Abstract The present work aims to study the nonlinear behavior of reinforced concrete structures via Refined Plastic Hinge Method (RPHM). Pseudo-springs are used at the finite element ends, where the gradual loss of stiffness is determined by the combination of the normal force and bending moment (NM) in the cross section. The limiting of the uncracked, elastic and plastic regimes is done in the NM diagram. The concrete cracking is explicitly simulated with two approaches to calculate the effective moment of inertia of the cross section. The displacement-based formulation is referenced to the co-rotational system and coupled with continuation strategies to allow to overcome the possible critical points in the equilibrium paths. For validation of the numerical simulations, the results found with the proposed formulation are confronted with experimental and numerical data present in literature.

Abstract Objective: To analyze performance and pacing in 200 m butterfly among the semifinalists in 15th FINA World Championship. Methods: Data were obtained from FINA website. Thirty two semifinals performances were divided in four groups: eight male classified (G1M), eight male unclassified (G2M), eight female classified (G1F), and eight female unclassified (G2F). Swimming velocity for each 50 m partial was estimated by the quotient between distance and time. Coefficients of variation of the four 50 m partials were compared among groups (ANOVA). Effects sizes were identified by the Cohen's d. Total time (performance) was correlated with each 50 m partial time (Pearson's r). Results: Coefficients of variation were lower for the groups with best performance in both sexes (G1F and G1M) and in females. The third partial presented the larger correlation with overall performance. Average swimming velocity decreased along the event. Conclusion: The best pacing is to maintain swimming velocity constant within each 50 m over the 200 m and the training should be directed to the conditional improvement of this split (150‐200 m).

Resumo Objetivo: Analisar o desempenho e o pacing de prova dos semifinalistas da prova de 200 m nado borboleta do 15.° Campeonato Mundial de Natação da Federação Internacional de Natação (FINA). Método: Os dados foram obtidos da página eletrônica da FINA. Os 32 tempos da etapa semifinal, masculina e feminina, foram divididos em 4 grupos: 8 homens classificados para a final (G1M), 8 homens não classificados (G2M), 8 mulheres classificadas para a final (G1F) e as 8 mulheres não classificadas (G2F). A velocidade de nado, para cada parcial de 50 m, foi estimada pelo quociente entre 50 m e o respectivo tempo. Foram calculados os coeficientes de variação de tempo das 4 parciais de 50 m e comparados entre os grupos (ANOVA). Tamanho de efeito foi verificado com d de Cohen. Correlacionou‐se o desempenho (tempo total) com o tempo de cada parcial de 50 m (r de Pearson). Resultados: O coeficiente de variação para as parciais de 50 m foi menor nos grupos dos finalistas de ambos os sexos (G1M e G1F) e menor para as mulheres. A terceira parcial de 50 m apresentou maior correlação com o desempenho final em ambos os sexos. A velocidade média caiu ao longo da prova em ambos os grupos. Conclusão: O pacing para o melhor desempenho na prova é evitar variações de tempo ao longo dos 200 m nado borboleta e os treinamentos devem ser direcionados ao aprimoramento condicionante dessa parcial (150‐200 m).

Resumen Objetivo: Analizar el desempeño y pacing durante la prueba de semifinalistas de 200 m mariposa del 15.° Campeonato Mundial de Natación de la Federación Internacional de Natación (FINA). Método: Los datos fueron retirados de la página electrónica de la FINA. Los 32 tiempos de la semifinal masculina y femenina fueron divididos en cuatro grupos: ocho varones clasificados para el final de la prueba analizada (G1M), ocho varones no clasificados (G2M), ocho mujeres clasificadas (G1F) y ocho mujeres no clasificadas (G2F). La velocidad de nado para cada parcial de 50 m fue estimada por el cociente entre 50 m y su respectivo tiempo. Fueron calculados los coeficientes de variación del tiempo de los cuatro parciales de 50 m y comparadas entre los grupos (ANOVA). Se observó el tamaño de efecto con d de Cohen. Se analizó la correlación entre el rendimiento (tiempo total) y el tiempo de cada parcial de 50 m. Resultados: El coeficiente de variación para los parciales de 50 m fue menor en los grupos finalistas de ambos sexos (G1M e G1F) y menor para las mujeres. El tercer parcial de 50 m presentó mayor correlación con el rendimiento final en ambos sexos. La velocidad media disminuyó a lo largo de la prueba en ambos grupos. Conclusión: El ritmo para el mejor rendimiento en la prueba es evitar la variación del tiempo a lo largo de los 200 m mariposa y el entrenamiento debe estar dirigido a la mejora de la condición física es ese parcial (150‐200 m).

From a basic circuit of two meshes with properly chosen resistive, inductive and capacitive element we present here an experimental comprobation of the Kirchhoff's laws for AC currents. The data acquisition and processing, as well as the presentation of the results proposed here is a meaningful contribution from the experimental point of view in this subject.

A partir de un circuito básico de dos mallas con elementos resistivos, inductivos y capacitivos, adecuadamente elegidos, se muestra la comprobación de las leyes de Kirchhoff de tensión y corriente para alterna. La adquisición y procesamiento de los datos, como así también la presentación de los resultados hace que la propuesta signifique un aporte didáctico desde lo experimental y para la enseñanza del tema.

Este trabalho investiga a resposta de dois pórticos planos de concreto armado à perda de uma coluna e sua capacidade de resistir ao colapso progressivo. A análise não linear dinâmica é realizada utilizando um elemento de viga baseado na teoria de Euler/Bernoulli com seção transversal discretizada em camadas. A não linearidade física é representada através de relações constitutivas unidimensionais, incluindo efeitos viscoplásticos. A não linearidade geométrica é incorporada através de uma formulação corrotacional. Os pórticos foram projetados de acordo com os requisitos mínimos das normas de projeto/construção de estruturas de concreto armado Europeias (fib [1-2], Eurocode 2 [3]) e Brasileiras (NBR 6118 [4]). As combinações de carregamento consideradas na análise de colapso progressivo estão de acordo com DoD [5]. O trabalho verifica se os requisitos mínimos das normas consideradas são suficientes para garantir a robustez e a segurança estrutural e aponta também as diferenças mais relevantes em termos da suscetibilidade dos pórticos ao colapso progressivo.

This work investigates the response of two reinforced concrete (RC) plane frames after the loss of a column and their potential resistance for progressive collapse. Nonlinear dynamic analysis is performed using a multilayered Euler/Bernoulli beam element, including elasto-viscoplastic effects. The material nonlinearity is represented using one-dimensional constitutive laws in the material layers, while geometrical nonlinearities are incorporated within a corotational beam formulation. The frames were designed in accordance with the minimum requirements proposed by the reinforced concrete design/building codes of Europe (fib [1-2], Eurocode 2 [3]) and Brazil (NBR 6118 [4]). The load combinations considered for PC analysis follow the prescriptions of DoD [5]. The work verifies if the minimum requirements of the considered codes are sufficient for enforcing structural safety and robustness, and also points out the major differences in terms of progressive collapse potential of the corresponding designed structures.

In México, there is a network of 12 meteorological radars to monitor intense convective systems. Data from Cerro de la Catedral Doppler radar, 40 km northwest of México City, have been used to obtain precipitation rates estimates during intense precipitation events. Results show that although estimates are close to the observed precipitation in surface stations, a new configuration of the radar system is necessary to better capture the characteristics of intense storms, particularly at the foothills of the western mountains. The comparison between the estimate from the radar and a dense network of rain gauges shows that such deficiency may be related to systematic errors due to blockage (radar), but also to sampling problems (radar and rain gauge). The calibration by itself may not be enough since there is significant blockage with the radar at the peak of a high elevation but relatively distant mountain. Such location limits the scan capacity from making a good vertical coverage. The present characteristics of the elevation of the radar beam prevent the radar from estimating the amount of precipitation in the lowest part of the clouds, near the cloud base. A new configuration of the radar system for México City is proposed taking into account spatial coverage and propagation effects upon a standard atmosphere in a horizontally constant reflectivity field.

En México hay una red de 12 radares meteorológicos para monitorear sistemas convectivos intensos. Los datos del radar Doppler del Cerro de la Catedral, a 40 km al noroeste de la Ciudad de México, se han usado para obtener estimaciones de razón de precipitación durante eventos de precipitación intensa. Los resultados muestran que aunque las estimaciones son cercanas a lo observado en una red de estaciones de superficie, es necesaria una nueva configuración del sistema de radar para capturar mejor las características de las tormentas intensas, particularmente al pie de las montañas del oeste. La comparación entre las estimaciones del radar y una densa red de pluviómetros muestra que tal deficiencia puede estar relacionada con errores sistemáticos debidos al bloqueo del radar, pero también a problemas de muestro del radar y los pluviómetros. La calibración por sí misma puede no ser suficiente ya que con el radar en una montaña alta pero relativamente distante hay un bloqueo significativo. Tal ubicación limita la capacidad de muestreo para hacer una buena cobertura vertical. Las características actuales de la elevación del haz evitan que el radar estime la cantidad de precipitación en los niveles bajos de las nubes, cerca de la base de la nube. Se propone una nueva configuración del sistema de radar de la Ciudad de México tomando en cuenta la cobertura espacial y los efectos de propagación sobre una atmósfera estándar en un campo de reflectividad horizontalmente constante.

Introduction: The prevalence of hyponutrition in hospitalized patients in our setting is 53%. The therapeutic approach is controversial. Objectives: To determine whether an early nutritional intervention in hospitalized patients by means of oral nutritional support can improve their prognosis regarding decreased morbimortality and hospital stay. Material and methods: Randomized prospective study comprised by a treatment group and a control group of malnourished patients hospitalized at the Internal Medicine and Respiratory Medicine Departments. The nutritional diagnosis was made by using the Subjective Global Assessment. Groups B and C were assigned to receive the hospital diet according to their needs and pathology (control group) and the treatment group also received a standard nutritional supplement. We recorded the development of infections, pressure ulcers, hospitalization days, mortality, and weight. Results: We performed more than 1,700 Subjective Global Assessments. Five hundred and thirty seven patients (264 treated and 273 controls) were followed-up until hospital discharge or death. We did not find statistically significant differences in mortality, hospital stay, or occurrence of complications between the treatment group and the control group. The treatment group presented statistically significant weight increase as compared with the control group. Conclusions: We could not demonstrate benefits when using the oral nutritional supplement in terms of mortality, hospital stay, infectious complications, or pressure ulcers. The significant weight increase in the treatment group allowed us concluding that the supplement effectively treated hyponutrition in this group. This new clinical status implies a better prognosis, as it has already been shown. However, this could not be observed by means of the study parameters. Long-term studies are required to determine for how long this nutritional improvement can be sustained, implying a better prognosis in the long run.

Introducción: La desnutrición en pacientes hospitalizados tiene una prevalencia en nuestro medio del 53%. El enfoque terapéutico genera opiniones controvertidas. Objetivos: Determinar si una intervención nutricional precoz en los pacientes hospitalizados desnutridos mediante un suplemento nutricional oral mejora el pronóstico de los mismos en términos de disminución de la morbi-mortalidad y estadía hospitalaria. Material y métodos: Estudio prospectivo randomizado integrado por grupo tratado-grupo control de pacientes hospitalizados desnutridos en áreas de medicina y neumología. El diagnóstico nutricional se realizó mediante Valoración Global Subjetiva. Los B y C se asignaron a recibir la dieta hospitalaria acorde a sus necesidades y patología (grupo Control) y al grupo tratado se lo instó además a ingerir un suplemento nutricional estándar. Se controló la aparición de infecciones, úlceras de presión, días de hospitalización, mortalidad y peso. Resultados: Se realizaron más de 1.700 Valoraciones Globales Subjetivas. Se controlaron hasta el alta hospitalaria o el fallecimiento a 537 pacientes, 264 tratados y 273 controles. No se encontraron diferencias estadísticamente significativas en la mortalidad, estadía hospitalaria, o aparición de complicaciones entre el grupo tratado y el control. El grupo Tratado presentó un aumento de peso con respecto al Control estadísticamente significativo. Conclusiones: No pudieron demostrarse beneficios con el suplemento nutricional oral utilizado en términos de mortalidad, estadía hospitalaria o complicaciones infecciosas ni úlceras de presión. El aumento significativo en el peso, en el grupo Tratado permite concluir que el suplemento trató efectivamente la desnutrición en este grupo. Esta nueva situación clínica significa un mejor pronóstico, como ya ha sido demostrado El mismo sin embargo no pudo objetivarse mediante los parámetros planteados. Estudios a más largo plazo se requieren para valorar cuánto esta mejoría nutricional se puede mantener en el tiempo, y signifique una mejoría en el pronóstico a largo plazo.

The medial septum participates in the modulation of exploratory behavior triggered by novelty. Also, selective lesions of the cholinergic component of the septohippocampal system alter the habituation of rats to an elevated plus-maze without modifying anxiety indices. We investigated the effects of the intraseptal injection of the cholinergic immunotoxin 192 IgG-saporin (SAP) on the behavior of rats in an open-field. Thirty-nine male Wistar rats (weight: 194-230 g) were divided into three groups, non-injected controls and rats injected with either saline (0.5 µl) or SAP (237.5 ng/0.5 µl). Twelve days after surgery, the animals were placed in a square open-field (120 cm) and allowed to freely explore for 5 min. After the test, the rats were killed by decapitation and the septum, hippocampus and frontal cortex were removed and assayed for acetylcholinesterase activity. SAP increased acetylcholinesterase activity in the septum, hippocampus and frontal cortex and decreased the total distance run (9.15 ± 1.51 m) in comparison to controls (13.49 ± 0.91 m). The time spent in the center and at the periphery was not altered by SAP but the distance run was reduced during the first and second minutes (2.43 ± 0.36 and 1.75 ± 0.34 m) compared to controls (4.18 ± 0.26 and 3.14 ± 0.25 m). SAP-treated rats showed decreased but persistent exploration throughout the session. These results suggest that septohippocampal cholinergic mechanisms contribute to at least two critical processes, one related to the motivation to explore new environments and the other to the acquisition and storage of spatial information (i.e., spatial memory).

Sea anemones are a rich source of biologically active substances. In crayfish muscle fibers, Bunodosoma cangicum whole venom selectively blocks the I K(Ca) currents. In the present study, we report for the first time powerful hemolytic and neuroactive effects present in two different fractions obtained by gel-filtration chromatography from whole venom of B. cangicum. A cytolytic fraction (Bcg-2) with components of molecular mass ranging from 8 to 18 kDa elicited hemolysis of mouse erythrocytes with an EC50 = 14 µg/ml and a maximum dose of 22 µg/ml. The effects of the neuroactive fraction, Bcg-3 (2 to 5 kDa), were studied on isolated crab nerves. This fraction prolonged the compound action potentials by increasing their duration and rise time in a dose-dependent manner. This effect was evident after the washout of the preparation, suggesting the existence of a reversible substance that was initially masking the effects of an irreversible one. In order to elucidate the target of Bcg-3 action, the fraction was applied to a tetraethylammonium-pretreated preparation. An additional increase in action potential duration was observed, suggesting a blockade of a different population of K+ channels or of tetraethylammonium-insensitive channels. Also, tetrodotoxin could not block the action potentials in a Bcg-3-pretreated preparation, suggesting a possible interaction of Bcg-3 with Na+ channels. The present data suggest that B. cangicum venom contains at least two bioactive fractions whose activity on cell membranes seems to differ from the I K(Ca) blockade described previously.