3,360 research outputs found

    Optimization of design parameters for spacecraft nickel-cadmium cells containing recombination and control electrodes Quarterly report

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    Cycle capability of electrochemical cells built with oxygen recombination and oxygen sensing control electrode

    Is There Extra Cost of Institutional Care for MS Patients?

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    Throughout life, patients with multiple sclerosis (MS) require increasing levels of support, rehabilitative services, and eventual skilled nursing facility (SNF) care. There are concerns that access to SNF care for MS patients is limited because of perceived higher costs of their care. This study compares costs of caring for an MS patient versus those of a typical SNF patient. We merged SNF cost report data with the 2001-2006 Nursing Home Minimum Data Set (MDS) to calculate percentage of MS residents-days and facility case-mix indices (CMIs). We estimated the average facility daily cost using hybrid cost functions, adjusted for facility ownership, average facility wages, CMI-adjusted number of SNF days, and percentage of MS residents-days. We describe specific characteristics of SNF with high and low MS volumes and examine any sources of variation in cost. MS patients were no longer more costly than typical SNF patients. A greater proportion of MS patients had no significant effect on facility daily costs (P = 0.26). MS patients were more likely to receive care in government-owned facilities (OR = 1.904) located in the Western (OR = 2.133) and Midwestern (OR = 1.3) parts of the USA (P < 0.05). Cost of SNF care is not a likely explanation for the perceived access barriers that MS patients face

    Characterization of recombination and control electrodes for spacecraft nickel- cadmium cells

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    Characterization of recombination and control electrodes for spacecraft nickel cadmium cell

    Using institutions to moderate separatist tendencies : a focus on Iraqi Kurdistan

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Political Science, 2005."February 2005."Includes bibliographical references.This thesis offers an alternate theory to the problem of secessionism by integrating two separate fields of research: nationalism and constitutional engineering. In particular, I apply two prominent theories of nationalism, those of Ernest Gellner and Benedict Anderson, to the problem of constitutional engineering. The theories developed by Gellner and Anderson have furthered our understanding of the historical and evolutionary processes of nationhood and nationalism. I argue that the insight offered by these theories can therefore better guide policy makers, scholars, and constitutional engineers in the design of political institutions for deeply-divided societies. The engineering of institutions has the capacity to contain separatist conflict by striking at what I argue are the two necessary cause of secessionism - desire and ability. In my thesis I focus on one case study in particular, that of Iraqi Kurdistan. I argue that a secessionist movement by Iraqi Kurds can best be thwarted by applying a two-pronged strategy: First, devolve enough power to the Kurds so that their rights as a minority group are protected and their desire for self-rule is fulfilled. Likewise, ensure the representation of Kurds in all levels of government. Second, encourage diversity within the Kurdish political arena. Both components of this strategy can be achieved by adopting a proportional representation electoral formula, selecting a territorially-based federalism, and choosing a parliamentary system.by Adele B. Weinstock.S.M

    On Open and Collaborative Software Development in the DoD

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    Proceedings Paper (for Acquisition Research Program)The US Department of Defense (specifically, but not limited to, the DoD CIO Clarifying Guidance Regarding Open Source Software, DISA launch of Forge.mil and OSD Open Technology Development Roadmap Plan) has called for increased use of open source software and the adoption of best practices from the free/open source software (F/OSS) community to foster greater reuse and innovation between programs in the DoD. In our paper, we examine some key aspects of open and collaborative software development inspired by the success of the F/OSS movement as it might manifest itself within the US DoD. This examination is made from two perspectives: the reuse potential among DoD programs sharing software and the incentives, strategies and policies that will be required to foster a culture of collaboration needed to achieve the benefits indicative of F/OSS. Our conclusion is that to achieve predictable and expected reuse, not only are technical infrastructures needed, but also a shift to the business practices in the software development and delivery pattern seen in the traditional acquisition lifecycle is needed. Thus, there is potential to overcome the challenges discussed within this paper to engender a culture of openness and community collaboration to support the DoD mission.Naval Postgraduate School Acquisition Research ProgramApproved for public release; distribution is unlimited

    Amyloid beta and diabetic pathology cooperatively stimulate cytokine expression in an Alzheimer's mouse model

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    Background Diabetes is a risk factor for developing Alzheimer's disease (AD); however, the mechanism by which diabetes can promote AD pathology remains unknown. Diabetes results in diverse molecular changes in the brain, including dysregulation of glucose metabolism and loss of cerebrovascular homeostasis. Although these changes have been associated with increased A beta pathology and increased expression of glial activation markers in APPswe/PS1dE9 (APP/PS1) mice, there has been limited characterization, to date, of the neuroinflammatory changes associated with diabetic conditions. Methods To more fully elucidate neuroinflammatory changes associated with diabetes that may drive AD pathology, we combined the APP/PS1 mouse model with either high-fat diet (HFD, a model of pre-diabetes), the genetic db/db model of type 2 diabetes, or the streptozotocin (STZ) model of type 1 diabetes. We then used a multiplexed immunoassay to quantify cortical changes in cytokine proteins. Results Our analysis revealed that pathology associated with either db/db, HFD, or STZ models yielded upregulation of a broad profile of cytokines, including chemokines (e.g., MIP-1 alpha, MIP-1 beta, and MCP-1) and pro-inflammatory cytokines, including IL-1 alpha, IFN-gamma, and IL-3. Moreover, multivariate partial least squares regression analysis showed that combined diabetic-APP/PS1 models yielded cooperatively enhanced expression of the cytokine profile associated with each diabetic model alone. Finally, in APP/PS1xdb/db mice, we found that circulating levels of A beta 1-40, A beta 1-42, glucose, and insulin all correlated with cytokine expression in the brain, suggesting a strong relationship between peripheral changes and brain pathology. Conclusions Altogether, our multiplexed analysis of cytokines shows that Alzheimer's and diabetic pathologies cooperate to enhance profiles of cytokines reported to be involved in both diseases. Moreover, since many of the identified cytokines promote neuronal injury, A beta and tau pathology, and breakdown of the blood-brain barrier, our data suggest that neuroinflammation may mediate the effects of diabetes on AD pathogenesis. Therefore, strategies targeting neuroinflammatory signaling, as well as metabolic control, may provide a promising strategy for intervening in the development of diabetes-associated AD

    Validation of the Harvard Lyman-α in situ water vapor instrument: Implications for the mechanisms that control stratospheric water vapor

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    Building on previously published details of the laboratory calibrations of the Harvard Lyman-α photofragment fluorescence hygrometer (HWV) on the NASA ER-2 and WB-57 aircraft, we describe here the validation process for HWV, which includes laboratory calibrations and intercomparisons with other Harvard water vapor instruments at water vapor mixing ratios from 0 to 10 ppmv, followed by in-flight intercomparisons with the same Harvard hygrometers. The observed agreement exhibited in the laboratory and during intercomparisons helps corroborate the accuracy of HWV. In light of the validated accuracy of HWV, we present and evaluate a series of intercomparisons with satellite and balloon borne water vapor instruments made from the upper troposphere to the lower stratosphere in the tropics and midlatitudes. Whether on the NASA ER-2 or WB-57 aircraft, HWV has consistently measured about 1–1.5 ppmv higher than the balloon-borne NOAA/ESRL/GMD frost point hygrometer (CMDL), the NOAA Cryogenic Frost point Hygrometer (CFH), and the Microwave Limb Sounder (MLS) on the Aura satellite in regions of the atmosphere where water vapor is <10 ppmv. Comparisons in the tropics with the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite show large variable differences near the tropopause that converge to ~10% above 460 K, with HWV higher. Results we show from the Aqua Validation and Intercomparison Experiment (AquaVIT) at the AIDA chamber in Karlsruhe do not reflect the observed in-flight differences. We illustrate that the interpretation of the results of comparisons between modeled and measured representations of the seasonal cycle of water entering the lower tropical stratosphere is dictated by which data set is used

    Mode-coupling and nonlinear Landau damping effects in auroral Farley-Buneman turbulence

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    The fundamental problem of Farley-Buneman turbulence in the auroral EE-region has been discussed and debated extensively in the past two decades. In the present paper we intend to clarify the different steps that the auroral EE-region plasma has to undergo before reaching a steady state. The mode-coupling calculation, for Farley-Buneman turbulence, is developed in order to place it in perspective and to estimate its magnitude relative to the anomalous effects which arise through the nonlinear wave-particle interaction. This nonlinear effect, known as nonlinear ``Landau damping'' is due to the coupling of waves which produces other waves which in turn lose energy to the bulk of the particles by Landau damping. This leads to a decay of the wave energy and consequently a heating of the plasma. An equation governing the evolution of the field spectrum is derived and a physical interpration for each of its terms is provided

    Development and analysis of the Software Implemented Fault-Tolerance (SIFT) computer

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    SIFT (Software Implemented Fault Tolerance) is an experimental, fault-tolerant computer system designed to meet the extreme reliability requirements for safety-critical functions in advanced aircraft. Errors are masked by performing a majority voting operation over the results of identical computations, and faulty processors are removed from service by reassigning computations to the nonfaulty processors. This scheme has been implemented in a special architecture using a set of standard Bendix BDX930 processors, augmented by a special asynchronous-broadcast communication interface that provides direct, processor to processor communication among all processors. Fault isolation is accomplished in hardware; all other fault-tolerance functions, together with scheduling and synchronization are implemented exclusively by executive system software. The system reliability is predicted by a Markov model. Mathematical consistency of the system software with respect to the reliability model has been partially verified, using recently developed tools for machine-aided proof of program correctness

    Relativity principles in 1+1 dimensions and differential aging reversal

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    We study the behavior of clocks in 1+1 spacetime assuming the relativity principle, the principle of constancy of the speed of light and the clock hypothesis. These requirements are satisfied by a class of Finslerian theories parametrized by a real coefficient β\beta, special relativity being recovered for β=0\beta=0. The effect of differential aging is studied for the different values of β\beta. Below the critical values β=1/c|\beta| =1/c the differential aging has the usual direction - after a round trip the accelerated observer returns younger than the twin at rest in the inertial frame - while above the critical values the differential aging changes sign. The non-relativistic case is treated by introducing a formal analogy with thermodynamics.Comment: 12 pages, no figures. Previous title "Parity violating terms in clocks' behavior and differential aging reversal". v2: shortened introduction, some sections removed, pointed out the relation with Finsler metrics. Submitted to Found. Phys. Let
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