Exploring the infrared/radio correlation at high redshift     

Edo Ibar  Michele Cirasuolo  Rob Ivison  Philip Best  Ian Smail  y Biggs  Chris Simpson  Jim Dunlop  Omar Almaini  Ross McLure  Sebastien Foucaud  Steve Rawlings 《Monthly notices of the Royal Astronomical Society》2008,386(2):953-962

  相似文献   

Spitzer observations of M33 and the hot star, H ii region connection     

Robert H. Rubin  Janet P. Simpson  Sean W. J. Colgan  Reginald J. Dufour  Gregory Brunner  Ian A. McNabb  Adalbert W. A. Pauldrach  Edwin F. Erickson  Michael R. Haas  Robert I. Citron 《Monthly notices of the Royal Astronomical Society》2008,387(1):45-62

  相似文献   

Radio imaging of the Subaru/XMM–Newton Deep Field – II. The 37 brightest radio sources     

Eleni Vardoulaki  Steve Rawlings  Chris Simpson  David G. Bonfield  R. J. Ivison  Eduardo Ibar 《Monthly notices of the Royal Astronomical Society》2008,387(2):505-535

We study the 37 brightest radio sources in the Subaru/ XMM–Newton Deep Field. We have spectroscopic redshifts for 24 of 37 objects and photometric redshifts for the remainder, yielding a median redshift z _med for the whole sample of   z _med≃ 1.1  and a median radio luminosity close to the 'Fanaroff–Riley type I/type II (FR I/FR II)' luminosity divide. Using mid-infrared (mid-IR) ( Spitzer MIPS 24 μm) data we expect to trace nuclear accretion activity, even if it is obscured at optical wavelengths, unless the obscuring column is extreme. Our results suggest that above the FR I/FR II radio luminosity break most of the radio sources are associated with objects that have excess mid-IR emission, only some of which are broad-line objects, although there is one clear low-accretion-rate object with an FR I radio structure. For extended steep-spectrum radio sources, the fraction of objects with mid-IR excess drops dramatically below the FR I/FR II luminosity break, although there exists at least one high-accretion-rate 'radio-quiet' QSO. We have therefore shown that the strong link between radio luminosity (or radio structure) and accretion properties, well known at z ∼ 0.1, persists to z ∼ 1. Investigation of mid-IR and blue excesses shows that they are correlated as predicted by a model in which, when significant accretion exists, a torus of dust absorbs ∼30 per cent of the light, and the dust above and below the torus scatters ≳1 per cent of the light.  相似文献   

Extension at the coast of the Makran subduction zone (Iran)     

Raphaël Normand  Guy Simpson  Abbas Bahroudi 《地学学报》2019,31(6):503-510

In the Makran subduction zone, earthquake focal mechanisms and geodetic data indicate that the deforming prism currently experiences N–S compression. However, palaeostress inversions performed on normal faults observed along the coast reveal local stress components consistent with N‐S extension. Previously proposed mechanisms such as gravitational collapse are not favoured by N–S compression and surface uplift. We propose that the observed kinematics result from transient stress reversals following large earthquakes. During the interseismic period (now), the region experiences N–S compression. However, following a large reverse rupture on the subduction interface, stresses in the inner wedge relax, enabling a brief period of extensional faulting before a compressive stress state is re‐established. This mechanism, also observed in other subduction zones, requires low overall stresses in the upper plate and that the margin ruptures in large megathrust earthquakes that result in nearly complete stress drops.  相似文献   

    

A. Schumacher  G. Böhnecke und C. Simpson 《Ocean Dynamics》1948,1(1):1

Ohne Zusammenfassung

---

Preface

  相似文献   

Energy input and dissipation in a temperate lake during the spring transition     

R. Iestyn Woolway  John H. Simpson 《Ocean Dynamics》2017,67(8):959-971

ADCP and temperature chain measurements have been used to estimate the rate of energy input by wind stress to the water surface in the south basin of Windermere. The energy input from the atmosphere was found to increase markedly as the lake stratified in spring. The efficiency of energy transfer (Eff), defined as the ratio of the rate of working in near-surface waters (RW) to that above the lake surface (P ₁₀), increased from ～0.0013 in vertically homogenous conditions to ～0.0064 in the first 40 days of the stratified regime. A maximum value of Eff～0.01 was observed when, with increasing stratification, the first mode internal seiche period decreased to match the diurnal wind period of 24 h. The increase in energy input, following the onset of stratification was reflected in enhancement of the mean depth-varying kinetic energy without a corresponding increase in wind forcing. Parallel estimates of energy dissipation in the bottom boundary layer, based on determination of the structure function show that it accounts for ～15% of RW in stratified conditions. The evolution of stratification in the lake conforms to a heating stirring model which indicates that mixing accounts for ～21% of RW. Taken together, these estimates of key energetic parameters point the way to the development of full energy budgets for lakes and shallow seas.  相似文献   

Higher-mode force response in multi-story strongback-braced frames     

Barbara G. Simpson Ph.D. 《地震工程与结构动力学》2020,49(14):1406-1427

Strongback-braced frames employ an essentially elastic steel truss, or strongback, that distributes demands more uniformly to delay or prevent story mechanisms. Because inertial forces are no longer limited by the formation of a story mechanism, strongback-braced frames can exhibit large elastic force demands, particularly in the higher modes. This paper characterizes the higher-mode force response of strongback-braced frames. Four-story archetypes were designed using nonlinear dynamic analyses to incorporate higher-mode force demands into the design process. The response of the archetypes was compared with that of reference buckling-restrained braced frames that were allowed to form story mechanisms. The force demands in the strongback were then described using equivalent-static forces to represent the inertial forces induced by the higher modes. Force demands in the strongback arise from a yielding first-mode ‘pivoting’ and elastic higher-mode ‘bending’ response. These higher-mode force demands are elastic, ill-constrained by the strength of the yield mechanism, and depend significantly on the choice of ground motion record used for the analysis. In remaining elastic in the higher modes, the strongback distributes demands more uniformly and mitigates the formation of story mechanisms. Consequently, design and analysis methods for strongback-braced frames need to include estimates for these near-elastic higher-mode force demands.  相似文献   

Mineral chemical provenance of Neolithic pitchstone artefacts from Ballygalley,County Antrim,Northern Ireland     

Jeremy Preston  Ian Meighan  Derek Simpson  Malcolm Hole 《Geoarchaeology》2002,17(3):219-236

A large number of pitchstone fragments and artefacts have recently been discovered at a Neolithic settlement site in Ballygalley, Co. Antrim, Northern Ireland. They consist predominantly of flakes and un‐reworked lumps and cores, with only one complete tool being found. Since no sources of workable pitchstone exist in Ireland, the source must have been the abundant pitchstone volcanic rocks found on the Hebridean Islands of northwest Scotland. The composition of the glass from a number of artefacts is highly siliceous, indicating that they were derived from pitchstones on the Island of Arran; pitchstones from all other Scottish locations are less silica‐rich. In addition, analysis of pyroxene and amphibole microcrystallites within the pitchstone suggests that the Corriegills area of Arran is the most likely source of the Ballygalley artefacts, although the precise outcrop has proved elusive. These finds, and others across Ireland, show that raw materials were being transported and probably traded over considerable distances despite there being suitable alternative sources of material for making tools (flint, etc.) available in the local area. This suggests that the pitchstone had a very specialist use. © 2002 Wiley Periodicals, Inc.  相似文献   

Copper,chromium, and lead in Manukau Harbour sediments     

J. Aggett  J. D. Simpson 《新西兰海洋与淡水研究杂志》2013,47(4):661-663

A limited survey was undertaken to determine the concentrations of copper, lead, and chromium in sediments of the upper Manukau Harbour, New Zealand. The concentrations of copper and chromium (33–70 and 70–107 μg g^‐1 respectively) were of the same order of magnitude as those reported for other New Zealand harbours. However, lead concentrations (98–247 μg g^‐1) were higher than those found for the other harbours. This may be a consequence of higher traffic densities in the surrounding area.  相似文献   

Current and Future Applications of 3-D Global Earth-Ionosphere Models Based on the Full-Vector Maxwell’s Equations FDTD Method     

Jamesina J. Simpson 《Surveys in Geophysics》2009,30(2):105-130

Advances in computing technologies in recent decades have provided a means of generating and performing highly sophisticated computational simulations of electromagnetic phenomena. In particular, just after the turn of the twenty-first century, improvements to computing infrastructures provided for the first time the opportunity to conduct advanced, high-resolution three-dimensional full-vector Maxwell’s equations investigations of electromagnetic propagation throughout the global Earth-ionosphere spherical volume. These models, based on the finite-difference time-domain (FDTD) method, are capable of including such details as the Earth’s topography and bathymetry, as well as arbitrary horizontal/vertical geometrical and electrical inhomogeneities and anisotropies of the ionosphere, lithosphere, and oceans. Studies at this level of detail simply are not achievable using analytical methods. The goal of this paper is to provide an historical overview and future prospectus of global FDTD computational research for both natural and man-made electromagnetic phenomena around the world. Current and future applications of global FDTD models relating to lightning sources and radiation, Schumann resonances, hypothesized earthquake precursors, remote sensing, and space weather are discussed.

Jamesina J. SimpsonEmail:

  相似文献