EUSpace
Not a member yet
791 research outputs found
Sort by
Analysis of transient multiexponential signals using cepstral deconvolution
Get PDFWe propose and test a new method of multiexponential transient signal analysis. The method based on cepstral deconvolution is fast and computationally inexpensive. The multiexponential signal is initially converted to a deconvolution model using Gardners' transformation after which the proposed method is used to deconvolve the data. Simulation and experimental results indicate that this method is good for determining the number of components but performs poorly in accurately estimating the decay rates. Influence of noise is not considered in this paper
Vascular intersection detection in retina fundus images using a new hybrid approach
Get PDFThe use of vascular intersection aberration as one of the signs when monitoring and diagnosing diabetic retinopathy from retina fundus images (FIs) has been widely reported in the literature. In this paper, a new hybrid approach called the combined cross-point number (CCN) method able to detect the vascular bifurcation and intersection points in FIs is proposed. The CCN method makes use of two vascular intersection detection techniques, namely the modified cross-point number (MCN) method and the simple cross-point number (SCN) method. Our proposed approach was tested on images obtained from two different and publicly available fundus image databases. The results show a very high precision, accuracy, sensitivity and low false rate in detecting both bifurcation and crossover points compared with both the MCN and the SCN method
Acute administration of co-artesiane induces oxidative stress in the testes of adult male Wistar rats
Get PDFCo-artesiane is an artemether-lumefantrine combination therapy that is used in the treatment of malaria. In this work we studied the toxicological effect of this drug with reference to seminal and biochemical parameters of the male reproductive system of wistar rats. Twenty (20) adult male rats were divided into four groups of five rats per group. Group A was administered a single dose (4 mg/kg/bw) of Co-artesiane, Group B was administered double dose (8 mg/kg/bw) of Co-artesiane and Group C received 10 mg/kg/bw of the drug for a period of 3 days. Group D served as control and received physiologic saline. In each group body weight, testicular weight, sperm count, motility and viability as well as oxidative stress status were assessed by evaluating the activities of reduced glutathione, Glutathione S-transferase, catalase, super oxide dismutase (SOD) and malondialdehyde (MDA). The mean sperm count, motility and viability in rats treated with Co-artesiane were reduced when compared with controls. Biochemical analyses showed increase in the activities of oxidative stress markers in a dose-dependent manner. The results suggest that the graded dose of Co-artesiane® elicit depletion of antioxidant defense system and induced oxidative stress in the rats
Parameter Estimation of Transient Multiexponential Signals Using SVD-ARMA and Multiparameter Deconvolution Techniques
Get PDFMuch has been reported about the analysis of transient multiexponentials data. In a previous paper, for example, this analysis was done using autoregressive moving average model which was applied to the deconvolved data arising from the application of Gardner transform followed by optimal compensation deconvolution to the original signal. Optimal compensation deconvolution uses a single parameter noise-reduction parameter. In this paper, a deconvolution parameter incorporating multiple noise-reduction parameters is used instead. Simulations and experimental results show that the proposed combination, despite its limitations supersedes several existing methods
/8/4
Get PDFHuman hand posture detection and recognition is a challenging problem in computer vision. We introduce an algorithm that is capable to recognize hand posture in a sophisticated background. The system combines two algorithms to achieve better detection rate for hand. Recently Viola et al. in have introduced a rapid object detection scheme; we use this approach to detect the hand posture in the first set of consecutive frames. The chromatic color distribution of skin can be found within this cluster. As the shape of hand posture keep changing in the subsequent frames, the skin regions updated dynamically. The classification of hand posture makes use of static feature for locating and counting hand fingers. Kalman Filter is used to track the face and hand blobs based on their position. In the experiments, we have tested our system in various environments, and results showed effectiveness of the approach
Biodegradation of p-Chloroaniline by Bacteria Isolated from Contaminated Sites
Get PDFEnrichment of water from a contaminated site in a textile industry in Ikeja resulted in the isolation of two
bacteria belonging to the genera Alcaligenes and Cellulomonas. These bacteria were able to mineralize
para-chloroaniline (p-chloroaniline). Time course degradation of p-chloroaniline using pure cultures of
these organisms showed that p-chloroaniline supported the growth of these isolates. An initial increase
in cell densities of 7.50-9.46 cfu/mL was recorded from day 0-9th day for Cellulomonas sp. while for
Alcaligenes denitrificans it was 7.20-9.40 cfu/mL. After day 9, a decrease in population occurred,
indicating non-availability of nutrients or toxicity of the medium. Simultaneously, a decrease in the pH,
indicative of increased acidity of the medium, was also observed from the first day. The result of the GC
analysis of the pure isolates on p-chloroaniline shows that 86.5% of the p-chloroaniline was degraded
by the Cellulomonas sp. while 81.2% was degraded by the A. denitrificans in 30 days. These bacterial
isolates utilized other hydrocarbons such as pyrene, anthracene, crude oil and chlorobenzoates as sole
source of carbon and energy but not phenanthrene, naphthalene and biphenyl. The two isolates
tolerated NaCl concentration of up to 5%
Effect of sampling on the parameter estimates of multicomponent transients
Get PDFThe need to estimate the parameters of transient multiexponential signals frequently
arises in different areas of applied science. A classical technique that has been
frequently used with different modifications is the Gardner transform. Gardner transform
is used to convert the original data signal into a convolution model. Converting this
model into a discrete type for further analysis depends on the selection of correct
sampling conditions. Previously, a relationship between the sampling frequency and the
weighting factor in the modified Gardner transform was derived. In this paper, the effect
of this relationship on the accuracy of parameter estimates is investigated
Involvement of non-professionals in cataloguing: a survey of practices in three academic libraries in Nigeria
Get PDFThe study examined the involvement of non-professionals in cataloguing practices in three academic libraries in Nigeria. Twenty five respondents comprising current cataloguers and those who had worked as cataloguers were used for the study. A descriptive survey method using a self-constructed questionnaire was used. Four research questions were posed and analysed using frequency counts and percentages. Results showed that the involvement of non-professionals in cataloguing is fast
becoming a reality, with one university library depending more on non-professionals while the other two showed less dependence on them. Methods adopted by these libraries to ensure quality control include close supervision by professionals, training non-professionals in copy cataloguing, and designation of a librarian to constantly edit the catalogue for possible re-cataloguing. The use of prepared worksheets by librarians to be keyed in by non-professionals is the least used strategy. Other major findings include changes in cataloguing practices which comprise online cataloguing,
cataloguing of Internet resources and electronic files, copy-cataloguing, different metadata structures, introduction of OPAC and the involvement of non-professionals in cataloguing practices. Outsourcing, procurement of ICT, employment of Systems Engineers as part of library staff, attendance of workshops and conferences among others were some of the strategies adopted to cope with these changes; however, the application of ICT was the most frequently used strategy. The study concluded that cataloguing practices in the libraries sampled have witnessed changes as a result of the application of ICT in organizing library materials which has in turn changed the role of
cataloguers from merely providing bibliographic details of materials to that of supervision and other administrative functions, and in order to maintain relevance, librarians have been forced to build capacity in the area of ICT
Effect of Corn Steep liquor on growth rate and Pyrene Degradation by Pseudomonas strain
No full textThe growth rates and pyrene degradation rates of Pseudomonas sp. LPl and Pseudomonas aeruginosa LP5 were increased in corn steep liquor (CSL) supplemented. On pyrene alone the higher specific growth rate of LPl was 0.818 h-1, while on CSL-supplemented pyrene MSM, the value was 0.026 h-1. For LP5 the highest growth rate on CSL-supplemented pyrene-MSM was 0.034 h-1. Conversely, on pyrene alone the highest rate was 0.024 h-1. CSL led to marked reduction in residual pyrene. In the case of Pseudomonas sp. LPl values of residual pyrene were 58.54 and 45.47 %, respectively, for the unsupplemented and supplanted both cultures, showing a difference of 13.09 %. For LP5 the corresponding values were 64.01 and 26.96 %, respectively, showing a difference of 37.05 %. The rate of pyrene utilization by LPl were 0.08 and 0.11 mg l-1 h-1 on unsupplemented and supplemented media, respectively. The corresponding values for LP5 were 0.07 and 0.015 mg l-1 h-1, respectively. These results suggest that CSL, a cheap and readily available waste product, could be very useful in the bioremediation of environments contaminated with pyrene
Evaluation of in-vitro antioxidant activities of methanol extracts of Persea americana and Cnidosculus aconitifolius
No full textThe present study was undertaken to investigate the antioxidant activities of Persea americana and Cnidosculous aconitifolius. The in-vitro antioxidant activity of the methanol extracts of the leaves of Persea americana and Cnidosculous aconitifolius was evaluated using various experimental methods such as 1,1-diphenyl-2-picryl-hydrazyl (DPPH), nitric oxide and reducing power radical-scavenging activity assay. Phytochemical screening as well as the amounts of total phenol and flavonoids were also determined. The present study revealed that both the methanol extracts of the leaves of Persea americana and Cnidosculous aconitifolius possess significant antioxidant activities. However, Persea americana was found to have higher radical scavenging activity than Cnidosculous aconitifolius but the phenol content of Cnidosculous aconitifolius was higher than that of Persea americana whereas Persea americana was observed to possess more flavonoids than Cnidosculous aconitifolius