Complex isotopic-geochemical (Sm-Nd,U-Pb) study of Salma eclogites   总被引：1，自引：0，他引：1  

Skublov  S. G.  Berezin  A. V.  Marin  Yu. B.  Rizvanova  N. G.  Bogomolov  E. S.  Sergeeva  N. A.  Vasil’eva  I. M.  Guseva  V. F. 《Doklady Earth Sciences》2010,434(2):1396-1400

Doklady Earth Sciences -  相似文献   

Mainstem and Backwater Fish Assemblages in the Tidal Caloosahatchee River: Implications for Freshwater Inflow Studies     

Philip W. Stevens  Marin F. D. Greenwood  Charles F. Idelberger  David A. Blewett 《Estuaries and Coasts》2010,33(5):1216-1224

Research strategies for investigating the freshwater-inflow requirements of estuarine fishes often integrate life-history information and correlative analyses of inflow and fish abundance. In tidal rivers, however, some fish have affinities for embayments, oxbows, and smaller tributaries, often referred to collectively as river “backwaters”. The objective of this study was to determine whether freshwater and estuarine fish assemblages differed between backwaters and the mainstem of the tidal Caloosahatchee River, a highly managed river system located in an urban setting in southwest Florida. Nonmetric multidimensional scaling of 21.3-m seine data revealed that fish assemblages did indeed differ between the backwater and mainstem habitats in each of three river sections. Univariate analyses identified species that differed in abundance between the habitats, which included ecologically and economically important fishes in the region. For example, striped mullet Mugil cephalus and pinfish Lagodon rhomboides were more abundant along the river's mainstem; common snook Centropomus undecimalis and bluegill Lepomis macrochirus were more abundant in the river's backwaters. For those species that were more abundant along the mainstem of the river or showed no difference, studies that measure changes in the distribution and abundance of these species with varying inflow along the mainstem of the river are justified. However, for species that were more abundant in backwater areas, geomorphological features should be considered in the design of studies that assess factors affecting fish use.  相似文献   

Vulnerability and adaptation in a dryland community of the Elqui Valley, Chile   总被引：1，自引：0，他引：1  

Gwendolynne Young  Humberto Zavala  Johanna Wandel  Barry Smit  Sonia Salas  Elizabeth Jimenez  Melitta Fiebig  Roxana Espinoza  Harry Diaz  Jorge Cepeda 《Climatic change》2010,98(1-2):245-276

Livelihoods in drylands are already challenged by the demands of climate variability, and climate change is expected to have further implications for water resource availability in these regions. This paper characterizes the vulnerability of an irrigation-dependent agricultural community located in the Elqui River Basin of Northern Chile to water and climate-related conditions in light of climate change. The paper documents the exposures and sensitivities faced by the community in light of current water shortages, and identifies their ability to manage these exposures under a changing climate. The IPCC identifies potentially increased aridity in this region with climate change; furthermore, the Elqui River is fed by snowmelt and glaciers, and its flows will be affected by a warming climate. Community vulnerability occurs within a broader physical, economic, political and social context, and vulnerability in the community varies amongst occupations, resource uses and accessibility to water resources, making some more susceptible to changing conditions in the future. This case study highlights the need for adaptation to current land and water management practices to maintain livelihoods in the face of changes many people are not expecting.  相似文献   

Influences of upwelling and downwelling winds on red tide bloom dynamics in Monterey Bay,California     

John P. Ryan  Andrew M. Fischer  Raphael M. Kudela  James F.R. Gower  Stephanie A. King  Roman Marin  Francisco P. Chavez 《Continental Shelf Research》2009,29(5-6):785-795

It has recently been shown that inner shelf waters of NE Monterey Bay, California function as an “extreme bloom incubator”, frequently developing dense “red tide” blooms that can rapidly spread. Located within the California Current upwelling system, this open bay is strongly influenced by oceanographic dynamics resulting from cycles of upwelling favorable winds and their relaxation and/or reversal. Different wind forcing causes influx of different water types that originate outside the bay: cold nutrient-rich waters during upwelling and warm nutrient-poor waters during relaxation. In this study, we examine how the bay's bloom incubation area can interact with highly variable circulation to cause red tide spreading, dispersal and retention. This examination of processes is supported by satellite, airborne and in situ observations of a major dinoflagellate bloom during August and September of 2004. Remote sensing of high spatial, temporal and spectral resolution shows that the bloom originated in the NE bay, where it was highly concentrated in a narrow band along a thermal front. Upwelling circulation rapidly spread part of the bloom, mixing cool waters of an upwelling filament with warm bloom source waters as they spread. Vertical migration of the dinoflagellate populations was mapped by autonomous underwater vehicle surveys through the spreading bloom. Following bloom expansion, a two-day wind reversal forced intrusion of warm offshore waters that dispersed much of the bloom. Upwelling winds then resumed, and the bloom was further dispersed by an influx of cold water. Throughout these oceanographic responses to changing winds, an intense bloom persisted in sheltered waters of the NE bay, where extreme blooms are most frequent and intense. Microscopic examination of surface phytoplankton samples from the central bay showed that spreading of the bloom from the NE bay and mixing with regional water masses resulted in significantly increased abundance of dinoflagellates and decreased abundance of diatoms. Similar dinoflagellate bloom incubation sites are indicated in other areas of the California Current system and other coastal upwelling systems. Through frequent bloom development and along-coast transports, relatively small incubation sites may significantly influence larger regions of the coastal marine ecosystems in which they reside.  相似文献   

Unbiased sampling from a falling stream of particulate material     

Pierre GY  Lucien Marin 《International Journal of Mineral Processing》1978,5(3):297-315

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Physically-based landslide susceptibility analysis using Monte Carlo simulation in a tropical mountain basin     

Roberto J. Marin  Álvaro J. Mattos 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2020,14(3):192-205

ABSTRACT

Physically-based distributed models are implemented for landslide susceptibility and hazard assessment around the world. Probabilistic methodologies are considered appropriate to study and quantify the uncertainties derived from the input parameters of these models. In this paper, three sets of Monte Carlo simulations, each one with 10,000 iterations, were applied for a slope stability analysis in a small basin of Envigado (Colombia), using the TRIGRS model, to characterise the uncertainty in the landslide assessment. Different parameters to determine the minimum number of realizations required to ensure a small variation in the failure probability were proposed and analyzed. The quality of the landslide susceptibility assessment was studied. Unexpected and probably erroneous results that may be common in the maps generated using this and other similar methodologies were identified and explained. Additionally, the distribution of the factor of safety was calculated for different grid cells of the basin, showing that the probability density function with the best adjustment to the frequency histogram of the factor of safety can vary between grid cells. The assumption of a normal distribution for the factor of safety would be inappropriate and would lead to miscalculations in this case study.  相似文献   

Water and the rural poor in Latin America: The case of Tlamacazapa, Guerrero, Mexico     

Susan E. Smith  Luis E. Marin 《Hydrogeology Journal》2005,13(1):346-349

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Rural settlements in transition – agricultural and countryside crisis in the Central-Eastern Europe     

Violette Rey  Marin Bachvarov 《GeoJournal》1998,44(4):345-353

The paper presents a synthesis of French and Bulgarian researches on the transition in villages in Central Eastern Europe. The main points focus on three questions, the rural unemployment and the crisis of small towns, the demographical deterioration, the new relations between villages and towns. A generalization of the rural central places' visual change and metaphors is proposed, completed by a typology of rural settlements. The question of the rural administrative divisions is discussed, with its implication for the future. As a whole the paper gives a contribution to the problematic of the likely development in the rural evolution pattern throughout Europe. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Hydrogeological Investigations in Northwestern Yucatan, Mexico, Using Resistivity Surveys   总被引：4，自引：0，他引：4  

Birgit Steinich  Luis E. Marin 《Ground water》1996,34(4):640-646

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Determination of Boron Concentration in Geochemical Reference Materials Extracted by Pyrohydrolysis and Measured by ICP‐MS          下载免费PDF全文

Agnès Michel  Johanna Noireaux  Mickaël Tharaud 《Geostandards and Geoanalytical Research》2015,39(4):489-495

This article presents new boron concentrations for nine geochemical reference materials (GS‐N, FK‐N, GL‐O, BX‐N, DT‐N, AN‐G, GH, Mica‐Fe, Mica‐Mg). After extraction by a modified pyrohydrolysis technique, boron concentrations were measured by ICP‐MS. The blank levels for the whole procedure were 0.091 ± 0.020 ng ml^?1 or 14 ± 5 ng of boron in total. The method was first validated by measuring nine reference materials with known boron concentrations. The determined boron concentrations are all within the range of recommended or published values, which means that the yields were 100%, and show precisions below 10% for samples containing over 2 μg g^?1 of boron.  相似文献