649 research outputs found

    Interactions between the endocrine and immune systems in locusts

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    The prophenoloxidase cascade in the haemolymph of mature adult Locusta migratoria migratorioides (R & F) is activated in response to injection of laminarin, a -1,3 glucan. Co-injection of adipokinetic hormone-I (Lom-AKH-I) and laminarin prolongs the activation of the enzyme in a dose-dependent manner. However, injections of bacterial lipopolysaccharide (LPS) do not activate prophenoloxidase unless AKH is co-injected, when there is a dose-dependent increase in the level of phenoloxidase that persists in the haemolymph for several hours. Even when AKH is co-injected, the highest levels of phenoloxidase activity are always greater after injection of laminarin than after LPS, and these two immunogens must activate the prophenoloxidase cascade by quite distinct pathways. In the present study, interactions between the endocrine and immune systems were examined with respect to activation of prophenoloxidase and the formation of nodules: injection of LPS induces nodule formation in adult locusts. With LPS from Pseudomonas aeruginosa, nodules form exclusively in dense accumulations in the anterior portion of the abdomen on either side of the dorsal blood vessel associated with the dorsal diaphragm. However, with LPS from Escherichia coli, fewer nodules are formed but with a similar distribution, except that occasionally some nodules are aligned additionally on either side of the ventral nerve cord. Co-injection of Lom-AKH-I with LPS from either bacteria stimulates greater numbers of nodules to be formed. This effect of coinjection of AKH on nodule formation is seen at low doses of hormone with only 0.3 or 0.4 pmol of Lom-AKH-1, respectively, increasing the number of nodules by 50%. Injections of octopamine or 5-hydroxytryptamine do not mimic either of the actions of Lom-AKH-I described here. Co-injection of an angiotensin-converting enzyme inhibitor, captopril, reduces nodule formation in response to injections of LPS but has no effect on the activation of phenoloxidase. Co-injection of an inhibitor of eicosanoid synthesis, dexamethasone, with LPS influences nodule formation (with or without AKH) in different ways according to the dose of dexamethasone used, but does not affect activation of prophenoloxidase. Eicosanoid synthesis is important for nodule formation, but not for the activation of the prophenoloxidase cascade in locust haemolymph

    Demystifying cost misperception as a challenge to green building adoption in Nigeria

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    Purpose: The pertinent information about green buildings (GB) is laden with cost misperceptions (CM) that are paraded into adoption decisions without factual clarifications. The unsupported beliefs are fundamental to the disparaging low adoption of related technologies globally. The purpose of this paper is to explore the causes of CMs among construction stakeholders and why is it difficult to discredit this information? Design/methodology/approach: The research adopted two-tier approaches involving a Delphi study and a questionnaire survey. Construction stakeholders and GB experts, totalling 415 were surveyed, while 12 professionals participated in the Delphi study. This study analysed data from 254 valid responses using Factor Analysis, Fussy Set Theory and Kruskal Wallis test to explain why CMs are prevalent. Findings: The causes of CMs converge towards seven principal factors including low knowledge of GB practices, non-familiarity with performance metrics, inadequate evidence, poor-risk perceptions and reliance on the costs of exemplar projects. The results were explained using gaps in cost management, knowledge and sustainability accounting to show the critical improvements that can benefit GB adoption. Practical implications: CMs are not abstract but develop from patterns that can be detected and understood within a specific context. Growing GB projects within a region would improve cost information, sustainability accounting, cost management and quality of evidence. GB cost information paraded into adoption decision processes are overestimated and overvalued beliefs of their financial implications. Tackling the important sources of CMs in the study is appropriate to improve rational decision-making aiding GB adoption. Originality/value: This study untied causes of negative dispositions towards the cost of GB that distort stakeholders’ adoption decisions

    Is the selection of Ghanaian policy makers based on socio-cultural and ethnic reasonings relevant in today’s politics? Evidence from the Cape Coast Metropolis in Ghana

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    This study examines the effect of appraisive attitudes on citizens’ participation behaviour at the sub-national electoral levels in the Cape Coast Metropolis, Ghana. The study was quantitative with cross-sectional explanatory design. The study population was 1145 with a sample size of 291. The SPSS was employed for descriptive analysis and the Smart PLS was employed for structural equation modelling.  It was found that all the three dimensions of appraisive attitudes (policy responsiveness, performance and integrity) used in this study have positive effects on citizen participation behaviour in the study area of the Cape Coast Metropolis in Ghana. This means Africans have come of age and the days of choosing Africa policy makers based on socio-cultural and ethnic reasoning appear to be over. Policy makers must, therefore, take into consideration the interests of the citizens and work to improve on their living conditions in order to sustain their political career

    Detection of Weak D (Du) Phenotype among Rh-D Negative Males and Females in Kumasi, Ghana

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    Weak Rh D phenotypes are very frequent in Africans. They are capable of causing alloimmunization in Rh D-negative individuals. Some weak Ds may elude routine typing using direct agglutination techniques. This study aimed at determining the prevalence of weak D phenotype among Rhnegatives, using indirect antiglobulin technique. A total of 400 donors between the ages of 16 and 35 years who were grouped by the blood bank were randomly sampled over a period of 2 months. Three hundred and sixty nine (92.25%) were typed as Rh D-positive and 31 (7.75%) RhD-negative. Two (6.45%) of the Rh D-negative donors were weak D positive while 29 (93.55%) were weak D negative. Among the males 25 (9.43%) were Rh D-negative and 240 (90.57%) RhD-positive. Two (8%) of the 25 males were weak D positive. Among the females, 6 (4.44%) were Rh D-negative and 129 (95.56%) RhD- positive. This implies that, there are people in Kumasi with weak D phenotype which cannot be detected by the direct monoclonal anti-D agglutination. Consequently, indirect antiglobulin test may be indicated for such individuals typed Rh D-negative. This study has shown the need for a comprehensive policy on appropriate testing of donors and newborns, and management of Rh D-negative mothers in the Region. This should include weak D testing of all Rh Dnegative blood donors before transfusion in Rh D-negative patient. Keywords: Rhesus D, weak Rh D, indirect antiglobulin test, Kumasi-Ghana Journal of Science & Technology (Ghana) Vol. 28 (3) 2008: pp. 34-4

    An External Quality Assessment Of Haematology Laboratories-A Ghanaian Experience

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    Developed countries have guaranteed the quality of clinical laboratories through quality assurance programmes. However, these programmes have not received the needed attention in Ghanaian haematology laboratories, as is the case in many developing countries where visual counting of blood cells are the usual procedures. To assess the level of analytical quality of haematology laboratories in the Ashanti region of Ghana, form of an external quality assessment scheme was undertaken. The survey covered twelve haematology laboratories in both the public and the private sectors. Control blood samples were sent to the laboratories to be analyzed. The study, which lasted for five months, covered such routine haematological parameters as Hb, PCV, Total WBC and platelets. The results from these laboratories were compared to that of an automated cell counter using the Cell-Dyn 3700 (Abbot Diagnostic Division, USA). About 80% of the laboratories studied which were using the manual counting, achieved the medically accepted analytical performance for all the parameters except platelets, where the percentage of the laboratories dropped to about 70%. The study has established the need for a continuous internal and external quality assessment in haematology. Such practice together with continuous education of laboratory personnel and the provision of automated instruments will help to achieve optimum laboratory quality needed for proper health care delivery in the country. Keywords: External quality assessment, haematology laboratories, Ghana. Journal of Science and Technology Vol. 28 (1) 2008 pp. 17-2

    Assessment of the Potability of Underground Water from a Small Scale Underground Mine: A Case Study

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    This study sought to investigate the potability of underground water from the Mohammed and Brothers Small Scale Underground Mine in Tarkwa by analysing two samples of the underground water to determine the water’s physico-chemical parameters and the metals concentrations and coliforms in it. The physico-chemical parameters were analysed using Oyster series multi-meter (341350A) and Hydro test HT 1000 photometer. The result showed that the parameters were within the recommended World Health Organisation (WHO) and United States Environmental Protection Agency (USEPA) limits except for salinity and apparent colour. Analyses for metals and arsenic were conducted using the Varian Atomic Absorption Spectrometer (Varian ASS 240 FS). All the metals analysed were within the standards set by WHO and USEPA but the level of arsenic was above limit. The level of total coliforms and faecal coliforms were determined at the Intertek Service Limited, Tarkwa. The result showed that the levels were within the standards set by WHO and USEPA. The Water Quality Index (WQI) was calculated using the analysed water parameters. High levels of arsenic and salinity in the water renders it unsafe for drinking. Treatment of the water to reduce the arsenic and salinity levels to the standards set by WHO and USEPA will make it suitable for drinking and other domestic purposes. Keywords: Underground Water, Small Scale Underground Mining, Water Quality, Heavy Metals, Gol

    Promoting employee safety performance in the Chinese construction industry

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    In the construction industry, safety leadership has been widely recognised as an indispensable factor that affects organisational safety performance. However, in China specifically, research on safety leadership in the construction domain is not adequately developed. This paper examines the role of organisational leadership in promoting safety performance, as moderated by safety climate. The study adopts quantitative research method through questionnaire survey with 106 construction professionals leading or participating in safety management work in the Chinese construction sectors. The results show that exerting certain leadership strategies that encourage construction stakeholders to comply with safety practices will improve safety performance. At a moment when the whole industry is suffering from momentous safety challenges, transformation is required; these findings are intended to guide construction managers in their commitment to programme safety management. The study reinforces the interaction between upper layer and lower layer employees thereby improving the safety performance via improvements in the safety climate. In addition to being rooted in the full-range leadership model, this paper considered the impo rtant (and often ignored) characteristics of Chinese culture. The study recommends the early involvement of contractors in the design process and considers site hazards when making design decisions
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