cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Data curation strategies to support responsible big social research and big social data reuse
Creators: name: Mannheimer, Sara
Publisher: name: Zenodo
Year: 2022

description: This lightning talk responds to the question: how can data curators support responsible use and reuse of big social data? Big social research repurposes existing data from online sources such as social media, blogs, or forums, with a goal of advancing knowledge of human behavior and social phenomena. Big social research also presents an array of challenges—for example, challenges relating to context, informed consent, privacy, and intellectual property. Partly because of these challenges, big social data are less commonly shared in data repositories than other types of data, and they are on the periphery of data sharing and data reuse conversations. This talk presents the results of a study that aims to understand the data curation implications of big social research. The study identifies key challenges and strategies for responsible research practice and data curation through a review of the literature and interviews with curators and researchers. A key takeaway from the study is that we are in need of more concrete guidance for big social research. Institutional review boards, which act as the main compliance bodies in the United States, grant exempt status to most research involving secondary analysis, data reuse, or data scraping. Interviewees often reported cobbling together strategies for responsible practice from many sources—weighing benefits and risks in their own minds, talking to colleagues and collaborators, reading other studies, and implementing strategies they learned in graduate school. It was rare for interviewees to discuss standardized ethical guidelines or clear community best practices. The talk concludes with implications for data curation practice. For example, this study shows that data curation strategies such as metadata and description can communicate context and data quality to future users, and standardized metadata and file formats can support data aggregation and comparability. Data curators can also support big social research and big social data reuse by considering how informed consent and privacy were addressed by the social media platform and the research design. If data curators can reach researchers early in the research process, they can support sharing and reuse by advising on a variety of challenges during the research design phase. Data repositories can also be designed to support big social data reuse by providing analysis tools that do not require sharing the full big social dataset. Ultimately, this lightning talk provides strategies for data curators to support responsible use and sharing for big social data. Supporting responsible practices for using these data can help scale up social science research, thus enhancing our understanding of human behavior and social phenomena.
Barjols, arrivée des cars place de la Rouguière
Creators: name: Musée National Des Arts Et Traditions Populaires (Paris)
name: Centre D'ethnologie Française
Publisher: name: École des Hautes Études en Sciences Sociales; Institut  interdisciplinaire d'anthropologie du contemporain (Paris); Laboratoire d'anthropologie et d'histoire de l'institution de la culture (Paris)
Year: 2024

Abstract
Drop-on-coilable-fibre systems exhibit negative stiffness events and transitions in coiling morphology
Creators: name: Elettro, Hervé
name: Neukirch, Sébastien
name: Vollrath, Fritz
name: Antkowiak, Arnaud
Publisher: name: arXiv
Year: 2017
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We investigate the mechanics of elastic fibres carrying liquid droplets. In such systems, buckling may localize inside the drop cavity if the fibre is thin enough. This so-called drop-on-coilable-fibre system exhibits a surprising liquid-like response under compression, and a solid-like response under tension. Here we analyze this unconventional behavior in further details and find theoretical, numerical and experimental evidences of negative stiffness events. We find that the first and main negative stiffness regime owes its existence to the transfer of capillary-stored energy into mechanical curvature energy. The following negative stiffness events are associated with changes in the coiling morphology of the fibre. Eventually coiling becomes tightly locked into an ordered phase where liquid and solid deformations coexist.
description: 8 pages, 10 figures
Project Summary: Sea ice research in the Deep South Challenge
Creators: name: Deep South Challenge
Publisher: name: NIWA-hosted NSCs: Deep South and Sustainable Seas National Science Challenges
Year: 2024
Subjects: classificationCode: 370803
subject: Physical oceanography
classificationCode: 370902
subject: Glaciology
classificationCode: 379901
subject: Earth system sciences
classificationCode: 379999
subject: Other earth sciences not elsewhere classified
classificationCode: 519999
subject: Other physical sciences not elsewhere classified

description: The Deep South National Science challenge has funded both sea ice observational research (Targeted Observation and Process-Informed Modelling of Antarctic Sea Ice (TOPIMASI)) and climate modelling research over nine years of the Challenge. With the evolution of this research, this programme has produced improvements to climate models, such as the physical core of the New Zealand Earth System Model (NZESM), which have built on the observational sea ice research. This brief outlines the research that has been conducted through these programmes.
Recrudescence of massive fermion production by oscillons
Creators: name: Saffin, Paul M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this letter we bring together the physics of preheating, following a period of inflation, and the dynamics of non-topological solitons, namely oscillons. We show that the oscillating condensate that makes up an oscillon can be an efficient engine for producing heavy fermions, just as a homogeneous condensate is known for doing the same. This then allows heavy fermions to be produced when the energy scale of the Universe has dropped below the scale naturally associated to the fermions.
description: 6 pages, 2 figures. Included new data, and references. Version accepted for publication in JHEP
Predicting facial eczema (FE) risks in a changing New Zealand climate
Creators: name: Deep South Challenge
Publisher: name: NIWA-hosted NSCs: Deep South and Sustainable Seas National Science Challenges
Year: 2024
Subjects: classificationCode: 300206
subject: Agricultural spatial analysis and modelling
classificationCode: 410402
subject: Environmental assessment and monitoring

description: This document is a brief that can be used by government, industry, and rural professionals as it provides valuable information on the effects climate change and rising temperatures have on livestock and the risk of developing facial eczema. This document summarises the research by AgResearch for Our Land and Water and Deep South.
The time-dependent spectrum of a single photon and its POVM
Creators: name: van Enk, S. J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Suppose we measure the time-dependent spectrum of a single photon. That is, we first send the photon through a set of frequency filters (which we assume to have different filter frequencies but the same finite bandwidth $Γ$), and then record at what time (with some finite precision $Δt$, and with some finite efficiency $η$) and after passing what filter the photon is detected. What is the POVM (Positive-Operator Valued Measure, the most general description of a quantum measurement) corresponding to such a measurement? We show how to construct the POVM in various cases, with special interest in the case $ΓΔt\ll 1$ (time-frequency uncertainty still holds, even in that limit). One application of the formalism is to heralding single photons. We also find a Hong-Ou-Mandel type of interference effect with two photons entering a frequency filter.
description: expanded version, 8 pages
A Novel Hybrid Quicksort Algorithm Vectorized using AVX-512 on Intel Skylake
Creators: name: Bramas, Berenger
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Software (cs.MS)
subject: FOS: Computer and information sciences

description: The modern CPU's design, which is composed of hierarchical memory and SIMD/vectorization capability, governs the potential for algorithms to be transformed into efficient implementations. The release of the AVX-512 changed things radically, and motivated us to search for an efficient sorting algorithm that can take advantage of it. In this paper, we describe the best strategy we have found, which is a novel two parts hybrid sort, based on the well-known Quicksort algorithm. The central partitioning operation is performed by a new algorithm, and small partitions/arrays are sorted using a branch-free Bitonic-based sort. This study is also an illustration of how classical algorithms can be adapted and enhanced by the AVX-512 extension. We evaluate the performance of our approach on a modern Intel Xeon Skylake and assess the different layers of our implementation by sorting/partitioning integers, double floating-point numbers, and key/value pairs of integers. Our results demonstrate that our approach is faster than two libraries of reference: the GNU \emph{C++} sort algorithm by a speedup factor of 4, and the Intel IPP library by a speedup factor of 1.4.
description: 8 pages, research paper
Climate change impacts on erosion and sediment loads in New Zealand
Creators: name: Deep South Challenge
Publisher: name: NIWA-hosted NSCs: Deep South and Sustainable Seas National Science Challenges
Year: 2024
Subjects: classificationCode: 300206
subject: Agricultural spatial analysis and modelling
classificationCode: 410402
subject: Environmental assessment and monitoring

description: This research explores how climate change will impact sediment loads in our rivers through modelling changes to surficial erosion, mass movement and streambank erosion. The framework takes the impact of divergent future trajectories for mean annual rainfall (MAR), storm magnitude-frequency, and mean annual flood (MAF) to be expressed in future sediment loads through distinct changes in surficial, mass movement, and streambank erosion.

This info sheet is for those interested in the future implications of climate change on erosion and sediment loads in New Zealand: policymakers, catchment managers, farmers and landowners who rely on data for informed decision making.
Numerical Multi-Loop Calculations via Finite Integrals and One-Mass EW-QCD Drell-Yan Master Integrals
Creators: name: von Manteuffel, Andreas
name: Schabinger, Robert M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study a recently-proposed approach to the numerical evaluation of multi-loop Feynman integrals using available sector decomposition programs. As our main example, we consider the two-loop integrals for the $αα_s$ corrections to Drell-Yan lepton production with up to one massive vector boson in physical kinematics. As a reference, we evaluate these planar and non-planar integrals by the method of differential equations through to weight five. Choosing a basis of finite integrals for the numerical evaluation with SecDec3 leads to tremendous performance improvements and renders the otherwise problematic seven-line topologies numerically accessible. As another example, basis integrals for massless QCD three loop form factors are evaluated with FIESTA4. Here, employing a basis of finite integrals results in an overall speedup of more than an order of magnitude.
description: 24 pages, 1 figure, 4 tables, 2 ancillary files with analytical results; in v2: minor improvements in the text with additional references added. v2 is the version published in JHEP
Unimodal Gorenstein h-vectors without the Stanley-Iarrobino property
Creators: name: Migliore, Juan
name: Zanello, Fabrizio
Publisher: name: arXiv
Year: 2016
Subjects: subject: Commutative Algebra (math.AC)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: Primary: 13D40, Secondary: 13H10, 13E10, 05E40

description: The study of the $h$-vectors of graded Gorenstein algebras is an important topic in combinatorial commutative algebra, which despite the large amount of literature produced during the last several years, still presents many interesting open questions. In this note, we commence a study of those unimodal Gorenstein $h$-vectors that do \emph{not} satisfy the Stanley-Iarrobino property. Our main results, which are characteristic free, show that such $h$-vectors exist: 1) In socle degree $e$ if and only if $e\ge 6$; and 2) In every codimension five or greater. The main case that remains open is that of codimension four, where no Gorenstein $h$-vector is known without the Stanley-Iarrobino property. We conclude by proposing the following very general conjecture: The existence of any arbitrary level $h$-vector is \emph{independent} of the characteristic of the base field.
description: A few minor revisions. Final version to appear in Comm. Algebra
Privacy-enhancing Aggregation of Internet of Things Data via Sensors Grouping
Creators: name: Bennati, Stefano
name: Pournaras, Evangelos
Publisher: name: arXiv
Year: 2017
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: Big data collection practices using Internet of Things (IoT) pervasive technologies are often privacy-intrusive and result in surveillance, profiling, and discriminatory actions over citizens that in turn undermine the participation of citizens to the development of sustainable smart cities. Nevertheless, real-time data analytics and aggregate information from IoT devices open up tremendous opportunities for managing smart city infrastructures. The privacy-enhancing aggregation of distributed sensor data, such as residential energy consumption or traffic information, is the research focus of this paper. Citizens have the option to choose their privacy level by reducing the quality of the shared data at a cost of a lower accuracy in data analytics services. A baseline scenario is considered in which IoT sensor data are shared directly with an untrustworthy central aggregator. A grouping mechanism is introduced that improves privacy by sharing data aggregated first at a group level compared as opposed to sharing data directly to the central aggregator. Group-level aggregation obfuscates sensor data of individuals, in a similar fashion as differential privacy and homomorphic encryption schemes, thus inference of privacy-sensitive information from single sensors becomes computationally harder compared to the baseline scenario. The proposed system is evaluated using real-world data from two smart city pilot projects. Privacy under grouping increases, while preserving the accuracy of the baseline scenario. Intra-group influences of privacy by one group member on the other ones are measured and fairness on privacy is found to be maximized between group members with similar privacy choices. Several grouping strategies are compared. Grouping by proximity of privacy choices provides the highest privacy gains. The implications of the strategy on the design of incentives mechanisms are discussed.
"A Model Repository" Showcasing a Collection of Architectural Models for Digital Discovery and Reuse
Creators: name: Ayres, William
Publisher: name: Zenodo
Year: 2022
Subjects: subject: IDCC22
subject: IDCC2022
subject: Figshare
subject: Architecture
subject: FOS: Civil engineering
subject: Model
subject: Archive
subject: Discovery
subject: Reuse
subject: B.15Workshop

description: This presentation was delivered by the author as an online Lightning Talk on 14 June 2022, as part of the main programme for IDCC22, the 17th International Digital Curation Conference. The talk focuses on a project to catalogue and digitise a large collection of architectural models held in storage by the Manchester School of Architecture's B.15 Modelmaking Workshop. The intention is to make these available as digital resources for discovery, research and reuse by a wider audience, and to provide a showcase for the models in the University of Manchester's Figshare for Institutions research data repository. This project is being supported and delivered as part of the University's ongoing Research Lifecycle Programme (RLP).
Changes in maize growth with climate change
Creators: name: Deep South Challenge
Publisher: name: NIWA-hosted NSCs: Deep South and Sustainable Seas National Science Challenges
Year: 2024
Subjects: classificationCode: 300206
subject: Agricultural spatial analysis and modelling
classificationCode: 410402
subject: Environmental assessment and monitoring

description: This infosheet is for those interested in the impacts of climate change on maize growth. The data can inform farmers and crop managers on potential future growth trends of maize grain under climate change.
An Approach for Curating Collections of Historical Documents with the Use of Topic Detection Technologies
Creators: name: Andresel, Medina
name: Gordea, Sergiu
name: Stevanetic, Srdjan
name: Schütz, Mina
Publisher: name: Zenodo
Year: 2022
Subjects: Digital Curation
Topic Detection
Natural Language Processing
Transcribathon

description: Presentation for IDCC 2022 Conference related to the paper published in International Journal of Digital Curation https://doi.org/10.2218/ijdc.v17i1.819
Stability of Anisotropic Stellar Filaments
Creators: name: Bhatti, M. Zaeem-ul-Haq
name: Yousaf, Z.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: The study of perturbation of self-gravitating celestial cylindrical object have been carried out in this paper. We have designed a framework to construct the collapse equation by formulating the modified field equations with the background of $f(R,T)$ theory as well as dynamical equations from the contracted form of Bianchi identities with anisotropic matter configuration. We have encapsulated the radial perturbations on metric and material variables of the geometry with some known static profile at Newtonian and post-Newtonian regimes. We examined a strong dependence of unstable regions on stiffness parameter which measures the rigidity of the fluid. Also, the static profile and matter variables with $f(R,T)$ dark source terms control the instability of compact cylindrical system.
Partition functions and a generalized coloring-flow duality for embedded graphs
Creators: name: Litjens, Bart
name: Sevenster, Bart
Publisher: name: arXiv
Year: 2017
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C10, 05C15, 05C21, 20C15, 57M10

description: Let $G$ be a finite group and $χ: G \rightarrow \mathbb{C}$ a class function. Let $H = (V,E)$ be a directed graph with for each vertex a cyclic order of the edges incident to it. The cyclic orders give a collection $F$ of faces of $H$. Define the partition function $P_χ(H) := \sum_{κ: E \rightarrow G}\prod_{v \in V}χ(κ(δ(v)))$, where $κ(δ(v))$ denotes the product of the $κ$-values of the edges incident with $v$ (in order), where the inverse is taken for any edge leaving $v$. Write $χ= \sum_λm_λχ_λ$, where the sum runs over irreducible representations $λ$ of $G$ with character $χ_λ$ and with $m_λ \in \mathbb{C}$ for every $λ$. If $H$ is connected, it is proved that $P_χ(H) = |G|^{|E|}\sum_λχ_λ(1)^{|F|-|E|}m_λ^{|V|}$, where $1$ is the identity element of $G$. Among the corollaries, a formula for the number of nowhere-identity $G$-flows on $H$ is derived, generalizing a result of Tutte. We show that these flows correspond bijectively to certain proper $G$-colorings of a covering graph of the dual graph of $H$. This correspondence generalizes coloring-flow duality for planar graphs.
description: Based on comments of the referees, some revisions have been made. 13 pages. To appear in Journal of Graph Theory
Qudit-Basis Universal Quantum Computation using $χ^{(2)}$ Interactions
Creators: name: Niu, Murphy Yuezhen
name: Chuang, Isaac L.
name: Shapiro, Jeffrey H.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We prove that universal quantum computation can be realized---using only linear optics and $χ^{(2)}$ (three-wave mixing) interactions---in any $(n+1)$-dimensional qudit basis of the $n$-pump-photon subspace. First, we exhibit a strictly universal gate set for the qubit basis in the one-pump-photon subspace. Next, we demonstrate qutrit-basis universality by proving that $χ^{(2)}$ Hamiltonians and photon-number operators generate the full $\mathfrak{u}(3)$ Lie algebra in the two-pump-photon subspace, and showing how the qutrit controlled-$Z$ gate can be implemented with only linear optics and $χ^{(2)}$ interactions. We then use proof by induction to obtain our general qudit result. Our induction proof relies on coherent photon injection/subtraction, a technique enabled by $χ^{(2)}$ interaction between the encoding modes and ancillary modes. Finally, we show that coherent photon injection is more than a conceptual tool in that it offers a route to preparing high-photon-number Fock states from single-photon Fock states.
description: 9 pages, 3 figures
Clockwork Goldstone Bosons
Creators: name: Ahmed, Aqeel
name: Dillon, Barry M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The clockwork mechanism has recently been proposed as a natural way to generate hierarchies among parameters in quantum field theories. The mechanism is characterized by a very specific pattern of spontaneous and explicit symmetry breaking, and the presence of new light states referred to as `gears'. In this paper we begin by investigating the self-interactions of these gears in a scalar clockwork model and find a parity-like selection rule at all orders in the fields. We then proceed to investigate how the clockwork mechanism can be realized in 5D linear dilaton models from the spontaneous symmetry breaking of a complex bulk scalar field. We also discuss how the clockwork mechanism is manifest in the scalar components of 5D gauge theories in the linear dilaton model, and build their 4D deconstructed analogue. Finally we discuss attempts at building both 4D and 5D realizations of a non-abelian scalar clockwork mechanism, where in the latter we consider scenarios in which the Goldstone bosons arise from 5D scalar and 5D gauge fields.
description: 32 pages, 1 figure, v4: title changed, a new approach is introduced to clockwork mechanism for the abelian and non-abelian clockwork models with the perspective of 5D gauge theories in the linear dilaton geometry
Y-Calculus: A Language for Real Matrices Derived from the ZX-Calculus
Creators: name: Jeandel, Emmanuel
name: Perdrix, Simon
name: Vilmart, Renaud
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Logic in Computer Science (cs.LO)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: We introduce a ZX-like diagrammatic language devoted to manipulating real matrices - and rebits -, with its own set of axioms. We prove the necessity of some non trivial axioms of these. We show that some restriction of the language is complete. We exhibit two interpretations to and from the ZX-Calculus, thus showing the consistency between the two languages. Finally, we derive from our work a way to extract the real or imaginary part of a ZX-diagram, and prove that a restriction of our language is complete if the equivalent restriction of the ZX-calculus is complete.
description: In Proceedings QPL 2017, arXiv:1802.09737
Characterization of a Deuterium-Deuterium Plasma Fusion Neutron Generator
Creators: name: Lang, R. F.
name: Pienaar, J.
name: Hogenbirk, E.
name: Masson, D.
name: Nolte, R.
name: Zimbal, A
name: Röttger, S.
name: Benabderrahmane, M. L.
name: Bruno, G
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We characterize the neutron output of a deuterium-deuterium plasma fusion neutron generator, model 35-DD-W-S, manufactured by NSD/Gradel-Fusion. The measured energy spectrum is found to be dominated by neutron peaks at 2.2 MeV and 2.7 MeV. A detailed GEANT4 simulation accurately reproduces the measured energy spectrum and confirms our understanding of the fusion process in this generator. Additionally, a contribution of 14.1 MeV neutrons from deuterium-tritium fusion is found at a level of~$3.5\%$, from tritium produced in previous deuterium-deuterium reactions. We have measured both the absolute neutron flux as well as its relative variation on the operational parameters of the generator. We find the flux to be proportional to voltage $V^{3.32 \pm 0.14}$ and current $I^{0.97 \pm 0.01}$. Further, we have measured the angular dependence of the neutron emission with respect to the polar angle. We conclude that it is well described by isotropic production of neutrons within the cathode field cage.
description: 10 pages, 9 figures
Exploring Halo Substructure with Giant Stars. XV. Discovery of a Connection between the Monoceros Ring and the Triangulum-Andromeda Overdensity?
Creators: name: Li, Ting S.
name: Sheffield, Allyson A.
name: Johnston, Kathryn V.
name: Marshall, Jennifer L.
name: Majewski, Steven R.
name: Price-Whelan, Adrian M.
name: Damke, Guillermo J.
name: Beaton, Rachael L.
name: Bernard, Edouard J.
name: Richardson, Whitney
name: Sharma, Sanjib
name: Sesar, Branimir
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Thanks to modern sky surveys, over twenty stellar streams and overdensity structures have been discovered in the halo of the Milky Way. In this paper, we present an analysis of spectroscopic observations of individual stars from one such structure, "A13", first identified as an overdensity using the M giant catalog from the Two Micron All-Sky Survey. Our spectroscopic observations show that stars identified with A13 have a velocity dispersion of $\lesssim$ 40 $\mathrm{km~s^{-1}}$, implying that it is a genuine coherent structure rather than a chance super-position of random halo stars. From its position on the sky, distance ($\sim$15~kpc heliocentric), and kinematical properties, A13 is likely to be an extension of another low Galactic latitude substructure -- the Galactic Anticenter Stellar Structure (also known as the Monoceros Ring) -- towards smaller Galactic longitude and farther distance. Furthermore, the kinematics of A13 also connect it with another structure in the southern Galactic hemisphere -- the Triangulum-Andromeda overdensity. We discuss these three connected structures within the context of a previously proposed scenario that one or all of these features originate from the disk of the Milky Way.
description: 12 pages, 9 figures. Accepted for publication in ApJ
Second law of thermodynamics with quantum memory
Creators: name: Ren, Li-Hang
name: Fan, Heng
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We design a heat engine with multi-heat-reservoir, ancillary system and quantum memory. We then derive an inequality related with the second law of thermodynamics, and give a new limitation about the work gain from the engine by analyzing the entropy change and quantum mutual information change during the process. In addition and remarkably, by combination of two independent engines and with the help of the entropic uncertainty relation with quantum memory, we find that the total maximum work gained from those two heat engines should be larger than a quantity related with quantum entanglement between the ancillary state and the quantum memory. This result provides a lower bound for the maximum work extracted, in contrast with the upper bound in the conventional second law of thermodynamics. However, the validity of this inequality depends on whether the maximum work can achieve the upper bound.
description: 6 pages
Covariant quantizations in plane and curved spaces
Creators: name: Assirati, J.
name: Gitman, D. M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present covariant quantization rules for nonsingular finite dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function $ω(θ)$, $θ\in\left( 1,0\right)$, which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function $ω\left( θ\right)$. Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one $ω(θ)$ and by an additional function $Θ\left( x,ξ\right)$. The above mentioned minimal family is a part at $Θ=1$ of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in Polar coordinates, we directly obtain a correct result.
description: 38 pages, 2 figures, version published in The European Physical Journal C
A Structural and Nominal Syntax for Diagrams
Creators: name: Ghica, Dan R
name: Lopez, Aliaume
Publisher: name: arXiv
Year: 2017
Subjects: subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences

description: The correspondence between monoidal categories and graphical languages of diagrams has been studied extensively, leading to applications in quantum computing and communication, systems theory, circuit design and more. From the categorical perspective, diagrams can be specified using (name-free) combinators which enjoy elegant equational properties. However, conventional notations for diagrammatic structures, such as hardware description languages (VHDL, Verilog) or graph languages (Dot), use a different style, which is flat, relational, and reliant on extensive use of names (labels). Such languages are not known to enjoy nice syntactic equational properties. However, since they make it relatively easy to specify (and modify) arbitrary diagrammatic structures they are more popular than the combinator style. In this paper we show how the two approaches to diagram syntax can be reconciled and unified in a way that does not change the semantics and the existing equational theory. Additionally, we give sound and complete equational theories for the combined syntax.
description: In Proceedings QPL 2017, arXiv:1802.09737
Three-phase Interstellar medium in Galaxies Resolving Evolution with Star formation and Supernova feedback (TIGRESS): Algorithms, Fiducial model, and Convergence
Creators: name: Kim, Chang-Goo
name: Ostriker, Eve C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We introduce TIGRESS, a novel framework for multi-physics numerical simulations of the star-forming interstellar medium (ISM) implemented in the Athena MHD code. The algorithms of TIGRESS are designed to spatially and temporally resolve key physical features, including: (1) the gravitational collapse and ongoing accretion of gas that leads to star formation in clusters, (2) the explosions of supernovae (SNe) both near their progenitor birth sites and from runaway OB stars, with time delays relative to star formation determined by population synthesis, (3) explicit evolution of SN remnants prior to the onset of cooling, which leads to the creation of the hot ISM, (4) photoelectric heating of the warm and cold phases of the ISM that tracks the time-dependent ambient FUV field from the young cluster population, (5) large-scale galactic differential rotation, which leads to epicyclic motion and shears out overdense structures, limiting large-scale gravitational collapse, (6) accurate evolution of magnetic fields, which can be important for vertical support of the ISM disk as well as angular momentum transport. We present tests of the newly-implemented physics modules, and demonstrate application of TIGRESS in a fiducial model representing the Solar neighborhood environment. We use a resolution study to demonstrate convergence and evaluate the minimum resolution dx required to correctly recover several ISM properties, including the star formation rate, wind mass-loss rate, disk scale height, turbulent and Alfvenic velocity dispersions, and volume fractions of warm and hot phases. For the Solar neighborhood model, all these ISM properties are converged at dx <= 8pc.
description: ApJ accepted. Animation is available at http://www.astro.princeton.edu/~cgkim/astral/index.html#movie
Two-dimensional InSe as a potential thermoelectric material
Creators: name: Hung, Nguyen T.
name: Nugraha, Ahmad R. T.
name: Saito, R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Thermoelectric properties of monolayer indium selenide (InSe) are investigated by using Boltzman transport theory and first-principles calculations as a function of Fermi energy and crystal orientation. We find that the maximum power factor of p-type (n-type) monolayer InSe can be as large as 0.049 (0.043) W/K$^2$m at 300 K in the armchair direction. The excellent thermoelectric performance of monolayer InSe is attributed to both of its Seebeck coefficient and electrical conductivity. The large Seebeck coefficient originates from the moderate (about 2 eV) band gap of monolayer InSe as an indirect gap semiconductor, while its large electrical conductivity is due to its unique two-dimensional density of states (DOS), which consists of an almost constant DOS near the conduction band bottom and a sharp peak near the valence band top.
description: 5 pages, 2 figures, some typos have been corrected
As NZ gets serious about climate change, can electricity replace fossil fuels in time?
Creators: name: Purdie, J.
Publisher: name: NIWA-hosted NSCs: Deep South and Sustainable Seas National Science Challenges
Year: 2024
Subjects: classificationCode: 370704
subject: Surface water hydrology
classificationCode: 410103
subject: Human impacts of climate change and human adaptation

description: As fossil fuels are phased out over the coming decades, the Climate Change Commission (CCC) suggests electricity will take up much of the slack, powering our vehicle fleet and replacing coal and gas in industrial processes. But can the electricity system really provide for this increased load where and when it is needed? The answer is “yes”, with some caveats.

Article published in The Conversation by Deep South researcher Jen Purdie for the Climate Change Impacts on NZ Electricity project.
Perpendicular diffusion coefficient of cosmic rays in the presence of weak adiabatic focusing
Creators: name: Wang, J. F.
name: Qin, G.
name: Ma, Q. M.
name: Song, T.
name: Yuan, S. B.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The influence of adiabatic focusing on particle diffusion is an important topic in astrophysics and plasma physics. In the past several authors have explored the influence of along-field adiabatic focusing on parallel diffusion of charged energetic particles. In this paper by using the Unified NonLinear Transport (UNLT) theory developed by Shalchi (SH2010) and the method of He and Schlickeiser (HS2014) we derive a new nonlinear perpendicular diffusion coefficient for non-uniform background magnetic field. This formula demonstrates that particle perpendicular diffusion coefficient is modified by along-field adiabatic focusing. For isotropic pitch-angle scattering and weak adiabatic focusing limit the derived perpendicular diffusion coefficient is independent of the sign of adiabatic focusing characteristic length. For two-component model we simplify the perpendicular diffusion coefficient up to second order of the power series of adiabatic focusing characteristic quantity. We find that the first order modifying factor is equal to zero and the sign of the second one is determined by the energy of particles.
Adversarial Inverse Graphics Networks: Learning 2D-to-3D Lifting and Image-to-Image Translation from Unpaired Supervision
Creators: name: Tung, Hsiao-Yu Fish
name: Harley, Adam W.
name: Seto, William
name: Fragkiadaki, Katerina
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Researchers have developed excellent feed-forward models that learn to map images to desired outputs, such as to the images' latent factors, or to other images, using supervised learning. Learning such mappings from unlabelled data, or improving upon supervised models by exploiting unlabelled data, remains elusive. We argue that there are two important parts to learning without annotations: (i) matching the predictions to the input observations, and (ii) matching the predictions to known priors. We propose Adversarial Inverse Graphics networks (AIGNs): weakly supervised neural network models that combine feedback from rendering their predictions, with distribution matching between their predictions and a collection of ground-truth factors. We apply AIGNs to 3D human pose estimation and 3D structure and egomotion estimation, and outperform models supervised by only paired annotations. We further apply AIGNs to facial image transformation using super-resolution and inpainting renderers, while deliberately adding biases in the ground-truth datasets. Our model seamlessly incorporates such biases, rendering input faces towards young, old, feminine, masculine or Tom Cruise-like equivalents (depending on the chosen bias), or adding lip and nose augmentations while inpainting concealed lips and noses.
Knotted surfaces in 4-manifolds by Knot surgery and Stabilization
Creators: name: Kim, Hee Jung
Publisher: name: arXiv
Year: 2017
Subjects: subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 57M25, 57Q60

description: Given a simply-connected closed 4-manifold $X$ and a smoothly embedded oriented surface $Σ$, various constructions based on Fintushel-Stern knot surgery have produced new surfaces in $X$ that are pairwise homeomorphic to $Σ$, but not diffeomorphic. We prove that for all known examples of surface knots constructed from knot surgery operations that preserve the fundamental group of the complement of surface knots, they become pairwise diffeomorphic after stabilizing by connected summing with one $S^2\tilde{\times}S^2$. When $X$ is spin, we show in addition that any surfaces obtained by a knot surgery whose complements have cyclic fundamental group become pairwise diffeomorphic after one stabilization by $S^2\tilde{\times}S^2$.
description: 20 pages, 10 figures; to appear in Transactions of the American Mathematical Society
Upper-limit on the Advanced Virgo output mode cleaner cavity length noise
Creators: name: Bonnand, R
name: Ducrot, M
name: Gouaty, R
name: Marion, F
name: Masserot, A
name: Mours, B
name: Pacaud, E
name: Rolland, L
name: Was, M
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The Advanced Virgo detector uses two monolithic optical cavities at its output port to suppress higher order modes and radio frequency sidebands from the carrier light used for gravitational wave detection. These two cavities in series form the output mode cleaner. We present a measured upper limit on the length noise of these cavities that is consistent with the thermo-refractive noise prediction of $8 \times 10^{-16}\,\textrm{m/Hz}^{1/2}$ at 15 Hz. The cavity length is controlled using Peltier cells and piezo-electric actuators to maintain resonance on the incoming light. A length lock precision of $3.5 \times 10^{-13}\,\textrm{m}$ is achieved. These two results are combined to demonstrate that the broadband length noise of the output mode cleaner in the 10-60 Hz band is at least a factor 10 below other expected noise sources in the Advanced Virgo detector design configuration.
description: 10 pages, 4 figures, accepted by CQG
Dimer geometry, amoebae and a vortex dimer model
Creators: name: Nash, Charles
name: O'Connor, Denjoe
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Lattice (hep-lat)
subject: Mathematical Physics (math-ph)
subject: Algebraic Geometry (math.AG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We present a geometrical approach for studying dimers. We introduce a connection for dimer problems on bipartite and non-bipartite graphs. In the bipartite case the connection is flat but has non-trivial ${\bf Z}_2$ holonomy round certain curves. This holonomy has the universality property that it does not change as the number of vertices in the fundamental domain of the graph is increased. It is argued that the K-theory of the torus, with or without punctures, is the appropriate underlying invariant. In the non-bipartite case the connection has non-zero curvature as well as non-zero Chern number. The curvature does not require the introduction of a magnetic field. The phase diagram of these models is captured by what is known as an amoeba. We introduce a dimer model with negative edge weights that give rise to vortices. The amoebae for various models are studied with particular emphasis on the case of negative edge weights which corresponds to the presence of vortices. Vortices gives rise to new kinds of amoebae with certain singular structures which we investigate. On the amoeba of the vortex full hexagonal lattice we find the partition function corresponds to that of a massless Dirac doublet.
description: 25 pages, 9 figures Latest version: some references added and typos removed
Global Optimality in Low-rank Matrix Optimization
Creators: name: Zhu, Zhihui
name: Li, Qiuwei
name: Tang, Gongguo
name: Wakin, Michael B.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: Optimization and Control (math.OC)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: This paper considers the minimization of a general objective function $f(X)$ over the set of rectangular $n\times m$ matrices that have rank at most $r$. To reduce the computational burden, we factorize the variable $X$ into a product of two smaller matrices and optimize over these two matrices instead of $X$. Despite the resulting nonconvexity, recent studies in matrix completion and sensing have shown that the factored problem has no spurious local minima and obeys the so-called strict saddle property (the function has a directional negative curvature at all critical points but local minima). We analyze the global geometry for a general and yet well-conditioned objective function $f(X)$ whose restricted strong convexity and restricted strong smoothness constants are comparable. In particular, we show that the reformulated objective function has no spurious local minima and obeys the strict saddle property. These geometric properties imply that a number of iterative optimization algorithms (such as gradient descent) can provably solve the factored problem with global convergence.
Accelerated Computing in Magnetic Resonance Imaging -- Real-Time Imaging Using Non-Linear Inverse Reconstruction
Creators: name: Schaetz, Sebastian
name: Voit, Dirk
name: Frahm, Jens
name: Uecker, Martin
Publisher: name: arXiv
Year: 2017
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Medical Physics (physics.med-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Purpose: To develop generic optimization strategies for image reconstruction using graphical processing units (GPUs) in magnetic resonance imaging (MRI) and to exemplarily report about our experience with a highly accelerated implementation of the non-linear inversion algorithm (NLINV) for dynamic MRI with high frame rates. Methods: The NLINV algorithm is optimized and ported to run on an a multi-GPU single-node server. The algorithm is mapped to multiple GPUs by decomposing the data domain along the channel dimension. Furthermore, the algorithm is decomposed along the temporal domain by relaxing a temporal regularization constraint, allowing the algorithm to work on multiple frames in parallel. Finally, an autotuning method is presented that is capable of combining different decomposition variants to achieve optimal algorithm performance in different imaging scenarios. Results: The algorithm is successfully ported to a multi-GPU system and allows online image reconstruction with high frame rates. Real-time reconstruction with low latency and frame rates up to 30 frames per second is demonstrated. Conclusion: Novel parallel decomposition methods are presented which are applicable to many iterative algorithms for dynamic MRI. Using these methods to parallelize the NLINV algorithm on multiple GPUs it is possible to achieve online image reconstruction with high frame rates.
description: 22 pages, 8 figures, 6 tables
Analysis of NuSTAR and Suzaku observations of Cyg X-1 in the hard state: evidence for a truncated disc geometry
Creators: name: Basak, Rupal
name: Zdziarski, Andrzej A.
name: Parker, Michael
name: Islam, Nazma
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The geometry of the accretion flow in black-hole X-ray binaries in the hard state, in particular the position of the disc inner edge, has been a subject of intense debate in recent years. We address this issue by performing a spectral study of simultaneous observations of Cyg X-1 in the hard state by NuSTAR and Suzaku. The same data were analysed before, and modelled by a lamppost containing hybrid electrons and located very close to the horizon, which emission was incident on a surrounding disc extending almost to the innermost stable circular orbit. We re-analyse the incident continuum model and show that it suffers from the lack of physical self-consistency. Still, the good fit to the data provided by this model indicates that the real continuum has a similar shape. We find it features a strong soft X-ray excess below a few keV, which we model as a soft thermal-Comptonization component, in addition to the main hard thermal-Compton component. This continuum model with reflection of both components yields the overall lowest $χ^2$ and has a geometry with a hot inner accretion flow and a disc truncated at $\simeq$13--20 gravitational radii. On the other hand, we have also found spectral solution with a lamppost at a large height and a disc that can extend to the innnermost stable circular orbit, though somewhat statistically worse. Overall, we find the fitted truncation radius depends on the assumed continuum and geometry.
description: MNRAS, in press