Respiratory chemoreceptor function in vertebrates - Comparative and evolutionary aspects

The sensing of blood gas tensions and/or pH is an evolutionarily conserved, homeostatic mechanism, observable in almost all species studied from invertebrates to man. In vertebrates, a shift from the peripheral O2-oriented sensing in fish, to the central CO2/pH sensing in most tetrapods reflects the specific behavioral requirements of these two groups whereby, in teleost fish, a highly O2-oriented control of breathing matches the ever-changing and low oxygen levels in water, whilst the transition to air-breathing increased the importance of acid-base regulation and O2-related drive, although retained, became relatively less important. The South American lungfish and tetrapods are probably sister groups, a conclusion backed up by many similar features of respiratory control. For example, the relative roles of peripheral and central chemoreceptors are present both in the lungfish and in land vertebrates. In both groups, the central CO2/pH receptors dominate the ventilatory response to hypercarbia (60-80), while the peripheral CO2/pH receptors account for 20-30. Some basic components of respiratory control have changed little during evolution. This review presents studies that reflect the current trends in the field of chemoreceptor function, and several laboratories are involved. An exhaustive review on the previous literature, however, is beyond the intended scope of the article. Rather, we present examples of current trends in respiratory function in vertebrates, ranging from fish to humans, and focus on both O2 sensing and CO2 sensing. As well, we consider the impact of chronic levels of hypoxia - a physiological condition in fish and in land vertebrates resident at high elevations or suffering from one of the many cardiorespiratory disease states that predispose an animal to impaired ventilation or cardiac output. This provides a basis for a comparative physiology that is informative about the evolution of respiratory functions in vertebrates and about human disease. Currently, most detail is known for mammals, for which molecular biology and respiratory physiology have combined in the discovery of the mechanisms underlying the responses of respiratory chemoreceptors. Our review includes new data on nonmammalian vertebrates, which stresses that some chemoreceptor sites are of ancient origin.

Blade design and forming for fans using finite elements

The necessity of adapting the standardized fan models to conditions of higher temperature has emerged due to the growth of concerning referring to the consequences of the gas expelling after the Mont Blanc tunnel accident in Italy and France, where even though, with 100 fans in operation, 41 people died. However, since then, the defied solutions have pointed to aerodynamic disadvantages or have seemed nonappropriate in these conditions. The objective of this work is to present an alternative to the market standard fans considering a new technology in constructing blades. This new technology introduces the use of the stainless steel AISI 409 due to its good adaptation to temperatures higher than 400��C, particularly exposed to temperatures of gas exhaust from tunnels in fire situation. Furthermore, it presents a very good resistance to corrosion and posterior welding and pressing, due to its alloyed elements. The innovation is centered in the process of a deep drawing of metallic shells and posterior welding, in order to keep the ideal aerodynamic superficies for the fan ideal performance. On the other hand, the finite element method, through the elasto-plastic software COSMOS permitted the verification of the thickness and structural stability of the blade in relation to the aerodynamic efforts established in the project. In addition, it is not advisable the fabrication of blades with variable localized thickness not even, non-uniform ones, due to the verified concentration of tensions and the difficulties observed in the forming. In this way, this study recommends the construction of blades with uniform variations of thickness. �� 2007 Springer.

Influence of grinding on the roundness, residual stresses and microstructure of VC131 steel analysed by varying the type of cutting fluid

This paper by R. E. Catai, E. C. Bianchi, P. R de ��guia and M. C. Alves reports on the results of an analysis made of roundness errors, residual stresses, and SEM micrographs of VC131 steel. The analysis involved workpieces ground with two types of cutting fluid: synthetic cutting fluid and emulsive oil. In this study, the cutting parameters were kept constant while the type of cutting fluid was varied. The amount of cutting fluid injected in the process was also varied, aiming to identify the ideal amount required to obtain good results without causing structural damage to the workpiece. The SEM analyses of roundness errors and residual stresses revealed that, of the two cutting fluids, emulsive oil provided better tensions due to its greater lubricating power.

Efeito de m��todos de determina����o de par��metros para o controle da irriga����o na efic��ncia do uso da ��gua do feijoeiro, sob tr��s diferentes l��minas de ��gua no solo

The objective of this research was to study three methods of parameter determination for irrigation control under different tensions in common bean (Phaseolus vulgaris L.). The treatments were a combination of three methods of parameter determination for irrigation control (tensiometer, water retention curve, USWB Class A pan) with three soil water tensions (1:-30 kPa; 2:-60, kPa both for the whole plant cycle; 3:-60 kPa for the vegetative phase and -30 kPa for the reproductive phase). The experimental design was randomized blocks, factorial 32 with three replicates. Although no significant effect on water use efficiency was found, a tendency for increasing water use efficiency in treatments with tensions of -60 kPa at the vegetative phase and -30 kPa at the reproductive phase was observed in all methods of parameter determination for irrigation control. Water was saved as less irrigation was applied during the vegetative phase and more irrigation at the reproductive phase. No precipitation was observed from June to September 1995, leading to a high yield and therefore to a higher water use efficiency.

Propriedades tensiom��tricas comparadas entre fragmentos do centro tend��neo do diafragma, peric��rdio fibroso e perit��nio parietal de bovinos n��o conservados e conservados em glicerina

The behaviour of the non conserved and 98% glycerin conserved specimens for periods of 30, 60 and 90 days of bovine diaphragma's tendinous center, fibrous pericardium and parietal peritoneum submitted to mechanical tests of traction, was observed in ten bovines between 30 months and 36 months of age, crossbreeds, males and females, collecting fragments of these aforesaid membranes in each animal. The diaphragma's tendinous center and parietal peritoneum did not suffered significant modification (p>0.05) in the values of tension when compared to the resistance tests of traction of non conserved and 98% glycerin conserved membranes. However, all the evaluated tissues showed significant increase (p��0.05) of the elongation values when conserved in 98% glycerin for until 90 days. It was also observed that fibrous pericardium is the one which supports greaters tensions. So, it to was concluded, that glycerin is efficient to the conservation of biological membranes besides modifying its mechanical properties.

Mondialisation et d��veloppement: un regard de l'Am��rique Latine et des Cara��bes

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On the consistency conditions to braneworlds in scalar-tensor gravity for arbitrary dimensions

We derive an one-parameter family of consistency conditions to braneworlds in the Brans-Dicke gravity. The General Relativity case is recovered by taking a correct limit of the Brans-Dicke parameter. We show that it is possible to build a multiple AdS brane scenario in a six-dimensional bulk only if the brane tensions are negative. Besides, in the five-dimensional case, it is showed that no fine tuning is necessary between the bulk cosmological constant and the brane tensions, in contrast to the Randall-Sundrum model. Copyright �� owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial- ShareAlike Licence.

Globalization and development

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Utiliza����o do brinquedo terap��utico na assist��ncia �� crian��a hospitalizada

This is an exploratory and descriptive study that was jointly carried out by Nursing Care and Occupational Therapy as part of a Research Project that intended to prepare children for elective surgery at the University of S��o Paulo's Hospital de Reabilita����o de Anomalias Craniofaciais. Objective: using toys as a therapeutic resource for relieving the child's real and unconscious tensions concerning hospitalization for surgical treatment at the HRAC - USP. Method: 44 children participated in the study. An observation form was used to collect data and it was applied at two separate times: the first time was the day before the surgery was to take place and the second on the day of the surgery just before the event. Twenty one variables were elaborated by the researchers to categorize behaviors regarding hospitalization. The resources used were: storytelling, dramatization and demonstration of nursing interventions with puppets dressed in surgical garb (gloves, surgical gown, mask and cap) with medical equipment commonly used in hospital. Results: of the 21 variables analyzed, 8 showed statistically significant differences on the McNemar Test (p<0.05). Conclusion: interactive play enables hospitalized children to interact in the hospital environment, so that they can express feelings and emotions and it contributes to humanized hospital assistance.

Revisando os efeitos da concentra����o de oxig��nio sobre o desenvolvimento embrion��rio

Despite the fact that the processes of embryo development and implantation of mammals do not occur in atmospheric tension in vivo, it is common practice in laboratories for in vitro fertilization (IVF) the culture of embryos in an oxygen tension of 20%. The discrepancy between the tensions of oxygen leads to important discussions about their effects in vitro embryo development. It is believed that the culture of embryo in atmospheric oxygen tension can be detrimental to the quality of the data for predisposing them to the negative interference of reactive oxygen species (ROS), resulting in oxidative stress, leading to deleterious effects on metabolism embryo gene expression and blastocysts grown in those conditions. Faced with arguments for and against the culture of embryos in vitro oxygen tensions similar to those found in vivo, this revies article aims to condense and discuss the literature concerning the influence of oxygen tension on the quality of in vitro culture.

Employment, growth and reforms in Jamaica

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Nos gramados do Sul: A sele����o baiana de futebol e o torneio do Centen��rio da Independ��ncia em 1922

This article aims to understand how the participation and performance of the state of Bahia at the I Campeonato Brasileiro de Sele����es (I Brazilian Soccer Championship), also known as the Torneio do Centen��rio (Centenary Championship) in 1922 represented an opportunity for the state to claim a centrality in the formation of a national identity associated with soccer. The tournament was conceived as a draft for the formation of a national soccer team that would participate in the VI Campeonato Sul Americano (VI South American Championship) in Brazil. In addition, the event also came to be regarded as a celebration of the fi rst centenary of the Independence, a date that has encouraged the country to refl ect upon its national identity, as well as to reconsider its insertion in modernity. Bahia did well in the tournament, ensuring the second position. As a result, the local press went on to claim the participation of their athletes in the national team and to criticize the disregard of the states of Rio de Janeiro and S��o Paulo towards the Northern region of the country. The local press would also challenge the policies of the Confedera����o Brasileira de Desportos (Brazilian Sports Confederation), the CBD, claiming that they favored the Southern states. Moreover, for the local elites the success of Bahia in the tournament represented the strength and greatness of the state, which gave them the right to claim a greater space and role in the destiny of the country. Finally, the performance of Bahia and its consequences have allowed us to question the limits and peculiarities of the formation of a national identity through the sport, at a moment when the country sought to rethink their identity historically marked by disputes and regional tensions.

Economic relations between Latin America and the European Union

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Challenges for secondary education in Latin America

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The financial and economic crisis of 2008 and its repercussions on economic thought

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