Magnified expansion and compression of subpicosecond pulses from a frequency-doubled Nd:YLF laser

Includes bibliographical references.Pulses from a mode-locked frequency-doubled Nd:YLF laser have been spectrally broadened and subsequently expanded to more than 200 ps and recompressed to 750 fs by grating compressors with magnifying telescopes. The new design magnifies the time delay dispersion to a factor 10 times larger than achievable with standard compressors of similar size. The design of the system and its sensitivity to the variations in the position of its optical components is analyzed. The scheme will allow efficient amplification of subpicosecond pulses in dye amplifiers.This work was supported by N.S.F.-CONICET U.S.A./Argentina Cooperative Science Program under Grant INT 8802563, and by the National Science Foundation under Grants ECS 870507 and ECS 8606226. M. C. Marconi was supported by a Fellowship from the Universidad Nacional de Buenos Aires and Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina

Maternally encoded stem-loop-binding protein is degraded in 2-cell mouse embryos by the co-ordinated activity of two separately regulated pathways

AbstractOocytes accumulate mRNAs and proteins that direct early embryonic development. Although subsequent development requires the timely degradation of these maternal products, little is known of the underlying mechanisms. The stem-loop-binding protein (SLBP), which regulates the stability and translation of mRNAs encoding histones and is synthesized during S-phase and degraded during G2 in somatic cells, accumulates during oogenesis. Maternal SLBP is required for mouse embryos to develop beyond the 2-cell stage, but must be degraded to allow the cell-cycle-regulated expression of somatic cells to be established. We report that the quantity of maternal SLBP changes little following fertilization until 44–52 h post-hCG, corresponding to mid-/late G2 of the 2-cell stage, when it decreases by 75%. Efficient degradation requires two pathways. The first requires activity of cyclin-dependent kinases (cdk) and embryonic transcription, preferentially targets nuclear SLBP, and likely corresponds to the pathway that degrades SLBP at G2 in somatic cells. The second does not require cdk activity or transcription and becomes active at 44–52 h post-hCG independently of cell-cycle progression to mid-/late G2, but is not solely regulated by the time elapsed since hCG injection. Thus, the co-ordinated activity of two separately regulated pathways eliminates maternally encoded SLBP from early mouse embryos

Wersync: A WEB-BASED PLATFORM FOR DISTRIBUTED MEDIA SYNCHRONIZATION AND SOCIAL INTERACTION

This paper presents Wersync, which is an adaptive and accurate web-based platform that enables distributed media synchronization and social interaction across remote users. By using Wersync, users can create or join on-going sessions for concurrently consuming the same media content with other remote users in a synchronized manner. Besides, social interaction is provided by sharing the navigation control commands and by integrating synchronized text chat channels. Additionally, two social presence mechanisms have been added to stimulate the participation of external users in on-going sessions on Wersync. By exclusively relying on standard web-based technologies, this platform can guarantee cross-network, cross-platform and crossdevice support, which is a key point in the current heterogeneous media delivery ecosystem

Soft-x-ray interferometer for single-shot laser linewidth measurements

Includes bibliographical references (page 957).A soft-x-ray Mach-Zehnder interferometer configuration that makes use of the time delay introduced by diffraction gratings to conduct single-shot measurements of the linewidth of soft-x-ray laser amplifiers is proposed and analyzed. The scheme was experimentally demonstrated in the near-IR region of the spectrum by measurement of the mode separation of a semiconductor laser. A symmetric configuration with compensated time delays that can be implemented for plasma diagnostics and for evaluating soft-x-ray optics is also discussed

Considerations for developing models of multiphase flow in deformable porous media.

This document summarizes research and planning for the development of a numerical simulation capability for nonisothermal multiphase, multicomponent transport in heterogeneous deformable porous materials. Particular attention is given to describing a mathematical formulation for flow in deformable media and for numerical techniques for dealing with phase transitions. A development plan is formulated to provide a computational capability motivated by current and future needs in geosystems management for energy security

Determinación reciente de la colesterolemia en población adulta sana de Pamplona

RESUMEN: Objetivo: Los objetivos del estudio fueron estimar la proporción de la población adulta sana de Pamplona que había determinado recientemente su colesterolemia e identificar los factores asociados a esta determinación. Métodos: Estudio transversal con entrevista personal a 1066 habitantes de Pamplona seleccionados por muestreo de rutas aleatorias. Se estratificó la ciudad en tres áreas urbanas según el nivel socioeconómico (alto, medio, bajo). La participación fue de un 91,8%. Utilizando como variable dependiente la determinación del colesterol total en los últimos 5 años, y como variables independientes la edad, el sexo, el nivel socioeconómico y el hábito tabáquico, se calcularon las odds ratios (OR) univariantes y se ajustó un modelo de regresión logística. Resultados: El 71,2% de la muestra estudiada (IC 95%: 68,3-74,O) se había determinado el colesterol en los últimos cinco años. Los no fumadores conocían más su colesterolemia que los fumadores con una OR ajustada de 1,38 (IC 95%: 1 ,O-1,9); los hombres lo conocían más que las mujeres (OR ajustada de 1,5; IC 95% 1,l-2,O). El conocimiento era menos frecuente en el grupo de edad 30 años. La determinación de la colesterolemia se daba más en los individuos de nivel socioeconómico medio y alto (OR ajustadas 3,2; IC 95% 2,2-4,7 y 1,6; IC 95% 1,l-2,3), respectivamente. Conclusiones: La determinación reciente del colesterol era más frecuente en individuos de mayor edad y en varones. La determinación de la colesterolemia era menos frecuente en algunos grupos con peor perfil de riesgo coronario (menor nivel socioeconómico y fumadores). Estos resultados sugieren la necesidad de intervenciones para mejorar el conocimientoy control de la colesterolemia en adultos sanos

The Virgo stellar over-density: Mapping the infall of the Sagittarius tidal stream onto the Milky Way disk

The recently discovered Virgo stellar over-density, which expands over \~1000deg^2 perpendicularly to the Galactic disk plane (7< Z <15 kpc, R~7 kpc), is the largest clump of tidal debris ever detected in the outer halo and is likely related with the accretion of a nearby dwarf galaxy by the Milky Way. We carry out N-body simulations of the Sagittarius stream to show that this giant stellar over-density is a confirmation of theoretical model predictions for the leading tail of the Sagittarius stream to cross the Milky Way plane in the Solar neighborhood. Radial velocity measurements are needed to confirm this association and to further constrain the shape of the Milky Way dark matter halo through a new generation of theoretical models. If the identification of Virgo over-density and the Sagittarius leading arm is correct, we predict highly negative radial velocities for the stars of Virgo over-density. The detection of this new portion of the Sagittarius tidal stream would represent an excellent target for the on-going and future kinematic surveys and for dark matter direct detection experiments in the proximity of the Sun.Comment: Accepted for publication in The Astrophysical Journal. Supplementary movies to this paper are available at: http://www.astro.princeton.edu/~mjuric/sgr-virgo

P38 MAPK expression and activation predicts failure of response to CHOP in patients with Diffuse Large B-Cell Lymphoma

The p38 MAPK is constitutively activated in B-NHL cell lines and regulates chemoresistance. Accordingly, we hypothesized that activated p38 MAPK may be associated with the in vivo unresponsiveness to chemotherapy in B-NHL patients.Tissue microarrays generated from eighty untreated patients with Diffused Large B Cell Lymphoma (DLBCL) were examined by immunohistochemistry for the expression of p38 and phospho p38 (p-p38) MAPK. In addition, both Bcl-2 and NF-κB expressions were determined. Kaplan Meier analysis was assessed.Tumor tissues expressed p38 MAPK (82 %) and p-p38 MAPK (30 %). Both p38 and p-p38 MAPK expressions correlated with the high score performance status. A significant correlation was found between the expression p-p38 and poor response to CHOP. The five year median follow-up FFS was 81 % for p38(-) and 34 % for p38(+) and for OS was 83 % for p38(-) and 47 % for p38(+). The p-p38(+) tissues expressed Bcl-2 and 90 % of p-p38(-) where Bcl-2(-). The coexpression of p-p38 and Bcl-2 correlated with pool EFS and OS. There was no correlation between the expression of p-p38 and the expression of NF-κB.The findings revealed, for the first time, that a subset of patients with DLBCL and whose tumors expressed high p-p38 MAPK responded poorly to CHOP therapy and had poor EFS and OS. The expression of p38, p-p38, Bcl2 and the ABC subtype are significant risk factors both p38 and p-p38 expressions remain independent prognostic factors

Picosecond absorption dynamics of photoexcited InGaP epitaxial films

Includes bibliographical references (page 92).The absorption recovery of a photoexcited InGaP epitaxial film 0.4 µm thick was investigated using the pump-probe laser technique and found to have a time constant of 55 ps at room temperature. Measurements done in the temperature range of 300-50 K show the decay of the photoexcited carrier distribution to be dominated by ambipolar diffusion and surface recombination. The measured absorption recovery time constant corresponds to an ambipolar diffusion coefficient D > 2.8 cm2/s and a surface recombination velocity of S > 4 × 105 cm/s at room temperature.This work was supported by the National Science Foundation grant (USA/Argentina) INT 8802563, the Air Force Office of Scientific Research (contract 89-0513), and the Center for Optoelectronic Computing Systems, sponsored by the National Science Foundation/Engineering Research Center grant ECD 9015128 and by the Colorado Advanced Technology Institute, an agency of the State of Colorado. C. S. Menoni acknowledges the support of the National Science Foundation grant ECS 9008899 and the CSU Faculty Research Grant