RESUMEN
The aim of this study was to investigate the influence of agricultural intensification on soil microbial diversity, chemical and physical parameters, and the decrease of the incidence of sudden death syndrome (Fusarium crassistipitatum) and charcoal rot (Macrophomina phaseolina) in soybean. Soils under different management systems were evaluated during 2 crop cycles: soybean monoculture for 24 and 11 years, soybean-maize rotation for 15 and 4 years, 1 year of soybean, and native vegetation. The incidence of both soil-borne diseases was higher under monoculture than under rotation. Increased populations of potential biocontrol agents (Trichoderma spp., Gliocladium spp., fluorescent pseudomonads) were associated with rotation treatments, especially in 2010-2011. The comparison of agricultural vs. native vegetation soil and the average of agricultural cycles showed that microbial biomass carbon and glomalin-related soil protein were higher in the rotation system than in monoculture (50% and 77%, respectively). Furthermore, from the community-level functional diversity (Biolog Eco plates), McIntosh index showed lower functional diversity in monoculture than in rotation and native vegetation plots. Agricultural intensification reduced microbial biomass carbon, glomalin-related soil protein, organic matter, total nitrogen, aggregate stability, and yield, and increased bulk density. Soil quality degradation was associated with the establishment of soil-borne pathogens and increased soybean plant susceptibility to disease.
Asunto(s)
Agricultura , Ascomicetos/fisiología , Fusarium/fisiología , Glycine max/fisiología , Microbiología del Suelo , Biodiversidad , Biomasa , Carbono/análisis , Nitrógeno/análisis , Suelo/química , Glycine max/microbiología , Zea mays/fisiologíaRESUMEN
Increasing the knowledge of the semen characteristics in the alpaca will contribute to understanding one of the many factors that affect the poor fertility rate in this species. Ten adult male alpacas, 2.6-10 years of age, average weight 64.7 +/- 4.7 kg were used. The animals were distributed randomly into two groups of five each and submitted alternatively to two semen collections, using an artificial vagina and sexually receptive females. For the first semen collection the animals had a sexual rest period of about 90 and 45 days before the second. Duration of semen collection, color and volume of ejaculate were recorded, and sperm concentration and morphology (light microscopy) were evaluated. Descriptive statistical analyses were used for each variable, considering all samples obtained (n= 19). An analysis of variance for animal groups and opportunity of collection were used for quantitative variables. Most frequent color was opalescent white (84.2%). There were no statistical differences among male groups or between semen collections. The average values and standard deviations for the quantitative variables were: 12.3 +/- 7.2 min for semen collection time, 1.8 +/- 0.8 ml for ejaculate volume, (17.6 +/- 26.1) x 10(6) sperm/ml for sperm concentration and 34.0 +/- 52.2 x 10(6) for total number of sperm per ejaculate. The percentage of normal spermatozoa was 51.0 +/- 12.4%. From the total abnormalities, that of mid piece segment (14.4%) was the most frequent. These results indicate that male alpaca have poor semen quality, when compared with other domestic species. Nevertheless, for the evaluation of male alpaca as breeders it would be necessary to create a protocol for the selection of them, where phenotypic, behavioral and seminogram aspects are considered. The values reported herein define the characteristics of the alpaca semen that could be considered as the initial base of the seminal analysis to select male alpacas before mating.
Asunto(s)
Cruzamiento , Camélidos del Nuevo Mundo , Semen/fisiología , Animales , Color , Femenino , Masculino , Recuento de Espermatozoides , Cabeza del Espermatozoide , Cola del Espermatozoide , Espermatozoides/anomalíasRESUMEN
Besides utilitarianism, there are different ways to understand Medicine and its role. The opinion of the author is that the pursuit of mankind welfare is not the role of physicians and that their responsibility is not referred to the world. On the contrary, their bumble mission is to cure or mitigate pain through therapeutic actions. Any other way of proceeding means that the medical action is becoming orchestrated, destroying the fundamental value of patient physician relationship. This article intends to demonstrate the insufficiency of the Aristotelian idea of technique applied to medicine and that, on the other hand, the modern ideal of a principle free science does not account for the complexity of medical practice, mainly in the field of Psychiatry. Finally the author wonders if the moral convictions of physicians may play a role in the treatment of specific diseases caused by morally inadequate behaviors.