Acoustic plane-wave scattering from a rough surface over a random fluid medium

Acoustic plane-wave scattering from a rough surface overlying a fluid half-space with a sound-speed distribution subject to a small random variation is considered. Under the assumption that the surface roughness and medium randomness are statistically independent, the scattered field may be derived by first solving for the mean field in the medium, and then incorporating with boundary-perturbation method to obtain the total mean field and the power spectral density of the scattered field. The employed algorithm is compatible to the analysis available in the existing literature so that the formulations are conveniently integrated. The results for the power spectral density have shown that the effects of medium inhomogeneities on the rough surface scattering are limited in a spectral regime where the scattered components have shallow grazing angles. The distribution of the power spectral density over the space is primarily governed by the power spectrum and correlation lengths of the rough surface.     

The European coastal zone: characterization and first assessment of ecosystem metabolism

The geomorphic, oceanographic, terrestrial and anthropogenic attributes of the European coastal zone are described and published data on ecosystem function (primary production and respiration) are reviewed. Four regions are considered: the Baltic Sea, Mediterranean Sea, Black Sea and the European Atlantic coast including the North Sea. The metabolic database (194 papers) suffers from a non-homogeneous geographical coverage with no usable data for the Black Sea which was therefore excluded from this part of our study. Pelagic gross primary production in European open shelves is, by far, the most documented parameter with an estimated mean of 41 mmol C m⁻² d⁻¹, the lowest value is reported in the Mediterranean Sea (21 mmol C m⁻² d⁻¹) and the highest one in the Atlantic/North Sea area (51 mmol C m⁻² d⁻¹). Microphytobenthic primary production, mostly measured in shallow areas, is extrapolated to the entire 0–200 m depth range. Its contribution to total primary production is low in all regions (mean: 1.5 mmol C m⁻² d⁻¹). Although macrophyte beds are very productive, a regional production estimate is not provided in this study because their geographical distribution along the European coastline remains unknown. Measurements of pelagic community respiration are clearly too sparse, especially below the euphotic zone, to yield an accurate picture of the fate of organic matter produced in the water column. With a mean value of 17 mmol C m⁻² d⁻¹, benthic community respiration consumes approximately 40% of the pelagic organic matter production. Estuaries generally exhibit high metabolic rates and a large range of variation in all parameters, except microphytobenthic primary production. Finally, the problem of eutrophication in Europe is discussed and the metabolic data obtained in the framework of the Land–Ocean Interactions in the Coastal Zone (LOICZ) project are compared with available direct measurements of net ecosystem production.     

秦山核电站邻近水域生态特点

本文综述了1989年4月至1990年1月秦山核电站邻近水域生态调查结果,认为,该水域具暖温带强潮河口区生态特征。水体虽含丰富营养盐和充足溶解氧,由于同时存在着各种不利于生物繁殖生长的环境因子,表现为生物资源贫瘠、种类组成简单,测区所代表的强潮河口湾顶区属低生产力水域。     

Normative quartz as an indicator of the mass transfer intensity during the postmagmatic alteration of the Botuobinskaya pipe kimberlites (Yakutia)

The intensity of postmagmatic processes in the Botuobinskaya pipe kimberlites was estimated from the calculated content of normative secondary quartz (Q). Several simple algorithms are proposed to calculate the Q content from chemical analyses of kimberlites. Ten groups of altered kimberlites have been recognized from the Q contents. The contents of MgO, some trace elements, and LREE in the groups, the contents of Cr and Ca of crimson garnets, the diamond contents of kimberlites, and the average weight of diamonds decrease as the Q content increases. It is shown that the negative SiO₂–MgO correlation is the most effective indicator of the postmagmatic alteration of kimberlites. As the degree of their secondary alteration increases, the kimberlites transform into an assemblage of quartz and clay minerals enriched in some trace elements and almost completely lacking REE and diamonds.     

Tripartite climate reversal in Central Europe 5600-5300 years ago

The history of variations in water level of Lake Constance, as reconstructed from sediment and pollen analysis of a sediment sequence from the archaeological site of Arbon-Bleiche 3, shows an abrupt rise in lake level dendrochronologically dated to 5375 yr ago (5320 yr relative to AD 1950). This event, paralleled by the destruction of the Neolithic village by fire, provoked the abandonment of this prehistoric lake-shore location established in the former shallow bay of Arbon-Bleiche, and was the last of a series of three episodes of successively higher lake level, the first occurring at 5600-5500 cal yr B.P. The dendrochronologically dated rise event was synchronous with an abrupt increase in atmospheric ¹⁴C. This supports the hypothesis of an abrupt climate change forced by varying solar activity. Moreover, the three successive episodes of higher lake level between 5600 and 5300 cal yr B.P. at Arbon-Bleiche 3 coincided with climatic cooling and/or changes in moisture conditions in various regions of both hemispheres. This period corresponds to the mid-Holocene climate transition (onset of the Neoglaciation) and suggests inter-hemispheric linkages for the climate variations recorded at Arbon-Bleiche 3. This mid-Holocene climate reversal may have resulted from complex interactions between changes in orbital forcing, ocean circulation and solar activity. Finally, despite different seasonal hydrological regimes, the similarities between lake-level records from Lake Constance and from Jurassian lakes over the mid-Holocene period point to time scale as a crucial factor in considering the possible impact of climate change on environments.     

The political geography of religion: historical state-church relations in Europe and recent challenges

Historical processes of state formation and nation building are crucial for an understanding of the geography of religions and churches in Europe. Each country has developed its own model of state-church relations, giving rise to a ‘bewildering variety’ as Grace Davie aptly remarks. The aim of this paper is to bring some order to this variety by developing a framework for the comparative study of church-state relations based on Stein Rokkan’s famous conceptual map and recent extensions of it to Central and Eastern Europe by John Madeley. According to that framework Europe has been divided into three mono-confessional (Roman Catholic, Lutheran, and Eastern Orthodox) blocs and two multi-confessional culture belts from Northwest to Southeast, and from Northeast to Southeast. This historical pattern has been challenged by secularisation, which started with the Enlightenment and the French Revolution (Western Europe) and the Russian Revolution (Eastern Europe until the velvet revolutions of 1989/1991) and then became widespread after the ‘cultural revolutions’ of the 1960s. A second challenge has to do with globalisation and its consequences, such as massive immigration and the rise of immigrant religions, and in general deterritorialisation, which means the disembeddedness of religion from its national territory. A third challenge concerns reterritorialisation at other (supranational, regional, transnational, and local) scales, of which the new territorial order of the European Union seems to be the most important. Finally, this paper serves as an introduction to the case studies on church-state relations in this special issue.     

地震作用下的灰坝液化特征及其动力稳定性分析--以安阳电厂为例

根据安阳电厂灰坝岩土工程性质及其动力学特性,建立了适合灰坝工程的动力分析模型并采用有限元法进行了动力分析.在此基础上,在不同工况条件下对灰坝进行了抗液化安全评价及抗震稳定性分析.研究表明,在不设碎石桩、无排渗体条件下,粉煤灰子坝的抗液化安全系数Ks＜1.25,将发生液化;在设碎石桩、有排渗体条件下,粉煤灰子坝的抗液化安全系数明显提高,Ks≥1.25,不会发生液化.抗震稳定性分析表明,在上述两种工况条件下灰坝是稳定的.     

Analyzing CO2 emissions mitigation by technology improvement in Central and Eastern Europe

As a legacy of the centrally planned economy, the economies in transition of Central and Eastern Europe (CEE) have a unique potential to reduce their greenhouse gas emissions through the improvement in their high energy intensities. Since much of this `low-hanging fruit' in energy-efficiency improvements can be highly cost-effective, many developed countries facing difficulties in meeting their greenhouse gas (GHG) emission targets domestically are eager to find such opportunities in the CEE region. Therefore, studies analysing the potentials and costs of carbon dioxide reduction through technology improvement in the region have come into the limelight. While there are a few excellent studies in the region aimed at analysing climate change abatement potentials, they all embark on different assumptions, methodologies and boundary conditions. It is hence difficult, if not impossible, to compare and analyse the results of these studies across different authors, countries or time horizons. Consequently, the purpose of this paper is to place four leading studies on GHG mitigation through technology improvement from the CEE region into an internationally comparable framework. Four studies were selected from three countries, Poland, Hungary and Estonia, which are all the results of major national and international efforts to assess costs and potentials of GHG reduction. The paper places their assumptions, methods and final results into a framework which enables policy-makers and project designers to compare these across geographical and technological boundaries. Since other studies from around the globe have been analysed in this framework in the literature, this paper provides a vehicle for the findings of these four studies to be compared to others worldwide. In addition, the paper highlights a few areas where similar studies to be completed in the future in the region may be enhanced by incorporating features used in GHG mitigation research in other parts of the world. This revised version was published online in July 2006 with corrections to the Cover Date.     

Lithosphere structure of European sedimentary basins from regional three-dimensional gravity modelling

A three-dimensional (3D) density model, approximated by two regional layers—the sedimentary cover and the crystalline crust (offshore, a sea-water layer was added), has been constructed in 1° averaging for the whole European continent. The crustal model is based on simplified velocity model represented by structure maps for main seismic horizons—the “seismic” basement and the Moho boundary. Laterally varying average density is assumed inside the model layers. Residual gravity anomalies, obtained by subtraction of the crustal gravity effect from the observed field, characterize the density heterogeneities in the upper mantle. Mantle anomalies are shown to correlate with the upper mantle velocity inhomogeneities revealed from seismic tomography data and geothermal data. Considering the type of mantle anomaly, specific features of the evolution and type of isostatic compensation, the sedimentary basins in Europe may be related into some groups: deep sedimentary basins located in the East European Platform and its northern and eastern margins (Peri-Caspian, Dnieper–Donets, Barents Sea Basins, Fore–Ural Trough) with no significant mantle anomalies; basins located on the activated thin crust of Variscan Western Europe and Mediterranean area with negative mantle anomalies of −150 to −200×10⁻⁵ ms⁻² amplitude and the basins associated with suture zones at the western and southern margins of the East European Platform (Polish Trough, South Caspian Basin) characterized by positive mantle anomalies of 50–150×10⁻⁵ ms⁻² magnitude. An analysis of the main features of the lithosphere structure of the basins in Europe and type of the compensation has been carried out.