Masters Dissertations

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Levels and distribution of heavy metals in soil maize and rice within the vicinity Of Buzwagi gold mine Kahama Tanzania
(University of Dar es salaam, 2019) Petro, Phares Maximilian Doyi
This dissertation reports on the levels and spatial distribution of Cd, Fe, Co, Cu, Pb, Zn and Hg in maize, rice and soil in the vicinity of Buzwagi gold mine, Kahama, Tanzania. The concentrations of heavy metals were compared with FAO/WHO and/or TBS standards. The methods involved random and systematic sampling, extraction by using wet acid digestion and determination of the levels of heavy metals by AAS, with the exception of mercury which was analyzed using a Direct Mercury Analyzer (DMA). Analysis of variance ( ANOVA) and t-test using Graphpad Instant Demo software were employed for data analysis. The mean levels of Cd, Fe, Co, Cu, Pb, Zn and Hg at Mwime village in mg/kg were 9.34, 122969, 22.2, 79.6, 20.80, 38.9 and 0.02 in soil BD L 57, 15.1, 14.7, BDL, 21.1 and 0.16 in maize and BDL, 96.82, BDL, 5.53, BDL, 16.37 and 0.295 in rice, respectively. The mean levels of Cd, Fe, Co, Cu, Pb, Zn and Hg at Chapulwa in mg/kg were 13.6, 134913, 27.1, 54.1, 23.2, 22.01 and 0.036 in Soil, BDL, 34.77, BDL, 1.7, BDL, 17.4 and 0.03 in maize and BDL,26.50, BDL,4.70, BDL,16.03 and 0.37, in rice respectively. In addition the mean levels of Cd, Fe, Co, Cu, Pb, Zn, and Hg at Mwendakulima in mg/kg were BDL, 1782600, 26.3, 72.6, 18.3, 39.1 and 0.03 in soil, BDL 64.10, BDL, BDL, 5.53, BDL, 16.3 and 0.04 in maize and bdl, 88.21, BDL, 2.46, BDL, 16.03 and 0.04 in rice respectively. The study has shown that levels of Cu, Zu, and Hg in rice at Mwime, Chapulwa and Mwendakulima villages are above FAO/ WHO (2001) limits. In addition, Fe in rice at Mwime and Mwendakulima Villages has been found to be above FAO/WHO (2001) set limits. For maize, analysis results have shown that Zn and Hg are above FAO/WHO (2001) limits. Furthermore, Fe at Mwime and Mwendakulima villages and Co at Mwime village have also been found to be above FAO/ WHO limits. Likewise, Fe in soil at Mwine, Chapulwa and Mwendakulima villages have been found to be above FAO/WHO (2001) limits, and Cd at mwime and Chapulwa villages also recorded above FAO/WHO (2001) set limits. The level of heavy metals increased with increase in distance from Buzwagi gold mine through Mwime village whereas it is decreased with increase in distance from Buzwagi gold mine through Chapulwa and Mwendakulima villages. In the determination of the transfer factors (TF), the results have shown that about 70% of Hg uptake by maize and rice are above 100% and therefore people in the vicinity are susceptible to health risks.
Investigation of somewhere dense and dense orbits on complex Hilbert space
(University of Dar es salaam, 2018) wilberth, Neema
This dissertation forms part of the study of operator theory results for somewhere dense orbits and hypercyclic operators. Somewhere dense orbits are one of the generalizations of the notion of dense orbits. In this study first we present the existence of n- tuple of operators on complex Hilbert space that has a somewhere dense that is not dense. We gave the solution to the question which was posed by Feldman 2008: “Is there n- tuple of operators on a complex Hibe space that has a somewhere dense orbit and is not dense? We do so by extending the results due to Feldman 2008 from real Hilbert space to complex Hilbert space. The second major topic that we investigate in this study is hypercyclicity. Hypercyclicity is the study of linear and continuous operators that possess dense orbits. We extended the results due Costakis et al. 2009 by showing the existence of hypercyclic (non diagonalizable) n - tuple of matrices in Jordan form to C”. In doing so we modified some lemmas from 2x2 matrices in Jordan from to 2x2 matrices in lower triangular form and to 3x3 matrices in Jordan form and some propositions and theorems from H to C. Next, let T1, T2 be continuous linear operators acting on Banach space X and (T1, T2) be a pair of operators. We answered the question raised by Feldman 2003 which states that “if (T1, T2 ) is hypercyclic pair is (T1 T1, T2 T2 ) also a hypercyclic pair? We showed that indeed that (T1, T1, T2 T2) is hypercyclic pair and it satisfies the hypercyclic criterion. Illustrative example of somewhere dense orbits and hypercyclicy operators are given to support the results.
Prevalence of Cryptosporidium a diarrhhoeal associated pathogens among under five children in korogwe district, Tanzania: a case of korogwe District, Tanga
(University of Dar es salaam, 2019) Mbwana, Joyce Richard
Cryptosporidium is the second leading cause of diarrheal illness in the children. In low – and Middle-income Countries (LMICs). Diarrheal illness is rarely diagnosed and transmission dynamics of Cryptosporidium are not well understood. Although diarrhea can be self-limiting. In children the disease can be life threatening. A cross-sectional study was conducted to determine the prevalence and characterize the Cryptosporidium species in children in order to delineate the disease transmission dynamics and patterns in Korogwe Districts, Tanzania. Stool specimens were screened for the presence of Cryptosporidium parasitic infection by Crypto Rapid test and repeated by multiplex real-time polymerase chain reaction (qPRC). A modified genotyping PCR was performed to identify different genotype associated with diarrheal. Subsequently, sub – typing and phylogenetic analyses based on gp 60 gene was done to identify sub—types and transmission pattern of Cryptosporidium in the study area. A total of 356 children with moderate to severe diarrhea were enrolled in the study in the study. The overall prevalence of Cryptosporidium was (49/136) 13.8% [95%CI== 10.5 -17.8] of whom (42/49) 85.7% were aged between (0-2) years and (7/49) 14.3% were between (3-5) years. Cryptosporidium hominis was the most predominant species (35/37) 94.6% whereas C. parvum accounted for only (2/37) 5.4%. Upon further sub-typing. C hominis revealed the highest sub-type were [EaIIg3t3.iAa24, IbA9g3. iDa17 and IfA14G. Furthermore, phylogenetic analysis of nucleotide sequence showed an evidence of human to human transmission. This study has revealed a high prevalence of Cryptosporidium infections among children especially those aged below 24 months at korogwe District Hospital with main source of transmission being contaminated water and food. In order to combat Cryptosporidium related diarrheal illness in the study area. Access to safe drinking water and sanitary education should be improved
Assessment of wind energy potential at selected locations in Zanzibar using two-parameter weibull distribution function
(University of Dar es salaam, 2019) Juma, Hamad
Linear regression was used to examine the relationship between the wind speed data collected by TMA and that of the Reanalysis I. the results of regression indicated that correlation between the in-situ wind speed data and reanalysis wind speed data from Pemba Airport (PA) and Zanzibar international airport (ZIA) metrological stations are weakly positive correlated with corresponding R of 0.434. The result of regression at ZIA provided confidence of determination of 0.186 with level of significance of p< 0.001 and the predictive model y = 3.007 + 0.520x. the result of regression at PA provided coefficient of determination of 0.080 with level of significance of p<0.001 and the predictive model y = 4.370 + 0.256x. Regression equations derived in PA and ZIA data were used to predict monthly mean wind speeds of Makunduchi and Micheweni, respectively. The results revealed that the highest wind speed at Makunduchi was 6.10m/s which was observed in June 1986 and the lowest wind speed was 3.77m/s that occurred in March, 2007. The overall monthly average value was found to be 4.88m/s. The highest wind speed at Micheweni was 6.04m/s observed in January, 1986 and the lowest wind speed was 4.85m/s and 5.54m/s which were observed in 1989, while lowest annual mean wind speeds were 4.83m/s and 5.37m/s and 5.37m/s which occurred in 2014 and 2007 respectively 13.86 and 5.23m/s. The average value of shape and scale parameters for Micheweni is respectively 26.75 and 5.56 m/s. The maximum wind power densities of Makunduchi and Micheweni at 10m AGL was 126.31 W/m2 and 136.47W/m2, while the minimum were 90.97 W/m2 and 109.22 W/m respectively. As for 80m AGL the maximum was 302.51 W/m and 326.84 W/m and the minimum was 217.87W/m2 and 261.58 W/m2, respectively. It was concluded that Michewenni is a more adequate site than Makunduchi because it has a higher wind power density
The burden of malaria and helminthes infections among primary school children in Mvomero district, Morogogo, Tanzania
(University of Dar es salaam, 2020) Kisiringyo, Christopher Mkara
In many regions of Sub-Saharan Africa, helminthes infections overlap geographically with P. falciparum, resulting an increasing burden of Pf and helminths parasitaemia. That is public health significant. A school based across-sectional study was conducted to investigate the burden and the relationship between Pf and helminthes infection in Mvomero district. Formal-ether concentration and Mac master methods were used to determine helminths egg densities, microscopy field-stained thick blood smears were used to determine asymptomatic and symptomatic malaria parasitaemia. Structured questionnaire and interviews were administered to capture KAPs items. About 374 children of 5-16 years old were recruited from five primary schools. Prevalence of asymptomatic Pf malaria was 29.9%, S. haematobium 49.7%, STHs 20.6% to assess the influence of helminths infection on the severity of malaria, 326 patients aged 5-17 years old were recruited from three health facilities. About 46.9% of children were positive for symptomatic Pf. Children with Pf-helminths co-infection were more anemic than those with Pf alone. This study also revealed inaccurate and poor knowledge about transmission and control of malaria and helminths infection among children, In general, prevalence of both asymptomatic Pf malaria as well as Pf-helminths-confection has decreased by over 40% in the study area. However, prevalence of S. haematobium and hookworm infections is alarmingly high and influence severity of malaria in the locality. This calls for community based-integrative control measures in-cooperating strategies to combat both Pf and helminths infection reservoirs in Mvomero district
Macroalge Diversity, Levels of Physicochemical Parameters and Anthropogenic Activities at selected sites along the Dar es salaam Coast.
(University of Dar es salaam, 2019) Rusekwa, Sadock Pili Boniface
Anthropogenic activities have been reported to cause a change in macroacroalgae diversity. This study aimed at assessing microalgae diversity of microalgae in six sites along Dar es salaam coast; estimating abundance (cover) of selected microalgae species, determining the levels of selected physicochemical parameters as well as documenting human a ctivities in study sites. The study was conducted between June, 2016 and august, 2017. Opportunistic randomly sampling was done within the studied areas during spring low tide. Identification of all collected seaweed samples was done on site and in the laboratory. A total of one hundred and seven (107) species of macroalgae were recorded from all sites. The division Rhodophyta contributed 48%, Chloraphyta (25%), Ochrophyta (25%) and cynophyta(25%).. Common species in all sites were Boergesenia Forbesii, Ulva Fasciata, Ulva Reticulate, Gracilaria Salicornia, Jania Capillacea Cystoceira Myrica and Padina Boryana. Oyster Bay had highest species diversity wheas lowest diversity was recorded at Oceanroad. A total of 225 species (68%) previously collected at these study sites were currently missing. The highest number of missing species was noted at Osyters Bay and the lowest number was recorded at Mjimwema. The difference in species composition and diversity between studied sites is attributed to the nature of substrate, shore topography and human activities conducted at specific site. Increase temperature and destructive human activities are attributed to decrease of macroalgae diversity and altered composition n the study sites. Mean percentage cover was high in August (29.24) ± 5.85%). The mean biomass of. U. faciata was 4.42 ± 0.65 gdw/m2 and 3.90 ± 1.25 gdw/m2 for G. salicornia. The levels of physicochemical parameters recorded at Oyster Bay were as follows: mean temperature (27 ± 0.7oC ), salinity (34.3 ± 0.8‰), Ph( 8.06 ± 0.1), Nitrate (0.091 ± 0.003 mg/l and phosphorus (0.118 ± 0.010 mg/1. In water column and were optimal for macroalgae growth requirements. Nonetheless data obtained from TMA indicates a steady increase in temperature up to 34oC in DSM Region. Human activities such as illegal fishing, trampling, swimming, boating, tourism and harvesting of microalgae for various use, were observed taking place in these study sites. The results suggest that species composition and diversity in study sites is changing and disappearance of some species is a reality.
Application of indigenous entomopathogenic fungi as potential bio-pesticides against Tuta absoluta
(University of Dar es Salaam, 2020) Renson, Camila
In Tanzania, tomato production is an important activity which has attracted farmers mainly due to its pontential in human dit and monetary gains in a relative shorter period of time. However production of tomato has been challenged with various pests in which one among them is Tuta absoluta. Chemical control of T. Absoluta has been found to b less effective and very expensive to farmers meanwhile its residue in the soil render a long-threat to plant and animal ecology. In the quest to develop an alternative control of T. Absoluta, this study was designed to identify indigenous entomopathogenic fungi that could effectively control T. Absoluta while avoiding human and environmental health impact. Thirty six (36) fungi isolates were obtained from the soil using Soboraud Dextrose Agar media. The fungal isolates were further cultured on starch agar media, Tween 20(10%) agar media and casein hydrolysis media to observe their ability to secrete amylase, lipase and proteases respectively. Eight fungi isolates were able to secrete the enzyme thus, were analyzed for their ability to inhibit T. Absoluta larvae growth under laboratory bioassays at a concentration of 1x106, 1x107 and 1x108 spores/mL at an interval of every 24 hours. Four out of eight fungi species caused mortality of pest larvae after 4 days post inoculation and then were identified by using molecular characterization methods. The isolates were identified to Aspergillus terreus, Penicillium steckii, Purpureocillium lilacinum and Purpureocillium lilacinum with mortality rate of 80%, 90%, and 80% respectively. Thus, these fungi possess features as potential biopestcides for biological control of T. absoluta and other pests especially for solaneceous plants.
The role of school boards in managing public secondary schools in Tanzania: A Study of Kinondoni District
(University of Dar es Salaam, 2020) Kihunrwa, Martin
This study examined the role of school boards in managing public secondary schools in Kinondoni District. Specifically, the study examined how the role that school boards play helped to manage public secondary schools in the district. It explored the challenges facing school boards in managing public secondary schools in the district. The data was obtained in five secondary schools (Mabwe, Boko, Kondo, Mbweni Teta and Bunju 'A') in Kinondoni District. A total of 39 respondents were involved in this study. The respondents were 2 regional education officers, 2 district education officers, 5 heads of schools, 3 ward education coordinators and 27 members from school boards. The study is both qualitative and quantitative. The data was analyzed using contingency theory. The data was also analyzed using SPSS and presented as frequencies and percentages. Some 75% of the respondents mentioned that school boards dealt with disciplinary issues relating to students and staff. Some 88% of the respondents Ea noted that school boards lacked the skills and knowledge necessary to managing schools. Furthermore, 91% of the respondents said that one of the measures taken to alleviate the challenges facing school boards in managing public secondary schools in Kinondoni was training. Training is necessary because the duties of school boards are complex.
Pathogenicity of fusarium oxysporum and effectiveness of chemical fungicides in combating cashew wilt disease in southern Tanzania
(University of Dar es Salaam, 2020) Valerian, William
Cashew (Anacardium occidentale L.) is an economic important cash crop in Tanzania. Despite its importance, cashew is threatened by biotic factors particular diseases. Currently, a new and serious destructive disease called Cashew Fusarium Wilt (CFWD) caused by Fusarium oxysporum has emerged. Limited information exists on appropriate management strategies against the disease, characterization and its pathogenicity. This study investigated chemical management options for the disease, characterization and pathogenicity of the causative pathogen in Lindi and Mtwara regions. The causative agent was isolated and morphologically characterized while pathogenicity tests included isolation from infected plant, inoculation to healthy plant followed by re-isolation from inoculated health seedling with similar symptoms. Three chemical fungicides: azoxystrobin, carbendazim and thiophanate methyl at different concentrations were tested under in vitro, in vivo and in situ conditions. Field and pathogenicity characterizations revealed the yellowish and brownish of leaves are CFWD symptoms caused by Fusarium oxysporum; characterized by whitish mycelia growth, chlamydospores, macroconidia and microconidia. The tested chemical fungicides significantly inhibited the mycelium growth, reduced disease severity and enhanced recovery of cashew compared to untreat under in vitro, in vivo and in situ conditions respectively (P < 0.001). Carbendazim and thiophanate methyl at all concentrations and azoxystrobin at 300 ppm, inhibited fungal growth by 100 percent. In in-vivo, carbendazim (0.2 g/L), thiophanate methyl (0.6 g/L) and azoxystrobin (0.6 g/L) effectively reduced disease severity from 11.8 to 0.9%, 11.5 to 1.3% and 11.3 to 0.2% respectively. In situ application of carbendazim at 10 g/L, azoxystrobin at 15 g/L and thiophanate methyl at 15 g/L enhanced cashew recovery from Fusarium wilt disease by 49.4, 65.2 and 21.6 percent's respectively. The study recommends the use of Carbendazim, Azoxystrobin and Thiophanate methyl in the management of CFWD in Tanzania. Further studies to establish the effect of the applied chemicals to other biota for betterment and continued applications to combat the disease are required.
Crop economies during early colonial encounters on the northeast coast of Tanzania. Continuity and change.
(University of Dar es salaam, 2019) Mark, Sinyati Robinson
This study investigated the indigenous crop economies of the people inhabiting Mtang’ata Bay and Pangani Bay on the northeast coast of Tanzania from the 16th to the 19th centuries within the context of the early colonial encounters. It has been argued that the early colonial encounters posed enormous stress to the indigenous crop economies and dietary patterns on the northeast coast of Tanzania. This argument is largely based on historical accounts, and not on archaeological evidence. Therefore, this study investigated whether or not the indigenous economies were affected by the early colonial encounters, using archaeobotanical evidence . specifically, this study sought to (i) identify the crop species that were produced/ consumed in Mtang’ata Bay and Pangani Bay from the pre- colonial period to the early colonial period; (ii) examine whether the crop species continued or changed in the context of the early colonial encounters; iii) to assess the factors for such dynamics. Methodologically, archaeogical excavation for soil samples collection, a manual bucket floatation method and macro botanical laboratory analysis were undertaken to obtain archaeobotanical results. The results of this study show some continuity and change in the crops from the pre-colonial period to the early colonial period. The indigenous communities might have continued growing the traditional crops because of their important role in their diet and their ability to tolerate harsh climatic conditions like drought. Also continuous growing of the crops by them probably signifies their early resistance to the colonial crop economy. In contrast, the adoption of the new crops such as finger millet, maize and colve was perhaps for the purpose of creating more diversified crop economies by avoiding overdependence on any crop. On the basis of the archaeobotanical evidence obtained, this study concludes that there was both continuity and change in the crop economies in the context of the early colonial encounters in Mtang’ata Bay and Pangani Bay.
Structural interpretation of 2d seismic in the northern part of East Pande block, southern coast of Tanzania
(University of Dar es Salaam, 2019) Shekarata, Chonge Rashid
Seismic reflection data (profiles) were employed to characterized geological structures in the northern East Pande Block for the aim of assessing the hydrocarbon potential of the area, which lies in the southeast offshore coast of Tanzania. Structures were evaluated using 8 seismic profiles in 2D; 6 cross-line trending EW and 2 in-lines trending NS directions plus well data that included well tops, well header and well logs all of which were imported into the interactive workstation with the use of Petrel and Technology Software. Twelve – third order sequence boundaries (horizons) and two kinds of faults with a strike direction of NNW-SSE were successfully traced and picked. Faults identified are of different age resulting from two rifting events and more than one deformation episode that occurred in the area. Identified horizons were traced to produce time structure map in which later were converted to depth structural map using Time –depth relation curve. The lithology identification helped to delineate two reservoirs in the area at depth range of 3399.4m- 3835 m and 4480 m-4591 m for Top Tikiti North deepChannel-base Tikiti North deep Channel and Top Tende-based Tende respectively. Also, the existence of reservoirs were marked by presence of perfect contour closures on surface maps produced. Through all interpretation, the faults associating to reservoir were marked as possible hydrocarbon entrapment are the structural high that corresponds to normal faults.
Time series model for predicting rainfall and temperature in Dar es salaam Tanzania
(University of Dar es salaam, 2020) Andrew, Panga Paul
THS EAF QC981.T34A537 Time series models have been used as one of methods of generating the framework of future climate change (Rainfall and Temperature). The aim of this study is to stimulate and model the climate variables such as monthly rainfall and temperature. A time series of 53 years rainfall data and 31 years temperature data of Dar es Salaam region in Eastern Tanzania have been used in this study. The data were obtained from Tanzania Meteorological Agency (TMA) and the analysis relied on seasonal ARIMA models. Box and Jenkins approach was employed in developing the models. Based on diagnostic tests, stability and reliability SARIMA (2,1,1)(1,1,1)12, SARIMA (1,1,2)(1,1,1)12 and SARIMA (2,0,2)(1,1,1)12 were found to be the appropriate models for monthly rainfall, minimum temperature and maximum temperature in Dar es salaam Tanzania, respectively. After model evaluation and validation, the forecasting was made for the upcoming ten (10) years, for rainfall from 2015to 2024, and for maximum and minimum from 2016 to 2025. In view of the forecasting there is slight decrease in the amount of projected rainfall than in recent years. Also by considering temperature, forecasting result reveals an increase in maximum and minimum temperature. The increase in temperature together with decrease in rainfall suggests that climate change could continue to have negative impacts on different economic sectors including tourism in Dar es Salaam community and this call for increased adaptive capacity to the community. Higher temperatures have effects on droughts changing rainfall patterns and availability of surface water whose consequences range from less food supply to general fewer water supplies in Dar es Salaam.
An investigation on the influence of adolescent's sexual risk behavior on learning in kinondoni municipal secondary schools
(University of Dar es Salaam, 2020) Ngowi, John William
The study investigated the adolescent's sexual risk behaviours effects on learning in Kinondoni municipal secondary schools Dar es Salaam Region. The research was guided by three objectives, which were to identify factors that contribute to adolescents sexual risk behaviours, to examine the influence of adolescents sexual risk behaviour on the learning process and to determine the best practices that parents, communities and the government can adopt to reduce adolescent's sexual risk behaviours for better learning. Lyons-Ruth and Jacobvitz (1999) served the conceptual framework adopted and modified to suit the purpose of the study. The review of literature covered theoretical stances, and theories on adolescent's sexual risk behaviours, factors that contribute to adolescents' sexual risk behaviours, the influence of adolescents' sexual risk behaviour on learning processes and best practices that parents, communities and the government can adopt to redress the situation for better adolescents learning. The study was conducted in Kinondoni Municipality, Dar es Salaam Region, where three secondary schools were involved in the study. A cross-sectional design was used. The respondents included the students, teachers, and parents/guardians of the students. Purposive, random, and convenient sampling techniques were deployed to obtain a sample for the study. Data were gathered through structured interviews and questionnaires. Data collected through surveys were analyzed by using Statistic Package for Social Science (SPSS) version 20 software. Furthermore, thematic analysis was used to analyze qualitative data, which were collected from interview. The study findout different factors that influence adolescent sexual behaviour. These factors include; use of alcohol, lack of proper sexual knowledge, poor parental-adolescent communication, and peer influence. Furthermore, the study found out that failure in examination, school dropouts, unwanted pregnancies and STDs, and poor concentration in school were the impacts of adolescents' sexual behaviour on learning. In exploring strategies to be used to address the problem, the study found out that; sexual and reproductive health education, active monitoring of the use of ICT by adolescents, improving parental-adolescents communication and discouraging traditions and customs that lead into sexual risk behaviours were the best strategies to be used to prevent the effects brought by adolescence sexual risks behaviour in academic and social life arena. The study recommends that students support services should be provided in all schools and communities to provide guidance and counseling to adolescents to help them cope better with their social and economic environment without losing their goals in life. Also, curriculum developers should include issues of sex education in curriculum objectives and content, to make sure that the adolescents have the right information that can allow them to make informed choices and evidence-based decisions for safeguarding their lives.
Modelling and analysis of a holling type ii stage structured predator-prey system in the presence of harvesting
(University of Dar es Salaam, 2018) Lyimo, Jacob
This study, developed and analyzed a stage structured predator-prey system in the presence of harvesting, whereby both involved species grow logistically and prey grows in two stages that is; immature and matured prey. Only matured prey species are consumed by predator and harvested. The aim is to analyze the effect of Harvesting and Predation on a Stage structured Predator-Prey system. It is shown that the solutions of the system are positive and bounded. The two populations co-exist if prey's growth rate, predator's growth and capturing rates are greater than, the threshold value R, it's death rate and threshold value A respectively. Local and global stabilities of all possible equilibrium points are discussed. The results show the co-existence equilibrium point is locally asymptotically stable whenever interior equilibrium point exists and predator's capturing rate is less than one. Also it is globally asymptotically stable if predator's growth rate is greater than death rate, the predator efficiency to convert prey biomass into fertility is less than one and prey's growth rate is less than the sum of harvesting and death rates. Finally some numerical solutions are carried out to support the analytic results. The results show that, predation and harvesting have negative impacts on population dynamics of predator-prey system.
The effect of forest fragmentation on pollination ecology of alsodeiopsis schumannii (engl.) engl. in aman nature forest reserve
(University of Dar es Salaam, 2020) Godfrey, Florence
The effect of forest fragmentation on pollination ecology of alsodeiopsis schumannii (engl.) engl. in aman nature forest reserve Tanzania Florence Godfrey MSc(Biodiversity Conservation) University of Dar es Salaam, CoNAS,2020 Pollination is an ecosystem service that is essential in maintaining regeneration of plants and stable plants community. Pollination can be affected by forest fragmentation as it may result in habitat loss for potential pollinators. This study aimed at investigating the effect of forest fragmentation on diversity and abundance of its potential pollinators, visitation frequency as well as fruit set of Alsodeiopsis schumannii. The study was conducted in Amani Nature Forest Reserve (ANFR) and took place in two types of forests, namely continuous forest and forest fragments. Three study sites were selected in each forest type, taking into account availability and abundance of A. schumannii flowering trees. It involved three activities that are visual observation, insect trapping and exclusion bagging experiment. In visual observation, 16 inflorescences observed per day and each observation lasted for 20minutes. Insect trapping involved 96 traps placed near flowering branches and another 96 traps placed in non-flowering branches. In exclusion bagging experiment,pre-receptive inflorescences were subjected to either of 3 treatments, 60 in course mesh bags, 60 in fine mesh bags and 60 inflorescence as open treatment. Findings showed that the flower visitors were members of arthropod orders Hymenoptera,Diptera, Coleoptera, Thysanoptera, Hemiptera, Blattodea, Araneae, Orthoptera,Neuroptera and Lepidoptera. The diversity of flower visitors was significantly higher in forest fragments (H-3.345) than in continuous forest (H’=3.109) i.e. Diversity ttest, t = -3.0143, df = 874.64, p < 0.05). Potential pollinators were Hymenoptera i.e.Meliponula sp, Apis sp followed by Diptera i.e. Drosophilae on the basis of their visitation frequency on A. schumannii inflorescences. The difference in visitation frequency of potential pollinators between continuous forest and forest fragments was not significantly different (Chi square test, x2i = 0.005918, n=2, p > 0.05). The number of fruit set was significantly higher in continuous forest than in forest fragments (Two sample t-test, t =2.956, nl-15, n2= 15, p < 0.05). From these results it can be concluded that Meliponula sp. and sp. are the potential pollinators of the tree species and also forest fragmentation did not lower diversity and abundance of flower visitors.
Production and nutritional quality of amaranthus genotypes under different soil moisture regimes
(University of Dar es Salaam, 2020) Daffa, Halima Salimu
Production and nutritional quality of amaranthus genotypes under different soil moisture regimes Halima Salimu Daffa MSc. (Applied Botany) University of Dar es Salaam, College of Natural and Applied Science, 2020 Information on the effects of soil moisture on productivity and nutritional quality of amaranthus genotypes is limited in Tanzania. This study was conducted to assess the effects of soil moisture on yield and nutritional quality of amaranths genotypes. Experiments were carried out at World Veg in Arusha from April to August 2018 with three irrigation frequencies (once every two weeks, once every week and twice a week) and at MARC in Dar es Salaam from February to June 2019 with four irrigation frequencies (once every two weeks, once every week, twice every week and once a day). Six amaranthus genotypes as subplots (Madiira 1, AH-TL-Sel, Mchicha, Local, Madiira 2 and BRESIL (B)-Sel) were tested in a split plot arrangement in RCBD with 4 replications. From pot experiment, the highest dry vegetative marketable yields were from ‘Madiira 1’ and Local with 19.4, 17.5 and 15.8g/plant respectively when irrigated twice every two week whereas the lowest was from AH-TL-Sel (4.9g/plant) at once every two weeks irrigation frequency. On other hand the field experiment the highest dry vegetative marketable yield were from AH-TL-Sel, ‘Madiira 2’ and ‘Madiira 1’ with 20.64, 14.42 and 13.75g/plant respectively from plots irrigated twice every week while the lowest yield was from BRESIL (B)-Sel (7.86g/plant) from plots irrigated once every two weeks. Twice a week irrigation frequencies from both experiment resulted higher grains yield in AH-TL-Sel, Mchicha and BRESIL (B)- Sel with 16.9, 16.66 and 14.14g/plant in pots and 14.39, 15.25 and 19.69g/plant in the field experiment. The lowest grains yield was from local genotype with 1.47g/plant and 3.64g/plant from the pot and field experiments respectively when irrigated once every two weeks. The highest iron contents were from local and BRESIL (B)-Sel with 296.66 and 292.13mg/100g at once a week and once every two weeks respectively from pot experiment whereas from the field experiment BRESIL (B)-Sel had higher iron of 254.59mg/100g when irrigated once every two weeks. Crude protein was found higher in genotypes BRESIL (B)-Sel and AH-TL-Sel grains from both pot and field experiments with 26.25 and 24.74% (pot) and 41.36% and 3.45% (field) respectively. The lowest crude protein was from Madiira 2 with 8.64% and 8.05% from pot field experiment respectively. Subject
Mathematical modelling of cholera tbreaks in Dar es Salaam with optimal control
(University of Dar es Salaam, 2017) Mugendi, Masakwa
Cholera is a water born disease that affects the small intestine by strain of bacteria known as V. cholera. Since its first outbreak in 1817 in India, cholera epidemics has been a great concern in developing countries. Following 2015 cholera outbreaks in Dar es Salaam, researchers have shown relentless effort in finding the optimal control in the disease transmission. In this research we adopt and analyse Mukandavire et al. (2011) model which was used to study cholera transmission dynamics. Mathematical analysis reveals that the disease free equilibrium point is both asymptotically and globally stable when the reproduction number is less than one. Also, the analysis shows that the endemic equilibrium point is both asymptotically and globally stable when the reproduction number is less than one. Also, the analysis shows that the endemic equilibrium point is asymptotically stable when the reproduction number is greater than one. The model was then extended by including five time dependent controls with the aim of minimizing the total number of infected individuals. Results from numerical simulation of optimal control shows that simultaneous application of vaccination, antibiotic treatments, water treatments, water treatments and provision of clean water can effectively eliminate cholera in Dar es Salaam. With a combination of these controls, the epidemic period was found to take fifteen days with more than fifty percent averted infection cases. Based on the results found we recommend that, health institutions should consider a combination of these controls as a solution to future cholera outbreaks in Dar es Salaam.
Surface carbon formation on reforming catalysts
(University of Dar es Salaam, 1980) Mkayula, Lupituko Luko
The deactivation of platinum on alumina (PtA1203) reforming catalyst by carbonaceous materials called coke, is a significant industrial economic problem. In this work the kinetics of surface carbon formation of these carbonaceous materials has been studied, from C3 and C4 hydrocarbons feed stocks, at atmospheric pressure and in the temperature range of 450- 600 OC. The carbon formation process was monitored using a microbalance capable of detecting up to 10-6 g by weight of the carbon uptake. The effluent gases from the reactor were analysed on line with a gas chromatograph to detect possible intermediates in the cooking process. Surface area, metal area, pore size distribution, scanning and transmission electron microscopies, X-ray fluorescence analysis and energy dispersive analysis of X-rays were techniques employed to characterize the catalyst. The kinetic results have been interpreted using both Froment and Langmuir- Hinshelwood models. The rate of carbon deposition increased with increase in the hydrocarbon partial pressure and also temperature. The rate decreased with increase in the hydrogen partial pressure. The orders for carbon formation reaction seemed to be slightly temperature sensitive, in spite of the apparent linear relationship between the rate of carbon formation and the reciprocal of the absolute temperature from which activation energies were evaluated. Thus, the orders with respect to hydrocarbons increased as the temperature increased, while the orders with respect to hydrogen varied from one temperature to another. Similarly, the deactivation function orders obtained according to Froment model, increased as the temperature increased. This has been explained in terms of changes in mechanism due to the observed structural changes of the catalyst and extent of carbon deposition. The rates of carbon formation were also retarded by increasing the partial pressure of a paraffin while keeping the partial pressure of the olefin counterpart and of hydrogen, constant. A survey of the literature on catalytic carbon formation has been included in the introduction and the results of the present work have been compared with results in other systems.
On Hilbert functions and H-vectors of graded modules for finite sets of points in projective space
(University of Dar es Salaam, 2018) Mgani, Damas Karmel
In this research, we study the Hilbert functions and h-vectors of graded modules with support on finite sets of points in projective space, P_k^n To attain this, we construct the graded modules from the sets of points in projective space. For example, taking X as the set of points, we define an ideal Ix to be the homogeneous ideal in R generated by all forms vanishing at all points of X, and RX: = R/Ix the homogeneous coordinate ring of X. We use a computer software package for algebraic computations Macaulay 2 to study the Hilbert functions, h-vectors and the resulting Betti diagrams of the constructed graded modules. We then concentrate on proving the following three main results. First, we prove that the degree of a homogeneous ideal J for which RX/J is Artinian is the initial degree of the minimal generator(s) of J. This is done by studying the Hilbert function of a homogeneous coordinate ring RX/J. Apart from an ideal J we construct monomial ideals I, I* ⊆ RX then we investigate the structure of the resulting quotient rings. In addition, we prove that a submodule of torsion less module is torsion less. Second, we study the relationship between h-vectors of graded modules and structure of the associated Betti diagrams. Lastly, we present some characterizations of torsion less and reflexive modules over Noetherian rings and integral domains.
The role of geographical information system in effective reduction of non-revenue water in Sumbawanga, Tanzania
(University of Dar es Salaam, 2019) Gwao, Mathew
Inadequate water services in urban and rural areas are challenges, especially in developing countries. In Tanzania, UWSAs are legally mandated to operate since 1998. However, large amount of water seems to be lost as NRW. The study aimed to apply geographical Information System in identifying the causes of physical and apparent losses contributing to NRW and its reduction in the water distribution network, in selected Sumbawanga urban zones, serviced by SUWASA. Experimental measurements were carried out to obtain data for water flow in the system. The survey methods was used to collect data to determine the factors behind physical and apparent water losses. The analysis was carried out by ArcGIS version 10.4 and SPSS version 20.0.Maps, suc as illegal connection hotspots, pressure distributions, DEM, pipes of poor quality materials, pipes prone to leakages and suitable areas for installing AVRs to reducing NRW caused by pressure were generated. For maintenance and planning of water assets to reduce NRW, Postgres and PostGIS software were used to create geo-database. Letter, the geodatabese was connected to QGIS for visualization. Method for determining NRW quantity has been abstracted from IWA. Experimental results indicate around 8787.6 m3, 10718.3 m3, 14637.1 m3 is consumed in zone A, B, and C respectively per month, while computations results revealed that average of 15.15%, 40.2%, 24.52% of water is lost as NRW contributed by physical and apparent loss for zone A, B, and C respectively within six month period. Spatial and non-spatial analyses on the causes of NRW indicate that high pressure, poor quality of pipe materials and aged pipes were the main factors contributing to physical losses while illegal connections and aged maters of class A and B contribute to apparent losses. It is recommended that ARVs and PRVs should be installed at undulating terrain to reduce water pressure. Timely maintenance of water infrastructure offers profound benefits. For instance, aged pipes should be replaced with new pipes, poor quality pipes replaced with class C pipes for services lines to reduce physical losses, whilst aged meters accounting for apparent losses replaced with new ones.

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