47,532 research outputs found
On Gradings in Khovanov homology and sutured Floer homology
We discuss generalizations of Ozsvath-Szabo's spectral sequence relating
Khovanov homology and Heegaard Floer homology, focusing attention on an
explicit relationship between natural Z (resp., 1/2 Z) gradings appearing in
the two theories. These two gradings have simple representation-theoretic
(resp., geometric) interpretations, which we also review.Comment: 17 pages, 5 figures, to be submitted to Proceedings of Jaco's 70th
Birthday Conference, 201
Phase Lags in the Optical-Infrared Light Curves of AGB Stars
To search for phase lags in the optical-infrared light curves of asymptotic
giant branch stars, we have compared infrared data from the COBE DIRBE
satellite with optical light curves from the AAVSO and other sources. We found
17 examples of phase lags in the time of maximum in the infrared vs. that in
the optical, and 4 stars with no observed lags. There is a clear difference
between the Mira variables and the semi-regulars in the sample, with the
maximum in the optical preceding that in the near-infrared in the Miras, while
in most of the semi-regulars no lags are observed. Comparison to published
theoretical models indicates that the phase lags in the Miras are due to strong
titanium oxide absorption in the visual at stellar maximum, and suggests that
Miras pulsate in the fundamental mode, while at least some semi-regulars are
first overtone pulsators. There is a clear optical-near-infrared phase lag in
the carbon-rich Mira V CrB; this is likely due to C2 and CN absorption
variations in the optical.Comment: AJ, in pres
Electric dipole moment constraints on minimal electroweak baryogenesis
We study the simplest generic extension of the Standard Model which allows
for conventional electroweak baryogenesis, through the addition of dimension
six operators in the Higgs sector. At least one such operator is required to be
CP-odd, and we study the constraints on such a minimal setup, and related
scenarios with minimal flavor violation, from the null results of searches for
electric dipole moments (EDMs), utilizing the full set of two-loop
contributions to the EDMs. The results indicate that the current bounds are
stringent, particularly that of the recently updated neutron EDM, but fall
short of ruling out these scenarios. The next generation of EDM experiments
should be sufficiently sensitive to provide a conclusive test.Comment: 20 pages, 5 figures; v2: comments added and minor corrections to the
results, published versio
County Amenities and Net Migration
U.S. county-level net migration data and a general spatial model are used to examine the effects of various amenities on migration decisions. Results suggest that higher county cancer risks and the presence of superfund sites in a county, or a higher ranking on the Environmental Protection Agency's hazard ranking system, reduce the relative attractiveness of a county to prospective migrants, while natural amenities on balance attract migrants, ceteris paribus. The results also reveal spatial dependence among contiguous counties in terms of net migration behavior.Environmental Economics and Policy,
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