cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A comparison of methods for finding magnetic nulls in simulations and in situ observations of space plasmas
Creators: name: Olshevsky, Vyacheslav
name: Pontin, David
name: Williams, Benjamin
name: Parnell, Clare
name: Fu, Huishan
name: Liu, Yangyang
name: Yao, Shutao
name: Khotyaintsev, Yuri
Publisher: name: arXiv
Year: 2021
Subjects: subject: Space Physics (physics.space-ph)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Magnetic nulls are ubiquitous in space plasmas, and are of interest as sites of localized energy dissipation or magnetic reconnection. As such, a number of methods have been proposed for detecting nulls in both simulation data and in situ spacecraft data from Earth's magnetosphere. The same methods can be applied to detect stagnation points in flow fields. In this paper we describe a systematic comparison of different methods for finding magnetic nulls. The Poincare index method, the first-order Taylor expansion (FOTE) method, and the trilinear method are considered. We define a magnetic field containing fourteen magnetic nulls whose positions and types are known to arbitrary precision. Furthermore, we applied the selected techniques in order to find and classify those nulls. Two situations are considered: one in which the magnetic field is discretized on a rectangular grid, and the second in which the magnetic field is discretized along synthetic `spacecraft trajectories' within the domain. At present, FOTE and trilinear are the most reliable methods for finding nulls in the spacecraft data and in numerical simulations on Cartesian grids, respectively. The Poincare index method is suitable for simulations on both tetrahedral and hexahedral meshes. The proposed magnetic field configuration can be used for grading and benchmarking the new and existing tools for finding magnetic nulls and flow stagnation points.
description: Reproduced with permission from Astronomy & Astrophysics, \c{opyright} ESO
Stars and gas in the very large interacting galaxy NGC 6872
Creators: name: Horellou, Cathy
name: Koribalski, Baerbel
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The dynamical evolution of the large (> 100 kpc), barred spiral galaxy NGC 6872 and its small companion IC 4970 in the southern group Pavo is investigated. We present N-body simulations with stars and gas and 21 cm HI observations carried out with the Australia Telescope Compact Array of the large-scale distribution and kinematics of atomic gas. HI is detected toward the companion, corresponding to a gas mass of ca 1.3 10^9 Msun. NGC 6872 contains ca 1.4 10^{10} Msun of HI gas, distributed in an extended rotating disk. Massive concentrations of gas (10^9 Msun) are found at the tip of both tidal tails and towards the break seen in the optical northern arm near the companion. We detect no HI counterpart to the X-ray trail between NGC 6872 and NGC 6876, the dominant elliptical galaxy in the Pavo group located 8 arcmin to the southeast. At the sensitivity and the resolution of the observations, there is no sign in the overall HI distribution that NGC 6876 has affected the evolution of NGC 6872. There is no evidence of ram pressure stripping either. The X-ray trail could be due to gravitational focusing of the hot gas in the Pavo group behind NGC 6872 as the galaxy moves supersonically through the hot medium. The simulations of a gravitational interaction with a small nearby companion on a low-inclination prograde passage are able to reproduce most of the observed features of NGC 6872, including the general morphology of the galaxy, the inner bar, the extent of the tidal tails and the thinness of the southern tail.
description: 12 pages, 11 figures. Accepted for publication in Astronomy & Astrophysics. The resolution of the figures has been greatly reduced. The paper with the original figures can found at http://www.oso.chalmers.se/~horellou/PAPERS/2006n6872.pdf
Muon spin rotation study of the magnetic penetration depth in the intercalated graphite superconductor CaC6
Creators: name: Di Castro, D.
name: Kanigel, A.
name: Maisuradze, A.
name: Keren, A.
name: Postorino, P.
name: Rosenmann, D.
name: Welp, U.
name: Karapetrov, G.
name: Claus, H.
name: Hinks, D. G.
name: Amato, A.
name: Campuzano, J. C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report temperature- and magnetic field-dependent bulk muon spin rotation measurements in a c-axis oriented superconductor CaC6 in the mixed state. Using both a simple second moment analysis and the more precise analytical Ginzburg-Landau model, we obtained a field independent in-plane magnetic penetration depth λab (0) = 72(3) nm. The temperature dependencies of the normalized muon spin relaxation rate and of the normalized superfluid density result to be identical, and both are well represented by the clean limit BCS model with 2Δ/kB Tc = 3.6(1), suggesting that CaC6 is a fully gapped BCS superconductor in the clean limit regime.
description: Accepted for publication in PRB
Efficient Anharmonic Lattice Dynamics Calculations of Thermal Transport in Crystalline and Disordered Solids
Creators: name: Barbalinardo, Giuseppe
name: Chen, Zekun
name: Lundgren, Nicholas W.
name: Donadio, Davide
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Understanding heat transport in semiconductors and insulators is of fundamental importance because of its technological impact in electronics and renewable energy harvesting and conversion. Anharmonic Lattice Dynamics provides a powerful framework for the description of heat transport at the nanoscale. One of the advantages of this method is that it naturally includes quantum effects due to atoms vibrations, which are needed to compute the thermal properties of semiconductors widely used in nanotechnology, like silicon and carbon, even at room temperature. While the heat transport picture substantially differs between amorphous and crystalline semiconductors from a microscopic standpoint, a unified approach to simulate both crystals and glasses has been devised. Here we introduce a unified workflow, which implements both the Boltzmann Transport equation (BTE) and the Quasi Harmonic Green-Kubo (QHGK) methods. We discuss how the theory can be optimized to exploit modern parallel architectures, and how it is implemented in $κALDo$: a versatile and scalable open-source software to compute phonon transport in solids. This approach is applied to crystalline and partially disordered silicon-based systems, including bulk silicon and clathrates, and on silicon-germanium alloy clathrates with largely reduced thermal conductivity.
description: 11 pages, 5 figures
Symplectic structure for general relativity and Einstein-Brillouin-Keller quantization
Creators: name: Kurihara, Yoshimasa
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The Hamiltonian system of general relativity and its quantization without any matter or gauge fields are discussed on the basis of the symplectic geometrical theory. A symplectic geometry of classical general relativity is constructed using a generalized phase space for pure gravity. Prequantization of the symplectic manifold is performed according to the standard procedure of geometrical quantization. Quantum vacuum solutions are chosen from among the classical solutions under the Einstein-Brillouin-Keller quantization condition. A topological correction of quantum solutions, namely the Maslov index, is realized using a prequantization bundle. In addition, a possible mass spectrum of Schwarzschild black holes is discussed.
description: 21 pages, no figure
Lorenz System Parameter Determination and Application to Break the Security of Two-channel Chaotic Cryptosystems
Creators: name: Orue, A. B.
name: Alvarez, G.
name: Romera, M.
name: Pastor, G.
name: Montoya, F.
name: Li, Shujun
Publisher: name: arXiv
Year: 2006
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: This paper describes how to determine the parameter values of the chaotic Lorenz system used in a two-channel cryptosystem. The geometrical properties of the Lorenz system are used firstly to reduce the parameter search space, then the parameters are exactly determined, directly from the ciphertext, through the minimization of the average jamming noise power created by the encryption process.
description: 5 pages, 5 figures Preprint submitted to IEEE T. Cas II, revision of authors name spelling
Constructing a qubit POVM from quantum data
Creators: name: Hillery, Mark
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Given an ensemble of qubits, which we are told consists of a mixture of two pure states, one with probability $η_{0}$ and one with probability $η_{1}$, we want to find a POVM that will discriminate between the two states by measuring the qubits. We do not know the states, and for any given qubit, we do not know which of the two states it is in. This can be viewed as learning a POVM from quantum data. Once found, the POVM can be used to separate the remaining qubits in the ensemble into two groups, corresponding to the two states present in the ensemble. In order to find the POVM, we need more information about the possible states. We examine several cases. First, we suppose that we know that the Bloch vectors of the states lie in the x-z plane and their \emph{a priori} probabilities are equal. We next keep the restriction to the x-z plane, but allow the \emph{a priori} probabilities to be different. Finally, we consider the case in which the Bloch vectors of the states have the same z component.
Photoluminescence of tetrahedral quantum-dot quantum wells
Creators: name: Fonoberov, V. A.
name: Pokatilov, E. P.
name: Fomin, V. M.
name: Devreese, J. T.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Taking into account the tetrahedral shape of a quantum dot quantum well (QDQW) when describing excitonic states, phonon modes and the exciton-phonon interaction in the structure, we obtain within a non-adiabatic approach a quantitative interpretation of the photoluminescence (PL) spectrum of a single CdS/HgS/CdS QDQW. We find that the exciton ground state in a tetrahedral QDQW is bright, in contrast to the dark ground state for a spherical QDQW.
description: 4 pages, 2 figures
Introducing KCWorks!
Creators: name: Babak, Larissa
name: Fitzpatrick, Kathleen
name: Russell, Bonnie
name: Scott, Ian
Publisher: name: unknown
Year: 2024
Subjects: subject: Open access
subject: National Endowment for the Humanities
subject: National Science Foundation (U.S.)

description: KCWorks is the next generation of the Knowledge Commons CORE repository. These slides were presented at a webinar held on Friday, November 15th to celebrate the launch of the public beta version of KCWorks. At the webinar, presenters highlighted the history of the projects, tips for getting started, some of the exciting new features of the system, and upcoming community programming.
Occupation time of a run-and-tumble particle with resetting
Creators: name: Bressloff, Paul C
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study the positive occupation time of a run-and-tumble particle (RTP) subject to stochastic resetting. Under the resetting protocol, the position of the particle is reset to the origin at a random sequence of times that is generated by a Poisson process with rate $r$. The velocity state is reset to $\pm v$ with fixed probabilities $ρ_1$ and $ρ_{-1}=1-ρ_1$, where $v$ is the speed. We exploit the fact that the moment generating functions with and without resetting are related by a renewal equation, and the latter generating function can be calculated by solving a corresponding Feynman-Kac equation. This allows us to numerically locate in Laplace space the largest real pole of the moment generating function with resetting, and thus derive a large deviation principle (LDP) for the occupation time probability density using the Gartner-Ellis theorem. We explore how the LDP depends on the switching rate $α$ of the velocity state, the resetting rate $r$ and the probability $ρ_1$. In particular, we show that the corresponding LDP for a Brownian particle with resetting is recovered in the fast switching limit $α\rightarrow \infty$. On the other hand, the behavior in the slow switching limit depends on $ρ_1$ in the resetting protocol.
description: 13 pages, 6 figures
Co-sponsorship analysis of party politics in the 20th National Assembly of Republic of Korea
Creators: name: Baek, Seung Ki
name: Kim, Jonghoon
name: Lee, Song Sub
name: Jo, Woo Seong
name: Kim, Beom Jun
Publisher: name: arXiv
Year: 2020
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: We investigate co-sponsorship among lawmakers by applying the principal-component analysis to the bills introduced in the 20th National Assembly of Korea. The most relevant factor for co-sponsorship is their party membership, and we clearly observe a signal of a third-party system in action. To identify other factors than the party influence, we analyze how lawmakers are clustered inside each party, and the result shows significant similarity between their committee membership and co-sponsorship in case of the ruling party. In addition, by monitoring each lawmaker's similarity to the average behavior of his or her party, we have found that it begins to decrease approximately one month before the lawmaker actually changes the party membership.
description: 19 pages, 6 figures
Infall of gas as the formation mechanism of stars up to 20 times more massive than the Sun
Creators: name: Beltran, Maria T.
name: Cesaroni, Riccardo
name: Codella, Claudio
name: Testi, Leonardo
name: Furuya, Ray S.
name: Olmi, Luca
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Theory predicts and observations confirm that low-mass stars (like the Sun) in their early life grow by accreting gas from the surrounding material. But for stars ~ 10 times more massive than the Sun (~10 M_sun), the powerful stellar radiation is expected to inhibit accretion and thus limit the growth of their mass. Clearly, stars with masses >10 M_sun exist, so there must be a way for them to form. The problem may be solved by non-spherical accretion, which allows some of the stellar photons to escape along the symmetry axis where the density is lower. The recent detection of rotating disks and toroids around very young massive stars has lent support to the idea that high-mass (> 8 M_sun) stars could form in this way. Here we report observations of an ammonia line towards a high-mass star forming region. We conclude from the data that the gas is falling inwards towards a very young star of ~20 M_sun, in line with theoretical predictions of non-spherical accretion.
description: 11 pages, 2 figures
Constructive Journalism in the Face of a Crisis: The Effects of Social Media News Updates About COVID-19
Creators: name: Overgaard, Christian Staal Bruun
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Science Policy
subject: 111714 Mental Health
subject: FOS: Health sciences

description: The COVID-19 pandemic brought along with it concerns about anxiety, racial bias, and pushback against public health recommendations, all of which are intensified by the news and social media. This study investigated the effects of constructive journalism in the context of this crisis, by randomly assigning 492 subjects to view simulated social media news updates with different headlines and images. The results showed positive and constructive headlines led to less anger and anxiety than negative headlines. The sanitization of graphic images decreased anger, anxiety, COVID-19 risk perceptions, and anti-Chinese sentiment—a relationship that was mediated by anger and anxiety. These findings suggest constructive journalism can be useful in times of crisis, and that its visual aspect warrants more scholarly attention. Further, these results shed new light on the effects of news exposure via social media in times of crisis, and how this impact depends on specific attributes of the headlines and images of the content being shared. The findings are discussed in relation to the theory of affective intelligence and recent concerns about how news and social media influence the public in times of crisis.
Pollux: A weak dynamo-driven dipolar magnetic field and implications for its probable planet
Creators: name: Aurière, M.
name: Petit, P.
name: Mathias, P.
name: Konstantinova-Antova, R.
name: Charbonnel, C.
name: Donati, J. -F.
name: Espagnet, O.
name: Folsom, C. P.
name: Roudier, T.
name: Wade, G. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Context: Pollux is considered as an archetype of a giant star hosting a planet. We then discovered a weak magnetic field at its surface using spectropolarimetry. Aims and Methods: We followed up our investigations on Pollux first using ESPaDOnS at CFHT and then Narval at TBL to obtain Stokes I and Stokes V spectra to study their variations for a duration of 4.25 years, that is, for more than two periods of about 590 d of the RV variations. We used the least-squares deconvolution (LSD) profiles to measure the longitudinal magnetic field and to perform a Zeeman Doppler imaging (ZDI) investigation. Results: The longitudinal magnetic field of Pollux is found to vary with a sinusoidal behavior and a period similar to that of the RV variations. From the ZDI investigation a rotation period of Pollux is determined to be equal to 660+/-15 days and possibly different than the period of variations of the RV. As to the magnetic topology, the poloidal component is dominant and almost purely dipolar with an inclination of 10.5° of the dipole with respect to the rotation axis. The mean strength of the surface magnetic field is 0.44 G. Conclusions: As to the origin of the magnetic field of Pollux, we favor the hypothesis that it is maintained through contemporaneous dynamo action. Pollux appears as the representative of a class of slowly rotating and weakly magnetic G-K red giants. To explain the sinusoidal RV variations of Pollux, two scenarios are proposed. If the RV period is different from the rotation period, the observed periodic RV variations are due to the hosted planet and the contribution of Pollux magnetic activity is not significantly detected. In the peculiar case in which the two periods are equal, we cannot discard the possibility that the activity of Pollux could explain the total RV variations and that the planet hypothesis would appear unnecessary.
description: 9 pages, 7 figures, accepted for publication in Astronomy & Astrophysics
Hubble Space Telescope Observations of SV Cam: I. The Importance of Unresolved Starspot Distributions in Lightcurve Fitting
Creators: name: Jeffers, S. V.
name: Barnes, J. R.
name: Cameron, A. Collier
name: Donati, J. -F.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have used maximum entropy eclipse mapping to recover images of the visual surface brightness distribution of the primary component of the RS CVn eclipsing binary SV Cam, using high-precision photometry data obtained during three primary eclipses with STIS aboard the Hubble Space Telescope. These were augmented by contemporaneous ground-based photometry secured around the rest of the orbit. The goal of these observations was to determine the filling factor and size distribution of starspots too small to be resolved by Doppler imaging. The information content of the final image and the fit to the data were optimised with respect to various system parameters using the chi^2 landscape method, using an eclipse mapping code that solves for large-scale spot coverage. It is only with the unprecedented photometric precision of the HST data (0.00015 mag) that it is possible to see strong discontinuities at the four contact points in the residuals of the fit to the lightcurve. These features can only be removed from the residual lightcurve by the reduction of the photospheric temperature, to synthesise high unresolvable spot coverage, and the inclusion of a polar spot. We show that this spottedness of the stellar surface can have a significant impact on the determination of the stellar binary parameters and the fit to the lightcurve by reducing the secondary radius from 0.794 +/- 0.009 Rsun to 0.727 +/- 0.009 Rsun. This new technique can also be applied to other binary systems with high precision spectrophotometric observations.
description: 9 pages, 10 figures
title: Έρευνα και ανάπτυξη οπλισμένης οπτοπλινθοδομής για την κατασκευή κτηρίων σε σεισμογενείς περιοχές
titleType: AlternativeTitle
title: Research and development of reinforced masonry for the construction of buldings in seismic regions
Creators: name: Stathatos, Alexandros P.
Publisher: name: National Technological University of Athens
Year: 2012
Subjects: Δομική μονάδα
Κονίαμα
Οπλισμός
Διάβρωση
Μηχανικές αντοχές
Δομικός σχεδιασμός
Brick
Mortar
Reinforcement
Corrosion
Mechanical resistance
Structural design

description: 451 σ.
description: Αντικείμενο της διδακτορικής διατριβής είναι η ανάπτυξη ενός συστήματος οπλισμένης τοιχοποιίας για την κατασκευή κτιρίων σε σεισμογενείς περιοχές. Προς τούτο ήταν απαραίτητος ο εξ αρχής σχεδιασμός μιας ή περισσοτέρων κεραμικών δομικών μονάδων, οι οποίες να επιτρέπουν την τοποθέτηση κατακόρυφου οπλισμού, να μπορούν να παραχθούν από τις Ελληνικές βιομηχανίες κεραμουργίας, και να καλύπτουν τις θερμομονωτικές απαιτήσεις του Ελληνικού Κανονισμού Θερμομονώσεως. Παράλληλα, επιλέχθηκαν και εξετάστηκαν κατάλληλες συνθέσεις κονιαμάτων δόμησης τα οποία να έχουν επαρκείς μηχανικές ιδιότητες (θλιπτική, καμπτική αντοχή, αντοχή συνάφειας) και να παρέχουν επαρκή προστασία έναντι διαβρώσεως, κυρίως του οριζόντιου οπλισμού. Ακόμη, μελετήθηκαν οι μηχανικές ιδιότητες των επί μέρους υλικών της τοιχοποιίας, καθώς και της ίδιας της τοιχοποιίας και τοίχων από οπλισμένη τοιχοποιία, μέσω εντός και εκτός του επιπέδου κατάλληλων πειραματικών δοκιμών. Τέλος, εξετάστηκαν και βελτιώθηκαν οι προτεινόμενες από τους Κανονισμούς και την βιβλιογραφία σχέσεις υπολογισμού της φέρουσας ικανότητας τοίχων από οπλισμένη τοιχοποιία σε εντός και εκτός επιπέδου δράσεις. Επιπρόσθετα, αναπτύχθηκαν δύο αναλυτικά προσομοιώματα πεπερασμένων στοιχείων για τη συμπεριφορά της τοιχοποιίας σε εκτός επιπέδου δράσεις, καλύπτοντας ουσιαστικά το κενό που υπάρχει στην βιβλιογραφία πάνω σε αυτό το αντικείμενο.
description: The subject of the thesis is the development of a masonry reinforced system for the construction of buildings in seismic regions. For this, it was necessary to design one or more bricks that would allow the placement of vertical reinforcement, that could be produced by the Hellenic brick factories and that would cover the thermal resistance requirements by the Hellenic Code of Thermal Insulation. In addition, mortar compositions with adequate mechanical characteristics (compression, flexural and bond strength) and that would provide sufficient corrosion resistance to the reinforcements, especially the bed-joint reinforcement were selected. Moreover, in plane and out of plane experimental tests were carried out in order to assess the mechanical properties of bricks, mortars and masonry. Further, existing Code and other researchers’ calculation expressions for the prediction of the in and out of plane resistance of reinforced masonry were calibrated and improved. Last but not least, two analytical finite element models for the out of plane behavior of reinforced masonry were developed, thus covering a practically under-researched field.
Correlations and fluctuations: generalized factorial moments
Creators: name: Bialas, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: A systematic study of the relations between fluctuations of the extensive multiparticle variables and integrals of the inclusive multipaticle densities is analysed. The generalized factorial moments are introduced and their physical meaning discussed. The effects of the additive conservation laws are analysed.
description: 18 pages
Preventive strikes on Nuclear facilities: an analytical framework
Creators: name: Herbst, Ludmila Barbara
Publisher: name: University of British Columbia
Year: 2009

description: Preventive strikes on nuclear facilities have been considered in perhaps ten cases since World War II. The continued proliferation of nuclear weapons means that there remains a variety of potential targets for preventive strikes, including countries such as Iran and Libya, launched by countries like the United States and Israel; this paper explores whether such military action against new weapons programs is in fact probable. The answer to this question is pursued through a comparison of the past cases where preventive strikes were under discussion. All share certain common features, but eight factors tend to distinguish instances where preventive strikes were carried out from the majority in which they were rejected. Significant support and little protest were expected when preventive strikes were engaged in. In turn, the prospect of operational success, defined in terms of destroying all relevant nuclear facilities in the target, was predictably worst where military action was not carried out. The degree and immediacy of threat were also depicted as more pronounced in the case of realized preventive strikes. Of course, perceptions of this kind are malleable; additional factors came into play. States which launched preventive strikes had few other options for dealing with the unwanted proliferator, and had the opportunity to destroy its nuclear facilities while they were still under construction (or, for other reasons, not in operation). With their eye on these kinds of factors, countries seemed to be deterred from undertaking military action when it would blatantly infringe upon international law. Furthermore, states were less inclined to act when faced with military retaliation by the target, and when, correspondingly, domestic public opinion promised to be unfavorable. Using this list of criteria for guidance, it will be concluded that preventive strikes are unlikely to occur in the near future.
Course materials for Quantifying Environmental Justice
Creators: name: Jones, Jabari
Publisher: name: QUBES Educational Resources
Year: 2024

description: Course materials for Quantifying Environmental Justice, taught as Environmental Science 4201 at University of Minnesota, Morris in Spring 2023. Description:
The concept of justice has received increasing attention in environmental fields in recent years, particularly since the murder of George Floyd in May 2020. But the field of Environmental Justice has existed since the late 1970s, when black communities were fighting the siting of toxic facilities in their neighborhoods. In spite of this, environmental students often leave college without a strong foundation to address questions of justice.

In this course, we will take a data-driven approach to questions of justice. How is justice defined and measured? What data is available to evaluate questions of justice? What skills do we need to answer these questions? We will attempt to answer those questions through readings in classic and contemporary environmental justice, lab exercises to develop statistical and geographical skills, and an intensive case study to apply our thoughts and skills to real-world questions.
Internal Language Model Estimation for Domain-Adaptive End-to-End Speech Recognition
Creators: name: Meng, Zhong
name: Parthasarathy, Sarangarajan
name: Sun, Eric
name: Gaur, Yashesh
name: Kanda, Naoyuki
name: Lu, Liang
name: Chen, Xie
name: Zhao, Rui
name: Li, Jinyu
name: Gong, Yifan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Audio and Speech Processing (eess.AS)
subject: Computation and Language (cs.CL)
subject: Machine Learning (cs.LG)
subject: Sound (cs.SD)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: The external language models (LM) integration remains a challenging task for end-to-end (E2E) automatic speech recognition (ASR) which has no clear division between acoustic and language models. In this work, we propose an internal LM estimation (ILME) method to facilitate a more effective integration of the external LM with all pre-existing E2E models with no additional model training, including the most popular recurrent neural network transducer (RNN-T) and attention-based encoder-decoder (AED) models. Trained with audio-transcript pairs, an E2E model implicitly learns an internal LM that characterizes the training data in the source domain. With ILME, the internal LM scores of an E2E model are estimated and subtracted from the log-linear interpolation between the scores of the E2E model and the external LM. The internal LM scores are approximated as the output of an E2E model when eliminating its acoustic components. ILME can alleviate the domain mismatch between training and testing, or improve the multi-domain E2E ASR. Experimented with 30K-hour trained RNN-T and AED models, ILME achieves up to 15.5% and 6.8% relative word error rate reductions from Shallow Fusion on out-of-domain LibriSpeech and in-domain Microsoft production test sets, respectively.
description: 8 pages, 2 figures, SLT 2021
Robust control of quantum systems by quantum systems
Creators: name: Konrad, Thomas
name: Rouillard, Amy
name: Kastner, Michael
name: Uys, Hermann
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum systems can be controlled by other quantum systems in a reversible way, without any information leaking to the outside of the system-controller compound. Such coherent quantum control is deterministic, is less noisy than measurement-based feedback control, and has potential applications in a variety of quantum technologies, including quantum computation, quantum communication and quantum metrology. Here we introduce a coherent feedback protocol, consisting of a sequence of identical interactions with controlling quantum systems, that steers a quantum system from an arbitrary initial state towards a target state. We determine the broad class of such coherent feedback channels that achieve convergence to the target state, and then stabilise as well as protect it against noise. Our results imply that also weak system-controller interactions can counter noise if they occur with suitably high frequency. We provide an example of a control scheme that does not require knowledge of the target state encoded in the controllers, which could be the result of a quantum computation. It thus provides a mechanism for autonomous, purely quantum closed-loop control.
Small-signal parameters extraction and noise analysis of CNTFETs
Creators: name: Ramos-Silva, Javier N.
name: Pacheco-Sánchez, Aníbal
name: Enciso-Aguilar, Mauro A.
name: Jiménez, David
name: Ramírez-García, Eloy
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The use of carbon nanotube (CNT) field-effect transistors (FETs) in microwave circuit design requires an appropriate, immediate and efficient description of their performance. This work describes a technique to extract the parameters of an electrical equivalent circuit for CNTFETs. The equivalent circuit is used to model the dynamic and noise performance at low- and high-frequency of different CNTFET technologies, considering extrinsic and intrinsic device parameters as well as the contact resistance. The estimation of the contact resistance at the metal/CNTs interfaces is obtained from a Y-function based extraction method. The noise model includes four noise sources: thermal noise, thermal channel noise, shot channel noise and flicker noise. The proposed model is compared with a compact model calibrated to hysteresis-free experimental data from a high-frequency multi-tube (MT)-CNTFET technology. Additionally, it has been applied to experimental data from another fabricated MT-CNTFET technology. The comparison in both cases shows a good agreement between reference data (simulation and experimental) and results from the proposed model. Low- and high-frequency noise projections of the fabricated reference device are further studied. Noise results from both studied technologies show that shot noise mainly contributes to the total noise due to the presence of Schottky barriers at contacts and along the channel.
Monolithic bowtie cavity traps for ultra-cold gases
Creators: name: Cai, Yanping
name: Allman, Daniel
name: Evans, Jesse
name: Sabharwal, Parth
name: Wright, Kevin C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report on trapping and cooling Li-6 atoms in a monolithic ring bowtie cavity. To make the cavity insensitive to magnetic fields used to tune atomic interactions, we constructed it entirely from fused silica and Zerodur. The components were assembled using hydroxide bonding, which we show can be compatible with ultra-high vacuum. Backscattering in high-finesse ring cavities readily causes trap intensity fluctuations and heating, but with phase-controlled bi-directional pumping the trap lifetime can be made long enough for quantum gas experiments in both the crossed-beam trap (unidirectional pump) and 2D lattice trap (bidirectional pump) configurations.
description: 15 pages, 5 figures To be published JOSA B Nov. 2020
Hall effect measurements on YbRh2Si2 and relatives in the light of electronic structure calculations
Creators: name: Friedemann, S.
name: Oeschler, N.
name: Wirth, S.
name: Krellner, C.
name: Geibel, C.
name: Steglich, F.
name: MaQuilon, S.
name: Fisk, Z.
name: Paschen, S.
name: Zwicknagl, G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report experimental and theoretical investigations of the Hall effect in YbRh2Si2 and its reference compounds LuRh2Si2 and YbIr2Si2. Based on band-structure calculations we identify two bands dominating the Hall coefficient in all these compounds. For the case of LuRh2Si2 - the non-magnetic reference compound of YbRh2Si2 - the temperature dependence of the Hall coefficient is described quantitatively to arise from two hole-like bands. For YbIr2Si2 and YbRh2Si2, renormalized band calculations yield two bands of opposite character. In YbRh2Si2 these two bands almost compensate each other. We present strong indications that the sample dependences of the low-temperature Hall coefficient observed for YbRh2Si2 arise from slight variations of the relative scattering rates of the two bands. Minute changes of the composition appear to be the origin.
description: 12 pages, 8 figures
Effect of strain-induced orbital splitting on the magnetic excitations in undoped cuprates
Creators: name: Singh, Dheeraj Kumar
name: Bang, Yunkyu
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate the magnetic excitations in view of the recent reports suggesting that the spin-wave energy may exhibit a significant dependence on the in-plane strain of a thin film of La$_2$CuO$_4$. The nature of dependence, as we find, can be explained naturally within a two-orbital model based on the $d_{x^2-y^2}$ and $d_{3z^2-r^2}$ orbitals. In particular, as the orbital-splitting energy between the $d_{x^2-y^2}$ and $d_{3z^2-r^2}$ orbitals increases with compressive strain, the zone-boundary spin-wave energy hardens. However, the hardening persists only until the orbital splitting reaches $\sim$ 2eV, beyond which there is no significant change. The behavior of zone-boundary spin-wave energy is explained in terms of the extent of hybridization between one of the exchange-split $d_{x^2-y^2}$ band which is nearly half filled and the $d_{3z^2-r^2}$ band. The role of second-order antiferromagnetic superexchange process involving the inter-orbital hopping is also discussed.
description: 6 pages, 5 figures
The experience of caring for a child with a medically-fragile condiction at home: perceptions of parents
Creators: name: Cender, Loryle Marie
Publisher: name: University of British Columbia
Year: 2009

description: This study was designed to discover and describe the experiences of parents who care for their child with a medically-fragile condition at home. The qualitative method of phenomenology was employed to elicit an understanding of the parents' experiences. Data collection occurred through indepth interviews with six mothers and three fathers of six children who had a wide range of medically-fragile conditions and who were receiving in-home nursing respite support. Through a process of ongoing data collection and simultaneous data analysis, the experiences of the participants were described. Parents' experiences of caring for their child with a medically-fragile condition were conceptualized as evolving through three critical time periods: hospital-based care, transition from hospital to home-based care, and home-based care. In addition, the parents' descriptions of becoming their child's primary caregiver were conceptualized as progressing through four distinct stages across the time frame of these three critical periods. In particular, the characteristics of supportive and conflictual parent - health care provider relationships were highlighted as an important element of the participants' experiences. The description and analysis of these components of the parents' experience provided the foundation for the analysis of the dynamics of parental caregiving for a child with a medically-fragile condition at home. The dynamics of parental caregiving were conceptualized as a process of balancing the nature of caregiving demands with the nature of parental caregiving. The inherently fragile nature of the child's condition played a key role in the unique experiences of these families. Concepts central to understanding the participants' experience were discussed in relation to existing literature in this area. Implications for nursing practice, education and research were examined.
Calculation of beta-decay rates in a relativistic model with momentum-dependent self-energies
Creators: name: Marketin, T.
name: Vretenar, D.
name: Ring, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is applied in the calculation of beta-decay half-lives of neutron-rich nuclei in the $Z\approx 28$ and $Z\approx 50$ regions. The study is based on the relativistic Hartree-Bogoliubov calculation of nuclear ground-states, using effective Lagrangians with density-dependent meson-nucleon couplings, and also extended by the inclusion of couplings between the isoscalar meson fields and the derivatives of the nucleon fields. This leads to a linear momentum dependence of the scalar and vector nucleon self-energies. The residual QRPA interaction in the particle-hole channel includes the $π+ ρ$ exchange plus a Landau-Migdal term. The finite-range Gogny interaction is employed in the T=1 pairing channel, and the model also includes a proton-neutron particle-particle interaction. The results are compared with available data, and it is shown that an extension of the standard relativistic mean-field framework to include momentum-dependent nucleon self-energies naturally leads to an enhancement of the effective (Landau) nucleon mass, and thus to an improved PN-QRPA description of beta-decay rates.
description: 16 pages, 3 figures, submitted to Physical Review C
Structural evolution in massive galaxies at z~2
Creators: name: Tadaki, Ken-ichi
name: Belli, Sirio
name: Burkert, Andreas
name: Dekel, Avishai
name: Schreiber, Natascha M. Förster
name: Genzel, Reinhard
name: Hayashi, Masao
name: Herrera-Camus, Rodrigo
name: Kodama, Tadayuki
name: Kohno, Kotaro
name: Koyama, Yusei
name: Lee, Minju M.
name: Lutz, Dieter
name: Mowla, Lamiya
name: Nelson, Erica J.
name: Renzini, Alvio
name: Suzuki, Tomoko L.
name: Tacconi, Linda J.
name: Übler, Hannah
name: Wisnioski, Emily
name: Wuyts, Stijn
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present 0.2arcsec-resolution Atacama Large Millimeter/submillimeter Array observations at 870 $μ$m in a stellar mass-selected sample of 85 massive ($M_\mathrm{star}>10^{11}~M_\odot$) star-forming galaxies (SFGs) at z=1.9-2.6 in the 3D-HST/CANDELS fields of UDS and GOODS-S. We measure the effective radius of the rest-frame far-infrared (FIR) emission for 62 massive SFGs. They are distributed over wide ranges of FIR size from $R_\mathrm{e,FIR}=$0.4 kpc to $R_\mathrm{e,FIR}=$6 kpc. The effective radius of the FIR emission is smaller by a factor of 2.3$^{+1.9}_{-1.0}$ than the effective radius of the optical emission and by a factor of 1.9$^{+1.9}_{-1.0}$ smaller than the half-mass radius. Even with taking into account potential extended components, the FIR size would change by ~10%. By combining the spatial distributions of the FIR and optical emission, we investigate how galaxies change the effective radius of the optical emission and the stellar mass within a radius of 1 kpc, $M_\mathrm{1kpc}$. The compact starburst puts most of massive SFGs on the mass--size relation for quiescent galaxies (QGs) at z~2 within 300 Myr if the current star formation activity and its spatial distribution are maintained. We also find that within 300 Myr, ~38% of massive SFGs can reach the central mass of $M_\mathrm{1kpc}=10^{10.5}~M_\odot$, which is around the boundary between massive SFGs and QGs. These results suggest an outside-in transformation scenario in which a dense core is formed at the center of a more extended disk, likely via dissipative in-disk inflows. Synchronized observations at ALMA 870 $μ$m and JWST 3-4 $μ$m will explicitly verify this scenario.
description: 25 pages, 15 figures, 3 tables, accepted for publication in ApJ
Cationic exchange in nanosized ZnFe2O4 spinel revealed by experimental and simulated near-edge absorption structure
Creators: name: Stewart, S. J.
name: Figueroa, S. J. A.
name: Ramallo-López, J. M.
name: Marchetti, S. G.
name: Bengoa, J. F.
name: Prado, R. J.
name: Requejo, F. G.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The non-equilibrium cation site occupancy in nanosized zinc ferrites (6-13 nm) with different degree of inversion (0.2 to 0.4) was investigated using Fe and Zn K-edge x-ray absorption spectroscopy XANES and EXAFS, and magnetic measurements. The very good agreement between experimental and ab-initio calculations on the Zn K-edge XANES region clearly show the large Zn2+(A)--Zn2+[B] transference that takes place in addition to the well-identified Fe3+[B]--Fe3+(A) one, without altering the long-range structural order. XANES spectra features as a function of the spinel inversion were shown to depend on the configuration of the ligand shells surrounding the absorbing atom. This XANES approach provides a direct way to sense cationic inversion in these spinel compounds. We also demonstrated that a mechanical crystallization takes place on nanocrystalline spinel that causes an increase of both grain and magnetic sizes and, simultaneously, generates a significant augment of the inversion.
description: 5 pages, 5 eps figures, uses revtex4, corrected tables
DUG-RECON: A Framework for Direct Image Reconstruction using Convolutional Generative Networks
Creators: name: Kandarpa, V. S. S.
name: Bousse, Alexandre
name: Benoit, Didier
name: Visvikis, Dimitris
Publisher: name: arXiv
Year: 2020
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: This paper explores convolutional generative networks as an alternative to iterative reconstruction algorithms in medical image reconstruction. The task of medical image reconstruction involves mapping of projection main data collected from the detector to the image domain. This mapping is done typically through iterative reconstruction algorithms which are time consuming and computationally expensive. Trained deep learning networks provide faster outputs as proven in various tasks across computer vision. In this work we propose a direct reconstruction framework exclusively with deep learning architectures. The proposed framework consists of three segments, namely denoising, reconstruction and super resolution. The denoising and the super resolution segments act as processing steps. The reconstruction segment consists of a novel double U-Net generator (DUG) which learns the sinogram-to-image transformation. This entire network was trained on positron emission tomography (PET) and computed tomography (CT) images. The reconstruction framework approximates two-dimensional (2-D) mapping from projection domain to image domain. The architecture proposed in this proof-of-concept work is a novel approach to direct image reconstruction; further improvement is required to implement it in a clinical setting.
description: The code associated with the paper can be found at https://github.com/sai-sundar/DUG-RECON.git
State sum construction of two-dimensional open-closed Topological Quantum Field Theories
Creators: name: Lauda, Aaron D.
name: Pfeiffer, Hendryk
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Algebra (math.QA)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 57R56, 57M99, 81T40, 57Q20

description: We present a state sum construction of two-dimensional extended Topological Quantum Field Theories (TQFTs), so-called open-closed TQFTs, which generalizes the state sum of Fukuma--Hosono--Kawai from triangulations of conventional two-dimensional cobordisms to those of open-closed cobordisms, i.e. smooth compact oriented 2-manifolds with corners that have a particular global structure. This construction reveals the topological interpretation of the associative algebra on which the state sum is based, as the vector space that the TQFT assigns to the unit interval. Extending the notion of a two-dimensional TQFT from cobordisms to suitable manifolds with corners therefore makes the relationship between the global description of the TQFT in terms of a functor into the category of vector spaces and the local description in terms of a state sum fully transparent. We also illustrate the state sum construction of an open-closed TQFT with a finite set of D-branes using the example of the groupoid algebra of a finite groupoid.
description: 33 pages; LaTeX2e with xypic and pstricks macros; v2: typos corrected