Bouncing Loop Quantum Cosmology from F(T)F(T) gravity

The big bang singularity could be understood as a breakdown of Einstein's General Relativity at very high energies. Adopting this viewpoint, other theories, that implement Einstein Cosmology at high energies, might solve the problem of the primeval singularity. One of them is Loop Quantum Cosmology (LQC) with a small cosmological constant that models a universe moving along an ellipse, which prevents singularities like the big bang or the big rip, in the phase space $(H,\rho)$, where $H$ is the Hubble parameter and $\rho$ the energy density of the universe. Using LQC when one considers a model of universe filled by radiation and matter where, due to the cosmological constant, there are a de Sitter and an anti de Sitter solution. This means that one obtains a bouncing non-singular universe which is in the contracting phase at early times. After leaving this phase, i.e., after bouncing, it passes trough a radiation and matter dominated phase and finally at late times it expands in an accelerated way (current cosmic acceleration). This model does not suffer from the horizon and flatness problems as in big bang cosmology, where a period of inflation that increases the size of our universe in more than 60 e-folds is needed in order to solve both problems. The model has two mechanisms to avoid these problems: The evolution of the universe through a contracting phase and a period of super-inflation ($\dot{H}> 0$)

On R+αR2R+\alpha R^2 Loop Quantum Cosmology

Working in Einstein frame we introduce, in order to avoid singularities, holonomy corrections to the $f(R)=R+\alpha R^2$ model. We perform a detailed analytical and numerical study when holonomy corrections are taken into account in both Jordan and Einstein frames obtaining, in Jordan frame, a dynamics which differs qualitatively, at early times, from the one of the original model. More precisely, when holonomy corrections are taken into account the universe is not singular, starting at early times in the contracting phase and bouncing to enter in the expanding one where, as in the original model, it inflates. This dynamics is completely different from the one obtained in the original $R+\alpha R^2$ model, where the universe is singular at early times and never bounces. Moreover, we show that these holonomy corrections may lead to better predictions for the inflationary phase as compared with current observations.Comment: 22 pages, 5 figures. Version accepted for publication in Physical Review

A Parametrization for K+→π+π−e+νK^+\to \pi^+\pi^- e^+\nu

We discuss various models and Chiral Perturbation Theory results for the $K_{l4}$ form factors $F$ and $G$. We check in how much a simple parametrization with a few parameters can be used to extract information from experiment.Comment: 19 pages, 14 figure

Fastest non-ionic azo dyes and transfer of their thermal isomerisation kinetics into liquid-crystalline materials

Push-pull bithienylpyrrole-based azo dyes exhibit thermal isomerisation rates as fast as 1.4 μs in acetonitrile at 298 K becoming, thus, the fastest neutral azo dyes reported so far. These remarkably low relaxation times can be transferred into liquid-crystalline matrixes enabling light-triggered oscillations in the optical density of the final material up to 11 kHz under ambient conditions.Financial support for this research was obtained from the Ministerio de Economía y Competitividad (Spain, CTQ2012-36074 and CTQ2015-65770-P). The authors thank Prof. Santi Nonell for his help with the flash photolysis measurements. Thanks are also due to: Fundação para a Ciência e Tecnologia (FCT) for a PhD grant to M. C. R. Castro (SFRH/BD/78037/2011); FEDERCOMPETE for financial support through the Centro de Quı ´mica – UM, PEst-C/QUI/UI0686/2013 (FCOMP-01-0124-FEDER-037302). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT

Characterization of activated carbon fiber/polyaniline materials by position-resolved microbeam small-angle X-ray scattering

Activated carbon fiber (ACF)/polyaniline (PANI) materials have been prepared using two different methods, viz. chemical and electrochemical polymerization. Electrochemical characterization of both materials shows that the electrodes with polyaniline have a higher capacitance than does a pristine porous carbon electrode. To analyze the distribution of PANI within the ACF, characterization by position-resolved microbeam small-angle X-ray scattering (μSAXS) has been carried out. μSAXS results obtained with a single ACF indicate that, for the experimental conditions used, a PANI coating is formed inside the micropores and that it is higher in the external regions of the ACF than in the core. Additionally, it seems that the penetration of PANI inside the fibers occurs in a larger extent for the chemical polymerization or, in other words, for the electrochemically polymerized sample there is a slightly larger accumulation of PANI in the external regions of the ACF.Fil: Salinas-Torres, D.. Universida de Alicante; EspañaFil: Sieben, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Lozano-Castelló, D.. Universida de Alicante; EspañaFil: Morallón, E.. Universida de Alicante; EspañaFil: Burghammer, M.. EuropeanSynchrotronRadiationFacility; FranciaFil: Riekel, C.. EuropeanSynchrotronRadiationFacility; FranciaFil: Cazorla Amorós, Diego. Universida de Alicante; Españ

Early deviations in performance, metabolic and immunological indicators affect stayability in rabbit females

[EN] The main purpose of this study was to find several early factors affecting stayability in rabbit females. To reach this goal, 203 females were used from their first artificial insemination to their sixth parturition. Throughout that period, 48 traits were recorded, considered to be performance, metabolic and immunological indicators. These traits were initially recorded in females' first reproductive cycle. Later, removed females due to death or culling and those that were non-removed were identified. A first analysis was used to explore whether it was possible to classify females between those reaching and those not reaching up to the mean lifespan of a rabbit female (the fifth reproductive) cycle using information from the first reproductive cycle. The analysis results showed that 97% of the non-removed females were classified correctly, whereas only 60% of the removed females were classified as animals to be removed. The reason for this difference lies in the model's characteristics, which was designed using early traits and was able to classify only the cases in which females would be removed due to performance, metabolic or immunologic imbalances in their early lives. Our results suggest that the model defines the necessary conditions, but not the sufficient ones, for females to remain alive in the herd. The aim of a second analysis was to find out the main early differences between the non-removed and removed females. The live weights records taken in the first cycle indicated that the females removed in their first cycle were lighter, while those removed in their second cycle were heavier with longer stayability (-203 and +202 g on average, respectively; P < 0.05). Non-removed females showed higher glucose and lower beta-hydroxybutyrate concentrations in the first cycle than the removed females (+4.8 and -10.7%, respectively; P < 0.05). The average lymphocytes B counts in the first cycle were 22.7% higher in the non-removed females group (P < 0.05). The females removed in the first reproductive cycle presented a higher granulocytes/lymphocytes ratio in this cycle than those that at least reached the second cycle (4.81 v. 1.66; P < 0.001). Consequently, non-removed females at sixth parturition offered adequate body development and energy levels, less immunological stress and a more mature immune function in the first reproductive cycle. The females that deviated from this pattern were at higher risk of being removed from the herd.This study was supported by the Interministerial Commission for Science and Technology (CICYT) of the Spanish Government (AGL2014-53405-C2-1-P, AGL2014-53405C2-2-P and AGL2017-85162-C2-1-R). The grants awarded to Mariola Penades and Alberto Arnau from the Spanish Ministry of Education, Culture and Sport (AP2010-3907 and BES-2012-052345, respectively) are also gratefully acknowledged.Penadés, M.; Arnau-Bonachera, A.; Selva, L.; Viana, D.; Larsen, T.; Corpa, JM.; Pascual Amorós, JJ.... (2020). Early deviations in performance, metabolic and immunological indicators affect stayability in rabbit females. Animal. 14(4):780-789. https://doi.org/10.1017/S1751731119002489S780789144Baselga M 2004. Genetic improvement of meat rabbits. Programmes and diffusion. In Proceedings of the 8th World Rabbit Congress, 7–10 September 2004, Puebla, Mexico, pp. 1–13.Bauman, D. E., & Bruce Currie, W. (1980). Partitioning of Nutrients During Pregnancy and Lactation: A Review of Mechanisms Involving Homeostasis and Homeorhesis. Journal of Dairy Science, 63(9), 1514-1529. doi:10.3168/jds.s0022-0302(80)83111-0Davis, A. K., Maney, D. L., & Maerz, J. C. (2008). The use of leukocyte profiles to measure stress in vertebrates: a review for ecologists. Functional Ecology, 22(5), 760-772. doi:10.1111/j.1365-2435.2008.01467.xDavis, W. C., & Hamilton, M. J. (2008). Use of flow cytometry to develop and characterize a set of monoclonal antibodies specific for rabbit leukocyte differentiation molecules. Journal of Veterinary Science, 9(1), 51. doi:10.4142/jvs.2008.9.1.51Dufort F 2012. Contribution of glucose metabolism to the B lymphocyte responses. PhD thesis, Boston College, Boston, MA, USA.Friggens, N. C., Brun-Lafleur, L., Faverdin, P., Sauvant, D., & Martin, O. (2013). Advances in predicting nutrient partitioning in the dairy cow: recognizing the central role of genotype and its expression through time. Animal, 7, 89-101. doi:10.1017/s1751731111001820García-Quirós, A., Arnau-Bonachera, A., Penadés, M., Cervera, C., Martínez-Paredes, E., Ródenas, L., … Pascual, J. J. (2014). A robust rabbit line increases leucocyte counts at weaning and reduces mortality by digestive disorder during fattening. Veterinary Immunology and Immunopathology, 161(3-4), 123-131. doi:10.1016/j.vetimm.2014.07.005Gross, W. B., & Siegel, H. S. (1983). Evaluation of the Heterophil/Lymphocyte Ratio as a Measure of Stress in Chickens. Avian Diseases, 27(4), 972. doi:10.2307/1590198Guerrero, I., Ferrian, S., Blas, E., Pascual, J. J., Cano, J. L., & Corpa, J. M. (2011). Evolution of the peripheral blood lymphocyte populations in multiparous rabbit does with two reproductive management rhythms. Veterinary Immunology and Immunopathology, 140(1-2), 75-81. doi:10.1016/j.vetimm.2010.11.017Harano, Y., Ohtsuki, M., Ida, M., Kojima, H., Harada, M., Okanishi, T., … Shigeta, Y. (1985). Direct automated assay method for serum or urine levels of ketone bodies. Clinica Chimica Acta, 151(2), 177-183. doi:10.1016/0009-8981(85)90321-3Jacobsen, C. N., Aasted, B., Broe, M. K., & Petersen, J. L. (1993). Reactivities of 20 anti-human monoclonal antibodies with leucocytes from ten different animal species. Veterinary Immunology and Immunopathology, 39(4), 461-466. doi:10.1016/0165-2427(93)90075-fJasper, P. J., Zhai, S.-K., Kalis, S. L., Kingzette, M., & Knight, K. L. (2003). B Lymphocyte Development in Rabbit: Progenitor B Cells and Waning of B Lymphopoiesis. The Journal of Immunology, 171(12), 6372-6380. doi:10.4049/jimmunol.171.12.6372Jeklova, E., Leva, L., & Faldyna, M. (2007). Lymphoid organ development in rabbits: Major lymphocyte subsets. Developmental & Comparative Immunology, 31(6), 632-644. doi:10.1016/j.dci.2006.10.002Jeklova, E., Leva, L., Knotigova, P., & Faldyna, M. (2009). Age-related changes in selected haematology parameters in rabbits. Research in Veterinary Science, 86(3), 525-528. doi:10.1016/j.rvsc.2008.10.007Jeklova, E., Leva, L., Kudlackova, H., & Faldyna, M. (2007). Functional development of immune response in rabbits. Veterinary Immunology and Immunopathology, 118(3-4), 221-228. doi:10.1016/j.vetimm.2007.05.003Kotani, M., Yamamura, Y., Tamatani, T., Kitamura, F., & Miyasaka, M. (1993). Generation and characterization of monoclomal antibodies against rabbit CD4, CD5 and CD11a antigens. Journal of Immunological Methods, 157(1-2), 241-252. doi:10.1016/0022-1759(93)90093-mKotani, M., Yamamura, Y., Tsudo, M., Tamatani, T., Kitamura, F., & Miyasaka, M. (1993). Generation of Monoclonal Antibodies to the Rabbit Interleukin-2 ReceptoraChain (CD25) and Its Distribution in HTLV-1-transformed Rabbit T Cells. Japanese Journal of Cancer Research, 84(7), 770-775. doi:10.1111/j.1349-7006.1993.tb02042.xMartin, O., & Sauvant, D. (2010). A teleonomic model describing performance (body, milk and intake) during growth and over repeated reproductive cycles throughout the lifespan of dairy cattle. 2. Voluntary intake and energy partitioning. 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Thermal rho and sigma mesons from chiral symmetry and unitarity

We study the temperature evolution of the rho and sigma mass and width, using a unitary chiral approach. The one-loop pion-pion scattering amplitude in Chiral Perturbation Theory at finite temperature is unitarized via the Inverse Amplitude Method. Our results predict a clear increase with T of both the rho and sigma widths. The masses decrease slightly for high T, while the rho-pion-pion coupling increases. The rho behavior seems to be favored by experimental results. In the sigma case, it signals chiral symmetry restoration.Comment: 5 pages, 5 figures, revtex. References and brief comments added. Final version to appear in Phys. Rev.

Magnetic zeolites: novel nanoreactors through radiofrequency heating

Many catalytic applications use conventional heating to increase the temperature to allow the desired reaction. A novel methodology is presented for the preparation of magnetic zeolite-based catalysts, allowing more efficient radiofrequency heating. These nanoreactors are tested in the isomerisation of citronellal with successful results and without any apparent deactivation

Meson-meson scattering within one loop Chiral Perturbation Theory and its unitarization

We present the complete one-loop calculation of all the two meson scattering amplitudes within the framework of SU(3) Chiral Perturbation Theory, which includes pions, kaons and the eta. In addition, we have unitarized these amplitudes with the coupled channel Inverse Amplitude Method, which ensures simultaneously the good low energy properties of Chiral Perturbation Theory and unitarity. We show how this method provides a remarkable description of meson-meson scattering data up to 1.2 GeV including the scattering lengths and the generation of seven light resonances, which is consistent with previous determination of the chiral parameters. Particular attention is paid to discuss the differences and similarities of this work with previous analysis in the literature.Comment: 20 pages, 5 figures. Comments on sigma, kappa and eta', as well as some references added. Final version to appear in Phys.Rev.