Study of α-transfer reaction 28Si( 7Li, t) 32S

The 28Si( 7Li, t) 32S reaction has been studied at 48 MeV. Using a αt potential overlap based on a microscopic cluster model, the full finite-range distorted wave Born approximation analysis was carried out for nine low-lying states; 0.0 MeV (0+), 2.23 MeV (2+), 3.78 MeV (0+), 4.46 MeV (4+), 5.01 MeV (3-), 5.80 MeV (1-), 6.76 MeV (3-), 7.43 MeV (1-) and 8.49 MeV (1-) of the residual nucleus. A re-analysis was also done for the same states of 32S having an αd overlap for the reaction 28Si (6Li, d) 32S at 75.6 MeV. Theoretical spectroscopic factors have been calculated for the measured even-parity states of 32S using the shell model code OXBASH. The spectroscopic factors were compared for both the reactions

Wide-angle α-t coincidence measurement in the breakup of 7Li on 27Al

We have performed wide-angle in-plane coincidence measurements of the alpha particles and tritons emitted in the 48-MeV 7Li projectile breakup reaction on 27Al. The data have been analyzed using the post-form distorted-wave Born-approximation (DWBA) theory of breakup reactions where Coulomb and nuclear breakup as well as their interference terms are included. The theory is able to provide a good description of the experimental data particularly at large relative angles between the fragments. The interference between the Coulomb and nuclear breakup modes is found to be significant

Inclusive and exclusive measurements in the projectile breakup of 7Li

The inclusive and exclusive measurements were carried out for 7Li projectile breakup on 27Al target at 48 MeV. In the inclusive data we have observed a broad peak around the beam velocity for alphas and tritons. The exclusive data for alpha-triton coincidences show good agreement with the post-form DWBA theory of breakup reactions

Underestimation of microzooplankton grazing in dilution experiments due to inhibition of phytoplankton growth

Microzooplankton dilution grazing experiments conducted in phytoplankton rich waters, particularly in polar and subpolar seas, often result in calculation of nonsignificant or negative grazing coefficients. We hypothesized that preparation of filtered seawater (FSW) from water containing high biomass of phytoplankton results in release of allelochemicals that inhibit phytoplankton growth, lowering the net growth of phytoplankton in the more diluted treatments. We tested this hypothesis during blooms of Skeletonema marinoi and Phaeocystis pouchetii in a nutrient-enriched mesocosm in the Raunefjord, Norway. During the S. marinoi bloom, inhibition of phytoplankton growth occurred in the diluted treatments. Simultaneously the concentration of total as well as dissolved polyunsaturated aldehydes (PUAs) was elevated. Passage of the FSW through a carbon cellulose cartridge to remove dissolved organic material reduced, or eliminated, the inhibition. In the early phase of the P. pouchetii bloom that followed the diatom bloom in the mesocosm, PUA concentration was relatively low and the untreated FSW had a less drastic, but often significant, inhibitory effect on phytoplankton growth. Laboratory experiments with cultures of S. marinoi and P. pouchetii confirmed that material present in filtrate prepared from diluted cultures was self-inhibitory. Many phytoplankters, particularly during late stages of a bloom, produce inhibitory metabolites that may be released during filtration of the relatively large volumes of seawater needed for dilution experiments. Under some conditions, dilution grazing experiments may underestimate phytoplankton growth coefficients and microzooplankton grazing coefficients

Study of alpha-transfer Reaction 28si( 7li,t) 32S

The 28Si( 7Li,t) 32S reaction has been studied at 48 MeV. Using a alphat potential overlap based on a microscopic cluster model, the full finite-range distorted wave Born approximation analysis was carried out for nine low-lying states; 0.0 MeV (0+), 2.23 MeV (2+), 3.78 MeV (0+), 4.46 MeV (4+), 5.01 MeV (3-), 5.80 MeV (1-), 6.76 MeV (3-), 7.43 MeV (1-) and 8.49 MeV (1-) of the residual nucleus. A re-analysis was also done for the same states of 32S having an alphad overlap for the reaction 28Si (6Li, d) 32S at 75.6 MeV. Theoretical spectroscopic factors have been calculated for the measured even-parity states of 32S using the shell model code OXBASH. The spectroscopic factors were compared for both the reactions