Comparison of Methods Used to Delineate Capture Zones of Wells: 2. Stratified-Drift Buried-Valley Aquifer   总被引：1，自引：0，他引：1  

Abraham E. Springer  E. Scott Bair 《Ground water》1992,30(6):908-917

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Petrology of a ferruginous hornfels from Riekensglück,Harz Mountains,Germany     

K. Abraham  W. Schreyer 《Contributions to Mineralogy and Petrology》1973,40(4):275-292

The hornfels first described by Ramdohr (1927) contains the rare, if not unique, mineral assemblage olivine-cordierite-spinel-garnet-gedrite-biotite(-tourmaline)-FeTi oxides. Mieroprobe analyses of the constituting phases show that their Fe/(Fe+Mg)-ratios increase in the order (tourmaline-) cordierite-biotite-gedrite-olivine-garnet-hercynite-rich spinel. On the basis of the experimental results of Hsu and Burnham (1969) in the system Fe-O-MgO-Al₂O₃-SiO₂-H₂O the metamorphic history of the hornfels is subdivided into an earlier high-temperature stage 1 characterized mainly by the assemblage olivine-cordierite-spinel, and a subsequent, lower-temperature stage 2, in which the additional phases garnet and gedrite grew as porphyroblasts and equilibrated with the other phases. At an estimated mean confining pressure of 500 bars for both hornfels stages the temperatures during stage 1 may have ranged from 600° to about 800° C, whereas during stage 2 only some 550–580° C were attained. It is possible that these two metamorphic stages are due to the consecutive intrusions, first of the gabbroic and then of the granitic magmas.  相似文献   

Occurrence and Resistance of Pathogenic Bacteria Along the Tietê River Downstream of São Paulo in Brazil     

Wolf-Rainer Abraham  Alexandre José Macedo  Luiz Humberto Gomes  Flavio C. A. Tavares 《洁净——土壤、空气、水》2007,35(4):339-347

The load of pathogenic bacteria, their fate and their dangerousness in the Tietê River were assessed along 100 km starting from the city of São Paulo, Brazil. The data were compared with those from two German rivers. High loads of pathogens were found in the Tietê River near the city of São Paulo (Escherichia coli O157:H7, Shigella flexneri, and Shigella boydii), which were absent 30 km downstream of São Paulo. The antibiotic resistances observed in the Tietê river were rather low and decreased after the major input in São Paulo to significantly lower levels about 30 km downstream. While the Brazilian isolates were more susceptible for ampicillin than the German ones, the reverse was observed for gentamycin. For optimal control of infections in humans critical areas where these bacteria survived longer and their elimination mechanisms should be identified as well as the extent and the origin of antibiotic resistance should be determined.  相似文献   

The shift of ravi river and the geomorphological features along its course in amritsar and gurdaspur districts of punjab     

Abraham Thomas  PK Sharma 《Journal of the Indian Society of Remote Sensing》1998,26(1-2):57-68

Satellite remote sensing technique can be effectively utilised in mapping and monitoring the river course changes and associated geomorphological features. Ravi river, flowing along the Indo-Pakistan border, has been in the limelight for its repeated flood havoc during monsoon and abrupt encroachment at some places in the Indian territory, where it was not flowing earlier. This river, meandering in zig-zag fashion along the International boundary in Amritsar and Gurdaspur districts of Punjab, poses perennial threats to the nations’s economy due to extensive destruction happening every year. An attempt has been made to map the shift of this river and the associated geomorphological features along its course using the Indian Remote Sensing Satellite data (IRS-IA and IB LISS-IIFCC) of the period 1991–1993 and the Survey of India topographic sheets of the period 1972–1973. The study shows that there has been drastic changes in the course of Ravi during a span of 20 years due to human activities along its course. The river has shifted its course considerably towards India since its topography is against it. River training structures/bundhs, built by the neighbouring country, across and very near to the earlier river course has been the main reason for this drastic shifting. It is estimated that such massive structures could turn the river course towards India by atleast 1 to 5 km in the border districts of Punjab. This shifting of Ravi along international border poses a serious threat to the Nation’s defence system.  相似文献   

Paragenesis of “box-work geodes”, Tampa Bay, Florida     

Richard N. Strom  Sam B. Upchurch  Abraham Rosenzweig 《Sedimentary Geology》1981,30(4):275-289

An unusual suite of silicified rocks was excavated during a recent harbour-deepening project in Tampa Bay, Florida. These rocks, which we have termed “box-work geodes”, are composed of convoluted, intersecting silica walls enclosing cavities which are either voids or filled with relatively pure monoclinic palygorskite. The “box-work geodes” are interpreted as having formed in shallow lagoonal environments, similar to the Coorong Lagoon of South Australia. Synaeresis of syngenetic palygorskite was followed by opal deposition and case hardening of the material. Subsequent chemical deposition of chalcedony, megacrystalline quartz, barite, and calcite on the void facing walls indicates an open chemical system.

The existence of opal saturated lagoons, as inferred from the “box-work geodes”, suggests that much of the replacement chert, porcelanite, and silicified fossils in the Tertiary deposits of peninsular Florida formed in the shallow subsurface. Subsequent weathering of carbonates and clays not encapsulated in the box works has resulted in formation of a green montmorillonite residual clay bed.  相似文献   

On the role of the Asian monsoon in the angular momentum and kinetic energy balances of the tropics     

Abraham H. Oort  Paul H. Chan 《Pure and Applied Geophysics》1977,115(5-6):1167-1186

The balance conditions of relative angular momentum and time-mean kinetic energy and their annual variations are studied for the Northern Hemisphere tropical belt. The belt is divided into two roughly equal size parts, the monsoon and the extramonsoon regions. The data used consist of all available daily rawinsonde reports from the world areological network for the two 5-year periods 1958–63 and 1968–73.In winter, the trade winds in the monsoon and extramonsoon regions are both sources of westerly relative angular momentum for the middle latitude circulation. However, it is found that the angular momentum gained in the extramonsoon region of the Tropics is mostly destroyed by a net southward flow of mass in that region, and becomes regenerated in the monsoon region by a net northward flow of mass there. This excess of angular momentum together with the angular momentum picked up locally in the monsoon region is almost all exported across its northern boundary. It is further found that in winter the Tropics are also an important source of mean kinetic energy for middle latitudes. Again almost all export of kinetic energy was found to take place across the northern boundary of the monsoon sector. Most of this energy must be generated through the pressure gradient term inside the monsoon region itself, the transformation from transient eddy kinetic energy being very small. The proper evaluation of the pressure gradient appears to be the main stumbling block in the present study, preventing us from estimating the generation and thereby, as a residual, the frictional dissipation in the two regions.In summer, the extramonsoon region remains a source of angular momentum, but the monsoon region with its surface westerlies acts as a sink, leading to a sharp reduction (and even a midsummer reversal) of the export into middle latitudes. Also the export of mean kinetic energy almost vanishes in summer, except for a small southward transfer across the equator. The calculations for two 5-year periods give very similar estimates and thereby show the reliability of the results.Parts of this paper were presented at the International Symposium on Monsoons, March 7–12, 1977 in New Delhi, India.  相似文献   

The correlation between the distribution of galaxies and 21-cm emission at high redshifts     

J. Stuart B. Wyithe  Abraham Loeb 《Monthly notices of the Royal Astronomical Society》2007,375(3):1034-1042

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The Use of Hydrogeochemical Patterns in Carbonate Sand and Sandstone Aquifers to Identify Intrusion and Flushing of Saline Water   总被引：4，自引：0，他引：4  

Abraham Mercado 《Ground water》1985,23(5):635-645

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Variations in the biomass of Antarctic krill (Euphausia superba) around the South Shetland Islands, 1996-2006   总被引：1，自引：0，他引：1  

Reiss  Christian S.; Cossio  Anthony M.; Loeb  Valerie; Demer  David A. 《ICES Journal of Marine Science》2008,65(4):497-508

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Precession and nutation in the η Carinae binary system: evidence from the X-ray light curve     

Z. Abraham  D. Falceta-Gonçalves 《Monthly notices of the Royal Astronomical Society》2010,401(1):687-694

It is believed that η Carinae is actually a massive binary system, with the wind–wind interaction responsible for the strong X-ray emission. Although the overall shape of the X-ray light curve can be explained by the high eccentricity of the binary orbit, other features like the asymmetry near periastron passage and the short quasi-periodic oscillations seen at those epochs have not yet been accounted for. In this paper we explain these features assuming that the rotation axis of η Carinae is not perpendicular to the orbital plane of the binary system. As a consequence, the companion star will face η Carinae on the orbital plane at different latitudes for different orbital phases and, since both the mass-loss rate and the wind velocity are latitude dependent, they would produce the observed asymmetries in the X-ray flux. We were able to reproduce the main features of the X-ray light curve assuming that the rotation axis of η Carinae forms an angle of  29°± 4°  with the axis of the binary orbit. We also explained the short quasi-periodic oscillations by assuming nutation of the rotation axis, with an amplitude of about  5°  and a period of about 22 days. The nutation parameters, as well as the precession of the apsis, with a period of about 274 years, are consistent with what is expected from the torques induced by the companion star.  相似文献