1,721,334 research outputs found
Magnetization profiles at the upper critical dimension as solutions of the integer Yamabe problem
No full textWe study the connection between the magnetization profiles of models described by a scalar field with marginal interaction term in a bounded domain and the solutions of the so-called Yamabe problem in the same domain, which amounts to finding a metric having constant curvature. Taking the slab as a reference domain, we first study the magnetization profiles at the upper critical dimensions d=3, 4, 6 for different (scale-invariant) boundary conditions. By studying the saddle-point equations for the magnetization, we find general formulas in terms of Weierstrass elliptic functions, extending exact results known in literature and finding ones for the case of percolation. The zeros and poles of the Weierstrass elliptic solutions can be put in direct connection with the boundary conditions. We then show that, for any dimension d, the magnetization profiles are solution of the corresponding integer Yamabe equation at the same d and with the same boundary conditions. The magnetization profiles in the specific case of the four-dimensional Ising model with fixed boundary conditions are compared with Monte Carlo simulations, finding good agreement. These results explicitly confirm at the upper critical dimension recent results presented in Gori and Trombettoni [J. Stat. Mech: Theory Exp. (2020) 0632101742-546810.1088/1742-5468/ab7f32]
Critical 1- and 2-point spin correlations for the O(2) model in 3d bounded domains
Full text linkWe study the critical properties of the 3d O(2) universality class in bounded domains through Monte Carlo simulations of the clock model. We use an improved version of the latter, chosen to minimize finite-size corrections at criticality, with 8 orientations of the spins and in the presence of vacancies. The domain chosen for the simulations is the slab configuration with fixed spins at the boundaries. We obtain the universal critical magnetization profile and two-point correlations, which favorably compare with the predictions of the critical geometry approach based on the Yamabe equation. The main result is that the correlations, once the dimensionful contributions are factored out with the critical magnetization profile, are shown to depend only on the distance between the points computed using a metric found solving the corresponding fractional Yamabe equation. The quantitative comparison with the corresponding results for the Ising model at criticality is shown and discussed. Moreover, from the magnetization profiles the critical exponent η is extracted and found to be in reasonable agreement with up-to-date results
New EU policy for coastal areas
No full textViene presa in analisi e discussa la politica marittima della UE.
“Europe is surrounded by many islands and by four seas: the Mediterranean, the Baltic, the North Sea and the Black Sea; and by two oceans: the Atlantic and the Arctic. This Continent is a peninsula with thousands of kilometres of coast - longer
than that of other large land masses such as the United States or the Russian Federation. This geographical reality means that over two thirds of the Union’s borders are coastal and that the maritime spaces under the jurisdiction of its Member States are larger than their terrestrial territory. Through its outermost regions, in
addition to the Atlantic Ocean, Europe is also present in the Indian Ocean and the Caribbean Sea. Their maritime stakes are many and concern the EU as a whole.” P3
“As the EU seeks to revitalise its economy, it is important to recognise the economic potential of her maritime dimension. Between 3 and 5% of Europe’s Gross Domestic
Product (GDP) is estimated to be generated by marine based industries and services, without including the value of raw materials, such as oil, gas or fish. The maritime
regions account for over 40% of GDP.
The evolution of the Marche Region coastal zone and the climate change
No full textCoastal Evolution in Marche Region and regional Planning.
The map and the sections show clearly oscilaltion of the ancient shorelines around the present day position of the shoreline. The situation changes going northwards in presence of the Emilia sandy littoral and the Venice lagoon with the Po plain on the back
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Comparative observations of the temporal geomorphological evolution of coastal zones in Greece and Northeastern Italy
No full textThe erosion phenomena - regression of extended parts of the coastal line, are a common element for both Greece as well as for Northeastern Italy and are seen even in areas where in the past there was a strong tendency of the coastline to move forward.
The common factor for this environmental destabilisation is the uncontrolled and unplanned human inerventions and most importantly the intensive exploitation of teh natural resources and the irrational economic exploitation of the coastal area and of the uphill ouflow basins. The present work, using the method of comparative observation attempts to define the individual causes which have led to the environmental destabilisation of the coastal parts under study,which are located in the outfalls of the rivers Arachthos (Western Greece) and Nestos (Northern Greece) and also in upper Adriatic Coasts (Italy)
Human interventions and alterations of the geomorphological characteristics in parts of the coastal area in the Ionian coasts (Ipiros-Greece)
No full textAccording to data results from in situ observations and the interpretation of aerial photography of the past, it arises that in general therms the state of the coasts in the study area is fragile, while there is a predominant tendency of regression of the coast line towards the inland
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
