Germinação de sementes de pinho-cuiabano sob deficiência hídrica com diferentes agentes osmóticos

The species Schizolobium amazonicum (Huber ex Ducke) commonly known as pinho-cuiabano or paricá, is one of the trees in Amazonian area used for plantings in degraded areas, reforestations and agroforestry systems. The present work evaluated the germinative behaviour of seeds of Schizolobium amazonicum in relation to the hydric stress, defining their levels of tolerance to those limitations in the environment. The seeds were collected from 30 trees in Alta Floresta-MT and submitted the dormancy treatment by submersion into water at 100°C for 1 minute; followed by treatment with fungicide Ridomil and Cercobin 0,25% each, then being left to germinate in a BOD camera at 30°C under a photoperiod of 12 hours. For evaluating the effect of different water potentials in the germinative process, polyethylene glicol (PEG 6000) was used and the salts NaCI and CaCl 2 used to simulate saline stress. The seeds were put to soak in potentials of 0 (control); -0.1 ; -0.2; -0.3; -0.4 and -0.5MPa. For each treatment 5 repetitions of 20 seeds were used in gerbox, placed between filter paper moistened with 20 mL of PEG, NaCI and CaCl 2 solutions. The solutions were changed at intervals of 24 hours for maintenance of the potential. The evaluations of percentages and germination speed were carry out daily for 8 days, being considered germinated the seeds that presented a 2mm root extension or longer. The data were submitted to analysis of variance and averages compared by the Tukey test at 5% probability. It was concluded that osmotic potentials between -0.4 and -0.5MPa inhibited the germination of seeds of Schizolobium amazonicum completely. The osmotic stress caused by CaCl 2, and PEG injured the germination more than did the stress caused by NaCl.

Influěncia defluídos biológicos na sobrevivěncia de staphylococus aureus sobre diferentes superficiessecas

It is known that the transmission of hospital infections, whether environmental or cross infection, is facilitated by the enhanced survival of microorganisms on dry surfaces that is caused by the presence of biological fluids. To demonstrate the need for care with bodily substances in the routine of cleaning, this study evaluated the influence of some body fluids (blood, urine and artificial saliva), deposited in the same way on various surfaces and allowed to dry, on the survival of Staphylococcus aureus (ATCC 25923). Blood was able to preserve bacterial viability for up to 72 days when deposited on ceramic flooring. Fabric of cotton fiber allowed longer survival than synthetic fabric. These results show that the composition of biological fluid and type of support influence bacterial survival in normal conditions.

Ensaios biológicos para avaliação de segurança de produtos cosméticos

Despite efforts to the contrary, some cosmetic products can cause undesirable side effects in the users. These may often be due to individual factors or inappropriate use of the product. Thus, biological assays to assess the safety of a new cosmetic must precede its being placed on the market. Historically, these tests have always been carried out in vivo, in animals, since such tests can be used to evaluate many of the potential risks, such as irritation, allergy or systemic effects; but, recently, some research centers have been adopting in vitro alternatives, in order to replace the animal tests. This review emphasizes the need to employ biological assays to test the safety of cosmetic products, and reviews the main in vivo and in vitro tests used, focusing on the need to develop and use alternatives to the in vivo assays of product safety, so as to offer the consumers the maximum safety with the least possible risk, while ensuring the best conditions of use of the product.

Influência dos agentes clareadores na microdureza de resina composta nanoparticulada

Objective: To assess the effect of bleaching agents on the microhardness of nanoparticle resin composite. Methods: Twenty-eight cylindrical test specimens (8× 1mm) of Filtek™ Supreme XT resin (3M/ESPE) were prepared and divided into 5 groups. The initial Vickers microhardness was measured (load of 50 grams force for 30 seconds) on the top surface of the test specimens. The groups were treated and divided as follows: G1 - artificial saliva (21 days - control); G2 - 7% hydrogen peroxide gel applied for 4h/day, for 14 days; G3 - 10% carbamide peroxide for 4h/day, for 14 days: G4 - 35% hydrogen peroxide gel applied in three sessions of 30 minutes each, with an interval of one week (21 days) between the sessions; G5 - 35% carbamide peroxide, three sessions of 30 minutes each, with an interval of one week (21 days) between the sessions. The top surfaces of the test specimens received treatment and were submitted to the Vickers microhardness test. Results: The results obtained were submitted to the Analysis of Variance at a fixed criterion, at a level of significance of p=0.05. No significant differences were observed among the treatments tested (p=0.42) when compared with G1. Significant differences (Tukey test) were found when the initial microhardness values were compared with the values after experimental treatments (p<0.01). Conclusion: The application of bleaching agents did not alter the microhardness of resin composites. Therefore, there is no need to change restorations after bleaching.

La juventud rural del Cono Sur: agentes de cambio y desarrollo, para la superación de la pobreza rural

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Impactos diferenciados de las reformas sobre el agro mexicano: productos, regiones y agentes

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Agentes tróficos na dieta de leitões desmamados sobre a atividade das enzimas digestivas e o desempenho

It was evaluated the effect of the addition of glutamine, polyunsaturated fatty acids or cellular wall of yeast to the diet of weaned pigs on the activity of the pancreatic enzymes (lipase, amylase and trypsin) and the intestinal mucous membrane (dipeptidase, sucrase and maltase) and on the performance. Forty-five weaned pigs were used and distributed in a randomized block design, in factorial outline, with four diets (T1 - basal diet (BD); T2 - BR + 1% glutamine; T3 - BD + 0,2% cellular wall of yeast; T4 - BD + 5% fish oil) and two slaughter ages (seven and 14 days post weaning). The performance was measured in the first two weeks post-weaning. The addition of 1% glutamine in the diet of pigs increased the specific and total activity of the amylase, and total activity of the trypsin in the second week post weaning. The others supplements not change the activity of the digestive enzymes in the pigs. Also an increase was observed in the total activity of the lipase, and specific activity of the trypsin and maltase in function of the age post-weaning. In general, the activities of the digestive enzymes were correlated positively, except for the dipeptidase that was not correlated with any other enzyme. Positive correlation was observed between weight gain and activity of the lipase and of the amylase. The supplements included in the diet not influence the performance of weaned pigs.

Agentes del "desarrollo"

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Folhas de amoreira tratadas com vitamina e esterol e seus efeitos em parâmetros biológicos de Bombyx mori L.

This study aimed to evaluate the effects of adding different concentrations of the leaf additives nandrolone decanoate, ascorbic acid, retinol palmitate and retinol acetate on biological parameters of Bombyx mori larvae. The results showed that nandrolone and ascorbic acid, both at 0.5%, provide the best value for the development of the larvae of B. mori, values which do not correspond to significant increases in cocoon and silk production; 1.0% of retinol palmitate show negative effect to larvae development.

Seleção de agentes alternativos ao ágar para propagação de plântulas de Cattleya loddigesii Lindley (Orchidaceae)

The aim of this study was to evaluate the in vitro growth of Cattleya loddigesii in alternative agents to agar with starch and physical matrix with acclimatization of regenerated plants. Protocorms with 90 days after sowing (0.5 cm of length) were subcultured in 1/2 MS culture medium among the treatments consisting of: agar 7 g L-1 (T1, which corresponds the control), agar 3,5 g L-1 with cassava starch 30 g L-1 (T2), cassava starch 60 g L-1 (T3), cotton fiber (T4) and chopped polyurethane foam (T5). Plantlets were retained in these treatments for over 150 days, and at the end of in vitro culture, were analyzed by their biometric data and acclimatized in a greenhouse during 120 days and evaluated the survival and relative growth rate (RGR). The substrate comprising of chopped polyurethane foam (T5) showed greater efficiency for growth in vitro and also increased survival rate, while substrate cassava starch (T3) provided delay for plantlet growth. Therefore, chopped polyurethane foam is recommended because of low cost and suitable characteristics for the propagation of Cattleya loddigesii.

Desarrollo: imagenes, conceptos, criterios, agentes, opciones

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Agentes extrasectoriales y transformaciones recientes en el agro argentino

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Agentes del "desarrollo"

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El papel de los agentes en las políticas agrícolas: intenciones y realidad

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Influência de uma piscicultura em tanquesrede na dieta e atributos biológicos de Galeocharax knerii na represa de Chavantes, Brasil

The aim of the present study was to evaluate the diet and biological attributes of the population of Galeocharax knerii residing near net cage fish farming activities in the Chavantes reservoir (Paranapanema River, Brazil) to check their possible impacts. Samples were collected from two populations: one near the net cages (NC) and one from an area not influenced by these cages denominated the reference site (RS). Monthly sampling was carried out from March 2008 to February 2009. Fish were caught with a standardized effort using gill nets deployed for 14 hours. The alimentary index (AI) and degree of repletion (RD) were calculated to determine diet composition. Analyses of the sex ratio and the gonadosomatic index (GSI) were also performed. The calculations of AI revealed that fish wastes constituted the most frequent food item in the diet in both study areas (NC = 70.43; RS = 87.55), followed by the consumption of Apareiodon affinis (AI = 29.56), which was abundant near the NC, and prawn at the reference site (AI = 12.28). The sex ratio differed from 1:1 and mature individuals were only found in the population near the NC. The findings demonstrate that G. knerii indirectly benefits from the input of organic matter, using small fish as its main food resource. We conclude that the activities of fish farming influence diet and biological attributes of the species G. knerii, evidenced mainly by higher feeding activity, numerical abundance and biomass in the area of the cages.