cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Managing and governing integrated research programmes: Lessons from theory and practice
Creators: name: Wever, Mark
name: Romera, Alvaro
name: Shah, Syed
name: Wognum, Nel
Publisher: name: AgResearch
Year: 2023
Subjects: Engineering
Engineering practice and education

description: Researchers are increasingly working in large, integrated science programmes. This is supposed to lead to several benefits, including creating and enhancing synergies amongst projects, improving collaboration and knowledge exchanges amongst researchers from different disciplines, and generating a higher return on investments in R&D. In practice, though, these benefits are often not fully realised, and large-scale integrated programmes can become frustrating for researchers. Additionally, they can result in insufficient integration and collaboration, and incur high overhead costs. In the present paper, the authors share their experience and insights on how to structure, manage and govern integrated programmes more competently. They do so by reflecting on their own practical experience in designing an integrated programme, and by drawing valuable insights from the literature on governance, management studies and organisational economics. The authors suggest that many problems can be linked to the implementation of programme management systems and coordination mechanisms that are poorly aligned with the unique characteristics of integrated programmes. They provide guidelines for programme managers to use systems that are a better fit, which can help researchers collaborate in a more engaging and productive manner while reducing the overhead costs associated with programme administration. NZBIDA
Universal scaling of gluon and ghost propagators in the infrared
Creators: name: Siringo, Fabio
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A universal behavior is predicted for ghost and gluon propagators in the infrared. The universal behavior is shown to be a signature of a one-loop approximation and emerges naturally by the massive expansion that predicts universal analytical functions for the inverse dressing functions that do not depend on any parameter or color number. By a scaling of units and by adding an integration constant, all lattice data, for different color numbers (and even quark content for the ghosts), collapse on the same universal curves predicted by the massive expansion.
Cosmic Inflation from Emergent Spacetime Picture
Creators: name: Yang, Hyun Seok
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We argue that the emergent spacetime picture admits a background-independent formulation of cosmic inflation. The inflation in this picture corresponds to the dynamical emergence of spacetime while the conventional inflation is simply an (exponential) expansion of a preexisting spacetime owing to the vacuum energy carried by an inflaton field. We show that the cosmic inflation arises as a time-dependent solution of the matrix quantum mechanics describing the dynamical process of Planck energy condensate in vacuum without introducing any inflaton field as well as an {\it ad hoc} inflation potential. Thus the emergent spacetime picture realizes a background-independent description of the inflationary universe which has a sufficiently elegant and explanatory power to defend the integrity of physics against the multiverse hypothesis.
description: 6 pages, 1 figure; Contribution to the Proceedings of the Second LeCosPA Symposium "Everything about Gravity", Taipei, 14-18 December, 2015
Fully automatic visual servoing control for underwater vehiclemanipulator systems based on a heuristic inverse kinematics
Creators: name: Santos, Phillipe
name: Freire, Raimundo C. S.
name: CARVALHO, Elyson Adam Nunes
name: Molina, Lucas
name: Freire, Eduardo O.
name: Santos, Matheus
name: WEIR, ANTHONY
name: Trslic, Petar
name: OMERDIC, EDIN
name: DOOLY, GERARD
name: TOAL, DANIEL
Publisher: name: University of Limerick
Year: 2023
Subjects: classificationCode: 400905
subject: Electronic instrumentation
classificationCode: 40
subject: Engineering

description: The use of underwater vehicle manipulator systems (UVMS) equipped with cameras has gained significant attention due to their capacity to perform underwater tasks autonomously. However, controlling both the manipulator and the remotely operated vehicle (ROV) based on the vision system information is not an easy task, especially in situations where the vehicle cannot be parked/held stationary. Most of the existing approaches work based on complex matrix calculations for the inverse kinematics (IK), which can lead to high computational costs and the need to deal with singularity problems. A problem arises when the amount of time needed to calculate the UVMS configuration can result in reduced frequency of target pose estimation, beyond the point where the target has moved out of the camera field of view. Therefore, this paper proposes an autonomous visual servoing approach for UVMS, including an extension of a heuristic technique named M-FABRIK (Mobile - Forward and Backward Reaching IK) to calculate the UVMS inverse kinematics in a simple and fast way. This approach aims to control both the configuration of the manipulator and ROV position in order to allow underwater intervention in situations where the ROV cannot be parked/held stationary. This solution allows the vehicle to be positioned according to additional criteria, besides avoiding matrix inversion and being robust to singularities. Trials have been performed with a manipulator mounted on a work-class ROV for an autonomous underwater monitoring task and results demonstrate a simple and fast approach, which is able to set the configuration of the manipulator as well as the ROV for visual servoing applications in real-time, such as for monitoring, tracking and intervention tasks underwater.
Pointwise convergence of almost periodic Fourier series and associated series of dilates
Creators: name: Cuny, Christophe
name: Weber, Michel
Publisher: name: arXiv
Year: 2016
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: Primary 42A75, Secondary 42A24, 42B25

description: Let $\mathcal S^2$ be the Stepanov space and let $ λ_n\uparrow\infty$. Let $(a_n)_{n\ge 1}$ be satisfying Wiener's condition $A:= \sum_{n\ge 1} \big(\sum_{k\, :\, n\le λ_k \le n+1}|a_k|\big)^2 0$ denotes a universal constant. Moreover, the series $\sum_{n\ge 1} a_n{\rm e}^{itλ_n }$ converges for $λ$-a.e. $t\in \mathbb R$. This contains as a special case Hedenmalm and Saksman result for Dirichlet series. We also obtain maximal inequalities for corresponding series of dilates. Let $1\le p,q\le 2$ be such that $1/p+1/q=3/2$. Then for any sequence $(α_n)_{n\ge 1}$ and $(β_n)_{n\ge 1}$ of complex numbers such that $K:=\sum_{n\ge 1} \big(\sum_{k\,:\, n\le λ_k< n+1}|α_k|\,\big)^p
description: 15 pages
Recommender Systems for Online and Mobile Social Networks: A survey
Creators: name: Campana, Mattia Giovanni
name: Delmastro, Franca
Publisher: name: arXiv
Year: 2023
Subjects: subject: Information Retrieval (cs.IR)
subject: Machine Learning (cs.LG)
subject: Social and Information Networks (cs.SI)
subject: FOS: Computer and information sciences

description: Recommender Systems (RS) currently represent a fundamental tool in online services, especially with the advent of Online Social Networks (OSN). In this case, users generate huge amounts of contents and they can be quickly overloaded by useless information. At the same time, social media represent an important source of information to characterize contents and users' interests. RS can exploit this information to further personalize suggestions and improve the recommendation process. In this paper we present a survey of Recommender Systems designed and implemented for Online and Mobile Social Networks, highlighting how the use of social context information improves the recommendation task, and how standard algorithms must be enhanced and optimized to run in a fully distributed environment, as opportunistic networks. We describe advantages and drawbacks of these systems in terms of algorithms, target domains, evaluation metrics and performance evaluations. Eventually, we present some open research challenges in this area.
Liminal Spaces, and Identity Transformations in South Asian Literatures and Arts
Creators: name: Rossi Paola, M.
Publisher: name: Zenodo
Year: 2023

description: This is the accepted manuscript (post-print) of the book Liminal Spaces, and Identity Transformations in South Asian Literatures and Arts. Final version will be published as soon as possible at: https://libri.unimi.it/index.php/consonanze/catalog/book/139 The present volume is a collection of 16 papers presented at the International Seminar ‘Liminal Spaces, and Identity Transformations in Indian Cultural History’ in Milan, in September 2019, when we were on the brink of a historical change unknowingly. And afterwards, during the pandemic experience, exploring liminality, as category of reality applied to Indian culture and especially to art and literature, appeared to be a means to cope with an emergency the likes of which had never been seen before. Obviously, this work does not aspire to be exhaustive, nonetheless, the heterogeneity of the contributions offers a multifaceted perspective: in actual fact, since liminality implies potentially myriads of interpretations, it appears to provide us with one of the main keys to addressing the entanglement of reality, especially the complexity of the Indian civilization, past and present. The focus is particularly on the literary and artistic aspects of such an extraordinary cultural heritage, from the Vedic period up to modernity; literature and arts are the lens through which variegated anthropological issues, crossing different historical phases, are investigated: firstly, the ritual question, in compliance with van Gennep and Turner’s approach, but also religious experiences, sovereignty and violence, dialectics of identity, social dynamics, gender identity, etc. Literature and arts, but still by means of their own aesthetic devices, mirror critical points characterising such issues, as if poetry and artwork, zooming in on specific transition elements, were themselves on the threshold of manifold layers of reality, able to pass through their interstitial discontinuities. Finally, it is a great honour to dedicate such a volume to the memory of Professor Alexander Dubyanskiy (1941–2020), eminent scholar in Indian literature, especially in Tamil poetry, who experienced multiple aspects of liminality both of the South Asian culture and life.
Multipolar nonlinear nanophotonics
Creators: name: Smirnova, Daria
name: Kivshar, Yuri S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Nonlinear nanophotonics is a rapidly developing field with many useful applications for a design of nonlinear nanoantennas, light sources, nanolasers, sensors, and ultrafast miniature metadevices. A tight confinement of the local electromagnetic fields in resonant photonic nanostructures can boost nonlinear optical effects, thus offering versatile opportunities for subwavelength control of light. To achieve the desired functionalities, it is essential to gain flexible control over the near- and far-field properties of nanostructures. Thus, both modal and multipolar analyses are widely exploited for engineering nonlinear scattering from resonant nanoscale elements, in particular for enhancing the near-field interaction, tailoring the far-field multipolar interference, and optimization of the radiation directionality. Here, we review the recent advances in this recently emerged research field ranging from metallic structures exhibiting localized plasmonic resonances to hybrid metal-dielectric and all-dielectric nanostructures driven by Mie-type multipolar resonances and optically-induced magnetic response.
description: 17 pages, 6 figures
Emergent Spacetime for Quantum Gravity
Creators: name: Yang, Hyun Seok
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We emphasize that noncommutative (NC) spacetime necessarily implies emergent spacetime if spacetime at microscopic scales should be viewed as NC. In order to understand NC spacetime correctly, we need to deactivate the thought patterns that we have installed in our brains and taken for granted for so many years. Emergent spacetime allows a background-independent formulation of quantum gravity that will open a new perspective to resolve the notorious problems in theoretical physics such as the cosmological constant problem, hierarchy problem, dark energy, dark matter, and cosmic inflation.
description: 10 pages, 2 figures; Plenary talk at the Second LeCosPA Symposium "Everything about Gravity", Taipei, 14-18 December, 2015
An Active Set Algorithm for Nonlinear Optimization with Polyhedral Constraints
Creators: name: Hager, William W.
name: Zhang, Hongchao
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: A polyhedral active set algorithm PASA is developed for solving a nonlinear optimization problem whose feasible set is a polyhedron. Phase one of the algorithm is the gradient projection method, while phase two is any algorithm for solving a linearly constrained optimization problem. Rules are provided for branching between the two phases. Global convergence to a stationary point is established, while asymptotically PASA performs only phase two when either a nondegeneracy assumption holds, or the active constraints are linearly independent and a strong second-order sufficient optimality condition holds.
Enzymes for consumer products to achieve climate neutrality
Creators: name: Molina-Espeja, Patricia
name: Sanz-Aparicio, Julia
name: Golyshin, Peter N.
name: Robles-Martín, Ana
name: Guallar, Víctor
name: Beltrametti, Fabrizio
name: Müller, Markus
name: Yakimov, Michail M.
name: Modregger, Jan
name: Van Logchem, Moniec
name: Corvini, Philippe
name: Shahgaldian, Patrick
name: Degering, Christian
name: Wieland, Susanne
name: Timm, Anne
name: De Carvalho, Carla C. C. R.
name: Re, Ilaria
name: Daniotti, Sara
name: Thies, Stephan
name: Jaeger, Karl-Erich
name: Chow, Jennifer
name: Streit, Wolfgang R.
name: Lottenbach, Roland
name: Rösch, Rainer
name: Ansari, Nazanin
name: Ferrer, Manuel
Publisher: name: Oxford University Press
Year: 2023
Subjects: subject: 600 - Technik, Medizin, angewandte Wissenschaften

description: Abstract Today, the chemosphere’s and biosphere’s compositions of the planet are changing faster than experienced during the past thousand years. CO2 emissions from fossil fuel combustion are rising dramatically, including those from processing, manufacturing and consuming everyday products; this rate of greenhouse gas emission (36.2 gigatons accumulated in 2022) is raising global temperatures and destabilizing the climate, which is one of the most influential forces on our planet. As our world warms up, our climate will enter a period of constant turbulence, affecting more than 85% of our ecosystems, including the delicate web of life on these systems, and impacting socioeconomic networks. How do we deal with the green transition to minimize climate change and its impacts while we are facing these new realities? One of the solutions is to use renewable natural resources. Indeed, nature itself, through the working parts of its living systems, the enzymes, can significantly contribute to achieve climate neutrality and good ecological/biodiversity status. Annually they can help decreasing CO2 emissions by 1–2.5 billion-tons, carbon demand by about 200 million-tons, and chemical demand by about 90 million-tons. With current climate change goals, we review the consequences of climate change at multiple scales and how enzymes can counteract or mitigate them. We then focus on how they mobilize sustainable and greener innovations in consumer products that have a high contribution to global carbon emissions. Finally, key innovations and challenges to be solved at the enzyme and product levels are discussed.
CanIsoNet: a database to study the functional impact of isoform switching events in diseases
Creators: name: Karakulak, Tülay
name: Szklarczyk, Damian
name: Saylan, Cemil Can
name: Moch, Holger
name: Von Mering, Christian
name: Kahraman, Abdullah
Publisher: name: Oxford University Press
Year: 2023
Subjects: subject: 600 - Technik, Medizin, angewandte Wissenschaften

description: Motivation: Alternative splicing, as an essential regulatory mechanism in normal mammalian cells, is frequently disturbed in cancer and other diseases. Switches in the expression of most dominant alternative isoforms can alter protein interaction networks of associated genes giving rise to disease and disease progression. Here, we present CanIsoNet, a database to view, browse and search isoform switching events in diseases. CanIsoNet is the first webserver that incorporates isoform expression data with STRING interaction networks and ClinVar annotations to predict the pathogenic impact of isoform switching events in various diseases. Results: Data in CanIsoNet can be browsed by disease or searched by genes or isoforms in annotation-rich data tables. Various annotations for 11 811 isoforms and 14 357 unique isoform switching events across 31 different disease types are available. The network density score for each disease-specific isoform, PFAM domain IDs of disrupted interactions, domain structure visualization of transcripts and expression data of switched isoforms for each sample is given. Additionally, the genes annotated in ClinVar are highlighted in interactive interaction networks. Availability and implementation: CanIsoNet is freely available at https://www.caniso.net. The source codes can be found under a Creative Common License at https://github.com/kahramanlab/CanIsoNet_Web.
Damping of Alfven waves by Turbulence and its Consequences: from Cosmic-Rays Streaming to Launching Winds
Creators: name: Lazarian, A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: This paper considers turbulent damping of Alfven waves in magnetized plasmas. We identify two cases of damping, one related to damping of cosmic rays streaming instability, the other related to damping of Alfven waves emitted by a macroscopic wave source, e.g. stellar atmosphere. The physical difference between the two cases is that in the former case the generated waves are emitted in respect to the local direction of magnetic field, in the latter in respect to the mean field. The scaling of damping is different in the two cases. We the regimes of turbulence ranging from subAlfvenic to superAlfvenic we obtain analytical expressions for the damping rates and define the ranges of applicability of these expressions. Describing the damping of the streaming instability, we find that for subAlfvenic turbulence the range of cosmic ray energies influenced by weak turbulence is unproportionally large compared to the range of scales that the weak turbulence is present. On the contrary, the range of cosmic ray energies affected by strong Alfvenic turbulence is rather limited. A number of astrophysical applications of the process ranging from launching of stellar and galactic winds to propagation of cosmic rays in galaxies and clusters of galaxies is considered. In particular, we discuss how to reconcile the process of turbulent damping with the observed isotropy of the Milky Way cosmic rays.
description: 18 pages, submitted to ApJ
On the fractional probabilistic Taylor's and mean value theorems
Creators: name: Di Crescenzo, Antonio
name: Meoli, Alessandra
Publisher: name: arXiv
Year: 2016
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60E99, 26A33, 26A24

description: In order to develop certain fractional probabilistic analogues of Taylor's theorem and mean value theorem, we introduce the nth-order fractional equilibrium distribution in terms of the Weyl fractional integral and investigate its main properties. Specifically, we show a characterization result by which the nth-order fractional equilibrium distribution is identical to the starting distribution if and only if it is exponential. The nth-order fractional equilibrium density is then used to prove a fractional probabilistic Taylor's theorem based on derivatives of Riemann-Liouville type. A fractional analogue of the probabilistic mean value theorem is thus developed for pairs of nonnegative random variables ordered according to the survival bounded stochastic order. We also provide some related results, both involving the normalized moments and a fractional extension of the variance, and a formula of interest to actuarial science. In conclusion we discuss the probabilistic Taylor's theorem based on fractional Caputo derivatives.
description: 19 pages
title: The Last Tower [board game]
Creators: name: Kramer, Stefan
Publisher: name: American University digital repository
Year: 2022

description: A board game for 2-4 players aged 8 and above, more suitable for younger players due to reliance on element of luck (rolling of the die). The downloadable ZIP file contains: 1.) a PDF file with instructions; 2.) PDF files of the game board in two paper sizes (explained in instructions file); 3.) a photo of the game in progress. Additional pieces required to play: stackable game tokens (explained in instructions file) and one six-sided die.
Data from: The gut microbiome and early-life growth in a population with high prevalence of stunting
Creators: name: Robertson, Ruairi
name: Edens, Thaddeus
name: Manges, Amee
Publisher: name: Zenodo
Year: 2022

description: The gut microbiome of rural Zimbabwean infants undergoes programmed maturation that is unresponsive to sanitation and nutrition interventions but is strongly associated with maternal HIV infection and can moderately predict linear growth.
Self-similar Turing Patterns: An Anomalous diffusion consequence
Creators: name: Hernández, D.
name: Herrera-Hernández, E. C.
name: Núñez-López, M.
name: Hernández-Coronado, H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: In this work we show that under specific anomalous diffusion conditions, chemical systems can produce well-ordered self-similar concentration patterns through a diffusion-driven instability. We also find spiral patterns and patterns with mixtures of rotational symmetries not reported before. The type of anomalous diffusion discussed in this work, either subdiffusion or superdiffusion, is a consequence of the medium heterogeneity, and is modelled through a space-dependent diffusion coefficient with a power-law functional form.
A generalized scattering theory in quantum mechanics
Creators: name: Wang, Huai-Yu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In quantum mechanics textbooks, a single-particle scattering theory is introduced. In the present work, a generalized scattering theory is presented, which can be in principle applied to the scattering problems of arbitrary number of particle. In laboratory frame, a generalized Lippmann-Schwinger scattering equation is derived. We emphasized that the derivation is rigorous, even for treating infinitesimals. No manual operation such as analytical continuation is allowed. In the case that before scattering N particles are plane waves and after the scattering they are new plane waves, the transition amplitude and transition probability are given and the generalized S matrix is presented. It is proved that the transition probability from a set of plane waves to a new set of plane waves of the N particles equal to that of the reciprocal process. The generalized theory is applied to the cases of one- and two-particle scattering as two examples. When applied to single-particle scattering problems, our generalized formalism degrades to that usually seen in the literature. When our generalized theory is applied to two-particle scattering problems, the formula of the transition probability of two-particle collision is given. It is shown that the transition probability of the scattering of two free particles is identical to that of the reciprocal process. This transition probability and the identity are needed in deriving Boltzmann transport equation in statistical mechanics. The case of identical particles is also discussed.
description: 35 pages, 3figures
Jets of SS433 on scales of dozens parsecs
Creators: name: Panferov, Alexander A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The radio nebula W50 harbours the relativistic binary system SS433, which is a source of the powerful wind and jets. The origin of W50 is wrapped in the interplay of the wind, supernova remnant and jets. The evolution of the jets on the scales of the nebula is a Rosetta stone for its origin. To disentangle the roles of these components, we study physical conditions of the jets propagation inside W50, and determine deceleration of the jets. The morphology and parameters of the interior of W50 are analyzed using the available observations of the eastern X-ray lobe, which traces the jet. In order to estimate deceleration of this jet, we devised a simplistic model of the viscous interaction, via turbulence, of a jet with the ambient medium, which would fit mass entrainment from the ambient medium into the jets of the radio galaxy 3C31, the well studied case of continuously decelerating jets. X-ray observations suggest that the eastern jet persists through W50 as hollow one, and is recollimated to the opening $\sim 30^\circ$. From the thermal emission of the eastern X-ray lobe, we determine a pressure of $P \sim 3\cdot 10^{-11}$ erg/cm$^3$ inside W50. In the frame of a theory of the dynamics of radiative supernova remnants and stellar wind bubbles, this pressure in combination with other known parameters restricts W50's origin to a supernova happened $\sim 100\,000$ yr ago. Also, this pressure in our entrainment model gives a deceleration of the jet by $\sim 60\%$ in the bounds of W50's spherical component, of radius $\sim 40$ pc. In this case, the age of the jet should be $\ll 27\,000$ yr so as to satisfy the sphericity of W50. The entrainment model comes to the viscous stress in a jet of a form $σ= αP$, where the viscosity parameter $α$ is predefined by the model.
description: 14 pages, 4 figures
The allostery landscape: quantifying thermodynamic couplings in biomolecular systems
Creators: name: Cuendet, Michel A.
name: Weinstein, Harel
name: LeVine, Michael V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Biomolecules (q-bio.BM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Allostery plays a fundament role in most biological processes. However, little theory is available to describe it outside of two-state models. Here we use a statistical mechanical approach to show that the allosteric coupling between two collective variables is not a single number, but instead a two-dimensional thermodynamic coupling function that is directly related to the mutual information from information theory and the copula density function from probability theory. On this basis, we demonstrate how to quantify the contribution of specific energy terms to this thermodynamic coupling function, enabling a decomposition that reveals the mechanism of allostery. We illustrate the thermodynamic coupling function and its use by showing how allosteric coupling in the alanine dipeptide molecule contributes to the overall shape of the Φ/Ψ free energy surface, and by identifying the interactions that are necessary for this coupling.
description: In review at Journal of Chemical Theory and Computation
One-particle density matrix characterization of many-body localization
Creators: name: Bera, Soumya
name: Martynec, Thomas
name: Schomerus, Henning
name: Heidrich-Meisner, Fabian
name: Bardarson, Jens H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study a model of interacting fermions in one dimension subject to random, uncorrelated onsite disorder. The model realizes an interaction-driven quantum phase transition between an ergodic and a many-body localized phase (MBL). We propose a single-particle framework to characterize these phases by the eigenstates (the natural orbitals) and the eigenvalues (the occupation spectrum) of the one-particle density matrix (OPDM) in many-body eigenstates. As a main result, we find that the natural orbitals are localized in the MBL phase, but delocalized in the ergodic phase. This qualitative change in these single-particle states is a many-body effect, since without interactions the single-particle energy eigenstates are all localized. The occupation spectrum in the ergodic phase is thermal in agreement with the eigenstate thermalization hypothesis, while in the MBL phase the occupations preserve a discontinuity at an emergent Fermi edge. This suggests that the MBL eigenstates are weakly dressed Slater determinants, with the eigenstates of the underlying Anderson problem as reference states. We discuss the statistical properties of the natural orbitals and of the occupation spectrum in the two phases and as the transition is approached. Our results are consistent with the existing picture of emergent integrability and localized integrals of motion, or quasiparticles, in the MBL phase. We emphasize the close analogy of the MBL phase to a zero-temperature Fermi liquid: in the studied model, the MBL phase is adiabatically connected to the Anderson insulator and the occupation-spectrum discontinuity directly indicates the presence of quasiparticles localized in real space. Finally, we show that the same picture emerges for interacting fermions in the presence of an experimentally-relevant bichromatic lattice and thereby demonstrate that our findings are not limited to a specific model.
description: 19 pages, 20 figures
Planetary Climates and Critical Thinking in STEAM Education
Creators: name: Tamazawa, Harufumi
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Planetary Climates and Critical Thinking in STEAM Education

Presenter: Harufumi Tamazawa (University of Tokyo / Kyoto City Univ. of Arts, Japan)

 

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

When the discussion of planetary climate is used in education, it is often stressed that the importance of conservation of the global environment and the survival of humankind is important. Considering that the timescale of astronomy is longer than the timescale of human existence, academic discussions and educational ideas do not necessarily match. There are also efforts to incorporate the perspective of environmental ethics into STEAM education. When seriously trying to incorporate ethical and philosophical perspectives into STEAM education, there are times when we think about the pros and cons of human survival. Although this material is effective in training critical thinking, it should be considered carefully, especially in the context of primary and secondary education.About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

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

Follow the IAU OAE on X and Facebook under @astro4edu
Detailed Design of a Deployable Tertiary Mirror for the Keck I Telescope
Creators: name: Prochaska, J. Xavier
name: Ratliff, Chris
name: Cabak, Jerry
name: Tripsas, Alex
name: Adkins, Sean
name: Bolte, Michael
name: Cowley, David
name: Dahler, Mike
name: Deich, Will
name: Lewis, Hilton
name: Nelson, Jerry
name: Park, Sam
name: Peck, Michael
name: Phillips, Drew
name: Pollard, Mike
name: Randolph, Bill
name: Sanford, Dale
name: Ward, Jim
name: Wold, Truman
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Motivated by the ever increasing pursuit of science with the transient sky (dubbed Time Domain Astronomy or TDA), we are fabricating and will commission a new deployable tertiary mirror for the Keck I telescope (K1DM3) at the W.M. Keck Observatory. This paper presents the detailed design of K1DM3 with emphasis on the opto-mechanics. This project has presented several design challenges. Foremost are the competing requirements to avoid vignetting the light path when retracted against a sufficiently rigid system for high-precision and repeatable pointing. The design utilizes an actuated swing arm to retract the mirror or deploy it into a kinematic coupling. The K1DM3 project has also required the design and development of custom connections to provide power, communications, and compressed air to the system. This NSF-MRI funded project is planned to be commissioned in Spring 2017.
description: 22 pages; many figures; Published in SPIE
On dynamical low-rank integrators for matrix differential equations
Creators: name: Schrammer, Stefan
Publisher: name: Karlsruher Institut für Technologie (KIT)
Year: 2022
Subjects: dynamical low-rank approximation
dynamical low-rank integrators
matrix differential equations
numerical analysis
error analysis
time integration
second-order matrix differential equation

description: This thesis is concerned with dynamical low-rank integrators for matrix differential equations, typically stemming from space discretizations of partial differential equations. We first construct and analyze a dynamical low-rank integrator for second-order matrix differential equations, which is based on a Strang splitting and the projector-splitting integrator, a dynamical low-rank integrator for first-order matrix differential equations proposed by Lubich and Osedelets in 2014. For the analysis, we derive coupled recursive inequalities, where we express the global error of the scheme in terms of a time-discretization error and a low-rank error contribution. The first can be treated with Taylor series expansion of the exact solution. For the latter, we make use of an induction argument and the convergence result derived by Kieri, Lubich, and Walach in 2016 for the projector-splitting integrator. From the original method, several variants are derived which are tailored to, e.g., stiff or highly oscillatory second-order problems. After discussing details on the implementation of dynamical low-rank schemes, we turn towards rank-adaptivity. For the projector-splitting integrator we derive both a technique to realize changes in the approximation ranks efficiently and a heuristic to choose the rank appropriately over time. The core idea is to determine the rank such that the error of the low-rank approximation does not spoil the time-discretization error. Based on the rank-adaptive pendant of the projector-splitting integrator, rank-adaptive dynamical low-rank integrators for (stiff and non-stiff) first-order and second-order matrix differential equations are derived. The thesis is concluded with numerical experiments to confirm our theoretical findings.
Tests of quark-hadron duality in tau-decays
Creators: name: Dominguez, C. A.
name: Hernandez, L. A.
name: Schilcher, K.
name: Spiesberger, H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: An exhaustive number of QCD finite energy sum rules for $τ$-decay together with the latest updated ALEPH data is used to test the assumption of global duality. Typical checks are the absence of the dimension $d=2$ condensate, the equality of the gluon condensate extracted from vector or axial vector spectral functions, the Weinberg sum rules, the chiral condensates of dimensions $d=6$ and $d=8$, as well as the extraction of some low-energy parameters of chiral perturbation theory. Suitable pinched linear integration kernels are introduced in the sum rules in order to suppress potential quark-hadron duality violations and experimental errors. We find no compelling indications of duality violations in hadronic $τ$-decay in the kinematic region above $s\simeq2.2$ GeV$^{2}$ for these kernels.
description: Invited talk at the Workshop on Determination of the Fundamental Parameters in QCD. Mainz Institute of Theoretical Physics, Johannes Gutenberg University of Mainz
Astronomy for All Age Groups
Creators: name: Shylaja, B S
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Astronomy for All Age Groups

Presenter: B S Shylaja (Jawaharlal Nehru Planetarium Bengaluru, India)

 

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

In the digital era, effective science communication requires novel tools like infographics. They simplify complex concepts, making science, especially astronomy, accessible to broader audiences. This research emphasizes the use of infographics in advancing astronomy education in resource-limited regions like Iraq. The conversion of intricate data into visuals allows easy understanding, fosters self-paced learning, and engages larger audiences. Furthermore, their cost-efficient production provides a sustainable educational alternative for resource-constrained areas. Ultimately, infographics could significantly enhance scientific literacy in regions with limited astronomical resources, inviting more exploration of their impact across various scientific disciplines.About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

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

Follow the IAU OAE on X and Facebook under @astro4edu
Using Open Science To Determine Physical Properties of Near Earth Asteroids
Creators: name: Nath, Arushi
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Using Open Science To Determine Physical Properties of Near Earth Asteroids

Presenter: Arushi Nath (Founder MonitorMyPlanet.com, Canada)

 

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

The pace of discovery of near-earth asteroids outpaces current abilities to analyze them. Knowledge of an asteroid's physical properties is essential to deflect them. I have developed open-source algorithms for classrooms that combine images from robotic telescopes, open-data, and math to determine asteroids' size, rotation, and strength. I took observations of the Didymos binary asteroid, and my algorithm determined it to be 820m wide, with a 2.26-hour rotation period and rubble-pile strength. I measured a 35-minute decrease in the mutual orbital period after impact by the 2022 NASA DART Mission. External sources validated the findings. Every citizen scientist is now a planetary defender.  The project won the 2023 Youth Astronomy Award of the Royal Astronomical Society of Canada.

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

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

Follow the IAU OAE on X and Facebook under @astro4edu
eResearch BoF - Research Data Management service: a health check - Notes
Creators: name: Cho, Jacky Kwun Lun
name: Sefton, Peter
name: Toufexis, Katina
name: Burton, Nichola
name: Russell, Keith
Publisher: name: Zenodo
Year: 2020
Subjects: Research Data Management

description: Notes and discussion captured from participants during the BoF session on institutional priorities in managing and improving their research data management services.
Discriminating image textures with the multiscale two-dimensional complexity-entropy causality plane
Creators: name: Zunino, Luciano
name: Ribeiro, Haroldo V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: The aim of this paper is to further explore the usefulness of the two-dimensional complexity-entropy causality plane as a texture image descriptor. A multiscale generalization is introduced in order to distinguish between different roughness features of images at small and large spatial scales. Numerically generated two-dimensional structures are initially considered for illustrating basic concepts in a controlled framework. Then, more realistic situations are studied. Obtained results allow us to confirm that intrinsic spatial correlations of images are successfully unveiled by implementing this multiscale symbolic information-theory approach. Consequently, we conclude that the proposed representation space is a versatile and practical tool for identifying, characterizing and discriminating image textures.
description: Accepted for publication in Chaos, Solitons & Fractals
Thermodynamics of gravitational clustering phenomena: $N$-body self-gravitating gas on the sphere $\mathbb{S}^{3}\subset\mathbb{R}^{4}$
Creators: name: Tello-Ortiz, F.
name: Velazquez, L.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: This work is devoted to the thermodynamics of gravitational clustering, a collective phenomenon with a great relevance in the $N$-body cosmological problem. We study a classical self-gravitating gas of identical non-relativistic particles defined on the sphere $\mathbb{S}^{3}\subset \mathbb{R}^{4}$ by considering gravitational interaction that corresponds to this geometric space. The analysis is performed within microcanonical description of an isolated Hamiltonian system by combining continuum approximation and steepest descend method. According to numerical solution of resulting equations, the gravitational clustering can be associated with two microcanonical phase transitions. A first phase transition with a continuous character is associated with breakdown of $SO(4)$ symmetry of this model. The second one is the gravitational collapse, whose continuous or discontinuous character crucially depends on the regularization of short-range divergence of gravitation potential. We also derive the thermodynamic limit of this model system, the astrophysical counterpart of Gibbs-Duhem relation, the order parameters that characterize its phase transitions and the equation of state. Other interesting behavior is the existence of states with negative heat capacities, which appear when the effects of gravitation turn dominant for energies sufficiently low. Finally, we comment the relevance of some of these results in the study of astrophysical and cosmological situations. Special interest deserves the gravitational modification of the equation of state due to the local inhomogeneities of matter distribution. Although this feature is systematically neglected in studies about Universe expansion, the same one is able to mimic an effect that is attributed to the dark energy: a negative pressure.
description: To appear in J. Stat. Mech.: Theo. Exp