9,948 research outputs found

    Urban Sprawl and the Finances of State and Local Governments

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    Concern over the rate of spatial growth of urban areas has become a significant national political issue and a major development issue in many urban areas. An often cited statistic, typically presented as evidence of sprawl, is that between 1960 and 1990 the urban population in the United States increased by 50 percent while the amount of developed land more than doubled (Benefield et al., 1999).While much has been written about the causes and consequences of sprawl, little attention has been paid to the implications of sprawl for the finances of state and local government. There are at least two possible channels for sprawl to affect the finances of state and local governments. First, if the causes of sprawl include market failures or government policies, there may be a role for governmental corrective action. Second, sprawl may affect the costs of and revenue sources for the public provision of goods and services. This paper considers the potential effects that sprawl might have on the finances of state and local governments and the possible policies that might be adopted to address the causes and consequences of sprawl

    A Search for Hydroxylamine (NH_2OH) toward Select Astronomical Sources

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    Observations of 14 rotational transitions of hydroxylamine (NH_2OH) using the NRAO 12 m telescope on Kitt Peak are reported toward IRC+10216, Orion KL, Orion S, Sgr B2(N), Sgr B2(OH), W3IRS5, and W51M. Although recent models suggest the presence of NH_2OH in high abundance, these observations resulted in non-detection. Upper limits are calculated to be as much as six orders of magnitude lower than those predicted by models. Possible explanations for the lower-than-expected abundance are explored

    Spin-dependent properties of a two-dimensional electron gas with ferromagnetic gates

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    A theoretical prediction of the spin-dependent electron self-energy and in-plane transport of a two-dimensional electron gas in proximity with a ferromagnetic gate is presented. The application of the predicted spin-dependent properties is illustrated by the proposal of a device configuration with two neighboring ferromagnetic gates which produces a magnetoresistance effect on the channel current generated by nonmagnetic source and drain contacts. Specific results are shown for a silicon inversion layer with iron gates. The gate leakage current is found to be beneficial to the spin effects.Comment: 3 pages, 2 figures, Replaced with revised versio

    A new scale to assess the therapeutic relationship in community mental health care: STAR

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    Background. No instrument has been developed specifically for assessing the clinician-patient therapeutic relationship (TR) in community psychiatry. This study aimed to develop a measure of the TR with clinician and patient versions using psychometric principles for test construction. Method. A four-stage prospective study was undertaken, comprising qualitative semi-structured interviews about TRs with clinicians and patients and their assessment of nine established scales for their applicability to community care, administering an amalgamated scale of more than 100 items, followed by Principal Components Analysis (PCA) of these ratings for preliminary scale construction. test-retest reliability of the scale and administering the scale in a new sample to confirm its factorial structure. The sample consisted of patients with severe mental illness and a designated key worker in the care of 17 community mental health teams in England and Sweden. Results. New items not covered by established scales were identified, including clinician helpfulness in accessing services, patient aggression and family interference. The new patient (STAR-P) and clinician scales (STAR-C) each have 12 items comprising three subscales: positive collaboration and positive clinician input in both versions, non-supportive clinician input in the patient version, and emotional difficulties in the clinician version. Test-retest reliability was r = 0(.)76 for STAR-P and r = 0(.)68 for STAR-C. The factorial structure of the new scale was confirmed with a good fit. Conclusions. STAR is a specifically developed, brief scale to assess TRs in community psychiatry with good psychometric properties and is suitable for use in research and routine care

    Time Ordering in Kicked Qubits

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    We examine time ordering effects in strongly, suddenly perturbed two-state quantum systems (kicked qubits) by comparing results with time ordering to results without time ordering. Simple analytic expressions are given for state occupation amplitudes and probabilities for singly and multiply kicked qubits. We investigate the limit of no time ordering, which can differ in different representations.Comment: 26 pages, 5 figure

    Constraints on the Interactions between Dark Matter and Baryons from the X-ray Quantum Calorimetry Experiment

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    Although the rocket-based X-ray Quantum Calorimetry (XQC) experiment was designed for X-ray spectroscopy, the minimal shielding of its calorimeters, its low atmospheric overburden, and its low-threshold detectors make it among the most sensitive instruments for detecting or constraining strong interactions between dark matter particles and baryons. We use Monte Carlo simulations to obtain the precise limits the XQC experiment places on spin-independent interactions between dark matter and baryons, improving upon earlier analytical estimates. We find that the XQC experiment rules out a wide range of nucleon-scattering cross sections centered around one barn for dark matter particles with masses between 0.01 and 10^5 GeV. Our analysis also provides new constraints on cases where only a fraction of the dark matter strongly interacts with baryons.Comment: 15 pages, 9 figures. Extended discussion of methodology, to appear in PR
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