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Release Events (release + event)

Distribution by Scientific Domains

Earth and Environmental Science	75%

Selected Abstracts

Post-seismic relaxation following the great 2004 Sumatra-Andaman earthquake on a compressible self-gravitating Earth

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2006
Fred F. Pollitz
SUMMARY The Mw, 9.0 2004 December 26 Sumatra-Andaman and Mw= 8.7 2005 March 28 Nias earthquakes, which collectively ruptured approximately 1800 km of the Andaman and Sunda subduction zones, are expected to be followed by vigorous viscoelastic relaxation involving both the upper and lower mantle. Because of these large spatial dimensions it is desirable to fully account for gravitational coupling effects in the relaxation process. We present a stable method of computing relaxation of a spherically-stratified, compressible and self-gravitating viscoelastic Earth following an impulsive moment release event. The solution is cast in terms of a spherical harmonic expansion of viscoelastic normal modes. For simple layered viscoelastic models, which include a low-viscosity oceanic asthenosphere, we predict substantial post-seismic effects over a region several 100s of km wide surrounding the eastern Indian Ocean. We compare observed GPS time-series from ten regional sites (mostly in Thailand and Indonesia), beginning in 2004 December, with synthetic time-series that include the coseismic and post-seismic effects of the 2004 December 26 and 2005 March 28 earthquakes. A viscosity structure involving a biviscous (Burgers body) rheology in the asthenosphere explains the pattern and amplitude of post-seismic offsets remarkably well. [source]

Classifying tagging experiments for commercial fisheries into three fundamental types based on design, data requirements and estimable population parameters

FISH AND FISHERIES, Issue 2 2010
Tom Polacheck
Abstract Mark,recapture experiments have the potential to provide direct estimates of fundamental parameters required for fishery stock assessment and provision of subsequent management advice in fisheries. The literature on mark,recapture experiments is enormous, with a variety of different experimental designs and estimation models; thus, it can be difficult to grasp the primary features of different approaches, the inter-relationship among them and their potential utility in different situations. Here, we present an overview of the tagging experimental designs that are appropriate for use in commercial fishery situations. We suggest that most mark,recapture experiments in a large-scale fishery context can be classified into one of three basic types , Petersen, tag-attrition or Brownie , based on the fundamental design employed for releases and recaptures. The release and recapture strategy (e.g. the number of release events, whether the size of the sample examined for recaptured tags is known) determines which parameters can be estimated and from where the information for estimating them arises. We conclude that an integrated Brownie and Petersen approach is the most powerful of the different approaches in terms of the range of parameters that can be estimated without underlying assumptions or constraints on parameters. Such an approach can provide direct estimates of fishing mortality, natural mortality and population size, which are the main population dynamics parameters that traditional fishery stock assessments attempt to estimate. [source]

Interstitial cells in the vasculature

JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 2 2005
M. I. Harhun
Abstract Interstitial cells of Cajal are believed to play an important role in gastrointestinal tissues by generating and propagating electrical slow waves to gastrointestinal muscles and/or mediating signals from the enteric nervous system. Recently cells with similar morphological characteristics have been found in the wall of blood vessels such as rabbit portal vein and guinea pig mesenteric artery. These non-contractile cells are characterised by the presence of numerous processes and were easily detected in the wall of the rabbit portal vein by staining with methylene blue or by antibodies to the marker of Interstitial Cells of Cajal c-kit. These vascular cells have been termed "interstitial cells" by analogy with interstitial cells found in the gastrointestinal tract. Freshly dispersed interstitial cells from rabbit portal vein and guinea pig mesenteric artery displayed various Ca2+ -release events from endo/sarcoplasmic reticulum including fast localised Ca2+ transients (Ca2+ sparks) and longer and slower Ca2+ events. Single interstitial cells from the rabbit portal vein, which is a spontaneously active vessel, also demonstrated rhythmical Ca2+ oscillations associated with membrane depolarisations, which suggests that in this vessel interstitial cells may act as pacemakers for smooth muscle cells. The function of interstitial cells from the mesenteric arteries is yet unknown. This article reviews some of the recent findings regarding interstitial cells from blood vessels obtained by our laboratory using electron microscopy, immunohistochemistry, tight-seal patch-clamp recording, and fluorescence confocal imaging techniques. [source]

Disturbance history of a European old-growth mixed-species forest,A spatial dendro-ecological analysis

JOURNAL OF VEGETATION SCIENCE, Issue 5 2005
Bernhard E. Splechtna
Abstract Question: We were interested if and how variation in frequency and/or size of disturbances affect the dynamics of a montane old-growth forest in Central Europe. Location: The forest, co-dominated by Fagus sylvatica, Picea abies and Abies alba, is located in Lower Austria and represents one of the few sizable virgin forests in Central Europe. Methods: We extracted cores from 100 trees using systematic grid sampling (grid cell size 10 m × 10 m) on each of four 1-ha plots distributed across the old-growth remnant of 300 ha. We inferred disturbance events from rapid early growth and release events. For defining release criteria, we applied the boundary line method. We investigated the spatial structure of current age and gap distributions and past disturbance events in grid cells, using a pair density statistic. Results: The disturbance histories indicate decades with peaks and also extended periods without disturbance. Some peaks occurred synchronously at three of the four plots (1910s, 1930s, 1960s and 1980s). Peaks and gaps in the disturbance chronologies widely agreed with peaks and gaps in the age distributions. Most disturbance events during single decades showed a random spatial distribution. Conclusions: There is considerable variation in disturbance frequency and/or severity over time. Most disturbance events will rather thin the stand than clear larger areas at once. Following scattered disturbance two pathways occur: (1) gap expansion leading to creation of larger gaps, and (2) gap closure by lateral encroachment or by subcanopy trees growing into the canopy. [source]