, the air quality (AQ) community quickly recognized that passive satellite products could be used for particulate air quality monitoring and forecasting. However, AOD and particulate matter (PM) concentrations have different units, and represent aerosol conditions in different layers of the atmosphere. Also, due to low visible contrast over brighter surface conditions, satellite-derived aerosol retrievals tend to have larger uncertainty in urban or populated regions. Nonetheless, the AQ community has made significant progress in relating column-integrated AOD at ambient relative humidity (RH) to surface PM concentrations at dried RH. Knowledge of aerosol optical and microphysical properties, ambient meteorological conditions, and especially vertical profile, are critical for physically relating AOD and PM. To make urban-scale maps of PM, we also must account for spatial variability. Since surface PM may vary on a finer spatial scale than the resolution of standard MODIS (10 km) and MISR (17km) products, we test higher-resolution versions of MODIS (3km) and MISR (1km research mode) retrievals. The recent (July 2011) DISCOVER-AQ campaign in the mid-Atlantic offers a comprehensive network of sun photometers (DRAGON) and other data that we use for validating the higher resolution satellite data. In the future, we expect that the wealth of aircraft and ground-based measurements, collected during DISCOVER-AQ, will help us quantitatively link remote sensed and ground-based measurements in the urban region

    Report on the Third Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE3)

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    This report records and discusses the Third Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE3). The report includes a description of the keynote presentation of the workshop, which served as an overview of sustainable scientific software. It also summarizes a set of lightning talks in which speakers highlighted to-the-point lessons and challenges pertaining to sustaining scientific software. The final and main contribution of the report is a summary of the discussions, future steps, and future organization for a set of self-organized working groups on topics including developing pathways to funding scientific software; constructing useful common metrics for crediting software stakeholders; identifying principles for sustainable software engineering design; reaching out to research software organizations around the world; and building communities for software sustainability. For each group, we include a point of contact and a landing page that can be used by those who want to join that group's future activities. The main challenge left by the workshop is to see if the groups will execute these activities that they have scheduled, and how the WSSSPE community can encourage this to happen

    A consideration of the challenges involved in supervising international masters students

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    This paper explores the challenges facing supervisors of international postgraduate students at the dissertation stage of the masters programme. The central problems of time pressure, language difficulties, a lack of critical analysis and a prevalence of personal problems among international students are discussed. This paper makes recommendations for the improvement of language and critical thinking skills, and questions the future policy of language requirements at HE for international Masters students

    Joining the conspiracy? Negotiating ethics and emotions in researching (around) AIDS in southern Africa

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    AIDS is an emotive subject, particularly in southern Africa. Among those who have been directly affected by the disease, or who perceive themselves to be personally at risk, talking about AIDS inevitably arouses strong emotions - amongst them fear, distress, loss and anger. Conventionally, human geography research has avoided engagement with such emotions. Although the ideal of the detached observer has been roundly critiqued, the emphasis in methodological literature on 'doing no harm' has led even qualitative researchers to avoid difficult emotional encounters. Nonetheless, research is inevitably shaped by emotions, not least those of the researchers themselves. In this paper, we examine the role of emotions in the research process through our experiences of researching the lives of 'Young AIDS migrants' in Malawi and Lesotho. We explore how the context of the research gave rise to the production of particular emotions, and how, in response, we shaped the research, presenting a research agenda focused more on migration than AIDS. This example reveals a tension between universalised ethics expressed through ethical research guidelines that demand informed consent, and ethics of care, sensitive to emotional context. It also demonstrates how dualistic distinctions between reason and emotion, justice and care, global and local are unhelpful in interpreting the ethics of research practice

    Report on the Third Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE3)

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    This report records and discusses the Third Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE3). The report includes a description of the keynote presentation of the workshop, which served as an overview of sustainable scientific software. It also summarizes a set of lightning talks in which speakers highlighted to-the-point lessons and challenges pertaining to sustaining scientific software. The final and main contribution of the report is a summary of the discussions, future steps, and future organization for a set of self-organized working groups on topics including developing pathways to funding scientific software; constructing useful common metrics for crediting software stakeholders; identifying principles for sustainable software engineering design; reaching out to research software organizations around the world; and building communities for software sustainability. For each group, we include a point of contact and a landing page that can be used by those who want to join that group’s future activities. The main challenge left by the workshop is to see if the groups will execute these activities that they have scheduled, and how the WSSSPE community can encourage this to happe

    Safety and Reactogenicity of an MSP-1 Malaria Vaccine Candidate: A Randomized Phase Ib Dose-Escalation Trial in Kenyan Children

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    OBJECTIVE: Our aim was to evaluate the safety, reactogenicity, and immunogenicity of an investigational malaria vaccine. DESIGN: This was an age-stratified phase Ib, double-blind, randomized, controlled, dose-escalation trial. Children were recruited into one of three cohorts (dosage groups) and randomized in 2:1 fashion to receive either the test product or a comparator. SETTING: The study was conducted in a rural population in Kombewa Division, western Kenya. PARTICIPANTS: Subjects were 135 children, aged 12–47 mo. INTERVENTIONS: Subjects received 10, 25, or 50 μg of falciparum malaria protein 1 (FMP1) formulated in 100, 250, and 500 μL, respectively, of AS02A, or they received a comparator (Imovax® rabies vaccine). OUTCOME MEASURES: We performed safety and reactogenicity parameters and assessment of adverse events during solicited (7 d) and unsolicited (30 d) periods after each vaccination. Serious adverse events were monitored for 6 mo after the last vaccination. RESULTS: Both vaccines were safe and well tolerated. FMP1/AS02A recipients experienced significantly more pain and injection-site swelling with a dose-effect relationship. Systemic reactogenicity was low at all dose levels. Hemoglobin levels remained stable and similar across arms. Baseline geometric mean titers were comparable in all groups. Anti-FMP1 antibody titers increased in a dose-dependent manner in subjects receiving FMP1/AS02A; no increase in anti-FMP1 titers occurred in subjects who received the comparator. By study end, subjects who received either 25 or 50 μg of FMP1 had similar antibody levels, which remained significantly higher than that of those who received the comparator or 10 μg of FMP1. A longitudinal mixed effects model showed a statistically significant effect of dosage level on immune response (F(3,1047) = 10.78, or F(3, 995) = 11.22, p < 0.001); however, the comparison of 25 μg and 50 μg recipients indicated no significant difference (F(1,1047) = 0.05; p = 0.82). CONCLUSIONS: The FMP1/AS02A vaccine was safe and immunogenic in malaria-exposed 12- to 47-mo-old children and the magnitude of immune response of the 25 and 50 μg doses was superior to that of the 10 μg dose

    Report on the 3rd Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE3)

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    This report records and discusses the Third Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE3). The report includes a description of the keynote presentation of the workshop, which served as an overview of sustainable scientific software. It also summarizes a set of lightning talks in which speakers highlighted to-the-point lessons and challenges pertaining to sustaining scientific software. The final and main contribution of the report is a summary of the discussions, future steps, and future organization for a set of self-organized working groups on topics including developing pathways to funding scientific software; constructing useful common metrics for crediting software stakeholders; identifying principles for sustainable software engineering design; reaching out to research software organizations around the world; and building communities for software sustainability. For each group, we include a point of contact and a landing page that can be used by those who want to join that group's future activities. The main challenge left by the workshop is to see if the groups will execute these activities that they have scheduled, and how the WSSSPE community can encourage this to happen
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