Increase in ghrelin levels after weight loss in obese Zucker rats is prevented by gastric banding.

Obes Surg. 2007 Dec;17(12):1599-607. Epub 2007 Nov 30. Increase in ghrelin levels after weight loss in obese Zucker rats is prevented by gastric banding. Monteiro MP, Ribeiro AH, Nunes AF, Sousa MM, Monteiro JD, Aguas AP, Cardoso MH. Department of Anatomy and UMIB (Unit for Multidisciplinary Biomedical Research) of ICBAS (Abel Salazar Institute for the Biomedical Sciences), University of Porto, 4099-003 Porto, Portugal. [email protected] Abstract BACKGROUND: Gastric banding is thought to decrease appetite in addition to the mechanical effects of food restriction, although this has been difficult to demonstrate in human studies. Our aim was to investigate the changes in orexigenic signals in the obese Zucker rat after gastric banding. METHODS: Obese Zucker rats (fa/fa) were submitted to gastric banding (GBP), sham gastric banding fed ad libitum (sham), or sham operation with food restriction, pair-fed to the gastric banding group (sham-PF). Lean Zucker rats (fa/+) were used as additional controls. Body weight and food intake were daily recorded for 21 days after surgery when epididymal fat was weighed and fasting ghrelin and hypothalamic NPY mRNA expression were measured. RESULTS: Gastric banding in obese Zucker rats resulted in a significant decrease of cumulative body weight gain and food intake. Furthermore, gastric banded rats were leaner than Sham-PF, as expressed by a significantly lower epididymal fat weight. Ghrelin levels of gastric banded rats were not increased when compared to sham-operated animals fed ad libitum and were significantly lower than the levels of weight matched sham-PF rats (1116.9 +/- 103.3 g GBP vs 963.2 +/- 54.3 g sham, 3,079.5 +/- 221.6 sham-PF and 2,969.9 +/- 150.9 g lean rats, p < 0.001); hypothalamic NPY mRNA expression was not increased in GBP when compared to sham-operated rats. CONCLUSION: In obese Zucker rats, GBP prevents the increase in orexigenic signals that occur during caloric deprivation. Our data support the hypothesis that sustained weight loss observed after gastric banding does not depend solely on food restriction

Forests as promoters of water ecosystem services: insights from Portugal

Forests provide multiple ecosystem services, with relevance for the ones related to water. It is widely accepted that forests greatly influence the water cycle, promoting evapotranspiration, improving infiltration, reducing surface runoff and consequently soil erosion, although sometimes at expenses of a reduction in total water yield. In fact, forests are targeted for several measures to restore freshwater and land ecosystems, conserving biodiversity and at the same time improving the revenues of landowners, especially if Payments for Ecosystem Services (PES) are in place. However, the environmental effectiveness of these measures is not always acknowledged, especially due to the lack of local studies. Therefore, the objective of this presentation is to gather information based on modelling exercises applied to case-studies in Portugal, in which forests influence the provision of ecosystem services related to water in terms of quantity and quality. First, the results from an econometric model based on spatial variables applied to continental Portugal will be presented. Results suggested the existence of a positive and significant effect of local forest cover on water treatment cost savings of 0.056%. Secondly, scenarios of afforestation were simulated in SWAT (Soil and Water Assessment Tool) for two watersheds of northern Portugal. Results revealed that forests have a positive role on the regulation of water, in particular for the scenario of native deciduous type of trees, such as oak. Moreover, forests influence water quality, in terms of less nitrates in the river, and less soil erosion, when compared to a scenario of agricultural expansion. Lastly, a SWAT application in a small watershed in Central Portugal with scenarios of afforestation vs. fires, showed that soil erosion protection and water quality regulation provided by forests might be negatively affected by fire occurrence. Overall, further work should be done to consider fire risk over PES schemes applied to the Mediterranean forest.info:eu-repo/semantics/publishedVersio

Avaliação do acervo de normas sobre construção no Brasil

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Vibrational properties of amorphous silicon from tight-binding O(N) calculation

We present an O(N) algorithm to study the vibrational properties of amorphous silicon within the framework of tight-binding approach. The dynamical matrix elements have been evaluated numerically in the harmonic approximation exploiting the short-range nature of the density matrix to calculate the vibrational density of states which is then compared with the same obtained from a standard O($N^4$) algorithm. For the purpose of illustration, an 1000-atom model is studied to calculate the localization properties of the vibrational eigenstates using the participation numbers calculation.Comment: 5 pages including 5 ps figures; added a figure and a few references; accepted in Phys. Rev.

Comportamento de cultivares de mandioca com diferentes características foliares submetidas a diversas densidades de plantio

A field study was conducted at the east coast of the State of Ceará, Brazil, from march 1978 to august 1979, which included two growing seasons. The objective was to study the behavior of two cassava cultivars (Manihot esculenta Crantz), Do Céu and Saracura with broad and narrow lobed leaves, respectively, grown under varying population densities. The pattern of the plant dry matter accumulation and distribution was also studied. The Leaf Area index (IAN showed maximum values in the 4th and 15th months after planting, corresponding to the rainy seasons of 1978 and 1979. Cultivar Saracura showed higher IAF in all population densities, with the highest differences taking placa during the two rainy seasons. The IAF followed closely the amount of rainfall in the experimental area. Cultivar 'Saracura' had considerably smaller leaves than cultivar 'Do Céu'. Both cultivar showed larger leaves in the first growing season. Cultivar 'Saracura' slightly outyielded 'Do Céu' in total biomass. A greater proportion of the dry matter was diverted into the root tubers of 'Saracura' than in 'Do Céu'. As a consequence 'Saracura' had higher harvest index during alt stages of growth. For both cultivars the harvest index was highest in the 7th month after planting. The best performance of cultivar 'Saracura' does not seem to be related to its narrow leaf lobes but to the ability of this cultivar to rapidly produce a high IAF associated to the capacity to divert large proportion of dry matter to the root tubers. For both cultivars it was observed that a reduction in the proportion of dry matter diverted to the roots with the increase in plant population.Foi instalado, no município de Pacajus, litoral leste do Estado do Ceará, no período de março de 1978 a agosto de 1979, um ensaio de campo, com o objetivo de estudar o comportamento de duas cultivares de mandioca (Manihot esculenta Crantz), Saracura e Do Céu, constituídas de folhas com lóbulos estreitos e largos, respectivamente, em diferentes densidades populacionais. O estudo foi realizado durante os dois ciclos de crescimento da cultura e procurou identificar igualmente o efeito da deficiência hídrica causada à planta durante o período de estiagem entre os dois ciclos de crescimento. Foi estudado também o modelo de acumulação e distribuição de matéria seca pela planta. O índice de área foliar (IAF) das cultivares apresentou valores máximos aos quatro e quinze meses após o plantio, correspondentes aos períodos de chuva de 1978 e 1979. A cultivar Saracura apresentou maior IAF nas diversas populações estudadas ao longo dos dois ciclos de crescimento, com diferenças máximas registradas nos dois períodos de chuva. O IAF da cultura acompanhou aproximadamente a curva de precipitação pluviométrica. A cultivar Saracura apresentou área foliar unitária menor que a Do Céu. Ambas as cultivares apresentaram folhas maiores no primeiro ciclo de crescimento. A cultivar Saracura foi um pouco superior à Do Céu com relação à produção de biomassa e apresentou maior produção de raízes frescas e maior índice de colheita (IC). Ambas as cultivares apresentaram valores máximos de IC e teor de amido aos sete meses de plantio. O melhor desempenho da cultivar Saracura não parece estar associado à forma da folha em si, mas à grande capacidade dessa cultivar em formar rapidamente um elevado IAF e translocar grande proporção de matéria seca produzida para as raízes. Constatou-se uma tendência generalizada de redução de matéria seca das raízes com o aumento da população de plantio nas duas cultivares