Panoràmica dels sistemes de gestió de biblioteques al segle XXI

In the past decade, a number of trends have come together in the general sphere of computing that have profoundly affected libraries. The popularisation of the Internet, the appearance of open and interoperable systems, the improvements within graphics and multimedia, and the generalised installation of LANs are some of the events of the period. Taken together, the result has been that libraries have undergone an important functional change, representing the switch from simple information depositories to information disseminators. Integrated library management systems have not remained unaffected by this transformation and those that have not adapted to the new technological surroundings are now referred to as legacy systems. The article describes the characteristics of systems existing in today's market and outlines future trends that, according to various authors, include the disappearance of the integrated library management systems that have traditionally been sold.

Sistemes de gestió de continguts en la gestió del coneixement

Since the second half of the 1990s, knowledge management has taken shape and has been firmly consolidated as a new discipline within the realm of organisations. The principal objective of this work is to determine whether content management systems (CMS) can become the most appropriate technological standard for consolidating this field. The article describes and analyses the major functions (publishing and exploitation) of these new systems. It then examines the field of knowledge management ¿what are the different types of knowledge that we can find within an organisational context¿ and then identifies and analyses the operations critical to managing it appropriately. The article concludes by evaluating the extent to which technological solutions provided by CMS can assist in properly implementing these critical operations.

Disseny, les investigacions sobre la comunicació i la proposada teoria dels signes

L'àmbit de formació universitària és idoni per recuperar de forma més modesta i autocrítica les tesis de la semiòtica i les teories de la comunicació en la seva relació amb els processos del disseny.

La mediació i l'arbitratge de consum: explorar sistemes d'ODR

La utilització dels mitjans alternatius de resolució de conflictes (ADR) en l'àmbit de les reclamacions de consum té un marc legal específic a Espanya -i també a la UE- des del 1993, que deriva de les seves característiques especials. Algunes són d'encuny exclusivament jurídic: es tracta de reclamacions en què el marc legal aplicable és el denominat dret de consum; d'altres tenen un suport bàsicament fàctic: solen tenir poca entitat econòmica, és a dir, entren en la categoria del que denominem small claims, i el fet que les reclamacions -en alguns casos que van en augment- siguin transfrontereres condiciona l'opció entre jurisdicció tradicional i ADR, com també tindrem ocasió d'analitzar. Cal afegir a aquests elements jurídics i fàctics un element important de política legislativa en un àmbit de la UE: els ADR s'entenen com un instrument bàsic per a garantir l'accés dels consumidors a la justícia, però alhora, en l'àmbit del comerç electrònic, són un element de gran transcendència en la creació de la denominada confiança electrònica o e-confidence. Per aquest motiu, s'exploren contínuament proces- sos de resolució en línia de conflictes (on-line dispute resolution, ODR). Els ODR pretenen la màxima eficàcia oferint un suport tècnic capaç de solucionar una controvèrsia amb la intervenció d'un tercer o sense, i dins o fora de l'organització de l'empresari. D'aquesta manera, s'usa un mateix expedient tècnic per a posar en marxa successivament més d'un ADR, o es potencien els mecanismes automàtics que prescindeixen dels conceptes jurídics i, en mig de l'exploració constant, Espanya aposta per l'arbitratge electrònic de consum en el RD 236/2008. A aquests temes ens referirem a continuació.

Ground-state self-consistent calculation of quantum dots under magnetic fields: Addition spectrum

A density-functional self-consistent calculation of the ground-state electronic density of quantum dots under an arbitrary magnetic field is performed. We consider a parabolic lateral confining potential. The addition energy, E(N+1)-E(N), where N is the number of electrons, is compared with experimental data and the different contributions to the energy are analyzed. The Hamiltonian is modeled by a density functional, which includes the exchange and correlation interactions and the local formation of Landau levels for different equilibrium spin populations. We obtain an analytical expression for the critical density under which spontaneous polarization, induced by the exchange interaction, takes place.

Gauge-invariant actions from constraint Hamiltonian dynamics

Dirac's constraint Hamiltonian formalism is used to construct a gauge-invariant action for the massive spin-one and -two fields.

Wave competition in excitable modulated media.

The propagation of an initially planar front is studied within the framework of the photosensitive Belousov-Zhabotinsky reaction modulated by a smooth spatial variation of the local front velocity in the direction perpendicular to front propagation. Under this modulation, the wave front develops several fingers corresponding to the local maxima of the modulation function. After a transient, the wave front achieves a stationary shape that does not necessarily coincide with the one externally imposed by the modulation. Theoretical predictions for the selection criteria of fingers and steady-state velocity are experimentally validated.

Numerical investigation of iso-spectral cavities built from trinagles

We present computational approaches as alternatives to a recent microwave cavity experiment by S. Sridhar and A. Kudrolli [Phys. Rev. Lett. 72, 2175 (1994)] on isospectral cavities built from triangles. A straightforward proof of isospectrality is given, based on the mode-matching method. Our results show that the experiment is accurate to 0.3% for the first 25 states. The level statistics resemble those of a Gaussian orthogonal ensemble when the integrable part of the spectrum is removed.

Canonical transformations theory for presymplectic systems

We develop a theory of canonical transformations for presymplectic systems, reducing this concept to that of canonical transformations for regular coisotropic canonical systems. In this way we can also link these with the usual canonical transformations for the symplectic reduced phase space. Furthermore, the concept of a generating function arises in a natural way as well as that of gauge group.

On the many-time formulation of classical particle dynamics

Starting from the standard one-time dynamics of n nonrelativistic particles, the n-time equations of motion are inferred, and a variational principle is formulated. A suitable generalization of the classical LieKnig theorem is demonstrated, which allows the determination of all the associated presymplectic structures. The conditions under which the action of an invariance group is canonical are studied, and a corresponding Noether theorem is deduced. A formulation of the theory in terms of n first-class constraints is recovered by means of coisotropic imbeddings. The proposed approach also provides for a better understanding of the relativistic particle dynamics, since it shows that the different roles of the physical positions and the canonical variables is not peculiar to special relativity, but rather to any n-time approach: indeed a nonrelativistic no-interaction theorem is deduced.

Vacuum decay in quantum field theory

We study the contribution to vacuum decay in field theory due to the interaction between the long- and short-wavelength modes of the field. The field model considered consists of a scalar field of mass M with a cubic term in the potential. The dynamics of the long-wavelength modes becomes diffusive in this interaction. The diffusive behavior is described by the reduced Wigner function that characterizes the state of the long-wavelength modes. This function is obtained from the whole Wigner function by integration of the degrees of freedom of the short-wavelength modes. The dynamical equation for the reduced Wigner function becomes a kind of Fokker-Planck equation which is solved with suitable boundary conditions enforcing an initial metastable vacuum state trapped in the potential well. As a result a finite activation rate is found, even at zero temperature, for the formation of true vacuum bubbles of size M-1. This effect makes a substantial contribution to the total decay rate.