X‐rays from young stars: A summary of highlights from the XMM‐Newton Extended Survey of the Taurus Molecular Cloud (XEST)     

M. Güdel 《Astronomische Nachrichten》2008,329(2):218-221

The XMM‐Newton Extended Survey of the Taurus Molecular Cloud (XEST) is a survey of the nearest large star‐forming region, the Taurus Molecular Cloud (TMC), making use of all instruments on board the XMM‐Newton X‐ray observatory. The survey, presently still growing, has provided unprecedented spectroscopic results from nearly every observed T Tauri star, and from ≈50% of the studied brown dwarfs and protostars. The survey includes the first coherent statistical sample of high‐resolution spectra of T Tauri stars, and is accompanied by an U ‐band/ultraviolet imaging photometric survey of the TMC. XEST led to the discovery of new, systematic X‐ray features not possible before with smaller samples, in particular the X‐ray soft excess in classical T Tauri stars and the Two‐Absorber X‐ray (TAX) spectra of jet‐driving T Tauri stars. This paper summarizes highlights from XEST and reviews the key role of this large project. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Social networks and healthy cities: spreading good practices based on a spanish case study          下载免费PDF全文

Paz Benito del Pozo  Néstor Serrano  Pilar Marqués‐Sánchez 《Geographical review》2017,107(4):624-639

The city of Vitoria‐Gasteiz in Spain is considered a “healthy city” and has implemented sustainable actions to increase the mobility of its healthcare professionals. The objectives of this study are firstly to account for the use of bicycles at work as a strategy for a healthy city and secondly to propose a conceptual framework for analyzing this network and its capacity to spread their practices The paradigm proposed is that of social networks, within which sharing between contacts is explained by means of two models: the “threshold model” and “opinion leaders”.  相似文献   

Die morphologischen Wirkungen des Eiszeitklimas im gletscherfreien Gelbiet     

Julius Büdel 《International Journal of Earth Sciences》1944,34(7-8):482-519

Ohne Zusammenfassung  相似文献   

First results from SPIFFI. I: The Galactic Center     

M. Horrobin  F. Eisenhauer  M. Tecza  N. Thatte  R. Genzel  R. Abuter  C. Iserlohe  J. Schreiber  A. Schegerer  D. Lutz  T. Ott  R. Schdel 《Astronomische Nachrichten》2004,325(2):88-91

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Negative ions in the auroral mesosphere during a PCA event around sunset     

C. F. del Pozo  E. Turunen  T. Ulich 《Annales Geophysicae》1999,17(6):782-793

This is a study of the negative ion chemistry in the mesosphere above Tromsø using a number of EISCAT observations of high energy proton precipitation events during the last solar maximum, and in particular around sunset on 23 October, 1989. In these conditions it is possible to look at the relative importance of the various photodetachment and photodissociation processes controlling the concentration of negative ions. The data analysed are from several UHF GEN11 determinations of the ion-plasma ACF together with the pseudo zero-lag estimate of the ‘raw’ electron density, at heights between 55 km and 85 km, at less than 1 km resolution. The power profiles from the UHF are combined with the 55-ion Sodankylä model to obtain consistent estimates of the electron density, the negative ion concentrations, and the average ion mass with height. The neutral concentrations and ion temperature are given by the MSIS90 model. These parameters are then used to compare the calculated widths of the ion-line with the GEN11 determinations. The ion-line spectrum gives information on the effects of negative ions below 70 km where they are dominant; the spectral width is almost a direct measure of the relative abundance of negative ions.  相似文献   

On the significance of the climate-dataset time resolution in characterising wind-driven rain and simultaneous wind pressure. Part I: scalar approach     

Pérez-Bella  José M.  Domínguez-Hernández  Javier  Cano-Suñén  Enrique  del Coz-Díaz  Juan J.  Alonso-Martínez  Mar 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(6):1783-1797

Stochastic Environmental Research and Risk Assessment - The joint action of wind-driven rain and wind pressure is the main cause of water penetration in building facades, which causes various...  相似文献   

Characterization of Estuarine and Fluvial Dissolved Organic Matter by Thermochemolysis using Tetramethylammonium Hydroxide     

J. D. H. van Heemst  J. C. del Rio  P. G. Hatcher  J. W. de Leeuw 《洁净——土壤、空气、水》2000,28(2):69-76

Selected samples of dissolved organic matter (DOM) isolated by ultrafiltration (UDOM) have been analyzed by thermochemolysis in the presence of tetramethylammonium hydroxide (TMAH). This technique cleaves ester and ether bonds of bio‐ and geological macromolecules and releases monomer subunits and methylates them in situ as their methyl ethers and methyl esters. Compared with conventional pyrolysis, TMAH thermochemolysis avoids decarboxylation of preexisting carboxylic moieties and produces aromatic acids as their methyl esters. Various phenolic derivatives, which might originate from incorporated lignin‐derived structures, from the highly aliphatic and resistant biopolymer cutan and also from proteinaceous materials, were identified among the products produced from UDOM upon thermochemolysis. The presence of lignin derivatives in UDOM indicates input of organic matter derived from terrestrial sources. Various aromatic acids, perhaps representing the final steps in the oxidation of the side‐chain during microbial oxidation of lignin, were released upon TMAH thermochemolysis, suggesting they are structural constituents of the UDOM. Different ratios of lignin‐derived materials, commonly determined using the CuO oxidation method, such as the Δ value, indicative of the amount of lignin present, the acid/aldehyde ratio (Ad/Al)_G, indicative of the extent of oxidative degradation of the lignin component, and the syringyl/guaiacyl (S/G) and p‐hydroxyphenyl/guaiacyl (P/G) ratios, indicative of the contribution for the different types of lignin, were determined.  相似文献   

Tectonic setting of the recent damaging seismic series in the Southeastern Betic Cordillera,Spain     

Emilio Rodríguez-Escudero  José J. Martínez-Díaz  José A. Álvarez-Gómez  Juan M. Insua-Arévalo  Ramón Capote del Villar 《Bulletin of Earthquake Engineering》2014,12(5):1831-1854

In this work we analyze the tectonic setting of the recent damaging seismic series occurred in the Internal Zones of the eastern Betic Cordillera (SE Spain) and surrounding areas, the tectonic region where took place the 11th May 2011 Mw 5.2 Lorca earthquake. We revisit and make a synthesis of the seven largest and damaging seismic series occurred from 1984 to 2011. We analyze their seismotectonic setting, and their geological sources under the light of recent advances in the knowledge on active faults, neotectonics, seismotectonics and stress regime, with special attention focused on the Lorca Earthquake. These seismic series are characterized by two types of focal mechanisms, produced mainly by two sets of active faults, NNW–SSE to NNE–SSW small (no larger than 20–30 km) extensional faults with some strike slip component, and E–W to NE–SW large strike slip faults (more than 50 km long) with some compressional component (oblique slip faults). The normal fault earthquakes related to the smaller faults are dominant in the interior of large crustal tectonic blocks that are bounded by the large E–W to NE–SW strike-slip faults. The strike slip earthquakes are associated to the reactivation of segments or intersegment regions of the large E–W to NE–SW faults bounding those crustal tectonic blocks. Most of the seismic series studied in this work can be interpreted as part of the background seismicity that occurs within the crustal blocks that are strained under a transpressional regime driven by the major strike slip shear corridors bounding the blocks. The seismotectonic analysis and the phenomenology of the studied series indicate that it is usual the occurrence of damaging compound earthquakes of M  \(\sim \)  5.0 associated with triggering processes driven by coseismic stress transfer. These processes mainly occur in the seismic series generated by NNW–SSE to NNE–SSW faults. These mechanical interaction processes may induce a higher frequency of occurrence of this kind of earthquakes than considered in traditional probabilistic seismic hazard assessments and it should be taken into account in future seismic hazard assessments.  相似文献   

Discrimination of Soils and Assessment of Soil Fertility Using Information from an Ion Selective Electrodes Array and Artificial Neural Networks          下载免费PDF全文

Aitor Mimendia  Juan M. Gutiérrez  Josep M. Alcañiz  Manel del Valle 《洁净——土壤、空气、水》2014,42(12):1808-1815

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A Comparison of Different Indirect Techniques to Evaluate Volcanic Intact Rock Strength     

Rodrigo del Potro  Marcel Hürlimann 《Rock Mechanics and Rock Engineering》2009,42(6):931-938

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