277 research outputs found
Herbaceous production in South India-limiting factors and implications for large herbivores
This study's goal was to better understand the growth pattern and limitations of the herbaceous production that supports South India's rich large herbivore grazer assemblage. We conducted a fully factorial nitrogen and water (three levels each) treatment field experiment in the herbivore rich South Indian Western Ghats region to determine the seasonal pattern and the extent to which nitrogen and water availability limit herbaceous production. Graminoid production was found to be nitrogen limited. Despite low rainfall, additional water did not significantly increase overall biomass production nor extend growth in the dry season. Accumulated standing biomass was highest in the late wet season (November) and lowest in the dry season (May). Leaf nitrogen was highest in the early wet season (June) and lowest in the late dry season (March). Grazing had a positive effect on grass production by extending the growing season. Biomass production and graminoid leaf nitrogen concentration levels in the study area were similar to other tropical areas in the world. Also similar to other tropical large herbivore areas, the dry season poses an annual challenge for large herbivores in the study area -particularly the smaller bodied species-to satisfy their nutrient requirements
Contrasting timing of parturition of chital Axis axis and gaur Bos gaurus in tropical South India - the role of body mass and seasonal forage quality
Seasonal variation in forage availability and quality is understood to affect the annual timing of parturition in large herbivores. In India-where seasonal monsoonal rains define variation in forage availability and quality-chital Axis axis exhibit stronger seasonality in parturition than the larger gaur Bos gaurus. We hypothesized that this difference can be explained by forage requirements determined by body mass. We developed a model to simulate changes in leaf biomass and nitrogen content based on plant available moisture and nutrients, and calibrated our model with field data. Our results show that the minimum forage nitrogen content required by lactating gaur was available throughout the year, but that required by lactating chital was available for less than 40% of the year, i.e. during the early wet season, which coincides with the annual peak period of chital births. The three to four month spread of chital births, which begins in the dry season, implies that the period of highest quality is also important for females to replenish maternal reserves for future reproduction and help maximize the growth rate of neonates. This spread also indicates low synchrony of chital births and suggests that predator swamping was less important in influencing their timing of parturition. As monsoonal rain exhibits annual temporal variation, we analyzed our model under different rainfall patterns while keeping the total annual rainfall constant. We found that the difference between the durations of how long forage quality is available to satisfy the minimum requirements of lactating gaur and lactating chital is similar for all simulated patterns. This insensitivity to variable rainfall patterns lends support to our hypothesis that forage requirements determined by body mass is one plausible explanation for the variation in parturition strategies among large herbivores species
In-vitro germination of two endemic species from Berlengas Archipelago, Pulicaria microcephala and Armeria berlengensis
info:eu-repo/semantics/publishedVersio
Marital status and health: Descriptive and explanatory studies
DUring the last 30 years social factors have become increasingly important in the
evolution of concepts of disease etiology. In the beginning of this century the
germ theory and its monocausal orientation, attributing single diseases to single
causes (i.e. infectious agents), dominated medical thinking. However, the
germ theory failed to explain why only some of those persons exposed to
pathogens actually contracted the disease. In addition, the germ theory was less
appropriate for the explanation of degenerative causes of death such as
cardiovascular diseases and malignant neoplasms, which have replaced Infectious
diseases as the main causes of death in this century. The monocausal concept
of disease etiology was followed by a multicausal orientation, which emphasized
the presence of several interacting causal factors. Multicausal research Initially
focused on biological risk factors, such as high serum cholesterol, high blood
pressure and cigarette smoking in the development of coronary heart disease.
However, this approach also proved to be only partly successful in pinpointing
the causes of disease. For instance, only a relatively small proportion of all
persons with high serum cholesterol and high blood pressure who smoke cigarettes,
develop coronary heart disease and many persons who lack most of these
risk factors do develop coronary heart disease. Thus, other factors must be
involved in the etiological process. Groups differentiated by social factors have
long been found to exhibit characteristic mortality and morbidity patterns. These
health differences between social groups (e.g. dif
Independent variation of avian sensitivity to climate change and trait-based adaptive capacity along a tropical elevational gradient
Independent variation of avian sensitivity to climate change and trait-based adaptive capacity along a tropical elevational gradient
Characteristics of beef from intensively fed western Baggara bulls and heifers: quality attributes and chemical composition
Fourteen samples of L. dorsi muscles were taken from western Baggara cattle, one sample from each of seven bulls and seven heifers randomly selected for slaughter at the end of an experimental feedlot feeding which lasted for 16 weeks at Kuku Research Station, Khartoum North, Sudan, to study sex effects on meat chemical composition and quality attributes. Moisture content of beef was higher in bulls meat than in heifers meat. Protein and ash content were significantly (P<0.001) higher in bulls meat, whereas fat content was significantly (P<0.001) higher in heifers meat than in bulls meat. Cooking loss of bulls meat was significantly (P<0.001) lower and water-holding capacity was also significantly (P<0.01) lower in the bulls meat than in heifers meat. Bull’s meat colour had low lightness (L) and high redness (a) and yellowness (b), as determined by Hunter Lab. Tristimulus colorimeter, as compared with heifers meat. Sensory panelist scores were higher for colour darkness and flavour intensity and lower for tenderness, juiciness and overall acceptability of bulls meat as compared with heifers meat
Ethnic differences in mortality, end-stage complications, and quality of care among diabetic patients: a review
OBJECTIVE: To determine the influence of ethnic differences in diabetes
care on inequalities in mortality and prevalence of end-stage
complications among diabetic patients. The following questions were
examined: 1) Are there ethnic differences among diabetic patients in
mortality and end-stage complications and 2) are there ethnic differences
among diabetic patients in quality of care? RESEARCH DESIGN AND METHODS: A
review of the literature on ethnic differences in the prevalence of
complications and mortality among diabetic patients and in the quality of
diabetes care was performed by systematically searching articles on
Medline published from 1987 through October 2004. RESULTS: A total of 51
studies were included, mainly conducted in the U.S. and the U.K. In
general, after adjusting for confounders, diabetic patients from ethnic
minorities had higher mortality rates and higher risk of diabetes
complications. After additional adjustment for risk factors such as
smoking, socioeconomic status, income, years of education, and BMI, in
most instances ethnic differences disappear. Nevertheless, blacks and
Hispanics in the U.S. and Asians in the U.K. have an increased risk of
end-stage renal disease, and blacks and Hispanics in the U.S. have an
increased risk of retinopathy. Intermediate outcomes of care were worse in
blacks, and they were inclined to be worse in Hispanics. Likewise, ethnic
differences in quality of care in the U.S. exist: process of care was
worse in blacks. CONCLUSIONS: Given the fact that there are ethnic
differences in diabetes care and that ethnic differences in some diabetes
complications persist after adjustment for risk factors other than
diabetes care, it seems the case that ethnic differences in diabetes care
contribute to the more adverse disease outcomes of diabetic patients from
some ethnic minority groups. Although no generalizations can be made for
all ethnic groups in all regions for all kinds of complications, the
results do implicate the importance of quality of care in striving for
equal health outcomes among ethnic minoriti
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