Spatial Periodicity of Galaxy Number Counts, CMB Anisotropy, and SNIa Hubble Diagram Based on the Universe Accompanied by a Non-Minimally Coupled Scalar Field

We have succeeded in establishing a cosmological model with a non-minimally coupled scalar field $\phi$ that can account not only for the spatial periodicity or the {\it picket-fence structure} exhibited by the galaxy $N$-$z$ relation of the 2dF survey but also for the spatial power spectrum of the cosmic microwave background radiation (CMB) temperature anisotropy observed by the WMAP satellite. The Hubble diagram of our model also compares well with the observation of Type Ia supernovae. The scalar field of our model universe starts from an extremely small value at around the nucleosynthesis epoch, remains in that state for sufficiently long periods, allowing sufficient time for the CMB temperature anisotropy to form, and then starts to grow in magnitude at the redshift $z$ of $\sim 1$, followed by a damping oscillation which is required to reproduce the observed picket-fence structure of the $N$-$z$ relation. To realize such behavior of the scalar field, we have found it necessary to introduce a new form of potential $V(\phi)\propto \phi^2\exp(-q\phi^2)$, with $q$ being a constant. Through this parameter $q$, we can control the epoch at which the scalar field starts growing.Comment: 19 pages, 18 figures, Accepted for publication in Astrophysics & Space Scienc

Classical and Quantum Strings in compactified pp-waves and Godel type Universes

We consider Neveu-Schwarz pp-waves with spacetime supersymmetry. Upon compactification of a spacelike direction, these backgrounds develop Closed Null Curves (CNCs) and Closed Timelike Curves (CTCs), and are U-dual to supersymmetric Godel type universes. We study classical and quantum strings in this background, with emphasis on the strings winding around the compact direction. We consider two types of strings: long strings stabilized by NS flux and rotating strings which are stabilized against collapse by angular momentum. Some of the latter strings wrap around CNCs and CTCs, and are thus a potential source of pathology. We analyze the partition function, and in particular discuss the effects of these string states. Although our results are not conclusive, the partition function seems to be dramatically altered due to the presence of CNCs and CTCs. We discuss some interpretations of our results, including a possible sign of unitary violation.Comment: 42 pages, LaTeX, 2 figure

Phantom Divide Crossing with General Non-minimal Kinetic Coupling

We propose a model of dark energy consists of a single scalar field with a general non-minimal kinetic couplings to itself and to the curvature. We study the cosmological dynamics of the equation of state in this setup. The coupling terms have the form $\xi_{1} R f(\phi)\partial_{\mu}\phi\partial^{\mu}\phi$ and $\xi_{2} R_{\mu\nu}f(\phi)\partial^{\mu}\phi\partial^{\nu}\phi$ where $\xi_{1}$ and $\xi_{2}$ are coupling parameters and their dimensions depend on the type of function $f(\phi)$. We obtain the conditions required for phantom divide crossing and show numerically that a cosmological model with general non-minimal derivative coupling to the scalar and Ricci curvatures can realize such a crossing.Comment: 12 pages, 4 figures. Accepted for publication in Gen. Rel. Grav. arXiv admin note: substantial text overlap with arXiv:1105.4967, arXiv:1201.1627, and with arXiv:astro-ph/0610092 by other author

Anatomopathological findings of Testudines necropsied in the Distrito Federal, Brazil

ABSTRACT: In order to determine the main anatomopathological findings of Testudines necropsied in the Distrito Federal, all necropsy records performed at the “Laboratório de Patologia Veterinária” of the “Universidade de Brasília” (LPV-UnB) on Testudines during the period from January 2008 to July 2020 were reviewed. The 72 cases reviewed were grouped and classified according to species, sex, origin, season of occurrence, and diagnosis. In 69.44% of the cases the species was informed in the necropsy protocols, which included Phrynops geoffroanus (38%), Trachemys dorbigni (36%), Chelonoidis carbonaria (14%), Chelonoidis denticulata (10%) and Podocnemis expansa (2%). In 30.55% of the cases this parameter was not informed and were classified only as Testudines. In 41.66% of the cases the sex was informed, being female 22.22%, male 19.44%, and 58.33% were not informed. Of these animals 79.16% were from environmental agencies and 20.84% from zoos and/or guardians. In 70.83% of the animals analyzed they were directly related to the autumn and winter seasons, with June being the most frequent month (29.17%). The conclusive diagnosis was possible in 68.05% of the cases. The category of disorders caused by injurious agents (48.97%) was the most prevalent, followed by inflammatory disorders (32.65%) and nutritional and metabolic disorders (28.57%). The main diagnoses were carapace and/or plastron fracture with 30.61%, hepatic steatosis (20.40%) and pneumonia (10.22%). Most cases of carapace or plastron fracture and hepatic steatosis occurred in animals from environmental agencies.</jats:p