African Journals Online

JOURNAL OF THE GHANA SCIENCE ASSOCIATION

VOLUME 2 No. 1 – 2000

Alternative assessment as an ingredient of continuous assessment in Junior Secondary Schools

M.K. Amedeker

Department of Science Education

University College of Education of Winneba

ABSTRACT

Modes of testing in schools at all levels of the educational system have come under scrutiny in recent times. Testing in science has its peculiarities. Science teachers, therefore, have to be well informed about operations of any new examination systems adopted for national education curriculum. This study was a field research conducted in the Junior Secondary Schools in the Winneba Educational District. The main objectives were to: find out the types of assessment used by teachers; assess the problems faced by science teachers in organising the continuous assessment; evaluate the effectiveness of the implementation process. In order to gather data, a conceptual framework known as the "Effectiveness of Implementation" was developed based on: Logistic arrangement, Implementation, Philosophy of continuous assessment, Outcomes of assessment and Pupils' participation. A set of closed and structured questionnaire was developed for science teachers. An interview schedule was also developed for the science teachers. The results, were analysed by assigning weightings on a three-point Likert scale to the items in the questionnaires. It was found out that whilst science teachers appeared to have understood the philosophy of the continuous assessment, they hardly transferred their knowledge into practice. Pupils' participation was, therefore, adversely affected. One recommendation made is that educational policy makers need to set up structures to monitor the performance of the continuous assessment in science. There is the threat that the basic schools may cede the assessment of their pupils to an external examining body for a one-shot examination.

Ubiquitin expression in coeliac disease

¹F.A. Yeboah and ²D. White

¹Department of Molecular Medicine, School of Medical Sciences,

Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.

²Department of Health Sciences, Queens Medical Centre,

University of Nottingham, University Boulevard, NG7 2UR, Nottingham, UK.

ABSTRACT

Biopsy-sections of the small intestine of established coeliac patients were investigated by immunoperoxidase procedures, using monoclonal antibodies to detect the presence of ubiquitin, a heat shock protein, to find out the role, if any, of this protein in the pathogenesis of coeliac disease. Sections from each case stained with haematoxylin and eosin were available for assessment of mucosal morphology. The epithelial cells of the small intestine appeared to stain relatively more for ubiquitin compared to non-coeliac patients. From these observations, we suggest the following: ubiquitin, a stress response protein, seems to play a role either in the pathogenesis or pathophysiology of coeliac disease, an inappropriate stress response involving this protein within the mucosa itself may be crucial as an initiating event in the architectural derangement of the mucosal damage associated with coeliac disease; ubiquitin acts probably as a cross-reacting antigen in the work up to the mucosal damage possibly via a local autoimmune process involving the activation of helper T cells against alpha-gliadin in coeliac patients; ubiquitin expression may be associated with cell death or autophagy during mucosal atrophy in coeliac disease.

Electrolyte monitoring in the management of essential hypertension

M.T. Agyei-Frempong, R.A. Ngala, E.F. Laing, W.K.B.A Owiredu, and F.A.Yeboah

Department of Molecular Medicine, School of Medical Sciences

Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.

ABSTRACT

Serum levels of sodium and potassium were estimated by flame atomic emission spectroscopy and calcium spectrophotometrically by using o-cresolpthalein complexone reaction in 140 newly-diagnosed in-patients with essential hypertension both before and after treatment. Eighty normotensives matched for age and gender were used as controls. In this study it was observed that there was only a slight correlation between the plasma sodium and calcium levels and diastolic pressure with no statistically significant difference between hypertensives and the control group. There was an inverse correlation between potassium levels and blood pressure (r = -0.023). There was a positive correlation between the plasma sodium levels and elevated blood pressures (r = 0.32). This is in conformity with the observation that high levels of potassium are associated with reduced blood pressure .The study, therefore, suggests that whilst potassium monitoring may be necessary in hypertensive management, therapeutic altering of plasma sodium and calcium levels as a means of managing essential hypertension may not be necessary.

Aspects of the reproductive biology of the red pandora, Pagellus bellottii (Pisces: Sparidae) in Ghana

A. Asabere-Ameyaw

Department of Science Education, University College of Education of Winneba, Winneba.

ABSTRACT

The reproductive biology of Pagellus bellottii (Stenidachner, 1882) occurring in Ghana is reported in this paper. Data was collected on monthly samples taken from November 1993 to October 1995. Specimens longer than 18.9 cm TL were predominantly males, but the ratio of males to females was not significantly different in small fishes. Overall, the males were numerically dominant. The smallest mature male and female fish measured 13.6 cm TL, and 13.5cm TL, respectively. These sizes correspond to maturity age of 0.65 yr. The length at which 50% of the fish are matured was estimated at 21.0 and 20.0cm TL which corresponded to 1.5 and 1.3 yr, respectively, for males and females. Changes in the gonadosomatic index (GSI) suggested a minor spawning activity in January and February, and a major spawning from June to September. Spawning in the species, therefore, occurred during the upwelling seasons in Ghanaian waters. The occurrence of two distinct groups of ova representing mature and immature stocks indicated possible discontinuous breeding in the species.

The distribution of Podostemaceae in Ghana

Gabriel K. Ameka

Department of Botany, University of Ghana, P.O. Box LG 55, Legon.

ABSTRACT

The distribution of five species of Podostemaceae, namely, Ledermanniella bowlingii, Polypleurum submersum, Saxicolella agumatsa, Saxicolella amicorum and Tristicha trifaria occurring in Ghana has been described. T. trifaria is widespread in the country. The other Podostemaceae species are at present known from one, two or three rivers. S. agumatsa was found on the cliff surface of the Wli falls on the Agumatsa river. L. bowlingii and P. submersum were found in two rivers, namely, Asuboni river, near Kwahu Nteso and Akrum river, near Begoro. S. amicorum occurred in three rivers in different geographical areas: in Ankasa river in the Ankasa Resource Reserve, in the Kakum river near Asuansi and in Nwhini river, near Aduabrim. All the five species occurred in the wet semi-equatorial climate type. T. trifaria is known from the dry equatorial and tropical continental climate types. S. amicorum and T. trifaria were found in the semi-equatorial climate type. T. trifaria occurs in both low and high rainfall areas, from areas with less than 1000 mm to areas above 1900 mm of rainfall y-1. The other species are confined to higher annual rainfall areas of 1250 to above 1900 mm. In Ghana Podostemaceae were found to occur on older rocks of the Precambrian and Palaeozoic eras, and not on rocks of recent origin. They occur between 75–900 m above sea level.

Neutron activation analysis for some toxic elements in the hair of some “galamsée” workers in Ghana

K. Ahmad¹, E.K. Osae ², B.J.B. Nyarko², Y. Serfor-Armah¹

¹Chemistry Department, ²Physics Department

Ghana Atomic Energy Commission, P.O. Box 80, Legon.

ABSTRACT

Hair samples of 26 workers involved in small scale gold mining, popularly called “Galamsée,” have been analysed using thermal NAA for mercury and other elements including As and Sb, all considered as toxic. The following elements have been found in these hair samples Hg. As, Sb, Sm, Ho, Zn, La, Na, K, Au and Br. Similarly, hair analysis of 10 non-galamsée workers, for control and comparison, using the same NAA technique yielded the following elements: Ho, Zn, Na, K and Br.

A theoretical model for predicting neutron fluxes for cyclic Neutron Activation Analysis

¹E.H.K. Akaho, ¹ B.T. Maakuu, ²B.J.B. Nyarko, ²E.K. Osae,

³Y. Serfor-Armah, ⁴A. Chatt

¹Department of Nuclear Engineering & Mat. Sc., ² Department of Physics, ³Department of Chemistry National Nuclear Research Institute, Ghana Atomic Energy Commission,

P.O. Box LG80, Legon-Accra, Ghana.

⁴Trace Analysis Research Centre, Department of Chemistry, Dalhouise University, Halifax, Nova Scotia, B3H, 4JI, Canada.

ABSTRACT

A theoretical model has been developed for prediction of thermal neutron fluxes required for cyclic irradiations of a sample to obtain the same activity previously used for the detection of any radionuclide of interest. The model is suitable for radiotracer production or for long-lived neutron activation products where the background activities have half-lives ten times less than the activity of the radionuclide of interest. For selected irradiation conditions of timing of the repeated and single irradiation, the calculated results of thermal fluxes for various cycles and periods are discussed in the paper.

Determination of some wear elements in used car engine oil and oil filter paper using Neutron Activation Analysis

¹ P.S. Adu, ¹E.H.K. Akaho, ² B.J.B. Nyarko, ³ Y. Serfor- Armah

Ghana Research Reactor -1 Centre, National Nuclear Research Institute, P.O.Box 80, Legon.

¹ Nuclear Engineering Department; ² Physics Department; ³ Chemistry Department

ABSTRACT

In the present investigation, wear elements in used car engine oil and in oil filter paper were determined using instrumental neutron activation analysis (INAA). The objective was to identify an effective and scientific method of monitoring car engine health. Results obtained from analysing blank and used samples of engine oil and of filter paper showed the presence of Al, Mn, Sb, V, and Zn, in both samples .The relatively higher concentration of some wear elements in the oil filter paper as compared to that of the used engine oil seem to suggest that used oil filter paper analysis using INAA is more effective in following wear trends than used engine oil analysis and could be adopted as scientific technique in monitoring car engine health in Ghana. However, this method does not present a drawback to the used engine oil analysis as in the case of aircraft engines. Used engine oil analysis using INAA still remains an effective, simple and scientific technique for determining wear in car engines.

The influence of Si(Li) detector characteristics on the accuracy in X-ray analysis using the QXAS package

F.G. Ofosu, S. Akoto Bamford and I.J.K. Aboh

Physics Dept., National Nuclear Research Institute, G.A.E.C.

P.O. Box 80, Legon, Accra, Ghana.

ABSTRACT

A study has been carried out to show how variations in Si(Li) detector characteristics affect the accuracy of X-ray spectra evaluation. The detector characteristics investigated are Be window thickness, Au layer, Si dead layer and Si Detector Sensitive volume. For each of the detector parameters, different thickness values including the manufacturer's specified values were chosen to calculate detector efficiency using the spectra obtained from Cr₂O₃, Co, Cu, Zn and As standards. An IAEA-sponsored package, “Quantitative X-ray Analysis Software (QXAS)” was used for the work. An inverse variation of efficiency values with thickness in the Be window, Au layer and Si Dead layer was realised. The Gold layer was found to have the most significant effect, followed by the Si Detector Dead Layer with the Be Window having least significant effect. The Detector sensitive volume showed no observed effect.

An empirical function for the full energy peak efficiency for a P-type co-axial high purity germanium detector

E.K. Osae

Neutron Activation Analysis Laboratory, Department of Physics, National Nuclear Research Institute, Ghana Atomic Energy Commission., P.O. Box 80, Legon, Accra.

ABSTRACT

An empirical analytical function has been obtained for the full energy peak efficiency of a co-axial P-type High Purity Germanium Detector for gamma-ray energies in the range of 80 - 1333 keV and source-to-detector distance in the range of 1.0 - 4.0 cm. Comparison of the calculated efficiencies with the corresponding experimental value agrees very well within standard deviations of 1.8 - 3.7 %.

Characterization of gums from local acacia species for the food and pharmaceutical uses

K. Frimpong-Mensah

Institute of Renewable Natural Resources,

Kwame Nkrumah University of Science and Technology, Kumasi

ABSTRACT

Gums are widely used to support the pharmaceutical, brewery, food, cosmetics and adhesive industries. Their uses are mainly based on their physicochemical properties and their mucilage. These properties make them act as emulsifiers, suspenders, thickeners, stabilizers, binders, and lubricants. In spite of the tremendous quantities of gums used in industries in Ghana, the chemistry of the locally available gums are not known. The main commercial gums used in industry are from the Acacia senegal, an exotic species. Chemical properties of gums from selected Acacia species - A. Acacia polyacantha, A. sieberiana, and A. dudgeoni were studied. The local gums had acceptable levels of moisture content (which is not more than 15%), less than 1.0% insoluble matter, less than 5% total ash value, and acid insoluble ash. They dissolved in water and sodium hydroxide, but not in most organic solvent. They showed levorotary optical rotation in water, and maintained a relative stable pH with time. The gums did not contain any starch or tannins. It was confirmed from the sugar reactions that their sugar composition were Rhamnose, Arabinose, Galactose, and Glucuronic acid. The viscosities increased with concentration and decreased with time, rose with pH till a pH of about 5 and then fell as the pH increased from 6 to 14. The local gums can be used as suitable substitutes for the commercially imported ones.

Determination of the stereochemistry of 4-chromenecarbaldehydes using Nuclear Overhauser Enhancements (NOE)

R.K. Akuamoah

Department of Chemistry, University of Ghana, Legon

ABSTRACT

The paper reports studies on the use of 4-chromenecarbaldehydes as suitable substrates for the assessment of the accuracy of interpretations of Nuclear Overhauser Enhancements (NOE) data for chromenecarbaldehydes and related compounds, such as the 3,4-dibromochromanones. The investigative protocol that has been used consists of the comparison of NOE data from experiment with those obtained from theoretical considerations based on computational molecular modelling, using PCMODEL. The theoretical conditions that have been considered were two-fold: the chromenecarbaldehydes were considered as either static/planar molecules or as dynamic and puckered structures in which the carbonyl moieties have, at least, torsional vibration. This approach has been found to be a valid one and the dynamic consideration was found to give calculated NOE values close to NOE data obtained from experiment. It is thus believed that a combination of molecular modelling and such computations could be a powerful tool in the elucidation of conformational information from NOE measurements. It has also been shown, from our experiments and theoretical considerations, that in order to avoid an over-simplistic use of NOE data for the detailed assignment of conformational equilibra and diastereoisomerism, one must ensure that enhancements from the same experiments are considered.

Combination of malted cereals and cassava starch in the production of sugar syrup

T.K. Hammond and G.S. Ayernor

Department of Nutrition and Food Science

University of Ghana, P.O. Box LG 134, Legon

ABSTRACT

The relative capacity of malted cereals and their optimum conditions of temperature and pH in the hydrolysis of starch were studied. Malted cereals prepared from rice, maize, sorghum and millet were used to degrade cassava starch to produce sugar syrup. Effect of pH and temperature on the level of dextrose equivalent produced indicated that the combination of malted maize, rice and sorghum with cassava starch at pH 5 in 0.015M citrate buffer and pH 5.5 for malted millet produced relatively high amounts of sugar at temperatures of 60^oC for malted maize, millet and sorghum and 55^oC for malted rice. The combination of malted rice and cassava starch produced the highest amount of sugar syrup among the various cereals studied.

Isozyme polymorphisms in eight accessions of sorghum (Sorghum bicolor L. Moench)

E.Y. Danquah, E.T. Blay, W.M. Osae and Y. Alifo

Department of Crop Science, University of Ghana, P.O. Box LG 44, Legon, Ghana.

ABSTRACT

Eight accessions of sorghum, collected from the gene bank of the Savanna Agricultural Research Institute (SARI) were characterised using their isozyme banding patterns. Crude protein extracts from the leaves of seven-day old seedlings were subjected to starch gel electrophoresis. The gels were stained to reveal the banding patterns of four isozymes: acid phosphatase, esterase, peroxidase and malate dehydrogenase. Esterase exposed seven banding patterns whereas peroxidase, acid phosphatse, and malate dehydrogenase exposed five, three and two banding patterns, respectively. None of the enzymes alone could be used to separate all of the accessions. Combining the isozyme data, it was possible to unambiguously distinguish all of the accessions. Similarity values indicated that most of the accessions are closely related.

Response of two promiscuous soybean (Glycine max (L.) Merrill) genotypes to Bradyrhizobial inoculation in two Ghanaian soils

F.K. Kumaga and K. Etu-Bonde

Crop Science Department, Faculty of Agriculture, University of Ghana, Legon.

ABSTRACT

Three strains of Bradyrhizobium spp (LS8, LS50 and TAL 102) were evaluated in two soils in Ghana (Agawtaw and Bawjiasi series) for their effects on nodulation and growth of two promiscuously nodulating soybean varieties (TGX 536-02D and TGX 306-036C). The experiment was carried out in a plastic house at the Crop Science Department of the University of Ghana, Legon. Inoculation increased nodule number, nodule dry weight, N yield and shoot dry weight of plants. The magnitude of these inoculation responses was influenced by soil type and soybean variety. Responses were higher in the Bawjiasi soil than in the Agawtaw soil and also higher for variety TGX 536-02D than for TGX 306-036C. Strain TAL 102 induced the highest nodulation, nitrogen accumulation and shoot growth. These results indicate the possibility of increasing nodulation, N₂ fixation and yield of field grown promiscuous soybean through inoculation with selected strains of Bradyrhizobium spp.

A survey of raw processing methods for kolanuts

Mercy Asamoah, K. Osei-Bonsu and Osei Sarkodie

Cocoa Research Institute of Ghana (CRIG), P.O. Box 8, Tafo-Akim

ABSTRACT

A survey was carried out in the Eastern and Ashanti Regions of Ghana to identify indigenous methods for the raw processing and handling of kolanuts. Using purposive and accidental sampling techniques and interviews, thirty-two individuals and eleven focus group discussions were undertaken at fourteen and ten towns/locations in the Eastern and Ashanti Regions, respectively, in 1997. Kolanuts were processed either by pre-soaking and washing or by underground fermentation and stored for 3 to 12 months before export or selling. Women are generally engaged in kolanut processing but storage and marketing appear to be the preserve of the men. Storage materials used were commonly baskets and sacks with lining leaves. Although local preservatives such as wood ash, dried ground pepper, sliced lime and leaves of Jatropha were used in some areas of Ashanti to control storage insects, by far the commonest insect control agents in the two regions were chemicals which are dangerous to human health. Some of these chemicals are Gastoxin (Aluminium phosphide) which is locally called `bomb', Gammalin 20 and Veneno poison all of which go with their attendant health hazards of which the kola dealers were apparently ignorant and/or adamant. The need to evolve alternative safe chemical storage treatments and to intensify studies on local substitutes such as wood ash, pepper and lime is therefore advocated.

Production and consumer acceptability of soymilk-based yoghurt

A.O. Danquah, R. Amamoo and T. Wayo

Department of Home Science, University of Ghana, Legon.

ABSTRACT

Although milk products are very nutritious, they are expensive and thus hardly affordable by many people in developing countries, such as Ghana. This study, therefore, attempted to substitute soymilk for cow milk in the production of yoghurt that could be accepted and inexpensive to consumers. Soymilk was extracted from soybeans after blanching, dehulling and blending. This was flavoured and mixed with reconstituted full cream at various proportions : (i) 50 % soymilk and 50 % full cream (Sample A); (ii) 25 % soymilk and 75 % full cream (Sample B); (iii) 75 % soymilk and 25 % full cream (Sample C); (iv) 100 % full cream (Sample D). These mixtures were used to prepare yoghurt which were evaluated by a 52-member panel known to consume yoghurt on regular basis. The sensory characteristics were evaluated using the 9-point Hedonic scale where 1 denoted “disliked extreme” and 9 “liked extremely”. Fan yoghurt, from Fan Milk (Sample E), served as control. Analysis of Variance (ANOVA) was used to determine significant differences at 5 % level of significance in terms of likeness of the products. Each of the samples received a mean score above 5 which was the minimum score. The results indicated that there was no significant difference between the samples and that the panelists liked all the samples. However, some samples were liked more than others. Sample B was the most preferred variety of the soymilk-based yoghurt. Soymilk can, therefore, be used together with cow milk to produce acceptable and affordable yoghurt since soybean is cheaper in the market and soymilk production is simple.

The development of value-added demersal Fishery Commodity In Ghana – The Challenges Of The Future

¹Francis Osei and ²Kwame A. Koranteng

¹Agricultural Development Bank, P.O. Box 4191, Accra.

²Marine Fisheries Research Division, P.O. Box BT-62, Tema

ABSTRACT

The important role of the fisheries sub-sector to Ghana's export development cannot be over-emphasised. Demersal fish species attract reasonably high prices on the international market, especially when value is added to the landed product. This paper reviews the demersal fishery resource of Ghana as an export commodity, and discusses the economic implications of value-addition for Ghana. It also identifies some challenges the industry is likely to be confronted with in the near future, and proposes strategies to effectively manage these challenges.