Search results for "Spatial Distribution"
showing 10 items of 180 documents
Characterization of spatial porosity and mineral distribution of crystalline rock using X-ray micro computed tomography, C-14-PMMA autoradiography an…
2019
The spatial porosity and mineral distribution of geological materials strongly affects transport processes in them. X-ray micro computed tomography (X-mu CT) has proven to be a powerful tool for characterizing the spatial mineral distribution of geological samples in 3-D. However, limitations in resolution prevent an accurate characterization of pore space especially for tight crystalline rock samples and 2-D methods such as C-14-polymethylmethacrylate (C-14-PMMA) autoradiography and scanning electron microscopy (SEM) are needed. The spatial porosity and mineral distributions of tight crystalline rock samples from Aspo, Sweden, and Olkiluoto, Finland, were studied here. The X-mu CT were use…
Seed dispersal, braeding system, tree density and the spatial pattern of trees – a simulation approach
2002
Summary Tropical tree populations with low densities and with clumped spatial distributions are at risk in the face of fragmentation. It is therefore important to understand factors driving spatial patterns of tree populations. An important set of factors which may influence the spatial pattern of plants, could be the spatial distribution of possible seed sources such as the breeding system (monoecious, dioecious), tree density and the spatial pattern of the parent population. Another set of important factors might be dispersal of seeds away from the parent plants characterised by the mean dispersal distance and by the distribution of dispersal distances (either negative exponential or logn…
Foraging site fidelity shapes the spatial organisation of a population of female western barbastelle bats
2009
Abstract Information about the spatial distribution of individual foraging habitats, which determines the space required by a population to be viable, is vitally important for the conservation of bats. Detailed knowledge of this kind is crucial for the design of nature reserves and management plans. Recent field studies that examined habitat use and home range distribution of bats largely ignored factors like traditional range use vs. intra- and interspecific competition, which may be responsible for the spatial organisation of a population home range. We investigated the home range sizes and distribution of a maternity colony of the western barbastelle bat via radio telemetry in four conse…
Diel variability in counts of reef fishes and its implications for monitoring
2006
Studies of reef fish assemblages in space rarely consider the effects of temporal variability on spatial comparisons, and when they do, usually examine timescales of months to years. The nature of fish monitoring surveys is such that particular locations may be surveyed at one time of day, and surveys designed to establish the degree of spatial variability in assemblages may be confounded if the order of sampling within treatments is not randomised with respect to time of day. In this study, we tested the degree of temporal variability in temperate reef fish counts at the same sites in New Zealand and Italy, within and between days. Repeated counts separated by months returned quite differe…
Application and evaluation of biomagnetic and biochemical monitoring of the dispersion and deposition of volcanically-derived particles at Mt. Etna, …
2010
article i nfo Article history: Received 6 August 2009 Accepted 4 January 2010 Available online xxxx Biomagnetic monitoring, using tree leaves as passive surfaces for particle collection, has been shown to be a promising technique for assessing the dispersion and deposition of particles in the context of anthropogenic pollution. By comparing leaves' magnetic properties with trace metal levels measured in the leaves, we here assess the utility of the biomagnetic technique as a sensitive, fast and inexpensive method for assessment of volcanic plume deposition. Samples of sweet chestnut leaves (Castanea sativa) were collected from the area surrounding Mt. Etna volcano in Sicily during the 2008 …
Deglaciation history of Latvia
2004
This chapter discusses the deglaciation history of Latvia. The earliest deglaciation schemes of Latvia were based entirely on morphological features. The spatial distribution of glacial landforms, with crests transverse to glacier movement combined with radiocarbon dates and biostratigraphical evidence, have provided the principal data for the reconstruction of the deglaciation process from the mid-1960s until the present. A deglaciation history should be based on multiple criteria. Attention should be paid to the identification of ice-marginal formations, and complex studies are also needed, including the investigation of the spatial distribution and internal composition of subglacial land…
Contrasting textural record of two distinct metamorphic events of similar P-T conditions and different durations
2005
A structural, metamorphic and geochronological study of the StareMesto belt implies the existence of two distinct metamorphic events of similar peak P-T conditions (700-800 � C, 8-10 kbar) during the Cambro-Ordovician and the Carboniferous tectonometamorphic events. The hypothesis of two distinct periods of metamorphism was suggested on the basis of structural discordance between an undoubtedly Carboniferous granodiorite sill intrusion and earlier Cambro-Ordovician fabrics of a banded amphibolite complex. The analysis of crystal size distribution (CSD) shows high nucleation density (N0) and low average growth rate (Gt) for Carboniferous mylonitic metagabbros and mylonitic granodiorites. The…
Turismo inbound e ricettività in Sicilia: un’analisi della distribuzione spaziale
2010
In the last few years a significant increase in tourist accommodation has taken place in Sicily, both in hotels and in other hospitality. The increased number of accommodation beds has been encouraged by a multilevel policy of investments – both regional and European – aimed at filling the qualitative and quantitative gap penalizing Sicily in the field of tourism and accommodation competition. In some way, it may seem that the purpose of improving the accommodation supply in our Island has been obtained: indeed, while in 2000, the year when the previous European planning started, the number of accommodation beds in hotels was, in Sicily, of 4,2% of the national amount, in 2008 the Island ra…
Numerical study of the October 2007 flash flood in the Valencia region (Eastern Spain): the role of orography
2010
Abstract. A torrential rain event took place in the Valencia region in October 2007, mainly affecting coastal areas and nearby mountains in the center-south of the region, in northern Alicante province. More than 400 mm in 24 h were recorded at some stations in these areas, with lower accumulations in the rest of the region where rainfall was less intense. In the first part of this work a description of the meteorological situation is given. The synoptic frame of the event is characterised by an advection of easterly maritime winds across the Western Mediterranean, lasting for at least 48 h, driving moist air towards the Iberian Peninsula eastern coast and the presence of an upper level iso…
Traditional and experimental floating fish aggregating devices in the Gulf of Castellammare (NW Sicily): Results from catches and visual observations
1999
Floating fish aggregating devices (FADs) have long been used to attract fish in NW Sicily since antiquity. Recently, a number of changes have been made to the type of material employed to construct FADs, with the aim of increasing their effectiveness. In this paper we compare the catches made at eight experimental floating FADs (polypropylene ropes frayed at the ends) with those obtained at eight traditional FADs in the Gulf of Castellammare. A total of 672 samples were collected during summer and autumn in 1995 and 1996 at the 16 FADs using a surrounding net. Visual observations of fishes associated with the FADs were also conducted to obtain qualitative information about the spatial distr…