569 research outputs found
Cluster evolution in steady-state two-phase flow in porous media
We report numerical studies of the cluster development of two-phase flow in a
steady-state environment of porous media. This is done by including biperiodic
boundary conditions in a two-dimensional flow simulator. Initial transients of
wetting and non-wetting phases that evolve before steady-state has occurred,
undergo a cross-over where every initial patterns are broken up. For flow
dominated by capillary effects with capillary numbers in order of , we
find that around a critical saturation of non-wetting fluid the non-wetting
clusters of size have a power-law distribution with
the exponent for large clusters. This is a lower value
than the result for ordinary percolation. We also present scaling relation and
time evolution of the structure and global pressure.Comment: 12 pages, 11 figures. Minor corrections. Accepted for publication in
Phys. Rev.
Sickness Behaviors Across Vertebrate Taxa: Proximate and Ultimate Mechanisms
There is nothing like a pandemic to get the world thinking about how infectious diseases affect individual behavior. In this respect, sick animals can behave in ways that are dramatically different from healthy animals: altered social interactions and changes to patterns of eating and drinking are all hallmarks of sickness. As a result, behavioral changes associated with inflammatory responses (i.e. sickness behaviors) have important implications for disease spread by affecting contacts with others and with common resources, including water and/or sleeping sites. In this Review, we summarize the behavioral modifications, including changes to thermoregulatory behaviors, known to occur in vertebrates during infection, with an emphasis on non-mammalian taxa, which have historically received less attention. We then outline and discuss our current understanding of the changes in physiology associated with the production of these behaviors and highlight areas where more research is needed, including an exploration of individual and sex differences in the acute phase response and a greater understanding of the ecophysiological implications of sickness behaviors for disease at the population level
Integrated modelling for assessing the risk of groundwater contaminants to human health and surface water ecosystems
The practical implementation of the European Water Framework Directive has resulted in an increased focus on the groundwater-surface water interaction zone. A gap exists with respect to preliminary assessment methodologies that are capable of evaluating and prioritising point sources of contamination. In particular, adaptive management tools designed to work with sparse data sets from preliminary site assessments are needed which can explicitly link contaminant point sources with groundwater, surface water and ecological impacts. Here, a novel integrated modelling approach was employed for evaluating the impact of a TCE groundwater plume, located in an area with protected drinking water interests, to human health and surface water ecosystems. This is accomplished by coupling the system dynamicsbased decision support system CARO-Plus to the aquatic ecosystem model AQUATOX via an analytical volatilisation model for the stream. The model is tested on a Danish case study involving a 750 m long TCE groundwater plume discharging into a stream. The initial modelling results indicate that TCE contaminant plumes with μgL-1 concentrations entering surface water systems do not pose a significant risk to either human or ecological receptors
Characterizing the role of pesticides impacting surface water ecosystems in multiple stressed environments
Integrated Assessment of the impact of Aqueous Contaminant Stressors on Surface Water Ecosystems
Mass discharge estimation from contaminated sites: Multi-model solutions for assessment of conceptual uncertainty
Can Bayesian Belief Networks help tackling conceptual model uncertainties in contaminated site risk assessment?
Metode til vurdering af konceptuel forståelse og parameter usikkerhed ved beregning af forurenings flux fra forurenede lokaliteter (v2 niveau)
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