Orientation information in wayfinding instructions: evidences from human verbal and visual instructions     

Vanessa Joy A. Anacta  Angela Schwering  Rui Li  Stefan Muenzer 《GeoJournal》2017,82(3):567-583

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The role of long‐term human impact on avulsion and fan development          下载免费PDF全文

Vanessa Mary An Heyvaert  Jan Walstra 《地球表面变化过程与地形》2016,41(14):2137-2152

This study aims to understand (mainly qualitatively) the long‐term role of human impact on avulsion processes and the development of fluvial (mega‐) fans in semi‐arid environments. In this paper we refer to human impact as the direct influences of actions on the river's hydraulics (i.e. flow regulation, flow diversion and channel engineering). In five case‐studies drawn from the Khuzestan plains in southwest Iran we have analysed the setup and triggering conditions of specific avulsions that occurred in the past (timescale of millennia) and identified the role of human interference in their causation. Our analysis is based on the integration of historical, archaeological, geomorphological and geological data. Through this study we demonstrate that avulsions in the Khuzestan plains are the result of long‐term and complex interplay between multiple human‐induced and natural causes. In similar ways human‐induced actions may play important roles during different phases of avulsion development. The ‘success‘ of an avulsion in the post‐triggering phase may be defined by human‐induced setup causes as well as morphodynamic processes. We suggest that present‐day flood events may be partly inherited from long‐term human alterations of the natural processes. These finding could have implications for any fluvial system (e.g. distributive fluvial systems, deltas) where avulsion plays a major role in their development and research tends to emphasize on natural mechanisms. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

User expectations for multibeam echo sounders backscatter strength data-looking back into the future     

Vanessa Lucieer  Marc Roche  Koen Degrendele  Mashkoor Malik  Margaret Dolan  Geoffroy Lamarche 《Marine Geophysical Researches》2018,39(1-2):23-40

With the ability of multibeam echo sounders (MBES) to measure backscatter strength (BS) as a function of true angle of insonification across the seafloor, came a new recognition of the potential of backscatter measurements to remotely characterize the properties of the seafloor. Advances in transducer design, digital electronics, signal processing capabilities, navigation, and graphic display devices, have improved the resolution and particularly the dynamic range available to sonar and processing software manufacturers. Alongside these improvements the expectations of what the data can deliver has also grown. In this paper, we identify these user-expectations and explore how MBES backscatter is utilized by different communities involved in marine seabed research at present, and the aspirations that these communities have for the data in the future. The results presented here are based on a user survey conducted by the GeoHab (Marine Geological and Biological Habitat Mapping) association. This paper summarises the different processing procedures employed to extract useful information from MBES backscatter data and the various intentions for which the user community collect the data. We show how a range of backscatter output products are generated from the different processing procedures, and how these results are taken up by different scientific disciplines, and also identify common constraints in handling MBES BS data. Finally, we outline our expectations for the future of this unique and important data source for seafloor mapping and characterisation.  相似文献   

Geochemistry and origins of the annagh division of the precambrian erris complex,N.W. county Mayo,Ireland     

J.A. Winchester  M.D. Max 《Precambrian Research》1984,25(4):397-414

A geochemical study of 29 acid gneisses from the Annagh Division of the Erris Complex has shown that all lithologies are chemically distinct and that further distinction can be made between different areas. The acid and intermediate gneisses, which in the field have been regarded as orthogneisses associated with widespread metasomatism, have orthogneiss chemistry and show the effects of considerable local metasomatism. Isotopic age dating records that the latest major pre-Caledonian event in the Annagh Gneiss is of Grenvillian age. The Annagh Division gneiss differs chemically from Laxford gneiss but is similar to reworked Lewisian inliers seen in the N.W. Highlands of Scotland.All analysed basic rocks fall into three categories: early basic and ultrabasic pods and metadolerite dykes. All originated as minor intrusives of tholeiitic affinities.  相似文献   

Enriched asthenosphere melting beneath the nascent North African margin: trace element and Nd isotope evidence in middle–late Triassic alkali basalts from central Sicily (Italy)     

Rosolino Cirrincione  Patrizia Fiannacca  Michele Lustrino  Vanessa Romano  Annunziata Tranchina  Igor M. Villa 《International Journal of Earth Sciences》2016,105(2):595-609

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Submerged vegetation complexity modifies benthic infauna communities: the hidden role of the belowground system          下载免费PDF全文

Vanessa González‐Ortiz  Luis Gonzalo Egea  Rocio Jiménez‐Ramos  Francisco Moreno‐Marín  José Lucas Pérez‐Lloréns  Tjeerd Bouma  Fernando Brun 《Marine Ecology》2016,37(3):543-552

Marine plants provide a variety of functions with high economic and ecological values in ecosystems. The above‐ (AG) and below‐ground (BG) systems increase the structural complexity of plants, which also enhance faunal abundance and diversity. The ecological role of the AG compartment in structuring inter‐tidal macrobenthic communities has been widely studied; however, this is not the case for the BG compartment. This study addressed the effects of variation in vegetation complexity (in both AG and BG systems) on associated macrobenthic infauna with respect to abundance, species richness, composition, weight and body type. To achieve this aim, a field experiment using artificial vegetation mimics was carried out using replicated treatments with different AG‐BG complexity ratios. We found a significant increase in the density and the number of taxa of macrobenthic infaunal species in plots with vegetation mimics compared with unvegetated areas, regardless of either AG or BG complexity. This effect was found even when AG parts were not present (i.e. when only BG parts were used). Furthermore, a positive relationship between structural complexity and diversity was recorded. Variation in one or both plant compartments was strongly related to diversity changes in the associated macrobenthic infauna. In conclusion, our experimental set‐up provides the first evidence that the BG compartment is at least as important as the AG compartment in controlling diversity in inter‐tidal vegetated areas because it was able to strongly affect community structure even when the AG system was totally absent.  相似文献   

Depuration dynamics of oysters (Crassostrea gigas) artificially contaminated by Salmonella enterica serovar Typhimurium     

de Abreu Corrêa A  Albarnaz JD  Moresco V  Poli CR  Teixeira AL  Oliveira Simões CM  Monte Barardi CR 《Marine environmental research》2007,63(5):479-489

The State of Santa Catarina produces the greatest quantity of edible mollusks in Brazil. To guarantee sanitary qualify, mollusk cultures should be monitored for contamination by pathogenic microorganisms. A self-purification or "depuration" system that eliminates Salmonella enterica serovar Typhimurium contamination from oysters has been developed and evaluated. The depuration process occurred within a closed system, in which 1000 L of water was recirculated for 24 h. The water was sterilized with ultraviolet (UV) light, chlorine, or both together. Oysters (Crassostrea gigas) artificially contaminated with S. typhimurium were harvested every 6 h. Samples of oyster tissue were excised and both the presence and numbers of bacteria were determined. Combined UV light and chlorine treatments resulted in total elimination of bacteria within 12 h. Polymerase chain reaction detected bacteria in water exposed to the three treatments. This pioneering study is the first of its kind in Brazil and represents a major contribution to commercial mollusk culture in this country.  相似文献   

Geomorphology: the mechanics and chemistry of landscapes – By Robert S. Anderson and Suzanne P. Anderson     

Vanessa Wong 《New Zealand geographer》2012,68(1):74-75

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The Turbulent Lagrangian Time Scale in Forest Canopies Constrained by Fluxes,Concentrations and Source Distributions   总被引：1，自引：1，他引：0  

Vanessa Haverd  Ray Leuning  David Griffith  Eva van Gorsel  Matthias Cuntz 《Boundary-Layer Meteorology》2009,130(2):209-228

One-dimensional Lagrangian dispersion models, frequently used to relate in-canopy source/sink distributions of energy, water and trace gases to vertical concentration profiles, require estimates of the standard deviation of the vertical wind speed, which can be measured, and the Lagrangian time scale, T _L , which cannot. In this work we use non-linear parameter estimation to determine the vertical profile of the Lagrangian time scale that simultaneously optimises agreement between modelled and measured vertical profiles of temperature, water vapour and carbon dioxide concentrations within a 40-m tall temperate Eucalyptus forest in south-eastern Australia. Modelled temperature and concentration profiles are generated using Lagrangian dispersion theory combined with source/sink distributions of sensible heat, water vapour and CO₂. These distributions are derived from a multilayer Soil-Vegetation-Atmospheric-Transfer model subject to multiple constraints: (1) daytime eddy flux measurements of sensible heat, latent heat, and CO₂ above the canopy, (2) in-canopy lidar measurements of leaf area density distribution, and (3) chamber measurements of CO₂ ground fluxes. The resulting estimate of Lagrangian time scale within the canopy under near-neutral conditions is about 1.7 times higher than previous estimates and decreases towards zero at the ground. It represents an advance over previous estimates of T _L , which are largely unconstrained by measurements.  相似文献   

Extensions to the Lewisian Inlier of Fannich Forest,Ross-shire     

J.A. Winchester 《Proceedings of the Geologists' Association. Geologists' Association》1973,84(3):273-282

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