Topological Complexity of Configuration Spaces

In this thesis we study the homotopy invariant TC(X); the topological complexity of a space X. This invariant, introduced by Farber in [15], was originally motivated by a problem in Robotics; the motion planning problem. We study relations between the topological complexity of a space and its fundamental group, namely when the fundamental group is ”small”, i.e. either has small order or small cohomological dimension. We also apply the navigation functions technique introduced in [20] to the study of the topological complexity of projective and lens spaces. In particular, we introduce a class of navigation functions on projective and lens spaces. It is known ([25]) that the topological complexity of a real projective space equals one plus its immersion dimension. A similar approach to the immersion dimension of some lens spaces has been suggested in [31]. Finally, we study the topological complexity (and other invariants) of random right-angled Artin groups, i.e. the stochastic behaviour of the topological complexity of Eilenberg-MacLane spaces of type K(G, 1), where G is a right-angled Artin group associated to a random graph

Ekstrak Daun Teh sebagai Reagen Alami (Natural Reagent) untuk Penentuan Logam Cu(II) menggunakan Sequential Injection Analysis (SIA)

Daun teh dapat digunakan sebagai reagen alami. Ekstrak daun teh mengandung polifenol yang memiliki banyak manfaat terhadap kesehatan. Senyawa polifenol utama yang terdapat dalam daun teh adalah katekin, epigallocatechin gallate (EGCG) dan epicatechin gallate (ECG). Salah satu sifat senyawa polifenol adalah kemampuannya dalam mengabsorbsi besi. Senyawa polifenol, khususnya katekin, memiliki kemampuan untuk mereduksi dan membentuk kelat dengan ion logam besi membentuk kompleks Fe-polifenol. Berdasarkan hal tersebut, maka ekstrak daun teh dapat diteliti untuk digunakan sebagai pengkompleks dalam penentuan logam, misalnya Cu(II) melalui pembentukan kompleks Cu-polifenol. Melihat pentingnya penggunaan reagen alami sebagai agen pengkompleks untuk mengurangi penggunaan bahan kimia berbahaya dan pentingnya analisis tembaga secara otomatis. Maka dalam penelitian beberapa tahapan yang dilakukan meliputi: pembuatan ekstrak daun teh sebagai reagen natural, kuantifikasi tembaga menggunakan SIA dengan ekstrak daun teh sebagai reagen pengkompleks dengan beberapa optimasi yaitu, optimasi volume ekstrak daun teh, waktu reaksi, laju alir produk menuju detektor; dan penentuan kadar tembaga dari sampel air. Dari hasil penelitian dapat disimpulkan bahwa, penentuan kadar Cu (II) secara SIA dapat dilakukan dengan cara menentukan kondisi optimum pembentukan senyawa kompleks Cu-Ekstrak daun teh dan limit of detection (LOD). Hasil optimasi tercapai pada, volume ekstrak daun teh 600 μL, waktu reaksi 18 detik, laju alir 55 μL/s dan LOD yang sebesar 1,3527

Reproductive biology of Megabalanus azoricus (Pilsbry), the Azorean Barnacle

Copyright © 2007, Taylor & Francis.The reproductive biology of Megabalanus azoricus (Pilsbry), the commercially exploited barnacle in the Azores, was studied in an attempt to provide the scientific basis for the sustainable management of this heavily exploited regional marine resource. Both the Ospar Commission and WWF have expressed concern for this species, considering it at risk and in urgent need for scientific study. Barnacles were collected every month from shallow water (.3 m depth) around São Miguel Island from October 2004 to September 2005. Individuals were measured and gonads processed for histology and analysed with a stereological method. M. azoricus has a hermaphroditic reproductive system with separate gonads and it was possible to describe the various stages of gametic maturation in both. Data on fertility were also obtained by egg counts and calculation of the Gonadosomatic index (GSI). Throughout the year, some specimens of M. azoricus can be found that rare mature, but two reproductive peaks were observed, one in January and a smaller one in July. A strong positive correlation between GSI and environmental factors such as photoperiod and water temperature was observed.CIRN (Research Centre in Natural Resources), Universidade dos Açores

Modeling Movement of Tourists : Tools and Application in São Miguel Island, Portugal

Tourism contributes to the development of many regions. Different factors affect the movement of tourists within a destination. Those factors are related to the tourist characteristics, like the time budgets, preferences or destination knowledge, and to the destination features, like the attraction characteristics or accessibility level. Tourist decisions aren’t always done in a rational way. Emotions add further complexity to the human decision process. The use of footpaths can play an important role in the satisfaction of tourists, helping them discover the territory and giving them access to different types of attractions. The existence of a mathematical model that integrates the main factors related to the movement of independent tourists within a destination, in a dynamic way, will make possible the creation of an adaptable software tool. This tool will meet the specific needs of tourists, allowing the use of the network in an optimal way by the different tourist profiles, and the needs of the regional government and business, permitting better decisions and the offer of relevant tourism products. This article identifies the main tourists’ mobility criteria in the São Miguel island territory, Azores, Portugal, recognizes the necessary modelling process and identifies the basis for the construction of the mathematical model that explains the movement of tourists within the destination

Logistic optimization in tourism networks

55th European Regional Science Association Congress, Lisbon, Portugal (25-28 August 2015).Tourism doesn't depend on a specific resource and enable the integration of local populations and economies, generating benefits that have a stronger effect on regional development. Literature main stream identifies tourism as one of the activities with high impact on the development and for many regions, especially for small remote territories. In our natural laboratory, the Azores Island of São Miguel, an important share of tourists identifies adventure, leisure and touch with nature, as the main reasons for the visit. In this sense, footpaths are an important tool to promote environmental and social education, encouraging the observation and improving the knowledge about the nature and endorsing greater respect for our heritage. Its use can contribute to the satisfaction of tourists, promoting tourism and the region's development during their movements on the tourism network, tourists appreciate different types of attractions and need the support of a set of facilities. Tourist decisions aren’t always done in a rational way, emotions add even more complexity to the human decision process. The movement of tourists within a destination and the level of satisfaction that they can achieve, depends on factors related to tourist characteristics, like the time budgets, preferences or destination knowledge, and destination features related to attractions characteristics or accessibility level. In order to offer relevant tourism products, stakeholders need to understand how tourists take their decisions and what their preferences are. That knowledge will be able to build optimized tourism products that meet the tourists’ preferences and facilities that allow the use of the network in an optimal way by the different tourist profiles. The existence of a mathematical model that incorporates the main factors that explain the movement of independent tourists within a destination, in a dynamic way, will make possible the creation of an adaptable software tool. This tool will meet the specific needs of tourism and the needs of regional business and government, according to their endogenous features, improving the optimization of investments in transport networks and the infrastructure that supports tourism related activities. This article is based on the authors’ previous research and identifies the relevance of tourism for regional development and finds the main tourists’ mobility criteria on the studded territory, using as main support the footpath network. Additionally, recognises the necessary modelling process and developed the foundation for the building of the mathematical model that explains the movement of tourists within the destination, making possible a future adaptable software tool

Yardstick competition among Portuguese municipalities: the case of urban property tax (IMi)

In a previous paper, we have tested if there is empirical evidence on the existence of strategic interaction among Portuguese municipal executives when they set rates of municipal taxes and in particular if we are in the presence of yardstick competition.Departamento de Economí

Obtaining Data Values from Tourist Preferences

Satisfied customers are the main sustainability factor for the viability of any activity, and tourism has increasing relevance to the global economy and the economic development of many regions. In order to create better matches between tourist demands and preferences and the local supply, an understanding of tourists as decision makers is necessary. The aim of this work is to introduce a mathematical model that explains the decision-making process of tourists, other consumers, and tourism business managers. We used a mathematical model, taking into consideration the preferences of individuals and their strengths during the exploration and use of tourism resources. The integration of preferences into an IT tool provided extra support to the decisions of tourists and allowed better choices to be made in the execution of travel plans. In addition, the model can be used by resource managers. Understanding how tourists make decisions in each different situation can improve the allocation of available resources to satisfy their expectations. The proposed model is also adaptable to situations where it is necessary to decide among different options with a high degree of complexity.This work was supported by FCT, the Portuguese national funding agency for science, research and technology, Portugal. Projects UIDB/04674/2021. TRENMO S.A.info:eu-repo/semantics/publishedVersio

Heterocyclic aromatic amines formation in grilled fatty fish

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