Golden Ratio Sinusoidal Sequences and the Multimode Pulsation of the δ Sct Star V784 Cassiopeiae     

JuanGarcíaEscudero 《中国天文和天体物理学报》2004,4(4):343-348

Non periodic ordered sequences obtained by production rules in formal grammars are applied to the analysis of the multi-periodicity of the δ-Scuti type variable star V784 Cas. An artificial light curve for V784 Cas is generated by a non deterministic derivation in a context-sensitive grammar by concatenation of two sinusoidal fragments following certain word sequences. The two basic building blocks represent temporal segments in a golden ratio and the number of long and short segments in a word are also in a golden ratio.  相似文献   

Numerical solution for consolidation and desiccation of soft soils     

Daniel T. C. Yao  Waldyr Lopes de Oliveira‐Filho  Xiao‐Chuan Cai  Dobroslav Znidarcic 《国际地质力学数值与分析法杂志》2002,26(2):139-161

The consolidation and desiccation behaviour of soft soils can be described by two time‐dependent non‐linear partial differential equations using the finite strain theory. Analytical solutions do not exist for these governing equations. In this paper, we develop efficient numerical methods and software for finding the numerical solutions. We introduce a semi‐implicit time integration scheme, and show numerically that our method converges. In addition, the numerical solution matches well with the experimental result. A boundary refinement method is also developed to improve the convergence and stability for the case of Neumann type boundary conditions. Interface governing equations are derived to maintain the continuity of consolidation and desiccation processes. This is useful because the soil column can undergo desiccation on top and consolidation on the bottom simultaneously. The numerical algorithms has been implemented into a computer program and the results have been verified with centrifuge test results conducted in our laboratory. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Calcification rate and temperature effects on Sr partitioning in coccoliths of multiple species of coccolithophorids in culture     

Heather M. Stoll  Christine M. Klaas  Ian Probert  Jorge Ruiz Encinar  J. Ignacio Garcia Alonso   《Global and Planetary Change》2002,34(3-4)

Five common placolith-bearing coccolithophorid algae—Gephyrocapsa oceanica, Coccolithus pelagicus, Calcidiscus leptoporus, Umbilicosphaera sibogae (var. sibogae and var. foliosa), and Emiliania huxleyi—were cultured to investigate controls on Sr partitioning in coccolith calcite. For identical temperature and media composition, Sr partitioning varies by more than 30% in exponential phase cultures of the five species and is linearly related to rates of calcite production/cell (ρ=0.91). Exponential phase culture experiments with three strains of C. leptoporus and six strains of G. oceanica at varying temperatures show variations in Sr partitioning of 20% and 30%, respectively. With C. leptoporus, Sr partitioning is equally correlated with temperature and calcification rate (ρ=0.8), which themselves are highly correlated; the slope of the relationship between D_Sr and calcification rate is comparable to that observed in all species at constant temperature. However, in G. oceanica, increased temperature appears to enhance Sr incorporation by up to 2% to 1.6% °C⁻¹ in the range of 15 to 30 °C. The strong influence of calcification rate on Sr partitioning may be useful for inferring past variations in coccolithophorid productivity from Sr partitioning in coccolith sediments if the influence of temperature on Sr partitioning can be resolved. Because the relationship between calcite production and Sr partitioning is linear, a proportional change in calcification should be expressed much more strongly in the Sr/Ca ratio of large species with rapid calcite production than in smaller species, which produce calcite more slowly. Consequently, it may be possible to separate temperature and calcification influences on coccolith Sr/Ca by separately analyzing Sr/Ca in species that produce calcite rapidly and those that produce calcite slowly, if both undergo comparable relative changes in calcification rates.  相似文献   

The HIPASS catalogue – II. Completeness, reliability and parameter accuracy     

M. A. Zwaan  M. J. Meyer  R. L. Webster  L. Staveley-Smith  M. J. Drinkwater  D. G. Barnes  R. Bhathal  W. J. G. de Blok  M. J. Disney  R. D. Ekers  K. C. Freeman  D. A. Garcia  B. K. Gibson  J. Harnett  P. A. Henning  M. Howlett  H. Jerjen  M. J. Kesteven  V. A. Kilborn  P. M. Knezek  B. S. Koribalski  S. Mader  M. Marquarding  R. F. Minchin  J. O'Brien  T. Oosterloo  M. J. Pierce  R. M. Price  M. E. Putman  E. Ryan-Weber  S. D. Ryder  E. M. Sadler  J. Stevens  I. M. Stewart  F. Stootman  M. Waugh  A. E. Wright 《Monthly notices of the Royal Astronomical Society》2004,350(4):1210-1219

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Hydrochemical assessment of surface water in watersheds near the Uranium Mining and Milling Facilities of Caldas,Brazil     

C. A. de Carvalho Filho  R. M. Moreira  B. F. Guimarães  V. V. M. Ferreira  L. M. L. A. Auler  H. E. L. Palmieri  A. F. Oliveira  P. H. Dutra 《Environmental Earth Sciences》2016,75(3):187

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Introduction to the special issue on adaptive flood risk management     

O&#;Hare  Paul  Cavan  Gina  Filho  Walter Leal 《Natural Hazards》2016,82(2):145-148

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Numerical modelling of Quaternary terrace staircase formation in the Ebro foreland basin,southern Pyrenees,NE Iberia          下载免费PDF全文

Kurt Martin Stange  Ronald T. Van Balen  Daniel Garcia‐Castellanos  Sierd Cloetingh 《Basin Research》2016,28(1):124-146

The southern foreland basin of the Pyrenees (Ebro basin) is an exorheic drainage basin since Late Miocene times. Remnants of an early exorheic Ebro drainage system are not preserved, but morphology provides evidence for the Pliocene–Quaternary drainage development. The incision history of the Ebro system is denoted by (i) extensive, low gradient pedimentation surfaces which are associated with the denudation of the southern Pyrenean piedmont around the Pliocene–Quaternary transition and (ii) deeply entrenched Quaternary river valleys. Presumably since the Middle Pleistocene fluvial incision intensified involving the formation of extensive terrace staircase in the Ebro basin. Terrace exposure dating in major Ebro tributary rivers indicates climate‐triggered terrace formation in response to glacial–interglacial climate and glacier fluctuations in the Pyrenean headwaters. The overall (semi)parallel longitudinal terrace profiles argue for progressive base level lowering for the whole Ebro drainage network. The landscape evolution model, TISC, is used to evaluate climatic, tectonic and base level scenarios for terrace staircase formation in the Ebro drainage system. Model simulations are compared with morpho‐climatic, tectonic and chronologic data. Results show that climatic fluctuations cause terrace formation, but the incision magnitudes and convergent terrace profiles predicted by this climate model scenario are not consistent with the (semi)parallel terraces in the Ebro basin. A model including previous (late Pliocene) uplift of the lower Ebro basin results in rapid base‐level lowering and erosion along the drainage network, small late stage incision magnitudes and terrace convergence, which are not in agreement with observations. Instead, continuous Quaternary uplift of both the Pyrenees and the Ebro foreland basin triggers (semi)parallel terrace staircase formation in southern Pyrenean tributary rivers in consistency with the observed longitudinal terrace profiles and Middle–Late Pleistocene incision magnitudes. Forward model simulations indicate that the present Ebro drainage system is actively incising, providing further evidence for uplift.  相似文献   

Platinum-group minerals in the Limoeiro Ni–Cu–(PGE) sulfide deposit,Brazil: the effect of magmatic and upper amphibolite to granulite metamorphic processes on PGM formation     

J. Mota-e-Silva  H. M. Prichard  C. F. Ferreira Filho  P. C. Fisher  I. McDonald 《Mineralium Deposita》2015,50(8):1007-1029

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The Northwest Geysers EGS Demonstration Project,California: Pre-stimulation Modeling and Interpretation of the Stimulation     

Jonny Rutqvist  Patrick F. Dobson  Julio Garcia  Craig Hartline  Pierre Jeanne  Curtis M. Oldenburg  Donald W. Vasco  Mark Walters 《Mathematical Geosciences》2015,47(1):3-29

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Multi-model climate projections of the main cyclogenesis hot-spots and associated winds over the eastern coast of South America     

de Jesus  Eduardo Marcos  da Rocha  Rosmeri Porfírio  Crespo  Natália Machado  Reboita  Michelle Simões  Gozzo  Luiz Felippe 《Climate Dynamics》2021,56(1-2):537-557

Climate Dynamics - In this study, multi-model ensembles are used to understand regional features of future climate trends of cyclones and associated winds in eastern South America. For this, we...  相似文献