cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Publication Patterns' Changes due to the COVID-19 Pandemic: A longitudinal and short-term scientometric analysis
Creators: name: Aviv-Reuven, Shir
name: Rosenfeld, Ariel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Digital Libraries (cs.DL)
subject: FOS: Computer and information sciences

description: In recent months the COVID-19 (also known as SARS-CoV-2 and Coronavirus) pandemic has spread throughout the world. In parallel, extensive scholarly research regarding various aspects of the pandemic has been published. In this work, we analyse the changes in biomedical publishing patterns due to the pandemic. We study the changes in the volume of publications in both peer reviewed journals and preprint servers, average time to acceptance of papers submitted to biomedical journals, international (co-)authorship of these papers (expressed by diversity and volume), and the possible association between journal metrics and said changes. We study these possible changes using two approaches: a short-term analysis through which changes during the first six months of the outbreak are examined for both COVID-19 related papers and non-COVID-19 related papers; and a longitudinal approach through which changes are examined in comparison to the previous four years. Our results show that the pandemic has so far had a tremendous effect on all examined accounts of scholarly publications: A sharp increase in publication volume has been witnessed and it can be almost entirely attributed to the pandemic; a significantly faster mean time to acceptance for COVID-19 papers is apparent, and it has (partially) come at the expense of non-COVID-19 papers; and a significant reduction in international collaboration for COVID-19 papers has also been identified. As the pandemic continues to spread, these changes may cause a slow down in research in non-COVID-19 biomedical fields and bring about a lower rate of international collaboration.
description: 26 pages, 9 figures, 11 tables
Ford Highway Driving RTK Dataset: 30,000 km of North American Highways
Creators: name: Houts, Sarah E.
name: Pervez, Nahid
name: Ibrahim, Umair
name: Pandey, Gaurav
name: Reid, Tyler G. R.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Signal Processing (eess.SP)
subject: Robotics (cs.RO)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: There is a growing need for vehicle positioning information to support Advanced Driver Assistance Systems (ADAS), Connectivity (V2X), and Autonomous Driving (AD) features. These range from a need for road determination ($<$5 meters), lane determination ($<$1.5 meters), and determining where the vehicle is within the lane ($<$0.3 meters). This paper presents the Ford Highway Driving RTK (Ford-HDR) dataset. This dataset includes nearly 30,000 km of data collected primarily on North American highways during a driving campaign designed to validate driver assistance features in 2018. This includes data from a representative automotive production GNSS used primarily for turn-by-turn navigation as well as an Inertial Navigation System (INS) which couples two survey-grade GNSS receivers with a tactical grade Inertial Measurement Unit (IMU) to act as ground truth. The latter utilized networked Real-Time Kinematic (RTK) GNSS corrections delivered over a cellular modem in real-time. This dataset is being released into the public domain to spark further research in the community.
description: 8 pages, 4 figures, ION GNSS+ 2020
The study of diffuse interface propagation of dynamic failure in advanced ceramics using the phase-field approach
Creators: Amirian, Benhour
Abali, Bilen Emek
Hogan, James D.
Publisher: name: University of Alberta Library
Year: 2023

Dynamic failure in advanced ceramic materials is a complex mechanical phenomenon, which is challenging to study in experimental and computational works. This work models and investigates the crack initiation, growth, propagation, and branching in two-dimensional single crystalline boron carbide at the nanometer length-scale and picosecond time-scale. A phase-field approach is used by carefully selecting the interfacial energy allowing a monolithic numerical solution method capturing strong coupling between mechanics and damage. Specifically, the transient Ginzburg–Landau equation is coupled with the balance of momentum including geometric nonlinearities and solved by using the open-source computing platform FEniCS. The monolithic computation ensures necessary accuracy for dynamic fracture under pure mode I loading, and also demonstrates the capability of crack branching depending on the loading rate. The effect of crack regularization length and kinetic coefficient on the crack interface profile and crack tip velocity is also studied. Altogether, the results are important for modeling anisotropic fracture in advanced ceramics and designing materials with desired dynamic failure characteristics.
Zero-shot Entity Linking with Efficient Long Range Sequence Modeling
Creators: name: Yao, Zonghai
name: Cao, Liangliang
name: Pan, Huapu
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computation and Language (cs.CL)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: This paper considers the problem of zero-shot entity linking, in which a link in the test time may not present in training. Following the prevailing BERT-based research efforts, we find a simple yet effective way is to expand the long-range sequence modeling. Unlike many previous methods, our method does not require expensive pre-training of BERT with long position embedding. Instead, we propose an efficient position embeddings initialization method called Embedding-repeat, which initializes larger position embeddings based on BERT-Base. On Wikia's zero-shot EL dataset, our method improves the SOTA from 76.06% to 79.08%, and for its long data, the corresponding improvement is from 74.57% to 82.14%. Our experiments suggest the effectiveness of long-range sequence modeling without retraining the BERT model.
description: 6 pages, 6 figures, Findings of EMNLP2020
FRILL: A Non-Semantic Speech Embedding for Mobile Devices
Creators: name: Peplinski, Jacob
name: Shor, Joel
name: Joglekar, Sachin
name: Garrison, Jake
name: Patel, Shwetak
Publisher: name: arXiv
Year: 2020
Subjects: subject: Sound (cs.SD)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Learned speech representations can drastically improve performance on tasks with limited labeled data. However, due to their size and complexity, learned representations have limited utility in mobile settings where run-time performance can be a significant bottleneck. In this work, we propose a class of lightweight non-semantic speech embedding models that run efficiently on mobile devices based on the recently proposed TRILL speech embedding. We combine novel architectural modifications with existing speed-up techniques to create embedding models that are fast enough to run in real-time on a mobile device and exhibit minimal performance degradation on a benchmark of non-semantic speech tasks. One such model (FRILL) is 32x faster on a Pixel 1 smartphone and 40% the size of TRILL, with an average decrease in accuracy of only 2%. To our knowledge, FRILL is the highest-quality non-semantic embedding designed for use on mobile devices. Furthermore, we demonstrate that these representations are useful for mobile health tasks such as non-speech human sounds detection and face-masked speech detection. Our models and code are publicly available.
description: Accepted to Interspeech 2021
Coffee Lecture Slides: "Verschlüsselung von Dateien und Ordnern" (Coffee Lecture: 24.01.2024)
Creators: name: Kirsch, Stefan
Publisher: name: Zenodo
Year: 2024
Subjects: FDM
rdm
Forschungsdatenmanagement
research data management
Verschlüsselung
encryption
Veracrypt
Cryptomator
Coffee Lecture

description: English: Coffee Lecture Slides:  "Tools for encrypting files and folders" (Coffee Lecture: 24 jan 2024)

A large part of the data we use on a daily basis, is not meant to be shared unconditionally.

Encrypting files and folders is a simple way to restrict access to data - whether it is passwords or sensitive business information. In an educational or university context this might be project accounting records to be stored in the cloud, on a USB stick or an external hard drive, or the need to adequately protect personal data collected in one's own research from unauthorized access.

There are tools making encryption suitable for everyday use and much easier than is often assumed which we will introduce in this talk.including a closer look at Veracrypt and Cryptomator.

Video in German: Link

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Coffee Lecture Folien: "Verschlüsselung von Dateien und Ordnern" (Coffee Lecture: 24.01.2024)

Unter den vielen Daten, mit denen jede und jeder von uns täglich Berührung hat, sind etliche, die nicht für die Einsicht oder Kenntnis durch beliebige Personen bestimmt sind.Die Verschlüsselung von Dateien und Ordnern ist eine einfache Methode, den Zugriff auf Daten zu beschränken - egal ob es sich um Zugangsdaten oder andere Geheimnisse handelt, um Unterlagen aus der Projektbuchhaltung, die in der Cloud, auf USB-Stick oder externer Festplatte gespeichert werden sollen oder ob es um das Erfordernis geht, in der eigenen Forschung erhobene personenbezogene Daten angemessen vor unbefugtem Zugriff zu schützen.Es gibt Werkzeuge, mit denen diese Verschlüsselung alltagstauglich und viel einfacher zu bewerkstelligen ist, als oft vermutet.

Die Softwaretools Veracrypt und Cryptomator werden etwas näher betrachtet.  

Video: Link
The (eighteenth century) enclosures of the townships of (Sutton) Bonington St Michael's and Sutton St Anne's, in the County of Nottingham: an attempt at an analysis
Creators: name: Tate, W
name: Mant, A
name: Birkett, N
Publisher: name: Archaeology Data Service
Year: 2023

description: Transactions of the Thoroton Society, 34, 133-150
Two-dimensional wave propagation without anomalous dispersion
Creators: name: Bender, Carl M.
name: Rodriguez, Francisco J.
name: Sarkar, Sarben
name: Zayats, Anatoly V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: In two space dimensions and one time dimension a wave changes its shape even in the absence of a dispersive medium. However, this anomalous dispersive behavior in empty two-dimensional space does not occur if the wave dynamics is described by a linear homogeneous wave equation in two space dimensions and {\it two} time dimensions. Wave propagation in such a space can be realized in a three-dimensional anisotropic metamaterial in which one of the space dimensions has a negative permittivity and thus serves as an effective second time dimension. These results lead to a fundamental understanding and new approaches to ultrashort pulse shaping in nanostructures and metamaterials.
Exceptional Bound States and negative Entanglement Entropy
Creators: name: Lee, Ching Hua
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Physics (physics.comp-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: This work introduces a new class of robust states known as Exceptional Boundary (EB) states, which are distinct from the well-known topological and non-Hermitian skin boundary states. EB states occur in the presence of exceptional points, which are non-Hermitian critical points where eigenstates coalesce and fail to span the Hilbert space. This eigenspace defectiveness not only limits the accessibility of state information, but also interplays with long-range order to give rise to singular propagators only possible in non-Hermitian settings. Their resultant EB eigenstates are characterized by robust anomalously large or negative occupation probabilities, unlike ordinary Fermi sea states whose probabilities lie between zero and one. EB states remain robust after a variety of quantum quenches and give rise to enigmatic negative entanglement entropy contributions. Through suitable perturbations, the coefficient of the logarithmic entanglement entropy scaling can be continuously tuned. EB states represent a new avenue for robustness arising from geometric defectiveness, independent of topological protection or non-reciprocal pumping.
description: 21 pages, 8 figures, 1 table
Anisotropic Ejection from Active Asteroid P/2010 A2: An Implication of Impact Shattering on an Asteroid
Creators: name: Kim, Yoonyoung
name: Ishiguro, Masateru
name: Michikami, Tatsuhiro
name: Nakamura, Akiko M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We revisited a mass ejection phenomenon that occurred in asteroid P/2010 A2 in terms of the dynamical properties of the dust particles and large fragments. We constructed a model assuming anisotropic ejection within a solid cone-shaped jet and succeeded in reproducing the time-variant features in archival observational images over ~3 years from 2010 January to 2012 October. When we assumed that the dust particles and fragments were ejected in the same direction from a point where no object had been detected in any observations, the anisotropic model can explain all of the observations including (i) the unique dust cloud morphology, (ii) the trail surface brightness and (iii) the motions of the fragments. Our results suggest that the original body was shattered by an impact with the specific energy of Q*
description: accepted for publication in The Astronomical Journal
Universal Peaks Ratio In The Spectral Energy Density Of Double Hump Blazars, Gamma Ray Bursts, And Microquasars
Creators: name: Dado, Shlomo
name: Dar, Arnon
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The peak frequencies of the two broad humps evident in the spectral energy density of blazars (SED) are time dependent and vary a lot between different blazars. However, their ratio in most blazars, appears to be almost universal and equal to $m_e c^2/4(1+z) ε_p$ to a good approximation, where $m_e$ is the electron mass, $ε_p$ is the peak energy of the cosmic microwave background radiation, and $z$ is the redshift of the blazar. We discuss a possible origin of such a universal ratio in blazars and gamma ray bursts (GRBs). We point out a possible connection between the knee in the energy spectrum of cosmic ray electrons and the maximal peak energies of the two broad humps in the SED of high-energy peaked blazars.
description: Accepted for publication in ApJL
Oscillatory patterns along the entire septo-temporal axis of the hippocampus in behaving rats
Creators: name: Patel, Jagdish
Publisher: name: No Publisher Supplied
Year: 2013

description: The hippocampus exhibits two major modes of activity: Theta oscillations during the “online” active behavior and sharp-wave associated ripples during the “offline” inactive state. The rodent hippocampus is a complex C- shaped structure with a longitudinal axis (LA) of approximately 10mm. While theta and ripples oscillations have been extensively studied over the last 4 decades with strong evidence of their role in hippocampal memory functions, the organization of these oscillatory patterns along the LA has never been studied before. This lacuna is striking because there are genomic, anatomic, cellular, synaptic, and functional differences along its LA. My dissertation investigated the organization of theta (5-10Hz) and sharp wave associated ripple (140 -200Hz) oscillations along the entire LA of the hippocampus in behaving rats. Using multiple drives I simultaneously recorded local field potentials and single unit activity from multiple locations along the LA. The first study examined traveling theta waves. While the frequency of theta oscillations remained similar, theta amplitude and coherence between recording sites decreased from the dorsal to the ventral hippocampus. Theta phase shifted monotonically along the LA, reaching a maximum of 180o. While the majority of single units were phase-locked to the local field at all dorso-ventral segments, approximately 25% of single units from the ventral segment were phase locked to the dorsal hippocampal theta. Ventral hippocampal theta was weakly correlated with the locomotion velocity and varied independently of dorsal hippocampal theta. Thus, theta oscillations can temporally integrate or segregate neocortical representations along the LA of the hippocampus. The second study examined the local generation and spread of ripples. Qualitatively similar ripples occurred at all levels of the LA and propagated in both directions: septally or temporally, with an average speed of 0.35m/sec. While ripples propagated smoothly in the septal 2/3rd of the hippocampal tissue, ripples in the ventral segment remained isolated. These findings suggest that the septal hippocampus can use ripples to combine the information before transferring integrated signals to downstream targets. However, because ripples occur at different times in the ventral and dorsal segments, they broadcast independent information to their non-overlapping cortical and subcortical targets.
Distributed Training and Optimization Of Neural Networks
Creators: name: Vlimant, Jean-Roch
name: Yin, Junqi
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Deep learning models are yielding increasingly better performances thanks to multiple factors. To be successful, model may have large number of parameters or complex architectures and be trained on large dataset. This leads to large requirements on computing resource and turn around time, even more so when hyper-parameter optimization is done (e.g search over model architectures). While this is a challenge that goes beyond particle physics, we review the various ways to do the necessary computations in parallel, and put it in the context of high energy physics.
description: 20 pages, 4 figures, 2 tables, Submitted for review. To appear in "Artificial Intelligence for Particle Physics", World Scientific Publishing
Alignment-dependent decay rate of an atomic dipole near an optical nanofiber
Creators: name: Solano, Pablo
name: Grover, Jeffrey A.
name: Xu, Yunlu
name: Barberis-Blostein, Pablo
name: Munday, Jeremy N.
name: Orozco, Luis A.
name: Phillips, William D.
name: Rolston, Steven L.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We study the modification of the atomic spontaneous emission rate, i.e. Purcell effect, of $^{87}$Rb in the vicinity of an optical nanofiber ($\sim$500 nm diameter). We observe enhancement and inhibition of the atomic decay rate depending on the alignment of the induced atomic dipole relative to the nanofiber. Finite-difference time-domain simulations are in quantitative agreement with the measurements when considering the atoms as simple oscillating linear dipoles. This is surprising since the multi-level nature of the atoms should produce a different radiation pattern, predicting smaller modification of the lifetime than the measured ones. This work is a step towards characterizing and controlling atomic properties near optical waveguides, fundamental tools for the development of quantum photonics.
Multi-sense embeddings through a word sense disambiguation process
Creators: name: Ruas, Terry
name: Grosky, William
name: Aizawa, Akiko
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: Natural Language Understanding has seen an increasing number of publications in the last few years, especially after robust word embeddings models became prominent, when they proved themselves able to capture and represent semantic relationships from massive amounts of data. Nevertheless, traditional models often fall short in intrinsic issues of linguistics, such as polysemy and homonymy. Any expert system that makes use of natural language in its core, can be affected by a weak semantic representation of text, resulting in inaccurate outcomes based on poor decisions. To mitigate such issues, we propose a novel approach called Most Suitable Sense Annotation (MSSA), that disambiguates and annotates each word by its specific sense, considering the semantic effects of its context. Our approach brings three main contributions to the semantic representation scenario: (i) an unsupervised technique that disambiguates and annotates words by their senses, (ii) a multi-sense embeddings model that can be extended to any traditional word embeddings algorithm, and (iii) a recurrent methodology that allows our models to be re-used and their representations refined. We test our approach on six different benchmarks for the word similarity task, showing that our approach can produce state-of-the-art results and outperforms several more complex state-of-the-art systems.
Comparing PyMorph and SDSS photometry. I. Background sky and model fitting effects
Creators: name: Fischer, J. -L.
name: Bernardi, M.
name: Meert, A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: A number of recent estimates of the total luminosities of galaxies in the SDSS are significantly larger than those reported by the SDSS pipeline. This is because of a combination of three effects: one is simply a matter of defining the scale out to which one integrates the fit when defining the total luminosity, and amounts on average to < 0.1 mags even for the most luminous galaxies. The other two are less trivial and tend to be larger; they are due to differences in how the background sky is estimated and what model is fit to the surface brightness profile. We show that PyMorph sky estimates are fainter than those of the SDSS DR7 or DR9 pipelines, but are in excellent agreement with the estimates of Blanton et al. (2011). Using the SDSS sky biases luminosities by more than a few tenths of a magnitude for objects with half-light radii > 7 arcseconds. In the SDSS main galaxy sample these are typically luminous galaxies, so they are not necessarily nearby. This bias becomes worse when allowing the model more freedom to fit the surface brightness profile. When PyMorph sky values are used, then two component Sersic-Exponential fits to E+S0s return more light than single component deVaucouleurs fits (up to ~0.2 mag), but less light than single Sersic fits (0.1 mag). Finally, we show that PyMorph fits of Meert et al. (2015) to DR7 data remain valid for DR9 images. Our findings show that, especially at large luminosities, these PyMorph estimates should be preferred to the SDSS pipeline values.
description: 12 pages, 17 figures, accepted for publication in MNRAS
Enriching students' conceptual understanding of confidence intervals: An interactive trivia-based classroom activity
Creators: name: Wang, Xiaofei
name: Reich, Nicholas G.
name: Horton, Nicholas J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Other Statistics (stat.OT)
subject: FOS: Computer and information sciences
subject: 62-01

description: Confidence intervals provide a way to determine plausible values for a population parameter. They are omnipresent in research articles involving statistical analyses. Appropriately, a key statistical literacy learning objective is the ability to interpret and understand confidence intervals in a wide range of settings. As instructors, we devote a considerable amount of time and effort to ensure that students master this topic in introductory courses and beyond. Yet, studies continue to find that confidence intervals are commonly misinterpreted and that even experts have trouble calibrating their individual confidence levels. In this article, we present a ten-minute trivia game-based activity that addresses these misconceptions by exposing students to confidence intervals from a personal perspective. We describe how the activity can be integrated into a statistics course as a one-time activity or with repetition at intervals throughout a course, discuss results of using the activity in class, and present possible extensions.
description: 18 pages; in press at the American Statistician
Enhanced word embeddings using multi-semantic representation through lexical chains
Creators: name: Ruas, Terry
name: Ferreira, Charles Henrique Porto
name: Grosky, William
name: de França, Fabrício Olivetti
name: Medeiros, Débora Maria Rossi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: The relationship between words in a sentence often tells us more about the underlying semantic content of a document than its actual words, individually. In this work, we propose two novel algorithms, called Flexible Lexical Chain II and Fixed Lexical Chain II. These algorithms combine the semantic relations derived from lexical chains, prior knowledge from lexical databases, and the robustness of the distributional hypothesis in word embeddings as building blocks forming a single system. In short, our approach has three main contributions: (i) a set of techniques that fully integrate word embeddings and lexical chains; (ii) a more robust semantic representation that considers the latent relation between words in a document; and (iii) lightweight word embeddings models that can be extended to any natural language task. We intend to assess the knowledge of pre-trained models to evaluate their robustness in the document classification task. The proposed techniques are tested against seven word embeddings algorithms using five different machine learning classifiers over six scenarios in the document classification task. Our results show the integration between lexical chains and word embeddings representations sustain state-of-the-art results, even against more complex systems.
Inter-regional synchronization in the hippocampal system by oscillations
Creators: name: Sullivan, David W.
Publisher: name: No Publisher Supplied
Year: 2013

description: This dissertation investigated how several different types of oscillation organize neural activity in the hippocampus and the entorhinal cortex. I used recordings performed by myself and others to explore the nature of the ripple, sharp wave, fast gamma, theta, and spindle oscillations, the manner in which these oscillations propagate through the hippocampal network, and how behavior affects the properties of these oscillations. The first study concerned two types of high frequency oscillation in CA1: fast gamma and ripples, their relationship to sharp waves, the nature of their emergence in CA3 and propagation to CA1, and their interaction with slow oscillations during sleep. I found that the ripple oscillation emerges de novo in CA1 rather than being transmitted wave-by-wave from CA3 to CA1. I also found that there is an inverted-U shaped relationship between the peak frequency of ripple oscillations and the amplitude of sharp waves. The second study extended the observations of the first study by taking the behavioral state of the animal into account. I found that the ripples that occur intermidst active behavior oscillate at a higher frequency than those that occur during sleep and quiescence, and that the relationship between sharp wave amplitude and ripple frequency differs depending on behavioral state. I also found that ripples that are detected during running are due to recording artifacts, whereas ripples occasionally occur during REM sleep. The third study examined the nature of sleep spindles in the hippocampus, and is an exploration (and ultimately, a rejection) of the hypothesis that the mechanisms of sleep spindles are the same. I found that many neurons prefer different oscillation phases of theta and spindles, suggesting that different sets of inputs drive neurons. I also found that principal cells are not rhythmically entrained by spindle oscillations; this and the lack of phase precession during spindles led to the conclusion that spindles should not be considered as a special case of theta.
Canonical density matrices from eigenstates of mixed systems
Creators: name: Kourehpaz, Mahdi
name: Donsa, Stefan
name: Lackner, Fabian
name: Burgdörfer, Joachim
name: Březinová, Iva
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: One key issue of the foundation of statistical mechanics is the emergence of equilibrium ensembles in isolated and closed quantum systems. Recently, it was predicted that in the thermodynamic ($N\rightarrow\infty$) limit of large quantum many-body systems canonical density matrices emerge for small subsystems from almost all pure states. This notion of canonical typicality is assumed to originate from the entanglement between subsystem and environment and the resulting intrinsic quantum complexity of the many-body state. For individual eigenstates it has been shown that local observables show thermal properties provided the eigenstate thermalization hypothesis holds, which requires the system to be quantum chaotic. In the present paper, we study the emergence of thermal states in the regime of a quantum analog of a mixed phase space. Specifically, we study the emergence of the canonical density matrix of an impurity upon reduction from isolated energy eigenstates of a large but finite quantum system the impurity is embedded in. Our system can be tuned by means of a single parameter from quantum integrability to quantum chaos and corresponds in between to a system with mixed quantum phase space. We show that the probability for finding a canonical density matrix when reducing the ensemble of energy eigenstates of the finite many-body system can be quantitatively controlled and tuned by the degree of quantum chaos present. For the transition from quantum integrability to quantum chaos we find a continuous and universal (i.e. size independent) relation between the fraction of canonical eigenstates and the degree of chaoticity as measured by the Brody parameter or the Shannon entropy.
description: 17 pages, 13 figures
Radiolysis of water confined in porous silica: A simulation study of the physicochemical yields
Creators: name: Ouerdane, H.
name: Gervais, B.
name: Zhou, H.
name: Beuve, M.
name: Renault, J. -Ph.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: We investigate the radiolysis of liquid water confined in a porous silica matrix by means of an event-by-event Monte Carlo simulation of electron penetration in this composite system. We focus on the physical and physicochemical effects that take place in the picosecond range, before the radicals start to diffuse and react. We determine the radiolytic yields of the primary species for a system made of cylindrical pores filled with water over a wide range of pore radii $R_{\rm C}$. We show that the relative position of the conduction band edge $V_0$ in both materials plays a major role in the radiolysis of composite systems. Due to its lower $V_0$ as compared to that of silica, water acts as a collector of low-energy electrons, which leads to a huge enhancement of the solvated electron yields for $R_{\rm C} \leq$ 100 nm. The confinement has also a marked effect on the spatial distribution of the radicals, which become isolated in a very large number of pores as $R_{\rm C}$ decreases.
El archivo de escritor como reivindicación: el Itinerario intelectual de Antonio Acevedo Escobedo (UNAM, 2020) de Dayna Díaz Uribe
Creators: name: Pérez Sánchez, Luis Felipe
Publisher: name: Universidad Autónoma de Queréataro
Year: 2024

description: Reseña del libro: 

El archivo de escritor como reivindicación: el Itinerario intelectual de Antonio Acevedo Escobedo (UNAM, 2020) de Dayna Díaz Uribe
Basal forebrain cholinergic system: studies on intrinsic physiology and connectivity
Creators: name: Ünal, Çağri Temuçin
Publisher: name: No Publisher Supplied
Year: 2013

description: The term basal forebrain (BF) refers to a collection of nuclei found in the ventromedial aspects of the mammalian forebrain. The cholinergic corticopetal neurons in these nuclei received particular attention due to the intricate involvement of acetylcholine in cardinal cognitive functions. These neurons are referred to as the basal forebrain cholinergic (BFc) neurons and constitute the BFc system. This thesis asks three questions regarding the BFc system. The first question (Aim 1) pertains to the electrophysiological properties of its constituent neurons. Second question (Aim 2) deals with their interactions. The final question (Aim 3) is aimed at answering how these neurons modulate cellular properties in target neurons, considering the regular-spiking (RS) basolateral amygdala (BLA) neurons as a model system. To answer these questions, patch-clamp recordings in acute brain slices obtained from transgenic mice were done. The cholinergic effects on BFc neurons themselves and RS-BLA neurons were studied via optogenetically stimulating BFc neurons. Aim 1 revealed that BFc neurons can be differentiated into two electrophysiologically identifiable subtypes: early and late firing neurons. Early firing neurons (70%) are more excitable, show prominent spike frequency adaptation and are more susceptible to depolarization blockade, a phenomenon characterized by complete silencing of the neuron following an initial discharge of action potentials. Late firing neurons (30%), albeit being less excitable, could maintain a tonic discharge at low frequencies. In Aim 2, the inhibitory nature of BFc interactions were revealed using different approaches of slice electrophysiology that include the application of cholinergic agonists/antagonists, paired whole-cell recordings, and optogenetic activation of a subset of BFc neurons while recording the postsynaptic responses in others. The mechanisms and potential functional implications of these inhibitory actions are discussed in detail later. Experiments in Aim 3 were concerned with the effects of endogeneously released acetylcholine on RS-BLA neurons. The results reveal that cholinergic action depends on the recent history of RS-BLA neurons: It is excitatory following high frequency prior spiking while muscarinic inhibition dominates during lower firing frequencies. These results might point out to a thresholding function of acetylcholine in vivo.
On the mean profiles of radio pulsars II: Reconstruction of complex pulsar light-curves and other new propagation effects
Creators: name: Hakobyan, Hayk
name: Beskin, Vasily
name: Philippov, Alexander
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Our previous paper outlined the general aspects of the theory of radio light curve and polarization formation for pulsars. We predicted the one-to-one correspondence between the tilt of the linear polarization position angle of the and the circular polarization. However, some of the radio pulsars indicate a clear deviation from that correlation. In this paper we apply the theory of the radio wave propagation in the pulsar magnetosphere for the analysis of individual effects leading to these deviations. We show that within our theory the circular polarization of a given mode can switch its sign, without the need to introduce a new radiation mode or other effects. Moreover, we show that the generation of different emission modes on different altitudes can explain pulsars, that presumably have the X-O-X light-curve pattern, different from what we predict. General properties of radio emission within our propagation theory are also discussed. In particular, we calculate the intensity patterns for different radiation altitudes and present light curves for different observer viewing angles. In this context we also study the light curves and polarization profiles for pulsars with interpulses. Further, we explain the characteristic width of the position angle curves by introducing the concept of a wide emitting region. Another important feature of radio polarization profiles is the shift of the position angle from the center, which in some cases demonstrates a weak dependence on the observation frequency. Here we demonstrate that propagation effects do not necessarily imply a significant frequency-dependent change of the position angle curve.
description: 16 pages, 20 figures, 3 tables, submitted for publishing in MNRAS
Analysis of Charge Order in the Kagome Metal $A$V$_3$Sb$_5$ ($A=$K,Rb,Cs)
Creators: name: Denner, M. Michael
name: Thomale, Ronny
name: Neupert, Titus
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: Motivated by the recent discovery of unconventional charge order, we develop a theory of electronically mediated charge density wave formation in the family of kagome metals $A$V$_3$Sb$_5$ ($A=$K,Rb,Cs). The intertwining of van Hove filling and sublattice interference suggests a three-fold charge density wave instability at T$_{\text{CDW}}$. From there, the charge order forming below T$_{\text{CDW}}$ can unfold into a variety of phases capable of exhibiting orbital currents and nematicity. We develop a Ginzburg Landau formalism to stake out the parameter space of kagome charge order. We find a nematic chiral charge order to be energetically preferred, which shows tentative agreement with experimental evidence.
description: 5 pages, 3 figures & Supplementary Material
Strongly Interacting Phases of Metallic Wires in Strong Magnetic Field
Creators: name: Bulmash, Daniel
name: Jian, Chao-Ming
name: Qi, Xiao-Liang
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate theoretically an interacting metallic wire with a strong magnetic field directed along its length and show that it is a new and highly tunable one-dimensional system. By considering a suitable change in spatial geometry, we map the problem in the zeroth Landau level with Landau level degeneracy $N$ to one-dimensional fermions with an $N$-component pseudospin degree of freedom and $SU(2)$-symmetric interactions. This mapping allows us to establish the phase diagram as a function of the interactions for small $N$ (and make conjectures for large $N$) using renormalization group and bosonization techniques. We find pseudospin-charge separation with a gapless $U(1)$ charge sector and several possible strong-coupling phases in the pseudospin sector. For odd $N$, we find a fluctuating pseudospin-singlet charge density wave phase and a fluctuating pseudospin-singlet superconducting phase which are topologically distinct. For even $N>2$, similar phases exist, although they are not topologically distinct, and an additional, novel pseudospin-gapless phase appears. We discuss experimental conditions for observing our proposals.
description: 19+6 pages, 5 figures
Terpene synthase gene amplicons from subseafloor sediment
Creators: name: Schmidt, Ruth L.
name: Hoshino, Tatsuhiko
name: Morono, Yuki
name: Tremblay, Julien
name: Ulanova, Dana
Publisher: name: Zenodo
Year: 2022

description: We sequenced putative terpene synthase (TS) gene fragments. These fragments were amplified using subseafloor sediment sample collected off Shimokita Peninsula, Japan, and primers targeting geosmin and 2-methylisoborneol synthases. Amplicons were sequenced using Illumina platform. This technical note describes details of raw read processing and OTU taxonomic annotation.
From banks to DeFi: the evolution of the lending market
Creators: name: Xu, Jiahua
name: Vadgama, Nikhil
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computers and Society (cs.CY)
subject: General Economics (econ.GN)
subject: FOS: Computer and information sciences
subject: FOS: Economics and business

description: The Internet of Value (IOV) with its distributed ledger technology (DLT) underpinning has created new forms of lending markets. As an integral part of the decentralised finance (DeFi) ecosystem, lending protocols are gaining tremendous traction, holding an aggregate liquidity supply of over $40 billion at the time of writing. In this paper, we enumerate the challenges of traditional money markets led by banks and lending platforms, and present advantageous characteristics of DeFi lending protocols that might help resolve deep-rooted issues in the conventional lending environment. With the examples of Maker, Compound and Aave, we describe in detail the mechanism of DeFi lending protocols. We discuss the persisting reliance of DeFi lending on the traditional financial system, and conclude with the outlook of the lending market in the IOV era.
Single-photon description of the lossless optical Y coupler
Creators: name: Schwarze, Christopher R.
name: Manni, Anthony D.
name: Simon, David S.
name: Sergienko, Alexander V.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Using symmetry considerations, we derive a unitary scattering matrix for a three-port optical Y-coupler or Y-branch. The result is shown to be unique up to external phase shifts. Unlike traditional passive linear-optical one-way splitters, coupling light into the conventional output ports of the Y-coupler results in strong coherent back-reflections, making the device a hybrid between feed-forward devices like the beam splitter, which do not reverse the direction of light, and a recently considered class of directionally unbiased multiport scatterers (with dimension greater than two) which do. While the device could immediately find use as a novel scattering vertex for the implementation of quantum walks, we also design a few simple but nonetheless useful optical systems that can be constructed by taking advantage of the symmetry of the scattering process. This includes an interference-free, resource-efficient implementation of the Grover four-port and a higher-dimensional Fabry-Perot interferometer with tunable finesse. Symmetry-breaking generalizations are also considered.
Sectionable Tournaments: Their topology and Coloring
Creators: name: Deniz, Zakir
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C20, 05E45, 57Q70, 05C15

description: We provide a detailed study of topological and combinatorial properties of sectionable tournaments. This class forms an inductively constructed family of tournaments grounded over simply disconnected tournaments, those tournaments whose fundamental groups of acyclic complexes are non-trivial. When $T$ is a sectionable tournament, we fully describe the cell-structure of its acyclic complex $Acy(T)$ by using the adapted machinery of discrete Morse theory for acyclic complexes of tournaments. In the combinatorial side, we demonstrate that the dimension of the complex $Acy(T)$ has a role to play. We prove that if $T$ is a $(2r+1)$-sectionable tournament and $d$ is the dimension of $Acy(T)$, then the (acyclic) chromatic number of $T$ satisfies $χ(T)\leq 2 \left( 2-1/(r+1) \right)^{\log(d+1)}-1$ where the logarithm has two as its base.
description: 21 pages
RG stability of integrable fishnet models
Creators: name: Mamroud, Ohad
name: Torrents, Genis
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We address the question of perturbative consistency in the scalar fishnet models presented by Caetano, Gurdogan and Kazakov\cite{Gurdogan:2015csr, Caetano:2016ydc}. We argue that their 3-dimensional $ϕ^{6}$ fishnet model becomes perturbatively stable under renormalization in the large $N$ limit, in contrast to what happens in their 4-dimensional $ϕ^{4}$ fishnet model, in which double trace terms are known to be generated by the RG flow. We point out that there is a direct way to modify this second theory that protects it from such corrections. Additionally, we observe that the 6-dimensional $ϕ^{3}$ Lagrangian that spans an hexagonal integrable scalar fishnet is consistent at the perturbative level as well. The nontriviality and simplicity of this last model is illustrated by computing the anomalous dimensions of its $\text{tr}ϕ_i ϕ_j$ operators to all perturbative orders.
description: 25 pages, 15 figures. V2: Added references, minor corrections
Axial crushing of circular thin-walled specimens made of CFRP using progressive failure model (MAT54) in LS-Dyna
Creators: Kumar, Yogesh
Rezasefat, Mohammad
Hogan, James D.
Publisher: name: University of Alberta Library
Year: 2023

This research focuses on calibrating the MAT54 (ENHANCEDCOMPOSITEDAMAGE) material card in LS-Dyna for simulating axial crushing of circular thin-walled specimens made of CFRP. An IM7/8552 composite specimen showing the layup sequence of [902/±452/02]2 was simulated in LS-Dyna using shell elements. Following a trial-and-error-based method, the physical and non-physical input material parameters of MAT54 were calibrated. The calibrated input parameters included material strengths, failure strains, softening factors, and damping coefficient. The results of this study showed the applicability of the use of the physical material inputs from material characterization tests (e.g., tensile, in-plane shear, and compression) while showing the necessity of more in-depth calibration processes for the non-physical material inputs (e.g., viscous damping coefficient, crashfront reduction algorithm, etc.). The initial model predicted the specific energy absorption with an error of −57.95 % and this was improved by the calibration process to an error equal to −1.49 % for the final model. Now validated, the model will be used in the future to simulate impact into composite vehicle armor.