cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Do the mildly superluminal VLBI knots exclude ultrarelativistic blazar jets?
Creators: name: Gopal-Krishna
name: Dhurde, Samir
name: Wiita, Paul J.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We compute the effective values of apparent transverse velocity and flux boosting factors for the VLBI radio knots of blazar jets, by integrating over the angular distributions of these quantities across the widths of jets with finite opening angles but constant velocities. For high bulk Lorentz factors (Gamma > 10) variations across the jet can be quite large if the opening angle, omega, is even a few degrees on sub-parsec scales. The resulting apparent speeds are often much lower than those obtained from the usual analyses that ignore the finite jet opening angles. We can thus reconcile the usually observed subluminal or mildly superluminal speeds with the very high (>~ 20) Gamma factors, required by the inverse Compton origin and rapid variability of TeV fluxes, as well as by intraday radio variability. Thus it is possible to associate the VLBI radio knots directly with shocks in the ultra-relativistic main jet flow, without invoking very rapid jet deceleration on parsec scales, or extremely unlikely viewing angles.
description: 10 pages, 1 figure, to appear in ApJ Letters, Nov. 10 2004 issue
On the principal eigenvalue of the truncated Laplacian, and submanifolds with bounded mean curvature
Creators: name: Bessa, Gregório Pacelli F.
name: Jorge, Luquésio Petrola de M.
name: Mari, Luciano
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: Differential Geometry (math.DG)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics

description: In this paper, we study the principal eigenvalue $μ(\mathscr{F}_k^-,E)$ of the fully nonlinear operator
 \[
 \mathscr{F}_k^-[u] = \mathcal{P}_k^-(\nabla^2 u) - h |\nabla u|
 \] on a set $E \Subset \mathbb{R}^n$, where $h \in [0,\infty)$ and $\mathcal{P}_k^-(\nabla^2 u)$ is the sum of the smallest $k$ eigenvalues of the Hessian $\nabla^2 u$. We prove a lower estimate for $μ(\mathscr{F}_k^-,E)$ in terms of a generalized Hausdorff measure $\mathscr{H}_Ψ(E)$, for suitable $Ψ$ depending on $k$, moving some steps in the direction of the conjecturally sharp estimate
 \[
 μ(\mathscr{F}_k^-,E) \ge C \mathscr{H}^k(E)^{-2/k}.
 \] The theorem is used to study the spectrum of bounded submanifolds in $\mathbb{R}^n$, improving on our previous work in the direction of a question posed by S.T. Yau. In particular, the result applies to solutions of Plateau's problem for CMC surfaces.
description: 17 pages, typos corrected. Accepted in Matem\'atica Contempor\^anea, volume in honor of Renato Tribuzy for his 75th birthday. Package axessibility included to make the paper available to visually impaired people
El proceso de anulacion del Reglamento de redorma del sistema de apoyo al algodon en la UE
Creators: name: Ramos Real, Fernando
name: Gallardo Cobos, Rosa
name: Ramos Real, Fernando
name: Gallardo Cobos, Rosa
Publisher: name: Unknown
Year: 2007
Subjects: subject: Crop Production/Industries
subject: Environmental Economics and Policy
subject: reforma de la PAC
subject: principio de proporcionalidad
subject: reforma del regimen de apoyo al algodon
subject: CAP reform
subject: principle of proporcionality
subject: reform of the support for cotton scheme.

description: En la actual situacion de incertidubre y cuestionamiento de la politica agraria europea, y de estricta rigidez en el presupuesto communitario, resulta especialmente pertinente analizar la coherencia y eficacia de los instrumentos que la PAC disena para alcanzar sis objetivos. En este contexto se presenta en este articulo el caso de la anulacion del Regimen de apoyo al algodon en septiembre de 2006. La sentencia del Tribunal de Justicaia Europeo anulanda por primera vez un Reglamento Base invita a reflexionar en cuante a la coherencia y eficacia de esta politica agraria, ya que las medidad aprobadas son "manifiestamenta inadecuadas" para alcanzar el objetivo que para este cultivo se pretendia. Los argumentos economicos que se utilizan en este articulo proceden de los resultados del estudio de impacto socioeconomico en el que se apoyo el recurso presentado por Espana, del que son tambien autores los firmantes de este articulo. Se presentan algunos datos correspondentes a la Campana de algodon 2006-2007 que vienen a avalar las previsiones contendidas en el citado estudio...Given the current situation of uncertainty and questioning of the European Agricultural Policy, and given the tightness in the EU's budget, it seems particularly relevant to analyze the coherence and effectiveness of CAP's instruments to reach its objectives. Given this context, we deliver this paper as a result of the annulation by the European Court of Justice in September 2006 of the cotton support Reform (2004). This decision canceling for the first time a Basic Regulation, give us an opportunity to think about the coherence and efficiency of this Agricultural Policy, since it recognizes that the above mentioned reform harms the Principle of Proportionality. In other words, it considers that the approved measures are "absolutely inadequate" to attain its alleged objective. The economic reasoning used in this communication originates from the results of the socioeconomic impact study that Spain used to sustain its allegation; a document which we both co-authored. We also present some data of the 2006-2007 cotton crop annual report which support the predictions of the above mentioned study.
Topics on Hydrodynamic Model of Nucleus-Nucleus Collisions
Creators: name: Hama, Y.
name: Kodama, T.
name: Socolowski, O.
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: A survey is given on the applications of hydrodynamic model of nucleus-nucleus collisons, focusing especially on i) the resolution of hydrodynamic equations for arbitrary configurations, by using the smoothed-particle hydrodynamic approach; ii) effects of the event-by-event fluctuation of the initial conditions on the observables; iii) decoupling criteria; iv) analytical solutions; and others.
description: 30 pages, 29 figures; corrected typos
Distribucion territorial de las ayudas directas de la Politica Agraria Comun en Espana
Creators: name: Ribas Alvarez, Alfonso
name: Sineiro Garcia, Francisco
name: Lorenzana Fernandez, Roberto
name: Ribas Alvarez, Alfonso
name: Sineiro Garcia, Francisco
name: Lorenzana Fernandez, Roberto
Publisher: name: Unknown
Year: 2007
Subjects: subject: Demand and Price Analysis
subject: Financial Economics
subject: ayudas directas
subject: PAC
subject: distribucion territorial
subject: Direct aids
subject: CAP
subject: territorial distribution

description: Se analiza la distribucion de las ayudas directas de la Politica Agraria Comun (PAC) en Espana a escala provincial a partir de una base de datos individualizada de las ayudas PAC en el ano 2003 y de los microdatos del censo agraria de 1999. La distribucion de las ayudas directas es muy desigual tanto en su importe global y medio como con relacion a otros indicadores (SAU, UTA o VAB). Las disparidades entre provincias en los valores medios son de 6 a 1 para la ayuda media, llegando a ser de 18 a 1 para el importante percibido por Unidad de Trabajo Ano (UTA), aunque se reduce hasta 2, 7 a 1 para la ayuda por Superfivie Agraria Util (SAU) entre los grupos extremos. Se han establecido tres grandes areas en el nivel de las ayudas percibidas, resultando situacdas las provincias con monores importres medios en el areas mediterranea, el cantabrico y el noroeste peninsular, mientras que las de valores mas elevados estan en el sur en el eje Cordoba-Cadiz y en el norte por gran parte de Castilla Leon (excluyendo las provincias de Leon y Zamora), Huesca, Badajoz, Alava y Guadalajara. La variabilidad en el importe de las ayudas esta relacionada con el tamano fisico y economoico de las explotaciones, asi como por las orientaciones productivas, siendo las mas determinantes en sentido positivo la proporcion de superficie ocupada por el olivar y de modo negativo las de citricos y otros frutales...This paper analyses the distribution of direct payments in Spain at a provincial level. It is based on the individual data of payments if 2003 and the agricultural census of 1999. The distribution of direct payments is very uneven both in total amount, mean by producer and in relation to other structural indicators. The differences among provinces are 6 to 1 for the mean values by producer and up to 18 to 1 for the mean value by working unit. There are established three mean areas by the level of payments. The area with the lowest levels is situated in the Mediterranean and in the North-Northwest provinces. The highest levels are on the axe Cordoba-Cadiz and in part of Castilla-Leon, Huesca, Badajoz, Alava and Guadalajara. The size is the most determinant factor in the variability of payments, while the relative area occupied by the olive trees is the main factor among the productions.
Gravitation in terms of observables 2: the algebra of fundamental observables
Creators: name: Gambini, Rodolfo
name: Rastgoo, Saeed
name: Pullin, Jorge
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In a previous paper, we showed how to use the techniques of the group of loops to formulate the loop approach to gravity proposed by Mandelstam in the 1960's. Those techniques allow to overcome some of the difficulties that had been encountered in the earlier treatment. In this approach, gravity is formulated entirely in terms of Dirac observables without constraints, opening attractive new possibilities for quantization. In this paper we discuss the Poisson algebra of the resulting Dirac observables, associated with the intrinsic components of the Riemann tensor. This provides an explicit realization of the non-local algebra of observables for gravity that several authors have conjectured.
description: 21 pages, RevTex, 4 figures
Matrix Model Description of Laughlin Hall States
Creators: name: Cappelli, A.
name: Riccardi, M.
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We analyze Susskind's proposal of applying the non-commutative Chern-Simons theory to the quantum Hall effect. We study the corresponding regularized matrix Chern-Simons theory introduced by Polychronakos. We use holomorphic quantization and perform a change of matrix variables that solves the Gauss law constraint. The remaining physical degrees of freedom are the complex eigenvalues that can be interpreted as the coordinates of electrons in the lowest Landau level with Laughlin's wave function. At the same time, a statistical interaction is generated among the electrons that is necessary to stabilize the ground state. The stability conditions can be expressed as the highest-weight conditions for the representations of the W-infinity algebra in the matrix theory. This symmetry provides a coordinate-independent characterization of the incompressible quantum Hall states.
description: 31 pages, large additions on the path integral and overlaps, and on the W-infinity symmetry
Sparse metapiles for shear wave attenuation in half-spaces
Creators: name: Celli, Paolo
name: Nunzi, Ilaria
name: Calabrese, Andrea
name: Lenci, Stefano
name: Daraio, Chiara
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: We show that shear waves traveling towards the surface of a half-space medium can be attenuated via buried one-dimensional arrays of resonators -- here called metapiles -- arranged according to sparse patterns around a site to be isolated. Our focus is on shear waves approaching the surface along a direction perpendicular to the surface itself. First, we illustrate the behavior of metapiles, both experimentally and numerically, using 3D printed resonators embedded in an acrylic plate. Then, via numerical simulations, we extend this idea to the case study of an idealized soil half-space, and elucidate the influence of various design parameters on wave attenuation. Results of this work demonstrate that significant wave attenuation can be achieved by installing sparse resonating piles around a selected site on the free surface of the medium, rather than placing resonators directly underneath that same site. This work might have implications in metamaterial-based wave attenuation applications across scales.
Los impactos de la abolicion de la PAC en la economia espanola, europea y mundial: resultados de una simulacion con un modelo de equilibrio general aplicado
Creators: name: Argudo, Ramon Ramos
name: Philippidis, George
name: Choliz, Julio Sanchez
name: Argudo, Ramon Ramos
name: Philippidis, George
name: Choliz, Julio Sanchez
Publisher: name: Unknown
Year: 2007
Subjects: subject: Agribusiness
subject: Agricultural and Food Policy
subject: International Development
subject: equilibrio general computable
subject: Politica Agraria Comun
subject: comercio internacional agroalimentario
subject: GTAP
subject: Computable general equilibrium
subject: common agricultural policy
subject: agricultural international trade

description: Este trabajo pretende evaluar cuantitativamente el impacto economico a largo plazo de la abolicion de la Politica Agraria Comun (PAC), con especial enfasis en Espana. Para realizar nuestro analisis, hemos empleado el modelo de equilibrio general computable del Proyecto de Analisis de Comercio Global (GTAP) y la version 6 de su base de datos, que representa la economia global en 2001. Para caracterizar la abolicion de la PAC hemos eliminado unilateralmente todos los apoyos domesticos de la UE que constituyen el primer pilar de la PAC. Adicionalmente, hemos eliminado los subsidios a la exportacion agroalimentaria, asi como los arancles sobre las importaciones agroalimentarias, todo ello conre specto al equilibrio en el ano de referencia 2001. Examinando las medidas de bienestar tradicionalmente empleadas en los modelos de equilibrio general, efectos en terminos de eficiencia asignativa y relacion de intercambio, el resultado subyacente es que Espana mejoraria levemente su bienestar ante una eliminacion de la PAC bajo determinados supuestos del modelo...The aim of this paper is to quantitatively assess the long run economic impact of Common Agricultural Policy (CAP) abolition, where in particular, we focus on the Spanish economy. To carry out our analysis, we employ the Global Trade Analysis Project (GTAP) computable general equilibrium model with accompanying version 6 data. In its present incarnation, the data captures the global economy in 2001. To cahracterise abolition of the CAP we unilaterally remove all pillar one CAP support. In addition, we eliminate export subsidies and EU import tariff which affect primary agriculture and food processing sectors, all of it according to the benchmark equilibrium in 2001. Examining traditional general equilibrium welfare measures of market efficiency and terms of trade effects, our underlying result is that Spain realizes a small welfare gain from removal of the CAP, although this finding carries a caveat.
Family voices : analyses of talk in families with Alzheimer’s disease or a related disorder
Creators: name: Purves, Barbara Anne
Publisher: name: University of British Columbia
Year: 2010

description: It is widely recognized that communication difficulties pose significant problems for family members of people with disorders of progressive cognitive decline, such as Alzheimer’s disease (AD). To date, however, relatively few studies have explored these problems in the context of everyday conversation in family life. The goal of this qualitative study was to explore changes in family conversation associated with a diagnosis of progressive cognitive decline, the meanings associated with those changes for family members, and the implications of those meanings for the family as a unit. The project comprises case studies of two families, one including a woman with AD, her husband, and their three adult children, the other including a woman with nonfluent progressive aphasia, her husband, and their four adult children. Methodology was based on symbolic interactionism and conversation analysis, exploring meanings both as conscious reflection and also as constructions of everyday talk. Constant comparative analysis of interviews conducted with each family member identified meanings that he or she gave to the diagnosis and changes associated with it, highlighting how consistencies and contradictions in those meanings were interwoven within each family unit. Analysis of audiorecorded conversations between the diagnosed person and other family members highlighted how those meanings were constructed in their talk together. For the family with AD, a key finding, discussed in terms of positioning theory, was how the family negotiated changing roles through everyday talk; for the family with progressive aphasia, a key finding, discussed in terms of theoretical considerations of silence, was how family interpreted and accommodated to their affected kin’s diminishing talk. Communication accommodation theory provided a framework for discussing the findings for both families, exploring the ways in which members sought to maintain conversational coherence while respecting relational demands for politeness. Finally, because each family was considered as a unit, the findings offer new insights into the nature of family care and support in the context of disease. Together, these case studies inform our understanding of dilemmas, challenges, and strategies for families coming to terms with progressive cognitive decline; the relevance of these findings for clinical practitioners is also addressed.
Guided Policy Search using Sequential Convex Programming for Initialization of Trajectory Optimization Algorithms
Creators: name: Kim, Taewan
name: Elango, Purnanand
name: Malyuta, Danylo
name: Acikmese, Behcet
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: Robotics (cs.RO)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Nonlinear trajectory optimization algorithms have been developed to handle optimal control problems with nonlinear dynamics and nonconvex constraints in trajectory planning. The performance and computational efficiency of many trajectory optimization methods are sensitive to the initial guess, i.e., the trajectory guess needed by the recursive trajectory optimization algorithm. Motivated by this observation, we tackle the initialization problem for trajectory optimization via policy optimization. To optimize a policy, we propose a guided policy search method that has two key components: i) Trajectory update; ii) Policy update. The trajectory update involves offline solutions of a large number of trajectory optimization problems from different initial states via Sequential Convex Programming (SCP). Here we take a single SCP step to generate the trajectory iterate for each problem. In conjunction with these iterates, we also generate additional trajectories around each iterate via a feedback control law. Then all these trajectories are used by a stochastic gradient descent algorithm to update the neural network policy, i.e., the policy update step. As a result, the trained policy makes it possible to generate trajectory candidates that are close to the optimality and feasibility and that provide excellent initial guesses for the trajectory optimization methods. We validate the proposed method via a real-world 6-degree-of-freedom powered descent guidance problem for a reusable rocket.
description: Presented in American Control Conference (ACC) 2022
Running the gamut of high energy nuclear collisions
Creators: name: Schenke, Bjoern
name: Shen, Chun
name: Tribedy, Prithwish
Publisher: name: arXiv
Year: 2020
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We present calculations of bulk properties and multiparticle correlations in a large variety of collision systems within a hybrid formalism consisting of IP-Glasma initial conditions, MUSIC viscous relativistic hydrodynamics, and UrQMD microscopic hadronic transport. In particular, we study heavy ion collisions at the Large Hadron Collider (LHC), including Pb+Pb, Xe+Xe, and O+O collisions, and Au+Au, U+U, Ru+Ru, Zr+Zr, and O+O collisions at the Relativistic Heavy Ion Collider (RHIC). We further study asymmetric systems, including p+Au, d+Au, $^3$He+Au, and p+Pb collisions at various energies as well as p+p collisions at 0.5 and 13 TeV. We describe experimental observables in all heavy ion systems well with one fixed set of parameters, validating the energy and system dependence of the framework. Many observables in the smaller systems are also well described, although they test the limits of the model. Calculations of O+O collisions provide predictions for potential future runs at RHIC and LHC.
description: 24 pages, 20 figures
Modelizacion de primas para un seguro de ingresos en el freson de Huelva
Creators: name: Manzanares, Salomon Aguado
name: Colmenero, Alberto Garrido
name: Manzanares, Salomon Aguado
name: Colmenero, Alberto Garrido
Publisher: name: Unknown
Year: 2007
Subjects: subject: Agribusiness
subject: Agricultural and Food Policy
subject: Agricultural Finance
subject: modelizacion
subject: seguros agrarios
subject: freson
subject: seguro de ingresos
subject: gestion de riesgos en la agricultura
subject: simulacion Monte-Carlo
subject: modeling
subject: agricultural insurance
subject: strawberries
subject: revenue insurance
subject: agricultural risk management
subject: Monte Carlo simulation

description: Espana es el tercer productor y el primer exportador mundial de freson. Toda esta produccion esta mayoritariamente concentrada en una zona, convirtiendo a Huelva en la mas importante regon exportadora de freson del mundo. En base de las investigaciones realizadas, los instrumentos de gestion de riesgo vigentes para el sector no prestan un adecuado grado de satisfaccion para los agricultores que reclaman y reivindican un seguro que les proporcione una cobertura completa de los riesgos que soportan. El objectivo de la presente comunicacion es desarrollar un seguro de ingresos global que aglutine todos esos riesgos que soporta el freson, dando adecuada en la informacion suministrada por empresas que representan el 44 por ciento de la produccion provincial, replica el modelo de ingresos de cada una de ellas y a traves de simulacion Monte-Carlo determina el nivel de proma pura para diversas estrategias aseguradoras. Seria viable un cambio de metodologia pasando de un seguro de danos a un seguro de ingresos, donde las opciones mas factibles seria cobertura del 100 por ciento o franquincia relativa del 30 por ciento...Spain is the world's third largest producer and major exporter of strawberries. Production is primarily concentrated within a single zone, which has made Huelva the most important strawberry-exporting region in the world. Research projects show that risk-management instruments in this sector do not offer strawberry farmers an adequate degree of satisfaction, and they are demanding an insurance policy that will offer them full cover for the risks that they run. The objective of the study presented here was to develop a global income insurance product that gathers together all the risks borne by the strawberry sector, responding sufficiently to the accidents and other sources of loss that affect this industry. The insurance product, whose design is based on the information supplied by companies that are responsible for 44 percent of production in the province, copies the income model of each individual company, and by means of a Monte Carlo simulation determines the pure premium level appropriate for different insurance strategies. A viable option would to change the multiple-percil insurance to a revenue insurance, with 100 percent guarantee and relative deductible of 30 percent.
Structural properties and stability of defected ZnSe/GaAs(001) interfaces
Creators: name: Stroppa, A.
name: Peressi, M.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Accurate ab-initio pseudopotential calculations within density functional theory in the LDA approximation have been performed for structural properties and stability of ZnSe/GaAs(001) defected heterostructures. There is a strong experimental evidence that ZnSe/GaAs heterostructures with minimum stacking fault density are related to the presence of a substantial concentration of Ga vacancies at interface. In order to gain insights into the still unknown microscopic maechanism governing their formation and stability, we compared the relative stability of some simple selected interface configurations, chosen taking into account charge neutrality prescription and allowing the presence of Ga vacancy next to the interface. Remarkably, our results show that, under particular thermodynamic conditions, some interfaces with vacancies are favoured over undefected ones.
description: 19 pages, 5 figures, PDF only; in press on Comp.Mat.Sci
ALFRED: Virtual Memory for Intermittent Computing
Creators: name: Maioli, Andrea
name: Mottola, Luca
Publisher: name: arXiv
Year: 2021
Subjects: subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences

description: We present ALFRED: a virtual memory abstraction that resolves the dichotomy between volatile and non-volatile memory in intermittent computing. Mixed-volatile microcontrollers allow programmers to allocate part of the application state onto non-volatile main memory. Programmers are therefore to explore manually the trade-off between simpler management of persistent state against the energy overhead for non-volatile memory operations and intermittence anomalies due to re-execution of non-idempotent code. This approach is laborious and yields sub-optimal performance. We take a different stand with ALFRED: we provide programmers with a virtual memory abstraction detached from the specific volatile nature of memory and automatically determine an efficient mapping from virtual to volatile or non-volatile memory. Unlike existing works, ALFRED does not require programmers to learn a new programming model or language syntax, while the mapping is entirely resolved at compile-time, reducing the run-time energy overhead. We implement ALFRED through a series of program machine-level code transformations. Compared to existing systems, we demonstrate that ALFRED reduces energy consumption by up to two orders of magnitude given a fixed workload. This enables the workloads to finish sooner, as the use of available energy shifts from ensuring forward progress to useful application processing.
Quantum backflow for many-particle systems
Creators: name: Barbier, Maximilien
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum backflow is the classically-forbidden effect pertaining to the fact that a particle with a positive momentum may exhibit a negative probability current at some space-time point. We investigate how this peculiar phenomenon extends to many-particle systems. We give a general formulation of quantum backflow for systems formed of $N$ free nonrelativistic structureless particles, either identical or distinguishable. Restricting our attention to bosonic systems where the $N$ identical bosons are in the same one-particle state allows us in particular to analytically show that the maximum achievable amount of quantum backflow in this case becomes arbitrarily small for large values of $N$.
description: 12 pages, 2 figures
Classical information transmission capacity of quantum black holes
Creators: name: Adami, Christoph
name: Steeg, Greg Ver
Publisher: name: arXiv
Year: 2004
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The fate of classical information incident on a quantum black hole has been the subject of an ongoing controversy in theoretical physics, because a calculation within the framework of semi-classical curved-space quantum field theory appears to show that the incident information is irretrievably lost, in contradiction to time-honored principles such as time-reversibility and unitarity. Here, we show within this framework embedded in quantum communication theory that signaling from past to future infinity in the presence of a Schwarzschild black hole can occur with arbitrary accuracy, and thus that classical information is not lost in black hole dynamics. The calculation relies on a treatment that is manifestly unitary from the outset, where probability conservation is guaranteed because black holes stimulate the emission of radiation in response to infalling matter. This stimulated radiation is non-thermal, and contains all of the information about the infalling matter, while Hawking radiation contains none of it.
description: 18 pages, 2 figures. Uses iopart.cls
Ethnicity on the line : the case of Mixteco workers in Tijuana’s labour market
Creators: name: Méndez, Alberto
Publisher: name: University of British Columbia
Year: 2010

description: This dissertation examines the changing social identity of a Mexican indigenous immigrant community in Tijuana, Mexico, against the backdrop of rapid export-oriented industrialization along Mexico's northern border. The group of indigenous immigrants in question are the Mixtecos from southern Mexico, who began to settle in Tijuana in the early 1960s. Living for the most part in impoverished urban settlements or colonias, Tijuana's Mixteco community has been undergoing a process of change associated with the functional role Mexico's northern border is playing within the global economy. In recent years, this community has gained access to employment within Tijuana's maquiladora industry, the driving force behind the local labour markets. This study explores how Mixtecos' involvement in this labour market is having an impact on their ethnic identity. Based on qualitative research and fieldwork conducted in Tijuana, this dissertation finds that, while members of Tijuana's Mixteco community have been gradually drawn into to the maquiladora labour market, they have, in fact, been reconstructing their ethnic identity. Because of the demands of the industry and of Tijuana's socio-cultural milieu, Mixtecos who have gained access to maquiladora employment have been concealing their ethnicity, while adopting non-indigenous mestizo traits and assuming class rather than ethnic positions. Throughout this process, Mixteco factory workers have been retreating from their ethnic community to focus on individual and family affairs. These findings thus depart from the well-established scholarly literature dealing with Mixteco out-migration which argues that, in the displaced context outside the Mixteca heartland, Mixteco immigrants in northern Mexico and the U.S. have acquired an ethnic-based identity, forged on shared culture and on common negative experiences. Throughout this dissertation, ethnicity is viewed in line with the constructivist paradigm that conceives ethnicity as a dynamic form of social identity arising from particular structural circumstances and specific contexts. The examination has thus required attention on different levels of analysis, from a macro perspective dealing with the structural conditions explaining the expansion of capitalism in Mexico, the Mixteco outmigration, and the disenfranchisement of indigenous peoples in Mexican society, to a micro inspection of the everyday social interactions of Mixteco women and men in specific settings (i.e. the factories). This dissertation therefore expands the literature on the Mexican maquiladoras, which has given only slight attention to matters of ethnicity.
Eficiencia tecnica y medioambiental de las explotaciones vinicolas ecologicas versus convencionales
Creators: name: Arandia Miura, Amaia
name: Aldanondo-Ochoa, Ana
name: Arandia Miura, Amaia
name: Aldanondo-Ochoa, Ana
Publisher: name: Unknown
Year: 2007
Subjects: subject: Agribusiness
subject: Environmental Economics and Policy
subject: Production Economics
subject: eficiencia
subject: agricultura ecologica
subject: impacto ambiental
subject: efficiency
subject: organic farming
subject: environmental impact

description: Los programas de certificacion ecologica no son sino programas de eco-etiquetado, maediante los cuales se certifica que los productos englobados en estat etiquetas cumplen una determinada normatica, que persigue funamentalmente la reduccion del impacto ambiental provocado por la actividad agraria. Mediante la utilizacion de metodos no parametricos de medidas de eficiencia (DEA), en este trabajo se pretende comparar la eficiencia tecnica de dos grupos de explotaciones cuyo cultivo principal es la vina, de dos sistemas de produccion agraria, agricultura convencional y ecologica. Esto se va a llevar a cabo desde dos perspectivas diferentes: considerando exc;usivamente la relacion entre factores y producto, en una primera fase, e incluyendo los impactos ambientales, en la segunda. la comparacion de los resultados obtenidos en estos escenarios nos permite avanzar algunas conclusiones sobre la eficiencia de la agricultura ecologica en condiciones de secano y cultivos perennes...Organic certification programs are eco-labelling programs, by which it is certified that these products comply with the regulations, who main aim is a reduction of the environmental impact provoked by agriculture. By means of DEA, in this work we calculate and compare the technical efficiency of two samples of conventional and organic vineyards, from two different perspectives: in the first instance, the relationship between inputs and outputs is considered, exclusively; in the first instance, the relationship between impacts arising from the activity are also included. The comparison of the results obtained in these two scenarios allows us to draw some conclusions on the efficiency of organic farming in dry-farming conditions and perennial crops.
Quantum information with continuous variables
Creators: name: Braunstein, Samuel L.
name: van Loock, Peter
Publisher: name: arXiv
Year: 2004
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum information is a rapidly advancing area of interdisciplinary research. It may lead to real-world applications for communication and computation unavailable without the exploitation of quantum properties such as nonorthogonality or entanglement. We review the progress in quantum information based on continuous quantum variables, with emphasis on quantum optical implementations in terms of the quadrature amplitudes of the electromagnetic field.
description: accepted for publication in Reviews of Modern Physics
Robust Maximum Capture Facility Location under Random Utility Maximization Models
Creators: name: Ta, Anh Thuy
name: Dam, Tien Thanh
name: Mai, Tien
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: We study a robust version of the maximum capture facility location problem in a competitive market, assuming that each customer chooses among all available facilities according to a random utility maximization (RUM) model. We employ the generalized extreme value (GEV) family of models and assume that the parameters of the RUM model are not given exactly but lie in convex uncertainty sets. The problem is to locate new facilities to maximize the worst-case captured user demand. We show that, interestingly, our robust model preserves the monotonicity and submodularity from its deterministic counterpart, implying that a simple greedy heuristic can guarantee a (1-1/e) approximation solution. We further show the concavity of the objective function under the classical multinomial logit (MNL) model, suggesting that an outer-approximation algorithm can be used to solve the robust model under MNL to optimality. We conduct experiments comparing our robust method to other deterministic and sampling approaches, using instances from different discrete choice models. Our results clearly demonstrate the advantages of our roust model in protecting the decision-maker from bad-case scenarios.
title: Evaluierung von WEB 2.0 Anwendungen zur Vermarktung im Immobilienbereich unter besonderen Berücksichtigung von Österreich im Vergleich zu den USA
Creators: name: Redl, Robert
Publisher: name: TU Wien
Year: 2017
Subjects: subject: Immobilienverwaltung
subject: Social Media
subject: Kommunikation
subject: Netzwerk
subject: Internet

description: Die Kernidee des Web 2.0 war es, den Konsumenten einen Raum zu geben, um sich zu präsentieren und auch, um miteinander kommunizieren zu können. Im Rahmen des Web 2.0 entwickelte sich das Internet weg von einer starren Informationsquelle und wurde zu einer Art interaktivem Mitmachmedium. So konnten Projekte, wie Wikipedia oder Facebook in kürzester Zeit Millionen von Nutzern verbuchen. Viele der neuen Tools wie Instagram, Snapchat und Twitter werden am Maklern in den USA als bidirektionales Kommunikationsinstrument mit den potentiellen Kunden gesehen. Die Netzwerke werden mehr als nur für die reine Imagepflege der Unternehmen gesehen und bieten darüber hinaus eine Kommunikationsplattform mit Kunden unabhängig von Zeit und Ort und überwinden alle Mikro und Makroebenen der Interaktion. Neue Absatzmärkte werden kostengünstig und ressourcensparend erschlossen und alte überholte und ineffiziente Arbeitsabläufe abgelegt. Vor allem im urbanen Kontext verwenden die Makler Tools wie Instagram und Snapchat um ihre Immobilien schnell zu promoten. Umsätze der Makler sind auch nach Bereinigung durch das BIP und Kaufpreisindex Anpassung signifikant höher als in Österreich. Abschlüsse über soziale Netzwerke nehmen signifikant zu und bilden derzeit 5% ihres Umsatzes und zusammen mit der klassischen Homepage, jedoch immer auf den Stand des WEB2.0 gebracht sogar 20% des Umsatzes. Fast jede Webseite der Makler hat Verknüpfungen zu allen derzeit Relevanten sozialen Netzwerken. Die digitale Metamorphose schreitet voran; wird sich der Markt durch Evolution - vor allem technologische- oder revolutioniert, in Form von soziotechnischen (Web 2.0) - Entwicklungen wegrationalisiert bzw. verändert. Wie halten die österreichischen Makler den Innovationsdruck stand und wann geben sie nach.
La eficiencia en explotaciones ganaderas de dehesa: una aproximacion DEA al papel de la sostenibilidad y de las subvenciones comunitarias
Creators: name: Escribano, M.
name: Gaspar, P.
name: Mesias, F.J.
name: Pulido, F.
name: Martinez-Carrasco, F.
name: Escribano, M.
name: Gaspar, P.
name: Mesias, F.J.
name: Pulido, F.
name: Martinez-Carrasco, F.
Publisher: name: Unknown
Year: 2007
Subjects: subject: Farm Management
subject: Land Economics/Use
subject: Livestock Production/Industries
subject: dehesa
subject: ganaderia extensiva
subject: eficiencia tecnica
subject: Rangelands
subject: extensive livestock
subject: technical efficiency

description: En el presente trabajo se recogen los resultados de una investigacion en la que se estudia la eficiencia tecnica de una muestra de explotaciones extensivas en sistemas de dehesa empleando la tecnica de analisis no parametrico DEA (Analisis Envolvente de Datos). Se determina la influencia de las subvenciones de la PAC, consideradas como un output mas, en la eficiencia de estas empresas. Ademas, se identifican las tipologias de lsa explotaciones que se corresponden con mayores o menores indices de efiencias, abordandose un analisis combinado de indices de eficiencia e indices de sostenibilidad cuya finalidad es comparar la gestion eficiente con la gestion sostenible...This paper shows the results of a research analyzing the technical efficiency of a sample of extensive dehesa farms. The technique use has been a non-parametric DEA (Data Envelopment Analysis). WE have determined the influence in the farms; efficiency of CAP's subsidies (considered as another input). Different typologies of farms have been studied, identifying which of them show the highest and lowest efficiency levels. Finally, the paper tries to mix efficiency levels and sustainability indicators, in order to compare efficient management vs. sustainable management.
Czynniki wpływające na wysokość polskiej składki do ONZ ds. Wyżywienia i Rolnictwa
Creators: name: Krzyżanowski, Julian Tadeusz
name: Krzyżanowski, Julian Tadeusz
Publisher: name: Unknown
Year: 2013
Subjects: subject: Agricultural and Food Policy
subject: Financial Economics
subject: Polish contribution
subject: United Nations Organization
subject: FAO
subject: capacity to pay
subject: U.N. budget
subject: / polska składka
subject: zdolność płatnicza
subject: budżet ONZ

description: Scale of contribution to different United Nations organizations is based on similar principles. The evolution of appropriating the contribution, methods of apportionment, needs and possibilities of corrections have been presented in the paper. / Synopsis. Skala składek do różnych organizacji Narodów Zjednoczonych oparta jest na podobnych zasadach. W artykule przedstawiono ewolucję ustalania składek, metodykę wyznaczania oraz potrzeby i możliwości korekty wysokości składek.
Roughness correction to the Casimir force : Beyond the Proximity Force Approximation
Creators: name: Neto, Paulo A. Maia
name: Lambrecht, Astrid
name: Reynaud, Serge
Publisher: name: arXiv
Year: 2004
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We calculate the roughness correction to the Casimir effect in the parallel plates geometry for metallic plates described by the plasma model. The calculation is perturbative in the roughness amplitude with arbitrary values for the plasma wavelength, the plate separation and the roughness correlation length. The correction is found to be always larger than the result obtained in the Proximity Force Approximation.
description: 7 pages, 3 figures, v2 with minor changes
A Longitudinal Method for Simultaneous Whole-Brain and Lesion Segmentation in Multiple Sclerosis
Creators: name: Cerri, Stefano
name: Hoopes, Andrew
name: Greve, Douglas N.
name: Mühlau, Mark
name: Van Leemput, Koen
Publisher: name: arXiv
Year: 2020
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: In this paper we propose a novel method for the segmentation of longitudinal brain MRI scans of patients suffering from Multiple Sclerosis. The method builds upon an existing cross-sectional method for simultaneous whole-brain and lesion segmentation, introducing subject-specific latent variables to encourage temporal consistency between longitudinal scans. It is very generally applicable, as it does not make any prior assumptions on the scanner, the MRI protocol, or the number and timing of longitudinal follow-up scans. Preliminary experiments on three longitudinal datasets indicate that the proposed method produces more reliable segmentations and detects disease effects better than the cross-sectional method it is based upon.
A Dynamic Mode Decomposition Extension for the Forecasting of Parametric Dynamical Systems
Creators: name: Andreuzzi, Francesco
name: Demo, Nicola
name: Rozza, Gianluigi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 37M05 65P10 35A17

description: Dynamic mode decomposition (DMD) has recently become a popular tool for the non-intrusive analysis of dynamical systems. Exploiting Proper Orthogonal Decomposition (POD) as a dimensionality reduction technique, DMD is able to approximate a dynamical system as a sum of spatial basis evolving linearly in time, thus enabling a better understanding of the physical phenomena and forecasting of future time instants. In this work we propose an extension of DMD to parameterized dynamical systems, focusing on the future forecasting of the output of interest in a parametric context. Initially all the snapshots -- for different parameters and different time instants -- are projected to a reduced space; then DMD, or one of its variants, is employed to approximate reduced snapshots for future time instants. Exploiting the low dimension of the reduced space the predicted reduced snapshots are then combined using regression techniques, thus enabling the possibility to approximate any untested parametric configuration in future. This paper depicts in detail the algorithmic core of this method; we also present and discuss three test cases for our algorithm: a simple dynamical system with a linear parameter dependency, a heat problem with nonlinear parameter dependency and a fluid dynamics problem with nonlinear parameter dependency.
Struktury rynkowe a zmienność cen względnych w sektorze przetwórstwa przemysłowego i branży spożywczej krajów UE
Creators: name: Kufel, Justyna
name: Kufel, Justyna
Publisher: name: Unknown
Year: 2013
Subjects: subject: Agribusiness
subject: Agricultural Finance
subject: Demand and Price Analysis
subject: International Relations/Trade
subject: Research Methods/ Statistical Methods
subject: market structures
subject: relative price variability
subject: price-cost margin
subject: / struktury rynkowe
subject: zmienność cen względnych
subject: marża cenowo-kosztowa

description: Relative cross-country price volatility increases business risk and distorts efficient sector-level investment allocation. In order to answer the questions of “if” and “how” market structures affect relative price volatility, and using annual data from 14 manufacturing branches in 27 EU countries, the interaction of market structures and relative price variability was analyzed. In accordance with the markup pricing model, relative markups variability interacts with relative price variability in the EU countries. On the other hand, more intense interactions between relative markups changes and nominal exchange rate changes decrease relative price variability. Moreover, the indicators of market structures and relative price volatility for the food sector were compared with those in other sectors. / Synopsis. Zmienność cen względnych między krajami zwiększa ryzyko prowadzenia działalności gospodarczej oraz zakłóca efektywną alokację inwestycji. W artykule próbowano odpowiedzieć na pytanie, czy i w jaki sposób struktury rynkowe oddziałują na zmienność cen względnych w branżach sektora przetwórstwa przemysłowego. Wykorzystując dane roczne dotyczące 14 branż przetwórstwa w 27 krajach członkowskich UE, analizowano interakcje struktur rynkowych i zmienności cen względnych. Zgodnie z założeniami standardowego modelu szacowania marż okazało się, że wzrost zmienności marż względnych ma związek z większą zmiennością cen względnych między krajami. Wzrost interakcji między zmianami marż względnych i zmianami nominalnego kursy walutowego oddziałuje z kolei na spadek zmienności cen względnych. Sytuację w branży spożywczej przedstawiono na tle pozostałych analizowanych branż.