57 research outputs found

    Field Measurements of Terrestrial and Martian Dust Devils

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    Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types

    Gluttony, excess, and the fall of the planter class in the British Caribbean

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    Food and rituals around eating are a fundamental part of human existence. They can also be heavily politicized and socially significant. In the British Caribbean, white slaveholders were renowned for their hospitality towards one another and towards white visitors. This was no simple quirk of local character. Hospitality and sociability played a crucial role in binding the white minority together. This solidarity helped a small number of whites to dominate and control the enslaved majority. By the end of the eighteenth century, British metropolitan observers had an entrenched opinion of Caribbean whites as gluttons. Travelers reported on the sumptuous meals and excessive drinking of the planter class. Abolitionists associated these features of local society with the corrupting influences of slavery. Excessive consumption and lack of self-control were seen as symptoms of white creole failure. This article explores how local cuisine and white creole eating rituals developed as part of slave societies and examines the ways in which ideas about hospitality and gluttony fed into the debates over slavery that led to the dismantling of slavery and the fall of the planter class

    Model comparison tests to determine data information content

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    In the context of inverse or parameter estimation problems we demonstrate the use of statistically based model comparison tests in several examples of practical interest. In these examples we are interested in questions related to information content of a particular given data set and whether the data will support a more complicated model to describe it. In the first example we compare fits for several different models to describe simple decay in a size histogram for aggregates in amyloid fibril formation. In a second example we investigate whether the information content in data sets for the pest Lygus hesperus in cotton fields as it is currently collected is sufficient to support a model in which one distinguishes between nymphs and adults. Finally in a third example with data for patients having undergone an organ transplant, we question whether the data content is sufficient to estimate more than 5 of the fundamental parameters in a particular dynamic model
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