cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
D2.2 – Report on the final release of the I/O library.
Creators: name: Scemama, Anthony
Publisher: name: Zenodo
Year: 2021
Subjects: QMC
TREX codes

description: A report for the progress of this Work Package (WP) was made in month 6: D2.1 - Report on the first alpha release of the I/O library, ready for WP4. We recall in this section the key points of the developed library. The objective of the TREX Input/Output (TREXIO) library is to facilitate inter-operability between codes in the field of quantum chemistry, primarily focused on enabling the communication of data between the flagship codes of the Targeting REal chemical accuracy at the eXascale (TREX) Center of Excellence (CoE): Neci, GammCor, Quantum Package, QMC=Chem, Champ,
 TurboRVB. In the long term, we expect this library to be also adopted by codes outside of the CoE. Data is read from or written to files in which the electronic wave function, reduced density matrices, integrals, etc. are stored, and an Application Programming Interface (API) is provided to store and retrieve the data in the files. To maximize the portability of the library, the source code is
 written in the C99 language, and it is released under the BSD-3 clause license.
Intention und Reflexion eines Neapel-Fahrtberichts
Creators: name: Busch, Anna Katharina
name: Lemke, Julia
Publisher: name: Latein und Griechisch in Nordrhein-Westfalen
Year: 2022

description: Latein und Griechisch in Nordrhein-Westfalen, Bd. 1 Nr. 1 (2020): Tag der offenen Tür
Departure of high temperature iron lines from the equilibrium state in flaring solar plasmas
Creators: name: Kawate, Tomoko
name: Keenan, Francis P.
name: Jess, David B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The aim of this study is to clarify if the assumption of ionization equilibrium and a Maxwellian electron energy distribution is valid in flaring solar plasmas. We analyze the 2014 December 20 X1.8 flare, in which the \ion{Fe}{xxi} 187~Å, \ion{Fe}{xxii} 253~Å, \ion{Fe}{xxiii} 263~Å and \ion{Fe}{xxiv} 255~Å emission lines were simultaneously observed by the EUV Imaging Spectrometer onboard the Hinode satellite. Intensity ratios among these high temperature Fe lines are compared and departures from isothermal conditions and ionization equilibrium examined. Temperatures derived from intensity ratios involving these four lines show significant discrepancies at the flare footpoints in the impulsive phase, and at the looptop in the gradual phase. Among these, the temperature derived from the \ion{Fe}{xxii}/\ion{Fe}{xxiv} intensity ratio is the lowest, which cannot be explained if we assume a Maxwellian electron distribution and ionization equilibrium, even in the case of a multi-thermal structure. This result suggests that the assumption of ionization equilibrium and/or a Maxwellian electron energy distribution can be violated in evaporating solar plasma around 10~MK.
description: 10 pages, 4 figures, to appear in ApJ
A Catalogue of Radio Supernova Remnants and Candidate Supernova Remnants in the EMU/POSSUM Galactic Pilot Field
Creators: name: Ball, Brianna D.
name: Kothes, Roland
name: Rosolowsky, Erik
name: West, Jennifer
name: Becker, Werner
name: Filipović, Miroslav D.
name: Gaensler, B. M.
name: Hopkins, Andrew M.
name: Koribalski, Bärbel
name: Landecker, Tom
name: Leahy, Denis
name: Marvil, Joshua
name: Sun, Xiaohui
name: Bufano, Filomena
name: Carretti, Ettore
name: Ingallinera, Adriano
name: Van Eck, Cameron L.
name: Willis, Tony
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We use data from the pilot observations of the EMU/POSSUM surveys to study the "missing supernova remnant (SNR) problem", the discrepancy between the number of Galactic SNRs that have been observed and the number that are estimated to exist. The Evolutionary Map of the Universe (EMU) and the Polarization Sky Survey of the Universe's Magnetism (POSSUM) are radio sky surveys that are conducted using the Australian Square Kilometre Array Pathfinder (ASKAP). We report on the properties of 7 known SNRs in the joint Galactic pilot field, with an approximate longitude and latitude of 323$^\circ\leq$ l $\leq$ 330$^\circ$ and -4$^\circ\leq$ b $\leq$ 2$^\circ$ respectively, and identify 21 SNR candidates. Of these, 4 have been previously identified as SNR candidates, 3 were previously listed as a single SNR, 13 have not been previously studied, and 1 has been studied in the infrared. These are the first discoveries of Galactic SNR candidates with EMU/POSSUM and, if confirmed, they will increase the SNR density in this field by a factor of 4. By comparing our SNR candidates to the known Galactic SNR population, we demonstrate that many of these sources were likely missed in previous surveys due to their small angular size and/or low surface brightness. We suspect that there are SNRs in this field that remain undetected due to limitations set by the local background and confusion with other radio sources. The results of this paper demonstrate the potential of the full EMU/POSSUM surveys to uncover more of the missing Galactic SNR population.
Sieg beim Wettbewerb "Aus der Welt der Griechen"
Creators: name: Kramme, Max
Publisher: name: Latein und Griechisch in Nordrhein-Westfalen
Year: 2022

description: Latein und Griechisch in Nordrhein-Westfalen, Bd. 1 Nr. 1 (2020): Tag der offenen Tür
title: Market structure of cryptoasset exchanges: Introduction, challenges and emerging trends
Creators: name: Skavysh, Vladimir
name: Sharples, Jacob
name: Priazhkina, Sofia
name: Hasham, Salman H.
Publisher: name: Bank of Canada
publisherIdentifier: https://ror.org/05cc98565
publisherIdentifierScheme: ROR
Year: 2024

description: This paper provides an overview of cryptoasset exchanges. We contrast their design with exchanges in traditional financial markets and discuss emerging regulatory trends and innovations aimed at solving the problems cryptoasset exchanges face.

description: Cette étude présente une vue d’ensemble des plateformes d’échange de cryptoactifs, que nous comparons aux bourses des marchés financiers traditionnels. Nous discutons aussi des tendances réglementaires émergentes ainsi que des innovations visant à résoudre les problèmes rencontrés par ces plateformes.
The Tianyi Model of "Dark Night"Astronomical Popular Science Education Activities for Teenagers
Creators: name: Shen, Xinrong
name: Shen, Zhouyi
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: The Tianyi Model of "Dark Night"Astronomical Popular Science Education Activities for Teenagers

Presenters: Shen Xinrong (Jiangsu Tianyi High School; Jiangsu Autonomous Learning Institute, China) and Zhouyi Shen (Wuxi Tianyi Experimental School, China)

 

This was a poster presented at the 5th Shaw-IAU Workshop on Astronomy for Education, organised by the IAU Office of Astronomy for Education (OAE, http//astro4edu.org).

The Astronomical Society of Jiangsu Tianyi High School has carried out practical exploration around "Dark Night", forming a popular science education model with a progressive curriculum design including popularisation, academic and research courses. This model stimulates students' interest through science popularization courses, consolidates students' knowledge through academiccourses, and guides students to solve problems through research courses. Over the past decade, the Tianyi model has achieved remarkable results. A number of papers on "Dark Night" have been published in SCI and other academic journals in and out of China, and a number of related projects have won awards in the academic competitions in and out of China.

About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

Keep up to date with future Shaw-IAU Workshops and other opportunities at the IAU Office of Astronomy for Education by joining our mailing list https://astro4edu.org/mailing-list/

Follow the IAU OAE on X and Facebook under @astro4edu
Variability of stellar granulation and convective blueshift with spectral type and magnetic activity. I. K and G main sequence stars
Creators: name: Meunier, N.
name: Lagrange, A. -M.
name: Kabuiku, L. Mbemba
name: Alex, M.
name: Mignon, L.
name: Borgniet, S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In solar-type stars, the attenuation of convective blueshift by stellar magnetic activity dominates the RV variations over the low amplitude signal induced by low mass planets. Models of stars that differ from the Sun will require a good knowledge of the attenuation of the convective blueshift to estimate its impact on the variations. It is therefore crucial to precisely determine not only the amplitude of the convective blueshift for different types of stars, but also the dependence of this convective blueshift on magnetic activity, as these are key factors in our model producing the RV. We studied a sample of main sequence stars with spectral types from G0 to K2 and focused on their temporally averaged properties: the activity level and a criterion allowing to characterise the amplitude of the convective blueshift. We find the differential velocity shifts of spectral lines due to convection to depend on the spectral type, the wavelength (this dependence is correlated with the Teff and activity level), and on the activity level. This allows us to quantify the dependence of granulation properties on magnetic activity for stars other than the Sun. The attenuation factor of the convective blueshift appears to be constant over the considered range of spectral types. We derive a convective blueshift which decreases towards lower temperatures, with a trend in close agreement with models for Teff lower than 5800 K, but with a significantly larger global amplitude. We finally compare the observed RV variation amplitudes with those that could be derived from our convective blueshift using a simple law and find a general agreement on the amplitude. Our results are consistent with previous results and provide, for the first time, an estimation of the convective blueshift as a function of Teff, magnetic activity, and wavelength, over a large sample of G and K main sequence stars.
Oriented spanning trees and stationary distribution of digraphs
Creators: name: Zhou, Jiang
name: Bu, Changjiang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Combinatorics (math.CO)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 05C30, 05C50, 05C05, 05C81, 05C20

description: By using biclique partitions of digraphs, this paper gives reduction formulas for the number of oriented spanning trees, stationary distribution vector and Kemeny's constant of digraphs. As applications, we give a method for enumerating spanning trees of undirected graphs by vertex degrees and biclique partitions. The biclique partition formula also extends the results of Knuth and Levine from line digraphs to general digraphs.
Artificial Neural Network and Time Series Modeling Based Approach to Forecasting the Exchange Rate in a Multivariate Framework
Creators: name: Chaudhuri, Tamal Datta
name: Ghosh, Indranil
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Finance (q-fin.ST)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Economics and business
subject: FOS: Computer and information sciences

description: Any discussion on exchange rate movements and forecasting should include explanatory variables from both the current account and the capital account of the balance of payments. In this paper, we include such factors to forecast the value of the Indian rupee vis a vis the US Dollar. Further, factors reflecting political instability and lack of mechanism for enforcement of contracts that can affect both direct foreign investment and also portfolio investment, have been incorporated. The explanatory variables chosen are the 3 month Rupee Dollar futures exchange rate (FX4), NIFTY returns (NIFTYR), Dow Jones Industrial Average returns (DJIAR), Hang Seng returns (HSR), DAX returns (DR), crude oil price (COP), CBOE VIX (CV) and India VIX (IV). To forecast the exchange rate, we have used two different classes of frameworks namely, Artificial Neural Network (ANN) based models and Time Series Econometric models. Multilayer Feed Forward Neural Network (MLFFNN) and Nonlinear Autoregressive models with Exogenous Input (NARX) Neural Network are the approaches that we have used as ANN models. Generalized Autoregressive Conditional Heteroskedastic (GARCH) and Exponential Generalized Autoregressive Conditional Heteroskedastic (EGARCH) techniques are the ones that we have used as Time Series Econometric methods. Within our framework, our results indicate that, although the two different approaches are quite efficient in forecasting the exchange rate, MLFNN and NARX are the most efficient.
Bundeswettbewerb Fremdsprachen Latein
Creators: name: Rink, Ulrike
Publisher: name: Latein und Griechisch in Nordrhein-Westfalen
Year: 2022

description: Latein und Griechisch in Nordrhein-Westfalen, Bd. 1 Nr. 1 (2020): Tag der offenen Tür
Observational Constraints on First-Star Nucleosynthesis. II. Spectroscopy of an Ultra Metal-Poor CEMP-no Star
Creators: name: Placco, Vinicius M.
name: Frebel, Anna
name: Beers, Timothy C.
name: Yoon, Jinmi
name: Chiti, Anirudh
name: Heger, Alexander
name: Chan, Conrad
name: Casey, Andrew R.
name: Christlieb, Norbert
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 report on the first high-resolution spectroscopic analysis of HE0020-1741, a bright (V=12.9), ultra metal-poor ([Fe/H] = -4.1), carbon-enhanced ([C/Fe] = +1.7) star selected from the Hamburg/ESO Survey. This star exhibits low abundances of neutron-capture elements ([Ba/Fe] = -1.1), and an absolute carbon abundance A(C) = 6.1; based on either criterion, HE0020-1741 is sub-classified as a CEMP-no star. We show that the light-element abundance pattern of HE0020-1741 is consistent with predicted yields from a massive (M = 21.5 Mo), primordial composition, supernova (SN) progenitor. We also compare the abundance patterns of other ultra metal-poor stars from the literature with available measures of C, N, Na, Mg, and Fe abundances with an extensive grid of SN models (covering the mass range 10 Mo - 100 Mo), in order to probe the nature of their likely stellar progenitors. Our results suggest that at least two classes of progenitors are required at [Fe/H] < -4.0, as the abundance patterns for more than half of the sample studied in this work (7 out of 12 stars) cannot be easily reproduced by the predicted yields.
description: 14 pages, 5 figures; accepted for publication in ApJ
Teaching Astronomy With the GoChile Project
Creators: name: Japelj, Jure
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Teaching Astronomy With the GoChile Project

Presenter: Jure Japelj (Center for Astrophysics and Cosmology, University of Nova Gorica, Slovenia)

Collaborators:Andreja Gomboc (Center for Astrophysics and Cosmology, University of Nova Gorica, Slovenia)

 

This was a poster presented at the 5th Shaw-IAU Workshop on Astronomy for Education, organised by the IAU Office of Astronomy for Education (OAE, http//astro4edu.org).

University of Nova Gorica (Slovenia) and astronomical magazine Spika run the GoChile project, which uses two small telescopes at the El Sauce Observatory in Chile. The two remotely operated telescopes are primarily intended for teaching—significant telescope time is reserved for secondary school students interested in astronomy. Through the project the students gain experience in observations and get introduced to the process of scientific research. I will present our activities in the past two years: remote teaching, mentoring of research projects and the organization of two summer schools. Interestingly, there has been a great interest in the telescope among girls, which was particularly evident in the summer schools, where more than half of the registrants and participants were girls.

About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

Keep up to date with future Shaw-IAU Workshops and other opportunities at the IAU Office of Astronomy for Education by joining our mailing list https://astro4edu.org/mailing-list/

Follow the IAU OAE on X and Facebook under @astro4edu
Präsentation des Profils Latein plus am Tag der offenen Tür
Creators: name: Rink, Ulrike
Publisher: name: Latein und Griechisch in Nordrhein-Westfalen
Year: 2022

description: Latein und Griechisch in Nordrhein-Westfalen, Bd. 1 Nr. 1 (2020): Tag der offenen Tür
High-Dimensional Quantum Key Distribution based on Multicore Fiber using Silicon Photonic Integrated Circuits
Creators: name: Ding, Yunhong
name: Bacco, Davide
name: Dalgaard, Kjeld
name: Cai, Xinlun
name: Zhou, Xiaoqi
name: Rottwitt, Karsten
name: Oxenløwe, Leif Katsuo
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum Key Distribution (QKD) provides an efficient means to exchange information in an unconditionally secure way. Historically, QKD protocols have been based on binary signal formats, such as two polarisation states, and the transmitted information efficiency of the quantum key is intrinsically limited to 1 bit/photon. Here we propose and experimentally demonstrate, for the first time, a high-dimensional QKD protocol based on space division multiplexing in multicore fiber using silicon photonic integrated lightwave circuits. We successfully realized three mutually unbiased bases in a four-dimensional Hilbert space, and achieved low and stable quantum bit error rate well below both coherent attack and individual attack limits. Compared to previous demonstrations, the use of a multicore fiber in our protocol provides a much more efficient way to create high-dimensional quantum states, and enables breaking the information efficiency limit of traditional QKD protocols. In addition, the silicon photonic circuits used in our work integrate variable optical attenuators, highly efficient multicore fiber couplers, and Mach-Zehnder interferometers, enabling manipulating high-dimensional quantum states in a compact and stable means. Our demonstration pave the way to utilize state-of-the-art multicore fibers for long distance high-dimensional QKD, and boost silicon photonics for high information efficiency quantum communications.
description: Please see the complementary work arXiv:1610.01682 (2016)
Black hole mining in the RST model
Creators: name: Basavaraju, Rohitvarma
name: Lowe, David A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We consider the possibility of mining black holes in the 1+1-dimensional dilaton gravity model of Russo, Susskind and Thorlacius. The model correctly incorporates Hawking radiation and back-reaction in a semiclassical expansion in 1/N, where N is the number of matter species. It is shown that the lifetime of a perturbed black hole is independent of the addition of any extra apparatus when realized by an arbitrary positive energy matter source. We conclude that mining does not occur in the RST model and comment on the implications of this for the black hole information paradox.
description: 14 pages, 3 figures
Palaearctic origin and repeated dispersal over the world shaped the biogeographic history of the saprophytic genus Coprinopsis (Psathyrellaceae, Basidiomycota)
Creators: name: Letícia Botura Schünemann, Bárbara
name: Reginato, Marcelo
name: Silveira, Rosa Mara Borges da
Publisher: name: Zenodo
Year: 2024
Subjects: Fungi
Coprinoid
Macroevolution
historical biogeography
Diversification
dating
Eocene

description: Aim: The biogeographic history of most fungi is still poorly known, as well as the patterns and processes responsible for their diversification. Recent studies uncovered that most fungi have originated and present higher diversification rates in the temperate zone. The distributional pattern known for fungi is also different from many plants, animals and microbes. Using the most comprehensive phylogeny of the saprotrophic genus Coprinopsis, we aim to infer the biogeographic history and test evolutionary hypotheses in the genus.

Location: Worldwide

Taxon: Fungi, Basidiomycota, Psathyrellaceae, Coprinopsis

Methods: We used a four-gene alignment with 100 species to estimate divergence times using two fossil calibrations within Agaricales. The chronograms were used to estimate diversification rates and geographic state-dependent models were applied. We further reconstructed the ancestral range history of the genus.

Results: Molecular dating estimated that the genus has diverged ca. 41 Ma (Eocene) and originated in the Palaearctic region. Diversification rates showed a decreasing pattern towards the present across Coprinopsis, especially after the Miocene (ca. 14 Ma). The diversification models dependent on distribution showed cosmopolitan lineages with higher net-diversification rates. When we compared temperate and tropical regions, we found that temperate lineages have higher net-diversification rates. The biogeographic history of Coprinopsis estimated different routes of dispersal. The most common dispersal route was from the Palaearctic to the Nearctic (15 times), followed by the Palaeartic to the Neotropics (14 times).

Main Conclusions: The study is the first to estimate the diversification rates and the historical biogeography of the coprinoid genus Coprinopsis. The diversification dynamics estimates in Coprinopsis are in agreement with the "generalized diversification rates model", where we found higher diversification rates in temperate regions compared to tropical regions. In general, the ancestral area and major dispersal routes recovered in the genus are similar to findings in other groups of fungi.
description: Funding provided by: Coordenação de Aperfeicoamento de Pessoal de Nível SuperiorCrossref Funder Registry ID: https://ror.org/00x0ma614Award Number:
Funding provided by: National Council for Scientific and Technological DevelopmentCrossref Funder Registry ID: https://ror.org/03swz6y49Award Number:
Microbubbles and microparticles are not faithful tracers of turbulent acceleration
Creators: name: Mathai, Varghese
name: Calzavarini, Enrico
name: Brons, Jon
name: Sun, Chao
name: Lohse, Detlef
Publisher: name: arXiv
Year: 2016
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We report on the Lagrangian statistics of acceleration of small (sub-Kolmogorov) bubbles and tracer particles with Stokes number St << 1 in turbulent flow. At decreasing Reynolds number, the bubble accelerations show deviations from that of tracer particles, i.e. they deviate from the Heisenberg-Yaglom prediction and show a quicker decorrelation despite their small size and minute St. Using direct numerical simulations, we show that these effects arise due the drift of these particles through the turbulent flow. We theoretically predict this gravity-driven effect for developed isotropic turbulence, with the ratio of Stokes to Froude number or equivalently the particle drift-velocity governing the enhancement of acceleration variance and the reductions in correlation time and intermittency. Our predictions are in good agreement with experimental and numerical results. The present findings are relevant to a range of scenarios encompassing tiny bubbles and droplets that drift through the turbulent oceans and the atmosphere. They also question the common usage of micro-bubbles and micro-droplets as tracers in turbulence research.
description: Physical Review Letters (accepted): 5 pages and ssupplemental material
Vorstellung des Faches Griechisch am Tag der offenen Tür im Neuen Gymnasium Bochum
Creators: name: Aretz, Susanne
Publisher: name: Latein und Griechisch in Nordrhein-Westfalen
Year: 2022

description: Latein und Griechisch in Nordrhein-Westfalen, Bd. 1 Nr. 1 (2020): Tag der offenen Tür
Code-Knacker: Geheime Nachricht aus dem antiken Rom
Creators: name: Habig, Jana
Publisher: name: Latein und Griechisch in Nordrhein-Westfalen
Year: 2022

description: Latein und Griechisch in Nordrhein-Westfalen, Bd. 1 Nr. 1 (2020): Tag der offenen Tür
Information zu den Schnupperheften (Buddybooks)
Creators: name: Aretz, Susanne
Publisher: name: Latein und Griechisch in Nordrhein-Westfalen
Year: 2022

description: Latein und Griechisch in Nordrhein-Westfalen, Bd. 1 Nr. 1 (2020): Tag der offenen Tür
Schokoriegel als Kriegsgott
Creators: name: Rogosch, Jonas
name: Willmann, Kristina
Publisher: name: Latein und Griechisch in Nordrhein-Westfalen
Year: 2022

description: Latein und Griechisch in Nordrhein-Westfalen, Bd. 1 Nr. 1 (2020): Tag der offenen Tür
Faster Block Tree Construction
Creators: name: Köppl, Dominik
name: Kurpicz, Florian
name: Meyer, Daniel
Publisher: name: Schloss Dagstuhl - Leibniz-Zentrum für Informatik (LZI)
Year: 2023
Subjects: compressed data structure
block tree
Lempel-Ziv compression
longest previous factor array
rank and select
Theory of computation → Data compression
Theory of computation → Pattern matching

description: The block tree [Belazzougui et al. J. Comput. Syst. Sci. '21] is a compressed text index that can answer access (extract a character at a position), rank (number of occurrences of a specified character in a prefix of the text), and select (size of smallest prefix such that a specified character has a specified rank) queries. It requires O(zlog(n/z)) words of space, where z is the number of Lempel-Ziv factors of the text. For some highly repetitive inputs, a block tree can require as little as 0.015 bits per character of the text. Small values of z make the block tree a space-efficient alternative to the wavelet tree, which is another index for these three types of queries. While wavelet trees can be constructed fast in practice, up so far compressed versions of the wavelet tree only leverage statistical compression, meaning that they are blind to spaced repetitions. To make block trees usable in practice, a first step is to find ways in constructing them efficiently. We address this problem by presenting a practically efficient construction algorithm for block trees, which is up to an order of magnitude faster than previous implementations. Additionally, we parallelize our implementation, making it the first block tree construction implementation that works in parallel in shared memory.
Quantum Cloning of Binary Coherent States - Optimal Transformations and Practical Limits
Creators: name: Müller, Christian R.
name: Leuchs, Gerd
name: Marquardt, Christoph
name: Andersen, Ulrik L.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The notions of qubits and coherent states correspond to different physical systems and are described by specific formalisms. Qubits are associated with a two-dimensional Hilbert space and can be illustrated on the Bloch sphere. In contrast, the underlying Hilbert space of coherent states is infinite-dimensional and the states are typically represented in phase space. For the particular case of binary coherent state alphabets these otherwise distinct formalisms can equally be applied. We capitalize this formal connection to analyse the properties of optimally cloned binary coherent states. Several practical and near-optimal cloning schemes are discussed and the associated fidelities are compared to the performance of the optimal cloner.
description: 12 pages, 12 figures
Wigner crystal phases in confined carbon nanotubes
Creators: name: Sarkany, Lorinc
name: Szirmai, Edina
name: Moca, Catalin Pascu
name: Glazman, Leonid
name: Zarand, Gergely
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present a detailed theoretical analysis of the Wigner crystal states in confined semiconducting carbon nanotubes. We show by robust scaling arguments as well as by detailed semi-microscopic calculations that the effective exchange interaction has an SU(4) symmetry, and can reach values even as large as $J\sim 100 {\rm \,K}$ in weakly screened, small diameter nanotubes, close to the Wigner crystal - electron liquid crossover. Modeling the nanotube carefully and analyzing the magnetic structure of the inhomogeneous electron crystal, we recover the experimentally observed 'phase boundaries' of Deshpande and Bockrath [V. V. Deshpande and M. Bockrath, Nature Physics $\mathbf 4$, 314 (2008)]. Spin-orbit coupling only slightly modifies these phase boundaries, but breaks the spin symmetry down to SU(2)$\times$SU(2), and in Wigner molecules it gives rise to interesting excitation spectra, reflecting the underlying SU(4) as well as the residual SU(2)$\times$SU(2) symmetries.
description: 14 pages, 13 figures
Control of Exciton Valley Coherence in Transition Metal Dichalcogenide Monolayers
Creators: name: Wang, G.
name: Marie, X.
name: Liu, B. L.
name: Amand, T.
name: Robert, C.
name: Cadiz, F.
name: Renucci, P.
name: Urbaszek, B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The direct gap interband transitions in transition metal dichalcogenides monolayers are governed by chiral optical selection rules. Determined by laser helicity, optical transitions in either the $K^+$ or $K^-$ valley in momentum space are induced. Linearly polarized laser excitation prepares a coherent superposition of valley states. Here we demonstrate the control of the exciton valley coherence in monolayer WSe2 by tuning the applied magnetic field perpendicular to the monolayer plane. We show rotation of this coherent superposition of valley states by angles as large as 30 degrees in applied fields up to 9 T. This exciton valley coherence control on ps time scale could be an important step towards complete control of qubits based on the valley degree of freedom.
description: 5 pages, 2 figures
Structural and electronic properties of ultrathin FeSe films grown on Bi$_2$Se$_3$(0001) studied by STM/STS
Creators: name: Singh, U. R.
name: Warmuth, J.
name: Markmann, V.
name: Wiebe, J.
name: Wiesendanger, R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We report scanning tunnelling microscopy and spectroscopy (STM/STS) studies on one and two unit cell (UC) high FeSe thin films grown on Bi$_2$Se$_3$(0001). In our thin films, we find the tetragonal phase of FeSe and dumb-bell shaped defects oriented along Se-Se bond directions. In addition, we observe striped moiré patterns with a periodicity of ($7.3\pm 0.1$) nm generated by the mismatch between the FeSe lattice and the Bi$_2$Se$_3$ lattice. We could not find any signature of a superconducting gap in the tunneling spectra measured on the surface of one and two UC thick islands of FeSe down to 6.5 K. The spectra rather show an asymmetric behavior across and a finite density of states at the Fermi level ($E_F$) resembling those taken in the normal state of bulk FeSe.
description: 19 pages and 4 figures
An experimental and theoretical investigation of the C(1D) + D2 reaction
Creators: name: Hickson, Kevin M.
name: Suleimanov, Yury V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: In a previous joint experimental and theoretical study of the barrierless chemical reaction C(1D) + H2 at low temperatures (300-50 K) [K. M. Hickson, J.-C. Loison, H. Guo, Y. V. Suleimanov, J. Phys. Chem. Lett., 2015, 6, 4194.], excellent agreement was found between experimental thermal rate constants and theoretical estimates based on ring polymer molecular dynamics (RPMD) over the two lowest singlet potential energy surfaces (PESs). Here, we extend this work to one of its deuterated counterparts, C(1D) + D2, over the same temperature range. Experimental and RPMD results are in very good agreement when contributions from both PESs to this chemical reaction are included in the RPMD simulations. The deviation between experiment and the RPMD calculations does not exceed 25 % and both results exhibit a slight negative temperature dependence. The first excited 1A" PES plays a more important role than the ground 1A' PES as the temperature is decreased, similar to our previous studies of the C(1D) + H2 reaction but with a more pronounced effect. The small differences in temperature dependence between the earlier and present experimental studies of C(1D) + H2/D2 reactions are discussed in terms of the use of non-equilibrium populations of ortho/para-H2/D2. We argue that RPMD provides a very convenient and reliable tool to study low-temperature chemical reactions.
Properties of Original Impactors Estimated from Three-Dimensional Analysis of Whole Stardust Tracks
Creators: name: Greenberg, Michael
name: Ebel, Denton S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The Stardust mission captured comet Wild 2 particles in aerogel at 6.1 km/sec. We performed high resolution three-dimensional imaging and X-ray fluorescence mapping of whole cometary tracks in aerogel. We present the results of a survey of track structures using Laser Scanning Confocal Microscopy, including measurements of track volumes, entry hole size and cross-sectional profiles. We compare various methods for measuring track parameters. We demonstrate a methodology for discerning hypervelocity particle ablation rates using synchrotron-based X-ray fluorescence, combined with mass and volume estimates of original impactors derived from measured track properties. Finally, we present a rough framework for reconstruction of original impactor size, and volume of volatilized material, using our measured parameters. The bulk of this work is in direct support of non-destructive analysis and identification of cometary grains in whole tracks, and its eventual application to the reconstruction of the size, shape, porosity and chemical composition of whole Stardust impactors.
description: 21 pages, 10 figures, 3 tables
Repurposing diabetes drugs for the treatment of intestinal helminth infection
Creators: name: Dooley, Megan
Publisher: name: Lancaster University
Year: 2022

description: Intestinal helminth infection affects over 1.5 billion people in the most deprived communities. These helminth infections cause significant morbidity, especially in children, with symptoms including malnutrition, stunted growth, and cognitive impairment. Resistance to current anthelminthic drugs is increasing, particularly in Trichuris trichiura “whipworm” infection, leading to the urgent need for new treatments. Recently, a group of immune cells at the intestinal barrier, intraepithelial lymphocytes (IELs), have been found to possess receptors for the epithelial produced peptide hormone, glucagon-like peptide-1(GLP-1). However, how these GLP-1 receptor (GLP-1r)+ IELs respond during infection is completely unknown. We used the mouse model of whipworm Trichuris muris to investigate whether already clinically approved GLP-1r agonist treatment could influence mice chronically infected with the parasite. We utilised GLP-1r reporter, receptor null (GLP-1rKO) and immunocompromised RAG-/- mice as well as flow cytometric cytokine and epithelial pulse chase turnover experiments. We found that GLP-1r+ IELs expand at the intestinal barrier in response to chronic Trichuris infection and ex vivo treatment of GLP-1r+ IELs with GLP-1r agonists favoured a Th2/Th1 cytokine balance. In vivo treatment of already chronically infected mice with GLP-1r agonists significantly increased epithelial turnover, a known mechanism of intestinal parasite expulsion. Excitingly, this was coupled with rapid expulsion of the parasite, which we did not observe when treating infected GLP-1rKO or RAG-/- mice. These data suggest that GLP-1 is modulating the local intestinal immune response through GLP-1r+ IELs to induce increased epithelial turnover and expulsion of the parasite, offering an exciting potential therapeutic option for Trichuriasis. Furthermore, use of GLP-1r agonists, already approved for use in diabetics, would allow a quick and simple repurposing for treatment of these helminth infections greatly improving the quality of life of many children in developing countries.
Understanding General Relativity after 100 years: A matter of perspective
Creators: name: Dadhich, Naresh
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: This is the centenary year of general relativity, it is therefore natural to reflect on what perspective we have evolved in 100 years. I wish to share here a novel perspective, and the insights and directions that ensue from it.
description: v1, 16pp; contribution to Paddy's Festschrift
Automatic Liver and Lesion Segmentation in CT Using Cascaded Fully Convolutional Neural Networks and 3D Conditional Random Fields
Creators: name: Christ, Patrick Ferdinand
name: Elshaer, Mohamed Ezzeldin A.
name: Ettlinger, Florian
name: Tatavarty, Sunil
name: Bickel, Marc
name: Bilic, Patrick
name: Rempfler, Markus
name: Armbruster, Marco
name: Hofmann, Felix
name: D'Anastasi, Melvin
name: Sommer, Wieland H.
name: Ahmadi, Seyed-Ahmad
name: Menze, Bjoern H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Automatic segmentation of the liver and its lesion is an important step towards deriving quantitative biomarkers for accurate clinical diagnosis and computer-aided decision support systems. This paper presents a method to automatically segment liver and lesions in CT abdomen images using cascaded fully convolutional neural networks (CFCNs) and dense 3D conditional random fields (CRFs). We train and cascade two FCNs for a combined segmentation of the liver and its lesions. In the first step, we train a FCN to segment the liver as ROI input for a second FCN. The second FCN solely segments lesions from the predicted liver ROIs of step 1. We refine the segmentations of the CFCN using a dense 3D CRF that accounts for both spatial coherence and appearance. CFCN models were trained in a 2-fold cross-validation on the abdominal CT dataset 3DIRCAD comprising 15 hepatic tumor volumes. Our results show that CFCN-based semantic liver and lesion segmentation achieves Dice scores over 94% for liver with computation times below 100s per volume. We experimentally demonstrate the robustness of the proposed method as a decision support system with a high accuracy and speed for usage in daily clinical routine.
description: Accepted at MICCAI 2016. Source code available on https://github.com/IBBM/Cascaded-FCN
The Origin of Chondrules: Constraints from Matrix-Chondrule Complementarity
Creators: name: Palme, Herbert
name: Hezel, Dominik C.
name: Ebel, Denton S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: One of the major unresolved problems in cosmochemistry is the origin of chondrules, once molten, spherical silicate droplets with diameters of 0.2 to 2 mm. Chondrules are an essential component of primitive meteorites and perhaps of all early solar system materials including the terrestrial planets. Numerous hypotheses have been proposed for their origin. Many carbonaceous chondrites are composed of about equal amounts of chondrules and fine-grained matrix. Recent data confirm that matrix in carbonaceous chondrites has high Si/Mg and Fe/Mg ratios when compared to bulk carbonaceous chondrites with solar abundance ratios. Chondrules have the opposite signature, low Si/Mg and Fe/Mg ratios. In some carbonaceous chondrites chondrules have low Al/Ti ratios, matrix has the opposite signature and the bulk is chondritic. It is shown in detail that these complementary relationships cannot have evolved on the parent asteroid(s) of carbonaceous chondrites. They reflect preaccretionary processes. Both chondrules and matrix must have formed from a single, solar-like reservoir. Consequences of complementarity for chondrule formation models are discussed. An independent origin and/or random mixing of chondrules and matrix can be excluded. Hence, complementarity is a strong constraint for all astrophysical-cosmochemical models of chondrule formation. Although chondrules and matrix formed from a single reservoir, the chondrule-matrix system was open to the addition of oxygen and other gaseous components.
description: 27 pages, 8 figures, with supplemental tables
Discovery of the high-entropy carbide ceramic topological superconductor candidate (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C
Creators: name: Zeng, Lingyong
name: Wang, Zequan
name: Song, Jing
name: Lin, Gaoting
name: Guo, Ruixin
name: Luo, Si-Chun
name: Guo, Shu
name: Li, Kuan
name: Yu, Peifei
name: Zhang, Chao
name: Guo, Wei-Ming
name: Ma, Jie
name: Hou, Yusheng
name: Luo, Huixia
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: High-entropy ceramics (HECs) are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements. Material design and property tailoring possibilities emerge from this new class of materials. Here, we report the discovery of superconductivity around 2.35 K and topological properties in the (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C high-entropy carbide ceramic (HECC), which has not been observed before in any of the investigated HECC. Density functional theory calculations showed that six type-II Dirac points exist in (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C, which mainly contributed from the t2g orbitals of transition metals and the p orbitals of C. Due to the stability of the structure, we also observed robust superconductivity under pressure in this HEC superconductor. This study expands the physical properties of HECs, which may become a new material platform for superconductivity research, especially for studying the coupling between superconductivity and topological physics.
description: 30 pages, 5 figures
Neutron star-black hole coalescence rate inferred from macronova/kilonova observations
Creators: name: Li, Xiang
name: Hu, Yi-Ming
name: Jin, Zhi-Ping
name: Fan, Yi-Zhong
name: Wei, Da-Ming
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Neutron star$-$black hole (NS$-$BH) coalescences are widely believed to be promising gravitational wave sources in the era of advanced detectors of LIGO/Virgo but such binaries have never been directly detected yet. Evidence for NS$-$BH coalescences have been suggested in short and hybrid GRB observations, which are examined critically. Based on the suggested connection between the observed macronovae/kilonovae events and NS$-$BH coalescences, we get a fiducial lower limit of NS$-$BH coalescence rate density ${\cal R}_{\rm nsbh} \approx 18.8^{+12.5}_{-8.6} ~{\rm Gpc^{-3}~ yr^{-1}~ (θ_j/0.1~{\rm rad})^{-2}}$, where $θ_{\rm j}$ is the typical half-opening angle of the GRB ejecta. The real value of ${\cal R}_{\rm nsbh}$ is likely at least $\sim {\rm a~few}$ times larger, depending upon the equation of state of NS material and the properties of the NS$-$BH system, such as the mass and spin distribution of the black hole. If the link between macronovae/kilonovae and NS$-$BH coalescence is valid, one can expect that at design sensitivity the aLIGO/AdVirgo network will detect NS$-$BH coalescence signals at a rate of at least a dozen per year, and to consequently place constraints on certain physical properties of NS$-$BH systems.
description: 5 pages, 1 table, 2 figures
Igniting the Astronomical Spark: Unconventional Approaches to Teaching Astronomy
Creators: name: Escobar Garcia, Carolina
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Igniting the Astronomical Spark: Unconventional Approaches to Teaching Astronomy

Presenter: Carolina Escobar Garcia (Galileo Teacher Training Program)

 

This was a poster presented at the 5th Shaw-IAU Workshop on Astronomy for Education, organised by the IAU Office of Astronomy for Education (OAE, http//astro4edu.org).

Even though in an ideal world everyone would have access to astronomy, that is not the reality for millions of people all over the world, and in Colombia, this happens even in the main cities of the country. Helios GTTP has created and carried out educational and outreach activities applying modeling instruction methodology and hands-on activities with communities that are not able to attend the planetarium or astronomy club´s activities and also are not considered the target audience because of geographical location, beliefs, or even prejudice.

About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

Keep up to date with future Shaw-IAU Workshops and other opportunities at the IAU Office of Astronomy for Education by joining our mailing list https://astro4edu.org/mailing-list/

Follow the IAU OAE on X and Facebook under @astro4edu
Reply to the Comment on "The Lifshitz-Matsubara sum formula for the Casimir pressure between magnetic metallic mirrors"
Creators: name: Guérout, R
name: Lambrecht, A
name: Milton, K A
name: Reynaud, S
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We reply to the "Comment on 'The Lifshitz-Matsubara sum formula for the Casimir pressure between magnetic metallic mirrors'" [arXiv:1604.06432]. We believe the comment misrepresents our papers, and fails to provide a plausible resolution to the conflict between theory and experiment.
description: To appear in Phys. Rev. E