4,568 research outputs found
Mutants and SU(3)_q invariants
Details of quantum knot invariant calculations using a specific
SU(3)_q-module are given which distinguish the Conway and Kinoshita-Teresaka
pair of mutant knots. Features of Kuperberg's skein-theoretic techniques for
SU(3)_q invariants in the context of mutant knots are also discussed.Comment: 17 pages. Published copy, also available at
http://www.maths.warwick.ac.uk/gt/GTMon1/paper18.abs.htm
High-resolution UKIRT observations of circumnuclear star formation in M100
We present high-resolution, near-infrared imaging of the circumnuclear region
of the barred spiral galaxy M100 (=NGC 4321), accompanied by near-infrared
spectroscopy. We identify a total of 43 distinct regions in the K-band image,
and determine magnitudes and colours for 41 of them. By comparison with other
near-infrared maps we also derive colour excesses and K-band extinctions for
the knots. Combining the imaging and spectroscopic results, we conclude that
the knots are the result of bursts of star formation within the last 15-25 Myr.
We discuss the implications of these new results for our dynamical and
evolutionary understanding of this galaxy.Comment: 10 pages, 4 figures, uses mn-1.4.sty. Accepted for publication in
Monthly Notices of the Royal Astronomical Societ
Dirac equation in spacetimes with torsion and non-metricity
Dirac equation is written in a non-Riemannian spacetime with torsion and
non-metricity by lifting the connection from the tangent bundle to the spinor
bundle over spacetime. Foldy-Wouthuysen transformation of the Dirac equation in
a Schwarzschild background spacetime is considered and it is shown that both
the torsion and non-metricity couples to the momentum and spin of a massive,
spinning particle. However, the effects are small to be observationally
significant.Comment: 12 pages LATEX file, no figures, to appear in Int. J. Mod. Phys.
Workshop on Geology of the Apollo 17 Landing Site
The topics covered include the following: petrology, lithology, lunar rocks, lunar soil, geochemistry, lunar geology, lunar resources, oxygen production, ilmenite, volcanism, highlands, lunar maria, massifs, impact melts, breccias, lunar crust, Taurus-Littrow, minerals, site selection, regolith, glasses, geomorphology, basalts, tectonics, planetary evolution, anorthosite, titanium oxides, chemical composition, and the Sudbury-Serenitatis analogy
Proca equations derived from first principles
Gersten has shown how Maxwell equations can be derived from first principles,
similar to those which have been used to obtain the Dirac relativistic electron
equation. We show how Proca equations can be also deduced from first
principles, similar to those which have been used to find Dirac and Maxwell
equations. Contrary to Maxwell equations, it is necessary to introduce a
potential in order to transform a second order differential equation, as the
Klein-Gordon equation, into a first order differential equation, like Proca
equations.Comment: 6 page
Invariants of genus 2 mutants
Pairs of genus 2 mutant knots can have different Homfly polynomials, for
example some 3-string satellites of Conway mutant pairs. We give examples which
have different Kauffman 3-variable polynomials, answering a question raised by
Dunfield et al in their study of genus 2 mutants. While pairs of genus 2 mutant
knots have the same Jones polynomial, given from the Homfly polynomial by
setting v=s^2, we give examples whose Homfly polynomials differ when v=s^3. We
also give examples which differ in a Vassiliev invariant of degree 7, in
contrast to satellites of Conway mutant knots.Comment: 16 pages, 20 figure
Prediction of unstable crack length in aluminium alloys
A method was set down for predicting the unstable length of a
crack in a flat sheet of aluminium alloy subjected to a steady tensile
stress.
The basis of the method was to take the work done to failure in
the 'neck' region of a tensile test specimen and apply it, with a
suitable constraint factor, to the flat sheet to give the work rate
required to propagate the crack.
Experimental evidence is produced in support of the method
Prediction of unstable crack length in aluminium alloys
A method was set down for predicting the unstable length of a
crack in a flat sheet of aluminium alloy subjected to a steady tensile
stress.
The basis of the method was to take the work done to failure in
the 'neck' region of a tensile test specimen and apply it, with a
suitable constraint factor, to the flat sheet to give the work rate
required to propagate the crack.
Experimental evidence is produced in support of the method
Without the White Coat: An Analysis of Pathographies by Physicians with Cancer
https://digitalcommons.unmc.edu/emet_posters/1000/thumbnail.jp
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