Demonstrating Gravitational Lensing Using Solar Eclipses

As encouraged by the interesting paper “Solar eclipses as a teaching opportunity in relativity” by Overduin et al.,awe made measurements of the angular deflections of neighboring stars during the 9 March 2016 total solar eclipse as imaged by National University of Singapore (NUS) students, to verify a result of general relativity. In this project, we used these images and measured the stars’ pixel positions and transformed them to equatorial coordinates using a similar approach to Overduin et al., with a few modifications. Instead of solving to determine the pixel scale and rotation, we performed a plate solution using the software AstroImageJ which enables accounting for the image’s higher order distortion. This data is found in the image’s Flexible Image Transport System (FITS) header. Image star pair separations were then compared to their database separations after determining how the individual deflections affect angular separation. Our experimental results have large uncertainties and were deemed imprecise to confirm the effects of gravitational light deflection. We include a detailed analysis and discussion on this educational project.

On English modals, modal meaning and argument structure

In an interesting paper, Fong (2020) raises objections to my approach to English modals (and modality in general) which he views as too general and not fully compliant with the postulates of Construction Grammar. In this response paper, I intend to explain in some depth the benefits of my approach, as well as the reasons why Construction Grammar, in particular Cognitive Construction Grammar (Goldberg, 1995, 2006, 2019), needs to be interrogated and adapted as a conceptual framework to explain language learning and processing.

Discussion of ‘Detecting possibly frequent change-points: Wild Binary Segmentation 2 and steepest-drop model selection’

We congratulate the author for this interesting paper which introduces a novel method for the data segmentation problem that works well in a classical change point setting as well as in a frequent jump situation. Most notably, the paper introduces a new model selection step based on finding the ‘steepest drop to low levels’ (SDLL). Since the new model selection requires a complete (or at least relatively deep) solution path ordering the change point candidates according to some measure of importance, a new recursive variant of the Wild Binary Segmentation (Fryzlewicz in Ann Stat 42:2243–2281, 2014, WBS) named WBS2, has been proposed for candidate generation.