Coordinating visualizations of polysemous action: Values added for grounding proportion

We contribute to research on visualization as an epistemic learning tool by inquiring into the didactical potential of having students visualize one phenomenon in accord with two different partial meanings of the same concept. 22 Grade 4-6 students participated in a design study that investigated the emergence of proportional-equivalence notions from mediated perceptuomotor schemas. Working as individuals or pairs in tutorial clinical interviews, students solved non-symbolic interaction problems that utilized remote-sensing technology. Next, they used symbolic artifacts interpolated into the problem space as semiotic means to objectify in mathematical register a variety of both additive and multiplicative solution strategies. Finally, they reflected on tensions between these competing visualizations of the space. Micro-ethnographic analyses of episodes from three paradigmatic case studies suggest that students reconciled semiotic conflicts by generating heuristic logico-mathematical inferences that integrated competing meanings into cohesive conceptual networks. These inferences hinged on revisualizing additive elements multiplicatively. Implications are drawn for rethinking didactical design for proportions. © 2013 FIZ Karlsruhe

Exploring the link between employment search time and reservation wages in Southern Europe

In our piece of work we are facing a two-fold problem: on the one hand, we study the behaviour of job seekers and the extent to which reservation wages and unemployment benefits play a relevant role in the transition into working life. On the other hand, we intend to find out whether the determinants of the job search process may also affect subsequent wages.transiciones laborales, prestaciones por desempleo, salarios de reserva, ganancias,earnings, transitions into work, unemployment benefits, reservation wages.

Exploring the link between employment search time and reservation

In our piece of work we are facing a two-fold problem: on the one hand, we study the behaviour of young job seekers and the extent to which reservation wages and unemployment benefits play a relevant role in the transition into working life. On the other hand, we intend to find out whether the determinants of the job search process may also affect subsequent wages. We undertake an empirical approach combining one-step estimations with two-step instrumental variables techniques. The data used to this end come from the European Community Household Panel (ECHP) for the period 1995-2001. To be precise, the sub-sample gathers both male and female Southern European (Italian, Greek, Spanish and Portuguese) workers. From the results of the analysis important subtleties arise, particularly related to differences across countries.Transitions into work, unemployment benefits, reservation wages, earnings.

New relative indices of inequality base don the lorenz curve: perimeter and longitudinal ratio measures?

Empleando como fuente estadística la Memoria de la Administración Tributaria del año 2005, este trabajo presenta dos medidas alternativas de la medición de la desigualdad del ingreso en España.inequality, relative indices of inequality