Triceps and subscapular skinfold thicknesses percentiles and cut-offs for overweight and obesity in a population-based sample of schoolchildren in Bogota, Colombia

OBJECTIVES: The aims of this study were to establish a Colombian smoothed centile charts and LMS tables for tríceps, subscapular and sum tríceps+subscapular skinfolds; appropriate cut-offs were selected using receiver operating characteristic analysis based in a populationbased sample of schoolchildren in Bogota, Colombia and to compare them with international studies. METHODS: A total of 9 618 children and adolescents attending public schools in Bogota, Colombia (55.7% girls; age range of 9–17.9 years). Height, weight, body mass index (BMI), waist circumference, triceps and subscapular skinfold measurements were obtained using standardized methods. We have calculated tríceps+subscapular skinfold (T+SS) sum. Smoothed percentile curves for triceps and subscapular skinfold thickness were derived by the LMS method. Receiver operating characteristics curve (ROC) analyses were used to evaluate the optimal cut-off point of tríceps, subscapular and sum tríceps+subscapular skinfolds for overweight and obesity based on the International Obesity Task Force (IOTF) definitions. Data were compared with international studies. RESULTS: Subscapular, triceps skinfolds and T+SS were significantly higher in girls than in boys (P <0.001). The median values for triceps, subscapular as well as T+SS skinfold thickness increased in a sex-specific pattern with age. The ROC analysis showed that subscapular, triceps skinfolds and T+SS have a high discrimination power in the identification of overweight and obesity in the sample population in this study. Based on the raw non-adjusted data, we found that Colombian boys and girls had high triceps and subscapular skinfolds values than their counterparts from Spain, UK, German and US. CONCLUSIONS: Our results provide sex- and age-specific normative reference standards for the triceps and subscapular skinfold thickness values in a large, population-based sample of 3 schoolchildren and adolescents from an Latin-American population. By providing LMS tables for Latin-American people based on Colombian reference data, we hope to provide quantitative tools for the study of obesity and its complications.

Aplicaciones de los modelos de predicción bio-inspirados en la administración

Las organizaciones y sus entornos son sistemas complejos. Tales sistemas son difíciles de comprender y predecir. Pese a ello, la predicción es una tarea fundamental para la gestión empresarial y para la toma de decisiones que implica siempre un riesgo. Los métodos clásicos de predicción (entre los cuales están: la regresión lineal, la Autoregresive Moving Average y el exponential smoothing) establecen supuestos como la linealidad, la estabilidad para ser matemática y computacionalmente tratables. Por diferentes medios, sin embargo, se han demostrado las limitaciones de tales métodos. Pues bien, en las últimas décadas nuevos métodos de predicción han surgido con el fin de abarcar la complejidad de los sistemas organizacionales y sus entornos, antes que evitarla. Entre ellos, los más promisorios son los métodos de predicción bio-inspirados (ej. redes neuronales, algoritmos genéticos /evolutivos y sistemas inmunes artificiales). Este artículo pretende establecer un estado situacional de las aplicaciones actuales y potenciales de los métodos bio-inspirados de predicción en la administración.

Valores de referencia de la fuerza prensil en escolares colombianos. Estudio FUPRECOL

The primary aim of this study was to generate normative handgrip strength (HG) data for 10- to 17.9-year-olds. The secondary aim was to determine the relative proportion of Colombian children and adolescents that fall into established Health Benefit Zones (HBZ). This cross-sectional study is enrolling 7268 schoolchildren (boys n=3129 and girls n=4139, age 12.7 (2.4) years old. HG was measured using a hand dynamometer with an adjustable grip. Five HBZs (Needs Improvement, Fair, Good, Very Good, and Excellent) have been established that correspond to combined-HG. Centile smoothed curves, percentile and tables for the 3rd, 10th, 25th, 50th, 75th, 90th and 97th percentile were calculated using Cole’s LMS method. HG peaked in the sample at 22.2 (8.9) kg in boys and 18.5 (5.5) kg in girls. The increase in HG was greater for boys than for girls, but the peak HG was lower in girls than in boys. The HBZ data indicated that a higher overall percentage of boys than girls at each age group fell into the “Needs Improvement” zone, with differences particularly pronounced during adolescence. Our results provide, for the first time, sex- and age-specific HG reference standards for Colombian schoolchildren aged 9-17.9 years.

Prevalencia e incidencia de cáncer en habitantes de Sibaté, y georeferenciación de casos 2010-2014

Introducción: El Cáncer es prevenible en algunos casos, si se evita la exposición a sustancias cancerígenas en el medio ambiente. En Colombia, Cundinamarca es uno de los departamentos con mayores incrementos en la tasa de mortalidad y en el municipio de Sibaté, habitantes han manifestado preocupación por el incremento de la enfermedad. En el campo de la salud ambiental mundial, la georreferenciación aplicada al estudio de fenómenos en salud, ha tenido éxito con resultados válidos. El estudio propuso usar herramientas de información geográfica, para generar análisis de tiempo y espacio que hicieran visible el comportamiento del cáncer en Sibaté y sustentaran hipótesis de influencias ambientales sobre concentraciones de casos. Objetivo: Obtener incidencia y prevalencia de casos de cáncer en habitantes de Sibaté y georreferenciar los casos en un periodo de 5 años, con base en indagación de registros. Metodología: Estudio exploratorio descriptivo de corte transversal,sobre todos los diagnósticos de cáncer entre los años 2010 a 2014, encontrados en los archivos de la Secretaria de Salud municipal. Se incluyeron unicamente quienes tuvieron residencia permanente en el municipio y fueron diagnosticados con cáncer entre los años de 2010 a 2104. Sobre cada caso se obtuvo género, edad, estrato socioeconómico, nivel académico, ocupación y estado civil. Para el análisis de tiempo se usó la fecha de diagnóstico y para el análisis de espacio, la dirección de residencia, tipo de cáncer y coordenada geográfica. Se generaron coordenadas geográficas con un equipo GPS Garmin y se crearon mapas con los puntos de la ubicación de las viviendas de los pacientes. Se proceso la información, con Epi Info 7 Resultados: Se encontraron 107 casos de cáncer registrados en la Secretaria de Salud de Sibaté, 66 mujeres, 41 hombres. Sin división de género, el 30.93% de la población presento cáncer del sistema reproductor, el 18,56% digestivo y el 17,53% tegumentario. Se presentaron 2 grandes casos de agrupaciones espaciales en el territorio estudiado, una en el Barrio Pablo Neruda con 12 (21,05%) casos y en el casco Urbano de Sibaté con 38 (66,67%) casos. Conclusión: Se corroboro que el análisis geográfico con variables espacio temporales y de exposición, puede ser la herramienta para generar hipótesis sobre asociaciones de casos de cáncer con factores ambientales.

Normative reference of standing long jump for Colombian schoolchildren aged 9-17.9 years: The FUPRECOL study

El propósito del presente estudio era generar los valores normativos de salto largo para niños de 9-17.9 años, e investigar las diferencias de sexo y grupo de edad

Semi-implicit finite strain constitutive integration and mixed strain/stress control based on intermediate configurations

A new semi-implicit stress integration algorithm for finite strain plasticity (compatible with hyperelas- ticity) is introduced. Its most distinctive feature is the use of different parameterizations of equilibrium and reference configurations. Rotation terms (nonlinear trigonometric functions) are integrated explicitly and correspond to a change in the reference configuration. In contrast, relative Green–Lagrange strains (which are quadratic in terms of displacements) represent the equilibrium configuration implicitly. In addition, the adequacy of several objective stress rates in the semi-implicit context is studied. We para- metrize both reference and equilibrium configurations, in contrast with the so-called objective stress integration algorithms which use coinciding configurations. A single constitutive framework provides quantities needed by common discretization schemes. This is computationally convenient and robust, as all elements only need to provide pre-established quantities irrespectively of the constitutive model. In this work, mixed strain/stress control is used, as well as our smoothing algorithm for the complemen- tarity condition. Exceptional time-step robustness is achieved in elasto-plastic problems: often fewer than one-tenth of the typical number of time increments can be used with a quantifiable effect in accuracy. The proposed algorithm is general: all hyperelastic models and all classical elasto-plastic models can be employed. Plane-stress, Shell and 3D examples are used to illustrate the new algorithm. Both isotropic and anisotropic behavior is presented in elasto-plastic and hyperelastic examples.

Ravines in Angola. Causes and restraint methods

The Earth we know today was not always so. Over millions of years have undergone significant ch an g e s brought about by numerous geological phenomena aimed at your balance, some internal order, creating new geological formations and other external order smoothing formations previously created. From t h e tectonic standpoint, Angola is located in a relatively stable area which gives it a certain p ri v i l e g e w h e n compared with some Asian countries or even Americans where quite often occur earthquakes and volcanic eruptions. However, the same cannot be said in relation to the occurrence of an external geodynamics phenomena, such as the ravines, which in recent years has taken shape in many provinces, especially due to anthropogenic activity, giving rise to geological hazards, increasing the risk of damage in buildings and others infrastructures, losses direct or indirect in economic activities and loss of human lives. We understand that the reducing of these risks starts, in particular, by their identification, for later take preventive measures. This work is the result of some research work carried out by the authors through erosion courses of s o i l and stabilization of soils subject to erosion phenomena, carried out by Engineering Laboratory of Angola (LEA). For the realization of this work, we resorted to cartographic data query, literature, listening to s o m e o f the provincial representatives and local residents, as well as the observation in lo co o f s o m e af f e ct ed areas. The results allow us to infer that the main provinces affected by ravine phenomenon are located in Central and Northern highlands, as well as in the eastern region, and more recently in Cuando-Cub an go province. Not ruling out, however, other regions, such as in Luanda and Cabinda [1]. Relatively the causes, we can say that the ravines in Angola are primarily due to the combination of three natural factors: climate, topography and type of soil [2]. When we add the anthropogenic activit y , namely the execution of construction works, the drainage system obstructio n, exploration of m i n e ral s, agriculture and fires, it is verified an increasing of the phenomenon, often requiring immedi at e act i o n . These interventions can be done through structural or engineering measures and by the stabilization measures on the degraded soil cover [3]. We present an example of stabilization measures throu g h t h e deployment of a local vegetation called Pennisetum purpureum. It is expected that the results may contribute to a better understanding of the causes of the ravine phenomenon in Angola and that the adopted stabilization method can be adapted in other affected provinces in order to prevent and making the contention of the ravines.

Colocated multiple-input multiple-output radars for smart mobility

In recent years, radars have been used in many applications such as precision agriculture and advanced driver assistant systems. Optimal techniques for the estimation of the number of targets and of their coordinates require solving multidimensional optimization problems entailing huge computational efforts. This has motivated the development of sub-optimal estimation techniques able to achieve good accuracy at a manageable computational cost. Another technical issue in advanced driver assistant systems is the tracking of multiple targets. Even if various filtering techniques have been developed, new efficient and robust algorithms for target tracking can be devised exploiting a probabilistic approach, based on the use of the factor graph and the sum-product algorithm. The two contributions provided by this dissertation are the investigation of the filtering and smoothing problems from a factor graph perspective and the development of efficient algorithms for two and three-dimensional radar imaging. Concerning the first contribution, a new factor graph for filtering is derived and the sum-product rule is applied to this graphical model; this allows to interpret known algorithms and to develop new filtering techniques. Then, a general method, based on graphical modelling, is proposed to derive filtering algorithms that involve a network of interconnected Bayesian filters. Finally, the proposed graphical approach is exploited to devise a new smoothing algorithm. Numerical results for dynamic systems evidence that our algorithms can achieve a better complexity-accuracy tradeoff and tracking capability than other techniques in the literature. Regarding radar imaging, various algorithms are developed for frequency modulated continuous wave radars; these algorithms rely on novel and efficient methods for the detection and estimation of multiple superimposed tones in noise. The accuracy achieved in the presence of multiple closely spaced targets is assessed on the basis of both synthetically generated data and of the measurements acquired through two commercial multiple-input multiple-output radars.

Advanced voxel-based CAD modelling for FSI simulations for automotive structures design

Additive Manufacturing (AM) is nowadays considered an important alternative to traditional manufacturing processes. AM technology shows several advantages in literature as design flexibility, and its use increases in automotive, aerospace and biomedical applications. As a systematic literature review suggests, AM is sometimes coupled with voxelization, mainly for representation and simulation purposes. Voxelization can be defined as a volumetric representation technique based on the model’s discretization with hexahedral elements, as occurs with pixels in the 2D image. Voxels are used to simplify geometric representation, store intricated details of the interior and speed-up geometric and algebraic manipulation. Compared to boundary representation used in common CAD software, voxel’s inherent advantages are magnified in specific applications such as lattice or topologically structures for visualization or simulation purposes. Those structures can only be manufactured with AM employment due to their complex topology. After an accurate review of the existent literature, this project aims to exploit the potential of the voxelization algorithm to develop optimized Design for Additive Manufacturing (DfAM) tools. The final aim is to manipulate and support mechanical simulations of lightweight and optimized structures that should be ready to be manufactured with AM with particular attention to automotive applications. A voxel-based methodology is developed for efficient structural simulation of lattice structures. Moreover, thanks to an optimized smoothing algorithm specific for voxel-based geometries, a topological optimized and voxelized structure can be transformed into a surface triangulated mesh file ready for the AM process. Moreover, a modified panel code is developed for simple CFD simulations using the voxels as a discretization unit to understand the fluid-dynamics performances of industrial components for preliminary aerodynamic performance evaluation. The developed design tools and methodologies perfectly fit the automotive industry’s needs to accelerate and increase the efficiency of the design workflow from the conceptual idea to the final product.

Raffinamento della posizione ottenuta da un GPS tramite misure di fase

Questa tesi elabora un sistema di filtraggio delle pseudodistanze calcolate da un ricevitore GPS, al fine di ottenere un miglior posizionamento. Infatti, dopo aver analizzato e quindi filtrato i dati in ingresso tramite l’impiego delle misure di fase, si può ottenere una precisione nell’ordine dei centimetri. La tecnica di filtraggio prende il nome di carrier-smoothing e permette di selezionare le misure di pseudorange mediante le misure di ADR (Accumulated Delta Range) grazie all’applicazione di una struttura a filtro complementare. Per svolgere questo tipo di lavoro, non è stato necessario l’utilizzo di un ricevitore GPS fisico, ma è stato realizzato, nell’ambiente Matlab/Simulink, un simulatore GNSS (Global Navigation Satellite System) che sostanzialmente emula quello che farebbe un ricevitore.