Data driven and physics based methods to assess the mechanical response of advanced materials: from experiments to efficient predictions

L'abstract è presente nell'allegato / the abstract is in the attachmen

Hoaxy: A Platform for Tracking Online Misinformation

Massive amounts of misinformation have been observed to spread in uncontrolled fashion across social media. Examples include rumors, hoaxes, fake news, and conspiracy theories. At the same time, several journalistic organizations devote significant efforts to high-quality fact checking of online claims. The resulting information cascades contain instances of both accurate and inaccurate information, unfold over multiple time scales, and often reach audiences of considerable size. All these factors pose challenges for the study of the social dynamics of online news sharing. Here we introduce Hoaxy, a platform for the collection, detection, and analysis of online misinformation and its related fact-checking efforts. We discuss the design of the platform and present a preliminary analysis of a sample of public tweets containing both fake news and fact checking. We find that, in the aggregate, the sharing of fact-checking content typically lags that of misinformation by 10--20 hours. Moreover, fake news are dominated by very active users, while fact checking is a more grass-roots activity. With the increasing risks connected to massive online misinformation, social news observatories have the potential to help researchers, journalists, and the general public understand the dynamics of real and fake news sharing.Comment: 6 pages, 6 figures, submitted to Third Workshop on Social News On the We

(De)Fencing the Cultural Commons Through a (De)Constructive Media Art Curriculum

Rampant consolidation in the media industry has led to an ever-increasing push to extend the breadth and scope of copyright law. A deliberate and systematic effort to restrict access to cultural texts that were previously accessible has led to a creative climate that is increasingly intimidating to young artists. The personal computer provides students the ability to re-open these texts and reclaim their right to fairly use the cultural artifacts of their surroundings as building blocks of expression. The personal computer can deconstruct closed media texts into malleable parts of visual language that students can reconstruct into new texts. These new texts have the potential to transgress the cultural demarcation erected by big media’s successful lobbying of the US Senate for restrictive copyright legislation

How algorithmic popularity bias hinders or promotes quality

Algorithms that favor popular items are used to help us select among many choices, from engaging articles on a social media news feed to songs and books that others have purchased, and from top-raked search engine results to highly-cited scientific papers. The goal of these algorithms is to identify high-quality items such as reliable news, beautiful movies, prestigious information sources, and important discoveries --- in short, high-quality content should rank at the top. Prior work has shown that choosing what is popular may amplify random fluctuations and ultimately lead to sub-optimal rankings. Nonetheless, it is often assumed that recommending what is popular will help high-quality content "bubble up" in practice. Here we identify the conditions in which popularity may be a viable proxy for quality content by studying a simple model of cultural market endowed with an intrinsic notion of quality. A parameter representing the cognitive cost of exploration controls the critical trade-off between quality and popularity. We find a regime of intermediate exploration cost where an optimal balance exists, such that choosing what is popular actually promotes high-quality items to the top. Outside of these limits, however, popularity bias is more likely to hinder quality. These findings clarify the effects of algorithmic popularity bias on quality outcomes, and may inform the design of more principled mechanisms for techno-social cultural markets

Finding Streams in Knowledge Graphs to Support Fact Checking

The volume and velocity of information that gets generated online limits current journalistic practices to fact-check claims at the same rate. Computational approaches for fact checking may be the key to help mitigate the risks of massive misinformation spread. Such approaches can be designed to not only be scalable and effective at assessing veracity of dubious claims, but also to boost a human fact checker's productivity by surfacing relevant facts and patterns to aid their analysis. To this end, we present a novel, unsupervised network-flow based approach to determine the truthfulness of a statement of fact expressed in the form of a (subject, predicate, object) triple. We view a knowledge graph of background information about real-world entities as a flow network, and knowledge as a fluid, abstract commodity. We show that computational fact checking of such a triple then amounts to finding a "knowledge stream" that emanates from the subject node and flows toward the object node through paths connecting them. Evaluation on a range of real-world and hand-crafted datasets of facts related to entertainment, business, sports, geography and more reveals that this network-flow model can be very effective in discerning true statements from false ones, outperforming existing algorithms on many test cases. Moreover, the model is expressive in its ability to automatically discover several useful path patterns and surface relevant facts that may help a human fact checker corroborate or refute a claim.Comment: Extended version of the paper in proceedings of ICDM 201

Resposta a Vilanova Artigas. Por uma sede própria.

Um dos atributos que fizeram do Edifício IAB um objeto singular é o modelo raro, senão único, de edificação do porte e tipologia erguida por e para seus usuários em favor de uma causa. Isso porque, em 1943, quando o Departamento Paulista do Instituto de Arquitetos do Brasil é instalado, institucionaliza-se uma agenda ímpar cujo mérito foi unir a classe por uma nova arquitetura a exemplo do grupo do Rio de Janeiro reconhecido internacionalmente. Todavia, o não aprofundamento acerca do papel desempenhado pela seção paulista do instituto, na implementação das tendências de vanguarda, está a comprometer o reconhecimento crítico da relação entre a sua fundação e a renovação da arquitetura produzida na cidade simbolizada no próprio edifício-sede inaugurado em 1950. Logo, identificar o ora nomeado Movimento IABsp e seus seguidores pode aprimorar os critérios de análise e crítica no campo da prática arquitetônica à época da gestão de Eduardo Kneese de Mello à frente do instituto (1943-1950). Nascido em resposta a Vilanova Artigas, que durante um ciclo de depoimentos questionou o anonimato de seus pares engajados na ação coletiva, este artigo não entra no mérito do objeto arquitetônico, propriamente dito, tombado pelo Instituto do Patrimônio Histórico e Artístico (IPHAN), em 2015.One of the atributes that made the IAB-São Paulo Building a singular object is the rare, if not unique, model of designing a size and typology raised by and for their users in favor of a cause. This happened because, in 1943, when the Paulista Department of the Institute of Architects of Brazil was organized, an unprecedented movement was also launched. Its merit was to unite the professional class around renovation the architecture, similar to the internationally recognized Rio de Janeiro’s group. However, the lack of a specific study about the role the Department played in the implementing of avant-garde trends compromises the critical recognition of the relationship between the Paulista class and the change of architecture produced in the city, symbolized in the IAB-SP building itself, opened in 1950. Therefore, identifying the now named Movement IABsp and its followers, can improve the criteria of analysis and criticism about the local architectural practice during Eduardo Kneese de Mello’s administration at the institut (1943-1950). In response to Vilanova Artigas who, during a series of personal testimonies questioned the anonymity of his peers who engaged with him in the collective action, this article does not detach the merits of the IAB-SP building itself, listed by the National Institute for Historic and Artistic Heritage (IPHAN), in 2015

Earnings management and the relation with cost of debt of Brazilian public companies

Sob a teoria de agência e as premissas de gerenciamento de resultados, o objetivo do trabalho foi estudar a relação entre o gerenciamento de resultados (GR) e o custo da dívida (Ki) das empresas brasileiras abertas, no período de 1996 a 2007. Os pressupostos levantados, por meio da literatura existente, são de que, almejando melhores condições contratuais, como o custo da dívida, o custo atual ou passado motiva a empresa a gerenciar o resultado corrente para obter melhores condições de custo futuro ou corrente. Dessa forma, as empresas, intencionalmente, procurariam gerenciar seus resultados, motivadas pelo custo da dívida. Todavia, há apoio teórico para que a relação entre essas variáveis seja unidirecional, com o GR influenciando o custo da dívida, sustentando a segunda hipótese. Para chegar ao objetivo, o trabalho utilizou, como proxy de GR, o modelo para cálculo dos accruals discricionários proposto por Kang e Sivaramakrishnan (1995). As análises foram baseadas no teste não-paramétrico U de Mann-Whitney, seguidas do teste de especificação de Hausman para a análise de simultaneidade, finalizando com a regressão com dados dispostos em painel com correção de Newey-West. Os testes de média apontaram para uma relação positiva entre GR e Ki, mas o teste de simultaneidade não indicou haver inter-relação entre as variáveis. Contudo, os resultados das regressões em painel indicaram que o Ki não influencia o GR, mas que há uma relação positiva, em que quanto maior o GR, maior o custo da dívida, ou seja, este é influenciado por aquele.Under agency theory and assumptions of earnings management, the objective is to study the relationship between earnings management (EM) and the cost of debt (Ki) of Brazilian publicly held companies in the period from 1996 to 2007. The assumptions raised through the literature are that targeting better contractual terms, like cost of debt, current or past cost, motivates the company to manage the current result so as to obtain better conditions for current or future cost. Thus, companies, intentionally, would seek to manage their results, motivated by the cost of debt. However, theoretical support for the relationship between these variables would be unidirectional, with EM influencing the cost of debt, supporting the second hypothesis. To reach the objective, the work used the EM model for the discretionary accruals proposed by Kang and Sivaramakrishnan (1995) as a proxy. The tests were based on Mann-Whitney's, nonparametric U test, followed by the Hausman specification test for simultaneity analysis, ending with regression with panel data arranged with Newey-West correction. Tests showed the average for a positive relationship between EM and Ki, but the test did not indicate that there is a simultaneous inter-relationship between variables. The results of the panel regression indicates that Ki does not influence EM, but there is a positive relationship between them, in which the higher the EM, the higher the Ki

Hemoglobinopatias e sua relação com doenças da cavidade oral: revisão narrativa

As hemoglobinopatias estão entre as doenças hereditárias mais comuns em todo o mundo. Consistem em alterações genéticas que afetam a estrutura ou a produção normal da hemoglobina. As hemoglobinopatias podem ser divididas em dois grupos principais: as que provocam alterações quantitativas, isto é, envolvem um desequilíbrio no número de cadeias de globina, e aquelas cujas alterações provocam distúrbios qualitativos, que resultam em alterações estruturais na molécula de hemoglobina. Alterações quantitativas da hemoglobina resultam em talassemias, enquanto os defeitos qualitativos estão associados por exemplo a anemia falciforme. Enquanto algumas formas leves de talassemia podem passar despercebidas e causar apenas anemia leve e problemas de deficiência de ferro, existem outras formas mais graves. As principais manifestações orais da talassemia são má oclusão, protrusão maxilar, alto índice de cárie e gengivite severa. A anemia falciforme resulta de glóbulos vermelhos com forma anormal e função alterada, sendo a principal característica clínica a anemia hemolítica. As complicações agudas são frequentes e variáveis e incluem síndrome torácica, acidente vascular cerebral, infeções e dor óssea. Outras complicações crónicas que podem ocorrer são necrose óssea, nefropatia e distúrbios cardíacos, pulmonares e cutâneos. As lesões orais também são muito comuns e incluem necrose asséptica da polpa, danos na mucosa devido a anemia, atrasos na erupção dentária, dor óssea e osteomielite da maxila e neuropatias orais. A higiene oral neste tipo de pacientes requer cuidados específicos e um acompanhamento regular.Hemoglobinopathies are among the most common hereditary diseases worldwide. They consist of genetic alterations that affect the normal structure or production of hemoglobin. Hemoglobinopathies can be divided into two main groups: those in which the genetic alterations cause quantitative changes, involving an imbalance in the number of globin chains, and those whose genetic change causes qualitative disorders, which result in changes in hemoglobin structure. Quantitative changes in hemoglobin result in thalassemia, while qualitative defects are associated, for example, with sickle cell anemia. While some mild forms of thalassemia can go undetected and cause only mild anemia and iron deficiency problems, there are other more serious forms. The main oral manifestations of thalassemia are malocclusion, maxillary protrusion, high caries rate and severe gingivitis. Sickle cell anemia results from abnormally shaped red blood cells with altered function, the main clinical feature being hemolytic anemia. Acute complications are frequent and variable and include chest syndrome, stroke, infections, and bone pain. Other chronic complications that may occur are bone necrosis, nephropathy, and heart, lung, and skin disorders. Oral lesions are also very common and include aseptic pulp necrosis, mucosal damage due to anemia, delayed tooth eruption, bone pain and osteomyelitis of the jaw, and oral neuropathies. In patients having this type of disease, oral hygiene requires specific care and regular monitoring