Universal aspects of light halo nuclei

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

Some aspects of the dynamics of fictitious Earth's satellites

In this work we study the dynamics of fictitious satellites of the Earth. In the first part we do not consider the effect of the Moon and study the dynamics in the restrict three-body model, i.e., a massless satellite under the effect of the gravitational force of an oblate Earth and that of the Sun. We show that a satellite starting with an almost circular orbit suffers very large variations of eccentricity, depending on the initial inclination of the orbit with respect to the reference plane. As the eccentricity may be driven to very large values (approximate to0.9) mutual collisions between satellites or collisions with the planet may occur. In the second part, we include the gravitational effect of the Moon. In this case, we find two regions with large variations of eccentricity due to the presence of the Moon. Consequently, in both scenarios, we find some large regions of the phase space where the long-term stability of some fictitious Earth's satellites is not possible. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Experimental aspects of biomass fuels in a bubbling fluidized bed combustor

This work presents experimental information relevant to the combustion of biomass in a bubbling fluidized bed. The biomass distribution in a fluidized bed was studied through tests performed in a cold bed, while the volatiles released in the biomass pyrolysis, the burning rate of the resulting charcoal, and the combustion control regime, were studied through tests performed in a high temperature bed.Visual examination of photographs taken from a transparent walls bed, with a rectangular cross-section, showed that the large fuel particles, typical of biomass processing, were distributed in the bubbles, in the splash zone, and in the emulsion phase. The occurrence of biomass in the emulsion phase was favored by burning biomass particles of greater density and smaller size-expetimentally determined in each case. Decreasing the fuel particle size improved the biomass distribution inside the bed. The same was accomplished by increasing the superficial gas velocity as high as possible, compatibly with the acceptable elutriation.Burning tests showed that the biomass fuels have the advantage of reaching the diffusional regime at temperatures that can be lower than 1000 K, which ensures that the biomass fuels burn in a stable regime. (C) 2007 Elsevier B.V. All rights reserved.

Epidemiological aspects of astrovirus and coronavirus in poults in the South Eastern Region of Brazil

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

Immunologic aspects of West syndrome and evidence of plasma inhibitory effects on T cell function

OBJETIVO: O objetivo deste estudo foi determinar o perfil da deficiência imune em um grupo bem definido de epilepsia: crianças com síndrome de West (SW) e seus padrões EEG de evolução, idade-dependentes, como os complexos onda-aguda- onda lenta generalizadas da síndrome de Lenox-Gastaut (SLG) e as pontas multifocais independentes (PMI). MÉTODO: Um grupo de 50 crianças, 33 com SW, 10 com SLG, 7 com PMI e 20 crianças sadias (controle) foram avaliadas em relação aos seguintes parâmetros:determinação de subpopulações de linfócitos T (CD1, CD3, CD4 e CD8), relação CD4/CD8 e resposta proliferativa de linfócitos frente a fitohemaglutinina (PHA), na presença de plasma autólogo ou de plasma AB (homólogo). A prova cutânea de sensibilização ao Dinitroclorobenzeno (DNCB) foi realizada apenas nos pacientes. Os níveis séricos de IgG, IgA e IgM foram comparados aos valores normais em crianças Brasileiras, em diferentes faixas etárias. RESULTADOS: A resposta ao DNCB foi ausente ou fracamente reativa em 76% dos pacientes. Níveis séricos elevados de IgG (45,7%) e de IgM (61,4%) e baixos de IgA (23,9%) foram detectados nos pacientes. A determinação das subpopulações de linfócitos T em sangue periférico mostrou: deficiência nas proporções de células CD3+ (p<0,05) e de CD4+ (p<0,05), aumento de CD8+ (p<0,01) e diminuição da relação CD4 / CD8 (p<0,001). A proporção de células CD1+ no grupo controle manteve-se menor que 3%, enquanto que em 18% dos pacientes esses níveis variaram entre 3 e 11%. A resposta proliferativa de linfócitos frente a PHA revelou índices blastogênicos significativamente mais baixos apenas quando células dos pacientes foram cultivadas na presença do próprio plasma (plasma autólogo). Quando estas células foram cultivadas na presença de plasma AB, não se evidenciou diferença significativa em relação ao grupo controle. CONCLUSÃO: A imunodeficiência na SW caracterizou-se por: anergia, alteração de imunidade mediada por células e dos níveis de imunoglobulinas, presença de timócitos imaturos na circulação periférica e deficiência funcional de linfócitos T induzida por fatores plasmáticos inibidores. Discutem-se as principais evidências de disfunção imune como imunodeficiência e autoimunidade.

Description of an injury in a human caused by a false tocandira (Dinoponera gigantea, Perty, 1833) with a revision on folkloric, pharmacological and clinical aspects of the giant ants of the genera Paraponera and Dinoponera (sub-family Ponerinae)

A partir de um acidente causado pela picada de uma formiga falsa tocandira na mão de um pescador amador, os autores descrevem os achados clínicos locais observados, tais como edema, eritema e dor excruciante e a evolução do envenenamento, que cursou com fenômenos sistêmicos imediatos, como sudorese fria, náuseas, vômitos, mal estar, taquicardia e linfadenopatia axilar à esquerda. Após três horas, a dor intensa persistia e o paciente apresentou um episódio de hematoquesia, sem história anterior de enfermidades do trato digestivo, hematológicas ou vasculares. O uso de analgésicos (Tramal® 300 mg/dia), água quente e gelo não melhorou a dor, que arrefeceu em oito horas, tendo permanecido por cerca de 24 horas. São apresentados ainda os aspectos folclóricos, farmacológicos e clínicos relacionados às picadas de tocandiras.

Effect of thermal conditioning during embryonic development on aspects of physiological responses of broilers to heat stress

The purpose of the present study was to investigate the effect of thermal conditioning, (through exposure to heat stress), during pre-hatch development on some physiological responses of post-hatch broilers to a post-natal heat stress challenge. Exposure to heat stress at this stage, we hope, may possibly induce epigenetic heat adaptation. Incubating eggs were exposed to temperature of 39.0degreesC for 2 h from Day 13 to 17 of incubation. At 33, 35, 37, 39, 41 and 43 d of age, the broilers hatched from these eggs were housed individually in open-circuit respiration cells. The climatic chambers were set to 22degreesC and increased to 30degreesC for 4 h. O-2 consumption and CO2 production of each chicken was monitored continuously in order to calculate the heat production. Blood samples were obtained before and during the 4 h heat stress. Thermal conditioning during incubation did not affect the plasma T-4, corticosterone, glucose, uric acid and CK concentrations. Temperature challenge, decreased plasma T-3 of broilers of both groups but the decrease was greater in pre-conditioned broilers compared with controls. A similar trend was observed for triglycerides. These changes did not affect total heat production. Since decreased T3 and triglyceride levels are part of the mechanisms for thermoregulation, these suggest that thermal conditioning during incubation can improve the broiler chicken capability for thermotolerance at later post-hatch age. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Morpho-anatomical aspects of Paepalanthus hilairei Koern (Eriocaulaceae) from Serra do Cipo MG

The morphological characteristics of seedlings and the anatomical characteristics of vegetative organs and floral scape of P. hilairei (Eriocaulaceae) were analyzed to investigate the ecological and taxonomic implications for the species. P. hilairei is a perennial plant with an aerial stem and it grows in recently decomposed stony, sandy soils of the Serra do Cipo, in the State of Minas Gerais, Brazil. It is found both on wet and dry soils, exposed to constant winds, high light intensities and extreme daily fluctuations of temperature. The results show that the seeds have operculum and the initial seedling development stages are the same for other Eriocaulaceae. During the germination period, the undifferentiated axis of the embryo becomes apparent. The observation of the development of this axis, shows first, the growth of the leaves and later that of the adventitious root. Attention is focused on the apical stem region which presents sterelis lateral branching with adventitious roots in its base which will develop into paraclades (system of florescences). Both of them rise out of the pericycle and characterize its vegetative growth. The occurrence of a special leaf substomatal chamber may be related to an efficient protection for the gaseous exchange and may be considered an important characteristic of the Eriocaulaceae.

Ultrastructural aspects of acid phosphatase activity in Malpighian tubules of Triatoma infestans Klug

Acid phosphatase activity was investigated ultrastructurally in Malpighian tubules of Triatoma infestans. Enzyme activity was demonstrated in laminated 'concretions' (distal cells) and in typical lysosomes, as well as in basal plasmalemma infoldings and basement membranes (especially in distal cells). This activity was assumed to be related to the excretory functions carried out mostly by the distal cells. Heterochromatin-nucleolus functional relationships involving RNA transcription may promote the nuclear reaction verified in the proximal cells and in some distal cells. A lead phosphate precipitate appeared free in the cytoplasm encircling the nuclei and was assumed to be a contamination from the nuclear precipitates.

Kinetic aspects of ion exchange in KhFek[Fe(CN)(6)](l)center dot mH(2)O compounds: A combined electrical and mass transfer functions approach

The present paper quantifies and develops the kinetic aspects involved in the mechanism of interplay between electron and ions presented elsewhere(1) for KhFek[Fe(CN)(6)](l)center dot mH(2)O (Prussian Blue) host materials. Accordingly, there are three different electrochemical processes involved in the PB host materials: H3O+, K+, and H+ insertion/extraction mechanisms which here were fully kinetically studied by means of the use of combined electronic and mass transfer functions as a tool to separate all the processes. The use of combined electronic and mass transfer functions was very important to validate and confirm the proposed mechanism. This mechanism allows the electrochemical and chemical processes involved in the KhFek[Fe(CN)(6)](l)center dot mH(2)O host and Prussian Blue derivatives to be understood. In addition, a formalism was also developed to consider superficial oxygen reduction. From the analysis of the kinetic processes involved in the model, it was possible to demonstrate that the processes associated with K+ and H+ exchanges are reversible whereas the H3O+ insertion process was shown not to present a reversible pattern. This irreversible pattern is very peculiar and was shown to be related to the catalytic proton reduction reaction. Furthermore, from the model, it was possible to calculate the number density of available sites for each intercalation/deintercalation processes and infer that they are very similar for K+ and H+. Hence, the high prominence of the K+ exchange observed in the voltammetric responses has a kinetic origin and is not related to the amount of sites available for intercalation/deintercalation of the ions.

Phylogenetic and evolutionary aspects of Paracoccidioides brasiliensis reveal a long coexistence with animal hosts that explain several biological features of the pathogen

The habitat of the mycelial saprobic form of Paracoccidio ides brasiliensis, which produces the infectious propagula, has not been determined and has proven difficult for mycologists to describe. The fungus has been rarely isolated from the environment, the disease has a prolonged latency period and no outbreaks have been reported. These facts have precluded the adoption of preventive measures to avoid infection. The confirmation of natural infections in nine-banded armadillos (Dasypus novemcinctus) with P. brasiliensis, in high frequency and wide geographic distribution, has opened new avenues for the study and understanding of its ecology. Armadillos belong to the order Xenarthra, which has existed in South America ever since the Paleocene Era (65 million years ago), when the South American subcontinent was still a detached land, before the consolidation of what is now known as the American continent. on the other hand, strong molecular evidence suggests that P. brasiliensis and other dimorphic pathogenic fungi - such as Blastomyces dermatitidis, Coccidioides immitis and Histoplasma capsulatum - belong to the family Onygenaceae sensu Into (order Onygenales, Ascomycota), which appeared around 150 million years ago.P. brasiliensis ecology and relation to its human host are probably linked to the fungal evolutionary past, especially its long coexistence with and adaptation to animal hosts other than Homo sapiens, of earlier origin. Instead of being a blind alley, the meaning of parasitism for dimorphic pathogenic fungi should be considered as an open two-way avenue, in which the fungus may return to the environment, therefore contributing to preserve its teleomorphic (sexual) and anamorphic (asexual) forms in a defined and protected natural habitat. (c) 2006 Elsevier B.V. All rights reserved.

Morphological and quantitative aspects of nodule formation in hemolymph of the blowfly Chrysomya megacephala (Fabricius, 1794)

Insects manifest effective immune responses that include both cellular and humoral components. Morphological and quantitative aspects of cellular and Immoral cooperation during nodule formation in Chrysomya megacephala hemolymph against Saccharomyces cerevisae yeast cells were demonstrated for the first time. The analyses were performed in non-injected larvae (NIL), saline-injected larvae (SIL) and yeast-injected larvae (YIL). The hemolymph of injected groups was collected 0.5, 1, 2, 4, 12, 24, 36, or 48-h post-injection. Morphological aspects of YIL nodulation were investigated using transmission electron microscopy (TEM). Quantitative analyses consisted of total (THC) and differential hemocyte counts (DHC) in all the groups and total yeast count (TYC) in YIL, which were performed in an improved Neubauer chamber. Nodule formation was initiated at approximately 2-h post-injection. Twelve hours after the injection, TEM revealed the presence of an amorphous membrane, at the same time that circulating hemocyte number decreased significantly contrasting the increase of yeast number. Our results showed the ability of C megacephala hemolymph to perform humoral encapsulation when hemocyte population is insufficient to eliminate the microorganisms, warranting consideration in future investigations on the relative roles played by cellular and humoral elements of innate immunity of this calliphorid. (c) 2007 Elsevier B.V. All rights reserved.

Ultrastructural and morphometric aspects of ageing in the retinal capillaries of rats

Age-related morphological, ultrastructural and morphometric changes in the capillaries of the superficial and deep plexuses of the rat retina were studied in animals aged from 3 to 15 months. Our results suggest that age-related morphological alterations start occurring in the retina of rats at about 12 months of age. Increased glycogen deposits, pinocytotic vesicles, residual bodies and cell debris were observed in both the endothelial and pericytic cells of 12- and 15-month-old animals. In addition, heterogeneous osmiophilic accumulations, electron-transparent spaces were observed in the basement membrane as well as projections of the basement membrane towards the neighboring cells. Morphometric examination of the two vascular plexuses studied did not show differences in the area of the endothelial or pericytic cells, basement membrane or vascular lumen between rats of different ages.

Aspects of IFP for citrus production in Brazil

Brazilian citriculture represents about 25% of the total world citrus production with an area of 851,518 ha and a total production of more than 17 million tons in 1996. Besides its importance to the brazilian economy, represented by more than 1 billion US $ by year from FCOJ exportation, the citriculture has problems related to low productivity, due to several cultural practices and management. The productivity would be improved by an IFP system. The main problems are related to soil, as poor conservation, use of poor drained soils and bad preparation for planting; diseases-canker, CVC, leprosis, Phytophtora gummosis and other fungus diseases; pests - mites, scales, nematodes and others; the use of disease free and improved scion and rootstocks propagative material is usual; cultural practices - as nutrition, irrigation, wind breaks, weed control, pruning, replant and others, as density planting could be improved. Some possible solutions will be discussed for improving the brazilian citrus productivity and quality by IFP, based on research made.

Morphological aspects of Culex quinquefasciatus salivary glands

The salivary glands of Culex quinquefasciatus female mosquitoes are paired organs composed of two lateral lobes with proximal and distal secretory portions, and a medial lobe. All portions comprise a simple epithelium that surrounds a salivary duct. In the apical portion of the medial lobe, non-secretory cells strongly resemble cells involved in ion and water transport. The general architecture of the secretory portions is similar between lobes. The appearance of the secretory material and the morphological aspect of the apical cell membrane are the most distinctive features among the three secretory portions. Cells in the lateral proximal lobe display thin membrane projections extending into a translucent and finely filamentous secretory product. At the lateral distal portion, the apical cell membrane forms an intricate meshwork that encloses a dark secretory product. Medial lobe secretory cells also contain secretory cavities surrounded by intracytoplasmic vesicles, all containing a very dark and uniform product. Scattered cells holding numerous vacuoles, some of them containing a small and electron-dense granule eccentrically located and resembling those of the diffuse endocrine system, are frequently observed in the periphery of all secretory portions. Immunofluorescence assays revealed that the distal portion of the lateral lobes contains apyrase, an enzyme putatively responsible for platelet aggregation inhibition, diffusely distributed in the cell cytoplasm. © 2003 Elsevier Ltd. All rights reserved.