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Changing landscapes of Southeast Asia and rodent‐borne diseases: decreased diversity but increased transmission risks
No full textThe reduction in biodiversity from land use change due to urbanization and agricultural intensification appears to be linked to major epidemiological changes in many human diseases. Increasing disease risks and the emergence of novel pathogens result from increased contact among wildlife, domesticated animals, and humans. We investigated the relationship between human alteration of the environment and the occurrence of generalist and synanthropic rodent species in relation to the diversity and prevalence of rodent-borne pathogens in Southeast Asia, a hotspot of threatened and endangered species, and a foci of emerging infectious diseases. We used data from an extensive pathogen survey of rodents from seven sites in mainland Southeast Asia in conjunction with past and present land cover analyses. At low spatial resolutions, we found that rodent-borne pathogen richness is negatively associated with increasing urbanization, characterized by increased habitat fragmentation, agriculture cover and deforestation. However, at a finer spatial resolution, we found that some major pathogens are favored by environmental characteristics associated with human alteration including irriga-
tion, habitat fragmentation, and increased agricultural land cover. In addition, synanthropic rodents, many of which are important pathogen reservoirs, were associated with fragmented and human-dominated landscapes, which may ultimately enhance the opportunities for zoonotic transmission and human infection by some pathogens
A meta-analysis of the price and income elasticities of food demand
No full textFood demand elasticities are crucial parameters in the calibration of simulation models used to assess the impacts of political reforms or to analyse long-term projections, notably in agricultural sectors. Numerous estimates of these parameters are now available in the economic literature. The main objectives of this work are twofold: we seek first to identify general patterns characterizing the demand elasticities of food products and second to identify the main sources of heterogeneity between the elasticity estimates available in the literature. To achieve these objectives, we conduct a broad literature review of food demand elasticity estimates and perform a meta-regression analysis.
Our results reveal the important impacts of income levels on income and price elasticities both at the country (gross domestic product-GDP) and household levels: the higher the income is, the lower the level of elasticities. Food demand responses to changes in income and prices appear to follow different patterns depending on the global regions involved apart from any income level consideration. From a methodological viewpoint, the functional forms used to represent food demand are found to significantly affect elasticity estimates. This result sheds light on the importance of the specification of demand functions, and particularly of their flexibility, in simulation models.Les élasticités prix et revenu de la demande de biens alimentaires sont des paramètres cruciaux intervenant dans le calibrage des modèles de simulation qui sont utilisés pour évaluer l’impact de réformes politiques ou faire des projections de long terme, notamment en ce qui concerne dans les secteurs agricoles. De nombreuses valeurs estimées de ces paramètres sont aujourd’hui disponibles dans la littérature économique. Nos principaux objectifs ici sont, d’une part, de mettre en avant des éléments caractérisant de manière générale ces élasticités prix et revenu et, d’autre part, d’identifier les principales sources de variabilité de leurs valeurs estimées dans la littérature. Pour répondre à ce double objectif nous collectons dans la littérature un large ensemble d’élasticités estimées de demande de biens alimentaires que nous analysons ensuite à l’aide d’une méta-régression.
Nos résultats mettent en évidence un impact important du niveau de revenu, à la fois au niveau pays (produit intérieur brut-PIB) et au niveau ménage, sur les élasticités prix et revenu : plus le revenu est élevé, moins la demande de biens alimentaires est élastique. Il apparait également que les réponses de la demande aux variations de revenu et de prix diffèrent entre régions du monde indépendamment des différences de revenus pouvant exister entre ces régions. D’un point de vue méthodologique, nous trouvons que le choix de la forme fonctionnelle utilisée pour représenter la demande a un effet significatif sur les élasticités estimées. Ce résultat souligne l’importance de la spécification des fonctions de demande, en particulier de leur flexibilité, dans les modèles de simulation
understanding properties of casein micelles concentrated layers during crossflow filtration
No full textOn a cold night: transcriptomics of grapevine flower unveils signal transduction and impacted metabolism
No full textLow temperature is a critical environmental factor limiting plant productivity, especially in northern vineyards. To clarify the impact of this stress on grapevine flower, we used the Vitis array based on Roche-NimbleGen technology to investigate the gene expression of flowers submitted to a cold night. Our objectives were to identify modifications in the transcript levels after stress and during recovery. Consequently, our results confirmed some mechanisms known in grapes or other plants in response to cold stress, notably, (1) the pivotal role of calcium/calmodulin-mediated signaling; (2) the over-expression of sugar transporters and some genes involved in plant defense (especially in carbon metabolism), and (3) the down-regulation of genes encoding galactinol synthase (GOLS), pectate lyases, or polygalacturonases. We also identified some mechanisms not yet known to be involved in the response to cold stress, i.e., (1) the up-regulation of genes encoding G-type lectin S-receptor-like serine threonine-protein kinase, pathogen recognition receptor (PRR5), or heat-shock factors among others; (2) the down-regulation of Myeloblastosis (MYB)-related transcription factors and the Constans-like zinc finger family; and (3) the down-regulation of some genes encoding Pathogen-Related (PR)-proteins. Taken together, our results revealed interesting features and potentially valuable traits associated with stress responses in the grapevine flower. From a long-term perspective, our study provides useful starting points for future investigation
Divergent national-scale trends of microbial and animal biodiversity revealed across diverse temperate soil ecosystems
No full textSoil biota accounts for similar to 25% of global biodiversity and is vital to nutrient cycling and primary production. There is growing momentum to study total belowground biodiversity across large ecological scales to understand how habitat and soil properties shape belowground communities. Microbial and animal components of belowground communities follow divergent responses to soil properties and land use intensification; however, it is unclear whether this extends across heterogeneous ecosystems. Here, a national-scale metabarcoding analysis of 436 locations across 7 different temperate ecosystems shows that belowground animal and microbial (bacteria, archaea, fungi, and protists) richness follow divergent trends, whereas beta-diversity does not. Animal richness is governed by intensive land use and unaffected by soil properties, while microbial richness was driven by environmental properties across land uses. Our findings demonstrate that established divergent patterns of belowground microbial and animal diversity are consistent across heterogeneous land uses and are detectable using a standardised metabarcoding approach
Etude des règles de transfert des biomasses produites et valorisées sur les sols agricoles à la Réunion
No full textNonparametric estimation of R&D international spillovers
No full textWe revisit the issue of international technology diffusion within the framework of large panels with strong cross-sectional dependence by adopting a method which extends the Common Correlated Effects (CCE) approach to nonparametric specifications. Our results indicate that the adoption of a nonparametric approach provides significant benefits in terms of predictive ability. This work also refines previous results by showing threshold effects, nonlinearities and interactions, which are obscured in parametric specifications and which have relevant policy implications
Pretreatment and gaseous radiocarbon dating of 40-100 mg archaeological bone
No full textRadiocarbon dating archaeological bone typically requires 300-1000 mg material using standard protocols. We report the results of reducing sample size at both the pretreatment and C-14 measurement stages for eight archaeological bones spanning the radiocarbon timescale at different levels of preservation. We adapted our standard collagen extraction protocol specifically for <100 mg bone material. Collagen was extracted at least twice (from 37-100 mg material) from each bone. Collagen aliquots containing <100 mu g carbon were measured in replicate using the gas ion source of the AixMICADAS. The effect of sample size reduction in the EA-GIS-AMS system was explored by measuring C-14 of collagen containing either ca. 30 mu g carbon or ca. 90 mu g carbon. The gas dates were compared to standard-sized graphite dates extracted from large amounts (500-700 mg) of bone material pretreated with our standard protocol. The results reported here demonstrate that we are able to reproduce accurate radiocarbon dates from <100 mg archaeological bone material back to 40,000 BP
Moderate plant water stress improves larval development, and impacts immunity and gut microbiota of a specialist herbivore
No full textWhile host plant drought is generally viewed as a negative phenomenon, its impact on insect herbivores can vary largely depending on the species involved and on the intensity of the drought. Extreme drought killing host plants can clearly reduce herbivore fitness, but the impact of moderate host plant water stress on insect herbivores can vary, and may even be beneficial. The populations of the Finnish Glanville fritillary butterfly (Melitaea cinxia) have faced reduced precipitation in recent years, with impacts even on population dynamics. Whether the negative effects of low precipitation are solely due to extreme desiccation killing the host plant or whether moderate drought reduces plant quality for the larvae remains unknown. We assessed the performance of larvae fed on moderately water-stressed Plantago lanceolata in terms of growth, survival, and immune response, and additionally were interested to assess whether the gut microbial composition of the larvae changed due to modification of the host plant. We found that larvae fed on water-stressed plants had increased growth, with no impact on survival, up-regulated the expression of one candidate immune gene (pelle), and had a more heterogeneous bacterial community and a shifted fungal community in the gut. Most of the measured traits showed considerable variation due to family structure. Our data suggest that in temperate regions moderate host plant water stress can positively shape resource acquisition of this specialized insect herbivore, potentially by increasing nutrient accessibility or concentration. Potentially, the better larval performance may be mediated by a shift of the microbiota on water-stressed plants, calling for further research especially on the understudied gut fungal community