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Metal Accumulation and Antioxidant Enzyme Activity in C. gariepinus, Catfish, and O. mossambicus, Tilapia, Collected from Lower Mguza and Wright Dams, Zimbabwe.
No full textThe aim of this study was to measure antioxidant
enzyme activities as biological indicators of pollution in
tissues of two species of fish. Five Clarius gariepinus and
three Oreochromis mossambicus were collected from Umguza
Dam (polluted dam) whilst seven C. gariepinus and
eight O. mossambicus were collected from Wright Dam
(relatively pristine dam). Diphosphotriphoshodiaphorase
and catalase activities were consistently lower (42 ? 2%
and 78 ? 20%, respectively) in liver whilst malondialdehyde
levels were two times higher in muscles of both species
of fish collected from Umguza Dam. However, seleniumdependent
glutathione peroxidase (Se-GPX) activity was
elevated four-fold in liver and gills of O. mossambicus collected
from Umguza Dam. Metal levels were two to five
times higher in muscles of both species of fish collected from
Umguza Dam. Fish from Umguza Dam seem to have
responded to pollution by increasing Se-GPX specific
activity in an effort to detoxify peroxides produced as a result
of metal induced oxidative stress
Metal accumulation and antioxidant enzyme activity in C. gariepinus, Catfish, and O. mossambicus, Tilapia, collected from lower Mguza and Wright dams, Zimbabwe
No full textThe aim of this study was to measure antioxidant
enzyme activities as biological indicators of pollution in
tissues of two species of fish. Five Clarius gariepinus and
three Oreochromis mossambicus were collected from Umguza
Dam (polluted dam) whilst seven C. gariepinus and
eight O. mossambicus were collected from Wright Dam
(relatively pristine dam). Diphosphotriphoshodiaphorase
and catalase activities were consistently lower (42 ? 2%
and 78 ? 20%, respectively) in liver whilst malondialdehyde
levels were two times higher in muscles of both species
of fish collected from Umguza Dam. However, seleniumdependent
glutathione peroxidase (Se-GPX) activity was
elevated four-fold in liver and gills of O. mossambicus collected
from Umguza Dam. Metal levels were two to five
times higher in muscles of both species of fish collected from
Umguza Dam. Fish from Umguza Dam seem to have
responded to pollution by increasing Se-GPX specific
activity in an effort to detoxify peroxides produced as a result
of metal induced oxidative stress
Using wind energy for harvesting and providing sustainable safe groundwater for a Rural Community in the Masendu Ward in Zimbabwe.
No full textProceedings of the 3rd International Conference on Appropriate Technology, Kigali, Rwanda (2008).Masendu Ward is a Rural Community in Zimbabwe that covers nearly 42 km2 with a
population of approximately 16500. It lies in a semi - arid region with a low average
seasonal rainfall of 493mm (Meteorological Dept, 2006). This results in a general water
shortage for domestic and agricultural use. Unavailability of a reliable source of water
is a cause for concern and has weakened the community to cope with development needs.
This problem is exacerbated by the emigration of young people to neighboring countries in search of employment. The very young and very old are left to fetch water from available sources which are far away. This project and paper looks at water abstraction methods and develops the use of windmill energy far water pumping. The main aim is to supply sufficient water to the Masendu Community. This would be achieved by focusing on establishing suitable sites for borehole drilling, designing, manufacturing and installing windmill pumping systems as well as the envisaged reticulation. This paper also highlights community involvement and empowerment. It is an experimental
intervention study that results in water available availability; community development
and engagement in commercial activities such as market gardening and brick molding. Time will be saved for the community to do other value adding. A windmill is a machine that converts wind energy to usable energy through the rotation of a wheel made up of
adjustable blades. It is an environmentally friendly way of pumping water which has
been used for a long time. It does not require human power and uses wind a renewable
source of energy. The project team designed and constructed a windmill for identified
boreholes in the Masendu ward. Results pertaining to the improvement of windmill
efficiency are an ongoing issue
Indigenous Design and Production Entrepreneurship: Sector Performance Audits and Proactive Support
No full textPublished in Lonaka, Bulletin of the Centre for Academic Development, March 2008,
University of BotswanaThere is little doubt, if at all, that one of the most urgent goals for developing Africa
is genuine economic emancipation, which would, in turn, expedite solutions to the
persistent problems of poverty, disease, ignorance, civil strife, and many others. This
emancipation requires deliberate, proactive home-grown initiatives that gradually
unshackle economically deprived nations from dependence on imported expertise,
ideas, tools and products, to a culture of planned local design, production and trade in
globally competitive wares and products. Such a mindset has evolved over the years
in industrialised countries through steady and cumulative growth from small to
medium to large-scale business enterprises. In this paper we propose a systematic
audit for small and medium-scale enterprises in the design and production business
which would assist to identify the necessary support needed to propel the local small
and medium-scale sector into national and global competitiveness
The Student Factor in building an e-learning culture: Experiences at the University of Botswana
No full textProceedings of the 3rd International Conference on e-Learning University of Cape Town, South Africa 26-27 June 2008This paper presents findings of a small study on the prevailing characteristics and preferences of university students that can be linked to their motivation to adopt and sustain e-learning as their key learning strategy. The qualitative case study was carried out through a questionnaire survey, interviews and classroom observations of third year students enrolled in a five-year degree programme in design and technology at the University of Botswana. The university has embarked on a deliberate path of technological transformation through the University of Botswana e-learning initiative (UBel) which has been significantly supported by the institution?s management (Thurab-Nkhosi et al 2005). In this study, students were taken through a variety of learning activities incorporating internet-searches, group work and peer presentations, media-enhanced lectures, and guest lecturing. Through these activities, the students were encouraged to discover and communicate their strengths and preferred learning styles in an attempt to inform their readiness and motivation to embark on full-scale e-learning as desired by UBel.
Owing to various reasons, the bottom-up approach to organizational transformation and innovation diffusion is often less explored because of, among others, problems of feasibility and expediency. The largely imported e-learning technology is often assumed transferable and appropriate for all students, regardless of background, orientation and aspirations
Mnqgwayi: a stick throwing game of the Kalanga people of Zimbabwe.
No full textThis paper describes an indigenous game, mngqwayi, a stick throwing game of the
Kalanga people of Zimbabwe. Participation in traditional indigenous games by communities improves their quality of life by supporting self-determined sports, games
and cultural activities, which encourages equal access to participation in the social
and cultural fabric of the communities.
Data was collected from a population of the Kalanga people of Zimbabwe. Focus Group
Discussions, individual interviews, demonstrations, observations, visual recordings and audio recordings assisted in capturing of physical skills, techniques and game patterns.
Players, mostly boys, played the game in summer on grasslands and riverbanks, used
long slender sticks blunt at one end and aerodynamically sharpened at the other end,
with the object of having the stick icochet, slide on the ground or traject off the
ground for some distance. Competence is premised on power, skill and technique, from
which, mngqwayi can be classified as a game of physical skill. The physical and cultural appeal of this game makes it ideal for sportification and institutionalization
New Curved Spacetime Dirac Equation-On the Anomalous Gyromagnetic Ratio.
No full textI propose three new curved spacetime versions of the Dirac Equation. These
equations have been developed mainly to try and account in a natural way for the observed
anomalous gyromagnetic ratio of Fermions. The derived equations suggest that particles
including the Electron which is thought to be a point particle do have a finite spatial size
which is the reason for the observed anomalous gyromagnetic ratio. A serendipitous result
of the theory, is that, two of the equation exhibits an asymmetry in their positive and
negative energy solutions the first suggestion of which is clear that a solution to the problem
as to why the Electron and Muon ? despite their acute similarities - exhibit an asymmetry
in their mass is possible. The Mourn is often thought as an Electron in a higher energy
state. Another of the consequences of three equations emanating from the asymmetric
serendipity of the energy solutions of two of these equations, is that, an explanation as to
why Leptons exhibit a three stage mass hierarchy is possible
The Twin Paradox Revisited and Reformulated-On the Possibility of Detecting Absolute Motion
No full textThe famous twin paradox of the Special Theory of Relativity by Einstein
(1905) is revisited and revised. This paradox is not a paradox in the true sense of a paradox
but a reflection of a misunderstanding of the problem and the Principle of Relativity. The
currently accepted solution to this takes into account the accelerations and deceleration
of the traveling twin thus introducing an asymmetry that solves the paradox. We argue
here that, with the acceleration and deceleration neglected, the problem is asymmetric
hence leading to the same conclusion that the traveling twin will age less than the stay at
home. We introduce a symmetric twin paradox whose solution can not be found within the
currently accepted provinces of the STR if one adopts the currently accepted philosophy
of the STR namely that it is impossible for an inertial observer to determine their state of
motion. To resolve this, we present (in our modest view) a simple and convincing argument
that leads us to conclude that it must be possible for an inertial observer to determine their
own state of motion. With this, we are able to solve the symmetric twin paradox. The fact
that it is possible for an inertial observer to determine their state of motion ? brings us back
to the long rejected idea of an all pervading and permeating medium ? the Aether, namely
the Lorentz luminiferous Aether. An experiment capable of validating or invalidating this
claim is suggested.North-West University -Potchefstroom Campus, School of Physics - Unit for Space Research
Modelling the immmunopathogenesis of HIV-1 infection and the effect of multidrug therapy: the role of fusion inhibitors in HAART
No full textThe role of fusion inhibitors in HAARTThere is currently tremendous e?ort being directed at developing
potent, highly active antiretroviral therapies that can e?ectively control HIV-
1 infection without the need for continuous, lifelong use of these drugs. In
the ongoing search for powerful antiretroviral agents that can a?ect sustained
control for HIV infection, mathematical models can help in assessing both the
correlates of protective immunity and the clinical role of a given drug regimen as
well as in understanding the e?cacy of drug therapies administered at di?erent
stages of the disease. In this study, we develop a new mathematical model of
the immuno-pathogenesis of HIV-1 infection, which we use to assess virological
responses to both intracellular and extracellular antiretroviral drugs. We ?rst
develop a basic mathematical model of the immuno-pathogenesis of HIV-1
infection that incorporates three distinct stages in the infection cycle of HIV-1:
entry of HIV-1 into the cytoplasm of CD4+ T cells, transcription of HIV-1
RNA to DNA within CD4+ T cells, and production of HIV-1 viral particles
within CD4+ T cells. Then we extend the basic model to incorporate the e?ect
of three major categories of anti-HIV-1 drugs: fusion/entry inhibitors (FIs),
reverse transcriptase inhibitors (RTIs), and protease inhibitors (PIs). Model
analysis establishes that the actual drug e?cacy of FIs, ? and of PIs, ? is
the same as their e?ective e?cacies while the e?ective drug e?cacy for the
RTIs, r?, is dependent on the rate of transcription of the HIV-1 RNA to DNA,
and the lifespan of infected CD4+ T cells where virions have only entered the
cytoplasm and that this e?ective e?cacy is less than the actual e?cacy, ?. Our
studies suggest that, of the three anti-HIV drug categories (FIs, RTIs, and
PIs), any drug combination of two drugs that includes RTIs is the weakest in
the control of HIV-1 infection
Determining Effective Spraying Periods to Control Malaria via Indoor Residual Spraying in Sub-Saharan Africa.
No full textResearch ArticleIndoor residual spraying?spraying insecticide inside houses to kill mosquitoes?is an important method for controlling malaria vectors in sub-Saharan Africa. We propose a mathematical model for both regular and non-fixed spraying, using impulsive differential equations. First, we
determine the stability properties of the nonimpulsive system. Next, we derive minimal effective spraying intervals and the degree of spraying effectiveness required to control mosquitoes when spraying occurs at regular intervals. If spraying is not fixed, then we determine the ?next best?
spraying times.We also consider the effects of climate change on the prevalence of mosquitoes.We show that both regular and nonfixed spraying will result in a significant reduction in the overall
number of mosquitoes, aswell as the number of malaria cases in humans.We thus recommend that the use of indoor spraying be re-examined for widespread application in malaria-endemic areas