8,300 research outputs found

    Immigrant Selection Systems and Occupational Outcomes of International Medical Graduates in Canada and the United States

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    We analyze the process of immigrant selection and occupational outcomes of International Medical Graduates (IMGs) in the US and Canada. We extend the IMG relicensing model of Kugler and Sauer (2005) to incorporate two different approaches to immigrant selection: employer nomination systems and point systems. Analysis of the model indicates that point systems can allow IMGs to immigrate who would be unable to gain entry to the receiving country under an employer nomination system and who are subsequently unable to relicense and work as physicians in the receiving country. We apply the model to the case of IMGs migrating to the US and Canada since the 1960s and evaluate the empirical predictions from the model based on an analysis of the occupational outcomes of IMGs in Canada (where a point system has been in place) and in the US (where IMGs enter through employer nomination). In Canada, IMGs are less likely to be employed as a physician than are IMGs in the US and a large percentage of the IMGs in Canada either find work in lower skill occupations or are not employed. The empirical findings are consistent with our hypotheses based on the theoretical framework on the effects of immigrant selection systems on the probability of working as a physician in the two countries.physicians, immigration, occupation, skills, human capital

    Immigrants in Health Care: Keeping Americans Healthy Through Care and Innovation

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    Immigrants play an outsized and imperative role in the U.S. health care industry. Combining existing data and profiles of immigrants across the health care spectrum, Immigrants in Health Care: Keeping Americans Healthy Through Care and Innovation, published by The Immigrant Learning Center, Inc. (ILC) and the Institute for Immigration Research, a joint venture between George Mason University and The ILC, outlines the impact of the foreign-born in health care as a whole and particularly in three subfields: medicine and medical science, long-term care and nursing. Comprising only 13% of the general population, immigrants are 22% of nursing, psychiatric and home health aides, 28% of physicians and surgeons and 40% of medical scientists in manufacturing research and development. Foreign-born health care workers are critical in meeting the demands of the current health care market, which includes shortages of physicians in rural and inner-city areas, a need for cutting-edge medical technology and an aging and longer-lived population rapidly diversifying in race and ethnicity. Given the necessary innovation and cultural and linguistic skills immigrants bring to health care, the authors recommend creating provisional visas for home care workers, supporting the Professional Access to Health Workforce Integration Act, and investing in and further developing workforce development programs that support and help integrate immigrant health care professionals. (Crystal Ye for The ILC Public Education Institute

    Plug-and-play and coordinated control for bus-connected AC islanded microgrids

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    This paper presents a distributed control architecture for voltage and frequency stabilization in AC islanded microgrids. In the primary control layer, each generation unit is equipped with a local controller acting on the corresponding voltage-source converter. Following the plug-and-play design approach previously proposed by some of the authors, whenever the addition/removal of a distributed generation unit is required, feasibility of the operation is automatically checked by designing local controllers through convex optimization. The update of the voltage-control layer, when units plug -in/-out, is therefore automatized and stability of the microgrid is always preserved. Moreover, local control design is based only on the knowledge of parameters of power lines and it does not require to store a global microgrid model. In this work, we focus on bus-connected microgrid topologies and enhance the primary plug-and-play layer with local virtual impedance loops and secondary coordinated controllers ensuring bus voltage tracking and reactive power sharing. In particular, the secondary control architecture is distributed, hence mirroring the modularity of the primary control layer. We validate primary and secondary controllers by performing experiments with balanced, unbalanced and nonlinear loads, on a setup composed of three bus-connected distributed generation units. Most importantly, the stability of the microgrid after the addition/removal of distributed generation units is assessed. Overall, the experimental results show the feasibility of the proposed modular control design framework, where generation units can be added/removed on the fly, thus enabling the deployment of virtual power plants that can be resized over time

    A decentralized scalable approach to voltage control of DC islanded microgrids

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    We propose a new decentralized control scheme for DC Islanded microGrids (ImGs) composed by several Distributed Generation Units (DGUs) with a general interconnection topology. Each local controller regulates to a reference value the voltage of the Point of Common Coupling (PCC) of the corresponding DGU. Notably, off-line control design is conducted in a Plug-and-Play (PnP) fashion meaning that (i) the possibility of adding/removing a DGU without spoiling stability of the overall ImG is checked through an optimization problem; (ii) when a DGU is plugged in or out at most neighbouring DGUs have to update their controllers and (iii) the synthesis of a local controller uses only information on the corresponding DGU and lines connected to it. This guarantee total scalability of control synthesis as the ImG size grows or DGU gets replaced. Yes, under mild approximations of line dynamics, we formally guarantee stability of the overall closed-loop ImG. The performance of the proposed controllers is analyzed simulating different scenarios in PSCAD.Comment: arXiv admin note: text overlap with arXiv:1405.242

    Immigrant selection systems and occupational outcomes of international medical graduates in Canada and the United States

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    We analyze the process of immigrant selection and occupational outcomes of International Medical Graduates (IMGs) in the US and Canada. We extend the IMG relicensing model of Kugler and Sauer (2005) to incorporate two different approaches to immigrant selection: employer nomination systems and point systems. Analysis of the model indicates that point systems can allow IMGs to immigrate who would be unable to gain entry to the receiving country under an employer nomination system and who are subsequently unable to relicense and work as physicians in the receiving country. We apply the model to the case of IMGs migrating to the US and Canada since the 1960s and evaluate the empirical predictions from the model based on an analysis of the occupational outcomes of IMGs in Canada (where a point system has been in place) and in the US (where IMGs enter through employer nomination). In Canada, IMGs are less likely to be employed as a physician than are IMGs in the US and a large percentage of the IMGs in Canada either find work in lower skill occupations or are not employed. The empirical findings are consistent with our hypotheses based on the theoretical framework on the effects of immigrant selection systems on the probability of working as a physician in the two countries

    Automatic Estimation of Modulation Transfer Functions

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    The modulation transfer function (MTF) is widely used to characterise the performance of optical systems. Measuring it is costly and it is thus rarely available for a given lens specimen. Instead, MTFs based on simulations or, at best, MTFs measured on other specimens of the same lens are used. Fortunately, images recorded through an optical system contain ample information about its MTF, only that it is confounded with the statistics of the images. This work presents a method to estimate the MTF of camera lens systems directly from photographs, without the need for expensive equipment. We use a custom grid display to accurately measure the point response of lenses to acquire ground truth training data. We then use the same lenses to record natural images and employ a data-driven supervised learning approach using a convolutional neural network to estimate the MTF on small image patches, aggregating the information into MTF charts over the entire field of view. It generalises to unseen lenses and can be applied for single photographs, with the performance improving if multiple photographs are available
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