9,366 research outputs found

    High-resolution imaging spectroscopy of two micro-pores and an arch filament system in a small emerging-flux region

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    Aims. The purpose of this investigation is to characterize the temporal evolution of an emerging flux region, the associated photospheric and chromospheric flow fields, and the properties of the accompanying arch filament system. Methods. This study is based on imaging spectroscopy with the G\"ottingen Fabry-P\'erot Interferometer at the Vacuum Tower Telescope, on 2008 August 7. Cloud model (CM) inversions of line scans in the strong chromospheric absorption Hα\alpha line yielded CM parameters, which describe the cool plasma contained in the arch filament system. Results. The observations cover the decay and convergence of two micro-pores with diameters of less than one arcsecond and provide decay rates for intensity and area. The photospheric horizontal flow speed is suppressed near the two micro-pores indicating that the magnetic field is sufficiently strong to affect the convective energy transport. The micro-pores are accompanied by an arch filament system, where small-scale loops connect two regions with Hα\alpha line-core brightenings containing an emerging flux region with opposite polarities. The chromospheric velocity of the cloud material is predominantly directed downwards near the footpoints of the loops with velocities of up to 12 km/s, whereas loop tops show upward motions of about 3 km/s. Conclusions. Micro-pores are the smallest magnetic field concentrations leaving a photometric signature in the photosphere. In the observed case, they are accompanied by a miniature arch filament system indicative of newly emerging flux in the form of Ω\Omega-loops. Flux emergence and decay take place on a time-scale of about two days, whereas the photometric decay of the micro-pores is much more rapid (a few hours), which is consistent with the incipient submergence of Ω\Omega-loops. The results are representative for the smallest emerging flux regions still recognizable as such.Comment: 15 pages, 16 figures, 3 tables, published in A&

    Venezuela’s Growth Experience

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    The standard of living, measured as gross domestic product (GDP) per capita, increased dramatically in Venezuela relative to that of the United States from 20 percent in 1920 to 90 percent in 1958, but since then has collapsed to around 30 percent nowadays. What explains these remarkable growth and collapse episodes? Using a standard development accounting framework, we show that the growth episode is mainly accounted for by an increase in capital accumulation and knowledge transfer associated with the foreign direct investment in the booming oil industry. The collapse episode is accounted for equally by a fall in total factor productivity and in capital accumulation. We analyze Venezuela during the collapse episode in the context of a model of heterogeneous production units were policies and institutions favour unproductive in detriment of more productive activities. These policies generate misallocation, lower TFP, and a decline in capital accumulation. We show in the context of an heterogeneous-establishment growth model that distortionary policies can explain a large portion of the current differences in TFP, capital accumulation, and income per capita between Venezuela and the United States.Productivity, physical capital, misallocation, policies

    Venezuela's Growth Experience

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    The standard of living, measured as gross domestic product (GDP) per capita, increased dramatically in Venezuela relative to that of the United States from 20 percent in 1920 to 90 percent in 1958, but since then has collapsed to around 30 percent nowadays. What explains these remarkable growth and collapse episodes? Using a standard development accounting framework, we show that the growth episode is mainly accounted for by an increase in capital accumulation and knowledge transfer associated with the foreign direct investment in the booming oil industry. The collapse episode is accounted for equally by a fall in total factor productivity and in capital accumulation. We analyze Venezuela during the collapse episode in the context of a model of heterogeneous production units were policies and institutions favour unproductive in detriment of more productive activities. These policies generate misallocation, lower TFP, and a decline in capital accumulation. We show in the context of an heterogeneous-establishment growth model that distortionary policies can explain between 80 to 95 percent of the current differences in TFP, capital accumulation, and income per capita between Venezuela and the United States.Productivity, physical capital, misallocation, policies

    The meaning of different forms of structural myocardial injury, immune response and timing of infarct necrosis and cardiac repair

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    Although a decline in the all-cause and cardiac mortality rates following myocardial infarction (MI) during the past 3 decades has been reported, MI is a major cause of death and disability worldwide. From a pathological point of view MI consists in a particular myocardial cell death due to prolonged ischemia. After the onset of myocardial ischemia, cell death is not immediate, but takes a finite period of time to develop. Once complete myocytes’ necrosis has occurred, a process leading to a healed infarction takes place. In fact, MI is a dynamic process that begins with the transition from reversible to irreversible ischemic injury and culminates in the replacement of dead myocardium by a fibrous scar. The pathobiological mechanisms underlying this process are very complex, involving an inflammatory response by several pathways, and pose a major challenge to ability to improve our knowledge. An improved understanding of the pathobiology of cardiac repair after MI and further studies of its underlying mechanisms provide avenues for the development of future strategies directed toward the identification of novel therapies. The chronologic dating of MI is of great importance both to clinical and forensic investigation, that is, the ability to create a theoretical timeline upon which either clinicians or forensic pathologists may increase their ability to estimate the time of MI. Aging of MI has very important practical implications in clinical practice since, based on the chronological dating of MI, attractive alternatives to solve therapeutic strategies in the various phases of MI are developing

    A simple variational method for calculating energy and quantum capacitance of an electron gas with screened interactions

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    We describe a variational procedure for calculating the energy of an electron gas in which the long-range Coulomb interaction is truncated by the screening effect of a nearby metallic gate. We use this procedure to compute the quantum capacitance of the system as a function of electron density and spin polarization. The accuracy of the method is verified against published Monte-Carlo data. The results compare favorably with a recent experiment.Comment: 4 pages, 3 figure

    Marketing of Information Resources in Nigeria: Strategies and Challenges

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    In a country where reading culture is poor, that is, where majority of the inhabitants do not find anything fascinating in reading, even for pleasure, marketing of Information or Information Resources is undoubtedly, a herculean task.  Marketing in this context, is the activity of presenting, advertising and selling Information or Information Resources (product) in the best possible way or ways to the people.  In marketing, the product you intend to sell must have, at least, potential buyers. Realizing the poor attitude of Nigerians towards reading, identifying the best way to marketing Information Resources to them is the primary focus of this paper.  The paper begins with the definitions of the key concepts, marketing, information and Information Resources.  It dwells more on discussing the processes of marketing viz-a-viz their potentials in creating interest in reading by the people.  The paper closes with, highlighting the best strategies by which people could be made to buy information Resources, both human and material

    Implementing a Home-Based Blood Pressure Monitoring Program to Improve Hypertension Management

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    Hypertension is a major problem in the United States. It is critical to identify effective strategies to treat and manage hypertension. An experimental design was utilized to determine the effectiveness of home-based blood pressure monitoring (HBPM) in the management of prehypertension, newly diagnosed, or uncontrolled hypertension. A randomized convenience sample of 20 adults was recruited into a control (n=9) and experimental (n=11) group. The translational care project was conducted over 60 days where participants measured their blood pressures as instructed for the intervention and control groups. An independent t-test was conducted to analyze the effectiveness of HBPM on the participants’ blood pressure, blood pressure knowledge, self-care, and medication adherence utilizing subsequent scales. There was a statistically insignificant increase in systolic blood pressure, but a statistically significant increase in diastolic blood pressure between the experimental and control groups at 60 days. There was no statistical significance in the improvement of HBPM adherence, knowledge, self-care, or medication adherence between the two groups at 60 days. While there is limited statistical support for this translational research project, other resources support HBPM as an innovative program that has the potential to provide healthcare providers an avenue for more timely, effective, and individualized patient care. Literature demonstrates that improved blood pressure control has the potential to decrease the prevalence of co-morbid conditions and decrease health care costs. With an increase in successful studies legislation could be challenged to increase coverage and reimbursement cost for blood pressure monitors and more HBPM programs in practice. Continued research related to HBPM and patient adherence is necessary to improve patient access to affordable care and overall self-care outcomes
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