cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Gamma-ray bursts and collisionless shocks
Creators: name: Waxman, E.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Particle acceleration in collisionless shocks is believed to be responsible for the production of cosmic-rays over a wide range of energies, from few GeV to >10^{20}eV, as well as for the non-thermal emission of radiation from a wide variety of high energy astrophysical sources. A theory of collisionless shocks based on first principles does not, however, exist. Observations of gamma-ray burst (GRB) "afterglows" provide a unique opportunity for diagnosing the physics of relativistic collisionless shocks. Most GRBs are believed to be associated with explosions of massive stars. Their "afterglows," delayed low energy emission following the prompt burst of gamma-rays, are well accounted for by a model in which afterglow radiation is due to synchrotron emission of electrons accelerated in relativistic collisionless shock waves driven by the explosion into the surrounding plasma. Within the framework of this model, some striking characteristics of collisionless relativistic shocks are implied. These include the generation of downstream magnetic fields with energy density exceeding that of the upstream field by ~8 orders of magnitude, the survival of this strong field at distances ~10^{10} skin-depths downstream of the shock, and the acceleration of particles to a power-law energy spectrum, d\log n/d\log E ~ -2, possibly extending to 10^{20}eV. I review in this talk the phenomenological considerations, based on which these characteristics are inferred, and the challenges posed to our current models of particle acceleration and magnetic field generation in collisionless shocks. Some recent theoretical results derived based on the assumption of a self-similar shock structure are briefly discussed.
description: Expanded discussion of the derivation of collisionless shock characteristics from afterglow observations. Accepted to Plasma Phys. and Controlled Fusion (Invited review, 33rd annual European Physical Society Conference on Plasma Physics, Rome 2006)
Learning Processes and Knowledge Transfer in a Native Bush-Oriented Society: Implications For Schooling
Creators: name: Larose, Francois
Publisher: name: Canadian Journal of Native Education
Year: 2021

description: Based on field research among Northwestern Quebec Algonquin bands since 1983, some general elements of bush-oriented Algonquin technology and ideology are summarized in a discussion of relationships between material culture and learning. Play and locus of control are central considerations. A general description of "traditional" educational methods is followed by an attempt to describe systematically the inferences on Native informal learning stmctures, using elements of Bandura’s (1986) social cognitive theory.
description: Canadian Journal of Native Education, Vol. 18 No. 1 (1991)
Atomic-scale investigation of the irradiation-resistant effect of symmetric tilt grain boundaries of Fe-Ni-Cr alloy
Creators: name: Liu, Zhijia
name: Feng, Zehua
name: Wang, Heran
name: Zhang, Yunpeng
name: Chen, Zheng
name: Meng, Fanchao
name: Zhang, Jing
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In this paper, the Fe-20Ni-25Cr alloy that is used for fuel cladding or pressure vessels with various grain boundaries (GBs) was investigated by employing molecular dynamics simulations. The bi-crystals comprised of Σ3(111), Σ3(112), Σ9(114), Σ11(113), Σ19(116), and Σ17(223) types GBs were considered to systematically examine the interplay between irradiation defects, irradiation microstructure evolution under stress, and irradiation mechanical properties with irradiation intensity, coincidence site lattice parameter, tilt angle, and GB thickness. It is found that irradiated vacancies and interstitials are annihilated by competitive GB absorption and recombination. Bias absorption of interstitials is observed for most bi-crystals except Σ3(111) and Σ11(113) at 15 keV incident energy, and results in abundant residual vacancies clusters in grain interior. In addition, different GBs exhibit quite diverse irradiation defect sink ability, and the number of residual vacancies is inversely related to the GB thickness, where Σ3(111) and Σ11(113) GBs with narrow GB thickness are weak in defect absorption and the others are strong. Furthermore, uniaxial tensile simulations perpendicular to the GB reveal that all of the mechanical performance of bi-crystals deteriorates after irradiation, which originates from dislocation propagation facilitated by irradiation defect clusters. In particular, regardless of whether the irradiation is applied, the maximum tensile strain, toughness, and Youngs modulus are monotonically correlated with GB tilt angle, while the ultimate tensile strength is stable for larger GB CSL parameter. Finally, on the basis of the evolution of the irradiation defects, microstructures, and mechanical performances, we proposed guidelines of rational design of irradiation-resistant Fe-Ni-Cr alloy.
A Study of 13 Powerful Classical Double Radio Galaxies
Creators: name: Kharb, P.
name: O'Dea, C.
name: Baum, S.
name: Daly, R.
name: Mory, M.
name: Donahue, M.
name: Guerra, E.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have carried out an extensive study of a sample of 13 large, powerful Fanaroff-Riley type II radio galaxies with the Very Large Array in multiple configurations at 330 MHz, 1.4, 5 and 8 GHz. We present the total intensity, polarization, spectral index, and rotation measure maps of the sources. On the whole the 13 FRII sources have symmetric structures with arm-length ratios close to unity, small misalignment angles and low values of radio core prominence, suggesting that these radio galaxies lie close to the plane of the sky. We have revisited some well known radio galaxy correlations using a large combined dataset comprising our radio galaxies and others from the literature. We confirm that the hotspot size correlates with the core-hotspot distance. The hotspot spectral index is correlated with, and flatter than the lobe spectral index, consistent with the assumptions of spectral aging models. Both the hotspot and lobe spectral index are correlated with redshift. The depolarization asymmetry in the lobes is not correlated with the radio core prominence or misalignment angle, which are statistical indicators of orientation. The `Liu-Pooley' correlation of lobe depolarization with the lobe spectral index is significant in our radio galaxy sample. Further, the lobe with the steeper spectral index and greater depolarization is shorter and fatter. The arm-length ratio seems to be correlated with the misalignment angle between the two sides of the radio source and strongly anti-correlated with the axial ratio, consistent with environmental effects and/or a change in the outflow direction. In this sample, asymmetries in the local environments and/or motion of the outflow axis are likely to be more important than relativistic beaming effects.
description: 91 pages, 69 figures, Accepted for publication in the ApJ Supp. Ser., Paper substantially revised after additional referee-reports, Conclusions remain largely unchanged
Hebbian Semi-Supervised Learning in a Sample Efficiency Setting
Creators: name: Lagani, Gabriele
name: Falchi, Fabrizio
name: Gennaro, Claudio
name: Amato, Giuseppe
Publisher: name: arXiv
Year: 2021
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: We propose to address the issue of sample efficiency, in Deep Convolutional Neural Networks (DCNN), with a semi-supervised training strategy that combines Hebbian learning with gradient descent: all internal layers (both convolutional and fully connected) are pre-trained using an unsupervised approach based on Hebbian learning, and the last fully connected layer (the classification layer) is trained using Stochastic Gradient Descent (SGD). In fact, as Hebbian learning is an unsupervised learning method, its potential lies in the possibility of training the internal layers of a DCNN without labels. Only the final fully connected layer has to be trained with labeled examples. We performed experiments on various object recognition datasets, in different regimes of sample efficiency, comparing our semi-supervised (Hebbian for internal layers + SGD for the final fully connected layer) approach with end-to-end supervised backprop training, and with semi-supervised learning based on Variational Auto-Encoder (VAE). The results show that, in regimes where the number of available labeled samples is low, our semi-supervised approach outperforms the other approaches in almost all the cases.
description: 18 pages, 9 figures, 3 tables, accepted by Elsevier Neural Networks
Locally D-optimal designs based on a class of composed models resulted from blending Emax and one-compartment models
Creators: name: Fang, X.
name: Hedayat, A. S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Methodology (stat.ME)
subject: Statistics Theory (math.ST)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: 62K05 (Primary)

description: A class of nonlinear models combining a pharmacokinetic compartmental model and a pharmacodynamic Emax model is introduced. The locally D-optimal (LD) design for a four-parameter composed model is found to be a saturated four-point uniform LD design with the two boundary points of the design space in the LD design support. For a five-parameter composed model, a sufficient condition for the LD design to require the minimum number of sampling time points is derived. Robust LD designs are also investigated for both models. It is found that an LD design with $k$ parameters is equivalent to an LD design with $k-1$ parameters if the linear parameter in the two composed models is a nuisance parameter. Assorted examples of LD designs are presented.
description: Published in at http://dx.doi.org/10.1214/009053607000000776 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Baryonic Collapse within Dark Matter Halos and the Formation of Gaseous Galactic Disks
Creators: name: Adams, Fred C.
name: Bloch, Anthony M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: This paper constructs an analytic framework for calculating the assembly of galactic disks from the collapse of gas within dark matter halos, with the goal of determining the surface density profiles. Gas parcels (baryons) fall through the potentials of dark matter halos on nearly ballistic, zero energy orbits and collect in a rotating disk. The dark matter halos have a nearly universal form, as determined previously through numerical simulations. The calculation is first carried out for a variety of pre-collapse mass distributions and rotation profiles, including polytropic spheres in hydrostatic equilibrium with the halo potential. The resulting disk surface density profiles have nearly power-law forms, with well-defined edges. This idealized scenario is generalized to include non-spherical starting states and multiple accretion events (due to gas being added to the halo via merger events). This latter complication is explored in detail and considers a log-normal distribution for the angular momenta of the pre-collapse states. If this distribution is wide, then the composite surface density approaches a universal power-law form, independent of the shape of the constituent profiles. When the angular momentum distribution has an intermediate width, the composite surface density attains a nearly exponential form, roughly consistent with profiles of observed galaxies.
description: 47 pages including 12 figures, accepted to ApJ
Adsorption from Binary Liquid Solutions into Mesoporous Silica: A Capacitance Isotherm on 5CB Nematogen/Methanol Mixtures
Creators: name: Kityk, Andriy V.
name: Gor, Gennady Y.
name: Huber, Patrick
Publisher: name: arXiv
Year: 2021
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Applied Physics (physics.app-ph)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: We present a capacitance method to measure the adsorption of rod-like nematogens (4-cyano-4'-pentylbiphenyl, 5CB) from a binary liquid 5CB/methanol solution into a monolithic mesoporous silica membrane traversed by tubular pores with radii of 5.4 nm at room temperature. The resulting adsorption isotherm is reminiscent of classical type II isotherms of gas adsorption in mesoporous media. Its analysis by a model for adsorption from binary solutions, as inspired by the Brunauer-Emmett-Teller (BET) approach for gas adsorption on solid surfaces, indicates that the first adsorbed monolayer consists of flat-lying (homogeneously anchored) 5CB molecules at the pore walls. An underestimation of the adsorbed 5CB amount by the adsorption model compared to the measured isotherm for high 5CB concentrations hints towards a capillary filling transition in the mesopores similar to capillary condensation, i.e. film-growth at the pore walls is replaced by filling of the pore centers by the liquid crystal. The experimental method and thermodynamic analysis presented here can easily be adapted to other binary liquid solutions and thus allows a controlled filling of mesoporous materials with non-volatile molecular systems.
description: 10 pages, 4 figures, submitted to the journal "Molecular Physics" as a contribution to the special issue in honour of Professor Gerhard Findenegg (Technical University Berlin)
Οι Ναοί της Βόρειας Χαλκιδικής. Κειμήλια, Παλαίτυπα και η Ιστορία τους (παλαίτυπα, εικόνες, εκκλησιαστικά σκεύη, έγγραφα)
Creators: name: Σαμολαδάς, Γεώργιος Κωνσταντίνου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Χαλκιδική
Εκκλησία
Παράδοση
Chalkidiki
Church
Tradition

description: Σκοπός της παρούσας έρευνας υπήρξε η ανάδειξη της πλούσιας εκκλησιαστικής και πολιτιστικής παράδοσης της Βόρειας Χαλκιδικής. Με την έρευνα αυτή διαπιστώθηκε πως η περιοχή αυτή αποτέλεσε σημείο αναφοράς ανά τους αιώνες και σημαντικό τμήμα της Μακεδονικής εκκλησιαστικής παράδοσης. Τα στοιχεία που συλλέξαμε για την παρούσα εργασία υπήρξαν πρωτότυπα και αυτό διότι για άλλη μια φορά φάνηκε η έλλειψη μιας επιστημονικά τεκμηριωμένης αρχειοθέτησης, με αποτέλεσμα να δυσκολευτούμε στη συλλογή αυτών των στοιχείων
description: The purpose of this research was to right light the rich ecclesiastical and cultural tradition of northern Halkidiki. This research has found that this area has been a reference point for centuries and an important part of Macedonian church tradition. The data we collected from this research were original and because there was no scientifically documented archive to make it difficult to collect these data
Betweenness Centrality of Fractal and Non-Fractal Scale-Free Model Networks and Tests on Real Networks
Creators: name: Kitsak, Maksim
name: Havlin, Shlomo
name: Paul, Gerald
name: Riccaboni, Massimo
name: Pammolli, Fabio
name: Stanley, H. Eugene
Publisher: name: arXiv
Year: 2007
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: We study the betweenness centrality of fractal and non-fractal scale-free network models as well as real networks. We show that the correlation between degree and betweenness centrality $C$ of nodes is much weaker in fractal network models compared to non-fractal models. We also show that nodes of both fractal and non-fractal scale-free networks have power law betweenness centrality distribution $P(C)\sim C^{-δ}$. We find that for non-fractal scale-free networks $δ= 2$, and for fractal scale-free networks $δ= 2-1/d_{B}$, where $d_{B}$ is the dimension of the fractal network. We support these results by explicit calculations on four real networks: pharmaceutical firms (N=6776), yeast (N=1458), WWW (N=2526), and a sample of Internet network at AS level (N=20566), where $N$ is the number of nodes in the largest connected component of a network. We also study the crossover phenomenon from fractal to non-fractal networks upon adding random edges to a fractal network. We show that the crossover length $\ell^{*}$, separating fractal and non-fractal regimes, scales with dimension $d_{B}$ of the network as $p^{-1/d_{B}}$, where $p$ is the density of random edges added to the network. We find that the correlation between degree and betweenness centrality increases with $p$.
description: 19 pages, 6 figures. Submitted to PRE
First principles vs second principles: Role of charge self-consistency in strongly correlated systems
Creators: name: Acharya, Swagata
name: Pashov, Dimitar
name: Rudenko, Alexander N.
name: Rösner, Malte
name: van Schilfgaarde, Mark
name: Katsnelson, Mikhail I.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: First principles approaches have been successful in solving many-body Hamiltonians for real materials to an extent when correlations are weak or moderate. As the electronic correlations become stronger often embedding methods based on first principles approaches are used to better treat the correlations by solving a suitably chosen many-body Hamiltonian with a higher level theory. Such combined methods are often referred to as second principles approaches. At such level of the theory the self energy, i.e. the functional that embodies the stronger electronic correlations, is either a function of energy or momentum or both. The success of such theories is commonly measured by the quality of the self energy functional. However, self-consistency in the self-energy should, in principle, also change the real space charge distribution in a correlated material and be able to modify the electronic eigenfunctions, which is often undermined in second principles approaches. Here we study the impact of charge self-consistency within two example cases: TiSe$_{2}$, a three-dimensional charge-density-wave candidate material, and CrBr$_{3}$, a two-dimensional ferromagnet, and show how real space charge re-distribution due to correlation effects taken into account within a first principles Green's function based many-body perturbative approach is key in driving qualitative changes to the final electronic structure of these materials.
description: 10 pages, 4 figures
Uniqueness for linear integro-differential equations in the real line and applications
Creators: name: Felipe-Navarro, Juan-Carlos
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: In this work we prove the uniqueness of solutions to the nonlocal linear equation $L φ- c(x)φ= 0$ in $\mathbb{R}$, where $L$ is an elliptic integro-differential operator, in the presence of a positive solution or of an odd solution vanishing only at zero. As an application, we deduce the nondegeneracy of layer solutions (bounded and monotone solutions) to the semilinear problem $L u = f(u)$ in $\mathbb{R}$ when the nonlinearity is of Allen-Cahn type. To our knowledge, this is the first work where such uniqueness and nondegeneracy results are proven in the nonlocal framework when the Caffarelli-Silvestre extension technique is not available. Our proofs are based on a nonlocal Liouville-type method developed by Hamel, Ros-Oton, Sire, and Valdinoci for nonlinear problems in dimension two.
description: Final version to appear in Calculus of Variations and Partial Differential Equations
A Dramatic Approach to Native Teacher Education
Creators: name: Foreman, Kathleen
Publisher: name: Canadian Journal of Native Education
Year: 2021

description: The basic precepts and methods of educational drama are reviewed and compared to some of the distinctive Native learning patterns discussed in the literature, with specific reference to the patterns of Native learning discussed by More (1987). Based on the author’s experience, on systematic observation, and with reference to participant evaluation, it appears that the inclusion of educational drama as an approach to Native teacher education is recommended.
description: Canadian Journal of Native Education, Vol. 18 No. 1 (1991)
Why Security Defects Go Unnoticed during Code Reviews? A Case-Control Study of the Chromium OS Project
Creators: name: Paul, Rajshakhar
name: Turzo, Asif Kamal
name: Bosu, Amiangshu
Publisher: name: arXiv
Year: 2021
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Peer code review has been found to be effective in identifying security vulnerabilities. However, despite practicing mandatory code reviews, many Open Source Software (OSS) projects still encounter a large number of post-release security vulnerabilities, as some security defects escape those. Therefore, a project manager may wonder if there was any weakness or inconsistency during a code review that missed a security vulnerability. Answers to this question may help a manager pinpointing areas of concern and taking measures to improve the effectiveness of his/her project's code reviews in identifying security defects. Therefore, this study aims to identify the factors that differentiate code reviews that successfully identified security defects from those that missed such defects. With this goal, we conduct a case-control study of Chromium OS project. Using multi-stage semi-automated approaches, we build a dataset of 516 code reviews that successfully identified security defects and 374 code reviews where security defects escaped. The results of our empirical study suggest that the are significant differences between the categories of security defects that are identified and that are missed during code reviews. A logistic regression model fitted on our dataset achieved an AUC score of 0.91 and has identified nine code review attributes that influence identifications of security defects. While time to complete a review, the number of mutual reviews between two developers, and if the review is for a bug fix have positive impacts on vulnerability identification, opposite effects are observed from the number of directories under review, the number of total reviews by a developer, and the total number of prior commits for the file under review.
Gravitational waves from axion-like particle cosmic string-wall networks
Creators: name: Gelmini, Graciela B.
name: Simpson, Anna
name: Vitagliano, Edoardo
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Axion-like particles (ALPs) are a compelling candidate for dark matter (DM), whose production is associated with the formation of a string-wall network. If walls bounded by strings persist, which requires the potential to have multiple local minima ($N>1$), they must annihilate before they become dominant. They annihilate mostly into gravitational waves and non-relativistic ALPs. We show that for ALPs other than the QCD axion these gravitational waves, if produced at temperatures below 100 eV, could be detected by future cosmological probes for ALPs with mass from $10^{-16}$ to $10^{6}$ eV that could constitute the entirety of the DM.
description: 7 pages, 3 figures. Matches published version
Universe's Skeleton Sketched
Creators: name: Linder, Eric V.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The deepest and clearest maps yet of the Universe's skeleton of dark matter structure present a picture broadly in concord with favoured models - although puzzling discrepancies remain.
description: News & Views, Nature 445, 273 (2007)
Μελέτη καταλυτικής αναγωγής α,β-ακόρεστων καρβονυλικών ενώσεων στις αλλυλικές αλκοόλες με τη χρήση νανοσωματιδίων χρυσού και υδροσιλανίων
Creators: name: Λωτίδου, Κυριακή Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Αναγωγή
Αλλυλικές Αλκοόλες
Υδροσιλάνια
Reduction
Allylic Alcohols
Hydrosilanes

description: Στα πλαίσια της παρούσας μεταπτυχιακής εργασίας μελετήθηκε η σύνθεση και η εκλεκτική αναγωγή α,β-ακόρεστων καρβονυλικών ενώσεων (αλδεϋδών, κετονών) προς τις αντίστοιχες α,β-ακόρεστες αλκοόλες με χρήση του ετερογενούς καταλυτικού συστήματος Au/Al2O3/ΤΜDS σε ήπιες συνθήκες αντίδρασης Για το σκοπό αυτό, συντέθηκαν διάφορες αλλυλικές αλδεύδες και μια σειρά αλλυλικών κετονών. Στην παρούσα μελέτη, επιτεύχθηκε η εκλεκτική αναγωγή των αλλυλικών αλδευδών προς τις αντίστοιχες αλλυλικές αλκοόλες κάτω από ήπιες συνθήκες αντίδρασης, χρησιμοποιώντας 20 mg Au/Al2O3, 2-4eq TMDS, σε διαλύτη μεθανόλη σε θερμοκρασία δωματίου εντός 4 ωρών. Η καταλυτική αυτή μεθοδολογία βρέθηκε να υπερτερεί σε σχέση με τα συνήθη αναγωγικά NaBH4, LiAlH4, ως προς τις μη αδρανείς συνθήκες χρήσης των αντιδραστηρίων και την ευκολία απομόνωσης των αντίστοιχων αλλυλικών αλκοολών
description: In this MSc thesis, synthesis and chemoselective reduction of a,b conjugated carbonyl compounds (aldehydes, ketones) to the corresponding a,b unsaturated alcohols using the Au/ Al2O3/TMDS heterogeneous catalytic system under mild conditions were studied. To this end, various allylic aldehydes and a series of a allyllic ketones were synthesized. In the present study, selective reduction of a allylic aldehydes to the corresponding allylic alcohols under mild conditions, was achieved using 20 mg Au/Al2O3, 2-4eq of TMDS in methanol at room temperature within 4h. This catalytic methodology was found to be superior to the usual NaBH4 and LiAlH4 reductants, in the reduced amount of catalyst, the inert reagets conditions and the ease of isolation of the corresponding allyl alcohols
Shear Viscosity to Entropy Density Ratio of QCD below the Deconfinement Temperature
Creators: name: Chen, Jiunn-Wei
name: Nakano, Eiji
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Using chiral perturbation theory we investigate the QCD shear viscosity to entropy density ratio below the deconfinement temperature (~170 MeV) with zero baryon number density. It is found that the viscosity to entropy density ratio of QCD is monotonically decreasing in temperature (T) and reaches 0.6 with estimated ~50% uncertainty at T=120 MeV. A naive extrapolation of the leading order result shows that the ratio reaches the 1/(4 pi) minimum bound proposed by Kovtun, Son, and Starinets using string theory methods at T~200 MeV. This suggests a phase transition or cross over might occur at T less than 200 MeV in order for the bound to remain valid. Also, it is natural for the ratio to stay close to the minimum bound around the phase transition temperature as was recently found in heavy ion collisions.
description: 12 pages and 2 figures
Exact solution of two simple non-equilibrium electron-phonon and electron-electron coupled systems: the atomic limit of the Holstein-Hubbard model and the generalized Hatsugai-Komoto model
Creators: name: Nesselrodt, R. D.
name: Freericks, J. K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: One of the challenges in many-body physics is determining the effects of phonons on strongly correlated electrons. The difficulty arises from strong correlations at differing energy scales -- for band metals, Migdal-Eliashberg theory accurately determines electron-phonon coupling effects due to the absence of vertex corrections -- but strongly correlated electrons require a more complex description and the standard Migdal-Eliashberg approach does not necessarily apply. In this work, we solve for the atomic limit Green's function of the Holstein-Hubbard model with both time-dependent electron-electron and electron-phonon couplings. We then examine the photoemission spectra (PES) of this model in and out of equilibrium. Next we use similar methods to exactly solve an extended version of the Hatsugai-Komoto model, and examine its behavior in and out of equilibrium. These calculations lead us to propose using the first moment of the photoemission spectra to signal non-equilibrium changes in electron-electron and electron-phonon couplings.
description: 7 pages (main text), 3 figures. (v2) corrects minor typos, (v3) extends the work, considers an additional model, adds references and supplemental material, and moves details of earlier version to appendix. To be published in Phys. Rev. B
Semantic and lexical elicitation: Modality and conversational items
Creators: name: Yegon, Kiplangat
name: Bossi, Madeline
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2022
Subjects: subject: sgc

description: One .mp4 file and one .pdf file. Elicitation of different certainty commitments across various epistemic modals. Elicitation of conversational items and discussion of spelling conventions.
Quantum-accelerated constraint programming
Creators: name: Booth, Kyle E. C.
name: O'Gorman, Bryan
name: Marshall, Jeffrey
name: Hadfield, Stuart
name: Rieffel, Eleanor
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Constraint programming (CP) is a paradigm used to model and solve constraint satisfaction and combinatorial optimization problems. In CP, problems are modeled with constraints that describe acceptable solutions and solved with backtracking tree search augmented with logical inference. In this paper, we show how quantum algorithms can accelerate CP, at both the levels of inference and search. Leveraging existing quantum algorithms, we introduce a quantum-accelerated filtering algorithm for the $\texttt{alldifferent}$ global constraint and discuss its applicability to a broader family of global constraints with similar structure. We propose frameworks for the integration of quantum filtering algorithms within both classical and quantum backtracking search schemes, including a novel hybrid classical-quantum backtracking search method. This work suggests that CP is a promising candidate application for early fault-tolerant quantum computers and beyond.
description: published in Quantum
Irradiance Variations of the Sun and Sun-Like Stars -- Overview of Topical Collection
Creators: name: Kopp, Greg
name: Shapiro, Alexander
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: This topical collection summarizes recent advances in observing and modeling irradiance variations of the Sun and Sun-like stars, emphasizing the links between surface magnetic fields and the resulting solar and stellar variability. In particular, the articles composing this collection summarize recent progress in i) solar-irradiance measurements; ii) modeling of solar- and stellar-irradiance variability; and iii) understanding of the effects of such variability on Earth's climate and exoplanet environments. This topical-collection overview article gives background and more details on these aspects of variability.
description: accepted for Solar Physics
Phase diagram of quark-antiquark and diquark condensates in the 3-dimensional Gross Neveu model with the 4-component spinor representation
Creators: name: Kohyama, Hiroaki
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We construct the phase diagram of the quark-antiquark and diquark condensates at finite temperature and density in the 2 + 1 dimensional (3D) two flavor massless Gross Neveu (GN) model with the 4-component quarks. In contrast to the case of the 2-component quarks, there appears the coexisting phase of the quark-antiquark and diquark condensates. This is the crucial difference between the 2-component and 4-component quark cases in the 3D GN model. The coexisting phase is also seen in the 4D Nambu Jona-Lasinio model. Then we see that the 3D GN model with the 4-component quarks bears closer resemblance to the 4D Nambu Jona-Lasinio model.
description: 11 pages, 3 figures, revtex
Reheating constraints on K-inflation
Creators: name: Pareek, Pooja
name: Nautiyal, Akhilesh
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we revisit constraints on K-inflation with DBI kinetic term and power-law kinetic term from reheating. For DBI kinetic term we choose monomial potentials, $V\propto ϕ^n$ with $n=2/3\,,1\,,\,2$ and $4$, and natural inflaton potential, and for power-law kinetic term we choose quadratic, quartic and exponential potentials. The phase of reheating can be parameterized in terms of reheating temperature $T_{re}$, number of e-folds during reheating $N_{re}$ and effective equation of state during reheating $w_{re}$. These parameters can be related to the spectral index $n_s$ and other inflationary parameters depending on the choice of inflaton kinetic term and potential. By demanding that $w_{re}$ should have a finite range and $T_{re}$ should be above electroweak scale, one can obtain the bounds on $n_s$ that can provide bounds on tensor-to-scalar ratio $r$. We find, for K-inflation with DBI kinetic term and quadratic and quartic potentials, that the upper bound on $r$ for physically plausible value of $0\le w_{re} \le 0.25$ is slightly larger than the Planck-2018 and BICEP2/Keck array bound, and for $n=2/3$ and $1$, the reheating equation of state should be less than $0$ to satisfy Planck-2018 joint constraints on $n_s$ and $r$. However, natural inflation with DBI kinetic term is compatible with Planck-2018 bounds on $r$ and joint constraints on $n_s$ and $r$ for physically plausible range $0 \le w_{re}\le 0.25$. The quadratic and quartic potential with power-law kinetic term are also compatible with Planck-2018 joint constraints on $n_s$ and $r$ for $0\le w_{re} \le 1$. However, for exponential potential with power-law kinetic term, the equation of state during reheating $w_{re}$ should be greater than $1$ for $r-n_s$ predictions to lie within $68\%$C.L. of joint constraints on $n_s$ and $r$ from Planck-2018 observations.
description: Version to appear in Physical Review D
Absolute molecular electronic spectroscopy at UV and soft X-Ray energies by hihg-energy electron impact
Creators: name: Burton, Gordon R.
Publisher: name: University of British Columbia
Year: 2008

description: Dipole (e,e) spectroscopy has been used to determine absolute photoabsorption oscillator strengths (cross sections) for electronic excitation of CC14, CH3OH, NH3, CH3NH2, (CH3)2NH, and (CH3)3N at energy resolutions in the range 0.048-1.0 eV fwhm. These data have been obtained in the valence, and inner shells (Cl 2p,2s; C is (CC14), and C is (CH3OH)), spanning the visible to soft X-ray equivalent photon energy regions(5.0-400 eV). Absolute scales have been established using the Thomas-Reiche-Kuhn sum rule. Dipole (e,e+ion) spectroscopy has been employed to study the molecular and dissociative photoionization in the valence shell of CH3OH, and in the valence and inner shells of CC14. Time-of-flight mass spectroscopy is used to determine photoionization branching ratios and photoionization efficiencies. These data are combined with the corresponding absolute photoabsorption oscillator strength data, to determine the partial oscillator strengths for the molecular and dissociative photoionization channels of these molecules. In addition, the measurements have been used to provide detailed quantitative information on the breakdown pathways of these molecules following the absorption of energetic radiation. The absolute photoabsorption measurements for ammonia and the methylamines have been used in a collaborative research project with Professor W.J. Meath, involving theoretical work at the University of Western Ontario. The results provide accurate values for many of the dipole properties of these nitrogen-containing molecules, as well as integrated dipole oscillator strength distributions for the entire photo absorption spectrum. In other work, a new high impact energy electron energy-loss spectrometer of high sensitivity has been designed and constructed. This instrument features an open scattering region, high incident electron beam energy, and multichannel detection, in order to measure absolute photo absorption oscillator strength data for not only stable atoms and molecules, but also for low-density targets including free radicals, ions, and laser-excited species.
Evidence for post-nebula volatilisation in an exo-planetary body
Creators: name: Harrison, John H. D.
name: Shorttle, Oliver
name: Bonsor, Amy
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The loss and gain of volatile elements during planet formation is key for setting their subsequent climate, geodynamics, and habitability. Two broad regimes of volatile element transport in and out of planetary building blocks have been identified: that occurring when the nebula is still present, and that occurring after it has dissipated. Evidence for volatile element loss in planetary bodies after the dissipation of the solar nebula is found in the high Mn to Na abundance ratio of Mars, the Moon, and many of the solar system's minor bodies. This volatile loss is expected to occur when the bodies are heated by planetary collisions and short-lived radionuclides, and enter a global magma ocean stage early in their history. The bulk composition of exo-planetary bodies can be determined by observing white dwarfs which have accreted planetary material. The abundances of Na, Mn, and Mg have been measured for the accreting material in four polluted white dwarf systems. Whilst the Mn/Na abundances of three white dwarf systems are consistent with the fractionations expected during nebula condensation, the high Mn/Na abundance ratio of GD362 means that it is not (>3 sigma). We find that heating of the planetary system orbiting GD362 during the star's giant branch evolution is insufficient to produce such a high Mn/Na. We, therefore, propose that volatile loss occurred in a manner analogous to that of the solar system bodies, either due to impacts shortly after their formation or from heating by short-lived radionuclides. We present potential evidence for a magma ocean stage on the exo-planetary body which currently pollutes the atmosphere of GD362.
How to Compute Invariant Manifolds and their Reduced Dynamics in High-Dimensional Finite-Element Models
Creators: name: Jain, Shobhit
name: Haller, George
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Dynamical Systems (math.DS)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Invariant manifolds are important constructs for the quantitative and qualitative understanding of nonlinear phenomena in dynamical systems. In nonlinear damped mechanical systems, for instance, spectral submanifolds have emerged as useful tools for the computation of forced response curves, backbone curves, detached resonance curves (isolas) via exact reduced-order models. For conservative nonlinear mechanical systems, Lyapunov subcenter manifolds and their reduced dynamics provide a way to identify nonlinear amplitude-frequency relationships in the form of conservative backbone curves. Despite these powerful predictions offered by invariant manifolds, their use has largely been limited to low-dimensional academic examples. This is because several challenges render their computation unfeasible for realistic engineering structures described by finite-element models. In this work, we address these computational challenges and develop methods for computing invariant manifolds and their reduced dynamics in very high-dimensional nonlinear systems arising from spatial discretization of the governing partial differential equations. We illustrate our computational algorithms on finite-element models of mechanical structures that range from a simple beam containing tens of degrees of freedom to an aircraft wing containing more than a hundred-thousand degrees of freedom.
Semantic elicitation: Modality and "think"
Creators: name: Kipkoech, Linus
name: Bossi, Madeline
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2022
Subjects: subject: sgc

description: One .m4a file and one .pdf file. Elicitation of different certainty commitments across various epistemic modals. Elicitation of negative bias towards presupposed and implicated content with pɑr vs. pwɑɑt.
Toxoplasma Life Cycle Group Activity
Creators: name: Vedrenne, Ana
Publisher: name: QUBES Educational Resources
Year: 2025

description: The Toxoplasma life cycle activity guides students in understanding 1) the generalized life cycle of apicomplexan parasites, 2) the transmission routes and risk factors associated with the parasite Toxoplasma gondii, and 3) how to read and interpret graphs related to parasitological data. The content has students reflect on the common misconception that correlation implies causation.

The activity involves 1) recalling prior knowledge about reproduction in apicomplexans, 2) matching steps of the life cycle with schematics, 3) reflections prompts to identify confusing points and brainstorm rules of organization, and 4) interpretation of a figure and table with parasitological data.
Multiple time scales and the empirical models for stochastic volatility
Creators: name: Buchbinder, G. L.
name: Chistilin, K. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Statistical Finance (q-fin.ST)
subject: FOS: Physical sciences
subject: FOS: Economics and business

description: The most common stochastic volatility models such as the Ornstein-Uhlenbeck (OU), the Heston, the exponential OU (ExpOU) and Hull-White models define volatility as a Markovian process. In this work we check of the applicability of the Markovian approximation at separate times scales and will try to answer the question which of the stochastic volatility models indicated above is the most realistic. To this end we consider the volatility at both short (a few days) and long (a few months)time scales as a Markovian process and estimate for it the coefficients of the Kramers-Moyal expansion using the data for Dow-Jones Index. It has been found that the empirical data allow to take only the first two coefficients of expansion to be non zero that define form of the volatility stochastic differential equation of Ito. It proved to be that for the long time scale the empirical data support the ExpOU model. At the short time scale the empirical model coincides with ExpOU model for the small volatility quantities only.
description: 19 pages, 6 figures
Learners’ profile of MOOC courses on Ancient Greek literature
Creators: name: Καραμανλή, Μαγδαληνή Ιωάννη
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Προφίλ μαθητών σε Μαζικά Διαδικτυακά Μαθήματα
MOOCs Αρχαίας Ελληνικής Φιλοσοφίας
Προθέσεις μαθητών
Learners’ profile of MOOCs
Ancient Greek Philosophy MOOCs
Learners’ intentions

description: Σκοπός της διατριβής ήταν η μελέτη των χαρακτηριστικών των συμμετεχόντων σε MOOC μαθήματα αρχαίας ελληνικής φιλοσοφίας καθώς και οι λόγοι για τους οποίους αποφάσισαν να παρακολουθήσουν τα μαθήματα αυτά. Πρόκειται για μια mixed method έρευνα, παρακολούθησης διαδικτυακών συνομιλιών (forum) 250 μαθητών. Στη μελέτη αυτή παρουσιάστηκε το προφίλ των συμμετεχόντων όπως το φύλο, η περιοχή και το μορφωτικό τους επίπεδο. Επιπλέον και από τα δυο forum προέκυψαν διαφορετικά είδη προθέσεων συμμετοχής των μαθητών στα MOOC αρχαία ελληνικής φιλοσοφίας
description: The aim of the present mixed method study was to investigate both students’ profile and intentions for enrolling in MOOC courses of Ancient Greek philosophy. Two forum observations were conducted in 250 students who participated in two courses of Ancient Greek Philosophy. The gender, the region and the educational background of the learners were presented in the research. Also, from both forums, different kinds of students‟ intentions were occurred
Finite size scaling for the core of large random hypergraphs
Creators: name: Dembo, Amir
name: Montanari, Andrea
Publisher: name: arXiv
Year: 2007
Subjects: subject: Probability (math.PR)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C80, 60J10, 60F17 (Primary) 68R10, 94A29 (Secondary)

description: The (two) core of a hypergraph is the maximal collection of hyperedges within which no vertex appears only once. It is of importance in tasks such as efficiently solving a large linear system over GF[2], or iterative decoding of low-density parity-check codes used over the binary erasure channel. Similar structures emerge in a variety of NP-hard combinatorial optimization and decision problems, from vertex cover to satisfiability. For a uniformly chosen random hypergraph of $m=nρ$ vertices and $n$ hyperedges, each consisting of the same fixed number $l\geq3$ of vertices, the size of the core exhibits for large $n$ a first-order phase transition, changing from $o(n)$ for $ρ>ρ_{\mathrm{c}}$ to a positive fraction of $n$ for $ρ0$. Analyzing the corresponding ``leaf removal'' algorithm, we determine the associated finite-size scaling behavior. In particular, if $ρ$ is inside the scaling window (more precisely, $ρ=ρ_{\mathrm{c}}+rn^{-1/2}$), the probability of having a core of size $Θ(n)$ has a limit strictly between 0 and 1, and a leading correction of order $Θ(n^{-1/6})$. The correction admits a sharp characterization in terms of the distribution of a Brownian motion with quadratic shift, from which it inherits the scaling with $n$. This behavior is expected to be universal for a wide collection of combinatorial problems.
description: Published in at http://dx.doi.org/10.1214/07-AAP514 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org)