736 research outputs found

    Scalar field in the Bianchi I: Non commutative classical and Quantum Cosmology

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    Using the ADM formalism in the minisuperspace, we obtain the commutative and noncommutative exact classical solutions and exact wave function to the Wheeler-DeWitt equation with an arbitrary factor ordering, for the anisotropic Bianchi type I cosmological model, coupled to a scalar field, cosmological term and barotropic perfect fluid. We introduce noncommutative scale factors, considering that all minisuperspace variables qi\rm q^i do not commute, so the symplectic structure was modified. In the classical regime, it is shown that the anisotropic parameter β±nc\rm \beta_{\pm nc} and the field ϕ\phi, for some value in the λeff\lambda_{eff} cosmological term and noncommutative θ\theta parameter, present a dynamical isotropization up to a critical cosmic time tct_{c}; after this time, the effects of isotropization in the noncommutative minisuperspace seems to disappear. In the quantum regimen, the probability density presents a new structure that corresponds to the value of the noncommutativity parameter.Comment: 17 pages, 6 figures, Acepted in IJT

    SMOS soil moisture product validation in croplands

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    A validation campaign has been carried out to evaluate the Level 2 Soil Moisture (SM) product (version 5.51) given by the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite in the Pampean Region of Argentina. The study region was selected because it is a plain, avoiding topography problems, with an SMOS nominal land use class (low vegetation crops, 1-2m height). Transects of ground SM measurements were collected at 5-cm and 6-cm depth using Delta-T ThetaProbe ML2x and Stevens Hydra Probe II SM sensors, respectively. The volumetric measurements were calibrated using gravimetric and bulk density data collected at the same time as the SM sensor measurements. The SM transects covered ISEA-grid SMOS nodes over four extensive agricultural areas with prevalence of soy crops (site 1: -32.982N, -62.505E; site 2: -32.510N, -62.788E; site 3: -32.024N, -63.692E; and site 4: -37.315N, -58.868E, WGS84). The validation sites were selected taking as reference the locations of permanent SM stations property of the Argentinean Comisión Nacional de Actividades Espaciales (CONAE, National Commission of Space Activities), Instituto Nacional de Tecnología Agropecuaria (INTA, National Institute of Farming Technology) and Instituto de Hidrología de Llanuras (IHLLA, Plain Hydrology Institute). Therefore, additionally to validate the SMOS SM product with the ground data collected during the experimental campaign, the measurements are useful to evaluate the station SM data reliability at the SMOS spatial resolution with the aim of using station data series as reference to test different versions of the SMOS SM product. Previously to the campaign, SMOS SM data variability, ESA Globcover land use classification, soil edaphic properties, water bodies and topography were analyzed around the station locations to select the best sites and the experimental methodology. Temperature vegetation dryness index (TVDI) temporal and spatial variability was also studied at the sites. Additionally, transects of land surface temperature were carried out with Cimel Electronique CE312 6-band radiometers concurrently with thermal-infrared (TIR) satellite overpasses. In previous works, we studied the dependence of land surface emissivities on SM. The analysis of concurrent TIR and SM data make possible to evaluate the utility of the SMOS SM product to improve land surface emissivities and temperature determinations from satellite, giving an added value to the research

    Modes, mechanisms and evidence of bet hedging in rotifer diapause traits

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    In this contribution, we review our knowledge on bet-hedging strategies associated with rotifer diapause. First, we describe the ecological scenario under which bet hedging is likely to have evolved in three diapause-related traits in monogonont rotifer populations: (1) the timing of sex (because diapausing eggs are produced via sexual reproduction), (2) the sexual reproduction ratio (i.e. the fraction of sexually reproducing females) and (3) the timing of diapausing egg hatching. Then, we describe how to discriminate among bet-hedging modes and discuss which modes and mechanisms better fit the variability observed in these traits in rotifers. Finally, we evaluate the strength of the empirical evidence for bet hedging in the scarce studies available, and we call for the need of research at different levels of biological complexity to fully understand bet hedging in rotifer diapause

    Different resource allocation strategies result from selection for litter size at weaning in rabbit does

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    This study examined the effect of long-term selection of a maternal rabbit line, solely for a reproductive criterion, on the ability of female rabbits to deal with constrained environmental conditions. Female rabbits from generations 16 and 36 (n = 72 and 79, respectively) of a line founded and selected to increase litter size at weaning were compared simultaneously. Female rabbits were subjected to normal (NC), nutritional (NF) or heat (HC) challenging conditions from 1st to 3rd parturition. Animals in NC and NF were housed at normal room temperatures (18°C to 25°C) and respectively fed with control (11.6 MJ digestible energy (DE)/kg dry matter (DM), 126 g digestible protein (DP)/kg DM, and 168 g of ADF/kg DM) or low-energy fibrous diets (9.1 MJ DE/kg DM, 104 g DP/kg DM and 266 g ADF/kg DM), whereas those housed in HC were subjected to high room temperatures (25°C to 35°C) and the control diet. The litter size was lower for female rabbits housed in both NF and HC environments, but the extent and timing where this reduction took place differed between generations. In challenging conditions (NF and HC), the average reduction in the reproductive performance of female rabbits from generation 16, compared with NC, was &#8722;2.26 (P<0.05) and &#8722;0.51 kits born alive at 2nd and 3rd parturition, respectively. However, under these challenging conditions, the reproductive performance of female rabbits from generation 36 was less affected at 2nd parturition (&#8722;1.25 kits born alive), but showed a greater reduction at the 3rd parturition (&#8722;3.53 kits born alive; P<0.05) compared with NC. The results also showed differences between generations in digestible energy intake, milk yield and accretion, and use of body reserves throughout lactation in NC, HC and NF, which together indicate that there were different resource allocation strategies in the animals from the different generations. Selection to increase litter size at weaning led to increased reproductive robustness at the onset of an environmental constraint, but failure to sustain the reproductive liability when the challenge was maintained in the long term. This response could be directly related to the shortterm environmental fluctuations (less severe) that frequently occur in the environment where this line has been selected.The authors thank Professor Enrique Blas Ferrer for his valuable comments on the initial version of this document, Juan Carlos Moreno for his help in conducting the trial at the experimental farm, and the Ministry of Economy and Competitiveness (Project: AGL2011-30170-C02-01) for economic support.Savietto, D.; Cervera Fras, MC.; Ródenas Martínez, L.; Martínez Paredes, EM.; Baselga Izquierdo, M.; García Diego, FJ.; Larsen, T.... (2014). Different resource allocation strategies result from selection for litter size at weaning in rabbit does. Animal. 8(4):618-628. https://doi.org/10.1017/S1751731113002437S61862884García-Diego, F.-J., Pascual, J. J., & Marco, F. (2011). Technical Note: Design of a large variable temperature chamber for heat stress studies in rabbits. World Rabbit Science, 19(4). doi:10.4995/wrs.2011.938Ragab, M., & Baselga, M. (2011). A comparison of reproductive traits of four maternal lines of rabbits selected for litter size at weaning and founded on different criteria. Livestock Science, 136(2-3), 201-206. doi:10.1016/j.livsci.2010.09.009Friggens, N. C. (2003). Body lipid reserves and the reproductive cycle: towards a better understanding. Livestock Production Science, 83(2-3), 219-236. doi:10.1016/s0301-6226(03)00111-8Littell, R. C., Henry, P. R., & Ammerman, C. B. (1998). Statistical analysis of repeated measures data using SAS procedures. Journal of Animal Science, 76(4), 1216. doi:10.2527/1998.7641216xEstany, J., Baselga, M., Blasco, A., & Camacho, J. (1989). Mixed model methodology for the estimation of genetic response to selection in litter size of rabbits. Livestock Production Science, 21(1), 67-75. doi:10.1016/0301-6226(89)90021-3Fernández-Carmona, J., Alqedra, I., Cervera, C., Moya, J., & Pascual, J. J. (2003). Effect of lucerne-based diets on performance of reproductive rabbit does at two temperatures. Animal Science, 76(2), 283-295. doi:10.1017/s1357729800053534Fernández-Carmona, J., Cervera, C., Sabater, C., & Blas, E. (1995). Effect of diet composition on the production of rabbit breeding does housed in a traditional building and at 30°C. Animal Feed Science and Technology, 52(3-4), 289-297. doi:10.1016/0377-8401(94)00715-lHarano, 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)90321-3Dauncey, M. J. (1990). Thyroid hormones and thermogenesis. Proceedings of the Nutrition Society, 49(2), 203-215. doi:10.1079/pns19900024Savietto, D., Blas, E., Cervera, C., Baselga, M., Friggens, N. C., Larsen, T., & Pascual, J. J. (2012). Digestive efficiency in rabbit does according to environment and genetic type. World Rabbit Science, 20(3). doi:10.4995/wrs.2012.1152Falconer, D. S. (1990). Selection in different environments: effects on environmental sensitivity (reaction norm) and on mean performance. Genetical Research, 56(1), 57-70. doi:10.1017/s0016672300028883Vicente, J., & García-Ximénez, F. (1993). Effects of strain and embryo transfer model (embryos from one versus two donor does/recipient) on results of cryopreservation in rabbit. Reproduction Nutrition Development, 33(1), 5-13. doi:10.1051/rnd:19930101Quiniou, N., Renaudeau, D., Dubois, S., & Noblet, J. (2000). Influence of high ambient temperatures on food intake and feeding behaviour of multiparous lactating sows. Animal Science, 70(3), 471-479. doi:10.1017/s1357729800051821Theilgaard, P., Sánchez, J. P., Pascual, J. J., Friggens, N. C., & Baselga, M. (2006). Effect of body fatness and selection for prolificacy on survival of rabbit does assessed using a cryopreserved control population. Livestock Science, 103(1-2), 65-73. doi:10.1016/j.livsci.2006.01.007Brecchia, G., Bonanno, A., Galeati, G., Federici, C., Maranesi, M., Gobbetti, A., … Boiti, C. (2006). Hormonal and metabolic adaptation to fasting: Effects on the hypothalamic–pituitary–ovarian axis and reproductive performance of rabbit does. Domestic Animal Endocrinology, 31(2), 105-122. doi:10.1016/j.domaniend.2005.09.006Piles, M., Garreau, H., Rafel, O., Larzul, C., Ramon, J., & Ducrocq, V. (2006). Survival analysis in two lines of rabbits selected for reproductive traits1. Journal of Animal Science, 84(7), 1658-1665. doi:10.2527/jas.2005-678Sanchez, J. P., Baselga, M., & Ducrocq, V. (2006). Genetic and environmental correlations between longevity and litter size in rabbits. Journal of Animal Breeding and Genetics, 123(3), 180-185. doi:10.1111/j.1439-0388.2006.00590.xQuevedo, F., Cervera, C., Blas, E., Baselga, M., & Pascual, J. J. (2006). Long-term effect of selection for litter size and feeding programme on the performance of reproductive rabbit does 2. Lactation and growing period. Animal Science, 82(5), 751-762. doi:10.1079/asc200688Vicente, J. S., & García-Ximénez, F. (1996). Direct transfer of vitrified rabbit embryos. Theriogenology, 45(4), 811-815. doi:10.1016/0093-691x(96)00010-6Coureaud, G., Fortun-Lamothe, L., Langlois, D., & Schaal, B. (2007). The reactivity of neonatal rabbits to the mammary pheromone as a probe for viability. animal, 1(7), 1026-1032. doi:10.1017/s1751731107000389Rommers, J. M., Boiti, C., Brecchia, G., Meijerhof, R., Noordhuizen, J. P. T. M., Decuypere, E., & Kemp, B. (2004). Metabolic adaptation and hormonal regulation in young rabbit does during long-term caloric restriction and subsequent compensatory growth. Animal Science, 79(2), 255-264. doi:10.1017/s1357729800090111Piles, M., García, M. L., Rafel, O., Ramon, J., & Baselga, M. (2006). Genetics of litter size in three maternal lines of rabbits: Repeatability versus multiple-trait models. Journal of Animal Science, 84(9), 2309-2315. doi:10.2527/jas.2005-622Garcı́a, M. L., & Baselga, M. (2002). Estimation of genetic response to selection in litter size of rabbits using a cryopreserved control population. Livestock Production Science, 74(1), 45-53. doi:10.1016/s0301-6226(01)00280-9Cervera, C., & Carmona, J. F. (s. f.). Nutrition and the climatic environment. Nutrition of the rabbit, 267-284. doi:10.1079/9781845936693.0267Nicodemus, N., Redondo, R., Pérez-Alba, L., Carabaño, R., De Blas, J. C., & García, J. (2010). Effect of level of fibre and type of grinding on the performance of rabbit does and their litters during the first three lactations. Livestock Science, 129(1-3), 186-193. doi:10.1016/j.livsci.2010.01.023Theilgaard, P., Sánchez, J., Pascual, J., Berg, P., Friggens, N. C., & Baselga, M. (2007). Late reproductive senescence in a rabbit line hyper selected for reproductive longevity, and its association with body reserves. Genetics Selection Evolution, 39(2), 207. doi:10.1186/1297-9686-39-2-207Martínez-Paredes, E., Ródenas, L., Martínez-Vallespín, B., Cervera, C., Blas, E., Brecchia, G., … Pascual, J. J. (2012). Effects of feeding programme on the performance and energy balance of nulliparous rabbit does. animal, 6(7), 1086-1095. doi:10.1017/s1751731111002643Baselga M 2004. Genetic improvement of meat rabbits. Programmes and diffusion. In Proceedings of 8th World Rabbit Science Congress, 5–7 September 2004, Puebla, Mexico, pp. 1–13

    Detailed spectroscopy of doubly magic Sn-132

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    The structure of the doubly magic Sn-132(50)82 has been investigated at the ISOLDE facility at CERN, populated both by the beta(-) decay of In-132 and beta(-)-delayed neutron emission of In-133. The level scheme of Sn-13(2) is greatly expanded with the addition of 68 gamma transitions and 17 levels observed for the first time in the beta decay. The information on the excited structure is completed by new gamma transitions and states populated in the beta-n decay of In-133. Improved delayed neutron emission probabilities are obtained both for In-132 and In-133. Level lifetimes are measured via the advanced time-delayed beta gamma gamma(t) fast-timing method. An interpretation of the level structure is given based on the experimental findings and the particle-hole configurations arising from core excitations both from the N = 82 and Z = 50 shells, leading to positive- and negative-parity particle-hole multiplets. The experimental information provides new data to challenge the theoretical description of Sn-132

    Search for chameleons with CAST

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    In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter (βm\beta_{\rm m}) and to photons (βγ\beta_{\gamma}) via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1\,keV to 400\,eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600\,eV. Even though we have not observed any excess above background, we can provide a 95% C.L. limit for the coupling strength of chameleons to photons of βγ ⁣ ⁣1011\beta_{\gamma}\!\lesssim\!10^{11} for 1<βm<1061<\beta_{\rm m}<10^6.Comment: 8 pages, 12 figure

    Efficacy of extended infusion of β-lactam antibiotics for the treatment of febrile neutropenia in haematologic patients : Protocol for a randomised, multicentre, open-label, superiority clinical trial (BEATLE)

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    Altres ajuts: The BEATLE study is a non-commercial, investigator-driven clinical trial funded by the Spanish Network for Research in Infectious Diseases (REIPI RD16/0016/0005; RD16/0016/0010) The Spanish Clinical Research Network (SCReN) provides clinical trial data monitoring and oversees pharmacovigilance (PT17/0017/0010).Background: Febrile neutropaenia (FN) is a very common complication in patients with haematological malignancies and is associated with considerable morbidity and mortality. Broad-spectrum antipseudomonal β-lactam antibiotics (BLA) are routinely used for the treatment of cancer patients with FN. However, the clinical efficacy of BLA may be diminished in these patients because they present with pathophysiological variations that compromise the pharmacokinetic (PK) parameters of these antibiotics. Optimised administration of BLA in prolonged infusions has demonstrated better clinical outcomes in critically ill patients. However, there is a paucity of data on the usefulness of this strategy in patients with FN. The aim of this study is to test the hypothesis that the administration of BLA would be clinically more effective by extended infusion (EI) than by intermittent infusion (II) in haematological patients with FN. Methods: A randomised, multicentre, open-label, superiority clinical trial will be performed. Patients with haematological malignancies undergoing chemotherapy or haematopoietic stem-cell transplant and who have FN and receive empirical antibiotic therapy with cefepime, piperacillin-tazobactam or meropenem will be randomised (1:1) to receive the antibiotic by EI (during half the time of the dosing interval) in the study group, or by II (30 min) in the control group. The primary endpoint will be clinical efficacy, defined as defervescence without modifying the antibiotic treatment administered within the first 5 days of therapy. The primary endpoint will be analysed in the intention-to-treat population. The secondary endpoints will be pharmacokinetic/pharmacodynamic (PK/PD) target achievement, bacteraemia clearance, decrease in C-reactive protein, overall (30-day) case-fatality rate, adverse events and development of a population PK model of the BLA studied. Discussion: Data on the usefulness of BLA administration in patients with FN are scant. Only three clinical studies addressing this issue have been published thus far, with contradictory results. Moreover, these studies had some methodological flaws that limit the interpretation of their findings. If this randomised, multicentre, phase IV, open-label, superiority clinical trial validates the hypothesis that the administration of BLA is clinically more effective by EI than by II in haematological patients with FN, then the daily routine management of these high-risk patients could be changed to improve their outcomes. Trial registration: European Clinical Trials Database: EudraCT 2018-001476-37. ClinicalTrials.gov, ID: NCT04233996
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