4,396 research outputs found
Generative Roles: Assessing Sustained Involvement in Generativity
Abstract Generative roles refer to observable, behavioral community positions that embody aspects of teaching and nurturing that are central to the concept of generativity. Two studies are presented that describe generative roles in a community sample and provide psychometric data for a short index of generative roles. The first study also provides reliability and validity data from a second informant. The second study examines generative roles at different stages of adolescence and adulthood. Participants were asked 8 yes/no questions about a variety of community roles. The validity of the GRI was supported by significant correlations with the Loyola Generativity Scale, a widely used measure of generative concern (r=.33), and measures of related constructs. The correlations were similar across age categories. The Generative Roles Index has good psychometric qualities and complements existing measures of generativity by providing behavioral, observable data on roles
Role of the small integrin-binding ligand N-linked glycoprotein (SIBLING), bone sialoprotein (BSP) in bone development and remodeling.
14 pagesInternational audienceMembers of the “small, integrin binding ligand, N-linked glycoprotein” (SIBLING) family, which have both mineral binding and cell binding (integrins) abilities, appear as potent regulators of bone mineralisation and remodeling. Among these, osteopontin (OPN) and bone sialoprotein (BSP) are highly expressed in early bone. Gene knockout of OPN results in increased mineralisation and a resorption defect making mutant mice unable to respond to such challenges as hindlimb unloading. We recently published the phenotype of mice with a knockout of BSP (BSP-/-). We showed that BSP-/- mice are smaller than the wild type counterpart, with a lower bone-formation rate but a higher trabecular volume at 4 month, due to impaired resorption. Lack of BSP results in slower bone repair in a cortical defect model, but does not prevent bone loss due to unloading, in contrast to OPN knockout. These results highlight the specificity of BSP roles in the bone context, as well as the nonredundancy of function of SIBLING family members in skeletal biology
Quantum tunneling in a three dimensional network of exchange coupled single-molecule magnets
A Mn4 single-molecule magnet (SMM) is used to show that quantum tunneling of
magnetization (QTM) is not suppressed by moderate three dimensional exchange
coupling between molecules. Instead, it leads to an exchange bias of the
quantum resonances which allows precise measurements of the effective exchange
coupling that is mainly due to weak intermolecular hydrogen bounds. The
magnetization versus applied field was recorded on single crystals of [Mn4]2
using an array of micro-SQUIDs. The step fine structure was studied via minor
hysteresis loops.Comment: 4 pages, 4 figure
Magnetic field-induced quantum superconductor-insulator transition in
A study of magnetic-field tuned superconductor-insulator transitions in
amorphous thin films shows that quantum
superconductor-insulator transitions are characterized by an unambiguous
signature -- a kink in the temperature profile of the critical magnetic field.
Using this criterion, we show that the nature of the magnetic-field tuned
superconductor-insulator transition depends on the orientation of the field
with respect to the film. For perpendicular magnetic field, the transition is
controlled by quantum fluctuations with indications for the existence of a Bose
insulator; while for parallel magnetic field, the transition is classical,
driven by the breaking of Cooper pairs at the temperature dependent critical
field .Comment: 5 pages, 4 figure
A length scale for the superconducting Nernst signal above T in NbSi
We present a study of the Nernst effect in amorphous superconducting thin
films of NbSi. The field dependence of the Nernst coefficient
above T displays two distinct regimes separated by a field scale set by
the Ginzburg-Landau correlation length. A single function , with the
correlation length as its unique argument set either by the zero-field
correlation length (in the low magnetic field limit) or by the magnetic length
(in the opposite limit), describes the Nernst coefficient. We conclude that the
Nernst signal observed on a wide temperature () and field () range is exclusively generated by short-lived Cooper pairs.Comment: 4 pages, 4 figure
Covariant Poisson equation with compact Lie algebras
The covariant Poisson equation for Lie algebra-valued mappings defined in
3-dimensional Euclidean space is studied using functional analytic methods.
Weighted covariant Sobolev spaces are defined and used to derive sufficient
conditions for the existence and smoothness of solutions to the covariant
Poisson equation. These conditions require, apart from suitable continuity,
appropriate local integrability of the gauge potentials and global weighted
integrability of the curvature form and the source. The possibility of
nontrivial asymptotic behaviour of a solution is also considered. As a
by-product, weighted covariant generalisations of Sobolev embeddings are
established.Comment: 31 pages, LaTeX2
A homomorphism between link and XXZ modules over the periodic Temperley-Lieb algebra
We study finite loop models on a lattice wrapped around a cylinder. A section
of the cylinder has N sites. We use a family of link modules over the periodic
Temperley-Lieb algebra EPTL_N(\beta, \alpha) introduced by Martin and Saleur,
and Graham and Lehrer. These are labeled by the numbers of sites N and of
defects d, and extend the standard modules of the original Temperley-Lieb
algebra. Beside the defining parameters \beta=u^2+u^{-2} with u=e^{i\lambda/2}
(weight of contractible loops) and \alpha (weight of non-contractible loops),
this family also depends on a twist parameter v that keeps track of how the
defects wind around the cylinder. The transfer matrix T_N(\lambda, \nu) depends
on the anisotropy \nu and the spectral parameter \lambda that fixes the model.
(The thermodynamic limit of T_N is believed to describe a conformal field
theory of central charge c=1-6\lambda^2/(\pi(\lambda-\pi)).)
The family of periodic XXZ Hamiltonians is extended to depend on this new
parameter v and the relationship between this family and the loop models is
established. The Gram determinant for the natural bilinear form on these link
modules is shown to factorize in terms of an intertwiner i_N^d between these
link representations and the eigenspaces of S^z of the XXZ models. This map is
shown to be an isomorphism for generic values of u and v and the critical
curves in the plane of these parameters for which i_N^d fails to be an
isomorphism are given.Comment: Replacement of "The Gram matrix as a connection between periodic loop
models and XXZ Hamiltonians", 31 page
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