2,155 research outputs found
Periodic Planar Disk Packings
Several conditions are given when a packing of equal disks in a torus is
locally maximally dense, where the torus is defined as the quotient of the
plane by a two-dimensional lattice. Conjectures are presented that claim that
the density of any strictly jammed packings, whose graph does not consist of
all triangles and the torus lattice is the standard triangular lattice, is at
most , where is the number of packing
disks. Several classes of collectively jammed packings are presented where the
conjecture holds.Comment: 26 pages, 13 figure
The comparative biology of ethanol consumption: An introduction to the symposium
In classical Greek, the word “symposium” signifies a drinking party held for the purposes of intellectual discussion. This symposium introduces a new evolutionary perspective on an ancient question: why are many animals, including humans, attracted to ethanol? Recent research has shown that behavioral responses to ethanol and molecular pathways of inebriation are shared among many taxa (Wolf and Heberlein, 2003), and that the preferences of modern humans for alcohol consumption may derive from the diets of our fruit-eating ancestors (i.e., alcoholism as evolutionary hangover; Dudley, 2000, 2002). Placement of ethanol consumption within historical and comparative contexts may thus yield insight into contemporary patterns of human consumption and excessive use
Negative-frequency modes in quantum field theory
We consider a departure from standard quantum field theory, constructed so as
to permit momentum eigenstates of both positive and negative energy. The
resulting theory is intriguing because it brings about the cancellation of
leading ultra-violet divergences and the absence of a zero-point energy. The
theory gives rise to tree-level source-to-source transition amplitudes that are
manifestly causal and consistent with standard S-matrix elements. It also leads
to the usual result for the oblique corrections to the standard electroweak
theory. Remarkably, the latter agreement relies on the breakdown of naive
perturbation theory due to resonance effects. It remains to be shown that there
are no problems with perturbative unitarity.Comment: 15 pages. Prepared for the proceedings of DISCRETE2014: the Fourth
Symposium on Prospects in the Physics of Discrete Symmetries, King's College
London, to appear in the Journal of Physics: Conference Series (JPCS).
Presented by P. Millingto
The Raman Spectrum of Gypsum
In an investigation of the Raman spectra of some ionized substances in aqueous solution, it was found [1] that the frequency shift given by a solution of potassium carbonate was in fairly close agreement with the strongest shift given by calcite. Data for such a comparison in other cases do not appear to exist, for change of frequency on scattering has been measured for only a few crystalline substances. In addition to calcite [2,3,5], these are quartz [2,3,4,5], ice [5], and topaz [6]. No modified frequencies were found in the light scattered by halite [2], NaCl, fluorite [5], CaF2, or by the salts [7] LiF and NaF. In the present paper are described the results of measurements on gypsum, CaSO4•2H20, and a comparison of these with data on ammonium sulfate solution
Cognitive Dissonance, Pessimism, and Behavioral Spillover Effects
This paper reports results from a unique two-stage experiment designed to examine the spillover effects of optimism and pessimism. In stage 1, we induce optimism or pessimism onto subjects by randomly assigning a high or low piece rate for performing a cognitive task. We find that participants receiving the low piece rate are significantly more pessimistic with respect to performance on this task. In stage 2 individuals participate in an ultimatum game. We find that minimum acceptable offers are significantly lower for pessimistic subjects, though this pessimism was generated in a completely unrelated environment. These results highlight the existence of important spillover effects that can be behaviorally and economically important - for example, pessimism regarding one’s initial conditions (e.g., living in poverty) may have spillover effects on one’s future labor market outcomes.
Welcome to Carbon Balance and Management
We are pleased to announce the launch of Carbon Balance and Management, a new online open access journal published by BioMed Central
Fun Ship Marketing Philosophy
The President of Carnival Cruise Lines discusses his company\u27s philosophy and operations as they relate to the Fun Ship cruise experience. Carnival, the world\u27s largest cruise line, is positioned as a model in the business
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