The Dynamics of Perspective in Quantum Physics: An Analysis in the Context of Teacher Education

Debates on the philosophical interpretations of quantum physics have motivated a renewed interest in how secondary and lower undergraduate students interpret quantum phenomena. In an attempt to contribute to this effort, this paper examines the dynamics of perspec tive in quantum physics in the context of teacher education. The goal of the study is to investigate how students (N = 36) from a Master's Degree in Secondary Education Teacher Training in Spain negotiate perspective as they participate in small-group discussions of quantum physics topics. This study focuses on the wave-particle duality, superposition of states, and the calculation of probabilities for two-state systems. The method of research is grounded in sociocultural discourse analysis and focuses on the properties of the utter ance as outlined by Bakhtin. Analysis shows that the subjects of the study adopt multiple perspectives when representing the referents of quantum theory. We also find that students' perspective change is usually followed by a change in the referentially semantic content. Finally, it is suggested that some perspectives are more appropriate than others depending on the task at hand and the learning goals previously defined for instruction

An exact algorithm for the mixed-model level scheduling problem

The Monden Problem, also known as the Output Rate Variation Problem, is one of the original formulations for mixed-model assembly line-level scheduling problems in a just-in-time system. In this paper, we develop a new branch-and-bound procedure for the problem that uses several new and previously proposed lower and upper bounds. The algorithm also includes several dominance rules that leverage the symmetry in the problem as well as a new labelling procedure that avoids repeated exploration of previously examined partial solutions. The branching strategy exploits the capabilities of current multiprocessor computers by exploring the search tree in a parallel fashion. The algorithm has been tested on several sets of instances from the literature and is able to optimally solve problems that are double the size of those addressed by other procedures previously reported in the literature.Preprin

Equilibrado de la línea de montaje del motor del modelo Pathfinder en la planta de NISSAN de Barcelona

Postprint (published version

Allocating refuse bins for selective waste collection, a case study

One of the problems found in Municipal Waste Management is the allocation of refuse bins to different collection areas where waste (glass, paper, plastic, organic material) is left by the citizens. The relationship between the studied problem and the apportionment of seats in a parliament is tackled and it is used to develop an ant algorithm approach to solve the problem. The algorithm is then compared to an exact procedure for a real life instance found in the metropolitan area of Barcelona.Postprint (published version

Diseño de rutas de recogida de residuos sólidos urbanos en el área metropolitana de Barcelona

Los problemas aso ciados a la recogida de residuos sólidos urbanos son muy variados. En este traba jo se presenta el problema de diseño de itinerarios de recogida y se muestran los resultados ofrecidos p or un pro cedimiento basado en colonias de hormigas a la recogida en un núcleo urbano del Área Metrop olitana de Barcelona.Postprint (published version

Solving an Urban Waste Collection Problem Using Ants Heuristics

This paper describes the methodology that we have applied for the solution of an urban waste collection problem in the municipality of Sant Boi de Llobregat, within the metropolitan area of Barcelona (Spain). The basic nature of the considered problem is that of a capacitated arc routing problem, although it has several specific characteristics, mainly derived from trafic regulations. We present the model that we have built for the problem, which results after an appropriate transformation of the problem into a node routing one. We also present the ant colonies heuristics that we have used to obtain the solutions to the problem. These combine constructive methods, based on nearest neighbor and on nearest insertion, with a local search that explores various neighborhoods. The application of the proposed methods gives results that improve considerably the ones that were previously used in the municipality.Peer Reviewe

Upper Barremian−lower Aptian charophyte biostratigraphy from Arrifes section (Algarve Basin, Southern Portugal): correlation with dinoflagellate cyst biostratigraphy

The Arrifes section (Algarve Basin, Southern Portugal) has been studied from the viewpoint of charophyte biostratigraphy. The previous sedimentological studies in this section showed that it is built of the interbedding of continental and marine facies that contain both marine and continental palynomorphs (pollen, spores, and dinoflagellates), providing an excellent sedimentary context to perform direct correlations between marine and continental domains. In the present work, the identified charophyte biozones have been correlated with dinoflagellate biozones previously recognized in the Arrifes section, being the first time that these two biochronologies can be directly correlated. From the charophyte biostratigraphy viewpoint, two assemblages are distinguished. The older one is found between 65 and 135 m of the stratigraphic section, and it is composed of the species Echinochara lazarii, Atopochara trivolvis var. triquetra, A. trivolvis var. trivolvis, Clavator grovesii var. jiuquanensis, Clavator harrisii var. harrisii, C. harrisii var. reyi, and C. harrisii var. zavialensis. This assemblage belongs to the upper Barremian-lower Aptian Clavator grovesii var. jiuquanensis Eurasian biozone and also to the Ascidiella cruciata-Pseudoglobator paucibracteatus European biozone and it is described in beds with the dinoflagellate cyst Subtilisphaera scabrata (lower to lowermost upper Barremian) and Odontochitina operculata (from upper Barremian upwards). The younger charophyte assemblage is found between 135 and 155 m of the stratigraphic section, and it is composed of the species A. trivolvis var. trivolvis, Clavator grovesii var. corrugatus, Clavator harrisii var. harrisii, C. harrisii var. reyi, and C. harrisii var. zavialensis. This assemblage belongs to Clavator grovesii var. corrugatus biozone, previously assigned to upper Aptian (Clavator grovesii var. lusitanicus biozone). However, in the Arrifes section, this assemblage is found in beds assigned to the dinoflagellate cyst Odontochitina operculata (from upper Barremian-lower Aptian). The direct correlation of the base of the C. grovesii var. corrugatus biozone with the dinoflagellate cyst O. operculata, indicates that the base of the Clavator grovesii var. corrugatus biozone is in the upper lower Aptian, which is slightly older than was previously suggested, and it is extended until the middle Albian

Models and procedures for electric energy distribution planning. A review

Distribution system planning is a key component to accomplish the service in a fast growing demand market, both from a technical point of view and from the economic costs management. In the near future, electric companies will need faster and cheaper planning tools to evaluate different scenarios and their consequences for the rest of the system and provide their clients whit safe reliable and economic energy. The objective of this paper is to review different articles about this subject trying to continue the previous work from Gonen and Ramírez-Rosado in 1986 (Gönen,1986).Postprint (published version