Previous research confirms that there is a major decline of pollinators worldwide. Investigations have mainly focused on pollination services in the agricultural landscapes and therefore, there is a lack of knowledge on the effects pollinators may have in urban environment. This paper examines the presence of honey bees in central parts of Stockholm, Sweden. The study presents what conditions, possibilities and motives there are behind the phenomenon of urban bee keeping. I found ten locations with beehives and a total of 18 hives within the delimited area. Nothing seems to indicate that conditions may limit the presence of honey bees. Given the opportunity to place beehives on the ground and on rooftops, the possibilities also seems to exist. According to the owners of the beehives motives are better harvests in connection to allotments, positive effects on flora and educational and marketing purposes.

Dissertation--Tübingen--Fakultät für Kulturwissenschaften, Eberhard-Karls-Universität. / Bibliogr. p. 379-391.

Texte remanié de: Thèse de doctorat--Science politique--Paris--IEP, 2005. / Bibliogr. p. 481-492.

No description available.

Thesis (M.A.) -- University of Adelaide, School of History and Politics, Discipline of Politics, 2003. / Bibliography: leaves 73-79.

This thesis focuses on algorithms solving the on-line Bin-Covering problem, when the items are generated from a known, stationary distribution. We introduce the Prospect Algorithm. The main idea behind the Prospect Algorithm is to use information on the item distribution to estimate how easy it will be to fill a bin with small overfill as a function of the empty space left in it. This estimate is then used to determine where to place the items, so that all active bins either stay easily fillable, or are finished with small overfill. We test the performance of the algorithm by simulation, and discuss how it can be modified to cope with additional constraints and extended to solve the Bin-Packing problem as well. The Prospect Algorithm is then adapted to achieve perfect packing, yielding a new version, the Prospect+ Algorithm, that is a slight but consistent improvement. Next, a Markov Decision Process formulation is used to obtain an optimal Bin-Covering algorithm to compare with the Prospect Algorithm. Even though the optimal algorithm can only be applied to limited (small) cases, it gives useful insights that lead to another modification of the Prospect Algorithm. We also discuss two relaxations of the on-line constraint, and describe how algorithms that are based on solving the Subset-Sum problem are used to tackle these relaxed problems. Finally, several practical issues encountered when using the Prospect Algorithm in the real-world are analyzed, a computationally efficient way of doing the background calculations needed for the Prospect Algorithm is described, and the three versions of the Prospect Algorithm developed in this thesis are compared.

Abstrakt.Syftet med denna studie är att ta reda på vad som kan göras i trädgårds- och balkongmiljöer för solitära bins överlevnad, då arter redan gått förlorade eller är rödlistade på grund av dåliga förutsättningar i fråga om habitat. Hur kan utformningen av designförslag se ut för trädgård och balkong? Vad innehåller lämpliga habitat samt hur ser hotbilden ut för solitära bin? Målet med denna litteraturstudie var att finna svar på mina frågeställningar. Utifrån de fakta som framkommit från resultaten har sedan designförslag utformats för trädgårds- och balkongmiljöer. Ökad biotopyta från forna tiders mosaiklandskap kan i ny tappning utformas som trädgårds- och balkongmiljöer i form av giftfria och blomrika små ängar, blommande kantzoner, diken och rabatter, krukväxter, blommande träd och buskar. Solitära bin behöver husrum, vatten att dricka och mat att äta i form av nektar- och pollenrika växter. De behöver blommande växter från tidig vår till sen höst för att överleva. Viktigt att sprida kunskap och förståelse för hur solitära bin lever sina liv så att människor kan samarbeta för att nå långsiktiga hållbara habitatlösningar. Solitära bin behöver många blommande växtytor som kan fungera som spridningskorridorer in i de urbana miljöerna där varenda liten kvadratmeter blommande yta har betydelse. Solitära bin ökar i antal med ökad biotopyta är fakta som designförslagen baserats på. Förödande hot för solitära bin är bland annat blombrist i urbana miljöer, besprutning med olika gifter, tambin som sprider sjukdomar, människans rädsla för små kryp samt förändrade livsmiljöer. / Abstract. The purpose of this study is to find out what can be done in gardens and balconies for solitary bees survival, species have already been lost or are red-listed because of poor conditions in terms of habitat. What can design-proposals look like for gardens and balconies? What do suitable habitats contain and what do threats look like for solitary bees?The goal with this literature study was to find answers to my questions. Based on facts that emerged from the results, design proposals have been made for gardens and balconies. Increased biotope-surface from ancient times mosaic-landscape can in modern environments like gardens and balconies be designed as non-toxic and flower-rich meadows, flowering border zones, ditches and flower beds, potted plants, flowering trees and shrubs. Solitary bees need shelter, water to drink and food to eat as in nectar and pollen-rich plants. They need flowering plants from early spring to late autumn to survive. It´s important to spread knowledge and understanding how solitary bees live their lives, that people can cooperate to achieve long-term sustainable habitat solutions. Solitary bees need many flowering plant-surfaces that can act as dispersal corridors in to urban environments, where every single square meter flowering-surface is of importance. Solitary bees increase in number with increasing biotope-surfaces which are facts that design proposals are based on. Devastating threats for solitary bees are floral shortage in urban areas, spraying with various poisons, domestic bees spreading diseases, human fear of small insects and altered habitats.

A presente pesquisa tem como objetivo estudar a integração entre dois temas clássicos da literatura de pesquisa operacional e gestão de operações: problemas de corte e empacotamento; e problemas de programação da produção. Ainda que sejam duas áreas intensamente exploradas e pesquisadas, e, ainda, que seja uma situação facilmente encontrada em sistemas de produção reais, abordagens de ambos problemas de forma coordenada ainda carecem de maiores pesquisas. Neste trabalho é feita uma revisão de ambos temas, com foco em problemas de bin packing e programação em ambiente de máquina única com objetivo de minimizar soma de atrasos e adiantamentos ponderados. Uma formulação matemática linear e inteira mista é proposta para o problema, contemplando as restrições que concernem a cada um e também à sua consideração simultânea. Como se trata de um problema que une dois outros, cada um NP-hard isoladamente, um método heurístico é proposto para obter uma solução interessante em tempos computacionais bastante reduzidos. Foram obtidas propriedades físicas de definição de data ideal de programação de um conjunto de itens atribuídos a um bin. Também é proposto um método para geração de um limitante inferior melhorado em relação a pacotes de otimização de mercado para o problema. Ambos métodos foram testados em uma massa de dados de 1.152 instâncias, geradas para retratar cenários de diferentes datas de entrega, setups, custos de atraso e adiantamento em relação à matéria-prima, tamanho de itens e número de itens na instância. Os resultados mostram-se largamente superiores aos obtidos por um otimizador genérico (CPLEX), embora ainda sejam gaps excessivamente grandes, o que reforça a dificuldade do problema. / The present research aims to explore the integration between two classic themes on operations research and operations management literature: cutting and packing problems; and production scheduling problems. Although they are intensive explored and researched areas and, besides, it\'s an easily found situation on real production systems, coordinated approaches of both themes still need deeper research. On this paper, it was done a review of both themes, focusing on bin packing problems and single-machine environment scheduling problems aiming to minimize total weighed earliness and tardiness. A mixed integer-linear mathematical formulation is proposed to the problem, including constraints referred to each problem and, also, to their simultaneous consideration. Once it\'s a problem that joins the other two, each one NP-hard solely, an heuristic method is proposed to obtain an interesting solution in reasonable computational times. Physical properties were identified, defining the best date to allocate a given lot of items to be processed together. Also, a lower bound generation method is proposed, improving the one generated by optimization softwares. Both methods were tested on a 1.152 instances mass of data, generated to represent well several scenarios of different due dates, setup times, earliness and tardiness costs compared to raw material, size of items and number the items the instance. Results show largely superiority the ones obtained by an optimization pack (CPLEX), although gaps are still excessively large, fact the reinforces problem\'s difficulty.

The purpose of bin packing is the effective apportionment of smaller elements in the bigger ones. The bin packing is being analysed in managment, computers, mathematics and researches of operations. The quality of the heuristic structural algorithm and time have been analysed in the work (the percent of the used material and the quality of the received waste). The results of the researches show that non-sorted bin packing algorithms cut better than bin packing sorted algorithms but the time of cutting grows longer when the number of finished products grow longer.

Made available in DSpace on 2014-12-17T15:14:53Z (GMT). No. of bitstreams: 1 FlodoaldoLSN_DISSERT.pdf: 1259869 bytes, checksum: 4ecb7fb8aaccb50fd4d8557e09d465fb (MD5) Previous issue date: 2010-12-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / On this study we have revisited the predicted tidal circularization theory in close binary systems with a evolved component. Close binaries suffer tidal interactions that tend to synchronize periods and circularize the orbits (Zahn 1977, 1989, 1992). According to Zahn s theory we compute the integral that give us the variation of the eccentricity in a binary under the influence of tidal force and we compare the integral results with new observations for 260 binary systems with orbital solutions. Our results confirm the success of the Zahn s theory with a new data and new stellar evolutionary models, on the other hand, our results points to the need for a better description of the role of convection on this theory / No presente estudo, ? revisitada a teoria que prev? a circulariza??o por efeito da mar? dos sistemas bin?rios, contendo componente evolu?da. Tais sistemas sofrem intera??es gravitacionais que tendem a sincronizar o per?odo orbital com o per?do de rota??o e tornar as ?rbitas circulares (Zahn 1977, 1989, 1992). Seguindo a teoria de Zahn, foi calculada, neste trabalho, a integral que descreve a varia??o da excentricidade em um sistema bin?rio sob a influ?ncia da for?a de mar? e foram comparados os resultados te?ricos das integrais com observa??es recentes para 260 sistemas bin?rios com elementos orbitais publicados. Os resultados descritos aqui confirmam por um lado o sucesso da teoria Zahn, sob a luz dos novos dados e novos modelos evolutivos e, por outro, aponta para a necessidade de uma melhor descri??o do papel da convec??o nessa teoria