1,586 research outputs found

    Diplomas for Learning, not Seat Time: The Impacts of New York Regents Examinations

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    [Excerpt] New York State has been administering curriculum-based Regents Examinations to high school students ever since June 1878. As Sherman Tinkelman, Assistant Commissioner for Examinations and Scholarships described in a 1966 report: The Regents examinations are closely related to the curriculum in New York State. They are, as you can see, inseparably intertwined. One supports and reinforces the other.... These instruments presuppose and define standards.... They are a strong supervisory and instructional tool-- and deliberately so. They are effective in stimulating good teaching and good learning practices (Tinkelman, 1966 p. 12)

    The Role of the Family in Immigrants' Labor-Market Activity: Evidence from the United States

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    We use Census of Population microdata for 1980 and 1990 to examine the labor supply and wages of immigrant husbands and wives in the United States in a family context. Earlier research by Baker and Benjamin (1997) posits a family investment model in which, upon arrival, immigrant husbands invest in their human capital while immigrant wives work to provide the family with liquidity during this period. Consistent with this model, they find for Canada that immigrant wives work longer hours upon arrival than comparable natives, but, with time in Canada, they are eventually overtaken by native wives. In contrast, we find that, among immigrants to the United States, both husbands and wives work and earn less than comparable natives upon arrival, with similar shortfalls for men and women. Further, both immigrant husbands and wives have similar, positive assimilation profiles in wages and labor supply and eventually overtake both the wages and the labor supply of comparable natives.

    Dynamic and static properties of the invaded cluster algorithm

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    Simulations of the two-dimensional Ising and 3-state Potts models at their critical points are performed using the invaded cluster (IC) algorithm. It is argued that observables measured on a sub-lattice of size l should exhibit a crossover to Swendsen-Wang (SW) behavior for l sufficiently less than the lattice size L, and a scaling form is proposed to describe the crossover phenomenon. It is found that the energy autocorrelation time tau(l,L) for an l*l sub-lattice attains a maximum in the crossover region, and a dynamic exponent z for the IC algorithm is defined according to tau_max ~ L^z. Simulation results for the 3-state model yield z=.346(.002) which is smaller than values of the dynamic exponent found for the SW and Wolff algorithms and also less than the Li-Sokal bound. The results are less conclusive for the Ising model, but it appears that z<.21 and possibly that tau_max ~ log L so that z=0 -- similar to previous results for the SW and Wolff algorithms.Comment: 21 pages with 12 figure

    LaF3 insulators for MIS structures

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    Thin films of Laf3 deposited on Si or GaAs substrates have been observed to form blocking contacts with very high capacitances. This results in comparatively‐hysteresis‐free and sharpC‐V (capacitance‐voltage) characteristics for MIS structures. Such structures have been used to study the interface states of GaAs with increased resolution and to construct improved photocapacitive infrared detectors

    Differences in demographic composition and in work, social, and functional limitations among the populations with unipolar depression and bipolar disorder: results from a nationally representative sample

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    <p>Abstract</p> <p>Background</p> <p>Existing literature on mood disorders suggests that the demographic distribution of bipolar disorder may differ from that of unipolar depression, and also that bipolar disorder may be especially disruptive to personal functioning. Yet, few studies have directly compared the populations with unipolar depressive and bipolar disorders, whether in terms of demographic characteristics or personal limitations. Furthermore, studies have generally examined work-related costs, without fully investigating the extensive personal limitations associated with diagnoses of specific mood disorders. The purpose of the present study is to compare, at a national level, the demographic characteristics, work productivity, and personal limitations among individuals diagnosed with bipolar disorder versus those diagnosed with unipolar depressive disorders and no mood disorder.</p> <p>Methods</p> <p>The Medical Expenditure Panel Survey 2004-2006, a nationally representative survey of the civilian, non-institutionalized U.S. population, was used to identify individuals diagnosed with bipolar disorder and unipolar depressive disorders based on ICD-9 classifications. Outcomes of interest were indirect costs, including work productivity and personal limitations.</p> <p>Results</p> <p>Compared to those with depression and no mood disorder, higher proportions of the population with bipolar disorder were poor, living alone, and not married. Also, the bipolar disorder population had higher rates of unemployment and social, cognitive, work, and household limitations than the depressed population. In multivariate models, patients with bipolar disorder or depression were more likely to be unemployed, miss work, and have social, cognitive, physical, and household limitations than those with no mood disorder. Notably, findings indicated particularly high costs for bipolar disorder, even beyond depression, with especially large differences in odds ratios for non-employment (4.6 for bipolar disorder versus 1.9 for depression, with differences varying by gender), social limitations (5.17 versus 2.85), cognitive limitations (10.78 versus 3.97), and work limitations (6.71 versus 3.19).</p> <p>Conclusion</p> <p>The bipolar disorder population is distinctly more vulnerable than the population with depressive disorder, with evidence of fewer personal resources, lower work productivity, and greater personal limitations. More systematic analysis of the availability and quality of care for patients with bipolar disorder is encouraged to identify effectively tailored treatment interventions and maximize cost containment.</p

    Optimising paediatric afferent component early warning systems : a hermeneutic systematic literature review and model development

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    Objective: To identify the core components of successful early warning systems for detecting and initiating action in response to clinical deterioration in paediatric inpatients. Methods: A hermeneutic systematic literature review informed by translational mobilisation theory and normalisation process theory was used to synthesise 82 studies of paediatric and adult early warning systems and interventions to support the detection of clinical deterioration and escalation of care. This method, which is designed to develop understanding, enabled the development of a propositional model of an optimal afferent component early warning system. Results: Detecting deterioration and initiating action in response to clinical deterioration in paediatric inpatients involves several challenges, and the potential failure points in early warning systems are well documented. Track and trigger tools (TTT) are commonly used and have value in supporting key mechanisms of action but depend on certain preconditions for successful integration into practice. Several supplementary interventions have been proposed to improve the effectiveness of early warning systems but there is limited evidence to recommend their wider use, due to the weight and quality of the evidence; the extent to which systems are conditioned by the local clinical context; and the need to attend to system component relationships, which do not work in isolation. While it was not possible to make empirical recommendations for practice, the review methodology generated theoretical inferences about the core components of an optimal system for early warning systems. These are presented as a propositional model conceptualised as three subsystems: detection, planning and action. Conclusions: There is a growing consensus of the need to think beyond TTTs in improving action to detect and respond to clinical deterioration. Clinical teams wishing to improve early warning systems can use the model to consider systematically the constellation of factors necessary to support detection, planning and action and consider how these arrangements can be implemented in their local context

    Vortex Dynamics in Selfdual Maxwell-Higgs Systems with Uniform Background Electric Charge Density

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    We introduce selfdual Maxwell-Higgs systems with uniform background electric charge density and show that the selfdual equations satisfied by topological vortices can be reduced to the original Bogomol'nyi equations without any background. These vortices are shown to carry no spin but to feel the Magnus force due to the shielding charge carried by the Higgs field. We also study the dynamics of slowly moving vortices and show that the spin-statistics theorem holds to our vortices.Comment: 24 pages + 2 figures ( not included), Cu-TP-611, IASSNS-HEP-93/33, NSF-ITP-93-13

    The equation of state of solid nickel aluminide

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    The pressure-volume-temperature equation of state of the intermetallic compound NiAl was calculated theoretically, and compared with experimental measurements. Electron ground states were calculated for NiAl in the CsCl structure, using density functional theory, and were used to predict the cold compression curve and the density of phonon states. The Rose form of compression curve was found to reproduce the ab initio calculations well in compression but exhibited significant deviations in expansion. A thermodynamically-complete equation of state was constructed for NiAl. Shock waves were induced in crystals of NiAl by the impact of laser-launched Cu flyers and by launching NiAl flyers into transparent windows of known properties. The TRIDENT laser was used to accelerate the flyers to speeds between 100 and 600m/s. Point and line-imaging laser Doppler velocimetry was used to measure the acceleration of the flyer and the surface velocity history of the target. The velocity histories were used to deduce the stress state, and hence states on the principal Hugoniot and the flow stress. Flyers and targets were recovered from most experiments. The effect of elasticity and plastic flow in the sample and window was assessed. The ambient isotherm reproduced static compression data very well, and the predicted Hugoniot was consistent with shock compression data

    The MacGyver effect: alive and well in health services research?

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    <p>Abstract</p> <p>Background</p> <p>In a manner similar to the television action hero MacGyver, health services researchers need to respond to the pressure of unpredictable demands and constrained time frames. The results are often both innovative and functional, with the creation of outputs that could not have been anticipated in the initial planning and design of the research.</p> <p>Discussion</p> <p>In the conduct of health services research many challenges to robust research processes are generated as a result of the interface between academic research, health policy and implementation agendas. Within a complex and rapidly evolving environment the task of the health services researcher is, therefore, to juggle sometimes contradictory pressures to produce valid results.</p> <p>Summary</p> <p>This paper identifies the MacGyver-type dilemmas which arise in health services research, wherein innovation may be called for, to maintain the intended scientific method and rigour. These 'MacGyver drivers' are framed as opposing issues from the perspective of both academic and public policy communities. The ideas expressed in this paper are illustrated by four examples from research projects positioned at the interface between public policy strategy and academia.</p
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