Comparing foreground removal techniques for recovery of the LOFAR-EoR 21 cm power spectrum

ABSTRACT We compare various foreground removal techniques that are being utilized to remove bright foregrounds in various experiments aiming to detect the redshifted 21 cm signal of neutral hydrogen from the epoch of reionization. In this work, we test the performance of removal techniques (FastICA, GMCA, and GPR) on 10 nights of LOFAR data and investigate the possibility of recovering the latest upper limit on the 21 cm signal. Interestingly, we find that GMCA and FastICA reproduce the most recent 2σ upper limit of $\Delta ^2_{21} \lt $ (73)2 mK2 at k = 0.075 hcMpc−1, which resulted from the application of GPR. We also find that FastICA and GMCA begin to deviate from the noise-limit at k-scales larger than ∼0.1 hcMpc−1. We then replicate the data via simulations to see the source of FastICA and GMCA’s limitations, by testing them against various instrumental effects. We find that no single instrumental effect, such as primary beam effects or mode-mixing, can explain the poorer recovery by FastICA and GMCA at larger k-scales. We then test scale-independence of FastICA and GMCA, and find that lower k-scales can be modelled by a smaller number of independent components. For larger scales (k ≳ 0.1 hcMpc−1), more independent components are needed to fit the foregrounds. We conclude that, the current usage of GPR by the LOFAR collaboration is the appropriate removal technique. It is both robust and less prone to overfitting, with future improvements to GPR’s fitting optimization to yield deeper limits.

The effects of shungite on somatoform disorders in athletes

The article demonstrates the importance of the application of new biomedical technologies in the correction of somatoform disorders in athletes. In observation were 86 athletes playing sports. Comprehensive clinical, psychological and instrumental examination showed that 11, 3% of them have some somatic pathology, but the complaint didn’t match up to this pathology, she had overdone character. Moreover, in this group in 36.4% of cases, there are previous histories of acute infectious diseases. The athletes were divided into two equal groups (main and control) by 43 people. In the main group, the athletes were treated orally with shungite in the form of tablets, in the control group - the psycho-pharmacotherapy. The same clinical and instrumental effect was observed in both groups. In the control group the undesirable effect of reducing muscle tone, drowsiness was detected. This allowed the authors to consider that it is expedient to use shungite for the correction of sym-tomatics in athletes with somatoform disorders.

Comparative rainfall data analysis from two vertically pointing radars, an optical disdrometer, and a rain gauge

The authors present results of a comparative analysis of rainfall data from several ground-based instruments. The instruments include two vertically pointing Doppler radars, S-band and X-band, an optical disdrometer, and a tipping-bucket rain gauge. All instruments were collocated at the Iowa City Municipal Airport in Iowa City, Iowa, for a period of several months. The authors used the rainfall data derived from the four instruments to first study the temporal variability and scaling characteristics of rainfall and subsequently assess the instrumental effects on these derived properties. The results revealed obvious correspondence between the ground and remote sensors, which indicates the significance of the instrumental effect on the derived properties.

VI. (Re)Evaluations – (Why) Do Reception Studies Matter?

There has been a paradox at the centre of much of the discussion in this book. On the one hand much of the material analysed and the issues raised have been shown to be central to public, artistic, political and cultural processes. In some cases (e.g. chapter 3) there has been direct tension between appropriation of classical referents for political or social purposes and the demands of the independence and integrity of scholarship. Related tensions may also arise when appropriation has commercial rationales. Educational appropriation, too, is selective and may have a strongly instrumental focus. On the other hand, I have urged caution in the face of the idea that the arts have a decisive function as shapers or transformers of consciousness although they are a constituent part of broader social and cultural fabrics. Accordingly, I have suggested that there are necessary distinctions to be made between the heightening of sensitivity or awareness on the part of individuals or groups who ‘receive’ and the translations of this awareness into considered action (whether personal, social or political). I have tried to show that any kind of appropriation for instrumental effect is necessarily two-edged and needs to be subject to the kind of scrutiny which identifies both commonalities and differences between the source text and the refigured text and which subjects both to contextual analysis and to investigation of the silences and marginalia embedded within them.