Magnetic moments of exotic pentaquark baryons

In this talk, we present our recent investigation on the magnetic moments of the exotic pentaquark states, based on the chiral quark-soliton model, all relevant intrinsic parameters being fixed by using empirical data.Comment: 5 pages, 1 figure, a talk presented at the 10th International Conference on Baryons (Baryons04), Palaiseau, October 25-29, 200

Magnetic and axial-vector transitions of the baryon antidecuplet

We report the recent results of the magnetic transitions and axial-vector transitions of the baryon antidecuplet within the framework of the chiral quark-soliton model. The dynamical model parameters are fixed by experimental data for the magnetic moments of the baryon octet, for the hyperon semileptonic decay constants, and for the singlet axial-vector constant. The transition magnetic moments $\mu_{\Lambda\Sigma}$ and $\mu_{N\Delta}$ are well reproduced and other octet-decuplet and octet-antidecuplet transitions are predicted. In particular, the present calculation of $\mu_{\Sigma\Sigma^*}$ is found to be below the upper bound $0.82\mu_N$ that the SELEX collaboration measured very recently. The results explains consistently the recent findings of a new $N^*$ resonance from the GRAAL and Tohoku LNS group. We also obtain the transition axial-vector constants for the $\Theta^+\to KN$ from which the decay width of the $\Theta^{+}$ pentaquark baryon is determined as a function of the pion-nucleon sigma term $\Sigma_{\pi N}$. We investigate the dependence of the decay width of the $\Theta^{+}$ on the $g_{A}^{(0)}$, with the $g_{A}^{(0)}$ varied within the range of the experimental uncertainty. We show that a small decay width of the $\Theta^{+}\to KN$, i.e. $\Gamma_{\Theta KN} \leq 1$ MeV, is compatible with the values of all known semileptonic decays with the generally accepted value of $g_{A}^{(0)} \approx 0.3$ for the proton.Comment: 8 pages, 5 figures, Talk given at the Yukawa International Seminar (YKIS) 2006, "New frontiers in QCD", Kyoto, Japan, 20 Nov. - 8 Dec. 200

Identification of functional genetic variants modulating the stress response

Stress and exposure to stressful life events are some of the strongest risk factors for the development of psychiatric disorders. While it is known that genetic factors play an important role in one?s response to stress, the genetic variants driving differences in the stress response have yet to be determined. Using an expression trait quantitative loci (eQTL) approach, previous research from our group identified over 3600 genetic variants associated with altered transcriptional activity upon activation of the glucocorticoid receptor (GR), a key transcription factor in the stress response system. These variants (GR-eQTLs) were enriched in GR binding sites and putative regulatory elements, and predicted case-control status for major depressive disorder, as well as amygdala activity in an emotional reactivity task. However, due to linkage disequilibrium, the functional variants driving these transcriptional changes remain unidentified.In order to identify which of the GR-eQTLs had a functional effect on GR mediated transcription, we performed STARR-sequencing, an approach allowing thousands of DNA sequences to be assessed for regulatory element activity in parallel. This allowed us to determine the effect of each GR-eQTL on transcriptional activity at baseline and after GR activation with dexamethasone (dex) in GR18 and U138MG cells. STARR-seq revealed that 1220 variants were located in active regulatory elements, either at baseline or after dex. Of these, 547 variants show differential transcriptional activity after dex treatment (DREs). These were enriched in GR-binding sites determined by ChIP-seq, as well as chromatin loop anchor points. Next, DREs with allele dependent activity at baseline and after dex were identified. We found 165 DREs to show allele dependent activity at baseline, and 172 DREs after dex. Both the baseline and dex functional variants showed a significant overlap with variants nominally associated with psychiatric disorders from the latest psychiatric cross disorder meta-analysis GWAS. Furthermore, using Mendelian Randomization, nineteen and eleven DREs with allele-dependent activity in the dex and veh condition, respectively, were identified to have a putative causal effect on psychiatric disorders. These results suggest that the loci modulating the transcriptomic response to stress are putatively causally associated with psychopathology

Automated Retrieval of Non-Engineering Domain Solutions to Engineering Problems

Organised by: Cranfield UniversityBiological inspiration for engineering design has occurred through a variety of techniques such as creation and use of databases, keyword searches of biological information in natural-language format, prior knowledge of biology, and chance observations of nature. This research focuses on utilizing the reconciled Functional Basis function and flow terms to identify suitable biological inspiration for function based design. The organized search provides two levels of results: (1) associated with verb function only and (2) narrowed results associated with verb-noun (function-flow). A set of heuristics has been complied to promote efficient searching using this technique. An example for creating smart flooring is also presented and discussed.Mori Seiki – The Machine Tool Compan

Relations between generalized and transverse momentum dependent parton distributions

Recent work suggests non-trivial relations between generalized parton distributions on the one hand and (naive time-reversal odd) transverse momentum dependent distributions on the other. Here we review the present knowledge on such type of relations. Moreover, as far as spectator model calculations are concerned, the existing results are considerably extended. While various relations between the two types of parton distributions can be found in the framework of spectator models, so far no non-trivial model-independent relations have been established.Comment: 25 pages, 9 figures; Eq. (B17) and typos corrected, identical with journal versio

Meson twist-4 parton distributions in terms of twist-2 distribution amplitudes at large Nc

We show that in the large N_c limit four-quark twist-4 distributions in the pion can be expressed in terms of twist-2 pion distribution amplitude. This allows us to compute the isospin-2 structure function of the pion F_2^{I=2}(x_B) in the large N_c limit. The method can be easily applied to other mesons as well.Comment: 6 pages, one figur

Generalized parton distributions in a meson cloud model

We present a model calculation of the generalized parton distributions where the nucleon is described by a quark core surrounded by a mesonic cloud. In the one-meson approximation, we expand the Fock state of the physical nucleon in a series involving a bare nucleon and two-particle, meson-baryon, states. We discuss the role of the different Fock-state components of the nucleon by deriving a convolution formalism for the unpolarized generalized parton distributions, and showing predictions at different kinematics.Comment: 7 pages, 3 figures; Invited talk at the Fifth International Conference on Perspectives in Hadronic Physics, Miramare - Trieste (Italy), 22-26 May 200