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OALib Journal期刊

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Modeling Wind Energy Using Copula  [PDF]
Zuhair Bahraoui, Fatima Bahraoui, M. Amin Bahraoui
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104984
Abstract:
In most studies related to wind energy, the quantity of the air density is consid-ered constant, but actually, we know that it is variable and depending on others natural factors. We present a new procedure to estimate the wind density power energy by simulating the components of the air density. The procedure uses the copula theory and demonstrates that the estimated power energy is higher if the air density is not constant.
HIV-1 Tat Protein Induces the Production of IDO in Human Monocyte Derived-Dendritic Cells through a Direct Mechanism: Effect on T Cells Proliferation
Rémi Planès, Elmostafa Bahraoui
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074551
Abstract: During HIV-1 infection, an increase of indoleamine 2,3 dioxygenase (IDO) expression, and dendritic cells (DC) dysfunction were often associated with AIDS disease progression. In this work, we investigated the effect of HIV-1 Tat protein on the expression of IDO, in MoDCs. We show that Tat induces IDO protein expression and activity in a dose dependent manner by acting at the cell membrane. Using Tat-mutants, we show that the N-Terminal domain, Tat 1–45, but not the central region, Tat 30–72, is sufficient to induce the expression of active IDO. Tat protein is also able to induce several cytokines in MoDCs, including IFN-γ, a strong inducer of IDO. In order to understand whether IDO is induced directly by Tat protein or indirectly following IFN-γ production, complementary experiments were performed and showed that: i) at the kinetic level, Tat induced IDO expression before the production of IFN-γ ii) treatment of MoDCs with Tat-conditioned medium was unable to stimulate IDO expression, iii) coculture of MoDCs in a transwell cell system did not allow IDO expression in MoDCs not previously treated by Tat, iv) direct contact between Tat-treated and untreated MoDCs was not sufficient to induce IDO expression in a Tat-independent manner, and v) treatment of MoDCs in the presence of IFN-γ pathway inhibitors, Jak I and Ly294002, inhibited IFN-γ-induced IDO but had no effect on Tat-induced IDO. At the functional level, our data showed that treatment of MoDCs with Tat led to the inhibition of their capacity to stimulate T cell proliferation. This impairement was totally abolished when the stimulation was performed in the presence of 1MT, an inhibitor of IDO activity, arguing for the implication of the kynurenine pathway. By inducing IDO, Tat protein may be considered, as a viral pathogenic factor, in the dysregulation of the DC functions during HIV-1 infection.
Biology and distribution of butterfly fauna of Hazara University, Garden Campus, Mansehra, Pakistan  [PDF]
Farzana Perveen, Fatima Fazal
Open Journal of Animal Sciences (OJAS) , 2013, DOI: 10.4236/ojas.2013.32A004
Abstract: The butterflies are beautiful creature of nature with great economic importance as pollinator as well as bio-indicator of environments. The present survey was conducted to determine the biology and distribution of butterfly fauna of Hazara University, Garden Campus, Mansehra, Pakistan during March-June 2012. The study area was divided into 3 quadrates, i.e., residential area, administration area and main campus. A total of 170 specimens were collected, 10 species were identified belonging to 3 different families and falling in 8 genera. The species were identified. The painted lady, Cynthia cardui (Linnaeus); blue pansy, Junonia orithya Linnaeus; and plain tiger, Danaus chrysippus (Linnaeus) were belonging to family Nymphalidae. The lime butterfly, Papilio demoleus Linnaeus and com-mon mormon, P. polytes Linnaeus were belonging to family Papilionidae. The dark clouded yellow, Colias croceus (Geoffroy); common grass yellow, Eumera hecab (Linnaeus); Murree green-veined white, Pieris ajaka Moore; green-veined white, P. napi (Linnaeus) and Bath white, Pontia daplidice (Linnaeus) were belonging to family Pieridae. The body sizes of E. hecabe and J. orithya were minimum, i.e.
Studies on Phytochemical Evaluation and Antibacterial Properties of Two Varieties of Kolanut (Cola nitida) in Nigeria  [PDF]
S. Muhammad, A. Fatima
Journal of Biosciences and Medicines (JBM) , 2014, DOI: 10.4236/jbm.2014.23006
Abstract: Kola nut is a native stimulant which is commonly chewed in many West African cultures, individually or in a group setting. It is often used ceremonially and to honour guest. Phytochemical analysis and antibacterial screening of red and white Cola nitida (kola nut) extracts were evaluated using qualitative and quantitative method. Thin layer chromatography (TLC) was used to
evaluate the phenolic content. Antibacterial screening was done using agar well diffusion method against odontopathogens; (Lactobacillus sp., Corynebacterium haemolyticum, Proteus vulgans, Bacillus lentus, Streptococcus anginosus and Pseudomonas aeruginosa) obtained from stock cultures. Phytochemical screening revealed the presence of alkaloids, flavonoids, saponin, tannins, glycoside, steroids, volatile oil and balsams. Higher content of alkaloids, saponin and glycoside was obtained in the aqueous extract than the methanol for both red and white kola nut. The results of TLC analysis revealed the presence of quercetin and coumarin in red kola and keamferol and coumarin in white kola respectively. The result of antibacterial activity of red C. nitida showed a zone of inhibition of 18 mm and 23 mm at 60 mg/ml for aqueous extract on Proteus vulgans and
Streptococcus anginosus. Similarly white kola inhibited the growth of S. anginosus at 90 mg/ml with a zone of 18 mm. Methanol extract of red kola inhibited the growth of P. vulgans and S. anginosus at 60 mg/ml with a zone of 16 mm and 20 mm respectively. Acetone and ethyl acetate extracts of both red and white kola nut did not show any activity against the tested organism at all concentrations. The results obtained indicate that C. nitida which posses promising chemotherapeutic and antibacterial potentials respectively that could be useful against odontopathogens. The study may serve as baseline for further studies.
Biology and distribution of butterfly fauna of Hazara University, Garden Campus, Mansehra, Pakistan  [PDF]
Farzana Perveen, Fatima Fazal
Open Journal of Animal Sciences (OJAS) , 2013, DOI: 10.4236/ojas.2013.32A004
Abstract:

The butterflies are beautiful creature of nature with great economic importance as pollinator as well as bio-indicator of environments. The present survey was conducted to determine the biology and distribution of butterfly fauna of Hazara University, Garden Campus, Mansehra, Pakistan during March-June 2012. The study area was divided into 3 quadrates, i.e., residential area, administration area and main campus. A total of 170 specimens were collected, 10 species were identified belonging to 3 different families and falling in 8 genera. The species were identified. The painted lady, Cynthia cardui (Linnaeus); blue pansy, Junonia orithya Linnaeus; and plain tiger, Danaus chrysippus (Linnaeus) were belonging to family Nymphalidae. The lime butterfly, Papilio demoleus Linnaeus and common mormon, P. polytes Linnaeus were belonging to family Papilionidae. The dark clouded yellow, Colias croceus (Geoffroy); common grass yellow, Eumera hecab (Linnaeus); Murree green-veined white, Pieris ajaka Moore; green-veined white, P. napi (Linnaeus) and Bath white, Pontia daplidice (Linnaeus) were belonging to family

An Intelligent Assessment Tool for Students’ Java Submissions in Introductory Programming Courses  [PDF]
Fatima Al Shamsi, Ashraf Elnagar
Journal of Intelligent Learning Systems and Applications (JILSA) , 2012, DOI: 10.4236/jilsa.2012.41006
Abstract: This paper presents a graph-based grading system for Java introductory programming courses, eGrader. This system grades submission both dynamically and statically to ensure a complete and through grading job. While dynamic analysis is based on JUnit framework, the static analysis is based on the graph representation of the program and its quality which is measured by software metrics. The graph representation is based on the Control Dependence Graphs (CDG) and Method Call Dependencies (MCD). eGrader outperforms existing systems in two ways: the ability of grading submission with semantic-errors, effectively, and generating reports for students, as a feedback on their performance, and instructors on the overall performance of the class. eGrader is well received by instructors not only for saving time and effort but also for its high success rate that is measured by four performance indicators which are sensitivity (97.37%), specificity (98.1%), precision (98.04%) and accuracy (97.07%).
Analysis of Stochastic Reliability Characteristics of a Repairable 2-out-of-3 System with Minimal Repair at Failure  [PDF]
Ibrahim Yusuf, Fatima Salman Koki
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.48151
Abstract:

In this paper, we study the reliability and availability characteristics of a repairable 2-out-of-3 system. Failure and repair times are assumed exponential. The explicit expressions of reliability and availability characteristics such as mean time to system failure (MTSF), steady-state availability, busy period and profit function are derived using Kolmogorov’s forward equations method. Various cases are analyzed graphically to investigate the impact of system parameters on MTSF, availability, busy period and profit function.

Assessment of Profit of a Two-Stage Deteriorating Linear Consecutive 2-out-of-3 Repairable System  [PDF]
Ibrahim Yusuf, Fatima Salman Koki
Journal of Applied Mathematics and Physics (JAMP) , 2013, DOI: 10.4236/jamp.2013.13005
Abstract:

Most of the researches on profit and cost evaluation of redundant system focus on the effect of failure and repair on revenue generated. However, as these systems continue to work, their strength gradually deteriorates. Where such deterioration occurs, minor and major maintenance is employed to remedy the deterioration. Little or no attention is paid on the effect of deterioration on the impact of deterioration and their maintenance on the revenue generated. In this paper, we study the profit generated of two-stage deteriorating linear consecutive 2-out-of-3 system. Failure, repair and deterioration time are assumed exponential. The explicit expressions of availability, busy period of a repairman and profit function are derived using Kolmogorov’s forward equations method. Various cases are analyzed graphically to investigate the effect of deterioration parameters such as slow deterioration, fast deterioration, and their maintenance such as minor and major minimal maintenance on profit generated.

Evaluation of Reliability and Availability Characteristics of a Repairable System with Active Parallel Units  [PDF]
Ibrahim Yusuf, Fatima Salman Koki
Open Journal of Applied Sciences (OJAppS) , 2013, DOI: 10.4236/ojapps.2013.35044
Abstract: In this paper, we study the reliability and availability characteristics of a repairable system consisting of two subsystems A and B in series. Subsystem A consists of two units A1 and A2 operating in active parallel while subsystem B is a single unit. Failure and repair times are assumed exponential. The explicit expressions of reliability and availability characteristics like mean time to system failure (MTSF), system availability, busy period and profit function are derived using Kolmogorov forward equations method. Various cases are analyzed graphically to investigate the impacts of system parameters on MTSF, availability, busy period and profit function.
Composite Likelihood for Bilinear GARCH Model  [PDF]
Abdelhalim Bouchemella, Fatima Zahra Benmostefa
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.515225
Abstract:

In this study, we focus on the class of BL-GARCH models, which is initially introduced by Storti & Vitale [1] in order to handle leverage effects and volatility clustering. First we illustrate some properties of BL-GARCH (1, 2) model, like the positivity, stationarity and marginal distribution; then we study the statistical inference, apply the composite likelihood on panel of BL-GARCH (1, 2) model, and study the asymptotic behavior of the estimators, like the consistency property and the asymptotic normality.

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