The Cry Wolf Effect in Evacuation: a Game-Theoretic Approach

In today's terrorism-prone and security-focused world, evacuation emergencies, drills, and false alarms are becoming more and more common. Compliance to an evacuation order made by an authority in case of emergency can play a key role in the outcome of an emergency. In case an evacuee experiences repeated emergency scenarios which may be a false alarm (e.g., an evacuation drill, a false bomb threat, etc.) or an actual threat, the Aesop's cry wolf effect (repeated false alarms decrease order compliance) can severely affect his/her likelihood to evacuate. To analyse this key unsolved issue of evacuation research, a game-theoretic approach is proposed. Game theory is used to explore mutual best responses of an evacuee and an authority. In the proposed model the authority obtains a signal of whether there is a threat or not and decides whether to order an evacuation or not. The evacuee, after receiving an evacuation order, subsequently decides whether to stay or leave based on posterior beliefs that have been updated in response to the authority's action. Best-responses are derived and Sequential equilibrium and Perfect Bayesian Equilibrium are used as solution concepts (refining equilibria with the intuitive criterion). Model results highlight the benefits of announced evacuation drills and suggest that improving the accuracy of threat detection can prevent large inefficiencies associated with the cry wolf effect.Comment: To be published in Physica

Photochemistry and Pinhole Photography: An Interdisciplinary Experiment

This interdisciplinary activity combines chemistry and art through the construction and use of a pinhole camera. We focused on the chemistry of the black and white photographic process as the science component of this activity. The reactions involved are good examples of photochemistry and multiphase chemical reactions, since the light sensitive materials (silver halides) are in the form of a gelatin emulsion of microscopic crystals

Assortativity evolving from social dilemmas

Assortative mechanisms can overcome tragedies of the commons that otherwise result in dilemma situations. Assortativity criteria include genetics (e.g. kin selection), preferences (e.g. homophily), locations (e.g. spatial interaction) and actions (e.g. meritocracy), usually presuming an exogenously fixed matching mechanism. Here, we endogenize the matching process with the aim of investigating how assortativity itself, jointly with cooperation, is driven by evolution. Our main finding is that only full-or-null assortativities turn out to be long-run stable, their relative stabilities depending on the exact incentive structure of the underlying social dilemma. The resulting social loss is evaluated for general classes of dilemma games, thus quantifying to what extent tragedy of the commons may be endogenously overcome

Electing Law Enforcement Leadership: Examining the Effects of Politics and Job-related Qualifications on Personnel Assessment and Decisions for Sheriff

Calls for police reform have become frequent in the United States. Efforts to enact meaningful organizational change will require support from senior law enforcement leadership. Personnel selection for several of these positions (e.g., Sheriff) occurs via local election. Little is known, however, about the factors that influence voters’ assessment of candidates for these positions and the extent to which decision-making for personnel selection via election is influenced by the same beliefs (e.g., person-job and person-organization fit) as more traditional approaches to hiring. This study explores the extent to which voters’ perceptions of two candidates for the position of Sheriff are affected by their job-related qualifications and political affiliations – and the extent to which these perceptions influence voter behavior. Results suggest that the combination of participants’ and candidates’ political affiliations accounted for substantial incremental variance in evaluations of the candidates’ person-job fit, person-organization fit, and overall suitability for employment above-and-beyond differences in their job-related qualifications; and that participants were approximately 39% more likely to vote for the candidate with lower job-related qualifications when that candidate shared their political affiliation. Reports about the extent to which republicans and democrats value/ support police practices provide insights as to why these effects were observed

FTIR: uma potencial metodologia para o rastreio de marcadores de envelhecimento no DNA

Com o aumento da esperança média de vida, estudar o envelhecimento saudável tem vindo a tornar-se mais relevante. Muitas das perdas funcionais relacionadas com a idade ocorrem através dos danos oxidativos e um dos biomarcadores mais utilizados para estudar estes danos, também usado como preditor da idade biológica, é a quantidade de 8-oxo-2´-deoxoguanosina (8- OHdG). Este composto corresponde à versão oxidada mais frequente das guaninas do DNA, e a sua disponibilidade e estabilidade a longo prazo é superior à de outros biomarcadores. As técnicas utilizadas para a medição do stresse oxidativo no DNA, em sua maioria, apresentam diversas desvantagens, para além de degradarem a amostra, apresentam um custo elevado e envolvem procedimentos demorados ou necessitam de serem complementadas com outras técnicas. Para tentar ultrapassar estas limitações este trabalho propõe o uso de espectroscopia de infravermelho com transformadas de Fourier (FTIR) para a medição de níveis de 8-OhdG em amostras humanas com DNA. Esta técnica foi utilizada devido à sua sensibilidade, ao reduzido tempo de análise, ao baixo risco de contaminação das amostras, ao facto de necessitar pouca amostra e ter baixo custo. No presente estudo recorreu-se a ELISA como método de validação, que se comparou como FTIR, para a quantificação do analito 8-OhdG, em amostras de urina e de DNA extraído e purificado. Apesar de não ter sido possível obter uma boa correlação entre os resultados obtido por ambas as técnicas analíticas, foi possível tanto a deteção quanto a quantificação deste composto, por FTIR, em ambos os tipos de amostras. Com este trabalho foi possível definir as condições experimentais necessárias para a utilização do FTIR na quantificação de 8-OHdG tendo-se estabelecido um protocolo laboratorial, que deverá ser utilizado como ponto de partida em estudos futuros. Para além disso, os espectros provenientes do FTIR foram explorados para testar a sua utilidade na determinação de outros biomarcadores relevantes em simultâneo.With the increase in average life expectancy, studying healthy aging has become more relevant. Many of the age-related functional losses occur through oxidative damage and one of the most used biomarkers to study these damages, also used as a predictor of biological age, is the amount of 8-oxo-2´- deoxoguanosine (8-OHdG). This compound corresponds to the most frequent oxidized version of DNA guanines, and its availability and long-term stability is superior to that of other biomarkers. The techniques used to measure oxidative stress in DNA, for the most part, have several disadvantages, in addition to degrading the sample, presenting a high cost and involving lengthy procedures or need to be complemented with other techniques. In order to try to overcome these limitations this work proposes the use of infrared spectroscopy with Fourier transform (FTIR) to measure 8-OhdG levels in human samples with DNA. This technique was used due to its sensitivity, the reduced analysis time, the low risk of contamination of the samples, together with the fact that it requires little sample and has a low cost. In the present study, ELISA was used as a validation method, and results were compared to those from FTIR, for the quantification of the 8-OhdG analyte, in both urine and extracted DNA samples. Although it was not possible to obtain a good correlation between the results obtained by both analytical techniques, it was possible to detect and quantify this compound, by FTIR, in both types of samples. With this work it was possible to define the experimental conditions necessary for the use of FTIR in the quantification of 8-OHdG, and a laboratory protocol was established, which should be used as a starting point in future studies. In addition, the spectra from the FTIR were explored to test their usefulness in determining other relevant biomarkers at the same time.Mestrado em Biologia Molecular e Celula