Developmental self-construction and -configuration of functional neocortical neuronal networks.

The prenatal development of neural circuits must provide sufficient configuration to support at least a set of core postnatal behaviors. Although knowledge of various genetic and cellular aspects of development is accumulating rapidly, there is less systematic understanding of how these various processes play together in order to construct such functional networks. Here we make some steps toward such understanding by demonstrating through detailed simulations how a competitive co-operative ('winner-take-all', WTA) network architecture can arise by development from a single precursor cell. This precursor is granted a simplified gene regulatory network that directs cell mitosis, differentiation, migration, neurite outgrowth and synaptogenesis. Once initial axonal connection patterns are established, their synaptic weights undergo homeostatic unsupervised learning that is shaped by wave-like input patterns. We demonstrate how this autonomous genetically directed developmental sequence can give rise to self-calibrated WTA networks, and compare our simulation results with biological data.

In Memoriam: Herbert E Wright Jr 1917-2015

Herbert E Wright Jr was one of the foremost Quaternary scientists of the last century. He made wide ranging contributions to our understanding of the late-Quaternary of North and South America, Europe, Asia and Africa. This was based largely on reconstructing palaeoenvironments from lake sediments and included the important implications for glacial, vegetational, fire and climatic history, geoarchaeology and conservation. Many of his inter-disciplinary research projects involved fieldwork with his graduate students and co-workers from the University of Minnesota where he created and led the renowned Limnological Research Center. Perhaps his most outstanding contribution was as an instigator of the Co-operative Holocene Mapping Project (COHMAP). This triggered a paradigm shift in Holocene climatic research involving the comparison of climate-model simulations of past climates with palaeoclimatic data.

A mixed-integer linear programming approach to the optimization of event-bus schedules: a scheduling application in the tourism sector

This paper deals with “The Enchanted Journey,” which is a daily event tour booked by Bollywood-film fans. During the tour, the participants visit original sites of famous Bollywood films at various locations in Switzerland; moreover, the tour includes stops for lunch and shopping. Each day, up to five buses operate the tour. For operational reasons, however, two or more buses cannot stay at the same location simultaneously. Further operative constraints include time windows for all activities and precedence constraints between some activities. The planning problem is how to compute a feasible schedule for each bus. We implement a two-step hierarchical approach. In the first step, we minimize the total waiting time; in the second step, we minimize the total travel time of all buses. We present a basic formulation of this problem as a mixed-integer linear program. We enhance this basic formulation by symmetry-breaking constraints, which reduces the search space without loss of generality. We report on computational results obtained with the Gurobi Solver. Our numerical results show that all relevant problem instances can be solved using the basic formulation within reasonable CPU time, and that the symmetry-breaking constraints reduce that CPU time considerably.

Consumption and food production in crisis time: Swiss consumption co-operations as farmers at the End of World War I

During the last two years of World War I food supply in Switzerland declined and caused shortcomings in consume, leading to social distress and conflict. Mainly two important factors caused these problems: First, Switzerland was highly dependent on food imports and during the war traditional supply lines faded. Second, weather extremes in the years 1916–1917 caused crop failure all over Europe and North America, which intensified the decline of food trade between the nations. In 1918 a conflict between classic urban consumers, such as workers, and famers erupted due to the food shortcomings and led to a lasting discord between urban and agrarian regions in Switzerland. But there was not only disharmony and conflict between the urban and agrarian regions. As a matter of fact several agents (urban and agrarian) interested in presenting adequate coping strategies to overcome the food shortages developed ideas of alternative ways of food production and supply since 1917. The aim of the paper is to outline these strategies that were undertaken to create a new era of food production that was not solely dependent on the agrarian sector or the import-trade. Actual growing of vegetables in estate areas is an important, but just one, factor of establishing a new system of food production, distribution and consume. The market-leading grocery stores in Switzerland nowadays (Coop and Migros) started their business during that time as co-operatives establishing new forms of distribution and food-production. So the interest of the paper is not only in actual «urban farming», but it wants to share some light on how swiss urban and agrarian spheres overlapped their functions in order to create a modern system of agro food-chains at the beginning of the interwar period.