CHANGING SPATIAL CHARACTERISTICS OF WILLAMETTE VALLEY FARMS   总被引：2，自引：0，他引：2  

Steven R. Holloway  Richard Wright  Mark Ellis 《The Professional geographer》2013,65(1):63-82

This article reflects on the racial configuration of urban space. Previous research tends to posit racial segregation and diversity as either endpoints on a continuum of racial dominance or mirror images of one another. We argue that segregation and diversity must be jointly understood; they are necessarily related, although not inevitably as binary opposites. Our view is that the neighborhood geographies of U.S. metropolitan areas are simultaneously and increasingly marked by both racial segregation and racial diversity. We offer an approach that classifies neighborhoods based jointly on their compositional diversity and their racial dominance, illustrated by an examination of the neighborhood racial structure of several large metropolitan areas for 1990 and 2000. Compositional diversity increased in all metropolitan areas in ways rendered visible by our approach, including a sharp reduction in the number of highly segregated white neighborhoods, transitioning mostly into moderately diverse yet still white-dominated neighborhoods, and a fourfold increase in the number of highly diverse neighborhoods. Even so, many highly segregated spaces remain, especially for whites and blacks. Latino-dominated spaces show a mix of persistence and emergence. Although compositional diversity is increasing, highly diverse neighborhoods are still rare and are the least persistent of all racial configurations. Our approach clearly demonstrates the “both/and”-ness of segregation and diversity.  相似文献   

A pre-shock event at Jupiter on 30 January 2001     

Karoly Szego  David T. Young  Bruce Barraclough  Andrew J. Coates  Michele K. Dougherty  Donald A. Gurnett  Andrea Opitz  Michelle F. Thomsen 《Planetary and Space Science》2006,54(2):200-211

In this paper we analyze a pre-shock event that we observed in the foot region of the quasi-parallel bow shock (BS) that the Cassini spacecraft crossed on 30 January 2001, at about 1030 UT. Before crossing the BS, the incoming solar wind first decelerated, and then the bulk velocity both of the proton and α components increased, the flow accelerated and decelerated, heated and cooled several times. We characterize the plasma in the foot using the data measured by the magnetometer, the radio and plasma wave science (RPWS) instrument, and the Cassini plasma spectrometer (CAPS) being carried onboard the Cassini spacecraft, and analyze the observations. We argue that the velocity and temperature changes can be caused by firehose instabilities excited by ions reflected from the shock. We investigate another possibility, shocklet formation, to account for the observed features, but conclude that this explanation seems to be less likely. In the foot we also identified both backstreaming electrons and ions and electrostatic waves in the 100-1000 Hz range very likely excited by the backstreaming electrons.  相似文献   

The shaping of planetary nebula Sh 2−188 through interactionwith the interstellar medium     

C. J. Wareing  T. J. O'Brien  Albert A. Zijlstra  K. B. Kwitter  J. Irwin  N. Wright  R. Greimel  J. E. Drew 《Monthly notices of the Royal Astronomical Society》2006,366(2):387-396

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Erratum: The radial velocity dispersion profile of the Galactic halo: constraining the density profile of the dark halo of the Milky Way     

Giuseppina Battaglia  Amina Helmi  Heather Morrison  Paul Harding  Edward W. Olszewski  Mario Mateo  Kenneth C. Freeman  John Norris  Stephen A. Shectman 《Monthly notices of the Royal Astronomical Society》2006,370(2):1055-1056

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Late Quaternary climate change record from two long sediment cores from Guaymas Basin,Gulf of California     

Heather Cheshire  Jürgen Thurow  Alexandra J. Nederbragt 《第四纪科学杂志》2005,20(5):457-469

Modern Guaymas Basin (Gulf of California, Mexico) is a region of high diatom productivity where exceptional preservation factors maintain biannually alternating sediment deposition as annual varves. New sediment cores from Guaymas Basin (MD02‐2512 and MD02‐2515) present the opportunity to construct climate records from below the last glacial period. A low‐resolution age model has been constructed from oxygen isotope analysis, correlation with other dated short piston cores from Guaymas Basin and an estimate of sedimentation rate. MD02‐2512 from eastern Guaymas Basin has an age range from the Holocene to late marine isotope stage 6 (MIS 6); MD02‐2515 from western Guaymas Basin has an age range from ～8000 to 40 000 yr. Shipboard analyses of colour reflectance, magnetic susceptibility and sediment density are combined with continuous X‐ray fluorescence scans to reconstruct a picture of glacial climate in the Gulf of California. Eastern Guaymas Basin is affected by glacial sea level fall, which results in a drastic change in productivity rates and sediment type. The laminated record of MIS 5 allows comparison with the Holocene, showing a similarity of sedimentation patterns during deglaciation and a series of very rapid variations just prior to the last glaciation. In western Guaymas Basin there are a series of Younger Dryas‐like events during the glacial, typified by low productivity and high terrigenous input. Long‐term climate and productivity changes appear to be caused by the southward displacement of the Subtropical High pressure zone. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

A detailed study of G35.2–0.7N: collimated outflows in a cluster of high-mass young stellar objects     

A. G. Gibb  M. G. Hoare  L. T. Little  M. C. H. Wright 《Monthly notices of the Royal Astronomical Society》2003,339(4):1011-1024

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Geology and stratigraphy of King crater, lunar farside   总被引：1，自引：0，他引：1  

David J Heather  Sarah K Dunkin 《Icarus》2003,163(2):307-329

Clementine and photographic data sets have been used to investigate the crustal stratigraphy and geology of King crater on the lunar farside (120°E, 5.5°N). Pre-existing topographic regimes or stress fields dominate many structures in the crater, which has excavated materials from depths of up to 14 km. The upper crust in the area is noritic anorthosite, grading to a more anorthositic signature with depth. A possible batholithic intrusion is also present in a 15-km-wide band, extending from the southern crater floor to at least 50 km north of King, and from near-surface levels down to at least the excavation depth of the crater. It is generally feldspathic, but is cut by mafic dykes now visible in the north wall. King also shows evidence for the presence of a cryptomare, exposed in regions of the peaks and in dark halo craters within the ejecta blanket. Localized olivine-bearing mineralogies are observed on the central peaks, suggesting isolated pockets of troctolitic mineralogies to have been present at 8- to 14-km depths. Copious volumes of crystalline melt produced from the impact event cover King’s floor to a maximum thickness of 30-60 m, and have pooled in a number of natural depressions outside of the main crater. The main pool in the pre-existing A1-Tusi crater has a minimum depth of 150 m. Domes on the crater floor are verified as nonvolcanic in origin, and did not act as a source for any of the lava-like materials in King.  相似文献   

Scientific rationale for the D-CIXS X-ray spectrometer on board ESA's SMART-1 mission to the Moon     

S.K Dunkin  M GrandeI Casanova  V FernandesD.J Heather  B KellettK Muinonen  S.S RussellR Browning  N WalthamD Parker  B KentC.H Perry  B SwinyardA Perry  J FeradayC Howe  K PhillipsG McBride  J HuovelinP Muhli  P.J HakalaO Vilhu  N ThomasD Hughes  H AlleyneM Grady  R LundinS Barabash  D BakerP.E Clark  C.D MurrayJ Guest  L.C d'UstonS Maurice  B FoingA Christou  C OwenP Charles  J LaukkanenH Koskinen  M KatoK Sipila  S NenonenM Holmstrom  N BhandariR Elphic  D Lawrence 《Planetary and Space Science》2003,51(6):435-442

The D-CIXS X-ray spectrometer on ESA's SMART-1 mission will provide the first global coverage of the lunar surface in X-rays, providing absolute measurements of elemental abundances. The instrument will be able to detect elemental Fe, Mg, Al and Si under normal solar conditions and several other elements during solar flare events. These data will allow for advances in several areas of lunar science, including an improved estimate of the bulk composition of the Moon, detailed observations of the lateral and vertical nature of the crust, chemical observations of the maria, investigations into the lunar regolith, and mapping of potential lunar resources. In combination with information to be obtained by the other instruments on SMART-1 and the data already provided by the Clementine and Lunar Prospector missions, this information will allow for a more detailed look at some of the fundamental questions that remain regarding the origin and evolution of the Moon.  相似文献   

“Stone Decay Hazards”     

Siegfried Siegesmund  Heather Viles  Thomas Weiss 《Environmental Geology》2004,46(3-4):303-304

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The HIPASS catalogue – I. Data presentation     

M. J. Meyer  M. A. Zwaan  R. L. Webster  L. Staveley-Smith  E. Ryan-Weber  M. J. Drinkwater  D. G. Barnes  M. Howlett  V. A. Kilborn  J. Stevens  M. Waugh  M. J. Pierce  R. Bhathal  W. J. G. de Blok  M. J. Disney  R. D. Ekers  K. C. Freeman  D. A. Garcia  B. K. Gibson  J. Harnett  P. A. Henning  H. Jerjen  M. J. Kesteven  P. M. Knezek  B. S. Koribalski  S. Mader  M. Marquarding  R. F. Minchin  J. O'Brien  T. Oosterloo  R. M. Price  M. E. Putman  S. D. Ryder  E. M. Sadler  I. M. Stewart  F. Stootman  A. E. Wright 《Monthly notices of the Royal Astronomical Society》2004,350(4):1195-1209

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