Embarazo adolescente: Diversidad de síntomas de un mismo diagnóstico / Teenage pregnancy: Diversity of symptoms of the same diagnosis

Introducción: En la Argentina, hay 754.600 nacimientos por año, de los cuales el 15% proviene de madres adolescentes de entre 15 a 19 años. Este porcentaje varía en las diferentes provincias, siendo mayor en el Noreste y Noroeste argentino. El 65.5% de ellas no usaba ningún método anticonceptivo al momento de la concepción, muchas de ellas por desconocimiento sobre salud reproductiva. La alta frecuencia de embarazos en la población adolescente, muchos de ellos no planeados, aumenta el riesgo de exposición a un aborto inseguro, abandono escolar y de limitaciones en el acceso al mercado laboral, condicionando así las perspectivas de desarrollo personal. Es evidente que la diversidad de manifestaciones clínicas de esta entidad hace que ante la consulta del adolescente no siempre se lo tenga presente como posible diagnóstico diferencial en primera instancia. Considerar el embarazo a tiempo optimizaría la atención al brindar información a la paciente y al realizar la derivación a un centro especializado para su seguimiento. Asimismo también se evitaría la utilización de métodos diagnósticos o terapéuticos que resulten nocivos para el producto de la gestación. Objetivos: Describir los motivos de consulta realizados por pacientes adolescentes menores de 19 años, en el Hospital Garrahan durante el período comprendido entre 2012 y 2016, que concluyeron con el diagnóstico de embarazo. Describir el número de consultas, y exámenes complementarios solicitados hasta que se arribó al diagnóstico. Metodología: estudio retrospectivo, descriptivo observacional, a través del análisis de las historias clínicas (HC) y base de datos del laboratorio de todas las pacientes femeninas menores de 19 años, que hayan consultado en el periodo comprendido entre 2012 a 2016. Resultado: Se obtuvo un total de 46 pacientes adolescentes con diagnóstico de embarazo. Si bien el síntoma más frecuente fue la alteración del ciclo menstrual, sólo en el 50% fue lo que motivó la consulta. En el 74% de los casos el diagnóstico se realizó en la primera atención. En el 33% de las pacientes no se registró en la HC el uso de MAC (Métodos Anti Conceptivos). En los casos que se interrogó acerca del uso de MAC, sólo el 55% lo hacía en forma correcta. Conclusión: El diagnóstico de embarazo debe considerarse frente a la consulta de pacientes adolescentes. Es necesario pesquisar la existencia de alteraciones en el ciclo menstrual y el uso de MAC en esta población (AU)

In Argentina, there are 754,600 births yearly, of which 15% are to adolescent mothers between 15 and 19 years of age. This percentage varies according to the different provinces, and is higher in the north-east and north-west of the country. Of the mothers, 65.5% did not use any contraceptive method at the moment of conception, in many of them due to lack of knowledge of reproductive health. The high rate of teenage pregnancies, many of them unplanned, increases the risk of exposure to unsafe abortions, school drop-out, limitation to access to the labor market thereby reducing perspectives of personal development. Clearly, the variability of clinical manifestations associated with this entity, in an adolescent pregnancy is not always considered as an early differential diagnosis. Early awareness of pregnancy would improve care by providing information to the patient and referral to a specialized center for follow-up. Additionally, the use of diagnostic or therapeutic methods that are harmful for the fetus are avoided. Objectives: To describe the reasons for consultation of teenage patients under 19 years of age at Garrahan Hospital between 2012 and 2016, in whom finally the diagnosis was pregnancy and to describe the number of consultation and complementary exams previous to the diagnosis. Methodology: A retrospective, descriptive, observational study was conducted through the analysis of clinical charts (CC) and laboratory data base of all female patients younger than 19 years of age that consulted between 2012 and 2016. Results: 46 teenage patients with the diagnosis of pregnancy were identified. Although the most frequent symptom was alteration of the menstrual cycle, this was the reason for consultation in only 50%. In 74% of the cases the diagnosis was made in the first visit. In 33% of the patients the use of methods of contraception (MOC) was not recorded in the CC. When the patient was asked about the use of MOC, only 55% used them correctly. Conclusion: The diagnosis of pregnancy should be considered in teenage patients. Screening for alterations in the menstruation and the use of MOC is necessary in this population (AU)

Constructing criteria to diagnose the likelihood of extreme events in the case of the electric power grid.

A set of new criteria for the diagnosis of the possible occurrence of a large blackout are constructed, using the output from a model for the dynamics of the electric power grid (the OPA model). The approach used is to look for maximum values of the Transfer Entropy between time series of the system variables and the time series of large blackouts. The best criterion is found by looking at the number of overloaded lines at the beginning of the day.

Does size matter?

Failures of the complex infrastructures society depends on having enormous human and economic cost that poses the question: Are there ways to optimize these systems to reduce the risks of failure? A dynamic model of one such system, the power transmission grid, is used to investigate the risk from failure as a function of the system size. It is found that there appears to be optimal sizes for such networks where the risk of failure is balanced by the benefit given by the size.

[Bacteriological analysis in the management of conjunctivitis. Comparison of antibiotic resistance between 1982 and 2008]. / Análisis bacteriológicos en el tratamiento de las conjuntivitis. Comparación de la resistencia a antibióticos entre 1982 y 2008.

OBJECTIVE: To demonstrate the need for bacteriological analysis for the rational treatment of infections of the corneal surface, including conjunctivitis. METHODS: The results of 1,970 consecutive bacteriological analysis obtained from 2001 to 2008 in patients with ocular hyperemia and discharge were analysed and compared with a similar study done in 1982 in the same geographical area. RESULTS: Bacterial growth was obtained in 1,044 cases (53%). The most frequent bacteria were Staphylococci spp. (56.6%), followed by Streptococci spp. (21.4%), Haemophili spp. (12.1%), and other gram-negative bacteria (9.9%). No antibiotic was effective against all the bacteria isolated. The frequency of resistant bacteria against neomycin, tobramycin, erythromycin and gentamicin was significantly increased with respect to the study of 1982. CONCLUSIONS: Bacteriological analysis of conjunctival specimens are necessary to ensure the choice of an effective antibiotic against bacteria of the ocular surface when the initial treatment fails.

Análisis bacteriológicos en el tratamiento de las conjuntivitis. Comparación de la resistencia a antibióticos entre 1982 y 2008 / Bacteriological analysis in the management of conjunctivitis. Comparison of antibiotic resistance between 1982 and 2008

Objetivo: Mostrar la necesidad de análisis bacteriológicos para un tratamiento racional de las infecciones de la superficie ocular, incluyendo las conjuntivitis. Métodos: Los resultados de 1.970 análisis bacteriológicos consecutivos, obtenidos desde 2001 a 2008, en pacientes con hiperemia conjuntival y secreción fueron contados y comparados con un estudio similar realizado en 1982 en la misma área geográfica. Resultados: Se obtuvo crecimiento bacteriano en 1.044 casos (53%). Las bacterias más frecuentes fueron Staphylococci spp. (56,6%), seguidos de Streptococci spp. (21,4%), Haemophili spp. (12,1%) y otras bacterias gram-negativas (9,9%). Ningún antibiótico fue eficaz frente a todas las bacterias aisladas. La frecuencia de bacterias resistentes a la neomicina, tobramicina, eritromicina y gentamicina estaba significativamente aumentada con respecto al estudio de 1982. Conclusiones: Los análisis bacteriológicos de las muestras obtenidas de la conjuntiva son necesarios para asegurar la elección de un antibiótico efectivo frente a las bacterias de la superficie ocular cuando fracasa el tratamiento inicial(AU)

Objective: To demonstrate the need for bacteriological analysis for the rational treatment of infections of the corneal surface, including conjunctivitis. Methods: The results of 1,970 consecutive bacteriological analysis obtained from 2001 to 2008 in patients with ocular hyperemia and discharge were analysed and compared with a similar study done in 1982 in the same geographical area. Results: Bacterial growth was obtained in 1,044 cases (53%). The most frequent bacteria were Staphylococci spp. (56.6%), followed by Streptococci spp. (21.4%), Haemophili spp. (12.1%), and other gram-negative bacteria (9.9%). No antibiotic was effective against all the bacteria isolated. The frequency of resistant bacteria against neomycin, tobramycin, erythromycin and gentamicin was significantly increased with respect to the study of 1982. Conclusions: Bacteriological analysis of conjunctival specimens are necessary to ensure the choice of an effective antibiotic against bacteria of the ocular surface when the initial treatment fails(AU)

Dynamical coupling between gradients and transport in fusion plasmas.

The dynamical coupling between density gradients and particle transport has been investigated using similar experimental tools in the plasma boundary of different tokamak (JET, ISTTOK) and stellarator (TJ-II) devices, showing that the size of turbulent events is minimum in the proximity of the most probable density gradient. Experimental results were found to be consistent with results from two very different models of plasma turbulence and transport. The present findings, common to several plasma devices, suggest the importance of self-regulation mechanisms between plasma transport and gradients in fusion devices.

Topological characterization of the transition from laminar regime to fully developed turbulence in the resistive pressure-gradient-driven turbulence model.

For the resistive pressure-gradient-driven turbulence model, the transition from laminar regime to fully developed turbulence is not simple and goes through several phases. For low values of the plasma parameter beta, a single quasicoherent structure forms. As beta increases, several of these structures may emerge and in turn take the dominant role. Finally, at high beta, fully developed turbulence with a broad spectrum is established. A suitable characterization of this transition can be given in terms of topological properties of the flow. Here, we analyze these properties that provide an understanding of the turbulence-induced transport and give a measure of the breaking of the homogeneity of the turbulence. To this end, an approach is developed that allows discriminating between topological properties of plasma turbulence flows that are relevant to the transport dynamics and the ones that are not. This is done using computational homology tools and leads to a faster convergence of numerical results for a fixed level of resolution than previously presented in Phys. Rev. E 78, 066402 (2008).

The impact of risk-averse operation on the likelihood of extreme events in a simple model of infrastructure.

A simple dynamic model of agent operation of an infrastructure system is presented. This system evolves over a long time scale by a daily increase in consumer demand that raises the overall load on the system and an engineering response to failures that involves upgrading of the components. The system is controlled by adjusting the upgrading rate of the components and the replacement time of the components. Two agents operate the system. Their behavior is characterized by their risk-averse and risk-taking attitudes while operating the system, their response to large events, and the effect of learning time on adapting to new conditions. A risk-averse operation causes a reduction in the frequency of failures and in the number of failures per unit time. However, risk aversion brings an increase in the probability of extreme events.

Nature of transport across sheared zonal flows in electrostatic ion-temperature-gradient gyrokinetic plasma turbulence.

It is shown that the usual picture for the suppression of turbulent transport across a stable sheared flow based on a reduction of diffusive transport coefficients is, by itself, incomplete. By means of toroidal gyrokinetic simulations of electrostatic, collisionless ion-temperature-gradient turbulence, it is found that the nature of the transport is altered fundamentally, changing from diffusive to anticorrelated and subdiffusive. Additionally, whenever the flows are self-consistently driven by turbulence, the transport gains an additional non-Gaussian character. These results suggest that a description of transport across sheared flows using effective diffusivities is oversimplified.

Characterization of nondiffusive transport in plasma turbulence via a novel Lagrangian method.

A novel method to probe and characterize the nature of the transport of passive scalars carried out by a turbulent flow is introduced. It requires the determination of two exponents which encapsulate the statistical and correlation properties of the component of interest of the Lagrangian velocities of the flow. Numerical simulations of a magnetically confined, near-critical turbulent plasma, known to exhibit superdiffusive radial transport, are used to illustrate the method. It is shown that the method can easily detect the change in the dynamics of the radial transport that takes place after adding to the simulations a (subdominant) diffusive channel of tunable strength.

Evidence of long-distance correlation of fluctuations during edge transitions to improved-confinement regimes in the TJ-II stellarator.

Long-distance coupling between edge parameters' fluctuations has been investigated in the TJ-II stellarator. Results show long-range correlations in potential fluctuations, which are amplified by the development of radial electric fields during transitions to improved-confinement regimes, whereas there is no correlation between ion saturation current signals. These experimental findings suggest the importance of long-range correlations as a new fingerprint of the plasma behavior during the development of edge shear flows and the key role of electric fields to amplify them.

Topological characterization of flow structures in resistive pressure-gradient-driven turbulence.

Visualization of turbulent flows is a powerful tool to help understand the turbulence dynamics and induced transport. However, it does not provide a quantitative description of the observed structures. In this paper, an approach to characterize quantitatively the topology of the flows is given. The technique, which can be applied to any type of turbulence dynamics, is illustrated through the example of resistive ballooning instabilities.

Fractional generalization of Fick's law: a microscopic approach.

In the study of transport in inhomogeneous systems it is common to construct transport equations invoking the inhomogeneous Fick law. The validity of this approach requires that at least two ingredients be present in the system. First, finite characteristic length and time scales associated with the dominant transport process must exist. Second, the transport mechanism must satisfy a microscopic symmetry: global reversibility. Global reversibility is often satisfied in nature. However, many complex systems exhibit a lack of finite characteristic scales. In this Letter we show how to construct a generalization of the inhomogeneous Fick law that does not require the existence of characteristic scales while still satisfying global reversibility.

Renormalization of tracer turbulence leading to fractional differential equations.

For many years quasilinear renormalization has been applied to numerous problems in turbulent transport. This scheme relies on the localization hypothesis to derive a linear transport equation from a simplified stochastic description of the underlying microscopic dynamics. However, use of the localization hypothesis narrows the range of transport behaviors that can be captured by the renormalized equations. In this paper, we construct a renormalization procedure that manages to avoid the localization hypothesis completely and produces renormalized transport equations, expressed in terms of fractional differential operators, that exhibit much more of the transport phenomenology observed in nature. This technique provides a first step toward establishing a rigorous link between the microscopic physics of turbulence and the fractional transport models proposed phenomenologically for a wide variety of turbulent systems such as neutral fluids or plasmas.

Topological instability along invariant surfaces and pseudochaotic transport.

The paper describes the complex topological structure of invariant surfaces that appears in a quasi-stationary regime of the tokamak plasma, and it considers in detail anomalous transport of particles along the invariant surfaces (isosurfaces) that have topological genus greater than 1. Such dynamics is pseudochaotic; i.e. it has a zero Lyapunov exponent. Simulations discover such surfaces in confined plasmas under a fairly low ratio of pressure to the magnetic field energy (beta). The isosurfaces correspond to quasi-coherent structures called "streamers" and the streamers are connected by filaments. We study distribution of time of particle separation, Poincaré; recurrences of trajectories, and first time arrival to the system's edge. A model of a multibar-in-square billiard, introduced by Carreras et al. [Chaos 13, 1175 (2003)] is studied with renormalization group method to obtain a distribution of the first time of particles arrival to the edge as a function of the number of bars, which appears to be power-like. The characteristic exponent of this distribution is discussed with respect to its dependence on the number of filaments that connect adjacent streamers.

Nondiffusive transport in plasma turbulence: a fractional diffusion approach.

Numerical evidence of nondiffusive transport in three-dimensional, resistive pressure-gradient-driven plasma turbulence is presented. It is shown that the probability density function (pdf) of tracer particles' radial displacements is strongly non-Gaussian and exhibits algebraic decaying tails. To model these results we propose a macroscopic transport model for the pdf based on the use of fractional derivatives in space and time that incorporate in a unified way space-time nonlocality (non-Fickian transport), non-Gaussianity, and nondiffusive scaling. The fractional diffusion model reproduces the shape and space-time scaling of the non-Gaussian pdf of turbulent transport calculations. The model also reproduces the observed superdiffusive scaling.

Fluid limit of nonintegrable continuous-time random walks in terms of fractional differential equations.

The fluid limit of a recently introduced family of nonintegrable (nonlinear) continuous-time random walks is derived in terms of fractional differential equations. In this limit, it is shown that the formalism allows for the modeling of the interaction between multiple transport mechanisms with not only disparate spatial scales but also different temporal scales. For this reason, the resulting fluid equations may find application in the study of a large number of nonlinear multiscale transport problems, ranging from the study of self-organized criticality to the modeling of turbulent transport in fluids and plasmas.

Complex dynamics of blackouts in power transmission systems.

In order to study the complex global dynamics of a series of blackouts in power transmission systems a dynamical model of such a system has been developed. This model includes a simple representation of the dynamical evolution by incorporating the growth of power demand, the engineering response to system failures, and the upgrade of generator capacity. Two types of blackouts have been identified, each having different dynamical properties. One type of blackout involves the loss of load due to transmission lines reaching their load limits but no line outages. The second type of blackout is associated with multiple line outages. The dominance of one type of blackout over the other depends on operational conditions and the proximity of the system to one of its two critical points. The model displays characteristics such as a probability distribution of blackout sizes with power tails similar to that observed in real blackout data from North America.

Topological instability along filamented invariant surfaces.

In dynamical systems with a zero Lyapunov exponent, weak mixing can be governed by a specific topological structure of some surfaces that are invariant with respect to particle dynamics. In particular, when the genus of the invariant surfaces is more than one, they may have weak mixing and the corresponding fractional kinetics. This possibility is demonstrated by using a typical example from plasma physics, a three-dimensional resistive pressure-gradient-driven turbulence model. In a toroidal geometry and with a low-pressure gradient, this model shows the emergence of quasicoherent structures. In this situation, the isosurfaces of the velocity stream function have a web structure with filamentary surfaces emerging from the outer region of the torus and covering the inner region. The filamentary surfaces can result in stochastic jets of particles that cause a "topological instability." In such a situation, particle transport along the surfaces is of the anomalous superdiffusion type.