cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Metaheuristic Algorithms for Convolution Neural Network
Creators: name: Rere, L. M. Rasdi
name: Fanany, Mohamad Ivan
name: Arymurthy, Aniati Murni
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences
subject: I.2.10
subject: 68Txx

description: A typical modern optimization technique is usually either heuristic or metaheuristic. This technique has managed to solve some optimization problems in the research area of science, engineering, and industry. However, implementation strategy of metaheuristic for accuracy improvement on convolution neural networks (CNN), a famous deep learning method, is still rarely investigated. Deep learning relates to a type of machine learning technique, where its aim is to move closer to the goal of artificial intelligence of creating a machine that could successfully perform any intellectual tasks that can be carried out by a human. In this paper, we propose the implementation strategy of three popular metaheuristic approaches, that is, simulated annealing, differential evolution, and harmony search, to optimize CNN. The performances of these metaheuristic methods in optimizing CNN on classifying MNIST and CIFAR dataset were evaluated and compared. Furthermore, the proposed methods are also compared with the original CNN. Although the proposed methods show an increase in the computation time, their accuracy has also been improved (up to 7.14 percent).
description: Article ID 1537325, 13 pages. Received 29 January 2016; Revised 15 April 2016; Accepted 10 May 2016. Academic Editor: Martin Hagan. in Hindawi Publishing. Computational Intelligence and Neuroscience Volume 2016 (2016)
Large shift current via in-gap and charge-neutral exciton excitations in BN nanotubes and single BN layer
Creators: name: Huang, Yi-Shiuan
name: Chan, Yang-Hao
name: Guo, Guang-Yu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Applied Physics (physics.app-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We perform {\it ab initio} many-body calculations to investigate the exciton shift current in small diameter zigzag BN nanotubes and also single BN sheet, using the GW plus Bethe-Salpeter equation (GW-BSE) method with the newly developed efficient algorithms. Our GW-BSE calculations reveal a giant in-gap peak in the shift current spectrum in all the studied BN systems due to the excitation of the A exciton. The peak value of the excitonic shift current is more than three times larger than that of the quasiparticle shift current, and is attributed to the gigantic enhancement of the optical dipole matrix element by the A exciton resonance. The effective exciton shift current conductivity is nearly ten times larger than the largest shift conductivity observed in ferroelectric semiconductors. Importantly, the direction of the shift current in the BN nanotubes is found to be independent of the tube chirality ($n,0$) (or diameter), contrary to the simple rule of $ sgn(J_\text{shift})=\text{mod}(n,3)$ predicted by previous model Hamiltonian studies. Finally, our {\it ab initio} calculations also show that the exciton excitation energies decrease significantly with the decreasing diameter due to the curvature-induced orbital rehybridization in small diameter zigzag BN nanotubes.
description: 12 pages, 8 figures and 2 tables
Evaluating the Impact of Social Determinants on Health Prediction in the Intensive Care Unit
Creators: name: Yang, Ming Ying
name: Kwak, Gloria Hyunjung
name: Pollard, Tom
name: Celi, Leo Anthony
name: Ghassemi, Marzyeh
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: Social determinants of health (SDOH) -- the conditions in which people live, grow, and age -- play a crucial role in a person's health and well-being. There is a large, compelling body of evidence in population health studies showing that a wide range of SDOH is strongly correlated with health outcomes. Yet, a majority of the risk prediction models based on electronic health records (EHR) do not incorporate a comprehensive set of SDOH features as they are often noisy or simply unavailable. Our work links a publicly available EHR database, MIMIC-IV, to well-documented SDOH features. We investigate the impact of such features on common EHR prediction tasks across different patient populations. We find that community-level SDOH features do not improve model performance for a general patient population, but can improve data-limited model fairness for specific subpopulations. We also demonstrate that SDOH features are vital for conducting thorough audits of algorithmic biases beyond protective attributes. We hope the new integrated EHR-SDOH database will enable studies on the relationship between community health and individual outcomes and provide new benchmarks to study algorithmic biases beyond race, gender, and age.
The Ursa Major cluster redefined as a `supergroup'
Creators: name: Wolfinger, K.
name: Kilborn, V. A.
name: Ryan-Weber, E. V.
name: Koribalski, B. S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We identify gravitationally bound structures in the Ursa Major region using positions, velocities and photometry from the Sloan Digital Sky Survey (SDSS DR7) and the Third Reference Catalogue of Bright Galaxies (RC3). A friends-of-friends algorithm is extensively tested on mock galaxy lightcones and then implemented on the real data to determine galaxy groups whose members are likely to be physically and dynamically associated with one another. We find several galaxy groups within the region that are likely bound to one another and in the process of merging. We classify 6 galaxy groups as the Ursa Major `supergroup', which are likely to merge and form a poor cluster with a mass of ~8x10^13 Msun. Furthermore, the Ursa Major supergroup as a whole is likely bound to the Virgo cluster, which will eventually form an even larger system in the context of hierarchical structure formation. [abridged]
description: 40 pages, 28 figures. PASA accepted 22 July 2016
Qualification of piezo-electric actuators for the MADMAX booster system at cryogenic temperatures and high magnetic fields
Creators: name: Garutti, E.
name: Janssen, H.
name: Kreikemeyer-Lorenzo, D.
name: Krieger, C.
name: Lindner, A.
name: Majorovits, B.
name: Schaffran, J.
name: van Bree, B.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: We report on the qualification of a piezo-based linear stage for the manipulation of positions of dielectric discs in the booster of the MADMAX axion dark matter search experiment. A first demonstrator of the piezo drives, specifically developed for MADMAX, was tested at room temperature as well as at cryogenic temperatures down to 4.5 K and inside strong magnetic fields up to 5.3 T. These qualification measurements prove that the piezo-based linear stage is suited for MADMAX and fulfills the requirements.
description: 13 pages, 9 figures, 2 tables
Towards Measuring the Ground State Hyperfine Splitting of Antihydrogen -- A Progress Report
Creators: name: Sauerzopf, C.
name: Capon, A.
name: Diermaier, M.
name: Dupré, P.
name: Higashi, Y.
name: Kaga, C.
name: Kolbinger, B.
name: Leali, M.
name: Lehner, S.
name: Rizzini, E. Lodi
name: Malbrunot, C.
name: Mascagna, V.
name: Massiczek, O.
name: Murtagh, D. J.
name: Nagata, Y.
name: Radics, B.
name: Simon, M. C.
name: Suzuki, K.
name: Tajima, M.
name: Ulmer, S.
name: Vamosi, S.
name: van Gorp, S.
name: Zmeskal, J.
name: Breuker, H.
name: Higaki, H.
name: Kanai, Y.
name: Kuroda, N.
name: Matsuda, Y.
name: Venturelli, L.
name: Widmann, E.
name: Yamazaki, Y.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: We report the successful commissioning and testing of a dedicated field-ioniser chamber for measuring principal quantum number distributions in antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new chamber is combined with a beam normalisation detector that consists of plastic scintillators and a retractable passivated implanted planar silicon (PIPS) detector.
description: 5 pages, 2 figures, 6th International Symposium on Symmetries in Subatomic Physics (SSP2015)
Euler--Chern Correspondence via Topological Superconductivity
Creators: name: Yang, Fan
name: Li, Xingyu
name: Li, Chengshu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The Fermi sea topology is characterized by the Euler characteristics $χ_F$. In this paper, we examine how $χ_F$ of the metallic state is inhereted by the topological invariant of the superconducting state. We establish a correspondence between the Euler characteristic and the Chern number $C$ of $p$-wave topological superconductors without time-reversal symmetry in two dimensions. By rewriting the pairing potential $Δ_{\bf k}=Δ_1-iΔ_2$ as a vector field ${\bf u}=(Δ_1,Δ_2)$, we found that $χ_F=C$ when ${\bf u}$ and fermion velocity ${\bf v}$ can be smoothly deformed to be parallel or antiparallel on each Fermi surface. We also discuss a similar correspondence between Euler characteristic and 3D winding number of time-reversal-invariant $p$-wave topological superconductors in three dimensions.
description: 6 pages, 3 figure
VLTI/AMBER spectro-interferometry of the late-type supergiants V766 Cen (=HR 5171 A), sigma Oph, BM Sco, and HD 206859
Creators: name: Wittkowski, M.
name: Arroyo-Torres, B.
name: Marcaide, J. M.
name: Abellan, F. J.
name: Chiavassa, A.
name: Guirado, J. C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We add four warmer late-type supergiants to our previous spectro-interferometric studies of red giants and supergiants. V766 Cen (=HR 5171 A) is found to be a high-luminosity log(L/L_sun)=5.8+-0.4 source of Teff 4290+-760 K and radius 1490+-540 Rsun located close to both the Hayashi and Eddington limits; this source is consistent with a 40 Msun evolutionary track without rotation and current mass 27-36 Msun. It exhibits NaI in emission arising from a shell of radius 1.5 Rphot and a photocenter displacement of about 0.1 Rphot. V766 Cen shows strong extended molecular (CO) layers and a dusty circumstellar background component. This suggest an optically thick pseudo-photosphere at about 1.5 Rphot at the onset of the wind. V766 Cen is a red supergiant located close to the Hayashi limit instead of a yellow hypergiant already evolving back toward warmer Teff as previously discussed. The stars sigma Oph, BM Sco, and HD 206859 are found to have lower luminosities of about log(L/Lsun)=3.4-3.5 and Teff of 3900-5300 K, corresponding to 5-9 Msun tracks. They do not show extended molecular layers as observed for higher luminosity red supergiants of our sample. BM Sco shows an unusually strong contribution by an over-resolved circumstellar dust component. These stars are more likely high-mass red giants instead of red supergiants. This leaves us with an unsampled locus in the HR diagram corresponding to luminosities log(L/Lsun)~3.8-4.8 or masses 10-13 Msun, possibly corresponding to the mass region where stars explode as type II-P supernovae during the RSG stage. Our previously found relation of increasing strength of extended molecular layers with increasing luminosities is now confirmed to extend to double our previous luminosities and up to the Eddington limit. This might further point to steadily increasing radiative winds with increasing luminosity. [Abridged]
description: 16 pages, 14 figures, accepted for publication in Astronomy and Astrophysics (A&A)
Orcovita Ng & Tomascik 1994
Creators: name: Stasolla, Gianluca
name: Innocenti, Gianna
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Varunidae
Orcovita

description: Orcovita Ng & Tomascik, 1994
Paratype – female, (15.8 × 12.2 mm) (ZRC 1996.112), Philippine, Coron Island, Raft Cave, Station 85-86, coll. T. M. Iliffe; 28 March 1985.
 Description. Carapace (Figs. 3A, 4A) subrectangular, distinctly broader than long (width/length ratio ca. 1.4), dorsal surface finely punctate; cervical grooves indistinct; gastric grooves deep with rounded concavity each laterally (<1 mm); epigastric cristae poorly defined, postorbital cristae absent; anterolateral margin lined with small and feeble granules; not clearly distinct from posterolateral margin in the left side of the carapace; external orbital angle broad, with one broad, epibranchial tooth (Fig. 4C), separated from external orbital angle by narrow V-shaped cleft; posterolateral margin concave converging towards the almost straight posterior carapace margin; supraorbital margin clearly granulated, gently sinuous, parallel to sub-parallel with frontal margin; frontal margin sinuous; infraorbital margin feebly granulated, incomplete, not congruent with anterolateral margin; distinct Diagnosis. (Modified from Ng & Tomascik, 1994) Carapace subrectangular, distinctly broader than long (width ca. 1.4 times length); dorsal surface relatively smooth; regions poorly defined; epigastric cristae low; postorbital cristae not discernible. External orbital angle very broad, with one low epibranchial tooth; frontal median triangle present, formed by 3 granular ridges. Third maxilliped with very broad, stout exopod, as wide or slightly wider than ischium; anteroexternal angle of merus strongly auriculiform. Chelipeds relatively long, pulvinus with setose base sometimes present at base of fingers of both male chelae, tip of fingers occasionally have short, dense setae. Ambulatory legs subcylindrical in cross-section, articles long and slender. Telson of male short, ca. 1.4 times length of segment 6. G1 relatively short, stout, tip truncate from lateral view.
description: Published as part of Stasolla, Gianluca & Innocenti, Gianna, 2014, A new species of cavernicolous crab from Coron Island, Palawan, the Philippines (Decapoda: Brachyura: Varunidae), pp. 591-599 in Raffles Bulletin Of Zoology 62 on page 592, DOI: 10.5281/zenodo.13609085
More Than Peer Production: Fanfiction Communities as Sites of Distributed Mentoring
Creators: name: Evans, Sarah
name: Davis, Katie
name: Evans, Abigail
name: Campbell, Julie Ann
name: Randall, David P.
name: Yin, Kodlee
name: Aragon, Cecilia
Publisher: name: arXiv
Year: 2016
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: Computers and Society (cs.CY)
subject: Social and Information Networks (cs.SI)
subject: FOS: Computer and information sciences
subject: H.5.3

description: From Harry Potter to American Horror Story, fanfiction is extremely popular among young people. Sites such as Fanfiction.net host millions of stories, with thousands more posted each day. Enthusiasts are sharing their writing and reading stories written by others. Exactly how does a generation known more for videogame expertise than long-form writing become so engaged in reading and writing in these communities? Via a nine-month ethnographic investigation of fanfiction communities that included participant observation, interviews, a thematic analysis of 4,500 reader reviews and an in-depth case study of a discussion group, we found that members of fanfiction communities spontaneously mentor each other in open forums, and that this mentoring builds upon previous interactions in a way that is distinct from traditional forms of mentoring and made possible by the affordances of networked publics. This work extends and develops the theory of distributed mentoring. Our findings illustrate how distributed mentoring supports fanfiction authors as they work to develop their writing skills. We believe distributed mentoring holds potential for supporting learning in a variety of formal and informal learning environments.
Structure and composition tunable superconductivity, band topology and elastic response of hard binary niobium nitrides Nb$_2$N, Nb$_4$N$_3$ and Nb$_4$N$_5$
Creators: name: Babu, K. Ramesh
name: Guo, Guang-Yu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We perform a systematic \textit{ab initio} density functional study of the superconductivity, electronic and phononic band structures, electron-phonon coupling and elastic constants of all four possible structures of niobium nitride $β$-Nb$_2$N as well as Nb-rich $γ$-Nb$_4$N$_3$ and N-rich $β^\prime$-Nb$_4$N$_5$. First of all, we find that all four structures of $β$-Nb$_2$N are superconductors with superconducting transition temperatures ($T_c$) ranging from 0.6 K to 6.1 K, depending on the structure. This explains why previous experiments reported contradicting $T_c$ values for $β$-Nb$_2$N. Furthermore, both $γ$-Nb$_4$N$_3$ and $β^\prime$-Nb$_4$N$_5$ are predicted to be superconductors with rather high $T_c$ of 8.5 K and 15.3 K, respectively. Second, the calculated elastic constants and phonon dispersion relations show that all the considered niobium nitride structures are mechanically and dynamically stable. Moreover, the calculated elastic moduli demonstrate that all the niobium nitrides are hard materials with bulk moduli and hardness being comparable to or larger than the well-known hard sapphire. Third, the calculated band structures reveal that the nitrides possess both type I and type II Dirac nodal points and are thus topological metals. Finally, the calculated electron-phonon coupling strength, superconductivity and mechanical property of the niobium nitrides are discussed in terms of their underlying electronic structures and also Debye temperatures. The present \textit{ab initio} study thus indicates that $β$-Nb$_2$N, $γ$-Nb$_4$N$_3$ and $β^\prime$-Nb$_4$N$_5$ are hard superconductors with nontrivial band topology and are promising materials for exploring exotic phenomena due to the interplay of hardness, superconductivity and nontrivial band topology.
description: 12 pages, 4 tables and 6 figures
Reimagining Gender and Sex: The Construction and Consumption of the Omegaverse
Creators: name: Ming, Yan
Publisher: name: University of Chicago
Year: 2022
Subjects: subject: Omegaverse
subject: Gender and Sex
subject: ABO

description: What is the relationship between gender and sex? What does a male body mean in the gender system? This thesis examines the popularity of the Omegaverse, an alternative gender system, and tries to explain why the Omegaverse has become a popular sub-genre in BL(Boy Love) stories, which involves the idealized romantic relationships between two cis male characters. The Omegaverse has provided an alternative universe in which biological sex markers, male and female genitals, are no longer the determining factor for sex. In other words, female and male identities no longer determine individuals’ social status yet popular stories involving the Omegaverse often incorporate two male characters. This thesis adopts content analysis on four of the most popular works on the Omegaverse and conversations happening on social media platforms surrounding the concept of the Omegaverse as well as interviews with the readers of these works. Through investigating the role male bodies play in the Omegaverse fictions, this thesis argues that male bodies serve as a symbol for success even when they are not functioning as a biological determining marker.
The Vattelian Law of Nations: A Legal Normativity in the Regional Context
Creators: name: Wang, Liang Chung
Publisher: name: University of Chicago
Year: 2022
Subjects: subject: Contextualism
subject: Legal Normativity
subject: Jus Naturae et Gentium
subject: The Double Law
subject: Universalism

description: This thesis investigates the normative character of Emer de Vattel’s jus gentium system as he constructs it in the treatise Le Droit des gens. Specifically, it confronts several interpretive and methodological issues generated by historian Ian Hunter’s contextualist reading of the subject text, who contends that Vattel committed to European affairs alone (or Eurocentric) in delineating the treatise’s normative scope. By analyzing the central set of concepts in Vattel’s work—the necessary and voluntary laws of nations—the thesis argues against Hunter. I suggest that Vattel’s theoretical design conveys his extra-European aspiration for the legal system’s applicable scope. Furthermore, through re-evaluating Hunter’s contextualist approach, I demonstrate that a universalistic interpretation of Vattel’s argument accurately captures the correspondence between his theoretical enterprise and contextual background. In short, this thesis contends that a contextualist reading of Vattel’s jus gentium indicates its normative character as universal.
Quantum Interference in Graphene Nanoconstrictions
Creators: name: Gehring, Pascal
name: Sadeghi, Hatef
name: Sangtarash, Sara
name: Lau, Chit Siong
name: Liu, Junjie
name: Ardavan, Arzhang
name: Warner, Jamie H.
name: Lambert, Colin J.
name: Briggs, G. Andrew. D.
name: Mol, Jan A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report quantum interference effects in the electrical conductance of chemical vapor deposited graphene nanoconstrictions fabricated using feedback controlled electroburning. The observed multimode Fabry-Perot interferences can be attributed to reflections at potential steps inside the channel. Sharp antiresonance features with a Fano line shape are observed. Theoretical modeling reveals that these Fano resonances are due to localized states inside the constriction, which couple to the delocalized states that also give rise to the Fabry-Perot interference patterns. This study provides new insight into the interplay between two fundamental forms of quantum interference in graphene nanoconstrictions.
Data-driven modeling and parameter estimation of Nonlinear systems
Creators: name: Kumar, Kaushal
Publisher: name: arXiv
Year: 2023
Subjects: subject: Systems and Control (eess.SY)
subject: Optimization and Control (math.OC)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Mathematics

description: Nonlinear systems play a significant role in numerous scientific and engineering disciplines, and comprehending their behavior is crucial for the development of effective control and prediction strategies. This paper introduces a novel data-driven approach for accurately modeling and estimating parameters of nonlinear systems utilizing trust region optimization. The proposed method is applied to three well-known systems: the Van der Pol oscillator, the Damped oscillator, and the Lorenz system, which find broad applications in engineering, physics, and biology. The results demonstrate the efficacy of the approach in accurately identifying the parameters of these nonlinear systems, enabling a reliable characterization of their behavior. Particularly in chaotic systems like the Lorenz system, capturing the dynamics on the attractor proves to be crucial. Overall, this article presents a robust data-driven approach for parameter estimation in nonlinear dynamical systems, holding promising potential for real-world applications.
description: 20 pages, 6 figures
Systems-level approach to uncovering diffusive states and their transitions from single particle trajectories
Creators: name: Koo, Peter K.
name: Mochrie, Simon G. J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: The stochastic motions of a diffusing particle contain information concerning the particle's interactions with binding partners and with its local environment. However, accurate determination of the underlying diffusive properties, beyond normal diffusion, has remained challenging when analyzing particle trajectories on an individual basis. Here, we introduce the maximum likelihood estimator (MLE) for confined diffusion and fractional Brownian motion. We demonstrate that this MLE yields improved estimation over traditional mean square displacement analyses. We also introduce a model selection scheme (that we call mleBIC) that classifies individual trajectories to a given diffusion mode. We demonstrate the statistical limitations of classification via mleBIC using simulated data. To overcome these limitations, we introduce a new version of perturbation expectation-maximization (pEMv2), which simultaneously analyzes a collection of particle trajectories to uncover the system of interactions which give rise to unique normal and/or non-normal diffusive states within the population. We test and evaluate the performance of pEMv2 on various sets of simulated particle trajectories, which transition among several modes of normal and non-normal diffusion, highlighting the key considerations for employing this analysis methodology.
Global Ambient Fine Particulate Matter Air Pollution and Human Health: Advanced Machine Learning Methodologies for Exposure and Health Risk Assessments
Creators: name: Yu, Wenhua
Publisher: name: Monash University
Year: 2024
Subjects: classificationCode: 461199
subject: Machine learning not elsewhere classified
classificationCode: 420203
subject: Environmental epidemiology
classificationCode: 420699
subject: Public health not elsewhere classified
classificationCode: 401101
subject: Air pollution modelling and control

description: Outdoor air pollution is a major health risk, but its global health impact from short-term exposure hasn’t been fully measured. This thesis develops an advanced machine learning framework to create detailed daily maps of air pollution from 2000 to 2019 and calculate the number of deaths due to short-term exposure. It provides the first global review of daily air pollution and its associated death toll at global, regional, national, and city levels over the past two decades.
X-ray: Discovering DRAM Internal Structure and Error Characteristics by Issuing Memory Commands
Creators: name: Nam, Hwayong
name: Baek, Seungmin
name: Wi, Minbok
name: Kim, Michael Jaemin
name: Park, Jaehyun
name: Song, Chihun
name: Kim, Nam Sung
name: Ahn, Jung Ho
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cryptography and Security (cs.CR)
subject: Hardware Architecture (cs.AR)
subject: FOS: Computer and information sciences

description: The demand for accurate information about the internal structure and characteristics of dynamic random-access memory (DRAM) has been on the rise. Recent studies have explored the structure and characteristics of DRAM to improve processing in memory, enhance reliability, and mitigate a vulnerability known as rowhammer. However, DRAM manufacturers only disclose limited information through official documents, making it difficult to find specific information about actual DRAM devices. This paper presents reliable findings on the internal structure and characteristics of DRAM using activate-induced bitflips (AIBs), retention time test, and row-copy operation. While previous studies have attempted to understand the internal behaviors of DRAM devices, they have only shown results without identifying the causes or have analyzed DRAM modules rather than individual chips. We first uncover the size, structure, and operation of DRAM subarrays and verify our findings on the characteristics of DRAM. Then, we correct misunderstood information related to AIBs and demonstrate experimental results supporting the cause of rowhammer. We expect that the information we uncover about the structure, behavior, and characteristics of DRAM will help future DRAM research.
description: 4 pages, 7 figures, accepted at IEEE Computer Architecture Letters
Holonomy groups of Lorentzian manifolds
Creators: name: Galaev, Anton S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Differential Geometry (math.DG)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: In this paper, a survey of the recent results about the classification of the connected holonomy groups of the Lorentzian manifolds is given. A simplification of the construction of the Lorentzian metrics with all possible connected holonomy groups is obtained. As the applications, the Einstein equation, Lorentzian manifolds with parallel and recurrent spinor fields, conformally flat Walker metrics and the classification of 2-symmetric Lorentzian manifolds are considered.
description: 49 pages; this is a survey on Lorentzian holonomy groups and their applications
Loss of hyperbolicity and tachyons in generalized Proca theories
Creators: name: Ünlütürk, Kıvanç İ.
name: Coates, Andrew
name: Ramazanoğlu, Fethi M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Various groups recently demonstrated that the time evolution of simplest self-interacting vector fields, those with self-interaction potentials, can break down after a finite duration in what is called loss of hyperbolicity. We establish that this is not an isolated issue, and other generalizations of the Proca theory suffer from the same problem. Specifically, we show that vector field theories with derivative self-interactions have a similar pathology. For this, we derive the effective metric that governs the dynamics, and show that it can change signature during time evolution. We also show that, generalized Proca theories may suffer from tachyonic instabilities as well, which lead to another form of unphysical behavior.
description: 10 pages, 4 figures; added a reference
Polarizability Plays a Decisive Role in Modulating Association Between Molecular Cations and Anions
Creators: name: Herman, Chase E.
name: Parambathu, Arjun Valiya
name: Asthagiri, D. N.
name: Lenhoff, Abraham M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Electrostatic interactions involving proteins depend not just on the ionic charges involved but also on their chemical identities. Here we examine the origins of incompletely understood differences in the strength of association of different pairs of monovalent molecular ions that are relevant to protein-protein and protein-ligand interactions. Cationic analogues of the basic amino acid side chains are simulated along with oxyanionic analogues of cation-exchange (CEX) ligands and acidic amino acids. Experimentally observed association trends with respect to the cations, but not anions, are captured by a non-polarizable model. A polarizable model proves decisive in capturing experimentally-suggested trends with respect to both cations and anions. Crucially, relative to a non-polarizable model, polarizability changes the free energy surface for ion-pair association, altering configurational sampling itself. An effective continuum correction to account for electronic polarizability can also capture the experimentally-suggested trends, but at the expense of fidelity to the underlying free energy surface.
Cosmological history in York time: inflation and perturbations
Creators: name: Roser, Philipp
name: Valentini, Antony
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The constant mean extrinsic curvature on a spacelike slice may constitute a physically preferred time coordinate, `York time'. One line of enquiry to probe this idea is to understand processes in our cosmological history in terms of York time. Following a review of the theoretical motivations, we focus on slow-roll inflation and the freezing and Hubble re-entry of cosmological perturbations. We show how the mathematical account of these processes is distinct from the conventional account in terms of standard cosmological or conformal time. We also consider the cosmological York-timeline more broadly and contrast it with the conventional cosmological timeline.
description: 10 pages, 1 figure
Unsharpness of generalized measurement and its effects in entropic uncertainty relations
Creators: name: Baek, Kyunghyun
name: Son, Wonmin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Under the scenario of generalized measurements, it can be questioned how much of quantum uncertainty can be attributed to measuring device, independent of the uncertainty in the measured system. On the course to answer the question, we suggest a new class of entropic uncertainty relation that differentiates quantum uncertainty from device imperfection due to the unsharpness of measurement. In order to quantify the unsharpness, we {suggest} and analyze the quantity that characterizes the uncertainty in the measuring device, based on Shannon entropy. Using the quantity, we obtain a new lower bound of entropic uncertainty with unsharpness and it has been shown that the relation can also be obtained under the scenario that sharp observables are affected by the white noise and amplitude damping.
description: 12 pages, 5 figures
Phase formation in hole- and electron-doped rare-earth nickelate single crystals
Creators: name: Puphal, P.
name: Sundaramurthy, V.
name: Zimmermann, V.
name: Küster, K.
name: Starke, U.
name: Isobe, M.
name: Keimer, B.
name: Hepting, M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The recent discovery of superconductivity in hole-doped infinite-layer nickelates has triggered a great interest in the synthesis of novel nickelate phases, which have primarily been examined in thin film samples. Here, we report the high-pressure optical floating zone (OFZ) growth of various perovskite and perovskite-derived rare-earth nickelate single-crystals, and investigate the effects of hole-, electron-, and self-doping. For hole-doping with Ca and Sr, we observe phase separations during the growth process when a substitution level of 8% is exceeded. A similar trend emerges for electron-doping with Ce and Zr. Employing lower doping levels allows us to grow sizeable crystals in the perovskite phase, which exhibit significantly different electronic and magnetic properties than the undoped parent compounds, such as a decreased resistivity and a suppressed magnetic response. Our insights into the doping-dependent phase formation and the resulting properties of the synthesized crystals reveal limitations and opportunities for the exploration and manipulation of electronic states in rare-earth nickelates.
The millimeter IRAM-30m line survey toward IK Tau
Creators: name: Prieto, L. Velilla
name: Contreras, C. Sánchez
name: Cernicharo, J.
name: Agúndez, M.
name: Quintana-Lacaci, G.
name: Bujarrabal, V.
name: Alcolea, J.
name: Balança, C.
name: Herpin, F.
name: Menten, K. M.
name: Wyrowski, F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We carried out a millimeter wavelength line survey between 79 and 356 GHz with the IRAM-30m telescope to investigate the physical and chemical properties of the molecular envelope of the oxygen-rich AGB star IK Tau. We analysed the molecular lines detected using the population diagram technique to derive rotational temperatures and column densities. Additionally, we conducted a radiative transfer analysis of the SO$_2$ lines detected. For the first time in this source we detected rotational lines in the ground vibrational state of HCO$^+$, NS, NO, and H$_2$CO, as well as several isotopologues of molecules previously identified. We also detected several rotational lines in vibrationally excited states of SiS and SiO isotopologues, and rotational lines of H$_2$O ($ν_{\mathrm{2}}$=2). We have also increased the number of rotational lines detected of molecules that were previously identified, enabling a detailed study of the molecular abundances and excitation temperatures. IK Tau displays a rich chemistry for an oxygen-rich circumstellar envelope. We highlight the detection of NS and H$_2$CO with fractional abundances of f(NS)$\sim$10$^{-8}$ and f(H$_2$CO)$\sim$[10$^{-7}$--10$^{-8}$]. Most of the molecules display rotational temperatures between 15 and 40 K. NaCl and SiS isotopologues display rotational temperatures higher than the average (~65 K). In the case of SO$_2$ a warm component with $T_{\mathrm{rot}}$$\sim$290 K is also detected. This SO$_2$ warm component is probably arising from the inner regions of the envelope (at $\sim$8$R_{*}$) where SO$_2$ has a fractional abundance of f(SO$_2$)$\sim$10$^{-6}$. This result should be considered for future investigation of the main formation channels of this, and other, parent species in the inner winds of O-rich AGB stars, which at present are not well reproduced by current chemistry models.
description: 47 pages, 26 figures. Accepted for Astronomy and Astrophysics
$Λ$ hypernuclear potentials beyond linear density dependence
Creators: name: Friedman, E.
name: Gal, A.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: In a recent paper [PLB 837 (2023) 137669] we showed that all measured ($1s_Λ$, $1p_Λ$) pairs of $Λ$ binding energies in $Λ$-hypernuclei across the periodic table, $12\leq A \leq 208$, can be obtained from a $Λ$-nucleus optical potential with only two adjustable $ΛN$ and $ΛNN$ parameters, associated with leading linear and quadratic terms in the nuclear density, derived by fitting $^{16}_{~Λ}$N binding energies. Here we extend the previous analysis by performing least-squares fits to the full set of data points. Consequences of suppressing $ΛNN$ interactions between `core' nucleons and `excess' neutrons are studied and related predictions are made for ($1s_Λ$, $1p_Λ$) binding energies in $^{40,48}_{~~~~Λ}$K, obtainable from upcoming $^{40,48}$Ca($e,e'K^+$) JLab experiments. We find $Λ$-nucleus partial potential depths of $D^{(2)}_Λ= -38.6\pm 0.8$~MeV ($ΛN$) and $D^{(3)}_Λ= 11.3\pm 1.4$~MeV ($ΛNN$), with a total depth $D_Λ= -27.3\pm 0.6$~MeV at nuclear-matter density $ρ_0$=0.17~fm$^{-3}$, consistently with our previous results. Extrapolation to higher nuclear densities and possible relevance to the `hyperon puzzle' in neutron-star matter are discussed.
description: 19 pages, 7 figures, 4 tables, minor changes, published in Nucl. Phys. A 1039 (2023) 122725; doi.org/10.1016/j.nuclphysa.2023.122725
Long-period oscillations of active region patterns: least-squares mapping on second-order curves
Creators: name: Dumbadze, G.
name: Shergelashvili, B. M.
name: Kukhianidze, V.
name: Ramishvili, G.
name: Zaqarashvili, T. V.
name: Khodachenko, M.
name: Gurgenashvili, E.
name: Poedts, S.
name: De Causmaecker, P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Active regions (ARs) are the main sources of variety in solar dynamic events. Automated detection and identification tools need to be developed for solar features for a deeper understanding of the solar cycle. Of particular interest here are the dynamical properties of the ARs, regardless of their internal structure and sunspot distribution. We studied the oscillatory dynamics of two ARs: NOAA 11327 and NOAA 11726 using two different methods of pattern recognition. We developed a novel method of automated AR border detection and compared it to an existing method for the proof-of-concept. The first method uses least-squares fitting on the smallest ellipse enclosing the AR, while the second method applies regression on the convex hull.} After processing the data, we found that the axes and the inclination angle of the ellipse and the convex hull oscillate in time. These oscillations are interpreted as the second harmonic of the standing long-period kink oscillations (with the node at the apex) of the magnetic flux tube connecting the two main sunspots of the ARs. In both ARs we have estimated the distribution of the phase speed magnitude along the magnetic tubes (along the two main spots) by interpreting the obtained oscillation of the inclination angle as the standing second harmonic kink mode. After comparing the obtained results for fast and slow kink modes, we conclude that both of these modes are good candidates to explain the observed oscillations of the AR inclination angles, as in the high plasma $β$ regime the phase speeds of these modes are comparable and on the order of the Alfvén speed. Based on the properties of the observed oscillations, we detected the appropriate depth of the sunspot patterns, which coincides with estimations made by helioseismic methods. The latter analysis can be used as a basis for developing a magneto-seismological tool for ARs.
description: 10 pages, 6 figures, Accepted for publication in A&A
Enhanced proton acceleration in an applied longitudinal magnetic field
Creators: name: Arefiev, Alexey
name: Toncian, Toma
name: Fiksel, Gennady
Publisher: name: arXiv
Year: 2016
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Using two-dimensional particle-in-cell simulations, we examine how an externally applied strong magnetic impacts proton acceleration in laser-irradiated solid-density targets. We find that a kT-level external magnetic field can sufficiently inhibit transverse transport of hot electrons in a flat laser-irradiated target. While the electron heating by the laser remains mostly unaffected, the reduced electron transport during proton acceleration leads to an enhancement of maximum proton energies and the overall number of energetic protons. The resulting proton beam is much better collimated compared to a beam generated without applying a kT-level magnetic field. A factor of three enhancement of the laser energy conversion efficiency into multi-MeV protons is another effect of the magnetic field. The required kT magnetic fields are becoming feasible due to a significant progress that has been made in generating magnetic fields with laser-driven coils using ns-long laser pulses. The predicted improved characteristics of laser-driven proton beams would be critical for a number of applications.
Modeling the early afterglow in the short and hard GRB 090510
Creators: name: Fraija, Nissim
name: Lee, William H.
name: Veres, Peter
name: Duran, Rodolfo Barniol
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The bright, short and hard GRB 090510 was detected by all instruments aboard Fermi and Swift satellites. The multiwavelength observations of this burst presented similar features with the Fermi-LAT-detected gamma-ray bursts. In the framework of the external shock model of early afterglow, a leptonic scenario that evolves in a homogeneous medium is proposed to revisit GRB 090510 and explain the multiwavelength light curve observations presented in this burst. These observations are consistent with the evolution of a jet before and after the jet break. The long-lasting LAT, X-ray and optical fluxes are explained in the synchrotron emission from the adiabatic forward shock. Synchrotron self-Compton emission from the reverse shock is consistent with the bright LAT peak provided that progenitor environment is entrained with strong magnetic fields. It could provide compelling evidence of magnetic field amplification in the neutron star merger.
description: 9 pages and 4 figures. Accepted for publication in ApJ
An irradiated-Jupiter analogue hotter than the Sun
Creators: name: Hallakoun, Na'ama
name: Maoz, Dan
name: Istrate, Alina G.
name: Badenes, Carles
name: Breedt, Elmé
name: Gänsicke, Boris T.
name: Jha, Saurabh W.
name: Leibundgut, Bruno
name: Mannucci, Filippo
name: Marsh, Thomas R.
name: Nelemans, Gijs
name: Patat, Ferdinando
name: Rebassa-Mansergas, Alberto
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Planets orbiting close to hot stars experience intense extreme-ultraviolet radiation, potentially leading to atmosphere evaporation and to thermal dissociation of molecules. However, this extreme regime remains mainly unexplored due to observational challenges. Only a single known ultra-hot giant planet, KELT-9b, receives enough ultraviolet radiation for molecular dissociation, with a day-side temperature of ~4,600K. An alternative approach uses irradiated brown dwarfs as hot-Jupiter analogues. With atmospheres and radii similar to those of giant planets, brown dwarfs orbiting close to hot Earth-sized white-dwarf stars can be directly detected above the glare of the star. Here we report observations revealing an extremely irradiated low-mass companion to the hot white dwarf WD0032-317. Our analysis indicates a day-side temperature of ~8,000K, and a day-to-night temperature difference of ~6,000K. The amount of extreme-ultraviolet radiation (with wavelengths 100-912Å) received by WD0032-317B is equivalent to that received by planets orbiting close to stars as hot as a late B-type stars, and about 5,600 times higher than that of KELT-9b. With a mass of ~75-88 Jupiter masses, this near-hydrogen-burning-limit object is potentially one of the most massive brown dwarfs known.
description: Authors' version of the article published in Nature Astronomy (DOI https://doi.org/10.1038/s41550-023-02048-z)
On the de Rham-Wu decomposition for Riemannian and Lorentzian manifolds
Creators: name: Galaev, Anton S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Differential Geometry (math.DG)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: It is explained how to find the de~Rham decomposition of a Riemannian manifold and the Wu decomposition of a Lorentzian manifold. For that it is enough to find parallel symmetric bilinear forms on the manifold, and do some linear algebra. This result will allow to compute the connected holonomy group of an arbitrary Riemannian or Lorentzian manifold.
description: 9 pages; this is an extanded version of a part from arXiv:1110.1998 that was published