NN interaction in a Goldstone boson exchange model

Adiabatic nucleon-nucleon potentials are calculated in a six-quark nonrelativistic chiral constituent quark model where the Hamiltonian contains a linear confinement and a pseudoscalar meson (Goldstone boson) exchange interaction between quarks. Calculations are performed both in a cluster model and a molecular orbital basis, through coupled channels. In both cases the potentials present an important hard core at short distances, explained through the dominance of the [51]_{FS} configuration, but do not exhibit an attractive pocket. We add a scalar meson exchange interaction and show how it can account for some middle-range attraction.Comment: 32 pages with 12 eps figures incorporated, RevTeX. Final version published in PR

T-DNA integration patterns in transgenic maize lines mediated by Agrobacterium tumefaciens

To explore transfer deoxyribonucleic acid (T-DNA) integration patterns in the maize genome, we improved the protocol of thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR), and amplified the flanking sequences around T-DNA integration sites from 70 independent transgenic maize lines mediated by Agrobacterium tumefaciens. Out of 64 specific amplified fragments, 32 and 9 are homologous to the sequences of the maize genome and the expression plasmid, respectively. For 26 of them, a filler sequence was found flanking the cleavage sites. These results demonstrate that cleavage occurs not only during the T-DNA borders but also inside or outside the borders. The border sequences and some inside sequences can be deleted, and filler sequences can be inserted. Illegitimate recombination is a major pattern of T-DNA integration, while some hot spots and preference are present on maize chromosomes.Key words: Agrobacterium tumefaciens, maize, thermal asymmetric interlaced PCR, transfer DNA,transgenics

Identification and Characterization of MicroRNAs in Asiatic Cotton (Gossypium arboreum L.)

To date, no miRNAs have been identified in the important diploid cotton species although there are several reports on miRNAs in upland cotton. In this study, we identified 73 miRNAs, belonging to 49 families, from Asiatic cotton using a well-developed comparative genome-based homologue search. Several of the predicted miRNAs were validated using quantitative real time PCR (qRT-PCR). The length of miRNAs varied from 18 to 22 nt with an average of 20 nt. The length of miRNA precursors also varied from 46 to 684 nt with an average of 138 ±120 nt. For a majority of Asiatic cotton miRNAs, there is only one member per family; however, multiple members were identified for miRNA 156, 414, 837, 838, 1044, 1533, 2902, 2868, 5021 and 5142 families. Nucleotides A and U were dominant, accounted for 62.95%, in the Asiatic cotton pre-miRNAs. The Asiatic cotton pre-miRNAs had high negative minimal folding free energy (MFE) and adjusted MFE (AMFE) and high MFE index (MFEI). Many miRNAs identified in Asiatic cotton suggest that miRNAs also play a similar regulatory mechanism in diploid cotton

Co-seismic ground deformation of Yushu Earthquake detected with D-InSAR technique

An earthquake of magnitude 7.1 suddenly occurred in Yushu county of Qinghai province on April 14, 2010. This paper presents the studies of using the data of Advanced Land Observing Satellite-Phased Array type L-band Synthetic Aperture Radar (ALOS-PALSAR) before and after the earthquake to examine and calculate the co-seismic ground deformation. The differential SAR interferometry (D-InSAR) technique is used. The results show that the earthquake caused the ground deformation over a large area. The extension of the ground deformation followed the south-east to east direction and along the Yushu-Ganzi fault zone. The largest deformation was found about 350 mm at 33.7°N 96.81°E. It is along the line of sight (LOS) of SAR and can be detected with D-InSAR technique. The detected ground deformation was mainly uplifting. The detected ground deformation has an important value for evaluating the extent of ground damage and seismicity in Yushu after earthquake, inferring the nature of the quake faulting, and studying characteristics of seismic deformation. 2010-04-14青海玉树发生7.1级地震后, 作者利用震前和震后获取的日本ALOS卫星PALSAR遥感数据, 开展了差分干涉雷达(D-InSAR)地震同震形变测量与分析。结果表明: 玉树地震引起较大范围地表变形, 地震变形沿玉树—甘孜断裂带向南东东方向扩展, 在N33.7°, E96.81°附近达到最大形变量, D-InSAR监测到雷达视向上的最大形变量为35cm。地表形变特征对于评价玉树地震破坏程度、推断断层性质、研究地震形变和地震孕育特征具有重要的参考价值

The Nucleon-Nucleon Interaction in a Chiral Constituent Quark Model

We study the short-range nucleon-nucleon interaction in a chiral constituent quark model by diagonalizing a Hamiltonian comprising a linear confinement and a Goldstone boson exchange interaction between quarks. The six-quark harmonic oscillator basis contains up to two excitation quanta. We show that the highly dominant configuration is $\mid s^4p^2[42]_O [51]_{FS}>$ due to its specific flavour-spin symmetry. Using the Born-Oppenheimer approximation we find a strong effective repulsion at zero separation between nucleons in both $^3S_1$ and $^1S_0$ channels. The symmetry structure of the highly dominant configuration implies the existence of a node in the S-wave relative motion wave function at short distances. The amplitude of the oscillation of the wave function at short range will be however strongly suppressed. We discuss the mechanism leading to the effective short-range repulsion within the chiral constituent quark model as compared to that related with the one-gluon exchange interaction.Comment: 31 pages, LaTe

Bilinear Quantum Monte Carlo: Expectations and Energy Differences

We propose a bilinear sampling algorithm in Green's function Monte Carlo for expectation values of operators that do not commute with the Hamiltonian and for differences between eigenvalues of different Hamiltonians. The integral representations of the Schroedinger equations are transformed into two equations whose solution has the form $\psi_a(x) t(x,y) \psi_b(y)$, where $\psi_a$ and $\psi_b$ are the wavefunctions for the two related systems and $t(x,y)$ is a kernel chosen to couple $x$ and $y$. The Monte Carlo process, with random walkers on the enlarged configuration space $x \otimes y$, solves these equations by generating densities whose asymptotic form is the above bilinear distribution. With such a distribution, exact Monte Carlo estimators can be obtained for the expectation values of quantum operators and for energy differences. We present results of these methods applied to several test problems, including a model integral equation, and the hydrogen atom.Comment: 27 page

Increased NBCn1 expression, Na+/HCO3- co-transport and intracellular pH in human vascular smooth muscle cells with a risk allele for hypertension.

Genome-wide association studies have revealed an association between variation at the SLC4A7 locus and blood pressure. SLC4A7 encodes the electroneutral Na+/HCO3- co-transporter NBCn1 which regulates intracellular pH (pHi). We conducted a functional study of variants at this locus in primary cultures of vascular smooth muscle and endothelial cells. In both cell types, we found genotype-dependent differences for rs13082711 in DNA-nuclear protein interactions, where the risk allele is associated with increased SLC4A7 expression level, NBCn1 availability and function as reflected in elevated steady-state pHi and accelerated recovery from intracellular acidosis. However, in the presence of Na+/H+ exchange activity, the SLC4A7 genotypic effect on net base uptake and steady-state pHi persisted only in vascular smooth muscle cells but not endothelial cells. We found no discernable effect of the missense polymorphism resulting in the amino acid substitution Glu326Lys. The finding of a genotypic influence on SLC4A7 expression and pHi regulation in vascular smooth muscle cells provides an insight into the molecular mechanism underlying the association of variation at the SLC4A7 locus with blood pressure

The d* dibaryon in the extended quark-delocalization, color-screening model

The quark-delocalization, color-screening model, extended by inclusion of a one-pion-exchange (OPE) tail, is applied to the study of the deuteron and the d* dibaryon. The results show that the properties of the deuteron (an extended object) are well reproduced, greatly improving the agreement with experimental data as compared to our previous study (without OPE). At the same time, the mass and decay width of the d* (a compact object) are, as expected, not altered significantly.Comment: 9 pages, no figures, LaTeX, subm. to Phys. Rev.