Impact of Clustering on the

We place unprecedented constraints on recoil corrections in the ß decay of ^{8}Li, by identifying a strong correlation between them and the ^{8}Li ground state quadrupole moment in large-scale ab initio calculations. The results are essential for improving the sensitivity of high-precision experiments that probe the weak interaction theory and test physics beyond the standard model. In addition, our calculations predict a 2^{+} state of the α+α system that is energetically accessible to ß decay but has not been observed in the experimental ^{8}Be energy spectrum, and has an important effect on the recoil corrections and ß decay for the A=8 systems. This state and an associated 0^{+} state are notoriously difficult to model due to their cluster structure and collective correlations, but become feasible for calculations in the ab initio symmetry-adapted no-core shell-model framework.

Physics of Nuclei: Key Role of an Emergent Symmetry.

We show through first-principles nuclear structure calculations that the special nature of the strong nuclear force determines highly regular patterns heretofore unrecognized in nuclei that can be tied to an emergent approximate symmetry. This symmetry is ubiquitous and mathematically tracks with a symplectic symmetry group. This, in turn, has important implications for understanding the physics of nuclei: we find that nuclei are made of only a few equilibrium shapes, deformed or not, with associated vibrations and rotations. It also opens the path for ab initio large-scale modeling of open-shell intermediate-mass nuclei without the need for renormalized interactions and effective charges.

Collective modes in light nuclei from first principles.

Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of 6Li, 8Be, and 6He are shown to exhibit orderly patterns that favor spatial configurations with strong quadrupole deformation and complementary low intrinsic spin values, a picture that is consistent with the nuclear symplectic model. The results also suggest a pragmatic path forward to accommodate deformation-driven collective features in ab initio analyses when they dominate the nuclear landscape.

Strong hyperon-nucleon pairing in neutron stars.

We explore the possibilities of hyperon-nucleon pairing, involving lambda or sigma- hyperons, using different Nijmegen hyperon-nucleon potentials. We find possible very large nsigma- gaps and estimate their relevance for neutron star physics.

Physical significance of q deformation and many-body interactions in nuclei.

The quantum deformation concept is applied to a study of pairing correlations in nuclei with mass 40< or =A< or =100. While the nondeformed limit of the theory provides a reasonable overall description of certain nuclear properties and fine structure effects, the results show that the q deformation plays a significant role in understanding higher-order effects in the many-body interaction.

Algebraic solutions of an extended pairing model for well deformed nuclei.

A Nilsson mean-field plus extended pairing interaction Hamiltonian with many-pair interaction terms is proposed. Eigenvalues of the extended pairing model are easy to obtain. Our investigation shows that one- and two-body interactions continue to dominate the dynamics for relatively small values of the pairing strength. As the strength of the pairing interaction grows, however, the three- and higher many-body interaction terms grow in importance. A numerical study of even-odd mass differences in the (154-171)Yb isotopes shows that the extended pairing model is applicable to well deformed nuclei.

Amyloid enhancing factor in hamster.

An amyloid enhancing factor (AEF) was extracted from spleens and livers of casein-treated hamsters. It shortened the induction time of experimental amyloidosis in recipient hamsters from 14 days to 4 days. Sepharose-4B gel filtration resolved the extract into 4 different fractions, with molecular weights of: higher than IO(7) (Vo-fraction), about 280 000, 59 000 and 12 000 respectively. In all 4 fractions AEF was present, indicating that AEF is probably a low molecular weight substance that easily aggregates, or associates with other compounds present in the spleen extract. AEF was precipitable at 50% ammonium sulphate saturation. On anion exchange chromatography in PBS (pH 7.2) of this precipitate, AEF was found in the fraction eluting at high NaCl concentration. This fraction did not show any relation to hamster protein AA, IgG or albumin with double immunodiffusion. Ultraviolet absorption spectrophotometry indicated nucleotide-like material, suggesting AEF to be related to nucleoproteins.