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51.
The effects of dry summer ambient temperature on some physiological and productive responses were studied in an exotic European breed (Holstein–Friesian) and a local zebu breed (Butana ecotype) of cattle in Sudan. Rectal temperature and respiration rate were positively correlated, and dry matter intake and milk yield were negatively correlated with variation in ambient temperature. However, significant adverse effects on high ambient temperature were only observed in the exotic breed. 相似文献
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Yasser F Salama Gouda I Abdel-Gawad Shaban G Saber Soheir H El-Shazly G. Michael Grammer Sacit Özer 《Arabian Journal of Geosciences》2016,9(20):755
The present study aims to provide carbon-isotope curves for the Cenomanian to Turonian rudist-dominated successions in north Sinai. The high-resolution carbon-isotope curves obtained from north Sinai sections provide new insight for calibrating the age of rudists as well as for evaluating the effects of the oceanic anoxic event 2 (OAE2) on rudist communities. The primary goals are (1) to provide a high-resolution sequence stratigraphic framework for the Cenomanian-Turonian succession, (2) to use rudist and ammonite biostratigraphic data to distinguish the stratigraphic levels of the rudist species, and (3) to integrate the chemostratigraphic (δ13C) profile and the rudist levels to improve the biostratigraphy based on the rudist distributions and the carbon-isotope data. The recognition of three ammonite zones through the Cenomanian-Turonian succession was utilized to identify four temporally significant rudist levels indicative of the Lower Cenomanian, Middle Cenomanian, Upper Cenomanian, and Middle Turonian, respectively. Most of the rudists occur in the highstand deposits of medium-scale sequences. Carbon- and oxygen-isotopic analyses were carried out on both rudists and surrounding carbonate units. Based on the variations in the carbon-isotope signals, 12 chronostratigraphic segments were identified in the studied sections. The Cenomanian carbon-isotope segments (C23–C30) were obtained from the Halal Formation at Gabal Yelleg and Gabal Maaza sections, while the Turonian segments (C30–C34) were measured from the Wata Formation at Gabal Yelleg section. The carbon-isotope record from the studied sections is consistent with the trends documented in previous studies of the Tethyan realm. The Cenomanian-Turonian boundary is placed at the onset of falling carbon-isotope values (δ13C) from 2.61 to ?0.25‰ in the upper part of OAE2 with the carbon-isotope segment C30 at Gabal Yelleg. The negative shift in δ13C values (C33) occurred in the Middle Turonian lowstand deposits characterizing the global sea level fall during this interval. 相似文献
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Structural Mapping of the Bentong‐Raub Suture Zone Using PALSAR Remote Sensing Data,Peninsular Malaysia: Implications for Sediment‐hosted/Orogenic Gold Mineral Systems Exploration
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The Bentong‐Raub Suture Zone (BRSZ) of Peninsular Malaysia is one of the major structural zones in Sundaland, Southeast Asia. It forms the boundary between the Gondwana‐derived Sibumasu terrane in the west and Sukhothai Arc in the east. The BRSZ is genetically related to the sediment‐hosted/orogenic gold deposits associated with the major lineaments in the Central Gold Belt of Peninsular Malaysia. In this investigation, the Phased Array type L‐band Synthetic Aperture Radar (PALSAR) satellite remote sensing data were used to map major geological structures in Peninsular Malaysia and provide detailed characterization of lineaments and curvilinear structures in the BRSZ, as well as their implication for sediment‐hosted/orogenic gold exploration in tropical environments. Major structural lineaments such as the Bentong‐Raub Suture Zone (BRSZ) and Lebir Fault Zone, ductile deformation related to crustal shortening, brittle disjunctive structures (faults and fractures) and collisional mountain range (Main Range granites) were detected and mapped at regional scale using PALSAR ScanSAR data. The major geological structure directions of the BRSZ were N–S, NNE–SSW, NE–SW and NW–SE, which derived from directional filtering analysis to PALSAR fine and polarimetric data. The pervasive array of N–S faults in the Central Gold Belt and surrounding terrain is mainly linked to the N–S trending of the Suture Zone. N–S striking lineaments are often cut by younger NE–SW and NW–SE‐trending lineaments. Gold mineralized trend lineaments are associated with the intersection of N–S, NE–SW, NNW–SSE and ESE–WNW faults and curvilinear features in shearing and alteration zones. Compressional tectonic structures such as the NW–SE trending thrust, ENE–WSW oriented faults in mylonite and phyllite, recumbent folds and asymmetric anticlines in argillite are high potential zones for gold prospecting in the Central Gold Belt. Three generations of folding events in Peninsular Malaysia have been recognized from remote sensing structural interpretation. Consequently, PALSAR satellite remote sensing data is a useful tool for mapping major geological structural features and detailed structural analysis of fault systems and deformation areas with high potential for sediment‐hosted/orogenic gold deposits and polymetallic vein‐type mineralization along margins of Precambrian blocks, especially for inaccessible regions in tropical environments. 相似文献
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Mallick Javed Salam Roquia Amin Ruhul Islam Abu Reza Md. Towfiqul Islam Aznarul Siddik Md. Nur Alam Alam G. M. Monirul 《Natural Hazards》2022,112(2):1633-1656
Natural Hazards - Understanding household disaster risk perception is crucial to formulate and apply disaster risk reduction strategies. Using survey data from 300 households from three highly... 相似文献
58.
Removal of cadmium and humic acid from aqueous solutions using surface modified nanozeolite A 总被引:2,自引:2,他引:0
H. R. Tashauoei H. Movahedian Attar Ph.D. M. M. Amin Ph.D. M. Kamali M. Nikaeen M. Vahid Dastjerdi M.Sc. 《International Journal of Environmental Science and Technology》2010,7(3):497-508
The sorption of cadmium and humic acids from aqueous solutions using surface-modified nanozeolite A has been investigated under various examination conditions. The morphology of untreated and treated nanozeolite was studied under scanning electron microscope and transmission electron microscope. Isotherms of cadmium adsorption onto surface-modified nanozeolite A were studied at different pH, solid to liquid ratio, adsorbate concentration and interaction time. Kinetic and equilibrium studies were conducted and the equilibrium data have been analyzed using Langmuir and Freundlich isotherm models. The study revealed that experimental results were in agreement with the Freundlich model. The Langmuir monolayer adsorption capacity was found to be 1666.67 g cadmium and 6.75 g humic acid per gram of modified nanozeolite A, which is higher than that of reported value for other zeolites. The sorption ability was enhanced by surface modification and reduction in size and enabled the zeolite to adsorb cadmium. The adsorption of cadmium and humic acid on nanozeolite was found to be the highest at pH 6 and 3, respectively. Results showed that solid to liquid ratio and pH are the most important factors for cadmium and humic acid removal, respectively. Effect of competitive ions was studied and results showed that there is no competition between cadmium and humic acid sorption and presence of these ions. 相似文献
59.
Measurements of radon contents of the exholved gas emanating from several hot water springs along the Western Coast of India are reported here. Concentration of radon in gas phase of individual springs varied in general, directly with the surface temperature of the water emerging from the respective springs, and showed little variation with time. Radon measurements were carried out continuously for about two years at two hot springs located at Ganeshpuri and Sathivali in the coastal area of Northern Maharashtra. The distant tremors did not cause any variation in the radon content. There was no marked local seismic activity during the period of observations, and the levels of radon stayed essentially constant. The measurements were also carried out at a hot spring in Assam, for about 8 months. These also did not show any significant variation; this period too lacked any marked local seismicity. 相似文献
60.
Isam E. Amin 《Environmental Geology》2005,47(4):558-564
Quantification of leakage is very important in the selection and design of the remediation systems of leaky aquifers that receive contaminated leakage. This is an approach for the calculation of leakage using only two slopes of time-drawdown data. These slopes represent before and after the start of leakage, and are applied to four examples. Results generally agree with those determined by the Hantush approach. Comparison of the two approaches, however, shows that the Hantush approach quantifies leakage using three aquifer parameters (transmissivity, storativity, and leakage factor), the value of which depend on the pumping test method used; it assumes constant hydraulic head in the aquifer supplying leakage, which may not be valid under field conditions; and it ignores differences between the viscosities of the leakage water and the aquifer water, which influence the leakage rate. The proposed approach is free from all three limitations. 相似文献