Social change and segregation in Copenhagen

This article examines socio-spatial changes resulting from economic and social restructuring in Copenhagen in recent decades. The main features of these changes have involved a sharp decline in manufacturing employment, a rise in the participation of women in the labour market, increasing unemployment among unskilled workers, a growing number of immigrants in obsolete dwellings and social housing estates, a relative decline in the number of families, and a growth in the numbers of single parent households. Do these changes challenge the classic models of segregation, or can they still be considered valid? Empirical evidence is produced concerning the socio-spatial effect of these changes in Copenhagen. The conclusion is that the classical model of social segregation is still valid, although some additional dimensions must be included. Furthermore, the overall socio-spatial structure of Copenhagen remains relatively intact, largely because of the inertia of the urban landscape and its social relations. However, the radical nature of the restructuring processes can also be called into question.     

Atmosphere and Earth's rotation

The theoretical aspects of the transfer of angular momentum between atmosphere and Earth are treated with particular emphasis on analytical solutions. This is made possible by the consequent usage of spherical harmonics of low degree and by the development of large-scale atmospheric dynamics in terms of orthogonal wave modes as solutions of Laplace's tidal equations.An outline of the theory of atmospheric ultralong planetary waves is given leading to analytical expressions for the meridional and height structure of such waves. The properties of the atmospheric boundary layer, where the exchange of atmospheric angular momentum with the solid Earth takes place, are briefly reviewed. The characteristic coupling time is the Ekman spin-down time of about one week.The axial component of the atmospheric angular momentum (AAM), consisting of a pressure loading component and a zonal wind component, can be described by only two spherical functions of latitude : the zonal harmonicP ₂ ⁰ (), responsible for pressure loading, and the spherical functionP ₁ ¹ () simulating supperrotation of the zonal wind. All other wind and pressure components merely redistributeAAM internally such that their contributions toAAM disappear if averaged over the globe. It is shown that both spherical harmonics belong to the meridional structure functions of the gravest symmetric Rossby-Haurwitz wave (0, –1)^*. This wave describes retrograde rotation of the atmosphere within the tropics (the tropical easterlies), while the gravest symmetric external wave mode (0, –2) is responsible for the westerlies at midlatitudes. Applying appropriate lower boundary conditions and assuming that secular angular momentum exchange between solid Earth and atmosphere disappears, the sum of both waves leads to an analytical solution of the zonal mean flow which roughly simulates the observed zonal wind structure as a function of latitude and height. This formalism is used as a basis for a quantitative discussion of the seasonal variations of theAAM within the troposphere and middle atmosphere.Atmospheric excitation of polar motion is due to pressure loading configurations, which contain the antisymmetric functionP ₂ ¹ () exp(i) of zonal wavenumberm=1, while the winds must have a superrotation component in a coordinate system with the polar axis within the equator. The Rossby-Haurwitz wave (1, –3)^* can simulate well the atmospheric excitation of the observed polar motion of all periods from the Chandler wobble down to normal modes with periods of about 10 days. Its superrotation component disappears so that only pressure loading contributes to polar motion.The solar gravitational semidiurnal tidal force acting on the thermally driven atmospheric solar semidiurnal tidal wave can accelerate the rotation rat of the Earth by about 0.2 ms per century. It is speculated that the viscous-like friction of the geomagnetic field at the boundary between magnetosphere and solar wind may be responsible for the westward drift of the dipole component of the internal geomagnetic field. Electromagnetic or mechanical coupling between outer core and mantle may then contribute to a decrease of the Earth's rotation rate.     

State formation and nation-building in the Netherlands and the Soviet Union: a historical comparison

The interrelated processes of state formation and nation-building are analysed for two cases: the Netherlands (1795–1960) and the Soviet Union (1917–1989). The central question is: how did these states deal with strong cultural (religious or ethnic) cleavages in its societies. In general, there are three options: elimination marginalization, and institutionalization. In both states institutionalization was dominant, but the kind of institutionalization differed very much: personalistic (the Netherlands) versus territorial (Soviet Union) institutionalization. The hypothesis has been put forward that, in general, institutionalization on a personalistic basis will create more political stability.     

On the possibility of nuclear processes in atmospheres of flare stars

A resume of the main results obtained in the framework of fast electron hypothesis is presented. The fast electrons are possessed by strong constant properties, that is, nearly monoenergetic in spectrum and with the energy of 3. Fast electrons appear spontaneously in all kinds of cool dwarfs, young and old, and stimulate the generation of all types of flares, faint and powerful, in all ranges of electromagnetic waves — optical, ultraviolet, radio, X-ray. The general flare mechanisms are inverse Compton effect at the faint and moderate flares and nonthermal bremsstrahlung at powerfulness. This hypothesis explains an enormous number of observational facts and relationships — all these are illustrated by two tree-like diagrams in Figures 1 and 2.In the second part, the problem of the spontaneous appearance of fast electrons above the stellar atmosphere is discussed. The nature of the fast electrons in universal and is independent of the physical conditions of the star or its atmosphere. Their origin have nothing in common also with the well known acceleration processes, including the magnetic and hydrodynamic nature, in stellar atmospheres. At present nuclear decay processes seem to be most probable for the appearance of fast electrons in outer regions of stellar atmospheres. Some decay processes are examined with various probability of their realization. Creation of the radioactive nucleus¹³N as a result of capture of H by¹²C and its consequent decay with the escape of a positron seems most probable; as this fast positron will act just like a fast electron. It is outlined the high effectivity of this process in binary systems.     

Similar reproductive cycles and life-history traits in congeneric limid bivalves with different modes of nutrition

We have studied two congeneric limid bivalves, Acesta species novum and Acesta excavata (Bivalvia: Limidae), that live in similar physical conditions but use different food sources. Acesta sp. nov. live on the giant siboglinid tubeworm Lamellibrachia luymesi at cold seeps and feed on their eggs, a continuous food source that ultimately is derived from chemosynthesis, whereas A. excavata relies on planktonic food of photosynthetic origin, which varies seasonally. We hypothesized that these two species might show differences in the periodicity of reproduction; specifically, we predicted that A. sp. nov. would breed continuously and that A. excavata would demonstrate an annual reproductive cycle. Our hypothesis was refuted, as both species have a semi‐continuous reproductive cycle. Food quality, quantity or seasonality had no clear effect. Reproductive adults are functionally gonochoristic. Females broadcast buoyant eggs with an average size of 179 μm in A. sp. nov. and 160 μm in A. excavata. Both the size of the larval shell and the size of the spawned eggs are suggestive of pelagic lecithotrophic development. Both species also appear to be protandric hermaphrodites, changing from male to female at approximately 77 and 90 mm shell height, respectively, although not all individuals change sex. In the material investigated in this study there was a biased sex ratio favouring males.     

Eelgrass (Zostera marina L.) as an indicator organism of trace metals in the Limfjord,Denmark

The concentrations of Pb, Cu, Cd and Zn were determined in above- and belowground parts of eelgrass (Zostera marina L.) at forty stations in a shallow, brackish water area (the Limfjord, Denmark). The concentrations of the trace metals were significantly elevated near the cities of Aalborg (Pb, Cu) and Struer (Cd). Trace metal concentrations in above and belowground parts of eelgrass were log-normal distributed and the concentrations of Cd, Cu and Zn in aboveground parts were significantly higher than in belowground parts. Furthermore, a significant correlation between trace metal concentrations in above- and belowground parts was found. The background level of trace metal concentrations in eelgrass in the Limfjord was estimated.The application of eelgrass as a monitoring organism is discussed; it is suggested that the concentration of some trace metals in above- and belowground parts of eelgrass may be used as a measure of the bioavailable fraction of these trace metals in ambient and interstitial water (sediment), respectively.     

Sedimentary,tectonic, and sea-level controls on submarine fan and slope-apron turbidite systems

To help understand factors that influence submarine fan deposition, we outline some of the principal sedimentary, tectonic, and sea-level controls involved in deep-water sedimentation, give some data on the rates at which they operate, and evaluate their probable effects. Three depositional end-member systems, two submarine fan types (elongate and radial), and a third nonfan, slope-apron system result primarily from variations in sediment type and supply. Tectonic setting and local and global sea-level changes further modify the nature of fan growth, the distribution of facies, and the resulting vertical stratigraphic sequences.