Cup anemometer response to the wind turbulence-measurement of the horizontal wind variance

International audienceThis paper presents some dynamic characteristics of an opto-electronic cup anemometer model in relation to its response to the wind turbulence. It is based on experimental data of the natural wind turbulence measured both by an ultrasonic anemometer and two samples of the mentioned cup anemometer. The distance constants of the latter devices measured in a wind tunnel are in good agreement with those determined by the spectral analysis method proposed in this study. In addition, the study shows that the linear compensation of the cup anemometer response, beyond the cutoff frequency, is limited to a given frequency, characteristic of the device. Beyond this frequency, the compensation effectiveness relies mainly on the wind characteristics, particularly the direction variability and the horizontal turbulence intensity. Finally, this study demonstrates the potential of fast cup anemometers to measure some turbulence parameters (like wind variance) with errors of the magnitude as those deriving from the mean speed measurements. This result proves that fast cup anemometers can be used to assess some turbulence parameters, especially for long-term measurements in severe climate conditions (icing, snowing or sandy storm weathers)

Impact of Competition on the Financial Performance of Listed Deposit Money Banks in Nigeria

The impact of bank competition on bank performance remains a widely debated issue. At present, scholars investigate either the competition-stability or the competition-fragility relationships. The traditional competition-fragility view equates bank competition with instability as competition reduces market power and profit margins which in turn encourages bank managers to take higher risks. In contrast, the competition-stability view stipulates that competition leads to lower loan interest rates and consequently lower moral hazard and adverse selection problems and less risky loan portfolios. This study examines both paradigms using panel data from deposit money banks in Nigeria over a period of ten years (2005-2014). Results show that the overall relationship between competition and financial performance of banks is negative. The study, therefore, concludes that competition has a negative effect on the financial performance of banks in Nigeria. The study suggests that regulators should promote healthy competition among deposit money banks so as to reduce the negative effect of competition on bank financial performance. Managers should take measures to enhance profit margin by reducing expenses. Current efforts of the government in terms of improved power generation may help to cut cost of power borne by the banks. Managers should also ensure healthy loan portfolio by ensuring that only customers with high credit scores get loans. Keywords: Bank, competition, financial performance, loan, market share, Nigeria, profit margin, risk.

Catalase activity of cassava (Manihot esculenta) plant under African cassava mosaic virus infection in Cape coast, Ghana

African cassava mosaic virus has caused an immersed low yield of the cassava crop. The virus impacts stress on the cellular metabolism of the plant producing a lot of reactive oxygen species and increases the expression of the antioxidant enzymes. The activity of catalase as a  response to oxidative stress was investigated in this research. Cassava leaf extract infected with the African cassava mosaic virus and uninfected were prepared and used as crude catalase extract. The total protein was  determined by Biuret method and activity of the crude catalase was  compared using hydrogen peroxide as substrate. Infected leaf extract had 141.02 ± 3.536 mg/mL protein, apparent Michealis constant (Kmapp) of 26.7 µM and maximum rate of reaction (Vmax) of 54.50 µM/min compared to the uninfected leaf extract with 75.04 ± 0.560 mg/mL protein, Kmapp of 39.61 µM and Vmax of 143.06 µM/min. The activation energy of the infected extract was 0.1578 J/mol compared to 0.2181 J/mol obtained for the  uninfected extract. Activity of the crude catalase in the viral infected leaf extract from the study was higher than that in the uninfected one and confirms the response to the stressful condition imposed by the viral infection.Key words: Cassava leaf extract, African cassava mosaic virus (ACMV), reactive oxygen species (ROS), catalase, hydrogen peroxide, Kmapp,  Vmax

Evaluation of the Efficacy of Plant Materials for the Control of Flea Beetles Podagrica spp on Okra Abelmoschus esculentus L

The efficacy of the Senegal prickly-ash Zanthoxylum zanthoxyloides (Lam.) roots and the African locust bean tree Parkia biglobosa (Jacq.) pod back was study for their efficacy in the control of okra pest, Podagrica spp. The study was carried out in the laboratory and on the field in the farming season of 2018. Z. zanthoxyloides roots were obtained from Jima-Doko forest and P. biglibosa fruit back from Takunpara. Both plant materials were air-dried under shade for 120 hours. Both plant parts were pounded separately in wooden mortar with the aid of wooden pestle until the materials turns to fine particles. Determined weight of 100, 150, 200, 250, and 300 grams were taken for each plant materials and soaked in water for 24 hours and stirred at intervals of an hour. The mixture were then sieved with a muslin cloth and filtered with Whatman filter paper to eliminate all finest particles of varying sizes. These concentrations were applied individually on 10 adults of Podagrica spp. in the laboratory. It was observed that the concentration of 200 – 300g performed better for both plant materials in the control of okra flea beetle. These resulted to the death of above 50% of the insect within 2 hours. These significant laboratory trials were then formulated and taken to the field. Both plant materials acted as anti-feedants and repellants against Podagrica spp. It was also revealed that Z. zanthoxyloides performed significantly (p<0.05) better than the P. biglibosa. Furthermore, short interval applications (<or=3days) of these plant materials could be a good  replacement for synthetic chemicals, hence bio-pesticides that could be adopted for organic agriculture

Turbulent characteristics of a semiarid atmospheric surface layer from cup anemometers – effects of soil tillage treatment (Northern Spain)

International audienceThis paper deals with the characteristics of turbulent flow over two agricultural plots with various tillage treatments in a fallow, semiarid area (Central Aragon, Spain). The main dynamic characteristics of the Atmospheric Surface Layer (ASL) measured over the experimental site (friction velocity, roughness length, etc.), and energy budget, have been presented previously (Frangi and Richard, 2000). The current study is based on experimental measurements performed with cup anemometers located in the vicinity of the ground at 5 different levels (from 0.25 to 4 m) and sampled at 1 Hz. It reveals that the horizontal wind variance, the Eulerian integral scales, the frequency range of turbulence and the turbulent kinetic energy dissipation rate are affected by the surface roughness. In the vicinity of the ground surface, the horizontal wind variance logarithmically increases with height, directly in relation to the friction velocity and the roughness length scale. It was found that the time integral scale (and subsequently the length integral scale) increased with the surface roughness and decreased with the anemometer height. These variations imply some shifts in the meteorological spectral gap and some variations of the spectral peak length scale. The turbulent energy dissipation rate, affected by the soil roughness, shows a z-less stratification behaviour under stable conditions. In addition to the characterization of the studied ASL, this paper intends to show which turbulence characteristics, and under what conditions, are accessible through the cup anemometer

BrdU Pulse Labelling In Vivo to Characterise Cell Proliferation during Regeneration and Repair following Injury to the Airway Wall in Sheep

The response of S-phase cells labelled with bromodeoxyuridine (BrdU) in sheep airways undergoing repair in response to endobronchial brush biopsy was investigated in this study. Separate sites within the airway tree of anaesthetised sheep were biopsied at intervals prior to pulse labelling with BrdU, which was administered one hour prior to euthanasia. Both brushed and spatially disparate unbrushed (control) sites were carefully mapped, dissected, and processed to facilitate histological analysis of BrdU labelling. Our study indicated that the number and location of BrdU-labelled cells varied according to the age of the repairing injury. There was little evidence of cell proliferation in either control airway tissues or airway tissues examined six hours after injury. However, by days 1 and 3, BrdU-labelled cells were increased in number in the airway wall, both at the damaged site and in the regions flanking either side of the injury. Thereafter, cell proliferative activity largely declined by day 7 after injury, when consistent evidence of remodelling in the airway wall could be appreciated. This study successfully demonstrated the effectiveness of in vivo pulse labelling in tracking cell proliferation during repair which has a potential value in exploring the therapeutic utility of stem cell approaches in relevant lung disease models

Fistulation and cannulation of goat single stage technique using locally improvised cannula

There is a great need presently for cannulation in small ruminants either for investigation of digestion as in evaluation of feed or collection of ruminal fluids, and this could be performed by many types of cannulae and techniques. The materials used here were fabricated (improvision) of cannula for goat and an adopted technique for its implantation. The device was adapted to allow sampling of entire ruminal contents via cannulae with similar diameters, which tightly sealed within ruminal fistula to ensure cleaner, achieve easier nursing of operated animals, and maintain normal ruminal environment. The device was applied into the goat by one-stage operation. It was successfully used in bucks for 10 months without complications in this experiment. Accordingly, this will encourage researchers to perform long-term studies of ruminal environment in small ruminants. Four indigenous breeds (Maradi) of goats were cannulated using an improvised cannula from local materials. One among these breeds was not fasted and water not withdrawn, but the other three were fasted for 24 hours and water withdrawn for 12 hours to minimize contamination by the ruminal content. The cannula was of 3cm in diameterweighing 78gms implanted to all the four. Aseptic measures were observed to prevent contamination and complication. Xylazine, diazepam and local aneasthetic (xylocaine) were used to sedate and desensitize the surgicalsite using inverted L block infiltration of the left flank. The one that was not fasted did not survive because of the high level of contamination from the ruminal content, but the three survived the surgery with one casualty of death due to poor management 48 hours post surgery. The remaining two survived without complication, thus, healing was by first intention, no leaking of ruminal content and suture was removed within 10 days post surgery. After four months post surgery one of the goats’ ruminal content started leaking at close observation. It was discovered to be due to  insertion of the left horn around the cannula which succeeded in widening the area leading to the leakage even though it was not copious

EDTA and nitric acid responses on nickel uptake, translocation factor and pigments on Spinacia oleracea L. replanted seedlings in hydroponic solution

The effects of Na2EDTA and HNO3 on Ni2+ uptake by Spinacia oleracea seedlings replanted inhydroponic culture in a greenhouse was investigated. Eight week old seedlings, were exposed to various doses of Ni2+ (0, 1000, 2000, and 4000 mg/L) as NiSO4, at (0, 500 and 3000 mg/L) Na2EDTA and ( 0, 500 and 3000 mg /L) HNO3 in different combinations. There was a substantial increase in nickel uptake in chelated treatments (p < 0.05) compared to unchelated treatments of same concentrations of Ni2+. So, chelation enhanced Ni2+ uptake in S. oleracea. During the exposure, antioxidant defense system helped the plant to protect itself from the damage. Due to increasing nickel  uptake by the plant, the photosynthetic pigments (i.e chlorophyll a, chlorophyll b and Caretenoids) gradually declined. In this study, Spinacia oleracea Seedlings and contents of the photosynthetic pigments (chlorophyll a, chlorophyll b and Caretenoids) of both chelated and unchelated hydroponic treatments were investigated. Changes in photosynthetic pigments was significant (p < 0.05) with respect to addition of EDTA and HNO3 at different concentration to different concentrations of Ni2+ compared to unchelated treatments of same concentrations of Ni2+. The Ni2+ induced translocation factor was also determined which increased significantly (P < 0.05) with increasing Ni2+ concentrations

Determination of Placement Distance of Fertilizer for Sugarcane as an Agronomic Requirement Relevant in the Design of a Fertilizer Applicator

Fertilizer placement distance at which sugarcane utilizes fertilizer optimally was determined in terms of its growth parameters (root distribution, stem height, stalk thickness, and leaf count). Three placement distances (4, 8 and 12 cm) were used as treatment and replicated four times. After subjecting the data obtained to Analysis of Variance (ANOVA) for Complete Randomized Design (CRD), the average means for a placement distance of 4 cm (for root distribution, stem height, stalk thickness and leaf count) are 3,910.75 cm 2 , 30.83 cm, 0.763 cm, and 9.5, while for 8 cm placement distance are 2,011.63 cm 2 , 27.70 cm, 0.699 cm, and 8.5. The values for 12 cm placement distance are 5,840.06 cm 2 , 34.55 cm, 0.788 cm and 11.25, respectively. These show that the effects of fertilizer placement distance on root distribution, stalk thickness and stem height are significant at 0.05 level of significance during three months of growth. It was highest at 12 cm placement and lowest was at 8 cm placement distance. Hence, fertilizer placement distance at 12 cm was recommended for the design and construction of a fertilizer applicator for sugarcan

Screening and identification of antibacterial agents produced by Aspergillus species from the soil of Bayero University Kano

This study was conducted to isolate antibiotic producing fungi in soil samples collected from Bayero University, Kano. Soil samples were suspended in deionised distilled water and inoculated on potato dextrose agar (PDA) by spread-plate method for the isolation of fungi. Primary screening of antibiotic producers was conducted using agar well diffusion method. All the isolates were identified to be in the genus Aspergillus. Out of the sixty (60) fungal isolates, three (3) species (A. flavus, A. fumigatus and A. niger) were selected for fermentation process and extraction of metabolites using ethyl acetate. The extracts were dried and subjected to disc diffusion assay against Streptococcus pneumoniae, Staphylococcus aureus, E. coli and Pseudomonas aeruginosa. The extracts showed inhibitory activity against all the test organisms at concentration of 1000μg and 800μg with little or no activity at 600μg against the tests organisms. Highest activity was observed from the metabolites of A. fumigatus on all the test organisms with MIC values of 250μg/ml. Thin layer chromatography of all the three extracts revealed four sports per chromatogram. The chromatogram study reveals many bioactive compounds such as Oleic acid, n-Hexadecanoic acid known to have antibacterial activity against range of bacteria. Similarly, the extracts showed some level of toxicity to brine shrimp. The extracts were found to have some pharmaceutical applications and therefore should be subjected for further bioassay such as anticancer and antioxidant.Keywords: Antibiotic producing fungi, Soil, Aspergillus, Oleic aci