1,512 research outputs found

    Air pollution & the brain: Subchronic diesel exhaust exposure causes neuroinflammation and elevates early markers of neurodegenerative disease

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    Background Increasing evidence links diverse forms of air pollution to neuroinflammation and neuropathology in both human and animal models, but the effects of long-term exposures are poorly understood. Objective We explored the central nervous system consequences of subchronic exposure to diesel exhaust (DE) and addressed the minimum levels necessary to elicit neuroinflammation and markers of early neuropathology. Methods Male Fischer 344 rats were exposed to DE (992, 311, 100, 35 and 0 μg PM/m3) by inhalation over 6 months. Results DE exposure resulted in elevated levels of TNFα at high concentrations in all regions tested, with the exception of the cerebellum. The midbrain region was the most sensitive, where exposures as low as 100 μg PM/m3 significantly increased brain TNFα levels. However, this sensitivity to DE was not conferred to all markers of neuroinflammation, as the midbrain showed no increase in IL-6 expression at any concentration tested, an increase in IL-1β at only high concentrations, and a decrease in MIP-1α expression, supporting that compensatory mechanisms may occur with subchronic exposure. Aβ42 levels were the highest in the frontal lobe of mice exposed to 992 μg PM/m3 and tau [pS199] levels were elevated at the higher DE concentrations (992 and 311 μg PM/m3) in both the temporal lobe and frontal lobe, indicating that proteins linked to preclinical Alzheimer\u27s disease were affected. α Synuclein levels were elevated in the midbrain in response to the 992 μg PM/m3 exposure, supporting that air pollution may be associated with early Parkinson\u27s disease-like pathology. Conclusions Together, the data support that the midbrain may be more sensitive to the neuroinflammatory effects of subchronic air pollution exposure. However, the DE-induced elevation of proteins associated with neurodegenerative diseases was limited to only the higher exposures, suggesting that air pollution-induced neuroinflammation may precede preclinical markers of neurodegenerative disease in the midbrain

    Retrieving Multi-Entity Associations: An Evaluation of Combination Modes for Word Embeddings

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    Word embeddings have gained significant attention as learnable representations of semantic relations between words, and have been shown to improve upon the results of traditional word representations. However, little effort has been devoted to using embeddings for the retrieval of entity associations beyond pairwise relations. In this paper, we use popular embedding methods to train vector representations of an entity-annotated news corpus, and evaluate their performance for the task of predicting entity participation in news events versus a traditional word cooccurrence network as a baseline. To support queries for events with multiple participating entities, we test a number of combination modes for the embedding vectors. While we find that even the best combination modes for word embeddings do not quite reach the performance of the full cooccurrence network, especially for rare entities, we observe that different embedding methods model different types of relations, thereby indicating the potential for ensemble methods.Comment: 4 pages; Accepted at SIGIR'1

    Achieving Access to Mental Health Care for School-Aged Children in Rural Communities

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    With creativity and collaboration, children in rural communities who have the same mental health needs as children in urban areas can achieve access to mental health care. This review of the literature explores barriers to mental health services facing school-aged children in rural communities, focusing on how challenges unique to rural communities affect the type of care rural children ultimately receive. This review aligns with the NREA Research Agenda area “access to counseling/mental health services”. The discussion incorporates national trends in the treatment of children with mental health concerns and highlights some surprising facts about the state of mental health care in rural school and examines the following factors: (1) belief, (2) family poverty, (3) school support, (4) community resources, and (5) awareness. The review concludes by outlining opportunities for advocacy and proposed solutions for improving mental health care access for rural children and suggesting directions for future research

    Investigating 3D Printer Residual Data

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    The continued adoption of Additive Manufacturing (AM) technologies is raising concerns in the security, forensics, and intelligence gathering communities. These concerns range from identifying and mitigating compromised devices, to theft of intellectual property, to sabotage, to the production of prohibited objects. Previous research has provided insight into the retrieval of configuration information maintained on the devices, but this work shows that the devices can additionally maintain information about the print process. Comparisons between before and after images taken from an AM device reveal details about the device’s activities, including printed designs, menu interactions, and the print history. Patterns in the storage of that information also may be useful for reducing the amount of data that needs to be examined during an investigation. These results provide a foundation for future investigations regarding the tools and processes suitable for examining these devices

    Analysis, Design, and Operation of a Spherical Inverted-F Antenna

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    This thesis presents the analysis, design, and fabrication of a spherical inverted-F antenna (SIFA). The SIFA consists of a spherically conformal rectangular patch antenna recessed into a quarter section of a metallic sphere. The sphere acts as a ground plane, and a metal strip shorts the patch to the metallic sphere. The SIFA incorporates planar microstrip design into a conformal spherical geometry to better meet the design constraints for integrated wireless sensors. The SIFA extends a well-established technology into a new application space, including microsatellites, mobile sensor networks, and wireless biomedical implants. The complete SIFA design depends on several parameters, several of which parallel planar design variables. A modified transmission line model determines the antenna input impedance based on the sphere's inner and outer radii, the patch length and width, short length and width, and feed position. The SIFA can be tuned to the desired frequency band by choosing the proper outer radius, after which the antenna can be matched by tuning the short characteristics, patch dimensions, and feed position. The fabricated design was chosen to operate at the MICS band (402-405 MHz), a popular band for biomedically implanted devices. An initial design was constructed with Styrofoam (epsilon r approximately equal to 1) and copper tape. Simulation in HFSS corroborates that SIFA operation incorporates the MICS band, with resonant frequency of 404 MHz and 32 MHz (7.9%) bandwidth. The fabricated prototype performs similarly, with a resonant frequency of 407 MHz and 19 (4.7%) MHz bandwidth. Following fabrication, several modifications were implemented to miniaturize the SIFA and introduce additional functionality. Slot loading and dielectric coating were implemented to achieve SIFA miniaturization. Multiple elements were also introduced to achieve dual band operation and beam steering. A miniaturized SIFA was investigated in several biological media, and a lossy coating implemented to maintain impedance match in several different media, with the goal of retaining a matched impedance bandwidth in the MICS band

    Understanding Skill in EVA Mass Handling

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    In this report we describe the details of our empirical protocol effort investigating skill in extravehicular mass handling using NASA's principal mass handling simulator, the precision air bearing floor. Contents of this report include a description of the necessary modifications to the mass handling simulator; choice of task, and the description of an operationally relevant protocol. Our independent variables are presented in the context of the specific operational issues they were designed to simulate. The explanation of our dependent variables focuses on the specific data processing procedures used to transform data from common laboratory instruments into measures that are relevant to a special class of nested control systems (discussed in Volume 1): manual interactions between an individual and the substantial environment. The data reduction is explained in the context of the theoretical foundation described in Volume 1. Finally as a preface to the presentation of the empirical data in Volume 3 of this report series, a set of detailed hypotheses is presented

    Understanding Skill in EVA Mass Handling

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    This report describes the theoretical and operational foundations for our analysis of skill in extravehicular mass handling. A review of our research on postural control, human-environment interactions, and exploratory behavior in skill acquisition is used to motivate our analysis. This scientific material is presented within the context of operationally valid issues concerning extravehicular mass handling. We describe the development of meaningful empirical measures that are relevant to a special class of nested control systems: manual interactions between an individual and the substantial environment. These measures are incorporated into a unique empirical protocol implemented on NASA's principal mass handling simulator, the precision air-bearing floor, in order to evaluate skill in extravehicular mass handling. We discuss the components of such skill with reference to the relationship between postural configuration and controllability of an orbital replacement unit, the relationship between orbital replacement unit control and postural stability, the relationship between antecedent and consequent movements of an orbital replacement unit, and the relationship between antecedent and consequent postural movements. Finally, we describe our expectations regarding the operational relevance of the empirical results as it pertains to extravehicular activity tools, training, monitoring, and planning

    Effects of Spaceflight on the Modulation of Shock Wave Transmission to the Head During Locomotion

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    The ability to maintain gaze stability during locomotion requires the normal function and integration of the vestibulo-ocular reflex, vestibulo and cervico-colic reflexes with effective coordination between the trunk and lower limb segments. One hypothesized constraint on the coordination between segments during locomotion is the regulation of energy flow or shock wave transmissions through the body at high impact phases with the support surface. Allowing these excessive transmissions of energy to the head may result in compromised gaze stability during locomotion. The aim of this study was to determine the effects of microgravity adaptation on the transmissibility of shock wave to the head during locomotion. Before and after spaceflight (3-6 months) six subjects walked (6.4 km/h) on a motorized treadmill while fixating their gaze on a centrally located earth-fixed target. Triaxial accelerometers mounted on the shank and the head measured the shock wave transmission through the body during locomotion. During postflight locomotion the peak shock at the shank and the head were significantly reduced, however, the ratio of peak head to shank shock was significantly increased. These results indicate that exposure to spaceflight causes adaptive modifications in the short-latency vestibulospinal head stabilization responses required to compensate for the rapid shocks transmitted to the head during locomotion. This study was supported by NASA

    Terminal Pleistocene through Holocene Evolution of Whiteoak Bottoms, a Southern Blue Ridge Mountains Peatland

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    Abstract Our primary objective was to develop an understanding of the geomorphic evolution of Whiteoak Bottoms (WOB), a peatland along the Nantahala River in the Southern Blue Ridge Mountains (SBRM) of western North Carolina. Radiocarbon dates directly above basal fluvial sediments returned ages of 14,000 to 15,000 cal yr BP. These ages indicate WOB is the oldest dated peatland in the SBRM and that such wetlands have persisted throughout the Holocene. Below the relatively flat surface of the wetland, paleochannels, similar to those of the modern channel, were found; suggesting a persistence of similar channel morphology since the terminal Pleistocene. The wetland's stratigraphy reveals a consistent pattern with basal fluvial cobbles being overlain by sandy channel-fill grading up into peat. Two different distinct inorganic deposits separate the lower organic deposits from the sapric peat deposits at the surface. Interestingly, we estimate more than 56% of the organic matter preserved by the wetland accumulated during the first 6,000 years of development. Overall, WOB has accumulated approximately 424 Mg/ha of carbon during the past 15,000 years. Maintenance of this wetland initially depended on the Nantahala River; however, today it is ground water and beavers that allows for the persistence of this rare landscape
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