Using provenance to disambiguate locational references in social network posts     

Thomas Hervey  Werner Kuhn 《International journal of geographical information science》2019,33(8):1594-1611

  相似文献   

Experimental hydrothermal alteration of basaltic glass with relevance to Mars     

C. Stre  H. Hellevang  L. Riu  H. Dypvik  C. Pilorget  F. Poulet  S. C. Werner 《Meteoritics & planetary science》2019,54(2):357-378

Phyllosilicates, carbonates, zeolites, and sulfates on Mars give clues about the planet's past environmental conditions, but little is known about the specific conditions in which these minerals formed within the crust and at the surface. The aim of the present study was to gain increased understanding on the formation of secondary phases by hydrothermal alteration of basaltic glass. The reaction processes were studied under varying conditions (temperature, pCO₂, water:rock ratio, and fluid composition) with relevance to aqueous hydrothermal alteration in fully and partly saturated Martian basalt deposits. Analyses made on reaction products using X‐ray diffraction (XRD) and scanning electron microscope (SEM) were compared with near infrared spectroscopy (NIR) to establish relative detectability and spectral signatures. This study demonstrates that comparable alteration minerals (phyllosilicates, carbonates, zeolites) form from vapor condensing on mineral surfaces in unsaturated sediments and not only in fully water‐saturated sediments. In certain environments where water vapor might be present, it can alter the basaltic bedrock to a suite of authigenic phases similar to those observed on the Martian surface. For the detection of the secondary phases, XRD and SEM‐EDS were found to be superior to NIR for detecting and characterizing zeolites. The discrepancy in detectability of zeolites between NIR and XRD/SEM‐EDS might indicate that zeolites on Mars are more abundant than previously thought.  相似文献   

Temporal variability of three different macrofauna communities in the northern North Sea     

Ulrike Schückel  Siegfried Ehrich  Ingrid Kröncke 《Estuarine, Coastal and Shelf Science》2010

In 1999, 2003 and 2007 macrofauna communities were sampled in three different areas (“Boxes”) of 10 × 10 nautical miles in the northern North Sea in order to study the temporal changes in community structure in relation to changes in temperature or changes in hydrography.  相似文献   

An analysis of the hydrodynamic forces on cables and nets     

Werner Blendermann 《Applied Ocean Research》1987,9(4):224-233

In addition to tangential and transverse resistance, force deflection and maximum lift are characteristic for the hydrodynamic loading of cables and nets. Respective data are derived from model tests. Current cable loading functions are discussed, and a loading concept suitable for cables and nets is proposed.  相似文献   

DNA damage and apoptosis in the mussel Mytilus galloprovincialis   总被引：4，自引：0，他引：4  

Micić M  Bihari N  Jaksić Z  Müller WE  Batel R 《Marine environmental research》2002,53(3):243-262

The effects of known genotoxic substances (4-nitroquinoline-N-oxide, benzo[a]pyrene, teniposide, etoposide, cycloheximide, tributyltin) on human cells (FLC, HL-60) and on mussels were investigated. The correlations between formation of DNA strand breaks and DNA fragmentation characteristic for the process of apoptosis were estimated. Strand breaks induced by 4-nitroquinoline-N-oxide and benzo[a]pyrene did not correlate with DNA fragmentation detected in the process of apoptosis. Induction of internucleosomal DNA fragmentation in HL-60 cells was initiated by teniposide, etoposide and tributyltin, while in the gills of mussels this was detected only with tributyltin. Levels of DNA strand breaks in natural mussel populations, living at locations under the influence of urban and industrial wastes, do not mirror the apoptotic processes.  相似文献   

The Cretaceous of the Eastern Bangong-Nujiang Suture Zone (Tibet):Tectono-Sedimentation     

Pujun Wang  Frank Mattern  Werner Schneider  Wanzhu Liu  Shikai Li  Cai Li 《东北亚地学研究》2003,(1)

1IntroductionThe Tibet plateau consists of terranes which were accreted in a southward-younging succession from Late Permian to Mid-Eocene (Dewey etal., 1988; Mattern etal., 1998; Mattern and Schneider, 2000). The Songpan-Ganzi terrane was accreted to the Kunlun during Late Permian along Kunlun-Qin-ling suture. The Qiangtang block was added onto the Songpan-Ganzi terrane at the Jinsha suture dur-ing Late Triassic-Early Jurassic. The Lhasa block became attached to the Qia…  相似文献   

Alto Bkachner (Hrsg.): G. F. Brander 1713- 1783. Wissenschaftliche Instrumente aus seiner Werkstatt. Deutsches Mu-seum München. München 1983. 395 Seiten     

Werner Bronkalla 《Astronomische Nachrichten》1985,306(5):282-282

  相似文献