Search results for "Spatial"
showing 10 items of 2121 documents
Electrical Coupling in Ensembles of Nonexcitable Cells: Modeling the Spatial Map of Single Cell Potentials
2015
We analyze the coupling of model nonexcitable (non-neural) cells assuming that the cell membrane potential is the basic individual property. We obtain this potential on the basis of the inward and outward rectifying voltage-gated channels characteristic of cell membranes. We concentrate on the electrical coupling of a cell ensemble rather than on the biochemical and mechanical characteristics of the individual cells, obtain the map of single cell potentials using simple assumptions, and suggest procedures to collectively modify this spatial map. The response of the cell ensemble to an external perturbation and the consequences of cell isolation, heterogeneity, and ensemble size are also ana…
A mesoscopic approach to point-defect clustering in solids during irradiation
1993
Accumulation of point defects in solids during irradiation is often accompanied by self-organization processes which lead to point-defect clustering and thus to the formation of a spatially inhomogeneous defect structure. Within the framework of a mesoscopic phenomenological approach, the conditions for clustering of mobile point defects caused by their elastic interactions are studied. It is shown that differences between the elastic interaction of similar and that of dissimilar defects may lead to such clustering. Further, it is shown that the presence of impurities acting as traps for interstitials may promote the clustering process. The conditions for spatial clustering are studied for …
Zooplankton biodiversity and community structure vary along spatiotemporal environmental gradients in restored peridunal ponds
2015
<p>Zooplankton assemblages in neighboring ponds can show important spatial and temporal heterogeneity. Disentangling the influence of regional versus local factors, and of deterministic versus stochastic processes has been recently highlighted in the context of the metacommunity theory. In this study, we determined patterns of temporal and spatial variation in zooplankton diversity along one hydrological year in restored ponds of different hydroperiod and age. The following hypotheses regarding the assembling of species over time were tested: i) dispersal is not limited in our study system due to its small area and high exposure to dispersal vectors; ii) community dissimilarity among …
On How to Build SDI Using Social Networking Principles in the Scope of Spatial Planning and Vocational Education
2011
Several ways how to build a spatial data infrastructure usable for spatial planning domain exist. It must be said that today the area of spatial planning is under the influence of the European INSPIRE directive. It is necessary to spread an awareness about how to build this infrastructure in terms of INSPIRE. The article describes the current ways how to build the spatial data infrastructure. Furthermore, a new approach - GeoPortal4everybody, based also on using of social networking principles is proposed. Next, the paper presents using of GeoPortal4everybody concept as a part of technological framework for vocational education partially developed in the SDI-EDU project. This project aims o…
A Dutch contribution to early interpretations of Meteor Crater, Arizona, USA – Marten Edsge Mulder’s ignored 1911 paper
2018
Abstract Following the first scientific descriptions in the late nineteenth century, the origin of the curious structure currently known as Meteor Crater (or Barringer Crater) in Arizona (USA) remained controversial until well into the twentieth century. Within the context of commercial mining, Daniel Moreau Barringer’s view that it recorded a substratum-penetrative meteorite impact (with the cosmic body still preserved) was commonly discarded. Marten Edsge Mulder (1847–1928), Dutch professor of medicine, found fault with Barringer’s non-explosive model. In 1911, Mulder advanced, in an ignored paper written in Dutch, a novel model of an explosive meteorite (‘meteor’ in Mulder’s terminology)…
Comparison of evapotranspiration estimates by NOAA-AVHRR images and aircraft flux measurements in a semiarid region of Spain.
1998
Abstract This paper is intended to show how to aggregate two different remote-sensing techniques carried out in the framework of the European-Union funded project EFEDA (European Field Experiment in a Desertification-threatened Area). One of these is based on satellite measurements, and the other on aircraft flux measurements. The aim of putting together both methodologies was to determine regional evapotranspiration as a major component of the water balance in Castilla-La Mancha, a semiarid region in southeast Spain. The basis for the satellite approach is using temperature information collected by the Advanced Very High-Resolution Radio- meter (AVHRR) sensor on board the National Oceanic …
HAPEX-Sahel
1997
The variation in evaporative fraction and actual evaporation is examined for three sample days in the HAPEX-Sahel Intensive Observation Period (IOP), including data from all the vegetation types and sites. The trends in evaporative fraction over the IOP are also presented for eight sites. The high rate of evaporation from bare soil in the days following rainfall produces a variability in evaporation which makes differences between sites difficult to interpret on a day-to-day basis, but over the whole IOP it is shown that the millet uses a smaller proportion of the available energy for evaporation than the tiger bush or fallow savannah. The combined effect of differences in the total energy …
About the Problem of Scaling from Ground Measurements to Low Resolution Satellite Data
2005
Only satellite data can really produce "global" datasets, and the role of satellite data in the study of global processes is really essential, but ground measurements are also needed to calibrate satellite data and to validate models routinely working with satellite data inputs. The problem of comparing ground measurements with the measurements made by a satellite, particularly in the case of low resolution data (as NOAA AVHRR) imply the consideration of the problem of scaling, both in the case of particular measurements and in the case of mathematical models relating such measurements. Within the context of the EFEDA field experiment, the problem of scaling from ground measurements to low …
Uncontrolled methane emissions from a MSW landfill surface: Influence of landfill features and side slopes
2013
Sanitary landfills for Municipal Solid Waste (MSW) disposal have been identified as one of the most important anthropogenic sources of methane (CH4) emissions; in order to minimize its negative effects on the environment, landfill gas (LFG) recovery is a suitable tool to control CH4 emissions from a landfill site; further, the measurement of CH4 emissions can represent a good way to evaluate the effectiveness of LFG recovering systems. In general, LFG will escape through any faults in the landfill capping or in the LFG collection system. Indeed, some areas of the capping can be more permeable than others (e.g. portions of a side slope), especially when considering a temporarily capped zone …
On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crys…
2021
Hybrid perovskite materials are one of the most promising candidates for optoelectronic applications, e.g., solar cells and LEDs, which can be produced at low cost compared to established materials. Although this field of research has seen a huge upsurge in the past decade, there is a major lack in understanding the underlying processes, such as shape-property relationships and the role of defects. Our aerosol-assisted synthesis pathway offers the possibility to obtain methylammonium lead bromide (MAPbBr3 ) microcrystals from a liquid single source precursor. The differently shaped particles are aligned on several substrates, without using a directing agent or other additives. The obtained …