Biosecurity and the multiplication of crises in the Egyptian agri-food industry     

《Geoforum》2015

Through a case study of Egypt’s agri-food industry this paper examines biosecurity as a set of technologies, institutions, and practices that attempt to govern national agri-food industries and global agri-food trade by marrying a political economy perspective and an analysis of ‘nature–society relations’. Consistent with other agri-food industries in the global South, Egypt’s agri-food industry has undergone waves of corporate consolidation during the neoliberal period. By detailing the growth of the poultry industry and the endemic spread of HPAI H5N1 (avian flu), this paper presents an argument that the industry grew and consolidated through emergent and recurrent zoonotic and plant diseases, the management of which has been governed in part by biosecurity measures.  相似文献   

Serpentinized Peridotites at the North Part of the Wadi Allaqi District (Egypt): Implications for the Tectono-Magmatic Evolution of Fore-arc Crust   总被引：2，自引：0，他引：2  

Ahmed E.S. KHALIL  Mohamed A. OBEID  Mokhles K. AZER 《《地质学报》英文版》2014,88(5):1421-1436

The Neoproterozoic Allaqi-Heiani suture （800-700 Ma） in the south Eastern Desert of Egypt is the northernmost linear ophiolitic belt that defines an arc-arc suture in the Arabian- Nubian shield （ANS）. The Neoproterozoic serpentinized peridotites represent a distinct lithology of dismembered ophiolites along the Allaqi-Heiani suture zone. The alteration of peridotites varies, some contain relicts of primary minerals （Cr-spinel and olivine） and others are extremely altered, especially along thrusts and shear zones, with development of talc, talc-carbonate and quartz-carbonate. The fresh cores of the chromian spinels are rimmed by ferritchromite and Cr- magnetite. The fresh chromian spinels have high Cr# （0.62 to 0.79）, while Mg# shows wider variation （0.35-0.59）. High Cr# in the relict chromian spinels and Fo content in the primary olivines indicate that they are residual peridotites after extensive partial melting. The studied ophiolitic upper mantle peridotites are highly depleted and most probably underwent high degrees of partial melting at a supra-subduction zone setting. They can be produced by up to -20%-22% dynamic melting of a primitive mantle source. The mineralogical and geochemical features of the studied rocks reflect that the mantle peridotites of the north part of the Wadi Allaqi district are similar to the fore-arc peridotites of a supra-subduction zone.  相似文献   

Comparison of soil salinity and solute transport for different cultivated soil types in northeastern Egypt / Comparaison de la salinité du sol et du transport de solutés pour différents types de sols cultivés du nord-est de l'Egypte     

《水文科学杂志》2013,58(2):466-478

Abstract

The soil salinity distribution and solute transport properties of three different soil types were investigated and compared within a project area in northeastern Egypt. For this purpose, dye tracer experiments and salinity sampling were carried out. The resulting salinity maps showed that the soil salinity in the cultivated western site of the project area is 8–10 times higher than that in the cultivated eastern site. However, the cultivated soil displayed significantly lower salinity with higher uniformity as compared to the uncultivated soil. The preferential flow phenomenon was less apparent in the cultivated soil. This is mainly due to tillage which disrupts the structure of the soil so that deep cracks are no longer connected to the soil surface. This reduces the risk for groundwater contamination through preferential flow. The study showed that careful and continuous monitoring of the salinity status is needed now and in the future.  相似文献   

The effects of grazing on the endangered Sinai Thyme (Thymus decussatus) in a hyper-arid environment     

《Journal of Arid Environments》2013

Herbivores play a key role in determining plant community composition. Historically grazing has been deemed detrimental for plants, but recent theoretical and empirical studies suggest that grazing may in fact be beneficial. Grazing is more likely to improve primary productivity in areas with a grazing history, where the plants are adapted to tolerate grazing, and also in arid environments because water stress and grazing select for comparable plant traits. Sinai Thyme (Thymus decussatus) in the arid St Katherine Protectorate of South Sinai has high apparent mortality rates and poor condition, both of which have detrimental consequences for its associated herbivores, particularly the Critically Endangered Sinai Baton Blue (Pseudophilotes sinaicus) whose larval stage feeds exclusively upon this plant. One recent conservation action banned grazing but there has been no obvious improvement in the thyme with continued high mortality, and local Bedu claim that grazing is in fact advantageous for plant health. We carried out a factorial experiment that manipulated simulated grazing, fertilizing and watering of thyme. This showed no evidence of any negative response to grazing or that watering or fertilizing had any effect either, presumably their impact is smaller than the current inter-annual variability caused by climatic fluctuations.  相似文献   

New Tricks with Old Maps: Urban Landscape Change,GIS, and Historic Preservation in the Less Developed World     

《The Professional geographer》2013,65(3):361-373

This article presents a methodology for a more detailed investigation of urban landscape change in rapidly growing cities of the less developed world beyond typical macrolevel approaches. This research is an attempt to bridge the gap between traditional landscape analysis and geographic information science (GIS). The article presents the preliminary results from a pilot project in Zamalek, Egypt, highlighting the benefits and drawbacks of the two techniques. Rarely used to study the less developed world, these techniques are utilized to assess change within a portion of Cairo's urban landscape. Large-scale historic maps and high-resolution satellite imagery, combined with field attribute collection, are the major data sources in this applied landscape analysis. A motivating factor in the desire to examine landscape change at such a large scale is the need to create monitoring systems for historic preservation in cities of the less developed world.  相似文献   

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

Usama Massoud  Gad El Qady  Mohamed Metwaly  Fernando Santos 《Pure and Applied Geophysics》2009,166(4):701-719

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.  相似文献   

Thalassinoides in the Middle Miocene succession at Siwa Oasis,northwestern Egypt     

《Proceedings of the Geologists' Association. Geologists' Association》2017,128(2):222-233

At Siwa Oasis, the carbonate-rich Middle Miocene Marmarica Formation includes several firmground discontinuity surfaces, characterized by extensive burrow systems. These surfaces are confined to the boundary between the Oasis and Siwa Escarpment members in addition to several intraformational marine firmground discontinuities at several horizons within these two members. The marine trace fossils from all these discontinuities are represented mainly by the ichnogenus Thalassinoides. In all occurrences, Thalassinoides are characterized by a sharp erosional lower contact and grades upward into fossiliferous argillaceous limestone facies. Three Thalassinoides ichnospecies have been reported, including: Th. horizontalis Myrow, 1995, Th. suevicus (Rieth, 1932) and Th. paradoxicus (Woodward, 1830). They are mostly recorded as hypichnial/endichnial forms at the sole of fossiliferous argillaceous limestone facies. Rare exichnial occurrences are also recorded. Thalassinoides ichnospecies displayed considerable variations in their stratigraphic distribution, in addition to remarkable variations in their complexity and dimension. These variations are mostly reflecting environmental conditions prevailed during the trace-maker life. Paleoenvironmental interpretation of these burrows confirmed a well-oxygenated shallow marine environment with extremely slow or nearly nil rate of sedimentation.  相似文献   

The nature of gold-bearing fluids in Atud gold deposit,Central Eastern Desert,Egypt     

Amr Abdelnasser  Mustafa Kumral 《International Geology Review》2017,59(15):1845-1860

Electron microprobe analyses of gold and associated ore minerals as well as stable isotope analyses of sulphide and carbonate minerals were performed in order to determine the metal and fluid sources and temperature of the mineralizing systems to better understand the genesis of the Atud gold deposit hosted in the metagabbro–diorite complex of Gabal Atud (Central Eastern Desert, Egypt). The gold can be classified as electrum (63.6–74.3 wt.% Au and 24.6–26.6 wt.% Ag) and is associated with arsenopyrite and As-bearing pyrite in the main mineralization (gold-sulphides) phase within the main mineralized quartz veins and altered host rocks. Based on the arsenopyrite geothermometer, As-contents (29.3–32.7 atom%) in arsenopyrite point to deposition in the Log ?_S2 and T ranges of ?10.5 to ?5.5 and 305–450°C, respectively, during the main mineralizing phase. Based on the δ³⁴S isotopic compositions of the sulphides, they are originated from magmatic fluids in which the sulphur is either sourced directly from magma or remobilized from the magmatic rocks (gabbroic rocks). On the other hand, calcite formed from fluids having mainly magmatic mixed with variable metamorphic signatures based on its δ¹³C and δ¹⁸O values. This work concluded that the gold-bearing ores at Atud deposit have magmatic sources leaching from the country intrusive rocks during water/rock interactions then remobilized during a metamorphic event. Therefore, the Atud gold deposit is classified as an intrusion-related gold deposit, in which the gabbro–diorite host intrusion acted as the source of metals which were mobilized and deposited as a result of the effects of NW–SE shearing.  相似文献   

Palynological,palaeoenvironmental and sequence stratigraphical analyses of a Turonian-Coniacian sequence,Beni Suef Basin,Eastern Desert,Egypt: Implication of Pediastrum rhythmic signature     

《Marine and Petroleum Geology》2017

Sixteen samples from the “E” to “B” members of the Abu Roash Formation encountered in the Beni Suef Basin, Eastern Desert of Egypt were palynologically analyzed for palaeoenvironmental and sequence stratigraphic investigations. The integrated palynofacies and lithofacies analysis of the studied section indicates deposition of five alternating regressive and transgressive sequences in well-oxygenated, proximal shelf settings. The Abu Roash “E” and the upper “D” to the lower “C” members were deposited during pronounced regressive phases in oxic, shallow marginal marine settings. The upper “B” Member was deposited during a recurring regressive phase but of a lower magnitude in oxic, shallow inner neritic conditions. The lower “D” Member was deposited during a minor transgression phase in dysoxic, shallow inner neritic settings. While the upper “C” to the lower “B” section was deposited during a stronger transgressive episode in a relatively deep, inner neritic environment of prominent dysoxic conditions. This interchange in the depositional setting was documented by the pronounced and concurrent, cyclic nature of the freshwater algae, peridinioid dinoflagellate cysts, pteridophyte spores, and reworked sporomorphs with variable intensities. Their increasing and conversely their diminishing trends clearly reflect alternating regressive-transgressive periods of reduced and relatively normal salinity conditions, respectively. Overall, sedimentation of the studied Abu Roash section indicates a recurring rise in sea level, which accentuated during the earliest Santonian time.The analogous peaking in the Pediastrum signals with those of the pteridophyte spores and reworked taxa indicate a good connection between these Pediastrum signals and the pronounced fluviatile influxes of terrigenous sediments during regressive phases. Accordingly, this can be used to identify regressive sequence boundaries and hence the clastic reservoirs. Even with the small counts recorded herein, we believe high ratios of peridinioid/gonyalulacoid dinocysts are significantly paralleled by peaking signals of freshwater algae and regressive sedimentation phases. This must be preliminary documented here. Probably future palynological studies will be able to fully interpret and address this important Pediastrum rhythmic event in different sequence stratigraphic settings.The palynological parameters, age controlled sporomorph marker taxa, lithology, and gamma ray data were used to differentiate the Abu Roash members into three distinctive 3rd order depositional sequences (AR SQ1, AR SQ2, and AR SQ3). These sequences match well with the global stratigraphic sequences Tu 3, Tu 4, and Co 1 and connect the local rise in sea level to the global eustatic sea level rise.  相似文献   

High and low temperature alteration of uranium and thorium minerals, Um Ara granites, south Eastern Desert, Egypt     

Hamdy H. Abd El-Naby   《Ore Geology Reviews》2009,35(3-4):436-446

The Um Ara area, in the south Eastern Desert of Egypt contains a number of uranium occurrences related to granitic rocks. U-rich thorite, thorite and zircon are the main primary uranium- and thorium-bearing minerals found in mineralized zones of the Um Ara alkali-feldspar granites; uranophane is the most common secondary uranium mineral. U-rich thorite contains blebs of galena, has rims of uranophane and contains inclusions of Zr-rich thorite. Electron probe microanalysis (EPMA) provides an indication of a range of solid solution between thorite and zircon, in which intermediate phases, such as Th-rich zircon and Zr-rich thorite, were formed. These phases have higher sum of all cations per formula (2.05 to 2.06 apfu, for 4 oxygen atoms) than that of ideal thorite and zircon. This is attributed to the presence of substantial amount of interstitial cations such as Ca, U and Al in these phases. Some zircon grains are stoichiometric in composition, other altered grains display lower SiO₂ and ZrO₂ contents. Enrichment of Th and U in altered zircon preferentially involves coupled substitution (Ca²⁺ + (Th,U)⁴⁺ ↔ 2Zr⁴⁺ + 2Si⁴⁺), implying that significant U and Th may enter the Zr and Si position in zircon. Negative correlation of Zr vs. Hf and Al may indicate that Hf and Al have been introduced to the zircon during later fluid alteration rather than during the primary magmatic event. A two-stage metallogenetic model is proposed for the alteration processes and origin of U- and Th-bearing minerals in the Um Ara alkali-feldspar granite: 1) the first stage was dominated by hydrothermal alteration and accompanied by albitization, k-feldspathization, desilicification, chloritization, hematitization, silicification, argillization, fluoritization and corrosion of primary U-bearing minerals. Solid-solution between thorite and zircon occurred during this stage. The second stage occurred at the near-surface profile where circulating meteoric water played an important role in mobilizing the early formed primary U-bearing minerals. Uranium was likely transported as a calcium uranyl carbonate complexes. When these complexes lost their stabilities by precipitation of calcite, they decomposed in the presence of silica to form uranophane.  相似文献