How hard is a commercial puzzle: the eternity II challenge

Recently, edge matching puzzles, an NP-complete problem, have received, thanks to money-prized contests, considerable attention from wide audiences. We consider these competitions not only a challenge for SAT/CSP solving techniques but also as an opportunity to showcase the advances in the SAT/CSP community to a general audience. This paper studies the NP-complete problem of edge matching puzzles focusing on providing generation models of problem instances of variable hardness and on its resolution through the application of SAT and CSP techniques. From the generation side, we also identify the phase transition phenomena for each model. As solving methods, we employ both; SAT solvers through the translation to a SAT formula, and two ad-hoc CSP solvers we have developed, with different levels of consistency, employing several generic and specialized heuristics. Finally, we conducted an extensive experimental investigation to identify the hardest generation models and the best performing solving techniques.

Edge matching puzzles as hard SAT/CSP benchmarks

Recently, edge matching puzzles, an NP-complete problem, have rececived, thanks to money-prized contests, considerable attention from wide audiences. We consider these competitions not only a challenge for SAT/CSP solving techniques but also as an opportunity to showcase the advances in the SAT/CSP community to a general audience. This paper studies the NP-complete problem of edge matching puzzles focusing on providing generation models of problem instances of variable hardness and on its resolution through the application of SAT and CSP techniques. From the generation side, we also identify the phase transition phenomena for each model. As solving methods, we employ both; SAT solvers through the translation to a SAT formula, and two ad-hoc CSP solvers we have developed, with different levels of consistency, employing several generic and specialized heuristics. Finally, we conducted an extensive experimental investigation to identify the hardest generation models and the best performing solving techniques.

Els Certàmens literaris a Barcelona, segles XIV-XVIII

Repàs de la història dels certàmens literaris a Barcelona fins a l’entrada de l’època contemporània, des del s. XIV fins al XVIII

Chromosomal polymorphism of D. subobscura: no differences between wild males and sons of wild females

When analyzing the chromosomal polymorphism of D. subobscura natural populations it is assumed that the information provided by wild males and sons of wild females is equivalent. Thus, using both in the analysis it is possible to increase the sample size. However, it is important to verify whether there are significant differences between both groups or not. The aim of this research has been to statistically compare the results of chromosomal polymorphism of both groups. We have used data from Avala Mountain (Serbia) where D. subobscura flies were collected from the 30th May to the 5th June 2011. Avala is located 18 km south of Belgrade and the trapping place is a forest with polydominant communities of Fagetum submontanum Table 1. Number and percentage of adult flies collected in Font Groga (Barcelona, Spain) on 9th October 2013. Males and sons of wild females were crossed with virgin females of the Küsnacht strain. Third instar larvae from F1 were dissected to obtain the salivary glands and the polytene chromosomes were stained and squashed in aceto-orcein solution. No significant differences were observed for any chromosome of the karyotype: A (p-value = 0.485), J (p-value = 0.230), U (p-value =0.572), E (p-value = 0.536), and O (p-value = 0.338). Thus, it seems that the two groups can be grouped together to obtain the chromosomal polymorphism of the population.

Concurs d'idees per a la reforma i ampliació del "Colegio de Arquitectos de Córdoba"

Award-winning

Inbreeding and thermal adaptation in Drosophila subobscura

Using a well-adapted Drosophila subobscura population (Avala, Serbia), a drastic experiment of inbreeding was carried out to assess whether the expected level of homozygosity could be reached or if other evolutionary forces affected the process. In general, no significant changes of inversion (or arrangement) frequencies were detected after 12 brother sister mating generations. Furthermore, no significant differences were obtained between observed and expected (under the inbreeding model) karyotypic frequencies. Thus, these results seemed to indicate that the main evolutionary factor in the experiment was inbreeding. However, in the G12 generation, complete chromosomal fixation was reached only in two out of the eight final inbred lines. In these lines, the chromosomal compositions were difficult to interpret, but they could be likely a consequence of adaptation to particular laboratory conditions (constant 18 °C, food, light period, etc.). Finally, in a second experiment, the inbred lines presented higher fertility at 18 °C than at 13 °C. Also, there was a significant line effect on fertility: inbred line number 6 (A1, J1, U1+2; U1+2+6, E8, and O3+4+7) presented the highest values, which maybe the result of an adaptation to laboratory conditions. Thus, the results obtained in our experiments reflect the adaptive potential of D. subobscura inversions.

ARGUE

Award-winning

Willkommen: concurs de millora de Dalt la Costa de Ses Voltes de Maó

Award-winning

Innovación y Aprendizaje: un nuevo modelo para la formación universitaria: ¿Por qué y para qué? = Innovation and Learning: a New Model for University Education: Why and for What?

The legislative reforms in university matters driven in recent years, beyond the provoked controversies, offer to universities the possibility to develop a new model in line with the European environment, focusing on quality aims and adapting to the socioeconomic current challenges. A new educational model centered on the student, on the formation of specific and transverse competitions, on the improvement of the employability and the access to the labor market, on the attraction and fixation of talent, is an indispensable condition for the effective social mobility and for the homogeneous development of a more responsible and sustainable socioeconomic and productive model