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Monitoring natural populations is often a necessary step to establish the conservation status of species and to help improve management decisions. Nevertheless, many monitoring programs do not effectively address primary sources of variability in monitoring data, which ultimately may limit the utility of monitoring in identifying declines and improving management. To illustrate the importance of taking into account detectability and spatial variation, we used a recently proposed estimator of abundance (superpopulation estimator) to estimate population size of and number of young produced by the Snail Kite (Rostrhamus sociabilis plumbeus) in Florida. During the last decade, primary recovery targets set by the U.S. Fish and Wildlife Service for the Snail Kite that were based on deficient monitoring programs (i.e., uncorrected counts) were close to being met (by simply increasing search effort during count surveys). During that same period, the Snail Kite population declined dramatically (by 55% from 1997 to 2005) and the number of young decreased by 70% between 1992-1998 and 1999-2005. Our results provide a strong practical case in favor of the argument that investing a sufficient amount of time and resources into designing and implementing monitoring programs that carefully address detectability and spatial variation is critical for the conservation of endangered species.

National Wildlife Refuges (NWRs) in the United States play an important role in the adaptation of social-ecological systems to climate change, land-use change, and other global-change processes. Coastal refuges are already experiencing threats from sea-level rise and other change processes that are largely beyond their ability to influence, while at the same time facing tighter budgets and reduced staff. We engaged in workshops with NWR managers along the U.S. Atlantic coast to understand the problems they face from global-change processes and began a multidisciplinary collaboration to use decision science to help address them. We are applying a values-focused approach to base management decisions on the resource objectives of land managers, as well as those of stakeholders who may benefit from the goods and services produced by a refuge. Two insights that emerged from our workshops were a conspicuous mismatch between the scale at which management can influence outcomes and the scale of environmental processes, and the need to consider objectives related to ecosystem goods and services that traditionally have not been explicitly considered by refuges (e.g., protection from storm surge). The broadening of objectives complicates the decision-making process, but also provides opportunities for collaboration with stakeholders who may have agendas different from those of the refuge, as well as an opportunity for addressing problems across scales. From a practical perspective, we recognized the need to (1) efficiently allocate limited staff time and budgets for short-term management of existing programs and resources under the current refuge design and (2) develop long-term priorities for acquiring or protecting new land/habitat to supplement or replace the existing refuge footprint and thus sustain refuge values as the system evolves over time. Structuring the decision-making problem in this manner facilitated a better understanding of the issues of scale and suggested that a long-term solution will require a significant reassessment of objectives to better reflect the comprehensive values of refuges to society. We discuss some future considerations to integrate these two problems into a single framework by developing novel optimization approaches for dynamic problems that account for uncertainty in future conditions.

This paper uses microdata on balance sheets, trade, and the nationality of ownership of firms in France to investigate the effect of foreign multinationals on business cycle comovement. We first show that foreign affiliates, which represent a tiny fraction of all firms, are responsible for a high share of employment, value added, and trade both at the national and at the regional levels. We also show that the distribution of foreign affiliates across regions differs with the nationality of the parent. We then show that foreign affiliates increase the comovement of activities between their region of location and their country of ownership. Moreover, we find greater comovement among French regions that have a more similar composition in terms of the nationality of foreign affiliates. These findings suggest that a non-negligible part of business cycle comovement is driven by a few multinational companies, and that the international transmission of shocks is partly due to linkages between affiliates and their foreign parents.

Phenotypic plasticity, the ability of an individual to modify its phenotype according to the conditions it experiences, is a source of between-individual variation and a mechanism by which individuals can cope with environmental change. Plasticity is expected to evolve in response to environmental heterogeneity, such as seasonality and year-to-year variation. We aimed to characterize patterns of phenotypic change in morphological (body mass), life-history (reproductive success and litter size), and social (embeddedness) traits of female yellow-bellied marmots (Marmota flaviventris) in response to climatic and social variation. We used data collected over 36 years on a population of yellow-bellied marmots studied in Colorado. We used mixed effect models to explore phenotypically plastic responses and tested for individual variation in mean trait values (i.e., intercept) and in plasticity (i.e., slope). All examined traits were plastic, and the population’s average plastic response often differed between spatially distinct colonies that varied systematically in timing of snowmelt, among age classes, and between females with different previous reproductive experiences. Moreover, we showed individual differences in June mass and pup mass plasticity. We suggest that plasticity plays a key role buffering the effects of continuous changes in environmental conditions.

Summary 1 Habitat loss and fragmentation are major factors affecting vertebrate populations. A major effect of these habitat alterations is that they reduce movement of organisms. Despite the accepted importance of movement in driving the dynamics of many natural populations, movement of vertebrates in fragmented landscapes have seldom been estimated with robust statistical methods. 2 We estimated movement probabilities of snail kites Rosthramus sociabilis within the remaining wetlands in Florida. Using both radio-telemetry and banding information, we used a multistate modelling approach to estimate transition probabilities at two temporal scales (month; year) and multiple spatial scales. We examined kite movement among wetlands altered by three different levels of fragmentation: among wetlands separated by small physical barriers (e.g. road); among wetlands separated by moderate amount of matrix ( 15 km). 3 Kites moved extensively among contiguous wetlands (movement probability 0·29 per month), but significantly less among isolated wetlands (movement probability 0·10 per month). 4 Kites showed high levels of annual site fidelity to most isolated wetlands (probability ranged from 0·72 to 0·95 per year). 5 We tested the effects of patch size and interpatch distance on movement. Our modelling indicated an effect of both distance and patch size on juveniles’ movement (but not adult) when examining movements among fragments. 6 Only a small proportion of kites escaped a regional drought by moving to refugia (wetlands less affected by drought). Many individuals died after the drought. During drought adult survival dropped by 16% while juvenile survival dropped by 86% (possibly because juveniles were less likely to reach refugia). 7 We hypothesize that fragmentation may decrease kite's resistance to drought by restricting exploratory behaviour.

1. Factors affecting population birth sex ratio and variations of sex ratios within population in very long-lived animals are poorly known, apart for humans that have attracted much attention. We measured the age and sex structure of a population of a monogamous long-lived seabird, the wandering albatross Diomedea exulans , where reproductive performance of individuals is known, to examine factors affecting sex ratio variation and survival consequences of producing a particular sex. 2. The overall sex ratio at hatching is significantly biased toward the production of males. Very young and old parents tend to produce an excess of female offsprings, whereas intermediate-aged birds, which represent the bulk of the population, produce an excess of males. Low-quality parents (quality is measured as average breeding success over the cumulated past breeding life, and is not related to condition or age) produce more female chicks compared with high-quality parents that represent the bulk of the population. The combined effect of age and quality of parents produce an extensive sex ratio variation at the level of the population. 3. The survival of male and female parents is influenced differently by their quality and by the sex of offspring. Male parents die in larger numbers when rearing a female chick, whereas low-quality female parents have a lower survival, especially when they rear a male offspring, the sex needing higher parental investment. The differences between males and females parents' survival are probably due their contrasted investment in parental care. 4. After fledging, during the 5–8-year period of immaturity, there is a much higher mortality of males that balances the surplus of males at hatching and fledging and results in a similar number of males and females at the time of recruitment. However, the overall operational sex ratio is male biased due to the slightly higher mortality of adult females that results in an excess of old widowed males: excluding these post-reproductive males leads to an unbiased operational sex ratio. 5. These results show that sex ratio at hatching varies extremely with the age and phenotypic quality of parents, and lead to a complex age and sex structure of the population in this strictly monogamous long-lived species

Humans in strong social relationships are more likely to live longer because social relationships may buffer stressors and thus have protective effects. However, a shortcoming of human studies is that they often rely on self-reporting of these relationships. By contrast, observational studies of non-human animals permit detailed analyses of the specific nature of social relationships. Thus, discoveries that some social animals live longer and healthier lives if they are involved in social grooming, forage together or have more affiliative associates emphasizes the potential importance of social relationships on health and longevity. Previous studies have focused on the impact of social metrics on longevity in obligately social species. However, if sociality indeed has a key role in longevity, we might expect that affiliative relationships should also influence longevity in less social species. We focused on socially flexible yellow-bellied marmots (Marmota flaviventer) and asked whether female longevity covaries with the specific nature of social relationships. We quantified social relationships with social network statistics that were based on affiliative interactions, and then estimated the correlation between longevity and sociality using bivariate models. We found a significant negative phenotypic correlation between affiliative social relationship strength and longevity; marmots with greater degree, closeness and those with a greater negative average shortest path length died at younger ages. We conclude that sociality plays an important role in longevity, but how it does so may depend on whether a species is obligately or facultatively social.

International audience; Plasma electrolytic oxidation (PEO) of magnesium alloy is performed in NH4F and alkaline-silicate electrolytes within various waveforms of bipolar current pulses to investigate the role of the cathodic bias on both the growth mechanism of PEO layers and the behavior of micro-discharges. A particular attention is paid to cathodic micro-discharges and their ignition (or not) according to process conditions. Although cathodic micro-discharges have a detrimental effect on PEO layers, cathodic bias is necessary to improve the growth of oxide layers. Conditions that promote cathodic breakdown are discussed and a mechanism of layer cathodic breakdown is proposed. Cathodic micro-discharges, and to a greater extent the applied cathodic bias, influence the anodic breakdown coming immediately after, and therefore, the process behaviour during the anodic bias period.

In situ measurements using simultaneously Raman spectroscopy and high energy wide angles X-rays scattering (HE-WAXS) were carried out during uniaxial tensile tests of different polypropylene blends (neat isotactic polypropylene – iPP, high impact polypropylene – iPP/EPR, and high impact polypropylene filled by 7%wt of μ-talc particles – iPP/EPR + μ-talc) at various strain rates (5.10$^{−3}$ s$^{−1}$, 10$^{−3}$ s$^{−1}$ and 5.10$^{−4}$ s$^{−1}$). Tensile tests were performed using the VidéoTraction™ system to determine the true mechanical behavior of materials in a Representative Volume Element (RVE) where microstructural analyses by the both experimental techniques are obtained. Evolutions of the macromolecular chains orientation have been obtained live at the macromolecular and crystalline cell scales. Experimental results show both that over the course of adding charges in the iPP matrix or increasing the true strain rate, this major micromechanism of deformation of semi-crystalline polymers would be less and less important until its complete disappearance in case of iPP/EPR filled by μ-talc particles. Moreover, correlations made between both techniques evidence similar results over a wide range of true strains. However, measurements diverge at lower and higher strains due to singularities of each both techniques which are discussed in terms of experimental protocols and materials microstructure modifications (transient mesophase, volume damage). Finally, the determination of the true intrinsic mechanical behaviors show similar stress hardening slopes for the three studied iPP blends which means that they all present an highly fibrillar microstructure. The differences of macromolecular chains orientation levels between each material is then discussed in terms of analysis volume of both techniques which could be responsible of their lack of accuracy in case of filled polymers.

Multidisciplinary Design Optimization (MDO) problems can have a unique objective or be multi-objective. In this paper, we are interested in MDO problems having at least two conflicting objectives. This characteristic ensures the existence of a set of compromise solutions called Pareto front. We treat those MDO problems like Multi-Objective Optimization (MOO) problems. Actual MOO methods suffer from certain limitations, especially the necessity for their users to adjust various parameters. These adjustments can be challenging, requiering both disciplinary and optimization knowledge. We propose the use of the Adaptive Multi-Agent Systems technology in order to automatize the Pareto front obtention. ParetOMAS (Pareto Optimization Multi-Agent System) is designed to scan Pareto fronts efficiently, autonomously or interactively. Evaluations on several academic and industrial test cases are provided to validate our approach.

This paper analyzes the transfer pricing of multinational firms. We propose a simple framework in which intra-firm prices may systematically deviate from arm’s length prices for two motives: i) pricing to market, and ii) tax avoidance. Multinational firms may decide not to avoid taxes if the risk to be sanctioned is high compared to the tax gap. Using detailed French firm-level data on arm’s length and intra-firm export prices, we find that both mechanisms are at work. The sensitivity of intra-firm prices to foreign taxes is reinforced once we control for pricing-to-market determinants. Most importantly, we find almost no evidence of tax avoidance if we disregard exports to tax havens. Back-of-the-envelope calculations suggest that tax avoidance through transfer pricing amounts to about 1% of the total corporate taxes collected by tax authorities in France. The lion’s share of this loss is driven by the exports of 450 firms to ten tax havens. As such, it may be possible to achieve significant revenue increases with minimal cost by targeting enforcement.

The influence of wind patterns on behaviour and effort of free–ranging male wandering albatrosses ( Diomedea exulans ) was studied with miniaturized external heart–rate recorders in conjunction with satellite transmitters and activity recorders. Heart rate was used as an instantaneous index of energy expenditure. When cruising with favourable tail or side winds, wandering albatrosses can achieve high flight speeds while expending little more energy than birds resting on land. In contrast, heart rate increases concomitantly with increasing head winds, and flight speeds decrease. Our results show that effort is greatest when albatrosses take off from or land on the water. On a larger scale, we show that in order for birds to have the highest probability of experiencing favourable winds, wandering albatrosses use predictable weather systems to engage in a stereotypical flight pattern of large looping tracks. When heading north, albatrosses fly in anticlockwise loops, and to the south, movements are in a clockwise direction. Thus, the capacity to integrate instantaneous eco–physiological measures with records of largescale flight and wind patterns allows us to understand better the complex interplay between the evolution of morphological, physiological and behavioural adaptations of albatrosses in the windiest place on earth.

International audience; Plasma electrolytic oxidation (PEO) processing of EV 31 magnesium alloy has been carried out in fluoride containing electrolyte under bipolar pulse current regime. Unusual PEO cathodic micro-discharges have been observed and investigated. It is shown that the cathodic micro-discharges exhibit a collective intermittent behavior which is discussed in terms of charge accumulations at the layer/electrolyte and layer/metal interfaces. Optical emission spectroscopy is used to determine the electron density (typ. 10 15 cm-3) and the electron temperature (typ. 7500 K) while the role of F-anions on the appearance of cathodic micro-discharges is pointed out. Plasma Electrolytic Oxidation (PEO) is a promising plasma-assisted surface treatment of light metallic alloys (e.g. Al, Mg, Ti). Although the PEO process makes it possible to grow oxide coatings with interesting corrosion and wear resistant properties, the physical mechanisms of coating growth are not yet completely understood. Typically, the process consists in applying a high voltage difference between a metallic piece and a counter-electrode which are both immersed in an electrolyte bath. Compare to anodizing, the main differences concern the electrolyte composition and the current and voltage ranges which are at least one order of magnitude higher in PEO 1. These significant differences in current and voltage imply the dielectric breakdown and consequently the appearance of micro-discharges on the surface of the sample under processing. Those micro-discharges are recognized as being the main contributors to the formation of a dielectric porous crystalline oxide coating. 2 Nevertheless, the breakdown mechanism that governs the appearance of those micro-discharges is still under investigation. Hussein et al. 3 proposed a mechanism with three different plasma formation processes based on differences in plasma chemical composition. The results of Jovović et al. 4,5 concerning physical properties of the plasma seem to corroborate this mechanism, and also point out the importance of the substrate material in the plasma composition. 6 Compared with DC conducted PEO process, using a bipolar pulsed DC or AC current supply gives supplementary control latitude through the current waveform parameters. The effect of these parameter on the micro-discharges behavior has been investigated in several previous works. 2,3,7,8 One of the main results of these studies is the absence of micro-discharge during the cathodic current half-period. 9-11 Even if the cathodic half-period has an obvious effect on the efficiency of PEO as well as on the coating growth and composition, the micro-plasmas appear only in anodic half-period. Sah et al. 8 have observed the cathodic breakdown of an oxide layer but at very high current density (10 kA.dm-²), and after several steps of sample preparation. Several models of micro-discharges appearance in AC current have already been proposed. 1,2,8,12,13 Though cathodic micro-discharges have never been observed within usual process conditions, the present study aims at defining suitable conditions to promote cathodic micro-discharges and at studying the main characteristics of these micro-plasmas.

10th International Symposium on Electrochemical Methods in Corrosion Research (EMCR), Maragogi, BRAZIL, NOV 18-23, 2012; International audience; In the framework of the new ecological regulations, micro-arc oxidation (MAO) appears as an alternative to usual processes in the field of corrosion protection of Mg alloys. In this work, the initial stages of anodic layer growth in KOH-based electrolytes are studied up to and beyond the initiation of the micro-arc regime. The properties of the first anodized film preceding the occurrence of the dielectric breakdown (corresponding to the start of the micro-arc regime) are mainly determined by the incorporation of additives (fluorides or silicates) in the film, as shown by in situ electrochemical measurements. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and micro-Raman spectroscopy reveal both the change of morphology and chemical state of silicate and fluoride in the anodized layer before and after the micro-arc regime. In terms of electrochemical behaviour, investigated by stationary methods and electrochemical impedance spectroscopy (EIS) in reference corrosive water, the anodic film grown in the silicate medium provides the best corrosion resistance thanks to a thick layer containing Mg2SiO4, whose degradation products seal the porosities of the coating.

We study the extent to which the structure of an exporter's portfolio of buyers affects the volatility of its sales, volatility of bilateral exports. In our model, diversifying sales across a larger number of partners reduces the firm's exposure to idiosyncratic demand shocks, thus the volatility of its sales. Being connected with importers that also interact with other sellers creates comovements in sales across sellers. We show that both elements can generate "granular" fluctuations in aggregate exports. Based on highly detailed export data, we show that exporters are little diversified in sales and that trade networks are highly connected across exporters. This participates to explaining the high volatility of bilateral exports in our data.

A conceptual framework is provided for considering the threshold concept in natural resource management and conservation. We define three kinds of thresholds relevant to management and conservation. Ecological thresholds are values of system state variables at which small changes bring about substantial or specified changes in system dynamics. They are frequently incorporated into ecological models used to project system responses to management actions. Utility thresholds are components of management objectives and are values of state or performance variables at which small changes yield substantial changes in the value of the management outcome. Decision thresholds are values of system state variables at which small changes prompt changes in management actions in order to reach specified management objectives. Decision thresholds are derived from the other components of the decision process. We advocate a structured decision making (SDM) approach within which the following components are identified: objectives (possibly including utility thresholds), potential actions, models (possibly including ecological thresholds), monitoring program, and a solution algorithm (which produces decision thresholds). Adaptive resource management (ARM) is described as a special case of SDM developed for recurrent decision problems that are characterized by uncertainty. We believe that SDM, in general, and ARM, in particular, provide good approaches to conservation and management. Use of SDM and ARM also clarifies the distinct roles of ecological thresholds, utility thresholds, and decision thresholds in informed decision processes.

In this chapter, we demonstrate the application of the various classes of thresholds, detailed in earlier chapters and elsewhere, via an actual but simplified natural resource management case study. We intend our example to provide the reader with the ability to recognize and apply the theoretical concepts of utility, ecological and decision thresholds to management problems through a formalized decision-analytic process. Our case study concerns the management of human recreational activities in Alaska’s Denali National Park, USA, and the possible impacts of such activities on nesting Golden Eagles, Aquila chrysaetos. Managers desire to allow visitors the greatest amount of access to park lands, provided that eagle nesting-site occupancy is maintained at a level determined to be acceptable by the managers themselves. As these two management objectives are potentially at odds, we treat minimum desired occupancy level as a utility threshold which, then, serves to guide the selection of annual management alternatives in the decision process. As human disturbance is not the only factor influencing eagle occupancy, we model nesting-site dynamics as a function of both disturbance and prey availability. We incorporate uncertainty in these dynamics by considering several hypotheses, including a hypothesis that site occupancy is affected only at a threshold level of prey abundance (i.e., an ecological threshold effect). By considering competing management objectives and accounting for two forms of thresholds in the decision process, we are able to determine the optimal number of annual nesting-site restrictions that will produce the greatest long-term benefits for both eagles and humans. Setting a utility threshold of 75 occupied sites, out of a total of 90 potential nesting sites, the optimization specified a decision threshold at approximately 80 occupied sites. At the point that current occupancy falls below 80 sites, the recommended decision is to begin restricting access to humans; above this level, it is recommended that all eagle territories be opened to human recreation. We evaluated the sensitivity of the decision threshold to uncertainty in system dynamics and to management objectives (i.e., to the utility threshold).

The explosion of the Deepwater Horizon drilling platform created the largest marine oil spill in U.S. history. As part of the Natural Resource Damage Assessment process, we applied an innovative modeling approach to obtain upper estimates for occupancy and for number of manatees in areas potentially affected by the oil spill. Our data consisted of aerial survey counts in waters of the Florida Panhandle, Alabama and Mississippi. Our method, which uses a Bayesian approach, allows for the propagation of uncertainty associated with estimates from empirical data and from the published literature. We illustrate that it is possible to derive estimates of occupancy rate and upper estimates of the number of manatees present at the time of sampling, even when no manatees were observed in our sampled plots during surveys. We estimated that fewer than 2.4% of potentially affected manatee habitat in our Florida study area may have been occupied by manatees. The upper estimate for the number of manatees present in potentially impacted areas (within our study area) was estimated with our model to be 74 (95%CI 46 to 107). This upper estimate for the number of manatees was conditioned on the upper 95%CI value of the occupancy rate. In other words, based on our estimates, it is highly probable that there were 107 or fewer manatees in our study area during the time of our surveys. Because our analyses apply to habitats considered likely manatee habitats, our inference is restricted to these sites and to the time frame of our surveys. Given that manatees may be hard to see during aerial surveys, it was important to account for imperfect detection. The approach that we described can be useful for determining the best allocation of resources for monitoring and conservation.

Dans le cadre de reflexions sur le droit a l’Etat, il est possible de s’interroger sur l’existence d’un droit au territoire, corollaire du premier. La reponse a cette interrogation s’avere plutot negative, qu’il s’agisse aussi bien de la reconnaissance d’un nouveau territoire, que du maintien d’un territoire existant. Neanmoins, l’analyse montre que les choses sont moins evidentes qu’il n’y parait. D’un cote, d’un point de vue strictement juridique, s’il existe des limites fixees par la Constitution et par la loi, celles-ci se revelent largement contingentes. De l’autre cote, d’un point de vue sociopolitique, le droit au territoire semble decouler d’une realite, celle d’une multiplication de territoires, dont l’identite et l’autonomie ne cessent de se renforcer.

Individuals of many species produce distinctive vocalizations that may relay potential information about the signaller. The alarm calls of some species have been reported to be individually specific, and this distinctiveness may allow individuals to access the reliability or kinship of callers. While not much is known generally about the heritability of mammalian vocalizations, if alarm calls were individually distinctive to permit kinship assessment, then call structure should be heritable. Here, we show conclusively for the first time that alarm call structure is heritable. We studied yellow-bellied marmots ( Marmota flaviventris ) and made nine quantitative measurements of their alarm calls. With a known genealogy, we used the animal model (a statistical technique) to estimate alarm call heritability. In juveniles, only one of the measured variables had heritability significantly different from zero; however, most variables had significant maternal environmental effects. By contrast, yearlings and adults had no significant maternal environmental effects, but the heritability of nearly all measured variables was significantly different from zero. Some, but not all of these heritable effects were significantly different across age classes. The presence of significantly non-zero maternal environmental effects in juveniles could reflect the impact of maternal environmental stresses on call structure. Regardless of this mechanism, maternal environmental effects could permit kinship recognition in juveniles. In older animals, the substantial genetic basis of alarm call structure suggests that calls could be used to assess kinship and, paradoxically, might also suggest a role of learning in call structure.

International audience; The plasma electrolytic oxidation (PEO) of aluminium alloys is investigated for different electrical working conditions using a pulsed bipolar current supply. A particular attention is paid to the effect of the anodic current density (from 10 to 90 A dm(-2)) and current pulse frequency (from 100 to 900 Hz) on the resulting oxide layer. Micro-discharges are characterized during the process by means of fast video imaging with a time and a space resolution of 8 mu s and 0.017 mm(2), respectively. Correlations are established between the micro-discharge characteristics (surface density, lifetime and size) and the elaborated oxide layers (morphology, growth rate and surface roughness). The highest coating growth rate measured (2.1 mu m min(-1)) is achieved with the combination of the highest current density (75.7 A dm(-2)) and the highest current pulse frequency (900 Hz). Within these specific current conditions it is concluded that the detrimental effects of numerous micro-discharges are minimized. The results also show that the surface roughness may be largely affected by the presence of long-lived and large micro-discharges which develop over the processed surface. The strongest micro-discharges (live duration up to 0.3 ms and cross-sectional area up to 1 mm(2)) are mainly observed with the combination of the highest current density (75.7 A dm(-2)) and the lowest current pulse frequency (100 Hz).

We use the results of a survey conducted on a sample of 3,013 exporting firms located in 5 EMU countries to explore the link between the invoicing currency of exports, firm size, and hedging. About 90% of firms in the sample invoice exports in their (producer) currency. Large firms are more likely to use another currency. The aggregate use of the euro is thus 15 percentage points lower when firms are weighted by their size than for the average firm. This heterogeneity is robust to controlling for determinants of the invoicing choice stressed by the literature. We however show that large firms and firms pricing in another currency as the euro are also more likely to hedge against exchange rate risk. An IV estimation shows the causal impact of access to hedging on the choice of the invoicing currency. We find (large) firms having access to hedging being more likely to invoice in the importer’s currency.

Unintended effects of recreational activities in protected areas are of growing concern. We used an adaptive-management framework to develop guidelines for optimally managing hiking activities to maintain desired levels of territory occupancy and reproductive success of Golden Eagles (Aquila chrysaetos) in Denali National Park (Alaska, U.S.A.). The management decision was to restrict human access (hikers) to particular nesting territories to reduce disturbance. The management objective was to minimize restrictions on hikers while maintaining reproductive performance of eagles above some specified level. We based our decision analysis on predictive models of site occupancy of eagles developed using a combination of expert opinion and data collected from 93 eagle territories over 20 years. The best predictive model showed that restricting human access to eagle territories had little effect on occupancy dynamics. However, when considering important sources of uncertainty in the models, including environmental stochasticity, imperfect detection of hares on which eagles prey, and model uncertainty, restricting access of territories to hikers improved eagle reproduction substantially. An adaptive management framework such as ours may help reduce uncertainty of the effects of hiking activities on Golden Eagles.

Nowadays, thermoplastic polymers do not cease to attract the interest of the industrialists as steel / polymer composites for various applications in several domains, such as the automotive and the packaging. The ratio between their wide range of thermo‐mechanical properties and their low weight density make these materials a real alternative for the current solutions for the lightening and the reinforcement of structural pieces. Likewise, their working facility is a major asset for performing parts of complex geometry. In this paper, we highlight the narrow relationship between the microstructure of a small impact isotactic polypropylene film, either filled or not by mineral particles (calcite), and its behaviour towards shrinkage which can occur during thermal treatments above its melting temperature. This phenomenon of shrinkage is characterized by dimensional instabilities which can in particular, affect the life cycle of the material. Indeed, they may induce the partial delamination of the steel sheet which is consequently exposed to various environmental aggressions. Corrosive behaviour can occur and cause early breakdown of the material. Influences of the extrusion and stamping processes on the microstructure and the shrinkage are presented. The macromolecular chains orientation of the crystalline phase, the volume damage and the heating parameters are studied, and show a real impact on the phenomenon magnitude. An experimental setup was developed at the laboratory to measure in real‐time and with good precision, the displacements induced by shrinkage and the microstructural evolution of the polymer film during different thermal cycles. Finally, an empirical law allowing the shrinkage prediction is presented, taking into account the deformation value and the initial degree of chains orientation. These studies and their results have led to the determination of the optimal parameters settings for the different conformation processes with the aim of reducing the maximum of shrinkage.

This paper presents the use of a Raman spectrometer coupled to a machine VideoTraction. For uniaxial tensile mechanical testing, Raman spectra are realized, that by using spectral signatures date back to the microstructure of the material: isotactic polypropylene. Here we are particularly interested in analyzing the orientation of the chains of the crystalline phase during the elastic recovery.

What is the impact of low-wage countries' competition on the quality of high-wage countries' exports? To answer this question, we develop a new method that uses firm-level data to measure quality changes in sectoral exports. Over 1995-2005, we measure a 11% increase in the mean quality of France's aggregate exports, driven by a reallocation of demand in favor of higher quality producers. The phenomenon is significantly more pronounced in markets where the penetration of developing countries has increased while it is negative where firms face increased competitive pressures from high-wage countries. These results are consistent with within-product specialization along the vertical dimension. They suggest that, over the period, France has specialized in the production of higher quality goods. In our data, around one fifth of the measured quality improvement in France's aggregate exports is attributable to low-wage countries' competition. In turn, its increasing specialization in higher quality goods has limited France's market share loss over the period.

Several studies of large mammals report no direct reproductive costs for females. Individual heterogeneity may hide fitness costs of reproduction, but mothers could also transfer some costs to their offspring. Using data on 442 lambs weaned by 146 bighorn sheep (Ovis canadensis) ewes at Ram Mountain, Alberta, we studied how reproductive effort varied with environmental and maternal conditions. During summer, lactating ewes should gain enough mass to survive the winter and to support their next gestation, while nursing their current lamb. We measured reproductive effort as summer mass gain by lambs corrected for maternal mass in June and maternal mass gain during summer. Females lowered their reproductive effort when population density increased and if they had weaned a lamb the previous year. A reduction in reproductive effort led to lower winter survival by lambs. Bighorn ewes have a conservative reproductive tactic and always favor their own body condition over that of their lambs. When resources are limited, ewes appear to transfer reproductive costs to their lambs, as expected from the much greater relative fitness consequences of a reduction in maternal than in offspring survival.

The recent development of statistical models such as dynamic site occupancy models provides the opportunity to address fairly complex management and conservation problems with relatively simple models. However, surprisingly few empirical studies have simultaneously modeled habitat suitability and occupancy status of organisms over large landscapes for management purposes. Joint modeling of these components is particularly important in the context of management of wild populations, as it provides a more coherent framework to investigate the population dynamics of organisms in space and time for the application of management decision tools. We applied such an approach to the study of water hole use by African elephants in Hwange National Park, Zimbabwe. Here we show how such methodology may be implemented and derive estimates of annual transition probabilities among three dry-season states for water holes: (1) unsuitable state (dry water holes with no elephants); (2) suitable state (water hole with water) with low abundance of elephants; and (3) suitable state with high abundance of elephants. We found that annual rainfall and the number of neighboring water holes influenced the transition probabilities among these three states. Because of an increase in elephant densities in the park during the study period, we also found that transition probabilities from low abundance to high abundance states increased over time. The application of the joint habitat-occupancy models provides a coherent framework to examine how habitat suitability and factors that affect habitat suitability influence the distribution and abundance of organisms. We discuss how these simple models can further be used to apply structured decision-making tools in order to derive decisions that are optimal relative to specified management objectives. The modeling framework presented in this paper should be applicable to a wide range of existing data sets and should help to address important ecological, conservation, and management problems that deal with occupancy, relative abundance, and habitat suitability.

This paper presents a theoretical discussion and an empirical investigation of the impact of distance on the spatial pricing policy of exporting firms. The theoretical part points out the importance of transport costs formulation to determine how distance impacts fob prices. Assuming additive or iceberg transport costs might imply opposite predictions concerning this relationship. The empirical analysis is based on French export data providing us with bilateral export unit values at the firm and product level. The main empirical result is that French exporters set higher prices toward the more remote markets. This finding goes against the predictions of the main models of international trade (with or without quality) predicting either a nil or a negative impact of distance on prices at the firm level. It also questions the use of iceberg transport costs. A way to reconcile theory with the data is to introduce additive transport costs.

Perturbation analysis is a powerful tool to study population and community dynamics. This article describes expressions for sensitivity metrics reflecting changes in equilibrium occupancy resulting from small changes in the vital rates of patch occupancy dynamics (i.e., probabilities of local patch colonization and extinction). We illustrate our approach with a case study of occupancy dynamics of Golden Eagle (Aquila chrysaetos) nesting territories. Examination of the hypothesis of system equilibrium suggests that the system satisfies equilibrium conditions. Estimates of vital rates obtained using patch occupancy models are used to estimate equilibrium patch occupancy of eagles. We then compute estimates of sensitivity metrics and discuss their implications for eagle population ecology and management. Finally, we discuss the intuition underlying our sensitivity metrics and then provide examples of ecological questions that can be addressed using perturbation analyses. For instance, the sensitivity metrics lead to predictions about the relative importance of local colonization and local extinction probabilities in influencing equilibrium occupancy for rare and common species.

This paper describes the impact of the Euro on i) the level, ii) the evolution and iii) the dispersion of trade prices. This empirical analysis relies on firm level data about French exports over the period 1995-2005. We find that the elimination of exchange rate fluctuations reduces the pricing to market behavior of French exporters. At the beginning of the EMU, we also observe an increase in aggregate prices for sales in the Euro zone. This price increase does not compensate for the aggregate price gap between cheaper EMU markets and more expensive non-EMU countries. Last we find that the Euro has affected firms’ pricing strategies leading to a reduction of the price dispersion inside the Euro zone.

This report presents a global constraint that enforces rules written in a language based on arithmetic and first-order logic to hold among a set of objects. In a first step, the rules are rewritten to Quantifier-Free Presburger Arithmetic (QFPA) formulas. Secondly, such formulas are compiled to generators of k-dimensional forbidden sets. Such generators are a generalization of the indexicals of cc(FD). Finally, the forbidden sets generated by such indexicals are aggregated by a sweep-based algorithm and used for filtering. The business rules allow to express a great variety of packing and placement constraints, while admitting efficient and effective filtering of the domain variables of the k-dimensional object, without the need to use spatial data structures. The constraint was used to directly encode the packing knowledge of a major car manufacturer and tested on a set of real packing problems under these rules, as well as on a packing-unpacking problem. Published in Lecture Notes in Computer Science; Volume 5202

Export and import price indices are useful instruments in international economics. We document here TradePrices, our database of aggregated and sectoral trade price indices for all countries, computed using unit values given by BACI, the CEPII’s database of international trade at the product-level covering the period 1995-2004. Its rich country dimension allow an international comparison of prices evolutions. We compute “common” Laspeyres and Paasche indices but also “superlative” Fisher and Tornqvist indices, in both chained and fixed-base forms (chained Laspeyres and Paasche are also provided in their geometric form). In a first part, we discuss the characteristics of these different aggregation methods. In particular, we highlight the links between statistical methods and economical assumptions about implicit elasticity of substitution between goods. In a second step we describe the data. An exhaustive sensitivity analysis is done in order to determine the appropriate way to deal with technical difficulties, such as the treatment of measurement errors in bilateral unit values. Finally, this paper provides some stylized facts illustrating the necessity to provide a trade price database allowing international comparison and the usefulness of both aggregated and sectoral trade price indices to study international economics. TradeP rices database and SAS programs are freely available online, offering to users the possibility to choose the most accurate index for each particular purpose.

International audience; This review contains a theoretical background of optical emission spectroscopy and some selected examples of issues in the field of atmospheric plasmas. It includes elements like line broadening, emission of continua and molecules, radiation models, etc. Modernized expressions figuring the terms hidden in global constants where cgs units prevail are given together with restrictions of use. Easy-to-use formulas are provided to give access to essential plasma parameters.

Studies on the response of wildlife to human disturbance generally focus on demographic changes or on physiological and behavioural modifications directly related to stress response. Yet fewer studies have explored whether the distribution of individual animals in response to human disturbance is influenced by temperament. Temperament represents the consistency of responses of individuals in reaction to novel or challenging situations. Individuals are thus assumed to express highly consistent behaviour-hormonal response under specific stress conditions. In this study, we investigate the relations between exploration, grooming-scanning continuum, emotionality, and docility of individual Eastern chipmunks (Tamias striatus) and location of their burrow respective to frequentation by humans. We then assess the relationship between cortisol accumulated in the hair and both temperament and frequentation by humans. Explorative or docile chipmunks were more common in frequented areas. Hair cortisol increased with docility, but was not related to human frequentation. These results indicate that temperament may cause animals to distribute themselves in a non-random way in response to human disturbance. Integrating temperament into studies of the stress response of wildlife to humans could therefore help us understand the impact of tourism on wildlife.

A new sampler is presented which uses osmotic pumps that continuously monitor the chemistry and flow rate of fluids emanating from porous sediment via diffuse flow into the ocean. Flow rates as low as few cm/yr are determined using tracers injected as a point source, and by continuously sampling the sediment pore water and studying variability in tracer concentrations with time. Sampling can be conducted at various depths in the sediment and distances from the injection port, thereby allowing determination of the flow field in the shallow sub-seafloor sediments. The continuously sampled pore fluids are also analyzed for their chemistry which, combined with the flow rate data, yields the fluxes of chemical species from the sediment into the ocean.

In mammals, prenatal exposure to sex steroid hormones may have profound effects on later behavior and fitness and have been reported under both laboratory and field conditions. Anogenital distance is a non-invasive measure of prenatal exposure to sex steroid hormones. While we know that intra-uterine position and litter sex ratio influence anogenital distance, there are other, heretofore unstudied, factors that could influence anogenital distance, including maternal effects. We capitalized on a long-term study of wild yellow-bellied marmots (Marmota flaviventris) to study the importance of maternal effects on explaining variation in anogenital distance and found significant effects. The strength of these effects varied annually. Taken together, our data highlights the strong variability due to environmental effects, and illustrates the importance of additive genetic and maternal genetic effects on neonatal anogenital distance. We suspect that, as others apply recently popularised quantitative genetic techniques to study free-living populations, such effects will be identified in other systems, DTB was supported by the National Geographic Society, UCLA (Faculty Senate and the Division of Life Sciences), a Rocky Mountain Biological Laboratory research fellowship, and by the NSF (IDBR-0754247 and DEB-1119660 to DTB, as well as DBI 0242960 and 0731346 to the Rocky Mountain Biological Laboratory). RM was supported by postdoctoral fellowships from the Spanish Ministerio de Innovación y Ciencia and the Fulbright program. JGAM was supported by a FRQNT postdoctoral fellowship and the NSF

Many species of large bird fly together in formation, perhaps because flight power demands and energy expenditure can be reduced when the birds fly at an optimal spacing, or because orientation is improved by communication within groups. We have measured heart rates as an estimate of energy expenditure in imprinted great white pelicans (Pelecanus onocrotalus) trained to fly in 'V' formation, and show that these birds save a significant amount of energy by flying in formation. This advantage is probably a principal reason for the evolution of flight formation in large birds that migrate in groups.