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Endemics and endangered species in the biodiversity hotspot of the Shada Mountains, Saudi Arabia

Journal of Arid Land 2017年第1期9卷 109-121页

作者： Jacob THOMAS mohamed a el-sheikh Abdulrehman A ALATAR Department of Botany & Microbiology College of Science King Saud University Riyadh 11451 Saudi Arabia Botany Department Faculty of Science Damanhour University Damanhour 22516 Egypt

Shada Mountains in Saudi Arabia, separated by Maleel Wadi into twin mountains（i.e., Shada Alalah and Shada Asfal）, are rich in biodiversity. We investigated the diversity of endemics and endangered species of the mountains based on the data collected from 38 stands falling in 8 elevational zones ranging from 500 to 2215 m a.s.l. Results indicated that 495 plant species falling in 314 genera and 76 families occurred in the Shada Mountains, including 19 endemic species and 43 endangered species, and accounting for 22% of the total flora in Saudi Arabia. Canonical correlation analysis indicated that physiographic features, particularly altitude play an important role in the frequency and abundance of species. Endemics were not evenly distributed in the Shada Mountains and mostly restricted in the elevation zone of 1000–1500 or ＆gt;1500 m a.s.l. When the altitude reached up to 2000 m a.s.l., the endemics decreased substantially due to the significantly low temperature. The endangered species existed three different distribution patterns：（i） most endangered species distributed in the altitudes of 1000–1800 m a.s.l.;（ii） endangered trees, lianas, and shrubs occupied the altitudes 1000–1300 m a.s.l.; and（iii） endangered subshrubs and herbs inhabited the altitudes 1500–2100 m a.s.l. The results demonstrated that the biodiversity of endangered species in the Shada Mountains is high and undisturbed by invasive species, and protective measures should be taken against human disturbances to the small-scale hotspot.

关键词： elevational gradient invasion Shada Alalah Shada Asfal Wadi Jof

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Uptake of Ag, Co and Ni by the Organs of <i>Typha domingensis</i>(Pers.) Poir. ex Steud. in Lake Burullus and Their Potential Use As Contamination Indicators

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Open Journal of Modern Hydrology 2012年第1期2卷 21-27页

作者： Ebrahem M. Eid mohamed A. el-sheikh Abdulrahman A. Alatar 不详

The concentrations of Ag, Co and Ni in the sediments and the different organs of Typha domingensis from Lake Burullus, Egypt, were investigated monthly from February to September 2010 to evaluate the aquatic environment quality of the lake and to test the suitability of these organs for bio-indicating of sediment metals. The sediment heavy metals were found to decrease in the order of Ni > Co > Ag. The sediment contents of Ag were about 45 times above the worldwide range. On the other hand, Co concentrations were below the reference ranges of United States and Chinese soils. The heavy metals bioaccumulation decreased according to the order of rhizome > root > leaf for Ag;and root > rhizome > leaf for Co and Ni. It was found also that, T. domingensis had no significant differences in heavy metals concentrations over time. The transfer factors of Ag, Co and Ni from sediment to below-ground organs were smaller than one. Co had the maximum transport from below-ground to above-ground organs, while Ag had the minimum. There was a significant linear correlation between the concentration of Ag in root of T. domingensis and that in sediment. This result suggested that T. domingensis can be regarded as bio-indicator for Ag pollution of Lake Burullus.

关键词： Bio-indicators Cattails Heavy metals Lake Burullus Macrophytes Wetlands

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Ecological distribution of harmful epiphytic Oscillatoriales in Alexandria coast,Egypt,with special reference to DNA identification

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Journal of Coastal Life Medicine 2014年第4期 274-280页

作者： Amany Abdel Hamid Ismael Eman Abdel Razak mohamed Mostafa mohamed el-sheikh Wafaa Hassan Hegazy Oceanography Department Faculty of ScienceAlexandria UniversityAlexandria 21511Egypt Botany Department Faculty of ScienceDamanhuor UniversityEgypt Botany Department Faculty of ScienceTanta UniversityTantaEgypt

Objective:To identify the potentially harmful epiphytic Oscillatoriales species and follow up their distribution along Alexandria ***:Samples were collected bimonthly from April 2009 to February 2010 at three sites along Alexandria *** morphological and molecular analyses were used for identifying the dominant ***:Five species belonging to two families were identified;Oscillatoria acutissima,Oscillatoria nigroviridis,Oscillatoria sp.,Lyngbya majuscule and Phormidium *** cell density ranged from 10^(3)to 126×10^(3)filament g^(-1)fresh weight *** morphological study of the dominant species,Oscillatoria sp.(Oscillatoria sp.W1)showed much similarity with Planktothrix agardhii with no heterocysts and akinetes,while molecular ananlysis(16S rDNA)clustered the species in the same group with Anabaena ***:The 16S rDNA genes are not suitable for identifying Oscillatoriales during the present study and another molecular method should be used instead.

关键词： Harmful algae DNA analysis epiphytes Oscillatoriales Alexandria Egypt

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Effect of Natural Infection with Onion Yellow Dwarf Virus （OYDV） on Yield of Onion and Garlic Crops in Egypt

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Journal of Life Sciences 2011年第8期5卷 634-638页

作者： Salah elnagar mohamed Abdel-Kader el-sheikh Abeer Salah E1-Deen Abd E1-Wahab Department of Economic Entomology and Pesticides Faculty of Agriculture Cairo University Cairo 12613 Egypt

Present work highlights, first time in Egypt, the impact of OYDV infection on crops production. Plants grown in the field were individually labelled as either apparently healthy or diseased and were marked for harvesting. The percentage of yield loss due to viral infection was determined, on the basis of the average yield parameters of the healthy plant. The natural infection with OYDV in onion and garlic fields resulted in a substantial reduction in pseudo-stem length, number of leaves, plant weight and weight of bulb as well as number and weight of cloves. Results clearly indicate the impact of natural infection with OYDV on the crop yield of infected onion and garlic plants in comparison with the virus-free （uninfected） ones. The largest reduction in the yield of infected plants occurred in Chinese garlic （Seds40） followed by （Baladi） garlic and onion Giza 20. This information suggests that measures have to be taken to prevent natural infection with OYDV into and within onion and garlic fields in order to avoid yield loss.

关键词： Onion yellow dwarf virus (OYDV) yield reduction onion garlic.

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Laterites-bearing REEs,Wadi Natash,Southeastern Desert,Egypt

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Journal of Rare Earths 2010年第3期28卷 471-476页

作者： mohamed el-Ahmady Ibrahim Nuclear Materials Authority P.O.Box530EL MaadiCairoEgypt

The present paper recorded the occurrence of laterites-bearing REEs in Natash *** laterite deposits occur as horizons(5-15 m in thickness) at the boundary between the Cretaceous sandstones,and Natash *** was recorded in more than twenty six occurrence distributed over an area of about 500 km2 along and around Wadi *** ranges in color from light-grey,dark-grey to *** distribution of laterite deposits is structural *** results of laterites proved the...

关键词： Natash flows laterites clay minerals REEs

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Wear properties of copper and copper composites powders consolidated by high-pressure torsion

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Friction 2020年第2期8卷 433-450页

作者： mohamed Ibrahim Abd el AAL Mechanical Engineering Department College of EngineeringPrince Sattam Bin Abdulaziz UniversityWadi Addawaser 11991Saudi Arabia Mechanical Design&Production Department Faculty of EngineeringZagazig UniversityZagazig 44519Egypt

The wear characteristics of Cu and Cu-SiC composite microsize powders consolidated by cold compaction combined with sintering or high-pressure torsion(HPT)were *** HPT processed(HPTed)samples with bimodal and trimodal microstructures and fine Cu grains and SiC particle sizes have superior hardness,reasonable ductility level,and high wear *** wear mass loss and coefficient of friction of HPTed samples were remarkably lower than that of cold-compacted and sintered samples as well as that of micro and nano Cu and Cu-SiC composites from previous *** sample fabrication method has an apparent influence on the wear *** wear mechanism was converted from adhesive,delamination,three-body mechanism,grooves(take off the SiC particles),and cracks into abrasive wear after *** can be considered a dominant wear mechanism in all *** worn surface morphology and analysis support the relationship between wear mechanism and characteristics.

关键词： Cu-SiC composite powders high-pressure torsion(HPT) fine and coarse grains wear characteristics worn surface morphology

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On the Gosper’s q-constant Ⅱ_q

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Acta Mathematica Sinica,English Series 2018年第11期34卷 1755-1764页

作者： mohamed el BACHRAOUI Department Mathematical Sciences UAE University

Gosper introduced the functions sinq z and cosq z as q-analogues for the trigonometric functions sin z and cos z respectively. He stated a variety of identities involving these two q-trigonometric functions along with certain constants denoted by Πqn （n ∈ N）. Gosper noticed that all his formulas on these constants have more than two of the Πqn. So, it is natural to raise the question of establishing identities involving only two of the Πqn. In this paper, our main goal is to give examples of such formulas in only two Πqn.

关键词： q-trigonometric functions elliptic functions theta function identities

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Ore Controls and Metallogenesis of Au-Ag Deposits at Atalla Mine,Central Eastern Desert of Egypt

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Acta Geologica Sinica(English Edition) 2020年第5期94卷 1451-1470页

作者： mohamed ABD el MONSEF Geology Department Faculty of ScienceTanta UniversityTanta 31527Egypt Institute of Geological Sciences Faculty of ScienceMasaryk UniversityBrnoCzech Republic

Gold-silver deposits in the Atalla area occur as hydrothermal quartz veins in NE–SW pre-existing fractures within the Atalla granitic *** orientation of such quartz veins has been attributed to extensional behavior related to the Atalla Shear Zone(ASZ).The Atalla area is covered by a variety of lithologies that are(from oldest to youngest):metasedimentary rocks,metavolcanic rocks,ophiolite assemblage(serpentinites/talc-carbonates),Atalla granite and Dokhan volcanic ***,Atalla granite ranges in composition from granodiorite to *** geochemistry constrains the calc-alkaine affinity of the Atalla granite that was intruded within an orogenic(syncollision)tectonic *** ore minerals are represented by gold/silver(electrum),pyrite(Py1&Py2),arsenopyrite,pyrrhotite,sphalerite,chalcopyrite,galena,covellite and *** temperature of ore formation ranges from 240 to 285℃and the estimated fluid pressure is in the range of 20–100 *** on the geological setting,ore textures and fluid characteristics;the Atalla Au-Ag deposits are considered to be orogenic in nature,formed from a continental collision(~653-590 Ma),synchronous with the emplacement of calc-alkaline magmatism during the evolutionary history of the Arabian Nubian Shield(ANS).The initial ore-forming fluid was primarily derived from a metamorphic source related to ophiolitic-serpentinite rocks under deep regional conditions of greenschist-amphibolite facies,where the Atalla granitic eruption provided the required temperature conditions for the metamorphic process to take *** such conditions,the transportation of ore metals as bisulfide complexes is *** deposition of ore minerals was triggered by fluidwallrock interaction through fracture pathways in conjunction with a temperature-pressure drop that is likely to have been related to uplift into the crustal levels.

关键词： Gold-silver arsenopyrite geothermometry fluid inclusions orogenic deposits Atalla Shear Zone(ASZ)

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Comparison between seismic analysis of twisting and regular 52-story towers considering soil-structure interaction

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 663-675页

作者： mohamed Naguib Abouelsaad Mohammed Shaaban Salah el Bagalaty mohamed E.el Madawy Structural Engineering Department Faculty of EngineeringMansura UniversityMansoura 35511Egypt Faculty of Engineering Delta University for Science and TechnologyGamasa 35712Egypt

A dynamic analysis of both twisting and regular towers is carried out to determine the results of considering soil-structure interaction(SSI)on high-rise *** addition,the difference between the seismic performance of using twisting towers over regular ones is *** twisting tower is a simulation of the Evolution Tower(Moscow).The towers’skeletons consist of RC elements and rest on a reinforced concrete piled-raft *** soil model is considered as multi-layered with the same soil properties as the zone chosen for the analysis(New Mansoura City,Egypt).The only difference between both towers is their shape in *** whole system is modelled and analyzed in a single step as one full 3D model,which is known as the direct approach in *** analyses are carried out using finite-element software(Midas GTS NX).Dynamic output responses due to three records of seismic loads are proposed and presented in some *** on the results,it is concluded that SSI has a considerable effect on the dynamic response of tall buildings mainly because of the foundation flexibility,as it leads to lengthening the vibration period,increasing the story drift and the base shear for both cases.

关键词： soil-structure interaction seismic analysis twisting towers base shear story drift finite element method Midas GTS NX

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Heterogeneous performance analysis of the new model of CFAR detectors for partially-correlated χ~2-targets

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Journal of Systems Engineering and electronics 2018年第1期29卷 1-17页

作者： el_MASHADE mohamed Bakry electrical Engineering Department Faculty of Engineering Al Azhar University

To mitigate the deleterious effects of clutter and jammer, modern radars have adopted adaptive processing techniques such as constant false alarm rate(CFAR) detectors which are widely used to prevent clutter and noise interference from saturating the radar’s display and preventing targets from being *** paper concerns with the detection analysis of the novel version of CFAR schemes(cell-averaging generalized trimmed-mean,CATM) in the presence of additional outlying targets other than the target under research. The spurious targets as well as the tested one are assumed to be fluctuating in accordance with the χ~2-model with two-degrees of freedom. In this situation, the processor performance is enclosed by the swerling models(SWI and SWII). Between these bounds, there is an important class of target fluctuation which is known as moderately fluctuating targets. The detection of this class has many practical applications. Structure of the CATM detector is described briefly. Detection performances for optimal, CAM, CA, trimmed-mean(TM) and ordered-statistic(OS) CFAR strategies have been analyzed and compared for desired probability of false alarm and determined size of the reference window. False alarm rate performance of these processors has been evaluated for different strengths of interfering signal and the effect of correlation among the target returns on the detection and false alarm performances has also been studied. Our numerical results show that, with a proper choice of trimming parameters,the novel model CAM presents an ideal detection performance outweighing that of the Neyman-Pearson detector on condition that the tested target obeys the SWII model in its fluctuation. Although the new models CAS and CAM can be treated as special cases of the CATM algorithm, their multi-target performance is modest even it has an enhancement relative to that of the classical CAcheme. Additionally, they fail to maintain the false alarm rate constant when the operati

关键词： adaptive target detection multi-pulse performance noise and interference partially-correlated χ~2-targets SWI & SWII target fluctuation models target multiplicity environments

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