Toxicological Impacts of Gas flaring and Other Petroleum Production Activities in Niger-Delta Environment

In this study, the concentrations of inducers of environmental toxicity such as heavy metals and polycyclic aromatic hydrocarbon and biomarkers of environmental toxicants such as oxidative stress enzymes/compounds and liver function enzymes were determined. These parameters were used to assess the pollution status of some Niger-Delta areas; Ebocha/Omoku, Abacheke/Egbema, and Okwuzi/Ohaji, with the aid of two indicator species: cat fish (Ictalurus punctatus) and snakehead fish (Channa argus) from three different water sources; Ebocha/Omoku river, Abacheke river and Okwuzi creek all of which are within the area of oil exploration and production activities in Nigeria. The control fish and water samples were collected from Otamiri River within the Federal University of Technology, Owerri, Nigeria, with no known oil exploration and production activity. The results obtained indicated significant (p < 0.05) differences between the exploited and the unexploited environment and the need to incorporate biochemical markers in environmental impact assessment of aquatic environments to complements the classical chemical monitoring.Â

Lead-induced Oxidative Stress and Chemoprotective Role of Dietary Supplements on Wistar Albino Rats

The heavy metal lead (Pb) is a common environmental pollutant with widespread distribution, and oxidative stress has been implicated in the pathogenesis of its toxicity. The ameliorative effect of nutritional contents of palm oil and cod liver oil (dietary supplements) following exposure to sublethal concentration of Pb on adult Wistar albino rats was studied. Toxicity was induced by administering intraperitoneally, 30 mg/kg body weight of lead acetate at alternate days for 21 days. Groups treated with supplements received daily oral dose of 2.5 ml palm oil or cod liver oil or 1.25 ml palm oil and 1.25 ml cod liver oil (synergy). Increased activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, decreased activities of superoxide dismutase, catalase, glutathione peroxidase and increased concentrations of total bilirubin and lipid peroxidation product were observed in Pb exposed rats without nutritional supplement treatment. However, these negative oxidative states were ameliorated in rats by the concomitant administration of nutritional supplements, singly and in combination. Furthermore, non-significant changes were observed in the haematological parameters determined. These observations indicate potential therapeutic benefits in the use of palm oil and cod liver oil in the management of lead-induced toxicity

A fruit diet rather than invertebrate diet maintains a robust innate immunity in an omnivorous tropical songbird

Experiments were funded by the Royal Netherlands Academy of Arts and Sciences (KNAW) Academy Ecology Fund to C.J.N—(KENMERK J1618/ECO/G437). C.J.N. was supported by a studentship funded by the Leventis Conservation Foundation through the University of St. Andrews UK and an Ubbo Emmius grant of the University of Groningen, The Netherlands. B.I.T. was supported by the Netherlands Organisation for Scientific Research (NWO‐Vidi 864.10.012).1. Diet alteration may lead to nutrient limitations even in the absence of food limitation, and this may affect physiological functions, including immunity. Nutrient limitations may also affect the maintenance of body mass and key life history events that may affect immune function. Yet, variation in immune function is largely attributed to energetic trade-offs rather than specific nutrient constraints. 2. To test the effect of diet on life history traits, we tested how diet composition affects innate immune function, body mass and moult separately and in combination with each other, and then used path analyses to generate hypotheses about the mechanistic connections between immunity and body mass under different diet composition. 3. We performed a balanced parallel and crossover design experiment with omnivorous common bulbuls Pycnonotus barbatus in out-door aviaries in Nigeria. We fed 40 wild-caught bulbuls ad libitum on fruits or invertebrates for 24 weeks, switching half of each group between treatments after 12 weeks. We assessed innate immune indices (haptoglobin, nitric oxide and ovotransferrin concentrations, and haemagglutination and haemolysis titres), body mass and primary moult, fortnightly. We simplified immune indices into three principal components (PCs), but we explored mechanistic connections between diet, body mass and each immune index separately. 4. Fruit fed bulbuls had higher body mass, earlier moult and showed higher values for two of the three immune PCs compared to invertebrate fed bulbuls. These effects were reversed when we switched bulbuls between treatments after 12 weeks. Exploring the correlations between immune function, body mass and moult, showed that an increase in immune function was associated with a decrease in body mass and delayed moult in invertebrate fed bulbuls, while fruit fed bulbuls maintained body mass despite variation in immune function. Path analyses indicated that diet composition was most likely to affect body mass and immune indices directly and independently from each other. Only haptoglobin concentration was indirectly linked to diet composition via body mass. 5. We demonstrated a causal effect of diet composition on innate immune function, body mass and moult: bulbuls were in better condition when fed on fruits than invertebrates, confirming that innate immunity is nutrient specific. Our results are unique because they show a reversible effect of diet composition on wild adult birds whose immune systems are presumably fully developed and adapted to wild conditions – demonstrating a short-term consequence of diet alteration on life history traits.Publisher PDFPeer reviewe

Safeguarding human–wildlife cooperation

Human–wildlife cooperation occurs when humans and free-living wild animals actively coordinate their behavior to achieve a mutually beneficial outcome. These interactions provide important benefits to both the human and wildlife communities involved, have wider impacts on the local ecosystem, and represent a unique intersection of human and animal cultures. The remaining active forms are human–honeyguide and human–dolphin cooperation, but these are at risk of joining several inactive forms (including human–wolf and human–orca cooperation). Human–wildlife cooperation faces a unique set of conservation challenges, as it requires multiple components—a motivated human and wildlife partner, a suitable environment, and compatible interspecies knowledge—which face threats from ecological and cultural changes. To safeguard human–wildlife cooperation, we recommend: (i) establishing ethically sound conservation strategies together with the participating human communities; (ii) conserving opportunities for human and wildlife participation; (iii) protecting suitable environments; (iv) facilitating cultural transmission of traditional knowledge; (v) accessibly archiving Indigenous and scientific knowledge; and (vi) conducting long-term empirical studies to better understand these interactions and identify threats. Tailored safeguarding plans are therefore necessary to protect these diverse and irreplaceable interactions. Broadly, our review highlights that efforts to conserve biological and cultural diversity should carefully consider interactions between human and animal cultures. Please see AfricanHoneyguides.com/abstract-translations for Kiswahili and Portuguese translations of the abstract

Safeguarding human–wildlife cooperation

Human–wildlife cooperation occurs when humans and free-living wild animals actively coordinate their behavior to achieve a mutually beneficial outcome. These interactions provide important benefits to both the human and wildlife communities involved, have wider impacts on the local ecosystem, and represent a unique intersection of human and animal cultures. The remaining active forms are human–honeyguide and human–dolphin cooperation, but these are at risk of joining several inactive forms (including human–wolf and human–orca cooperation). Human–wildlife cooperation faces a unique set of conservation challenges, as it requires multiple components—a motivated human and wildlife partner, a suitable environment, and compatible interspecies knowledge—which face threats from ecological and cultural changes. To safeguard human–wildlife cooperation, we recommend: (i) establishing ethically sound conservation strategies together with the participating human communities; (ii) conserving opportunities for human and wildlife participation; (iii) protecting suitable environments; (iv) facilitating cultural transmission of traditional knowledge; (v) accessibly archiving Indigenous and scientific knowledge; and (vi) conducting long-term empirical studies to better understand these interactions and identify threats. Tailored safeguarding plans are therefore necessary to protect these diverse and irreplaceable interactions. Broadly, our review highlights that efforts to conserve biological and cultural diversity should carefully consider interactions between human and animal cultures

Nutritional and toxicological composition of Argemone americana Lin leaves

No Abstract. IJOTAFS Vol. 1 (2) 2007: pp. 106-10

AC-DC Solid-State Conversion and Power Factor Correction using Thyristor-Based Static Var Compensator

This paper presents AC-DC solid states converters with thyristor-based static Var compensator in power factor correction. There is need for solid-state ac–dc converters to improve power quality in terms of power factor correction, reduce total harmonic distortion at input ac mains and precisely regulate dc output. AC-DC converters operating in continuous-conduction mode have become popular because of reduced electromagnetic interference levels resulting from their utilization. The method employs the principle of interleaved converters, as it can be extended to a generic number of legs per winding of the autotransformers and high-power levels. The practical analysis of the converter is then plotted using a Simulink model of Matlab while a comparison of power factor and efficiency with relative to the load is drawn with Steady-State and Dynamic Performance of the Static Var Compensator (SVC). An experimental prototype load varied between 400W to 1 KW is implemented to validate the work. The results obtained indicates that when the output loads were 53KW, 135KW, 270KW, 470KW and 900KW, the efficiency were 55%, 70%, 80%, 90% and 97% respectively. These results confirmed that there was improvement in the power factor and efficiency with increase in the load

Ocular morphology of the fruit bat, Eidolon helvum, and the optical role of the choroidal papillae in the megachiropteran eye: a novel insight

Background: This work was designed to provide a morphologic, morphometric and histochemical description of the eye of the African straw-coloured fruit bat (Eidolon helvum). An explanation of the optical role of the choroidal papillae in the vision of megachiropteran bats was provided. Materials and methods: Enucleated eyes of captured fruit bats were measured and processed for light microscopy. Results: Typical gross features of the mammalian eye including an anterior transparent cornea, posterior whitish sclera and a golden-brown iris surrounding a round pupil were observed in the eye. Presence of undulating retina typically found in megachiropterans were also seen. The ratio of mean corneal diameter to mean axial eye diameter was 0.58 ± 0.08. The histochemical investigation of the eye indicated the presence of mucins, proteoglycans, hyaluronic acid, glycogen and/or glycoproteins in the corneal, scleral, choroidal and retinal tissues. Conclusions: The presence of reflective materials of the tapetum lucidum on the undulating retina was shown to be a morphological adaptation for increased light sensitivity as each parabolic surface of the choroidal papillae served as a convex mirror, reflecting the light rays to the adjacent parabolic surface, thus sensitizing photoreceptors in affected regions. This phenomenon thus empowers megachiropteran bats with improved scotopic visual capability and could explain why most of them are reliant on their vison without the need for echolocation