Esse trabalho oferece uma avaliação da abundância do papagaio-de-peito-roxo (Amazona vinacea) para 2016 e 2017, combinando contagens em dormitórios ao longo de toda a distribuição da espécie, em escala global, com amostragens replicadas em dormitórios na região oeste de Santa Catarina (WSC), em escala local, Brasil. As contagens em escala global resultaram em 3888 e 4066 indivíduos em 2016 e 2017, respectivamente. As estimativas para o WSC foram de 945 ± 50 e 1393 ± 40 para os mesmos dois anos. Não foi observada nenhuma evidência de crescimento populacional de 2016 para 2017, pois o acréscimo no número de indivíduos foi acompanhado por aumento do esforço amostral em ambas escalas. Quando extrapolamos a abundância no WSC para toda a área de distribuição da espécie, segundo a IUCN, e pressupondo densidade homogênea, obtivemos valores que estão acima da contagem na escala global, mas dentro da mesma ordem de magnitude. Nosso resultado oferece uma base sólida para afirmar que o tamanho populacional global de A. vinacea é de milhares de indivíduos, mas não dezenas de milhares. Realizamos um esforço sistemático para considerar as principais fontes de incerteza na estimativa de abundância da espécie. Cada contagem, tanto na escala local quanto na global, incluíram visitas em todos os dormitórios conhecidos dentro de um intervalo de 10 dias, evitando duplas contagens devido ao movimento dos papagaios entre dormitórios. No WSC, a abundância foi estimada usando um N-Mixture Model implementado em contexto Bayesiano. Apesar de nossa estimativa de tamanho populacional e de área de distribuição serem maiores do que as consideradas pela IUCN, sugerimos que A. vinacea permaneça na categoria “Em Perigo”, até que sejam realizados estudos sobre tendência populacional. / We offer an assessment of Vinaceous parrot (Amazona vinacea) abundance in 2016 and 2017, combining roost counts over the whole range of the species, with a replicated survey of roosts at the local scale, in western Santa Catarina state (WSC), Brazil. The whole range counts amounted to 3888 and 4066 individuals in 2016 and 2017, respectively. The WSC estimates were 945 ± 50 and of 1393 ± 40 individuals, for the same two years. We found no evidence of population growth from 2016 to 2017 because the increase in numbers is accompanied by an increase in observation effort both in WSC and at the whole-range scale. When extrapolating the WSC abundance estimate to the whole IUCN extant range of the species under the simplifying assumption of homogenous population density, we obtain values above the whole-range counts, but within the same order of magnitude. Such result offers a sound basis for putting the global population size of A. vinacea in the thousands of individuals, but not in the tens of thousands of individuals. We made a systematic effort to address key sources of uncertainty in parrot abundance estimation. Each count, at the local or whole-range scale, includes visits to all relevant roosts within less than ten days time to avoid double counting due to movement between roosts. At the local scale, we estimated abundance using an N-Mixture Model of replicated count data, implemented in a Bayesian framework. Even though we estimate a larger population size and a bigger geographic range that those currently reported by the IUCN, we suggest that A. vinacea should remain in the ‘Endangered’ IUCN threat category, pending further investigation of population trends.

nÃo hà / This research aims to analyze variation in the use of the imperfect of indicative and imperfective periphrases the past, literary memories produced in 2010 and 2012, by students of the 7th and 8th years, finalists of the Portuguese Language Olympiad Writing the Future. Accordingly, it intends to investigate factors (linguistic and extra-linguistic) motivate the choice of one form or another. Therefore, is based on the Sociofuncionalism the postulates defended by Tavares (2003), resulting theoretical wedding between Sociolinguistics variational (Weinreich, Labov And HERZOG, 1968; Labov, 1972, 1978, 1994, 2001, 2003, 2010) and the US shed functionalism (cf. Givon, 1995, 2001; HOPPER, 1991; HOPPER & TRAUGOTT, 1993; TRAUGOTT, 1995. the corpus consists of 2205 data imperfective forms of past collected from 76 of literary texts memories , and in 1926 these data imperfect indicative past tense, for a total of 87.3% of the total, and 279 forms of imperfective periphrases past, totaling a percentage of 12.7% of the total incidence. The outcomes of the rounds statistics done using the software GoldVarb revealed that the phenomenon under study is motivated by linguistic factors, as imperfective function (episodic, habitual, iterative and progressive), semantic-discursive kind of verb (process culminated, culmination, activity and state), type prayer (coordinated asyndetic, subordinate adverbial, adjectival subordinate, coordinated syndetic, principal, absolute and conditional substantive), aspectual modifier (quantifier, durative, punctual and without modifier) and polarity (positive and negative), having been discarded by the statistics rounds factors narrative of the plan: figure and ground and geographic regions for failing to submit the relevant motivation of the imperfective forms under review. Thus, the results obtained and analyzed showed us how prototypical contexts for each form under the following analysis: the imperfect codes, prototypically, episodic role, culminating with process verb in affirmative prayer coordinated asyndetic with quantifier modifier; the periphrasis, in turn, presents, prototypically, progressive encoding function, with state verbs in negative substantive subordinate clauses, in the presence of aspectual point modifier. / Esta pesquisa tem por objetivo analisar variaÃÃo no uso do imperfeito do indicativo e de perÃfrases imperfectivas de passado, em memÃrias literÃrias produzidas em 2010 e 2012, por alunos do 7o e do 8o anos, finalistas da OlimpÃada de LÃngua Portuguesa Escrevendo o Futuro. Nesse sentido, intenta-se investigar fatores (linguÃsticos e extralinguÃstico) motivam a escolha por uma ou outra forma. Para tanto, fundamenta-se nos postulados do Sociofuncionalismo, defendidos por Tavares (2003), resultante do casamento teÃrico entre a SociolinguÃstica Variacionista, (WEINREICH, LABOV E HERZOG, 1968; LABOV, 1972, 1978, 1994, 2001, 2003, 2010), e o Funcionalismo de vertente norte-americana (cf. GIVÃN, 1995, 2001; HOPPER, 1991; HOPPER &TRAUGOTT, 1993; TRAUGOTT, 1995). O corpus à formado por 2205 dados de formas imperfectivas de passado coletados de 76 textos de memÃrias literÃrias, sendo 1926 destes dados de pretÃrito imperfeito do indicativo, perfazendo um total de 87,3% do total, e 279 formas de perÃfrases imperfectivas de passado, que totalizam um percentual de 12,7% do total de ocorrÃncias. Os resultados decorrentes das rodadas estatÃsticas realizadas pelo programa computacional GoldVarb revelaram que o fenÃmeno em estudo à motivado por fatores linguÃsticos, como funÃÃo imperfectivas (episÃdica, habitual, iterativa e progressiva), tipo semÃntico-discursivo do verbo (processo culminado, culminaÃÃo, atividade e estado), tipo de oraÃÃo (coordenada assindÃtica, subordinada adverbial, subordinada adjetiva, coordenada sindÃtica, principal, absoluta e subordinada substantiva), modificador aspectual (quantificador, durativo, pontual e sem modificador) e polaridade (positiva e negativa), tendo sido descartados pelas rodadas estatÃsticas os fatores plano da narrativa: figura e fundo e regiÃes geogrÃficas por nÃo terem apresentado relevÃncia na motivaÃÃo por uma das formas imperfectivas sob anÃlise. Dessa forma, os resultados obtidos e analisados revelaram-nos como contextos prototÃpicos para cada forma sob anÃlise os seguintes: o imperfeito codifica, prototipicamente, funÃÃo episÃdica, com verbo de processo culminado, em oraÃÃo coordenada assindÃtica afirmativa, com modificador quantificador; a perÃfrase, por sua vez, apresenta-se, prototipicamente, codificando funÃÃo progressiva, com verbos de estado, em oraÃÃes subordinadas substantivas negativas, na presenÃa de modificador aspectual pontual.

This study investigates the market conditions under which the Greek manufacturing sectors operate, and provides a formal measurement and determination of the observed degree of rigidity in nominal prices using panel modelling techniques. Two parameters in particular are found to capture the essence of market imperfections and price rigidity arising from various sources: the first parameter is conjectural variation elasticity which defines the degree of market divergence from perfect competition; and the last parameter refers to the speed of price adjustment towards the equilibrium level, which is estimated along with a set of important factors that affect this parameter. The data sample of this research consists of 56 3-digit manufacturing sectors, as defined by Eurostat (NACErev2) over the period 1980-2012, while the econometrical approach mainly incorporates the Fixed and Random Effects Model for panel data. The estimation process is divided into four steps: in the first step, the degree of market power and the speed of price adjustment are estimated for the whole manufacturing industry; in the second step, the same process is reiterated for the 3-digit sectors individually; in the third step the estimations are conducted for each year over 1980-2012; in the last step, the effects of a set of variables on the speed of price adjustment are estimated in order to provide an adequate interpretation of how market imperfections and price rigidities can be formed and how they relate to each other. By using the Greek economy as a case study, the empirical results provide significant evidence of a degree of market power similar to the one of a duopoly accompanied by relatively slow price adjustment in the 56 manufacturing sectors and the 33 years over 1980-2012.

It is a study of the imperfect mediation in Paul Ricoeur. We hold the view that the ricoeurian thought is articulated based on the notion of imperfect mediation, partial and finite, especially in distinction to the mediation of Hegelian sense is defined in absolute terms. Sustaining this thesis implies on the one hand, to rebuild some internal aspects to the work of Ricoeur, notably that qualify as the three Hegelian temptations, namely: the absolute temptation in the Spirit, in history and in the state. Otherwise, implies examine some theses that prescribe solutions contrary to ours. One is the thesis that defends the unity of Ricoeur's work based on the symbol of paradigms, text and translation; the other is defending the unity of his work around the symbol. In contrast, we understand that symbol, text and translation are but different ways of renouncing all forms of full mediation. In addition, the results we seek to ensure that the imperfect, open and fragmentary mediation remains an uninterrupted dialectic that articulates the self with the other, the identity with otherness. / Trata-se de um estudo sobre a mediação imperfeita em Paul Ricoeur. Sustentamos a tese de que o pensamento ricoeuriano se articula com base na noção de mediação imperfeita, parcial e finita, principalmente em distinção à mediação de sentido hegeliana que se define em termos absolutos. Sustentar tal tese implica, de um lado, em reconstruir alguns aspectos internos à obra de Ricoeur, notadamente o que qualificamos como as três tentações hegelianas, a saber: a tentação do absoluto no Espírito, na História e no Estado. De outro modo, implica em examinar algumas teses que prescrevem soluções contrárias a nossa. Uma delas é a tese que defende a unidade da obra de Ricoeur com base nos paradigmas do símbolo, texto e tradução; a outra é a que defende a unidade de sua obra em torno do símbolo. Contrariamente, entendemos que símbolo, texto e tradução não são mais que diferentes formas de renunciar a toda e qualquer forma de mediação total. Além disso, entre os resultados procuramos assegurar que a mediação imperfeita, aberta e fragmentária se mantém numa dialética ininterrupta que articula o si-mesmo com o outro, a identidade com a alteridade.

General game playing is an area of artificial intelligence which focuses on creating agents capable of playing many games from some class. The agents receive the rules just before the match and therefore cannot be specialized for each game. Deepstack is the first artificial intelligence to beat professional human players in heads-up no-limit Texas hold'em poker. While it is specialized for poker, at its core is a general algorithm for playing two-player zero-sum games with imperfect information - continual resolving. In this thesis we introduce a general version of continual resolving and compare its performance against Online Outcome Sampling Monte Carlo Counterfactual Regret Minimization in several games.

<p>In many economic settings agents behave strategically. Understanding and, sometimes regulating, that behavior is often crucial to enhance the efficiency with which scarce resources are allocated. A peculiar feature of economics is that cooperation among agents sometimes boosts efficiency, and sometimes hinders it. Social dilemmas, highly ubiquitous in economics, are situations in which cooperation boosts efficiency. Highly concentrated markets where a few firms operate, are situations in which cooperation (also known as collusion) among firms hinders efficiency. In such markets competition, rather than cooperation, boosts efficiency. In this dissertation, I study how uncertainty affects cooperation in social dilemmas, and how the presence of cooperative firms affects competition in concentrated markets.</p> <p><br></p> <p>Both of the settings I study in this dissertation (social dilemmas with noisy payoffs and duopsony with endogenous location and pricing strategy) face a similar challenge. Their complexity compromises the tractability of conventional equilibrium concepts. In other words, Nash equilibria do not exist, or there is a multiplicity of equilibria. This, in turn, precludes comparative static analyses characterizing the effect of exogenous market forces (uncertainty and firm ownership structure) on market and welfare outcomes.</p> <p><br></p> <p>I address this key challenge through a combination of genetic algorithms and laboratory experiments. A genetic algorithm consists of a selection process that identifies strategies that perform better than others, on average. Therefore, surviving strategies constitute, in a sense, average best responses. More than one strategy may survive. This happens when none of the surviving strategies is weakly dominated by the other surviving strategies. An equilibrium is a combination of surviving strategies. In this context, a comparative static analysis consists of the change in equilibrium (combination of surviving strategies) due to a change in exogenous forces. These comparative static analyses generate testable hypotheses. In Essays 1 and 2, I implement laboratory experiments to test these hypotheses.</p> <p><br></p> <p>In Essay 1, I compare infinitely repeated social dilemmas with deterministic and noisy payoffs. I test whether noise in payoffs (where noisy payoffs are generated by a random shock and are uncorrelated amongst agents), which introduces imperfect monitoring, affects cooperation. Experimental evidence shows that imperfect monitoring reduces cooperation because it hinders agents’ ability to threaten defectors with a reciprocal defection. Therefore, noise reduces efficiency by unraveling cooperation in social dilemmas. In Essay 2, I study whether correlation among agents’ noisy payoffs strengthens monitoring and restores cooperation. Experimental evidence shows that stronger (though still imperfect) monitoring due to correlation helps cooperation if and only if agents are prone to cooperate in the initial rounds of the repeated game. Therefore, correlation among shocks affecting agents’ payoffs may or may not increase efficiency depending on the type of players participating in the social dilemma.</p> <p><br></p> <p>Finally, in Essay 3, I use a genetic algorithm to generate comparative statics characterizing the effect of a cooperative firm on market equilibrium and efficiency in a spatial duoposony. A Nash equilibrium in this setting does not exist when location, price, and the degree of spatial price discrimination are all endogenous in the seminal Hotelling’s model. I use a genetic algorithm to identify a stable equilibrium in this setting. I find that a cooperative firm increases efficiency. But, counterintuitively, it does so when the cooperative does not directly compete with the privately owned firm. This is because the cooperative maximizes market share when its procurement region does not overlap with the privately owned firm’s procurement region.</p> <p><br></p>

[pt] Este trabalho procura entender padrões de busca do consumidor e se fricções informacionais desempenham um papel na dispersão de preços no varejo brasileiro de gasolina. Na nossa abordagem, os consumidores devem se engajar em busca custosa para obter informação sobre os preços cobrados pelos postos de gasolina. Empiricamente, dividimos nossa análise em duas partes. Na primeira, utilizamos um modelo estrutural que nos permite estimar pontos da distribuição dos custos de busca. Estimamos o modelo usando dados de preços no nível do posto para vários mercados no Brasil. Na segunda parte, em duas análises independentes, investigamos os determinantes da proporção de consumidores com baixa quantidade de busca por OLS e construímos uma estimativa para o custo médio de busca por mercado encaixando nossas estimativas pontuais em uma distribuição paramétrica por NLS. Nossas descobertas revelam uma variação significativa na busca do consumidor entre os mercados. Além disso, nossos resultados revelam que a maioria dos consumidores não compara muitos preços antes de comprar gasolina. Ademais, nossas estimativas indicam que o número de postos de gasolina em um mercado, a distância média entre os postos, a renda e a população são fatores importantes para explicar a proporção de consumidores que procuram em apenas um posto antes de comprar. Por fim, o custo médio estimado de busca representa 3 por cento dos preços da gasolina, proporção esta não desprezível. Portanto, os resultados indicam que os atritos de informação são importantes para explicar a dispersão de preços no varejo brasileiro de gasolina. / [en] This paper seeks to understand consumer search patterns and whether information frictions play a role in price dispersion in Brazilian gasoline retail. In our setting, consumers must engage in costly search to gain information about the prices charged by gas stations. Empirically, we divide our analysis into two parts. In the first part, we use a structural model that permits us to estimate points of the distribution of search costs. We estimate the model using price data at the station level for multiple markets in Brazil. In the second part, in two independent analyzes, we investigate the determinants of the proportion of consumers with a low amount of search by OLS and construct an estimate for the average search cost per market by fitting our point estimates into a parametric distribution by NLS. Our findings reveal significant variation in consumer search across markets. Furthermore, our results reveal that most consumers do not compare many prices before buying gasoline. Moreover, our estimates indicate that the number of gas stations in a market, the average distance between gas stations, income, and population are important drivers of the proportion of consumers that search in only one gas station before buying. Finally, the estimated average search cost represents 3 percent of gasoline prices, a non-negligible proportion. Therefore, the results indicate that information frictions are important to explain price dispersion in Brazilian gasoline retail.

No description available.

We study games on graphs, where a coalition of agents work against an adversarial nature to achieve an objective. The agents have to collaborate while making their moves simultaneously, while receiving differing information about the state of the game and without a means of agent-to-agent communication. Before the game starts the coalition agrees on a strategy profile, where each agent is provided with a strategy which it acts in accordance to. The challenge of finding a winning strategy profile, wherein the coalition achieves their objective regardless of any influence from the adversarial nature, is called the strategy synthesis problem. For games with coalitions consisting of more than one agent, the general case of the synthesis problem is undecidable. We formalize an abstraction construction of a game where a subset of agents with predetermined strategies are abstracted into the adversarial nature of another game, for the purpose of reducing the size of the coalition of agents and in turn reduce the complexity of the strategy synthesis problem. We then prove that any winning strategy profile in the new game with fewer agents is also winning in the original game when combined with the predetermined strategies. The most interesting case is reducing a game with a coalition of two agents into a game with a single agent, since the strategy synthesis problem is decidable for games with a single agent. This allows us to test the predetermined strategy of the abstracted agent to see if it is possible to create a winning strategy profile using it. If it is not possible then we can try a different strategy. This enables an iterative approach for solving the strategy synthesis problem instead of a deductive one. / I rapporten studeras spel på grafer där ett lag av agenter samarbetar mot en fientlig omvärld för att uppnå ett mål. Agenterna måste samarbeta och göra sina drag på samma gång trots att de inte kan kommunicera med varandra och att de har olika perspektiv på lagets situation. För att lyckas med detta kommer laget överens om en gemensam strategi som består av en specifik strategi för varje individuell agent. Utmaningen att hitta en vinnande gemensam strategi för laget kallas strategisyntesproblemet och är oavgörbart i det allmänna fallet, det finns bevisat ingen algoritm som löser problemet. Vi formaliserar en abstraktionskonstruktion som tar ett spel där en delmängd av agenterna har blivit tilldelade en strategi för att sedan abstrahera de agenterna in i omvärlden i ett annat spel. Tanken är att i-och-med att agenterna redan har strategier vet vi hur de kommer agera och därmed kan vi se dem som en förutsägbar variabel i det nya spelet vi konstruerar. I det nya spelet har vi då färre agenter att skapa strategier för vilket minskar komplexiteten av strategisyntesproblemet. Vi bevisar också att en vinnande gemensam strategi i det nya spelet kan användas tillsammans med de förbestämda strategierna för att vinna det originella spelet. Det mest intressanta fallet för rapporten är om det originella spelet har två agenter i laget, då det finns algoritmer för att lösa strategisyntesproblemet för ensamma agenter. När en agent abstraheras bort och ett spel med en agent kvarstår betyder det att dessa algoritmer kan appliceras. Om en vinnande strategi hittas har problemet lösts, om inte kan man utesluta de förbestämda strategin som den abstraherade agenten använde. Det möjliggör en iterativ testning och uteslutning av strategier som inte funnits tidigare.

Many real life problems can be modelled using multi-agent games played on finite graphs. When an agent cannot differentiate between game states, for example when a robot operates with a broken sensor, the game is classified as a game of imperfect information. This report focuses on non-deterministic multi-agent games of imperfect information or Multi-Agent Games of Imperfect Information Against Nature (MAGIIAN). Finding optimal strategies for these games is very hard due to the element of imperfect information as well as taking into account the multiple cooperating agents. Using a generalised version for multi-agent games of the known Knowledge Based Subset Construction (KBSC) algorithm may solve the problem of strategy synthesis for MAGIIAN. While the KBSC transforms the game into a game with perfect information, the multi-agent variant (MKBSC) instead yields another MAGIIAN. When applying the algorithm iteratively some games stop expanding while others expand seemingly boundlessly. This is referred to as stability and divergence respectively. Our research focuses on different patterns, called structural conditions, in the MAGIIAN and how they affect stability. By using an existing implementation of the MKBSC along with some newly developed algorithms we were able to iterate over different games and analyse different structural conditions. We have identified several structural conditions which affect stability. By reducing divergent games to only their core components with respect to divergence, a more careful examination of what causes divergence could be done. It reaffirmed earlier research that cycles are necessary in order for games to diverge. Observation overlap was found to not be a necessary condition for divergent games as counter examples to this was found. Games containing well formed observations were found to stabilise within one iteration. Our research has also lead us to believe that it is impossible for structural conditions to properly classify divergence. / Olika typer av autonoma problem kan modelleras med hjälp av fleragentsspel spelade på ändliga grafer. Spel där en agent ej kan urskilja mellan två tillstånd, till exempel när en robot arbetar med trasiga sensorer, klassas som spel med ofullständig information. Vår rapport fokuserar på ickedeterministiska fleragentsspel med ofullständig information, även kallat Multi-Agent Games of Imperfect Information Against Nature (MAGIIAN). Att hitta optimala strategier för dessa spel är mycket svårt både på grund av den ofullständiga informationen och på grund av flertalet agenter som ska samarbeta. Användandet av en generaliserad variant för fleragentspel av den kända Knowledge Based Subset Construction (KBSC) algoritmen kan hjälpa att hitta vinnande strategier för MAGIIAN. Medan KBSC algoritmen transformerar spelet till ett spel med fullständig information, så ger fleragentsvarianten istället ännu ett MAGIIAN. Om man applicerar algoritmen många gånger kommer vissa spel sluta att växa medan andra fortsätter växa gränslöst. Detta kallas att spelen är stabila eller divergeranta. Vår rapport fokuserar på olika strukturer i dessa spel och hur dessa påverkar stabiliteten. Genom att använda en implementation av MKBSC tillsammans med nya algoritmer har vi itererat över många olika spel och analyserat olika strukturer. Vi har hittat flertalet strukturer som påverkar stabiliteten. Genom att reducera divergenta spel så att alla kvarvarande komponenter krävs för divergens, kunde divergenses orsaker noggrannt undersökas. Detta bekräftade tidigare påståenden om att cykler krävs för divergens. Därefter motbevisades att överlappande observationer krävdes för divergens med hjälp av motexempel. Spel innehållandes välformade observationer visades stabilisera efter en iteration av MKBSC:n.