Abstract
In this paper, we analyse the effect of using appropriate tie breaking criteria in dispatch rules. We consider four different dispatch procedures, and for each of these heuristics we compare two versions that differ only in the way ties are broken. The first version breaks ties randomly, while the second uses a criterion that incorporates problem-specific knowledge. The computational results show that using adequate tie breaking criteria improves the performance of the dispatch heuristics. The magnitude of the improvement is different for the four heuristics, and also depends on the characteristics of each specific instance. The use of problem-related knowledge for breaking ties should therefore be given some consideration in the implementation of dispatch rules.

Abstract
We present a general methodology to model the behavior of heuristics for the Job-Shop Scheduling (JSS) that address the problem by solving conflicts between different operations on the same machine. Our models estimate the gaps between consecutive operations on a machine given measures that characteristics the JSS instance and those operations. These models can be used for a better understanding of the behavior of the heuristics as well as to estimate the performance of the methods. We tested it using two well know heuristics: Shortest Processing Time and Longest Processing Time, that were tested on a large number of random JSS instances. Our results show that it is possible to predict the value of the gaps between consecutive operations from on the job, on random instances. However, the prediction the relative performance of the two heuristics based on those estimates is not successful. Concerning the main goal of this work, we show that the models provide interesting information about the behavior of the heuristics.

Abstract
By combining features from distinct theoretical approaches, namely the evolutionary and the job search, matching and bargaining literatures, we propose a model that captures the main dynamics of a world where heterogeneous firms and workers interact and co-evolve. Within a micro-meso framework, the model focuses on the influence of firms' labour choices ("institutional settings") on industry dynamics, taking into account the existence of employment adjustment costs. The consideration of endogenous matching and bargaining processes in the labour market results in significant frictions, such as the simultaneous coexistence of unfilled job vacancies and unemployment. In a setting where technological progress is not biased a stylized fact of industrialized world economies in the last few decades emerges, the increasing wage inequality. Additionally, turbulence in the industry increases after a negative demand shock. As expected, the negative demand shock causes a decrease in the number of vacancies and, consequently, unemployment rates increase considerably. Interestingly, and mimicking the recent experiences of countries such as US, Spain, Greece and Portugal, the rise in unemployment is matched by a rise in contractual wages. This outcome is explained by the lower ability of the firms to fill their posted vacancies, which results from friction in the interactions among agents.