187 research outputs found
Construction of symmetric cubic surfaces
No full textWe consider the action of the group PGL4(K) on the smooth cubic surfaces of PK3 (K an algebraically closed field of characteristic zero). We classify, in an explicit way, all the smooth cubic surfaces with nontrivial stabilizer, the corresponding stabilizers and obtain a geometric description of each group in terms of permutations of the Eckardt points, of the 27 lines or of the 45 tritangent planes
Leveraging Deep Learning models to assess the temporal validity of Emotional Text Mining procedures
No full textThe paper presents the training of a surrogate model to mimic the functioning of a text mining social profiling method, emotional Text Mining, applied on the Italian tweets containing #Covid-19 during the first lockdown. This surrogate model is based on stateof-the-art Deep learning models in the field of Natural language processing (Nlp). These models feature an architecture called Transformer, which adopts a mechanism of self-attention that weighs the significance of each part of the input data. The model was trained on the tweets and factors of an initial time period to predict the polarisation of a tweet according to each factor found using the ETM technique. The model was then applied to subsequent periods. Using appropriate metrics, it was then possible to quantify the need to re-run the technique from scratch on the following time periods, while also being able to assess which factors still remained relevant over time
Blood Upon the Rose: Easter Rising and Historical Trauma through the Lens of Comics
No full textThe recent success of such authors as Art Spiegelman, Joe Kubert and Marjane Satrapi highlighted the
comics’ potential in representing and questioning social traumas, collective memory and remembrance, thus
paving the way for a prolific and vivacious production of political and historical graphic novels which
undeniably deserves critical attention. This research focuses on the Irish author Gerry Hunt and, in particular,
on his work Blood Upon the Rose: Easter 1916: The Rebellion that Set Ireland Free published in 2009 by
O'Brien Press. Through the tragic story of Joseph Mary Plunkett and his girlfriend Grace Gifford, the 46-
page comics is a flashback narration which brings to life the salient moments of the rebellion fought in the
streets of Dublin in 1916. The present inquiry is centred around such a representation of conflict and political
violence in Ireland. Specifically, it aims at assessing how Hunt’s graphic novel relates to and portrays the
Irish past and fight for freedom by identifying multimodal forms and rhetorical as well as visual devices used
to depict the conflict on a linguistic, typographic and pictorial level. By virtue of such blending of verbal and
visual elements, Blood Upon the Rose gives a new, symbolic dimension to the representation of the Easter
Rising and its protagonists, and accordingly turns the readers into witnesses to socio-political events which
have shaped and still shape the Irish identity and history
Broadband CARS microscopy of biological samples
No full textCoherent anti-Stokes Raman Scattering (CARS) microscopy is a label-free vibrational imaging technique that delivers chemical maps of cells and tissues. Broadband CARS (BCARS) combines narrowband pump pulses with broadband Stokes pulses to record broad vibrational spectra. Despite many technological advancements, BCARS microscopes still struggle to image biological samples spanning the entire Raman active region of biological samples (400-3100 cm-1). Here, we demonstrate a novel BCARS method to answer this need. Our experimental setup is based on a femtosecond fiber laser at 1035 nm and 2 MHz repetition rate, thus delivering high energy pulses used for generating sub-20 fs broadband Stokes pulses by white-light continuum in a bulk YAG crystal, a compact and alignment-insensitive technique. Combining them with narrowband picosecond pulses, we can generate a CARS signal with high (< 10 cm-1) spectral resolution in the entire Raman window. The system is equipped with a home-made transmission microscope to image cells and tissue at high-speed (< 3 ms) and large field of views. Using a post-processing pipeline, we deliver high-quality chemical maps, identifying the main chemical compounds in cancer cells and discriminating tumorous from healthy regions in liver slices of mouse models, unveiling the path for applications in histopathological settings
Ultrabroadband Coherent Anti-Stokes Raman Scattering Microscopy for Biological Applications via Supercontinuum Generation in Bulk Crystals
No full textRecent years saw continual advances in coherent anti-Stokes Raman scattering (CARS) microscopy as a powerful tool to deliver chemical images of unstained cells and biological tissues at high speed. Narrowband CARS combines two picosecond pump pulses, namely pump and Stokes, whose frequency difference is resonant with a vibrational mode of the scrutinized sample. However, this configuration enables acquiring a single vibrational mode at a time. This calls for broadband approaches, able to merge the fast acquisition of coherent processes with the high chemical specificity of spontaneous Raman. Broadband CARS (BCARS)[1] employs the combination of a narrowband pump beam with a broadband Stokes beam to detect many vibrational modes at once. However, CARS suffers from a chemically unspecific background signal, known as non-resonant background (NRB), that arises from four wave-mixing processes. While, in the narrowband configuration, NRB limits the sensitivity and specificity of the technique and cannot be easily cancelled, in the broadband approach, it can be exploited to amplify the weak Raman modes of the fingerprint region (400-1800 cm-1). The line shape distortions can be removed in post-processing, exploiting either numerical methods or deep-learning approaches. Despite many improvements in the last decade, BCARS microscopes struggle to work in the fingerprint spectral region, because of a weaker Raman response than the high-frequency CH-stretching region (2800-3100 cm-1)
Efficacia terapeutica della polichemioterapia CcVPP nel morbo di Hodgkin
No full textIn questo lavoro vengono riportati i risultati ottenuti in 38 pazienti affetti da linfoma di Hodgkin, in diversi stadi, trattati con schemi terapeutici comprendenti la combinazione CcVPP (CCNU, vinblastina, procarbazina e prednisone).Dieci pazienti erano trattati solo con CcVPP, otto ricevevano terapia alternata CcVPP/ABVD e venti terapia combinata CcVPP/radiante. La combinazione CcVPP si dimostrava particolarmente efficace permettendo di ottenere una remissione completa in 26 pazienti (68%) e una remissione parziale in 9 pazienti (24%).A 36 mesi la sopravvivenza globale era pari al 78% e la sopravvivenza libera da malattia dei 26 pazienti responsivi pari all'85%.A parità di efficacia terapeutica, una migliore tolleranza gastroenterica, una minore neurotossicità e la somministrazione orale erano i principali vantaggi del CcVPP rispetto al MOPP
Broadband CARS microscopy in the entire Raman-active region of biological samples via supercontinuum generation in bulk media
No full textVideo-rate wide-field broadband CARS microscopy
No full textCoherent anti-Stokes Raman scattering is an extremely powerful non-linear optical (NLO) microscopy technique for label-free vibrational imaging allowing for chemical characterization of biological samples in their native state. We introduce here video-rate wide-field signal generation and acquisition over a large field of view (tens of micrometers) allowing for real-time investigation of fast biological dynamics. To this aim, our innovative approach employs an amplified femtosecond ytterbium laser source delivering high energy (≈ μJ) pulses in the near-infrared at 1035-nm central wavelength and 2-MHz repetition rate from which pump and Stokes beams are generated. Narrowband pump pulses with ≈1.1 nm bandwidth (10 cm−1) guarantee sufficient spectral resolution for the vibrational Lorentian peaks. Broadband Stokes pulses in the 1100-1500nm range are produced via supercontinuum generation in 10-mm YAG crystal and amplified in a non-collinear optical parametric amplifier (NOPA). This allows us to acquire hypercubes that cover the entire fingerprint region of the molecular vibrational spectrum, the richest in chemical information. Our results pave the way for future clinical diagnostics applications with video-rate imaging capabilities
Artificial Intelligence in Classical and Quantum Photonics
No full texthe last decades saw a huge rise of artificial intelligence (AI) as a powerful tool to boost industrial and scientific research in a broad range of fields. AI and photonics are developing a promising two-way synergy: on the one hand, AI approaches can be used to control a number of complex linear and nonlinear photonic processes, both in the classical and quantum regimes; on the other hand, photonics can pave the way for a new class of platforms to accelerate AI-tasks. This review provides the reader with the fundamental notions of machine learning (ML) and neural networks (NNs) and presents the main AI applications in the fields of spectroscopy and chemometrics, computational imaging (CI), wavefront shaping and quantum optics. The review concludes with an overview of future developments of the promising synergy between AI and photonics
- …
