Shaping transverse beam distributions by means of adiabatic crossing of resonances

Non-linear effects are responsible for peculiar phenomena in charged particles dynamics in circular accelerators. Recently, they have been used to propose novel beam manipulations where one can modify the transverse beam distribution in a controlled way, to fulfil the constraints posed by new applications. One example is the resonant beam splitting used at CERN for the Multi-Turn Extraction (MTE), to transfer proton beams from PS to SPS. The theoretical description of these effects relies on the formulation of the particle's dynamics in terms of Hamiltonian systems and symplectic maps, and on the theory of adiabatic invariance and resonant separatrix crossing. Close to resonance, new stable regions and new separatrices appear in the phase space. As non-linear effects do not preserve the Courant-Snyder invariant, it is possible for a particle to cross a separatrix, changing the value of its adiabatic invariant. This process opens the path to new beam manipulations. This thesis deals with various possible effects that can be used to shape the transverse beam dynamics, using 2D and 4D models of particles' motion. We show the possibility of splitting a beam using a resonant external exciter, or combining its action with MTE-like tune modulation close to resonance. Non-linear effects can also be used to cool a beam acting on its transverse beam distribution. We discuss the case of an annular beam distribution, showing that emittance can be reduced modulating amplitude and frequency of a resonant oscillating dipole. We then consider 4D models where, close to resonance, motion in the two transverse planes is coupled. This is exploited to operate on the transverse emittances with a 2D resonance crossing. Depending on the resonance, the result is an emittance exchange between the two planes, or an emittance sharing. These phenomena are described and understood in terms of adiabatic invariance theory.

Populism as a battlefield Populist actors and their representation on social and legacy media during the european parliament elections 2019 in Finland, Italy and the Netherlands

The objective of the present research is to describe and explain populist actors and populism as a concept and their representation on social and legacy media during the 2019 EU elections in Finland, Italy and The Netherlands. This research tackles the topic of European populism in the context of political communication and its relation to both the legacy and digital media within the hybrid media system. Departing from the consideration that populism and populist rhetoric are challenging concepts to define, I suggest that they should be addressed and analyzed through the usage of a combination of methods and theoretical perspectives, namely Communication Studies, Corpus Linguistics, Political theory, Rhetoric and Corpus-Assisted Discourse Studies. This thesis considers data of different provenance. On the one hand, for the Legacy media part, newspapers articles were collected in the three countries under study from the 1st until the 31st of May 2019. Each country’s legacy system is represented by three different quality papers and the articles were collected according to a selection of keywords (European Union Elections and Populism in each of the three languages). On the other hand, the Digital media data takes into consideration Twitter tweets collected during the same timeframe based on particular country-specific hashtags and tweets by identified populist actors. In order to meet the objective of this study, three research questions are posed and the analysis leading to the results are exhaustively presented and further discussed. The results of this research provide valuable and novel insights on how populism as a theme and a concept is being portrayed in the context of the European elections both in legacy and digital media and political communication in general.

Victorian letter writing and its representation in literature and painting: the case study of love letters

One of the main features of nineteenth-century fiction is the quasi-total disappearance of the epistolary novel that had had its heydays in the previous century. For this reason, some scholars have declared the “death” of the letter in literature after the transitional romantic period. However, Victorian novels overflow with letters that are embedded, quoted in part or described and commented on by narrators or characters. Even when its content is not revealed to the reader, the letter becomes a signifier loaded with meanings, also and particularly so, when it is burnt, torn, hidden, found or buried. The Postal Reform of 1839-40 caused the number of letters sent every year in Britain to grow from 75 to 410 million in only 14 years, and the mediatic campaign that supported it drew the attention of the population to the material aspects concerning this means of communication. Newspapers became more affordable too and they promoted a taste for sensationalism that often involved the “spectacularization” of private correspondence. Starting from an excursus on the history of the letter aimed at identifying the key aspects of the genre, this work deals with some real love correspondences from people belonging to different classes in the period from 1840 to the 1870s, to then analyse their fictional and pictorial counterparts. The general picture that emerges from this analysis is that of a Victorian society where letters were able to break down the boundaries between high and low forms of cultural expressions and where, more than ever, letters were present in people’s everyday lives as well as in the art and literature they enjoyed.

SPHERA, a new Italian convection-permitting regional reanalysis: improving heavy-rainfall representation and describing hail-prone environments

Extreme weather events related to deep convection are high-impact critical phenomena whose reliable numerical simulation is still challenging. High-resolution (convection-permitting) modeling setups allow to switch off physical parameterizations accountable for substantial errors in convection representation. A new convection-permitting reanalysis over Italy (SPHERA) has been produced at ARPAE to enhance the representation and understanding of extreme weather situations. SPHERA is obtained through a dynamical downscaling of the global reanalysis ERA5 using the non-hydrostatic model COSMO at 2.2 km grid spacing over 1995-2020. This thesis aims to verify the expectations placed on SPHERA by analyzing two weather phenomena that are particularly challenging to simulate: heavy rainfall and hail. A quantitative statistical analysis over Italy during 2003-2017 for daily and hourly precipitation is presented to compare the performance of SPHERA with its driver ERA5 considering the national network of rain gauges as reference. Furthermore, two extreme precipitation events are deeply investigated. SPHERA shows a quantitative added skill over ERA5 for moderate to severe and rapid accumulations in terms of adherence to the observations, higher detailing of the spatial fields, and more precise temporal matching. These results prompted the use of SPHERA for the investigation of hailstorms, for which the combination of multiple information is crucial to reduce the substantial uncertainties permeating their understanding. A proxy for hail is developed by combining hail-favoring environmental numerical predictors with observations of ESWD hail reports and satellite overshooting top detections. The procedure is applied to the extended summer season (April-October) of 2016-2018 over the whole SPHERA spatial domain. The results indicate maximum hail likelihood over pre-Alpine regions and the northern Adriatic sea around 15 UTC in June-July, in agreement with recent European hail climatologies. The method demonstrates enhanced performance in case of severe hail occurrences and the ability to separate between ambient signatures depending on hail severity.

Advanced representation of the ocean/sea ice dynamics at high latitudes

Sea ice is a fundamental element of global climate system, with numerous impacts on the polar environment. The ongoing drastic changes in the Earth’s sea ice cover highlight the necessity of monitoring the polar regions and systematically evaluating the quality of different numerical products. The main objective of this thesis is to improve our knowledge of the representation of Arctic and Antarctic sea ice using comprehensive global ocean reanalyses and coupled climate models. The dissertation will explore (i) the Antarctic marginal ice zone (MIZ) and pack ice area in the ensemble mean of four global ocean reanalyses called GREP; (ii) historical representation of the Arctic and Antarctic sea ice state in HighResMIP models; (iii) the future evolution of Arctic sea ice in HighResMIP models. Global ocean reanalyses and GREP are found to adequately capture interannual and seasonal variability in both pack ice and MIZ areas at hemispheric and regional scales. The advantage of the ensemble-mean approach is proved as GREP smooths the strengths and weaknesses of single systems and provides the most consistent and reliable estimates. This work is intended to encourage the use of GREP in a wide range of applications. The analysis of sea ice representation in the coupled climate models shows no systematic impact of the increased horizontal resolution. We argue that a few minor improvements in sea ice representation with the enhanced horizontal resolution are presumably not worth the major effort of costly computations. The thesis highlights the critical importance to distinguish the MIZ from consolidated pack ice both for investigating changes in sea ice distribution and evaluating the product’s performance. Considering that the MIZ is predicted to dominate the Arctic sea ice cover, the model physics parameterizations and sea ice rheology might require modifications. The results of the work can be useful for modelling community.

Stochastic physics and representation of El Niño Southern Oscillation in climate models

El Niño-Southern Oscillation (ENSO) è il maggiore fenomeno climatico che avviene a livello dell’Oceano Pacifico tropicale e che ha influenze ambientali, climatiche e socioeconomiche a larga scala. In questa tesi si ripercorrono i passi principali che sono stati fatti per tentare di comprendere un fenomeno così complesso. Per prima cosa, si sono studiati i meccanismi che ne governano la dinamica, fino alla formulazione del modello matematico chiamato Delayed Oscillator (DO) model, proposto da Suarez e Schopf nel 1988. In seguito, per tenere conto della natura caotica del sistema studiato, si è introdotto nel modello lo schema chiamato Stochastically Perturbed Parameterisation Tendencies (SPPT). Infine, si sono portati due esempi di soluzione numerica del DO, sia con che senza l’introduzione della correzione apportata dallo schema SPPT, e si è visto in che misura SPPT porta reali miglioramenti al modello studiato.

Advancing Bag-of-visual-words Representations For Lesion Classification In Retinal Images.

Diabetic Retinopathy (DR) is a complication of diabetes that can lead to blindness if not readily discovered. Automated screening algorithms have the potential to improve identification of patients who need further medical attention. However, the identification of lesions must be accurate to be useful for clinical application. The bag-of-visual-words (BoVW) algorithm employs a maximum-margin classifier in a flexible framework that is able to detect the most common DR-related lesions such as microaneurysms, cotton-wool spots and hard exudates. BoVW allows to bypass the need for pre- and post-processing of the retinographic images, as well as the need of specific ad hoc techniques for identification of each type of lesion. An extensive evaluation of the BoVW model, using three large retinograph datasets (DR1, DR2 and Messidor) with different resolution and collected by different healthcare personnel, was performed. The results demonstrate that the BoVW classification approach can identify different lesions within an image without having to utilize different algorithms for each lesion reducing processing time and providing a more flexible diagnostic system. Our BoVW scheme is based on sparse low-level feature detection with a Speeded-Up Robust Features (SURF) local descriptor, and mid-level features based on semi-soft coding with max pooling. The best BoVW representation for retinal image classification was an area under the receiver operating characteristic curve (AUC-ROC) of 97.8% (exudates) and 93.5% (red lesions), applying a cross-dataset validation protocol. To assess the accuracy for detecting cases that require referral within one year, the sparse extraction technique associated with semi-soft coding and max pooling obtained an AUC of 94.2 ± 2.0%, outperforming current methods. Those results indicate that, for retinal image classification tasks in clinical practice, BoVW is equal and, in some instances, surpasses results obtained using dense detection (widely believed to be the best choice in many vision problems) for the low-level descriptors.

Goya And Tinea Favosa.

A case of a tinea favosa involving the scalp of a child represented in the painting Boys climbing a tree (Muchachos trepando a un árbol), by Francisco Goya y Lucientes, with pictorial representation of favic scutula and consequent alopecia.

Diagramas de Ellingham e de Van't Hoff: algumas considerações

The main subject of this article is to show the parallelism betwen the Ellingham and Van't Hoff diagrams. The first one is a graphic representation of the changes in the standard Gibbs free energy (deltarGtheta) as a function of T and was introduced by Ellingham in 1944, in order to study metallurgic processes involving oxides and sulphides. On the other hand, the Van't Hoff diagram is a representation of the function ln K versus (1/T). The equivalence between both diagrams is easily demonstrated, making simple mathematical manipulations. In order to show the parallelism between both diagrams, they are presented briefly and two examples are discussed. The comparison of the both diagrams surely will be helpful to students and teachers in their learning and teaching activities, and will certainly enrich important aspects of chemical thermodynamics.

Descrição e discriminação de formas de nervuras foliares utilizando a representação polinomial cúbica de Hermite

This paper describes a method for leaf vein shape characterization using Hermite polynomial cubic representation. The elements associated with this representation are used as secondary vein descriptors and their discriminatory potential are analyzed based on the identification of two legume species (Lonchocarpus muehlbergianus Hassl. and L. subglaucescens Mart, ex Benth.). The elements of Hermite geometry influence a curve along all its extension allowing a global description of the secondary vein course by a descriptor of low dimensionality. The obtained results shown the analyzed species can be discriminated by this method and it can be used in addition to commonly considered elements in the taxonomic process.

As Apocynaceae s. str. da região de Bauru, São Paulo, Brasil

The present study describes a survey of the Apocynaceae in different types of vegetation, in the region of Bauru, in the Center-West of São Paulo State. Of the 25 species encountered, distributed into 15 genera, representation ranges as follows: Forsteronia G. Mey, five species; Aspidosperma Mart., four species; Mandevilla Lindl., three species; Prestonia R. Br., two species; and Condylocarpon Desf., Hancornia Gomez, Himatanthus Willd. ex Roem. et Schult., Macrosiphonia Müll. Arg., Mesechites Müll. Arg., Odontadenia Benth, Peltastes Woodson, Rhodocalyx Müll Arg., Secondatia A. DC., Tabernaemontana L. and Temnadenia Miers, one species each. In addition to both distribution data, and flowering and fruiting times, identifications keys, descriptions and illustrations of the species are presented.

Formação de conceitos em crianças cegas: questões teóricas e implicações educacionais

Concept formation depends on language and thought, that promote the integration of information coming from the senses. It is postulated that changes in the person, the objects and events to be known suggest flexible models of concept teaching. It is assumed that the same considerations apply to teaching concepts to blind pupils. Specificities of this process are discussed, including the role of touch as resource, although not as a direct substitute to vision, and the notion of representation as a basis for the elaboration of pedagogical resources for the blind student.

A formação de personalidades éticas: representações de si e moral

The article presents studies of a current investigation among 75 adolescents from 12 to 15 years old, students of private schools of Campinas city, that have as main objective to notice a possible correspondence among the moral judgments and the representation that individuals have about themselves. From a questionnaire, the studies bring out the representations of these individuals and answer a questioning if they would have an ethical character or not and if these individuals would correspond to their moral judgments. The results point out to a correspondence among those whose self representations are characterized by more evolved ethical contents and judgments related to sensitivity and to the characters feelings involved in the situations described. Such studies validate the intention of this article to discuss the correspondences between ethics (how the individual sees himself/herself) and moral (how he/she judges the situations moral).

A metalinguagem como lugar da interpretação: terminologia e bases de dados informatizadas

The main objective of this work is to discuss the notion of metalanguage concerning the use of thesaurus (symbols systems, functions indicators, descriptors) utilized by indexers for article representation in computerized bibliographical databases. Our corpus comprises article abstracts and bibliographical database descriptors LILACS (Literatura Latino-Americana em Ciências da Saúde) and SOCIOFILE Sociological Abstracts. We aim at clarifying the effects of subjectivity in the functioning of indexing taking account the grounds for interpretation that allow different meanings.

A evolução da noção de parâmetros

This paper presents an overview of the concept of parameter in the Principles and Parameters theory, showing that a) in the first stage parameters were conceived as variation associated to the Principles and b) in the second stage as properties of the lexicon, and more specifically as properties of functional categories. The latter view has also developed from a substantive conception of functional categories to a more formal abstract characterization of functional heads. The paper also discusses parameters related to different levels of representation.