Uniqueness and Non-uniqueness in the Einstein Constraints

The conformal thin sandwich (CTS) equations are a set of four of the Einstein equations, which generalize the Laplace-Poisson equation of Newton's theory. We examine numerically solutions of the CTS equations describing perturbed Minkowski space, and find only one solution. However, we find {\em two} distinct solutions, one even containing a black hole, when the lapse is determined by a fifth elliptic equation through specification of the mean curvature. While the relationship of the two systems and their solutions is a fundamental property of general relativity, this fairly simple example of an elliptic system with non-unique solutions is also of broader interest.Comment: 4 pages, 4 figures; abstract and introduction rewritte

Strategies towards sustainability environmental from the local areas and the university

El propósito del presente trabajo es explorar un posible arreglo socioambiental pensado desde lo local que propicie el desarrollo sustentable, por medio del privilegio de la articulación de lo social (ciudadanía y educación) con el medio ambiente (capacidad de renovación). El planteamiento central es que ante un modelo social dominante que es insustentable, en el sentido que refuerza la desigualdad socioeconómica y el deterioro ambiental; se demanda pensar y actuar en formas novedosas e integradoras de lo social con la natural y del presente con el futuro para hacer posible sentar bases para un desarrollo sustentable de largo plazo. Para tal fin, se formula un arreglo que articule lo social (ciudadanía y educación) con el medio ambiente (capacidad de renovación) desde ámbitos locales, por medio de estrategias de acción gestionadas socialmente.The aim of this paper is to explore and present a suitable socio-environmental proposal conducive to sustainable development considering the local aspects emphasizing on the joint between the social (citizenship and education) with the environmental (renewability). The rationale of the study is that having a dominant unsustainable social model that reinforces socioeconomic inequality and environmental degradation, a need of developing more integrative and innovative ways to cope with the social and the natural as well as the present and the future is required in order to lay the foundations for a more long-term sustainable development. To that end, a suitable arrangement is presented in order to articulate the social aspects (citizenship and education) to the environmental ones (renewability) from a local perspective, managed through social action strategies.Fil: González López, Sergio. Universidad Autónoma del Estado de México. Instituto de Estudios sobre la Universidad.Fil: Salvador Benítez, J. Loreto. Universidad Autónoma del Estado de México. Instituto de Estudios sobre la Universidad.Fil: Arand a Sánchez, José María. Universidad Autónoma del Estado de México. Instituto de Estudios sobre la Universidad

FGF Signaling Inhibition in ESCs Drives Rapid Genome-wide Demethylation to the Epigenetic Ground State of Pluripotency

SummaryGenome-wide erasure of DNA methylation takes place in primordial germ cells (PGCs) and early embryos and is linked with pluripotency. Inhibition of Erk1/2 and Gsk3β signaling in mouse embryonic stem cells (ESCs) by small-molecule inhibitors (called 2i) has recently been shown to induce hypomethylation. We show by whole-genome bisulphite sequencing that 2i induces rapid and genome-wide demethylation on a scale and pattern similar to that in migratory PGCs and early embryos. Major satellites, intracisternal A particles (IAPs), and imprinted genes remain relatively resistant to erasure. Demethylation involves oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), impaired maintenance of 5mC and 5hmC, and repression of the de novo methyltransferases (Dnmt3a and Dnmt3b) and Dnmt3L. We identify a Prdm14- and Nanog-binding cis-acting regulatory region in Dnmt3b that is highly responsive to signaling. These insights provide a framework for understanding how signaling pathways regulate reprogramming to an epigenetic ground state of pluripotency