University of Dar es Salaam Library Repository

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Recent Submissions

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Ticks and ticks viral diversity in a wildlife-livestock interface at Mikumi national park, Tanzania
(University of Dar es salaam, 2021-10) Damian,Donath
Areas which lie at the border of Mikumi National Park, Tanzania are considered to be the hotspot for the tick species and possibly tick-borne pathogens, although data on ticks and the diversity of the viruses in ticks are non-existing. Herein, identification of ticks into genus level based on morphological characteristics, the tick burden in cattle and goats based on parasitological parameters, genetic diversity of tick species based on mitochondrion 16S rRNA gene, mean and pairwise genetic variation in ticks based on Kimura 2 parameters model, and the diversity of viruses in ticks using viral metagenomic approach were determined. Using the morphological characteristics, two ticks genera; Hyalomma and Rhipicephalus were identified. Tick burden findings reported the overall proportion of tick-infested animals to be 48.6%; cattle (51.5%) and goats (44.3%) whereas; the overall mean tick intensity and abundance in cattle and goats were 3.9±0.01 and 1.8±0.01 respectively. Based on mitochondrion 16S rRNA gene, six tick species were identified including Rhipicephalus microplus, Rhipicephalus evertsi, Hyalomma rufipes, Hyalomma truncatum, Hyalomma marginatum, and Hyalomma turanicum. The Hyalomma marginatum and Hyalomma turanicum species are reported for the first time from the study area and Tanzania in general. In the genetic variation analysis data it was observed that, Hyalomma marginatum recorded the highest mean (0.04±0.01) and pairwise (0.06) intraspecies distance value whereas, the highest pairwise intragenus value (0.139) was recorded in Hyalomma genus. Notably, high values of 0.11±0.01 and 0.23 mean and pairwise genetic distances respectively in the tick community were recorded. Viral groups related to known viral families; Retroviridae, Flaviviridae, Rhabdoviridae, Chuviridae, Orthomyxoviridae, Phenuiviridae, Totiviridae, Rhabdoviridae, Parvoviridae, Caulimoviridae, Mimiviridae, as well as unknown viral families named as unknown virus 1and 2 were reported. Therefore; intensification of the surveillance of ticks and tick-borne pathogens in Tanzania is highly encouraged to predict future emerging ticks and tick-borne pathogens.
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Determinants of growth and sustainability of local civil and building contractors in construction industry: the case of Dar es salaam city
(University of Dar es salaam, 2021-10) Muro,Erick Rangya
The construction sector has long been one of Tanzania's economic foundations. This study aimed at understanding the determinants that drive the growth and sustainability of local contractors who are the key players in construction industry such that, adjusting measures may be developed to improve their successful involvement in the construction sector. The quantitative research method was applied for this study, and questionnaires were used to conduct surveys among local contractors and government officials in regulatory bodies. Spearman’s correlation test was performed to assess the association of the ranked variables. The results revealed that majority of local contractors are not growing consistently, and also most challenges affecting their growth and sustainability are faced at both company and project levels including unfavourable tax schemes and loan costs, delayed payments and bad debts, lack of network or contacts in the right places and low market share due to introduction of force account procedure. Also, the study discovered that the most effective approaches to growth and sustainability are found at the strategic level, which are networking and maintaining good relationships with clients, acquisition of construction equipment and other bankable assets, maintaining a positive culture in the company, and implementing a formal system for measuring performance. According to the findings of this study, there is a need for local contractors to devote more in the methods outlined at the company level in order to eliminate barriers to growth and sustainability at both levels. The research gives statistical results for local contractors in Tanzania to use in order to improve their growth and sustainability. Keywords: Growth, sustainability, construction industry, local contractors
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Molecular identification and characterization of cassava mosaic begomoviruses (cmbs) in non-crop plants from Unguja and Pemba
(University of Dar es salaam, 2021-10) Mwakosya, Joseph Andongwile
Cassava mosaic begomoviruses (CMBs) cause cassava losses up to 100%. Recently, it has been reported that some of CMBs infecting cassava plants are from non-crop plants. This study identified and characterized CMBs in non-crop plants collected from Unguja and Pemba Islands. A total of 108 symptomatic and asymptomatic non-crop leaf samples were collected. The results of this study confirms the occurrence of four African Cassava Mosaic Virus (ACMV) and seven East African Cassava Mosaic Virus (EACMV) isolates in non-crop plants by using PCR, nanopore MinION sequencing, Sanger sequencing and phylogenetic analysis. Plant DNA barcode genes (rbcL and matK) were used in the identification of non-crop plants harboring CMBs. Through, basic local alignment search tool (BLAST) and phylogenetic analysis Datura stramonium, Solanum incanum, Senna occidentalis, Wild Solanum melongena, Ricinus communis and Sida acuta were identified as non- crop plants that harbour CMBs. Assessment of infectivity of CMBs isolated from Solanum incanum and Sida acuta was done on a model TMS60444 and Chereko susceptible cassava varieties by particle bombardment using rolling cycle amplification products. Mild curling leaves and yellowing mosaic symptoms were observed in seven out of sixteen inoculated plants with ACMV and eight out of sixteen inoculated with EACMV. All symptomatic experimental cassava plants inoculated with both ACMV and EACMV tested positive in PCR using CMBs specific primers. For the first time, the present study documented Solanum incanum as an alternative host of ACMV and Sida acuta as an alternative host of EACMV. Therefore, management efforts to control cassava mosaic disease (CMD) caused by ACMV and EACMV should consider these non-crop plants for sustainable control of these viruses which affect cassava worldwide.
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The impact of land cover change on floristic diversity and aboveground carbon stock in image forest reserve, Tanzania
(university of Dar es Salaam, 2021-11) Kayombo, Canisius John
Evaluating the impact of land cover change on floristic diversity and above ground carbon stock (AGtC ha-1) is important for awareness vegetation condition. A study was done in 2019 to assess the impact of land cover change on floristic diversity and aboveground carbon stock in Image Forest Reserve (IFR). Satellite images from Landsat 5 (TM) and Landsat 8 (OLI) for 1990, 2004, and 2018 were used for image processing of visual and digital image using ArcGIS 10.5 software. Plots of 20 m x 40 m were set at an inter-plot distance of 250 m, on which trees with a diameter ≥ 5 cm were measured. Nested plots of 2 m x 5 m were set for assessing shrubs, saplings, and poles, while 1 m x 1 m subplots were established to assess herbaceous plants, and tree seedlings. Anthropogenic activities were assessed and recorded on a scale of 1-5, where 1-20% was scaled as one (1); 21-40% (2); 41-60% (3); 61-80% (4); ≥ 81% (5). Shannon Wiener Diversity Index (H') was used to calculate diversity index, and Simpson index (Pi2) was used to calculate index of dominance. Tree density, relative density, and basal area were calculated. The identified land covers were forest, woodland, shrubland and grassland, and wooded grassland. Results revealed that from 1990 - 2004 woodland decreased by 577.89 Ha, shrub land and grassland decreased by 830.43 Ha, and wooded grassland decreased by 323 Ha, while forest cover increased by 1,731.96 Ha. Between 2004 - 2018 woodland increased in size by 572.31 Ha, shrub land and grassland cover (831.87 Ha), wooded grassland (313.47 Ha), while forest decreased in size by 1,717.56 Ha. The identified land cover change drivers were logging for timber, grazing, wildfires, encroachment, and snaring. A total of 502 plant species were identified, and woodland had the highest plant species diversity followed by other land covers. Forest had the highest AGtC ha-1 of all others. Tree regeneration varied significantly within the land cover types. The tree regenerants density was higher in forest followed by woodland, and wooded grassland was the least. Trees with a diemeter > 40 diameter had the highest basal area. This information that will enhance conservation strategy of IFR reflected from how land cover types have changed, diversity potential, carbon stocks, trees density and regeneration. Alternative income generating projects, participatory forest management, establishment of woodlots at local communities’ homesteads, and education should be applied to sustain the forest reserve.
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Prerequisites Among Tanzanian Libraries Towards Embracing Emerging Digital Technologies
(Tanzania Library Association, 2023-01) Evans F. Wema
This paper sheds light on current digital trends globally and the position at which libraries in Tanzania should be placed. The paper provides an overview on the ongoing digital transformations worldwide, as well as the position at which libraries have placed themselves. The paper provides an overview on ways by which digital revolution have transformed technology integration into library services, revolutions in LIS education, codes of ethics in libraries and information institutions in the era of digital transformation as well as the position of libraries in the era of cyberspace and information security. The paper provides an overview of the role of libraries in the provision of data and open access information, innovation and networking, new information environment, redesigning library operations to provide sustainable services as well as embracing and coping up with new digital aspects on smart and mobile technologies, virtual library services and marketing of library services using digital technologies. The paper summarizes the discussion by highlighting impending challenges and possible solutions that are important in enhancing library services in the current digital world towards meeting the SDGs.