Methodes de stockage permettant de conserver intactes sur de longues durees des arachides decortiquees et triees destinees a la consommation en arachides de bouche et aux semences. Caracteristiques ...du stockage refrigere et du stockage sous vide avec reinjection d' azote. Avantages et inconvenients de ces methodes en fonction des equipements disponibles au Senegal.
Pasture species undergo successive cycles of defoliation and re-growth, which differ in frequency and in intensity. This partial (or total) removal of photosynthetic tissues decreases the ...assimilation of carbon dioxyde. This decrease is accompanied in legumes by a reduced fixation of atmospheric nitrogen, and by a reduced uptake of nitrate and ammonium. Plants respond to this by mobilizing C and N reserve substances stored in the uncut parts, in order to secure new growth. The role of these reserves mobilized to the re-growing tissues was reassessed in several experiments on Perennial Rye grass, White Clover and Lucerne. The effects of management and of environmental factors on N reserve storage are discussed. In legumes, low nitrogen reserves on the day of defoliation led to a reduced re-growth, but in certain grasses, a certain compensation took place, through an increased uptake of nitrogen.
Les espèces prairiales sont soumises à des défoliations successives qui réduisent fortement la quantité de CO2 assimilé et l'absorption d'azote. Afin d'assurer sa croissance après la coupe, la plante mobilise vers les tissus aériens en croissance certains substrats carbonés et azotés stockés dans les tissus laissés en place par la coupe. Pour assurer la productivité et la pérennité du couvert par une bonne gestion, il importe de bien identifier ces mécanismes d'adaptation. Les substrats carbonés et azotés mis en réserve sont disponibles dans les tissus laissés en place par la coupe (racines, pivots, tiges, stolons, base des feuilles). Différentes expérimentations sur ray-grass anglais, trèfle blanc, luzerne ont permis d'évaluer le rôle de ces réserves mobilisées vers les tissus en repousse. Les incidences actuellement connues des modes de défoliation (selon leur rythme et leur intensité) et de certains facteurs environnementaux sur ces réserves sont abordées. Chez les légumineuses, il apparaît qu'une plus faible disponibilité en réserves azotées au moment de la coupe se traduit par une réduction du potentiel de repousse alors que chez certaines graminées une compensation intervient suite à une augmentation de l'absorption d'azote par la plante.
Corn silage is the main forage fed to ruminants and represents the most important energetic supply to animals of high level of production (dairy cows and fattening animals). Global methods to predict ...organic matter digestibility of corn silage were developed in the 1990’s (Aufrère et al., 1992). To improve the understanding and the prediction of corn energetic substrates degradation in the rumen, one problem lies in the lack of reference method to evaluate the rate and extent of corn silage starch degradation in the rumen. This issue could lead to errors in the choice of feed supplements in diet formulation. The aim of the present experiment was to determine the most adapted experimental in sacco procedure among current in sacco incubation technique to evaluate degradability of fresh corn and corn silage.
•We developed a sensitive gas chromatography tandem mass spectrometry method for the determination of bisphenol A in foodstuffs.•We carried out a full validation.•Environmental contamination and ...analytical pitfalls are discussed.•The method allows the quantification at low trace level: sub 0.1μgkg−1.•Efficiency has been assessed in the frame of the 2nd French Total Diet Study (TDS).
BPA-containing products are widely used in foodstuffs packaging as authorized within the European Union (UE no. 10/2011). Therefore, foods and beverages are in contact with BPA which can migrate from food contact material to foodstuffs. An accurate assessment of the exposure of the consumers to BPA is crucial for a non-ambiguous risk characterization. In this context, an efficient analytical method using gas chromatography coupled to tandem mass spectrometry (GC–MS/MS), in the selected reaction monitoring (SRM) mode, was developed for the quantification of BPA in foodstuffs at very low levels (<0.5μgkg−1). A standard operating procedure, based on the combination of two successive solid phase extractions (SPE), was developed for various liquid and solid foodstuffs. The use of 13C12-BPA as internal standard allowed accurate quantification of BPA by isotopic dilution. Control charts based on both blank and certified materials have been implemented to ensure analytical data quality. The developed analytical method has been validated according to in-house validation requirements. R2 was better than 0.9990 within the range 0-100μgkg−1, the trueness was 4.2%. Repeatability and within-laboratory reproducibility ranged from 7.5% to 19.0% and 2.5% to 12.2%, respectively, at 0.5 and 5.0μgkg−1 depending on the matrices tested for. The detection and quantification limits were 0.03 and 0.10μgkg−1, respectively. The reporting limit was 0.35μgkg−1, taking into account the mean of the laboratory background contamination. The global uncertainty was 22.2% at 95% confidence interval.
Fiches techniques de 2 varietes d' arachide a cycle court issues des programmes de selection du Burkina Faso : - La CN94C diffusee dans le Centre et le Nord du pays est une Spanish de bonnes ...productivite et caracteristiques technologiques; - La QH243C est un hybride Spanish x Virginia a cycle court resistant a la rosette destine aux zones assez pluvieuses, d' excellente productivite.
Soil moisture profile effect on radar signal measurement Le Morvan , A. (Centre National de la Recherche Scientifique, Vélizy(France). CETP, Centre d'Etudes des Environnements Terrestre et Planétaires); Zribi , M. (Centre National de la Recherche Scientifique, Vélizy(France). CETP, Centre d'Etudes des Environnements Terrestre et Planétaires); Baghdadi , N. (Bureau de Recherches Géologiques et Minières, Orléans(France).) ...
2008
Publication
The objective of this paper is to analyze the behaviour of a backscattered signal according to soil moisture depth over bare soils. Analysis based on experimental vertical moisture profiles and ...ASAR/ENVISAT measurements has been carried out. A modified IEM model with three permittivity layers (0-1cm, 1-2cm, 2-5cm) has been developed and used in this study. Results show a small effect of moisture profile on the backscattered signal (less than 0.5dB). However, measurements and simulations have provided a more detailed insight into the behaviour of the radar signal and have shown that it was important to consistently use the same protocol when performing ground truth measurements of soil moisture.
Context.
In this Letter we aim to explore whether gas is also expected in the Kuiper belt (KB) in our Solar System.
Aims.
To quantify the gas release in our Solar System, we use models for gas ...release that have been applied to extrasolar planetary systems as well as a physical model that accounts for gas released due to the progressive internal warming of large planetesimals.
Methods.
We find that only bodies larger than about 4 km can still contain CO ice after 4.6 Gyr of evolution. This finding may provide a clue as to why Jupiter-family comets, thought to originate in the KB, are deficient in CO compared to Oort cloud comets. We predict that gas is still currently being produced in the KB at a rate of 2 × 10
−8
M
⊕
Myr
−1
for CO and that this rate was orders of magnitude higher when the Sun was younger. Once released, the gas is quickly pushed out by the solar wind. Therefore, we predict a gas wind in our Solar System starting at the KB location and extending far beyond with regards to the heliosphere, with a current total CO mass of ∼2 × 10
−12
M
⊕
(i.e., 20 times the CO quantity that was lost by the Hale-Bopp comet during its 1997 passage) and CO density in the belt of 3 × 10
−7
cm
−3
. We also predict the existence of a slightly more massive atomic gas wind made of carbon and oxygen (neutral and ionized), with a mass of ∼10
−11
M
⊕
.
Results.
We predict that gas is currently present in our Solar System beyond the KB and that, although it cannot be detected with current instrumentation, it could be observed in the future with an in situ mission using an instrument similar to Alice on New Horizons but with larger detectors. Our model of gas release due to slow heating may also work for exoplanetary systems and provide the first real physical mechanism for the gas observations. Lastly, our model shows that the amount of gas in the young Solar System should have been orders of magnitude greater and that it may have played an important role in, for example, planetary atmosphere formation.
A combined approach integrating bioenergetics and major biological activities is essential to properly understand the impact of microplastics (MP) on marine organisms. Following experimental exposure ...of polystyrene microbeads (micro-PS of 6 and 10 μm) at 0.25, 2.5, and 25 μg L−1, which demonstrated a dose-dependent decrease of energy balance in the pearl oyster Pinctada margaritifera, a transcriptomic study was conducted on mantle tissue. Transcriptomic data helped us to decipher the molecular mechanisms involved in P. margaritifera responses to micro-PS and search more broadly for effects on energetically expensive maintenance functions. Genes related to the detoxification process were impacted by long-term micro-PS exposure through a decrease in antioxidant response functioning, most likely leading to oxidative stress and damage, especially at higher micro-PS doses. The immune response was also found to be dose-specific, with a stress-related activity stimulated by the lowest dose present after a 2-month exposure period. This stress response was not observed following exposure to higher doses, reflecting an energy-limited capacity of pearl oysters to cope with prolonged stress and a dramatic shift to adjust to pessimum conditions, mostly limited and hampered by a lowered energetic budget. This preliminary experiment lays the foundation for exploring pathways and gene expression in P. margaritifera, and marine mollusks in general, under MP exposure. We also propose a conceptual framework to properly assess realistic MP effects on organisms and population resilience in future investigations.
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•Antioxidant and detoxification processes are impacted by long-term polystyrene microbeads exposure in P. margaritifera.•Energy metabolism and immunity are dose specific response to micro-PS exposure.•Bioenergetics and transcriptomics refine the energy-limited tolerance to stress concept for emerging pollutants.
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