118 research outputs found

    Solar array conceptual design for the Halley's Comet ion drive mission, phase 2

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    Conceptual design studies were performed directed toward a high power, ultralightweight solar array, compatible with the requirements for the Halley's Comet Ion Drive Mission. A planar, rollup array design concept capable of producing 120 kW at 1 AU and 6 kW at 4.5 AU, and a concentrator, rollup array design concept capable of producing 60 kW at 1 AU and 15.5 kW at 4.5 AU evolved. Both arrays make maximum use of thin film, lightweight technology. The Halley's Comet spacecraft and mission requirements developed from preliminary definition to a more finalized and mature design. As solar array requirements were updated, conceptual design iterations were necessary to keep pace with the rapidly changing program objectives and goals. The Halley's Comet Mission program status and design approaches were reviewed and more realistic power requirements at 4.5 AU for the ion engines were established at the 12 to 16 kW range. This higher power necessitated a change from the planar array design to a concentrator array design in order to remain within suitable cost and weight objectives

    Water Markets and Climate Change Adaptation: Assessing the Water Trading Experiences of Chile, Australia, and the U.S. with Respect to Climate Pressures on Water Resources

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    Water trading and water markets have been listed by leading climate change organizations as a possible tool for climate change adaptation. Experience with water trading exists in many places in the world, and three of the most well-known and widely-studied markets for water rights are found in the Western United States, Chile, and Australia\u27s Murray-Darling Basin. While the body of literature on the performance of these markets is extensive, few papers relate the experiences of these three countries to adaptation as of yet. This thesis seeks to report on the outcomes of water markets in three cases with special attention to the following adaptation questions: Can water markets be a tool to address increasing variability in water supply; and what are the necessary environmental, political, and historic conditions for a market to be successful in allocating water resources under situations of scarcity? The experiences of these three cases yield the following conclusions about the use of water markets in climate change adaptation: the degree of existing infrastructure for water storage and transportation must be considered in the implementation of markets; water markets must be continually revised to internalize local third party effects; transaction costs must be minimized if markets are to serve increased short-term variability in water supply; sustainable outcomes are most readily met when markets approximate “cap-and-trade” programs; and the involvement of local institutions in market design will support market activity and the achievement of localized adaptation goals

    Conceptual approach study of a 200 watt per kilogram solar array, phase 1

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    Two alternative designs were studied; one a retractable rollout design and the other a nonretractable foldout configuration. An end of life (EOL) power for either design of 0.79 beginning of life (BOL) is predicted based on one solar flare during a 3 year interplanetary mission. Both array configurations incorporate the features of flexible substrates and cover sheets. A power capacity of 10 kilowatt is achieved in a blanket area of 76 sq m with an area utilization factor of 0.8. A single array consists of two identical solar cell blankets deployed concurrently by a single, coilable longeron boom. An out of plane angle of 8-1/4 deg is maintained between the two blankets so that the inherent inplane stiffness of the blankets may be used to obtain out of plane stiffness. This V-stiffened design results in a 67% reduction in the stiffness requirement for the boom. Since boom mass scales with stiffness, a lower requirement on boom stiffness results in a lower mass for the boom. These solar arrays are designed to be compatible with the shuttle launch environment and shuttle cargo bay size limitations

    Acute angle closure glaucoma precipitated by homeopathic eyedrops containing Atropa belladonna.

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    Acute angle closure glaucoma is a sight-threatening condition that may lead to blindness. This is a case report of a woman who presented to the emergency department (ED) with acute angle closure glaucoma following use of an over-the-counter (OTC) homeopathic eye drop containing atropa belladonna (deadly nightshade). A 55-year-old woman presented to the ED with a 5-day history of left eye redness, swelling, tearing, and foreign-body sensation that had acutely worsened in the last two days. Her exam revealed mild left conjunctival injection with watery tearing and a hazy appearance of her left cornea. Fluorescein staining was negative, while tonometry revealed elevated intraocular pressure on the left, suggestive of acute angle closure glaucoma. She was urgently referred to ophthalmology. The etiology of the acute angle closure glaucoma was initially unclear however, with additional prompting, she revealed that two days prior she had started using homeopathic OTC eye drops. Inspection of the eyedrop\u27s ingredients revealed that atropa belladonna was the primary ingredient and likely precipitated her isolated episode of acute angle closure glaucoma. A high level of clinical suspicion and focused ophthalmic exam including tonometry is essential to identify acute angle closure glaucoma in the ED. We present a case report of acute angle closure glaucoma associated with the use of homeopathic belladonna-containing eyedrops. Our report reinforces the necessity to perform thorough medication and supplement history given the prevalence of physiologically active substances available in OTC medications

    VISUALIZING THE DATA VISUALIZATION NETWORK: THE DVMAP PROJECT

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    Data visualization is a familiar buzzword. Experts in the humanities, social and natural sciences, as well as technology, along with semi-experts and the general public, reach people everywhere with trends and conclusions drawn from visualized data. Governments, industries, businesses, sciences, marketers, academics, students and others value data visualization methods and tools as critical, applicable tools for understanding the world, which provide rich information analyses for specialists and generalists alike. Unfortunately, no single resource offers a space where people working in the multifaceted field of data visualization can share projects they are working on, tools they created, educational opportunities in the field, nor where they (and their work) are situated geographically. A research group at New Mexico Institute of Mining and Technology seeks to fill this gap with a repository of data visualization resources called ―Data Visualization Map (DVMap).‖ The DVMap is an interactive network data and geographic representation graph that provides a data visualization space for people across the world to share, view and/or collaborate on projects and publications; tools deployed or under development; educational opportunities in data visualization, such as formal programs, summer seminars, conferences; and the geographical locations of the users, projects, tools and educational opportunities. Given the necessity of this repository, this paper outlines the structure, underlying methodology, and anticipated outcomes for the DVMap data visualization network. The paper also accounts for limitations of the project and the potential problems of creating a map that wants to share work – especially work in progress – with everyone

    Understanding the pathways from biodiversity to agro-ecological outcomes: A new, interactive approach

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    The adoption of agro-ecological practices in agricultural systems worldwide can contribute to increased food production without compromising future food security, especially under the current biodiversity loss and climate change scenarios. Despite the increase in publications on agro-ecological research and practices during the last 35 years, a weak link between that knowledge and changed farmer practices has led to few examples of agro-ecological protocols and effective delivery systems to agriculturalists. In an attempt to reduce this gap, we synthesised the main concepts related to biodiversity and its functions by creating a web-based interactive spiral (www.biodiversityfunction.com). This tool explains and describes a pathway for achieving agro-ecological outcomes, starting from the basic principle of biodiversity and its functions to enhanced biodiversity on farms. Within this pathway, 11 key steps are identified and sequentially presented on a web platform through which key players (farmers, farmer networks, policy makers, scientists and other stakeholders) can navigate and learn. Because in many areas of the world the necessary knowledge needed for achieving the adoption of particular agro-ecological techniques is not available, the spiral approach can provide the necessary conceptual steps needed for obtaining and understanding such knowledge by navigating through the interactive pathway. This novel approach aims to improve our understanding of the sequence from the concept of biodiversity to harnessing its power to improve prospects for ‘sustainable intensification’ of agricultural systems worldwide

    Breech presentation at term and associated obstetric risks factors-a nationwide population based cohort study

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    Purpose The aim of this study was to estimate whether breech presentation at term was associated with known individual obstetric risk factors for adverse fetal outcome. Methods This was a retrospective, nationwide Finnish population-based cohort study. Obstetric risks in all breech and vertex singleton deliveries at term were compared between the years 2005 and 2014. A multivariable logistic regression model was used to determine significant risk factors. Results The breech presentation rate at term for singleton pregnancies was 2.4%. The stillbirth rate in term breech presentation was significantly higher compared to cephalic presentation (0.2 vs 0.1%). The odds ratios (95% CIs) for fetal growth restriction, oligohydramnios, gestational diabetes, a history of cesarean section and congenital fetal abnormalities were 1.19 CI (1.07-1.32), 1.42 CI (1.27-1.57), 1.06 CI (1.00-1.13), 2.13 (1.98-2.29) and 2.01 CI (1.92-2.11). Conclusions The study showed that breech presentation at term on its own was significantly associated with antenatal stillbirth and a number of individual obstetric risk factors for adverse perinatal outcomes. The risk factors included oligohydramnios, fetal growth restriction, gestational diabetes, history of caesarean section and congenital anomalies.Peer reviewe

    Kuhnian revolutions in neuroscience: the role of tool development.

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    The terms "paradigm" and "paradigm shift" originated in "The Structure of Scientific Revolutions" by Thomas Kuhn. A paradigm can be defined as the generally accepted concepts and practices of a field, and a paradigm shift its replacement in a scientific revolution. A paradigm shift results from a crisis caused by anomalies in a paradigm that reduce its usefulness to a field. Claims of paradigm shifts and revolutions are made frequently in the neurosciences. In this article I will consider neuroscience paradigms, and the claim that new tools and techniques rather than crises have driven paradigm shifts. I will argue that tool development has played a minor role in neuroscience revolutions.The work received no fundin

    Temperature affects the host hematological and cytokine response following experimental ranavirus infection in red-eared sliders (Trachemys scripta elegans).

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    Pathogen-host interactions are important components of epidemiological research, but are scarcely investigated in chelonians. Red-eared sliders (Trachemys scripta elegans), are recognized as a model for frog virus-3 infection (FV3), a ranavirus in the family Iridoviridae that infects multiple classes of ectothermic vertebrates. Previous challenge studies observed differences in disease outcome based on environmental temperature in this species, but the host response was minimally evaluated. We challenged red-eared sliders with an FV3-like ranavirus at both 28°C and 22°C. We monitored several host response variables for 30 days, including: survival (binary outcome and duration), clinical signs, total and differential leukocytes, and select cytokine transcription in the buffy coat (IL-1β, TNFα, IFYg, IL-10). After 30 days, 17% of challenged turtles survived at 28°C (Median survival time [MST]: 15 days, range: 10-30 days) and 50% survived (MST: 28.5 days, range: 23-30 days) at 22°C (range 23-30 days). The most common clinical signs were injection site swelling, palpebral swelling, and lethargy. The heterophil/lymphocyte ratio at 22°C and interleukin-1 beta (IL1β) transcription at both 22°C and 28°C were significantly greater on days 9, 16, and 23 in FV3 challenged groups. Tumor necrosis factor alpha and interleukin-10 were transcribed at detectable levels, but did not display significant differences in mean relative transcription quantity over time. Overall, evidence indicates an over-robust immune response leading to death in the challenged turtles. FV3 remains a risk for captive and free-ranging chelonian populations, and insight to host/pathogen interaction through this model helps to elucidate the timing and intensity of the host response that contribute to mortality
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