58 research outputs found

    Seasonal diet changes in elephant and impala in mopane woodland

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    Elephant and impala as intermediate feeders, having a mixed diet of grass and browse, respond to seasonal fluctuations of forage quality by changing their diet composition. We tested the hypotheses that (1) the decrease in forage quality is accompanied by a change in diet from more monocots in the wet season to more dicots in the dry season and that that change is more pronounced and faster in impala than in elephant; (2) mopane (Colophospermum mopane), the most abundant dicot species, is the most important species in the elephant diet in mopane woodland, whereas impala feed relatively less on mopane due to the high condensed tannin concentration; and (3) impala on nutrient-rich soils have a diet consisting of more grass and change later to diet of more browse than impala on nutrient-poor soils. The phosphorus content and in vitro digestibility of monocots decreased and the NDF content increased significantly towards the end of the wet season, whereas in dicots no significant trend could be detected. We argue that this decreasing monocot quality caused elephant and impala to consume more dicots in the dry season. Elephant changed their diet gradually over a 16-week period from 70% to 25% monocots, whereas impala changed diets rapidly (2-4 weeks) from 95% to 70% monocots. For both elephants and impala, there was a positive correlation between percentage of monocots and dicots in the diet and the in vitro digestibility of these forage items. Mopane was the most important dicot species in the elephant diet and its contribution to the diet increased significantly in the dry season, whereas impala selected other dicot species. On nutrient-rich gabbroic soils, impala ate significantly more monocots than impala from nutrient-poor granitic soils, which was related to the higher in vitro digestibility of the monocots on gabbroic soil. Digestibility of food items appears to be an important determinant of diet change from the wet to the dry season in impala and elephants

    Stock assessment of freshwater crayfish (Astacus leptodactylus) in Aras reservoir

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    360 funnel traps were prepared as 30 in one row. They were bitted and located in different depths in sampling sites. Two rows each composed of 30 traps were located by stone, linking rope and boat with 50 m distance in sampling stations. The results showed that the average of total length of caught crayfish was 106.26±12.89 mm and their mean weight was 38.79 ± 15.54 gr. The largest crayfish had 171 mm length and 216 g weight. Also mean of total CPUE was 9.72±4.49 individuals in the study period. The evaluation by Schnabel approach indicated that fluctuation range of freshwater crayfish biomass with more than 120mm length was 131-313 with an average of 212.59 ±30.23 kilograms per ha. In this study freshwater crayfish biomass with more than 120mm length was 247 × 10^3 kilograms. The Maximum Sustainable Yield (MSY) was estimated 83 × 10^3 kilograms. In this study ّFecundity and biometry of crayfish (Astacus leptodactylus) was investigated during 2012-2013. The results showed that the average of total length of caught crayfish was 106.26±12.89 mm and their mean weight was 38.79 ± 15.54 gr. The largest crayfish had 171 mm length and 216 g weight. Mean number of ovarian and pleopodal eggs were estimated at 286 ± 82 and 246.31 ± 80.41 eggs (with 95% confidence limits), respectively. In this research, male to female ratio was obtained 1.21:1. The time of male moulting at 16°C was started from April and was ended in the late May, when the water temperature reached to 18° C. The second moulting of males and the first moulting of females was performed simultaneously in 18°C water temperature at September. Reproduction of freshwater crayfish was started from November and continued to May of the next year. Harvesting period was from May to late November

    A qualitative evaluation of volunteers' experiences in a phase I/II HIV vaccine trial in Tanzania

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    Evaluating experiences of volunteers in an HIV vaccine trial will be useful for the conduct of future trials. The purpose of this study among volunteers who participated in a phase I/II HIV vaccine trial in Dar es Salaam, Tanzania was to assess what characterized their experiences during the trial. We conducted four focus group discussions with 35 out of the 60 individuals (women and men) after the five scheduled vaccinations. An interpretive description approach was applied to data analysis. As a result of the trial interventions, both men and women gained confidence in their own abilities to have safer, less risky sexual behaviour. The participants experienced the trial as a way of accessing free [insured] medical services. Most of the men said they had gone from self-medication to professional medical consultation. Despite these benefits, the participants faced various challenges during the trial. Such challenges included mistrust of the trial shown by health care providers who were not connected to the trial and discouragement from friends, colleagues and family members who questioned the safety of the trial. However, they managed to cope with these doubts by using both personal and trial related interventions. We found that during the phase I/II HIV vaccine trial, participants had both the opportunities and the ability to cope with the doubts from the surrounding community. Follow up visits enhanced the opportunities and individuals' abilities to cope with the doubts during the trial. Understanding this discourse may be useful for the trial implementers when designing future trials.\ud \ud \ud \u

    Balancing collective responsibility, individual opportunities and risks: a qualitative study on how police officers reason around volunteering in an HIV vaccine trial in Dar es Salaam, Tanzania

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    Results from HIV vaccine trials on potential volunteers will contribute to global efforts to develop an HIV vaccine. The purpose of this study among police officers in Dar es Salaam, Tanzania, was to explore the underlying reasons that induce people to enrol in an HIV vaccine trial.\ud We conducted discussions with eight focus groups, containing a total of 66 police officers. The information collected was analyzed using interpretive description. The results showed that participants were motivated to participate in the trial by altruism, and that the participants experienced some concerns about their participation. They stated that altruism in the fight against HIV infection was the main reason for enrolling in the trial. However, young participants were seriously concerned about a possible loss of close relationships if they enrolled in the HIV vaccine trial. Both men and women feared the effect of the trial on their reproductive biology, and they feared interference with pregnancy norms. They were unsure about risks such as the risks of acquiring HIV infection and of suffering physical harm, and they were unsure of the intentions of the researchers conducting the trial. Further, enrolling in the trial required medical examination, and this led some participants to fear that unknown diseases would be revealed. Other participants, however, saw an opportunity to obtain free health services.\ud We have shown that specific fears are important concerns when recruiting volunteers to an HIV vaccine trial. More knowledge is needed to determine participants' views and to ensure that they understand the conduct of the trial and the reasons it is being carried out

    Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation

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    In savannas, the tree–grass balance is governed by water, nutrients, fire and herbivory, and their interactions. We studied the hypothesis that herbivores indirectly affect vegetation structure by changing the availability of soil nutrients, which, in turn, alters the competition between trees and grasses. Nine abandoned livestock holding-pen areas (kraals), enriched by dung and urine, were contrasted with nearby control sites in a semi-arid savanna. About 40 years after abandonment, kraal sites still showed high soil concentrations of inorganic N, extractable P, K, Ca and Mg compared to controls. Kraals also had a high plant production potential and offered high quality forage. The intense grazing and high herbivore dung and urine deposition rates in kraals fit the accelerated nutrient cycling model described for fertile systems elsewhere. Data of a concurrent experiment also showed that bush-cleared patches resulted in an increase in impala dung deposition, probably because impala preferred open sites to avoid predation. Kraal sites had very low tree densities compared to control sites, thus the high impala dung deposition rates here may be in part driven by the open structure of kraal sites, which may explain the persistence of nutrients in kraals. Experiments indicated that tree seedlings were increasingly constrained when competing with grasses under fertile conditions, which might explain the low tree recruitment observed in kraals. In conclusion, large herbivores may indirectly keep existing nutrient hotspots such as abandoned kraals structurally open by maintaining a high local soil fertility, which, in turn, constrains woody recruitment in a negative feedback loop. The maintenance of nutrient hotspots such as abandoned kraals by herbivores contributes to the structural heterogeneity of nutrient-poor savanna vegetation

    "I am nothing": experiences of loss among women suffering from severe birth injuries in Tanzania

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    \ud Despite the increased attention on maternal mortality during recent decades, which has resulted in maternal health being defined as a Millennium Development Goal (MDG), the disability and suffering from obstetric fistula remains a neglected issue in global health. Continuous leaking of urine and the physical, emotional and social suffering associated with it, has a profound impact on women's quality of life. This study seeks to explore the physical, cultural and psychological dimensions of living with obstetric fistula, and demonstrate how these experiences shape the identities of women affected by the condition. A cross-sectional study with qualitative and quantitative components was used to explore the experiences of Tanzanian women living with obstetric fistula and those of their husbands. The study was conducted at the Comprehensive Community Based Rehabilitation Tanzania hospital in Dar es Salaam, Bugando Medical Centre in Mwanza, and Mpwapwa district, in Dodoma region. Conveniently selected samples of 16 women were interviewed, and 151 additional women responded to a questionnaire. In addition, 12 women affected by obstetric fistula and six husbands of these affected women participated in a focus group discussions. Data were analysed using content data analysis framework and statistical package for the social sciences (SPSS) version 15 for Microsoft windows. The study revealed a deep sense of loss. Loss of body control, loss of the social roles as women and wives, loss of integration in social life, and loss of dignity and self-worth were located at the core of these experiences. The women living with obstetric fistula experience a deep sense of loss that had negative impact on their identity and quality of life. Acknowledging affected women's real-life experiences is important in order to understand the occurrence and management of obstetric fistula, as well as prospects after treatment. This knowledge will help to improve women's sense of self-worth and maintain their identity as women, wives, friends and community members. Educational programmes to empower women socially and economically and counselling of families of women living with obstetric fistula may help these women receive medical and social support that is necessary.\u

    Cysteinyl leukotrienes: multi-functional mediators in allergic rhinitis

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    Cysteinyl leukotrienes (CysLTs) are a family of inflammatory lipid mediators synthesized from arachidonic acid by a variety of cells, including mast cells, eosinophils, basophils, and macrophages. This article reviews the data for the role of CysLTs as multi-functional mediators in allergic rhinitis (AR). We review the evidence that: (1) CysLTs are released from inflammatory cells that participate in AR, (2) receptors for CysLTs are located in nasal tissue, (3) CysLTs are increased in patients with AR and are released following allergen exposure, (4) administration of CysLTs reproduces the symptoms of AR, (5) CysLTs play roles in the maturation, as well as tissue recruitment, of inflammatory cells, and (6) a complex inter-regulation between CysLTs and a variety of other inflammatory mediators exists.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75432/1/j.1365-2222.2006.02498.x.pd

    Effect of dietary starch source on milk production and composition of lactating Holstein cows

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    The objective of this study was to evaluate the effects of four sources of starch on milk production and composition, nutrient digestion and blood metabolites of lactating Holstein cows. Four multiparous Holstein cows (708 ± 70 kg of body weight; 83 ± 9 days in milk) were used in a 4 × 4 Latin square design with 21-d periods. The concentrate portion of the diet contained wheat, barley, maize or potato as the primary source of starch. Intake of dry matter (DM) ranged from 18.7 kg/d to 19 kg/d, and was similar among treatments. Milk production was higher in cows fed the wheat-based diet compared with other diets while the milk fat concentration of the cows fed the maize-based diet was the highest. Milk protein concentration was unaffected by the source of dietary starch. Cows fed the potato-based diet had a lower milk protein, lactose and solid-non-fat yield. Milk yield/kg of DM intake and net energy for lactation (NEL)/NEL intake were higher in cows fed wheat-, barley- or maize-based diets compared with those fed the potato-based diet. Feed nitrogen efficiency was higher in cows fed the maize-based diet compared with the other experimental diets. Total tract apparent digestibility of organic matter, crude protein and ether extract were higher in cows fed the wheat- or maize-based diets compared with those fed barley- or potato-based diets; however, total tract apparent digestibility of neutral detergent fibre and acid detergent fibre were higher in cows fed the wheatbased diet compared with those fed the potato-based diet. These results showed that improved production performance in cows fed the wheat-based diet appeared to be because of greater nutrient digestibility and greater nutrient utilization efficiency. Furthermore, potato starch is not superior to grain starch as a readily available energy source for lactating dairy cows.Keywords: Nutrient digestibility, nutrient efficiency, plasma metabolites, wheat, barley, potato, maiz
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