cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
ADVANCEMENTS IN X-RAY IMAGING TECHNIQUES: ENHANCING DIAGNOSTIC ACCURACY AND RADIATION SAFET
Creators: name: Bander AA. Alfarsi, Khaled D. Alkhaormani, Mohammed A. Almazrouie, Fahad A. Alghanmi, Ahmed J. Aljeddani, Haifaa Almotiri, Banan H. Abkar, Maram Alharbi
Publisher: name: Zenodo
Year: 2023

description: Artificial intelligence (AI) has gained significant attention in the field of X-ray imaging, offering the potential to enhance various aspects of image-guided interventions. This paper explores the applications of AI algorithms in X-ray imaging, focusing on their impact on diagnostic accuracy, workflow optimization, and image quality improvement. Convolutional neural networks (CNNs) have demonstrated remarkable performance in detecting fractures, lung nodules, and other pathologies in X-ray images (Litjens et al., 2017). Computer-aided diagnosis (CAD) systems powered by AI assist radiologists in image analysis by automatically flagging potential abnormalities or regions of interest (Shen et al., 2019). AI algorithms further optimize workflow by prioritizing critical cases and automating repetitive tasks (Chartrand et al., 2017). Additionally, AI techniques such as generative adversarial networks (GANs) enhance image quality and reduce radiation dose by generating synthetic images and performing denoising (Wolterink et al., 2017). However, challenges related to training data, interpretability, and integration into clinical practice need to be addressed. Collaborative efforts among healthcare institutions and regulatory bodies are necessary to develop standardized datasets, establish transparent decision-making processes, and ensure the safe and responsible use of AI in X-ray imaging.
Discovery of an Extremely Short Duration Flare from Proxima Centauri Using Millimeter through FUV Observations
Creators: name: MacGregor, Meredith A.
name: Weinberger, Alycia J.
name: Loyd, R. O. Parke
name: Shkolnik, Evgenya
name: Barclay, Thomas
name: Howard, Ward S.
name: Zic, Andrew
name: Osten, Rachel A.
name: Cranmer, Steven R.
name: Kowalski, Adam F.
name: Lenc, Emil
name: Youngblood, Allison
name: Estes, Anna
name: Wilner, David J.
name: Forbrich, Jan
name: Hughes, Anna
name: Law, Nicholas M.
name: Murphy, Tara
name: Boley, Aaron
name: Matthews, Jaymie
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We present the discovery of an extreme flaring event from Proxima Cen by ASKAP, ALMA, HST, TESS, and the du Pont Telescope that occurred on 2019 May 1. In the millimeter and FUV, this flare is the brightest ever detected, brightening by a factor of >1000 and >14000 as seen by ALMA and HST, respectively. The millimeter and FUV continuum emission trace each other closely during the flare, suggesting that millimeter emission could serve as a proxy for FUV emission from stellar flares and become a powerful new tool to constrain the high-energy radiation environment of exoplanets. Surprisingly, optical emission associated with the event peaks at a much lower level with a time delay. The initial burst has an extremely short duration, lasting for <10 sec. Taken together with the growing sample of millimeter M dwarf flares, this event suggests that millimeter emission is actually common during stellar flares and often originates from short burst-like events.
description: 11 pages, 4 figures, 1 appendix, published in ApJ Letters
The complexity and applications of circuit minimization
Creators: name: Myrisiotis, Dimitrios
Publisher: name: Imperial College London
Year: 2021

description: The main topic of this thesis is the study of the Minimum Circuit Size Problem (MCSP). MCSP is a decision problem: Given the truth table of a finite Boolean function and a size parameter 0 <= theta <= 2^n - 1 (in binary), is there a Boolean circuit C of size at most theta such that C computes f? MCSP is an important problem due to its unexpected connections to many other areas of complexity theory, such as learning, pseudorandomness, and average-case complexity. In a similar manner, Kolmogorov complexity poses the following question: Given a string x, what is the size of the smallest program that outputs x when run on the empty string? While Kolmogorov complexity cannot be computed, in general, there are resource-bounded versions of Kolmogorov complexity that are computable and have been very influential in complexity theory, just like MCSP is. In this work, we study MCSP and some of its Kolmogorov complexity counterparts, and answer the following two questions. 1. What is the complexity of MCSP? That is, how easy or difficult is it to compute MCSP? We prove MCSP lower bounds against several restricted models of computation. These, among others, include formulas, branching programs, constant-depth circuits, and one-tape Turing machines. Almost all of the above lower bounds are the first of their kind for MCSP, and almost match the state-of-the-art lower bounds against these models. 2. What are some interesting applications of MCSP? Here, we show that the average-case hardness of a conditional Kolmogorov complexity counterpart of MCSP is almost equivalent to the existence of one-way functions (OWFs). Along with the concurrent and independent work by Liu and Pass, this is one of the first natural NP-complete problems whose average-case hardness is shown to be (almost) equivalent to the existence of OWFs.
Pure Tensor Program Rewriting via Access Patterns (Representation Pearl)
Creators: name: Smith, Gus Henry
name: Liu, Andrew
name: Lyubomirsky, Steven
name: Davidson, Scott
name: McMahan, Joseph
name: Taylor, Michael
name: Ceze, Luis
name: Tatlock, Zachary
Publisher: name: arXiv
Year: 2021
Subjects: subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences

description: Tensor kernels in machine learning (ML) often correspond to pure mathematical expressions, making term rewriting an attractive strategy for optimization and mapping to specialized hardware accelerators. However, existing ML intermediate representations (IRs) tend to either be \textit{pure but high-level}, making low-level rewrites to hardware targets inexpressible, or \textit{low-level but impure}, hampering the use of term rewriting altogether. This paper introduces Glenside, a pure IR whose core abstraction -- the \textit{access pattern} -- enables low-level, layout-aware, hardware-centric program rewrites. We demonstrate how term rewriting in Glenside can be used to map program fragments to hardware accelerator invocations and automatically discover classic data layout transformations like \texttt{im2col}. Glenside establishes a new foundation for exploring further term rewriting techniques in optimizing low-level tensor programs.
description: To be published at MAPS 2021
Mapping Solar Magnetic Fields from the Photosphere to the Base of the Corona
Creators: name: Ishikawa, Ryohko
name: Bueno, Javier Trujillo
name: Aleman, Tanausu del Pino
name: Okamoto, Takenori J.
name: McKenzie, David E.
name: Auchere, Frederic
name: Kano, Ryouhei
name: Song, Donguk
name: Yoshida, Masaki
name: Rachmeler, Laurel A.
name: Kobayashi, Ken
name: Hara, Hirohisa
name: Kubo, Masahito
name: Narukage, Noriyuki
name: Sakao, Taro
name: Shimizu, Toshifumi
name: Suematsu, Yoshinori
name: Bethge, Christian
name: De Pontieu, Bart
name: Dalda, Alberto Sainz
name: Vigil, Genevieve D.
name: Winebarger, Amy
name: Ballester, Ernest Alsina
name: Belluzzi, Luca
name: Stepan, Jiri
name: Ramos, Andres Asensio
name: Carlsson, Mats
name: Leenaarts, Jorrit
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Routine ultraviolet imaging of the Sun's upper atmosphere shows the spectacular manifestation of solar activity; yet we remain blind to its main driver, the magnetic field. Here we report unprecedented spectropolarimetric observations of an active region plage and its surrounding enhanced network, showing circular polarization in ultraviolet (Mg II $h$ & $k$ and Mn I) and visible (Fe I) lines. We infer the longitudinal magnetic field from the photosphere to the very upper chromosphere. At the top of the plage chromosphere the field strengths reach more than 300 gauss, strongly correlated with the Mg II $k$ line core intensity and the electron pressure. This unique mapping shows how the magnetic field couples the different atmospheric layers and reveals the magnetic origin of the heating in the plage chromosphere.
description: 50 pages, 11 figures, 1 table, published in Science Advances
Causality and emergence in complex systems: Perspectives from information theory
Creators: name: Rajpal, Hardik
Publisher: name: Imperial College London
Year: 2021

description: Information theory is becoming increasingly useful in the field of complex systems. In part because of the greater availability of data from various real-world systems but especially because of its ability to capture complex interdependencies in systems with many interacting parts. This thesis explores many such applications of information theory on a wide range of systems to understand two central themes in complexity sciences: \textit{Causality} and \textit{Emergence}. Inspired by Judea Pearl's ladder of causation, the type of analysis conducted in order to achieve the goals of this thesis are divided into three main parts, \textit{Associations}, \textit{Interventions} and \textit{Modelling}. These are the three probes used in this thesis to study causality in complex systems in this thesis. The first part deals with passively observing local, network-level and higher-order differences in the statistical associations in the brain activity that lead to an altered resting-state perception in schizophrenia. Here we find two interesting differences, firstly an increase in directed functional connectivity from frontal to the posterior brain regions and abnormal higher-order information processing in the parietal region of the brain. In the second part, we study the improvisational state of mind in musicians by studying their brain activity. We also explore the impact of this intervention on the audience that witnesses this improvisation in a concert-experiment setting. The findings here relate closely to the entropic brain hypothesis and yield useful and objective measures of engagement among the audience. Finally, we explore models of perception, opinion dynamics and evolution in the later part of this thesis that uses mathematical modelling to explore emergent phenomena like psychosis, polarization and species-environment interactions. These models enable us to highlight the role of aberrant Bayesian priors in schizophrenia and psychedelics, echo chambers in polarization and higher-level organization of species in ecosystems.
Spatio-temporal modeling of traffic accidents incidence on urban road networks based on an explicit network triangulation
Creators: name: Chaudhuri, Somnath
name: Juan, Pablo
name: Mateu, Jorge
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biotechnology
subject: Environmental Sciences not elsewhere classified
subject: Ecology
subject: FOS: Biological sciences
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified
subject: Cancer
subject: Infectious Diseases
subject: FOS: Health sciences

description: Traffic deaths and injuries are one of the major global public health concerns. The present study considers accident records in an urban environment to explore and analyze spatial and temporal in the incidence of road traffic accidents. We propose a spatio-temporal model to provide predictions of the number of traffic collisions on any given road segment, to further generate a risk map of the entire road network. A Bayesian methodology using Integrated nested Laplace approximations with stochastic partial differential equations (SPDE) has been applied in the modeling process. As a novelty, we have introduced SPDE network triangulation to estimate the spatial autocorrelation restricted to the linear network. The resulting risk maps provide information to identify safe routes between source and destination points, and can be useful for accident prevention and multi-disciplinary road safety measures.
Nonlinear finite-Larmor-radius effects in reduced fluid models
Creators: name: Brizard, A. J.
name: Denton, R. E.
name: Rogers, B.
name: Lotko, W.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: The polarization and magnetization effects associated with the dynamical reduction leading to the nonlinear gyrokinetic Vlasov-Maxwell equations are shown to introduce nonlinear finite-Larmor-radius effects into a set of nonlinear reduced-fluid equations previously derived by Lagrangian variational method [A.J. Brizard, Phys. Plasmas 12, 092302 (2005)]. These intrinsically nonlinear FLR effects, which are associated with the transformation from guiding-center phase-space dynamics to gyrocenter phase-space dynamics, are different from the standard FLR corrections associated with the transformation from particle to guiding-center phase-space dynamics. We also present the linear dispersion relation and results from a nonlinear simulation code using these reduced-fluid equations. The simulation results (in both straight and dipole geometries) demonstrate that the equations describe the coupled dynamics of Alfven and sound waves and that the total simulation energy is conserved.
description: 18 pages, 6 figures
Bi-Legendrian manifolds and paracontact geometry
Creators: name: Montano, Beniamino Cappelletti
Publisher: name: arXiv
Year: 2007
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53C15, 53C25

description: We study the interplays between paracontact geometry and the theory of bi-Legendrian manifolds. We interpret the bi-Legendrian connection of a bi-Legendrian manifold M as the paracontact connection of a canonical paracontact structure induced on M and then we discuss many consequences of this result both for bi-Legendrian and for paracontact manifolds. Finally new classes of examples of paracontact manifolds are presented.
description: to appear in Int. J. Geom. Meth. Mod. Phys
The THESEUS space mission: science goals, requirements and mission concept
Creators: name: Amati, L.
name: O'Brien, P. T.
name: Götz, D.
name: Bozzo, E.
name: Santangelo, A.
name: Tanvir, N.
name: Frontera, F.
name: Mereghetti, S.
name: Osborne, J. P.
name: Blain, A.
name: Basa, S.
name: Branchesi, M.
name: Burderi, L.
name: Caballero-García, M.
name: Castro-Tirado, A. J.
name: Christensen, L.
name: Ciolfi, R.
name: De Rosa, A.
name: Doroshenko, V.
name: Ferrara, A.
name: Ghirlanda, G.
name: Hanlon, L.
name: Heddermann, P.
name: Hutchinson, I.
name: Labanti, C.
name: Floch, E. Le
name: Lerman, H.
name: Paltani, S.
name: Reglero, V.
name: Rezzolla, L.
name: Rosati, P.
name: Salvaterra, R.
name: Stratta, G.
name: Tenzer, C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: THESEUS, one of the two space mission concepts being studied by ESA as candidates for next M5 mission within its Comsic Vision programme, aims at fully exploiting Gamma-Ray Bursts (GRB) to solve key questions about the early Universe, as well as becoming a cornerstone of multi-messenger and time-domain astrophysics. By investigating the first billion years of the Universe through high-redshift GRBs, THESEUS will shed light on the main open issues in modern cosmology, such as the population of primordial low mass and luminosity galaxies, sources and evolution of cosmic re-ionization, SFR and metallicity evolution up to the "cosmic dawn" and across Pop-III stars. At the same time, the mission will provide a substantial advancement of multi-messenger and time-domain astrophysics by enabling the identification, accurate localisation and study of electromagnetic counterparts to sources of gravitational waves and neutrinos, which will be routinely detected in the late '20s and early '30s by the second and third generation Gravitational Wave (GW) interferometers and future neutrino detectors, as well as of all kinds of GRBs and most classes of other X/gamma-ray transient sources. In all these cases, THESEUS will provide great synergies with future large observing facilities in the multi-messenger domain. A Guest Observer programme, comprising Target of Opportunity (ToO) observations, will expand the science return of the mission, to include, e.g., solar system minor bodies, exoplanets, and AGN.
description: Submitted to Experimental Astronomy. arXiv admin note: text overlap with arXiv:2102.08702
Loss in hybrid qubit-bus couplings and gates
Creators: name: Louis, Sebastien G. R.
name: Munro, W. J.
name: Spiller, T. P.
name: Nemoto, Kae
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We provide a characterization and analysis of the effects of dissipation on oscillator assisted (qubus) quantum gates. The effects can be understood and minimized by looking at the dynamics of the signal coherence and its entanglement with the continuous variable probe. Adding loss in between successive interactions we obtain the effective quantum operations, providing a novel approach to loss analysis in such hybrid settings. We find that in the presence of moderate dissipation the gate can operate with a high fidelity. We also show how a simple iteration scheme leads to independent single qubit dephasing, while retaining the conditional phase operation regardless of the amount of loss incurred by the probe.
description: 11 pages, 7 figures
Exploration of the high-redshift universe enabled by THESEUS
Creators: name: Tanvir, N. R.
name: Floc'h, E. Le
name: Christensen, L.
name: Caruana, J.
name: Salvaterra, R.
name: Ghirlanda, G.
name: Ciardi, B.
name: Maio, U.
name: D'Odorico, V.
name: Piedipalumbo, E.
name: Campana, S.
name: Noterdaeme, P.
name: Graziani, L.
name: Amati, L.
name: Bagoly, Z.
name: Balázs, L. G.
name: Basa, S.
name: Behar, E.
name: Bozzo, E.
name: De Cia, A.
name: Della Valle, M.
name: De Pasquale, M.
name: Frontera, F.
name: Gomboc, A.
name: Götz, D.
name: Horvath, I.
name: Hudec, R.
name: Mereghetti, S.
name: O'Brien, P. T.
name: Osborne, J. P.
name: Paltani, S.
name: Rosati, P.
name: Sergijenko, O.
name: Stanway, E. R.
name: Szécsi, D.
name: Toth, L. V.
name: Urata, Y.
name: Vergani, S.
name: Zane, S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: At peak, long-duration gamma-ray bursts are the most luminous sources of electromagnetic radiation known. Since their progenitors are massive stars, they provide a tracer of star formation and star-forming galaxies over the whole of cosmic history. Their bright power-law afterglows provide ideal backlights for absorption studies of the interstellar and intergalactic medium back to the reionization era. The proposed THESEUS mission is designed to detect large samples of GRBs at $z>6$ in the 2030s, at a time when supporting observations with major next generation facilities will be possible, thus enabling a range of transformative science. THESEUS will allow us to explore the faint end of the luminosity function of galaxies and the star formation rate density to high redshifts; constrain the progress of re-ionisation beyond $z\gtrsim6$; study in detail early chemical enrichment from stellar explosions, including signatures of Population III stars; and potentially characterize the dark energy equation of state at the highest redshifts.
description: Submitted to Experimental Astronomy
Flow boiling in horizontal pipes: integral measurements, optical diagnostics, and numerical simulations
Creators: name: Moran, Hannah Rosina
Publisher: name: Imperial College London
Year: 2021

description: Flow boiling in horizontal pipes is the heat transfer mechanism central to a wide variety of applications including refrigeration systems, high-temperature heat pumps, organic Rankine cycle systems and concentrating solar power plants operating in the direct steam generation mode. Refrigerants such as R245fa often serve as the working fluid in these applications, but few studies have been published investigating flow boiling of R245fa in pipes of sizes above the micro-scale. There is a lack of detailed data available with high spatial and temporal resolution for boiling flows, which could enhance fundamental understanding of the hydrodynamic and thermal behaviour and aid effective design and operation of heat transfer systems. Numerical simulation of boiling flows can complement detailed experimental data, but it presents a complex computational challenge, particularly in macro-scale geometries. This work presents experimental and numerical investigations towards a full description of flow boiling. A bespoke experimental facility was constructed for flow boiling of R245fa in a horizontal 12.6 mm pipe, and an experimental database has been populated with measurements of pressure drops, heat transfer coefficients and flow patterns. Laser-induced fluorescence and particle image velocimetry techniques were also developed and successfully applied in this facility, providing detailed spatio-temporally resolved interfacial property, phase distribution and liquid-phase velocity-fi eld data. Predictive methods in the literature are compared to experimental data and improvements suggested based on the optical measurements of interface location. Numerical simulations of elongated bubble flow provide new insights into the effects of buoyancy and inertia on bubble shape and dynamics. A new theoretical model for the fi lm thickness around the bubble is presented and compared to experimental data. A phase change model is validated in OpenFOAM for growth of a small bubble, and is then used to simulate stratifi ed flow based on a set of experimental conditions from this work.
Utilizzo dell’Abciximab nel paziente anziano con sindrome coronarica acuta trattato con strategia invasiva:           Effetti sulla prognosi
Creators: name: Furbatto, Fulvio
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2010

description: L'età avanzata è un predittore indipendente di mortalità dopo angioplastica coronarica (PTCA)nei pazienti affetti da Sindrome coronarica acuta senza innalzamento del tratto ST (SCA NSTEMI). Gli inibitori delle glicoproteine IIb/IIIa migliorano la prognosi nei pazienti ad alto rischio ma pochi e contrastanti dati sono disponibili nei pazienti anziani. Abbiamo quindi esaminato una popolazione consecutiva di pazienti anziani (> 75 anni) sottoposti a PTCA per SCA NSTEMI. 500 pazienti sono stati divisi in due gruppi: GPI (247 pazienti con età media 77 ± 1,9 anni) trattati con PTCA ed impianto di stent associato a somministrazione di abciximab ed un secondo gruppo noGPI (253 pazienti con età media 77 ± 2,4 anni)trattati con sola PTCA ed impianto di stent. Durante la degenza ospedaliera l'incidenza di morte è stata simile nei due gruppi (3,2% Vs 4,6%)senza differenze in termini di sanguinamenti maggiori (1,6% Vs 1,1%) e minori (4% Vs 3%). Al follow up a lungo termine la mortalità è stata significativamente minore nel gruppo GPI (4,5% Vs 12,3% P=0,002) così come il tasso di infarto miocardio (2,8% Vs 11,1% P=0,0001) e di re-PTCA (5,7% Vs 13,4% P=0003). La regressione di COX ha identificato l'abciximab come un predittore indipendente di minore incidenza di maggiori eventi cardiaci avversi (MACE)dopo aggiustamento con propensity score. I nostri dati suggeriscono come l'aggiunta di abciximab alla PTCA con impianto di stent, migliori la prognosi nei pazienti anziani con SCA NSTEMI, con un assoluto beneficio in termini di riduzione di mortalità e MACE e con un accettabile tasso di sanguinamenti maggiori e minori.
Additional file 1 of Antibiotics and antibiotic-associated diarrhea: a real-world disproportionality study of the FDA adverse event reporting system from 2004 to 2022
Creators: name: Huang, Haining
name: Li, Lanfang
name: Wu, Mingli
name: Liu, Zhen
name: Zhao, Yanyan
name: Peng, Jing
name: Ren, Xiaolei
name: Chen, Shuai
Publisher: name: figshare
Year: 2023
Subjects: subject: Space Science
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Genetics
subject: Pharmacology
subject: Biotechnology
subject: Immunology
subject: FOS: Clinical medicine
subject: Information Systems not elsewhere classified
subject: Science Policy
subject: Mental Health
subject: Infectious Diseases
subject: FOS: Health sciences

description: Additional file 1: Table S1. Onset times of AAD associated with each antibiotic. Table S2. Mortality rate for AAD associated with antibiotics.
Le meunier, la femme et Saint Denis, ou comment miniaturiser Paris au XIIIe siècle
Creators: name: Saint-Cricq, Gaël
Publisher: name: Pavia University Press - Edizioni dell'Università degli Studi di Pavia
Year: 2023

description: Sebbene il Medioevo sia un periodo caratterizzato dall’interesse verso le summae, anche le forme brevi hanno goduto di una certa fortuna. Per quanto concerne la musica del XIII sec., i mottetti vernacolari, per via del loro monostrofismo e dello stile sillabico, si presentano in modo del tutto diverso rispetto alle forme ‘prolisse’ come l’organum, il conductus e la chanson. Questo contributo è dedicato a uno dei brani più brevi del repertorio, il mottetto Hé! Monnier! (PRETI)OSUS. Si tratta di una composizione caratterizzata da una marcata brevità e dal contrasto fra le due voci: un mugnaio e una donna sono al centro di una scena caratterizzata da un linguaggio osceno, ma il tenor su cui si basa la struttura musicale è tratta da un responsorio per la festa di Saint Denis. L’articolo illustra le funzioni di questa forma breve, contestualizzando questo motetus drammatico all’interno della letteratura e della musica medievale e moderna, sviscerando il meccanismo che lega questa formula folcloristica con il frammento monodico di Saint Denis.
description: Philomusica on-line, Vol 22, N° 1 (2023): Musica e letteratura al tempo di Dante
Leptogenesis within a generalized quark-lepton symmetry
Creators: name: Buccella, F.
name: Falcone, D.
name: Oliver, L.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Quark-lepton symmetry has been shown to be inconsistent with baryogenesis via leptogenesis in natural schemes of the see-saw mechanism. Within the phenomenological approach of textures, we relax this strict symmetry and propose weaker conditions, namely models of the neutrino Dirac mass matrix $M_D$ which have the same hierarchy as the matrix elements of $M_u$. We call this guide-line generalized $hierarchical$ quark-lepton symmetry. We consider in detail particular cases in which the moduli of the matrix elements of $M_D$ are equal to those of $M_u$. Within the phenomenological approach of textures, we try for the heavy Majorana mass matrix diagonal and off-diagonal forms. We find that an ansatz for $M_D$ preserving the hierarchy, together with an off-diagonal model for the heavy Majorana neutrino mass, is consistent with neutrino masses, neutrino mixing and baryogenesis via leptogenesis for an intermediate mass scale $m_R \sim 10^{12}$ GeV. The preservation of the hierarchical structure could come from a possible symmetry scheme.
description: 12 pages, RevTex4. Title and abstract changed. Revised and enlarged version
title: The monsoon crush : rethinking Indian cinema's art-commerce divide in the context of transnationalism, corporatisation and liberalisation
Creators: name: Pal, Shorna
Publisher: name: University of St Andrews
Year: 2020

description: My thesis identifies and establishes the Multiplex Film as a widespread paradigm in contemporary Indian Cinema, by critically examining its emergence from the post-millennium collapse of All-India and Alternative films, often referred to as Indian “art” and “commercial” films, previously well-established and seemingly distinct categories that have historically defined and characterised Indian cinema. I assert that reading pre-millennium Indian films by applying the Rasa analytical method, reveals multiple meeting points between All-India and Alternative Films, which have been obfuscated through a historic misconstruction and mislabelling of these film types; I contend that this interconnectedness expedites their convergence into the Multiplex Film. By tracing the contemporary phenomenon as a product of the Indian government’s economic liberalisation and globalisation policies, and the resultant corporatisation and transnationalism within the 21st century film industries in Mumbai and in other regional filmmaking centres, I present a way of studying Multiplex Films both as Indian Cinema as well as Transnational Cinema, while also contributing to the limited scholarship on the contemporary Indian film industries. My use of rasa in conjunction with generic dramatic principles detailed in the Natyasastra, an ancient Indian treatise on dramaturgy, offers a new Rasa framework that can be used to read any national cinema, as it functions independently of rasa as an aesthetic. Through a series of forty-five interviews across seven cities with personnel from the Hindi, Bengali, Tamil, Telegu, Marathi and Assamese film industries, including writers, directors, actors, producers, cinematographers, editors, sound designers, distributors, exhibitors, alongside spectator focus groups in metropolitan and smaller cities, in addition to close textual analysis of a range of Indian films, existing scholarship, official government and film industry reports, I re-examine assumptions about Indian film history and show how the earlier two film types are metamorphosed through contemporary socioeconomic, political and industrial shifts into the Multiplex Film.
Cyber-attack: What Goes Around, Comes Around!
Creators: name: Barker, Ken
Publisher: name: The School of Public Policy Publications
Year: 2019

description: The Canadian Government recently introduced a new document entitled “Strong, Secure, and Engaged” (SSE) outlining Canada’s Defense Policy across a wide-range of its activities.   One very new factor of SSE is the decision to develop active cyber-attack capabilities to potentially employ against potential adversaries. This raises some key issues including: (i) the potential implications of using cyber-attacks, (ii) the potential for unintended consequences arising as a result of using such, and (iii) the risks associated with subsequent use against the attacker either intentionally or accidentally. Overarching questions include defining under what circumstances cyber-attacks should be permitted and what should be done to ensure they cannot subsequently be used against us or lead to harming one of our allies? Canada’s allies have already developed and deployed such weapons with some demonstrable success but with some unintended consequences. What can we learn from the available information about the safe use of cyber-attacks and when is it reasonable to use such a weapon? The nature of this technology is different than other forms of military aggression used in either peace or war time. What checks and balances need to be put in place to ensure that it is used only under appropriate government-authorized military oversight? What protections can be put in place to ensure that the inadvertent release of a cyber-attack cannot occur? Finally, the decision to endorse the development a cyber-attack capability introduces a difficult dichotomy. Cyber-attack technology exploits discovered weaknesses in digital systems. In a regime that only permits cyber-defence activities, the discovery of weaknesses and deploying a repair for the discovered weakness is an obvious choice. However, if Canada is to incorporate a cyber-attack strategy, the decision to repair the weakness must now be traded-off against exploiting the weakness against an enemy. These undiscovered weaknesses are known as zero-day attacks because a previously unknown vulnerability in a computer system (hardware or software) is exploited “on the same day” the vulnerability becomes known to the wider world.
description: The School of Public Policy Publications, Vol 12 (2019)
Scaling Theories of Kosterlitz-Thouless Phase Transitions
Creators: name: Zuo, Zhiyao
name: Yin, Shuai
name: Cao, Xuanmin
name: Zhong, Fan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We propose scaling theories for Kosterlitz-Thouless (KT) phase transitions on the basis of the hallmark exponential growth of their correlation length. Finite-size scaling, finite-entanglement scaling, short-time critical dynamics, and finite-time scaling, as well as some of their combinations are studied. Relaxation times of both a usual power-law and an unusual power-law with a logarithmic factor are considered. Finite-size and finite-entanglement scaling forms somehow similar to a frequently employed ansatz are presented. The Kibble-Zurek scaling of topological defect density for a linear driving across the KT transition point is investigated in detail. An implicit equation for a rate exponent in the theory is derived and the exponent varies with the distance from the critical point and the driving rate consistent with relevant experiments. To verify the theories, we utilize the KT phase transition of a one-dimensional Bose-Hubbard model. The infinite time-evolving-block-decimation algorithm is employed to solve numerically the model for finite bond dimensions. Both a correlation length and an entanglement entropy in imaginary time and only the entanglement entropy in real-time driving are computed. Both the short-time critical dynamics in imaginary time and the finite-time scaling in real-time driving, both including the finite bond dimension, for the measured quantities are found to describe the numerical results quite well via surface collapses. The critical point is also estimated and confirmed to be $0.302(1)$ at the infinite bond dimension on the basis of the scaling form.
description: 16 pages, 9 figures. A mistake in a finite-size scaling form corrected
Environmentally assisted cracking on titanium alloys
Creators: name: Shi, Yitong
Publisher: name: Imperial College London
Year: 2021

description: Titanium alloys have been widely used as the structural components in gas turbine engines for aerospace applications, owing to the combined benefits of the high specific strength, good corrosion resistance and excellent fatigue properties at the temperature range 300-600 °C. Failure associated with AgCl-induced HSSCC was firstly identified in 1966, on a titanium compressor disc in a spin test. However, the reaction chemistry and cracking mechanisms have been rarely studied and still remain unknown. This PhD project, sponsored by Rolls-Royce plc, aims to investigate the environmentally assisted cracking of titanium alloys, specially Ti-6246 and Ti-64. The main motivation of this study is to explore AgCl corrosion in Ti-6246, regarding the trigger conditions, reaction sequences and cracking mechanisms. Given the complex operating conditions in engines, there exist several stress/temperature windows. It is thus crucial to understand the role of each regime in the overall cracking kinetics. In addition, the fatigue crack growth behaviours and striation formation were studied in Ti-64 at different test frequencies, to examine the effect of oxygen accessibility on striation formation. Chemical analyses were performed by SEM/STEM-EDX, high resolution TEM and XRD, and oxide-Ag-oxide multilayered structures were found above and within the crack. The oxide mainly consisted of a mixture of TiO2, SnO2 and Al2O3. A proposed model of reaction sequence was established based on experimental observations and thermodynamic analysis. Hydrogen embrittlement (HE) was suggested as the possible responsible cracking mechanism, although the possibility of solid metal embrittlement (SME) could not be ruled out because of the presence of metallic Ag. With regards to the different stress/temperature windows in service, it was revealed that overall cracking rate was controlled by the HSSCC regime. However, adding extra moisture at every cold cycle of the cyclic tests was found to cause the most severe cracking with pitting, implying the occurrence of aqueous HCl attack. The fatigue crack growth rates of Ti-64 corned-cracked specimens, tested at different frequencies, were characterised by potential drop method and striation counting. The crack propagation and striation formation showed no profound dependence on the test frequency. The dislocation structures underneath the striation profiles were compared between a hollow HCF sample partially tested in vacuum and the corned-cracked specimens tested in air. There was no observation of significant change in slip activities, because the striations on the hollow sample were believed to be formed in air. Future work was suggested to complete this study.
Numerical Inside View of Hypermassive Remnant Models for GW170817
Creators: name: Kastaun, Wolfgang
name: Ohme, Frank
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The first multimessenger observation attributed to a merging neutron star binary provided an enormous amount of observational data. Unlocking the full potential of this data requires a better understanding of the merger process and the early post-merger phase, which are crucial for the later evolution that eventually leads to observable counterparts. In this work, we perform standard hydrodynamical numerical simulations of a system compatible with GW170817. We focus on a single equation of state (EOS) and two mass ratios, while neglecting magnetic fields and neutrino radiation. We then apply newly developed postprocessing and visualization techniques to the results obtained for this basic setting. The focus lies on understanding the three-dimensional structure of the remnant, most notably the fluid flow pattern, and its evolution until collapse. We investigate the evolution of mass and angular momentum distribution up to collapse, as well as the differential rotation along and perpendicular to the equatorial plane. For the cases that we studied, the remnant cannot be adequately modeled as a differentially rotating axisymetric NS. Further, the dominant aspect leading to collapse is the GW radiation and not internal redistribution of angular momentum. We relate features of the gravitational wave signal to the evolution of the merger remnant, and make the waveforms publicly available. Finally, we find that the three-dimensional vorticity field inside the disk is dominated by medium-scale perturbances and not the orbital velocity, with potential consequences for magnetic field amplification effects.
description: 20 pages, 17 figures
Understanding magnetic enhancement in hydrocarbon reservoirs
Creators: name: Osamor, Jude
Publisher: name: Imperial College London
Year: 2020

description: A detailed magnetic study has been undertaken for over 115 samples of 12 wells in the Brazeau area of the Devonian Nisku formation, Alberta Canada. I report a range of magnetic results including room temperature hysteresis, first-order reverse curve (FORCs), low-temperature magnetometry, high-temperature magnetic susceptibility results, Scanning Electron Microscopy (SEM) results of samples from sour gas pools, sweet gas and oil pools, and dry well. The sour gas pools had the strongest magnetization, followed by the sweet oil and gas pools, while the dry well had the weakest magnetization from the room temperature results. There was observable strong magnetic enhancement at the hydrocarbon fluid contact for some wells particularly the sour gas wells, while some did not have anomalies exactly at the contacts but few meters away from the contact. These anomalies are suspected to be paleo-contacts. This observable magnetic enhancement was caused by inorganic precipitation of interacting single domain hematite (0.03-0.08 μm), multidomain magnetite with a vortex (3 μm above), and SP (˂0.03 μm) greigite and pyrrhotite nanoparticle magnetic minerals at the hydrocarbon contacts. Iron oxide and sulphide minerals were revealed to be present in all the wells both from low and high-temperature measurements and also with the FORC analysis showing high coercivity ~100-350mT. From the data, iron sulphide greigite and pyrrhotite appears to be in dominant proportion alongside other minerals. I had the strong presence of siderite, greigite, and pyrite in the sour gas pools, and monoclinic pyrrhotite and maghemite in the sweet oil and gas pool and background presence of detrital magnetite, hematite, and siderite in the dry well. Authigenic magnetite and hematite were equally present in all the hydrocarbon wells. However, iron sulphide greigite and pyrrhotite appears to be in dominant proportion alongside other minerals
Bioactive composite scaffolds for bone regeneration:from the process to the biological validation
Creators: name: Ronca, Alfredo
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2010

description: In this work, we have discussed the preparation and characterization of composite scaffolds for bone regeneration. The scaffolds were made with different techniques: salt leaching / phase inversion,filament winding and stereolithography.   The phase of preparation is followed by a characterization from a morphological, mechanical and biological point of view. Results were very promising especially regarding the biological response of the substrates that appear to be promising for future  in vivo tests.
Discovery of a Ringlike Dark Matter Structure in the Core of the Galaxy Cluster Cl 0024+17
Creators: name: Jee, M. J.
name: Ford, H. C.
name: Illingworth, G. D.
name: White, R. L.
name: Broadhurst, T. J.
name: Coe, D. A.
name: Meurer, G. R.
name: Van Der Wel, A.
name: Benitez, N.
name: Blakeslee, J. P.
name: Bouwens, R. J.
name: Bradley, L. D.
name: Demarco, R.
name: Homeier, N. L.
name: Martel, A. R.
name: Mei, S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a comprehensive mass reconstruction of the rich galaxy cluster Cl 0024+17 at z~0.4 from ACS data, unifying both strong- and weak-lensing constraints. The weak-lensing signal from a dense distribution of background galaxies (~120 per square arcmin) across the cluster enables the derivation of a high-resolution parameter-free mass map. The strongly-lensed objects tightly constrain the mass structure of the cluster inner region on an absolute scale, breaking the mass-sheet degeneracy. The mass reconstruction of Cl 0024+17 obtained in such a way is remarkable. It reveals a ringlike dark matter substructure at r~75" surrounding a soft, dense core at r~50". We interpret this peculiar sub-structure as the result of a high-speed line-of-sight collision of two massive clusters 1-2 Gyr ago. Such an event is also indicated by the cluster velocity distribution. Our numerical simulation with purely collisionless particles demonstrates that such density ripples can arise by radially expanding, decelerating particles that originally comprised the pre-collision cores. Cl 0024+17 can be likened to the bullet cluster 1E0657-56, but viewed $along$ the collision axis at a much later epoch. In addition, we show that the long-standing mass discrepancy for Cl 0024+17 between X-ray and lensing can be resolved by treating the cluster X-ray emission as coming from a superposition of two X-ray systems. The cluster's unusual X-ray surface brightness profile that requires a two isothermal sphere description supports this hypothesis.
description: To appear in the June 1 issue of The Astrophysical Journal
Ligia Fabricius 1798
Creators: name: Taiti, Stefano
name: Checcucci, Ilaria
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Ligiidae
Ligia

description: Genus Ligia Fabricius, 1798 Type-species: Oniscus oceanicus Linné, 1767 by subsequent designation.
description: Published as part of Taiti, Stefano & Checcucci, Ilaria, 2009, New species and records of terrestrial Isopoda (Crustacea, Oniscidea) from Socotra Island, Yemen, pp. 73-103 in ZooKeys 31 (3) on page 78, DOI: 10.3897/zookeys.31.140, http://zenodo.org/record/576582
description: {"references": ["Fabricius JC (1798) Supplementum Entomologiae Systematicae. Proft & Storch, Hafniae, pp. 1 - 572.", "Linne C (1767) Systema Naturae per Regna tria Naturae, secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis. Editio duodecima, reformata. Regnum Animale. Tom. I. Pars II. Vol. 1. Laurentii Salvii, Holmiae, pp. 533 - 1327."]}
ASSESSMENT OF STOCHASTIC APPROXIMATION METHODS AND OF DEGENERACY DIAGNOSTIC TOOLS IN EXPONENTIAL RANDOM GRAPH MODELS
Creators: name: Stawinoga, Agnieszka
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2010

description: In recent decades there has been an enormous growth of interest in the notion of social network and the methods of Social Network Analysis (SNA). The methodology developed in the field of network analysis has been categorized into descriptive methods and statistical methods. The statistical methods may be organized into two parts; the first group consists of dyadic and triadic methods which represent statistical models for subgraphs and the second group of statistical models for entire graphs and digraphs. In this work we pay attention to the Exponential Random Graph Models (ERGMs), the statistical models which provide a general framework for modeling dependent data where the dependence can be thought of as a neighborhood effect. The present manuscript is based on two main motivations. Firstly, we are interested to examine model diagnostics and check for degeneracy of ERGMs using different methods and functions. Secondly, we aim to evaluate and compare results obtained for networks of various sizes from three different estimation procedures such as Newton-Raphson, Robbins-Monro and Stepping.
Phonon instability in two-dimensional dipolar Bose-Einstein Condensates
Creators: name: Nath, R.
name: Pedri, P.
name: Santos, L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: The partially attractive character of the dipole-dipole interaction leads to phonon instability in dipolar condensates, which is followed by collapse in three-dimensional geometries. We show that the nature of this instability is fundamentally different in two-dimensional condensates, due to the dipole-induced stabilization of two-dimensional bright solitons. As a consequence, a transient gas of attractive solitons is formed, and collapse may be avoided. In the presence of an harmonic confinement, the instability leads to transient pattern formation followed by the creation of stable two-dimensional solitons. This dynamics should be observable in on-going experiments, allowing for the creation of stable two-dimensional solitons for the first time ever in quantum gases.
description: 4 pages, 4 figures