Novel mid-infrared dispersive wave generation in gas-filled PCF by transient ionization-driven changes in dispersion

Gas-filled hollow-core photonic crystal fibre (PCF) is being used to generate ever wider supercontinuum spectra, in particular via dispersive wave (DW) emission in the deep and vacuum ultraviolet, with a multitude of applications. DWs are the result of the resonant transfer of energy from a self-compressed soliton, a process which relies crucially on phase matching. It was recently predicted that, in the strong-field regime, the additional transient anomalous dispersion introduced by gas ionization would allow phase-matched DW generation in the mid-infrared (MIR)-something that is forbidden in the absence of free electrons. Here we report for the first time the experimental observation of such MIR DWs, embedded in a 4.7-octave-wide supercontinuum that uniquely reaches simultaneously to the vacuum ultraviolet, with up to 1.7 W of total average power

Design and implementation of an ultrasonic sensor for rapid monitoring of industrial malolactic fermentation of wines

Ultrasound is an emerging technology that can be applied to monitor food processes. However, ultrasonic techniques are usually limited to research activities within a laboratory environment and they are not extensively used in industrial processes. The aim of this paper is to describe a novel ultrasonic sensor designed to monitor physical–chemical changes that occur in wines stored in industrial tanks. Essentially, the sensor consists of an ultrasonic transducer in contact with a buffer rod, mounted inside a stainless steel tube section. This structure allows the ultrasonic sensor to be directly installed in stainless steel tanks of an industrial plant. The operating principle of this design is based on the measurement of ultrasonic velocity of propagation. To test its proper operation, the sensor has been used to measure changes of concentration in aqueous samples and to monitor the progress of a malolactic fermentation of red wines in various commercial wineries. Results show the feasibility of using this sensor for monitoring malolactic fermentations in red wines placed in industrial tanks.Postprint (author's final draft

Bird mortality related to collisions with ski–lift cables: do we estimate just the tip of the iceberg?

Collisions with ski–lift cables are an important cause of death for grouse species living close to alpine ski resorts. As several biases may reduce the detection probability of bird carcasses, the mortality rates related to these collisions are generally underestimated. The possibility that injured birds may continue flying for some distance after striking cables represents a major source of error, known as crippling bias. Estimating the crippling losses resulting from birds dying far from the ski–lift corridors is difficult and it is usually assessed by systematic searches of carcasses on both sides of the ski–lifts. Using molecular tracking, we were able to demonstrate that a rock ptarmigan hen flew up to 600 m after striking a ski–lift cable, a distance preventing its detection by traditional carcasses surveys. Given the difficulty in conducting systematic searches over large areas surrounding the ski–lifts, only an experiment using radio–tagged birds would allow us to estimate the real mortality rate associated with cable collision

Characterization of a birnavirus isolated from diseased turbot cultured in Spain

7 pages, 5 figures, 2 tables.During 1989, light but persistent mortalities were detected in a turbot Scophthalmus maximus L. farm in Galicia (northwestern Spain) and a virus with the characteristics of a birnavirus was isolated. The purpose of this study was to characterize the viral agent and determine the susceptibility of turbot to this virus. Electron microscopic examination revealed that the particles were isometric, hexagonal and unenveloped with an average diameter of 58 to 60 nm. The molecular weights of the RNA segments were 1.9 and 2.0 x 10(up to 6) daltons. The cells most susceptible to the turbot isolate were the CHSE-214, FHM and RTG-2 lines and the optimal temperature range for its replication was 15 to 2OºC. The RNA and polypeptide electropherotypes show that this virus resembles the Ab serotype of infectious pancreatic necrosis virus (IPNV); however, it differs in that it replicates in the FHM cell line and is not neutralized by antisera to the classical serotypes of IPNV. Infectivity trials conducted in turbot of dlfferent sizes indicated that the virus produced mortality only in small fish (2 g), although the larger fish (30 g) harbored the virus for at least 35 d. Fish inoculated with this isolate showed no pancreatic necrosis although necrosis of the hematopoietic elements of the kidney and spleen was detected.This work was supported by Grants MAR 89-0270 from the Comision Interministenal de Ciencia y Tecnologia (CICYT), and by XUGA 70708888 from Xunta de Galicia, Spain. Beatriz Novoa acknowledges the Ministerio de Educacion y Ciencia (Spain) for a research fellowship.Peer reviewe

Influencia de las bacterias psicrótrofas en la actividad proteolítica de la leche

La refrigeración de la leche reduce el ritmo de multiplicación y actividad de los microorganismos, pero ha generado nuevos problemas relacionados con el crecimiento y la actividad de los microorganismos psicrótrofos, que son aquellos que crecen a temperaturas inferiores a 7 °C, independientemente de su temperatura óptima. Estos microorganismos producen enzimas termoestables que degradan algunos componentes de la leche deteriorando su calidad y la de sus derivados, y disminuyendo los rendimientos queseros. Con el fin de evaluar la actividad proteolítica de las bacterias psicrótrofas sobre las caseínas y su relación con la temperatura y tiempo de almacenamiento de la leche, se inocularon diferentes lotes de leche con este tipo de bacterias, hasta obtener recuentos de 104 y 105 unidades formadoras de colonia por mililitro (ufc/ml); como control se utilizó leche que no recibió inoculación con recuento de psicrótrofos de 103 ufc/ml. Después de almacenar la lechea4y7°Cdurante tres y seis días, se evaluó la actividad proteolítica sobre las caseínas. Al almacenar leche durante tres días a 4 y 7 °C, no se presentó actividad proteolítica cuando el recuento inicial de psicrótrofos era del orden de 103 ufc/ml, mientras que cuando dicho recuento fue superior a 104 ufc/ml se observó actividad proteolítica, siendo más intensa a 7 °C que a 4 °C. Con almacenamiento de seis días, solamente la leche conservada a 4 °C con recuento inicial de 103 ufc/ml no presentó actividad proteolítica, los demás tratamientos mostraron gran actividad proteolítica sobre la fracción de caseínas aumentando dicha actividad a medida que aumenta el grado de contaminación

La aculturación como modelo de transición social: los mecanismos de la cristianización

This communication intends to present a theoretical model which can be applied to the process of Christianization in the Iberian Peninsula. We began with the study of the processes of aculturation: external processes (changes, violent or not, of the social groups in power) and an internal process (the rise of a new social class to power). We believe that Christianity is the principal agent in the process of aculturation, and it could be considered as an internal process, except in certain regions in the North of the Peninsula where it presents an external character due to the prevalence of certain modes of pre-Roman production, and as a consequence the process of Christianization en these regions is not as rapid, nor as pacific, as once believed