3,104 research outputs found

    Inclusive Scholarship: Developing Black Studies in the United States

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    Brings together four reports commissioned between 1982 and 2000 that examine the history of African American Studies, its impact, and its institutionalization. Reviews Ford's grantmaking to African American Studies programs from 1982 to 2007

    The John Hope Gateway Biodiversity Centre

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    The John Hope Gateway Biodiversity Centre

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    Nanoparticle Networks Reduce the Flammability of Polymer Nanocomposites

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    Synthetic polymer materials are rapidly replacing more traditional inorganic materials such as metals and natural polymeric materials such as wood. Since these novel materials are flammable, they require modifications to decrease their flammability through the addition of flame-retardant (FR) compounds. Recently, environmental regulation has restricted the use of some halogenated FR additives, initiating a search for alternative FR additives. Nanoparticle fillers are highly attractive for this purpose since they can simultaneously improve both the physical and flammability properties of the polymer nanocomposite. We show that carbon nanotubes can surpass nano-clays as effective FR additives if they form a jammed network structure within the polymer matrix, such that the material as a whole behaves rheologically like a gel. We find this kind of network formation for a variety of highly extended carbon-based nanoparticles: single and multi-walled nanotubes, as well as carbon nanofibers

    Effectiveness of antipsychotics used in first-episode psychosis: a naturalistic cohort study

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    Background: One year of antipsychotic treatment from symptom remission is recommended following a first episode of psychosis (FEP). Aims: To investigate the effectiveness of commonly used antipsychotic medications in FEP. Method: A retrospective cohort study of naturalistic treatment of patients (N=460) accepted by FEP services across seven UK sites. Treatment initiation to all-cause discontinuation determined from case files. Results: Risk of treatment discontinuation is greatest within 3 months of treatment initiation. Risperidone had longest median survival time. No significant differences were observed in time to discontinuation between commonly used antipsychotics on multivariable Cox regression analysis. Poor adherence and efficacy failure were the most common reasons for discontinuation. Conclusions: Effectiveness differences appear not to be a current reason for antipsychotic choice in FEP. Adherence strategies and weighing up likely adverse effects should be the clinical focus

    Method for the Destruction of Endotoxin in Synthetic Spider Silk Proteins

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    Although synthetic spider silk has impressive potential as a biomaterial, endotoxin contamination of the spider silk proteins is a concern, regardless of the production method. The purpose of this research was to establish a standardized method to either remove or destroy the endotoxins present in synthetic spider silk proteins, such that the endotoxin level was consistently equal to or less than 0.25 EU/mL, the FDA limit for similar implant materials. Although dry heat is generally the preferred method for endotoxin destruction, heating the silk proteins to the necessary temperatures led to compromised mechanical properties in the resultant materials. In light of this, other endotoxin destruction methods were investigated, including caustic rinses and autoclaving. It was found that autoclaving synthetic spider silk protein dopes three times in a row consistently decreased the endotoxin level 10–20 fold, achieving levels at or below the desired level of 0.25 EU/mL. Products made from triple autoclaved silk dopes maintained mechanical properties comparable to products from untreated dopes while still maintaining low endotoxin levels. Triple autoclaving is an effective and scalable method for preparing synthetic spider silk proteins with endotoxin levels sufficiently low for use as biomaterials without compromising the mechanical properties of the materials

    M87: A Misaligned BL LAC?

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    The nuclear region of M87 was observed with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST) at 6 epochs, spanning 18 months, after the HST image quality was improved with the deployment of the corrective optics (COSTAR) in December 1993. From the FOS target acquisition data, we have established that the flux from the optical nucleus of M87 varies by a factor ~2 on time scales of ~2.5 months and by as much as 25% over 3 weeks, and remains unchanged (<= 2.5%) on time scales of ~1 day. The changes occur in an unresolved central region <= 5 pc in diameter, with the physical size of the emitting region limited by the observed time scales to a few hundred gravitational radii. The featureless continuum spectrum becomes bluer as it brightens while emission lines remain unchanged. This variability combined with the observations of the continuum spectral shape, strong relativistic boosting and the detection of significant superluminal motions in the jet, strongly suggest that M87 belongs to the class of BL Lac objects but is viewed at an angle too large to reveal the classical BL Lac properties.Comment: 12 pages, 3 Postscript figure
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