Fission product gamma spectra

The fission product gamma spectra of /sup 233/U, /sup 235/U, and /sup 239/Pu were measured at 12 cooling times following 20,000-s irradiations in the thermal column of the Omega West Reactor. The mean cooling times ranged from 29 s to 146,500 s. The total gamma energies were obtained by integrating over the energy spectra, and both the spectra and the total energies are compared with calculations using the CINDER-10 code and ENDF/B-IV data base. The measured and calculated gamma spectra are compared in a series of figures. The measured total gamma energies are approx. 14% larger than the calculated energies during the earliest counting period (4 s to 54 s cooling time). For /sup 235/U, the measured and calculated total gamma energies are nearly the same after 1200 s cooling time, and the measurements are 2% to 6% lower at longer cooling times. For /sup 239/Pu, the measured and calculated total gamma energies are nearly the same at cooling times longer than 4,000 s, and for /sup 233/U this condition prevails at cooling times longer than 10,000 s. 39 figures, 4 tables

Realistic Calculation of the hep Astrophysical Factor

The astrophysical factor for the proton weak capture on 3He is calculated with correlated-hyperspherical-harmonics bound and continuum wave functions corresponding to a realistic Hamiltonian consisting of the Argonne v18 two-nucleon and Urbana-IX three-nucleon interactions. The nuclear weak charge and current operators have vector and axial-vector components, that include one- and many-body terms. All possible multipole transitions connecting any of the p-3He S- and P-wave channels to the 4He bound state are considered. The S-factor at a p-3He center-of-mass energy of 10 keV, close to the Gamow-peak energy, is predicted to be 10.1 10^{-20} keV b, a factor of five larger than the standard-solar-model value. The P-wave transitions are found to be important, contributing about 40 % of the calculated S-factor.Comment: 8 pages RevTex file, submitted to Phys. Rev. Let

RhoE Deficiency Produces Postnatal Lethality, Profound Motor Deficits and Neurodevelopmental Delay in Mice

Rnd proteins are a subfamily of Rho GTPases involved in the control of actin cytoskeleton dynamics and other cell functions such as motility, proliferation and survival. Unlike other members of the Rho family, Rnd proteins lack GTPase activity and therefore remain constitutively active. We have recently described that RhoE/Rnd3 is expressed in the Central Nervous System and that it has a role in promoting neurite formation. Despite their possible relevance during development, the role of Rnd proteins in vivo is not known. To get insight into the in vivo function of RhoE we have generated mice lacking RhoE expression by an exon trapping cassette. RhoE null mice (RhoE gt/gt) are smaller at birth, display growth retardation and early postnatal death since only half of RhoE gt/gt mice survive beyond postnatal day (PD) 15 and 100% are dead by PD 29. RhoE gt/gt mice show an abnormal body position with profound motor impairment and impaired performance in most neurobehavioral tests. Null mutant mice are hypoactive, show an immature locomotor pattern and display a significant delay in the appearance of the hindlimb mature responses. Moreover, they perform worse than the control littermates in the wire suspension, vertical climbing and clinging, righting reflex and negative geotaxis tests. Also, RhoE ablation results in a delay of neuromuscular maturation and in a reduction in the number of spinal motor neurons. Finally, RhoE gt/gt mice lack the common peroneal nerve and, consequently, show a complete atrophy of the target muscles. This is the first model to study the in vivo functions of a member of the Rnd subfamily of proteins, revealing the important role of Rnd3/RhoE in the normal development and suggesting the possible involvement of this protein in neurological disorders

Thermal-neutron capture in light nuclei

We have made considerable progress toward the goal of carrying out thermal-neutron capture {gamma}-ray measurements on all stable isotopes below A=60. Information processed till now has significantly augmented the existing knowledge on the detailed nuclear level structure of many light nuclides. Most of this knowledge comes from our {gamma}-ray energies, level placements, and branching ratios of secondary transitions between low-lying states. Spectroscopic information is also contained in the cross sections of the primary transitions originating from the capturing state. This is deduced from the success of ``direct`` theories of neutron capture for many nuclides, especially those of light and near closed-shell character. 23 refs, 1 tab, 3 figs

Thermal neutron absorption cross section of sulfur and the 252-californium nubar problem

The thermal neutron absorption cross section for natural sulfur was measured to be 513 +- 15 mb. Any discrepancy between MnSO/sub 4/-bath and liquid scintillator measurements of /sup 252/Cf(anti ..nu..) cannot be attributed to a discrepancy in this cross section value