Search

In the context of the diachronic analysis of rates, indices or ratios, the literature regularly proposes to calculate the average via a geometric formula. This article aims to show that this rule is not acceptable. The reflection is governed by the following basic principle: the average annual growth rate corresponds to the value of the rate which, applied during the different years under observation, leads to the same growth as that actually observed between the beginning and end of the observation period. Its application to the three population growth hypotheses commonly used in demography demonstrates that the average growth rate is never obtained via a geometric formula of the average. Moreover, the standard application of the basic principle gives rise to a formula for the average rate under the assumption of linear growth which contradicts the formula usually followed and which must therefore be abandoned. Résumé Dans le cadre de l’analyse diachronique de taux, d’indices ou de rapports, la littérature propose régulièrement de calculer la moyenne via une formule géométrique. Cet article vise à montrer que cette règle n’est pas acceptable. La réflexion est régie par le principe de base suivant : le taux de croissance annuel moyen correspond à la valeur du taux qui, appliquée durant les différentes années sous observation, conduit à la même croissance que celle effectivement observée entre le début et la fin de la période d’observation. Son application aux trois hypothèses de croissance de la population utilisées couramment en démographie démontre que le taux de croissance moyen n’est jamais obtenu via une formule géométrique de la moyenne. Par ailleurs, l’application du principe de base fait émerger une formule du taux moyen sous hypothèse de croissance linéaire en contradiction avec la formule habituellement suivie et qui doit donc être abandonnée.

The safeguard clause is a mechanism for the collective regulation of drug-related expenditure. It consists in the payment to the health insurance of a contribution from the pharmaceutical industries of a part of the overspending between the growth of the laboratories' turnover and a rate of progression defined during the elaboration of the Social Security Financing Law. As a complementary mechanism of drug regulation, since 2015, almost annual reforms are observed, and a significant contribution is due by the pharmaceutical industries. The objective of this thesis is to understand the evolution of this mechanism and to identify its adaptation to the current context, marked by the emergence of innovations and a deficit of the health insurance accounts of 30.4 billion euros in 2020. An analysis was carried out in order to understand the evolution of this mechanism according to the different parameters that constitute it in relation to the evolution of the sector. The first part is devoted to the presentation of the health system and the introduction of the safeguard clause in the balance of drug expenditure. The second part is a retrospective analysis of the safeguard clause from its creation in 1999 to 2021. Finally, the third part looks at the different points of view of the actors contributing to the regulation of health products in order to gather their perception of the system and the pitfalls they identify. Interviews were conducted at the LEEM, the CEPS, the DSS, the DGE and within laboratories in order to identify avenues of reflection aimed at making changes that would reconcile innovation and sustainability.; La clause de sauvegarde est un mécanisme de régulation collectif des dépenses liées aux médicaments. Elle consiste au versement à l’assurance maladie d’une contribution des industries pharmaceutiques d’une partie du dépassement des dépenses entre la croissance du chiffre d’affaires des laboratoires et un taux de progression défini lors de l’élaboration de la Loi de Financement de la sécurité sociale. Mécanisme « chapeau » de la régulation des médicaments, depuis 2015, des réformes quasi-annuelles sont observées et une contribution significative est due par les industries pharmaceutiques. L’objectif de cette thèse est de comprendre l’évolution de ce mécanisme et d’identifier son adaptation au contexte actuel, marqué par l’émergence d’innovations et un déficit des comptes de l’assurance maladie de 30,4 Milliards d’euros en 2020. Une analyse a été réalisée afin de comprendre l’évolution de ce dispositif selon les différents paramètres qui la constitue en relation avec l’évolution du secteur. La première partie est consacrée à la présentation du système de santé et l’introduction de la clause de sauvegarde dans l’équilibre de la dépense des médicaments. La seconde partie est une analyse rétrospective de la clause de sauvegarde de sa création en 1999 à 2021. Enfin, la troisième partie s’intéresse aux différents points de vue des acteurs contribuant à la régulation des produits de santé afin de recueillir leur perception du système et les écueils qu’ils identifient. Des entretiens ont été menés au LEEM, au CEPS, à la DSS, à la DGE et au sein des laboratoires afin d’aboutir à des pistes de réflexion visant à opérer des changements permettant de concilier les innovations et la soutenabilité.

L’objet de cet article consiste à analyser l’impact du sentiment de l’investisseur sur le rendement des actions et de montrer le rôle des variables macroéconomiques (taux d’inflation, taux de chômage et taux de croissance) dans l’explication de ce rendement. L’échantillon est constitué d’observations annuelles de cinquante huit sociétés cotées à la bourse des valeurs de Casablanca, observées sur la période qui s’étale de 2010 jusqu’à l’an 2019. Les résultats obtenus, au moyen d’une analyse corrélationnelle et d’une régression linéaire multiple, font ressortir l’existence des relations positives et importantes entre le rendement et ses variables explicatives sauf pour le taux d’inflation et le taux de croissance du pays, elles ont des relations négatives et faibles avec le return. Les variables retenues sont statistiquement significatives pour expliquer la variation longitudinale du rendement d’une action cotée sur le marché boursier marocain., Moroccan Journal of Entrepreneurship, Innovation and Management, Vol 6, No 1 (2021)

Background Drought tolerance is a major challenge in breeding rice for unfavorable environments. In this study, we used a panel of 180 Vietnamese rice landraces genotyped with 21,623 single-nucleotide polymorphism markers to perform a genome-wide association study (GWAS) for different drought response and recovery traits during the vegetative stage. These landraces originate from different geographical locations and are adapted to different agrosystems characterized by contrasted water regimes. Vietnamese landraces are often underrepresented in international panels used for GWAS, but they can contain original genetic determinants related to drought resistance. Results The panel of 180 rice varieties was phenotyped under greenhouse conditions for several drought-related traits in an experimental design with 3 replicates. Plants were grown in pots for 4 weeks and drought-stressed by stopping irrigation for an additional 4 weeks. Drought sensitivity scores and leaf relative water content were measured throughout the drought stress. The recovery capacity was measured 2 weeks after plant rewatering. Several QTLs associated with these drought tolerance traits were identified by GWAS using a mixed model with control of structure and kinship. The number of detected QTLs consisted of 14 for leaf relative water content, 9 for slope of relative water content, 12 for drought sensitivity score, 3 for recovery ability and 1 for relative crop growth rate. This set of 39 QTLs actually corresponded to a total of 17 different QTLs because 9 were simultaneously associated with two or more traits, which indicates that these common loci may have pleiotropic effects on drought-related traits. No QTL was found in association with the same traits in both the indica and japonica subpanels. The possible candidate genes underlying the quantitative trait loci are reviewed. Conclusions Some of the identified QTLs contain promising candidate genes with a function related to drought tolerance by osmotic stress adjustment. Electronic supplementary material The online version of this article (10.1186/s12284-018-0258-6) contains supplementary material, which is available to authorized users.

International audience; The Nile tilapia (Oreochromis niloticus) was introduced in Southeast Asia, such as in Thailand, in the mid-1960s for aquaculture purposes (Pullin et al., 1997; De Silva et al., 2004). The species was later promoted for aquaculture development in the early 1990s in Lao PDR (Garaway et al., 2000). In Lao People’s Democratic Republic (PDR), like in other countries, this exotic species is well established due to its self-reproduction (De Silva et al., 2004; CABI, 2018) facilitated by its particular life history traits and plasticity (Ishikawa et al., 2013). The species was then suspected to be introduced in the seventies in Laos and subsequently in the Nam Theun watershed where the NT2 Reservoir was impounded in 2008. Population parameters of this alien fish were investigated using the FiSAT II software with the most popular methods of bioparameters assessment to check their interchangeability within a same stock and the same year 2016. The length-at-age data analysis (using otoliths analysis, N = 258) gave slightly different results with the length frequency distribution analysis of fish landings (11 820 individuals). Furthermore, experimental fishing data provided irrelevant parameters due to insufficient representativeness of the sample size. The growth parameter K was estimated to be 0.23 year−1, with asymptotic length L∞ = 52.5 cm based on the length frequency distribution analysis with the fish landing data. According to these landing data, the total, natural and fishing mortality were Z = 1.41 year−1, M = 0.30 year−1 and F = 1.11 year−1. The exploitation rate E = 0.79 is over the Emax = 0.594 obtained by relative yield and biomass per recruit. This estimated stock of 165 tons (more than 700 000 tilapias) was characterized by high mortality (no population growth). These results showed that the population is overfished with too many juveniles caught (L50 = 210.4 mm; 50% mature stages at 295 mm). To maximize the yield per recruit, increase the biomass and sustain this fishery, enlarging the gillnet mesh size of the gill-net is recommended. This example highlights the variability of the parameters calculated from different methods and thus weaken worldwide and even inter-site comparisons. Despite this issue, the Growth Performances Indices (φ′) gathered into the literature can serve as baseline and confirmed the wide phenotypic plasticity of the species due to environmental factors. Analyses revealed difference between fast growing domesticated fish rose for aquaculture with φ′ higher to the tilapia growing in natural and challenging environments.; Le Tilapia du Nil (Oreochromis niloticus) a été introduit en Asie du sud-ouest, notamment en Thaïlande, dans le milieu des années 1960, à des fins d’aquaculture. Ce n’est que dans les années 1990 que cette espèce a été introduite au Laos pour ce même objectif. Cette espèce exotique, de par sa capacité de reproduction naturelle induite par ses traits d’histoire de vie et sa plasticité phénotypique, est bien établie au Laos, ainsi que dans d’autres pays asiatiques. Cette espèce présente dans le bassin versant de Nam Theun aurait ainsi colonisé le réservoir de Nam Theun 2 (NT2) lors de sa mise en eau en 2008, avec également des actions sporadiques d’empoissonnements. Les paramètres de la population du réservoir de NT2 ont été étudiés en recourant à FiSAT II avec les méthodes d’évaluation des bio-paramètres les plus populaires pour vérifier leur interchangeabilité dans un même stock et pour une même année (2016). L’analyse de la relation taille-âge, via l’analyse de 258 otolithes, a donné des résultats légèrement différents de l’analyse des fréquences de tailles issues des débarquements réalisées sur 11 820 individus. Les données issues des pêches expérimentales ont quant-à-elles fournis des résultats non pertinents de par le faible effectif des échantillons. La croissance (k) a été estimée à 0,23 cm an−1 avec une longueur asymptotique (L∞) de 52,5 cm. Selon les données de débarquements la mortalité totale, naturelle et par pêche étaient respectivement de 1,41, 0,30 et 1,11 an−1. Le taux d’exploitation (0,79) était supérieur au taux d’exploitation maximal (0,594) obtenu par le rendement relatif et la biomasse par recrue. Le stock estimé de 165 tonnes (plus de 700 000 individus) était caractérisé par une mortalité élevée. Ces résultats ont montré que la population était surexploitée et que de nombreux juvéniles étaient capturés (L50 = 210,4 mm; 50% mature à 295 mm). Pour maximiser le rendement par recrue, augmenter la biomasse, et soutenir la pêche, il est recommandé d’augmenter la taille des mailles des filets de pêche. Cet exemple met en évidence la variabilité des paramètres calculés à partir de différentes méthodes ce qui sous-entend que les comparaisons avec les autres populations dans le monde, mais également inter-sites sont difficiles. Toutefois les indices de performance de croissance (φ′) relevés dans la littérature peuvent servir de référentiel et confirmer la grande plasticité phénotypique de cette espèce selon les facteurs environnementaux. Les analyses ont révélé que les populations aquacoles présentaient une croissance plus rapide que celle des populations vivant dans les environnements naturels contraignants.

International audience; The Nile tilapia (Oreochromis niloticus) was introduced in Southeast Asia, such as in Thailand, in the mid-1960s for aquaculture purposes (Pullin et al., 1997; De Silva et al., 2004). The species was later promoted for aquaculture development in the early 1990s in Lao PDR (Garaway et al., 2000). In Lao People’s Democratic Republic (PDR), like in other countries, this exotic species is well established due to its self-reproduction (De Silva et al., 2004; CABI, 2018) facilitated by its particular life history traits and plasticity (Ishikawa et al., 2013). The species was then suspected to be introduced in the seventies in Laos and subsequently in the Nam Theun watershed where the NT2 Reservoir was impounded in 2008. Population parameters of this alien fish were investigated using the FiSAT II software with the most popular methods of bioparameters assessment to check their interchangeability within a same stock and the same year 2016. The length-at-age data analysis (using otoliths analysis, N = 258) gave slightly different results with the length frequency distribution analysis of fish landings (11 820 individuals). Furthermore, experimental fishing data provided irrelevant parameters due to insufficient representativeness of the sample size. The growth parameter K was estimated to be 0.23 year−1, with asymptotic length L∞ = 52.5 cm based on the length frequency distribution analysis with the fish landing data. According to these landing data, the total, natural and fishing mortality were Z = 1.41 year−1, M = 0.30 year−1 and F = 1.11 year−1. The exploitation rate E = 0.79 is over the Emax = 0.594 obtained by relative yield and biomass per recruit. This estimated stock of 165 tons (more than 700 000 tilapias) was characterized by high mortality (no population growth). These results showed that the population is overfished with too many juveniles caught (L50 = 210.4 mm; 50% mature stages at 295 mm). To maximize the yield per recruit, increase the biomass and sustain this fishery, enlarging the gillnet mesh size of the gill-net is recommended. This example highlights the variability of the parameters calculated from different methods and thus weaken worldwide and even inter-site comparisons. Despite this issue, the Growth Performances Indices (φ′) gathered into the literature can serve as baseline and confirmed the wide phenotypic plasticity of the species due to environmental factors. Analyses revealed difference between fast growing domesticated fish rose for aquaculture with φ′ higher to the tilapia growing in natural and challenging environments.; Le Tilapia du Nil (Oreochromis niloticus) a été introduit en Asie du sud-ouest, notamment en Thaïlande, dans le milieu des années 1960, à des fins d’aquaculture. Ce n’est que dans les années 1990 que cette espèce a été introduite au Laos pour ce même objectif. Cette espèce exotique, de par sa capacité de reproduction naturelle induite par ses traits d’histoire de vie et sa plasticité phénotypique, est bien établie au Laos, ainsi que dans d’autres pays asiatiques. Cette espèce présente dans le bassin versant de Nam Theun aurait ainsi colonisé le réservoir de Nam Theun 2 (NT2) lors de sa mise en eau en 2008, avec également des actions sporadiques d’empoissonnements. Les paramètres de la population du réservoir de NT2 ont été étudiés en recourant à FiSAT II avec les méthodes d’évaluation des bio-paramètres les plus populaires pour vérifier leur interchangeabilité dans un même stock et pour une même année (2016). L’analyse de la relation taille-âge, via l’analyse de 258 otolithes, a donné des résultats légèrement différents de l’analyse des fréquences de tailles issues des débarquements réalisées sur 11 820 individus. Les données issues des pêches expérimentales ont quant-à-elles fournis des résultats non pertinents de par le faible effectif des échantillons. La croissance (k) a été estimée à 0,23 cm an−1 avec une longueur asymptotique (L∞) de 52,5 cm. Selon les données de débarquements la mortalité totale, naturelle et par pêche étaient respectivement de 1,41, 0,30 et 1,11 an−1. Le taux d’exploitation (0,79) était supérieur au taux d’exploitation maximal (0,594) obtenu par le rendement relatif et la biomasse par recrue. Le stock estimé de 165 tonnes (plus de 700 000 individus) était caractérisé par une mortalité élevée. Ces résultats ont montré que la population était surexploitée et que de nombreux juvéniles étaient capturés (L50 = 210,4 mm; 50% mature à 295 mm). Pour maximiser le rendement par recrue, augmenter la biomasse, et soutenir la pêche, il est recommandé d’augmenter la taille des mailles des filets de pêche. Cet exemple met en évidence la variabilité des paramètres calculés à partir de différentes méthodes ce qui sous-entend que les comparaisons avec les autres populations dans le monde, mais également inter-sites sont difficiles. Toutefois les indices de performance de croissance (φ′) relevés dans la littérature peuvent servir de référentiel et confirmer la grande plasticité phénotypique de cette espèce selon les facteurs environnementaux. Les analyses ont révélé que les populations aquacoles présentaient une croissance plus rapide que celle des populations vivant dans les environnements naturels contraignants.

International audience; Light intensity drives whole-plant carbon gain, with consequences for biomass production and plant community dynamics in forest systems. Recent studies suggest that soil microbial communities may mediate the impacts of resource availability on plant performance, yet little is known about the net effect of conspecific soil microorganisms for tree seedling light responses. Here we examined the interactive effects of light availability and presence of conspecific soil microorganisms on tree seedling growth, morphology and nutrient content for two congeneric tropical tree species. The two Bauhinia tree species with contrasting shade tolerance were grown in sterilized or unsterilized soil medium, under either high (50%) or low (10%) light conditions in a greenhouse experiment. Plant light responses and soil feedback effects were determined after 12 weeks. Results showed that the light-demanding tree species was generally more responsive to both light and soil microbes compared with its shade-tolerant congener. Presence of soil microbes enhanced plant growth and biomass responses to increased light availability for the light-demanding species alone, driven by positive soil feedback effects in high light. Six plant traits (leaf mass fraction, stem mass fraction, specific stem length, leaf phosphorus concentration, leaf nitrogen: phosphorus ratio and root nitrogen: phosphorus ratio) showed significant interactive effects between light and soil treatment. Observed changes to leaf biomass allocation in response to light in the presence of conspecific soil microorganisms were consistent with optimality theory and adjustments to maximize resource acquisition under different light conditions. In addition, presence of soil microbes decreased the average plasticity of plant nutrient content and stoichiometry in response to light for the light-demanding Bauhinia species. Together these results highlight the importance of conspecific soil microbes for plant-light relations, with implications for plant-plant interactions and species coexistence.

Motions of galaxies in the universe are due to the rivalry between the expansion of the universe and gravitation. This tug-of-war impacts the formation and the growth of large scale structures of the universe. Thus, depending on the identity of the winner of this duel, the universe is more or less compact. Within this context, this PhD thesis is divided into three parts, spanning from HI observations to the estimate of the growth of rate of large scale structures of the universe and the compactness of the local universe.The Cosmicflows collaboration assembles catalogues of galaxy distances. Up to now, three catalogues have been published, the last one being Cosmicflows-3. This thesis presents and analyses observational data obtained from HI observations. These new data will be used to construct the new compilation of distances Cosmicflows-4 by the use of the Tully-Fisher relation, in order to correct the lack of data in the Northern celestial hemisphere in the current catalog.From the distance of a galaxy, one can derive the radial part of its peculiar velocity corresponding to the component of its total velocity caused by gravitation. Peculiar velocities allow to probe the matter content of the universe and to extract information on large scale structures of the universe. Two methodologies using peculiar velocities have been developed during this thesis to characterize large scale structures of the local universe.On the one hand, peculiar velocity catalogues can be used to reconstruct tri-dimensional velocity fields. These velocity field allow one to map the structure of the local universe and are used in this thesis to identify gravitational basins and valleys within the local universe by computing streamlines.On the other hand, a method based on the analysis of two-point galaxy peculiar velocity correlations has been developed in order to constrain the growth rate of large scale structures of the local universe from observational data. This method is applied to the Cosmicflows-3 catalogue of observed peculiar velocities; Les mouvements des galaxies dans l'Univers sont causés par le tir à la corde qui a lieu entre l'expansion de l'univers et la gravitation. Cette rivalité a un impact sur la formation et la croissance des grandes structures de l'univers. Par conséquent, l'univers est plus ou moins compact selon le gagnant de ce duel. Dans ce contexte, cette thèse est divisée en trois parties, allant des observations à 21 cm à la mesure du taux de croissance actuel des grandes structures de l'univers et de la compacité de l'univers local.La collaboration Cosmicflows prépare des catalogues de distances de galaxies. Jusqu'à présent, trois catalogues ont été publiés, le dernier étant Cosmicflows-3. Cette thèse présente et analyse les données obtenues à partir d'observations à 21 cm. Ces nouvelles données seront utilisées pour former le prochain catalogue de distances Cosmicflows-4 à l'aide de la relation de Tully-Fisher, afin de corriger le manque de données dans l'hémisphère céleste Nord dans le catalogue actuel.À partir de la distance d'une galaxie, il est possible d'en déduire la partie radial de sa vitesse particulière, correspondant à la composante de sa vitesse totale causée par la gravitation. Les vitesses particulières des galaxies sont des sondes non-baisées de la matière et permettent d'extraire des informations sur les grandes structures de l'univers. Deux méthodologies utilisant les vitesses particulières ont été développées durant cette thèse pour caractériser les grandes structures de l'univers local.D'une part, les catalogues de vitesses particulières peuvent être utilisés pour reconstruire des champs de vitesse tridimensionnels. De tels champs de vitesse permettent de cartographier la structure de l'univers local et sont exploités dans cette thèse, à l'aide des lignes de flux, pour identifier des bassins et vallées gravitationnels dans l'univers local.D'autre part, une méthode basée sur l'analyse des corrélations à deux points des vitesses particulières des galaxies a été développée afin d'exhiber le taux de croissance actuel des grandes structures de l'univers local à partir de données observationnelles. Cette méthodologie est appliquée au catalogue observationnel de vitesses particulières Cosmicflows-3

2. International Conference on Alternative Fuels and Energy (ICAFE) ; Daegu (Corée (Populaire)) - (2017-10-23 - 2017-10-25) / Conférence; Studies of the effects of electromagnetic waves on Saccharomyces cerevisiae emphasize the need to develop instrumented experimental systems ensuring a characterization of the exposition level to enable unambiguous assessment of their potential effects on living organisms. A bioreactor constituted with two separate compartments has been designed. The main element (75% of total volume) supporting all measurement and control systems (temperature, pH, agitation, and aeration) is placed outside the exposure room whereas the secondary element is exposed to irradiation. Measurements of the medium dielectric properties allow the determination of the electromagnetic field at any point inside the irradiated part of the reactor and are consistent with numerical simulations. In these conditions, the growth rate of Saccharomyces cerevisiae and the ethanol yield in aerobic conditions are not significantly modified when submitted to an electromagnetic field of 900 and 2400 MHz with an average exposition of 6.11 V.m−1 and 3.44 V.m−1 respectively.

Motions of galaxies in the universe are due to the rivalry between the expansion of the universe and gravitation. This tug-of-war impacts the formation and the growth of large scale structures of the universe. Thus, depending on the identity of the winner of this duel, the universe is more or less compact. Within this context, this PhD thesis is divided into three parts, spanning from HI observations to the estimate of the growth of rate of large scale structures of the universe and the compactness of the local universe.The Cosmicflows collaboration assembles catalogues of galaxy distances. Up to now, three catalogues have been published, the last one being Cosmicflows-3. This thesis presents and analyses observational data obtained from HI observations. These new data will be used to construct the new compilation of distances Cosmicflows-4 by the use of the Tully-Fisher relation, in order to correct the lack of data in the Northern celestial hemisphere in the current catalog.From the distance of a galaxy, one can derive the radial part of its peculiar velocity corresponding to the component of its total velocity caused by gravitation. Peculiar velocities allow to probe the matter content of the universe and to extract information on large scale structures of the universe. Two methodologies using peculiar velocities have been developed during this thesis to characterize large scale structures of the local universe.On the one hand, peculiar velocity catalogues can be used to reconstruct tri-dimensional velocity fields. These velocity field allow one to map the structure of the local universe and are used in this thesis to identify gravitational basins and valleys within the local universe by computing streamlines.On the other hand, a method based on the analysis of two-point galaxy peculiar velocity correlations has been developed in order to constrain the growth rate of large scale structures of the local universe from observational data. This method is applied to the Cosmicflows-3 catalogue of observed peculiar velocities, Les mouvements des galaxies dans l'Univers sont causés par le tir à la corde qui a lieu entre l'expansion de l'univers et la gravitation. Cette rivalité a un impact sur la formation et la croissance des grandes structures de l'univers. Par conséquent, l'univers est plus ou moins compact selon le gagnant de ce duel. Dans ce contexte, cette thèse est divisée en trois parties, allant des observations à 21 cm à la mesure du taux de croissance actuel des grandes structures de l'univers et de la compacité de l'univers local.La collaboration Cosmicflows prépare des catalogues de distances de galaxies. Jusqu'à présent, trois catalogues ont été publiés, le dernier étant Cosmicflows-3. Cette thèse présente et analyse les données obtenues à partir d'observations à 21 cm. Ces nouvelles données seront utilisées pour former le prochain catalogue de distances Cosmicflows-4 à l'aide de la relation de Tully-Fisher, afin de corriger le manque de données dans l'hémisphère céleste Nord dans le catalogue actuel.À partir de la distance d'une galaxie, il est possible d'en déduire la partie radial de sa vitesse particulière, correspondant à la composante de sa vitesse totale causée par la gravitation. Les vitesses particulières des galaxies sont des sondes non-baisées de la matière et permettent d'extraire des informations sur les grandes structures de l'univers. Deux méthodologies utilisant les vitesses particulières ont été développées durant cette thèse pour caractériser les grandes structures de l'univers local.D'une part, les catalogues de vitesses particulières peuvent être utilisés pour reconstruire des champs de vitesse tridimensionnels. De tels champs de vitesse permettent de cartographier la structure de l'univers local et sont exploités dans cette thèse, à l'aide des lignes de flux, pour identifier des bassins et vallées gravitationnels dans l'univers local.D'autre part, une méthode basée sur l'analyse des corrélations à deux points des vitesses particulières des galaxies a été développée afin d'exhiber le taux de croissance actuel des grandes structures de l'univers local à partir de données observationnelles. Cette méthodologie est appliquée au catalogue observationnel de vitesses particulières Cosmicflows-3

Differences in crop performance between seasons has raised concerns on whether or not contrasting rice varieties should be grown in each season in the tropics. Solving this question requires evaluation if key plant traits subtending grain yield are expressed similarly across seasons. Within each dry season (DS) and wet season (WS), one approach to address the issue was to group 32 high-yielding and contrasted cultivars with respect to crop duration, and to consider the crop cycle as two distinct phases: the first one from early vegetative to flowering (pre-flowering) and the second one from flowering to maturity (post-flowering). For each of these two phases, one key descriptive parameter was identified, the potential sink size (PSS) at flowering for the pre-flowering phase, and the grain filling rate (FR) for the post-flowering phase. Significant correlations were observed for grain yield with both PSS and FR within maturity groups in both seasons, indicating the strong effect of both phases in grain yield establishment. Finally, relevant traits in the DS were those favoring light capture along the whole crop cycle in both maturity groups. Traits for the WS differed among maturity groups. Traits for the early maturity group were also those favoring light capture, while the same traits were non desirable for the medium and late maturity groups, for which delayed leaf senescence and short plant height were identified. The difference between relevant traits highlights the need of developing distinct breeding programs respective of the growing seasons and maturity groups.

The present paper focuses on the development of a population balance model (PBM) accounting for microbial population dynamics in a fluctuating environment. Heterogeneity within the cell population has two origins: extrinsic/intrinsic noises (cell to cell variability due to biological processes) and external noise (due to fluctuations in the cell environment). Modelling the effects of concentration gradients on the population heterogeneity was addressed in previous works using a population balance model based on the specific growth rate. However that model was unable to predict the distribution of specific growth rates experimentally observed at steady state. Using recent experimental data, we now propose a suitable law for the probability that cells growing at a given specific rate produce daughter cells with a different growth rate. Characteristic times of substrate assimilation and mixing at the cell scale are then combined to produce a generic model for substrate uptake limited by micromixing. The simulated results compare favorably to experimental observations leading to a robust multiscale model for bioreactor dynamics combining liquid-cell mass transfer and population heterogeneity.

Adaptation to local resource availability depends on responses in growth rate and nutrient acquisition. The growth rate hypothesis (GRH) suggests that growing fast should impair competitive abilities for phosphorus and nitrogen due to high demand for biosynthesis. However, in microorganisms, size influences both growth and uptake rates, which may mask trade-offs and instead generate a positive relationship between these traits (size hypothesis, SH). Here, we evolved a gradient of maximum growth rate (μmax) from a single bacterium ancestor to test the relationship amongμmax, competitive ability for nutrients and cell size, while controlling for evolutionary history. We found a strong positive correlation betweenμmaxand competitive ability for phosphorus, associated with a trade-off betweenμmaxand cell size: strains selected for highμmaxwere smaller and better competitors for phosphorus. Our results strongly support the SH, while the trade-offs expected under GRH were not apparent. Beyond plasticity, unicellular populations can respond rapidly to selection pressure through joint evolution of their size and maximum growth rate. Our study stresses that physiological links between these traits tightly shape the evolution of competitive strategies.

Context: In the Mediterranean area, numerous decline and mortality processes have been reported during recent decades, affecting forest dynamics. They are likely due to increases in summer drought severity and therefore especially affect drought-sensitive species, such as silver fir (Abies alba Mill.). [br/] [br/] Aims and methods: To understand the relationships between tree growth, crown condition and mortality probability, radial growth trends of healthy, declining (showing crown damages) and dead trees were compared using tree-ring analysis. Factors involved in determining this mortality were also examined at the plot and tree level using altitudinal gradients on three contrasted sites in southeastern France. [br/][br/] Results: Individuals with higher inter-annual variability in growth were more prone to dieback. At two sites, dead trees displayed lower growth rates over their entire lifetime, while, on the last site, their juvenile growth rate was higher. Trees with crown damage had higher growth rates than healthy trees on one site, and their radial growth trends over time always differed from those of dead trees.Mortality and crown damage were little related to altitude, but strongly differed between sites and among plots underlining the importance of local edaphic and topographic conditions.[br/] [br/] Conclusion: These results suggest that the relationships among mortality probability, crown condition and growth can differ among sites, and highlight the impact of soil conditions and the need to assess them in tree mortality studies.

International audience; The future of tropical managed forests is threatened by climate change. In anticipation of the increase in the frequency of drought episodes predicted by climatic models for intertropical regions, it is essential to study commercial trees' resilience and vulnerability to water stress by identifying potential interaction effects between selective logging and stress due to a lack of water. Focusing on 14 species representing a potential or acknowledged commercial interest for wood production in the Guiana Shield, a joint model coupling growth and mortality for each species was parametrized, including a climatic variable related to water stress and the quantity of aboveground biomass lost after logging. For the vast majority of the species, water stress had a negative impact on growth rate, while the impact of logging was positive. The opposite results were observed for the mortality. Combining results from growth and mortality models, we generate vulnerability profiles and ranking from species apparently quite resistant to water stress (Chrysophyllum spp., Goupia glabra Aubl., Qualea rosea Aubl.), even under logging pressure, to highly vulnerable species (Sterculia spp.). In light of our results, forest managers in the Guiana Shield may want to conduct (i) a conservation strategy of the most vulnerable species and (ii) a diversification of the logged species. Conservation of the already-adapted species may also be considered as the most certain way to protect the tropical forests under future climates.

The qTSN4 was identified as rice QTL (Quantitative Traits Locus) increasing total spikelet number per panicle and flag leaf area but potentially reducing panicle number depending on the environment. So far, this trade-off was mainly observed at grain maturity and not specifically studied in details, limiting the apprehension of the agronomic interest of qTSN4. This study aimed to understand the effect of qTSN4 and of the environment on panicle sizing, its trade-off with panicle number, and finally plant grain production. It compared two high yielding genotypes to their Near Isogenic Lines (NIL) carrying either QTL qTSN4 or qTSN12, two distinct QTLs contributing to the enlarged panicle size, thereafter designated as qTSN. Traits describing C sink (organ appearance rate, size, biomass) and source (leaf area, photosynthesis, sugar availability) were dynamically characterized along plant and/or panicle development within two trials (greenhouse, field), each comparing two treatments contrasting for plant access to light (with or without shading, high or low planting densities). The positive effect of qTSN on panicle size and flag leaf area of the main tiller was confirmed. More precisely, it could be shown that qTSN increased leaf area and internode cross-section, and in some cases of the photosynthetic rate and starch reserves, of the top 3-4 phytomers of the main tiller. This was accompanied by an earlier tillering cessation, that coincided with the initiation of these phytomers, and an enhanced panicle size on the main tiller. Plant leaf area at flowering was not affected by qTSN but fertile tiller number was reduced to an extent that depended on the environment. Accordingly, plant grain production was enhanced by qTSN only under shading in the greenhouse experiment, where panicle number was not affected and photosynthesis and starch storage in internodes was enhanced. The effect of qTSN on rice phenotype was thus expressed before panicle initiation (PI). Whether early tillering reduction or organ oversizing at meristem level is affected first cannot be entirely unraveled. Further studies are needed to better understand any signal involved in this early regulation and the qTSN × Environment interactions underlying its agronomic interest.

Cover crops introduced into cropping systems can lead to chemical input reductions and pollution mitigation because they enhance ecological functions. The choice of the best cover crops for a specific cropping system is, however, difficult because of the large range of potential cover species. A promising method involves functional traits as simplified indicators of plant functions. In banana cropping systems, cover crops are used especially to control weeds by development of their leaf area to boost competition for light. The aim of this study was to seek trait-based leaf area development strategies among tropical cover species, based on four plant traits chosen because of their mathematical link with leaf area development: specific leaf area (SLA), aboveground leaf mass fraction (LMFa), seed mass (SM) and aboveground relative growth rate (RGRa). We measured trait values and leaf areas of 17 tropical cover species grown for 1 month in a growth chamber. Strong positive and negative covariations were observed between SM, LMFa and RGRa, revealing a “syndrome” of traits and suggesting trade-offs between traits. Four groups of species were identified based on PCA and cluster analyses and were characterized by significantly different sets of trait values. They showed four leaf area development strategies: species that allocate a large part of biomass to leaf area (G1), species that develop large biomass and leaf area at emergence (G2), species with rapid biomass growth and low biomass investment in leaves (G3) and species with a non-specialized strategy (G4). After 1 month, species of groups G1 and G2 had higher leaf area, although not significantly, than species of groups G3 and G4. Comparisons between this functional classification and the taxonomic monocot/dicot classification showed that the functional classification captured a larger part of the variability in traits involved in leaf area development than the taxonomic monocot/dicot classification. This encourages the use of such a classification to describe plant functioning, to understand plant roles in plant–plant interactions and guide the choice of the best cover species to introduce into cropping systems.

Le taux de mortalité néonatale en élevage canin atteint 15 à 20% ce qui représente une perte économique importante. Un défaut de transfert passif d’immunité et/ou un défaut de transfert énergétique expliquent en partie ce résultat. La quantification de ces deux paramètres sur le terrain est complexe et invasive. A l’aide de données récupérées dans un élevage français d’octobre à novembre 2014 sur 62 chiots nous avons testé la corrélation entre neuf paramètres obtenus de façon non invasive et la concentration d’immunoglobulines sériques à J2 ainsi que la corrélation entre cinq paramètres et la glycémie à J1. Le paramètre le plus fiable pour détecter une concentration en IgG inférieure à 2,3g/L à J2 est l’activité sérique des GGT à J2 (sensibilité=87,5% ; spécificité = 80,0% ; Index de Youden = 0,7) avec une valeur seuil de 62,0 U/L. Seul le taux de croissance entre 12 et 18 heures est significativement corrélé à la glycémie à J1. Ce paramètre n’est toutefois pas un outil fiable de détection des chiots avec une glycémie inférieure à 92mg/dL à J1 (sensibilité = 100% ; spécificité = 10,1% ; Index de Youden = 0,1). Ce travail offre des perspectives nouvelles dans l’évaluation du statut immunitaire du chiot avec pour objectif de repérer les chiots à risque et de diminuer la mortalité en élevage canin.