252 research outputs found

    Ice volume changes of Ariebreen, Spitsbergen, during 1936-1990-2007

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    Ariebreen (77º 01' N, 15º 29' E) is a small valley glacier (ca. 0.36 km2 in August 2007) located at Hornsund, Spitsbergen, Svalbard, ca. 2.5 km to the west of Hornsund Polish Polar Station. Many Svalbard glaciers have experienced a significant recession at least since the 1930s, and most likely since the end of Little Ice Age in the early 20th century (Werner, 1993). It has manifested as thinning and retreating of ice fronts, though a simultaneous thickening at the uppermost elevations in many locations has been reported (Bamber et al., 2004; Nuth et al., 2007). Moreover, the thinning rate of western Svalbard glaciers has shown an acceleration during the most recent decades (Kohler et al., 2007). The main aims of this contribution are to determine whether Ariebreen follows such retreat pattern and to quantify the retreat it has experienced, in terms of area, thickness and volume changes, to estimate the average mass balance equivalent to the ice volume change during the period under investigation, and to estimate the volume of ice presently stored in Ariebreen. The main tools to accomplish this will be the analysis of digital terrain models (DTM) of the glacier surface corresponding to different dates, and the radio-echo sounding of the ice body to determine the present ice volume. The latter is described in a separate contribution to this workshop (Navarro et al., 2008)

    The ten most cited articles of the journal “Nutricion Hospitalaria”

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    Después de 36 años de publicación ininterrumpida de la revista Nutrición Hospitalaria, hemos recopilado los diez artículos más citados. Se muestra también la relación de los diez artículos con más citas a escala mundial; asimismo se estratifican las citaciones según el idioma, inglés o español, la temática o los años analizados. Nutr. Hosp. es, a nivel mundial, la revista de nutrición ibero-latinoamericana mejor valorada. Por el volumen de artículos publicados, con 369 ítems citables en 2014, Nutr Hosp se sitúa en cuarto lugar de todas las revistas de nutrición. Permitir la publicación de artículos en inglés o hacerlo simultáneamente en castellano y en inglés, así como estar en régimen de “Open Access” sin restricción de ningún tipo en la difusión desde el momento de aparición de los artículos, son probablemente elementos favorecedores de las citas.After 36 years of continued publication of the journal Nutrición Hospitalaria, a list with the ten most cited articles published in it is elaborated. The top ten most cited articles in the world literature and stratification according to language, English or Spanish, subject, or period of time published are also analyzed. Nutr Hosp is the most important Ibero latin American nutrition journal. Nutr Hosp published 369 items in 2014 gaining the fourth position among all the world’s journals devoted to nutrition. Article publication in English, or simultaneously in Spanish and English and Open Access policy probably benefit the number of citations

    Intrinsic value of the impact factor of scientific journals

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    Se analiza el porqué de las citaciones de los artículos. Se realizan también algunas consideraciones sobre el factor de impacto de las revistas, sus ventajas y sus posibles defectos. El factor de impacto de las revistas, desde su popularización por el Institute for Scientific Information, ha tomado una gran importancia como parámetro objetivo de evaluación de las revistas científicas y, por extensión, de todo lo que las rodea. No hay correlación con el desfase en factores de impacto de algunas revistas anglosajonas y el de las revistas escritas en otros idiomas. Probablemente se benefician de publicar en inglés y del llamado “efecto Mateo”, según el cual los investigadores científicos eminentes cosechan aplausos mucho más nutridos que otros investigadores, menos conocidos, por contribuciones equivalentes. Es paradójico también que los grandes descubrimientos de nuestra época no figuren entre los 100 artículos más citados. No hay tampoco una correlación entre todos los artículos aparecidos en una publicación y su factor de impacto; la mitad de los artículos de una revista son citados diez veces más que la otra mitad. Los artículos citados 0 veces reciben el mérito de los mejores. Lo ortodoxo sería utilizar en cada artículo el número de citas que recibe, que sería su propio factor de impacto y, para los autores, el índice H.The reason of higher number of citations of some articles is discussed. Some considerations about the journals’ impact factor, its merits and its pitfalls are also made. Scientific journals’ impact factor, popularized by the Institute for Scientific Information, has become an objective parameter for authors’ evaluation and also for institutions and other related circumstances. There is no reason for the impact factor’s gap between some English journals and those written in other languages. English journals probably benefit of the “Mathew’s effect”, according to which eminent scientists are more rewarded by similar contributions than others less known. It is paradoxical that most of the major achievements of our age do not appear among the 100 most cited articles. There is no homogeneity among all the articles appearing in each scientific journal: half of the articles are cited ten times more than the other half. However, those articles cited 0 times are credited like the better ones. Each article should be evaluated by its own citations, which would be its impact factor; the authors should be evaluated by their H index

    Analysis and simulation of multiplexed single-bus networks with and without buffering

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    Performance issues of a single-bus interconnection network for multiprocessor systems, operating in a multiplexed way, are presented in this paper. Several models are developed and used to allow system performance evaluation. Comparisons with equivalent crossbar systems are provided. It is shown how crossbar EBW values can be reached and exceeded when appropriate operation parameters are chosen in a multiplexed single-bus system. Another architectural feature is considered, concerning the utilization of buffers at the memory modules. With the buffering scheme, memory interference can be reduced so that the system performance is practically improved.Peer ReviewedPostprint (published version

    Overlapping communication and computation by using a hybrid MPI/SMPSs approach

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    A previous version of this document was submitted for publication by october 2008.Communication overhead is one of the dominant factors that affect performance in high-performance computing systems. To reduce the negative impact of communication, programmers overlap communication and computation by using asynchronous communication primitives. This increases code complexity, requiring more effort to write parallel code and making less readable code. This paper presents the hybrid use of MPI and SMPSs (SMP superscalar), a task-based shared-memory programming model, enhanced with a restart mechanism allowing the programmer to introduce the asynchronism that is necessary to enable the effective communication/computation overlap in a productive way. We demonstrate the hybrid use of MPI/SMPSs with the high-performance LINPACK benchmark, which uses the lookahead technique to overlap communication and computation. MPI/SMPSs improves the performance of a pure MPI with look-ahead by 7,6% on a 1024 processors machine. In addition to better performance, hybrid MPI/SMPSs substantially reduces code complexity, it is less sensitive to network bandwidth and operating system noise, and improves the use of main memory.Postprint (published version

    Preliminary Study on the Effect of an Early Physical Therapy Intervention after Sentinel Lymph Node Biopsy: A Multicenter Non-Randomized Controlled Trial

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    Selective sentinel lymph node biopsy (SLNB) represents a minimally invasive surgery in patients with breast cancer. The purpose of this study was to explore the possible effect of an early physiotherapy intervention for the recovery of the upper limb and the surgical scars after SLNB in comparison with usual care. A total of 40 patients were enrolled in either the control group (n = 20) or the experimental group (n = 20). The intervention group performed an early physiotherapy program based on functional exercises, scar manual therapy, and educational tips. The control group received usual care. Shoulder range of motion (ROM), grip strength, upper limb pain and disability (SPADI), scar recovery (POSAS), myofascial adhesions (MAP-BC), quality of life (EORTCQLA-BR-23) and the presence of axillary web syndrome (AWS) and lymphoedema were assessed at baseline and immediately after intervention. A follow-up period of 6 months was performed for lymphoedema surveillance. Between groups significant differences in favor of the intervention were found for ROM (r = 0.43), grip strength (r = 0.32), SPADI (d = 0.45), POSAS (d = 1.28), MAP-BC (d = 1.82) and EORTCQLQ-BR 23 general function subscale (d = 0.37) (p < 0.05 for all variables). Our results suggest that an early physical therapy program seems to be more effective than usual care in women after SLNB. However, results should be interpreted with caution and future randomized trial with a larger sample size is neededThis research was partially supported by ICPFA. Grant number 04722/19P/MA. The funder had no role in the design of the study and collection, analysis, and interpretation of data, and in writing the manuscript. Partial funding for open access charge: Universidad de Málag

    Ground-penetrating radar surveys and ice volume estimates of Wedel Jarlsberg Land glaciers, Svalbard

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    We present volume calculations, with detailed error estimates, for eight glaciers on Wedel Jarlsberg Land, southern Spitsbergen, Svalbard, and compare them to those obtained from area-volume scaling relationships. The volume estimates are based upon a dense net of GPR-retrieved ice thickness data collected over several field campaigns spanning the period 2004-2011

    Ice volume estimates from ground-penetrating radar surveys, Wedel Jarlsberg Land glaciers, Svalbard

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    One of the aims of the SvalGlac project is to obtain an improved estimate, with reliable error estimates, of the volume of Svalbard glaciers and their potential contribution to sea level rise. As part of this work, we present volume calculations, with detailed error estimates, for eight glaciers on Wedel Jarlsberg Land, southern Spitsbergen, Svalbard. The volume estimates are based upon a dense net of GPR-retrieved ice thickness data collected over several field campaigns spanning the period 2004-2011. The total area and volume of the ensemble are 502.9±18.6 km2 and 80.72±2.85 km3, respectively. Excluding Ariebreen (a tiny glacier, menor que 0.4 km2 in area), the individual areas, volumes and average ice thickness lie within 4.7-141.0 km2, 0.30-25.85 km3 and 64-183 m, respectively. The maximum recorded ice thickness, ca. 619±13 m, is found in Austre Torellbreen. To estimate the ice volume of small non-echo-sounded tributary glaciers, we used a function providing the best fit to the ice thickness along the centre line of a collection of such tributaries where echo-soundings were available, and assuming parabolic cross-sections. We did some tests on the effect on the measured ice volumes of the distinct radio-wave velocity (RWV) of firn as compared to ice, and cold versus temperate ice, concluding that the changes in volume implied by such corrections were within the error bounds of our volume estimate using a constant RWV for the entire glacier inferred from common mid-point measurements on the upper ablation area
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