On Infinite Quon Statistics and "Ambiguous" Statistics

We critically examine a recent suggestion that "ambiguous" statistics is equivalent to infinite quon statistics and that it describes a dilute, nonrelativistics ideal gas of extremal black holes. We show that these two types of statistics are different and that the description of extremal black holes in terms of "ambiguous" statistics cannot be applied.Comment: Latex, 9 pages, no figures, to appear in Mod.Phys.Lett.

Sobre la aparente extinción ‘atlántica’ de la araña viuda negra y primer registro de la especie para Navarra y La Rioja (Araneae: Theridiidae: Latrodectus)

Se presentan los primeros registros de Latrodectus tredecimguttatus (Rossi, 1790) para la Comunidad Foral de Navarra y la Comunidad Autónoma de La Rioja y se comentan algunas inconsistencias en los datos disponibles sobre su distribución en Europa occidental

TeV Scale Implications of Non Commutative Space time in Laboratory Frame with Polarized Beams

We analyze $e^{+}e^{-}\rightarrow \gamma\gamma$, $e^{-}\gamma \rightarrow e^{-}\gamma$ and $\gamma\gamma \rightarrow e^{+}e^{-}$ processes within the Seiberg-Witten expanded noncommutative scenario using polarized beams. With unpolarized beams the leading order effects of non commutativity starts from second order in non commutative(NC) parameter i.e. $O(\Theta^2)$, while with polarized beams these corrections appear at first order ($O(\Theta)$) in cross section. The corrections in Compton case can probe the magnetic component($\vec{\Theta}_B$) while in Pair production and Pair annihilation probe the electric component($\vec{\Theta}_E$) of NC parameter. We include the effects of earth rotation in our analysis. This study is done by investigating the effects of non commutativity on different time averaged cross section observables. The results which also depends on the position of the collider, can provide clear and distinct signatures of the model testable at the International Linear Collider(ILC).Comment: 22 pages, 19 figures, new comments and references added, few typos corrected, Published in JHE

Spacetime Noncommutativity in Models with Warped Extradimensions

We construct consistent noncommutative (NC) deformations of the Randall-Sundrum spacetime that solve the NC Einstein equations with a non-trivial Poisson tensor depending on the fifth coordinate. In a class of these deformations where the Poisson tensor is exponentially localized on one of the branes (the NC-brane), we study the effects on bulk particles in terms of Lorentz-violating operators induced by NC-brane interactions. We sketch two models in which massive bulk particles mediate NC effects to an almost-commutative SM-brane, such that observables at high energy colliders are enhanced with respect to low energy and astrophysical observables.Comment: 15 pages, LaTeX, pdf figures included, to appear in JHE

Abundancia y diversidad de arañas (Araneae) en olivares del distrito de Beja (Portugal) en diferentes sistemas de cultivo.

Durante 2011 y 2012 se estudió la diversidad de arañas en el suelo y en las copas de ocho olivares, cuatro de manejo biológico (dos de regadio y dos de secano) y cuatro de manejo no-biológico (dos con baja densidad de árboles y dos con una densidad elevada). Se capturaron en total 5454 arañas, de las que 1611 corresponden a olivares biológicos de regadío, 1191 a olivares biológicos de secano, 1175 a olivares intensivos de baja densidad y 1477 a olivares intensivos de alta densidad. En la muestra están representadas 31 familias y 127 especies. Se analizan los resultados desde una perspectiva faunística, destacando la presencia de algunas especies, bien por ser novedades para la fauna ibérica, bien por serlo para el distrito de Beja (Portugal). En función del planteamiento metodológico, se analizan las diferencias que muestran entre sí los diferentes sistemas de cultivo. Este análisis se realiza a través de parámetros ecológicos como la abundancia de individuos y la riqueza de especies. Se destacan las diferencias entre la fauna que habita las copas y la que explota los recursos del suelo.The diversity of spiders was studied in 2011 and 2012 in the ground and in the canopy of eight olive groves, of which four are managed organically and four are managed non-organically. In total, 5454 spiders were captured, 1611 in irrigated organic groves, 1191 in non-irrigated organic groves, 1175 in intensive groves with low density, and 1477 in intensive groves with high density. The captured individuals encompassed 31 families and 127 species. The results were analysed from a faunistic perspective, with emphasis on the presence of some species because of their novelty for the Iberian fauna, or for the district of Beja (Portugal). According to the methodological approach, the differences between the different systems of management were studied through some ecological parameters, such as species abundance and species richness. The differences between the fauna inhabiting the soil and the canopy are also outlined.info:eu-repo/semantics/publishedVersio

Constraining noncommutative field theories with holography

An important window to quantum gravity phenomena in low energy noncommutative (NC) quantum field theories (QFTs) gets represented by a specific form of UV/IR mixing. Yet another important window to quantum gravity, a holography, manifests itself in effective QFTs as a distinct UV/IR connection. In matching these two principles, a useful relationship connecting the UV cutoff $\Lambda_{\rm UV}$, the IR cutoff $\Lambda_{\rm IR}$ and the scale of noncommutativity $\Lambda_{\rm NC}$, can be obtained. We show that an effective QFT endowed with both principles may not be capable to fit disparate experimental bounds simultaneously, like the muon $g-2$ and the masslessness of the photon. Also, the constraints from the muon $g-2$ preclude any possibility to observe the birefringence of the vacuum coming from objects at cosmological distances. On the other hand, in NC theories without the UV completion, where the perturbative aspect of the theory (obtained by truncating a power series in $\Lambda_{\rm NC}^{-2}$) becomes important, a heuristic estimate of the region where the perturbative expansion is well-defined $E/ \Lambda_{\rm NC} \lesssim 1$, gets affected when holography is applied by providing the energy of the system $E$ a $\Lambda_{\rm NC}$-dependent lower limit. This may affect models which try to infer the scale $\Lambda_{\rm NC}$ by using data from low-energy experiments.Comment: 4 pages, version to be published in JHE

Neutrino-electron scattering in noncommutative space

Neutral particles can couple with the $U(1)$ gauge field in the adjoint representation at the tree level if the space-time coordinates are noncommutative (NC). Considering neutrino-photon coupling in the NC QED framework, we obtain the differential cross section of neutrino-electron scattering. Similar to the magnetic moment effect, one of the NC terms is proportional to $\frac 1 T$, where $T$ is the electron recoil energy. Therefore, this scattering provides a chance to achieve a stringent bound on the NC scale in low energy by improving the sensitivity to the smaller electron recoil energy.Comment: 12 pages, 2 figure