999 resultados para adaptation professionnelle


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This study examined adaptation decisions of village tank farmers in Sri Lanka, focusing on how commonly held beliefs on local rainfall influence their adaptation choices. Findings suggest that farmers’ have shared beliefs consistent with local pattern of rainfall variability that help to explain short-, medium- and long-term decisions of adaptation.

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Australian agriculture is very susceptible to the adverse impacts of climate change, with major shifts in temperature and rainfall projected. In this context, this paper describes a research methodology for assessing potential climate change impacts on, and formulating adaptation options for, agriculture at regional level. The methodology was developed and applied in the analysis of climate change impacts on key horticultural commodities—pome fruits (apples and pears), stone fruits (peaches and nectarines) and wine grapes—in the Goulburn Broken catchment management region, State of Victoria, Australia. Core components of the methodology are mathematical models that enable to spatially represent the degree of biophysical land suitability for the growth of agricultural commodities in the region of interest given current and future climatic conditions. The methodology provides a sound analytic approach to 1) recognise regions under threat of declines in agricultural production due to unfolding climatic changes; 2) identify alternative agricultural systems better adapted to likely future climatic conditions and 3) investigate incremental and transformational adaptation actions to improve the problem situations that are being created by climate change.

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A decision-making framework was developed and applied in regional Australia to identify adaptation issues arising in agricultural systems and rural production as a consequence of climate change. Australian agriculture is very susceptible to the adverse impacts of climate change, with major shifts in temperature and rainfall projected. An advantage of the framework is that it provides a suite of tools to aid in the formulation of strategies for sustainable regional development and adaptation. The decision-making framework uses a participatory approach that integrates land suitability analysis with uncertainty analysis and spatial optimisation to determine optimal agricultural land use (at a regional scale) for current and possible future climatic conditions. It thus provides a robust analytic approach to (i) recognise regions under threat of productivity declines, (ii) identify alternative cropping systems better adapted to likely future climatic conditions and (iii) investigate policy actions to improve the sub-optimal situations created by climate change. The decision-making framework and its methods were applied in a case study of the South West Region of Victoria.

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Contrast detection is commonly measured clinically; however, discrimination between contrasts is also important for natural vision. Furthermore, optimal performance requires the visual system to adapt to ambient contrast conditions. Recent studies of primate neurophysiology demonstrate significant retinal involvement in contrast adaptation. This study was conducted to investigate whether glaucoma alters contrast adaptation. Both detection and discrimination task performance were examined.

Methods:
Psychophysical contrast detection and discrimination thresholds were measured in central vision, for a vertically oriented D6 centered on 3 cyc/deg. Thresholds were measured with and without adaptation to low (15%)- and high (70%)-contrast, vertically oriented, 3-cyc/deg sinusoidal gratings. Fifteen people with glaucoma, and 15 age-similar control subjects participated. Full-contrast discrimination (dipper) functions were measured for a subset (three patients with glaucoma and three control subjects).

Results:
On average, the glaucoma group showed elevated detection and discrimination thresholds relative to control subjects (detection: t(28) = 2.42; P = 0.02; discrimination: F1,28 = 6.157, P = 0.02). For the subset of additionally tested participants, normalized contrast discrimination functions were similarly shaped for all observers. Glaucoma group thresholds were less influenced by contrast adaptation than were control subjects, for discrimination (F1,28 = 10.89, P < 0.01) but not detection (F1,28 = 2.28; P = 0.11). Differences between groups were greatest for low-contrast stimuli (significant interaction between contrast and group: P < 0.01).

Conclusions:
Glaucoma alters the effect of contrast adaptation on discrimination performance, particularly at low contrast. The study of suprathreshold aspects of vision may reveal new insights into the pathophysiology of glaucoma and possibly relate better to real-world visual performance than detection measures.

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Content adaptation is used to adapt multimedia content to a version required by users. In the service-oriented scheme, adaptation functions are provided as services by third-party service providers. Clients pay for the consumed services and thus demand service quality. Providers advertise their services; each with varied quality-of-services (QoS). Some of these QoS however, may not be deliverable accordingly during the actual service execution due to heavy load. Thus, the provider should able to determine a current deliverable QoS before the service level agreement (SLA) is settled with the requesters. In this paper, we propose a strategy for service providers to evaluate incoming requests and capable of offering the new QoS to the requests potentially being initially rejected. The proposed strategy takes into account the current server load and requests' priority. We analysed the performance of the proposed strategy in terms of SLA settlement under various conditions. The results indicate that the proposed strategy performs well. © 2014 IEEE.

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Skeletal muscles contain several subtypes of myofibers that differ in contractile and metabolic properties. Transcriptional control of fiber-type specification and adaptation has been intensively investigated over the past several decades. Recently, microRNA (miRNA)-mediated posttranscriptional gene regulation has attracted increasing attention. MiR-23a targets key molecules regulating contractile and metabolic properties of skeletal muscle, such as myosin heavy-chains and peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1α). In the present study, we analyzed the skeletal muscle phenotype of miR-23a transgenic (miR-23a Tg) mice to explore whether forced expression of miR-23a affects markers of mitochondrial content, muscle fiber composition, and muscle adaptations induced by 4 weeks of voluntary wheel running. When compared with wild-type mice, protein markers of mitochondrial content, including PGC-1α, and cytochrome c oxidase complex IV (COX IV), were significantly decreased in the slow soleus muscle, but not the fast plantaris muscle of miR-23a Tg mice. There was a decrease in type IId/x fibers only in the soleus muscle of the Tg mice. Following 4 weeks of voluntary wheel running, there was no difference in the endurance exercise capacity as well as in several muscle adaptive responses including an increase in muscle mass, capillary density, or the protein content of myosin heavy-chain IIa, PGC-1α, COX IV, and cytochrome c. These results show that miR-23a targets PGC-1α and regulates basal metabolic properties of slow but not fast twitch muscles. Elevated levels of miR-23a did not impact on whole body endurance capacity or exercise-induced muscle adaptations in the fast plantaris muscle.

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BACKGROUND: Pregnancy induces adaptations in maternal metabolism to meet the increased need for nutrients by the placenta and fetus. Creatine is an important intracellular metabolite obtained from the diet and also synthesised endogenously. Experimental evidence suggests that the fetus relies on a maternal supply of creatine for much of gestation. However, the impact of pregnancy on maternal creatine homeostasis is unclear. We hypothesise that alteration of maternal creatine homeostasis occurs during pregnancy to ensure adequate levels of this essential substrate are available for maternal tissues, the placenta and fetus. This study aimed to describe maternal creatine homeostasis from mid to late gestation in the precocial spiny mouse. METHODS: Plasma creatine concentration and urinary excretion were measured from mid to late gestation in pregnant (n = 8) and age-matched virgin female spiny mice (n = 6). At term, body composition and organ weights were assessed and tissue total creatine content determined. mRNA expression of the creatine synthesising enzymes arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT), and the creatine transporter (CrT1) were assessed by RT-qPCR. Protein expression of AGAT and GAMT was also assessed by western blot analysis. RESULTS: Plasma creatine and renal creatine excretion decreased significantly from mid to late gestation (P < 0.001, P < 0.05, respectively). Pregnancy resulted in increased lean tissue (P < 0.01), kidney (P < 0.01), liver (P < 0.01) and heart (P < 0.05) mass at term. CrT1 expression was increased in the heart (P < 0.05) and skeletal muscle (P < 0.05) at term compared to non-pregnant tissues, and creatine content of the heart (P < 0.05) and kidney (P < 0.001) were also increased at this time. CrT1 mRNA expression was down-regulated in the liver (<0.01) and brain (<0.01) of pregnant spiny mice at term. Renal AGAT mRNA (P < 0.01) and protein (P < 0.05) expression were both significantly up-regulated at term, with decreased expression of AGAT mRNA (<0.01) and GAMT protein (<0.05) observed in the term pregnant heart. Brain AGAT (<0.01) and GAMT (<0.001) mRNA expression were also decreased at term. CONCLUSION: Change of maternal creatine status (increased creatine synthesis and reduced creatine excretion) may be a necessary adjustment of maternal physiology to pregnancy to meet the metabolic demands of maternal tissues, the placenta and developing fetus.