Effect of Size on the Acute Toxicity of Crude Oil to the Mangrove Oyster, Carasostrea gasar

The acute toxic effects of a Nigerian crude oil (Egbogoro Liner II) to the mangrove oyster Carasostrea gasar were studied in bioassays. Tests were conducted over a 96-hr period after acclimatization of individuals in the laboratory, initially with a population comprising a broad size categories (11 - 60 mm) in range finding tests. The tests were semi-static bioassays in which the exposure media were replaced every 24 hours, at which the oysters were also examined for mortality. Subsequent experimentation was designed to compare the toxicities of oil to small (10 - 30 mm) and large (41 - 60 mm) oysters. LC50 values were obtained by graphical interpolation. Significant differences in effects at each time interval between small and large oysters were determined using the Man-Whitney tests on percentage mortality values. Relative toxicity tests showed consistently lower mortalities for small oysters at 24-hr, 48-hr and 96-hr periods, with Mann-Withney tests showing significant differences (p<0.05) in mortality in 48 and 96 hr bioassays. The 96-hr LC50 value for the larger oysters (135 ppm) was lower than that of the smaller ones (545 ppm), implying that smaller oysters (in the size ranges used) were more tolerant to crude oil than the larger ones. @JASE

Effect of Diazinon on Acid and Alkaline Phosphatase Activities in Plasma and Organs of Clarias gariepinus

Abstract: The aim of this study was to determine the effect of the pesticide, diazinon, on phosphatases in the plasma and organs on Clarias gariepinus. Adult Clarias gariepinus were exposed in four replicates to varying sublethal concentrations diazinon (ranging from 1.00 to 10.0 mg/L) in 30-day semi-static bioassays. Alkaline phoshatase (ALP) and acid phosphate (ACP) were determined in plasma and other organs (gastrointestinal tract -GIT, kidney, muscle, gill and liver) of the fish after the experimental exposures. Dizinon did not cause any statistically significant difference on plasma ALP over the concentrations tested (p>0.05), but ACP showed significantly higher mean value at 10 mg/L compared to the control. ALP and ACP values in all the organs (GIT, intestinal tract, kidney, muscle, gill, liver) decreased with increasing concentration of diazion. This indicates an evidence of inhibition of these enzymes in the organs by the toxicant, and therefore alteration of biochemical processes in C. gariepinus which can be used as bio-indicators of the effects of diazinon in the Niger Delta environment

Controller design for model-scale rotors and validation using prescribed motion

Aerodynamic-load calculation in aero-hydro-servo-elastic modeling tools has been recently validated against experiments for low-frequency platform motions but without considering the capability of active wind turbine controls. This work presents a control design framework that allows for including industry-standard wind turbine control functionalities in a model-scale rotor and its application to a 1:100 scaled version of the International Energy Agency (IEA) 15 MW turbine. Wind tunnel tests with a fixed foundation and steady wind show the scaled turbine reproduces the steady-state rotor speed–blade pitch–thrust–torque characteristics of the IEA 15 MW turbine, confirming the controller design method. Tests with a prescribed platform pitch motion are carried out to assess the turbine response and controller modeling in conditions representative of the normal operation of floating wind turbines. The blade element momentum model of OpenFAST is verified against the experiment, showing aerodynamic thrust and torque are predicted with higher accuracy in the below-rated than the above-rated region: in our simulation, the decrease in thrust oscillation amplitude due to blade pitch actuation is underpredicted. This, combined with uncertainty in modeling the blade pitch actuators, complicates the numerical–experimental simulation of the turbine aerodynamic response in above-rated operation.</p

Effect of Size on the Acute Toxicity of Crude Oil to the Mangrove Oyster, Carasostrea gasar

The acute toxic effects of a Nigerian crude oil (Egbogoro Liner II) to the mangrove oyster Carasostrea gasar were studied in bioassays. Tests were conducted over a 96-hr period after acclimatization of individuals in the laboratory, initially with a population comprising a broad size categories (11 - 60 mm) in range finding tests. The tests were semi-static bioassays in which the exposure media were replaced every 24 hours, at which the oysters were also examined for mortality. Subsequent experimentation was designed to compare the toxicities of oil to small (10 - 30 mm) and large (41 - 60 mm) oysters. LC50 values were obtained by graphical interpolation. Significant differences in effects at each time interval between small and large oysters were determined using the Man-Whitney tests on percentage mortality values. Relative toxicity tests showed consistently lower mortalities for small oysters at 24-hr, 48-hr and 96-hr periods, with Mann-Withney tests showing significant differences (

The Effects of Caging on the Colonization of Fouling Organisms in the Upper Bonny Estuary

The effects of caging on the colonization and development of the fouling community in the upper Bonny estuary was studied. The experimental design was such that sets of wooden panels (20x20 cm) were screened with cages constructed with plastic netting while another set was left uncaged. Both sets of panels were submerged below low tide level and sampled fortnightly for seventy-four days. The species settling on the panels (as well as on the mesh of the cage) were identified and examined for percentage cover. Data obtained were subjected to Analyis of Variance or t-tests after arc-sine transformation. Faunal abundance was found to be significantly higher on the mesh of the cage than on the panels (p<0.001). Differences between the caged and uncaged panels were influenced by time as total cover was found to decline with time on the caged panels. Pennaria distichia, Styela sp. and Sabella sp. achieved significantly higher cover on the mesh of the cage than the panels (p<0.001). Some species that settled on the panels (Balanus sp., Membranipora membranacea, Serpula sp, Halichondria sp, Crassostrea gasar) were not found on the mesh of the cage, and both Balanus and M. membranacea showed significantly higher abundance on uncaged panels (p<0.05). Current speed and sedimentation may have accounted for much of the difference in settlement between cagaed and uncaged panels. @ JASE

An Estimation of the Potential Prevalence of "Syndrome X" amongst Diabetics Using Traditional Markers

In order to estimate the potential prevalence of "Syndrome X" in newly diagnosed cases of insulinoplethoric diabetes mellitus, patients were selected from the emergency (accident) ward, University of Benin Teaching Hospital, Benin City, Nigeria. Both risk factors (plasma lipids) and allied metabolic aberration (plasma glucose and creatinine) were assessed in 100 subjects comprising of 60 patients (30 males, 30 females) within the ages of 35 to 70 years and 40 sex and age matched healthy control subjects. Results showed significant increase in patients mean plasma glucose, tricyglycerol and total cholesterol when compared with the respective mean control values at the 5% probability level, using ANOVA. Their lipoprotein-cholesterol profile also, showed a significant difference (

Effect of sustainable poultry interventions on household food security and resilience in game management areas of Zambia's Luangwa Valley: a before-and-after study

Background: Zambia's Luangwa Valley epitomises the linked environmental, agricultural, and human health problems around protected wildlife areas in developing countries. Smallholder crop yields are usually poor, and farmers turn to the unsustainable harvesting of natural resources, including hunting, fishing, and deforestation for charcoal production to supplement household income and food supply. Chronic poverty and food insecurity are pervasive and long-term household and environmental resilience are uncertain. Village poultry can ameliorate these problems, through the provision of animal-source food and income and an alternative to consumption of natural resources. However, the returns on traditional backyard poultry ownership are reduced by high flock losses and poor flock genetics. We, therefore, designed and implemented two poultry interventions and measured their effect on productivity, profitability, and consumption of animal-source food. Methods: We implemented two programmes in the Luangwa Valley, Zambia. First, we undertook a community vaccination programme for Newcastle disease virus (NDV) in village chickens in Mambwe and Lundazi districts and gave flock owners instruction in improved management practices through workshops. We recorded changes in flock size over 4 years, using surveys administered every 4 months, and we used other primary and secondary data sources to assess changes in poultry-related income and chicken and egg consumption. For the second programme, we facilitated construction of semi-intensive egg production facilities in 24 communities. Layer-hen facilities each held 40 hens and were owned and operated by a group of 4–5 people. We recorded data on egg productivity (the number of eggs produced on a day divided by the number of hens in the flock on that day), poultry-related income, and egg consumption for 1 year using facility records, a semiannual survey, and qualitative interviews. Findings: In areas covered by the NDV vaccine programme, mean household flock size increased from 10·9 birds in July, 2007, to 25·7 birds in November, 2011 (p<0·0001). Mean annual income from poultry increased 138%, from US$16·89 to US$ 40·25, annually. Chicken and egg consumption was unchanged over the study period, reflecting farmers' preference to sell birds. Where new semi-intensive egg production facilities were introduced, mean egg productivity was 62·5% during the first 9 months between September, 2015, and May, 2016, and mean group net income was US$30·28 per month. Some groups used this income to invest in other businesses, together or individually, while others used it during the so-called hungry season to buy maize for their own households. Although most eggs were sold, weekly egg consumption increased 118% in producer households (from 3·3 to 7·2 eggs per week), including 167% in women (from 0·9 to 2·4 eggs per week) and 263% in young children ages 6 to 36 months (from 0·8 to 2·9 eggs per week). Interpretation: NDV vaccination and improved management sustainably increased flock sizes and improved household income but had no direct effect on household consumption of animal-source food. By contrast, semi-intensive egg production businesses provided both consistent income and significant increases in consumption of animal-source food, not only promoting food security and resilience but also providing a potentially important alternative to bushmeat in villages surrounding ecologically-important protected areas. Funding: Atkinson Center for a Sustainable Future (AJT) and the National Institutes of Health (T32 OD011000, SED)