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561.
The use of a cosmic potential in relativistic cosmology is criticized. It is pointed out that the energetic closure of the Universe follows from general relativity and from quantized superspace cosmology without the introduction of the cosmic potential.  相似文献   
562.
Summary Daily 200-hPa relative vorticity data have been used to study the dominant patterns related to the cyclonic vortices over the South Atlantic Ocean in the vicinities of northeast Brazil, during the 1980–1989 period. Reference modes were obtained through empirical orthogonal function (EOF) analysis of the 200-hPa filtered vorticity anomalies over northeast Brazil, considering all the southern hemisphere (SH) summers within the study period. The amplitude time series of the first reference mode, separately for each SH summer, was correlated with the corresponding filtered vorticity anomalies in a larger area extending from 20°N to 40°S and between 120°W and 20°W. The correlation patterns feature a wave-like structure along eastern South America, with three main centers: the first one, over the South Atlantic off the northeast Brazil coast, is associated with the cyclonic vortices; the second one, over eastern Brazil, represents the corresponding anomalously amplified ridges; and the third one, over southern Brazil/Uruguay, is related to the equatorward incursions of midlatitude upper level troughs. This wave-like pattern is consistent with the vortex formation mechanism suggested in previous works. Another wave-like pattern southwest-northeast oriented is evident over the tropical southeastern Pacific, for some years. The internannual variability of these patterns is discussed in this paper.With 9 Figures  相似文献   
563.
The Taiwan Strait region has many miles of coastline, and the Taiwan Straits Tunnel (TST) project faces many potential pollution problems as construction proceeds through sensitive areas. Conventional approaches for pollution mitigation require further examination. The recent development of nanoscale particle technology has shown distinct advantages for contaminant attenuation and ground improvement. This paper is focused on trace metals and is part of the overall effort to develop the nanoscale particle technology. Trace metals in ground and surface waters represent a continued threat to human and ecological health. One of the difficulties in removing toxic concentrations of trace metals from solution is the variable oxidation state and amphoteric nature of multiple constituents. In particular, while cationic metals (e.g., Pb2+, Cd2+, Ni2+) may be rendered less mobile under high pH conditions, anionic metals (e.g., AsO43-, CrO42-, SeO42-)may become more mobile. The objective of this research was to evaluate the sorption of both cationic and anionic trace elements, including arsenic (As), cadmium (Cd), chromium (Cr) and selenium (Se) under batch conditions. Mixtures of a local residual soil were tested alone and in combination with lime and zero valent iron. It was hypothesized that lime would raise the pH and precipitate positively charged metals while zero valent iron would create reducing conditions favorable to the immobilization of negatively charged metals. Results indicate that the use of lime and/or zero valent iron can increase the sorption capacity of soil. Compared to the baseline soil, sorption capacity increased with addition of lime for arsenic and cadmium while it decreased for chromium and selenium. In the case of zero valent iron addition, sorption capacity increased for cadmium, chromium and selenium, while showing no change for arsenic. When both lime and zero valent iron were used, the sorption capacity increased for all metals tested. These results suggest that the combined use of lime and zero valent iron may serve as an alternative treatment technology for removing trace metals from contaminated water systems.  相似文献   
564.
Various studies have revealed high concentrations of contaminants such as organochlorines (OCs) and heavy metals in Mediterranean cetaceans. A geographical trend of contamination (PCBs and DDTs) has been found for striped dolphin (Stenella coeruleoalba). In this study we used a non-lethal approach (skin biopsy) to investigate bioaccumulation of OCs, including polychlorobiphenyls (PCBs), DDTs, polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), trace elements (Hg, Cd, Pb) and CYP1A activity (BPMO) in nine striped dolphins sampled in the Aeolian area (Sicily - Italy) in summer 2002. The arithmetic mean value of BPMO activity in this group was 43.46 AUF/g tissue/h. This value is approximately 3 times and 5 times lower, respectively, than the value found in the Ionian and in the Ligurian groups. Skin biopsies of striped dolphins emerged as a suitable material for assessing the toxicological status of the various Mediterranean groups.  相似文献   
565.
Intersexuality has been found in both males and females of the marine/estuarine amphipod, Echinogammarus marinus, at polluted and reference sites in East Scotland. Polluted sites had significantly more intersex specimens than reference sites, however the cause of intersexuality is unclear. Discriminant analysis of morphometric data showed that normal male specimens from the most polluted site resembled pooled intersex males, suggesting that subtle endocrine disruption (ED) maybe occurring in these otherwise apparently normal males. The main discriminating character was gnathopod size, recognised to be under androgenic gland control. The association of distinctive morphometry with intersexuality may provide a new approach to biomarkers of ED in crustaceans. The opportunities for other novel biomarkers, for example biochemical or behavioural markers, may also be explored through study of intersex animals.  相似文献   
566.
Three sediment transport studies using tracers were performed at Ancão Inlet (southern Portugal). The objectives of the experiments were to understand the sediment transport pathways and to determine their magnitudes on the updrift margin of an inlet. In order to apply the traditionally used Space Integration Methodology to the tracer experiments, adaptations were required. The study area was divided into four morphologically defined sectors and this was found to be a key factor for the applicability of tracers in a complex area. The four sectors are as follows: sector A is the straight part of the updrift beach; sector B is the upper area of the swash platform; sector C is the lower area of the swash platform; and sector D represents the inner parts of the inlet margin. The integrated analysis of all collected data (forcing mechanisms, tracer distribution and topographic evolution) led to the determination of the sediment pathways. A semi-quantitative conceptual model was developed in order to explain the sediment transport pathways and magnitudes that a known mass of sediment would follow after arriving at the swash platform. It was found that the areas with the largest sediment accumulation were sectors B and C, while almost no sediment was retained in sector D, which experienced significant erosion. According to the model, 53% of the initial mass of sediments remain in the system after two tidal cycles. It is hypothesised that sediment losses are caused by sediment transport towards the ebb delta and by sediment bypassing occurring from the ebb delta to the downdrift beach through swash bar processes. The herein defined conceptual model represents a useful tool that could be applied to other tidal inlets under similar conditions, facilitating sediment budget studies around tidal inlets.  相似文献   
567.
The Maastrichtian–Danian limestones of the Yacoraite Formation (northwestern Argentina) show carbon and oxygen isotopic values consistent with shallow marine conditions. The members of the formation respond to different sedimentary environments and are characterised by distinctive stable isotopes and geochemistry. The basal Amblayo Member is composed of high-energy dolomitic limestones and limestones with positive isotopic values (+2‰ δ13C, +2‰ δ18O). The top of the member reveals an isotopic shift of δ13C (−5‰) and δ18O (−10‰), probably related to a descent in the sea level. The sandy Güemes Member has isotopically negative (−2‰ δ13C, −1‰ δ18O) limestones, principally controlled by water mixing, decreased organic productivity, and compositional changes in the carbonates. The isotopically lighter limestones are calcitic, with a greater terrigenous contribution and different geochemical composition (high Si–Mn–Fe–Na, low Ca–Mg–Sr). These isotopic and lithological changes relate to the Cretaceous–Palaeogene transition. The Alemanía Member, composed of dolomitic limestones and pelites, represents a return to marine conditions and shows a gradual increase in isotopic values, reaching values similar to those of the Amblayo Member. The Juramento Member, composed of stromatolite limestones, shows isotopic variations that can be correlated with the two well-defined, shallowing-upward sequences of the member.  相似文献   
568.
The Zgorzelec-Wiżajny profile cuts through the main European geotectonic units of the Palaeozoic Western and Central European Platform and the East European Craton, including the connecting Trans-European Suture Zone. The paper summarises 40 years of research on geomagnetic secular variations along the Zgorzelec-Wiżajny profile since 1966. It discusses methods of processing measurement records and presenting their results. The latter are presented against the background of the local geology and the crustal deep magnetic structure data. The hitherto method of variation analysis was modified to address a new trend in the geomagnetic secular variations that has emerged in the East European Craton during the last five years (2001–2005).  相似文献   
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570.
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