Born-Infeld magnetars: larger than classical toroidal magnetic fields and implications for gravitational-wave astronomy

Magnetars are neutron stars presenting bursts and outbursts of X- and soft-gamma rays that can be understood with the presence of very large magnetic fields. Thus, nonlinear electrodynamics should be taken into account for a more accurate description of such compact systems. We study that in the context of ideal magnetohydrodynamics and make a realization of our analysis to the case of the well-known Born-Infeld (BI) electromagnetism in order to come up with some of its astrophysical consequences. We focus here on toroidal magnetic fields as motivated by already known magnetars with low dipolar magnetic fields and their expected relevance in highly magnetized stars. We show that BI electrodynamics leads to larger toroidal magnetic fields when compared to Maxwell's electrodynamics. Hence, one should expect higher production of gravitational waves (GWs) and even more energetic giant flares from nonlinear stars. Given current constraints on BI's scale field, giant flare energetics and magnetic fields in magnetars, we also find that the maximum magnitude of magnetar ellipticities should be $10^{-6}-10^{-5}$. Besides, BI electrodynamics may lead to a maximum increase of order $10\%-20\%$ of the GW energy radiated from a magnetar when compared to Maxwell's, while much larger percentages may arise for other physically motivated scenarios. Thus, nonlinear theories of the electromagnetism might also be probed in the near future with the improvement of GW detectors.Comment: 8 pages, no figures, accepted for publication in The European Physical Journal C (EPJC

Uso de imagem de pessoas, silhuetas e marcas [direitos autorais]

Aborda os principais cuidados para a utilização de imagens de pessoas, silhuetas e marcas. Vídeo da atividade 3, unidade 3, do Curso de Direitos Autorais, ofertado pela Universidade Aberta do SU

Obra anônima, pseudônima e obras colocadas em logradouro público [direitos autorais]

Especialistas apresentam o que são e como funciona o uso de obras anônimas e pseudônimas, e obras colocadas em logradouro público. Vídeo da atividade 7, unidade 1, do Curso de Direitos Autorais, ofertado pela Universidade Aberta do SU

MECHANISM FOR CROSS PROCESS COMMUNICATION WITH ANR CHECKING AND AUTOMATIC OBJECT SERIALIZATION

A host and a client may perform inter-process communication (IPC) with automatic object serialization and deserialization and with application not responding (ANR) checking. A sender (e.g., a host process, host application, host device, a client process, client application, client device, etc.) may automatically serialize an object by using reflection (e.g., the ability of a process to examine, introspect, and modify its own structure and behavior) to recursively obtain all fields and corresponding key-value pairs from each layer of the object (as well as any parent object with inheritance). The sender may bundle the fields and key-value pairs and transmit the bundle to a receiver (e.g., the client if the host is the sender, the host if the client is the sender, etc.) via a network. The receiver may examine the bundle and determine the type of the object (e.g., arrays, string classes, interfaces, etc.) based on the fields and/or the key-value pairs stored in the bundle. The receiver may then implement the appropriate process for reconstructing the object from the based on the fields and the corresponding key-pairs. This serialization and deserialization process may be performed for each communication transmitted between the sender and the receiver. Additionally or alternatively, when the sender communicates with the receiver, the sender may send a message via a binder that causes the receiver to send a generic callback to the sender. In some examples, if the sender does not receive the callback before a predetermined period expires (e.g., the call timed-out), the sender may output a notification that the receiver (e.g., the application executing at the receiver) is not responding. In this way, the binder may provide ANR checking that informs the user whether an error has occurred or not

Impacto de la condición periodontal para individuos con COVID-19.

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Comparação entre as modalidades de usucapião no código civil e suas vantagens ou desvantagens para o indivíduo e os direitos envolvidos

Trabalho de Conclusão de Curso (Graduação)O presente trabalho busca estudar a relação entre a usucapião e o direito de propriedade. O estudo passa desde a análise da usucapião Romana, passando pelas ordenações e pelo código de 1916. Estudar-se-á, também, as modalidades existentes no ordenamento atual, seus requisitos e procedimento, além das teorias de posse. Assim, verá-se a importância deste instituto para a própria estabilidade no direito de propriedade, por impedir que disputas pela propriedade retroajam para tempos imemoriais, com o objetivo de verificar possíveis vícios na propriedade, isto ocorre, pois, a usucapião é uma forma originária de adquirir propriedade tornando irrelevante vícios anteriores

Gibbs Measures on Multidimensional Spaces. Equivalences and a Groupoid Approach

We consider some of the main notions of Gibbs measures on subshifts introduced by different communities, such as dynamical systems, probability, operator algebras, and mathematical physics. For potentials with $d$-summable variation, we prove that several of the definitions considered by these communities are equivalent. In particular, when the subshift is of finite type (SFT), we show that all definitions coincide. In addition, we introduced a groupoid approach to describe some Gibbs measures, allowing us to show the equivalence between Gibbs measures and KMS states (the quantum analogous to the Gibbs measures).Comment: arXiv admin note: text overlap with arXiv:2008.1372

Arterial pressure control for nursing military professionals

Objective: Determine which risks factors for hypertension that military nursing professionals identify in their lifestyle; classifying blood pressure levels of professionals. Method: Quantitative, based on descriptive research. Results: This study included 40 military professionals in nursing. The following risks factors were identified for hypertension in the study population: using of hormonal contraceptives (8.0%), smoking (7.0%), alcoholic beverages (2.0%), physical inactivity (21.0%), stress (25.0%), excessive salt intake (11.0%), obesity (8.0%) and high calorie and high protein diet (18.0%). The classification of blood pressure of the subjects revealed that 70.0% showed pressure values considered normal or optimal, values between 12.5% and 17.5 % were considered borderline hypertensions prove. Conclusion: This study indicates the needs for changes in professionals’ lifestyle, because the risks factors associated with blood pressure levels may contribute to the onset of hypertension into analyzed population

Aplicação de Técnicas de Inteligência Computacional para Detecção de Fraude em Comércio Eletrônico

O volume de transações eletrônicas cresceu significativamente nosúltimos anos, devido principalmente à popularização dos serviços de comer-cio eletrônico. Com essa popularização aumentou consideravelmente os casosde fraudes, resultando assim em um prejuízo de bilhões de dólares em todoo mundo. Assim, é necessário prover mecanismos capazes de auxiliar na de-tecção de fraude, foco principal deste projeto de pesquisa. Este trabalho deiniciação científica visa a modelagem e aplicação de técnicas de inteligênciacomputacional para detectar fraudes em transações eletrônicas, mais especifi-camente em operações envolvendo cartão de crédito, utilizando as técnicas deRegressão Logística e Redes Bayesianas. Para avaliar a eficácia das técnicas,definimos o conceito de Eficiência Econômica e o aplicamos a um cenário realdo serviço de pagamento eletrônico mais popular do Brasil. Nossos resulta-dos apresentaram bom desempenho para detecção de fraude, com um ganho de35,61% em relação ao cenário real da empresa