Production and economic potentials of cattle in pasture-based systems of the western Amazon region of Brazil.

Our objectives were to evaluate strategies to improve productivity and economic returns from beef and dual-purpose cattle systems based on data collected on one dual-purpose (Bos taurus x Bos indicus) and two beef (Nellore) cattle farms in the western Amazon region of Brazil. Forage chemical composition and digestion rates of carbohydrate fractions of grazed Brachiaria decumbens and Brachiaria brizantha cv. Marandu grasses and Pueraria phaseoloides (tropical kudzu) legume were measured monthly during a 9-mo period from the end of one dry season to the end of the subsequent rainy season. Measurements of milk and growth responses to grazing these forages were used to predict animal productivity responses to dietary nutrient availability throughout an annual cycle. The ME available for gain in our simulations was always more limiting than metabolizable protein. The predicted ME available for gain was 0.50 kg/d for steers grazing B. brizantha and 0.40 kg/d for finishing steers grazing B. decumbens. Grasses contained more NDF and neutral detergent insoluble protein and less ME (P < 0.05) in the rainiest months than in the less rainy season, which resulted in 20% less predicted weight gain by growing steers (P < 0.05). Supplementation with sorghum grain was required to increase milk production and growth by 25 or 50% per animal, respectively, but this strategy was less profitable than current forage-only diets. Greater productivity of land and labor from higher stocking indicated greater net margins for beef production, but not for milk. This study suggested that more intensive beef production by judicious fertilization of grass-legume pastures and greater stocking density is the preferable strategy for owners of these cattle systems to improve economic returns under current conditions. It also might help decrease the motivation for additional forest clearing.

Changes in glycogen and trehalose content of Streptomyces brasiliensis hyphae during growth in liquid cultures under sporulating and non-sporulating conditions.

Streptomyces brasiliensis ATCC 23727 showed extensive sporulation when cultured in a liquid medium containing galactose and glutamic acid as carbon and nitrogen sources. Under such conditions, glycogen and trehalose are accumulated in the hyphae coinciding with spore formation. The results reported here suggest that glycogen accumulated in sporogenic hyphae is converted into trehalose during the final period of spore maturation. Glycogen is also accumulated in the hyphae when S. brasiliensis is cultured under conditions which did not support sporulation. Under such conditions, however, glycogen degradation is not accompanied by accumulation of trehalose. This suggest that the conversion of glycogen into trehalose might be a sporulation-specific event in streptomycetes.

Mycelial differentiation and spore formation by Streptomyces brasiliensis in submerged culture.

Streptomyces brasiliensis ATCC 23727 showed extensive sporulation when cultured in a liquid medium containing galactose and glutamic acid as carbon and nitrogen sources. Sporogenic hyphae formed under these conditions were morphologically similar and developmentally equivalent to aerial hyphae and metamorphosed into chains of spores by following a sequence of ultrastructural changes similar to that observed during growth on solid media. In addition, our electron microscopy study revealed two previously unrecognized aspects of hyphal development in streptomycetes: the formation of sporogenic hyphae was always preceded by changes in the structure of the nucleoid, and the sheath that characteristically covered these hyphae was not deposited coincidently with wall formation in the apical growing portion of the hypha.

[Current participation of the nurse in the activities covered in the "expanded role of nursing"]. / Participación actual de la enfermera en las actividades comprendidas en el "papel ampliado de enfermería".

The article reports on a survey conducted in Colombia to evaluate the part played by the nurse in the functions covered by what has come to be called "the expanded role of nursing." According to the survey, there are 2,213 practicing nurses, who are clustered in the principal cities of the country. Those who participated in the study are young nurses holding staff positions in such institutions as university and social security hospitals. Their training is mostly at the university level, and they have had five years or less of experience. The article notes that, to perform the duties of the expanded role, the nurse must participate in accordance with her training, interest and motivation. The participation may be conditioned by factors in the nurse herself (prior knowledge, former training, previous participation, and responsibility) and by factors in the working environment (the person who instructed her on her role, the post she holds, her length of service/length of her work day, permission received from the institution to exercise her function, and the medical and nursing agreement). Parodoxically, the nurse is being made a participant in new functions at hospitals where there are medical resources and not in regions and places where those resources are scarce or nonexistent. The expanded role of nursing opens to the nurse a range of activities that enable her to provide quality care to the patient and to his or her family and community, to extend the coverage of health services, and offer treatment effectively.