cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Generation of directional, coherent matter beams through dynamical instabilities in Bose-Einstein condensates
Creators: name: Dennis, Graham R.
name: Johnsson, Mattias T.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present a theoretical analysis of a coupled, two-state Bose-Einstein condensate with non-equal scattering lengths, and show that dynamical instabilities can be excited. We demonstrate that these instabilities are exponentially amplified resulting in highly-directional, oppositely-propagating, coherent matter beams at specific momenta. To accomplish this we prove that the mean field of our system is periodic, and extend the standard Bogoliubov approach to consider a time-dependent, but cyclic, background. This allows us to use Floquet's theorem to gain analytic insight into such systems, rather than employing the usual Bogoliubov-de Gennes approach, which is usually limited to numerical solutions. We apply our theory to the metastable Helium atom laser experiment of Dall et al. [Phys. Rev. A 79, 011601(R) (2009)] and show it explains the anomalous beam profiles they observed. Finally we demonstrate the paired particle beams will be EPR-entangled on formation.
description: Corrected references
Automated Redistricting Simulation Using Markov Chain Monte Carlo*
Creators: name: Fifield, Benjamin
name: Higgins, Michael
name: Imai, Kosuke
name: Tarr, Alexander
Publisher: name: Taylor & Francis
Year: 2020
Subjects: subject: Space Science
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: 80699 Information Systems not elsewhere classified
subject: FOS: Computer and information sciences
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics
subject: Cancer

description: Legislative redistricting is a critical element of representative democracy. A number of political scientists have used simulation methods to sample redistricting plans under various constraints in order to assess their impact on partisanship and other aspects of representation. However, while many optimization algorithms have been proposed, surprisingly few simulation methods exist in the published scholarship. Furthermore, the standard algorithm has no theoretical justification, scales poorly, and is unable to incorporate fundamental constraints required by redistricting processes in the real world. To fill this gap, we formulate redistricting as a graph-cut problem and for the first time in the literature propose a new automated redistricting simulator based on Markov chain Monte Carlo. The proposed algorithm can incorporate contiguity and equal population constraints at the same time. We apply simulated and parallel tempering to improve the mixing of the resulting Markov chain. Through a small-scale validation study, we show that the proposed algorithm can approximate a target distribution more accurately than the standard algorithm. We also apply the proposed methodology to data from Pennsylvania to demonstrate the applicability of our algorithm to real-world redistricting problems. The open-source software package is available so that researchers and practitioners can implement the proposed methodology.
Estimating conditional quantiles with the help of the pinball loss
Creators: name: Steinwart, Ingo
name: Christmann, Andreas
Publisher: name: arXiv
Year: 2011
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics

description: The so-called pinball loss for estimating conditional quantiles is a well-known tool in both statistics and machine learning. So far, however, only little work has been done to quantify the efficiency of this tool for nonparametric approaches. We fill this gap by establishing inequalities that describe how close approximate pinball risk minimizers are to the corresponding conditional quantile. These inequalities, which hold under mild assumptions on the data-generating distribution, are then used to establish so-called variance bounds, which recently turned out to play an important role in the statistical analysis of (regularized) empirical risk minimization approaches. Finally, we use both types of inequalities to establish an oracle inequality for support vector machines that use the pinball loss. The resulting learning rates are min--max optimal under some standard regularity assumptions on the conditional quantile.
description: Published in at http://dx.doi.org/10.3150/10-BEJ267 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm)
Equivalence between non-commutative harmonic oscillators and two-photon quantum Rabi models
Creators: name: Nakahama, Ryosuke
Publisher: name: arXiv
Year: 2024
Subjects: subject: Mathematical Physics (math-ph)
subject: Classical Analysis and ODEs (math.CA)
subject: Representation Theory (math.RT)
subject: Spectral Theory (math.SP)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 81Q10, 35P05, 34M46

description: We prove that the non-commutative harmonic oscillator on $L^2(\mathbb{R})\otimes\mathbb{C}^2$ introduced by Parmeggiani and Wakayama is equivalent to the two-photon quantum Rabi model, and they are also equivalent to a holomorphic differential equation on the unit disk. The confluence process of this differential equation and the relation with the one-photon quantum Rabi model are also discussed.
description: 9 pages
Free Products and the Lack of State Preserving Approximations of Nuclear C*-algebras
Creators: name: Eckhardt, Caleb
Publisher: name: arXiv
Year: 2010
Subjects: subject: Operator Algebras (math.OA)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics

description: Let $A$ be a homogeneous C*-algebra and $ϕ$ a state on $A.$ We show that if $ϕ$ satisfies a certain faithfulness condition, then there is a net of finite-rank, unital completely positive, $ϕ$-preserving maps on $A$ that tend to the identity pointwise. This combined with results of Ricard and Xu show that the reduced free product of homogeneous C*-algebras with respect to these states have the completely contractive approximation property. We also give an example of a faithful state on $M_2\otimes C[0,1]$ for which no such state-preserving approximation of the identity map exists, thus answering a question of Ricard and Xu.
description: 9 pages
Automatic Transformation and Integration to Improve Visualization and Discovery of Latent Effects in Imaging Data
Creators: name: Hunt, Gregory J.
name: Dane, Mark A.
name: Korkola, James E.
name: Heiser, Laura M.
name: Gagnon-Bartsch, Johann A.
Publisher: name: Taylor & Francis
Year: 2020
Subjects: subject: Biochemistry
subject: Space Science
subject: Pharmacology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: 80699 Information Systems not elsewhere classified
subject: FOS: Computer and information sciences

description: Proper data transformation is an essential part of analysis. Choosing appropriate transformations for variables can enhance visualization, improve efficacy of analytical methods, and increase data interpretability. However, determining appropriate transformations of variables from high-content imaging data poses new challenges. Imaging data produce hundreds of covariates from each of thousands of images in a corpus. Each of these covariates will have a different distribution and needs a potentially different transformation. As such imaging data produce hundreds of covariates, determining an appropriate transformation for each of them is infeasible by hand. In this article, we explore simple, robust, and automatic transformations of high-content image data. A central application of our work is to microenvironment microarray bio-imaging data from the NIH LINCS program. We show that our robust transformations enhance visualization and improve the discovery of substantively relevant latent effects. These transformations enhance analysis of image features individually and also improve data integration approaches when combining together multiple features. We anticipate that the advantages of this work will likely also be realized in the analysis of data from other high-content and highly multiplexed technologies like Cell Painting or Cyclic Immunofluorescence. Software and further analysis can be found at gjhunt.github.io/rr. Supplementary materials for this article are available online.
Affixed interjections in English and Polish : a corpus-based study of emotional talk in digital communication and literary dialogue
Creators: name: Lockyer, Dorothy (Dorota)
Publisher: name: University of British Columbia
Year: 2018

description: Extensive cross-linguistic research documents a wide range of functions and semantic-pragmatic meanings of interjections in English and Polish that typically correspond with a primary function of conveying emotion. With many forms that have changed over time and appear in a variety of written and spoken mediums, interjections have been mainly considered ‘morphologically simple’; that is, they typically do not take on affixes. However, recent research has shown that interjections do, indeed, acquire various slang, diminutive and augmentative suffixes to change the register, to intensify or diminish the base interjections’ meaning, and/or to convey jocularity and non-serious meanings associated with play. This dissertation addresses some major gaps in the descriptive and empirical research of the semantic and pragmatic functions and meanings of affixed interjections in Polish, a synthetic Slavic language, and English, an analytic Germanic language. These two languages are compared and analyzed by examining the core and peripheral meanings of affixed interjections, their typology, and their pragmatic potential as attitudinals. The morphology and pragmatics of these affixed interjections are examined qualitatively and quantitatively by examining definitions from online dictionaries and standard corpora. It is argued that three fundamental semantic constraints underlie the formation of affixed interjections: [+INFORMAL], [+EMOTION], and [+ATTITUDE]. These three features can be subdivided into secondary semantic and pragmatic features that may or may not always apply, including [+PLAYFUL], [+CUTE], [+SILLY], [+GOOD HUMOUR], [+INTIMATE] and [+WARM]. Given the volume and variety of forms considered, affixed interjections would be methodologically challenging to gather in naturally occurring spontaneous speech; therefore, the study combines data from corpora of online sources that provide novel, current and slang words, including the micro-blogging site Twitter, Google Books, fanfiction, blogs, and blog comments. The dissertation also examines the Appraisal resources (Martin and White 2005) used for diminutive interjections. It is argued that English uses diminutive interjections mainly for positive APPRECIATION (positive meanings), negative JUDGEMENT (sarcasm), and negative AFFECT (negative meanings). These interjections are relatively rare compared to Polish. In comparison, Polish diminutives are much more frequent and conventional, and are used to facilitate social bonding, and show warmth and affection.
High-energy Neutrino Source Cross-correlations with Nearest-neighbor Distributions
Creators: name: Zhou, Zhuoyang
name: Cisewski-Kehe, Jessi
name: Fang, Ke
name: Banerjee, Arka
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Applications (stat.AP)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: The astrophysical origins of the majority of the IceCube neutrinos remain unknown. Effectively characterizing the spatial distribution of the neutrino samples and associating the events with astrophysical source catalogs can be challenging given the large atmospheric neutrino background and underlying non-Gaussian spatial features in the neutrino and source samples. In this paper, we investigate a framework for identifying and statistically evaluating the cross-correlations between IceCube data and an astrophysical source catalog based on the $k$-nearest-neighbor cumulative distribution functions ($k$NN-CDFs). We propose a maximum likelihood estimation procedure for inferring the true proportions of astrophysical neutrinos in the point-source data. We conduct a statistical power analysis of an associated likelihood ratio test with estimations of its sensitivity and discovery potential with synthetic neutrino data samples and a WISE-2MASS galaxy sample. We apply the method to IceCube's public ten-year point-source data and find no statistically significant evidence for spatial cross-correlations with the selected galaxy sample. We discuss possible extensions to the current method and explore the method's potential to identify the cross-correlation signals in data sets with different sample sizes.
description: 14 pages, 11 figures, 1 appendix
Chiral condensate and dressed Polyakov loop in the Nambu--Jona-Lasinio model
Creators: name: Mukherjee, Tamal K.
name: Chen, Huan
name: Huang, Mei
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We investigate the chiral condensate and the dressed Polyakov loop or dual chiral condensate at finite temperature and density in two-flavor Nambu--Jona-Lasinio model. The dressed Polyakov loop is regarded as an equivalent order parameter of deconfinement phase transition in a confining theory. We find the behavior of dressed Polyakov loop in absence of any confinement mechanism is quite interesting, with only quark degrees of freedom present, it still shows an order parameter like behavior. It is found that in the chiral limit, the critical temperature for chiral phase transition coincides with that of the dressed Polyakov loop in the whole $(T,μ)$ plane. In the case of explicit chiral symmetry breaking, it is found that the transition temperature for chiral restoration $T_c^χ$ is smaller than that of the dressed Polyakov loop $T_c^{\cal D}$ in the low baryon density region where the transition is a crossover. With the increase of current quark mass the difference between the two transition temperatures is found to be increasing. However, the two critical temperatures coincide in the high baryon density region where the phase transition is of first order. We give an explanation on the feature of $T_c^χ=T_c^{\cal D}$ in the case of 1st and 2nd order phase transitions, and $T_c^χ
description: 7 pages, 10 figures
Variation of jet quenching from RHIC to LHC and thermal suppression of QCD coupling constant
Creators: name: Zakharov, B. G.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We perform a joint jet tomographic analysis of the data on the nuclear modification factor $R_{AA}$ from PHENIX at RHIC and ALICE at LHC. The computations are performed accounting for radiative and collisional parton energy loss with running coupling constant. Our results show that the observed slow variation of $R_{AA}$ from RHIC to LHC indicates that the QCD coupling constant is suppressed in the quark-gluon plasma produced at LHC.
description: 9 pages, 2 figures
Art about life form encounters : making sense of place in the Okanagan region
Creators: name: Yamamoto, Megumi
Publisher: name: University of British Columbia
Year: 2018

description: My research explores how creating art can be a method of connecting to an unfamiliar environment. Positioning myself as a newcomer to the Okanagan, I observe, document, and work with the various life forms I encounter in Kelowna over a two-year time period to demonstrate how through creating art, a sense of place and an appreciation for a place can arise over time in an individual’s mind. In the creative research, I ask the following questions: How can creating visual art about a local natural environment develop a newcomer’s sense of place? And how might creating art about the experience of a place enhance or facilitate the development of one’s connection to a place and sense of belonging? Informed by hermeneutic phenomenology and working in various mediums, I use observation and interaction as forms of lived experience and art making as a method of generating meaning and knowledge. My artwork isolates and seeks to identify the individual life forms I encounter in Kelowna in order to deconstructing the environment – a complex interconnected system – to acquaint myself with the land, resulting in a body of work presenting a construction of my perspectival experience. Giving significance to the commonplace and easily overlooked aspects of nature as important place-defining elements within the urban environment (my everyday-surroundings), I hope to encourage viewers to reflect on their own perceptions of place and to consider the significance that life forms have in shaping the way in which a place is perceived. My work engages with the ideas put forward by Jakob von Uexküll, Elen-Maarja Trell and Bettina van Hoven, Rachel D. Kroencke, Nina Katchadourian, Lynette Shultz, Megan K. Halpern and Hannah Star Rogers, Joseph Cornell, Walter Benjamin, and Giles Deleuze and Felix Guattari.
cosmICweb: Cosmological Initial Conditions for Zoom-in Simulations in the Cloud
Creators: name: Buehlmann, Michael
name: Winkler, Lukas
name: Hahn, Oliver
name: Helly, John C.
name: Jenkins, Adrian
Publisher: name: arXiv
Year: 2024
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the online service cosmICweb (COSMological Initial Conditions on the WEB) - the first database and web interface to store, analyze, and disseminate initial conditions for zoom simulations of objects forming in cosmological simulations: from galaxy clusters to galaxies and more. Specifically, we store compressed information about the Lagrangian proto-halo patches for all objects in a typical simulation merger tree along with properties of the halo/galaxy across cosmic time. This enables a convenient web-based selection of the desired zoom region for an object fitting user-specified selection criteria. The information about the region can then be used with the MUSIC code to generate the zoom ICs for the simulation. In addition to some other simulations, we currently support all objects in the EAGLE simulation database, so that for example the Auriga simulations are easily reproduced, which we demonstrate explicitly. The framework is extensible to include other simulations through an API that can be added to an existing database structure and with which cosmICweb can then be interfaced. We make the web portal and database publicly available to the community.
description: Accepted in The Open Journal of Astrophysics. The cosmICweb portal is accessible under https://cosmicweb.eu. v2: fixed rendering issues (Safari) in Fig. 3 v3: addressed referee comments
Fourier transforms of orbital integrals on the Lie algebra of $\operatorname{SL}_2$
Creators: name: Spice, Loren
Publisher: name: arXiv
Year: 2010
Subjects: subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 22E50, 22E35

description: The Harish-Chandra--Howe local character expansion expresses the characters of reductive, $p$-adic groups in terms of Fourier transforms of nilpotent orbital integrals on their Lie algebras, and Murnaghan--Kirillov theory expresses many characters of reductive, $p$-adic groups in terms of Fourier transforms of semisimple orbital integrals (also on their Lie algebras). In many cases, the evaluation of these Fourier transforms seems intractable; but, for $\operatorname{SL}_2$, the nilpotent orbital integrals have already been computed. In this paper, we use a variant of Huntsinger's integral formula, and the theory of $p$-adic special functions, to compute semisimple orbital integrals.
description: 35 pages; v2: updated introduction to refer to work of Langlands
32119: The lockdown routine
Creators: name: Project, Lockdown2020 and Beyond
Publisher: name: University of Oxford
Year: 2023
Subjects: classificationCode: 479999
subject: Other language, communication and culture not elsewhere classified

description: As an international couple, we have taken the lockdown opportunity to spend more (than ever) time together, while adjusting our work routines, inside the same flat. I have transformed the living room in a double-use space, where I now have a fully functional working place. He has taken the office as his composing cave and recording studio. We wake up early with the sounds of the birds or the cat meowing for food. He gets up, plays with the cat for 15 minutes and meditates for 20 min. During this time, I shamelessly check for new e-mails and social media notifications. We prepare breakfast and sip on our coffee while we observe a recurrent squirrel cross the electricity cables in front of our kitchen window. We hear the cat nibbling the food and we smile. Time for family breakfast is precious. We remind ourselves of which video calls we have that day and make plans to switch off internet to not overload the WIFI. We take our left-over coffee and march to our offices to start the work day. Two hours later we have a break for a coffee refill, and if no urgent seminars are due, we sit in the sofa and discuss the hot topic of the day. Occasionally the break will consist of a scream to get rid of a multi-legged uninvited creepy crawler. We return to our work desks - which now I recall being an ironing table the first week of lockdown -, and work for another 2-3h. Most of the times he cooks and calls me for having a quick meal while watching the newly arrived YouTube video of our favourite channel. We return to our work desks and, sometime in the middle the afternoon, he wants to show me his latest composition progress. I always smile. I understand little, but continue to smile in a motivating manner while picturing mentally the process of transforming the sounds of hitting stones into programming lines which then make music. Other times, I speak out loud about my hypothetical science project ideas and see how much of that he understands. This helps me keeping things objective and simple. Before continuing to work, we discuss at what time he goes for a walk and if I join that day. We decide I will go on the weekend and tell him we can get flowers to bring colour to the kitchen. After a long work day, later in the evening, we discuss the unfortunate things this confinement is bringing upon our career development, while we think about the privilege of spending time together at home, protected and protecting others. How (too) soon this will end and he will leave again.
Undulation Instability of Epithelial Tissues
Creators: name: Basan, Markus
name: Joanny, Jean-Francois
name: Prost, Jacques
name: Risler, Thomas
Publisher: name: arXiv
Year: 2011
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Fluid Dynamics (physics.flu-dyn)
subject: Medical Physics (physics.med-ph)
subject: Tissues and Organs (q-bio.TO)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Treating the epithelium as an incompressible fluid adjacent to a viscoelastic stroma, we find a novel hydrodynamic instability that leads to the formation of protrusions of the epithelium into the stroma. This instability is a candidate for epithelial fingering observed in vivo. It occurs for sufficiently large viscosity, cell-division rate and thickness of the dividing region in the epithelium. Our work provides physical insight into a potential mechanism by which interfaces between epithelia and stromas undulate, and potentially by which tissue dysplasia leads to cancerous invasion.
description: 4 pages, 3 figures
Coaddition Artifact Rejection and CompareWarp
Creators: name: AlSayyad, Yusra
Publisher: name: Zenodo
Year: 2018
Subjects: lsst

description: LSST images will be contaminated with transient artifacts, such as optical ghosts, satellite trails, and cosmic rays, and with transient astronomical sources, such as asteroid ephemerides. We developed and tested an algorithm to find and reject these artifacts during coaddition, in order to produce clean coadds to be used for deep detection and preliminary object characterization. This algorithm, CompareWarpAssembleCoadduses the time-series of PSF-matched warped images to identify transient artifacts. It detects artifact candidates on the image differences between each PSF-matched warp and a static sky model. These artifact candidates include both true transient artifacts and difference-image false positives such as difficult-subtract-sources and variable sources such as stars and quasars. We use the feature that true transients appear at a given position in the difference images in only a small fraction (configurable) of visits, whereas variable sources and difficult-to-subtract sources appear in most difference images. In this report, we present a description of the method and an evaluation using Hyper SuprimeCam PDR1 data.
Emergence of topological states in relaxation dynamics of interacting bosons
Creators: name: Huang, Wang
name: Yang, Xu-Chen
name: Cao, Rui
name: Wu, Ying-Hai
name: Yuan, Jianmin
name: Li, Yongqiang
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Topological concepts have been employed to understand the ground states of many strongly correlated systems, but it is still quite unclear if and how topology manifests itself in the relaxation dynamics. Here we uncover emergent topological phenomena in the time evolution of far-from-equilibrium one-dimensional interacting bosons. Beginning with simple product states, the system evolves into long-time stationary states with high energy that are nonthermal for a wide range of parameters, and they exhibit nonlocal string correlation that is characteristic of the symmetry-protected topological ground state of the Hamiltonian. In contrast, no topological feature is found in the stationary state as long as the system thermalizes. This difference is further corroborated by the distinct behaviour of quantum entanglement and edge states of the system. Our theoretical prediction can be examined by current experimental techniques and paves the way for a more comprehensive understanding of topological phases in nonequilibrium settings.
description: 7 pages, 4 figures, with supplymentary information. This paper has been accepted for publication in Physical Review Letters
Electron Confinement, Orbital Ordering, and Orbital Moments in $d^0$-$d^1$ Oxide Heterostructures
Creators: name: Pardo, Victor
name: Pickett, Warren E.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The (SrTiO$_3$)$_m$/(SrVO$_3$)$_n$ $d^0-d^1$ multilayer system is studied with first principles methods through the observed insulator-to-metal transition with increasing thickness of the SrVO$_3$ layer. When correlation effects with reasonable magnitude are included, crystal field splittings from the structural relaxations together with spin-orbit coupling (SOC) determines the behavior of the electronic and magnetic structures. These confined slabs of SrVO$_3$ prefer $Q_{orb}$=($π,π$) orbital ordering of $\ell_z = 0$ and $\ell_z = -1$ ($j_z=-1/2$) orbitals within the plane, accompanied by $Q_{spin}$=(0,0) spin order (ferromagnetic alignment). The result is a SOC-driven ferromagnetic Mott insulator. The orbital moment of 0.75 $μ_B$ strongly compensates the spin moment on the $\ell_z = -1$ sublattice. The insulator-metal transition for $n = 1 \to 5$ (occurring between $n$=4 and $n$=5) is reproduced. Unlike in the isoelectronic $d^0-d^1$ TiO$_2$/VO$_2$ (rutile structure) system and in spite of some similarities in orbital ordering, no semi-Dirac point [{\it Phys. Rev. Lett.} {\bf 102}, 166803 (2009)] is encountered, but the insulator-to-metal transition occurs through a different type of unusual phase. For n=5 this system is very near (or at) a unique semimetallic state in which the Fermi energy is topologically determined and the Fermi surface consists of identical electron and hole Fermi circles centered at $k$=0. The dispersion consists of what can be regarded as a continuum of radially-directed Dirac points, forming a "Dirac circle".
description: 9 pages, 8 figures
A comprehensive approach to incorporating intermolecular dispersion into the openCOSMO-RS model. Part 1: Halocarbons
Creators: name: Grigorash, Daria
name: Müller, Simon
name: Paricaud, Patrice
name: Stenby, Erling H.
name: Smirnova, Irina
name: Yan, Wei
Publisher: name: arXiv
Year: 2024
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The COSMO-RS (Conductor-like Screening Model for Real Solvents) is a predictive thermodynamic model that has found diverse applications in various domains like chemical engineering, environmental chemistry, nanotechnology, material science, and biotechnology. Its core concept involves calculating the screening charge density on the surface of each molecule and letting these surface patches interact with each other to calculate thermodynamic properties. In this study, we aim to enhance the performance of the open-source implementation openCOSMO-RS by incorporating dispersive interactions between the paired segments. Several parametrizations were systematically evaluated through the extensive regression analysis using a comprehensive database of Vapor-Liquid Equilibrium (VLE), Liquid-Liquid Equilibrium (LLE) and Infinite Dilution Activity Coefficients (IDACs). Furthermore, the influence of different combinatorial terms on the model performance was investigated. Our findings indicate that incorporating dispersive interactions significantly improves the accuracy of phase equilibrium predictions for halocarbons and refrigerant mixtures.
Orbital Migration Models under Test
Creators: name: Kley, Willy
Publisher: name: arXiv
Year: 2011
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Planet-disk interaction predicts a change in the orbital elements of an embedded planet. Through linear and fully hydrodynamical studies it has been found that migration is typically directed inwards. Hence, this migration process gives natural explanation for the presence of the 'hot' planets orbiting close to the parent star, and it plays a mayor role in explaining the formation of resonant planetary systems. However, standard migration models for locally isothermal disks indicate a too rapid inward migration for small mass planets, and a large number of massive planets are found very far away from the star. Recent studies, including more complete disk physics, have opened up new paths to slow down or even reverse migration. The new findings on migration are discussed and connected to the observational properties of planetary systems.
description: 8 pages, Review talk at IAU Symposium 276, to appear in: The Astrophysics of Planetary Systems, Eds.A.Sozzetti, M.G.Lattanzi & A.P.Boss
Observables in non-Hermitian systems: A methodological comparison
Creators: name: Sim, Karin
name: Defenu, Nicolò
name: Molignini, Paolo
name: Chitra, R.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Despite acute interest in the dynamics of non-Hermitian systems, there is a lack of consensus in the mathematical formulation of non-Hermitian quantum mechanics in the community. Different methodologies are used in the literature to study non-Hermitian dynamics. This ranges from consistent frameworks like biorthogonal quantum mechanics and metric approach characterized by modified inner products, to normalization by time-dependent norms inspired by open quantum systems. In this work, we systematically explore the similarities and differences among these various methods. Utilizing illustrative models with exact solutions, we demonstrate that these methods produce not only quantitatively different results but also distinct physical interpretations. For dissipative systems where non-Hermiticity arises as an approximation, we find that simply dividing by the norm in the $\mathcal{PT}$-broken regime closely aligns with the full master equation solutions. In contrast, for quantum systems where non-Hermiticity can be engineered exactly, incorporating metric dynamics is crucial for the probabilistic interpretation of quantum mechanics, necessitating the generalizations of similarity transformations and unitarity to non-Hermitian systems. This study lays the groundwork for further exploration of non-Hermitian Hamiltonians, potentially leveraging generalized transformations for novel physical phenomena.
description: 11 pages, 2 figures, 1 table
The effect of local thermal fluctuations on the folding kinetics: a study from the perspective of the nonextensive statistical mechanics
Creators: name: Molin, J. P. Dal
name: da Silva, M. A. A.
name: Caliri, A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences
subject: 82

description: Protein folding is a universal process, very fast and accurate, which works consistently (as it should be) in a wide range of physiological conditions. The present work is based on three premises, namely: ($i$) folding reaction is a process with two consecutive and independent stages, namely the search mechanism and the overall productive stabilization; ($ii$) the folding kinetics results from a mechanism as fast as can be; and ($iii$) at nanoscale dimensions, local thermal fluctuations may have important role on the folding kinetics. Here the first stage of folding process (search mechanism) is focused exclusively. The effects and consequences of local thermal fluctuations on the configurational kinetics, treated here in the context of non extensive statistical mechanics, is analyzed in detail through the dependence of the characteristic time of folding ($τ$) on the temperature $T$ and on the nonextensive parameter $q$.The model used consists of effective residues forming a chain of 27 beads, which occupy different sites of a $3-$D infinite lattice, representing a single protein chain in solution. The configurational evolution, treated by Monte Carlo simulation, is driven mainly by the change in free energy of transfer between consecutive configurations. ...
description: 19 pages, 3 figures, 1 table
Low lysosomal acid lipase activity in smooth muscle cells relative to macrophages provides new insights into foam cell formation in atherosclerosis
Creators: name: Dubland, Joshua Andrew
Publisher: name: University of British Columbia
Year: 2018

description: Smooth muscle cells (SMCs) are the predominant cell type in the intima of human atherosclerosis-prone arteries and promote initial retention of atherogenic lipoproteins in the deep intima. We previously found that ≥50% of foam cells in intermediate coronary atheromas are of SMC origin and that intimal SMCs have reduced expression of the cholesterol exporter protein ATP-binding cassette transporter A1 (ABCA1). ABCA1 expression is dependent on the flux of cholesterol out of lysosomes, generated via the hydrolysis of lipoprotein-derived cholesteryl esters (CEs) to cholesterol by lysosomal acid lipase (LAL), and subsequent generation of oxysterols such as 27-hydroxycholesterol by CYP27A1 for promotion of gene transcription via the nuclear liver X receptor (LXR). In the present studies we tested the hypothesis that SMCs have reduced lysosomal function that contributes to foam cell formation. Chapter 2 investigates and defines the role of lysosomal function in cholesterol metabolism using a mouse LAL KO peritoneal macrophage model. Chapter 3 investigates lysosomal function and cholesterol metabolism differences between human monocyte-derived macrophages (HMMs) and arterial SMCs treated with aggregated LDL (agLDL). Unlike HMMs, lipid loading of SMCs did not significantly increase 27-hydroxycholesterol or ABCA1 levels and did not decrease new cholesterol synthesis. Microscopy revealed sequestration of CEs in lysosomes of SMCs, while HMMs displayed mostly cytosolic CE accumulations. We did not find evidence of a lysosomal functional defect from lipid induced loss of acidity or loss of lysosomal proteolytic function in SMCs. Instead, LAL levels were markedly higher in macrophages compared to SMCs (LAL activity 23.4-times higher in agLDL loaded HMMs compared to SMCs, p<0.001). Treatment of SMCs with LAL containing medium decreased lysosomal lipid accumulation, decreased new cholesterol synthesis, and increased cholesterol efflux. Persistent reduction of ABCA1 response to LAL treatment in SMCs was potentially attributable to low CYP27A1 and LXR expression relative to macrophages. Overall, we find that arterial SMCs have a relative deficiency in LAL and associated defects in downstream sterol regulatory events compared to macrophages. Our results indicate low LAL activity in SMCs as a novel reason for foam cell formation and a potential target to reduce atherosclerosis development and promote regression therapeutically.
Coupled-channel analysis of the X(3872)
Creators: name: Coito, S.
name: Rupp, G.
name: van Beveren, E.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The X(3872) is studied as an axial-vector charmonium state in the multichannel framework of the Resonance-Spectrum-Expansion quark-meson model, previously applied to a variety of other puzzling mesonic resonances. Included are the open-charm pseudoscalar-vector and vector-vector channels, the most important of which is the S-wave $\bar{D}^{*0}D^{0}$ + $D^{*0}\bar{D}^{0}$ channel, which practically coincides with the X(3872) structure. The two free parameters of the model are tuned so as to roughly reproduce the $χ_{c1}(3511)$ mass as well as the enhancement just above the $\bar{D}^{*0}D^{0}$ / $D^{*0}\bar{D}^{0}$ threshold. The present model is able to describe the shape of the latter data quite well. However, as no dynamical resonance pole is found, the X(3872) and X(3940) cannot be reproduced simultaneously, at this stage. A possible further improvement is discussed.
description: 6 pages, 3 figures, Acta Physica Polonica B style; plenary talk given by Susana Coito at the workshop Excited QCD 2010, 31 Jan. - 6 Feb. 2010 in Stara Lesna, Slovakia
Small orders of Hadamard matrices and base sequences
Creators: name: Djokovic, Dragomir Z.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05B20, 05B30

description: We update the list of odd integers n<10000 for which an Hadamard matrix of order 4n is known to exist. We also exhibit the first example of base sequences BS(40,39). Consequently, there exist T-sequences TS(n) of length n=79. The first undecided case has the length n=97.
description: 7 pages
Highly entangled stationary states from strong symmetries
Creators: name: Li, Yahui
name: Pollmann, Frank
name: Read, Nicholas
name: Sala, Pablo
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We find that the presence of strong non-Abelian conserved quantities can lead to highly entangled stationary states even for unital quantum channels. We derive exact expressions for the bipartite logarithmic negativity, Rényi negativities, and operator space entanglement for stationary states restricted to one symmetric subspace, with focus on the trivial subspace. We prove that these apply to open quantum evolutions whose commutants, characterizing all strongly conserved quantities, correspond to either the universal enveloping algebra of a Lie algebra or to the Read-Saleur commutants. The latter provides an example of quantum fragmentation, whose dimension is exponentially large in system size. We find a general upper bound for all these quantities given by the logarithm of the dimension of the commutant on the smaller bipartition of the chain. As Abelian examples, we show that strong U($1$) symmetries and classical fragmentation lead to separable stationary states in any symmetric subspace. In contrast, for non-Abelian SU$(N)$ symmetries, both logarithmic and Rényi negativities scale logarithmically with system size. Finally, we prove that while Rényi negativities with $n>2$ scale logarithmically with system size, the logarithmic negativity (as well as generalized Rényi negativities with $n<2$) exhibits a volume law scaling for the Read-Saleur commutants. Our derivations rely on the commutant possessing a Hopf algebra structure in the limit of infinitely large systems, and hence also apply to finite groups and quantum groups.
description: Published version
Scaling dimensions in hidden Kerr/CFT
Creators: name: Lowe, David A.
name: Messamah, Ilies
name: Skanata, Antun
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: It has been proposed that a hidden conformal field theory (CFT) governs the dynamics of low frequency scattering in a general Kerr black hole background. We further investigate this correspondence by mapping higher order corrections to the massless wave equations in a Kerr background to an expansion within the CFT in terms of higher dimension operators. This implies the presence of infinite towers of CFT primary operators with positive conformal dimensions compatible with unitarity. The exact Kerr background softly breaks the conformal symmetry and the scaling dimensions of these operators run with frequency. The scale-invariant fixed point is dual to a degenerate case of flat spacetime.
description: 13 pages
A high-flux cold-atom source utilising a grating atom chip
Creators: name: Heine, Hendrik
name: Gonidec, Melanie S Le
name: Arnold, Aidan S
name: Griffin, Paul F
name: Riis, Erling
name: Herr, Waldemar
name: Rasel, Ernst M
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Bose-Einstein condensates (BECs) have been proposed for many applications in atom interferometry, as their coherence over long evolution times promises unprecedented sensitivity. To date, BECs can be efficiently created in devices using atom chips, but these are still complex and place high demands on size, weight and power. To further simplify these setups, we equipped an atom chip with a nano-structured diffraction-grating to derive all beams for the magneto-optical trap (MOT) from a single laser beam. Moreover, using a 2D$^+$-MOT as an atomic source and a beam with uniform intensity for the grating illumination, we capture $1\times10^9$ atoms in one second, cool them to $14\,μ$K, and demonstrate magnetic trapping using the atom chip. This is a major step towards the simplification of portable BEC devices for quantum sensing on earth and in space.
description: 12 pages, 3 figures
Revista Portuguesa de Investigação Educacional, n. 21 (2021)
Creators: name: Revista Portuguesa De Investigação Educacional
Publisher: name: Revista Portuguesa de Investigação Educacional
Year: 2021

description: Ensino e aprendizagem a distância – desafios e oportunidades para estudantes com necessidades educativas especiais...1-13 O uso da robótica na intervenção com crianças com autismo em macau: um estudo exploratório com o milo...1-26 Ensino remoto de emergência em tempos de pandemia: a experiência de professores portugueses...1-26 Influência de aspetos socioculturais e domésticos na aprendizagem online em países em desenvolvimento...1-19 Digital skills of young people at the time of entry into university...1-22 O PISA e a literacia financeira: os resultados de Portugal...1-20 Escola no estabelecimento prisional de Aveiro: uma oportunidade ainda mais comprometida em tempo de pandemia de COVID-19...1-42
title: Machine Learning and Data Mining in Complex Genomics Big Data: Developing Efficient Tools to Advance Computational Systems Biology
Creators: name: Duhan, Naveen
Publisher: name: Utah State University
Year: 2024

description: In agriculture, multi-omics can aid in addressing the growing demand for food amidst an increasing global population. One area of agricultural research that is particularly important is plant-microbe interactions. Plants and microbes interact in many ways, some beneficial to plants, helping them grow and thrive. Other microbes can be harmful, causing diseases. Understanding these interactions could help us to develop disease-resilient crops. One of the most important technologies in genomics is Next-Generation Sequencing (NGS). NGS allows us to sequence DNA and RNA quickly and study complex biological mechanisms on a genome-wide scale and across different species. The cost of sequencing is decreasing rapidly, and we are now generating enormous amounts of sequence data. However, analyzing this data remains a challenge. We developed tools to assist researchers in analyzing complex biological data on plant-microbe interactions, enabling a deeper understanding of the relationships between plants and microbes. Researchers can use these tools to analyze gene expression, identify microRNAs and enzymes, and predict the location of proteins in the cells. In addition to these tools, we also developed a user-friendly comprehensive database of protein-protein interactions between cereal crops and microbes, facilitating the study of plant-microbe interactions. The tools and databases developed in this project will serve as valuable resources for the biological research community. By offering deeper insights into plant-microbe interactions, these tools will support researchers in advancing future crop improvement efforts.
Casimir effect of electromagnetic field in Randall-Sundrum spacetime
Creators: name: Teo, L. P.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the finite temperature Casimir effect on a pair of parallel perfectly conducting plates in Randall-Sundrum model without using scalar field analogy. Two different ways of interpreting perfectly conducting conditions are discussed. The conventional way that uses perfectly conducting condition induced from 5D leads to three discrete mode corrections. This is very different from the result obtained from imposing 4D perfectly conducting conditions on the 4D massless and massive vector fields obtained by decomposing the 5D electromagnetic field. The latter only contains two discrete mode corrections, but it has a continuum mode correction that depends on the thicknesses of the plates. It is shown that under both boundary conditions, the corrections to the Casimir force make the Casimir force more attractive. The correction under 4D perfectly conducting condition is always smaller than the correction under the 5D induced perfectly conducting condition. These statements are true at any temperature.
description: 20 pages, 4 figures