Search results for " delta"
showing 10 items of 154 documents
Recuperación y reintroducción de Marsilea quadrifolia en los arrozales del delta del Ebro (Tarragona, España).
2001
ESTRELLES, E., IBARS, A. M., IRANZO, J. & MORALES, F. 2001. Recuperation and reintroduction of Marsilea quadrifolia in the rice fields of the Ebro's Delta (Tarragona, Spain). Bot. Complutensis 25: 251-259. Marsilea quadrifolia has got to be a extincted species in the Ebro's Delta. In this work the process of recovery of the species is described by sporocarps localization in the soil, germination of the same ones in the laboratory and cultivation in pots of the obtained sporelings, from which we proceeded to the reintroduction of Marsilea quadrifolia in old rice fields inside the land of the Natural Park, as well as the conservation measures ex situ applied on this species that tradition…
Small Mammals in Forests of Romania: Habitat Type Use and Additive Diversity Partitioning
2021
Small mammals are key components of forest ecosystems, playing vital roles for numerous groups of forest organisms: they exert bottom-up and top-down regulatory effects on vertebrate and invertebrate populations, respectively
Uptake prediction of nine heavy metals by Eichhornia crassipes grown in irrigation canals: A biomonitoring approach
2021
The principal objective of this study is to generate mathematical regression equations that facilitate the estimation of the extent to which Eichhornia crassipes (C. Mart.) Solms, water hyacinth, absorbs heavy metals (HMs) into four plant organs (laminae, petioles, roots, and stolons). This study considers the absorption of nine HMs (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), and the E. crassipes evaluated in this study were located in three irrigation canals in the North Nile Delta in Egypt, with sampling being conducted in both monospecific and homogenous E. crassipes. Samples of both E. crassipes and water were collected on a monthly basis during one growing season. Analysis of the water s…
Variation in the stable isotope trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766) from two Mediterranean sites: insights from a g…
2022
A direct consequence of sea warming is the shift in the distribution range of thermo-tolerant species that have the potential to determine novel inter-specific interactions, ultimately altering food web structures and ecosystem processes. In this study, we investigated the trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766), a pelagic predator that has recently expanded its distribution in the Mediterranean basin and for which scant information is available on its functional role in recently-colonised areas. Nitrogen and carbon stable isotopes were determined in muscle tissues of bluefish specimens collected in south-east Italy in the Gulf of Taranto (NW Ionian Sea) and in…
Fast Graph Filters for Decentralized Subspace Projection
2020
A number of inference problems with sensor networks involve projecting a measured signal onto a given subspace. In existing decentralized approaches, sensors communicate with their local neighbors to obtain a sequence of iterates that asymptotically converges to the desired projection. In contrast, the present paper develops methods that produce these projections in a finite and approximately minimal number of iterations. Building upon tools from graph signal processing, the problem is cast as the design of a graph filter which, in turn, is reduced to the design of a suitable graph shift operator. Exploiting the eigenstructure of the projection and shift matrices leads to an objective whose…
Ephaptic coupling of myelinated nerve fibers
2001
Numerical predictions of a simple myelinated nerve fiber model are compared with theoretical results in the continuum and discrete limits, clarifying the nature of the conduction process on an isolated nerve axon. Since myelinated nerve fibers are often arranged in bundles, this model is used to study ephaptic (nonsynaptic) interactions between impulses on parallel fibers, which may play a functional role in neural processing.
Convergence of Boobnov-Galerkin Method Exemplified
2004
In this Note, Boobnov–Galerkin’s method is proved to converge to an exact solution for an applied mechanics problem. We address in detail the interrelation of Boobnov–Galerkin method and the exact solution in the beam deflection problems. Namely, we show the coincidence of these two methods for clamped–clamped boundary conditions, using an alternative set of functions proposed by Filonenko-Borodich.12 Received 25 February 2003; accepted for publication 13 March 2004. Copyright c 2004 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Copies of this paper may be made for personal or internal use, on condition that the copier pay the $10.00 per-copy fee to th…
Coupled Discrete Fractional-Order Logistic Maps
2021
This paper studies a system of coupled discrete fractional-order logistic maps, modeled by Caputo’s delta fractional difference, regarding its numerical integration and chaotic dynamics. Some interesting new dynamical properties and unusual phenomena from this coupled chaotic-map system are revealed. Moreover, the coexistence of attractors, a necessary ingredient of the existence of hidden attractors, is proved and analyzed.
Phylogeny of viroids, viroidlike satellite RNAs, and the viroidlike domain of hepatitis delta virus RNA.
1991
We report a phylogenetic study of viroids, some plant satellite RNAs, and the viroidlike domain of human hepatitis delta virus RNA. Our results support a monophyletic origin of these RNAs and are consistent with the hypothesis that they may be "living fossils" of a precellular RNA world. Moreover, the viroidlike domain of human hepatitis delta virus RNA appears closely related to the viroidlike satellite RNAs of plants, with which it shares some structural and functional properties. On the basis of our phylogenetic analysis, we propose a taxonomic classification of these RNAs.
Una revisió de les crescudes de 1949 a la plana del Xúquer-Túria
2012
El presente trabajo revisa las riadas de 1949, poco antes de que las obras de regulación alteraran el régimen de los ríos principales. Ese año se registraron al menos tres crecidas de diversa magnitud y tipología (invierno, primavera, otoño) en el litoral valenciano. En la primera parte del trabajo se documentan y describen las acontecidas en la llanura aluvial de los ríos Júcar y Turia, principalmente a partir de noticias de prensa. La segunda parte analiza y reconstruye las características hidrológicas de la avenida del 28 de septiembre en el Camp de Turia y L’Horta de València dada su magnitud extraordinaria. También se incide en el carácter vulnerable de la sociedad y en el impacto de a…