Migración internacional y precariedad laboral. El caso de la industria de la construcción en Chile / International migration and labour precariousness. The case of the construction industry in Chile

La industria de la construcción ha experimentado en las últimas décadas importantes cambios a nivel de gestión del trabajo, condiciones laborales y composición de la fuerza de trabajo, destacando la creciente participación de trabajadores migrantes. El objetivo del presente artículo es analizar la relación entre la subcontratación en cuanto modelo de gestión, las condiciones laborales que devienen del tipo de contrato usualmente utilizado y la presencia de migrantes en las obras. Sostendremos que estos tres elementos, están estrechamente vinculados entre sí, determinando altos grados de precariedad en quienes trabajan en los últimos eslabones de la cadena de subcontratación. A partir de una metodología cualitativa basada en entrevistas realizadas en Santiago, Iquique y Antofagasta y observaciones participantes en obras en Santiago, este estudio revela que existe una relación entre la precariedad en las condiciones laborales y la creciente inclusión de trabajadores migrantes, cuya vulnerabilidad resulta conveniente para este modelo económico.(AU)

In recent decades, the construction industry has undergone significant changes in labour management, working conditions and workforce composition, with a significant increase on the recruitment of migrant workers. The aim of this paper is to analyze the relationship between subcontracting as a management model, the working conditions that prevail within the type of contract commonly used, and the presence of migrants in the construction industry. We argue that these three elements that characterize the construction industry are closely related. Based on a qualitative methodological approach that consisted of interviews conducted in Santiago, Iquique and Antofagasta, as well as participant observations in the construction field in Santiago, this study reveals that the precariousness in the working conditions is related to the increased recruitment of migrant workers, whose vulnerability becomes suitable for such an economic model.(AU)

Safety evaluation and nutritional composition of a Fraxinus excelsior seed extract, FraxiPure™.

A natural extract obtained from the seeds of Fraxinus excelsior L. (FraxiPure™) has been previously reported to reduce glycemia in animal models and in humans. The objective of this work was to evaluate the safety of FraxiPure™ at in vitro, in vivo and human levels. In addition, nutritional analyses revealed an extract high in carbohydrates, with minor levels of protein, dietary fiber, glucose and sucrose. IC(50) and IC(90) values of 1.447 and 2.530 mg/mL, respectively, after 72 h incubation were calculated using the MTT assay. FraxiPure™ conferred a magnitude of protection of 69.2% against the formation of micronuclei in irradiated human lymphocytes as determined by the micronucleus assay. An LD(50) of greater than 2500 mg/kg was concluded following an acute oral toxicity study in Sprague-Dawley rats. A human safety evaluation in a double-blind, placebo-controlled parallel study of 100 healthy volunteers revealed no significant differences between daily consumption of 1000 mg of FraxiPure™ for 90 days and placebo (maltodextrin) for any of the biochemical or hematological parameters studied. Numbers of adverse events were similar in both groups, and were deemed mild to moderate. These results demonstrate, for the first time, the safety and tolerability of FraxiPure™ for consumption in healthy subjects.

Pure silica ITQ-32 zeolite allows separation of linear olefins from paraffins.

ITQ-32 is able to separate propene from propane and represents a clear improvement with respect to previous zeolites in achieving the separation of trans-2-butene and 1-butene from the C(4) fraction using only one zeolite.

Synthesis and structure of the bidimensional zeolite ITQ-32 with small and large pores.

A new bidimensional zeolite containing 8R and 12R pores, denoted as ITQ-32, has been synthesized and its structure solved from powder X-ray diffraction data. This zeolite presents a relatively large pore volume (0.16 cm3/g) and pore apertures of 3.5 x 4.3 A and can be prepared as a nearly pure silica zeolite and as aluminosilicate. In the latest case, acidic properties are developed.

Toxocariasis humana en Chile: evaluación del diagnóstico serológico mediante ELISA / Human toxocariasis in Chile: evaluation of ELISA for diagnosis

Mediante ELISA y utilizando antígeno larval somático de toxocara canis se procesaron los sueros de 138 personas: 50 controles sanos, 42 pacientes sospechosos de LMO, 30 de LMV y 16 con otras infecciones. Se observó títulos significativamente mayores en los pacientes sospechosos de LMV (promedio 1: 64) que en los otros grupos: sanos (promedio 1: 8) y LMO (promedio 1: 16). No hubo reactividad cruzada de importancia con otras infecciones, y el título diagnóstico que se sugiere para LMV es 1: 64. El método empleado parece ser muy poco sensible para el diagnóstico de LMO. Se concluye que ELISA es útil en nuestro país para el diagnóstico de LMV, pero no parece confiable para el de LMO. Los resultados de esta técnica serológica deben interpretarse cuidadosamente a la luz de los hallazgos clínicos de los pacientes