To erase or not to erase, that is not the question: Drawing from observation in an analogue or digital environment

Erasing when drawing occurs for a variety of reasons. While the most obvious may be correction of mistakes, at other times erasers are used to create such things as highlights or marks that introduce particular aesthetic elements. When a drawing is made on paper, partial erasure ‘marks’ can provide a useful record of a drawing’s evolution. For the teacher, this historical record can be a catalyst for helpful commentary and criticism. While programmed to simulate an analogue eraser, in a digital environment the erase function can eradicate a drawing’s history with a single click. We studied analogue and digital tool use behaviours (including erasing) to compare the frequency of erasure and the effect of erasing on observational accuracy in adults between the age of 17 and 64 with various levels of drawing experience from less than two years to more than ten years. The study involved participants making one drawing on paper with traditional drawing tools and one drawing on a digital drawing tablet. We then had the drawings rated for accuracy. Among other interesting results, we found that erasing occurs with greater frequency when participants work in a digital environment than in an analogue one and that, while there were significant tool use differences between the environments, those differences did not result in differences in the accuracy of final drawings indicating the adaptability of our participants using different means to achieve the same effect.

The Aarhus red giants challenge

Contact. The large quantity of high-quality asteroseismic data that have been obtained from space-based photometric missions and the accuracy of the resulting frequencies motivate a careful consideration of the accuracy of computed oscillation frequencies of stellar models, when applied as diagnostics of the model properties. Aims. Based on models of red-giant stars that have been independently calculated using different stellar evolution codes, we investigate the extent to which the differences in the model calculation affect the model oscillation frequencies and other asteroseismic diagnostics. Methods. For each of the models, which cover four different masses and different evolution stages on the red-giant branch, we computed full sets of low-degree oscillation frequencies using a single pulsation code and, from these frequencies, typical asteroseismic diagnostics. In addition, we carried out preliminary analyses to relate differences in the oscillation properties to the corresponding model differences. Results. In general, the differences in asteroseismic properties between the different models greatly exceed the observational precision of these properties. This is particularly true for the nonradial modes whose mixed acoustic and gravity-wave character makes them sensitive to the structure of the deep stellar interior and, hence, to details of their evolution. In some cases, identifying these differences led to improvements in the final models presented here and in Paper I; here we illustrate particular examples of this. Conclusions. Further improvements in stellar modelling are required in order fully to utilise the observational accuracy to probe intrinsic limitations in the modelling and improve our understanding of stellar internal physics. However, our analysis of the frequency differences and their relation to stellar internal properties provides a striking illustration of the potential, in particular, of the mixed modes of red-giant stars for the diagnostics of stellar interiors.

The accuracy of the modified Evan's blue dye test in detecting aspiration in tracheostomised patients

ObjectivesTo evaluate the sensitivity and specificity of the modified Evans blue dye test compared to the fibre-optic endoscopic evaluation of swallowing to detect aspiration in tracheostomised patients.MethodsThis observational accuracy study included 17 patients hospitalised for respiratory complications, subjected to prolonged intubation, and for this reason, tracheostomised.ResultsMean patient age was 60.2 ± 21.0 years. Aspiration was identified in 10 patients when assessed by fibre-optic endoscopic evaluation of swallowing; of these, 1 had aspiration when evaluated by modified Evans blue dye test. The dye test had a sensitivity of 10.0 per cent and specificity of 100.0 per cent for detecting aspiration. Fibre-optic endoscopic evaluation of swallowing revealed no statistically significant associations between aspiration presence and: speech and language therapy duration, intubation time, or tracheostomy plus mechanical ventilation duration.ConclusionThe modified Evans blue dye test is simple and inexpensive, and does not require prior knowledge in endoscopy; it may be used as an initial screening test in all tracheostomised patients for evaluating aspiration. However, fibre-optic endoscopic evaluation of swallowing should be used for a more comprehensive diagnosis of tracheostomy patients, especially for those at high risk for aspiration.

David Gill FRS (1843–1914): The Making of a Royal Astronomer

David Gill was an outstanding astronomer over several decades at the end of the nineteenth and into the early twentieth century. He was famous for his observational accuracy, for his painstaking attention to detail, and for his hands-on knowledge of the fine points of astronomical instrumentation. Astronomy, though, was a second professional career for David Gill. This account maps out the surprising and unusual path of David Gill’s life before he became Her Majesty’s Astronomer at the Cape of Good Hope. It covers aspects of his education, his horological career, his employment by Lord Lindsay to oversee the Dunecht observatory, his personal expedition to Ascension Island and his appointment as Her Majesty’s Astronomer at the age of 34. The account includes local detail and images not found in the main biography of David Gill. It ends with some detail of Gill’s continuing interest in clocks after his appointment.

Restrictions on Extended Gravity at Galaxy Clusters Scales

Following [1] we discuss the predictions of Starobinsky model of f(R)-gravity with vanishing cosmological constant at galaxy and galaxy clusters scales. As a result we demonstrate that at the current observational accuracy level there is no significant difference in cut-off radius values for Starobinsky model and general relativity (GR) in the mass range from 109MS un till galaxy clusters ones (1018MS un) that shows the good applicability of GR at these ranges.

Using spatial technology to locate the view illustrated in Eugene von Guérard’s painting of the Kosciuszko massif

The colonial artist Eugene von Guérard travelled extensively throughout south-eastern Australia sketching thousands of views during his three-decade-long sojourn in Australia. His field drawings are renowned for their fidelity to nature and observational accuracy, but the validity of the latter claim depends on comparing drawings with the view at the sites where he sketched. The location of the view in some artworks, such as Mount Kosciusko, seen from the Victorian Border, has eluded art historians and aficionados who have ventured into the field. This article discusses the collation of clues from historical narratives, maps and surveying techniques to limit the search area for the vantage point where he sketched the view on which he based his painting of the Kosciuszko massif. Novel use of spatial technology utilising satellite imagery, Global Positioning System (GPS) and Shuttle Radar Topography Mission (SRTM) data, particularly digital elevation models, to locate the actual site is explored, and the topographical accuracy of his sketches evaluated when compared with photographs taken from close to the site. Finally, the potential value of using spatial technology in art history field work is discussed.

Signal Processing on Precursory “Fingerprint” Image Pattern Feature of Yushu Earthquake

Precursory earthquake data are linked closely to the earthquake processes. Taking the Tibetan Autonomous Region’s Yushu County earthquake as an example, we analyzed three types of earthquake signals and studied a modeling method for self-adaptative matching warning data on precursory data’s fingerprint features. We calculated different timescale features of precursory fingerprint pattern images based on statistical physics and image matching. We also developed corresponding fuzzy discriminant rules and established a database of warning-image fingerprint pattern features for the Yushu County region and studied evolutionary laws for the data feature patterns under different time scales during abnormal development in front of and behind of abnormal development. Result were similar to the general “fingerprint” pattern feature among precursory earthquake data for different signal channels, but the details of these characteristics are completely different. This special “fingerprint” image pattern feature is useful as on early warning of possible geological follow-up activity. Our method could improve the limitations on and low efficiency of manual handling and could also heighten observational accuracy and work efficiency.

The observational analysis of elite coaches within youth soccer: The importance of performance analysis

The study investigated the observational capabilities of experienced elite coaches whilst focusing upon soccer specific actions and playing positions within elite youth soccer. Six soccer coaches assessed the performances of 10 youth soccer players (across 8 matches) on their short/long passing, tackling, shooting, heading and dribbling. Analysis was undertaken on an overall, quality and positional grouping basis. Mean observational accuracy was 38.8%, with successful shooting (78.6%) and passing (29.9%) illustrating the range. The limited effective observation of dribbling (37.2%), often considered a separating factor within talent identification, highlights the need for objective measures to aid such processes. Positional grouping analysis elicited ∼20% more effective observation for unsuccessful compared with successful actions. The poor level of observational accuracy identified herein has significant implications on talent identification assessments devoid of post-performance analyses. The findings reinforce the importance of performance analysis in the provision of highly accurate and comprehensive augmented feedback within the coaching process.