352 research outputs found
Cost of Production Loss for Long-term Disability due to Road Crashes
Traffic accidents leave lifelong after-effects and if the victim is disabled, they produce a production loss due to the differential in income that will be lost. This average value is very divergent in European countries, although there is consensus on cost components and valuation methods. However, many countries have legally standardised financial compensation so that it is calculated objectively and equitably for all those affected. This paper sets out the procedure for standardising the lost production cost of incapacitated road accident victims. An actuarial methodology relating to known inputs (age and salary) is used to obtain economic compensation for lost productivity. General principles and hypotheses are provided, and cases that require particular valuation are located. The standard cost thus calculated allows a homogeneous, fair and equitable compensation for all those involved in similar circumstances.</p
Factorization in spin systems under general fields and separable ground-state engineering
We discuss ground-state factorization schemes in spin S arrays with general quadratic couplings under general magnetic fields, not necessarily uniform or transverse. It is shown that, given arbitrary spin alignment directions at each site, nonzero XYZ couplings between any pair and fields at each site always exist such that the ensuing Hamiltonian has an exactly separable eigenstate with the spins pointing along the specified directions. Furthermore, by suitable tuning of the fields this eigenstate can always be cooled down to a nondegenerate ground state. It is also shown that in open one-dimensional systems with fixed arbitrary first-neighbor couplings at least one separable eigenstate compatible with an arbitrarily chosen spin direction at one site is always feasible if the fields at each site can be tuned. We demonstrate as well that in the vicinity of factorization, i.e., for small perturbations in the fields or couplings, pairwise entanglement reaches full range. Some noticeable examples of factorized eigenstates are unveiled. The present results open the way for separable ground-state engineering. A notation to quantify the complexity of a given type of solution according to the required control on the system couplings and fields is introduced.Instituto de Física La Plat
Factorization in spin systems under general fields and separable ground-state engineering
We discuss ground-state factorization schemes in spin S arrays with general quadratic couplings under general magnetic fields, not necessarily uniform or transverse. It is shown that, given arbitrary spin alignment directions at each site, nonzero XYZ couplings between any pair and fields at each site always exist such that the ensuing Hamiltonian has an exactly separable eigenstate with the spins pointing along the specified directions. Furthermore, by suitable tuning of the fields this eigenstate can always be cooled down to a nondegenerate ground state. It is also shown that in open one-dimensional systems with fixed arbitrary first-neighbor couplings at least one separable eigenstate compatible with an arbitrarily chosen spin direction at one site is always feasible if the fields at each site can be tuned. We demonstrate as well that in the vicinity of factorization, i.e., for small perturbations in the fields or couplings, pairwise entanglement reaches full range. Some noticeable examples of factorized eigenstates are unveiled. The present results open the way for separable ground-state engineering. A notation to quantify the complexity of a given type of solution according to the required control on the system couplings and fields is introduced.Instituto de Física La Plat
Non-transverse factorizing fields and entanglement in finite spin systems
We determine the conditions for the existence of non-transverse factorizing magnetic fields in general spin arrays with anisotropic XY Z couplings of arbitrary range. It is first shown that a uniform maximally aligned completely separable eigenstate can exist just for fields hs parallel to a principal plane and forming four straight lines in field space, with the alignment direction different from that of hs and determined by the anisotropy. Such state always becomes a non-degenerate ground state (GS) for sufficiently strong (yet finite) fields along these lines, in both ferromagnetic (FM) and antiferromagnetic (AFM) type systems. In AFM chains, this field coexists with the nontransverse factorizing field h′ s associated with a degenerate N´eel-type separable GS, which is shown to arise at a level crossing in a finite chain. It is also demonstrated for arbitrary spin that pairwise entanglement reaches full range in the vicinity of both hs and h′ s, vanishing at hs but approaching small yet finite side-limits at h′ s, which are analytically determined. The behavior of the block entropy and entanglement spectrum in their vicinity is also analyzed.Facultad de Ciencias ExactasInstituto de Física La Plat
Non-transverse factorizing fields and entanglement in finite spin systems
We determine the conditions for the existence of non-transverse factorizing magnetic fields in general spin arrays with anisotropic XY Z couplings of arbitrary range. It is first shown that a uniform maximally aligned completely separable eigenstate can exist just for fields hs parallel to a principal plane and forming four straight lines in field space, with the alignment direction different from that of hs and determined by the anisotropy. Such state always becomes a non-degenerate ground state (GS) for sufficiently strong (yet finite) fields along these lines, in both ferromagnetic (FM) and antiferromagnetic (AFM) type systems. In AFM chains, this field coexists with the nontransverse factorizing field h′ s associated with a degenerate N´eel-type separable GS, which is shown to arise at a level crossing in a finite chain. It is also demonstrated for arbitrary spin that pairwise entanglement reaches full range in the vicinity of both hs and h′ s, vanishing at hs but approaching small yet finite side-limits at h′ s, which are analytically determined. The behavior of the block entropy and entanglement spectrum in their vicinity is also analyzed.Facultad de Ciencias ExactasInstituto de Física La Plat
Factorización y criticalidad en sistemas de espines
El objetivo general de esta tesis es examinar el comportamiento crítico y las correlaciones cuánticas de sistemas cuánticos interactuantes -en particular de sistemas de espines- en función de un parámetro de control. Típicamente, los autoestados exactos de estos sistemas son estados entrelazados -cuanticamente correlacionados- aun en presencia de campos magnéticos externos. No obstante, bajo ciertas condiciones de los valores y orientaciones del campo aplicado, estos sistemas pueden poseer un estado fundamental exacto completamente separable. Este notable fenómeno es conocido como "factorización". En esta tesis se determinan y estudian las condiciones de existencia de campos factorizantes en sistemas finitos de espines con acoplamientos cuadráticos generales inmersos en campos no necesariamente uniformes o transversos. En particular, se demuestra que las ecuaciones derivadas permiten descubrir nuevos fenómenos críticos en sistemas con interacciones de tipo XYZ y XXZ, entre otros. Mediante un estudio riguroso del entrelazamiento en la vecindad de los puntos de factorización se muestra que estos se corresponden con verdaderos puntos críticos cuánticos en sistemas finitos. Finalmente, se discute cómo estos resultados posibilitan inducir fenómenos críticos y nuevas formas de frustración; así como permiten diseñar esquemas de ingeniería de estados separables, aptos para ser utilizados como estados iniciales en algoritmos cuánticos.The main goal of this thesis is to study the critical behavior and quantum correlation properties of interacting quantum systems -in particular of spin systems- when a control parameter is varied. The exact ground state (GS) of interacting spin systems in an external magnetic field is typically an entangled state, i.e., a state with quantum correlations. However, under certain conditions for an applied field these systems can possess a completely separable exact GS. This remarkable phenomenon is known as "factorization". In this thesis, we derive and study the conditions for the existence of factorization in finite spin arrays with general quadratic couplings immersed in magnetic fields, not necessarily uniform or transverse. In particular, it is shown that these equations allow for the determination of novel critical phenomena in systems with XYZ and XXZ-type couplings, among others. By rigorously studying the entanglement in the vicinity of factorization points it is proven that they correspond to quantum critical points in finite systems. We then discuss how these results enable the possibility to induce critical phenomena and new types of frustration. The present results also open the way for separable ground-state engineering, which can be useful for quantum information applications.Facultad de Ciencias Exacta
Factorization and criticality in finite XXZ systems of arbitrary spin
We analyze ground state (GS) factorization in general arrays of spinss_iwithXXZcouplings immersed in nonuniform fields. It is shown that an exceptionally degenerate set of completely separable symmetry-breaking GS's can arise for a wide range of field configurations, at a quantum critical point where all GS magnetization plateaus merge. Such configurations include alternating fields as well as zero bulk field solutions with edge fields only and intermediate solutions with zero field at specific sites, valid ford-dimensional arrays. The definite magnetization projected GS's at factorization can be analytically determined and depend only on the exchange anisotropies, exhibiting critical entanglement properties. We also show that some factorization compatible field configurations may result in field-induced frustration and nontrivial behavior at strong fields.Facultad de Ciencias Exacta
Inducing critical phenomena in spin chains through sparse alternating fields
We analyze the phase diagram of the exact ground state (GS) of spin-s chains with ferromagnetic XXZ couplings under n-alternating field configurations, i.e., sparse alternating fields having nodes at n − 1 contiguous sites. It is shown that such systems can exhibit a nontrivial magnetic behavior, which can differ significantly from that of the standard (n = 1) alternating case and enable mechanisms for controlling their magnetic and entanglement properties. The boundary in field space of the fully aligned phase can be determined analytically ∀ n, and shows that it becomes reachable only above a threshold value of the coupling anisotropy Jz/J , which depends on n but is independent of the system size. Below this value, the maximum attainable magnetization becomes much smaller. We then show that the GS can exhibit significant magnetization plateaus, persistent for large systems, at which the magnetization per site m obeys the quantization rule 2n(s − m) = integer, consistent with the Oshikawa, Yamanaka, and Affleck criterion. We also identify the emergence of field-induced spin polymerization, which explains the presence of such plateaus. Entanglement and field-induced frustration effects are also analyzed.Fil: Cerezo de la Roca, Marco Vinicio Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Rossignoli, Raúl Dante. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Canosa, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Lamas, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin
Consistencia en los estilos de madres y padres y estrés manifestado en adolescentes
Este estudio tenía por objetivo examinar si la atribución individual y conjunta del estilo de socialización familiar se relacionaba con las manifestaciones emocionales, fisiológicas y conductuales asociadas al estrés. Ochocientos cincuenta y siete estudiantes de educación secundaria obligatoria, con edades com prendidas entre los 12 y los 16 años, participaron en este estudio. Para identificar los diferentes estilos educativos parentales se realizaron dos análisis de clusters por separado (madres y padres) empleando las puntuaciones otorgadas en diferentes dimensiones (afecto, disciplina inductiva, disciplina rígida y disciplina negligente). Los resultados sugieren que la atribución de un estilo de socialización familiar democrático se relaciona con menores índices de manifestaciones emocionales, fisiológicas y conductuales vinculadas al estrés. Asimismo, la presencia de un padre democrático en la familia parece asociada a la reducción de manifestaciones de estrés cuando se compara con la combinación de cualquier otro patrón incongruente e incluso congruente distinto al democrático. Finalmente, los chicos afirmaron exhibir en mayor grado que las chicas manifestaciones conductuales asociadas al estrés.This study was conducted with the goal of evaluating whether individual and joined attributions of parenting styles (authoritative, permissive, affective-authoritarian and neglectful) was related to emotional, physiological and behavioral manifestations of stress. Eight hundred and fifty seven high school students of compulsory secondary education ranging 12 and 16 years old participated in the study. To identify parenting styles, two separate cluster analyses were conducted on the maternal and paternal parenting variables (caring, inductive discipline, severe discipline and indulgent discipline). Results suggested that authoritative parenting style was linked to lower levels of physiological, emotional and behavioral manifestations of stress. Moreover, the presence of an authoritative parent is linked to stress reduction when compared with any other congruent or incongruent parenting style different from the authoritative one. Finally, boys showed behavioral manifestations of stress in a higher degree than girls
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