Marcos Roberto Silva

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A heuristic based on genetic algorithms is proposed to the problem of configuring hub-and-spoke networks for trucking companies that operate less-than-truckload (LTL) services in Brazil. The problem consists of determining the number of consolidation terminals (also known as hubs), their locations and the assignment of the spokes to the hubs, aiming to(More)
Thyrotoxicosis might alter the hypothalamic-pituitary-adrenal (HPA) axis. We evaluated the effects of ghrelin and GHRP-6 on the HPA axis in 20 hyperthyroid patients and in 9 controls. Mean basal cortisol (μg/dl) and ACTH (pg/ml) levels were higher in hyperthyroidism (cortisol: 10.7 ± 0.7; ACTH: 21.5 ± 2.9) compared to controls (cortisol: 8.1 ± 0.7; ACTH:(More)
In thyrotoxicosis GH response to several stimuli is impaired, but there is no data on ghrelin-induced GH release in these patients. Ghrelin is a potent GH secretagogue and it also increases glucose levels in men. The aim of this study was to evaluate the effects of ghrelin (1 μg/kg), GHRP-6 (1 μg/kg) and GHRH (100 μg), i.v., on GH levels in 10 hyperthyroid(More)
A stability indicating reversed-phase liquid chromatography method is developed and validated for the determination of norfloxacin in a new formulation of extended-release tablets. The LC method is carried out on a Luna C(18) column (150 x 4.6 mm) maintained at 40 degrees C. The mobile phase is composed of phosphate buffer (0.04 M, pH 3.0)-acetonitrile(More)
GH responses to ghrelin, GHRP-6, and GHRH in Cushing's disease (CD) are markedly blunted. There is no data about the effect of reduction of cortisol levels with steroidogenesis inhibitors, like ketoconazole, on GH secretion in CD. ACTH levels during ketoconazole treatment are controversial. The aims of this study were to compare the GH response to ghrelin,(More)
Shirai, Y. & Ohkubo, T. (1954a). J. Biochem., Tokyo, 41, 337. Shirai, Y. & Ohkubo, T. (1954b). J. Biochem., Tokyo, 41, 341. Storey, I. D. E. (1950). Biochem. J. 47, 212. Storey, I. D. E. & Dutton, G. J. (1955). Biochem. J. 59,279. Storey, I. D. E. & Dutton, G. J. (1956). Proc. 3rd Int. Congr. Biochem., Brussel8, 1955, p. 162. Strominger, J. L., Kalckar, H.(More)
This paper describes a tabu search (TS) heuristic for the uncapacitated single allocation p -hub maximal covering problem. The objective is to determine the best location for p hubs and the assignment of each of the spokes to a single hub such that the total demand between pairs of nodes within a given coverage distance is maximized. We consider all nodes(More)