3,859 research outputs found
Indagine geoelettrica per la valutazione dell'intrusione salina negli acquiferi costieri del comprensorio meridionale veneziano
Riassunto
Attraverso l’indagine geoelettrica è stata eseguita una prima valutazione dell’estensione dell’intrusione salina marina e lagunare nel settore meridionale del comprensorio veneziano.
Nel settore costiero, caratterizzato da dune e cordoni litoranei, è presente una falda freatica con acqua “dolce” fino ad una profondità di anche una decina di metri e l’intrusione salina coinvolge i terreni sottostanti fino ad oltre 70 metri.
Nell’entroterra, la soggiacenza del territorio rispetto al livello marino, i pompaggi con idrovore e la rete idrografica pensile in comunicazione col mare sono fattori che riducono a pochi metri, ed in alcune zone annullano, lo spessore della falda dolce superficiale e consentono al cuneo salino di raggiungere la base dei terreni coltivati.
Abstract
A preliminary evaluation of the salt water intrusion in coastal aquifers of the southern Venetian region, is here made using geoelectical investigation.
The results of the analyses show that the two dimensional extent of the saline contamination is mainly related to the geomorphology of this area.
In the littoral sector, characterized by a mean ground elevation of two meters above mean sea level (sand dunes and paleolittoral strips), a phreatic fresh water body is present and salt water contamination involves aquifers and aquitards from 10 to 70 m deep.
In the inland, the ground level is about 2-3 m below mean sea level; the water pumping in the reclaimed lands and the marine water seepage in the rivers during high tides are among the factors that seriously reduce the fresh water body and that allow salt water to contaminate the agricultural soils
Limit cycles in Lienard equations
An analytical estimation of the existence and characteristics of limit cycles in a given planar polynomial vector field represents a significant progress towards the complete answer to the second part of Hilbert’s 16th problem. In a very recent work [1], the second author of this present paper has developed a theory to fulfil this purpose. One major conclusion of the theory is that the number of limit cycles nested around a critical point in a general planar polynomial vector field is bounded by the Hilbert number where n is the order of the vector field. It is well known that linear vector fields have no limit cycles and this, of course agrees with the conclusion. Shi [2] shows that there are maximum three limit cycles nested around a critical point in quadratic vector fields. Again, it is in an agreement with the conclusion. For cubic vector fields results from previous studies [3,4,5] are also in an agreement with the conclusion whilst the result from the work [6] is in a disagreement although there exists some doubt about the result. In this present work, a detailed study is given to the limit cycles in a fifteenth order Liénard equation by using both the theory [1] and numerical simulations to check the validity of the theory. The method of analysis is briefly given in Section 2. An application example and conclusions are presented in Section 3 and 4, respectively
WoodCircus, Underpinning the vital role of the forest-based sector in the Circular Bioeconomy. D2.2 Resource Efficiency, Side Streams and Value Chain Analysis – WP2 Final Report
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Apoferritin nanocage as drug reservoir: is it a reliable drug delivery system?
Apoferritin is a complex protein with a number of possibilities for drug delivery and drug targeting technologies, as it could be considered as the future self-assembling, not-toxic protein drug delivery carrier. Few years ago, this concept was a reality; nowadays, after more than 10 years of research, a clear painting of Apoferritin, loaded with drugs, is lacking, in terms of protocols of formulation, characterization, drug release and application. Therefore, a critical evaluation and overall understanding of Apoferritin is due to speed up the possibilities for its translatability into clinical application
A Self-Replicating Single-Shape Tiling Technique for the Design of Highly Modular Planar Phased Arrays -- The Case of L-Shaped Rep-Tiles
The design of irregular planar phased arrays (PAs) characterized by a
highly-modular architecture is addressed. By exploiting the property of
self-replicating tile shapes, also known as rep-tiles, the arising array
layouts consist of tiles having different sizes, but equal shape, all being
generated by assembling a finite number of smaller and congruent copies of a
single elementary building-block. Towards this end, a deterministic
optimization strategy is used so that the arising rep-tile arrangement of the
planar PA is an optimal trade-off between complexity, costs, and fitting of
user-defined requirements on the radiated power pattern, while guaranteeing the
complete overlay of the array aperture. As a representative instance, such a
synthesis method is applied to tile rectangular apertures with L-shaped tromino
tiles. A set of representative results, concerned with ideal and real antenna
models, as well, is reported for validation purposes, but also to point out the
possibility/effectiveness of the proposed approach, unlike state-of-the-art
tiling techniques, to reliably handle large-size array apertures.Comment: 56 pages, 22 figure
Time-Dependent Current-Density-Functional Theory of Spin-Charge Separation and Spin Drag in One-Dimensional Ultracold Fermi Gases
URL:http://link.aps.org/doi/10.1103/PhysRevLett.101.206402
DOI:10.1103/PhysRevLett.101.206402Motivated by the large interest in the nonequilibrium dynamics of low-dimensional quantum many-body systems, we present a fully microscopic theoretical and numerical study of the charge and spin dynamics in a one-dimensional ultracold Fermi gas following a quench. Our approach, which is based on time-dependent current-density-functional theory, is applicable well beyond the linear-response regime and produces both spin-charge separation and spin-drag-induced broadening of the spin packets.G. X. was supported by NSF of China under Grant
No. 10704066 and by DOE Grant No. DE-FG02-
05ER46203. G.V. was supported by NSF Grants
Nos. DMR-031368 and DMR-0705460
Protein cage nanostructure as drug delivery system: magnifying glass on apoferritin
New frontiers in nanomedicine are moving towards the research of new biomaterials. Apoferritin (APO), is a uniform regular self-assemblies nano-sized protein with excellent biocompatibility and a unique structure that affords it the ability to stabilize small active molecules in its inner core. Areas covered: APO can be loaded by applying a passive process (mainly used for ions and metals) or by a unique formulative approach based on disassemby/reassembly process. In this article, we aim to organize the experimental evidence provided by a number of studies on the loading, release and targeting. Attention is initially focused on the most investigated antineoplastic drug and contrast agents up to the most recent application in gene therapy. Expert opinion: Various preclinical studies have demonstrated that APO improved the potency and selectivity of some chemotherapeutics. However, in order to translate the use of APO into therapy, some issues must be solved, especially regarding the reproducibility of the loading protocol used, the optimization of nanocarrier characterization, detailed understanding of the final structure of loaded APO, and the real mechanism and timing of drug release
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