Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

The WGARG was created in 2001 to oversee the rapid growth of the quantitative determination and understanding of the abundance patterns seen in red-giant stars. As the field progresses we are regularly reminded of how broad and multi-disciplinary is this area of research.

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Gas-accepting ion sources for radiocarbon accelerator mass spectrometry (AMS) have permitted the direct analysis of CO2 gas, eliminating the need to graphitize samples. As a result, a variety of analytical instruments can be interfaced to an AMS system, processing time is decreased, and smaller samples can be analyzed (albeit with lower precision). We have coupled a gas chromatograph to a compact 14C AMS system fitted with a microwave ion source for real-time compound-specific 14C analysis. As an initial test of the system, we have analyzed a sample of fatty acid methyl esters and biodiesel. Peak shape and memory was better then existing systems fitted with a hybrid ion source while precision was comparable. 14C/12C ratios of individual components at natural abundance levels were consistent with those determined by conventional methods. Continuing refinements to the ion source are expected to improve the performance and scope of the instrument.

The classical time series decomposition method was used to compare the temporal pattern of rabies in Chile before and after the implementation of the control programme. In the years 1950–60, a period without control measures, rabies showed an increasing trend, a seasonal excess of cases in November and December and a cyclic behaviour with outbreaks occurring every 5 years. During 1961–1970 and 1971–86, a 26-year period that includes two different phases of the rabies programme which started in 1961, there was a general decline in the incidence of rabies. The seasonality disappeared when the disease reached a low frequency level and the cyclical component was not evident.

In the context of a general survey on the thermoelectric potential of cationic clathrates, formation, crystal chemistry and physical properties were investigated for novel inverse clathrates deriving from Sn19.3Cu4.7P22I8. Substitution of Cu by Zn and Sn by Ni was attempted to bring down electrical resistivity and lower thermal conductivity. Materials were synthesized by mechanical alloying using a ball mill and hot pressing. Structural investigations for all specimens confirm isotypism with the cubic primitive clathrate type I structure (lattice parameters a = ˜1.1 nm and space group type Pm-3n). Studies of transport properties evidence holes as the majority charge carriers. Thermal expansion data, measured in a capacitance dilatometer from 4 to 300 K on Sn19.3Cu1.7Zn3P19.92.1I8, compare well with literature data available for Sn24P19.62.4Br8 and for an anionic type I clathrate Ba8Zn8Ge38. From the rather complex crystal structure including split atom sites and lattice defects thermal conductivity in inverse clathrates is generally low. Following Zintl rules rather closely inverse clathrates tend to be semiconductors with attractive Seebeck coefficients. Thus for thermoelectric applications the main activity will have to focus on achieving low electrical resistivity in a compromise with still sufficiently high Seebeck coefficients.

The main activity of the WG on Abundances in Red Giants has been to propose a JD for the IAU GA in 2009. The increasing evidence for distinct populations within globular clusters is leading to the view that there is a continuum between globular clusters and the smallest of the galaxies. Our JD was designed to investigate this link. However, our JD was incorporated into IAU Symposium No. 266 Star Clusters: Basic Building Blocks throughout Time and Space for the IAU XXVII in Rio de Janeiro, 2009. We will be responsible for organising one session in the Symposium to cover the agenda put forward in our JD proposal.

Chronic elevations of endogenous cortisol levels have been shown to alter medial temporal cortical structures and to be accompanied by declarative memory impairments and depressive symptoms in human adults. These effects of elevated endogenous levels of cortisol have not been directly studied in adolescents. Because adolescents with Cushing syndrome show endogenous elevations in cortisol, they represent a unique natural model to study the effects of prolonged hypercortisolemia on brain function, and memory and affective processes during this developmental stage. Using functional magnetic resonance imaging (fMRI), we compared 12 adolescents with Cushing syndrome with 22 healthy control adolescents on amygdala and anterior hippocampus activation during an emotional faces encoding task. None of these adolescents manifested depressive symptoms. Encoding success was assessed using a memory recognition test performed after the scan. The fMRI analyses followed an event-related design and were conducted using the SPM99 platform. Compared to healthy adolescents, patients with Cushing syndrome showed greater left amygdala and right anterior hippocampus activation during successful face encoding. Memory performance for faces recognition did not differ between groups. This first study of cerebral function in adolescents with chronic endogeneous hypercortisolemia due to Cushing syndrome demonstrates the presence of functional alterations in amygdala and hippocampus, which are not associated with affective or memory impairments. Such findings need to be followed by work examining the role of age and related brain maturational stage on these effects, as well as the identification of possible protective factors conferring resilience to affective and cognitive consequences in this disease and/or during this stage of cerebral development.