52 research outputs found
Efficacité énergétique et émissions de GES de systèmes d'élevage bovin viande en Amazonie.
L?élevage au Brésil, 1er exportateur mondial de viande, serait responsable de plus de 75% des déforestations et 19% des émissions nationales de gaz à effet de serre (GES). L?objectif de notre étude est de mettre au point une première méthode de calcul d?efficacité énergétique et d?émissions de GES des systèmes d?élevage amazoniens, en se basant sur la méthode Planète. Une révision de l?ensemble des coefficients énergétiques et des facteurs d?émission de GES ainsi que l?ajout de certaines rubriques ont permis d?élaborer un logiciel de calcul adapté au contexte régional. Six systèmes d?élevage bovin allaitants ont été étudiés lors d?enquêtes directes : un naisseur, trois engraisseurs et deux naisseurs-engraisseurs avec des troupeaux compris entre 650 et 3700 têtes, des charges instantanées variables, liées à des gestions de pâturage et des pratiques alimentaires très diversifiées. Les consommations d?énergie sont en moyenne de 9 724 MJ/t poids vif/an (min=4 019 MJ/t, max=15 243 MJ/t). Les principaux postes, responsables de 56% à 93% des consommations d?énergie, sont les achats d?aliments, la fertilisation des pâturages et l?achat de carburant (et d?animaux pour les engraisseurs). Ces systèmes d?élevage basés sur des ressources herbagères abondantes, utilisant peu d?intrants et d?infrastructures sont peu consommateurs d?énergie, comparés aux autres systèmes dans le monde. Les différences d?efficacité énergétique sont liées à l?efficacité productive végétale et animale et non au degré d?intensité d?utilisation des intrants. Les émissions de GES sont importantes, en moyenne de 19,8 t eq CO2/ t poids vif/ an (min= 11,2 t eq CO2/t, max= 40,5 t eq CO2/t). La déforestation avec un amortissement linéaire sur 20 ans représente de zéro jusqu?à 75% des émissions totales. Nous avons aussi montré l?intérêt environnemental de systèmes productifs intégrant agriculture et élevage. Ces résultats à l?échelle des exploitations participent de la prise de conscience individuelle des éleveurs et renforcent les engagements locaux pour la « déforestation zéro ». La comparaison avec d?autres systèmes d?élevage dans le monde souligne l?intérêt d?une production animale maitrisée, en matière de déforestation et d?intensification, sous les tropiques humides. Plus largement cette étude montre la validité de cette méthode et devrait permettre de généraliser ces bilans
Acetate intolerance is mediated by enhanced synthesis of nitric oxide by endothelial cells.
The clinical picture of acetate intolerance strictly mimics the nitric oxide (NO) effect, including smooth muscle relaxation and extreme vasodilation. Because acetate induces production of cAMP, which is a powerful stimulus of NO synthase (NOS), we evaluated the effect of different dialysate solutions with and without acetate on NOS activity in endothelial cells (EC). NOS activity of EC, evaluated as H3-citrulline produced from H3-arginine, was modulated by the dialysate composition (e.g., 38 mmol/L acetate produced an increase of 3.2 +/- 0.39-fold compared with basal values (P < 0.0005), and the small amount of acetate (4 mmol/L) in 35 mmol/L bicarbonate solution increased the NOS activity by 2 +/- 0.49-fold (P < 0.05). Conversely, the acetate-free solution produced no effect on NOS activity. The mRNA encoding for inducible NOS was highly expressed in EC incubated with acetate buffer and also with acetate in bicarbonate dialysis buffer. The EC proliferative index was depressed by acetate (P < 0.0005), and tumor necrosis factor synthesis was increased (P < 0.0005) compared with acetate-free buffer. This study suggests that dialytic "acetate intolerance" can be induced by the activation, through cAMP and tumor necrosis factor release, of NOS. The small amount of acetate in bicarbonate dialysate, although capable of inducing in vitro NOS activation, is likely to be rapidly metabolized, whereas the large amounts of this anion in acetate fluids overwhelm metabolism by the liver. Acetate-free dialysate is the only solution that provides an acceptable level of biocompatibility both in vivo and in vitro
Patterns of amenable child mortality over time in 34 member countries of the Organisation for Economic Co-operation and Development (OECD): Evidence from a 15-year time trend analysis (2001-2015)
Objectives To analyse the trends of amenable mortality rates (AMRs) in children over the period 2001-2015. Design Time trend analysis. Setting Thirty-four member countries of the Organisation for Economic Co-operation and Development (OECD). Participants Midyear estimates of the resident population aged 6414 years. Primary and secondary outcome measures Using data from the WHO Mortality Database and Nolte and McKee's list, AMRs were calculated as the annual number of deaths over the population/100 000 inhabitants. The rates were stratified by age groups (<1, 1-4, 5-9 and 10-14 years). All data were summarised by presenting the average rates for the years 2001/2005, 2006/2010 and 2011/2015. Results There was a significant decline in children's AMRs in the <1 year group in all 34 OECD countries from 2001/2005 to 2006/2010 (332.78 to 295.17/100 000; %\u394-11.30%; 95% CI -18.75% to -3.85%) and from 2006/2010 to 2011/2015 (295.17 to 240.22/100 000; %\u394-18.62%; 95% CI -26.53% to -10.70%) and a slow decline in the other age classes. The only cause of death that was significantly reduced was conditions originating in the early neonatal period for the <1 year group. The age-specific distribution of causes of death did not vary significantly over the study period. Conclusions The low decline in amenable mortality rates for children aged 651 year, the large variation in amenable mortality rates across countries and the insufficient success in reducing mortality from all causes suggest that the heath system should increase its efforts to enhance child survival. Promoting models of comanagement between primary care and subspecialty services, encouraging high-quality healthcare and knowledge, financing universal access to healthcare and adopting best practice guidelines might help reduce amenable child mortality
HyperProbe consortium: innovate tumour neurosurgery with innovative photonic solutions
Recent advancements in imaging technologies (MRI, PET, CT, among others) have significantly improved clinical localisation of lesions of the central nervous system (CNS) before surgery, making possible for neurosurgeons to plan and navigate away from functional brain locations when removing tumours, such as gliomas. However, neuronavigation in the surgical management of brain tumours remains a significant challenge, due to the inability to maintain accurate spatial information of pathological and healthy locations intraoperatively. To answer this challenge, the HyperProbe consortium have been put together, consisting of a team of engineers, physicists, data scientists and neurosurgeons, to develop an innovative, all-optical, intraoperative imaging system based on (i) hyperspectral imaging (HSI) for rapid, multiwavelength spectral acquisition, and (ii) artificial intelligence (AI) for image reconstruction, morpho-chemical characterisation and molecular fingerprint recognition. Our HyperProbe system will (1) map, monitor and quantify biomolecules of interest in cerebral physiology; (2) be handheld, cost-effective and user-friendly; (3) apply AI-based methods for the reconstruction of the hyperspectral images, the analysis of the spatio-spectral data and the development and quantification of novel biomarkers for identification of glioma and differentiation from functional brain tissue. HyperProbe will be validated and optimised with studies in optical phantoms, in vivo against gold standard modalities in neuronavigational imaging, and finally we will provide proof of principle of its performances during routine brain tumour surgery on patients. HyperProbe aims at providing functional and structural information on biomarkers of interest that is currently missing during neuro-oncological interventions
The stimulatory effect of male agouti (Dasyprocta prymnolopha) on the onset of female puberty
Monitoramento do ciclo estral de cutias (Dasyprocta leporina Lichtenstein, 1823) através de citologia esfoliativa vaginal e ultrassonografia
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