Assessment of Pb, Zn, As, Ni, Cu, Cr and Cd in Agricultural Soils around Settlements of Abandoned Lead-Zinc Mine in Mkpuma Ekwoku, South-eastern, Nigeria

This study was carried out to assess the level, distribution and the contamination status of Pb, Zn, As, Ni, Cu, Cr and Cd in agricultural soils around the settlements of Abandoned Lead-Zinc Mine in Nkpuma Ekwoku, Southeastern, Nigeria. The mean concentrations of the heavy metals, Pb, Zn, As, Ni, Cu, Cr and Cd are 109.55, 210, 1.83, 2.34, 8.24, 12.66 and 8.57 mg/kg respectively. The values obtained were compared with the established soil sediment standard by Canadian Council of Ministers of Environment (CCME). Generally most samples around the abandoned Pb/Zn mine show higher concentration of Pb, Zn, Cd, and Cr compare to individual Effect Range Low (ERL) values of the elements while Cu, and Ni were below both Effect Range Low (ERL) and Effect Range Medium values. However, Cd and Cr exceed the Effect Range Medium of the elements. Pollution Load Index (PLI) was found to be generally low in all the locations whereas the contamination factor (CF) values for metals like Pb, Zn and Cd are >1 while CF values of As, Cu, Cr and Ni are <1. The contamination is most probably resulted from the mineralized veins and mining of the ores.Keywords: heavy metals; soil contamination; lead-zinc; Mkpuma-Ekwok

Domestic market potential for tree products from farms and rural communities: Experience from Cameroon

This publication summarizes the results of research carried out by NRI in Cameroon during 1995-96 on the domestic market potential for tree products from farms and rural communities. The study arose from concern that agroforestry projects, which generally aim to reduce the pressure on natural forests by planting trees on farmland, were inadequately addressing the associated marketing needs. As a consequence, many of the projects were failing. The research reported here sought to characterize the markets for non-timber tree products (NTTPs) and highlight constraints to the development of markets for traditional and emerging NTTPs. The research in Cameroon was paralleled by a study in the Brazilian Amazon carried out by IFPRI; ODA provided funding for both studies. The work began with an inventory of products and subsequent identification of marketing chains. Four products were selected as case studies and were used to explore issues relating to valued added, domestication and the role of NTTPs as sources of income. The marketing of the four products was well-established and appeared to be relatively competitive, in spite of some concerns over lack of information at farmer level. There was growing demand for the products, apparently matched by increasing supply. The wholesalers, who source the products in the forest fringe communities and sell them on to retailers, were the most dynamic links in the marketing chains. The impetus to domesticate NTTPs seemed always to be farmer-driven, and occurred when a product important for subsistence and income needs was not readily available from the forest. However, the role of NTTPs within the farming system is important; they must fit into a complex strategy which includes seasonal smoothing of income, production and labour needs. Also, tree-planting is a long-term investment which is unlikely to be undertaken if land tenure is insecure. In conclusion, areas are highlighted for future research. These include: technical aspects of cultivation, processing and storage; identification of products which will be in greater demand as a result of urbanization; the role of NTTPs in the livelihood strategies of particularly vulnerable groups (including the landless) in the forest fringe communities

Evaluation of Content and Chapter Summaries of Approved Basic Science Textbooks in Ebonyi State Junior Secondary Schools in Nigeria

This study evaluated the topical coverage and chapter summaries of 12 (twelve) approved basic science textbooks in Ebonyi State junior secondary schools. The study was carried out in Ebonyi State of Nigeria. Two research questions and one hypothesis guided the study. Evaluation research design was adopted. One instrument was used, A 5-point quantitative approach for content evaluation of science textbooks (QACEST). QACEST formula was used to answer research questions while the null hypothesis was tested using chi-square test of goodness of fit. The result revealed among others; STAN basic science project, spectrum basic science, basic science for upper basic all had adequate topical coverage while basic science for Nigerian junior secondary school had topical coverage inadequate. The study also identified that chapter summaries of 9 basic science textbooks out of twelve (12) basic science textbooks evaluated are inadequate. The remaining four (4) basic science textbooks do not have chapter summaries at all. Based on the findings, the study recommended that all basic science textbooks use for teaching students need to be periodically revised with the view to make them to have acceptable content validity and enrich them in terms of content and chapter summary. That authors and publishers of any basic science textbooks should consult basic science core-curriculum in order to draw topics, objectives, contents and activities from the core-curriculum. Keywords: Basic Science, Topical Coverage, Chapter Summary, Evaluation Research, QACEST

Experimental neoichnology of crawling stalked crinoids

Stalked crinoids have long been considered sessile. In the 1980s, however, observations both in the field and of laboratory experiments proved that some of them (isocrinids) can actively relocate by crawling with their arms on the substrate, and dragging the stalk behind them. Although it has been argued that this activity may leave traces on the sediment surface, no photographs or images of the traces produced by crawling crinoids have been available. Herein, we present results of neoichnological experiments using the shallowest species of living stalked crinoid, Metacrinus rotundus, dredged from Suruga Bay (near the town of Numazu, Shizuoka Prefecture, ~ 140 m depth). Our results demonstrate that isocrinids produce characteristic locomotion traces, which have some preservation potential. They are composed of rather deep and wide, sometimes weakly sinuous, central drag marks left by the stalk and cirri, and short, shallow scratch marks made by the arms. Based on the functional morphology and taphonomy, it has been argued that the ability to autotomize the stalk and relocate had already evolved in the oldest stem-group isocrinids (holocrinids), likely in response to increased benthic predation pressure during the so-called Mesozoic marine revolution. Our data show that this hypothesis may be corroborated in the future by ichnological findings, which may provide more direct proof of active locomotion in Triassic holocrinids

Race, Skin Color and Genetic Ancestry: Implications for Biomedical Research on Health Disparities

Defining race continues to be a nemesis. Knowledge from human genetic research continuously challenges the notion that race and biology are inextricably linked, with implications across biomedical and public health disciplines. While it has become fashionable for scientists to declare that race is merely a social construction, there is little practical value to this belief since few in the public believe and act on it. In the U.S., race has largely been based on skin color and ancestry, both of which exhibit large variances within communities of color. Yet biomedical studies continue to examine black / white group differences in health. Here we discuss why using race in biomedical studies is problematic using examples from two U.S. groups (African and Hispanic Americans) which transcend ‘racial’ boundaries and bear the burden of health disparities

Introducing Misoprostol for the Treatment of Incomplete Abortion in Nigeria

Despite legal restriction, induced abortions and resulting complications are common in Nigeria. Misoprostol administration for incomplete abortion was introduced in 3 Nigerian hospitals. The feasibility of the hospitals, patient and provider acceptability were assessed using questionnaire and interview guides administered to 205 women and 17 providers respectively. Amongst the women, 194 (95%) were satisfied and very satisfied with misoprostol, 176 (86%) would choose misoprostol again if another incomplete abortion occurred and 191 (93%) would recommend it to another woman in a similar situation. Providers were highly satisfied with misoprostol. The ease of use and ability to redirect surgical resources to more complicated issues were positive features cited by them. The providers agreed that integration of misoprostol was straightforward and required few resources. Therefore, misoprostol for incomplete abortion is safe, efficacious and acceptable to providers and patients. In remote areas of Nigeria with limited post-abortion care (PAC), misoprostol administration is an important potential PAC treatment modality. Features of misoprostol-low cost, room temperature stability, and ease of introduction-render it an important treatment option, particularly in low resource and rural settings

Thermohydrodynamics in Quantum Hall Systems

A theory of thermohydrodynamics in two-dimensional electron systems in quantizing magnetic fields is developed including a nonlinear transport regime. Spatio-temporal variations of the electron temperature and the chemical potential in the local equilibrium are described by the equations of conservation with the number and thermal-energy flux densities. A model of these flux densities due to hopping and drift processes is introduced for a random potential varying slowly compared to both the magnetic length and the phase coherence length. The flux measured in the standard transport experiment is derived and is used to define a transport component of the flux density. The equations of conservation can be written in terms of the transport component only. As an illustration, the theory is applied to the Ettingshausen effect, in which a one-dimensional spatial variation of the electron temperature is produced perpendicular to the current.Comment: 10 pages, 1 figur

Thermoelectric Response of an Interacting Two-Dimensional Electron Gas in Quantizing Magnetic Field

We present a discussion of the linear thermoelectric response of an interacting electron gas in a quantizing magnetic field. Boundary currents can carry a significant fraction of the net current passing through the system. We derive general expressions for the bulk and boundary components of the number and energy currents. We show that the local current density may be described in terms of ``transport'' and ``internal magnetization'' contributions. The latter carry no net current and are not observable in standard transport experiments. We show that although Onsager relations cannot be applied to the local current, they are valid for the transport currents and hence for the currents observed in standard transport experiments. We relate three of the four thermoelectric response coefficients of a disorder-free interacting two-dimensional electron gas to equilibrium thermodynamic quantities. In particular, we show that the diffusion thermopower is proportional to the entropy per particle, and we compare this result with recent experimental observations.Comment: 18 pages, 2 postscript figures included. Revtex with epsf.tex and multicol.sty. In the revised version, the comparison with experimental observations at $\nu=1/2, 3/2$ is extended to include the possibility of corrections due to weak impurity scattering. The conclusions that we reach regarding the applicability of the composite fermion model at these filling fractions are not affecte

Bio-oil production from co-pyrolysis of rice husk and plastic waste

Bio-oil has been produced from the co-pyrolytic reaction of rice husk and 2 grades of plastic wastes (LDPE and PET). The effect of catalysis on the yield was considered while the physicochemical properties of the products were evaluated and a comparison drawn between the properties of the oil and that of the commercial grade diesel. FT-IR and GC-MS analysis were also used to characterize the samples. Furthermore, the performance of a DI diesel engine was evaluated using both grades of oil. Results showed an improved yield of the oil through catalysis. The heating value and cetane number of the pyrolysis oil closely compared with commercial-grade diesel. Chemical compound identification through the GC-MS analysis showed the bio-oil to comprise mainly of aliphatic and aromatic hydrocarbons. FT-IR analysis of the by-product bio-char upon comparison with FT-IR analysis of the rice husk biomass confirmed the chemical modification of the biomass after the pyrolysis process.  From the result of this work, co-pyrolysis of both feedstock gave rise to high grade oil whose properties compares favorably with the commercial grade diesel. This is therefore an interesting alternative to fossil fuel whereas the improved properties indicate that it could have a better performance than a single biomass in terms of fuel properties

IMPACT OF INSTRUCTIONAL MATERIALS IN TEACHING AND LEARNING OF BIOLOGY IN SENIOR SECONDARY SCHOOLS IN

ABSTRACT. This study was designed to determine the impact of instructional materials in teaching and learning of Biology by SS II students in Yakurr local government area of Cross River state. In order to effectively handle the study, four research questions were formulated to guide the study. The descriptive statistical method was employed so as to determine the impact of teacher's effectiveness. Five (5) comparable secondary schools were selected to represent the population of the study. The data collected were analyzed using simple percentage method to verify the research questions formulated for this study. The result of the findings revealed that there is a positive achievement in students taught by highly qualified biology teachers and those exposed to instructional materials during lessons. It was recommended that government make available to schools the basic instructional materials as this will enhance an effective teaching and learning process