Probing Quantum Gravity Through Exactly Soluble Midi-Superspaces I

It is well-known that the Einstein-Rosen solutions to the 3+1 dimensional vacuum Einstein's equations are in one to one correspondence with solutions of 2+1 dimensional general relativity coupled to axi-symmetric, zero rest mass scalar fields. We first re-examine the quanization of this midi-superspace paying special attention to the asymptotically flat boundary conditions and to certain functional analytic subtleties associated with regularization. We then use the resulting quantum theory to analyze several conceptual and technical issues of quantum gravity.Comment: 28 pages, late

False News On Social Media: A Data-Driven Survey

In the past few years, the research community has dedicated growing interest to the issue of false news circulating on social networks. The widespread attention on detecting and characterizing false news has been motivated by considerable backlashes of this threat against the real world. As a matter of fact, social media platforms exhibit peculiar characteristics, with respect to traditional news outlets, which have been particularly favorable to the proliferation of deceptive information. They also present unique challenges for all kind of potential interventions on the subject. As this issue becomes of global concern, it is also gaining more attention in academia. The aim of this survey is to offer a comprehensive study on the recent advances in terms of detection, characterization and mitigation of false news that propagate on social media, as well as the challenges and the open questions that await future research on the field. We use a data-driven approach, focusing on a classification of the features that are used in each study to characterize false information and on the datasets used for instructing classification methods. At the end of the survey, we highlight emerging approaches that look most promising for addressing false news

Topology comparison of Twitter diffusion networks effectively reveals misleading information

In recent years, malicious information had an explosive growth in social media, with serious social and political backlashes. Recent important studies, featuring large-scale analyses, have produced deeper knowledge about this phenomenon, showing that misleading information spreads faster, deeper and more broadly than factual information on social media, where echo chambers, algorithmic and human biases play an important role in diffusion networks. Following these directions, we explore the possibility of classifying news articles circulating on social media based exclusively on a topological analysis of their diffusion networks. To this aim we collected a large dataset of diffusion networks on Twitter pertaining to news articles published on two distinct classes of sources, namely outlets that convey mainstream, reliable and objective information and those that fabricate and disseminate various kinds of misleading articles, including false news intended to harm, satire intended to make people laugh, click-bait news that may be entirely factual or rumors that are unproven. We carried out an extensive comparison of these networks using several alignment-free approaches including basic network properties, centrality measures distributions, and network distances. We accordingly evaluated to what extent these techniques allow to discriminate between the networks associated to the aforementioned news domains. Our results highlight that the communities of users spreading mainstream news, compared to those sharing misleading news, tend to shape diffusion networks with subtle yet systematic differences which might be effectively employed to identify misleading and harmful information.Comment: A revised new version is available on Scientific Report

Aspecto, espacio y tiempo en el Nuevo Testamento: el uso en los modos no indicativos

The aspect value in the Greek Verbal System is connected to those of time and space. Beginning with the content of a recently published book on verbal aspect in non indicative moods in the New Testament, this article focuses especially on the relationship between these three ideas. A central point of the article is the affirmation that temporality operates as a semantic and not pragmatic component in some uses of the indicative, of the participle and of the infinitive.La noción de aspecto en el sistema verbal griego está conectada con la de espacialidad y tiempo. A partir del contenido de un volumen de reciente publicación sobre el aspecto verbal en los modos no indicativos del Nuevo Testamento, en el artículo se pone de relieve, sobre todo, la relación entre las tres nociones. Un punto central del contenido del artículo es la afirmación según la cual la temporalidad opera como componente semántico y no pragmático en algunos usos del indicativo, del particpio y del infinitivo

Perífrasis verbales con εἰμί más participio en las variantes del Pentateuco de los LXX

Nell’articolo sono raccolte e discusse le varianti con εἰμί più participio individuate nei testimoni della tradizione testuale del Pentateuco dei LXX; sono considerate anche le varianti con γίνομαι ma solo quelle concerneti il predicato nominale. La finalità è di osservare se vi siano tracce dell’affermazione della perifrasi nelle varianti, eventuali concentrazioni di frequenza insieme a sfumature d’uso, con particolare attenzione alla datazione dei testimoni dove appaiono. Un paragrafo è riservato anche alle varianti di costruzioni con predicato nominale (copula + aggettivo) rispetto a un verbo finito.The present article gathers and discusses the variants with εἰμί and the participle found in the testimonies of the textual traditions of the Pentateuch of the Lxx. They are also considered the variants with γίνομαι but only those concerning the nominal predicate. The purpose is to observe if there are traces of the affirmation of the periphrasis in the variants, perhaps concentrations of frequency together with undertones of use, with special attention to the dating of the testimonies where they are to be found. One paragraph is reserved to the variants of construction with the nominal predicate (copula + adjective) with respect to a finite verb

Del genitivo epexegético en el Nuevo Testamento

Este artículo propone una lectura inversa del genitivo epexegético, pero no de todos sus usos. Esta interpretación parte del hecho que invierte el papel de los términos. Cuando Pablo habla de la “señal de la circuncisión”, el trata de especificar la señal (determinado) como circuncisión (determinante), ¿o tal vez cualifica la circuncisión como señal? En otros términos, el apóstol con la circuncisión intentó explicar qué es una señal, ¿o quizás (también) quiso decir que la circuncisión es una señal? En este artículo se analizan varios casos de genitivo epexegético que figuran en la garmática de Wallace a partir de una doble pregunta: en el genitivo epexegético, ¿es el determinante el que clarifica exclusivamente al determinado?, o todo lo contrario, es decir, ¿es precisamente el determinado el que clarifica en qué términos el autor da a entender el determinante?This essay proposes an inverse reading of the epexegetical genitive, but not of all of its uses. This interpretation arises from the question that inverts the role of the terms. When Paul speaks of the “sign of circumcision” he intends to specify the sign (determined) as circumcision (determiner) or perhaps qualify the circumcision as sign? In other words, the apostle with circumcision intended to explain what a sign is, or perhaps he (also) wanted to say that circumcision is a sign? Various cases of the epexegetical genitive found in Wallace’s grammar book are discussed in this article. It begins with the double question: In the epexegetic genitive, it is the determiner that exclusively clarifies the determined or the contrary may occur, that is to say that it is precisely the determined that clarifies in what terms the author meant the determiner

Casos de adición de la διαστολή en el Códice Vaticano Gr. 1209

El artículo estudia casos de adición de la διαστολή en el Codex Vaticanus gr. 1209. Esta adición puede advertirse, asimismo, en pasajes del Nuevo Testamento y en la Septuaginta donde se utiliza el pronominal ὅτι. Este artículo sostiene que, en los pasajes examinados, la adición responde a propósitos filológicos en lugar de obedecer a razones de lectura. La διαστολή, de hecho, podría ser una especie de firma involuntaria que ayuda a establecer o confirmar los puntos clave antes de que el codex llegase a la Biblioteca Vaticana en 1475.This article studies some instances of the addition of διαστολή in the Codex Vaticanus gr. 1209. This addition may also be observed in some passages of the New Testament and the Lxx where the pronominal ὅτι is used. The article affirms that in the passages examined, the addition is more for philological than for reading reasons. Διαστολή could in fact be a kind of accidental signature that helps to fix or confirm fixed points before the codex came to the Vatican Library in 1475

Application of a virtual scientific experiment model in different educational contexts

E-learning practice is continuously using experimentation in order to enhance the basic information transfer model where knowledge is passed from the system/ tutors to the students. Boosting student productivity through on-line experimentation is not simple since many organizational, educational and technological issues need to be dealt with. This work describes the application of a Learning Model for Virtual Scientific Experiments (VSEs) in two different scenarios: Information and Communication Technologies and Physics. As part of the first, a VSE for Wireless Sensor Networks was specified and deployed while the second involved the specification and design of a collaborative VSE for physics experiments. Preliminary implementation and deployment results are also discussed