Preliminary investigation of fish species abundance of Otammiri River, Owerri, Nigeria

A study of fish species abundance of Otammiri River, Owerri, Nigeria was conducted from April to August, 2012. Four hundred and three (403)fishes belonging to 10 families, 16 genera and 21 species were collected from artisanal fishers using various fishing gears. The fish samples were taken to laboratory, identified, counted and their weights and lengths measured. The unnamed cichlid species ranked highest in percentage number and weight as well as Index of Preponderance (38.7%, 33.6% and 51.1% respectively), while the least were Polycentropis abbreviata, Hepsetus odoe, Synodontis omias, Chrysichthys aluensis and Chrysichthys furcatus each constituting 0.2% of the total number of fish collected. Among fish families, Cichlidae ranked highest in percentage number (82.63%) and weight (81.2%), followed by Hepsetidae (5. 7% and 8.0%) and Anabantidae (4.47% and 2.8% respectively). The least were Characidae, Notopteridae and Mochokidae. The presence of an unnamed fish species in the river is an indication that there could be more unknown aquatic living resources with strong potential benefits to the River. The information provided in this study reflects the potential of the fish resources of Otammiri. This will serve as invaluable baseline tool in fisheries management planning and policy formulations that will enhance the development of fisheries in the area

Using humanoid robots to study human behavior

Our understanding of human behavior advances as our humanoid robotics work progresses-and vice versa. This team's work focuses on trajectory formation and planning, learning from demonstration, oculomotor control and interactive behaviors. They are programming robotic behavior based on how we humans “program” behavior in-or train-each other

Wear mechanism of olivine at the small-scale: An in situ TEM study

The study of tribology includes wear, friction, and lubrication of interacting surfaces in relative motions. Since the function, efficiency, and lifetime of many engineering components depend on the appropriate friction and wear properties, the study of tribology has significant practical importance. However, traditional tribology tests are limited by the inability to observe real-time progress of the sliding contacts and wear mechanism. Recent developments in small-scale devices, particularly piezoelectric and MEMS-based actuators, aid in conducting scratches at the micro- and nano-scale in the TEM. Olivine is magnesium iron silicate (Mg²⁺, Fe²⁺)₂SiO₄ and the most abundant mineral in earth\u27s upper mantle, which comprises the bulk of the planet\u27s tectonic plates. Although the structure of olivine has been intensively studied by mineralogists and geophysicists, the frictional and mechanical properties particularly damage evolution at the small-scale of sliding contact is unknown. In this study, a bulk olivine sample was wedge polished and then fib-milled to prepare electron-transparent regions. A wedge diamond indenter of 100 nm radius and 3 um length was used to make sliding contact using a PI 95, TEM PicoIndenter. Multicycle scratch tests were conducted to understand wear behavior. During the wear passes, the kinetic friction coefficient remained relatively constant near 0.1 and substantial dislocation plasticity occurred in the sample. Each pass showed nucleation of additional dislocations which were arranged in a symmetric array along the wear path as shown in fig. 1. The talk will present a theory of friction and deformation behavior that are applicable to geological materials. Please click Additional Files below to see the full abstract

A Study of HIV/AIDS Media Campaigns and Knowledge of High Risk Factors among Sex Workers in South-South Nigeria

The study investigates HIV/AIDS media campaigns and knowledge of high risk factors among sex workers in South-South geo-political zone of Nigeria. The main purpose of the study is to ascertain whether the numerous media campaigns on HIV/AIDS have positive influence on sex workers’ attitude towards the high risk factors of the pandemic.  In pursuance of this objective, the following questions were formulated to provide the needed guide to the study: Do media campaign messages on HIV/AIDS have a positive influence on respondents’ attitude towards penetrative sexual intercourse? Do respondents maintain consistent condom use with paying and non-paying clients? Would respondents shun sex without condom, irrespective of the amount the client would be willing to pay for it? Would respondents be willing to quit sex work knowing that it constitutes high risk behaviour of HIV/AIDS? Anchored on the agenda-setting theory and the standpoint theory, the work adopted survey method and utilised questionnaire as instrument of data collection. The sample size was 300 sex workers drawn purposively from three cities in South-South Nigeria, namely: Asaba, Port-Harcourt and Uyo. Findings of the study revealed that sex workers still engage in high risk behaviour of the scourge. The study, therefore, concluded that media campaigns on HIV/AIDS have not been effective on sex workers in the South-South geo-political zone of Nigeria. The paper recommends re-structuring of campaign strategies in order to make them more effective. Keywords: Sex Workers, HIV/AIDS, Media Campaigns, Knowledge and High Risk Factors

Characterization of Erbium-Doped Nanoparticles in Transparent Glass Ceramic Optical Fibres

We report on using nanometric mass spectroscopy and molecular dynamics modelling to characterize the composition and structure of self-grown erbium-doped nanoparticles in transparent glass ceramic optical fibres fabricated by modified chemical vapour deposition without post-ceramming

Investigation and evaluation of a 3D-printed optical modified cultivation vessel for improved scattered light measurement of biotechnologically relevant organisms

In the field of bioprocess development miniaturization, parallelization and flexibility play a key role reducing costs and time. To precisely meet these requirements, additive manufacturing (3D-printing) is an ideal technology. 3D-printing enables rapid prototyping and cost-effective fabrication of individually designed devices with complex geometries on demand. For successful bioprocess development, monitoring of process-relevant parameters, such as pH, dissolved oxygen (DO), and biomass, is crucial. Online monitoring is preferred as offline sampling is time-consuming and leads to loss of information. In this study, 3D-printed cultivation vessels with optical prisms are evaluated for the use in upstream processes of different industrially relevant microorganisms and cell lines. It was shown, that the 3D-printed optically modified well (OMW) is of benefit for a wide range of biotechnologically relevant microorganisms and even for mammalian suspension cells. Evaluation tests with Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae, and Chinese hamster ovary (CHO) cells were performed, providing highly reproducible results. Growth behavior of OMW cultures was comparable to behavior of shake flask (SF) cultivations and the signal to noise ratio in online biomass measurement was shown to be reduced up to 95.8% by using the OMW. Especially the cultivation phases with low turbidity respective optical densities below 1.0 rel.AU could be monitored accurately for the first time. Furthermore, it was demonstrated that the 3D-printed optics are transferable to different well geometries and sizes, enabling efficient biomass monitoring for individual requirements with tailor-made 3D-printed cultivation vessels in small scale

Sensors and Techniques for On-Line Determination of Cell Viability in Bioprocess Monitoring

In recent years, the bioprocessing industry has experienced significant growth and is increasingly emerging as an important economic sector. Here, efficient process management and constant control of cellular growth are essential. Good product quality and yield can only be guaranteed with high cell density and high viability. Whereas the on-line measurement of physical and chemical process parameters has been common practice for many years, the on-line determination of viability remains a challenge and few commercial on-line measurement methods have been developed to date for determining viability in industrial bioprocesses. Thus, numerous studies have recently been conducted to develop sensors for on-line viability estimation, especially in the field of optical spectroscopic sensors, which will be the focus of this review. Spectroscopic sensors are versatile, on-line and mostly non-invasive. Especially in combination with bioinformatic data analysis, they offer great potential for industrial application. Known as soft sensors, they usually enable simultaneous estimation of multiple biological variables besides viability to be obtained from the same set of measurement data. However, the majority of the presented sensors are still in the research stage, and only a few are already commercially available

Presentation and Preliminary Results of DROÏD Project: Development of a Distributed Optical Fibre Dosimeter

International audienceABSTRACT DROÏD project is intended to develop a distributed optical fibre dosimeter based on Radiation-Induced Attenua-tion (RIA). The RIA will be measured by a high resolution Optical Time Domain Reflectometry (OTDR) technique that allows to locate the irradiated fibre section. The first part of the project focuses on designing a high radiation sensitive fibre. As a preliminary work, the attenu-ation of several fibres with various compositions has been recorded in situ during and after irradiation. The experimental setup and RIA values are presented and discussed. Several dopants and their combinations have been identified as a good starting point to design a highly radiation sensitive fibre

Birefringence analysis of multilayer leaky cladding optical fibre

We analyse a multilayer leaky cladding (MLC) fibre using the finite element method and study the effect of the MLC on the bending loss and birefringence of two types of structures: (i) a circular core large-mode-area structure and (ii) an elliptical-small-core structure. In a large-mode-area structure, we verify that the multilayer leaky cladding strongly discriminates against higher order modes to achieve single-mode operation, the fibre shows negligible birefringence, and the bending loss of the fibre is low for bending radii larger than 10 cm. In the elliptical-small-core structure we show that the MLC reduces the birefringence of the fibre. This prevents the structure from becoming birefringent in case of any departures from circular geometry. The study should be useful in the designs of MLC fibres for various applications including high power amplifiers, gain flattening of fibre amplifiers and dispersion compensation.Comment: 18 page

Detection and phenotypic characterization of methicillin-resistant Staphylococcus aureus from clinical and community samples in Abakaliki, Ebonyi State, Nigeria

Objective: The objective of this study was to isolate and phenotypically characterize methicillin-resistant Staphylococcus aureus (MRSA)from clinical and community samples in Abakaliki, Nigeria.Methods: A total of 709 clinical (303) and community samples (406) samples were obtained for this study. MRSA isolates were detected using Kirby-Bauer disc diffusion method with the inclusion of 1 μg oxacillin and cefoxitin antibiotic disc. The isolates were screened for the β-lactamase production using nitrocefin sticks.Results: A total of 44 MRSA isolates were obtained from the samples with prevalence frequency of 22.6 % and 20.8 % from clinical and community samples respectively. The clinical isolates were completely resistant (100 %) to ceftazidime, tetracycline and penicillin. Gentamicin and ciprofloxacin were the most effective antibiotics against the clinical and community isolates respectively with a susceptibility frequency of 63.2 % and 80 %. Exactly 38.1 % and 24.2 % of the clinical and community S. aureus isolates were positive for beta-lactamase production respectively. The HA-MRSA and CA-MRSA isolates had MARI valueswithin the range of 0.3 to 1.0.Conclusion: This present findings of multi-drug resistance MRSA is very worrisome as it further highlights the pressing need to keep a strict watch on MRSA emerging from this study area.Keywords: MRSA, beta-lactamase, antibiotics, multidrug resistance, clinical samples, community samples