Deep radio imaging of the SCUBA 8-mJy survey fields: submillimetre source identifications and redshift distribution     

R. J. Ivison  T. R. Greve  Ian Smail  J. S. Dunlop  N. D. Roche  S. E. Scott  M. J. Page  J. A. Stevens  O. Almaini  A. W. Blain  C. J. Willott  M. J. Fox  D. G. Gilbank  S. Serjeant  D. H. Hughes 《Monthly notices of the Royal Astronomical Society》2002,337(1):1-25

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The use of the Coulter Counter for the Determination of Marine Primary Productivity     

Cushing  D. H.; Nicholson  H. F.; Fox  G. P. 《ICES Journal of Marine Science》1968,32(1):131-151

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Site‐scale variability of streambank fluvial erodibility parameters as measured with a jet erosion test          下载免费PDF全文

E. R. Daly  G. A. Fox  H. K. Enlow  D. E. Storm  S. L. Hunt 《水文研究》2015,29(26):5451-5464

The erosion rate of cohesive streambanks is typically modelled using the excess shear stress equation, dependent on two erodibility parameters: critical shear stress and erodibility coefficient. The jet erosion test (JET) has become the most common method for estimating these erodibility parameters in situ. Typically, results from a few JETs are averaged to acquire a single set of parameters for characterizing a streambank layer; however, this may be inadequate for accurately characterizing erodibility. The research objectives were to investigate the variability of JET results from assumed homogeneous streambank layers and to estimate the number of JETs required to accurately characterize erodibility for use in predictive models. On three unique streambanks in Oklahoma and across a range of erodibility, 20 to 30 JETs were conducted over a span of three days at each site. Unique to this research, each JET was analysed using the Blaisdell, scour depth and iterative solutions. The required sample size to accurately estimate the erodibility parameters depended on the JET solution technique, the parameter being estimated, and the degrees of precision and confidence. Conducting three to five JETs per soil layer on a streambank typically provided an order of magnitude estimate of the erodibility parameters. Because the parameters were log‐normally distributed, using empirical equations to predict erosion properties based on soil characteristics will likely contain high uncertainty and thus should be used with caution. This study exemplifies the need to conduct in situ measurements using the JET to accurately characterize streambank resistance to fluvial erosion. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Taxonomic status and paleoecology of Rusingoryx atopocranion (Mammalia, Artiodactyla), an extinct Pleistocene bovid from Rusinga Island, Kenya     

J. Tyler Faith  Jonah N. Choiniere  Christian A. Tryon  Daniel J. Peppe  David L. Fox 《Quaternary Research》2011,75(3):697-707

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High‐resolution absorption spectroscopy of the circumgalactic medium of the Milky Way     

P. Richter  Aj. Fox  N. Ben Bekhti  M. T. Murphy  D. Bomans  S. Frank 《Astronomische Nachrichten》2014,335(1):92-98

In this article we discuss the importance of high‐resolution absorption spectroscopy for our understanding of the distribution and physical nature of the gaseous circumgalactic medium (CGM) that surrounds the Milky Way. Observational and theoretical studies indicate a high complexity of the gas kinematics and an extreme multi‐phase nature of the CGM in low‐redshift galaxies. High‐precision absorption‐line measurements of the Milky Way's gas environment thus are essential to explore fundamental parameters of circumgalactic gas in the local Universe, such as mass, chemical composition, and spatial distribution. We shortly review important characteristics of the Milky Way's CGM and discuss recent results from our multi‐wavelength observations of the Magellanic Stream. Finally, we discuss the potential of studying the warm‐hot phase of the Milky Way's CGM by searching for extremely weak [Fe X] λ 6374.5 Å and [Fe XIV] λ 5302.9 Å absorption in optical QSO spectra. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Radiative lifetimes of the second negative system of O₂⁺     

R.W. Wetmore  J.L. Fox  A. Dalgarno 《Planetary and Space Science》1984,32(9):1111-1113

The dipole moment of the A²Π_u?x²Π_g transition of O⁺₂ is calculated as a function of internuclear distance using ab initio methods. The band absorption oscillator strengths and band transition probabilities of the second negative system are derived and the resulting lifetimes are compared with experimental data. The high-lying v″ levels of the ground state may decay into low-lying v′ levels of the excited state. The corresponding radiative lifetimes are calculated.  相似文献   

Identification of fish echoes located at 65 km range by shore-based sonar     

Revie  J.; Weston  D. E.; Jones  F. R. Harden; Fox  G. P. 《ICES Journal of Marine Science》1990,46(3):313-324

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SN 2004A: another Type II-P supernova with a red supergiant progenitor     

M. A. Hendry  S. J. Smartt  R. M. Crockett  J. R. Maund  A. Gal-Yam †  D.-S. Moon  S. B. Cenko  D. W. Fox  R. P. Kudritzki  C. R. Benn  R. Østensen 《Monthly notices of the Royal Astronomical Society》2006,369(3):1303-1320

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The SCUBA 8-mJy survey – II. Multiwavelength analysis of bright submillimetre sources     

M. J.Fox  A.Efstathiou  M.Rowan-Robinson  J. S.Dunlop  S.Scott  S.Serjeant  R. G.Mann  S.Oliver  R. J.Ivison  A.Blain  O.Almaini  D.Hughes  C. J.Willott  M.Longair  A.Lawrence  J. A.Peacock 《Monthly notices of the Royal Astronomical Society》2002,331(4):839-852

We present the results of a multiwavelength study of the 19 most significant submillimetre (submm) sources detected in the SCUBA 8-mJy survey. As described in Scott et al. , this survey covers ≃260 arcmin² using the submillimetre camera SCUBA, to a limiting source detection limit   S _850 μm≃8 mJy  . One advantage of this relatively bright flux-density limit is that accurate astrometric positions are potentially achievable for every source using existing radio and/or millimetre-wave interferometers. However, an associated advantage is that spectral energy distribution (SED) based redshift constraints should be more powerful than in fainter submm surveys. Here we therefore exploit the parallel SCUBA 450-μm data, in combination with existing radio and Infrared Space Observatory ( ISO ) data at longer and shorter wavelengths to set constraints on the redshift of each source. We also analyse new and existing optical and near-infrared imaging of our SCUBA survey fields to select potential identifications consistent with these constraints. Our derived SED-based redshift constraints, and the lack of statistically significant associations with even moderately bright galaxies allow us to conclude that all 19 sources lie at   z >1  , and at least half of them apparently lie at   z >2  .  相似文献   

Food Habits of Large Nektonic Fishes: Trophic Linkages in Delaware Bay and the Adjacent Ocean     

K. W. Able  J. M. Morson  D. A. Fox 《Estuaries and Coasts》2018,41(3):866-883

Fish diets play a critical role in our understanding of aquatic trophic dynamics and are an important component in developing ecosystem-based approaches to fisheries management. Although large nektonic fishes exert top-down predator effects on the food web and typically support viable commercial and recreational fisheries, little is known about the diet of this guild. We evaluated the diets (6327 stomachs) of four nektonic predatory fishes (Pomatomus saltatrix [78–395 mm], Cynoscion regalis [91–520 mm], Morone americana [156–361 mm], and Morone saxatilis [82–785 mm]) in Delaware Bay and in the adjacent ocean. To assess ontogenetic, geographic, and interspecific variation in diets, observations from individual fish stomachs were clustered into species-size class groups, and dietary overlap was estimated using multivariate analyses. A shift in diet composition, as well as diversity, occurred along the estuarine gradient and into the adjacent ocean. Some prey were shared by most predators, including some crustaceans (dominated by Callinectes sapidus, mysids, and Palaemonetes spp.), fundulids (dominated by Fundulus heteroclitus), engraulids (dominated by Anchoa mitchilli), and clupeids (dominated by Brevoortia tyrannus). However, inter- and intra-specific variation in diet was observed as well. In particular, M. americana consumed fewer engraulids and clupeids, and many more and diverse types of invertebrates, while P. saltatrix consumed more clupeids and less invertebrates. The lack of overlap in diet between the four predators evaluated, and between size groups for each predator, supports previous evidence that these groups feed in trophic guilds defined by species and by size within a species. The highly variable diets for these predators suggest high resolution spatial data are necessary in order to quantify their most important prey and their role in coastal ecosystems.  相似文献