3 research outputs found
Systematic investigation of quadrupole properties in deformed and transitional nuclei
In the present work, we address a long-standing problem in nuclear physics on
how to decipher the nature of collective motion from electromagnetic transition
probabilities. A systematic analysis of the transitions is performed
for thirty nuclei using the triaxial projected shell model (TPSM) approach. It
is shown that transitions for the -bands depict a
staggering phase and this phase reverses with the inclusion of the
quasiparticle excitations for all the nuclei, except for the six nuclei of
Ge, Ru, Er, Os, Pt and Th. This
feature is analogous to the energy staggering phase obtained for these nuclei.
It is noted that the energy staggering phase with even-spin-down
(odd-spin-down), which is considered as a signature of -softness
(-rigidity), corresponds to even-spin-up (odd-spin-up) staggering phase
of the transitions. Further, TPSM predicted values for both energies
and transition are shown to be in good agreement with the corresponding
experimental values.Comment: 24 pages, 28 figure
Triaxial projected shell model approach for negative parity states in even-even nuclei
The triaxial projected shell model (TPSM) approach is generalized to
investigate the negative parity band structures in even-even systems. In the
earlier version of the TPSM approach, the quasiparticle excitations were
restricted to one major oscillator shell and it was possible to study only
positive parity states in even-even systems. In the present extension, the
excited quasiparticles are allowed to occupy two major oscillator shells, which
makes it possible to generate the negative parity states. As a major
application of this development, the extended approach is applied to elucidate
the negative parity high-spin band structures in Ru and it is shown
that energies obtained with neutron excitation are slightly lower than the
energies calculated with proton excitation. However, the calculated aligned
angular momentum () clearly separates the two spectra with neutron
in reasonable agreement with the empirically evaluated from the
experimental data, whereas proton shows large deviations. Furthermore, we
have also deduced the transition quadrupole moments from the TPSM wavefunctions
along the negative-parity yrast- and yrare- bands and it is shown that these
quantities exhibit rapid changes in the bandcrossing region.Comment: 14 pages, 17 figure
Clinical Characterization and Genomic Analysis of Samples from COVID-19 Breakthrough Infections during the Second Wave among the Various States of India
From March to June 2021, India experienced a deadly second wave of COVID-19, with an increased number of post-vaccination breakthrough infections reported across the country. To understand the possible reason for these breakthroughs, we collected 677 clinical samples (throat swab/nasal swabs) of individuals from 17 states/Union Territories of the country who had received two doses (n = 592) and one dose (n = 85) of vaccines and tested positive for COVID-19. These cases were telephonically interviewed and clinical data were analyzed. A total of 511 SARS-CoV-2 genomes were recovered with genome coverage of higher than 98% from both groups. Analysis of both groups determined that 86.69% (n = 443) of them belonged to the Delta variant, along with Alpha, Kappa, Delta AY.1, and Delta AY.2. The Delta variant clustered into four distinct sub-lineages. Sub-lineage I had mutations in ORF1ab A1306S, P2046L, P2287S, V2930L, T3255I, T3446A, G5063S, P5401L, and A6319V, and in N G215C; Sub-lineage II had mutations in ORF1ab P309L, A3209V, V3718A, G5063S, P5401L, and ORF7a L116F; Sub-lineage III had mutations in ORF1ab A3209V, V3718A, T3750I, G5063S, and P5401L and in spike A222V; Sub-lineage IV had mutations in ORF1ab P309L, D2980N, and F3138S and spike K77T. This study indicates that majority of the breakthrough COVID-19 clinical cases were infected with the Delta variant, and only 9.8% cases required hospitalization, while fatality was observed in only 0.4% cases. This clearly suggests that the vaccination does provide reduction in hospital admission and mortality