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1

Groundwater sapping processes, Western Desert, Egypt.  

SciTech Connect

Depressions of the Western Desert of Egypt (specifically, Kharga, Farafra, and Kurkur regions) are mainly occupied by shales that are impermeable, but easily erodible by rainfall and runoff, whereas the surrounding plateaus are composed of limestones that are permeable and more resistant to fluvial erosion under semiarid to arid conditions. Scallop-shaped escarpment edges and stubby-looking channels that cut into the plateau units are suggestive of slumping of limestones by ground-water sapping at the limestone-shale interfaces, removal of slump blocks by weathering and fluvial erosion, and consequent scarp retreat. Spring-derived tufa deposits found near the limestone escarpments provide additional evidence for possible ground-water sapping during previous wet periods. A computer simulation model was developed to quantify the ground-water sapping processes, using a cellular automata algorithm with coupled surface runoff and ground-water flow for a permeable, resistant layer over an impermeable, friable unit. Erosion, deposition, slumping, and generation of spring-derived tufas were parametrically modeled. Simulations using geologically reasonable parameters demonstrate that relatively rapid erosion of the shales by surface runoff, ground-water sapping, and slumping of the limestones, and detailed control by hydraulic conductivity inhomogeneities associated with structures explain the depressions, escarpments, and associated landforms and deposits. Using episodic wet pulses, keyed by {delta}{sup 18}O deep-sea core record, the model produced tufa ages that are statistically consistent with the observed U/Th tufa ages. This result supports the hypothesis that northeastern African wet periods occurred during interglacial maxima. The {delta}{sup 18}O-forced model also replicates the decrease in fluvial and sapping activity over the past million years, as northeastern Africa became hyperarid. The model thus provides a promising predictive tool for studying long-term landform evolution that involves surface and subsurface processes and climatic change.

Luo, W.; Arvidson, R.E.; Sultan, M.; Becker, R.; Crombie, M.K.; Sturchio, N.; El Alfy, Z.; Environmental Research; Washington Univ.; Egyptian Geological Survey and Mining Authority

1997-01-01

2

Radiological assessment of Abu-Tartur phosphate, Western Desert Egypt.  

PubMed

The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in sedimentary phosphate rock samples (Abu-Tartur phosphate, Western Desert Egypt) by using gamma spectrometry (NaI (Tl) 3"x 3"). Phosphate and environmental samples were collected from Abu-Tartur phosphate mine and the surrounding region. The results are discussed and compared with the levels in phosphate rocks from different countries. The activities of (226)Ra, (232)Th series and (40)K are between (14.9 +/- 0.8 and 302.4 +/- 15.2), (2.6 +/- 1.0 and 154.9 +/- 7.8) and (10.0 +/- 0.5 and 368.4 +/- 18.4) Bq kg(-1), respectively. The Abu-Tartur phosphate deposit was found to have lower activity than many others exploited phosphate sedimentary deposits, with its average total annual dose being only 114.6 microSv y(-1). This value is about 11.46% of the 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection (ICRP-60, 1990) as the maximum annual dose to members of the public. PMID:18252854

Uosif, M A M; El-Taher, A

2008-01-01

3

Ground-water sapping processes, Western Desert, Egypt  

SciTech Connect

Depressions of the Western Desert of Egypt (specifically, Kharga, Farafra, and Kurkur regions) are mainly occupied by shales that are impermeable, but easily erodible by rainfall and runoff, whereas the surrounding plateaus are composed of limestones that are permeable and more resistant to fluvial erosion under semiarid to arid conditions. A computer simulation model was developed to quantify the ground-water sapping processes, using a cellular automata algorithm with coupled surface runoff and ground-water flow for a permeable, resistant layer over an impermeable, friable unit. Erosion, deposition, slumping, and generation of spring-derived tufas were parametrically modeled. Simulations using geologically reasonable parameters demonstrate that relatively rapid erosion of the shales by surface runoff, ground-water sapping, and slumping of the limestones, and detailed control by hydraulic conductivity inhomogeneities associated with structures explain the depressions, escarpments, and associated landforms and deposits. Using episodic wet pulses, keyed by {delta}{sup 18}O deep-sea core record, the model produced tufa ages that are statistically consistent with the observed U/Th tufa ages. This result supports the hypothesis that northeastern African wet periods occurred during interglacial maxima. This {delta}{sup 18}O-forced model also replicates the decrease in fluvial and sapping activity over the past million years. 65 refs., 21 figs., 2 tabs.

Luo, W.; Arvidson, R.E.; Sultan, M.; Becker, R.; Crombie, M.K. [Washington Univ., St. Louis, MO (United States)] [Washington Univ., St. Louis, MO (United States); Sturchio, N. [Argonne National Lab., IL (United States)] [Argonne National Lab., IL (United States); Alfy, Z.E. [Egyptian Geological Survey and Mining Authority, Cairo (Egypt)] [Egyptian Geological Survey and Mining Authority, Cairo (Egypt)

1997-01-01

4

Volatiles in the Desert: Subtle Remote-sensing Signatures of the Dakhleh Oasis Catastrophic Event, Western Desert, Egypt  

NASA Technical Reports Server (NTRS)

Over the past decade members of the Dakhleh Oasis Project have studied enigmatic signatures in the Pleistocene geologic record of portions of the Dakhleh oasis and palaeo-oasis in Egypt's Western Desert [1,2]. In particular, Si-Ca-Al rich glass melt (Dakhleh Glass, Fig. 1) points to a catastrophic event between c.100,000-200,000 years ago [3] in this well-studied African savannah and freshwater lake Middle Stone Age environment [4,5].

Haldemann, A. F. C.; Kleindienst, M. R.; Churcher, C. S.; Smith, J. R.; Schwarcz, H. P.; Osinski, G.

2005-01-01

5

Origin of the gypsum-rich silica nodules, Moghra Formation, Northwest Qattara depression, Western Desert, Egypt  

Microsoft Academic Search

Gypsum rich-silica nodules appear in two shale horizons of the Moghra Formation (early Miocene) northwestern Qattara Depression, Western Desert, Egypt. These nodules are gray to milky white in colour, mostly botroidal and rose-like in shape and range in diameter from 2 to 7.5 cm. The silica nodule-bearing shale is composed mainly of smectite with a little minor kaolinite.The silica nodules

Essam M. El Khoriby

2005-01-01

6

Origin of the gypsum-rich silica nodules, Moghra Formation, Northwest Qattara depression, Western Desert, Egypt  

Microsoft Academic Search

Gypsum rich-silica nodules appear in two shale horizons of the Moghra Formation (early Miocene) northwestern Qattara Depression, Western Desert, Egypt. These nodules are gray to milky white in colour, mostly botroidal and rose-like in shape and range in diameter from 2 to 7.5 cm. The silica nodule-bearing shale is composed mainly of smectite with a little minor kaolinite. The silica

Essam M. El Khoriby

2005-01-01

7

Remote sensing and geophysical investigations of Moghra Lake in the Qattara Depression, Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

The Western Desert covers two-thirds of the land area of Egypt and occupies one of the driest regions of the Sahara. Seven depressions within the desert - Siwa, Qattara, Fayum, Bahariya, Farafra, Dakhla, and Kharga - may represent parts of old drainage systems with deflation, extensive erosion, and possibly, some tectonic activity. Oases with freshwater exist in these depressions. Geological and geophysical investigations in the Qattara Depression indicate the presence of buried fluvial channels with southeast to northwest flow directions from the highland areas. The origin of these fluvial systems, as well as the origin of the depressions themselves, is still unresolved, and many ideas have been suggested. Moghra Lake at the northeastern tip of the Qattara basin may be a remnant of a larger paleolake, including the mouth of a paleo-river.

Khan, Shuhab D.; Fathy, Mohamed S.; Abdelazeem, Maha

2014-02-01

8

Mesozoic rift basins in western desert of Egypt, their southern extension and impact on future exploration  

SciTech Connect

Rift basins are a primary target of exploration in east, central, and west Africa. These intracratonic rift basins range in age from the Triassic to the Neogene and are filled with lagoonal-lacustrine sand-shale sequences. Several rift basins may be present in the Western Desert of Egypt. In the northeastern African platform, the Mesozoic Tethyan strand lines were previously interpreted to have limited southern extension onto the continent. This concept, based upon a relatively limited amount of subsurface data, has directed and focused the exploration for oil and gas to the northernmost 120 km of the Western Desert of Egypt. Recent well and geophysical data indicate a southerly extension of mesozoic rift basins several hundred kilometers inland from the Mediterranean Sea. Shushan/Faghur and Abu Gharadig/Bahrein basins may represent subparallel Mesozoic basins, trending northeast-southwest. Marine Oxfordian-Kimmeridgian sediments were recently reported from wells drilled approximately 500 km south of the present-day Mediterranean shoreline. The link of these basins with the Sirte basin to the southwest in Libya is not well understood. Exploration is needed to evaluate the hydrocarbon potential of such basins.

Taha, M.A. (Conoco, Cairo (Egypt))

1988-08-01

9

Pitted and fluted rocks in the Western Desert of Egypt - Viking comparisons  

NASA Technical Reports Server (NTRS)

The Western Desert of Egypt is one of the most arid regions on earth and is probably the closest terrestrial analog to the surface of Mars. An expedition to the area in 1978 revealed an abundance of quartzite and basalt rocks that have been pitted and fluted by wind erosion and deflation of the desert surface. These pitted rocks are internally homogeneous, show no internal holes or vesicles, and are considered an important but neglected type of ventifact. They bear a striking resemblance to the pitted and fluted rocks seen by the Viking Landers, rocks that have generally been interpreted as vesicular basalts only slightly modified by wind erosion. Wind tunnel studies of the air flow over and around nonstreamlined hand specimens from the Western Desert show that windward abrasion coupled with negative flow, secondary flow, and vorticity in a unidirectional wind can explain the complex arrays of pits and flutes. These field and laboratory observations suggest that the pitted rocks at the Viking Lander sites are also ventifacts, and thus the Martian surface may be far more wind eroded than previously thought.

Mccauley, J. F.; Breed, C. S.; Grolier, M. J.; El-Baz, F.; Whitney, M. I.; Ward, A. W.

1979-01-01

10

Age and isotopic constraints on pleistocene pluvial episodes in the Western Desert, Egypt.  

SciTech Connect

North Africa has undergone drastic climatic changes over the past several hundred thousand years. The timing of humid intervals called pluvials was investigated by uranium-series disequilibrium dating of travertines from the Kurkur Oasis, Western Desert, Egypt. The youngest and best dated travertines (70-160 ka) are found in Wadi Kurkur and include spring and lacustrine units exposed as 2 to 3 m high terraces. Travertines having an age of approximately 191-220 ka are exposed by differential erosion as linear mounds produced by spring systems over fracture zones in ancient wadis. The oldest travertines, having ages >260 ka, are extensive, cap limestone units above the oasis, and were deposited in paludal and lacustrine environments. Oxygen isotope ratios were measured for the wadi travertines ({delta}{sup 18}O values ranging from 16.7 to 19.1{per_thousand} SMOW) and for spring mound travertines (18.5-20.5{per_thousand}). Equilibrium oxygen isotope fractionation calculations indicate that the Kurkur travertines were deposited from waters having {delta}{sup 18}O values similar to ancient Western Desert groundwaters ({approx} -11{per_thousand}). The ages of the travertines correspond to times of monsoonal maxima, eustatic sea level high stands and interglacial maxima. Rainfall producing these groundwaters (and travertines) was significantly fractionated during atmospheric transport, in contrast to modern meteoric waters (-2.09{per_thousand}), implying a distant source for the pluvial waters. Increased precipitation, recharge of Western Desert groundwaters, and resultant travertine deposition are interpreted to be consequences of Milankovitch insolation cycle forcing, through enhanced Atlantic and Indian Ocean monsoons during interglacial time periods.

Crombie, M. K.; Arvidson, R. E.; Sturchio, N. C.; El Alfy, Z.; Abu Zeid, K.; Environmental Research; Washington Univ.; Egyptian Geological Survey and Mining Authority

1997-01-01

11

Evidence for a ˜ 200 100 ka meteorite impact in the Western Desert of Egypt  

NASA Astrophysics Data System (ADS)

In this study, we present evidence, in the form of unusual silicate glasses, for a meteorite impact event ˜ 200-100 ka in the Dakhleh Oasis, Western Desert, Egypt. These glasses, known locally as Dakhleh Glass, were derived from the shock melting of a series of unconsolidated sediments underlain by interbedded carbonates, sandstones and phosphate-rich lithologies. Hypervelocity impact in to a volatile-rich target resulted in the production of impact glasses with CaO and Al 2O 3 contents of up to ˜ 25 and 18 wt.%, respectively. Other notable properties include the presence of globules of immiscible calcite and pyrrhotite melt phases, shattered quartz grains, and fragments of silicified plant matter. Dating of geoarchaeological artefacts associated with the Dakhleh Glass support preliminary 40Ar/ 39Ar data, indicating a ˜ 200-100 ka age for the impact event. Geoarchaeological evidence indicates that archaic Homo sapiens and early modern humans continually inhabited this region of the Western Desert during this period. While it is unclear at present whether the Dakhleh Glass was formed during a cratering event or a large aerial burst, the effect on the environment and inhabitants of Dakhleh would have been catastrophic.

Osinski, Gordon R.; Schwarcz, Henry P.; Smith, Jennifer R.; Kleindienst, Maxine R.; Haldemann, Albert F. C.; Churcher, Charles S.

2007-01-01

12

Precipitation Source Inferred from Stable Isotopic Composition of Pleistocene Groundwater and Carbonate Deposits in the Western Desert of Egypt  

Microsoft Academic Search

An Atlantic source of precipitation can be inferred from stable isotopic data (H and O) for fossil groundwaters and uranium-series-dated carbonate spring deposits from oases in the Western Desert of Egypt. In the context of available stable isotopic data for fossil groundwaters throughout North Africa, the observed isotopic depletions (?D ?72 to ?81‰; ?18O ?10.6 to ?11.5‰) of fossil (?32,000

Mohamed Sultan; Neil Sturchio; Fekri A. Hassan; Mohamed Abdel Rahman Hamdan; Abdel Moneim Mahmood; Zeinhom El Alfy; Tom Stein

1997-01-01

13

Reconstructing Quaternary pluvial episodes and paleohydrology using travertines from Egypt's Western Desert  

NASA Astrophysics Data System (ADS)

Quaternary climate in North Africa was marked by multiple wet periods overprinting extreme aridity, but pluvial drivers, as well as their timing and geographic extent, are poorly constrained. We address these factors in the first comprehensive analysis of travertine from Egypt's Western Desert, which represents a unique and under-utilized record of paleoclimate and paleohydrology. We infer large-volume travertine mound deposition along faults near the area's central limestone plateau to reflect times of high discharge (high groundwater head) from springs of the Nubian aquifer, likely associated with so-called Green Sahara pluvial episodes. Similarly, we assume that travertine platforms in depressions (oases) represent related marsh and lake deposition, including a widespread late Cenozoic dolostone of probable lacustrine origin in Farafra Oasis, which needs additional mapping. We present the results of uranium-series analysis of travertines from oasis areas spanning a north-south gradient through the Western Desert; we dated the tops and bottoms of inset deposits at different wadi (wash) elevations to resolve the inception and termination of high spring heads/pluvials as well as regional aggradation or incision patterns. Our dates, combined with published literature ages, suggest wet intervals around 100-115, 125-140, 180-200, 350-360, 450, and 600 ka. Heights of inset terrace travertines in wadis are potentially correlative between sites and are seen as approximately 5, 10, and 25 m above the modern wadi levels. Assuming that paleohydrological changes reflect paleoclimate changes, we examine correlations between times of travertine deposition, relative to glacial cycles or to more specific orbital forcings, acting on the North African summer monsoon. Initial comparison of travertine occurrence to glacial cycles shows no obvious correlation, although there are major travertine deposition episodes at important paleoclimate transitions such as MIS 6 to 5, 7 to 6, and 11 to 10. Perhaps the best preliminary association is to orbital forcing, particularly precession, consistent with the hypothesis that orbital forcing is a driver of the North African monsoon and thus pluvials.

Jimenez, G.; Crossey, L. J.; Karlstrom, K. E.; Ricketts, J. W.; Tafoya, A. J.; Anan, T.; Mohammed, A.; Asmerom, Y.; Polyak, V.; Farouk, S.

2012-12-01

14

Remote Sensing and Shallow Geophysical Investigations on Moghra Lake in Northeastern Qattarra Depression, Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

The Western Desert of Egypt encompasses two thirds of the land area of Egypt and constitutes one of the driest regions of the Sahara. This desert has seven depressions; Siwa, Qattara, Fayium, Bahariya, Farafra, Dakhla and Kharga. These depressions may be the manifestation of old drainage basins with extensive erosion and possibly some tectonic activity. Several oases with freshwater can be found in these depressions. Geological and geophysical investigations in Qattara Depression indicate several buried fluvial channels with flow direction from highlands in southeast to northwest. Moghra Lake at the northeastern tip of Qatarra basin may be a small remnant of a larger paleo-lake including the mouth of a paleo-river. This study probed this area for presence of buried channels that may have fed the larger Moghra paleo-lake. We have used ALOS - PALSAR radar remote sensing data to identify the surface features in this region, such as channels, channel fills, and fractures. In addition, dual polarization PALSAR data (HV, HH) allowed analysis of the near surface geology and assisted in delineating areas of interest for GPR surveys. GPR data along 2D profiles were acquired using the GSSI SIR-3000 system with a 400 MHz antenna that provided images to approximately three meters in depth. All the GPS data were processed using RADAN 6.6 software. A conventional processing flow was used for data processing: The positional correction tool removed the air wave. A range-gain balanced the amplitudes and a final band-pass (50 kHz to 500 kHz) filter was applied to the data. Deconvolution was also applied for highlighting the finer details. In addition, spatial filters were used to attenuate continuous vertical noise. The migrated sections of GPR identified a major paleochannel distributary with two minor channels at the margins. The bedrock of the studied area consists of the Lower Miocene Moghra Formation (sandstone and shale intercalations). The area around the present lake is covered by about 2 m of lacustrine sediments of post-Miocene age in the east side and by recent eolian dunes in the west. These sediments are characterized by shallowing upward, horizontal to cross-bedded with an unconformity in between. The eastern end of the paleochannel surveyed by GPR is covered by recent sand dunes followed by an ephemeral stream that feeds the current lake. Field observations suggest that the movement of sand dunes in the northeast direction may have blocked the paleo-channel. A two meters deep trench was dug to confirm the GPR findings. Regional gravity mapping of this area also shows major gravity anomalies. More work is planned to carry out additional high resolution potential field surveys in conjunction with remote sensing and GPR studies to understand the paleo-drainage of this area. Identifying the exact track of the paleo-channels will help reconstructing of paleo drainage of this region and may help in mapping groundwater, this will be very important for the development of this rapidly expanding desert area.

Khan, S. D.; Fathy, M. S.; Azeem, M. A.

2012-12-01

15

Origin of the gypsum-rich silica nodules, Moghra Formation, Northwest Qattara depression, Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

Gypsum rich-silica nodules appear in two shale horizons of the Moghra Formation (early Miocene) northwestern Qattara Depression, Western Desert, Egypt. These nodules are gray to milky white in colour, mostly botroidal and rose-like in shape and range in diameter from 2 to 7.5 cm. The silica nodule-bearing shale is composed mainly of smectite with a little minor kaolinite. The silica nodules consist mainly of quartz and are composed of gypsum-free matrix and gypsum-rich megacrystalline quartz. The matrix consists of microflamboyant quartz (less than 36 ?m in diameter) and chalcedony. The megacrystalline quartz occurs as lenticular and prismatic forms (length: 90-250 ?m; width: 30-90 ?m). The microprobe, petrographic and SEM examinations confirmed the occurrence of gypsum relics (diameter; 2-16 ?m) within the megacrystalline quartz. The chalcedony and mosaic microcrystalline quartz occurs as pore-lining and pore-filling cements. The structure of the silica nodules begins with quartzine in its outer rim, then gypsum-free microcrystalline quartz in the middle part and ends with gypsum-rich lenticular to prismatic megaquartz in the center. Field study, petrographic examination and microprobe analysis reveal that the silica nodules were formed by silicification of precursor gypsum nodules deposited in a marginal sabkha environment under an arid climate. The silicification selectively affected the gypsum nodules rather than the surrounding shale and occurred both through gypsum replacement and void filling. Transformation of isopachous chalcedony into mosaic microcrystalline quartz also occurred. The texture of the silica minerals reflects the different physico-chemical conditions under which they crystallized. Spherical nodules grew chiefly by the diffusive supply of the silica, and elongated ones grew by pore water advection. The integrated effect of climate, pH, salinity, crack systems within the sediment and oscillation in the groundwater level and its chemical composition contributed to the formation of the nodules.

El Khoriby, Essam M.

2005-06-01

16

Palynostratigraphic Studies of the Lower Cretaceous Sediments, Alamein Formation, Bahrein-1 Well in the Northern Part of the Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

Palynostratigraphic studies of the Lower Cretaceous sediments, Alamein Formation, Bahrein-1 well in the northern part of the Western Desert, Egypt, have been carried out from an evolutionary and geological viewpoint. The palynoflora principally consists of pteridophytes, gymnosperms and some rare angiosperm pollen. The microflora shows that the palaeoenvironments were favorable for different kinds of plants. The recovered microflora, therefore, indicates an Early Aptian age and can be extended to the Early Albian. The palynological data revealed that the North Western Desert (N.W.D.) of Egypt belongs to the North Gondwana phytogeoprovince in the Early Cretaceous.

Lashin, Gamal M. A.

17

Palynological, palynofacies, paleoenvironmental and organic geochemical studies on the Upper Cretaceous succession of the GPTSW-7 well, North Western Desert, Egypt  

Microsoft Academic Search

The present study of the Abu Roash and Bahariya formations in well GPTSW-7 refines our understanding of the subsurface Cretaceous of the north Western Desert of Egypt. Our investigations are based on the palynological analyses of 71 cuttings samples, of which 24 have also been analyzed for geochemistry, in addition to 3 sidewall cores analyzed for vitrinite reflectance (Ro).Four palynological

Salah Y. El Beialy; Haytham S. El Atfy; Michael S. Zavada; Essam M. El Khoriby; Ramadan H. Abu-Zied

2010-01-01

18

Sedimentary cover in the South Western Desert of Egypt as deduced from Bouguer gravity and drill-hole data  

NASA Astrophysics Data System (ADS)

The Western Desert, Egypt includes the major groundwater aquifer in the country. It is apart from the Major Sahara Nubian Aquifer which is present in Sudan, Chad, Egypt and Libya. Thickness of this aquifer is changed laterally from south to north and also from west to east. The changes may structurally or litheologicalley control. The present study is focused on using of Bouguer gravity anomaly mapped at a scale of 1:500,000 and the lithological logs of about 120 deep wells used to determine the thickness of the sedimentary sequence containing the main Nubian sandstone water aquifer in important area of Egypt. The area is located in the southern part of the Western Desert bounded by the latitudes 22°00'-26°30'N, and longitudes 28°30'-33°00'E. The predominant structures affecting the basement rocks and the sedimentary cover were traced and analyzed. The gravity stripping approach was applied to eliminate the gravity effects caused by sedimentary sequence and to separate density anomalies within the sedimentary fill from the influence of rocks at deeper levels in the crystalline crust. The study indicated that the surface of the basement rocks is highly rugged and mostly controlled by structures which have a direct effect on thickness variation of the sedimentary cover all over the area. Regionally the area is characterized by two major intracratonic basins (the Dahkla Basin and the Nile valley Basin) separated by a NE-SW trending swell of the Kharga uplift and bounded at the south by the Oweinat-Bir Safsaf-Aswan uplift. These major tectonic units are controlled by fault structures trending in N-S, E-W, NE-SW, NW-SE, which cut the basement rocks and extend upward in the sedimentary cover. The maximum thickness of sandstone formations is recorded at west Oweinat, west Kurkur, southwest of Aswan, Gramashin, Dakhla oasis and some localities west of Sohag and Qena towns. At these localities the thickness ranges between 600 and 900 m. As this formation is the main water aquifer in the study area, therefore these localities are characterized by the presence of big amount of ground water. Accordingly, these areas must take the priority in the sustainable development programs of southern Egypt.

Senosy, M. M.; Youssef, M. M.; Abdel Zaher, M.

2013-06-01

19

SAR Remote Sensing of Buried Faults: Implications for Groundwater Exploration in the Western Desert of Egypt  

NASA Astrophysics Data System (ADS)

The hydrological setting of a desert plain area located in Egypt, west of Aswan city, is still not well understood, and thus, its groundwater potential remains largely unknown. Images from the ALOS/PALSAR L-band sensor have been used to detect and delineate the subsurface structures in this area. Linear, elliptical and circular polarization transformations were applied to the ALOS/PALSAR full polarimetric data by changing the orientation angle (?°) and elliptical angle (?°). The circular polarization (? = 0° and ? = 45°) proved to be the best transformation for revealing buried faults in various strike directions, which have not been reported in the last version of the official geologic map of this area. Such derived circular polarization images were further enhanced by applying the Optimal Polarization Contrast Enhancement method. The moisture content ( ? S ) of the study sites was generally low, with an average of roughly 0.01%. The average Root Mean Square Height (hRMS) of the surface roughness was also low with 0.01 cm across all sites. The relative dielectric constant (? r ) of the sand in the study area produced a very low value of 3.04. The effects of ? S , ? r and hRMS on the radar backscattered signals turned out to be very low, thus providing, optimal conditions for L-band to penetrate relatively deeply. Moreover, 21 GPR profiles were acquired using 270 MHz shielded antennas to validate the radar remote sensing results. These GPR profiles reveal obvious offsets in the subsurface stratigraphy suggesting that such highly fractured zones are possibly favorable zones for groundwater accumulation.

Gaber, Ahmed; Koch, Magaly; Helmi Griesh, M.; Sato, Motoyuki

2011-12-01

20

Jurassic-Cretaceous (Bathonian to Cenomanian) palynology and stratigraphy of the West Tiba-1 borehole, northern Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

Land-derived pollen and spores and marine dinoflagellate cysts were extracted from the Jurassic and Cretaceous sediments of the West Tiba-1 borehole, northern Western Desert, Egypt, On the basis of the recovered palynomorphs, of known stratigraphical significance, the following stages were assessed: Bathonian-Oxfordian (Middle-Late Jurassic) and Hauterivian, Aptian-Early Albian, Late Albian-Early Cenomanian, Early Cenomanian and Late Cenomanian (Early-Middle Cretaceous). No palynomorphs diagnostic for the Berriasian, Valanginian and Barremian stages (Early Cretaceous) were depicted. Based on the nature and composition of the identified palynomorph content, five informal palynomorph assemblage zones were recognised. These are: the Gonyaulacysta jurassica-Korystocysta kettonensis Assemblage Zone (PI, Bathonian-Oxfordian), Ephedripites-Aequitriradites verrucosus Assemblage Zone (PII, Hauterivian), Afropollis jardinus-Duplexisporites generalis-Tricolpites Assemblage Zone (PIIl, Aptian-Early Albian), Nyssapollenites-Elaterosporites Assemblage Zone (PIV, Late Albian-Early Cenomanian) and Assemblage Zone PV (Early-Late Cenomanian). The latter zone was differentiated into two subzones, namely the Classopollis brasiliensis-Elaterosporites klaszii Assemblage Subzone (PVa, Early Cenomanian) and Afropollis kahramanensis-Triporates Assemblage Subzone (PVb, Late Cenomanian). The time stratigraphy of the studied interval was revised. The occurrences and types of the dinoflagellate cysts, extracted from the studied succession, reflect a general shallow (shelf) marine pal?oenvironment.

Mahmoud, Magdy S.; Moawad, Abdel-Rahim M. M.

2000-02-01

21

Precipitation source inferred from stable isotopic composition of Pleistocene groundwater and carbonate deposits in the western desert of Egypt.  

SciTech Connect

An Atlantic source of precipitation can be inferred from stable isotopic data (H and O) for fossil groundwaters and uranium-series-dated carbonate spring deposits from oases in the Western Desert of Egypt. In the context of available stable isotopic data for fossil groundwaters throughout North Africa, the observed isotopic depletions ({delta}D -72 to -81{per_thousand}; {delta}{sup 18}O -10.6 to -11.5{per_thousand}) of fossil ({ge}32,000 yr B.P.) groundwaters from the Nubian aquifer are best explained by progressive condensation of water vapor from paleowesterly wet oceanic air masses that traveled across North Africa and operated at least as far back as 450,000 yr before the present. The values of {delta}{sup 18}O (17.1 to 25.9{per_thousand}) for 45,000- to >450,000-yr-old tufas and vein-filling calcite deposits from the Kharga and Farafra Oases are consistent with deposition from groundwaters having oxygen isotopic compositions similar to those of fossil groundwaters sampled recently at these locations.

Sultan, M.; Sturchio, N.; Hassan, F. A.; Abdel, M.; Hamdan, R.; Mahmood, A. M.; Alfy, Z. E.; Stein, T.; Environmental Research; Univ. Coll. London; Cairo Univ.; Ain Shams Univ.; Egyptian Geological survey and Mining Authority; Washington Univ.

1997-01-01

22

3D slicing of radiogenic heat production in Bahariya Formation, Tut oil field, North-Western Desert, Egypt.  

PubMed

A 3D block of radiogenic heat production was constructed from the subsurface total gamma ray logs of Bahariya Formation, Western Desert, Egypt. The studied rocks possess a range of radiogenic heat production varying from 0.21 ?Wm(-3) to 2.2 ?Wm(-3). Sandstone rocks of Bahariya Formation have higher radiogenic heat production than the average for crustal sedimentary rocks. The high values of density log of Bahariya Formation indicate the presence of iron oxides which contribute the uranium radioactive ores that increase the radiogenic heat production of these rocks. The average radiogenic heat production produced from the study area is calculated as 6.3 kW. The histogram and cumulative frequency analyses illustrate that the range from 0.8 to 1.2 ?Wm(-3) is about 45.3% of radiogenic heat production values. The 3D slicing of the reservoir shows that the southeastern and northeastern parts of the study area have higher radiogenic heat production than other parts. PMID:23291561

Al-Alfy, I M; Nabih, M A

2013-03-01

23

Electric fabric of Cretaceous clastic rocks in Abu Gharadig basin, Western Desert, Egypt  

Microsoft Academic Search

Measuring the petrophysical properties of sedimentary rocks in three-dimensions (3-D) has a high priority for interpretation of their physical behaviour. The present work attempts to study the 3-D electric behaviour of the Upper Cretaceous sandstones and clayey sandstones in the Abu Gharadig basin, Egypt. These rocks belong to the Betty, Bahariya, and Abu Roash Formations. The apparent electrical resistivity (Ro)

Bassem S. Nabawy; Tarek Y. M. ElHariri

2008-01-01

24

Cosmogenic, radiogenic, and stable isotopic constraints on groundwater residence time in the nubian aquifer, western desert of egypt  

SciTech Connect

Measurements of radiochlorine ({sup 36}Cl), radiogenic noble gases ({sup 4}He and {sup 40}Ar), and stable chlorine isotope ratios were obtained to assess the residence time of groundwater in the Nubian Aquifer of the Western Desert of Egypt. Measured {sup 36}Cl/Cl ratios yield apparent residence times from {approx}0.2 to 1.2 x 10{sup 6} years in the deep (600-1200 m) groundwater (assuming constant Cl) and {le} 0.16 x 10{sup 6} years in the shallow (<600 m) groundwater. Values of {delta}{sup 37}Cl in the groundwater strengthen the application of the {sup 36}Cl dating method by constraining Cl sources and identifying groundwater mixing. Dissolved gases were measured in some of the deep groundwater samples. Measured {sup 4}He concentrations indicate accumulation of radiogenic {sup 4}He that is qualitatively consistent with the age progression indicated by the {sup 36}Cl/Cl ratios, but the flux of external {sup 4}He from the underlying crust has not been quantified and is not constant throughout the aquifer. Concentrations of {sup 40}Ar range from 3.3 to 6.7 x 10{sup -4} ccSTP/g and indicate excess air incorporation at recharge. Measured {sup 40}Ar/{sup 36}Ar ratios do not exceed the atmospheric ratio. A two-dimensional numerical hydrodynamic transect of the aquifer was modeled from the area of the Uweinat Uplift to the northern Bahariya Oasis. Predicted groundwater velocities in the deep portion of the aquifer are 0.5-3.5 m/yr with groundwater residence times up to 9 x 10{sup 5} years; residence times up to 1.3 x 10{sup 6} years are predicted in the confining shale. Aquifer properties are estimated by using the model to fit the measured {sup 36}Cl/Cl ratios. Under these conditions, hydrodynamic residence times are within about 30 percent of those calculated from {sup 36}Cl when mixing of Cl{sup -} is accounted for in the highest-Cl{sup -} deep groundwaters. By mutually calibrating multiple methods (hydrodynamic, {sup 36}Cl, and {sup 4}He), a consistent picture of the Nubian Aquifer has emerged in which lateral flow from a southern recharge area dominates the deep horizons, while shallow horizons contain younger, autochthonous recharge.

Patterson, Leslie J.; Sturchio, Neil C.; Kennedy, B.Mack; van Soest, Matthias C.; Sultan, Mohamed; Lu, Zheng-Tian; Lehmann, Bernhard; Purtschert, Roland; El Alfy, Zeinhom; El Kaliouby, Baher; Dawood, Yehia; Abdallah, Ali

2004-06-01

25

A Study of Hydrogeological Conditions of the Nubian Sandstone Aguifer in the Area between Abu Simbel and Toschka, Western Desert, Egypt.  

NASA Astrophysics Data System (ADS)

A Study of Hydrogeological Conditions of the Nubian Sandstone Aquifer in the Area between Abu Simbel and Toschka, Western Desert, Egypt. By K. A. Dahab*, A. M. Ebraheem**, and E. El Sayed*** *Geology Department, Faculty of Science, Menofia University, Shibin El Kom, Egypt. ** Geology Department, Faculty of Science, Assiut University, Assiut, Egypt. *** Geology Department, Faculty of Science, Minia University, Minia, Egypt. The Nubian Sandstone Aquifer in the area between Toschka and Abu Simbil is small portion of the very well known Nubian Sandstone Aquifer System in the Eastern Sahara, which covers the entire area of southwest Egypt, southeast Libya, northeast Chad, and northern Sudan. Toscha area is currently the site of intensive drilling and development for a huge land reclamation project. The drilling information was used to study the hydrogeological setting of the Nubian Sandstone aquifer in the area. The obtained results indicate that the lithological characteristics and tectonic setting is strongly affecting the groundwater flow pattern as well as the aquifer potentiality of the nubian sandstone aquifer in the area. The aquifer potentiality in this area is low if compared to that of east Oweinat or Dakhla areas. The aquifer is mainly composed of hard ferruginous sandstone with great shale and clay intercalation with a thickness ranging from 140 to 230 meters. Groundwater in this aquifer belongs to fresh to slightly brackish type (salinity is ranging from 240 to 1300 ppm). Ion dominance ordering reveals that sodium cation is mostly predominating over calcium and magnesium whereas chloride is predominant over sulfate and bicarbonate. The groundwater is related to meteoric origin. The high concentration of sodium, chloride, and sulfates reflect leaching and dissolution processes of gypsiferous shales and clay as well as long residence time of water.

Dahab, K. A.; Ebraheem, A. M.; El Sayed, E. A.

2001-05-01

26

Hydrogeological aspects and environmental concerns of the New Valley Project, Western Desert, Egypt, with special emphasis on the southern area  

SciTech Connect

The New Valley Project has been given much attention in the past 20 years especially from the hydrogeological point of view concerning groundwater utilization for the reclamation of a large area of the Western Desert. Lithological, petrophysical, and petrographical studies were conducted on four wells south of Beris Oasis. The Nubian sandstones in the area south of Beris Oasis contain hematitic stains and/or fine granular authigenic hematite, thin laminae of brown ferruginous quartzite is also recorded denoting oxidizing conditions in the basin of deposition. Thin streaks of carbonaceous shales are met with in different depths to the south of Beris area, may be taken to denote oscillations in the sea level and accordingly its depths, and are responsible for the change in the oxidation-reduction potential during the deposition of the corresponding beds. Petrographic examination of a thin section of the subsurface Nubia sandstones in the South of Beris Oasis showed that the lithified rocks fail into three types depending on the nature of cement being, silicious or ferruginous, and on the amount of primary matrix, which at present is reorganized into iron oxides, microquartz, and muscovite flakes, thus reaching the phyllomorphic stage of diagenesis. Rounding of the quartz grains shows that transportation had a minor effect on the grain morphology and favor a fluviatile transporting agent.

Assaad, F.A. (P.E. LaMoreaux and Associates, Tuscaloosa, AL (United States))

1988-12-01

27

Jurassic-Cretaceous palynomorphs, palynofacies, and petroleum potential of the Sharib-1X and Ghoroud-1X wells, north Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

Palynomorph and palynofacies analyses have been performed on 93 cutting samples from the Jurassic Masajid Formation and Cretaceous Alam El Bueib, Alamein, Dahab, Kharita, and Bahariya formations in the Sharib-1X and Ghoroud-1X wells, north Western Desert, Egypt. Two palynological biozones are proposed for the studied interval of the Sharib-1X well: the Systematophora penicillata-Escharisphaeridia pocockii Assemblage Zone (Middle to Late Jurassic) and the Cretacaeiporites densimurus-Elateroplicites africaensis-Reyrea polymorpha Assemblage Zone (mid-Cretaceous: late Albian to early Cenomanian). Spore coloration and visual kerogen analysis are used to assess the thermal maturation and source rock potential. Mature oil prone to overmature gas prone source rocks occur in the studied interval of the Sharib-1X well, whereas highly mature to overmature gas prone source rocks occur in the studied interval of the Ghoroud-1X well. Palynofacies and palynomorph assemblages in both wells reflect shallow marine conditions throughout the Jurassic and the late Albian and early Cenomanian. During these times, warm and dry climatic conditions prevailed. The Cretaceous palynomorph assemblages of the Sharib-IX well correlate with the Albian-Cenomanian Elaterates Province of Herngreen et al. (1996).

Zobaa, Mohamed K.; El Beialy, Salah Y.; El-Sheikh, Hassan A.; El Beshtawy, Mohamed K.

2013-02-01

28

Calcretes and palustrine carbonates in the Oligo-Miocene clastic-carbonate unit of the Farafra Oasis, Western Desert, Egypt: Their origin and paleoenvironmental significance  

NASA Astrophysics Data System (ADS)

The origin and paleoenvironmental significance of the calcretes and palustrine carbonates in the Oligo-Miocene clastic-carbonate unit that outcrops at the eastern sector of the Farafra Depression (Western Desert, Egypt) have been discussed based on field and petrographic investigations. The calcretes-palustrine carbonates assemblage occurs above a siliciclastic/distal alluvial-floodplain facies. The calcretes represent the transition from the underlying siliciclastic/distal alluvial-floodplain facies to the overlying palustrine carbonates. The calcrete-host rocks are muddy sandstones and sandy mudrocks. This study reveals the occurrence of groundwater calcretes with an upward gradational maturity pattern, ranging from incipient to nodular and to massive calcretes. The calcretes micromorphological analysis suggests that they were originated in vadose and phreatic diagenetic environments by groundwater through evaporation, degassing with no biological activity. The palustrine carbonates are also recognized above the calcrete horizons. They occur in the form of micritic limestones displaying different features that indicate their modifications during pedogenesis and subaerial exposure. These features include clotted-peloidal texture, fenestral fabric, mottling, pseudo-brecciation, desiccation cracks, pseudomicrokarst, root traces and silicification of the lime mud. The calcretes-palustrine carbonates assemblage records a progressive decrease in the terrigenous supply and a continuous rise of the groundwater table associated with local subsidence in a semi-arid to sub-humid climate. A model is suggested for the development of calcretes and palustrine carbonates in the study area.

Wanas, H. A.; Soliman, H. E.

2014-07-01

29

Characterization of magnetic spherical fractions in sand deposits for interpretation of environmental change around the El- Zayyan temple, Kharga Oasis, Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

Desertification in North Africa has rapidly advanced over the last 6,000 years. Such environmental changes began in the Early Dynastic Period of Egypt (4200 - 3150 BC), and the occupation of Achaemenid Persian and Roman cultures in Egypt occurred under even drier climates. Kharga is the largest oasis of the five oases, located in the western desert of Egypt that contains a treasure trove of archaeological resources. This oasis has been highlighted to promote resource exploration and development of archaeological tourism since the 1980's. The El-Zayyan temple is located 27 km south of the central Kharga oasis. Zayyan was once called 'Tchonemyris', which has connection with the means of 'huge well' in Greek. Although major portions of the temple were rebuilt in 140 AD during the rule of the Roman Emperor Antoninus Pius, this temple is considered to be originally built in the Ptolemaic period (4c-1c BC). It is likely that the area had a sufficient water supply in the past as the El-Zayyan temple stands at the lowest point (-18 m a.s.l.) in the Kharga oasis. Furthermore, the El-Ghueita temple that stands on a hill top at 68.5 m a.s.l., 4 km northward from the El-Zayyan temple, has given name that means 'beautiful garden' in Greek. From these facts, we can imagine that the past landscape of this area contained green surroundings. The El-Ghueita temple was well known as a production centre of high quality wine since the mid-Dynastic age (2050 -1786 BC). As this area is currently arid, it is expected that there were irrigation facilities to maintain the vast farm land during the ancient period. To deepen our knowledge of how people developed their technologies and conducted their life within the natural environment of a drastic drying period, understanding the process of environmental change on a region scale is necessary. The aim of this study was to extract proxies from sand deposits in the western desert area to estimate the change in the environment. We examined the sand layers with a focus on the spherical magnetic fractions having relations with accumulation of free iron oxides, condition of water and microbial activities. The study sites were located west of the El-Zayyan temple, and six and seven samples were collected every 10 cm from the two sand profiles, Zy-R and Zy-6, respectively. AMS 14C dating was conducted using fine fractions of an organo-mineral complex; date ranges 5,000-8,400 yBP and 5,500-7,800 yBP were assigned to Zy-R and Zy-6, respectively. Spherical fractions, separated into six colored-types, were extracted using a neodymium magnet, and then characterized by SEM observation, EDX elemental analysis (FE-SEM S4700, Hitachi, Genesis, EDAX), and X-ray micro-crystal structural analysis (D8-Discover, Bruker axs) to discuss their origins. The vertical change in the density of each fraction by weight and counts in sand revealed the environmental change.

Watanabe, Makiko; Koizumi, Natsuko; Kato, Sayuri; Kikuchi, Ryohei; Kamei, Hiroyuki

2014-05-01

30

Substance geology of the western desert in Egypt and Sudan revealed by Shuttle Imaging Radar (SIR-A)  

NASA Technical Reports Server (NTRS)

A correlation of known archaeologic sites with the mapped locations of the streamcourses is expected and may lead to new interpretations of early human history in the Sahara. The valley networks, faults, and other subjacent bedrock features mapped on the SIR-A images are promising areas for ground water and mineral exploration. Additionally, the analogies between the interplay of wind and running water in the geologic history of the Sahara and of Mars are strengthened by the SIR-A discoveries of relict drainage systems beneath the eolian veneer of Egypt and Sudan.

Breed, C. S.; Schaber, G. G.; Mccauley, J. F.; Grolier, M. J.; Haynes, C. V.; Elachi, C.; Blom, R.; Issawi, B.; Mchugh, W. P.

1983-01-01

31

Structural and tectonic evolution of El-Faiyum depression, North Western Desert, Egypt based on analysis of Landsat ETM+, and SRTM Data  

Microsoft Academic Search

False color Landsat ETM+ (bands 7, 4, 2 in RGB) and SRTM images of the El-Faiyum depression, Egypt, highlights major NE-SW\\u000a faults and other lineaments trending NW-SE and N-S. Airborne magnetic data reveal some E-W subsurface faults which are not\\u000a recognized on Landsat ETM+ and SRTM images. Ratio images (5\\/7, 3\\/1, 4\\/3) and (5\\/7, 5\\/1, 4) were used for lithological

Timothy M. Kusky; Talaat M. Ramadan; Mahmoud M. Hassaan; Safwat Gabr

2011-01-01

32

Chemical and isotopic constraints on the origin of Wadi El-Tarfa ground waters, Eastern Desert, Egypt  

Microsoft Academic Search

We evaluated the use of the renewable ground water resources of the Eastern Desert to develop sustainable agriculture in Upper Egypt, an alternative that could alleviate some of Egypt's dependence on water from the Nile River. Ground water from shallow aquifers in the Eastern Desert of Egypt, near the intersection of Wadi El-Tarfa and the Nile River, was analyzed for

M. Sultan; N. C. Sturchio; Y. Abdel Hady; M. El Anbeawy

2000-01-01

33

MODELING POPULATION VIABILITY FOR THE DESERT TORTOISE IN THE WESTERN MOJAVE DESERT1  

Microsoft Academic Search

The desert tortoise is a threatened species living in the deserts of the Amer- ican Southwest. Using size-structured demographic models, we analyzed the status of the tortoise in the Western Mojave desert and evaluated the effectiveness of possible manage- ment measures. Our demographic analyses agree with the trends reported by field censuses in showing rapid population decline. Importantly, simulations that

DANIEL DOAK; PETER KAREIVA

1994-01-01

34

77 FR 26950 - Designation of Areas for Air Quality Planning Purposes; California; Western Mojave Desert Ozone...  

Federal Register 2010, 2011, 2012, 2013

...Quality Planning Purposes; California; Western Mojave Desert Ozone Nonattainment Area...State of California to reclassify the Western Mojave Desert ozone nonattainment area...California located within the boundaries of the Western Mojave Desert area in the same...

2012-05-08

35

Petrogenesis and tectonic setting of late Precambrian ensimatic volcanic rocks, central eastern desert of Egypt  

Microsoft Academic Search

Early stages in the geologic evolution of the central eastern desert of Egypt (CED) reflect an ilatense episode of ensimatic volcanic activity similar to modern magmatism of the ocean floors and island arcs. This paper reports results from studies of the petrology and petrogenesis, and interprets the significance of these Late Precambrian volcanic rocks. A three-fold stratigraphy is preserved in

ROBERT JAMES STERN

1981-01-01

36

From platform to basin: the evolution of a Paleocene carbonate margin (Eastern Desert, Egypt)  

Microsoft Academic Search

In this study, progradation and the subsequent retrogradation of a late Paleocene isolated carbonate platform (Galala Mountains, Eastern Desert, Egypt) is demonstrated by variations of distinct facies associations from the platform margin in the north to the hemipelagic basin in the south. A combination of a sea-level drop and tectonic uplift at around 59 Ma (calcareous nannofossil biozone NP5) favored the

C. Scheibner; J. J. G. Reijmer; A. M. Marzouk; R. P. Speijer; J. Kuss

2003-01-01

37

Geochemistry and Petrogenesis of the Late Jurassic-Early Cretaceous Mansouri Ring Complex, Southeastern Desert, Egypt  

Microsoft Academic Search

The Mansouri Ring Complex is an eccentric mass (9 × 6 km) located in the extreme southwestern part of the Eastern Desert of Egypt. The complex exhibits a poorly defined ring structure and a limited variety of rock types: trachytes, alkali feldspar syenites and rhyolitic dykes. The rocks are hypersolvus, porphyritic and less commonly show trachytic textures. The complex has

S. A. El-nisr; G. M. Saleh

2001-01-01

38

Mercury dispersion patterns around El Sid-Fawakhir gold mine, Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

Mercury was determined in 98 stream sediment samples collected from the El Sid-Fawalhir Gold Mine area, Eastern Desert, Egypt, where Au-bearing quartz veins occur at the western contact of the Fawakhir granite pluton with serpentinites. The Hg contents vary over a wide range (<5-400 ppb). Mercury anomalies in stream sediments are clearly indicated over the mineralized zones, but the highest values are mostly observed in proximity to structural features such as faults and contact zones. Anomalous Hg contents also characterize sediments from some streams draining the central part of the granite body away from the mineralized zones. These anomalies may be interpreted as surface indications of blind ore deposits, or may be structural indicators. Bedrock samples collected along two profiles crossing the mineralized zone of the El Sid area show a Hg halo around the ore body. However, Hg is relatively more enriched in the stream sediments, and this may be attributed to adsorption of Hg by clay minerals.

El-Bouseily, Ahmed M.; Arslan, Ahmed I.; Ghoneim, Mohamed F.; Harraz, Hassan Z.

39

The photosynthetic pathway types of some desert plants from India, Saudi Arabia, Egypt, and Iraq  

Microsoft Academic Search

Plants collected from different habitats in the deserts of India, Saudi Arabia, Egypt, and Iraq were screened for their photosynthetic CO2-fixation pathways using d13C and dD values. The analyses comprised 128 species belonging to 108 genera and 46 families. Neither the C4 nor the CAM pathway was prevalent in the plant families analyzed except in Poaceae, where C4 metabolism absolutely

H. Ziegler; K. H. Batanouny; N. Sankhla; O. P. Vyas; W. Stichler

1981-01-01

40

Radioactive disequilibrium in the different rock types in Wadi Wizr, the Eastern Desert of Egypt  

Microsoft Academic Search

Remote sensing and radiometric survey techniques in the area between Qusier and Mersa Alam show variation of content of natural radioactivity in Wadi Wizr area, Eastern Desert of Egypt Gamma-ray, and laser fluorimetry were applied to measure the natural radioactivity content in representative content in representative samples from Wadi Wizr. The concentration of 226Ra ranged from 36 to 661Bqkg?1, while

Nagdya M Ibrahiem

2003-01-01

41

Soil seed bank in different habitats of the Eastern Desert of Egypt  

PubMed Central

The floristic composition and species diversity of the germinable soil seed bank were studied in three different habitats (desert salinized land, desert wadi, and reclaimed land) in the Eastern Desert of Egypt. Moreover, the degree of similarity between the seed bank and the above-ground vegetation was determined. The seed bank was studied in 40 stands representing the three habitats. Ten soil samples (each 25 × 20 cm and 5 cm depth) were randomly taken per stand. The seed bank was investigated by the seedling emergence method. Some 61 species belonging to 21 families and 54 genera were identified in the germinable seed bank. The recorded species include 43 annuals and 18 perennials. Ordination of stands by Detrended Correspondence Analysis (DCA) indicates that the stands of the three habitats are markedly distinguishable and show a clear pattern of segregation on the ordination planes. This indicates variations in the species composition among habitats. The results also demonstrate significant associations between the floristic composition of the seed bank and edaphic factors such as CaCO3, electrical conductivity, organic carbon and soil texture. The reclaimed land has the highest values of species richness, Shannon-index of diversity and the density of the germinable seed bank followed by the habitats of desert wadi and desert salinized land. Motyka’s similarity index between the seed bank and the above-ground vegetation is significantly higher in reclaimed land (75.1%) compared to desert wadi (38.4%) and desert salinized land (36.5%).

Gomaa, Nasr H.

2012-01-01

42

Holocene Paleoecology of the Western Tenere Desert, Niger, Africa  

Microsoft Academic Search

Multiple paleontological, sedimentological, and isotopic\\/ionic geochemical indicators permit reconstruction of the Holocene ecology of the western Tenere Desert (southern Sahara hyper-desert). Modern precipitation is highly erratic, averaging 25 mm yearly, and vegetative cover is negligible. From the early to middle Holocene, however, grassland-shrublands and seasonal to permanent lakes and wetlands predominated, supporting diverse limnic, riparian, and upland communities. Annual precipitation

P. C. Sereno; S. C. Caran; T. B. Housh

2007-01-01

43

Continental back-arc basin origin of some ophiolites from the Eastern Desert of Egypt  

NASA Astrophysics Data System (ADS)

Geochemical and petrographical data of three ophiolitic pillow metavolcanic occurrences from the central Eastern Desert of Egypt are presented. The investigated rocks show a subalkaline, tholeiitic affinity. Chemical data indicate that the metavolcanics have transitional within-plate basalt to island-arc basalt features, which are characteristics of basalts formed in ensialic back-arc basins. The association of the investigated ophiolites with volcanoclastic metasedimentary rocks of marine to continental facies is a further confirmation of their ensialic evolution. This suggestion, along with the geochronologic, isotopic and crustal growth rate evidences, revives interest in models that involve contribution from a pre-Pan-African continental crust at least in the southern part of the Egyptian Shield. Mixing between a depleted mantle-derived magma and an enriched crustal melt, a process similar to AFC (assimilation and fractional crystallization), is suggested for the evolution of the investigated rocks. This study provides evidence for formation of some ophiolites in the Eastern Desert of Egypt in continental (ensialic) back arc basins.

Farahat, E. S.; El Mahalawi, M. M.; Hoinkes, G.; Abdel Aal, A. Y.

2004-09-01

44

Egypt's petroleum geology: Good grounds for optimism  

SciTech Connect

In the past eight years 30 operators have discovered 25 fields in Egypt. While most have been in the Gulf of Suez, the Western Desert, Which covers two-thirds of the country, and the Nile Delta are also prospective. This study discusses Egypt's regional geology as well as the geology of the individual significant recent discoveries.

Abdine, A.S.

1981-12-01

45

Ground geophysical study for development and exploration of El Missikat radioactive minerals prospect, Central Eastern Desert of Egypt  

Microsoft Academic Search

The El Missikat area lies in the Eastern Desert of Egypt, 85 km west of Qena town. The area being studied is covered mainly by pink granite, quartz-diorite rocks and wadi deposits. The importance of the area originates from previous studies, including airborne geophysics, surface geology and mining geology which indicate that the area has features of radioactive mineralization at

E. M. Elkattan; H. S. Sadek; S. I. Rabie; H. I. Hassanein

1995-01-01

46

Elemental content of feldspar from Eastern Desert, Egypt, determined by INAA and XRF.  

PubMed

Instrumental neutron activation analysis (INAA) and HPGe detector gamma-spectroscopy were used to determine a total of 16 elements qualitatively and quantitatively for the first time from feldspar rock samples collected from Gabel El Dubb, Eastern desert, Egypt. The elements determined are (Na, Mg, K, Sc, Ga, Cr, Fe, Co, Zn, Nb, Ba, Ce, Eu, Hf, Th and U). The samples were properly prepared together with their standard reference material and simultaneously irradiated by thermal neutrons at the TRIGA Mainz research reactor at a neutron flux of 7x10(11)n/cm(2)s. XRF was also used. Comparison of the results obtained by both techniques showed good agreement for such elements as K, Na, Fe, Mg, Ba and Cr. PMID:20185321

El-Taher, A

2010-06-01

47

Sequence stratigraphy of the Cenomanian Galala Formation, north Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The sequence stratigraphic framework of the Cenomanian Galala Formation (north Eastern Desert, Egypt) is estimated on the basis of the Sedimentological and obtainable biostratigraphic data, in addition to the regional correlation of the studied sections. Five sequence boundaries are identified. The first sequence boundary separates between the Galala and Malha formations. The second, third and fourth sequence boundary exhibit a differentiated nature. It is noticed that such sequence boundaries in Gebel El-Zeit are mainly represented by paleosols and caliche, while those of the Northern Galala, Gebel Ataqa and Gebel Shabraweet are mostly typified by emergence horizons of dolomites and dedolomites. The fifth (last) sequence boundary separates the Galala Formation from the overlying El-Khashm Formation at Gebel El-Zeit, the Northern Galala and Gebel Ataqa and from Maghra El-Hadida Formation at Gebel Shabraweet.

Khalifa, M. A.; Abu El-Ghar, Mohamed S.; Helal, S. A.; Hussein, A. W.

2014-01-01

48

Natural radioactivity and rare earth elements in feldspar samples, Central Eastern desert, Egypt.  

PubMed

The pegmatite bodies of the Eastern Desert of Egypt are widely distributed especially along the Marsa-Alam-Idfu road. The Abu Dob area covers about 150km(2) of the Arabian Nubian shield at the central part of the Eastern Desert of Egypt. Most of the pegmatite is zoned; the zonation starts with milky quartz at the core followed by alkali feldspar at the margins. The feldspars vary in color from rose to milky and in composition from K-feldspar to Na-feldspar, sometimes interactions of both types are encountered. Thirteen feldspar samples were collected from different locations in the Abu Dob area for measuring the natural radioactivity of (238)U, (232)Th and (40)K using an HPGe detector. The variation in concentration of radionuclides for the area under investigation can be classified into regions of high, medium and low natural radioactivity. The average concentration in BqKg(-1) has been observed to be from 9.5 to 183675.7BqKg(-1) for (238)U, between 6.1 and 94,314.2BqKg(-1) for (232)Th and from 0 to 7894.6BqKg(-1) for (40)K. Radium equivalent activities (Ra(eq)), dose rate (D(R)) and external hazard (H(ex)) have also been determined. In the present work, the concentration of rare earth elements are measured for two feldspar samples using two techniques, Environmental Scanning Electron microscope XIL 30 ESEM, Philips, and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The existence of rare earth elements in this area are very high and can be used in different important industries. PMID:21324705

Walley El-Dine, Nadia; El-Shershaby, Amal; Afifi, Sofia; Sroor, Amany; Samir, Eman

2011-05-01

49

Extensional collapse along the Sevier Desert reflection, northern Sevier Desert basin, western United States  

NASA Astrophysics Data System (ADS)

Newly released and previously published seismic reflection data from the northern Sevier Desert basin provide a complete seismic transect between the tilted western margin of the basin and the eastern breakaway zone. When tied to well and surface age data, the transect delineates a continuum of extensional fault and basin fill geometries that developed between late Oligocene and Pleistocene time across the basin. A minimum of 18 km of top-to-the-west normal displacement is estimated across the Sevier Desert from only the most conspicuous growth geometries and offsets across listric normal faults that sole downward into the Sevier Desert reflection (SDR). The SDR clearly marks a normal fault zone beneath the entire basin, where stratal truncations are imaged for 50% of the 39 km length of the reflection east of the Cricket Mountains block. Restoration of extensional displacement along this entire 39 km fault length is necessary to reconstruct the pre-Oligocene configuration and erosion level of Sevier thrust sheets across the Sevier Desert area. The SDR normal fault zone underlies the former topographic crest of the Sevier orogenic belt, where it accommodated extensional collapse after cessation of regional contractile tectonism.

Coogan, James C.; Decelles, Peter G.

1996-10-01

50

Application of ground geophysical data to uranium mineralization in the El-Missikat area, central Eastern Desert, Egypt  

Microsoft Academic Search

The El-Missikat prospect lies in the Eastern Desert of Egypt, 85 km from Qena along the river Nile. The area of the prospect is covered by pink granites of the Gabal (G.) El-Missikat pluton from the south and quartz diorite from the north, as well as wadi alluvium at Wadi El-Missikat, which passes through the study area from south to

Elsayed M. Elkattan; Hassan M. Abdulhadi; Said I. Rabie; Hamdy I. E. Hassanein

1996-01-01

51

Structural elements and incremental strain history of the basement rocks of Um Had area, central Eastern Desert, Egypt  

Microsoft Academic Search

The Um Had area, central Eastern Desert, Egypt shows a regional stretching in the NW–SE and a contraction in the NE–SW direction.\\u000a Major NW–SE folds, small recumbent folds, and local thrusts and reverse faults were recognized. Complicated relation between\\u000a folds and boudinage was identified. This stretching amount ranges from 1.282 to 1.309. Earlier coaxial and later non-coaxial\\u000a strains were inferred.

Ahmed Akawy

2009-01-01

52

Age and tectonic setting of granitoid gneisses in the Eastern Desert of Egypt and south-west Sinai  

Microsoft Academic Search

Strongly deformed and locally migmatized gneisses occur at several places in the southern Eastern Desert of Egypt and in Sinai and have variously been interpreted as a basement to Pan-african (900 to 600 Ma) supracrustal and intrusive assemblages. A suite of grabbroic to granitic gneisses was investigated in the Hafafit area, which constitutes an I-type calc-alkaline intrusive assemblage whose chemistry

A. Krüner; J. Krüger; A. A. A. Rashwan

1994-01-01

53

Technologies Applied in the Toshka Project of Egypt  

ERIC Educational Resources Information Center

The Toshka Project, located in Egypt, involves excavating a canal to carry about 380 billion ft[supercript 3] of water every year from Lake Nasser to the Toshka Depression, southwest of Aswan. This will eventually create a new valley to the River Nile in the western desert of Egypt in addition to the currently existing prehistoric river course.…

Wahby, Wafeek S.

2004-01-01

54

Petrogenesis of selected A-type granitic intrusions from Central Eastern Desert of Egypt  

NASA Astrophysics Data System (ADS)

The Pan-African orogeny in the Arabian-Nubian Shield was terminated by intrusion of A-type granites (~ 595 Ma; Greenberg, 1981) and its volcanic equivalents. Subsequent to the intrusions of these granitic bodies the shield was exhumed. Eroded A-type granite pebbles were found in the molasse sediments that were deposited in intermountain basins. Therefore the A-type granites provide information about the last stage of the Pan-African geochemical system. Preliminary whole-rock geochemical data of three granitic intrusions (Kadabora, Um Naggat and El shiekh Salem) from the Central Eastern Desert of Egypt; indicate that all of them are peraluminous and with A-type characteristics. These intrusions show low CaO content (average 0.43 %wt), high FeOT/MgO ratio (10.46-121.88), high Na2O+K2O (average 8.04 %wt), marked enrichment of high field strength elements (Y, Nb and Ga except Zr), depletion in MgO (0.01-0.11 %wt) and with low concentration of Sr and Ba. The studied granitoids were emplaced in within plate tectonic regime. References: Greenberg, J.K. (1981): Characteristic and origin of Egyptian younger granites. Bull. Geol. Soc. Am. Part 1, v.92: 224-232.

Hassan, Tharwat; Asran, Asran; Amron, Taha; Hauzenberger, Christoph

2014-05-01

55

Remote sensing and geochemical investigations of selected surface processes in Egypt and Missouri  

Microsoft Academic Search

This thesis consists of three studies of surface processes on Earth: 1. Age and isotopic constraints of pluvial episodes in the Western Desert of Egypt. North Africa has undergone drastic climatic change over the past several hundred thousand years. Timing of humid intervals called pluvials was investigated by uranium- series disequilibrium dating of travertines from the Kurkur Oasis, Western Desert,

Mary Katherine Crombie

1997-01-01

56

Chemical and isotopic constraints on the origin of Wadi El-Tarfa ground waters, Eastern Desert, Egypt.  

SciTech Connect

We evaluated the use of the renewable ground water resources of the Eastern Desert to develop sustainable agriculture in Upper Egypt, an alternative that could alleviate some of Egypt's dependence on water from the Nile River. Ground water from shallow aquifers in the Eastern Desert of Egypt, near the intersection of Wadi El-Tarfa and the Nile River, was analyzed for chemical compositions, stable isotope ratios, and tritium activities. The ground water has a range in total dissolved solids of 300 to 5000 mg/L. Values of {delta}D and {delta}{sup 18}O range from -10 to +34 %o and -2 to +5.2 %o, respectively, and defines a line having a slope of 5.7 that intersects the meteoric water line at about {delta}D = -15% on a plot of 8D versus {delta}{sup 18}O. These findings indicate that the water might have been derived by a combination of evaporation of and salt addition to regional precipitation. Only one sample could have been derived directly by evaporation and transpiration of modern Nile River water. Salinization of the ground water could have occurred through dissolution of marine aerosol dry fallout, carbonate minerals, gypsum, and other trace evaporitic minerals at and near the ground surface. Tritium activities ranged from 0.04 to 12.9 TU (tritium unite), indicating that all but one of the samples were derived at least partly from precipitation that occurred within the last 45 years. These data indicate that Nubian Aquifer paleowater is not a significant component of the shallow aquifers of this portion of the Eastern Desert. The most likely source of this ground water is sporadic flash flood events yielding locally voluminous recharge that accumulates in coarse sediments and fractured rock beneath alluvial channels. The magnitude of this renewable ground water resource and its potential for supporting sustainable agriculture require further investigation.

Sultan, M.; Sturchio, N. C.; Abdel Hady, Y.; El Anbeawy, M.; Environmental Research; Cairo Univ.

2000-10-01

57

The role of the Najd Fault System in the tectonic evolution of the Hammamat molasse sediments, Eastern Desert, Egypt  

Microsoft Academic Search

The Hammamat molasse sediments of the Eastern Desert of Egypt were deposited in isolated basins formed during an initial stage\\u000a of orogen parallel N–S extension (650–580 Ma) in the Neoproterozoic time. Supply of sediments to the molasse basins began\\u000a after the eruption of Dokhan volcanics (602–593 Ma), exhumation of core complexes (650–550 Ma), and intrusion of late tectonic\\u000a granites (610–550 Ma). The late Neoproterozoic

Mohamed A. Abd El-Wahed

2010-01-01

58

Geochemistry and Petrogenesis of the Late Jurassic-Early Cretaceous Mansouri Ring Complex, Southeastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The Mansouri Ring Complex is an eccentric mass (9 × 6 km) located in the extreme southwestern part of the Eastern Desert of Egypt. The complex exhibits a poorly defined ring structure and a limited variety of rock types: trachytes, alkali feldspar syenites and rhyolitic dykes. The rocks are hypersolvus, porphyritic and less commonly show trachytic textures. The complex has a high fracture density consisting of two dominant fault systems trending west-northwest and east-west. The rocks are silica-oversaturated; trachytes and syenites are mildly metaluminous to peralkaline, while rhyolites are mainly peraluminous due to the relative loss of a peralkaline fluid phase. The rocks are enriched in high field strength elements (Nb, Zr, Y) reflecting a within-plate tectonic setting. The curvilinear trends defined by some major and trace element variations, together with the decrease in the K/Rb ratio and concomitant increase in Rb/Ba and Rb/Sr ratios, indicate the important role of feldspar fractionation during the evolution of the Mansouri Complex. In some Mansouri rocks, radioactive anomalies are mainly associated with shear zones aligned along the east-west direction and characterised by abnormal accumulations of U- and Th-bearing accessory minerals like monazite, allanite, apatite and titanite. The Mansouri Ring has carbonatite rocks of calcitic, calcitic-dolomitic and dolomitic varieties; the latter is widely abundant. Apatite, monazite, pyrochlore, sphalerite, pyrrohotite and magnetite are the common accessory minerals associated with the Mansouri carbonatites. The U and Th contents of the carbonatites range from 10-25 ppm and 40-250 ppm, respectively. The U and Th contents of the alkali feldspar syenites range from 1-9 ppm and 3-10 ppm, respectively. The low Y/Nb ratios (< 0.6), together with the relatively low initial 87Sr/ 86Sr ratio (0.705) of the Mansouri rocks, substantiates the dominant role of mantle-derived magma in their genesis.

El-nisr, S. A.; Saleh, G. M.

2001-01-01

59

Desert  

NSDL National Science Digital Library

Become an expert on the Desert habitat!! Begin your search for information by reading below. You can click on the underlined words to take you to the website you want to go to. Have fun! Read carefully. Visit the Desert to learn all about the desert! All about the desert also has lots of important facts about deserts. This site includes animals in the desert. Desert Facts is a great place to find lots of different facts about the desert! Kenley, you can click on "desert animals" to find a list of animals ...

Ryan, Ms.

2013-02-12

60

Activity area, movement patterns, and habitat use of the desert monitor, varanus griseus, in the zaranik protected area, north Sinai, Egypt  

Microsoft Academic Search

A radio telemetry study of the desert monitor, Varanus griseus was conducted from July 1997 to June 1998 in the Zaranik Protected Area, North Sinai, Egypt. Five monitor lizards (SVL range 302 ? 360 mm) were equipped with SI?2T temperature sensitive transmitters. Two individuals (male # 1 and female # 2) were residents of Fluseyyat Island in Zaranik, and three

Adel A. Ibrahim

2002-01-01

61

Petrology and geochemistry of the banded iron formation (BIF) of Wadi Karim and Um Anab, Eastern Desert, Egypt: Implications for the origin of Neoproterozoic BIF  

Microsoft Academic Search

Banded iron formation (BIF) is exposed among the Precambrian rocks in the Wadi Karim and Um Anab areas in the Eastern Desert of Egypt. The BIF conformably alternates with Neoproterozoic arc metavolcanic rocks, which comprise metabasalts and mafic to intermediate metapyroclastic rocks. The BIF of Wadi Karim belongs to the oxide and mixed carbonate-oxide facies, while that of Um Anab

Fawzy F. Basta; Ayman E. Maurice; Lluís Fontboté; Pierre-Yves Favarger

2011-01-01

62

Neoproterozoic ophiolitic peridotites along the Allaqi-Heiani suture, South Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The Wadi Allaqi ophiolite along the Egyptian-Sudanese border defines the southernmost ophiolitic assemblage and suture zone in the Eastern Desert. Ophiolite assemblages comprise nappes composed mainly of mafic and ultramafic rocks that were tectonically emplaced and replaced by serpentine and carbonates along shear zones probably due to CO2-metasomatism. Serpentinites, altered slices of the upper mantle, represent a distinctive lithology of dismembered ophiolites of the western YOSHGAH suture. Microscopically, they are composed of more than 90 % serpentine minerals with minor opaque minerals, carbonate, brucite and talc. The mineral chemistry and whole-rock chemical data reported here indicate that the serpentinized peridotites formed as highly-depleted mantle residues. They show compositions consistent with formation in a suprasubduction zone environment. They are depleted in Al2O3 and CaO similar to those in fore-arc peridotites. Also, high Cr# (Cr/ (Cr+Al)) in the relict chrome spinels (average ~0.72) indicates that these are residual after extensive partial melting, similar to spinels in modern fore-arc peridotites. Therefore, the studied serpentinites represent fragments of an oceanic lithosphere that formed in a fore-arc environment, which belongs to an ophiolitic mantle sequence formed in a suprasubduction zone.

Azer, M. K.; Samuel, M. D.; Ali, K. A.; Gahlan, H. A.; Stern, R. J.; Ren, M.; Moussa, H. E.

2013-10-01

63

Deserts  

NSDL National Science Digital Library

Deserts, one of the four major terrestial biomes, cover about one-fifth of Earth's land area. This interactive slide presentation shows some aspects of deserts, including dunes, desert-adapted plants, oases, and sculpted rock formations. There is also a map showing the distribution of the world's deserts. A background essay and discussion questions are included.

64

Determination of chromium and trace elements in El-Rubshi chromite from Eastern Desert, Egypt by neutron activation analysis.  

PubMed

Neutron activation analysis (NAA) is one of the most powerful analytical techniques for multielement determination of rocks. In the present work NAA and HPGe detector gamma-spectroscopy was used to determine chromium and 15 minor and trace elements qualitatively and quantitatively from chromite rock samples collected from El-Robshi area in the Eastern Desert, Egypt. The samples were properly prepared together with their standards and simultaneously irradiated by thermal neutrons at the TRIGA Mainz research reactor. Short time irradiation (1-5min) was used to determine Mg, Ti and Mn. Long time irradiation (6h) was used to determine Na, Ga, As, La, Sc, Cr, Fe, Co, Zn, Zr, Ce, Ce, Yb, Lu, Hf and Ta. In El-Robshi chromite comprises 18 sites, more than 100 lenses of massive chromite, more than 2700 tons averaging 44% Cr(2)O(3) and the average of (51)Cr 40.2%. PMID:20444611

El-Taher, A

2010-09-01

65

Diagenesis of the lower Eocene Thebes Formation, Gebel Rewagen area, Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The diagenesis of lower Eocene shallow water carbonates with flint was studied in the Gebel Rewagen area, Eastern Desert, Egypt. The carbonates are mainly wackestones to packstones with benthic bioclasts embedded in a dark red luminescent micrite matrix. The studied succession displays a complex diagenetic history that involves syngenetic and late diagenetic processes. Silica, which exists either as persistent bands, nodules and/or silicified benthic bioclasts shows a distinctive pattern regarding its distribution, source, depositional environments and timing. Three lines of evidence support a syngenetic origin of the chert bands: (1) they alternate in a cyclic manner within the host carbonates and (2) they exhibit noticeable lateral persistence throughout the investigated area following the strata boundaries and (3) there is a lack of any carbonate dissolution in limestone adjacent to chert bands. The deposition of silica bands in association with shallow water carbonates is possibly related to eustatic sea-level changes, which were accompanied by episodic variations in silica and carbonate productivities. With a relative sea-level fall and the establishment of a lowstand period at the end of the early Eocene, a basinward shift of the groundwater zones is expected within the carbonate platform. During this period some late diagenetic processes took place, which involve: (1) the formation of siliceous and carbonate concretionary growths, (2) partial silicification of bioclasts, (3) neomorphic stabilization of the CaCO 3 bioclasts and (4) the formation of equant calcite cement. Siliceous and carbonate concretions are believed to have taken place within microenvironments created and controlled by sulphate-reducing bacteria and physico-chemical and kinetic factors near a marine-meteoric water mixing zone. This is inferred from the distribution of iron sulphides, the non-ferroan nature of all concretions and the depleted ?13C (-5.4‰ to -6.0‰ PDB) and ?18O (-5.8‰ to -6.8‰ PDB) values of the carbonate concretions. The silica fabrics of all the partly silicified benthic bioclasts, with abundant pyrite cubes, argue for a delayed silicification process within the sulphate reduction zone. The close and relatively depleted ?18O values of the low-Mg calcite micrite matrix (-3.0‰ to -4.4‰ PDB) and benthic bioclasts (-3.4‰ to -4.8‰ PDB) indicate that both matrix and bioclasts have probably suffered neomorphic stabilization from freshwater-dominated solutions. The initial marine ?13C values of both low-Mg calcite matrix (+0.2‰ to -2.2‰ PDB) and altered benthic bioclasts (-0.2‰ to -0.9‰ PDB) are retained and not affected by diagenesis. The luminescence character and the extremely depleted oxygen values (-8.3‰ to -10.1‰ PDB) of the equant void-filling calcite mosaics are consistent with their formation within a meteoric phreatic realm.

Shaaban, Mohamad N.

2004-03-01

66

Origin of Neoproterozoic ophiolitic peridotites in south Eastern Desert, Egypt, constrained from primary mantle mineral chemistry  

NASA Astrophysics Data System (ADS)

The ophiolitic peridotites in the Wadi Arais area, south Eastern Desert of Egypt, represent a part of Neoproterozoic ophiolites of the Arabian-Nubian Shield (ANS). We found relics of fresh dunites enveloped by serpentinites that show abundances of bastite after orthopyroxene, reflecting harzburgite protoliths. The bulk-rock chemistry confirmed the harzburgites as the main protoliths. The primary mantle minerals such as orthopyroxene, olivine and chromian spinel in Arais serpentinites are still preserved. The orthopyroxene has high Mg# [=Mg/(Mg + Fe2+)], ~0.923 on average. It shows intra-grain chemical homogeneity and contains, on average, 2.28 wt.% A12O3, 0.88 wt.% Cr2O3 and 0.53 wt.% CaO, similar to primary orthopyroxenes in modern forearc peridotites. The olivine in harzburgites has lower Fo (93-94.5) than that in dunites (Fo94.3-Fo95.9). The Arais olivine is similar in NiO (0.47 wt.% on average) and MnO (0.08 wt.% on average) contents to the mantle olivine in primary peridotites. This olivine is high in Fo content, similar to Mg-rich olivines in ANS ophiolitic harzburgites, because of its residual origin. The chromian spinel, found in harzburgites, shows wide ranges of Cr#s [=Cr/(Cr + Al)], 0.46-0.81 and Mg#s, 0.34-0.67. The chromian spinel in dunites shows an intra-grain chemical homogeneity with high Cr#s (0.82-0.86). The chromian spinels in Arais peridotites are low in TiO2, 0.05 wt.% and YFe [= Fe3+/(Cr + Al + Fe3+)], ~0.06 on average. They are similar in chemistry to spinels in forearc peridotites. Their compositions associated with olivine’s Fo suggest that the harzburgites are refractory residues after high-degree partial melting (mainly ~25-30 % partial melting) and dunites are more depleted, similar to highly refractory peridotites recovered from forearcs. This is in accordance with the partial melting (>20 % melt) obtained by the whole-rock Al2O3 composition. The Arais peridotites have been possibly formed in a sub-arc setting (mantle wedge), where high degrees of partial melting were available during subduction and closing of the Mozambique Ocean, and emplaced in a forearc basin. Their equilibrium temperature based on olivine-spinel thermometry ranges from 650 to 780 °C, and their oxygen fugacity is high (?log ƒO2 = 2.3 to 2.8), which is characteristic of mantle-wedge peridotites. The Arais peridotites are affected by secondary processes forming microinclusions inside the dunitic olivine, abundances of carbonates and talc flakes in serpentinites. These microinclusions have been formed by reaction between trapped fluids and host olivine in a closed system. Lizardite and chrysotile, based on Raman analyses, are the main serpentine minerals with lesser antigorite, indicating that serpentines were possibly formed under retrograde metamorphism during exhumation and near the surface at low T (<400 °C).

Khedr, Mohamed Zaki; Arai, Shoji

2013-10-01

67

Revegetation Techniques and Fugitive Dust in the Western Mojave Desert.  

National Technical Information Service (NTIS)

In the Antelope Valley of the Mojave Desert, tillage and seeding of native shrubs reduced emissions of fugitive dust from disturbed lands by more than 95%, achieving ground cover comparable to surrounding old field successional areas. Wind fences, furrowi...

D. Grantz D. L. Vaughn

1998-01-01

68

Some biomedical applications of Balanites aegyptiaca grown naturally in radioactive area, Southeastern Desert, Egypt  

Microsoft Academic Search

Balanites aegyptiaca is a naturally grown desert plant at some radioactive places in Wadi El-Gemal area, Southeastern Desert. The aim of the present study was to highlight on the B. aegyptiaca species grown naturally at radioactive places in Wadi El-Gemal area (fruit part) on the ability of using the fruit in some biomedical application (glucose, cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and

A. M. A. Morsy; I. A. Ahmad; A. M. Kamel

2010-01-01

69

Petrology and petrogenesis of the older and younger granitoids of Wadi Beizah area, Central Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The studied granitoids of Wadi Beizah area, Central Eastern Desert, Egypt, are represented by older arc-granitoids intruded by a post-collisional stock of younger pink granite. The arc-granitoids (I-type) cover a wide compositional spectrum from meladiorites, diorites, quartzdiorites/monzodiorites and tonalites, to leucogranodiorites. Their distribution pattern is unimodal dominated by diorites. They are of low-K calc-alkaline character and represent the plutonic rocks of the mature, ensimatic island arc stage. Three models for the geotectonic environment of the younger granites of the Eastern Desert of Egypt have been suggested: (1) Within-plate, rifting, tensional environment similar to the Oslo Rift of Norway (Greenberg, 1981) Stern et al., 1984, 1986), (2) Extensive crustal anatexis during collisional tectonics, compression, thickening of the crust and thrust imbrication (Hussein et al., 1982; Ragab, 1987b), (3) Active continental margin geotectonic environment (Abdel-Rahman and Martin, 1987). These three models are discussed in detail. The present workers believe that the Younger Granites in general are the products of extensive crustal anatexis at the culmination of the Pan-African orogenic cycle when arc-arc suturing is complete. Recent studies revealed a low-angle thrust event in the Central Eastern Desert followed the initial arc-arc collision and continued after the deposition of the molasse-type sediments (Ries et al., 1983; El-Ramly et al., 1984; Greiling et al., 1984; Habib et al., 1985; Greiling and El-Ramly, 1985) which indicate thickening of the crust and compression regime at the time of emplacement of the Younger Granites. The dominance of ?granite minimum? composition of these late orogenic granites suggests extensive crustal anatexis. Their low Nb-content (< 40 ppm) precludes within-plate hot-spot related magma, in comparison with: (1) The post-Pan-African (400-100 M.a.) granitic rocks from the NE Sudan which on a geochemical evidence are the products of within-continental plate ?hot-spot? magmatism with Nb-content of about 50-300 ppm (Gass, 1979); (2) The Oslo Rift within-plate granites with Nb-content of 226 ppm (Pearce et al., 1984). A post-collision model showing the formation of the ?petrotectonic assemblage? of this stage (molasse-type sediments deposited in fault-bounded troughs, and calc-alkaline bimodal intermediate and felsic magmas) as well as the heat sources in the geotectonic environment of thrust imbrication and the mode of formation of the Younger Granites by crustal anatexis is suggested. K/Ar dating of a younger granite sample gave an age of 584 ± 5 M.a. which is compatible with several similar ages of younger pink granites in the Eastern Desert of Egypt. An older granite sample gave an age of 591 ± 7 M.a. (K/Ar method) indicating resetting of its isotopic clocks probably as a result of the extensive crustal anatexis event.

Ragab, A. I.; Menesy, M. Y.; Diab, M. M.

70

Effect of ploughing on plant species abundance and diversity in the northwestern coastal desert of Egypt  

Microsoft Academic Search

This study focuses on the effect of ploughing on plant abundance,vegetation cover, species richness, and taxonomic diversity during the growingseasons (winter and spring) of 1992 and 2000 in the habitat of inland plateau(natural habitat), 21 km south of Mersa-Matrouh (Egypt).Ninety-five species belonging to 27 families were recorded. High percentages oflife-forms and a large number of species were recorded in ploughed

Sania K. Hammouda; Selim Z. Heneidy

2003-01-01

71

Sulfuric acid leaching of Kab Amiri niobium–tantalum bearing minerals, Central Eastern Desert, Egypt  

Microsoft Academic Search

The ore under study was obtained from the Kab Amiri area located close to the northern boundary of the Central Eastern Desert. The ore is constituted of different kinds of refractory minerals. These are mainly represented by the niobium–tantalum rare earth-bearing minerals namely euxinite, samarsakite and fergusonite, beside the uranium refractory minerals davidite and zircon. Increasing demand for niobium, tantalum,

Omneya M El-Hussaini; Mohamed A Mahdy

2002-01-01

72

Petrogenetic and geotectonic significance of Neoproterozoic suprasubduction mantle as revealed by the Wizer ophiolite complex, Central Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

Ophiolite complexes, formed in a suprasubduction zone environment during Neoproterozoic time, are widely distributed in the Eastern Desert of Egypt. Their mantle sections provide important information on the origin and tectonic history of ocean basins these complexes represent. The geochemistry and mineralogy of the mantle section of the Wizer ophiolite complex, represented by serpentinites after harzburgite containing minor dunite bodies, are presented. Presence of antigorite together with the incipient alteration of chromite and absence of chlorite suggests that serpentinization occurred in the mantle wedge above a Neoproterozoic subduction zone. Wizer peridotites have a wide range of spinel compositions. Spinel Cr# [100Cr/(Cr + Al)] decrease gradually from dunite bodies (Cr# = 81-87) and their host highly depleted harzburgites (Cr# = 67-79) to the less depleted harzburgites (Cr# = 57-63). Such decreases in mantle refractory character are accompanied by higher Al and Ti contents in bulk compositions. Estimated parental melt compositions point to an equilibration with melts of boninitic composition for the dunite bodies (TiO2 = ~<0.07-0.22 wt%; Al2O3 = 9.4-10.6 wt%), boninitic-arc tholeiite for the highly depleted harzburgites (TiO2 = <0.09-0.28 wt%; Al2O3 = 11.2-14.1 wt%) and more MORB-like affinities for the less depleted harzburgites (TiO2 = ~<0.38-0.51 wt%; Al2O3 = 14.5-15.3 wt%). Estimated equilibrium melts are found in the overlying volcanic sequence, which shows a transitional MORB-island arc geochemical signature with a few boninitic samples. Enrichment of some chromites in TiO2 and identification of sulfides in highly depleted peridotites imply interaction with an impregnating melt. A two-stage partial melting/melt-rock reaction model is advocated, whereby, melting of a depleted mantle source by reaction with MORB-like melts is followed by a second stage melting by interaction with melts of IAT-boninitic affinities in a suprasubduction zone environment to generate the highly depleted harzburgites and dunite bodies. The shift from MORB to island arc/boninitic affinities within the mantle lithosphere of the Wizer ophiolite sequence suggests generation in a protoarc-forearc environment. This, together with the systematic latitudinal change in composition of ophiolitic lavas in the Central Eastern Desert (CED) of Egypt from IAT-boninitic affinities to more MORB-like signature, implies that the CED could represent a disrupted forearc-arc-backarc system above a southeast-dipping subduction zone.

Farahat, E. S.; Hoinkes, G.; Mogessie, A.

2011-10-01

73

Petrology and Geochemistry of ultramafic rocks from Wadi Alam, South Eastern Desert of Egypt: evidences for two Neoproterozoic mantle reservoirs?  

NASA Astrophysics Data System (ADS)

Ultramafic rocks of the Neoproterozoic age are common in the Eastern Desert of Egypt. These rocks are commonly considered as a part of the widely distributed dismembered ophiolite sequence. The studied ultramafic rocks from Wadi Alam are classified into two main domains: mantle slices and non-slice ultramafics with intrusive nature. The non-slice ultramafics are observed within the mantle slices. Petrological and geochemical studies of the Neoproterozoic ultramafic rocks from wadi Alam in the South Eastern Desert of Egypt provided new evidences for possibility of two Neoproterozoic mantle reservoirs. The serpentinized ultramafic mantle slices have harzburgite composition. They underwent melting with 23.4 to 24% melt extraction. Following the melting, rocks suffered cryptic mantle metasomatism, including chemical enrichment of the incompatible elements (LILEs, HFSEs and LREE) relative to the primitive mantle compositions. Metasomatism in the mantle reservoir of the studied rocks took place mostly by hydrous fluids or silicate melts, which were derived from subducting oceanic lithosphere. The non-slice ultramafics are classified as cumulates and their compositions range from the dunite, lherzolite to harzburgite. They initially were formed from MORB or Mg-rich tholeiitic melts. Their clinopyroxenes record formation temperature of 700 to 1192 ° C and pressure of 10 to 12 kbar (i.e. 30-40 km depth). The enrichment characteristics of these rocks in the incompatible elements may reflect a metasomatized mantle source. The metasomatic signs of the proposed mantle source are related to melts derived from a subducting oceanic slab. Based on the Cr# and Mg# of the unaltered spinel cores, the serpentinized mantle slices formed in oceanic mantle wedge in the fore-arc setting. On the other hand, formation of the non-slice ultramafics (melts-derived rocks) occurred in a nascent fore-arc setting, subsequent to the formation of the mantle slice peridotites. It is assumed that the mantle slice peridotites were the source for the parental melts of the non-slice ultramafics, where the melting occurred due to spreading in the MOR-arc transition setting. Also, the difference in the degree of serpentinization for the mantle slices with signs of higher degrees of metamorphism in one hand and the non-slice ultramafic bodies refers to different serpentinization events among these rocks.

Gamal El Dien, Hamed; Hamdy, Mohamed; Salam Abu El-Ela, Abdel; Hassan, Adel

2014-05-01

74

Extending the western North American Proterozoic and Paleozoic continental crust through the Mojave Desert  

SciTech Connect

Data supporting the existence of Proterozoic basement in the central and western Mojave Desert include U-Pb zircon geochronology and Nd, Sr, and Pb isotopic values of quartzofeldspathic gneisses, detrital zircon provenance ages, and the presence of basement clasts in Paleozoic and Mesozoic conglomerates. These data corroborate existing isotopic data from Mesozoic and Tertiary intrusive rocks that suggest involvement of Proterozoic crust in their genesis. Exposures of Proterozoic basement and Late Proterozoic and Paleozoic transitional miogeoclinal-cratonal facies trends in the central and western Mojave Desert consistently imply that cratonal North America continues westward uninterrupted through this region to the San Andreas fault. These data place geographic limits on the position of several pre-Tertiary tectonic elements speculated to exist in the Mojave Desert.

Martin, M.W.; Walker, J.D. (Univ. of Kansas, Lawrence (United States))

1992-08-01

75

Ground-water quality and geochemistry, Carson Desert, western Nevada  

USGS Publications Warehouse

Aquifers in the Carson Desert are the primary source of drinking water, which is highly variable in chemical composition. In the shallow basin-fill aquifers, water chemistyr varies from a dilute calcium bicarbonate-dominated water beneath the irrigated areas to a saline sodium chloride- dominated water beneath unirrigated areas. Water samples from the shallow aquifers commonly have dissolved solids, chloride, magnesium, sulfate, arsenic, and manganese concentrations that exceed State of Nevada drinking-water standards. Water in the intermediante basin-fill aquifers is a dilute sodium bicarbonate type in the Fallon area and a distinctly more saline sodium chloride type in the Soda Lake-Upsal Hogback area. Dissolved solids, chloride, arsenic, fluoride, and manganese concen- trations commonly exceed drinking-water standards. The basalt aquifer contains a dilute sodium bicarbonate chloride water. Arsenic concentrations exceed standards in all sampled wells. The concen- trations of major constituents in ground water beneath the southern Carson Desert are the result of evapotranspiration and natural geochemical reactions with minerals derived mostly from igneous rocks. Water with higher concentrations of iron and manganese is near thermodynamic equilibrium with siderite and rhodochrosite and indicates that these elements may be limited by the solubility of their respective carbonate minerals. Naturally occurring radionuclides (uranium and radon-222) are present in ground water from the Carson Desert in concen- tratons higher than proposed drinking-water standards. High uranium concentrations in the shallow aquifers may be caused by evaporative concentration and the release of uranium during dissolution of iron and manganese oxides or the oxidation of sedimentary organic matter that typically has elevated uranium concentrations. Ground water in the Carson Desert does not appear to have be contaminated by synthetic organic chemicals.

Lico, Michael S.; Seiler, R. L.

1994-01-01

76

Geothermal resources of the western Black Rock Desert, northwestern Nevada: hydrology and aqueous geochemistry  

Microsoft Academic Search

The western Black Rock Desert includes several systems, some of which exceed 150 and may reach 200 degrees Celsius at depth based on chemical geothermometry. Geochemical and isotopic data, used in conjunction with hydrologic and geophysical information, indicate that several hydrologically distinct systems are present and are all recharged by local meteoric water. The thermal water at Great Boiling and

1985-01-01

77

Desert landforms of southwest Egypt: A basis for comparison with Mars  

NASA Technical Reports Server (NTRS)

Geologic interpretations of The Gilf Kebir-Uweinat of Apollo-Soyuz photographs were verified. The photographs and LANDSAT images showed features reminiscent of those depicted by Mariner and Viking missions to Mars. These features were to better understand their morphologic analogs on Mars. It is indicated that climate change played a significant role in the formation of the eastern Sahara. It is also revealed that correlations between the eolian features in southwestern Egypt and the wind blown patterns on the surface of Mars result in a better understanding of eolian activity on both planets.

El-Baz, F. (editor); Maxwell, T. A. (editor)

1982-01-01

78

Some biomedical applications of Balanites aegyptiaca grown naturally in radioactive area, Southeastern Desert, Egypt.  

PubMed

Balanites aegyptiaca is a naturally grown desert plant at some radioactive places in Wadi El-Gemal area, Southeastern Desert. The aim of the present study was to highlight on the B. aegyptiaca species grown naturally at radioactive places in Wadi El-Gemal area (fruit part) on the ability of using the fruit in some biomedical application (glucose, cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and diabetes). The investigated plant was collected from different location at Wadi El-Gemal area. The uranium content was determined previously and different concentrations from the fruit with highest uranium content were used to examine the effect of B. aegyptiaca (fruit part) on the glucose, triglycerides, total cholesterol (HDL and LDL-cholesterol) levels using experimental rats. Different analysis techniques were used in order to determine different parameters. The obtained data suggest the beneficial role of B. aegyptiaca fruit as an anti-diabetic and hypo-lipidimic agent. PMID:20226589

Morsy, A M A; Ahmad, I A; Kamel, A M

2010-06-15

79

El-Dab'a ground water aquifer assessment, Egypt  

NSDL National Science Digital Library

El-Dabaa area is an area located in the norther part of the western desert, Egypt and planed to be nuclear power point. Some vertical electrical sounding have been done there to evaluate the ground water aquifer there to monitor the effect of sea water intrusion and its effect on the fresh water aquifer

Tarabees, Elhamy

80

Natural radioactivity levels and radiation hazard indices in granite from Aswan to Wadi El-Allaqi southeastern desert, Egypt.  

PubMed

Studies on radiation level and radionuclide distribution in granite from Aswan to Wadi El-Allaqi area that is located in southeastern desert of Egypt were undertaken. The samples collected from five locations: Gabal El Mesala, Umm Hibal, Abu Herigle, Abu Marw and Deneibit El Quleib. The purpose of this study is to provide a baseline map of radioactivity background levels in the investigated area environment, and this study will be used as reference information to assess any changes in the radioactive background level due to geological processes. The highest average values of 226Ra and 232Th concentrations (24.00 and 31.28 Bq kg(-1), respectively) were observed at Abu Herigle region, whereas the highest average value of 40K concentration, 589.95 Bq kg(-1), was detected in Umm Hibal. The absorbed dose rate in air was found to be in the range between 5.40 and 45.11 nGy h(-1), and radium equivalent activity concentration was found in the range between 29.57 and 71.85 Bq kg(-1). Also the representative external hazard index values for the corresponding samples were also estimated and given. PMID:17569689

El-Taher, A; Uosif, M A M; Orabi, A A

2007-01-01

81

Banded iron formations of Um Nar, Eastern Desert of Egypt: P–T–X conditions of metamorphism and tectonic implications  

NASA Astrophysics Data System (ADS)

Banded iron formations (BIF) in Um Nar, central eastern desert of Egypt, occur intercalated with schists of volcaniclastic and epiclastic origins within "ophiolitic–island arc rocks" of the Arabo–Nubian Shield. The BIF and its host rocks were affected by folding, thrusting, and regional metamorphism during the Pan-African Orogeny resulting in the development of north-verging overturned folds and E–W striking, S-dipping thrusts. Following the intrusion of granitoids, the entire sequence was refolded into south-plunging folds with NW–SE trending fold axes. Peak mineral assemblages of hornblende + plagioclase, and garnet + biotite + plagioclase + quartz in the host rocks, and andradite-rich garnet + epidote + hematite + magnetite + quartz in the BIF indicate metamorphism under epidote amphibolite facies conditions. Using the multiequilibrium approach of Thermocalc, and conventional thermobarometry, peak P–T conditions of metamorphism are estimated at 520 ± 30 °C, 5 ± 2 kbar. Fluids attending peak conditions in the oxide facies layers of the BIF were characterized by XCO2 ~ 0.03 and log fO2 ~ ? 40. Textural and mineral chemical criteria suggest that, following peak conditions, the rocks underwent a stage of near-isobaric cooling or cooling and compression characteristic of a counter-clockwise P–T path.

El-Shazly, A. K.; Khalil, K. I.

2014-05-01

82

Rare earth elements content in geological samples from eastern desert, Egypt, determined by instrumental neutron activation analysis.  

PubMed

Twenty representative geological samples (tonalite, granodiorite, adamellite, syenogranite, rapakivi syenogranite, alkali feldspar granite and monzogranite) were collected from G. Kattar area in Eastern Desert, Egypt, for analysis by instrumental neutron activation as a sensitive nondestructive analytical tool for the determination of 14 rare earth elements (REEs) and to find out the following: (1) what information could be obtained about the REEs and distribution patterns of REEs in geological samples under investigation, (2) to estimate the accuracy, reproducibility and detection limit of the INAA method in case of the given samples. The samples were properly prepared together with standard reference material and simultaneously irradiated in a neutron flux of 7x10(11)n/cm(2)s in the TRIGA Mainz research reactor facilities. The gamma spectra were collected by an HPGe detector and the analysis was done by means of a computerized multichannel analyzer. The choice of the nuclear reaction, irradiation and decay times, and of the proper gamma radiation in counting are presented and discussed. The results are found to be in good agreement with certified values. PMID:20236830

El-Taher, A

2010-09-01

83

Groundwater quality and management in arid and semi-arid regions: Case study, Central Eastern Desert of Egypt  

NASA Astrophysics Data System (ADS)

This study presents a model budget for groundwater in the Central Eastern Desert of Egypt. The stable isotopic composition and hydrochemistry of groundwater samples collected from different aquifers were determined to identify recharge sources and water quality. Stable isotopic values suggest that shallow alluvial and fracture zone aquifers are recharged from seasonal precipitation, while groundwater in deeper sedimentary sub-basins is paleowater that was recharged during periods of less arid regional climate. Hydrochemical analysis indicates elevated salinity in each aquifer type, which is attributed to leaching and dissolution of terrestrial salts and to mixing with marine water. Groundwater from sedimentary sub-basin aquifers can be treated and used for drinking and domestic purposes. Groundwater from shallow alluvial and fracture zone wells is suitable for animal husbandry and mineral ore dressing. A model water budget shows that approximately 4.8 × 109 m3 of recoverable groundwater is stored in sedimentary sub-basin aquifers, or approximately 550 years of water at present utilization rates.

Amer, Reda; Ripperdan, Robert; Wang, Tao; Encarnación, John

2012-07-01

84

Seismic hazard studies in Egypt  

NASA Astrophysics Data System (ADS)

The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba-Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5°) within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA) values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA) values were detected in the western part of the western desert and it is less than 25 gal.

Mohamed, Abuo El-Ela A.; El-Hadidy, M.; Deif, A.; Abou Elenean, K.

2012-12-01

85

Construction of a hydrologic model for estimating Wadi runoff and ground water recharge in the Eastern Desert, Egypt.  

SciTech Connect

We constructed a hydrologic model to estimate the groundwater recharge rate for alluvial aquifers of the Eastern Desert from sporadic precipitation over the Red Sea hills. To estimate initial losses over sub-basins, transmission losses through channel routing, and downstream runoff, we developed an integrated model combining spatial rainfall distribution, an appropriate basin unit hydrograph, and appropriate infiltration parameters. Watersheds and stream networks identified from digital terrain elevation data were verified by comparison with co-registered Landsat thematic mapper scenes and geologic maps. Records of a November 1994 storm event acquired from rain gauges along the Nile River and the Red Sea shore were used to generate a spatial precipitation distribution for the study area. A 2 hour design hyetograph was adopted from rain gauge data for the 1994 flood event. The model was tested against records from the November 1994 flood event at the outlets of the Tarfa and Hammamat watersheds. Groundwater recharge rates were estimated for the alluvial aquifers within the major watersheds of the north Eastern Desert. We estimated that during the 1994 flood event, the ground water recharge through transmission losses ranged from 21 to 31% (Tarfa: 15.8 x 10{sup 6} m{sup 3}; Asyuti: 20 x 10{sup 6} m{sup 3}, Qena: 49 x 10{sup 6} m{sup 3}, Hammamat: 59 x10{sup 6} m{sup 3}) of the precipitated volume. The initial losses ranged from 65 to 77%. Only 3-7% of the precipitation reached the watershed outlets. Archival data show that rainfall events of the size of the November 1994 storm or larger occur every 40 months; thus, the annual recharge rates for the Tarfa, Asyuti, Qena, and Hammamat alluvial aquifers are estimated at 4.7 x 10{sup 6} m{sup 3}, 6 x 10{sup 6} m{sup 3}, 14.7 x 10{sup 6} m{sup 3}, and 17.7 x10{sup 6} m{sup 3}, respectively. Implications for the use of these renewable ground waters and similar water resources in other arid areas of Egypt and in neighboring countries are clear.

Gheith, H.; Sultan, M.; Environmental Research

2002-06-10

86

Remote sensing detection of gold related alteration zones in Um Rus area, Central Eastern Desert of Egypt  

NASA Astrophysics Data System (ADS)

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Phased Array L-band Synthetic Aperture Radar (PALSAR) images covering the Um Rus area in the Central Eastern Desert of Egypt were evaluated for mapping geologic structure, lithology, and gold-related alteration zones. The study area is covered by Pan-African basement rocks including gabbro and granodiorite intruded into a variable mixture of metavolcanics and metasediments. The first three principal component analyses (PCA1, PCA2, PCA3) in a Red-Green-Blue (RGB) of the visible through shortwave-infrared (VNIR + SWIR) ASTER bands enabled the discrimination between lithological units. The results show that ASTER band ratios ((2 + 4)/3, (5 + 7)/6, (7 + 9)/8) in RGB identifies the lithological units and discriminates the granodiorite very well from the adjacent rock units.The granodiorites are dissected by gold-bearing quartz veins surrounded by alteration zones. The microscopic examination of samples collected from the alteration zones shows sericitic and argillic alteration zones. The Spectral Angle Mapper (SAM) and Spectral Information Divergence (SID) supervised classification methods were applied using the reference spectra of the USGS spectral library. The results show that these classification methods are capable of mapping the alteration zones as indicated by field verification work. The PALSAR image was enhanced for fracture mapping using the second moment co-occurrence filter. Overlying extracted faults and alteration zone classification images show that the N30E and N-S fractures represent potential zones for gold exploration. It is concluded that the proposed methods can be used as a powerful tool for ore deposit exploration.

Amer, Reda; Kusky, Timothy; El Mezayen, Ahmed

2012-01-01

87

Palaeoenvironmental history of Bap-Malar and Kanod playas of western Rajasthan, Thar desert  

Microsoft Academic Search

Two playas in the arid core of the western margin of the Thar desert viz., Bap-Malar and Kanod, have been investigated using\\u000a palynology, geomorphology, archaeology, AMS-radiocarbon dating, stable isotopes, evaporite mineralogy and geoarchaeology.\\u000a The principal objective was to obtain a reliable lithostratigraphy of the playa sediments. These are about 7 m thick in the\\u000a Bap-Malar and > 2.5 to 3

B. C. Deotare; M. D. Kajale; S. N. Rajaguru; S. Kusumgar; A. J. T. Jull; J. D. Donahue

2004-01-01

88

Late Neoproterozoic Nuqara Dokhan Volcanics, Central Eastern Desert, Egypt: Geochemistery and petrogenesis  

NASA Astrophysics Data System (ADS)

The Nuqara volcanic is one of the northernmost outcrops of the Arabian-Nubian Shield Dokhan volcanics. The origin and tectonic setting of the late Neoproterozoic Dokhan volcanics (ca. 610-560 Ma) in the Egyptian Eastern Desert is highly debated. The debate concerns the tectonic setting where they formed during transition between convergent to extensional regime or after the East- and the West-Gondwana collision (~600Ma). In order to solve this problem, lavas from Nuqara area were studied geologically and geochemically. Nuqara Dokhan volcanics comprises two main rock suites: (a) an intermediate volcanic suite, consisting of basaltic andesite, andesite and their associated pyroclastics rocks; and (b) a felsic volcanic suite composed of dacite, rhyolite and ignimbrites. The two suites display well-defined major and trace element trends and continuum in composition with wide ranges in SiO2 (52-75.73%), CaO (9.19-0.22%), MgO (5.29-0.05%), Sr (1367-7.4 ppm), Zr (688.5-172.7 ppm), Cr (207-0.4 ppm), and Ni (94.3-0.2 ppm). The Nuqara Dokhan volcanics are characterized by strong enrichment in LILE relative to HFSE and affiliated to the calc-alkaline subducted - related magmatism. Geochemical Modeling displays that the evolution of these rocks was governed by fractional crystallization of plagioclase, amphiboles, pyroxene, magnetite and apatite in the intermediate varieties and plagioclase, amphibole, magnetite, apatite and zircon in the felsic varieties. The obtained mineral chemistry of these volcanics reveals: (a) Plagioclase range in composition from An55 to An40 in basaltic andesite and from An39 to An24 in andesite. (b) Alkali feldspars have sanidine composition. (c) Clinopyroxenes have augite composition. The low Al2O3 contents (1.94-5.588 wt %) indicate that clinopyroxene crystallized at low - pressure conditions. (d) Amphiboles have magnesio- hornblende composition.

Hassan, Tharwat; Asran, Asran; Amron, Taha; Natflos, Theo

2014-05-01

89

Stratigraphy, sedimentology and tectonic evolution of the Upper Cretaceous/Paleogene succession in north Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The stratigraphy, sedimentology and syn-depositional tectonic events (SdTEs) of the Upper Cretaceous/Paleogene (K-P) succession at four localities in north Eastern Desert (NED) of Egypt have been studied. These localities are distributed from south-southwest to north-northeast at Gebel Millaha, at North Wadi Qena, at Wadi El Dakhal, and at Saint Paul Monastery. Lithostratigraphically, four rock units have been recorded: Sudr Formation (Campanian-Maastrichtian); Dakhla Formation (Danian-Selandian); Tarawan Formation (Selandian-Thanetian) and Esna Formation (Thanetian-Ypresian). These rock units are not completely represented all over the study area because some of them are absent at certain sites and others have variable thicknesses. Biostratigrapgically, 18 planktonic foraminiferal zones have been recorded. These are in stratigraphic order: Globotruncana ventricosa Zone (Campanian); Gansserina gansseri, Contusotruncana contusa, Recimguembelina fructicosa, Pseudohastigerina hariaensis, Pseudohastigerina palpebra and Plummerita hantkenenoides zones (Maastrichtian); Praemurica incostans, Praemurica uncinata, Morozovella angulata and Praemurica carinata/Igorina albeari zones (Danian); Igorina albeari, Globanomanlina pseudomenradii/Parasubbotina variospira, Acarinina subsphaerica, Acarinina soldadoensis/Globanomanlina pseudomenardii and Morozovella velascoensis zones (Selandian/Thantian); and Acarinina sibaiyaensis, Pseudohastigerina wilcoxensis/Morozovella velascoensis zones (earliest Ypresian). Sedimentologically, four sedimentary facies belts forming southwest gently-dipping slope to basin transect have been detected. They include tidal flats, outer shelf, slumped continental slope and open marine hemipelagic facies. This transect can be subdivided into a stable basin plain plus outer shelf in the extreme southwestern parts; and an unstable slope shelf platform in the northeastern parts. The unstable slope shelf platform is characterized by open marine hemipelagic, fine-grained limestones and fine siliciclastic shales (Sudr, Dakhla, Tarawan and Esna formations). The northeastern parts are marked by little contents of planktonic foraminifera and dolomitized, slumped carbonates, intercalated with basinal facies. Tectonically, four remarkable syn-depositional tectonic events (SdTEs) controlled the evolution of the studied succession. These events took place strongly within the Campanian-Ypresian time interval and were still active till Late Eocene. These events took place at: the Santonian/Campanian (S/C) boundary; the Campanian/Maastrichtian (C/M) boundary; the Cretaceous/Paleogene (K/P) boundary; and the Middle Paleocene-Early Eocene interval. These tectonic events are four pronounced phases in the tectonic history of the Syrian Arc System (SAS), the collision of the Afro-Arabian and Eurasian plates as well as the closure of the Tethys Sea.

El Ayyat, Abdalla M.; Obaidalla, Nageh A.

2013-05-01

90

Integrating geologic and satellite imagery data for high-resolution mapping and gold exploration targets in the South Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The granitoid-greenstone belts of the Arabian-Nubian Shield are well-endowed with lode gold and massive sulfide ores. Although generally characterized by excellent outcrops and arid desert realm, poor accessibility and lack of finance have been always retardant to detailed geologic mapping of vast areas of the shield. Lack of comprehensive geological information and maps at appropriate scales would definitely hinder serious exploration programs. In this study, band ratioing, principal component analysis (PCA), false-color composition (FCC), and frequency filtering (FFT-RWT) of ASTER and ETM+ data have substantially improved visual interpretation for detailed mapping of the Gebel Egat area in South Eastern Desert of Egypt. By compiling field, petrographic and spectral data, controls on gold mineralization have been assessed in terms of association of gold lodes with particular lithological units and structures. Contacts between foliated island arc metavolcanics and ophiolites or diorite are likely to be favorable loci for auriferous quartz veins, especially where the NW-SE foliation is deflected into steeply dipping NNW-trending shear planes. High-resolution mapping of the greenstone belt, structures and alteration zones associated with gold lodes in the study area suggests that dilatation by foliation deflection was related to emplacement of the Egat granitic intrusion, attendant with a sinistral transpression regime (i.e., ˜640-550 Ma?). Gold mineralization associated with granitoid intrusions in transpression-induced pull-apart structures elsewhere in the Eastern Desert (e.g., Fawakhir, Sukari and Hangaliya mines) emphasize the reliability of this setting as a model for gold exploration targets in greenstone terrains of Egypt, and may be elsewhere in the Arabian-Nubian Shield.

Zoheir, Basem; Emam, Ashraf

2012-05-01

91

The Predynastic of Egypt  

Microsoft Academic Search

The Predynastic of Egypt, spanning an interval from ca. 4000 to 3050 B.C., was an eventful period. After the inception of food production in the Nile Valley at least a millennium before, it was the time when the identity of Egyptian society was forged. Egypt was settled by refugees from the deserts of the eastern Sahara and the southern Levant,

Fekri A. Hassan

1988-01-01

92

Application of LANDSAT satellite imagery for iron ore prospecting in the western desert of Egypt  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. The delineation of the geological units and geological structures through image interpretation, corroborated by field observations and structural analysis, led to the discovery of new iron ore deposits. A new locality for iron ore deposition, namely Gebel Qalamun, was discovered, as well as new occurrences within the already known iron ore region of Bahariya Oasis.

Elshazly, E. M.; Abdel-Hady, M. A.; Elghawaby, M. A.; Khawasik, S. M. (principal investigators)

1977-01-01

93

Sedimentology of the middle Eocene Minia and Samalut Formations, West Beni Mazar, Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

The petrography of the middle Eocene Minia and Samalut Formations is discussed. The formations are subdivided into lithofacies denoting lateral as well as vertical facies changes. An environmental interpretation for these two formations is proposed. The lower portion of the Minia Formation was deposited in a shoal environment whilst the upper portion was deposited in a back reef environment. The Samalut Formation can be differentiated into the following subenvironments from south to north: shelf edge, shelf break mounds and fore slope talus.

Wahab, S. A.; Khalifa, M. A. G.

94

Application and calibration of the subsurface mapping capability of SIR-B in desert regions  

NASA Technical Reports Server (NTRS)

The penetration capability of the shuttle imaging radar (SIR-B) sensor in desert regions is investigated. Refined models to explain this penetration capability in terms of radar physics and regional geologic conditions are devised. The sand-buried radar-rivers discovered in the Western Desert in Egypt and Sudan are defined. Results and procedures developed during previous SIR-A investigation of the same area are extrapolated.

Schaber, G. G.; Mccauley, J. F.; Breed, C. S.; Grolier, M. J.; Issawi, B.; Haynes, C. V.; Mchugh, W.; Walker, A. S.; Blom, R.

1984-01-01

95

Western blot can distinguish natural and acquired antibodies to Mycoplasma agassizii in the desert tortoise (Gopherus agassizii).  

PubMed

Mycoplasma agassizi has been identified as a cause of upper respiratory tract disease (URTD) in the threatened Mojave population of the desert tortoise (Gopherus agassizii), and anti-M. agassizii antibodies have been found by ELISA in as many as 15% of these animals across their geographic range. Here we report that a cohort of 16 egg-reared desert tortoises never exposed to M. agassizii had ELISA antibody titers to this organism that overlapped with titers obtained from some M. agassizii-infected tortoises. These natural antibodies were predominantly of the IgM class. Western blots of plasma from these non-infected tortoises produced a characteristic banding pattern against M. agassizii antigens. A group of 38 wild-caught desert tortoises was tested by ELISA, and although some of these tortoises had antibody titers significantly higher than the non-infected tortoises, there was considerable overlap at the lower titer levels. However, Western blot analysis revealed distinct banding patterns that could readily distinguish between the non-infected tortoises and tortoises with acquired antibodies, regardless of ELISA antibody titers. We conclude that desert tortoises have natural antibodies to M. agassizii that can compromise the determination of infection status by ELISA. However, the Western blot technique can distinguish between natural and acquired antibody patterns and can be used to confirm the diagnosis of M. agassizii infections in the desert tortoise. PMID:18708096

Hunter, Kenneth W; Dupré, Sally A; Sharp, Tiffanny; Sandmeier, Franziska C; Tracy, C Richard

2008-12-01

96

Water quality and phytoplankton communities in Lake Qarun (Egypt)  

Microsoft Academic Search

Lake Qarun is a closed saline lake in the northern part of El-Fayoum Depression (Middle Egypt) at the margin of the Great Western Desert. It is almost entirely sustained by inflow from the Nile River and, during the 20th century, lake water salinity has increased strongly. Physico-chemical characteristics and phytoplankton periodicity in the lake were monitored during 2001. All the

Adel A. Fathi; Roger J. Flower

2005-01-01

97

Geothermal Resources of the Western Arm of the Black Rock Desert, Northwestern Nevada: Part 2, Aqueous Geochemistry and Hydrology.  

National Technical Information Service (NTIS)

The report describes the results of a study to examine the basic hydrologic and geochemical data and to evaluate the validity of integrated conceptual models of the geothermal resources in the western arm of the Black Rock Desert, northern Great Basin. Th...

A. H. Welch A. M. Preissler

1990-01-01

98

Geothermal resources of the western arm of the Black Rock Desert, northwestern Nevada. Part I. Geology and geophysics  

Microsoft Academic Search

Studies of the geothermal potential of the western arm of the Black Rock Desert in northwestern Nevada included a compilation of existing geologic data on a detailed map, a temperature survey at 1-meter depth, a thermal-scanner survey, and gravity and seismic surveys to determine basin geometry. The temperature survey showed the effects of heating at shallow depths due to rising

D. H. Schaefer; A. H. Welch; D. K. Maurer

1983-01-01

99

Estimation of heat generation by radioactive decay of some phosphate rocks in Egypt.  

PubMed

Radiogenic heat production data for phosphate rocks outcropping on the three main areas Eastern Desert, Western Desert and Nile Valley are presented. They were derived from uranium, thorium and potassium concentration measurements of gamma radiation originating from the decay of (214)Bi ((238)U series), (208)Tl ((232)Th series) and the primary decay of (40)K. A low radioactive heat production rate (0.32+/-0.1 microWm(-3)) was found for Wadi Hegaza, whereas the highest value (19+/-4.1 microWm(-3)) was found for Gabel Anz, Eastern Desert of Egypt. PMID:19186064

Din, Khaled Salahel

2009-11-01

100

Interstratified vermiculite-mica in the gneiss-metapelite-serpentinite rocks at Hafafit area, Southern Eastern Desert, Egypt: From metasomatism to weathering  

NASA Astrophysics Data System (ADS)

The Hafafit vermiculite in the Southern Eastern Desert of Egypt at the contact of the metapelite and serpentinite rocks with the pegmatites and gneisses of the Hafafit uplift is the only known deposit in the Arabian-Nubian Shield (ANS) rocks of the Eastern Desert (ED). It is distinctively interstratified with mica. The mineralogy and mineral chemistry of this vermiculite at four sites (HV1, HV2, HV3 and HV4) were studied to better understand its origin, which might refers to a specific geologic setting retained to Hafafit area. The vermiculite at Hafafit forms with phlogopite, actinolite-tremolite, asbestos-anthophyllite-talc and talc zones that are arranged from pegmatite and gneisses to the metapelite and serpentinite rocks. These zones were probably formed by metasomatism that related to the intrusion of the granitoid rocks and the connected pegmatites in the upper Pan-African. The XRD and EMPA studies of the interstratified vermiculite-mica concluded that vermiculitization took place through a layer-by-layer transformation of original micas. This formed, in decreasing abundance, mixed-layer phases of biotite/vermiculite (hydrobiotite), phlogopite/vermiculite (hydrophlogopite) and chlorite/vermiculite (corrensite) and discrete phases of vermiculite, chlorite and smectite. A model is suggested, in which chemical weathering by the moving downward meteoric water led to replacement of the interlayer K, in biotite from gneiss and in phlogopite from metasomatic zones, by H 2O molecules, Fe 2+ was oxidized and (OH) - replaced O 2- forming hydrobiotite and hydrophlogopite. By more K remove, Fe was replaced by Mg with the introduction of more layers of H 2O molecules leading to formation of the vermiculite. Weathering formed corrensite mixed-layer and chlorite expandable minerals on the expense of chlorite. Formation of the incomplete smectite-like layers and Al-hydroxy interlayers (13.97 ?) took place at the expense of vermiculite, replacing the Mg interlayer cations (12.63 ?). Weathering took place mostly by low-pH solutions and in warm environment and the most extensive degree of weathering was at the HV4 site, in which the lode of vermiculite is the biggest. We propose that vermiculitization at Hafafit occurred due to a specific integration between the geologic setting (including rock type and tectonics) of the area and weathering processes producing the only vermiculite deposit in the ANS rocks of the ED of Egypt.

Harraz, H. Z.; Hamdy, M. M.

2010-09-01

101

Late Pliocene age for the Atacama Desert: Implications for the desertification of western South America  

Microsoft Academic Search

The Atacama Desert forms one of the major hyperarid deserts of the world. Previous studies suggest that desertification commenced at 14 Ma during global climate desiccation. Sedimentologic data from middle Miocene to upper Pliocene successions in the modern Atacama Desert indicate that a semiarid climate persisted from 8 to 3 Ma, punctuated by a phase of increased aridity at ca.

Adrian J. Hartley; Guillermo Chong

2002-01-01

102

Chihuahuan Deserts Ecoregion: Chapter 27 in Status and trends of land change in the Western United States--1973 to 2000  

USGS Publications Warehouse

The Chihuahuan Desert is the largest of the North American deserts, extending from southern New Mexico and Texas deep into Mexico, with approximately 90 percent of its area falling south of the United States–Mexico border (Lowe, 1964, p. 24). The Chihuahuan Deserts Ecoregion covers approximately 174,472 km2 (67,364 mi2) within the United States, including much of west Texas, southern New Mexico, and a small portion of southeastern Arizona (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is generally oriented from northwest to southeast, with the Madrean Archipelago Ecoregion to the west; the Arizona/New Mexico Mountains, Arizona/New Mexico Plateau, Southwestern Tablelands, and Western High Plains Ecoregions to the north; and the Edwards Plateau and Southern Texas Plains Ecoregions to the east (fig. 1).

Ruhlman, Jana; Gass, Leila; Middleton, Barry

2012-01-01

103

RETRACTED: Geology and petrogenesis of Neoproterozoic migmatitic rock association, Hafafit Region, Eastern Desert, Egypt: Implications for syntectonic anatectic migmatites  

NASA Astrophysics Data System (ADS)

This article has been retracted at the request of the Editor-in-Chief and Author. Please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy). Reason: This article was essentially a duplication of a paper that had already appeared in Egypt. J. Geol., 52 (2008) 25-54. The author would like to apologize for a misunderstanding on his part that led him to believe that the publication of the paper in a local journal and Lithos, without prior agreement with both journals and clear notification, did not represent duplicate publication.

El Bahariya, Gaafar

2009-12-01

104

Carbonate-orthopyroxenite lenses from the Neoproterozoic Gerf ophiolite, South Eastern Desert, Egypt: The first record in the Arabian Nubian Shield ophiolites  

NASA Astrophysics Data System (ADS)

Carbonate-orthopyroxenites (classic sagvandites) are reported in the Gerf ophiolite, South Eastern Desert, Egypt: the first finding from the Arabian Nubian Shield (ANS) ophiolites. They form massive lenses at the southern tip of the Gerf ophiolite, along the contact between the Shinai granite and Gerf serpentinized peridotites. The lenses show structural concordance with the neighboring country rocks and the granite contact. They consist mainly of metamorphic orthopyroxene + magnesite, among other metamorphic, relict primary and retrograde secondary minerals. Based only on chemistry, two types of carbonate-orthopyroxenites can be recognized, Types I (higher-Mg) and II (lower-Mg and higher-Fe). Field constraints, petrography and mineral chemistry indicate a metamorphic origin for the Gerf carbonate-orthopyroxenites. The euhedral form of relict primary chromian spinels combined with their high Cr#/low-TiO 2 character, and absence of clinopyroxene suggest that the protolith for the Gerf carbonate-orthopyroxenites is a highly depleted mantle peridotite derived from a sub-arc setting. Contact metamorphism accompanied by CO 2-metasomatism resulted in formation of the Gerf carbonate-orthopyroxenites during intrusion of the Shinai granite. The source of CO 2-rich fluids is most likely the neighboring impure carbonate layers. Correlation of the carbonate-orthopyroxenite mineral assemblages with experimental data for the system MgO-SiO 2-H 2O-CO 2 suggests metamorphic/metasomatic conditions of 520-560 °C, Pfluid = 2 kbar and extremely high X values (0.87-1).

Gahlan, Hisham A.; Arai, Shoji

2009-01-01

105

Thermodynamic modelling of Sol Hamed serpentinite, South Eastern Desert of Egypt: implication for two serpentinization stages in the Arabian-Nubian Shield ophiolites  

NASA Astrophysics Data System (ADS)

The Arabian-Nubian Shield is the largest tract of juvenile continental crust of Neoproterozoic age on Earth. This crust was generated due to arc-arc collision associated with the closing of the Mozambique Ocean. Distribution of ophiolitic rocks marks fossils suture zones in the shield. Petrological, mineral chemistry, whole-rock chemistry and thermodynamic studies are carried out to examine the serpentinite component of Sol Hamed ophiolite in south Eastern Desert of Egypt. The protolith mantle was harzburgite and formed in subduction zone of forearc setting. Serpentinization occurred in two stages. The first by intrusion of high concentrated CO2 fluid released from carbonate-bearing sediments and altered basalt at the subduction zone. The serpentinization achieved during isobaric cooling path at pressure of 1 kbar and before the emplacement. The minimum temperature limit of the serpentinization is above the breakdown of lizardite to antigorite and brucite (170 °C). The fluid composition during the isobaric cooling path was buffered by the metamorphic reactions. The second stage of serpentinization took place through prograde path which led to formation of chrysotile after lizardite. The increasing in the pressure during this stage occurred as a result of extensive duplex array and thrusting of oceanic crust. The crust in the forearc basin was overloaded by 28 km of obducted and thrusted oceanic crust from both mid-oceanic and forearc basins, respectively.

Abu-Alam, T.; Hamdy, M.

2012-04-01

106

Numbers, foraging and refuelling of passerine migrants at a stopover site in the western Sahara: diverse strategies to cross a desert  

Microsoft Academic Search

Twice a year, songbirds breeding in the Western Palaearctic cross the largest desert of the world, the Sahara, to reach their\\u000a African winter quarters. Recently, a radar study quantified this migration and demonstrated that almost all passerines cross\\u000a the western Sahara with an intermittent strategy, i.e. they fly during the night and rest during the day. Before crossing\\u000a the desert,

Susanne Jenni-Eiermann; Bettina Almasi; Ivan Maggini; Volker Salewski; Bruno Bruderer; Felix Liechti; Lukas Jenni

107

Geothermal resources of the western arm of the Black Rock Desert, northwestern Nevada. Part I. Geology and geophysics  

SciTech Connect

Studies of the geothermal potential of the western arm of the Black Rock Desert in northwestern Nevada included a compilation of existing geologic data on a detailed map, a temperature survey at 1-meter depth, a thermal-scanner survey, and gravity and seismic surveys to determine basin geometry. The temperature survey showed the effects of heating at shallow depths due to rising geothermal fluids near the known hot spring areas. Lower temperatures were noted in areas of probable near-surface ground-water movement. The thermal-scanner survey verified the known geothermal areas and showed relatively high-temperature areas of standing water and ground-water discharge. The upland areas of the desert were found to be distinctly warmer than the playa area, probably due to the low thermal diffusivity of upland areas caused by low moisture content. Surface geophysical surveys indicated that the maximum thickness of valley-fill deposits in the desert is about 3200 meters. Gravity data further showed that changes in the trend of the desert axis occurred near thermal areas. 53 refs., 8 figs., 3 tabs.

Schaefer, D.H.; Welch, A.H.; Maurer, D.K.

1983-01-01

108

Effects of protective fencing on birds, lizards, and black-tailed hares in the Western Mojave Desert  

USGS Publications Warehouse

Effects of protective fencing on birds, lizards, black-tailed hares (Lepus californicus), perennial plant cover, and structural diversity of perennial plants were evaluated from spring 1994 through winter 1995 at the Desert Tortoise Research Natural Area (DTNA), in the Mojave Desert, California. Abundance and species richness of birds were higher inside than outside the DTNA, and effects were larger during breeding than wintering seasons and during a high than a low rainfall year. Ash-throated flycatchers (Myiarchus cinerascens), cactus wrens (Campylorhynchus brunneicapillus), LeConte's thrashers (Toxostoma lecontei), loggerhead shrikes (Lanius ludovicianus), sage sparrows (Amphispiza belli), and verdins (Auriparus flaviceps) were more abundant inside than outside the DTNA. Nesting activity was also more frequent inside. Total abundance and species richness of lizards and individual abundances of western whiptail lizards (Cnemidophorous tigris) and desert spiny lizards (Sceloporus magister) were higher inside than outside. In contrast, abundance of black-tailed hares was lower inside. Structural diversity of the perennial plant community did not differ due to protection, but cover was 50% higher in protected areas. Black-tailed hares generally prefer areas of low perennial plant cover, which may explain why they were more abundant outside than inside the DTNA. Habitat structure may not affect bird and lizard communities as much as availability of food at this desert site, and the greater abundance and species richness of vertebrates inside than outside the DTNA may correlate with abundances of seeds and invertebrate prey.

Brooks, M.

1999-01-01

109

Mesozoic evolution of northeast African shelf margin, Libya and Egypt  

SciTech Connect

The present tectonic features of the northeast African shelf margin between the Nile delta and the Gulf of Sirte are products of (1) precursory late Paleozoic basement arches, (2) early Mesozoic rifting and plate separation, and (3) Late Cretaceous structural inversion. The 250 km-wide and highly differentiated Mesozoic passive margin in the Western Desert region of Egypt is developed above a broad northwest-trending Late Carboniferous basement arch. In northeastern Libya, in contrast, the passive margin is restricted to just the northernmost Cyrenaica platform, where subsidence was extremely rapid in the Jurassic and Early Cretaceous. The boundary between the Western Desert basin and the Cyrenaica platform is controlled by the western flank of the basement arch. In the middle Cretaceous (100-90 Ma), subsidence accelerated over large areas of the Western desert, further enhancing a pattern of east-west-trending subbasins. This phase of rapid subsidence was abruptly ended about 80 Ma by the onset of structural inversion that uplifted the northern Cyrenaica shelf margin and further differentiated the Western Desert subbasin along a northeasterly trend.

Aadland, R.K.; Schamel, S.

1989-03-01

110

Bistatic GPR Measurements in the Egyptian Western Desert - Measured and Simulated data  

NASA Astrophysics Data System (ADS)

The TAPIR (Terrestrial And Planetary Investigation Radar) instrument has been designed at CETP (Centre d'etude des Environnements Terrestre et Planetaires) to explore the deep Martian subsurface (down to a few kilometers) and to detect liquid water reservoirs. TAPIR is an impulse ground penetrating radar operating at central frequencies ranging from 2 to 4 MHz operating from the surface. In November 2005, an updated version of the instrument working either in monostatic or in bi-static mode was tested in the Egyptian Western Desert. The work presented here focuses on the bi-static measurements performed on the Abou Saied plateau which shows a horizontally layered sub-surface. The electromagnetic signal was transmitted using one of the two orthogonal 70 m loaded electrical dipole antennas of the transmitting GPR. A second GPR, 50 or 100 meters apart, was dedicated to the signal reception. The received waves were characterized by a set of 5 measurements performed on the receiving GPR : the two horizontal components of the electric field and the three composants of the magnetic field. They were used to compute the direction of arrival of the incoming waves and to retrieve more accurately their propagation path and especially to discriminate between waves due to some sub-surface reflecting structure and those due to interaction with the surface clutter. A very efficient synchronization between the two radars enabled us to perform coherent additions up to 2^{31} which improves dramatically the obtained signal to noise ratio. Complementary electromagnetic measurements were conducted on the same site by the LPI (Lunar and Planetary Institute) and the SwRI (Southwest Research Institute). They provided independent information which helped the interpretation of the TAPIR data. Accurate simulations obtained by FDTD taking into account the information available are presented and used for both the interpretation of the measured data and the validation of the instrument.

Ciarletti, V.; Le Gall, A.; Berthelier, J.; Ney, R.; Corbel, C.; Dolon, F.

2006-12-01

111

Sex pheromone of the saturniid moth, Hemileuca burnsi, from the western Mojave Desert of California.  

PubMed

The sex pheromone blend of Hemileuca burnsi (Lepidoptera: Saturniidae) from the western Mojave Desert was determined to be a combination of (10E,12Z)-hexadecadien-1-yl acetate (E10,Z12-16:Ac), (10E,12Z)-hexadecadien-1-ol (E10,Z12-16:OH), (10E,12E)-hexadecadien-1-yl acetate (E10,E12-16:Ac), and hexadecyl acetate (16:Ac). (10E,12Z)-Hexadecadienal (E10,Z12-16:Ald) was tentatively identified in pheromone gland extracts based on electroantennographic responses and, when added to the above blend, it enhanced trap captures at low doses. The mean ratio of the compounds in extracts of pheromone glands was 100:23:232:14:0.4 (E10,Z12-16:Ac: E10,E12-16:Ac: 16:Ac: E10,Z12-16:OH: E10,Z12-16:Ald). Field trials indicated that although E10,Z12-16:Ac and E10,Z12-16:OH were essential for attraction, the two-component blend was not attractive by itself. Addition of the three other compounds was necessary for maximum attraction, rendering this the most complicated pheromone blend described for a Hemileuca species to date. Similarities between the sex pheromone of H. burnsi and that of the allopatric Hemileuca electra electra and differences between the blends of H. burnsi and that of the sympatric H. electra mojavensis support a case for reproductive character displacement in the pheromone communication channel of H. electra. PMID:18649103

McElfresh, J Steven; Millar, Jocelyn G

2008-09-01

112

Unique chemistry of a diamond-bearing pebble from the Libyan Desert Glass strewnfield, SW Egypt: Evidence for a shocked comet fragment  

NASA Astrophysics Data System (ADS)

We have studied a small, very unusual stone, here named "Hypatia", found in the area of southwest Egypt where an extreme surface heating event produced the Libyan Desert Glass 28.5 million years ago. It is angular, black, shiny, extremely hard and intensely fractured. We report on exploratory work including X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy with EDS analysis, deuteron nuclear reaction analysis, C-isotope and noble gas analyses. Carbon is the dominant element in Hypatia, with heterogeneous O/C and N/C ratios ranging from 0.3 to 0.5 and from 0.007 to 0.02, respectively. The major cations of silicates add up to less than 5%. The stone consists chiefly of apparently amorphous, but very hard carbonaceous matter, in which patches of sub-?m diamonds occur. ?13C values (ca. 0‰) exclude an origin from shocked terrestrial coal or any variety of terrestrial diamond. They are also higher than the values for carbonaceous chondrites but fall within the wide range for interplanetary dust particles and comet 81P/Wild2 dust. In step heating, 40Ar/36Ar ratios vary from 40 to the air value (298), interpreted as a variable mixture of extraterrestrial and atmospheric Ar. Isotope data of Ne, Kr and Xe reveal the exotic noble gas components G and P3 that are normally hosted in presolar SiC and nanodiamonds, while the most common trapped noble gas component of chondritic meteorites, Q, appears to be absent. An origin remote from the asteroid belt can account for these features.

Kramers, Jan D.; Andreoli, Marco A. G.; Atanasova, Maria; Belyanin, Georgy A.; Block, David L.; Franklyn, Chris; Harris, Chris; Lekgoathi, Mpho; Montross, Charles S.; Ntsoane, Tshepo; Pischedda, Vittoria; Segonyane, Patience; Viljoen, K. S. (Fanus); Westraadt, Johan E.

2013-11-01

113

The VLF EM Method Used for Verification of Fracture/ Shear Zone Aquifers in the Hyper-arid Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

An integrated program using Landsat remote sensing and ground follow-up with the Very Low Frequency (VLF) geophysical method was applied to the basement rocks of the Red Sea Hills (Eastern Desert) to locate fracture and shear-system aquifers. This part of the Nubian Shield was formed by accretion of a complex of ensimatic and ensialic island arcs and interleaving oceanic basins that were later accreted against the old African continent. Hence, melange and ophiolite sequences are common. This basement complex was intensely fractured (630- 530 Mybp) by the Najd transcurrent shear system (NSS) along a NW-SE trend that is up to 350 km wide, and finally the ocean-arc complex was intruded (~550 Mybp) by anorogenic K-granites. A false-color composite image was created, from Landsat thematic mapper band ratio images that are sensitive to the Fe-bearing aluminosilicate, hydroxyl, and opaque phase content of rocks. On these images mafic rocks (e.g., gabbro and mafic volcanics) rich in Fe-bearing aluminosilicates appear in shades of blue, ultramafics (e.g., serpentinites) rich in hydroxyl-bearing phases and opaque phases appear in shades of red, and granitoid rock units poor in the above phases show as green areas. Using this base map (effectively a pseudo geologic map) and a co-registered DEM, locations of potential shallow water occurrence were plotted based on the following criteria: 1) intersection of the NSS system with transverse faults defining wadis, 2) intersection of two or more fault zones, 3) within highly deformed melange units, especially their internal lithologic contacts and their crossings of wadis, 4) relatively unfractured younger dikes and their intersections with wadis. The VLF instrument was first used to make profiles at a number of existing water wells located at the structural intersections described above, to verify that sub-vertical sheet-like electrical conductors (water-filled fissures) could be successfully located with this instrument. Then, other sites that had been marked as having high potential for water using one or more of the above criteria were visited and profiled with the VLF. Many (but not all) of these sites gave anomalies characteristic of conductive fissures. Finally, several sites not chosen by the GIS interpreters were selected at random and profiled with the VLF. One of these (albeit adjacent to a melange area) did show a good conductor. Field navigation was directly on the scrolling false-color image on a laptop computer, linked to an active GPS receiver. VLF transmitters used were mainly those in Europe. Fourteen sites were visited in five days and nineteen total profiles were surveyed, ranging from 160 to 1200 meters in length. In summary, this methodology, beginning with satellite imagery and GIS, and ending with transects on foot with a VLF, proved to be a useful technique in such desert landscapes where fractured bedrock aquifers occur and the discovery of even a low-yield local aquifer is very important.

Sauck, W. A.; Sultan, M.; Wagdy, A.; Roouf, O. A.

2007-05-01

114

Bionomics of malaria vectors in two physiographically different areas of the epidemic-prone Thar Desert, north-western Rajasthan (India)  

Microsoft Academic Search

Entomological and parasitological investigations were carried out on malaria vectors and disease prevalence in two sets of villages, the highly irrigated Indira Gandhi Nahar Pariyojana (IGNP) command-area villages (Madassar and Awai), and the truly desertic non-command (unirrigated) area villages (Kanasar and Khetusar), located in different ecological conditions in the Thar Desert, north-western Rajasthan (India). Malaria prevalence, as determined through sustained

B. K Tyagi; S. P Yadav

2001-01-01

115

Oil and gas exploration in Egypt past, present, and future  

SciTech Connect

Egypt was among the early countries in which exploration for hydrocarbons took place. Back to 1886 when the first oil discovery was achieved and since then exploration operations were carried out covering almost every prospective area in Egypt. The history of oil exploration in Egypt passed through six stages, each of which is characterized by its own activities and reflects the impact of certain developments not only in the applied exploration techniques, but also in the work style and prevailing exploration concepts, in addition to the development in the agreement terms. Six areas could add new oil and gas reserves to Egypt, namely: N. Sinai (onshore and offshore); Nile Delta (onshore and offshore); Western Desert (onshore and offshore); Nile Valley; Red Sea; and the Gulf of Aqaba. Such areas have the prerequisites for commercial oil and/or gas accumulations including potential source rocks, good reservoirs and adequate traps in addition to effective seals. It is believed that the undiscovered oil and gas reserves of Egypt could be several times that which have been discovered so far.

Halim, M.A.

1995-08-01

116

Geotectonic significance of Neoproterozoic amphibolites from the Central Eastern Desert of Egypt: A possible dismembered sub-ophiolitic metamorphic sole  

NASA Astrophysics Data System (ADS)

Supra-subduction zone ophiolites in the Egyptian Central Eastern Desert (CED) occur as clusters in its northern (NCEDO) and southern (SCEDO) parts, displaying abundant island arc-boninitic and MORB/island-arc geochemical affinities, respectively. An amphibolite belt, including the investigated massive to slightly foliated Wadi Um Gheig (WUG) amphibolites, is exposed in the southeast most of the NCEDO thrusting over the El Sibai gneissic association and intruded by late- to post-orogenic granitoids and gabbros. The WUG rocks are metamorphosed under epidote amphibolite to common amphibolite facies. The amphiboles are calcic and represented by actinolitic hornblende to magnesio-hornblende in the epidote amphibolites and magnesio- to ferro-hornblende in the amphibolites. Plagioclase composition varies from pure albite (An 3-8) in the epidote amphibolites to andesine and labradorite (An 36-65) in the amphibolites. The estimated P-T conditions are in favor of their metamorphism under epidote amphibolite (c. 550-600 °C and 2-3 ± 1.5 kbar) and amphibolite (c. 618-720 °C and 3-6 ± 1.5 kbar) facies. The peak metamorphic conditions point to a burial depth of c.15-20 km. Geochemically, the WUG amphibolites show basaltic to andesitic compositions of tholeiitic affinity. They display LILE-enriched MORB-normalized patterns with negative Nb anomalies characteristic of the subduction-related rocks. However, their chondrite-normalized rare-earth element (REE) patterns vary from LREE-depleted (La N/Yb N = 0.29 to 0.49) to LREE-enriched (La N/Yb N = 2.97 to 3.74). Few samples show major and trace element contents typical of boninitic rocks, including U-shaped REE pattern. On the standard tectonic discrimination diagrams the WUG amphibolites plot mostly in the island-arc fields with some samples of MORB and boninitic affinities. Greenschist facies metamorphosed NCEDO obviously share these geochemical characteristics, implying formation in the same tectonic environment, i.e. forearc basin. This argues that the WUG amphibolites likely represent remnants of a dismembered metamorphic sole beneath the NCEDO. Their formation possibly involves intra-forearc basin thrusting followed by emplacement of ophiolite as imbricated stack of dismembered thrust slices in an accretionary wedge setting. This revives interests in geotectonic model in which the CED represents a forearc-arc-back-arc system above a southeast-dipping subduction zone.

Farahat, E. S.

2011-07-01

117

Potential of Electricity Generation on the Western Coast of Mediterranean Sea in Egypt  

NASA Astrophysics Data System (ADS)

A technical and economic assessment has been made of the electricity generation by wind turbines located at three promising potential wind sites: Sidi Barrani, Mersa Matruh and El Dabaa in the extreme northwest of Egypt along the Mediterranean Sea. These contiguous stations along the coast have an annual mean wind speed greater than 5.0 m/s at a height of 10 m. Weibull's parameters and the power law coefficient for all seasons have been estimated and used to describe the distribution and behavior of seasonal winds at these stations. The annual values of wind potential at the heights of 70-100 m above the ground level were obtained by extrapolation of the 10 m data from the results of our previous work using the power law. The three stations have a high wind power density, ranging from 340-425 to 450-555 W/m2 at the heights of 70-100 m, respectively. In this paper, an analysis of the cost per kWh of electricity generated by two different systems has been made: one using a relatively large single 2 MW wind turbine and the other - 25 small wind turbines (80 kW, total 2 MW) arranged in a wind farm. The yearly energy output of each system at each site was determined, and the electricity generation costs in each case were also calculated and compared with those at using diesel oil, natural gas and photovoltaic systems furnished by the Egyptian Electricity Authority. The single 2 MW wind turbine was found to be more efficient than the wind farm. For all the three considered stations the electricity production cost was found to be less than 2 ? cent/kWh, which is about half the specific cost of the wind farm.

Ahmed Shata, A. S.; Abdelaty, S. M.; Hanitsch, R.

2008-01-01

118

The use of multifrequency and polarimetric SIR-C\\/X-SAR data in geologic studies of Bir Safsaf, Egypt  

Microsoft Academic Search

Bir Safsaf, within the hyperarid “core” of the Sahara in the Western Desert of Egypt, was recognized following the SIR-A and SIR-B missions in the 1980s as one of the key localities in northeast Africa, where penetration of dry sand by radar signals delineates previously unknown, sand-buried paleodrainage valleys (“radar-rivers”) of middle Tertiary to Quaternary age. The Bir Safsaf area

Gerald G. Schaber; John F. McCauley; Carol S. Breed

1997-01-01

119

Integrated geoelectrical survey for groundwater and shallow subsurface evaluation: case study at Siliyin spring, El-Fayoum, Egypt  

Microsoft Academic Search

Siliyin spring is one of the many natural fresh water springs in the Western Desert of Egypt. It is located at the central\\u000a part of El-Fayoum Delta, which is a potential place for urban developments and touristic activities. Integrated geoelectrical\\u000a survey was conducted to facilitate mapping the groundwater resources and the shallow subsurface structures in the area. Twenty-eight\\u000a transient electromagnetic

Mohamed Metwaly; Gad El-Qady; Usama Massoud; Abeer El-Kenawy; Jun Matsushima; Nasser Al-Arifi

2010-01-01

120

Morphologic-anthropological investigations in tomb K93.12 at Dra' Abu el-Naga (Western Thebes, Egypt).  

PubMed

In this study we present the analysis of the human remains from tomb K93.12 in the Ancient Egyptian necropolis of Dra' Abu el-Naga, located opposite the modern city of Luxor in Upper Egypt on the western bank of the Nile. Archaeological findings indicate that the rock tomb was originally built in the early 18th dynasty. Remains of two tomb-temples of the 20th dynasty and the looted burial of the High Priest of Amun Amenhotep have been identified. After the New Kingdom the tomb was reused as a burial place until the 26th dynasty. The skeletal and mummified material of the different tomb areas underwent a detailed anthropological and paleopathological analysis. The human remains were mostly damaged and scattered due to extensive grave robberies. In total, 79 individuals could be partly reconstructed and investigated. The age and sex distribution revealed a male predominance and a high percentage of young children (< 6 years) and adults in the range of 20 to 40 years. The paleopathological analysis showed a high prevalence of stress markers such as cribra orbitalia in the younger individuals, and other pathological conditions such as dental diseases, degenerative diseases and a possible case of ankylosing spondylitis. Additionally, 13 mummies of an intrusive waste pit could be attributed to three different groups belonging to earlier time periods based on their style of mummification and materials used. The study revealed important information on the age and sex distribution and diseases of the individuals buried in tomb K93.12. PMID:24818442

Lösch, Sandra; Moghaddam, Negahnaz; Paladin, Alice; Rummel, Ute; Hower-Tilmann, Estelle; Zink, Albert

2014-01-01

121

Geothermal resources of the western arm of the Black Rock Desert, northwestern Nevada: Part 2, aqueous geochemistry and hydrology. Water Resources Investigation  

Microsoft Academic Search

The report describes the results of a study to examine the basic hydrologic and geochemical data and to evaluate the validity of integrated conceptual models of the geothermal resources in the western arm of the Black Rock Desert, northern Great Basin. The most significant aspects of the study were: (1) The hydrologic connection, if any, between and among the various

A. H. Welch; A. M. Preissler

1990-01-01

122

Implications of high altitude desert dust transport from Western Sahara to Nile Delta during biomass burning season.  

PubMed

The air over major cities and rural regions of the Nile Delta is highly polluted during autumn which is the biomass burning season, locally known as black cloud. Previous studies have attributed the increased pollution levels during the black cloud season to the biomass or open burning of agricultural waste, vehicular, industrial emissions, and secondary aerosols. However, new multi-sensor observations (column and vertical profiles) from satellites, dust transport models and associated meteorology present a different picture of the autumn pollution. Here we show, for the first time, the evidence of long range transport of dust at high altitude (2.5-6 km) from Western Sahara and its deposition over the Nile Delta region unlike current Models. The desert dust is found to be a major contributor to the local air quality which was previously considered to be due to pollution from biomass burning enhanced by the dominant northerly winds coming from Europe. PMID:20797813

Prasad, Anup K; El-Askary, Hesham; Kafatos, Menas

2010-11-01

123

Subduction-related cryptic metasomatism in fore-arc to nascent fore-arc Neoproterozoic mantle peridotites beneath the Eastern Desert of Egypt: mineral chemical and geochemical evidences  

NASA Astrophysics Data System (ADS)

Mantle spinel peridotites beneath the Arabian Nubian Shield (ANS) in the Eastern Desert (ED) of Egypt were formed in arc stage in different tectonic setting. Thus they might subject to exchange with the crustal material derived from recycling subducting oceanic lithosphere. This caused metasomatism enriching the rocks in incompatible elements and forming non-residual minerals. Herein, we present mineral chemical and geochemical data of four ophiolitic mantle slice serpentinized peridotites (W. Mubarak, G. El-Maiyit, W. Um El Saneyat and W. Atalla) widely distributed in the ED. These rocks are highly serpentinized, except some samples from W. Mubarak and Um El-Saneyat, which contain primary olivine (Fo# = 90-92 mol %) and orthopyroxene (En# = 86-92 mol %) relics. They have harzburgite composition. Based on the Cr# and Mg# of the unaltered spinel cores, all rocks formed in oceanic mantle wedge in the fore-arc setting, except those from W. Atalla formed in nascent fore-arc. This implies that the polarity of the subduction during the arc stage was from the west to the east. These rocks are restites formed after partial melting between 16.58 in W. Atalla to 24 % in G-El Maiyit. Melt extraction occurred under oxidizing conditions in peridotites from W. Mubarak and W. Atalla and under reducing conditions in peridotites from G. El-Maiyit and Um El-Saneyat. Cryptic metasomatism in the studied mantle slice peridotites is evident. This includes enrichment in incompatible elements in minerals and whole rocks if compared with the primitive mantle (PM) composition and the trend of the depletion in melt. In opx the Mg# doesn't correlate with TiO2, CaO, MnO, NiO and Cr2O3concentrations. In addition, in serpentinites from W. Mubarak and W. Atalla, the TiO2spinel is positively correlated with the TiO2 whole-rock, proposing enrichment by the infiltration of Ti-rich melts, while in G. El- Maiyit and Um El-Saneyat serpentinites they are negatively correlated pointing to the reaction with the Ti-rich melts. All rocks are enriched LREE, FMEs and HFSEs. This took place mostly by different agents. As the H2O-rich liquid, which seems to have been produced from the subducting oceanic slab percolating peridotites, gradually loses trace elements, the HFSEs are fractionated from LILEs and REEs. This could explain the high ratios of (Nb/La)N and (Nb/Ba)N of some of the studied rocks. All the studied serpentinized mantle slices have subchonddritic to near chondritic ratios of Nb/Ta (< 13.8) and Zr/ Hf (< 36.09). It is suggested that Nb did not fractionate from Ta and Zr from Hf. There are might be silicate melts enriched the peridotites in Ta rather than Nb causing a much great decrease in the Nb/Ta especially serpentinites from W. Mubarak. This melt/fluid might have been derived from recycled subducted oceanic crust or from hot asthenosphere. Concentrations of U in all the studied samples (except for W. Mubarak serpentinites) are positively correlated with LILEs, Pb and Mo, indicating that the studied serpentinites were enriched in these elements from the same fluids, most probably derived from subducted oceanic lithosphere. Positive anomalies of Li (in W. Mubarak and G. El-Maiyit serpentinites), U (except for W. Mubarak serpentinites), Mo and Pb are characteristics of hydrothermally altered ocean-floor peridotites. High Sr/Nd ratios may be typical of the hydrous metasomatism caused by hydrous melt/fluid.

Hamdy, Mohamed; Salam Abu El-Ela, Abdel; Hassan, Adel; Kill, Youngwoo; Gamal El Dien, Hamed

2013-04-01

124

Westward prograding metamorphism in mantle peridotites from the Eastern Desert of Egypt: clues to the subduction polarity of the Arabian Nubian Shield intra-oceanic arc ophiolite  

NASA Astrophysics Data System (ADS)

Neoproterozoic arc mantle beneath the Arabian Nubian Shield (ANS) in the Eastern Desert (ED) of Egypt exhumed due to intra-oceanic upthrusting are represented mainly by exposed ophiolitic peridotites serpentinized to different degree. Metamorphism is related to the Pan-African collision and the subduction of oceanic lithosphere. However, polarity of the Pan-African intra-oceanic subduction is still questionable. We here trace the variation of the degree of serpentinization and regional metamorphism of six serpentinite masses, widely distributed in the ED (from the east to the west: W (Wadi). Alam, W. Igla, W. Mubarak, G. El-Maiyit, W. Um El Saneyat and W. Atalla). This is based on their mineralogy, textures and mineral chemistry. The studied rocks have harzburgite composition and they all formed in oceanic mantle wedge in the fore-arc setting, except those from W. Atalla that formed in MOR-arc transition setting. Much difference in the degree of serpentinization is obvious among these rocks. They are mainly partly serpentinized containing primary olivine and orthopyroxene at W. Alam and W. Igla, while they are completely serpentinized in the other localities. With the increased degree of metamorphism, textures were transformed from the pseudomorphic to the non-pseudomorphic. The most common retrograde assemblage is composed of lizardite ± chrysotile± brucite± magnetite. The serpentine prograde textures can be viewed as a continuum from retrograde lizardite pseudomorphic textures, to very fine-grained transitional texture of lizardite and chrysotile, to chrysotile-antigorite interlocking texture and finally to antigorite interpenetrating texture. These textures appear to represent successive stages in a recrystallization event. In late subduction-related metamorphism and early collisional emplacement stage, mylonitic-antigorite serpentinites formed and antigorite became the major phase in G. El-Maiyit, Um El-Saneyat and W. Atalla. The polygonal units of the hourglass texture and the penetrative fabric of the serrate veins in all serpentinized peridotites indicate that fracturing of these rocks was developed in a dynamic regime. The late emplacement of veins of brucite, carbonates and oxides were most probably formed during the final stage of exhumation and under a stress regime in the brittle-ductile transition. As the grade of metamorphism increases Fe released from olivine and orthopyroxene and Cr released from chromite are accommodating in antigorite-rich serpentinites. Serpentine in veins also tends to have less substitutions, which is consistent with the fact that Al, Cr and Ni are relatively immobile during alteration and therefore remain in their original microstructural site. Compositional zoning in spinel grains in all serpentinites reflect variation in the degree of alteration. The biggest variation of spinel compositions are among serpentinites from Um El-Saneyat and W. Atalla. With increasing the degree of alteration, size of the aluminian chromite core decreases while width of the intermediate Fe3+-rich aluminian chromite to ferrian-chromite zone and the outer Cr-magnetite to magnetite zones increase. The alteration zones were formed in a temperature < 400 ° C to 550 ° C corresponding to the low green-schist to the lower amphibolite facies. We propose that this is concordant with a westward polarity of the subducting oceanic lithosphere, associating the intra-oceanic arc ophiolite during the closure of the Mozambique ocean.

Salam Abu El-Ela, Abdel; Hamdy, Mohamed; Abu-Alam, Tamer; Hassan, Adel; Gamal El Dien, Hamed

2013-04-01

125

Microbiotic crusts and their interrelations with environmental factors in the Gurbantonggut desert, western China  

NASA Astrophysics Data System (ADS)

Located in the Junggar Basin in Xinjiang, the Gurbantonggut Desert is the second largest desert in China. Microbiotic crusts consisting of animalcule, lichen, moss, and algae species develop extensively in the region. Their formation, species composition and distribution pattern are closely related to the environmental conditions along the different parts of sand dune. Analysis of microbiotic crust distribution and relationship to environmental factors shows that average microbiotic crust thickness is 0.05 0.1 cm at the tops dunes, 0.2 1.5 cm in the upper part, 1.5 2.5 cm in middle and lower parts of dunes, and 1.5 5.0 cm in interdune areas, while areal coverage is 30.5, 48.5, 55.5, and 75.5%, respectively. Microbiotic crust differentiation along dune slopes is a result of the development stage and converse-succession resistance of the different microbiotic crusts. The numbers of species, thickness and degree of development of microbiotic crusts increase from the upper part to the middle and lower parts of dune slopes. The development and differentiation of microbiotic crusts at various dune slope positions are a reflection of the ecological expression of the comprehensive adaptability and natural selection of different microbiotic crust species to the local environmental conditions, and are closely related to such ecological conditions as the physiochemical properties of soils and topsoil textural stability.

Chen, Y. N.; Wang, Q.; Li, W. H.; Ruan, X.

2007-04-01

126

Paleomagnetism of middle Miocene volcanic rocks in the Mojave-Sonora desert region of western Arizona and southeastern California  

SciTech Connect

Paleomagnetic directions have been obtained from 190 early to middle Miocene (12-20 Ma) mafic volcanic flows in 16 mountain ranges in the Mojave-Sonora desert region of western Arizona and southeastern California. These flows generally postdate early Miocene tectonic deformation accommodated by low-angle normal faults but predate high-angle normal faulting in the region. After detailed demagnetization experiments, 179 flows yielded characteristic directions interpreted as original thermal remanent magnetizations (TRM). Because of the episodic nature of basaltic volcanism in this region, the 179 flows yielded only 65 time-distinct virtual geomagnetic poles (VGPs). The paleomagnetic pole calculated from the 65 cooling unit VGPs is located at 85.5{degree}N, 108.9{degree}E within a 4.4{degree} circle of 95% confidence. This pole is statistically indistinguishable (at 95% confidence) from reference poles calculated from rocks of similar age in stable North America and from a paleomagnetic pole calculated from rocks of similar age in Baja California. The coincidence of paleomagnetic poles from the Mojave-Sonora desert region with reference poles from the stable continental interior indicates that (1) significant vertical axis net tectonic rotations have not accompanied post-middle Miocene high-angle normal faulting in this region; (2) there has been no detectable post-middle Miocene latitudinal transport of the region; and (3) long-term nondipole components of the middle Miocene geomagnetic field probably were no larger than those of the recent (0-5 Ma) geomagnetic field. In contrast, paleomagnetic data indicate vertical axis rotations of similar age rocks in the Transverse Ranges, the Eastern Transverse Ranges, and the Mojave Block.

Calderone, G.J. (Geological Survey, Flagstaff, AZ (United States)); Butler, R.F.; Acton, G.D. (Univ. of Arizona, Tucson (United States))

1990-01-10

127

Constraints on Pleistocene pluvial climates through stable-isotope analysis of fossil-spring tufas and associated gastropods, Kharga Oasis, Egypt  

Microsoft Academic Search

Stable-isotope analyses of fossil-spring carbonates (tufas) and freshwater gastropods (Melanoides tuberculata) from the currently hyperarid Western Desert of Egypt indicate that this region received enough precipitation to support a small perennial lake during the height of the oxygen-isotope stage 6\\/5e pluvial event, and a substantial volume of spring discharge during prior pluvial phases. Tufa and gastropod oxygen-isotope ratios are generally

Jennifer R Smith; Robert Giegengack; Henry P Schwarcz

2004-01-01

128

Geomicrobiological Changes in Two Ephemeral Desert Playa Lakes in the Western United States  

Microsoft Academic Search

The geochemistry and microbiology of two ephemeral playa lakes in the Western United States, Surprise Valley Alkali Lake (SVAL) and Eldorado Playa (EP), were examined over one wetting cycle, revealing dramatic temporal changes in suspended mineralogy, aqueous chemistry, and bacterial populations. In SVAL the predominant suspended mineral changed from smectite to vermiculite and clinoptilolite, which led to a depletion of

Kyle C. Costa; Joy Hallmark; Jason B. Navarro; Brian P. Hedlund; Duane P. Moser; Stephanie Labahn; Debbie Soukup

2008-01-01

129

Movement of water through the thick unsaturated zone underlying Oro Grande and Sheep Creek Washes in the western Mojave Desert, USA  

Microsoft Academic Search

.   Previous studies indicate that a small quantity of recharge occurs from infiltration of streamflow in intermittent streams\\u000a in the upper Mojave River basin, in the western Mojave Desert, near Victorville, California. Chloride, tritium, and stable\\u000a isotope data collected in the unsaturated zone between 1994 and 1998 from boreholes drilled in Oro Grande and Sheep Creek\\u000a Washes indicate that infiltration

John A. Izbicki; John Radyk; Robert L. Michel

2002-01-01

130

Isolation and characterization of osmotolerant bacteria from thar desert of western Rajasthan (India).  

PubMed

The Thar Desert harsher environment harbors a limited diversity of life forms due to extreme conditions like low moisture of sandy soils and high soil temperature. In the present study, osmotolerant bacteria from the Thar soils were isolated and characterized. Bacteria were isolated from 20 soil samples (100 g), collected from sand dunes, suspended in water and absolute alcohol. A total of 11 biochemical and morphological tests were carried out for generic identification of bacteria. Osmotic tolerance capacity of isolates was examined on glycerol, NaCI and alcohol; and sequencing of 16S rRNA gene was also performed for bacterial identification. 16S to 23S rRNA internal transcribed spacer analysis (RISA) was done for phylogenetic analysis of isolates. The soil suspended in water contained 2.5 x 10(6) bacteria/g of soil while alcohol suspended soil had 4.4 x 10(4) bacteria/g. The 24 bacterial isolates were found tolerant to 26% glycerol, 14% NaCI and 10% of alcohol, and 22 out of 24 isolates were found Gram positive. The results showed that 45.83% and 41.67% bacteria belong to Bacillus spp. and Corynebacterium spp., respectively, while Acinetobacter spp., Aeromonas spp. and Staphylococcus spp. were in equal proportion (4.16% each). Six isolates were selected for 16S rRNA gene sequencing and five were found 95% similar with Bacillus licheniformis whereas one isolate was identified as B. subtilis. All the isolates showed good growth up to 50 degrees C with gradual reduction on subsequent increment of temperature. Out of 24 isolates, six could survive at 65 degrees C while one isolate could grow at 63 degrees C. Growth kinetic studies revealed that the reduction in generation time in solute(s) and temperature stress was more as compared to generation time in plain medium. This study suggests that virgin sand dunes may be a rich source of bacteria, tolerant to osmotrophic solutes, and can be examined for plant growth promotion activity in agriculture. Moreover, study might help to resolve the tactic adopted by microbes to defeat desiccation induced by various types of solutes. PMID:24432519

Sharma, Ramavtar; Manda, Rajni; Gupta, Shikha; Kumar, Sushil; Kumar, Vinod

2013-12-01

131

Three-dimensional structure of Conrad and Moho discontinuities in Egypt  

NASA Astrophysics Data System (ADS)

The three-dimensional structures of Conrad and Moho discontinuities beneath Egypt are investigated by local earthquake travel time inversion. A number of 2513 events with 24,696 arrival time data recorded by the Egyptian National Seismic Network (ENSN) are used. The station corrections of P- and S-waves and the hypocentral parameters are simultaneously estimated with the Conrad and Moho depths. The results of this study show that the discontinuities form patterns of shallow and deep structures getting shallow toward the northern and eastern coast, and deeper toward western Desert and northeastern Sinai. The Conrad and Moho discontinuities are located within the depth range 9-17 km and 27-41 km, respectively. The depth ranges of Conrad and Moho discontinuities are respectively: 15-16 km and 31-33 km in greater Cairo and Dahshour; 15-18 km and 32-35 km in Sinai; 16-17 and 33-35 km along the Nile River; 9 and 30 km near the Red Sea coast; 15 and 39 km toward the western desert. The comprehensive comparison with previous crustal studies suggests that the main patterns of Moho undulations and the range of Moho depths are in good agreement with the previous crustal models in Egypt, as well as with the Bouguer gravity anomalies that well explain the Nile River sediments, Red Sea mountain belts and Western Desert depression and Oasis. The model of the Moho and Conrad discontinuities improves knowledge of the three dimensional structure of the crust beneath Egypt in wide areas where geophysical data is sparse.

Abdelwahed, Mohamed F.; El-Khrepy, Sami; Qaddah, Atef

2013-09-01

132

Geochemical record of Late Quaternary paleoclimate from lacustrine sediments of paleo-lake San Felipe, western Sonora Desert, Mexico  

NASA Astrophysics Data System (ADS)

Stratigraphy, mineralogy, major and trace elements, organic carbon, carbonate, sulfate and AMS 14C dates are used to infer Late Quaternary depositional environments and paleo-hydrological conditions in the paleo-lake San Felipe located in the western part of Sonora Desert. Sediment stratigraphy divides the depth profile into aeolian and pluvio-lacustrine regimes. Aeolian regime is constrained to >44.5 14C kyr BP. The pluvio-lacustrine regime consists of two stratigraphic units with characteristic geochemical proxies indicating changing chemical weathering, clastic input, salinity and provenance and provides a measure of varying climatic conditions between ca. 37 and 3 14C kyr BP. Lower catchment erosion and inflow into the basin, higher lake productivity, precipitation of Na-sulfate mineral and higher clastic input from the proximal aeolian deposits during ca. 37-14 14C kyr BP are comparable to the regional registers of dominant winter rainfall related to westerly storm tracks and colder conditions. In the last 12 14C kyr BP, higher sedimentation and inflow and lower productivity are comparable to dominant summer rainfall. Higher humidity and lake productivity during ca. 37-29 14C kyr BP is possibly due to the position of westerly storm tracks at 31°N and the gradually reducing humidity till ca. 14 14C kyr BP is related to northerly migration of westerly storm tracks. Regional arid conditions during ca. 11 14C kyr BP and ca. 6 14C kyr BP are characterized by influx of coarser quartz and feldspars into the basin.

Roy, P. D.; Caballero, M.; Lozano, R.; Ortega, B.; Lozano, S.; Pi, T.; Israde, I.; Morton, O.

2010-04-01

133

Methanogens at the top of the world: occurrence and potential activity of methanogens in newly deglaciated soils in high-altitude cold deserts in the Western Himalayas.  

PubMed

Methanogens typically occur in reduced anoxic environments. However, in recent studies it has been shown that many aerated upland soils, including desert soils also host active methanogens. Here we show that soil samples from high-altitude cold deserts in the western Himalayas (Ladakh, India) produce CH4 after incubation as slurry under anoxic conditions at rates comparable to those of hot desert soils. Samples of matured soil from three different vegetation belts (arid, steppe, and subnival) were compared with younger soils originating from frontal and lateral moraines of receding glaciers. While methanogenic rates were higher in the samples from matured soils, CH4 was also produced in the samples from the recently deglaciated moraines. In both young and matured soils, those covered by a biological soil crust (biocrust) were more active than their bare counterparts. Isotopic analysis showed that in both cases CH4 was initially produced from H2/CO2 but later mostly from acetate. Analysis of the archaeal community in the in situ soil samples revealed a clear dominance of sequences related to Thaumarchaeota, while the methanogenic community comprised only a minor fraction of the archaeal community. Similar to other aerated soils, the methanogenic community was comprised almost solely of the genera Methanosarcina and Methanocella, and possibly also Methanobacterium in some cases. Nevertheless, ~10(3) gdw(-1) soil methanogens were already present in the young moraine soil together with cyanobacteria. Our results demonstrate that Methanosarcina and Methanocella not only tolerate atmospheric oxygen but are also able to survive in these harsh cold environments. Their occurrence in newly deglaciated soils shows that they are early colonizers of desert soils, similar to cyanobacteria, and may play a role in the development of desert biocrusts. PMID:24348469

Aschenbach, Katrin; Conrad, Ralf; Reháková, Klára; Doležal, Ji?í; Janatková, Kate?ina; Angel, Roey

2013-01-01

134

Methanogens at the top of the world: occurrence and potential activity of methanogens in newly deglaciated soils in high-altitude cold deserts in the Western Himalayas  

PubMed Central

Methanogens typically occur in reduced anoxic environments. However, in recent studies it has been shown that many aerated upland soils, including desert soils also host active methanogens. Here we show that soil samples from high-altitude cold deserts in the western Himalayas (Ladakh, India) produce CH4 after incubation as slurry under anoxic conditions at rates comparable to those of hot desert soils. Samples of matured soil from three different vegetation belts (arid, steppe, and subnival) were compared with younger soils originating from frontal and lateral moraines of receding glaciers. While methanogenic rates were higher in the samples from matured soils, CH4 was also produced in the samples from the recently deglaciated moraines. In both young and matured soils, those covered by a biological soil crust (biocrust) were more active than their bare counterparts. Isotopic analysis showed that in both cases CH4 was initially produced from H2/CO2 but later mostly from acetate. Analysis of the archaeal community in the in situ soil samples revealed a clear dominance of sequences related to Thaumarchaeota, while the methanogenic community comprised only a minor fraction of the archaeal community. Similar to other aerated soils, the methanogenic community was comprised almost solely of the genera Methanosarcina and Methanocella, and possibly also Methanobacterium in some cases. Nevertheless, ~103 gdw?1 soil methanogens were already present in the young moraine soil together with cyanobacteria. Our results demonstrate that Methanosarcina and Methanocella not only tolerate atmospheric oxygen but are also able to survive in these harsh cold environments. Their occurrence in newly deglaciated soils shows that they are early colonizers of desert soils, similar to cyanobacteria, and may play a role in the development of desert biocrusts.

Aschenbach, Katrin; Conrad, Ralf; Rehakova, Klara; Dolezal, Jiri; Janatkova, Katerina; Angel, Roey

2013-01-01

135

Phylogeny, divergence times and species limits of spiny lizards (Sceloporus magister species group) in western North American deserts and Baja California.  

PubMed

The broad distribution of the Sceloporus magister species group (squamata: phrynosomatidae) throughout western North America provides an appropriate model for testing biogeographical hypotheses explaining the timing and origins of diversity across mainland deserts and the Baja California Peninsula. We inferred concordant phylogenetic trees describing the higher-level relationships within the magister group using 1.6 kb of mitochondrial DNA (mtDNA) and 1.7 kb of nuclear DNA data. These data provide strong support for the parallel divergence of lineages endemic to the Baja California Peninsula (S. zosteromus and the orcutti complex) in the form of two sequential divergence events at the base of the magister group phylogeny. A relaxed phylogenetic analysis of the mtDNA data using one fossil and one biogeographical constraint provides a chronology of these divergence events and evidence that further diversification within the Baja California clades occurred simultaneously, although patterns of geographical variation and speciation between clades differ. We resolved four major phylogeographical clades within S. magister that (i) provide a novel phylogenetic placement of the Chihuahuan Desert populations sister to the Mojave Desert; (ii) illustrate a mixed history for the Colorado Plateau that includes Mojave and Sonoran Desert components; and (iii) identify an area of overlap between the Mojave and Sonoran Desert clades near Yuma, Arizona. Estimates of bidirectional migration rates among populations of S. magister using four nuclear loci support strong asymmetries in gene flow among the major mtDNA clades. Based on the nonexclusivity of mtDNA haplotypes, nuclear gene flow among populations and wide zones of phenotypic intergradation, S. magister appears to represent a single geographically variable and widespread species. PMID:17944851

Leaché, Adam D; Mulcahy, Daniel G

2007-12-01

136

M1A1 Abrams Tank in Egypt.  

National Technical Information Service (NTIS)

Egypt -- a land famous for its great Pyramids, the Sphinx, vast deserts, oases, the Nile River, and the best trained tank crews in the Arab world. The United States supports the Arab Republic of Egypt with financial aid and security assistance. One of the...

D. E. Sparrow T. O. Begasse

1994-01-01

137

The Badain Jaran desert: remote sensing investigations.  

USGS Publications Warehouse

Approximately half the Badain Jaran desert in the north-western Alashan Plain of northern China is a sand sea. The remainder is gravel or bedrock. The north-western border of the desert is a playa. The desert has been imaged by both Landsat and the Shuttle Imaging Radar (SIR-A). -from Authors

Walker, A. S.; Olsen, J. W.; Bagen

1987-01-01

138

Composition, age, and origin of the ~620 Ma Humr Akarim and Humrat Mukbid A-type granites: no evidence for pre-Neoproterozoic basement in the Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The Humr Akarim and Humrat Mukbid plutons, in the central Eastern Desert of Egypt, are late Neoproterozoic post-collisional alkaline A-type granites. Humr Akarim and Humrat Mukbid plutonic rocks consist of subsolvus alkali granites and a subordinate roof facies of albite granite, which hosts greisen and Sn-Mo-mineralized quartz veins; textural and field evidence strongly suggest the presence of late magmatic F-rich fluids. The granites are Si-alkali rich, Mg-Ca-Ti poor with high Rb/Sr (20-123), and low K/Rb (27-65). They are enriched in high field strength elements (e.g., Nb, Ta, Zr, Y, U, Th) and heavy rare earth elements (La n /Yb n = 0.27-0.95) and exhibit significant tetrad effects in REE patterns. These geochemical attributes indicate that granite trace element distribution was controlled by crystal fractionation as well as interaction with fluorine-rich magmatic fluids. U-Pb SHRIMP zircon dating indicates an age of ~630-620 Ma but with abundant evidence that zircons were affected by late corrosive fluids (e.g., discordance, high common Pb). ?Nd at 620 Ma ranges from +3.4 to +6.8 (mean = +5.0) for Humr Akarim granitic rocks and from +4.8 to +7.5 (mean = +5.8) for Humrat Mukbid granitic rocks. Some slightly older zircons (~740 Ma, 703 Ma) may have been inherited from older granites in the region. Our U-Pb zircon data and Nd isotope results indicate a juvenile magma source of Neoproterozoic age like that responsible for forming most other ANS crust and refute previous conclusions that pre-Neoproterozoic continental crust was involved in the generation of the studied granites.

Ali, Kamal A.; Moghazi, Abdel-Kader M.; Maurice, Ayman E.; Omar, Sayed A.; Wang, Qiang; Wilde, Simon A.; Moussa, Ewais M.; Manton, William I.; Stern, Robert J.

2012-10-01

139

Fractionation analysis of some heavy metals in sediments of the north-western part of the Red Sea, Egypt  

Microsoft Academic Search

Sequential extraction was used to study operationally determined chemical forms (exchangeable, carbonate, reducible metal, oxidisable metal and the residual fractions) of the metals Cd, Cu, Zn and Pb in sediments from 12 sample sites collected from the north-western part of the Red Sea, where improper recreational facilities have resulted in diverse impacts on the coastal environments fronting some of the

Hoda H. H. Ahdy; Doaa H. Youssef

2011-01-01

140

Sexual division of labor and central place foraging: a model for the Carson Desert of western Nevada  

Microsoft Academic Search

Archaeological models of hunter-gatherer subsistence often imply that the influence of men’s or women’s foraging effort on settlement patterns varied over time, but fail to consider how central place foraging may reflect conflicting subsistence interests between men and women. For example, earlier studies of Carson Desert prehistory suggest a semi-sedentary, gathering strategy replaced a mobile, hunting-oriented strategy in response to

David W Zeanah

2004-01-01

141

The Nile Delta, Egypt  

NASA Technical Reports Server (NTRS)

This pair of true- and false-color images from the Moderate Resolution Imaging Spectroradiometer was acquired on June 3, 2002. The fertile land along the Nile River supports lush green vegetation, amid the desert landscape. At its delta at the Mediterranean Sea, the Nile broadens into a large fan-shaped delta. All of Egypt's large cities fall along the Nile, which sustains life in a region of scant rainfall. At the point where the river widens into the delta, a grayish cluster of pixels marks the location of Cairo. To the east is the Sinai Peninsula, whose impermanent water courses create silvery streaks on the pale brown, arid landscape. At lower right is the Red Sea. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

2002-01-01

142

Preliminary Study of Babesia gibsoni Patton in Wild Carnivores and Domesticated Dogs in Egypt.  

National Technical Information Service (NTIS)

Three immature foxes, Vulpes vulpes niloticus (E. Geoffroy St. Hilaire), from the Mediterranean coastal desert near Burg El Arab, Egypt, were naturally infected by Babesia gibsoni Patton. Splenectomized jackals, Canis aureus lupaster (Hemprich and Ehrenbe...

R. R. Maronpot, E. Guindy

1969-01-01

143

76 FR 59682 - Desert Southwest Customer Service Region-Western Area Lower Colorado Balancing Authority-Rate...  

Federal Register 2010, 2011, 2012, 2013

...in effect. Regulation And Frequency Response Service Effective...Applicable Regulation and Frequency Response Service (Regulation...maintaining scheduled interconnection frequency at 60 cycles per second (60...lies with the Western Area Lower Colorado (WALC)...

2011-09-27

144

Military Review: Desert Shield/Desert Storm.  

National Technical Information Service (NTIS)

CONTENTS: CASCOM Support for DESERT SHIELD/DESERT STORM; Total Army CSS: Providing the Means for Victory; Logistics Automation Support for Desert Storm; Building the DESERT Logistics force; Depot operations Supporting DESERT SHIELD; The Readiness Group's ...

1991-01-01

145

Evolution of rattlesnakes (Viperidae; Crotalus) in the warm deserts of western North America shaped by Neogene vicariance and Quaternary climate change.  

PubMed

During Pleistocene, the Laurentide ice sheet rearranged and diversified biotic distributions in eastern North America, yet had minimal physical impact in western North America where lineage diversification is instead hypothesized to result from climatic changes. If Pleistocene climatic fluctuations impacted desert species, the latter would reflect patterns of restricted gene flow concomitant with indications of demographic bottlenecks. Accordingly, molecular evidence for refugia should be present within these distributions and for subsequent range expansions as conditions improved. We sought answers to these questions by evaluating mitochondrial DNA (mtDNA) sequences from four species of rattlesnakes [Crotalus mitchellii (speckled rattlesnake), Crotalus cerastes (sidewinder), Crotalus tigris (tiger rattlesnake), Crotalus ruber (red diamond rattlesnake)] with distributions restricted to desert regions of southwestern North America. We inferred relationships using parsimony and maximum likelihood, tested intraspecific clades for population expansions, applied an isolation-with-migration model to determine bi-directional migration rates (m) among regions, and inferred divergence times for species and clades by applying a semiparametric penalized likelihood approach to our molecular data. Evidence for significant range expansion was present in two of eight regions in two species (Crotalus mitchellii pyrrhus, C. tigris region north). Two species (C. cerastes, C. mitchellii) showed a distribution concomitant with northward displacement of Baja California from mainland México, followed by vicariant separation into subclades. Effects of Pleistocene climate fluctuations were found in the distributions of all four species. Three regional diversification patterns were identified: (i) shallow genetic diversity that resulted from Pleistocene climatic events (C. tigris, C. ruber); (ii) deep Pleistocene divisions indicating allopatric segregation of subclades within refugia (C. mitchellii, C. cerastes); and (iii) lineage diversifications that extended to Pliocene or Late Miocene (C. mitchellii, C. cerastes). Clade-diversifying and clade-constraining effects impacted the four species of rattlesnakes unequally. We found relatively high levels of molecular diversification in the two most broadly distributed species (C. mitchellii, C. cerastes), and lower levels of genetic diversification in the two species (C. tigris, C. ruber) whose ranges are relatively more restricted. Furthermore, in several cases, the distributions of subspecies were not congruent with our molecular information. We suggest regional conservation perspectives for southwestern deserts cannot rely upon subspecies as biodiversity surrogates, but must instead employ a molecular and deep historical perspective as a primary mechanism to frame biodiversity reserves within this region. PMID:16968275

Douglas, Michael E; Douglas, Marlis R; Schuett, Gordon W; Porras, Louis W

2006-10-01

146

Desert Features  

NSDL National Science Digital Library

Sand covers only about 20 percent of the Earth's deserts. Nearly 50 percent of desert surfaces are gravel plains where removal of fine-grained material by the wind has exposed loose gravel and occasional cobbles. This web page, produced by the U.S. Geological Survey, features text and photographs that describe desert landforms, soils, plants, and the role of water in the formation of desert landscapes.

147

AIRSAR Data for Geological and Geomorphological Mapping in the Great Sandy Desert and Pilbara Regions of Western Australia  

NASA Technical Reports Server (NTRS)

Enhancements of AIRSAR data have demonstrated the benefits of synthetic aperture radar (SAR) for revealing an additional and mich higher level of information about the composition of the terrain than enhancements f either SPOT-PAN or Landsat TM data. With appropriate image processing techniques, surface and near surface geological structures, hydrological systems (both current and ancient) and landform features, have been evidenced in a diverse range of landscapes. In the Great Sandy Desert region where spectral variability is minimal, radar's sensitivity to the micromorphology of sparse exposures of subcrop and lag gravels has provided a new insight into the region's geological framework, its landforms, and their evolution. In the Pilbara region, advanced processing of AIRSAR data to unmix the backscatter between and within the three frequencies of data has highlighted subsurface extensions of greenstone lithologies below sand cover and morphological evidence of past flow conditions under former climate regimes. On the basis of these observations, it is recommend that radar remote sensing technology involving the use of high resolution, polarimetric data be seriously considered as a viable tool for exploration in erosional and depositional environments located within Australia's mineral and oil-prospective provinces.

Tapley, Ian J.

1996-01-01

148

Eternal Egypt  

NSDL National Science Digital Library

Available in English, French, and Arabic, Eternal Egypt is a website with a wealth of information on "the artifacts, characters, and places that together comprise the wonder that is Eternal Egypt." The website is organized so visitors can choose between a guided tour, begin with one of the cultural highlights (such as The Temple of Luxor or Part of a Wall of a Tomb), or simply explore and discover. A key feature of the website is the context provided in relation to various topics, so that a visitor can learn about the artifacts, but also how they connect to other people, places and artifacts, and where they fit in terms of an overall timeline and on a multimedia map of Egypt. Topics include: Arts and Crafts (Libraries, Architecture, Paintings and Relief, Sculpture, Humanities, Crafts), Science (Archaeology, Mathematics, Astronomy, Medicine, Social Science, Engineering), Agriculture (Irrigation, Herding, Farming, Crops), Commerce and Trade (Transportation), Government (Leaders, Seats of Power, Theocracy, Military), and Society and Culture (Family, Food and Drinks, Clothing, Sports and Entertainment, Religion and Spirituality).

149

The surface pollen and relative pollen production of the desert vegetation of the Alashan Plateau, western Inner Mongolia  

Microsoft Academic Search

This preliminary investigation focuses on the comparison of the recent pollen precipitation and its related vegetation of\\u000a eight different plant communities in the Alashan Region, the most western part of the Inner Mongolia Autonomous Region. Most\\u000a zonal and azonal communities can be well identified by their pollen spectra. Relative pollen production factors of various\\u000a plant taxa have been calculated and

U. Herzschuh; H. Kürschner; Yuzhen Ma

2003-01-01

150

Data from a thick unsaturated zone underlying Oro Grande and Sheep Creek washes in the western part of the Mojave Desert, near Victorville, San Bernardino County, California  

USGS Publications Warehouse

This report presents data on the physical properties of unsaturated alluvial deposits and on the chemical and isotopic composition of soil water and soil gas collected at 12 monitoring sites in the western part of the Mojave Desert, near Victorville, California. Sites were installed using the ODEX air-hammer method. Seven sites were located in the active channels of Oro Grande and Sheep Creek Washes. The remaining five sites were located away from the active washes. Most sites were drilled to a depth of about 100 feet below land surface; two sites were drilled to the water table almost 650 feet below land surface. Drilling procedures, lithologic and geophysical data, and site construction and instrumentation are described. Core material was analyzed for water content, bulk density, water potential, particle size, and water retention. The chemical composition of leachate from almost 1,000 subsamples of cores and cuttings was determined. Water extracted from selected subsamples of cores was analyzed for tritium and the stable isotopes of oxygen and hydrogen. Water from suction-cup lysimeters and soil-gas samples also were analyzed for chemical and isotopic composition. In addition, data on the chemical and isotopic composition of bulk precipitation from five sites and on ground water from two water-table wells are reported.

Izbicki, John A.; Clark, Dennis A.; Pimental, Maria I.; Land, Michael T.; Radyk, John C.; Michel, Robert L.

2000-01-01

151

Economic analysis of water allocation policies regarding Nile River water in Egypt  

Microsoft Academic Search

The Government of Egypt is currently implementing projects that expand irrigated area on the Sinai Peninsula and in the southern desert. Those projects will reduce the supply of Nile River water available to farmers in the Nile Delta, which is a heavily populated and highly productive agricultural region. The southern desert project will obtain water directly from Lake Nasser, while

Dennis Wichelns

2002-01-01

152

Cultural Diversity or Cultural Imperialism: Liberal Education in Egypt.  

ERIC Educational Resources Information Center

A faculty member's experience at the American University in Cairo (Egypt) reveals that pluralism and tolerance are western concepts, even within the college curriculum. National identity affords cultural stability: where the American melting-pot experience is reinforced by the notion of cultural diversity, the national identity of Egypt is…

Blanks, David R.

1998-01-01

153

Molecular Epidemiological Study of Hepatitis Viruses in Ismailia, Egypt  

Microsoft Academic Search

The hepatitis virus is hyperendemic in Egypt, western Asia and Africa. In Egypt, most studies have been carried out in the regions of the upper and lower Nile Delta, and so little is known about other parts of the country. Our project aimed to clarify the carrier rate of various hepatitis viruses in the northeastern province of Ismailia. A total

Ahmed Youssef; Yoshihiko Yano; Takako Utsumi; Essam Mohamed Mohamed abd El-alah; Alaa El-een Saad abd El-Hameed; Adel El-Hamid Ahmed Serwah; Yoshitake Hayashi

2009-01-01

154

Nondestructive neutron activation analysis of some soil clays of Egypt  

Microsoft Academic Search

Fourteen clay samples separated from calcareous, lacustrine, Nile alluvium and desert alluvium soils of Egypt were analyzed by pure instrumental neutron activation analysis. Elemental composition was determined by high resolution gamma-spectrometry on samples irradiated with reactor neutrons using the monostrandard technique. This was carried out in the nuclear research center of Karlsruhe, West Germany. As many as 17 trace elements,

R. Zaghloul; S. El-Demerdashe; M. A. Abdel-Salam; E. A. Bakhoum

1987-01-01

155

Fairy, tadpole, and clam shrimps (Branchiopoda) in seasonally inundated clay pans in the western Mojave Desert and effect on primary producers  

PubMed Central

Background Fairy shrimps (Anostraca), tadpole shrimps (Notostraca), clam shrimps (Spinicaudata), algae (primarily filamentous blue-green algae [cyanobacteria]), and suspended organic particulates are dominant food web components of the seasonally inundated pans and playas of the western Mojave Desert in California. We examined the extent to which these branchiopods controlled algal abundance and species composition in clay pans between Rosamond and Rogers Dry Lakes. We surveyed branchiopods during the wet season to estimate abundances and then conducted a laboratory microcosm experiment, in which dried sediment containing cysts and the overlying algal crust were inundated and cultured. Microcosm trials were run with and without shrimps; each type of trial was run for two lengths of time: 30 and 60 days. We estimated the effect of shrimps on algae by measuring chlorophyll content and the relative abundance of algal species. Results We found two species of fairy shrimps (Branchinecta mackini and B. gigas), one tadpole shrimp (Lepidurus lemmoni), and a clam shrimp (Cyzicus setosa) in our wet-season field survey. We collected Branchinecta lindahli in a pilot study, but not subsequently. The dominant taxa were C. setosa and B. mackini, but abundances and species composition varied greatly among playas. The same species found in field surveys also occurred in the microcosm experiment. There were no significant differences as a function of experimental treatments for either chlorophyll content or algal species composition (Microcoleus vaginatus dominated all treatments). Conclusions The results suggest that there was no direct effect of shrimps on algae. Although the pans harbored an apparently high abundance of branchiopods, these animals had little role in regulating primary producers in this environment.

2010-01-01

156

Composition and antimicrobial activity of the essential oil of Heracleum thomsonii (Clarke) from the cold desert of the western Himalayas.  

PubMed

Volatile oil composition of hydro-distilled (HD) and supercritical carbon dioxide (SC-CO(2)) essential oil of freshly collected aerial parts of Heracleum thomsonii (Umbeliferae) from the western Himalayas was studied by GC-FID and GC-MS. Results revealed qualitative and quantitative dissimilarity in the composition of hydro-distilled and SC-CO(2) extracted oils. Nineteen constituents, which accounted for 89.32% of total constituents in HD oil, represented by limonene (4.31%), (Z)-?-ocimene (3.69%), terpinolene (22.24%), neryl acetate (36.19%), nerol (9.51%) and p-cymene-8-ol (2.61%) were identified. In SC-CO(2) extracted oil, 24 constituents representing 89.95% of total constituents were identified. Terpinolene (5.08%), germacrene D (2.17%), neryl acetate (51.62%), nerol (9.78%), geranyl acetate (2.06%), ?-bisabolol (2.48%) and 1-nonadecanol (4.96%) were the dominating constituents. In vitro antimicrobial activity of hydro-distilled oil was conducted against microrobial strains including two Gram-positive (Staphylococcus aureus and Bacillus subtilis) and five Gram-negative (Burkholderia cepacia, Escherichia coli, Enterobacter cloacae, Klebseilla pneumoniae and Pseudomonas aeruginosa) bacteria as well as seven fungi (Candida albicans, Issatchenkia orientalis, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Aspergillus sydowii and Trichophyton rubrum) using broth microdilution method. The results of bioassay showed that the oil exhibited moderate to high antimicrobial activity against fungi C. albicans (MIC 625 µg?ml(-1)), A. parasiticus (MIC 312.5 µg?ml(-1)), A. sydowii (MIC 312.5 µg?ml(-1)), T. rubrum (MIC 625 µg?ml(-1)), Gram-positive bacteria B. subtilis (MIC 625?µg?ml(-1)) and Gram-negative bacteria P. aeruginosa (MIC 312.5 µg?ml(-1)). PMID:21854172

Guleria, Shailja; Saini, Rikki; Jaitak, Vikas; Kaul, V K; Lal, Brij; Rahi, Praveen; Gulati, Arvind; Singh, Bikram

2011-08-01

157

Desert Sojourn.  

ERIC Educational Resources Information Center

Focuses on an activity in which the students in a beginning drawing class used middle-value brown paper and earthen shades of conte to draw pictures of bones in a desert environment. Discusses how the assignment teaches appreciation of the colors, sounds, and shapes of the desert. (CMK)

Greenman, Geri

1999-01-01

158

Hepatitis C antibody prevalence in blood donors in different governorates in Egypt.  

PubMed

Markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections were sought in serum samples from 2644 blood donors in 24 of Egypt's 26 governorates. Of the 2644 samples, 656 (24.8%) were shown to contain anti-HCV immunoglobulin G antibody by Abbott second generation enzyme immunoassays (EIA). Of 85 EIA-positive samples tested by recombinant immunoblot assay, 72 (85%) were positive. HCV seroprevalence in the governorates ranged from zero to 38%; 15 governorates (62%) had an HCV antibody prevalence greater than 20%, and 6 (25%) greater than 30%. Governorates with higher sero-prevalences were located in the central and north-eastern Nile river delta, and south of Cairo in the Nile river valley. Subjects from areas in and adjoining the Sinai peninsula, in the eastern and western desert, and in southernmost Egypt, had the lowest prevalence of HCV antibody. The large urban governorates of Cairo and Alexandria had antibody prevalences of 19% and 11%, respectively. A total of 39.4% subjects had evidence of HBV infection (and-HBV core antigen total antibody). HCV infections were detected more frequently in donors with markers for HBV infections than in uninfected subjects (36% versus 18%, P < 0.001). PMID:9231192

Arthur, R R; Hassan, N F; Abdallah, M Y; el-Sharkawy, M S; Saad, M D; Hackbart, B G; Imam, I Z

1997-01-01

159

Fracture types detected in eastern Mediterranean reservoirs (Turkey and Egypt)  

SciTech Connect

Most of Turkey's reservoirs are in the fractured Cretaceous Mardin Formation; however, new possibilities in fractured Paleozoic sandstones are being sought. The dominant fractures are fold related and are found on the northern flanks of the asymmetrical anticlines. The strike of these fractures is perpendicular to bedding planes and parallel to dip. There are fewer tear-fault-related and crestal-position fractures, but these may have a greater vertical extent. Fractures are present in all the producing areas of Egypt except the Nile delta. Basement fractures associated with shear zones in the southern Gulf of Suez have become an important exploration target. Fracture orientations are related to the major shear orientations except where later folding and faulting have caused structural rotation. The development of Zeit Bay field has shown that fractured basement rock can constitute a significant reservoir. The fracture reservoirs in northern Sinai and the Western Desert are in Cretaceous and Jurassic limestones and/or dolomitic limestones. The major shear fractures are parallel to the northwest-north-northwest compressive stresses that formed the reservoir structures; however, local fold- and fault-related fractures are also present.

Nurmi, R.; Taha, M. (Schlumberger, Dubai (United Arab Emirates )

1988-08-01

160

Desert Animals  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on adaptations that desert animals must make in order to survive in the harsh desert environment. Each student studies a certain creature and reports on specific adaptations it has made, and then a game is played to introduce students to these concepts. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

161

Desert Passage  

Microsoft Academic Search

T he First Movement of Steve Reich's The Desert Music begins with a pulse—rapid eighth notes that repeat over and over again—immediately cre- ating an energy that is kinetic. From the moment the first note is played, the listener is swept away, carried off into the distance by the relentless, beckon- ing quality of the music. The listener is eager

JONATHAN FRIEDMAN

162

Food Deserts  

Microsoft Academic Search

Food deserts and accessibility represent a new frontier in the assault of life-threatening, dietrelated diseases, including diabetes, obesity, hypertension, and atherosclerosis. Scholars represent the research literature from diverse disciplines, such as anthropology, agriculture, sociology, economics, marketing, public policy, sociology, and social epidemiology. Applied sociology has not contributed to this important conversation. Applied sociology's integration and use of theory, methods, and

Anthony Troy Adams; Monika J. Ulrich; Amanda Coleman

2010-01-01

163

Discovering Deserts.  

ERIC Educational Resources Information Center

Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Discovering Deserts." Contents are organized into the following sections: (1)…

Braus, Judy, Ed.

1985-01-01

164

Studies on the nutritional status of children aged 0–5 years in a drought-affected desert area of western Rajasthan, India  

Microsoft Academic Search

Objective: The present study was undertaken to assess the impact of drought on the nutritional status of pre-school children aged 0-5 years from a rural population in a desert area facing drought conditions very frequently. Design: The sampling design for assessment was the three-stage sampling technique. Setting: The study was carried out in 24 villages belonging to six tehsils (sub-units

Madhu B Singh; Ranjana Fotedar; J Lakshminarayana; PK Anand

2006-01-01

165

Nile behaviour and Upper Palaeolithic humans in Upper Egypt  

NASA Astrophysics Data System (ADS)

There is evidence of a decreasing human occupation of the Upper Egyptian Nile valley during the MIS 5 to MIS 3 period. Whereas very large extraction sites of the Middle Stone Age have been recorded, only very few sites of the Upper Palaeolithic have been found. The best explanation of this fact is that during the Late Middle Stone Age and the Upper Palaeolithc there was nearly no need for raw materials because there was only a very restricted population present in Upper Egypt. From about 22 ka BP an important population increase is registered by the presence of numerous Late Palaeolithic sites. During the whole LGM there is abundant presence of humans along the Nile Valley in Upper Egypt. This population was mainly living from fishing. There seems to be an abrupt end of the Palaeolithic occupation after 12.8 ka BP. Until now, no sites were found in the Valley until some rare Epipaleolithic sites occur about 8.0 ka BP. It will be suggested that these population changes are influenced by the river Nile behaviour. The best interpretation of the observations in the Upper Egyptian Nile Valley is the hypothesis that at the same time that Nile flow was reduced because of the dryness in its source area, the impact of aeolian activity was increased over Northeast Africa. The increased aeolian activity by northern winds in the Fayum and Wadi Ryan during the LGM resulted in the accumulation of aeolian sand in the valley. That aeolian sand was transported along the western Nile valley cliffs until it was accumulated when the Nile Valley change it S-N direction, such as at Nag'Hammadi. At other places sand was invading the Nile valley, directly from the Western Desert, creating a damming of the Nile at several places such as Armant and Aswan. As Nile flow was quite reduced, the Nile was unable to erode all the incoming sand and the Nile water with its important clay content was dammed. At several places large lakes were created in the Nile Valley. Those lakes were an ideal place for the settlement of the Late Palaeolithic fishers. There came an abrupt end to this situation when the Nile returned to its meandering regime at the end of the LGM. This situation created an catastrophic food crisis for the

Vermeersch, Pierre M.

2014-05-01

166

Desert USA: Desert Animals and Wildlife  

NSDL National Science Digital Library

This great educational website about Desert Animals and Wildlife was created by DesertUSA, a publication designed to explore and educate about "the beauty, life, and culture of North American deserts." The Desert Animals and Wildlife homepage contains extensive lists of links to sites for different Mammals, Birds and Fish, Reptiles and Amphibians, and Insects and Spiders. The animal link selections include the Mexican Gray Wolf, Desert Pupfish, Desert Iguana, and Finback Whale just to name a few. The specific animal pages include photos and information categorized in areas such as Distribution, Habitat, Description, and Life Cycle. There is a feature link to a webpage on Desert Animal Survival, a list of links to relevant DesertUSA Articles and Information, and links to websites dedicated to other DesertUSA subjects such as Plants / Wildflowers, and Peoples and Cultures.

167

Desert Dwellers  

NSDL National Science Digital Library

This lesson plan is part of the discoveryschool.com lesson plan library for grades 9-12. This lesson focuses on desert ecology, geography, and development, with an emphasis on desertification and what can be done to prevent it. It includes objectives, materials, procedures, discussion questions, evaluation ideas, performing extensions, suggested readings, and vocabulary. There are videos available to order which complement this lesson, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

168

Diet and cooking practices in Egypt: Exploration of potential relationship to early-onset colorectal cancer  

Microsoft Academic Search

Colorectal cancer in the seventh most common cancer in Egypt. However, the proportion of persons under age 40 who have colorectal cancer is 5 to 6 times that of western countries. High fiber and low fat intake represented by a high-vegetable, low meat diet is characteristic of other age groups in Egypt. The objective of this study was to describe

Amr S. Soliman; Ahmed Khorshid; Nabih Ibrahim; Laila Dorgham; R. Sue McPherson

1998-01-01

169

Deserts: Geology and Resources  

NSDL National Science Digital Library

This book provides an introduction to processes and features of the desert environment. Topics include how a desert is defined, how atmospheric conditions influence aridity, and the location and distribution of the world's deserts. There is also discussion of types of deserts, desert features, dunes, and eolian processes (the action of wind). Other topics include the use of remote sensing in studying deserts, mineral deposits, and the process of desertification.

170

The major element chemistry of Libyan desert glass and the mineralogy of its precursor  

NASA Astrophysics Data System (ADS)

Chemical analyses of four specimens of Libyan desert glass, a natural, high-silica glass believed to have formed as the result of a hypervelocity meteorite impact on the western desert of Egypt, are presented. Bulk analyses of specimens chosen to represent the color range of the glass exhibit very narrow chemical ranges for SiO2 (97.38-98.25 wt %), Al2O3 (1.16-2.26 wt %), total Fe (0.15-0.60 wt % as Fe2O3) and TiO2 (0.13-0.19 wt %), with measurable MgO found in only one specimen. Microprobe analyses show that Al, Fe and Ti are all positively correlated with one another and are almost ubiquitously distributed throughout the glass, while Mg is sharply limited in appearance and correlates only with Fe. Results indicate that the parent material was a sand or sandstone composed of quartz grains coated with a mixture of kaolinite, hematite and anatase. It is pointed out, however, that chemical comparisons may not prove sufficient to identify the presently unknown parent crater.

Fudali, R. F.

1981-09-01

171

Geochemical and hydrological processes controlling groundwater quality in Assiut Governorate, Egypt  

NASA Astrophysics Data System (ADS)

Groundwater in Assiut area, Egypt, is an important source of fresh water for human consumption, agriculture, and domestic and industrial purposes. Due to a growing population and expansion of agricultural reclamation projects in the desert fringes of the Nile Valley, there is an increasing water demand in this arid region. This study has investigated the geochemical and hydrological processes that control groundwater quality within the Pleistocene, Plio-Pleistocene, and Eocene aquifers in Assiut, in addition to the hydraulic relationships between surface and groundwater systems and the relations among the defined groundwater aquifers. A total of 28 surface and 160 groundwater samples were collected for geochemical analysis (major and minor element chemistry, and stable isotope analyses). Total dissolved solids = 182 to 5657 mg/L, water-delta 18O = -7.5 to +6.5%, and water-delta D = -55 to +32%. Geochemical and stable isotope data indicate that the principal source of recharge to the Pleistocene and Plio-Pleistocene aquifers is the surface water system (irrigation canals), while the prevalence of Na-Cl type waters in the Eocene aquifer indicates recharge by upward leakage from the underlying Nubian sandstone aquifer which contains the same Na-Cl water type. Evaporation prior to infiltration, mixing, and mineral equilibria (dissolution and precipitation) are the main factors that affect water quality. Ion exchange plays a secondary role in controlling the water chemistry of the Pleistocene aquifer, but is more effective in controlling water quality within the Plio-Pleistocene and Eocene aquifers due to the prevalence of clay minerals within the matrices. The fresh water exploited from the Eocene aquifer may be of great importance for land reclamation projects not only at the western desert fringes, but also at the eastern desert fringes of Assiut and similar settings around the River Nile south of Assiut Governorate. Results of this study will be helpful for sustainable development, and raising the standard of living of people in the Assiut area, which is one of the poorest regions of Egypt.

Mohammad, R. G.; Tempel, R.; Gomaa, M.; Korany, E.

2011-12-01

172

Geology and origin of Meatiq Dome, Egypt: A Precambrian metamorphic core complex?  

Microsoft Academic Search

Meatiq Dome, a metamorphic complex in the Precambrian basement of the Eastern Desert of Egypt, exhibits many of the essential features of Cordilleran metamorphic core complexes. It is an antiformal structure with low-dipping foliation and unidirectional mineral-slickenside lineation. The core consists of granite gneiss and is conformably overlain by a heterogeneous, isoclinally folded, mylonitic carapace. The carapace grades upward into

Neil C. Sturchio; Mohamed Sultan; Rodey Batiza

1983-01-01

173

Desert USA: Desert Plants and Wildflowers  

NSDL National Science Digital Library

Desert plants have adapted to the extremes of heat and aridity by using both physical and behavioral mechanisms, much like desert animals. The ingenuity and variety of these many adaptations are explored in a set of links to wildflowers, cacti and succulents, trees, shrubs, and grasses. Links to related topics such as desert plant survival, wildflower articles, and others are also included.

2000-01-01

174

Phytomonitoring the unique colonization of oil-contaminated saline environment by Limoniastrum monopetalum (L.) Boiss in Egypt.  

PubMed

A site that covers over 20 acres of coastal saline depression in the western Mediterranean coastal desert of Egypt (El-Hammra station, the main crude oil pipeline terminal in Al-Alamein) is contaminated with crude oil spill as a result of activities from refineries, oilfield blowouts, tanker and pipeline break-ups. This area, prior to contamination, was dominated by different common halophytes. However, Limoniastrum monopetalum is now the only species found growing in the oil-contaminated soil. A specific question addressed in the present study was: what are the biochemical changes occurring in a desert plant growing in oil-contaminated soils? Major metabolites such as proline, betaine, free amino acids, fatty acid esters and mineral elements were studied. The plant samples were collected from the oil-contaminated, as well as noncontaminated, sites. The higher concentration in the selected organic metabolites in the plants growing in the contaminated site compared to those in noncontaminated site may be due to differences in a number of receptors. The sensitivity of such receptors for the environmental signal that cause differences in genetic expression leads to differences in physiological processes. The change in the landscape of the contaminated area and the elimination of the natural vegetation, except L. monopetalum, may explain the competitive balance toward the oil-resistant species. PMID:12046949

Hussein, Hussein S; Terry, Norman

2002-04-01

175

The Cretaceous glauconitic sandstones of Abu Tartur, Egypt  

NASA Astrophysics Data System (ADS)

The Abu Tartur mine is located in the Western Desert of Egypt, 50 km west of El Kharga City. Geologically, the Abu Tartur plateau is built by a sequence of Upper Cretaceous (Campanian - Maastrichtian) phosphorites, black shales and glauconitic sandstones. The phosphate deposits are of great economic importance and have been mined since their discovery in 1967. Outcrop sections were measured, sampled, sedimentologically characterized and described. One specific glaucony layer was investigated mineralogically and chemically in detail and compared to a subsurface sample from the mine. Two depositional regimes can be interpreted based on sedimentary architecture and structures: 1) a deeper-water hemipelagic environment, where phosphorites and organic carbon-rich shales were deposited and 2) a shallower, prograding higher energy shelf environment with glauconies. From a sequence stratigraphic perspective 1) was deposited during the transgressive systems tract and the early highstand while 2) was deposited during the remaining highstand and a lowstand prograding wedge (Glenn & Arthur, 1990). Petrographic and SEM investigations show that the glaucony grains are of authochtonous origin. XRF, EMPA and thin-section analyses show that the glaucony grains from the outcrop differ significantly in their chemical composition, morphology and color from the grains of the mine sample. The fresh glauconies are enriched in Fe2O3 and K2O compared to the surface samples. XRD analyses of the clay fraction of the six outcrop samples and the mine sample show that the grains consist of illite(glauconite)/smectite mixed-layers, with more illite layers (80 %) in the mine sample. The charge distribution diagram muscovite-pyrophyllite-celadonite shows a clear trend from smectitic glaucony to illitic glaucony, the mine sample plots exactly in the field for glauconites. All these features indicate that the surface samples are strongly altered by weathering and that glauconite progressively transforms into iron-rich illte/smectite mixed layers and then into smectites. For any chemical and mineralogical characterization of glauconites at surface, these weathering effects have to be taken into consideration. GLENN, C. R. & ARTHUR, M. A. (1990): Anatomy and origin of a Cretaceous phosphorites-greensand giant, Egypt. Sedimentology, 37, 123-154.

Pestitschek, Brigitte; Gier, Susanne; Essa, Mahmoud; Kurzweil, Johannes

2010-05-01

176

Amphibian Declines and Environmental Change in the Eastern Mojave Desert  

Microsoft Academic Search

Eight amphibian taxa historically inhabited sparsely distributed wetlands in the Mojave Desert of western North America, habitats that have been dramatically altered or eliminated as a result of human activities. Changes in the distributions of these and two introduced amphibians, and associated environmental changes, are evaluated herein for an approximately 20,000 km2 area in the eastern Mojave Desert. Striking changes

David F. Bradford

177

Desert Dust Air Mass Mapping in the Western Sahara, using Particle Properties Derived from Space-based Multi-angle Imaging  

NASA Technical Reports Server (NTRS)

Coincident observations made over the Moroccan desert during the SAhara Mineral dUst experiMent (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from Multi-angle Imaging SpectroRadiometer (MISR) observations, and to place the sub-orbital aerosol measurements into the satellite's larger regional context. On three moderately dusty days for which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 to 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR's ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape, and single-scattering albedo. For the three study days, the satellite observations (a) highlight regional gradients in the mix of dust and background spherical particles, (b) identify a dust plume most likely part of a density flow, and (c) show an air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometers away.

Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Fiebig, Marcus; Schladitz, Alexander; von Hoyningen-Huene, Wolfgang

2008-01-01

178

Desert Dust Aerosol Air Mass Mapping in the Western Sahara, Using Particle Properties Derived from Space-Based Multi-Angle Imaging  

NASA Technical Reports Server (NTRS)

Coincident observations made over the Moroccan desert during the Sahara mineral dust experiment (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from multi-angle imaging spectroradiometer (MISR) observations, and to place the suborbital aerosol measurements into the satellite s larger regional context. On three moderately dusty days during which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR s ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape and single-scattering albedo. For the three study days, the satellite observations (1) highlight regional gradients in the mix of dust and background spherical particles, (2) identify a dust plume most likely part of a density flow and (3) show an aerosol air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometres away.

Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Esselborn, Michael; Fiebig, Marcus; Heese, Birgit; Knippertz, Peter; Mueller, Detlef; Schladitz, Alexander; Von Hoyningen-Huene, Wolfgang

2008-01-01

179

Storage Temperature of Explosive Hazard Magazines. Part I. American Desert.  

National Technical Information Service (NTIS)

Temperature measurements (162,000 data points) from the 'explosive hazard magazines' in the desert regions of the Western United States at Yuma, Arizona, China Lake, California, and Hawthorne, Nevada, were assessed for the purpose of establishing temperat...

I. S. Kurotori H. Schafer

1966-01-01

180

Desert Voices: Southwestern Children's Literature.  

ERIC Educational Resources Information Center

Examines three books with different ways of writing about the desert. Discusses: "Here Is the Southwestern Desert" by Madeline Dunphy, "The Desert Is My Mother" by Pat Mora, and "The Desert Mermaid" by Alberto Blanco. (PA)

Polette, Keith

1997-01-01

181

Data from a Thick Unsaturated Zone Underlying Two Artificial Recharge Sites along Oro Grande Wash in the Western Part of the Mojave Desert, near Victorville, San Bernardino County, California, 2001-2006  

USGS Publications Warehouse

This report presents data on the physical and hydraulic properties of unsaturated alluvial deposits and on the chemical and isotopic composition of water collected at two recharge sites in the western part of the Mojave Desert, near Victorville, California, from 2001 to 2006. Unsaturated-zone monitoring sites were installed adjacent to the two recharge ponds using the ODEX air-hammer and air rotary method to depths of about 460 feet and 269 feet below land surface. Each of the two unsaturated-zone monitoring sites included a water-table well, matric-potential sensors, and suction-cup lysimeters installed in a single bore hole. Drilling procedures, lithologic and geophysical data, and site construction and instrumentation are described. Core material was analyzed for water content, bulk density, water potential, particle size, and water retention. The chemical composition of leachate from almost 400 samples of cores and cuttings was determined. Water from suction-cup lysimeters also was analyzed for chemical and isotopic composition. In addition, data on the chemical and isotopic composition of groundwater from the two water-table wells are reported along with chemical and isotopic composition of the surface water in the recharge ponds.

Clark, Dennis A.; Izbicki, John A.; Johnson, Russell D.; Land, Michael T.

2009-01-01

182

Dwarfs in ancient Egypt.  

PubMed

Ancient Egypt was one of the most advanced and productive civilizations in antiquity, spanning 3000 years before the "Christian" era. Ancient Egyptians built colossal temples and magnificent tombs to honor their gods and religious leaders. Their hieroglyphic language, system of organization, and recording of events give contemporary researchers insights into their daily activities. Based on the record left by their art, the ancient Egyptians documented the presence of dwarfs in almost every facet of life. Due to the hot dry climate and natural and artificial mummification, Egypt is a major source of information on achondroplasia in the old world. The remains of dwarfs are abundant and include complete and partial skeletons. Dwarfs were employed as personal attendants, animal tenders, jewelers, and entertainers. Several high-ranking dwarfs especially from the Old Kingdom (2700-2190 BCE) achieved important status and had lavish burial places close to the pyramids. Their costly tombs in the royal cemeteries and the inscriptions on their statutes indicate their high-ranking position in Egyptian society and their close relation to the king. Some of them were Seneb, Pereniankh, Khnumhotpe, and Djeder. There were at least two dwarf gods, Ptah and Bes. The god Ptah was associated with regeneration and rejuvenation. The god Bes was a protector of sexuality, childbirth, women, and children. He was a favored deity particularly during the Greco-Roman period. His temple was recently excavated in the Baharia oasis in the middle of Egypt. The burial sites and artistic sources provide glimpses of the positions of dwarfs in daily life in ancient Egypt. Dwarfs were accepted in ancient Egypt; their recorded daily activities suggest assimilation into daily life, and their disorder was not shown as a physical handicap. Wisdom writings and moral teachings in ancient Egypt commanded respect for dwarfs and other individuals with disabilities. PMID:16380966

Kozma, Chahira

2006-02-15

183

Nile Delta, Egypt  

NASA Technical Reports Server (NTRS)

The Nile Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population of 57 million. The capital city of Cairo is at the apex of the delta in the middle of the scene. Across the river from Cairo can be seen the three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

1982-01-01

184

Nubian Complex strategies in the Egyptian high desert.  

PubMed

Systematic survey by the Abydos Survey for Paleolithic Sites project has recorded Nubian Complex artifact density, distribution, typology, and technology across the high desert landscape west of the Nile Valley in Middle Egypt. Our work contrasts with previous investigations of Nubian Complex settlement systems in Egypt, which focused on a small number of sites in the terraces of the Nile Valley, the desert oases, and the Red Sea Mountains. Earlier research interpreted the Nubian Complex, in particular, as a radiating settlement system that incorporated a specialized point production. Our high desert data, however, indicate that the Nubian Complex associated with early modern humans in this region of the high desert reflects a circulating, rather than a radiating, settlement system, and that point production has been over-emphasized. Data available from our work, as well as sites investigated by others, do not conclusively identify Nubian Complex behavioral strategies as modern. These data, however, do contribute to the understanding of landscape use by early modern human populations living along the Nile Valley Corridor route out of Africa. PMID:20659756

Olszewski, Deborah I; Dibble, Harold L; McPherron, Shannon P; Schurmans, Utsav A; Chiotti, Laurent; Smith, Jennifer R

2010-08-01

185

Recent environmental change and prehistoric human activity in Egypt and Northern Sudan  

NASA Astrophysics Data System (ADS)

This paper reviews the various Late Quaternary records that are available from western Egypt and northern Sudan, which includes more than 500 published radiocarbon dates and various sedimentary archives from local landscape components, including palaeolakes, soils, drainages (wadis), and archaeological sites. This palaeoenvironmental compilation frames the spatial and temporal context of local cultural activities when the region was most hospitable ˜9000-6000 BP; at this time, monsoonal weather influenced the portion of the African continental interior, creating enough convective rainfall for occasional surface water storage. In this part of the modern Sahara, rapid hydroclimatic changes play a key role in geomorphic evolution and resource availability. As 'watering holes' formed and dried up in the Early to Middle Holocene, Neolithic people developed various subsistence strategies, including opportunistic hunting of small animals (e.g. gazelle and hare), and food-related (e.g. wild sorghum, millet, and legumes) activities: gathering, plant cultivation and livestock-rearing. During its wettest phases during the 'monsoonal maximum,' the area was drought-prone, sustaining a meager steppe-shrub desert flora. Further desertification and aeolian deflation during the Middle and Late Holocene fostered technological innovation, migration and settlement, as well as the further development of agrarian communities and complex culture.

Nicoll, Kathleen

2004-03-01

186

Reflections about bizarre mummification practices on mummies at Egypt's Dakhleh oasis: a review.  

PubMed

About 100 mummified human remains were excavated from the Dakhleh Oasis in Egypt's Western Desert. Of these, less than half were examined by dissection. These dated to the Late Ptolemaic and Roman Periods. Initially, a confusing pattern of mortuary mummification practices was encountered that was identified ultimately as a product of primarily initial spontaneous mummification by desiccation. This was followed by tomb robbing in antiquity with unwrapping; body disarticulation followed, in turn, by mummy body reconstruction with atypical use of resin applications. Some of the resin was shown to be contaminated by bitumen that was responsible for inappropriately old radiocarbon dates of mummy tissue samples. Chemical reconstruction of diet using stable isotope ratios of carbon and nitrogen characterized their diet to be primarily that of C3 plants, consistent with trading records excavated from that site. Analysis of the mummy coprolites also enabled the first finding of the intestinal parasite Enterobius vermicularis in either ancient or modern Egyptian human coprolites. The principal focus of this report is to demonstrate and verify the value of including visceral dissection as part of a mummy examination whenever possible. PMID:20440958

Aufderheide, Arthur C

2009-12-01

187

Himalayan Mountain Range, Taklimakan Desert, China  

NASA Technical Reports Server (NTRS)

Looking north from Kashmir India (27.5N, 76.5E) into the Tibetan Plateau and beyond, the Taklimakan Desert of far western China appears to be covered with an extensive layer of haze that blankets the entire region. Reaching even into the western Siberian Plains of the CIS. This rugged land is one of the world's richest treasure troves of mineral wealth but the accessability into this remote area is so difficult that it is not yet economically feasible.

1991-01-01

188

Environmental health in Egypt  

Microsoft Academic Search

Egypt shares most of the environmental problems of developing countries. One of the most important health and environmental problems is air pollution resulting from using fuel, burning operations, and the increase of automobile exhaust in cities. Moreover, the deficiency of efficient sanitation services and water pollution caused by the breaking down of old and consumed water networks, as well as

Wagida A. Anwar

2003-01-01

189

Where Deserts Form  

NSDL National Science Digital Library

Most of Earth's deserts can be found in dry areas created by global circulation patterns. The deserts of our world are not restricted by latitude, longitude, or elevation. This site, produced by the U.S. Geological Survey, uses text and pictures to describe how atmospheric circulation patterns influence the locations of deserts on Earth and possibly on other terrestrial planets as well.

190

Operation Desert Shield and Desert Storm.  

National Technical Information Service (NTIS)

So what did you do in the War, Daddy. As a Battalion Commander of an AH-64 Attack Helicopter Battalion during Operations Desert Shield and Desert Storm, my experiences were many, my memories everlasting. Rather than enumerate a chronology of events, I wil...

A. R. Jones

1992-01-01

191

The status of agricultural lands in Egypt: The use of multitemporal NDVI features derived from landsat TM  

Microsoft Academic Search

Agricultural production in Egypt is limited by soil salinity and by the encroachment of urban settlements onto previously cultivated lands. In contrast, reclamation efforts in the desert and coastal areas increase the amount of land cultivated. In this study, field-calibrated, multi-temporal NDVI features derived from 10 Landsat TM images dating from 1984 to 1993 were used to assess the status

Mary Pax Lenney; Curtis E. Woodcock; John B. Collins; Hassan Hamdi

1996-01-01

192

Egypt Service Provision Assessment Survey, 2002.  

National Technical Information Service (NTIS)

The 2002 Egypt Service Provision Assessment Survey (ESPA) was designed to collect information on the provision of reproductive health and child health services in Egypt in order to complement the information obtained through the 2000 Egypt Demographic and...

2003-01-01

193

Eutrophication Problem in Egypt  

Microsoft Academic Search

\\u000a The coastal area of Egypt on the Mediterranean Sea extends for about 1,200 km. It hosts a number of important residential\\u000a and economic centres, like the cities of Alexandria, Port Said, Damietta, Rosetta, Matruh, and AL-Arish. The coastal strip\\u000a between Alexandria and Matruh hosts tens of tourist villages, which are usually crowded by visitors during summer. Many activities\\u000a are known in

Mohamed M. Dorgham

194

Female desert bighorn sheep in the Sonora desert  

NSDL National Science Digital Library

Desert bighorn sheep use a lot of energy to regulate their internal temperature in the desert. During the summer the sheep eat plants and drink water every few days. In the winter, desert plants contain enough water for sheep survival.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-13

195

New paleocene sepiid coleoids (cephalopoda) from Egypt: evolutionary significance and origin of the sepiid 'rostrum'.  

PubMed

New coleoid cephalopods, assignable to the order Sepiida, are recorded from the Selandian/Thanetian boundary interval (Middle to Upper Paleocene transition, c. 59.2 Ma) along the southeastern margin (Toshka Lakes) of the Western Desert in Egypt. The two genera recognised, Aegyptosaepia n. gen. and ?Anomalosaepia Weaver and Ciampaglio, are placed in the families Belosaepiidae and ?Anomalosaepiidae, respectively. They constitute the oldest record to date of sepiids with a 'rostrum-like' prong. In addition, a third, generically and specifically indeterminate coleoid is represented by a single rostrum-like find. The taxonomic assignment of the material is based on apical parts (as preserved), i.e., guard, apical prong (or 'rostrum-like' structure), phragmocone and (remains of) protoconch, plus shell mineralogy. We here confirm the shell of early sepiids to have been bimineralic, i.e., composed of both calcite and aragonite. Aegyptosaepia lugeri n. gen., n. sp. reveals some similarities to later species of Belosaepia, in particular the possession of a distinct prong. General features of the phragmocone and protoconch of the new form are similar to both Belocurta (Middle Danian [Lower Paleocene]) and Belosaepia (Eocene). However, breviconic coiling and the presence of a longer ventral conotheca indicate closer ties with late Maastrichtian-Middle Danian Ceratisepia. In this respect, Aegyptosaepia n. gen. constitutes a link between Ceratisepia and the Eocene Belosaepia. The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin of belosaepiids, during the early to Middle Paleocene. These earliest known belosaepiids may have originated in the Tethyan Realm. From northeast Africa, they subsequently spread to western India, the Arabian Plate and, probably via the Mediterranean region, to Europe and North America. PMID:24348918

Koš?ák, Martin; Jagt, John W M; Speijer, Robert P; Stassen, Peter; Steurbaut, Etienne

2013-01-01

196

Modern Egypt: A Development Perspective.  

ERIC Educational Resources Information Center

Egypt is a culture which combines the traditional with the modern. This text aims to foster an appreciation of Egypt as a changing culture facing the challenges of development. Topics included are: (1) Village Life; (2) Urban Life; (3) Nile; (4) Government; (5) Agriculture; (6) Economy; (7) Health/Games; (8) Education; (9) Religion; (10)…

Scott, Rosalind; And Others

197

What's It Like Where You Live? Desert  

NSDL National Science Digital Library

This site provides excellent background information on deserts. Large print and superb pictures make this site very appealing to younger students. Topics include: What is a Desert Like?, Types of Deserts, What causes Deserts?, Deserts of the World, Desert Plants, Desert Animals, and links to other desert sites.

2002-01-01

198

Atacama Desert Soil Microbiology  

Microsoft Academic Search

The Atacama Desert is an ancient temperate desert (mean annual temperature of 14–16°C) that extends across 1,000 km from 30°S\\u000a to 20°S along the Pacific coast of South America (McKay et al. 2003; Fig. 6.1). As discussed by Rundel et al. (1991) and Miller\\u000a (1976) the desert owes its extreme aridity to the climatic regime dominated by a constant temperature

Benito Gómez-Silva; Fred A. Rainey; Kimberley A. Warren-Rhodes; Christopher P. McKay; Rafael Navarro-González

199

Desert Water Keepers  

NSDL National Science Digital Library

In this outdoor, sunny day activity, learners experiment with paper leaf models to discover how some desert plants conserve water. Learners explore adaptations of various desert plants such as waxy coatings, thick stems, and spines and fine hairs to see which characteristics best help a plant hold water. Learners compare their model leaves to real desert leaves if they are available. Even in a nondesert region, the activity can be done at a local botanical garden that may include a desert plant collection or in any hot, dry area.

Science, Lawrence H.

1980-01-01

200

Why Are Deserts Dry?  

NSDL National Science Digital Library

The deserts of the world today are not the deserts of the planet's past. Fossilized hippopotamus and elephant bones tell us that the Sahara, for instance, was a much moister and more hospitable environment 8,000 years ago than it is now. Each of the Earth's modern deserts are a consequence of one of the following mechanisms: air mass subsidence, rain shadows, distant moisture sources, or cold offshore temperatures at the sea's surface. This site uses text and scientific illustrations to describe how each of these mechanisms results in the occurrence of deserts.

201

Egypt at the crossroads.  

PubMed

Egypt is the location of the 1994 International Population and Development Conference. Conditions in Egypt due to expected population growth rates are anticipated as headed for "ecological breakdown." There is loss of prime agricultural land to urban expansion and difficulties in providing employment and vital services. The fertility decline to 4 children/family is still inadequate to meet resource needs; a 2-child family norm must be adopted because the country can barely meet the needs of 90 million people. Cairo is becoming a mega-city of squatter settlements and slums. Population densities approach 140,000/sq. kilometers. The family planning (FP) program receives top political support. The contraceptive prevalence rate has risen to just over 50%, a 10% increase since 1988. Egypt is the first Muslim country to surpass the 50% mark. Credit for this accomplishment is given to public information and education campaigns to reduce family size, expansion of maternal and child health services and FP, the cooperation of Muslim clerics, and better educated women. Nongovernmental organizations have played an active role in FP. The future challenge is to improve services and outreach and keep up with demand. Attitudes in rural areas have changed, so that desiring children to help with farm work is the exception. Progress on arresting environmental destruction has not been as successful. There are still poor irrigation practices. The breadbasket the Nile River sustained no longer exists; Egypt is a net importer of food. Water shortages and water quality limit productivity. 57.2 billion cu. meters out of 58.4 billion cu. meters of freshwater available from the Nile River are used primarily for irrigation of the 17.6 million hectares of agricultural land along the river and its delta. Salts have polluted the river from fertilizers and pesticides and municipal and industrial wastes. Industrial dumping is illegal, but continues. Treatment plants are inadequate and water pipes are in need of repair. In order to meet water needs in the year 2000, irrigation water needs to be reclaimed. There is a race against time toe correct mismanagement. PMID:12344703

Hinrichsen, D

1992-01-01

202

Deserts and Wind  

NSDL National Science Digital Library

This site contains 20 questions on the topic of deserts and wind, which covers dunes, desert location and formation, and particle transportation. This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate feedback.

Heaton, Timothy

203

Integrated geoelectrical survey for groundwater and shallow subsurface evaluation: case study at Siliyin spring, El-Fayoum, Egypt  

NASA Astrophysics Data System (ADS)

Siliyin spring is one of the many natural fresh water springs in the Western Desert of Egypt. It is located at the central part of El-Fayoum Delta, which is a potential place for urban developments and touristic activities. Integrated geoelectrical survey was conducted to facilitate mapping the groundwater resources and the shallow subsurface structures in the area. Twenty-eight transient electromagnetic (TEM) soundings, three vertical electrical soundings (VES) and three electrical resistivity tomography (ERT) profiles were carried out around the Siliyin spring location. The dense cultivation, the rugged topography and the existence of infra structure in the area hindered acquiring more data. The TEM data were inverted jointly with the VES and ERT, and constrained by available geological information. Based on the inversion results, a set of geoelectrical cross-sections have been constructed. The shallow sand to sandy clay layer that forms the shallow aquifer has been completely mapped underneath and around the spring area. Flowing of water from the Siliyin spring is interconnected with the lateral lithological changes from clay to sand soil. Exploration of the extension of Siliyin spring zone is recommended. The interpretation emphasizes the importance of integrating the geoelectrical survey with the available geological information to obtain useful, cheap and fast lithological and structural subsurface information.

Metwaly, Mohamed; El-Qady, Gad; Massoud, Usama; El-Kenawy, Abeer; Matsushima, Jun; Al-Arifi, Nasser

2010-09-01

204

Calcareous benthonic foraminifera across the Cretaceous/Paleocene transition of Gebel Um El-Ghanayem, Kharga Oasis, Egypt  

NASA Astrophysics Data System (ADS)

The studies of benthic calcareous foraminifera of the Maastrichtian-early Paleocene Dakhla Formation in Gebel Um El-Ghanayem (Western Desert, Egypt), improve reconstruction of depositional environments of these successions. In total, 68 taxa of benthic foraminifera were identified in the studied succession. The late Maastrichtian assemblages (Zone CF3) are dominated by calcareous foraminifera with tapered tests, this tapered taxon Loxostomum applinae, Lox. tegulatum various dentalinid taxa, and Buliminella cushmani dominate in CF3 Biozone. We thus interpret these faunas as being dominated by infaunal morphogroups, suggesting a moderately eutrophic environment. Danian assemblages are characterized by abundant epifaunal trochospiral species, such as Cibicidoides abudurbensis, Cibicidoides farafraensis, and Gyroidinoides girardanus. The infaunal morphogroups make up 25-47% of fauna in the Danian, in contrast to 62-76% in the Upper Maastrichtian. This dominance of the Danian benthic foraminiferal assemblages by epifaunal or mixed epifaunal/infaunal morphogroups suggests that the food supply to the benthos was less abundant than in the latest Cretaceous. The Cretaceous/Paleocene boundary (K/Pg) is within the upper unit of the Lower Kharga Member and marked by a hiatus in at least the top of CF3 Zone of the Upper Maastrichtian to the Lower Paleocene (base Plc Zone).

Orabi, Orabi H.; Khalil, Hamza M.

2014-08-01

205

Monitoring land-use change-associated land development using multitemporal Landsat data and geoinformatics in Kom Ombo area, South Egypt  

Microsoft Academic Search

Due to the progressive increase in population, sustainable development of desert land in Egypt has become a strategic priority in order to meet the increasing demands of a growing population for food and housing. Such obligations require efficient compilation of accurate land-cover information in addition to detailed analysis of archival land-use changes over an extended time span. In this study,

Abdalla M. Faid; Abdulaziz M. Abdulaziz

2012-01-01

206

Deserts : geology and resources  

USGS Publications Warehouse

Approximately one-third of the Earth's land surface is desert, arid land with meager rainfall that supports only sparse vegetation and a limited population of people and animals. Deserts stark, sometimes mysterious worlds have been portrayed as fascinating environments of adventure and exploration from narratives such as that of Lawrence of Arabia to movies such as "Dune." These arid regions are called deserts because they are dry. They may be hot, they may be cold. They may be regions of sand or vast areas of rocks and gravel peppered with occasional plants. But deserts are always dry. Deserts are natural laboratories in which to study the interactions of wind and sometimes water on the arid surfaces of planets. They contain valuable mineral deposits that were formed in the arid environment or that were exposed by erosion. Because deserts are dry, they are ideal places for human artifacts and fossils to be preserved. Deserts are also fragile environments. The misuse of these lands is a serious and growing problem in parts of our world.

Walker, Alta Sharon

1996-01-01

207

A Desert Adventure  

NSDL National Science Digital Library

I hope you\\'re wearing either sunscreen or a winter coat and brought plenty of water with you, because we\\'re about to begin an adventure in the desert! I\\'ll bet you\\'re thinking that a desert is hot with lots of sand, but did you know that it can even snow in some deserts? In this adventure you\\'ll be learning more interesting facts about deserts and especially about the animals that live there. You will be tracking a desert animal on your journey and following its path. What does it do to survive in the environment of the desert? But be careful! Some of these animals can be dangerous... And most important, remember to HAVE FUN! TASK: After a day of following in the footsteps (or tracks) of your animal, you will be able to present the information to the other desert researchers in our class (thats everybody) and give them hints on the best ways to survive according to your animal. ...

Christensen, Ms. C.

2005-10-25

208

What is Desert RATS?  

NASA Video Gallery

The mission manager and test coordinators for the 2011 mission explain why Desert RATS was started 14 years ago, questions being studied in this year's activities, technologies being tested and the...

209

The Desert Blooms!  

NSDL National Science Digital Library

This activity attempts to clear up the common misconception that deserts are always hot, totally dry, and uninhabitable. Learners listen to poetry and use picture books and other resources to discover that the desert is actually full of life! Learners develop group and individual poems. This activity is featured on pp.27-29 of the "One With the Earth: Native Americans and the Natural World" multidisciplinary unit of study for kindergarten through third grade.

Indianapolis, The C.

2014-04-30

210

The Desert Blooms!  

NSDL National Science Digital Library

This activity attempts to clear up the common misconception that deserts are always hot, totally dry, and uninhabitable. Learners listen to poetry and use picture books and other resources to discover that the desert is actually full of life! Learners develop group and individual poems. This activity is featured on pp.27-29 of the "One With the Earth: Native Americans and the Natural World" multidisciplinary unit of study for kindergarten through third grade.

Indianapolis, The C.

2012-07-03

211

The Simpson, Strzelecki and Tirari Deserts: development and sand provenance  

NASA Astrophysics Data System (ADS)

Sands of the Simpson, Strzelecki and Tirari Deserts, central Australia, can be divided into two main groups on the basis of their physical and chemical characteristics (colour, grainsize, heavy minerals, quartz oxygen-isotope composition, zircon U-Pb ages). The first group encompasses the Strzelecki, Tirari and southeastern Simpson Deserts, while the second occupies the northern and the western Simpson Desert. The boundary between the two groups corresponds approximately to the northern-most extent of the Kallakoopah Lakes. Several lines of evidence suggest derivation of the sands mainly from local bedrock, with very little subsequent aeolian transport. Ultimate protosources for the sands, in order of importance, are: for the southeastern Simpson, Tirari and Strzelecki Deserts — the Tasman Orogenic System (New England and Lachlan Fold Belts, Georgetown Inlier), Musgrave and Arunta Blocks, Gawler and Curnamona Cratons; and for the north and western Simpson Desert — Arunta, Musgrave and Mount Isa Blocks and Tennant Creek Inlier. Sediment from the Tasman Orogenic System includes an additional `exotic' component from Palaeozoic sediments, probably derived mainly from Antarctica. Sediment transport from these protosources across the several hundred kilometres to the surficial sedimentary basins, was dominantly by fluvial, not aeolian, means. Quaternary aeolian transport or reworking has been minimal, serving only to form the dunes by vertical corrasion of underlying sedimentary rocks or residual products of local basement weathering. The deserts have received some recent localised sediment input from modern fluvial systems.

Pell, S. D.; Chivas, A. R.; Williams, I. S.

2000-01-01

212

DISTRIBUTIONAL CHANGES AND POPULATION STATUS FOR AMPHIBIANS IN THE EASTERN MOJAVE DESERT  

EPA Science Inventory

A number of amphibian species historically inhabited sparsely distributed wetlands in the Mojave Desert of western North America, habitats that have been dramatically altered or eliminated as a result of human activities. The population status and distributional changes for amphi...

213

Using Generic and Pesticide DRASTIC GIS-based models for vulnerability assessment of the Quaternary aquifer at Sohag, Egypt  

Microsoft Academic Search

Groundwater resources in the Sohag area, Egypt are currently threatened by contamination from municipal and industrial activities,\\u000a and agricultural pesticides. To cope with the growing population, there has been development in the desert zone on both sides\\u000a of the Nile Valley including agricultural investment areas, wastewater disposal sites, new urban areas, and industry. Use\\u000a of agrochemicals in the old cultivated

Ayman A. Ahmed

2009-01-01

214

Range and habitats of the desert tortoise  

USGS Publications Warehouse

We determined the current range of the desert tortoise (Gopherus agassizii) based on the available latest data from government agencies, the literature, and our experience. We developed the first detailed range map of this species and summarized information about habitat preferences. New records of occurrences were incorporated, and some peripheral localities of questionable authenticity were deleted. The distribution oCG. agassizii covers the broadest range of latitude, climatic regimes, habitats, and biotic regions of any North American tortoise. The northern portion ofits range is in the Mojave Desert of sDuth"eastern California, southern Nevada, southwestern Utah, and northwestern Arizona. The central portion of the range consists of several subdivisions of the Sonaran Desert in southeastern California, western and southern Arizona, and western Sonora, Mexico. The southern edge of its range is in the semitropical Sinaloan thornscrub and Sinaloan deciduous forest of eastern Sonora and northern Sinaloa, Mexico. This species has marked geogi-aphic differences but seems to construct burrows throughout its range.

Germano, D.J.; Bury, R.B.; Esque, T.C.; Fritts, T.H.

1994-01-01

215

Acute Sporadic Hepatitis E in Children Living in Cairo, Egypt. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

Seventy-three pediatric patients with acute hepatitis and 19 control patients without liver disease living in Cairo, Egypt, were evaluated with a newly developed Western blot assay for IgM antibody to hepatitis E virus (IgM anti-HEV). The mean age of acut...

K. C. Hyams M. C. McCarthy M. Kaur M. A. Purdy D. W. Bradley

1992-01-01

216

Geoenvironmental studies on conservation of archaeological sites at Siwa oasis, Egypt  

Microsoft Academic Search

Siwa oasis is located in the extreme western part of the Egyptian western desert. There are several archaeological sites in the oasis; the most distinct ones are Alexander the Great temple at Aghormi hill and the Gebel El Mota tomb excavations. They have suffered due to deterioration and cracks of different kinds and some parts are getting worse as rock

Hani A. M. Ibrahim; Gamal E. Kamh

2006-01-01

217

Representing Place: “Deserted Isles” and the Reproduction of Bikini Atoll  

Microsoft Academic Search

Bikini Atoll has been reshaped through time according to Western mythologies regarding “deserted” islands. Geographers have increasingly recognized that landscapes are shaped by the ways human agents conceptualize places. Ideals that shape places are not only based on interpretations of a given place, however, but are also formed by the semiotic linking of representations of similar landscapes. Conceptualizations of Bikini

Jeffrey Sasha Davis

2005-01-01

218

Eyewitness introduction to Egypt: "The gift of the Nile".  

PubMed

Northeastern corner of Africa, lying at the crossroads between the two continents of Europe and Asia (in the Sinai Peninsula), while bordering Libya, Sudan, Israel and the Red Sea. Egypt is the most ancient tourist country in the world. Several health fact-finding missions in the last few years were made to this small country that is frequently defined by the Valley of the Nile. With the spreading deserts on either side, or a very rich heritage of ancient relics, these scenic vistas are without equal elsewhere in the world. Although there are significant cultural differences among the population, Egypt has a long history of ethnic and religious compassion. Among the many rarities, main tourist attractions include the three great Pyramids of Giza and the Sphinx, amazing ancient wonders of the world. These fact-finding missions included how health and medical care are defined, how people and culture are intertwined with its physical features, land use, and the economy and its resources. PMID:19927898

Brown, Geraldine

2009-01-01

219

Egypt's falling IMR.  

PubMed

In Egypt, the infant mortality rate (IMR) has been reduced from 120/1000 live births in 1979 to 55/1000 births in 1988. This is one of the fastest declines of a country's IMR on record. A government commitment to increase per capita GNP and to meet the health and welfare needs of the people contributed to decline in the IMR. In the 1950s and 1960s, the Egyptian government executed a land reform program while it also assisted farmers with advice and extension services. These events greatly increased crop production which in turn led to an improvement in the people's quality of life. Other factors that helped the IMR to decrease were not planned. For example, employment opportunities expanded throughout the Middle East. Egyptians who took these jobs sent money back to their villages, therefore adding to the village's resources. As a result of this departure of manpower, real agricultural wages for the landless increased substantially. In addition, the highly motivated farmers increased production which caused an increase in jobs and demand for work. The US also played a significant role in the fall of the IMR. US aid concentrated on programs that would reduce the incidence of many infectious diseases that mostly strike infants and children 5 years old. Examples include immunization programs, village sanitation and safe water and drainage projects, and an oral rehydration project. The aforementioned examples of the Egyptian government and people's total commitment to the development of their economy and the improvement in the standard of living all contributed to the rapid decline of the IMR. PMID:12282155

1988-08-31

220

ASTER View of Sharm El Sheik, Egypt  

NASA Technical Reports Server (NTRS)

The Red Sea golf resort in Sharm El Sheik, Egypt, where President Clinton met with Israeli Prime Minister Ehud Barak and Palestinian Authority President Yasser Arafat, stands out against the desert landscape in this image acquired on August 25, 2000.

This image of the southern tip of the Sinai Peninsula shows an area about 30 by 40 kilometers (19 by 25 miles) in the visible and near infrared wavelength region. Vegetation appears in red. The blue areas in the water at the top and bottom of the image are coral reefs. The airport is visible just to the north of the golf resort.

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance.

2000-01-01

221

Educational Media Resources on Egypt.  

ERIC Educational Resources Information Center

This directory of instructional media on Egypt catalogues more than 400 items, including 16mm films, 8mm films, 35mm filmstrips, slide sets, audiotapes, video tapes, and kits. Materials are listed under appropriate headings and according to media type in the subject index. Annotations are included in the second part of the directory, which is…

Michigan Univ., Ann Arbor. Audio-Visual Education Center.

222

Geospatial Revolution: Food Deserts  

NSDL National Science Digital Library

Food deserts refer to a lack of easy access to nutritious food. They exist all over America as an outcome of poverty. This video from Penn State Public Broadcasting’s Geospatial Revolution shows how geospatial technology can help change this reality.

Wpsu

2010-11-11

223

Mojave Desert Diary  

ERIC Educational Resources Information Center

This is an account of a trip to the Mojave Desert sponsored by the California Youth Authority's Community Parole Center for wards who are selected on the basis of their potential for growth and their ability to make a connection between what they do in the wilderness and what they do on the streets. (PD)

Breed, Allen F.

1974-01-01

224

Desert Adaptations: Water  

NSDL National Science Digital Library

In this activity, students experiment with methods of water conservation by desert plants and animals. They will learn to observe a model situation and make inferences about real organisms, use a balance and record data, and describe and communicate observations relating to specialized organisms and interaction with a dry environment.

1998-01-01

225

U.S.-Egypt Security Cooperation after Egypt's January 2011 Revolution.  

National Technical Information Service (NTIS)

Could the leadership changes resulting from Egypt's January 2011 Revolution uproot 30 years of security cooperation between the United States and Egypt. This monograph examines how the security cooperation between the two countries, which is rooted in the...

S. S. Vogelsang

2011-01-01

226

Palynology and Stratigraphy of the Nubian Sandstone in Libya and Comparison with Egypt  

NASA Astrophysics Data System (ADS)

The so-called "Nubian Sandstone" outcrops along a wide area from Algeria to the Red Sea, forming two regressive phases. The lower phase is represented in Egypt by the Basal Clastic Unit, the Desert Rose Unit, the Abu Ballas Formation and the Matruh Shale. In Libya it is represented by the Mesak Sandstone, Sarir Sandstone, Cabao Sandstone and Kiklah Formation. In both countries, these successions are covered by a carbonate sequence, resulting from the Tethyan transgression during the Cenomanian. In Egypt however, the upper regressive phase is represented by the Taref Sandstone which was deposited during a brief period of active progradation, following the Tethyan incursion. This is not observed in Libya. Comparison of palynological studies in Libya with those documented by several authors in Egypt reveals that the "Nubian" facies in Libya were deposited before equivalent facies in Egypt. The Basal Clastic Unit, dated as Hautrauvian-Barremian, may be equivalent, at least to a part of the Neocomian Cabao Sandstone in NW Libya. Jarmah Member of the Mesak Formation in Libya was dated as Berriasian on the basis of Pilosisporites and Trilobosporites. This makes it older than any "Nubian" unit in Egypt. The Matruh Shale was assigned to the Aptian on the basis of Tricolpites, and the Abu Balls Formation 34 as Aptian-Albian on the basis of Tricolpites and Rousisporites radiatus. Whereas, there is no equivalent to the Aptian in NW Libya, the Aptian-Albian of Egypt is similar to Zone 1 of the Kiklah Formation and As Sarir Sandstone, which were dated as early Albian on the basis of Afropollis spp., and Perotriletes pannuceus, an Albian element not recorded in Egypt. The Plant Beds in southwestern Egypt were dated as Cenomanian on the basis of advanced angiosperm pollen. In Libya, equivalent bodies were considered Vraconian, representing the uppermost Albian, because it lacks Cenomanian pollen (e.g. Tricolpites mutabilis). Comparison of local sea-level changes with global sea-level curves is used to reconstruct paleogeography. Integration of palynology with geological data and tectonic implications indicates that, despite similarity in paleogeographic processes of the Nubian Sandstone, geological and structural settings remain different. The "Nubian Sandstone" provides a typical succession that can be studied in the light of sequence stratigraphy.

Tekbali, Ali; Hlal, Osama

2013-04-01

227

Snow, the Great River, and the Desert  

NASA Astrophysics Data System (ADS)

While many major rivers around the world originate from alpine snowpacks in mountain regions, some experience the extreme contrast of flowing through harsh desert environments downriver. One such stream is the Rio Grande which rises in the San Juan and the Sangre de Christo mountains of southern Colorado and northern New Mexico. Eventually, the snow fed Rio Grande flows through North America's largest desert, the Chihuahuan Desert in New Mexico, Texas, and Mexico, and simultaneously becomes part of the border between the United States and Mexico. As is often true, urban areas develop along the river corridors rather than in more inaccessible mountain regions. This demographic preference tends to isolate the vast majority of population in the Rio Grande, who are dependent on water for their livelihoods, from the mountain snowpacks where the flow is generated. Ironically then, snow is seldom viewed as the source of the much needed water flowing through the desert by the majority of the basin's population. In arid regions of the western U.S., water demand far exceeds the water supply, and water use is apportioned under the doctrine of prior appropriation with the oldest right getting the first use of water. The increasing population in urban areas does not usually have a right to use the water flowing through the desert unless water rights have been purchased by municipalities from the major category of water user in these basins, namely, irrigated agriculture. In the entire Rio Grande basin, irrigation makes up 80% of the consumptive use of water. Additionally, basin compacts and international treaties apportion water between states and countries. Because these formal agreements were based on above average runoff years, there is little flexibility in changing the use of water, particularly in dry to normal runoff years. Most of the older water rights in the Rio Grande, especially the upper basin, are supplied by snowmelt. This leaves the lower basin to depend upon rainfall-produced runoff occurring mostly during the sporadic summer monsoon season. Water harvesting techniques which promote heterogeneous water accumulation or production can effectively make more water available in certain areas at the expense the expense of nearby areas. The use of water ponding dikes on arid rangeland can promote increased native vegetation productivity through increases in soil moisture. Stock tanks lined with impervious material are also used to collect whatever runoff that is generated for later use. Desert dwellers living along rivers must rely on conservation measures and ingenuity in order to come up with a very limited water resource to survive. This survival is continually in doubt because population(and consequently water demand) continues to grow in these arid regions while the water supply remains relatively constant.

Rango, A.

2005-12-01

228

Desert Farming Benefits from Microbial Potential in Arid Soils and Promotes Diversity and Plant Health  

PubMed Central

Background To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. Methodology/Principal Findings We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt). Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90), and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37%) than in the desert (11%). Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%); disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. Conclusions/Significance After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural soil showed a higher diversity and a better ecosystem function for plant health but a loss of extremophilic bacteria. Interestingly, we detected that indigenous desert microorganisms promoted plant health in desert agro-ecosystems.

Koberl, Martina; Muller, Henry; Ramadan, Elshahat M.; Berg, Gabriele

2011-01-01

229

Environmental processes and spectral reflectance characteristics associated with soil erosion in desert fringe regions  

NASA Technical Reports Server (NTRS)

Results of analysis of spectral variation of sand dunes in El Ghorabi, Bahariya, Egypt; Tombouctou/Azaouad, Mali; and Tsodilo Hills, western Botswana are presented. Seasonal variations in dune extent and location of dune crests and their relationship to such factors as wind and weather variations are emphasized.

Jacobberger, P. A.

1987-01-01

230

Arizona-Sonora Desert Museum  

NSDL National Science Digital Library

The Arizona-Sonora Desert Museum is a zoo, natural history museum and botanical garden, whose mission is to inspire people to live in harmony with the natural world by fostering love, appreciation, and understanding of the Sonoran Desert. The Center for Sonoran Desert Studies conducts the educational and scientific functions of the Museum and is a hub for research, education and conservation of the Sonoran Desert Region. The Center's activities range from on-grounds and outreach education programs for school children and adults, to conducting ecological research in the Sonoran Desert region and advising museum staff, other conservation organizations, and the public on scientific and educational matters. The website has extensive information about desert ecology, environments, animals, and plants, with some content presented in Spanish. There are numerous programs and classes presented, hiking clubs, tours, and activities for Scouts.

231

A Desert Park  

NSDL National Science Digital Library

This National Park Service site describes the desert and oasis ecosystems of Joshua Tree National Park as well as the cultural history of humans occupying the area. Nature sections describe the animals, plants, cryptobiotic crusts, and the geology of the park. There are sections on environmental factors such as air quality, disturbed lands, exotic species and fire ecology. There is also information on natural history and cultural history education programs provided for different grade levels.

232

Regional geothermal exploration in Egypt  

NASA Technical Reports Server (NTRS)

A study is presented of the evaluation of the potential geothermal resources of Egypt using a thermal gradient/heat flow technique and a groundwater temperature/chemistry technique. Existing oil well bottom-hole temperature data, as well as subsurface temperature measurements in existing boreholes, were employed for the thermal gradient/heat flow investigation before special thermal gradient holes were drilled. The geographic range of the direct subsurface thermal measurements was extended by employing groundwater temperature and chemistry data. Results show the presence of a regional thermal high along the eastern margin of Egypt with a local thermal anomaly in this zone. It is suggested that the sandstones of the Nubian Formation may be a suitable reservoir for geothermal fluids. These findings indicate that temperatures of 150 C or higher may be found in this reservoir in the Gulf of Suez and Red Sea coastal zones where it lies at a depth of 4 km and deeper.

Morgan, P.; Boulos, F. K.; Swanberg, C. A.

1983-01-01

233

Jeeps Penetrating a Hostile Desert  

ERIC Educational Resources Information Center

Several jeeps are poised at base camp on the edge of a desert aiming to escort one of them as far as possible into the desert, while the others return to camp. They all have full tanks of gas and share their fuel to maximize penetration. In a friendly desert it is best to leave caches of fuel along the way to help returning jeeps. We solve the…

Bailey, Herb

2009-01-01

234

Factors influencing the rates, processes and magnitude of accumulation of carbon in desert soils  

NASA Technical Reports Server (NTRS)

This report summarizes research funded through NASA's Soil Landscape Climate Program which includes studies of the systematics of carbon storage and flux in the terrestrial environment, specifically terrestrial soils. Efforts focussed on the nature of carbon behavior in arid environments, where the majority of the carbon is present as inorganic carbon stored as pedogenic carbonate in desert calcic soils. Studies were supported of soils in two areas of western North America's major deserts: the Mojave Desert and the Chihuahuan Desert. Part 1 of this report summarizes the results of research conducted in the area of the Providence Mountains, California in the eastern Mojave Desert. Part 2 of this report summarizes the results of research in the Sevilleta Wildlife Refuge in central New Mexico, one of the sites of the UMN Biology Department's Long Term Ecological Research.

Mcfadden, Leslie D.

1994-01-01

235

WASTEWATER SAFE REUSE FOR IRRIGATION OF PLANTS SPECIES AND DESERTED SOILS IN AGRICULTURAL AND FOREST LAND OF WESTERN GREECE BY THE USE OF IN SITU MEASUREMENTS, LABORATORY, GIS AND GPS METHODS  

Microsoft Academic Search

The scope of this research was t? study the possibility of reuse of humid urban sewage effluents of the treated outflows of the municipal wastewater treatment plant (MWTP) of the Holy City of Messolonghi in Western Greece, for irrigation and especially in safe applications in soils and plants. In the research area have been examined various parameters that affect the

Ag. Filintas; I. Kalavrouziotis; J. Hatzopoulos

236

Workshop on Extraterrestrial Materials from Cold and Hot Deserts  

NASA Technical Reports Server (NTRS)

Since 1969 expeditions from Japan, the United States, and European countries have recovered more than 20,000 meteorite specimens from remote ice fields of Antarctica. They represent approximately 4000-6000 distinct falls, more than all non-Antarctic meteorite falls and finds combined. Recently many meteorite specimens of a new "population" have become available: meteorites from hot deserts. It turned out that suitable surfaces in hot deserts, like the Sahara in Africa, the Nullarbor Plain in Western and South Australia, or desert high plains of the U.S. (e.g., Roosevelt County, New Mexico), contain relatively high meteorite concentrations. For example, the 1985 Catalogue of Meteorites of the British Museum lists 20 meteorites from Algeria and Libya. Today, 1246 meteorites finds from these two countries have been published in MetBase 4.0. Four workshops in 1982, 1985, 1988, and 1989 have discussed the connections between Antarctic glaciology and Antarctic meteorites, and the differences between Antarctic meteorites and modem falls. In 1995, a workshop addressed differences between meteorites from Antarctica, hot deserts, and modem falls, and the implications of possible different parent populations, infall rates, and weathering processes. Since 1995 many more meteorites have been recovered from new areas of Antarctica and hot deserts around the world. Among these finds are several unusual and interesting specimens like lunar meteorites or SNCs of probable martian origin. The Annual Meeting of the Meteoritical Society took place in 1999 in Johannesburg, South Africa. As most of the recent desert finds originate from the Sahara, a special workshop was planned prior to this meeting in Africa. Topics discussed included micrometeorites, which have been collected in polar regions as well as directly in the upper atmosphere. The title "Workshop on Extraterrestrial Materials from Cold and Hot Deserts" was chosen and the following points were emphasized: (1) weathering processes, (2) terrestrial ages, (3) investigations of "unusual" meteorites, and (4) collection and curation.

Schultz, Ludolf (Editor); Franchi, Ian A. (Editor); Reid, Arch M. (Editor); Zolensky, Michael E. (Editor)

2000-01-01

237

Workshop on Extraterrestrial Materials from Cold and Hot Deserts  

NASA Technical Reports Server (NTRS)

Since 1969 expeditions from Japan, the United States, and European countries have recovered more than 20,000 meteorite specimens from remote ice fields of Antarctica. They represent approximately 4000-6000 distinct falls, more than all non-Antarctic meteorite falls and finds combined. Recently many meteorite specimens of a new "population" have become available: meteorites from hot deserts. It turned out that suitable surfaces in hot deserts, like the Sahara in Africa, the Nullarbor Plain in Western and South Australia, or desert high plains of the U.S. (e.g., Roosevelt County, New Mexico), contain relatively high meteorite concentrations. For example, the 1985 Catalog of Meteorites of the British Museum lists 20 meteorites from Algeria and Libya. Today, 1246 meteorites finds from these two countries have been published in MetBase 4.0. Four workshops in 1982, 1985, 1988, and 1989 have discussed the connections between Antarctic glaciology and Antarctic meteorites, and the differences between Antarctic meteorites and modern falls. In 1995, a workshop addressed differences between meteorites from Antarctica, hot deserts, and modem falls, and the implications of possible different parent populations, infall rates, and weathering processes. Since 1995 many more meteorites have been recovered from new areas of Antarctica and hot deserts around the world. Among these finds are several unusual and interesting specimens like lunar meteorites or SNCs of probable martian origin. The Annual Meeting of the Meteoritical Society took place in 1999 in Johannesburg, South Africa. As most of the recent desert finds originate from the Sahara, a special workshop was planned prior to this meeting in Africa. Topics discussed included micrometeorites, which have been collected in polar regions as well as directly in the upper atmosphere. The title "Workshop on Extraterrestrial Materials from Cold and Hot Deserts" was chosen and the following points were emphasized: (1) weathering processes, (2) terrestrial ages, (3) investigations of "unusual" meteorites, and (4) collection and curation.

Schultz, Ludolf (Editor); Franchi, Ian A. (Editor); Reid, Arch M. (Editor); Zolensky, Michael E. (Editor)

1999-01-01

238

Delineation of Shallow Subsurface Structure by Azimuthal Resistivity Sounding and Joint Inversion of VES-TEM Data: Case Study near Lake Qaroun, El Fayoum, Egypt  

Microsoft Academic Search

An azimuthal resistivity survey was conducted at the transition zone between the desert area and the cultivated land near\\u000a Lake Qaroun, Egypt. This area has been affected by an east-west trending fault system as indicated from the surface geology.\\u000a Apparent resistivity values were plotted along azimuth on a polar diagram. Resistivity anomalies, for most of the AB\\/2 values\\u000a with long

Usama Massoud; Gad El Qady; Mohamed Metwaly; Fernando Santos

2009-01-01

239

Egypt: Modern human origins and early civilizations  

Microsoft Academic Search

Wendorf, Fred, Romuald Schild, Angela E. Close, and Associates. Egypt during the Last Interglacial: The Middle Paleolithic of Bir Tarfawi and Bir Sahara East. New York: Plenum Press, 1993. xi + 596 pp. including chapter references and index. $95.00 cloth.Trigger, Bruce G. Early Civilizations: Ancient Egypt in Context. Cairo: The American University in Cairo Press, 1993. x + 158 pp.

Robert J. Wenke

1998-01-01

240

Country Analysis Briefs: Egypt, July 31, 2013.  

National Technical Information Service (NTIS)

Egypt is the largest oil producer in Africa that is not a member of the Organization of the Petroleum Exporting Countries (OPEC), and the second largest natural gas producer on the continent, following Algeria. Egypt plays a vital role in international en...

2013-01-01

241

Treatment of childhood diarrhea in rural Egypt  

Microsoft Academic Search

The Egypt National Control of Diarrheal Diseases Project, implemented between 1983 and 1991, is widely regarded as one of the most successful national oral rehydration programs. Data from a longitudinal household survey conducted in 1990–1991 in rural Egypt indicate substantial increases in both knowledge and use of oral rehydration salts during the 1980s. However, the same data show that treatment

Ray Langsten; Kenneth Hill

1995-01-01

242

The emergence of writing in Egypt  

Microsoft Academic Search

The cultural history of ancient Egypt is markedly different from that of contemporary Mesopotamia, and the adoption of the idea of writing by the Egyptians conforms to a general pattern, which shows the tendency of Egypt to adopt and perfect inventions made elsewhere in the Near East. Theories of a conquering ‘dynastic race’, which gave rise to Egyptian civilisation, are

John D. Ray

1986-01-01

243

Desertification Control and Management of Land Degradation in the Thar Desert of India  

Microsoft Academic Search

India has 2.34 million km2 of hot desert called Thar located in the north-western part of Rajasthan between latitudes 23°3' and 30°12' North and longitudes 63°30' and 70°18' East. The Indian desert is spreading annually over 12000 ha of productive land degrading it and slowly advancing towards the national capital New Delhi at the rate of 0.5 km per year.

Surendra Singh Chauhan

2003-01-01

244

Land suitability assessment for perennial crops using remote sensing and Geographic Information Systems: A case study in northwestern Egypt  

Microsoft Academic Search

The main objective of this study was to develop a Geographic Information Systems-based model for land suitability assessment for guava, olive and date palm in the North-western coast of Egypt. Soil, climatic and landscape database as well as satellite image have been integrated through Geographic Information Systems (GIS). A Landsat ETM+ image dated 2001, was classified using maximum likelihood classifier

A. Shalaby; Y. O. Ouma; R. Tateishi

2006-01-01

245

Serosurvey for HTLV-I Among High-Risk Populations and Normal Adults in Egypt. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

The prevalence of antibodies to human T-cell lymphotropic virus type I (HTLV-I) was determined in high-risk groups and normal adults in Egypt. Among 647 individuals tested, 6 (0.9%) were confirmed positive by western blot analysis. These included 2 (0.7%)...

N. T. Constantine M. F. Sheba A. L. Corwin R. S. Danahy J. D. Callahan

1991-01-01

246

Population, desert expanding.  

PubMed

The conditions of desert expansion in the Sahara are highlighted. On the southern border the desert is growing at a rate of 3-6 miles/year. This growth is encroaching on arable land in Ethiopia and Mauritania. The region loses up to 28,000 sq miles/year of farmland. 33% of Africa's fertile land is threatened. Land-use patterns are responsible for the deterioration of the soil. Traditional practices are not effective because the practices are not suitable for permanent farming. Farmers also have stopped environmentally sound practices such as letting the fields remain fallow in order to renew soil fertility. Nomads overgraze areas before moving on. A recent study by the World Bank's Africa Region Office was released; the report details some of the links between rapid population growth, poor agricultural performance, and environmental degradation. Soil conditions are such that valuable topsoil is blow away by the wind because the layer is too thin. Vegetation at the desert's edge is used for cooking purposes or for heating fuel. Tropical and savannah areas are depleted when tree replacement is inadequate. Only 9 trees are planted for every 100 removed. The report emphasized the role of women and children in contributing to population pressure by increased fertility. Women's work load is heavy and children are a help in alleviating some of the burden of domestic and agricultural work. There is hope in meeting demographic, agricultural, food security, and environmental objectives over the next 30 years if the needs of women are met. The needs include access to education for young women, lessening the work loads of women, and decreasing child mortality through improved health care and access to safe water. PMID:12285832

1992-01-01

247

Desert-Tropicals.com  

NSDL National Science Digital Library

Created by plant enthusiast Philippe Faucon, Desert-Tropicals.com is a well-designed website with information about, and pictures of, over 3,500 plants. Plant lists are organized by scientific and common name, succulents, xeriscape plants, palm trees, herbs, and trees. The plant lists are quite extensive, and each species receives its own description page with a nice close-up photo as well as brief information about family, frost and heat tolerance, sun exposure, origin, propagation, and more. The site also connects to articles, a Bulletin Board, Bookstore, and relevant links.

Faucon, Philippe

248

Lost in the Desert!  

NSDL National Science Digital Library

Students learn about the interconnectedness of the body, with a particular focus on the skin as one of the most important homeostatic organ systems, in this case study in which the protagonist sets out on a three-hour drive across the Arizona desert to meet his fiancee in California, and never shows up. The case was designed to be used with students in a lower-level anatomy and physiology class who are interested in pursuing careers in nursing, occupational therapy, and other health related fields.

Evans, David L.

2002-01-01

249

Desert Research Institute: Research  

NSDL National Science Digital Library

Operating as the nonprofit research campus of the University and Community College System of Nevada, the Desert Research Institute (DRI) conducts more than $27 million in environmental research each year with the help of its approximately 400 research faculty and support staff. The informational research page of the main Web site offers descriptions; publications; links; and other relevant facts from the various arms of the institute, which include the Division of Atmospheric Sciences, Division of Earth and Ecosystem, Division of Hydrologic Sciences, Center for Arid Lands Environmental Management, Center for Watersheds and Environmental Sustainability, and several others.

1969-12-31

250

Space Radar Image of Safsaf Oasis, Egypt  

NASA Technical Reports Server (NTRS)

This three-frequency space radar image of south-central Egypt demonstrates the unique capability of imaging radar to penetrate thin sand cover in arid regions to reveal hidden details below the surface. Nearly all of the structures seen in this image are invisible to the naked eye and to conventional optical satellite sensors. Features appear in various colors because the three separate radar wavelengths are able to penetrate the sand to different depths. Areas that appear red or orange are places that can be seen only by the longest wavelength, L-band, and they are the deepest of the buried structures. Field studies in this area indicate L-band can penetrate as much as 2 meters (6.5 feet) of very dry sand to image buried rock structures. Ancient drainage channels at the bottom of the image are filled with sand more than 2 meters (6.5 feet) thick and therefore appear dark because the radar waves cannot penetrate them. The fractured orange areas at the top of the image and the blue circular structures in the center of the image are granitic areas that may contain mineral ore deposits. Scientists are using the penetrating capabilities of radar imaging in desert areas in studies of structural geology, mineral exploration, ancient climates, water resources and archaeology. This image is 51.9 kilometers by 30.2 kilometers (32.2 miles by 18.7 miles) and is centered at 22.7 degrees north latitude, 29.3degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is X-band, vertically transmitted and received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 16, 1994, on board the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

1994-01-01

251

Space Radar Image of Giza Egypt - with enlargement  

NASA Technical Reports Server (NTRS)

This radar image shows the area west of the Nile River near Cairo, Egypt. The Nile River is the dark band along the right side of the image and it flows approximately due North from the bottom to the right. The boundary between dense urbanization and the desert can be clearly seen between the bright and dark areas in the center of the image. This boundary represents the approximate extent of yearly Nile flooding which played an important part in determining where people lived in ancient Egypt. This land usage pattern persists to this day. The pyramids at Giza appear as three bright triangles aligned with the image top just at the boundary of the urbanized area. They are also shown enlarged in the inset box in the top left of the image. The Great Pyramid of Khufu (Cheops in Greek) is the northern most of the three Giza pyramids. The side-looking radar illuminates the scene from the top, the two sides of the pyramids facing the radar reflect most of the energy back to the antenna and appear radar bright; the two sides away from the radar reflect less energy back and appear dark Two additional pyramids can be seen left of center in the lower portion of the image. The modern development in the desert on the left side of the image is the Sixth of October City, an area of factories and residences started by Anwar Sadat to relieve urban crowding. The image was taken on April 19, 1994 by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered on latitude 29.72 degrees North latitude and 30.83 degrees East longitude. The area shown is approximately 20 kilometers by 30 kilometers. The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is C-band horizontally transmitted, horizontally received; blue is C-band horizontally transmitted, vertically received.

1994-01-01

252

The Kamil Crater in Egypt  

NASA Astrophysics Data System (ADS)

We report on the detection in southern Egypt of an impact crater 45 meters in diameter with a pristine rayed structure. Such pristine structures are typically observed on atmosphereless rocky or icy planetary bodies in the solar system. This feature and the association with an iron meteorite impactor and shock metamorphism provides a unique picture of small-scale hypervelocity impacts on Earth’s crust. Contrary to current geophysical models, ground data indicate that iron meteorites with masses of the order of tens of tons can penetrate the atmosphere without substantial fragmentation.

Folco, Luigi; Di Martino, Mario; El Barkooky, Ahmed; D'Orazio, Massimo; Lethy, Ahmed; Urbini, Stefano; Nicolosi, Iacopo; Hafez, Mahfooz; Cordier, Carole; van Ginneken, Matthias; Zeoli, Antonio; Radwan, Ali M.; El Khrepy, Sami; El Gabry, Mohamed; Gomaa, Mahomoud; Barakat, Aly A.; Serra, Romano; El Sharkawi, Mohamed

2010-08-01

253

The Kamil Crater in Egypt.  

PubMed

We report on the detection in southern Egypt of an impact crater 45 meters in diameter with a pristine rayed structure. Such pristine structures are typically observed on atmosphereless rocky or icy planetary bodies in the solar system. This feature and the association with an iron meteorite impactor and shock metamorphism provides a unique picture of small-scale hypervelocity impacts on Earth's crust. Contrary to current geophysical models, ground data indicate that iron meteorites with masses of the order of tens of tons can penetrate the atmosphere without substantial fragmentation. PMID:20651117

Folco, Luigi; Di Martino, Mario; El Barkooky, Ahmed; D'Orazio, Massimo; Lethy, Ahmed; Urbini, Stefano; Nicolosi, Iacopo; Hafez, Mahfooz; Cordier, Carole; van Ginneken, Matthias; Zeoli, Antonio; Radwan, Ali M; El Khrepy, Sami; El Gabry, Mohamed; Gomaa, Mahomoud; Barakat, Aly A; Serra, Romano; El Sharkawi, Mohamed

2010-08-13

254

Faunal remains from a Middle Pleistocene lacustrine marl in Dakhleh Oasis, Egypt: palaeoenvironmental reconstructions  

Microsoft Academic Search

Vertebrates and invertebrates associated with lithic artifacts are reported from a later middle Pleistocene horizon in Dakhleh Oasis, probably dating to isotope stage 7. This represents the first middle Pleistocene fauna of this stage from a site in the Egyptian Western Desert and demonstrates the presence of extensive permanent lakes along the margin of the Libyan Escarpment. The fauna includes

C. S Churcher; M. R Kleindienst; H. P Schwarcz

1999-01-01

255

Geoenvironmental studies on conservation of archaeological sites at Siwa oasis, Egypt  

Microsoft Academic Search

Siwa oasis is located in the extreme western part of the Egyptian western desert. There are several archaeological sites in\\u000a the oasis; the most distinct ones are Alexander the Great temple at Aghormi hill and the Gebel El Mota tomb excavations. They\\u000a have suffered due to deterioration and cracks of different kinds and some parts are getting worse as rock

Hani A. M. Ibrahim; Gamal E. Kamh

2006-01-01

256

Mojave Desert Ecosystem Project  

NSDL National Science Digital Library

A Department of Defense (DOD) program, the Mojave Ecosystem Database Program (MEDP) represents the DOD's "first attempt to meld together a shared scientific database that can be used to affect dynamic sustainable land management decisions." Although the mission statement of MEDP reflects a somewhat oxymoronic goal, e.g., maintaining "critical DOD installations within the Mojave Desert Ecosystem ... while protecting the environment," the site nevertheless represents an opportunity for researchers to access environmental models and potentially influence land management within the Mojave Ecoregion. The searchable site offers information about and/or access to Geospatial Data, Metadata, Geomorphic Landform Data, and a Spatial Bibliography, among other regional resources. An excellent selection of links points users to a wealth of additional and variously detailed (governmental) information.

257

Natural radioactivity and dose assessment for phosphate rocks from Wadi El-Mashash and El-Mahamid Mines, Egypt  

Microsoft Academic Search

The activity concentrations of 226Ra, 232Th and 40K have been measured by gamma spectroscopy (sodium iodide NaI(Tl) detector) in phosphate rock samples, collected from the Wadi El-Mashash, a site located in the central eastern desert, and El-Mahamid in the Nile valley, Egypt. The average activity concentrations of 226Ra, 232Th and 40K (Bqkg?1) in phosphate rocks were 665.8±33.4, 329.4±17 and 587.6±29.4

Adel G. E. Abbady; M. A. M. Uosif; A. El-Taher

2005-01-01

258

Agribusiness Linkages for Egypt Final Report.  

National Technical Information Service (NTIS)

Started in 1996, Agribusiness Linkages for Egypt (AgLink) was a seven-year initiative which made an impressive contribution to transforming and strengthening the Egyptian livestock sector at all levels, increasing the quality and availability of milk and ...

2004-01-01

259

Economics of Processing Tomatoes in Egypt.  

National Technical Information Service (NTIS)

The report in Arabic has an English summary. Consumption of processed tomato products has been rising dramatically, leading to sharply increased imports. Egypt processes only about 1 percent of its tomato production; the industry currently is not economic...

A. K. M. Ashry

1983-01-01

260

Keeping the desert at bay  

SciTech Connect

Man-made desert (areas that are no longer productive) has increased the world's deserts from 36.3 to 43% of the land surface. Desertification involves ecological degradation that makes the land less productive or allows an uneconomic type of vegetation, such as mesquite, to replace an economic plant. The process was first thought to be an encroachment by expanding deserts, but, except for the movement of sand dunes, desertification is now viewed as productive land that deteriorated and was added to the desert. Land is lost to agriculture by erosion, loss of nutrients, compaction, salination, urban development, and pollution. The interacting biosphere, technosphere, and social sphere form the framework of man's existence. An understanding of this framework is crucial to those offering technological assistance to developing countries. (DCK)

El-Kassas, M.

1981-02-01

261

Egypt Nile delta gas plays take off  

SciTech Connect

This paper reviews the exploration and resource potential of Egypt`s Nile delta as a major gas/condensate province. It discusses the various company`s involved in developing these resources and their plans for exploitation. It reviews the drilling in the area and gives a summary of the reservoir geology of the areas. It identifies the major discoveries as they relate to the various reservoirs in the delta area.

Petzet, G.A.

1996-08-26

262

Desert Life in the American Southwest  

NSDL National Science Digital Library

DesertUSA.com (DUSA) provides this interesting site, offering a plethora of general information on the deserts of the United States. Designed as an educational tool for discovering "the beauty, life and culture of North American deserts," the site contains illustrated text, factual summaries, virtual reality tours, movie/audio clips, and stories. All materials focus on desert-related topics, including plants, animals, geology, cultural and natural history, and parks, among others. The site has much to offer -- from the basics of the desert environment, to a photo-illustrated guide of desert flora and fauna, to details on specific arid and semi-arid deserts of the American Southwest. A glossary of desert terms and brief descriptions of features of the Chihuahuan, Great Basin, Mojave and Sonoran Deserts round out the site.

263

Mate desertion in the snail kite  

USGS Publications Warehouse

Mate desertion during the breeding cycle was documented at 28 of 36 (78%) snail kite, Rostrhamus sociabilis nests in Florida between 1979 and 1983. Offspring mortality occurred at only one deserted nest, however. Parents that were deserted by their mates continued to care for their young until independence (3?5 additional weeks) and provided snails at a rate similar to that of both parents combined before desertion. Males and females deserted with nearly equal frequency, except in 1982 when more females deserted. No desertion occurred during drought years, whereas desertion occurred at nearly every nest during favourable conditions. The occurrence of mate desertion was generally related to indirect measures of snail abundance: foraging range, snail delivery rates to the young and growth rates. Small broods were deserted more frequently by females than by males and tended to be deserted earlier than large ones. After desertion, deserters had the opportunity to re-mate and nest again since breeding seasons were commonly lengthy, but whether they did so was impossible to determine conclusively in most cases. The deserted bird sometimes incurred increased energetic costs and lost breeding opportunities during periods of monoparental care.

Beissinger, S.R.; Snyder, N.F.R.

1988-01-01

264

Gujarat, Western India  

NASA Technical Reports Server (NTRS)

Extremely high sediment loads are delivered to the Arabian Sea along the coast of Pakistan (upper left) and western India. In the case of the Indus River (far upper left) this sedimentation, containing large quantities of desert sand, combines with wave action to create a large sand-bar like delta. In the arid environment, the delta lacks much vegetation, but contains numerous mangrove-lined channels. This true-color image from May 2001 shows the transition from India's arid northwest to the wetter regions farther south along the coast. The increase in vegetation along the coast is brought about by the moisture trapping effect of the Western Ghats Mountain Range that runs north-south along the coast. Heavy sediment is visible in the Gulf of Kachchh (north) and the Gulf of Khambhat(south), which surround the Gujarat Peninsula.

2002-01-01

265

Suicide trends in Upper Egypt.  

PubMed

Suicide is an important problem, ranking among the top 10 causes of death for individuals in all ages in developed countries. This article is a retrospective study evaluating suicide cases in Assiut, one of the largest provinces in Egypt, from 2005 to 2009. There were 117 cases, of which involved 68 male victims (58.12%) and 49 women (41.88%). Suicide rates ranged from 0.6 to 0.8 per 100,000. Age predominance was from 20 to ?30 years. The method of suicide was different between male and female victims, as male victims tried to use more violent methods than females. The most common cause of death in men was usage of toxins and by hanging 29% and 28%, respectively, while in women was usage of toxins (70%). This study showed that suicide rates have increased since 1987, indicating a grave problem that needs to be solved. PMID:22900760

Abdel Moneim, Wafaa M; Yassa, Heba A; George, Safaa M

2012-09-01

266

Hydrological and climatic changes in deserts of China since the late Pleistocene  

NASA Astrophysics Data System (ADS)

Large areas in western China were wetlands or less arid between 40 and 30 ka, corresponding to the "Greatest Lake Period" on the adjacent Tibetan Plateau. During the last glacial maximum, some of these western Chinese deserts again experienced wetter conditions; however, at the same time the sandy lands in the eastern Chinese desert belt experienced an activation of aeolian dunes. While interpretations of the mid-Holocene environment in the deserts of China are controversial, it is quite likely that it was more humid not only in the eastern areas influenced by monsoon climate systems but also in the western deserts where moisture is currently associated with westerlies. Evaluation of lacustrine records in the lakes recharged by dryland rivers and the complex interactions of these systems, as well as other paleoenvironmental proxies such as the Artemisia/Chenopodiaceae ratio, should be interpreted with greater caution. Facing the highlighted uncertainties in our understanding of climate changes in Chinese deserts, it is hoped that this special issue will improve our knowledge considerably.

Yang, Xiaoping; Scuderi, Louis A.

2010-01-01

267

Economic Efficiency of Cotton Production and Ginning in Egypt.  

National Technical Information Service (NTIS)

Cotton is Egypt's most important crop representing one-fourth of the value of all field crops. The paper addresses major policy questions about cotton production and ginning in Egypt using comparative advantage analysis. Domestic resource cost (DRC), whic...

H. Khedr H. Kheir-El-Din E. Monke

1982-01-01

268

Socio-Economic Activities of Land Reclamation Cooperatives in Egypt.  

National Technical Information Service (NTIS)

The paper is one of several assessing the role and performance of agricultural cooperatives in Egypt. The increase in reclaimed agricultural land in Egypt has required a special type of cooperative; the members receive and farm parcels under cooperative m...

A. H. A. Sharshar

1983-01-01

269

Desert and desertification in Iran  

NASA Astrophysics Data System (ADS)

One of the greatest environmental concerns in Iran as in other arid and semiarid countries is the transformation of once productive, or marginally productive, land to deteriorated land and soil unable to support plants and animals. Because the land becomes barren and dry, the process is described as desertification, which occurs as a sequence of events. The area of deserts in Iran is about 340,000 Km2 (less than one fifth of its total area), of which 100,000 Km2 is being used for some cultivation, 120,000 Km2 is subjected to moving sands about 40 % of which is active sand dunes. Most of features and processes usual in world famous deserts are also observed in Iran: low precipitation, high evaporation, poor or lack of vegetation, saline and alkaline soils, low population and small and sparse oases. The deserts of Iran are generally classified in the subtropical, warm, arid and semiarid group, but the effect and presence of some geographical and geoclimatical factors such as height, vicinity to Indian Ocean and so on do some changes in climatic conditions and geographical features causing some local and regional differences in them. Geographically, two groups of deserts have been known in Iran: (1) Coastal deserts which, like a ribbon with variable width, stretch from extreme southeast to extreme southwest, at the north parts of Oman Sea and Persian Gulf. One important feature of these deserts is relatively high humidity which differentiates them from other deserts. This causes an increase in vegetation coverage and hence a decrease in eolian erosion and also a dominance of chemical weathering to that of physical. (2) internal deserts, which rest in central, eastern and southeastern plateau of the country and in independent and semi dependent depressions. This situation, which is due to the surrounding high mountains, blocks humidity entry and causes the aridity of these deserts. Wind as a dominant process in the area causes deflated features such as Reg (desert pavement), Kalut (Yardang), Hoodoo and wind deposited features such as different kinds of sand dunes (Seif, Nebka, Rebdous, Barkhan, Ghourd, Erg) and Loess, most of which exhibit beautiful landscapes suitable for ecotourism and scientific tours. Salt deserts (Kavir or Playas), which rest in the lowest parts of internal depressions, are the most current features in Iran deserts. The most extensive and specific salt deserts are in the course of floods or at the end of them, which consist of fine grained sediments in the lowest parts of the depressions. Many factors have been participated in the formation of salt deserts in Iran, the most important of which, are morphotectonical (such as folding and faulting due to the last epirogenic and orogenic movements), climatical and hydrological (occurred in Quaternary), geological and pedological (such as the presence of Neogene evaporitic formations).

Bahrami, M.

2009-04-01

270

Nonfarm Income, Inequality, and Poverty in Rural Egypt and Jordan  

Microsoft Academic Search

Nonfarm income has a greater impact on poverty and inequality in Egypt than in Jordan. In rural Egypt the poor receive almost 60 percent of their income from nonfarm sources, while in rural Jordan they receive less than 20 percent. The reason for this difference is land: in rural Egypt, agricultural land is very productive, but access is quite limited,

Richard H. Adams

2001-01-01

271

The Landscape Evolution of Ulan Buh Desert in North China during Late Quaternary  

NASA Astrophysics Data System (ADS)

Desert evolution was one of the major environmental changes in northern China during Quaternary. Ulan Buh Desert (UBD), at margin of present summer monsoon, is one of main desert fields and dust source areas in the north and northwest China. In this paper we present the results of lithology, Optical Stimulated Luminescence (OSL) dates, grain-size, carbonate content, organic content and pollen analysis from the drilling cores in the different parts of UBD. Our results show that most area of the present Ulan Buh desert was covered by the Jilantai-Hetao mage-paleolake before ~90 ka ago, a uniform paleolake of about 34,000 km2 covering the whole Hetai palin, and sevrious eolian and desert environment was prevailing during the last glacial and early Holoccene. Then an Ulan Buh paleolake (UB paleolake), likely a desert-wetland enviroment, formed in the northern part of UBD and Jilantai salt lake at around 8-7 ka, leaving dry lake bed landform in northern UBD, while high dune landscape probably prevailed in south UBD. After that, the mordern UBD landscape formed. The Jilantai Salt Lake in western UBD continued to exist until present with high lake level during UB paleolake preiod. During the recent 2000 years aeolian sand from Badan Jaran desert invaded the north UBD through Langshan mountain to form dune landform covered on dry UB paleolake bed and seperated main Ulan Buh desert and Jilantai Salt Lake. Human activities such as changing low wetland to farmland and following abandonment resulted the formation of easten Ulan Buh desert in Han dynasty since 200 BC. The formation of UBD landfporms was suggedted to be relate to disintegration of Jilantai-Hetao mage-paleolake, and was also likely to corresponding to summer monsoon changes during during last glacial and Holocene.

Chen, Fahu; Li, Guoqiang; Zhao, Hui; Jin, Ming; Fan, Yuxin; Madsen, David; Chun, Xi

2013-04-01

272

Analysis of utilization of desert habitats with dynamic simulation  

USGS Publications Warehouse

The effects of climate and herbivores on cool desert shrubs in north-western Utah were investigated with a dynamic simulation model. Cool desert shrublands are extensively managed as grazing lands, and are defoliated annually by domestic livestock. A primary production model was used to simulate harvest yields and shrub responses under a variety of climatic regimes and defoliation patterns. The model consists of six plant components, and it is based on equations of growth analysis. Plant responses were simulated under various combinations of 20 annual weather patterns and 14 defoliation strategies. Results of the simulations exhibit some unexpected linearities in model behavior, and emphasize the importance of both the pattern of climate and the level of plant vigor in determining optimal harvest strategies. Model behaviors are interpreted in terms of shrub morphology, physiology and ecology.

Williams, B.K.

1986-01-01

273

Radar attenuation in desert soil  

NASA Astrophysics Data System (ADS)

Soil properties make a significant impact in the observed responses of various sensors for subsurface target detection. Ground penetrating radars (GPRs) have been extensively researched as a tool for subsurface target detection. A key soil parameter of interest for evaluating GPR performance is the soil attenuation rate. The information about the soil attenuation rate coupled with target properties (size, shape, material properties and depth of burial) can be used to estimate the effectiveness of radar sensors in a particular soil environment. Radar attenuation in desert soil is of interest in today's political and military climate. Laboratory measurements of desert soil attenuation were conducted using samples collected from a desert in Southwestern United States and in Iraq. These measurements were made in a coaxial waveguide over the frequency ranging from 250 MHz to 4 GHz. The soil grain size distribution, mineralogy, moisture and salinity were also measured. This report describes the experimental procedure and presents the radar attenuation rates observed in desert soils. The results show that the soluble salt content is an important parameter affecting the attenuation behavior of desert soils.

Koh, Gary

2008-05-01

274

Diversity and adaptations in the Mojave desert  

NSDL National Science Digital Library

Deserts are characterized by low humidity, little rainfall, extreme temperatures, and a small amount of vegetation. However, deserts are not "dead zones" and host a variety of organisms adapted to these conditions.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-13

275

Pinacate beetle from the Mojave desert  

NSDL National Science Digital Library

The beetle's outer covering helps it survive in the harsh desert environment. These beetles also give off an unpleasant smell to deter predators. Beetles and other insects are eaten in the desert for their water and nutrient content.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-13

276

Native Perennial Grass Communities of the Carson Desert of Northwestern Nevada  

Microsoft Academic Search

Ahstract-A generalized distribution of the perennial grasses in the western Great Basin reveals an inter-mixing of species of the two grass Tribes Hordeae and Agrostideae (following the nomencla­ ture of Hitchcock 1950). The dominant genera are Agropyron and Achnatherum -Hesperostipa. In the Lahontan trough of the Carson Desert, a third Tribe of grasses, Zoysieae, is represented by Hilaria jamesii. The

James A. Young; Charlie D. Clements

1999-01-01

277

BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS FROM DESERT VEGETATION OF THE SOUTHWESTERN U.S.  

EPA Science Inventory

Thirteen common plant species in the Mojave and Sonoran Desert regions of the western United States were tested for emissions of biogenic non-methane volatile organic compounds (BVOCs). Only two of the species examined emitted isoprene at rates of 10 µgCg?1 ...

278

Geographic overview: Climate, phenology, and disturbance regimes in steppe and desert communities  

Microsoft Academic Search

In midwestern steppes, precipitation peaks in summer, whereas west of the Rocky Mountains, steppes are characterized by summer drought. In western deserts, the amount of precipitation is highly variable. These different climatic regimes result in differences in prevalence of and resilience to disturbances such as herbivory, and differences in susceptibility to invasion by exotic plants and animals. The timing and

B. J. Weddell

279

Water relations and photosynthesis of a barrel cactus, Ferocactus acanthodes , in the Colorado desert  

Microsoft Academic Search

The structural characteristics, water relations, and photosynthesis of Ferocactus acanthodes (Lemaire) Britton and Rose, a barrel cactus exhibiting Crassulacean acid metabolism (CAM), were examined in its native habitat in the western Colorado desert. Water storage in its succulent stem permitted nighttime stomatal opening ot continue for about 40 days after the soil water potential became less than that of the

Park S. Nobel

1977-01-01

280

Feasibility and Implications of a Rock Coating Catena: Analysis of a Desert Hillslope.  

National Technical Information Service (NTIS)

This research analyzes rock coatings on a basaltic hill in the western Mojave Desert using a combination of aerial imagery, a new method of digital in-field' ground-based image processing, and statistical analyses. In addition, this research resulted in t...

R. E. Palmer

2002-01-01

281

Desert-Adapted Crocs Found in Africa  

NSDL National Science Digital Library

This National Geographic site details the discovery of several small communities of crocodiles living on the southern edge of Africa's Sahara in desert conditions. The desert crocodiles have apparently adapted to the changing environment in northern Africa; 8,000 to 10,000 years ago, what is now desert was probably lush savannah and grasslands.

Mayell, Hillary; News, National G.

282

Status Assessment and Conservation Plan for the Western Burrowing Owl in the United States.  

National Technical Information Service (NTIS)

The Western Burrowing Owl (Athene cunicularia hypugaea) is a grassland specialist distributed throughout w. North America, primarily in open areas with short vegetation and bare ground in desert, grassland, and shrub-steppe environments. Burrowing Owls ar...

D. S. Klute L. W. Ayers M. T. Green S. L. Jones W. H. Howe

2003-01-01

283

Eastern Egypt, Red Sea and Saudi Arabia  

NASA Technical Reports Server (NTRS)

Eastern Egypt, the Red Sea and Saudi Arabia can all be seen in this single view of the Near East (26.5N, 36.5E). Not since The Gemini XI photo taken in 1966, have NASA astronauts been able to capture such a scope of the Earth's surface as this mission provided from its 330 nautical mile orbit. Easily seen from this vantage point is eastern Egypt, the Nile River, Lake Nassar, the Red Sea and almost half of Saudi Arabia.

1990-01-01

284

Modeling Soil Moisture in the Mojave Desert  

USGS Publications Warehouse

The Mojave Desert is an arid region of southeastern California and parts of Nevada, Arizona, and Utah; the desert occupies more than 25,000 square miles (fig. 1). Ranging from below sea level to over 5,000 feet (1,524 m) in elevation, the Mojave Desert is considered a ?high desert.? On the west and southwest it is bounded by the Sierra Nevada, the San Gabriel, and the San Bernardino Mountains. These imposing mountains intercept moisture traveling inland from the Pacific Ocean, producing arid conditions characterized by extreme fluctuations in daily temperatures, strong seasonal winds, and an average annual precipitation of less than six inches. The Mojave Desert lies farther south and at a lower elevation than the cooler Great Basin Desert and grades southward into the even lower and hotter Sonoran Desert.

Miller, David M.; Hughson, Debra; Schmidt, Kevin M.

2008-01-01

285

The Sonoran Desert, Arizona Upland  

NSDL National Science Digital Library

This tutorial explains the ecosystem of the Arizona Upland region of the Sonoran Desert and describes the plants and animals that live there. Students will discover the interactions of the living and non-living parts of the ecosystem. There is an interactive glossary within the text.

286

Mortality, Recruitment and Change of Desert Tree Populations in a Hyper-Arid Environment  

PubMed Central

Background Long-term vegetation changes in hyper-arid areas have long been neglected. Mortality, recruitment and change in populations of the ecologically and culturally important and drought persistent Acacia tortilis and Balanites aegyptiaca are therefore estimated in the Eastern Desert of Egypt, and are related to the primary agents of change, water conditions and human intervention. Methodology A change analysis using high-resolution Corona images (1965) in combination with field data (2003) is the basis for recruitment, mortality and change estimates. For assessing the influence of water conditions on patterns in recruitment and survival, different types of generalized linear models are tested. Conclusions The overall trend in population size in that part of the Eastern Desert studied here is negative. At some sites this negative trend is alarming, because the reduction in mature trees is substantial (>50%) at the same time as recruitment is nearly absent. At a few sites there is a positive trend and better recruitment. Frequent observations of sprouting in saplings indicate that this is an important mechanism to increase their persistence. It is the establishment itself that seems to be the main challenge in the recruitment process. There are indications that hydrological variables and surface water in particular can explain some of the observed pattern in mortality, but our results indicate that direct human intervention, i.e., charcoal production, is the main cause of tree mortality in the Eastern Desert.

Andersen, Gidske L.; Krzywinski, Knut

2007-01-01

287

Mesozoic evolution of the northeast African shelf margin, Libya and Egypt  

SciTech Connect

The present tectonic features of the northeast African shelf margin between the Nile delta and the Gulf of Sirte are products of (1) precursory late Paleozoic basement arches, (2) early Mesozoic rifting and plate separation, and (3) Late Cretaceous structural inversion. Isopach and structural maps, cross sections, and sediment accumulation (geohistory) curves constructed from 89 wells in the Western Desert and 27 wells in northeastern Libya depict the structural and stratigraphic development of the northeast African shelf margin.

Aadland, R.K.; Schamel, S.

1988-08-01

288

ESR signal intensity and crystallinity of quartz from Gobi and sandy deserts in East Asia and implication for tracing Asian dust provenance  

NASA Astrophysics Data System (ADS)

Electron spin resonance (ESR) signal intensity and crystallinity index (CI) of fine- (<16 µm) and coarse-grained (>16 µm) quartz were measured in surface samples from the Taklimakan desert in western China, the Badain Juran, Tengger and Mu Us deserts in northern China, and the Gobi desert in southern Mongolia to evaluate whether these geophysical parameters can serve as reliable provenance tracers of Asian dust. The results indicate that spatial variability of both ESR signal intensity and CI is evident within the Taklimakan deserts and the Mongolian Gobi, but less significant in the three deserts of northern China. Coarse-grained quartz from the Mongolian Gobi and northern China deserts can be differentiated from the Taklimakan desert using the ESR signal intensity. Fine-grained quartz originating from three major Asian dust sources, i.e., the Gobi-sandy deserts in western China, northern China and southern Mongolia, can be distinguished effectively using the combination of ESR and CI signals. Our results suggest that ESR signal intensity and CI can discriminate the sources of fine-grained quartz better than coarse-grained quartz, providing an effective approach to trace the provenance of fine-grained dust deposition on the land and in the ocean.

Sun, Youbin; Chen, Hongyun; Tada, Ryuji; Weiss, Dominik; Lin, Min; Toyoda, Shin; Yan, Yan; Isozaki, Yuko

2013-08-01

289

Phylogeography of Beck's Desert Scorpion, Paruroctonus becki, reveals Pliocene diversification in the Eastern California Shear Zone and postglacial expansion in the Great Basin Desert.  

PubMed

The distribution of Beck's Desert Scorpion, Paruroctonus becki (Gertsch and Allred, 1965), spans the 'warm' Mojave Desert and the western portion of the 'cold' Great Basin Desert. We used genetic analyses and species distribution modeling to test whether P. becki persisted in the Great Basin Desert during the Last Glacial Maximum (LGM), or colonized the area as glacial conditions retreated and the climate warmed. Phylogenetic and network analyses of mitochondrial cytochrome c oxidase 1 (cox1), 16S rDNA, and nuclear internal transcribed spacer (ITS-2) DNA sequences uncovered five geographically-structured groups in P. becki with varying degrees of statistical support. Molecular clock estimates and the geographical arrangement of three of the groups suggested that Pliocene geological events in the tectonically dynamic Eastern California Shear Zone may have driven diversification by vicariance. Diversification was estimated to have continued through the Pleistocene, during which a group endemic to the western Great Basin diverged from a related group in the eastern Mojave Desert and western Colorado Plateau. Demographic and network analyses suggested that P. becki underwent a recent expansion in the Great Basin. According to a landscape interpolation of genetic distances, this expansion appears to have occurred from the northwest, implying that P. becki may have persisted in part of the Great Basin during the LGM. This prediction is supported by species distribution models which suggest that climate was unsuitable throughout most of the Great Basin during the LGM, but that small patches of suitable climate may have remained in areas of the Lahontan Trough. PMID:23933071

Graham, Matthew R; Jaeger, Jef R; Prendini, Lorenzo; Riddle, Brett R

2013-12-01

290

Leptospires Isolated from Wild Mammals in Egypt.  

National Technical Information Service (NTIS)

In a leptospire survey of 364 wild mammals (12) species from Egypt, serotype isolates were 7 of grippotyphosa from mice (Mus musculus) and 3 of icterohaemorrhagiae from 2 mongooses (Herpestes i. ichneumon) and 1 fox (Vulpes v. niloticus), Antibodies to th...

I. S. Barsoum R. W. Moch B. A. M. Botros M. N. Kaiser

1973-01-01

291

Agricultural Trade Policy in Contemporary Egypt.  

National Technical Information Service (NTIS)

The paper discussed both traditional (i.e., cotton and rice) and new (i.e., horticultural) crop exports of Egypt. Three main themes were addressed for each group--comparative advantage, international market composition, and the structure and policy of Egy...

H. A. Khedr T. E. Petzel

1982-01-01

292

Review of parasitic zoonoses in egypt.  

PubMed

This review presents a comprehensive picture of the zoonotic parasitic diseases in Egypt, with particular reference to their relative prevalence among humans, animal reservoirs of infection, and sources of human infection. A review of the available literature indicates that many parasitic zoonoses are endemic in Egypt. Intestinal infections of parasitic zoonoses are widespread and are the leading cause of diarrhea, particularly among children and residents of rural areas. Some parasitic zoonoses are confined to specific geographic areas in Egypt, such as cutaneous leishmaniasis and zoonotic babesiosis in the Sinai. Other areas have a past history of a certain parasitic zoonoses, such as visceral leishmaniasis in the El-Agamy area in Alexandria. As a result of the implementation of control programs, a marked decrease in the prevalence of other zoonoses, such as schistosomiasis and fascioliasis has been observed. Animal reservoirs of parasitic zoonoses have been identified in Egypt, especially in rodents, stray dogs and cats, as well as vectors, typically mosquitoes and ticks, which constitute potential risks for disease transmission. Prevention and control programs against sources and reservoirs of zoonoses should be planned by public health and veterinary officers based on reliable information from systematic surveillance. PMID:24808742

Youssef, Ahmed I; Uga, Shoji

2014-03-01

293

Review of Parasitic Zoonoses in Egypt  

PubMed Central

This review presents a comprehensive picture of the zoonotic parasitic diseases in Egypt, with particular reference to their relative prevalence among humans, animal reservoirs of infection, and sources of human infection. A review of the available literature indicates that many parasitic zoonoses are endemic in Egypt. Intestinal infections of parasitic zoonoses are widespread and are the leading cause of diarrhea, particularly among children and residents of rural areas. Some parasitic zoonoses are confined to specific geographic areas in Egypt, such as cutaneous leishmaniasis and zoonotic babesiosis in the Sinai. Other areas have a past history of a certain parasitic zoonoses, such as visceral leishmaniasis in the El-Agamy area in Alexandria. As a result of the implementation of control programs, a marked decrease in the prevalence of other zoonoses, such as schistosomiasis and fascioliasis has been observed. Animal reservoirs of parasitic zoonoses have been identified in Egypt, especially in rodents, stray dogs and cats, as well as vectors, typically mosquitoes and ticks, which constitute potential risks for disease transmission. Prevention and control programs against sources and reservoirs of zoonoses should be planned by public health and veterinary officers based on reliable information from systematic surveillance.

Youssef, Ahmed I.; Uga, Shoji

2014-01-01

294

Proposed National Information Policy of Egypt.  

National Technical Information Service (NTIS)

A proposed statement of Egypt's national information policies is presented and some of the policies' implications for planning are discussed. The long-range purpose of these policies is to provide a motivation for generic courses of action conducive to th...

S. Adams M. A. K. Madkour V. Slamecka

1981-01-01

295

The practice of dentistry in ancient Egypt  

Microsoft Academic Search

This paper addresses the questions of whether a dental profession existed in ancient Egypt and if it did then considers whether these practitioners were operative dental surgeons as we know them today or whether they were pharmacists. Evidence from hieroglyphic inscriptions, from the dentitions of the surviving mummified and skeletal remains, and from ancient documents and artefacts are examined. The

R. J. Forshaw

2009-01-01

296

Women's "Justification" of Domestic Violence in Egypt  

ERIC Educational Resources Information Center

We explored the influences of women's social learning, marital resources and constraints, and exposure to norms about women's family roles on their views about wife hitting or beating among 5,450 participants in the 2005 Egypt Demographic and Health Survey. One half justified wife hitting or beating for some reason. Women from rural areas who were…

Yount, Kathryn M.; Li, Li

2009-01-01

297

English for Police Officers in Egypt.  

ERIC Educational Resources Information Center

Analyzes the use of English as a second language on the job by officers in several departments of the national police force in Egypt as determined by a survey of 150 officers. Suggests a syllabus for a common core course for all police officers, regardless of their specialization. (SED)

Mosallem, Elsayed Abo

1984-01-01

298

Genesis of the Hussainiyat ironstone deposit, Western Desert, Iraq  

Microsoft Academic Search

The Hussainiyat ironstone deposit (Jurassic) is mainly pisolitic, intraclastic and concretionary in texture, associated with\\u000a kaolinite mudstones and\\/or with quartzose sandstone. The ironstone consists mainly of goethite, hematite, kaolinite and quartz.\\u000a The deposits were derived from a variety of parent rocks that included low- and medium-rank metamorphics, intermediate igneous\\u000a rocks and pre-existing sediments of the Nubio-Arabian Shield. The source rocks

K. S. Al-Bassam; M. Y. Tamar-Agha

1998-01-01

299

Molecular subtype analysis determines the association of advanced breast cancer in Egypt with favorable biology  

PubMed Central

Background Prognostic markers and molecular breast cancer subtypes reflect underlying biological tumor behavior and are important for patient management. Compared to Western countries, women in North Africa are less likely to be prognosticated and treated based on well-characterized markers such as the estrogen receptor (ER), progesterone receptor (PR) and Her2. We conducted this study to determine the prevalence of breast cancer molecular subtypes in the North African country of Egypt as a measure of underlying biological characteristics driving tumor manifestations. Methods To determine molecular subtypes we characterized over 200 tumor specimens obtained from Egypt by performing ER, PR, Her2, CK5/6, EGFR and Ki67 immunohistochemistry. Results Our study demonstrated that the Luminal A subtype, associated with favorable prognosis, was found in nearly 45% of cases examined. However, the basal-like subtype, associated with poor prognosis, was found in 11% of cases. These findings are in sharp contrast to other parts of Africa in which the basal-like subtype is over-represented. Conclusions Egyptians appear to have favorable underlying biology, albeit having advanced disease at diagnosis. These data suggest that Egyptians would largely profit from early detection of their disease. Intervention at the public health level, including education on the benefits of early detection is necessary and would likely have tremendous impact on breast cancer outcome in Egypt.

2011-01-01

300

Distribution of desert varnish in Arizona  

NASA Technical Reports Server (NTRS)

Desert varnish is the dark coat of clay and ferromanganese oxides developed on exposed rock surfaces in arid regions. It forms from the accretion of material from windblown dust. The distribution of desert varnish was mapped in Arizona. It was discovered that desert varnish could be mapped on a regional scale. Well developed desert varnish is common on stable rock surfaces in areas having alkaline soils and less than about 25 cm of annual precipitation. Rock surfaces in areas having more than 40 cm of annual precipitation are generally devoid of desert varnish. An experiment was conducted with varnished desert pavement stone. The stones were broken in half and half was set on a roof in central Illinois from April until October. Removed from the alkaline desert environment, it only took seven months for the varnish to develop an eroded appearance. This experiment graphically illustrates the dependency of desert varnish on alkalinity. In this context, the zones of eroded desert varnish in Arizona indicate that the area of active desert varnish formation has fluctuated, expanding in drier times and contracting/eroding in wetter times.

Elvidge, Christopher D.

1989-01-01

301

Dynamics and Resilience of Desert Ecosystems under Changing Climate  

NASA Astrophysics Data System (ADS)

Ecological models have been used to probe the causes of spatial complexity and predict specific responses of desert ecosystems. However, many models have been limited in their focus: models of dynamics have been developed with no consideration of the inherent patchiness or patterns in the vegetation, or else models have been developed to generate patterns with no consideration of the dynamics. Models that attempt to address both pattern and dynamics have been qualitative and descriptive. Furthermore, if, as is commonly believed, both dynamics and patterns/patchiness are a function of resource (specifically water) limitation, then there has been little integration of this relationship into such models. Consequently, these models have limited utility for understanding resilience of desert ecosystems. Here we present an integrated approach to the observed patchiness and dynamics in desert vegetation that is based on a sound process-based understanding and is formulated to accommodate previous conceptual models within an overarching framework. This framework is implemented as a mathematical model. Our contribution represents an advance over previous work in that we propose a general model framework for the analysis of ecosystem change in deserts that explicitly considers spatial interactions among multiple vegetation types and multiple resources, and predict specific responses to a variety of endogenous and exogenous disturbances. We present an application of this model to investigate conditions the conditions that would result in observed desert vegetation patterns in south-western desert systems of North America. In particular, we investigate the encroachment of shrubs (Larrea tridentata) into formerly pure stands of grass (Bouteloua eriopoda). We present the results of simulations that rest on rainfall data that was reconstructed for the Jornada Basin Long-Term Ecological Research site in southern New Mexico, USA based on 300-year tree- ring records. The results show that populations of native grasslands were stable under all historical rainfall conditions and should have remained stable over the last century. The observed encroachment of shrubs can only be explained by the combination of periodic droughts with a second disturbance, which in this work is simulated as varying grazing intensities. We also show that the spatial pattern of the invading species is a function of the behaviour of the previously dominant species in redistributing resource and propagules during times of resource stress.

Stewart, J.; Wainwright, J.; Parsons, A. J.; Okin, G. S.; Bestelmeyer, B.; Fredrickson, E. L.; Schlesinger, W. H.

2008-12-01

302

Spectral reflectance of biogenic crust developed on desert dune sand along the Israel-Egypt border  

Microsoft Academic Search

The effect of biogenic crust on imagery acquired by spaceborne sensors is demonstrated. The crust consists mostly of microphytes such as cyanobacteria. The macrophytes (higher vegetation) on the sand dunes are sparse and have a relatively low spectra! reflectance response. However, since a considerable ponton of the ground is covered by this biogenic crust, (which has a different spectral reflectance

A. Karnieli; H. Tsoar

1995-01-01

303

Uranium mineralization in the two mica granite of gabal Ribdab area, South Eastern Desert, Egypt.  

PubMed

Among the different rock units in the Gabal Ribdab area, the two-mica leucogranite and muscovite pegmatitic granite are the most favourable host rocks for uranium and thorium mineralization. The muscovite pegmatitic granite shows evidence of post-magmatic alteration, e.g. Na- and K-metasomatism, whereas the two-mica leucogranite could be regarded as being fresh. The spectrometric survey revealed the presence of three enriched zones with a maximum eU content of 140 ppm and the maximum eTh is 36 ppm. Uranophane, zippeite and becquerelite are the most abundant uranium minerals. The origin of these secondary minerals is mainly related to alteration of primary minerals by the action of oxidizing fluids, mobilization of uranium and then redeposition in other forms. Redistribution by circulating meteoric waters might have taken place. PMID:11761111

Ibrahim, M E; Saleh, G M; Abd El-Naby, H H

2001-12-01

304

Geochemical reconnaissance survey and environmental assessment for stream sediments of Wadi Um Gier, Southeastern Desert, Egypt  

Microsoft Academic Search

The purposes of this study were to assess the influence of old mining activities on the geochemistry and quality of sediments\\u000a and to identify the sites of economic elements. Thirty sites of stream sediment were sampled in the study area covered by\\u000a granitic, metarhyodacitic and meta-andesitic rocks and related tuffs-hosted abandoned Au mine. The suite of chemical elements,\\u000a Ag, Bi,

Mohamed Abdallah Gad Darwish; Gad Darwish

2011-01-01

305

Basement structural control on Cretaceous pull-apart basins of the central Eastern Egypt Desert  

NASA Astrophysics Data System (ADS)

The present-day Red Sea / Gulf of Suez rift system is attributed to extensional block faulting with along-axis segmentation into sub-basins with different dip polarities. The northwestern margin of the Red Sea - Gulf of Suez rift system is exposed for about 400 km along the northwestern Red Sea coast near Quseir to the tip of the Gulf of Suez at Suez City. This area contains elements of the pre-Red Sea structural pattern which has been viewed in similar terms as one of fault-related basin formation. Four distinct depocenters (sub-basins) separated by complex accommodation zones are present containing 500-700m thick section ranging in age from the Late Cretaceous to the Middle Eocene. Each sub-basin is asymmetric, bounded on one side by a major NW-trending border fault system with large throws (3-6 km in general) with a dominant strata dip direction toward the border fault system. These basins are arranged in en echelon patterns and now form separate elongated ridges surrounded by basement rocks. Our study of the tectonic evolution of the central eastern section of the Gulf of Suez rift and the Northwestern Red Sea has focused on the interaction of pre-existing basement fabrics with the pre-Red Sea structural development. The study involved analysis of LandsatTM images and aerial photographs integrated with results from reconnaissance geological mapping. Our provisional results indicate that the Gebel Um Hammad/Duwi and Hammadat sub-basins were sited in pull-apart structures created by dextral reactivation of E-W to ENE-WSW trending basement fault zones. We show how the basin-bounding fault systems, lower order normal faults and folds in both hangingwall sequences and in basement are compatible with a Late Cretaceous to Early Eocene strike-slip regime. In contrast, the main Red Sea Gulf of Suez rift shows no evidence for strike-slip influence with the main boundary faults cutting across basement fabrics, however, as pointed out by previous authors, rift segmentation does appear to be basement-influenced.

McCaffrey, K.; El Kazzaz, Y.; Holdsworth, B.

2006-12-01

306

Prevalence of external parasites in the south eastern desert of Egypt.  

PubMed

External parasites in the triangle region (Halaib & Shalatin) affecting the animal health were studied. Ectoparasites were collected in several sites by using bait traps and directly from animal bodies. Results indicated the presence of twelve species of insects belonging to seven genera included in three families (Calliphoridae, Muscidae and Sarcophagidae). Concerning ectoparasites on animal bodies, there were two species of biting lice infested goats and sheep (Bovicola caprae and B. ovis, respectively) and two species of sucking lice on goats (Linognathus africanus and L. stenopsis). Melophagus ovinus (family Hippoboscidae) collected from goats. Moreover, all camels suffered infestation with hard ticks four Hyalomma species. On the other hand, sheep and goats were infested with two Rhipicephalus species and one Haemaphysalis species. PMID:12557945

el-Baky, S M

2001-04-01

307

Reference intervals and physiologic alterations in hematologic and biochemical values of free-ranging desert tortoises in the Mojave Desert.  

PubMed

Desert tortoise (Gopherus agassizii) populations have experienced precipitous declines resulting from the cumulative impact of habitat loss, and human and disease-related mortality. Evaluation of hematologic and biochemical responses of desert tortoises to physiologic and environmental factors can facilitate the assessment of stress and disease in tortoises and contribute to management decisions and population recovery. The goal of this study was to obtain and analyze clinical laboratory data from free-ranging desert tortoises at three sites in the Mojave Desert (California, USA) between October 1990 and October 1995, to establish reference intervals, and to develop guidelines for the interpretation of laboratory data under a variety of environmental and physiologic conditions. Body weight, carapace length, and venous blood samples for a complete blood count and clinical chemistry profile were obtained from 98 clinically healthy adult desert tortoises of both sexes at the Desert Tortoise Research Natural area (western Mojave), Goffs (eastern Mojave) and Ivanpah Valley (northeastern Mojave). Samples were obtained four times per year, in winter (February/March), spring (May/June), summer (July/August), and fall (October). Years of near-, above- and below-average rainfall were represented in the 5 yr period. Minimum, maximum and median values, and central 95 percentiles were used as reference intervals and measures of central tendency for tortoises at each site and/or season. Data were analyzed using repeated measures analysis of variance for significant (P < 0.01) variation on the basis of sex, site, season, and interactions between these variables. Significant sex differences were observed for packed cell volume, hemoglobin concentration, aspartate transaminase activity, and cholesterol, triglyceride, calcium, and phosphorus concentrations. Marked seasonal variation was observed in most parameters in conjunction with reproductive cycle, hibernation, or seasonal rainfall. Year-to-year differences and long-term alterations primarily reflected winter rainfall amounts. Site differences were minimal, and largely reflected geographic differences in precipitation patterns, such that results from these studies can be applied to other tortoise populations in environments with known rainfall and forage availability patterns. PMID:10231748

Christopher, M M; Berry, K H; Wallis, I R; Nagy, K A; Henen, B T; Peterson, C C

1999-04-01

308

Brief communication: Y-chromosome haplotypes in Egypt.  

PubMed

We analyzed Y-chromosome haplotypes in the Nile River Valley in Egypt in 274 unrelated males, using the p49a,f TaqI polymorphism. These individuals were born in three regions along the river: in Alexandria (the Delta and Lower Egypt), in Upper Egypt, and in Lower Nubia. Fifteen different p49a,f TaqI haplotypes are present in Egypt, the three most common being haplotype V (39.4%), haplotype XI (18.9%), and haplotype IV (13.9%). Haplotype V is a characteristic Arab haplotype, with a northern geographic distribution in Egypt in the Nile River Valley. Haplotype IV, characteristic of sub-Saharan populations, shows a southern geographic distribution in Egypt. PMID:12687584

Lucotte, G; Mercier, G

2003-05-01

309

Great Kavir Salt Desert, Iran  

NASA Technical Reports Server (NTRS)

Looking much like a piece of weathered wood, the Great Kavir Salt Desert (34.5N, 54.5E) of Iran illustrates the effects of wind erosion on the landscape. The region, known locally as the Dasht-e-Kavir, is about 300 kilometers southeast of Tehran, and typified by intricately folded sediments, that have been leveled by wind erosion to leave these beautiful and colorful formations.

1981-01-01

310

Clinicopathological features of melanocytic skin lesions in Egypt.  

PubMed

Although melanocytic skin lesions have been recognized since antiquity, their literature was limited to Caucasians. To date, the clinicopathologic features of these lesions in Egyptians are still unknown. To define these features, diagnostic records of the melanocytic skin lesions received at the Pathology Department, Assuit University Hospitals (1989-2004) were reviewed. The lesions examined included 12 benign naevi (BN), 10 dysplastic naevi (DN), and 21 cutaneous malignant melanomas (CMMs). The DN and CMMs were more common in men than in women (2 : 1 and 1.5 : 1, respectively) while BN were more common in women (2 : 1). The average age incidence was 33+/-5, 38+/-7 and 54+/-3 years, for BN, DN and CMM, respectively. The lower limb (13/21, 62%), head and neck (7/21, 33%) were the most common sites for CMMs. The average size (mm) was 2+/-0.3, 4+/-0.6 and 21+/-0.3 for BN, DN and CMMs, respectively. Recurrence occurred in 10% of CMMs. Histologically, CMMs were of nodular type and composed of epithelioid (7/21, 33%), spindle cells (1/21, 5%), or mixed cells (13/21, 62%). The mean tumour thickness (Breslow) was 6+/-0.5 mm. CMMs included two of 21(9%), three of 21(14%), six of 21(38%), and 10 of 21(38%) with Clark level II, III, IV and V. In Egypt, CMM is the third most common cutaneous neoplasm following squamous and basal cell carcinomas. Compared with Western societies, melanoma has a male sex predilection, similar histological features but different topographical distribution and rare incidence. The striking difference from Western series is the incidence of nodular melanoma - in the West this represents 15-30% of melanomas, with superficial spreading being the majority. Another key difference from the West is the 'sun-bed' culture of the West and the desire to have suntans. This is the first study that reports the clinicopathologic features of melanocytic skin lesions in Egypt. PMID:16374232

Hussein, Mahmoud R; Elsers, Dalia A; Fadel, Sabah A; Omar, Abd-Elhady M

2006-02-01

311

Unusual dominance by desert pupfish (Cyprinodon macularius) in experimental ponds within the Salton Sea Basin  

USGS Publications Warehouse

In October 2006, months after shallow experimental ponds in the Salton Sea Basin were filled with water from the Alamo River and Salton Sea, fish were observed in several ponds, although inlets had been screened to exclude fish. During October 2007November 2009, nine surveys were conducted using baited minnow traps to document species and relative abundance of fish. Surveys yielded 3,620 fish representing five species. Desert pupfish (Cyprinodon macularius), the only native species encountered, was the most numerous and comprised >93% of the catch. Nonnative species included western mosquitofish (Gambusia affinis, 4.1%), sailfin molly (Poecilia latipinna, 2.8%), and tilapia (a mixture of hybrid Mozambique tilapia Oreochromis mossambicus ?? O. urolepis and redbelly tilapia Tilapia zillii, <0.1%). Dominance by desert pupfish, which persisted over our 2 years of study, was unusual because surveys conducted in nearby agricultural drains yielded relatively few desert pupfish.

Saiki, Michael K.; Martin, Barbara A.; Anderson, Thomas W.

2011-01-01

312

Desert star (Monoptilon bellioides) flowers in bloom.  

NSDL National Science Digital Library

Desert star (Monoptilon bellioides) flowers in bloom. Desert star is an annual plant that grows in very arid regions of the southwestern United States. Desert star and other desert annuals may delay germination of some of their seeds in a bet-hedging strategy that maximizes their chances of reproductive success in a variable environment. By producing a subset of dormant seeds, plants increase the odds that some seeds will germinate in a year with conditions (such as higher rainfall amount) favorable for growth and reproduction. This photograph originally appeared on the cover of Ecology (88:5) in May of 2007.

Venable, D. L.

2010-02-12

313

Recoverability and Vulnerability of Desert Ecosystems  

NSDL National Science Digital Library

USGS scientists are taking an interdisciplinary approach to understanding the physical and biological processes that influence the vulnerability of the desert ecosystem to disturbance and its ability to recover. They are studying historical information, conducting experimental studies on physical and biological processes, and mapping and modeling the existing landscape. These data can be synthesized into maps and predictive models that show how ecosystem components respond to imposed stress, providing valuable tools for desert land managers. Such tools will help land managers make decisions that sustain the desert even as economic, recreation, and military uses continue. The site includes links to publications, maps, a glossary and links to other materials on Mojave desert ecosystems.

314

Management of Disused Radioactive Sealed Sources in Egypt - 13512  

SciTech Connect

The future safe development of nuclear energy and progressive increasing use of sealed sources in medicine, research, industry and other fields in Egypt depends on the safe and secure management of disused radioactive sealed sources. In the past years have determined the necessity to formulate and apply the integrated management program for radioactive sealed sources to assure harmless and ecological rational management of disused sealed sources in Egypt. The waste management system in Egypt comprises operational and regulatory capabilities. Both of these activities are performed under legislations. The Hot Laboratories and Waste Management Center HLWMC, is considered as a centralized radioactive waste management facility in Egypt by law 7/2010. (authors)

Mohamed, Y.T.; Hasan, M.A.; Lasheen, Y.F. [Hot Laboratories and Waste Management Center, Egyptian Atomic Energy Authority, 11787, Cairo (Egypt)] [Hot Laboratories and Waste Management Center, Egyptian Atomic Energy Authority, 11787, Cairo (Egypt)

2013-07-01

315

Sea Breezes over the Red Sea: Affect of topography and interaction with Desert Convective Boundary Layer  

NASA Astrophysics Data System (ADS)

Thermodynamic structure of sea-breeze, its interaction with coastal mountains, desert plateau and desert convective boundary layer have been investigated in the middle region of the Red Sea around 25°N, at the Western coast of Saudi Arabia. Sea and land breeze is a common meteorological phenomenon in most of the coastal regions around the world. Sea-Breeze effects the local meteorology and cause changes in wind speed, direction, cloud cover and sometimes precipitation. The occurrence of sea-breeze, its intensity and landward propagation are important for wind energy resource assessment, load forecasting for existing wind farms, air pollution, marine and aviation applications. The thermally induced mesoscale circulation of sea breeze modifies the desert Planetary Boundary Layer (PBL) by forming Convective Internal Boundary Layer (CIBL), and propagates inland as a density current. The leading edge of the denser marine air rapidly moves inland undercutting the hot and dry desert air mass. The warm air lifts up along the frontal boundary and if contains enough moisture a band of clouds is formed along the sea breeze front (SBF). This study focuses on the thermodynamic structure of sea-breeze as it propagates over coastal rocky mountain range of Al-Sarawat, east of the Red Sea coast, and the desert plateau across the mountain range. Additional effects of topographical gaps such as Tokar gap on the dynamics of sea-land breezes have also been discussed. Interaction of SBF with the desert convective boundary layer provide extra lifting that could further enhance the convective instability along the frontal boundary. This study provides a detailed analysis of the thermodynamics of interaction of the SBF and convective internal boundary layer over the desert. Observational data from a buoy and meteorological stations have been utilized while The Advanced Research WRF (ARW) modeling system has been employed in real and 2D idealized configuration.

Khan, Basit A.; Stenchikov, Georgiy; Abualnaja, Yasser

2014-05-01

316

Anthropogenic enhancement of Egypt's Mediterranean fishery  

PubMed Central

The highly productive coastal Mediterranean fishery off the Nile River delta collapsed after the completion of the Aswan High Dam in 1965. But the fishery has been recovering dramatically since the mid-1980s, coincident with large increases in fertilizer application and sewage discharge in Egypt. We use stable isotopes of nitrogen (?15N) to demonstrate that 60%–100% of the current fishery production may be from primary production stimulated by nutrients from fertilizer and sewage runoff. Although the establishment of the dam put Egypt in an ideal position to observe the impact of rapid increases in nutrient loading on coastal productivity in an extremely oligotrophic sea, the Egyptian situation is not unique. Such anthropogenically enhanced fisheries also may occur along the northern rim of the Mediterranean and offshore of some rapidly developing tropical countries, where nutrient concentrations in the coastal waters were previously very low.

Oczkowski, Autumn J.; Nixon, Scott W.; Granger, Stephen L.; El-Sayed, Abdel-Fattah M.; McKinney, Richard A.

2009-01-01

317

Anthropogenic enhancement of Egypt's Mediterranean fishery.  

PubMed

The highly productive coastal Mediterranean fishery off the Nile River delta collapsed after the completion of the Aswan High Dam in 1965. But the fishery has been recovering dramatically since the mid-1980s, coincident with large increases in fertilizer application and sewage discharge in Egypt. We use stable isotopes of nitrogen (delta(15)N) to demonstrate that 60%-100% of the current fishery production may be from primary production stimulated by nutrients from fertilizer and sewage runoff. Although the establishment of the dam put Egypt in an ideal position to observe the impact of rapid increases in nutrient loading on coastal productivity in an extremely oligotrophic sea, the Egyptian situation is not unique. Such anthropogenically enhanced fisheries also may occur along the northern rim of the Mediterranean and offshore of some rapidly developing tropical countries, where nutrient concentrations in the coastal waters were previously very low. PMID:19164510

Oczkowski, Autumn J; Nixon, Scott W; Granger, Stephen L; El-Sayed, Abdel-Fattah M; McKinney, Richard A

2009-02-01

318

Benchmarking performance: Environmental impact statements in Egypt  

SciTech Connect

Environmental impact assessment (EIA) was formally introduced in Egypt in 1994. This short paper evaluates 'how well' the EIA process is working in practice in Egypt, by reviewing the quality of 45 environmental impact statements (EISs) produced between 2000 and 2007 for a variety of project types. The Lee and Colley review package was used to assess the quality of the selected EISs. About 69% of the EISs sampled were found to be of a satisfactory quality. An assessment of the performance of different elements of the EIA process indicates that descriptive tasks tend to be performed better than scientific tasks. The quality of core elements of EIA (e.g., impact prediction, significance evaluation, scoping and consideration of alternatives) appears to be particularly problematic. Variables that influence the quality of EISs are identified and a number of broad recommendations are made for improving the effectiveness of the EIA system.

Badr, El-Sayed A., E-mail: ebadr@mans.edu.e [Environmental Sciences Department, Faculty of Science at Damietta, Mansoura University, New Damietta City, PO Box 103 (Egypt); Zahran, Ashraf A., E-mail: ashraf_zahran@yahoo.co [Environmental Studies and Research Institute, Minufiya University, Sadat City, Sixth Zone, PO 32897 (Egypt); Cashmore, Matthew, E-mail: m.cashmore@uea.ac.u [InteREAM, School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ (United Kingdom)

2011-04-15

319

Characterization of the Sonoran desert as a radiometric calibration target for Earth observing sensors  

USGS Publications Warehouse

To provide highly accurate quantitative measurements of the Earth's surface, a comprehensive calibration and validation of the satellite sensors is required. The NASA Moderate Resolution Imaging Spectroradiometer (MODIS) Characterization Support Team, in collaboration with United States Geological Survey, Earth Resources Observation and Science Center, has previously demonstrated the use of African desert sites to monitor the long-term calibration stability of Terra MODIS and Landsat 7 (L7) Enhanced Thematic Mapper plus (ETM+). The current study focuses on evaluating the suitability of the Sonoran Desert test site for post-launch long-term radiometric calibration as well as cross-calibration purposes. Due to the lack of historical and on-going in situ ground measurements, the Sonoran Desert is not usually used for absolute calibration. An in-depth evaluation (spatial, temporal, and spectral stability) of this site using well calibrated L7 ETM+ measurements and local climatology data has been performed. The Sonoran Desert site produced spatial variability of about 3 to 5% in the reflective solar regions, and the temporal variations of the site after correction for view-geometry impacts were generally around 3%. The results demonstrate that, barring the impacts due to occasional precipitation, the Sonoran Desert site can be effectively used for cross-calibration and long-term stability monitoring of satellite sensors, thus, providing a good test site in the western hemisphere.

Angal, Amit; Chander, Gyanesh; Xiong, Xiaoxiong; Choi, Taeyoung; Wu, Aisheng

2011-01-01

320

MERS Coronaviruses in Dromedary Camels, Egypt  

PubMed Central

We identified the near-full-genome sequence (29,908 nt, >99%) of Middle East respiratory syndrome coronavirus (MERS-CoV) from a nasal swab specimen from a dromedary camel in Egypt. We found that viruses genetically very similar to human MERS-CoV are infecting dromedaries beyond the Arabian Peninsula, where human MERS-CoV infections have not yet been detected.

Chu, Daniel K.W.; Poon, Leo L.M.; Gomaa, Mokhtar M.; Shehata, Mahmoud M.; Perera, Ranawaka A.P.M.; Abu Zeid, Dina; El Rifay, Amira S.; Siu, Lewis Y.; Guan, Yi; Webby, Richard J.; Ali, Mohamed A.

2014-01-01

321

Pediatric eye injuries in upper Egypt  

PubMed Central

Purpose To analyze the patterns, causes, and outcome of pediatric ocular trauma at Assiut University Hospital in Upper Egypt (South of Egypt). Methods All ocular trauma patients aged 16 years or younger admitted to the emergency unit of Ophthalmology Department of Assiut University between July 2009 and July 2010 were included in the study. The demographic data of all patients and characteristics of the injury events were determined. The initial visual acuity and final visual acuity after 3 months follow-up were recorded. Results One hundred and fifty patients were included. The majority of injuries occurred in children aged 2–7 years (50.7%). There were 106 (70.7%) boys and 44 (29.3%) girls. The highest proportion of injuries occurred in the street (54.7%) followed by the home (32.7%). Open globe injuries accounted for 67.3% of injuries, closed globe for 30.7%, and chemical injuries for 2%. The most common causes were wood, stones, missiles, and glass. LogMar best corrected visual acuity at 3 months follow-up was: 0–1 in 13.3%; <1–1.3 in 27.3%; <1.3–perception of light (PL) in 56%; and no perception of light (NPL) in 3.3%. Conclusions Pediatric ocular trauma among patients referred to our tertiary ophthalmology referral center in Upper Egypt over a period of 1 year was 3.7%. Of these, 67.3% of cases had open globe injury, 30.7% had closed injury, and only 2% had chemical injury. In Upper Egypt, socioeconomic and sociocultural status, family negligence, and lack of supervision are important factors in pediatric eye injuries, as 92% of children were without adult supervision when the ocular trauma occurred. Nearly 86.6% of children with ocular trauma end up legally blind. Modification of these environmental risk factors is needed to decrease pediatric ocular morbidity.

El-Sebaity, Dalia M; Soliman, Wael; Soliman, Asmaa MA; Fathalla, Ahmed M

2011-01-01

322

MERS Coronaviruses in Dromedary Camels, Egypt.  

PubMed

We identified the near-full-genome sequence (29,908 nt, >99%) of Middle East respiratory syndrome coronavirus (MERS-CoV) from a nasal swab specimen from a dromedary camel in Egypt. We found that viruses genetically very similar to human MERS-CoV are infecting dromedaries beyond the Arabian Peninsula, where human MERS-CoV infections have not yet been detected. PMID:24856660

Chu, Daniel K W; Poon, Leo L M; Gomaa, Mokhtar M; Shehata, Mahmoud M; Perera, Ranawaka A P M; Abu Zeid, Dina; El Rifay, Amira S; Siu, Lewis Y; Guan, Yi; Webby, Richard J; Ali, Mohamed A; Peiris, Malik; Kayali, Ghazi

2014-06-01

323

Dynamics of the South American Coastal Desert  

Microsoft Academic Search

The world's driest coastal desert is in South America along the coasts of Peru and Chile. The desert's maintenance is investigated by studying the local dynamics of the low-level southerly flow along the coast. A linear boundary-layer model is used in which a Boussinesq atmosphere is driven by a surface thermal contrast on a plane. The resting basic state is

Magda Luzimar de Abreu; Peter R. Bannon

1993-01-01

324

Notes from the Great American Desert  

ERIC Educational Resources Information Center

In the good old days, the state that is Nebraska was identified as part of the Great American Desert. In many ways, in climate and terrain, it still bears a resemblance to a desert. As a frontier or a land of pioneers, it deserves recognition. Invisibility may be one of the greatest challenges women face. One of the great flaws in the writing of…

Grady, Marilyn L.; LaCost, Barbara Y.

2005-01-01

325

On carbon sequestration in desert ecosystems  

USGS Publications Warehouse

Recent reports of net ecosysytem production >100 g C m-2 yr-1 in deserts are incompatible with existing measurements of net primary production and carbon pools in deserts. The comparisions suggest that gas exchange measurements should be used with caution and better validation if they are expected to indicate the magnitude of carbon sink in these ecosysytems. ?? 2009 Blackwell Publishing.

Schlesinger, W. H.; Belnap, J.; Marion, G.

2009-01-01

326

Being Logical About Desert Island Reading  

Microsoft Academic Search

To begin with, I refuse to be stranded on a desert island: sand without vegetation, hot sun, and salty water are just not conducive to good thinking. So let’s get into deserted tropical island mood, which is what everyone else has been doing. First, let’s wind time back to around 1978. This is important because our bodies can do without

Alex Borgida

2002-01-01

327

Magnetic Analysis Techniques Applied to Desert Varnish  

NASA Technical Reports Server (NTRS)

Desert varnish is a black or reddish coating commonly found on rock samples from arid regions. Typically, the coating is very thin, less than half a millimeter thick. Previous research has shown that the primary components of desert varnish are silicon oxide clay minerals (60%), manganese and iron oxides (20-30%), and trace amounts of other compounds [1]. Desert varnish is thought to originate when windborne particles containing iron and manganese oxides are deposited onto rock surfaces where manganese oxidizing bacteria concentrate the manganese and form the varnish [4,5]. If desert varnish is indeed biogenic, then the presence of desert varnish on rock surfaces could serve as a biomarker, indicating the presence of microorganisms. This idea has considerable appeal, especially for Martian exploration [6]. Magnetic analysis techniques have not been extensively applied to desert varnish. The only previous magnetic study reported that based on room temperature demagnetization experiments, there were noticeable differences in magnetic properties between a sample of desert varnish and the substrate sandstone [7]. Based upon the results of the demagnetization experiments, the authors concluded that the primary magnetic component of desert varnish was either magnetite (Fe3O4) or maghemite ( Fe2O3).

Schmidgall, E. R.; Moskowitz, B. M.; Dahlberg, E. D.; Kuhlman, K. R.

2003-01-01

328

African Refugees in Egypt: Trauma, Loss, and Cultural Adjustment  

Microsoft Academic Search

This study examined the influence of pre-immigration trauma on the acculturation process of refugees, as reflected in the manifestations of their continuing bonds with native cultures. Six African refugees who sought refuge in Egypt because of wars and political persecution were interviewed about the circumstances of their departure from their home countries, as well as their life experiences in Egypt.

Hani M. Henry

2012-01-01

329

WIND ATLAS FOR EGYPT: MEASUREMENTS, MICRO AND MESOSCALE MODELLING  

Microsoft Academic Search

The results of a comprehensive, 8-year wind resource assessment programme in Egypt are presented. The objective has been to provide reliable and accurate wind atlas data sets for evaluating the potential wind power output from large electricity-producing wind turbine installations. The regional wind climates of Egypt have been determined by two independent methods: a traditional wind atlas based on observations

Niels G. Mortensen; Jens Carsten Hansen; Jake Badger; Bo H. Jørgensen; Charlotte B. Hasager; Uwe S. Paulsen; Ole F. Hansen; Karen Enevoldsen

330

Surveillance for Rift Valley Fever in Egypt During 1983.  

National Technical Information Service (NTIS)

In 1977, Egypt experienced its first recorded outbreak of Rift Valley Fever (RVF). Since the last isolation of RVF virus in 1981, continued transmission of RVF in Egypt has been disputed. A surveillance system was established by NAMRU-3 in 1982 using acce...

B. A. Botros P. W. Mellick A. W. Salib A. K. Soliman M. T. Dalam

1985-01-01

331

Resource Unit on Egypt for the Intermediate Grades.  

ERIC Educational Resources Information Center

Resources for teaching about modern and ancient Egypt are provided in this guide for intermediate grade social studies teachers. Material includes: a detailed outline for a unit on Egypt which contains a geographic overview followed by sections on the Nile River Valley, agriculture, the pharaohs, religion, architecture, science, hieroglyphics,…

Husbands, Kenneth; Taylor, Bob

332

Religious Literature of Late Period and Greco-Roman Egypt  

Microsoft Academic Search

Although Egypt was ruled by foreigners during most of the Late and Greco-Roman periods, native religious traditions remained strong and the period witnessed the production of a wide variety of religious texts written in the Egyptian language. This article presents many of the major religious texts of Egypt's Late and Greco-Roman periods and comments on the trends of continuity and

Jacqueline E. Jay

2007-01-01

333

Enabling Entrepreneurship in Egypt: Toward a Sustainable Dynamic Model  

Microsoft Academic Search

The objective of this report is to assess the current status of entrepreneurship in Egypt, and to offer strategic and actionable recommendations that will enable entrepreneurship and significantly impact the Egyptian economy. The report offers a fresh look at entrepreneurship in Egypt and the support mechanisms currently at play, assesses the initiatives and challenges at hand, and provides multilevel recommendations

Mohamed El Dahshan; Ahmed H. Tolba; Tamer Badreldin

2012-01-01

334

Feasibility Study on the Tinplate Manufacturing Facility, General Lithograph Egypt Company, Cario Egypt.  

National Technical Information Service (NTIS)

This report, conducted by UEC, was funded by the U.S. Trade and Development Agency. It examines the feasibility of constructing a tinplate manufacturing facility in Egypt. The report contains information on a market survey, a facility plan, a capital esti...

2000-01-01

335

First Ladies' Symposium on Early Childhood in Egypt (Cairo, Egypt, May 21, 2001).  

ERIC Educational Resources Information Center

This document is comprised of the papers presented at the First Ladies' Symposium on Early Childhood in Egypt in May 2001. Participating in the symposium were representatives from the World Bank, the Amsterdam Institute for International Development, the Children's Project, and the Academy for Educational Development. The symposium opened with an…

O'Gara, Chloe

336

Isolation of biologically active constituents from Moringa peregrina (Forssk.) Fiori. (family: Moringaceae) growing in Egypt  

PubMed Central

Background: Moringa peregrina is a wild plant that grown in the eastern desert mountains in Egypt. Although, this plant is native to Egypt, no details studies were traced on its chemical composition and biological activity. Materials and Methods: The different fractions of the ethanolic extract of the dried aerial parts of the plants were subjected to fractionation and purification on various silica and sephadex columns for the isolation of the major compounds which were tested for there anticancer activity. The aqueous and ethanolic extract as well as its different fractions were tested for antihyperglycemic effect on Streptozitocin-induced diabetes in rats. Results: Investigation of the different fractions of the ethanolic extract of the aerial parts of M. peregrina yielded lupeol acetate (1), ?-amyrin (2), ?-amyrin (3), ?-sitosterol (4), ?-sitosterol-3-O-glucoside (5), apigenin (6), rhamnetin (7), neochlorogenic acid (10), rhamnetin-3-O-rutinoside (12), and 6-methoxy-acacetin-8-C-?-glucoside (13) which were isolated for the first time from the plant. Compound (13) was isolated for the first time from genus Moringa. In addition, quercetin (8), chryseriol-7-O-rhamnoside (9) and quercetin-3-O-rutinoside (11) were also isolated. Identification has been established by spectral data (UV, MS, IR, 1H, 1H -1H COSY, and 13C-NMR). The major isolated compounds were found to have valuable cytotoxic activities against breast (MCF 7) and colon (HCT 116) cancer cell lines and their activities were comparable to the reference drug doxorubicin. On the other hand, the aqueous and ethanolic extracts as well as the n-hexane fraction were found to have potent antihyperglycemic effect on Streptozitocin-induced diabetes in rats. Conclusion: The Egyptian plant M. peregrina is rich in biologically active ingredients which showed potent cytotoxic activity and also its ethanolic extraxt exert a significant antihyperglycemic effect.

El-Alfy, Taha S.; Ezzat, Shahira M.; Hegazy, Ahmed K.; Amer, Aziza M. M.; Kamel, Gehan M.

2011-01-01

337

Effects of desert wildfires on desert tortoise (Gopherus agassizii) and other small vertebrates  

USGS Publications Warehouse

We report the results of standardized surveys to determine the effects of wildfires on desert tortoises (Gopherus agassizii) and their habitats in the northeastern Mojave Desert and northeastern Sonoran Desert. Portions of 6 burned areas (118 to 1,750 ha) were examined for signs of mortality of vertebrates. Direct effects of fire in desert habitats included animal mortality and loss of vegetation cover. A range of 0 to 7 tortoises was encountered during surveys, and live tortoises were found on all transects. In addition to desert tortoises, only small (<1 kg) mammals and reptiles (11 taxa) were found dead on the study areas. We hypothesize that indirect effects of fire on desert habitats might result in changes in the composition of diets and loss of vegetation cover, resulting in an increase in predation and loss of protection from temperature extremes. These changes in habitat also might cause changes in vertebrate communities in burned areas.

Esque, T. C.; Schwalbe, C. R.; Defalco, L. A.; Duncan, R. B.; Hughes, T. J.

2003-01-01

338

Libyan Desert Glass: New field and Fourier transform infrared data  

NASA Astrophysics Data System (ADS)

Results are presented of new geological observations and laboratory analyses on Libyan Desert Glass (LDG), a unique kind of impact glass found in Egypt, probably 28.5-29.4 million years in age. A new LDG occurrence has been discovered some 50 km southward of the main LDG occurrences in the Great Sand Sea. From Fourier transform infrared (FTIR) analysis, the molecular structure of LDG is refined and significant differences are shown between LDG specimens and other pure silica glasses (fulgurite, industrial fused quartz, and amorphous biogenic silica) that are related to differences in their structures. The slight variations observed here for the mean Si-O-Si angle between the different glasses are attributed to their thermal histories. With regard to the other glasses analyzed, the LDG infrared spectral parameters point to a higher ratio of discontinuities and defects in the tetrahedral (SiO4) network. The quantitative mineralogical constitutions of sandstones and quartzites from the LDG geological setting were analyzed by FTIR. Cretaceous sandstones have a specific composition (about 90 wt% quartz, 10% dickite), clearly different from the Paleozoic ones (about 90 wt% quartz, but ?7% kaolinite). It is shown that the reddish silts bearing the LDG are constituted mainly of microquartz enriched with dickite, whose particle size distribution is characteristic of fluvio-lacustrine deposits, probably Oligocene to Miocene in age. The target rocks, most probably quartz sand, resulted from the weathering (loss of the cementing microquartz) of the Cretaceous sandstones from the Gilf Khebir Plateau with deposition in a high-energy environment.

Fröhlich, F.; Poupeau, G.; Badou, A.; Le Bourdonnec, F. X.; Sacquin, Y.; Dubernet, S.; Bardintzeff, J. M.; Véran, M.; Smith, D. C.; Diemer, E.

2013-12-01

339

Water use, productivity and interactions among desert plants. Final report  

SciTech Connect

On the Colorado Plateau, precipitation comes either from winter storms generated in the Gulf of Alaska or from summer convection storms generated by the Arizona monsoon system. Understanding the current seasonal and regional patterns of precipitation inputs into an ecosystem has ramifications at several levels: on carbon and mineral cycling at the ecosystem level, on biodiversity at the community level, and on productivity and adaptation at the population and species levels. The interior deserts of Arizona, Nevada, and Utah represent the driest regions of western North America, resulting from a combination of rainshadow effects and either the southern limits of winter moisture input or the northern limits of summer moisture input or both. Shifts in strengths of storm-generating conditions in the Pacific and in the Gulf influence both the magnitude and seasonality of soil moisture availability and therefore constrain periods of primary productivity activity in these aridland ecosystems. One major consequence predicted by global climate change scenarios is a change in monsoonal (summer) precipitation; it will increase in some areas and decrease in others. A second is increased soil temperatures and increased interior drought associated with ocean-land temperature disequilibrium. This project focused on the influence of variations in summer moisture input on structure-function relationships within a cold desert ecosystem on the Colorado Plateau. The primary field sites were located at Stud Horse Point, Utah, located on the Utah-Arizona boundary in the Glen Canyon National Recreation Area and at the Arizona monsoon boundary region.

Ehleringer, J.R.

1996-09-01

340

Stranded on a Desert Island  

NSDL National Science Digital Library

In this activity, learners are stranded on a tropical desert island. At an abandoned science lab on the island, they explore the properties of different materials to determine which are best to construct a shelter, boat, and path to aid in their survival. The properties investigated are: magnetism, conductivity, opacity, buoyancy, and elasticity. Learners practice research techniques, must work together, and need to design within constraints. This lesson plan includes definitions of key words, scenario sheet, lab sheets,and handouts. This activity is the third in a four part series of pre/post activities (Matter, Matter, What's the Matter?) created for an exhibit on material science, but can be used on its own.

Houston, Children'S M.

2009-01-01

341

Multiroute memories in desert ants  

PubMed Central

When offered a permanent food source, central Australian desert ants, Melophorus bagoti, develop individually distinct, view-based foraging routes, which they retrace with amazing accuracy during each foraging trip. Using a particular channel setup connected to an artificial feeder, we trained M. bagoti ants to either two or three inward routes that led through different parts of their maze-like foraging grounds. Here, we show that ants are able to adopt multiple habitual paths in succession and that they preserve initially acquired route memories even after they have been trained to new routes. Individual ants differ in the consistency with which they run along habitual pathways. However, those ants that follow constant paths retain their route-specific memories for at least 5 days of suspended foraging, which suggests that even multiple route memories, once acquired, are preserved over the entire lifetime of a forager.

Sommer, Stefan; von Beeren, Christoph; Wehner, Rudiger

2008-01-01

342

Desert Dust and Monsoon Rain  

NASA Technical Reports Server (NTRS)

For centuries, inhabitants of the Indian subcontinent have know that heavy dust events brought on by strong winds occur frequently in the pre-monsoon season, before the onset of heavy rain. Yet scientists have never seriously considered the possibility that natural dust can affect monsoon rainfall. Up to now, most studies of the impacts of aerosols on Indian monsoon rainfall have focused on anthropogenic aerosols in the context of climate change. However, a few recent studies have show that aerosols from antropogenic and natural sources over the Indian subcontinent may affect the transition from break to active monsoon phases on short timescales of days to weeks. Writing in Nature Geoscience, Vinoj and colleagues describe how they have shown that desert dust aerosols over the Arabian Sea and West Asia can strenghten the summer monsoon over the Indial subcontinent in a matter of days.

Lau, William K. M.; Kim, Kyu-Myong

2014-01-01

343

Desert Dust Satellite Retrieval Intercomparison  

NASA Technical Reports Server (NTRS)

This work provides a comparison of satellite retrievals of Saharan desert dust aerosol optical depth (AOD) during a strong dust event through March 2006. In this event, a large dust plume was transported over desert, vegetated, and ocean surfaces. The aim is to identify and understand the differences between current algorithms, and hence improve future retrieval algorithms. The satellite instruments considered are AATSR, AIRS, MERIS, MISR, MODIS, OMI, POLDER, and SEVIRI. An interesting aspect is that the different algorithms make use of different instrument characteristics to obtain retrievals over bright surfaces. These include multi-angle approaches (MISR, AATSR), polarisation measurements (POLDER), single-view approaches using solar wavelengths (OMI, MODIS), and the thermal infrared spectral region (SEVIRI, AIRS). Differences between instruments, together with the comparison of different retrieval algorithms applied to measurements from the same instrument, provide a unique insight into the performance and characteristics of the various techniques employed. As well as the intercomparison between different satellite products, the AODs have also been compared to co-located AERONET data. Despite the fact that the agreement between satellite and AERONET AODs is reasonably good for all of the datasets, there are significant differences between them when compared to each other, especially over land. These differences are partially due to differences in the algorithms, such as as20 sumptions about aerosol model and surface properties. However, in this comparison of spatially and temporally averaged data, at least as significant as these differences are sampling issues related to the actual footprint of each instrument on the heterogeneous aerosol field, cloud identification and the quality control flags of each dataset.

Carboni, E.; Thomas, G. E.; Sayer, A. M.; Siddans, R.; Poulsen, C. A.; Grainger, R. G.; Ahn, C.; Antoine, D.; Bevan, S.; Braak, R.; Brindley, H.; DeSouza-Mchado, S.; Deuze, J. L.; Diner, D.; Ducos, F.; Grey, W.; Hsu, C.; Kalashnikova, O. V.; Kahn, R.; North, P. R. J.; Salustro, C.; Smith, A.; Tanre, D.; Torres, O.; Veihelmann, B.

2012-01-01

344

Satellite observations of desert dust-induced Himalayan snow darkening  

NASA Astrophysics Data System (ADS)

The optically thick aerosol layer along the southern edge of the Himalaya has been subject of several recent investigations relating to its radiative impacts on the South Asian summer monsoon and regional climate forcing. Prior to the onset of summer monsoon, mineral dust from southwest Asian deserts is transported over the Himalayan foothills on an annual basis. Episodic dust plumes are also advected over the Himalaya, visible as dust-laden snow surface in satellite imagery, particularly in western Himalaya. We examined spectral surface reflectance retrieved from spaceborne MODIS observations that show characteristic reduction in the visible wavelengths (0.47 µm) over western Himalaya, associated with dust-induced solar absorption. Case studies as well as seasonal variations of reflectance indicate a significant gradient across the visible (0.47 µm) to near-infrared (0.86 µm) spectrum (VIS-NIR), during premonsoon period. Enhanced absorption at shorter visible wavelengths and the resulting VIS-NIR gradient is consistent with model calculations of snow reflectance with dust impurity. While the role of black carbon in snow cannot be ruled out, our satellite-based analysis suggests the observed spectral reflectance gradient dominated by dust-induced solar absorption during premonsoon season. From an observational viewpoint, this study underscores the importance of mineral dust deposition toward darkening of the western Himalayan snow cover, with potential implications to accelerated seasonal snowmelt and regional snow albedo feedbacks.

Gautam, Ritesh; Hsu, N. Christina; Lau, William K.-M.; Yasunari, Teppei J.

2013-03-01

345

Desert R.A.T.S. 2011  

NASA Video Gallery

Desert Research And Technology Studies (D-R.A.T.S) kicks off an exciting new year of field testing. The crew is back in action, testing communication scenarios for near-Earth asteroids, and two new...

346

Sampling and handling of desert soils  

NASA Technical Reports Server (NTRS)

Report on sampling and handling desert soils includes sections on selection, characterization, and photography of area, site, and soil, sterilization of sampling equipment and containers, and soil sample collection, transport, storage, and dispersal.

Blank, G. B.; Cameron, R. E.

1969-01-01

347

Desert Pupfish ('Cyprinodon macularius') Recovery Plan.  

National Technical Information Service (NTIS)

The objective of this recovery action plan is to describe actions necessary to eliminate threats to extant populations and successfully establish additional populations of desert pupfish in secure habitats within probable historic range.

1993-01-01

348

2011 Desert RATS Sights and Sounds  

NASA Video Gallery

Watch scenes from the 2011 Desert Research and Technology Studies (RATS) analog field test, as NASA scientists and engineers drive the Space Exploration Vehicle, assemble equipment in the Habitat D...

349

Mojave sandy desert habitat in Summer (August)  

NSDL National Science Digital Library

An intense, dry summer from May through August has left the vegetation sun scorched and they no longer retain their healthy, green appearance. These shrubs are adapted to the desert and will go dormant after one season.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-06

350

Chapter 3: neurology in ancient Egypt.  

PubMed

Neurology, in the modern sense, did not exist in ancient Egypt, where medicine was a compound of natural, magical and religious elements, with different practitioners for each form of healing. Nevertheless, Egyptian doctors made careful observations of illness and injury, some of which involved the nervous system. Modern scholars have three sources of information about Egyptian medicine: papyri, inscriptions, and mummified remains. These tell us that the Egyptians had words for the skull, brain, vertebrae, spinal fluid and meninges, though they do not say if they assigned any function to them. They described unconsciousness, quadriparesis, hemiparesis and dementia. We can recognize neurological injuries, such as traumatic hemiparesis and cervical dislocation with paraplegia, in the well known Edwin Smith surgical papyrus. Similarly recognizable in the Ebers papyrus is a description of migraine. An inscription from the tomb of the vizier Weshptah, dated c. 2455 BCE, seems to describe stroke, and Herodotus describes epilepsy in Hellenistic Egypt. We have very little understanding of how Egyptian physicians organized these observations, but we may learn something of Egyptian culture by examining them. At the same time, modern physicians feel some connection to Egyptian physicians and can plausibly claim to be filling a similar societal role. PMID:19892106

York, George K; Steinberg, David A

2010-01-01

351

Roebuck Bay and the Town of Broome, Western Australia, Australia  

NASA Technical Reports Server (NTRS)

Roebuck Bay (18.0S, 122.0E) is a prominent bay on the arid northwest coast of Western Australia and the town of Broome is one of the few prominent towns along this very sparsley settled coast. The large gray area extending back from the shoreline of the bay is the Roebuck Plains slowly being filled with sediment by local streams draining the Great Sandy Desert. The irregular bare patches on the desert to the south are burn scars from brush fires.

1992-01-01

352

Impact of the Desert Dust on the Summer Monsoon System over Southwestern North America  

SciTech Connect

The radiative forcing of dust emitted from the Southwest United States (US) deserts and its impact on monsoon circulation and precipitation over the North America monsoon (NAM) region are simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem) for 15 years (1995-2009). During the monsoon season, dust has a cooling effect (-0.90 W m{sup -2}) at the surface, a warming effect (0.40 W m{sup -2}) in the atmosphere, and a negative top-of-the-atmosphere (TOA) forcing (-0.50 W m{sup -2}) over the deserts on 24-h average. Most of the dust emitted from the deserts concentrates below 800 hPa and accumulates over the western slope of the Rocky Mountains and Mexican Plateau. The absorption of shortwave radiation by dust heats the lower atmosphere by up to 0.5 K day{sup -1} over the western slope of the Mountains. Model sensitivity simulations with and without dust for 15 summers (June-July-August) show that dust heating of the lower atmosphere over the deserts strengthens the low-level southerly moisture fluxes on both sides of the Sierra Madre Occidental. It also results in an eastward migration of NAM-driven moisture convergence over the western slope of the Mountains. These monsoonal circulation changes lead to a statistically significant increase of precipitation by up to {approx}40% over the eastern slope of the Mountains (Arizona-New Mexico-Texas regions). This study highlights the interaction between dust and the NAM system and motivates further investigation of possible dust feedback on monsoon precipitation under climate change and the megadrought conditions projected for the future.

Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.

2012-04-24

353

North American Desert Microbiotic Soil Crust Communities  

Microsoft Academic Search

Deserts are defined in a classic paper by Noy-Meir (1973) as “water-controlled ecosystems with infrequent, discrete, and largely\\u000a unpredictable water inputs.” They are found to a greater or lesser extent on all six continents (including Antarctica). Based\\u000a on the moisture index system of Thornthwaite (1948), Meigs (1953) divided deserts into three categories: extremely arid (less\\u000a than 60–100 mm mean annual

Valerie R. Flechtner

354

Geochemical registers of Late Quaternary paleoclimatic conditions at Sonora and Chihuahua Deserts, Mexico: comparison and synthesis  

NASA Astrophysics Data System (ADS)

Sonora and Chihuahua Deserts form the southwestern and southeastern parts of North American Desert system and spread over at least 5 different states in the northern Mexico. Presently, Sonora Desert receives annual precipitation in a bi-modal distribution, whereas Chihuahua Desert receives dominant summer precipitation. Paleoclimatic registers from Mojave Desert suggest that the spatial extent and magnitude of both the summer and winter precipitation varied during the last glacial period and such fluctuations were linked to the volume of the Laurentide ice sheet, changing winter-summer insolation, North Atlantic climatic variability and ENSO dynamics. We present multi-elemental concentrations, magnetic susceptibility, organic and inorganic carbon from 750 cm long sediment core collected from paleolake San Felipe (31°N, western Sonora Desert) and 970 cm long sediment core collected from paleolake Babicora (29°N, western Chihuahua Desert) in order to understand the paleohydrological and paleoclimatic evolution in the arid region of northern Mexico. 6 AMS 14C dates constrain the San Felipe sediment core between 49 cal kyr BP and present. Similarly, 8 AMS 14C dates put the Babicora core in the age bracket between 76 cal kyr BP and present with two different hiatus at 4-8 cal kyr BP and 40-45 cal kyr BP. Due to the special geomorphology of San Felipe basin, Ti concentration was used as a proxy for pluvial discharge and to differentiate regimes of dominant summer and winter precipitation. Aeolian deposition was constrained at >48 cal kyr BP. Period of lower pluvial discharge during 14-48 cal kyr BP is related to a regime of dominant winter frontal storms. During 3-14 cal kyr BP, higher catchment erosion and transportation of REE bearing heavy minerals into the basin are possibly as a result of higher pluvial discharge related to a regime of dominant summer precipitation. In paleolake Babicora, high resolution Ti suggests higher pluvial inflow prior to 60 cal kyr BP (H 6). Gradually decreasing pluvial discharge and increasing aeolian activities occurred during 45-60 cal kyr BP (H 5 to H 6) and corresponds to a warmer Greenland and higher solar activity. High amplitude fluctuations of pluvial discharge continued since Heinrich 4 and highest abundance of ostracode valves suggest alkaline conditions during 45-30 cal kyr BP and this lake desiccated periodically in the last 12 cal kyr BP.

Roy, P.; Perez-Cruz, L. L.; Lozano-Garcia, S.

2011-12-01

355

Genetic linkage between the Yellow River, the Mu Us desert and the Chinese Loess Plateau  

NASA Astrophysics Data System (ADS)

Arid and semi arid northern China holds some of the world's most significant sand sea and loess deposits. In particular, arguably the most important late Cenozoic wind-blown dust archives on land are exposed on the Chinese Loess Plateau. The origin of this loess-forming dust and its relationship to adjacent sand seas is unclear and has been the subject of considerable debate. Polarization of opinion over the sources of loess also reflects uncertainty over its relationship to large river systems and to the sources of proximal desert sands. It is critical to resolve this in order to elucidate the origins of sand seas, to determine the activity of past dust emitting regions and to fully exploit loess climate archives. Here we combine zircon U–Pb, fission-track and double dating with heavy mineral analysis to test the role of proximal deserts and rivers in contributing dust to the Loess Plateau. We focus on the Mu Us desert to test hypotheses over its sediment sources and because previous studies have often presented contrasting interpretations over its importance as a loess source. Spatial complexity of zircon ages and heavy mineral assemblages in Mu Us sand rules out significant aeolian mixing and shows that grains originating in northern Tibet dominate in the western Mu Us, with local sources dominating in the east of the desert. The western Mu Us far-travelled grains are shown to be delivered by the Yellow River and associated systems. Crucially, the western Mu Us grains and Yellow River grains show U–Pb age distributions and heavy mineral assemblages virtually identical to those of the Quaternary loess. Thus, our results demonstrate that the Yellow River and associated systems transports large quantities of sediment from northern Tibet to the Mu Us desert and further suggest that the river contributes a significant volume of material to the Loess Plateau. This provides the first evidence of a genetic link between the Yellow River and formation of the Chinese Loess Plateau and suggests a greater role for fluvial activity in past dust and desert sand sea formation.

Stevens, T.; Carter, A.; Watson, T. P.; Vermeesch, P.; Andò, S.; Bird, A. F.; Lu, H.; Garzanti, E.; Cottam, M. A.; Sevastjanova, I.

2013-10-01

356

Socioeconomic determinants of eating pattern of adolescent students in Mansoura, Egypt  

PubMed Central

Introduction During the last few decades, Egypt experienced rapid socio-cultural changes that were associated with major changes in the food choices and eating habits, which, progressively, becomes more westernized. The objective of this study was to investigate the meal patterns of secondary school adolescent students in Mansoura, Egypt. Methods This is a cross-sectional study conducted on 891 adolescent students. Thirty clusters were selected to cover both general and vocational public schools of both sexes in urban and rural areas. A self-administered questionnaire was used to collect data about sociodemographic features of the students and their families, as well as meal habits of students. Results About 46% of students eat three meals per day. About 72%, 93% and 95% of respondents consume breakfast, lunch and dinner on daily bases, respectively. Snacks were eaten daily by 34.1% of students. Eating always with the family was stated by the majority (62.5%) of students and taking home made sandwiches during school time was mentioned by 35.8% of students. On logistic regression socioeconomic status is the only predictor associated with daily intake of breakfast, lunch and dinner; with high likelihood of eating with the family and intake of school meal. Conclusion Students practice many faulty meal patterns. School-, family- and community-based interventions are timely needed to promote healthy eating habit in adolescents.

El-Gilany, Abdel-Hady; Elkhawaga, Ghada

2012-01-01

357

Crustal structure in southeastern Egypt: Symmetric thinning of the northern Red Sea rifted margins  

NASA Astrophysics Data System (ADS)

Crustal structure in southeastern Egypt has been investigated to elucidate the nature of crustal thinning across the northern Red Sea. P-wave receiver function modeling for seven stations in southeastern Egypt yields typical Proterozoic crustal thicknesses of 35-38 km around Lake Aswan, and thinner crust (25-26 km) within 50 km of the Red Sea coast. Vp/Vs ratios are on average 1.78 and indicate an intermediate composition crust. These results, when combined with other estimates of crustal thickness in the region, reveal a symmetric pattern of crustal thickness beneath the conjugate margins of the northern Red Sea. Such a pattern is consistent with a pure shear model of extension, and suggests that the greater amounts of uplift and volcanism on the eastern side of the Red Sea compared to the western side may be the result of deeper flow in the mantle associated with the African superplume and not directly a consequence of the rifting process.

Hosny, Ahmed; Nyblade, Andrew

2014-05-01

358

Environmental Assessment of the Egypt Screwworm Control Program.  

National Technical Information Service (NTIS)

The Environmental Assessment for the USAID-purchase of vehicles and other equipment for contingency New World Screwworm prevention listed herein, excluding pesticides, was performed in Egypt from May 6 - May 21, 1990, by the collaborative efforts of USAID...

1990-01-01

359

Alkhurma Hemorrhagic Fever in Travelers Returning from Egypt, 2010  

PubMed Central

Two travelers returning to Italy from southern Egypt were hospitalized with a fever of unknown origin. Test results showed infection with Alkhurma virus. The geographic distribution of this virus could be broader than previously thought.

Carletti, Fabrizio; Castilletti, Concetta; Di Caro, Antonino; Capobianchi, Maria R.; Nisii, Carla; Suter, Fredy; Rizzi, Marco; Tebaldi, Alessandra; Goglio, Antonio; Tosi, Cristiana Passerini

2010-01-01

360

Estimation of Recent Trends in Fertility and Mortality in Egypt.  

National Technical Information Service (NTIS)

This report provides a detailed review of mortality and fertility in Egypt from 1927 to 1979. After presenting background socioeconomic information, the authors outline changes in fertility and mortality since 1927 discuss sources of demographic data in E...

G. Askar A. J. Coale M. Desouki M. El-Badry M. H. El Guindy

1982-01-01

361

Flavonoids of Cynara scolymus L. cultivated in Egypt  

Microsoft Academic Search

The study of the flavonoids of the leaves ofCynara scolymus cultivated in Egypt (Romanian strain) resulted in the isolation and identification of apigenin-7-O-glucoside, luteolin, cynaroside and scolymoside.

F. M. Hammouda; M. M. Seif El-Nasr; A. A. Shahat

1993-01-01

362

Logistics Management Systems in Desert Shield/Desert Storm: How Well Did They Do.  

National Technical Information Service (NTIS)

Desert Shield/Desert Storm was a resounding logistical success. Record am personnel and tonnage were moved across record distances in record times. This is an effort truly worthy of praise. It is also a effort worthy of close review and analysis. This pap...

G. R. Gustafson

1992-01-01

363

HIGH FOLIAR NITROGEN IN DESERT SHRUBS: AN IMPORTANT ECOSYSTEM TRAIT OR DEFECTIVE DESERT DOCTRINE?  

EPA Science Inventory

Nitrogen concentrations in green and senesced leaves of perennial desert shrubs were compiled from a worldwide literature search to test the validity of the doctrine that desert shrubs produce foliage and leaf litter much richer in nitrogen than that in the foliage of plants from...

364

Internal and External Adaptation in Army Families: Lessons from Operations Desert Shield and Desert Storm  

ERIC Educational Resources Information Center

This study examined 1,064 Army families reunited after a member's deployment for Operation Desert Shield and Operation Desert Storm. Postdeployment outcomes were conceptualized in terms of the "fit" between the family and the demands of Army life, especially the stress of deployment. A structural model was used to test the hypothesized effects of…

Pittman, Joe F.; Kerpelman, Jennifer L.; McFadyen, Jennifer M.

2004-01-01

365

The rural and the rotund? A critical interpretation of food deserts and rural adolescent obesity in the Canadian context.  

PubMed

Resting on the notion that rural spaces are "food deserts," rural adolescents are increasingly regarded as a "problem population" in Western obesity narratives. Using qualitative data gleaned from interviews with 51 teenage participants from rural areas across Canada, this paper focuses on the ways in which obesity is constructed as a rural disease in the Canadian context, demonstrating in particular how discourses of food deserts and related rural obesity rely on classist imaginings of obesity as a working-class embodiment. The paper will further question the understanding of the rural as a food desert, showing the ways in which rural teens acquire fresh, healthy foods in part through an informal economy of food growing and sharing. PMID:23694820

McPhail, Deborah; Chapman, Gwen E; Beagan, Brenda L

2013-07-01

366

Delineation of Shallow Subsurface Structure by Azimuthal Resistivity Sounding and Joint Inversion of VES-TEM Data: Case Study near Lake Qaroun, El Fayoum, Egypt  

NASA Astrophysics Data System (ADS)

An azimuthal resistivity survey was conducted at the transition zone between the desert area and the cultivated land near Lake Qaroun, Egypt. This area has been affected by an east-west trending fault system as indicated from the surface geology. Apparent resistivity values were plotted along azimuth on a polar diagram. Resistivity anomalies, for most of the AB/2 values with long axes strike in a direction parallel to the contact between the desert and cultivated lands, indicate the presence of electrical macro-anisotropy, mainly due to the faulting effect, at this area. Vertical electrical soundings (VES) and transient electromagnetic (TEM) measurements were conducted at eight stations along a line that crosses the boundary between the desert and cultivated land. Joint inversion of VES-TEM data was successfully used for identification of the subsurface lithostratigraphic succession and demonstrated the effect of the fault zone on the investigated subsurface medium. Apparent anisotropy coefficients at all current electrode spacings were calculated, plotted against AB/2 values and compared with the geoelectrical cross section. The effect of the fault zone was detected at AB/2 spacings equal to 100 m and extended downward and is largely related to the depth of the fault, as indicated in the constructed cross section.

Massoud, Usama; Qady, Gad El; Metwaly, Mohamed; Santos, Fernando

2009-04-01

367

Western Samoa.  

PubMed

This discussion of Western Samoa, which lies 2575 km northeast of Auckland, New Zealand, focuses on the following: geography; the people; history; government; political conditions; the economy; foreign relations; and relations the US. The population of Western Samoa, as of 1985, totals 163,000 with an annual growth rate of 0.9%. The infant mortality rate is 13/1000; life expectancy is 65 years. The main islands are formed ranges of extinct volcanoes. Volcanic activity last occurred in 1911. More than 2000 years age, waves of Polynesians migrated from Southeast Asia to the Samoan Islands. Samoans are the 2nd largest Polynesian group, after the Maoris of New Zealand, and speak a Polynesian dialect. Samoans have tended to retain their traditional ways despite exposure to European influence for more than 150 years. Most Samoans live within the traditional social system based on an extended family group, headed by a chief. Western Samoans are Christian. Education is free but not compulsory. In 1967, 95% of the children of primary school age attended school. From 1947 to 1961, a series of constitutional advances, assisted by visits from UN missions, brought Western Samoa from dependent status to self-government and finally to independence. The 1960 constitution is based on the British pattern of parliamentary democracy, modified to take Samoan customs into account. The present head of state holds his position for life. Future heads of state will be elected by the Legislative Assembly for 5-year terms. The Parliament consists of the Legislative Assembly and the head of state. The Supreme Court is the superior court of record and has full jurisdiction in civil, criminal, and constitutional matters. The "matai" of chief system still dominates the politics of Western Samoa, although several political parties have been formed and seem to be taking root. The "matai" system is a predominantly conservative force but does provide for change. Western Samoa is predominantly agricultural, and the village communities maintain an economy based on farming and fishing. Stagnating or declining agricultural production has resulted in an increasing dependence on imports. The islands have few resources and no deposits of commercially valuable minerals. Western Samoa suffers from a persistent current accounts deficit. The government's primary goal is to improve agricultural production. Western Samoa has particularly close relations with its Pacific island neighbors and New Zealand. The US has taken a special interest in Western Samoa's economic development. PMID:12178131

1985-12-01

368

Estimating the completeness of under-5 death registration in Egypt  

Microsoft Academic Search

To evaluate the completeness of registration of infant and child deaths in Egypt, reinterviews were conducted with families\\u000a who had reported a death of a child under age 5 in the five years before the survey for two national surveys recently conducted\\u000a in Egypt: the United Nations PAPCHILD survey of1990-1991 and the Egyptian Demographic and Health Survey (EDHS) of 1992.

Stan Becker; Youssef Waheeb; Bothaina EL-Deeb; Nagwa Khallaf; Robert Black

1996-01-01

369

Childhood unintentional injuries surveillance in Ismailia governorate, Egypt  

Microsoft Academic Search

ObjectiveTo determine the epidemiology and risk factors of childhood injuries in Ismailia governorate Egypt.MethodsThis is the Egyptian chapter of the Global Childhood Unintentional Injury Surveillance study, which employed quota sampling of children 0–11 years old presenting to the Emergency Department. This surveillance was conducted in the University Hospital of Suez Canal University Egypt, for selected months in 2007. Children with

H El-Sayed; A Hyder; O Zekry; D Sugerman; S Abdel-Hamid; H Abbas; P Puvanachandra

2010-01-01

370

Nile River, Lake Nasser, Aswan High Dam, Egypt, Africa  

NASA Technical Reports Server (NTRS)

Lake Nasser, (24.0N, 33.0E) at the Aswan High Dam on the Nile River, in Egypt is the world's second largest artificial lake, extending 500 km, in length and about 5000 sq. km. in area. The lake has a storage capacity sufficient to irrigate farms in Egypt and Sudan year round allowing up to three harvests per year. Other benefits include year round river navagation, hydroelectric power, more fish harvests, reduced flooding and more industrial employment. opportunites.

1992-01-01

371

Mycotoxigenic fungi in peanuts from different geographic regions of Egypt  

Microsoft Academic Search

To understand the importance of mycotoxigenic fungi in Egyptian peanuts, samples from five regions (Alexandria, El-Beheira,\\u000a El-Sharqiya, El-Daqahelaya in northern Egypt and Asyut, southern Egypt) in two seasons (2007, 2008) were collected. Aspergillus was consistently the most frequent genus in seeds and in-shell peanuts and was the dominant mycotoxigenic component of the\\u000a mycobiota. There was no direct correlation between the

Yousef Sultan; Naresh Magan

2010-01-01

372

Female circumcision is curbed in Egypt.  

PubMed

In the wake of the death of an 11-year-old girl the Egyptian government has banned any government-affiliated medical staff from performing female circumcision. Egyptian health policy has shifted from trying to control the practice by keeping it under government supervision towards condemnation. In October 1995 the health minister banned female circumcision from being carried out in state hospitals, a direct reversal of a 1994 decree that asked state hospitals to set aside one day a week for performing the procedure. The further restriction follows an incident in July 1996 when an 11-year-old girl bled to death in the rural area of Mansoora after being circumcised by a barber. Female genital mutilation in Egypt changed from an accepted custom to a political hot topic after the news network CNN in September 1994 featured the circumcision of a 9-year-old girl from Cairo. The footage embarrassed Egyptians and fueled an outcry by women's groups and nongovernmental organizations. Statistics compiled in 1994 by Egypt's former ministry of population estimated that between 70% and 90% of Egyptian women were circumcised. But a more recent survey puts the figure even higher, with 97% of women in both rural and urban areas having been circumcised. Circumcisions range from clitoridectomies to almost total removal of the outside genitalia. The practice seems to be rooted in both African tradition and Islamic beliefs, although many Islamic countries do not practice female circumcision. The main motivation seems to be in controlling women's sexual urges, and the belief that circumcision makes a woman more feminine. A university professor of gynecology teaches his medical students that circumcision is healthier for the woman. Most circumcisions in Egypt are performed by barbers or midwives, despite a sporadically enforced law forbidding the operation by anyone but a trained medical staff member. There is a high rate of complications, with some operations leading to infertility. Groups like the Population Council hope that further education and public debate will help to stop the practice. PMID:8704530

Wiens, J

1996-08-01

373

Opportunities for woody crop production using treated wastewater in Egypt. II. Irrigation strategies.  

PubMed

An Egyptian national program targets annual reuse of 2.4 billion m3 of treated wastewater (TWW) to irrigate 84,000 ha of manmade forests in areas close to treatment plants and in the desert. To evaluate the feasibility of such afforestation efforts, we describe information about TWW irrigation strategies based on (1) water use of different tree species, (2) weather conditions in different climate zones of Egypt, (3) soil types and available irrigation systems, and (4) the requirement to avoid deep percolation losses that could lead to groundwater contamination. We conclude that drip irrigation systems are preferred, that they should in most cases use multiple emitters per tree in order to increase wetted area and decrease depth of water penetration, that deep rooting should be encouraged, and that in most situations irrigation system automation is desirable to achieve several small irrigations per day in order to avoid deep percolation losses. We describe directed research necessary to fill knowledge gaps about depth of rooting of different species in sandy Egyptian soils and environments, tree crop coefficients needed for rational irrigation scheduling, and depth of water penetration under different irrigation system designs. A companion paper addresses recommendations for afforestation strategies (see Zalesny et al. 2011, this issue). PMID:22046755

Evett, Steven R; Zalesny, Ronald S; Kandil, Nabil F; Stanturf, John A; Soriano, Chris

2011-01-01

374

A genetic assessment of the recovery units for the mojave population of the desert tortoise, Gopherus agassizii  

USGS Publications Warehouse

In the 1994 Recovery Plan for the Mojave population of the desert tortoise, Gopherus agassizii, the US Fish and Wildlife Service established 6 recovery units by using the best available data on habitat use, behavior, morphology, and genetics. To further assess the validity of the recovery units, we analyzed genetic data by using mitochondrial deoxyribonucleic acid (mtDNA) sequences and nuclear DNA microsatellites. In total, 125 desert tortoises were sampled for mtDNA and 628 for microsatellites from 31 study sites, representing all recovery units and desert regions throughout the Mojave Desert in California and Utah, and the Colorado Desert of California. The mtDNA revealed a great divergence between the Mojave populations west of the Colorado River and those occurring east of the river in the Sonoran Desert of Arizona. Some divergence also occurred between northern and southern populations within the Mojave population. The microsatellites indicated a low frequency of private alleles and a significant correlation between genetic and geographic distance among 31 sample sites, which was consistent with an isolation-by-distance population structure. Regional genetic differentiation was complementary to the recovery units in the Recovery Plan. Most allelic frequencies in the recovery units differed. An assignment test correctly placed most individuals to their recovery unit of origin. Of the 6 recovery units, the Northeastern and the Upper Virgin River units showed the greatest differentiation; these units may have been relatively more isolated than other areas and should be managed accordingly. The Western Mojave Recovery Unit, by using the new genetic data, was redefined along regional boundaries into the Western Mojave, Central Mojave, and Southern Mojave recovery units. Large-scale translocations of tortoises and habitat disturbance throughout the 20th century may have contributed to the observed patterns of regional similarity. ?? 2007 Chelonian Research Foundation.

Murphy, R. W.; Berry, K. H.; Edwards, T.; McLuckie, A. M.

2007-01-01

375

Egypt: Secrets of an Ancient World  

NSDL National Science Digital Library

While ancient Egyptian civilization has captured the public interest and imagination in recent decades, this well-designed site from the National Geographic Society places its focus on the pyramids created several millennia ago. In the site's most compelling feature, titled Explore the Pyramids, visitors can scroll across the different pyramids, revealing their interior organization and a number of facts about their construction and so on. A brief timeline also gives some information about each of the different Egyptian dynasties. Educators will find much to enjoy here, as the site provides different lesson plans for students, complete with critical questions for discussion and lesson objectives. Finally, there is an online journal written by National Geographic reporter Nancy Gupton that documents her own personal experiences traveling around the pyramids of Egypt.

2002-01-01

376

Environmental impact of pesticides in Egypt.  

PubMed

The first use of petroleum-derived pesticides in Egyptian agriculture was initiated in 1950. Early applications consisted of distributing insecticidal dusts containing DDT/BHC/S onto cotton fields. This practice was followed by use of toxaphene until 1961. Carbamates, organophosphates, and synthetic pyrethroids were subsequently used, mainly for applications to cotton. In addition to the use of about 1 million metric tons (t) of pesticides in the agricultural sector over a 50-yr period, specific health and environmental problems are documented in this review. Major problems represented and discussed in this review are human poisoning, incidental toxicity to farm animals, insect pest resistance, destruction of beneficial parasites and predators, contamination of food by pesticide residues, and pollution of environmental ecosystems. Several reports reveal that chlorinated hydrocarbon pesticide residues are still detectable in several environmental compartments; however, these residues are in decline. Since 1990, there is a growing movement toward reduced consumption of traditional pesticides and a tendency to expand use of biopesticides, including "Bt," and plant incorporated protectants (PIPs). On the other hand, DDT and lindane were used for indoor and hygienic purposes as early as 1952. Presently, indoor use of pesticides for pest control is widespread in Egypt. Accurate information concerning the types and amounts of Egyptian household pesticide use, or numbers of poisoning or contamination incidents, is unavailable. Generally, use of indoor pesticides is inadequately managed. The results of a survey of Egyptian farmers' attitudes toward pesticides and their behavior in using them garnered new insights as to how pesticides should be better controlled and regulated in Egypt. PMID:19025091

Mansour, Sameeh A

2008-01-01

377

Scaling properties of rainfall and desert dust in the Canary Islands  

NASA Astrophysics Data System (ADS)

Precipitation and desert dust event occurrence time series measured in the Canary Islands region are examined with the primary intention of exploring their scaling characteristics as well as their spatial variability in terms of the island's topography and geographical orientation. In particular, the desert dust intrusion regime in the islands is studied in terms of its relationship with visibility. Analysis of dust and rainfall events over the archipelago exhibits distributions in time that obey power laws. Results show that the rain process presents a high clustering and irregular pattern on short timescales and a more scattered structure for long ones. In contrast, dustiness presents a more uniform and dense structure and, consequently, a more persistent behaviour on short timescales. It was observed that the fractal dimension of rainfall events shows an important spatial variability, which increases with altitude, as well as towards northern latitudes and western longitudes.

Peñate, I.; Martín-González, J. M.; Rodríguez, G.; Cianca, A.

2013-12-01

378

Observation of local cloud and moisture feedbacks over high ocean and desert surface temperatures  

NASA Technical Reports Server (NTRS)

New data on clouds and moisture, made possible by reanalysis of weather satellite observations, show that the atmosphere reacts to warm clusters of very high sea surface temperatures in the western Pacific Ocean with increased moisture, cloudiness, and convection, suggesting a negative feedback limiting the sea surface temperature rise. The reverse was observed over dry and hot deserts where both moisture and cloudiness decrease, suggesting a positive feedback perpetuating existing desert conditions. In addition, the observations show a common critical surface temperature for both oceans and land; the distribution of atmospheric moisture is observed to reach a maximum value when the daily surface temperatures approach 304 +/- 1 K. These observations reveal complex dynamic-radiative interactions where multiple processes act simultaneously at the surface as well as in the atmosphere to regulate the feedback processes.

Chahine, Moustafa T.

1995-01-01

379

Inventory of Research on Weather and Climate of Desert Environments.  

National Technical Information Service (NTIS)

Contents: Discussion of state of knowledge; (Climatic data, climatic data for each desert, synoptic climatology, weather systems, desert storms, upper-air circulations, aridity, climatic typing and indexes of aridity, weather modification, microclimate, r...

C. H. Reitan C. R. Green

1967-01-01

380

Characteristics and Influential Factors of Food Deserts. Report Summary.  

National Technical Information Service (NTIS)

USDAs Economic Research Service previously identified approximately 6,500 food desert tracts in the United States based on 2000 Census and 2006 data on locations of supermarkets, supercenters, and large grocery stores. These food deserts are areas where p...

M. Ver Ploeg P. Dutko T. Farrigan

2012-01-01

381

The heat is on: desert tortoises and survival  

USGS Publications Warehouse

To highlight USGS scientists' research and build support for the work being done to help with desert tortoise recovery. To educate people about desert tortoises, their habitat needs, and what people might do to help. Length: 30 minutes

Wessells, Stephen M.; Schwarzbach, Steven E.

2010-01-01

382

Desert Bighorn Sheep: A Guide to Selected Management Practices,  

National Technical Information Service (NTIS)

The guide summarizes pertinent literature on four topics of desert bighorn sheep ecology and management: (1) their water requirements and adaptations are compared with those of other desert-dwelling ungulates; (2) the effects of human activities such as m...

N. S. Smith P. R. Krausman

1988-01-01

383

Biogenic volatile organic compound emissions from desert vegetation of the southwestern US  

NASA Astrophysics Data System (ADS)

Thirteen common plant species in the Mojave and Sonoran Desert regions of the western US were tested for emissions of biogenic non-methane volatile organic compounds (BVOCs). Only two of the species examined emitted isoprene at rates of 10 ?g C g -1 h -1or greater. These species accounted for <10% of the estimated vegetative biomass in these arid regions of low biomass density, indicating that these ecosystems are not likely a strong source of isoprene. However, isoprene emissions from these species continued to increase at much higher leaf temperatures than is observed from species in other ecosystems. Five species, including members of the Ambrosia genus, emitted monoterpenes at rates exceeding 2 ?g C g -1 h -1. Emissions of oxygenated compounds, such as methanol, ethanol, acetone/propanal, and hexanol, from cut branches of several species exceeded 10 ?g C g -1 h -1, warranting further investigation in these ecosystems. Model extrapolation of isoprene emission measurements verifies recently published observations that desert vegetation is a small source of isoprene relative to forests. Annual and daily total model isoprene emission estimates from an eastern US mixed forest landscape were 10-30 times greater than isoprene emissions estimated from the Mojave site. Monoterpene (and possibly oxygenated terpene and sesquiterpene) emissions may be more comparable, as annual forest terpene emission model estimates were 3-8 times greater than those from the Mojave Desert, and were within a factor of 2 for peak summertime fluxes. Primary productivity and leaf biomass of desert ecosystems are very dependent on annual precipitation, and our model results indicate that there can be at least a three-fold difference in total annual BVOC emissions between dry and wet years. We recommend additional studies of desert plant BVOC emissions, especially those that focus on sesquiterpenes, oxygenated compounds, and the effects of soil moisture, temperature, humidity, and seasonality. Landscape flux studies are needed to test BVOC model estimates and to verify BVOC influences on regional atmospheric chemistry.

Geron, Chris; Guenther, Alex; Greenberg, Jim; Karl, Thomas; Rasmussen, Rei

384

Introduction and domestication of woody plants for sustainable agriculture in desert areas  

NASA Astrophysics Data System (ADS)

High radiation in hot deserts results in high salinity, especially in irrigated fields. Whenever not treated properly, this salinization may harm crops and eventually bring to soil destruction, field abandonment, or literally desertification. Furthermore, the range of crops that can be grown commercially in hot deserts is limited (Nerd et al. 1990). With the globalization of the last century, Introduction of exotic species for commercial use became more accessible. However, these attempts may involve extreme land changes including establishment of potential invasive species. Therefore domestication of native species should be preferred rather than introduction of exotics. In the last six years we did first steps of domesticating several native species, searching for commercial potential (pharmaceutics, food, biomass for energy and desalination of constructed wetlands). We studied aspects of desert plant physiology in drought and saline conditions. We wish to share the knowledge we gained regarding the physiology and commercial potential of the following desert plant species: 1) Bassia indica is an annual halophyte. We proposed to use it for salt phytoremediation in constructed wetlands for wastewater treatment and as feed for livestock; 2) Commiphora gileadensis is considered as the balm tree of Judea, praised for its use as holy oil and in perfumes but also considered as a cure for many diseases. C. gileadensis today grows naturally in southwest Arabia and Somaliland. We found anti-proliferative and apoptotic effect of C. gileadensis extracts on several human cancer cells. Ben Gurion University of the Negev has patented these findings. 3) Artemisia sieberi and A. judaica are both known for various therapeutic traits. While studying effects of irrigation intensity on these traits, some allopathic characters were discovered. 4) Fichus palmate disappeared from Israel, but remind in neighbouring Jordan and Egypt. This tree may serve as a robust stand for fig plantation in arid conditions. 5) Balanites aegyptiaca is potentially a good biomass crop and good feed for grazers as goats. We illuminated differences related to drought tolerance between two distinct ecotypes. Attempts to develope sustainable agriculture based on local species will save resources (water, fertilizers, insecticides and herbicides), keep endangered plant species and enhance vegetation reestablishment.

Shelef, Oren; Soloway, Elaine; Rachmilevitch, Shimon

2014-05-01

385

Applied Science and Technology Research in Egypt: Development of Egyptian Scientific and Technical Information Services.  

National Technical Information Service (NTIS)

A project undertaken to improve scientific and technical information (STI) services in Egypt is summarized. Project organization and management in Egypt and the United States are discussed and four technical reports addressing the project design and imple...

1982-01-01

386

78 FR 23208 - Importation of Fresh Oranges and Tangerines From Egypt Into the United States  

Federal Register 2010, 2011, 2012, 2013

...capitata); however, imports of oranges from Egypt were suspended in July 2002 due to the establishment of peach fruit fly (Bactrocera zonata), which is also a pest of citrus in Egypt. Currently, the importation of fresh oranges and...

2013-04-18

387

76 FR 73759 - Culturally Significant Objects Imported for Exhibition Determinations: “Ancient Egypt-Art and...  

Federal Register 2010, 2011, 2012, 2013

...Ancient Egypt--Art and Magic: Treasures From the Foundation Gandur pour L'Art, Geneva, Switzerland'' SUMMARY: Notice...exhibition ``Ancient Egypt--Art and Magic: Treasures from the Foundation Gandur pour L'Art, Geneva, Switzerland'' imported...

2011-11-29

388

Egypt: The Egyptian American Rural Improvement Service, a Point Four Project, 1952-63.  

National Technical Information Service (NTIS)

The long-term impact of the model Egyptian American Rural Improvement Service (EARIS) project (1952-63), still Egypt's most successful land reclamation effort, is evaluated in this report. Alignment with Egypt's top political and developmental goals enabl...

P. R. Johnson A. E. Dahry R. Dekmejian E. McJunkin R. Morrow

1983-01-01

389

Assessment and management of water resources in Egypt to face drought and water scarcity  

NASA Astrophysics Data System (ADS)

Egypt is one of the countries hardest hit by global and climate change. Challenges include population growth; increased demands for food, water, and energy; as well as changing land use patterns and urbanization. Egypt's part of the Mediterranean is characterized by a very complex hydrological system, as it lacks rainfall (Cairo average 30 mm/year) and it is completely dependent on the Nile river flow. The growth of the Egyptian population and its economy in the near future leads to an increase in the demand for water and the overall water allocation priority basically is: first drinking water, then industry, and whatever is remaining will be available for agriculture and nature. Because the agricultural sector uses more than 80 per cent of available water, the main option available to reduce water scarcity in the priority sectors of the economy is to allocate less to the agriculture sector. Scientifically based advances in facing future drought and water scarcity through innovations increasing yields and food security by measures leading to "more crop per drop" are required. New and modern large- and medium-scale agriculture is being developed in desert areas with participation of the private sector for investments. To prepare the farming community and others elsewhere, for the future situation of water shortages, a paradigm shift is needed. New farming systems under tight water supply conditions are in development to prepare for a future with less water. Egyptian farming systems need a major transition to prevent further marginalization of agriculture, which would also have a major impact on food security. Central to this transition should be the increase of value generated per volume available water, also referred to as "more crop per drop" or "more cash per splash". There is room for the urgently required improvement: the present return on water in agriculture in Egypt is about US 0.25 /m3, where values of over US 1 /m3 are "easily" reached elsewhere. Moreover, innovations on resource efficiency enabling use of rest and by-products of one agricultural activity as an input for another one will be profitable for the food producers and will also be better for the environment. The creative design process to reach the required technological and policy innovations contributes to the developed adaptation strategy to face drought and water scarcity. Results will incorporate some previously un-thought of options. The issues of water scarcity and drought have consequences and implications that can no longer be adequately addressed by any one of the Ministries alone. Many other government departments and agencies must be involved and decisions will have to be made at the highest political level. All policies in Egypt must be conscious of the limitations in water availability, and water policies need to address technological developments as well as the full range of other issues, including: macro-economic factors, economic issues that influence farm-level decisions, development of human capital, governance, and financial risk management.

Wolters, Wouter; El Guindy, Samia; Salah El Deen, Magdy; Roest, Koen; Smit, Robert; Froebrich, Jochen

2013-04-01

390

Desert basins of the Southwest  

USGS Publications Warehouse

Ground water is among the Nation’s most important natural resources. It provides drinking water to urban and rural communities, supports irrigation and industry, sustains the flow of streams and rivers, and maintains riparian and wetland ecosystems. In many areas of the Nation, the future sustainability of ground-water resources is at risk from overuse and contamination. Because ground-water systems typically respond slowly to human actions, a long-term perspective is needed to manage this valuable resource. This publication is one in a series of fact sheets that describe ground-water-resource issues across the United States, as well as some of the activities of the U.S. Geological Survey that provide information to help others develop, manage, and protect ground-water resources in a sustainable manner. Ground-water resources in the Southwest are among the most overused in the United States. Natural recharge to aquifers is low and pumping in many areas has resulted in lowering of water tables. The consequences of large-scale removal of water from storage are becoming increasingly evident. These consequences include land subsidence; loss of springs, streams, wetlands and associated habitat; and degradation of water quality. Water managers are now seeking better ways of managing ground-water resources while looking for supplemental sources of water. This fact sheet reviews basic information on ground water in the desert basins of the Southwest. Also described are some activities of the U.S. Geological Survey (USGS) that are providing scientific information for sustainable management of ground-water resources in the Southwest. Ground-water sustainability is defined as developing and using ground water in a way that can be maintained for an indefinite time without causing unacceptable environmental, economic, or social consequences.

Leake, Stanley A.; Konieczki, Alice D.; Rees, Julie A. H.

2000-01-01

391

Micromorphology of takyrs and the desert ``papyrus'' of Southwestern Turkmenia  

NASA Astrophysics Data System (ADS)

The perception of takyrs as clayey mineral soils extremely poor in humus and occurring in deserts was supported by micromorphological studies with the first ones being performed by I.I. Feofarova for the takyrs in Western Turkmenia. However, in the fundamental monograph of 1956, there were abundant data on the contribution of biota (primarily of algae and invertebrates) to the takyr formation. The importance of the biota was emphasized by N.I. Bazilevich, who was an active participant in terrain and analytical investigations of Western Turkmenia takyrs. The micromorphological analysis, along with the studies of the chemical and mineralogical properties of the algal takyr on the Kopet-Dag piedmont plain, made it possible to introduce some corrections to the concepts concerning the mechanisms of takyr development; the contribution of bluegreen algae, microorganisms, and zooplankton was shown to be prominent. The available information on the properties and ecology of blue-green algae enabled the authors to interpret both their own data and the micromorphological descriptions made by I.I. Feofarova in the 1950s. The uppermost subhorizons are proposed to be regarded as the soil miniprofiles, whose properties are strongly affected by the activity of aquatic and terrestrial microorganisms, rather than the sedimentation strata.

Lebedeva-Verba, M. P.; Gerasimova, M. I.

2010-11-01

392

Ephemeral lakes and desert dust sources  

NASA Astrophysics Data System (ADS)

The processes that determine which areas are strong sources of mineral aerosols are not well known. In this study we consider the role of ephemeral lakes in modulating emissions of atmospheric mineral aerosols. We focus on two ephemeral lake regions that have been identified as source regions: the zone of Chotts in Tunisia and Algeria, and Etosha Pan in Namibia. Comparisons of satellite retrieved inundation data and the TOMS absorbing aerosol index suggest that during some periods of inundation, desert dust loadings are reduced. There is some indication that after flooded areas have dried there is increased dust loading. However, the role of the inundated ephemeral lake compared with nearby regions in modulating desert dust sources is unclear, in addition, problems with interpreting the TOMS AI make conclusions difficult. More research is required to understand the small-scale sources of atmospheric desert dust in dry, unvegetated, topographic lows.

Mahowald, Natalie M.; Bryant, Robert G.; del Corral, John; Steinberger, Linda

2003-01-01

393

Lessons in Combat Service Support Tactical Mobility: The Afghanistan Conflict, Falklands War and Operation Desert Shield/Desert Storm.  

National Technical Information Service (NTIS)

This monograph examines lessons in combat service support (CSS) tactical mobility during the Afghanistan Conflict, the Falklands War, and Operation Desert Shield/Desert Storm. The unique environments of these operations have significant differences in ter...

C. D. Clair

1993-01-01

394

Concentration, size-distribution and deposition of mineral aerosol over Chinese desert regions  

NASA Astrophysics Data System (ADS)

The mass-particle size distributions (MSDs) of 9 elements in ground-based aerosol samples from dust storm (DS) and non-dust storm (N-DS) periods were determined for 12 sites in 9 major desert regions in northern China. The masses of the 9 elements (Al, Fe, K, Mg, Mn, Sc, Si, Sr and Ti) in the atmosphere were dominated by local mineral dust that averaged 270?g m-3, and the MSDs for the elements were approximately log-normal. On the basis of Al data, the<10?m particles account for ~84% of the total dust mass over the deserts. Model-calculated ("100-step" method) dry deposition velocities (Vd) for the 9 dust-derived elements during N-DS periods ranged from 4.4 to 6.8cms-1, with a median value of 5.6cms-1. On the basis of a statistical relationship between D99% (the dust particle diameter corresponding to the uppermost 1% of the cumulative mass distribution) and Vd, one can also predict dry velocities, especially when D99% ranges from 30 to 70?m. This provides a simple way to reconstruct Vd for dust deposits (like aeolian loess sediments in the Loess Plateau). The estimated daily dry deposition fluxes were higher during DS vs. N-DS periods, but in most cases, the monthly averaged fluxes were mainly attributable to N-DS dust. Two regions with high dust loading and fluxes are identified: the "Western High-Dust Desert" and the "Northern High-Dust Desert", with Taklimakan Desert and Badain Juran Desert as their respective centers. These are energetic regions in which desert-air is actively exchanged, and these apparently are the major source areas for Asian dust.

Zhang, Xiao Y.; Arimoto, R.; Zhu, G. H.; Chen, T.; Zhang, G. Y.

1998-09-01

395

Oxalosis in wild desert tortoises, Gopherus agassizii.  

PubMed

We necropsied a moribund, wild adult male desert tortoise (Gopherus agassizii) with clinical signs of respiratory disease and elevated plasma biochemical analytes indicative of renal disease (blood urea nitrogen [415 mg/dl], uric acid [11.8 mg/dl], sodium [>180 mmol/l] and chloride [139 mmol/l]). Moderate numbers of birefringent oxalate crystals, based on infrared and electron microscopy, were present within renal tubules; small numbers were seen in colloid within thyroid follicles. A retrospective analysis of 66 additional cases of wild desert tortoises was conducted to determine whether similar crystals were present in thyroid and kidney. The tortoises, from the Mojave and Sonoran deserts, were necropsied between 1992 and 2003 and included juveniles and adults. Tortoises were classified as healthy (those that died due to trauma and where no disease was identified after necropsy and evaluation by standard laboratory tests used for other tortoises) or not healthy (having one or more diseases or lesions). For all 67 necropsied tortoises, small numbers of crystals of similar appearance were present in thyroid glands from 44 of 54 cases (81%) and in kidneys from three of 65 cases (5%). Presence of oxalates did not differ significantly between healthy and unhealthy tortoises, between age classes, or between desert region, and their presence was considered an incidental finding. Small numbers of oxalate crystals seen within the kidney of two additional tortoises also were considered an incidental finding. Although the source of the calcium oxalate could not be determined, desert tortoises are herbivores, and a plant origin seems most likely. Studies are needed to evaluate the oxalate content of plants consumed by desert tortoises, and particularly those in the area where the tortoise in renal failure was found. PMID:19901374

Jacobson, Elliott R; Berry, Kristin H; Stacy, Brian; Huzella, Louis M; Kalasinsky, Victor F; Fleetwood, Michelle L; Mense, Mark G

2009-10-01

396

A Reservoir of Nitrate Beneath Desert Soils  

USGS Publications Warehouse

A large reservoir of bioavailable nitrogen (upto ???104 kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of and regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for warm deserts and arid shrublands worldwide and by 3 to 16% globally. Subsoil nitrate accumulation indicates long-term leaching from desert soils, impelling further evaluation of nutrient dynamics in xeric ecosystems. Evidence that subsoil accumulations are readily mobilized raises concern about groundwater contamination after land-use or climate change.

Walvoord, M. A.; Phillips, F. M.; Stonestrom, D. A.; Evans, R. D.; Hartsough, P. C.; Newman, B. D.; Striegl, R. G.

2003-01-01

397

When science became Western: historiographical reflections.  

PubMed

While thinking about the notion of the "global" in the history of the history of science, this essay examines a related but equally basic concept: the idea of "Western science." Tracing its rise in the nineteenth century, it shows how it developed as much outside the Western world as within it. Ironically, while the idea itself was crucial for the disciplinary formation of the history of science, the global history behind this story has not been much attended to. Drawing on examples from nineteenth-century Egypt and China, the essay begins by looking at how international vectors of knowledge production (viz., missionaries and technocrats) created new global histories of science through the construction of novel genealogies and through a process of conceptual syncretism. Turning next to the work of early professional historians of science, it shows how Arabic and Chinese knowledge traditions were similarly reinterpreted in light of the modern sciences, now viewed as part of a diachronic and universalist teleology ending in "Western science." It concludes by arguing that examining the global emergence of the idea of Western science in this way highlights key questions pertaining to the relation of the history of science to knowledge traditions across the world and the continuing search for global histories of science. PMID:20575492

Elshakry, Marwa

2010-03-01

398

Density currents as a desert dust mobilization mechanism  

NASA Astrophysics Data System (ADS)

The formation and propagation of density currents are well studied processes in fluid dynamics with many applications to other science fields. In the atmosphere, density currents are usually meso-?/? mechanisms and are often associated with storm downdrafts. These storms are responsible for the formation of severe dust episodes (haboobs) over desert areas. In the present study, the formation of a convective cool pool and the associated dust mobilization is examined for a representative event over the western part of Sahara desert. The physical processes involved in the mobilization of dust are described in the framework of the integrated atmospheric-air quality RAMS/ICLAMS model. Dust is effectively produced due to the development of near surface vortices and increased turbulence mixing along the frontal line. Increased dust emissions and recirculation of the elevated particles inside the density current head result in the formation of a moving "dust wall". Transport of the uplifted dust in higher layers - outside of the density current - occurs mainly in three ways: (1) uplifting of preexisting dust over the frontal line with the aid of the strong updraft (2) entrainment at the upper part of the density current head due to turbulent mixing (3) vertical mixing after the dilution of the system. The role of the produced dust in the associated convective cloud system was found to be limited. Proper representation of convective processes and dust fluxes requires the use of high resolution (cloud resolving) model configuration and online parameterization of dust production. Haboob-type of dust storms are effective dust sources and should be treated accordingly in dust modeling applications.

Solomos, S.; Kallos, G.; Mavromatidis, E.; Kushta, J.

2012-08-01

399

Density currents as a desert dust mobilization mechanism  

NASA Astrophysics Data System (ADS)

The formation and propagation of density currents are well studied processes in fluid dynamics with many applications in other science fields. In the atmosphere, density currents are usually meso-?/? phenomena and are often associated with storm downdrafts. These storms are responsible for the formation of severe dust episodes (haboobs) over desert areas. In the present study, the formation of a convective cool pool and the associated dust mobilization are examined for a representative event over the western part of Sahara desert. The physical processes involved in the mobilization of dust are described with the use of the integrated atmospheric-air quality RAMS/ICLAMS model. Dust is effectively produced due to the development of near surface vortices and increased turbulent mixing along the frontal line. Increased dust emissions and recirculation of the elevated particles inside the head of the density current result in the formation of a moving "dust wall". Transport of the dust particles in higher layers - outside of the density current - occurs mainly in three ways: (1) Uplifting of preexisting dust over the frontal line with the aid of the strong updraft (2) Entrainment at the upper part of the density current head due to turbulent mixing (3) Vertical mixing after the dilution of the system. The role of the dust in the associated convective cloud system was found to be limited. Proper representation of convective processes and dust mobilization requires the use of high resolution (cloud resolving) model configuration and online parameterization of dust production. Haboob-type dust storms are effective dust sources and should be treated accordingly in dust modeling applications.

Solomos, S.; Kallos, G.; Mavromatidis, E.; Kushta, J.

2012-11-01

400

Amplified Fragment Length Polymorphism Diversity in Cephalosporium maydis from Egypt.  

PubMed

ABSTRACT Cephalosporium maydis, the causal agent of late wilt of maize, was first described in Egypt in the 1960s, where it can cause yield losses of up to 40% in susceptible plantings. We characterized 866 isolates of C. maydis collected from 14 governates in Egypt, 7 in the Nile River Delta and 7 in southern (Middle and Upper) Egypt, with amplified fragment length polymorphism (AFLP) markers. The four AFLP primer-pair combinations generated 68 bands, 25 of which were polymorphic, resulting in 52 clonal haplotypes that clustered the 866 isolates into four phylogenetic lineages. Three lineages were found in both the Nile River Delta and southern Egypt. Lineage IV, the most diverse group (20 haplotypes), was recovered only from governates in the Nile River Delta. In some locations, one lineage dominated (up to 98% of the isolates recovered) and, from some fields, only a single haplotype was recovered. Under field conditions in Egypt, there is no evidence that C. maydis reproduces sexually. The nonuniform geographic distribution of the pathogen lineages within the country could be due to differences in climate or in the farming system, because host material differs in susceptibility and C. maydis lineages differ in pathogenicity. PMID:18943166

Saleh, Amgad A; Zeller, Kurt A; Ismael, Abou-Serie M; Fahmy, Zeinab M; El-Assiuty, Elhamy M; Leslie, John F

2003-07-01

401

Trophic relationships of small nonnative fishes in a natural creek and several agricultural drains flowing into the salton sea, and their potential, effects on the endangered desert pupfish  

USGS Publications Warehouse

This study was conducted to characterize trophic relationships of small nonnative fishes and to determine if predation by these fishes contributes to the decline of desert pupfish (Cyprinodon macularius), an endangered cyprinodont on the verge of extinction. We sampled 403 hybrid Mozambique tilapias (Oreochromis mossambica by O. urolepis), 107 redbelly tilapias (Tilapia zillii), 32 longjaw mudsuckers (Gillkhthys mirabilis), 182 western mosquitofish (Gambusia affinis), 222 sailfin mollies (Poecilia latipinna), 63 shortfin mollies (Poecilia mexicana), and 235 porthole livebearers (Poecilurpsis gracilis) from a natural creek and four agricultural drains during September 1999- December 2001. Evidence of piscivory was in gastrointestinal contents of 14 hybrid Mozambique tilapias, 3 redbelly tilapias, 10 longjaw mudsuckers, 8 western mosquitofish, 2 sailfin mollies, and 8 porthole livebearers. Although digestion often was too advanced for identification of fishes consumed by nonnative fishes, remains of desert pupfish were in gastrointestinal contents of a longjaw mudsucker. Our findings, along with Field evidence from other studies that inverse relationships exist between abundances of desert pupfish and nonnative species, are consistent with the hypothesis that predation by nonnative species is contributing to decline of desert pupfish. We suspect that competitive interactions with nonnative fishes might also adversely affect abundance of desert pupfish.

Martin, B. A.; Saiki, M. K.

2009-01-01

402

Alluvial sediment or playas: What is the dominant source of sand and silt in desert soil vesicular A horizons, southwest USA  

NASA Astrophysics Data System (ADS)

Vesicular A (Av) soil horizons form beneath desert pavements from the accretion of aeolian sediment (dust) commonly thought to be derived primarily from desiccating pluvial lakes and playas, with contributions from ephemeral washes and alluvial fans. Particle size distributions of Av horizons are typically bimodal with primary modes of very fine silt and fine sand, suggesting that the horizon matrix is derived from multiple sources. Here we conduct detailed chemical and physical analysis of both Av horizon soil samples and potential sources of aeolian sediment to better constrain the relative contributions of dust associated with the development of Av horizons. Geochemical data from both sand (125-250 µm) and silt (2-32 µm) fractions in Av horizons and potential dust sources in the eastern Mojave Desert and western Sonora Desert, USA, point to large contributions from nearby sources including distal alluvial fans and washes, and comparably lower contributions from regional sources such as playas. The silt mode is derived from suspension transport of dust, and the fine sand mode is derived from saltating sand. The desiccation of pluvial lakes in the Mojave Desert is commonly believed to have driven episodes of aeolian activity, contributing to sand dunes and Av horizon formation. We propose that alluvial fans and washes are underappreciated as desert dust sources and that pulses of dust from late Pleistocene and Holocene alluvial fans dwarfed pulses of dust from desiccating pluvial lakes in the eastern Mojave Desert.

Sweeney, Mark R.; McDonald, Eric V.; Markley, Christopher E.

2013-03-01

403

Desert pavement study at Amboy, California  

NASA Astrophysics Data System (ADS)

Desert pavement is a general term describing a surface that typically consists of a thin layer of cm-sized rock fragments set on top of a layer of finer material in which no fragments are found. An understanding of desert pavement is important to planetary geology because they may play a major role in the formation and visibility of various aeolian features such as wind streaks, which are important on Mars and may be important on Venus. A field study was conducted in Amboy, California to determine the formation mechanism of desert pavements. The probable sequence of events for the formation and evolution of a typical desert pavement surface, based on this experiment and the work of others, is as follows. Starting with a layer of surface material consisting of both fine particles and rock fragments, aeolian deflation will rapidly erode the surface until an armored lag is developed, after which aeolian processes become less important. The concentration of fragments then slowly increases as new fragments are brought to the surface from the subsurface and as fragments move downslope by sheet wash. Sheet wash would be responsible for removing very fine particles from the surface and for moving the fragments relative to one another, forming interlocks.

Williams, S.; Greeley, R.

1984-04-01

404

The Desert Tortoise: A Delicate Balance  

NASA Technical Reports Server (NTRS)

This award winning program looks at the efforts to preserve the desert tortoise in and around the Edwards Air Force Base, CA area. It also explains what people should do if they come in contact with a tortoise. This video was produced in cooperation with Edwards Air Force Base.

1992-01-01

405

Nonlinear spectral mixing in desert vegetation  

Microsoft Academic Search

Linear mixing models are widely used in terrestrial remote sensing, with the errors in these models being often attributed to “nonlinear” mixing. Nonlinear mixing refers to the interaction of light with multiple target materials. Reflectance data from creosote bush in the Manix Basin of the Mojave Desert is used to show the existence and importance of nonlinear mixing in and

Terrill W. Ray; Bruce C. Murray

1996-01-01

406

Path Integration in Desert Ants, Cataglyphis fortis  

Microsoft Academic Search

Foraging desert ants, Cataglyphis fortis, continually keep track of their own positions relative to home--i.e., integrate their tortuous outbound routes and return home along straight (inbound) routes. By experimentally manipulating the ants' outbound trajectories we show that the ants solve this path integration problem not by performing a true vector summation (as a human navigator does) but by employing a

Martin Muller; Rudiger Wehner

1988-01-01

407

Today's Vibrant, Far from Deserted, Academic Libraries  

Microsoft Academic Search

The inflammatory title, if not the text, of Scott Carlson's November, 2001 article in The Chronicle of Higher Education, “The Deserted Library: As Students Work Online, Reading Rooms Empty Out-Leading Some Campuses to Add Starbucks,” presented a misleading view of today's college and undergraduate libraries. This guest editorial rebuts Carlson's argument and cites evidence to support a different view of

Lynn Scott Cochrane

2002-01-01

408

Desert Research and Technology Studies 2008 Report  

NASA Technical Reports Server (NTRS)

During the last two weeks of October 2008, the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) Advanced Extravehicular Activity (AEVA) team led the field test portion of the 2008 Desert Research and Technology Studies (D-RATS) near Flagstaff, AZ. The Desert RATS field test activity is the year-long culmination of various individual science and advanced engineering discipline areas technology and operations development efforts into a coordinated field test demonstration under representative (analog) planetary surface terrain conditions. The 2008 Desert RATS was the eleventh RATS field test and was the most focused and successful test to date with participants from six NASA field centers, three research organizations, one university, and one other government agency. The main test objective was to collect Unpressurized Rover (UPR) and Lunar Electric Rover (LER) engineering performance and human factors metrics while under extended periods of representative mission-based scenario test operations involving long drive distances, night-time driving, Extravehicular Activity (EVA) operations, and overnight campover periods. The test was extremely successful with all teams meeting the primary test objective. This paper summarizes Desert RATS 2008 test hardware, detailed test objectives, test operations, and test results.

Romig, Barbara; Kosmo, Joseph; Gernhardt, Michael; Abercromby, Andrew

2009-01-01

409

Desert pavement study at Amboy, California  

NASA Technical Reports Server (NTRS)

Desert pavement is a general term describing a surface that typically consists of a thin layer of cm-sized rock fragments set on top of a layer of finer material in which no fragments are found. An understanding of desert pavement is important to planetary geology because they may play a major role in the formation and visibility of various aeolian features such as wind streaks, which are important on Mars and may be important on Venus. A field study was conducted in Amboy, California to determine the formation mechanism of desert pavements. The probable sequence of events for the formation and evolution of a typical desert pavement surface, based on this experiment and the work of others, is as follows. Starting with a layer of surface material consisting of both fine particles and rock fragments, aeolian deflation will rapidly erode the surface until an armored lag is developed, after which aeolian processes become less important. The concentration of fragments then slowly increases as new fragments are brought to the surface from the subsurface and as fragments move downslope by sheet wash. Sheet wash would be responsible for removing very fine particles from the surface and for moving the fragments relative to one another, forming interlocks.

Williams, S.; Greeley, R.

1984-01-01

410

DEVELOPMENT STRAINS ON AUSTRALIA'S GREATEST DESERT RIVER  

Microsoft Academic Search

Desert rivers are full of life geared towards highly variable flows. Cooper Creek is probably the longest and most important dryland river in Australia and one of the largest internally draining catchments in the world. Long dry periods (busts) are punctuated by floods of high productivity (boom periods). Highly variable flows are the antithesis of requirements for regular water for

Richard T. Kingsford

411

Microflora in soils of desert regions  

NASA Technical Reports Server (NTRS)

Desert soil samples, collected using aseptic techniques, are low in organic matter and cation exchange capacity. Aerobic and microaerophilic bacteria are most abundant, next are algae and molds. Chemical and physical properties are determined by standard procedures, including the Kjeldahl method and the use of Munsell soil color charts.

Cameron, R. E.

1970-01-01

412

Characteristics and Influential Factors of Food Deserts.  

National Technical Information Service (NTIS)

USDA's Economic Research Service previously identified more than 6,500 food desert tracts in the United States based on 2000 Census and 2006 data on locations of supermarkets, supercenters, and large grocery stores. In this report, we examine the socioeco...

M. Ver Ploeg P. Dutko T. Farrigan

2012-01-01

413

Metagenomes from the saline desert of kutch.  

PubMed

We provide the first report on the metagenomic approach for unveiling the microbial diversity in the saline desert of Kutch. High-throughput metagenomic sequencing of environmental DNA isolated from soil collected from seven locations in Kutch was performed on an Ion Torrent platform. PMID:24831151

Pandit, A S; Joshi, M N; Bhargava, P; Ayachit, G N; Shaikh, I M; Saiyed, Z M; Saxena, A K; Bagatharia, S B

2014-01-01

414

Anticancer attributes of desert plants: a review.  

PubMed

The ever-increasing emergence of the resistance of mammalian tumor cells to chemotherapy and its severe side effects reduces the clinical efficacy of a large variety of anticancer agents that are currently in use. Thus, despite the significant progress in cancer therapeutics in the last decades, the need to discover and to develop new, alternative, or synergistic anticancer agents remains. Cancer prevention or chemotherapy based on bioactive fractions or pure components derived from desert plants with known cancer-inhibiting properties suggests promising alternatives to current cancer therapy. Plants growing on low nutrient soils and/or under harsh climatic conditions, such as extreme temperatures, intense solar radiation, and water scarcity, are particularly susceptible to attack from reactive oxygen species and have evolved efficient antioxidation defense systems. The many examples of desert plants displaying anticancer effects as presented here indicates that the same defensive secondary metabolites protecting them against the harsh environment may also play a protective or a curative role against cancer, as they also do against diabetes, neurodegenerative, and other acute and chronic diseases. The present review highlights a plethora of studies focused on the antineoplastic properties of desert plants and their prinicipal phytochemicals, such as saponins, flavonoids, tannins, and terpenes. Although many desert plants have been investigated for their antitumor properties, there are many that still remain to be explored - a challenge for the prospective cancer therapy of the future. PMID:22217921

Harlev, Eli; Nevo, Eviatar; Lansky, Ephraim P; Lansky, Shifra; Bishayee, Anupam

2012-03-01

415

Metagenomes from the Saline Desert of Kutch  

PubMed Central

We provide the first report on the metagenomic approach for unveiling the microbial diversity in the saline desert of Kutch. High-throughput metagenomic sequencing of environmental DNA isolated from soil collected from seven locations in Kutch was performed on an Ion Torrent platform.

Pandit, A. S.; Joshi, M. N.; Bhargava, P.; Ayachit, G. N.; Shaikh, I. M.; Saiyed, Z. M.; Saxena, A. K.

2014-01-01

416

An Ecosystem Services Framework for Desert Landscapes  

EPA Science Inventory

Governments, tribal leaders and citizens of the deserts in North America are facing unprecedented pressures from population growth and climate change. The dominant environmental and economic issue is to ensure that people have access to clean water and sanitation while vital ecos...

417

Desert Culture Area. Native American Curriculum Series.  

ERIC Educational Resources Information Center

One in a series of Native American instructional materials, this booklet introduces elementary students to the history and culture of the Navajo, Pueblo, and other Indian tribes of the southwest desert. Written in simple language, the booklet provides background information, activities, legends, and illustrations. Topics include the climate of the…

Ross, Cathy; Fernandes, Roger

418

Desert vegetation and timing of solar radiation  

Microsoft Academic Search

Timing and amount of solar radiation were examined as factors influencing the distribution of seven perennial plants on a small mountain located in the Chihuahuan Desert. Average direct beam solar radiation fluxes at differing times throughout the day and year were estimated with computer calculations. Principal components analysis was used to reduce the number of solar radiation parameters and include

J. C. Waltona; F. Martinez-Gonzalez; R. Worthington

2005-01-01

419

Atmospheric science: Desert dust and monsoon rain  

NASA Astrophysics Data System (ADS)

The climate regimes of monsoon regions and deserts are connected. Satellite data and numerical experiments reveal that an increase in dust aerosol loading over the Arabian Sea and West Asia can lead to enhanced summer monsoon rainfall over central India on timescales of days to weeks.

Lau, William

2014-04-01

420

Managing Wholesale Nurseries in the Desert  

Microsoft Academic Search

This study reports the management practices and strategies of wholesale nursery operations in Arizona. In this desert environment near large California competitors, Arizona firms attempt to differentiate their products and develop market niches as competitive strategies. Xeriscape using low-water-use plants is an evolving specialty product of the industry. Future industry and public education concerning xeriscape is necessary to strengthen this

Paul N. Wilson; Julie P. Leones

1995-01-01

421

Satellites Reveal How Rare Elephants Survive Desert  

NSDL National Science Digital Library

This National Geographic article describes how a genetically and geographically distinct species of elephants survives in the desert. The Mali elephants endure by following a circular migratory path that goes from water-hole to water-hole, following rainfall as it occurs.

Mayell, Hillary; News, Natioanl G.

422

Safe transport of radioactive materials in Egypt  

NASA Astrophysics Data System (ADS)

In Egypt the national regulations for safe transport of radioactive materials (RAM) are based on the International Atomic Energy Agency (IAEA) regulations. In addition, regulations for the safe transport of these materials through the Suez Canal (SC) were laid down by the Egyptian Atomic Energy Authority (EAEA) and the Suez Canal Authority (SCA). They are continuously updated to meet the increased knowledge and the gained experience. The technical and protective measures taken during transport of RAM through SC are mentioned. Assessment of the impact of transporting radioactive materials through the Suez Canal using the INTERTRAN computer code was carried out in cooperation with IAEA. The transported activities and empty containers, the number of vessels carrying RAM through the canal from 1963 to 1991 and their nationalities are also discussed. The protective measures are mentioned.A review of the present situation of the radioactive wastes storage facilities at the Atomic Energy site at Inshas is given along with the regulation for safe transportation and disposal of radioactive wastes

El-Shinawy, Rifaat M. K.

1994-07-01

423

Central corneal thickness in southern Egypt.  

PubMed

The study aimed to determine mean central corneal thickness (CCT) in a southern Egyptian population according to gender and age using ultrasonic pachymetry and to compare these CCT measurements to different populations. A prospective, observational, consecutive case series of 4,368 non-glaucomatous subjects (emmetropes and myopes) aged 16-70 years was carried out from August 2010 to March 2013 at the outpatient ophthalmology clinic in Sohag University Hospital and the Laser Vision Center in Sohag City, Egypt. Refraction, keratometry, slit-lamp examination, and intraocular pressure (IOP) measurements were obtained for all subjects. CCT was measured by ultrasonic pachymetry. The average CCT was 530.06 ± 38.03 ?m. Average CCT was 532.6 ± 33.3 ?m in emmetropes, 531.5 ± 31.3 ?m in myopes <6 diopters (D), 531.1 ± 31.4 ?m in myopes >6 D and 533 ± 33 ?m in hyperopes, with no statistically significant difference between the groups. There was a statistically significant difference in CCT between age groups and gender. There was a strong correlation between CCT and IOP among the non-glaucomatous population. CCT was found to be lower in Egyptians than in Caucasian, Hispanic, and Japanese populations but comparable to African and African American populations. PMID:24272277

Mostafa, Engy Mohamed

2014-08-01

424

Implications of terrain movements in Egypt  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to study the causes of localized terrain movements in Egypt. The motivation behind this research has been the vast progress in constructing huge engineering structures (dams, bridge,, tall buildings, etc.) as well as extending the urban activities in many new cities. These must be properly studied to ensure their safety versus their cost and other economic factors. In addition, the recent tendency is towards building nuclear power stations whose locations must be carefully investigated against the hazard and danger of inevitable atomic leakage, especially in the case of seismically active regions. Also the discovery of new oil wells and mines and the effects of future depletion require considerable attention from qualified investigators. The relative tectonic movements of North Africa and Southern Europe, the seismic activities around the Alexandria region, the presence of faults related to the region of the High Dam and its reservoir in Aswan, the erosion of the banks of the River Nile and its islands as well as coastal lines along the Mediterranean and the Red Sea, and the deformation and damage to large buildings in the Cairo area are examined here as a few examples of the implications of the earth's deformations within Egyptian territory. Strong recommendations are made concerning the necessity of studying and monitoring the terrain movements in the areas where new cities, large engineering constructions and power plants are planned to be erected.

Nassar, Mohamed M.

1988-10-01

425

Optimum Geoid Fitting Technique for Egypt  

NASA Astrophysics Data System (ADS)

The paper introduces a proposed geoid fitting technique of the physically determined geoid to the GPS/leveling derived geoid in Egypt. First the possible blunders of the available GPS benchmarks are eliminated. The technique works on the basis of the absolute geoid difference (physical geoid minus GPS/leveling derived geoid). The proposed geoid fitting technique selects a number of few best suited GPS benchmarks using an automatic optimization scheme. The influence of each GPS point on the remaining GPS points is computed using the least-squares prediction technique. The GPS point having the minimum influence on the remaining points is added to the subset of the GPS points to be used for the external checking. This step is repeated iteratively, and each time the number of the available GPS is decreased by one, till an acceptable limit of the influence of the GPS points on the remaining ones. This limit has been set for the current investigation to couple of decimeters. The output of this scheme is two subsets. The first subset comprises the points having the minimum influence, which represents the subset used for the external check of the geoid quality. The second subset contains the GPS points used for the geoid fitting process. A practical test of the proposed technique is given and the obtained internal and external geoid accuracies are widely discussed.

Abd-Elmotaal, Hussein; Makhloof, Atef

2014-05-01

426

Western Canada  

SciTech Connect

In 1980, a third successive all-time drilling record was set in western Canada, with 8865 wells being drilled, up 20% since 1979. Exploratory drilling increased 30%, to 3744 wells, and development drilling increased 14%, to 5121 wells. The exploratory success rate increased to 66% in 1980, based on 1017 oil discoveries and 1463 gas discoveries. The development success rate increased marginally to 89%, with 1774 oil discoveries and 2778 gas discoveries. Average well depth increased in all four western provinces, and total land sales reached the record $1 billion mark in Alberta and a record $78 million in Saskatchewan. British Columbia land sales declined slightly to $181 million. Alberta drilling activity continued in the deeper portions of the Alberta basin and foothills, with major gas discoveries at Hanlan, Big Mountain, Blackstone, and Elmworth. Significant oil discoveries were made in the West Pembina Nisku pinnacle reefs, in the Upper Devonian at Del Bonita and Eaglesham, and in the Lower Cretaceous glauconite river channels in southern Alberta between Countess and Grand Forks. British Columbia successes occurred as the Elmworth Deep Basin play spilled over into British Columbia with gas discoveries at Tupper and Steeprock. Gas finds were also made at West Sierra and Murray. The Arctic Islands continued to yield the largest discoveries. Two major successes occurred in the Beaufort Sea, in an oil and gas discovery by Esso at Issungnak and a reentry oil discovery by Dome at Tarsuit. However, 1980 will especially be remembered for the introduction of the federal government's National Energy Program during October, with new taxes on revenue, lower than expected wellhead price increases, and major emphasis on increasing Canadian ownership and self-sufficiency. Industry and provincial government reaction was highly critical, and a major downturn in exploration is expected in western Canada in 1981. 3 figures, 8 tables.

Hay, P.W. (Canadian Stratigraphic Service Ltd., Calgary, Alberta); Robertson, D.C.

1981-10-01

427

Modeling the spatial spread of Rift Valley fever in Egypt.  

PubMed

Rift Valley fever (RVF) is a severe viral zoonosis in Africa and the Middle East that harms both human health and livestock production. It is believed that RVF in Egypt has been repeatedly introduced by the importation of infected animals from Sudan. In this paper, we propose a three-patch model for the process by which animals enter Egypt from Sudan, are moved up the Nile, and then consumed at population centers. The basic reproduction number for each patch is introduced and then the threshold dynamics of the model are established. We simulate an interesting scenario showing a possible explanation of the observed phenomenon of the geographic spread of RVF in Egypt. PMID:23377629

Gao, Daozhou; Cosner, Chris; Cantrell, Robert Stephen; Beier, John C; Ruan, Shigui

2013-03-01

428

Education in Egypt and Egyptian response to eclipses  

NASA Astrophysics Data System (ADS)

Astronomy and space science educations started in Egypt at the university level since 1939 at Department of Astronomy and Meteorology, Cairo University. Undergraduate and graduate education in Egypt will be discussed in this work. About 15 students yearly obtain their PhD degrees in Astronomy from the Egyptian universities. Seven International groups under my supervision have done the total solar Eclipse observations that took place on 29 March 2006, in El-Saloum (Egypt). The results of observations and photos will be discussed. Egyptian-French group have done the total solar eclipse observations that took place on 25 February 1952 in Khartoum by using Worthington Camera. The research groups of Astrophysics in Cairo University and Helwan observatory are interested in the fields of solar physics, binary stars, celestial mechanics, interstellar matter and galaxies. Most of the researches have been published in national scientific journals, and some of them were published in International Journals.

Hady, A.

2006-08-01

429

Assessment of the long-term hydrologic impacts of Lake Nasser and related irrigation projects in southwestern Egypt.  

SciTech Connect

A two-dimensional groundwater flow model was constructed to investigate the long-term hydrologic impacts of Lake Nasser and the major land reclamation projects that use excess lake water in southwest Egypt. Egypt constructed (1964-1971) the Aswan High Dam, creating the Lake Nasser reservoir (length: 500 km; average width: 12 km) and is constructing the Tushka Canal to channel 5.0x10{sup 9} m{sup 3}/yr of Lake Nasser water to reclaim 0.5x10{sup 6} acres of desert lands. The model, constrained by regional-scale groundwater flow and near-lake head data, was successfully calibrated to temporal-observation heads from 1970 to 2000 that reflect variations in lake levels. Predictive analyses for the subsequent 50-yr period were conducted by employing the calibrated model. Simulations of long-term effects, beyond year 2000, of Lake Nasser on recharge and temporal groundwater head (base case scenario) show that recharge from the lake will continue at a much slower rate than during the 30-yr period of 1970-2000 (with approximately 86% reduction in 30-yr recharge). The modest projected pumping and injection activities in the study area are not expected to cause major deviation in the overall head distribution compared to the base case scenario. The investigation of effects of the new irrigation land development on the Nubian aquifer indicated that many of the proposed irrigation areas, especially those with small aquifer thickness, will become fully saturated with introduced water, resulting in potential flooding and salinization.

Kim, J.; Sultan, M.; Environmental Research

2002-05-10

430

Does current precipitation play a role in the recharge of groundwater in the deserts of northern China?  

NASA Astrophysics Data System (ADS)

Arid and semi-arid areas account for more than one third of the Chinese landmass and are distributed over elevations ranging from 155 m below sea level to over 5000 m above sea level. The most typical landscapes of this vast and diverse region are sand seas in arid and sandy lands in the semiarid zones. The widely cited value about mean annual evaporation in the deserts of northern China is between ca. 1400 to 3000 mm / year in general and between 3000 and 3800 mm / year in dune fields. Under such a framework modern precipitation would be meaningless to the recharge of groundwater. Our new estimate, based on the weather data from the last four decades, suggests, however, there is a clear overestimate of the evaporation rate in the earlier data. In a sand sea like the Badain Jaran Desert in the western Inner Mongolia, our calculation using a modified Penman equation shows that the mean annual evaporation is ca. 1000 mm from lakes and ca. 100 mm from the land surface. Our estimate is consistent with a new analysis showing that only ca. 10% of chloride in the soluble salts of aeolian sands in western Inner Mongolia comes directly from rainfall while 90% of chloride in these salts is deposited directly by dust accumulation (dry deposition). Limited, short-term experiment with large evaporation ponds supports our new estimate also. Provided that the new estimate tells the truth, we can further conclude that the current precipitation - ca. 100 mm in the southeast of the Badain Jaran Desert - plays a significant role in the recharge of the groundwater that directly feeds a large number of "small" desert lakes in this region. The existence of measurable tritium in the shallow ground water samples from the margins of these desert lakes reconfirms the importance of modern precipitation in the recharge of groundwater as well.

Yang, Xiaoping

2014-05-01

431