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171.
Parameter constraints for flat cosmologies from cosmic microwave background and 2dFGRS power spectra
Will J. Percival Will Sutherland John A. Peacock Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Stephen Moody Peder Norberg Bruce A. Peterson Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,337(3):1068-1080
172.
The 2dF Galaxy Redshift Survey: the dependence of galaxy clustering on luminosity and spectral type 总被引:1,自引:0,他引:1
Peder Norberg Carlton M. Baugh Ed Hawkins Steve Maddox Darren Madgwick Ofer Lahav Shaun Cole Carlos S. Frenk Ivan Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Ian Lewis Stuart Lumsden John A. Peacock Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,332(4):827-838
We investigate the dependence of galaxy clustering on luminosity and spectral type using the 2dF Galaxy Redshift Survey (2dFGRS). Spectral types are assigned using the principal-component analysis of Madgwick et al. We divide the sample into two broad spectral classes: galaxies with strong emission lines ('late types') and more quiescent galaxies ('early types'). We measure the clustering in real space, free from any distortion of the clustering pattern owing to peculiar velocities, for a series of volume-limited samples. The projected correlation functions of both spectral types are well described by a power law for transverse separations in the range 2<( σ / h -1 Mpc)<15 , with a marginally steeper slope for early types than late types. Both early and late types have approximately the same dependence of clustering strength on luminosity, with the clustering amplitude increasing by a factor of ∼2.5 between L * and 4 L *. At all luminosities, however, the correlation function amplitude for the early types is ∼50 per cent higher than that of the late types. These results support the view that luminosity, and not type, is the dominant factor in determining how the clustering strength of the whole galaxy population varies with luminosity. 相似文献
173.
174.
Meredith R.W. Stanic S.J. Goodman R.R. Kennedy E.T. Pace N.G. 《Oceanic Engineering, IEEE Journal of》2004,29(2):524-533
Dynamic ocean processes produce small thermal variations that induce spatial and temporal variability in the ocean's index of refraction and in the spatial scale along an acoustic propagation path. This paper reports measurements and analysis of thermal microstructure effects on ping-to-ping amplitude and phase variability of shallow-water direct-path acoustic propagation in the 20-200 kHz frequency range. These measurements were conducted during a joint experiment conducted by the Naval Research Laboratory and the North Atlantic Treaty Organization Supreme Allied Commander Atlantic (SACLANT) Undersea Research Centre, La Spezia, Italy, in 8 m of water off American Beach, located between Pisa and Livorno, Italy. Experimental observations are compared with predictions for isotropic and anisotropic turbulence, as well as for sea-surface swell. Measured phase and log-amplitude variances coincide with predictions and are relatively insensitive to weak water-column stability. The sea-surface swell dominates phase variances for this data and turbulence dominates log-amplitude variances. These results provide a reasonable lower limit on high-frequency ping-to-ping amplitude and on phase variability produced by benign shallow-water thermal fluctuations. 相似文献
175.
Gavin Musgrovl 《中国地理科学(英文版)》1994,(3)
金玉献CHINA'SRADICALBIRTHCONTROLPOLICYANDIMPLICATIONSFORINDIA¥GavinMusgrovl(TrinityandAllSointsCollege,ACollegeofLeedsUniversity... 相似文献
176.
Roberto De Propris Matthew Colless John A. Peacock Warrick J. Couch Simon P. Driver Michael L. Balogh Ivan K. Baldry Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Chris Collins Nicholas Cross Gavin Dalton George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Edward Hawkins Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Peder Norberg Will Percival Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,351(1):125-132
177.
Groundwater-flow models depend on hydraulic head and flux observations for evaluation and calibration. A different type of observation—change in storage measured using repeat microgravity—can also be used for parameter estimation by simulating the expected change in gravity from a groundwater model and including the observation misfit in the objective function. The method is demonstrated using new software linked to MODFLOW input and output files and field data from the vicinity of the All American Canal in southeast California, USA. Over a 10-year period following lining of the previously highly permeable canal with concrete, gravity decreased by over 100 μGal (equivalent to about 2.5 m of free-standing water) at some locations as seepage decreased and the remnant groundwater mound dissipated into the aquifer or was removed by groundwater pumping. Simulated gravity from a MODFLOW model closely matched observations, and repeat microgravity data proved useful for constraining both hydraulic conductivity and specific yield estimates. Specific yield estimated using the infinite-horizontal slab approximation agreed well with model-derived values, and the departure from the linear, flat-water-table approximation was small, less than 2%, despite relatively large and dynamic water-table slope. First-order second-moment parameter uncertainty analysis shows reduction in uncertainty for all hydraulic conductivity and specific yield parameter estimates with the addition of repeat microgravity data, as compared to drawdown data alone. 相似文献
178.
Tracy L. Kijewski-Correa Andrew B. Kennedy Alexandros A. Taflanidis David O. Prevatt 《Natural Hazards》2018,93(2):627-659
The old potable water network in Byblos city is provided mainly from Ibrahim River nearby. Located in a seismic region, the aging network needs to tolerate seismic threats; thus, damage to the potable water network needs to be assessed. Therefore, first, enhancing infrastructure resilience is briefly discussed, noting briefly the need to bridge specifically between heritage risk management and engineering. Second, Byblos potable water network, seismicity, and geology are detailed. Third, the potable water network damage assessment methodology is presented. It encompasses hazard assessment, network inventory, damage functions, and model development. Data and maps are prepared using the Geographic Information System and then modeled in Ergo platform to obtain the damage to buried pipelines in the event of likely earthquake scenarios. Ergo is updated to consider recommended ground motion prediction equations (GMPEs) for the Middle East region, to consider amplification of the peak ground velocity in hazard maps due to different soil types, and to consider adequate fragility functions. Moreover, different Byblos geotechnical maps, landslide hazard, and liquefaction are investigated and embedded. Damage results to pipelines are dependent on the hazard maps obtained using different GMPEs and geotechnical maps. Asbestos cement pipelines will be most damaged, followed by polyethylene and then by ductile iron. Finally, recommendations are offered to consider an improved sustainable rehabilitation solution. The study provides a better understanding of Byblos potable water network and allows the establishment of a sustainable and resilience-to-earthquake preparedness strategy and recovery plan. 相似文献
179.
Seasonal controls on sediment transport and deposition in Lake Ohau,South Island,New Zealand: Implications for a high‐resolution Holocene palaeoclimate reconstruction 下载免费PDF全文
Heidi A. Roop Gavin B. Dunbar Richard Levy Marcus J. Vandergoes Alexander L. Forrest Sharon L. Walker Jennifer Purdie Phaedra Upton James Whinney 《Sedimentology》2015,62(3):826-844
Laminated sediments in Lake Ohau, Mackenzie Basin, New Zealand, offer a potential high‐resolution climate record for the past 17 kyr. Such records are particularly important due to the relative paucity of detailed palaeoclimate data from the Southern Hemisphere mid‐latitudes. This paper presents outcomes of a study of the sedimentation processes of this temperate lake setting. Hydrometeorological, limnological and sedimentological data were collected over a 14 month period between 2011 and 2013. These data indicate that seasonality in the hydrometeorological system in combination with internal lake dynamics drives a distinct seasonal pattern of sediment dispersal and deposition on a basin‐wide scale. Sedimentary layers that accumulate proximal to the lake inflow at the northern end of the lake form in response to discrete inflow events throughout the year and display an event stratigraphy. In contrast, seasonal change in the lake system controls accumulation of light (winter) and dark (summer) laminations at the distal end of the lake, resulting in the preservation of varves. This study documents the key processes influencing sediment deposition throughout Lake Ohau and provides fundamental data for generating a high‐resolution palaeoclimate record from this temperate lake. 相似文献
180.
Hans C. Oskierski Judy G. Bailey Eric M. Kennedy Geraldine Jacobsen Paul M. Ashley Bogdan Z. Dlugogorski 《Mineralium Deposita》2013,48(4):525-541
Nodular, cryptocrystalline, weathering-derived magnesite deposits in the New England Orogen, Australia, provide a significant source of high-purity magnesite. Common textural features and related isotopic fingerprints indicate a close genetic relationship between weathering-derived magnesite deposits hosted by ultramafic rocks at Attunga and by sediments at Kunwarara while silica-carbonate rock alteration and rare hydrothermal magnesite vein deposits reflect contrasting conditions of formation. Localised weathering of carbonates in a soil environment shifts stable isotopic composition towards low δ 13C and high δ 18O typical for weathering-derived magnesites while intrusion-related fluids do not significantly change the isotopic composition of affected carbonates. At Attunga, magnesite consists of irregular, nodular veins and masses filling faults and cracks in the weathered serpentinite host rock as well as soft powdery magnesite in pervasive serpentinite alteration zones. The high-grade magnesite at Attunga can be contaminated by amorphous silica and serpentine relicts but does not contain dolomite or ferroan magnesite as observed for its hydrothermal equivalent, the Piedmont magnesite deposit, or other widespread deposits of silica-carbonate rock in the Great Serpentinite Belt. Heavy δ 18O values are compatible with a supergene formation from meteoric waters while low δ 13C suggests C3-photosynthetic plants as the predominant source of carbon for the Attunga magnesites. We infer that weathering-derived, nodular magnesite deposits hosted in ultramafic rocks like the Attunga magnesite deposit have formed in a two-step process involving the hypogene formation of a pre-cursor magnesite deposit and complete supergene overprinting by meteoric waters that acquired carbon from percolation through soil. 相似文献