Kinematics of gas and stars in the circumnuclear star-forming ring of NGC 3351     

Guillermo F. Hägele †  Ángeles I. Díaz ‡  Mónica V. Cardaci †  Elena Terlevich §  Roberto Terlevich § 《Monthly notices of the Royal Astronomical Society》2007,378(1):163-178

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Palaeomagnetism of the Ferrar dolerite in the northern Prince Albert Mountains (Victoria Land, Antarctica)     

Roberto Lanza  Elena Zanella 《Geophysical Journal International》1993,114(3):501-511

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Complex geographical analysis of the Greater Sochi region on the Black Sea coast     

Elena A. Rybak  Oleg O. Rybak  Yuri V. Zasedatelev 《GeoJournal》1994,34(4):507-513

Results of the complex analysis of the unique natural territory of Greater Sochi from the point of view of physical geography are considered. The region of Greater Sochi is located on the S slopes of the Main Caucasus chain on the eastern coast of the Black Sea. Morphometrical analysis of the relief and analysis air surface temperature and precipitation allowed to distinguish four specific subregions within the whole territory. It is demonstrated that the period of stable snow cover in the two subregions which occupy more than half of the region's area is sufficient for successful development of winter tourism. Peculiar combination of the mild climate of the coast with stable snow cover in the mountains till the beginning of summer provide strong attractivity of the region for all-the-year-round tourists inflow to the most modern recreational centre of Russia. The work provides the methodology for similar studies.  相似文献   

Earthquake Swarms In the Kamchatka-Commander Region     

Vyacheslav M. Zobin  Elena I. Ivanova 《Geophysical Journal International》1994,117(1):33-47

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Chromite composition and platinum-group mineral assemblage in the Uktus Uralian-Alaskan-type complex (Central Urals,Russia)     

Giorgio?GarutiEmail author  Evgeny?V.?Pushkarev  Federica?Zaccarini  Roberto?Cabella  Elena?Anikina 《Mineralium Deposita》2003,38(3):312-326

Chromitite segregations in dunites of the Uktus Uralian-Alaskan-type complex (Central Urals, Russia) display large variation of the chromite composition: Cr/(Cr+Al)=0.46-0.77, Fe²⁺/(Fe²⁺+Mg)=0.28-0.66, and Fe³⁺/(Fe³⁺+Fe²⁺)=0.23-0.59. Three types of PGM assemblages have been recognized, varying in accordance with chromite composition: type I, dominated by Ru-Os-Ir (sulfides), is associated with magnesiochromite having Fe³⁺/(Fe³⁺+Fe²⁺)<0.30, in the southern dunite body. Type II, containing abundant Pt-Ir (alloys, minor sulfides), is found in magnesiochromite with Fe³⁺/(Fe³⁺+Fe²⁺)=0.40-0.44; type III, consisting of Ir-Rh-Pt-Pd (alloys, sulfarsenides, antimonides) in Fe-rich chromite having Fe²⁺/(Fe²⁺+Mg)=0.66 and Fe³⁺/(Fe³⁺+Fe²⁺)=0.59. Positive anomalies of Ir and Pt, and a negative peak of Ru characterize the PGE patterns of chromitites with type II and III PGM assemblages, whereas a positive Pt anomaly is observed in their dunite host. Intensive fractionation of Pt-Fe alloys in the Uktus chromitites reflects the anomalous behavior of Pt which is decoupled from Rh and Pd. Among other factors, the high iron activity and oxygen fugacity in the parent melt appear to exert a major control on precipitation of Pt-Fe alloys, below sulfur saturation. The strong Pt anomaly in chromitites from Uktus may indicate that Uralian-Alaskan-type magmas were derived from a Pt-rich mantle source.  相似文献   

Cytochrome P4501A expression,chemical contaminants and histopathology in roach,goby and sturgeon and chemical contaminants in sediments from the Caspian Sea,Lake Balkhash and the Ily River Delta,Kazakhstan   总被引：1，自引：0，他引：1  

Moore MJ  Mitrofanov IV  Valentini SS  Volkov VV  Kurbskiy AV  Zhimbey EN  Eglinton LB  Stegeman JJ 《Marine pollution bulletin》2003,46(1):107-119

Roach, goby and sturgeon were examined for cytochrome P4501A (CYP1A) expression and histopathology, in relation to contaminant burdens in fish and sediment. Gradients of induction of CYP1A were observed. Roach from the Ural and Ily River Deltas and roach and goby from the two stations nearest the Caspian Sea oil fields displayed higher levels of CYP1A expression in several organs than was observed in fish from further offshore. Great sturgeon and Russian sturgeon showed higher levels of CYP1A expression than was seen in starred sturgeon and gobies in the Ural delta. No fish showed evidence of contaminant-related histopathologies in the organs examined, despite the elevated CYP1A levels. Low levels of polychlorinated biphenyls and elevated levels of inshore and riverine petroleum hydrocarbons from these habitats suggest that this ongoing hydrocarbon exposure, and that from natural sources and long-term oil exploration on the Northeastern Caspian shore, contributed to the CYP1A induction observed.  相似文献   

The use of a non-lethal tool for evaluating toxicological hazard of organochlorine contaminants in Mediterranean cetaceans: new data 10 years after the first paper published in MPB     

Fossi MC  Marsili L  Neri G  Natoli A  Politi E  Panigada S 《Marine pollution bulletin》2003,46(8):972-982

In the Mediterranean Sea, top predators, and particularly cetacean odontocetes, accumulate high concentrations of organochlorine contaminants and toxic metals, incurring high toxicological risk. In this paper we investigate the use of the skin biopsies as a non-lethal tool for evaluating toxicological hazard of organochlorines in Mediterranean cetaceans, presenting new data 10 years after the paper published by Fossi and co-workers [Mar. Poll. Bull. 24 (9) (1992) 459] in which this new methodology was first presented. Some organochlorine compounds, now with worldwide distribution, are known as endocrine disrupting chemicals (EDCs). Here the unexplored hypothesis that Mediterranean cetaceans are potentially at risk due to organochlorines with endocrine disrupting capacity is investigated. High concentrations of DDT metabolites and PCB congeners (known as EDCs) were found in the different Mediterranean species (Stenella coeruleoalba, Delphinus delphis, Tursiops truncatus and Balaenoptera physalus). In this paper we also propose benzo(a)pyrene monooxygenase (BPMO) activity in marine mammal skin biopsies (non-lethal biomarker) as a potential indicator of exposure to organochlorines, with special reference to the compounds with endocrine disrupting capacity. A statistically significant correlation was found between BPMO activity and organochlorine levels (DDTs, pp(')DDT, op(')DDT, PCBs and PCB99) in skin biopsies of males of B. physalus. Moreover a statistical correlation was also found between BPMO activity and DDT levels in skin biopsies of the endangered Mediterranean population of D. delphis. These results suggest that BPMO induction may be an early sign of exposure to organochlorine EDCs and can be used for periodic monitoring of Mediterranean marine mammal toxicological status.  相似文献   

The late Quaternary evolution of the Negro River, Amazon, Brazil: Implications for island and floodplain formation in large anabranching tropical systems     

Edgardo M. Latrubesse  Elena Franzinelli 《Geomorphology》2005,70(3-4):372

The Rio Negro has responded significantly in the Late Pleistocene and Holocene to lagged environmental changes largely associated with activity during the last glacial in the Amazon basin. On the basis of geological structure, the Rio Negro can be divided into six distinct reaches that each reflects very marked differential processes and geomorphological styles. No deposits of the Upper Pleniglacial were recognized in the field. The oldest recognizable Late Pleistocene alluvial unit is the Upper Terrace of Middle Pleniglacial age (ca. 65–25 ka) (reach I), tentatively correlated with the oldest terrace identified on the left bank of reach III. At that time, the river was mainly an aggradational bed load system carrying abundant quartz sand, a product of more seasonal conditions in the upper catchment. The late glacial (14–10 ka) is represented by a lower finer-grained terrace along the upper basin (reach I), which was recognized in the Tiquié, Curicuriarí, and Vaupes rivers. At that time, the river carried abundant suspended load as a response to climatic changes associated with deglaciation.Since about 14 ka, the river has behaved as a progradational system, infilling in downstream series a sequence of structurally controlled sedimentary basins or ‘compartments,’ creating alluvial floodplains and associated anabranching channel systems. Reach II was the first to be filled, then reach III, both accumulating mainly sand. Fine deposits increase downstream in reach III and become predominant in some anabranch islands of the distal reach. The lowermost reaches of the Negro (V and VI) have been greatly affected by a rising base level and associated backwater effect from aggradation of the Amazon during late glacial and recent times. Reach V has acted almost entirely as a fine sediment trap. The remarkable Anavilhanas archipelago is the product of Holocene deposition in the upper part of this sedimentary basin; however, suspended sediment load declined about 1.5 ka, prior to the lower part of this basin becoming infilled.The progradational behavior of the Rio Negro, filling tectonic basins as successive sediment traps with sand in the upper basins and fines in the downstream ones, illustrates how a large river system responses to profound changes in Late Quaternary base level and sediment supply. The most stable equilibrium conditions have been achieved in the Holocene in reaches IIb and IIIa, where an anabranching channel and erosional–relictual island system relatively efficiently convey water and sediment downstream. Reaches IIIb and V never achieved equilibrium conditions during the Holocene, characterised as they are today with incomplete floodplains and open water.  相似文献   

Climate variability, predictability and climate risks: a european perspective     

Heinz Wanner  Martin Grosjean  Regine Röthlisberger  Elena Xoplaki 《Climatic change》2006,79(1-2):1-7

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The North-South Asymmetry in the Green Corona     

Elena Dzifčáková  Vojtech Rušin 《Studia Geophysica et Geodaetica》1998,42(2):101-111

The north-south asymmetry of the Fe XIV 530.3 nm coronal emission line (the green corona) over cycle 22 was investigated. The green corona line brightness was dominant in the southern hemisphere during cycle 22 (A = –0.07), except for short periods of the ascending phase of the activity cycle. The asymmetry of the semi-annual mean over the period 1940 – 1996 was also studied. The asymmetry, during these years, reached its maximum in 1962 – 1966, and then decreased. Important periodicities of the asymmetry in cycle 22, e.g., 158 and 350 days, 2.39 years were found. Similar periodicities were also detected in the years 1940 – 1996. An FFT analysis was used to detect these periodicities.  相似文献