Socioeconomic Networks with Long-Range Interactions

We study a modified version of a model previously proposed by Jackson and Wolinsky to account for communicating information and allocating goods in socioeconomic networks. In the model, the utility function of each node is given by a weighted sum of contributions from all accessible nodes. The weights, parameterized by the variable $\delta$, decrease with distance. We introduce a growth mechanism where new nodes attach to the existing network preferentially by utility. By increasing $\delta$, the network structure evolves from a power-law to an exponential degree distribution, passing through a regime characterised by shorter average path length, lower degree assortativity and higher central point dominance. In the second part of the paper we compare different network structures in terms of the average utility received by each node. We show that power-law networks provide higher average utility than Poisson random networks. This provides a possible justification for the ubiquitousness of scale-free networks in the real world.Comment: 11 pages, 8 figures, minor correction

Estimation of Cost Allocation Coefficients at the Farm Level Using an Entropy Approach

This paper aims to estimate the farm cost allocation coefficients from whole farm input costs. An entropy approach was developed under a Tobit formulation and was applied to a sample of farms from the 2004 FADN data base for Alentejo region, Southern Portugal. A Generalized Maximum Entropy model and Cross Generalized Entropy model were developed to the sample conditions and were tested. Model results were assessed in terms of their precision and estimation power and were compared with observed data. The entropy approach showed to be a flexible and valid tool to estimate incomplete information, namely regarding farm costs.Generalized maximum entropy; costs; estimation; Alentejo, FADN.

Differential temporal beta‐diversity patterns of native and non‐native arthropod species in a fragmented native forest landscape

An important factor that hinders the management of non‐native species is a general lack of information regarding the biogeography of non‐natives, and, in particular, their rates of turnover. Here, we address this research gap by analysing differences in temporal beta‐diversity (using both pairwise and multiple‐time dissimilarity metrics) between native and non‐native species, using a novel time‐series dataset of arthropods sampled in native forest fragments in the Azores. We use a null model approach to determine whether temporal beta‐diversity was due to deterministic processes or stochastic colonisation and extinction events, and linear modelling selection to assess the factors driving variation in temporal beta‐diversity between plots. In accordance with our predictions, we found that the temporal beta‐diversity was much greater for non‐native species than for native species, and the null model analyses indicated that the turnover of non‐native species was due to stochastic events. No predictor variables were found to explain the turnover of native or non‐native species. We attribute the greater turnover of non‐native species to source‐sink processes and the close proximity of anthropogenic habitats to the fragmented native forest plots sampled in our study. Thus, our findings point to ways in which the study of turnover can be adapted for future applications in habitat island systems. The implications of this for biodiversity conservation and management are significant. The high rate of stochastic turnover of non‐native species indicates that attempts to simply reduce the populations of non‐native species in situ within native habitats may not be successful. A more efficient management strategy would be to interrupt source‐sink dynamics by improving the harsh boundaries between native and adjacent anthropogenic habitats.Portuguese FCT‐NETBIOME – ISLANDBIODIV grant 0003/2011.info:eu-repo/semantics/publishedVersio

Safety and Tourism in the Post-COVID 19 Era

The COVID-19/SARSCOV2 global pandemic has originated inter alia health, economic and social crises. With limitations enforced by national governments, a global war on the virus has been followed by a vaccine war with scarcity problems on the production side, as many countries are struggling to protect their citizens. Tourism, one of the world´s most important economic areas with social-cultural, political and environmental impacts, has witnessed these problems from up close. Despite this, changes operated by the pandemic have taken tourism researchers and practitioners to profile new tourists, elaborate new ways to engage with them, follow emergent market tendencies, rethink tourism businesses and redevelop new tourism strategies for the future. This essay-like contribution is developed under the premise that because the rules of the touristic game have changed, we can rethink tourism concepts in a way that reflects the vast impacts of the pandemic upon the constant change, anxiety and volatile times we are experiencing as a society. I approach this discussion by briefly mentioning the implications that originated several changes observed in tourism studies by the so-called “cultural, critical and creative turns”. Then, drawing from the concept of transmodernity, tourism safety is addressed in a broad and updated view in the context of the tourism phenomenon in a post-pandemic reality. By aligning the discourse of transmodernity with the repercussions of the “cultural, critical and creative turns” in tourism studies I intend to contribute to the ongoing debated about how tourism consumption will develop in the near future.info:eu-repo/semantics/publishedVersio

UNDERSTANDING THE CREATIVE TOURISM EXPERIENCE IN CULTURAL AND CREATIVE EVENTS/FESTIVALS

The specialised consumption of creative tourism experiences and their presence in cultural and creative events and festivals, constitute examples of reflexive tourism consumption. Following the line of research about the specialised consumption of creative tourism experiences and events, this research aims to describe and account for examples where cultural and creative events/festivals represent opportunities for participatory experiences like workshops. The author developed a systematic review using SCOPUS database, to account for creative tourism experiences present at cultural and creative events/festivals. Thirteen documents from 2003 to 2019, were chosen and analysed as they represent the confrontation between cultural and creative events/festivals and creative tourism experiences principles. Findings show that authors don´t always refer directly to creative tourism experiences in the events and festival case studies analysed. Results were organized under two perspectives the in creative tourism literature such "event/festival centred approach" discussed in as the creative city, creative spectacles and cultural and creative capital co-creation. Nonetheless, important creative contributions for the development of creative capital present at cultural and creative events and festivals are highlighted. The recent establishment of creative tourism as a research area and the small number of papers found constitute limitations to the study.info:eu-repo/semantics/publishedVersio

CMOS analog-digital circuit components for low power applications

Dissertação de mestrado em Micro and NanoelectronicsThis dissertation presents a study in the area of mixed analog/digital CMOS power extraction circuits for energy harvester. The main contribution of this work is the realization of low power consumption and high efficient circuit components employable in a management circuit for piezoelectricbased energy harvester. This thesis focuses on the development of current references and operational amplifiers addressing low power demands. A brief literature review is conducted on the components necessary for the power extraction circuit, including introduction to CMOS technology design and research of known low power circuits. It is presented with multiple implementations for voltage and current references, as well for operational amplifier designs. A self-biased current reference, capable of driving the remaining harvesting circuit, is designed and verified. A novel operational amplifier is proposed by the use of a minimum current selector circuit topology. It is a three-stage amplifier with an AB class output stage, comprised by a translinear circuit. The circuit is designed, taking into consideration noise reduction. The circuit components are designed based on the 0.35mm CMOS technology. A physical layout is developed for fabrication purposes. This technology was chosen with consideration of robustness, costliness and performance. The current reference is capable of outputting a stable 12nA current, which may remain stable in a broad range of power supply voltages with a minimum voltage of 1.6V. The operational amplifier operates correctly at voltages as low as 1.5V. The amplifier power consumption is extremely low, around 8mW, with an optimal quiescent current and minimum current preservation in the output stage.A principal contribuição desta dissertação é a implementação de circuitos integrados de muito baixo consumo e alta eficiência, prontos a ser implementados num circuito de extração de energia com base num elemento piezoelétrico. Esta tese foca-se no desenvolvimento de um circuito de referência de corrente e um amplificador operacional com baixa exigência de consumo. Uma revisão da literatura é realizada, incluindo introdução à tecnologia Complementary Metal-Oxide-Semiconductor (CMOS), e implementação de conhecidos circuitos de baixo consumo. Várias implementações de referência de tensão e corrente são consideradas, e amplificadores operacionais também. Uma referência de corrente auto polarizada com extremo baixo consumo é desenvolvida e verificada. Um amplificador operacional original é proposto com uma topologia de seleção de corrente mínima. Este circuito é constituído por três estágios, com um estágio de saída de classe AB, e um circuito translinear. O circuito tem em consideração redução de ruído na sua implementação. Os circuitos são desenvolvidos com base na tecnologia 0.35mm CMOS. Uma layout foi também desenhada com o propósito de fabricação. A tecnologia foi escolhida tendo em conta o seu custo versus desempenho. A referência de corrente produz uma corrente de 12nA, permanecendo estável para tensões de alimentação de variáveis, com uma tensão mínima de 1.6V. O circuito mostra um coeficiente de temperatura satisfatório. O amplificador operacional funciona com tensão de alimentação mínima de 1.5V, com um consumo baixo de 8mW, com uma corrente mínima mantida no estágio de saída

A literature review on the role of cultural capital in creative tourism

Tourism literature mentions creative tourism as a special interest tourism allowing a wider participation of the tourist near local communities and their tangible and intangible cultural assets in opposition to traditional massive cultural tourism. The creative tourist has the opportunity to engage in meaningful experiences mainly through the act of cocreation. In the experience economy where experiences gain relevance in relation to services, some authors mention the development of several types of capital by different groups like supply managers, local communities and creative tourists. This is relevant to the study of tourism because various social groups mentioned above are gaining importance in the organization of supply and demand. A systematic review was used as methodology to analyze how cultural capital theory is being used in creative tourism. Findings showed that only few researches have applied capital theory to creative tourism and much more research is needed.info:eu-repo/semantics/publishedVersio