Éditeur(s) : American Geophysical Union
Résumé : [1] Extreme weather events such as tropical cyclones are difficult to observe with conventional means. Satellite-based observations provide essential measurements of key parameters governing tropical cyclones. They are critical for short-term forecasting. Radiometers onboard the Defense Meteorological Satellite Program satellite series, WindSat and Tropical Rainfall Measuring Mission satellites, scatterometers onboard the ERS, ADEOS, and QuikScat satellites offer unprecedented synoptic observations of surface wind and atmospheric liquid water content, revealing the storm structures with good accuracy. However, satellite estimates do not provide direct measurements of geophysical parameters and can suffer from limitations linked to the sensors characteristics, such as the signal wavelength and polarization or the measurement incidence angle. For example, measurements at Ku band are strongly affected by rain. Still, each observing system can offer specific information that can be combined with the others. In particular, we highlight the capabilities of dual-frequency altimeter to provide very high resolution measurements of rain rate, surface wind speed, and wave characteristics. A method is proposed to obtain continuous along-track 5 km resolution measurements of these parameters in the tropical cyclone Isabel. The results shows that dual-frequency altimeters can provide useful information to complement and validate the operational fields provided by the atmospheric numerical models and by NOAA observing systems.
Journal of Geophysical Union - Research C - Oceans (0148-0227) (American Geophysical Union), 2006 , Vol. 111 , N. C1 , P. NIL_38-NIL_50

Droits : 2006 American Geophysical Union
http://archimer.ifremer.fr/doc/2006/publication-1033.pdf
DOI:10.1029/2005JC003068
http://archimer.ifremer.fr/doc/00000/1033/

Éditeur(s) : Colloque IMBC - International Marine Biotechnology Conference
Résumé : Since 1997, a new pathology seasonally occurs in new caledonian shrimp farms during the warm season. Diseased Litopenaeus stylirostris shrimp suffer from a systemic vibriosis which was attributed to highly pathogenic Vibrio nigripulchritudo. At the present time, only two farms among 17 are affected by the so called "summer syndrome". In such a context it appears urgent to develop reliable diagnostic tools to detect V. nigripulchritudo strains and to differentiate highly virulent strains from non virulent ones in order to understand the mechanisms of infection and overcome disease spreading. Multilocus Sequencing Typing (MLST) analysis on 24 bacterial strains isolated in geographically distinct shrimp farms highlighted the existence of a cluster A containing only strains displaying moderate to high virulence. Since experimental infection procedure for virulence status determination is material intensive and time consuming, and MLST method not accurate enough to inform on the virulence status of strains, it appeared of great interest to develop other diagnostic tools. Two phylogenetically closed strains, one highly virulent SFn1 and the other non-virulent SFn118 were selected in order to characterize genes specific of the virulent strain by Substractive Suppression Hybridization (SSH). Firstly, a total of 622 DNA fragments specific of SFn1 were sequenced, characterized and further used as probes in a DNA macroarray. Testing 24 strains, hybridization profiles were found to be strongly correlated with both MLST genotypes and bacterial virulence status. A total of 96 representative probes were secondly selected to validate macroarray results on 34 more additionnal strains, allowing identification of genetic markers of virulence. Most of DNA fragments specific of highly virulent strains associated to summer syndrome were found to be bore by a plasmid successfully isolated in the laboratory. In next future, these results would permit the development of relevant diagnostic tools useful for accurate epidemiological survey of the summer syndrome.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/acte-3398.pdf
http://archimer.ifremer.fr/doc/00000/3398/

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
Congenital anomalies are the main causes of preterm and neonatal mortality and morbidity. We investigated the association between congenital anomalies and mothers' exposure to air pollution during pregnancy by combining risk estimates for a variety of air pollutants (SO2, NO2, PM10, PM2.5, CO and O3) and anomaly defect outcomes. Seventeen articles were included in the systematic review and thirteen studies were taken into account in the meta-analysis. Combined estimated were calculated separately according to whether the exposure metric was continuous or categorical. Only one significant combination was; NO2 concentrations were significantly associated with coarctation of the aorta (OR = 1.20 per 10 ppb, 95% CI, (1.02, 1.41)). This finding could stem from strong heterogeneity in study designs. Improved exposure assessment methods, in particular more accurate spatial measurements or modeling, standardized definition of cases and of better control of confounders are highly recommended for future congenital anomalies research in this area.
ISSN: 1660-4601

hal-01118609
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118609
PUBMED : 25089772
DOI : 10.3390/ijerph110807642
PUBMEDCENTRAL : PMC4143824

Éditeur(s) : HAL CCSD
Résumé : International audience
Radiocarbon dating and "old wood problem" in the Antilles : the state of the artAmong the many effects that may distort the interpretation of radiocarbon dates are those for which the age of the archaeological event is different from the radiocarbon age of the sample or "14C event" age. This type of problem arises in many cases, notably in the "old wood effect”, and occurs in various regions of the world where very long-lived trees species are common. In the Caribbean anthracological studies indicate a very high frequency of some indigenous centuries-old species such as Guaiacum, Guaiacum officinale L. However the absence of tree-ring data in humid tropical zones deprives us of an accurate inventory of long-lived species and especially the assessment of their longevity. Here we present measurements which enable us to estimate the longevity of archaeological Guaiacum wood posts. They highlight a gap of several centuries between wood from the outer edge and the heart of the tree. This example illustrates the additional uncertainty that can result from dating archeological events when dates are realized on unidentified botanical species from which the area that was sampled is unknown. Another source of error could arise from the use of rot-proof dead wood as fuel if we take into consideration that major hurricanes can produce large amounts of dead wood that may be collected for decades, even centuries. To improve chronometric data used in archaeological interpretations, it is necessary to ensure the quality of the dating process by following a protocol similar to those used in other regions of the world based on a better understanding of the material to be dated by preliminary identifications of wood samples: species, anatomical part, wood moisture content (unseasoned or seasoned).
Radiocarbono y "problema madera vieja", que data de las Antillas: estado del arteEntre los muchos efectos que pueden distorsionar la interpretación de fechas de radiocarbono, destacan aquellos para los que la edad de la prueba arqueológica es diferente de la edad de radiocarbono de la muestra, o la edad del "evento de radiocarbono." Este tipo de problema se presenta en muchos casos, especialmente uno llamado "efecto madera vieja." Esto se refleja en diversas regiones del mundo donde las especies de plantas de mucha longevidad son comunes. En el Caribe, los estudios antracológicos disponibles indican una muy alta frecuencia de algunas especies autóctonas como el guayaco, Guaiacum officinale L. Sin embargo, la casi ausencia de datos de anillos de árboles en los trópicos húmedos, nos impide realizar un inventario exacto de especies de mucha longevidad y sobre todo la evaluación de la longevidad. Algunas de las pruebas presentadas aquí permitieron una estimación de la longevidad de de unos postes de guayaco de origen arqueológico. Ponen de manifiesto una brecha de varios siglos entre las partes externas y el corazón del tronco. Este ejemplo ilustra la aparición de una incertidumbre adicional en la datación de los eventos arqueológicos cuando no conocemos la especie botánica y tampoco la zona de la muestra en el árbol. Otra fuente de error puede surgir de la utilización de la madera muerta de calidad duradera como combustible ya que los grandes huracanes pueden producir grandes cantidades de madera muerta, que puede ser requerida durante décadas, incluso siglos. Para mejorar los datos cronométricos utilizados en interpretaciones arqueológicas, es necesario asegurarse de la calidad de las fechas, y por lo tanto seguir un protocolo similar a los utilizados en otras regiones fundado en una mejor comprensión de los elementos: especie, parte anatómica, humedad de la madera usada (verde o seco).
Parmi les nombreux effets susceptibles de fausser l’interprétation des datations par le radiocarbone, figurent ceux pour lesquels l’âge de l’événement archéologique est différent de l’âge radiocarbone de l’échantillon, ou âge de l’« événement radiocarbone ». Ce type de problème se pose dans de nombreux cas, en particulier celui dénommé « effet vieux bois ». Cette question est prise en compte dans diverses régions du monde où des espèces végétales très longévives sont fréquentes. Dans les Antilles les études anthracologiques disponibles indiquent une fréquence très importante de certaines espèces autochtones multiséculaires dont le gaïac, Guaiacum officinale L.. Cependant, la quasi absence de données dendrochronologiques dans la zone tropicale humide, nous privent d’un inventaire précis des espèces longévives et surtout de l’évaluation de leur longévité. Quelques tests présentés ici ont permis une estimation de la longévité de poteaux d’origine archéologique en bois de gaïac. Ils mettent en évidence un décalage de plusieurs siècles entre les parties externes et le cœur du tronc. Cet exemple illustre l’apparition d’une incertitude supplémentaire dans la datation de l’événement archéologique lorsque que l’on ne connaît ni l’espèce botanique ni la zone de prélèvement dans l’arbre. Une autre source d’erreur pourrait provenir de l’utilisation de bois mort de qualité très durable comme combustible, sachant que les grands cyclones peuvent produire d’importantes quantités de bois mort susceptible d’être récolté pendant des décennies, voire des siècles. Afin d’améliorer les données chronologiques utilisées dans les interprétations archéologiques, il apparaît nécessaire de s’assurer de la qualité des datations, et donc de suivre un protocole similaire à ceux utilisés dans d’autres régions basé sur une meilleure connaissance des éléments datés : espèce, partie anatomique, humidité du bois utilisé (vert ou sec).
Puerto Rico 2013 : Actas del 25to Congreso Internacional de Arqueología del Caribe - Proceeding of the 25th International Congress for Caribbean Archeology - Comptes rendus des communications du 25e Congrés International de l'Archéologie de la Caraïbe
San-Juan, Puerto Rico

hal-01198567
https://hal.archives-ouvertes.fr/hal-01198567
https://hal.archives-ouvertes.fr/hal-01198567/document
https://hal.archives-ouvertes.fr/hal-01198567/file/Stouvenot%20et%20al.%202015.%20Effet%20vieux%20bois%20radiocarbone%20Antilles%20HD.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Signatures provide a convenient and widely accepted method of authentication, however they are prone to attack by forgery. This can be mitigated to an extent by analysing both the static and dynamic biometric aspects of construction, however the possibly for accurate forgery from a static image of a genuine signature still exists. In this study we explore initial forgery accuracy of a range of genuine signatures and how accuracy changes as a forger receives feedback from a commercial signature engine in terms of a 'match score'. We also explore the effects of genuine signature complexity on forgery performance alongside the image size of the genuine signature to be forged. Our results show that forgers are able improve performance over time on simple signatures (including those with less pen travel distance) and that a magnified genuine sample enables more accurate forgery for these class of signatures. More complex signatures result in lower forged verification scores and irregular patterns of improvement across the five forgeries. Overall verification match scores were typically less than 80% for most attempts regardless of signature complexity, thus indicating the resilience of dynamic systems to unskilled forgery attempts.
17th Biennial Conference of the International Graphonomics Society
Pointe-à-Pitre, Guadeloupe

hal-01165763
https://hal.univ-antilles.fr/hal-01165763
https://hal.univ-antilles.fr/hal-01165763/document
https://hal.univ-antilles.fr/hal-01165763/file/IGS_2015_submission_1.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Primary spontaneous pneumothorax (PSP) is common and affects young and active patients. Guidelines are accurate about diagnosis and treatment indications, but the initial optimal management remains unclear. Smoking is the main risk factor and smoking cessation must be systematically advised. If simple surveillance is acceptable for small PSP and/or paucisymptomatic patient with PSP, exsufflation or hospitalization with chest tube drainage remains the standard treatment in other situations. Ambulatory management is possible and could become the next standard of care. © 2015, Société de réanimation de langue française (SRLF) and Springer-Verlag France
Reanimation

hal-01326967
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01326967
DOI : 10.1007/s13546-015-1156-1

Éditeur(s) : HAL CCSD Walter de Gruyter
Résumé :  
A method for measuring shrinkage resulting from drying in the three anisotropic directions is developed and tested. Measurements are performed on sawn discs, a technique which simplifies preparation and enables large numbers of measurements. Shrinkage values can be represented as a map of the disc surface. The results indicate that comparisons between shrinkage distribution and tension wood distribution on the discs show a clear relationship and can be measured with relatively high accuracy in reference to the "shrinkage map". In the long term, this method could be useful in the timber industry as a means for choosing the direction in which logs are cut depending on their type of wood composition.
Holzforschung

hal-01032055
https://hal.archives-ouvertes.fr/hal-01032055
DOI : 10.1515/HF.2003.100

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
In the mid-afternoon of 15 July 2007, during the Convective and Orographically induced Precipitation Study (COPS), in a very warm and dry environment, an isolated, short-lived, deep convective system developed over the southern Black Forest. Most of the high-resolution, convection-permitting models involved in COPS were unable to capture this event whereas the Meso-NH forecast was quite skilful. To assess the Meso-NH performance further, the model results were carefully checked against the various and numerous COPS observations. In full agreement with clear-air radar observations, model results underlined the triggering role of a low-level convergence line that developed in the lee of the Feldberg. The main departure from the observations was found to be in the low-level moisture fields, which appeared significantly moister in the model than in the observations and also slightly moister than in the other models. Sensitivity studies showed that this departure from the observations was strongly controlled by the initial surface moisture conditions. When the surface moisture was reduced by 20% or replaced by the value derived from a different analysis, the evolution of the planetary boundary layer was more accurately represented while the storm evolution was still correctly captured. These results demonstrate that the quality of the initial forecast cannot be ascribed to the moist bias of the model. It could therefore be hypothesized that the key parameters for a satisfactory forecast of this event lie more in the ability of the model to reproduce the dynamical forcing accurately than in the characteristics of the air-mass instability.
ISSN: 0035-9009

hal-00554400
https://hal.archives-ouvertes.fr/hal-00554400
DOI : 10.1002/qj.710

Éditeur(s) : HAL CCSD University of Arizona
Résumé : International audience
Taiwan is a young and seismically active mountain belt, where a series of strong earthquakes (M>7) have occurred over the past hundred years. Identifying historical earthquakes around Taiwan is a key to better constrain the geodynamic of this active region. Sedimentological and geochemical analyses of surface sediments from one station offshore east Taiwan revealed the presence of coarse-grained layers interpreted as turbidites. The age of these layers have been determined by 210Pb, 137Cs, and 241Am chronology. Dating of the three most recent turbidites provides ages of AD 2001±3, AD 1950±5, and AD 1928±10. The results show striking temporal correspondence of turbidite layers to large (M≥6.8) earthquakes recorded in the region since the 20th century. The chronologies of sediment layers lead us to believe that turbidites resulted from the 2003 Taitung earthquake (M 6.8), the 1951 Chengkong earthquake (M 7.1), and the 1935 Lutao earthquake (M 7.0), respectively. Such a good correlation between turbidites and high-magnitude (M≥6.8) historical and instrumental seismic events suggests that turbidite paleoseismology constitutes a valuable tool for earthquake assessment in the eastern Taiwan margin. Moreover, the modern reservoir radiocarbon age and the regional marine reservoir correction (ΔR) of the Kuroshio Current off Taiwan were estimated by comparing accelerator mass spectrometry (AMS) 14C ages with ages derived from corrected 210Pb profiles and historical accounts of identifiable seismic events. Such a determination is important to calibrate the 14C ages of marine materials for accurate comparison of marine and continental geological records. Our calculated mean ΔR value of 232±54 14C yr (n=2) is higher than its modern value of 86±40 14C yr. This high value can be explained by the presence of local upwelling cells and turbulence in the Kuroshio Current, north of Green Island. These upwelling cells bring 14C-depleted water to the surface, resulting in an increase of the modern ΔR value in this portion of the Kuroshio Current.
ISSN: 0033-8222

hal-01306986
https://hal.archives-ouvertes.fr/hal-01306986
DOI : 10.1017/RDC.2015.3

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
We present a set of single-well injection withdrawal tracer tests in a paleoreef porous reservoir displaying important small-scale heterogeneity. An improved dual-packer probe was designed to perform dirac-like tracer injection and accurate downhole automatic measurements of the tracer concentration during the recovery phase. By flushing the tracer, at constant flow rate, for increasing time duration, we can probe distinctly different reservoir volumes and test the multiscale predictability of the (non-Fickian) dispersion models. First we describe the characteristics, from microscale to meter scale, of the reservoir rock. Second, the specificity of the tracer test setup and the results obtained using two different tracers and measurement methods (salinity-conductivity and fluorescent dye­optical measurement, respectively) are presented. All the tracer tests display strongly tailed breakthrough curves (BTC) consistent with diffusion in immobile regions. Conductivity results, measured over 3 orders of magnitude only, could have been easily interpreted by the conventional mobile-immobile (MIM) diffusive mass transfer model of asymptotic log-log slope of 2. However, the fluorescent dye sensor, which allows exploring much lower concentration values, shows that a change in the log-log slope occurs at larger time with an asymptotic value of 1.5, corresponding to the double-porosity model. These results suggest that the conventional, one-slope MIM transfer rate model is too simplistic to account for the real multiscale heterogeneity of the diffusion-dominant fraction of the reservoir.
ISSN: 0043-1397

insu-00373695
https://hal-insu.archives-ouvertes.fr/insu-00373695
https://hal-insu.archives-ouvertes.fr/insu-00373695/document
https://hal-insu.archives-ouvertes.fr/insu-00373695/file/Gouze_et_al-2008-Water_Resources_Research.pdf
DOI : 10.1029/2007WR006278

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
In spite of several studies on factors affecting nitrogen (N) export in water, the spatiotemporal variability of N export is rarely addressed. This review aims at discussing the different factors involved in N export in water and the intra-annual variability of N occurrences in rivers at a watershed scale. From the analysis of the existing works some recommendations on future research work are proposed regarding (i) other N forms than nitrate being systematically considered for routine analysis or experimental studies (at least Kjheldal nitrogen), (ii) hydrologists and biogeochemists working together to better understanding of N dynamics according to water pathways, especially during “situations at risk,” (iii) water quality monitoring being reinforced both spatially and temporally, especially thanks to high frequency instrumentation, and (iv) accurate data on watersheds needed to give better explanations of N variations. We argue that a better understanding of spatiotemporal variability could greatly enhance the remediation of N export impacts, which is crucial to anticipate the impacts of global changes
ISSN: 1064-3389

hal-01195736
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01195736
DOI : 10.1080/10643389.2015.1010432

Éditeur(s) : Ieee-inst Electrical Electronics Engineers Inc
Résumé : The synthetic aperture radar (SAR) Doppler centroid has been used to estimate the scatter line-of-sight radar velocity. In weak to moderate ocean surface current environment, the SAR Doppler centroid is dominated by the directionality and strength of wave-induced ocean surface displacements. In this paper, we show how this sea state signature can be used to improve surface wind retrieval from SAR. Doppler shifts of C-band radar return signals from the ocean are thoroughly investigated by colocating wind measurements from the ASCAT scatterometer with Doppler centroid anomalies retrieved from Envisat ASAR. An empirical geophysical model function (CDOP) is derived, predicting Doppler shifts at both VV and HH polarization as function of wind speed, radar incidence angle, and wind direction with respect to radar look direction. This function is used into a Bayesian inversion scheme in combination with wind from a priori forecast model and the normalized radar cross section (NRCS). The benefit of Doppler for SAR wind retrieval is shown in complex meteorological situations such as atmospheric fronts or low pressure systems. Using in situ information, validation reveals that this method helps to improve the wind direction retrieval. Uncertainty of the calibration of Doppler shift from Envisat ASAR hampers the inversion scheme in cases where NRCS and model wind are accurate and in close agreement. The method is however very promising with respect of future SAR missions, in particular Sentinel-1, where the Doppler centroid anomaly will be more robustly retrieved.
Ieee Transactions On Geoscience And Remote Sensing (0196-2892) (Ieee-inst Electrical Electronics Engineers Inc), 2012-07 , Vol. 50 , N. 7 , P. 2901-2909

Droits : 2012 IEEE
http://archimer.ifremer.fr/doc/00088/19896/17554.pdf
DOI:10.1109/TGRS.2011.2174998
http://archimer.ifremer.fr/doc/00088/19896/

Éditeur(s) : Université de Bretagne Occidentale
Résumé : The magmatology of Mount Pelée is characterized by the competition between two major petrogenetic processes : Iractional crystallization and magma mixing. The important volcanic hazards associated with this volcano make the interest of the study: the existence of accurate datas about its geology and the chronology of its eruptions is favorable to a magmatologic study. The aim of this work, carried out within the framework of the PIRPSEV, is to determine the relative importance of the petrogenetic processes involved during the volnano history and then to conclude about the functioning of the underlying magma chambers. It is found upon the petrographical, mineralogical and geochemical characteristics of the ejecta of Mount Pelée. NOT CONTROLLED OCR
La magmatologie de la Montagne Pelée est caractérisée par la compétition entre deux processus pétrogénétiques : la cristallisation fractionnée et le mélange magmatique. L'intérêt de l'étude de cet édifice réside dans l'importance considérable des risques volcaniques qui lui sont associés; l'existence de données très précises sur sa géologie et sur la chronologie de ses éruptions offre un cadre favorable à une étude magmatologique. Le présent travail, réalisé dans le cadre du PIRPSEV, vise à déterminer, à partir de l'ensemble des caractéristiques pétrographiques, minéralogiques et géochimiques des matériaux volcaniques de la Montagne Pelée, l'importance relative des processus pétrogénétiques impliqués au cours de l'histoire de ce volcan, et d'en tirer des conclusions sur le fonctionnement des réservoirs magmatiques sous-jacents. OCR NON CONTRÔLE

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1986/these-3752.PDF
http://archimer.ifremer.fr/doc/00000/3752/

Éditeur(s) : Elsevier Sci Ltd
Résumé : The aim of this study is to establish a baseline for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) lifetime prediction in a marine environment, by means of mechanical and physico-chemical characterization of specimens immersed in continuously renewed and filtered natural seawater in the laboratory at different temperatures (4, 25 and 40°C). Samples were also aged at sea in Lorient harbour in order to compare laboratory and natural degradation mechanisms and kinetics. Due to its morphology, hydrolysis of PHBV in natural seawater is quite slow, and samples were observed to undergo preferentially an enzymatic surface degradation. Increasing the aging temperature in the laboratory promotes the water uptake and causes hydrolysis. As two degradation mechanisms occur in parallel, the choice of test conditions is critical, and the lifetime of PHBV in a marine environment is difficult to predict accurately.
Polymer Degradation And Stability (0141-3910) (Elsevier Sci Ltd), 2014-07 , Vol. 105 , P. 237-247

Droits : 2014 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00188/29972/28425.pdf
DOI:10.1016/j.polymdegradstab.2014.04.026
http://archimer.ifremer.fr/doc/00188/29972/

Éditeur(s) : HAL CCSD Wiley
Résumé : 1. Functional traits provide insight into a variety of ecological questions, yet the optimal sampling method to estimate the community-level distribution of plant functional trait values remains a subject of debate, especially in species-rich forests. 2. We present a simulation analysis of the trait distribution of a set of nine completely sampled permanent plots in the lowland rain forests of French Guiana. 3. Increased sampling intensity consistently improved accuracy in estimating community-weighted means and variances of functional trait values, whereas there was substantial variation among functional traits and minor differences among sampling strategies. 4. Thus, investment in intensified sampling yields a greater improvement in the accuracy of estimation than does an equivalent investment in sampling design complication. 5. Notably, 'taxon-free' strategies frequently had greater accuracy than did abundance-based strategies, which had the additional cost of requiring botanical surveys. 6. We conclude that there is no substitute for extensive field sampling to accurately characterize the distribution of functional trait values in species-rich forests.
ISSN: 0269-8463

hal-01536541
https://hal.archives-ouvertes.fr/hal-01536541
PRODINRA : 343202
DOI : 10.1111/1365-2435.12433

Éditeur(s) : HAL CCSD
Résumé : For a decade, distance-based methods have been widely employed and constantly improved in the field of spatial economics. These methods are a very useful tool for accurately evaluating the spatial distribution of plants or retail stores, for example (Duranton and Overman, 2008). In this paper, we introduce a new distance-based statistical measure for evaluating the spatial concentration of economic activities. To our knowledge, the m function is the first relative density function to be proposed in the economics literature. This tool supplements the typology of distance-based methods recently drawn up by Marcon and Puech (2012). By considering several theoretical and empirical examples, we show the advantages and the limits of the m function for detecting spatial structures in economics.
https://hal.archives-ouvertes.fr/hal-01082178

hal-01082178
https://hal.archives-ouvertes.fr/hal-01082178
https://hal.archives-ouvertes.fr/hal-01082178v3/document
https://hal.archives-ouvertes.fr/hal-01082178/file/LANG-%20MARCON-PUECH%20-%20m%20-%20HAL%2001082178v3.pdf

Éditeur(s) : EDP Sciences
Résumé : The present paper aims at identifying and assessing indicators of the effects of Marine Protected Areas (MPAs) in coral reef regions, based on a bibliography review in ecology, economics and social sciences. First the various effects Studied within each of these domains and the variables used to measure them were censused. Potential ecological indicators were assessed through their link with the question used (here termed "relevance") and their "effectiveness" which encompasses the issues of precision, accuracy and statistical power. Relevance and effectiveness were respectively measured by the frequency of use of each indicator and the proportion of significant results in the reviewed articles. For social and economic effects, the approach was not possible due to the low number of references: we thus discussed the issue of finding appropriate indicators for those fields. Results indicate: 1- the unbalance in literature between disciplines: 2- the need for protocols and methodologies which include controls in order to assess MPA effects: 3- an important proportion of ecological indicators with low effectiveness: 4- the large number of ecological effects still not studied or not demonstrated at present.
Cet article vise à identifier des indicateurs de l'effet des aires marines protégées (AMP) en milieu corallien, sur la base d'une synthèse bibliographique dans les domaines écologiques, économiques et sociaux, et principalement en milieu corallien. Nous recensons d'abord les différents effets attendus des AMP pour chacun des domaines, et les variables retenues pour les étudier. Les indicateurs écologiques potentiels sont évalués au travers de leur lien avec l'effet étudié (ici appelé "pertinence") et de leur "efficacité" qui regroupe les notions de précision, justesse et puissance statistique. Pertinence et efficacité sont respectivement mesurées par la fréquence d'utilisation et la proportion de résultats significatifs trouvés dans les articles recensés. Pour les aspects économiques et sociaux, le faible nombre de références ne permet pas une approche comparable à celle utilisée pour les indicateurs écologiques, et nous discutons donc de la question de l'identification d'indicateurs, et suggérons quelques pistes de recherche. Les principales conclusions de ce travail sont: i) le décalage entre les nombres de publications entre disciplines; ii) la nécessité de protocoles et méthodologies incluant des situations de contrôle pour évaluer les effets des MPA; iii) la faible efficacité de nombreux indicateurs écologiques; et iv) le nombre élevé d'effets peu ou pas étudiés ou démontrés à l'heure actuelle.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2005 , Vol. 18 , N. 1 , P. 15-33

Droits : EDP Sciences, IFREMER, IRD 2005
http://archimer.ifremer.fr/doc/2005/publication-409.pdf
DOI:10.1051/alr:2005011
http://archimer.ifremer.fr/doc/00000/409/

Éditeur(s) : Amer Meteorological Soc
Résumé : Salinity measurements from 119 surface drifters in 2007-12 were assessed; 80% [Surface Velocity Program with a barometer with a salinity sensor (SVP-BS)] and 75% [SVP with salinity (SVP-S)] of the salinity data were found to be usable, after editing out some spikes. Sudden salinity jumps are found in drifter salinity records that are not always associated with temperature jumps, in particular in the wet tropics. A method is proposed to decide whether and how to correct those jumps, and the uncertainty in the correction applied. Northeast of South America, in a region influenced by the Amazon plume and fresh coastal water, drifter salinity is very variable, but a comparison with data from the Soil Moisture and Ocean Salinity satellite suggests that this variability is usually reasonable. The drifter salinity accuracy is then explored based on comparisons with data from Argo floats and from thermosalinographs (TSGs) of ships of opportunity. SVP-S/SVP-BS drifter records do not usually present significant biases within the first 6 months, but afterward biases sometimes need to be corrected (altogether, 16% of the SVP-BS records). Biases start earlier after 3 months for drifters not protected by antifouling paint. For the few drifters for which large corrections were applied to portions of the record, the accuracy cannot be proven to be better than 0.1 psu, and it cannot be proven to be better than 0.5 psu for data in the largest variability area off northeast South America. Elsewhere, after excluding portions of the records with suspicious salinity jumps or when large corrections were applied, the comparisons rule out average biases in individual drifter salinity record larger than 0.02 psu (midlatitudes) and 0.05 psu (tropics).
Journal Of Atmospheric And Oceanic Technology (0739-0572) (Amer Meteorological Soc), 2014-04 , Vol. 31 , N. 4 , P. 967-983

Droits : 2014 American Meteorological Society
http://archimer.ifremer.fr/doc/00190/30095/28748.pdf
DOI:10.1175/JTECH-D-13-00158.1
http://archimer.ifremer.fr/doc/00190/30095/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The full numerical simulation of turbulent flows in the context of industrial applications remains a very challenging problem. One of the difficulties is the presence of a large number of interacting scales of different orders of magnitude, ranging from the macroscopic scale to the Kolmogorov dissipation scale. In order to better understand and simulate these interactions, new algorithms of incremental type have recently been introduced, stemming from the theory of infinite-dimensional dynamical systems (see, e.g., the algorithms of Foias, Jolly et al. (1988), Foias, Manley and Temam (1988), Laminie et al. (1993, 1994), Marion and Temam (1989, 1990), and Temam (1990)). These algorithms are based on decompositions of the unknown functions into a large- and a small-scale component, one of the underlying ideas being to approximate the corresponding attractor. In the context of finite element methods, the decomposition of a solution into small- and large-scale components appears when we consider hierarchical bases (Yserentant, 1986; Zienkiewicz et al., 1982). In the present article we derive several estimates of the size of the structures for the linear and nonlinear terms which correspond to interactions of different hierarchical components of the velocity field, and also their time variation. The one-step time variation of these terms can be smaller than the expected accuracy of the computation. Using this remark, we implement an adaptive spatial and temporal multilevel algorithm which treats differently the small- and large-scale components of the flow. We derive several a priori estimates in order to study the perturbation introduced into the approximated equations. All the interaction terms between small- and large-scale structures are frozen during several time steps. Finally, we implement the multilevel method in order to simulate a bidimensional flow described by the Burgers equations. We perform a parametric study of the procedure and its efficiency. The gain in CPU time is significant and the trajectories computed by our multi-scale method remain close to the trajectories obtained with the classical Galerkin method.
ISSN: 0168-9274

hal-00730710
https://hal.archives-ouvertes.fr/hal-00730710

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
In this paper we investigate finite-frequency effects in crustal tomography. We developed an inversion procedure based on an exact numerical computation of the sensitivity kernels. In this approach we compute the 3D travel-time sensitivity kernels by using (1) graph theory and an additional bending to estimate accurately both rays and travel-times between source/receiver and diffraction points and (2) paraxial ray theory to estimate the amplitude along theses rays. We invert both the velocity and the hypocentre parameters, using these so-called banana-doughnut kernels and the LSQR iterative solver. We compare the ray-theoretical and the finite-frequency tomography to image the intermediate structures beneath the Gulf of Corinth (Greece), which has long been recognized as the most active continental rifting zone in the Mediterranean region. Our dataset consists of 451 local events with 9233 P- firstarrival times recorded in the western part of the Gulf (Aigion area) in the framework of the 3F-Corinth European project. Previous tomographic images showed a complex velocity crustal model and a low-dip surface that may accommodate the deformation. Accurate velocity models will help to better constrain the rifting process, which is still a subject of debate. The main results of this study show that finite-frequency tomography improves crustal tomographic images by providing better resolved images of the 3D complicated velocity structure. Because the kernels spread the information over a volume, finite-frequency tomography results in a sharpening of layer boundaries as we observed for the shallower part of the crust (down to 5 km depth) beneath the Gulf of Corinth.
ISSN: 0016-8025

insu-00354702
https://hal-insu.archives-ouvertes.fr/insu-00354702
DOI : 10.1111/j.1365-2478.2007.00683.x