An epidemiological model with voluntary quarantine strategies governed by evolutionary game dynamics

During pandemic events, strategies such as social distancing can be fundamental to curb viral spreading. Such actions can reduce the number of simultaneous infections and mitigate the disease spreading, which is relevant to the risk of a healthcare system collapse. Although these strategies can be suggested, their actual implementation may depend on the population perception of the disease risk. The current COVID-19 crisis, for instance, is showing that some individuals are much more prone than others to remain isolated, avoiding unnecessary contacts. With this motivation, we propose an epidemiological SIR model that uses evolutionary game theory to take into account dynamic individual quarantine strategies, intending to combine in a single process social strategies, individual risk perception, and viral spreading. The disease spreads in a population whose agents can choose between self-isolation and a lifestyle careless of any epidemic risk. The strategy adoption is individual and depends on the perceived disease risk compared to the quarantine cost. The game payoff governs the strategy adoption, while the epidemic process governs the agent's health state. At the same time, the infection rate depends on the agent's strategy while the perceived disease risk depends on the fraction of infected agents. Results show recurrent infection waves, which were seen in previous epidemic scenarios with quarantine. Notably, the risk perception is found to be fundamental for controlling the magnitude of the infection peak, while the final infection size is mainly dictated by the infection rates. Low awareness leads to a single and strong infection peak, while a greater disease risk leads to shorter, although more frequent, peaks. The proposed model spontaneously captures relevant aspects of a pandemic event, highlighting the fundamental role of social strategies

Solution of an associating lattice gas model with density anomaly on a Husimi lattice

We study a model of a lattice gas with orientational degrees of freedom which resemble the formation of hydrogen bonds between the molecules. In this model, which is the simplified version of the Henriques-Barbosa model, no distinction is made between donors and acceptors in the bonding arms. We solve the model in the grand-canonical ensemble on a Husimi lattice built with hexagonal plaquettes with a central site. The ground-state of the model, which was originally defined on the triangular lattice, is exactly reproduced by the solution on this Husimi lattice. In the phase diagram, one gas and two liquid (high density-HDL and low density-LDL) phases are present. All phase transitions (GAS-LDL, GAS-HDL, and LDL-HDL) are discontinuous, and the three phases coexist at a triple point. A line of temperatures of maximum density (TMD) in the isobars is found in the metastable GAS phase, as well as another line of temperatures of minimum density (TmD) appears in the LDL phase, part of it in the stable region and another in the metastable region of this phase. These findings are at variance with simulational results for the same model on the triangular lattice, which suggested a phase diagram with two critical points. However, our results show very good quantitative agreement with the simulations, both for the coexistence loci and the densities of particles and of hydrogen bonds. We discuss the comparison of the simulations with our results.Comment: 12 pages, 5 figure

Cognitive appraisal in fish: stressor predictability modulates the physiological and neurobehavioural stress response in sea bass

The role of cognitive factors in triggering the stress response is well established in humans and mammals (aka cognitive appraisal theory) but very seldom studied in other vertebrate taxa. Predictability is a key factor of the cognitive evaluation of stimuli. In this study, we tested the effects of stressor predictability on behavioral, physiological and neuromolecular responses in the European sea bass (Dicentrarchus labrax). Groups of four fish were exposed to a predictable (signalled) or unpredictable (unsignalled) stressor. Stressor predictability elicited a lower behavioural response and reduced cortisol levels. Using the expression of immediate early genes (c-fos, egr-1, bdnf and npas4) as markers of neuronal activity, we monitored the activity of three sea bass brain regions known to be implicated in stressor appraisal: the dorsomedian telencephalon, Dm (putative homologue of the pallial amygdala); and the dorsal (Dld) and ventral (Dlv) subareas of the dorsolateral telencephalon (putative homologue of the hippocampus). The activity of both the Dm and Dlv significantly responded to stressor predictability, suggesting an evolutionarily conserved role of these two brain regions in information processing related to stressor appraisal. These results indicate that stressor predictability plays a key role in the activation of the stress response in a teleost fish, hence highlighting the role of cognitive processes in fish stress.info:eu-repo/semantics/publishedVersio

Students’ advances and regressions in the conceptual field of Thermodynamics

Esta pesquisa faz parte de um projeto mais amplo e tem como objetivo analisar avanços e retrocessos, e identificar as dificuldades e os possíveis invariantes operatórios apresentados por alunos do ensino médio e técnico, na aprendizagem de conceitos da Termodinâmica. A partir de um questionário a entrevista foi conduzida no sentido de os alunos responderem inicialmente às questões por escrito, e em seguida explicarem as suas respostas. Foram entrevistados quatro estudantes dos cursos de Eletrotécnica, Mecânica, Eletrônica e Química da Fundação Escola Técnica Liberato Salzano Vieira da Cunha em Novo Hamburgo, RS, Brasil. Este trabalho fundamenta-se na teoria dos campos conceituais de Vergnaud. Para Vergnaud, o domínio de um campo conceitual leva muito tempo, com avanços e retrocessos. Para ele, o conhecimento implícito tem papel fundamental no domínio de situações e só através da explicitação desse conhecimento é que se pode ajudar o aluno a avançar num campo conceitual. Este trabalho mostrou como é tortuoso o caminho para o domínio de um campo conceitual. Ele não é linear, possui avanços e retrocessos, filiações e rupturas. Obteve-se também a evidência dos seguintes possíveis invariantes operatórios: "ocorre transferência de calor somente quando os corpos estão encostados" e "é sempre necessário uma fonte de calor para aumentar a temperatura de um corpo".This study which is part of a larger study has the objective of analyzing progressions, regressions, and difficulties, as well as operational invariants, presented by students of a technical secondary school in the study of Thermodynamics. Initially, students answered a questionnaire in which they had to explain their answers. Then, four students from four different technical courses were interviewed. The study was conducted under the framework of Vergnaud’s conceptual fields Theory. According to this author students domain of a conceptual field is a long process, with advances and regressions. For him, the implicit knowledge is very important when students are dealing with problem-situations and it is only by making explicit this knowledge that the teacher may help them in mastering these situations and advancing in the corresponding conceptual field. The study has shown that, indeed, student’s trajectory in a conceptual field is nonlinear with progressions, regressions, continuities and ruptures. In addition, evidence was obtained suggesting that the following possible operational invariants were held by the students: “heat transfer occurs only when bodies are in direct contact”, “to increase the temperature of a body a heat source is always necessary”

Karyological study of Ololygon tripui (Lourenço, Nascimento and Pires, 2009), (Anura, Hylidae) with comments on chromosomal traits among populations

To increase the number of cytogenetic characters used in Ololygon tripui systematics, we applied some cytogenetic techniques such as Giemsa, C- and NOR-banding, and fluorescence in situ hybridization (FISH) with 18S rDNA and repetitive microsatellite DNA probes to the study of four populations from Minas Gerais State (southeastern Brazil). All populations showed 2n = 24 and FN = 48, and chromosomal formula 8m + 10sm + 6st. Nucleolar organizing regions (NORs) were located on chromosome pair 6 in all populations, although in the Tripuí locality additional markings were observed on one homologue of chromosome pair 3. These patterns were partially congruent with results obtained using the 18S rDNA FISH probe. The microsatellites repetitive DNA (GA) 15 and (CAT) 10 probes accumulated predominantly in the terminal region of all chromosomes. Chromosome morphology and Ag-NOR were conserved among populations, a conserved pattern in Ololygon Fitzinger, 1843. Repetitive DNA FISH probes patterns were similar among populations, but they revealed species-specific differences when compared with other species of the genus Ololygon, suggesting that molecular cytogenetics are potentially more informative in karyologically conservative taxa

Estudo da qualidade acústica em auditórios

As condições acústicas de um espaço devem proporcionar um ambiente sonoro adequado às atividades que aí são desenvolvidas, especialmente nos locais destinados à palavra, como por exemplo em salas de aula. O objetivo deste trabalho é o estudo da qualidade acústica, em especial a qualidade da audição da palavra durante as aulas, de quatro auditórios de uma instituição de ensino superior. Para a realização deste estudo foram selecionados auditórios com diferentes características, tendo-se realizado medições e análises do tempo de reverberação nos referidos ambientes para identificar os principais problemas existentes a nível da acústica de salas. Para além da avaliação ?in situ? do tempo de reverberação dos auditórios estudados, fez-se a avaliação subjetiva dos mesmos baseada em inquéritos aos alunos e professores que os frequentam.info:eu-repo/semantics/publishedVersio

Fasceite eosinofílica simulando esclerose lateral amiotrófica

Federal University of São Paulo Department of Neurology and Neurosurgery Neuromuscular Disorders UnitHospital São CristovãoUNIFESP, Department of Neurology and Neurosurgery Neuromuscular Disorders UnitSciEL