Claude Elwood Shannon e a symbolic analysis of relay and switching circuits: tornando o computador uma máquina semiótica.

O nome de Claude Elwood Shannon não é totalmente estranho aos pesquisadores de Comunicação Social. No entanto, parte de sua importância para a história da comunicação no século XX é pouco conhecida. Sua dissertação de mestrado e o artigo dela derivado (A Symbolic Analysis of Relay and Switching Circuits) foram essenciais para que o computador se tornasse uma máquina de comunicação e, conseqüentemente, penetrasse em nossa sociedade na forma como ocorre hoje. Este artigo revisa o primeiro grande trabalho de Shannon e explicita sua participação no contexto atual da comunicação.

Capital flows and monetary control under a domestic currency substitution regime: the recent Brazilian experience

The 90s have witnessed a resumption in capital flows to Latin America. due to the conjugation of low interest rates in the US and economic reforms in most LA countries. In Brazil. however. substantial capital flows have becn induced by the extremely high domestic interest rates practiced by the Central Bank as a measure of last reson given the absence of successful stabilization policies. These very high interest rates were needed to prevent capital flight in a context of a surprisingly stable inflation rate above 20% a month. and keep interest bearing govemment securities preferable to foreign assets as money substitutes. We carefully describe how this domestic currency substitution regime (interest bearing govemment securities are substituted for MIas cash holdings) requires the Central Bank to renounce aoy control over monerary aggregates. In this domestic currency substitution regime. hyperinflation is the most likely outcome of an isolated (i.e.. without fiscal adjusanents) attempt by the Brazilian Central Bank to control money.

Elasticity of substitution between capital and labor: a panel data approach

This paper estimates the elasticity of substitution of an aggregate production function. The estimating equation is derived from the steady state of a neoclassical growth model. The data comes from the PWT in which different countries face different relative prices of the investment good and exhibit different investment-output ratios. Then, using this variation we estimate the elasticity of substitution. The novelty of our approach is that we use dynamic panel data techniques, which allow us to distinguish between the short and the long run elasticity and handle a host of econometric and substantive issues. In particular we accommodate the possibility that different countries have different total factor productivities and other country specific effects and that such effects are correlated with the regressors. We also accommodate the possibility that the regressors are correlated with the error terms and that shocks to regressors are manifested in future periods. Taking all this into account our estimation resuIts suggest that the Iong run eIasticity of substitution is 0.7, which is Iower than the eIasticity that had been used in previous macro-deveIopment exercises. We show that this lower eIasticity reinforces the power of the neoclassical mo deI to expIain income differences across countries as coming from differential distortions.

Import substitution and economic growth

In spite of Latin America s dismal economic performance between the 1950s and 1980s, the region experienced strong capital deepening. Furthermore, pro- ductivity (measured as TFP) grew at low rates in comparison with the U.S. In this paper, we suggest that all these facts can be explained as a consequence of the restrictive trade regime adopted at that time. Our analytical framework is based on a dynamic Heckscher-Ohlin model, with scale economies in the capital- intensive sector. We assume an economy that is initially open and specialized in the production of labor-intensive goods. The trade regime is modeled as a move to a closed economy. The model produces results consistent with the Latin American experience. Speci cally, for a su¢ ciently small country, there will be no long-run growth in income per capita, but capital per capita will increase. As a result, measured TFP will fall.

Total gastrectomy with substitution of stomach by jejunal pouch with and without duodenal passage. Study in rats

A comparison was done between the F. Paulino jejunal pouch (FP) and a jejunal pouch (JP) as esophagusduodenum interpositional graft, for replacing the stomach after total gastrectomy. It was investigated the effect of the two procedures on esophagus histology, nutritional state and serum gastrin in rats. Methods: Male Wistar rats weighing 282±17g were randomly submitted to sham operation (S), FP and JP after total gastrectomy. After eight weeks the rats were killed with overdose of anesthetic and tissue was taken from the distal esophagus for histology. Serum levels of total proteins, albumin, iron, transferring, folate, cobalamine, calcium, as well as serum gastrin were determined. Survival was considered. Results: Fourty six rats were operated and thirty survived for eight weeks. Five (33.3%) died after FP and 11 (52.3%) after JP (p<0.05). Postoperative esophagitis occurred in 6 JP rats. At 8th week, no difference was observed on body weight when compared FP and JP rats (p>0.05). The JP rats had a significant decrease in serum albumin, glucose, transferrin, iron, folate and calcium, compared to sham (p<0.05). Serum gastrin, iron and calcium were significantly higher in JP rats than in FP rats (p<0.05). In FP rats, transferrin and cobalamine showed significant decrease comparing the preoperative with 8th week levels (p<0.05). Conclusion: F. Paulino pouch in rats had lower mortality than JP, and esophagitis was not detected in it. JP rats had serum gastrin, iron and calcium unaffected, possibly because of preservation of duodenal passage

Effects of strontium and calcium simultaneous substitution on electrical and structural properties of Pb1-x-y Ca (x) Sr (y) TiO3 thin films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Esophagectomy and substitution of the thoracic esophagus in dogs

OBJETIVO: Avaliar, em cadáveres de cães, uma técnica para remoção do esôfago torácico sem toracotomia e dois métodos de substituição do esôfago torácico. MÉTODOS: Foram utilizados 27 cadáveres de cães. Estes foram aleatoriamente divididos em três grupos de nove animais, em que se estudou: G1 - esofagectomia torácica total pelo método de invaginação retrógrada; G2 - esofagectomia torácica total com substituição esofágica pelo estômago inteiro; G3 - esofagectomia torácica total com substituição esofágica por um gastrotubo confeccionado de acordo com a técnica de Büchler de gastroplastia por rotação do fundo. Após a ressecção esofágica no grupo 1, a integridade da rota intratorácica foi avaliada por endoscopia e solução de azul de metileno a 1%. RESULTADOS: A ruptura da pleura visceral ocorreu em todos os animais, especialmente no terço caudal. Entretanto, a rota transtorácica mediastinal permitiu a elevação de ambos os substitutos esofágicos (G2 e G3) para a realização da anastomose com a extremidade caudal do esôfago cervical. CONCLUSÕES: A substituição por estômago inteiro apresentou menor tensão na anastomose, maior facilidade e rapidez comparada à técnica de gastroplastia por rotação do fundo. Os resultados em cadáveres suportam a realização de estudos clínicos para validação da técnica.

Comparative Study Between Porcine Small Intestinal Submucosa and Buccal Mucosa in a Partial Urethra Substitution in Rabbits

Purpose: Several urethral conditions may require tissue substitution. One collagen-base biomaterial that recently emerged as an option is small intestinal submucosa (SIS). The aim of this study was to compare the results of SIS and buccal mucosa for urethral substitution in rabbits.Materials and Methods: Thirty-six North Folk male rabbits were randomized into three groups. In all animals, a 10 x 5 mm urethral segment was excised, and the urethral defect was repaired using a one-layer SIS patch (group I [GI]); four-layer SIS (group II [GII]); or buccal mucosa (group III [GIII]). Urethrography was performed preoperatively and after 12 weeks. After sacrifice, graft retraction was objectively measured using Scion Image (R) computer analysis and by calculation of ellipse area. The grade of fibrosis, inflammatory reaction, vascular/epithelial regeneration, and collagen III/I ratio were analyzed by hematoxylin/eosin and Picrosirius red staining.Results: Urethrography confirmed a wide urethral caliber without any signs of strictures after surgery. Urethral fistulae was diagnosed in 8.3% of cases (1 animal each group). Average graft shrinkage was 55.2% in GI; 44.2% in GII; and 57.2% in GIII (p < 0.05). The intensity of chronic inflammation, fibrosis, epithelium regeneration, and neovascularization was similar in all groups (p > 0.05). Collagen III/I ratio was higher in GII (GI: 119.6; GII: 257.2 and GIII: 115.0); p < 0.01.Conclusions: The four-layer SIS is more advantageous than the one-layer SIS and buccal mucosa for urethral substitution in rabbits.

Influence of the substitution of Y2O3 for CeO2 on the mechanical and microstructural properties of silicon nitride

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

NATURAL PRODUCT SUBSTITUTION PATTERN AND SKELETAL RECOGNITION METHOD

This work describes a methodology for identification of skeletal types of diterpenes based on data base with 1500 compounds isolated from Asteraceae. One program named BOTOCSYS was built with the codification of the compounds and their botanical sources. An example of identification of a new substance is given.

The change in magnetic properties of Fe3Al compound due to substitution of Fe by Co

The magnetic moment using self-consistent spin-polarized energy band calculations of Fe3Al and Fe2CoAl Heusler phases are presented. These results are compared with the experimental values obtained from the magnetization curves of these materials. (C) 2004 Elsevier B.V. All rights reserved.

Effect of substitution of [Pd(PPh3)(4)] by related compounds as catalysts in reactions of organic syntheses

The effect of substitution of [Pd(PPh3)(4)], which is unstable in air, by complexes of the type [MCl2L2] (M = Pd, Pt; L = AsPh3, SbPh3), [PdL4](L = PPh3, AsPh3, SbPh3) and [NiX2(PPh3)(2)] on the syntheses of thioethers, acetylenes and ketones is described.

Dietary macronutrients and performance and plasma hormone and metabolite levels of broiler chickens fat by carbohydrate substitution

The present experiment was aimed to study the effects of an isocaloric substitution of fat by carbohydrate calories while maintaining the same CP content - on some endocrine parameters and key metabolites of the lipid (L), protein (CP) and carbohydrate (CHO) metabolism and muscle cell membrane integrity of broiler chickens. Ninety male broiler chicks (Cobb) were obtained at 1-day old and raised in an environmentally controlled room. Food and water was provided ad libitum. At day 7, the chicks were provided with the experimental diets: Control diet (CON: 20% CP; 9.1% L; 39.6% CHO), Low lipid diet (LowL: 22% CP; 3.36% L; 59.7% CHO), and low carbohydrate diet (LowCHO: 22% CP; 8.09% L; 46.7% CHO). T e chickens fed the CON manifested the best growth rate feed conversion compared to both other groups. The CO chickens showed the highest plasma T-3 Concentrations at 14 days of age as compared to both LowL and LowCHO chickens. At 35 days of age however, LowL chickens were characterized by the highest plasma T-3 levels. Overall, CON birds had the highest plasma T-4 levels (P < 0.0001) compared to LowL and LowCHO chickens. Plasma corticosterone levels were not affected by diet composition. Glucose levels increased towards the end of the experimental period, but there was no overall effect of diet composition on plasma glucose levels. Chickens fed the CON diet were consistently characterized by the highest plasma uric acid levels compared to LowL and LowCHO chickens. Irrespectively of diet, plasma triglyceride levels were high at 14 days of age, then decreased and finally increased again during the last week. This latter increase was most pronounced for the CON chickens and is congruous with their high fat deposition. At 28 days of age, a significant effect of diet was observed, as CON birds had lower plasma free fatty acid (FFA) levels compared to LowL but not to LowCHO chickens. However there was no overall effect of diet composition on plasma FFA levels. Creatine kinase (CK) activities increased significantly with age and were consistently higher in CON chickens. In conclusion, fast growth in broiler chickens is positively correlated with catabolism of protein from dietary or endogenous origin and (muscle) cell membrane disruption as reflected in high plasma uric acid levels and CK activity, respectively. The currently investigated substitution of fat by CHO had no marked effects on endocrine functioning and intermediary metabolism, but this does not exclude that larger substitutions between both nutrients can have an effect.