Conjectura de Goldbach
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1. The document describes a known solution to Einstein's field equations that represents the formation of non-spherical black holes through the collapse of pure electromagnetic monochromatic radiation.
2. The solution describes a metric with electromagnetic radiation modeled as a null electromagnetic field. The radiation can be linearly, circularly, or elliptically polarized depending on the choice of functions.
3. The metric can describe the formation of black holes in anti-de Sitter space, the destruction of naked singularities, or the evaporation of white holes through the ingoing or outgoing flow of electromagnetic radiation.
Silencing of the lncRNA Zeb2-NAT facilitates reprogramming of aged fibroblast...
Aging imposes a barrier to somatic cell reprogramming through poorly understood mechanisms. Here, we report that fibroblasts from old mice express higher levels of Zeb2, a transcription factor that activates epithelial-to-mesenchymal transition. Synthesis of Zeb2 protein is controlled by a natural antisense transcript named Zeb2-NAT. We show that transfection of adult fibroblasts with specific LNA Gapmers induces a robust downregulation of Zeb2-NAT transcripts and Zeb2 protein and enhances the reprogramming of old fibroblasts into pluripotent cells. We further demonstrate that Zeb2-NAT expression is precociously activated by differentiation stimuli in embryonic stem (ES) cells. By knocking down Zeb2-NAT, we were able to maintain ES cells challenged with commitment signals in the ground state of pluripotency. In conclusion, our study identifies a long noncoding RNA that is overlapping and antisense to the Zeb2 locus as a target for rejuvenation strategies.
Relatividade geral
1. O documento discute os fundamentos da Teoria da Relatividade Geral de Einstein. A teoria expande o postulado da relatividade para incluir sistemas em movimento não uniforme e gravidade.
2. A mecânica newtoniana não pode explicar satisfatoriamente porque corpos se comportam diferentemente em sistemas em rotação. A teoria da relatividade geral busca explicar tal comportamento através da influência de campos gravitacionais.
3. A teoria requer que as leis da física sejam válidas em qualquer sistema de refer
Anarquismo
Este trabalho discute teoricamente o anarquismo a partir de uma ampla gama de autores e episódios. Identifica problemas nos principais estudos sobre o tema relacionados a sua abordagem metodológica, definição de anarquismo e conclusões. Defende uma abordagem baseada em método histórico, grande volume de dados e noções de totalidade e interdependência para solucionar tais problemas e investigar adequadamente o anarquismo.
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