The Tourism Area Life Cycle Hypothesis: a Micro-Foundation

We provide a simple micro-foundation of the tourism area life cycle hypothesis, based on tourists’ utility maximization. As a result of social interactions among tourists which determine destinations popularity, the market share of visitors which decides to visit a specific destination follows a logistic dynamics, consistent with what predicted by the tourism area life cycle hypothesis. We show that different preference drivers explain the duration of the different tourism area life cycle stages: the net benefit from visiting the destination characterizes the exploration, involvement, and development phases, while social effects associated with destination popularity characterize the phases of consolidation and stagnation Different from previous studies our results hold true independently of whether we focus on the repeating or non-repeating segment of the tourism market. We also provide a calibration of our model to the case of the city of Venice (Italy) showing that it performs well in capturing the evolution of tourism in the historical center of the city over the last 60 years, suggesting that TALC-like dynamics may occur even in the context of cultural and heritage destinations

Meiofaunal ecology in harsh environments: refugia and stepping stones, a case study in a deglaciating Alpine area

Climate change and progressive glacier loss are leading to rapid ecological shifts in alpine aquatic systems. Rock glaciers and paraglacial features such as proglacial lakes, moraines, and taluses can alter the gradients of glacial influence along alpine river networks. Particularly relevant is the effect of rock glacial streams on invertebrates, although the hydrology and ecology of such high-elevation stream types is still scarcely known. We investigated the main meiofaunal component of benthic communities of different stream types in a deglaciating area of the Italian Alps, i.e., Crustacea Copepoda. We used an index of habitat mildness based on water temperature, channel stability, turbidity, and organic detritus, to measure the difference in community metrics over a gradient of habitat amelioration, driven by the mixing of distinct stream types (glacial, rock-glacial, snowmelt, mixed) and their interactions with paraglacial features. The composition of copepod communities of rock-glacial sites differed from the one of the other stream types, particularly it was very different from the kryal sites, and more similar to the rhithral and krenal ones. Under progressive deglaciation, rock glaciers and paraglacial features will increasingly influence the meiofaunal communities of alpine river networks. As they host a higher number of taxa and individuals than non-glacial locations, rock glacial streams may act as stepping stones facilitating colonization following glacier retreat. After glacier loss, rock glacial streams may represent climate refugia for cold adapted taxa and/or kryal specialists, because the slow thawing of their ice might sustain cold water conditions for a longer period of time

The Equity Premium Puzzle: An Application of an Agent-Based Evolutionary Model

We describe an agent-based model of a financial market with a stock and a bond. Agents compete in repeated rounds, decide whether to acquire costly information and can pick one of 16 strategies to allocate their investments, under evolutionary pressure driven by the comparison of the realized short-term revenues from trading. We show that, while in- formed traders survive in some cases, the equilibrium shares are strongly biased in favor of strategies that make little use of information and sys- tematically overestimate the riskiness of the stock. As a consequence, the majority of the population ends up in buying fewer stocks than would be otherwise expected or deemed rational. This evolutionary dynamics offers a novel way to explain the equity pre- mium puzzle first described by Mehra and Prescott (The equity pre- mium: A puzzle. Journal of Monetary Economics 1985), according to which it’s hard to find reasons for the widespread lack of investment in risky assets. Evolution based on a straightforward comparison of rev- enues is a simple and cognitively appealing avenue to reach a population of traders using (over-)cautious strategies to curb the risk of long-term “financial extinction”. Simulations run in NetLogo also demonstrate that very little information may be used in noisy markets or when the cost of information is substantial

Técnica de criação de Anastrepha fraterculus (Wied., 1830) (Diptera: Tephritidae) em laboratório utilizando hospedeiro natural.

Uma técnica para criação de todas as fases de desenvolvimento da mosca-das-frutas sul-americana, Anastrepha fraterculus (Wied., 1830) (Diptera: Tephritidae), em laboratório (T 24 ± 2°C; UR 70 ± 10% e fotofase 16 horas) utilizando dieta natural foi avaliada e descrita. Os adultos foram criados em gaiolas plásticas de polietileno transparente (41 x 29,5 x 30 cm) e alimentados com dieta artificial contendo extrato de soja, açúcar mascavo e gérmen de trigo, nas proporções de 3:1:1, além de água. Em cada gaiola, foi utilizada uma densidade média de 167 ± 25 casais. As fêmeas ovipositaram em frutos de mamão-papaia (Carica papaya L.) trocados a intervalos de 48 horas e mantidos em caixas plásticas (37 x 14 x 29 cm) com fundo coberto por vermiculita. Sobre a camada de vermiculita, foi colocada uma tela plástica de malha de 2 mm, para facilitar a retirada dos restos de mamão desidratado após o desenvolvimento larval. As larvas completaram o desenvolvimento no mamão passando à fase de pupa após 15 ± 2 dias. Em cada mamão (401 ± 16 gramas), foram coletadas 168 ± 27 pupas, obtendo-se 385 ± 44 pupas (viabilidade de 95 ± 2%) por semana, com peso médio de 1,33 ± 0,05 gramas a cada 100 pupas. Os insetos obtidos podem ser destinados a condução de bioensaios ou na manutenção da criação. A metodologia descrita permite o desenvolvimento de uma geração (ovo-adulto) a cada 32 ± 2 dias, perfazendo aproximadamente 11 gerações/ano.bitstream/item/31529/1/bop015.pd

Practical strategies for agent-based negotiation in complex environments

Agent-based negotiation, whereby the negotiation is automated by software programs, can be applied to many different negotiation situations, including negotiations between friends, businesses or countries. A key benefit of agent-based negotiation over human negotiation is that it can be used to negotiate effectively in complex negotiation environments, which consist of multiple negotiation issues, time constraints, and multiple unknown opponents. While automated negotiation has been an active area of research in the past twenty years, existing work has a number of limitations. Specifically, most of the existing literature has considered time constraints in terms of the number of rounds of negotiation that take place. In contrast, in this work we consider time constraints which are based on the amount of time that has elapsed. This requires a different approach, since the time spent computing the next action has an effect on the utility of the outcome, whereas the actual number of offers exchanged does not. In addition to these time constraints, in the complex negotiation environments which we consider, there are multiple negotiation issues, and we assume that the opponents’ preferences over these issues and the behaviour of those opponents are unknown. Finally, in our environment there can be concurrent negotiations between many participants. Against this background, in this thesis we present the design of a range of practical negotiation strategies, the most advanced of which uses Gaussian process regression to coordinate its concession against its various opponents, whilst considering the behaviour of those opponents and the time constraints. In more detail, the strategy uses observations of the offers made by each opponent to predict the future concession of that opponent. By considering the discounting factor, it predicts the future time which maximises the utility of the offers, and we then use this in setting our rate of concession. Furthermore, we evaluate the negotiation agents that we have developed, which use our strategies, and show that, particularly in the more challenging scenarios, our most advanced strategy outperforms other state-of-the-art agents from the Automated Negotiating Agent Competition, which provides an international benchmark for this work. In more detail, our results show that, in one-to-one negotiation, in the highly discounted scenarios, our agent reaches outcomes which, on average, are 2.3% higher than those of the next best agent. Furthermore, using empirical game theoretic analysis we show the robustness of our strategy in a variety of tournament settings. This analysis shows that, in the highly discounted scenarios, no agent can benefit by choosing a different strategy (taken from the top four strategies in that setting) than ours. Finally, in the many-to-many negotiations, we show how our strategy is particularly effective in highly competitive scenarios, where it outperforms the state-of-the-art many-to-many negotiation strategy by up to 45%.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Rock glaciers and paraglacial features influence stream invertebrates in a deglaciating Alpine area

This is the pre-peer reviewed version of the following article: Brighenti, S, Tolotti, M, Bertoldi, W, Wharton, G, Bruno, MC. Rock glaciers and paraglacial features influence stream invertebrates in a deglaciating Alpine area. Freshwater Biology. 2020; 00: 1– 14. https://doi.org/10.1111/fwb.13658, which has been published in final form at https://doi.org/10.1111/fwb.13658. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions

Identity, reputation and social interaction with an application to sequential voting

We analyze binary choices in a random utility model assuming that the agent's preferences are affected by conformism (with respect to the behavior of the society) and coherence (with respect to his identity). We apply the analysis to sequential voting when voters like to win

The dynamics of social interaction with agents’ heterogeneity

We analyze a class of binary dynamic models inspired by Brock and Durlauf (2001) on agents’ choices and social interaction. The main feature of our analysis is that agents are heterogeneous, in particular their attitude to interact with the choices of the other agents changes over time endogenously. Although dynamic approaches to the study of models with heterogeneous agents have been already applied in different fields, to our knowledge a complete study of an endogenously varying population of agents has not yet been pursued. As observed in Blume and Durlauf (2003), the main problem is given by the fact that with heterogeneous agents the system may be non reversible. We address these problems, we describe the (possible multiple) steady states of the processes involved, we analyze local and global stability and we discuss the similarities and the differences with respect to the literature. Applications are also provided

How the innovation diffusion models from the past can help us to explain marketing in the new media era

Even if the rhetoric of the Internet and the new digital media seems to have radically changed our technological environment, historical recurrences are relevant tools in order to analyze the future marketing. We propose a new multi-stage model able to bridge two different approaches, namely the adoption models à la Bass and the recent line of research concerning agent-based innovation diffusion models. Our technology allows us to find a closed form equation for awareness and adoption, taking into account heterogeneous population