School head leadership style and its perceived influence on teachers' performance in Bikita District rural secondary schools of Masvingo Province

A study aimed at ascertaining the importance of shrewd management skills to a productive and motivated workforce in the education sector of Zimbabwe.This study was carried out to establish the perceived influence of school head leadership styles on teachers' performance. In this study the researchers used a mixed method research design that incorporated both the quantitative and qualitative approaches. The population consisted of ten school heads and sixty teachers, thus a total of seventy respondents. The research instruments were opened and closed ended questionnaire and semi-structured interview. The major findings revealed that the school heads in Bikita district of Masvingo province were generally perceived to display a high degree of democratic style of leadership based on the frequency of responses. It also emerged that leadership style of school heads influence performance of teachers. Calibre of students, teacher incompetence, lack of professional development and lack of motivation were also some of the factors that affected performance of some teachers

Changes in soil properties and plant uptake of heavy metals on selected municipal solid waste dump sites in Ile-Ife, Nigeria

In a study to evaluate the contributions of open municipal waste dump to soil heavy metals contamination and the modification of other soil physical and chemical parameters, soil samples were collected at various depths from the vicinity of major dump sites in Ile-Ife (latitudes 7°27' and 7°32', longitudes 4° 22' and 4° 29'), Nigeria. The samples when analyzed, showed that soils in the vicinity of dump sites had significantly higher pH regime compared to the control soil. Soils of the dump sites were found to be enriched with the heavy metals (Zn, Cu and Cd) more than the adjacent soils (control) but were still within tolerable /critical level with the exception of Pb which had a high value of 109.7 ugg-1 above the critical value of 100 ugg-1. There was significant relationship between the soil heavy metal content and plant uptake. Transfer factor (TF) expressed as the ratio of the heavy metal concentration in plants to that of soil varied significantly amongst the dump sites and also amongst the species of the heavy metals. The ten years old dump sites recorded the highest TF value ranging from 0.29 for Zn to 4.05 for Pb. The study therefore showed that changes in physico-chemical characteristics at dump sites could be attributed to interactions of different soil properties rather a single factor.Key words: Heavy metal contamination, seasonal changes, soil pH, soil texture, specific adsorption mechanism, transfer factor, food chain

Developing NGO competencies in post-disaster reconstruction: a theoretical framework

In the aftermath of recent natural disasters, NGOs have become increasingly involved in the permanent reconstruction of affected communities. These organizations, often operating well outside their expertise, encounter significant barriers as they implement reconstruction programmes. This paper presents the theoretical bedrock of a current research project, the overall goal of which is to design a competency-based framework model that can be used by NGOs in post-disaster reconstruction projects. Drawing on established theories of management, a unique perspective has been developed from which a competency-based reconstruction theory emerges. This theoretical framework brings together three distinct fields; Disaster Management, Strategic Management and Project Management, each vital to the success of the model. This theoretical study will incorporate a critical review of literature within each field. It is imperative that NGOs involved in post-disaster reconstruction familiarize themselves with concepts and strategies. It is hoped that the competence-based frame-work model that is produced on the basis of this theory will help define the standard of best practice to which future NGO projects might align themselves

Extraction, partial characterization and susceptibility to Hg2+ of acid phosphatase from the microalgae Pseudokirchneriella subcapitata Extração, caracterização parcial e susceptibilidade ao Hg2+ da fosfatase ácida da microalga Pseudokirchneriella subcapitata

Pseudokirchneriella subcapitata is a unicellular green algae widely distributed in freshwater and soils. Due to its cosmopolitan characteristic, its use is recommended by national and international protocols in ecotoxicity studies. The alteration of phosphatase activities by agriculture pollutants like heavy metals has been extensively used as a biomarker in risk assessment and biomonitoring. In this study, we compared the extraction of acid phosphatase from P. subcapitata by different procedures and we studied the stability, substrates specificity, kinetics and the effect of Hg2+ in the crude extract. The freezing and thawing technique associated with probe sonication was the most suitable method of extraction. The enzyme was stable when frozen at -20ºC for at least six months, showed an optimum pH of 5 and a Km value of 0.27 mM for p-nitrophenylphosphate (pNPP) as substrate. Some natural organic substrates were cleaved by a similar extent as the synthetic substrate pNPP. Short term exposure (24 hours) to Hg2+ had little effect but inhibition of the specific activity was observed after 7 days with EC50 (concentration of Hg2+ that promotes 50% decrease of specific activity) value of 12.63 &#956;M Hg2+.<br>Pseudokirchneriella subcapitata é uma alga verde unicelular amplamente distribuída em corpos d´agua e solos. Devido a sua natureza cosmopolita, seu uso é recomendado por protocolos nacionais e internacionais na realização de estudos de ecotoxicidade. A alteração da atividade de fosfatases por agentes poluentes de origem agrícola, como metais pesados, tem sido largamente usada como um biomarcador na avaliação de risco e biomonitoramento. No presente trabalho foi comparada a extração da fosfatase ácida de P. subcapitata por diferentes métodos e estudada a sua estabilidade, especificidade por substratos, cinética e efeito do Hg2+ no extrato bruto. O congelamento e descongelamento, associado com ultrassom, foi o método que proporcionou maior rendimento de extração. A enzima, praticamente estável por armazenamento a -20ºC, durante aproximadamente seis meses, demonstrou uma atividade ótima em pH 5 e um valor de Km para o p-nitrofenilfostato (pNPP) de 0,27 mM. Alguns substratos naturais foram hidrolisados com uma intensidade semelhante à do substrato sintético pNPP. Diferentemente dos estudos de exposição a curto prazo (24 horas), observou-se inibição da atividade específica nas culturas expostas durante 7 dias, com um valor de CE50 (concentração de Hg2+ que promove 50% de decréscimo da atividade específica) equivalente a 12,63 &#956;M Hg2+