Foreground removal from WMAP 5yr temperature maps using an MLP neural network

One of the main obstacles for extracting the cosmic microwave background (CMB) signal from observations in the mm/sub-mm range is the foreground contamination by emission from Galactic component: mainly synchrotron, free-free, and thermal dust emission. The statistical nature of the intrinsic CMB signal makes it essential to minimize the systematic errors in the CMB temperature determinations. The feasibility of using simple neural networks to extract the CMB signal from detailed simulated data has already been demonstrated. Here, simple neural networks are applied to the WMAP 5yr temperature data without using any auxiliary data. A simple \emph{multilayer perceptron} neural network with two hidden layers provides temperature estimates over more than 75 per cent of the sky with random errors significantly below those previously extracted from these data. Also, the systematic errors, i.e.\ errors correlated with the Galactic foregrounds, are very small. With these results the neural network method is well prepared for dealing with the high - quality CMB data from the ESA Planck Surveyor satellite.Comment: 6 pages, 13 figure

Confirmation of the detection of B-modes in the Planck polarization maps

One of the main problems for extracting the Cosmic Microwave Background (CMB) from submm/mm observations is to correct for the Galactic components, mainly synchrotron, free - free and thermal dust emission with the required accuracy. Through a series of papers, it has been demonstrated that this task can be fulfilled by means of simple neural networks with high confidence. The main purpose of this paper is to demonstrate that the CMB BB power spectrum detected in the Planck 2015 polarization maps is present in the improved Planck 2017 maps with higher signal-to-noise ratio. Two features have been detected in the EB power spectrum in the new data set, both with S/N $\sim$4 . The origin of these features is most likely leakage from E to B with a level of about 1 per cent. This leakage gives no significant contribution to the detected BB power spectrum. The TB power spectrum is consistent with a zero signal. Altogether, the BB power spectrum is not consistent with the 'canonical' tensor-to-scalar models combined with gravitational lensing spectra. These results will give additional strong arguments for support to the proposed polarization satellite projects to follow up on the Planck mission .Comment: accepted for puplication in Astronomical Note

Excess B-modes extracted from the Planck polarization maps

One of the main obstacles for extracting the Cosmic Microwave Background (CMB) from mm/submm observations is the pollution from the main Galactic components: synchrotron, free-free and thermal dust emission. The feasibility of using simple neural networks to extract CMB has been demonstrated on both temperature and polarization data obtained by the WMAP satellite. The main goal of this paper is to demonstrate the feasibility of neural networks for extracting the CMB signal from the Planck polarization data with high precision. Both auto-correlation and cross-correlation power spectra within a mask covering about 63 percent of the sky have been used together with a 'high pass filter' in order to minimize the influence of the remaining systematic errors in the Planck Q and U maps. Using the Planck 2015 released polarization maps, a BB power spectrum have been extracted by \textit{Multilayer Perceptron} neural networks. This spectrum contains a bright feature with signal to noise ratios $\simeq$ 4.5 within 200 $\leq$ l $\leq$ 250. The spectrum is significantly brighter than the BICEP2 2015 spectrum, with a spectral behaviour quite different from the 'canonical' models (weak lensing plus B-modes spectra with different tensor to scalar ratios). The feasibility of the neural network to remove the residual systematics from the available Planck polarization data to a high level has been demonstrated.Comment: paper accepted for publication in Astronomical Note

Foreground removal from WMAP 7yr polarization maps using an MLP neural network

One of the fundamental problems in extracting the cosmic microwave background signal (CMB) from millimeter/submillimeter observations is the pollution by emission from the Milky Way: synchrotron, free-free, and thermal dust emission. To extract the fundamental cosmological parameters from CMB signal, it is mandatory to minimize this pollution since it will create systematic errors in the CMB power spectra. In previous investigations, it has been demonstrated that the neural network method provide high quality CMB maps from temperature data. Here the analysis is extended to polarization maps. As a concrete example, the WMAP 7-year polarization data, the most reliable determination of the polarization properties of the CMB, has been analysed. The analysis has adopted the frequency maps, noise models, window functions and the foreground models as provided by the WMAP Team, and no auxiliary data is included. Within this framework it is demonstrated that the network can extract the CMB polarization signal with no sign of pollution by the polarized foregrounds. The errors in the derived polarization power spectra are improved compared to the errors derived by the WMAP Team.Comment: Accepted for publication in Astrophysics & Space Scienc

DEN MUSIKALSKE PSYKOLOG? Professionslæring i musik og psykologi

Today several higher education's are organised in a theoretical part where the students first learn, after which they apply what they learned in practice. As an example, this division is recognisable in the education of psychology. Prerequisition's and problems for this sequential organisation of the education's are outlined in the article. From a research study of how piano students at the Academy of Music learn to play the piano, the strong points in a side by side model of education are emphasized, where learning the profession is mixed with participation in the profession. In that connection several co-learning elements are identified such as students being more careful in their preparations, learning from more experienced musicians and how mistakes and inspiration are important learning resources in becoming a skilled practitioner. Furthermore, it is argued that the piano students learn from being teachers themselves. These different co-learning elements from the Academy of Music are related to the education of psychologists. Finally, several reservations to these comparisons between psychology and music are made.Artiklen tager udgangspunkt i den skarpe opdeling, der kendetegner en række professionsuddannelser bl.a. psykologi, hvor de studerende først gennemgår en længerevarende teoretisk uddannelse, for så senere at anvende det lærte i praksis. Denne organisering af professionsoplæringen kaldes i denne sammenhæng for den sekventielle model. Forudsætninger og problemer med denne sekventielle model for professionsoplæring gennemgås. Med udgangspunkt i en undersøgelse fra det Jydske Musikkonservatorium af klaverstuderendes læreprocesser, argumenteres der for det hensigtsmæssige i en sideløbende organisering af professionslæringen, hvor professionsudøvelse og professionsoplæring foregår sideløbende. I den forbindelse påpeges en række medlæringsfaktorer. Eksempler fra konservatoriet viser, at når de studerende deltager i professionsudøvelsen samtidig med, at de er under uddannelse, forbereder de sig grundigere, lærer ved at betragte hvordan de erfarne griber faget an, samt at fejl og inspiration fungerer som væsentlige læringsressourcer. Endvidere påpeges det, at de studerende lærer ved selv at undervise. Forskellige muligheder for at psykologiuddannelsen kan drage nytte af indsigterne fra musikkonservatoriet fremhæves og, afslutningsvis overvejes forskellige forbehold i forbindelse med sammenligningerne mellem musik og psykologi

Deep rest-frame far-UV spectroscopy of the giant Lyman-alpha emitter 'Himiko'

We present deep 10h VLT/XSHOOTER spectroscopy for an extraordinarily luminous and extended Lya emitter at z=6.595 referred to as Himiko and first discussed by Ouchi et al. (2009), with the purpose of constraining the mechanisms powering its strong emission. Complementary to the spectrum, we discuss NIR imaging data from the CANDELS survey. We find neither for HeII nor any metal line a significant excess, with 3 sigma upper limits of 6.8, 3.1, and 5.8x10^{-18} erg/s/cm^2 for CIV $\lambda$1549, HeII $\lambda$1640, CIII] $\lambda$1909, respectively, assuming apertures with 200 km/s widths and offset by -250 km/s w.r.t to the peak Lya redshift. These limits provide strong evidence that an AGN is not a major contribution to Himiko's Lya flux. Strong conclusions about the presence of PopIII star-formation or gravitational cooling radiation are not possible based on the obtained HeII upper limit. Our Lya spectrum confirms both spatial extent and flux (8.8+/-0.5x10^{-17} erg/s/cm^2) of previous measurements. In addition, we can unambiguously exclude any remaining chance of it being a lower redshift interloper by significantly detecting a continuum redwards of Lya, while being undetected bluewards

Risk of miscarriage among users of corticosteroid hormones: A population-based nested case-control study

Background: The purpose of this nested case-control study in Denmark was to study the association between use of corticosteroids and risk of miscarriage. Methods: We identified prescriptions for corticosteroids before the miscarriage/index date. We estimated odds ratios (ORs) for miscarriage and for early (<13 weeks) and late (13-21 weeks) miscarriage adjusting for age, history of diabetes and epilepsy, and nonsteroidal anti-inflammatory drug use. Results: We identified 10,974 women with miscarriage and 109,740 controls. Prevalence of inhaled corticosteroid use within 60 days before the index date was 1.3% among the cases and 1.0% among the controls (OR = 1.20; 95% confidence interval [CI] 1.01-1.44). Prevalence of oral corticosteroid use within 60 days before the index date was 0.3% for both cases and controls (OR = 0.78; 95% CI 0.53-1.15). For inhaled and oral corticosteroids, the ORs of early miscarriage were 1.22 (95% CI 1.01-1.49) and 0.81 (95% CI 0.55-1.20), respectively. Conclusion: Use of inhaled corticosteroids was associated with a slightly increased risk of early miscarriage, but explanations alternative to causal ones were possible. © 2013 Bjørn et al, publisher and licensee Dove Medical Press Ltd