cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Evolution of the structural, magnetic and electronic properties of the triple perovskite Ba$_{3}$CoIr$_{2}$O$_{9}$
Creators: name: Garg, Charu
name: Roy, Deepak
name: Lonsky, Martin
name: Manuel, Pascal
name: Cervellino, Antonio
name: Müller, Jens
name: Kabir, Mukul
name: Nair, Sunil
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report a comprehensive investigation of the triple perovskite iridate Ba$_{3}$CoIr$_{2}$O$_{9}$. Stabilizing in the hexagonal $P6_{3}/mmc$ symmetry at room temperature, this system transforms to a monoclinic $C2/c$ symmetry at the magnetic phase transition. On further reduction in temperature, the system partially distorts to an even lower symmetry ($P2/c$), with both these structurally disparate phases coexisting down to the lowest measured temperatures. The magnetic structure as determined from neutron diffraction data indicates a weakly canted antiferromagnetic structure, which is also supported by first-principles calculations. Theory indicates that the Ir$^{5+}$ carries a finite magnetic moment, which is also consistent with the neutron data. This suggests that the putative $J=0$ state is avoided. Measurements of heat capacity, electrical resistance noise and dielectric susceptibility all point towards the stabilization of a highly correlated ground state in the Ba$_{3}$CoIr$_{2}$O$_{9}$ system.
Effect of the break-up on the fusion and elastic scattering of weakly bound projectiles on $^{64}$Zn
Creators: name: Gomes, P. R. S.
name: Rodriguez, M. D.
name: Marti, C. V.
name: Padron, I.
name: Chamon, L. C.
name: Niello, J. O. Fernandez
name: Capurro, O. A.
name: Pacheco, A. J.
name: Testoni, J. E.
name: Arazi, A.
name: Ramirez, M.
name: Anjos, R. M.
name: Lubian, J.
name: Viega, R.
name: Neto, R. Liguori
name: Crema, E.
name: Added, N.
name: Tenreiro, C.
name: Hussein, M. S.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We study the behavior of the fusion, break-up, reaction and elastic scattering of different projectiles on $^{64}$Zn, at near and above barrier energies. We present fusion and elastic scattering data with the tightly bound $^{16}$O and the stable weakly bound $^{6}$Li, $^{7}$Li and $^{9}$Be projectiles. The data were analyzed by coupled channel calculations. The total fusion cross sections for these systems are not affected by the break-up process at energies above the barrier. The elastic (non-capture) break-up cross section is important at energies close and above the Coulomb barrier and increases the reaction cross sections. In addition we also show that the break-up process at near and sub-barrier energies is responsible for the vanishing of the usual threshold anomaly of the optical potential and give rise to a new type of anomaly.
description: 24 pages, 10 figures
MIDDLE JURASSIC NAUTILOIDEA FROM WESTERN FRANCE
Creators: name: BRANGER, PATRICK
Publisher: name: Università degli Studi di Milano
Year: 2004

description: The Middle Jurassic shelf margin limestones and marly limestones of Western France yield quite numerous Nautilida. This record is here described for the first time in detail, nine genera and more than forty species, whose range rarely exceeds one or two ammonite biozones, constitute a rather precise tool to date Middle Jurassic beds. Each taxon is placed in an accurate biostratigraphical chart; a new genus, Pictonautilus nov. gen., is described. The stratigraphical range of Cenoceras, Digonioceras and Gen. B n. ? (sensu Chirat 1997) is extended up to the Middle Callovian. In the Jurassic successions of Poitou, Nautilida always represent a minor part of the fossil record, they are more abundant in four levels: Middle Aalenian, base of Upper Bajocian, Lower Bathonian and top of Middle Bathonian. Dwarf Nautilida (Paracenoceras) and species showing more folded septa and a subventral siphuncle (Pseudaganides) or strongly ribbed specimens (Cymatonautilus) are characteristic of stable open-shelf environments (Callovian), whereas large shelled nautilus would be mostly present during deepening episodes. The geographical extension of many taxa indicates a provincialism that fits with that of ammonites of the same period.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 110, No 1
Dynamical frustration in ANNNI model and annealing
Creators: name: Sen, Parongama
name: Das, Pratap Kumar
Publisher: name: arXiv
Year: 2005
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Zero temperature quench in the Axial Next Nearest Neighbour Ising (ANNNI) model fails to bring it to its ground state for a certain range of values of the frustration parameter $κ$, the ratio of the next nearest neighbour antiferromagnetic interaction strength to the nearest neighbour one. We apply several annealing methods, both classical and quantum, and observe that the behaviour of the residual energy and the order parameter depends on the value of $κ$ strongly. Classical or thermal annealing is found to be adequate for small values of $κ$. However, neither classical nor quantum annealing is effective at values of $κ$ close to the fully frustrated point $κ=0.5$, where the residual energy shows a very slow algebraic decay with the number of MCS.
description: 6 pages,10 figures, to be published in Proceedings of " The International Workshop on Quantum annealing and other Optimization Methods"
The Dancing Sky: 6 years of night sky observations at Cerro Paranal
Creators: name: Patat, F.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The present work provides the results of the first six years of operation of the systematic night-sky monitoring at ESO-Paranal (Chile). The UBVRI night-sky brightness was estimated on about 10,000 VLT-FORS1 archival images, obtained on more than 650 separate nights, distributed over 6 years and covering the descent from maximum to minimum of sunspot cycle n.23. Additionally, a set of about 1,000 low resolution, optical night-sky spectra have been extracted and analyzed. The unprecedented database discussed in this paper has led to the detection of a clear seasonal variation of the broad band night sky brightness in the VRI passbands, similar to the well known semi-annual oscillation of the NaI D doublet. The spectroscopic data demonstrate that this seasonality is common to all spectral features, with the remarkable exception of the OH rotational-vibrational bands. A clear dependency on the solar activity is detected in all passbands and it is particularly pronounced in the U band, where the sky brightness decreased by about 0.6 mag arcsec-2 from maximum to minimum of solar cycle n.23. No correlation is found between solar activity and the intensity of the NaI D doublet and the OH bands. A strong correlation between the intensity of NI 5200A and [OI]6300,6364A is reported here for the first time. The paper addresses also the determination of the correlation timescales with solar activity and the possible connection with the flux of charged particles emitted by the Sun.
description: 19 pages, 27 figures, accepted for publication in Astronomy & Astrophysics. Full resolution version at http://www.hq.eso.org/~fpatat/science/skybright/paperIII.pdf
Quantum-Classical Transition of Photon-Carnot Engine Induced by Quantum Decoherence
Creators: name: Quan, H. T.
name: Zhang, P.
name: Sun, C. P.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the physical implementation of the Photon Carnot engine (PCE) based on the cavity QED system [M. Scully et al, Science, \textbf{299}, 862 (2003)]. Here, we analyze two decoherence mechanisms for the more practical systems of PCE, the dissipation of photon field and the pure dephasing of the input atoms. As a result we find that (I) the PCE can work well to some extent even in the existence of the cavity loss (photon dissipation); and (II) the short-time atomic dephasing, which can destroy the PCE, is a fatal problem to be overcome.
description: 6 pages, 3 figures
Elicitation of verb paradigms from unpublished Goddard material
Creators: name: Parker, Verdena
name: Spence, Justin
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2021
Subjects: subject: hup

description: Audio file VP-190919-06: Verb paradigm elicitation based on unpublished material transcribed by P.E. Goddard (Bancroft Library CU-23.1 12.14.1, file 2184-12 (4).pdf).
Analysis of Short Dwell Time in Relation to User Interest in a News Application
Creators: name: Homma, Ryosuke
name: Seki, Yoshifumi
name: Yoshida, Mitsuo
name: Umemura, Kyoji
Publisher: name: arXiv
Year: 2020
Subjects: subject: Information Retrieval (cs.IR)
subject: Digital Libraries (cs.DL)
subject: Social and Information Networks (cs.SI)
subject: FOS: Computer and information sciences

description: Dwell time has been widely used in various fields to evaluate content quality and user engagement. Although many studies shown that content with long dwell time is good quality, contents with short dwell time have not been discussed in detail. We hypothesize that content with short dwell time is not always low quality and does not always have low user engagement, but is instead related to user interest. The purpose of this study is to clarify the meanings of short dwell time browsing in mobile news application. First, we analyze the relation of short dwell time to user interest using large scale user behavior logs from a mobile news application. This analysis was conducted on a vector space based on users click histories and then users and articles were mapped in the same space. The users with short dwell time are concentrated on a specific position in this space; thus, the length of dwell time is related to their interest. Moreover, we also analyze the characteristics of short dwell time browsing by excluding these browses from their click histories. Surprisingly, excluding short dwell time click history, it was found that short dwell time click history included some aspect of user interest in 30.87% of instances where the cluster of users changed. These findings demonstrate that short dwell time does not always indicate a low level of user engagement, but also level of user interest.
description: The 2020 IEEE/WIC/ACM International Joint Conference on Web Intelligence and Intelligent Agent Technology (WI-IAT '20), Best in Practice Paper Award
THE MIDDLE JURASSIC EASTERN MARGIN OF THE IBERIAN PLATFORM SYSTEM (EASTERN SPAIN). PALAEOGEOGRAPHY AND BIODISPERSAL ROUTES OF AMMONOIDS
Creators: name: R. FERNÁNDEZ-LÓPEZ, SIXTO
name: J. GÓMEZ, JUAN
Publisher: name: Università degli Studi di Milano
Year: 2004

description: From a sedimentological and palaeogeographical point of view, in the eastern margin of the Iberian platform system, Middle Jurassic deposits are represented by a thick pile of carbonates with minor marls interbedded. Different facies, within the Tortosa, Aragonese and Castilian platforms, pertain to two categories: internal platform and external platform facies. A system of extensional faults was the major factor determining the differentiation of several shallow, carbonate, epicontinental platforms. The so-called Iberian Basin was a shallow intracratonic platform system, in which a relatively deep extensional basin (the Catalan Basin) started to be differentiated during the late Bajocian. In the eastern part of this faulted platform system, the occurrence of a listric fault, dipping towards the east, conditioned the development of a late Bajocian differentiated subsident area named the Tortosa Platform.
From a palaeobiogeographical point of view, the ammonite fossil assemblages of the Iberian platforms are composed of Sub-Mediterranean taxa. At the eastern margin of the Iberian platform system, the appearance and distribution of shells of ammonoids were taphonomically and ecologically controlled by regional changes of relative sea level. A Sub-Mediterranean zonation can be recognized, although most of the ammonites shells correspond to adult individuals arrived by necroplanktic drift from more open-marine or oceanic areas. The following criteria are relevant in recognizing the maximum deepening episodes in the Iberian platform system: colonization (including ontogenic development) of open-marine taxa, immigration of oceanic taxa and development of endemic species. In terms of Sequence Stratigraphy, the development of expanded, external platform sections in the Tortosa Platform during the Garantiana Biochron (late Bajocian) is noteworthy. During this episode, the Iberian platform system reached the maximum bathymetric values and acted as a biogeographical dispersal area for some taxonomic groups of ammonoids between the Western Tethys and the Proto-Atlantic.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 110, No 1
Resource-Constrained Project Scheduling: From a Lagrangian Relaxation to Competitive Solutions
Creators: name: Stork, Frederik
name: Uetz, Marc
Publisher: name: Technische Universität Berlin
Year: 2000
Subjects: subject: 510 Mathematik
subject: scheduling
subject: project scheduling
subject: Lagrangian relaxation
subject: list scheduling

description: List scheduling belongs to the classical and widely used algorithms for scheduling problems, but for resource-constrained project scheduling problems most standard priority lists do not capture enough of the problem structure, often resulting in poor performance. We use a well-known Lagrangian relaxation to first compute schedules which do not necessarily respect the resource constraints. We then apply list scheduling in the order of so-called α-completion times of jobs. Embedded into a standard subgradient optimization, our computational results show that the schedules compare to those obtained by state-of-the-art local search algorithms. In contrast to purely primal heuristics, however, the Lagrangian relaxation also provides powerful lower bounds, thus the deviation between lower and upper bounds can be drastically reduced by this approach.
Light-front dynamic analysis of the longitudinal charge density using the solvable scalar field model in (1+1) dimensions
Creators: name: Choi, Yongwoo
name: Choi, Ho-Meoyng
name: Ji, Chueng-Ryong
name: Oh, Yongseok
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We investigate the electromagnetic form factor $F(q^2)$ of the meson by using the solvable $ϕ^{3}$ scalar field model in $(1+1)$ dimensions. As the transverse rotations are absent in $(1+1)$ dimensions, the advantage of the light-front dynamics (LFD) with the light-front time $x^+ = x^0 + x^3$ as the evolution parameter is maximized in contrast to the usual instant form dynamics (IFD) with the ordinary time $x^0$ as the evolution parameter. In LFD, the individual $x^+$-ordered amplitudes contributing to $F(q^2)$ are invariant under the boost, i.e., frame-independent, while the individual $x^0$-ordered amplitudes in IFD are not invariant under the boost but dependent on the reference frame. The LFD allows to get the analytic result for the one-loop triangle diagram which covers not only the spacelike ($q^{2}<0$) but also timelike region ($q^{2}>0$). Using the analytic results, we verify that the real and imaginary parts of the form factor satisfy the dispersion relations in the entire $q^{2}$ space. Comparing with the results in $(3+1)$ dimensions, we discuss the transverse momentum effects on $F(q^2)$ . We also discuss the longitudinal charge density in terms of the boost invariant variable $\tilde z = p^+ x^-$ in LFD.
description: 15 pages, 12 figures; Slight changes have been made in the title and abstract. Version to appear in Phys. Rev. D
DOCUMENTATION AND SIGNIFICANCE OF TECTONIC EVENTS IN THE NORTHERN TABAS BLOCK (EAST-CENTRAL IRAN) DURING THE MIDDLE AND LATE JURASSIC
Creators: name: SEYED-EMAMI, KAZEM
name: T. FÜRSICH, FRANZ
name: WILMSEN, MARKUS
Publisher: name: Università degli Studi di Milano
Year: 2004

description: Apart from global sea-level fluctuations, the sedimentary pattern of the northern Tabas Block during the Middle and Late Jurassic was mainly governed by tectonic events of varying intensity and areal extent. These events took place during the Middle Bajocian (mid-Cimmerian tectonic phase), Early Bathonian, Late Bathonian, Early Callovian, Late Oxfordian, and Late Kimmeridgian. The importance and extent of each event and its influence on the facies pattern of the northern Tabas Block is briefly discussed and demostrated by some examples.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 110, No 1
HMG -- Homogeneous multigrid for HDG
Creators: name: Lu, Peipei
name: Rupp, Andreas
name: Kanschat, Guido
Publisher: name: arXiv
Year: 2020
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65F10, 65N30, 65N50

description: We introduce a homogeneous multigrid method in the sense that it uses the same HDG discretization scheme for Poisson's equation on all levels. In particular, we construct a stable injection operator and prove optimal convergence of the method under the assumption of elliptic regularity. Numerical experiments underline our analytical findings.
Electronic polarons in an extended Falicov-Kimball model
Creators: name: Brydon, P. M. R.
name: Gulacsi, M.
name: Bishop, A. R.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We examine the one-dimensional spinless Falicov-Kimball model extended by a hybridization potential between the localized and itinerant electron states. Below half-filling we find a crossover from a mixed-valence metal to an integer-valence phase separated state with increasing on-site Coulomb repulsion. This crossover regime is characterized by local competition between the strong- and weak-coupling behaviour, manifested by the formation of an electronic polaron liquid. We identify this intermediate-coupling regime as a charge-analogy of the Griffiths phase; a phase diagram is presented and discussed in detail.
description: RevTex, 10 pages, 1 figure; revised discussion
The widest broadband transmission spectrum (0.38-1.71 $μ$m) of HD 189733b from ground-based chromatic Rossiter-McLaughlin observations
Creators: name: Oshagh, M.
name: Bauer, F. F.
name: Lafarga, M.
name: Molaverdikhani, K.
name: Amado, P. J.
name: Nortmann, L.
name: Reiners, A.
name: Guzmán-Mesa, A.
name: Pallé, E.
name: Nagel, E.
name: Caballero, J. A.
name: Casasayas-Barris, N.
name: Claret, A.
name: Czesla, S.
name: Galadí, D.
name: Henning, Th.
name: Khalafinejad, S.
name: López-Puertas, M.
name: Montes, D.
name: Quirrenbach, A.
name: Ribas, I.
name: Stangret, M.
name: Yan, F.
name: Osorio, M. R. Zapatero
name: Zechmeister, M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Multiband photometric transit observations (spectro-photometric) have been used mostly so far to retrieve broadband transmission spectra of transiting exoplanets in order to study their atmospheres. An alternative method was proposed, and has only been used once, to recover broadband transmission spectra using chromatic Rossiter-McLaughlin observations. We use the chromatic Rossiter-McLaughlin technique on archival and new observational data obtained with the HARPS and CARMENES instruments to retrieve transmission spectra of HD 189733b. The combined results cover the widest retrieved broadband transmission spectrum of an exoplanet obtained from ground-based observation. Our retrieved spectrum in the visible wavelength range shows the signature of a hazy atmosphere, and also includes an indication for the presence of sodium and potassium. These findings all agree with previous studies. The combined visible and near-infrared transmission spectrum exhibits a strong steep slope that may have several origins, such as a super-Rayleigh slope in the atmosphere of HD 189733b, an unknown systematic instrumental offset between the visible and near-infrared, or a strong stellar activity contamination. The host star is indeed known to be very active and might easily generate spurious features in the retrieved transmission spectra. Using our CARMENES observations, we assessed this scenario and place an informative constraint on some properties of the active regions of HD 189733. We demonstrate that the presence of starspots on HD 189733 can easily explain our observed strong slope in the broadband transmission spectrum.
description: 10 pages, 8 figures, 4 tables, accepted for publication in A&A
Approximation Algorithms for the Discrete Time-Cost Tradeoff Problem
Creators: name: Skutella, Martin
Publisher: name: Technische Universität Berlin
Year: 1996
Subjects: subject: 510 Mathematik
subject: time-cost tradeoff
subject: approximation algorithm
subject: scheduling
subject: bicriteria optimization
subject: budget

description: Due to its obvious practical relevance, the Time-Cost Tradeoff Problem has achieved the attention of many researchers over the last thirty years. Within this context, we consider projects given by a set of single activities and precedence constraints on these activities. The duration of each activity is variable. However, the shorter the chosen duration is, the higher is the cost caused by executing the activity. This defines the proper time-cost tradeoff}: short project durations correspond to high cost and vice versa.
Group theory on quantum Boltzmann machine
Creators: name: Song, Hai-jing
name: Zhou, D. L.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Group theory is extremely successful in characterizing the symmetries in quantum systems, which greatly simplifies and unifies our treatments of quantum systems. Here we introduce the concept of the symmetry for a quantum Boltzmann machine and develop a group theory to describe the symmetry. This symmetry implies not only that all the target states related with the symmetry transformations are equivalent, but also that for a given target state all the optimal solutions related with the symmetry transformations that keeps the target state invariant are equivalent. For the Boltzmann machines built on qubits, we propose a systematic procedure to construct the group, and develop a numerical algorithm to verify the completeness of our construction.
Narratives of young children with language impairment: form versus content
Creators: name: Oxelgren, Corinne Marilyn
Publisher: name: University of British Columbia
Year: 2009

description: It has been proposed that narratives reflect a diverse knowledge base. In the narratives produced by children with normally developing language, it is difficult to tease apart the various knowledge domains. However, for children with specific language impairment (SLI), there is asynchrony in the development of at least two knowledge domains, event knowledge and linguistic knowledge. This asynchrony makes it easier to separately examine these knowledge domains within the narrative context. Narrative event knowledge was the focus of this thesis. In particular, two studies were conducted to examine the narrative content structure abilities of younger children with SLI. In Study One, 10 children with SLI, ranging in age from 4-6 years, were language-matched with 10 normal-language (NL) children, ranging in age from 2-4 years. Two sets of line-drawn picture cards were used to elicit two separate narratives. A developmental narrative stages scheme, based on Trabasso, Stein, Rodkin, Munger and Baughn's (1992) research, was devised to score the data. It was hypothesized that children with SLI would produce narrative content structure in advance of their NL counterparts, given their age advantage and likely accompanying advantage in world experience and cognitive development. Data from the group with a lower language level supported the hypothesis. No strong trends were apparent for the group with a higher language level. Study Two mental age (MA) -matched 8 children with SLI (mean MA, 68 months) with 8 NL children (mean MA, 72 months). It was hypothesized that matching by mental age would hold cognitive abilities constant so therefore the two groups would produce equivalent narrative content structure. Overall findings in Study Two supported the hypothesis. However, data from the higher MA-matched group indicated a trend in which children with SLI produced less advanced narrative content structure than their NL counterparts. The two studies, taken together, suggest that as children develop, language experience plays an increasingly significant role in narrative content production.
title: Income Misperception and Populism
Creators: name: Albers, Thilo Nils Hendrik
name: Kersting, Felix
name: Kosse, Fabian
Publisher: name: Universitätsbibliothek der Ludwig-Maximilians-Universität München
Year: 2022

description: We propose that false beliefs about the own current economic status are an important factor for explaining populist attitudes. Along with the subjects' receptiveness to right-wing populism, we elicit their perceived relative income positions in a representative survey of German households. We find that people with pessimistic beliefs about their income position are more attuned to populist statements. Key to understanding the misperception-populism relationship are strong gender differences in the mechanism: Misperception triggers income dissatisfaction for both men and women, but the former are much more likely to channel their discontent into affection for populist ideas.
Baxter Q-operator for graded SL(2|1) spin chain
Creators: name: Belitsky, A. V.
name: Derkachov, S. E.
name: Korchemsky, G. P.
name: Manashov, A. N.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study an integrable noncompact superspin chain model that emerged in recent studies of the dilatation operator in the N=1 super-Yang-Mills theory. It was found that the latter can be mapped into a homogeneous Heisenberg magnet with the quantum space in all sites corresponding to infinite-dimensional representations of the SL(2|1) group. We extend the method of the Baxter Q-operator to spin chains with supergroup symmetry and apply it to determine the eigenspectrum of the model. Our analysis relies on a factorization property of the R-operators acting on the tensor product of two generic infinite-dimensional SL(2|1) representations. It allows us to factorize an arbitrary transfer matrix into a product of three `elementary' transfer matrices which we identify as Baxter Q-operators. We establish functional relations between transfer matrices and use them to derive the TQ-relations for the Q-operators. The proposed construction can be generalized to integrable models based on supergroups of higher rank and, in distinction to the Bethe Ansatz, it is not sensitive to the existence of the pseudovacuum state in the quantum space of the model.
description: 62 pages, 9 figures
Reducing the hydrogen content in liquid helium
Creators: name: Sifrig, Dominik
name: Martin, Sascha
name: Zumbühl, Dominik
name: Schönenberger, Christian
name: Marot, Laurent
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: Helium has the lowest boiling point of any element in nature at normal atmospheric pressure. Therefore, any unwanted substance like impurities present in liquid helium will be frozen and will be in solid form. Even if these solid impurities can be easily eliminated by filtering, liquid helium may contain a non-negligible quantity of molecular hydrogen. These traces of molecular hydrogen are the causes of a known problem worldwide: the blocking of fine-capillary tubes used as flow impedances in helium evaporation cryostats to achieve temperatures below 4,2K. This problem seriously affects a wide range of cryogenic equipment used in low-temperature physics research and leads to a dramatic loss of time and costs due to the high price of helium. Here, we present first the measurement of molecular hydrogen content in helium gas. Three measures to decrease this molecular hydrogen are afterward proposed; (i) improving the helium quality, (ii) release of helium gas in the atmosphere during purge time for the regeneration cycle of the helium liquefier's internal purifier, and (iii) installation of two catalytic converters in a closed helium circuit. These actions have eliminated our low-temperature impedance blockage occurrences now for more than two years.
Analysis of the SQP-method for optimal control problems governed by the instationary Navier-Stokes equations based on Lp-theory
Creators: name: Wachsmuth, Daniel
Publisher: name: Technische Universität Berlin
Year: 2004
Subjects: subject: 510 Mathematik
subject: optimal control
subject: Navier-Stokes equations
subject: control constraints
subject: Lipschitz stability
subject: SQP-method

description: The aim of this article is to present a convergence theory of the SQP-method applied to optimal control problems for the instationary Navier-Stokes equations. We will employ a second-order sufficient optimality condition, which requires that the second derivative of the Lagrangian is positive definit on a subspace of inactive constraints. Therefore, we have to use $L^p$-theory of optimal controls of the instationary Navier-Stokes equations rather than Hilbert space methods. We prove local convergence of the SQP-method. This behaviour is confirmed by numerical tests.
Re-transcription of texts told by Stella Jarnaghan
Creators: name: Parker, Verdena
name: Spence, Justin
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2021
Subjects: subject: hup

description: Audio files VP-190919-04 and VP-190919-05: Re-transcription and translation of texts told by Stella Jarnaghan to Mary Woodward in 1953, archived at the Survey of California and Other Indian Languages (Woodward.002.001), Text 15, p. 40 (VP-190919-04) and Text 16, p. 41 (VP-190919-05).
Unital Banach algebras not isomorphic to Calkin algebras of separable Banach spaces
Creators: name: Horváth, Bence
name: Kania, Tomasz
Publisher: name: arXiv
Year: 2021
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 47L10 (primary), 46B03 (secondary)

description: Recent developments in Banach space theory provided unexpected examples of unital Banach algebras that are isomorphic to Calkin algebras of Banach spaces, however no example of a unital Banach algebra that cannot be realised as a~Calkin algebra has been found so far. This naturally led to the question of possible limitations of such assignments. In the present note we provide examples of unital Banach algebras meeting the necessary density condition for being the Calkin algebra of a separable Banach space that are not isomorphic to Calkin algebras of such spaces, nonetheless. The examples may be found of the form $C(X)$ for a compact space $X$, $\ell_1(G)$ for some torsion-free Abelian group, and a~simple, unital AF $C^*$-algebra. Extensions to higher densities are also presented.
description: 7 pp, to appear in Proceedings of the American Mathematical Society
Quantitative bispectra from multifield inflation
Creators: name: Rigopoulos, G. I.
name: Shellard, E. P. S.
name: van Tent, B. J. W.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: After simplifying and improving the non-Gaussian formalism we developed in previous work, we derive a quantitative expression for the three-point correlator (bispectrum) of the curvature perturbation in general multiple-field inflation models. Our result describes the evolution of non-Gaussianity on superhorizon scales caused by the nonlinear influence of isocurvature perturbations on the adiabatic perturbation during inflation. We then study a simple quadratic two-field potential and find that when slow roll breaks down and the field trajectory changes direction in field space, the non-Gaussianity can become large. However, for the simple models studied to date, the magnitude of this non-Gaussianity decays away after the isocurvature mode is converted into the adiabatic mode.
description: 7 pages, 1 figure. v4: Added remarks on momentum dependence, minor textual changes, matches published version
A memristive model for graphene emitters: hysteresis and self-crossing
Creators: name: Gorodetskiy, D. V.
name: Shevchenko, S. N.
name: Gusel'nikov, A. V.
name: Okotrub, A. V.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Hysteresis exhibited by current-voltage characteristics during field-emission experiments is often considered undesirable in terms of practical applications. However, this is an appealing effect for the purposes of memristive devices. We developed a two-stage model to describe hysteretic characteristics, with a particular focus on the system which includes a cathode made of a single-layered graphene sheet on a substrate. In addition to hysteresis, the current-voltage curves display also an unusual self-crossing behavior. The presented memristive model can be used for quantitative descriptions of different hysteretic characteristics such as abrupt changes and self-crossings and for understanding (and modeling) the processes associated with field emission from plane graphene emitters.
On total reality of meromorphic functions
Creators: name: Degtyarev, A.
name: Ekedahl, T.
name: Itenberg, I.
name: Shapiro, B.
name: Shapiro, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14P05; 14P25

description: We show that if a meromorphic function of degree at most four on a real algebraic curve of an arbitrary genus has only real critical points then it is conjugate to a real meromorphic function after a suitable projective automorphism of the image.
description: 13 pages
MIDDLE TO LATE JURASSIC BIOFACIES OF SAUDI ARABIA
Creators: name: W. HUGHES, GERAINT
Publisher: name: Università degli Studi di Milano
Year: 2004

description: Saudi Arabian Jurassic carbonate hydrocarbon reservoirs were first examined stratigraphically using microfauna. Current microfaunal studies concentrate on the identification and constraint of palaeoenvironmental variations and determination of high-resolution depositional cyclicity of the reservoir carbonates. It is apparent that the environmental sensitivity of benthonic foraminifera provides a potentially valuable technique for the determining subtle variations in the depositional environment and also providing a proxy for sea-level fluctuations.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 110, No 1
ENVIRONMENTS AND FAUNAL PATTERNS IN THE KACHCHH RIFT BASIN, WESTERN INDIA, DURING THE JURASSIC
Creators: name: THEODOR FÜRSICH, FRANZ
name: H. CALLOMON, JOHN
name: K. PANDEY, DHIRENDRA
name: K. JAITLY, ANAND
Publisher: name: Università degli Studi di Milano
Year: 2004

description: Marine Jurassic sediments (Bajocian-Tithonian) of the Kachchh Basin were deposited in a ramp setting. Except during the Middle and Late Bathonian, when a carbonate regime became established, the fill of the basin consists predominantly of siliciclastics. The sediments represent environments that range from coastal plains (rivers and associated flood plains with caliche nodules), deltas, brackish water lagoons, nearshore sand and iron-oolite bars of the inner ramp, generally situated above fair-weather wave-base, to the middle ramp influenced by storm-waves and by storm-generated currents, and finally to the outer ramp which is characterised by low energy, fine-grained sediments. Changes in relative sea level produced a cyclic sedimentation pattern. The rich benthic fauna of macroinvertebrates is dominated by bivalves, followed by brachiopods, gastropods, corals, serpulids, and sponges. The analysis of 370 statistical samples and more than 27, 000 specimens produced more than 40 benthic associations and assemblages. They show a relationship to several environmental parameters, two of which, salinity and climate, are briefly discussed. The spatial distribution of the facies and biota is outlined for two time slices, the Bathonian and the Callovian-Oxfordian, respectively.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 110, No 1
Regularity and Stability of optimal controls of instationary Navier-Stokes equations
Creators: name: Wachsmuth, Daniel
Publisher: name: Technische Universität Berlin
Year: 2004
Subjects: subject: 510 Mathematik
subject: optimal control
subject: Navier-Stokes equations
subject: control constraints
subject: Lipschitz stability
subject: regularity

description: The regularity and stability of optimal controls of instationary Navier-Stokes equations is investigated. Under suitable assumptions every control satisfying first-order necessary conditions is shown to be a continuous function in both space and time. Moreover, the behaviour of a locally optimal control under certain perturbations of the cost functional and the state equation is investigated. Lipschitz stability is proven provided a second-order sufficient optimality condition holds.
New Results on the Ages of Star Clusters in Region B of M82
Creators: name: Konstantopoulos, I. S.
name: Bastian, N.
name: Smith, L. J.
name: Trancho, G.
name: Westmoquette, M. S.
name: Gallagher, J. S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The post-starburst region B in M82 and its massive star cluster component have been the focus of multiple studies, with reports that there is a large population of coeval clusters of age ~1 Gyr, which were created with a Gaussian initial mass distribution. This is in disagreement with other studies of young star clusters, which invariably find a featureless power-law mass distribution. Here, we present Gemini-North optical spectra of seven star clusters in M82-B and show that their ages are all between 10 and 300 Myr (a factor of 3-100 younger than previous photometric results) and that their extinctions range between near-zero and 4 mag (Av). Using new HST ACS-HRC U-band observations we age date an additional ~30 clusters whose ages/extinctions agree well with those determined from spectroscopy. Completeness tests show that the reported `turn-over' in the luminosity/mass distributions is most likely an artefact, due to the resolved nature of the clusters. We also show that the radial velocities of the clusters are inconsistent with them belonging to a bound region.
description: To appear in Perez, de Grijs and Gonzalez Delgado (eds.), `Young Massive Star Clusters: Initial Conditions and Environments', 2008, Astrophysics & Space Science
THE STRATIGRAPHY OF THE UPPER BATHONIAN TO MIDDLE OXFORDIAN SUCESSION OF THE ARAGONESE BRANCH OF THE CORDILLERA IBÉRICA (SPAIN) AND ITS EUROPEAN CONTEXT
Creators: name: N. PAGE, KEVIN
name: BELLO, JULIA
name: DOLORES LARDIÉS, MARÍA
name: MELÉNDEZ, GUILLERMO
name: RAMAJO, JAVIER
name: ZIANI, HASSAN
Publisher: name: Università degli Studi di Milano
Year: 2004

description: The Upper Bathonian-Middle Oxfordian succession of the Aragonese branch of the Cordillera Ibérica is one of the most completely developed in Europe and includes localities of international importance for Jurassic bio- and chronostratigraphy. Of particular importance are a potential stratotype for the Upper Bathonian of North West Europe and reference sections for a number of Submediterranean Province Middle Oxfordian biostratigraphic units. The intervening Callovian sequence, albeit locally strongly condensed, also includes faunas of key stratigraphical importance. The sequence of stratigraphically important ammonite faunas for this interval is here reviewed and placed in its European context.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 110, No 1
THE CALLOVIAN-OXFORDIAN BOUNDARY IN BRITAIN: A REVIEW OF KEY SECTIONS AND THEIR CORRELATION WITH THE PROPOSED GLOBAL STRATOTYPE SECTION AND POINT FOR THE OXFORDIAN IN HAUTE PROVENCE, FRANCE
Creators: name: N. PAGE, KEVIN
Publisher: name: Università degli Studi di Milano
Year: 2004

description: The historical type area of the Oxfordian Stage and its lowest subchronozone (Scarburgense Subchronozone of the Mariae Chronozone) are in Great Britain, in southern central (Oxford) and north eastern England (Scarborough), respectively. In neither district, however, are sequences sufficient complete to satisfy ICS requirements for a GSSP. Subsequent work in Haute Provence, south east France, however, has revealed considerably expanded sequences in Terre Noire facies which satisfy most ICS criteria and a GSSP for the Oxfordian Stage has now been formally proposed in this region. One British section, however, on the Dorset coast near Weymouth (Ham Cliff/ Redcliff Point), is relatively expanded and has the potential to complement the French candidate GSSP by yielding additional information on microfossil assemblages (e.g. ostrocods, foraminifera, coccoliths and holothurians). The sequence of ammonite faunas across the stage boundary at this and other key UK localities is reviewed, synthesised and correlated with the candidate GSSP in Haute Provence. This correlation can provide a framework within which additional information derived from UK sites, for instance from microfossil or geochemical studies, can be integrated to assist global correlation of the base of the Oxfordian Stage.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 110, No 1
Nonlinear Transport in One-Dimensional Mott Insulator in Strong Electric Fields
Creators: name: Oka, Takashi
name: Arita, Ryotaro
name: Aoki, Hideo
Publisher: name: arXiv
Year: 2005
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Time-dependent Schroedinger's equation is integrated for a one-dimensional strongly-correlated electron system driven by large electric fields. For larger electric fields, many-body Landau-Zener tunneling takes place at anti-crossings of the many-body energy levels. The nonlinear $I$-$V$ characteristics as well as the time dependence of the energy expectation value are obtained. The energy of the Mott insulator in electric fields shows a saturation, which suggests a dynamical localization in energy space of many-body wave functions.
description: 3 pages, 3 figures, Proceedings of SCES'04 (Karlsruhe)
On optimal control problems with convex control constraints
Creators: name: Wachsmuth, Daniel
Publisher: name: Technische Universität Berlin
Year: 2005
Subjects: subject: 510 Mathematik
subject: optimal control
subject: convex control constraints
subject: set-valued mappings
subject: active-set strategy
subject: Navier-Stokes equations

description: We investigate optimal control problems with vector-valued controls. As model problem serve the optimal distributed control of the instationary Navier-Stokes equations. We study pointwise convex control constraints, which is a constraint of the form u(x,t)?U(x,t) that has to hold on the domain Q. Here, U is an set-valued mapping that is assumed to be measurable with convex and closed images. We establish first-order necessary as well as second-order sufficient optimality conditions. And we prove regularity results for locally optimal controls.
Nonlinear Compression of Besselon Waves for High Repetition-Rate Subpicosecond Pulses Trains
Creators: name: Sheveleva, Anastasiia
name: Finot, Christophe
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We theoretically and experimentally demonstrate the generation of high-quality low duty-cycle pulse trains at repetition rates of 28 GHz, 56 GHz and 112 GHz. Starting from a continuous wave we benefit from phase modulations in the temporal and spectral domains by applying a sinusoidal profile and a set of well-chosen $π$ shifts, respectively, to generate a train of modified besselons at doubled repetition rate. With further nonlinear spectral expansion in a normally dispersive fiber followed by dispersion compensation we achieve subpicosecond durations and a duty cycle as low as 0.025 at 28 GHz. Spectral cancelation of one component over two or four enables to further double or quadruple the repetition rate.
Numerical solution of optimal control problems with convex control constraints
Creators: name: Wachsmuth, Daniel
Publisher: name: Technische Universität Berlin
Year: 2005
Subjects: subject: 510 Mathematik
subject: optimal control
subject: convex control constraints
subject: set-valued mappings
subject: active-set strategy
subject: Navier-Stokes equations

description: We study optimal control problems with vector-valued controls. As model problem serves the optimal distributed control of the instationary Navier-Stokes equations. In the article, we propose a solution strategy to solve optimal control problems with pointwise convex control constraints. It involves a SQP-like step with an imbedded active-set algorithm. The efficiency of that method is demonstrated in numerical examples and compared to the primal-dual active-set strategy for box-constraints.
Direct evidence for magnetic reconnection at the boundaries of magnetic switchbacks with Parker Solar Probe
Creators: name: Froment, C.
name: Krasnoselskikh, V.
name: de Wit, T. Dudok
name: Agapitov, O.
name: Fargette, N.
name: Lavraud, B.
name: Larosa, A.
name: Kretzschmar, M.
name: Jagarlamudi, V. K.
name: Velli, M.
name: Malaspina, D.
name: Whittlesey, P. L.
name: Bale, S. D.
name: Case, A. W.
name: Goetz, K.
name: Kasper, J. C.
name: Korreck, K. E.
name: Larson, D. E.
name: MacDowall, R. J.
name: Mozer, F. S.
name: Pulupa, M.
name: Revillet, C.
name: Stevens, M. L.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: Parker Solar Probe's first encounters with the Sun revealed the presence of ubiquitous localised magnetic deflections in the inner heliosphere; these structures, often called switchbacks, are particularly striking in solar wind streams originating from coronal holes. We report the direct evidence for magnetic reconnection occuring at the boundaries of three switchbacks crossed by Parker Solar Probe (PSP) at a distance of 45 to 48 solar radii of the Sun during its first encounter. We analyse the magnetic field and plasma parameters from the FIELDS and SWEAP instruments. The three structures analysed all show typical signatures of magnetic reconnection. The ion velocity and magnetic field are first correlated and then anti-correlated at the inbound and outbound edges of the bifurcated current sheets with a central ion flow jet. Most of the reconnection events have a strong guide field and moderate magnetic shear but one current sheet shows indications of quasi anti-parallel reconnection in conjunction with a magnetic field magnitude decrease by $90\%$. Given the wealth of intense current sheets observed by PSP, reconnection at switchbacks boundaries appears to be rare. However, as the switchback boundaries accomodate currents one can conjecture that the geometry of these boundaries offers favourable conditions for magnetic reconnection to occur. Such a mechanism would thus contribute in reconfiguring the magnetic field of the switchbacks, affecting the dynamics of the solar wind and eventually contributing to the blending of the structures with the regular wind as they propagate away from the Sun.
description: 11 pages, 7 figures, 2 tables, accepted for publication in A&A, PSP special issue (v2: typos correction)