1,269 research outputs found

    Parity-violating asymmetry in γdnp\gamma d \to \vec{n}p with a pionless effective theory

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    Nuclear parity violation is studied with polarized neutrons in the photodisintegration of the deuteron at low energies. A pionless effective field theory with di-baryon fields is used for the investigation. Hadronic weak interactions are treated by parity-violating di-baryon-nucleon-nucleon vertices, which have undetermined coupling contants. A parity-violating asymmetry in the process is calculated for the incident photon energy up to 30 MeV. If experimental data for the parity-violating asymmetry become available in the future, we will be able to determine the unknown coupling contants in the parity-violating vertices.Comment: 4 pages. A contribution to APFB2011, August 22-26, 2011, Seoul, Kore

    A role for SUMO modification in transcriptional repression and activation

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    Since the discovery of the SUMO (small ubiquitin-like modifier) family of proteins just over a decade ago, a plethora of substrates have been uncovered including many regulators of transcription. Conjugation of SUMO to target proteins has generally been considered as a repressive modification. However, there are now a growing number of examples where sumoylation has been shown to activate transcription. Here we discuss whether there is something intrinsically repressive about sumoylation, or if the outcome of this modification in the context of transcription will prove to be largely substrate-dependent. We highlight some of the technical challenges that will be faced by attempting to answer this question

    Projected SO(5) Hamiltonian for Cuprates and Its Applications

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    The projected SO(5) (pSO(5)) Hamiltonian incorporates the quantum spin and superconducting fluctuations of underdoped cuprates in terms of four bosons moving on a coarse grained lattice. A simple mean field approximation can explain some key feautures of the experimental phase diagram: (i) The Mott transition between antiferromagnet and superconductor, (ii) The increase of T_c and superfluid stiffness with hole concentration x and (iii) The increase of antiferromagnetic resonance energy as sqrt{x-x_c} in the superconducting phase. We apply this theory to explain the ``two gaps'' problem found in underdoped cuprate Superconductor-Normal- Superconductor junctions. In particular we explain the sharp subgap Andreev peaks of the differential resistance, as signatures of the antiferromagnetic resonance (the magnon mass gap). A critical test of this theory is proposed. The tunneling charge, as measured by shot noise, should change by increments of Delta Q= 2e at the Andreev peaks, rather than by Delta Q=e as in conventional superconductors.Comment: 3 EPS figure

    The complete chloroplast genome of pearl millet (Pennisetum glaucum (L.) R. Br.) and comparative analysis within the family poaceae

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    The complete chloroplast (cp) genome sequence of Pearl millet (Pennisetum glaucum [L.] R. Br.), an important grain and forage crop in the family Poaceae, is reported in this study. The complete cp genome sequence of P. glaucum is 138,172 bp in length with 38.6% overall GC content and exhibits a typical quadripartite structure comprising one pair of inverted repeat (IR) regions (22,275 bp) separated by a small single-copy (SSC) region (12,409 bp) and a large single-copy (LSC) region (81,213). The P. glaucum cp genome encodes 110 unique genes, 76 of which are protein-coding genes, 4 ribosomal RNA (rRNA) genes, 30 transfer RNA (tRNA) genes and 18 duplicated genes in the IR region. Nine genes contain one or two introns. Whole genome alignments of cp genome were performed for genome-wide comparison. Locally collinear blocks (LCBs) identified among the cp genomes showed that they were well conserved with respect to gene organization and order. This newly determined cp genome sequence of P. glaucum will provide valuable information for the future breeding programs of valuable cereal crops in the family Poaceae

    Phylogeny and taxonomy of obscure genera of microfungi

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    The recently generated molecular phylogeny for the kingdom Fungi, on which a new classification scheme is based, still suffers from an under representation of numerous apparently asexual genera of microfungi. In an attempt to populate the Fungal Tree of Life, fresh samples of 10 obscure genera of hyphomycetes were collected. These fungi were subsequently established in culture, and subjected to DNA sequence analysis of the ITS and LSU nrRNA genes to resolve species and generic questions related to these obscure genera. Brycekendrickomyces (Herpotrichiellaceae) is introduced as a new genus similar to, but distinct from Haplographium and Lauriomyces. Chalastospora is shown to be a genus in the Pleosporales, with two new species, C. ellipsoidea and C. obclavata, to which Alternaria malorum is added as an additional taxon under its oldest epithet, C. gossypii. Cyphellophora eugeniae is newly described in Cyphellophora (Herpotrichiellaceae), and distinguished from other taxa in the genus. Dictyosporium is placed in the Pleosporales, with one new species, D. streliziae. The genus Edenia, which was recently introduced for a sterile endophytic fungus isolated in Mexico, is shown to be a hyphomycete (Pleosporales) forming a pyronellea-like synanamorph in culture. Thedgonia is shown not to represent an anamorph of Mycosphaerella, but to belong to the Helotiales. Trochophora, however, clustered basal to the Pseudocercospora complex in the Mycosphaerellaceae, as did Verrucisporota. Vonarxia, a rather forgotten genus of hyphomycetes, is shown to belong to the Herpotrichiellaceae and Xenostigmina is confirmed as synanamorph of Mycopappus, and is shown to be allied to Seifertia in the Pleosporales. Dichotomous keys are provided for species in the various genera treated. Furthermore, several families are shown to be polyphyletic within some orders, especially in the Capnodiales, Chaetothyriales and Pleosporales

    Parity-violating neutron spin rotation in hydrogen and deuterium

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    We calculate the (parity-violating) spin rotation angle of a polarized neutron beam through hydrogen and deuterium targets, using pionless effective field theory up to next-to-leading order. Our result is part of a program to obtain the five leading independent low-energy parameters that characterize hadronic parity-violation from few-body observables in one systematic and consistent framework. The two spin-rotation angles provide independent constraints on these parameters. Using naive dimensional analysis to estimate the typical size of the couplings, we expect the signal for standard target densities to be 10^-7 to 10^-6 rad/m for both hydrogen and deuterium targets. We find no indication that the nd observable is enhanced compared to the np one. All results are properly renormalized. An estimate of the numerical and systematic uncertainties of our calculations indicates excellent convergence. An appendix contains the relevant partial-wave projectors of the three-nucleon system.Comment: 44 pages, 17 figures; minor corrections; to be published in EPJ

    Towards T1-limited magnetic resonance imaging using Rabi beats

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    Two proof-of-principle experiments towards T1-limited magnetic resonance imaging with NV centers in diamond are demonstrated. First, a large number of Rabi oscillations is measured and it is demonstrated that the hyperfine interaction due to the NV's 14N can be extracted from the beating oscillations. Second, the Rabi beats under V-type microwave excitation of the three hyperfine manifolds is studied experimentally and described theoretically.Comment: 6 pages, 8 figure

    Parity nonconservation in deuteron photoreactions

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    We calculate the asymmetries in parity nonconserving deuteron photodisintegration due to circularly polarized photons gamma+d to n+p with the photon laboratory energy ranging from the threshold up to 10 MeV and the radiative capture of thermal polarized neutrons by protons n+p to gamma+d. We use the leading order electromagnetic Hamiltonian neglecting the smaller nuclear exchange currents. Comparative calculations are done by using the Reid93 and Argonne v18 potentials for the strong interaction and the DDH and FCDH "best" values for the weak couplings in a weak one-meson exchange potential. A weak NDelta transition potential is used to incorporate also the Delta(1232)-isobar excitation in the coupled-channels formalism.Comment: 14 pages, 13 figures (18 eps files), LaTeX2

    Effects of diet composition on growth performance and feed conversion efficiency in Alphitobius diaperinus larvae

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    Alphitobius diap]erinus has been recommended for mass-production as feed in a rearing facility because of its small size and short biological cycle. This study evaluated the effects of wheat bran and casein or their blend as insect diets on growth performance and feed conversion efficiency of A. diaperinus larvae in the laboratory. Casein and wheat bran were the protein and carbohydrate sources of choice, respectively, for diet preparation. Five experimental diet treatments to be tested were designed as follows: control (100% casein), T1 (75% casein +25% wheat bran), T2 (50% casein +50% wheat bran), T3 (25% casein +70% wheat bran), and T4 (100% wheat bran). A total of 150 new hatched larvae were randomly allotted to one of the five dietary treatments, with three replicates (10 hatched larvae per replicate). The standard colonies were composed of 10 hatched larvae, without distinction of sex, reared in a plastic box (14×8×5 cm) provided with aeration holes on the top. The evaluation of A. diaperinus larvae included growth performance and feed efficiency. Using casein and wheat bran blends for diet had a positive effect on weight gain and feed conversion ratio of A. diaperinus larvae, including an increase in average larval survival and average larval weight. Using casein and wheat blends (75% casein +25% wheat bran or 25% casein +70% wheat bran) as insect-rearing diet will allow effective utilization of the feed for poultry when using the edible portion of mealworms before reaching the pupae stage

    p-wave phase shift and scattering length of 6^6Li

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    We have calculated the p-wave phase shifts and scattering length of 6^6Li. For this we solve the pp partial wave Schr\"odinger equation and analyze the validity of adopting the semiclassical solution to evaluate the constant factors in the solution. Unlike in the ss wave case, the semiclassical solution does not provide unique value of the constants. We suggest an approximate analytic solution, which provides reliable results in special cases. Further more, we also use the variable phase method to evaluate the phase shifts. The p-wave scattering lengths of 132^{132}Cs and 134^{134}Cs are calculated to validate the schemes followed. Based on our calculations, the value of the pp wave scattering length of 6^6Li is 45ao-45a_o.Comment: 10 figure
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