cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
On Strongly Coupled Matrix Theory and Stochastic Quantization: A New Approach to Holographic Dualities
Creators: name: Heller, Nick
name: Sahakian, Vatche
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Stochastic quantization provides an alternate approach to the computation of quantum observables, by stochastically sampling phase space in a path integral. Furthermore, the stochastic variational method can provide analytical control over the strong coupling regime of a quantum field theory -- provided one has a decent qualitative guess at the form of certain observables at strong coupling. In the context of the holographic duality, the strong coupling regime of a Yang-Mills theory can capture gravitational dynamics. This can provide enough insight to guide a stochastic variational ansatz. We demonstrate this in the bosonic Banks-Fischler-Shenker-Susskind Matrix theory. We compute a two-point function at all values of coupling using the variational method showing agreement with lattice numerical computations and capturing the confinement-deconfinement phase transition at strong coupling. This opens up a new realm of possibilities for exploring the holographic duality and emergent geometry.
description: 24 pages, 5 figures; v2: added citations
Directed evolution of glycolytic enzymes : glyceraldehyde-3-phosphate dehydrogenases
Creators: name: Wanty, Christopher James
Publisher: name: The Australian National University
Year: 2018
Subjects: subject: QP603.D4 W36 2010
subject: Enzymes Biotechnology
subject: Glycolysis
subject: Dehydrogenases

description: Glyceraldehyde-3-phosphate dehydrogenase (Gapdh) performs a vital step in glycolysis. An in vitro fermentative system is being developed to convert glucose to ethanol. The system is not cofactor neutral, so will eventually stall through production of adenosine triphosphate (ATP). The Gapdh catalysed step can be modified by use of a non-phosphorylating variant (GapN) of the enzyme. GapN catalyses the Gapdh oxidation and the next step of the pathway without the production of ATP through incorporation of phosphate that normally occurs. This results in the pathway producing ethanol and carbon dioxide from glucose, with complete cofactor recycling. This also gives an overall thermodynamic advantage to the pathway. A GapN enzyme from the thermophile Thermoproteus tenax was examined for suitability to this role, and was modified to increase activity under mesophilic conditions through application of directed evolution techniques. Methods for evolving this enzyme were developed and are described. Two mutants from the evolution are characterised. Both possess a threefold enhanced activity at 30{u00B0}C and one and a half to tenfold improvement at 50{u00B0}C. One suggests a change in optimal active temperature, while the other has improved activity under all conditions tested. The first heat activation of GapN was observed in both the wild type and the mutants, with a sevenfold improvement in wild-type activity and a fourfold and modest improvement in the mutants. This phenomenon is not commonly reported outside of heat-response proteins. Alternative screening methods were investigated for the evolution. Primarily an E. coli strain lacking the gene gapA, that encodes Gapdh, was to be used for screening. There were significant difficulties knocking out gapA that are now believed to be caused by non-glycolytic roles of Gapdh in the cell. A second evolution was performed with a mutant of the E. coli Gapdh possessing a cysteine 149 to alanine mutation. This mutation causes a GapN like activity in Gapdh, though it is understood to occur by a different mechanism and to use a different isomer of the substrate for activity. Following two rounds of evolution an enzyme with a wild-type cysteine at position 149 was selected. This suggests potential problems with the C149A mutant as an evolution target. A third Gapdh variant from Zymomonas mobilis was investigated for possible use in the pathway, or as a possible target for evolution. This variant has not been previously characterised. The first kinetic characterisation and crystal structures are reported. The enzyme is kinetically interesting for its strong substrate binding of all substrates with Km at low micromolar ranges and a turnover of 16 s-1 that could be attributed to the environment of Z. mobilis. The best crystallographic data collected have given a structural solution to 3.6 A.
Cosmology without Einstein's assumption that inertial mass produces gravity
Creators: name: Ellis, Homer G.
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Giving up Einstein's assumption, implicit in his 1916 field equations, that inertial mass, even in its appearance as energy, is equivalent to active gravitational mass and therefore is a source of gravity allows revising the field equations to a form in which a positive cosmological constant is seen to (mis)represent a uniform negative net mass density of gravitationally attractive and gravitationally repulsive matter. Field equations with both positive and negative active gravitational mass densities of both primordial and continuously created matter incorporated, along with two scalar fields to `relax the constraints' on the space-time geometry, yield cosmological solutions that exhibit inflation, deceleration, coasting, acceleration, and a `big bounce' instead of a `big bang', and provide good fits to a Hubble diagram of type Ia supernovae data. The repulsive matter is identified as the back sides of the `drainholes' introduced by the author in 1973 as solutions of those same field equations. Drainholes (prototypical examples of `traversable wormholes') are topological tunnels in space which gravitationally attract on their front, entrance sides and repel more strongly on their back, exit sides. The front sides serve both as the gravitating cores of the visible, baryonic particles of primordial matter and as the continuously created, invisible particles of the `dark matter' needed to hold together the large scale structures seen in the universe; the back sides serve as the misnamed `dark energy' driving the current acceleration of the expansion of the universe. Formation of cosmic voids, walls, filaments, and nodes is attributed to expulsion of drainhole entrances from regions populated by drainhole exits, and accumulation of the entrances on boundaries separating those regions.
description: v4: Essential revision and major extension, new title; v5: introduction, two references, and table of contents added; v6: further discussion of issues, improved fitting of model to SNe Ia data marginally favors closed universe aged 12.52 Gyr; v7: 35 pages, improved clarity, new material and references; v8: much abbreviated version of v7, 26 pages, new title (see v7 for Hubble calculations)
The impurity problem, non-linear transport, and dynamics in quantum electronic systems without translational symmetry
Creators: name: Wu, Angkun
Publisher: name: No Publisher Supplied
Year: 2023

description: Quantum electronic systems are important for technological innovation and scientific progress. Exploring entanglement and strong correlation in quantum systems can also lead to novel materials and contribute to quantum computing. The focus of this thesis is on quantum electronic systems that lack translational symmetry, where we investigate strong correlation effects due to incommensurate potential, non-linear optical response in disordered systems, and the dynamics of an integrable time-dependent superconductivity model with all-to-all interaction.Motivated by non-Fermi-liquid (NFL) behavior in heavy-fermion quasicrystals, the strong correlation among electrons in quasicrystals is investigated. The single impurity problem in a one-dimensional quasicrystal is studied. Analyzing the fractal X-ray edge problem, the emergence of bands and gaps in the 1-D quasicrystal is scrutinized as well as the Anderson single impurity problem non-perturbatively using the numerical renormalization group.The density matrix renormalization group (DMRG) and tensor network representation of quantum many-body states provide an alternative approach to the impurity problem. By developing a fermionic Gaussian circuit, which improves the DMRG sweeping rate and yields physically interpretable orbitals reflecting the Kondo screening length, we achieve entanglement renormalization on bath electrons as well as observe emergent behavior in coarse-grained models.Disorder in the topological materials–Weyl semimetals, and how it can change physical observables dramatically is investigated. In clean chiral Weyl semimetals, the quantized circular photogalvanic effect (CPGE) is hard to observe in experiments, and the momentum lifetime of photexcited carriers must be taken into consideration. In this thesis, experimental results are analyzed from the perspective of potential disorder.Quantum many-body systems beyond thermal equilibrium are another intriguing topic and are explored through a specific time-dependent BCS superconducting model. The dynamics of a quantum state is examined, and integrability is disrupted through various methods. It is discovered that the mean-field theory is precisely accurate in the thermodynamic limit and the system is resilient to small random disorder. Overall, this thesis contributes to the understanding of strong correlation effects in quantum electronic systems lacking translational symmetry. From investigating single impurity problems, disorder in chiral Weyl semimetals, and quantum many-body systems beyond thermal equilibrium, novel insights are gained into the behavior of quantum electronic systems with important implications for technological innovation and scientific progress.
Correlated Oxide Dirac Semimetal in the Extreme Quantum Limit
Creators: name: Ok, Jong Mok
name: Mohanta, Narayan
name: Zhang, Jie
name: Yoon, Sangmoon
name: Okamoto, Satoshi
name: Choi, Eun Sang
name: Zhou, Hua
name: Briggeman, Megan
name: Irvin, Patrick
name: Lupini, Andrew R.
name: Pai, Yun-Yi
name: Skoropata, Elizabeth
name: Sohn, Changhee
name: Li, Haoxiang
name: Miao, Hu
name: Lawrie, Benjamin
name: Choi, Woo Seok
name: Eres, Gyula
name: Levy, Jeremy
name: Lee, Ho Nyung
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Quantum materials (QMs) with strong correlation and non-trivial topology are indispensable to next-generation information and computing technologies. Exploitation of topological band structure is an ideal starting point to realize correlated topological QMs. Herein, we report that strain-induced symmetry modification in correlated oxide SrNbO3 thin films creates an emerging topological band structure. Dirac electrons in strained SrNbO3 films reveal ultra-high mobility (100,000 cm2/Vs), exceptionally small effective mass (0.04me), and non-zero Berry phase. More importantly, strained SrNbO3 films reach the extreme quantum limit, exhibiting a sign of fractional occupation of Landau levels and giant mass enhancement. Our results suggest that symmetry-modified SrNbO3 is a rare example of a correlated topological QM, in which strong correlation of Dirac electrons leads to the realization of fractional occupation of Landau levels.
description: accepted in Sci. Adv
Hansenocaris undetermined
Creators: name: Olesen, Jørgen
name: Grygier, Mark J.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Hansenocarididae
Hansenocaris
Hansenocaris undetermined

description: Y-nauplius Type G
Figs 2, 8E–G
Type G – Dreyer et al. 2023a: figs 3, 5a, c, tables s1–s2.
Material examined
JAPAN – Okinawa, Sesoko I., laboratory pier, 26°38ʹ09.4ʺ N, 127°51ʹ55.2ʺ E • 3 LSN; 1991–2005 • 21 LSN, 6 of which molted to cyprids; 2018–2019 (Tables 1 and S1).
Description
LAST-STAGE NAUPLIUS (LSN). Lecithotrophic. Body widely ovate in dorso-ventral view; about 1.2 times as long as wide; lateral margins tapering gradually towards caudal end with no marked discontinuity at posterior end of cephalic shield. In lateral view trunk axis downturned a full 90° relative to cephalic axis, with furcal spines directed anteriorly from end of trunk (i.e., anatomically ventrally but parallel to cephalic axis). Body length ca 300–320 µm (following body curvature in lateral view) (without dorso-caudal spine), greatest width 220 µm, greatest dorso-ventral thickness ca 100 µm. Labrum elevated, trapezoidal, about as long as wide with distinct posterior margin and with surface divided into facets by cuticular ridges; pore pattern not examined. Caudal end rounded, terminating in very short (8 µm), conical dorso-caudal spine and pair of long (40 µm), distally curved, talon-like furcal spines with pair of double-spines at (anatomically) dorsal base of each.
CYPRID VIEWED THROUGH CUTICLE OF LSN. Body weakly brown-pigmented. Many lipid vesicles present in dorsal part of cephalon, and, in some specimens, a dense concentration of yolk granules in central gut-like tube. Lateral margins of cephalic region with clusters of crystalline-like particles.
Identification and variation
Easily recognizable by the combination of its right-angle bend of the body, the large, talon-like furcal spines (‘medium talon’ in comparison to the most similar morphospecies, Types F and H), accompanied by small, basal double-spines, and the lateral clumps of crystalline particles within the margins of the cephalic shield (possibly remnant from the LSN).
Distribution
Japan (Sesoko Island, Okinawa).
description: Published as part of Olesen, Jørgen & Grygier, Mark J., 2024, Taxonomic diversity of marine planktonic ' y-larvae' (Crustacea: Facetotecta) from a coral reef hotspot locality (Japan, Okinawa), with a key to y-nauplii, pp. 1-90 in European Journal of Taxonomy 929 (1) on page 23, DOI: 10.5852/ejt.2024.929.2479, http://zenodo.org/record/10876286
The Incidence of Dwarf Novae in Large Area Transient Searches
Creators: name: Rau, A.
name: Schwarz, R.
name: Kulkarni, S. R.
name: Ofek, E. O.
name: Kasliwal, M. M.
name: Brinkworth, C.
name: Cenko, S. B.
name: Lipkin, Y.
name: Soderberg, A. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Understanding and quantifying the contribution of known classes of transient and variable sources is an important lesson to be learned from the manifold of pre-cursors programs of the near-future large synoptic sky survey programs like SkyMapper, Pan-STARRS and LSST. With this goal in mind, we undertook photometric and spectroscopic follow-up observations of three recently reported unidentified transients. For two sources, WFI J132813.7-214237 and WFI J161953.3+031909, we show that unfortunate coincidences lead to their previous designation as transients. While the former is now interpreted as the spatial coincidence of a solar system object with faint background star, the latter is merely a cataclysmic variable unfortunately caught in and out of eclipse. The third candidate, ROTSE3 J160213.1-021311.7 is identified as an SU UMa-type dwarf novae with quiescent brightness of R~22.7 and an outburst amplitude of about 5 mag. The fourth event, SDSS-SN15207, similarly shows evidence for a dwarf nova origin. Our main conclusion is that cataclysmic variables in their various avata rs will contribute moderately to the population of transient objects.
description: ApJ in press
Deriving CME density from remote sensing data and comparison to in-situ measurements
Creators: name: Temmer, M.
name: Holzknecht, L.
name: Dumbovic, M.
name: Vrsnak, B.
name: Sachdeva, N.
name: Heinemann, S. G.
name: Dissauer, K.
name: Scolini, C.
name: Asvestari, E.
name: Veronig, A. M.
name: Hofmeister, S. J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We determine the 3D geometry and deprojected mass of 29 well-observed coronal mass ejections (CMEs) and their interplanetary counterparts (ICMEs) using combined STEREO-SOHO white-light data. From the geometry parameters we calculate the volume of the CME for the magnetic ejecta (flux-rope type geometry) and sheath structure (shell-like geometry resembling the (I)CME frontal rim). Working under the assumption that the CME mass is roughly equally distributed within a specific volume, we expand the CME self-similarly and calculate the CME density for distances close to the Sun (15-30 Rs) and at 1AU. Specific trends are derived comparing calculated and in-situ measured proton densities at 1AU, though large uncertainties are revealed due to the unknown mass and geometry evolution: i) a moderate correlation for the magnetic structure having a mass that stays rather constant (~0.56-0.59), and ii) a weak correlation for the sheath density (~0.26) by assuming the sheath region is an extra mass - as expected for a mass pile-up process - that is in its amount comparable to the initial CME deprojected mass. High correlations are derived between in-situ measured sheath density and the solar wind density (~ -0.73) and solar wind speed (~0.56) as measured 24 hours ahead of the arrival of the disturbance. This gives additional confirmation that the sheath-plasma indeed stems from piled-up solar wind material. While the CME interplanetary propagation speed is not related to the sheath density, the size of the CME may play some role in how much material could be piled up.
The development of face and object processing in childhood
Creators: name: Bennetts, Rachel
name: Murray, Ebony
name: Boyce, Tian
name: Bate, Sarah
Publisher: name: F1000Research
Year: 2015

description: There has been much debate over whether face and object recognition develop at a different rates during childhood. Some researchers suggest that face processing is not mature until the early teenage years, far later than object recognition; others suggest that face recognition is mature relatively early (by 5 yrs), and subsequent improvements reflect more general cognitive development. Recently, it has been suggested that both ideas are correct, but that face memory and face matching develop at different rates. This study addressed this hypothesis by examining face and object (bicycle) matching and memory in primary school children (5-11 yrs). In the memory test, children were asked to learn 4 or 6 faces and bikes; in the matching test, children completed a 3AFC simultaneous matching task. Both memory (N = 134) and matching (N = 432) showed significant improvements with age, but neither task showed an interaction between age and object – that is, memory and perception of faces showed a similar developmental trajectory to general object memory and perception. This suggests that both face memory and face matching are mature early in childhood (< 5yrs), and subsequent increases in performance are related to general cognitive development rather than face-specific processes.
A Quality Assessment Instrument for Systematic Literature Reviews in Software Engineering
Creators: name: Usman, Muhammad
name: Ali, Nauman bin
name: Wohlin, Claes
Publisher: name: arXiv
Year: 2021
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Context: Systematic literature reviews (SLRs) have become standard practise as part of software engineering research, although their quality varies. To build on the reviews, both for future research and industry practice, they need to be of high quality. Objective: To assess the quality of SLRs in software engineering, we put forward an appraisal instrument for SLRs. The instrument is intended for use by appraisers of reviews, but authors may also use it as a checklist when designing and documenting their reviews. Method: A well-established appraisal instrument from research in healthcare was used as a starting point to develop a quality assessment instrument. It is adapted to software engineering using guidelines, checklists, and experiences from software engineering. As a validation step, the first version was reviewed by four external experts on SLRs in software engineering and updated based on their feedback. Results: The outcome of the research is an appraisal instrument for the quality assessment of SLRs in software engineering. The instrument intends to support the appraiser in assessing the quality of an SLR. The instrument includes 16 items with different options to capture the quality. The item is assessed on a two or three-grade scale, depending on the item. The instrument also supports consolidating the items into groups, which are then used to assess the overall quality of a systematic literature review. Conclusion: It is concluded that the presented instrument may be helpful support for an appraiser in assessing the quality of SLRs in software engineering.
Ultra-rapid categorization of meaningful real-life scenes in people with and without ASD
Creators: name: Vanmarcke, Steven
name: Noens, Ilse
name: Steyaert, Jean
name: Wagemans, Johan
Publisher: name: F1000Research
Year: 2015

description: The Reverse Hierarchy Theory (RHT) by Hochstein and Ahissar (2002) assumes that ultra-rapid categorization of visual information (paradigm developed by Thorpe and colleagues, 1996) involves the extraction of the global gist of an image. People with Autism Spectrum Disorder (ASD) are generally outperformed by the typically developing population in tasks that require such global information processing. We tested a group of high-functioning adults with and without ASD on an explorative test battery of different ultra-rapid categorization tasks. As already reported in a previous study (Vanmarcke & Wagemans, 2015) gender differences (women better than men) were clearly present on all different categorization tasks (except for the motor baseline task). But, in contrast to our expectations, people with ASD only performed worse when the stimuli required the categorization of scenes depicting social interactions. These results argue against a general deficit in ultra-rapid gist perception of visual information in people with ASD. Instead of supporting the Weak Central Coherence (WCC) hypothesis (Frith & Happé, 1994; Happé & Frith, 2006), arguing for a slower, more effortful extraction of global meaning in people with ASD, this finding suggests a more specific problem with the fast processing of social relations.
Scalable Fact-checking with Human-in-the-Loop
Creators: name: Yang, Jing
name: Vega-Oliveros, Didier
name: Seibt, Tais
name: Rocha, Anderson
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: Researchers have been investigating automated solutions for fact-checking in a variety of fronts. However, current approaches often overlook the fact that the amount of information released every day is escalating, and a large amount of them overlap. Intending to accelerate fact-checking, we bridge this gap by grouping similar messages and summarizing them into aggregated claims. Specifically, we first clean a set of social media posts (e.g., tweets) and build a graph of all posts based on their semantics; Then, we perform two clustering methods to group the messages for further claim summarization. We evaluate the summaries both quantitatively with ROUGE scores and qualitatively with human evaluation. We also generate a graph of summaries to verify that there is no significant overlap among them. The results reduced 28,818 original messages to 700 summary claims, showing the potential to speed up the fact-checking process by organizing and selecting representative claims from massive disorganized and redundant messages.
description: Accepted in IEEE International Workshop on Information Forensics and Security - WIFS 2021, Montpellier, France
Explainable Fact-checking through Question Answering
Creators: name: Yang, Jing
name: Vega-Oliveros, Didier
name: Seibt, Taís
name: Rocha, Anderson
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Misleading or false information has been creating chaos in some places around the world. To mitigate this issue, many researchers have proposed automated fact-checking methods to fight the spread of fake news. However, most methods cannot explain the reasoning behind their decisions, failing to build trust between machines and humans using such technology. Trust is essential for fact-checking to be applied in the real world. Here, we address fact-checking explainability through question answering. In particular, we propose generating questions and answers from claims and answering the same questions from evidence. We also propose an answer comparison model with an attention mechanism attached to each question. Leveraging question answering as a proxy, we break down automated fact-checking into several steps -- this separation aids models' explainability as it allows for more detailed analysis of their decision-making processes. Experimental results show that the proposed model can achieve state-of-the-art performance while providing reasonable explainable capabilities.
description: 5 pages, 3 figures, 2 tables. Submitted to the 2022 International Conference on Acoustics, Speech, & Signal Processing (ICASSP)
The blue straggler population of the open clusters Trumpler 5, Trumpler 20, and NGC 2477
Creators: name: Rain, M. J
name: Carraro, G.
name: Ahumada, J.
name: Villanova, S.
name: Boffin, H.
name: Monaco, L.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present a study, based on Gaia DR2, of the population of blue straggler stars (BSS) in the open clusters Trumpler 5, Trumpler 20, and NGC 2477. All candidates were selected according to their position in the color-magnitude diagram, to their proper motion components, and to their parallax. We also looked for yellow stragglers, i.e., possible evolved blue stragglers. We found that Trumpler 5 hosts a large BSS population, which allowed us to analyze their radial distribution as a probe of the cluster's dynamical status. The BSS distribution was compared with that of red giant branch stars (RGB) to evaluate mass segregation. Our results indicate that blue straggler stars are not more centrally concentrated than RGB stars in any of the clusters. The radial distribution of BSS in Trumpler 5 is flat. Additionally, using a multi-epoch radial velocity survey conducted with the high-resolution spectrograph FLAMES/GIRAFFE at VLT, we measured the radial velocities of a sample of stragglers, for the sake of comparison with the mean radial velocity and the velocity dispersion of the clusters. Based on the radial velocity variations for different epochs, we roughly classified these stars as possible close-or long-period binaries.
description: 20 pages, 5 figures, accepted for publication in AJ
Efficiently Parallelizable Strassen-Based Multiplication of a Matrix by its Transpose
Creators: name: Arrigoni, Viviana
name: Maggioli, Filippo
name: Massini, Annalisa
name: Rodolà, Emanuele
Publisher: name: arXiv
Year: 2021
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: The multiplication of a matrix by its transpose, $A^T A$, appears as an intermediate operation in the solution of a wide set of problems. In this paper, we propose a new cache-oblivious algorithm (ATA) for computing this product, based upon the classical Strassen algorithm as a sub-routine. In particular, we decrease the computational cost to $\frac{2}{3}$ the time required by Strassen's algorithm, amounting to $\frac{14}{3}n^{\log_2 7}$ floating point operations. ATA works for generic rectangular matrices, and exploits the peculiar symmetry of the resulting product matrix for saving memory. In addition, we provide an extensive implementation study of ATA in a shared memory system, and extend its applicability to a distributed environment. To support our findings, we compare our algorithm with state-of-the-art solutions specialized in the computation of $A^T A$. Our experiments highlight good scalability with respect to both the matrix size and the number of involved processes, as well as favorable performance for both the parallel paradigms and the sequential implementation, when compared with other methods in the literature.
The spectra and composition of Ultra High Energy Cosmic Rays and the measurement of the proton-air cross section
Creators: name: Lipari, Paolo
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The shape of the longitudinal development of the showers generated in the atmosphere by very high energy cosmic ray particles encodes information about the mass composition of the flux, and about the properties of hadronic interactions that control the shower development. Studies of the energy dependence of the average and width of the depth of maximum distribution of showers with $E \gtrsim 10^{17.3}$ eV measured by the Pierre Auger Observatory, suggest, on the basis of a comparison with current models, that the composition of the cosmic ray flux undergoes a very important evolution, first becoming lighter and then rapidly heavier. These conclusions, if confirmed, would have profound and very surprising implications for our understanding of the high energy astrophysical sources. Studies of the shape of the depth of maximum distribution in the same energy range have been used by Auger and by the Telescope Array Collaboration to measure the interaction length of protons in air, a quantity that allows to estimate the $pp$ cross sections for values of $\sqrt{s}$ well above the LHC range. In this paper we argue that it is desirable to combine the studies of the cosmic ray composition with those aimed at the measurement of the $p$--air cross section. The latter allow to obtain estimates for the fraction of protons in the flux that can be of great help in decoding the composition and its energy dependence. Studies that consider multiple parameters to characterize the depth of maximum distributions also offer the possibility to perform more sensitive tests of the validity of the models used to describe high energy showers.
description: 39 pages, 19 figures
Graph Operations on Clique-Width Bounded Graphs
Creators: name: Gurski, Frank
Publisher: name: arXiv
Year: 2007
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: Discrete Mathematics (cs.DM)
subject: FOS: Computer and information sciences
subject: E.1; G.2.2

description: Clique-width is a well-known graph parameter. Many NP-hard graph problems admit polynomial-time solutions when restricted to graphs of bounded clique-width. The same holds for NLC-width. In this paper we study the behavior of clique-width and NLC-width under various graph operations and graph transformations. We give upper and lower bounds for the clique-width and NLC-width of the modified graphs in terms of the clique-width and NLC-width of the involved graphs.
description: 30 pages, to appear in "Theory of Computing Systems"
Photochromism and influence of point defect charge states on optical absorption in aluminum nitride (AlN)
Creators: name: Gamov, Ivan
name: Hartmann, Carsten
name: Straubinger, Thomas
name: Bickermann, Matthias
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In this work, we study the absorption properties of AlN in the range of 1.5 - 5.5 eV, as well as the meta-stable change in absorption induced by ultraviolet (UV) irradiation (photochromism), and the restoration of the initial state under the action of irradiation of 2 - 4 eV or elevated temperatures. UV irradiation results in a decrease of the absorption coefficient from 110 cm$^{-1}$ to 55 cm$^{-1}$ at 4.7 eV while in the visible range the absorption coefficient increases from values below 5 cm$^{-1}$ to ~35 cm$^{-1}$. Measurements with two linear polarizations, parallel and perpendicular to the optical axis, provide determination of several different absorption bands at 2.6, 2.8, 3.4, 4.0, 4.5, and 4.8 eV. The bands at 2.6 eV and 3.4 eV identify the defect levels near to the valence band, while the band peaking at 2.8 eV is related to the conduction band. The photochromism allows controlling the absorption of light in two related spectral ranges because the decrease of UV absorption and increase of the visible absorption are related to switching the charge state of the same defects.
description: 37 pages, 8 figures, 2 tables
Oriented and unitary equivariant bordism of surfaces
Creators: name: Angel, Andrés
name: Samperton, Eric
name: Segovia, Carlos
name: Uribe, Bernardo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 57R85, 55N22, 57R75, 57R77

description: Fix a finite group $G$. We study $Ω^{SO,G}_2$ and $Ω^{U,G}_2$, the unitary and oriented bordism groups of smooth $G$-equivariant compact surfaces, respectively, and we calculate them explicitly. Their ranks are determined by the possible representations around fixed points, while their torsion subgroups are isomorphic to the direct sum of the Bogomolov multipliers of the Weyl groups of representatives of conjugacy classes of all subgroups of $G$. We present an alternative proof of the fact that surfaces with free actions which induce non-trivial elements in the Bogomolov multiplier of the group cannot equivariantly bound. This result permits us to show that the 2-dimensional SK-groups (Schneiden und Kleben, or ``cut and paste") of the classifying spaces of a finite group can be understood in terms of the bordism group of free equivariant surfaces modulo the ones that bound arbitrary actions.
description: To appear in AG&T. 37 pages. Lemma 4.14 has been amended
Averaging Spherically Symmetric Spacetimes in General Relativity
Creators: name: Coley, A. A.
name: Pelavas, N.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We discuss the averaging problem in general relativity, using the form of the macroscopic gravity equations in the case of spherical symmetry in volume preserving coordinates. In particular, we calculate the form of the correlation tensor under some reasonable assumptions on the form for the inhomogeneous gravitational field and matter distribution. On cosmological scales, the correlation tensor in a Friedmann-Lema\^ıtre-Robertson-Walker (FLRW) background is found to be of the form of a spatial curvature. On astrophysical scales the correlation tensor can be interpreted as the sum of a spatial curvature and an anisotropic fluid. We briefly discuss the physical implications of these results.
description: 6 pages
NASA CryoCloud American Geophysical Union Recognition Prize presentation (December 2023)
Creators: name: Snow, Tasha
name: Millstein, Joanna
name: Sauthoff, Wilson
name: Scheick, Jessica
name: Leong, Wei Ji
name: Colliander, James
name: Munroe, James
name: Pérez, Fernando
name: Felikson, Denis
name: Sutterley, Tyler
name: Fisher, Matthew
name: Sapienza, Facundo
name: Abrahams, Ellianna
name: Zheng, Whyjay
name: Siegfried, Matthew
Publisher: name: Zenodo
Year: 2024
Subjects: open science
cloud computing
JupyterHub
NASA
cryosphere
Project Jupyter

description: American Geophysical Union Open Science Recognition Prize presentation. Abstract: The majority of success achieved in innovation stems not from technological advancements but from the accompanying social advancements, such as those in community practices, strategies, morals, educational approaches, and inclusivity. NASA, the US federal government, and numerous US academic institutions have declared 2023 the Year of Open Science, with a mission to innovate the scientific process and expand impact through open science. Many core tools in science—such as computers, software, and data—have begun to undergo a massive evolution, with technological advances changing the realm of possible questions in science. The virtual cloud, where much of this evolution is occurring, offers an opportunity to accelerate open science through tools that can broaden access, enhance the transparency of the scientific process, facilitate reproducibility, and expand inclusivity in science. However, with these emerging technologies, scientists must innovate the social constructs surrounding how we use these tools, collaborate, and build community. To address these challenges, we have built upon state-of-the-art open cloud infrastructure, known as the NASA CryoCloud (cryointhecloud.com) JupyterHub, to create a holistic open science community ecosystem, in this case, curated for NASA Cryosphere communities. Utilizing feedback from over 240 CryoCloud users, small teams, and event organizers, we designed new cloud tools—actively tested by the community—and developed community best practices to streamline scientific workflows, and enhance community collaboration and interconnectedness. Together, these two facets of innovation have worked to make scientific computing more intuitive, cost- and time-efficient, and open for all, facilitating NASA’s open-source, interconnected, and science-accelerated vision of the future.
description: This work was funded by the NASA Transform to Open Science program (grant 80NSSC23K0002), and the NASA Cryosphere Program and ICESat-2 Science Team (grant 80NSSC22K1877).
A Distance-Deviation Consistency and Model-Independent Method to Test the Cosmic Distance-Duality Relation
Creators: name: Zhou, C. C.
name: Hu, J.
name: LI, M. C.
name: Zhang, X.
name: Fang, G. W.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: A distance-deviation consistency and model-independent method to test the cosmic distance duality relation (CDDR) is provided. The method is worth attention on two aspects: firstly, a distance-deviation consistency method is used to pair subsamples: instead of pairing subsamples with redshift deviation smaller than a \textbf{value}, say $\left\vert Δz\right\vert <0.005$. The redshift deviation between subsamples decreases with the redshift to ensure the distance deviation stays the same. The method selects more subsamples at high redshift, up to $z=2.16$, and provides 120 subsample pairs. Secondly, the model-independent method involves the latest data set of $1048$ type Ia supernovae (SNe Ia) and $205$ strong gravitational lensing systems (SGLS), which are used to obtain the luminosity distances $D_L$ and the ratio of angular diameter distance $D_A$ respectively. With the model-independent method, parameters of the CDDR, the SNe Ia light-curve, and the SGLS are fitted simultaneously. \textbf{The result shows} that $η= 0.047^{+0.190}_{-0.151}$ and CDDR is validated at 1$σ$ confidence level for the form $\frac{D_L}{D_A}{(1 + z)^{ - 2}} =1+ ηz$.
description: 7 pages, 3 figures
A monotonicity result for the first Steklov-Dirichlet Laplacian eigenvalue
Creators: name: Gavitone, Nunzia
name: Piscitelli, Gianpaolo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: In this paper, we consider the first Steklov-Dirichlet eigenvalue of the Laplace operator in annular domain with a spherical hole. We prove a monotonicity result with respect the hole, when the outer region is centrally symmetrc.
Constraining $H_0$ from Sunyaev-Zel'dovich effect, Galaxy Clusters X-ray data, and Baryon Oscillations
Creators: name: Cunha, J. V.
name: Marassi, L.
name: Lima, J. A. S.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Estimates of $H_0$ from Sunyaev-Zel'dovich effect (SZE) and X-ray surface brightness of galaxy clusters depends on the underlying cosmology. In the current $Λ$CDM flat cosmology, a possible technique to broke the degenerescency on the mass density parameter ($Ω_{m}$) is to apply a joint analysis involving the baryon acoustic oscillations (BAO). By adopting this technique to the ($H_0, Ω_m$) parameter space, we obtain new constraints on the Hubble constant $H_0$ from BAO signature as given by the Sloan Digital Sky Survey (SDSS) catalog. Our analysis based on the SZE/X-ray data for a sample of 25 clusters yields $H_0= 74^{+4}_{-3.5}$ km s$^{-1}$ Mpc$^{-1}$ ($1σ$, neglecting systematic uncertainties). This result is in good agreement with independent studies from the {\it{Hubble Space Telescope}} key project and the recent estimates of WMAP, thereby suggesting that the combination of these three independent phenomena provides an interesting method to constrain the Hubble constant.
description: 15 pages, 4 figures, 1 table
The local Tamagawa number conjecture for Hecke characters, II
Creators: name: Bars, Francesc
Publisher: name: arXiv
Year: 2007
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11G40 (11G55, 11R42, 14G10, 19F27)

description: In this paper we prove the weak local Tamagawa number conjecture for the remaining non-critical cases for the motives associated to Hecke characters $ψ_θ:\mathbb{A}_K\to K^*$ of the author's previous paper, where $K$ is an imaginary quadratic field with $cl(K)=1$, under certain restrictions which originate mainly from the Iwasawa theory of imaginary quadratic fields.
description: The preprint "The local Tamagawa number conjecture for Hecke characters, II", appeared as section 6 of the present manuscript, which includes two old prepints of the author, under the joint title "On the Tamagawa number conjecture for Hecke characters"
Heterogeneous network with distance dependent connectivity
Creators: name: Medo, Matus
name: Smrek, Jan
Publisher: name: arXiv
Year: 2008
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: We investigate a network model based on an infinite regular square lattice embedded in the Euclidean plane where the node connection probability is given by the geometrical distance of nodes. We show that the degree distribution in the basic model is sharply peaked around its mean value. Since the model was originally developed to mimic the social network of acquaintances, to broaden the degree distribution we propose its generalization. We show that when heterogeneity is introduced to the model, it is possible to obtain fat tails of the degree distribution. Meanwhile, the small-world phenomenon present in the basic model is not affected. To support our claims, both analytical and numerical results are obtained.
description: 6 pages, 4 figures, minor clarifications and references added
Measuring the Average Evolution of Luminous Galaxies at z<3: The Rest-frame Optical Luminosity Density, Spectral Energy Distribution, and Stellar Mass Density
Creators: name: Rudnick, Gregory
name: Labbe, Ivo
name: Schreiber, Natascha M. Foerster
name: Wuyts, Stijn
name: Franx, Marijn
name: Finlator, Kristian
name: Kriek, Mariska
name: Moorwood, Alan
name: Rix, Hans-Walter
name: Roettgering, Huub
name: Trujillo, Ignacio
name: van der Wel, Arjen
name: van der Werf, Paul
name: van Dokkum, Pieter G.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: (Abridged) We present the evolution of the volume averaged properties of the rest-frame optically luminous galaxy population to z~3, determined from four disjoint deep fields with optical to near-infrared wavelength coverage. We select galaxies above a rest-frame V-band luminosity of 3x10^10 Lsol and characterize their rest-frame UV through optical properties via the mean spectral energy distribution (SED). To measure evolution we apply the same selection criteria to a sample of galaxies from the Sloan Digital Sky Survey and COMBO-17. The mean rest-frame 2200Ang through V-band SED becomes steadily bluer with increasing redshift but at z<3 the mean SED falls within the range defined by ``normal'' galaxies in the nearby Universe. We measure stellar mass-to-light ratios (Mstar/L) by fitting models to the rest-frame UV-optical SEDs and derive the stellar mass density. The stellar mass density in luminous galaxies has increased by a factor of 3.5-7.9 from z=3 to z=0.1, including field-to-field variance uncertainties. After correcting to total, the measured mass densities at z<2 lie below the integral of the star formation rate (SFR) density as a function of redshift as derived from UV selected samples. This may indicate a systematic error in the mass densities or SFR(z) estimates. We find large discrepancies between recent model predictions for the evolution of the mass density and our results, even when our observational selection is applied to the models. Finally we determine that Distant Red Galaxies (selected to have J_s - K_s>2.3) in our LV selected samples contribute 30% and 64% of the stellar mass budget at z~2 and z~ 2.8 respectively. These galaxies are largely absent from UV surveys and this result highlights the need for mass selection of high redshift galaxies.
description: Accepted for publication in the Astrophysical Journal, 24 pages, 16 figures
Likelihood estimation of places in local environments
Creators: name: Lancier, Stephan
name: Mallot, Hanspeter A.
Publisher: name: F1000Research
Year: 2015

description: Place recognition is based on long-term memory codes providing local position information. We propose a Maximum-Likelihood model of place recognition taking into account stored and perceived landmark distances and bearings. Stored landmark distance is assumed to be based on triangulation and is therefore veridical. Landmark distance perceived during homing are assumed to be hyperbolically compressed (Gilinsky, 1951).

We evaluate the model with experimental data which was collected from place recognition experiments in a virtual reality setup. Three groups of participants learned a goal location within three different configurations of four distinguishable landmarks (parallelogram, irregular with large distance variation between landmarks, irregular with homogeneous distances). In the following test phase the participants navigated to the goal location, but the environment was now covered by “ground fog” removing all environmental information except the landmarks themselves. Error ellipses were elongated towards the most distant landmark and, in the irregular conditions, showed a systematic bias in the same direction. The model reproduces the ellipse orientations if we assume that distance measurements are less noisy for near distances (from about 30 m) than bearing measurements; it also reproduces the systematic biases due to the hyperbolic compression of perceived distances (Gilinsky’s A = 90 m).
Lexical elicitation: voice quality; Mann 476-500
Creators: name: Amartmontri, Khamma
name: Lau-Preechathammarach, Raksit Tyler
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2023
Subjects: subject: sss

description: Elicitation of words differing only in voice quality (modal, breathy) and words from Mann's MSEA Swadesh list 476-500. Consultant is a 40-year-old male.