383 research outputs found
Sort by
Assessing the Impact of Increasing Antimicrobial Resistance of Vibrio cholerae on the Future Trends of Cholera Epidemic
No full textThis is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.Cholera, an acute intestinal infection caused by the bacterium Vibrio cholerae, remains a major public health problem in many
parts of Africa, Asia, and Latin America. A mathematical model is developed, to assess the impact of increasing antimicrobial
resistance of Vibrio cholerae on the future trends of the cholera epidemic. Equilibrium states of the model are determined and their
stabilities have been examined. The impacts of increasing antimicrobial resistance of Vibrio cholerae on the future trends of cholera
epidemic have been investigated through the reproductive number. Numerical results are provided to support analytical findings
The SAFEX-JIBAR Market Models
No full textThis article is published on Journal of Mathematical Finance Vol. 2, pp.321-326 in 2012. It is about the construction of the SAFEX-JIBAR model which gives prices consistent with both economic practicality and with other Black-type models.It is possible to construct an arbitrage-free interest rate model in which the LIBOR rates follow a log-normal process
leading to Black-type pricing formulae for caps and floors. The key to their approach is to start directly with modeling
observed market rates, LIBOR rates in this case, instead of instantaneous spot rates or forward rates. This model is
known as the LIBOR Market Model. We formulate the SAFEX-JIBAR market model based on the fact that the forward
JIBAR rates follow a log-normal process. Formulae of the Black-type are deduced
Chemical composition, in vitro dry matter digestibility and in vitro gas production of five woody species browsed by Matebele goats (Capra hircus L) in a semi-arid savanna, Zimbabwe.
No full textThe chemical composition, in vitro dry matter digestibility (IVDMD) and in vitro gas production (IVGP) of five woody species: Commiphora pyracanthoides, Terminalia prunioides, Acacia tortilis, Faidherbia albida and Dichrostachys cinerea browsed by Matebele goats in an open semi-arid savanna was determined at three leaf phenophases. T. prunioides had the highest IVGP volume (80.1ml) and C. pyracanthoides the highest IVDMD (0.60) with D. cinerea having both the lowest IVDMD (0.39) and IVGP volume (43.7ml). This was presumably due to the high condensed tannins (CT) in D. cinerea (20.1 A550nm) as compared to the low CT in T. prunioides (1.2 A550nm) and C. pyracanthoides (2.9 A550nm). T. prunioides had lower acid (240.6 vs. 354.4g/kg DM) and neutral (351.2 vs. 430.5g/kg DM) detergent fibre than C. pyracanthoides. Crude protein (CP) and IVDMD declined while neutral detergent fibre (NDF) and acid detergent fibre (ADF) increased with leaf maturity. In vitro dry matter digestibility was not influenced by CP (r=0.09, P>0.05) and NDF (r=?0.29, P>0.05) while ADF negatively affected IVGP (r=?0.54, P<0.05). Gas production was positively associated with IVDMD (r=0.54, P<0.05). Condensed tannins had a greater negative effect on IVDMD (r=?0.58, P<0.05) and IVGP (?0.68, P<0.01) than acid (r=?0.46, P>0.05; r=?0.54, P<0.05) and neutral (r=?0.29, P>0.05; r=?0.51, P>0.05) detergent fibre. Total phenolics were positively correlated to IVGP (r=0.73, P>0.05). We conclude that T. prunioides had good rumen fermentation attributes due to low NDF, ADF and CT contents
Use of the Value Stream Mapping tool for Waste Reduction In Manufacturing. Case Study for Bread Manufacturing In Zimbabwe.
No full textProceedings of the 2011 International Conference on Industrial Engineering and Operations Management
Kuala Lumpur, Malaysia, January 22 ? 24, 2011Value Stream Mapping (VSM) is a World Class Manufacturing tool that can be used to minimise waste in manufacturing. Companies are experiencing intense competitive pressure due to globalisation hence they cannot afford to operate with waste in their processes. This paper details the use of the VSM tool in reducing waste in bread
manufacturing for a company in Zimbabwe. The case study shows how the VSM tool was used to identify and reduce defects by 20%, unnecessary inventory by 18% and motion by 37%. It incorporates waste relationship
ranking and the importance of management commitment in waste reduction
Impact of Maternal Effects on Ranking of Animal Models In Genetic Parameter Estimation For 18-Months Weight In Indigenous Tuli Cattle of Zimbabwe
No full textMaternal effects have been reported using different animal models for post weaning
growth traits in some cattle breeds. Variance components for additive direct, additive maternal,permanent environmental maternal effects, the covariance between additive direct and maternal effects
were estimated by restricted maximum likelihood, fitting five animal models from 2978 of 18 months(18MW) weight pedigree records of indigenous Tuli cattle of Zimbabwe. All investigated models
included a random direct genetic effect, but different combinations of random maternal genetic and permanent environmental effects as well as for direct-maternal genetic covariance. The direct heritability
(h2a) were constant (0.10) when the maternal genetic effects were included in the model, while (h2a)estimates were higher (0.22) and (0.63) when maternal effects were excluded. The maternal heritability(h2m) was (0.23) and higher than the direct heritability (0.10) when only maternal genetic effects were included in the model and did not change even when the permanent environmental effects of the dam was added. The permanent environmental effects of the dam was negligible and a strong positive correlation
between direct and maternal genetic effects (?2am) was observed. The strong positive genetic correlation between direct and maternal genetic effects would not limit the effective utilization of both direct and
maternal effects in selection for 18MW growth in indigenous Tuli cattle. A simple animal model with additive direct genetic effects as the only random effect would be appropriate for genetic evaluation of
18MW in indigenous Tuli cattle.
Analysis of acrylamide in traditional foodstuffs in Zimbabwe
No full textFull Length Research Paper. Available online at http://www.academicjournals.org/AJFSWe carried out a preliminary study on the occurrence of acrylamide in potentially high risk traditional foodstuffs consumed in Zimbabwe. Various studies have shown that acrylamide, a ?probable human carcinogen?, is formed by high temperature thermal processing of carbohydrate rich foodstuffs (lnternational Agency for Research on Cancer, 1994). Acrylamide concentrations in roasted maize, groundnuts, soy beans and boiled maize were determined using liquid chromatography tandem mass spectrometer (LC-MS/MS). The relative standard deviation of the analytical technique was 5% and the limit of detection was 0.02 ?g/kg. Acrylamide was not detected in boiled maize. Roasted maize contained 450 ?g/kg acrylamide. Roasted groundnuts had 140 ?g/kg and finally, roasted soybeans with a concentration of 70 ?g/kg acrylamide.Department of Applied Chemistry, National University of Science and Technology,Zimbabwe and Er DevCo Consultants AB, J?rneklev Kapellbacken, SE-53393 K?llby, Sweden
Effect of shoot morphology on browse selection by free ranging goats in a semi-arid savanna
No full textWoody plants protect themselves against loss of valuable nutrients and photosynthetic tissue
to herbivores. Plant anti-herbivory defences influence their selection by browsers. Woody plant
species which produce new leaves on old lignified branches (shoot-limited, SL) (e.g., Terminalia
prunioides and Commiphora pyracanthoides) have different anti-herbivory mechanisms to those
that produce new leaves on new growing shoots (shoot-dominated, SD) (e.g., Grewia tenax,
Grewia monticola and Colophospermum mopane). Shoots and leaves of SD species are more
exposed to herbivores than SL species requiring better chemical defences in the form of
high fibre and condensed tannins (CT) (proanthocyanidins) contents. We studied selection
patterns of Matebele goats browsing on T. prunioides and C. pyracanthoides (SL species)
and G. tenax, G. monticola and C. mopane (SD species) in an open savanna during the plant
growth season (November to May). Browse selection was then related to crude protein
(CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), condensed tannins (CT),
total phenolics (TP), in vitro gas production (IVGP) and in vitro dry matter digestibility
(IVDMD). The two SL species (T. prunioides and C. pyracanthoides) had higher browse selection
indices (BSI) (1.96 vs 0.37) than the three SD species (G. monticola, G. tenax and C. mopane). The
SD species had higher NDF (553.25 vs 410.95 g/kg DM), ADF (353.53 vs 238.49 g/kg DM) and CT
(15.87 vs 0.43 g/kg DM) than SL species. The SL species had higher IVGP after 48 h (68.99 vs
33.00 ml/300 mg DM) and IVDMD (0.54 vs 0.43) than SD species. T. prunioides was the
most fermentable and C. pyracanthoides the most digestible while C. mopane had the lowest
IVGP and IVDMD. Browse selection indices had inverse relationships with NDF (r=?0.92,
Pb0.01), ADF (r=?0.91, Pb0.01) and CT (r=?0.87, Pb0.01) and positive relationships
with IVGP (r=0.97, Pb0.01) and IVDMD (r=0.68, Pb0.05). We conclude that SL species
had higher BSI than SD species due to their lower contents of CT, NDF and ADF and higher
digestibility and rumen fermentation. The higher NDF, ADF and CT in SD species were an
anti-herbivory defence strategy
Impact of Vaccination and Culling on Controlling Foot and Mouth Disease: A Mathematical Modelling Approach
No full textPublished Online November 2011 (http://www.SciRP.org/journal/wjv)Foot and mouth disease (FMD) is a major threat, not only to countries whose economies rely on agricultural exports, but also to industrialized countries that maintain a healthy domestic livestock industry by eliminating major infectious diseases from their livestock populations. In this paper a simple mathematical model is formulated and comprehen- sively analyzed to assess the impact of vaccination and culling on controlling FMD. Overally the study demonstrates that vaccination and culling are essential on controlling FMD if they are all implemented. Furthermore the study illus- trates that culling latently infected (early detection of infected animals) is extremely important on controlling FMD dy- namics
Spin-density-wave behaviour of the (Cr100-xAlx)95Mo5 alloy system
No full textProceedings of South African Institute of Physics (SAIP), 2011. The 56th annual conference of the South African Institute of PhysicsElectrical resistivity, Seebeck coefficient and specific heat measurements on a
(Cr100-xAlx)95Mo5, 0 8.1 at.% Al alloy system are reported. The results indicate two
possible quantum critical points in the magnetic phase diagram of this system. One is an
incommensurate spin-density-wave ? paramagnetic quantum critical point situated at
1.5 at.% Al and the other a paramagnetic ? commensurate spin-density-wave critical point
at 5 at.% Al. We forward experimental evidence that this system harbours two
spin-density-wave related quantum critical points which presents an unusually rich case study
for magnetic quantum criticality of the itinerant kind.South African National Research Foundatio
Magnetic behaviour of the Cr-Al alloy system around the triple point
No full textProceedings of the South African Institute of Physics (SAIP) 2011. The 56th annual conference of the South African Institute of PhysicsElectrical resistivity and specific heat measurements on a series of Cr1-xAlx (0 ? x ?
0.034) alloy single crystals are reported. The results indicate that the triple point, where the
incommensurate and commensurate spin-density-wave phases coexist with the paramagnetic
phase, is situated close to T = 0 K on the magnetic phase diagram