Diffusion on a solid surface: anomalous is normal

We present a numerical study of classical particles diffusing on a solid surface. The particles motion is modeled by an underdamped Langevin equation with ordinary thermal noise. The particle-surface interaction is described by a periodic or a random two-dimensional potential. The model leads to a rich variety of different transport regimes, some of which correspond to anomalous diffusion such as has recently been observed in experiments and Monte Carlo simulations. We show that this anomalous behavior is controlled by the friction coefficient and stress that it emerges naturally in a system described by ordinary canonical Maxwell-Boltzmann statistics.

Microscopic description of the twist mode in normal and superfluid trapped Fermi gases

We investigate the "twist" mode (rotation of the upper against the lower hemisphere) of a dilute atomic Fermi gas in a spherical trap. The normal and superfluid phases are considered. The linear response to this external perturbation is calculated within the microscopic Hartree-Fock-Bogoliubov approach. In the normal phase the excitation spectrum is concentrated in a rather narrow peak very close to the trapping frequency. In the superfluid phase the strength starts to be damped and fragmented and the collectivity of the mode is progressively lost when the temperature decreases. In the weak-pairing regime some reminiscence of the collective motion still exists, whereas in the strong-pairing regime the twist mode is completely washed out. The disappearance of the twist mode in the strong-pairing regime with decreasing temperature is interpreted in the framework of the two-fluid model.

Lateral instability in normal viscous fingers

We study a low-amplitude, long-wavelength lateral instability of the Saffman-Taylor finger by means of a phase-field model. We observe such an instability in two situations in which small dynamic perturbations are overimposed to a constant pressure drop. We first study the case in which the perturbation consists of a single oscillatory mode and then a case in which the perturbation consists of temporal noise. In both cases the instability undergoes a process of selection.

Phase-field approach to spatial perturbations in normal Saffman-Taylor fingers

We make a numerical study of the effect that spatial perturbations have in normal Saffman-Taylor fingers driven at constant pressure gradients. We use a phase field model that allows for spatial variations in the Hele-Shaw cell. We find that, regardless of the specific way in which spatial perturbations are introduced, a lateral instability develops on the sides of the propagating Saffman-Taylor finger. Moreover, the instability exists regardless of the intensity of spatial perturbations in the cell as long as the perturbations are felt by the finger tip. If, as the finger propagates, the spatial perturbations felt by the tip change, the instability is nonperiodic. If, as the finger propagates, the spatial perturbations felt by the tip are persistent, the instability developed is periodic. In the later case, the instability is symmetrical or asymmetrical depending on the intensity of the perturbation.

Oferta formativa en terapias alternativas y complementarias para la asistencia al parto

Las terapias complementarias y alternativas (TCA) son las intervenciones y prácticas que no forman parte del sistema sanitario convencional. En la obstetricia, su uso es cada día más frecuente. Para asesorar a las gestantes es necesario tener unos conocimientos adecuados al respecto. El objetivo de este estudio es conocer la oferta formativa de las matronas en TCA para la atención al parto mediante una revisión bibliográfica y la consulta de fuentes documentales. El actual programa de formación no las contempla y su aprendizaje depende de motivaciones personales. Existe poca información al respecto. Para recomendarlas y utilizarlas con eficacia y seguridad, es necesario dedicar más recursos a la investigación e incorporarlas en los planes convencionales de estudio.

Oferta formativa en terapias alternativas y complementarias para la asistencia al parto

Las terapias complementarias y alternativas (TCA) son las intervenciones y prácticas que no forman parte del sistema sanitario convencional. En la obstetricia, su uso es cada día más frecuente. Para asesorar a las gestantes es necesario tener unos conocimientos adecuados al respecto. El objetivo de este estudio es conocer la oferta formativa de las matronas en TCA para la atención al parto mediante una revisión bibliográfica y la consulta de fuentes documentales. El actual programa de formación no las contempla y su aprendizaje depende de motivaciones personales. Existe poca información al respecto. Para recomendarlas y utilizarlas con eficacia y seguridad, es necesario dedicar más recursos a la investigación e incorporarlas en los planes convencionales de estudio.

L'escola normal de Barcelona: cent cinquanta anys a la recerca d'un establiment en condiciones pedagògiques

Aquest curs 1996-1997 l'Escola Normal de Mestres de Barcelona commemora els cent cinquanta anys de la seva creació en la recent inaugurada seu del Campus de la Vall d'Hebron i integrada com a Escola Universitaria de Formació del Professorat a la Divisió V. Com a centre universitari i amb la nova llei d'ordenació educativa ha ampliat els àmbits d'actuació pedagogicodocents a sectors que tradicionalment no havien estat de la seva competencia.

Global periodicity conditions for maps and recurrences via Normal Forms

We face the problem of characterizing the periodic cases in parametric families of (real or complex) rational diffeomorphisms having a fixed point. Our approach relies on the Normal Form Theory, to obtain necessary conditions for the existence of a formal linearization of the map, and on the introduction of a suitable rational parametrization of the parameters of the family. Using these tools we can find a finite set of values p for which the map can be p-periodic, reducing the problem of finding the parameters for which the periodic cases appear to simple computations. We apply our results to several two and three dimensional classes of polynomial or rational maps. In particular we find the global periodic cases for several Lyness type recurrences

Conjugation of a Ru(II) Arene Complex to Neomycin or to Guanidinoneomycin Leads to Compounds with Differential Cytotoxicities and Accumulation between Cancer and Normal Cells

A straightforward methodology for the synthesis of conjugates between a cytotoxic organometallic ruthenium(II) complex and amino- and guanidinoglycosides, as potential RNA-targeted anticancer compounds, is described. Under microwave irradiation, the imidazole ligand incorporated on the aminoglycoside moiety (neamine or neomycin) was found to replace one triphenylphosphine ligand from the ruthenium precursor [(η6-p-cym)RuCl(PPh3)2]+, allowing the assembly of the target conjugates. The guanidinylated analogue was easily prepared from the neomycin-ruthenium conjugate by reaction with N,N′-di-Boc-N″-triflylguanidine, a powerful guanidinylating reagent that was compatible with the integrity of the metal complex. All conjugates were purified by semipreparative high-performance liquid chromatography (HPLC) and characterized by electrospray ionization (ESI) and matrix-assisted laser desorptionionization time-of-flight (MALDI-TOF) mass spectrometry (MS) and NMR spectroscopy. The cytotoxicity of the compounds was tested in MCF-7 (breast) and DU-145 (prostate) human cancer cells, as well as in the normal HEK293 (Human Embryonic Kidney) cell line, revealing a dependence on the nature of the glycoside moiety and the type of cell (cancer or healthy). Indeed, the neomycinruthenium conjugate (2) displayed moderate antiproliferative activity in both cancer cell lines (IC50 ≈ 80 μM), whereas the neamine conjugate (4) was inactive (IC50 ≈ 200 μM). However, the guanidinylated analogue of the neomycinruthenium conjugate (3) required much lower concentrations than the parent conjugate for equal effect (IC50 = 7.17 μM in DU-145 and IC50 = 11.33 μM in MCF-7). Although the same ranking in antiproliferative activity was found in the nontumorigenic cell line (3 2 > 4), IC50 values indicate that aminoglycoside-containing conjugates are about 2-fold more cytotoxic in normal cells (e.g., IC50 = 49.4 μM for 2) than in cancer cells, whereas an opposite tendency was found with the guanidinylated conjugate, since its cytotoxicity in the normal cell line (IC50 = 12.75 μM for 3) was similar or even lower than that found in MCF-7 and DU-145 cancer cell lines, respectively. Cell uptake studies performed by ICP-MS with conjugates 2 and 3 revealed that guanidinylation of the neomycin moiety had a positive effect on accumulation (about 3-fold higher in DU-145 and 4-fold higher in HEK293), which correlates well with the higher antiproliferative activity of 3. Interestingly, despite the slightly higher accumulation in the normal cell than in the cancer cell line (about 1.4-fold), guanidinoneomycinruthenium conjugate (3) was more cytotoxic to cancer cells (about 1.8-fold), whereas the opposite tendency applied for neomycinruthenium conjugate (2). Such differences in cytotoxic activity and cellular accumulation between cancer and normal cells open the way to the creation of more selective, less toxic anticancer metallodrugs by conjugating cytotoxic metal-based complexes such as ruthenium(II) arene derivatives to guanidinoglycosides.

The normal distribution in some constrained sample spaces

Phenomena with a constrained sample space appear frequently in practice. This is the case e.g. with strictly positive data, or with compositional data, like percentages or proportions. If the natural measure of difference is not the absolute one, simple algebraic properties show that it is more convenient to work with a geometry different from the usual Euclidean geometry in real space, and with a measure different from the usual Lebesgue measure, leading to alternative models which better fit the phenomenon under study. The general approach is presented and illustrated using the normal distribution, both on the positive real line and on the D-part simplex. The original ideas of McAlister in his introduction to the lognormal distribution in 1879, are recovered and updated

Variación de peso y aporte energético del pasto en vacas de cría en condiciones de montaña: efecto de la época de parto

Se analizaron las variaciones de peso durante la estación de pastoreo de vacas multíparas de raza Parda Alpina con partos en otoño (n = 152) o primavera (n = 123) durante el período 1989-1996. Los animales pasta- ron en áreas boscosas (900-1.500 m, 0,2 vacas/ha) y en pastos supraforestales (1.500-2.200 m, 1,2 vacas/ha). Las vacas con parto en otoño presentaron mayores recuperaciones de peso en pastoreo que las de primavera (0,661 vs 0,071 kg/día, P < 0,001), diferencia observada tanto en los pastos forestales como en los supraforestales. Las variaciones de peso en pastoreo se relacionaron negativamente con las observadas en estabulación (r = –0,20, P < 0,05) y también con el peso a la salida al pasto (r = –0,32, P < 0,05). La contribución energética del pasto a los aportes recibidos anualmente de la dieta fue similar en ambas parideras (43,6 p. 100 y 42,2 p. 100 en otoño y primavera, respectivamente, NS), aunque la pauta de reparto de la energía hacia las funciones fisiológicas en los distintos períodos de manejo fue diferente.

La humanización del trabajo de parto: necesidad de definir el concepto. Revisión de la bibliografía

En los últimos años estamos asistiendo a un cambio en el modelo de atención sanitaria al parto, en el que se pone énfasis en el concepto de humanización asociado a la atención sanitaria al trabajo de parto. A pesar de la relevancia actual del concepto y de sus implicaciones sociosanitarias, hay poca bibliografía que lo defina. El objetivo de este artículo es conocer el origen y el significado del concepto de «humanización del parto» y sus características mediante una revisión bibliográfica de la literatura científica publicada al respecto. Los resultados de la revisión muestran que se trata de un término polisémico, que se basa en tres aspectos fundamentales: convertir a la mujer en el centro de la atención, facilitarle apoyo emocional y prestarle una atención clínica fundamentada en la evidencia científica

La humanización del trabajo de parto: necesidad de definir el concepto. Revisión de la bibliografía

En los últimos años estamos asistiendo a un cambio en el modelo de atención sanitaria al parto, en el que se pone énfasis en el concepto de humanización asociado a la atención sanitaria al trabajo de parto. A pesar de la relevancia actual del concepto y de sus implicaciones sociosanitarias, hay poca bibliografía que lo defina. El objetivo de este artículo es conocer el origen y el significado del concepto de «humanización del parto» y sus características mediante una revisión bibliográfica de la literatura científica publicada al respecto. Los resultados de la revisión muestran que se trata de un término polisémico, que se basa en tres aspectos fundamentales: convertir a la mujer en el centro de la atención, facilitarle apoyo emocional y prestarle una atención clínica fundamentada en la evidencia científica

Conjugation of a Ru(II) Arene Complex to Neomycin or to Guanidinoneomycin Leads to Compounds with Differential Cytotoxicities and Accumulation between Cancer and Normal Cells

A straightforward methodology for the synthesis of conjugates between a cytotoxic organometallic ruthenium(II) complex and amino- and guanidinoglycosides, as potential RNA-targeted anticancer compounds, is described. Under microwave irradiation, the imidazole ligand incorporated on the aminoglycoside moiety (neamine or neomycin) was found to replace one triphenylphosphine ligand from the ruthenium precursor [(η6-p-cym)RuCl(PPh3)2]+, allowing the assembly of the target conjugates. The guanidinylated analogue was easily prepared from the neomycin-ruthenium conjugate by reaction with N,N′-di-Boc-N″-triflylguanidine, a powerful guanidinylating reagent that was compatible with the integrity of the metal complex. All conjugates were purified by semipreparative high-performance liquid chromatography (HPLC) and characterized by electrospray ionization (ESI) and matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) and NMR spectroscopy. The cytotoxicity of the compounds was tested in MCF-7 (breast) and DU-145 (prostate) human cancer cells, as well as in the normal HEK293 (Human Embryonic Kidney) cell line, revealing a dependence on the nature of the glycoside moiety and the type of cell (cancer or healthy). Indeed, the neomycin-ruthenium conjugate (2) displayed moderate antiproliferative activity in both cancer cell lines (IC50 ≈ 80 μM), whereas the neamine conjugate (4) was inactive (IC50 ≈ 200 μM). However, the guanidinylated analogue of the neomycin-ruthenium conjugate (3) required much lower concentrations than the parent conjugate for equal effect (IC50 = 7.17 μM in DU-145 and IC50 = 11.33 μM in MCF-7). Although the same ranking in antiproliferative activity was found in the nontumorigenic cell line (3 2 > 4), IC50 values indicate that aminoglycoside-containing conjugates are about 2-fold more cytotoxic in normal cells (e.g., IC50 = 49.4 μM for 2) than in cancer cells, whereas an opposite tendency was found with the guanidinylated conjugate, since its cytotoxicity in the normal cell line (IC50 = 12.75 μM for 3) was similar or even lower than that found in MCF-7 and DU-145 cancer cell lines, respectively. Cell uptake studies performed by ICP-MS with conjugates 2 and 3 revealed that guanidinylation of the neomycin moiety had a positive effect on accumulation (about 3-fold higher in DU-145 and 4-fold higher in HEK293), which correlates well with the higher antiproliferative activity of 3. Interestingly, despite the slightly higher accumulation in the normal cell than in the cancer cell line (about 1.4-fold), guanidinoneomycin-ruthenium conjugate (3) was more cytotoxic to cancer cells (about 1.8-fold), whereas the opposite tendency applied for neomycin-ruthenium conjugate (2). Such differences in cytotoxic activity and cellular accumulation between cancer and normal cells open the way to the creation of more selective, less toxic anticancer metallodrugs by conjugating cytotoxic metal-based complexes such as ruthenium(II) arene derivatives to guanidinoglycosides.