Search results for "Libraries"
showing 10 items of 255 documents
Bibliotecas versus librerías de grandes superficies comerciales : usuarios y clientes
2007
En este artículo se analiza la polémica que surgió en Estados Unidos en 1998 entre la pervivencia de la biblioteca tradicional y una nueva forma de entender la información en las librerías de las grandes superficies comerciales. Después de una breve historia del origen de las grandes librerías y su posterior integración en las grandes superficies comerciales se examina como ha influido en la biblioteca esta nueva práctica empresarial. Cómo pretende convertir al usuario en cliente y obligarle a pagar por determinados servicios bibliotecarios. Por último, reflexiona de la manera que la popularización del ordenador y la irrupción de Internet han reforzado el papel de la biblioteca como centro …
University of Latvia
2012
Prepared for publication in 2012 by International Relations Department, Public Relations Department, University of Latvia Press.
A natural-like synthetic small molecule impairs bcr-abl signaling cascades and induces megakaryocyte differentiation in erythroleukemia cells
2013
Over the past years, we synthesized a series of new molecules that are hybrids of spirocyclic ketones as complexity-bearing cores with bi- and ter-phenyls as privileged fragments. Some of these newly-shaped small molecules showed antiproliferative, pro-apoptotic and differentiating activity in leukemia cell lines. In the present study, to investigate more in depth the mechanisms of action of these molecules, the protein expression profiles of K562 cells treated with or without the compounds IND_S1, MEL_T1, IND_S7 and MEL_S3 were analyzed using two-dimensional gel electrophoresis coupled with mass spectrometry. Proteome comparisons revealed several differentially expressed proteins, mainly r…
Forward doubly-virtual Compton scattering off the nucleon in chiral perturbation theory: The subtraction function and moments of unpolarized structur…
2020
The forward doubly-virtual Compton scattering (VVCS) off the nucleon contains a wealth of information on nucleon structure, relevant to the calculation of the two-photon-exchange effects in atomic spectroscopy and electron scattering. We report on a complete next-to-leading-order (NLO) calculation of low-energy VVCS in chiral perturbation theory ($\chi$PT). Here we focus on the unpolarized VVCS amplitudes $T_1(\nu, Q^2)$ and $T_2(\nu, Q^2)$, and the corresponding structure functions $F_1(x, Q^2)$ and $F_2(x,Q^2)$. Our results are confronted, where possible, with "data-driven" dispersive evaluations of low-energy structure quantities, such as nucleon polarizabilities. We find significant dis…
Owning (and reading?) politeness books in the eighteenth century: an analysis through private libraries
2020
Este artículo explora la presencia en bibliotecas privadas españolas —y algunas americanas— del siglo XVIII de la literatura de urbanidad, considerada en un sentido amplio que incluye no solo manuales de civilidad propiamente dichos, sino también ensayos, periódicos, obras de educación, filosofía moral, medicina, ficción o viajes, en las que la reflexión sobre las costumbres y las pautas de vida civilizadas constituyó un eje importante. Aunque poseer libros no equivale a leerlos, el análisis de una veintena de inventarios y catálogos, complementados en ciertos casos con notas y recomendaciones de lectura, proporciona ciertos indicios sobre el lugar que la civilidad ocupó en las preocupacion…
Hadronic light-by-light contribution to $$(g-2)_\mu $$ ( g - 2 ) μ from lattice QCD with SU(3) flavor symmetry
2020
We perform a lattice QCD calculation of the hadronic light-by-light contribution to $$(g-2)_\mu $$ ( g - 2 ) μ at the SU(3) flavor-symmetric point $$m_\pi =m_K\simeq 420\,$$ m π = m K ≃ 420 MeV. The representation used is based on coordinate-space perturbation theory, with all QED elements of the relevant Feynman diagrams implemented in continuum, infinite Euclidean space. As a consequence, the effect of using finite lattices to evaluate the QCD four-point function of the electromagnetic current is exponentially suppressed. Thanks to the SU(3)-flavor symmetry, only two topologies of diagrams contribute, the fully connected and the leading disconnected. We show the equivalence in the continu…
Leading hadronic contribution to (g−2)μ from lattice QCD with Nf=2+1 flavors of O(a) improved Wilson quarks
2019
The comparison of the theoretical and experimental determinations of the anomalous magnetic moment of the muon (g−2)μ constitutes one of the strongest tests of the Standard Model at low energies. We compute the leading hadronic contribution to (g−2)μ using lattice QCD simulations employing Wilson quarks. Gauge field ensembles at four different lattice spacings and several values of the pion mass down to its physical value are used. We apply the O(a) improvement program with two discretizations of the vector current to better constrain the approach to the continuum limit. The electromagnetic current correlators are computed in the time-momentum representation. In addition, we perform auxilia…
Rational irreducible characters and rational conjugacy classes in finite groups
2007
We prove that a finite group G G has two rational-valued irreducible characters if and only if it has two rational conjugacy classes, and determine the structure of any such group. Along the way we also prove a conjecture of Gow stating that any finite group of even order has a non-trivial rational-valued irreducible character of odd degree.
Homology of pseudodifferential operators on manifolds with fibered cusps
2003
The Hochschild homology of the algebra of pseudodifferential operators on a manifold with fibered cusps, introduced by Mazzeo and Melrose, is studied and computed using the approach of Brylinski and Getzler. One of the main technical tools is a new convergence criterion for tri-filtered half-plane spectral sequences. Using trace-like functionals that generate the 0 0 -dimensional Hochschild cohomology groups, the index of a fully elliptic fibered cusp operator is expressed as the sum of a local contribution of Atiyah-Singer type and a global term on the boundary. We announce a result relating this boundary term to the adiabatic limit of the eta invariant in a particular case.
Understanding star-fundamental algebras
2021
Star-fundamental algebras are special finite dimensional algebras with involution ∗ * over an algebraically closed field of characteristic zero defined in terms of multialternating ∗ * -polynomials. We prove that the upper-block matrix algebras with involution introduced in Di Vincenzo and La Scala [J. Algebra 317 (2007), pp. 642–657] are star-fundamental. Moreover, any finite dimensional algebra with involution contains a subalgebra mapping homomorphically onto one of such algebras. We also give a characterization of star-fundamental algebras through the representation theory of the symmetric group.