Criblage in vitro des graines d’accessions locales de ricin (Ricinus communis L.) en conditions de stress salin

Le ricin (Ricinus communis L.) est une plante peu exigeante dont la culture offre d’énormes potentialités économiques pour les exploitants agricoles sénégalais. L’identification de génotypes performants avec des rendements acceptables en conditions de stress salin constitue une des solutions pour promouvoir cette culture sur des sols inaffectés aux cultures vivrières. Quatre accessions locales de ricin ont été cultivées durant un mois sur le milieu de Murashige et Skoog (MS) modifié et additionné de 0 ; 25 ; 50 ; 100 et 150 mM de chlorure de sodium (NaCl). Les réponses des accessions ont été évaluées en conditions in vitro sur la base de paramètres morphologiques, biochimiques et de survie des vitroplants. L’effet de la salinité sur ces paramètres mesurés a permis de classer les accessions en groupe tolérant (acc1), moyennement tolérant (acc7) et sensible (acc3 et acc4). La concentration 50 mM de NaCl a été identifiée comme un seuil de tolérance critique et discriminant permettant une classification des accessions de ricin selon leur sensibilité au NaCl. La biomasse aérienne est apparue comme un critère pertinent pour classer les accessions de ricin. Les mesures des teneurs en chlorophylle des feuilles des vitroplants ont permis d’aboutir à la même classification des groupes.Mots clés: criblage, Ricinus communis, salinité, SénégalEnglish Title:  In vitro screening of local accessions of castor bean seeds (Ricinus communis l.) Under conditions of salinity stressEnglish AbstractCastor bean (Ricinus communis L.) is an undemanding plant whose cultivation has enormous economic potential for Seneg alese farmers. The identification of efficient genotypes tolerant to salt stress condition could constitute a significant result to promote ricin culture specifically in margin soils. Four local accessions of castor were cultivated, using in vitro conditions for four weeks on MS modified medium supplemented with 0, 25, 50, 100, 150 mM NaCl. In vitro plants responses to salinity were recorded in terms of morphological and biochemical parameters and the rate of plant survival. The effect of different levels of salinity on these parameters was used to classify the accessions in tolerant group (acc1), moderately tolerant (acc7) and sensitive (acc3 and acc4). The concentration 50 mM of NaCl was identified as a discriminant level for castor accessions classification and a critical level of tolerance. The in vitro plants shoot biomass, appeared a relevant parameter to be used for classification of castor accessions under in vitro conditions. The content of leaf chlorophyll for in vitro plants confirmed the classification of Castor bean accessions obtained with morphological parameters according to their sensitivity to the salinity.Keywords: screening, Ricinus communis, salinity, Senega

Experimental study of slow sand filtration for the treatment of various wastewaters in tropical environment

Wastewater treatment by slow sand filtration is a biological process which consists in filtering wastewater through a porous media. The objective of this study was to evaluate the performances of this biotechnology under tropical climate. Three sand filters were monitored at ONAS (Cambérène wastewater treatment plant in Dakar, Senegal). The filters were built with local materials, and were constituted with a feeding tank of approximately 180 litters, a column (two meters high and 30-25 cm diameter). The filters were filled with sand (75 cm), gravel (25 cm) and wastewater (90 cm). The results showed that with sand of d10 equal to 0.58 mm and flow rate of 0.05 m/h, the filtration cycle was relatively long for the first run with pretreated wastewater. At the level of the primary settling tank, with flow a rate of 0.08 m/h, the removal rates were about 12.75%, 16.31%, 12.92%, 5.45%, 7.09% and 10.50% for TSS, COD, BOD5, nitrogen phosphorus and faecal coliforms respectively. At the level of the clarifier, with a filtration of 0.15 m/h, the removals were 1.4% for TSS, 1.84% for COD, 1.09% for BOD5 11.38% for nitrogen, 5.18% for phosphorus and 1.74% of faecal coliforms.Keywords: Flow rate; filtration cycle, removal; sand filtration; tropical climate, wastewater

Atomic correlations in itinerant ferromagnets: quasi-particle bands of nickel

We measure the band structure of nickel along various high-symmetry lines of the bulk Brillouin zone with angle-resolved photoelectron spectroscopy. The Gutzwiller theory for a nine-band Hubbard model whose tight-binding parameters are obtained from non-magnetic density-functional theory resolves most of the long-standing discrepancies between experiment and theory on nickel. Thereby we support the view of itinerant ferromagnetism as induced by atomic correlations.Comment: 4 page REVTeX 4.0, one figure, one tabl

Signature of quantum criticality in photoemission spectroscopy at elevated temperature

A quantum phase transition (QPT) in a heavy-fermion (HF) compound may destroy the Fermi liquid groundstate. However, the conditions for this breakdown have remained obscure. We report the first direct investigation of heavy quasiparticle formation and breakdown in the canonical system CeCu$_{6-x}$Au$_x$ by ultraviolet photoemission spectroscopy at elevated temperatures without the complications of lattice coherence. Surprisingly, the single-ion Kondo energy scale $T_K$ exhibits an abrupt step near the quantum critical Au concentration of $x_c=0.1$. We show theoretically that this step is expected from a highly non-linear renormalization of the local spin coupling at each Ce site, induced by spin fluctuations on neighboring sites. It provides a general high-temperature indicator for HF quasiparticle breakdown at a QPT.Comment: Published version, PRL, minor changes in wordin

Demand-Side Food Policies for Public and Planetary Health

Background: The current food system has major consequences for the environment and for human health. Alignment of the food policy areas of mitigating climate change and public health will ensure coherent and effective policy interventions for sustaining human health and the environment. Thispaperexploresliteratureondemand-sidepoliciesthataimtoreduceconsumptionof animal-basedfoods,increaseplant-basedfoods,andreduceoverconsumption. Methods:Wesearched for publications, published between January 2000 and December 2019, considering the above policy domains. Articles were distinguished for type of policy instrument, for topic via keywords and examples were given. Results: The majority of demand-side policies focus on preventing overweight and obesity, using all types of policy instruments including more forceful market-based policies. Hardly any examples of public policies explicitly aiming to lower animal-based foods consumption were found. Policies combining health and sustainability objectives are few and mainly of the information type. Discussion: Moving towards environmentally sustainable and healthy diets is challenging as the implemented demand-side policies focus largely on human health, and not yet on environmental outcomes, or on win-wins. Policies targeting foods from the health perspective can contribute to lower environmental impacts, by indicating suitable animal-based food replacers, and aiming at avoiding overconsumption of energy dense-nutrient poor foods. Preferred policies include a variety of instruments, including strong measures. Conclusions: Working solutions are available to ensure coherent and effective demand side food policies aligning public health and environmental aims. Implementation of aligned and effective policy packages is urgent and needed.© 2020 by the authorspublishedVersio

Temperature dependence of the Kondo resonance and its satellites in CeCu_2Si_2

We present high-resolution photoemission spectroscopy studies on the Kondo resonance of the strongly-correlated Ce system CeCu$_2$Si$_2$. Exploiting the thermal broadening of the Fermi edge we analyze position, spectral weight, and temperature dependence of the low-energy 4f spectral features, whose major weight lies above the Fermi level $E_F$. We also present theoretical predictions based on the single-impurity Anderson model using an extended non-crossing approximation (NCA), including all spin-orbit and crystal field splittings of the 4f states. The excellent agreement between theory and experiment provides strong evidence that the spectral properties of CeCu$_2$Si$_2$ can be described by single-impurity Kondo physics down to $T \approx 5$ K.Comment: 4 pages, 3 figure

Homozygous carriers of the TCF7L2 rs7903146 T-allele show altered postprandial response in triglycerides and triglyceride-rich lipoproteins

The TCF7L2 rs7903146 T-allele shows the strongest association with type 2 diabetes (T2D) among common gene variants. The aim of this study was to assess circulating levels of metabolites following a meal test in individuals carrying the high risk rs790346 TT genotype (cases) and low-risk CC genotype (controls). Sixty-two men were recruited based on TCF7L2 genotype, 31 were TT carriers and 31 were age- and BMI-matched CC carriers. All participants consumed a test meal after 12 hours of fasting. Metabolites were measured using proton nuclear magnetic resonance (NMR) spectroscopy. Metabolomic profiling of TCF7L2 carriers were performed for 141 lipid estimates. TT carriers had lower fasting levels of L-VLDL-L (total lipids in large very low density lipoproteins, p = 0.045), L-VLDL-CE (cholesterol esters in large VLDL, p = 0.03), and L-VLDL-C (total cholesterol in large VLDL, p = 0.045) compared to CC carriers. Additionally, TT carriers had lower postprandial levels of total triglycerides (TG) (q = 0.03), VLDL-TG (q = 0.05, including medium, small and extra small, q = 0.048, q = 0.0009, q = 0.04, respectively), HDL-TG (triglycerides in high density lipoproteins q = 0.037) and S-HDL-TG (q = 0.00003). In conclusion, TT carriers show altered postprandial triglyceride response, mainly influencing VLDL and HDL subclasses suggesting a genotype-mediated effect on hepatic lipid regulation