OALib Journal期刊

ISSN: 2333-9721




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匹配条件: “S.S. AL-Ahmadi” ,找到相关结果约341126条。
Further properties on strongly generalized star semi- continuous mappings
A.I. EL-Maghrabi,S.S. AL-Ahmadi
Journal of Global Research in Mathematical Archives , 2013,
Abstract: The aim of this paper is to introduce and study the class of strongly generalized star semi – closed sets which is weaker than semi- closed sets (Crossly and Hildebrand , 1971) and stronger than both strongly generalized semi-closed sets (El-Maghrabi and Nasef ,2008) and semi generalized-closed sets (Bhattacharya and Lahiri,1987). Also, through this paper some concepts such as: strongly generalized star semi –continuous, strongly generalized star semi –closed and strongly generalized star semi –homeomorphism maps are discussed and investigated via a strongly generalized star semi –closed set. (1991) AMS Math. Subject Classification: 54 A05; 54 D10 Keywords and Phrases: strongly generalized star semi –closed sets, strongly generalized star semi – continuous, strongly generalized star semi –irresolute, strongly generalized star semi- closed and strongly generalized star semi – homeomorphism mappings
Two solutions for the BVP of a rotating variable-thickness solid disk  [PDF]
Ashraf M. Zenkour, Suzan A. Al-Ahmadi
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.32021
Abstract: This paper presents the analytical and numerical solutions for a rotating variable-thickness solid disk. The outer edge of the solid disk is considered to have free boundary conditions. The governing equation is derived from the basic equations of the rotating solid disk and it is solved analytically or numerically using finite difference algorithm. Both analytical and numerical results for the distributions of stress function and stresses of variable-thickness solid disks are obtained. Finally, the distributions of stress function and stresses are presented and the appropriate comparisons and discussions are made at the same angular velocity.
Privacy-Preserving Data Mining for Horizontally-Distributed Datasets using EGADP
Mohammad Saad Al-Ahmadi
Communications of the IBIMA , 2008,
Abstract: In this paper, we investigate the possibility of using EGADP for protecting data in horizontally-distributed datasets. EGADP is a new advanced data perturbation method that masks confidential numeric attributes in original datasets while reproducing all linear relationships in masked datasets. It is developed for centralized datasets that are owned by one owner, and no study, to the best of our knowledge, suggests and investigates empirically the possibilities of using it to protect distributed confidential datasets. This study is intended to fill this gap.
A Web-Based Cancer Atlas of Saudi Arabia  [PDF]
Khalid Al-Ahmadi, Ali Al-Zahrani, Atiq Al-Dossari
Journal of Geographic Information System (JGIS) , 2013, DOI: 10.4236/jgis.2013.55044
Abstract: There is a distinct lack of online atlases to visualize and explore cancer incidence in Middle Eastern countries despite the clear benefit that such tools can deliver. This paper describes the development and implementation of a cancer Atlas of Saudi Arabia, which is a web-based client-server application with built-in analysis functions for analyzing patterns of cancer incidence. Built using ESRI’s ArcGIS Server API and ASP.NET, the atlas contains 45,532 incidences of cancer for the period from 1998 to 2004, which were provided by the Saudi Arabian National Cancer Registry. This tool is aimed at health care practitioners and researchers, who can use this tool for exploring cancer distribution and investigating trends, and as a decision support tool for service allocation. The tool allows users to map cancer incidence and undertake analyses at four spatial scales from city to national level.


Salinity Effects on Germination Properties of Kochia scoparia
M. Jami Al-Ahmadi,M. Kafi
Asian Journal of Plant Sciences , 2006,
Abstract: In order to examine seed germination responses of kochia to different levels of salinity, an experiment was performed in the Institute of Sustainable Agriculture (CSIC), Cordoba, Spain, in a Completely Randomized Design with two replications. Treatments were different levels of salinities equal to 0, 5, 10, 15 and 20 dS m-1, obtained by mixing NaCl and CaCl2 in a 2:1 molar ratio. Evaluated properties were germination percentage, rate and final number of germinated seeds. The results showed that the germinated seed number and the germination percentage had an inverse relation with salinity of substrate. About 91% of seeds germinated in distilled water. This value reduced to about 36% in 20 dS m-1. Increasing salinity up to 10 dS m-1 did not have any significant effect on germination, but after that, the germination rate and percentage began to reduce significantly. Salinity also increased the time required for 50%germination from 28 h in distilled water to 78 h in 20 dS m-1, showing a delay in germination as salinity increased. Regarding linear reduction in germination rate in response to increase in salinity, it seems that as salinity exceeds 30 dS m-1, germination rate of kochia approaches to zero. This perhaps can be accepted as the threshold of kochia germination tolerance to salinity. According to the results, the germination stage of kochia has a good tolerance to elevated levels of salinities and it seems that a good stand establishment in saline soils and water conditions can be insured, if proper management is exerted in farms.
NO2 and Cancer Incidence in Saudi Arabia
Khalid Al-Ahmadi,Ali Al-Zahrani
International Journal of Environmental Research and Public Health , 2013, DOI: 10.3390/ijerph10115844
Abstract: Air pollution exposure has been shown to be associated with an increased risk of specific cancers. This study investigated whether the number and incidence of the most common cancers in Saudi Arabia were associated with urban air pollution exposure, specifically NO 2. Overall, high model goodness of fit (GOF) was observed in the Eastern, Riyadh and Makkah regions. The significant coefficients of determination (r 2) were higher at the regional level (r 2 = 0.32–0.71), weaker at the governorate level (r 2 = 0.03–0.43), and declined slightly at the city level (r 2 = 0.17–0.33), suggesting that an increased aggregated spatial level increased the explained variability and the model GOF. However, the low GOF at the lowest spatial level suggests that additional variation remains unexplained. At different spatial levels, associations between NO 2 concentration and the most common cancers were marginally improved in geographically weighted regression (GWR) analysis, which explained both global and local heterogeneity and variations in cancer incidence. High coefficients of determination were observed between NO 2 concentration and lung and breast cancer incidences, followed by prostate, bladder, cervical and ovarian cancers, confirming results from other studies. These results could be improved using individual explanatory variables such as environmental, demographic, behavioral, socio-economic, and genetic risk factors.
Spatial Autocorrelation of Cancer Incidence in Saudi Arabia
Khalid Al-Ahmadi,Ali Al-Zahrani
International Journal of Environmental Research and Public Health , 2013, DOI: 10.3390/ijerph10127207
Abstract: Little is known about the geographic distribution of common cancers in Saudi Arabia. We explored the spatial incidence patterns of common cancers in Saudi Arabia using spatial autocorrelation analyses, employing the global Moran’s I and Anselin’s local Moran’s I statistics to detect nonrandom incidence patterns. Global ordinary least squares (OLS) regression and local geographically-weighted regression (GWR) were applied to examine the spatial correlation of cancer incidences at the city level. Population-based records of cancers diagnosed between 1998 and 2004 were used. Male lung cancer and female breast cancer exhibited positive statistically significant global Moran’s I index values, indicating a tendency toward clustering. The Anselin’s local Moran’s I analyses revealed small significant clusters of lung cancer, prostate cancer and Hodgkin’s disease among males in the Eastern region and significant clusters of thyroid cancers in females in the Eastern and Riyadh regions. Additionally, both regression methods found significant associations among various cancers. For example, OLS and GWR revealed significant spatial associations among NHL, leukemia and Hodgkin’s disease (r2 = 0.49–0.67 using OLS and r2 = 0.52–0.68 using GWR) and between breast and prostate cancer (r2 = 0.53 OLS and 0.57 GWR) in Saudi Arabian cities. These findings may help to generate etiologic hypotheses of cancer causation and identify spatial anomalies in cancer incidence in Saudi Arabia. Our findings should stimulate further research on the possible causes underlying these clusters and associations.
Coherent State Monitoring in Quantum Dots
Ameenah N. Al-Ahmadi,Sergio E. Ulloa
Physics , 2004, DOI: 10.1103/PhysRevB.70.201302
Abstract: We study the dynamics of excitonic states in dimer and trimer arrangements of colloidal quantum dots using a density matrix approach. The dots are coupled via a dipole-dipole interaction akin to the F\"orster mechanism. Coherent oscillations of tuned donor dots are shown to appear as plateaus in the acceptor dot, and therefore in its optical response. This behavior provides one with an interesting and unique handle to monitor the quantum state of the dimer, an "eavesdroping arrangement." A trimer cluster in a symmetrical loop shows steady states in a shorter characteristic time than the typical radiative lifetime of the dots. Breaking the symmetry of the loop results again in damping oscillatory states in the donor dots and plateaus in the eavesdropping/acceptor dot. The use of realistic parameters allows direct comparison with recent experiments and indicates that coherent state monitoring is possible in real experiments.
Promotive Effect of 5-amino Levulinic Acid on Growth and Yield of Wheat Grown under Dry Conditions
S.S. Al-Thabet
Journal of Agronomy , 2006,
Abstract: Impact of water stress on growth and yield of wheat (Triticum aestivum vulgare L.) with and without foliar spraying 5-amino Levulinic Acid (5-ALA) was studied. Role of 5-ALA on water use efficiency under water stress was also evaluated. Results showed that irrigation wheat weekly was associated with the highest biological and grain yields ha-1. Water stress by prolonging irrigation interval to 21 days resulted in a significant reduction in all estimated characters, except harvest index. However, maximum Water Use Efficiency of Biological Yield (WUEB) produced with the irrigation every 14 days. 5-ALA enhanced growth and increased yield of wheat, compared with the control. Foliar spraying of 100 ppm 5-ALA ha-1 produced the highest biological and grain yields ha-1 as well as water use efficiency. Application of 100 ppm 5-ALA enhanced the tolerance of wheat to water stress. The interaction between irrigation treatments and 5-ALA concentrations significantly affected biological and grain yields ha-1 as well as WUEB and WUEG (Water Use Efficiency of Grain yield). Wheat plants that irrigated every 14 days and foliar sprayed with 50-100 ppm 5-ALA ha-1 out yielded and surpassed in WUE that grown under normal water status (irrigation every 7) and left without 5-ALA application. So, it can be concluded that foliar application of 5-AlA on wheat plants grown under drought condition as in Saudi Arabia can enhance the tolerance to drought and increase grain yield.
Sustained virological response in a predominantly hepatitis C virus genotype 4 infected population
Yaser Dahlan, Hafiz-Mughees Ather, Majid Al-ahmadi, Faisal Batwa, Waleed Al-hamoudi
World Journal of Gastroenterology , 2009,
Abstract: AIM: To assess sustained virological response (SVR) rates in a predominantly hepatitis C virus (HCV) genotype 4 infected population.METHODS: Between 2003-2007, 240 patients who were treated for chronic hepatitis C infection at our center were included. Epidemiological data, viral genotypes, and treatment outcomes were evaluated in all treated patients. Patients with chronic renal failure, previous non-responders, and those who relapsed after previous treatment were excluded from the study. Among all patients, 57% were treated with PEG-interferon (IFN) α-2a and 43% patients were treated with PEG-IFN α-2b; both groups received a standard dose of ribavirin.RESULTS: 89.6% of patients completed the treatment with an overall SVR rate of 58%. The SVR rate was 54% in genotype 1, 44% in genotype 2, 73% in genotype 3, and 59% in genotype 4 patients. There was no statistical difference in the SVR rate between patients treated with PEG-IFN α-2a and PEG-IFN α-2b (61.5% vs 53%). Patients younger than 40 years had higher SVR rates than older patients (75% vs 51%, P = 0.001). SVR was also statistically significantly higher when the HCV RNA load (pretreatment) was below 800.000 (64% vs 50%, P = 0.023), in patients with a body mass index (BMI) less than 28 (65% vs 49%, P = 0.01), and in patients who completed the treatment duration (64% vs 8%, P ≤ 0.00001).CONCLUSION: The SVR rate in our study is higher than in previous studies. Compliance with the standard duration of treatment, higher ribavirin dose, younger age, lower BMI, and low pretreatment RNA levels were associated with a higher virological response.

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