Abundances main results

5 Abundances main results 3.5.1 Solar and local Galactic abundances 

9 Equilibrium (i.e. local steady-state) ionization leads in this regime to solar-corona-like conditions where col-lisional ionization is balanced by recombination and the degree of ionization is fixed by the temperature alone, the electron density cancelling out. However, here departures from equilibrium occur because the time taken to establish ionization equilibrium is not negligible with respect to the timescale of expansion. 

Element Photospheric Meteoritic Element Photospheric Meteoritic 

Terrestrial isotope ratios are mainly unaffected by these processes and therefore provide valid information about standard abundances of individual nuclear species except in special cases where they have been modified by fractionation (e.g. D/H), differential escape from the atmosphere or radioactive decay, e.g. 40Ar is enhanced in the atmosphere relative to 36Ar by 40K decay and there is extra 136Xe thought to result from fission of 244Pu. 

CI1 meteorites provide a particularly good match to solar, and are used to fill in the gaps left by unknown or inaccurate photospheric abundances as the latter have improved over the years, the agreement with CI1 (except in the special 

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We have determined the iron abundances for a sub-sample of stars 13 Galactic, 13 LMC and 12 SMC Cepheids. Our main result is summarised in the Fig.l, where we plot the V-band residuals 5(My) of our stars from the standard PL relation of [3] as a function of the iron abundance we have derived from the... 

Hydrogen is burnt to 4He via the CNO cycles, but the Ne-Na and Mg-Al chains also operate. The main result from the CNO cycle, besides the conversion of H to He, is an increase in the abundances of 13C and 14N from the destruction of other CNO species. The isotopes 12C and 15N are first destroyed by the CN cycle, which comes into equilibrium quickly. Later, the oxygen isotopes 160 and lsO are also destroyed to produce 14N. The abundance of 170 can be enhanced by the CNO cycle, depending on the uncertain rate of the 17O + p branching reactions. The H-shell ashes are important because they affect the nucleosynthesis that occurs in the He-shell. 

The histopathological features of PM may be radically different from those of JDM and ADM. There is little, if any, evidence of involvement of the micro vasculature and the muscle necrosis which occurs appears to be the direct result of targeting of individual muscle fibers. In the dermatomyositis syndromes, antibody-dependent humoral mechanisms are predominant and B-lymphocytes are seen to be the most abundant cell type in almost all JDM cases and a substantial proportion of ADM cases. In contrast, most muscle biopsies from PM patients show evidence of inflammation in which TS (cytotoxic) lymphocytes predominate (Figure 20). Moreover, the distribution of inflammatory cell infiltrates tends to be different. Instead of the mainly perifascicular location of lymphocytes in JDM/ADM, there... 

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