Anti-Scientific Currents in American Thought

Multifarious forces have surrounded science and continue their—sometimes separate, sometimes coordinated—attempts to supplant a scientific approach to an explanation of important questions about us and the world we inhabit. We focus here on questions pertaining to biology and medicine, but no aspect of the scientific enterprise is immune from attack; and not all of the forces aligned against it are represented. The ones considered are: religion, neoliberalism, postmodernism, the “back-to-nature” movement, bioethical obstructionism, and the current POTUS, Donald Trump. We sit in amazement that at the amount of vitriol that has been leveled at science, but try to maintain civility in response. We would be irenic, not polemic; promoting true dialogue between respected scholars holding somewhat differing views. This is not as difficult as some would have you believe

The Implications of M Dwarf Flares on the Detection and Characterization of Exoplanets at Infrared Wavelengths

We present the results of an observational campaign which obtained high time cadence, high precision, simultaneous optical and IR photometric observations of three M dwarf flare stars for 47 hours. The campaign was designed to characterize the behavior of energetic flare events, which routinely occur on M dwarfs, at IR wavelengths to milli-magnitude precision, and quantify to what extent such events might influence current and future efforts to detect and characterize extrasolar planets surrounding these stars. We detected and characterized four highly energetic optical flares having U-band total energies of ~7.8x10^30 to ~1.3x10^32 ergs, and found no corresponding response in the J, H, or Ks bandpasses at the precision of our data. For active dM3e stars, we find that a ~1.3x10^32 erg U-band flare (delta Umax ~1.5 mag) will induce <8.3 (J), <8.5 (H), and <11.7 (Ks) milli-mags of a response. A flare of this energy or greater should occur less than once per 18 hours. For active dM4.5e stars, we find that a ~5.1x10^31 erg U-band flare (delta Umax ~1.6 mag) will induce <7.8 (J), <8.8 (H), and <5.1 (Ks) milli-mags of a response. A flare of this energy or greater should occur less than once per 10 hours. No evidence of stellar variability not associated with discrete flare events was observed at the level of ~3.9 milli-mags over 1 hour time-scales and at the level of ~5.6 milli-mags over 7.5 hour time-scales. We therefore demonstrate that most M dwarf stellar activity and flares will not influence IR detection and characterization studies of M dwarf exoplanets above the level of ~5-11 milli-mags, depending on the filter and spectral type. We speculate that the most energetic megaflares on M dwarfs, which occur at rates of once per month, are likely to be easily detected in IR observations with sensitivity of tens of milli-mags.Comment: Accepted in Astronomical Journal, 17 pages, 6 figure

White Light Flare Continuum Observations with ULTRACAM

We present sub-second, continuous-coverage photometry of three flares on the dM3.5e star, EQ Peg A, using custom continuum filters with WHT/ULTRACAM. These data provide a new view of flare continuum emission, with each flare exhibiting a very distinct light curve morphology. The spectral shape of flare emission for the two large-amplitude flares is compared with synthetic ULTRACAM measurements taken from the spectra during the large 'megaflare' event on a similar type flare star. The white light shape during the impulsive phase of the EQ Peg flares is consistent with the range of colors derived from the megaflare continuum, which is known to contain a Hydrogen recombination component and compact, blackbody-like components. Tentative evidence in the ULTRACAM photometry is found for an anti-correlation between the emission of these components.Comment: 8 pages, 3 figures. Proceedings of the 16th Workshop on Cool Stars, Stellar Systems, and the Sun (PASP conference series, in press

A comparison between the FENE-P and sPTT constitutive models in Large Amplitude Oscillatory Shear (LAOS)

The FENE-P and sPTT viscoelastic models are widely used for modelling of complex fluids. Although they are derived from distinct micro-structural theories, these models can become mathematically identical in steady and homogeneous flows with a particular choice of the value of the model parameters. However, even with this choice of parameter values, the model responses are known to differ from each other in transient flows. In this work, we investigate the responses of the FENE-P and sPTT constitutive models in Large Amplitude Oscillatory Shear (LAOS). In steady-shear, the shear stress scales with the non-dimensional group $Wi/(aL) \ (Wi\sqrt{\epsilon})$ for the FENE-P (sPTT) model, where $Wi$ is the Weissenberg number, $L^2$ is the limit of extensibility in the FENE-P model ($a$ being $L^2/(L^2-3)$) and $\epsilon$ is the extensibility parameter in the sPTT model. Our numerical and analytical results show that, in LAOS, the FENE-P model only shows this universality for large values of $L^2$ whereas the sPTT model shows this universality for all values of$\epsilon$. In the strongly non-linear region, there is a drastic difference between the responses of the two models, with the FENE-P model exhibiting strong shear stress overshoots which manifest as self-intersecting secondary loops in the viscous Lissajous curves. We quantify the non-linearity exhibited by each constitutive model using the Sequence of Physical Processes framework. Despite the high degree of non-linearity exhibited by the FENE-P model, we also show using fully non-linear 1D simulations that it does not shear band in LAOS within the range of conditions studied.Comment: Submitted to Journal of Fluid Mechanic