283 research outputs found

    Hybridization between Tilapia zillii (Gervais) and Tilapia andersonii (Casteinau) at the Freshwater Fisheries Institute, at Nyegezi, Tanzania

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    As a part of an overall project on fishculture development techniques in Tanzania, hybridization between Tilapia zillii and Tilapia andersonii was carried out at the Freshwater Fisheries Institute, Nyegezi, Tanzania. T. andersonii, a plankton feeder, is not indigenous to Tanzania but was introduced in 1968 from Zambia for certain specific purpose. T. zillii, a macrovegetation feeder, is present locally and is common. In the present studies T. zillii (245.0 mm/260.0 g) female was hybridized with T. andersonii (288.0 mm/350.0 g) male. Under cement cistern conditions it was only after about four months of acclimatization that hybridization between the two occurred. About 1,637 interspecific hybrid fry were produced in a single brood. Eggs were adhesive and parental care shown by the female, the male being driven away. Growth under cistern conditions was slow, attaining a size of 134.8 mm/44.3 g in 10 months. But this growth rate need not be taken as ideal. In body shape, colouration and other morphometric characters the hybrids had inherited from both parents. The number of gill rakers among the hybrids was eighteen which was intermediate between T. zillii (12) and T. andersonii (27). Among one hundred and seventy two specimens (106.0 mm - 168.0 mm) cut and examined the sex ration was hundred per cent males and all of them were between II and IV stages of maturity. This is the first report of fish hybridization from Tanzania and possibly the first report on hybridization between T. zillii and T. andersonii. The full significanoe of the findings and its role in African fishculture is discussed

    Aspalathin a unique phytochemical from the South African rooibos plant (Aspalathus linearis): A mini Review

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    Aspalathus linearis (rooibos) is a plant which grows in a limited habitat in South Africa. The plant is mainly renowned for the beverage (herbal tea) which is made from its aerial parts. The popularity of the herbal tea is not confined to South Africa as significant amounts of the tea are exported to many countries worldwide. Rooibos reportedly has several health benefits which have been attributed to its constituent phytochemicals. One of the major phytochemicals in rooibos is aspalathin. Aspalathin makes up between 4-12% of the plant. Aspalathin is a dihydrochalcone glycoside which has thus far only been isolated from Aspalathus linearis. Aspalathin has been shown to possess biological activity which imparts it with multiple health beneficial effects. This mini review highlights the recent findings on the biological properties of aspalathin. These include antioxidant, antidiabetic, cardioprotective, antihypertensive and antimutagenic effects. Given its multiplicity of biological effects, aspalathin is a natural phytochemical which has potential to be incorporated into current medical therapeutic regimes in light of recent preferences for the use of natural medicines

    Growth rates of Tilapia esculenta Graham and Tilapia zillii (Gervais) under cultivation in ponds at Nyegezi, Tanzania.

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    Aquaculture in Tanzania is still on a subsistence level and most of the ponds are maintained as a part time job. The ponds are too small, shallow and over crowded with stunted tilapia spp. In the present paper the results of experi ments conducted in ponds at Nyegezi with T. esculenta and T. zillii are presented. This was part of an overall project of developing techniques of fish culture with Tilapia under the limitted existing conditions at Nyegezi. In a mono -species culture experiment with Tilapia zilli~, in nihe month's time an average size of 172.8 mm/ 115.0 g was attained. In another experiment with T. zillii and T. ~ lenpa in thirteen month's time, T. zillii attained an average size of 180.2 rom/ 106.6 g and T. escu1enta 193.6 mm/ 118.8 g. In another experiment with intensive feeding schedule an average si.ze of 179.3 mm/ 126.6 g was attained by T. zillii and 191.0 rom/ 125.0 g by T. esoulenta, in four month's time

    Growth rates of Tilapia esculenta (Graham) and Tilapia zillii (Gervais) under cultivation in ponds at Nyegezi, Tanzania

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    Aquaculture in Tanzania is still on a subsistence level and most of the ponds are maintained as part time job. The ponds are too small, shallow and over crowded with stunted Tilapia spp. In the present paper the results of experiments conducted in ponds at Nyegezi with T. esculenta and T. zillii are presented. This was part of an overall project of developing techniques of fish cultures with Tilapia under the limited existing conditions at Nyegezi. In a mono - species culture experiement with Tilapia zillii in nine month's time an average size of 172.8 mm/115.0 g was attained. In another experiment with T. zillii and T. esculenta in thirteen month's time, T. zillii attained an average size of 180.2mm/106.6 g and T. esculenta 193.6 mm/118.8 g. In another experiment with intensive feeding schedule an average size of 179.3 mm/126.6 g was attained by T. zillii and 191.0 mm/125.0 g by T. esculenta in four month's time. A locally prepared supplimentary feed with local Brewery Waste and Fish Meal (10:1) was readily accepted by both species of Tilapia. T. zillii voraciously fed on Cabbage leaves, Cauliflower leaves, Chinese cabbage leaves, Cassava leaves and on the common weed Comalina sp. Though all the items mentioned above were readily accepted by T. zillii feeding with Comaltna sp. was the easiest and most convenient because of its availability. In an intensive feeding experiment with vegetable leaves/Comalina sp. and the locally prepared supplimentary feed the fishes attained table size in four months time. Cement cistens of 5 X 3 X 1½ m size could be conveniently used for breeding both species of Tilapia. T. zillii had semi adhesive eggs and they were deposited on the sides of the cement wall. The number of young ones in a brood ranged from 160 to 314 in T. esculenta and 687 to 4,356 in T. zillii

    Preliminary observations on cage culture of Tilapia esculenta Graham and Tilapia xillii (Gervais) in Lake Victoria waters, at the Freshwater Fisheries Institute, Nyegezi, Tanzania

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    Cage culture of Tilapia is not suggested as a substitute for any known techniques in fish culture, but as one of the various techniques of obtaining more fish under controlled conditions. This fact has been very well accepted in various countries. Whererever facilities exist, this line of fish culture should be vigorously explored as a possible avenue in increasing fish production. High density stocking, management under controlled conditions, easy technique of fabricating the cage at relatively low cost, having no demand on land area, absence of prolific and effective breeding and easy availability of fish when a person needs it are a few of the attractions of the technique. The studies indicate that it is desirable to have different meshes for the cages, such as, small meshed cages for rearing fry to fingerlings stages, and larger meshed cages for rearing fingerlings to table sized fishes. II' the meshes are small, the resistance will be more and less water wilt pass through. While feeding with powdered food material, because of brisk activity of feeding fish, a part of the feed appeared wasted. This can be easily overcome if we would resort to feeding fish with cheap pelleted feeds which will no doubt reduce wastage. Precaution has to be taken against damage of the net and thereby loss of fish and against poaching by unauthorised persons. In the present attempt has been demonstrated the possibility of utilizing locally available species of Tilapia for cage culture and obtaining moderately satisfactory growth rates

    Implication of Financial Crimes and Corruption on Manufacturing Firms in Osun State, Nigeria

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    This research work examines the implication of financial crimes and corruption on manufacturing firms with the objective to find a means to minimize or possibly to eliminate the menace of financial crimes and corruption in an organisation and to identifies the consequences or implications of financial crimes and corruptions on manufacturing firm. The sample comprises seventy (70) employees who were randomly selected from different six categories of manufacturing firms in Osun State, Nigeria. Data were collected from both primary and secondary source while the descriptive analysis was used to analyze the data collected with aid of (ANOVA) Analysis of Variance tool to test hypotheses. The results showed that the financial crimes and corruption has significance implication on manufacturing firms and organisations have preventive measures to curb or minimize the incidence of financial crime and corruption. The implications are the needed revenue for development of the firm have drained away and it damage critical management of organisation and scare away both foreign and domestic investors if there are no preventive measure put in place. It was recommended that the executives should ensure that the cases of financial crimes and corruption are reported to EFCC and ICPC and to installed and maintained effective internal control system, policies and operations. Keywords: Financial crime, corruption, money laundry, manufacturing firms, implications.

    Improving growth and productivity of tomato by some biostimulants and micronutrients with or without mulching

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    Two field experiments were doled out during 2014 and 2015 growing seasons to assess tomato growth and yield as affected by some biostimulants and micronutrients with or without mulching type. Certain physiological characters were also examined, plant height, the number of branches per plant chlorophyll a, nitrogen %, red fruit weight and total yield per plant as well as fruit firmness and ascorbic acid concentration in fruit was increased in tomatoes under black plastic mulch compared with bar soil. Application of either biostimulants or micronutrient used to increase all growth and yield characters as well as photosynthetic pigments, ions percentage, and fruit quality. Additive effects were shown under mulching, seaweed extract proved to be the most effective in this respect. It could be recommended that spraying tomato crop at 35 and 50 days from transplanting with 500 mg/l seaweed extract under clear or black plastic mulch in order for inducing the highest yield and improve fruit quality

    Distribution of culturable endophytic bacteria in lemon grass (Cymbopogon citratus)

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    Endophytic bacteria are currently being harnessed as potential sources of bioactive compounds, potential biofertilizers, and as tools for bioremediation. This therefore stresses the importance of searching for these noble bacteria in various plants. In the present study, fresh and apparently healthy leaves and roots of lemon grass were collected and surfacesterilized using 70% (v/v) Ethanol, 3% sodium hypochlorite solution and sterile distilled water. Isolation of endophytic bacteria was achieved using culture technique, while identification was done based on morphological, biochemical and microscopic characteristics. A total of 16 endophytic bacteria were isolated and identified as Bacillus spp. (3 isolates), Escherichia coli (1 isolate), Klebsiella pnuemoniae (3 isolates), Micrococcus spp. (3 isolates), Pseudomonas spp. (1 isolate), Rhizobium (2 isolates) and Staphylococcus aureus (3 isolates). The root portions of the plant harbour 10 (62.5%) of the entire endophytic bacteria isolated, while the leaves harbour the remaining 6 (37.5%). Gram negative rod- shaped bacteria are the dominant of all the bacteria in the roots (50%), whereas, in the leaves, Gram positive cocci are the dominant (50% of all). No Gram negative cocci were isolated from the plant. In conclusion, Lemon grass harbours diverse genera of endophytic bacteria present both in the roots and leaves of the plant, but the roots harbour higher populations of the bacteria.Keywords: Endophytic bacteria, Lemon grass, Root, Leaf, Isolatio

    Multi-port converter for medium and high voltage applications

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    This work presents a multi-port converter (MPC) that is well-suited for use as a hybrid hub in complex multi-terminal high-voltage direct current (MTDC) networks. The proposed MPC generates several and controllable DC voltages from a constant or variable input DC voltage or AC grid. Its operating principle is explained and corroborated using simulations and experimentations

    Yes, size does matter (for cycling safety)! Comparing behavioral and safety outcomes in S, M, L, and XL cities from 18 countries

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    Although most actions aimed at promoting the use of active transport means have been conducted in ‘large’ cities, recent studies suggest that their cycling dynamics could hinder the efforts put into infrastructural, modal share, and cycling culture improvements. Aim The present study aimed to assess the role of city sizes on riding behavioral and crash-related cycling outcomes in an extensive sample of urban bicycle users. Methods For this purpose, a full sample of 5705 cyclists from >300 cities in 18 countries responded to the Cycling Behavior Questionnaire (CBQ), one of the most widely used behavioral questionnaires to assess risky and positive riding behaviors. Following objective criteria, data were grouped according to small cities (S; population of 50,000 or fewer), medium cities (M; population between 50,000 and 200,000), large cities (L; population between 200,000 and one million), and megacities (XL; population larger than one million). Results Descriptive analyses endorsed the associations between city size, cycling behavioral patterns, and mid-term self-reported crash outcomes. Also, it was observed a significant effect of the city size on cyclists' traffic violations and errors (all p < .001). However, no significant effects of the city size on positive behaviors were found. Also, it stands out that cyclists from megacities self-reported significantly more violations and errors than any of the other groups. Further, the outcomes of this study suggest that city sizes account for cycling safety outcomes through statistical associations, differences, and confirmatory predictive relationships through the mediation of risky cycling behavioral patterns. Conclusion The results of the present study highlight the need for authorities to promote road safety education and awareness plans aimed at cyclists in larger cities. Furthermore, path analysis suggests that “size does matter”, and it statistically accounts for cycling crashes, but only through the mediation of riders' risky behaviors
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