cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Surface plasmon oscillations in a semi-bounded semiconductor plasma
Creators: name: Shamansouri, M.
name: Misra, A. P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: We study the dispersion properties of surface plasmon oscillations in a semi-bounded semiconductor plasma with the effects of the Coulomb exchange force associated with the spin polarization of electrons and holes as well as the effects of the Fermi degenerate pressure and the quantum Bohm potential. Starting from a quantum hydrodynamic (QHD) model coupled to the Poisson equation, we derive the general dispersion relation for surface plasma waves. Previous results in this context are recovered. The dispersion properties of the surface waves are analyzed in some particular cases of interest and the relative influence of the quantum forces on these waves are also studied for a nano-sized GaAs semiconductor plasma. It is found that the Coulomb exchange effects significantly modify the behaviors of the surface plasmon waves. The present results are applicable to understand the propagation characteristics of surface waves in solid density plasmas.
description: 16 pages, 4 figures; To appear in Plasma Science and Technology (2017)
Product Customization and Customer Service Cost: An Empirical Analysis
Creators: name: Anuj  Kumar
Publisher: name: Carnegie Mellon University
Year: 2008
Subjects: subject: Information Systems
subject: FOS: Computer and information sciences
subject: 160510 Public Policy
subject: FOS: Political science

description: We conduct a field study on a prominent US health insurance firm to examine how customizing a product affects firm’s cost to serve the customers through its call center. In our setting, the product is a complex health insurance policy. Firm incurs substantial cost in serving the customers through its call center, and adjudicating the claims using its information systems. Firm sells either standard products, or in some instances allows customer groups to customize their policy by including, modifying certain aspects of the policy. We show that the process of customization is such that it increases users’ familiarity with his/her coverage and improves the fit with his/her medical needs. This, in turn, reduces their incentives to call the firm’s call center for clarifications regarding their product coverage. In particular, we show that users with customized policies call 30% less frequently than users with standard plan even after controlling for their number of doctor /facility visits. We also show that there is no difference in claim adjudication cost between a standard vs. customized policy. Overall, our results suggest that, customized products may be operationally cheaper to serve than standard products. Thus our paper provides a link between product features and the ex-post cost of serving them.
On the approximation of the limit cycles function
Creators: name: Cherkas, Leonid
name: Grin, Alexander
name: Schneider, Klaus R.
Publisher: name: Weierstrass Institute
Year: 2007
Subjects: subject: Family of limit cycles
subject: multiple limit cycle
subject: Liénard system
subject: 34C05
subject: 34C07
subject: 65L99

description: We consider planar vector fields depending on a real parameter. It is assumed that this vector field has a family of limit cycles which can be described by means of the limit cycles function $l$. We prove a relationship between the multiplicity of a limit cycle of this family and the order of a zero of the limit cycles function. Moreover, we present a procedure to approximate $l(x)$, which is based on the Newton scheme applied to the Poincaré function and represents a continuation method. Finally, we demonstrate the effectiveness of the proposed procedure by means of a Liénard system. The obtained result supports a conjecture by Lins, de Melo and Pugh.
Beyond Boltzmann-Gibbs statistics: Maximum entropy hyperensembles out-of-equilibrium
Creators: name: Crooks, Gavin E.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: What is the best description that we can construct of a thermodynamic system that is not in equilibrium, given only one, or a few, extra parameters over and above those needed for a description of the same system at equilibrium? Here, we argue the most appropriate additional parameter is the non-equilibrium entropy of the system, and that we should not attempt to estimate the probability distribution of the system, but rather the metaprobability (or hyperensemble) that the system is described by a particular probability distribution. The result is an entropic distribution with two parameters, one a non-equilibrium temperature, and the other a measure of distance from equilibrium. This dispersion parameter smoothly interpolates between certainty of a canonical distribution at equilibrium and great uncertainty as to the probability distribution as we move away from equilibrium. We deduce that, in general, large, rare fluctuations become far more common as we move away from equilibrium.
description: 4 pages
Asymptotic convergence results for a system of partial differential equations with hysteresis
Creators: name: Eleuteri, Michela
name: Krejčí, Pavel
Publisher: name: Weierstrass Institute
Year: 2007
Subjects: subject: partial differential equations
subject: hysteresis
subject: asymptotic convergence
subject: Preisach operator
subject: 35K55
subject: 47J40
subject: 35B40

description: A partial differential equation motivated by electromagnetic field equations in ferromagnetic media is considered with a relaxed rate dependent constitutive relation. It is shown that the solutions converge to the unique solution of the limit parabolic problem with a rate independent Preisach hysteresis constitutive operator as the relaxation parameter tends to zero.
title: Existenzielle Bedrohung und Entwürdigung. Armut, Gewalt und Wohnungslosigkeit im Alltag marginalisierter Frauen
Creators: name: Wimmer, Christopher
Publisher: name: Humboldt-Universität zu Berlin
Year: 2022
Subjects: subject: Armut
subject: Gewalt gegen Frauen
subject: Marginalisierung
subject: Wohnungslosigkeit
subject: ddc:300

description: Der Beitrag beschäftigt sich mit spezifischen Armutslagen von Frauen, wobei der Marginalisierungsbegriff in den Mittelpunkt gerückt wird. Die drei Phänomene Armut, Gewalterfahrungen und Wohnungslosigkeit werden als zentrale Aspekte des Alltags von marginalisierten Frauen bestimmt und dargestellt. Insgesamt sind in der sozialen Ungleichheitsforschung Studien zu gesellschaftlicher Marginalisierung schon rar, empirische Untersuchungen (quantitativ wie qualitativ) zur Marginalisierung von Frauen sind noch seltener. Anhand von neun Interviews mit armen und marginalisierten Frauen, die mit der dokumentarischen Methode ausgewertet wurden, verdeutlicht der Beitrag, wie die Befragten ihren Alltag gestalten und wie sie mit ihrer Armut und Marginalisierung umgehen. Somit wird eine Perspektive verfolgt, die von den Frauen selbst ausgeht und zeigt, wie sie diese Phänomene konkret erfahren und mit ihnen umgehen. Zentral dabei ist der Kampf der befragten Frauen um gesellschaftliche Respektabilität.
X-Shooter observations of low-mass stars in the Eta Chamaeleontis association
Creators: name: Rugel, Michael
name: Fedele, Davide
name: Herczeg, Gregory
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The nearby Eta Chamaeleontis association is a collection of 4-10 Myr old stars with a disk fraction of 35-45%. In this study, the broad wavelength coverage of VLT/X-Shooter is used to measure the stellar and mass accretion properties of 15 low mass stars in the Eta Chamaeleontis association. For each star, the observed spectrum is fitted with a non-accreting stellar template and an accretion spectrum obtained from assuming a plane-parallel hydrogen slab. Five of the eight stars with an IR disk excess show excess UV emission, indicating ongoing accretion. The accretion rates measured here are similar to those obtained from previous measurements of excess UV emission, but tend to be higher than past measurements from H-alpha modeling. The mass accretion rates are consistent with those of other young star forming regions.
description: Accepted for publication in Astronomy & Astrophysics
On the Landau--Levich problem for non-Newtonian liquids
Creators: name: Afanasiev, Konstantin
name: Münch, Andreas
name: Wagner, Barbara
Publisher: name: Weierstrass Institute
Year: 2007
Subjects: subject: Lubrication models
subject: non-Newtonian flow
subject: fluid dynamics
subject: phase plane analysis
subject: 34B15
subject: 35G25
subject: 35K55
subject: 35Q35
subject: 68.15.+e

description: In this paper the drag-out problem for shear-thinning liquids at variable inclination angle is considered. For this free boundary problem dimension-reduced lubrication equations are derived for the most commonly used viscosity models, namely, the power-law, Ellis and Carreau model. For the resulting lubrication models a system of ordinary differential equation governing the steady state solutions is obtained. Phase plane analysis is used to characterize the type of possible steady state solutions and their dependence on the rheological parameters.
Growth of Antiperovskite Oxide Ca3SnO Films by Pulsed Laser Deposition
Creators: name: Minohara, Makoto
name: Yukawa, Ryu
name: Kitamura, Miho
name: Kumai, Reiji
name: Murakami, Youichi
name: Kumigashira, Hiroshi
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report the epitaxial growth of Ca3SnO antiperovskite oxide films on (001)-oriented cubic yttria-stabilized zirconia (YSZ) substrates by using a conventional pulsed laser deposition (PLD) technique. In this work, a sintered Ca3SnO pellet is used as the ablation target. X-ray diffraction measurements demonstrate the (001) growth of Ca3SnO films with the antiperovskite structure and a cube-on-cube orientation relationship to the YSZ substrate. The successful synthesis of the antiperovskite phase is further confirmed by x-ray photoemission spectroscopy. These results strongly suggest that antiperovskite-oxide films can be directly grown on substrates from the target material using a PLD technique.
Privacy Concerns and Information Disclosure: An Illusion of Control Hypothesis
Creators: name: Brandimarte, Laura
Publisher: name: Carnegie Mellon University
Year: 2009
Subjects: subject: Information Systems
subject: FOS: Computer and information sciences
subject: 160510 Public Policy
subject: FOS: Political science

description: This paper investigates one possible explanation for people’s conflicting attitudes regarding protection of private information. The proliferation of studies about crimes such as identity theft and cyber-stalking, together with the sharp increase in the number of victims, and the easiness with which data can be retrieved on the Web has raised people’s awareness and concerns about the consequences of revelation of private information, especially on the Internet. On the other hand, the increasing popularity of online social networks and blogs suggests that more and more people are willing to reveal all kinds of information about themselves to the members of these communities. In order to understand this dichotomy, we introduce and test the hypothesis that people may confuse control over publication of private information with control over accessibility and use of that information by third parties. Borrowing the terminology of psychology and behavioral decision research, we refer to this hypothesis as “illusion of control”. We designed two experiments in the form of online surveys to students at Carnegie Mellon University, in which we manipulated control over information publication. The results provide empirical evidence of illusion of control.
Rejection of the hypothesis that Markarian 501 TeV photons are pure Bose-Einstein condensates
Creators: name: The HEGRA Collaboration
name: Aharonian, F.
name: Akhperjanian, A.
name: Barrio, J.
Publisher: name: arXiv
Year: 2000
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The energy spectrum of the Blazar type galaxy Markarian 501 (Mrk 501) as measured by the High-Energy-Gamma-Ray Astronomy (HEGRA) air Cerenkov telescopes extends beyond 16 TeV and constitutes the most energetic photons observed from an extragalactic object. A fraction of the emitted spectrum is possibly absorbed in interactions with low energy photons of the diffuse extragalactic infrared radiation, which in turn offers the unique possibility to measure the diffuse infrared radiation density by TeV spectroscopy. The upper limit on the density of the extragalactic infrared radiation derived from the TeV observations imposes constraints on models of galaxy formation and stellar evolution. One of the recently published ideas to overcome severe absorption of TeV photons is based upon the assumption that sources like Mrk 501 could produce Bose-Einstein condensates of coherent photons. The condensates would have a higher survival probability during the transport in the diffuse radiation field and could mimic TeV air shower events. The powerful stereoscopic technique of the HEGRA air Cerenkov telescopes allows to test this hypothesis by reconstructing the penetration depths of TeV air shower events: Air showers initiated by Bose-Einstein condensates are expected to reach the maximum of the shower development in the atmosphere earlier than single photon events. By comparing the energy-dependent penetration depths of TeV photons from Mrk 501 with those from the TeV standard-candle Crab Nebula and simulated air shower events, we can reject the hypothesis that TeV photons from Mrk 501 are pure Bose-Einstein condensates.
description: 9 pages, 2 figures, published by ApJ Letters, revised version (simulation results added)
Stochastic gravitational wave background from smoothed cosmic string loops
Creators: name: Blanco-Pillado, Jose J.
name: Olum, Ken D.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We do a complete calculation of the stochastic gravitational wave background to be expected from cosmic strings. We start from a population of string loops taken from simulations, smooth these by Lorentzian convolution as a model of gravitational back reaction, calculate the average spectrum of gravitational waves emitted by the string population at any given time, and propagate it through a standard model cosmology to find the stochastic background today. We take into account all known effects, including changes in the number of cosmological relativistic degrees of freedom at early times and the possibility that some energy is in rare bursts that we might never have observed.
description: 28 pages
Ostwald ripening of faceted two-dimensional islands
Creators: name: Kaganer, Vladimir
name: Braun, Wolfgang
name: Sabelfeld, Karl
Publisher: name: Weierstrass Institute
Year: 2007
Subjects: subject: Ostwald ripening
subject: Lifshitz--Slyozov--Wagner theory
subject: Becker--Döring equations
subject: faceted crystalline droplets
subject: Gibbs--Thomson formula
subject: kinetic Monte Carlo simulations
subject: 65C05
subject: 65C20
subject: 81.10.Aj
subject: 05.10.Ln
subject: 68.43.Jk
subject: 81.15.-z

description: We study Ostwald ripening of two-dimensional adatom and advacancy islands on a crystal surface by means of kinetic Monte Carlo simulations. At large bond energies the islands are square-shaped, which qualitatively changes the coarsening kinetics. The Gibbs--Thomson chemical potential is violated: the coarsening proceeds through a sequence of `magic' sizes corresponding to square or rectangular islands. The coarsening becomes attachment-limited, but Wagner's asymptotic law is reached only after a very long transient time. The unusual coarsening kinetics obtained in the Monte Carlo simulations are well described by the Becker--Döring equations of nucleation kinetics. These equations can be applied to a wide range of coarsening problems.
Apoptosis signaling is activated as a transient pulse in neurons
Creators: name: Deshmukh, Mohanish
name: Hammond, Elizabeth S.
name: Spiess, Keeley L.
name: Romero, Selena E.
name: Patterson, Rachel L.
name: Hollville, Emilie
name: Geden, Matthew J.
name: Girardi, Quintin B.
Publisher: name: Springer Nature
Year: 2024

description: Apoptosis is a fundamental process of all mammalian cells but exactly how it is regulated in different primary cells remains less explored. In most contexts, apoptosis is engaged to eliminate cells. However, postmitotic cells such as neurons must efficiently balance the need for developmental apoptosis versus the physiological needs for their long-term survival. Neurons are capable of reversing the commitment to death even after the point of cytochrome c release. This ability of neurons to recover from an apoptotic signal suggests that activation of the apoptotic pathway in neurons could be much more transient than is currently recognized. Here, we investigated whether the apoptotic pathway in neurons is a persistent signal or a transient pulse in continuous presence of apoptotic stimulus. We have examined this at three key steps in apoptotic signaling: phosphorylation of c-Jun, induction of the BH3-only family proteins and Bax activation. Strikingly, we found all three of these events occur as transient signals following Nerve Growth Factor (NGF) deprivation-induced apoptosis in sympathetic neurons. This transient apoptosis signal would effectively allow neurons to reset and permit recovery if the apoptotic stimulus is reversed. Excitingly, we have also discovered that a neuron’s ability to recover from an apoptotic signal is dependent on expression of the anti-apoptotic Bcl-2 family protein Bcl-xL. Bcl-xL-deficient neurons lose the ability to recover from NGF deprivation even if NGF is restored. Additionally, we show that recovery from a previous exposure to NGF deprivation is protective against subsequent deprivation. Together, these results define a novel mechanism by which apoptosis is regulated in neurons where the transient pulse of the apoptotic signaling supports neuronal resilience.
On S-duality for Non-Simply-Laced Gauge Groups
Creators: name: Argyres, Philip C.
name: Kapustin, Anton
name: Seiberg, Nathan
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We point out that for N=4 gauge theories with exceptional gauge groups G_2 and F_4 the S-duality transformation acts on the moduli space by a nontrivial involution. We note that the duality groups of these theories are the Hecke groups with elliptic elements of order six and four, respectively. These groups extend certain subgroups of SL(2,Z) by elements with a non-trivial action on the moduli space. We show that under an embedding of these gauge theories into string theory, the Hecke duality groups are represented by T-duality transformations.
description: 8 pages, latex. v2: references added
Spin effects on the semiclassical trajectories of Dirac electrons
Creators: name: Gutierrez-Jauregui, R.
name: Perez-Pascual, R.
name: Jauregui, R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The relativistic semiclassical evolution of the position of an electron in the presence of an external electromagnetic field is studied in terms of a Newton equation that incorporates spin effects directly. This equation emerges from the Dirac equation and allows the identification of scenarios where spin effects are necessary to understand the main characteristics of the electron trajectories. It involves the eigenvalues of the non-Hermitian operator $Σ_{μν}F^{μν}$ with $Σ_{μν}$ and $F^{μν}$ as the spin and electromagnetic tensors. The formalism allows a deeper understanding on the physics behind known analytical solutions of the Dirac equation when translational dynamics decouples from spin evolution. As an illustrative example, it is applied to an electron immersed in an electromagnetic field which exhibits chiral symmetry and optical vortices. It is shown that the polarization of intense structured light beams can be used to suppress or enhance spin effects on the electron semiclassical trajectory; the latter case yields a realization of a Stern-Gerlach apparatus for an electron
description: 18 pages, 3 figures
Antimicrobial and resource utilization with T2 magnetic resonance for rapid diagnosis of bloodstream infections: systematic review with meta-analysis of controlled studies
Creators: name: Giannella, Maddalena
name: Pankey, George A.
name: Pascale, Renato
name: Miller, Valerie M.
name: Miller, Larry E.
name: Seitz, Tamara
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Space Science
subject: Medicine
subject: Sociology
subject: FOS: Sociology
subject: Biological Sciences not elsewhere classified

description: Objectives: To compare antimicrobial and resource utilization with T2 Magnetic Resonance (T2MR) versus blood culture (BC) in patients with suspected bloodstream infection. Methods: We systematically searched MEDLINE, EMBASE, and CENTRAL for randomized trials or observational controlled studies of patients with suspected bloodstream infection receiving a diagnosis with T2MR or BC. Using an inverse variance meta-analysis model, we reported mortality using the risk ratio (RR) and the remaining outcomes as the mean difference (MD). Results: Fourteen studies were included in the meta-analysis. Time to detection (MD = −81 hours; p < 0.001) and time to species identification (MD = −77 hours; p < 0.001) were faster with T2MR. Patients testing positive on T2MR received targeted antimicrobial therapy faster (−42 hours; p < 0.001) and patients testing negative on T2MR were de-escalated from empirical therapy faster (−7 hours; p = 0.02) vs. BC. Length of intensive care unit stay (MD = −5.0 days; p = 0.03) and hospital stay (MD = −4.8 days; p = 0.03) were shorter with T2MR. Mortality rates were comparable between T2MR and BC (28.9% vs. 29.9%, RR = 1.02, p = 0.86). Conclusion: Utilization of T2MR for identification of bloodstream pathogens provides faster time to detection, faster transition to targeted microbial therapy, faster de-escalation of empirical therapy, shorter ICU and hospital stay, and with comparable mortality rate versus BC.
Fission barriers and asymmetric ground states in the relativistic mean field theory
Creators: name: Rutz, K.
name: Maruhn, J. A.
name: Reinhard, P. -G.
name: Greiner, W.
Publisher: name: arXiv
Year: 1996
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The symmetric and asymmetric fission path for 240Pu, 232Th, and 226Ra is investigated within the relativistic mean field model. Standard parametrizations which are well fitted to nuclear ground state properties are found to deliver reasonable qualitative and quantitative features of fission, comparable to similar nonrelativstic calculations. Furthermore, stable octupole deformations in the ground states of Radium isotopes are investigated. They are found in a series of isotopes, qualitatively in agreement with nonrelativistic models. But the quantitative details differ amongst the models and between the various relativsitic parametrizations.
description: 30 pages RevTeX, 7 tables, 12 low resolution Gif figures (high resolution PostScript versions are available at http://www.th.physik.uni-frankfurt.de/~bender/nucl_struct_publications.html or at ftp://th.physik.uni-frankfurt.de/pub/bender )
Relativistic shock propagation in finite conductivity media
Creators: name: Loules, Argyrios
Publisher: name: Zenodo
Year: 2024

description: Gamma-ray bursts are the most energetic astrophysical phenomena, occurring when matter is violently expelled at near lightspeed velocities during a cataclysmic event. The interaction of this relativistic outflow of matter with the surrounding circumburst medium leads to the formation of relativistic shocks. We investigate the properties of relativistic shock propagation in a magnetized medium characterized by a finite electrical conductivity and define a dimensionless parameter, linearly related to the electrical conductivity, which determines the properties of the post-shock medium. Our results indicate that this parameter governs the degree to which the shock affects the medium’s electromagnetic field, and consequently, its hydrodynamical properties. For low values of this dimensionless parameter, the shock acts as a purely hydrodynamic one. As the value of this parameter increases, the propagation medium’s electromagnetic field is increasingly affected, with the behavior of the post-shock medium approaching the one predicted by the ideal MHD jump conditions. Finally, we apply this theory to examining the impact of the propagation medium's electrical conductivity on the dynamical conditions inside a relativistic blastwave and the propagation velocities of the forward and reverse shocks.
On the construction of bifurcation curves related to limit cycles of multiplicity three for planar vector fields
Creators: name: Cherkas, Leonid
name: Grin, Alexander
name: Schneider, Klaus R.
Publisher: name: Weierstrass Institute
Year: 2007
Subjects: subject: Multiple limit cycle
subject: degenerate Hopf bifurcation
subject: continuation method
subject: 34C05
subject: 34C23

description: For plane vector fields depending on three parameters we describe an algorithm to construct a curve in the parameter space such that to each point of this curve there belongs a vector field possessing a limit cycle of multiplicity three. One point of this curve is related to the bifurcation of a limit cycle of multiplicity three from an equilibrium point. The underlying procedure is a continuation method.
Magnetism of iron: from the bulk to the monoatomic wire
Creators: name: Autes, Gabriel
name: Barreteau, Cyrille
name: Spanjaard, Daniel
name: Desjonqueres, Marie-Catherine
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The magnetic properties of iron (spin and orbital magnetic moments, magnetocrystalline anisotropy energy) in various geometries and dimensionalities are investigated by using a parametrized tight-binding model in an $s$, $p$ and $d$ atomic orbital basis set including spin polarization and the effect of spin-orbit coupling. The validity of this model is well established by comparing the results with those obtained by using an ab-initio code. This model is applied to the study of iron in bulk bcc and fcc phases, $(110)$ and $(001)$ surfaces and to the monatomic wire, at several interatomic distances. New results are derived. The variation of the component of the orbital magnetic moment on the spin quantization axis has been studied as a function of depth, revealing a significant enhancement in the first two layers, especially for the $(001)$ surface. It is found that the magnetic anisotropy energy is drastically increased in the wire and can reach several meV. This is also true for the orbital moment, which in addition is highly anisotropic. Furthermore it is shown that when the spin quantization axis is neither parallel nor perpendicular to the wire the average orbital moment is not aligned with the spin quantization axis. At equilibrium distance the easy magnetization axis is along the wire but switches to the perpendicular direction under compression. The success of this model opens up the possibility of obtaining accurate results on other elements and systems with much more complex geometries.
Pricing Advice: The market for diagnostic information
Creators: name: Arora, Ashish
name: Fosfuri, Andrea
Publisher: name: Carnegie Mellon University
Year: 2003
Subjects: subject: Information Systems
subject: FOS: Computer and information sciences
subject: 160510 Public Policy
subject: FOS: Political science

description: Diagnostic information helps agents to make more accurate decisions. One such decision is about investing in projects with uncertain outcomes. The value of diagnostic information is the difference in expected payoffs with and without it, and we show that such a value is non-monotonic in the ex-ante expected value of the project to be undertaken. We analyze optimal pricing schemes for selling information to buyers with unknown ex ante value. With a monopolist information seller, a striking result is that the optimal menu of contracts is remarkably simple. A pure royalty is offered to buyers whose projects have low ex-ante expected value and a pure fixed fee is offered to buyers whose projects have high ex-ante expected value. This result is robust to the presence of different types of information and to the introduction of competition in the market for diagnostic information.
Price and Quality Dispersion in an Offshoring Market: Evidence from Semiconductor Production Services
Creators: name: Byrne, David
name: Kovak, Brian
name: Michaels, Ryan
Publisher: name: Carnegie Mellon University
Year: 2014
Subjects: subject: Information Systems
subject: FOS: Computer and information sciences
subject: 160510 Public Policy
subject: FOS: Political science

description: We study price and quality differences across international intermediate input suppliers. Our uniquely detailed transaction-level data exhibit large price differences across suppliers of observationally identical products, but these price gaps narrow over the product life cycle. We disentangle pure (frictional) price dispersion from unobserved quality differences using a framework in which switching suppliers is costly. We construct a quality-adjusted price index using these results and show that pure price dispersion biases standard indexes upward. Finally, we demonstrate how to bound the true constant-quality price index using commonly available data and without making strong market structure assumptions.
Anomalous Composition-Induced Crossover in the Magnetic Properties of the Itinerant-Electron Antiferromagnet Ca{1-x}Sr{x}Co{2-y}As{2}
Creators: name: Sangeetha, N. S.
name: Smetana, V.
name: Mudring, A. -V.
name: Johnston, D. C.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The inference of Ying et al. [EPL 104, 67005 (2013)] of a composition-induced change from c-axis ordered-moment alignment in a collinear A-type antiferromagnetic (AFM) structure (AFMI) at small x to ab-plane alignment in an unknown AFM structure (AFMII) at larger x in Ca(1-x)Sr(x)Co(2-y)As(2) with the body-centered tetragonal ThCr2Si2 structure is confirmed. Our major finding is an anomalous magnetic behavior in the crossover region 0.2 < x < 0.3 between these two phases. In this region the magnetic susceptibility versus temperature chi_ab(T) measured with magnetic fields H applied in the ab plane exhibit typical AFM behaviors with cusps at the Neel temperatures of about 65 K, whereas chi_c(T) and the low-temperature isothermal magnetization M_c(H) with H aligned along the c axis exhibit extremely soft ferromagnetic-like behaviors.
description: 6 pages and 5 figures, plus 26 pages and 26 figures of Supplemental Information
An Alternative To The Horizontality Condition In Superfield Approach To BRST Symmetries
Creators: name: Malik, R. P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We provide an alternative to the gauge covariant horizontality condition which is responsible for the derivation of the nilpotent (anti-)BRST symmetry transformations for the gauge and (anti-)ghost fields of a (3 + 1)-dimensional (4D) interacting 1-form non-Abelian gauge theory in the framework of the usual superfield approach to Becchi-Rouet-Stora-Tyutin (BRST) formalism. The above covariant horizontality condition is replaced by a gauge invariant restriction on the (4, 2)-dimensional supermanifold, parameterized by a set of four spacetime coordinates x^μ(μ= 0, 1, 2, 3) and a pair of Grassmannian variables θand \barθ. The latter condition enables us to derive the nilpotent (anti-)BRST symmetry transformations for all the fields of an interacting 4D 1-form non-Abelian gauge theory where there is an explicit coupling between the gauge field and the Dirac fields. The key differences and striking similarities between the above two conditions are pointed out clearly.
description: LaTeX file, 20 pages, journal version
Nonlinear diffusion equations as asymptotic limits of Cahn--Hilliard systems on unbounded domains via Cauchy's criterion
Creators: name: Fukao, Takeshi
name: Kurima, Shunsuke
name: Yokota, Tomomi
Publisher: name: arXiv
Year: 2017
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: This paper develops an abstract theory for subdifferential operators to give existence and uniqueness of solutions to the initial-boundary problem (P) for the nonlinear diffusion equation in an unbounded domain $Ω\subset\mathbb{R}^N$ ($N\in{\mathbb N}$), written as \[ \frac{\partial u}{\partial t} + (-Δ+1)β(u) = g \quad \mbox{in}\ Ω\times(0, T), \] which represents the porous media, the fast diffusion equations, etc., where $β$ is a single-valued maximal monotone function on $\mathbb{R}$, and $T>0$. Existence and uniqueness for (P) were directly proved under a growth condition for $β$ even though the Stefan problem was excluded from examples of (P). This paper completely removes the growth condition for $β$ by confirming Cauchy's criterion for solutions of the following approximate problem (P)$_{\varepsilon}$ with approximate parameter $\varepsilon>0$: \[ \frac{\partial u_{\varepsilon}}{\partial t} + (-Δ+1)(\varepsilon(-Δ+1)u_{\varepsilon} + β(u_{\varepsilon}) + π_{\varepsilon}(u_{\varepsilon})) = g \quad \mbox{in}\ Ω\times(0, T), \] which is called the Cahn--Hilliard system, even if $Ω\subset \mathbb{R}^N$ ($N \in \mathbb{N}$) is an unbounded domain. Moreover, it can be seen that the Stefan problem is covered in the framework of this paper.
Price and Purity Analysis for Illicit Drug: Data and Conceptual Issues
Creators: name: Caulkins, Jonathan
Publisher: name: Carnegie Mellon University
Year: 2005
Subjects: subject: Information Systems
subject: FOS: Computer and information sciences
subject: 160510 Public Policy
subject: FOS: Political science

description: Data on illicit drug purity and prices are invaluable but problematic. Purists argue they are unsuitable for economic analysis (Manski et al., 2001; Horowitz, 2001), but in reality they are used frequently (ONDCP 2001a, 2001b, 2004; Grossman, 2004). This paper reviews data and conceptual issues that people producing, analyzing, and consuming drug price and purity series should understand in order to reduce the likelihood of misinterpretation. It also identifies aspects of drug markets that are both poorly understood and relevant to some of these issues. They constitute a useful research agenda for health and law enforcement communities who would benefit from better data on the supply, availability, and use of illicit drugs.
Existence of bounded discrete steady state solutions of the van Roosbroeck system on boundary conforming Delaunay grids
Creators: name: Gärtner, Klaus
Publisher: name: Weierstrass Institute
Year: 2007
Subjects: subject: Reaction-diffusion systems
subject: discrete bounded solutions
subject: Delaunay grids
subject: discrete weak maximum principle
subject: 65M12
subject: 35K65

description: The classic van Roosbroeck system describes the carrier transport in semiconductors in a drift diffusion approximation. Its analytic steady state solutions fulfill bounds for some mobility and recombination/generation models. The main goal of this paper is to establish the identical bounds for discrete in space, steady state solutions on 3d boundary conforming Delaunay grids and the classical Scharfetter-Gummel-scheme. Together with a uniqueness proof for small applied voltages and the known dissipativity (continuous as well as space and time discrete) these discretization techniques carry over the essential analytic properties to the discrete case. The proofs are of interest for deriving averaging schemes for space or state dependent material parameters, which are preserving these qualitative properties, too. To illustrate the properties of the scheme 1, 4, 16 elementary cells of a modified CoolMOS like structure are depleted by increasing the applied voltage until steady state avalanche breakdown occurs.
PERCEPÇÕES SOBRE O CONSUMO DE DROGAS (ZOMBO) ENTRE OS JOVENS NO BAIRRO DE CHIPANGARA CIDADE DA BEIRA/MOÇAMBIQUE: ESTUDO QUALITATIVO
Creators: name: Vasco, Pedro Artur
name: Camacho, Ancha Celeste Gabriel
name: Amalique, Dubalelane António
Publisher: name: Zenodo
Year: 2024

description: Resumo

Introdução: A droga não é um problema em si, ela é também o problema da construção social, de construção das comunicações que se fazem em torno dela. O uso de substâncias ilícitas está relacionado à própria visão de mundo de um grupo social e à construção de uma identidade individual e cultural. Objectivo: o estudo visa compreender as percepções dos moradores do bairro Chipangara sobre o consumo de drogas (Zombo) entre os jovens. Visto que o consumo desta droga tende a se alastrar ao nível da cidade da Beira e as autoridades ainda não têm a sua classificação apurada sobre sua origem, a sua designação cientifica e pouco ainda os moldes do seu consumo. Métodos: A pesquisa foi inteiramente do tipo qualitativa e com método de abordagem hipotético-dedutivo.  Foram feitas através de entrevistas semiestruturadas, onde foram abordadas 12 pessoas. Resultados: Os resultados apontam que a droga não é uma novidade para os nossos entrevistados, a droga tem diversas características podendo apresentar-se em formato de pó ou pedrinha e o seu consumo varia de consumidor para consumidor, pois alguns enrolam a droga junto ao cigarro e outros queimam em um recipiente com objetivo de inalar a fumaça. Conclusão: chegamos a conclusão de que, a droga (Zombo) é muito forte a ponto de criar dependência tal qual a heroína, onde muitos acreditam ser a própria heroína em outro formato, e também tem a fama de ser uma droga devastadora pois o consumidor acaba perdendo a visão do futuro, começando a cometer não só roubos como crimes tanto no seio familiar como fora dele.

 

Palavras-chave: Percepções sociais; Drogas; Zombo; Juventude
title: Kapitalistische Strukturlogiken in der neuen Mitleidsökonomie
Creators: name: Eberle, Hannah-Maria
Publisher: name: Humboldt-Universität zu Berlin
Year: 2022
Subjects: subject: Armut
subject: Ehrenamt
subject: Reproduktionsarbeit
subject: Wohlfahrtsstaat
subject: ddc:303

description: Der Begriff der neuen Mitleidsökonomie beschreibt ein System, in dem unbezahlt Tätige von Armut betroffene Menschen mit Lebensmitteln, Kleidung oder anderen existenziellen Gütern versorgen. Gemeint sind Tafeln, Sozialkaufhäuser oder Wärmestuben für Wohnungslose und in einem erweiterten Verständnis auch foodsharing-Initativen, Nachbarschaftsküchen oder onlinebasierte Secondhand-Angebote. Das unbezahlte Engagement der freiwillig Helfenden oder Aktivist*innen wird zumeist als Arbeit aus Liebe, Fürsorge oder Mitleid verhandelt und die Notwendigkeit der Arbeit somit unsichtbar gemacht. Anlehnend an die feministisch-marxistische Kritik der 1970er- und 1980er-Jahre weist der Artikel erstens auf den reproduktiven Charakter dieser Tätigkeiten und deren gesellschaftliche Notwendigkeit hin. Die Ausbeutungsdimension der teilweise nur vermeintlich Freiwilligen wird herausgearbeitet sowie das System insgesamt in die aktuelle Sozialpolitik eingeordnet. Zweitens nimmt der Artikel weitere kapitalistische Strukturlogiken in den Blick und verdeutlicht die mögliche Konsequenz, nämlich die Entstehung eines parallelen, zweiten Versorgungsmarkts für Armutsbetroffene.
Superconducting films with antidot arrays - novel behavior of the critical current
Creators: name: Berdiyorov, G. R.
name: Milošević, M. V.
name: Peeters, F. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Novel behavior of the critical current density $j_{c}$ of a regularly perforated superconducting film is found, as a function of applied magnetic field $H$. Previously pronounced peaks of $j_{c}$ at matching fields were always found to decrease with increasing $H$. Here we found a {\it reversal of this behavior} for particular geometrical parameters of the antidot lattice and/or temperature. This new phenomenon is due to a strong ``caging'' of interstitial vortices between the pinned ones. We show that this vortex-vortex interaction can be further tailored by an appropriate choice of the superconducting material, described by the Ginzburg-Landau parameter $κ$. In effective type-I samples we predict that the peaks in $j_{c}(H)$ at the matching fields are transformed into a {\it step-like behavior}.
description: 5 pages, 4 figures
Simulation of microwave circuits and laser structures including PML by means of FIT
Creators: name: Hebermehl, Georg
name: Schefter, Jürgen
name: Schlundt, Rainer
name: Tischler, Thorsten
name: Zscheile, Horst
name: Heinrich, Wolfgang
Publisher: name: Weierstrass Institute
Year: 2004
Subjects: subject: Microwave device
subject: Semiconductor laser
subject: Simulation
subject: Maxwell's equations
subject: Boundary value problem
subject: PML boundarycondition
subject: Eigenvalue problem
subject: Linearalgebraic equations
subject: Rectangular grids
subject: Tetrahedral nets
subject: 35Q60
subject: 65N22
subject: 65F15
subject: 65F10

description: Field-oriented methods which describe the physical properties of microwave circuits and optical structures are an indispensable tool to avoid costly and time-consuming redesign cycles. Commonly the electromagnetic characteristics of the structures are described by the scattering matrix which is extracted from the orthogonal decomposition of the electric field. The electric field is the solution of an eigenvalue and a boundary value problem for Maxwell's equations in the frequency domain. We discretize the equations with orthogonal grids using the Finite Integration Technique (FIT). Maxwellian grid equations are formulated for staggered nonequidistant rectangular grids and for tetrahedral nets with corresponding dual Voronoi cells. The interesting modes of smallest attenuation are found solving a sequence of eigenvalue problems of modified matrices. To reduce the execution time for high-dimensional problems a coarse and a fine grid is used. The calculations are carried out, using two levels of parallelization. The discretized boundary value problem, a large-scale system of linear algebraic equations with different right-hand sides, is solved by a block Krylov subspace method with various preconditioning techniques. Special attention is paid to the Perfectly Matched Layer boundary condition (PML) which causes non physical modes and a significantly increased number of iterations in the iterative methods.
High Impedance Detector Arrays for Magnetic Resonance
Creators: name: Zhang, Bei
name: Sodickson, Daniel K.
name: Cloos, Martijn A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: Resonant inductive coupling is commonly seen as an undesired fundamental phenomenon emergent in densely packed resonant structures, such as nuclear magnetic resonance phased array detectors. The need to mitigate coupling imposes rigid constraints on the detector design, impeding performance and limiting the scope of magnetic resonance experiments. Here we introduce a high impedance detector design, which can cloak itself from electrodynamic interactions with neighboring elements. We verify experimentally that the high impedance detectors do not suffer from signal-to-noise degradation mechanisms observed with traditional low impedance elements. Using this new-found robustness, we demonstrate an adaptive wearable detector array for magnetic resonance imaging of the hand. The unique properties of the detector glove reveal new pathways to study the biomechanics of soft tissues, and exemplify the enabling potential of high-impedance detectors for a wide range of demanding applications that are not well suited to traditional coil designs.
description: 16 pages, 12 figures, videos available upon request
On the Fading Number of a Graph
Creators: name: Kok, Johan
name: Naduvath, Sudev
name: Mphako-Banda, Eunice Gogo
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Mathematics (math.GM)
subject: FOS: Mathematics
subject: 05C15, 05C38, 05C75

description: The closed neighbourhood $N[v]$ of a vertex $v$ of a graph $G$, consisting of at least one vertex from all colour classes with respect to a proper colouring of $G$, is called a rainbow neighbourhood in $G$. The minimum number of vertices and the maximum number of vertices which yield rainbow neighbourhoods with respect to a chromatic colouring of $G$ are called the minimum and maximum rainbow neighbourhood numbers, denoted by $r^-_χ(G)$, $r^+_χ(G)$ respectively. In this paper, by a colour, we mean a solid colour and by a transparent colour, we mean the fading of a solid colour. The fading numbers of a graph $G$, denoted by $f^-(G)$, $f^+(G)$ respectively, are the maximum number of vertices for which the colour may fade to transparent without a decrease in $r^-_χ(G)$ and $r^+_χ(G)$ respectively.
description: 6 Pages
Price and Purity Analysis for Illicit Drug: Data and Conceptual Issues
Creators: name: Caulkins, Jonathan P.
Publisher: name: Carnegie Mellon University
Year: 2005
Subjects: subject: Information Systems
subject: FOS: Computer and information sciences
subject: 160510 Public Policy
subject: FOS: Political science

description: Data on illicit drug purity and prices are invaluable but problematic. Purists argue they are unsuitable for economic analysis (Manski et al., 2001; Horowitz, 2001), but in reality they are used frequently (ONDCP 2001a, 2001b, 2004; Grossman, 2004). This paper reviews data and conceptual issues that people producing, analyzing, and consuming drug price and purity series should understand in order to reduce the likelihood of misinterpretation. It also identifies aspects of drug markets that are both poorly understood and relevant to some of these issues. They constitute a useful research agenda for health and law enforcement communities who would benefit from better data on the supply, availability, and use of illicit drugs.
Electromagnetic Production of the Hypertriton
Creators: name: Mart, T.
name: Tiator, L.
name: Drechsel, D.
name: Bennhold, C.
Publisher: name: arXiv
Year: 1996
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Kaon photoproduction on He3, gamma + He3 --> K+ + Hypertriton, is studied in the framework of the impulse approximation. Realistic He3 wave functions obtained as solutions of Faddeev equations with the Reid soft-core potential are used along with different Hypertriton wave functions. Results are compared for several elementary operator models, which can successfully describe the elementary kaon production off the proton up to a photon lab energy of k = 2.2 GeV. It is found that the corresponding cross sections are small, of the order of several nanobarns. It is also shown that the influence of Fermi motion is important, while the effect of different off-shell assumptions on the cross section is not too significant.
description: 39 pages in RevTeX including 8 Postscript figures. Replaced with the version accepted in Nucl. Phys. A