Search results for "rapu"

Ultra-short pulse propagation in birefringent fibers—the projection operator method

2008

We examine the propagation of ultra-short optical light pulses in dispersion-managed birefringent fiber transmission systems, in which the pulse dynamics is governed by the coupled higher-order nonlinear Schrodinger equations with higher-order linear and nonlinear optical effects. We derive the equations of motion in terms of pulse parameters such as amplitude, temporal position, width, chirp, frequency and phase, using a projection operator method, and we obtain the spatial dynamical behavior of picosecond and femtosecond pulse parameters. From our detailed analysis, we show that the stimulated Raman scattering has a strong impact on the pulse dynamics.

Parabolic Pulse Amplifiers

2008

International audience; Recent studies in nonlinear optics have led to the discovery of a new class of ultrashort pulse generated in fiber amplifiers by the self-similar propagation of an arbitrary input pulse. These pulses with a parabolic shape and linear chirp, called `optical similaritons,' represent asymptotic solutions of the nonlinear Schrödinger equation with gain, towards which any initial pulse of given energy converges, independently of its intensity profile. Parabolic pulse amplifiers can be easily developed with standard optical fibers and commercial devices. Our goal here is to emphasize the main properties of similaritons and to discuss a few of their numerous new application…

Tailored waveform generation in mode-locked fiber lasers by in-cavity pulse shaper

2014

International audience; We numerically show the possibility of pulse shaping in a mode-locked fiber laser by inclusion of an amplitude-phase spectral filter into the laser cavity. Various advanced temporal waveforms are generated, including parabolic, flat-top and triangular pulses.

Effects of fourth-order fiber dispersion on ultrashort parabolic optical pulses in the normal dispersion regime

2011

International audience; We propose a new method for the generation of both triangular-shaped optical pulses and flat-top, coherent supercontinuum spectra using the effect of fourth-order dispersion on parabolic pulses in a passive, normally dispersive highly nonlinear fiber. The pulse re-shaping process is described qualitatively and is compared to numerical simulations.

Täpläravun (Pacifastacus leniusculus) vaikutus ahventen (Perca fluviatilis) loisyhteisöihin Päijänteellä

2010

Täplärapu (Pacifastacus leniusculus) on tulokaslaji Suomen vesistöissä. Sen on käyttäytymisellään ja ravinnonkäytöllään todettu vähentävän elinalueidensa eliöyhteisöjen monimuotoisuutta. Esimerkiksi Päijänteellä on havaittu joidenkin pohjaeläinten kuten kotiloiden tiheyksien olevan alhaisempia ravun elinalueilla kuin ravuttomilla alueilla. Pohjaselkärangattomat ovat välttämättömiä väli-isäntiä monelle kalan loiselle. Tässä tutkimuksessa selvitettiin, millaisia muutoksia täplärapu voi välillisesti aiheuttaa kalojen loisyhteisöissä muuttamalla pohjaeläinten runsautta. Päijänteeltä valittiin viisi toisistaan riippumatonta ravullista ja ravutonta aluetta. Jokaiselta alueelta pyydettiin mahdolli…

Halévy, fugue d’école und basse donnée

2021

Fuge als satztechnische Ubung – nach Cherubini die ideale Verbindung von strengem Kontrapunkt und freier Komposition – gehorte im 19. Jahrhundert an nahezu allen musikalischen Ausbildungsinstitutionen zum Standardrepertoire, so auch am Conservatoire de Paris: Die Wettbewerbsfugen zum Prix de Rome zeugen vom hohen Niveau der Ausbildung, auch wenn sich die kontrapunktische Ubung immer deutlicher von der kompositorischen Asthetik der Schreibenden entfernte. Anhand von Arbeiten Fromental Halevys wird dieses Niveau aufgezeigt. Dabei kommt sowohl der Schuler Halevy, der seine Wettbewerbsfuge 1819 unter dem Auge Cherubinis verfasste, zu Wort als auch der Lehrer Halevy, dessen Schulerarbeiten einen…

Täpläravun (Pacifastacus leniusculus) ja jokiravun (Astacus astacus) syvyyssuuntainen esiintyminen Lammin Ormajärvellä ja Laukaan Pyhtääjärvellä vuos…

2006

Urinary tract infections in children: EAU/ESPU guidelines.

2015

Context: In 30% of children with urinary tract anomalies, urinary tract infection (UTI) can be the first sign. Failure to identify patients at risk can result in damage to the upper urinary tract.Objective: To provide recommendations for the diagnosis, treatment, and imaging of children presenting with UTI.Evidence acquisition: The recommendations were developed after a review of the literature and a search of PubMed and Embase. A consensus decision was adopted when evidence was low.Evidence synthesis: UTIs are classified according to site, episode, symptoms, and complicating factors. For acute treatment, site and severity are the most important. Urine sampling by suprapubic aspiration or c…

Transient IR spectroscopy identifies key interactions and unravels new intermediates in the photocycle of a bacterial phytochrome.

2020

Phytochromes are photosensory proteins in plants, fungi, and bacteria, which detect red- and far-red light. They undergo a transition between the resting (Pr) and photoactivated (Pfr) states. In bacterial phytochromes, the Pr-to-Pfr transition is facilitated by two intermediate states, called Lumi-R and Meta-R. The molecular structures of the protein in these states are not known and the molecular mechanism of photoconversion is not understood. Here, we apply transient infrared absorption spectroscopy to study the photocycle of the wild-type and Y263F mutant of the phytochrome from Deinococcus radiodurans (DrBphP) from nanoto milliseconds. We identify two sequentially forming Lumi-R states …

Diffractive optics for processing ultrashort light pulses

2011

In this work we combine, in principle, two disjoint optical fields, diffractive optics and ultrashort light radiation. This combination allows us to manipulate in a very unconventional manner femtosecond pulses and, on the other hand, to implement a set of novel applications. In our case we have focused our attention on material processing and biophotonics applications.