cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Rough sound waves in $3D$ compressible Euler flow with vorticity
Creators: name: Disconzi, Marcelo M.
name: Luo, Chenyun
name: Mazzone, Giusy
name: Speck, Jared
Publisher: name: arXiv
Year: 2019
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: Primary: 35Q31, Secondary: 35Q35, 35L10, 35L67

description: We prove a series of results tied to the regularity and geometry of solutions to the $3D$ compressible Euler equations with vorticity and entropy. Our framework exploits and reveals additional virtues of a recent new formulation of the equations, which decomposed the flow into a geometric "(sound) wave-part" coupled to a "transport-div-curl-part" (transport-part for short), with both parts exhibiting remarkable properties. Our main result is that the time of existence can be controlled in terms of the $H^{2^+}(\mathbb{R}^3)$-norm of the wave-part of the initial data and various Sobolev and Hölder norms of the transport-part of the initial data, the latter comprising the initial vorticity and entropy. The wave-part regularity assumptions are optimal in the scale of Sobolev spaces: shocks can instantly form if one only assumes a bound for the $H^2(\mathbb{R}^3)$-norm of the wave-part of the initial data. Our proof relies on the assumption that the transport-part of the initial data is more regular than the wave-part, and we show that the additional regularity is propagated by the flow, even though the transport-part of the flow is deeply coupled to the rougher wave-part. To implement our approach, we derive several results of independent interest: i) sharp estimates for the acoustic geometry, i.e., the geometry of sound cones; ii) Strichartz estimates for quasilinear sound waves coupled to vorticity and entropy; and iii) Schauder estimates for the transport-div-curl-part. Compared to previous works on low regularity, the main new features of the paper are that the quasilinear PDE systems under study exhibit multiple speeds of propagation and that elliptic estimates for various components of the fluid are needed, both to avoid loss of regularity and to gain space-time integrability.
description: This version of our article closely matches the published version, which features some corrections and an abbreviated introduction compared to the first version we posted on arXiv.org on September 5, 2019. As in the published version, here we refer readers to the first arXiv version for an extended introduction that features some additional background material
Formation of shear-bands in drying colloidal dispersions
Creators: name: Kiatkirakajorn, Pree-Cha
name: Goehring, Lucas
Publisher: name: arXiv
Year: 2015
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: In directionally-dried colloidal dispersions regular bands can appear behind the drying front, inclined at $\pm45^\circ$ to the drying line. Although these features have been noted to share visual similarities to shear bands in metal, no physical mechanism for their formation has ever been suggested, until very recently. Here, through microscopy of silica and polystyrene dispersions, dried in Hele-Shaw cells, we demonstrate that the bands are indeed associated with local shear strains. We further show how the bands form, that they scale with the thickness of the drying layer, and that they are eliminated by the addition of salt to the drying dispersions. Finally, we reveal the origins of these bands in the compressive forces associated with drying, and show how they affect the optical properties (birefringence) of colloidal films and coatings.
description: 4 pages, 5 figures
(1183) Cuthbert Blundell
Creators: name: Professions, Victorian
Publisher: name: University of Oxford
Year: 2022
Subjects: subject: 220201 Business and Labour History
subject: FOS: Philosophy, ethics and religion
subject: History
subject: 140203 Economic History
subject: FOS: Economics and business

description: This three-year research project began in January 2014 and investigated whether, during the Victorian period, the professions formed a distinct self-sustaining social group with its own mores and values. The project looked at 16,000 individuals drawn from census data for Alnwick, Brighton, Bristol, Dundee, Greenock, Leeds, Merthyr Tydfil, Morpeth, and Winchester. The research project was funded by the UK Economic & Social Research Council and was based at the Universities of Oxford and Northumbria.
OpenAIRE Week: General Assembly Kick off
Creators: name: Persic, Ana
name: Manola, Natalia
name: Assinen, Pauli
name: Kosanovic, Biljana
name: Koukounidou, Sylvia
name: Principe, Pedro
Publisher: name: Zenodo
Year: 2020
Subjects: OpenAIRE
Open Science
EOSC
European Open Science Cloud
UNESCO Open Science Recommendations

description: Presentations during the Kick off session of the OpenAIRE Week, General Assembly. Practical implementation is the next step in making Open Science work. How can this work at an international and European level, and what does this mean in terms of implementing EOSC? In this webinar, the audience got a first-hand look at the draft UNESCO recommendation on Open Science and partnership for Open Science. The session also outlined the role of OpenAIRE in EOSC and focused on national efforts to implement elements of EOSC at national level.
Hong-Ou-Mandel Interference with a Single Atom
Creators: name: Ralley, K. A.
name: Lerner, I. V.
name: Yurkevich, I. V.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The Hong-Ou-Mandel (HOM) effect is widely regarded as the quintessential quantum interference phenomenon in optics. In this work we examine how nonlinearity can smear statistical photon bunching in the HOM interferometer. We model both the nonlinearity and a balanced beam splitter with a single two-level system and calculate a finite probability of anti-bunching arising in this geometry. We thus argue that the presence of such nonlinearity would reduce the visibility in the standard HOM setup, offering some explanation for the diminution of the HOM visibility observed in many experiments. We use the same model to show that the nonlinearity affects a resonant two-photon propagation through a two-level impurity in a waveguide due to a "weak photon blockade" caused by the impossibility of double-occupancy and argue that this effect might be stronger for multi-photon propagation.
description: Added references (see Ref. [9])
Predicting secondary organic aerosol phase state and viscosity and its effect on multiphase chemistry in a regional-scale air quality model
Creators: name: Schmedding, R.
name: Pye, H.O.T.
name: Vizuete, W.
name: Goldstein, A.H.
name: Surratt, J.D.
name: Zhang, H.
name: Thornton, J.A.
name: Chen, Y.
name: Rasool, Q.Z.
name: Zhang, Y.
name: Lopez-Hilfiker, F.D.
Publisher: name: Copernicus GmbH
Year: 2020

description: Atmospheric aerosols are a significant public health hazard and have substantial impacts on the climate. Secondary organic aerosols (SOAs) have been shown to phase separate into a highly viscous organic outer layer surrounding an aqueous core. This phase separation can decrease the partitioning of semi-volatile and low-volatile species to the organic phase and alter the extent of acidcatalyzed reactions in the aqueous core. A new algorithm that can determine SOA phase separation based on their glass transition temperature (Tg), oxygen to carbon (O V C) ratio and organic mass to sulfate ratio, and meteorological conditions was implemented into the Community Multiscale Air Quality Modeling (CMAQ) system version 5.2.1 and was used to simulate the conditions in the continental United States for the summer of 2013. SOA formed at the ground/surface level was predicted to be phase separated with core shell morphology, i.e., aqueous inorganic core surrounded by organic coating 65.4% of the time during the 2013 Southern Oxidant and Aerosol Study (SOAS) on average in the isoprene-rich southeastern United States. Our estimate is in proximity to the previously reported 70% in literature. The phase states of organic coatings switched between semi-solid and liquid states, depending on the environmental conditions. The semi-solid shell occurring with lower aerosol liquid water content (western United States and at higher altitudes) has a viscosity that was predicted to be 102 1012 Pa s, which resulted in organic mass being decreased due to diffusion limitation. Organic aerosol was primarily liquid where aerosol liquid water was dominant (eastern United States and at the surface), with a viscosity < 102 Pa s. Phase separation while in a liquid phase state, i.e., liquid liquid phase separation (LLPS), also reduces reactive uptake rates relative to homogeneous internally mixed liquid morphology but was lower than aerosols with a thick viscous organic shell. The sensitivity cases performed with different phase-separation parameterization and dissolution.
Anderson acceleration for contractive and noncontractive operators
Creators: name: Pollock, Sara
name: Rebholz, Leo
Publisher: name: arXiv
Year: 2019
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65N22, 65B05

description: A one-step analysis of Anderson acceleration with general algorithmic depths is presented. The resulting residual bounds within both contractive and noncontractive settings reveal the balance between the contributions from the higher and lower order terms, which are both dependent on the success of the optimization problem solved at each step of the algorithm. The new residual bounds show the additional terms introduced by the extrapolation produce terms that are of a higher order than was previously understood. In the contractive setting, these bounds sharpen previous convergence and acceleration results. The bounds rely on sufficient linear independence of the differences between consecutive residuals, rather than assumptions on the boundedness of the optimization coefficients, allowing the introduction of a theoretically sound safeguarding strategy. Several numerical tests illustrate the analysis primarily in the noncontractive setting, and demonstrate the use of the method, the safeguarding strategy, and theory-based guidance on dynamic selection of the algorithmic depth, on a p-Laplace equation, a nonlinear Helmholtz equation, and the steady Navier-Stokes equations with high Reynolds number in three spatial dimensions.
description: 31 pages, 7 figures. Additional numerical examples added
Entropy and complexity analysis of the D-dimensional rigid rotator and hyperspherical harmonics
Creators: name: Dehesa, J. S.
name: Guerrero, A.
name: Sánchez-Moreno, P.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: 94A17, 33C45

description: In this paper we carry out an information-theoretic analysis of the $D$-dimensional rigid rotator by studying the entropy and complexity measures of its wavefunctions, which are controlled by the hyperspherical harmonics. These measures quantify single and two-fold facets of the rich intrinsic structure of the system which are manifest by the intricate and complex variety of D-dimensional geometries of the hyperspherical harmonics. We calculate the explicit expressions of the entropic moments and the Rényi entropies as well as the Fisher-Rényi, Fisher-Shannon and LMC complexities of the system. The explicit expression for the last two complexity measures is not yet possible, mainly because the logarithmic functional of the Shannon entropy has not yet been obtained up until now in a closed for
description: 21 pages, 9 figures
Sudden relaminarisation and lifetimes in forced isotropic turbulence
Creators: name: Linkmann, Moritz
name: Morozov, Alexander
Publisher: name: arXiv
Year: 2015
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: We demonstrate an unexpected connection between isotropic turbulence and wall-bounded shear flows. We perform direct numerical simulations of isotropic turbulence forced at large scales at moderate Reynolds numbers and observe sudden transitions from a chaotic dynamics to a spatially simple flow, analogous to the laminar state in wall bounded shear flows. We find that the survival probabilities of turbulence are exponential and the typical lifetimes increase superexponentially with the Reynolds number. Our results suggest that both isotropic turbulence and wall-bounded shear flows qualitatively share the same phase-space dynamics.
description: 6 pages, 8 figures including supplementary material
ESOF 2020 - Open Research Infrastructure in the field of Science and Innovation Policy Studies: a journey within RISIS and its datasets
Creators: name: Reale, Emanuela
name: Scherngell, Thomas
name: Antonioli Mantegazzini, Barbara
name: Noyons, Ed
name: Laredo, Philippe
name: Fava, Ilaria
name: Jonkers, Koen
name: Klumpers, Johannes
Publisher: name: Zenodo
Year: 2020
Subjects: RISIS infrastructure
indicators
policy debate
Knowmak tool
innovation systems

description: On 4th September ESOF2020 hosted a virtual RISIS Panel to address, discuss, and debate these policy questions which involve the future innovation systems. RISIS Panel at ESOF2020, in particular, focused on the Knowmak-tool with a presentation of Dr. Thomas Scherngell, Dr. Barbara Antonioli Mantegazzini, and Dr. Ed Noyons (The RISIS-KNOWMAK tool providing integrated indicators on research and innovation activities across Europe with use cases as examples).   The illustration of Knowmak-tool has been introduced by an exploration of RISIS activities by Dr. Emanuela Reale and the delineation of strategies and ambitions by Dr. Philippe Laredo, the RISIS project coordinator. The last part of the virtual conference has been dedicated to policy questions with a session entitled Addressing research and policy questions using RISIS resources and with the involvement of Dr. Ilaria Fava (Georg-August-Universität Göttingen), Dr. Koen Jonkers (DG Joint Research Centre, European Commission) and Dr. Johannes Klumpers (Head of Research and Industrial Infrastructures Unit at European Commission).
Odd-frequency pairs and anomalous proximity effect in nematic and chiral states of superconducting topological insulators
Creators: name: Mizushima, Takeshi
name: Tamura, Shun
name: Yada, Keiji
name: Tanaka, Yukio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We investigate emergent odd-frequency pairs and proximity effect in nematic and chiral states of superconducting topological insulators (STIs), such as $M_x$Bi$_2$Se$_3$ ($M=$ Cu, Sr, Nb). The interplay of superconducting gap symmetry, the orbital degrees of freedom, and strong spin-orbit interaction generates a variety of odd-frequency pairs in the bulk and surface of STIs. The nematic and chiral states are the prototypes of topological superconductors with and without time-reversal symmetry, respectively. We find that the Fermi surface evolution from a closed spheroidal to an open cylindrical shape gives rise to the evolution of the emergent odd-frequency pairs and surface Andreev bound states (SABSs). In addition, spin polarization of odd-frequency pairs and SABSs stems from the non-unitary pairing in the chiral state. These evolution and spin polarization of odd-frequency pairs and SABSs can be captured by tunnel conductance spectroscopy. Furthermore, we study the anomalous proximity effect in various irreducible representations of STIs. The anomalous proximity effect is originally predicted in spin-triplet superconductor junctions without spin-orbit interaction; Odd-frequency spin-triplet $s$-wave pairs penetrate into diffusive normal metals (DN) and induce a pronounced zero-energy peak of the local density of states in the DN region. Here we demonstrate that contrary to the well-known results, the anomalous proximity effect in STIs is not immune to nonmagnetic impurities. The fragility is attributed to the fact that the proximitized odd-frequency even-parity pairs are admixtures of $s$-wave and non-$s$-wave pairs due to strong spin-orbit interaction inherent to the parent materials.
description: 27 pages, 21 figures
Probing U(1) extensions of the MSSM at the LHC Run I and in dark matter searches
Creators: name: Belanger, G.
name: Da Silva, J.
name: Laa, U.
name: Pukhov, A.
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The U(1) extended supersymmetric standard model (UMSSM) can accommodate a Higgs boson at 125 GeV without relying on large corrections from the top/stop sector. After imposing LHC results on the Higgs sector, on B-physics and on new particle searches as well as dark matter constraints, we show that this model offers two viable dark matter candidates, the right-handed (RH) sneutrino or the neutralino. Limits on supersymmetric partners from LHC simplified model searches are imposed using SModelS and allow for light squarks and gluinos. Moreover the upper limit on the relic abundance often favours scenarios with long-lived particles. Searches for a Z' at the LHC remain the most unambiguous probes of this model. Interestingly, the D-term contributions to the sfermion masses allow to explain the anomalous magnetic moment of the muon in specific corners of the parameter space with light smuons or left-handed (LH) sneutrinos. We finally emphasize the interplay between direct searches for dark matter and LHC simplified model searches.
description: 55 pages, 29 figures; v2: references added; v3: clarifications, mostly about presentation and summary of missing topologies, added; v4: matches published version
Gauge Symmetries and Renormalization
Creators: name: Prinz, David
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences
subject: 81T13, 81T15, 83C47

description: We study the perturbative renormalization of quantum gauge theories in the Hopf algebra setup of Connes and Kreimer. It was shown by van Suijlekom (2007) that the quantum counterparts of gauge symmetries -- the so-called Ward--Takahashi and Slavnov--Taylor identities -- correspond to Hopf ideals in the respective renormalization Hopf algebra. We generalize this correspondence to super- and non-renormalizable Quantum Field Theories, extend it to theories with multiple coupling constants and add a discussion on transversality. In particular, this allows us to apply our results to (effective) Quantum General Relativity, possibly coupled to matter from the Standard Model, as was suggested by Kreimer (2008). To this end, we introduce different gradings on the renormalization Hopf algebra and study combinatorial properties of the superficial degree of divergence. Then we generalize known coproduct and antipode identities to the super- and non-renormalizable cases and to theories with multiple vertex residues. Building upon our main result, we provide criteria for the compatibility of these Hopf ideals with the corresponding renormalized Feynman rules. A direct consequence of our findings is the well-definedness of the Corolla polynomial for Quantum Yang--Mills theory without reference to a particular renormalization scheme.
description: 45 pages, 6 figures, article; minor revisions and added material; version to appear in Mathematical Physics, Analysis and Geometry
Analytic eigenbranches in the semi-classical limit
Creators: name: Haller, Stefan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Spectral Theory (math.SP)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35P20

description: We consider a one parameter family of Laplacians on a closed manifold and study the semi-classical limit of its analytically parametrized eigenvalues. Our results are analogous to a theorem for scalar Schrödinger operators on Euclidean space by Luc Hillairet and apply to geometric operators like Witten's Laplacian associated with a Morse function.
On the submetrizability number and $i$-weight of quasi-uniform spaces and paratopological groups
Creators: name: Banakh, Taras
name: Ravsky, Alex
Publisher: name: arXiv
Year: 2015
Subjects: subject: General Topology (math.GN)
subject: FOS: Mathematics
subject: 54D10, 54D15, 54E15, 22A30

description: We derive many upper bounds on the submetrizability number and $i$-weight of paratopological groups and topological monoids with open shifts. In particular, we prove that each first countable Hausdorff paratopological group is submetrizable thus answering a problem of Arhangelskii posed in 2002. Also we construct an example of a zero-dimensional (and hence regular) Hausdorff paratopological abelian group $G$ with countable pseudocharacter which is not submetrizable. In fact, all results on the $i$-weight and submetrizability are derived from more general results concerning normally quasi-uniformizable and bi-quasi-uniformizable spaces.
description: 22 pages, many diagrams
Surfaces containing two isotropic circles through each point
Creators: name: Morozov, Egor
Publisher: name: arXiv
Year: 2020
Subjects: subject: Differential Geometry (math.DG)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 51B10, 14J26

description: We prove (under some technical assumptions) that each surface in $\mathbb R^3$ containing two arcs of parabolas with axes parallel to $Oz$ through each point has a parametrization $\left(\frac{P(u,v)}{R(u,v)},\frac{Q(u,v)}{R(u,v)},\frac{Z(u,v)}{R^2(u,v)}\right)$ for some $P,Q,R,Z\in\mathbb R[u,v]$ such that $P,Q,R$ have degree at most 1 in $u$ and $v$, and $Z$ has degree at most 2 in $u$ and $v$. The proof is based on the observation that one can consider a parabola with vertical axis as an isotropic circle; this allows us to use methods of the recent work by M. Skopenkov and R. Krasauskas in which all surfaces containing two Euclidean circles through each point are classified. Such approach also allows us to find a similar parametrization for surfaces in $\mathbb R^3$ containing two arbitrary isotropic circles through each point (under the same technical assumptions). Finally, we get some results concerning the top view (the projection along the $Oz$ axis) of the surfaces in question.
description: 17 pages, 8 figures; v2: title changed, new figures added, appendix replaced by a reference to arXiv:1512.09062v3. Many minor additions and improvements
(1180) Richard Green
Creators: name: Professions, Victorian
Publisher: name: University of Oxford
Year: 2022
Subjects: subject: 220201 Business and Labour History
subject: FOS: Philosophy, ethics and religion
subject: History
subject: 140203 Economic History
subject: FOS: Economics and business

description: This three-year research project began in January 2014 and investigated whether, during the Victorian period, the professions formed a distinct self-sustaining social group with its own mores and values. The project looked at 16,000 individuals drawn from census data for Alnwick, Brighton, Bristol, Dundee, Greenock, Leeds, Merthyr Tydfil, Morpeth, and Winchester. The research project was funded by the UK Economic & Social Research Council and was based at the Universities of Oxford and Northumbria.
Chemical tracers of episodic accretion in low-mass protostars
Creators: name: Visser, Ruud
name: Bergin, Edwin A.
name: Jorgensen, Jes K.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Aims: Accretion rates in low-mass protostars can be highly variable in time. Each accretion burst is accompanied by a temporary increase in luminosity, heating up the circumstellar envelope and altering the chemical composition of the gas and dust. This paper aims to study such chemical effects and discusses the feasibility of using molecular spectroscopy as a tracer of episodic accretion rates and timescales. Methods: We simulate a strong accretion burst in a diverse sample of 25 spherical envelope models by increasing the luminosity to 100 times the observed value. Using a comprehensive gas-grain network, we follow the chemical evolution during the burst and for up to 10^5 yr after the system returns to quiescence. The resulting abundance profiles are fed into a line radiative transfer code to simulate rotational spectra of C18O, HCO+, H13CO+, and N2H+ at a series of time steps. We compare these spectra to observations taken from the literature and to previously unpublished data of HCO+ and N2H+ 6-5 from the Herschel Space Observatory. Results: The bursts are strong enough to evaporate CO throughout the envelope, which in turn enhances the abundance of HCO+ and reduces that of N2H+. After the burst, it takes 10^3-10^4 yr for CO to refreeze and for HCO+ and N2H+ to return to normal. The chemical effects of the burst remain visible in the rotational spectra for as long as 10^5 yr after the burst has ended, highlighting the importance of considering luminosity variations when analyzing molecular line observations in protostars. The spherical models are currently not accurate enough to derive robust timescales from single-dish observations. As follow-up work, we suggest that the models be calibrated against spatially resolved observations in order to identify the best tracers to be used for statistically significant source samples.
description: Accepted by A&A; 12 pages, 7 figures
Heterogeneous Hydroxyl Radical Oxidation of Isoprene-Epoxydiol-Derived Methyltetrol Sulfates: Plausible Formation Mechanisms of Previously Unexplained Organosulfates in Ambient Fine Aerosols
Creators: name: Chan, M.N.
name: Ault, A.P.
name: Lambe, A.T.
name: Gold, A.
name: Olson, N.E.
name: Turpin, B.J.
name: Lei, Z.
name: Chen, Y.
name: Szalkowski, T.
name: Xu, R.
name: Zhang, Y.
name: Zhang, Z.
name: Vizuete, W.
name: Cui, T.
name: Surratt, J.D.
Publisher: name: American Chemical Society
Year: 2020

description: Methyltetrol sulfates are unique tracers for secondary organic aerosols (SOA) formed from acid-driven multiphase chemistry of isoprene-derived epoxydiols. 2-Methyltetrol sulfate diastereomers (2-MTSs) are the dominant isomers and single most-abundant SOA tracers in atmospheric fine particulate matter (PM2.5), but their atmospheric sinks remain unknown. We investigated the oxidative aging of authentic 2-MTS aerosols by gas-phase hydroxyl radicals (·OH) at a relative humidity of 61 ± 1%. The effective rate constant for this heterogeneous reaction was determined as 4.9 ± 0.6 × 10-13 cm3 molecules-1 s-1, corresponding to an atmospheric lifetime of 16 ± 2 days (assuming an ·OH concentration of 1.5 × 106 molecules cm-3). Chemical changes to 2-MTSs were monitored by hydrophilic interaction liquid chromatography interfaced to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (HILIC/ESI-HR-QTOFMS). Plausible reaction mechanisms are proposed for previously unknown OSs detected in atmospheric PM2.5 at mass-to-charge ratios (m/z) of 139 (C2H3O5S-), 155 (C2H3O6S-), 169 (C3H5O6S-), 171 (C3H7O6S-), 185 (C3H5O7S-), 199 (C4H7O7S-), 211 (C5H7O7S-), 213 (C5H9O7S-), 227 (C5H7O8S-), 229 (C5H9O8S-), and 231 (C5H11O8S-). Heterogeneous ·OH oxidation of 2-MTSs redistributes the particulate sulfur speciation into more oxygenated/functionalized OSs, likely modifying the aerosol physicochemical properties of SOA containing 2-MTSs.
A guide to self-distributive quasigroups, or latin quandles
Creators: name: Stanovský, David
Publisher: name: arXiv
Year: 2015
Subjects: subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 20N05, 57M27

description: We present an overview of the theory of self-distributive quasigroups, both in the two-sided and one-sided cases, and relate the older results to the modern theory of quandles, to which self-distributive quasigroups are a special case. Most attention is paid to the representation results (loop isotopy, linear representation, homogeneous representation), as the main tool to investigate self-distributive quasigroups.
RISIS policymakers sessions: Exploring higher education institutions classification: a challenge for differentiated policy strategies
Creators: name: Lepori, Benedetto
Publisher: name: Zenodo
Year: 2020
Subjects: RISIS-ETER
universities classification
heterogeneity of Higher Education Institutions
research excellence
RISIS datasets

description: The 5th RISIS Policymakers Session was organized on the 23rd of September in an online format (2 pm – 4 pm). RISIS focused on the heterogeneity of European Higher Institutions with a presentation entitled The heterogeneity of European Higher Education Institutions. A configurational approach by Professor Benedetto Lepori USI (Università della Svizzera italiana). Higher Education Institutions are highly heterogeneous in terms of their profile, governance, and output. This represents a challenge for policies as well, as some issues will be relevant only for a subset of HEI and differentiated policies at the European and national level will be required. For instance, the whole policy discussion on research excellence will be relevant only for a few hundreds of universities, against nearly 3,000 institutions covered by the European Tertiary Education Register (ETER). During the Policymakers Session, Dr. Benedetto Lepori illustrated a proposal of classification of European HEIs based on the extended version of ETER developed in the RISIS project and using novel statistical methods introduced in the RISIS methodological activity. This classification identifies five main classes along two main dimensions, i.e. the balance between research and education and the orientation towards natural and technical sciences vs. social sciences and humanities. Dr Marc Saillard, National Research Agency (FRANCE) added a valuable contribution, describing the evolution and transformation of French academic world in the last decade. Many Universities and Research Centers in France merged together to become more competitive developing projects together.
description: Video of discussion: https://youtu.be/rfSFS3biv0w
Magnetism of solar-like stars through spot impact in light curves
Creators: name: Degott, Lucie
Publisher: name: Zenodo
Year: 2024

description: Non-English characters and , and simple LaTeX math can be used e.g. "A star with mass $<1\times M_\odot$"

The mechanisms behind stellar magnetism remain an open question in stellar physics : there is a huge variety of topologies and magnetic properties and scales. The link between these properties and stellar parameters (radius, mass, age, temperature, or Rossby number) are still elusive. The photometric activity is used here as an observable to improve our understanding of spot characteristics (area, lifetime…) and link these properties to the dynamo effect which rules all these phenomena. We propose to characterize this activity using the signature of spots in the light curves, seen in the Fourier domain. For this, we revisit the model of Harvey et al. (1985) in order to take into account all the components present in the power spectra. This method allows access to two proxies of the activity : the mean spot coverage and the lifetime of the spots. After validating this model with simulated light curves, we present the results from thousands of Kepler light curves of main sequence stars used by McQuillan (2014) and Santos (2022). The results show the emergence of three different regimes of activity related to different level of spot coverage and long or short spot lifetime. These regimes are linked to different stars properties such as their rotation period, mass and the Rossby number, which can provide information about the stellar dynamo evolution.
(1177) William Alexander Smith
Creators: name: Professions, Victorian
Publisher: name: University of Oxford
Year: 2022
Subjects: subject: 220201 Business and Labour History
subject: FOS: Philosophy, ethics and religion
subject: History
subject: 140203 Economic History
subject: FOS: Economics and business

description: This three-year research project began in January 2014 and investigated whether, during the Victorian period, the professions formed a distinct self-sustaining social group with its own mores and values. The project looked at 16,000 individuals drawn from census data for Alnwick, Brighton, Bristol, Dundee, Greenock, Leeds, Merthyr Tydfil, Morpeth, and Winchester. The research project was funded by the UK Economic & Social Research Council and was based at the Universities of Oxford and Northumbria.
Large deviations, condensation, and giant response in a statistical system
Creators: name: Corberi, Federico
Publisher: name: arXiv
Year: 2015
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study the probability distribution $P$ of the sum of a large number of non-identically distributed random variables $n_m$. Condensation of fluctuations, the phenomenon whereby one of such variables provides a macroscopic contribution to the global probability, is discussed and interpreted in analogy to phase-transitions in Statistical Mechanics. A general expression for $P$ is derived, and its sensitivity to the details of the distribution of a single $n_m$ is worked out. These general results are verified by the analytical and numerical solution of some specific examples.
description: New improved and extended version (12 pages, 4 figures) with more references and additional discussions. To appear in J. Phys. A: Math. Theor
The Minimal Genus of Homology Classes in a Finite 2-Complex
Creators: name: Kastenholz, Thorben
name: Pedron, Mark
Publisher: name: arXiv
Year: 2020
Subjects: subject: Geometric Topology (math.GT)
subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 57R95

description: We study surface representatives of homology classes of finite complexes which minimize certain complexity measures, including its genus and Euler characteristic. Our main result is that up to surgery at nullhomotopic curves minimizers are homotopic to cellwise coverings to the 2-skeleton. From this we conclude that the minimizing problem is in general algorithmically undecidable, but can be solved for 2-dimensional CAT(-1)-complexes.
EOSC - a tool for enabling Open Science in Europe
Creators: name: Appleton, Owen
name: Asmi, Ari
name: Bird, Ian
name: Dekker, Ron
name: Blomberg, Niklas
name: Dimper, Rudolf
name: Ferrari, Tiziana
name: Grant, Annabel
name: Jones, Sarah
name: Manola, Natalia
name: Petzold, Andreas
name: Rettberg, Najla
name: Robertson, Dale
name: Tenhunen, Ville
name: Testi, Debora
name: Sanden, Mark Van De
Publisher: name: Zenodo
Year: 2020
Subjects: European Open Science Cloud, ESFRI, e-Infrastructures

description: The European Open Science Cloud (EOSC) will “enable a trusted, virtual, federated environment in Europe to store, share and reuse digital outputs from research (including publications, data, metadata and software) across borders and scientific disciplines”1. Today, at
 the end of 2020, many building blocks are in place and on-going EOSC projects endeavour to enrich the EOSC ecosystem. To ensure strong engagement by research communities, we believe that this is the time to re-orient the EOSC activities towards higher relevance for these communities. The Science Clusters ENVRI-FAIR , EOSC-LIFE , ESCAPE , PaNOSC , SSHOC bring together 72 world-class research infrastructures from the ESFRI roadmap and beyond to work on FAIR data management and connecting their user communities to the EOSC. The European e-infrastructures EGI , EUDAT , GÉANT , and OpenAIRE provide inclusive services across Europe and beyond to the benefit of science.
Experimental mode-pairing measurement-device-independent quantum key distribution without global phase-locking
Creators: name: Zhu, Hao-Tao
name: Huang, Yizhi
name: Liu, Hui
name: Zeng, Pei
name: Zou, Mi
name: Dai, Yunqi
name: Tang, Shibiao
name: Li, Hao
name: You, Lixing
name: Wang, Zhen
name: Chen, Yu-Ao
name: Ma, Xiongfeng
name: Chen, Teng-Yun
name: Pan, Jian-Wei
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In the past two decades, quantum key distribution networks based on telecom fibers have been implemented on metropolitan and intercity scales. One of the bottlenecks lies in the exponential decay of the key rate with respect to the transmission distance. Recently proposed schemes mainly focus on achieving longer distances by creating a long-arm single-photon interferometer over two communication parties. Despite their advantageous performance over long communication distances, the requirement of phase-locking between two independent lasers is technically challenging. By adopting the recently-proposed mode-pairing idea, we realize high-performance quantum key distribution without global phase-locking. Using two independent off-the-shelf lasers, we show a quadratic key-rate improvement over the conventional measurement-device-independent schemes in the regime of metropolitan and intercity distances. For longer distances, we also boost the key rate performance by three orders of magnitude via 304 km commercial fiber and 407 km ultra-low-loss fiber. We expect this ready-to-implement high-performance scheme to be widely used in future intercity quantum communication networks.
description: 19 pages, 9 figures, 7 tables
Extrusion of magnesium alloy hollow profiles with axial variable wall thickness
Creators: name: Negendank, Maik
name: Sanabria, Vidal
name: Müller, Sören
name: Reimers, Walter
Publisher: name: Technische Universität Berlin
Year: 2019
Subjects: subject: 620 Ingenieurwissenschaften und zugeordnete Tätigkeiten
subject: alloys
subject: magnesium
subject: extrusion
subject: wall thickness
subject: AZ31

description: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in AIP Conference Proceedings 2113, 030002 (2019) and may be found at https://doi.org/10.1063/1.5112530.
description: Industrially extruded profiles are characterized by a constant cross section along the length since rigid dies are applied in the process. However, if it would be possible to extrude profiles with cross sections that can be locally adapted (tailored) to the acting forces or stresses this would mean a significant potential for weight and material savings. Hence, in this study the extrusion of magnesium hollow profiles with axial variable wall thickness was investigated. Therefore, a newly developed porthole die was applied and extrusion trials conducted in order to show the feasibility of producing load adapted magnesium hollow profiles with axially variable wall thickness. Billets of magnesium alloy AZ31 were extruded and the required extrusion force was measured vs. process time. After the extrusion tryouts the manufactured hollow profile sections were measured with respect to the obtained wall thickness, inner and outer diameter of the thin-walled and the thick-walled sections, and in the wall thickness transition areas. The feasibility of manufacturing AZ31 hollow profiles with axially variable wall thickness was proven successfully. A maximal wall thickness variation of Δt=1.0 mm was achieved.
Structural Inference of Networked Dynamical Systems with Universal Differential Equations
Creators: name: Koch, James
name: Chen, Zhao
name: Tuor, Aaron
name: Drgona, Jan
name: Vrabie, Draguna
Publisher: name: arXiv
Year: 2022
Subjects: subject: Dynamical Systems (math.DS)
subject: Machine Learning (cs.LG)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Networked dynamical systems are common throughout science in engineering; e.g., biological networks, reaction networks, power systems, and the like. For many such systems, nonlinearity drives populations of identical (or near-identical) units to exhibit a wide range of nontrivial behaviors, such as the emergence of coherent structures (e.g., waves and patterns) or otherwise notable dynamics (e.g., synchrony and chaos). In this work, we seek to infer (i) the intrinsic physics of a base unit of a population, (ii) the underlying graphical structure shared between units, and (iii) the coupling physics of a given networked dynamical system given observations of nodal states. These tasks are formulated around the notion of the Universal Differential Equation, whereby unknown dynamical systems can be approximated with neural networks, mathematical terms known a priori (albeit with unknown parameterizations), or combinations of the two. We demonstrate the value of these inference tasks by investigating not only future state predictions but also the inference of system behavior on varied network topologies. The effectiveness and utility of these methods is shown with their application to canonical networked nonlinear coupled oscillators.
Conformance Checking Based on Multi-Perspective Declarative Process Models
Creators: name: Burattin, Andrea
name: Maggi, Fabrizio Maria
name: Sperduti, Alessandro
Publisher: name: arXiv
Year: 2015
Subjects: subject: Software Engineering (cs.SE)
subject: Databases (cs.DB)
subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences

description: Process mining is a family of techniques that aim at analyzing business process execution data recorded in event logs. Conformance checking is a branch of this discipline embracing approaches for verifying whether the behavior of a process, as recorded in a log, is in line with some expected behaviors provided in the form of a process model. The majority of these approaches require the input process model to be procedural (e.g., a Petri net). However, in turbulent environments, characterized by high variability, the process behavior is less stable and predictable. In these environments, procedural process models are less suitable to describe a business process. Declarative specifications, working in an open world assumption, allow the modeler to express several possible execution paths as a compact set of constraints. Any process execution that does not contradict these constraints is allowed. One of the open challenges in the context of conformance checking with declarative models is the capability of supporting multi-perspective specifications. In this paper, we close this gap by providing a framework for conformance checking based on MP-Declare, a multi-perspective version of the declarative process modeling language Declare. The approach has been implemented in the process mining tool ProM and has been experimented in three real life case studies.
Ambient measurements of monoterpenes near Cannabis cultivation facilities in Denver, Colorado
Creators: name: Rasool, Q.Z.
name: Wang, C.-T.
name: Vizuete, W.
name: Wiedinmyer, C.
name: Ortega, J.
name: Ashworth, K.
name: Harley, P.C.
Publisher: name: Elsevier Ltd
Year: 2020

description: Colorado was one of the first US states to legalize the industrial-scale cultivation of Cannabis spp. for recreational purposes. In March 2018, there were 609 indoor Cannabis cultivation facilities (CCFs) in operation in Denver County with a recorded 550,000 mature plants (higher than 8 inches) under cultivation at any given time. It is known that cultivation of Cannabis spp. produces emissions of a group of highly reactive hydrocarbons, monoterpenes. There have been limited studies that have quantified mixing ratios of emitted monoterpenes in air outside CCFs. A field campaign was conducted in August 2016 in Denver County focused on six different CCF clusters near the intersection of interstate highways I-25 and I-70 during which a total of 150 ambient air samples were collected. Monoterpene mixing ratios near CCFs were ~408 ± 203 pptv; 4–8 times higher than samples collected from a “background” site located at the Denver City Park (75 ± 25 pptv). The composition of samples taken near CCFs were dominated by d-limonene (30%), β-myrcene (20%), and α-pinene (15%), which is similar to previously reported emission factors for Cannabis spp. Since β-myrcene was only detected in leaf enclosure studies, indoor CCF observations and ambient samples near CCFs and not detected at a background site, this particular compound could be used as a tracer for the Denver Cannabis production industry. The monoterpene speciation in ambient measurements varied across Denver suggesting differences in emissions between different Cannabis spp., or different growth stages. Given the observed variabilities in both composition and emission rates, it is critical for the accuracy of emissions inventories to develop strain-specific emission factors. This information, coupled with detailed information on each CCF, would greatly reduce the uncertainties currently present in monoterpene emission estimates for the Cannabis industry and their potential impact on air quality.
(1179) William Tarbet
Creators: name: Professions, Victorian
Publisher: name: University of Oxford
Year: 2022
Subjects: subject: 220201 Business and Labour History
subject: FOS: Philosophy, ethics and religion
subject: History
subject: 140203 Economic History
subject: FOS: Economics and business

description: This three-year research project began in January 2014 and investigated whether, during the Victorian period, the professions formed a distinct self-sustaining social group with its own mores and values. The project looked at 16,000 individuals drawn from census data for Alnwick, Brighton, Bristol, Dundee, Greenock, Leeds, Merthyr Tydfil, Morpeth, and Winchester. The research project was funded by the UK Economic & Social Research Council and was based at the Universities of Oxford and Northumbria.
Backward rod extrusion of bimetallic aluminum-copper alloys at room temperature
Creators: name: Sanabria, Vidal
name: Gall, Sven
name: Gensch, Felix
name: Nitschke, René
name: Müller, Sören
Publisher: name: Technische Universität Berlin
Year: 2019
Subjects: subject: 620 Ingenieurwissenschaften und zugeordnete Tätigkeiten
subject: alloys
subject: carbon based materials
subject: extrusion
subject: aluminum alloy
subject: copper alloy
subject: friction

description: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in AIP Conference Proceedings 2113, 030001 (2019) and may be found at https://doi.org/10.1063/1.5112529.
description: The backward rod extrusion of bimetallic aluminum-copper alloys at room temperature was investigated. The aluminum alloy EN AW-1080A and the copper alloy Cu-ETP were selected to prepare the core and sleeve of the billet respectively. The copper cross section was equivalent to 30% of the billet. Moreover, the billet was extruded applying a conic die angle of 90° and an extrusion ratio of 14:1. Experimental results demonstrated that the combination of grounding marks on the die surface and the application of graphite foil reduced drastically the friction between copper and the conic die. Thus, a uniform material flow of aluminum and copper through the bearing channel was observed during the steady state of the extrusion process. However multiple fractures of the copper sleeve occurred at the end of the process. The extrusion process was numerically simulated applying the FEM-based software Deform 2D in order to estimate the state variables and material flow. The die and punch temperature evolution, as well as the die extrusion force were recorded during the whole process to facilitate the validation of the numerical analysis.