cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Nanocables made of a transition metal wire and boron nitride sheath: Density functional calculations
Creators: name: Lu, J.P.
name: Zhao, J.
name: Yang, C.-K.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2006

description: The boron nitride (BN) nanotube has a very wide band gap and can shield the nanowire encapsulated inside its cavity from outside interference. Our calculations indicate that transition metal wires can be inserted inside a variety of zigzag BN nanotubes exothermically. In particular a cobalt wire and the BN tube interact just like two giant molecules. The weak interaction between the BN tube and the wire ensures a low binding energy and a high magnetic moment that comes solely from the transition metals. High spin polarization at the Fermi level also indicates that the hybrid structure can be used as a nanocable for spintronic applications
Combined model for $\rm ^{15}N$, $\rm ^{13}C$, and spin-state chemistry in molecular clouds
Creators: name: Sipilä, O.
name: Colzi, L.
name: Roueff, E.
name: Caselli, P.
name: Fontani, F.
name: Wirström, E.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present a new gas-grain chemical model for the combined isotopic fractionation of carbon and nitrogen in molecular clouds, in which the isotope chemistry of carbon and nitrogen is coupled with a time-dependent description of spin-state chemistry. We updated the rate coefficients of some isotopic exchange reactions considered in the literature, and present here a set of new exchange reactions involving molecules substituted in $\rm ^{13}C$ and $\rm ^{15}N$ simultaneously. We apply the model to a series of zero-dimensional simulations representing a set of physical conditions across a prototypical prestellar core, exploring the deviations of the isotopic abundance ratios in the various molecules from the elemental isotopic ratios as a function of physical conditions and time. We find that the $\rm ^{12}C/^{13}C$ ratio can deviate from the elemental ratio by up to a factor of several depending on the molecule, and that there are highly time-dependent variations in the ratios. The $\rm HCN/H^{13}CN$ ratio, for example, can obtain values of less than 10 depending on the simulation time. The $\rm ^{14}N/^{15}N$ ratios tend to remain close to the assumed elemental ratio within $\sim$ ten per cent, with no clear trends as a function of the physical conditions. Abundance ratios between $\rm ^{13}C$-containing molecules and $\rm ^{13}C$+$\rm ^{15}N$-containing molecules show somewhat increased levels of fractionation due to the newly included exchange reactions, though still remaining within a few tens of per cent of the elemental $\rm ^{14}N/^{15}N$ ratio. Our results imply the existence of gradients in isotopic abundance ratios across prestellar cores, suggesting that detailed simulations are required to interpret observations of isotopically substituted molecules correctly, especially given that the various isotopic forms of a given molecule do not necessarily trace the same gas layers.
description: Accepted to A&A; abstract abridged to meet arXiv requirements
New 1-step extension of the Swanson oscillator and superintegrability of its two-dimensional generalization
Creators: name: Bagchi, Bijan
name: Marquette, Ian
Publisher: name: arXiv
Year: 2015
Subjects: subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We derive a one-step extension of the well known Swanson oscillator that describes a specific type of pseudo-Hermitian quadratic Hamiltonian connected to an extended harmonic oscillator model. Our analysis is based on the use of the techniques of supersymmetric quantum mechanics and address various representations of the ladder operators starting from a seed solution of the harmonic oscillator given in terms of a pseudo-Hermite polynomial. The role of the resulting chain of Hamiltonians related via similarity transformation is then exploited. In the second part we write down a two dimensional generalization of the Swanson Hamiltonian and establish superintegrability of such a system.
description: accepted for publication in Physics Letters A
Forgotten treasures in the HST/FOC UV imaging polarimetric archives of active galactic nuclei. I. Pipeline and benchmarking against NGC~1068 and exploring IC~5063
Creators: name: Barnouin, Thibault
name: Marin, Frédéric
name: Lopez-Rodriguez, Enrique
name: Huber, Léo
name: Kishimoto, Makoto
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences
subject: J.2; I.4.1; I.4.7; I.6.4
subject: 85-04 (Primary), 85-08, 85A25 (Secondary)

description: Over its 13 years of operation (1990 -- 2002), the Faint Object Camera (FOC) on board the Hubble Space Telescope (HST) observed 26 individual active galactic nuclei (AGNs) in ultraviolet (UV) imaging polarimetry. However, not all of the observations have been reduced and analyzed or set within a standardized framework. We plan to reduce and analyze the AGN observations that have been neglected in the FOC archives using a consistent, novel, and open-access reduction pipeline of our own. We then extend the method to the full AGN sample, thus leading to potential discoveries in the near future. We developed a new pipeline in Python that will be able to reduce all the FOC observations in imaging polarimetry in a homogeneous way. Most of the previously published reduced observations are dispersed throughout the literature, with the range of different analyses and approaches making it difficult to fully interpret the FOC AGN sample. By standardizing the method, we have enabled a coherent comparison among the different observational sets. In this first paper of a series exploring the full HST/FOC AGN sample, we present an exhaustively detailed account of how to properly reduce the observational data. Current progress in data-analysis is implemented in and has provided state-of-the-art UV polarimetric maps. We compare our new maps to the benchmark AGN case of NGC~1068 and successfully reproduce the main results previously published, while pushing the polarimetric exploration of this AGN futher, thanks to a finer resolution and a higher signal-to-noise ratio (S/N) than previously reported. We also present, for the first time, an optical polarimetric map of the radio-loud AGN IC~5063 and we examine the complex interactions between the AGN outflows and the surrounding interstellar medium (ISM).
description: 17 pages, 19 figures, to be published in Astronomy & Astrophysics
Historisch-kritische Theologie und Glaube
Creators: name: Grabner-Haider, Anton
Publisher: name: Internationale katholische Zeitschrift Communio
Year: 2022

description: Internationale katholische Zeitschrift Communio, Bd. 3 Nr. 2 (1974): Internationale katholische Zeitschrift Communio, Band 3, Heft 2
Geometric distortion of area in medical ultrasound images
Creators: name: Bland, T.
name: Tong, J.
name: Ward, B.
name: Parker, N. G.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Medical ultrasound scanners are typically calibrated to the soft tissue average of 1540 m s$^{-1}$. In regions of different sound speed, for example, organs and tumours, the $B$-scan image then becomes a distortion of the true tissue cross-section, due to the misrepresentation of length and refraction. To quantify this distortion we develop a general geometric ray model for an object with an atypical speed of sound embedded in an ambient medium. We analyse the ensuing area distortion for circular and elliptical objects, mapping it out as a function of the key parameters, including the speed of sound mismatch, the object size and its elongation. We find that the area distortion can become significant, even for small-scale speed of sound mismatches. Our findings are verified by ultrasound imaging of a test object.
description: Reduced in length, modified title
Optical Observations of Meteors Generating Infrasound - II: Weak Shock Theory and Validation
Creators: name: Silber, Elizabeth A.
name: Brown, Peter G.
name: Krzeminski, Zbigniew
Publisher: name: arXiv
Year: 2014
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We have recorded a dataset of 24 centimeter-sized meteoroids detected simultaneously by video and infrasound to critically examine the ReVelle [1974] weak shock meteor infrasound model. We find that the effect of gravity wave perturbations to the wind field and updated absorption coefficients in the linear regime on the initial value of the blast radius (R0), which is the strongly non-linear zone of shock propagation near the body and corresponds to energy deposition per path length, is relatively small. Using optical photometry for ground-truth for energy deposition, we find that the ReVelle model accurately predicts blast radii from infrasound periods (τ), but systematically under-predicts R0 using pressure amplitude. If the weak shock to linear propagation distortion distance is adjusted as part of the modelling process we are able to self-consistently fit a single blast radius value for amplitude and period. In this case, the distortion distance is always much less (usually just a few percent) than the value of 10 percent assumed in the ReVelle model. Our study shows that fragmentation is an important process even for centimeter sized meteoroids, implying that R0, while a good measure of energy deposition by the meteoroid, is not a reliable means of obtaining the meteoroid mass. We derived an empirical period-blast radius relation appropriate to cm sized meteoroids. Our observations suggest that meteors having blast radii as small as 1m are detectable infrasonically at the ground, an order of magnitude smaller than previously considered.
description: 58 pages, 14 figures, 5 tables
Marche du roi René jouée au galoubet-tambourin par Fabre père et fils
Creators: name: Musée National Des Arts Et Traditions Populaires (Paris)
name: Centre D'ethnologie Française
Publisher: name: École des Hautes Études en Sciences Sociales; Institut  interdisciplinaire d'anthropologie du contemporain (Paris); Laboratoire d'anthropologie et d'histoire de l'institution de la culture (Paris)
Year: 2024

Abstract
Conservation laws in the $1f_{7/2}$ shell model of $^{48}$Cr
Creators: name: Neergård, K.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Conservation laws in the $1f_{7/2}$ shell model of $^{48}$Cr found in numeric studies by Escuderos, Zamick and Bayman [A. Escuderos, L. Zamick, and B. F. Bayman, arXiv:0506050 (2005)] and me [K. Neergård, Phys. Rev. C \textbf{90}, 014318 (2014)] are explained by symmetry under particle-hole conjugation and the structure of the irreps of the symplectic group Sp(4). A generalization is discussed.
description: Some typos corrected
Webinar: Ocean observations and predictions (Presentations and recording), #ClimateThursday Webinar, 22 October 2020
Creators: name: Grist, Hannah
name: Berx, Barbara
name: Keenlyside, Noel
name: Payne, Mark R.
name: Bearzotti, Chiara
Publisher: name: Zenodo
Year: 2020
Subjects: Climate services, earth system models, fisheries, ocean observing

description: The Blue-Action team presented a webinar on 22nd October 2020 as part of Climateurope #ClimateThursday webinar series on climate services. The topic was "Ocean observations and predictions in response to the climate emergency", including presentations from Barbara Berx (Marine Scotland), Noel Keenlyside (University of Bergen) and Mark R. Payne (DTU).
Polarized radiation from an accretion shock in accreting millisecond pulsars using exact Compton scattering formalism
Creators: name: Bobrikova, Anna
name: Loktev, Vladislav
name: Salmi, Tuomo
name: Poutanen, Juri
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Pulse profiles of accreting millisecond pulsars can be used to determine neutron star (NS) parameters, such as their masses and radii, and therefore provide constraints on the equation of state of cold dense matter. Information obtained by the Imaging X-ray Polarimetry Explorer (IXPE) can be used to decipher pulsar inclination and magnetic obliquity, providing ever tighter constraints on other parameters. In this paper, we develop a new emission model for accretion-powered millisecond pulsars based on thermal Comptonization in an accretion shock above the NS surface. The shock structure was approximated by an isothermal plane-parallel slab and the Stokes parameters of the emergent radiation were computed as a function of the zenith angle and energy for different values of the electron temperature, the Thomson optical depth of the slab, and the temperature of the seed blackbody photons. We show that our Compton scattering model leads to a significantly lower polarization degree of the emitted radiation compared to the previously used Thomson scattering model. We computed a large grid of shock models, which can be combined with pulse profile modeling techniques both with and without polarization included. In this work, we used the relativistic rotating vector model for the oblate NS in order to produce the observed Stokes parameters as a function of the pulsar phase. Furthermore, we simulated the data to be produced by IXPE and obtained constraints on model parameters using nested sampling. The developed methods can also be used in the analysis of the data from future satellites, such as the enhanced X-ray Timing and Polarimetry mission.
description: Accepted to A&A on 11 August 2023
Practical management of mild-to-moderate ulcerative colitis: an international expert consensus
Creators: name: D’Amico, Ferdinando
name: Magro, Fernando
name: Dignass, Axel
name: Al Awadhi, Sameer
name: Casbas, Ana Gutierrez
name: Queiroz, Natália Sousa Freitas
name: Rydzewska, Grażyna
name: Ye, Byong Duk
name: Ran, Zhihua
name: Hart, Ailsa
name: Jairath, Vipul
name: Fiorino, Gionata
name: Peyrin-Biroulet, Laurent
name: Danese, Silvio
Publisher: name: Taylor & Francis
Year: 2024
Subjects: subject: Medicine
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Sociology
subject: FOS: Sociology
subject: Immunology
subject: FOS: Clinical medicine
subject: Cancer
subject: Infectious Diseases
subject: FOS: Health sciences

description: Although there are well-defined guidelines for the management of mild-to-moderate ulcerative colitis (UC), there are still unmet needs. For this reason, we conducted an international expert consensus to standardize the management of patients with mild-to-moderate UC and provide practical guidance to clinicians. Based on Delphi methodology, 15 statements were approved after two rounds of voting, addressing several aspects of disease management from sequencing to treatment duration, from monitoring to optimization techniques and safety profile. Growing knowledge of mild-to-moderate UC has led to the development of new ambitious outcomes such as histological remission and disease clearance. Furthermore, noninvasive tools for patient monitoring such as fecal calprotectin and intestinal ultrasound are now available. Their implementation in clinical practice will allow clinicians to tightly monitor disease activity and promptly adapt treatment, avoiding complications and disease progression and targeting better disease control.
Quantum interference effects in electronic transport through nanotube contacts
Creators: name: Lu, J.P.
name: Buia, C.
name: Buldum, A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2003

description: Quantum interference has dramatic effects on electronic transport through nanotube contacts. In optimal configuration the intertube conductance can approach that of a perfect nanotube (formula presented) The maximum conductance increases rapidly with the contact length up to 10 nm, beyond which it exhibits long-wavelength oscillations. This is attributed to the resonant interference phenomena in the contact region. For two concentric nanotubes symmetry breaking can reduce the maximum intertube conductance from (formula presented) to (formula presented) The phenomena discussed here can serve as a foundation for building nanotube electronic circuits and high-speed nanoscale electromechanical devices.
Fehlbar oder unfehlbar? Zu Küngs Bilanz der Debatte
Creators: name: Horn, Stephan Otto
Publisher: name: Internationale katholische Zeitschrift Communio
Year: 2022

description: Internationale katholische Zeitschrift Communio, Bd. 3 Nr. 1 (1974): Internationale katholische Zeitschrift Communio, Band 3, Heft 1
Monads and distributive laws for Rota-Baxter and differential algebras
Creators: name: Guo, Li
name: Keigher, William
name: Zhang, Shilong
Publisher: name: arXiv
Year: 2014
Subjects: subject: Category Theory (math.CT)
subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 18C15, 13N99, 16W99

description: In recent years, algebraic studies of the differential calculus and integral calculus in the forms of differential algebra and Rota-Baxter algebra have been merged together to reflect the close relationship between the two calculi through the First Fundamental Theorem of Calculus. In this paper we study this relationship from a categorical point of view in the context of distributive laws which can be tracked back to the distributive law of multiplication over addition. The monad giving Rota-Baxter algebras and the comonad giving differential algebras are constructed. Then a mixed distributive law of the monad over the comonad is established. As a consequence, we obtain monads and comonads giving the composite structures of differential and Rota-Baxter algebras.
description: 25 pages
An overview of the Internet of Things (IoT) Architecture
Creators: name: Isa A.I.
name: Muhammad A. B
Publisher: name: gjrpublication
Year: 2024

description: The convergence of multiple technologies, including machine learning, embedded systems, and commodity sensors, has substantially changed the term "IoT.". The Internet of Things (IoT) is a network of interconnected devices that have been assigned unique identifiers (UIDS) in order to enable device control and data transfer. It made direct human interaction with technology less necessary. The Internet of Things (IoT) is a sophisticated automation and analytics system that provides whole systems for a good or service by utilizing big data, artificial intelligence, networking, sensing, and sensing technologies. These systems facilitate improved performance, control, and transparency in any system or industry. A review of the Internet of Things (IoT) architecture is discussed in this article.
The Megamaser Cosmology Project. VI. Observations of NGC 6323
Creators: name: Kuo, C. Y.
name: Braatz, J. A.
name: Lo, K. Y.
name: Reid, M. J.
name: Suyu, S. H.
name: Pesce, D. W.
name: Condon, J. J.
name: Henkel, C.
name: Impellizzeri, C. M. V.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present observations of the H2O megamasers in the accretion disk of NGC 6323. By combining interferometric and spectral monitoring data, we estimate H$_{0} = 73^{+26}_{-22}$ km/s/Mpc, where the low strength of the systemic masers (<15 mJy) limits the accuracy of this estimate. The methods developed here for dealing with weak maser emission provide guidance for observations of similar sources, until significant increases in radio telescope sensitivity, such as anticipated from the next generation Very Large Array, are realized.
description: 17 pages, 7 figures, 4 tables; Accepted by ApJ; in press
Pattern Matching and Local Alignment for RNA Structures
Creators: name: Chen, Shihyen
name: Wang, Zhuozhi
name: Zhang, Kaizhong
Publisher: name: arXiv
Year: 2014
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Computer and information sciences

description: The primary structure of a ribonucleic acid (RNA) molecule can be represented as a sequence of nucleotides (bases) over the alphabet {A, C, G, U}. The secondary or tertiary structure of an RNA is a set of base pairs which form bonds between A-U and G-C. For secondary structures, these bonds have been traditionally assumed to be one-to-one and non-crossing. This paper considers pattern matching as well as local alignment between two RNA structures. For pattern matching, we present two algorithms, one for obtaining an exact match, the other for approximate match. We then present an algorithm for RNA local structural alignment.
description: 7 pages. V2: changed first names initials to full names in metadata. V3: added info of conference proceedings, updated email address
Die Kirchen in der Bundesrepublik Deutschland: innere Situation
Creators: name: Maier, Hans
Publisher: name: Internationale katholische Zeitschrift Communio
Year: 2022

description: Internationale katholische Zeitschrift Communio, Bd. 3 Nr. 1 (1974): Internationale katholische Zeitschrift Communio, Band 3, Heft 1
Extreme Tidal Stripping May Explain the Overmassive Black Hole in Leo I: a Proof of Concept
Creators: name: Pacucci, Fabio
name: Ni, Yueying
name: Loeb, Abraham
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: A recent study found dynamical evidence of a supermassive black hole of $\sim 3 \times 10^{6} \, \rm M_\odot$ at the center of Leo I, the most distant dwarf spheroidal galaxy of the Milky Way. This black hole, comparable in mass to the Milky Way's Sgr A*, places the system $>2$ orders of magnitude above the standard $M_\bullet-M_{\star}$ relation. We investigate the possibility, from a dynamical standpoint, that Leo I's stellar system was originally much more massive and, thus, closer to the relation. Extreme tidal disruption from one or two close passages within the Milky Way's virial radius could have removed most of its stellar mass. A simple analytical model suggests that the progenitor of Leo I could have experienced a mass loss in the range of $32\% - 57\%$ from a single pericenter passage, depending on the stellar velocity dispersion estimate. This mass loss percentage increases to the range $66\% - 78\%$ if the pericenter occurs at the minimum distance allowed by current orbital reconstructions. Detailed N-body simulations show that the mass loss could reach $\sim 90\%$ with up to two passages, again with pericenter distances compatible with the minimum value allowed by Gaia data. Despite very significant uncertainties in the properties of Leo I, we reproduce its current position and velocity dispersion, as well as the final stellar mass enclosed in $1$ kpc ($\sim 5\times 10^6 \, \rm M_\odot$) within a factor $< 2$. The most recent tidal stream is directed along our line of sight toward Leo I, making it difficult to detect. Evidence from this extreme tidal disruption event could be present in current Gaia data in the form of extended tidal streams.
description: Accepted for publication in The Astrophysical Journal Letters. 9 pages, 4 figures. A video of the N-body simulation can be viewed here: https://www.fabiopacucci.com/resources/simulations/
Magnetism of Transition-Metal/Carbon-Nanotube Hybrid Structures
Creators: name: Lu, J.P.
name: Zhao, J.
name: Yang, C.-K.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2003

description: It has long been established that by filling carbon nanotubes or coating on their surfaces with transition metals, one-dimensional hybrid nanostructures can be synthesized. We found through ab initio calculations that such transition-metal/nanotube hybrid structures exhibit substantial magnetism. In particular, cobalt atoms packed inside a variety of carbon nanotubes offer strong spin polarization at the Fermi level as well as considerable magnetic moments. The results point to a new and promising approach that uses such metal-filled carbon nanotubes as devices for spin-polarized transport and to potential applications in the emerging field of spintronics.
Complex AGN feedback in the Teacup galaxy. A powerful ionised galactic outflow, jet-ISM interaction, and evidence for AGN-triggered star formation in a giant bubble
Creators: name: Venturi, G.
name: Treister, E.
name: Finlez, C.
name: D'Ago, G.
name: Bauer, F.
name: Harrison, C. M.
name: Almeida, C. Ramos
name: Revalski, M.
name: Ricci, F.
name: Sartori, L. F.
name: Girdhar, A.
name: Keel, W. C.
name: Tubín, D.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The $z$~0.1 type-2 QSO J1430+1339 (the 'Teacup') is a complex galaxy showing a loop of ionised gas ~10 kpc in diameter, co-spatial radio bubbles, a compact (~1 kpc) jet, and outflow activity. We used VLT/MUSE optical integral field spectroscopic observations to characterise the properties and effects of the galactic ionised outflow from kpc up to tens of kpc scales and compare them with those of the radio jet. We detect a velocity dispersion enhancement (>300 km/s) elongated over several kpc perpendicular to the radio jet, the AGN ionisation lobes, and the fast outflow, similar to what is found in other galaxies hosting compact, low-power jets, indicating that the jet strongly perturbs the host ISM. The mass outflow rate decreases with distance from the nucleus, from around 100 $M_\odot$/yr in the inner 1-2 kpc to <0.1 $M_\odot$/yr at 30 kpc. The ionised mass outflow rate is ~1-8 times higher than the molecular one, in contrast with what is often quoted in AGN. The driver of the multi-phase outflow is likely a combination of AGN radiation and the jet. The outflow mass-loading factor (~5-10) and the molecular gas depletion time (<10$^8$ yr) indicate that the outflow can significantly affect the star formation and the gas reservoir in the galaxy. However, the fraction of the ionised outflow that is able to escape the dark matter halo potential is likely negligible. We detect blue-coloured continuum emission co-spatial with the ionised gas loop. Here, stellar populations are younger (<100-150 Myr) than in the rest of the galaxy (~0.5-1 Gyr). This constitutes possible evidence for star formation triggered at the edge of the bubble due to the compressing action of the jet and outflow ('positive feedback'), as predicted by theory. All in all, the Teacup constitutes a rich system in which AGN feedback from outflows and jets, in both its negative and positive flavours, co-exist.
description: 26 pages, 16 figures; Astronomy & Astrophysics, in press
Electron field emission properties of closed carbon nanotubes
Creators: name: Lu, J.P.
name: Buldum, A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2003

description: Recent experiments have shown that carbon nanotubes exhibit excellent electron field emisson properties with high current densities at low electric fields. Here we present theoretical investigations that incorporate geometrical effects and the electronic structure of nanotubes. The electric field is dramatically enhanced near the cap of a nanotube with a large variation of local field distribution. It is found that deviation from linear Fowler-Nordheim behavior occurs due to the variation of the local field in the electron tunneling region. The maximum current per tube is of the order of [Formula presented]. Local and microscopic aspects of field emission from nanotubes are also presented.
Classical Inflationary and Ekpyrotic Universes in the No-Boundary Wavefunction
Creators: name: Lehners, Jean-Luc
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: This paper investigates the manner in which classical universes are obtained in the no-boundary quantum state. In this context, universes can be characterised as classical (in a WKB sense) when the wavefunction is highly oscillatory, i.e. when the ratio of the change in the amplitude of the wavefunction becomes small compared to the change in the phase. In the presence of a positive or negative exponential potential, the WKB condition is satisfied in proportion to a factor $e^{-(ε- 3)N/(ε-1)},$ where $ε$ is the (constant) slow-roll/fast-roll parameter and $N$ designates the number of e-folds. Thus classicality is reached exponentially fast in $N$, but only when $ε< 1$ (inflation) or $ε> 3$ (ekpyrosis). Furthermore, when the potential switches off and the ekpyrotic phase goes over into a phase of kinetic domination, the level of classicality obtained up to that point is preserved. Similar results are obtained in a cyclic potential, where a dark energy plateau is added. Finally, for a potential of the form $-ϕ^n$ (with $n=4,6,8$), where the classical solution becomes increasingly kinetic-dominated, there is an initial burst of classicalisation which then quickly levels off. These results demonstrate that inflation and ekpyrosis, which are the only dynamical mechanisms known for smoothing the universe, share the perhaps even more fundamental property of rendering space and time classical in the first place.
description: 35 pages, 19 figures, v2: replaced with version to be published in PRD
Mesoscopic Bose-Einstein condensates as quantum simulators
Creators: name: Gallemí, A.
name: Guilleumas, M.
name: Mayol, R.
name: Sanpera, A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Mesoscopic interacting Bose-Einstein condensates confined in a few traps display phase transitions that cannot be explained with a mean field theory. By describing each trap as an effective site of a Bose-Hubbard model and using the Schwinger representation of spin operators, these systems can be mapped to spin models. We show that it is possible to define correlations between bosons in such a way that critical behavior is associated to the divergence of a correlation length accompanied by a gapless spectrum in the thermodynamic limit. The latter is now defined as the limit in which the mean field analysis becomes valid. Such description provides critical exponents to the associated phase transitions and encompasses the notion of universality demonstrating thus the potential use of mesoscopic Bose-Einstein condensates as quantum simulators of condensed matter systems.
description: 6 pages, 6 figures
A search for the afterglows, kilonovae, and host galaxies of two short GRBs: GRB 211106A and GRB 211227A
Creators: name: Ferro, M.
name: Brivio, R.
name: D'Avanzo, P.
name: Rossi, A.
name: Izzo, L.
name: Campana, S.
name: Christensen, L.
name: Dinatolo, M.
name: Hussein, S.
name: Levan, A. J.
name: Melandri, A.
name: Bernardini, M. G.
name: Covino, S.
name: D'Elia, V.
name: Della Valle, M.
name: De Pasquale, M.
name: Gompertz, B. P.
name: Hartmann, D.
name: Heintz, K. E.
name: Jakobsson, P.
name: Kouveliotou, C.
name: Malesani, D. B.
name: Martin-Carrillo, A.
name: Nava, L.
name: Guelbenzu, A. Nicuesa
name: Pugliese, G.
name: Salvaggio, C.
name: Salvaterra, R.
name: Savaglio, S.
name: Sbarrato, T.
name: Tanvir, N. R.
name: Wijers, R. A. M. J.
name: Zafar, T.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Context: GRB 211106A and GRB 211227A are recent gamma-ray bursts (GRBs) with initial X-ray positions suggesting associations with nearby galaxies (z < 0.7). Their prompt emission characteristics indicate GRB 211106A is a short-duration GRB and GRB 211227A is a short GRB with extended emission, likely originating from compact binary mergers. However, classifying solely based on prompt emission can be misleading. Aims: These short GRBs in the local Universe offer opportunities to search for associated kilonova (KN) emission and study host galaxy properties in detail. Methods: We conducted deep optical and NIR follow-up using ESO-VLT FORS2, HAWK-I, and MUSE for GRB 211106A, and ESO-VLT FORS2 and X-Shooter for GRB 211227A, starting shortly after the X-ray afterglow detection. We performed photometric analysis to look for afterglow and KN emissions associated with the bursts, along with host galaxy imaging and spectroscopy. Optical/NIR results were compared with Swift X-Ray Telescope (XRT) and other high-energy data. Results: For both GRBs we placed deep limits to the optical/NIR afterglow and KN emission. Host galaxies were identified: GRB 211106A at photometric z = 0.64 and GRB 211227A at spectroscopic z = 0.228. Host galaxy properties aligned with typical short GRB hosts. We also compared the properties of the bursts with the S-BAT4 sample to further examined the nature of these events. Conclusions: Study of prompt and afterglow phases, along with host galaxy analysis, confirms GRB 211106A as a short GRB and GRB 211227A as a short GRB with extended emission. The absence of optical/NIR counterparts is likely due to local extinction for GRB 211106A and a faint kilonova for GRB 211227A.
description: Accepted to A&A on 08 August 2023, 21 pages, 24 figures
Structure of Gamma-Ray Burst jets: intrinsic versus apparent properties
Creators: name: Salafia, O. S.
name: Ghisellini, G.
name: Pescalli, A.
name: Ghirlanda, G.
name: Nappo, F.
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: With this paper we introduce the concept of apparent structure of a GRB jet, as opposed to its intrinsic structure. The latter is customarily defined specifying the functions epsilon(theta) (the energy emitted per jet unit solid angle) and Gamma(theta) (the Lorentz factor of the emitting material); the apparent structure is instead defined by us as the isotropic equivalent energy E_iso(theta_v) as a function of the viewing angle theta_v. We show how to predict the apparent structure of a jet given its intrinsic structure. We find that a Gaussian intrinsic structure yields a power law apparent structure: this opens a new viewpoint on the Gaussian (which can be understood as a proxy for a realistic narrow, well collimated jet structure) as a possible candidate for a quasi-universal GRB jet structure. We show that such a model (a) is consistent with recent constraints on the observed luminosity function of GRBs; (b) implies fewer orphan afterglows with respect to the standard uniform model; (c) can break out the progenitor star (in the collapsar scenario) without wasting an unreasonable amount of energy; (d) is compatible with the explanation of the Amati correlation as a viewing angle effect; (e) can be very standard in energy content, and still yield a very wide range of observed isotropic equivalent energies.
description: 10 pages, 8 figures, 1 table. Accepted by MNRAS
Causes and treatment of pylostenosis
Creators: name: Ergasheva Nigorxon, Jo'rayeva Lobar
Publisher: name: Zenodo
Year: 2024

description: Annotation: Pyloric stenosis is an uncommon condition in infants that blocks food from entering the small intestine. Typically, a muscular valve between the stomach and small intestine holds food in the stomach until it is ready for the next stage in the digestive process. This valve is called the pylorus valve. In pyloric stenosis, the pylorus muscles thicken and become abnormally large, blocking food from reaching the small intestine.

Key words: puloric, food, disease, baby,stenosis,muscles, stomach.
An efficient dissipative particle dynamics-based algorithm for simulating electrolyte solutions
Creators: name: Medina, Stefan
name: Zhou, Jiajia
name: Wang, Zhen-Gang
name: Schmid, Friederike
Publisher: name: arXiv
Year: 2014
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We propose an efficient simulation algorithm based on the dissipative particle dynamics (DPD) method for studying electrohydrodynamic phenomena in electrolyte fluids. The fluid flow is mimicked with DPD particles while the evolution of the concentration of the ionic species is described using Brownian pseudo particles. The method is designed especially for systems with high salt concentrations, as explicit treatment of the salt ions becomes computationally expensive. For illustration, we apply the method to electro-osmotic flow over patterned, superhydrophobic surfaces. The results are in good agreement with recent theoretical predictions.
description: Typos in equations and references corrected; Journal of Chemical Physics, at press
Black Holes in Higher-Derivative Gravity
Creators: name: Lu, H.
name: Perkins, A.
name: Pope, C. N.
name: Stelle, K. S.
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Extensions of Einstein gravity with higher-order derivative terms arise in string theory and other effective theories, as well as being of interest in their own right. In this paper we study static black-hole solutions in the example of Einstein gravity with additional quadratic curvature terms. A Lichnerowicz-type theorem simplifies the analysis by establishing that they must have vanishing Ricci scalar curvature. By numerical methods we then demonstrate the existence of further black-hole solutions over and above the Schwarzschild solution. We discuss some of their thermodynamic properties, and show that they obey the first law of thermodynamics.
description: Typos corrected, discussion added, figure changed. 4 pages, 6 figures
$\sin^2θ^{\rm lept}_{\rm eff}$ and $M_W$(indirect) extracted from 9 fb$^{-1}$ $μ^+μ^-$ event sample at CDF
Creators: name: Bodek, A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We report on the extraction of $\sin^2θ^{\rm lept}_{\rm eff}$ and indirect measurement of the mass of the W boson from the forward-backward asymmetry of $μ^+μ^-$ events in the $Z$ boson mass region. The data sample collected by the CDF detector corresponds to the full 9 fb$^{-1}$ run II sample. We measure $\sin^2 θ^{\rm lept}_{\rm eff} = 0.2315 \pm 0.0010$, $ \sin^2 θ_W = 0.2233 \pm 0.0009$ and $M_W ({\rm indirect}) = 80.365 \pm 0.047 \;{\rm GeV}/c^2$, where each uncertainty includes both statistical and systematic contributions. Comparison with the results of the D0 collaboration are presented.
description: To be published in the proceedings of the 37th International Conference on High-Energy Physics, ICHEP 2014 6 pages, 3 figures
Vibrational modes of carbon nanotubes and nanoropes
Creators: name: Lu, J.P.
name: Kahn, D.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 1999

description: The vibrational modes of carbon nanotubes and nanoropes are studied. The Raman and infrared active modes are determined for armchair, zigzag, and chiral nanotubes. High-energy Raman and infrared modes exhibit distinct characteristic patterns for armchair, zigzag, and chiral tubes. In the nanorope the intertube interactions shifts the energy of certain vibrational modes dramatically. This has implications when using the vibrational spectra to identify tubes. In the nanorope we find Raman modes exhibit shifts under a change in pressure which differ from the corresponding shifts found in graphite.
X-ray luminosity-star formation rate scaling relation: Constraints from the eROSITA Final Equatorial Depth Survey (eFEDS)
Creators: name: Riccio, G.
name: Yang, G.
name: Małek
name: Boquien, M.
name: Junais
name: Pistis, F.
name: Hamed, M.
name: Grespan, M.
name: Paolillo, M.
name: Torbaniuk, O.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present measurements of the relation between X-ray luminosity and star formation activity for a sample of normal galaxies spanning the redshift range between 0 and 0.25. We use data acquired by SRG/eROSITA for the performance and verification phase program called eROSITA Final Equatorial Depth Survey (eFEDS). The eFEDS galaxies are observed in the 0.2-2.3 keV band. Making use of a wide range of ancillary data, spanning from the ultraviolet (UV) to mid-infrared wavelengths (MIR), we estimated the star formation rate (SFR) and stellar mass ($M_{star}$) of 888 galaxies, using Code Investigating GALaxy Emission (CIGALE). We divided our sample of normal galaxies in star-forming (SFGs) and quiescent galaxies according to their position on the main sequence. We confirm a linear correlation between the X-ray luminosity and the SFR for our sample of SFGs, as shown previously in the literature. However, we find this relation to be strongly biased by the completeness limit of the eFEDS survey. Correcting for completeness, we find the fitted relation to be consistent with the literature. We also investigated the relation between X-ray emission from both LMXBs and HMXBs populations with $M_{star}$ and SFR, respectively. Correcting for completeness, we find our fitted relation to considerably scatter from the literature relation at high specific SFR ($SFR/M_{star}$). We conclude that without accounting for X-ray non-detections, it is not possible to employ eFEDS data to study the redshift evolution of the LMXBs and HMXBs contributions due to completeness issues. Furthermore, we find our sources to largely scatter from the expected Lx/SFR vs specific SFR relation at high redshift. We discuss the dependence of the scatter on the stellar mass, metallicity, or the globular cluster content of the galaxy.
description: Accepted for publication in A&A
Conformal Fermi Coordinates
Creators: name: Dai, Liang
name: Pajer, Enrico
name: Schmidt, Fabian
Publisher: name: arXiv
Year: 2015
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Fermi Normal Coordinates (FNC) are a useful frame for isolating the locally observable, physical effects of a long-wavelength spacetime perturbation. Their cosmological application, however, is hampered by the fact that they are only valid on scales much smaller than the horizon. We introduce a generalization that we call Conformal Fermi Coordinates (CFC). CFC preserve all the advantages of FNC, but in addition are valid outside the horizon. They allow us to calculate the coupling of long- and short-wavelength modes on all scales larger than the sound horizon of the cosmological fluid, starting from the epoch of inflation until today, by removing the complications of the second order Einstein equations to a large extent, and eliminating all gauge ambiguities. As an application, we present a calculation of the effect of long-wavelength tensor modes on small scale density fluctuations. We recover previous results, but clarify the physical content of the individual contributions in terms of locally measurable effects and "projection" terms.
description: 43 pages, two figures. v2: minor changes, added references, expanded subsec 3.3
No strong radio absorption detected in the low-frequency spectra of radio-loud quasars at z > 5.6
Creators: name: Gloudemans, A. J.
name: Saxena, A.
name: Intema, H.
name: Callingham, J. R.
name: Duncan, K. J.
name: Rottgering, H. J. A.
name: Belladitta, S.
name: Hardcastle, M. J.
name: Harikane, Y.
name: Spingola, C.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the low-frequency radio spectra of 9 high-redshift quasars at $5.6 \leq z \leq 6.6$ using the Giant Metre Radio Telescope band-3, -4, and -5 observations ($\sim$300-1200 MHz), archival Low Frequency Array (LOFAR; 144 MHz), and Very Large Array (VLA; 1.4 and 3 GHz) data. Five of the quasars in our sample have been discovered recently, representing some of the highest redshift radio bright quasars known at low-frequencies. We model their radio spectra to study their radio emission mechanism and age of the radio jets by constraining the spectral turnover caused by synchrotron self-absorption (SSA) or free-free absorption (FFA). Besides J0309+2717, a blazar at $z=6.1$, our quasars show no sign of a spectral flattening between 144 MHz and a few GHz, indicating there is no strong SSA or FFA absorption in the observed frequency range. However, we find a wide range of spectral indices between $-1.6$ and $0.05$, including the discovery of 3 potential ultra-steep spectrum quasars. Using further archival VLBA data, we confirm that the radio SED of the blazar J0309+2717 likely turns over at a rest-frame frequency of 0.6-2.3 GHz (90-330 MHz observed frame), with a high-frequency break indicative of radiative ageing of the electron population in the radio lobes. Ultra-low frequency data below 50 MHz are necessary to constrain the absorption mechanism for J0309+2717 and the turnover frequencies for the other high-$z$ quasars in our sample. A relation between linear radio jet size and turnover frequency has been established at low redshifts. If this relation were to hold at high redshifts, the limits on the turnover frequency of our sample suggest the radio jet sizes must be more extended than the typical sizes observed in other radio-bright quasars at similar redshift. To confirm this deep radio follow-up observations with high spatial resolution are required.
description: 15 pages, 7 figures, accepted for publication in A&A, minor correction Tab. 1
Atomic scale sliding and rolling of carbon nanotubes
Creators: name: Lu, J.P.
name: Buldum, A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 1999

description: Using molecular statics and dynamics methods we investigate the motion of nanotubes on a graphite surface. Each nanotube has unique equilibrium orientations with sharp potential energy minima which lead to atomic scale locking of the nanotube. The effective contact area and the total interaction energy scale with the square root of the radius. Sliding and rolling nanotubes have different characters. The potential energy barriers for sliding nanotubes are higher than that for perfect rolling. When the nanotube is pushed, we observe a combination of atomic scale spinning and sliding motion.
Electromagnetic precursors to black hole - neutron star gravitational wave events: Flares and reconnection-powered fast-radio transients from the late inspiral
Creators: name: Most, Elias R.
name: Philippov, Alexander A.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The presence of magnetic fields in the late inspiral of black hole -- neutron star binaries could lead to potentially detectable electromagnetic precursor transients. Using general-relativistic force-free electrodynamics simulations, we investigate pre-merger interactions of the common magnetosphere of black hole -- neutron star systems. We demonstrate that these systems can feature copious electromagnetic flaring activity, which we find depends on the magnetic field orientation but not on black hole spin. Due to interactions with the surrounding magnetosphere, these flares could lead to Fast Radio Burst-like transients and X-ray emission, with $\mathcal{L}_{\rm EM} \lesssim 10^{41} \left( B_\ast/ 10^{12}\, \rm G \right)^2\, \rm erg/ s$ as an upper bound for the luminosity, where $B_\ast$ is the magnetic field strength on the surface of the neutron star.
description: 13 pages, 6 figures; accepted version, to appear in ApJL