Hyperplasia of elastic tissue in hepatic schistosomal fibrosis

Elastic tissue hyperplasia, revealed by means of histological, immunocytochemical and ultrastructural methods, appeared as a prominent change in surgical liver biopsies taken from 61 patients with schistosomal periportal and septal fibrosis. Such hyperplasia was absent in ecperimental murine schistosomiasis, including mice with "pipe-stem" fibrosis. Displaced connective tissue cells in periportal areas, such as smooth muscle cells, more frequently observed in human material, could be the site of excessive elastin synthesis, and could explain the differences observed in human and experimental materials. Elastic tissue, sometimes represented by its microfibrillar components, also appeared to be more condensed in areas of matrix (collagen) degradation, suggesting a participation of this tissue in the remodelling of the extracellular matrix. By its rectratile properties elastic tissue hyperplasia in hepatic schistosomiasis can cause vascular narrowing and thus play a role in the pathogenesis of portal hypeertension.

Dynamic of population-dynamics in a medically important snail species Lymnaea (Radix) Luteola (Lamarck)

The life-cycle parameters of the snail Lymnaea (Radix) luteola and the factors influencing the same have been studied under laboratory conditions. Ins each month, from July 1990 to June 1991, a batch of 100 zero-day old individual were considered for studies. The snails of April batch survived for 19.42 days while those in December batch survived for 87.45 days. The May batch individual though survived for 65.67 days gained maximum shell size (15.84 mm in length) and body weight (419.87 mg). All individuals of April batch died prior to attainment of sexual maturity. In the remaining 11 batches the snails became sexually mature between 32 and 53 days. At this stage, they were with varying shell lengths, 9.3 mm to 13,11 mm in respect to batches. The reproduction period varied from 1-67 days. An individual laid, on an average, 0,25 (March batch) to 443.67 (May batch) eggs in its life-span. A batch of such snails would leave 24312, 22520, 720268, 80408, 76067, 418165, 214, 9202, 0, 0, 2459386 and 127894 individuals at the end of 352nd day. Since the environmental conditions were almost similar the 'dynamic' of population dynamics seems to be involved with the 'strain' of the snail individuals of the batches concerned.

The generation and re-generation of social capital and enterprises in multi-stakeholders social cooperative enterprises: a system dynamic approach

Theories on social capital and on social entrepreneurship have mainly highlighted the attitude of social capital to generate enterprises and to foster good relations between third sector organizations and the public sector. This paper considers the social capital in a specific third sector enterprise; here, multi-stakeholder social cooperatives are seen, at the same time, as social capital results, creators and incubators. In the particular enterprises that identify themselves as community social enterprises, social capital, both as organizational and relational capital, is fundamental: SCEs arise from but also produce and disseminate social capital. This paper aims to improve the building of relational social capital and the refining of helpful relations drawn from other arenas, where they were created and from where they are sometimes transferred to other realities, where their role is carried on further (often working in non-profit, horizontally and vertically arranged groups, where they share resources and relations). To represent this perspective, we use a qualitative system dynamic approach in which social capital is measured using proxies. Cooperation of volunteers, customers, community leaders and third sector local organizations is fundamental to establish trust relations between public local authorities and cooperatives. These relations help the latter to maintain long-term contracts with local authorities as providers of social services and enable them to add innovation to their services, by developing experiences and management models and maintaining an interchange with civil servants regarding these matters. The long-term relations and the organizational relations linking SCEs and public organizations help to create and to renovate social capital. Thus, multi-stakeholder cooperatives originated via social capital developed in third sector organizations produce new social capital within the cooperatives themselves and between different cooperatives (entrepreneurial components of the third sector) and the public sector. In their entrepreneurial life, cooperatives have to contrast the "working drift," as a result of which only workers remain as members of the cooperative, while other stakeholders leave the organization. Those who are not workers in the cooperative are (stake)holders with "weak ties," who are nevertheless fundamental in making a worker's cooperative an authentic social multi-stakeholders cooperative. To maintain multi-stakeholder governance and the relations with third sector and civil society, social cooperatives have to reinforce participation and dialogue with civil society through ongoing efforts to include people that provide social proposals. We try to represent these processes in a system dynamic model applied to local cooperatives, measuring the social capital created by the social cooperative through proxies, such as number of volunteers and strong cooperation with public institutions. Using a reverse-engineering approach, we can individuate the determinants of the creation of social capital and thereby give support to governance that creates social capital.

Mosquito community composition in dynamic landscapes from the Atlantic Forest biome (Diptera, Culicidae)

Mosquito community composition in dynamic landscapes from the Atlantic Forest biome (Diptera, Culicidae). Considering that some species of Culicidae are vectors of pathogens, both the knowledge of the diversity of the mosquito fauna and how some environment factors influence in it, are important subjects. In order to address the composition of Culicidae species in a forest reserve in southern Atlantic Forest, we compared biotic and abiotic environmental determinants and how they were associated with the occurrence of species between sunset and sunrise. The level of conservation of the area was also considered. The investigation was carried out at Reserva Natural do Morro da Mina, in Antonina, state of Paraná, Brazil. We performed sixteen mosquito collections employing Shannon traps at three-hour intervals, from July 2008 to June 2009. The characterization of the area was determined using ecological indices of diversity, evenness, dominance and similarity. We compared the frequency of specimens with abiotic variables, i.e., temperature, relative humidity and pluviosity. Seven thousand four hundred ten mosquito females were captured. They belong to 48 species of 12 genera. The most abundant genera were Anopheles, Culex, Coquillettidia, Aedes and Runchomyia. Among the species, the most abundant was Anopheles cruzii, the primary vector of Plasmodium spp. in the Atlantic Forest. Results of the analyses showed that the abiotic variables we tested did not influence the occurrence of species, although certain values suggested that there was an optimum range for the occurrence of culicid species. It was possible to detect the presence of species of Culicidae with different epidemiologic profiles and habitat preference.

Carbon balance and crop residue management in dynamic equilibrium under a no-till system in Campos Gerais

The adoption of no-tillage systems (NT) and the maintenance of crop residues on the soil surface result in the long-term increase of carbon (C) in the system, promoting C sequestration and reducing C-CO2 emissions to the atmosphere. The purpose of this study was to evaluate the C sequestration rate and the minimum amount of crop residues required to maintain the dynamic C equilibrium (dC/dt = 0) of two soils (Typic Hapludox) with different textural classes. The experiment was arranged in a 2 x 2 x 2 randomized block factorial design. The following factors were analyzed: (a) two soil types: Typic Hapludox (Oxisol) with medium texture (LVTM) and Oxisol with clay texture (LVTA), (b) two sampling layers (0-5 and 5-20 cm), and (c) two sampling periods (P1 - October 2007; P2 - September 2008). Samples were collected from fields under a long-term (20 years) NT system with the following crop rotations: wheat/soybean/black oat + vetch/maize (LVTM) and wheat/maize/black oat + vetch/soybean (LVTA). The annual C sequestration rates were 0.83 and 0.76 Mg ha-1 for LVTM and LVTA, respectively. The estimates of the minimum amount of crop residues required to maintain a dynamic equilibrium (dC/dt = 0) were 7.13 and 6.53 Mg ha-1 year-1 for LVTM and LVTA, respectively. The C conversion rate in both studied soils was lower than that reported in other studies in the region, resulting in a greater amount of crop residues left on the soil surface.

Elastic stresses and plastic deformations in 'Santa Clara' tomato fruits caused by package dependent compression

The objective of this work was to study the fruit compression behavior aiming to develop new tomato packages. Deformations caused by compression forces were observed inside packages and in individual 'Santa Clara' tomato fruit. The forces applied by a transparent acrylic lever to the fruit surface caused pericarp deformation and the flattened area was proportional to the force magnitude. The deformation was associated to the reduction in the gas volume (Vg), caused by expulsion of the air from the loculus cavity and reduction in the intercellular air volume of the pericarp. As ripening advanced, smaller fractions of the Vg reduced by the compressive force were restored after the stress was relieved. The lack of complete Vg restoration was an indication of permanent plastic deformations of the stressed cells. Vg regeneration (elastic recovery) was larger in green fruits than in the red ones. The ratio between the applied force and the flattened area (flattening pressure), which depends on cell turgidity, decreased during ripening. Fruit movements associated with its depth in the container were observed during storage in a transparent glass container (495 x 355 x 220 mm). The downward movement of the fruits was larger in the top layers because these movements seem to be driven by a summation of the deformation of many fruits in all layers.