Biblioteca universitaria, CRAI y alfabetización informacional (María Pinto, Dora Sales y Pilar Osorio)

DURANTE LA CELEBRACIÓN EN LA UNIVERSITAT DE BARCELONA (marzo de 2008) de la Conferencia de primavera de la EUA (European University Association), se ha definido la estrategia a seguir para consolidar los retos del EEES (Espacio Europeo de Educación Superior) y del EEI (Espacio Europeo de Investigación).

Hedgehog signaling governs the development of otic sensory epithelium and its associated innervation in zebrafish

The inner ear is responsible for the perception of motion and sound in vertebrates. Its functional unit, the sensory patch, contains mechanosensory hair cells innervated by sensory neurons from the statoacoustic ganglion (SAG) that project to the corresponding nuclei in the brainstem. How hair cells develop at specific positions, and how otic neurons are sorted to specifically innervate each endorgan and to convey the extracted information to the hindbrain is not completely understood. In this work, we study the generation of macular sensory patches and investigate the role of Hedgehog (Hh) signaling in the production of their neurosensory elements. Using zebrafish transgenic lines to visualize the dynamics of hair cell and neuron production, we show that the development of the anterior and posterior maculae is asynchronic, suggesting they are independently regulated. Tracing experiments demonstrate the SAG is topologically organized in two different neuronal subpopulations, which are spatially segregated and innervate specifically each macula. Functional experiments identify the Hh pathway as crucial in coordinating the production of hair cells in the posterior macula, and the formation of its specific innervation. Finally, gene expression analyses suggest that Hh influences the balance between different SAG neuronal subpopulations. These results lead to a model in which Hh orients functionally the development of inner ear towards an auditory fate in all vertebrate species.

Thermal nucleation and cavitation in 3He and 4He

Density functionals that reproduce the helium liquid-gas interface as a function of temperature have been used, within an improved homogeneous nucleation approach, to investigate thermal nucleation and cavitation in both helium isotopes. The results are compared with available experimental data on cavitation in 3He and 4He. Predictions are made for cavitation in 3He at negative pressures and for nucleation in both isotopes.

Quantum cavitation in liquid helium

Using a functional-integral approach, we have determined the temperature below which cavitation in liquid helium is driven by thermally assisted quantum tunneling. For both helium isotopes, we have obtained the crossover temperature in the whole range of allowed negative pressures. Our results are compatible with recent experimental results on 4He.

Cavitation in 3He-4He liquid mixtures at low temperatures

Bubble formation in solutions of 3He and 4He is studied within a density-functional approach. In particular, the temperature dependence of the cavitation pressure for different 3He concentrations is calculated at low temperatures and compared to that of pure 4He. The presence of Andreev states lowers the surface tension and, consequently, nucleation barriers are drastically reduced. This fact means that even at low 3He concentrations the cavitation process takes place at higher pressures than the spinodal pressure, which is not the case for pure 4He.

Nucleation in supersaturated solutions 3He in 4He at negative pressure.

Depending on the 3He concentration, thermal nucleation in 3-4He supersaturated liquid mixtures at negative pressures may be originated either by bubble or by 3rich drop formation. We have investigated this phenomenon within a density-functional approach, determining the regions in the pressure¿3He-concentration plane where bubbles or drops likely drive the nucleation process. As an illustrative example, we also give the homogeneous nucleation pressure corresponding to 50 and 100 mK temperature.

Generating vortex rings in Bose-Einstein condensates in the line-source approximation

We present a numerical method for generating vortex rings in Bose-Einstein condensates confined in axially symmetric traps. The vortex ring is generated using the line-source approximation for the vorticity, i.e., the curl of the superfluid velocity field is different from zero only on a circumference of a given radius located on a plane perpendicular to the symmetry axis and coaxial with it. The particle density is obtained by solving a modified Gross-Pitaevskii equation that incorporates the effect of the velocity field. We discuss the appearance of density profiles, the vortex core structure, and the vortex nucleation energy, i.e., the energy difference between vortical and ground-state configurations. This is used to present a qualitative description of the vortex dynamics.

K-Rb Fermi-Bose mixtures: Vortex states and sag

We study a confined mixture of bosons and fermions in the quantal degeneracy regime with attractive boson-fermion interaction. We discuss the effect that the presence of vortical states and the displacement of the trapping potentials may have on mixtures near collapse, and investigate the phase stability diagram of the K-Rb mixture in the mean-field approximation supposing in one case that the trapping potentials felt by bosons and fermions are shifted from each other, as it happens in the presence of a gravitational sag, and in another case, assuming that the Bose condensate sustains a vortex state. In both cases, we have obtained an analytical expression for the fermion effective potential when the Bose condensate is in the Thomas-Fermi regime, that can be used to determine the maxima of the Fermionic density. We have numerically checked that the values one obtains for the location of these maxima using the analytical formulas remain valid up to the critical boson and fermion numbers, above which the mixture collapses.

Buenos libros, malas lectoras: la enfermedad moral de las mujeres del siglo XIX

El seu article parteix de l'afirmació que el destí de les dones al segle XIX està marcat, en la ficció, pel "bovarysme", malaltia que proposa que les dones s'emmalalteixen i moren perquè llegeixen malament. El treball analitza aquest problema de la "mala lectura" traçant un recorregut que va des de Fernán Caballero fins a Freud i es comenten alguns episodis de lectura que apareixen en la "Autobiografía" de Gertrudis Gómez de Avellaneda, Clemencia, Amalia, Madame Bovary, María, La regenta i El caso Dora. Her article departs from the statement that the destiny of women in the 19th century is determined, in fiction, by "bovarysm", an illness which proposes that women get sick and die because they read incorrectly. The work analyzes this problem of "bad reading" tracing a journey from Fernán Caballero to Freud, and comments on several episodes about the act of reading, from Gertrudis Gómez de Avellaneda's "Autobiography", Clemencia, Amalia, Madame Bovary, María, La Regenta and Dora's Case.

Buenos libros, malas lectoras: la enfermedad moral de las mujeres del siglo XIX

El seu article parteix de l'afirmació que el destí de les dones al segle XIX està marcat, en la ficció, pel "bovarysme", malaltia que proposa que les dones s'emmalalteixen i moren perquè llegeixen malament. El treball analitza aquest problema de la "mala lectura" traçant un recorregut que va des de Fernán Caballero fins a Freud i es comenten alguns episodis de lectura que apareixen en la "Autobiografía" de Gertrudis Gómez de Avellaneda, Clemencia, Amalia, Madame Bovary, María, La regenta i El caso Dora. Her article departs from the statement that the destiny of women in the 19th century is determined, in fiction, by "bovarysm", an illness which proposes that women get sick and die because they read incorrectly. The work analyzes this problem of "bad reading" tracing a journey from Fernán Caballero to Freud, and comments on several episodes about the act of reading, from Gertrudis Gómez de Avellaneda's "Autobiography", Clemencia, Amalia, Madame Bovary, María, La Regenta and Dora's Case.