Structural and ultrastructural characterization of the embryonic development of Pseudoplatystoma spp. hybrids

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

Duration of Protopolybia exigua exigua (de Saussure) nests and related aspects as influenced by phorid fly infestation (vespidae, polistinae, epiponini)

The main characteristics of 55 nests of Protopolybia exigua exigua were periodically evaluated in Ribeirão Preto, southeastern Brazil. Although the queens' life-span can eventually reach one year, nests barely thrive for six months because most of them are periodically invaded by the scavenger phorid fly, Megaselia aff. picta. Under heavy infestation the adult wasp population partially closes the nest entrance, migrates and constructs a new nest in the neighborhood. Afterwards the old-nest's entrance can be completely closed by the wasps which results in blocking the parasitoid flies inside. In the tropics, predation by ants is considered the main selective pressure which shaped most of the bionomic characteristics of Polistinae wasps. It is suggested that Megaselia can easily overcome the usual wasps defensive tactics just because they are so specialized against ants. Aerial raids, fast erratic-jerking movements, rapid and efficient oviposition behavior, etc. can eventually turn Megaselia into a very important enemy of some social wasps.

Comparação de métodos para determinar biomassa na região amazônica

The aboveground biomass content of a region can be estimated by either direct or indirect methods. Direct methods correspond to the biomass content determination with scales and extrapolation of results to larger areas. It is a destructive and very laborious procedure. Indirect methods utilize formulas whose entrance parameters are obtained from forest inventories. Forest inventories are made with the purpose to plan exploration and land use and the inventory data are frequently not suitable for biomass estimation. Problems with both methods increase in the Amazon region, where little information is available on forest biomass. The objective of this paper is to establish, by comparing the application of the indirect and direct methods in the determination of the biomass, the more appropriate indirect formulation to represent the characteristic vegetation of a region in the amazonian forest. A 0.2 hectare area was chosen, which was part of a major forest clearing experiment conducted in Tomé Açu, a town located 250 km south of Belém, the capital of the Brazilian state of Pará. The entire biomass in the area was weighted with scales during the three weeks that followed the cut of the forest in July 1994. A detailed inventory was carried out in the area and then the indirect method was applied in the data. Seven different formulas for determining biomass were used. Comparison of the data of real mass and the mass obtained through the application of the seven formulas indicated that the more suitable for the region is given by FW = α · φβ · Hγ, where FW is total fresh weight (kg), φ is the diameter at breast height (cm), H is the total height of the tree and α, β and γ are regression coefficients (equal to 0.026, 1.529 and 1.747, respectively).

In vivo antimicrobial activity of 2% chlorhexidine used as a root canal irrigating solution

The aim of the present study was to evaluate the in vivo antimicrobial activity of 2% chlorhexidine gluconate (FCFRP-USP) used as a root canal irrigating solution in teeth with pulp necrosis and radiographically visible chronic periapical reactions. Culture techniques and measurement of the inhibition zone were used. Twenty-two root canals of incisors and molars of 12 patients were used. After accessing the canal, the first root canal sample was collected with two sterile paper points that were transferred to a tube containing reduced transport fluid. The root canal was instrumented using chlorhexidine solution. A small sterile cotton pellet was placed at the root canal entrance, and the cavity was sealed with zinc oxide-eugenol cement. The canals were maintained empty for 48 h. Three sterile paper points were then introduced to absorb the root canal fluid (second sample). One paper point was placed on an agar plate inoculated with Micrococcus luteus ATCC 9341 and incubated for 24 h at 37°C, and the other two were submitted to microbiological evaluation. Present in 10 cases at baseline, mutans streptococci was reduced by 100% at the second assessment. Treatment showed an efficiency of 77.78% for anaerobic microorganisms at the second assessment. These data suggest that chlorhexidine prevents microbial activity in vivo with residual effects in the root canal system up to 48 h. Copyright © 1999 by The American Association of Endodontists.

Spatial and temporal heterogeneity in the Jurumirim Reservoir, São Paulo, Brazil

Jurumirim is a large tropical reservoir with remarkable spatial gradients. This structure seems to be determined by a longitudinal gradient in the trophic conditions along the main axis of the reservoir. Nutrient-rich waters enter from the main tributary river, Paranapanema, and towards the dam there is a lacustrine zone that is deeper and more oligotrophic. Additional variability is derived from two important lateral components: the entrance of the Taquari River, the second largest tributary, bringing waters with higher pH and alkalinity; and the Ribeirão das Posses arm, a sheltered bay where the hydrodynamic conditions promote a high growth of phytoplankton. However, such a spatial pattern is not static. It can become either more defined, during the dry season (late autumn and winter), or less evident, during the expansion of the lotic conditions in the rainy period (late spring and summer). Seasonal processes of stratification/destratification determine the temporal changes in the lacustrine zone but, unlike the upstream regions, the dam zone of the reservoir seems to be little affected by periodic pulses of modifications produced by intensive rains. The presence of extensive wetlands and oxbow lagoons in the mouth zones of the main rivers also constitutes an important source of spatial variability and should be considered in the future.

Nest architecture and population dynamics of the ponerine ant Ectatomma edentatum (Hymenoptera, Formicidae)

Twelve nests of Ectatomma edentatum (Hymenoptera, Formicidae) were collected from January to December 1996, in Rio Claro, SP, southeastern Brazil. This species excavates their nests up to 1, 10m deep, containing 2, 3, or 4 chambers with an entrance hole of up to 5mm diameter. Colonies with 104, 79, and 82 adult ants respectively were found in February, October, and November. These numbers decreased from March. Colonies with 21 and 16 adult ants were observed in May and July. The colonies' populations increased again in August. Immature stages were not seen January, February, and July, but there were many between March-April and September-November. There was no significant correlation between the number of individuals per colony and temperature or between the number of colonies and relative humidity and rainfall.

Behavioral evaluation during dental care in children ages 0 to 3 years

Purpose: Many studies concluded that the behavior of babies complicated dental care because of child immaturity or the difficulty of establishing acceptable communication and comprehension. Methods: The records of 696 babies were randomly selected from the baby clinic of Araçatuba in Brazil. Patient age ranged from 0 to 36 months. They were divided into 6 groups according to age: Group I-0 to 6 months; Group II-7 to 12 months; Group III-13 to 18 months; Group IV-19 to 24 months; Group V-25 to 30 months; Group VI-31 to 36 months. The behavior of the child was evaluated upon entrance in the dental office and during the first 4 clinical appointments with a clinical exam and oral physiotherapy. The baby was classified as collaborator (C) or noncollaborator (NC). Statistical analysis was performed using Pearson's chi-square method (P< .05). Results: The percentage of NC for Groups II, III, IV, and V (66%), was significantly higher than for groups I (30%) and VI (50%). Conclusions: Babies from 0 to 6 months showed a collaborative behavior; babies from 7 to 30 months showed noncollaborative behavior; and babies from 31 to 36 months showed no statistically significant difference between the percentage of C and NC.

External and internal structure of Atta bisphaerica Forel (Hymenoptera: Formicidae) nests

This work was carried out to determine the internal and external structures of Atta bisphaerica (Forel) nests. Six nests were excavated and during excavation, all data referring to chambers and tunnels were recorded. Three nests had been internally cement-moulded, which enabled a better view of the chamber and tunnel structures. Atta bisphaerica nests presented a similar structural pattern, varying only in the number of chambers as a function of external mound area. Chambers were spherical with two communication tunnels. Internal tunnels had an elliptical section, sometimes circular, indirectly linked to chambers through ramifications and directly through short tunnels. Entrance holes were linked to the area of highest chamber concentration by tunnels from the elliptical section, which led to the nest in a radial manner. Knowledge of the colony's three-dimensional architecture permits successful application of chemical control processes, reduces the quantity of product applied, and consequently diminishes costs and environmental damage.

Experimental analysis of heat transfer in packed beds with air flow

Heat-transfer studies were carried out in a packed bed of glass beads, cooled by the wall, through which air percolated. Tube-to-particle diameter ratios (D/dp) ranged from 1.8 to 55, while the air mass flux ranged from 0.204 to 2.422 kg/m2·s. The outlet bed temperature (TL) was measured by a brass ring-shaped sensor and by aligned thermocouples. The resulting radial temperature profiles differed statistically. Angular temperature fluctuations were observed through measurements made at 72 angular positions. These fluctuations do not follow a normal distribution around the mean for low ratios D/dp. The presence of a restraining screen, as well as the increasing distance between the temperature measuring device and the bed surface, distorts TL. The radial temperature profile at the bed entrance (T0) was measured by a ring-shaped sensor, and T 0 showed to be a function of the radial position, the particle diameter, and the fluid flow rate.

Morphology of oesophagus and crop of the partrigde Rhynchotus rufescens (Tiramidae)

Twenty adult partridges Rhynchotus rufescens were used to study the morphology of oesophagus and crop. Materials to the morphologic study were collected and lengths of the oesophagus and of the crop were measured. For histological study, fragments of the oesophagus and of the crop were stained routinely with Masson's trichrome stain. Total oesophagus was larger in females. In the entrance of the thorax, its ventral wall is enlarged broadly, forming the crop, which is larger in males. Oesophagus mucosa is constituted by stratified squamous epithelium, with mucous glands and lymphatic tissues. There are three layers of smooth muscle, involved in serosa. The histological structure of the crop is similar to the oesophagus. The mucous glands are reduced in size and the lymphatic tissues are dispersed in the connective tissue. There is a thin stratum of smooth muscle and other two wider layers of longitudinal and circular musculature.

Root trunk height as a risk factor for periodontal furcation involvement in maxillary first molars: an in vitro study.

The aim of this study was to correlate the root trunk height from the furcation openings on the buccal, mesial and distal surfaces to the cemento-enamel junction in upper first permanent molars in human beings with risk for periodontal disease progression. One hundred extracted maxillary first molars were used. Reference points and demarcations were determined from the entrance of the buccal (F1), mesial (F2) and distal (F3) furcations to the cemento-enamel junction in millimeters. The mean distances found were 3.50 mm, 4.44 mm and 4.26 mm for the buccal, mesial and distal furcations, respectively, in relation to the cemento-enamel junction. The statistical analyses were Student's t-test and Chi-square (X2). With periodontal disease progression, the buccal furcation presents a greater compromising risk due to its proximity to the cemento-enamel junction, while the mesial furcation is the most distant, comprising a lesser risk.

Avaliação energética de um sistema de refrigeração por absorção utilizando gás de aterro e gás natural

The current technological development made by the absorption refrigeration system is an economic and ambient alternative in comparison to the vapor cycle, possessing an advantage that uses thermal energy that is less noble. Chillers of absorption are used widely in the air conditioned industries, because they can be set in motion through hot water vapors that burn natural gas, solar energy, biomasses amongst others instead of electricity. These systems allow it to reduce the tips of electric demand and balance the rocking of energy demand. This work has had a main objective to simulate a absorption refrigeration cycle with lithium-water bromide solution using biogas of sanitary landfill, and mixtures of this with natural gas. These results shown to the energy viability of the system burning biogas and its mixtures with natural gas in the generator, when compared with equipments that uses traditional fuels (natural gas, oil diesel, amongst others), for operation the commercial chillers with 15 kW of the refrigeration capacity and temperature of the water in the entrance of 14°C and the exit of 7°C.

Estimativa da exigência hídrica do amendoim usando um modelo agrometeorológico

In the experimental area of the Department of Environmental Sciences (21.85° S; 48.43° W; 786 m), in the School of Agronomical Sciences, UNESP, Botucatu, SP, an experiment was carried out using peanut (Arachis hypogaea L), cv. IAC-TATU-ST, to quantify the crop daily water requirements. During the peanut crop cycle, the environmental variables, such as rainfall, air temperature, air relative humidity, soil matric potential, soil heat flux and radiation balance, have been registered continually. These measurements were used to calculate the daily crop evapotranspiration, by the Bowen ratio method. The water replacement required by the peanut crop was done the dripping irrigation system, oriented by a dynamic agrometeorological model that computes the entrance and exit of water in the soil. During the peanut crop cycle, 9.0 mm of water was used from sowing to emergence; 67.0 mm of water, in the growth stage; 166.0 mm, in the flowering stage; 124.0 mm in the final stage and 46.0 mm from physiological maturity to harvest. Oot of 412.0 mm of the total consumption, 246.0 mm of water was supplied by irrigation and 166.0 mm by the rain. The grain yield was 3.15 t ha-1 for 15% of humidity, and the water use efficiency was 0.764 kg m-3.

Multi-dimensional effects on Cladoceran (Crustacea, Anomopoda) assemblages in two cascade reservoirs in Southeast Brazil

The Cladocera assemblages in two cascade reservoirs located in the Paranapanema River in Brazil were studied during two consecutive years. Upstream Chavantes Reservoir is an accumulation system, with a long water retention time, high depth and oligo-mesotrophic status. The downstream Salto Grande Reservoir is a small, run-of-river reservoir, with a short water retention time, shallow depth and meso-eutrophic status. The goal of this study was to determine the inter- and intra-reservoir limnological differences with emphasis on the Cladocerans assemblages. The following questions were posed: (i) what are the seasonal dynamics of the reservoir spatial structures; (ii) how dynamics, seasonally, is the reservoirs spatial structure; and (iii) are the reservoir independent systems? A total of 43 Cladoceran species were identified in this study. Ceriodaphnia silvestrii was the most abundant and frequent species found in Chavantes Reservoir, while C. cornuta was most abundant and frequent in Salto Grande Reservoir. The Cladoceran species richness differed significantly among sampling sites for both reservoirs. In terms of abundance, there was a significant variation among sampling sites and periods for both reservoirs. A cluster analysis indicated a higher similarity among the deeper compartments, and the intermediate river-reservoir zones was grouped with the riverine sampling sites. For the smaller Salto Grande Reservoir, the entrance of a middle size tributary causes major changes in the system. A distinct environment was observed in the river mouth zone of another small tributary, representing a shallow environment with aquatic macrophyte stands. A canonical correlation analysis between environmental variables and Cladoceran abundance explained 75% of the data variability, and a complementary factorial analysis explained 65% of the variability. The spatial compartmentalization of the reservoirs, as well as the particular characteristics of the two study reservoirs, directly influenced the structure of the Cladoceran assemblages. The conditions of the lacustrine (dam) zone of the larger Chavantes Reservoir were reflected in the upstream zone of the smaller downstream Salto Grande Reservoir, highlighting the importance of plankton exportation in reservoir cascade systems. The comparative spatial-temporal analysis indicated conspicuous differences between the two reservoirs, reinforcing the necessity of considering tropical/subtropical reservoirs as complex, multi-compartmental water systems. © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Asia Pty Ltd.

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