5,393 research outputs found
Unitarization effects in EFT predictions of WZ scattering at the LHC
Effective field theories are an incredibly powerful tool in order to study
and understand the true nature of the symmetry breaking sector dynamics of the
Standard Model. However, they can suffer from some theoretical problems such as
that of unitarity violation. Nevertheless, in order to interpret experimental
data correctly a fully unitary prescription is needed. To this purpose,
unitarization methods are addressed, but each of them leads to a different
(unitary) prediction. Because of this, there is an inherent theoretical
uncertainty in the determination of the effective field theory parameters due
to the choice of one unitarization scheme. In this work, we quantify this
uncertainty assuming a strongly interacting electroweak symmetry breaking
sector, described by the effective electroweak chiral Lagrangian. We focus on
the bosonic part of this effective Lagrangian and choose in particular the WZ
scattering as our main VBS channel to study the sensitivity to new physics at
the LHC. We study the different predictions of various well known unitarization
methods, considering the full coupled system of helicity amplitudes, and
construct the 95\% confidence level exclusion regions for the most relevant
electroweak chiral Lagrangian parameters, given by the two anomalous quartic
gauge couplings and . This provides a consistent analysis of the
different constraints on EChL parameters that can be achieved by using
different unitarization methods in a combined way.Comment: 25 pages, 8 figures (20 plots), this version matches the published
article in Phys. Rev.
The first CO+ image: Probing the HI/H2 layer around the ultracompact HII region Mon R2
The CO+ reactive ion is thought to be a tracer of the boundary between a HII
region and the hot molecular gas. In this study, we present the spatial
distribution of the CO+ rotational emission toward the Mon R2 star-forming
region. The CO+ emission presents a clumpy ring-like morphology, arising from a
narrow dense layer around the HII region. We compare the CO+ distribution with
other species present in photon-dominated regions (PDR), such as [CII] 158 mm,
H2 S(3) rotational line at 9.3 mm, polycyclic aromatic hydrocarbons (PAHs) and
HCO+. We find that the CO+ emission is spatially coincident with the PAHs and
[CII] emission. This confirms that the CO+ emission arises from a narrow dense
layer of the HI/H2 interface. We have determined the CO+ fractional abundance,
relative to C+ toward three positions. The abundances range from 0.1 to
1.9x10^(-10) and are in good agreement with previous chemical model, which
predicts that the production of CO+ in PDRs only occurs in dense regions with
high UV fields. The CO+ linewidth is larger than those found in molecular gas
tracers, and their central velocity are blue-shifted with respect to the
molecular gas velocity. We interpret this as a hint that the CO+ is probing
photo-evaporating clump surfaces.Comment: The main text has 4 pages, 2 pages of Appendix, 4 figures, 1 table.
Accepted for publication in Astronomy and Astrophysics letter
Variable variance Preisach model for multilayers with perpendicular magnetic anisotropy
We present a variable variance Preisach model that fully accounts for the different magnetization processes of a multilayer structure with perpendicular magnetic anisotropy by adjusting the evolution of the interaction variance as the magnetization changes. We successfully compare in a quantitative manner the results obtained with this model to experimental hysteresis loops of several [CoFeB/Pd]_{n} multilayers. The effect of the number of repetitions and the thicknesses of the CoFeB and Pd layers on the magnetization reversal of the multilayer structure is studied, and it is found that many of the observed phenomena can be attributed to an increase of the magnetostatic interactions and subsequent decrease of the size of the magnetic domains. Increasing the CoFeB thickness leads to the disappearance of the perpendicular anisotropy, and such a minimum thickness of the Pd layer is necessary to achieve an out-of-plane magnetization.Knut and Alice Wallenberg FoundationSemiconductor Research Corporation. Center for Spintronic Materials, Interfaces, and Novel ArchitecturesMicroelectronics Advanced Research Corporatio
An index-based method for evaluating seismic retrofitting techniques. Application to a reinforced concrete primary school in Huelva
A project named PERSISTAH (Projetos de Escolas Resilientes aos SISmos no TerritĂłrio do Algarve e de Huelva, in Portuguese) is being developed. It aims to cooperatively assess and improve the seismic vulnerability of primary schools in the Algarve (Portugal) and Huelva (Spain). A large number of schools have to be analysed. In order to determine which seismic retrofitting technique is optimal, an index-based method is presented in this paper. It considers three parameters: first, the efficiency of the seismic retrofitting technique in relation to the structural improvement obtained; second, the cost of the implementation of the retrofitting technique; and third, the architectural impact. It should be mentioned that a specific measurement for each solution according to its geometry has been performed. Also, coefficients to consider the singularities of each analysis and the importance of the parameters (number of buildings, typology, available funds, etc.) in the study are considered. The most representative primary school of Huelva has been chosen to test the index-based method. The most suitable retrofitting techniques for this type of buildings have been tested. The retrofitting technique which most increased the seismic performance has been the addition of X and V bracings within the building's bays. Furthermore, the analyses have revealed that adding the retrofitting elements in the most vulnerable direction of the building provides a high efficiency. The results have also shown that implementing techniques of lower architectural impact gives acceptable results. The analysis of the mean damage level index has shown that the building would experiment a severe damage. All the retrofitting techniques applied have reduced it, at least, up to moderate damage. Finally, it should be noted that the position of the retrofitting elements is also paramount for providing an optimal retrofitting.info:eu-repo/semantics/publishedVersio
Differential Immune-Reactivity and Subcellular Distribution Reveal the Multifunctional Character of Profilin in Pollen as Major Effect of Sequences Polymorphism
Trabajo presentado al Annual Meeting of the American Society of Agronomy and Crop Science Society and Soil Science Society of America, celebrado en Cincinnati (USA) del 21 al 24 de octubre de 2012.Profilin, one of the major allergen (Ole e 2) of olive (Olea europaea L.) pollen, are broadly distributed actin-monomer-binding proteins (ABP). They display a major regulatory role in actin cytoskeleton dynamics, driving cell morphogenesis, sexual reproduction, and translating signals into cellular responses to different environmental stresses. Plants exhibit multiple profilin isoforms w ith distinctive biochemical properties, and differentially regulated. How ever, it is still an open question w hether these profilin isoforms, generated by multiple gene sequence polymorphism, are functionally different, as well as the role of that polymorphism in pollen allergy. Particularly, in differential epitopes generation, profilin isoforms sensitization and cross-reactivity among cultivars, and even among species. In the present study, w e have used mature pollen from olive, birch, hazel, timothy-grass, and maize, in addition to olive germinating pollen and seeds, w ith the aim to analyze the immune-reactivity and subcellular localization of profilin by using polyclonal and specific isoforms antibodies against olive and maize profilins.
The results show ed immune-reactivity differences betw een the five species analyzed, betw een olive cultivars, as w ell as between reproductive and vegetative profilins. Furthermore, the existence of different profilin isoforms w as revealed along pollen germination stages. A differential subcellular distribution of profilin isoforms w as found in olive pollen. They w ere localized in the nucleus, pollen aperture regions, pollen and tube w alls and pollen tip, in addition to a general cytoplasmic distribution, in comparison to controls. Data suggest that profilin family might contain numerous functionally distinctive isoforms, spatial-temporal differentially expressed and regulated during vegetative development, pollen maturation and pollen tube grow th. Furthermore, differential immune-reactivity revealed in the study might point out the involvement of common shared and specific epitopes, generated by sequence polymorphism, in differential olive pollen cultivar sensitization of allergenic patients, and cross-reaction to pollen from different species.This study was supported by the following European Regional Development Fund cofinanced grants: MCINN BFU 2004-00601/BFI, BFU 2008-00629, BFU2011-22779, CICE (Junta de AndalucĂa) P2010-CVI15767, P2010-AGR6274, P2011-CVI-7487, P2011-CVI-7487, and by the coordinated project Spain/Germany MEC HA2004-0094.Peer reviewe
Recent results from the canfranc dark matter search with germanium detectors
Two germanium detectors are currently operating in the Canfranc Underground
Laboratory at 2450 m.w.e looking for WIMP dark matter. One is a 2 kg 76Ge IGEX
detector (RG-2) which has an energy threshold of 4 keV and a low-energy
background rate of about 0.3 c/keV/kg/day. The other is a small (234 g) natural
abundance Ge detector (COSME), of low energy threshold (2.5 keV) and an energy
resolution of 0.4 keV at 10 keV which is looking for WIMPs and for solar
axions. The analysis of 73 kg-days of data taken by COSME in a search for solar
axions via their photon Primakoff conversion and Bragg scattering in the Ge
crystal yields a 95% C.L. limit for the axion-photon coupling g < 2.8 10^-9
GeV^-1. These data, analyzed for WIMP searches provide an exclusion plot for
WIMP-nucleon spin-independent interaction which improves previous plots in the
low mass region. On the other hand, the exclusion plot derived from the 60
kg-days of data from the RG-2 IGEX detector improves the exclusion limits
derived from other ionization (non thermal) germanium detector experiments in
the region of WIMP masses from 30 to 100 GeV recently singled out by the
reported DAMA annual modulation effect.Comment: 6 pages, talk given at IDM2000, York, September 200
Improving the activity in hydrodechlorination of Pd/C catalysts by nitrogen doping of activated carbon supports
Aqueous phase 4-chlorophenol hydrodechlorination reaction was used to study the effect of N-doping of activated carbon support on the catalytic activity of Pd catalysts. Activated carbon was doped using pyridine and 1,10-phenantroline, reaching nitrogen contents of 0.42-1.22 and 1.35-4.19 % (w), respectively. All catalysts (0.75 % Pd w, carbon basis) showed relatively large Pd nanoparticles (35-55nm), but they exhibited fast and complete 4-chlorophenol disappearance in batch experiments. In runs at 30°C 4-chlorophenol disappearance was mainly ascribed to hydrodechlorination, although N-doping of the support also increased adsorption. Catalysts with supports doped with pyridine yielded higher 4-chlorophenol disappearance rate in spite of lower bulk nitrogen content, however they showed higher concentration of nitrogen species at the external surface and lower loss of surface area during the doping. 4-chlorophenol disappearance rate was boosted at 60°C, with minor differences between catalysts with undoped and N-doped supports, but generation of cyclohexanone was only observed for the ones with doped support. Phenol generation simultaneous to 4-chlorophenol disappearance was observed with all the catalysts. However, subsequent hydrogenation to cyclohexanone ocurred only with the catalysts supported on N-doped activated carbonThe authors greatly appreciate the financial support of this research from the Spanish Ministry of Economy and Competitiveness through the project CTQ2012-3282
Detection of a putative TetR-like gene related to Mycobacterium bovis BCG growth in cholesterol using a gfp-transposon mutagenesis system
In vitro transposition is a powerful genetic tool for identifying mycobacterial virulence genes and studying virulence factors in relation to the host. Transposon shuttle mutagenesis is a method for constructing stable insertions in the genome of different microorganisms including mycobacteria. Using an IS1096 derivative, we have constructed the Tngfp, a transposon containing a promoterless green fluorescent protein (gfp) gene. This transposon was able to transpose randomly in Mycobacterium bovis BCG. Bacteria with a single copy of the gfp gene per chromosome from an M. bovis BCG::Tngfp library were analyzed and cells exhibiting high levels of fluorescence were detected by flow cytometry. Application of this approach allowed for the selection of a mutant, BCG_2177c::Tngfp (BCG-Tn), on the basis of high level of long-standing fluorescence at stationary phase. This BCG-Tn mutant showed some particular phenotypic features compared to the wild type strain, mainly during stationary phase, when cholesterol was used as a sole carbon source, thus supporting the relationships of the targeted gene with the regulation of cholesterol metabolism in this bacteria. This approach showed that Tngfp is a potentially useful tool for studying the involvement of the targeted loci in metabolic pathways of mycobacteria
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