256 research outputs found

    Ψ=We±Φ\rm \Psi= W e^{\pm \Phi} quantum cosmological solutions for Class A Bianchi Models

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    We find solutions for quantum Class A Bianchi models of the form Ψ=We±Φ\rm \Psi=W e^{\pm \Phi} generalizing the results obtained by Moncrief and Ryan in standard quantum cosmology. For the II and IX Bianchi models there are other solutions Φ~2\rm \tilde\Phi_2, Φ~9\rm \tilde\Phi_9 to the Hamilton-Jacobi equation for which Ψ\rm \Psi is necessarely zero, in contrast with solutions found in supersymmetric quantum cosmology.Comment: 15 pages, Late

    Generalized information entropies depending only on the probability distribution

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    Systems with a long-term stationary state that possess as a spatio-temporally fluctuation quantity β\beta can be described by a superposition of several statistics, a "super statistics". We consider first, the Gamma, log-normal and FF-distributions of β\beta. It is assumed that they depend only on plp_l, the probability associated with the microscopic configuration of the system. For each of the three β\beta-distributions we calculate the Boltzmann factors and show that they coincide for small variance of the fluctuations. For the Gamma distribution it is possible to calculate the entropy in a closed form, depending on plp_l, and to obtain then an equation relating plp_l with βEl\beta E_l. We also propose, as other examples, new entropies close related with the Kaniadakis and two possible Sharma-Mittal entropies. The entropies presented in this work do not depend on a constant parameter qq but on plp_l. For the plp_l-Gamma distribution and its corresponding Bpl(E)B_{p_l}(E) Boltzmann factor and the associated entropy, we show the validity of the saddle-point approximation. We also briefly discuss the generalization of one of the four Khinchin axioms to get this proposed entropy.Comment: 13 pages, 3 figure

    Behind taxonomic variability: The functional redundancy in the tick microbiome

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    The taxonomic composition and diversity of tick midgut microbiota have been extensively studied in different species of the genera Rhipicephalus, Ixodes, Amblyomma, Haemaphysalis, Hyalomma, Dermacentor, Argas and Ornithodoros, while the functional significance of bacterial diversity has been proportionally less explored. In this study, we used previously published 16S amplicon sequence data sets from three Ixodes scapularis cohorts, two of uninfected nymphs, and one of larvae experimentally infected with Borrelia burgdorferi, to test the functional redundancy of the tick microbiome. We predicted the metabolic profiling of each sample using the state-of-the-art metagenomics tool PICRUSt2. The results showed that the microbiomes of all I. scapularis samples share only 80 taxa (24.6%, total 324), while out of the 342 metabolic pathways predicted, 82.7%, were shared by all the ticks. Borrelia-infected larvae lack 15.4% of pathways found in the microbiome of uninfected nymphs. Taxa contribution analysis showed that the functional microbiome of uninfected ticks was highly redundant, with, in some cases, up to 198 bacterial taxa contributing to a single pathway. However, Borrelia-infected larvae had a smaller redundancy with 6.7% of pathways provided by more than 100 genera, while 15.7–19.2% of pathways were provided by more than 100 genera in the two cohorts of uninfected ticks. In addition, we compared the functional profiles of three microbial communities from each data set, identified through a network-based approach, and we observed functional similarity between them. Based on the functional redundancy and functional similarity of the microbiome of ticks in different developmental stages and infection status, we concluded that the tick gut microbiota is a self-regulating community of very diverse bacteria contributing to a defined set of metabolic pathways and functions with yet unexplored relevance for tick fitness and/or bacterial community stability. We propose a change of focus in which the tick microbiome must be analyzed in all dimensions, highlighting their functional traits, instead of the conventional taxonomic profiling

    Supersymmetric FRW model and the ground state of supergravity

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    In this work we construct the vacuum configuration of supergravity interacting with homogeneous complex scalar matter fields. The corresponding configuration is of the FRW model invariant under the n=2n=2 local conformal time supersymmetry, which is a subgroup of the four dimensional space-time supersymmetry. We show, that the potential of the scalar matter fields is a function of the K\"ahler potential and of the arbitrary parameter α\alpha. This parameter enumerates the vacuum states. The scalar matter potential induces the spontaneous breaking of supersymmetry in supergravity. On the quantum level our model is a specific supersymmetric quantum mechanics, which admits quantum states in supergravity, and the states with zero energy are described by the wave function of the FRW universe.Comment: 18 pages, Revtex, submitted to PR

    No Quantum Super-Minisuperspace with Λ0\Lambda \ne 0

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    We show that the quantum super-minisuperspace of N=1 supergravity with Λ0\Lambda \ne 0 has no non-trivial physical states for class A Bianchi models. Hence, in super quantum cosmology, the vanishing of Λ\Lambda is a condition for the existence of the universe. We argue that this result implies that in full supergravity with Λ\Lambda there are no non-trivial physical states with a finite number of fermionic fields. We use the Jacobson canonical formulation.Comment: 9 pages, LaTeX, CIEA-94-0

    Parasitoid and ant interactions of some Iberian butterflies (Insecta: Lepidoptera)

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    As a result of recent field studies in the Iberian Peninsula, interactions between 17 parasitoid taxa and 17 butterfly species, and 9 species of Lycaenidae and 15 species of Formicidae are detailed and discussed. Several of these, which are presented quantitatively, are otherwise unrecorded in the literature, while others confirm previous records. Attention is drawn to the need for the deposition of voucher material and both carefully and prolonged quantitative recording in order to understand and conserve these vulnerable aspects of biodiversit

    Dispersal of the monarch butterfly (Danaus plexippus) over southern Spain from its breeding grounds

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    Dispersión de la mariposa monarca (Danaus plexippus) en el sur de España desde las zonas de apareamiento Durante el período comprendido entre los años 2000 y 2016, se detectaron mariposas monarca en 127 lugares fuera de las zonas costeras donde se reproducen habitualmente en el sur de la península ibérica. Estos datos se obtuvieron en verano e invierno, coincidiendo con la máxima abundancia de individuos y la mayor proporción de sitios ocupados en sus zonas de reproducción cercanas al estrecho de Gibraltar. Los individuos que se dispersan no tienen ninguna posibilidad de establecer nuevas colonias en estos sitios porque las plantas en las que ponen los huevos no crecen en las localidades en las que fueron detectados. Sin embargo, estos movimientos de dispersión podrían ser la causa de la colonización de plantas alimentarias que crecen en otras zonas de la península ibérica y en otros países del Mediterráneo.From 2000–2016, monarch butterflies were detected at 127 locations away from their usual coastal breeding areas in the south of the Iberian peninsula. These findings were recorded in the summer–autumn period, coinciding with the highest abundance of individuals and the highest proportion of patches occupied in their reproduction areas near the Strait of Gibraltar. These dispersing individuals have no chance of successfully establishing new colonies at these sites because the food plants for egg laying do not grow in the localities where they were detected. However, these dispersive movements could be the source of their successful colonisation on food plants growing in other areas of the Iberian peninsula and in other Mediterranean countries.Dispersión de la mariposa monarca (Danaus plexippus) en el sur de España desde las zonas de apareamiento Durante el período comprendido entre los años 2000 y 2016, se detectaron mariposas monarca en 127 lugares fuera de las zonas costeras donde se reproducen habitualmente en el sur de la península ibérica. Estos datos se obtuvieron en verano e invierno, coincidiendo con la máxima abundancia de individuos y la mayor proporción de sitios ocupados en sus zonas de reproducción cercanas al estrecho de Gibraltar. Los individuos que se dispersan no tienen ninguna posibilidad de establecer nuevas colonias en estos sitios porque las plantas en las que ponen los huevos no crecen en las localidades en las que fueron detectados. Sin embargo, estos movimientos de dispersión podrían ser la causa de la colonización de plantas alimentarias que crecen en otras zonas de la península ibérica y en otros países del Mediterráneo

    Time and "angular" dependent backgrounds from stationary axisymmetric solutions

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    Backgrounds depending on time and on "angular" variable, namely polarized and unpolarized S1×S2S^1 \times S^2 Gowdy models, are generated as the sector inside the horizons of the manifold corresponding to axisymmetric solutions. As is known, an analytical continuation of ordinary DD-branes, iDiD-branes allows one to find SS-brane solutions. Simple models have been constructed by means of analytic continuation of the Schwarzchild and the Kerr metrics. The possibility of studying the ii-Gowdy models obtained here is outlined with an eye toward seeing if they could represent some kind of generalized SS-branes depending not only on time but also on an ``angular'' variable.Comment: 24 pages, 5 figures, corrected typos, references adde

    Quantum Cosmology for a Quadratic Theory of Gravity

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    For pure fourth order (LR2{\cal{L}} \propto R^2) quantum cosmology the Wheeler-DeWitt equation is solved exactly for the closed homogeneous and isotropic model. It is shown that by imposing as boundary condition that Ψ=0\Psi = 0 at the origin of the universe the wave functions behave as suggested by Vilenkin.Comment: 13 pages, latex,no figure
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