8,924 research outputs found

    Evaluating Teaching Methods: Is It Worth Doing Right?

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    Reviewers of manuscripts on classroom experiments often ask the authors to provide evidence of the effectiveness of the method, presumably to justify substituting experiments for lectures. After reviewing the current state of evaluation methodology, we argue that such evidence may be neither sufficient nor even necessary for the purpose.Teaching/Communication/Extension/Profession,

    Anti-Unruh Phenomena

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    We find that a uniformly accelerated particle detector coupled to the vacuum can cool down as its acceleration increases, due to relativistic effects. We show that in (1+1)-dimensions, a detector coupled to the scalar field vacuum for finite timescales (but long enough to satisfy the KMS condition) has a KMS temperature that decreases with acceleration, in certain regimes. This contrasts with the heating that one would expect from the Unruh effect.Comment: 6 pages, 5 figures. RevTex 4.1. V2. Typos in the plots labeling corrected and plot rescaled. New discussion section added. Title change

    P-V Criticality in Quasitopological Gravity

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    We investigate the thermodynamic behaviour of AdS quasitopological black hole solutions in the context of extended thermodynamic phase space, in which the cosmological constant induces a pressure with a conjugate volume. We find that the third order exact quasitopological solution exhibits features consistent with the third order Lovelock solutions for positive quasitopological coupling, including multiple reentrant phase transitions and isolated critical points. For negative coupling we find the first instances of both reentrant phase transitions and thermodynamic singularities in five dimensions, along with other modified thermodynamic behaviour compared to Einstein-AdS-Gauss Bonnet gravity.Comment: 20 pages, 15 figures, REVTeX 4-1; updated to match published versio

    Radiation damage in selected crystals at low temperature.

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    EC02-171 Canada Thistle

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    Canada thistle [Cirsium arvense (L) Scop.] is one of the seven species defined by Nebraska law as a noxious weed. At least 35 other states also have determined by law that Canada thistle poses a threat to the economic, social, and aesthetic well-being of the residents of their state. Canada thistle is probably the most widespread of all the thistle species and many land managers consider it the most difficult thistle to control. In Nebraska, Canada thistle is estimated to infest 460,000 acres
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