Topologies of Urban Politics and Protest     

Lynn A. Staeheli 《Urban geography》2013,34(4):445-447

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Dark matter dominance at all radii in the superthin galaxy UGC 7321     

Arunima Banerjee  Lynn D. Matthews  Chanda J. Jog 《New Astronomy》2010,15(1):89-95

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Evaluation of water‐use policies for baseflow recovery during droughts in an agricultural intensive karst watershed: Case study of the lower Apalachicola–Chattahoochee–Flint River Basin,southeastern United States          下载免费PDF全文

Sarmistha Singh  Subhasis Mitra  Puneet Srivastava  Ash Abebe  Lynn Torak 《水文研究》2017,31(21):3628-3644

The lower Apalachicola–Chattahoochee–Flint River Basin in the Southeast United States represents a major agricultural area underlain by the highly productive karstic Upper Floridan aquifer (UFA). During El Niño Southern Oscillation‐induced droughts, intense groundwater withdrawal for irrigation lowers streamflow in the Flint River due to its hydraulic connectivity with the UFA and threatens the habitat of the federally listed and endangered aquatic biota. This study assessed the compounding hydrologic effects of increased irrigation pumping during drought years (2010–2012) on stream–aquifer water exchange (stream–aquifer flux) between the Flint River and UFA using the United States Geological Survey modular finite element groundwater flow model. Principal component and K‐means clustering analyses were used to identify critical stream reaches and tributaries that are adversely affected by irrigation pumping. Additionally, the effectiveness of possible water restriction scenarios on stream–aquifer flux was also analysed. Moreover, a cost–benefit analysis of acreage buyout procedure was conducted for various water restriction scenarios. Results indicate that increased groundwater withdrawal in Water Year 2011 decreased baseflow in the lower Apalachicola–Chattahoochee–Flint River Basin, particularly, in Spring Creek, where irrigation pumping during April, June, and July changed the creek condition from a gaining to losing stream. Results from sensitivity analysis and simulated water restrictions suggest that reducing pumping in selected sensitive areas is more effective in streamflow recovery (approximately 78%) than is reducing irrigation intensity by a prescribed percentage of current pumping rates, such as 15% or 30%, throughout the basin. Moreover, analysis of acreage buyout indicates that restrictions on irrigation withdrawal can have significant impacts on stream–aquifer flux in the Basin, especially in critical watersheds such as Spring and Ichawaynochaway Creeks. The proposed procedure for ranking of stream reaches (sensitivity analysis) in this study can be replicated in other study areas/models. This study provides useful information to policymakers for devising alternate irrigation water withdrawal policies during droughts for maintaining flow levels in the study area.  相似文献   

Geocoding Large Population‐level Administrative Datasets at Highly Resolved Spatial Scales     

Sharon E. Edwards  Benjamin Strauss  Marie Lynn Miranda 《Transactions in GIS》2014,18(4):586-603

Using geographic information systems to link administrative databases with demographic, social, and environmental data allows researchers to use spatial approaches to explore relationships between exposures and health. Traditionally, spatial analysis in public health has focused on the county, ZIP code, or tract level because of limitations to geocoding at highly resolved scales. Using 2005 birth and death data from North Carolina, we examine our ability to geocode population‐level datasets at three spatial resolutions – zip code, street, and parcel. We achieve high geocoding rates at all three resolutions, with statewide street geocoding rates of 88.0% for births and 93.2% for deaths. We observe differences in geocoding rates across demographics and health outcomes, with lower geocoding rates in disadvantaged populations and the most dramatic differences occurring across the urban‐rural spectrum. Our results suggest that highly resolved spatial data architectures for population‐level datasets are viable through geocoding individual street addresses. We recommend routinely geocoding administrative datasets to the highest spatial resolution feasible, allowing public health researchers to choose the spatial resolution used in analysis based on an understanding of the spatial dimensions of the health outcomes and exposures being investigated. Such research, however, must acknowledge how disparate geocoding success across subpopulations may affect findings.  相似文献   

Eight-phase alkali feldspars: low-temperature cryptoperthite, peristerite and multiple replacement reactions in the Klokken intrusion   总被引：1，自引：0，他引：1  

Ian Parsons  John D. Fitz Gerald  Matthew T. Heizler  Lynn L. Heizler  Tim Ivanic  Martin R. Lee 《Contributions to Mineralogy and Petrology》2013,165(5):931-960

Eight feldspar phases have been distinguished within individual alkali feldspar primocrysts in laminated syenite members of the layered syenite series of the Klokken intrusion. The processes leading to the formation of the first four phases have been described previously. The feldspars crystallized as homogeneous sodian sanidine and exsolved by spinodal decomposition, between 750 and 600 °C, depending on bulk composition, to give fully coherent, strain-controlled braid cryptoperthites with sub-μm periodicities. Below ~500 °C, in the microcline field, these underwent a process of partial mutual replacement in a deuteric fluid, producing coarse (up to mm scale), turbid, incoherent patch perthites. We here describe exsolution and replacement processes that occurred after patch perthite formation. Both Or- and Ab-rich patches underwent a new phase of coherent exsolution by volume diffusion. Or-rich patches began to exsolve albite lamellae by coherent nucleation in the range 460–340 °C, depending on patch composition, leading to film perthite with ≤1 μm periodicities. Below ~300 °C, misfit dislocation loops formed, which were subsequently enlarged to nanotunnels. Ab-rich patches (bulk composition ~Ab₉₁Or₁An₈), in one sample, exsolved giving peristerite, with one strong modulation with a periodicity of ~17 nm and a pervasive tweed microtexture. The Ab-rich patches formed with metastable disorder below the peristerite solvus and intersected the peristerite conditional spinodal at ~450 °C. This is the first time peristerite has been imaged using TEM within any perthite, and the first time peristerite has been found in a relatively rapidly cooled geological environment. The lamellar periodicities of film perthite and peristerite are consistent with experimentally determined diffusion coefficients and a calculated cooling history of the intrusion. All the preceding textures were in places affected by a phase of replacement correlating with regions of extreme optical turbidity. We term this material ultra porous late feldspar (UPLF). It is composed predominantly of regions of microporous very Or-rich feldspar (mean Ab_2.5Or_97.4An_0.1) associated with very pure porous albite (Ab_97.0Or_1.6An_1.4) implying replacement below 170–90 °C, depending on degree of order. In TEM, UPLF has complex, irregular diffraction contrast similar to that previously associated with low-temperature albitization and diagenetic overgrowths. Replacement by UPLF seems to have been piecemeal in character. Ghost-like textural pseudomorphs of both braid and film parents occur. Formation of patch perthite, film perthite and peristerite occurred 10⁴–10⁵ year after emplacement, but there are no microtextural constraints on the age of UPLF formation.  相似文献   

A search for star formation around the Galactic halo B-type star PHL 346 with the 2dF spectrograph     

B. B. Lynn  P. L. Dufton  F. P. Keenan  N. C. Hambly  M. J. Irwin  G. Gilmore  W. R. J. Rolleston 《Monthly notices of the Royal Astronomical Society》2002,336(4):1287-1292

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Aerosol particle chemical characteristics measured from aircraft in the lower troposphere during ACE‐2     

Martina Schmeling  Lynn M. Russell  Carynelisa Erlick  Donald R. Collins  Haflidi Jonsson  Qing Wang  Peter Kregsamer  Christina Streli 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):185-200

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Aquatic and terrestrial humic materials: Editors Russell F. Christman and Egil T. Gjessing,Ann Arbor Science, 1983, 530 p., $39.95     

Lynn Margulis 《Geochimica et cosmochimica acta》1983,47(11):2064

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Coccolithophores as palaeoecological indicators for shifts of the ITCZ in the Cariaco Basin during the late Quaternary     

Kenneth N. J. M. Mertens  Matt Lynn  Mylene Aycard  Hui‐Ling Lin  Stephen Louwye 《第四纪科学杂志》2009,24(2):159-174

Coccoliths were studied from the ODP Hole 1002C and core PL07‐39PC in the Cariaco Basin. Increases in Emiliania huxleyi are synchronous with decreases of Gephyrocapsa oceanica and vice versa. A new index (GEX) based on the relative abundances of these two taxa is proposed, and correlates with various other proxies. It is shown that GEX can serve as upwelling proxy. This confirms that the Intertropical Convergence Zone shifted north during the Bølling/Allerød, south during the Younger Dryas and back north during the Preboreal. The upwelling proxy shows few discrepancies with the terrigenous record. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Using local knowledge to improve understanding of groundwater supplies in parts of arid South Australia     

Ian Clark  Lynn Brake 《GeoJournal》2009,74(5):441-450

Developing a good working knowledge of water in the landscape and the connectivity between surface and groundwater is germane to a resilient sustainable water supply to sustain human activities and a healthy environment, particularly in the drier parts of Australia. This paper presents a case study in the semi-arid Flinders Ranges of South Australia in which eliciting local knowledge from landholders was a key element in mapping surface and groundwater and investigating the connectivity between water resources. Local landholders provided a vital source of information to augment the limited scientific data initially available on groundwater resources. Groundwater recharge in the region comes from local rainfall onto individual unconnected groundwater catchments. In most of the region water supply seems to have been maintained over the longer term but there are a number of sites where former active springs are now dry or much reduced in size and water supplies from bores have substantially changed in quantity and quality. The involvement of landholders in the investigation of water resources encouraged them to consider the resource context of their stock watering points and incorporate more science into their understanding of the water resources that they rely on. This stimulated interest in investigating more about local water resources and changes in water management practices.  相似文献