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Towards the quantitative characterisation of piglets’ robustness to weaning: a modelling approach
No full textWeaning is a critical transition phase in swine production in which piglets must cope with different stressors that may affect their health. During this period, the prophylactic use of antibiotics is still frequent to limit piglet morbidity, which raises both economic and public health concerns such as the appearance of antimicrobial-resistant microbes. With the interest of developing tools for assisting health and management decisions around weaning, it is key to provide robustness indexes that inform on the animals’ capacity to endure the challenges associated with weaning. This work aimed at developing a modelling approach for facilitating the quantification of piglet resilience to weaning. A total of 325 Large White pigs weaned at 28 days of age were monitored and further housed and fed conventionally during the post-weaning period without antibiotic administration. Body weight and diarrhoea scores were recorded before and after weaning, and blood was sampled at weaning and 1 week later for collecting haematological data. A dynamic model was constructed based on the Gompertz–Makeham law to describe live weight trajectories during the first 75 days after weaning, following the rationale that the animal response is partitioned in two time windows (a perturbation and a recovery window). Model calibration was performed for each animal. Our results show that the transition time between the two time windows, as well as the weight trajectories are characteristic for each individual. The model captured the weight dynamics of animals at different degrees of perturbation, with an average coefficient of determination of 0.99, and a concordance correlation coefficient of 0.99. The utility of the model is that it provides biologically meaningful parameters that inform on the amplitude and length of perturbation, and the rate of animal recovery. Our rationale is that the dynamics of weight inform on the capability of the animal to cope with the weaning disturbance. Indeed, there were significant correlations between model parameters and individual diarrhoea scores and haematological traits. Overall, the parameters of our model can be useful for constructing weaning robustness indexes by using exclusively the growth curves. We foresee that this modelling approach will provide a step forward in the quantitative characterisation of robustness
What makes plant succumb under drought conditions: A tissue-level approach to understand and identify tree mortality
No full textLes modèles climatiques globaux prévoient une augmentation de la fréquence et de l’intensité des sécheresses affectant la survie des arbres. Afin d’améliorer la précision des modèles mécanistiques prédisant la mort des arbres, il apparait crucial de comprendre ces processus en condition de sécheresse extrême et d’identifier les seuils physiologiques clés au-delà desquels les arbres meurent. Ainsi, l’objectif principal de cette étude était d’identifier les traits physiologiques clés, à l’échelle tissulaire, pouvant servir de seuil de mortalité chez les arbres. Pour cela, plusieurs individus de deux espèces différentes ont été exposé à un événement de sécheresse et leur capacité à récupérer a été suivie après leur réhydratation. Les résultats montrent que les pourcentages de perte de conductance hydraulique communément acceptés comme des seuils de mortalité (P50 pour les conifères et P88 pour les angiospermes) ne seraient qu’une vague approximation de la capacité des arbres à survivre. Cependant, aucun des traits physiologiques suivi n’a pu déterminer un seuil identifiant la mort des arbres. La présence de cellules vivantes au niveau de l’écorce et du phloème permet de postuler que les arbres pourraient survivre à un événement de sécheresse si la continuité hydraulique entre les racines et les cellules vivantes était maintenue
Measuring food waste and consumption by children using photography
No full textA photography method was used to measure waste on food trays in school lunch in France, using the 5-point quarter-waste scale. While food waste has been studied extensively in US school lunches, the structure of the French lunch meal is quite different, with multiple courses, and vegetables (raw and cooked) in more than one course. Vegetables were the most wasted food category as usually seen in school lunch research, especially cooked vegetables, which were wasted at rates of 66%–83%. Raw vegetables were still wasted more than main dishes, starchy products, dairy, fruit, and desserts. Vegetables were also the most disliked food category, with the classes of vegetables falling in the same order as for waste. Waste and liking were highly correlated. Sensory characteristics of the food were cited as a main reason for liking/disliking. There is a strong connection between food liking and food consumption, and this connection should be the basis for future attempts to modify school lunch to improve consumption. The photographic method of measuring food waste at an individual level performed well
Diversity of the socio-economic strategies of valorization of the undergrowth of Guadeloupe: a typology
No full textReal-world outcomes of observation and treatment in diabetic macular edema with very good visual acuity: the OBTAIN study
No full textTo describe and compare the functional and anatomical outcomes of untreated and treated diabetic macular edema (DME) in eyes with very good baseline visual acuity (VA) in a real-world setting
A Modeling Approach to Diagnose the Impacts of Global Changes on Discharge and Suspended Sediment Concentration within the Red River Basin
No full textThe Red River basin is a typical Asian river system affected by climate and anthropogenicchanges. The purpose of this study is to build a tool to separate the effect of climate variability andanthropogenic influences on hydrology and suspended sediments. A modeling method combiningin situ and climatic satellite data was used to analyze the discharge (Q) and suspended sedimentconcentration (SSC) at a daily time scale from 2000 to 2014. Scenarios of natural and actual conditionswere implemented to quantify the impacts of climate variability and dams. The modeling gainedsatisfactory simulation results of water regime and SSC compared to the observations. Under naturalconditions, the Q and SSC show decreasing tendencies, and climate variability is the main influencefactor reducing the Q. Under actual conditions, SSC is mainly reduced by dams. At the outlet, annualmean Q got reduced by 13% (9% by climate and 4% by dams), and annual mean SSC got reducedto 89% (13% due to climate and 76% due to dams) of that under natural conditions. The climatetendencies are mainly explained by a decrease of 9% on precipitation and 5% on evapotranspiration,which results in a 13% decrease of available water for the whole basin
Different phenotypic plastic responses to predators observed among aphid lineages specialized on different host plants
No full textThe role of intraspecific variation in the magnitude and direction of plastic responses in ecology and evolution is increasingly recognized. However, the factors underlying intraspecific variation in plastic responses remain largely unexplored, particularly for the hypothesis that the herbivores' phenotypic response to predators might vary amongst lineages associated with different host plants. Here, we tested whether plant-specialized lineages of the pea aphid, Acyrthosiphon pisum, differed in their transgenerational phenotypic response to ladybird predators (i.e., the asexual production of winged offspring by wingless mothers). In a full factorial laboratory experiment, we found that six aphid clonal lineages each specialized either on alfalfa or clover significantly differed in their transgenerational phenotypic response to predators. Some lineages produced an increased number of winged aphids in predator presence while others did not respond. Aphid lineages specialized on alfalfa had stronger phenotypic responses to predators than those specialized on clover. Although we tested only six aphid lineages from two biotypes, our results imply that intraspecific variation in prey phenotypic response of herbivores to predators differs amongst lineages specialized on different host plants. Our findings therefore raise the question of the influence of plant specialization in shaping herbivore phenotypic responses, and highlight the need to consider multi-trophic interactions to understand the causes and consequences of intraspecific variation in complex phenotypic traits
P-glycoprotein 1 affects chemoactivities of resveratrol against human colorectal cancer cells
No full textResveratrol has been proposed to prevent tumor growth and the di_erent steps of carcinogenesis; nevertheless, these biological e_ects are sometimes discordant between di_erent cell types. Several hypotheses and works have suggested that the metabolism of resveratrol could be at the origin of a di_erent cellular response. We show here, using colorectal tumor cell lines, that the biological e_ects of RSV result mainly from its carriage by carriers of the superfamily of ABC transporter, i.e., P-gP, MRP, or BCRP. Using cell lines overexpressing these di_erent transporters, we have been able to highlight the importance of P-gP in the response of cells to RSV. These results were confirmed by invalidating the gene coding for P-gP, which restored the sensitivity of colorectal cells resistant to the polyphenol. Subsequently, the status of P-glycoprotein expression is an important element to be taken into consideration in the cytotoxic activity of resveratrol in colorectal cancer cells