Elastic anomalies in glasses: the string theory understanding in the case of Glycerol and Silica

We present an implementation of the analytical string theory recently applied to the description of glasses. These are modeled as continuum media with embedded elastic string heterogeneities, randomly located and randomly oriented, which oscillate around a straight equilibrium position with a fundamental frequency depending on their length. The existence of a length distribution reflects then in a distribution of oscillation frequencies which is responsible for the Boson Peak in the glass density of states. Previously, it has been shown that such a description can account for the elastic anomalies reported at frequencies comparable with the Boson Peak. Here we start from the generalized hydrodynamics to determine the dynamic correlation function $S(k,\omega)$ associated with the coherent, dispersive and attenuated, sound waves resulting from a sound-string interference. Once the vibrational density of states has been measured, we can use it for univocally fixing the string length distribution inherent to a given glass. The density-density correlation function obtained using such distribution is strongly constrained, and able to account for the experimental data collected on two prototypical glasses: glycerol and silica. The obtained string length distribution is compatible with the typical size of elastic heterogeneities previously reported for silica and supercooled liquids, and the atomic motion associated to the string dynamics is consistent with the soft modes recently identified in large scale numerical simulations as non-phonon modes responsible for the Boson Peak. The theory is thus in agreement with the most recent advances in the understanding of the glass specific dynamics and offers an appealing simple understanding of the microscopic origin of the latter, while raising new questions on the universality or material-specificity of the string distribution properties.Comment: 15 pages, 8 figure

Effetti immunomodulatori di preparazioni fitoterapiche a base di Echinacea

In questa tesi ho analizzato studi in vitro ed in vivo sugli effetti immunomodulatori di preparazioni contenenti Echinacea purpurea, Echinacea pallida ed Echinacea angustifolia. Sulla base dei risultati ottenuti con gli studi in vivo, per il momento non è possibile affermare se le specie di Echinacea abbiano proprietà immunomodulatorie. I risultati di numerosi trials sono ottenuti con tecniche disomogenee, pertanto risulta impossibile comarare i risultati emersi dagli studi. Anche gli studi in vitro sull' attività immunomodulatoria dell' Echinacea hanno mostrato risultati controversi, mentre altri studi sulla sua attività antinfiammatoria propongono le alcamidi come una nuova classe di cannabinomimetici. This thesis analyzes in vivo and in vitro studies about remedies containing Echinacea purpurea, Echinacea pallida and Echinacea angustifolia. At present it's not possible to affirm if Echinacea species have immunomodulatory properties. Various trials results come from not univocal methods and so it is impossible to compare each other. In vitro studies also show controversial results about immunomodulatory activity of Echinacea species. Other in vitro studies show an interesting cannabinomimetic effect from Echinacea's alcamides

Mirative implicatures at the syntax-semantics interface : A surprising association and an unexpected move

Peer reviewe

Ignorance and competence implicatures in central Sicilian polar questions

Peer reviewe

Variation at the syntax–pragmatics interface : Discourse particles in questions

Peer reviewe

Ignorance and competence implicatures in central Sicilian polar questions

In this paper we examine the distribution and functions of two optional particles found in polar questions in the central Sicilian dialect of Mussomeli (Caltanissetta): chi and cusà. The import of these particles can best be understood by analysing their distribution in various types of ‘non-canonical’ questions, based on the typology outlined in Farkas (2020). In Farkas’s account, canonical questions are characterized by the default assumptions of speaker ignorance and addressee competence regarding the question’s propositional content, while at least one of these is missing in non-canonical questions. This characterization of (non)-canonical questions in terms of speaker ignorance and addressee competence allows us to capture the distribution of the two particles, which strengthen these assumptions to conventional implicatures. In particular, we show that chi is conventionally associated with addressee competence, while cusà is conventionally associated with speaker ignorance. We frame this analysis in a version of the inquisitive semantics model, according to which sentence types are characterized by two parameters: the informativeness of the propositional content relative to the participants’ information state, and its inquisitiveness, that is, its potential to raise an issue. This perspective allows us to develop an explicit analysis of the meaning of the particles, which can in turn be successfully extended to capture their uses beyond polar questions

Variation at the Syntax–Pragmatics Interface: Discourse Particles in Questions

This paper focuses on the microvariation concerning the distribution and functions of certain interrogative discourse particles found in several central and southern Italian dialects. These particles show many similarities in terms of both their morphological shapes (being homophonous to the wh-phrase corresponding to English ‘what’) and their syntactic distribution within the sentence, in that they all occur at the beginning of polar questions. However, a careful analysis of their distribution across a pragmatically defined typology of canonical and non-canonical polar questions shows that these particles are not possible in all question types. In particular, two patterns emerge: in Pattern B, the particle is associated with a conventional implicature that both the speaker and the addressee are competent with respect to the issue addressed by the polar question, while in Pattern A, this implicature is restricted to the addressee competence. This point of microvariation is then analysed by assuming that both the pragmatic assumptions of competence and the discourse participants are encoded in the syntactic representation; the cartographic framework is adopted to characterize the compositional structure