Informal Referrals, Employment and Wages: Seeking Causal Directions

Employers and job seekers rely extensively on job informational networks to fill vacancies or to find a job. The widespread use of job contacts to find work has been largely associated with labor outcomes, such as finding a job or even affecting wages. Some scholars have claimed that informal referrals play a determinant role in reducing informational mismatches between potential employers and job seekers. Although several studies have shown that the use of friends and relatives is correlated with labor outcomes, little is known about the causal effect. In this article, I aim to identify whether there is a causal effect of using informal referrals on two main outcomes: the probability of being employed and hourly wages. I use a large data set from Colombia, the Living Standard Survey 2003, to contrast the results from three main methodologies: standard OLS estimation, propensity-score matching, and instrumental variables. Results suggest that much of the positive effect of using informal referrals on employment reflects the prevalence of informal-sector jobs to be filled through this method rather than a causal effect. On the contrary, the results for hourly wages suggest a negative causal effect of using job informational networks, which is explained by the low-quality/poor matches theory. Yet, this is only true in formal-sector firms.informal referrals, job search methods, employment rates, hourly wages, selec- tion bias, OLS, Propensity-Score Matching, Instrumental Variables, Roy Model

The Employment Advantages of Skilled Urban Areas

This paper explores whether the agglomeration of human capital leads to social employment advantages in urban labor markets of a developing country: Colombia. I estimate the social effects of human capital agglomeration by comparing employment opportunities of individuals located in urban areas in which the level of education differs. Results show that employment opportunities are higher on average in skilled urban areas. Three explanations have been offered: human capital externalities, production complementarities, and consumption spillovers. To distinguish between them, I analyze the effect of an increase on the college share on the employment rate for different education groups. Spatial employment differences in Colombia are mostly explained by human capital externalities and production complementarities.local labor markets, employment, human capital externalities, production complementarities, consumer demand spillovers, signaling, congestion

Spatial Unemployment Differentials in Colombia

This paper studies the geographic distribution of unemployment rates in Colombian urban areas. It introduces measures of spatial correlation and spatial econometric techniques to analyze the dependence in local unemployment rates across municipalities. Results suggest that Colombian municipalities have experienced a polarization process between 1993 and 2005, as municipalities' unemployment rates have followed different evolutions relative to the National average. This process has been accompanied by the creation of unemployment clusters, that is to say, municipalities had very similar unemployment outcomes to those of their neighbors. This analysis uses a spatial Durbin model to explore the influence of various factors in determining differences in regional unemployment rates. According to our findings differences in labor demand, immigration rates, and urbanization are factors behind observed municipal unemployment disparities.local labor markets, unemployment di erential, polarization, clustering, spatial econometrics, spatial Durbin model

Teacher education pedagogies and methodological constructs: or about different ways to approach teacher education

This paper plots the methodological constructs identified in different teacher education pedagogies deployed in teacher education settings of Higher Education Institutes in the province of Catamarca. The focus is on showcasing how future teachers are aided -from the methodological constructs of mentors- to make pedagogical decisions and broaden their potential for action during the educational path. The research was conducted from a qualitative approach. Three Higher Education Institutes representing different socio-cultural contexts and educational traditions were selected on the assumption that distinct pedagogies would be found; not only structured on the basis of stereotypical training, but also on the specificity of the disciplinary field. Seventeen semi-structured interviews were carried out and were accompanied by classroom observation of teacher educators in different areas, from distinct disciplinary backgrounds and varied seniority. The qualitative analysis of the data enabled the reconstruction of three typologies that explain the modes in which teacher education is pedagogically configured in the institutes under study as well as the dominant methodological construct that sets up each pedagogical approach. Thus, the pedagogy of ‘modeling’ teaching is based on methodological constructs based on the transmission of disciplinary contents and the instilment of behavior patterns; the ‘traditional’ view is built on methodological constructs elaborated on the basis of disciplinary logic; and the ‘eclectic’ approach is materialized in methodological constructs based on the synthesis of heterogeneous components or constructions grounded on pedagogical abstention.Fil: Diaz, Ana Griselda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; ArgentinaFil: Yuni, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; Argentin

Cuantificación de las poblaciones leucocitarias en tejido adiposo de ratones BALB/c suplementados con edulcorantes comerciales

Se ha evidenciado como principales contribuyentes a la creciente epidemia de obesidad, al exceso de consumo de alimentos energéticamente densos y la reducción de la actividad física, entre las medidas de prevención y tratamiento se considera la implementación de edulcorantes no calóricos para este propósito. Objetivos: Caracterizar poblaciones leucocitarias del tejido adiposo gonadal de ratones consumidores de edulcorantes comerciales, y cuantificar las poblaciones leucocitarias de: linfocitos T (CD3+) y sus subpoblaciones CD4 y CD8, macrófagos (CD14+) y linfocitos B (CD19+) con marcadores de superficie MHC I, MHC II. Metodología: Se trabajó con tejido adiposo de ratones BALB/c de 14 semanas de edad, machos y hembras, suplementados con edulcorantes comerciales durante 6 semanas y clasificados en grupos de 6 ratones por edulcorante (sucralosa, estevia, sacarosa y control, por sexo). Se obtuvo el tejido adiposo gonadal y se cuantificaron las diferentes poblaciones celulares y los marcadores de superficie MHC-I y MHC-II empleando la técnica de citometría de flujo. Resultados: El aumento de peso en los grupos de tratamiento fue significativamente mayor que el grupo control, el consumo de edulcorantes fue mayor en el grupo sacarosa hembras (40 mL/semana) y machos (47.3 mL/semana), mientras que el consumo de alimento fue mayor en el grupo sucralosa hembras (27.4 g/semana) y machos (32.1g/semana). Se manifestó un incremento en la frecuencia de células CD45+ en hembras con sucralosa 66.1 ± 3.4%), estevia (63.8 ± 5.0%) y sacarosa (67.7 ± 4.9%) en contraste con ratones macho las diferencias se encontraron en sacarosa (68.4 ± 6.0%) y estevia (67.1 ± 3.4%). Para el marcador CD14+ los datos muestran que los grupos de hembras con sacarosa (21.3 ± 4.3%) y sucralosa (22.2 ± 3.3%) presentan una frecuencia mayor de células, los ratones machos muestran diferencias en el grupo sacarosa (19.6 ± 1.4%). El análisis de la frecuencia de células CD19+ en hembras muestra diferencias en sucralosa (69.4 ± 5.7%), los resultados en ratones macho mostraron diferencia en los grupos sacarosa (38.1 ± 2.6%) y estevia (36.8 ± 4.1%). Conclusiones: El consumo crónico de edulcorantes artificiales puede tener efectos en las modificaciones de las poblaciones de leucocitos totales, macrófagos y linfocitos B en el tejido adiposoConsejo Mexiquense de Ciencia y Tecnologí

Integrated strategies for analyzing the environmental impact of energy conversion systems

La comunità scientifica internazionale è ormai concorde nell’attribuire gran parte della responsabilità per il riscaldamento globale alle emissioni antropogeniche di CO2, causate principalmente dalla combustione di carburanti fossili nei sistemi per la produzione di energia. Le scelte industriali e politiche in merito alle fonti primarie di energia sono guidate da considerazioni di carattere fondamentalmente economico, il che spiega come mai il carbone resti il combustibile più usato, pur essendo quello a maggior impatto ambientale, e quanto poco spazio abbiano le fonti energetiche alternative. La tesi si propone di studiare metodologie per la riduzione delle emissioni di CO2, limitatamente ai sistemi per la produzione di energia, fornendo indicatori sulle prestazioni degli impianti che integrano tre dimensioni del sistema: termodinamica, economica, ambientale. Dopo aver esaminato le caratteristiche degli approcci economici e regolamentatori, si concentra l’attenzione sui metodi più ingegneristici, per poi porre la necessità di un approccio multidimensionale alla tematica. Discussi ed esaminati gli strumenti metodologici più evoluti nell’analisi multioggetto, si propongono due metodologie originali, d’impostazione tecnica ed olistica, rispettivamente, con le quali si sviluppano funzioni aggregate per l’analisi dei sistemi energetici, applicate successivamente per confrontare due tipi di impianti

Protective Effect of Modified Human Fibroblast Growth Factor on Diabetic Nephropathy

Oxidative stress is a key mechanism causing Diabetic Nephropathy (DN). Acidic fibroblast growth factor (aFGF) is known to confer protection from oxidative stress. However, it also has significant angiogenic activity. Hence, we have generated a mutated human acidic FGF (maFGF), with intact antioxidant properties but devoid of angiogenic activities. Recent evidence shows that maFGF treatment prevented diabetic cardiomyopathy and further in vitro studies suggest that this prevention is mediated by suppression of cardiac oxidative stress, hypertrophy and fibrosis. We hypothesized that maFGF treatment has a protective effect in DN. We show that maFGF treatment did not affect body weight and blood sugar levels in a type 1 diabetic mouse model. However maFGF prevented renal functional alterations in diabetes and decreased renal hypertrophy following long-term diabetes. maFGF also prevented diabetes–induced DNA damage, upregulation of angiotensinogen, oxidative stress marker heme oxygenase 1, and alteration of endothelial nitric oxide synthase (eNOS). Surprisingly, it failed to prevent upregulation of the fibrogenic cytokine transforming growth factor β1 mRNA expression. However, long term administration of maFGF partially prevented diabetes-induced extracellular matrix proteins accumulation. Further analyses showed similar results in high glucose-induced alterations in podocytes and microvascular endothelial cells. Likewise, maFGF showed prevention of diabetes- induced decreased nitric oxide (NO) production and apoptosis in vivo and in vitro. These results were consistent with the prevention of long term diabetes- induced down regulation of eNOS enzyme. Data from these experiments suggest that the preventative effects of maFGF treatment in DN are probably via alteration of NO production, and indicate a potential therapeutic role of maFGF in DN