On the formation of star clusters in the merger NGC 6240     

A. Pasquali  R. de Grijs  J. S. Gallagher 《Monthly notices of the Royal Astronomical Society》2003,345(1):161-174

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An examination of some uncertainties associated with estimates of sedimentation rates and tectonic subsidence   总被引：1，自引：0，他引：1  

KERRY Gallagher 《Basin Research》1989,2(2):97-114

Abstract The sensitivity of backstripping calculations (sedimentation rates and tectonic subsidence) to uncertainties regarding porosity reduction is examined. Models simulating compaction and externally sourced cementation are considered to provide first-order bounds on the thickness and mass changes for individual sedimentary units. These bounds can be used to estimate uncertainties in sedimentation rate and subsidence estimates. With these models, the timing of cement development can be regarded as unimportant for backstripping calculations. Calculations have been made to evaluate the effect on backstripping calculations of uncertainties in sediment porosity, density and the mechanisms of porosity reduction. Departures from theoretically predicted subsidence curves of the order of 100 m or so have been variously interpreted as the result of fluctuations or uncertainties in sea-level, palaeobathymetry, tectonic stress, sedimentation rates and stratigraphic age. Two examples are given to illustrate that such departures may occur in some subsidence curves merely as a result of imprecise assumptions regarding porosity reduction. Consideration should be given to the uncertainties in models for porosity reduction when using subsidence curves to infer second order tectonic influence during basin evolution.  相似文献   

High-frequency oscillations in a solar active region coronal loop     

D.R. Williams  K.J.H. Phillips  P. Rudawy  M. Mathioudakis  P.T. Gallagher  E. O'Shea  F.P. Keenan  P. Read  B. Rompolt 《Monthly notices of the Royal Astronomical Society》2001,326(2):428-436

The Solar Eclipse Corona Imaging System (SECIS) was used to record high-cadence observations of the solar corona during the total solar eclipse of 1999 August 11. During the 2 min 23.5 s of totality, 6364 images were recorded simultaneously in each of the two channels: a white light channel, and the Fe  xiv (5303 Å) 'green line' channel ( T ∼2 MK) . Here we report initial results from the SECIS experiment, including the discovery of a 6-s intensity oscillation in an active region coronal loop.  相似文献   

A Marine Isotope Stage 4 age for Pleistocene raised beach deposits near Fethard,southern Ireland          下载免费PDF全文

Colman Gallagher  Matt W. Telfer  Colm Cofaigh 《第四纪科学杂志》2015,30(8):754-763

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Erratum to: Impacts of rising air temperatures and emissions mitigation on electricity demand and supply in the United States: a multi-model comparison     

James McFarland  Yuyu Zhou  Leon Clarke  Patrick Sullivan  Jesse Colman  Wendy S. Jaglom  Michelle Colley  Pralit Patel  Jiyon Eom  Son H. Kim  G. Page Kyle  Peter Schultz  Boddu Venkatesh  Juanita Haydel  Charlotte Mack  Jared Creason 《Climatic change》2015,132(4):739-739

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Pollutant Plume Dispersion in the Atmospheric Boundary Layer over Idealized Urban Roughness     

Colman C. C. Wong  Chun-Ho Liu 《Boundary-Layer Meteorology》2013,147(2):281-300

The Gaussian model of plume dispersion is commonly used for pollutant concentration estimates. However, its major parameters, dispersion coefficients, barely account for terrain configuration and surface roughness. Large-scale roughness elements (e.g. buildings in urban areas) can substantially modify the ground features together with the pollutant transport in the atmospheric boundary layer over urban roughness (also known as the urban boundary layer, UBL). This study is thus conceived to investigate how urban roughness affects the flow structure and vertical dispersion coefficient in the UBL. Large-eddy simulation (LES) is carried out to examine the plume dispersion from a ground-level pollutant (area) source over idealized street canyons for cross flows in neutral stratification. A range of building-height-to-street-width (aspect) ratios, covering the regimes of skimming flow, wake interference, and isolated roughness, is employed to control the surface roughness. Apart from the widely used aerodynamic resistance or roughness function, the friction factor is another suitable parameter that measures the drag imposed by urban roughness quantitatively. Previous results from laboratory experiments and mathematical modelling also support the aforementioned approach for both two- and three-dimensional roughness elements. Comparing the UBL plume behaviour, the LES results show that the pollutant dispersion strongly depends on the friction factor. Empirical studies reveal that the vertical dispersion coefficient increases with increasing friction factor in the skimming flow regime (lower resistance) but is more uniform in the regimes of wake interference and isolated roughness (higher resistance). Hence, it is proposed that the friction factor and flow regimes could be adopted concurrently for pollutant concentration estimate in the UBL over urban street canyons of different roughness.  相似文献   

Active-Region Monitoring and Flare Forecasting – I. Data Processing and First Results     

Gallagher  Peter T.  Moon  Y.-J.  Wang  Haimin 《Solar physics》2002,209(1):171-183

This paper discusses a near real-time approach to solar active-region monitoring and flare prediction using the Big Bear Solar Observatory Active Region Monitor (ARM). Every hour, ARM reads, calibrates, and analyses a variety of data including: full-disk Hα images from the Global Hα Network; EUV, continuum, and magnetogram data from the Solar and Heliospheric Observatory (SOHO); and full-disk magnetograms from the Global Oscillation Network Group (GONG). For the first time, magnetic gradient maps derived from GONG longitudinal magnetograms are now available on-line and are found to be a useful diagnostic of flare activity. ARM also includes a variety of active-region properties from the National Oceanic and Atmospheric Administration's Space Environment Center, such as up-to-date active-region positions, GOES 5-min X-ray data, and flare-to-region identifications. Furthermore, we have developed a Flare Prediction System which estimates the probability for each region to produce C-, M-, or X-class flares based on nearly eight years of NOAA data from cycle 22. This, in addition to BBSO's daily solar activity reports, has proven a useful resource for activity forecasting. Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1023/A:1020950221179  相似文献   

Mantle hotspots, plumes and regional tectonics as causes of intraplate magmatism     

C. J. Hawkesworth  K. Gallagher 《地学学报》1993,5(6):552-559

In continental areas it is often difficult to determine the cause of intraplate magmatism. Large volumes of magma, high eruption rates, and the presence of a hotspot trace on the adjacent ocean floor, are all evidence for the presence of an anomalously hot mantle. However, in many continental magmas there are chemical variations with time which are inferred to reflect changes from asthenospheric to predominantly lithospheric source regions, or vice versa. It is argued that these chemical characteristics constrain whether magmatism was triggered by the emplacement of a mantle plume, or by lithospheric extension.  相似文献   

The effects of age on red giant metallicities derived from the near-infrared Ca ii triplet     

A. A. Cole  T. A. Smecker-Hane  E. Tolstoy  T. L. Bosler  J. S. Gallagher 《Monthly notices of the Royal Astronomical Society》2004,347(2):367-379

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Displacement of X-ray sources from star clusters in starburst galaxies   总被引：1，自引：0，他引：1  

P. Kaaret  A. Alonso-Herrero  J. S. Gallagher  III    G. Fabbiano  A. Zezas  M. J. Rieke 《Monthly notices of the Royal Astronomical Society》2004,348(2):L28-L32

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