48 research outputs found

    Elemental Spatiotemporal Variations of Total Suspended Particles in Jeddah City

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    Elements associated with total suspended particulate matter (TSP) in Jeddah city were determined. Using high-volume samplers, TSP samples were simultaneously collected over a one-year period from seven sampling sites. Samples were analyzed for Al, Ba, Ca, Cu, Mg, Fe, Mn, Zn, Ti, V, Cr, Co, Ni, As, and Sr. Results revealed great dependence of element contents on spatial and temporal variations. Two sites characterized by busy roads, workshops, heavy population, and heavy trucking have high levels of all measured elements. Concentrations of most elements at the two sites exhibit strong spatial gradients and concentrations of elements at these sites are higher than other locations. The highest concentrations of elements were observed during June–August because of dust storms, significant increase in energy consumption, and active surface winds. Enrichment factors of elements at the high-level sites have values in the range >10~60 while for Cu and Zn the enrichment factors are much higher (~0–>700) indicating that greater percentage of TSP composition for these three elements in air comes from anthropogenic activities

    Towards Idiomatic Competence of Yemeni EFL Undergraduates

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    This study investigates how Yemeni EFL undergraduates recognize, comprehend, and use English idioms. It attempts to find out the link between English proficiency and idiomatic competence of a sample of 63 sophomores recruited from the Department of English at the Faculty of Education, Taiz University. Three idiom tests and a questionnaire were used to answer three research questions: a) To what extent are Yemeni EFL undergraduates able to process English idioms? b) What strategies do they use to learn idioms? c) What challenges do they encounter in acquiring idiomatic expressions? Findings of the study show that high-scoring students in the idiom tests outperformed their low-scoring counterparts in achievement tests of listening and speaking skills. The study highlighted some major challenges that face Yemeni EFL learners and the strategies they tend to use in order to tackle those challenges. Some implications and recommendations were suggested accordingly

    Liquid chromatographic-mass spectrometric method for determination of drug content uniformity of two commonly used dermatology medications in a split-tablet dosage form

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    Purpose: To develop and validate a simple, efficient and reliable Liquid  chromatographic-mass spectrometric (LC-MS/MS) method for the quantitative determination of two dermatological drugs, Lamisil® (terbinafine) and Proscar® (finasteride), in split tablet dosage form.Methods: Thirty tablets each of the 2 studied medications were randomly selected. Tablets were weighed and divided into 3 groups. Ten tablets of each drug were kept intact, another group of 10 tablets were manually split into halves using a tablet cutter and weighed with an analytical balance; a third group were split into quarters and weighed. All intact and split tablets were individually dissolved in a water: methanol mixture (4:1), sonicated, filtered and further diluted with mobile phase. Optimal chromatographic separation and mass spectrometric detection were achieved using an Agilent 1200 HPLC system coupled with an Agilent 6410 triple quadrupole mass spectrometer. Analytes were eluted through an Agilent eclipse plus C8 analytical column (150 mm × 4.6 mm, 5 μm) with a mobile phase composed of solvent A (water) containing 0.1% formic acid and 5mM ammonium formate pH 7.5, and solvent B (acetonitrile mixed with water in a ratio A:B 55:45) at a flow rate of 0.8 mL min-1 with a total run time of 12 min. Mass spectrometric detection was carried out using positive ionization mode with analyte quantitation monitored by multiple reaction monitoring (MRM) mode.Results: The proposed analytical method proved to be specific, robust and  adequately sensitive. The results showed a good linear fit over the concentration range of 20 - 100 ng mL-1 for both analytes, with a correlation coefficient (r2) ≥ 0.999 and 0.998 for finasteride and terbinafine, respectively. Following tablet splitting, the drug content of the split tablets fell outside of the proxy USP  specification for at least 14 halves (70 %) and 34 quarters (85 %) of FIN, as well as 16 halves (80 %) and 37 quarters (92.5 %) of TBN. Mean weight loss, after splitting, was 0.58 and 2.22 % for FIN half- and quarter tablets, respectively, and 3.96 and 4.09 % for TBN half- and quarter tablets,respectively.Conclusion: The proposed LC-MS/MS method has successfully been used to provide precise drug content uniformity of split tablets of FIN and TBN. Unequal distribution of the drug on the split tablets is indicated by the high standard deviation beyond the accepted value. Hence, it is recommended not to split non-scored tablets  especially, for those medications with significant toxicityKeywords: Tablet splitting, Finasteride, Terbinafine, Drug content uniformity,  LC-MS/M

    TECTONIC AND EROSION FEATURES, AND THEIR INFLUENCE ON ZONAL DISTRIBUTION OF THE UPPER TRIASSIC AND THE LOWER CRETACEOUS SEDIMENTS IN THE EUPHRATES GRABEN AREA, SYRIA

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    We have investigated the tectonic and erosion features of the Upper Triassic (Mulussa F Formation) and Lower Cretaceous (Rutbah Formation) sediments in the Euphrates graben area and analysed their influence on changes in the thickness and zonal distribution patterns of these sediments. In this study, the geological modeling software of Petrel Schlumberger is used to model the regional geological structure and stratigraphy from the available geological and geophysical data.The Upper Triassic and Lower Cretaceous sediments (in total, almost 800 m thick) are the major hydrocarbon reservoirs in the Euphrates graben, which contain approximately 80 to 90 % of the total hydrocarbon reserve in this area. These sedimentary zones experienced variable changes in thickness and zonal distribution due to erosion processes caused by the two major regional unconformities, the Base Upper Cretaceous (BKU) and Base Lower Cretaceous (BKL) unconformities. The maximum thickness of the Upper Triassic sediments amounts to 480 m in the central parts of the Euphrates graben and along the NW-SE trend, i.e. in the dip direction of the Upper Triassic Mulussa F Formation. Towards the NE flank of the graben near the Khleissia uplift and the SW flank near to the Rutbah uplift, the thickness of the Upper Triassic sediments is gradually decreased due to their partial or total erosion caused by the BKL unconformity, and also due to a less space for sediment accumulation near the uplifts. The thickness of the Lower Cretaceous sediments increases in the northern, NW and NE flanks of the graben. Their maximum thickness is about 320 m. The BKL unconformity is the major cause of erosion of the Lower Cretaceous sediments along the southern, SE and SW flanks of the graben. In the Jora and Palmyra areas towards the NW flank of the Euphrates graben, the Upper Triassic and Lower Cretaceous sediments show no changes in thickness. In these areas, there was more space for sediment accumulation, and the sediments were less influenced by the BKL and BKU unconformities and thus less eroded

    ТЕКТОНИЧЕСКИЕ И ЭРОЗИОННЫЕ ОСОБЕННОСТИ И ИХ ВЛИЯНИЕ НА ЗОНАЛЬНОЕ РАСПРЕДЕЛЕНИЕ ВЕРХНЕТРИАСОВЫХ И НИЖНЕМЕЛОВЫХ ОТЛОЖЕНИЙ ЕВФРАТСКОГО ГРАБЕНА (СИРИЯ)

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    We have investigated the tectonic and erosion features of the Upper Triassic (Mulussa F Formation) and Lower Cretaceous (Rutbah Formation) sediments in the Euphrates graben area and analysed their influence on changes in the thickness and zonal distribution patterns of these sediments. In this study, the geological modeling software of Petrel Schlumberger is used to model the regional geological structure and stratigraphy from the available geological and geophysical data.The Upper Triassic and Lower Cretaceous sediments (in total, almost 800 m thick) are the major hydrocarbon reservoirs in the Euphrates graben, which contain approximately 80 to 90 % of the total hydrocarbon reserve in this area. These sedimentary zones experienced variable changes in thickness and zonal distribution due to erosion processes caused by the two major regional unconformities, the Base Upper Cretaceous (BKU) and Base Lower Cretaceous (BKL) unconformities. The maximum thickness of the Upper Triassic sediments amounts to 480 m in the central parts of the Euphrates graben and along the NW-SE trend, i.e. in the dip direction of the Upper Triassic Mulussa F Formation. Towards the NE flank of the graben near the Khleissia uplift and the SW flank near to the Rutbah uplift, the thickness of the Upper Triassic sediments is gradually decreased due to their partial or total erosion caused by the BKL unconformity, and also due to a less space for sediment accumulation near the uplifts. The thickness of the Lower Cretaceous sediments increases in the northern, NW and NE flanks of the graben. Their maximum thickness is about 320 m. The BKL unconformity is the major cause of erosion of the Lower Cretaceous sediments along the southern, SE and SW flanks of the graben. In the Jora and Palmyra areas towards the NW flank of the Euphrates graben, the Upper Triassic and Lower Cretaceous sediments show no changes in thickness. In these areas, there was more space for sediment accumulation, and the sediments were less influenced by the BKL and BKU unconformities and thus less eroded.На основе региональной структурной и стратиграфической геологический модели с использованием выбранных геолого-геофизическх данных и с помощью геологического программного обеспечения «Petrel Schlumberger» были изучены и обобщены тектонические и эрозионные особенности и их влияние на зональное распространение и изменение мощности осадочных отложений верхнетриасовых (формация Мулусса Ф) и нижнемеловых (формация Рутба) отложений вдоль Евфратского грабена.Верхнетриасовые и нижнемеловые отложения (суммарная мощность около 800 м), считающиеся основными пластами-коллекторами углеводородов вдоль месторождений Евфратского грабена, содержат приблизительно от 80 до 90 % объема углеводородов, сохранившихся в этом районе. Осадочные зоны верхнетриасовых и нижнемеловых отложений Евфратского грабена подвергались различным изменениям в зональном распространении и мощности из-за эрозии, вызванной комплексом региональных несогласий вдоль Евфратского грабена. Этими несогласиями являются базовое верхнемеловое несогласие (BKU) и базовое нижнемеловое несогласие (BKL). Максимальная мощность 480 м верхнетриасовых отложений сохранилась в центральной части Евфратского грабена и в направлении с северо-запада на юго-восток, это направление погружения верхнетриасовой формации Мулусса Ф. Мощность верхнетриасовых отложений постепенно уменьшалась к северо-восточным флангам грабена вблизи поднятия Хлейсса и к юго-западным флангам вблизи поднятия Рутба из-за частичного или полного среза этих отложений в результате эрозии, вызванной несогласием BKL, и из-за меньшего пространства для накопления осадков вблизи этих поднятий. Максимальная мощность нижнемеловых отложений приблизительно 320 м, при этом толщина осадков увеличивается на северном, северо-западном и северо-восточном флангах Евфратского грабена. Наибольшая степень эрозии вследствие влияния несогласия BKU на нижнемеловые отложения отмечается вдоль южного, юго-восточного и юго-западного флангов Евфратского грабена. Толщина верхнетриасовых и нижнемеловых отложений вдоль районов Жора и Пальмира к северо-западным флангам грабена сохраняется неизменной из-за меньшего влияния эрозии, вызванной несогласиями BKL и BKU, а также из-за большего пространства для накопления осадков вдоль этих районов

    Using formal methods in distributed system design

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    Distributed systems are groups of networked computers, which have the same goal for their work. The terms "concurrent computing", "parallel computing", and "distributed computing" have a lot of overlap, and no clear distinction exists between them. The same system may be characterized both as "parallel" and "distributed"; the processors in a typical distributed system run concurrently in parallel. Parallel computing may be seen as a particular tightly coupled form of distributed computing, and distributed computing may be seen as a loosely coupled form of parallel computing. Nevertheless, it is possible to roughly classify concurrent systems as "parallel" or "distributed" using the following criteria. Philosophy is centrally concerned with arguments. The first question to be asked of any argument (or inference) is whether or not it is valid: That is, does its conclusion really follow from the cited premises? Validity of inference is the central problem of deductive logic. © The Authors, published by EDP Sciences, 2017

    Musculoskeletal Response to Whole-Body Vibration During Fracture Healing in Intact and Ovariectomized Rats

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    This study investigated the effect of vibration on bone healing and muscle in intact and ovariectomized rats. Thirty ovariectomized (at 3 months of age) and 30 intact 5-month old female Sprague-Dawley rats underwent bilateral metaphyseal osteotomy of tibia. Five days later, half of the ovariectomized and of the intact rats were exposed to whole-body vertical vibration (90 Hz, 0.5 mm, 4 × g acceleration) for 15 min twice a day during 30 days. The other animals did not undergo vibration. After decapitation of rats, one tibia was used for computed tomographic, biomechanical, and histological analyses; the other was used for gene expression analyses of alkaline phosphatase (Alp), osteocalcin (Oc), tartrate-resistant acid phosphatase 1, and insulinlike growth factor 1. Serum Alp and Oc were measured. Mitochondrial activity, fiber area and distribution, and capillary densities were analyzed in M. gastrocnemius and M. longissimus. We found that vibration had no effect on body weight and food intake, but it improved cortical and callus densities (97 vs. 99%, 72 vs. 81%), trabecular structure (9 vs. 14 trabecular nodes), blood supply (1.7 vs. 2.1 capillaries/fiber), and oxidative metabolism (17 vs. 23 pmol O2/s/mg) in ovariectomized rats. Vibration generally increased muscle fiber size. Tibia biomechanical properties were diminished after vibration. Oc gene expression was higher in vibrated rats. Serum Alp was increased in ovariectomized rats. In ovariectomized rats, vibration resulted in an earlier bridging; in intact rats, callus bridging occurred later after vibration. The chosen vibration regimen (90 Hz, 0.5 mm, 4 × g acceleration, 15 min twice a day) was effective in improving musculoskeletal tissues in ovariectomized rats but was not optimal for fracture healing

    Enhanced Photocatalytic Activity of ZrO2-SiO2 Nanoparticles by Platinum Doping

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    ZrO2-SiO2 mixed oxides were prepared via the sol-gel method. Photo-assisted deposition was utilized for doping the prepared mixed oxide with 0.1, 0.2, 0.3, and 0.4 wt% of Pt. XRD spectra showed that doping did not result in the incorporation of Pt within the crystal structure of the material. UV-reflectance spectrometry showed that the band gap of ZrO2-SiO2 decreased from 3.04 eV to 2.48 eV with 0.4 wt% Pt doping. The results show a specific surface area increase of 20%. Enhanced photocatalysis of Pt/ZrO2-SiO2 was successfully tested on photo degradation of cyanide under illumination of visible light. 100% conversion was achieved within 20 min with 0.3 wt% of Pt doped ZrO2-SiO2

    Spectroscopic Assessment of Platinum Group Elements of PM10 Particles Sampled in Three Different Areas in Jeddah, Saudi Arabia

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    Platinum group elements (PGE) including Ru, Rh, Pt and Pd have been quantified in air particulate matter with an aerodynamic diameter equal or less than 10 microns (PM10) using inductively coupled plasma mass spectrometry (ICP-MS). PM10 aerosols have been collected from three sites representing various activities in Jeddah city, Saudi Arabia. These locations are residential site with heavy traffic, industrial site and heavy traffic and a light traffic site outside the city. To obtain reasonable data of the PGE concentrations, a group from 10 to 15 PM10 samples were collected every month. The annual and seasonal variation of the mass concentration of the PGE were demonstrated. In all locations, Pt and Pd were relatively higher than Ru and Rh possibly because their main use is in automobile catalytic converters. Concentrations of observed PGE in PM10 could be arranged in ascending order as: Rh < Ru < Pd < Pt. In case of Ru and Pt, there are clear similarities in terms of the overall mean concentrations at the sampling locations. Due to the high concentration of Ru, Rh and Pd at low traffic site, there are certainly other sources of these elements rather than vehicle catalytic converters. However, at the industrial/heavy traffic location, high concentrations of Ru were detected during February 2015. In addition, high Pt concentrations were also detected at the light traffic site during May 2015. Results indicate that Pt source in PM10 is mainly the automobile catalytic converters

    Using formal methods in distributed system design

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    Distributed systems are groups of networked computers, which have the same goal for their work. The terms “concurrent computing”, “parallel computing”, and “distributed computing” have a lot of overlap, and no clear distinction exists between them. The same system may be characterized both as “parallel” and “distributed”; the processors in a typical distributed system run concurrently in parallel. Parallel computing may be seen as a particular tightly coupled form of distributed computing, and distributed computing may be seen as a loosely coupled form of parallel computing. Nevertheless, it is possible to roughly classify concurrent systems as “parallel” or “distributed” using the following criteria. Philosophy is centrally concerned with arguments. The first question to be asked of any argument (or inference) is whether or not it is valid: that is, does its conclusion really follow from the cited premises? Validity of inference is the central problem of deductive logic
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