Recovering the intrinsic shape of early-type galaxies     

Remco C. E. van den Bosch  Glenn van de Ven † 《Monthly notices of the Royal Astronomical Society》2009,398(3):1117-1128

We investigate how well the intrinsic shape of early-type galaxies can be recovered when both photometric and two-dimensional stellar kinematic observations are available. We simulate these observations with galaxy models that are representative of observed oblate fast-rotator to triaxial slow-rotator early-type galaxies. By fitting realistic triaxial dynamical models to these simulated observations, we recover the intrinsic shape (and mass-to-light ratio), without making additional (ad hoc) assumptions on the orientation.
For (near) axisymmetric galaxies, the dynamical modelling can strongly exclude triaxiality, but the regular kinematics do not further tighten the constraint on the intrinsic flattening significantly, so that the inclination is nearly unconstrained above the photometric lower limit even with two-dimensional stellar kinematics. Triaxial galaxies can have additional complexity in both the observed photometry and kinematics, such as twists and (central) kinematically decoupled components, which allows the intrinsic shape to be accurately recovered. For galaxies that are very round or show no significant rotation, recovery of the shape is degenerate, unless additional constraints such as from a thin disc are available.  相似文献   

Directional Wavelets and a Wavelet Variogram for Two-Dimensional Data     

E. H. Bosch  A. P. González  J. G. Vivas  G. R. Easley 《Mathematical Geosciences》2009,41(6):611-641

This paper describes two new approaches that can be used to compute the two-dimensional experimental wavelet variogram. They are based on an extension from earlier work in one dimension. The methods are powerful 2D generalizations of the 1D variogram that use one- and two-dimensional filters to remove different types of trend present in the data and to provide information on the underlying variation simultaneously. In particular, the two-dimensional filtering method is effective in removing polynomial trend with filters having a simple structure. These methods are tested with simulated fields and microrelief data, and generate results similar to those of the ordinary method of moments variogram. Furthermore, from a filtering point of view, the variogram can be viewed in terms of a convolution of the data with a filter, which is computed fast in O(NLogN) number of operations in the frequency domain. We can also generate images of the filtered data corresponding to the nugget effect, sill and range of the variogram. This in turn provides additional tools to analyze the data further.  相似文献   

The COVID-19 pandemic and global environmental change: Emerging research needs     

Robert Barouki  Manolis Kogevinas  Karine Audouze  Kristine Belesova  Ake Bergman  Linda Birnbaum  Sandra Boekhold  Sebastien Denys  Celine Desseille  Elina Drakvik  Howard Frumkin  Jeanne Garric  Delphine Destoumieux-Garzon  Andrew Haines  Anke Huss  Genon Jensen  Spyros Karakitsios  Jana Klanova  Iida-Maria Koskela  Francine Laden  Paolo Vineis 《Chemie der Erde / Geochemistry》2011

The outbreak of COVID-19 raised numerous questions on the interactions between the occurrence of new infections, the environment, climate and health. The European Union requested the H2020 HERA project which aims at setting priorities in research on environment, climate and health, to identify relevant research needs regarding Covid-19. The emergence and spread of SARS-CoV-2 appears to be related to urbanization, habitat destruction, live animal trade, intensive livestock farming and global travel. The contribution of climate and air pollution requires additional studies. Importantly, the severity of COVID-19 depends on the interactions between the viral infection, ageing and chronic diseases such as metabolic, respiratory and cardiovascular diseases and obesity which are themselves influenced by environmental stressors. The mechanisms of these interactions deserve additional scrutiny. Both the pandemic and the social response to the disease have elicited an array of behavioural and societal changes that may remain long after the pandemic and that may have long term health effects including on mental health. Recovery plans are currently being discussed or implemented and the environmental and health impacts of those plans are not clearly foreseen. Clearly, COVID-19 will have a long-lasting impact on the environmental health field and will open new research perspectives and policy needs.  相似文献   

Glass-iron-clay interactions in a radioactive waste geological disposal: An integrated laboratory-scale experiment     

Guillaume de Combarieu  Michel L. Schlegel  Delphine NeffEddy Foy  Delphine VantelonPhilippe Barboux  Stéphane Gin 《Applied Geochemistry》2011,26(1):65-79

Glass-iron-clay setups were reacted at 90 °C for 6-18 months to investigate the coupled interactions between glass alteration, Fe corrosion and clay transformation. The reacted interfaces were probed at the microscopic level using complementary characterization methods (scanning electron microscopy coupled with energy-dispersive X-ray analysis, micro-Raman spectroscopy, micro X-ray diffraction, micro X-ray fluorescence spectroscopy, and micro X-ray absorption near-edge structure spectroscopy). The 10-μm thick Fe foil was fully corroded within 10 months, exposing glass to the pore solution. Iron corrosion led to the formation of a layer containing mostly magnetite, siderite and Fe-rich phyllosilicates with one tetrahedral and one octahedral sheet (TO) or two tetrahedral and one octahedral (TOT) sheet per layer. The clay in contact with this corrosion layer was enriched in siderite (FeCO₃). Glass alteration resulted in the formation of a gel layer whose thickness increased with reaction time (from 20 μm after 6 months to 80 μm after 18 months) and a thin layer of secondary precipitates that concentrated lanthanides, P, and Mo. Assuming conservative behavior of Zr, the Si molar concentration in the gel is about 57% that in the glass. Glass dissolution remained at a rate close to the initial dissolution rate r₀. The data are consistent with glass dissolution sustained by the uptake of dissolved Si and charge-compensating cations on secondary (corrosion) products, thus maintaining the gel porosity open and facilitating the leaching of easily soluble elements.  相似文献   

Digital Surface Modelling by Airborne Laser Scanning and Digital Photogrammetry for Glacier Monitoring   总被引：2，自引：0，他引：2  

Emmanuel P. Baltsavias  Etienne Favey  reas Bauder  Hermann Bosch  & Maria Pateraki 《The Photogrammetric Record》2001,17(98):243-273

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A Compilation of Silicon and Thirty One Trace Elements Measured in the Natural River Water Reference Material SLRS-4 (NRC-CNRC)   总被引：1，自引：0，他引：1  

Delphine Yeghicheyan  Jean Carignan  Michel Valladon  Martine Bouhnik Le  Coz  Florence Le Cornec  Maryse Castrec-Rouelle  Michel Robert  Luc Aquilina  Emmanuel Aubry  Carine Churlaud  Aline Dia  Samuel Deberdt  Bernard Dupré  Rémi Freydier  Gérard Gruau  Odile Hénin  Anne-Marie de  Kersabiec  Joël Macé  Luc Marin  Nicole Morin  Patrice Petitjean  Elodie Serrat 《Geostandards and Geoanalytical Research》2001,25(2-3):465-474

The natural river water certified reference material SLRS-4 (NRC-CNRC, National Research Council-Conseil National de Recherches Canada) has been routinely analysed for major and trace elements by six French laboratories. Most measurements were made using inductively coupled plasma-mass spectrometry. For silicon and thirty one trace elements (rare earth elements, Ag, B, Br, Cs, Ga, Ge, Li, P, Pd, Rb, Se, Th, Ti, Tl, W, Y and Zr), no certified values are assigned by NRC-CNRC. We propose some compilation values and related uncertainties according to the results obtained by the different laboratories.  相似文献   

A Pan African age for the HP-HT granulite gneisses of Zabargad island: implications for the early stages of the Red Sea rifting     

Joël R. Lancelot  Delphine Bosch 《Earth and Planetary Science Letters》1991,107(3-4)

Up to now the age of granulite gneisses intruded by the Zabargad mantle diapir has been an unsolved problem. These gneisses may represent either a part of the adjacent continental crust primarily differentiated during the Pan African orogeny, or new crust composed of Miocene clastic sediments deposited in a developing rift, crosscut by a diabase dike swarm and gabbroic intrusions, and finally metamorphosed and deformed by the mantle diapir. Previous geochronological results obtained on Zabargad island and Al Lith and Tihama-Asir complexes (Saudi Arabia) suggest an Early Miocene age of emplacement for the Zabargad mantle diapir during the early opening of the Red Sea rift. In contrast, SmNd and RbSr internal isochrons yield Pan African dates for felsic and basic granulites collected 500–600 m from the contact zone with the peridotites. Devoid of evidence for retrograde metamorphic, minerals from a felsic granulite provide well-defined RbSr and SmNd dates of 655 ± 8 and 699 ± 34 Ma for the HP-HT metamorphic event (10 kbar, 850°C). The thermal event related to the diapir emplacement is not recorded in the SmNd and RbSr systems of the studied gneisses; in contrast, the development of a retrograde amphibolite metamorphic paragenesis strongly disturbed the RbSr isotopic system of the mafic granulite. The initial¹⁴³Nd/¹⁴⁴Nd ratio of the felsic granulite is higher than the contemporaneous value for CHUR and is in agreement with other Nd isotopic data for samples of upper crust from the Arabian shield. This result suggests that source rocks of the felsic granulite were derived at 1.0 to 1.2 Ga from either an average MORB-type mantle or a local 2.2 Ga LREE-depleted mantle. Zabargad gneisses represent a part of the disrupted lower continental crust of the Pan African Afro-Arabian shield. During early stages of the Red Sea rifting in the Miocene, these Precambrian granulites were intruded and dragged upwards by a rising peridotite diapir.  相似文献   

The COVID-19 pandemic and global environmental change: Emerging research needs     

Robert Barouki  Manolis Kogevinas  Karine Audouze  Kristine Belesova  Ake Bergman  Linda Birnbaum  Sandra Boekhold  Sebastien Denys  Celine Desseille  Elina Drakvik  Howard Frumkin  Jeanne Garric  Delphine Destoumieux-Garzon  Andrew Haines  Anke Huss  Genon Jensen  Spyros Karakitsios  Jana Klanova  Paolo Vineis 《Chemie der Erde / Geochemistry》2013

The outbreak of COVID-19 raised numerous questions on the interactions between the occurrence of new infections, the environment, climate and health. The European Union requested the H2020 HERA project which aims at setting priorities in research on environment, climate and health, to identify relevant research needs regarding Covid-19. The emergence and spread of SARS-CoV-2 appears to be related to urbanization, habitat destruction, live animal trade, intensive livestock farming and global travel. The contribution of climate and air pollution requires additional studies. Importantly, the severity of COVID-19 depends on the interactions between the viral infection, ageing and chronic diseases such as metabolic, respiratory and cardiovascular diseases and obesity which are themselves influenced by environmental stressors. The mechanisms of these interactions deserve additional scrutiny. Both the pandemic and the social response to the disease have elicited an array of behavioural and societal changes that may remain long after the pandemic and that may have long term health effects including on mental health. Recovery plans are currently being discussed or implemented and the environmental and health impacts of those plans are not clearly foreseen. Clearly, COVID-19 will have a long-lasting impact on the environmental health field and will open new research perspectives and policy needs.  相似文献   

The three-point correlation function of galaxies: comparing halo occupation models with observations     

Yu Wang  Xiaohu Yang  H. J. Mo  Frank C. van den Bosch  YaoQuan Chu 《Monthly notices of the Royal Astronomical Society》2004,353(1):287-300

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Probing dark matter haloes with satellite kinematics     

Frank C. van den Bosch  Peder Norberg  H. J. Mo  Xiaohu Yang 《Monthly notices of the Royal Astronomical Society》2004,352(4):1302-1314

  相似文献