Search results for "Clad"

EVOLUTION OF ENDOGENOUS GIBERELLINS AT DIFFERENT STAGES OF FLOWERING IN RELATION TO RETURN BLOOM OF CACTUS PEAR (OPUNTIA FICUS-INDICA (L.) MILLER)

1998

Abstract The effect of flower emasculation, flower injection with paclobutrazol and the complete removal of the spring flush of flowers and cladodes on the changes in GA 3 concentration at different stages of bloom in flowers and fertile cladodes of Opuntia ficus-indica has been determined. Throughout the bloom period, the concentration of GA 3 was higher in intact flowers and the cladode than in flowers emasculated or injected with paclobutrazol. With the onset of blooming, GA 3 started to accumulate both in the flower and in the fertile cladode, and the highest concentration was measured at full bloom in the flower and in the cladodes whose flowers were not removed. Flower emasculation or…

Fiber laser with combined feedback of core and cladding modes assisted by an intracavity long-period grating

2011

We present a fiber laser made in a single piece of conventional doped-core fiber that operates by combined feedback of the fundamental core mode LP((0,1)) and the high-order cladding mode LP((0,10)). The laser is an all-fiber structure that uses two fiber Bragg gratings and a long-period grating to select the modes circulating in the cavity; the laser emits at the coupling wavelength between the core mode LP((0,1)) and the counterpropagating cladding mode LP((0,10)) in the Bragg gratings. This work demonstrates the feasibility of high-order mode fiber lasers assisted by long-period gratings.

Fiber Bragg gratings with various chirp profiles made in etched tapers

1996

We have studied, both theoretically and experimentally, fibre Bragg gratings with a number of different chirp profiles. These chirp profiles can be easily achieved with a recently demonstrated technique involving a taper of desired profile being etched into the cladding of a fibre. Performances of gratings with linear, quadratic, periodically modulated and step chirp profiles are numerically analysed. The versatility of the technique is demonstrated when linearly and quadratically chirped gratings were made as examples of continuous chirp and gratings with step chirps were made as examples of discontinuously chirped structure.

Fiber laser with cladding-mode feedback based on intracavity long period grating

2011

Cladding modes in fiber laser technology have considerable interest for dispersion compensation [1] and power scaling [2, 3]. A fiber laser with core-cladding conversion was made in convectional Erbium doped fiber by a combination of Bragg and external cavity mirrors and blocking the fundamental mode with a damaged core fiber [2]. Furthermore, the insertion of two long period gratings (LPG) in a fiber Bragg gratings (FBG) Fabry-Perot cavity has been proposed as a potential high-order-mode fiber laser [3]; however, no experimental demonstration has been reported yet because there are no ring-doped fibers available in the market. In this work, we present the first demonstration of an all-fibe…

All-fiber noninterferometric narrow-transmission-bandpass filter

2012

In-fiber mode engineering based on the combination of Bragg and long-period gratings (LPGs) permits the implementation of noninterferometric transmission filters with narrow passbands using standard single-mode fiber. The design of the bandpass filter is based on the coupling between propagating and counterpropagating cladding modes in two fiber Bragg gratings. A LPG located between the Bragg gratings transfers power from the input fundamental mode to a specific cladding mode and recouples the filtered signal to the output fundamental mode. The filter produces a series of narrow passbands of about 30 pm linewidth with a maximum transmittance above 60%, 20 dB isolation, and passband separati…

Chromatic Dispersion Control in Mode-Locked Yb-Doped Fiber Lasers Based on a Microstructured Optical Fiber

2013

We present an experimental study on the use of solid core microstructured optical fibers (MOF) for managing the chromatic dispersion in an Yb-doped fiber laser passively mode-locked by a saturable absorber. The performance of the laser, in terms of pulse width and repetition rate, was investigated as a function of the net cavity dispersion.

Retama species growing in different ecological-climatic areas of northeastern Algeria have a narrow range of rhizobia that form a novel phylogenetic …

2009

International audience; Sixty-seven isolates were isolated from nodules collected on roots of Mediterranean shrubby legumes Retama raetam and Retama sphaerocarpa growing in seven ecological-climatic areas of northeastern Algeria. Genetic diversity of the Retama isolates was analyzed based on genotyping by restriction fragment length polymorphism of PCR-amplified fragments of the 16S rRNA gene, the intergenic spacer (IGS) region between the 16S and 23S rRNA genes (IGS), and the symbiotic genes nifH and nodC. Eleven haplotypes assigned to the Bradyrhizobium genus were identified. Significant biogeographical differentiation of the rhizobial populations was found, but one haplotype was predomin…

PHYLOGENOMIC OF PROSIMIANS: A CLADISTIC APPROACH

2009

Langerhans's cell histiocytosis in old subjects: two rare case reports and review of the literature

2012

Background: Langerhans cell histiocytosis (LCH) is a proliferative disease of histiocyte-like cells that generally affects children; LCH onset is rare in adults; immunohistochemistry is essential to obtain the correct diagnosis, and treatment protocols are controversial. Objective: To describe two new cases of adult onset oral LCH. Case reports: Case 1: a 71-year-old woman, complaining of diffuse oral pain, presented with erythematous mucosal lesions; the panoramic radiograph and CT scan showed multiple mandible radiolucent areas. Immunohistochemical assay for S-100, CD1a and langerin test was essential in reaching the correct diagnosis. Case 2: a 77-year-old female patient presented with a…

A critical comment on ‘ankyroids’ (Echinodermata, Stylophora)

2001

Abstract A recent cladistic analysis of stylophoran echinoderms performed by Parsley suggested that mitrates are polyphyletic and derived from symmetrical cornutes. Parsley erected the order Ankyroida to include all derived cornutes and mitrates. The present paper addresses several significant problems in the data matrix of Parsley's cladistic analysis. Detailed morphological comparisons of various stylophorans suggest that important homologies have been ignored: cornute zygal crest and mitrate septum, adorals, glossal and digital. Subanals are not homologous in mitrates. Identification of plate homologies shows that similar-looking symmetrical thecal outlines have been acquired independent…