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Articles 961 - 990 of 1029
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Influence Of Endocrine Activity On Larval Development In Busseola Fusca (Fuller) (Lepidoptera:Noctudine), M Njau
Tanzania Journal of Science
The present study investigated the role of juvenile and moulting hormones in development of Busseola fusca. Morphometric measurements were used to distinguish differences in endocrine activity between non-diapause and diapause development with regard to the prothoracic glands and the corpora allata. The corpora allata of non-diapause larvae were similar in size to those of diapause larvae. The critical period for the prothoracic glands to produce the required titer of ecdysone for further development was by the third day after ecdysis to the last larval instar. Juvenile hormone extracts from haemolymph of Busseola fusca larvae in non-diapause and diapause development had …
Subsidence History Of The Rukwa Rift In South West Tanzania Analysed From Ivuna Well, E I Mbede
Subsidence History Of The Rukwa Rift In South West Tanzania Analysed From Ivuna Well, E I Mbede
Tanzania Journal of Science
The variation in subsidence rate during rift basin development is a good indication for the Geodynamic history of a sedimentary basin. The sedimentary section of Ivuna Well is herein used to explain the structural evolution of Rukwa Basin within the Western Rift of the East African Rift System. The sedimentary record of Ivuna Well is extracted from published information. The effects of sedimentary load, corrected for compaction and variation in water depth, and lake-level have been removed to obtain the "tectonic subsidence." Curves show two phases of accelerated subsidence related to the fault controlled rifting phases: The Karoo rifting and …
D13c Signatures Of Flora, Macrofauna And Sediment Of A Mangrove Forest Partly Affected By Sewage Wastes, J F Machiwa
D13c Signatures Of Flora, Macrofauna And Sediment Of A Mangrove Forest Partly Affected By Sewage Wastes, J F Machiwa
Tanzania Journal of Science
Stable carbon isotope ratios (d13C) of sediments, suspended particulate matter, and crab gut content from Maruhubi mangrove forest, Zanzibar, were determined. Stable carbon isotope ratios were used to determine sources of organic matter in the forest. Mangrove organic carbon (d13C±SD = - 27.97±0.25) was found to be an important component of the sediment organic matter except at the marine fringe zone (d13C±SD = - 17.26±0.83). The areal distribution of d13C values show that the marine fringe zone was rich in organic carbon of marine origin. The terrestrial fringe zone was dominated by a mixed source of sediment organic carbon (d13C±SD …
Preliminary Evidence For A Second -525-545 Ma Old Event Of Granilate Facies Metamorphism In The Mozambique Belt Of Tanzania And Its Implication For A Two-Stage Model For Gondwana Assembly, M A H Maboko
Tanzania Journal of Science
Garnets from two samples of the Kitumbi granulites in the Mozambique Belt of north eastern Tanzania yield Sm-Nd ages of 525±15 Ma and 545±15 Ma. At the 95% confidence level, these ages are younger than the 576 ±15 to 634±16 Ma (Mean 606±12 Ma) ages previously reported from the more extensive Eastern Granulites. The Kitumbi garnets are therefore interpreted as dating cooling from a granulite facies event that is distinctly younger than the 630-700 Ma event that produced the Eastern Granulites. Unlike the Eastern Granulites, the Kitumbi rocks occur as small enclaves not separated from the surrounding amphibolite facies gneisses …
Heavy Metals And Organic Pollutants In Sediments Of Dar Es Salaam Harbour Prior To Dredging In 1999, J F Machiwa
Heavy Metals And Organic Pollutants In Sediments Of Dar Es Salaam Harbour Prior To Dredging In 1999, J F Machiwa
Tanzania Journal of Science
Heavy metals and organic contaminants were analysed in the sediments of the inner area of the Dar es Salaam harbour. Complementary analytical parameters, such as, the organic carbon content and the silt/clay fraction of the sediments showed good positive correlation (r = 0.64). Stations that had high content of fine grain material in the sediment also indicated relatively high level of organic carbon and pollutants. The Florida criteria (MacDonald 1993) for assessment of pollution of tropical marine sediments was adopted in oredr to evaluate the extent of pollution in Dar es Salaam harbour sediments. The Florida criteria is one of …
Thermogravimetric Study Of Gadolinium Chlorotungstate In Air Between 25 And 1500°C., F N Ngassapa, N U Venskovskii
Thermogravimetric Study Of Gadolinium Chlorotungstate In Air Between 25 And 1500°C., F N Ngassapa, N U Venskovskii
Tanzania Journal of Science
Using DTA, X-ray powder diffraction, chemical and optical methods, the thermostability of Gd3WO6Cl3 was investigated. The compound was relatively stable on heating in air up to 710oC. Above this temperature it exhibited two decomposition temperature ranges (710-900oC and 900-1130oC). The final product consisted of a mixture of gadolinium tungstate of different composition. This suggests the decomposition scheme of polyphase products
Macrominerals In The Milk Of Healthy And Mastitic Cows, I E. Mohamed, O A. Olowni, F I. Habbani, G E. Mohamed
Macrominerals In The Milk Of Healthy And Mastitic Cows, I E. Mohamed, O A. Olowni, F I. Habbani, G E. Mohamed
Tanzania Journal of Science
Concentration values were obtained using X-ray fluorescence (XRF) technique for chlorine, potassium and calcium levels in milk-from subclinical and clinical mastitis-infected COWS. Concentration values for sodium were determined using atomic absorption spectroscopy. Comparisons were made with healthy cow's milk. Subclinical mastitic milk had significantly higher levels of sodium and chlorine and significantly lower levels of potassium and calcium than the milk from healthy cows. Comparison between clinical mastitic milk revealed a significant increase in sodium and chlorine levels for clinical mastitic milk, while levels of potassium showed a non-significant change and calcium levels decreased significantly.
Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo
Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo
Tanzania Journal of Science
Time series data of currents and sea current levels recorded by current meter and tide gauges, respectively from Chwaka Bay, Zanzibar were obtained from the entrance near to Mapopwe Creek and at the middle of the bay. The analysis of the data reveals that the tidal currents had an asymmetry near the entrance to Mapopwe Creek where the ebb currents were stronger than flood currents although the ebb periods were considerably longer than flood periods.
Stable Isotope Compositions Of Sedimentary Organic Matter Off Zanzibar Town, Ann Muzuka
Stable Isotope Compositions Of Sedimentary Organic Matter Off Zanzibar Town, Ann Muzuka
Tanzania Journal of Science
Stable isotope compositions of sedimentary organic carbon for sediments collected off the Zanzibar Town averaged -17.9%. Low isotope values of organic carbon, which were associated with high C/N ratios, were observed within Zanzibar harbour suggesting a significant contribution of terrestrial organic matter to the harbour. Sediments collected outside the Zanzibar harbour were richer in 13C than those collected within the harbour area. This 13 enrichment in 13C can be attributed to a decrease in the influence of terrestrial organic matter (0M) and high contribution of' sea grasses. A decrease in the influence of terrestrial OM is further supported …
A Simple Method For Indexing Powder Diffraction Patterns Of Cubic Materials (11): Using The D-Values Of Reference, Me Kamwaya
Tanzania Journal of Science
From the d-values (in decreasing order) taken from powder diffraction patterns of the cubic material a variable constant, KQ, which is a multiple of Ʃh12 where Q = l/d2 can be determined. The smallest values of Q give rise to multiples of ones, twos and threes, which correspond to the smallest values of Ʃh12 for the primitive, bcc, and fcc/diamond Type structures, respectively. Cognance of the lattice types is best accomplished by the ΔQ-criterion, where ΔQ denotes the difference between successive values of Q. Indexing is greatly simplified and the use of rigorous tables is …
Bis(4-Carboxylato-5-Methyl-Oxazolidine) Nickel(Ii)Dihydrate, Its Preparation And Crystal Structure, Me Kamwaya
Bis(4-Carboxylato-5-Methyl-Oxazolidine) Nickel(Ii)Dihydrate, Its Preparation And Crystal Structure, Me Kamwaya
Tanzania Journal of Science
An aqueous solution of nickel (Il) acetate tetrahydrate was added to warm solution of L-threonine and sodium bicarbonate. The mixture was subsequently treated with aqueous solution of formaldehyde and stirred until the blue solution turned green. The reaction consists in a base catalysed condensation of formaldehyde with L-threonine-nickel (Il) – complex followed by formation of an oxazolidine ring. A single crystal X-ray investigation was carried out at 120(1) oC. The X-ray structure analysis showed an octahedral nickel comp/ex containing two water molecules. The oxazolidine rings were connected to the Ni by nitrogen and one of the carboxylato oxygen atoms. …
Heavy Metal Content In Water Hyacinth (Eichhornia Crassipes (Mart) Solms.) From Lake Victoria Shore, Tanzania, Nk Mohammed, In Makundi
Heavy Metal Content In Water Hyacinth (Eichhornia Crassipes (Mart) Solms.) From Lake Victoria Shore, Tanzania, Nk Mohammed, In Makundi
Tanzania Journal of Science
Water hyacinth (Eichhornia crassipes (Mart) Solms,) samples from Lake Victoria shore were analysed for heavy metal pollution using Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF). The roots of the water hyacinth samples were collected from areas influenced by industrial and domestic sewage and little influenced area. Water hyacinth from industrial area and those from sewage discharge points had higher concentrations of heavy metals than that from the little disturbed area.
Comparison Of Synchronization Strategies For Systems Employing Multiple-Code Markers, Hn Kundaeli
Comparison Of Synchronization Strategies For Systems Employing Multiple-Code Markers, Hn Kundaeli
Tanzania Journal of Science
Frame synchronization strategies based on single-code markers have been widely researched and reported. On the other hand, frame synchronization strategies based on multiple-code markers have not been so well reported although they have become quite popular in systems operating at high transmission rates. In this paper, the performance of various synchronization strategies for systems employing multiple-code markers is compared. It is shown that, systems employing contiguous multiple-code markers have better performance than those employing distributed multiple-code markers. It is also shown that, systems in which the individual codewords of the markers are checked during loss of synchronization hare better performance …
Facies Analysis Of Limestones At Songo Songo Island In South East Tanzania, S Kapilima, Ka Msindai
Facies Analysis Of Limestones At Songo Songo Island In South East Tanzania, S Kapilima, Ka Msindai
Tanzania Journal of Science
Songo Songo Island is situated at close proximity of the continental slope of the coastal sedimentary basin of Tanzania. Its rich varieties of marine organisms and carbonate sediments provide a classic example of island emergence with the development of successive detrital and organic reefs as well as lime sand. Facies analysis at the Island was done through mapping, logging, faces and microfacies analysis. Results show that Songo Songo Island can be classified into three faces; the detrital reefs, organic reef and lime sand. The fossil assemblage reveals that most of the fauna and flora are frame-building organisms in organic reef. …
Turbulent Heat Energy Exchange In A Tropical Bay, S B. Mahongo
Turbulent Heat Energy Exchange In A Tropical Bay, S B. Mahongo
Tanzania Journal of Science
Atmospheric and Sea surface temperature data were used to describe the magnitude of turbulent heat energy processes Chwaka Bay, Zanzibar, Bulk aerodynamic formulae were applied in the investigation for data collected over a 23-day period in 1996. These were those Smith (1988), Friehe and Schmitt (1976), Mohanty and Mohan Kumar (1990) and Bunker (1976). The computed fluxes of moisture were 156 Wm-2 (Smith), 158 Wm-2 (Friehe and Schmitt), 160 Wm-2 (Mohanty and Mohan Kumar) and 188 Wm-2 (Bunker), respectively. The corresponding fluxes of sensible heat were 15 Wm-2, 13 Wm-2, 18 Wm …
Status Of Heavy Metals Pollution In The Nile Around Khartoum Area, F I. Habbani, S E. Salih
Status Of Heavy Metals Pollution In The Nile Around Khartoum Area, F I. Habbani, S E. Salih
Tanzania Journal of Science
Investigations for heavy metals pollution in the Nile around Khartoum area were carried Out using the technique of x-ray fluorescence (XRF). Samples were collected from various locations around Khartoum area before and after the flood. The results indicated that there was no heavy metals pollution in the Nile in Khartoum area resulting from industrial activities. The origin for the observed heavy metals concentrations, except for Pb, was considered to be soil erosion caused by the river on its journey from the Ethiopian Highlands and Lake Victoria. However, there are indications that some Pb pollution could be due to emissions of …
Synthesis Of Bis-(3-Carbethoxy-6-Methoxy-4-Methyl-2-Quinolyl) Selenide, Rr Malisa, G L. Mhehe, Sjm Mdachi
Synthesis Of Bis-(3-Carbethoxy-6-Methoxy-4-Methyl-2-Quinolyl) Selenide, Rr Malisa, G L. Mhehe, Sjm Mdachi
Tanzania Journal of Science
In the execution of a synthetic strategy aiming at 3-acetyl-2,4-dichloro-6-methoxyquinoline, a precursor to a 4-methoyselenolo[2,3-b]quinolone, we have instead obtained 2-chloro-3-carbethoxy-6-methoxy-4-methylquinoline. These results strongly suggest that the compound claimed to be 3-acetyl-2,4-dihydroxy-6-methoxyquinoline in the literature and a precursor to 3-actyl-2,4-dichloro-6-methoxyquinoline, is 3-carbethoxy-2-hydroxy-6-methoxy-4-methylquinoline, a precursor to 2-chlo-3-carbethoy-6-methoxy-4-methylquinoline. The reaction of the latter compound with sodium hydrogen selenide in ethanol yielded bis-(3-carbethoxy-6-methoxy-4-methyl-2-quinolyl) selenide.
Analysis Of The Analytic Hierarchy Process Methodologies, C B Alphonce, C M. Brugha
Analysis Of The Analytic Hierarchy Process Methodologies, C B Alphonce, C M. Brugha
Tanzania Journal of Science
We review various methodologies for estimating the impact scores of alternatives on criteria within the Analytic Hierarchy Process (AHP). The results show that the geometric mean method for retrieving impact scores from judgment matrices and the weighted geometric mean aggregation rule provide a best fit to the underlying structure of the problem.
A Universal Space Group Code In The Natural Science, M E Kamwaya
A Universal Space Group Code In The Natural Science, M E Kamwaya
Tanzania Journal of Science
A more systematic and universal cell-edge rule is proposed, in which the criterion in the determination of space groups (except for the cubic and trigonal systems) should be a ˃ b ˃ c. This leads to having two setting in the tetragonal and hexagonal systems, while in the monoclinic a third setting is added based on when angle a ≠ 90o.
On Intamolecular Hydrogen Bonding Of O- Hydroxyaromatic Schef Bases And Related Molectules: Structre Of N-P- Chlorobenzylidene -2- Hydroxyaniline, Me Kamwaya
Tanzania Journal of Science
C13H10NOCl, Mr = 231.682, F(000) = 480, Z = 4, Dc = 1.387, Dm = 1.385 mgm-3, V = 1109. 53A, is monoclinic, space group P21/n with a = 13.033(4), b = 5.869(7), = 14.77 (4) A, and ß = 78.9(2)0. Least squares refinement led to a final R-value of 0.0539 for 520 reflexions. The presence of a five-membered intramolecular hydrogen bond in N-p-chlorobenzylidene-2-hydroxyaniline is established.
Cultivating The Edible Oyster Mushroom Pleurotus On Sawdust, Fss Magingo
Cultivating The Edible Oyster Mushroom Pleurotus On Sawdust, Fss Magingo
Tanzania Journal of Science
The edible mushroom Pleurotus pulmonarius was grown on pasteurized saw dust supplemented with either Crotalaria ochroleuca (N2- fixing legume) or with chicken manure. Inoculated, unsupplemented sawdust acted as control. Sawdust supplemented with C. ochroleuca biomass yielded the highest fresh weight of the mushroom with a biological efficiency (B.E) of 83%. Sawdust supplemented with chicken manure had a 67% B.E., while control gave the least harvest (B.E. = 32%). Reasons for the differences are discussed.
Heavy Metal Pollution In Lake Victoria, J. W. A. Kandoro, M. H. Mikidadi
Heavy Metal Pollution In Lake Victoria, J. W. A. Kandoro, M. H. Mikidadi
Tanzania Journal of Science
This work presents the Energy dispersive x-ray flouorences (EDXRF) analysis of water and plant samplesfrom Lake Victoria at Mwanza for heavy metal pollution. Water and plant (Water hyacinth) samples were collected from Lake Victoria around Mwanza municipality from twenty seven locations. There were varying elemental concentrations from different locations reflecting the activities carried out in the vicinity of the lake. Maximum concentration values of up to 1640 mg/L for Pb, 23.3 mg/L for Mn, 42.8 mg/L for Cr, 15.1mg/L for Pb, 23.3mg/L for Cu, and 742.5 mg/L for Zn, were observed. Possible sources of the elements are discussed, from which …
A Person Computer Programme For Fitting Of Moessbauer Spectra, J. W. A. Kandoro
A Person Computer Programme For Fitting Of Moessbauer Spectra, J. W. A. Kandoro
Tanzania Journal of Science
A Computer code for fitting spectra obtained in Moessbauer spectroscopy on a personal computer is described. The code is designed around a least-squares routine which fits the characteristics peaks in a Moessbauer spectrum with Lorentzian shaped peaks and the background of a spectrum with a polynomial function. The least squares routing is based on the Newton-Raphson algorithm. The method is implemented in a computer program written in quick basic for which prove that the program in quick basic for IBM compatible personal computer. Tests are described which prove that the program is able to provide reliable values for the parameters.
Bottom Reflection In A Shallow Tidal Bay, S B. Mahongo
Bottom Reflection In A Shallow Tidal Bay, S B. Mahongo
Tanzania Journal of Science
Bottom reflection of short-wave radiation was investigated using measurements taken from a platform in a shallow tidal lagoon on the eastern coast of Zanzibar, the Chwaka bay. Measurements were taken from 18 January to 9 February, 1996. The investigation was facilitated using a simple model of shallow water reflectance. The presumption that bottom reflection plays a significant role in the heat budget of the bay has been found to be incorrect. The computed mean value of the flux due to bottom reflection during this period was only of the order of 2Wm-2, and it is unlikely that variations …
Global Warming: A Threat To Human Societies And Natural Ecosystems, Yunus D. Mgaya
Global Warming: A Threat To Human Societies And Natural Ecosystems, Yunus D. Mgaya
Tanzania Journal of Science
The possible influences of increases of mean sea surface temperatures are briefly reviewed. It is virtually certain that human activities are changing the composition and behavior of the atmosphere, leading to increased concentrations of greenhouse gases. Recent analyses and model predations show that risks to human societies and natural ecosystems from enhanced greenhouse effect may be large. A rising sea level could result in quite dramatic changes in maritime boundaries (as states to act to protect their maritime zones. It is concluded that in setting management goals with respect to mitigating the effects of global warming, one needs to recognize …
Evidence For A Shore-Normal Energy Gradient And Its Character In The Speiekeroog Back Barrier Tidal Flats, German North Sea Coast, N Nyandwi
Tanzania Journal of Science
Sediment distribution in the Spiekeroog backbarrier tidal flats has been studied with the aim of identifying the factors controlling their deposition. Form the mainland coast northwards three physiographic units are recognizable namely, the tidal flats adjacent to the coast, the tidal channels with the intervening flats and the dunes and tidal flats adjoining Spiekeroog island. The areal distribution of the sand fraction (˂4.0 phi) shows a shore normal energy gradient with increasing energy towards the sea. Very fine sands are found very close to the mainland coast, fine to very fine in the central part and fine sand on the …
Effect Of Filter Pore Size For Liquid Effluent Removal On The Performance Of An Artificial Rumen Reactor, Amelia Kajumulo Kivaisi, Martin Barugahare
Effect Of Filter Pore Size For Liquid Effluent Removal On The Performance Of An Artificial Rumen Reactor, Amelia Kajumulo Kivaisi, Martin Barugahare
Tanzania Journal of Science
The effect of filter pore size on performance of an artificial rumen reactor was studied. Filter units of pore sizes in the range of 10-300 mm were used in the reactor to separate the solids from the fermentation liquid at solid and liquid retention times of 72 and 12 h, respectively. The overall performance of the reactor decrease markedly with increasing filter pore size. Total cellulose activity and substrate degradation decreased by 70 and 30% respectively, when the pre sizes changed from 10 to 300 mm. ciliate protozoa decreased in number with increasing filter pore size and were almost completely …
Characterization Of Iron Sulfides Form Lake Victoria Gold Field, Jwa Kondoro, Ca Kiwanga
Characterization Of Iron Sulfides Form Lake Victoria Gold Field, Jwa Kondoro, Ca Kiwanga
Tanzania Journal of Science
Iron sulphides form the Lake Victoria gold field have been characterized using Mossbauer spectroscopy. Thirteen iron sulphide samples have been categorized into four groups depending on which of the following phases is dominant: monoclinic pyrrhotite, hexagonal pyrrhotite, pyrite or non sulphide phases. A discussion on the characterization of the different phases is given in the paper
Dispersion Of Heavy Metals Along Msimbazi River Basin In Dar Es Salaam, Jwa Kondoro
Dispersion Of Heavy Metals Along Msimbazi River Basin In Dar Es Salaam, Jwa Kondoro
Tanzania Journal of Science
Several locations of Msimbazi River, a prominent river basin passing through the urban area of Dar es Salaam into the Indian Ocean were sampled for about six months. The sampled specimens of water and sediments were investigated for the extent of heavy metal pollution using atomic Absorption Spectrophotometry (AAS) and X-Ray Fluorescence analysis (XRF) techniques. The major elements of interest in this study were Pb, Cd, Zn, Cu and Cr. Water analysis showed low concentrations for most of the elements. However, sediments showed significant concentration level in various stretches of the river basin for certain elements. The report analyses distribution …
Application Of Multivariate Analysis In The Exploration For Tin In Granites: A Study Of Granites From Northwestern Tanzania Using Discriminant Function And Factor Analysis, J.R. Ikingura
Tanzania Journal of Science
Variations in major and trace element Composition of granites from Karagwe-Ankolean (NE Kibaran) belt in northwestern Tanzania have been investigated by factor analysis and discriminant function statistical methods, The variations are attributed to three main factors. Factor 1 is positively loaded with CaO, MgO, Fe2O3 (Fe total), TiO2, MnO, Ba, Sr, Zr and Y, and negatively loaded with P2O5, SiO2, B and Rb. Factor 2 is positively loaded with Na2O, P2O5 Mno, Sn, Li, Rb and Y, and negatively loaded with TiO2, K2 …