Resonance frequency and radiative Q-factor of plasmonic and dielectric modes of small objects

The electromagnetic scattering resonances of a non-magnetic object much smaller than the incident wavelength in vacuum can be either described by the electroquasistatic approximation of the Maxwell's equations if its permittivity is negative, or by the magnetoquasistatic approximation if its permittivity is positive and sufficiently high. Nevertheless, these two approximations fail to correctly account for the frequency shift and the radiative broadening of the resonances when the size of the object becomes comparable to the wavelength of operation. In this manuscript, the radiation corrections to the electroquasistatic and magnetoquasistatic resonances of arbitrarily-shaped objects are derived, which only depend on the quasistatic current modes. Then, closed form expressions of the frequency-shift and the radiative Q-factor of both plasmonic and dielectric modes of small objects are introduced, where the dependencies on the material and the size of the object are factorized. In particular, it is shown that the radiative Q-factor explicitly depends on the multipolar components of the quasistatic modes

Volume Integral Formulation for the Calculation of Material Independent Modes of Dielectric Scatterers

In the frame of volume integral equation methods, we introduce an alternative representation of the electromagnetic field scattered by a homogeneous object of arbitrary shape at a given frequency, in terms of a set of modes independent of its permittivity. This is accomplished by introducing an auxiliary eigenvalue problem, based on a volume integral operator. With this modal basis the expansion coefficients of the scattered field are simple rational functions of the permittivity of the scatterer. We show, by studying the electromagnetic scattering from a sphere and a cylinder of dimensions comparable to the incident wavelength, that only a moderate number of modes is needed to accurately describe the scattered far field. This method can be used to investigate resonant scattering phenomena, including plasmonic and photonic resonances, and to design the permittivity of the object to pursue a prescribed tailoring of the scattered field. Moreover, the presented modal expansion is computationally advantageous compared to direct solution of the volume integral equation when the scattered field has to be computed for many different values of the dielectric permittivity, given the size and shape of the dielectric body

Magnetoquasistatic resonances of small dielectric objects

A small dielectric object with positive permittivity may resonate when the free-space wavelength is large in comparison with the object dimensions if the permittivity is sufficiently high. We show that these resonances are described by the magnetoquasistatic approximation of the Maxwell's equations in which the normal component of the displacement current density field vanishes on the surface of the particle. They are associated to values of permittivities and frequencies for which source-free quasistatic magnetic fields exist, which are connected to the eigenvalues of a magnetostatic integral operator. We present the general physical properties of magnetoquasistatic resonances in dielectrics with arbitrary shape. They arise from the interplay between the polarization energy stored in the dielectric and the energy stored in the magnetic field. Our findings improve the understanding of resonances in high-permittivity dielectric objects and provide a powerful tool that greatly simplifies the analysis and design of high-index resonators

Genotype imputation using the Positional Burrows Wheeler Transform.

Genotype imputation is the process of predicting unobserved genotypes in a sample of individuals using a reference panel of haplotypes. In the last 10 years reference panels have increased in size by more than 100 fold. Increasing reference panel size improves accuracy of markers with low minor allele frequencies but poses ever increasing computational challenges for imputation methods. Here we present IMPUTE5, a genotype imputation method that can scale to reference panels with millions of samples. This method continues to refine the observation made in the IMPUTE2 method, that accuracy is optimized via use of a custom subset of haplotypes when imputing each individual. It achieves fast, accurate, and memory-efficient imputation by selecting haplotypes using the Positional Burrows Wheeler Transform (PBWT). By using the PBWT data structure at genotyped markers, IMPUTE5 identifies locally best matching haplotypes and long identical by state segments. The method then uses the selected haplotypes as conditioning states within the IMPUTE model. Using the HRC reference panel, which has ∼65,000 haplotypes, we show that IMPUTE5 is up to 30x faster than MINIMAC4 and up to 3x faster than BEAGLE5.1, and uses less memory than both these methods. Using simulated reference panels we show that IMPUTE5 scales sub-linearly with reference panel size. For example, keeping the number of imputed markers constant, increasing the reference panel size from 10,000 to 1 million haplotypes requires less than twice the computation time. As the reference panel increases in size IMPUTE5 is able to utilize a smaller number of reference haplotypes, thus reducing computational cost

Il ruolo del genere nel lavoro con gli uomini autori di violenza: Affetti e rappresentazioni dei professionisti della salute

Il lavoro di contrasto alla violenza maschile contro le donne ha recentemente spostato il proprio focus dalla donna vittima di violenza all’uomo maltrattante. Questo cambio di paradigma ha portato all’implementazione di programmi di trattamento rivolti agli autori di violenza e all’impegno di professionisti uomini nel contrasto alla violenza. Il presente studio ha l’obiettivo di esplorare gli affetti e le rappresentazioni di 7 professionisti della salute (3 uomini e 4 donne) che si occupano di trattare uomini autori di violenza, con un focus specifico sul genere di appartenenza. L’analisi semiotica quali-quantitativa applicata alle interviste semi-strutturate analizzate tramite il software T-LAB ha consentito di individuare la presenza di 5 cluster: 1) Riconoscimento delle emozioni; 2) Posizionamento di genere; 3) Competenze lavorative; 4) Percezione del rapporto tra i generi; e 5) Rapporto con il lavoro. I risultati sembrano confermare che il genere di appartenenza degli operatori giochi un ruolo fondamentale nell’esperienza lavorativa con gli uomini maltrattanti

Tra manoscritti e libri della biblioteca di Elsa Morante: genesi e significati del Mondo salvato dai ragazzini

This thesis work stems from the intention to highlight one of Elsa Morante's least studied works: Il mondo salvato dai ragazzini (The World Saved by Kids). Published by Einaudi in 1968, it is probably the Roman writer’s most heterogeneous, multiform, and complex to interpret book. A first reason for the difficult collocation of this text lies in the impossibility of ascribing it to conventional categorisations of literary genre: it alternates between verse, prose, theatrical drama, visual poetry experiments, and non-semiotic codes of writing (staves, drawings) that make systematisation complex. A second reason can be traced back to the painful existential and writing phase Morante went through during the years of elaboration of the work, due to the problematic nature of her experiences: the death of her mother Imma Poggibonsi and lover Bill Morrow, a loss that marks the entire book, the controversial relationship with the hallucinogenic substances, alternately seen as a source of creativity and an impossible escape from a painful reality. Added to this is the traumatic clash with History and all the monstrous and sinister obscenities of the 20th century (the war, the Shoah, the consequences of autocratic capitalism) that, up to that point, seemed to be only the background of her narrative production. Moreover, it is necessary to consider the connection of The World saved by Kids, published in 1968, with the events of those years, so strong that Goffredo Fofi said that it is «the highest document of 1968 and its surroundings» (FOFI: 1969, 225) But although the references to the youth protest are quite explicit, the 1968 utopia becomes in Morante's work the embodiment of a more general revolutionary aspiration. The choral revolt of the Kids, the book’s protagonists and recipients, is indeed a meta-historical reality: a rebellion against social constraints, technocratic regimes, authoritarian thinking, ideological superstructures, and conceptual constraints that deprive young people, and poets, of their most authentic voice. Chapter One describes the writer's personal and cultural journey in the years between 1964 and 1967, period of writing The World Saved by Kids, as reflected in various notations in the autograph papers that appear to be fundamental for the identification of a terminus post quem and ante quem within which to place the writing of the work. Through the analysis of the book’s main structural and formal features (internal subdivisions and overall architecture), the fundamental role that verse production plays in the literary and existential horizon of an author mostly known for her novels emerges. The second part of this chapter acts as a bridge to the next one: here, in fact, the discussion on the manuscripts and typescripts of The Word Saved by Kids is introduced through an analysis of Morante's writing practice: from the incessant labor limae that touches single words as well as entire sections of text to the structured planning of the arrangement of the archive material that appears almost already designed, in the author's intention, for readers' consultation. In Chapter Two, an attempt is made to reconstruct the genetic-evolutionary path of the work through the consultation of autograph material conserved at the Biblioteca Nazionale Centrale di Roma in the Vittorio Emanuele 1622 and Archivi Raccolte e Carteggi 52 I 4.3 funds. Following the examination of the papers and the subsequent full transcription of the text contained therein, the main macroscopic changes to the entire work were identified (titles; subdivision into sections and subsections; deletion of entire parts). However, due to the dense layering of corrections in the papers, it was decided in the course of the work to include in the thesis all macro-textual considerations related to the book as a whole, but to restrict the philological analysis to a single section, The Chemical Comedy, which in turn comprises two lyric poems, a play and a long verse story divided into eleven compositions. This choice was motivated both by the central structural position of The Chemical Comedy, the junction point between the opening poem Farewell and the Folk Songs that close the volume, and by the complexity of its genesis. Indeed, it is the part of the book that has undergone, in the transition from the first draft to the final one, passing through numerous intermediate drafts, the greatest number of remakes, revisions and even aesthetic and substantial distortions. To follow the diachronic evolution of the text and to functionalise the philological discourse to a critical investigation of the book, it was therefore preferred to give a transcription of the verses, as transmitted by the papers in the most relevant editorial phases, and not to include a philological apparatus that would have hindered the readability of the study. However, to account for the frenetic movement of variants and to avoid transcribing uninteresting lessons because they are adiaphora or synonymous, the most notable microscopic variants have been selected in terms of stylistic or content changes and in relation to the communicative strategies adopted. A second line of research has made it possible to combine the study of the antecedent with a timely survey of literary, philosophical and artistic suggestions inspired by ancient or contemporary works. Important, in this sense, are the paratextual sections that sometimes contain quotations, translations and references to the texts of other authors; however, the consultation of the volumes of the writer's personal library, today kept in the Fondo Morante of the Biblioteca Nazionale Centrale in Rome, has been fundamental. The numerous books are underlined, annotated, and often consumed by passionate and voracious reading; Morante's annotations therefore allow us to reflect on the intertextuality of a work that arises from a «dense weaving of references, borrowings, echoes and literary quotations». When identifying Morante's main cultural coordinates, however, the dynamic and multifaceted link that the author establishes with tradition has not been overlooked. Chapter Three traces, from the books in the library, an itinerary among the main models of the work, either textually displayed or only alluded to. The first authors referred to are the poets of the American beat counterculture, first and foremost Allen Ginsberg, who in those years inspired Morante in terms of experience, thematic choices, and language. There follows a section devoted to Greek tragedies and to some of the numerous readaptations and reinterpretations of classical myth in contemporary theatre, from Brecht to the Living Theatre: Morante recovers, combines, and rewrites them in the play at the centre of the book, The Evening at Colonus. The essential core of this chapter is then the discussion of Morante's connection with Simone Weil's philosophy on the dual level of religious mysticism and ideological commitment. Beginning with the dense annotations found in the philosopher's books kept in Morante's library, Weil's thought is tackled from the perspective of an organic relationship with The World Saved by Kids, a work that turns out to be entirely built on the oscillation between the two Weilian poles of grâce and pesanteur. While the influence exerted by the French philosopher's meditations on Morante is undoubted, it is more interesting to highlight the profound convergences on the issues addressed by Weil. The last part of the chapter deals with the essay The End of the World: Cultural Apocalypse and Transcendence by the anthropologist Ernesto de Martino, a text that Morante possesses and comments on as evidenced by the reading marks in her edition. De Martino's considerations make it possible to identify a distinction between the representation of the cultural apocalypse in The World Saved by Kids and the psychopathological apocalypse in the latest novel Aracoeli; at the same time, they offer an interpretative key to discover new and dialoguing meanings in the interaction between the two works. The Fourth Chapter takes up the results that emerged from the previous chapters and finalises them into an analysis of the book from the perspective of trauma studies. The aim is to propose a re-reading of the work as a narration in verse of individual and collective traumatic experiences, investigating the narrative devices and expressive choices made by the author to verbalise them. In this sense, the parts of the text that were not included in the final draft, the books read by the author, and the link with her models also help to shed light on the ellipses of a past and present that are traumatic on both a personal and historical level. A two-part Appendix concludes the thesis. The first, which responds to the aim of reorganising and arranging the autograph papers in sequential order, contains an accurate description of the manuscript and typescript corpus: factual characteristics of the folios, collation, binding, presence of notes in the notebook plates, attachments. The second is intended to provide a schematic review of some of the books Morante frequented during the years of writing The Word Saved by Kids with a precise indication of the presence of any apostilles, reading marks and dedications. This work of cataloguing, of certain help to the critical discourse developed in the thesis, could also be preliminary to future studies that, based on the author's personal library, would contribute to a deeper knowledge of her human and cultural journey

Synthesis of resonant modes in electromagnetics

Resonant modes determine the response of electromagnetic devices, including dielectric and plasmonic resonators. Relying on the degrees of freedom that metamaterials provide, this contribution shows how to design, at will, the resonant modes of a dielectric object placed in an unbounded space. Specifically, the proposed method returns in analytical form the spatial distribution of the dielectric susceptibility tensor for which the object exhibits resonances at prescribed frequencies and spatial distribution of the polarization. Together with the synthesis of the material, two key concepts are introduced: the controlled tunability of the resonant modes and the number of essential modes, i.e. the number of modes that uniquely characterize the spatial distribution of the dielectric susceptibility. Moreover, this approach can be applied to design the resonant modes of any system where the constitutive relationship is linear and local

Ghrelin Increases Beta-Catenin Level through Protein Kinase A Activation and Regulates OPG Expression in Rat Primary Osteoblasts.

Ghrelin, by binding growth hormone secretagogue receptor (GHS-R), promotes osteoblast proliferation but the signaling mechanism of GHS-R on these cells remains unclear. Since canonical Wnt/β-catenin pathway is critically associated with bone homeostasis, we investigated its involvement in mediating ghrelin effects in osteoblasts and in osteoblast-osteoclast cross talk. Ghrelin (10(-10)M) significantly increased β-catenin levels in rat osteoblasts (rOB). This stimulatory action on β-catenin involves a specific interaction with GHS-R1a, as it is prevented by the selective GHS-R1a antagonist, D-Lys(3)-GHRP-6 (10(-7)M). The effect of ghrelin on β-catenin involves the phosphorylation and inactivation of GSK-3β via protein kinase A (PKA). Inhibition of PKA activity reduces the facilitatory action of ghrelin on β-catenin stabilization. Ghrelin treatment of rOB significantly increases the expression of osteoprotegerin (OPG), which plays an important role in the regulation of osteoclastogenesis, and this effect is blocked by D-Lys(3)-GHRP-6. Furthermore, ghrelin reduced RANKL/OPG ratio thus contrasting osteoclastogenesis. Accordingly, conditioned media from rOB treated with ghrelin decreased the number of multinucleated TRAcP+ cells as compared with the conditioned media from untreated-control rOB. Our data suggest new roles for ghrelin in modulating bone homeostasis via a specific interaction with GHSR-1a in osteoblasts with subsequent enhancement of both β-catenin levels and OPG expression