Análise estatística e optimização de perfis de redução termoprogramada (TPR)

The effect of operational variables and their interaction in TPR profiles was studied using a fractional factorial experimental design. The heating rate and the reducing agent concentration were found to be the most important variables determining the resolution and sensitivity of the technique. They showed opposite effects. Therefore, they should be manipulated preferentially in order to obtain optimized TPR profiles. The effect of sample particle size was also investigated. The tests were carried out within a Cu/Zn/Al2O3 catalyst used for the water-gas shift reaction that presented two distinct species of Cu2+ in TPR profiles.

Internal ambience of bee colonies submitted to strengthening management by adding broods

This study aimed to investigate the ideal brood area to be introduced for strengthening Apis mellifera colonies, considering variations in the hive's internal ambience. Therefore, eight colonies were equipped with data loggers for recording variations in temperature and humidity inside the hives. Then, these colonies were split in four treatments involving the swapping of four, three, two and one brood comb between strong and weak colonies. Growth in the amount of brood and food stores to the four colony strengthening treatments was assessed counting the comb cells to record changes in the brood and food area. The colonies tended to restore their normal thermoregulation within four hours after they had been manipulated and the hive cover had been closed, which quickly increased brood area in the receiving colonies. Results showed that adding up to three brood combs constitute an important alternative for strengthening Apis mellifera colonies because it did not interfere with nest thermoregulation, speeded up population growth in weak colonies and did not affect the development of strong colonies.

Gastroduodenal resistance and neural mechanisms involved in saline flow decrease elicited by acute blood volume expansion in anesthetized rats

We have previously demonstrated that blood volume (BV) expansion decreases saline flow through the gastroduodenal (GD) segment in anesthetized rats (Xavier-Neto J, dos Santos AA & Rola FH (1990) Gut, 31: 1006-1010). The present study attempts to identify the site(s) of resistance and neural mechanisms involved in this phenomenon. Male Wistar rats (N = 97, 200-300 g) were surgically manipulated to create four gut circuits: GD, gastric, pyloric and duodenal. These circuits were perfused under barostatically controlled pressure (4 cmH2O). Steady-state changes in flow were taken to reflect modifications in circuit resistances during three periods of time: normovolemic control (20 min), expansion (10-15 min), and expanded (30 min). Perfusion flow rates did not change in normovolemic control animals over a period of 60 min. BV expansion (Ringer bicarbonate, 1 ml/min up to 5% body weight) significantly (P<0.05) reduced perfusion flow in the GD (10.3 ± 0.5 to 7.6 ± 0.6 ml/min), pyloric (9.0 ± 0.6 to 5.6 ± 1.2 ml/min) and duodenal (10.8 ± 0.4 to 9.0 ± 0.6 ml/min) circuits, but not in the gastric circuit (11.9 ± 0.4 to 10.4 ± 0.6 ml/min). Prazosin (1 mg/kg) and yohimbine (3 mg/kg) prevented the expansion effect on the duodenal but not on the pyloric circuit. Bilateral cervical vagotomy prevented the expansion effect on the pylorus during the expansion but not during the expanded period and had no effect on the duodenum. Atropine (0.5 mg/kg), hexamethonium (10 mg/kg) and propranolol (2 mg/kg) were ineffective on both circuits. These results indicate that 1) BV expansion increases the GD resistance to liquid flow, 2) pylorus and duodenum are important sites of resistance, and 3) yohimbine and prazosin prevented the increase in duodenal resistance and vagotomy prevented it partially in the pylorus

Modulation of the perception of temporal order by attentional and pre-attentional factors

When two stimuli are presented simultaneously to an observer, the perceived temporal order does not always correspond to the actual one. In three experiments we examined how the location and spatial predictability of visual stimuli modulate the perception of temporal order. Thirty-two participants had to report the temporal order of appearance of two visual stimuli. In Experiment 1, both stimuli were presented at the same eccentricity and no perceptual asynchrony between them was found. In Experiment 2, one stimulus was presented close to the fixation point and the other, peripheral, stimulus was presented in separate blocks in two eccentricities (4.8º and 9.6º). We found that the peripheral stimulus was perceived to be delayed in relation to the central one, with no significant difference between the delays obtained in the two eccentricities. In Experiment 3, using three eccentricities (2.5º, 7.3º and 12.1º) for the presentation of the peripheral stimulus, we compared a condition in which its location was highly predictable with two other conditions in which its location was progressively less predictable. Here, the perception of the peripheral stimulus was also delayed in relation to the central one, with this delay depending on both the eccentricity and predictability of the stimulus. We argue that attentional deployment, manipulated by the spatial predictability of the stimulus, seems to play an important role in the temporal order perception of visual stimuli. Yet, under whichever condition of spatial predictability, basic sensory and attentional processes are unavoidably entangled and both factors must concur to the perception of temporal order.

A detailed description of an economical setup for electroporation of chick embryos in ovo

One of the challenges of the postgenomic era is characterizing the function and regulation of specific genes. For various reasons, the early chick embryo can easily be adopted as an in vivo assay of gene function and regulation. The embryos are robust, accessible, easily manipulated, and maintained in the laboratory. Genomic resources centered on vertebrate organisms increase daily. As a consequence of optimization of gene transfer protocols by electroporation, the chick embryo will probably become increasingly popular for reverse genetic analysis. The challenge of establishing chick embryonic electroporation might seem insurmountable to those who are unfamiliar with experimental embryological methods. To minimize the cost, time, and effort required to establish a chick electroporation assay method, we describe and illustrate in great detail the procedures involved in building a low-cost electroporation setup and the basic steps of electroporation.

Design of automatic control system for the precipitation of bromelain from the extract of pineapple wastes

In this work, bromelain was recovered from ground pineapple stem and rind by means of precipitation with alcohol at low temperature. Bromelain is the name of a group of powerful protein-digesting, or proteolytic, enzymes that are particularly useful for reducing muscle and tissue inflammation and as a digestive aid. Temperature control is crucial to avoid irreversible protein denaturation and consequently to improve the quality of the enzyme recovered. The process was carried out alternatively in two fed-batch pilot tanks: a glass tank and a stainless steel tank. Aliquots containing 100 mL of pineapple aqueous extract were fed into the tank. Inside the jacketed tank, the protein was exposed to unsteady operating conditions during the addition of the precipitating agent (ethanol 99.5%) because the dilution ratio "aqueous extract to ethanol" and heat transfer area changed. The coolant flow rate was manipulated through a variable speed pump. Fine tuned conventional and adaptive PID controllers were on-line implemented using a fieldbus digital control system. The processing performance efficiency was enhanced and so was the quality (enzyme activity) of the product.

O dólar e os desequilíbrios globais

The global expansion of capitalism under American hegemony in the second half of the 20th century has changed the international division of labor and center-periphery scheme proposed under British hegemony. Under the new international division of labor, the United States is forced to generate an ever growing deficit in their trade account in order to accommodate the "mercantilist' expansion of Asian countries, produced by the trans-nationalization of big capital, under American aegis. This form of global economic articulation is at the root of the rupture of the Bretton Woods system and the growing financial liberalization imposed by the hegemonic power over other countries since the 80s.

Mudança em tempos de globalização: o capitalismo não é mais progressista?

Technical progress and economic development are promotions of capitalism, says a well known idea hereby contradicted. Recent changes under neoliberalism show that the more freedom of move to capital the less development of productive forces. There was no synchronicity and coherence fostering economic growth between changes at the micro level of techno-productive and managerial innovations and the ones at the macro level of institutional structures and economic policy. Empowerment of finance capital and monopolies got them opportunity to control the state and set its economic policy to support fictitious capital accumulation and to rule restructuring of corporate management. Surplus redistribution favoring finance capital is a burden to be carried on the back of society's productive structures, lowering investment, employment and growth. Focusing Latin America and Brazil, the same picture is seen, worsened by external fragility that deepens historical dependency.

Economia e retórica: o capítulo brasileiro

Considering the rise of the discussion about the rhetoric of economics at the beginning of the 1980's, the paper aims to show: 1) the relation between the origin of this issue in the academic field and the ascension of the so labeled "neoliberalism" as a doctrine and a collection of capitalist practices perceived at the same time; and 2) the consequences produced by this idea, overseas born, when it meets a peripherical reality like the Brazilian one. In the first case, we are going to show the importance of Hayek's reflections about the inadequateness of neoclassical discourse to the aim of ideologically legitimate the market society. In the second we are going to point out that, taking the consequences of the rhetoric project in Brazil, it can be seeing as an additional chapter of "the ideas out of its place" that comes marking the Brazilian history of the ideas.

Um modelo macrodinâmico pós-keynesiano de simulação

A post-keynesian macro-dynamic model of simulation. The objective of this article is to present the structure and the simulation results of a one-sector macro-dynamic model that embeds some elements of the post-keynesian theory. The computational simulation of the model replicates some important features of capitalist dynamics as the phenomenon of cyclical growth, the long-run stability of the profit rate and functional distribution of income, the maintenance of idle-capacity in the long-run and the occurrence of a single episode of deep fall in real economic activity, which is in accordance with the rarity character of great crashes in the history of capitalism. Moreover, the simulation results show that a great reduction in inflation rate will be followed by an increase of financial fragility, increasing the like-hood of a great depression. As a policy advice derived from the simulation results, we can state that the Central Bank should never promote big reductions in inflation rate.

'TINA', Aids, and the underdevelopment problem in Africa

The assumption that 'There Is No Alternative' (TINA) to capitalism as practiced in the United States of America and Western Europe has been the bane of aids effectiveness in assisting to solve the underdevelopment problem in Africa. This paper attempts to show that except there is a fundamental reorientation in the conceptualization of capitalism-free market and democracy-the underdevelopment problem would only be further complicated with aids.

Globalization, nation-state and catching up

Globalization and nation-states are not in contradiction, since globalization is the present stage of capitalist development, and the nation-state is the territorial political unit that organizes the space and population in the capitalist system. Since the 1980s, Global Capitalism constitutes the economic system characterized by the opening of all national markets and a fierce competition between nation-states. Developing countries tend to catch up, while rich countries try to neutralize such competitive effort, using globalism as an ideology, and conventional orthodoxy as a strategy. Middle-income countries that are catching up in the realm of globalization are the ones that count with a national development strategy. This is broadly the case of the dynamic Asian countries. In contrast, Latin American countries have no longer their own strategy, and grow less. To add data to the argument, the author conducts an econometric test comparing these two groups of countries, and three variables: the rate of investment, the current account deficit or surplus that would indicate or not a competitive exchange rate, and public deficit.

Michal Kalecki, um pioneiro da teoria econômica do desenvolvimento

Kalecki made important contributions to development economics, which rank him among the founding fathers of this area of our discipline. The objective of this paper is to give an account of his contributions, and in particular of his conception of the peculiarities and the way of functioning of the underdeveloped economies, and of the barriers that limits their capacity for high and sustained long run growth. As most socialist economists of his time, he was skeptic about the possibilities of overcoming underdevelopment under capitalism. However, in contradistinction to other pioneers of development economics, Kalecki did not stress the international forces that hamper development, but put the accent rather in the internal institutions and social and political determinants. In particular, the feudal and semi-feudal conditions in agriculture, the reduced market ensuing from income concentration and widespread monopolization of the economy, and the lack of willingness of entrepreneurs to carry out the necessary investments. Accordingly, his economic policy recommendations emphasized also the domestic aspects involved.

The 2008 financial crisis and neoclassical economics

The 2008 global financial crisis was the consequence of the process of financialization, or the creation of massive fictitious financial wealth, that began in the 1980s, and of the hegemony of a reactionary ideology, namely, neoliberalism, based on self-regulated and efficient markets. Although capitalism is intrinsically unstable, the lessons from the stock-market crash of 1929 and the Great Depression of the 1930s were transformed into theories and institutions or regulations that led to the "30 glorious years of capitalism" (1948-1977) and that could have avoided a financial crisis as profound as the present one. It did not because a coalition of rentiers and "financists" achieved hegemony and, while deregulating the existing financial operations, refused to regulate the financial innovations that made these markets even more risky. Neoclassical economics played the role of a meta-ideology as it legitimized, mathematically and "scientifically", neoliberal ideology and deregulation. From this crisis a new capitalism will emerge, though its character is difficult to predict. It will not be financialized but the tendencies present in the 30 glorious years toward global and knowledge-based capitalism, where professionals will have more say than rentier capitalists, as well as the tendency to improve democracy by making it more social and participative, will b e resumed.

Estado e economia na Coreia do Sul - do Estado desenvolvimentista à crise asiática e à recuperação posterior

The State and the economy in South Korea: from the developmentist state to the Asian crisis and later recovery. The article focuses on the institutions of South Korean capitalism and on the interactions between the state and the economy. The economic model in South Korea was characterized by a very interventionist state, which played a very active role in the process of industrialization. However, South Korea suffered a severe crisis in 1997, attributed by many authors to the distortions inherent to strong state intervention. The article shows that the crisis was a result of the combination between internal economic fragilities and a rapid process of financial deregulation, which undermined the state's capacity of control. The crisis, nevertheless, does not disqualify the role of the national institutions in the very successful process of industrialization. Despite the reforms, the Korean capitalism conserves much of the previous model of business organization and industrial relations. The state continues strong and played active role in the process of economic reforms. There are, nevertheless, doubts about the impacts of the reforms and the new configuration of Korean capitalism. They will depend on the current transformations in world economy and in the East Asian countries.