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81.
Markus Kissler-Patig 《Astrophysics and Space Science》2002,281(1-2):487-491
Old, metal-poor globular clusters trace the formation and evolution of early-type galaxies. Their are the best probes, at
low redshift, of the building-up of galaxy halos at high redshift. Their properties constrain the characteristics of their
progenitors. Recent results suggest that DLAs atz > 3 are the likely hosts for their formation. Finally, they shed light on the old, metal-poor halos probably present around
all early-type galaxies.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
82.
83.
Wolfgang?StinnesbeckEmail author Gerta?Keller Thierry?Adatte Markus?Harting Doris?Stüben Georg?Istrate Utz?Kramar 《International Journal of Earth Sciences》2004,93(6):1042-1065
CSDP core Yaxcopoil-1 was drilled to a depth of 1,511 m within the Chicxulub crater. An organic-rich marly limestone near the base of the hole (1,495 to 1,452 m) was deposited in an open marine shelf environment during the latest Cenomanian (uppermost Rotalipora cushmani zone). The overlying sequence of limestones, dolomites and anhydrites (1,495 to 894 m) indicates deposition in various carbonate platform environments (e.g., sabkhas, lagoons). A 100-m-thick suevite breccia (894–794 m) identifies the Chicxulub impact event. Above the suevite breccia is a dolomitic limestone with planktic foraminiferal assemblages indicative of Plummerita hantkeninoides zone CF1, which spans the last 300 ky of the Maastrichtian. An erosional surface 50 cm above the breccia/dolomite contact marks the K/T boundary and a hiatus. Limestones above this contact contain the first Tertiary planktic foraminifera indicative of an upper P. eugubina zone P1a(2) age. Another hiatus 7 cm upsection separates zone P1a(2) and hemipelagic limestones of planktic foraminiferal Zone P1c. Planktic foraminiferal assemblages of Zone Plc to P3b age are present from a depth of 794.04 up to 775 m. The Cretaceous carbonate sequence appears to be autochthonous, with a stratigraphic sequence comparable to late Cretaceous sediments known from outside the Chicxulub crater in northern and southern Yucatan, including the late Cenomanian organic-rich marly limestone. There is no evidence that these sediments represent crater infill due to megablocks sliding into the crater, such as major disruption of sediments, chaotic changes in lithology, overturned or deep dipping megablocks, major mechanical fragmentation, shock or thermal alteration, or ductile deformation. Breccia units that are intercalated in the carbonate platform sequence are intraformational in origin (e.g., dissolution of evaporites) and dykes are rare. Major disturbances of strata by the impact therefore appear to have been confined to within less than 60 km from the proposed impact center. Yaxcopoil-1 may be located outside the collapsed transient crater cavity, either on the upper end of an elevated and tilted horst of the terrace zone, or even outside the annular crater cavity. The Chicxulub site thus records a large impact that predates the K/T boundary impact and mass extinction. 相似文献
84.
Effectively communicating the complexity of climate change to the public is an important goal for the climate change research
community, particularly for those of us who receive public funds. The challenge of communicating the science of climate change
will be reduced if climate change researchers consider the links between personality types, communication tendencies and learning
preferences. Jungian personality type is one of many factors related to an individual’s preferred style of taking in and processing
information, i.e., preferred communication style. In this paper, we demonstrate that the Jungian personality type profile
of interdisciplinary, early career climate researchers is significantly different from that of the general population in the
United States. In particular, Ph.D. climate researchers tend towards Intuition and focus on theories and the “big picture”,
while the U.S. general population tends towards Sensing and focuses on concrete examples and experience. There are other differences
as well in the way the general public as a group prefers to take in information, make decisions, and deal with the outer world,
compared with the average interdisciplinary climate scientist. These differences have important implications for communication
between these two groups. We suggest that climate researchers will be more effective in conveying their messages if they are
aware of their own personality type and potential differences in preferred learning and communication styles between themselves
and the general public (and other specific audiences), and use this knowledge to more effectively target their audience. 相似文献
85.
E. Jehin D. Bockelée-Morvan N. Dello Russo J. Manfroid D. Hutsemékers H. Kawakita H. Kobayashi R. Schulz A. Smette J. Stüwe M. Weiler C. Arpigny N. Biver A. Cochran J. Crovisier P. Magain H. Rauer H. Sana R. J. Vervack H. Weaver J.-M. Zucconi 《Earth, Moon, and Planets》2009,105(2-4):343-349
We report on simultaneous optical and infrared observations of the Halley Family comet 8P/Tuttle performed with the ESO Very Large Telescope. Such multi-wavelength and coordinated observations are a good example of what can be done to support space missions. From high resolution optical spectroscopy of the CN (0,0) 388 nm and NH2 (0,9,0) 610 nm bands using UVES at UT2 we determined 12C/13C = 90 ± 10 and 14N/15N = 150 ± 20 in CN and we derived a nuclear spin temperature of NH3 of 29 ± 1 K. These values are similar to those found in Oort-Cloud and Jupiter Family comets. From low resolution long slit spectroscopy with FORS1 at UT2 we determined the CN, C3 and C2 production rates and the parent and daughter scale lengths up to 5.2 105 km tailward. From high resolution IR spectroscopy with CRIRES at UT1 we measured simultaneously the production rates and mixing ratios of H2O, HCN, C2H2, CH4, C2H6, and CH3OH. 相似文献
86.
Rainer Kaltenbaek Gerald Hechenblaikner Nikolai Kiesel Oriol Romero-Isart Keith C. Schwab Ulrich Johann Markus Aspelmeyer 《Experimental Astronomy》2012,34(2):123-164
Quantum physics challenges our understanding of the nature of physical reality and of space-time and suggests the necessity of radical revisions of their underlying concepts. Experimental tests of quantum phenomena involving massive macroscopic objects would provide novel insights into these fundamental questions. Making use of the unique environment provided by space, MAQRO aims at investigating this largely unexplored realm of macroscopic quantum physics. MAQRO has originally been proposed as a medium-sized fundamental-science space mission for the 2010 call of Cosmic Vision. MAQRO unites two experiments: DECIDE (DECoherence In Double-Slit Experiments) and CASE (Comparative Acceleration Sensing Experiment). The main scientific objective of MAQRO, which is addressed by the experiment DECIDE, is to test the predictions of quantum theory for quantum superpositions of macroscopic objects containing more than 108 atoms. Under these conditions, deviations due to various suggested alternative models to quantum theory would become visible. These models have been suggested to harmonize the paradoxical quantum phenomena both with the classical macroscopic world and with our notion of Minkowski space-time. The second scientific objective of MAQRO, which is addressed by the experiment CASE, is to demonstrate the performance of a novel type of inertial sensor based on optically trapped microspheres. CASE is a technology demonstrator that shows how the modular design of DECIDE allows to easily incorporate it with other missions that have compatible requirements in terms of spacecraft and orbit. CASE can, at the same time, serve as a test bench for the weak equivalence principle, i.e., the universality of free fall with test-masses differing in their mass by 7 orders of magnitude. 相似文献
87.
Flexible management of fishing rights and a sustainable fisheries industry in Europe 总被引:3,自引:0,他引:3
Although overexploitation of commercial fish stocks in European waters has been in the public debate now for more than 20 years, the European Union has so far failed to implement sustainable fisheries management. Millions in subsidies paid to the fishing industry have led to significant excess capacity in the fishing fleet. Various feeble attempts to stop overexploitation of marine resources have failed. The cause is that fishing policy is highly dominated by short-term socioeconomic interests. There is an urgent need for a new fisheries management system in Europe that supports reductions in the fishing fleet, increases responsibility among fishers and guarantees long-term conservation of natural marine resources.Transferable rights to fish have proved a reliable and effective means of creating incentives to conserve marine resources. By strengthening individual fishing rights under flexible quota management systems, the EU Member States could, within the Common Fisheries Policy, make a significant contribution to conserving fish stocks, to reducing excess capacity and to raising the profitability of the fisheries industry. A closer look at existing reservations against a flexible management system shows most of the objections to be overstated or capable of resolution. 相似文献
88.
L’Her Alexandre Reinert Markus Prants Sergey Carton Xavier Morvan Mathieu 《Ocean Dynamics》2021,71(5):601-612
Ocean Dynamics - The Eastern Kamchatka Current (EKC) is the western boundary current of the North Pacific subpolar gyre. Southeast of the Kamchatka Peninsula lies a large anticyclonic eddy, the... 相似文献
89.
Markus J. Aschwanden Jong Kwan Lee G. Allen Gary Michael Smith Bernd Inhester 《Solar physics》2008,248(2):359-377
The three-dimensional (3D) modeling of coronal loops and filaments requires algorithms that automatically trace curvilinear
features in solar EUV or soft X-ray images. We compare five existing algorithms that have been developed and customized to
trace curvilinear features in solar images: i) the oriented-connectivity method (OCM), which is an extension of the Strous pixel-labeling algorithm (developed by Lee,
Newman, and Gary); ii) the dynamic aperture-based loop-segmentation method (developed by Lee, Newman, and Gary); iii) unbiased detection of curvilinear structures (developed by Steger, Raghupathy, and Smith); iv) the oriented-direction method (developed by Aschwanden); and v) ridge detection by automated scaling (developed by Inhester). We test the five existing numerical codes with a TRACE image
that shows a bipolar active region and contains over 100 discernable loops. We evaluate the performance of the five codes
by comparing the cumulative distribution of loop lengths, the median and maximum loop length, the completeness or detection
efficiency, the accuracy, and flux sensitivity. These algorithms are useful for the reconstruction of the 3D geometry of coronal
loops from stereoscopic observations with the STEREO spacecraft, or for quantitative comparisons of observed EUV loop geometries
with (nonlinear force-free) magnetic field extrapolation models. 相似文献
90.
Gerhard Drolshagen Valeri Dikarev Markus Landgraf Holger Krag Wim Kuiper 《Earth, Moon, and Planets》2008,102(1-4):191-197
Over the last decade several new models for the sporadic interplanetary meteoroid flux have been developed. These include
the Divine-Staubach and the Dikarev model. They typically cover mass ranges from 10−18 g to 1 g and are applicable for model specific Sun distance ranges between 0.1 AU and 20 AU Near 1 AU averaged fluxes (over
direction and velocities) for all these models are tuned to the well established interplanetary model by Grün et al. However,
in many respects these models differ considerably. Examples are the velocity and directional distributions and the assumed
meteoroid sources. In this paper flux predictions by the various models to Earth orbiting spacecraft are compared. Main differences
are presented and analysed. The persisting differences even for near Earth space can be seen as surprising in view of the
numerous ground based (optical and radar) and in situ (captured Inter Stellar Dust Particles, in situ detectors and analysis
of retrieved hardware) measurements and simulations. 相似文献