Axisymmetric Solutions to Einstein Field Equations via Integral Transforms

In this paper, we present new axisymmetric and reflection symmetric vacuum solutions to the Einstein field equations. They are obtained using the Hankel integral transform method and all three solutions exhibit naked singularities. Our results further reinforce the importance and special character of axisymmetric solutions in general relativity and highlight the role of integral transforms methods in solving complex problems in this field. We compare our results to already existing solutions which exhibit the same type of singularities. In this context we notice that most known axial-symmetric solutions possess naked singularities. A discussion of characteristic features of the newly found metrics, e.g., blueshift and the geometry of the singularities, is given.Comment: 20 pages, 6 figure

Le coton biologique au Paraguay. 1. Construction de la filière et contraintes économiques

Organic cotton production in Paraguay. 1. Some economic limitations for a novel industry. Paraguay, whose small farmers are traditionally cotton growers, has begun to crop and process organic cotton since 2003. An exploratory study was carried out in order to have a better knowledge of the way the organic cotton production has developed and to detect eventual economic limitations. The study was achieved in 2008 during the cotton harvest period by interviewing the actors from the farm to the industrial level. The organic cotton industry was built by a single company in a favorable national (20 years of organic production for a diversity of crops) and international (an increasing demand for organic products, including cotton) context. This single company applied a strategy of creating alliances with NGOs, public authorities and other private operators, in order to increase farm production – by adding new farmers – and textile manufacture and trade worldwide. We detected three kinds of economic limitations. Firstly, organic cotton production still remained largely dependent on the conventional cotton industry for the supply of seed. Secondly, the cumbersome certification process at farm level and its cost associated with increased logistic problems derived from the increase in geographical dispersion of small producers appeared to seriously limit the possibilities for expansion. Thirdly, although the price paid for organic cotton was 12-14% higher in 2008, the obligation for the farmers to sell drier cotton and a longer buying process resulting in delayed cash payments led many farmers to sale a large part of their organic cotton to conventional buyers. We recommend in-depth studies on these three topics to acquire a better knowledge of their extent in terms of intensities and variations, and to propose measures to mitigate them

Claude Debru – « Penser avec les mains » : critique génétique et épistémologie

Ce numéro de Genesis aurait été incomplet sans une réflexion sur les archives scientifiques et l’apport de la critique génétique dans l’exploitation de celles-ci. Claude Debru, directeur du département de philosophie de l’École normale supérieure, membre correspondant de l’Académie des sciences, spécialiste de l’histoire des sciences du vivant, a bien voulu répondre à nos questions. Jean-Louis Lebrave – Dans le numéro de Genesis consacré à l’écriture scientifique, Anouk Barberousse et Laurent..

Le pari éthique de la complexité (Action médicale dans le champ des accidents vasculaires cérébraux graves)

L accident vasculaire cérébral, est une pathologie aigüe et grave, qui peut conduire au décès rapide du patient ou à un handicap neurologique sévère, moteur et/ou cognitif. Dans les situations les plus sévères, l action médicale amène à envisager des limitations ou arrêt de certains traitements si le pronostic s avère catastrophique , signifiant le plus souvent le risque d un handicap inacceptable .L action médicale dans ces situations est particulièrement complexe. Elle pose la question de la finalité de l acte médical au regard de la qualité de vie future du patient, qui suppose l estimation délicate de la valeur de la vie, prédiction par essence incertaine. Mais si le pronostic tient une place centrale dans cette action, d autres facteurs jouent également un rôle déterminant, comme celui du contexte. Ce travail de thèse propose une exploration des notions de pronostic et de proportionnalité des soins et une approche éthique reposant sur la prise en compte de la complexité et la délibération aristotélicienne.Stroke is an acute and severe pathology, which can lead to rapid death or severe neurological motor and / or cognitive disability. In the most severe situations, medical action leads to consider withholding or withdrawal of treatments, if the prognosis appears to be "catastrophic", meaning most often the risk of "unacceptable" disability.The medical action in these situations is particularly complex. It raises the question of the purpose of the medical act in relation to the future quality of life of the patient, which involves the delicate estimate of the value of life, prediction inherently uncertain. But if the prognosis holds a central place in this action, other factors also play a role, such as the context. This thesis offers an exploration of the concepts of prognosis and proportionality care and an ethical approach based on taking into account the complexity and Aristotelian deliberation.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Balearic shearwater and northern gannet bycatch risk assessment in Portuguese Continental Waters

Even though incidental captures in fisheries are one of the major threats to seabirds, bycatch has been difficult to quantify and specific risk areas are rarely identified. The present study evaluates the potential fisheries bycatch effect on two of the most emblematic seabird species wintering off continental Portugal, the critically endangered Balearic Shearwater and Northern Gannet. Information was collected by on-board observers and voluntary logbooks kept by fishing boat captains. Each species' Potential Biological Removal (for the study area) was based on the respective population abundance estimated through aerial surveys. The analysis of bycatch mortality identified the Fixed Gear in the Polyvalent fleet and Purse Seiners as the fisheries with the highest Balearic Shearwater bycatch rate. Longline and Fixed Gear fisheries had the highest Northern Gannet bycatch rate. The Potential Biological Removal thresholds were 41 Balearic Shearwaters per year (CI ¼ 20–83) and 2345 Northern Gannets per year (CI ¼ 2049–2680). The overlap between the predictive species distribution maps and fisheries density maps allowed for a seabird Bycatch Risk Assessment. The higher Balearic Shearwater bycatch risk was obtained for Fixed Gear and Purse Seines and the highest Northern Gannet bycatch risk was obtained for Longline and Fixed Gear fisheries. Bycatch mitigation measures should be applied in fisheries presenting the higher bycatch risks. This study identifies the potential areas where Balearic Shearwater and Northern Gannet bycatch is more likely to occur, including some of the already designated Special Protection Areas where management and conservation measures should urgently be applied.info:eu-repo/semantics/publishedVersio