Axisymmetric Stationary Solutions as Harmonic Maps

We present a method for generating exact solutions of Einstein equations in vacuum using harmonic maps, when the spacetime possesses two commutating Killing vectors. This method consists in writing the axisymmetric stationry Einstein equations in vacuum as a harmonic map which belongs to the group SL(2,R), and decomposing it in its harmonic "submaps". This method provides a natural classification of the solutions in classes (Weil's class, Lewis' class etc).Comment: 17 TeX pages, one table,( CINVESTAV- preprint 12/93

On the Space Time of a Galaxy

We present an exact solution of the averaged Einstein's field equations in the presence of two real scalar fields and a component of dust with spherical symmetry. We suggest that the space-time found provides the characteristics required by a galactic model that could explain the supermassive central object and the dark matter halo at once, since one of the fields constitutes a central oscillaton surrounded by the dust and the other scalar field distributes far from the coordinate center and can be interpreted as a halo. We show the behavior of the rotation curves all along the background. Thus, the solution could be a first approximation of a ``long exposition photograph'' of a galaxy.Comment: 8 pages REVTeX, 11 eps figure

Oscillatons revisited

In this paper, we study some interesting properties of a spherically symmetric oscillating soliton star made of a real time-dependent scalar field which is called an oscillaton. The known final configuration of an oscillaton consists of a stationary stage in which the scalar field and the metric coefficients oscillate in time if the scalar potential is quadratic. The differential equations that arise in the simplest approximation, that of coherent scalar oscillations, are presented for a quadratic scalar potential. This allows us to take a closer look at the interesting properties of these oscillating objects. The leading terms of the solutions considering a quartic and a cosh scalar potentials are worked in the so called stationary limit procedure. This procedure reveals the form in which oscillatons and boson stars may be related and useful information about oscillatons is obtained from the known results of boson stars. Oscillatons could compete with boson stars as interesting astrophysical objects, since they would be predicted by scalar field dark matter models.Comment: 10 pages REVTeX, 10 eps figures. Updated files to match version published in Classical and Quantum Gravit

Quintessence and Scalar Dark Matter in the Universe

Continuing with previous works, we present a cosmological model in which dark matter and dark energy are modeled by scalar fields $\Phi$ and $\Psi$, respectively, endowed with the scalar potentials $V(\Phi)=V_{o}[ \cosh {(\lambda \sqrt{\kappa_{o}}\Phi)}-1]$ and $\tilde{V}(\Psi)=\tilde{V_{o}}[ \sinh {(\alpha \sqrt{\kappa_{o}}\Psi)}] ^{\beta}$. This model contains 95% of scalar field. We obtain that the scalar dark matter mass is $m_{\Phi}\sim 10^{-26}eV.$ The solution obtained allows us to recover the success of the standard CDM. The implications on the formation of structure are reviewed. We obtain that the minimal cutoff radio for this model is $r_{c}\sim 1.2 kpc.$Comment: 4 pages REVTeX, 3 eps color figures. Minor changes and references updated. To appear in Classical and Quantum Gravity as a Letter to the Editor. More information at http://www.fis.cinvestav.mx/~siddh/PHI

Decoherence, pointer engineering and quantum state protection

We present a proposal for protecting states against decoherence, based on the engineering of pointer states. We apply this procedure to the vibrational motion of a trapped ion, and show how to protect qubits, squeezed states, approximate phase eigenstates and superpositions of coherent states.Comment: 1 figur

Austerity, the state and common sense in Europe: A comparative perspective on Italy and Portugal

In this article, we examine the making of austerity as common sense, located at the intersection of state interventions and the everyday practices and moral logics through which austerity emerges as an acceptable livelihood possibility for individuals, households and communities. Our argument is based on the comparative analysis of austerity in Italy and Portugal, with a focus on popular austerities among working-class households in two post-industrial towns. With the aim of addressing the conundrum of the pervasiveness of austerity, we emphasize the relevance of Gramsci’s notion of common sense to expand the anthropological theorization of austerity as a hegemonic project combining coercion and consent, capable of reconfiguring the state, and as a field of contradictions endemic to the very making of common sense. We argue that austerity regimes become operative through the deployment of institutional coercive practices, moral arguments and the ideological co-optation of historical legacies of austerity embodied by ordinary people in their livelihood praxis.info:eu-repo/semantics/acceptedVersio

Produção de água de coco do híbrido Anão Vermelho do Brasil de Gramane x Gigante do oeste africano em função da idade de colheita do fruto.

bitstream/CPATC-2009-09/20636/1/cot_85.pdfMeta 2008

Banana: instruções práticas de cultivo.

Importância; Escolha e preparo do terreno; Adubação; Variedades e seleção do material; Espaçamento; Plantio; Tratos; Culturais; Pragas; Broca do rizoma; Tripes; Broca-rajada; Lagartas desfolhadoras; Ácaros de teia; Abelha arapuá; Doenças; Mal-do-Panamá; Sigatoka-amarela; Sigatoka-negra; Colheita.bitstream/CNPMF/23308/1/documento_161.pd

Galactic Collapse of Scalar Field Dark Matter

We present a scenario for galaxy formation based on the hypothesis of scalar field dark matter. We interpret galaxy formation through the collapse of a scalar field fluctuation. We find that a cosh potential for the self-interaction of the scalar field provides a reasonable scenario for galactic formation, which is in agreement with cosmological observations and phenomenological studies in galaxies.Comment: 4 pages, 3 figue