We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60$\to$–70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.

Synchrotron-based X-ray techniques are used increasingly to characterize actinide element speciation in heterogeneous media related to nuclear waste disposal safety. Especially techniques offering added temporal, spatial and energy resolved information are advancing our understanding of f-element physics and chemistry in general and of actinide element waste disposal in particular. Examples of investigations of uranium containing systems using both highly (energy) resolved X-ray emission spectroscopy (HRXES) techniques and spatially resolved techniques with focused X-ray beams are presented in this paper: polarization dependent partial fluorescence yield X-ray absorption near edge structure (PD-PFY-XANES) spectroscopic studies of a single Cs2UO2Cl4 crystal, which experimentally reveal a splitting of the σ, π, and δ components of the 6d valence states [1], and characterization of UO2/Mo thin films prepared on different substrates using a combination of techniques (2D and 3D micro- and nano-X-ray fluorescence, XANES and both holographic and ptychographic tomography).

Faecal microbial changes associated with ageing include reduced bifidobacteria numbers. These changes coincide with an increased risk of disease development. Prebiotics have been observed to increase bifidobacteria numbers within humans. The present study aimed to determine if prebiotic galacto-oligosaccharides (GOS) could benefit a population of men and women of 50 years and above, through modulation of faecal microbiota, fermentation characteristics and faecal water genotoxicity. A total of thirty-seven volunteers completed this randomised, double-blind, placebo-controlled crossover trial. The treatments – juice containing 4 g GOS and placebo – were consumed twice daily for 3 weeks, preceded by 3-week washout periods. To study the effect of GOS on different large bowel regions, three-stage continuous culture systems were conducted in parallel using faecal inocula from three volunteers. Faecal samples were microbially enumerated by quantitative PCR. In vivo, following GOS intervention, bifidobacteria were significantly more compared to post-placebo (P = 0·02). Accordingly, GOS supplementation had a bifidogenic effect in all in vitro system vessels. Furthermore, in vessel 1 (similar to the proximal colon), GOS fermentation led to more lactobacilli and increased butyrate. No changes in faecal water genotoxicity were observed. To conclude, GOS supplementation significantly increased bifidobacteria numbers in vivo and in vitro. Increased butyrate production and elevated bifidobacteria numbers may constitute beneficial modulation of the gut microbiota in a maturing population.

A technology platform is described for the integration of low-loss inductors, capacitors, and MEMS capacitors on a high-resistivity Si substrate. Using this platform the board space area taken up by e.g. a DCS PA output impedance matching circuit can be reduced by 50%. The losses of passive components that are induced by the semi-conducting Si substrate can effectively be suppressed using a combination of surface amorphisation and the use of poly crystalline Si substrates. A MEM switchable capacitor with a capacitance switching factor of 40 and an actuation voltage of 5V is demonstrated. A continuous tuneable dual-gap capacitor is demonstrated with a tuning ratio of 9 using actuation voltages below 15V.

Objective: We studied the influence of the methodologic quality of individual trials on the outcome of a landmark meta-analysis on thrombolytic therapy in acute myocardial infarction. From each study we extracted the number of patients in both groups who died in hospital or during follow-up. Methodologic quality was assessed using the Delphi list. We first recalculated pooled odds ratios (ORs) and 95% confidence intervals (CIs), on the studies found and compared them with the original results of Yusuf et al. Next we incorporated the results of quality assessment in five different ways in the calculation of the pooled ORs: a) component analysis; b) visual plot; c) quality score as a threshold score; d) quality score as a weighting factor; and e) cumulative pooling.

Results and Conclusion: No correlation between quality scores and ORs was found. Studies with a proper description of the different quality components provided an estimate close to the true treatment effect. No major differences were found between the results of the five different methods of incorporating the quality scores into the final conclusion.

The last decades have shown a rapid increase in nonresponse rates. For this reason it is important to study nonresponse and think about it critically. In this article we investigated whether nonresponse affected estimates of the levels of adjustment problems in children and the correlations between these outcomes. The nonresponse was caused by parents who refused permission to interview their children at school, parents who did not return a questionnaire, teachers who did not complete the questionnaire, and parents who refused to participate in an in-depth study, with nonresponse rates of 9%, 69%, 25%, and 46% respectively. The sample consisted of 1282 children aged 4–5 years and the dependent measures were peer-rated sociometric status, self-rated wellbeing at school, and teacher-rated behaviour problems. Despite considerable nonresponse in some conditions our results showed hardly any evidence for bias. This suggested that bias cannot simply be inferred from the amount of nonresponse and that standard rules such as ‘‘nonresponse rates higher than 50% are not acceptable’’ lack a scientific basis. Instead, we argue that to assess nonresponse bias the specific conditions and analyses of the study will need to be considered and special measures may be required.

Objective: This study investigates the influence of different aspects of methodologic quality on the conclusions of a systematic review concerning treatments of acute lateral ankle sprain.

Method: A data set of a systematic review of 44 trials was used, of which 22 trials could be included in this study. Quality assessment of the individual studies was performed using the Delphi list. We calculated effect sizes of the main outcome measure in each study in order to evaluate the relationship between overall quality scores and outcome. Next, we investigated the impact of design attributes on pooled effect sizes by subgroup analysis.

Results: The quality of most studies (82%) was low; only 4 of 22 trials were of high quality. Studies with proper randomization and blinding procedure produce a slightly higher (not statistically significant) effect estimate compared to the other studies.

Conclusion: Previous research has suggested that methodologically poorly designed studies tend to over-estimate the effect estimate. Our study does not confirm these conclusions.

Thirty five grants were made during the triennium October 1, 1996 to September 30, 1999. The astronomer, home country, and host country are listed below.

The present account refers mainly to research work published in the period 1973–1975. Due to the limited space available, and the rapidly increasing number of contributions in the field of Commission. 28, it has not been possible to write an all-inclusive report. As in the previous IAU volumes, the report is not intended as a repetition of the summaries given in the Astronomy and Astrophysics Abstracts. In stressing the importance of certain areas of research, the personal views of the writer(s) cannot be entirely avoided.