Ambiguity helps: classification with disagreements in crowdsourced annotations

Imagine we show an image to a person and ask her/him to decide whether the scene in the image is warm or not warm, and whether it is easy or not to spot a squirrel in the image. For exactly the same image, the answers to those questions are likely to differ from person to person. This is because the task is inherently ambiguous. Such an ambiguous, therefore challenging, task is pushing the boundary of computer vision in showing what can and can not be learned from visual data. Crowdsourcing has been invaluable for collecting annotations. This is particularly so for a task that goes beyond a clear-cut dichotomy as multiple human judgments per image are needed to reach a consensus. This paper makes conceptual and technical contributions. On the conceptual side, we define disagreements among annotators as privileged information about the data instance. On the technical side, we propose a framework to incorporate annotation disagreements into the classifiers. The proposed framework is simple, relatively fast, and outperforms classifiers that do not take into account the disagreements, especially if tested on high confidence annotations

Composição centesimal da castanha-do-brasil (Bertholletia excelsa) comercializada em Macapá e Santana (AP).

O objetivo deste trabalho foi avaliar o valor nutritivo através da composição centesimal da amêndoa da castanha-do-brasil comercializada nas quatro principais feiras dos municípios de Macapá e Santana oriundas das reservas de Iratapuru, Cajari e Maracá

Cluster Structures with Machine Learning Support in Neutron Star M-R relations

Neutron stars (NS) are compact objects with strong gravitational fields, and a matter composition subject to extreme physical conditions. The properties of strongly interacting matter at ultra-high densities and temperatures impose a big challenge to our understanding and modelling tools. Some difficulties are critical, since one cannot reproduce such conditions in our laboratories or assess them purely from astronomical observations. The information we have about neutron star interiors are often extracted indirectly, e.g., from the star mass-radius relation. The mass and radius are global quantities and still have a significant uncertainty, which leads to great variability in studying the micro-physics of the neutron star interior. This leaves open many questions in nuclear astrophysics and the suitable equation of state (EoS) of NS. Recently, new observations appear to constrain the mass-radius and consequently has helped to close some open questions. In this work, utilizing modern machine learning techniques, we analyze the NS mass-radius (M-R) relationship for a set of EoS containing a variety of physical models. Our objective is to determine patterns through the M-R data analysis and develop tools to understand the EoS of neutron stars in forthcoming works.Comment: Contribution to the XLIV Brazilian Workshop on Nuclear Physics, Brazi

Stellar equilibrium configurations of white dwarfs in the f(R,T)f(R,T) gravity

In this work we investigate the equilibrium configurations of white dwarfs in a modified gravity theory, na\-mely, $f(R,T)$ gravity, for which $R$ and $T$ stand for the Ricci scalar and trace of the energy-momentum tensor, respectively. Considering the functional form $f(R,T)=R+2\lambda T$, with $\lambda$ being a constant, we obtain the hydrostatic equilibrium equation for the theory. Some physical properties of white dwarfs, such as: mass, radius, pressure and energy density, as well as their dependence on the parameter $\lambda$ are derived. More massive and larger white dwarfs are found for negative values of $\lambda$ when it decreases. The equilibrium configurations predict a maximum mass limit for white dwarfs slightly above the Chandrasekhar limit, with larger radii and lower central densities when compared to standard gravity outcomes. The most important effect of $f(R,T)$ theory for massive white dwarfs is the increase of the radius in comparison with GR and also $f(R)$ results. By comparing our results with some observational data of massive white dwarfs we also find a lower limit for $\lambda$, namely, $\lambda >- 3\times 10^{-4}$.Comment: To be published in EPJ

Produtos e subprodutos da castanha-do-brasil no Estado do Amapá.

A castanha-do-brasil é uma espécie nativa da Amazônia, com ampla distribuição, sendo uma das mais nobres e valiosas da floresta, devido ao seu aproveitamento tanto em termos madereiros como também de seus frutos. Participando na dieta alimentar em várias regiões do Amazonas. O presente documento foi elaborado visando apresentar informações à população, principalmente em termos de composição das vitaminas, minerais e seus óleos essenciais, não apenas em termos quantitativos, mas também em termos qualitativos, que é o enfoque mais moderno nos principais estudos mundiais.bitstream/item/71202/1/AP-2001-produtos-subprodutos-castanha-do-brasil.pd

Avaliação das características químicas do vinho de açaí comercializado em Macapá e Santana (AP).

A bebida proveniente do fruto do açaizeiro, conhecido como vinho, representa item básico na alimentação da população amapaense, estimando-se um consumo médio diário de 27 mil a 34 mil L/dia somente na capital Macapá. Este trabalho teve por objetivo analisar alguns componentes químicos do vinho de açaí, comercializado em quatro pontos distintos dos principais municípios consumidores, de Macapá e Santana (AP), e originados de diferentes locais de coleta dos frutos, com intervalos de tempo entre coleta e processamento distintos. As amostras foram transportadas ao Laboratório de Alimentos da Embrapa Amapá, em recipientes estéreis, onde realizaram-se as avaliações do teor de umidade, sendo a matéria seca determinada por diferença; pH, extrato etéreo (Iipídeos) e da proteína bruta. As amostras de vinho de açaí adquiridas enquadraram-se nos padrões físico-químicos disponíveis na literatura, apresentando-se como alimento altamente calórico com média de 7,1% de lipídeos, mas não podendo ser considerada uma fonte proteica única, pois apresentou teor de 2,1% de proteína bruta, devendo ser ingerida com alimentação complementar

Avaliação físico-química da água de coco-anão cultivado no Estado do Amapá.

Publicado também em: FRAZÃO, D. A. C.; HOMMA, A. K. O; VIÉGAS, I. de J. M. (Ed.). Contribuição ao desenvolvimento da fruticultura na Amazônia. Belém, PA: Embrapa Amazônia Oriental, 2006. p. 349-354

GRB 170817A-GW170817-AT 2017gfo and the observations of NS-NS, NS-WD and WD-WD mergers

The LIGO-Virgo Collaboration has announced the detection of GW170817 and has associated it with GRB 170817A. These signals have been followed after 11 hours by the optical and infrared emission of AT 2017gfo. The origin of this complex phenomenon has been attributed to a neutron star-neutron star (NS-NS) merger. In order to probe this association we confront our current understanding of the gravitational waves and associated electromagnetic radiation with four observed GRBs originating in binaries composed of different combinations NSs and white dwarfs (WDs). We consider 1) GRB 090510 the prototype of NS-NS merger leading to a black hole (BH); 2) GRB 130603B the prototype of a NS-NS merger leading to massive NS (MNS) with an associated kilonova; 3) GRB 060614 the prototype of a NS-WD merger leading to a MNS with an associated kilonova candidate; 4) GRB 170817A the prototype of a WD-WD merger leading to massive WD with an associated AT 2017gfo-like emission. None of these systems support the above mentioned association. The clear association between GRB 170817A and AT 2017gfo has led to introduce a new model based on on a new subfamily of GRBs originating from WD-WD mergers. We show how this novel model is in agreement with the exceptional observations in the optical, infrared, X- and gamma-rays of GRB 170817A-AT 2017gfo.Comment: version accepted for publication in JCAP. Missing references adde