5,454 research outputs found

    Evaluating the Differences of Gridding Techniques for Digital Elevation Models Generation and Their Influence on the Modeling of Stony Debris Flows Routing: A Case Study From Rovina di Cancia Basin (North-Eastern Italian Alps)

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    Debris \ufb02ows are among the most hazardous phenomena in mountain areas. To cope with debris \ufb02ow hazard, it is common to delineate the risk-prone areas through routing models. The most important input to debris \ufb02ow routing models are the topographic data, usually in the form of Digital Elevation Models (DEMs). The quality of DEMs depends on the accuracy, density, and spatial distribution of the sampled points; on the characteristics of the surface; and on the applied gridding methodology. Therefore, the choice of the interpolation method affects the realistic representation of the channel and fan morphology, and thus potentially the debris \ufb02ow routing modeling outcomes. In this paper, we initially investigate the performance of common interpolation methods (i.e., linear triangulation, natural neighbor, nearest neighbor, Inverse Distance to a Power, ANUDEM, Radial Basis Functions, and ordinary kriging) in building DEMs with the complex topography of a debris \ufb02ow channel located in the Venetian Dolomites (North-eastern Italian Alps), by using small footprint full- waveform Light Detection And Ranging (LiDAR) data. The investigation is carried out through a combination of statistical analysis of vertical accuracy, algorithm robustness, and spatial clustering of vertical errors, and multi-criteria shape reliability assessment. After that, we examine the in\ufb02uence of the tested interpolation algorithms on the performance of a Geographic Information System (GIS)-based cell model for simulating stony debris \ufb02ows routing. In detail, we investigate both the correlation between the DEMs heights uncertainty resulting from the gridding procedure and that on the corresponding simulated erosion/deposition depths, both the effect of interpolation algorithms on simulated areas, erosion and deposition volumes, solid-liquid discharges, and channel morphology after the event. The comparison among the tested interpolation methods highlights that the ANUDEM and ordinary kriging algorithms are not suitable for building DEMs with complex topography. Conversely, the linear triangulation, the natural neighbor algorithm, and the thin-plate spline plus tension and completely regularized spline functions ensure the best trade-off among accuracy and shape reliability. Anyway, the evaluation of the effects of gridding techniques on debris \ufb02ow routing modeling reveals that the choice of the interpolation algorithm does not signi\ufb01cantly affect the model outcomes

    Nonstandard Methods in Ramsey Theory and Combinatorial Number Theory

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    The goal of this present manuscript is to introduce the reader to the nonstandard method and to provide an overview of its most prominent applications in Ramsey theory and combinatorial number theory.Comment: 126 pages. Comments welcom

    The debris flow occurred at ru secco creek, venetian dolomites, on 4 august 2015: Analysis of the phenomenon, its characteristics and reproduction by models

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    On 4 August 2015, a very high intensity storm, 31.5 mm in 20 min (94.5 mm/h), hit the massif of Mount Antelao on the Venetian Dolomites triggering three stony debris \ufb02ows characterized by high magnitude. Two of them occurred in the historical sites of Rovina di Cancia and Rudan Creek and were stopped by the retaining works upstream the inhabited areas, while the third routed along the Ru Secco Creek and progressively reached the resort area and the village of San Vito di Cadore, causing fatalities and damages. The main triggering factor of the Ru Secco debris \ufb02ow was a large rock collapse on the northern cliffs of Mount Antelao occurred the previous autumn. The fallen debris material deposited on the Vallon d\u2019Antrimoia inclined plateau at the base of the collapsed cliffs and, below it, on the Ru Salvela Creek, covering it from the head to the con\ufb02uence with the Ru Secco Creek. The abundant runoff, caused by the high intensity rainfall on 4 August 2015, entrained about 52,500 m3 of the debris material laying on the Vallon d\u2019Antrimoia forming a debris \ufb02ow surge that hit and eroded the debris deposit covering the downstream Ru Salvela Creek, increasing its volume, about 110,000 m3 of mobilized sediments. This debris \ufb02ow routed downstream the con\ufb02uence, \ufb02ooding the parking of a resort area where three people died, and reached the village downstream damaging some buildings. A geomorphological analysis was initially carried out after surveying the whole basin. All liquid and solid-liquid contributions to the phenomenon were recognized together with the areas subjected to erosion and deposition. The elaboration of pre and post-event topographical surveys provided the map of deposition-erosion depths. Using the rainfall estimated by weather radar and corrected by the nearest rain gauge, about 0.8 km far, we estimated runoff by using a rainfall-runoff model designed for the headwater rocky basins of Dolomites. A triggering model provided the debris \ufb02ow hydrographs in the initiation areas, after using the simulated runoff. The initial solid-liquid surge hydrographs were, then, routed downstream by means of a cell model. The comparison between the simulated and estimated deposition-erosion pattern resulted satisfactory. The results of the simulation captured, in fact, the main features of the occurred phenomenon

    Mediatization of religion and Cultural Studies: a reading of Stuart Hall

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    Although the issue of religion does not occupy a prominent place in the works of Stuart Hall or even in Cultural Studies in general, some contemporary phenomena related to media and religion relations can be analyzed within this key of interpretation, mostly when we think on the intersection with identity. In this text, some theoretic and conceptual possibilities are outlined in order to understand the process of mediatization of religion from a perspective of articulation of identities, focusing, in particular, on questions related to body and culture.Embora a questão da religião não ocupe um lugar de destaque na obra de Stuart Hall ou mesmo no âmbito dos Estudos Culturais, alguns dos fenômenos contemporâneos direcionados para as relações entre Mídia e Religião podem ser analisados dentro desta chave de compreensão, sobretudo quando se pensa na intersecção com questões de identidade. Neste texto, são delineadas algumas possibilidades teórico-conceituais de compreensão dos processos de midiatização da religião a partir da perspectiva de articulações identitárias, focalizando, em particular, nas questões relacionadas a corpo e cultura

    The emerging role of the inwardly rectifying K+ channels in autism spectrum disorders and epilepsy

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    Autism is a complex behavioral disorder that develops prior to age three years and is distinguished by high heritability. Many genes predisposing to autism spectrum disorders (ASDs) have been identified. These findings have demonstrated that ASDs are etiologically heterogeneous; although, the mutations underlying ASDs are identifiable only in a minority of patients. Indeed, the causes of ASDs are unknown in more than 70% of patients. Recently, we have described two unrelated families whose affected individuals display a characteristic triad of symptoms of autism; such as impairments in social interaction, impairments in communication, restricted interests and repetitive behavior. They also displayed other symptoms commonly observed in autistic individuals; such as gait imbalance, clumsiness, mental retardation and epilepsy. The genetic analysis of these families resulted in the identification of new heterozygous point mutations in the KCNJ10 gene that encodes the inwardly-rectifying K+ channel Kir4.1 expressed predominantly, but not exclusively, in astrocytes. Functionally, the mutated channels exhibited a phenotype consistent with gain-of-function defects. These new findings highlight the emerging role of inwardly-rectifying K+ channels and astrocyte dysfunction in autism spectrum disorders associated with epilepsy.peer-reviewe

    High density piecewise syndeticity of product sets in amenable groups

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    M. Beiglb\"ock, V. Bergelson, and A. Fish proved that if GG is a countable amenable group and AA and BB are subsets of GG with positive Banach density, then the product set ABAB is piecewise syndetic. This means that there is a finite subset EE of GG such that EABEAB is thick, that is, EABEAB contains translates of any finite subset of GG. When G=ZG=\mathbb{Z}, this was first proven by R. Jin. We prove a quantitative version of the aforementioned result by providing a lower bound on the density (with respect to a F\o lner sequence) of the set of witnesses to the thickness of % EAB. When G=ZdG=\mathbb{Z}^d, this result was first proven by the current set of authors using completely different techniques.Comment: 7 pages; the proof of the main result has been simplified and sharpened by removing a technical assumption; also, a lower density version has been adde

    A monad measure space for logarithmic density

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    We provide a framework for proofs of structural theorems about sets with positive Banach logarithmic density. For example, we prove that if A⊆NA\subseteq \mathbb{N} has positive Banach logarithmic density, then AA contains an approximate geometric progression of any length. We also prove that if A,B⊆NA,B\subseteq \mathbb{N} have positive Banach logarithmic density, then there are arbitrarily long intervals whose gaps on A⋅BA\cdot B are multiplicatively bounded, a multiplicative version Jin's sumset theorem. The main technical tool is the use of a quotient of a Loeb measure space with respect to a multiplicative cut.Comment: 26 page

    On a sumset conjecture of Erd\H{o}s

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    Erd\H{o}s conjectured that for any set A⊆NA\subseteq \mathbb{N} with positive lower asymptotic density, there are infinite sets B,C⊆NB,C\subseteq \mathbb{N} such that B+C⊆AB+C\subseteq A. We verify Erd\H{o}s' conjecture in the case that AA has Banach density exceeding 12\frac{1}{2}. As a consequence, we prove that, for A⊆NA\subseteq \mathbb{N} with positive Banach density (a much weaker assumption than positive lower density), we can find infinite B,C⊆NB,C\subseteq \mathbb{N} such that B+CB+C is contained in the union of AA and a translate of AA. Both of the aforementioned results are generalized to arbitrary countable amenable groups. We also provide a positive solution to Erd\H{o}s' conjecture for subsets of the natural numbers that are pseudorandom.Comment: 17 pages; new version has a slightly different title, some minor typos are fixed, and the exposition of Lemma 4.6 has been improved. To appear in the Canadian Journal of Mathematic

    Organizing and Promoting Value Services in Public Sector by a New E-government Approach

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    To strengthen democracy, promote government efficiency and effectiveness, discourage wastes and misuses of government resources, public administrations have to promote a new stronger level of openness in government. The purpose of this manuscript is to describe an innovative approach for the governance of public systems and services, currently applied in the Italian public administration domain, which could be easily replicated in other countries as well. Two initiatives, to collect and provide relevant public information gathered from different and heterogeneous public organizations, to improve government processes and increase quality of services for citizens and companies, are described. The cases adopted have been validated through a case analysis approach involving the Italian Agency for the public administration digitalization to understand new e-government scenarios within the context of governmental reforms heavily influenced by the principles of Open Government Model.To strengthen democracy, promote government efficiency and effectiveness, discourage wastes and misuses of government resources, public administrations have to promote a new stronger level of openness in government. The purpose of this manuscript is to describe an innovative approach for the governance of public systems and services, currently applied in the Italian public administration domain, which could be easily replicated in other countries as well. Two initiatives, to collect and provide relevant public information gathered from different and heterogeneous public organizations, to improve government processes and increase quality of services for citizens and companies, are described. The cases adopted have been validated through a case analysis approach involving the Italian Agency for the public administration digitalization to understand new e-government scenarios within the context of governmental reforms heavily influenced by the principles of Open Government Model.Invited Submission

    Photonic applications of azobenzene molecules embedded in amorphous polymer

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    AbstractThe incorporation of azobenzene chromophores into polymer systems gives rise to a number of unique effects under UV and visible light irradiation. The light-driven isomerization of the azobenzene element acts as a light-to-mechanical energy converter, translating the nanoscopic structural movement of the isomerization azobenzene into macroscopic topographic film modulation in the form of surface relief. This review focuses on the study of reversible changes in shape in various systems incorporating azobenzene, including large-scale superficial photo-patterned glassy materials, light-driven reshaping of tridimensional superficial azo-textures and contractions of stimuli-responsive liquid crystalline networks (LCNs). Further, promising applications of azo systems are investigated as smart biointerfaces able to mimic time-varying biological systems
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