Spectral investigation of the chromosphere     

U. Grossmann-Doerth  Marina Von Uexküll 《Solar physics》1977,55(2):321-333

Several hundred H spectrograms from areas close to the solar limb were taken with the 35 cm Coudé refractor at Anacapri. The 41 spectra with the greatest spatial resolution were selected and analysed. At the supergranular boundaries a considerable fraction of the line profiles were found to correspond to Beckers Cloud Model (BCM). Moreover, the BCM parameters of the dark mottles at the limb appear to be approximately equal to those from the center of the disk. On the other hand, we also obtained evidence in disagreement with the general applicability of the BCM to all features of the chromospheric fine structure.We attempted to present the large set of observational data in a fashion that permits their interpretation by alternative theoretical models.Mitteilungen aus dem Fraunhofer Institut Nr. 151.  相似文献   

Decision-support systems for groundwater protection: innovative tools for resource management   总被引：1，自引：0，他引：1  

Stefan Kollarits  Gerhard Kuschnig  Miran Veselic  Ante Pavicic  Corrado Soccorso  Marina Aurighi 《Environmental Geology》2006,49(6):840-848

Governmental authorities are forced by law to make decisions within the framework of European, national and regional directives in the fields of spatial planning, groundwater and environmental protection. These tasks can be supported by a decision-support system, which integrates data from various sources and helps to make decision processes more effective and transparent. Basic work for such a decision support system has been done in a transnational and interdisciplinary project (Interreg II C: KATER), including metadata definition, metadata system, cartographic tools and GIS tools. The direct integration of these tools and information in the decision process will be implemented in the next few years (project KATER II).  相似文献   

Potential of High-Resolution Satellite Data in the Context of Vulnerability of Buildings   总被引：1，自引：2，他引：1  

Marina Mueller  Karl Segl  Uta Heiden  Hermann Kaufmann 《Natural Hazards》2006,38(1-2):247-258

High-resolution space-borne remote sensing data are investigated for their potential to extract relevant parameters for a vulnerability analysis of buildings in European countries. For an evaluation of large earthquake scenarios, the number of parameters in models for vulnerability is reduced to a minimum of relevant information such as the type of building (age, material, number of storeys) and the geological and spatial context. Building-related parameters can be derived from remote sensing data either directly (e.g. height) or indirectly based on the recognition of the urban structure type in which the buildings are located. With the potential of a fully- or semi-automatic inventory of the buildings and their parameters, high-resolution satellite data and techniques for their processing are a useful supporting tool for the assessment of vulnerability.  相似文献   

Book reviews: Catalogue of Meteorites, 5th ed., revised and enlarged, by Monica M. Grady. Cambridge University Press, 2000, 689 pp., US $150.00 (ISBN 0521-66303-2)     

Marina A Ivanova 《Geochimica et cosmochimica acta》2002,66(3):541

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Length-specific carbon content of theDaphnia population in a large subalpine lake, Lago Maggiore (Northern Italy): The importance of seasonality     

Marina Manca  Patrizia Comoli  Teresa Spagnuolo 《Aquatic Sciences - Research Across Boundaries》1997,59(1):48-56

We compared three methods for calculating the standing stock biomass ofDaphnia hyalina galeata population in Lago Maggiore during a single year. We applied body length/carbon regression equations (LCR) obtained under controlled laboratory conditions and directly from field data on carbon and body length to field data on length-specific abundance. Laboratory-derived equations satisfactorily described our field estimates of length-specific carbon content in spring. As the length-standardized carbon content decreased exponentially along the season, we included time of the year as an auxiliary variable, and tested whether it affected slope, intercept or both. The decrease had no effect on slope but reduced the intercept of the LCR. We also calculated biomass, using a single mean value from the literature. By comparing the results with those obtained by simple conversion of individuals number into carbon we might discriminate between the effect of changes in the size frequency distribution of the population and the decrease with time of the length-standardized carbon content. Although we tested the different models for non-ovigerous females, the results did not change when we included also data on females with eggs in the first three developmental stages, whereas they changed substantially when we included females with embryos. We formulate two hypotheses to explain this result and discuss possible implications for the calculation of the standing stock biomass ofDaphnia population.  相似文献   

High‐temperature gold‐copper extraction with chloride flux in lava tubes of Tolbachik volcano (Kamchatka)     

Vadim S. Kamenetsky  Alexander Belousov  Victor V. Sharygin  Liudmila M. Zhitova  Kathy Ehrig  Michael E. Zelenski  Ilya Chaplygin  Marina A. Yudovskaya  Pavel N. Nesterenko  Sergey M. Zakharov 《地学学报》2019,31(6):511-517

Subvolcanic environments in supra‐subduction zones are renowned for hosting epithermal deposits that often contain electrum and native gold, including bonanza examples. This study examined mineral assemblages and processes occurring in shallow‐crust volcanic settings using recent eruption (2012–2013) of the basaltic Tolbachik volcano in the Kamchatka arc. The Tolbachik eruptive system is characterized by an extensive system of lava tubes. After cessation of magma input, the tubes maintained the flow of hot oxidized gases that episodically interacted with the lava surfaces and sulphate‐chloride precipitates from volcanic gases on these surfaces. The gas‐rock interaction had strong pyrometamorphic effects that resulted in the formation of molten salt, oxidized (tenorite, hematite, Cu‐rich magnesioferrite) and skarn‐like silicate mineral assemblages. By analogy with experimental studies, we propose that a combination of these processes was responsible for extraction of metals from the basaltic wall rocks and deposition of Cu‐, Fe‐ and Cu‐Fe‐oxides and native gold.  相似文献   

Response of suspended sediment particle size distributions to changes in water chemistry at an Andean mountain stream confluence receiving arsenic rich acid drainage          下载免费PDF全文

Maria Abarca  Paula Guerra  Guillermo Arce  Mauricio Montecinos  Cristian Escauriaza  Marina Coquery  Pablo Pastén 《水文研究》2017,31(2):296-307

Acid drainage is an important water quality issue in Andean watersheds, affecting the sustainability of urban, agricultural, and industrial activities. Mixing zones receiving acid drainage are critical sites where changes in pH and chemical environment promote the formation and dissolution of iron and aluminum oxy/hydroxides. These particles can significantly change the speciation of toxic metals and metalloids throughout drainage networks via sorption, desorption, and settling processes. However, little is known about the behavior of particle size distributions (PSDs) in streams affected by acid drainage and their relationship to metal speciation. This work studied: (a) the PSDs for a wide range of mixing ratios found at a fluvial confluence affected by acid drainage, and (b) the response of PSDs and arsenic speciation to environmental changes found when the particles approach complete mixing conditions. The confluence between the Azufre River (pH ~ 2, high concentration of dissolved metals) and Caracarani River (pH = 8.6, low concentration of dissolved metals) was used as a representative model for study. Field measurements show a bimodal PSD with modal diameters of ~50 and 300 μm. At shorter distances from the junction, the smaller modes with smaller particle volumes were dominant across the stream cross‐sections. A systematic shift towards larger particle sizes and larger particle volumes occurred downstream. The analysis of laboratory PSDs for Azufre/Caracarani mixing ratios between 0.01 and 0.5 (pH from 6.2 to 2.3) showed a bimodal trend with ~15 and 50 μm characteristic diameters; larger particles formed at pH>4. When particle suspensions were transferred in laboratory experiments from very low pH to full mixing conditions (pH ~ 2.8 and mixing ratio ~ 0.25) particle sizes varied, and the dissolved arsenic concentration decreased. The observed reaction kinetics were slow compared to the time scale of advective transport, creating opportunities for engineered controls for arsenic. This work contributes to a better understanding of the chemical‐hydrodynamic interactions in watersheds affected by mining, and identifying opportunities to improve water quality at points of use.  相似文献   

An example of karst catchment delineation for prioritizing the protection of an intact natural area     

Vesna Ristić Vakanjac  Zoran Stevanović  Aleksandra Maran Stevanović  Boris Vakanjac  Marina Čokorilo Ilić 《Environmental Earth Sciences》2015,74(12):7643-7653

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Ophiolites of the Eastern Peninsulas zone (Eastern Kamchatka): Age, composition, and geodynamic diversity     

Nikolay V.  Tsukanov  Wolfgang  Kramer  Sergey G.  Skolotnev  Marina V.  Luchitskaya  Wolfgang  Seifert 《Island Arc》2007,16(3):431-456

Abstract   The geological, geochemical and mineralogical data of dismembered ophiolites of various ages and genesis occurring in accretionary piles of the Eastern Peninsulas of Kamchatka enables us to discriminate three ophiolite complexes: (i) Aptian–Cenomanian complex: a fragment of ancient oceanic crust, composed of tholeiite basalts, pelagic sediments, and gabbroic rocks, presently occurring in a single tectonic slices (Afrika complex) and in olistoplaques in Pikezh complex of the Kamchatsky Mys Peninsula and probably in the mélange of the Kronotsky Peninsula; (ii) Upper Cretaceous complex, composed of highly depleted peridotite, gabbro and plagiogranite, associated with island arc tholeiite, boninite, and high-alumina tholeiitic basalt of supra-subduction origin; and (iii) Paleocene–Early Eocene complex of intra-island arc or back-arc origin, composed of gabbros, dolerites (sheeted dykes) and basalts produced from oceanic tholeiite melts, and back-arc basin-like dolerites. Formation of the various ophiolite complexes is related to the Kronotskaya intra-oceanic volcanic arc evolution. The first ophiolite complex is a fragment of ancient Aptian–Cenomanian oceanic crust on which the Kronotskaya arc originated. Ophiolites of the supra-subduction zone affinity were formed as a result of repeated partial melting of peridotites in the mantle wedge up to the subduction zone. This is accompanied by production of tholeiite basalts and boninites in the Kamchatsky Mys segment and plagioclase-bearing tholeiites in the Kronotsky segment of the Kronotskaya paleoarc. The ophiolite complex with intra-arc and mid-oceanic ridge basalt geochemical characteristics was formed in an extension regime during the last stage of Kronotskaya volcanic arc evolution.  相似文献   

Spectroscopic investigation of the chromosphere     

Ulrich Grossmann-Doerth  Marina Von Uexküll 《Solar physics》1973,30(1):71-74

The line profile of H as emanating from the interior of supergranular cells was measured at sin = 0, 0.6, 0.8 and 0.9. The measurements are described and the results presented.Mitteilung aus dem Fraunhofer Institut Nr. 117.  相似文献