1,709 research outputs found

    Novel graphene-based electrodes for energy storage devices

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    Graphene sheets have exceptional electrical, mechanical and optical properties. Graphene-based nanocomposites can be utilized as an electrode for the fabrication of energy storage devices for practical applications. Graphene nanosheets were produced by an enhanced technique including graphite oxidation, ultrasonic treatment, expansion, and chemical reduction

    Artistic Labour: Seeking a Utopian Dimension

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    This is the author accepted manuscript. The final version is available from OpenEdition via http://dx.doi.org/10.4000/cadernosaa.1053This article investigates the notion of artistic labour by elucidating how artists can create ethical social relations to perform “a new, possible world” by reinserting labour and advocacy into their practice. An examination of contemporary works by Ahmet Öğüt and Cevdet Erek who attempt to create micro-utopias by situating artistic labour at their core or by emphasising the power of networks and the “commons” to foster social integration are juxtaposed with the discussion of a possible genealogy of such utopian artistic attempts from the late 1960s and 1970s. The historical trajectory delineates the common denominators of artistic practices that proceed from utopian ideals such as anti-isolation, anti social division, anti self-reflexivity, process instead of object-based work, and investment in human value rather than materialistic value

    Preliminary Evidence of Increased Hippocampal Myelin Content in Veterans with Posttraumatic Stress Disorder.

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    Recent findings suggest the formation of myelin in the central nervous system by oligodendrocytes is a continuous process that can be modified with experience. For example, a recent study showed that immobilization stress increased oligodendrogensis in the dentate gyrus of adult rat hippocampus. Because changes in myelination represents an adaptive form of brain plasticity that has a greater reach in the adult brain than other forms of plasticity (e.g., neurogenesis), the objective of this "proof of concept" study was to examine whether there are differences in myelination in the hippocampi of humans with and without post-traumatic stress disorder (PTSD). We used the ratio of T1-weighted/T2-weighted magnetic resonance image (MRI) intensity to estimate the degree of hippocampal myelination in 19 male veterans with PTSD and 19 matched trauma-exposed male veterans without PTSD (mean age: 43 ± 12 years). We found that veterans with PTSD had significantly more hippocampal myelin than trauma-exposed controls. There was also found a positive correlation between estimates of hippocampal myelination and PTSD and depressive symptom severity. To our knowledge, this is the first study to examine hippocampal myelination in humans with PTSD. These results provide preliminary evidence for stress-induced hippocampal myelin formation as a potential mechanism underlying the brain abnormalities associated with vulnerability to stress

    The hypocretin/orexin antagonist almorexant promotes sleep without impairment of performance in rats.

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    The hypocretin receptor (HcrtR) antagonist almorexant (ALM) has potent hypnotic actions but little is known about neurocognitive performance in the presence of ALM. HcrtR antagonists are hypothesized to induce sleep by disfacilitation of wake-promoting systems whereas GABAA receptor modulators such as zolpidem (ZOL) induce sleep through general inhibition of neural activity. To test the hypothesis that less functional impairment results from HcrtR antagonist-induced sleep, we evaluated the performance of rats in the Morris Water Maze in the presence of ALM vs. ZOL. Performance in spatial reference memory (SRM) and spatial working memory (SWM) tasks were assessed during the dark period after equipotent sleep-promoting doses (100 mg/kg, po) following undisturbed and sleep deprivation (SD) conditions. ALM-treated rats were indistinguishable from vehicle (VEH)-treated rats for all SRM performance measures (distance traveled, latency to enter, time within, and number of entries into, the target quadrant) after both the undisturbed and 6 h SD conditions. In contrast, rats administered ZOL showed impairments in all parameters measured compared to VEH or ALM in the undisturbed conditions. Following SD, ZOL-treated rats also showed impairments in all measures. ALM-treated rats were similar to VEH-treated rats for all SWM measures (velocity, time to locate the platform and success rate at finding the platform within 60 s) after both the undisturbed and SD conditions. In contrast, ZOL-treated rats showed impairments in velocity and in the time to locate the platform. Importantly, ZOL rats only completed the task 23-50% of the time while ALM and VEH rats completed the task 79-100% of the time. Thus, following equipotent sleep-promoting doses, ZOL impaired rats in both memory tasks while ALM rats performed at levels comparable to VEH rats. These results are consistent with the hypothesis that less impairment results from HcrtR antagonism than from GABAA-induced inhibition

    Association between Sleep Duration and 24-Hour Urine Free Cortisol in the MrOS Sleep Study

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    Context Short sleep duration is associated with adverse health outcomes, but the mechanisms involved are unknown. It has been postulated that short sleep duration may elevate cortisol levels, but studies have had conflicting results. It is unclear whether these differing findings may be due to methodological issues, such as assessment of sleep duration. Specifically, objective versus subjective methods of measuring habitual sleep duration may account for the conflicting results found in epidemiological studies. Objective: Our goal was to determine whether habitual sleep duration, measured objectively (by actigraphy) and subjectively (by self-report), was associated with 24-hour urine free cortisol (UFC), a measure of integrated cortisol secretion. Our secondary goal was to determine whether slow wave sleep (SWS, determined by polysomnography) was associated with 24-hour UFC. Design/Setting Cross sectional study of community dwelling older men. Patients/Participants 325 men (mean age = 76.6 years, SD = 5.5) from the Portland site of the MrOS Sleep Study, who underwent 24-hour urine collection, polysomnography, actigraphy and sleep questionnaire. Primary Outcome 24-hour UFC. Results: In this study of community dwelling older men, self-reported sleep duration was inversely related to 24-hour UFC levels. Participants reporting 5 to 8 hours of habitual sleep. However, sleep duration determined by actigraphy was not associated with 24-hour UFC in either univariable or multivariable regression models. SWS was not associated with 24-hour UFC. Conclusion: Objectively measured (i.e., actigraphic) sleep duration is not associated with 24-hour UFC in these community dwelling older men. This finding, together with prior studies, suggests that elevated levels of integrated cortisol secretion is not the mechanisms by which short sleep duration leads to adverse health outcomes

    The Impact of Online Disinformation on Democracy in Taiwan

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    Is online disinformation impacting how voters view political parties? Although many scholars claim that online disinformation (or fake news) is having negative effects on democracy, there are few studies that examine the impact of online disinformation at the individual level. In this study I conducted a randomized survey of 400 Taiwanese respondents in order to assess the impact of online disinformation on their political behavior. The respondents completed one of three surveys and were exposed to either a control article or a social media post containing disinformation. Controlled exposure was found to have a significant impact on the party identification of those exposed to the post for the first time compared to those who had previously been exposed to the post. The results of this study show that disinformation can have an effect on party identification, however further studies are necessary to determine the size and direction of this effect

    Quantifying Social Entities: An Historical-Sociological Critique

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    In formulating social policy the administrative arm of government relies heavily on number-based significations of knowledge, such as needs indicators and performance measures. Relying on numbers increases administrators\u27 confidence in their decisions and shifts responsibility for error away from the decision-maker and towards the numbers. A close examination of the technology of social quantification reveals instability in many of the definitions and codes that needs analysts and program evaluators adopt when numerically inscribing social entities. To deal with these risks, bureaucracies must establish ways of explicitly assessing the uncertainty, imprecision and social construction that often lies behind the evidence presented as numbers, evidence that can easily be accepted on face value and be turned uncritically into decision-making rationales
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