1,720,970 research outputs found
Pearcey integrals, Stokes lines and exact baryonic layers in the low energy limit of QCD
Full text linkThe first analytic solutions representing baryonic layers living at finite baryon density within a constant magnetic field in the gauged Skyrme model are constructed. A remarkable feature of these configurations is that, if the Skyrme term is neglected, then these baryonic layers in the constant magnetic background cannot be found analytically and their energies grow very fast with the magnetic field. On the other hand, if the Skyrme term is taken into account, the field equations can be solved analytically and the corresponding solutions have a smooth limit for large magnetic fields. Thus, the Skyrme term discloses the universal character of these configurations living at finite Baryon density in a constant magnetic field. The classical gran-canonical partition function of these configurations can be expressed explicitly in terms of the Pearcey integral. This fact allows us to determine analytically the Stokes lines of the partition function and the corresponding dependence on the baryonic chemical potential as well as on the external magnetic field. In this way, we can determine various critical curves in the (μB−Bext) plane which separates different physical behaviors. These families of inhomogeneous baryonic condensates can be also dressed with chiral conformal excitations of the solutions representing modulations of the layers themselves. Some physical consequences are analyzed
Looking for Carroll Particles in the Two-Time Spacetime
No full textWe make an attempt to describe Carroll particles with a non-vanishing value of energy (i.e. the Carroll particles which always stay in rest) in the framework of
two time physics, developed in the series of papers by I. Bars and his co-authors. In the spacetime with one additional time dimension and one additional space dimension
one can localize the symmetry which exists between generalized coordinates and their conjugate momenta. Such a localization implies the introduction of the gauge fields, which in turn implies the appearance of some first-class constraints. Choosing different gauge-fixing conditions and solving the constraints one obtains different time parameters, Hamiltonians, and generally, physical systems in the standard one time spacetime. We find a set of gauge fixing conditions which gives the description of a Carroll particle in the one time world. Besides, we construct the quantum theory of such a particle using an unexpected correspondence between our parametrization and that obtained by Bars for the hydrogen atom in 1999
Disposizioni costruttive e "pratico rilievo. Note a margine dei nuovi rilievi (1992-2000)
No full textIl contributo è pubblicato nel volume edito in occasione degli ultimi restauri giubilari del Tempio Malatestiano di Rimini (1999-2000). Sulla campagna di rilevamento della fabbrica albertiana, iniziata nel 1992 e proseguita sino al dicembre del 2000, si è già avuto modo di riferire in altra occasione, qui si è puntata l’attenzione su quanto emerso dall’esame ravvicinato di quelle “disposizioni costruttive”- tecnologie edili antiche e materiali -, di cui parla G.Giovannoni in un suo scritto del 1925, consapevoli di quanto siano facili, ma senza dubbio limitate, le valutazioni su di un manufatto antico in cui il valore d’immagine risulti dominante.
Lo scritto analizza le tecniche di lavorazione, posa in opera e finitura del paramento lapideo esterno che degli elementi architettonici (semicolonne di facciata, pilastri ed archi, trabeazione) per poi passare allo studio delle strutture murarie del tempio. Queste costituiscono a tutt’oggi ancora uno degli aspetti meno indagati della fabbrica riminese, vengono pertanto qui esposti i primi risultati di una ricerca condotta sugli elementi caratterizzanti il paramento (dimensione dei laterizi, modalità di apparecchiatura, finitura, malte ed inerti, modalità di esecuzione dei giunti) acquisiti con una serie di campionature in contesti omogenei presumibilmente di fase. Nel capitolo vengono inoltre formulate alcune ipotesi sulla provenienza da territori limitrofi dei mattoni adoperati, che troverebbero diversi riscontri nelle carte d’archivio locali del XV secolo, a conferma della “debolezza” dell’industria laterizia riminese in età medievale. L’analisi su dimensioni ed ubicazione delle buche pontaie, seguita da alcune considerazioni sulle tipologie di ponteggi presumibilmente adoperati e sulla cantieristica quattrocentesca, sono redatte a conclusione del contributo
Indagini multispettrali sulle superfici del Tempio Malatestiano
No full textNell'articolo vengono presentati i risultati di una campagna di studio e di indagini multispettrali realizzate sulle superfici del Tempio Malatestiano di Rimini
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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