Efficience de l'eau d'une culture de pomme de terre (Solanum tuberosum L. cv. Bintje) : 2. Application à un modèle de calcul d'assimilation nette du couvert végétal

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Здійснення адміністративно-територіальних реформ у місцях компактного проживання німців Криму в 20-30-х роках ХХ ст.

Статтю присвячено вивченню національної політики більшовиків у Криму на прикладі німців. Розкрито історію формування національних районів і селищних рад. Окремо розглянуто проведення більшовиками кадрової політики, динаміку розширення мережі національних сільських рад, проблеми переведення діловодства на німецьку мову. Показано, як сприймали німці національну політику радянської влади.Статья посвящена изучению национальной политики большевиков в Крыму на примере немцев. Раскрыта история формирования национальных районов и сельских советов. Отдельно рассмотрено проведение большевиками кадровой политики, динамику расширения сети национальных сельских советов, проблемы перевода делопроизводства на немецкий язык. Показано, как воспринимали немцы национальную политику советской власти.The article is devoted to the study of the national policy of the Bolsheviks in the Crimea on the example of the Germans. Reveals the history of the formation of national and rural councils. Separately, the Bolsheviks considered the holding of personnel policy, the dynamics of the expanding network of national rural councils, the problems associated with the transfer of proceedings in the German language. We show how Germans perceive the national policy of Soviet power

The SPARSE model for the prediction of water stress and evapotranspiration components from thermal infra-red data and its evaluation over irrigated and rainfed wheat

Evapotranspiration is an important component of the water cycle, especially in semi-arid lands. A way to quantify the spatial distribution of evapotranspiration and water stress from remote-sensing data is to exploit the available surface temperature as a signature of the surface energy balance. Remotely sensed energy balance models enable one to estimate stress levels and, in turn, the water status of continental surfaces. Dual-source models are particularly useful since they allow derivation of a rough estimate of the water stress of the vegetation instead of that of a soil–vegetation composite. They either assume that the soil and the vegetation interact almost independently with the atmosphere (patch approach corresponding to a parallel resistance scheme) or are tightly coupled (layer approach corresponding to a series resistance scheme). The water status of both sources is solved simultaneously from a single surface temperature observation based on a realistic underlying assumption which states that, in most cases, the vegetation is unstressed, and that if the vegetation is stressed, evaporation is negligible. In the latter case, if the vegetation stress is not properly accounted for, the resulting evaporation will decrease to unrealistic levels (negative fluxes) in order to maintain the same total surface temperature. This work assesses the retrieval performances of total and component evapotranspiration as well as surface and plant water stress levels by (1) proposing a new dual-source model named Soil Plant Atmosphere and Remote Sensing Evapotranspiration (SPARSE) in two versions (parallel and series resistance networks) based on the TSEB (Two-Source Energy Balance model, Norman et al., 1995) model rationale as well as state-of-the-art formulations of turbulent and radiative exchange, (2) challenging the limits of the underlying hypothesis for those two versions through a synthetic retrieval test and (3) testing the water stress retrievals (vegetation water stress and moisture-limited soil evaporation) against in situ data over contrasted test sites (irrigated and rainfed wheat). We demonstrated with those two data sets that the SPARSE series model is more robust to component stress retrieval for this cover type, that its performance increases by using bounding relationships based on potential conditions (root mean square error lowered by up to 11 W m−2 from values of the order of 50–80 W m−2), and that soil evaporation retrieval is generally consistent with an independent estimate from observed soil moisture evolution

Omega-3 Fatty Acids from Fish Oil Lower Anxiety, Improve Cognitive Functions and Reduce Spontaneous Locomotor Activity in a Non-Human Primate

Omega-3 (ω3) polyunsaturated fatty acids (PUFA) are major components of brain cells membranes. ω3 PUFA-deficient rodents exhibit severe cognitive impairments (learning, memory) that have been linked to alteration of brain glucose utilization or to changes in neurotransmission processes. ω3 PUFA supplementation has been shown to lower anxiety and to improve several cognitive parameters in rodents, while very few data are available in primates. In humans, little is known about the association between anxiety and ω3 fatty acids supplementation and data are divergent about their impact on cognitive functions. Therefore, the development of nutritional studies in non-human primates is needed to disclose whether a long-term supplementation with long-chain ω3 PUFA has an impact on behavioural and cognitive parameters, differently or not from rodents. We address the hypothesis that ω3 PUFA supplementation could lower anxiety and improve cognitive performances of the Grey Mouse Lemur (Microcebus murinus), a nocturnal Malagasy prosimian primate. Adult male mouse lemurs were fed for 5 months on a control diet or on a diet supplemented with long-chain ω3 PUFA (n = 6 per group). Behavioural, cognitive and motor performances were measured using an open field test to evaluate anxiety, a circular platform test to evaluate reference spatial memory, a spontaneous locomotor activity monitoring and a sensory-motor test. ω3-supplemented animals exhibited lower anxiety level compared to control animals, what was accompanied by better performances in a reference spatial memory task (80% of successful trials vs 35% in controls, p<0.05), while the spontaneous locomotor activity was reduced by 31% in ω3-supplemented animals (p<0.001), a parameter that can be linked with lowered anxiety. The long-term dietary ω3 PUFA supplementation positively impacts on anxiety and cognitive performances in the adult mouse lemur. The supplementation of human food with ω3 fatty acids may represent a valuable dietary strategy to improve behavioural and cognitive functions

Interactions surface continentale/atmosphère : l'expérience HAPEX-Sahel

Des données bioclimatiques recueillies sur une culture de mil dans le cadre de l'expérience Hapex-Sahel 1992, ont été utilisées pour paramétrer les divers compartiments d'un modèle de couvert épars composé de deux niveaux d'échanges : la surface du sol et la végétation. Il s'agit du modèle de Shuttleworth et Wallace (1985). Les entrées du modèle sont les données météorologiques classiques et les caractéristiques biologiques de la culture. En sortie, le modèle fournit les flux de chaleur latente et sensible, ainsi que les températures de surface du sol et de la plante. La paramétrisation a porté d'une part, sur la répartition de l'énergie disponible entre le sol et la végétation, et d'autre part, sur les principales résistances aux échanges des flux. L'utilisation du modèle sur l'ensemble du cycle du mil, permet une estimation horaire et journalière de l'évapotranspiration (ETR) satisfaisante, avec la possibilité de calculer séparément la transpiration de la plante et l'évaporation du sol. Les valeurs d'ETR estimées par le modèle concordent bien avec celles mesurées au-dessus de la culture par la méthode du bilan d'énergie/rapport de Bowen. Cette concordance est encore meilleure pendant la phase de végétation maximale. L'analyse de l'évolution de la transpiration de la plante et de l'évaporation du sol au cours du cycle cultural montre que l'évaporation du sol dépasse le seuil de 50% ETR, du début du cycle jusqu'au stade de LAI = 1,5. Sur l'ensemble du cycle, l'évaporation du sol est de l'ordre de 40% ETR. (Résumé d'auteur

Retrieving air humidity, global solar radiation, and reference evapotranspiration from daily temperatures : development and validation of new methods for Mexico. Part III : reference evapotranspiration

We evaluated two methods to estimate evapotranspiration (ETo) from minimal weather records (daily maximum and minimum temperatures) in Mexico: a modified reduced set FAO-Penman-Monteith method (Allen et al. 1998, Rome, Italy) and the Hargreaves and Samani (Appl Eng Agric 1(2): 96-99, 1985) method. In the reduced set method, the FAO-Penman-Monteith equation was applied with vapor pressure and radiation estimated from temperature data using two new models (see first and second articles in this series): mean temperature as the average of maximum and minimum temperature corrected for a constant bias and constant wind speed. The Hargreaves-Samani method combines two empirical relationships: one between diurnal temperature range Delta T and short-wave radiation Rs, and another one between average temperature and the ratio ETo/Rs: both relationships were evaluated and calibrated for Mexico. After performing a sensitivity analysis to evaluate the impact of different approximations on the estimation of Rs and ETo, several model combinations were tested to predict ETo from daily maximum and minimum temperature alone. The quality of fit of these models was evaluated on 786 weather stations covering most of the territory of Mexico. The best method was found to be a combination of the FAO-Penman-Monteith reduced set equation with the new radiation estimation and vapor pressure model. As an alternative, a recalibration of the Hargreaves-Samani equation is proposed

Retrieving air humidity, global solar radiation, and reference evapotranspiration from daily temperatures : development and validation of new methods for Mexico. Part I : humidity

This study evaluates the dew point method (Allen et al. 1998) to estimate atmospheric vapor pressure from minimum temperature, and proposes an improved model to estimate it from maximum and minimum temperature. Both methods were evaluated on 786 weather stations in Mexico. The dew point method induced positive bias in dry areas but also negative bias in coastal areas, and its average root mean square error for all evaluated stations was 0.38 kPa. The improved model assumed a bi-linear relation between estimated vapor pressure deficit (difference between saturated vapor pressure at minimum and average temperature) and measured vapor pressure deficit. The parameters of these relations were estimated from historical annual median values of relative humidity. This model removed bias and allowed for a root mean square error of 0.31 kPa. When no historical measurements of relative humidity were available, empirical relations were proposed to estimate it from latitude and altitude, with only a slight degradation on the model accuracy (RMSE = 0.33 kPa, bias = -0.07 kPa). The applicability of the method to other environments is discussed