996 research outputs found

    Oxford Handbook Of American Political Development

    Get PDF
    Scholars working in or sympathetic to American political development (APD) share a commitment to accurately understanding the history of American politics – and thus they question stylized facts about America’s political evolution. Like other approaches to American politics, APD prizes analytical rigor, data collection, the development and testing of theory, and the generation of provocative hypotheses. Much APD scholarship indeed overlaps with the American politics subfield and its many well developed literatures on specific institutions or processes (for example Congress, judicial politics, or party competition), specific policy domains (welfare policy, immigration), the foundations of (in)equality in American politics (the distribution of wealth and income, race, ethnicity, gender, class, and sexual and gender orientation), public law, and governance and representation. What distinguishes APD is careful, systematic thought about the ways that political processes, civic ideals, the political construction of social divisions, patterns of identity formation, the making and implementation of public policies, contestation over (and via) the Constitution, and other formal and informal institutions and processes evolve over time – and whether (and how) they alter, compromise, or sustain the American liberal democratic regime. APD scholars identify, in short, the histories that constitute American politics. They ask: what familiar or unfamiliar elements of the American past illuminate the present? Are contemporary phenomena that appear new or surprising prefigured in ways that an APD approach can bring to the fore? If a contemporary phenomenon is unprecedented then how might an accurate understanding of the evolution of American politics unlock its significance

    ArCLight - a Compact Dielectric Large-Area Photon Detector

    Get PDF
    ArCLight is a novel device for detecting scintillation light over large areas with Photon Detection Efficiency (PDE) of the order of a few percent. Its robust technological design allows for efficient use in large-volume particle detectors, such as Liquid Argon Time Projection Chambers (LArTPCs) or liquid scintillator detectors. Due to its dielectric structure it can be placed inside volumes with high electric field. It could potentially replace vacuum PhotoMultiplier Tubes (PMTs) in applications where high PDE is not required. The photon detection efficiency for a 10x10cm2 detector prototype was measured to be in the range of 0.8% to 2.2% across the active area

    Autonomous frequency domain identification: Theory and experiment

    Get PDF
    The analysis, design, and on-orbit tuning of robust controllers require more information about the plant than simply a nominal estimate of the plant transfer function. Information is also required concerning the uncertainty in the nominal estimate, or more generally, the identification of a model set within which the true plant is known to lie. The identification methodology that was developed and experimentally demonstrated makes use of a simple but useful characterization of the model uncertainty based on the output error. This is a characterization of the additive uncertainty in the plant model, which has found considerable use in many robust control analysis and synthesis techniques. The identification process is initiated by a stochastic input u which is applied to the plant p giving rise to the output. Spectral estimation (h = P sub uy/P sub uu) is used as an estimate of p and the model order is estimated using the produce moment matrix (PMM) method. A parametric model unit direction vector p is then determined by curve fitting the spectral estimate to a rational transfer function. The additive uncertainty delta sub m = p - unit direction vector p is then estimated by the cross spectral estimate delta = P sub ue/P sub uu where e = y - unit direction vectory y is the output error, and unit direction vector y = unit direction vector pu is the computed output of the parametric model subjected to the actual input u. The experimental results demonstrate the curve fitting algorithm produces the reduced-order plant model which minimizes the additive uncertainty. The nominal transfer function estimate unit direction vector p and the estimate delta of the additive uncertainty delta sub m are subsequently available to be used for optimization of robust controller performance and stability

    Charges of twisted branes: the exceptional cases

    Full text link
    The charges of the twisted D-branes for the two exceptional cases (SO(8) with the triality automorphism and E_6 with charge conjugation) are determined. To this end the corresponding NIM-reps are expressed in terms of the fusion rules of the invariant subalgebras. As expected the charge groups are found to agree with those characterising the untwisted branes.Comment: 15 page

    Sorption and catalytic oxidation of Fe(II) at the surface of calcite

    Get PDF
    The effect of sorption and coprecipitation of Fe(II) with calcite on the kinetics of Fe(II) oxidation was investigated. The interaction of Fe(II) with calcite was studied experimentally in the absence and presence of oxygen. The sorption of Fe(II) on calcite occurred in two distinguishable steps: (a) a rapid adsorption step (seconds–minutes) was followed by (b) a slower incorporation (hours–weeks). The incorporated Fe(II) could not be remobilized by a strong complexing agent (phenanthroline or ferrozine) but the dissolution of the outmost calcite layers with carbonic acid allowed its recovery. Based on results of the latter dissolution experiments, a stoichiometry of 0.4 mol% Fe:Ca and a mixed carbonate layer thickness of 25 nm (after 168 h equilibration) were estimated. Fe(II) sorption on calcite could be successfully described by a surface adsorption and precipitation model (Comans & Middelburg, GCA51 (1987), 2587) and surface complexation modeling (Van Cappellen et al., GCA57 (1993), 3505; Pokrovsky et al., Langmuir16 (2000), 2677). The surface complex model required the consideration of two adsorbed Fe(II) surface species, >CO3Fe+ and >CO3FeCO3H0. For the formation of the latter species, a stability constant is being suggested. The oxidation kinetics of Fe(II) in the presence of calcite depended on the equilibration time of aqueous Fe(II) with the mineral prior to the introduction of oxygen. If pre-equilibrated for >15 h, the oxidation kinetics was comparable to a calcite-free system (t1/2 = 145 ± 15 min). Conversely, if Fe(II) was added to an aerated calcite suspension, the rate of oxidation was higher than in the absence of calcite (t1/2 = 41 ± 1 min and t1/2 = 100 ± 15 min, respectively). This catalysis was due to the greater reactivity of the adsorbed Fe(II) species, >CO3FeCO3H0, for which the species specific rate constant was estimated

    The "Multimat" experiment at CERN HiRadMat facility: advanced testing of novel materials and instrumentation for HL-LHC collimators

    Get PDF
    The increase of the stored beam energy in future particle accelerators, such as the HL-LHC and the FCC, calls for a radical upgrade in the design, materials and instrumentation of Beam Intercepting Devices (BID), such as collimators Following successful tests in 2015 that validated new composite materials and a novel jaw design conceived for the HL-LHC collimators, a new HiRadMat experiment, named “HRMT36-MultiMat”, is scheduled for autumn 2017. Its objective is to determine the behaviour under high intensity proton beams of a broad range of materials relevant for collimators and beam intercepting devices, thin-film coatings and advanced equipment. The test bench features 16 separate target stations, each hosting various specimens, allowing the exploration of complex phenomena such as dynamic strength, internal damping, nonlinearities due to anisotropic inelasticity and inhomogeneity, effects of energy deposition and radiation on coatings. This paper details the main technical solutions and engineering calculations for the design of the test bench and of the specimens, the candidate target materials and the instrumentation system

    The development of a business intelligence web application to support the decision-making process regarding absenteeism in the workplace

    Get PDF
    Nowadays, one of the biggest concerns of industries all over the world is situations regarding absenteeism, since it has a great impact on the productivity and economy of companies, as well as on the health of their employees. The major causes of absenteeism appear to be work accidents and sickness leaves, which lead to the attempt by companies of understanding how the workload is related to the health of their collaborators and, consequently, to absenteeism. Thus, this paper proposes the design and development of a Web Application based on Business Intelligence indicators in order to help the health and human resources professionals of a Portuguese company analyse the relation between absenteeism and the health and lifestyle of employees, with the intention of concluding whether the work executed on the company is harming workers’ health. Furthermore, it is intended to discover the principal motives for the numerous and more frequent absences in this company, so that it is possible to decrease the absenteeism rate and, hence, improve the decision-making process. This platform will also provide higher quality healthcare and the possibility to find patterns in the absence of collaborators, as well as reduce time-waste and errors.This work has been supported by FCT –Fundação para a CiĂȘncia e Tecnologia within the Project Scope: UID/CEC/00319/201

    Evaluation of rK39 rapid diagnostic tests for canine visceral leishmaniasis : longitudinal study and meta-analysis

    Get PDF
    Canine visceral leishmaniasis is a vector-borne disease caused by the intracellular parasite Leishmania infantum. It is an important veterinary disease, and dogs are also the main animal reservoir for human infection. The disease is widespread in the Mediterranean area, and parts of Asia and South and Central America, and is potentially fatal in both dogs and humans unless treated. Diagnosis of canine infections requires serological or molecular tests. Detection of infection in dogs is important prior to treatment, and in epidemiological studies and control programmes, and a sensitive and specific rapid diagnostic test would be very useful. Rapid diagnostic tests (RDTs) have been developed, but their diagnostic performance has been reported to be variable. We evaluated the sensitivity of a RDT based on serological detection of the rK39 antigen in a cohort of naturally infected Brazilian dogs. The sensitivity of the test to detect infection was relatively low, but increased with time since infection and the severity of infection. We then carried out a meta-analysis of published studies of rK39 RDTs, evaluating the sensitivity to detect disease and infection. The results suggest that rK39 RDTs may be useful in a veterinary clinical setting, but the sensitivity to detect infection is too low for operational control programmes

    Carisbamate Blockade of T-Type Voltage-Gated Calcium Channels

    Get PDF
    Objectives Carisbamate (CRS) is a novel monocarbamate compound that possesses antiseizure and neuroprotective properties. However, the mechanisms underlying these actions remain unclear. Here, we tested both direct and indirect effects of CRS on several cellular systems that regulate intracellular calcium concentration [Ca2+]i. Methods We used a combination of cellular electrophysiologic techniques, as well as cell viability, Store Overload‐Induced Calcium Release (SOICR), and mitochondrial functional assays to determine whether CRS might affect [Ca2+]i levels through actions on the endoplasmic reticulum (ER), mitochondria, and/or T‐type voltage‐gated Ca2+ channels. Results In CA3 pyramidal neurons, kainic acid induced significant elevations in [Ca2+]i and long‐lasting neuronal hyperexcitability, both of which were reversed in a dose‐dependent manner by CRS. Similarly, CRS suppressed spontaneous rhythmic epileptiform activity in hippocampal slices exposed to zero‐Mg2+ or 4‐aminopyridine. Treatment with CRS also protected murine hippocampal HT‐22 cells against excitotoxic injury with glutamate, and this was accompanied by a reduction in [Ca2+]i. Neither kainic acid nor CRS alone altered the mitochondrial membrane potential (Δι) in intact, acutely isolated mitochondria. In addition, CRS did not affect mitochondrial respiratory chain activity, Ca2+‐induced mitochondrial permeability transition, and Ca2+ release from the ER. However, CRS significantly decreased Ca2+ flux in human embryonic kidney tsA‐201 cells transfected with Cav3.1 (voltage‐dependent T‐type Ca2+) channels. Significance Our data indicate that the neuroprotective and antiseizure activity of CRS likely results in part from decreased [Ca2+]i accumulation through blockade of T‐type Ca2+ channels

    Design and construction of the MicroBooNE Cosmic Ray Tagger system

    Get PDF
    The MicroBooNE detector utilizes a liquid argon time projection chamber (LArTPC) with an 85 t active mass to study neutrino interactions along the Booster Neutrino Beam (BNB) at Fermilab. With a deployment location near ground level, the detector records many cosmic muon tracks in each beam-related detector trigger that can be misidentified as signals of interest. To reduce these cosmogenic backgrounds, we have designed and constructed a TPC-external Cosmic Ray Tagger (CRT). This sub-system was developed by the Laboratory for High Energy Physics (LHEP), Albert Einstein center for fundamental physics, University of Bern. The system utilizes plastic scintillation modules to provide precise time and position information for TPC-traversing particles. Successful matching of TPC tracks and CRT data will allow us to reduce cosmogenic background and better characterize the light collection system and LArTPC data using cosmic muons. In this paper we describe the design and installation of the MicroBooNE CRT system and provide an overview of a series of tests done to verify the proper operation of the system and its components during installation, commissioning, and physics data-taking
    • 

    corecore