Análisis de los fondos de pensiones obligatorias en el desarrollo y evolución del sistema financiero colombiano

El presente trabajo tiene como objetivo principal analizar la función que tienen los fondos de pensiones en el desarrollo y la evolución del mercado de capitales colombiano, como agentes directos en la gestión de inversión de los diferentes activos tranzados en él, con el fin de ayudar al dinamismo y la estabilidad de la economía en desarrollo del país. Se inicia con un breve recuento de lo que es el sistema pensional en Colombia, en el que se mencionan su evolución y el viraje que tuvo a partir de la promulgación de la ley 1328 de 2009, que permitió crear los multifondos. En seguida se analiza el crecimiento que ellos tuvieron desde el año 2009 hasta mayo del 2019 en paralelo con la evolución del mercado de capitales. Por último, se examinan las principales reformas tributarias que tuvieron incidencia sobre los fondos y su contribución a la generación de ahorro e inversión.The following work has as main objective to carry out an analysis of the role that pension funds have in the development and evolution of the Colombian capital market, as direct agents in the investment management of the different assets traded therein, helping the dynamism and Stability of our developing economy. It will begin with a brief account of what the pension system is in Colombia, mentioning its evolution and the turn it had since the creation of Law 1328 of 2009 that allowed the creation of Multifunds. Subsequently, the growth they had from 2009 to May 2019 is analyzed in parallel with the evolution of the capital market. Finally, the main tax reforms that had an impact on the funds and their contribution to the generation of savings and investment will be examined

Mexican-origin parent and child reported neighborhood factors and youth substance use

BackgroundStructural oppression affects health behaviors through residence in suboptimal neighborhoods and exposure to community violence. Youth and parents report perceptions of neighborhood factors that can affect youth substance use behaviors. Given that Latinx youth report higher levels of perceived community violence than other racial and ethnic groups, it is imperative to examine how youth- and parent-perceived neighborhood-level factors may relate to youth substance use.MethodsData were collected using clinical interviews with family triads (fathers, mothers, and youth) and parent–child dyads (father or mother and youth) enrolled in the Seguimos Avanzando study of 344 Mexican-origin families in Indiana. Neighborhood measures, including perceptions of exposure to violence, neighborhood characteristics, and neighborhood collective efficacy, were included in parent and youth surveys. Self-report measures for past year alcohol and drug use were included in the youth survey only. T-tests were conducted to estimate differences in neighborhood reports among the sample triads. A series of linear regression models were used to estimate the associations between youth-, mother-, and father-reported perceptions of neighborhood factors and youth substance use.ResultsPreliminary results indicate that fathers reported higher levels of exposure to violence than mothers [t(163) = 2.33, p = 0.02] and youth [t(173) = 3.61, p < 0.001]. Youth reported lower negative neighborhood characteristics than mothers [t(329) = 6.43, p < 0.001] and fathers [t(169) = 3.73, p < 0.001]. Youth reported significantly better neighborhood collective efficacy than mothers [t(296) = 3.14, p = 0.002], but not statistically different from fathers. Results from the primary analysis showed that youth exposure to violence was positively associated with youth substance use (b = 0.24, SE = 0.06, p < 0.0001), but the youth’s neighborhood characteristics and collective efficacy were not significantly associated with youth substance use. None of the parent-reported neighborhood variables were associated with youth substance use.ConclusionThe discrepant findings between parent and youth reports of perceived neighborhood characteristics and substance use have important implications for researchers and community stakeholders, and for developing targeted interventions and prevention strategies. Our study highlights the need to address youth experience of community violence and to prioritize creating safe and inclusive neighborhood environments. Potential strategies include improving community resources, strengthening social support networks, promoting open communication about neighborhood risks, and fostering collaborative efforts to address substance use behaviors

Mechanisms of aggregate formation in highly-filled simplified industrial nanocomposites

International audienceNanocomposites made of hard inorganic nanoparticles (NPs) embedded in a soft polymer matrix may have rheological properties of interest for various applications, and in particular car tires. These properties depend crucially on the dispersion of the filler NPs, which has been studied in simplified industrial (i.e., without crosslinker and related chemistry) styrene–butadiene nanocomposites with silica filler NPs. We have developed a quantitative structural analysis based on a combination of electron microscopy, Monte Carlo simulations, and small-angle X-ray scattering. It allowed us to establish a global structural model, where primary silica beads are organized within small aggregates, which themselves fill large-scale fractal branches. Experimental parameters have been varied independently, starting with the silica volume fraction si, the matrix composition (percentage of graftable chains), and the chain mass. The grafting density on the silica NPs was shown to be the structure- and rheology-determining parameter, and we will show that a simple mechanism is able to explain the evolution of aggregate size and mass with grafting density. Moreover, dynamical properties have been followed by broadband dielectric spectroscopy (BDS) recently, and the detailed characterization of two high-temperature silica-related processes provided evidence that one of them can be linked to the structural evolution of these nanocomposites. Our work thus suggests that such high-temperature BDS-measurements can be used to detect reorganizations in structurally complex silica nanocomposites.Baeza et al, Macromolecules 2013, ibid 2013, ACS Macro Letters 2014, Soft Matter 201