Analyses of celestial pole offsets with VLBI, LLR, and optical observations

This work aims to explore the possibilities of determining the long-period part of the precession-nutation of the Earth with techniques other than very long baseline interferometry (VLBI). Lunar laser ranging (LLR) is chosen for its relatively high accuracy and long period. Results of previous studies could be updated using the latest data with generally higher quality, which would also add ten years to the total time span. Historical optical data are also analyzed for their rather long time-coverage to determine whether it is possible to improve the current Earth precession-nutation model

Rare case of magnetic Ag3+^{3+} ion: double perovskite Cs2_{2}KAgF6_{6}

Normally $4d$ or $5d$ transition metals are in a low-spin state. Here using first-principles calculations, we report on a rare case of a high-spin $S$=1 magnetic state for the Ag$^{3+}$ ion in the double perovskite Cs$_{2}$KAgF$_{6}$. We also explored a possibility of a conventional low-spin $S$=0 ground state and find an associated tetragonal distortion to be 0.29 {\AA}. However, the lattice elastic energy cost and the Hund exchange loss exceed the e$_{g}$ crystal-field energy gain, thus making the low-spin tetragonal structure less favorable than the high-spin cubic structure. We conclude that the compact perovskite structure of Cs$_{2}$KAgF$_{6}$ is an important factor in stabilizing the unusual high-spin ground state of Ag$^{3+}$.Comment: 6 pages, 6 figures, accepted for publication in PR

Studies on Bone and Mineral Disorders in CKD: Determinants and Survival Implications

Disruptions in mineral metabolism occur already at an early stage of chronic kidney disease (CKD) and may eventually lead to a complex of CKD - mineral and bone disorders (CKD-MBD) characterized by alterations of the mass, turnover rate, mineralization and strength of bones, and high risk of vascular calcification, fractures and other complications resulting in worse survival. The aim of this thesis was to increase the understanding of some aspects of CKD-MBD with special emphasis on clinical and laboratory determinants and implications for clinical outcome. In Study 1, we defined and tested a novel non-surgical, adjustable model of tubulointerstitial nephropathy in mice by adding adenine to a casein-based diet and showed that this model could induce and maintain a uremic phenotype with decline of renal function and initiation of alterations linked to CKD-MBD. In Study 2, we investigated the impact of classical risk factors for osteoporosis such as age, body composition, and nutritional status in end-stage renal disease (ESRD) subjects, and how these factors influence the relationship between bone mineral density (BMD) and mortality in patients with ESRD. We found that low BMD is associated with low total fat mass, poor nutritional status and increased mortality risk in ESRD patients. In Study 3, we studied determinants of the variability of two bone metabolic markers, fibroblast growth factor-23 (FGF23) and intact parathyroid hormone (PTH) in ESRD patients treated by peritoneal dialysis, hemodialysis or online hemodiafiltration. We found that baseline vitamin D status and serum phosphorous were independent determinants of the longitudinal variation in PTH and FGF23, respectively, and that the intra-subject variability of FGF23 was lower than the variability of PTH irrespective of dialysis mode. In Study 4, we analyzed baseline serum insulin-like growth factor 1(IGF-1) concentration and the longitudinal changes of IGF-1 over 1-year in CKD stage 5 patients starting on dialysis in relation to bone and mineral metabolism parameters including BMD, nutritional status, and mortality. We found that IGF-1 associates with markers of mineral and bone metabolism and that IGF-1 is a strong independent predictor of mortality risk in CKD stage 5 patients

Quantum heat valve and entanglement in superconducting LCLC resonators

Quantum superconducting circuit with flexible coupler has been a powerful platform for designing quantum thermal machines. In this letter, we employ the tunable coupling of two superconducting resonators to realize a heat valve by modulating magnetic flux using a superconducting quantum interference device (SQUID). It is shown that a heat valve can be realized in a wide parameter range. We find a consistent relation between the heat current and quantum entanglement, which indicates the dominant role of entanglement on the heat valve. It provides an insightful understanding of quantum features in quantum heat machines.Comment: 9 figures, 4 figure