cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Gas depletion in cluster galaxies depends strongly on their internal structure
Creators: name: Zhang, Wei
name: Li, Cheng
name: Kauffmann, Guinevere
name: Xiao, Ting
Publisher: name: arXiv
Year: 2012
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We analyze galaxies in 300 nearby groups and clusters identified in the Sloan Digital Sky Survey using a photometric gas mass indicator that is useful for estimating the degree to which the interstellar medium of a cluster galaxy has been depleted. We study the radial dependence of inferred gas mass fractions for galaxies of different stellar masses and stellar surface densities. At fixed clustercentric distance and at fixed stellar mass, lower density galaxies are more strongly depleted of their gas than higher density galaxies. An analysis of depletion trends in the two-dimensional plane of stellar mass $M_*$ and stellar mass surface density $μ_*$ reveals that gas depletion at fixed clustercentric radius is much more sensitive to the density of a galaxy than to its mass. We suggest that low density galaxies are more easily depleted of their gas, because they are more easily affected by ram-pressure and/or tidal forces. We also look at the dependence of our gas fraction/radius relations on the velocity dispersion of the cluster, finding no clear systematic trend.
description: 9 pages, 8 figures, accepted for publication in MNRAS
title: Development of stabilized FK506 binding protein 51 variants & generation of ligand-based affinity chromatography beads
Creators: name: Charalampidou, Anna
Publisher: name: UNSPECIFIED
Year: 2023

description: The presented work covers two projects: the stabilization of the F67-out conformation for the FK506 binding protein 51 (FKBP51) and the generation of a ligand-based affinity matrix. FKBP51 is a prominent example of a transient binding pocket that is key to achieve selectivity in ligand development. In FKBP51, the transient binding pocket is characterized by a rearrangement of residue F67 outward from the binding pocket, also called the F67-out conformation. The aim was to generate protein constructs with a stabilized F67-out conformation to identify hits in screenings targeting this specific protein conformation. By rational protein engineering, I succeeded to generate FKBP51 variants with a stabilized F67-out conformation. Techniques used to covalently fix the conformation in this out conformation include crosslinking approaches such as photocrosslinking, click chemistry, or cysteine-directed crosslinking, as well as chemical protein synthesis. The obtained variants showed improvement in binding affinity to a conformationally selective ligand tracer in the fluorescence polarization (FP) assay. Overall, the FKBP51FK1 F67C/K60C variant with a disulfide bridge emerged as the most suitable variant for fragment screening. The reasons for this are the facile production of the protein variant in high quantity and purity, the improvement in binding affinity for conformationally selective ligands, and the possibility of crystallizing the protein in its apo form in a F67-out-like conformation. Initial fragment-based screening by thermoshift assay followed by FP assay resulted in promising hits with an amine-substituted quinoline and isoquinoline-core structure. This is the first step on a new path to identifying new lead structures. In addition, a ligand-based affinity chromatography matrix was generated. This should allow FKBP51 to be enriched from complex biological mixtures as well as identify new interaction partners and/or off-targets. In this work, four ligands were successfully immobilized and tested, with loading and elution conditions optimized. Two systems were found to be suitable for the enrichment of FKBP51 from complex biological mixtures. Either SAFit1 is directly immobilized and elution takes place under harsh conditions, or a SAFit1 analog with low affinity (here called SAFit-LA) is immobilized so that elution can be performed competitively with SAFit1.
Finding viable Models in SUSY Parameter Spaces with Signal Specific Discovery Potential
Creators: name: Burgess, Thomas
name: Lindroos, Jan Øye
name: Lipniacka, Anna
name: Sandaker, Heidi
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Recent results from ATLAS gives a Higgs mass of 125.5 GeV, further constrain already highly constrained supersymmetric models such as pMSSM or CMSSM/mSUGRA. Finding potentially discoverable and non-excluded regions of model parameter space is becoming increasingly difficult. Several groups have invested large effort in studying the consequences of Higgs mass bounds, upper limits on rare $B$-meson decays, and limits on relic dark matter density on constrained models, aiming at predicting superpartner masses, and establishing likelihood of SUSY models compared to that of the Standard Model vis-á-vis experimental data. In this paper a framework for efficient search for discoverable, non-excluded regions of different SUSY spaces giving specific experimental signature of interest is presented. The method employs an improved Markov Chain Monte Carlo (MCMC) scheme exploiting an iteratively updated likelihood function to guide search for viable models. Existing experimental and theoretical bounds as well as the LHC discovery potential are taken into account. This includes recent bounds on relic dark matter density, the Higgs sector and rare $B$-mesons decays. A clustering algorithm is applied to classify selected models according to expected phenomenology enabling automated choice of experimental benchmarks and regions to be used for optimizing searches. The aim is to provide experimentalist with a viable tool helping to target experimental signatures to search for, once a class of models of interest is established. As an example a search for viable CMSSM models with $τ$-lepton signatures observable with the 2012 LHC data set is presented. In the search 105209 unique models were probed. From these, ten reference benchmark points covering different ranges of phenomenological observables at the LHC were selected.
Applied Materials dimension factory simulation
Creators: name: Elimbi Moudio, Agnes
Publisher: name: The University of Texas at Austin
Year: 2022
Subjects: Discrete event simulation

description: Applied Materials launched a CMP Manufacturing Line Process in 2020. Due to the complex nature of the process and the investment need, the company must be careful when they want to implement changes in their system. Discrete Event Simulation Models offer the possibility to test hypotheses in a virtual environment before implementing them in real life. In this document, we created a discrete-event simulation to model the CMP manufacturing line using the modeling tool FlexSim. During the model building process, the most crucial aspect was implementing the process times for printing and metrology tasks, the personnel’s timetable, and the logic handling printing and metrology tasks. We used the model to evaluate the utilization rates of the equipment at the baseline level and when we double the capacity. In addition, we observe the system's behavior for different throughput targets under different shift systems. We concluded that different shift systems lead to increased production; however, this must be balanced with the increased system stay time. Finally, we observed the effect of increasing the number of printers in use for different production levels.
“The Wisdom of the Egyptians”: Revisiting Jan Assmann’s Reading of the Early Modern Reception of Moses
Creators: name: Feingold, Mordechai
Publisher: name: Aegyptiaca. Journal of the History of Reception of Ancient Egypt
Year: 2019

description: Aegyptiaca. Journal of the History of Reception of Ancient Egypt, Nr. 4 (2019): Aegyptiaca. Journal of the History of Reception of Ancient Egypt
Botanic Gardens Micropropagation News, Volume 1, Issue 6.
Creators: name: Royal Botanic Gardens, Kew
Publisher: name: Royal Botanic Gardens, Kew in association with Botanic Gardens Conservation International
Year: 1993
Subjects: Limonium
Micropropagation
Endangered plants
In vitro culture
Astrophytum capricorne
In vitro propagation
Dyclia macedoi

description: Contents: [Editorial] / Michael F. Fay. Micropropagation of Dyckia macedoi – an endangered Brazilian bromeliad / H. Mercier and G. Kerbauy. Preliminary remarks on the micropropagation of threatened Limonium species (Plumbaginaceae) / M.D. Lledó et al. Micropropagation of Astrophytum capricorne, an endangered species of cactus from N.E. Mexico / E. Cárdenas et al. Recent references.
description: Kew, UK
“Out of the Iron Furnace”. Exodus, Death, and the Reception History of Freedom
Creators: name: Schaper, Joachim
Publisher: name: Aegyptiaca. Journal of the History of Reception of Ancient Egypt
Year: 2019

description: Aegyptiaca. Journal of the History of Reception of Ancient Egypt, Nr. 4 (2019): Aegyptiaca. Journal of the History of Reception of Ancient Egypt
Three-dimensional Bondi-Metzner-Sachs invariant two-dimensional field theories as the flat limit of Liouville theory
Creators: name: Barnich, Glenn
name: Gomberoff, Andrés
name: González, Hernán A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In the gravitational context, Liouville theory is the two-dimensional conformal field theory that controls the boundary dynamics of asymptotically AdS_3 spacetimes at the classical level. By taking a suitable limit of the coupling constants of the Hamiltonian formulation of Liouville, we construct and analyze a BMS_3 invariant two-dimensional field theory that is likely to control the boundary dynamics at null infinity of three dimensional asymptotically flat gravity.
description: 14 pages, no figures, Latex file; v2 Title has been changed, minimal changes and corrections
Implications of hydrodynamic fluctuations on the minimum shear viscosity of the dilute Fermi gas at unitarity
Creators: name: Romatschke, Paul
name: Young, Ryan Edward
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We confirm and expand on work by Chafin and Schaefer on hydrodynamic fluctuations in the unitary Fermi gas. Using the result for the equation of state from a recent MIT experiment, we derive lower bounds for η/n and η/s as a function of temperature. Re-analyzing recent quantum Monte Carlo data for the shear-viscosity spectral function we point out a possible resolution for the tension between the viscosity bound η/n> 0.3 from Chafin and Schaefer and the quantum Monte Carlo results η/n<0.2$ from Wlazlowski et al. near the critical temperature
description: 14 pages plus appendices; v2: major revisions including new introductory material on classical versus fluctuating hydrodynamics
Nonclassical photon pair production in a voltage-biased Josephson junction
Creators: name: Leppäkangas, Juha
name: Johansson, Göran
name: Marthaler, Michael
name: Fogelström, Mikael
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We investigate electromagnetic radiation emitted by a small voltage-biased Josephson junction connected to a superconducting transmission line. At frequencies below the well known emission peak at the Josephson frequency (2eV/h), extra radiation is triggered by quantum fluctuations in the electromagnetic environment. For weak tunneling couplings and typical ohmic transmission lines, the corresponding photon flux spectrum is symmetric around half the Josephson frequency, indicating that the photons are predominately created in pairs. By establishing an input-output formalism for the microwave field in the transmission line, we give further evidence for this nonclassical photon pair production, demonstrating that it violates the classical Cauchy-Schwarz inequality for two-mode flux cross correlations. In connection to recent experiments, we also consider a stepped transmission line, where resonances increase the signal-to-noise ratio.
description: 5 pages, 2 figures. This version accepted in Physical Review Letters
Violation of the Robertson-Schrödinger uncertainty principle and non-commutative quantum mechanics
Creators: name: Bastos, Catarina
name: Bertolami, Orfeu
name: Dias, Nuno Costa
name: Prata, João Nuno
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We show that a possible violation of the Robertson-Schrödinger uncertainty principle may signal the existence of a deformation of the Heisenberg-Weyl algebra. More precisely, we prove that any Gaussian in phase-space (even if it violates the Robertson-Schrödinger uncertainty principle) is always a quantum state of an appropriate non-commutative extension of quantum mechanics. Conversely, all canonical non-commutative extensions of quantum mechanics display states that violate the Robertson-Schrödinger uncertainty principle.
description: 5 pages, revtex4, To match version published in Physical Review D 86, 105030 (2012)
Isospin Non-Conservation in $sd$-Shell Nuclei
Creators: name: Lam, Yi Hua
name: Smirnova, Nadezda A.
name: Caurier, Etienne
Publisher: name: arXiv
Year: 2012
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The question of isospin-symmetry breaking in nuclei of the $sd$ shell is addressed. We propose a new global parameterization of the isospin-nonconserving (INC) shell-model Hamiltonian which accurately describes experimentally known isobaric mass splittings. The isospin-symmetry violating part of the Hamiltonian consists of the Coulomb interaction and effective charge-dependent forces of nuclear origin. Particular attention has been paid to the effect of the short-range correlations. The behavior of $b$ and $c$ coefficients of the isobaric-mass-multiplet equation (IMME) is explored in detail. In particular, a high-precision numerical description of the staggering effect is proposed and contribution of the charge-dependent forces to the nuclear pairing is discussed. The Hamiltonian is applied to the study of the IMME beyond a quadratic form in the A=32 quintet, as well as to calculation of nuclear structure corrections to superallowed $0^+ \to 0^+$ Fermi $β$ decay, and to amplitudes of Fermi transitions to non-analogue states in sd-shell nuclei.
description: updated version: 30 pages, 16 figures
Security, Governance and Development Beyond the Pavement: A Quantitative Assessment of the Afghan Local Police
Creators: name: Cohen, Alison
Publisher: name: Stanford Digital Repository
Year: 2023
Subjects: Afghanistan, Local Security, Economic Development, Afghan Local Police, Local Governance

description: The Afghan Local Police (ALP) was the most robust local defense mobilization effort used in the War in Afghanistan. Funded by the United States and under the purview of the Afghan government, The ALP program aimed at fostering self-defense among local communities while reinforcing the authority of traditional governance institutions. Active from 2010-2020, the program amassed a force of 34,000 men, composed over 8% of the Afghan National Security force, cost the US government $1.2 billion, and even gained a reputation as the American “exit strategy”. Still, little quantitative work has been done to assess how the Afghan Local Police lived up to its ambitious goals of establishing sustainable political order in the countryside. Moreover, only anecdotal evidence provides insight into the ALP's impact on the lives of individual villagers. In this thesis, I build a theory integrating the Afghan Local Police with governance, security, and economic development outcomes. To explore this theory, I measure variables such as nightlight radiance, (a proxy for economic development) and survey data on support for the local government and belief in the local government’s ability to maintain security. I find that, despite originally aspiring to be a crucial part of the local governance and security strategy, the Afghan Local Police failed to correlate with any of these outcomes. I conclude by contextualizing these findings in the broader War in Afghanistan, highlighting how the international coalition's disregard for rural areas contributed to the Taliban's eventual takeover.
Analysis and optimization of a distributed propulsion system for a regional transport aircraft
Creators: name: Mateo-Gabín, Andrés
name: Wagenaar, Thomas
name: Mancini, Simone
name: Florenciano Merino, Juan L.
name: Lanzan Ferran, Sven A.
Publisher: name: Zenodo
Year: 2024

description: AIRBUS, dedicated partner to the HERA project,  prepared and presented the work conducted on "Analysis and optimization of a distributed propulsion system for a regional transport aircraft" at the ECCOMASS conference (https://www.eccomas.org/2022/06/16/eccomas-congress-2024-announcement/). The presentation includes results related to the HERA project.  They include an analysis and an optimization tool for aircraft design, and so far, they have been successfully coupled with a mid-fidelity aerodynamic solver, the DUST. The attached file is a presentation of these preliminary results, where the above-mentioned tool has been used to maximize the efficiency of a wing by modifying its shape and the position of the propellers along the span.
Beurling's criterion and extremal metrics for Fuglede modulus
Creators: name: Badger, Matthew
Publisher: name: arXiv
Year: 2012
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 31B15 (Primary) 28A33, 49K27 (Secondary)

description: We formulate a necessary and sufficient condition for an admissible metric to be extremal for the Fuglede p-modulus of a system of measures. When p=2, this characterization generalizes Beurling's criterion, a sufficient condition for an admissible metric to be extremal for the extremal length of a planar curve family. In addition, we prove that every non-negative Borel function in R^n with positive and finite p-norm is extremal for the p-modulus of some curve family.
description: 12 pages, 2 figures (version 4: minor improvements, updated numbering and corrected typos, final version)
Mordell-Weil ranks of families of elliptic curves associated to Pythagorean triples
Creators: name: Naskręcki, Bartosz
Publisher: name: arXiv
Year: 2012
Subjects: subject: Number Theory (math.NT)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14H52, 11G05, 11D25, 11D45

description: We study the family of elliptic curves $y^2=x(x-a^2)(x-b^2)$ parametrized by Pythagorean triples $(a,b,c)$. We prove that for a generic triple the lower bound of the rank of the Mordell-Weil group over $\mathbb{Q}$ is 1, and for some explicitly given infinite family the rank is 2. To each family we attach an elliptic surface fibered over the projective line. We show that the lower bounds for the rank are optimal, in the sense that for each generic fiber of such an elliptic surface its corresponding Mordell-Weil group over the function field $\mathbb{Q}(t)$ has rank 1 or 2, respectively. In order to prove this, we compute the characteristic polynomials of the Frobenius automorphisms acting on the second $\ell$-adic cohomology groups attached to elliptic surfaces of Kodaira dimensions 0 and 1.
description: 19 pages
Matrices that commute with their derivative. On a letter from Schur to Wielandt
Creators: name: Holtz, Olga
name: Mehrmann, Volker
name: Schneider, Hans
Publisher: name: arXiv
Year: 2012
Subjects: subject: Rings and Algebras (math.RA)
subject: History and Overview (math.HO)
subject: FOS: Mathematics
subject: 15A54, 15-03, 15A27, 15A24, 15A21, 01A60, 01A70

description: We examine when a matrix whose elements are differentiable functions in one variable commutes with its derivative. This problem was discussed in a letter from Issai Schur to Helmut Wielandt written in 1934, which we found in Wielandt's Nachlass. We present this letter and its translation into English. The topic was rediscovered later and partial results were proved. However, there are many subtle observations in Schur's letter which were not obtained in later years. Using an algebraic setting, we put these into perspective and extend them in several directions. We present in detail the relationship between several conditions mentioned in Schur's letter and we focus in particular on the characterization of matrices called Type 1 by Schur. We also present several examples that demonstrate Schur's observations.
description: 21 pages, 1 facsimile, some inaccuracies corrected, historical comments and acknowledgments added; final version to appear in Linear Algebra and its Applications
Measurement error in two-stage analyses, with application to air pollution epidemiology
Creators: name: Szpiro, Adam A.
name: Paciorek, Christopher J.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Public health researchers often estimate health effects of exposures (e.g., pollution, diet, lifestyle) that cannot be directly measured for study subjects. A common strategy in environmental epidemiology is to use a first-stage (exposure) model to estimate the exposure based on covariates and/or spatio-temporal proximity and to use predictions from the exposure model as the covariate of interest in the second-stage (health) model. This induces a complex form of measurement error. We propose an analytical framework and methodology that is robust to misspecification of the first-stage model and provides valid inference for the second-stage model parameter of interest. We decompose the measurement error into components analogous to classical and Berkson error and characterize properties of the estimator in the second-stage model if the first-stage model predictions are plugged in without correction. Specifically, we derive conditions for compatibility between the first- and second-stage models that guarantee consistency (and have direct and important real-world design implications), and we derive an asymptotic estimate of finite-sample bias when the compatibility conditions are satisfied. We propose a methodology that (1) corrects for finite-sample bias and (2) correctly estimates standard errors. We demonstrate the utility of our methodology in simulations and an example from air pollution epidemiology.
description: 35 pages, 4 figures, 2 tables
A General Theory of Turbulent Fragmentation
Creators: name: Hopkins, Philip F.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We develop an analytic framework to understand fragmentation in turbulent, self-gravitating media. Previously, we showed some properties of turbulence can be predicted with the excursion-set formalism. Here, we generalize to fully time-dependent gravo-turbulent fragmentation & collapse. We show that turbulent systems are always gravitationally unstable (in a probabilistic sense). The fragmentation mass spectra, size/mass relations, correlation functions, range of scales over which fragmentation occurs, & time-dependent rates of fragmentation are predictable. We show how this depends on bulk turbulent properties (Mach numbers & power spectra). We also generalize to include rotation, complicated equations of state, collapsing/expanding backgrounds, magnetic fields, intermittency, & non-normal statistics. We derive how fragmentation is suppressed with 'stiffer' equations of state or different driving mechanisms. Suppression appears at an 'effective sonic scale' where Mach(R,rho)~1. Gas becomes stable below this scale for polytropic gamma>4/3, but fragmentation still occurs on larger scales. The scale-free nature of turbulence and gravity generically drives mass spectra and correlation functions towards universal shapes, with weak dependence on many properties of the media. Correlated fluctuation structures, non-Gaussian density distributions, & intermittency have surprisingly small effects on the fragmentation process. This is because fragmentation cascades on small scales are 'frozen in' when large-scale modes push the 'parent' region above the collapse threshold; though they collapse, their statistics are only weakly modified by the collapse process. With thermal support, structure develops 'top-down' in time via fragmentation cascades; but strong rotational support reverses this to 'bottom-up' growth via mergers & introduces a maximal instability scale distinct from the Toomre scale.
description: 28 pages, 12 figures (+appendices); MNRAS accepted (revised to match published version)
A framework for the evaluation of turbulence closures used in mesoscale ocean large-eddy simulations
Creators: name: Graham, Jonathan Pietarila
name: Ringler, Todd
Publisher: name: arXiv
Year: 2012
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Chaotic Dynamics (nlin.CD)
subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: We present a methodology to determine the best turbulence closure for an eddy-permitting ocean model through measurement of the error-landscape of the closure's subgrid spectral transfers and flux. We apply this method to 6 different closures for forced-dissipative simulations of the barotropic vorticity equation on a f-plane (2D Navier-Stokes equation). Using a high-resolution benchmark, we compare each closure's model of energy and enstrophy transfer to the actual transfer observed in the benchmark run. The error-landscape norms enable us to both make objective comparisons between the closures and to optimize each closure's free parameter for a fair comparison. The hyper-viscous closure most closely reproduces the enstrophy cascade, especially at larger scales due to the concentration of its dissipative effects to the very smallest scales. The viscous and Leith closures perform nearly as well, especially at smaller scales where all three models were dissipative. The Smagorinsky closure dissipates enstrophy at the wrong scales. The anticipated potential vorticity closure was the only model to reproduce the upscale transfer of kinetic energy from the unresolved scales, but would require high-order Laplacian corrections in order to concentrate dissipation at the smallest scales. The Lagrangian-averaged alpha-model closure did not perform successfully for forced 2D isotropic Navier-Stokes: small-scale filamentation is only slightly reduced by the model while small-scale roll-up is prevented. Together, this reduces the effects of diffusion.
description: 44 pages, 21 figures, 1 Appendix, submitted to Ocean Modeling
Newtonian limit of fully nonlinear cosmological perturbations in Einstein's gravity
Creators: name: Hwang, Jai-chan
name: Noh, Hyerim
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We prove that in the infinite speed-of-light limit (i.e., non-relativistic and subhorizon limits), the relativistic fully nonlinear cosmological perturbation equations in two gauge conditions, the zero-shear gauge and the uniform-expansion gauge, exactly reproduce the Newtonian hydrodynamic perturbation equations in the cosmological background; as a consequence, in the same two gauge conditions, the Newtonian hydrodynamic equations are exactly recovered in the Minkowsky background.
description: 12 Pages, appeared in JCAP
Vertical density waves in the Milky Way disc induced by the Sagittarius Dwarf Galaxy
Creators: name: Gómez, Facundo A.
name: Minchev, Ivan
name: O'Shea, Brian W.
name: Beers, Timothy C.
name: Bullock, James S.
name: Purcell, Chris W.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Recently, Widrow and collaborators announced the discovery of vertical density waves in the Milky Way disk. Here we investigate a scenario where these waves were induced by the Sagittarius dwarf galaxy as it plunged through the Galaxy. Using numerical simulations, we find that the Sagittarius impact produces North-South asymmetries and vertical wave-like behavior that qualitatively agrees with what is observed. The extent to which vertical modes can radially penetrate into the disc, as well as their amplitudes, depend on the mass of the perturbing satellite. We show that the mean height of the disc is expected to vary more rapidly in the radial than in the azimuthal direction. If the observed vertical density asymmetry is indeed caused by vertical oscillations, we predict radial and azimuthal variations of the mean vertical velocity, correlating with the spatial structure. These variations can have amplitudes as large as 8 km/s.
description: 6 pages, 6 figures, MNRAS accepted. Revised to reflect final version
Cosmic microwave background constraints on light dark matter candidates
Creators: name: Evoli, Carmelo
name: Pandolfi, Stefania
name: Ferrara, Andrea
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Unveiling the nature of cosmic dark matter (DM) is an urgent issue in cosmology. Here we make use of a strategy based on the search for the imprints left on the cosmic microwave background temperature and polarization spectra by the energy deposition due to annihilations of the most promising dark matter candidate, a stable WIMP of mass 1-20 GeV. A major improvement with respect to previous similar studies is a detailed treatment of the annihilation cascade and its energy deposition in the cosmic gas. This is vital as this quantity is degenerate with the annihilation cross-section . The strongest constraints are obtained from Monte Carlo Markov chain analysis of the combined WMAP7 and SPT datasets up to lmax = 3100. If annihilation occurs via the e+e- channel, a light WIMP can be excluded at the 2 σ c.l. as a viable DM candidate in the above mass range. However, if annihilation occurs via μ+μ- or τ+τ- channels instead we find that WIMPs with mass > 5 GeV might represent a viable cosmological DM candidate. We compare the results obtained in the present work with those obtained adopting an analytical simplified model for the energy deposition process widely used in literature, and we found that realistic energy deposition descriptions can influence the resulting constrains up to 60%.
description: 10 pages, 8 figures, 5 tables. Accepted for publication in MNRAS
Role of the spectral shape of quantum correlations in two-photon virtual-state spectroscopy
Creators: name: León-Montiel, R. de J.
name: Svozilík, J.
name: Salazar-Serrano, L. J.
name: Torres, J. P.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: It is controversial what is the true role of entanglement in two-photon virtual-state spectroscopy [Saleh et al, Phys. Rev. Lett. 80, 3483, 1998], a two-photon absorption spectroscopic technique that can retrieve information about the energy level structure of an atom or a molecule. The consideration of closely related techniques, such as multidimensional pump-probe spectroscopy [Roslyak et al, Phys. Rev. A 79, 063409, 2009], might suggest that spectroscopic information retrieved in the two-photon absorption process is the same regardless of the classical or quantum nature of the light source. Here, we solve this debate by making use of a full quantum formalism to show that the ability to obtain information about the energy level structure of a medium requires the existence of temporal (frequency) correlations between the absorbed photons. Moreover, we show that these correlations are not the only requisite for retrieving such information. In fact, it is a combination of both, the presence of frequency correlations and its specific spectral shape, which makes the realization of two-photon virtual-state spectroscopy possible. This result helps clarifying the discussion whether entanglement is needed or not, and also, to specify the type of two-photon source that needs to be used in order to experimentally perform the two-photon virtual-state spectroscopy technique.
Dispersive fields in de Sitter space and event horizon thermodynamics
Creators: name: Busch, Xavier
name: Parentani, Renaud
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: When Lorentz invariance is violated at high energy, the laws of black hole thermodynamics are apparently no longer satisfied. To shed light on this observation, we study dispersive fields in de Sitter space. We show that the Bunch-Davies vacuum state restricted to the static patch is no longer thermal, and that the Tolman law is violated. However we also show that, for free fields at least, this vacuum is the only stationary stable state, as if it were in equilibrium. We then present a precise correspondence between dispersive effects found in de Sitter and in black hole metrics. This indicates that the consequences of dispersion on thermodynamical laws could also be similar.
description: 19 pages. Black and White version on Phys.Rev.D server
Temporal percolation of a susceptible adaptive network
Creators: name: Valdez, L. D.
name: Macri, P. A.
name: Braunstein, L. A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Social and Information Networks (cs.SI)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: In the last decades, many authors have used the susceptible-infected-recovered model to study the impact of the disease spreading on the evolution of the infected individuals. However, few authors focused on the temporal unfolding of the susceptible individuals. In this paper, we study the dynamic of the susceptible-infected-recovered model in an adaptive network that mimics the transitory deactivation of permanent social contacts, such as friendship and work-ship ties. Using an edge-based compartmental model and percolation theory, we obtain the evolution equations for the fraction susceptible individuals in the susceptible biggest component. In particular, we focus on how the individual's behavior impacts on the dilution of the susceptible network. We show that, as a consequence, the spreading of the disease slows down, protecting the biggest susceptible cluster by increasing the critical time at which the giant susceptible component is destroyed. Our theoretical results are fully supported by extensive simulations.
A generating mechanism for higher order rogue waves
Creators: name: He, J. S.
name: Zhang, H. R.
name: Wang, L. H.
name: Porsezian, K.
name: Fokas, A. S.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We introduce a mechanism for generating higher order rogue waves (HRWs) of the nonlinear Schrödinger(NLS) equation: the progressive fusion and fission of $n$ degenerate breathers associated with a critical eigenvalue $λ_0$, creates an order $n$ HRW. By adjusting the relative phase of the breathers at the interacting area, it is possible to obtain different types of HRWs. The value $λ_0$ is a zero point of the eigenfunction of the Lax pair of the NLS equation and it corresponds to the limit of the period of the breather tending to infinity. By employing this mechanism we prove two conjectures regarding the total number of peaks, as well as a decomposition rule in the circular pattern of an order $n$ HRW.
description: 12 pages, 13 figures, To appear in Phys.Rev.E
Seesaw parametrization for n right-handed neutrinos
Creators: name: Heeck, Julian
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Introducing n right-handed neutrinos to the Standard Model yields, in general, massive active neutrinos. We give explicit parametrizations for the involved mixing and coupling matrices in terms of physical parameters for both the top-down and the bottom-up approach for arbitrary n. Bounds on the complex mixing angles in the bottom-up approach from perturbativity of the Yukawa couplings to charged lepton flavor violation are discussed. As a novel illustration of possible effects from n != 3, we extend the neutrino anarchy framework to arbitrary n; we show that while the anarchic mixing angles are insensitive to the number of singlets, the observed ratios of neutrino masses prefer small n for the simplest linear measure.
description: 12 pages, 4 figures. Added references and details about the sampling algorithm
Scaling properties of energy spreading in nonlinear Hamiltonian two-dimensional lattices
Creators: name: Mulansky, Mario
name: Pikovsky, Arkady
Publisher: name: arXiv
Year: 2012
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: In nonlinear disordered Hamiltonian lattices, where there are no propagating phonons, the spreading of energy is of subdiffusive nature. Recently, the universality class of the subdiffusive spreading according to the nonlinear diffusion equation (NDE) has been suggested and checked for one-dimensional lattices. Here, we apply this approach to two-dimensional strongly nonlinear lattices and find a nice agreement of the scaling predicted from the NDE with the spreading results from extensive numerical studies. Moreover, we show that the scaling works also for regular lattices with strongly nonlinear coupling, for which the scaling exponent is estimated analytically. This shows that the process of chaotic diffusion in such lattices does not require disorder.
description: 7 pages, 7 figures
title: What Drives Remittances During a Global Shock?
title: Evidence from the COVID-19 Pandemic in Mexico
titleType: Subtitle
Creators: name: Ambrosius, Christian
name: Campos-Vázquez, Raymundo M.
name: Esquivel, Gerardo
Publisher: name: Freie Universität Berlin
Year: 2021
Subjects: subject: Migration
subject: COVID-19
subject: Remittances
subject: Consumption
subject: Mexico
subject: 300 Sozialwissenschaften::330 Wirtschaft::337 Weltwirtschaft

description: During a global shock two forces act upon international remittances in opposite directions: income losses among migrants may reduce their ability to send remittances and, at the same time, migrants’ concern for their family’s wellbeing may prompt them to send more remittances back home. Which of these drivers prevail is an empirical matter. We assemble quarterly data at the subnational level in Mexico to study the behavior of remittances during the Covid-19 pandemic. We estimate elasticities of remittances with respect to employment conditions at both origin and destination places of Mexican migrants. Our results show that destination country conditions have been the main driver of remittances to Mexico, whereas origin country conditions had no discernible effect on remittances during the pandemic. We also show that contractions in consumption in Mexico are associated with reductions in remittances. We conclude that risk-coping via remittances provides limited protection during global crises.
5D non-symmetric gravity and geodesic confinement
Creators: name: Ghosh, Suman
name: Shankaranarayanan, S.
Publisher: name: arXiv
Year: 2012
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: This work focuses on an unexplored aspect of non-symmetric geometry where {\it only} the off-diagonal metric components along the extra dimension, in a 5-dimensional spacetime, are non-symmetric. We show that the energy densities of the stationary non-symmetric models are similar to that of brane models thereby mimicking the thick-brane scenario. We find that the massive test particles are confined near the location of the brane for both growing and decaying warp factors. This feature is unique to the non-symmetric nature of our model. We have also studied the dynamical models where standard 4D FLRW brane is embedded. Our analysis shows that the non-symmetric terms deconfine energy density at the early universe while automatically confine at late times.
description: 18 pages, 10 figures, updated version accepted for publication in GERG
EUROSCAL – Paving the Road Towards Automated Cybersecurity Certification in Europe
Creators: name: Luna García, Jesus
Publisher: name: Zenodo
Year: 2023

description: Despite the evident advantages automation could bring to traditional cloud cybersecurity certification processes, and in particular to underlying conformance assessments, there are still challenges associated to interoperability and standardization between all involved stakeholders. We refer not only to underlying implementations of relevant tools like the so-called Cloud Security Posture Management (CSPM), but also to the standardized representation of Infrastructure-as-Code cloud services (IaC), catalogues of security requirements, and the security configuration of cloud services to assess. These are necessary challenges to address before the notion of continuous (automated) monitoring of compliance can be fully realized e.g., in the new European Cybersecurity Certification Scheme for Cloud Service (EUCS). In this context, the present whitepaper introduces EUROSCAL, a MEDINA-driven initiative to promote the European use of NIST OSCAL (Open Security Controls Assessment Language) as a feasible solution for achieving interoperability and automating cloud security certification processes.
Winding branes and persistent currents
Creators: name: Khlebnikov, Sergei
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: A D5 brane winding around a stack of D3 branes can be used as a model of persistent current in a thin superconducting ring, with the number N of D3s corresponding to the number of transverse channels in the ring. We consider, in the large N limit, existence and properties of a gapped superconducting state with a uniform winding number density q. We find that there is a gapped classical solution for any q, no matter how large, but when q is larger than a certain q_m the state is unstable with respect to decay by phase slips. We argue that this decay produces strings via a version of the Hanany-Witten effect (in a non-transverse, non-supersymmetric arrangement of branes). This parallels the requirement of quasiparticle production in a clean (disorder-free) wire in field theory of superconductivity.
description: 19 pages, 3 figures; published in JHEP
Experimental study of temperature fluctuations in forced stably stratified turbulent flows
Creators: name: Eidelman, A.
name: Elperin, T.
name: Gluzman, I.
name: Kleeorin, N.
name: Rogachevskii, I.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We study experimentally temperature fluctuations in stably stratified forced turbulence in air flow. In the experiments with an imposed vertical temperature gradient, the turbulence is produced by two oscillating grids located nearby the side walls of the chamber. Particle Image Velocimetry is used to determine the turbulent and mean velocity fields, and a specially designed temperature probe with sensitive thermocouples is employed to measure the temperature field. We found that the ratio $\big[(\ell_x \nabla_x \bar{T})^2 + (\ell_y \nabla_y \bar{T})^2 + (\ell_z \nabla_z \bar{T})^2\big] / $ is nearly constant, is independent of the frequency of the grid oscillations and has the same magnitude for both, stably and unstably stratified turbulent flows, where $\ell_i$ are the integral scales of turbulence along $x, y, z$ directions, $\bar{T}$ and $θ$ are the mean and turbulent fluctuations components of the fluid temperature. We demonstrated that for large frequencies of the grid oscillations, the temperature field can be considered as a passive scalar, while for smaller frequencies the temperature field behaves as an active field. The theoretical predictions based on the budget equations for turbulent kinetic energy, turbulent potential energy ($\propto )$ and turbulent heat flux, are in a good agreement with the experimental results. Detailed comparison with experimental results obtained previously in unstably stratified forced turbulence is performed.
description: 12 pages, 18 figures, REVTEX4-1, revised version. arXiv admin note: substantial text overlap with arXiv:0912.2588
Strongly Interacting Matter at Finite Chemical Potential : Hybrid Model Approach
Creators: name: Srivastava, P. K.
name: Singh, C. P.
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Search for a proper and realistic equation of state (EOS) for strongly interacting matter used in the study of the QCD phase diagram still appears as a challenging problem. Recently, we constructed a hybrid model description for the quark gluon plasma (QGP) as well as hadron gas (HG) phases where we used an excluded volume model for HG and a thermodynamically consistent quasiparticle model for the QGP phase. The hybrid model suitably describes the recent lattice results of various thermodynamical as well as transport properties of the QCD matter at zero baryon chemical potential ($μ_{B}$). In this paper, we extend our investigations further in obtaining the properties of QCD matter at finite value of $μ_{B}$ and compare our results with the most recent results of lattice QCD calculation.
description: 14 pages, 9 figures
ReggaetóN, Dancehall, Mode-Up. Ser (MúSicos) Sanandresanos En La Era Digital
Creators: name: Ranocchiari, Dario
Publisher: name: Zenodo
Year: 2014
Subjects: ethnicity, reggaetón, dancehall, Caribbean, Colombia, San Andrés Island

description: During my ethnographic fieldwork about music and ethnicity on the island of San Andrés (Colombia), I had to deal repeatedly with the role of internet in the production, fruition and social meaning attribution of the music made by young Sanandreans. This role, which I had considered important but not determinant, is determining not only a radical change in the local music market, but also a new form of local identity. This identity, which is strictly related with the idea of insularity (―to be a Sanandrean‖), is influencing ethnic negotiation processes on the island in unexpected ways.