86,644 research outputs found
Advanced Techniques in Optimization for Machine Learning and Imaging
No full textIn recent years, non-linear optimization has had a crucial role in the development of modern techniques at the interface of machine learning and imaging. The present book is a collection of recent contributions in the field of optimization, either revisiting consolidated ideas to provide formal theoretical guarantees or providing comparative numerical studies for challenging inverse problems in imaging. The work of these papers originated in the INdAM Workshop “Advanced Techniques in Optimization for Machine learning and Imaging” held in Roma, Italy, on June 20-24, 2022.
The covered topics include non-smooth optimisation techniques for model-driven variational regularization, fixed-point continuation algorithms and their theoretical analysis for selection strategies of the regularization parameter for linear inverse problems in imaging, different perspectives on Support Vector Machines trained via Majorization-Minimization methods, generalization of Bayesian statistical frameworks to imaging problems, and creation of benchmark datasets for testing new methods and algorithms
Pubbliche virtù e vizi privati ne "La conquista di Roma" di Matilde Serao.
No full textL’intervento è incentrato sull’opera di Matilde Serao intitolata La conquista di Roma (1885), la quale si muove sullo sfondo
della vita politica della Roma umbertina e può senz’altro essere inserita nel filone del romanzo parlamentare. Si propone una
lettura del testo attenta sia all’aspetto istituzionale descritto dall’autrice, e sia a ciò che si cela dietro la maschera del pubblico, e
che è quanto di più sfuggente e imprevedibile: Roma, prima di ogni altra cosa, città incantatoria quanto indifferente, madre e
matrigna, fonte di speranze luminose così come di feroci disillusioni. Il ritratto di Francesco Sangiorgio, protagonista del racconto,
sarà naturalmente oggetto di studio, osservato nel suo doppio movimento di personaggio politico e insieme di raffinato mondano e
seduttore. Attraverso il suo esempio, prototipo del classico eroe decadente e allo stesso tempo rappresentate della vita politica
italiana postunitaria, sarà possibile delineare lo scenario prescelto da Matilde Serao, il teatro così come il dietro le quinte di un
momento fragile ma audace della storia italiana, un ambiente, quello romano, in cui privato e pubblico convergono verso un
orizzonte duplice: di spettacolo ma pure di riflessione, di concretezza ed evasione
From a discrete model of chemotaxis with volume-filling to a generalized Patlak–Keller–Segel model
No full textWe present a discrete model of chemotaxis whereby cells responding to a chemoattractant are seen as individual agents whose movement is described through a set of rules that result in a biased random walk. In order to take into account possible alterations in cellular motility observed at high cell densities (i.e. volume-filling), we let the probabilities of cell movement be modulated by a decaying function of the cell density. We formally show that a general form of the celebrated Patlak–Keller–Segel (PKS) model of chemotaxis can be formally derived as the appropriate continuum limit of this discrete model. The family of steady-state solutions of such a generalized PKS model are characterized and the conditions for the emergence of spatial patterns are studied via linear stability analysis. Moreover, we carry out a systematic quantitative comparison between numerical simulations of the discrete model and numerical solutions of the corresponding PKS model, both in one and in two spatial dimensions. The results obtained indicate that there is excellent quantitative agreement between the spatial patterns produced by the two models. Finally, we numerically show that the outcomes of the two models faithfully replicate those of the classical PKS model in a suitable asymptotic regime
CONVEX REGULARIZATION IN STATISTICAL INVERSE LEARNING PROBLEMS
No full textWe consider a statistical inverse learning problem, where the task is to estimate a function f based on noisy point evaluations of Af, where A is a linear operator. The function Af is evaluated at i.i.d. random design points u(n), n = 1, ..., N generated by an unknown general probability distribution. We consider Tikhonov regularization with general convex and p-homogeneous penalty functionals and derive concentration rates of the regularized solution to the ground truth measured in the symmetric Bregman distance induced by the penalty functional. We derive concrete rates for Besov norm penalties and numerically demonstrate the correspondence with the observed rates in the context of X-ray tomography
Untargeted metabolomics analytical strategy based on liquid chromatography/electrospray ionization linear ion trap quadrupole/orbitrap mass spectrometry for discovering new polyphenol metabolites in human biofluids after acute ingestion of Vaccinium myrtillus berry supplement
No full textIn this work, liquid chromatography, coupled with an electrospray ionization hybrid linear ion trap quadrupole/Orbitrap mass spectrometry, has been used to accurately identify polyphenol metabolites in human serum and urine after acute ingestion of a V. myrtillus berry supplement. The supplement was obtained by cryo-milling of bilberries, which were freeze-dried within 1 week after their harvesting, to maintain the berry native composition. Thirty-six derivatives of benzoic acids, hydroxyhippuric acids, cinnamic acids, phenylpropionic acids, phenylvaleric acids, phenylpentenoic acids and abscisic acid, together with two berry-native anthocyanins, one flavonol metabolite and two catechol derivatives were putatively identified in the investigated biofluids. The annotated compounds included 13 metabolites, among glucuronides and sulphates of phenylvaleric and phenylpentenoic acids, which have been identified for the first time in human biofluids after ingestion of V. myrtillus berries. It should be emphasized that the presence of phenylvaleric and phenylpentenoic acid derivatives is in agreement with their origin from fruit native flavanol monomers and oligomers, which are widely distributed in Vaccinium berries, but usually overlooked in metabolomics studies regarding bilberry. The identification of these compounds confirmed the key-role of untargeted metabolomics approach in the discovery of new metabolites which could be biologically activ
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[Freedom Rock by Ray "Bubba" Sorensen II, 4]
No full textPhotograph of the original Freedom Rock by Ray "Bubba" Sorensen II. The painting on the rock depicts three scenes: A military pilot flying a plane, and a building structure exploding behind him (left); a member of the New York Fire Department waking with an American flag (center); and a group of people wearing colonial clothing in a sailboat (right). Above the center panel, a quote reads, "'Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and success of freedom.' - John F. Kennedy, 1961." Part of a quote by George W. Bush can be seen above the left panel. The POW/MIA flag has been painted on the top portion of the rock. A field of grass can be seen behind the rock in the background of the photograph
Evaluation of pomological and nutritional characteristics of ‘Kaki Tipo’ and ‘Rojo Brillante’ persimmon fruits at the ripe-stage eating quality
No full textPersimmon fruit ‘Kaki Tipo’ (PVNA), a cultivar widely grown in Italy, is mostly marketed as seedless soft fruit, while ‘Rojo Brillante’ (PVA), the leading variety in Spain, is commercialized as firm fruit after artificial removal of astringency. In this study, fruits of both cultivars were purchased in a local supermarket at the ripe-stage eating quality and analyzed for their pomological and nutritional characteristics. Fruit weight, size, color, consistency, titratable acidity, total soluble solids, as well as the amount of different sugars were assessed. Nutritional quality of persimmons included ascorbic acid, polyphenols, and antioxidant capacity assessed by three different analytical methods (FRAP, ABTS, DPPH). The antioxidant capacity was evaluated in fresh tissue and after a simulated digestion to assess its dietary significance to the consumer. The chemical characterization of the fresh fruits for a number of individual polyphenols was also performed by LC-MS/MS analysis. Main polyphenols identified in both persimmon cultivars belonged to the flavanol (e.g., catechin and catechin-3-gallate), flavonol (e.g. quercetin glycoside) and phenolic acid (e.g., gallic acid) classes. Significant differences were highlighted in the composition pattern for ‘Kaki Tipo’ and ‘Rojo Brillante’ persimmons
Variations on the Author
No full text“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
[Freedom Rock by Ray "Bubba" Sorensen II, 2]
No full textPhotograph of the original Freedom Rock by Ray "Bubba" Sorensen II. The painting on the rock depicts two scenes: A member of the New York Fire Department waking with an American flag (left), and a group of people wearing colonial clothing in a sailboat (right). Above the left panel, a quote reads, "'Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and success of freedom.' - John F. Kennedy, 1961." Part of a quote by Thomas Jefferson can be seen above the right panel. The POW/MIA flag has been painted on the top portion of the rock. A field of grass can be seen behind the rock in the background of the photograph
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