Bubble universes and traversable wormholes

Bubble universes and traversable wormholes in general relativity can be realized as two sides of the same concept. To exemplify it, we find, display, and study in a unified manner a Minkowski-Minkowski closed universe and a Minkowski-Minkowski traversable wormhole. By joining two 3-dimensional flat balls along a thin shell two-sphere of matter, i.e., a spherical domain wall, into a single spacetime one gets a Minkowski-Minkowski static closed universe, i.e., a bubble universe. By joining two 3-dimensional complements of flat balls along a thin shell two-sphere of matter, i.e., a spherical throat, into a single spacetime one gets a Minkowski-Minkowski static open universe which is a traversable wormhole. Thus, Minkowski-Minkowski bubble universes and wormholes can be seen as complementary to each other. It is also striking that these two spacetimes, the Minkowski-Minkowski bubble universe and the Minkowski-Minkowski traversable wormhole, have resemblances with two well-known static universes of general relativity. The Minkowski-Minkowski static closed universe, i.e., the Minkowski-Minkowski bubble universe, resembles in many aspects the Einstein universe, i.e., a static closed spherical universe homogeneously filled with dust matter and with a cosmological constant. The Minkowski-Minkowski static open universe, i.e., the Minkowski-Minkowski traversable wormhole, resembles the Friedmann static universe, i.e., a static open hyperbolic universe homogeneously filled with negative energy density dust and with a negative cosmological, which is a universe with two disjoint branes, or branches, and can be considered a failed wormhole. In this light, the Einstein static closed universe and the Friedmann static open universe should also be seen as the two sides of the same concept, i.e., they are complementary to each other. The scheme is completed by performing a linear stability analysis for the Minkowski-Minkowski bubble universe and the Minkowski-Minkowski traversable wormhole and also by comparing it to the stability of the Einstein static universe and the Friedmann static universe, respectively. This complementarity between bubble universes and traversable wormholes, that exists for these instances of static spacetimes, can be carried out for dynamical spacetimes, indicating that such a complementarity is quite general. The overall study suggests that bubble universes and traversable wormholes can be seen as coming out of the same concept, and thus, if one type of solution exists the other should also exist.info:eu-repo/semantics/acceptedVersio

Relativistic cosmology and intrinsic spin of matter: Results and theorems in Einstein-Cartan theory

We start by presenting the general set of structure equations for the 1+3 threading spacetime decomposition in four spacetime dimensions, valid for any theory of gravitation based on a metric compatible affine connection. We then apply these equations to the study of cosmological solutions of the Einstein-Cartan theory in which the matter is modeled by a perfect fluid with intrinsic spin. It is shown that the metric tensor can be described by a generic Friedman-Lemaître-Robertson-Walker solution. However, due to the presence of torsion the Weyl tensors might not vanish. The coupling between the torsion and Weyl tensors leads to the conclusion that, in this cosmological model, the universe must either be flat or open, excluding definitely the possibility of a closed universe. In the open case, we derive a wave equation for the traceless part of the magnetic part of the Weyl tensor and show how the intrinsic spin of matter in a dynamic universe leads to the generation and emission of gravitational waves. Last, in this cosmological model, it is found that the torsion tensor, which has an intrinsic spin as its source, contributes to a positive accelerated expansion of the universe. Comparing the theoretical predictions of the model with the current experimental data, we conclude that torsion cannot completely replace the role of a cosmological constant.info:eu-repo/semantics/acceptedVersio

Axon diversity of lamina I local-circuit neurons in the lumbar spinal cord

Spinal lamina I is a key area for relaying and integrating information from nociceptive primary afferents with various other sources of inputs. Although lamina I projection neurons have been intensively studied, much less attention has been given to local-circuit neurons (LCNs), which form the majority of the lamina I neuronal population. In this work the infrared light-emitting diode oblique illumination technique was used to visualize and label LCNs, allowing reconstruction and analysis of their dendritic and extensive axonal trees. We show that the majority of lamina I neurons with locally branching axons fall into the multipolar (with ventrally protruding dendrites) and flattened (dendrites limited to lamina I) somatodendritic categories. Analysis of their axons revealed that the initial myelinated part gives rise to several unmyelinated small-diameter branches that have a high number of densely packed, large varicosities and an extensive rostrocaudal (two or three segments), mediolateral, and dorsoventral (reaching laminae III–IV) distribution. The extent of the axon and the occasional presence of long, solitary branches suggest that LCNs may also form short and long propriospinal connections. We also found that the distribution of axon varicosities and terminal field locations show substantial heterogeneity and that a substantial portion of LCNs is inhibitory. Our observations indicate that LCNs of lamina I form intersegmental as well as interlaminar connections and may govern large numbers of neurons, providing anatomical substrate for rostrocaudal “processing units” in the dorsal horn

PRICE RELATIONSHIPS FOR MEXICAN FRESH TOMATOES IN U.S. AND MEXICAN TERMINAL MARKETS

Tomato trade between the U.S. and Mexico has grown significantly during the past decade, with significant implications for markets in both countries. This work examines how terminal market prices for Mexican fresh tomatoes are being affected by price dynamics in distant, integrated markets by analyzing reaction patterns to various innovation shocks. We conclude that a high interdependence in the price formation process between Mexican markets and Los Angeles, as well as among Mexican markets, exists.Crop Production/Industries, Demand and Price Analysis,

Human case of West Nile neuroinvasive disease in Portugal, summer 2015

A case of West Nile virus (WNV) infection was reported in the Algarve region, Portugal, in the first week of September 2015. WNV is known to circulate in Portugal, with occasional reports in horses and birds (2004 to 2011) and very sporadically human cases (in 2004 and in 2010). Here we present the clinical and laboratory aspects related to the first human case of West Nile neuroinvasive disease reported in Portugal