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The study of state education policy mechanisms and goals in Arizona and California: a comparative analysis
(University of California, Riverside, 1985) Kavishe, Paul Rajabu
The primary purpose of the study was to investigate the goals and mechanisms of education policies in the states of Arizona and California. Specifically, the dissertation examined alternative approaches taken to seven basic state policy mechanisms (SPMs) and the related educational goals pursued by those states. The goal of the study is concep tual and exploratory rather than hypothesis testing. The initial working hypothesis was that educational goals or values control the selection of alternative approaches. Procedurally the study: (1) identifies alternative approaches in each of the seven SPMs; (2) examines and differentiates the educational goals of the key actors; and (3) explores the relationship between the goal preferences of the key actors and the level of attention given to various approaches to policy content. The study is a comparative case study employing three data collection methods: interviews, questionnaires, and pertinent document analysis. Interview respondents included 66 key education actors--34 in Arizona and 32 in California. These were selected from four categories based on their roles within the state educational policy system: appointed officials in both legislative and executive staff offices; elected officials; educational interest group representa tives ; and two knowledgeable observers. The study findings indicated that the identified SPMs accurately describe and classify education policies in the states. Additionally, a relationship was found between the goal preferences of key actors and the state's emphasis on particular policy approaches. From document analysis and interview responses, it was found that among the four educational goals studied (efficiency, equity, quality, and choice), quality surfaced as the critical contemporary issue in both states. The findings of this study may have potential signif icance for both scholars and policy makers. Scholars should benefit from the availability of a taxonomic framework capable of describing and comparing the diverse education policies being pursued by various states, and policy makers, by utilizing the framework, may be able to more quickly identify and evaluate alternative strategies for improving the performance of the public schools.
Influence of mangrove deforestation on nutrition ecology and genetic diversity of uca annulipes along the Tanzania mainland and Zanzibar coast
(Vrije University Brussel, 2000) Alex, Nehemia; Dehairs, Frank; Marc, Kochzius
The quaternary stratigraphy and environments of Olduvai gorge - Tanzania, based on fossil soils and related dating
(VRIJE UNIVERSITEIT BRUSSEL, 2000) Kafumu, Peter .D.
This study reports research results and interpretations based on field geological-stratigraphical- litological-palaeosol sequential studies of Tertiary-Quaternary deposits of Olduvai Gorge (main work), Manonga-Wembere Valley and Holili, (annex work) localities in Tanzania. It is also based on laboratory studies (micromorphology, mineralogy, geochemistry and magnetic susceptibility). Special emphasis is placed on the study of palaeosol levels frequently found in these sedimentary sequences. Geology and stratigraphy In all the three areas, Pliocene-Pleistocene sediments are laid down unconformable on a Precambrian basement complex. A huge unconformity exists between the Precambrian rocks (granite, quartzite and gneiss) and the Pliocene-Pleistocene sediments. The basement is a remnant planation surface, which was formed at the beginning of the Tertiary, often represented by isolated granite kopjes, quartzite and gneiss inselbergs and hills sticking out from the present plain level. In Olduvai Gorge the study revisits the stratigraphy and reveals numerous sediments and palaeosol levels (not earlier reported). These levels and beds are within the earlier recognized general Bed I, II, III, IV, Masek and Ndutu Beds. Bed I (2.2Ma - 1.75Ma) contains at least 43 lithological (clay, sands, gravel, mudstone, limestone and marls) units including palaeosol levels. Bed II (1.75Ma - 1.15Ma) is also a zone of abundant geological depositional environments composed of clay, sand-gravel bed complexes, tuff (ash fall or ash flow), limestone and palaeosol levels. Bed III (1.15Ma - 0.6Ma) is a complex volcano-sedimentary depositional environment marked by lacustrine marly sequences, clay layers, sand-gravel beds and calcarenaceous sediments itercalated by red-brown palaeosol levels. Bed IV and Masek Beds (0.6Ma - 0.4Ma) are not distinguishable in the field and therefore grouped together and names adapted from previous workers. The zone contains about 4 palaeo-Vertisols each developed on a clay layer. Ndutu Bed (0.2Ma and younger) is represented by a series of 7 palaeo-Vertisol levels (similar to the ones in Masek Beds), mudstone, claystone and limestone from bottom to top. Gravel and sand beds across the profile have the highest magnetic susceptibility (MS) values compared to clay, marls, calc-sediments or tuff lithologies. Magnetic susceptibility values of palaeosol levels in sandy units are usually lower than the background values of the sand layers. Palaeosols that developed on clay units have higher MS record than the clay background values. The general MS pattern shows an increasing trend across the stratigraphy from older to younger units. The mineralogical signatures also reflect the general stratigraphical characterization. The lower (Bed 1 and Lower Bed II) stratigraphical unit show higher clay minerals and carbonate concentrations, the middle (Bed II and Bed III) indicate slightly low clay minerals and carbonates abundance and the upper parts of the profile (Masek/Bed IV) show higher concentrations of clay and carbonate minerals. Based on field and some micromorphological studies 57 palaeosol levels are mapped. They are grouped into (a) Red-brown to dark gray palaeosols which are probably palaeo-Alfisols or Ultisols, occur in Upper Bed I, Middle Bed II and Bed III. (b) Olive to gray palaeo-vertisols (Bed I, Masek and Ndutu Beds), (c) Palaeo-Andisols found in Bed I and Bed II are observed to develop on ash fall/flow tuffs and (d) Palaeo-Aridisols are gray to olive palaeosol levels, seem to have developed on sand levels mainly in upper Bed II. Red to brown palaeosols (AlfisoIs/UItisols?) are slightly richer in FeO-Fe2O3 and MnO values than other palaeosol levels. Total soil silica/sesquioxide mole ratios of both palaeo-Alfisols and palaeo-Vertisol resemble modern Alfisols and Vertisols. Micromorphological studies indicate that gray-olive palaeosols (Vertisols, Aridisols and Andisols) contain numerous calcite nodules, calcite coatings/hypocoatings and infillings with rare Fe-Mn hydr(o)xide coatings and nodules. Clay coatings are rare or absent. They commonly show a granostriated or monostriated b-fabric and porphyric c/f related distribution of the basic components. The red-brown and dark gray palaeo-Alfisols contain multiple micromorphological features (red-yellow clay coatings and clay coating fragments, Fe-Mn oxide nodule and coatings with some calcite coatings and in-fillings) that are usually seen, imprinted on one another. Palaeo- Aridsols are regarded to be formed in semi-arid palaeoclimates, while palaeo-Vertisols were formed in alternating wet and dry conditions of the Pleistocene Epoch. The red to brown palaeo- Alfisols are assumed to have developed during wet/humid palaeoclimates in Olduvai Gorge during the Pleistocene. The Manonga-Wembere Valley geology comprises of Pliocene-Pleistocene lacustrine gravel, sands and calcareous-clay deposits and Holocene mbuga clays and alluvial sand. The micromorphology of palaeosol levels from Manonga-Wembere Valley show strong clay illuviation of red to yellow clay coating and clay coating fragments with Fe-Mn (hydr)oxide coatings. The clay coating fragments occur as accumulation of oriented clay-coating fragments in a red to yellow groundmass resembling clay illuviation fronts found in present day warm and humid (Meditterranean) climates. -Manonga-Wembere Valley palaeosol levels are therefore assumed to represent a wet and humid climate and environment during the Pliocene-Pleistocene times. Kaolinite and illite clay minerals together with gibbsite and some zeolites (analcime and stilbite) dominate the mineralogy of these palaeosol levels. The geology and stratigraphy of Holili begins with the Precambrian basement rocks and then covered by lava flows (basalt) of the Kilimanjaro volcanic episode. Then a soil (palaeosol) developed on the basalt. The landscape (palaesol) was finally covered in succession by tuffaceous mudstone and calcareous tuffaceous grit. A hominid tool, fossil leaf impressions of angiosperm dicotyledon flowering plants and animal remains (tooth, horn and canon bone) were recovered in Holili Pleistocene deposits. Palaeoclimatic and palaeoenvironmental variability The palaeoclimatic and palaeoenvironmental variability in Olduvai Gorge, Manonga- Wembere and Holili localities as deduced from facies, magnetic susceptibility, mineralogy, geochemistry, micromorphology and palaeosol occurrences and cyclicities seem to be linked to the global causes of climatic changes. 400ka Gravel beds cyclicity (at about 2.2Ma, 1.76Ma, 1.4Ma, l.OOMa 0.65Ma and 0.2Ma), 40Ka and lOKa palaeosol cyclicity are observed in Olduvai Gorge. The climatic variability of Olduvai Gorge during the Quaternary is found to correlate with that of Greece (Mediterannean). This is evidence that the climate of Olduvai Gorge during the Quaternary also followed global trends. In Olduvai Gorge hominids and other animal fossil remains are frequently found on palaeosols levels or closely associated to palaeosol levels. Long periods of 400Ka marked by gravel bed complexes are generally wet periods. Gravel bed complexes that mark significant short periods of drought in this study are correlated to FAD and LAD of Australopithecus boisei, Homo habilis and Homo erectus hominid species in Olduvai Gorge. Likewise in Manonga-Wembere Valley and Holili deposits animal fossil remains occurrences are associated to palaeosol levels. Future research For future research a complete micromorphological study of all possible palaeosol levels will be helpful in discerning more the climatic variability. Future hominid search would be more successful if palaeosol levels were mapped and followed over long distances. New Ar-Ar dating of the basalt and tuff in Manonga-Wembere Valley and Holili areas would provide better age estimates of the deposits.
A technical evaluation of ten internet search engines for indexing and retrieving scientific literature
(Sokoine University of Agriculture, 2001) Busagala, l. S. P.
Several public Search Engines exist of which their coverage and response time differ. Now which one does perform best under the present connectivity? This study aimed at investigating the information indexing and retrieval effectiveness and efficiency of ten selected search engines under different connection speeds at two University Libraries namely Sokoine University of Agriculture (SNAL) and University of Dar es salaam Library (UDSM). Google followed by Yahoo outnumbered all the other eight-search engines in terms of relevance, precision, and responsiveness. In terms of other features such as phrase searching, simple and natural language interface, high quality of display results, these search engines were the best. MetaSearch engines especially MetaCrawler performed the worst in indexing and retrieving scientific literature particularly at UDSM library. There was a significant difference of search engines performances between the two connection speeds. User information searching skills was notably poor calling an action from information professionals.
Analytical methods for Cyhalofop-butyl and its metabolites in Soil and water
(China academic journal electronic publishing house, 2001) Mwalilino, Jilisa K; L i, Zhao; Guonian, Zhu; Yingxu, Chen
A relatively simp le and less expensive m ethod is p ropo sed fo r the determ ination of cyhalofop2butyl (XDE2537) and its m etabo lites: R2(+ ) 222[ 42(22fluo ro242 cyanophenoxy) phenoxy ] p ropano ic acid (AC ID ); R2(+ ) 222[42 (42 carboxyl222fluo ro242 cyanophenoxy) phenoxy ] p ropano ic acid ( D IAC ID ); and 22[42(42carbamoyl222 fluo rophenoxy) phenoxy ] p ropano ic acid (AM IDE). Conversion of the parent compound to its arylöalkylöo r halide derivative fo r determ ination by GC w as found unnecessary. O nly HPLC w as used and under gradient elution all the four compounds separated w ell. Good recoveries w ere obtained w ith the fo rtified so il and w ater samp les. Low pH w as impo rtant fo r the extraction of the four components
Response of gstase and L iver esterase in goldf ish (Ca rra sius aura tus) and topmouth gudegon (Pseudora sboraparva ) after sublethal exposure to cyhalofop-butyl and profur ite-am in ium
(Chinese journal of pesicide science, 2002) ZHU, Guo-nian; Hui ming, WU; Mwalilino, Jilisa K.; Shao-nan, L I
Investigations w ere carried to assess the sublethal effects of a herbicide clincher ( 100 EC) containing cyhalofop2butyl [ 100 g (a. i) ·L - 1 ] as the active ingredient and the insecticide p rofurite2am inium [ 78% SP, 780 g (a. i) ·kg - 1 ] on liver esterases and hepatic glutath ione2S 2transferase (GST ) in go ldfish (Carassius au ratus) and topmouth gudgeon (P seud orasbora p arva). GST w as found to be induced in bo th go ldfish and topmouth gudgeon by the p rofurite2am inium at concentration of 0. 234 m g·L - 1 . Clincher bo th at concentration of 1 and 2 m g·L - 1 caused GST induction in topmouth gudgeon. The m ixture of clincher and p rofurite2am inium had the h ighest effect in topmouth gudgeon 722. 3 nmo l· (m in - 1·m g - 1 p ro tein ) w ith a po ssible indication of additive toxicity. L iver esterases w ere induced by bo th clincher (1 and 2m g·L - 1 ) and p rofurite2am inium (0. 117 and 0. 234m g·L - 1 ) in go ldfish. In topmouth gudgeon liver esterases w ere induced by p rofurite2am inium but inh ibited by clincher. It is suggested that the two bio transfo rm ation enzym es m ay be directly o r indirectly affected by the tested chem icals and that there are differences betw een them
Accessibility and use of nutrition information in addressing under five child malnutrition in Morogoro urban, Tanzania
(Sokoine University of Agriculture, 2002) Chilimo,Wanyenda Leonard
This study was undertaken to examine the access to and use of nutrition information in addressing the problem of malnutrition in Morogoro urban district Tanzania. The study investigated the Maternal and Child Health clinics (MCH) nutrition information delivery systems; variables that determine accessibility and use of information; extent of the use of nutrition information in addressing malnutrition and the relationship between the information that mothers have and the nutritional status of their children. Survey research method was used for data collection whereby questionnaires and face-to-face interviews were used for collecting data. The study found that although the MCH health and nutrition education sessions arc an important aspect in disseminating nutrition information to mothers, these sessions are seldom conducted and the attendance of mothers to these sessions is poor; awareness of mothers concerning different nutritional aspects is still low due to lack of information; and education is the most important variable that determines use and access to nutrition information.
Household waste recovery and recycling: a case study of Kigoma-Ujiji, Tanzania
(Inderscience Enterprises Ltd, 2003) Shams, Shahriar; Ibrahimu, Chikira
Management of waste in most developing countries has become important for most of the cities as they try to curb and control city growth and urbanisation. The general norm where waste management had been the sole duty of municipalities has proved not to work due to lack of funds, public participation, political will and awareness. This paper looks at the general problems faced in household waste recovery and recycling, with a case study from Tanzania. A process scheme that consists of public participation, costs, social acceptance, economic benefits, and hygiene is considered. The overall conclusion is that there is a need for government commitment and general involvement of the public. The setting up of recycling industries will also ease the situation and at the same time create employment for the people.
Influence of bacterial activities on nitrogen uptake rates determined by the application of antibiotics
(Oceanologia, 2003) Tungaraza, Clavery; Brion, Natacha; Rousseau, Véronique; Baeyens, Willy; Goeyens, Leo
The influence of bacterial activities on inorganic nutrients has always affected total phytoplankton uptake rates owing to the absence of a reliable method that can exclude these effects. The use of natural samples to determine the contribution of bacterial activities has been based on the size fractionation method which, unfortunately, is encumbered with uncertainties, especially because of the size overlap between bacteria and phytoplankton communities. In this paper, the results are reported of an estimation of bacterial activities by the use of inhibitors (antibiotics). It was shown that the contribution of bacterial activities to the uptake of nitrogenous nutrients was highest for ammonium (79%), followed by nitrate (72%) and urea (62%). In a second set of experiments the concentration of ammonium was raised by 5 μM. This was done to avoid nutrient limitation resulting from the absence of recycled nutrients following the addition of antibiotics and the maximum contribution of bacterial activity to the uptake rate of ammonium increased to 87%. It can be concluded that the use of inhibitors is a good method, a reliable alternative to the fractionation method. However, it is important to note that inhibitors can affect both phytoplankton growth and the nutrient recycling process. Our results indicate that the application of antibiotics had measurable effects not only on the target bacteria but also on the uptake behaviour of phytoplankton. Our observations were therefore limited to the period when there was no effect on the phytoplankton, as was demonstrated by a carbon protein incorporation experiment.
Management and utilisation of miombo biodiversity: impact of refugees influx in kasulu, Tanzania
(International Master Programme at the Swedish Biodiversity Centre, 2003) Andrew, Woiso Dino
his study was conducted in Kasulu district in Western Tanzania to assess the impact of refugees influx on the management and utilisation of miombo woodland biodiversity. Specifically, the objectives were to (a) assess the uses of and means of using forest resources by refugees and local Tanzanians, (b) compare the extent of impact resulting from harvesting woodland resources between refugees and local inhabitants and to recommend on how the means of utilisation affect sustainability issues of the forest resources. Questionnaire surveys, participant observation and forest inventories were used as tools for data collection. A total of two hundred and forty people were interviewed from two villages and two refugee camps using a pre-tested questionnaire form for the aim of getting baseline data. From each village and camp a nearby forest, which is currently a harvesting site for various Timber and Non-Timber Forest Products (NTFPs) by local Tanzanians or refugees, was used for the inventory. In addition a forest reserve was inventoried as a control site for the other forest areas surveyed. Commonly used tree species were counted and measured for Diameter at Breast Height (DBH). Other notes were made whenever activities such as charcoaling, chalk making, logging and grazing were observed. It was witnessed during participant observation that a huge area of formally miombo woodland and mostly village forest reserves had been converted to settlements and farmlands for refugees. It was found that refugees’ harvesting sites have fewer trees/ha and smaller diameter trees compared to villagers’ forests. The reserve, village and camp forests surveyed had 738, 474 & 351stems/ha. The village forests had a higher species diversity than the other forests at 95% CI (p=0.0008). Pterocarpus angolensis, which is a valuable timber species, was found almost locally depleted with exception of few juveniles found in the village forests. It was deduced from these findings that miombo woodlands in this area are experiencing rapid deforestation due to faster rate of utilisation, hence highlighting possibilities for degrading its biodiversity. Management of these forests, which locally doesn’t have any specific interventional plans and strategies, is facing challenges. The extent of these challenges become complicated since the time for refugees repatriation is not known with certainty. There is a need to assess and redefine present ownership and management patterns and strategies as one of ways to cope with current use pressure and rehabilitate the miombo woodlands in this area. Further studies to compare this influence of massive harvest of miombo resources with places practicing subsistence harvesting of miombo resources are recommended. It is also recommended to carryout population studies for Pterocarus angolensis in Kigoma region to come up with more detailed information about its status for it is highly demanded for furniture despite its threatened status.
Higher order perturbation analysis of plasma and gravitational waves
(Universiteit Antwerpen, 2004) Karugila, Geoffrey Kamahanga
Plateau [1] initiated experimentally and theoretically the stability of a liquid cylinder with surface tension. Lord Rayleigh [2] improved this work and developed the linearized theory for sound waves (although the calculation of sound velocity goes back to Newton and Laplace) and for the Plateau experiments which was then applied to all kinds of fields: gravitation [3. 4, 5], plasma [6], (magneto)hydrodynamics [7, 8, 9], energy principles [10]. The linear theory flourished tremendously in the past century to a large extent due to the goal of fusion. Soon the need for nonlinear theories was manifest e.g. Callebaut [11, 12]. We therefore see in the previous decades a lot of work on nonlinear theory of plasma waves and instabilities being done. These yield either exact solutions or approximate ones. Often exact solutions are obtained after that the equations have been approximated. We may mention the papers with the exact solutions by Malfliet et al. [13, 14, 15], Hereman et al. [16, 17, 18], Verheest et al. [19, 20, 21] on solitary waves and those of Khater et al. on Backlund transformations and Painleve analysis [22, 23, 24, 25]. Amiranashvili et al. [26] gave some exact solutions for standing waves in bounded plasmas without using the solitary wave theory but with some boundary conditions. Callebaut and Tsintsadze [27, 28] e.g., neglecting some higher order terms, dealt with the nonlinear bunching of Alfven waves and the filamentation and modulation of weakly ionized magnetized plasmas. In fact, except for the approaches leading to solitary wave solutions, the nonlinear methods usually yield approximations and usually one has barely an idea how long these are valid in the behavior of the plasma. The approach used in this thesis exploits the Fourier analysis for nonlinear systems. It is rather different from the approaches just mentioned as it allows some insight in the convergence. Moreover, it gives useful results for the many cases where one can not find a closed form for the solitary waves. Indeed the solitary waves are an exceptional and rare case, comparable with a polynomial (as is clear e.g. from Malfliet’s work, see references cited) while the general solution is an infinite series. The polynomial may use a function (e.g. tanh) instead of the (combined) variable itself. Similarly the series may use any function although the customary ones are exponentials and (co)sines. Infinite Fourier series may in principle be considered as an exact solution, but in practice it often is an approximation, which, however, allows clear insight on its validity. The set of (partial differential) equations (e.g. equations (2.1) - (2.4)), together with some initial and/or boundary conditions, defines a set of func tions (which are, of course, interrelated). From the Fourier theory it is known that if a periodic function is continuous from — oo to +oo and has a deriva tive which is piecewise monotonous and continuous, then the function may be developed in a Fourier series which is absolutely and uniformly convergent in any interval. In the thesis we deal with the single variable x (= co t + k • r), which is the combination of the four independent variables i.e. the angular frequency ( cj = 2 tt z /, v = frequency), the time (Z), the wave vector (fc) and space (r). Thus the conditions have to be satisfied for the function(s) of this combined variable. In particular the function should be periodic in co t and in k r. However, an exponential growth is easily accommodated just like the periodic situations as was the case in a hydrodynamical problem [12]. Hence under rather general conditions it is possible to expand the functions defined by the set of equations. When will this breakdown? E.g. when the series diverges, i.e., physically speaking, when instability leading to dis- rupture develops meaning that a (large) amount of energy has been made available (either injected externally or freed by the system itself from e.g. its potential energy or, more generally, from its free energy). The convergence of the series puts conditions on the linear theory, mainly on its amplitude. In fact a linearized theory can never determine its own limitations: that has to be done by the nonlinear analysis. In the previous works [12] it turned out that some experimental situa tions, in particular the oscillations and instabilities of a liquid jet, could be explained very well by this method. Moreover some cases appeared where the nonlinear theory showed that the linear theory was good even up to de struction of the configuration, while for wavelengths much larger than the diameter of the jet the nonlinear terms became dominant. Another breakdown of the method may occur e.g. when the function(s) is (are) not periodic. However, in the linear perturbation theory one works usually with a periodic perturbation and this generates naturally higher order terms which are periodic too as is obvious e.g. in our present work and in the works of Callebaut [12, 29, 30]. For a non-periodic solution one has to take a wholly different start in the linear theory, e.g. by using a series in t and/or re, ?/, 2, or some adequate combination of those, or if nevertheless a periodic or exponential start is used as first order term, to adapt profoundly the nonlinear terms. Such nonlinear approaches have been elaborated in various ways in the literature see e.g. the cited references of Malfliet et al.; Hereman et al.; Verheest et al.; Khater et al.; Callebaut and Tsintsadze.
Therapeutic efficacy of sulfadoxine-pyrimethamine and prevalence of resistance markers in Tanzania prior to revision of malaria treatment policy: Plasmodium falciparum dihydrofolate reductase and dihydropteroate synthase mutations in monitoring in vivo resistance
(The American Society of Tropical Medicine and Hygiene, 2004) Mugittu, Kefas; Ndejembi, Modesta; Malisa, Allen; Lemnge, Martha; Premji, Zulfikar; Mwita, Alex; Nkya, Watoky; Kataraihya, Johannes; Abdulla, Salim; Beck, Hans-Peter; Mshinda, Hassan
Prior to the 2001 malarial treatment policy change in Tanzania, we conducted trials to assess the efficacy of sulfadoxine-pyrimethamine (SP) and the usefulness of molecular markers in monitoring resistance. A total of 383 uncomplicated Plasmodium falciparum malaria patients (between 6 and 59 months old) were treated with SP and their responses were assessed. Mutations in the P. falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes in admission day blood samples were analyzed. Results indicated that 85.6% of the patients showed an adequate clinical response, 9.7% an early treatment failure, and 4.7% a late treatment failure. The quintuple mutant genotype (pfdhfr 51 Ile, 59 Arg, and 108 Asn and pfdhps 437 Gly and 540 Glu) showed an association with treatment outcome (odds ratio 2.1; 95% confidence interval 0.94–4.48, P 0.045). The prevalence of the triple pfdhfr mutant genotype (51 Ile, 59 Arg, and 108 Asn) at a site of high SP resistance (23.6%) was four times higher compared with that observed at sites of moderate SP resistance (6.8−14.4%) (P 0.000001). The genotype failure index calculated by using this marker was invariable (1.96−2.1) at sites with moderate SP resistance, but varied (3.4) at a site of high SP resistance. In conclusion, our clinical and molecular findings suggest that SP may have a short useful therapeutic life in Tanzania; thus, its adoption as an interim first-line antimalarial drug. The findings also point to the potential of the triple pfdhfr mutant genotype as an early warning tool for increasing SP resistance. These data form the baseline SP efficacy and molecular markers profile in Tanzania prior to the policy change.
Effect of E × B drifts in convective zone
(Cambridge University Press, 2004) Callebaut, Dirk K.; Karugila, Geoffrey K.; Makarov, Valentin I.
The E × B drift allows plasma to move through the magnetic field lines and may contribute to various motions inside the Sun (e.g. to explain the adverse gradient of differential rotation in the equatorial zone), at its surface and in the corona. Here we treat an example: using a given azimuthal angular frequency ω(r, θ), rather arbitrary, and the corresponding exact solution for B, we obtain E and the drift velocity. The latter is comparable with the original velocity, but has components in all directions
Reduced variatio around drug-resistant dhfr alleles in African plasmodium falciparum
(Oxford University Press, 2005-05-25) Pearce, Richard J; Malisa, Allen L; Kachur, Patrick; Barnes, Karen; Brian, Sharp; Roper, Cally
We have measured microsatellite diversity at 26 markers around the dhfr gene in pyrimethamine-sensitive and -resistant parasites collected in southeast Africa. Through direct comparison with diversity on sensitive chromosomes we have found significant loss of diversity across a region of 70 kb around the most highly resistant allele which is evidence of a selective sweep attributable to selection through widespread use of pyrimethamine (in combination with sulfadoxine) as treatment for malaria. Retrospective analysis through four years of direct and continuous selection from use of sulfadoxinepyrimethamine as first-line malaria treatment on a Plasmodium falciparum population in KwaZulu Natal, South Africa, has revealed how recombination significantly narrowed the margins of the selective sweep over time. A deterministic model incorporating selection coefficients measured during the same interval indicates that the transition was toward a state of recombination-selection equilibrium. We compared loss of diversity around the same resistance allele in two populations at either extreme of the range of entomological inoculation rates (EIRs), namely, under one infective bite per year in Mpumalanga, South Africa, and more than one per day in southern Tanzania. EIRs determine effective recombination rates and are expected to profoundly influence the dimensions of the selective sweep. Surprisingly, the dimensions were broadly consistent across both populations. We conclude that despite different recombination rates and contrasting drug selection histories in neighboring countries, the region-wide movement of resistant parasites has played a key role in the establishment of resistance in these populations and the dimensions of the selective sweep are dominated by the influence of high initial starting frequencies.
Powerfull nonlinear plasma waves from moderate first order perturbations
(2005-08) Callebaut, D. K.; Karugila, G. K.
The nonlinear Fourier method of Callebaut consists in concentrating on the family of higher order terms of a single Fourier term of the linearized analysis. Thus we have obtained the higher order terms of plasma perturbations, gravitational ones, etc. In the simplest case of cold plasma this resulted in obtaining an analytical expression for the higher order terms. This allowed to investigate the convergence of the series, which in this case limits the first order amplitude to 1/e of the equilibrium density. For the cases without an analytical expression we developed a numerical-graphical method to obtain the convergence limit. Near this limit the total amplitude of the wave becomes very large. The convergence limit decreases with increasing pressure. Thus a wave with moderate first order amplitude may carry a very large energy due to the higher orders. Moreover, this energy is concentrated in a very narrow interval of the phase interval (0, 2π). This may be relevant in many situations. E.g. in the case of ball lightning a tremendous energy may be accumulated while the glowing is still restricted. The triggering of solar flares or coronal mass ejections may thus be caused. Again, when these eruptions reach the Earth the influence of a first order term may be far too small to cause electric power plants to break down; however, the total of all terms may be much more powerful. Cf. March 1989 when the whole state of Quebec, Canada, was a day without electricity due to a solar storm. This is an alternative mechanism from the one proposed by Callebaut and Tsintsadze based on soliton envelope formation, although there the accent was on the heating of the plasma.
On Vladimirov’s approximation for ideal in homogeneous MHD
(2005-08) Callebaut, D. K.; Karugila, G. K.; Khater, A. H.
Vladimirov and Vladimirov and Moffat have considered configurations in ideal magnetohydrodynamics, i.e. inviscid and perfectly conducting. The matter is considered as incompressible. However, the density is allowed to vary slowly. They base the following approximation on this slow variation: they omit the mass density in front of the total derivative of the velocity in the equation of motion. Normally the mass density should appear in front of Du. This is a tremendous simplification which allows them to obtain various interesting results concerning the stability of the configurations. However, in such a kind of approximation the results might be only crude. However, in many applications the results are OK, because crucial in those papers is the vanishing of ∇ρ × ∇φ. Often both gradients are parallel and the results obtained by Vladimirovs approximation are nevertheless valid, e.g. in the application to inhomogeneous gas clouds and protostars. Moreover for small density gradients and/or nearly parallel gradients the approximation is fair. We even suggest an approximation which may be more correct and avoids the term ∇ρ × ∇φ. Hence for linear perturbations and stability analyses the results may turn out to be acceptable. However, for nonlinear stability a more extended analysis is required.
Population change and food availability in Tanzania; a multilevel modeling approach: the case of Ukerewe Islands
(University of Dar es salaam, 2005-08) Malogo, Deogratias Solole
Primary data from a survey of 150- rural households in Ukcrewe district, one of the densely populated rural districts in Tanzania mainland, were used to examine the relationship between socio-demographic variables and household food availability. The study employed the Principal Component Analysis (PCA) in the construction of households’ possession indices which was then used as the proxy determinant of food availability. The 2-level random intercept model with 3-ordered categorical response variable was used in the estimation of coefficient of effects. The findings show that household seasonal migrants, education attainment by household members, farm land resources and life cycle of household at different stage of development that was measured by the age of household head, were significant. It was further noted that seasonal migrants and farm land were likely to reduce the odds ratio of a household of being extremely poor or poor. An increase of a person with secondary or post-secondary education in a household reduced the odds ratio of a household of being extremely poor by 52.8 percent as compared to 19 percent odds ratio reduction by increase of non educated household member. The findings show that the young aged head of household was 3 and 5 times less likely to be extremely poor as compared to old and middle age headed household respectively. The data could not allow any viable conclusion to be drawn from variables such as; household sex ratio, sex of household head, size of the household and proportion of household permanent migrants because they were statistically insignificant
Comparison of two models in the estimation of nitrogen uptake rates using data from 15-N incubation experiments
(nstitute of Oceanology PAS, 2005-08-16) Tungaraza, Clavery; Brion, Natacha; Baeyens, Willy
This paper compares two uptake rate models, Dugdale & Goering’s (D&G) model and Elskens’ model. The aim is to provide an insight into how estimates of uptake processes, i.e. regeneration and loss rates from both dissolved and particulate nitrogen pools, influence the total uptake rates when the two models are compared. The uptake rates of three nitrogenous nutrients (nitrate, ammonium and urea) from 15-N incubation experimental data were compared. The comparison indicated that the D&G model underestimated nitrate uptake rates by about 34%, implying a significant regeneration and loss rates of the nutrient. Elskens’ model further showed that the loss rates from the dissolved phase were about 40% and 25% for the ammonium and urea pools, respectively, indicating that the D&G model underestimated the experimental uptake rates of the nutrients. On average, nitrification made up about 30% of the total ammonium uptake flux, whereas the sinks from particulate nitrogen and dissolved nitrogen were estimated at 36% and 56%, respectively. The D&G model sometimes overestimated the f -ratio values to about 60% and higher as a result of ammonium and urea uptake rates underestimation. This paper also shows that detritus adsorption, bacterial uptake and cell lysis are equally important processes.
Using free and open source software for e-Learning system (FOSES) in Tanzania
(2006-02) Lwoga, Tandi Edda; Sanga, Camillius; Kazwala, R.R; Mganilwa, Z.M
The implementation of e-Learning software in Tanzania’s universities as well as other developing countries is still very low even though there are plenty Free and Open Source Software (FOSS) that can cater for this purpose. Among ten universities, only the University of Dar Es Salaam (UDSM) has managed to implement the e-Learning software in Tanzania by using WEBCT and Blackboard are e-Learning proprietary software. This study therefore discusses how the Tanzania Universities can establish and implement the e-learning technology with a case study of the Sokoine University of Agriculture. Specifically, this study describes the early evaluation steps that were observed during the adoption of the e-learning platform at SUA. The extensive literature review, experience gained from other universities, and the analysis of the available open source e-learning software were used for the selection and further improvement of the e-learning platform at SUA. Challenges that are delaying the implementation of e-learning platform at SUA are also discussed, and recommendations are given upon them. It is anticipated that the findings of the study will be used by all stakeholders in planning cost-effective and efficient ICTs implementations for general improvement of education sector from national level up to district level.
Dhfr and dhps mutations in plasmodium falciparum isolates in Mlandizi, Kibaha, Tanzania: association with clinical outcome
(Tanzania Health Research Bulletin, 2006-05) Kidima, W; Nkwengulila, G.; Premji, Z.; Malisa, A.; Mshinda, H
Sulfadoxine-pyrimethamine (SP), the current first line antimalarial drug in Tanzania, is compromised by evolution and spread of mutations in the parasite's dhfr and dhps genes. In the present study we established the baseline frequencies of Plasmodium falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) mutant genotypes and their potential for predicting the in vivo efficacy of SP in Mlandizi, Tanzania. The efficacy of SP treatment was by following 116 children with uncomplicated falciparum malaria for 14 days after treatment. Infected blood samples were collected on filter paper at days 0, 3, 7 and 14. Parasite genomic DNA was extracted and point mutations at positions 51, 59, 108 and 164 of the dhfr gene and at 581, 540 and 437 of the dhps gene were analysed by nested Polymerase Chain Reaction/ Restriction Fragment Length Polymorphism. Out of 116 children enrolled, 98 (86%) of eligible children demonstrated an adequate clinical response by day 14. There were 7.3 % early and 6.7% late therapeutic failures. At day 0, only 8.0% (4/50) the parasites showed no mutation at the dhfr locus; for dhps this was 73%. Triple mutant dhfr alleles (Ile 51, Arg 59, Asn 108) occurred in 47%, double mutant dhps (Gly 437, Glu 540) alleles in 7.9%. No mutation was detected at codon 164 of the dhfr gene. The presence of triple dhfr mutant alleles was related to clinical failure, but did not show significant association (Fisher exact test, P=0.166, OR 2.15 0.776.20). The higher rates of mutation on the dhfr do not spell a bright future for SP treatment in Tanzania. It is rational to think of an alternative first line antimalarial drug, while retaining SP for malaria intermittent treatment in pregnancy.

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