37 resultados para Extreme-right
Resumo:
It has been argued that a black hole horizon can support the long-range fields of a Nielsen-Olesen string and that one can think of such a vortex as black hole "hair." In this paper, we examine the properties of an Abelian Higgs vortex in the presence of a charged black hole as we allow the hole to approach extremality. Using both analytical and numerical techniques, we show that the magnetic field lines (as well as the scalar field) of the vortex are completely expelled from the black hole in the extreme limit. This was to be expected, since extreme black holes in Einstein-Maxwell theory are known to exhibit such a "Meissner effect" in general. This would seem to imply that a vortex does not want to be attached to an extreme black hole. We calculate the total energy of the vortex fields in the presence of an extreme black hole. When the hole is small relative to the size of the vortex, it is energetically favored for the hole to remain inside the vortex region, contrary to the intuition that the hole should be expelled. However, as we allow the extreme horizon radius to become very large compared to the radius of the vortex, we do find evidence of an instability. This proves that it is energetically unfavorable for a thin vortex to interact with a large extreme black hole. This would seem to dispel the notion that a black hole can support "long" Abelian Higgs hair in the extreme limit. We show that these considerations do not go through in the near-extreme limit. Finally, we discuss the implications for strings that end at black holes, as in the processes where a string snaps by nucleating black holes.
Resumo:
It has been claimed that extreme black holes exhibit a phenomenon of flux expulsion for Abelian Higgs vortices, irrespective of the relative width of the vortex to the black hole. Recent work by two of the authors showed a subtlety in the treatment of the event horizon, which cast doubt on this claim. We analyze in detail the vortexextreme black hole system, showing that, while flux expulsion can occur, it does not do so in all cases. We give analytic proofs for both expulsion and penetration of flux, in each case deriving a bound for that behavior. We also present extensive numerical work backing up, and refining, these claims, and showing in detail how a vortex can end on a black hole in all situations. We also calculate the back reaction of the vortex on the geometry, and comment on the more general vortexblack hole system.
Resumo:
It has been argued that a black hole horizon can support the long range fields of a Nielsen-Olesen string, and that one can think of such a vortex as black hole hair. We show that the fields inside the vortex are completely expelled from a charged black hole in the extreme limit (but not in the near extreme limit). This would seem to imply that a vortex cannot be attached to an extreme black hole. Furthermore, we provide evidence that it is energetically unfavorable for a thin vortex to interact with a large extreme black hole. This dispels the notion that a black hole can support long Abelian Higgs hair in the extreme limit.
Resumo:
We apply the theory of continuous time random walks (CTRWs) to study some aspects involving extreme events in financial time series. We focus our attention on the mean exit time (MET). We derive a general equation for this average and compare it with empirical results coming from high-frequency data of the U.S. dollar and Deutsche mark futures market. The empirical MET follows a quadratic law in the return length interval which is consistent with the CTRW formalism.
Resumo:
Extreme times techniques, generally applied to nonequilibrium statistical mechanical processes, are also useful for a better understanding of financial markets. We present a detailed study on the mean first-passage time for the volatility of return time series. The empirical results extracted from daily data of major indices seem to follow the same law regardless of the kind of index thus suggesting an universal pattern. The empirical mean first-passage time to a certain level L is fairly different from that of the Wiener process showing a dissimilar behavior depending on whether L is higher or lower than the average volatility. All of this indicates a more complex dynamics in which a reverting force drives volatility toward its mean value. We thus present the mean first-passage time expressions of the most common stochastic volatility models whose approach is comparable to the random diffusion description. We discuss asymptotic approximations of these models and confront them to empirical results with a good agreement with the exponential Ornstein-Uhlenbeck model.
Resumo:
[spa] El principal objetivo de este artículo se centra en analizar los orígenes del Estado de Bienestar en España a partir del marco teórico elaborado por Peter Lindert. Con este fin, se ofrece un análisis econométrico de los factores que determinaron la evolución del gasto social público en este país entre 1880 y 1960. Utilizando nueva evidencia cuantitativa, se construyó un panel de datos por quinquenios con el porcentaje de gasto social respecto al PIB desagregado en tres partidas: sanidad, seguridad social y beneficencia. El análisis permite insertar el caso español en el debate internacional y los resultados revelan interesantes singularidades de este país.
Resumo:
Although assignment games are hardly ever convex, in this paper a characterization of their set or extreme points of the core is provided, which is also valid for the class of convex games. For each ordering in the player set, a payoff vector is defined where each player receives his marginal contribution to a certain reduced game played by his predecessors. We prove that the whole set of reduced marginal worth vectors, which for convex games coincide with the usual marginal worth vectors, is the set of extreme points of the core of the assignment game
Resumo:
Testing weather or not data belongs could been generated by a family of extreme value copulas is difficult. We generalize a test and we prove that it can be applied whatever the alternative hypothesis. We also study the effect of using different extreme value copulas in the context of risk estimation. To measure the risk we use a quantile. Our results have motivated by a bivariate sample of losses from a real database of auto insurance claims. Methods are implemented in R.
Resumo:
The methodology of the ager Tarraconensis project also included geophysical surveys aiming to distinguish different categories of rural settlements. Two geophysical techniques (resistivity and magnetometry) were combined to reveal traces of unearth structures from a selection of sites identified from the field survey. Results of geophysical surveys of these seven sites as well as conclusions obtained from this approach are discussed here.
Resumo:
Este trabajo se enfoca en la traslación de los marcadores pragmáticos en las traducciones rusas de "Right Ho, Jeeves" de P.G. Wodehouse. Aún siendo vacíos semánticamente y opcionales gramaticalmente, estas unidades son indispensables desde el punto de vista pragmático ya que desempeñan muchas funciones en los ámbitos textual e interpersonal. Como son multifuncionales y polisémicos, las equivalencias dadas en los diccionarios bilingües no alcanzan todas las situaciones comunicativas en que se utilizan. Son buenos indicadores que permiten observar la transferencia tanto de las peculiaridades discursivas como del retrato de la relación interpersonal de los protagonistas, dos componentes clave del humor de la novela analizada. El grado de conservación de la carga pragmática y del nivel de formalidad repecute en la construcción del caracter del personaje y en este caso en la representación de la pareja del señor y su criado — un constructo literario que varía según la cultura.
Resumo:
Este trabajo se enfoca en la traslación de los marcadores pragmáticos en las traducciones rusas de "Right Ho, Jeeves" de P.G. Wodehouse. Aún siendo vacíos semánticamente y opcionales gramaticalmente, estas unidades son indispensables desde el punto de vista pragmático ya que desempeñan muchas funciones en los ámbitos textual e interpersonal. Como son multifuncionales y polisémicos, las equivalencias dadas en los diccionarios bilingües no alcanzan todas las situaciones comunicativas en que se utilizan. Son buenos indicadores que permiten observar la transferencia tanto de las peculiaridades discursivas como del retrato de la relación interpersonal de los protagonistas, dos componentes clave del humor de la novela analizada. El grado de conservación de la carga pragmática y del nivel de formalidad repecute en la construcción del caracter del personaje y en este caso en la representación de la pareja del señor y su criado — un constructo literario que varía según la cultura.
Resumo:
Objectives: To evaluate the correct diagnosis in unselected patients presenting withsuspected acute appendicitis in the Emergency Department in Hospital Trueta. To evaluate the different scenarios to achieve the correct diagnosis in patients with suspected acute appendicitis estimated by clinical evaluation without imaging, US only, CT only or US in all patients followed by CT after a non-diagnostic US.Design: Cross-sectional study conducted between April 2014 and March 2015.Settings: Medium-sized teaching hospital in Girona.Participants: Consecutive adult patients, 14 years old or older, with clinically suspectedacute appendicitis evaluated at the emergency department.Main outcome: Correct diagnosis of acute appendicitis
Resumo:
The effect of age at the first mating and herd size were evaluated in the reference Spanish Databank (BDporc) of 37 698 sows born between 1991 and 1995 and with individual lifetime records. The data included dates of births at entrance and culling, first mating, repetitive mating and conception, first farrowing and weaning records. Individual records were validated before the analysis by screening them through a tolerance “filter” in order to eliminate the extreme values from the analysis. The total database of the sows was classified in 7 classes according to age at the first mating (< 210, 210–220, 221–230, 231–240, 241–250, 251–270, and > 270 days) and in 6 classes of herd size (< 200, 200–300, 301–400, 401–600, 601–800, and > 800 sows). The total number of litters and number of weaned piglets obtained from each sow during the lifetime production were significantly (P < 0.05) greater for gilts between 221 and 240 d of age at the first mating. There was a significant (P < 0.001) effect of the herd size on the reproductive performance of the sow, and the best performance was obtained with herds with 401 to 600 sows compared to < 200 or > 800 sow-herds. Furthermore, a significant (P < 0.001) interaction between age at the first mating and herd size was detected and can be associated with a particular pattern for the herd size class 401–600 sows with the best performances obtained for the sows first mated at less than 200 days. For the other herd sizes, the results indicated that sows mated for the first time at the right age, 221–240 days, are more productive, both in the number and size of the parities throughout lifetime production.
Resumo:
In the classical theorems of extreme value theory the limits of suitably rescaled maxima of sequences of independent, identically distributed random variables are studied. The vast majority of the literature on the subject deals with affine normalization. We argue that more general normalizations are natural from a mathematical and physical point of view and work them out. The problem is approached using the language of renormalization-group transformations in the space of probability densities. The limit distributions are fixed points of the transformation and the study of its differential around them allows a local analysis of the domains of attraction and the computation of finite-size corrections.