969 resultados para Production du savoir


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Few studies to date have examined age-related changes in markers of immune status in healthy older individuals. The immune status of 93 healthy individuals aged 55–70 years was assessed by two- and three-color flow cytometry and biochemical analysis. There were significant age effects (p ≤.05) on monocyte phagocytic activity and cluster of differentiation (CD) 3/human leukocyte antigen-D-related (HLA-DR) late-activated T lymphocytes (% expression). There was a significant (p ≤ 0.1) Age x Sex interaction in absolute counts (x 109/L) of CD3/CD8 total cytotoxic T lymphocytes (CTL), the CD4 T- helper to CD8 CTL ratio, the CD3/CD4/CD45RA naïve T helper to CD3/CD4/CD45RO memory T helper lymphocyte ratio, and interleukin (IL)-1ß (% expression) by activated monocytes. The study shows that alterations in markers of immune status occur between 55 and 70 years, and provides reference values for the lymphocyte measures in healthy men and postmenopausal women in this age group. The study further highlights the need for sex-specific reference ranges for such markers.

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Aspergillus niger MTCC 1344 was used to produce extracellular naringinase in a complex (molasses, yeast extract and salts) medium. An initial medium pH 4.5 and cultivation temperature 30 °C were optimal for enzyme production. Among various carbon and organic nitrogen sources used, molasses and peptone were the most effective for enzyme yield. The rate of enzyme production was enhanced when metal ions were added to the medium. Fermentation conditions are described which produced a higher rate of enzyme synthesis. An increase in initial sugar concentration from 6 to 10 g l−1 in the fermentation medium produced decreased naringinase synthesis while cell mass growth increased with the increase of sugar concentration. At a higher sugar level (10 g l−1) the production of cell mass decreased.

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Extracellular exoinulinase from Kluyveromyces marxianus YS-1, which hydrolyzes inulin into fructose, was immobilized on Duolite A568 after partial puriWcation by ethanol precipitation and gel exclusion chromatography on Sephadex G-100. Optimum temperature of immobilized enzyme was 55 °C, which was 5 °C higher than the free enzyme and optimal pH was 5.5. Immobilized biocatalyst retained more than 90% of its original activity after incubation at 60 °C for 3 h, whereas in free form its activity was reduced to 10% under same conditions, showing a signiWcant improvement in the thermal stability of the biocatalyst after immobilization. Apparent Km values for inulin, raYnose and sucrose were found to be 3.75, 28.5 and 30.7 mM, respectively. Activation energy (Ea) of the immobilized biocatalyst was found to be 46.8 kJ/mol. Metal ions like Co2+ and Mn2+ enhanced the activity, whereas Hg2+ and Ag2+ were found to be potent inhibitors even at lower concentrations of 1 mM. Immobilized biocatalyst was eVectively used in batch preparation of high fructose syrup from Asparagus racemosus raw inulin and pure inulin, which
yielded 39.2 and 40.2 g/L of fructose in 4 h; it was 85.5 and 92.6% of total reducing sugars produced, respectively.

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Response surface methodology was used to optimize the fermentation medium for enhancing naringinase production by Staphylococcus xylosus. The first step of this process involved the individual adjustment and optimization of various medium components at shake flask level. Sources of carbon (sucrose) and nitrogen (sodium nitrate), as well as an inducer (naringin) and pH levels were all found to be the important factors significantly affecting naringinase production. In the second step, a 22 full factorial central composite design was applied to determine the optimal levels of each of the significant variables. A second-order polynomial was derived by multiple regression analysis on the experimental data. Using this methodology, the optimum values for the critical components were obtained as follows: sucrose, 10.0%; sodium nitrate, 10.0%; pH 5.6; biomass concentration, 1.58%; and naringin, 0.50% (w/v), respectively. Under optimal conditions, the experimental naringinase production was 8.45 U/mL. The determination coefficients (R 2) were 0.9908 and 0.9950 for naringinase activity and biomass production, respectively, indicating an adequate degree of reliability in the model.

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After describing and analysing the purpose and shape of structural reform in Australia, the author uses the data gained from interviews with 16 South Australian women principals, to examine its effects on the work of principals. She uses her analysis to issue some warnings about the current moves to Local School Management in South Australia

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A newly isolated strain of Kluyveromyces marxianus YS-1 was used for the production of extra cellular inulinase in a medium containing inulin, meat extract, CaCl2 and sodium dodecyl sulphate (SDS). Fermentation medium pH 6.5, cultivation temperature 30 °C and 5% (v/v) inoculum of 12 h-old culture were optimal for enzyme production (30.8 IU/ml) with a fermentation time of 72 h at shake flask level. Raw inulin (2%, w/v) extracted from dahlia tubers by processing at 15 kg/cm2 for 10 min was optimum for bioreactor studies. Maximum enzyme production (55.4 IU/ml) was obtained at an agitation rate of 200 rpm and aeration of 0.75 vvm in a stirred tank reactor with a fermentation time of 60 h.

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Roots of Asparagus racemosus were used as a source of inulin for the production of inulinase from Kluyveromyces marxianus YS-1. Root extract prepared at 10 kg/cm2 for 10 min showed the maximum production of inulinase. Various parameters of fermentation have been examined in order to improve overall enzyme yield. Inulinase yield of 40.5 IU/mL in an optimized medium containing inulin (3.5%), beef extract (0.5%), MnSO4 (0.5 mM), CoCl2 (0.05 mM), SDS (0.4 mM) and pH 6.5 at 30 °C under agitation (150 rpm) for 60 h has been obtained at shake flask level. After optimization the enzyme production has been increased 6.1 times at flask level. In a bioreactor (working volume 1 L) fermentation medium containing 4% inulin has shown maximum inulinase production (47.3 IU/mL) under optimized parameters of 200 rpm, 0.75 vvm aeration at 30 °C after 60 h.

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In order to provide an alternative to traditional liquid fish oil gelatin capsules, we developed a solid, powdered form of omega-3 fish oil concentrate by forming calcium- and magnesium-fatty acid salts. These salts were produced using a concentrated fish oil ethyl ester that contained in excess of 60% omega-3 fatty acids. The bioavailability of these omega-3 salts was compared with that of fish oil ethyl ester in mice. Animals were given 8 mg of omega-3 fatty acid ethyl ester concentrate (control), calcium- or magnesium-omega-3 salts daily for three weeks. The omega-3 salt products resulted in omega-3 fatty acid content in serum and red blood cell membranes comparable to that produced by the ethyl ester supplementation. In addition, fecal excretion of omega-3 fatty acids was not increased by the presence of calcium or magnesium. In fact, there was a tendency for less omega-3 fatty acids to be excreted.

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In this paper, I will draw on the work of Julia Kristeva to argue that performativity can be understood in terms of a materialist ontology that underpins creative production and the knowing subject. To understand this, we need to examine the relationship between individual history, biology and culture and processes through which creative practice attributes value by translating psychic representations of affect and drive into verbal and visual signs. Kristeva's aesthetics does not plunge us into an obscure metaphysics, but provides a model for articulating material-discursive practices that emerge from corporeal responses. Enactments, predicated by desire give rise to agency and judgement allowing practice to test theory through the production of situated knowledge.

Kristeva's psychoanalytical position reveals the necessity of linking material and individual practices of art with the social through language and interpretation. Material-discursive practices can only acquire meaning through their relationship between the speaking subject and addressees. Art itself provides us with the means for discovering the knowledge it produces. In and through material practice, the work of art is capable of transferring back to the artist as viewer, structures of meaning that have hitherto been hidden. In practice, this involves a constant movement between the biological self (the self as 'other') and the social self, the ego. In artistic research, it can be said that the first addressee is the artist her/himself, as social other. Constant movement between the two in creative practice can thus be understood as a performative production of knowledge.

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This paper reports on the social learning from a project aimed to increase the knowledge and capacity of a group of farmers in Tasmania, Australia, to reduce the impacts of intensive agriculture on soil health and waterways, and to optimise the efficient use of on-farm inputs. The plan-do-check-review cycle adopted in this project required the farmers to assess current management practices, identify where to make changes, implement changes and monitor for improvements. The success of the project was due to careful attention to social processes as well as technical input. The combination of group activities with individual mentoring and one-to-one advice was key to the success of this project in enabling farmers to undertake on-farm action.

There is value in social learning that included developing relationships, using one-to-one contact and group workshops together with expert input when working with farmers to tackle some difficult and complex interrelated natural resource management and production issues. Sufficient time must be allowed for the process of facilitating good practice in natural resource management, particularly when addressing systemic environmental impacts. Practical operational recommendations are presented on communication, feedback, focus of activities and meeting content, as these will be useful to other project officers and facilitators working with farmer groups.

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Aquaculture is seen as an alternative to meeting the widening gap in global rising demand and decreasing supply for aquatic food products. Asia, the epicenter of the global aquaculture industry, accounts for over 90% of the global aquaculture production quantity and about 80% of the value. Asian aquaculture, as with global aquaculture, is dependent to a significant extent on alien species, as is the case for all the major food crops and husbanded terrestrial animals. However, voluntary and or accidental introduction of exotic aquatic species (alien species) is known to negatively impact local biodiversity. In this relatively young food production industry, mitigating the dependence on alien species, and thereby minimizing potential negative impacts on biodiversity, is an imperative for a sustainable future. In this context an attempt is made in this synthesis to understand such phenomena, especially with reference to Asian inland finfish, the mainstay of global aquaculture production. It is pointed out that there is potential for aquaculture, which is becoming an increasingly important food production process, not to follow the past path of terrestrial food crops and husbanded animals in regard to their negative influences on biodiversity.

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Environmental crises around the world have inspired an outpour of creative response. As the effects of climate change increasingly manifest, environmental! art is being politically and pedagogically mobilised for ameliorative strategies. The rubric that instrumentalist, techno-scientific approaches to environmental stress (and attendant social distress) cannot solely provide solutions to this challenge has found increasing acceptance. The concern of this paper, however, is the limited understanding of public art's capacity that is perpetuated bv certain trends in environmental art in which the work is charged with communicative responsibility,. Connected to the representational and instructive traditions of public art, this tendency is further informed by the influence of the 'information-deficit model' in environmental conmunication research: a concept that asserts a straightforward connection between information provision, indiyidual awareness and collective action on a concern. The idea that public art can function as a conduit for knowledge,.which in turn will inspire new moral positions and behaviours, absents the art work from the process of knowledge-making and the production of conditons that enable new practice. Arguing for a revised approach to the environmental possibilities of public art, this paper will propose that in thinking aboutl environmental transformation as essentially unrepresentable, a dfferent mode of public engagement with the issue is enabled.

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