Análisis del papel de la familia en la supervivencia de los micronegocios en la ciudad de México

En este trabajo se propone analizar la actividad laboral de los integrantes de diversos núcleos familiares en pequeños establecimientos en la ciudad de México, y las repercusiones que su trabajo tiene sobre la vida familiar, así como el impacto de la dinámica familiar en las actividades laborales. Bajo esta perspectiva, el estudio busca aportar elementos que permitan dar respuestas a la siguiente inquietud: ¿la participación laboral de los miembros de la familia en el pequeño establecimiento y las relaciones que entre ellos se establecen, constituyen una forma de producción que permite asegurar la reproducción, tanto de la unidad económica como del consumo y el abastecimiento de la unidad familiar? Se intenta vincular la teoría con la investigación empírica sobre el lugar de la producción y de la reproducción, mediante el análisis de entrevistas en profundidad realizadas a propietarios y propietarias de micronegocios en la ciudad de México

Inference on an heterocedastic Gompertz tumor growth model

We consider a non homogeneous Gompertz diffusion process whose parameters are modified by generally time-dependent exogenous factors included in the infinitesimal moments. The proposed model is able to describe tumor dynamics under the effect of anti-proliferative and/or cell death-induced therapies. We assume that such therapies can modify also the infinitesimal variance of the diffusion process. An estimation procedure, based on a control group and two treated groups, is proposed to infer the model by estimating the constant parameters and the time-dependent terms. Moreover, several concatenated hypothesis tests are considered in order to confirm or reject the need to include time-dependent functions in the infinitesimal moments. Simulations are provided to evaluate the efficiency of the suggested procedures and to validate the testing hypothesis. Finally, an application to real data is considered

A hyperbolastic type-I diffusion process: Parameter estimation by means of the firefly algorithm

A stochastic diffusion process, whose mean function is a hyperbolastic curve of type I, is presented. The main characteristics of the process are studied and the problem of maximum likelihood estimation for the parameters of the process is considered. To this end, the firefly metaheuristic optimization algorithm is applied after bounding the parametric space by a stagewise procedure. Some examples based on simulated sample paths and real data illustrate this development

Two Stochastic Differential Equations for Modeling Oscillabolastic-Type Behavior

Stochastic models based on deterministic ones play an important role in the description of growth phenomena. In particular, models showing oscillatory behavior are suitable for modeling phenomena in several application areas, among which the field of biomedicine stands out. The oscillabolastic growth curve is an example of such oscillatory models. In this work, two stochastic models based on diffusion processes related to the oscillabolastic curve are proposed. Each of them is the solution of a stochastic differential equation obtained by modifying, in a different way, the original ordinary differential equation giving rise to the curve. After obtaining the distributions of the processes, the problem of estimating the parameters is analyzed by means of the maximum likelihood method. Due to the parametric structure of the processes, the resulting systems of equations are quite complex and require numerical methods for their resolution. The problem of obtaining initial solutions is addressed and a strategy is established for this purpose. Finally, a simulation study is carried out.This work was supported in part by the Ministerio de Economía, Industria y Competitividad, Spain, under Grant MTM2017-85568-P and by the Consejería de Economía y Conocimiento de la Junta de Andalucía, Spain under Grant A-FQM-456-UGR18

Remesas femeninas y hogares en el estado de Guanajuato

El propósito de este artículo es analizar las remesas monetarias que envían las mujeres guanajuatenses emigradas a sus familiares que permanecen en sus comunidades de origen y, haciendo uso de estadística descriptiva, examinar las características de los hogares receptores, distinguiendo las remesas femeninas y masculinas, así como determinar los montos, frecuencias y usos de estos recursos. Finalmente, se reflexiona sobre los factores asociados a la recepción de las remesas femeninas en el estado de Guanajuato, tratando de identificar diferencias entre los hogares receptores según el género del remitente

T-Growth Stochastic Model: Simulation and Inference via Metaheuristic Algorithms

The main objective of this work is to introduce a stochastic model associated with the one described by the T-growth curve, which is in turn a modification of the logistic curve. By conveniently reformulating the T curve, it may be obtained as a solution to a linear differential equation. This greatly simplifies the mathematical treatment of the model and allows a diffusion process to be defined, which is derived from the non-homogeneous lognormal diffusion process, whose mean function is a T curve. This allows the phenomenon under study to be viewed in a dynamic way. In these pages, the distribution of the process is obtained, as are its main characteristics. The maximum likelihood estimation procedure is carried out by optimization via metaheuristic algorithms. Thanks to an exhaustive study of the curve, a strategy is obtained to bound the parametric space, which is a requirement for the application of various swarm-based metaheuristic algorithms. A simulation study is presented to show the validity of the bounding procedure and an example based on real data is provided.Ministerio de Economía, Industria y Competitividad, Spain, under Grant MTM2017-85568-PFEDER/Junta de Andalucía-Consejería de Economía y Conocimiento, Spain, Grant A-FQM-456-UGR1

Statistical analysis and first-passage-time applications of a lognormal diffusion process with multi-sigmoidal logistic mean

We consider a lognormal diffusion process having a multisigmoidal logistic mean, useful to model the evolution of a population which reaches the maximum level of the growth after many stages. Referring to the problem of statistical inference, two procedures to find the maximum likelihood estimates of the unknown parameters are described. One is based on the resolution of the system of the critical points of the likelihood function, and the other is on the maximization of the likelihood function with the simulated annealing algorithm. A simulation study to validate the described strategies for finding the estimates is also presented, with a real application to epidemiological data. Special attention is also devoted to the first-passage-time problem of the considered diffusion process through a fixed boundary.Universita degli Studi di Salerno within the CRUI-CARE Agreemen

Persistencias y cambios en la participación laboral en el Estado de México durante el periodo 2000-2012

En el Estado de México, entre 2000 y 2010, se observan algunas diferencias en las características de la participación laboral de hombres y mujeres, fundamentalmente cambios en el sector económico, en la ocupación y en la región. Teniendo en cuenta que la tasa general de ocupación en el Estado de México mostró su mayor capacidad de absorción de mano de obra durante los años 2000 (96.7) y 2002 (97.3) y la menor hacia el final del periodo (2009: 92.6 y 2010: 93.2 ENOE, 2009 y 2010), interesa analizar cómo han participado diferencialmente hombres y mujeres, y cómo varía dicha participación en las relaciones considerando como dimensiones centrales del análisis el nivel de ingresos, la ocupación, el sector, la edad, el estado civil y por supuesto la perspectiva de género. Además, interesa observar cómo se comportan estos cambios en las diferentes regiones del estado (16 regiones, según la regionalización del gobierno del estado), considerando que una parte de éstas (58 municipios de cinco regiones) están conurbados con el Distrito Federal. La consolidación ocupacional de los municipios conurbados y no conurbados, en referencia a los dos años censales considerados aportan algunas particularidades en los mercados laborales locales que vale la pena identificar y analizar

Some Notes about Inference for the Lognormal Diffusion Process with Exogenous Factors

Different versions of the lognormal diffusion process with exogenous factors have been used in recent years to model and study the behavior of phenomena following a given growth curve. In each case considered, the estimation of the model has been addressed, generally by maximum likelihood (ML), as has been the study of several characteristics associated with the type of curve considered. For this process, a unified version of the ML estimation problem is presented, including how to obtain estimation errors and asymptotic confidence intervals for parametric functions when no explicit expression is available for the estimators of the parameters of the model. The Gompertz-type diffusion process is used here to illustrate the application of the methodology.This work was supported in part by the Ministerio de Economía, Industria y Competitividad, Spain, under Grants MTM2014-58061-P and MTM2017-85568-P