4,325 research outputs found
Sobre la presència de Melogramma campylosporum a Catalunya
Sobre la presència de Melogramma campylosporum a Catalunya. Es menciona per
primera vegada la presència per a la micoflora de Catalunya de Melogramma campylosporum Fr., un
fong que creix en el nostre cas sobre branques de Corylus avellana. Donat el seu interès corològic,
aportem una descripció detallada de l'espècie, acompanyada d'iconografia.About the presence of Melogramma campylosporum in Catalonia. Melogramma
campylosporum Fr. is a corticicolous fungus first mentioned for the mycoflora of Catalonia. In our
case, it grows on branches of Corylus avellana and given its chorological interest, we provide a
detailed description of the species, accompanied by iconography.Sobre la presencia de Melogramma campylosporum en Cataluña. Se menciona por
primera vez, la presencia para la micoflora de Cataluña de Melogramma campylosporum Fr., un hongo
que crece en nuestro caso sobre ramas de Corylus avellana. Dado su interés corológico, aportamos una
descripción detallada de la especie, acompañada de iconografía
Factorization invariants in half-factorial affine semigroups
Let be the monoid generated by We introduce the
homogeneous catenary degree of as the smallest with the following property: for each and any two factorizations of
, there exists factorizations of such that, for every where is the
usual distance between factorizations, and the length of is less than or equal to
We prove that the homogeneous catenary degree of
improves the monotone catenary degree as upper bound for the ordinary catenary
degree, and we show that it can be effectively computed. We also prove that for
half-factorial monoids, the tame degree and the -primality coincide,
and that all possible catenary degrees of the elements of an affine semigroup
of this kind occur as the catenary degree of one of its Betti elements.Comment: 8 pages, 1 figur
Thing Complex Fuzzy Systems by Supervised Learning Algorithms
Tuning a fuzzy system to meet a given set of inpuffoutput
patterns is usually a difficult task that involves many parameters.
This paper presents an study of different approaches
that can be applied to perform this tuning process automatically,
and describes a CAD tool, named xfsl, which allows
applying a wide set of these approaches: (a) a large number
of supervised learning algorithms; (b) different processes to
simplify the learned system; (c) tuning only specific parameters
of the system; (d) the ability to tune hierarchical fuzzy
systems, systems with continuous output (like fuzzy controller)
as well as with categorical output (like fuzzy classifiers),
and even systems that employ user-defined fuzzy
functions; and, finally, (e) the ability to employ this tuning
within the design flow of a fuzzy system, because xfsl is integrated
into the fuzzy system development environment
Xfuzzy 3.0.Comisión Interministerial de Ciencia y Tecnología TIC2001-1726-C02-0
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
Engineered microenvironments for synergistic VEGF - integrin signalling during vascularization
We have engineered polymer-based microenvironments that promote vasculogenesis both in vitro and in vivo through synergistic integrin-growth factor receptor signalling. Poly(ethyl acrylate) (PEA) triggers spontaneous organization of fibronectin (FN) into nanonetworks which provide availability of critical binding domains. Importantly, the growth factor binding (FNIII12-14) and integrin binding (FNIII9-10) regions are simultaneously available on FN fibrils assembled on PEA. This material platform promotes synergistic integrin/VEGF signalling which is highly effective for vascularization events in vitro with low concentrations of VEGF. VEGF specifically binds to FN fibrils on PEA compared to control polymers (poly(methyl acrylate), PMA) where FN remains in a globular conformation and integrin/GF binding domains are not simultaneously available. The vasculogenic response of human endothelial cells seeded on these synergistic interfaces (VEGF bound to FN assembled on PEA) was significantly improved compared to soluble administration of VEGF at higher doses. Early onset of VEGF signalling (PLCγ1 phosphorylation) and both integrin and VEGF signalling (ERK1/2 phosphorylation) were increased only when VEGF was bound to FN nanonetworks on PEA, while soluble VEGF did not influence early signalling. Experiments with mutant FN molecules with impaired integrin binding site (FN-RGE) confirmed the role of the integrin binding site of FN on the vasculogenic response via combined integrin/VEGF signalling. In vivo experiments using 3D scaffolds coated with FN and VEGF implanted in the murine fat pad demonstrated pro-vascularization signalling by enhanced formation of new tissue inside scaffold pores. PEA-driven organization of FN promotes efficient presentation of VEGF to promote vascularization in regenerative medicine applications
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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