cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Additional file 4 of Stillbirth outcome capture and classification in population-based surveys: EN-INDEPTH study
Creators: name: Blencowe, Hannah
name: Bottecchia, Matteo
name: Kwesiga, Doris
name: Akuze, Joseph
name: M. Moinuddin Haider
name: Galiwango, Edward
name: Dzabeng, Francis
name: Fisker, Ane B.
name: Yeetey Akpe Kwesi Enuameh
name: Bisrat Misganaw Geremew
name: Tryphena Nareeba
name: Woodd, Susannah
name: Beedle, Alexandra
name: Peven, Kimberly
name: Cousens, Simon
name: Waiswa, Peter
name: Lawn, Joy E.
Publisher: name: figshare
Year: 2021
Subjects: subject: Medicine
subject: Cell Biology
subject: Biotechnology
subject: Ecology
subject: FOS: Biological sciences
subject: Sociology
subject: FOS: Sociology
subject: Cancer
subject: 110309 Infectious Diseases
subject: FOS: Health sciences

description: Additional file 4. Ethical approval of local Institutional Review Boards.
Hybrid star phenomenology from the properties of the special point
Creators: name: Gärtlein, Christoph
name: Ivanytskyi, Oleksii
name: Sagun, Violetta
name: Blaschke, David
Publisher: name: arXiv
Year: 2023
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the properties of hybrid stars containing a color superconducting quark matter phase in their cores, which is described by the chirally symmetric formulation of the confining relativistic density functional approach. It is shown that depending on the dimensionless vector and diquark couplings of quark matter, the characteristics of the deconfinement phase transition are varied, allowing us to study the relation between those characteristics and mass-radius relations of hybrid stars. Moreover, we show that the quark matter equation of state (EoS) can be nicely fitted by the Alford-Braby-Paris-Reddy model that gives a simple functional dependence between the most important parameters of the EoS and microscopic parameters of the initial Lagrangian. Based on it, we analyze the special points of the mass-radius diagram in which several mass-radius curves intersect. Using the found empirical relation between the mass of the special point, the maximum mass of the mass-radius curve, and the onset mass of quark deconfinement, we constrain the range of values of the vector and diquark couplings of the quark matter model. With this constraint, we construct a family of mass-radius curves, which allow us to describe the black widow pulsar PSR J0952-0607 with a mass of $2.35\pm 0.17~\rm M_\odot$ as a hybrid star with a color superconducting quark matter core.
description: 13 pages, 8 figures, 4 tables, accepted for publication in Physical Review D
Ratchet Swap Valuation
Creators: name: Lee, David
Publisher: name: Zenodo
Year: 2022
Subjects: Ratchet Swap Valuation

description: A ratchet swap is an interest rate swap with two legs. One leg is a standard floating leg and the other leg is a ratchet leg. The ratchet leg pays a ratchet floating rate. The ratchet floating rate coupon is based on an index, e.g., 6-month EURIBOR. The rate is further subject to a minimum decrease of 0 bps and a maximum increase of a threshold, such as, 15 bps. These rates are reset two business days prior to the first day of each coupon period.
description: https://osf.io/azy78/download
Making a tournament indecomposable by one subtournament-reversal operation
Creators: name: Belkhechine, Houmem
name: Salha, Cherifa Ben
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C20, 05C35

description: Given a tournament $T$, a module of $T$ is a subset $M$ of $V(T)$ such that for $x, y\in M$ and $v\in V(T)\setminus M$, $(v,x)\in A(T)$ if and only if $(v,y)\in A(T)$. The trivial modules of $T$ are $\emptyset$, $\{u\}$ $(u\in V(T))$ and $V(T)$. The tournament $T$ is indecomposable if all its modules are trivial; otherwise it is decomposable. Let $T$ be a tournament with at least five vertices. In a previous paper, the authors proved that the smallest number $δ(T)$ of arcs that must be reversed to make $T$ indecomposable satisfies $δ(T) \leq \left\lceil \frac{v(T)+1}{4} \right\rceil$, and this bound is sharp, where $v(T) = |V(T)|$ is the order of $T$. In this paper, we prove that if the tournament $T$ is not transitive of even order, then $T$ can be made indecomposable by reversing the arcs of a subtournament of $T$. We denote by $δ'(T)$ the smallest size of such a subtournament. We also prove that $δ(T) = \left\lceil \frac{δ'(T)}{2} \right\rceil$.
description: 15 pages
Radiative and interelectronic-interaction corrections to the hyperfine splitting in highly charged B-like ions
Creators: name: Oreshkina, N. S.
name: Glazov, D. A.
name: Volotka, A. V.
name: Shabaev, V. M.
name: Tupitsyn, I. I.
name: Plunien, G.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The ground-state hyperfine splitting values of high-Z boronlike ions are calculated. Calculation of the interelectronic-interaction contribution is based on a combination of the 1/Z perturbation theory and the large-scale configuration-interaction Dirac-Fock-Sturm method. The screened QED corrections are evaluated utilizing an effective screening potential approach. Total hyperfine splitting energies are presented for several B-like ions of particular interest: {}^{45}Sc{}^{16+}, {}^{57}Fe{}^{21+}, {}^{207}Pb{}^{77+}, and {}^{209}Bi{}^{78+}. For lead and bismuth the experimental values of the 1s hyperfine splitting are employed to improve significantly the theoretical results by reducing the uncertainty due to the nuclear effects.
description: 12 pages, 2 figures, 3 tables
Needlet algorithms for estimation in inverse problems
Creators: name: Kerkyacharian, Gérard
name: Petrushev, Pencho
name: Picard, Dominique
name: Willer, Thomas
Publisher: name: arXiv
Year: 2007
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62G05, 62G20 (Primary) 65J20 (Secondary)

description: We provide a new algorithm for the treatment of inverse problems which combines the traditional SVD inversion with an appropriate thresholding technique in a well chosen new basis. Our goal is to devise an inversion procedure which has the advantages of localization and multiscale analysis of wavelet representations without losing the stability and computability of the SVD decompositions. To this end we utilize the construction of localized frames (termed "needlets") built upon the SVD bases. We consider two different situations: the "wavelet" scenario, where the needlets are assumed to behave similarly to true wavelets, and the "Jacobi-type" scenario, where we assume that the properties of the frame truly depend on the SVD basis at hand (hence on the operator). To illustrate each situation, we apply the estimation algorithm respectively to the deconvolution problem and to the Wicksell problem. In the latter case, where the SVD basis is a Jacobi polynomial basis, we show that our scheme is capable of achieving rates of convergence which are optimal in the $L_2$ case, we obtain interesting rates of convergence for other $L_p$ norms which are new (to the best of our knowledge) in the literature, and we also give a simulation study showing that the NEED-D estimator outperforms other standard algorithms in almost all situations.
description: Published at http://dx.doi.org/10.1214/07-EJS014 in the Electronic Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Eyewitness’ characteristics and memory : an in situ analysis
Creators: name: Cutshall, Judith Lynne
Publisher: name: University of British Columbia
Year: 2010

description: An extensive review of eyewitness testimony research reveals that (1) research findings are inconsistent in their assessments of the fallibility of eyewitness memory and in their attempts to delineate the factors which affect eyewitness' memory; (2) the criminal justice system questions the validity of generalizing these research findings to real-world eyewitnessing situations. It is suggested in this thesis that researchers' over-reliance on experimental methodology has led to a confused image of eyewitness' memory which is of questionable relevance to actual eyewitness situations. A non-experimental examination of real-world eyewitnesses is therefore proposed as a first step toward collecting meaningful data relating to eyewitness memory. Two types of non-experimental research are presented in this thesis: archival research and a case study of eyewitnesses to a violent crime. The archival research, which was drawn from R.C.M. Police files, was designed as a means of gathering baseline data concerning actual eyewitnesses, for example, their gender and age and how often they are also victims of crime. The case study involved interviewing thirteen witnesses, all of whom had witnessed the same gunshooting incident. Witnesses were questioned by police at the time of the incident and interviewed by our research team four to five months later. Both statements were analyzed for the number and type of details reported and the accuracy of those details. Higher accuracy rates than those reported in the experimental literature were found in the witnesses' statements both at the time of the incident and several months later. Although the data base established in these studies is insufficient to judge the validity or invalidity of prior eyewitness research, it does appear that experimental research has not appropriately assessed eyewitnessing ability in regard to witnessing a striking, violent real-world event. The generalizability of experimental research to this type of event is therefore highly suspect. It is concluded that the combination of archival and field research will yield the data base needed for developing an understanding of the behaviour of actual eyewitnesses.
Second harmonic generation by strongly coupled exciton-plasmons: the role of polaritonic states in nonlinear dynamics
Creators: name: Sukharev, Maxim
name: Salomon, Adi
name: Zyss, Joseph
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate second harmonic generation (SHG) from hexagonal periodic arrays of triangular nano-holes of aluminum using a self-consistent methodology based on the hydrodynamics-Maxwell-Bloch approach. It is shown that angular polarization patterns of the far-field second harmonic response abide to three-fold symmetry constraints on tensors. When a molecular layer is added to the system and its parameters are adjusted to achieve the strong coupling regime between a localized plasmon mode and molecular excitons, Rabi splitting is observed from occurrence of both single- and two-photon transition peaks within the SHG power spectrum. It is argued that the splitting observed for both transitions results from direct transitions between lower and upper polaritonic states of the strongly coupled system. This interpretation can be accounted by a tailored three-level quantum model, with results in agreement with the unbiased numerical approach. Our results suggest the hybrid states formed in strongly coupled systems directly contribute to the nonlinear dynamics. This opens new directions in designing THz sources and nonlinear frequency converters.
description: submitted to JCP
Contagious: Why Things Catch On
Creators: name: นภดล ร่มโพธิ์
Publisher: name: คณะพาณิชยศาสตร์และการบัญชี มหาวิทยาลัยธรรมศาสตร์
Year: 2014

description: 144 (ต.ค.-ธ.ค. 57), 37, วารสารบริหารธุรกิจ JBA
Collective behavior in the North Rhine-Westphalia motorway network
Creators: name: Wang, Shanshan
name: Gartzke, Sebastian
name: Schreckenberg, Michael
name: Guhr, Thomas
Publisher: name: arXiv
Year: 2021
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: To understand the dynamics on complex networks, measurement of correlations is indispensable. In a motorway network, it is not sufficient to collect information on fluxes and velocities on all individual links, i.e. parts of the freeways between ramps and highway crosses. The interdependencies and mutual connections are also of considerable interest. We analyze correlations in the complete motorway network in North Rhine-Westphalia, the most populous state in Germany. We view the motorway network as a complex system consisting of road sections which interact via the motion of vehicles, implying structures in the corresponding correlation matrices. In particular, we focus on collective behavior, i.e. coherent motion in the whole network or in large parts of it. To this end, we study the eigenvalue and eigenvector statistics and identify significant sections in the motorway network. We find collective behavior in these significant sections and further explore its causes. We show that collectivity throughout the network cannot directly be related to the traffic states (free, synchronous and congested) in Kerner's three-phase theory. Hence, the degree of collectivity provides a new, complementary observable to characterize the motorway network.
พัฒนาการกฎหมายรัฐธรรมนูญของประเทศไทย
Creators: name: ทศพร มูลรัตน์
Publisher: name: มหาวิทยาลัยราชภัฏมหาสารคาม
Year: 2009
Subjects: กฎหมายรัฐธรรมนูญ, ประเทศไทย

description: 3, 3, วารสารมหาวิทยาลัยราชภัฏมหาสารคามมนุษยศาสตร์และสังคมศาสตร์
Additional file 10 of Relationships of gut microbiota, short-chain fatty acids, inflammation, and the gut barrier in Parkinson’s disease
Creators: name: Aho, Velma T. E.
name: Houser, Madelyn C.
name: Pereira, Pedro A. B.
name: Jianjun Chang
name: Rudi, Knut
name: Paulin, Lars
name: Hertzberg, Vicki
name: Auvinen, Petri
name: Tansey, Malú G.
name: Scheperjans, Filip
Publisher: name: figshare
Year: 2021
Subjects: subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: Cell Biology
subject: Genetics
subject: Physiology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: Immunology
subject: FOS: Clinical medicine
subject: 69999 Biological Sciences not elsewhere classified

description: Additional file 10: Scatterplots of genera relative abundances by SCFA levels. Scatterplots visualizing significant (p
Hypothesis Testing and Machine Learning: Interpreting Variable Effects in Deep Artificial Neural Networks using Cohen's f2
Creators: name: Messner, Wolfgang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Methodology (stat.ME)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Deep artificial neural networks show high predictive performance in many fields, but they do not afford statistical inferences and their black-box operations are too complicated for humans to comprehend. Because positing that a relationship exists is often more important than prediction in scientific experiments and research models, machine learning is far less frequently used than inferential statistics. Additionally, statistics calls for improving the test of theory by showing the magnitude of the phenomena being studied. This article extends current XAI methods and develops a model agnostic hypothesis testing framework for machine learning. First, Fisher's variable permutation algorithm is tweaked to compute an effect size measure equivalent to Cohen's f2 for OLS regression models. Second, the Mann-Kendall test of monotonicity and the Theil-Sen estimator is applied to Apley's accumulated local effect plots to specify a variable's direction of influence and statistical significance. The usefulness of this approach is demonstrated on an artificial data set and a social survey with a Python sandbox implementation.
description: 16 pages, 2 figures, 4 tables
Principle of learning sign rules by neural networks in qubit lattice models
Creators: name: Cao, Jin
name: Hu, Shijie
name: Yin, Zhiping
name: Xia, Ke
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A neural network is a powerful tool that can uncover hidden laws beyond human intuition. However, it often appears as a black box due to its complicated nonlinear structures. By drawing upon the Gutzwiller mean-field theory, we can showcase a principle of sign rules for ordered states in qubit lattice models. We introduce a shallow feed-forward neural network with a single hidden neuron to present these sign rules. We conduct systematical benchmarks in various models, including the generalized Ising, spin-$1/2$ XY, (frustrated) Heisenberg rings, triangular XY antiferromagnet on a torus, and the Fermi-Hubbard ring at an arbitrary filling. These benchmarks show that all the leading-order sign rule characteristics can be visualized in classical forms, such as pitch angles. Besides, quantum fluctuations can result in an imperfect accuracy rate quantitatively.
description: 12 pages, 11 figures
Tecnologías libres y abiertas para la investigación: Una mirada desde las humanidades
Creators: name: Arancio, Julieta
Publisher: name: Zenodo
Year: 2021
Subjects: hardware abierto
humanidades digitales
ciencia abierta

description: Presentación que fue parte de una charla organizada por la Asociación Argentina de Humanidades Digitales el día 19 de noviembre de 2021, en el marco de la Semana de la Ciencia y Tecnología.
New limits on the Lorentz/CPT symmetry through fifty gravitational-wave events
Creators: name: Wang, Ziming
name: Shao, Lijing
name: Liu, Chang
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Lorentz invariance plays a fundamental role in modern physics. However, tiny violations of the Lorentz invariance may arise in some candidate quantum gravity theories. Prominent signatures of the gravitational Lorentz invariance violation (gLIV) include anisotropy, dispersion, and birefringence in the dispersion relation of gravitational waves (GWs). Using a total of 50 GW events in the GW transient catalogs GWTC-1 and GWTC-2, we perform an analysis on the anisotropic birefringence phenomenon. The use of multiple events allows us to completely break the degeneracy among gLIV coefficients and globally constrain the coefficient space. Compared to previous results at mass dimensions 5 and 6 for the Lorentz-violating operators, we tighten the global limits of 34 coefficients by factors ranging from $2$ to $7$.
description: 7 pages, 2 figures, 2 tables; accepted by ApJ
On the Applicability of Language Models to Block-Based Programs
Creators: name: Griebl, Elisabeth
name: Fein, Benedikt
name: Obermüller, Florian
name: Fraser, Gordon
name: Just, René
Publisher: name: arXiv
Year: 2023
Subjects: subject: Programming Languages (cs.PL)
subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences
subject: D.2.5; D.2.3
subject: 68-04

description: Block-based programming languages like Scratch are increasingly popular for programming education and end-user programming. Recent program analyses build on the insight that source code can be modelled using techniques from natural language processing. Many of the regularities of source code that support this approach are due to the syntactic overhead imposed by textual programming languages. This syntactic overhead, however, is precisely what block-based languages remove in order to simplify programming. Consequently, it is unclear how well this modelling approach performs on block-based programming languages. In this paper, we investigate the applicability of language models for the popular block-based programming language Scratch. We model Scratch programs using n-gram models, the most essential type of language model, and transformers, a popular deep learning model. Evaluation on the example tasks of code completion and bug finding confirm that blocks inhibit predictability, but the use of language models is nevertheless feasible. Our findings serve as foundation for improving tooling and analyses for block-based languages.
description: To appear at the 45th IEEE/ACM International Conference on Software Engineering (ICSE'2023)
Predicting trajectory behaviour via machine-learned invariant manifolds
Creators: name: Krajňák, Vladimír
name: Naik, Shibabrat
name: Wiggins, Stephen
Publisher: name: arXiv
Year: 2021
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Machine Learning (cs.LG)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: In this paper, we use support vector machines (SVM) to develop a machine learning framework to discover phase space structures that distinguish between distinct reaction pathways. The SVM model is trained using data from trajectories of Hamilton's equations and works well even with relatively few trajectories. Moreover, this framework is specifically designed to require minimal a priori knowledge of the dynamics in a system. This makes our approach computationally better suited than existing methods for high-dimensional systems and systems where integrating trajectories is expensive. We benchmark our approach on Chesnavich's CH$_4^+$ Hamiltonian.
The Upper Bound on Antenna Gain and Its Feasibility as a Sum of Characteristic Gains
Creators: name: Capek, Miloslav
name: Jelinek, Lukas
Publisher: name: arXiv
Year: 2023
Subjects: subject: Applied Physics (physics.app-ph)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: The upper bound on antenna gain is expressed as a sum of lossy characteristic modes, specifically, as a sum of characteristic far fields squared. The procedure combines the favorable properties of Harrington's classical approach to maximum directivity and current-density-based approaches. The upper bound is valid for any antenna or array designed in a given design region for which optimal performance is determined. The decomposition into modes makes it possible to study the degrees of freedom of an obstacle, classify its radiation into normal or super-directive currents, and determine their compatibility with a given excitation. The bound considers an arbitrary shape of the design region and specific material distribution. The cost in Q-factor and radiation efficiency is studied. The extra constraint of a self-resonance current is imposed for an electrically small antenna. The examples verify the developed theory, demonstrate the procedure's utility, and provide helpful insight to antenna designers. The feasibility of the optimal gain is studied in detail on an example of end-fire arrays using the aforementioned decomposition of optimal current density into lossy characteristic modes.
description: 13 pages, 19 figures
Minimum-error discrimination of thermal states
Creators: name: Ghoreishi, Seyed Arash
name: Ziman, Mario
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study several variations of the question of minimum-error discrimination of thermal states. Besides of providing the optimal values for the probability of error, we also characterize the optimal measurements. For the case of a fixed Hamiltonian, we show that for a general discrimination problem the optimal measurement is the measurement in the energy basis of the Hamiltonian. We identify a critical temperature, determining whether the given temperature is best distinguishable from thermal state of very high or very low temperatures. Further, we investigate the decision problem of whether the thermal state is above or below some threshold value of the temperature. Also, in this case, the minimum-error measurement is the measurement in the energy basis. This is no longer the case once the thermal states to be discriminated have different Hamiltonians. We analyze a specific situation when the temperature is fixed but the Hamiltonians are different. For the considered case, we show the optimal measurement is independent of the fixed temperature and also of the strength of the interaction.
Signatures of many-body localization of quasiparticles in a flat band superconductor
Creators: name: Swaminathan, Koushik
name: Tadros, Poula
name: Peotta, Sebastiano
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We construct a class of exact eigenstates of the Hamiltonian obtained by projecting the Hubbard interaction term onto the flat band subspace of a generic lattice model. These exact eigenstates are many body states in which an arbitrary number of localized fermionic particles coexist with a sea of mobile Cooper pairs with zero momentum. By considering the dice lattice as an example, we provide evidence that these exact eigenstates are in fact manifestation of local integrals of motions of the projected Hamiltonian. In particular the spin and particle densities retain memory of the initial state for a very long time, if localized unpaired particles are present at the beginning of the time evolution. This shows that many-body localization of quasiparticles and superfluidity can coexist even in generic two-dimensional lattice models with flat bands, for which it is not known how to construct local conserved quantities. Our results open new perspectives on the old condensed matter problem of the interplay between superconductivity and localization.
The implementation of the unified transform to the nonlinear Schrödinger equation with periodic initial conditions
Creators: name: Deconinck, B.
name: Fokas, A. S.
name: Lenells, J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 35Q55, 37K15, 35G30

description: The unified transform method (UTM) provides a novel approach to the analysis of initial-boundary value problems for linear as well as for a particular class of nonlinear partial differential equations called integrable. If the latter equations are formulated in two dimensions (either one space and one time, or two space dimensions), the UTM expresses the solution in terms of a matrix Riemann-Hilbert (RH) problem with explicit dependence on the independent variables. For nonlinear integrable evolution equations, such as the celebrated nonlinear Schrödinger (NLS) equation, the associated jump matrices are computed in terms of the initial conditions and all boundary values. The unknown boundary values are characterized in terms of the initial datum and the given boundary conditions via the analysis of the so-called global relation. In general, this analysis involves the solution of certain nonlinear equations. In certain cases, called linearizable, it is possible to bypass this nonlinear step. In these cases, the UTM solves the given initial-boundary value problem with the same level of efficiency as the well-known inverse scattering transform solves the initial value problem on the infinite line. We show here that the initial-boundary value problem on a finite interval with $x$-periodic boundary conditions (which can alternatively be viewed as the initial value problem on a circle), belongs to the linearizable class. Indeed, by employing certain transformations of the associated RH problem and by using the global relation, the relevant jump matrices can be expressed explicitly in terms of the so-called scattering data, which are computed in terms of the initial datum. Details are given for NLS, but similar considerations are valid for other well-known integrable evolution equations, including the Korteweg-de Vries (KdV) and modified KdV equations.
description: 14 pages, includes announcements of results in arXiv:2103.04728
Continuous phase transitions between fractional quantum Hall states and symmetry-protected topological states
Creators: name: Wu, Ying-Hai
name: Tu, Hong-Hao
name: Cheng, Meng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We study quantum phase transitions in Bose-Fermi mixtures driven by interspecies interaction in the quantum Hall regime. In the absence of such an interaction, the bosons and fermions form their respective fractional quantum Hall (FQH) states at certain filling factors. A symmetry-protected topological (SPT) state is identified as the ground state for strong interspecies interaction. The phase transitions between them are proposed to be described by Chern-Simons-Higgs field theories. For a simple microscopic Hamiltonian, we present numerical evidence for the existence of the SPT state and a continuous transition to the FQH state. It is also found that the entanglement entropy between the bosons and fermions exhibits scaling behavior in the vicinity of this transition.
description: 9 pages, 6 figures
Toroidal versus poloidal magnetic fields in Sun-like stars: a rotation threshold
Creators: name: Petit, P.
name: Dintrans, B.
name: Solanki, S. K.
name: Donati, J. -F.
name: Auriere, M.
name: Lignieres, F.
name: Morin, J.
name: Paletou, F.
name: Ramirez, J.
name: Catala, C.
name: Fares, R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: From a set of stellar spectropolarimetric observations, we report the detection of surface magnetic fields in a sample of four solar-type stars, namely HD 73350, HD 76151, HD 146233 (18 Sco) and HD 190771. Assuming that the observed variability of polarimetric signal is controlled by stellar rotation, we establish the rotation periods of our targets, with values ranging from 8.8 d (for HD 190771) to 22.7 d (for HD 146233). Apart from rotation, fundamental parameters of the selected objects are very close to the Sun's, making this sample a practical basis to investigate the specific impact of rotation on magnetic properties of Sun-like stars. We reconstruct the large-scale magnetic geometry of the targets as a low-order (l<10) spherical harmonics expansion of the surface magnetic field. From the set of magnetic maps, we draw two main conclusions. (a) The magnetic energy of the large-scale field increases with rotation rate. The increase of chromospheric emission with the mean magnetic field is flatter than observed in the Sun. Since the chromospheric flux is also sensitive to magnetic elements smaller than those contributing to the polarimetric signal, this observation suggests that a larger fraction of the surface magnetic energy is stored in large scales as rotation increases. (b) Whereas the magnetic field is mostly poloidal for low rotation rates, more rapid rotators host a large-scale toroidal component in their surface field. From our observations, we infer that a rotation period lower than ~12 days is necessary for the toroidal magnetic energy to dominate over the poloidal component.
description: MNRAS (in press)
Leveraging Multiple Relations for Fashion Trend Forecasting Based on Social Media
Creators: name: Ding, Yujuan
name: Ma, Yunshan
name: Liao, Lizi
name: Wong, Wai Keung
name: Chua, Tat-Seng
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Information Retrieval (cs.IR)
subject: Multimedia (cs.MM)
subject: FOS: Computer and information sciences

description: Fashion trend forecasting is of great research significance in providing useful suggestions for both fashion companies and fashion lovers. Although various studies have been devoted to tackling this challenging task, they only studied limited fashion elements with highly seasonal or simple patterns, which could hardly reveal the real complex fashion trends. Moreover, the mainstream solutions for this task are still statistical-based and solely focus on time-series data modeling, which limit the forecast accuracy. Towards insightful fashion trend forecasting, previous work [1] proposed to analyze more fine-grained fashion elements which can informatively reveal fashion trends. Specifically, it focused on detailed fashion element trend forecasting for specific user groups based on social media data. In addition, it proposed a neural network-based method, namely KERN, to address the problem of fashion trend modeling and forecasting. In this work, to extend the previous work, we propose an improved model named Relation Enhanced Attention Recurrent (REAR) network. Compared to KERN, the REAR model leverages not only the relations among fashion elements but also those among user groups, thus capturing more types of correlations among various fashion trends. To further improve the performance of long-range trend forecasting, the REAR method devises a sliding temporal attention mechanism, which is able to capture temporal patterns on future horizons better. Extensive experiments and more analysis have been conducted on the FIT and GeoStyle datasets to evaluate the performance of REAR. Experimental and analytical results demonstrate the effectiveness of the proposed REAR model in fashion trend forecasting, which also show the improvement of REAR compared to the KERN.
description: 12 pages, 8 figures
Entangling dynamics from effective rotor/spin-wave separation in U(1)-symmetric quantum spin models
Creators: name: Roscilde, Tommaso
name: Comparin, Tommaso
name: Mezzacapo, Fabio
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The non-equilibrium dynamics of quantum spin models is a most challenging topic, due to the exponentiality of Hilbert space; and it is central to the understanding of the many-body entangled states that can be generated by state-of-the-art quantum simulators. A particularly important class of evolutions is the one governed by U(1) symmetric Hamiltonians, initialized in a state which breaks the U(1) symmetry -- the paradigmatic example being the evolution of the so-called one-axis-twisting (OAT) model, featuring infinite-range interactions between spins. In this work we show that the dynamics of the OAT model can be closely reproduced by systems with power-law-decaying interactions, thanks to an effective separation between the zero-momentum degrees of freedom, associated with the so-called Anderson tower of states, and reconstructing a OAT model; and finite-momentum ones, associated with spin-wave excitations. This mechanism explains quantitatively the recent numerical observation of spin squeezing and Schrödinger-cat generation in the dynamics of dipolar Hamiltonians; and it paves the way for the extension of this observation to a much larger class of models of immediate relevance for quantum simulations.
description: 5+3 pages, 3+2 figures
Quasi-Homogeneous Backward-Wave Plasmonic Structures: Theory and Accurate Simulation
Creators: name: Tsukerman, Igor
Publisher: name: arXiv
Year: 2008
Subjects: subject: Optics (physics.optics)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Backward waves and negative refraction are shown to exist in plasmonic crystals whose lattice cell size is a very small fraction of the vacuum wavelength (less than 1/40th in an illustrative example). Such ``quasi-homogeneity'' is important, in particular, for high-resolution imaging. Real and complex Bloch bands are computed using the recently developed finite-difference calculus of ``Flexible Local Approximation MEthods'' (FLAME) that produces linear eigenproblems, as opposed to quadratic or nonlinear ones typical for other techniques. FLAME dramatically improves the accuracy by incorporating local analytical approximations of the solution into the numerical scheme.
description: 4 pages, 3 figures
A non-singular, field-only surface integral method for interactions between electric and magnetic dipoles and nano-structures
Creators: name: Sun, Qiang
name: Klaseboer, Evert
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Classical Physics (physics.class-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: With the development of condensed-matter physics and nanotechnology, attention has turned to the fields near and on surfaces that result from interactions between electric dipole radiation and mesoscale structures. It is hoped that studying these fields will further our understanding of optical phenomena in nano-optics, quantum mechanics, electromagnetics and sensing using solid-state photon emitters. Here, we describe a method for implementing dynamic electric and magnetic dipoles in the frequency domain into a non-singular field-only surface integral method. We show that the effect of dipoles can conveniently be described as a relatively simple term in the integral equations, which fully represents how they drive the fields and interactions. Also, due to the non-singularity, our method can calculate the electric and magnetic fields on the surfaces of objects in both near and far fields with the same accuracy, which makes it an ideal tool to investigate nano-optical phenomena. The derivation of the framework is given and tested against a Mie theory alike formula. Some interesting examples are shown involving the interaction of dipoles with different types of mesoscale structures including parabolic nano-antennas and gold probes.
Lower Bounds for the Advection-Hyperdiffusion Equation
Creators: name: Bleitner, Fabian
name: Nobili, Camilla
Publisher: name: arXiv
Year: 2023
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Motivated by [7], we study the advection-hyperdiffusion equation in the whole space in two and three dimensions with the goal of understanding the decay in time of the $H^{-1}$- and $L^2$-norm of the solutions. We view the advection term as a perturbation of the hyperdiffusion equation and employ the Fourier-splitting method first introduced by Schonbek in [8] for scalar parabolic equations and later generalized to a broader class of equations including Navier-Stokes equations and magneto-hydrodynamic systems. This approach consists of decomposing the Fourier space along a sphere with radius decreasing in time. Combining the Fourier-splitting method with classical PDE techniques applied to the hyperdiffusion equation we find a lower bound for the $H^{-1}$-norm by interpolation.
description: 16 pages
User-Centric Perspective in Random Access Cell-Free Aided by Spatial Separability
Creators: name: Croisfelt, Victor
name: Abrão, Taufik
name: Marinello, José Carlos
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Theory (cs.IT)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: In a cell-free massive multiple-input multiple-output (CF-mMIMO) network, multiple access points (APs) actively cooperate to serve users' equipment (UEs). We consider how the random access (RA) problem can be addressed by such a network under the occurrence of pilot collisions. To find a solution, we embrace the user-centric perspective, which basically dictates that only a preferred set of APs needs to serve a UE. Due to the success of the strongest-user collision resolution (SUCRe) protocol for cellular (Ce) mMIMO, we extend it by considering the new setting. Besides, we establish that the user-centric perspective naturally equips a CF network with robust fundamentals for resolving collisions. We refer to this foundation as spatial separability, which enables multiple colliding UEs to access the network simultaneously. We then propose two novel RA protocols for CF-mMIMO: i) the baseline cell-free (BCF) that resolves collisions with the concept of spatial separability alone, and ii) the cell-free SUCRe (CF-SUCRe) that combines SUCRe and spatial separability principle to resolve collisions. We evaluate our proposed RA protocols against the Ce-SUCRe. Respectively, the BCF and CF-SUCRe can support 7x and 4x more UEs' access on average compared to the Ce-SUCRe with an average energy efficiency gain based on total power consumed (TPC) by the network per access attempt of 52x and 340x. Among our procedures, even with a higher overhead, the CF-SUCRe is superior to BCF regarding TPC per access attempt. This is because the combination of methods for collision resolution allows many APs to be disconnected from the RA process without sacrificing much the performance. Finally, our numerical results presented in this work can be reproduced using the code package available on: github.com/victorcroisfelt/cf-ra-spatial-separability.
description: 14 pages, 8 figures
Student Barriers to Active Learning in Synchronous Online Classes: Characterization, Reflections, and Suggestions
Creators: name: Mogavi, Reza Hadi
name: Zhao, Yankun
name: Haq, Ehsan Ul
name: Hui, Pan
name: Ma, Xiaojuan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: As more and more face-to-face classes move to online environments, it becomes increasingly important to explore any emerging barriers to students' learning. This work focuses on characterizing student barriers to active learning in synchronous online environments. The aim is to help novice educators develop a better understanding of those barriers and prepare more student-centered course plans for their active online classes. Towards this end, we adopt a qualitative research approach and study information from different sources: social media content, interviews, and surveys from students and expert educators. Through a thematic analysis, we craft a nuanced list of students' online active learning barriers within the themes of human-side, technological, and environmental barriers. Each barrier is explored from the three aspects of frequency, importance, and exclusiveness to active online classes. Finally, we conduct a summative study with 12 novice educators and explain the benefits of using our barrier list for course planning in active online classes.
description: Accepted in the Proceedings of the Eighth ACM Conference on Learning @ Scale (L@S '21)
Rotor/spin-wave theory for quantum spin models with U(1) symmetry
Creators: name: Roscilde, Tommaso
name: Comparin, Tommaso
name: Mezzacapo, Fabio
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The static and dynamics properties of finite-size lattice quantum spin models which spontaneously break a continuous $U(1)$ symmetry in the thermodynamic limit are of central importance for a wide variety of physical systems, from condensed matter to quantum simulation. Such systems are characterized by a Goldstone excitation branch, terminating in a zero mode whose theoretical treatment within a linearized approach leads to divergencies on finite-size systems, revealing that the assumption of symmetry breaking is ill-defined away from the thermodynamic limit. In this work we show that, once all its non-linearities are taken into account, the zero mode corresponds exactly to a U(1) quantum rotor, related to the Anderson tower of states expected in systems showing symmetry breaking in the thermodynamic limit. The finite-momentum modes, when weakly populated, can be instead safely linearized (namely treated within spin-wave theory) and effectively decoupled from the zero mode. This picture leads to an approximate separation of variables between rotor and spin-wave ones, which allows for a correct description of the ground-state and low-energy physics. Most importantly, it offers a quantitative treatment of the finite-size non-equilibrium dynamics -- following a quantum quench -- dominated by the zero mode, for which a linearized approach fails. Focusing on the 2$d$ XX model with power-law decaying interactions, we compare our equilibrium predictions with unbiased quantum Monte Carlo results and exact diagonalization; and our non-equilibrium results with time-dependent variational Monte Carlo. The agreement is remarkable for all interaction ranges, and it improves the longer the range. Our rotor/spin-wave theory defines a successful strategy for the application of spin-wave theory and its extensions to finite-size systems at equilibrium or away from it.
description: 18 pages, 5 figures; v2: a few mistakes fixed in Sec. VI and App. B
Utility indifference Option Pricing Model with a Non-Constant Risk-Aversion under Transaction Costs and Its Numerical Approximation
Creators: name: Polvora, Pedro
name: Sevcovic, Daniel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: Pricing of Securities (q-fin.PR)
subject: FOS: Mathematics
subject: FOS: Economics and business
subject: 45K05, 35K58, 34G20, 91G20

description: Our goal is to analyze the system of Hamilton-Jacobi-Bellman equations arising in derivative securities pricing models. The European style of an option price is constructed as a difference of the certainty equivalents to the value functions solving the system of HJB equations. We introduce the transformation method for solving the penalized nonlinear partial differential equation. The transformed equation involves possibly non-constant the risk aversion function containing the negative ratio between the second and first derivatives of the utility function. Using comparison principles we derive useful bounds on the option price. We also propose a finite difference numerical discretization scheme with some computational examples.
Formation of regular structures in the process of phase separation
Creators: name: Krekhov, Alexei
Publisher: name: arXiv
Year: 2008
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: Phase separation under directional quenching has been studied in a Cahn-Hilliard model. In distinct contrast to the disordered patterns which develop under a homogeneous quench periodic stripe patterns are generated behind the quench front. Their wavelength is uniquely defined by the velocity of the quench interface in a wide range. Numerical simulations match perfectly analytical results obtained in the limit of small and large velocities of the quench interface. Additional periodic modulation of the quench interface may lead to cellular patterns. The quenching protocols analyzed in this paper are expected to be an effective tool in technological applications to design nanostructured materials.