Sulphur abundances in disk stars: A correlation with silicon

We have performed new determinations of sulphur and silicon abundances for a sample of 26 disk stars based on high-resolution, high signal-to-noise spectra. The results indicate a solar [S/Fe] for [Fe/H] > −0.3, below which [S/Fe] increases to ~0.25 dex at [Fe/H] = −1.0. We find that there is a good correlation between [S/H] and [Si/H], indicating the same nucleosynthetic origin of the two elements. It seems that the ratio of sulphur to silicon does not depend on metallicity for [Fe/H] > −1.0. The implications of these results on models for the nucleosynthesis of a-capture elements and the chemical evolution of the Galaxy are discussed. Based on observations carried out at National Astronomical Observatories (Xinglong, PR China)

The lithium isotope ratio in the metal-poor halo star G271-162 from VLT/UVES observations

A high resolution (lambda /Delta lambda =~ 110 000), very high S/N (>~ 600) spectrum of the metal-poor turnoff star G 271-162 has been obtained in connection with the commissioning of UVES at VLT/Kueyen. Using both 1D hydrostatic and 3D hydrodynamical model atmospheres, the lithium isotope ratio has been estimated from the \ion{Li}{i},670.8 nm line by means of spectral synthesis. The necessary stellar line broadening (1D: macroturbulence + rotation, 3D: rotation) has been determined from unblended \ion{K}{i}, \ion{Ca}{i} and \ion{Fe}{i} lines. The 3D line profiles agree very well with the observed profiles, including the characteristic line asymmetries. Both the 1D and 3D analyses reveal a possible detection of \element[][6]{Li} in G 271-162, element [][6]{Li}/element [][7]{Li} = 0.02+/-0.01 (1sigma ). It is discussed if the smaller amount of \element[][6]{Li} in G 271-162 than in the similar halo star HD 84937 could be due to differences in stellar mass and/or metallicity or whether it may reflect an intrinsic scatter of \element[][6]{Li}/\element[][7]{Li} in the ISM at a given metallicity. Based on public data released from the UVES commissioning at the VLT/Kueyen telescope, ESO, Paranal, Chile

O/Fe in metal-poor main sequence and subgiant stars

A study of the O/Fe ratio in metal-poor main sequence and subgiant stars is presented using the \ion{O{i}},6300 Å line, the \ion{O}{i} 7774 Å triplet, and a selection of weak \ion{Fe}{ii} lines observed on high-resolution spectra acquired with the VLT UVES spectrograph. The \ion{O{i} line is detected in the spectra of 18 stars with -2.4 < [Fe/H] < -0.5, and the triplet is observed for 15 stars with Fe/H ranging from -1.0 to -2.7. The abundance analysis was made first using standard model atmospheres taking into account non-LTE effects on the triplet: the \ion{O{i}} line and the triplet give consistent results with [O/Fe] increasing quasi-linearly with decreasing [Fe/H] reaching [O/Fe] =~ +0.7 at [Fe/H] = -2.5. This trend is in reasonable agreement with other results for [O/Fe] in metal-poor dwarfs obtained using standard atmospheres and both ultraviolet and infrared OH lines. There is also broad agreement with published results for [O/Fe] for giants obtained using standard model atmospheres and the \ion{O{i}} line, and the OH infrared lines, but the \ion{O}{i} lines give higher [O/Fe] values which may, however, fall into place when non-LTE effects are considered. When hydrodynamical model atmospheres representing stellar granulation in dwarf and subgiant stars replace standard models, the [O/Fe] from the \ion{O{i}} and \ion{Fe}{ii} lines is decreased by an amount which increases with decreasing [Fe/H]. These 3D effects on [O/Fe] is compounded by the opposite behaviour of the \ion{O{i}} (continuous opacity effect) and \ion{Fe}{ii} lines (excitation effect). The [O/Fe] vs. [Fe/H] relation remains quasi-linear extending to [O/Fe] =~ +0.5 at [Fe/H] = -2.5, but with a tendency of a plateau with [O/Fe] =~ +0.3 for -2.0 < [Fe/H] < -1.0, and a hint of cosmic scatter in [O/Fe] at [Fe/H] =~ -1.0. Use of the hydrodynamical models disturbs the broad agreement between the oxygen abundances from the \ion{O{i}} , \ion{O}{i}, and OH lines, but 3D non-LTE effects may serve to erase these differences. The [O/Fe] values from the \ion{O{i}} line and the hydrodynamical model atmospheres for dwarfs and subgiant stars are lower than the values for giants using standard model atmospheres and the \ion{O{i}}, and \ion{O}{i} lines. Based on observations collected at the European Southern Observatory, Chile (ESO Nos. 65.L-0131, 65.L-0507, and 67.D-0439)

Danish Translation and Linguistic Validation of the U.S. National Cancer Institute's Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE)

Context The Common Terminology Criteria for Adverse Events (CTCAE) is the basis for standardized clinician-based grading and reporting of adverse events in cancer clinical trials. The U.S. National Cancer Institute has developed the Patient-Reported Outcomes version of the CTCAE (PRO-CTCAE) to incorporate patient self-reporting of symptomatic adverse events. Objectives The aim of the study was to translate and linguistically validate a Danish language version of PRO-CTCAE. Methods The U.S. English language PRO-CTCAE was translated into Danish using forward and backward procedures with reconciliation. The linguistic validity of the PRO-CTCAE Danish was examined in two successive rounds of semistructured cognitive interviews in a sample of 56 patients equally distributed by gender and cancer type (prostate, head and neck, lung, breast, gynecological, gastrointestinal, and hematological cancer), and who were currently undergoing cancer treatment. Results In the first round of linguistic validation (n = 42), the phrasing of five symptomatic toxicities was adjusted, and the refined phrasing was retested in a second round of interviews (n = 14). Agreement about phrasing that was both culturally acceptable and semantically comprehensible was achieved in the second round. Statements from participants describing the meaning of the PRO-CTCAE symptomatic toxicities support conceptual equivalence to the U.S. English language version. Conclusion Availability of the NCI PRO-CTCAE in languages beyond English will support international congruence in self-reporting of side effects of cancer treatment. A rigorous methodology was used to develop the Danish language version of PRO-CTCAE. Results provide preliminary support for the use of PRO-CTCAE in cancer clinical trials that include Danish speakers

Feasibility and acceptability of electronic symptom surveillance with clinician feedback using the patient-reported outcomes version of common terminology criteria for adverse events (PRO-CTCAE) in Danish prostate cancer patients

Background: The aim was to examine the feasibility, acceptability and clinical utility of electronic symptom surveillance with clinician feedback using a subset of items drawn from the Patient-Reported Outcomes version of Common Terminology Criteria for Adverse Events (PRO-CTCAE) in a cancer treatment setting. Methods: Danish-speaking men with castration-resistant metastatic prostate cancer receiving treatment at the Department of Oncology, Rigshospitalet, Copenhagen between March 9, 2015 and June 8, 2015 were invited to participate (n = 63 eligible). Participants completed the PRO-CTCAE questionnaire on tablet computers using AmbuFlex software at each treatment visit in the outpatient clinic. In total, 22 symptomatic toxicities (41 PRO-CTCAE items), corresponding to the symptomatic adverse-events profile associated with the regimens commonly used for prostate cancer treatment (Docetaxel, Cabazitaxel, Abiraterone, Alpharadin), were selected. Participants’ PRO-CTCAE responses were presented graphically to their treating oncologists via an AmbuFlex dashboard, for real-time use to enhance the patient-clinician dialogue that occurs during the consultation prior to each treatment cycle. Technical and clinical barriers and acceptability were evaluated through semi-structured interviews with both patients and oncologists. Patients receiving active treatment at the end of the study period completed an evaluation questionnaire. Results: Fifty-four out of sixty-three (86%) eligible patients were enrolled. The PRO-CTCAE questionnaire was completed a total of 168 times by 54 participants (median number per patient was 3, range 1–5). Eight surveys were missed, resulting in a compliance rate of 97%. At the end of the study period, 35 patients (65%) were still receiving active treatment and completed the evaluation questionnaire. Patients reported that their PRO-CTCAE responses served as a communication tool. Oncologists stated that the availability of the PRO-CTCAE self-reports during the consultation improved patient-clinician communication about side effects. Conclusion: Electronic capture of symptomatic toxicities using PRO-CTCAE and the submission of self-reports to clinicians prior to consultation were feasible among metastatic prostate cancer patients receiving chemotherapy in an outpatient setting, and this procedure was acceptable to both patients and clinicians. Continued research, including a cluster-randomized trial, will evaluate the effects of submitting patients’ PRO-CTCAE results to clinicians prior to consultation on the quality of side-effects management and resultant clinical outcomes

Best practices for addressing missing data through multiple imputation

A common challenge in developmental research is the amount of incomplete and missing data that occurs from respondents failing to complete tasks or questionnaires, as well as from disengaging from the study (i.e., attrition). This missingness can lead to biases in parameter estimates and, hence, in the interpretation of findings. These biases can be addressed through statistical techniques that adjust for missing data, such as multiple imputation. Although multiple imputation is highly effective, it has not been widely adopted by developmental scientists given barriers such as lack of training or misconceptions about imputation methods. Utilizing default methods within statistical software programs like listwise deletion is common but may introduce additional bias. This manuscript is intended to provide practical guidelines for developmental researchers to follow when examining their data for missingness, making decisions about how to handle that missingness and reporting the extent of missing data biases and specific multiple imputation procedures in publications

Oxygen abundances in metal-poor subgiants as determined from [O I], O I and OH lines

Original article can be found at: http://www.aanda.org/--Copyright The European Southern Observatory (ESO) DOI : 10.1051/0004-6361:20053181Peer reviewe

The most metal-poor damped Lyα systems: insights into chemical evolution in the very metal-poor regime

We present a high spectral resolution survey of the most metal-poor damped Lyα absorption systems (DLAs) aimed at probing the nature and nucleosynthesis of the earliest generations of stars. Our survey comprises 22 systems with iron abundance less than 1/100 solar; observations of seven of these are reported here for the first time. Together with recent measures of the abundances of C and O in Galactic metal-poor stars, we reinvestigate the trend of C/O in the very metal-poor (VMP) regime and we compare, for the first time, the O/Fe ratios in the most metal-poor DLAs and in halo stars. We confirm the near-solar values of C/O in DLAs at the lowest metallicities probed, and find that their distribution is in agreement with that seen in Galactic halo stars. We find that the O/Fe ratio in VMP DLAs is essentially constant, and shows very little dispersion, with a mean [〈O/Fe〉]=+0.39 ± 0.12, in good agreement with the values measured in Galactic halo stars when the oxygen abundance is measured from the [O I] λ6300 line. We speculate that such good agreement in the observed abundance trends points to a universal origin for these metals. In view of this agreement, we construct the abundance pattern for a typical VMP DLA and compare it to model calculations of Population II and Population III nucleosynthesis to determine the origin of the metals in VMP DLAs. Our results suggest that the most metal-poor DLAs may have been enriched by a generation of metal-free stars; however, given that abundance measurements are currently available for only a few elements, we cannot yet rule out an additional contribution from Population II stars