934 resultados para Necessary optimality conditions of Euler-Lagrange type


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The presence of obesity with type 2 diabetes increases morbidity and mortality from each condition. Excess adiposity accentuates insulin resistance and complicates the treatment of type 2 diabetes. Glucagon-like peptide 1 receptor agonists promote weight loss, whereas metformin, dipeptidyl peptidase 4 inhibitors, and a glucosidase inhibitors are typically weight neutral. The anabolic effects of increased insulin secretion and action restrict the benefits of treatment in obese patients. New treatments should ideally reduce hyperglycaemia and excess adiposity. Potential new treatments include analogues of intestinal and adipocyte hormones, inhibitors of renal glucose reabsorption and cellular glucocorticoid activation, and activators of cellular energy production.

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The effects of antioxidants and stabilizers on the oxidative degradation of polyolefins (low density polyethylene [LDPE] and polypropylene [PPJ have been studied after subjecting to prior high temperature processing treatments. The changes in the both chemical and physical properties of unstabilized polymers occurring during processing were found to be strongly dependent on the amount of oxygen present in the mixer. Subsequent thermal and photo-oxidation showed very similar characteristics and the chromophore primarily responsible for:both thermo and photooxidative degradation of unstabilized polymers was found to be hydroperoxide formed during processing. Removal of hydroperoxide by heat treatment in an inert atmosphere although increasing ketonic carbonyl concentration, markedly decreased the rate of photo-oxidation, introducing an induction period similar to that of an unprocessed sample. It was concluded that hydroperoxides are the most important initiators in normally processed polymers during the early stages of photo-oxidation. Antioxidants such as metal dithiocarbamates which act by destroying peroxides into non-radica1 products were found to be efficient melt stabilizers for polyolefins and effective UV stabilizers during the initial photo-oxidation stage, whilst a phenolic antioxidant, n-octadecyl-3-(3',5'-di-terbutyl 4'hydroxypheny1) propionate (Irganox 1076) retarded photo-oxidation rate in the later stages. A typical 'UV absorber' 2-hydroxy-4-octyloxy-benzophenone (HOBP) has a minor thermal antioxidant action but retarded photo-oxidation at all stages. A substituated piperidine derivative, Bis [2.2.6.6-tetramethylpiperidlnyl-4] sebacate (Tinuvin 770) behaved as an pro-oxidant during thermal oxidation of polyolefins but was an effective stabilizer against UV light. The UV absorber, HOBP synergised effectively with both peroxide decomposing antioxidants (metal dithiocarbamates) and a chain-breaking antioxidant (Irganox 1076) during photo-oxidation of the poymers studed whereas the combined effect was additive during thermal oxidation. By contrast, the peroxide decornposers and chain-breaking antioxidant (Irganox 1076) which were effective synergists during thermal oxidation of LDPE· were antagonistic during photo-oxidation. The mechanisms of these processes are discussed.

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This thesis deals with the integration of the manpower criterion with the strategic decision making processes of technological projects in developing countries. This integration is to be achieved by ensuring the involvement of the actors, who have relevant roles and responsibilities along the whole life cycle of the project, in the strategic decision making phases of the project. The relevance of the actors is ascertained by the use of a responsibility index which relates their responsibility to the project's constituent stages. In the context of a technological project in a typical centrally-planned developing environment, the actors are identified as Arbiters, Planners, Implementors and Operators and their roles, concerns and objectives are derived. In this context, the actors are usually government and non-government organisations. Hence, decision making will involve multiple agencies as well as multiple criteria. A methodology covering the whole decision-making process, from options generation to options selection, and adopting Saaty's Analytical Hierarchy Process as an operational tool is proposed to deal with such multiple-criteria, multipleagency decision situations. The methodology is intended to integrate the consideration of the relevant criteria, the prevailing environmental and policy factors, and the concerns and objectives of the relevant actors into a unifying decision-making process which strives to facilitate enlightened decision making and to enhance learning and interaction. An extensive assessment of the methodology's feasibility, based on a specific technological project within the Iraqi oil industry is included, and indicates that the methodology should be both useful and implementable.

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The objective of this research was to investigate the effects of normal aging and the additional effects of chronic exposure to two experimental diets, one enriched in aluminium, the other enriched in lecithin, on aspects of the behaviour and brain histology of the female mouse. The aluminium diet was administered in an attempt to develop a rodent model of Dementia of the Alzheimer Type (DAT). With normal aging, almost all assessed aspects of behaviour were found to be impaired. As regards cognition, selective impairments of single-trial passive avoidance and Morris place learning were observed. While all aspects of open-field behaviour were impaired, the degree of impairment was directly related to the degree of motoric complexity. Deficits were also observed on non-visual sensorimotor coordination tasks and in olfactory discrimination. Histologically, neuron loss, gliosis, vacuolation and congophilic angiopathy were observed in several of the brain regions/fibre tracts believed to contribute to the control of some of the assessed behaviours. The aluminium treatment had very selective effects on both behaviour and brain histology, inducing several features observed in DAT. Behaviourally, the treatment induced impaired spatial reference memory; reduced ambulation; disturbed olfactory function and induced the premature development of the senile pattern of swimming. Histologically, significant neuron loss and gliosis were observed in the hippocampus, entorhinal cortex, amygdala, medial septum, pyriform and pr-frontal cortex. In addition, the brain distribution of congophilic angiopathy was significantly increased by the treatment. The lecithin treatment had effects on both non-cognitive and cognitive aspects of behaviour. The effects of aging on open-field ambulation and rearing were partially ameliorated by the treatment. A similar effect was observed for single-trial passive avoidance performance. Age-dependent improvements in acquisition/retention were observed in 17-23 month mice and Morris place task performance was improved in 11 and 17 month mice. Histologically, a partial sparing of neurons in the cerebellum, hippocampus, entorhinal cortex and subiculum was observed.

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Background Yellow filters are sometimes recommended to people with low vision. Our aim was investigate the effects of three commercial yellow filters on visual acuity and contrast sensitivity (with and without glare) and reading (without glare) under conditions of forward light scatter (FLS). Method Fifty-five healthy subjects were assessed with Corning Photochromic Filters (CPFs) 450, 511 and 527 and a filter producing FLS. The effects on log MAR visual acuity, Pelli–Robson contrast sensitivity with and without glare, and reading (measured with MNRead charts) without glare were determined. Results Statistically significant differences were found between the overall effect of glare and between CPFs for visual acuity and contrast sensitivity. A gradual decline in visual acuity, contrast sensitivity and reading with increasing CPF absorption was noted. Conclusion Effects of CPF450, 511, 527 on visual acuity, contrast sensitivity and reading under conditions of FLS were negative but not clinically significant.

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The pattern of senile plaques was investigated in various brain regions of six SDAT brains. In 91 pattern analyses, the regularly spaced clump was the most common pattern found in 64.8% of analyses. Clumping due to large aggregations of uncored plaques in sulci was also common. Regularly spaced clumps were equally common in the hippocampus and neocortex. The pattern of plaques varied in different tissue sections from the same brain region. Cored and uncored plaques presented a similar range of patterns but their pattern varied when they were both present in the same tissue section. Both clump diameter and the intensity of clumping were positively correlated with cored but unrelated to uncored plaque density. Plaques may develop in regular clumps on subcortical afferents and during development of the disease the clumps may spread laterally and ultimately coalesce.

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The present study explores strategies used to legitimize the transfer of organizational practices in a situation of institutional upheaval. We apply the logic of social action (Risse, 2000) to analyze the effectiveness of consequence-based action and communication-based action, in terms of higher coordination, lower conflict, and overall higher economic performance. Consequence-based legitimation is obtained by using a system of distributor incentives tied to performance of specific tasks, while communicative legitimation can be achieved by recommendations and warnings. Our setting is an export channel to European emerging economies. Our results indicate that in the absence of legitimacy, as manifested in discretionary legal enforcement, consequence-based legitimation is more effective than communicative legitimation in reducing conflict, increasing coordination, and ultimately in improving the performance of the export dyad. © 2014 Elsevier Inc.

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We examine the impact of the fiber type and dispersion management on the performance of a 16 × 40 Gb/s dense wavelength-division-multiplexing nonreturn-to-zero transmission system. The transmission line is composed of G.652 or G.655 fiber with periodic dispersion compensation and hybrid Raman erbium-doped fiber amplifier amplification.

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We examine impact of the fiber type and nonlinear management over the performance of a 16x40Gb/s DWDM NRZ transmission system. The line is constituted of 3x100km of G.652 or G.655 fiber with hybrid Raman-EDFA amplification.

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The effects of lipoic acid and dihydrolipoic acid were explored on total thiol maintenance in diabetic and non-diabetic human erythrocytes in vitro over 22 hr in a 37°C incubation system with no added glucose. Over 18-22.5 hr after treatment in both non-diabetic and diabetic cells, lipoic acid (1 mM) was associated with greater loss of cellular thiols than dihydrolipoic acid (1 mM), compared to respective control values. At 0.1 mM, in non-diabetic cells, although lipoic acid-treated cells' thiol levels were significantly lower than control, there was no significant difference between dihydrolipoic acid-treated cells and control cells regarding thiol levels. In addition, at 0.1 mM, dihydrolipoic acid-treated diabetic cells showed a reduction in thiol levels compared to control. At 0.01 mM, lipoic acid-treated cells had significantly lower measured thiol levels compared with diabetic cells exposed to dihydrolipoic acid, whereas in non-diabetic cells, dihydrolipoic acid-treated erythrocytic thiol levels were significantly greater than those treated with lipoic acid, although there were no other significant differences between the groups. At 22.5 hr, control values of methaemoglobin rose to 6.4 ± 1.1% in diabetic cells and 3.6 ± 2.1% in non-diabetic cells. Lipoic acid (1 mM) showed greater methaemoglobin formation in diabetic rather than non-diabetic cells (13.6 ± 1.5% versus 11.6 ± 1.5%), whereas dihydrolipoic acid-treated diabetic and non-diabetic cells were less potent in methaemoglobin generation (8.5 ± 2.4% and 8.4 ± 1.4%, respectively). These studies suggest that in certain circumstances such as hypoglycaemia, lipoic acid administration may actually be detrimental to cellular oxidant protection status. © 2006 The Authors.

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Portfolio analysis exists, perhaps, as long, as people think about acceptance of rational decisions connected with use of the limited resources. However the occurrence moment of portfolio analysis can be dated precisely enough is having connected it with a publication of pioneer work of Harry Markovittz (Markovitz H. Portfolio Selection) in 1952. The model offered in this work, simple enough in essence, has allowed catching the basic features of the financial market, from the point of view of the investor, and has supplied the last with the tool for development of rational investment decisions. The central problem in Markovitz theory is the portfolio choice that is a set of operations. Thus in estimation, both separate operations and their portfolios two major factors are considered: profitableness and risk of operations and their portfolios. The risk thus receives a quantitative estimation. The account of mutual correlation dependences between profitablenesses of operations appears the essential moment in the theory. This account allows making effective diversification of portfolio, leading to essential decrease in risk of a portfolio in comparison with risk of the operations included in it. At last, the quantitative characteristic of the basic investment characteristics allows defining and solving a problem of a choice of an optimum portfolio in the form of a problem of quadratic optimization.

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The aim of this paper is to study a generalized form of elliptic-type integrals which unify and extend various families of elliptic-type integrals studied recently by several authors. In a recent communication [1] we have obtained recurrence relations and asymptotic formula for this generalized elliptic-type integral. Here we shall obtain some more results which are single and multiple integral formulae, differentiation formula, fractional integral and approximations for this class of generalized elliptic-type integrals.