3,476 research outputs found

    Towards a novel optical trace oxygen sensor for commercial use

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    Petrogenesis of Mid-Proterozoic Granitic Magmas: Examples from Central and West Texas

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    Circa 1.1 Ga granitic magmatism in Texas was manifested as two compositional groups: (1) the 1.12 Ga Red Bluff granitic suite in west Texas; and (2) 1.12-1.07 Ga granites of the Llano uplift of central Texas. Both suites share some characteristics typical of \u27anorogenic\u27 granites (e.g. potassium- and iron-rich bulk compositions, Fe-rich hydrous silicates, emplacement conditions involving low oxygen fugacities and water contents) and exhibit similar isotopic characteristics. However, rock associations, mineral chemistries, and trace element compositions of the two suites are distinct and no single petrogenetic model for the two suites is possible. The Red Bluff granitic suite includes cogenetic syenites, quartz syenites and granites; transitional ferrobasaltic dikes are also present. In contrast, syenitic and mafic rocks are not associated with the Llano granites. The Llano granites contain biotite and calcic amphibole with lower Fe/(Fe+Mg) ratios compared to those occurring in the Red Bluff rocks. Alkali amphiboles (e.g. arfvedsonite) occur in the Red Bluff granites but not in the Llano granites. The Red Bluff granitoids are characterized by high FeOT/MgO ratios, high (Na2O+K2O), high concentrations of HFSE and rare earth elements (REE), and other features typical of A-type, \u27within-plate\u27 granites [e.g. the Pikes Peak batholith (PPB)]. The Llano granites are geochemically distinct with generally higher P2O5 and Sr, lower Na2O, FeOT/MgO, Zr, Y and REE, and much lower Ta and Nb. Nd isotopic data overlap between the two granite suites and have \u27juvenile\u27 signatures. However, trace element data suggest different petrogeneses for the two suites. The Red Bluff suite is interpreted as having a direct derivation from mantle sources via extended fractional crystallization of basaltic parental magmas, with minor crustal assimilation. The Llano granites appear to represent anatectic melts derived from slightly older, juvenile crustal sources; some melts underwent fractional crystallization controlled by feldspar and accessory minerals. The petrology and geochemistry of ~1.1 Ga granites in Texas indicate that they should not be considered as part of a single \u27anorogenic\u27 magmatic event. The Red Bluff granitic suite was emplaced into a shelf sequence, north of the Grenville Front, within a broad zone characterized by mild extension. In contrast, Llano granites are late-stage intrusions emplaced into multiply deformed and metamorphosed crust, south of the Grenville Front, during or after waning stages of Grenville orogenesis

    Large-angle scattered light measurements for quantum-noise filter cavity design studies

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    Optical loss from scattered light could limit the performance of quantum-noise filter cavities being considered for an upgrade to the Advanced LIGO gravitational-wave detectors. This paper describes imaging scatterometer measurements of the large-angle scattered light from two high-quality sample optics, a high reflector and a beam splitter. These optics are each superpolished fused silica substrates with silica:tantala dielectric coatings. They represent the current state-of-the art optical technology for use in filter cavities. We present angle-resolved scatter values and integrate these to estimate the total scatter over the measured angles. We find that the total integrated light scattered into larger angles can be as small as 4 ppm.Comment: 11 pages, 9 figure

    From the Empire State to the North Star State: Voter Engagement in the 2016 Election

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    Voter engagement has the potential to be a fundamental part of social work practice and key to the professional socialization of social work students. This article describes a classroom-based voter engagement project conducted in two undergraduate social work programs in different U.S. states with significantly different voting laws. We describe the rationale, process of implementing the project, evaluation, and review the results in the context of the 2016 election. We suggest future research that can help develop best practices and methods for implementation of voter engagement in social work practice and education in the future

    The Empirical Evidence for the Telemedicine Intervention in Diabetes Management

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    Objective: The research presented here assesses the scientific evidence for the telemedicine intervention in the management of diabetes (telediabetes), gestational diabetes, and diabetic retinopathy. The impetus derives from the confluence of high prevalence of these diseases, increasing incidence, and rising costs, while telemedicine promises to ameliorate, if not prevent, type 2 diabetes and its complications. Materials and Methods: A purposeful review of the literature identified relevant publications from January 2005 to December 2013. These were culled to retain only credible research articles for detailed review and analysis. The search yielded approximately 17,000 articles with no date constraints. Of these, 770 appeared to be research articles within our time frame. A review of the abstracts yielded 73 articles that met the criteria for inclusion in the final analysis. Evidence is organized by research findings regarding feasibility/acceptance, intermediate outcomes (e.g., use of service, and screening compliance), and health outcomes (control of glycemic level, lipids, body weight, and physical activity.) Results: Definitions of telediabetes varied from study to study vis-à-vis diabetes subtype, setting, technology, staffing, duration, frequency, and target population. Outcome measures also varied. Despite these vagaries, sufficient evidence was obtained from a wide variety of research studies, consistently pointing to positive effects of telemonitoring and telescreening in terms of glycemic control, reduced body weight, and increased physical exercise. The major contributions point to telemedicine's potential for changing behaviors important to diabetes control and prevention, especially type 2 and gestational diabetes. Similarly, screening and monitoring for retinopathy can detect symptoms early that may be controlled or treated. Conclusions: Overall, there is strong and consistent evidence of improved glycemic control among persons with type 2 and gestational diabetes as well as effective screening and monitoring of diabetic retinopathy.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140288/1/tmj.2015.0029.pd

    Function reconstruction as a classical moment problem: A maximum entropy approach

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    We present a systematic study of the reconstruction of a non-negative function via maximum entropy approach utilizing the information contained in a finite number of moments of the function. For testing the efficacy of the approach, we reconstruct a set of functions using an iterative entropy optimization scheme, and study the convergence profile as the number of moments is increased. We consider a wide variety of functions that include a distribution with a sharp discontinuity, a rapidly oscillatory function, a distribution with singularities, and finally a distribution with several spikes and fine structure. The last example is important in the context of the determination of the natural density of the logistic map. The convergence of the method is studied by comparing the moments of the approximated functions with the exact ones. Furthermore, by varying the number of moments and iterations, we examine to what extent the features of the functions, such as the divergence behavior at singular points within the interval, is reproduced. The proximity of the reconstructed maximum entropy solution to the exact solution is examined via Kullback-Leibler divergence and variation measures for different number of moments.Comment: 20 pages, 17 figure

    Creating a Culture of Voting in Direct and Generalist Practice: Training Field Instructors

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    Social workers have an ethical responsibility to be engaged in policy change, regardless of their practice area or specialization. Voter engagement and the importance of political power through voting is often overlooked in the literature as a valid and important component of social work practice. Creating a culture of nonpartisan voter engagement in practice settings can help empower individuals who have been historically and intentionally disenfranchised from our electoral system. Training for field instructors, faculty, and field staff is a key aspect of voter engagement in social work education. Unfortunately, social work education is unlikely to include substantive content on voter engagement or its connection to social work practice and impact. This article presents one component of a model for integrating voter engagement into social work education: the provision of training for field instructors on nonpartisan voter engagement at two universities over two years. Evaluation findings suggest that pre-existing levels of political efficacy affect the reaction of field instructors to nonpartisan voter engagement training. Furthermore, findings indicate that field instructors who receive voter engagement training are more likely to serve as resources for their students and to consider voter engagement as part of their own practice. We offer evidence on the important role field educators can play in the success of the larger national effort to integrate voter engagement in social work education. Increasing awareness of what social workers, nonprofit, and public agencies are allowed--or even required--to do is a critical first step

    Correlation between microstructure and magnetotransport in organic semiconductor spin valve structures

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    We have studied magnetotransport in organic-inorganic hybrid multilayer junctions. In these devices, the organic semiconductor (OSC) Alq3_3 (tris(8-hydroxyquinoline) aluminum) formed a spacer layer between ferromagnetic (FM) Co and Fe layers. The thickness of the Alq3_3 layer was in the range of 50-150 nm. Positive magnetoresistance (MR) was observed at 4.2 K in a current perpendicular to plane geometry, and these effects persisted up to room temperature. The devices' microstructure was studied by X-ray reflectometry, Auger electron spectroscopy and polarized neutron reflectometry (PNR). The films show well-defined layers with modest average chemical roughness (3-5 nm) at the interface between the Alq3_3 and the surrounding FM layers. Reflectometry shows that larger MR effects are associated with smaller FM/Alq3_3 interface width (both chemical and magnetic) and a magnetically dead layer at the Alq3_3/Fe interface. The PNR data also show that the Co layer, which was deposited on top of the Alq3_3, adopts a multi-domain magnetic structure at low field and a perfect anti-parallel state is not obtained. The origins of the observed MR are discussed and attributed to spin coherent transport. A lower bound for the spin diffusion length in Alq3_3 was estimated as 43±543 \pm 5 nm at 80 K. However, the subtle correlations between microstructure and magnetotransport indicate the importance of interfacial effects in these systems.Comment: 21 pages, 11 figures and 2 table
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