64 research outputs found
Probing eigenfunction nonorthogonality by parametric shifts of resonance widths
Recently, it has been shown that the change of resonance widths in an open system under a perturbation of its interior is a sensitive indicator of the nonorthogonality of resonance states. We apply this measure to quantify parametric motion of the resonances. In particular, a strong redistribution of the widths is linked with the maximal degree of nonorthogonality. Then for weakly open chaotic systems we discuss the effect of spectral rigidity on the statistical properties of the parametric width shifts, and derive the distribution of the latter in a picket-fence model with equidistant spectrum
Similar glassy features in the NMR response of pure and disordered La1.88Sr0.12CuO4
High Tc superconductivity in La2-xSrxCuO4 coexists with (striped and glassy)
magnetic order. Here, we report NMR measurements of the 139La spin-lattice
relaxation, which displays a stretched-exponential time dependence, in both
pure and disordered x=0.12 single crystals. An analysis in terms of a
distribution of relaxation rates T1^-1 indicates that i) the spin-freezing
temperature is spatially inhomogeneous with an onset at Tg(onset)=20 K for the
pristine samples, and ii) the width of the T1^-1 distribution in the vicinity
of Tg(onset) is insensitive to an ~1% level of atomic disorder in CuO2 planes.
This suggests that the stretched-exponential 139La relaxation, considered as a
manifestation of the systems glassiness, may not arise from quenched disorder.Comment: 7 pages, to be published in Phys. Rev.
Preempted phonon-mediated superconductivity in the infinite-layer nickelates
Nickelate superconductors are outstanding materials with intriguing analogies
with the cuprates. These analogies suggest that their superconducting mechanism
is similarly unconventional, although this fundamental question is currently
under debate. Here, we scrutinize the role played by electronic correlations in
enhancing the electron-phonon coupling in the infinite-layer nickelates and the
extent to which this may promote superconductivity. Specifically, we use
many-body perturbation theory to perform state-of-the-art and
Eliashberg-theory calculations. We find that the electron-phonon coupling is in
effect enhanced compared to density-functional-theory calculations. This
enhancement may lead to low- superconductivity in the parent compounds
already. However, it remains marginal in the sense that it cannot explain the
record s obtained with doping. Conventional superconductivity then appears
to be preempted by another mechanism in the infinite-layer nickelates.Comment: 6 pages, 4 figures, 1 table + Supplementary Informatio
Large enhancement of the thermopower in NaCoO at high Na doping
Research on the oxide perovskites has uncovered electronic properties that
are strikingly enhanced compared with those in conventional metals. Examples
are the high critical temperatures of the cuprate superconductors and the
colossal magnetoresistance in the manganites. The conducting layered cobaltate
displays several interesting electronic phases as is varied
including water-induced superconductivity and an insulating state that is
destroyed by field. Initial measurements showed that, in the as-grown
composition, displays moderately large thermopower and
conductivity . However, the prospects for thermoelectric cooling
applications faded when the figure of merit was found to be small at this
composition (0.60.7). Here we report that, in the poorly-explored
high-doping region 0.75, undergoes an even steeper enhancement. At the
critical doping 0.85, (at 80 K) reaches values 40 times
larger than in the as-grown crystals. We discuss prospects for low-temperature
thermoelectric applications.Comment: 6 pages, 7 figure
DETERMINATION OF TYPES OF INDIVIDUALS IN APHIDS, ROTIFERS AND CLADOCERA 1
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72827/1/j.1469-185X.1929.tb00888.x.pd
Realtime Cardiac Arrhythmias Monitoring for Pervasive Healthcare
International audienc
A Real-Time Continuous Cardiac Arrhythmias Detection System: RECAD
International audienc
Haplodiploidization of maize (Zea mays L) through induced gynogenesis assisted by glossy markers and its use in breeding
Reliable detection of haploids at the seedling stage is a prerequisite for the use of haplodiploidization through in situ gynogenesis in maize breeding. The use of recessive alleles of glossy genes as markers makes this detection possible in various materials. Two synthetics with a wide genetic basis: flint glossy1 CGT and dent glossy6 DGT were studied. After pollination with the FIGH 1 inducer, they produced haploid seedlings at a rate of 0.64 and 0.93%, respectively. The rate is increased (0.94% on average) for the CGT (C 0) synthetic after selfing, in S1 progenies. The distribution of 203 S1 families showed a significant deviation in comparison with a Poisson distribution. The DGT synthetic showed an increase in induction rate when a new synthetic was formed with doubled haploid (DH) lines, suggesting that 'inductibility' may have some genetic effects. No spontaneous doubling was shown by the haploid seedlings of either synthetic. Colchicine treatment allowed a recovery of male fertility in 30 to 60% of detected haploids according to the experiments. The progeny recovery rate was influenced by the genetic basis, as the DGT synthetic gave better results than the CGT synthetic. The growing period also had an influence upon the recovery of fertile ears. Hybrids produced from heterotic DH lines showed an agronomic potential similar to standard hybrids. It is concluded that in situ gynogenesis assisted by the use of glossy markers can now be used in maize breeding.Haplodiploïdisation du maïs (Zea mays L) par gynogenèse induite assistée par marqueurs glossy et son application en sélection. L'utilisation effective de l'haplodiploïdisation par gynogenèse in situ en sélection du maïs nécessite une détection fiable des haploïdes au stade plantule. Le marquage génotypique par des allèles récessifs des gènes glossy permet cette détection. Deux «synthétiques» à base large: CGT (cornée glossyl tardive), DGT (dentée glossy6 tardive), ont été étudiées. Pollinisées par l'inducteur FIGH 1, elles ont produit des plantes haploïdes à des taux respectifs de : 0,64 et 0,93 %. Pour la synthétique CGT (C0), ce taux est augmenté (0,94 % en moyenne) lorsque l'on passe de la première génération aux descendances S1. L'analyse de la distribution de l'induction de 203 S1 de CGT montre une déviation significative par rapport à une distribution de Poisson. Dans la population DGT, le taux d'induction de plantes haploïdes s'est accru par la constitution d'une «synthétique» à partir de lignées haploïdes doublées (HD). Cela suggère des effets génétiques pour «l'inductibilité». Les plantules haploïdes provenant de CGT et DGT n'ont pas présenté de diploïdisation spontanée. Le traitement à la colchicine permet la restauration de la fertilité mâle dans 30 à 60 % des cas selon les essais. Le taux de descendances diploïdes fertiles obtenues par rapport au nombre d'haploïdes traités varie en fonction du matériel génétique (DGT est supérieure à CGT) et des périodes de culture des plantes traitées colchicine. Des hybrides réalisés à partir de lignées HD complémentaires possèdent un potentiel agronomique intéressant, parfois proche des témoins. La gynogenèse in situ assistée par marqueurs glossy est envisageable en sélection
Haplodiploidization of maize (Zea mays L) through induced gynogenesis assisted by glossy markers and its use in breeding
Reliable detection of haploids at the seedling stage is a prerequisite for the use of haplodiploidization through in situ gynogenesis in maize breeding. The use of recessive alleles of glossy genes as markers makes this detection possible in various materials. Two synthetics with a wide genetic basis: flint glossy1 CGT and dent glossy6 DGT were studied. After pollination with the FIGH 1 inducer, they produced haploid seedlings at a rate of 0.64 and 0.93%, respectively. The rate is increased (0.94% on average) for the CGT (C 0) synthetic after selfing, in S1 progenies. The distribution of 203 S1 families showed a significant deviation in comparison with a Poisson distribution. The DGT synthetic showed an increase in induction rate when a new synthetic was formed with doubled haploid (DH) lines, suggesting that 'inductibility' may have some genetic effects. No spontaneous doubling was shown by the haploid seedlings of either synthetic. Colchicine treatment allowed a recovery of male fertility in 30 to 60% of detected haploids according to the experiments. The progeny recovery rate was influenced by the genetic basis, as the DGT synthetic gave better results than the CGT synthetic. The growing period also had an influence upon the recovery of fertile ears. Hybrids produced from heterotic DH lines showed an agronomic potential similar to standard hybrids. It is concluded that in situ gynogenesis assisted by the use of glossy markers can now be used in maize breeding.Haplodiploïdisation du maïs (Zea mays L) par gynogenèse induite assistée par marqueurs glossy et son application en sélection. L'utilisation effective de l'haplodiploïdisation par gynogenèse in situ en sélection du maïs nécessite une détection fiable des haploïdes au stade plantule. Le marquage génotypique par des allèles récessifs des gènes glossy permet cette détection. Deux «synthétiques» à base large: CGT (cornée glossyl tardive), DGT (dentée glossy6 tardive), ont été étudiées. Pollinisées par l'inducteur FIGH 1, elles ont produit des plantes haploïdes à des taux respectifs de : 0,64 et 0,93 %. Pour la synthétique CGT (C0), ce taux est augmenté (0,94 % en moyenne) lorsque l'on passe de la première génération aux descendances S1. L'analyse de la distribution de l'induction de 203 S1 de CGT montre une déviation significative par rapport à une distribution de Poisson. Dans la population DGT, le taux d'induction de plantes haploïdes s'est accru par la constitution d'une «synthétique» à partir de lignées haploïdes doublées (HD). Cela suggère des effets génétiques pour «l'inductibilité». Les plantules haploïdes provenant de CGT et DGT n'ont pas présenté de diploïdisation spontanée. Le traitement à la colchicine permet la restauration de la fertilité mâle dans 30 à 60 % des cas selon les essais. Le taux de descendances diploïdes fertiles obtenues par rapport au nombre d'haploïdes traités varie en fonction du matériel génétique (DGT est supérieure à CGT) et des périodes de culture des plantes traitées colchicine. Des hybrides réalisés à partir de lignées HD complémentaires possèdent un potentiel agronomique intéressant, parfois proche des témoins. La gynogenèse in situ assistée par marqueurs glossy est envisageable en sélection
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