The dynamics of rings around Centaurs and Trans-Neptunian Objects

Since 2013, dense and narrow rings are known around the small Centaur object Chariklo and the dwarf planet Haumea. Dense material has also been detected around the Centaur Chiron, although its nature is debated. This is the first time ever that rings are observed elsewhere than around the giant planets, suggesting that those features are more common than previously thought. The origins of those rings remain unclear. In particular, it is not known if the same generic process can explain the presence of material around Chariklo, Chiron, Haumea, or if each object has a very different history. Nonetheless, a specific aspect of small bodies is that they may possess a non-axisymmetric shape (topographic features and or elongation) that are essentially absent in giant planets. This creates strong resonances between the spin rate of the object and the mean motion of ring particles. In particular, Lindblad-type resonances tend to clear the region around the corotation (or synchronous) orbit, where the particles orbital period matches that of the body. Whatever the origin of the ring is, modest topographic features or elongations of Chariklo and Haumea explain why their rings should be found beyond the outermost 1/2 resonance, where the particles complete one revolution while the body completes two rotations. Comparison of the resonant locations relative to the Roche limit of the body shows that fast rotators are favored for being surrounded by rings. We discuss in more details the phase portraits of the 1/2 and 1/3 resonances, and the consequences of a ring presence on satellite formation.Comment: Chapter to be published in the book "The Transneptunian Solar System", Dina Prialnik, Maria Antonietta Barucci, Leslie Young Eds. Elsevie

A Killing Disease Epidemic Among Displaced Sudanese Population Identified as Visceral Leishmaniasis.

A fatal disease epidemic affected the Bentiu area in southern Sudan and led to a mass migration of the Nuer tribe searching for treatment. The initially available information revealed a high mortality rate due to a possible occurrence of tuberculosis, malaria, enteric fever or visceral leishmaniasis (VL). Serological screening of 53 of the most severely affected patients in an enzyme-linked immunosorbent assay (ELISA) or an improved direct agglutination test (DAT) revealed positivity for VL. In 39 of those patients, diagnosis was confirmed by identification of Leishmania donovani amastigotes in lymph node or bone-marrow aspirates. In a total of 2714 patients observed, 1195 (44.0%) had clinical symptoms suggesting VL: DAT positive titers (1:3200-greater than or equal to 1:12800) were obtained in 654 (24.1%), of whom 325 were confirmed parasitologically. Forty-two VL cases died before or during treatment, giving a mortality rate of 6.4%. Among the intercurrent infections diagnosed in the VL population (654), respiratory involvements (31.7%) and malaria (10.7%) were most prevalent. With the exception of four (0.6%), all other VL patients (509) responded readily to sodium stibogluconate. The factors initiating the outbreak are discussed. Malnutrition and nomadic movements to potential VL endemic areas appeared to be the most important. HIV infection as a possible predisposition seemed remote considering the clinical and epidemiological similarity to VL occurring in East Africa, adequate humoral response in DAT, and immediate positive response to specific anti-Leishmania chemotherapy

Interaction of Phonons and Dirac Fermions on the Surface of Bi2Se3: A Strong Kohn Anomaly

We report the first measurements of phonon dispersion curves on the (001) surface of the strong three-dimensional topological insulator Bi2Se3. The surface phonon measurements were carried out with the aid of coherent helium beam surface scattering techniques. The results reveal a prominent signature of the exotic metallic Dirac fermion quasi-particles, including a strong Kohn anomaly. The signature is manifest in a low energy isotropic convex dispersive surface phonon branch with a frequency maximum of 1.8 THz, and having a V-shaped minimum at approximately 2kF that defines the Kohn anomaly. Theoretical analysis attributes this dispersive profile to the renormalization of the surface phonon excitations by the surface Dirac fermions. The contribution of the Dirac fermions to this renormalization is derived in terms of a Coulomb-type perturbation model

Hepatite B: considerações epidemiológicas, imunológicas e sorológicas com ênfase em mutação

The global prevalence of hepatitis B virus is estimated to be 350 million chronic carriers, varying widely from low (;8% as in Africa, Southeast Asia, and China). The overall prevalence in Brazil is about 8%. There are currently 7 genotypic variations, from A to G, and also 4 main surface antigen subtypes: adw, ayw, adr, and ayr. There has been great interest in identifying the geographic distribution and prognosis associated with the various genotypes and subtypes. Although the serologic test is highly sensitive and specific, it does not detect cases of mutant hepatitis B, which is increasingly common worldwide due to resistance and vaccine escape, antiviral therapy, and immunosuppression, among other causes. Alterations in surface, polymerase, X region, core, and precore genes have been described. The main mutations occur in surface and in core/precore genes, also known as occult hepatitis, since its serologic markers of active infection (HBsAg) and viral replication (HBeAg) can be negative. Thus, mutation should be suspected when serologic tests to hepatitis B show control of immunity or replication coincident with worsened clinical status and exclusion of other causes of hepatitis.A prevalência mundial do vírus da Hepatite B é estimada em cerca 350 milhões de infectados cronicamente, tendo distribuição bastante variada com prevalências baixas desde inferiores a dois por cento, como Europa Ocidental, América do Norte, Nova Zelândia, Austrália e Japão - até altas, superiores a oito por cento como encontradas na África, Sudeste Asiático e China. No Brasil, a prevalência média é em torno de 8%. São descritos atualmente sete variações genotípicas do HBV, nomeadas de A a G, e quatro subtipos principais de antígenos de superfície: "adw", "ayw", "adr "e "ayr", existindo um grande interesse em identificar quais os subtipos e genotipos mais prevalentes a fim de correlacioná-los com manifestações clínicas e distribuição geográfica. Apesar do diagnóstico sorológico ser normalmente bastante sensível e específico, este não detecta casos de Hepatite B mutantes, cada vez mais freqüentes atualmente devido a escape e resistência de vacinação, terapias anti-virais, imunossupressão dentre outras. São descritas alterações genômicas no gene de superfície (envelope); gene X; gene do "core"; gene polimerase e gene "pré-core". As principais mutações ocorrem nos genes de superfície e nos genes "pré-core/core", podendo também ser conhecidas como hepatite oculta, uma vez que os marcadores de infecção ativa (AgHBs) e replicação viral (AgHBe) podem estar negativos. Assim, deve-se suspeitar de mutação viral nos casos em que a sorologia para a hepatite B indica imunidade ou parada da replicação com o quadro clínico evoluindo mal, excluído outras causas de hepatites

Open archives and instruments of quality management as resources for disseminating scientific information in occupational health and safety

The objective of this study is to present the philosophy of open archives as an instrument for occupational health and safety (OHS) management. The survey method stands for the bibliography research, together with an interview session with the 23 OSH management professionals that enabled the further understanding about access level and the perception on scientific information by these professionals. Qualitative and quantitative questionnaire analysis showed the open archives initiative, through digital information repositories as an instrument for the occupational health and safety management, as well as need of developing policies on incentive to generation and sharing of intellectual capital among the community in question, encouraging the construction of an OSH digital repository, for maintaining most of all the worker's physical and mental integrity. Lack of available information in this area is still a barrier to the occupational knowledge management for promoting the safety and healthy work development in the organizations.O objetivo do estudo foi apresentar a utilização da filosofia de arquivos abertos, aliada aos instrumentos de gestão da qualidade, PDCA e 5S, como um dos pilares para a gestão da segurança e saúde no trabalho (SST). O método de pesquisa se constituiu no levantamento bibliográfico, juntamente com uma sessão de entrevistas com 23 profissionais ligados à gestão da SST, que permitiu o delineamento do grau de acesso e a percepção destes sobre a informação científica. A análise qualitativa e quantitativa dos questionários apontou a iniciativa de arquivos abertos, por meio da utilização de repositórios digitais de informações, como um instrumento de apoio à gestão da segurança e saúde no trabalho, bem como identificou a necessidade do desenvolvimento de políticas de incentivo à geração e compartilhamento do capital intelectual entre a comunidade em questão encorajando a construção de um repositório digital na área de SST, visando sobretudo à preservação da integridade física e mental do trabalhador. Constatou-se que a carência de informações disponíveis na área em questão ainda é uma barreira para a gestão do conhecimento organizacional, no sentido de promover o desenvolvimento do trabalho seguro e saudável nas organizações.Fundação Jorge Duprat Figueiredo de Segurança e Medicina do TrabalhoUniversidade Federal de São Paulo (UNIFESP) Departamento de Ciências Exatas e da TerraUNIFESP, Depto. de Ciências Exatas e da TerraSciEL

Utilizando a plataforma fazgame no ensino de língua inglesa: primeiras experiências

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014A literatura tem reportado grandes vantagens em se utilizar jogos no ensino de línguas. Neste trabalho, apresentamos os jogos educacionais produzidos por um grupo do Pibid de Letras-Inglês da UEL por meio da plataforma Faz Game bem como analisamos as potencialidades e limitações da plataforma para o ensino de Língua Inglesa. Os resultados apontam que entre os aspectos positivos estão a possibilidade de (a) desenvolver a escrita criativa em Língua Inglesa e propostas interdisciplinares; (b) a aprendizagem de conteúdo significativo que seja de interesse do aluno e (c) oferecer jogo educacional como suporte ao conteúdo estudado na disciplina de LI. Entre as limitações da plataforma, figuram o fato de (a) não haver trilha sonora, (b) possuir poucos cenários, personagens; e pouca jogabilidade (falta de interação e contextos de imersão), (c) não possibilitar o uso de termos essenciais para jogos de transformação social (como por exemplo, o termo gay

Ugi post-condensation copper-triggered oxidative cascade towards pyrazoles

International audiencePyrazolidinones were prepared in a two-step sequence starting from a-hydrazonocarboxylic acids. After a four-component Ugi coupling, the resulting hydrazone was engaged in a copper triggered [3 + 2] cycloaddition/aerobic oxidation cascade. © 2011 Santos et al; licensee Beilstein-Institut

Yesterday\u27s Tomorrows at the Dawn of ICIS: 30 Year Re-Visions from the 1st ICIS Doctoral Consortium

ICIS 2009 marks the 30th anniversary of the 1st ICIS Doctoral Consortium held in Philadelphia, Pennsylvania. There were 19 student participants at that doctoral consortium, and 9 faculty – all full of anticipation, excitement, and some apprehension: where would the IS field lead them? Or where could they lead it? What did the future hold? What were the visions of the future for the IS field? This panel re-examines yesterday’s tomorrow’s and re-visions what they had seen 30 years ago to see what we can learn today for the next 30 years for the future of the IS field and IS research. This panel seeks to give a sense of history and of past visions, while devoting a large part of the panel time and discussion to generating insights for the future of the IS field. The panel is co-chaired by three of the student participants of the 1st ICIS 1980 Doctoral Consortium (Ariav, Dos Santos, and El Sawy). The two key panelists/speakers, Peter G.W. Keen and Michael Ginzberg were at the 1st ICIS as plenary speakers and doctoral consortium faculty

Polyethylene Glycol-Stabilized Gold Nanostars-Loaded Microneedles for Photothermal Therapy of Melanoma

Gold nanostars (GNSs) as a photothermal agent have shown great potential for the treatment of cancers like melanoma. Irradiation of the photothermal agents with light of a suitable wavelength generates heat that induces cellular stress and protein denaturation in cancer cells. The delivery of GNSs to skin using fast dissolving microneedles (MNs) presents a promising approach for painless and convenient administration of the therapy. In this study, polyethylene glycol (PEG) stabilized GNSs able to absorb light in the near-infra red region and release heat (up to 65 °C, room temperature) are developed. The cytotoxicity of these nanoparticles is assessed before and after exposure to laser irradiation. GNSs show an instant lethal photothermal effect when tested on B16F10 melanoma cells upon irradiation with 808 nm at a power of 800 mW for 10 min. Loading the GNSs in polyvinylpyrrolidone (PVP) MNs preserves the photothermal effect of GNS and the mechanical properties of MNs. GNS-loaded PVP MNs show efficient piercing in excised porcine skin, fast dissolution in 3 min after insertion and elevation of the skin temperature after laser irradiation (808 nm, 800 mW, 10 min) to 63 °C. Consequently, PEG-stabilized GNSs and PVP MNs are a promising platform for photothermal therapy in melanoma treatment