Evolution of the superposition of displaced number states with the two-atom multiphoton Jaynes-Cummings model: interference and entanglement

In this paper we study the evolution of the two two-level atoms interacting with a single-mode quantized radiation field, namely, two-atom multiphoton Jaynes-Cummings model when the radiation field and atoms are initially prepared in the superpostion of displaced number states and excited atomic states, respectively. For this system we investigate the atomic inversion, Wigner function, phase distribution and entanglement.Comment: 18 pages, 17 figure

Genetic variation, population structure and linkage disequilibrium in peach commercial varieties

11 páginas, 5 figuras, 2 tablas.[Background]: Peach [Prunus persica (L.) Batsch] is one of the most economically important fruit crops that, due to its genetic and biological characteristics (small genome size, taxonomic proximity to other important species and short juvenile period), has become a model plant in genomic studies of fruit trees. Our aim was an in-depth study of the extent, distribution and structure of peach genetic variation in North American and European commercial varieties as well as old Spanish varieties and several founders used in the early USA peach breeding programmes. For this we genotyped 224 peach cultivars using 50 SSRs evenly distributed along the 8 linkage groups of the Prunus reference map. [Results]: Genetic distance analysis based on SSRs divided the peach cultivars in three main groups based mainly on their fruit characteristics: melting flesh peaches, melting flesh nectarines and non-melting varieties. Whereas non-melting flesh peaches had a higher number of alleles than melting peaches and nectarines, they were more homozygous. With some exceptions ('Admiral Dewey', 'Early Crawford' and 'Chinese Cling'), the founder US cultivars clustered together with the commercial melting peaches, indicating that their germplasm is well represented in modern cultivars. Population structure analysis showed a similar subdivision of the sample into subpopulations. Linkage disequilibrium (LD) analysis in three unstructured, or barely structured, subpopulations revealed a high level of LD conservation in peach extending up to 13-15 cM. [Conclusions]: Using a much larger set of SSRs, our results confirm previous observations on peach variability and population structure and provide additional tools for breeding and breeders' rights enforcement. SSR data are also used for the estimation of marker mutation rates and allow pedigree inferences, particularly with founder genotypes of the currently grown cultivars, which are useful to understand the evolution of peach as a crop. Results on LD conservation can be explained by the self-pollinating nature of peach cultivated germplasm and by a bottleneck that occurred at the beginning of modern breeding practices. High LD suggests that the development of whole-genome scanning approaches is suitable for genetic studies of agronomically important traits in peach.This research was funded in part by Project AGL2006-07767/AGR and by the Consolider-Ingenio 2010 Program (CSD2007-00036), both from the Spanish Ministry of Science and Innovation.Peer reviewe

The photospheres of the hottest fastest stars in the Galaxy

We perform nonlocal thermodynamic equilibrium (NLTE) model atmosphere analyses of the three hottest hypervelocity stars (space velocities between $\approx$ 1500-2800 km s$^{-1}$) known to date, which were recently discovered spectroscopically and identified as runaways from Type Ia supernovae. The hottest of the three (J0546$+$0836, effective temperature $T_\mathrm{eff}$ = 95,000 $\pm$ 15,000 K, surface gravity log g = $5.5 \pm 0.5$) has an oxygen-dominated atmosphere with a significant amount of carbon (C = $0.10 \pm 0.05$, O = $0.90 \pm 0.05$, mass fractions). Its mixed absorption+emission line spectrum exhibits photospheric absorption lines from O V and O VI as well as O III and O IV emission lines that are formed in a radiation-driven wind with a mass-loss rate of the order of $10^{-8}$ $M_\odot$ yr$^{-1}$. Spectroscopically, J0546$+$0836 is a [WC]-PG1159 transition-type pre-white dwarf. The second object (J0927$-$6335) is a PG1159-type white dwarf with a pure absorption-line spectrum dominated by C III/C IV and O III/O IV. We find $T_\mathrm{eff}$ = 60,000 $\pm$ 5000 K, log g = $7.0 \pm 0.5$, and a carbon- and oxygen-dominated atmosphere with C = $0.47 \pm 0.25$, O = $0.48 \pm 0.25$, and possibly a minute amount of helium (He = $0.05 \pm 0.05$). Comparison with post-AGB evolutionary tracks suggests a mass of $M\approx0.5$ $M_\odot$ for both objects, if such tracks can safely be applied to these stars. We find the third object (J1332$-$3541) to be a relatively massive ($M=0.89 M_\odot$) hydrogen-rich (DAO) white dwarf with $T_\mathrm{eff}$ = 65,657 $\pm$ 2390 K, log g = $8.38 \pm 0.08$, and abundances H = $0.65 \pm 0.04$ and He = $0.35 \pm 0.04$. We discuss our results in the context of the "dynamically driven double-degenerate double-detonation" (D$^6$) scenario proposed for the origin of these stars.Comment: Accepted for publication in A&

Correlating novel variable and conserved motifs in the Hemagglutinin protein with significant biological functions

<p>Abstract</p> <p>Background</p> <p>Variations in the influenza Hemagglutinin protein contributes to antigenic drift resulting in decreased efficiency of seasonal influenza vaccines and escape from host immune response. We performed an in silico study to determine characteristics of novel variable and conserved motifs in the Hemagglutinin protein from previously reported H3N2 strains isolated from Hong Kong from 1968–1999 to predict viral motifs involved in significant biological functions.</p> <p>Results</p> <p>14 MEME blocks were generated and comparative analysis of the MEME blocks identified blocks 1, 2, 3 and 7 to correlate with several biological functions. Analysis of the different Hemagglutinin sequences elucidated that the single block 7 has the highest frequency of amino acid substitution and the highest number of co-mutating pairs. MEME 2 showed intermediate variability and MEME 1 was the most conserved. Interestingly, MEME blocks 2 and 7 had the highest incidence of potential post-translational modifications sites including phosphorylation sites, ASN glycosylation motifs and N-myristylation sites. Similarly, these 2 blocks overlap with previously identified antigenic sites and receptor binding sites.</p> <p>Conclusion</p> <p>Our study identifies motifs in the Hemagglutinin protein with different amino acid substitution frequencies over a 31 years period, and derives relevant functional characteristics by correlation of these motifs with potential post-translational modifications sites, antigenic and receptor binding sites.</p

Entropy per rapidity in Pb-Pb central collisions using Thermal and Artificial neural network(ANN) models at LHC energies

The entropy per rapidity $d S/d y$ produced in central Pb-Pb ultra-relativistic nuclear collisions at LHC energies is calculated using experimentally observed identified particle spectra and source radii estimated from Hanbury Brown-Twiss (HBT) for particles, $\pi$, $k$, $p$, $\Lambda$, $\Omega$, and $\bar{\Sigma}$, and $\pi$, $k$, $p$, $\Lambda$ and $K_s^0$ at $\sqrt{s}$ $=2.76$ and $5.02$ TeV, respectively. Artificial neural network (ANN) simulation model is used to estimate the entropy per rapidity $d S/d y$ at the considered energies. The simulation results are compared with equivalent experimental data, and good agreement is achieved. A mathematical equation describes experimental data is obtained. Extrapolating the transverse momentum spectra at $p_T$ $=0$ is required to calculate $d S/d y$ thus we use two different fitting functions, Tsallis distribution and the Hadron Resonance Gas (HRG) model. The success of ANN model to describe the experimental measurements will imply further prediction for the entropy per rapidity in the absence of the experiment

AcDc - A new code for the NLTE spectral analysis of accretion discs: application to the helium CV AM CVn

We present a recently developed code for detailed NLTE calculations of accretion disc spectra of cataclysmic variables and compact X-ray binaries. Assuming a radial structure of a standard alpha-disc, the disc is divided into concentric rings. For each disc ring the solution of the radiation transfer equation and the structure equations, comprising the hydrostatic and radiative equilibrium, the population of the atomic levels as well as charge and particle conservation, is done self-consistently. Metal-line blanketing and irradiation by the central object are taken into account. As a first application, we show the influence of different disc parameters on the disc spectrum for the helium cataclysmic variable AM CVn.Comment: 7 pages, 11 figures to be published in A&

Ontogeny of bradykinin B2 receptors in the rat kidney: Implications for segmental nephron maturation

Ontogeny of bradykinin B2 receptors in the rat kidney: Implications for segmental nephron maturation. Kinins modulate renal function, yet their role in the developing kidney is largely unknown. To explore the developmental role of the kallikrein-kinin system, we examined the postnatal ontogeny and intrarenal localization of B2 receptors in the rat. Northern blot analysis and RT-PCR documented the expression of B2 receptor mRNA in the kidney and extrarenal tissues of fetal, neonatal and adult animals. The abundance of B2 receptor mRNA is 10- to 30-fold higher in neonatal than adult tissues in the following order: kidney > heart > aorta > lung > brain. Receptor autoradiography revealed a gradual shift in the localization of bradykinin binding sites from the outer cortex in the newborn to the outer medulla in weanling and maturing rats. The almost complete displacement of [125I]tyr0-bradykinin by HOE-140 indicates that the majority of kinin receptors in the developing kidney belong to the B2 type. Immunolocalization studies using antipeptide antibodies directed against various portions of the receptor revealed that B2 receptors are first expressed on the luminal aspect of the upper limb of S-shaped bodies and differentiating cortical collecting ducts. In marked contrast, the metanephric mesenchyme, pretubular aggregates and glomeruli display weak or no B2 receptor immunoreactivity. Following completion of nephrogenesis, B2 receptor expression shifts to both luminal and basolateral aspects of connecting tubules and collecting ducts. The results demonstrate that bradykinin B2 receptor gene expression is activated in the developing kidney and cardiovascular system. The spatially restricted expression of B2 receptors in the differentiating epithelium of the distal nephron, the site of kinin formation, supports the hypothesis that kinins are paracrine modulators of segmental nephron maturation

The identification and characterization of a novel protein, c19orf10, in the synovium

Joint inflammation and destruction have been linked to the deregulation of the highly synthetic fibroblast-like synoviocytes (FLSs), and much of our current understanding of the mechanisms that underlie synovitis has been collected from studies of FLSs. During a proteomic analysis of FLS cells, we identified a novel protein, c19orf10 (chromosome 19 open reading frame 10), that was produced in significant amounts by these cells. The present study provides a partial characterization of c19orf10 in FLSs, synovial fluid, and the synovium. Murine monoclonal and chicken polyclonal antibodies were produced against recombinant human c19orf10 protein and used to examine the distribution of c19orf10 in cultured FLSs and in synovial tissue sections from patients with rheumatoid arthritis or osteoarthritis. The intracellular staining pattern of c19orf10 is consistent with localization in the endoplasmic reticulum/Golgi distribution. Sections of rheumatoid arthritis and osteoarthritis synovia expressed similar patterns of c19orf10 distribution with perivascular and synovial lining staining. Double-staining in situ analysis suggests that fibroblast-like synovial cells produced c19orf10, whereas macrophages, B cells, or T cells produced little or none of this protein. There is evidence of secretion into the vascular space and the extracellular matrix surrounding the synovial lining. A competitive enzyme-linked immunosorbent assay confirmed the presence of microgram levels of c19orf10 in the synovial fluids of patients with one of various arthropathies. Collectively, these results suggest that c19orf10 is an FLS-derived protein that is secreted into the synovial fluid. However, the significance of this protein in synovial biology remains to be determined. The absence of known structural motifs or domains and its relatively late evolutionary appearance raise interesting questions about its function

Prospects for Spin Physics at RHIC

Colliding beams of 70% polarized protons at up to $\sqrt{s}$=500 GeV, with high luminosity, L=2$\times10^{{\rm 32}}$ cm$^{-2}$sec$^{-1}$, will represent a new and unique laboratory for studying the proton. RHIC-Spin will be the first polarized-proton collider and will be capable of copious production of jets, directly produced photons, and $W$ and $Z$ bosons. Features will include direct and precise measurements of the polarization of the gluons and of $\bar{u}$, $\bar{d}$, $u$, and $d$ quarks in a polarized proton. Parity violation searches for physics beyond the standard model will be competitive with unpolarized searches at the Fermilab Tevatron. Transverse spin will explore transversity for the first time, as well as quark-gluon correlations in the proton. Spin dependence of the total cross section and in the Coulomb nuclear interference region will be measured at collider energies for the first time. These qualitatively new measurements can be expected to deepen our understanding of the structure of matter and of the strong interaction.Comment: 51 pages, 22 figures. Scheduled to appear in the Annual Review of Nuclear and Particle Science Vol. 50, to be published in December 2000 by Annual Reviews, http://AnnualReviews.or

On the evolution of superposition of squeezed displaced number states with the multiphoton Jaynes-Cummings model

In this paper we discuss the quantum properties for superposition of squeezed displaced number states against multiphoton Jaynes-Cummings model (JCM). In particular, we investigate atomic inversion, photon-number distribution, purity, quadrature squeezing, Mandel $Q$ parameter and Wigner function. We show that the quadrature squeezing for three-photon absorption case can exhibit revivals and collapses typical to those occurring in the atomic inversion for one-photon absorption case. Also we prove that for odd number absorption parameter there is a connection between the evolution of the atomic inversion and the evolution of the Wigner function at the origin in phase space. Furthermore, we show that the nonclassical states whose the Wigner functions values at the origins are negative will be always nonclassical when they are evolving through the JCM with even absorption parameter. Also we demonstrate that various types of cat states can be generated via this system.Comment: 27 pages, 10 figure