494 research outputs found

    Planning a Family:priorities and concerns in rural Tanzanmia

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    A fertility survey using qualitative and quantitative techniques described a high fertility setting (TFR 5.8) in southern Tanzania where family planning use was 16%. Current use was influenced by rising parity, educational level, age of last born child, breastfeeding status, a\ud preference for longer than the mean birth interval (32 months), not being related to the household head, and living in a house with a tin roof. Three principal concerns amongst women were outlined from the findings. First, that there is a large unmet need for family planning services in the area particularly among teenagers for whom it is associated with induced abortion. Second, that family planning is being used predominantly for spacing but fears\ud associated with it often curtail effective use. Third, that service provision is perceived to be lacking in two main areas — regularity of supply, and addressing rumours and fears associated with family planning. Reproductive health interventions in the area should ultimately be more\ud widespread and, in particular, abortion is highlighted as an urgent issue for further research.\ud The potential for a fast and positive impact is high, given the simplicity of the perceived needs of\ud women from this study. (Afr J Reprod Health 2004; 8[2]:111-123)\u

    TDZ AND 4-CPPU in Gamborg B5 salts with MS vitamins doubles embryogenic 191 response from male flowers of EA-AAA banana.

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    Conventionally, auxins have been used in MS medium in combination or without purine-based cytokinins for induction of embryogenesis in EA-AAA banana (Musa spp.). Besides, low embryogenic response, it has been rare for more than two cultivars to respond similarly to a single treatment. This study investigated the efficacy of urea-type cytokinins, N-phenyl-N’-1,2,3-thidiazol-5-ylurea (TDZ) and N-(2-chloro-4-pyridyl)-N'-phenylurea (4-CPPU); and salt formulations, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN, SH and White for embryogenic callus induction in different EA-AAA banana cultivars. Immature male flowers of cultivars Mpologoma, Mbwazirume, Nakabululu, Nakinyika and Nfuuka were cultured on callus induction medium, supplemented with different TDZ and 4-CPPU combinations. Most of the cultivars had embryogenic response to the medium with 10μM TDZ+10μM CPPU. Cultivar Nakabululu recorded 22.2% embryogenic response, followed by Mwazirume (5.7%), Nakinyika (5.3%) and Mpologoma (4.6%). Cultivar Nfuuka had 9.1% embryogenic response on 15μM TDZ+15μM CPPU. When cultivars Mpologoma and Nakinyika were cultured on the same medium containing 10μM TDZ+10μM CPPU, but the MS salts substituted with the other salt formulations, their cultures recorded 11.4 and 8.3% embryogenic response, respectively to Gamborg B5 salts; which was almost twice their response to MS medium. The results suggested that TDZ and 4-CPPU, particularly in Gamborg B5 salt formulation, could increase percentage of embryogenic callus induced from male flowers of EA-AAA banana cultivars, and would improve plant regeneration and consequently help in the process of genetic improvement of EA-AAA banana.Key Words: Cytokinins, embryogenic response, Musa spp., Thidiazuro

    Agrobacterium mediated transformation of banana (Musa sp.) cv. Sukali Ndiizi (ABB) with a modified Carica papaya cystatin (CpCYS) gene

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    Conventional banana breeding for pest and disease resistance is a very difficult and slow process due to the limited sources of resistance, sterility of cultivated banana varieties, high polyploidy levels, long cropping cycle and the lack of rapid screening methods. Molecular breeding using the transgenic approach with candidate genes such as cystatins offers an alternative method to banana improvement. Cystatin proteins inhibit the activity of cysteine proteases responsible for the breakdown of dietary proteins in the gut of many pests including nematodes resulting in protein deficiency. In this study, the papaya cystatin gene was introduced into the banana genome. Embryogenic cell suspension (ECS) cultures of the banana cultivar Sukali Ndiizi (ABB) were used as explants material for the successful transformation of banana. The Carica papaya cystatin gene (CpCYS-Mut89) previously modified to improve its inhibitory potential against banana pests was introduced into this cultivar using Agrobacterium tumefaciens, strain LBA4404 and the gus reporter gene was used to observe successful transformation process. We report the successful protocol for routine transformation of this cultivar, which was completed in six months with plant regeneration observed at a frequency of 23%. An additional four months was required to multiply the regenerant lines in order to have at least 20 plants per line for downstream challenging studies. Putatively transgenic plants were analyzed by PCR using hpt and CpCYS-Mut89 specific primers to confirm the presence of transgenes. Out of 28 selected lines, 27 were positive for both hpt and CpCYS-Mut89 transgenes giving 96.4% transformation efficiency. Five lines were then selected on the basis of putative PCR positives and a Southern blot analysis gave hybridization signals with 1 to 4 copy number integration patterns characteristic of Agrobacterium mediated transformation. These results confirm stable gene integration in East African banana cultivar cv. Sukali Ndiizi (genome group ABB) through an efficient Agrobacterium-mediated transformation protocol described for routine use in future improvement of this crop with genes of economic importance.Keywords: Cystatins, banana, Agrobacterium mediated transformation, southern blotAfrican Journal of Biotechnology Vol. 12(15), pp. 1811-181

    Transient expression of ß-glucuronidase in recalcitrant Ugandan sweetpotato and putative transformation with two cry genes.

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    Sweetpotato (Ipomoea batatas Lam.) has high potential to contain hunger, malnutrition and poverty in sub-Saharan Africa (SSA), since it gives early yield with few inputs. However, productivity of the crop in Africa is very low due to various challenges, such as severe viral diseases and increasing attacks by sweetpotato weevils, Cylas puncticollis and C. brunneus. Effective resistance to weevils has not been identified in the sweetpotato gene pool. On the other hand, the weevil-resistance genes, cry7Aa1 and cry3Ca1 were assembled into a plasmid vector for use in genetic transformation of African sweetpotato cultivars. The parameters for efficient transfer of these genes and the conditions for de novo regeneration optimised in preliminary studies were used in the genetic transformation of Ugandan landrace ‘Kyebandula’ with Agrobacterium tumefaciens EHA 105 harbouring the plasmid pCIP84, which contains cry7Aa1, cry3Ca1 and nptII in its T-DNA. Fifty-four percent of the explants formed adventitious buds. With a mean of 7 buds formed per explant, 6.0% explants formed shoots with a mean of one shoot per explant for those explants that formed shoots on medium containing 50 mg L-1 kanamycin as a selection agent. PCR analysis using primers for cry7Aa1 showed that the transformation efficiency could be as high as 2%. These data highlight the potential of genetic transformation in transferring resistance genes and pave way for enhancement of food security through production of adapted sweetpotato weevil resistant cultivars.Key Words: Agrobacterium tumefaciens, b-glucuronidase, Ipomoea batata

    Improving decision making in schools through teacher participation

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    The hierarchical structure that places head teachers at the apex of a pyramid of staff is a common feature in secondary schools in Kenya. In this arrangement, school heads are poised to use their superior knowledge and experience to direct and control the working of the entire school. This negatively affects efficiency and productivity of the schools because teachers work at half steam because they are not effectively involved in decision making to make them feel as part of the schools. Owing to the dynamics of professionalism and diversity of ideas in secondary schools occasioned by staffing schools with professionally trained teachers and the need to decentralize decision making to the lower levels, the hierarchical structure in management of schools is challenged. On many occasions head-teachers have been advised to involve teachers in decision making as a way of motivating them and to create a feeling of belonging. This study was designed to investigate the extent to which teachers were involved in decision making in comparison to their desired extent of participation. An ex-post facto study was designed. One hundred and twenty three teachers responded to the participatory decision making questionnaire. Data were analyzed quantitatively and qualitatively. It was found that teachers desired greater involvement in decision making than they were currently involved. It was recommended that school managers should increase the extent to which they involve teachers in decision making to improve on the quality of decisions and boost their morale in their performance of duty

    TDZ AND 4-CPPU IN GAMBORG B5 SALTS WITH MS VITAMINS DOUBLES EMBRYOGENIC RESPONSE FROM MALE FLOWERS OF EA-AAA BANANA

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    Conventionally, auxins have been used in MS medium in combination or without purine-based cytokinins for induction of embryogenesis in EA-AAA banana ( Musa spp.). Besides, low embryogenic response, it has been rare for more than two cultivars to respond similarly to a single treatment. This study investigated the efficacy of urea-type cytokinins, N-phenyl-N\u2019-1,2,3-thidiazol-5-ylurea (TDZ) and N-(2-chloro-4-pyridyl)-N\u2019-phenylurea (4-CPPU); and salt formulations, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN, SH and White for embryogenic callus induction in different EA-AAA banana cultivars. Immature male flowers of cultivars Mpologoma, Mbwazirume, Nakabululu, Nakinyika and Nfuuka were cultured on callus induction medium, supplemented with different TDZ and 4-CPPU combinations. Most of the cultivars had embryogenic response to the medium with 10\ub5M TDZ+10\ub5M CPPU. Cultivar Nakabululu recorded 22.2% embryogenic response, followed by Mwazirume (5.7%), Nakinyika (5.3%) and Mpologoma (4.6%). Cultivar Nfuuka had 9.1% embryogenic response on 15\ub5M TDZ+15\ub5M CPPU. When cultivars Mpologoma and Nakinyika were cultured on the same medium containing 10\ub5M TDZ+10\ub5M CPPU, but the MS salts substituted with the other salt formulations, their cultures recorded 11.4 and 8.3% embryogenic response, respectively to Gamborg B5 salts; which was almost twice their response to MS medium. The results suggested that TDZ and 4-CPPU, particularly in Gamborg B5 salt formulation, could increase percentage of embryogenic callus induced from male flowers of EA-AAA banana cultivars, and would improve plant regeneration and consequently help in the process of genetic improvement of EA-AAA banana.Conventionnellement, les auxines ont \ue9t\ue9 utilisees dans le medium MS en combinaison avec ou sans cytokinines \ue0 base de purine pour induction de l\u2019embryogen\ue8se dans la banane EA-AAA ( Musa spp.). En plus d\u2019une faible r\ue9ponse embryog\ue9nique, il a \ue9t\ue9 rare pour plus de deux cultivars de r\ue9pondre de fa\ue7on similaire \ue0 un seul traitement. Cette \ue9tude a \ue9t\ue9 conduite pour \ue9valuer l\u2019efficacit\ue9 des cytokinines de type urea, N-phenyl-N\u2019-1,2,3-thidiazol-5-ylurea (TDZ) et N-(2-chloro-4-pyridyl)-N\u2019-phenylurea (4-CPPU)\ua0; et les formulations du sel, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN, SH et blanc pour l\u2019 induction du callus embryog\ue9nique dans diff\ue9rents cultivars de banane EA-AAA. Des cultivars Mpologoma des fleurs males immatures Mbwazirume, Nakabululu, Nakinyika et Nfuuka \ue9taient cultiv\ue9s sur le medium d\u2019induction du callus, suppl\ue9ment\ue9e avec diff\ue9rentes combinaisons de TDZ et 4-CPPU. La plupart des cultivars avaient une r\ue9ponse embryog\ue9nique au medium avec 10\ub5M TDZ+10\ub5M CPPU. Le cultivar Nakabululu a r\ue9alis\ue9 22.2% de r\ue9ponse embryog\ue9nique, suivi de Mbwazirume (5.7%), Nakinyika (5.3%) et Mpologoma (4.6%). Le cultivar Nfuuka avait 9.1% de r\ue9ponse embryog\ue9nique sur 15\ub5M TDZ+15\ub5M CPPU. Lorsque les cultivars Mpologoma et Nakinyika \ue9taient cultiv\ue9s sur le m\ueame medium contenant 10\ub5M TDZ+10\ub5M CPPU, mais les sels MS substitu\ue9s par d\u2019autres formulations de sels, leurs cultures ont enregistr\ue9 11.4 et 8.3% de r\ue9ponses embryog\ue9niques, respectivement, aux sels Gamborg B5; qui faisait presque le double de leur r\ue9ponse au medium MS. Les r\ue9sultats ont sugg\ue8rent que TDZ et 4-CPPU, particuli\ue8rement dans la formulation du sel Gamborg B5, pourrait augmenter le pourcentage induit du callus embryog\ue9nique des fleurs males des cultivars de banane EA-AAA et pourrait am\ue9liorer la r\ue9g\ue9n\ue9ration des plants et en cons\ue9quence aider dans le processus de l\u2019am\ue9lioration g\ue9n\ue9tique de la banane EA-AAA

    The Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction across a tunneling junction out of equilibrium

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    The Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between two magnetic ss-dd spin impurities across a tunneling junction is studied when the system is driven out of equilibrium through biasing the junction. The nonequilibrium situation is handled with the Keldysh time-loop perturbation formalism in conjunction with appropriate coupling methods for tunneling systems due to Caroli and Feuchtwang. We find that the presence of a nonequilibrium bias across the junction leads to an interference of several fundamental oscillations, such that in this tunneling geometry, it is possible to tune the interaction between ferromagnetic and antiferromagnetic coupling at a fixed impurity configuration, simply by changing the bias across the junction. Furthermore, it is shown that the range of the RKKY interaction is altered out of equilibrium, such that in particular the interaction energy between two slabs of spins scales extensively with the thickness of the slabs in the presence of an applied bias.Comment: 38 pages revtex preprint; 5 postscript figures; submitted to Phys. Rev.

    Agrobacterium mediated transformation of banana (Musa sp.) cv. Sukali Ndiizi (ABB) with a modified Carica papaya cystatin (CpCYS) gene

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    Conventional banana breeding for pest and disease resistance is a very difficult and slow process due to the limited sources of resistance, sterility of cultivated banana varieties, high polyploidy levels, long cropping cycle and the lack of rapid screening methods.Molecular breeding using the transgenic approach with candidate genes such as cystatins offers an alternative method to banana improvement. Cystatin proteins inhibit the activity of cysteine proteases responsible for the breakdown of dietary proteins in the gut of many pests including nematodes resulting in protein deficiency. In this study, the papaya cystatin gene was introduced into the banana genome. Embryogenic cell suspension (ECS) cultures of the banana cultivar Sukali Ndiizi (ABB) were used as explants material for the successful transformation of banana. The Carica papaya cystatin gene (CpCYS-Mut89) previously modified to improve its inhibitory potential against banana pests was introduced into this cultivar using Agrobacterium tumefaciens, strain LBA4404 and the gus reporter gene was used to observe successful transformation process. We report the successful protocol for routine transformation of this cultivar, which was completed in six months with plant regeneration observed at a frequency of 23%. An additional four months was required to multiply the regenerant lines in order to have at least 20 plants per line for downstream challenging studies. Putatively transgenic plants were analyzed by PCR using hpt and CpCYS - Mut89 specific primers to confirm the presence of trans genes. Out of 28 selected lines, 27 were positive for both hpt and CpCYS - Mut89 transgenes giving 96.4 % transformation efficiency. Fivelines were then selected on the basis of putative PCR positives and a Southern b lot analysis gave hybridization signals with 1 to 4 copy number integration patterns characteristic of Agrobacterium mediated transformation. These results confirm stable gene integration in East African banana cultivar cv. Sukali Ndiizi (genome group ABB) through an efficient Agrobacterium - mediated transformation protocol described for routine use in future improvement of this crop with genes of economic importance
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