Emergence of skyrmion lattices and bimerons in chiral magnetic thin films with nonmagnetic impurities

Skyrmions are topologically protected field structures with particlelike characteristics that play important roles in several areas of science. Recently, skyrmions have been directly observed in chiral magnets. Here, we investigate the effects of pointlike nonmagnetic impurities on the distinct initial states (random or helical ones) and on the formation of the skyrmion crystal in a discrete lattice. Using Monte Carlo techniques, we have found that even a small percentage of spin vacancies present in the chiral magnetic thin film considerably affects the skyrmion order. The main effects of impurities are somewhat similar to thermal effects. The presence of these spin vacancies also induces the formation of bimerons in both the helical and skyrmion states. We also investigate how adjacent impurities forming a hole affect the skyrmion crystal

New sequential optimality conditions for mathematical programs with complementarity constraints and algorithmic consequences

In recent years, the theoretical convergence of iterative methods for solving nonlinearnconstrained optimization problems has been addressed using sequential optimality conditions, which are satisfied by minimizers independently of constraint qualifications (CQs). Even though there is a considerable literature devoted to sequential conditions for standard nonlinear optimization, the same is not true for mathematical programs with complementarity constraints (MPCCs). In this paper, we show that the established sequential optimality conditions are not suitable for the analysis of convergence of algorithms for MPCC. We then propose new sequential optimality conditions for usual stationarity concepts for MPCC, namely, weak, Clarke, and Mordukhovich stationarity. We call these conditions AW-, AC-, and AM-stationarity, respectively. The weakest MPCC-tailored CQs associated with them are also provided. We show that some of the existing methods for MPCC reach AC-stationary points, extending previous convergence results. In particular, the new results include the linear case, not previously covered.29432013230CNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo301888/2017-5; 306986/2016- 7; 302915/2016-82013/07375-0; 2013/05475-7; 2017/18308-

A produção acadêmica sobre a Agência Nacional de Saúde Suplementar: um olhar a partir da Biblioteca Digital Brasileira de Teses e Dissertações

National Regulatory Agency for Private Health Insurance and Plans (ANS) is the regulatory agency linked to Ministry of Health, which is responsible for health insurance in Brazil. Although it was established in 2000, there is already a considerable number of production studies about the Agency, it is relevant to know what these researches cover. This literature review article aimed at analyzing academic production about the ANS, found on Brazilian Digital Library of Theses and Dissertations. It is a qualitative research that uses the technique of thematic content analysis. All studies in that library that address the ANS were examined. For bibliographic material selection, selecting a specific period was not needed. Only theses and dissertations that included “National Regulatory Agency for Private Health Insurance and Plans” expression in any of the search fields available were analyzed. It was possible to identify the main existing issues covered by these academic productions: economic regulation, political and legal aspects of regulation and health-related characteristics of regulation; similarities and differences of understanding such regulatory institution were also discussed. We concluded that the identified issues don’t exclude each other, on the contrary, they are complementary and indicate the different facets of the institution. Furthermore, analysis of academic production unearthed differences of understanding regarding the Agency, sometimes seen as conciliation proceedings, sometimes considered as a bureaucratic and slow institution, but also seen as an institution that encourages promotion practices to health, disease prevention and improved health quality.A Agência Nacional de Saúde Suplementar (ANS) é a agência reguladora vinculada ao Ministério da Saúde, e responsável pelo setor de planos de saúde no Brasil. Embora tenha sido criada no ano de 2000, já existe considerável produção de estudos sobre a Agência, sendo pertinente conhecer o que abordam essas pesquisas. Nesta perspectiva, este artigo de revisão bibliográfica buscou analisar a produção acadêmica sobre a ANS existente na Biblioteca Digital Brasileira de Teses e Dissertações. Trata-se de pesquisa qualitativa que utiliza a técnica análise de conteúdo temática. Todos os estudos presentes na Biblioteca que abordem a ANS foram examinados. Para a seleção do material bibliográfico não foi realizado recorte temporal. Foram incluídas as teses e dissertações que apresentaram a expressão “Agência Nacional de Saúde Suplementar” em quaisquer dos campos de busca disponíveis. Foi possível identificar os principais temas existentes nestas produções acadêmicas: aspectos econômicos da regulação, aspectos político-jurídicos da regulação e aspectos relacionados à saúde da regulação; também foram discutidas as semelhanças e as diferenças de compreensão em relação à referida instituição reguladora. Concluiu-se que os temas identificados não se excluem, ao contrário, são complementares, indicando as diferentes facetas da instituição estudada. Além disso, a análise da produção acadêmica permitiu revelar diferenças de compreensão em relação à Agência, ora vista como instância de conciliação, ora considerada órgão burocrático e lento, e também como instituição que incentiva práticas de promoção à saúde e prevenção de doenças e melhoria da qualidade em saúde