Nordic Electricity Congestion's Arrangement as a Model for Europe: Physical Constraints or Operators' Opportunity

Nordic Electricity Congestion's Arrangement as a Model for Europe: Physical Constraints or Operators' Opportunit

Governance of substance use as a by-product of policing in Norway : a historical account

A

Nordic electricity congestion's arrangement as a model for Europe : physical constraints or operators' opportunism?

Congestion on power grids seems a physical reality, a "hard" fact easy to check. Our paper models a different idea: congestion signal may be distorted by transmission system operators (TSOs), which puts the European integrated electricity market at risk. 1ʻ when the TSOs share the revenue produced by congestion's pricing they have an incentive in distorting data. 2ʻ because congestion signals are not physical data but "home made" conventions, TSOs could be able distorting them. 3ʻ when congestion appears on cross border lines that link several countries with their own regulatory mechanisms, the settlement of this incentive's problem necessitates a high degree of coordination. Congestion puts undoubtedly the threat of a collapse on interconnected grids. The "capacity constrained situations" have therefore to be avoided. Congestion signalling depends on norms set by TSOs and a signal is given when the power flows attain the "secure" limits set by TSOs. These security norms are not stable and invariable because some flexibility is needed by the very nature of the power flows and because lines physical capacity limits are not constant. Therefore TSOs are defining the congestion signal on a variable, complex and non transparent constraint and may manipulate it for their own interests. In Nordic countries the "Light Handed Regulation" makes this opportunistic behaviour more likely. We need a more effective congestion regulatory mechanism.Supported by the MIT Center for Energy and Environmental Policy Research

Simulations expérimentale et numérique de réfractaires verriers électrofondus riches en zircone

International audienceLes réfractaires électrofondus à Très Haute Teneur en Zircone sont utilisés dans la construction des fours verriers. Le fond de la zone fusion est constitué de dalles de THTZ (88%vol ZrO2, 12%vol phase vitreuse), matériau choisi pour sa faible conductivité thermique, sa forte réfractarité et son inertie chimique. Le THTZ est élaboré par électrofusion, coulé dans des moules puis refroidi de manière contrôlée jusqu'à température ambiante, domaine où le matériau se caractérise par un comportement fragile. Lors de la première mise en chauffe du four ("attrempage"), des contraintes internes d'origine thermique sont générées au sein des dalles. L'objectif de l'étude est alors d'estimer ce champ de contraintes. L'étude a tout d'abord consisté à simuler expérimentalement la chauffe d'une dalle de THTZ dans un four verrier pendant l'attrempage. Pour ce faire, nous avons développé et utilisé un dispositif expérimental consistant à poser une dalle de THTZ instrumentée en thermocouples sur une plaque chauffée à une vitesse contrôlée. Les données thermiques ainsi obtenues ont permis, via un calcul numérique thermique (code de calcul ZéBuLoN, Centre des Matériaux), de déterminer les coefficients d'échange aux interfaces dalle/air et dalle/plaque chauffante. Puis, à partir de cela, un calcul numérique mécanique nous a permis de déterminer les contraintes générées par l'attrempage dans la dalle

Transgenesis and humanization of murine antibodies.

International audienceThe properties of monoclonal antibodies explain why they are such a successful class of therapeutic molecules. However, pionneered initial antibodies were of murine origin and triggered an immune response which limited the therapeutic potential of the antibody and generated deleterious effects. Consequently, tremendous efforts have been developped to engineer these murine Ig by introducing human sequences in vitro, or in vivo by humanization of murine antibodies, leading to chimeric immunoglobulins, and more recently generation of fully human antibodies in transgenic mice with a more or less diversified V repertoire. These approaches have led to the development of an increasing number of these chimeric or humanized monoclonal antibodies entering pharmaceutical pipelines. double dagger

Arcing on Solar Generators by Collection of Ionospheric Plasma Currents

International audienceThere are several well-known possibilities to trigger a secondary arc on solar arrays by creation of conductive plasma produced in the gap between two solar cell strings. It could be by electrostatic discharges due to an inverse potential gradient condition, micrometeoroid impacts or laser impacts. The development of electrical propulsion for satellites requires higher voltages on solar arrays. These voltages strongly modify the plasma-satellite interactions, especially by increasing the collection of plasma currents. By studying this plasma collection current on solar cell samples, we have detected secondary arcs between two strings without any triggering event as previously described. Focusing on this event, we found that a series of physical phenomena may lead to secondary arcing situation: heating by plasma current collection, outgassing, Paschen discharge conditions and then secondary arcing. We have reproduced on solar cell like samples what occurs when an arc starts and the conditions for its occurrence. Thereby, we have defined when this phenomenon is able to happen on real solar arrays

Selection on the wing in Heliconius butterflies

<p>Asbtract</p> <p>To what extent population structure favours the establishment of new phenotypes within a species remains a fundamental question in evolutionary studies. By reducing gene flow, habitat fragmentation is a major factor shaping the genetic structuring of populations, favouring isolation of small populations in which drift may rapidly change frequencies of new variants. When these variants provide advantages to individuals, the combined effect of selection and drift can lead to rapid shifts in phenotypes. In a study published in <it>BMC Genetics</it>, Albuquerque de Moura <it>et al. </it>asked whether such a general pattern of population structure can be observed in <it>Heliconius </it>species, which could have strong implication in the evolution of colour pattern diversification in these butterflies. In this commentary we discuss the potential roles of these three processes (drift, selection and dispersal) on the evolution of <it>Heliconius </it>wing patterns in regard to the findings of a common fine-scale population structure within the co-mimetic species <it>H. melpomene </it>and <it>H. erato</it>. Indeed, a general pattern of population subdivision in the history of these two species may have provoked the major phenotypical shifts observed in their wing colour patterns. The suggestion that coupled environmental pressures (counter-selection of dispersal and selection on co-evolved traits) could be responsible for identical genetic differentiation profiles in <it>H. erato </it>and <it>H. melpomene </it>clearly merits further investigations using both detailed population genetic (including landscape genetic) and ecological studies.</p

Welfare of broilers on farm

This Scientific Opinion considers the welfare of domestic fowl (Gallus gallus) related to the production of meat (broilers) and includes the keeping of day-old chicks, broiler breeders, and broiler chickens. Currently used husbandry systems in the EU are described. Overall, 19 highly relevant welfare consequences (WCs) were identified based on severity, duration and frequency of occurrence: 'bone lesions', 'cold stress', 'gastro-enteric disorders', 'group stress', 'handling stress', 'heat stress', 'isolation stress', 'inability to perform comfort behaviour', 'inability to perform exploratory or foraging behaviour', 'inability to avoid unwanted sexual behaviour', 'locomotory disorders', 'prolonged hunger', 'prolonged thirst', 'predation stress', 'restriction of movement', 'resting problems', 'sensory under- and overstimulation', 'soft tissue and integument damage' and 'umbilical disorders'. These WCs and their animal-based measures (ABMs) that can identify them are described in detail. A variety of hazards related to the different husbandry systems were identified as well as ABMs for assessing the different WCs. Measures to prevent or correct the hazards and/or mitigate each of the WCs are listed. Recommendations are provided on quantitative or qualitative criteria to answer specific questions on the welfare of broilers and related to genetic selection, temperature, feed and water restriction, use of cages, light, air quality and mutilations in breeders such as beak trimming, de-toeing and comb dubbing. In addition, minimal requirements (e.g. stocking density, group size, nests, provision of litter, perches and platforms, drinkers and feeders, of covered veranda and outdoor range) for an enclosure for keeping broiler chickens (fast-growing, slower-growing and broiler breeders) are recommended. Finally, 'total mortality', 'wounds', 'carcass condemnation' and 'footpad dermatitis' are proposed as indicators for monitoring at slaughter the welfare of broilers on-farm