Target structure independent 7Li⃗^7\vec{Li} elastic scattering at low momentum transfers

Analyzing powers and cross sections for the elastic scattering of polarized 7Li by targets of 6Li, 7Li and 12C are shown to depend only on the properties of the projectile for momentum transfers of less than 1.0 fm-1. The result of a detailed analysis of the experimental data within the framework of the coupled channels model with ground state reorientation and transitions to the excited states of the projectile and targets included in the coupling schemes are presented. This work suggests that nuclear properties of weakly-bound nuclei can be tested by elastic scattering experiments, independent of the target used, if data are acquired for momentum transfers less than ~1.0 fm-1.Comment: 9 pages, 4 figures, 1 table, accepted in Phys. Lett.

Identification of common genetic risk variants for autism spectrum disorder

Autism spectrum disorder (ASD) is a highly heritable and heterogeneous group of neurodevelopmental phenotypes diagnosed in more than 1% of children. Common genetic variants contribute substantially to ASD susceptibility, but to date no individual variants have been robustly associated with ASD. With a marked sample-size increase from a unique Danish population resource, we report a genome-wide association meta-analysis of 18,381 individuals with ASD and 27,969 controls that identified five genome-wide-significant loci. Leveraging GWAS results from three phenotypes with significantly overlapping genetic architectures (schizophrenia, major depression, and educational attainment), we identified seven additional loci shared with other traits at equally strict significance levels. Dissecting the polygenic architecture, we found both quantitative and qualitative polygenic heterogeneity across ASD subtypes. These results highlight biological insights, particularly relating to neuronal function and corticogenesis, and establish that GWAS performed at scale will be much more productive in the near term in ASD.Peer reviewe

Spin and parity determinations of excited 15^{15}N based on polarized and unpolarized 12^{12}C(7^7Li, α\alpha)15^{15}N reaction data at Elab_{lab} = 34 MeV

International audienceFrom an experiment conducted at the Florida State University Accelerator Laboratory with a 34 MeV polarized Li-7 beam bombarding a C-12 target, we have obtained angular distributions and analyzing powers for states of N-15 up to 20 MeV in excitation energy. This study not only offers the possibility to assign spin and parity to several states in N-15, but also serves to obtain nuclear potential parameters used in Distorted Wave Born (DWBA) and Coupled Channel Born (CCBA) Approximations to generate theoretical angular distributions and vector analyzing powers that give the best description of the experimental data. Under the assumption that the reaction mechanism is a three nucleon transfer, the determination of shell model nucleonic configurations and spectroscopic factors is possible for the N-15 states studie

Survey of 17^{17}O excited states selectively populated by five-particle transfer reactions

The highly selective reactions 12C(7Li,d)17O and 12C(6Li,p)17O have been used to populate high-lying excited states in 17O up to 16 MeV in excitation. Several of the states are newly observed, and the existence of others in a previous study of 12C(6Li,p)17O is confirmed. The observed spectra show a clear gap of about 3 MeV, indicating an energy gap between 3p-2h and 5p-4h states in 17O. Differential cross section angular distributions have been extracted from the data for both reactions and they have been compared with finite-range DWBA calculations by assuming a “5He” cluster transfer. Possible spins and parities are reported for states at 11.82 MeV (7/2+), 12.00 MeV (9/2+),12.22 MeV (7/2-), and 12.42 MeV (9/2+)

Analyzing powers and the role of multistep processes in the 12C(7Li,t)16O^{12}\mathrm{C}(^{7}\mathrm{Li},t)^{16}\mathrm{O} reaction

International audienceThe analyzing powers T10T,T20T, and T30T for the C12(Li7,t) reaction were measured and combined with new and previously determined angular distributions to probe the role of multistep processes through coupled channel Born approximation (CCBA) calculations employing new α-particle spectroscopic amplitudes calculated with the phenomenological shell model in the unrestricted psd space. Good descriptions of the cross-section angular distributions could be obtained except for the larger angles for the 6.05 MeV 0+ and 6.13 MeV 3− states, while the analyzing powers were not generally described. The calculations presented demonstrate the sensitivity of the angular distributions of both the differential cross sections and the analyzing powers to various multistep routes. While the measured analyzing power T30T is roughly zero for all states, the various CCBA calculations produced large and highly oscillatory values for this observable, showing that other multistep processes must be present beyond those taken into account in this work. Standard distorted wave Born approximation (DWBA) calculations were also carried out and these show considerable differences from the CCBA results but the description of the analyzing powers, while slightly improved, is still poor

Direct radiative proton capture 23Al(p,α\alpha)24Si studied via one-proton nuclear breakup of 24Si

Expérience GANIL/SPEGInternational audienceWe present the results of an experimental work that studied the direct component of the radiative proton capture reaction 23Al(p,$\gamma$)24Si for its relevance in X-ray burst nucleosynthesis. The experiment was performed at GANIL using one-proton nuclear breakup reaction at intermediate energies to determine the Asymptotic Normalization Coefficient (ANC) of the system 24Si $\rightarrow$ 23Al + p. Using the ANC, we evaluated the corresponding astrophysical S factor and reaction rate

SYT associates with human SNF/SWI complexes and the C-terminal region of its fusion partner SSX1 targets histones.

Item does not contain fulltextA global transcriptional co-activator, the SNF/SWI complex, has been characterized as a chromatin remodeling factor that enhances accessibility of the transcriptional machinery to DNA within a repressive chromatin structure. On the other hand, mutations in some human SNF/SWI complex components have been linked to tumor formation. We show here that SYT, a partner protein generating the synovial sarcoma fusion protein SYT-SSX, associates with native human SNF/SWI complexes. The SYT protein has a unique QPGY domain, which is also present in the largest subunits, p250 and the newly identified homolog p250R, of the corresponding SNF/SWI complexes. The C-terminal region (amino acids 310-387) of SSX1, comprising the SSX1 portion of the SYT-SSX1 fusion protein, binds strongly to core histones and oligonucleosomes in vitro and directs nuclear localization of a green fluorescence protein fusion protein. Experiments with serial C-terminal deletion mutants of SSX1 indicate that these properties map to a common region and also correlate with the previously demonstrated anchorage-independent colony formation activity of SYT-SSX in Rat 3Y1 cells. These data suggest that SYT-SSX interferes with the function of either the SNF/SWI complexes or another SYT-interacting co-activator, p300, by changing their targeted localization or by directly inhibiting their chromatin remodeling activities

Direct fusion measurement of the ⁸B proton-halo nucleus at near-barrier energies

Direct measurements of the total fusion cross section for 8B + 40Ar were achieved with the active target technique. The fusion excitation function was extracted at energies near the Coulomb barrier. The cross section is well described by a coupled reaction channels calculation. The data were compared with previous 8B fusion experiments on 28Si and 58Ni targets. No evidence of striking enhancement of the total fusion cross section at near the Coulomb barrier, that was previously reported for the 8B + 58Ni system, was observed in these direct measurements. The present data are systematically consistent with the results for 8B+28Si at higher energies and with other weakly-bound systems at near-barrier energies