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Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas
No full textThe goal of this investigation was to isolate competent polynuclear aromatic hydrocarbonsdegraders that can utilize polynuclear aromatic hydrocarbons of former industrial sitesat McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment methodbased on soil slurry, we isolated, screened and purified two bacterial species strains PB1 andPB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains wereassigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonassp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agarplates during the preliminary investigations. Using time course studies in the liquid culturesat calculated concentrations 123, 64, 97 and 94 ppm for naphthalene, chrysene, fluroantheneand pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilizationof the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicidastrain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developeda model R2= 1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, weconfirm that the former industrial site soil microbial communities may be explored for thebiorestoration of the industrial site
Review of parameter estimation techniques for time-varying autoregressive models of biomedical signals
Get PDFBiomedical signals are non-stationary and a research topic of practical interest as the signal has time varying statistics. The problem of time varying is usually circumvented by assuming local stationary over a short time interval, where stationary techniques are applied. However, features extracted from these methods are not always suitable and methods for non-stationary process are needed. Time varying signals are more accurately represented by time frequency methods and received most attention recently. Among the time frequency methods, parametric modeling such as TVAR has been promising over nonparametric methods with improved resolutions and able to trace strong non-stationary signal. Despite the success of TVAR in various applications it has drawbacks. This paper presents an extensive review on TVAR modelling techniques. Different approaches for TVAR modeling is presented and outlined. Principles, advantages, disadvantages of those techniques are presented concisely. And finally a new direction has been suggested briefly
USE OF SPECIAL COLLECTIONS BY POST GRADUATE STUDENTS IN SELECTED UNIVERSITIES IN SOUTH WEST, NIGERIA
No full textSecial collections are usually library materials selected.for specific purposes to meet specific needs. They are rare books and manuscripts which provide resources for the increasing needs of the research con11nunity in an academic or research institution. The study covers three universities in South-west Nigeria. 7hese universities are Lagos State University (LASU), Bowen University, fll'o, and Covenant university, Ota. One hundred and ninety-three respondents were sampled(or this study The descriptive si/ITey and stratified random sampling method was adopted.for this study. A structured questionnoire l1"US used to gather data .from the respondents. Data were analysed in tables using simple percentages and 111eun. The study showed that there is a high level o{utilization of special collections in the selected universities. The respondents, howeve1; pointed out poor bibliographic details of these special co/lee lions as a major hindrance to their easy accessibility and retrieval
In vitro antioxidant activities of African birch (Anogeissus leiocarpus) leaf and its effect on the α-amylase and α-glucosidase inhibitory properties of acarbose
Get PDFObjective
This study sought to determine the antioxidant activities of African birch leaf, to assess its interaction with key enzymes relevant to type 2 diabetes (α-amylase and α-glucosidase) and to evaluate its effect on acarbose in vitro.
Methods
One milligram per milliliter of aqueous extract of African birch and acarbose were separately prepared. At the same time, both the African extract and acarbose solution (50:50 v/v) were thoroughly mixed until homogeneity was attained. The phenolic phytoconstituents and antioxidant properties of African birch leaf were subsequently determined. Finally, the effects of African birch extract, acarbose solution and a mixture of acarbose and African birch extract on α-amylase and α-glucosidase activities were assessed in vitro.
Results
The results showed that African birch extract demonstrated a remarkable antioxidant effect, as exemplified by its radical scavenging abilities, Fe2+ chelating ability and prevention of lipid peroxidation. Acarbose had significantly (p < 0.05) higher α-amylase (IC50 = 11.77 μg/ml) and α-glucosidase (IC50 = 9.05 μg/ml) activities compared to African birch extract [α-amylase (IC50 = 242.17 μg/ml); α-glucosidase (IC50 = 196.35 μg/ml)]. However, the combination of acarbose and African birch extract showed an additive effect on α-amylase inhibition, while a resultant synergistic action was observed against α-glucosidase inhibition.
Conclusion
The additive and synergistic actions of the combination of African birch extract and acarbose solution suggest effective, complementary and alternative strategies towards the management/treatment of hyperglycaemia associated with type 2 diabetes
3-D Seismic Interpretation and Volumetric Estimation of “Osaja Field” Niger Delta, Nigeria
Get PDF3-D seismic interpretation and petrophysical analysis of the Osaja Field, Niger Delta, was carried out with aim of carrying out a detailed structural interpretation, reservoir characterization and volumetric estimation of the field. Four wells were correlated across the field to delineate the lithology and establish the continuity of reservoir sand as well as the general stratigraphy of the area. The petrophysical analysis carried out, revealed two sand units that are hydrocarbon bearing reservoirs (Sand_A and Sand_B).The spatial variation of the reservoirs were studied on a field wide scale using seismic interpretation. Time and depth structural maps generated were used to establish the structural architecture/geometry of the prospect area of the field. The depth structure map revealed NE-SW trending anticlinal structures with F5 and F6 as faults assisted closures to the reservoir. Furthermore, reservoir parameters such as net pay, water saturation porosity, net-to-gross etc, were derived from the integration of seismic and well log data. The structural interpretation on the 3-D seismic data of the study area revealed a total of seven faults ranging from synthetic to antithetic faults. The petrophysical analysis gave the porosity values of the reservoir Sand_A ranging from 18.1 - 20.3% and reservoir Sand_B ranging from 13.1-14.9% across the reservoir. The permeability values of reservoir Sand_A ranging from 63-540md and reservoir Sand_B ranging from 18-80md hence there is decrease in porosity and permeability of the field with depth.The net-to-gross varies from 22.1% to 22.4% in Rerservoir Sand A to between 5.34- 12% for Rerservoir Sand _A while Sw values for the reservoirs ranges from 38-42% in well 2 to about 68.79-96.06% in well 11. The result of original oil in place for all the wells calculated revealed that well 2 has the highest value with 9.3mmbls. These results indicate that the reservoirs under consideration have a poor to fair hydrocarbon (oil) prospect
The Bleak Nature Of Hrm Practices In Organisational Management Of Casual Labour Employments
Get PDFThe purpose of this study is to investigate the morbid use of numerical labour flexibility with a specific focus on
casual labour employment. Scholarly enquiries into labour casualization have often been assessed from a labourmarket flexibility perspective and/or managerial control of labour. In contrast, this research attempts to add to
literature by unveiling the experiences facing these organisational cohort from narrative accounts of employees. In
doing so, 20 interviews were conducted with casual staffs employed as security guards, cleaners and shelve
stackers at one of the Shoprite supermarket subsidiary operating in Nigeria. The findings exposed ebbing HR
practices regulating working conditions of these set of workers based on the low skill nature of their job roles.
Consequently, practical implications of the study proposes demands for HR managers to reconceptualise HRM
best practices that would accommodate and support casual labourers based on the rising need for firms to remain flexible in response to changing market vagaries
Traditionalism as a source of Change: Ola Rotimi’s Kurunmi as an epitome
Get PDFOla Rotimi’s Kurunmi has generally been classified as a
tragedy, historical play, postcolonial text, satire etc. Such general classifications have limited the analyses of the play to thematic thoughts such as cultural clash, postcolonial disillusionment, and its understanding as an emblem of
the Greek dramatic tradition. For this reason, this paper examines the issue of
traditionalism in the play centering on the faithfulness of the writer in utilizing
actual historical materials and personalities of the 19th century Yoruba war
between Ijaye and Ibadan armies (in Nigeria) and its implication on the general sensibility of the society. The paper examines the role of the major character of the play, Kurunmi, as a traditionalist and how his display of epic heroism helps produce resounding themes of socio-cultural relevance. It argues
that a conscious reading of the personalities, attributes, and egos of Kurunmi
as a traditionalist would make the reader have the privilege of having a real
sense of the complex nature of Kurunmi’s character rather than seeing him as
a prototype of a Greek tragic hero
Female youth in street trading: Implications for sexual harassment in HIV/AIDS risky environment
Get PDFThe study examined the exposure of young girls to street harassment in the urban centres of Nigeria and implications for the incidence of HIV/AIDS and economic empowerment. A ‘nonparticipatory direct observation approach coupled with quantitative secondary data was used. Quantitative data was extracted from a national survey of street traders sponsored by Covenant University, Nigeria. The survey covered sampled street traders in four major cities in Nigeria. However, only the data relating to young girls below the age of 25 years (n = 553) were extracted and analysed for this study. The study revealed that girls in younger ages (10-14 and 15-19 years) were 1.724 and 1.111 times more likely to be harassed compared to the other girls but self-employed girls enjoy ‘immunity’ from harassment because they have higher economic worth than their counterparts in paid or unpaid street trading activities. The study posits that exposure of girls to harassment increases the propensity for higher HIV/AIDS incidence in Nigeria and other sub-Saharan African countries. A proactive hawking measure should therefore be put in place to control the activities of the traders and enhance their full integration for effective economic empowerment of the girls and women in general
2016/10/13
No full textWhen using Information Retrieval (IR) systems, users often present search queries made of ad-hoc keywords. It is then up to the information retrieval systems (IRS) to obtain a precise representation of the user's information need and the context (preferences) of the information. To address this problem, we investigate optimization of IRS to individual information needs in order of relevance. The goal of this article is to develop algorithms that optimize the ranking of documents retrieved from IRS according to user search context. In particular, the ranking task that led the user to engage in information-seeking behaviour during search tasks. This article discusses and describes a Document Ranking Optimization (DROPT) algorithm for IR in an Internet-based or designated databases environment. Conversely, as the volume of information available online and in designated databases is growing continuously, ranking algorithms can play a major role in the context of search results. In this article, a DROPT technique for documents retrieved from a corpus is developed with respect to document index keywords and the query vectors. This is based on calculating the weight (w ij ) of keywords in the document index vector, calculated as a function of the frequency of a keyword k j across a document. The purpose of the DROPT technique is to reflect how human users can judge the context changes in IR result rankings according to information relevance. This article shows that it is possible for the DROPT technique to overcome some of the limitations of existing traditional (tf × idf) algorithms via adaptation. The empirical evaluation using metrics measures on the DROPT technique carried out through human user interaction shows improvement over the traditional relevance feedback technique to demonstrate improving IR effectiveness
Heat Transfer Analysis in Internal Combustion Engine Piston Using Comsol Multiphysics: A Case Study of Tri-Cycle
Get PDFThis present study is aimed at analyzing the heat transfer rate of an internal combustion engines piston using finite element methods (FEM).The transient nature of heat flowing involving more than single variable, complicated method of measuring temperature across the length of the liner and ambiguous boundary conditions pose serious problems for the analysis of heat transfer rate on the piston of an internal combustion engine using FEM (Finite Element Method). This present study analyzed the heat transfer rate on the piston of a Tri-cycle engine. The studied piston was selected based on its applications in automobile and other engineering applications. The analysis was basically on the transient state forced-convection and conduction heat transfer. As initial condition, the temperature distributions were considered along the piston at a range of 523K – 673K. The parameter used for the simulation were liquid (Gasoline), Gases (Air) and Aluminium silicon UNSA96061 (Piston). The modeling and simulation were performed by using COMSOL-Multiphysics 4.3a software. The mesh optimization was undertaken by using FEM techniques to predict the maximum and mimimum temperature on the piston at every stages of simulation with time dependent. It was discovered that the temperature along the piston of the try-cycle varies with respect to time. The transient analysis revealed that the temperature of the piston at the TDC (Top Dead Center) in the first power stroke is higher compare to the subsequent power strokes, which is an indication that more heat is transfer at subsequent power strokes. Probable recommendations were later made.Self-sponsore