Spacetime instability due to quantum gravity

We show that quantum gravity yields exponentially growing gravitational waves. Without a mechanism to stop these modes from growing, the universe would go through a gravitational collapse. For Minkowski background, we propose a solution by choosing an integration contour in Fourier space that does not enclose the problematic modes, thus preventing them from showing up in the effective theory. It turns out that this is only possible when the modes are removed altogether. For an expanding universe, we argue that the runaway modes can be managed accordingly to the dynamics of the Hubble constant, leading to important implications for astrophysics

GUP black hole remnants in quadratic gravity

The Hawking radiation of static, spherically symmetric, asymptotically flat solutions in quadratic gravity, is here explored. The emitted fermions are governed by the Dirac equation in the generalized uncertainty principle (GUP) context, that probes the spacetime (quantum) nature. The Hawking thermal spectrum is scrutinized out of the tunnelling method and the WKB procedure. The Hawking flux is shown to vanish for small black holes, for a precise combination of the GUP parameter and the coupling constants that drive the gravitational interaction in quadratic gravity, yielding absolutely stable black hole remnants.Comment: 18 pages, 5 figure

Transport coefficients in AdS/CFT and quantum gravity corrections due to a functional measure

The presence of a functional measure is scrutinized on both sides of the dual gauge/gravity correspondence. Corrections to the transport coefficients in relativistic hydrodynamics are obtained using the linear response procedure. In particular, using first-order hydrodynamics, the shear viscosity, entropy density, diffusion constant, and speed of sound are shown not to acquire any corrections from the functional measure of gravity, for a Minkowski background metric. On the other hand, the energy density, the pressure, the relaxation time, the bulk viscosity, the decay rate of sound waves, and coefficients of conformal traceless tensor fields, are shown to carry significant quantum corrections due to the functional measure, even for a flat background. They all acquire an imaginary part that reflects the instability of the strongly-coupled fluids on the boundary CFT. This opens up the possibility of testing quantum gravity with the quark-gluon plasma

Estudo das manifestações estomatológicas e erosão dental de pacientes com doenças gastrointestinais atendidos no serviço de gastroenterologia do HU/UFSC

TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências da Saúde. Odontologia.Algumas doenças gastrointestinais tais como Doença do Refluxo Gastroesofágico (DRGE), doenças inflamatórias intestinais e intolerância a certos alimentos, podem ter repercussões na cavidade oral. O objetivo desta pesquisa foi estudar a relação entre a presença de doenças do trato gastrointestinal com lesões na mucosa oral e erosão dental, bem como avaliar o fluxo e o pH salivares. Fizeram parte da amostra pacientes atendidos no Serviço de Gastroenterologia do Hospital Universitário da Universidade Federal de Santa Catarina. Após o consentimento dos pacientes, realizou-se a avaliação clínica da mucosa oral e das superfícies dentais presentes. O pH da saliva estimulada foi medido com o auxílio de um pHmetro. Os dados foram coletados ao longo de um ano. Dos 72 pacientes examinados, 55,6% apresentaram DRGE e 48,6% apresentaram doenças inflamatórias gastrointestinais; 75% relataram ter aftas frequentes e 28,6% dos pacientes com DRGE apresentavam algum grau de Erosão Dental; 37,5% apresentaram baixo fluxo salivar. Não foi possível estabelecer relação entre as doenças do trato gastrointestinal e a presença de lesões bucais e Erosão Dental provavelmente em função do reduzido número da amostra. Uma abordagem multidisciplinar entre os profissionais da saúde é fundamental no tratamento das doenças gastrointestinais e suas consequências, como é o caso da Erosão Dental.Some gastrointestinal diseases as Gastroesophageal Reflux Disease (GERD), inflammatory bowel diseases and food intolerances could cause oral consequences. The aim of this study was to evaluate the relationship between gastrointestinal diseases, and oral mucosal lesions and Dental Erosion. The sample was composed by 72 patients from Gastroenterology Ambulatory of the Hospital Universitário Professor Polydoro Ernani de São Thiago. After patient’s consent, they had their mouth and teeth examined trying to find oral lesions and enamel or dentin wear. It was also measured the pH stimulated saliva with a pHtester. Data were collected along a year. From 72 patients, 55,6% presented GERD and 48,6% inflammatory gastrointestinal diseases; 75% gave a history of recurrent aphthous stomatitis; 28,6% of GERD patients presented Dental Erosion; 37,5% had low saliva flow. It was not possible establish relationship between gastrointestinal diseases and the presence of oral lesions and Dental Erosion probably because the reduced number of the sample. A multidisciplinary team approach between health professionals is essential to providing the most effective treatment for gastrointestinal diseases and their consequences, like Dental Erosion

Fechamento de diastemas antero-superiores com resinas compostas: estudo de caso e revisão integrativa

Trabalho de Conclusão de Curso, apresentado para obtenção do grau de Cirurgião Dentista no curso de Odontologia da Universidade do Extremo Sul Catarinense – UNESCA existência de diastemas entre os dentes antero-superiores pode ocasionar desarmonia do sorriso e consequentemente prejudicar a estética do paciente. Com o aperfeiçoamento dos materiais e das técnicas restauradoras, o fechamento de diastemas utilizando resinas compostas, tornou-se uma alternativa viável, prática e econômica para solucionar a maior parte dos casos clínicos com presença de espaços interdentais. Este método de tratamento, permite restabelecer a função, proporcionando os contatos interproximais, melhorando desta maneira a estética do sorriso. Será realizado um trabalho de revisão integrativa associado a um estudo de caso clínico de fechamento de diastemas antero-superiores, empregando resinas compostas híbridas e nanoparticuladas, utilizando a técnica direta com guia palatino. O objetivo será mostrar que esta técnica de tratamento é confiável, tem boa durabilidade e é uma opção de baixo custo em relação à outros métodos

The secreted triose phosphate isomerase of Brugia malayi is required to sustain microfilaria production in vivo

Human lymphatic filariasis is a major tropical disease transmitted through mosquito vectors which take up microfilarial larvae from the blood of infected subjects. Microfilariae are produced by long-lived adult parasites, which also release a suite of excretory-secretory products that have recently been subject to in-depth proteomic analysis. Surprisingly, the most abundant secreted protein of adult Brugia malayi is triose phosphate isomerase (TPI), a glycolytic enzyme usually associated with the cytosol. We now show that while TPI is a prominent target of the antibody response to infection, there is little antibody-mediated inhibition of catalytic activity by polyclonal sera. We generated a panel of twenty-three anti-TPI monoclonal antibodies and found only two were able to block TPI enzymatic activity. Immunisation of jirds with B. malayi TPI, or mice with the homologous protein from the rodent filaria Litomosoides sigmodontis, failed to induce neutralising antibodies or protective immunity. In contrast, passive transfer of neutralising monoclonal antibody to mice prior to implantation with adult B. malayi resulted in 60–70% reductions in microfilarial levels in vivo and both oocyte and microfilarial production by individual adult females. The loss of fecundity was accompanied by reduced IFNγ expression by CD4+ T cells and a higher proportion of macrophages at the site of infection. Thus, enzymatically active TPI plays an important role in the transmission cycle of B. malayi filarial parasites and is identified as a potential target for immunological and pharmacological intervention against filarial infections

Imbibition in Disordered Media

The physics of liquids in porous media gives rise to many interesting phenomena, including imbibition where a viscous fluid displaces a less viscous one. Here we discuss the theoretical and experimental progress made in recent years in this field. The emphasis is on an interfacial description, akin to the focus of a statistical physics approach. Coarse-grained equations of motion have been recently presented in the literature. These contain terms that take into account the pertinent features of imbibition: non-locality and the quenched noise that arises from the random environment, fluctuations of the fluid flow and capillary forces. The theoretical progress has highlighted the presence of intrinsic length-scales that invalidate scale invariance often assumed to be present in kinetic roughening processes such as that of a two-phase boundary in liquid penetration. Another important fact is that the macroscopic fluid flow, the kinetic roughening properties, and the effective noise in the problem are all coupled. Many possible deviations from simple scaling behaviour exist, and we outline the experimental evidence. Finally, prospects for further work, both theoretical and experimental, are discussed.Comment: Review article, to appear in Advances in Physics, 53 pages LaTe