833 research outputs found

    Incorporation du coprah et des cuticules de cacao et d’arachide dans l’aliment du (tilapia du nil( (Oreohromis niloticus, linné, 1758) eleve en etang : Effet sur la croissance et la composition biochimique

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    Dans le but de réduire le coût de l’alimentation du tilapia en élevage, quatre aliments exogènes pulvérulents dont un industriel (Ivograin) servant de référence (AR) et trois tests locaux (A1, A2 et A3) formulés uniquement à base de sous-produits locaux ont été utilisés. La composition de base des aliments tests est : A1 (cuticules de de fève de cacao, son de maïs, tourteaux de soja et coton) ; A2 (cuticules de graine d’arachide, son de maïs, tourteaux de soja et coton) et A3 (tourteaux de coprah, soja et coton et son de maïs). Tous les aliments titrent environ 28 % de protéines. L’expérience est conduite à la ferme « Blondey » (Côte d’Ivoire) sur des juvéniles de Oreochromis niloticus d’un poids initial de 33,3 ± 0,4 g. Des juvéniles ne recevant pas d’aliment exogène ont servi de lot témoin (At) pour apprécier l’effet de l’aliment endogène. La densité de stockage était de 2 poissons/m2. Trois étangs par traitement ont été utilisés. La ration journalière a été distribuée à 9 h et à 15 h. Après 180 jours d’expérience, les poids moyens finaux ont atteint des valeurs respectives de 273,42 ± 26g ; 295,08 ± 18,5 g ; 352,1 ± 20,7g ; 309,38 ± 22,3 g et 101,06 ± 4 g pour A3, A2, A1, AR et At. Au niveau des aliments exogènes, le meilleur quotient nutritif (Qn= 2,22) et de croissance journalière (1,77 g/jour) ont été obtenus avec A1. Le plus grand Qn (2,88) et la plus faible croissance journalière (1,33g /jour) sont enregistrés avec A3. La comparaison de tous les lots indique que la plus faible croissance (0,38 g/jour) est enregistrée chez les poissons non nourris à l’aliment exogène (At). Les lipides corporels (16 - 17 %) sont plus élevés chez les poissons nourris aux aliments tests que ceux des lots de référence (14 %) et témoins (13 %). Par rapport à l’aliment AR, les aliments tests réduisent le coût de revient de l’aliment et le coût de l’alimentation par unité de prise de poids de 15 - 18 % et 3,1 - 27,4 %, respectivement.Mots clés : Aliments, arachide, cacao, coprah, cuticules, Oreochromis niloticusEnglish AbstractIncorporation of coconut oil cake, cocoa bean shell and peanut skin in diet for nile tilapia (Oreohromis niloticus, linné, 1758) reared in pond : Effect on growth and biochemical compositionIn order to reduce feeding cost of rearing tilapia, four powdered diets including an industrial product (Ivograin) (as reference = AR) and three practical diets (A1, A2 and A3) formulated using local by-products were used. Formulated diets were designated as A1 (cocoa bean shell, corn bran, soybean oil cake, cottonseeds oil cake, premix), A2 (peanut skin, corn bran, soybean oil cake, cottonseeds oil cake, premix) and A3 (corn bran, soybean oil cake, cottonseeds oil cake and coconut oil cake). The four diets contained approximately 28 % crude protein. The experiment was carried out at farm « Blondey » (Ivory Coast) on fingerlings Oreochromis niloticus with an initial body weight of 33.3 ± 0.4g. In addition, fingerlings non-fed with exogenous diet were used as control group to assess the impact of the natural food. The used stocking density was 2 fish/m2. Three replicate ponds were assigned to each of the treatment. Fish were fed twice daily (9.00 h and 15.00 h). After 180 days of experiment, the final body weight observed were respectively 273.42 ± 26 ; 295.08 ± 18.5 ; 352.1 ± 20,7 ; 309.38 ± 22.3 g and 101.06 ± 4 g for A3, A2, A1, AR and At. Considering the four diets (A1, A2, A3 and AR), the best daily weight gain (1.77 g/day) and feed conversion ratio (2.22) were obtained with A1 which were significantly different (p < 0.05) from values obtained for the other groups. The poorest weight gain (1.33 g/day) and the highest feed conversion ratio (2.88) were recorded for A3. The comparison of all groups (A1, A2, A3, AR and At) revealed that the poorest value of the daily weight gain (1.33 g/day) was recorded for the control group (At). Fat deposition was highest (16 - 17 %) in fish fed practical diets, while fish fed diets AR and control fish (At) recorded respectively (14 %) and (13 %). Practical diets reduced the feed cost and feeding cost per unit of weight gain by 15 - 18 % and 3.1 - 27.4 %, respectively.Keywords : Diets, peanut skin, cocoa bean shell, coconut oil cake, Oreochromis niloticu

    Dietary docosahexaenoic acid supplementation modulates hippocampal development in the pemt-/- mouse

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    The development of fetal brain is influenced by nutrients such as docosahexaenoic acid (DHA, 22:6) and choline. Phosphatidylethanolamine-N-methyltransferase (PEMT) catalyzes the biosynthesis of phosphatidylcholine from phosphatidylethanolamine enriched in DHA and many humans have functional genetic polymorphisms in the PEMT gene. Previously, it was reported that Pemt-/- mice have altered hippocampal development. The present study explores whether abnormal phosphatidylcholine biosynthesis causes altered incorporation of DHA into membranes, thereby influencing brain development, and determines whether supplemental dietary DHA can reverse some of these changes. Pregnant C57BL/6 wild type (WT) and Pemt-/- mice were fed a control diet, or a diet supplemented with 3 g/kg of DHA, from gestational day 11 to 17. Brains from embryonic day 17 fetuses derived from Pemt-/- dams fed the control diet had 25-50% less phospholipid-DHA as compared with WT (p < 0.05). Also, they had 60% more neural progenitor cell proliferation (p < 0.05), 60% more neuronal apoptosis (p < 0.01), and 30% less calretinin expression (p < 0.05; a marker of neuronal differentiation) in the hippocampus compared with WT. The DHA-supplemented diet increased fetal brain Pemt-/- phospholipid-DHA to WT levels, and abrogated the neural progenitor cell proliferation and apoptosis differences. Although this diet did not change proliferation in the WT group, it halved the rate of apoptosis (p < 0.05). In both genotypes, the DHA-supplemented diet increased calretinin expression 2-fold (p < 0.05). These results suggest that the changes in hippocampal development in the Pemt-/- mouse could be mediated by altered DHA incorporation into membrane phospholipids, and that maternal dietary DHA can influence fetal brain development

    Highlights of the São Paulo ISEV workshop on extracellular vesicles in cross-kingdom communication

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    In the past years, extracellular vesicles (EVs) have become an important field of research since EVs have been found to play a central role in biological processes. In pathogens, EVs are involved in several events during the host–pathogen interaction, including invasion, immunomodulation, and pathology as well as parasite–parasite communication. In this report, we summarised the role of EVs in infections caused by viruses, bacteria, fungi, protozoa, and helminths based on the talks and discussions carried out during the International Society for Extracellular Vesicles (ISEV) workshop held in São Paulo (November, 2016), Brazil, entitled Cross-organism Communication by Extracellular Vesicles: Hosts, Microbes and Parasites. © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.11Ysciescopu

    Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

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    We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc

    Shrinking a large dataset to identify variables associated with increased risk of Plasmodium falciparum infection in Western Kenya

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    Large datasets are often not amenable to analysis using traditional single-step approaches. Here, our general objective was to apply imputation techniques, principal component analysis (PCA), elastic net and generalized linear models to a large dataset in a systematic approach to extract the most meaningful predictors for a health outcome. We extracted predictors for Plasmodium falciparum infection, from a large covariate dataset while facing limited numbers of observations, using data from the People, Animals, and their Zoonoses (PAZ) project to demonstrate these techniques: data collected from 415 homesteads in western Kenya, contained over 1500 variables that describe the health, environment, and social factors of the humans, livestock, and the homesteads in which they reside. The wide, sparse dataset was simplified to 42 predictors of P. falciparum malaria infection and wealth rankings were produced for all homesteads. The 42 predictors make biological sense and are supported by previous studies. This systematic data-mining approach we used would make many large datasets more manageable and informative for decision-making processes and health policy prioritization

    Global Search for New Physics with 2.0/fb at CDF

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    Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for "bumps" that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0/fb of ppbar collisions at sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D Rapid Communication

    Observation of Orbitally Excited B_s Mesons

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    We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

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    The elliptic, v2v_2, triangular, v3v_3, and quadrangular, v4v_4, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range η<0.8|\eta|<0.8 at different collision centralities and as a function of transverse momentum, pTp_{\rm T}, out to pT=20p_{\rm T}=20 GeV/cc. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for pT>8p_{\rm T}>8 GeV/cc. The small pTp_{\rm T} dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to pT=8p_{\rm T}=8 GeV/cc. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least pT=8p_{\rm T}=8 GeV/cc indicating that the particle type dependence persists out to high pTp_{\rm T}.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
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