997 resultados para 37:659.3


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Flotation has been widely used in studies of recent foraminifera in order to concentrate tests and save time during picking. In this paper, four flotation agents with different densities were compared: (1) trichloroethylene, TCE (C2HCl3), with a density of 1.46 g mL(-1); (2) sodium nitrate/sodium thiosulfate solution, SNT (NaNO3 + Na2O3S2 center dot 5H(2)O), with a density of 1.46 g mL(-1); (3) zinc chloride Solution, ZC (ZHCl(2)), with a density of 1.70 g mL(-1); and (4) sodium polytungstate solution, SPT (3Na(2)WO(4) center dot 9WO(3) center dot 5H(2)O), with a density of 2.50 g mL(-1). Comparison was carried out by means of qualitative and quantitative data. Results showed that ZC and SPT were the best flotation agents, recovering 91% and 96% of the total tests, respectively, whereas TCE and SNT recovered 59.1% and 72.8%, respectively. Both quantitative and qualitative results significantly improved with a higher density of the flotation liquid. Therefore, substitution of TCE with ZC or SPT solutions is strongly encouraged, because they are, additionally, less harmful to health and the environment. ZC is the most cost-effective, since its results were not significantly different from those of the SPT treatment. Carbon tetrachloride (CCl4) was not considered in this comparative study, because it has been banned in many countries and it is highly harmful to health and the environment.

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We present four new cases of verruciform xanthoma (VX) in the oral mucosa and review the literature. Clinical, histological, and immunohistochemical features of four new cases of VX were analysed together with cases found in a review of the literature. Expression of CD-68 was studied by immunohistochemistry. Only 162 cases were reported in the oral mucosa. Ninety were males (55.5%) and 72 were females (44.5%). Mean age was 44.9 years. The majority of cases occurred in masticatory mucosa (69.7%). Our cases exhibited papillary or verrucous proliferation of squamous epithelium associated with hyperparakeratosis and with numerous foamy cells confined to the lamina propria papillae. Foamy cells were positive to CD-68 antibody, showing a macrophagic nature. VX is a rare benign lesion, and is probably inflammatory. However, its aetiology and pathological mechanisms remain unknown. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

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The family of bismuth titanate, Bi(4)Ti(3)O(12) (BIT) layered-structured ferroelectrics materials is attractive from the viewpoint of such as their application as electronic materials dielectrics, piezoelectrics and pyroelectrics, because they are characterized by good stability of piezoelectric properties, a high Curie temperature and a good resistance vs temperature. Bismuth titanate (Bi(4)Ti(3)O(12)) powders can be prepared using different methods, depending if the creation will be film coating or ceramics. The structure and properties of bismuth titanate materials show a significance dependence on the applied synthesis method. In this review paper, we made an attempt to give an approach to analyszing the structure, synthesis methods and properties of bismuth titanate ferroelectrics materials.

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Preliminary tests indicated 20-degrees-25-degrees-C as optimum temperature range to the germination of the seeds of P. gonoacantha. Seeds germinate both under light and dark conditions, although final percentage is always higher in latest condition. The transmission spectrum of the tegument was investigated and showed an enrichment of the light in far-red region which reaches the embryo. Consequently the white light inhibits partially germination. Another factor controlling germination was the water availability. Our results indicated that the excessive water available during imbibition inhibits the germination process. According to our results we propose that this species do not have a pioneer behavior and even though P. gonoacantha had been described as a riparian vegetation species, the germination process is strongly inhibited with excessive water during imbiibition process.

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The effect of treatment of seeds of Oryza sativa L. cv. IAC 165 with gibberellic acid, 6-benzyladenine and ethrel on the tolerance to the water stress were analysed. Gibberellic acid had no effect and 6-benzyladenine and ethrel promoted slight increase in the tolerance to water stress, specially in darkness. After scarification, those growth regulator presented no effect. Our results suggest that 6-benzyladenine and ethrel promoted water stress tolerance due to the decrease in the resistance of the seed coat to embryo expansion.

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A floristic survey for the family Orchidaceae was undertaken in a coastal forest area of ca. 8 km2 in the Picinguaba Development Center of the Serra do Mar State Park, in the municipality of Ubatuba, Brazil. The sampling used all tracks and roads of the area, up to the altitude of 50 m.s.m. and resulted in 77 species distributed in 45 genera. The spacial distribution of the species was plotted in maps of the nine physiognomical units identified for the area, based on 1:8.000 and 1:25.000 aerial photographs, and field observations. The results are shown in 1:10.000 topographic charts. Ninety percent of the species occur in at least 3 physiognomical units while 60% only occurred in a single unit, what indicates that the orchids can be used to characterize the vegetation even in large scales.

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Litter production was measured for two years (november 1986 to october 1988) in a 29 year -old Pinus elliottii var. elliottii stand in differents resin treatments. Needle production comprised 9 to 93% of total litter fall, while the other categories (branches, barks, seeds and cones) were not significant. Maximum litterfall occurred in march to may 1987 (autumn) and the minimum was in august 1988 (winter) for all treatments and the control. No relationship appeared between annual litterfall and environmental factors, although there was a tendence to exhibit two periods of production: one in summer and other in winter. The results showed that in two years of resin extraction was not sufficient in interfering the litter fall and consequently the productivity.

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Annual and monthly quantities of nutrients wich returned to the soil through litter fall in Pinus elliottii Engelm. var. elliottii stand were estimated durint a two years period, in Experimental Station of Mogi-Guacu, SP. From the trees of the stand was extracted oleoresin according two differents techniques and control. The annual average of nutrients that returned to the soil was 72.2 Kg/ha, in following order: N > Ca > K > Mg > P. No relationship appeared between nutrient concentrations plus quantities when they were compared with oleoresin yields treatments and control. The differences in annual quantities were possibly due to climatic factors. The soil profile showed short concentrations in nutrient contents. Thus, the forest may be suffering by nutrient deficiences.

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Purpose: The purpose of the current study was to evaluate different approaches for bonding composite to the surface of yttria stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics.Methods: One hundred Y-TZP blocks were embedded in acrylic resin, had the free surface polished, and were randomly divided into 10 groups (n=10). The tested repair approaches included four surface treatments: tribochemical silica coating (TBS), methacryloxydecyldihidrogenphosphate (MDP)-containing primer/silane, sandblasting, and metal/zirconia primer. Alcohol cleaning was used as a "no treatment" control. Surface treatment was followed by the application (or lack thereof) of an MDP-containing resin cement liner. Subsequently, a composite resin was applied to the ceramic surface using a cylindrical mold (4-mm diameter). After aging for 60 days in water storage, including 6000 thermal cycles, the specimens were submitted to a shear test. Analysis of variance and the Tukey test were used for statistical analyses (alpha=0.05).Results: Surface treatment was a statistically significant factor (F=85.42; p<0.0001). The application of the MDP-containing liner had no effect on bond strength (p=0.1017). TBS was the only treatment that had a significantly positive effect on bond strength after aging.Conclusion: Considering the evaluated approaches, TBS seems to be the best surface treatment for Y-TZP composite repairs. The use of an MDP-containing liner between the composite and Y-TZP surfaces is not effective.

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The objective of this study was to characterize the fish farms located in the lowland micro region in Cuiaba, MT, through interviews with 26 selected farmers which represent the universe of fish farms that are active. Qualitative data were subjected to statistical Chi-square test to diagnose the existence of correlation between them with 95% confidence. These results support the conclusion that the species that compose the group of round fish are present in 100% of fish farms, accounting 88.2% of production. The difference is that production exclusively in nurseries and the largest area of shallow water, with production in higher scale than elsewhere in the country, with prospects of growth in area and productivity. Some actions should be implemented: legislation objectively and with sufficient qualified personnel to inspect the enterprises, applied research in food management and feed production with better price and quality, technical and administrative management, use of juveniles with proven genetics and monitoring of water quality. Fish farming is the main source of income funding for 67.5% of farmers interviewed. The size of the fish farms did not affect the variables related to implementation, conduct and management of the activity. The demand and price of feed are the variables that most directs the decision making of farmers. The main marketing channel used by medium and large farmers is exclusively, the slaughterhouses. The main part of fish is sold processed.

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This study was designed to evaluate retrospectively the frequency and etiology of the gastrointestinal (GI) lesions in 45 consecutive necropsies of adult patients with Acquired Immunodeficiency Syndrome (AIDS). Gross descriptions and histological sections of the GI tract, from mouth to anus, were reviewed. The slides were H&E stained, and when necessary special stains and immunohistochemical methods were also employed. There were lesions in GI tract in 37 (82.3%) patients; the mouth was the segment most frequently involved (73.3% of the cases), followed by the colon (55.5%). Multiple lesions occurred in 17 (37.7%) cases. Cytomegalovirus caused colonic lesions in 35.7% of the cases. Candidiasis was observed in 26.6% mainly in the mouth and herpes simplex (8.8%) was the important agent of esophageal lesions. Oral hairy leukoplasia associated with HPV was found in 16 (35.5%) cases. Neoplasia was diagnosed in 7 (15.5%) cases: four Kaposi's sarcoma, two anal intramucosal carcinomas and one gastric lymphoma. Our data confirm the high frequency and variety of GI tract alterations in AIDS.