Photon Redshift in a Magnetic field

Previous results from the authors concerning the arising a tiny photon anomalous paramagnetic moment are also interpreted as a red-shift in analogy to the gravitational known effect. It is due to the photon interaction with the magnetized virtual electron-positron background which withdraw transverse momentum from photons and is polarization-dependent. If the photon frequency red-shift implies a change in time, a clock would go faster for increasing magnetic field intensity

Carbon and oxygen in HII regions of the Magellanic Clouds: abundance discrepancy and chemical evolution

We present C and O abundances in the Magellanic Clouds derived from deep spectra of HII regions. The data have been taken with the Ultraviolet-Visual Echelle Spectrograph at the 8.2-m VLT. The sample comprises 5 HII regions in the Large Magellanic Cloud (LMC) and 4 in the Small Magellanic Cloud (SMC). We measure pure recombination lines (RLs) of CII and OII in all the objects, permitting to derive the abundance discrepancy factors (ADFs) for O^2+, as well as their O/H, C/H and C/O ratios. We compare the ADFs with those of other HII regions in different galaxies. The results suggest a possible metallicity dependence of the ADF for the low-metallicity objects, but more uncertain for high-metallicity objects. We compare nebular and B-type stellar abundances and we find that the stellar abundances agree better with the nebular ones derived from collisionally excited lines (CELs). Comparing these results with other galaxies we observe that stellar abundances seem to agree better with the nebular ones derived from CELs in low-metallicity environments and from RLs in high-metallicity environments. The C/H, O/H and C/O ratios show almost flat radial gradients, in contrast with the spiral galaxies where such gradients are negative. We explore the chemical evolution analysing C/O vs. O/H and comparing with the results of HII regions in other galaxies. The LMC seems to show a similar chemical evolution to the external zones of small spiral galaxies and the SMC behaves as a typical star-forming dwarf galaxy.Comment: Accepted for publication in MNRAS, 17 pages, 11 figures, 8 table

The Iron abundance in Galactic Planetary Nebulae

We constrain the iron abundance in a sample of 33 low-ionization Galactic planetary nebulae (PNe) using [Fe III] lines and correcting for the contribution of higher ionization states with ionization correction factors (ICFs) that take into account uncertainties in the atomic data. We find very low iron abundances in all the objects, suggesting that more than 90% of their iron atoms are condensed onto dust grains. This number is based on the solar iron abundance and implies a lower limit on the dust-to-gas mass ratio, due solely to iron, of M_dust/M_gas>1.3x10^{-3} for our sample. The depletion factors of different PNe cover about two orders of magnitude, probably reflecting differences in the formation, growth, or destruction of their dust grains. However, we do not find any systematic difference between the gaseous iron abundances calculated for C-rich and O-rich PNe, suggesting similar iron depletion efficiencies in both environments. The iron abundances of our sample PNe are similar to those derived following the same procedure for a group of 10 Galactic H II regions. These high depletion factors argue for high depletion efficiencies of refractory elements onto dust grains both in molecular clouds and AGB stars, and low dust destruction efficiencies both in interstellar and circumstellar ionized gas.Comment: Accepted for publication in ApJ. 15 pages, 4 Postscript figures, corrected typos, Tables 2 and 3 correcte

Economic evaluation of sunitinib versus pazopanib and best supportive care for the treatment of metastatic renal cell carcinoma in Chile: cost-effectiveness analysis and a mixed treatment comparison

© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. Background: Sunitinib and Pazopanib are two metastatic renal cell carcinoma (MRCC) treatment alternatives, however the health system in Chile does not consider coverage for any. The cost-effectiveness versus relevant comparator was assessed to support evidence-based decision making. Methods: A four health states Markov model was built: first, second line treatments, BSC and death. Benefits were measured in QALYs, and efficacy estimates were obtained from an indirect treatment comparison. A 10-year time horizon and a 3% undifferentiated discount rate were considered. Deterministic and probabilistic sensitivity analyses were performed. Results: The costs of treating MRCC with Sunitinib were higher than Pazopanib and BSC. When comparing Sunitinib versus Pazopanib, the incremental benefit is small favoring Sunitinib (0.03 QALYs). The base case scenario shows an average ICER of PA versus BSC of US$62,327.11/QALY and of US$85,885/QALY for Sunitinib versus Pazopanib. The ICER was most sensitive to the OS relative to BSC, where evidence was associated to important bias. Conclusions: Sunitinib or Pazopanib can be considered cost-effective if a 3 GDP per-capita threshold is assumed. The decision between SU or PA is highly sensitive to the price of the drugs, rather than the outcomes. Therefore, the decision might be made based on cost-minimization exercise