529 research outputs found

    Titan Flagship Mission 3-Degree-of-Freedom Simulation Analysis

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    A NASA flagship mission to Titan, the largest moon of Saturn and the only moon in the solar system with a significant atmosphere, has been designed that uses three separate spacecraft, each requiring significant interaction with the atmosphere. The first vehicle is a Titan lander for lower-atmosphere and surface science. The second is an aerial vehicle for aerial science at approximately 10 km altitude with an expected lifetime of one year. This spacecraft will use the natural winds of Titan to cover a large area over its lifetime. The third vehicle is a Titan orbiter that will interact with the atmosphere in two respects. The first atmospheric interaction is the orbital insertion maneuver that will be accomplished using aerocapture, during which time the hyperbolic approach of 6.5 km/s will be reduced to 1.6 km/s over 41 minutes with an exit periapsis altitude of 130 km. The second atmospheric interaction occurs after a propulsive maneuver has raised the periapsis after aerocapture to 1170 km, where the atmosphere will be sampled over several months. This is the first phase of aerosampling that covers southern latitudes. After a 3.3-year circular science phase at an altitude of 1700 km, a second phase of additional aerosampling is performed sampling northern latitudes. The atmospheric trajectory analysis for these three spacecraft will be discussed throughout this paper

    Methodology for Analysis of Diet Grit Size on Molar Attrition for Fourche Maline and Caddo People

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    Using the Murphy (1959) system for scoring the degree of dentin exposure, Fourche Maline (Woodland) molars show a greater attrition rate than Caddo (Mississippian) molars. Archeological evidence suggests that this differential in attrition rates is caused by the use of stone grinders for food preparation in the Fourche Maline culture and their absence among the Caddo. Analysis of scratches on the occlusal surface of molars from these samples confirms this hypothesis. Several techniques for observing these scratches and reconstructing the grit sizes and grit particle frequencies responsible for this differential abrasion are evaluated

    Marine area governance and management in the Gulf of Maine : a case study

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    This case study provides a description and evaluation of marine area governance and management in the Gulf of Maine. On the advice of the Oversight Committee, we began the study at a broad level by identifying marine resources, uses of the resources, existing management regimes, and conflicts among users of the resources. The results of these initial reviews are collected in the tables in Appendix A. The Oversight Committee also suggested that we develop a chronology of important events relating to marine area governance and management in the Gulf of Maine, which is included as Appendix B. As is clear from even a quick scan of the material in Appendix A, almost every conceivable use of the marine environment occurs in the Gulf of Maine at some scale. However, some of these uses are more problematic than others in terms of the governance and management problems they engender. Rather than take a broadbrush approach that might not have done justice to any of the region's many ocean resources and uses, we decided to focus the case study on one or more of its most difficult and consequential governance and management issues. The initial survey enabled us to focus in on a subset of resources, use conflicts, and governance issues, namely those associated mainly with marine fisheries governance and management. Several considerations support the argument for a focus on fisheries governance and management. The marine fisheries are a regional-scale resource and industry, due to the mobility of the fish stocks, the geographic distribution of the users of the resource, and the fact that governance institutions have been designed to have regionwide authority. Thus fisheries mismanagement has the potential to inflict widespread social detriment and significant economic losses. Indeed, the net cost of depleted groundfish stocks under the current management structure, relative to the condition of stocks in an optimally managed fishery, has been estimated at about $139 million annually, or just under one-fifth the landed value of the entire Gulf of Maine commercial catch. Other ocean resources with potentially regional impacts, such as offshore energy, are not being pursued in the Gulf of Maine region at levels that pose significant concerns. Consequently, non-fishery resource management problems in the Gulf of Maine are, for the most part, local in scale, of comparatively minor economic significance, and not unique to the region. There is no evidence, for example, of "system-wide degradation of marine environmental quality in the Gulf of Maine. . . . The Gulf as a whole remains relatively clean, although the deep central basins appear to be accumulating several pollutants, including PAHs and PCBs" (GOMCME 1994; see also Dow and Braasch 1996 and Gould, Clark, and Thurberg 1994). Given that most pollutants of concern are concentrated in inshore waters near urban areas and in the mouths of industrialized rivers, it is not at all clear that they could be dealt with more effectively or efficiently at the regional level. In sum, our focus on fisheries reflects our judgment that the greatest net benefits might be obtained from improvements in the governance and management of these marine resources within the Gulf of Maine region.This case study was produced for the purposes of the Committee on Marine Area Governance and Management of the National Research Council (NRC), Agreement No. DOT -3830-96-002

    Navigating distance learning technologies using team teaching

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    In 2004, the American Association of Colleges of Nursing (AACN) adopted the position to move the current level of preparation necessary for advanced practice nurse (APN) roles from the master\u27s degree to the doctoral level. AACN also called for educating APNs and other nurses seeking top leadership and clinical roles in Doctor of Nursing Practice (DNP) Programs. In September 2007, the Jefferson School of Nursing welcomed its first cohort of 18 DNP students. Students represented a wide variety of practice specialties including acute care, primary care, healthcare administration, population health, education and industry. Twenty students comprise the second cohort entering in September 2008. Nationwide, Jefferson is one of 79 schools of nursing offering a DNP degree

    Development and initial validation of the Seated Posture Scale

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    —Literature shows that some health outcomes (e.g., eating, breathing, and speaking) are directly related to posture. Evidence of outcomes mediated by wheelchair seated posture is limited to interface pressure, physical function, and wheelchair skills and safety. This study’s purpose was to develop and validate a rapid, low-burden, paper-pencil assessment of wheelchair seated posture for research use and to test feasibility of its use with a sample of older adults. We used a prospective design and a convenience sample of older adults who were receiving rehabilitation services in a community living center. Forty-nine older wheelchair users participated. Main measures were the Seated Posture Scale (SPS), Modified Ashworth Scale, Barthel Index, Visual Descriptor Scale, scale-content validity index (S-CVI), Cronbach alpha, and test-retest reliability. Rating by six experts yielded the overall content validity score (S-CVI) of 0.744. Total SPS score correlated positively with physical function (Barthel Index, r = 0.46, p \u3c 0.001) and negatively with muscle tone (Modified Ashworth Scale, r = –0.44, p = 0.001), supporting SPS construct validity. Internal consistency was 0.66 (Cronbach alpha). Test-retest reliability yielded Pearson product-moment correlations of 0.89 to 0.99. We conclude that the SPS has sufficient preliminary validity and reliability to support its use as an evaluation of wheelchair seated posture in outcomes research

    Vibrio vulnificus MO6-24/O Lipopolysaccharide Stimulates Superoxide Anion, Thromboxane B\u3csub\u3e2\u3c/sub\u3e, Matrix Metalloproteinase-9, Cytokine and Chemokine Release by Rat Brain Microglia in Vitro

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    Although human exposure to Gram-negative Vibrio vulnificus (V. vulnificus) lipopolysaccharide (LPS) has been reported to result in septic shock, its impact on the central nervous system’s innate immunity remains undetermined. The purpose of this study was to determine whether V. vulnificus MO6-24/O LPS might activate rat microglia in vitro and stimulate the release of superoxide anion (O2−), a reactive oxygen species known to cause oxidative stress and neuronal injury in vivo. Brain microglia were isolated from neonatal rats, and then treated with either V. vulnificus MO6-24/O LPS or Escherichia coli O26:B6 LPS for 17 hours in vitro. O2− was determined by cytochrome C reduction, and matrix metalloproteinase-2 (MMP-2) and MMP-9 by gelatinase zymography. Generation of cytokines tumor necrosis factor alpha (TNF-α), interleukin-1 alpha (IL-1α), IL-6, and transforming growth factor-beta 1 (TGF-β1), chemokines macrophage inflammatory protein (MIP-1α)/chemokine (C-C motif) ligand 3 (CCL3), MIP-2/chemokine (C-X-C motif) ligand 2 (CXCL2), monocyte chemotactic protein-1 (MCP-1)/CCL2, and cytokine-induced neutrophil chemoattractant-2alpha/beta (CINC-2α/β)/CXCL3, and brain-derived neurotrophic factor (BDNF), were determined by specific immunoassays. Priming of rat microglia by V. vulnificus MO6-24/O LPS in vitro yielded a bell-shaped dose-response curve for PMA (phorbol 12-myristate 13-acetate)-stimulated O2− generation: (1) 0.1–1 ng/mL V. vulnificus LPS enhanced O2− generation significantly but with limited inflammatory mediator generation; (2) 10–100 ng/mL V. vulnificus LPS maximized O2− generation with concomitant release of thromboxane B2 (TXB2), matrix metalloproteinase-9 (MMP-9), and several cytokines and chemokines; (3) 1000–100,000 ng/mL V. vulnificus LPS, with the exception of TXB2, yielded both attenuated O2− production, and a progressive decrease in MMP-9, cytokines and chemokines investigated. Thus concentration-dependent treatment of neonatal brain microglia with V. vulnificus MO6-24/O LPS resulted in a significant rise in O2− production, followed by a progressive decrease in O2− release, with concomitant release of lactic dehydrogenase (LDH), and generation of TXB2, MMP-9, cytokines and chemokines. We hypothesize that the inflammatory mediators investigated may be cytotoxic to microglia in vitro, by an as yet undetermined autocrine mechanism. Although V. vulnificus LPS was less potent than E. coli LPS in vitro, inflammatory mediator release by the former was clearly more efficacious. Finally, we hypothesize that should V. vulnificus LPS gain entry into the CNS, it would be possible that microglia might become activated, resulting in high levels of O2− as well as neuroinflammatory TXB2, MMP-9, cytokines and chemokines

    Conceptualisations of children’s wellbeing at school: the contribution of recognition theory

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    A large study in Australian schools aimed to elucidate understandings of ‘wellbeing’ and of factors in school life that contribute to it. Students and teachers understood wellbeing primarily, and holistically, in terms of interpersonal relationships, in contrast to policy documents which mainly focused on ‘problem areas’ such as mental health. The study also drew on recognition theory as developed by the social philosopher Axel Honneth. Results indicate that recognition theory may be useful in understanding wellbeing in schools, and that empirical research in schools may give rise to further questions regarding theory

    (3R,5S,7as)-(3,5-bis(4-Fluorophenyl)tetrahydro-1H-oxazolo[3,4-c]oxazol-7a-yl)methanol: A Novel Neuroprotective Agent

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    Compounds that interact with microtubules, such as paclitaxel, have been shown to possess protective properties against β-amyloid (Aβ)-induced neurodegeneration associated with Alzheimer's disease. In this work, the novel agent (3R,5S,7as)-(3,5-bis(4-fluorophenyl)tetrahydro-1H-oxazolo[3,4-c]oxazol-7a-yl)methanol was investigated for effectiveness in protecting neurons against several toxic stimuli and its interaction with the microtubule network. Exposure of neuronal cultures to Aβ peptide in the presence of 5 nM (3R,5S,7as)-(3,5-bis(4-fluorophenyl)tetrahydro-1H-oxazolo[3,4-c]oxazol-7a-yl)methanol resulted in a 50% increase in survival. Neuronal cultures treated with other toxic stimuli such as staurosporine, thapsigargin, paraquat and H2O2 showed significantly enhanced survival in the presence of (3R,5S,7as)-(3,5-bis(4-fluorophenyl)tetrahydro-1H-oxazolo[3,4-c]oxazol-7a-yl)methanol. Microtubule binding and tubulin assembly studies revealed differences compared to paclitaxel, but confirmed the interaction of (3R,5S,7as)-(3,5-bis(4-fluorophenyl)tetrahydro-1H-oxazolo[3,4-c]oxazol-7a-yl)methanol with microtubules. Furthermore, in vitro studies using bovine brain microvessel endothelial cells experiments suggest that (3R,5S,7as)-(3,5-bis(4-fluorophenyl)tetrahydro-1H-oxazolo[3,4-c]oxazol-7a-yl)methanol can readily cross the blood-brain barrier in a passive manner

    Breakfast glycaemic index and exercise: combined effects on adolescents' cognition

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    The aim of the present study was to examine the combined effects of breakfast glycaemic index (GI) and a mid-morning bout of exercise on adolescents’ cognitive function. Participants were randomly allocated to a high or low GI breakfast group in a mixed research design, where each participant completed two experimental trials (exercise and resting). Forty-two adolescents (12.4±0.5 years old), undertook a bout of exercise (ten repeats of level one of the multi-stage fitness test; exercise trial) or continued to rest (resting trial) following consumption of either a high or low GI breakfast. A battery of cognitive function tests (visual search test, Stroop test and Sternberg paradigm) was completed 30 min before and 45 min following the exercise. Average heart rate during exercise was 170±15 beats.min-1. On the complex level of the Stroop test, response times improved across the morning following the low GI breakfast on both the exercise and resting trials, though the improvement was greatest on the exercise trial. However, response times only improved on the resting trial following the high GI breakfast (p = 0.012). On the 5 letter level of the Sternberg paradigm, response times improved across the morning following the low GI breakfast (regardless of exercise) and only on the exercise trial following the high GI breakfast (p = 0.019). The findings of the present study suggest that the combined effects of breakfast GI and exercise in adolescents depend upon the component of cognitive function examined. A low GI breakfast and mid-morning bout of exercise were individually beneficial for response times on the Sternberg paradigm, whereas they conferred additional benefits for response times on the Stroop test
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