Dust filtration at gap edges: implications for the spectral energy distributions of discs with embedded planets     

W. K. M. Rice  Philip J. Armitage  Kenneth Wood  G. Lodato 《Monthly notices of the Royal Astronomical Society》2006,373(4):1619-1626

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Changes in the North Sea fish community: evidence of indirect effects of fishing?   总被引：7，自引：4，他引：7  

Daan  Niels; Gislason  Henrik; G. Pope  John; C. Rice  Jake 《ICES Journal of Marine Science》2005,62(2):177-188

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Effects of commercial dragging on sedimentary organic matter     

Lawrence M. Mayer  Daniel F. Schick  Robert H. Findlay  Donald L. Rice 《Marine environmental research》1991,31(4)

The effect of commercial dragging on sedimentary organic matter was examined in two field experiments using different types of gear. A heavy scallop dredge caused two types of organic matter translocation—some of the surficial organic matter was exported from the drag site and the remaining material was mixed into subsurface sediments. Phospholipid analysis indicated decreases in various classes of microbial, with relative increases in the contribution of anaerobic bacteria to the microbial community. An other trawl that largely remained above the sediment-water interface caused little change in organic matter profiles, although ⁷Be profiles suggest an export of the surficial horizon. Sediment mixing by some types of gear will likely result in burial of labile organic matter and hence may shift sediment metabolism toward microbial and anaerobic food chains.  相似文献   

Vacuum and Pressure Test Methods for Estimating Hydraulic Conductivity     

Jeffrey P. Orient  rzej Nazar  Richard C. Rice 《Ground Water Monitoring & Remediation》1987,7(1):49-50

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Distribution and provenance of the Baginton Sand and Gravel in the Wreake Valley,northern Leicestershire,England: Implications for inter-regional correlation     

John Rice 《第四纪科学杂志》1991,6(1):39-54

The Baginton Sand and Gravel is traced along the lower Wreake Valley as a continuous water-laid stratum at the base of the drift succession. Its properties closely resemble those previously described from the proto-Soar valley, namely an upward fining sequence and a composition dominated by pebbles of Triassic and Carboniferous origin. Such a provenance is consistent with the idea that the proto-Soar once followed a route eastwards past Melton Mowbray, and that the drainage along the lower Wreake Valley has been reversed in the course of Pleistocene times. However, the slope of the sand and gravel train appears to be to the west rather than the east, and the rockhead relief is also inconsistent with an eastward-flowing proto-Soar. Until this enigma is resolved, it would be imprudent to use the Baginton Sand and Gravel as the basis for inter-regional correlations. The issue is further complicated by the preservation at Brooksby of earlier interglacial or interstadial deposits whose temporal affinities remain unclear.  相似文献   

Infrared Spectroscopy of V4334 Sgr (Sakurai's Object)     

David K. Lynch  Richard J. Rudy  Ray W. Russell  Carl J. Rice  Stephan Mazuk  Catherine Venturini  Richard C. Puetter  Michael L. Sitko  Roc Cutri 《Astrophysics and Space Science》2002,279(1-2):57-64

IR spectroscopy and photometry in the 0.8–2.4 and 3–14 mregions are reported for seven dates between March 21 1998 and July20 2000 UT. The shorter wavelength region displays a smooth continuum increasing to longerwavelengths that is indicative of the Wien tail of a Planck function. Only theHe I 1.0830 line is present early and it shows a P-Cygni profile which laterdisappears. The long wave spectra show a smooth continuum between 3 and 13m that was well fit by a gray body at 1000 K. A weak, unidentifiedemission feature appears between 8 and 10 m.  相似文献   

River system discontinuities due to lateral inputs: generic styles and controls     

Robert I. Ferguson  Judith R. Cudden  Trevor B. Hoey  Stephen P. Rice 《地球表面变化过程与地形》2006,31(9):1149-1166

In alluvial river systems, lateral inputs of water and/or sediment at junctions or undercut hillsides can disrupt what would otherwise be smooth downstream trends in mainstream bed elevation, channel gradient, and bed grain size. Generic styles of mainstream response to lateral inputs are investigated using a one‐dimensional sediment routing model with multiple grain size fractions. Numerical experiments isolate the effects of three para‐meters: ratio of tributary to mainstream water flux (QR), ratio of tributary to mainstream bedload flux (FR), and ratio of tributary to mainstream bedload diameter (DR). The findings are not unduly sensitive to the choice of initial conditions or to approximations made in the model. The primary distinction is between junctions that aggrade, causing local profile convexity with interrupted downstream fining, and junctions that degrade. The immediate effects of aggradation extend further upstream than downstream, whereas degradation is much more subdued and has no upstream impact. Aggradation is typical of coarse inputs (DR > 2), and degradation of fine inputs (DR < 1), but very high ratios of QR to FR also promote degradation. Both aggrading and degrading junctions can lead to a change in mainstream bed grain size well below the junction, with higher ratios of QR to FR producing a coarser distal bed. The effect of a tributary reflects the interplay between additional bed load and additional discharge to transport it. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Use of dissolved chloride concentrations in tributary streams to support geospatial estimates of Cl contamination potential near Skiatook Lake,northeastern Oklahoma     

Cynthia A. Rice  Marvin M. Abbott  R.A. Zielinski 《Applied Geochemistry》2007

Releases of NaCl-rich (>100 000 mg/L) water that is co-produced from petroleum wells can adversely affect the quality of ground and surface waters. To evaluate produced water impacts on lakes, rivers and streams, an assessment of the contamination potential must be attainable using reliable and cost-effective methods. This study examines the feasibility of using geographic information system (GIS) analysis to assess the contamination potential of Cl to Skiatook Lake in the Hominy Creek drainage basin in northeastern Oklahoma. GIS-based predictions of affects of Cl within individual subdrainages are supported by measurements of Cl concentration and discharge in 19 tributaries to Skiatook Lake. Dissolved Cl concentrations measured in October, 2004 provide a snapshot of conditions assumed to be reasonably representative of typical inputs to the lake. Chloride concentrations ranged from 5.8 to 2300 mg/L and compare to a value of 34 mg/L in the lake. At the time of sampling, Hominy Creek provided 63% of the surface water entering the lake and 80% of the Cl load. The Cl load from the other tributaries is relatively small (<600 kg/day) compared to Hominy Creek (11 900 kg/day) because their discharges are relatively small (<0.44 m³/s) relative to Hominy Creek (3.1 m³/s). Examination of chemical components other than Cl in stream and lake waters indicates that many species, such as SO₄, cannot be used to assess contamination potential because they participate in a number of common biogeochemical processes that alter their concentrations.  相似文献   

Emerging technologies for in situ measurement of soil carbon     

Ronald J. Gehl  Charles W. Rice 《Climatic change》2007,80(1-2):43-54

Carbon sequestration in the terrestrial biosphere is critical to mitigating the increasing anthropogenic CO₂ content of the atmosphere. However, improved efficiency of methods for soil C measurement is important to better estimate terrestrial C inventories and fluxes at a regional and global scale. Laboratory based measurement of soil C involves intensive, time consuming, and costly methodology that limits applicability for large land areas. Recently, research efforts have focused on measuring soil C in situ using a variety of methods. These methods include Laser Induced Breakdown Spectroscopy (LIBS), Inelastic Neutron Scattering (INS), near-infrared spectroscopy (NIRS), and remote sensing. Basic fundamentals of each of these in situ methods for soil C determination are presented, and the differences among the methods and their relative advantages and disadvantages are discussed.  相似文献   

Effects of shoreline modification on a Northern Puget Sound beach: Microclimate and embryo mortality in surt smelt (Hypomesus pretiosus)     

Casimir A. Rice 《Estuaries and Coasts》2006,29(1):63-71

Human alteration of Puget Sound shorelines is extensive yet its ecological consequences are largely undocumented. This study evaluates differences between natural and heavily modified beaches in terms of microclimate and one aspect of biological condition. Electronic data laggers were placed at a tidal height of approximately 3.7 m (12 ft) above mean lower low water during July 16–20, 2001, to monitor light intensity, substrate and air temperatures, and humidity. Substrate samples were collected at the end of the monitoring period to evaluate condition and density of eggs from surf smelt (Hypomesus pretiosus), a forage fish species that spawns on gravel-sand beaches in the upper intertidal zone. The modified beach had significantly higher daily mean light intensity, air temperature and substrate temperature, and significantly lower daily mean relative humidity. Particularly striking were the differences in substrate temperature which, on the natural beach, ranged from 12.1°C to 18.2°C (mean=14.1°C) and on the modified beach ranged from 14.4°C to 29.4°C (mean=18.8°C). In addition to these different means and more extreme values, microclimate conditions on the modified beach were more variable, indicative of a less buffered environment. The proportion of smelt eggs containing live embryos on the altered beach was approximately half that of the natural beach.  相似文献