6,149 research outputs found
Light charged Higgs boson production at the Large Hadron electron Collider
We study the production of a light charged Higgs boson at the future Large
Hadron electron Collider (LHeC), through the process
considering both decay channels and in the final state. We analyse these processes in the context of the
2-Higgs Doublet Model Type III (2HDM-III) and assess the LHeC sensitivity to
such signals against a variety of both reducible and irreducible
backgrounds. We confirm that prospects for detection in the 2HDM-III are
excellent assuming standard collider energy and luminosity conditions.Comment: 12 pages, 12 figures. Accepted in Physical Review
Vegetación acuática y helofÃtica del Sistema Ibérico septentrional, centro de España
Vegetación acuática y helofÃtica del Sistema Ibérico septentrional, centro de España. En este trabajo, se han reconocido 11 asociaciones y 4 comunidades pertenecientes a las clases fitosociológicas Potametea y Phragmito-Magnocaricetea. El Sistema Ibérico septentrional constituye un lÃmite meridional para comunidades de óptimo centro-europeo -Caricetum rostratae, Caricetum vesicariae y Comunidad de Sparganium emersum-, asà como un lÃmite oriental para comunidades de óptimo atlántico -Ranunculetum omiophylli, Galio broteriani-Caricetum broterianae, Glycerio declinatae-Eleocharitetum-palustris, Glycerio declinatae-Oenanthetum crocatae y Oenantho crocatae-Phalaridetum arundinaceae-
Actualidad editorial de la historia conceptual
El artÃculo se incluye dentro de la revista en un dossier titulado 'FilosofÃa de la historia e historia conceptual II'. En consonancia con este epÃgrafe y bajo el lema de 'Actualidad editorial de la historia conceptual' se agrupan varias reseñas de publicaciones centradas en esta disciplina. En primer lugar, Lorena Rivera León se ocupa del monográfico 'TeorÃa y práctica de la historia conceptual' publicado por la revista 'IsegorÃa', nº 37 (2007), asà como del volumen 'TeorÃas y prácticas de la historia conceptual' compilado por Faustino Oncina Coves y aparecido en CSIC-Plaza y Valdés en 2008. En segundo término, MarÃa G. Navarro presta atención a 'Conceptos. Revista de investigación graciana', nº 5 (2008). Por último, José Manuel Sánchez Fernández se detiene en el libro 'Historia conceptual, Ilustración y modernidad', escrito por Faustino Oncina Coves, que vio la luz en la editorial Anthropos en 2009
Origin of the biphase nature and surface roughness of biogenic calcite secreted by the giant barnacle Austromegabalanus psittacus
The calcite grains forming the wall plates of the giant barnacle Austramegabalanus psittacus have
a distinctive surface roughness made of variously sized crystalline nanoprotrusions covered by
extremely thin amorphous pellicles. This biphase (crystalline-amorphous) structure also penetrates
through the crystal’s interiors, forming a web-like structure. Nanoprotrusions very frequently
elongate following directions related to the crystallographic structure of calcite, in particular,
the directions, which are the strongest periodic bond chains (PBCs) in calcite. We propose
that the formation of elongated nanoprotrusions happens during the crystallization of calcite from
a precursor amorphous calcium carbonate (ACC). This is because biomolecules integrated within the
ACC are expelled from such PBCs due to the force of crystallization, with the consequent formation of
uninterrupted crystalline nanorods. Expelled biomolecules accumulate in adjacent regions, thereby
stabilizing small pellicle-like volumes of ACC. With growth, such pellicles become occluded within
the crystal. In summary, the surface roughness of the biomineral surface reflects the complex shape
of the crystallization front, and the biphase structure provides evidence for crystallization from an
amorphous precursor. The surface roughness is generally explained as resulting from the attachment
of ACC particles to the crystal surface, which later crystallised in concordance with the crystal lattice.
If this was the case, the nanoprotrusions do not reflect the size and shape of any precursor particle.
Accordingly, the particle attachment model for biomineral formation should seek new evidence.Instituto de Salud Carlos III
Spanish Government
CGL2017-85118-P
CGL2015-64683-PUnidad Cientifica de Excelencia of the University of Granada
UCE-PP2016-05Junta de AndalucÃa
RNM363ANID-Chile
FONDECYT 1140938
PCI ANID REDES 170106
PIA ANID ANILLOS ACT17203
Evidence of strong antiferromagnetic coupling between localized and itinerant electrons in ferromagnetic Sr2FeMoO6
Magnetic dc susceptibility () and electron spin resonance (ESR)
measurements in the paramagnetic regime, are presented. We found a Curie-Weiss
(CW) behavior for (T) with a ferromagnetic K and
, this being lower than that expected for
either or ions. The ESR g-factor , is associated with . We obtained an excellent description
of the experiments in terms of two interacting sublattices: the localized
() cores and the delocalized electrons. The coupled equations
were solved in a mean-field approximation, assuming for the itinerant electrons
a bare susceptibility independent on . We obtained
emu/mol. We show that the reduction of for
arises from the strong antiferromagnetic (AFM) interaction between the two
sublattices. At variance with classical ferrimagnets, we found that is
ferromagnetic. Within the same model, we show that the ESR spectrum can be
described by Bloch-Hasegawa type equations. Bottleneck is evidenced by the
absence of a -shift. Surprisingly, as observed in CMR manganites, no
narrowing effects of the ESR linewidth is detected in spite of the presence of
the strong magnetic coupling. These results provide evidence that the magnetic
order in does not originates in superexchange interactions,
but from a novel mechanism recently proposed for double perovskites
Convergence and Stability of a Parametric Class of Iterative Schemes for Solving Nonlinear Systems
[EN] A new parametric class of iterative schemes for solving nonlinear systems is designed.
The third- or fourth-order convergence, depending on the values of the parameter being proven.
The analysis of the dynamical behavior of this class in the context of scalar nonlinear equations
is presented. This study gives us important information about the stability and reliability of the
members of the family. The numerical results obtained by applying different elements of the family
for solving the Hammerstein integral equation and the Fisher¿s equation confirm the theoretical
results.This research was supported by Ministerio de Ciencia, Innovacion y Universidades PGC2018-095896-BC22 (MCIU/AEI/FEDER, UE)Cordero Barbero, A.; Villalba, EG.; Torregrosa Sánchez, JR.; Triguero-Navarro, P. (2021). Convergence and Stability of a Parametric Class of Iterative Schemes for Solving Nonlinear Systems. Mathematics. 9(1):1-18. https://doi.org/10.3390/math9010086S1189
Adiabatic expansions for Dirac fields, renormalization, and anomalies
We introduce an iterative method to univocally determine the adiabatic expansion of the modes of Dirac fields in spatially homogeneous external backgrounds. We overcome the ambiguities found in previous studies and use this new procedure to improve the adiabatic regularization/renormalization scheme. We provide details on the application of the method for Dirac fields living in a four-dimensional Friedmann-Lemaître-Robertson-Walker spacetime with a Yukawa coupling to an external scalar field. We check the consistency of our proposal by working out the conformal anomaly. We also analyze a two-dimensional Dirac field in Minkowski space coupled to a homogeneous electric field and reproduce the known results on the axial anomaly. The adiabatic expansion of the modes given here can be used to properly characterize the allowed physical states of the Dirac fields in the above external backgrounds.This work has been supported by the Spanish MINECO research grants FIS2014-57387-C3-3-P; FIS2014-57387-C3-1-P; FIS2017-84440-C2-2-P; FIS2017-84440-C2-1-P, the COST action CA15117 (CANTATA), supported by COST (European Cooperation in Science and Technology), and the Severo Ochoa Program SEV-2014-0398. A. F. is supported by the Severo Ochoa Ph.D. fellowship SEV-2014-0398-16-1 and the European Social Fund
Effect of band-filling and structural distortions on the Curie temperature of Fe-Mo double perovkites
By means of high resolution neutron powder diffraction at low temperature we
have characterized the structural details of
() and () series of compounds. This study reveals a similar variation of the mean
bond-angle \FeOMo in both series. In contrast, the mean bond-distance \FeMoO\
increases with La but not with Ca substitution. Both series also present a
different evolution of the Curie temperature (), which raises in the La
series and slightly decreases in the Ca one. We thus conclude that the
enhancement of in the La series is due to the electron filling of the
conduction band and a concomitant rising of the density of states at the Fermi
level.Comment: Revtex, 4 Journal pages, 2 figures, 1 tabl
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