Die Definitionen von Grauwacke,Arkose und Ton     

Wilhelm Salomon 《International Journal of Earth Sciences》1916,6(7-8):398-404

Ohne Zusammenfassung  相似文献   

Ein geologischer Querschnitt durch den Vogelsberg von Gießen bis Stockhausen bei Lauterbach     

Wilhelm Schottler 《International Journal of Earth Sciences》1931,22(3-4):161-168

Ohne Zusammenfassung  相似文献   

Die Bildung der Dreikanter     

San.-Rat Dr. Wilhelm Pfannkuch 《International Journal of Earth Sciences》1913,4(5-6):311-318

Ohne Zusammenfassung  相似文献   

Physiological changes in the coastal marine cyanobacterium Synechococcus sp. PCC 7002 exposed to low ferric ion levels     

Charles G. Trick  Steven W. Wilhelm 《Marine Chemistry》1995,50(1-4)

Cyanobacteria are ubiquitous in marine waters. These prokaryotic cells are of particular interest in areas of the ocean where the availability of iron may be limiting for cell growth since these organisms commonly excrete iron-specific organic ligands (siderophores) in response to low levels of iron. It is generally considered that the production of siderophores provides a competitive advantage over the competing microorganisms that do not produce these ligands.In order to ascertain the influence of iron availability on the physiology of picoplanktonic cyanobacteria we performed a series of experiments on the coastal coccoid cyanobacterium, Synechococcus sp. PCC 7002. Physiological responses were examined in cells grown in a continuous cuture system with influx media containing a range of iron concentrations (from 4.2 × 10⁻⁵ to 5.1 × 10⁻⁹ M FeCl₃). Steady-state growth rates, combined with growth data from batch cultures demonstrated a non-linear response between iron availability and cell proliferation: cell yields were considerably higher in the lowest-iron chemostats than predicted based on the yields in the higher-iron chemostats. The higher yields during low-iron growth corresponded with the production of the extracellular siderophores and the induction of the specific iron-siderophore membrane transport proteins. A comparison of iron transport and carbon acquisition rates between the low-iron grown cells and the high-iron grown cells indicates that under low-iron growth conditions, iron and carbon acquisition meets the growth demands of the cells, whereas growth at higher iron levels enabled excessive (luxury) carbon acquisition and storage. We conclude that cyanobacteria are efficiently adapted to grow in low-iron environments (providing sufficient light for photosynthesis is available) and the luxury-uptake of carbon may serve as the source material for the extracellular ligands released by these cells. Since the release of siderophores was at iron levels in excess of the levels that induce the siderophore-mediated transport of iron, cyanobacteria growing in an environment with varying levels of iron may contribute substantial amounts of their stored carbon reserves into the DOC as iron-specific ligands.  相似文献   

Decoding dispossession: Eviction and urban regeneration in Johannesburg's dark buildings          下载免费PDF全文

Matthew Wilhelm‐Solomon 《Singapore journal of tropical geography》2016,37(3):378-395

In January 2012 the residents of an inner‐city tenement building in Doornfontein, Johannesburg, were evicted on a court order. The building was situated in a post‐industrial neighbourhood in which thousands of South Africans and foreign nationals, many blind or disabled, live in unlawfully occupied buildings without access to water, basic sanitation, electricity and waste management services. Such buildings are known in policy discourse as ‘bad buildings’, and informally as ‘dark buildings’, invoking both a sense of developmental failure and spiritual insecurity. In this paper I analyse how urban renewal policies created social divisions and alliances not only among the residents of Chambers, which were channelled along nationalist lines, but also between the able‐bodied and disabled, and produced new social alliances. In particular, I document how a group of blind Zimbabweans experienced threats of violence and accusations of betrayal, as they were offered alternate accommodation by the evicting company because of their disability. I argue here that the pressures of private‐sector housing developments intersected with the insecurities and divisions of inner‐city social spaces and also fostered new alliances. Following the work of Deleuze and Guattari, I invoke the concept of ‘decoding dispossession’, proposing that ongoing evictions and dispossessions are characterized by simultaneous movements of ‘decoding and deterritorialization’ and ‘overcoding‐reterritorialization’.  相似文献   

Geothermal evolution of the Astrakhan Arch region of the Pricaspian basin     

Alik Ismail-Zadeh  Helmut Wilhelm  Yuri Volozh 《International Journal of Earth Sciences》2008,97(5):1029-1043

The Astrakhan Arch region contains one of the largest sub-salt structures of the Pricaspian basin, where perspectives for hydrocarbon generation and accumulation in the Devonian to Carboniferous deposits are considered to be high. The paper addresses the problem of structural and geothermal evolution of the region deformed by salt movements. Initially, we developed a model of the regional structural evolution along a geological profile using the volume-balancing and back-stripping methods and geological constraints on the sedimentation, erosion, and paleo-water depths. Then we developed geothermal models (along the study profile) associated with the regional structural evolution. The models were constrained by the temperatures measured in four deep boreholes along the profile. We show that the present temperatures and heat flux are influenced by the presence of salt diapirs. Since the Early Carboniferous and till Middle Permian times, the temperatures predicted by the models vary significantly due to the regional transgression and the presence of seawater. The temperature of Devonian–Carboniferous carbonates increases since the Late Permian (time of post-salt deposition) and attains its maximum values in the SW-part of the profile. If the model assumptions concerning the constant vertical and zero lateral heat fluxes are valid, we can conclude that hydrocarbons are most likely to be generated in the SW-part of the region for the post-Early Permian time.  相似文献   

New aspects of absorption-line formation in intervening turbulent clouds -- III. The inverse problem in the study of H+D profiles     

Sergei A. Levshakov  Wilhelm H. Kegel  Fumio Takahara 《Monthly notices of the Royal Astronomical Society》1999,302(4):707-713

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Morphology, dynamics and plasma parameters of plumes and inter-plume regions in solar coronal holes     

K. Wilhelm  L. Abbo  F. Auch��re  N. Barbey  L. Feng  A. H. Gabriel  S. Giordano  S. Imada  A. Llebaria  W. H. Matthaeus  G. Poletto  N.-E. Raouafi  S. T. Suess  L. Teriaca  Y.-M. Wang 《Astronomy and Astrophysics Review》2011,19(1):1-70

Coronal plumes, which extend from solar coronal holes (CH) into the high corona and??possibly??into the solar wind (SW), can now continuously be studied with modern telescopes and spectrometers on spacecraft, in addition to investigations from the ground, in particular, during total eclipses. Despite the large amount of data available on these prominent features and related phenomena, many questions remained unanswered as to their generation and relative contributions to the high-speed streams emanating from CHs. An understanding of the processes of plume formation and evolution requires a better knowledge of the physical conditions at the base of CHs, in plumes and in the surrounding inter-plume regions. More specifically, information is needed on the magnetic field configuration, the electron densities and temperatures, effective ion temperatures, non-thermal motions, plume cross sections relative to the size of a CH, the plasma bulk speeds, as well as any plume signatures in the SW. In spring 2007, the authors proposed a study on ??Structure and dynamics of coronal plumes and inter-plume regions in solar coronal holes?? to the International Space Science Institute (ISSI) in Bern to clarify some of these aspects by considering relevant observations and the extensive literature. This review summarizes the results and conclusions of the study. Stereoscopic observations allowed us to include three-dimensional reconstructions of plumes. Multi-instrument investigations carried out during several campaigns led to progress in some areas, such as plasma densities, temperatures, plume structure and the relation to other solar phenomena, but not all questions could be answered concerning the details of plume generation process(es) and interaction with the SW.  相似文献   

Flow-through PSICAM: a new approach for determining water constituents absorption continuously   总被引：1，自引：0，他引：1  

Jochen Wollschläger  Maik Grunwald  Rüdiger Röttgers  Wilhelm Petersen 《Ocean Dynamics》2013,63(7):761-775

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CLIMATOLOGY OF SURFACE CYCLONE TRAJECTORY AND INTENSITY FOR HEAVY-SNOW EVENTS AT THREE MIDWESTERN STATIONS     

Gregory D. Bierly  John A. Harrington Jr.  Dwight F. Wilhelm 《自然地理学》2013,34(6):522-537

In this paper, we assess interstorm cyclone variations in intensity and motion for heavy-snow events at three north-central U.S. stations: Minneapolis, Madison, and Indianapolis. Daily data for the period from 1966 to 1996 were used to select the 157 storm events. Heavy-snow cyclone track location (latitude and longitude) and intensity (central pressure) means and standard deviations are calculated for each station and related to snowfall magnitude. The most northwesterly of the three stations, Minneapolis, had the largest median heavy-snowfall total and also the largest standard deviation in heavy-snowfall amount. Statistical analysis of surface cyclone parameters reveals significant interstation differences in storm trajectory and intensity measures for all cyclones and cyclogenesis group subsets. Chi-square tests suggest that the distribution of storms by month and cyclogenesis type is significantly nonrandom for all stations. Summary findings indicate that Midwestern heavy-snow events are dominated by southern Great Plains cyclones and that storms from secondary cyclogenic regions contribute to significant differences at the three selected locations. [Key words: cyclones, snowfall, Midwest.]  相似文献