47,511 research outputs found

    Study of a model for the distribution of wealth

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    An equation for the evolution of the distribution of wealth in a population of economic agents making binary transactions with a constant total amount of "money" has recently been proposed by one of us (RLR). This equation takes the form of an iterated nonlinear map of the distribution of wealth. The equilibrium distribution is known and takes a rather simple form. If this distribution is such that, at some time, the higher momenta of the distribution exist, one can find exactly their law of evolution. A seemingly simple extension of the laws of exchange yields also explicit iteration formulae for the higher momenta, but with a major difference with the original iteration because high order momenta grow indefinitely. This provides a quantitative model where the spreading of wealth, namely the difference between the rich and the poor, tends to increase with time.Comment: 12 pages, 2 figure

    One-dimensional relativistic dissipative system with constant force and its quantization

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    For a relativistic particle under a constant force and a linear velocity dissipation force, a constant of motion is found. Problems are shown for getting the Hamiltoninan of this system. Thus, the quantization of this system is carried out through the constant of motion and using the quantization of the velocity variable. The dissipative relativistic quantum bouncer is outlined within this quantization approach.Comment: 11 pages, no figure

    f(R) brane cosmology

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    Despite the nice features of the Dvali, Gabadadze and Porrati (DGP) model to explain the late-time acceleration of the universe, it suffers from some theoretical problems like the ghost issue. We present a way to self-accelerate the normal DGP branch, which is known to be free of the ghost problem, by means of an f(R) term on the brane action. We obtain the de Sitter self-accelerating solutions of the model and study their stability under homogeneous perturbations.Comment: 4 pages, 2 figures. Contribution to the proceedings of Spanish Relativity Meeting 2009, Bilbao, Spain, 7-11 September 200

    Number and Amplitude of Limit Cycles emerging from {\it Topologically Equivalent} Perturbed Centers

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    We consider three examples of weekly perturbed centers which do not have {\it geometrical equivalence}: a linear center, a degenerate center and a non-hamiltonian center. In each case the number and amplitude of the limit cycles emerging from the period annulus are calculated following the same strategy: we reduce of all of them to locally equivalent perturbed integrable systems of the form: dH(x,y)+ϵ(f(x,y)dyg(x,y)dx)=0dH(x,y)+\epsilon(f(x,y)dy-g(x,y)dx)=0, with H(x,y)=1/2(x2+y2)H(x,y)={1/2}(x^2+y^2). This reduction allows us to find the Melnikov function, M(h)=H=hfdygdxM(h)=\int_{H=h}fdy-gdx, associated to each particular problem. We obtain the information on the bifurcation curves of the limit cycles by solving explicitly the equation M(h)=0M(h)=0 in each case.Comment: 17 pages, 0 figure

    Detecting synchronization in spatially extended discrete systems by complexity measurements

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    The synchronization of two stochastically coupled one-dimensional cellular automata (CA) is analyzed. It is shown that the transition to synchronization is characterized by a dramatic increase of the statistical complexity of the patterns generated by the difference automaton. This singular behavior is verified to be present in several CA rules displaying complex behavior.Comment: 4 pages, 2 figures; you can also visit http://add.unizar.es/public/100_16613/index.htm

    ¿Modifican el PSA los licopenos de la dieta y exógenos?

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    El objetivo del presente artículo es describir la historia alimentaria y la composición corporal de pacientes con alto riesgo de padecer cáncer de próstata (CAP) y observar la influencia de la suplementación con licopeno sobre el PSA de la misma población.Fil: López Laur, José Daniel. Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: López Fontana, C.. Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: López Fontana, G.. Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: López Fontana, R.. Universidad Nacional de Cuyo. Facultad de Ciencias Médica

    Banking industry evolution along the Texas-Mexico border

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    Maquiladora ; Income ; Remittances ; Emerging markets ; Federal Reserve Bank of Dallas ; Debit cards

    Genetic study in patients operated dentally and anesthetized with articaine-epinephrine

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    Aims: In this study we wanted to figure out if there was a correlation between OPRM1 N40D, TRPV1 I316M, TRPV1 I585V, NOS3 −786T>C and IL6 −174C>G polymorphisms and the response to locally applied articaine-epinephrine anesthetic. Methods: In this observational study, 114 oral cell samples of patients anesthetized with articaine-epinephrine (54 from men 60 from women), were collected from dental centers in Madrid (Spain). High molecular weight DNA was obtained from oral mucosa cells. The analysis of OPRM1 N40D (rs1799971), TRPV1 I316M (rs222747), TRPV1 I585V (rs8065080) and IL6 −174C>G polymorphism was performed through real-time PCR allelic discrimination using TaqMan probes. Polymorphism NOS3 −786T> C (rs2070744) was analyzed using RFLP-PCR. Results: The studied polymorphisms are involved neither in the response to the anesthetic, nor in the intensity of perceived dental pain. However, in a subset of female patients we found that TRPV1 I316M was associated with a delayed onset of anesthesia. Conclusions: There is no association among these polymorphisms and the time elapsed between the application of the anesthetic and the onset of its effect
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