Non-adiabatic Chaplygin gas

The split of a generalised Chaplygin gas with an equation of state p = -A/\rho^{\alpha} into an interacting mixture of pressureless matter and a dark-energy component with equation of state p_{\Lambda} = - \rho_{\Lambda} implies the existence of non-adiabatic pressure perturbations. We demonstrate that the square of the effective (non-adiabatic) sound speed c_s of the medium is proportional to the ratio of the perturbations of the dark energy to those of the dark matter. Since, as demonstrated explicitly for the particular case \alpha = -1/2, dark-energy perturbations are negligible compared with dark-matter perturbations on scales that are relevant for structure formation, we find |c_s^2| << 1. Consequently, there are no oscillations or instabilities which have plagued previous adiabatic Chaplygin-gas models.Comment: Version to appear in Physics Letters

Multidisciplinary support teams for inclusive education during emergency online teaching: experiences and practices on the pedagogical triangulations forum

The Pedagogical Triangulations – COVID19 school experiences: the journey was a multi- support iniciative that gave voice to several school actors during the experience of online emergency teaching or school at distance (referred to as E@Da) reflection. On May 26th 2020, members of three different EMAEI (Multidisciplinary Support Team for Inclusive Education) were invited to testify of the effort to maintain the inclusion and equity of all students, ensuring that none are left behind.info:eu-repo/semantics/publishedVersio

Decifrando o genoma.

Os genes, unidades biologicas que determinam as caracteristicas de um organismo, estao contidos em moleculas de DNA presentes no nucleo das celulas. Portanto, o estudo do DNA e de fundamental importancia para o entendimento de como as caracteristicas de um organismo sao formadas. Com o grande avanco alcancado pelas tecnicas de Biologia molecular nas ultimas decadas, hoje, somos capazes de isolar e sequenciar moleculas de DNA de maneira rotineira. A partir da otimizacao das tecnicas de sequenciamento, surgiram programas com o objetivo de sequenciar genomas inteiros. atualmente, estao depositados em bancos de dados mais de 3 milhoes de sequencias de DNA e, grande parte delas ainda nao tem sua funcao conhecida. O processo de caracterizacao da funcao genica envolve um volume muito maior de pesquisas e conhecimentos do que as etapas de isolamento e sequenciamento. A funcao de um gene pode ser desvendada por meio de tecnicas de genetica direta ou reversa. Descrevem-se algumas das metodologias usadas para a caracterizacao da funcao genica, bem como o potencial dos programas de sequenciamento de genomas

Qualidade da água na engorda de tambaqui em viveiros sem renovação da água.

bitstream/CPATC/19780/1/f_18_2007.pd