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11.
Socioeconomic segregation in European capital cities. Increasing separation between poor and rich 总被引：1，自引：1，他引：0
Socioeconomic inequality is on the rise in major European cities, as are concerns over it, since it is seen as a threat to social cohesion and stability. Surprisingly, relatively little is known about the spatial dimensions of rising socioeconomic inequality. This paper builds on a study of socioeconomic segregation in 12 European cities: Amsterdam, Athens, Budapest, London, Madrid, Oslo, Prague, Riga, Stockholm, Tallinn, Vienna, and Vilnius. Data used derive from national censuses and registers for 2001 and 2011. The main conclusion is that socioeconomic segregation has increased. This paper develops a rigorous multifactor approach to understand segregation and links it to four underlying, partially overlapping, structural factors: social inequalities, globalization and economic restructuring, welfare regimes, and housing systems. Taking into account contextual factors resulted in a better understanding of actual segregation levels, while introducing time lags between structural factors and segregation outcomes will likely further improve the theoretical model. 相似文献
12.
Several methods (Spectral Angle Mapper, first derivatives, spectral clustering) were used to test the possibility of discriminating live corals at the species level by using reflectance spectra obtained by close range underwater remote sensing. The Spectral Angle Mapper used with an in situ spectral library of 73 coral colonies recognised all corals correctly in an artificial remote sensing image created from the same coral spectra. The results did not change when “grey” noise was added to each pixel in the artificial image or when the artificial image was made from reflectance spectra modelled through a 5-m water column. The results showed that the within-species variability in optical properties of a set of four coral species, for which at least three different specimens were measured, was as high as between-species variability. Thus, it is highly unlikely that hard corals can be discriminated at a species level by means of remote sensing. Cluster analysis showed that it is difficult to recognise corals also at the genus level (Acropora vs. non-Acropora) based on their reflectance spectra. However, visual inspection of the coral spectra and clustering analysis suggest that it is possible to separate three main optical types of corals: green, blue, and brown corals. This may form the basis for an optical classification of corals that is more suited for remote sensing than traditional taxonomy. 相似文献
13.
Aleksandr Gorlach Tiit Hang Volli Kalm 《Boreas: An International Journal of Quaternary Research》2017,46(3):486-502
Reconstructing ice‐lake histories is of considerable importance for understanding deglacial meltwater budgets and the role of meltwater reservoirs for sea‐level rise in response to climate warming. We used the latest data on chronology and ice‐sheet extents combined with an isostatically adjusted digital elevation model to reconstruct the development of proglacial lakes in the area of the Karelian ice stream complex of the Late Weichselian Scandinavian Ice Sheet on the East European Plain. We derived the deglacial ice lake development in seven time‐slices from 19 to 13.8 ka, assuming the individual ice‐marginal positions to be isochronous throughout the studied domain. Modelling is based on mapping of critical drainage thresholds and filling the depressions that are potentially able to hold meltwater. Such an approach underestimates the real dimensions of the ice lakes, because the role of erosion at the thresholds is not considered. Our modelling approach is sensitive to the (local) ice‐margin location. Our results prove the southward drainage of meltwater during the glacier extent maxima and at the beginning of deglaciation whereas rerouting to the west had taken place already around 17.5 ka, which is some 1.5 ka earlier than hitherto supposed. The total ice‐lake volume in the study area was lowest (~300 km3) during the maximum glacier extent and highest (~2000 km3) during the highstand of the Privalday Lake at c. 14.6 ka. At 14.6–14.4 ka, the Privalday Lake drained to the early Baltic Ice Lake. The released ~1500 km3 of water approximately corresponds to 20% of the early Baltic Ice Lake water volume and therefore it is unlikely that it was accommodated there. Thus, we argue that the additional meltwater drained through the Öresund threshold area between the early Baltic Ice Lake and the sea, becoming a part of the Scandinavian Ice Sheet's contribution to the Meltwater Pulse 1A event. 相似文献
14.
To describe and analyse the role of sediments in the matter cycling in large shallow transboundary Lake Peipsi (L. Peipsi)
in north-eastern Europe, detailed surface-sediment mapping was conducted. On the basis of grain size the surface sediments
fall into three groups: coarse-grained sediments (prevailingly sands in the lake’s southern part), fine-grained sediments
(mainly silts) and silty sands, both in the central deeper part within the 8-m depth contour. The groups of deposits have
a distinct spatial distribution, determined mainly by the current system in the lake. The main source of bottom sediments
is the erosion of the lake floor and shores, the role of the river input seems to be limited. Fine-grained organic-rich sediments
are very cohesive, playing the main role in the circulation of various inorganic and organic pollutants like nutrients and
xenobiotics. Due to the cohesive character of the sediments their physical and chemical properties are extremely diverse and
if the near-bottom shear stress increases (extreme meteorological events, changes in the water level, etc.), the lake floor
may be subjected to episodic erosion and resuspension, which may cause remobilisation of impurities in muddy sediments and
their return to the food chain. 相似文献
15.
Alar Rosentau Ieva Grudzinska Edyta Kalińska Helena Alexanderson Valdis Bērziņš Aija Ceriņa Laimdota Kalniņa Jānis Karušs Kristaps Lamsters Merle Muru Māris Nartišs Līga Paparde Tiit Hang 《Boreas: An International Journal of Quaternary Research》2023,52(4):517-537
Holocene relative shore-level changes and development of the Ģipka palaeolagoon in the western Gulf of Riga are reconstructed using multiproxy analyses by combining litho-, biostratigraphical and chronological data with remote sensing and geophysical data. The results show the development of the Ģipka basin from the Ancylus Lake/Initial Litorina Sea coastal zone (before c. 9.1 cal. ka BP) to coastal fen (c. 9.1 to 8.4 cal. ka BP) and gradual development of the Litorina Sea lagoon (c. 8.4 to 4.8 cal. ka BP) and its transition to a freshwater coastal lake (c. 4.8 to 4.6 cal. ka BP), fen (c. 4.6 to 4.2 cal. ka BP), and river floodplain (since c. 4.2 cal. ka BP). The highest shorelines of the Ancylus Lake and Litorina Sea were mapped at an elevation of 12–11 and 9 m a.s.l., respectively. A new relative shore level (RSL) curve for the western Gulf of Riga was constructed based on RSL data from the Ģipka area and from nearby Ruhnu Island studied earlier. The reconstruction shows that the beginning of the last marine transgression in the western Gulf of Riga started at c. 8.4 cal. ka BP, and concurred with the 1.9 m RSL rise event recorded from the North Sea basin. Diatom analysis results indicate the existence of the Ģipka lagoon between c. 7.7 and 4.8 cal. ka BP, with the highest salinity c. 6.1 cal. ka BP. During the existence of the brackish lagoon, settlement sites of the Neolithic hunter–gatherer groups existed on the shores of the lagoon in the period c. 6.0 to 5.0 cal. ka BP. 相似文献
16.
Tiit Kutser Ele Vahtme Chris M. Roelfsema Liisa Metsamaa 《Estuarine, Coastal and Shelf Science》2007,75(4):559-563
The creation of seagrass biomass maps by diving/snorkelling is time-consuming and expensive. This paper presents a method for estimating seagrass dry weight using a photo-library of classes of differing seagrass biomass. Field data were collected at seagrass beds in Ngederrak Reef, Palau, in 2006. Photos of 25 × 25 cm quadrats were taken prior to the collection the above-ground biomass for determination of biomass dry weight. Fifteen classes of seagrass biomass and substrate type were identified. The dry weight for each class of seagrass was measured in laboratory. A photo-library was created for biomass classification where each in situ quadrat photo is accompanied with seagrass dry weight of the sample and a photo of the sorted sample taken in laboratory. The photo-library of quadrats was then used to estimate seagrass biomass on photos gathered along 100 m long transects at 2 m intervals. This procedure was conducted by three different observers. The seagrass dry weight estimates were consistent between interpreters even if one of the interpreters had no experience in seagrass research. This approach allows quick collection of seagrass dry weight data over large areas. The method can be used for creating seagrass biomass maps by snorkelling/diving and/or for calibrating and validating biomass maps created by remote sensing. 相似文献
17.
Tiit Tammaru 《The Professional geographer》2002,54(4):544-556
Analysts of urbanization in socialist countries have often taken firm positions on the nature of urbanization under this particular social context, defending either universalistic or specific standpoints. It has been a remarkable contribution to the understanding of urbanization under central planning through formulating some of the key arguments. The issues at stake have not been resolved, however, and more empirical work would be welcome. An explorative approach is therefore taken in the current article, with a view to finding additional empirical evidence for or against the diverse set of arguments previously made. It focuses on the sources of urban and rural population growth in Estonia during the Soviet period (1945–1991). The analysis helps us to better understand how different causes intermingled to produce the process of urban and rural population change, which had some common features that hold true in cross–country comparisons and some specific ones that Estonia offers to the mosaic of world urbanization. 相似文献