3,171 research outputs found

    Temporal video transcoding from H.264/AVC-to-SVC for digital TV broadcasting

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    Mobile digital TV environments demand flexible video compression like scalable video coding (SVC) because of varying bandwidths and devices. Since existing infrastructures highly rely on H.264/AVC video compression, network providers could adapt the current H.264/AVC encoded video to SVC. This adaptation needs to be done efficiently to reduce processing power and operational cost. This paper proposes two techniques to convert an H.264/AVC bitstream in Baseline (P-pictures based) and Main Profile (B-pictures based) without scalability to a scalable bitstream with temporal scalability as part of a framework for low-complexity video adaptation for digital TV broadcasting. Our approaches are based on accelerating the interprediction, focusing on reducing the coding complexity of mode decision and motion estimation tasks of the encoder stage by using information available after the H. 264/AVC decoding stage. The results show that when our techniques are applied, the complexity is reduced by 98 % while maintaining coding efficiency

    Corrections to 'temperature correction for cylindrical cavity perturbation measurements'

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    Protocol for the reconstruction of micromammals from fossils. Two case studies: The skulls of Beremendia fissidens and Dolinasorex glyphodon

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    We have developed a protocol for reconstructing 3D models of the skulls of extinct species of small mammals. For the first time, the reconstruction uses fragments of fossils from a mixture of different specimens and from related extant species. We use free software and commercial computers to make the process reproducible and usable for the scientific community. We present a semi-quantitative protocol to face the problem of making 3D reconstructions of fossil species that are incomplete in the fossil record and/or represented by a mixture of different individuals, as usually occurs with small vertebrates. Therefore this approach is useful when no complete skull is available. The protocol combines the use of microCT scan technology with a subsequent computer treatment using different software tools for 3D reconstruction from microCT and 3D design and printing (e.g. Fiji, SPIERS, Meshlab, Meshmixer) in a defined order. This kind of free and relatively simple software, plus the detailed description, makes this protocol practicable for researchers who do not necessarily have great deal of experience in working with 3D. As an example, we have performed virtual reconstructions of the skulls of two species of insectivore small mammals (Eulipotyphla): Beremendia fissidens and Dolinasorex glyphodon. The resulting skulls, plus models of the extant shrews Blarina brevicauda, Neomys fodiens, Crocidura russula and Sorex coronatus, make it possible to compare characteristics that can only be observed by means of microCT 3D reconstructions, and given the characteristics of the material, using this protocol. Among the characters we can compare are the position of the mandibles, the spatial relations among all the teeth, the shape of the snout and, in general, all parameters related with the anatomy of the rostrum. Moreover, these reconstructions can be used in different types of context: for anatomical purposes, especially to see internal features or characteristics at whole-skull scale, for bioengineering, animation, or other techniques that need a digital model

    Special issue on evapotranspiration measurement and modeling

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    Water availability for irrigation throughout the world has been reduced in recent years due to a combination of frequent droughts and competition for water resources among agricultural, industrial, and urban users. In addition, some major agricultural areas face moderate to significant reductions of rainfall, or changes in timing of stream flow due to changes in timing of snowmelt, as a result of global climate change. Under such conditions, sophisticated irrigation water management will be required to optimize water use efficiency and maintain sufficient levels of crop productivity and quality. A key factor to achieve these targets is the estimation of actual evapotranspiration (ET). Accurate determination of ET can be a viable tool in better utilization of water resources through well-designed irrigation management programs. Reliable estimates of ET are also vital to develop criteria for in-season irrigation management, water resource allocation, long-term estimates of water supply, demand and use, design and management of water resources infrastructure, and evaluation of the effect of land use and management changes on the water balance

    A cave occupied by cave bears for thousands of years in the Sobrarbe-Pirineos UNESCO Global Geopark (Huesca, Aragon, Spain)

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    The Sobrarbe-Pirineos UNESCO Global Geopark shows an extremely well-developed underground karst relief as a result of the great abundance and thickness of its limestone formations. The most important Pleistocene vertebrate site within the Geopark is Coro Tracito Cave at Tella. The fossil association is made up exclusively of bones belonging to Ursus spelaeus from the upper Pleistocene, accumulated over several thousand years. Based on scientific analysis of the fossil bones, an interesting public outreach project has been organized, involving the refurbishment of the site within the cave and the creation of a permanent exhibition called the Tella Cave Bear Museum. These two infrastructures are visited by thousands of tourists each year and constitute the main geoscientific tourist attraction of the Sobrarbe-Pirineos Geopark

    Special issue on evapotranspiration measurement and modeling

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    Water availability for irrigation throughout the world has been reduced in recent years due to a combination of frequent droughts and competition for water resources among agricultural, industrial, and urban users. In addition, some major agricultural areas face moderate to significant reductions of rainfall, or changes in timing of stream flow due to changes in timing of snowmelt, as a result of global climate change. Under such conditions, sophisticated irrigation water management will be required to optimize water use efficiency and maintain sufficient levels of crop productivity and quality. A key factor to achieve these targets is the estimation of actual evapotranspiration (ET). Accurate determination of ET can be a viable tool in better utilization of water resources through well-designed irrigation management programs. Reliable estimates of ET are also vital to develop criteria for in-season irrigation management, water resource allocation, long-term estimates of water supply, demand and use, design and management of water resources infrastructure, and evaluation of the effect of land use and management changes on the water balance

    Geographic mobility and social inequality among Peruvian university students

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    The purpose of this study was to explore geographic mobility among university students in Peru and to understand how mobility patterns differ by region and by demographic indicators of inequality. The ways that students may be able to move geographically in order to access quality higher education within the educational system can be a driver of equality or inequality, depending on who is able to take advantage. Using data from a university census, we examine how demographic indicators of inequality are related to geographic mobility for university attendance, how prior geographic mobility predicts later mobility for university attendance, and how these relationships differ based on the number and quality of universities in a region. Results show that sociodemographic variables related to social inequality explain a substantial amount of students\u27 postsecondary mobility. However, some of these relationships do not operate in the same way in all of the regions. Depending on the availability of universities and their quality, patterns of association between inequality and geographic mobility change. Implications for higher education policy as well as further research examining geographic mobility and inequality in education are discussed

    Museum libraries in Spain: A case study at state level

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    Special libraries are essential information and documentation centres for university teachers and researchers due to the quality and richness of their collections. In Spain, it is estimated that there are 2456 special libraries, although many are unknown either generally or among information professionals. These include museum libraries, which are important centres with valuable collections of bibliographic heritage for the area of Humanities and Social Sciences. The aim of this research is to gain an understanding of the real state of these information units and promote the social value of museum libraries in Spain. To do this, a survey was sent to the libraries of state-owned and -managed museums under the General Directorate of Fine Arts and Cultural Property (Ministry of Culture and Sports) of the Government of Spain. This general objective will be accompanied by a review of the scientific literature on various aspects of museum libraries at national and international level. After addressing the research methodology, the results obtained will be discussed and will include the following topics: collection management, library services and staff, economic and technological resources and finally, library management. Conclusions include recommendations for museum librarians and reveal that institutional cooperation is a strategic issue to improve both museum libraries visibility and their social recognition as cultural and research centre

    Birds from sima del elefante, atapuerca, spain: Palaeoecological implications in the oldest human bearing levels of the iberian peninsula

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    Palaeoenvironmental reconstruction of Early Pleistocene sites has a particular interest as it sheds light on how the arriving of the first Europeans occurred, as well as on the nature of the relation between these humans and the ecosystems. Bird remains are useful tools for this purpose, because they are commonly represented in the assemblages and most taxa still exist, allowing a direct comparison between past and extant birds associations. Here we analyse the bird remains from the Early Pleistocene levels of the Sima del Elefante site (1.1 to 1.5 million years old). Almost 10.000 remains belonging to at least 26 different taxa have been included. The assemblage is dominated by corvids and has a mixed origin, with cave-dwelling taxa dying in the cave and other taxa being accumulated by predators. The Sima del Elefante avian assemblage provides the oldest record of several taxa in the Iberian Peninsula (Haliaeetus albicilla, Corvus pliocaenus). Besides, here we report the oldest evidence of Imperial Eagle in the Iberian Peninsula, prior to the separation of the oriental and Iberian populations. The assemblage composition suggests that open environmental conditions were dominant, with minor presence of woodlands and water bodies, which is congruent with some previous approaches by other proxies. The first humans occupying the Iberian Peninsula inhabited under Mediterranean climate conditions, which gradually deteriorated, as reflected by the avian turnover recorded at the middle Pleistocene Atapuerca assemblages. © 2021 Universita degli Studi di Milano. All rights reserved

    Bone accumulation by leopards in the Late Pleistocene in the Moncayo Massif (Zaragoza, NE Spain)

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    Eating habits of Panthera pardus are well known. When there are caves in its territory, prey accumulates inside them. This helps to prevent its kill from being stolen by other predators like hyenas. Although the leopard is an accumulator of bones in caves, few studies have been conducted on existing lairs. There are, however, examples of fossil vertebrate sites whose main collecting agent is the leopard. During the Late Pleistocene, the leopard was a common carnivore in European faunal associations. Here we present a new locality of Quaternary mammals with a scarce human presence, the cave of Los Rincones (province of Zaragoza, Spain); we show the leopard to be the main accumulator of the bones in the cave, while there are no interactions between humans and leopards. For this purpose, a taphonomic analysis is performed on different bone-layers of the cave
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