Showing papers in "Scientific Research and Essays in 2009"

Understanding benefits and risks of pesticide use

Abstract: Pesticides are widely used in most areas of crop production to minimize infestations by pests and thus protect crops from potential yield losses and reduction of product quality. Thus, they play an essential role in ensuring high profits to farmers, providing reliable supplies of agricultural produce at prices which are affordable to consumers, and also improving the quality of produce in terms of cosmetic appeal which is also important to buyers. Benefits from pesticide use can accrue to a number of different recipients, not only to farmers or consumers, but also to the society. At the same time, there is evidence of both direct and indirect dangers involved in the use of these chemical substances both for humans and the environment. Although discussions among scientists and the public have repeatedly focused on the real, predicted, and perceived risks that pesticides pose to people and the environment, in reality nobody will ever know with complete certainty that a pesticide is safe or not. Thus, a major issue which always arises is whether we are willing to accept the risks of pesticide use in pursuit of the benefits. It is necessary to reduce unreasonable fears, heighten awareness, foster support, and steer good public policy on pesticides and their use. The most promising opportunity for maximizing benefits and minimizing risks is to invest time, money, and effort into developing a diverse toolbox of pest control strategies that include safe products and practices that integrate chemical approaches into an overall and ecologically based framework which will optimize sustainable production, environmental quality, and human health. Key words: Pesticides, crop protection, pest control, human health, risk communication.

The role of science and technology education at network age population for sustainable development of Bangladesh through human resource advancement

Abstract: Education is supposed to play a vital role for the development of a nation. Many countries made progression through education. Nevertheless, some of them also failed to retain the development achieved since these countries failed to supply required skilled workforce for emerging economics caused by globalization and rapid change of economic pattern. This now forces policymakers to prioritize the production of skilled manpower that can contribute for sustainable development. The countries that achieved sustainable development have given a high priority to science and technology education in formulating education policy. Bangladesh has no more alternatives in order to gain development, except properly utilizing its population. Bangladesh’s economy and human development could have grown faster than its actual progression in the last 25 years (that is, since independence in 1971), if it had earlier taken substantial steps in educational development. This paper has defined a ‘network age population’ for Bangladesh. This paper also suggests that this population is required to provide science and technology based education with some revision of education policy in order to ensure the sustainable development. Key words: Employment market, network age, societal dependency, technological transformation, Technology Achievement Index (TAI), workforce development.

The effects of guided inquiry instruction incorporating a cooperative learning approach on university students' achievement of acid and bases concepts and attitude toward guided inquiry instruction

Abstract: The purpose of this study was to investigate the effects of guided inquiry instruction incorporating with cooperative learning environment on University students’ achievement of acid and bases concepts and attitude toward guided inquiry instruction. The subject of this study consisted of 55 first year University students from two intact classes of a Chemistry Course instructed by the same teacher. One of the classes was randomly assigned as the experimental group and the other was assigned as the control group. Researcher prepared worksheets which were related to acid- based concepts based on guided inquiry instruction from the book which is written by (Moog and Farrell, 2006). The experimental group was cooperatively studied worksheets in the groups while the control group was individually studied worksheets in the class. Acid and Bases Achievement Test (ABAT) was administered to the experimental and the control groups as pre and post-tests to measure the students’ understanding of acid and bases concepts and Attitude Toward Guided Inquiry Instruction Scale (ATGIIS) was also used as pre and post-test for both of groups. Multi Variance Analysis (MANOVA) was used to analyze the data. The results showed that students in the experimental group had better understanding of acid and bases concepts and more positive attitude toward guided inquiry instruction. Key words: Guided inquiry, cooperative learning, acid and bases.

Biodegradation of vegetable oils: a review.

Abstract: Vegetable oils have traditionally been applied in food uses, but recent trends suggest their economic usefulness as industrial fluids. Increasing crude oil prices and emphasis on the development of renewable, environmentally friendly industrial fluids have brought vegetable oils to a place of prominence. Biodegradability provides an indication of the persistence of any particular substance in the environment and is the yardstick for assessing the eco friendliness of substances. The superior biodegradation of vegetable oils in comparison with mineral based oils has been demonstrated severally, leaving scientists with the lone challenge of finding economic and safe means to improve their working efficiency in terms of their poor oxidative stability and high pour points. Keywords: Biodegradability, oxidative stability, environment, eco friendliness, renewable.

Hydrogels as potential drug delivery systems

Abstract: Hydrogels, the swellable polymeric materials, have been widely investigated as the carrier for drug delivery systems. These biomaterials have gained attention owing to their peculiar characteristics like swelling in aqueous medium, pH and temperature sensitivity or sensitivity towards other stimuli. Hydrogels being biocompatible materials have been recognized to function as drug protectors, especially for peptides and proteins, from in vivo environment. Also these swollen polymers are helpful as targetable carriers for bioactive drugs with tissue specificity. This article presents an overview to the advances in hydrogel based drug delivery that have become the interest of most researchers. Key words: Hydrogels, pH sensitivity, temperature sensitivity, glucose sensitivity, biodegradable.

The study of cow dung as co-substrate with rice husk in biogas production

Abstract: The co-digestion of cow dung with rice husk for biogas production at laboratory scale was the subject of this investigation. The study was carried out at room temperature that is, 26 - 29°C for a period of 52 days with a total solid concentration of 8% in each sample (fermentation slurry). The biogas produced was collected by water displacement method which was subsequently measured. Sample A (50 wt % cow dung, 50 wt % rice husk) showed a cumulative biogas production of 161.5 ml at the end of the 38th day of the experiment after which there was no further production. The production from sample B (25 wt % cow dung, 75 wt % rice husk) was not significant, while there was no production from sample C(0 wt % cow dung, 100 wt % rice husk). Key words: Biogas, cow dung, rice husk, co-digestion.

Application of analytical hierarchy process in the design concept selection of automotive composite bumper beam during the conceptual design stage

Abstract: Selection of design concepts is an area of design research that has been under considerable interest over the years. The level of success of product designs achieved depends significantly on the initial concept at the conceptual design stage. Inappropriate decision making during design concepts selection at the conceptual design stage can cause the product to be redesigned or remanufactured. To overcome such problem, this paper proposed a concept selection model called concurrent design concept selection and materials selection (CDCSMS) to assist designers in selecting the most appropriate design concepts and materials for automotive composite components at the conceptual design stage using analytical hierarchy process (AHP). To illustrate the proposed model, 8 design concepts of automotive composite bumper beam are considered and the most appropriate one is determined by using the analytical hierarchy process (AHP). The final decision was carried out by performing the sensitivity analysis in order to study the effect of the different factors on deciding the best decision option. Key words: Analytical hierarchy process (AHP), design concept selection, conceptual design stage, automotive bumper beam.

Virtual R&D teams in small and medium enterprises: a literature review

Abstract: Small and medium enterprises (SMEs) are the driving engine behind economic growth. While SMEs play a critical role in generating employment and supporting trade, they face numerous challenges, the prominent among them are the need to respond to fasting time-to-market, low-cost and rapid solutions to complex organizational problems. Towards that end, research and development (R & D) aspect deserves particular attention to promote and facilitate the operations of SMEs. Virtual R & D team could be a viable option. However, literature shows that virtual R & D teaming in SMEs is still at its infancy. This article provides a comprehensive literature review on different aspects of virtual R & D teams collected from the reputed publications. The purpose of the state-of-the-art literature review is to provide an overview on the structure and dynamics of R & D collaboration in SMEs. Specifying the foundation and importance of virtual teams, the relationship between virtual R & D team and SMEs has been examined. It concludes with the identification of the gaps in the existing literatures and calls for future research. It is argued that setting-up an infrastructure for virtual R & D team in SMEs still requires a large amount of engineering efforts and deserves consideration at top level management.

AMMI and SREG GGE biplot analysis for matching varieties onto soybean production environments in Ethiopia

Abstract: Matching soybean variety selection with its production environment is often challenged by the occurrence of significant genotype-by-environment interactions (GEI) in the variety development process. Several statistical models have been proposed for increasing the chance of exploiting positive GEI and supporting breeding program decisions in variety selection and recommendation for target set of environments. Additive main effects and multiplicative interactions (AMMI) and site regression (SREG) genotype plus genotype-by-environment interaction (GGE) models are among the models that effectively capture the additive (linear) and multiplicative (bilinear) components of GEI and provide meaningful interpretation of multi-environment data set in breeding programs. The objective of this study was to assess the significance and magnitude of GEI effect on soybean grain yield and exploit the positive GEI effect using AMMI and SREG GGE biplot analysis. Grain yield data of 11 genotypes evaluated at 4 sites for three cropping seasons (2002, 2003 and 2004) across the soybean production ecology in Ethiopia were used for this purpose. AMMI analysis showed that grain yield variation due to environments, genotypes and GEI were highly signifiscant (p<0.01). Environments explained the greater proportion (61.08%) of total yield variation followed by GEI (34.13%) and genotypes (4.79%), indicating the necessity for testing soybean varieties at multi-locations and over years. The first five bilinear AMMI model terms were highly significant (p<0.01) and of which the first two terms explained 67.5% of the GEI. According to the AMMI and SREG GGE biplots models, no single variety has superior performance in all the environments. However, the genotype TGx-1892-10F was overall winner in combining high yield with relatively less variable yield across environments. Application of AMMI and GGE biplots facilitated visual comparison and identification superior genotypes for each target set of environments. Key words: AMMI, GGE biplot, genotype-by-environment interaction, soybean, Ethiopia.

Apricot culture in Turkey.

Abstract: Turkey is divided into nine agro-ecological regions with mountainous terrain in the periphery, a relatively flat central plateau and a narrow coastal strip. This country has diverse environment with mountains, valleys, plains and numerous rivers and lakes. Over a quarter of the country is covered with forests and woodlands. This results in marked variations in climate and vegetation around the country. Turkey and Iran (Iran Plateau) are centers of origin and diversity of many fruit species, such as apple, pear, cherry, rose, walnut, cornelian cherry, almond and more. Stone fruits comprise 20.0% of the total fruit production in Turkey, and apricot ranks first among stone fruits. Apricot can be grown in all regions of Turkey, except in the Eastern Black Sea Region and in the high plateaus of the East Anatolian Region. Turkey is a leading producer in both in fresh and dried apricots in the world. Although the percentage share of the fresh apricot trade is not significant, Turkey can enlarge this potential in the near future.

Incidence of Urinary Tract Infections (UTIs) among pregnant women in Akwa metropolis, Southeastern Nigeria

Abstract: This study reports the bacteriological aetiology and incidence of Urinary Tract Infections (UTIs) among pregnant women attending antenatal clinics at hospitals in Akwa metropolis, Southeastern Nigeria. A total of 100 mid-stream urine samples were collected and cultured for the presence of bacterial pathogens, 54 showed significant bacterial growth while 46 showed no significant bacterial growth. Bacterial agents were isolated from 54 pregnant women and were identified as: Escherichia coli; Klebsiella spp., Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis. Escherichia coli [20(37%)] was the commonest offending bacterial pathogen isolated. Other bacterial pathogens incriminated in this study were Klebsiella spp. [11(20.4%)], Proteus mirabilis [9(16.7%)], Pseudomonas aeruginosa [7(13%)], Staphylococcus aureus [4(7.4%)] and Staphylococcus epidermidis [3(5.6%)]. The study indicated a high incidence of UTIs (54%) though most of the pregnant women showed no clinical manifestation.

The use of expanded microteaching for reducing pre- service teachers' teaching anxiety about mathematics

Abstract: The purpose of this study was to investigate the effects of expanded microteaching on the pre-service mathematics teachers’ teaching anxiety in teaching practicum course. There were 43 pre-service mathematics teachers divided into 2 groups, experimental and control groups, involved in the study. The experimental group contained 21 (12 females and 9 males) and control group contained 22 pre-service mathematics teachers (10 females and 12 males). The pre-service mathematics teachers in experimental group were lectured using expanded microteaching at the secondary school they were assigned to. Those who were in control group were lectured in a traditional way at another secondary school. Mathematics teaching anxiety scale (MATAS) was administered to pre-service teachers before and after eight weeks of teaching period. After collecting the data, the researcher used the independent samples t-test and ANCOVA to analyze the quantitative data. Results showed that there were statistically significant difference found regarding teaching anxiety between the control and experimental groups favoring the experimental group. In other words, using of the expanded microteaching in teaching practicum course reduced the teaching anxiety levels of pre-service mathematics teachers. Key words: Teacher training, microteaching, expanded microteaching, teaching anxiety, mathematics, pre-service teacher.

Evaluation of noise pollution caused by vehicles in the city of Tokat, Turkey

Abstract: Noise pollution and its influence on environment and life quality of human beings may be considered as a hot topic in scientific research. Since there are no sufficient studies on noise pollution in Turkey, this study was carried out to determine motorway noise levels in Tokat city centre, located at the northern part of Turkey. Noise measurements were taken in the evening to determine noise pollution all over the city as motorway transportation noise. The equivalent sound levels - Leq- were measured at 65 points, between 17 and 19 p.m. in the city. High noise levels on these streets were observed throughout the city. At fifty of sixty-five measurement points (76.9%), noise values exceeded 65 dB(A), limit value according to Turkish noise control regulation, while at fifteen points (23.1%) this value was under this value. Statistical analysis revealed that, there were significant differences in noise levels amaong the streets (P < 0.05). The results showed that noise should be mentioned among the major environmental problems and studies aim at preventing it should have great priority. Keywords: Tokat, noise, motorway, noise pollution, survey.

Impact of charcoal production on woody plant species in West Africa: A case study in Togo

Abstract: In Togo, fuel wood and charcoal account for more than 80% of total householdenergy requirements. Charcoal production results in a high pressure on the commonly used woody species. This study was carried out to assess the impact of charcoal production on the vegetation. Surveys involving 310 charcoal producers from 4 production areas were carried out. In each production area, density, diameter, height and basal area of woody species were measured both in unexploited plots and exploited plots. Inside the 4 charcoal production areas, 158 woody species were identified including 34 regularly exploited for charcoal production, that is, 15 preferred and 19 by default. Diversity indexes (Species Richness, Shannon and Evenness) and variability of densities are significantly higher in unexploited plots than those in exploited plots. The average heights vary between 4 and 7 m inside the exploited plots and from 6 to 9 m inside the unexploited plots. Average diameter and basal area are statistically not different inside unexploited plots and exploited plots. The most common regeneration methods inside the 4 charcoal production areas are seedlings and coppices. The preferred species regenerate better in exploited plots than those exploited by default. The study concludes that the negative effect of charcoal production on natural ecosystems has resulted in the depletion of the biodiversity, density, height, diameter of the stands and basal area of the woody species. Key words: Charcoal production, plant diversity, woody population structure, regeneration.

Chromatographic analysis of vegetable oils: a review.

Abstract: Vegetable oils has become more attractive recently because of its economical benefits as they are used as components in many manufactured products and the fact that it is made from renewable resources. The determination of the minor components is of great importance in establishing the oil quality and their genuineness. The qualitative and quantitative determination of the constituents is done by gas chromatography of compounds or their derivatives. High precision in the gas chromatographic analysis of fatty acid methyl esters is possible with careful attention to detail during sample preparation, injection, chromatographic and data collection. This paper shows the applications of solid-phase extraction for the isolation of certain lipid classes prior to chromatographic analysis and also the most commonly used chromatographic techniques that can be applied for accuracy. Key words: Chromatography, component, fatty acid methyl esters, sterol.

Antibacterial activity of oleo-gum resins of Commiphora molmol and Boswellia papyrifera against methicillin resistant Staphylococcus aureus (MRSA)

Abstract: The petroleum ether, ethyl acetate, methanol and water extracts of the oleo-gum resins of two Arabian medicinal plants, Commiphora molmol Engl. ex Tschirch andBoswellia papyrifera Hochst were investigated for their antibacterial activity against methicillin resistant Staphylococcus aureus (MRSA). The phytochemical investigation demonstrated the presence of phenolic compounds, alkaloids and saponins in the methanol extracts which is lacking in the petroleum ether and ethyl acetate extracts. The methanol extracts exhibited the highest antibacterial activity whereas the ethyl acetate extracts exhibited some degree of activity and the petroleum ether and water extracts exhibited no or least activity. The minimum inhibitory concentration (MIC) ranged between 31.25 and 250 µg/ml for oleo-gum resin methanol extract of C. molmol and of B. papyrifera ranged from 62.5 to 500 µg/ml, respectively. Key words: Commiphora molmol, Boswellia papyrifera, Staphylococcus aureus,MRSA, antibacterial activity.

Deformations and stresses in rotating FGM pressurized thick hollow cylinder under thermal load

Abstract: Using the infinitesimal theory of elasticity, closed form solutions for one-dimensional steady-state thermal stresses in a rotating functionally graded (FGM) pressurized thick-walled hollow circular cylinder are obtained under generalized plane strain and plane stress assumptions, respectively. The material properties are assumed to vary nonlinearly in the radial direction and the Poisson’s ratio is assumed constant. The temperature distribution is assumed to be a function of radius, with general thermal and mechanical boundary conditions on the inside and outside surfaces of the cylinder. The direct method is used to solve the heat conduction and Navier equations. The steady-state temperature, displacements and stresses distributions depending on an in homogeneity constant are compared with those of the homogeneous case and presented in the form of graphs. The values used in this study are arbitrary chosen to demonstrate the effect of in homogeneity on displacements, and stresses distributions. Key words: FGM, hollow circular cylinder, rotating, thermal stresses, elasticity.

Allelopathic effect of Tithonia diversifolia on the germination, growth and chlorophyll contents of maize (Zea mays L.).

Abstract: The allelopathic effects of fresh shoot aqueous extract of Tithonia diversifolia(Hemsl.) A. Gray was investigated on the germination of seeds and growth of young seedlings of Zea mays L. Although the fresh shoot aqueous extract did not show significant allelopathic effect on the germination of Z. mays, however, the radicle and plumule lengths of the seedlings were significantly inhibited by the fresh shoot aqueous extract. Also, the fresh shoot aqueous extract of T. diversifolia was found to significantly stimulate the growth of older plants of two weeks old and above. The application of fresh shoot aqueous extract of T. diversifolia was observed to significantly enhance the following growth parameters: fresh weight, dry weight, leaf area and ratio. In addition, chlorophyll a, chlorophyll b and total chlorophyll accumulation were reduced in these young plants. The study was able to reveal that fresh shoot aqueous extract of T. diversifolia could have differing effects (inhibitory and stimulatory), on seedling growth of this test crop, depending on plants growth stage. Key words: Allelochemicals, allelopathy, fresh shoot aqueous extract, inhibitory, stimulatory, Tithonia diversifolia, Zea mays.

An experimental investigation into the buckling of GFRP stiffened shells under axial loading

Abstract: The results of an experimental study on the buckling behavior of thin-walled GFRP cylindrical shells are presented. The specimens were fabricated from continuous glass fiber using a specially-designed filament winding machine. The buckling behaviors of unstiffened shells and stiffened shells with lozenge, triangular and hexagonal grids were then studied under quasi-static axial loading at room temperature. Due to the thin skin of the shells, all specimens first experienced a general buckling mode as well as barreling under the applied loading. Following this general buckling damage, local buckling mode was seen on all specimens. Based on the experimental results, the critical buckling load was higher for the shells with hexagonal and triangular grids while the unstiffened shells and stiffened shells with lozenge grids exhibited much lower critical buckling load. On the other hand, in very small skin thicknesses, when the specific buckling loads for all specimens were compared, the unstiffened shells showed the highest specific buckling load. Key words: Buckling load, composite shells, stiffened shells.

Towards developing an improved methodology for evaluating performance and achieving success in construction projects

Abstract: Success has always been the ultimate goal of every activity and a construction project is no exception. The construction industry has characteristics that sharply distinguish it from her sectors of the economy, causing the rate of failures to become very high. However, the prospect of business failure is not a topic that most businesses care acknowledges. Understanding the mechanism of failure is the key to avoid failure. Corrective action cannot be taken if trouble is not acknowledged or foreseen (Kangarl, 1988). By its very nature, the construction industry is contentious and filled with a wide variety of disputes. Even the best-managed project is likely to have one or more significant disputes which may imperil the successful completion of the project. If project participants can predict probability of success better, they can take steps to avoid unsuccessful projects; identify good projects worth pursuing; and identify problems on current projects and take corrective action. In this hostile and competitive environment it is critical to know and understand more about performance evaluation and success criteria and its impacts in construction (Halpin and Woodhead, 1980). The main objective of this paper is to define the critical factors that lead to project success and provide a forecasting framework to enable parties to rapidly assess the possibility of a successful project from their viewpoint. The previous objective was divided into the following secondary objectives: Providing background information on construction evaluation techniques. Distinguish factors influencing project success. Presenting a hierarchical model framework for construction project success. This paper provides a rational framework to further develop a conceptual framework to a substantive predictive model aiming to increase the likelihood of achieving more successful project outcomes through pre­dicting and subsequently preventing construction failure, and analyzing the effects of various conditions and fluc­tuating economic environments on the construction project. Key words: Success criteria, failure, construction projects, framework, methodology.

The use of Psidium guajava Linn. in treating wound, skin and soft tissue infections.

Abstract: The antibacterial potential of the crude leaves extracts of Psidium guajava Linn. against some bacteria associated with surgical wound, burns, skin and soft tissue infections were investigated under different conditions. Phytochemical screening of the crude leaves extracts revealed the presence of some bioactive compounds that have been associated with antimicrobial activities. Aqueous extracts was more potent in inhibiting the growth of pathogenic Proteus mirabilis, Streptococcus pyogenes, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa than the organic extracts. The gram-negative bacteria were less susceptible to the effects of the crude drugs. The MIC and MBC values ranged between 6.25 - 50 mg/ml, depending on extracting solvent and the bacterium in question. Based on the diameters of zones of growth inhibitions, the crude extracts were more effective under acidic conditions and also at low temperatures. The plant can be used for the formulation of oral antibacterial drugs to manage surgical, skin and soft tissue infections. Key words: Psidium guajava, antibacterial potential, bioactive compounds, surgical, soft tissue.

Prediction of mechanical properties of cement containing class C fly ash by using artificial neural network and regression technique

Abstract: The aim of this study is to investigate the estimation ability of the effects of utilizing different amount of the class C fly ash on the mechanical properties of cement using artificial neural network and regression methods. For this reason, 0, 5, 10, 15 and 20% amount of the class C fly ash were substituted with cement and 40 x 40 x 160 mm dimension specimens were prepared. On the prepared specimens unit weight, flexural tensile strength and compressive strength tests were performed after the 2, 7 and the 28th days. 2 different estimation models regression techniques (RT) and the artificial neural network (ANN) methods were used for determining the flexural tensile strength and the compressive strength of the cement specimens. Experimental results were used in the estimation methods. Fly ash content (%), age of specimen (day) and unit weight (g/cm³) were used as input parameters and flexural tensile and compressive strengths (N/mm²) were used as output parameters. The developed models and the experimental results were compared in the testing data set. As a result, compressive and flexural tensile strength values of mortars containing various amounts class C fly ash can be predicted in a quite short period of time with tiny error rates by using the multilayer feed-forward neural network models than regression techniques. Key words: Fly ash, cement, flexural tensile strength, compressive strength, regression, ANN.

Post-market in vitro bioequivalence study of six brands of ciprofloxacin tablets/caplets in Jos, Nigeria

Abstract: Six brands of ciprofloxacin 500 mg tablets have been evaluated using some quality control tests of uniformity of weight, hardness, friability, assay, disintegration and dissolution with the aim to assess its bioequivalence. The results obtained have been discussed in some details using monographs in the two Pharmacopeia (United States Pharmacopeia, USP and British Pharmacopeia, BP). The results were also subjected to statistical analysis. In particular, the dissolution test results were subjected to further tests to determine significance of ANOVA, significance of Dunnett’s test, dissolution efficiency, difference factor (f1) and similarity factor (f2). Subsequently the results indicated that 3 of the 6 (50%) brands may not be used interchangeably with the chosen ‘innovator’ brand.

Enzyme cocktail for enhancing poultry utilisation of cocoa pod husk

Abstract: Cocoa Pod Husk (CPH) is a major by-product from the cocoa industry in Ghana. Using CPH as a low-cost unconventional feedstuff is hampered by its poor nutrient composition due to high level of non-starch polysaccharides including cellulose, pectin and hemicellulose, which are indigestible in monogastric livestock such as poultry. Anin vitro enzyme treatment study was conducted to test the effect of various combinations of selected exogenous fibrolytic enzymes on the digestibility of CPH feedstuff. Concentrations of 0.8, 0.6 and 0.8% w/w respectively for Pentopan®MonoBG, Viscozyme®L and Pectinex®5XL were observed as appropriate levels for supplementing CPH feedstuff. Among the enzyme combinations tested, the Pentopan®MonoBG + Viscozyme®L, Viscozyme®L + Pectinex®5XL and Pentopan®MonoBG + Viscozyme®L + Pectinex®5XL formulae were most effective in maximising sugar release from CPH feedstuff by 42 - 53% increase with a corresponding reduction (7 - 14%) in crude fibre and non-starch polysaccharide fractions (P < 0.05). The present results suggest that supplementation with multi-enzymes or blends of exogenous NSP-degrading enzymes may enhance the capacity of poultry to efficiently digest and utilise dietary CPH. Key words: Agro-industrial by-product, cocoa pod husk, non-starch polysaccharides,in vitro treatment, fibrolytic enzymes, saccharification.

A comparison of problem-based learning and traditional lecture students' expectations and course grades in an introductory physics classroom

Abstract: The purpose of this study was to compare problem-based learning (PBL) and traditional lecture students’ expectations about physics and physics learning and course grades in an introductory physics classroom. A total of 264 (PBL, n = 100; traditional, n = 164) freshman engineering students of Dokuz Eylul University (DEU) in Izmir, Turkey participated in the study. Student expectations were measured through the pre and post application of the Maryland Physics Expectations Survey (MPEX). Physics achievement data were obtained from students’ end-of-semester physics grades. Data were analyzed using the analyses of variance (ANOVA), the repeated measure and multivariate analysis of variance (MANOVA) statistics. Results revealed that groups did not differ in their average MPEX scores as a result of one semester of instruction. Significant differences were determined in some components of the MPEX with respect to gender and instruction type. Overall, results of this study suggest that PBL approach has no positive influence on students’ achievement in and expectations about physics and physics learning for this particular group of students. Implications of the results for physics education and further research are discussed. Key words: Expectations, introductory physics, problem-based learning, MPEX.

Effect of temperature on development and survival of Bactrocera correcta (Diptera: Tephritidae)

Abstract: The effect of temperature on the development and survival of the guava fruit fly,Bactrocera correcta (Bezzi) (Diptera: Tephritidae) from egg to adult’s pre-ovipositional stage was studied in laboratory under 5 different constant temperatures: 18, 24, 30, 33 and 36°C. The developmental time of the egg, larva and pupa significantly decreased with increasing temperature from 18 to 33°C. The developmental rate of the pre-oviposition stage reached physiological maximum at the higher temperature (36°C). At 18°C, no female oviposited. The survival rate reached maximum at 24 - 33°C and decreased at higher or lower temperature. The lower developmental thresholds, thermal constants and lethal high temperatures for different life stages of the fly were also estimated. The results will be useful for the predicting the fly’s population dynamics and geographical distribution, which would help develop the fly management strategies. Key words: Guava fruit fly, temperature-dependent development, lower developmental threshold, thermal constant, lethal high temperature.

Inhibition of the corrosion of mild steel in H2SO4 by penicillin G

Abstract: Inhibitive and adsorption properties of penicillin G for the corrosion of mild steel was investigated using gasometric and thermometric methods. Penicillin G is found to inhibit the corrosion of mild steel in H2SO4. Inhibition efficiencies of penicillin G increased as the concentration of penicillin G increases but decreased with increase in temperature. Penicillin G is found to act as an adsorption inhibitor for the corrosion of mild steel. The adsorption of the inhibitor on the surface of mild steel was found to be exothermic, spontaneous and followed the mechanism of physical adsorption. Also Langmuir adsorption isotherm was found to be the best isotherm that described the adsorption characteristics of the inhibitor. Key words: Corrosion of mild steel, inhibition, penicillin G.

Antibacterial efficacy of stem bark extracts of Mangifera indica against some bacteria associated with respiratory tract infections

Abstract: Phytochemical screening of the crude stem bark extracts of Mangifera indicarevealed the presence of alkaloids, phenols, tannins, saponins and cardiac glycosides. The antibacterial activity of the crude extracts were assayed using the agar well diffusion methods on clinical bacterial isolates of Escherichia coli,Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia andStreptococcus pneumonia obtained from patients previously diagnosed with respiratory tract infections. At a concentration of 50 mg/ml, the crude extracts inhibited the growth of all the respiratory tract pathogens, though with varying degrees of susceptibility depending on the bacterium and the extracting solvent. The MIC values ranged from 12.5 - 200 mg/ml, while the MBC values ranged from 50 - 400 mg/ml and this is very important for people who depend on the plant for their health care needs. The presence of the bioactive compounds has been linked to the antimicrobial activity of the extracts. The activity of the crude drug was more under acidic conditions and at elevated temperatures. The results obtained in this study support the use of the plant in herbal medicine. The stem bark of the M. indica tree can be used as a source of broad spectrum oral antibiotic to fight respiratory tract pathogens. Key words: Phytochemical screening, Mangifera indica, bioactive, herbal medicine, respiratory tract, pathogens.

Effect of wood moisture content on adhesion of varnish coatings

Abstract: In this research, experimental samples were prepared using Scots pine (Pinus sylvestris L.), Eastern beech (Fagus orientalis L.) and oak (Quercus petraea L.) with moisture content of 8, 12 and 15% and were coated with cellulosic (nitrocellulose), two-part polyurethane (urethanealkyd), and waterborne (self-crosslinked polyurethane) varnishes in order to determine the effect of wood moisture content on adhesion. According to research results, it was found that the difference in moisture content had substantial effect on the adhesion of varnishes, applied on the wood surfaces. The highest adhesion was obtained from two-part polyurethane varnish, applied on oak specimens with a moisture content of 8%.

The effects of petroleum dependency on agricultural trade in Nigeria: An error correlation modeling (ECM) approach

Abstract: Agricultural and petroleum sectors are both of great importance to the Nigerian economy in terms of their contribution to Gross Domestic Product (GDP) and value of their exports. Dependence of Nigeria on the oil sector has been found to adversely affect both the agricultural sector and the economy. This study covered the periods between 1970 and 2003. It sought to know the effects and extent of petroleum dependency (in terms of oil exploration, production and trade) on the agricultural sector using Co-integration and Error Correction Modeling (ECM) analysis. Time series data were obtained from Central Bank of Nigeria (CBN), Food and Agricultural Organization (FAO), Federal Office of Statistics (FOS), National Institute for Social and Economic Research (NISER) and Federal Ministry of Agriculture and Rural Development. The study revealed that the trend in production levels of major export crops increased in recent years. Results from the analysis showed the presence of at least one co-integrating vector for all the crops. The result of the ECM confirmed a long run equilibrium relationship between the cash crops and the exogenous variables; and also the presence of significant short-run dynamics or divergences. The Ordinary Least Squares (OLS) results showed that the value of oil exports and imports increased with agricultural production. However, the quantity of oil production had an inverse relationship with the output of agricultural export crops. Based on the results, workable recommendations were made for improving the agricultural sector and reducing the adverse effects of petroleum dependency on agricultural trade and the economy at large. Key words: Petroleum dependency, agricultural production, error correction model (ECM), Nigeria.