Onsager-Manning-Oosawa condensation phenomenon and the effect of salt

Making use of results pertaining to Painleve III type equations, we revisit the celebrated Onsager-Manning-Oosawa condensation phenomenon for charged stiff linear polymers, in the mean-field approximation with salt. We obtain analytically the associated critical line charge density, and show that it is severely affected by finite salt effects, whereas previous results focused on the no salt limit. In addition, we obtain explicit expressions for the condensate thickness and the electric potential. The case of asymmetric electrolytes is also briefly addressed.Comment: to appear in Phys. Rev. Let

Exact asymptotic expansions for the cylindrical Poisson-Boltzmann equation

The mathematical theory of integrable Painleve/Toda type systems sheds new light on the behavior of solutions to the Poisson-Boltzmann equation for the potential due to a long rod-like macroion. We investigate here the case of symmetric electrolytes together with that of 1:2 and 2:1 salts. Short and large scale features are analyzed, with a particular emphasis on the low salinity regime. Analytical expansions are derived for several quantities relevant for polyelectrolytes theory, such as the Manning radius. In addition, accurate and practical expressions are worked out for the electrostatic potential, which improve upon previous work and cover the full range of radial distances

Expanded Vandermonde powers and sum rules for the two-dimensional one-component plasma

The two-dimensional one-component plasma (2dOCP) is a system of $N$ mobile particles of the same charge $q$ on a surface with a neutralising background. The Boltzmann factor of the 2dOCP at temperature $T$ can be expressed as a Vandermonde determinant to the power $\Gamma=q^{2}/(k_B T)$. Recent advances in the theory of symmetric and anti-symmetric Jack polymonials provide an efficient way to expand this power of the Vandermonde in their monomial basis, allowing the computation of several thermodynamic and structural properties of the 2dOCP for $N$ values up to 14 and $\Gamma$ equal to 4, 6 and 8. In this work, we explore two applications of this formalism to study the moments of the pair correlation function of the 2dOCP on a sphere, and the distribution of radial linear statistics of the 2dOCP in the plane

Two-dimensional one-component plasma on a Flamm's paraboloid

We study the classical non-relativistic two-dimensional one-component plasma at Coulomb coupling Gamma=2 on the Riemannian surface known as Flamm's paraboloid which is obtained from the spatial part of the Schwarzschild metric. At this special value of the coupling constant, the statistical mechanics of the system are exactly solvable analytically. The Helmholtz free energy asymptotic expansion for the large system has been found. The density of the plasma, in the thermodynamic limit, has been carefully studied in various situations

Identifying clusters of anomalous payments in the salvadorian payment system

We develop an unsupervised methodology to group payments and identify possible anomalies. With our methodology, we identify clusters based on a set of network features, using transactional (unlabeled) information from a systemically important payment system of El Salvador. We first preprocess network features, such as degree and strength, through a principal components analysis we reduce the dimensionality of the newly defined data, then we place the main variables into clustering algorithms (k-means and DBSCAN) to analyze anomalous payments. We then analyze, these clusters using random forest to obtain the main network feature. Our results suggest that the proposed methodology works very well to detect anomalous payments, and it is very important to study the case of El Salvador, because of the recent restructuring of the Massive Payment System in El Salvador (promoted by the Transfer365 project), because the authorities want to increase financial inclusion. This change will make the SPM available to the public, to diversify services and incorporate more participants because, historically, it has operated with only three active participants. We expected that Transfer365 will interconnect the LBTR participants' systems with their banking core, the systems of the Ministry of Finance, and other authorized participants to channel large payment flows. Then, identifying possible anomalies through methodology will enhance risk monitoring and management by payment systems overseers

El efecto del entrenamiento propioceptivo en la recuperación funcional en artrosis de la base del pulgar. A propósito de un caso

El complejo ligamentario dorsal del pulgar es la estructura con mayor concentración de mecanorreceptores, especialmente corpúsculos de Ruffini. Todas las aferencias que se originan en los mecanorreceptores del pulgar constituyen su propiocepción, que es esencial para un control sensoriomotor bien adaptado (Suetterlin y Sayer,2014). Las enfermedades que tienen implicancia sobre el pulgar, como la osteoartritis (OA) carpo-metacarpiana (CMC), impactan en su función, y consecuentemente en el desempeño ocupacional de las personas. Una mujer de 50 años con OA CMC fue derivada para tratamiento conservador de Terapia Ocupacional (T.O), diagnosticada cuatro meses antes, el diagnóstico médico explicitaba estadio II de Eaton et al.  en mano derecha, dominante. Trabajó 28 años como empleada administrativa y actualmente es ama de casa. En la evaluación inicial refirió preocupación y frustración al realizar sus actividades diarias, acusó dolor y presentó deterioro en la función manual. Se aplicó un tratamiento conservador tradicional combinado con ejercicios propioceptivos durante 3 meses. Las medidas de resultado indicaron una mejora en la propiocepción del pulgar y una mejora significativa en el desempeño ocupacional y el dolor. Se incluyeron el Joint Position Sense Test, la Medida Canadiense de Rendimiento Ocupacional, la sub Escala Funcional del Australian Canadian Osteoarthritis Hand Index y la Escala Visual Analógica. Seguimientos: 1 mes y 3 meses. El tratamiento mejoró significativamente el desempeño ocupacional y sensibilidad propioceptiva de un paciente con deterioro funcional relacionado con OA CMC en su mano dominante