703 research outputs found
Utilisation des mutations induites pour l'étude de l'embryogenèse chez le haricot Phaseolus vulgaris L. et deux plantes modèles Arabidopsis thaliana (L.) Heynh. et Zea mays L.
Use of induced mutations in embryogenesis study in bean Phaseolus vulgaris L. and two model plants, Arabidopsis thaliana (L.) Heynh. and Zea mays L.. Breeding of common bean, Phaseolus vulgaris L., through interspecific hybridizations with the species Phaseolus coccineus L. and Phaseolus polyanthus Greenm. as female parents leads to the abortion of immature embryos. Identification of genes required for embryo development could partly explain the abortion of hybrid embryos; induced mutations could thus be an alternative to identify key genes involved in Phaseolus embryogenesis. This paper is a review which shows a few examples of the use of induced mutations in the identification of essential genes for embryogenesis in two model plants, Arabidopsis thaliana (L.) Heyhn. for dicots and Zea mays L. for monocots. In these two species, embryo development mutants have been isolated using insertional mutagenesis and chemical mutagenesis with Ethyl Methane Sulfonate (EMS). Arabidopsis embryo mutants are affected in apical-basal axis polarity, radial pattern and in post-embryonic stages. Some Arabidopsis embryo mutants are defected in auxin signalisation. In maize, defective kernel (dek) mutants are affected in the embryo and the endosperm, while in embryo specific (emb) mutants, only the embryo is affected. In common bean, plants deficient in seed development were isolated using EMS mutagenesis. Embryos inside the seeds fail to growth at different stages of development and show abnormalities mainly in the suspensor and the cotyledons
Envelope Factorization with Partial Elimination and Recombination, EF-PER, a New Linear RF Architecture
In this paper, a new architecture for efficient linear radio frequency transmitters is proposed; it includes envelope-tracking (ET) and envelope-elimination-and-restoration (EER) architectures as special instances. The proposed technique is referred to as Envelope Factorization with Partial Elimination and Recombination (EF-PER). It relies on a decomposition of the RF signal before power amplification as a product of two signals, one of them being the envelope signal elevated to an exponent “α”. Compared to ET or EER architectures, the parameter “α” constitutes a new degree of freedom. This allows one to realize good tradeoffs between different performance criteria such as spectrum use, power efficiency, and transmitter linearity. An intuitive aggregate cost function is introduced to capture the desired tradeoff and turns out to be maximized in α=0.5. The full relevance of EF-PER is sustained both by analytical results and realistic simulations performed for OFDM signals. The EF-PER architecture (with α=0.5) has been simulated under Agilent-ADS with a non-linear transistor model from Avago (E-PHEMT) and compared with ET and EER
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Les hybridations interspecifiques dans le genre Phaseolus : selection des genotypes compatibles et caracterisation des hybrides interspecifiques
La réussite de l’introgression de caractères utiles chez le haricot commun P. vulgaris à partir des deux espèces P. coccineus et P. polyanthus dépend en partie des génotypes utilisés. Ce travail vise à identifier des génotypes de Phaseolus compatibles lors des hybridations interspécifiques et à identifier les hybrides issus des croisements entre P. vulgaris utilisé comme parent mâle et les deux autres espèces utilisées comme parents femelles. Dans les croisements P. coccineus x P. vulgaris, le taux de gousses avortées audelà  de 8 JAP est d’environ 12 %. Quatre gousses supposées hybrides ont été obtenues. Pour les hybridations P. polyanthus x P. vulgaris, le taux de gousses avortés au-delà de 8 JAP est d’environ 18 % et une seule gousse supposée hybride a été produite. Les hybrides issus des deux combinaisons interspécifiques ont été mis en évidence au moyen de caractères morphologiques et grâce à un marqueur moléculaire microsatellite. Les génotypes retenus pour leur bonne aptitude à la combinaison, en tenant compte des taux d’avortement au-delà de 8 JAP, sont les suivants : NI637 et G21245 pour P. vulgaris, NI889 et NI16 pour P. coccineus, NI1015 et G35348 pour P. polyanthus. Mots clés : Phaseolus, hybridations interspécifiques, caractères morphologiques, marqueur microsatellite (SSR).INTERSPECIFIC HYBRIDIZATIONSWITHIN THE GENUS PhaseolusSuccessful introgression of useful traits in common bean P. vulgaris from the two species P. coccineus and P. polyanthus depends in part to genotypes used. This work aims to identify genotypes of Phaseolus compatible during interspecific crosses and to identify hybrids from crosses between P. vulgaris used as male parent and the other two species used as female parents. In crosses P. coccineus x P. vulgaris, the rate of pod abortion 8 days after pollination (DAP) is around 12 %. Four putative hybrid pods were obtained. For hybridizations P. polyanthus x P. vulgaris, the rate of pod abortion 8 DAP is around 18 % and one putative hybrid pod was produced. The hybrid nature of one plant from each interspecific combination was confirmed using morphological characters and one microsatellite molecular marker. Genotypes selected for good combining abilities, considering pod abortion rates 8 DAP are NI637 and G21245 for P. vulgaris, NI889 and NI16 for P. coccineus, NI1015 and G35348 for P. polyanthus.Keywords : Phaseolus, interspecific hybridizations, morphological characters, microsatellite marker (SSR)
Stochastic B\"acklund transformations
How does one introduce randomness into a classical dynamical system in order
to produce something which is related to the `corresponding' quantum system? We
consider this question from a probabilistic point of view, in the context of
some integrable Hamiltonian systems
Análisis de linajes maternos y paternos de bovinos criollo del Centro de EcologĂa Aaplicada SimĂłn I. Patiño - Bolivia
Se determinaron los linajes maternos y paternos de 33 bovinos Criollo (27 hembras y 6 machos) del Centro de EcologĂa Aplicada SimĂłn I. Patiño (Ceasip) mediante marcadores genĂ©ticos del ADN genĂłmico, mitocondrial y del cromosoma Y. El ADN genĂłmico se extrajo utilizando el kit Wizard ® Genomic Purification. Los linajes maternos se determinaron mediante secuenciaciĂłn del ADN mitocondrial (regiĂłn control D-loop) y los linajes paternos se determinaron analizando siete marcadores genĂ©ticos del cromosoma Y, dos SNP (Polimorfismo de NucleĂłtido Simple) y cinco microsatĂ©lites (Secuencias Repetidas en Tándem). La diversidad genĂ©tica se estimĂł tipificando 18 microsatĂ©lites. Se analizaron los datos con MStools, GenePop y Arlequin. La secuenciaciĂłn de D-loop mitocondrial permitiĂł detectar seis linajes maternos, que incluĂan cuatro haplotipos mitocondriales de origen europeo y dos africanos. A travĂ©s del análisis de los marcadores del cromosoma Y se determinaron tres linajes paternos, dos taurinos y uno cebuino. En el hato del Ceasip, la diversidad alĂ©lica (na) fue de 6.11, mientras que la heterocigosidad esperada (He) fue de 0.70 y la observada (Ho) fue de 0.68. Los valores de diversidad genĂ©tica observada en los bovinos del Ceasip son similares a los estimados para la mayorĂa de los biotipos del Criollo boliviano (na Yacumeño= 6.82; na Saavedreño= 5.95), siendo los valores promedios para el ganado Criollo boliviano analizados anteriormente de na= 6.39, He= 0.72 y Ho= 0.65. Los análisis de Componentes Principales y de distancia genĂ©tica mostraron que serĂa factible intercambiar material genĂ©tico entre las poblaciones Criollo bolivianas sin pĂ©rdida significativa de su diversidad genĂ©tica.Fil: Pereira, J. A. C.. Universidad AutĂłnoma Gabriel RenĂ© Moreno; BoliviaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Peña, S.. Centro de EcologĂa Aplicada SimĂłn I. Patiño; BoliviaFil: Liron, Juan Pedro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico La Plata. Instituto de GenĂ©tica Veterinaria ; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Loza, A. J.. Universidad AutĂłnoma Gabriel RenĂ© Moreno; BoliviaFil: Posik, Diego Manuel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico La Plata. Instituto de GenĂ©tica Veterinaria ; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Baudoin, M.. Centro de EcologĂa Aplicada SimĂłn I. Patiño; BoliviaFil: Bomblat, C.. Centro de EcologĂa Aplicada SimĂłn I. Patiño; Bolivi
System of Complex Brownian Motions Associated with the O'Connell Process
The O'Connell process is a softened version (a geometric lifting with a
parameter ) of the noncolliding Brownian motion such that neighboring
particles can change the order of positions in one dimension within the
characteristic length . This process is not determinantal. Under a special
entrance law, however, Borodin and Corwin gave a Fredholm determinant
expression for the expectation of an observable, which is a softening of an
indicator of a particle position. We rewrite their integral kernel to a form
similar to the correlation kernels of determinantal processes and show, if the
number of particles is , the rank of the matrix of the Fredholm determinant
is . Then we give a representation for the quantity by using an -particle
system of complex Brownian motions (CBMs). The complex function, which gives
the determinantal expression to the weight of CBM paths, is not entire, but in
the combinatorial limit it becomes an entire function providing
conformal martingales and the CBM representation for the noncolliding Brownian
motion is recovered.Comment: v3: AMS_LaTeX, 25 pages, no figure, minor corrections made for
publication in J. Stat. Phy
Fabrication and Electro-optic Properties of MWCNT Driven Novel Electroluminescent Lamp
We present a novel, cost-effective and facile technique, wherein multi-walled
carbon nano-tubes (CNTs) were used to transform a photoluminescent material to
exhibit stable and efficient electroluminescence (EL) at low-voltages. As a
case study, a commercially available ZnS:Cu phosphor (P-22G) was combined with
a very low concentration of CNTs dispersed in ethanol and its alternating
current driven electroluminescence (AC-EL) is demonstrated. The role of CNTs
has been understood as a local electric field enhancer and facilitator in the
hot carrier injection inside the ZnS crystal to produce EL in the hybrid
material. The mechanism of EL is discussed using an internal field emission
model, intra-CNT impact excitation and the recombination of electrons and holes
through the impurity states.Comment: 9 Figure
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