137 research outputs found

    Assessing the agro-environmental sustainability of organic mixed-crop dairy systems on the basis of a multivariate approach

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    Sustainable development calls upon the farming sector to commit itself to the transmission of natural resources to future generations. The INRA research team of Mirecourt studies the design of environmentally-friendly farming systems. The design of these systems is based on a multitude of objectives, and their evaluation is determined by a wide range of criteria. This work aims at determining the practical conditions for implementing agricultural systems considered to be sustainable from an environmental point of view. Two organic dairy systems considered to be environmentally friendly ex ante have been designed in partnership with the staff of the INRA research team of Mirecourt. A grazing dairy system and a mixed-crop dairy system are being experimentally tested at the system scale. The two systems have environmental and agricultural objectives. They are managed using multi-objective decision rules and are assessed on their biotechnical and practical properties, using a structured multiyear experimental design, completed by a model-based assessment. Assessment is oriented towards progressive and permanent re-designing of the systems in order to increase their environmental sustainability and feasibility at the practical level. Knowledge acquired from the two prototypes will then have to be validated on commercial farms

    Cultural Orientations of sport managers

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    Various interpretations of sport management are cultural constructs underpinned by core assumptions and values held by members of professional communities. Sport managers world wide share common problems, but differ in how they resolve them. These universal differences emerge from the relationships they form with other people, and their attitude to time, activities and the natural environment. This paper examines the role of sport managers’ cultural orientations in the interpretation and practice of sport management. Using a multiple dimension model (Hampden-Turner and Trompenaars, 2000) it sketches the cultural profiles of fifteen sport managers from seven countries. A combination of methods was employed including questionnaires, interviews and participant observation. It is contended that the culture of sport management concerns a social process by which managers get involved in reconciling seven fundamental cultural dilemmas in order to perform tasks and achieve certain ends. Thus, a knowledge of the cultural meaning of sport management in a particular country would equip sport managers with a valuable tool in managing both the cultural diversity of their own work forces and in developing appropriate cross-cultural skills needed for running international events, marketing campaigns, sponsorship deals and joint ventures

    Heterogeneity of hypothalamic pro-opiomelanocortin-expressing neurons revealed by single-cell RNA sequencing

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    Objective\textbf{Objective} Arcuate proopiomelanocortin (POMC) neurons are critical nodes in the control of body weight. Often characterized simply as direct targets for leptin, recent data suggest a more complex architecture. Methods\textbf{Methods} Using single cell RNA sequencing, we have generated an atlas of gene expression in murine POMC neurons. Results\textbf{Results} Of 163 neurons, 118 expressed high levels of Pomc\textit{Pomc} with little/no Agrp expression and were considered “canonical” POMC neurons (P+^{+}). The other 45/163 expressed low levels of Pomc\textit{Pomc} and high levels of Agrp\textit{Agrp} (A+^{+}P+_{+}). Unbiased clustering analysis of P+^{+} neurons revealed four different classes, each with distinct cell surface receptor gene expression profiles. Further, only 12% (14/118) of P+^{+} neurons expressed the leptin receptor (Lepr\textit{Lepr}) compared with 58% (26/45) of A+^{+}P+_{+} neurons. In contrast, the insulin receptor (Insr\textit{Insr}) was expressed at similar frequency on P+^{+} and A+^{+}P+_{+} neurons (64% and 55%, respectively). Conclusion\textbf{Conclusion} These data reveal arcuate POMC neurons to be a highly heterogeneous population. Accession Numbers: GSE92707.This work was supported by the UK Medical Research Council (MRC) Metabolic Disease Unit (MRC_MC_UU_12012/1 & MRC_MC_UU_12012/5), a Wellcome Trust Strategic Award (100574/Z/12/Z), and the Helmholtz Alliance ICEMED

    mTORC1 in AGRP neurons integrates exteroceptive and interoceptive food-related cues in the modulation of adaptive energy expenditure in mice

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    Energy dissipation through interscapular brown adipose tissue (iBAT) thermogenesis is an important contributor to adaptive energy expenditure. However, it remains unresolved how acute and chronic changes in energy availability are detected by the brain to adjust iBAT activity and maintain energy homeostasis. Here, we provide evidence that AGRP inhibitory tone to iBAT represents an energy-sparing circuit that integrates environmental food cues and internal signals of energy availability. We establish a role for the nutrient-sensing mTORC1 signaling pathway within AGRP neurons in the detection of environmental food cues and internal signals of energy availability, and in the bi-directional control of iBAT thermogenesis during nutrient deficiency and excess. Collectively, our findings provide insights into how mTORC1 signaling within AGRP neurons surveys energy availability to engage iBAT thermogenesis, and identify AGRP neurons as a neuronal substrate for the coordination of energy intake and adaptive expenditure under varying physiological and environmental contexts.This work was supported by the Medical Research Council New Blood Fellowship [MR/M501736/1] to CB, a NIDDK K99/R00 award to CB, the Medical Research Council Metabolic Disease Unit programme grant, the Disease Model Core facilities, and the Wellcome Trust Cambridge Mouse Biochemistry Laboratory. Animal procedures were performed under Tony Coll’s home office PPL 80/2497 and Toni Vidal-Puig PPL 80/2484

    Lipid-Induced Peroxidation in the Intestine Is Involved in Glucose Homeostasis Imbalance in Mice

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    BACKGROUND: Daily variations in lipid concentrations in both gut lumen and blood are detected by specific sensors located in the gastrointestinal tract and in specialized central areas. Deregulation of the lipid sensors could be partly involved in the dysfunction of glucose homeostasis. The study aimed at comparing the effect of Medialipid (ML) overload on insulin secretion and sensitivity when administered either through the intestine or the carotid artery in mice. METHODOLOGY/PRINCIPAL FINDINGS: An indwelling intragastric or intracarotid catheter was installed in mice and ML or an isocaloric solution was infused over 24 hours. Glucose and insulin tolerance and vagus nerve activity were assessed. Some mice were treated daily for one week with the anti-lipid peroxidation agent aminoguanidine prior to the infusions and tests. The intestinal but not the intracarotid infusion of ML led to glucose and insulin intolerance when compared with controls. The intestinal ML overload induced lipid accumulation and increased lipid peroxidation as assessed by increased malondialdehyde production within both jejunum and duodenum. These effects were associated with the concomitant deregulation of vagus nerve. Administration of aminoguanidine protected against the effects of lipid overload and normalized glucose homeostasis and vagus nerve activity. CONCLUSIONS/SIGNIFICANCE: Lipid overload within the intestine led to deregulation of gastrointestinal lipid sensing that in turn impaired glucose homeostasis through changes in autonomic nervous system activity

    Hypoxia-Inducible Factor Directs POMC Gene to Mediate Hypothalamic Glucose Sensing and Energy Balance Regulation

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    Hypoxia-inducible factor (HIF) is a nuclear transcription factor that responds to environmental and pathological hypoxia to induce metabolic adaptation, vascular growth, and cell survival. Here we found that HIF subunits and HIF2α in particular were normally expressed in the mediobasal hypothalamus of mice. Hypothalamic HIF was up-regulated by glucose to mediate the feeding control of hypothalamic glucose sensing. Two underlying molecular pathways were identified, including suppression of PHDs by glucose metabolites to prevent HIF2α degradation and the recruitment of AMPK and mTOR/S6K to regulate HIF2α protein synthesis. HIF activation was found to directly control the transcription of POMC gene. Genetic approach was then employed to develop conditional knockout mice with HIF inhibition in POMC neurons, revealing that HIF loss-of-function in POMC neurons impaired hypothalamic glucose sensing and caused energy imbalance to promote obesity development. The metabolic effects of HIF in hypothalamic POMC neurons were independent of leptin signaling or pituitary ACTH pathway. Hypothalamic gene delivery of HIF counteracted overeating and obesity under conditions of nutritional excess. In conclusion, HIF controls hypothalamic POMC gene to direct the central nutrient sensing in regulation of energy and body weight balance
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