The dynamics of a self-phoretic Janus swimmer near a wall

We study the effect of a nearby planar wall on the propulsion of a phoretic Janus micro-swimmer driven by asymmetric reactions on its surface which absorb reactants and generate products. We show that the behaviour of these swimmers near a wall can be classified ${\bf based \ on \ whether}$ the swimmers are ${\bf mainly}$ absorbing or producing reaction solutes ${\bf and \ whether}$ their swimming directions are such that the inert or active face is at the front. We find that the wall-induced solute gradients always promote swimmer propulsion along the wall while the effect of hydrodynamics leads to re-orientation of the swimming direction away from the wall.Comment: 6 pages, 6 figure

Optimization of RBF-SVM hyperparameters using genetic algorithm for face recognit

Manual grid-search tuning of machine learning hyperparameters is very time-consuming. Hence, to curb this problem, we propose the use of a genetic algorithm (GA) for the selection of optimal radial-basis-function based support vector machine (RBF-SVM) hyperparameters; regularization parameter C and cost-factor γ. The resulting optimal parameters were used during the training of face recognition models. To train the models, we independently extracted features from the ORL face image dataset using local binary patterns (handcrafted) and deep learning architectures (pretrained variants of VGGNet). The resulting features were passed as input to either linear-SVM or optimized RBF-SVM. The results show that the models from optimized RBFSVM combined with deep learning or hand-crafted features yielded performances that surpass models obtained from Linear-SVM combined with the aforementioned features in most of the data splits. The study demonstrated that it is profitable to optimize the hyperparameters of an SVM to obtain the best classification performance. Keywords: Face Recognition, Feature Extraction, Local Binary Patterns, Transfer Learning, Genetic Algorithm and Support Vector  Machines

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

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

Control Environment and Internal Control System Effectiveness of Listed Deposit Money Banks in Nigeria

This study examines the effect of control environment on internal control system effectiveness of listed deposit money banks in Nigeria. Primary data were collected using the 5-point Likert scale structured questionnaire adopted from the Committee of Sponsoring Organizations of the Treadway Commission(COSO, 1992) on internal control system effectiveness. A total of five hundred and forty (540)sets of questionnaire were sent out and four hundred and thirty-five (435) received representing about eighty-one(81%) percent response rate: also resulting in four hundred and thirty-five observations. The data were diagnosed for normality, heteroskedasticity and reliability (internal consistency) tests. Data were analyzed using descriptive statistics (mean, standard deviation, minimum and maximum) and inferential statistics (correlation and simple regression analysis). Results show that control environment has a positive and significant effect on internal control system effectiveness of listed deposit money banks in Nigeria. The study, therefore concludes that control environment (measured by integrity of senior management) has a significant and positive effect on ICSE of listed deposit money banks in Nigeria. Based on this conclusion, the study recommends that managers of listed deposit money banks should continue to strengthen integrity in the workplace, and maintain a positive disposition towards the control environment of their banks

Effects of Phosphorus and Rhizobium Inoculation on Yield Components and Grain Yield of Some Selected Cowpea Genotypes

The effects of phosphorus (0, 20, 40kg P2O5ha-1) and rhizobium inoculation (inoculated and un-inoculated) on the yield components and grain yield of three cowpea genotypes (IT93K-452-1, IT97K-573-1-1 and IT98K-499-35) were investigated under field conditions at Bayero University, Kano, Teaching and Research Farm (11059 N; 8025 E; 466m above sea level) and Agricultural Research Station Farm, Minjibir (12010’ N,  8039’ E; 402m  above sea level) in 2014 rainy season. Cowpea genotypes were assigned to the main plot, while phosphorus levels were assigned to the sub-plots. The inoculation was assigned to the sub-sub plot. These were laid out in Split-split plot design and replicated three times. Results of the study indicated significant effect of genotype in all the characters measured except shelling percent. Significantly (p˂ 0.05) higher number of pods per plant, pod weight, fodder and grain yield was observed from IT99K-573-1-1 than all other genotypes evaluated. Similarly, the number of pods per plant, pod weight, fodder and grain yield were significantly influenced by application of phosphorus with better results recorded from 40 kg P2O5 treated plants. Inoculation of cowpea with rhizobium MC92 strain, also recorded significant effect on the measured characters and grain yield. Inoculation of cowpea with rhizobium MC92 along with 40kgP2O5 ha-1 could enhance performance of cowpea particularly with an adaptable genotype like IT99K-573-1-1. Keywords: Cowpea, grain yield, inoculation, yield component

Preparation and characterization of a poly-herbal tea with effective antioxidant properties

Many herbal teas consist of poly-herbal materials that are often folk recipes with known health benefits. Poly-herbal teas containing the leaves of Moringa oleifera, Zingiber officinale and juice of Citrus limon were developed and evaluated for its physicochemical and stability properties. The herbal tea generally showed good physicochemical properties such as organoleptic properties, excellent flow, optimal ash value and moisture content. It showed stability properties that are characteristic of a good finished herbal product. The tea also showed effective free radical scavenging properties similar to that of ascorbic acid and consistent with its antioxidant benefits. Some of its physicochemical and antioxidant properties were diminished when stored in a stress environment. Formulating the poly-herbal recipe of M. oleifera, Z. officinale and juice of C. limon into herbal tea is an effective means of presenting the herbal medicine for use

Fungi Causing Post-Harvest Spoilage Carica papaya Linn Fruits of Two Selected Markets in Kano State, Nigeria

This study was carried out for four month (September, 2015 to December, 2015) to find the fungal species associated with post-harvest spoilage of pawpaw fruits sales at Na’ibawa and Wudil Markets all in Kano State. A total of five strains of fungi were isolated and identified as Aspergillus niger, Aspergillus flavuus, Rhizophus stolonifer, Yeast, and Fusarium. Pathogenicity test of each fungal isolate showed that all fungi were capable of causing rotting of the fruit and most severe rotting was caused by Aspergillus niger and Yeast with 8(29.63%) Respectively at Na’ibawa market and 10(34.48%) and 9(31.03%) at Wudil market followed by Rhizophus with 7(25.93%) and 5 (17.25%) while Aspergillus flavus and Fusarium produced the least rotting of the fruit. The difference in the fungal spoilage of Carica papaya between the two market areas Na’ibawa and Wudil markets was statistically significant (p≥0.05). From the result of this study, it is clearly indicated that the spoilage of pawpaw fruits in the two markets was due to fungal attack

A trend analysis and sub-regional distribution in number of people living with HIV and dying with TB in Africa, 1991 to 2006

<p>Abstract</p> <p>Background</p> <p>The tuberculosis (TB) bacillus and the Human Immunodeficiency Virus (HIV) have formed a powerful alliance and are together responsible for more than five million deaths per year. TB is leading to increased mortality rates among people living with HIV/acquired immunodeficiency syndrome (AIDS). The aim of this study was to investigate the geographical and temporal distribution of TB-HIV deaths in Africa in order to identify possible high-risk areas.</p> <p>Methods</p> <p>Time trends in the 16-year study period from 1990 to 2005 were analyzed by multilevel Poisson growth curve models. Moran global and local indicators of spatial associations were used to test for evidence of global and local spatial clustering respectively.</p> <p>Results</p> <p>Eastern, Southern, Western, and Middle Africa experienced an upward trend in the number of reported TB-HIV deaths. The spatial distribution of TB cases was non-random and clustered, with a Moran's I = 0.454 (p = .001). Spatial clustering suggested that 13 countries were at increased risk of TB-HIV deaths, and six countries could be grouped as "hot spots".</p> <p>Conclusion</p> <p>Evidence shows that there is no decline in growth in the number of deaths due to TB among HIV positive in most Africa countries. There is presence of 'hot-spots' and very large differences persist between sub-regions. Only by tackling TB and HIV together will progress be made in reversing the burden of both diseases. There is a great need for scale-up of preventive interventions such as the World Health Organization '3I's strategy' (intensified case finding, isoniazid preventive therapy and infection control).</p