63 research outputs found

    Проблеми інноваційного розвитку підприємств вугільної галузі України

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    Метою статті є визначення проблем інноваційного розвитку вугільної галузі та напрями його забезпечення шляхом упровадження інновацій

    Diagrammes de puissance restreint sur le GPU

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    International audienceWe propose a method to simultaneously decompose a 3D object into power diagram cells and to integrate given functions in each of the obtained simple regions. We offer a novel, highly parallel algorithm that lends itself to an efficient GPU implementation. It is optimized for algorithms that need to compute many decompositions, for instance, centroidal Voronoi tesselation algorithms and incompressible fluid dynamics simulations. We propose an efficient solution that directly evaluates the integrals over every cell without computing the power diagram explicitly and without intersecting it with a tetrahedralization of the domain. Most computations are performed on the fly, without storing the power diagram. We manipulate a triangulation of the boundary of the domain (instead of tetrahedralizing the domain) to speed up the process. Moreover, the cells are treated independently one from another, making it possible to trivially scale up on a parallel architecture. Despite recent Voronoi diagram generation methods optimized for the GPU, computing integrals over restricted power diagrams still poses significant challenges; the restriction to a complex simulation domain is difficult and likely to be slow. It is not trivial to determine when a cell of a power diagram is completely computed, and the resulting integrals (e.g. the weighted Laplacian operator matrix) do not fit into fast (shared) GPU memory. We address all these issues and boost the performance of the state-of-the-art algorithms by a factor 2 to 3 for (unrestricted) Voronoi diagrams and a ×50 speed-up with respect to CPU implementations for restricted power diagrams. An essential ingredient to achieve this is our new scheduling strategy that allows us to treat each Voronoi/power diagram cell with optimal settings and to benefit from the fast memory

    Impact of environmental and genetic factors on the scale shape of zebrafish, Danio rerio (Hamilton 1822): A geometric morphometric study

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    Intraspecific morphological variability may reflect either genetic divergence among groups of individuals or response of individuals to environmental circumstances within the frame of phenotypic plasticity. Several studies were able to discriminate wild fish populations based on their scale shape. Here we examine whether the variations in the scale shape in fish populations could be related to genetic or environmental factors, or to both of them. In the first experiment, two inbred lines of zebrafish Danio rerio (Hamilton 1822) reared under identical environmental conditions were compared. Secondly, to find out what effect environmental factors might have, offsprings were divided into two groups and reared on different diets for 12 weeks. Potential recovery of scales from an environmental effect was also assessed. Experimental groups could successfully be distinguished according to the shape of scales in both experiments, and the results showed that both genetic and environmental factors may notably influence scale shape. It was concluded that scale shape analysis might be used as an explanatory tool to detect potential variability of environmental influences impacting genetically homogeneous groups of fish. However, due to its sensitivity to environmental heterogeneity, the applicability of this technique in identifying intraspecific stock membership of fish could be limited

    The great melting pot. Common sole population connectivity assessed by otolith and water fingerprints

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    Quantifying the scale and importance of individual dispersion between populations and life stages is a key challenge in marine ecology. The common sole (Solea solea), an important commercial flatfish in the North Sea, Atlantic Ocean and the Mediterranean Sea, has a marine pelagic larval stage, a benthic juvenile stage in coastal nurseries (lagoons, estuaries or shallow marine areas) and a benthic adult stage in deeper marine waters on the continental shelf. To date, the ecological connectivity among these life stages has been little assessed in the Mediterranean. Here, such an assessment is provided for the first time for the Gulf of Lions, NW Mediterranean, based on a dataset on otolith microchemistry and stable isotopic composition as indicators of the water masses inhabited by individual fish. Specifically, otolith Ba/Ca and Sr/Ca profiles, and delta C-13 and delta O-18 values of adults collected in four areas of the Gulf of Lions were compared with those of young-of-the-year collected in different coastal nurseries. Results showed that a high proportion of adults (>46%) were influenced by river inputs during their larval stage. Furthermore Sr/Ca ratios and the otolith length at one year of age revealed that most adults (similar to 70%) spent their juvenile stage in nurseries with high salinity, whereas the remainder used brackish environments. In total, data were consistent with the use of six nursery types, three with high salinity (marine areas and two types of highly saline lagoons) and three brackish (coastal areas near river mouths, and two types of brackish environments), all of which contributed to the replenishment of adult populations. These finding implicated panmixia in sole population in the Gulf of Lions and claimed for a habitat integrated management of fisherie

    Are we ready to track climate-driven shifts in marine species across international boundaries? - A global survey of scientific bottom trawl data

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    Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of data availability, and mismatch between data and real species distributions. To assess the extent of this challenge, we review the global status and accessibility of ongoing scientific bottom trawl surveys. In total, we gathered metadata for 283,925 samples from 95 surveys conducted regularly from 2001 to 2019. We identified that 59% of the metadata collected are not publicly available, highlighting that the availability of data is the most important challenge to assess species redistributions under global climate change. Given that the primary purpose of surveys is to provide independent data to inform stock assessment of commercially important populations, we further highlight that single surveys do not cover the full range of the main commercial demersal fish species. An average of 18 surveys is needed to cover at least 50% of species ranges, demonstrating the importance of combining multiple surveys to evaluate species range shifts. We assess the potential for combining surveys to track transboundary species redistributions and show that differences in sampling schemes and inconsistency in sampling can be overcome with spatio-temporal modeling to follow species density redistributions. In light of our global assessment, we establish a framework for improving the management and conservation of transboundary and migrating marine demersal species. We provide directions to improve data availability and encourage countries to share survey data, to assess species vulnerabilities, and to support management adaptation in a time of climate-driven ocean changes.En prensa6,86

    Intégration d'un processeur cellulaire pour une architecture pyramidale de traitement d'image

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    This paper presents the integration of a cellular multiprocessor pyramidal computer architecture. The interest of such organization, especially for picture processing, is discussed ; then the design of a prototype LSI and its expected performances are detailed.Cet article traite de l'intégration d'une architecture pyramidale de multi-processeur cellulaire. Il explique l'intérêt de ce type d'organisation notamment pour le traitement des images, puis présente la manière dont a été implanté un circuit intégré expérimental ainsi que les performances attendues

    Fish community structure of two Greek close gulfs (Lesvos Island, Aegean Sea)

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    Minimal Geodesics Along Volume-Preserving Maps, Through Semidiscrete Optimal Transport

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    Distribution and activity of Bacteria and Archaea in the different water masses of the Tyrrhenian Sea

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    This study examines the abundance of the Bacteria, Crenarchaeota and Euryarchaeota and bulk activities (phosphatase and aminopeptidase activities, heterotrophic prokaryotic production and dark CO2 fixation) in the major water masses of the Tyrrhenian Sea (from surface to bottom: Modified Atlantic Water (MAW); Levantine Intermediate Water (LIW) and Tyrrhenian Deep Water (TDW)) in July and December 2005. Data from the catalyzed reporter deposition coupled with fluorescence in situ hybridization (CARD-FISH) analyses indicate that the percentage of Bacteria was always higher than the percentage of Crenarchaeota and Euryarchaeota throughout the water column. While the percentage of Euryarchaeota was relatively homogeneous ( 10%) through the water column, the percentage of Crenarchaeota increased with depth (from 5% to 14% in July and from 7% to 17% in December in MAW and TDW, respectively). Regarding differences between July and December 2005, the percentage of Bacteria in the MAW was lower in July than in December (25% versus 43%, respectively) while quite constant ( 40%) in the TDW. The pattern of phosphatase and aminopeptidase activity varied according to the stations considered, but both ectoenzyme activities showed higher maximum velocity rates in July than in December in the deep-sea waters. Particularly, specific activity of phosphatase in the deepsea waters (TDW) was 7 times higher (median value) than in surface waters (MAW). Prokaryotic production, aminopeptidase and phosphatase activity measurements were always higher under in situ pressure conditions than after decompression. For the first time, the measurement of the dark CO2 fixation was investigated under in situ pressure conditions and its decompressed counterparts. These data give new information to understanding the role of prokaryotes (Bacteria and Archaea) in biogeochemical cycles of the meso- and batypelagic waters of the oceans

    Spatio-temporal dynamics of exploited groundfish species assemblages faced to environmental and fishing forcings : insights from the mauritanian exclusive economic zone

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    Environmental changes and human activities can have strong impacts on biodiversity and ecosystem functioning. This study investigates how, from a quantitative point of view, simultaneously both environmental and anthropogenic factors affect species composition and abundance of exploited groundfish assemblages (i.e. target and non-target species) at large spatio-temporal scales. We aim to investigate (1) the spatial and annual stability of groundfish assemblages, (2) relationships between these assemblages and structuring factors in order to better explain the dynamic of the assemblages' structure. The Mauritanian Exclusive Economic Zone (MEEZ) is of particular interest as it embeds a productive ecosystem due to upwelling, producing abundant and diverse resources which constitute an attractive socio-economic development. We applied the multi-variate and multi-table STATICO method on a data set consisting of 854 hauls collected during 14-years (1997-2010) from scientific trawl surveys (species abundance), logbooks of industrial fishery (fishing effort), sea surface temperature and chlorophyll a concentration as environmental variables. Our results showed that abiotic factors drove four main persistent fish assemblages. Overall, chlorophyll a concentration and sea surface temperature mainly influenced the structure of assemblages of coastal soft bottoms and those of the offshore near rocky bottoms where upwellings held. While highest levels of fishing effort were located in the northern permanent upwelling zone, effects of this variable on species composition and abundances of assemblages were relatively low, even if not negligible in some years and areas. The temporal trajectories between environmental and fishing conditions and assemblages did not match for all the entire time series analyzed in the MEEZ, but interestingly for some specific years and areas. The quantitative approach used in this work may provide to stakeholders, scientists and fishers a useful assessment for the spatio-temporal dynamics of exploited assemblages under stable or changing conditions in fishing and environment
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