Potential impact of climate change on aquatic insects: A sensitivity analysis for European caddisflies (Trichoptera) based on distribution patterns and ecological preferences   总被引：1，自引：1，他引：0  

Daniel Hering  Astrid Schmidt-Kloiber  John Murphy  Sofie Lücke  Carmen Zamora-Muñoz  Manuel Jesús López-Rodríguez  Thomas Huber  Wolfram Graf 《Aquatic Sciences - Research Across Boundaries》2009,71(1):3-14

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Groundwater flow and capture zone analysis of the Central Passaic River Basin, New Jersey     

Fatoumata Barry  Duke Ophori  Jeffrey Hoffman  Robert Canace 《Environmental Geology》2009,56(8):1593-1603

Delineating capture zones of pumping wells is an important part of safe drinking water and well protection programs. Capture zones or contributing areas of a groundwater extraction well are the parts of the aquifer recharge areas from which the wells draw their water. Their extent and location depend on the hydrogeologic conditions such as groundwater recharge, pumping scenario and the aquifer properties such as hydraulic conductivity, porosity, heterogeneity of the medium and hydraulic gradient. Different methods of delineation can be used depending on the complexity of the hydrogeologic conditions. In this study, a 3-dimensional transient numerical MODFLOW model was developed for the Central Passaic River Basin (CPRB), and used with a MODPATH particle tracking code to determine 3-dimensional transient capture zones. Analytically calculated capture zones from previous studies at the site were compared with the new numerically simulated capture zones. The study results revealed that the analytical solution was more conservative, estimating larger capture zones than the numerical models. Of all the parameters that can impact the size, shape and location of a capture zone, the hydraulic conductivity is one of the most critical. Capture zones tend to be smaller in lower hydraulic conductivity areas.  相似文献   

Pelmatozoan echinoderms from the Cambrian–Ordovician transition of the Iberian Chains (NE Spain): early diversification of anchoring strategies     

Samuel Zamora  J. Javier Álvaro  Daniel Vizcaïno 《Swiss Journal of Geoscience》2009,102(1):43-55

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Preparing a seismic hazard model for Switzerland: the view from PEGASOS Expert Group 3 (EG1c)   总被引：1，自引：0，他引：1  

Roger M. W. Musson  Souad Sellami  Wolfgang Brüstle 《Swiss Journal of Geoscience》2009,102(1):107-120

The seismic hazard model used in the PEGASOS project for assessing earth-quake hazard at four NPP sites was a composite of four sub-models, each produced by a team of three experts. In this paper, one of these models is described in detail by the authors. A criticism sometimes levelled at probabilistic seismic hazard studies is that the process by which seismic source zones are arrived at is obscure, subjective and inconsistent. Here, we attempt to recount the stages by which the model evolved, and the decisions made along the way. In particular, a macro-to-micro approach was used, in which three main stages can be described. The first was the characterisation of the overall kinematic model, the “big picture” of regional seismogenesis. Secondly, this was refined to a more detailed seismotectonic model. Lastly, this was used as the basis of individual sources, for which parameters can be assessed. Some basic questions had also to be answered about aspects of the approach to modelling to be used: for instance, is spatial smoothing an appropriate tool to apply? Should individual fault sources be modelled in an intraplate environment? Also, the extent to which alternative modelling decisions should be expressed in a logic tree structure has to be considered.  相似文献   

Methodology and main results of seismic source characterization for the PEGASOS Project, Switzerland     

Kevin J. Coppersmith  Robert R. Youngs  Christian Sprecher 《Swiss Journal of Geoscience》2009,102(1):91-105

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Kinetic Monte Carlo method for simulating astrochemical kinetics: Test calculations of molecular hydrogen formation on interstellar dust particles     

A. G. Tsvetkov  V. I. Shematovich 《Solar System Research》2009,43(4):301-312

Molecular hydrogen formation on the surfaces of interstellar dust grains has been studied numerically. Different stochastic methods (analogue Monte Carlo methods, direct solutions of the chemical master equation, continuous-time random-walk simulations, etc.) have been recently applied to the astrochemistry of hydrogen formation; however, the computational efficiency of these approaches is usually low because they are extremely time consuming (Herbst and Shematovich, 2003). A kinetic version of the Monte Carlo method based on splitting by physical processes is presented in the study. Each of the basic physical processes—adsorption of atomic hydrogen on the surface, thermal diffusion, formation of molecular hydrogen, and hydrogen desorption from the surface-are considered as independent random Markovian-type processes and are simulated using stochastic algorithms. The suggested numerical model is computationally efficient allowing calculations to be held on model surfaces with up to 10⁶ active centers, which corresponds to interstellar grains of up to 0.4 μm in diameter. Test calculations of the efficiency of molecular hydrogen formation were held for the two models of the surfaces of interplanetary grains, namely, for the homogeneous surfaces of olivine and amorphous carbon. It was confirmed that the effective formation of molecular hydrogen in diffuse molecular clouds is possible only within a narrow range of dust-particle temperatures. A comparison with the numerical results of other authors is presented.  相似文献   

Radiation conditions of a mission to Jupiter and Europa     

M. V. Podzolko  I. V. Getselev  Yu. I. Gubar’  I. S. Veselovsky 《Solar System Research》2009,43(2):116-120

Radiation conditions in Jupiter’s environment and the plasma environment in interplanetary space during a Jupiter-Europa mission are estimated. The numerical modeling results can be used when planning the mission.  相似文献   

Pulkovo NEO page     

O. P. Bykov  A. N. Vershkov  A. V. Devyatkin  V. N. L’vov  R. I. Smekhacheva  S. D. Tserkmeister 《Solar System Research》2009,43(4):370-371

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Photometric function variations observed on the near side of the Moon: Mapping     

V. G. Kaidash  S. Yu. Gerasimenko  Yu. G. Shkuratov  N. V. Opanasenko  Yu. I. Velikodskii  V. V. Korokhin 《Solar System Research》2009,43(2):89-99

During two lunations, telescopic imaging of the near side of the Moon was performed at the Maidanak mountain observatory (Uzbekistan) with the use of digital cameras based on CMOS detectors. In different ranges of phase angles, the slope of the phase function of the lunar surface was mapped at a wavelength of 0.52 μm with the method of phase ratios. It has been shown that when the phase angle is gradually decreasing, the correlation between the phase-function slope and the albedo first disappears, and then even changes its sign at small phase angles.  相似文献   

Hierarchy of periodic solutions families of spatial Hill’s problem     

A. B. Batkhin  N. V. Batkhina 《Solar System Research》2009,43(2):178-183

Many modern space projects require the knowledge of orbits with certain properties. Most of these projects assume the motion of a space vehicle in the neighborhood of a celestial body, which in turn moves in the field of the Sun or another massive celestial body. A good approximation of this situation is Hill’s problem. This paper is devoted to the investigation of the families of spatial periodic solutions to the three-dimensional Hill’s problem. This problem is nonintegrable; therefore, periodic solutions are studied numerically. The Poincare theory of periodic solutions of the second kind is applied; either planar or vertical impact orbits are used as generating solutions.  相似文献