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Social networks have become a major communication channel for organizations, including those focused on security and defense. This article specifically examines how the Spanish Armed Forces and State Security Forces communicate on Twitter, with the aim of analyzing the factors that influence engagement with their tweets. A model validated with a sample of 14,540 tweets shows the role that a series of variables related to rational and emotional communication attributes has. These variables are estimated utilizing techniques such as Python and VBA. Subsequently, a logistic model using IBM SSPS estimates the effect of each variable on the probability that a tweet will lead to more or less engagement. The results show that followers of military accounts, such as the Army, tend to have higher rates of interaction than followers of other accounts, even though military accounts have fewer total followers than police accounts. Furthermore, the results confirm the importance of using both rational and emotional stimuli for a message to be effective. To increase engagement, information provided by organizations should use elements such as hyperlinks, emojis, and photographs, and refer to topics that appeal to individuals’ emotions, such as patriotism. [ABSTRACT FROM AUTHOR]

In order to propose a statistical methodology that allows to model asymmetric data using the Lévy distribution, a simulation study is presented under nine different scenarios to evaluate the estimation of the parameters of the distribution in the two approaches of statistics (Classical and Bayesian). The probability distributions Log-Normal, Lévy and Lévy Standard were considered to model the behavior of two real data sets with positive asymmetry, finding that the Lévy distribution fitted well to the proposed data set, therefore the Lévy distribution can be considered as a candidate to adjust asymmetric data with the presence of extreme values. [ABSTRACT FROM AUTHOR]

Social relations and postmarital residence patterns in northwestern Argentina are investigated by analyzing phenotypic traits in Puna de Jujuy, Quebrada de Humahuaca, Valle Calchaquí and Selvas Occidentales. The study includes 29 archaeological sites and 947 individuals dated from 500 BC to 1450 AD. The distribution of the sexes and their phenotypic differences between subregions and between sites were evaluated using discriminant analysis. The postmarital residence pattern was determined by the relationship between sex variances, D² values and the estimation of Fst statistics to establish the influence of migration on genetic variation between and within populations. The results suggest patterns of matrilocal and patrilocal residence determined by different migration rates and by the effective size of both sexes. The evidences obtained allow explaining the factors that determine the social structure of the populations in the late phase of the development of the Argentine Northwest. [ABSTRACT FROM AUTHOR]

In this work we develop statistical inference procedures, based on bootstrap and permutation tests, for the European Customer Satisfaction Index (ECSI). The main objective is to fill an existent gap, to the best of our knowledge, in statistical methods for confidence interval estimation of one ECSI, for hypothesis testing comparing two or more ECSIs, and for ranking a set of ECSIs. The procedures proposed is applied to a study of higher education students' satisfaction conducted in Veracruz University (México). The results indicate that the procedures of statistical inference are feasible and straightforward to implement with R. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of applying the optimization of mean-variance mapping technique in the problem of estimating the parameters of the soil model of two horizontal layers. This problem consists of determining the parameters of the soil model from experimental measurements of apparent resistivity obtained with Wenner method, minimizing the mean square error between values of the experimental and theoretical resistivity curves, which are calculated with mathematical expressions and soil parameters acquired through the optimization of mean-variance mapping technique. Several tests were carried out with resistivity measurements that correspond to different soil types, the results were contrasted with those reported in the technical literature and metaheuristics implemented. In conclusion, according to the results, the performance of the optimization of mean-variance mapping technique was found to be superior than other analyzed optimization techniques. [ABSTRACT FROM AUTHOR]

This research aimed to identify content knowledge (common, advanced and specialised) of correlation and regression in a sample of 65 prospective secondary and high school teachers. The participants' written productions in different tasks proposed within a statistical project based on United Nations Data were analysed. Results suggest a good estimation of correlation and identification of the model of fit (common knowledge), correct ordering of explanatory variables according to their predictive value, some difficulty in explaining correlation by relationships different from causality (advanced knowledge), and a reasonable analysis of the project didactic suitability (specialised knowledge). We also inform of some biases, as well as the effect of task variables in the responses. [ABSTRACT FROM AUTHOR]

The study of mathematical knowledge in different contexts has acquired relevance due to the current interest in students' ability to use mathematics in solving real life problems. Thus, the purpose of this research is to characterize the knowledge in use in the measurement of inaccessible distances in Johann Stöffler's Elucidatio Fabricoe Ususque Astrolabii, published in 1513. The theoretical model used considers the study of the constitution of knowledge through the analysis of its genesis, development and transversality. The results reveal in the analyzed work an episteme of the measurement of inaccessible distances that includes both the search for a suitable reason to carry out the measurement and the dynamic analysis of the behavior of the shadows or the visual rays in the estimation of inclinations. This episteme is critical for the understanding of this mathematical knowledge in problem solving. [ABSTRACT FROM AUTHOR]

A class of estimators is determined. It contains important families of ratio estimators. The belonging to it is characterized by means of a parametric vector. It allows identifying that more than a dozen of estimators are particular cases. Their behavior when ranked set sampling is used is established by fixing the gains in accuracy of them. Numerical experiments establish which is the performance of them in four applications and by generating normal, exponential and uniform populations. [ABSTRACT FROM AUTHOR]

Records of milk production adjusted to 305 d, adult equivalent of the first lactation and two milking were used. Those come from the National Breeding in Mexico PNMG (n= 163.885), which includes records of the Holstein Association of Mexico (AHM) (n= 43.668) and National Bank of Dairy Information (BNIL) (n= 120.217). Best Linear Unbiased Predictor method was used to predict breeding values (VG) of animals. ASREML software was used with an animal model that included herd-year group-season as fixed effect and animal and residue as random effects. Averages of VG per sire were estimated weighted by the number of daughters and unweighted for PNMG, AHM and BNIL. Also, we estimated the weighted average of the sires VG of the PNMG according to their country of origin (USA, Canada, Other, Mexico). We also estimated the average of VG and phenotypic values (VF) for dairy cows. The average of VF and VG for cows PNMG, AHM and BNIL increased between 2007 and 2011. Breeders of the AHM chose sires with greater VG than the BNIL. However, breeders of BNIL used sires with high VG used more frequently. The VG for foreign sires were higher than national sires and were more commonly used by farmers. [ABSTRACT FROM AUTHOR]

Given the need to find a technique whose application would be easy for an estimate, we analyzed T-Shirt estimation technique, and from it was drawn in order to extract features and variables to arrive at estimates more realistic, across the analysis of historical data from recent executions of projects for inclusion in the technique and improve the model. To accomplish this, we applied a methodology descriptive, which analyzed software development projects completed, which were extracted variables that were assessed through surveys to determine their relevance in an effort estimation, and effort times to build the model. The result is shown in the software application for the project, where it joins the estimation technique to the valuation of the variables identified, so that these are part of the general model. [ABSTRACT FROM AUTHOR]

This article spells out the methodological and technical problems that arise when building a database on politicians holding a position in representative institutions. Using the example of an existing database of Spanish MPs (1980-2011 ), the authors discuss the criteria they have used and the solutions applied to solve several challenges: parsimony, social desirability, multicollinearity, temporality control, adjustment to electoral results, level of information, and electoral cycles. Some descriptive statistics related to the data as well as research questions regarding political elites are also put forward. [ABSTRACT FROM AUTHOR]

Objective. Estimate the genetic parameters for milk traits in a Romanian local sheep population Teleorman Black Head. Material and methods. Records of 262 sheep belonging to 17 rams and 139 ewes were used in the study. The following traits were investigated: milk yield, fat yield, protein yield, fat percentage and protein percentage. The genetic parameters were estimated using the Restricted Maximum Likelihood method, with a model including maternal effects. Results. The results from our study revealed that direct heritability estimates were moderate for milk yield (0.449), fat yield (0.442), protein yield (0.386) while for protein percentage (0.708) and fat percentage (0.924) were high. The high direct and maternal genetic correlation was between milk yield and protein yield (0.979, 0.973) and between protein yield and fat yield (0.952, 0.913) while the phenotypic correlation between the milk yield and fat yield (0.968), the milk yield and protein yield (0.967), fat yield and protein yield (0.936) was high and positive. Conclusions. The genetic parameters are important in selection program on this breed for genetic improvement. [ABSTRACT FROM AUTHOR]

Background: Pediatric obesity is a major health problem around the globe. It has increased in the last decades up to 30 % (in 2010). The aim of this study was to establish the prevalence of overweight and obesity in children from zero to 14 years from three family medicine units and one school. Methods: A prospective study of prevalence, which included children of both sexes who assisted to three family medicine units and a junior high school. We assessed the somatometry and compared it in accordance to the World Health Organization 2006-2007 references and standards. Results: The overall overweight and obesity prevalence in 1624 children was 45.5 % (15.5 % of overweight and 29.9 % of obesity, respectively). A total of 354 of 840 women (42.1 %) and 385 of 784 men (49 %) had overweight and obesity (p < 0.05). In both sexes, we did not observed a difference in overweight (15.7, women; 15.4, men). However, with regards to obesity, women showed 26.4 versus 33.6 of men (p < 0.05). We observed only one family unit with major obesity prevalence, which probably had an initial overestimation. Conclusions: We found one of the highest prevalences of overweight and obesity in children at a national level: up to 45 % in a state of Mexican northwestern. Obesity doubled overweight, and it was almost 10 % higher in men than in women. [ABSTRACT FROM AUTHOR]

Background: If obesity results from the interaction of variables that involve the subject and his environment, the alternatives to face the problem could be very diverse. The objective of this study was to seek for the best predictive model of childhood obesity from energy ingestion, dietary habits and physical activity. Methods: Case control study of 99 obese and 100 healthy weight children (Center for Diseases Control criteria). Energy ingestion was estimated by means of a 24-hour recall, dietary and physical activity habits by validated questionnaires. A logistic regression analysis was made. Results: Variables independently associated to obesity were higher energy ingestion; lower frequency in mealtimes; having the afternoon lunch outside home; higher frequency of consumption of fat, junk food and sweetened beverages; lower time of moderate physical activity at school and at home; and increased time for homework and watching TV. The variables included in the regression model were energy intake; frequency of ingestion of fat, junk foods and sweetened beverages; and physical activity at home and at school. Conclusion: The diversity of associated variables underlines the complexity and multi-causal condition of obesity. [ABSTRACT FROM AUTHOR]

Background: Prevalence of overweight and obesity in children under 5 years can be affected by type of anthropometric indicator and selected threshold values. We assessed variation on estimates according to national and international regulations (NOM-031-SSA2-1999, NOM-008-SSA3-2010, GPC-SSA-025-08 and GPC-IMSS-029-08; WHO-2006, CDC-2000 and IOTF, respectively). Methods: Cross-sectional study in all the daycare centers (100 %) affiliated to Instituto Mexicano del Seguro Social-Nuevo León during June-December, 2010 (n = 11 141 children). Overweight and obesity were defined on the basis of each regulation, and total and stratified prevalences by age and sex were estimated. Results: According to national regulation, overweight/obesity estimates varied from 12 to 22 %, and to international normativity, from 3 to 14 %. The highest prevalence was given by NOM-008-SSA3-2010 and GPCSSA-025-08; and the lowest by WHO-2006. There were no differences by sex, but they existed by age; the highest discrepancy occurred in the 3.0-3.9 age group with 28 %. Conclusion: Health personnel and health policy makers should be aware of variation on estimates according to the definition employed. We recommend to standardize national regulation for pointing out overweight/obesity in preschoolers. [ABSTRACT FROM AUTHOR]

It is important to develop methods to improve the estimation of the soil moisture content, because of the impact in the weather and in various activities, such as agriculture and livestock. This task may be done by placing moisture instruments in the ground at different points and levels, through the use of remote sensing information, or running Hydrological Models. This work shows the results of the hydrological model CLASS U3M 1D calibration for Diamante and Parana stations in the province of Entre Rios. The hydraulic parameters were estimated through the information obtained from Argentina Soil Maps and the Pedotransfer Functions. The results were statistically significant at 99%, with correlation values between the observed series and the simulated series, in general, on the order of 0.6 and 0.7 for Diamante and between 0.3 y 1 for Parana. The root mean square error remained approximately in 0.06 m3/m3 for Diamante and between 0.03 m3/m3 and 0.18 m3/m3 for Parana depends on the simulation. After applying a variation in the evapotranspiration input variable, correlation values close to 1 were obtained when the models results were compared. [ABSTRACT FROM AUTHOR]

To be able to resolve tomographic inversion problems in travel time, it is necessary the construction of distance matrices containing information of survey array geometry, the discretized domain shape and the distance traveled by rays in each area elements that compose it. Domain considered are generally rectangular for ease of geometric resolution. In this work is circular due to the need to carry out investigation in columns of this shape. Distance matrices are used to solve the linear system, which leads to the determination of velocity values in each element of the domain. Taking in mind discretization, there are several possibilities for the construction of arrays of pixels: may those be defined in one quadrant and obtaining the rest by symmetry; build arrays using any size pixels independent of the quadrant, and finally construct distance matrices with square pixels. Each option will provide access to new research possibilities. In this work an original procedure was developed for the construction of matrices with elements of the last type. The procedure was validated with simulated data using the damped least squares solution (DLSS) method, which demonstrated the efficiency of the algorithm. [ABSTRACT FROM AUTHOR]

Binary logistic regression as an instrument for the prediction of immunological deterioration from nutritional indicators in persons infected with HIV-AIDS. In the evolution of infection with HIV diverse markers of progression have been used, of immunological, virological and genetic type. However, the significance of nutritional indicators for prognosis has been insufficiently studied. The objective of this investigation was to use binary logistic regression as a tool to find a mathematical model which would allow to predict the counting of CD4+ cells in persons infected with HIV-AIDS after a year's follow-up. 118 persons with HIV-AIDS were studied (initial time and after a year of evolution) which were classified in four subgroups according to the use or not use of antirretrovirals and the counting of CD4 at the initial time. Nutritional, biochemical and anthropometric variables were used, as well as the gradients between both observations. Binary logistic regression was applied, having as dependent variable the counting of CD4 as an immunological criterion of antirretroviral therapy. The logistical models found were adjusted according to the subgroup they belonged to, and they were compared to one another according to the goodness of fit and accuracy. The step-by-step method chose only the gradient of body mass index (IMC) as independent variable. The adjustment of the model allowed to propose a mathematical equation by subgroup in order to predict the need of antirretroviral therapy after a year. The groups which had initial values of CD4 < 350, even with an increase in IMC ran the risk of keeping immunological deterioration after a year. All models showed specificity values higher than those of sensitiveness, though models II and III were the best, as proved by the probabilities shown in ROC curves. The conclusion is that the IMC gradient in a year of evolution might be used in a logistical mathematical model to predict the need of antirretroviral therapy in individuals with HIV-AIDS. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the psychometric properties of Dyadic Adjustment Scale (DAS). The answers of 456 Spaniards (228 couples, 45 of which were satisfied with their relationship) were factor analysed through a confirmatory factorial analysis. It was found that a tetra factorial model, similar to the one proposed by the author in his original study, fitted significantly better than a Hierarchic or monofactorial model. The internal consistency (Cronbach's?) of the first order factors ranged between .60 and .84. Gender-separated analysis determined that the goodness of fit was equally good both in men and women and also between harmony and conflict sample. Cut-off scores for each dimension of the questionnaire were established. The results of this study are similar, as far as cut-off scores and internal consistency are concerned, to those of Spanier's original study and adaptation studies of the questionnaire in other countries. Its use can be recommended with populations of ill adjusted couples, both in the initial assessment phase, and as a measure of their evolution, after therapeutic interventions, and to establish possible comparisons with couples in conflict from other countries. [ABSTRACT FROM AUTHOR]

El presente estudio intenta resumir el estado de la ciencia respecto a la pobreza, la desigualdad y las relaciones entre las mismas y otras variables, tomando como referencia el análisis histórico para el mundo y las cuentas específicas del Perú. Aprovechando la más reciente data (2007-2012), calculamos la elasticidad de la relación crecimiento económico-pobreza, así como estimamos las tasas de crecimiento necesarias para lograr el 15 por ciento de cuentas para el 2016. [ABSTRACT FROM AUTHOR]

The knowledge of the structure and function of the adipose tissue is not only relevant in relation with its role played in the lipidic metabolism or in endocrine disorders as diabetes. The fat tissue plays also an important role as mechanical support and in the modelling of organic contours (facial, for example); therefore its interest in the field of the Plastic Reconstructive and Aesthetic Surgery. The quantitative methodology has been employed from the very beginning of the histological science. The present study deals with the stereology as a set of unbiased tools that employ intrinsic geometrical features of the objects to quantify. In short, the stereology consists in a pool of morphometric methods that obtain tridimensional information from bidimensional elements (the tissue sections) using the geometrical characteristics of the structures of interest. We describe some stereological procedures leading to the unbiased estimate of: volume fraction of the adipose tissue, the relative number of adipocytes, and the relative length of microvessels of the adipose tissue. [ABSTRACT FROM AUTHOR]

The labor market in Colombia performs better than suggested by the high underemployment rate which is tantamount to "low quality employment". Given the wage gap among those that complain about their wages and those that do not, the effective underemployment rate in Colombia should be much lower than that reported by official statistics according to which a fourth part of the labor force is income-related underemployed. To arrive to this conclusion, the wages of private salaried workers and public servants were estimated for both income-related underemployed for and not underemployed at all. The wage gap was estimated by means of the Mincer equation, the Blinder-Oaxaca decomposition and the approach of Ñopo (2008). The results show a wage gap between 40% and 44% but the unexplained component is much smaller (between 36% and 40% of it). Although some underemployed might have reasons to be regarded as such, we provide evidence in the sense that the higher portion of the gap is explained by human capital variables and other controls. The differential is more neatly observed in the higher part of the wage distribution (the higher the age and schooling, the higher the unexplained component of it) and in the sectors of mines, transport and building. [ABSTRACT FROM AUTHOR]

This article introduces the problematization of estimating large numbers. We study the presence of mathematic modeling processes and the influence of context in problem solving that secondary education students propose. As a result of a qualitative analysis, we divided it into three categories: solution-focused question, strategies and a successful problem solving. This analysis allows us to study the relationships that exist between the strategies proposed by students and the context given when solving a mathematical sentence. We also study the modeling of those situations. From the data collection in this study, we implied that the context may influence the answers students propose for problem solving. We conclude that these kinds of problems may be used as a tool for introducing mathematical modeling in the classroom. [ABSTRACT FROM AUTHOR]

This paper describes a novel algorithm for estimating the magnetization inductance and winding capacitance of each phase of transformer from the data of frequency response curve, using a transformer core model. The use of the model applied to the three measures for each phase of the transformer allows locating and quantifying a possible failure at low frequencies without need for reference FRA measures. It describes the model, the algorithm to obtain the parameters of each phase and its application in the interpretation of low-frequency variations of curve FRA, finally show two cases of application. [ABSTRACT FROM AUTHOR]

A difficult problem to address is to determine the minimum sample size and the numbers of bootstrap samples to be used for obtain sampling distribution that makes a better fit to the true sampling distribution using the bootstrap methodology. We evaluate the effect of sample size and the number of bootstrap samples in the estimates of the mean, variance and some quantiles for probability distribution under different measures of skewness. We give some recommendations for using the non-parametric bootstrap. [ABSTRACT FROM AUTHOR]

The results of the optimization of the thermal efficiency of a Robinson engine applying the Senft-Petrescu- Schmidt model are presented. This is based on the coupling of the Senft-Schmidt and the Petrescu models, used for the calculation of power in Stirling cycle engines. The proposed model involves both thermodynamic and geometric parameters and allows estimating the overall pressure losses by friction and by flow throttling. Based on data from a prototype of a Robinson engine of about 2 W of power, a theoretical analysis of its main parameters and the optimization of thermal efficiency, based on the minimum entropy generation, were performed. After the optimization was done, the thermal efficiency of the engine increased to more than the double. It is concluded that the proposed Senft-Schmidt-Petrescu model may be useful in the analysis and redesign of Robinson engines [ABSTRACT FROM AUTHOR]

Developing new potato varieties with a higher tuber quality is at present, the most important challenge to the cuban breeding program. On this sense, it is necessary to make an exhaustive evaluation to the main characters that can be affect this relevant attribute. So, the objective of this work was focusing to carry out an evaluation to a several potato varieties, representative from the cuban potato germplasm, for tuber quality properties to be used as parents in the potato breeding program. Seventy potato cultivated accessions from the cuban germplasm bank were used. Several quality tuber characters were evaluated: specific gravity, dry matter, reduced sugar, starch, tuber average weight, equatorial and long tuber diameter and sensorial evaluation. Media, standard deviation, minimum and maximum values and coefficient of variation were estimated. A Principal Components Analyses, by means a biplot representation, to known accessions clusters and selects it according its behaviour for tuber quality was used. A good behaviour for tuber quality were found in the collection (22,9 %). Values of dry matter content and starch content were higher to 19 and 12 %, respectively and sugar reducer content was very low (> 0,5 %). All the varieties could be used as parent in a breeding program to obtain new varieties for industrial processing or directly on the different production systems. Atlantic, Bellini, Cal White, Derby, Maranca, Romano, Santana and Slaney and the new cubans clons; 1-10-96, 2-31-95, 4-6-93 and 9-32-93 were the most remarkable genotypes. [ABSTRACT FROM AUTHOR]

This study presents the applications of two sequential Kalman filters to perform dynamic inverse problems regularization as the reconstruction of current distributions in neural activity in the brain, from electroencephalography signals. Kalman filter is an efficient algorithm for reconstructing of optimal way the current densities under some operation hypothesis, these are: the relationship between consecutives state; among a state and an observations, are both given by Gaussian distributions. The proposed methodology obtains consistent results with the state-of-the-art, when sources numbers rise; however, it needs a change in the estimation structure, since it can incur high computational cost. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to predict functional states in complex processes from the estimation of fuzzy membership degrees. The proposal integrates a static measure, such as the result of a fuzzy classifier trained with historical process data, and an estimation algorithm based on Markov theory for discrete events. The proposal, which can be integrated to the monitoring of complex systems, provides two stages: an off-line training stage to define the fuzzy classifier and the estimator; and an online stage where the classification of the current process situation and the estimation of the next functional state are performed. The proposal for the estimation of functional states allows using any fuzzy clustering method that provides the information required by the methodology. The proposed methodology was successfully tested on a monitoring system for a power transmission line and in the monitoring of a boiler system. [ABSTRACT FROM AUTHOR]

This paper estimates the (3DP gap in Venezuela by means of the structural VAR methodology and the Blanchard and Ouah decomposition for the period 1999:1-2010:4. We use quarterly data for the inflation rate, real GDP, unemployment rate, and oil prices. We identify fiscal and monetary innovations on the demand side and technological and labor market disturbances on the supply side. Empirical results reveal that even though there is a wide gap between real and potential (3DP at the beginning of the period, it tends to narrow towards the end of the period as a result of the rise in oil prices. The GDP sample forecast shows that this gap, eventually, could fall as a result of the contraction in economic activity during 2009 and 2010. [ABSTRACT FROM AUTHOR]

Currently there are no studies on the damage caused by Rhizoctonia solani Kuhn [teleomorph Thanatephorus cucumeris (Frank) Donk] on the yield components of common bean (Phaseolus vulgaris L.), therefore the aim of this study was to quantify the reduction in grain yield and its yield components caused by natural infection of web blight in different bean genetic material, in summer 2011, in Quevedo city, Los Rios, Ecuador. Were used lines Cf4 0-0-2-1, Cf6 0-0-4-9, Cf6 0-0-4-8, SER 03 and SER 08, and two varieties FTS Soberano and BRS Valente. Incidence (%) and percentage of severity and number of lesions leaflet-1 were quantified, and these values used to calculate the area under the disease progress curve (AUDPC). Also, it was quantified the number of lesions leaflet-1 during reproductive stages R7 and R8. After harvest, it was quantified the number of nodes, pods and seeds per plant, seeds per pod per plant, and yield (kg ha-1). For estimating the damage caused by the disease were used integral and critical point models, performing regression analysis between disease intensity (independent variables), and grain yield and its components (dependent variable) obtaining the equations of damage function. The results of this research showed that integral and critical point models, are an important tool for estimating damage by web blight on yield components being more evident in the number of seeds per plant (p<0.01). [ABSTRACT FROM AUTHOR]

Los sensores de reflexión ópticos para medir distancia se caracterizan por la no linealidad de la salida. Esta condición deben asumirla las unidades de procesamiento donde son utilizados. El presente artículo tiene por objeto reducir el costo computacional, en términos de espacio de memoria y tiempo de procesamiento, en la linealización de la salida de los sensores para ser usados en sistemas embebidos de bajo costo. Los resultados de dos diferentes sensores indican que la curva exponencial estimada se puede ajustar usando redes neuronales con funciones de base radial con una reducción de más del 50 % en el tiempo de procesamiento. Para el diseño de la red se estudió la eficiencia respecto al tamaño de la red y a la distribución de los centroides con resultados importantes. La reducción del tiempo y de espacio lograda permite aprovechar los recursos del sistema en otras tareas, al mismo tiempo que posibilita aumentar la frecuencia de muestreo en la adquisición. [ABSTRACT FROM AUTHOR]

This case was developed with the objective of makes a prediction equation of adipose mass percent in values anthropometric, to star off the predetermined slant of instruments of impedance bioelectric TANITA. This is based in the premise that every day the importance of estimation about the fat mass in a clinic level, it is getting bigger and bigger, for this reason a population of twenty eight people with age range fluctuate among twenty to twenty eight was evaluated, they were part of "Escuela de Caballerfa Blindada" in the city of Quillota. The Pertinent measurements for the estimation of fatty mass were realized through of impedance bioelectric and anthropometry, the results made big differences between both methods, obtaining an index of correlation coefficient a 0.13 and a person correlation of 0.34. This suggests that possible creation does not accomplish with the criteria homescedasticity, in brief, this is unsafe. [ABSTRACT FROM AUTHOR]

Actualmente, el análisis de clasificación de calidad de la canal depende en gran medida de la edad del animal; sin embargo, el patrón en México es demasiado impreciso, pues sólo requiere identificar si éste es menor o mayor a 30 meses. Esta falta de precisión genera la necesidad de sistemas objetivos para medir la madurez fisiológica. El propósito de esta investigación fue estimar de manera precisa el porcentaje de osificación del cartílago en la 12ava costilla, como un indicador de madurez ósea en canales de bovino, utilizando un esquema electrónico por visión artificial. En el esquema desarrollado se aprovecha la mayor fluorescencia que genera el cartílago, en comparación con la del hueso y la grasa, sobresaliendo claramente la región del cartílago, desarrollando algoritmos de procesamiento de imágenes para analizar esta región, y estimar de manera precisa el porcentaje de osificación, y por tanto la edad fisiológica de la canal. El sistema de visión artificial desarrollado permitió evaluar la madurez ósea de una canal en menos de un segundo, y la información obtenida fue utilizada para establecer la clasificación electrónica de la canal en menos de cinco segundos. [ABSTRACT FROM AUTHOR]

The structural engineers calculate the seismic capacity of reinforced concrete frames with the geometry of the structural elements and with the mechanical properties of the materials. The most important mechanical properties of the concrete and the steel used to estimate this capacity are: elasticity modulus (E) and compressive strength (f 'c) of the concrete, yield stress (Fy) and maximum stress of the steel (Fu) and its strains. Based on these facts, results of more than 1,500 concrete compression tests (only from Bogotá), and more than 900 steel tension tests were statistically studied. Then, five stories reinforced concrete buildings were modeled (finite element analysis - frame elements) and designed according to the Colombian Earthquake Resistant Code (NSR-10) and with two design spectrums of the Bogota microzoning (2010). Using the frame models and generating random numbers of the steel and concrete mechanical properties (according to the statistic analyses of the laboratory test) 80,000 pushover analyses of 2D frames were performed to obtain the inelastic drift and its probability distribution functions for different damage levels (Montecarlo simulations). According to the results the average drifts limits for a yield damage level, immediate occupancy damage level and life safety damage level are 0,51%, 0,84% and 1,41% respective. [ABSTRACT FROM AUTHOR]

This paper presents a generalized strategy applied to perform the reduction of power distribution systems composed by several tapped feeders into equivalent radial feeders, as basic procedure required to the generalized implementation of impedance based fault location methods. The proposed strategy is tested using a fault location method, where it is shown a straightforward procedure to analyze the locations, and additionally the results shows errors lower than 3.5 % in the distance estimation for single line to ground, phase to phase, three phase faults. These results confirm the validity of the proposal. [ABSTRACT FROM AUTHOR]

In this paper a method to solve the state estimation problem in electric systems applying combinatorial optimization is presented. Its objective is the study of measures with difficult detection errors, which affect the performance and quality of the results when a classic state estimator is used. Due to the mathematical complexity, sensibility indicators are deduced from the theory of leverage points used in the Chu-Beasley optimization algorithm with the purpose of reducing the computational effort and enhance the quality of the results. The proposed method is validated in a 30-node IEEE system. [ABSTRACT FROM AUTHOR]

Collinearity and the lack of overlap in the data are problems that affect inference based on the logistic regression model. Simulation was used to investigate how the estimators that deal with collinearity (iterative Ridge) are affected, along with separation in the data (Firth's, and Rousseeuw and Christmann's) or both problems (Shen and Gao's). These estimators were compared considering the scaled condition number of the estimated information matrix, the bias and the mean squared error. In each one of the four scenarios studied, formed by using two levels of collinearity and two sample sizes, three degrees of overlap were considered in the data. It was found that iterative Ridge and Shen and Gao's estimators have null conditioning, as well as smaller bias and mean square error. The degree of overlap and the level of collinearity strongly affect the bias and mean square error of the maximum likelihood, Firth's and Rousseeuw and Christmann's estimators. [ABSTRACT FROM AUTHOR]

In this work we have collected estimators of the population proportion through the use of auxiliary information under simple random sampling. We analyzed the main properties of these estimators. Theorethical properties suggest that the estimators with use of auxiliary information can outperform alternative methods, and the results derived from a Monte Carlo simulation study support this view. Has made an application on a population of Risk of Acidication in Lakes in the Northeastern states of the U.S. conducted by the Environmental Monitoring and Assessment Program of the US Environmental Protection Agency. In the application we have compared the different estimators each other with the standard stimators. [ABSTRACT FROM AUTHOR]

In the paper the results of the combined strategy formed by Robust Principal Component Analysis and CUR matrix decomposition are applied to a practical problem for adjusting a regression model by using Partial Least Squares (PLS). The conclusions concerning their advantages of such an approach as well information about the adjusted models are given. [ABSTRACT FROM AUTHOR]

The remittances sent by Mexican migrants in the USA are relevant for recipient household at least in two senses. First, they contribute to rise income, and therefore to diminish poverty level. Second, they also contribute to regional and local economic development via the multipliers generated by the increases of the demand and of the investment in productive activities. Nonetheless, there are several estimations of household remittances magnitude. This paper analyzes the methodologies of Banco de Mexico (Mexican central bank) and those of recognized researchers. There is no consensus regarding the amount of money transferred by Mexican migrants in the USA. Consequently, the positive effects upon the recipient economy may not be conclusive. [ABSTRACT FROM AUTHOR]

This article has the purpose of determine and analyze the factors that explain the labor competitiveness-measured in terms of labor productivity- of the manufacture industry located in the Northern border. With census information of 1994, 1999 and 2004, a panel model with fixed effects was estimated, in which the labor competitiveness factors are considered, such as foreign direct investment, average remunerations, fixed capital investment and average firm size. The results show that all variables are significant determinants of labor competitiveness, however not all coefficients have a positive effect-as it was expected- upon competitiveness. [ABSTRACT FROM AUTHOR]

In recent years, the use of optical (Optical Backscatter Sensor, OBS) and acoustic (Acoustic Current Doppler Profiler, ADCP) instruments has allowed monitoring the temporal and spatial variation of the suspended sediment concentration (SSC) in coastal and estuarine environments with greater resolution. However, the development of the application of those techniques in tropical environments is incipient. For this study, an OBS-3A calibration procedure was implemented, taking dry and desegregated sediment from the study zone as a calibrating pattern. Moreover, we present the corrections required for the ADCP signal to be useful in the estimation of SSC due to geometrical spreading, the attenuation of sound by water, and the particles in suspension. The ADCP and OBS-3A were used to measure SSC in the Mira River delta system (Morro Island and principal river mouth), located on the Pacific coast of Colombia, a coastal tropical environment where some oceanographic and estuarine factors determine the signal response of the instruments. [ABSTRACT FROM AUTHOR]

The assessment of accuracy in binary classification tools must take into account two non-independent rates: true positives and false positives. A variety of indices have been proposed. They have been estimated for tests employed for early detection or screening purposes. We summarize and review the main methods proposed for performing a meta-analysis that assesses the accuracy of this type of tools. They are applied to the results from 14 studies that report estimates of the accuracy of the AUDIT. The method of direct aggregation does not allow the use of meta-analytic procedures; the separate estimation of sensitivity and specificity does not acknowledge that they are not independent; the SROC method treats accuracy and threshold as fixed effects and has limitations to deal with the potential role of covariates. The Normal Bivariate (NB) model and the Hierarchical Summary ROC (HSROC) model are statistically rigorous and can deal with the covariates properly. They allowed analyzing the association between the gender composition of the sample and the way the test AUDIT behaves in the example. [ABSTRACT FROM AUTHOR]

One of the most surprising capacities of the haptic system is the ability to estimate different properties of objects, like weight or length, through invariants of rotational mechanics that are accessible via the proprioceptive system. This field of research is called Dynamic Touch. In its classical experimental paradigm, the participant firmly grasps a rod that can be wielded but not seen, and he or she tries to match the hand-held rod's length using another rod that can be seen but not wielded. In the experiment reported here, we focus on the role of the exploratory behavior, restricting the wielding in six conditions that vary both the amplitude and the frequency of movements. Increments in the speed of the movement are shown to increase the accuracy in the haptic estimation. It is argued that these results support the moment of inertia as the best informational candidate, given that it is an invariant property that only emerges when rotational torques are applied. Alternative candidates such as static moment or mass are discarded because they do not depend on differential movements. [ABSTRACT FROM AUTHOR]

To date, Colombia lacks a sufficiently developed commodity market that allows estimating prices of agricultural commodity futures. Nonetheless, it is possible to estimate price bands within which they are likely to oscillate if certain no-arbitrage conditions are fulfilled. Based on the work of Díaz and Venegas, convenience yields are further incorporated, thus allowing the evaluation of eventual government policies and other market factors on the price of future contracts. The applicability of this new model is shown with an example regarding palm oil. This methodology can be applied to any other similar market. [ABSTRACT FROM AUTHOR]

The present work's objective to analyze what has been done on public budgets from a gender perspective at the federal level in Mexico and what are the prospects in this regard. It seeks to highlight the progress, reflecting on the challenges and outline some ideas on how to advance implementation of these budgets considering the peculiarities of mexican budget. Regarding the latter issue, we propose to use the budget analysis, understanding such analysis not as the accounting review of spending programs and revenue for a given fiscal year, but as the examination of a series of stages, not linear, allow to understand the institutional network in Mexico to manage and estimate its income and expenses. [ABSTRACT FROM AUTHOR]

A collaborative strategy for fault location in power distribution systems based on the fault impedance and the system signature, and using only single-end measurements, is presented in this paper. This strategy is useful to solve the multiple estimation of the faulted node, which is due to the presence of several laterals in the power system topology. According to the tests performed in a prototype power distribution system, considering single phase faults, phase to phase faults and three phase faults, and also using fault resistances from 0 to 40 Ω, the obtained results show an average absolute error of 5,2% approximately. From the results can be concluded that this proposal is efficient to locate faults in power distribution systems. [ABSTRACT FROM AUTHOR]

Objective. To introduce the Hospital Standardized Mortality Ratio (HSMR) as an alternative to assess the quality of hospital care in Mexico. Material and Methods. Datasets of public hospital discharges were used as source of information. The analyses were based in a logistic model to estimate the risk of hospital death adjusting by sex, age, length of stay and main diagnosis. The HSMR is estimated dividing the observed deaths by the addition of the risk for each discharge by hospital. Results. The ISSSTE had the lowest HSMR. At state level, the best figure was obtained by the hospitals of the ISSSTE in Veracruz, while the worst performance corresponds to hospitals of the SS in Nayarit. Conclusion. Our results suggest that this indicator can be used as a suitable alternative to evaluate the performance of hospitals in terms of mortality. [ABSTRACT FROM AUTHOR]