Constraining late stage melt-peridotite interaction in the lithospheric mantle of southern Ethiopia: evidence from lithium elemental and isotopic compositions     

Alemayehu  Melesse  Zhang  Hong-Fu  Seitz  Hans-Michael 《Mineralogy and Petrology》2017,111(5):777-792

Mineralogy and Petrology - Lithium (Li) elemental and isotopic compositions for mineral separates of coexisting olivine, orthopyroxene and clinopyroxene of mantle xenoliths from the Quaternary...  相似文献   

Linking the Abundance of Estuarine Fish and Crustaceans in Nearshore Waters to Shoreline Hardening and Land Cover     

Matthew S. Kornis  Denise Breitburg  Richard Balouskus  Donna M. Bilkovic  Lori A. Davias  Steve Giordano  Keira Heggie  Anson H. Hines  John M. Jacobs  Thomas E. Jordan  Ryan S. King  Christopher J. Patrick  Rochelle D. Seitz  Heather Soulen  Timothy E. Targett  Donald E. Weller  Dennis F. Whigham  Jim UphoffJr 《Estuaries and Coasts》2017,40(5):1464-1486

Human alteration of land cover (e.g., urban and agricultural land use) and shoreline hardening (e.g., bulkheading and rip rap revetment) are intensifying due to increasing human populations and sea level rise. Fishes and crustaceans that are ecologically and economically valuable to coastal systems may be affected by these changes, but direct links between these stressors and faunal populations have been elusive at large spatial scales. We examined nearshore abundance patterns of 15 common taxa across gradients of urban and agricultural land cover as well as wetland and hardened shoreline in tributary subestuaries of the Chesapeake Bay and Delaware Coastal Bays. We used a comprehensive landscape-scale study design that included 587 sites in 39 subestuaries. Our analyses indicate shoreline hardening has predominantly negative effects on estuarine fauna in water directly adjacent to the hardened shoreline and at the larger system-scale as cumulative hardened shoreline increased in the subestuary. In contrast, abundances of 12 of 15 species increased with the proportion of shoreline comprised of wetlands. Abundances of several species were also significantly related to watershed cropland cover, submerged aquatic vegetation, and total nitrogen, suggesting land-use-mediated effects on prey and refuge habitat. Specifically, abundances of four bottom-oriented species were negatively related to cropland cover, which is correlated with elevated nitrogen and reduced submerged and wetland vegetation in the receiving subestuary. These empirical relationships raise important considerations for conservation and management strategies in coastal environments.  相似文献   

No-Purge Groundwater Sampling for PFAS     

Melissa Armstrong  Matthew J. Seitz  Fern Beetle-Moorcroft  David S. Lipson 《Ground water》2020,58(6):872-876

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Fluvial sediment supply and pioneer woody seedlings as a control on bar‐surface topography          下载免费PDF全文

Rebecca M. Diehl  Andrew C. Wilcox  John C. Stella  Li Kui  Leonard S. Sklar  Anne Lightbody 《地球表面变化过程与地形》2017,42(5):724-734

Plants influence river channel topography, but our understanding of the interaction among plants, flow, and sediment is limited, especially when sediment supply is variable. Using laboratory experiments in a recirculating flume with live seedlings in a mobile sand bed, we demonstrate how varying the balance between sediment supply and transport capacity shifts the relationship between plants and bar‐surface topography. Each experimental trial contrasted two sediment conditions, in which initially supply was maintained in equilibrium with transport via sediment recirculation, followed by sediment deficit, in which transport capacity exceeded supply, which was set to zero. For both sediment balances, the topographic response was sensitive to plant size, with larger plants inducing greater aggradation relative to a baseline condition. During sediment equilibrium, the positive relationship between plant size and topographic change also depended on species morphology (multi‐stemmed shrubs versus single‐stemmed plants). Plant morphology effects disappeared when the sediment balance shifted to a deficit, but the presence of plants had a greater impact on the magnitude of change compared to the topographic response under sediment equilibrium. Our results suggest that the interactions among sediment supply, plants, and topography may be strongest on rivers with a balance in sediment supply and transport capacity. Because of the large variability in fluvial sediment supply resulting from natural and anthropogenic influences, these interactions will differ spatially (e.g. longitudinally through a watershed) and at different temporal scales, from single flood events to longer time periods. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Debris flows in the Andean ranges of central Chile and Argentina triggered by 2013 summer storms: characteristics and consequences   总被引：3，自引：2，他引：1  

Sergio A. Sepúlveda  Stella M. Moreiras  Marisol Lara  Alejandro Alfaro 《Landslides》2015,12(1):115-133

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Combination of different space-geodetic observations for regional ionosphere modeling   总被引：2，自引：1，他引：1  

Denise Dettmering  Michael Schmidt  Robert Heinkelmann  Manuela Seitz 《Journal of Geodesy》2011,85(12):989-998

Most of the space-geodetic observation techniques can be used for modeling the distribution of free electrons in the Earth’s ionosphere. By combining different techniques one can take advantage of their different spatial and temporal distributions as well as their different observation characteristics and sensitivities concerning ionospheric parameter estimation. The present publication introduces a procedure for multi-dimensional ionospheric modeling. The model consists of a given reference part and an unknown correction part expanded in terms of B-spline functions. This approach is used to compute regional models of Vertical Total Electron Content (VTEC) based on the International Reference Ionosphere (IRI 2007) and GPS observations from terrestrial Global Navigation Satellite System (GNSS) reference stations, radio occultation data from Low Earth Orbiters (LEOs), dual-frequency radar altimetry measurements, and data obtained by Very Long Baseline Interferometry (VLBI). The approach overcomes deficiencies in the climatological IRI model and reaches the same level of accuracy than GNSS-based VTEC maps from IGS. In areas without GNSS observations (e.g., over the oceans) radio occultations and altimetry provide valuable measurements and further improve the VTEC maps. Moreover, the approach supplies information on the offsets between different observation techniques as well as on their different sensitivity for ionosphere modeling. Altogether, the present procedure helps to derive improved ionospheric corrections (e.g., for one-frequency radar altimeters) and at the same time it improves our knowledge on the Earth’s ionosphere.  相似文献   

Estimating resource costs of compliance with EU WFD ecological status requirements at the river basin scale     

Niels Riegels  Roar Jensen  Lisa Bensasson  Stella Banou  Flemming Møller  Peter Bauer-Gottwein 《Journal of Hydrology》2011,396(3-4):197-214

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Assessing the economic value of vernacular architecture of mountain regions using contingent valuation     

Stella GIANNAKOPOULOU  Dimitris DAMIGOS  Dimitris KALIAMPAKOS 《山地科学学报》2011,8(5):629-640

Human pressure on mountain resources poses certain threats to their natural and man-made environment. Although there are many parameters involved, one of the driving forces behind this situation is the emphasis given so far only to the market value of mountain goods and services, ignoring the true social and environmental costs of using mountain resources. Towards this direction, the use of non-market valuation techniques could prove to be beneficial. Bearing in mind the above remarks, the paper presents an application of the Contingent Valuation Method, which aims at estimating the monetary value of a mountain settlement’s vernacular architecture, namely Metsovo. For this purpose, the survey focuses on Metsovo visitors’ willingness to pay a single annual voluntary contribution to an institution that would be founded in order to undertake all necessary actions required to preserve the town’s traditional character. The results are very promising and indicate that vernacular architecture holds a significant economic value that could justify the implementation of appropriate policies towards the protection of vernacular settlements in mountain areas.  相似文献   

Search for radio pulsations in four Anomalous X-ray Pulsars and discovery of two new pulsars   总被引：1，自引：0，他引：1  

M. Burgay  N. Rea  G. L. Israel  A. Possenti  L. Burderi  T. Di Salvo  N. D'Amico  L. Stella 《Monthly notices of the Royal Astronomical Society》2006,372(1):410-416

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Long term spectral variability in the soft gamma-ray repeater SGR 1900+14     

Andrea Tiengo  Paolo Esposito  Sandro Mereghetti  Lara Sidoli  Diego Götz  Marco Feroci  Roberto Turolla  Silvia Zane  Gian Luca Israel  Luigi Stella  Peter Woods 《Astrophysics and Space Science》2007,308(1-4):33-37

We present a systematic analysis of all the BeppoSAX data of SGR1900+14. The observations spanning five years show that the source was brighter than usual on two occasions: ～20 days after the August 1998 giant flare and during the 10⁵?s long X-ray afterglow following the April 2001 intermediate flare. In the latter case, we explore the possibility of describing the observed short term spectral evolution only with a change of the temperature of the blackbody component. In the only BeppoSAX observation performed before the giant flare, the spectrum of the SGR1900+14 persistent emission was significantly harder and detected also above 10 keV with the PDS instrument. In the last BeppoSAX observation (April 2002) the flux was at least a factor 1.2 below the historical level, suggesting that the source was entering a quiescent period.  相似文献