Effect of wavelength dependence of nonlinearity, gain, and dispersion in photonic crystal fiber amplifiers

Photonic crystal fibers are used in fiber amplifiers and lasers because of the flexibility in the design of mode area and dispersion. However, these quantities depend strongly on the wavelength. The wavelength dependence of gain, nonlinearity and dispersion are investigated here by including the wavelength dependence explicitly in the nonlinear Schr\"odinger equation for photonic crystal fibers with varying periods and hole sizes. The effect of the wavelength dependence of each parameter is studied separately as well as combined. The wavelength dependence of the parameters is shown to create asymmetry to the spectrum and chirp, but to have a moderating effect on pulse broadening. The effect of including the wavelength dependence of nonlinearity in the simulations is demonstrated to be the most significant compared that of dispersion or gain

Secondary habitats are important in biodiversity conservation: a case study on orthopterans along ditch banks

Los hábitats secundarios son importantes en la conservación de la biodiversidad: un estudio práctico sobre los ortópteros en orillas de acequias Se ha demostrado que la biota autóctona puede sobrevivir en hábitats secundarios como cunetas, diques y setos. La finalidad de este estudio es evaluar el valor de las orillas de acequias para la conservación de los ortópteros en un paisaje agrícola en Hungría, a partir del análisis de los datos relativos a la riqueza y la abundancia de especies utilizando modelos mixtos. No encontramos ninguna diferencia en cuanto a la riqueza de especies entre las orillas de acequias aisladas, semiaisladas y en praderas de control. Sin embargo, el grado de aislamiento tuvo un efecto negativo significativo en la abundancia de especies sedentarias. Constatamos que la densidad de vegetación leñosa junto a las orillas de las acequias tenía un efecto negativo en la abundancia total y la abundancia de especies móviles. Se observó la existencia de una relación positiva entre la anchura de las orillas de acequias que estaba cubierta por vegetación y la abundancia de especies del suborden Caelifera y de especies móviles, xerófilas y mesófilas. Nuestros resultados sugieren que la densidad de ortópteros puede ser una medida más sensible de la calidad del hábitat que la riqueza de especies. Concluimos que las orillas de las acequias son un hábitat adecuado para la mayoría de ortópteros, incluidas las especies raras o en peligro de extinción, lo que pone de relieve que debería prestarse más atención a estos y otros hábitats lineales parecidos y que se les debería dar más importancia en la conservación de invertebrados.It has been shown that native biota can survive in secondary habitats such as road verges, dikes and hedges. We aimed to assess the conservation value of ditch banks for orthopterans in an agricultural landscape in Hungary, based on the analyses of species richness and abundance data using mixed–models. We did not find any differences in the species richness between isolated ditch banks, semi–isolated ditch banks and control meadows. The extent of isolation had a significantly negative effect, however, on the abundance of sedentary species. We found that the density of woody vegetation along ditch banks had a negative effect on the total abundance and the abundance of mobile species. Positive relationships were found between the width of ditch bank vegetation and the abundance of Caelifera, mobile, xerophilous and mesophilous species. Our results suggest that the density of orthopterans may be a more sensitive measure for habitat quality than their species richness. We concluded that ditch banks are a suitable habitat for the majority of orthopterans, including rare and endangered species, emphasizing that ditch banks and similar linear habitats should receive more attention and should be given a more prominent role in invertebrate conservation.Los hábitats secundarios son importantes en la conservación de la biodiversidad: un estudio práctico sobre los ortópteros en orillas de acequias Se ha demostrado que la biota autóctona puede sobrevivir en hábitats secundarios como cunetas, diques y setos. La finalidad de este estudio es evaluar el valor de las orillas de acequias para la conservación de los ortópteros en un paisaje agrícola en Hungría, a partir del análisis de los datos relativos a la riqueza y la abundancia de especies utilizando modelos mixtos. No encontramos ninguna diferencia en cuanto a la riqueza de especies entre las orillas de acequias aisladas, semiaisladas y en praderas de control. Sin embargo, el grado de aislamiento tuvo un efecto negativo significativo en la abundancia de especies sedentarias. Constatamos que la densidad de vegetación leñosa junto a las orillas de las acequias tenía un efecto negativo en la abundancia total y la abundancia de especies móviles. Se observó la existencia de una relación positiva entre la anchura de las orillas de acequias que estaba cubierta por vegetación y la abundancia de especies del suborden Caelifera y de especies móviles, xerófilas y mesófilas. Nuestros resultados sugieren que la densidad de ortópteros puede ser una medida más sensible de la calidad del hábitat que la riqueza de especies. Concluimos que las orillas de las acequias son un hábitat adecuado para la mayoría de ortópteros, incluidas las especies raras o en peligro de extinción, lo que pone de relieve que debería prestarse más atención a estos y otros hábitats lineales parecidos y que se les debería dar más importancia en la conservación de invertebrados

Evaluation of sensory and antioxidant properties of commercial coffee substitutes

Sensory profiles of commercial coffee substitutes were determined and their possible interdependences with antioxidant characteristics (FRAP, DPPH, ABTS, and CUPRAC), total polyphenol content, and colour were investigated and compared to coffees. Statistically relevant relations were revealed between certain sensory attributes, colour, and antioxidant capacity. Sensory attributes show distinct patterns for coffees, their blends, and substitutes, but no significant differences between substitutes from different raw materials were found, except for chicory. Although coffees have generally higher antioxidant capacities than their substitutes, these latter, especially chicory-based products, are also valuable antioxidant sources, as only half of them had significantly lower polyphenol and antioxidant contents when compared to coffee. Principal component analysis was applied to reveal possible differentiation pattern between samples, based on both their sensory and antioxidant attributes

Dielectrophoresis of nanoscale dsDNA and humidity effects on its electrical conductivity

The dielectrophoresis method for trapping and attaching nanoscale double-stranded DNA between nanoelectrodes was developed. The method gives a high yield of trapping single or a few molecules only which enables transport measurements at the single molecule level. Electrical conductivity of individual 140-nm-long DNA molecules was measured, showing insulating behavior in dry conditions. In contrast, clear enhancement of conductivity was observed in moist conditions, relating to the interplay between the conformation of DNA molecules and their conductivity.Comment: 4 pages, 2 figure

Minimally invasive tretment methods of lower limb varicosity of C5-C6 classes (CEAP)

ХРОНИЧЕСКАЯ ВЕНОЗНАЯ НЕДОСТАТОЧНОСТЬВАРИКОЗНАЯ БОЛЕЗНЬКОНЕЧНОСТЬ НИЖНЯЯМИНИИНВАЗИВНЫЕ МЕТОДЫ ЛЕЧЕНИЯРАДИОЧАСТОТНАЯ ОБЛИТЕРАЦИЯЭНДОВАЗАЛЬНАЯ ЛАЗЕРНАЯ ОБЛИТЕРАЦИЯЯЗВЫТРОФИЧЕСКИЕ ЯЗВЫКОМПРЕССИОННАЯ ТЕРАПИЯЗАЖИВЛЕНИЕПОСЛЕОПЕРАЦИОННЫЙ ПЕРИО

The future climate characteristics of the Carpathian Basin based on a regional climate model mini-ensemble

Four regional climate models (RCMs) were adapted in Hungary for the dynamical downscaling of the global climate projections over the Carpathian Basin: (i) the ALADIN-Climate model developed by Météo France on the basis of the ALADIN short-range modelling system; (ii) the PRECIS model available from the UK Met Office Hadley Centre; (iii) the RegCM model originally developed at the US National Center for Atmospheric Research, is maintained at the International Centre for Theoretical Physics in Trieste; and (iv) the REMO model developed by the Max Planck Institute for Meteorology in Hamburg. The RCMs are different in terms of dynamical model formulation, physical parameterisations; moreover, in the completed simulations they use different spatial resolutions, integration domains and lateral boundary conditions for the scenario experiments. Therefore, the results of the four RCMs can be considered as a small ensemble providing information about various kinds of uncertainties in the future projections over the target area, i.e., Hungary. After the validation of the temperature and precipitation patterns against measurements, mean changes and some extreme characteristics of these patterns (including their statistical significance) have been assessed focusing on the periods of 2021–2050 and 2071–2100 relative to the 1961–1990 model reference period. The ensemble evaluation indicates that the temperature-related changes of the different RCMs are in good agreement over the Carpathian Basin and these tendencies manifest in the general warming conditions. The precipitation changes cannot be identified so clearly: seasonally large differences can be recognised among the projections and between the two periods. An overview is given about the results of the mini-ensemble and special emphasis is put on estimating the uncertainties in the simulations for Hungary

Anthocyanins identification and quantification in new acai access.

The objective of this work was to identify and quantify the anthocyanins present in new genetically breeding açaí accesse

Charmonium production at neutrino factories

At existing and planned neutrino factories (high energy and high intensity neutrino beam facilities) precision studies of QCD in neutrino-nucleon interactions are a realistic opportunity. We investigate charmonium production in fixed target neutrino experiments. We find that $J/\psi$ production in neutrino-nucleon collision is dominated by the color octet $^3S_1$ NRQCD matrix element in a neutral current process, which is not accessible in photo or leptoproduction. Neutrino experiments at a future Muon Collider will acquire sufficient event rate to accurately measure color octet matrix element contributions. The currently running high energy neutrino experiments, NOMAD and NuTeV could also observe several such events.Comment: 13 pages Latex, with five embedded eps figures. Cosmetic fixups in the figures, otherwise unchange

On the power counting of loop diagrams in general relativity

A class of loop diagrams in general relativity appears to have a behavior which would upset the utility of the energy expansion for quantum effects. We show through the study of specific diagrams that cancellations occur which restore the expected behaviour of the energy expansion. By considering the power counting in a physical gauge we show that the apparent bad behavior is a gauge artifact, and that the quantum loops enter with a well behaved energy expansion.Comment: 29 pages, uses axodraw and epsfig.tex, one small .eps file is included. The full PostScript version is also available as http://het.phast.umass.edu/students/kakukk/powercount_hepth.p

Supersymmetry and Stationary Solutions in Dilaton-Axion Gravity

New stationary solutions of $4$-dimensional dilaton-axion gravity are presented, which correspond to the charged Taub-NUT and Israel-Wilson-Perjes (IWP) solutions of Einstein-Maxwell theory. The charged axion-dilaton Taub-NUT solutions are shown to have a number of interesting properties: i) manifest $SL(2,R)$ symmetry, ii) an infinite throat in an extremal limit, iii) the throat limit coincides with an exact CFT construction. The IWP solutions are shown to admit supersymmetric Killing spinors, when embedded in $d=4,N=4$ supergravity. This poses a problem for the interpretation of supersymmetric rotating solutions as physical ground states. In the context of $10$-dimensional geometry, we show that dimensionally lifted versions of the IWP solutions are dual to certain gravitational waves in string theory.Comment: 23 pages (latex), SU-ITP-94-12, UMHEP-407, QMW-PH-94-1