Study of the bijective relationship between the single and bundle cotton fiber mechanical properties

The characterization of cotton fiber is very complex due to the growing and harvesting conditions of the cotton plant. It is very important for breeders to understand the relationships that may exist between specific fiber properties, overall fiber quality and yam quality. All of these factors interact and are critical to the development of cottons that can compete in a global market. Understanding these interactions will allow breeders to more effectlvely use fiber data for selection purposes to improve yarn quality. In this paper, we will focus on the-relationships between fibers' mechanical properties and yarns' ones by studying their relative behavior and the relationship between single cotton fibers and cotton fiber bundles. For this purpose, three different types or cotton fibers will be studied. These cottons were chosen from a list of twelve cottons covering a large panel of varieties and physical properties as maturity, fineness, micronaire, length, etc… as shown in Figure1 and 2. Classification per length classes and linear densities will be done in order to enlarge the scale when making plant selection. Analogical models based on springs, dashpots elements as kelvin Voigt models will be presented for each length class for single fibres and fiber bundles in order to provide additional information on their bebavior. With single fiber analogical models and fiber bundle analogical models, a relationship linking these two models will be studied. This relationship should be a bijective relationship. Properties evaluated will include elongation, single and bundle tenacities, work of rupture, etc… Fibres bundles quality will be an effective tool in predicting yarn quality and spinning performances

Method of making conical fiber optical components

Improved method for producing fused-fiber optical components is described. These components have a frustro-conical shape and provide high-quality light transmission with high resolution capabilities. Fiber optical components can be used in precision optical systems, such as in certain camera applications

High-resolution and broadband all-fiber spectrometers

The development of optical fibers has revolutionized telecommunications by enabling long-distance broad-band transmission with minimal loss. In turn, the ubiquity of high-quality low-cost fibers enabled a number of additional applications, including fiber sensors, fiber lasers, and imaging fiber bundles. Recently, we showed that a mutlimode optical fiber can also function as a spectrometer by measuring the wavelength-dependent speckle pattern formed by interference between the guided modes. Here, we reach a record resolution of 1 pm at wavelength 1500 nm using a 100 meter long multimode fiber, outperforming the state-of-the-art grating spectrometers. we also achieved broad-band operation with a 4 cm long fiber, covering 400 nm - 750 nm with 1 nm resolution. The fiber spectrometer, consisting of the fiber which can be coiled to a small volume and a monochrome camera that records the speckle pattern, is compact, lightweight, and low cost while providing ultrahigh resolution, broad bandwidth and low loss.Comment: 12 pages, 6 figure

Genetical genomics dissection of cotton fiber quality

Cotton fiber is a commodity of key economic importance in both developed and developing countries. The two cultivated species, Gossypium hirsutum and G. barbadense , are tetraploid (2n=1x= 52 . 2.3 Gb). Cotton fibers are single-celled trichomes of the outermost epidermallayer of the ovule and elongate extensively to 25-50 mm. The final quality of the fiber results from complex developmentai processes and improvement of cotton fiber quality remains a challenge for many research groups worldwide. Although traditional breeding methods have proven efficient, the contribution of molecular genetics and genomic tools are gaining interest and the cotton fiber transcriptome has attracted a lot of attention in recent years. The major objective of the project (acronym Cotton_RILs) sponsored by the French National Research Agency (ANR) , is the genetic and genomic dissection of important fiber quality characteristics using a combination of classical QTL mapping and of gene expression QTL mapping. The integrated genetics and genomics approach (or genetical genomics approach) in this project is centered on a population of interspecific G. hirsutum X G. harhadense recombinant inbred lines (RILs) created by CIRAD. Specifie objectives are, 1. Construction of a saturated genetic map, 2. QTL mapping through multi-site phenotypic evaluation on 1 continents. 3. Population-wide gene expression analysis through microarray and cDNA-AFLP profilings and for 1 or 2 key developmental stages, and 4. Genetic fine mapping of selected QTLs using a large F, population. The 3 participants in the project. CIRAD (Montpellier, France) . Bayer Crop Science (Gent . Belgium). and CSIRü (Canberra , Australia) , have active research programs in applied genetics both through c1assical breeding and using modern biotechnology. Past achievements of the 3 laboratories are recognized worldwide and they are highly complementary in terms of their scientific expertise. Apart from greenhouses and biotechnology laboratories in their respective primary sites, they provide access to a broad range of field experimental sites on 4 continents, in Brazil and Cameroon through CIRAD partnerships and in the USA for Bayer CS. (Texte intégral

Access regulation and the transition from copper to fiber networks in telecoms

In this paper we study the impact of different forms of access obligations on firms' incentives to migrate from the legacy copper network to ultra-fast broadband infrastructures. We analyze three different kinds of regulatory interventions: geographical regulation of access to copper networks-where access prices are differentiated depending on whether or not an alternative fiber network has been deployed; access obligations on fiber networks and its interplay with wholesale copper prices; and, finally, a mandatory switch-off of the legacy copper network-to foster the transition to the higher quality fiber networks. Trading-off the different static and dynamic goals, the paper provides guidelines and suggestions for policy makers' decision

Major results and research challenges in cotton molecular genetics at Cirad (France)

CIRAD (Montpellier, France) develops research activities centered on tropical and sub-tropical agricultural systems. Among others crops, cotton is the fucus of a series of research programs in different disciplines from economics to breeding. Major areas in genetics and breeding relate to (1) genetic diversity, (2) cultivar development through classical and molecular breeding, and (3) applied genomics. An important but under-exploited reservoir of genetic diversity exists within the genus Gossypium. With over 3000 accessions CIRAD has one of the few important gene banks worldwide. It includes cultivars, landraces , and wild Gossypiurn species. DNA molecular markeTs have shawn their usefulness and validity for fingerprinting plant resources and for structuring diversity of large collections. In our case, after a preliminary step centered on the screening of microsatellite markers over a limited set of accessions of the gene bank (a genotyping kit has been proposed) , our future plans include the use of high-throughput methods of genotyping (a DArT platform will soon be available in our unit). Opportunities for exploiting this large diversity relate to the development core-collections and of genetic association studies for a given set of traits (fiber quality, stress response) . After a past and fruitful period of collaboration in different tropical countries (varieties co-obtained by ClRAD are cultivated on over 2. 5 million hectares worldwide), CIRAD has more recently engaged research programs in molecular genetics. Focus has initially been on fiber quality as a target trait and on markerassisted interspecific breeding for introgressing fiber quality traits from G. barbadense into G. hirsutUtn. Achievements in this area (genetic maps, fiber quality QTLs) have been published and are posted on the web. The database of CIRAD, TropGene DB (available at http, lltropgenedb. cirad. h l ) is regularly updated and presently displays various genetic maps as well as QTL data. Based upon QTL detected in the BCI and BC2 (backcross to the Gh parent) generations, marker-assisted selection in further generations (BC3 to BCG) was conducted and advanced lines introgressed with 3 ~ 5 QTLs were tested under tropical conditions. Using the same material, libraries of segmental introgression lines are being created for a few specifie target chromosomes. More recently , through collaboration with Embrapa (Brazil), CIRAD has initiated research on disease and nematode resistances in order to clarify the genetic basis of resistance; prepare segregating populations, and develop marker-assisted selection programs. A new collaborative project coordinated by CIRAD on the genetics and genomics of cotton fiber quality has been launched in 2007. CIRAD and its partners, Bayer CS and CSIRü, are engaged in ambitious research aimed at elucidating the genetic basis of fiber quality. The project is centered on an interspecific RIL population (a cross between 2 weil studied parents , Guazuncho 2 (G. hirsuturn) and VH8 (G. harhadense)) . It is innovative by the approach combining (1) phenotypic assessment of fi ber quality from field and greenhouse experiments on four continents, and (2) transcriptome profiling using complementary platforms, hybridization-based (microarrays) and PCR-based (cDNA-AFLP). Comparison of QTL and eQTL results is expected to help in identifying candidate genes important in fiber quality. (Résumé d'auteur