Nucleosynthesis in Type I X-ray Bursts

Type I X-ray bursts are thermonuclear explosions that occur in the envelopes of accreting neutron stars. Detailed observations of these phenomena have prompted numerous studies in theoretical astrophysics and experimental nuclear physics since their discovery over 35 years ago. In this review, we begin by discussing key observational features of these phenomena that may be sensitive to the particular patterns of nucleosynthesis from the associated thermonuclear burning. We then summarize efforts to model type I X-ray bursts, with emphasis on determining the nuclear physics processes involved throughout these bursts. We discuss and evaluate limitations in the models, particularly with regard to key uncertainties in the nuclear physics input. Finally, we examine recent, relevant experimental measurements and outline future prospects to improve our understanding of these unique environments from observational, theoretical and experimental perspectives.Comment: Accepted by Prog. Part. Nucl. Phys., 45 pages, 14 figure

High-j single-particle neutron states outside the N=82 core

The behaviour of the i13/2 and h9/2 single-neutron strength was studied with the (4He,3He) reaction on 138Ba, 140Ce, 142Nd and 144Sm targets at a beam energy of 51 MeV. The separation between the single-neutron states i13/2 and h9/2 was measured in N =83 nuclei with changing proton number. To this end spectroscopic factors for states populated in high-l transfer were extracted from the data. Some mixing of l=5 and 6 strength was observed with states that are formed by coupling the f7/2 state to the 2+ and 3- vibrational states and the mixing matrix elements were found to be remarkably constant. The centroids of the strength indicate a systematic change in the energies of the i13/2 and h9/2 single-neutron states with increasing proton number that is in quantitative agreement with the effects expected from the tensor interaction.Comment: 12 pages of text, 3 diagram

Underlying symmetries of realistic interactions and the nuclear many-body problem

The present study brings forward important information, within the framework of spectral distribution theory, about the types of forces that dominate three realistic interactions, CD-Bonn, CDBonn+ 3terms and GXPF1, in nuclei and their ability to account for many-particle effects such as the formation of correlated nucleon pairs and enhanced quadrupole collective modes. Like-particle and proton-neutron isovector pairing correlations are described microscopically by a model interaction with Sp(4) dynamical symmetry, which is extended to include an additional quadrupole-quadrupole interaction. The analysis of the results for the 1f7/2 level shows that both CD-Bonn+3terms and GXPF1 exhibit a well-developed pairing character compared to CD-Bonn, while the latter appears to build up more (less) rotational isovector T = 1 (isoscalar T = 0) collective features. Furthermore, the three realistic interactions are in general found to correlate strongly with the pairing+quadrupole model interaction, especially for the highest possible isospin group of states where the model interaction can be used to provide a reasonable description of the corresponding energy spectra.Comment: 12 pages, 4 figure

Effect of diuretics on sodium, potassium and chloride levels- a cross sectional study

Background: Diuretics are one of the widely used class of drugs used in various cardiovascular and other disorders. However, they can cause various metabolic adverse effects, electrolyte imbalance being among important changes.Methods: A cross sectional study was conducted in which patients diagnosed with hypertension for at least one month were included. Over a period of 6 months patients were enrolled irrespective of whether they were taking diuretics or not. Demographic details, drug therapy and electrolyte levels were recorded in a proforma. Data was analyzed for difference in serum electrolyte levels between diuretic and nondiuretic groups as well as between different diuretic groups.Results: Out of total 177 participants, 71 were on diuretic therapy. There was significant difference in mean serum sodium (S. Na), potassium (S. K) and chlorine (S. Cl) levels between diuretic and nondiuretic groups (P<0.05). Hyponatremia, hypokalemia and hyperkalemia were observed. Thiazide diuretic group showed significantly greater hyponatremia compared to other diuretics (P=0.028). Hyperkalemia was observed in participants receiving K sparing diuretic or combination of loop and K sparing diuretics. Old age and number of comorbidities showed negative association with S. Na. Females had significantly more hyponatremia than male participants.Conclusions: The study confirms that diuretics cause various abnormalities in electrolytes namely Na and K levels. Old age, comorbidities and female sex are risk factors for hyponatremia