326 research outputs found

    The Distribution of the Asymptotic Number of Citations to Sets of Publications by a Researcher or From an Academic Department Are Consistent With a Discrete Lognormal Model

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    How to quantify the impact of a researcher's or an institution's body of work is a matter of increasing importance to scientists, funding agencies, and hiring committees. The use of bibliometric indicators, such as the h-index or the Journal Impact Factor, have become widespread despite their known limitations. We argue that most existing bibliometric indicators are inconsistent, biased, and, worst of all, susceptible to manipulation. Here, we pursue a principled approach to the development of an indicator to quantify the scientific impact of both individual researchers and research institutions grounded on the functional form of the distribution of the asymptotic number of citations. We validate our approach using the publication records of 1,283 researchers from seven scientific and engineering disciplines and the chemistry departments at the 106 U.S. research institutions classified as "very high research activity". Our approach has three distinct advantages. First, it accurately captures the overall scientific impact of researchers at all career stages, as measured by asymptotic citation counts. Second, unlike other measures, our indicator is resistant to manipulation and rewards publication quality over quantity. Third, our approach captures the time-evolution of the scientific impact of research institutions.Comment: 20 pages, 11 figures, 3 table

    Torqued fireballs in relativistic heavy-ion collisions

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    We show that the fluctuations in the wounded-nucleon model of the initial stage of relativistic heavy-ion collisions, together with the natural assumption that the forward (backward) moving wounded nucleons emit particles preferably in the forward (backward) direction, lead to an event-by-event torqued fireball. The principal axes associated with the transverse shape are rotated in the forward region in the opposite direction than in the backward region. On the average, the standard deviation of the relative torque angle between the forward and backward rapidity regions is about 20deg for the central and 10deg for the mid-peripheral collisions. The hydrodynamic expansion of a torqued fireball leads to a torqued collective flow, yielding, in turn, torqued principal axes of the transverse-momentum distributions at different rapidities. We propose experimental measures, based on cumulants involving particles in different rapidity regions, which should allow for a quantitative determination of the effect from the data. To estimate the non-flow contributions from resonance decays we run Monte Carlo simulations with THERMINATOR. If the event-by-event torque effect is found in the data, it will support the assumptions concerning the fluctuations in the early stage of the fireball formation, as well as the hypothesis of the asymmetric rapidity shape of the emission functions of the moving sources in the nucleus-nucleus collisions.Comment: Grant reference adde

    Hemodynamic performance and inflammatory response during the use of VAD-InCor as a bridge to transplant

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    FUNDAMENTO: O transplante cardíaco enfrenta o grave problema da escassez de doadores. Estima-se que entre 20% e 40% dos pacientes falecem na fila de espera. Para esses pacientes, a utilização de dispositivos de assistência circulatória é, muitas vezes, a única possibilidade de sobrevivência durante a espera do doador. No Brasil, não existe nenhum programa regular de utilização desses dispositivos como ponte para transplante. OBJETIVO: Avaliar o desempenho hemodinâmico e a resposta inflamatória durante a utilização do DAV-InCor como ponte para transplante. MÉTODOS: Entre outubro de 2003 e abril de 2006, 11 pacientes, indicados em caráter de prioridade para o transplante cardíaco, evoluíram em choque cardiogênico refratário. O implante do DAV-InCor foi realizado em sete pacientes. O diagnóstico etiológico foi cardiopatia chagásica em cinco pacientes e cardiomiopatia dilatada idiopática em dois. RESULTADOS: A assistência mecânica ao ventrículo esquerdo foi mantida nos sete pacientes por períodos entre 14 e 42 dias (média 26,2). O desempenho hemodinâmico foi adequado, com a normalização do índice cardíaco, dos níveis de saturação venosa de O2 e do lactato. O transplante foi realizado em dois pacientes, os outros cinco faleceram por infecção sistêmica ou falência de múltiplos órgãos. CONCLUSÃO: O desempenho do DAV-Incor, no comportamento hemodinâmico dos pacientes estudados, foi adequado para a manutenção de uma condição circulatória satisfatória durante o período estudado. Houve melhora dos parâmetros de perfusão tecidual e manutenção de sinais de resposta inflamatória sistêmica. Houve alta incidência de complicações; contudo, não foram demonstradas complicações relacionadas ao dispositivo que comprometam a segurança da utilização do mesmo.BACKGROUND: Cardiac transplantation faces the serious problem of lack of donors and it is estimated that 20 to 40% of the patients die while waiting for heart transplantation. For these patients, the use of mechanical circulatory assist devices is the only choice of survival while waiting for a donor. In Brazil, the experience with mechanical circulatory support is limited and there is no regular program regarding the use of these devices as a bridge to heart transplantation. OBJECTIVE: To evaluate the hemodynamic performance and the systemic inflammatory response during the clinical use of the InCor-type ventricular assist device (VAD-InCor) as a bridge to heart transplantation. METHODS: Between October 2003 and April 2006, 11 patients in the waiting list for heart transplantation presented hemodynamic deterioration due to refractory cardiogenic shock. Seven of these patients were submitted to VAD-InCor implantation for left ventricular assistance. The etiologic diagnosis was Chagas' disease in 5 patients and idiopathic dilated cardiomyopathy in 2. RESULTS: The duration of left ventricular assistance ranged from 14 to 42 days (mean 26.2 days). During this period, the hemodynamic performance of the DAV-InCor was adequate to support a normal hemodynamic state. There was normalization of central venous oxygen saturation and serum lactate. Two patients were submitted to heart transplantation, while the other 5 patients died under assistance due to infection and multiple organ failure. CONCLUSION: The performance of the VAD-InCor, in the hemodynamic behavior of the studied patients, was adequate for the maintenance of a satisfactory circulatory state during the studied period. There was improvement in the tissue perfusion parameters and maintenance of systemic inflammatory response signs. There was a high incidence of complications; however, complications related to the device, which could compromise the safety of its use, were not demonstrated.FAPESPCNP

    High-field magnetoresistance of La0.67Sr0.33MnO3 thin films deposited on LiNbO3 substrates

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    Colossal magnetoresistive manganites have been widely studied due to their potential use in sensor and device applications. In this work, La0.67Sr0.33MnO3 thin films were deposited by pulsed laser ablation on LiNbO3 substrates and magnetoresistance measurements were performed using pulsed magnetic fields up to 25 T. The corresponding magnetoconductance of the films was fitted in order to obtain the grain boundary (GB) contribution to the transport properties. The observed temperature dependence of the fitting parameters was indicative of antiferromagnetism across GB spins and reflected the progressive reduction of magnetic ordering with increasing temperature.This work was supported in part by Project No. FEDER/POCTI 155/94 from Fundação para a Ciência e Tecnologia (FCT). I.T. Gomes, A. Pereira and J. Barbosa gratefully acknowledge Ph.D. grants (SFRH/BD/36348/2007, SFRH/BD/22373/2005 and SFRH/BD/41913/2007, respectively) from FCT

    Pharmacogenetics of glucocorticoid replacement could optimize the treatment of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

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    INTRODUCTION: 21-hydroxylase deficiency is an autosomal recessive disorder that causes glucocorticoid deficiency and increased androgen production. Treatment is based on glucocorticoid replacement; however, interindividual variability in the glucocorticoid dose required to achieve adequate hormonal control has been observed. OBJECTIVE: The present study aimed to evaluate the association between polymorphic variants involved inglucocorticoid action and/or metabolism and the mean daily glucocorticoid dose in 21-hydroxylase deficiency patients. METHODS: We evaluated 53 patients with classical forms of 21-hydroxylase deficiency who were receiving cortisone acetate. All patients were between four and six years of age and had normal androgen levels. RESULTS: The P450 oxidoreductase A503V, HSD11B1 rs12086634, and CYP3A7*1C variants were found in 19%, 11.3% and 3.8% of the patients, respectively. The mean ± SD glucocorticoid dose in patients with the CYP3A7*1C and wild-type alleles was 13.9 ± 0.8 and 19.5 ± 3.2 mg/m²/d, respectively. We did not identify an association between the P450 oxidoreductase or HSD11B1 allelic variants and the mean glucocorticoid dose. CONCLUSION: Patients carrying the CYP3A7*1C variant required a significantly lower mean glucocorticoid dose. Indeed, the CYP3A7*1C allele accounted for 20% of the variability in the cortisone acetate dose. The analysis of genes involved in glucocorticoid metabolism may be useful in the optimization of treatment of 21-hydroxylase deficiency

    Nutritional Characterization of Street Food in Urban Turkmenistan, Central Asia

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    ObjectiveDescribing the availability and nutritional composition of the most commonly available street foods in Ashgabat, Turkmenistan. MethodsOne hundred sixty-one street food vending sites (six public markets) were assessed, through a collection of data on vending sites' characteristics and food availability, and samples of commonly available foods (21 homemade; 11 industrial), for chemical analysis. ResultsFruit, beverages, and food other than fruit were available in 6.8, 29.2, and 91.9% of all vending sites, respectively. Regarding the latter, 52.7% of the vending sites sold only homemade products (main dishes, snacks, cakes, biscuits and pastries, bread, ice-cream chocolate and confectionery, savory pastries and sandwiches), 37.2% only industrial (ice-cream, chocolate and confectionery, cakes, biscuits and pastries, snacks, bread and savory pastries) and 10.1% both. Homemade foods presented significantly higher total fat [homemade 11.6 g (range 6.6-19.4 g); industrial 6.2 g (range 4.0-8.6 g), p = 0.001], monounsaturated, polyunsaturated and trans-fat, and sodium and potassium content per serving. Industrial wafers presented the highest mean saturated (11.8 g/serving) and trans-fat (2.32 g/serving) content. Homemade hamburgers presented the highest mean sodium content (1889 mg/serving). ConclusionsStrategies to encourage the production and sales of healthier street foods, especially homemade, are needed to promote healthier urban food environments in urban Turkmenistan

    Availability and Nutritional Composition of Street Food in Urban Central Asia: Findings From Almaty, Kazakhstan

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    Objective: To describe the availability and nutritional composition of commonly available street foods in Almaty, Kazakhstan. Methods: 384 street food vending sites (in 10 public markets) were assessed; information on vending sites characteristics and food availability and samples of the most commonly available street foods (81 homemade; 40 industrial) were collected for chemical analysis. Results: Fruit, beverages and food other than fruit were available in 1.0%, 47.4% and 92.7% of all vending sites. Homemade food other than fruit (e.g., bread, main dishes, snacks, pastries, sandwiches, and cakes) were available in 63.4% of stationary vending sites, while industrial (e.g., snacks, chocolate, cakes, and cookies) in 45.6% of them. Industrial foods were the most energy-dense [median kcal/100 g: 438.8 vs. 267.2, p < 0.001 (homemade)]. Traditional homemade dishes were high in sodium, reaching 2,248 mg/serving (lagman) and major contributors of protein and fat to energy content (shashlik: 22.8% from protein, 68.3% from fat). Industrial chocolate and homemade cake presented the highest saturated (14.6 g/serving) and trans-fat (3.20 g/serving) contents. Conclusion: These findings advocate for the implementation of health promotion strategies targeted at vendors, consumers and other stakeholders. Copyright (c) 2022 Albuquerque, Lança de Morais, Gelormini, Sousa, Casal, Pinho, Damasceno, Moreira, Breda, Lunet and Padrão

    Patterns of Street Food Purchase in Cities From Central Asia

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    Street food makes a significant contribution to the diet of many dwellers in low- and middle-income countries and its trade is a well-developed activity in the central Asian region. However, data on its purchase and nutritional value is still scarce. This study aimed to describe street food purchasing patterns in central Asia, according to time and place of purchase. A multicentre cross-sectional study was conducted in 2016/2017 in the main urban areas of four central Asian countries: Dushanbe (Tajikistan), Bishkek (Kyrgyzstan), Ashgabat (Turkmenistan) and Almaty (Kazakhstan). Street food markets (n = 34) and vending sites (n = 390) were selected by random and systematic sampling procedures. Data on the purchased foods and beverages were collected by direct observation. Time and geographic location of the purchases was registered, and their nutritional composition was estimated. A total of 714 customers, who bought 852 foods, were observed. Customers' influx, buying rate and purchase of industrial food were higher in city centers compared to the outskirts (median: 4.0 vs. 2.0 customers/10 min, p < 0.001; 5.0 vs. 2.0 food items/10 min, p < 0.001; 36.2 vs. 28.7%, p = 0.004). Tea, coffee, bread and savory pastries were most frequently purchased in the early morning, bread, main dishes and savory pastries during lunchtime, and industrial products in the mid-morning and mid-afternoon periods. Energy and macronutrient density was highest at 11:00-12:00 and lowest at 09:00-10:00. Purchases were smaller but more energy-dense in city centers, and higher in saturated and trans-fat in the peripheries. This work provides an overview of the street food buying habits in these cities, which in turn reflect local food culture. These findings from the main urban areas of four low- and middle-income countries which are currently under nutrition transition can be useful when designing public health interventions customized to the specificities of these food environments and their customers

    Análise comparativa entre arranjos de tomografia elétrica no reconhecimento de estruturas de fluxo em aquífero fraturado em Caçapava do Sul (RS)

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    This paper performs presents a comparative analysis between data from detailed electrical resistivity tomography data acquired through the dipole-dipole, Schlumberger and Wenner arrays of detail, obtained on a ground where granite terrain in Caçapava do Sul (RS) where groundwater flows in occurs underground flow in a fractured aquifer system, acquired through the arrangements make dipole-dipole, Schlumberger and Wenner. Structural data obtained on rocks exposed in 100 m and 300 m offrom the study area served as a fundamental the basis for analysisthe analysis of geophysical products and the definition of the mathematical model that is more feasible with the reality. The predominant fracture direction in the region has E/W orientation with two main senses of diving.By the results of the three arrays, it was possible to recognize areas of low resistivity related to water accumulation, with values lower than 70 Ω.m, in contrast to values higher than 1000 Ω.m typical of unaltered rock. The results of the arrangement allowed Schlumberger array allowed a 3D modeling a surface of low resistivity surface with orientation and dive compatible with the fracture system recognized in field, ih this way this array showed a more realist model guidance and diving are compatible with systems of fractures found in rock, to the of the geological structures in detriment to the other results, which do not allow subsidies for an adequate definition of sites for drilling wells. Este trabalho apresenta uma análise comparativa entre dados de tomografia elétrica de detalhe, obtidos sobre terreno granítico onde ocorre fluxo subterrâneo em sistema aquífero fraturado, adquiridos por meio dos arranjos dipolo-dipolo, Schlumberger e Wenner, na região de Caçapava do Sul (RS). Dados estruturais obtidos em exposições de rochas entre 100 m e 300 m da área de estudo serviram de base para análise dos produtos geofísicos e definição do modelo matemático mais factível a realidade geológica. O fraturamento predominante na região possui orientação E/W com dois sentidos principais de mergulho. Nos três arranjos de aquisição tomográfica analisados, foi possível o reconhecimento de zonas de baixa resistividade relacionadas ao acúmulo de água, com valores inferiores a 70 W.m, em contraste com valores superiores a 1000 W.m típicos de rocha inalterada. Os resultados referentes ao arranjo Schlumberger permitiram o modelamento 3D de uma superfície de baixa resistividade com orientação e mergulho compatíveis com sistemas de fraturas reconhecidos em afloramentos, em detrimento aos demais resultados, que não possibilitaram subsídios para uma definição adequada de locais para perfuração de poços
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