Comparison of Interactions Between Control and Mutant Macrophages

This paper presents a preliminary study on macrophages migration in Drosophila embryos, comparing two types of cells. The study is carried out by a framework called macrosight which analyses the movement and interaction of migrating macrophages. The framework incorporates a segmentation and tracking algorithm into analysing motion characteristics of cells after contact. In this particular study, the interactions between cells is characterised in the case of control embryos and Shot3 mutants, where the cells have been altered to suppress a specific protein, looking to understand what drives the movement. Statistical significance between control and mutant cells was found when comparing the direction of motion after contact in specific conditions. Such discoveries provide insights for future developments in combining biological experiments to computational analysis

Slow interfacial reamorphization of Ge films melted by ps laser pulses

Melting and rapid solidification is induced in 50-nm-thick amorphous Ge films on glass substrates by single laser pulses at 583 nm with a duration of 10 ps. The solidification process is followed by means of reflectivity measurements with ns time resolution both at the air/film (front) and the substrate/film (back) interfaces. Due to interference effects between the light reflected at the film-substrate and film-liquid interfaces, the back side reflectivity measurements turn out to be very sensitive to the melt depth induced by the laser pulse and their comparison to optical simulations enables the determination of the solidification dynamics. For low fluences, only a thin layer of the film is melted and solidification occurs interfacially leading to reamorphization of the molten material. The results provide a critical interface velocity for amorphization of ∼4 m/s, much slower than the one that has widely been reported for elementary semiconductors. For high fluences, the molten layer depth approaches the film thickness and the results are consistent with a bulk solidification process. In this case, recalescence effects upon solid phase nucleation become important and lead to the formation of crystallites distributed throughout the whole resolidified volume. © 1998 American Institute of Physics.Jan Siegel acknowledges the funding of the European Community through a grant (ERB40001GT954352) within the Training and Mobility of Researchers Program. This work has been partially supported by CICYT (Spain) under project TIC93-0125.Peer Reviewe

Can the transformation time in phase change optical recording be improved by using femtosecond laser pulses?

CLEO/EUROPE ; EQEC European Quantum Electronics Conference, Munich ICm, Germany, 22-27 June, 2003N

Improved Quantum Hard-Sphere Ground-State Equations of State

The London ground-state energy formula as a function of number density for a system of identical boson hard spheres, corrected for the reduced mass of a pair of particles in a sphere-of-influence picture, and generalized to fermion hard-sphere systems with two and four intrinsic degrees of freedom, has a double-pole at the ultimate \textit{regular} (or periodic, e.g., face-centered-cubic) close-packing density usually associated with a crystalline branch. Improved fluid branches are contructed based upon exact, field-theoretic perturbation-theory low-density expansions for many-boson and many-fermion systems, appropriately extrapolated to intermediate densities, but whose ultimate density is irregular or \textit{random} closest close-packing as suggested in studies of a classical system of hard spheres. Results show substantially improved agreement with the best available Green-function Monte Carlo and diffusion Monte Carlo simulations for bosons, as well as with ladder, variational Fermi hypernetted chain, and so-called L-expansion data for two-component fermions.Comment: 15 pages and 7 figure

Pressure-induced transient structural change of liquid germanium induced by high-energy picosecond laser pulses

The temporal evolution of the reflectivity of germanium at 514 nm upon irradiation with single high-energy picosecond laser pulses has been measured using a streak camera. It is found that, for a well-defined high fluence range, the reflectivity of the laser-induced molten phase attains a value of 0.85, considerably above the value reported for liquid Ge in thermal equilibrium (0.75). This behavior is consistent with a strong densification of the liquid phase remaining after the explosive vaporization of a thin surface layer. Within the specified fluence interval, this anomalously high reflectivity state is independent of the fluence and lasts tens of nanoseconds. Both characteristics point to the presence of a pressure-induced transient structural change in liquid germanium. © 2005 American Institute of Physics.Peer Reviewe

Nanocrystal size dependence of the third-order nonlinear optical response of Cu:Al2O3 thin films

3 pages, 3 figures.Metal nanocomposite thin films formed by Cu nanocrystals embedded in an amorphous Al2O3 host have been synthesized by pulsed laser deposition. The mean nanocrystal diameter d was varied in the range 3.0 ± 0.6 to 6 ± 1 nm. The linear and nonlinear optical properties of the films were studied in the vicinity of the surface plasmon resonance and the size dependence of the third-order nonlinear optical susceptibility of the metal nanocrystals has been determined. The observed dependence (1/d3) indicates that in the studied diameter interval, the nonlinear response is due to quantum confinement effects in which the major contribution is associated with electronic intraband transitions.This work has been partially supported by CICYT (Spain) under TIC 96-0467 project and by the EU under BRPR-CT98-0616 project. We acknowledge Dr. I. Vickridge (University of Paris VI et VII, France) for his assistance with RBS techniques.Peer reviewe

Aproximación al perfil del tutor en línea en una experiencia de b-learning

El presente trabajo aborda el caso de Blended Learning implementado en un programa de licenciatura de la Universidad Autónoma de Tamaulipas, el objetivo fue identificar las características del perfil del tutor en línea desde la percepción de estudiantes y los propios tutores involucrados en la experiencia. La investigación examinó cuatro categorías del perfil del tutor en línea: manejo delasTIC e Internet, formación en entornos educativos virtuales,habilidades de comunicación mediadas por recursos tecnológicos y el diseño de actividades para propiciar el aprendizaje autónomo en ambientes colaborativos. Se aplicaron dos cuestionarios a 45 estudiantes de un total de 67 y 7 docentes de un total de 11, todos ellos participantes en la experiencia blended learning. Los resultados en cuanto a las características del perfil del tutor en línea muestran que la mayoría de los docentes que han participado en el blended learning tienen formación en entornos virtuales. Sin embargo, es necesario incrementar las habilidades de comunicación de estos a un nivel avanzado, respecto a las actividades de enseñanza, aprendizaje y evaluación para entornos virtuales es necesario diversificarlas. Lo que respecta a los estudiantes la mitad de ellos considera su experiencia como satisfactoria aunque indican necesitar una mejor retroalimentación por parte de su tutor.This work is about the case of B-learning implemented in an undergraduate program at the Universidad Autónoma de Tamaulipas, the objetives was to identify the characteristics of the online tutor profile, from the perception of students and tutors themselves involved in the experience. The research examined four categories of online tutor profile: tics and internet management, training in virtual learning environments, communication skills mediated by technological resources and designing activities to encourage independent learning in collaborative environments. The results regarding the characteristics of the online tutor profile show that most teachers who have participated in the blended learning have training in virtual environments. However, it is necessary to increase the communication skills of these at an advanced level, with respect to teaching, learning and assessment for virtual environments is necessary to diversify Regarding students half of them consider their experience as satisfactory while indicating need better feedback from your tutor

"Este gran laberinto: estudios filológicos en el centenario de los “Comentarios Reales”" [Reseña]

Reseña de Arrizabalaga, Carlos, y Prendes Guardiola, Manuel, (eds.) "Este gran laberinto: estudios filológicos en el centenario de los “Comentarios Reales”". Piura: Universidad de Piura/Academia Peruana de la Lengua/Universidad de Navarra, 2009. 156 pp. (ISBN: 978-99-724- 8125-3

Microbial biocatalytic preparation of 2-furoic acid by oxidation of 2-furfuryl alcohol and 2-furanaldehyde with Nocardia corallina

The preparation of 2-furoic acid via oxidation of 2-furfuryl alcohol and 2-furanaldehyde was studied by two procedures using whole cells of Nocardia corallina B-276. We describe a comparison using a batchcultivation (3-L) versus resting cells in potassium phosphate buffer (0.1 M, pH 7.0). In the 3-L bioreactor, 2-furfuryl alcohol (1.35 g/L) was biotransformed after 24 h, to the acid with 81% yield. The bioconversionof 2-furfuryl alcohol using resting cells leads to and almost quantitative yield (98%) of 2-furoic acid in 21 h. 2-furanaldehyde was also oxidized to the 2-furoic acid in 88% yield in 8 h, the ratio substrate:cellswas 1:3.5 (w/w). This method was scaled up to 9 g/L of 2-furanaldehyde