Near IR and visual polarimetry of the Planetary Nebula M2-9

Bipolar and more complex morphologies observed in planetary nebulae have been explained by two principal hypotheses: by the existence of a companion producing a circumstellar disk, by the effects of a magnetic field, or by a combination of both. The polarimetric analysis of these objects could give information about the presence of dust grains aligned with any preferential direction, due to a magnetic field or to the action of radiative torques (RAT). We performed polarimetric observations of some planetary nebulae in order to detect linear polarization and (in the best scenario) to detect the signature of an accretion disk in these objects. We observed in the visual region with POLIMA at the San Pedro Mártir observatory, and with POLICAN the NIR polarimeter in the Guillermo Haro observatory. We present the result of these observations in one of these objects: the PN M2-9.

Modality switch effects emerge early and increase throughout conceptual processing: Evidence from ERPs

This repository contains all of the data from our study, including: conference paper and poster, stimuli norming, experiment set-up, behavioural pretest, main behavioural and electrophysiological data, and extensive R code for descriptives, plots, and statistical analysis.AbstractWe tested whether conceptual processing is modality-specific by tracking the time course of the Conceptual Modality Switch effect. Forty-six participants verified the relation between property words and concept words. The conceptual modality of consecutive trials was manipulated in order to produce an Auditory-to-visual switch condition, a Haptic-to-visual switch condition, and a Visual-to-visual, no-switch condition. Event-Related Potentials (ERPs) were time-locked to the onset of the first word (property) in the target trials so as to measure the effect online and to avoid a within-trial confound. A switch effect was found, characterized by more negative ERP amplitudes for modality switches than no-switches. It proved significant in four typical time windows from 160 to 750 milliseconds post word onset, with greater strength in the Slow group, in posterior brain regions, and in the N400 window. The earliest switch effect was located in the language brain region, whereas later it was more prominent in the visual region. In the N400 and Late Positive windows, the Quick group presented the effect especially in the language region, whereas the Slow had it rather in the visual region. These results suggest that contextual factors such as time resources modulate the engagement of linguistic and embodied systems in conceptual processing.Bernabeu, P., Willems, R. M., & Louwerse, M. M. (2017). Modality switch effects emerge early and increase throughout conceptual processing: Evidence from ERPs. In G. Gunzelmann, A. Howes, T. Tenbrink, & E. J. Davelaar (Eds.), Proceedings of the 39th Annual Conference of the Cognitive Science Society (pp. 1629-1634). Austin, TX: Cognitive Science Society. https://mindmodeling.org/cogsci2017/papers/0318/See also later analyses available here. These will be included in a forthcoming journal article.ReferencesCollins, J., Pecher, D., Zeelenberg, R., & Coulson, S. (2011). Modality switching in a property verification task: an ERP study of what happens when candles flicker after high heels click. Frontiers in Psychology, 2.Hald, L. A., Marshall, J.-A., Janssen, D. P., & Garnham, A. (2011). Switching modalities in a sentence verification task: ERP evidence for embodied language processing. Frontiers in Psychology, 2.Hauk, O. (2016). Only time will tell—Why temporal information is essential for our neuroscientific understanding of semantics. Psychonomic Bulletin & Review, 23.Louwerse, M., & Connell, L. (2011). A taste of words: linguistic context and perceptual simulation predict the modality of words. Cognitive Science, 35, 2, 381-98.Mahon, B.Z., & Hickok, G. (2016). Arguments about the nature of concepts: Symbols, embodiment, and beyond. Psychonomic Bulletin & Review, 23, 941-958.The modality exclusivity norms used for the stimuli are attached to this project as a linked component.Plot waveforms within any sections of the data (https://pablobernabeu.shinyapps.io/ERP-waveform-visualization_CMS-experiment/), and see the more general visualizations (https://figshare.com/articles/EEG_study_on_conceptual_modality-switching_Bernabeu_et_al_in_prep_/4210863).

SKYMONITOR: A Global Network for Night Sky Brightness Measurements

We have deployed a network of autonomous photometers that continuously measures the night sky brightness in the visual region at two sky positions simultaneously, typically near the zenith and the second at an elevation angle of 20 degrees. The Photometers are calibrated as a network to better than 5.

A Spectroscopic Abundance Study of Dwarf Cepheid V1719 Cygni

Spectroscopic CCD observations were carried out for V1719 Cygni and the spectrum in the visual region is analysed relative to the Sun with a line-blanketed convective model atmosphere. Adopted atmospheric parameters are : an effective temperature < Teff > = 7000 K, a surface gravity logg = 3.4. Although our result is dependent on microturbulent velocity and damping constant, it was found that Mg in V1719 Cygni is nearly solar, or underabundent by 0.2 to 0.3 dex according to the analysis of 5172.684 Å MgI line which is relatively free from blending. This is inconsistent with the previous photometric result where VI719 Cygni was known as an abnormally metal rich variable. Because the analysis was given to the single magnesium line which is not a good metallicity indicator and S/N ratio was low due to poor seeing condition, the investigation for iron lines in blue region is undertaken.