cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Palynology of the Triassic–Jurassic transition of the Danish Basin (Denmark): a palynostratigraphic zonation of the Gassum–lower Fjerritslev formations
Creators: name: Lindström, Sofie
name: Pedersen, Gunver Krarup
name: Vosgerau, Henrik
name: Hovikoski, Jussi
name: Dybkjær, Karen
name: Nielsen, Lars Henrik
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: FOS: Biological sciences
subject: Astronomical and Space Sciences not elsewhere classified
subject: Biological Sciences not elsewhere classified
subject: Inorganic Chemistry
subject: FOS: Chemical sciences

description: The Upper Triassic–Lower Jurassic succession in the Danish Basin is penetrated by many deep wells that were drilled during former hydrocarbon exploration campaigns, but it is today targeted for geothermal energy and storage of CO2. The Stenlille salt dome on Sjælland sandstones of the Gassum Formation, sealed by the overlying Fjerritslev Formation mudstones, has been used for decades as a seasonal storage for natural gas. With its comprehensive dataset of seismics, geophysical well logs and conventional core data from 20 wells, the Stenlille succession serves as a model for other salt domes currently being evaluated as potential CO2 storage sites in the basin. Over the last decade the cored Triassic–Jurassic boundary succession has contributed to the understanding of environmental and palynological events during the end-Triassic mass extinction. Core, sidewall core and cutting samples from several of the closely situated Stenlille wells are here used to establish a high-resolution palynostratigraphic zonation scheme covering the entire Rhaetian to Sinemurian succession by integrating new analyses with previously published data. The palynological dataset has allowed the recognition of nine formally described spore-pollen zones, of which eight are new, while two previously described dinoflagellate cyst zones are subdivided into three informal subzones each. The palynological zonation is integrated with a sequence stratigraphic framework and will form the basis for the dating of future well sections in the Danish Basin and other basins and for correlation to outcrops. The large palynological dataset further shows that the vegetation around the Danish Basin was remarkably stable during the early to middle Rhaetian, but that events related to the emplacement of the Central Atlantic Magmatic Province accelerated ecosystem changes for c. 175 ky in the late Rhaetian and earliest Hettangian, including ∼25 ky of successional recovery before the terrestrial ecosystem had again stabilised.
Plant Growth Form Effects on North and South Carolina Species Abundance Distribution Patterns
Creators: name: Orndahl, Kathleen
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2014

description: The distribution of species abundance throughout a flora begs important questions about how communities are organized which can in turn lead to important discoveries about how communities are organized. Many studies have investigated the distribution of species abundance at a number of different scales, but none have made a clear distinction between the relative abundances of woody and herbaceous taxa within a flora. I investigated the species abundance distribution of the Carolina Vegeation Survey data for North and South Carolina, with a specific eye on the previously noted phenomenon of woody taxa (trees and lianas in particular) occurring predominantly at high abundances (proportions of plots) as compared to herbaceous taxa. Analysis of data showed that trees and lianas do indeed seem to represent a disproportionate number of the most abundant species. Furthermore, these woody taxa are able to tolerate and utilize a wider range of soil resources than herbaceous taxa. On a case-by-case basis, a larger range for a specific soil property did not necessarily correlate with higher proportion of plots occupied, but given the high abundance and habitat generalism of trees and lianas in the flora, the congregation of many wide ranges for a variety of soil properties likely does contribute to higher proportion of plots occupied. More potential causes need to be investigated, however, to fully explain this pattern.
The Fragility of the Terrestrial Planets During a Giant Planet Instability
Creators: name: Kaib, Nathan A.
name: Chambers, John E.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Many features of the outer solar system are replicated in numerical simulations if the giant planets undergo an orbital instability that ejects one or more ice giants. During this instability, Jupiter and Saturn's orbits diverge, crossing their 2:1 mean motion resonance (MMR), and this resonance-crossing can excite the terrestrial planet orbits. Using a large ensemble of simulations of this giant planet instability, we directly model the evolution of the terrestrial planet orbits during this process, paying special attention to systems that reproduce the basic features of the outer planets. In systems that retain four giant planets and finish with Jupiter and Saturn beyond their 2:1 MMR, we find at least an 85% probability that at least one terrestrial planet is lost. Moreover, systems that manage to retain all four terrestrial planets often finish with terrestrial planet eccentricities and inclinations larger than the observed ones. There is less than a ~5% chance that the terrestrial planet orbits will have a level of excitation comparable to the observed orbits. If we factor in the probability that the outer planetary orbits are well-replicated, we find a probability of 1% or less that the orbital architectures of the inner and outer planets are simultaneously reproduced in the same system. These small probabilities raise the prospect that the giant planet instability occurred before the terrestrial planets had formed. This scenario implies that the giant planet instability is not the source of the Late Heavy Bombardment and that terrestrial planet formation finished with the giant planets in their modern configuration.
description: Accepted to MNRAS, 10 pages, 5 figures, 2 tables
LiDiTE: a Full-Fledged and Featherweight Digital Twin Framework
Creators: name: Russo, Enrico
name: Costa, Gabriele
name: Longo, Giacomo
name: Armando, Alessandro
name: Merlo, Alessio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: The rising of the Cyber-Physical System (CPS) and the Industry 4.0 paradigms demands the design and the implementation of Digital Twin Frameworks (DTFs) that may support the quick build of reliable Digital Twins (DTs) for experimental and testing purposes. Most of the current DTF proposals allow generating DTs at a good pace but affect generality, scalability, portability, and completeness. As a consequence, current DTF are mostly domain-specific and hardly span several application domains (e.g., from simple IoT deployments to the modeling of complex critical infrastructures). Furthermore, the generated DTs often requires a high amount of computational resource to run. In this paper, we present LiDiTE, a novel DTF that overcomes the previous limitations by, on the one hand, supporting the building of general-purpose DTs at a fine-grained level, but, on the other hand, with a reduced resource footprint w.r.t. the current state of the art. We show the characteristics of the LiDiTE by building the DT of a complex and real critical infrastructure (i.e., the Smart Poligeneration Microgrid of the Savona Campus) and evaluating its resource consumption. The source code of LiDiTE, as well as the experimental dataset, is publicly available.
A derivation of the standard model particles from the Dirac Lagrangian on internal spacetime
Creators: name: Beil, Charlie
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Physics (physics.gen-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: 'Internal spacetime' is a modification of general relativity that was recently introduced as an approximate spacetime geometric model of quantum nonlocality. In an internal spacetime, time is stationary along the worldlines of fundamental (dust) particles. Consequently, the dimensions of tangent spaces at different points of spacetime vary, and spin wavefunction collapse is modeled by the projection from one tangent space to another. In this article we develop spinors on an internal spacetime, and construct a new Dirac-like Lagrangian $\mathcal{L} = \barψ(i \slashed \partial - \hatω) ψ$ whose equations of motion describe their couplings and interactions. Furthermore, we show that hidden within $\mathcal{L}$ is the entire standard model: $\mathcal{L}$ contains precisely three generations of quarks and leptons, the electroweak gauge bosons, the Higgs boson, and one new massive spin-$2$ boson; gluons are considered in a companion article. Specifically, we are able to derive the correct spin, electric charge, and color charge of each standard model particle, as well as predict the existence of a new boson.
description: 25 pages. Final version. (This paper is a companion to arXiv:1908.09631 and partly replaces its earlier versions; two tables and one figure here also appear in the 'Preliminaries' section of its final version.)
Numerical Simulations of the Ram Pressure-Driven Rayleigh-Taylor Instability
Creators: name: Hilderbran, Maggie
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2019

description: Star formation in the Galactic disk is fueled by continuous accretion of gas from the Galactic halo. This infalling gas is usually identified in the form of high-velocity clouds (HVCs), so named because their velocities do not match a standard Galactic rotation pattern. As they pass through the halo, HVCs are disrupted by a series of fluid instabilities. The Rayleigh-Taylor instability (RTI), driven by ram pressure, occurs at the interface between the cold, dense cloud and the hot, diffuse halo. I perform a systematic investigation of the RTI under conditions relevant to HVCs in the halo, exploring how the instability contributes to the breakup of these clouds. I use the grid-based fluid dynamics code Athena (Stone et al. 2008) to solve the equations of ideal magnetohydrodynamics, simulating the instability at the halo-cloud interface. Step-by-step addition of radiative processes and magnetic fields provides an understanding of their effects on the evolution of the RTI. Cooling causes rapid fragmentation of the interface and dampens the instability, in line with Vietri et al. (1997). The addition of a uniform magnetic field suppresses the instability in two dimensions but not in three dimensions, consistent with Stone & Gardiner (2007). In contrast, tangled magnetic fields, which may be a more realistic model, produce results more like the hydrodynamical case. Because the plane-parallel geometry I assume does not take into account mass flow around (and away from) the interface, the instability growth found in my models is likely an upper limit compared to more realistic situations.
Palynotaxonomy of Calea sect. Meyeria (Asteraceae: Neurolaeneae)
Creators: name: Cartaxo-Pinto, Simone
name: Vieira, Ilgner Fernando Tavares
name: Nascimento, Jeane Marinho
name: Bueno, Vinicius R.
name: Heiden, Gustavo
name: Mendonça, Cláudia Barbieri Ferreira
name: Gonçalves-Esteves, Vania
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Cell Biology
subject: Molecular Biology
subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: Environmental Sciences not elsewhere classified
subject: Ecology
subject: Biological Sciences not elsewhere classified
subject: Marine Biology
subject: Plant Biology

description: Calea comprises 157 species that occur in the Neotropics. The genus is organized into eight subgenera and 18 sections. Calea sect. Meyeria consists of eight species occurring exclusively in south-central Brazil. In this study, pollen grains from these eight species were sampled from herborized flower buds in pre-anthesis. Pollen samples were acetolyzed, measured, and photographed under a light microscope. Unacetolyzed pollen grains were examined under a scanning electron microscope. The results were used to characterize pollen morphology and construct a palynotaxonomic key for Calea sect. Meyeria. The analyzed pollen grains were monads, isopolar, usually medium-sized, oblate spheroidal, tricolporate, with lalongate endoaperture, the sexine echinate and thicker than the nexine, and six spines in the apocolpium region. The eight species have very similar pollen grains, but some characters are informative for this section, namely pollen size, polar area, sexine ornamentation, and endoaperture characteristics. Despite the similarity of the pollen grains, palynological analysis was able to contribute to the delimitation of Calea species, providing new information for species distinction within Calea sect. Meyeria.
Non-Hermitian Squeezed Polarons
Creators: name: Qin, Fang
name: Shen, Ruizhe
name: Lee, Ching Hua
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Recent experimental breakthroughs in non-Hermitian ultracold atomic lattices have dangled tantalizing prospects in realizing exotic, hitherto unreported, many-body non-Hermitian quantum phenomena. In this work, we discover and propose an experimental platform for a radically different non-Hermitian phenomenon dubbed polaron squeezing. It is marked by a dipole-like accumulation of fermions arising from an interacting impurity in a background of non-Hermitian reciprocity-breaking hoppings. We computed their spatial density and found that, unlike Hermitian polarons which are symmetrically localized around impurities, non-Hermitian squeezed polarons localize asymmetrically in the direction opposite to conventional non-Hermitian pumping and non-perturbatively modify the entire spectrum, despite having a manifestly local profile. We investigated their time evolution and found that, saliently, they appear almost universally in the long-time steady state, unlike Hermitian polarons which only exist in the ground state. In our numerics, we also found that, unlike well-known topological or skin localized states, squeezed polarons exist in the bulk, independently of boundary conditions. Our findings could inspire the realization of many-body states in ultracold atomic setups, where a squeezed polaron can be readily detected and characterized by imaging the spatial fermionic density.
description: 29 pages, 13 figures, update references, published version
The Best Thresholds for Rapid Identification of Episodic and Chronic Homeless Shelter Use
Creators: name: Messier, Geoffrey Guy
name: Tutty, Leslie
name: John, Caleb
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: This paper explores how to best identify clients for housing services based on their homeless shelter access patterns. We focus on counting the number of shelter stays and episodes of shelter use for a client within a time window. Thresholds are then applied to these values to determine if that individual is a good candidate for housing support. Using new housing referral impact metrics, we explore a range of threshold and time window values to determine which combination both maximizes impact and identifies good candidates for housing as soon as possible. New insights are also provided regarding the characteristics of the "under-the-radar" client group who are typically not identified for housing support.
The energy resolution function of a tunnel junction
Creators: name: Ast, Christian R.
name: Jäck, Berthold
name: Senkpiel, Jacob
name: Eltschka, Matthias
name: Etzkorn, Markus
name: Ankerhold, Joachim
name: Kern, Klaus
Publisher: name: arXiv
Year: 2015
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The tunnel junction between tip and sample in a scanning tunneling microscope is an ideal platform to access the local density of states in the sample through the differential conductance. We show that the energy resolution that can be obtained is principally limited by the electromagnetic interaction of the tunneling electrons with the surrounding environmental impedance as well as the capacitative noise of the junction. The parameter tuning the sensitivity to the environmental impedance is the capacitance of the tunnel junction. The higher the junction capacitance, the less sensitive the tunnel junction to the environment resulting in better energy resolution. Modeling this effect within P(E)-theory, the P(E)-function describes the probability for a tunneling electron to exchange energy with the environment and can be regarded as the resolution function of the tunnel junction. We experimentally demonstrate this effect in a scanning tunneling microscope with a superconducting aluminum tip and a superconducting aluminum sample at a base temperature of 15mK, where it is most pronounced.
description: 7 pages, 5 figures
Cellular Network Capacity and Coverage Enhancement with MDT Data and Deep Reinforcement Learning
Creators: name: Skocaj, Marco
name: Amorosa, Lorenzo Mario
name: Ghinamo, Giorgio
name: Muratore, Giuliano
name: Micheli, Davide
name: Zabini, Flavio
name: Verdone, Roberto
Publisher: name: arXiv
Year: 2022
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Recent years witnessed a remarkable increase in the availability of data and computing resources in communication networks. This contributed to the rise of data-driven over model-driven algorithms for network automation. This paper investigates a Minimization of Drive Tests (MDT)-driven Deep Reinforcement Learning (DRL) algorithm to optimize coverage and capacity by tuning antennas tilts on a cluster of cells from TIM's cellular network. We jointly utilize MDT data, electromagnetic simulations, and network Key Performance indicators (KPIs) to define a simulated network environment for the training of a Deep Q-Network (DQN) agent. Some tweaks have been introduced to the classical DQN formulation to improve the agent's sample efficiency, stability, and performance. In particular, a custom exploration policy is designed to introduce soft constraints at training time. Results show that the proposed algorithm outperforms baseline approaches like DQN and best-fist search in terms of long-term reward and sample efficiency. Our results indicate that MDT-driven approaches constitute a valuable tool for autonomous coverage and capacity optimization of mobile radio networks.
description: 15 pages, 17 figures
Chaotic Weak Chimeras and their Persistence in Coupled Populations of Phase Oscillators
Creators: name: Bick, Christian
name: Ashwin, Peter
Publisher: name: arXiv
Year: 2015
Subjects: subject: Dynamical Systems (math.DS)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: Chaotic Dynamics (nlin.CD)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Nontrivial collective behavior may emerge from the interactive dynamics of many oscillatory units. Chimera states are chaotic patterns of spatially localized coherent and incoherent oscillations. The recently-introduced notion of a weak chimera gives a rigorously testable characterization of chimera states for finite-dimensional phase oscillator networks. In this paper we give some persistence results for dynamically invariant sets under perturbations and apply them to coupled populations of phase oscillators with generalized coupling. In contrast to the weak chimeras with nonpositive maximal Lyapunov exponents constructed so far, we show that weak chimeras that are chaotic can exist in the limit of vanishing coupling between coupled populations of phase oscillators. We present numerical evidence that positive Lyapunov exponents can persist for a positive measure set of this inter-population coupling strength.
Exact invariant measures: How the strength of measure settles the intensity of chaos
Creators: name: Venegeroles, Roberto
Publisher: name: arXiv
Year: 2015
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The aim of this paper is to show how extracting dynamical behavior and ergodic properties from deterministic chaos with the assistance of exact invariant measures. On the one hand, we provide an approach to deal with the inverse problem of finding nonlinear interval maps from a given invariant measure. Then, we show how to identify ergodic properties by means of transitions along the phase space via exact measures. On the other hand, we discuss quantitatively how infinite measures imply maps having subexponential Lyapunov instability (weakly chaotic), as opposed to finite measure ergodic maps, that are fully chaotic. In addition, we provide general solutions of maps for which infinite invariant measures are exactly known throughout the interval (a demand from this field). Finally, we give a simple proof that infinite measure implies universal Mittag-Leffler statistics of observables, rather than narrow distributions typically observed in finite measure ergodic maps.
description: 8 pages, 2 figures (revised version)
Coupled-Cluster Theory Revisited. Part I: Discretization
Creators: name: Csirik, Mihály A.
name: Laestadius, Andre
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: Mathematical Physics (math-ph)
subject: Chemical Physics (physics.chem-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: In a series of two articles, we propose a comprehensive mathematical framework for Coupled-Cluster-type methods. These methods aim at accurately solving the many-body Schrodinger equation. In this first part, we rigorously describe the discretization schemes involved in Coupled-Cluster methods using graph-based concepts. This allows us to discuss different methods in a unified and more transparent manner, including multireference methods. Moreover, we derive the single-reference and the Jeziorski-Monkhorst multireference Coupled-Cluster equations in a unified and rigorous manner.
description: Published in ESAIM: M2AN, Volume 57, Number 2, March-April 2023, Pages 645 -670
Investigation of Photochemical Hydrogen Evolution from Ruthenium Hydrides
Creators: name: Wong, Teddy
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2018

description: Visible light-triggered hydrogen evolution from (C6R6)Ru(bpy)(H)+ (R=H, Me, bpy = 2,2ʹ-bipyridine) systems is reported. A range of arene Ru hydrides was isolated and their photochemical properties analyzed in water and acetonitrile. The electrochemical properties of these complexes were then studied in water. Photolysis studies indicate a similar mechanistic pathway as the Ir system. Understanding the chemical mechanism and electrochemical properties will motivate future design of molecular photoswitchable hydride catalysts.
Robust Multi-Agent Bandits Over Undirected Graphs
Creators: name: Vial, Daniel
name: Shakkottai, Sanjay
name: Srikant, R.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Multiagent Systems (cs.MA)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: We consider a multi-agent multi-armed bandit setting in which $n$ honest agents collaborate over a network to minimize regret but $m$ malicious agents can disrupt learning arbitrarily. Assuming the network is the complete graph, existing algorithms incur $O( (m + K/n) \log (T) / Δ)$ regret in this setting, where $K$ is the number of arms and $Δ$ is the arm gap. For $m \ll K$, this improves over the single-agent baseline regret of $O(K\log(T)/Δ)$. In this work, we show the situation is murkier beyond the case of a complete graph. In particular, we prove that if the state-of-the-art algorithm is used on the undirected line graph, honest agents can suffer (nearly) linear regret until time is doubly exponential in $K$ and $n$. In light of this negative result, we propose a new algorithm for which the $i$-th agent has regret $O( ( d_{\text{mal}}(i) + K/n) \log(T)/Δ)$ on any connected and undirected graph, where $d_{\text{mal}}(i)$ is the number of $i$'s neighbors who are malicious. Thus, we generalize existing regret bounds beyond the complete graph (where $d_{\text{mal}}(i) = m$), and show the effect of malicious agents is entirely local (in the sense that only the $d_{\text{mal}}(i)$ malicious agents directly connected to $i$ affect its long-term regret).
Early Science with the Large Millimeter Telescope: COOL BUDHIES I - a pilot study of molecular and atomic gas at z~0.2
Creators: name: Cybulski, Ryan
name: Yun, Min S.
name: Erickson, Neal
name: De la Luz, Victor
name: Narayanan, Gopal
name: Montaña, Alfredo
name: Sánchez-Argülles, David
name: Zavala, Jorge A.
name: Zeballos, Milagros
name: Chung, Aeree
name: Fernández, Ximena
name: van Gorkom, Jacqueline
name: Haines, Chris P.
name: Jaffé, Yara L.
name: Montero-Castaño, María
name: Poggianti, Bianca M.
name: Verheijen, Marc A. W.
name: Yoon, Hyein
name: Harrington, Kevin
name: Hughes, David H.
name: Morrison, Glenn E.
name: Schloerb, F. Peter
name: Velazquez, Miguel
Publisher: name: arXiv
Year: 2015
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: An understanding of the mass build-up in galaxies over time necessitates tracing the evolution of cold gas (molecular and atomic) in galaxies. To that end, we have conducted a pilot study called CO Observations with the LMT of the Blind Ultra-Deep H I Environment Survey (COOL BUDHIES). We have observed 23 galaxies in and around the two clusters Abell 2192 (z = 0.188) and Abell 963 (z = 0.206), where 12 are cluster members and 11 are slightly in the foreground or background, using about 28 total hours on the Redshift Search Receiver (RSR) on the Large Millimeter Telescope (LMT) to measure the $^{12}$CO J = 1 --> 0 emission line and obtain molecular gas masses. These new observations provide a unique opportunity to probe both the molecular and atomic components of galaxies as a function of environment beyond the local Universe. For our sample of 23 galaxies, nine have reliable detections (S/N$\geq$3.6) of the $^{12}$CO line, and another six have marginal detections (2.0 < S/N < 3.6). For the remaining eight targets we can place upper limits on molecular gas masses roughly between $10^9$ and $10^{10} M_\odot$. Comparing our results to other studies of molecular gas, we find that our sample is significantly more abundant in molecular gas overall, when compared to the stellar and the atomic gas component, and our median molecular gas fraction lies about $1σ$ above the upper limits of proposed redshift evolution in earlier studies. We discuss possible reasons for this discrepancy, with the most likely conclusion being target selection and Eddington bias.
description: MNRAS, submitted
Entanglement Domain Walls in Monitored Quantum Circuits and the Directed Polymer in a Random Environment
Creators: name: Li, Yaodong
name: Vijay, Sagar
name: Fisher, Matthew P. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Monitored quantum dynamics reveal quantum state trajectories which exhibit a rich phenomenology of entanglement structures, including a transition from a weakly-monitored volume law entangled phase to a strongly-monitored area law phase. For one-dimensional hybrid circuits with both random unitary dynamics and interspersed measurements, we combine analytic mappings to an effective statistical mechanics model with extensive numerical simulations on hybrid Clifford circuits to demonstrate that the universal entanglement properties of the volume law phase can be quantitatively described by a fluctuating entanglement domain wall that is equivalent to a "directed polymer in a random environment" (DPRE). This relationship improves upon a qualitative "mean-field" statistical mechanics of the volume-law-entangled phase [1, 2]. For the Clifford circuit in various geometries, we obtain agreement between the subleading entanglement entropies and error correcting properties of the volume-law phase (which quantify its stability to projective measurements) with predictions of the DPRE. We further demonstrate that depolarizing noise in the hybrid dynamics near the final circuit time can drive a continuous phase transition to a non-error correcting volume law phase that is not immune to the disentangling action of projective measurements. We observe this transition in hybrid Clifford dynamics, and obtain quantitative agreement with critical exponents for a "pinning" phase transition of the DPRE in the presence of an attractive interface.
description: 22 pages, 18 figures
A knot without a nonorientable essential spanning surface
Creators: name: Dunfield, Nathan M.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 57M

description: This note gives the first example of a hyperbolic knot in the 3-sphere that lacks a nonorientable essential spanning surface; this disproves the Strong Neuwirth Conjecture formulated by Ozawa and Rubinstein. Moreover, this knot has no even strict boundary slopes, disproving the Even Boundary Slope Conjecture of the same authors. The proof is a rigorous calculation using Thurston's spun-normal surfaces in the spirit of Haken's original normal surface algorithms.
description: 6 pages, 1 figure. V2: Minor edits, to appear in Illinois J. Math
Predicting Chronic Homelessness: The Importance of Comparing Algorithms using Client Histories
Creators: name: Messier, Geoffrey G.
name: John, Caleb
name: Malik, Ayush
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: This paper investigates how to best compare algorithms for predicting chronic homelessness for the purpose of identifying good candidates for housing programs. Predictive methods can rapidly refer potentially chronic shelter users to housing but also sometimes incorrectly identify individuals who will not become chronic (false positives). We use shelter access histories to demonstrate that these false positives are often still good candidates for housing. Using this approach, we compare a simple threshold method for predicting chronic homelessness to the more complex logistic regression and neural network algorithms. While traditional binary classification performance metrics show that the machine learning algorithms perform better than the threshold technique, an examination of the shelter access histories of the cohorts identified by the three algorithms show that they select groups with very similar characteristics. This has important implications for resource constrained not-for-profit organizations since the threshold technique can be implemented using much simpler information technology infrastructure than the machine learning algorithms.
Photometry and dynamics of the minor mergers AM\,1228-260 and AM\,2058-381
Creators: name: Hernandez-Jimenez, J. A.
name: Pastoriza, M. G.
name: Bonatto, C.
name: Rodrigues, I.
name: Krabbe, A. C.
name: Winge, Cláudia
Publisher: name: arXiv
Year: 2015
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We investigate interaction effects on the dynamics and morphology of the galaxy pairs AM\,2058-381 and AM\,1228-260. This work is based on $r'$ images and long-slit spectra obtained with the Gemini Multi-Object Spectrograph at the Gemini South Telescope. The luminosity ratio between the main (AM\,2058A) and secondary (AM\,2058B) components of the first pair is a factor of $\sim$ 5, while for the other pair, the main (AM\,1228A) component is 20 times more luminous than the secondary (AM\,1228B). The four galaxies have pseudo-bulges, with a Sérsic index $n<2$. Their observed radial velocities profiles (RVPs) present several irregularities. The receding side of the RVP of AM\,2058A is displaced with respect to the velocity field model, while there is a strong evidence that AM\,2058B is a tumbling body, rotating along its major axis. The RVPs for AM\,1228A indicate a misalignment between the kinematic and photometric major axes. The RVP for AM\,1228B is quite perturbed, very likely due to the interaction with AM\,1228A. NFW halo parameters for AM\,2058A are similar to those of the Milky Way and M\,31. The halo mass of AM\,1228A is roughly 10\% that of AM\,2058A. The mass-to-light (M/L) of AM\,2058 agrees with the mean value derived for late-type spirals, while the low M/L for AM\,1228A may be due to the intense star formation ongoing in this galaxy.
description: 20 pages, 10 figures, accepted for publication in MNRAS
Creative "Hobby" as Manual Physical Engagement and Human Flourishing
Creators: name: Lin, Jason
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2019

description: Much research has been conducted on artisans around the world who pursue crafting careers as a means to finance themselves and their families. Global artisan research tends to focus on community, innovation, and marketability. Western artisan research tends to focus on sustainability and fair-trade. However, there is a lack of research on craft that is pursued for pleasure and as an escape from the work world. These hobbyist artisans are usually overlooked because there seemed to be no key themes to be drawn out of crafts that do not involve economics. However, an ethnography on the Chapel Hill Woodturners' Club, a community of mostly retired hobbyist woodturners, gave evidence that there is much to be drawn out by studying them. This includes transfer of knowledge from instructors to newcomers, innovation to create new and unique products, and a hidden economy that becomes apparent in a hobbyist craft community. From this research, questions regarding both artisans and the term "hobby" are raised. Are there communities that contain both hobbyist artisans and financially driven artisans and, if so, how do the social dynamics change? Since hobbies are usually looked down upon as less important as work, should there be a shift in the meaning of the word itself? This thesis also serves as a call-to-action for more research on similar hobbyist artisanal communities in a possibly new branch of cultural anthropology.
Integrating Nijenhuis Structures
Creators: name: Pugliese, Fabrizio
name: Sparano, Giovanni
name: Vitagliano, Luca
Publisher: name: arXiv
Year: 2022
Subjects: subject: Differential Geometry (math.DG)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 22A22, 53D17, 58A50

description: A Nijenhuis operator on a manifold $M$ is a $(1,1)$ tensor $\mathcal N$ whose Nijenhuis-torsion vanishes. A Nijenhuis operator $\mathcal N$ on $M$ determines a Lie algebroid structure $(TM)_{\mathcal N}$ on the tangent bundle $TM$. In this sense a Nijenhuis operator can be seen as an infinitesimal object. In this paper, we identify its "global counterpart". Namely, we show that when the Lie algebroid $(TM)_{\mathcal N}$ is integrable, then it integrates to a Lie groupoid equipped with appropriate additional structure responsible for $\mathcal N$, and viceversa, the Lie algebroid of a Lie groupoid equipped with such additional structure is of the type $(TM)_{\mathcal N}$ for some Nijenhuis operator $\mathcal N$. We illustrate our integration result in various examples.
description: 22 pages, comments welcome
Exploring uncertainties in dark energy constraints using current observational data with Planck 2015 distance priors
Creators: name: Wang, Yun
name: Dai, Mi
Publisher: name: arXiv
Year: 2015
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present the distance priors that we have derived from the 2015 Planck data, and use these in combination with the latest observational data from Type Ia Supernovae (SNe Ia) and galaxy clustering, to explore the systematic uncertainties in dark energy constraints. We use the Joint Lightcurve Analysis (JLA) set of 740 SNe Ia, galaxy clustering measurements of H(z)s and D_A(z)/s (where s is the sound horizon at the drag epoch) from the Sloan Digital Sky Survey (SDSS) at z=0.35 and z=0.57 (BOSS DR12). We find that the combined dark energy constraints are insensitive to the assumptions made in the galaxy clustering measurements (whether they are for BAO only or marginalized over RSD), which indicates that as the analysis of galaxy clustering data becomes more accurate and robust, the systematic uncertainties are reduced. On the other hand, we find that flux-averaging SNe Ia at z>= 0.5 significantly tightens the dark energy constraints, and excludes a flat universe with a cosmological constant at 68% confidence level, assuming a dark energy equation of state linear in the cosmic scale factor. Flux-averaging has the most significant effect when we allow dark energy density function X(z) to be a free functions given by the cubic spline of its value at z=0, 1/3, 2/3, 1; the measured X(z) deviates from a cosmological constant at more than 95% confidence level for 0.4 < z < 0.7. Since flux-averaging reduces the bias in the SN distance measurements, this may be an indication that we have arrived in the era when the SN distance measurements are limited by systematic uncertainties.
description: 8 pages, 11 figures. Significantly expanded to include different dark energy parametrizations, and BOSS DR12 data. PRD, in press. arXiv admin note: text overlap with arXiv:1304.4514, arXiv:1109.3172; text overlap with arXiv:1310.6109 by other authors
Supplemental Material for manuscript titled "Vitamin D binding protein and post-surgical outcomes and tissue injury markers after hip fracture: a prospective study".
Creators: name: Meng, Lingqiong
name: Wang, Xiangbing
name: L Carson, Jeffrey
name: Schlussel, Yvette
name: Shapses, Sue
Publisher: name: figshare
Year: 2023
Subjects: classificationCode: 320208
subject: Endocrinology
classificationCode: 320226
subject: Surgery

description: Overview of supplementary tablesTable S1. Correlation between pre-operative biochemical markers in patients with hip fracture Table S2. Correlation between pre-operative inflammatory cytokines with biochemical markers in subset of patients with hip fractureOverview of supplementary figureFigure S1. Odds ratio of outcomes after hip fracture surgery assessed by pre-operative (A) Total 25OHD, (B) Free 25OHD, and (C) IL-6 tertiles in whole patient population for mobility and mortality
Rapidly Encoding Generalizable Dynamics in a Euclidean Symmetric Neural Network
Creators: name: Li, Qiaofeng
name: Wang, Tianyi
name: Roychowdhury, Vwani
name: Jawed, M. Khalid
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Slinky, a helical elastic rod, is a seemingly simple structure with unusual mechanical behavior; for example, it can walk down a flight of stairs under its own weight. Taking Slinky as a test-case, we propose a physics-informed deep learning approach for building reduced-order models of physical systems. The approach introduces a Euclidean symmetric neural network (ESNN) architecture that is trained under the neural ordinary differential equation framework to learn the 2D latent dynamics from the motion trajectory of a reduced-order representation of the 3D Slinky. The ESNN implements a physics-guided architecture that simultaneously preserves energy invariance and force equivariance under Euclidean transformations of the input, including translation, rotation, and reflection. The embedded Euclidean symmetry provides physics-guided interpretability and generalizability, while preserving the full expressive power of the neural network. We demonstrate that the ESNN approach is able to accelerate simulation by one to two orders of magnitude compared to traditional numerical methods and achieve a superior generalization performance while classic neural networks fail to learn the Slinky dynamics, i.e., the ESNN, trained on a single demonstration case, predicts the motions accurately for unseen cases of different Slinky configurations and boundary conditions. Further investigation into the ESNN reveals that it explicitly learns the nonlinear coupling between stretching and bending of the Slinky.
description: Supplementary video available at https://youtu.be/mHCFa8U9Xpw
Pharmacokinetics of antitubercular drugs in patients hospitalized with HIV-associated tuberculosis: a population modeling analysis
Creators: name: Abdelgawad, Noha
name: Chirehwa, Maxwell
name: Schutz, Charlotte
name: Barr, David
name: Ward, Amy
name: Janssen, Saskia
name: Burton, Rosie
name: Wilkinson, Robert J
name: Shey, Muki
name: Wiesner, Lubbe
name: McIlleron, Helen
name: Maartens, Gary
name: Meintjes, Graeme
name: Denti, Paolo
Publisher: name: The Francis Crick Institute
Year: 2024
Subjects: classificationCode: Infectious Disease
subject: Infectious Disease
classificationCode: Immunology
subject: Immunology
subject: FOS: Clinical medicine
classificationCode: Human Biology & Physiology
subject: Human Biology & Physiology
classificationCode: Model organisms
subject: Model organisms

description: Background Early mortality among hospitalized HIV-associated tuberculosis (TB/HIV) patients is high despite treatment. The pharmacokinetics of rifampicin, isoniazid, and pyrazinamide were investigated in hospitalized TB/HIV patients and a cohort of outpatients with TB (with or without HIV) to determine whether drug exposures differed between groups. Methods Standard first-line TB treatment was given daily as per national guidelines, which consisted of oral 4-drug fixed-dose combination tablets containing 150 mg rifampicin, 75 mg isoniazid, 400 mg pyrazinamide, and 275 mg ethambutol. Plasma samples were drawn on the 3rd day of treatment over eight hours post-dose. Rifampicin, isoniazid, and pyrazinamide in plasma were quantified and NONMEM® was used to analyze the data. Results Data from 60 hospitalized patients (11 of whom died within 12 weeks of starting treatment) and 48 outpatients were available. Median (range) weight and age were 56 (35 - 88) kg, and 37 (19 - 77) years, respectively. Bioavailability and clearance of the three drugs were similar between TB/HIV hospitalized and TB outpatients. However, rifampicin’s absorption was slower in hospitalized patients than in outpatients; mean absorption time was 49.9% and 154% more in hospitalized survivors and hospitalized deaths, respectively, than in outpatients. Higher levels of conjugated bilirubin correlated with lower rifampicin clearance. Isoniazid’s clearance estimates were 25.5 L/h for fast metabolizers and 9.76 L/h for slow metabolizers. Pyrazinamide’s clearance was more variable among hospitalized patients. The variability in clearance among patients was 1.70 and 3.56 times more for hospitalized survivors and hospitalized deaths, respectively, than outpatients. Conclusions We showed that the pharmacokinetics of first-line TB drugs are not substantially different between hospitalized TB/HIV patients and TB (with or without HIV) outpatients. Hospitalized patients do not seem to be underexposed compared to their outpatient counterparts, as well as hospitalized patients who survived vs who died within 12 weeks of hospitalization.
Feature Flow Regularization: Improving Structured Sparsity in Deep Neural Networks
Creators: name: Wu, Yue
name: Lan, Yuan
name: Zhang, Luchan
name: Xiang, Yang
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Pruning is a model compression method that removes redundant parameters in deep neural networks (DNNs) while maintaining accuracy. Most available filter pruning methods require complex treatments such as iterative pruning, features statistics/ranking, or additional optimization designs in the training process. In this paper, we propose a simple and effective regularization strategy from a new perspective of evolution of features, which we call feature flow regularization (FFR), for improving structured sparsity and filter pruning in DNNs. Specifically, FFR imposes controls on the gradient and curvature of feature flow along the neural network, which implicitly increases the sparsity of the parameters. The principle behind FFR is that coherent and smooth evolution of features will lead to an efficient network that avoids redundant parameters. The high structured sparsity obtained from FFR enables us to prune filters effectively. Experiments with VGGNets, ResNets on CIFAR-10/100, and Tiny ImageNet datasets demonstrate that FFR can significantly improve both unstructured and structured sparsity. Our pruning results in terms of reduction of parameters and FLOPs are comparable to or even better than those of state-of-the-art pruning methods.
Recognition of affine-equivalent polyhedra by their natural developments
Creators: name: Alexandrov, Victor
Publisher: name: arXiv
Year: 2021
Subjects: subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 52C25, 52B10, 51M25

description: The classical Cauchy rigidity theorem for convex polytopes reads that if two convex polytopes have isometric developments then they are congruent. In other words, we can decide whether two polyhedra are isometric or not by using their developments only. In this article, we study a similar problem about whether it is possible, using only the developments of two convex polyhedra of Euclidean 3-space, to understand that these polyhedra are (or are not) affine-equivalent.
description: 21 pages, 4 figures; this v4 is an English translation of v3 which is in Russian
Computer modeling of $t\bar{t}h(H)$ Higgs boson production with MSSM model
Creators: name: Obikhod, Tetiana
name: Petrenko, Ievgenii
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We studied the properties of the MSSM Higgs bosons, h and H through the decay into b-quarks in associated production with a top-quark pair. There was used the tree-level Higgs sector described by two parameters M$_A$ and tan$β$ and found their optimal values according to experimental data of ATLAS detector. Using the restricted parameter space we calculated cross sections of associated $t\bar{t}h(H)$ production at 13 and 14 TeV, the corresponding kinematical cuts, mass distributions and Branching Ratios of h and H decays into $b\bar{b}$ quark pair.
description: 6 pages, 7 figures