A relaxation model for liquid-vapor phase change with metastability

We propose a model that describes phase transition including meta\-stable states present in the van der Waals Equation of State. From a convex optimization problem on the Helmoltz free energy of a mixture, we deduce a dynamical system that is able to depict the mass transfer between two phases, for which equilibrium states are either metastable states, stable states or {a coexistent state}. The dynamical system is then used as a relaxation source term in an isothermal 4$\times$4 two-phase model. We use a Finite Volume scheme that treats the convective part and the source term in a fractional step way. Numerical results illustrate the ability of the model to capture phase transition and metastable states

Trying the Trial

Lawyers routinely make strategic advocacy choices that reflect directly, if inferentially, on the credibility of their clients’ claims and defenses. But courts have historically been reluctant to admit evidence of litigation conduct, sometimes even expressing hostility at the very notion of doing so. This Article deconstructs that reluctance. It argues not only that litigation conduct has probative value, but also that there is social utility in subjecting lawyer behavior to juror scrutiny

Virtual sector profiles for innovation sharing in process industry : sector 01: chemicals

Production data in process industry are proprietary to a company since they are key to the process design and technology expertise. However, data confidentiality restrains industry from sharing results and advancing developments in and across process sectors. Using virtual profiles that simulate the typical operating modes of a given process industry offers an elegant solution for a company to share information with the outside world. This paper proposes a generic methodology to create sector blueprints and applies it to the chemicals industry. It details the profile of a typical chemical site based on essential units and realistic data gathered from existing refineries and chemical plants

Ulvan Lyases Isolated from the Flavobacteria Persicivirga ulvanivorans Are the First Members of a New Polysaccharide Lyase Family

International audienc

Vertical project : designing fruit agroforestry systems for a renewed horticulture

Although it's addressing multiple issues for modern farming, agroforestry mixing fruit trees and annual crops (mainly vegetables) has not been so well documented under temperate climate. One expected amenity of agroforestry is to increase biodiversity and natural pest regulation within the plot. While fruit trees are among the crops that rely most on plant protection products, we made the hypothesis that introduction of annual crops in the perennial system can lead to effective biocontrol and to input reduction, while developing other synergies between crops (shadow beneficial effects, water limitation, ….) or social amenities. On two locations (Durette/TAB) in southern France, with different characteristics (crop rotation, marketing, surface...), the partners of a 6-years funded project called Vertical, designed in 2012 and 2013 innovative cropping systems addressing those specific constraints, in order to optimize their global performance. These systems have been implemented in 2013 and 2014. Sustainability indicators have been discussed and selected to (i) monitor and (ii) to assess these systems. An ex ante assessment tool has been developed under a participatory approach, to stimulate the co-design of new performant plots. This tool will shortly be adapted to ex-post assessment, so that advisors but also farmers dealing with fruit agroforestry systems can identify their main bottlenecks and assets. A link to the national bottom-up network of fruit agroforestry systems (called Smart) will be achieved this way

L'enherbement permanent comme alternative au travail mécanique sous les oliviers

Le travail mécanique au pied de l'arbre, pour contrôler l'enherbement, demande trop d'attention et d'énergie pour un résultat souvent imparfait. Les agriculteurs sont demandeurs d'alternatives fiables aux herbicides et au travail mécanique. Une flore adaptée au pied des arbres représente une solution séduisante d'autant plus qu'elle peut jouer un rôle agroécologique utile. L'expérimentation a permis de suivre le développement d'espèces couvre-sols, choisies en fonction de résultats obtenus sur d'autres vergers, et de leurs propriétés attendues (faible concurrence, port ras, étalement rapide). Certaines espèces ont des comportements adaptés aux conditions de culture de l'olivier

Vertical project : designing fruit agroforestry systems for a renewed horticulture

Although it's addressing multiple issues for modern farming, agroforestry mixing fruit trees and annual crops (mainly vegetables) has not been so well documented under temperate climate. One expected amenity of agroforestry is to increase biodiversity and natural pest regulation within the plot. While fruit trees are among the crops that rely most on plant protection products, we made the hypothesis that introduction of annual crops in the perennial system can lead to effective biocontrol and to input reduction, while developing other synergies between crops (shadow beneficial effects, water limitation, ….) or social amenities. On two locations (Durette/TAB) in southern France, with different characteristics (crop rotation, marketing, surface...), the partners of a 6-years funded project called Vertical, designed in 2012 and 2013 innovative cropping systems addressing those specific constraints, in order to optimize their global performance. These systems have been implemented in 2013 and 2014. Sustainability indicators have been discussed and selected to (i) monitor and (ii) to assess these systems. An ex ante assessment tool has been developed under a participatory approach, to stimulate the co-design of new performant plots. This tool will shortly be adapted to ex-post assessment, so that advisors but also farmers dealing with fruit agroforestry systems can identify their main bottlenecks and assets. A link to the national bottom-up network of fruit agroforestry systems (called Smart) will be achieved this way

Effets des polluants sur les écosystèmes récifaux

During the last decade, it has proven more and more obvious that coral reefs have become the most threatened class of ecosystems of the world far before the tropical forests. Indeed, not only their global area is much lower but the coral reefs are affected by the largest array of degradation factors, especially toxic pollutants, strictly related to human impacts on the oceanic and global environment. A significant part of reef pollution results from the discharge into marine environment of a large range of pollutants: hazardous chemicals, oil offshore industry and piping of crude oil, lastly from atmospheric transfer of chemicals to the surface of the sea via precipitations. Subsequently will be found in reef waters and sediments a number of toxic metals, hydrocarbon, persistent organic pollutants (POPs), pesticides discharged from land by run off, especially herbicides, as well as antifouling paintings not to mention cyanides widely in unlawful use for reef fishing in developing countries. POPs have been detected in reef ecosystems everywhere they have been investigated. Even non-persistent pesticides are currently found in reef waters and sediments located next from coastal intensive tropical crops. Studies on ecotoxicological effects of reef pollutions have been carried out at various extents according to the class of chemical concerned. Though oil impact on reefs and even heavy metals pollution has been rather intensively investigated, at the opposite, pesticides and especially herbicides have given way to a much smaller number of researches. This fact is quite surprising as herbicides display an impressive potential impact on hermatypic scleractinians due to their extreme toxicity for Dinoflagellate symbiotic algae. Various studies have shown up that a number of toxic pollutants such as hydrocarbons, pesticides or cyanides prevent coral gametes fecundation and the settlement of planula as well as their further metamorphosis, impeding therefore the colonies renewal or the restoration of the ones already degraded subsequently to human activities. Other investigations demonstrated that reef bleaching could be generated by exposure to very low levels of herbicides as well as cyanides that trigger the loss of zooxanthellae. On the other hand, lower concentrations of herbicides, sometime in the order of one μg.L–1 as diuron and various triazines, can inhibit photosynthesis. Additionally to their direct effects on hermatypic scleractinians, toxic pollutants discharged into the coral reefs environment can impinge on other reef habitats of the coral ecosystem, especially on the sea-grass beds growing in its lagoons. Lastly, the impact of various terrigenic pollutants, as herbicides, on other coastal ecosystems especially mangrove can indirectly act on coral reef communities with which they share some of their components, especially fishes and invertebrates: a number of reef species relying on mangrove habitat as nurseries for their larval and/or their juvenile instarsIl est devenu de plus en plus évident au cours de la dernière décennie que les récifs coralliens représentent de loin le type d'écosystème le plus menacé de la planète, beaucoup plus que les forêts tropicales. En effet non seulement leur surface totale est beaucoup plus faible, mais à la différence de ces dernières, ils sont exposés à tous les types de dégradations d'origine anthropique en particulier au spectre complet des polluants toxiques. Une fraction significative des polluants des récifs proviennent de rejets en mer d'une large gamme de composés chimiques dangereux, de l'exploitation de gisements de pétrole offshore, et enfin du transfert de polluants atmosphériques dans les eaux marines via les précipitations. En conséquence, des métaux toxiques, des hydrocarbures, des polluants organiques persistants, des pesticides d'origine tellurique, en particulier des herbicides, vont se retrouver dans les eaux récifales ainsi que des peintures antifouling, enfin, on citera les cyanures utilisés dans la pêche récifale. Les polluants organiques persistants ont été mis en évidence dans les écosystèmes de toutes les grandes provinces récifales du monde. Même les pesticides non persistants peuvent être détectés dans tous les récifs du globe jouxtant des cultures littorales. Les conséquences écotoxicologiques des pollutions récifales ont été étudiées de façon diverse selon les contaminants concernés. Si les effets du pétrole ont donné lieu à un nombre significatif de publications, il n'en est pas de même des pesticides en particulier des herbicides, lesquels constituent pourtant des polluants particulièrement redoutables pour les récifs coralliens en raison de leur forte toxicité potentielle pour les algues symbiotiques des scléractiniaires hermatypiques. Certains travaux ont montré que divers polluants toxiques tels les hydrocarbures, les pesticides ou les cyanures perturbent la fécondation et la fixation des larves planula des polypes, entravant, de ce fait, le renouvellement des colonies et la restauration des récifs déjà dégradés par l'homme. D'autres recherches ont révélé que les herbicides mais aussi les cyanures pouvaient provoquer le blanchissement des coraux en induisant l'expulsion des zooxanthelles par les polypes. En outre, à de plus faibles concentrations, parfois de l'ordre du μg.L-1, des herbicides comme le diuron ou certaines triazines sont susceptibles d'inhiber la photosynthèse de ces algues symbiotiques. En plus de leurs actions directes sur les sléractiniaires hermatypiques, les polluants toxiques rejetés dans les eaux récifales peuvent aussi agir sur d'autres habitats propres aux écosystèmes coralliens, en particulier sur les herbiers de phanérogames marines propres au lagon. Enfin, l'action des polluants d'origine tellurique sur d'autres écosystèmes, qui jouxtent les récifs, en particulier sur les mangroves, peut avoir des conséquences désastreuses pour les biocoenoses coralliennes avec lesquels ils échangent une fraction de certains de leurs peuplements. En effet, les eaux des mangroves jouent le rôle de nurseries pour les stades larvaires et pour les juvéniles de nombreuses espèces de poissons et d'invertébrés récifaux de telle sorte que la dégradation de ces dernières implique des conséquences néfastes pour les communautés récifales

Effect of forest management on plant species diversity in Castanea sativa stands in Salamanca (Spain) and the Cévennes (France).

For the last centuries, marked land use changes have taken place throughout the Mediterranean region. These changes have a great impact on plant diversity, variations of which can affect in return ecosystem functioning. This is particularly true for sweet chestnut (Castanea sativa Mill.) stands (groves or coppices) that have been more or less abandoned since the end of the last century. Thus, our objective was to analyse the consequences of various management types on plant species diversity, or to analyse if the land use changes may affect the diversity of plant species in chestnut areas of Southern Europe: in chestnut stands of the Honfría forest, located in the South of Salamanca province in Spain, and in the Cévennes in Southern France. Results indicate that plant species diversity is higher in groves than in coppice stands. Cultivated groves were generally characterized by small heliophilous therophytes, and abandoned groves by hemicryptophytes with anemochorous dispersal mode and chamaephytes. Coppice stands were characterized more particularly by phanerophytes with zoochorous dispersal mode. Thus, plant species diversity differs according to management types. The 17% of common species were found between the two Mediterranean areas studied. This difference can be explained by different ecological conditions (elevation, soil type), different management types (grove, coppice stand), and different stand characteristics (shoot density, diameter at breast height). The cultivated grove plots were very different from the other stands that constituted one sub-group. In the Honfría forest, the values of Jaccard index indicated that the cultivated grove had a plant species composition very different from the other stands. In the Cévennes, the lowest values of the Jaccard index were also found between the cultivated grove and the other stands. One solution could be to maintain a landscape mosaic constituted of diverse chestnut stands modified by human activities (chestnut groves, abandoned chestnut groves and chestnut coppice stands). This could allow the enhancement of the high regional plant diversity.We thank the European Union (MANCHEST QLK5-CT- 2001 – 00029 z contracts, DG XII, for financial support).Peer reviewe

Mise en évidence et validation de biomarqueurs écotoxicologiques dans la population d'anguilles d'un étang de la réserve naturelle nationale de Camargue, le Vaccarès, exposée à des polluants organiques persistants

Bien que située dans une zone assez isolée du delta du Rhône et de ce fait exempte de toute activité industrielle, la Réserve Naturelle Nationale de Camargue n'en est pas moins exposée à une contamination diffuse par divers polluants organiques persistants, parmi lesquels des hydrocarbures aromatiques polycycliques (HAP) et des composés organochlorés (OC). En raison des particularités de cette contamination, la recherche de biomarqueurs chez les anguilles du Vaccarès se sont orientées vers une analyse multi-paramétrique qui s'intéresse à des réponses métaboliques incluant non seulement les mécanismes de détoxication (biotransformation, antioxydant) et les besoins énergétiques, mais aussi d'autres processus métaboliques « aspécifiques ». Il s'agit de marqueurs enzymatiques membranaires dont certains ont un rôle dans la conduction neuronale (acétylcholinestérase, AChE), dans l'osmorégulation, et/ou dans le métabolisme énergétique (ATPases). A l'issue de ces travaux le taux de glycogène tissulaire s'avère être un marqueur sensible ainsi que trois activités enzymatiques hépatiques impliquées dans la défense contre les espèces réactives de l'oxygène: catalase, glutathion peroxydase (SeGPx) et superoxyde dismutases, (SOD). Par ailleurs les ATPases musculaires et branchiales et l'AChE musculaire et cérébrale présentent une plus grande significativité, en termes de biomarqueurs, que les enzymes de biotransformation éthoxyrésorufine-O-dééthylase (EROD) et uridine diphospho-glucuronyl transférase (UDPGT). Cependant la plupart de ces activités enzymatiques sont dépendantes d'un certain nombre de facteurs abiotiques. Cette étude apporte des éléments de discussion quant à la validation, dans les populations et les peuplements naturels, des données écotoxicologiques obtenues au laboratoire. Elle soulève également la question de la localisation tissulaire de l'imprégnation exprimant l'ancienneté ou le mode de contamination et de son influence sur la réponse des biomarqueurs. Enfin, si la validation des biomarqueurs membranaires se confirme, cette étude, par son approche novatrice, dresse un premier bilan de la menace écotoxicologique qui pèse sur les organismes aquatiques d'une aire protégée, résultant en particulier de l'incorporation de polluants organiques persistants (POP) dans les membranes cellulaires.Though located in a rather remote area free from neighbouring industrial activities, the French National Nature Reserve of Camargue is however exposed to a non point source contamination by a number of persistant organic pollutants, particularly polycyclic aromatic hydrocarbons (PAH) and organochlorine compounds (OC). Due to the nature of this contamination, investigations about validation of biomarkers in the eels of the Vaccarès lagoon have proven to be of the utmost importance. They have been focused on the characterization and validation of biomarkers related to metabolic responses including, not only the detoxification mechanisms (biotransformation, antioxidant process) and the energy requirements, but also some unspecific metabolic processes. These last ones are enzymatic membrane markers implicated either in the neuronal conduction (acetylcholinesterase, AChE) or in the osmoregulation and the energy metabolism (ATPases). The experimental results have been screened by the way of a multivariate analysis. It may be concluded that the rate of tissue glycogen seems to be a sensitive biomarker as well as three hepatic activities involved in the protection against oxyradicals : catalase, glutathion peroxidase (SeGPx) and superoxide dismutases (SOD). The muscle and gill ATPases as well as the muscle and brain AChE show more significant results in term of biomarkers than the biotransformation enzymes : ethoxyresorufine-O-deethylase (EROD) and uridine diphospho-glucuronyl transferase (UDPGT). However most of these enzymatic activities depend on a number of abiotic factors. This study brings some conclusive elements for the validation of the biomarkers use from data obtained in laboratory studies to their application in field ecotoxicology. It also raises the question about the tissue location of the contaminant in fish, in relationship to their age or their mode of contamination, and its influence on the biomarkers response. As a conclusion, if the validation of membrane indicators is confirmed, this study, by its innovative approach, provides the first statement on the extent of the ecotoxicological threat for the aquatic species in a protected area, stemming from the occurrence of persistent organic pollutants (POP) in the cell membranes