cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Trauma, catastrophe, and contemporary conflicts: documentary strategies for the narration of violence
Creators: name: Cardoso, Eduardo Prado
Publisher: name: Diffractions
Year: 2023

description: This essay is a direct result coming after an immersive and collaborative experience at the Documentary Summer School that took place in 2022 in Switzerland, a joint effort between the Università della Svizzera italiana and the 75th edition of the Locarno Film Festival. As such, it aims at collecting a few impressions about the state of the art of documentary production, particularly when concerned with modes of narrating violence. Besides the thematic sections that may group the films together, a few general points regarding different documental procedures will be teased out, to engage with scholarly research on themes such as trauma and catastrophe and thus give room to further academic exploration. The films analyzed are: The Hamlet Syndrome, The River is not a Border, It Is Night in America and Matter Out of Place.
description: Diffractions, n. 6 (2023): Images in Movement
Entanglement from Dissipation and Holographic Interpretation
Creators: name: Cantcheff, M. Botta
name: Gadelha, Alexandre L.
name: Marchioro, Dáfni F. Z.
name: Nedel, Daniel Luiz
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we study a dissipative field theory where the dissipation process is manifestly related to dynamical entanglement and put it in the holographic context. Such endeavour is realized by further development of a canonical approach to study quantum dissipation, which consists of doubling the degrees of freedom of the original system by defining an auxiliary one. A time dependent entanglement entropy for the vacumm state is calculated and a geometrical interpretation of the auxiliary system and the entropy is given in the context of the AdS/CFT correspondence using the Ryu-Takayanagi formula. We show that the dissipative dynamics is controlled by the entanglement entropy and there are two distinct stages: in the early times the holographic interpretation requires some deviation from classical General Relativity; in the later times the quantum system is described as a wormhole, a solution of the Einstein's equations near to a maximally extended black hole with two asymptotically AdS boundaries. We focus our holographic analysis in this regime, and suggest a mechanism similar to teleportation protocol to exchange (quantum) information between the two CFTs on the boundaries (see [28]).
description: Major changes. Last section removed from the old version. New section on the dual gravitational solution and the teleportation mechanism included. Figure added. References changed
Solar Atmospheric Neutrinos and the Sensitivity Floor for Solar Dark Matter Annihilation Searches
Creators: name: Argüelles, C. A.
name: de Wasseige, G.
name: Fedynitch, A.
name: Jones, B. J. P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Cosmic rays interacting in the solar atmosphere produce showers that result in a flux of high-energy neutrinos from the Sun. These form an irreducible background to indirect solar WIMP co-annihilation searches, which look for heavy dark matter particles annihilating into final states containing neutrinos in the Solar core. This background will eventually create a sensitivity floor for indirect WIMP co-annihilation searches analogous to that imposed by low-energy solar neutrino interactions for direct dark matter detection experiments. We present a new calculation of the flux of solar atmospheric neutrinos with a detailed treatment of systematic uncertainties inherent in solar atmospheric shower evolution, and we use this to derive the sensitivity floor for indirect solar WIMP annihilation analyses. We find that the floor lies less than one order of magnitude beyond the present experimental limits on spin-dependent WIMP-proton cross sections for some mass points, and that the high-energy solar atmospheric neutrino flux may be observable with running and future neutrino telescopes.
description: 21 pages, 11 figures
Surfaces and Slabs of Fractional Topological Insulator Heterostructures
Creators: name: Sahoo, Sharmistha
name: Sirota, Alexander
name: Cho, Gil Young
name: Teo, Jeffrey C. Y.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Fractional topological insulators (FTI) are electronic topological phases in $(3+1)$ dimensions enriched by time reversal (TR) and charge $U(1)$ conservation symmetries. We focus on the simplest series of fermionic FTI, whose bulk quasiparticles consist of deconfined partons that carry fractional electric charges in integral units of $e^\ast=e/(2n+1)$ and couple to a discrete $\mathbb{Z}_{2n+1}$ gauge theory. We propose massive symmetry preserving or breaking FTI surface states. Combining the long-ranged entangled bulk with these topological surface states, we deduce the novel topological order of quasi-$(2+1)$ dimensional FTI slabs as well as their corresponding edge conformal field theories.
description: 7 pages, 1 figure
How Bright are Planet-Induced Spiral Arms in Scattered Light?
Creators: name: Dong, Ruobing
name: Fung, Jeffrey
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Recently, high angular resolution imaging instruments such as SPHERE and GPI have discovered many spiral-arm-like features in near-infrared scattered light images of protoplanetary disks. Theory and simulations have suggested that these arms are most likely excited by planets forming in the disks; however, a quantitative relation between the arm-to-disk brightness contrast and planet mass is still missing. Using 3D hydrodynamics and radiative transfer simulations, we examine the morphology and contrast of planet-induced arms in disks. We find a power-law relation for the face-on arm contrast ($δ_{\rm max}$) as a function of planet mass ($M_{\rm p}$) and disk aspect ratio ($h/r$): $δ_{\rm max}\approx((M_{\rm p}/M_{\rm J})/(h/r)^{1.38})^{0.22}$. With current observational capability, at a 30 AU separation, the minimum planet mass for driving detectable arms in a disk around a 1 Myr 1$M_\odot$ star at 140 pc at low inclinations is around Saturn mass. For planets more massive than Neptune masses, they typically drive multiple arms. Therefore in observed disks with spirals, it is unlikely that each spiral arm originates from a different planet. We also find only massive perturbers with at least multi-Jupiter masses are capable of driving bright arms with $δ_{\rm max}\gtrsim2$ as found in SAO 206462, MWC 758, and LkH$α$~330, and these arms do not follow linear wave propagation theory. Additionally, we find the morphology and contrast of the primary and secondary arms are largely unaffected by a modest level of viscosity with $α\lesssim0.01$. Finally, the contrast of the arms in the SAO 206462 disk suggests that the perturber SAO 206462 b at $\sim100$ AU is about $5-10M_{\rm J}$ in mass.
description: 37 pages, 14 figures, 1 table; ApJ published
The Wilson loop CFT: Insertion dimensions and structure constants from wavy lines
Creators: name: Cooke, Michael
name: Dekel, Amit
name: Drukker, Nadav
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study operator insertions into the $1/2$ BPS Wilson loop in ${\cal N}=4$ SYM theory and determine their two-point coefficients, anomalous dimensions and structure constants. The calculation is done for the first few lowest dimension insertions and relies on known results for the expectation value of a smooth Wilson loop. In addition to the particular coefficients that we calculate, our study elucidates the connection between deformations of the line and operator insertions and between the vacuum expectation value of the line and the CFT data of the insertions.
description: 23 pages. v2: minor corrections
Andrew Kötting’s Louyre: This Our Still Life. An Archival Reading
Creators: name: Voukena, Maria
name: Mermigka, Ioulia
Publisher: name: Diffractions
Year: 2023

description: The paper explores the experimental documentary Louyre: This Our Still Life (2011) by the subversive British filmmaker Andrew Kötting, drawing on contemporary conceptualizations of archival art. It reads the film as “anarchival” through the lens of Derrida’s psychoanalytic deconstruction of the concept of the archive and the curational discourses that were influenced by it. Furthermore, placing the film within a democratic horizon, the paper argues that the film is also a counter-archive, in that, as a public archive that sublimates trauma, it enunciates counter-hegemonic, non-patriarchal discourses on art, disability and care.
description: Diffractions, n. 6 (2023): Images in Movement
The Thiemann Complexifier and the CVH algebra for Classical and Quantum FLRW Cosmology
Creators: name: Achour, Jibril Ben
name: Livine, Etera R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In the context of Loop Quantum Gravity (LQG), we study the fate of Thiemann complexifier in homogeneous and isotropic FRW cosmology. The complexifier is the dilatation operator acting on the canonical phase space for gravity and generates the canonical transformations shifting the Barbero-Immirzi parameter. We focus on the closed algebra consisting in the complexifier, the 3d volume and the Hamiltonian constraint, which we call the CVH algebra. In standard cosmology, for gravity coupled to a scalar field, the CVH algebra is identified as a su(1,1) Lie algebra, with the Hamiltonian as a null generator, the complexifier as a boost and the su(1,1) Casimir given by the matter density. The loop gravity cosmology approach introduces a regularization length scale $λ$ and regularizes the gravitational Hamiltonian in terms of SU(2) holonomies. We show that this regularization is compatible with the CVH algebra, if we suitably regularize the complexifier and inverse volume factor. The regularized complexifier generates a generalized version of the Barbero's canonical transformation which reduces to the classical one when $λ\rightarrow 0$. This structure allows for the exact integration of the actions of the Hamiltonian constraints and the complexifier. This straightforwardly extends to the quantum level: the cosmological evolution is described in terms of SU(1,1) coherent states and the regularized complexifier generates unitary transformations. The Barbero-Immirzi parameter is to be distinguished from the regularization scale $λ$, it can be rescaled unitarily and the Immirzi ambiguity ultimately disappears from the physical predictions of the theory. Finally, we show that the complexifier becomes the effective Hamiltonian when deparametrizing the dynamics using the scalar field as a clock, thus underlining the deep relation between cosmological evolution and scale
description: 38 pages; Corrected version accepted for publication in PRD with clarifications on role of Immirzi parameter and minimal volume
Not made for you: the genre of Man in The BlackTransArchive
Creators: name: Kruijt, Eva Lisa
Publisher: name: Diffractions
Year: 2023

description: This paper explores the ways in which the videogame The BlackTransArchive reflects on and subverts the implicit rules that are in place regarding what it means to be perceived and treated as a human being. The videogame was created for and by black trans people in order to store and centre black trans lives, thoughts and experience, which have been (and are) at risk of being erased. Following Sylvia Wynter’s theories regarding the genre of Man standing in for the category of “human” as a whole, this paper argues that The BlackTransArchive’s target audience and its centring of its players’ identities and choices are equipped to depart from and reflect critically on the Man-as-human episteme and Man as the implicit default audience of video games. It shows that the game and its characters depict cyborg characteristics – both in their potential for resisting Man, and their inevitable complicity in Man’s systems.
description: Diffractions, n. 6 (2023): Images in Movement
Ultra-fast control of magnetic relaxation in a periodically driven Hubbard model
Creators: name: Mendoza-Arenas, Juan Jose
name: Gomez-Ruiz, Fernando Javier
name: Eckstein, Martin
name: Jaksch, Dieter
name: Clark, Stephen R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Motivated by cold atom and ultra-fast pump-probe experiments we study the melting of long-range antiferromagnetic order of a perfect Néel state in a periodically driven repulsive Hubbard model. The dynamics is calculated for a Bethe lattice in infinite dimensions with non-equilibrium dynamical mean-field theory. In the absence of driving melting proceeds differently depending on the quench of the interactions to hopping ratio $U/J_0$ from the atomic limit. For $U \gg J_0$ decay occurs due to mobile charge-excitations transferring energy to the spin sector, while for $J_0 \gtrsim U$ it is governed by the dynamics of residual quasi-particles. Here we explore the rich effects strong periodic driving has on this relaxation process spanning three frequency $ω$ regimes: (i) high-frequency $ω\gg U,J_0$, (ii) resonant $lω= U > J_0$ with integer $l$, and (iii) in-gap $U > ω> J_0$ away from resonance. In case (i) we can quickly switch the decay from quasi-particle to charge-excitation mechanism through the suppression of $J_0$. For (ii) the interaction can be engineered, even allowing an effective $U=0$ regime to be reached, giving the reverse switch from a charge-excitation to quasi-particle decay mechanism. For (iii) the exchange interaction can be controlled with little effect on the decay. By combining these regimes we show how periodic driving could be a potential pathway for controlling magnetism in antiferromagnetic materials. Finally, our numerical results demonstrate the accuracy and applicability of matrix product state techniques to the Hamiltonian DMFT impurity problem subjected to strong periodic driving.
Making paradise: The Island of Demons (1933) by Friedrich Dalsheim
Creators: name: Von Plessen, Louise
name: Amaral, Gustavo
Publisher: name: Diffractions
Year: 2023

description: The present article discusses visual anthropology, otherness and documentary practice as research by the example of the cultural film THE ISLAND OF DEMONS (1933) directed by German filmmaker and ethnologist Friedrich Dalsheim (1895-1936). THE ISLAND OF DEMONS was shot on Bali in 1931/32, at a time when Bali, belonging to the Dutch East Indies, the Dutch colonial empire, was perceived as the newly discovered „last paradise“ and due to the presence of the painter, musician and bohemian Walter Spies (1895-1942) mutated into the most popular escapist island among Western artists including Vicki Baum and Charlie Chaplin. Until today, THE ISLAND OF DEMONS is a unique ethnographic and historic document of Balinese culture, its village community life in harmony with nature, its rituals, beliefs, music and above all its cultural dances such as the famous Kecak dance, the Sanghyang Dedari and Legong dance as well as an extraordinary study of documentary practice in the realm of documentary and feature film since Dalsheim and his team did not come to Bali with a developed or „Europeanized“ or „Americanized“ screenplay, but developed it only on location with the Balinese village elders and community after months of discussions and ethnographic field research.
description: Diffractions, n. 6 (2023): Images in Movement
Improper Colourings inspired by Hadwiger's Conjecture
Creators: name: Heuvel, Jan van den
name: Wood, David R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: Hadwiger's Conjecture asserts that every $K_t$-minor-free graph has a proper $(t-1)$-colouring. We relax the conclusion in Hadwiger's Conjecture via improper colourings. We prove that every $K_t$-minor-free graph is $(2t-2)$-colourable with monochromatic components of order at most $\lceil{\frac12(t-2)}\rceil$. This result has no more colours and much smaller monochromatic components than all previous results in this direction. We then prove that every $K_t$-minor-free graph is $(t-1)$-colourable with monochromatic degree at most $t-2$. This is the best known degree bound for such a result. Both these theorems are based on a decomposition method of independent interest. We give analogous results for $K_{s,t}$-minor-free graphs, which lead to improved bounds on generalised colouring numbers for these classes. Finally, we prove that graphs containing no $K_t$-immersion are $2$-colourable with bounded monochromatic degree.
What is the Mass of a Gap-Opening Planet?
Creators: name: Dong, Ruobing
name: Fung, Jeffrey
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: High contrast imaging instruments such as GPI and SPHERE are discovering gap structures in protoplanetary disks at an ever faster pace. Some of these gaps may be opened by planets forming in the disks. In order to constrain planet formation models using disk observations, it is crucial to find a robust way to quantitatively back out the properties of the gap-opening planets, in particular their masses, from the observed gap properties, such as their depths and widths. Combing 2D and 3D hydrodynamics simulations with 3D radiative transfer simulations, we investigate the morphology of planet-opened gaps in near-infrared scattered light images. Quantitatively, we obtain correlations that directly link intrinsic gap depths and widths in the gas surface density to observed depths and widths in images of disks at modest inclinations under finite angular resolution. Subsequently, the properties of the surface density gaps enable us to derive the disk scale height at the location of the gap $h$, and to constrain the quantity $M_{\rm p}^2/α$, where $M_{\rm p}$ is the mass of the gap-opening planet and $α$ characterizes the viscosity in the gap. As examples, we examine the gaps recently imaged by VLT/SPHERE, Gemini/GPI, and Subaru/HiCIAO in HD 97048, TW Hya, HD 169142, LkCa 15, and RX J1615.3-3255. Scale heights of the disks and possible masses of the gap-opening planets are derived assuming each gap is opened by a single planet. Assuming $α=10^{-3}$, the derived planet mass in all cases are roughly between 0.1-1 $M_{\rm J}$.
description: 40 pages (single column), 14 figures, 2 tables, ApJ published
Correlation between Afrofuturism and science fiction in Space is the Place: praxis or paradox?
Creators: name: Fofie, Gloria Adjeiwaa
Publisher: name: Diffractions
Year: 2023

description: In this paper, I use the culture studies approach to investigate how themes such as the space age, psychedelia and the creation of a post-apocalyptic black colony in the film Space is the Place (Coney 1972), interweave with Darko Suvin's (1974) concept of cognitive estrangement and novum. I specifically study how these relate to science fiction, with the goal of subverting the stereotype of blackness as uncivilised and Luddite. I propose to critically review the general categorization of the film as Afrofuturist and argue that what is positioned in the film as a novelty and salvation is, in fact, constructed in a problematic way. As such, positioning the film just as Afrofuturist, as demonstrated, may contradict the genre’s goals. Instead, I follow David Seed’s proposal to use an interdisciplinary reading method for film analysis based on deconstructing the relation of the film within the two framings: Science fiction and Afrofuturism.
description: Diffractions, n. 6 (2023): Images in Movement
Methods which enhanced the representation of experiences of recovery and addiction in animation
Creators: name: Smyth, Mary
Publisher: name: Diffractions
Year: 2023

description: This discussion considers qualitative and practice methodology as part of a PhD animation project on addiction recovery. This article outlines the data collection process, considers the analysis to production, and illustrate benefits of multi-method research in production. Collaborating with Aiséirí, a long-established addiction treatment service in Ireland, a qualitative study involving three focus groups with recoverees provided various Irish perspectives. The addition of arts-tools within these sessions provided supplementary insights, such as key journey points to recovery, representations of addiction, a cultural window to deeper understanding of the relationship to and perception of addiction and recovery, and visual research for animation development. The analysis worked in an iterative process with film development adapting a thematic analysis. Themes were then developed and created into two animated short films. This article uses examples from The Click (2021) which through its structure showcase 5 distinct journey points found from addiction to recovery.
description: Diffractions, n. 6 (2023): Images in Movement
The $r$th moment of the divisor function: an elementary approach
Creators: name: Luca, Florian
name: Tóth, László
Publisher: name: arXiv
Year: 2017
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11N37

description: Let $τ(n)$ be the number of divisors of $n$. We give an elementary proof of the fact that $$ \sum_{n\le x} τ(n)^r =xC_{r} (\log x)^{2^r-1}+O(x(\log x)^{2^r-2}), $$ for any integer $r\ge 2$. Here, $$ C_{r}=\frac{1}{(2^r-1)!} \prod_{p\ge 2}\left( \left(1-\frac{1}{p}\right)^{2^r} \left(\sum_{α\ge 0} \frac{(α+1)^r}{p^α}\right)\right). $$
description: 8 pages, revised
On thermality of CFT eigenstates
Creators: name: Basu, Pallab
name: Das, Diptarka
name: Datta, Shouvik
name: Pal, Sridip
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The Eigenstate Thermalization Hypothesis (ETH) provides a way to understand how an isolated quantum mechanical system can be approximated by a thermal density matrix. We find a class of operators in (1+1)-$d$ conformal field theories, consisting of quasi-primaries of the identity module, which satisfy the hypothesis only at the leading order in large central charge. In the context of subsystem ETH, this plays a role in the deviation of the reduced density matrices, corresponding to a finite energy density eigenstate from its hypothesized thermal approximation. The universal deviation in terms of the square of the trace-square distance goes as the 8th power of the subsystem fraction and is suppressed by powers of inverse central charge ($c$). Furthermore, the non-universal deviations from subsystem ETH are found to be proportional to the heavy-light-heavy structure constants which are typically exponentially suppressed in $\sqrt{h/c}$, where $h$ is the conformal scaling dimension of the finite energy density state. We also examine the effects of the leading finite size corrections.
description: 25 pages, 2 figures; published version with a few references added
Qualitative analysis of dynamic equations on time scales
Creators: name: Abbas, Syed
Publisher: name: arXiv
Year: 2017
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 34N05, 26E70, 34A12

description: In this article, we establish the Picard-Lindelof theorem and approximating results for dynamic equations on time scale. We present a simple proof for the existence and uniqueness of the solution. The proof is produced by using convergence and Weierstrass M-test. Furthermore, we show that the Lispchitz condition is not necessary for uniqueness. The existence of epsilon-approximate solution is established under suitable assumptions. Moreover, we study the approximate solution of the dynamic equation with delay by studying the solution of the corresponding dynamic equation with piecewise constant argument. We show that the exponential stability is preserved in such approximations.
description: 13 pages
A Polyethylene-B4C based concrete for enhanced neutron shielding at neutron research facilities
Creators: name: DiJulio, D. D.
name: Cooper-Jensen, C. P.
name: Perrey, H.
name: Fissum, K.
name: Rofors, E.
name: Scherzinger, J.
name: Bentley, P. M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: We present the development of a specialized concrete for neutron shielding at neutron research facilities, based on the addition of hydrogen atoms in the form of polyethylene and also B$_{4}$C for enhancing the neutron capture properties of the concrete. We show information on the mechanical properties of the concrete and the neutronics, in particular it's relevance to modern spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden. The new concrete exhibits a 15% lower mass density, a compressible strength of 50% relative to a standard concrete and a significant increase in performance of shielding against MeV neutrons and lower energies. The concrete could find application at the ESS in for example common shielding components, individual beamline shielding and instrument caves. Initial neutronic tests of the concrete, carried out at Lund University, have also verified the performance in the MeV neutron energy range and the results are presented.
description: This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Kesten's bound for sub-exponential densities on the real line and its multi-dimensional analogues
Creators: name: Finkelshtein, Dmitri
name: Tkachov, Pasha
Publisher: name: arXiv
Year: 2017
Subjects: subject: Probability (math.PR)
subject: Analysis of PDEs (math.AP)
subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 60E05, 45M05, 62E20

description: We study the tail asymptotic of sub-exponential probability densities on the real line. Namely, we show that the n-fold convolution of a sub-exponential probability density on the real line is asymptotically equivalent to this density times n. We prove Kesten's bound, which gives a uniform in n estimate of the n-fold convolution by the tail of the density. We also introduce a class of regular sub-exponential functions and use it to find an analogue of Kesten's bound for functions on $\mathbb{R}^d$. The results are applied for the study of the fundamental solution to a nonlocal heat-equation.
description: The paper contains materials which were previously included to the first version of the publication arXiv:1611.09329 [math.AP]. A condensed version is to appear in Adv.Appl.Prob
Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs II: Properties of 11 T-dwarfs
Creators: name: Line, Michael R.
name: Marley, Mark S.
name: Liu, Michael C.
name: Burningham, Ben
name: Morley, Caroline V.
name: Hinkel, Natalie R.
name: Teske, Johanna
name: Fortney, Jonathan J.
name: Lupu, Roxana
name: Freedman, Richard
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Brown dwarf spectra are rich in information revealing of the chemical and physical processes operating in their atmospheres. We apply a recently developed atmospheric retrieval tool to an ensemble of late T-dwarf (600-800K) near infrared spectra. With these spectra we are able to place direct constraints the molecular abundances of H$_2$O, CH$_4$, CO, CO$_2$, NH$_3$, H$_2$S, and Na+K, gravity, thermal structure (and effective temperature), photometric radius, and cloud optical depths. We find that ammonia, water, methane, and the alkali metals are present and well constrained in all 11 objects. From the abundance constraints we find no significant trend in the water, methane, or ammonia abundances with temperature, but find a very strong ($>$25$σ$) increasing trend in the alkali metal abundances with effective temperature, indicative of alkali rainout. We also find little evidence for optically thick clouds. With the methane and water abundances, we derive the intrinsic atmospheric metallicity and carbon-to-oxygen ratios. We find in our sample, that metallicities are typically sub solar and carbon-to-oxygen ratios are somewhat super solar, different than expectations from the local stellar population. We also find that the retrieved vertical thermal profiles are consistent with radiative equilibrium over the photospheric regions. Finally, we find that our retrieved effective temperatures are lower than previous inferences for some objects and that our radii are larger than expectations from evolutionary models, possibly indicative of un-resolved binaries. This investigation and methodology represents a paradigm in linking spectra to the determination of the fundamental chemical and physical processes governing cool brown dwarf atmospheres.
description: Accepted ApJ. Supplemental material including full posteriors will be included through the link in the published ApJ article
Finite element error analysis for measure-valued optimal control problems governed by a 1D wave equation with variable coefficients
Creators: name: Trautmann, Philip
name: Vexler, Boris
name: Zlotnik, Alexander
Publisher: name: arXiv
Year: 2017
Subjects: subject: Numerical Analysis (math.NA)
subject: Optimization and Control (math.OC)
subject: FOS: Mathematics
subject: Primary: 65M60, 49K20, 49M05, 49M25, 49M29, Secondary: 35L05

description: This work is concerned with the optimal control problems governed by a 1D wave equation with variable coefficients and the control spaces $\mathcal M_T$ of either measure-valued functions $L_{w^*}^2(I,\mathcal M(Ω))$ or vector measures $\mathcal M(Ω,L^2(I))$. The cost functional involves the standard quadratic tracking terms and the regularization term $α\|u\|_{\mathcal M_T}$ with $α>0$. We construct and study three-level in time bilinear finite element discretizations for this class of problems. The main focus lies on the derivation of error estimates for the optimal state variable and the error measured in the cost functional. The analysis is mainly based on some previous results of the authors. The numerical results are included.
description: 39 pages, 6 figures
Phase Transitions, Inhomogeneous Horizons and Second-Order Hydrodynamics
Creators: name: Attems, Maximilian
name: Bea, Yago
name: Casalderrey-Solana, Jorge
name: Mateos, David
name: Triana, Miquel
name: Zilhao, Miguel
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We use holography to study the spinodal instability of a four-dimensional, strongly-coupled gauge theory with a first-order thermal phase transition. We place the theory on a cylinder in a set of homogeneous, unstable initial states. The dual gravity configurations are black branes afflicted by a Gregory-Laflamme instability. We numerically evolve Einstein's equations to follow the instability until the system settles down to a stationary, inhomogeneous black brane. The dual gauge theory states have constant temperature but non-constant energy density. We show that the time evolution of the instability and the final states are accurately described by second-order hydrodynamics. In the static limit, the latter reduces to a single, second-order, non-linear differential equation from which the inhomogeneous final states can be derived.
description: 11 pages, 6 figures. Matches published version in JHEP
On vanishing near corners of transmission eigenfunctions
Creators: name: Blåsten, Eemeli
name: Liu, Hongyu
Publisher: name: arXiv
Year: 2017
Subjects: subject: Analysis of PDEs (math.AP)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: 35P25, 58J50, 35R30, 81V80

description: Let $Ω$ be a bounded domain in $\mathbb{R}^n$, $n\geq 2$, and $V\in L^\infty(Ω)$ be a potential function. Consider the following transmission eigenvalue problem for nontrivial $v, w\in L^2(Ω)$ and $k\in\mathbb{R}_+$, \[(Δ+k^2)v= 0 \quad \text{in } Ω,\] \[(Δ+k^2(1+V))w= 0 \quad \text{in } Ω,\] \[w-v \in H^2_0(Ω), \quad \lVert v \rVert_{L^2(Ω)}=1. \] We show that the transmission eigenfunctions $v$ and $w$ carry the geometric information of $\mathrm{supp}(V)$. Indeed, it is proved that $v$ and $w$ vanish near a corner point on $\partial Ω$ in a generic situation where the corner possesses an interior angle less than $π$ and the potential function $V$ does not vanish at the corner point. This is the first quantitative result concerning the intrinsic property of transmission eigenfunctions and enriches the classical spectral theory for Dirichlet/Neumann Laplacian. We also discuss its implications to inverse scattering theory and invisibility.
description: 17 pages, addendum at arxiv:1710.08089
Tidal deformation of a slowly rotating material body: Interior metric and Love numbers
Creators: name: Landry, Philippe
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The metric outside a compact body deformed by a quadrupolar tidal field is universal up to its Love numbers, constants which encode the tidal response's dependence on the body's internal structure. For a non-rotating body, the deformed external geometry is characterized by the familiar gravitational Love numbers $K_2^{\text{el}}$ and $K_2^{\text{mag}}$. For a slowly rotating body, these must be supplemented by rotational-tidal Love numbers, which measure the response to couplings between the body's spin and the external tidal field. By integrating the interior field equations, I find that the response of a barotropic perfect fluid to spin-coupled tidal perturbations is described by two rotational-tidal Love numbers, which I calculate explicitly for polytropes. Two other rotational-tidal Love numbers identified in prior work are found to have a fixed, universal value for all barotropes. Equipped with the complete interior solution, I calculate the amplitude of the time-varying internal currents induced by the gravitomagnetic part of the tidal field. For a typical neutron star in an equal-mass binary system, the size of the equatorial velocity perturbation is on the order of kilometers per second.
description: 19 pages, 7 figures; updated figures and corrected typos; matches the published version
Blown-up intersection cohomology
Creators: name: Chataur, David
name: Saralegi-Aranguren, Martintxo
name: Tanré, Daniel
Publisher: name: arXiv
Year: 2017
Subjects: subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 55N33, 57N80, 55S05

description: In previous works, we have introduced the blown-up intersection cohomology and used it to extend Sullivan's minimal models theory to the framework of pseudomanifolds, and to give a positive answer to a conjecture of M. Goresky and W. Pardon on Steenrod squares in intersection homology. In this paper, we establish the main properties of this cohomology. One of its major feature is the existence of cap and cup products for any filtered space and any commutative ring of coefficients, at the cochain level. Moreover, we show that each stratified map induces an homomorphism between the blown-up intersection cohomologies, compatible with the cup and cap products. We prove also its topological invariance in the case of a pseudomanifold with no codimension one strata. Finally, we compare it with the intersection cohomology studied by G. Friedman and J.E. McClure. A great part of our results involves general perversities, defined independently on each stratum, and a tame intersection homology adapted to large perversities.
description: Version 1 of Arxiv 1603.08773 had been split in two parts. This is the first part (corresponding to Parts I and II of 1603.08773v1) substantially revised. The study of stratified maps in cohomology and the proof of the topological invariance have been added
Robust Calibration of Radio Interferometers in Non-Gaussian Environment
Creators: name: Ollier, Virginie
name: Korso, Mohammed Nabil El
name: Boyer, Rémy
name: Larzabal, Pascal
name: Pesavento, Marius
Publisher: name: arXiv
Year: 2016
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: The development of new phased array systems in radio astronomy, as the low frequency array (LOFAR) and the square kilometre array (SKA), formed of a large number of small and flexible elementary antennas, has led to significant challenges. Among them, model calibration is a crucial step in order to provide accurate and thus meaningful images and requires the estimation of all the perturbation effects introduced along the signal propagation path, for a specific source direction and antenna position. Usually, it is common to perform model calibration using the a priori knowledge regarding a small number of known strong calibrator sources but under the assumption of Gaussianity of the noise. Nevertheless, observations in the context of radio astronomy are known to be affected by the presence of outliers which are due to several causes, e.g., weak non-calibrator sources or man made radio frequency interferences. Consequently, the classical Gaussian noise assumption is violated leading to severe degradation in performances. In order to take into account the outlier effects, we assume that the noise follows a spherically invariant random distribution. Based on this modeling, a robust calibration algorithm is presented in this paper. More precisely, this new scheme is based on the design of an iterative relaxed concentrated maximum likelihood estimation procedure which allows to obtain closed-form expressions for the unknown parameters with a reasonable computational cost. This is of importance as the number of estimated parameters depends on the number of antenna elements, which is large for the new generation of radio interferometers. Numerical simulations reveal that the proposed algorithm outperforms the state-of-the-art calibration techniques.
PLANO DE CONTROLADORIA CIÊNCIAS CONTÁBEIS
Creators: name: Cícero Pereira da SILVA
name: Caroline Moreira Ribeiro SANTOS
Publisher: name: Zenodo
Year: 2024
Subjects: Plano de controladoria
Ciências contábeis
Geração de emprego

description: RESUMO

 

Introdução: O modelo de gestão é o método adotado no processo produtivo, de forma que organiza suas atividades e seus recursos com a implantação de normas e regras, a fim de estimular o crescimento, visando demonstrar seus objetivos, valores, visão e missão. Objetivos: Implementar políticas de Geração de Emprego e Renda; Contribuir para o desenvolvimento econômico social do Município de Pinhais; Apoiar e divulgar o potencial turístico local; Desenvolver o sistema de agricultura urbana e abastecimento; Apoiar as demais Secretarias na captação de recursos externos. Metodologia. Pesquisa bibliográfica mediante Revisão de Literatura. Resultados: O Projeto de Controladoria, veio aprofundar nossos conhecimentos no processo de abertura e planejamento estratégico de uma empresa, independente da atividade que exerça. Conclusão: Nesta atividade adquirimos o entendimento de como deve ser feito o processo desde a abertura até a produção final, bem como auxiliar na tomada de decisões, que visem melhorar desempenhos.
A physiology--based parametric imaging method for FDG--PET data
Creators: name: Scussolini, Mara
name: Garbarino, Sara
name: Sambuceti, Gianmario
name: Caviglia, Giacomo
name: Piana, Michele
Publisher: name: arXiv
Year: 2017
Subjects: subject: Numerical Analysis (math.NA)
subject: Medical Physics (physics.med-ph)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: FOS: Biological sciences
subject: 65R32, 68U10

description: Parametric imaging is a compartmental approach that processes nuclear imaging data to estimate the spatial distribution of the kinetic parameters governing tracer flow. The present paper proposes a novel and efficient computational method for parametric imaging which is potentially applicable to several compartmental models of diverse complexity and which is effective in the determination of the parametric maps of all kinetic coefficients. We consider applications to [{18}F]-fluorodeoxyglucose Positron Emission Tomography (FDG-PET) data and analyze the two-compartment catenary model describing the standard FDG metabolization by an homogeneous tissue and the three-compartment non-catenary model representing the renal physiology. We show uniqueness theorems for both models. The proposed imaging method starts from the reconstructed FDG-PET images of tracer concentration and preliminarily applies image processing algorithms for noise reduction and image segmentation. The optimization procedure solves pixelwise the non-linear inverse problem of determining the kinetic parameters from dynamic concentration data through a regularized Gauss-Newton iterative algorithm. The reliability of the method is validated against synthetic data, for the two-compartment system, and experimental real data of murine models, for the renal three-compartment system.
Psychometric properties of the French Hot Flash Related Daily Interference Scale (HFRDIS)
Creators: name: Cavadias, I.
name: Rouzier, R.
name: Milder, M.
name: Bonneau, C.
name: Mullaert, J.
name: Hequet, D.
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Medicine
subject: Biotechnology
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Science Policy

description: Hot flashes are one of the major symptoms of climacteric syndrome. Despite the high prevalence of these symptoms, few questionnaires assessing the impact of hot flashes on quality of life have been validated. The aim of this study was to validate a French version of the Hot Flash Related Daily Interference Scale (HFRDIS) in a sample of French women. In this prospective study, data were obtained from two groups of women aged between 40 and 60 years from both women without breast cancer and women under hormone therapy for breast cancer between March 2021 and February 2022. Translation was made by an official English–French translator using the forward–backward method. One hundred and sixty-seven women completed the HFRDIS questionnaire. The scree plots confirmed unidimensional structure. Cronbach’s α coefficient was 0.92 [0.90–0.94] similar to the original version. The intra-class correlation coefficients of each item ranged between 0.58 and 0.71 Concordance of the scores of each item with those obtained during the validation of the original version of the HFRDIS was confirmed. The validation results show that the French version of the HFRDIS questionnaire is a valid tool to evaluate the impact of hot flashes on the daily life activities of patients.
K2 Ultracool Dwarfs Survey II: The White Light Flare Rate of Young Brown Dwarfs
Creators: name: Gizis, John E.
name: Paudel, Rishi R.
name: Mullan, Dermott
name: Schmidt, Sarah J.
name: Burgasser, Adam J.
name: Williams, Peter K. G.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We use Kepler K2 Campaign 4 short-cadence (one-minute) photometry to measure white light flares in the young, moving group brown dwarfs 2MASS J03350208+2342356 (2M0335+23) and 2MASS J03552337+1133437 (2M0355+11), and report on long-cadence (thirty-minute) photometry of a superflare in the Pleiades M8 brown dwarf CFHT-PL-17. The rotation period (5.24 hr) and projected rotational velocity ($45$ km s$^{-1}$) confirm 2M0335+23 is inflated ($R \ge 0.20 R_\odot$) as predicted for a $0.06M_\odot$, 26-Myr old brown dwarf $β$Pic moving group member. We detect 22 white light flares on 2M0335+23. The flare frequency distribution follows a power-law distribution with slope $-α= -1.8 \pm 0.2$ over the range $10^{31}$ to $10^{33}$ erg. This slope is similar to that observed in the Sun and warmer flare stars, and is consistent with lower energy flares in previous work on M6-M8 very-low-mass stars; taken the two datasets together, the flare frequency distribution for ultracool dwarfs is a power law over 4.3 orders of magnitude. The superflare ($2.6\times10^{34}$ erg) on CFHT-PL-17 shows higher energy flares are possible. We detect no flares down to a limit of $2 \times 10^{30}$ erg in the nearby L$5γ$ AB Dor Moving Group brown dwarf 2M0355+11, consistent with the view that fast magnetic reconnection is suppressed in cool atmospheres. We discuss two multi-peaked flares observed in 2M0335+23, and argue that these complex flares can be understood as sympathetic flares, in which a fast-mode MHD waves similar to EUV waves in the Sun trigger magnetic reconnection in different active regions.
description: Accepted version, The Astrophysical Journal
What is health technology assessment?
Creators: name: Harvey, Elizabeth
Publisher: name: figshare
Year: 2022
Subjects: subject: 111504 Pharmaceutical Sciences
subject: FOS: Clinical medicine

description: There is a need for consistent use of plain language communications to support patient involvement in health economics and outcomes research (HEOR). This summary provides a plain language explanation of the purpose of and approaches to health technology assessment from a global perspective.
СРАВНИТЕЛЬНЫЙ АНАЛИЗ ПОСЛЕОПЕРАЦИОННЫХ ОСЛОЖНЕНИЙ АЛЛОГЕРНИОПЛАСТИКИ
Creators: name: Сувонов, Мадаминжон
name: Шоназаров, Искандар
Publisher: name: Zenodo
Year: 2025

description: Р.Ш.Шайморданов с соавторами (2014) ввели термин «клинически значимые скопления серозной жидкости в ране (КЗС)». К ним отнесли любые анэхогенные участки в слоях послеоперационной раны, которые по данным УЗИ, превышали в одном из трех размеров (длина, ширина и высота) 20 мм. Отвечая на вопрос, что называть «клинически незначимыми серомами», она считали, что это скопления жидкости, не вызывающие субъективных ощущений у пациентов. Подобрать объективный критерий для определения «клинически значимой и незначимой серомы» очень сложно, поскольку ни ее объем, ни размеры не могут иметь принципиального значения.
The best constants in the Multiple Khintchine Inequality
Creators: name: Núñez-Alarcón, Daniel
name: Serrano-Rodríguez, Diana M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 11Y60, 46G25

description: In this work we provide the best constants of the multiple Khintchine inequality. This allows us, among other results, to obtain the best constants of the mixed $\left( \ell_{\frac{p}{p-1}},\ell_{2}\right) $-Littlewood inequality, thus ending completely a work started by Pellegrino in \cite{pell}.
description: 16 pages