Effects of Digitally Enhanced Learning Tasks on Cognitive Functioning

Are brain-training applications effective? In recent years the popularity of brain training programs, such as Lumosity, Brain Age, Big Brain Academy and Elevate has increased significantly. These programs assert that the consistent use of their program can potentially result in increases in cognitive function. The current body of cognitive research shows that these programs train working memory; due to its integral part in general cognition. This research compared the effectiveness of digitally enhanced working memory tasks, versus active control groups for improvements on measures of cognitive functioning. It was hypothesized that the digitally enhanced working memory tasks would have greater improvements in cognitive functioning, to test this hypothesis this study used meta-analysis to examine and assess the current literature. Support of the hypothesis is found in specific areas of functioning such as visual-spatial working memory, fluid intelligence and processing speed. However, more research needs to be conducted with larger samples and more specific dependent measures of cognitive functioning. Practical application of these digitally enhanced working memory tasks are geared towards slowing cognitive decline in elderly populations

Artificial neural networks for selection of pulsar candidates from the radio continuum surveys

Pulsar search with time-domain observation is very computationally expensive and data volume will be enormous with the next generation telescopes such as the Square Kilometre Array. We apply artificial neural networks (ANNs), a machine learning method, for efficient selection of pulsar candidates from radio continuum surveys, which are much cheaper than time-domain observation. With observed quantities such as radio fluxes, sky position and compactness as inputs, our ANNs output the "score" that indicates the degree of likeliness of an object to be a pulsar. We demonstrate ANNs based on existing survey data by the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey (NVSS) and test their performance. Precision, which is the ratio of the number of pulsars classified correctly as pulsars to that of any objects classified as pulsars, is about 96$\%$. Finally, we apply the trained ANNs to unidentified radio sources and our fiducial ANN with five inputs (the galactic longitude and latitude, the TGSS and NVSS fluxes and compactness) generates 2,436 pulsar candidates from 456,866 unidentified radio sources. These candidates need to be confirmed if they are truly pulsars by time-domain observations. More information such as polarization will narrow the candidates down further.Comment: 11 pages, 13 figures, 3 tables, accepted for publication in MNRA

Study of systematics effects on the Cross Power Spectrum of 21 cm Line and Cosmic Microwave Background using Murchison Widefield Array Data

Observation of the 21cm line signal from neutral hydrogen during the Epoch of Reionization is challenging due to extremely bright Galactic and extragalactic foregrounds and complicated instrumental calibration. A reasonable approach for mitigating these problems is the cross correlation with other observables. In this work, we present the first results of the cross power spectrum (CPS) between radio images observed by the Murchison Widefield Array and the cosmic microwave background (CMB), measured by the Planck experiment. We study the systematics due to the ionospheric activity, the dependence of CPS on group of pointings, and frequency. The resulting CPS is consistent with zero because the error is dominated by the foregrounds in the 21cm observation. Additionally, the variance of the signal indicates the presence of unexpected systematics error at small scales. Furthermore, we reduce the error by one order of magnitude with application of a foreground removal using a polynomial fitting method. Based on the results, we find that the detection of the 21cm-CMB CPS with the MWA Phase I requires more than 99.95% of the foreground signal removed, 2000 hours of deep observation and 50% of the sky fraction coverage.Comment: 15 pages, 16 figures, accepted to MNRA