8,947 research outputs found
On the t-Term Rank of a Matrix
For t a positive integer, the t-term rank of a (0,1)-matrix A is defined to
be the largest number of 1s in A with at most one 1 in each column and at most
t 1s in each row. Thus the 1-term rank is the ordinary term rank. We generalize
some basic results for the term rank to the t-term rank, including a formula
for the maximum term rank over a nonempty class of (0,1)-matrices with the the
same row sum and column sum vectors. We also show the surprising result that in
such a class there exists a matrix which realizes all of the maximum terms
ranks between 1 and t.Comment: 18 page
Popular Anger or Planned Pogrom? What Really Happened During Kristallnacht 78 Years Ago
Dr. Michael A. Meyer, Adolph S. Ochs Professor Emeritus, Hebrew-Union College-Jewish Institute of Religion, Cincinnati, historian, author.https://digitalcommons.fairfield.edu/bennettcenter-posters/1337/thumbnail.jp
Temperature and brain death determination: need for updated criteria
For an excellent review on the diagnosis of brain death, the interested reader is directed to the review of <a href="/journals/index.php/ni/article/view/ni.2010.e2" target="_blank">Machado</a> appearing in this journal; the author reviews all aspects of brain death and cites nine different references where the minimum temperature for brain death exams appear to have been at least 32°C. Given the new data listed above, it is clearly time for a reconsideration of the how we approach the exam for diagnosis of brain death – normal or near normal temperatures of 36°C and above are very reasonable starting points
Cyclic Matching Sequencibility of Graphs
We define the cyclic matching sequencibility of a graph to be the largest
integer such that there exists a cyclic ordering of its edges so that every
consecutive edges in the cyclic ordering form a matching. We show that the
cyclic matching sequencibility of and equal
Polarization observables in the longitudinal basis for pseudo-scalar meson photoproduction using a density matrix approach
The complete expression for the intensity in pseudo-scalar meson
photoproduction with a polarized beam, target, and recoil baryon is derived
using a density matrix approach that offers great economy of notation. A
Cartesian basis with spins for all particles quantized along a single
direction, the longitudinal beam direction, is used for consistency and clarity
in interpretation. A single spin-quantization axis for all particles enables
the amplitudes to be written in a manifestly covariant fashion with simple
relations to those of the well-known CGLN formalism. Possible sign
discrepancies between theoretical amplitude-level expressions and
experimentally measurable intensity profiles are dealt with carefully. Our
motivation is to provide a coherent framework for coupled-channel partial-wave
analysis of several meson photoproduction reactions, incorporating recently
published and forthcoming polarization data from Jefferson Lab.Comment: 11 pages, 2 figure
An Improbable Solution to the Underluminosity of 2M1207B: A Hot Protoplanet Collision Afterglow
We introduce an alternative hypothesis to explain the very low luminosity of
the cool (L-type) companion to the ~25 M_Jup ~8 Myr-old brown dwarf 2M1207A.
Recently, Mohanty et al. (2007) found that effective temperature estimates for
2M1207B (1600 +- 100 K) are grossly inconsistent with its lying on the same
isochrone as the primary, being a factor of ~10 underluminous at all bands
between I (0.8 um) and L' (3.6 um). Mohanty et al. explain this discrepency by
suggesting that 2M1207B is an 8 M_Jup object surrounded by an edge-on disk
comprised of large dust grains producing 2.5^m of achromatic extinction. We
offer an alternative explanation: the apparent flux reflects the actual source
luminosity. Given the temperature, we infer a small radius (~49,000 km), and
for a range of plausible densities, we estimate a mass < M_Jup. We suggest that
2M1207B is a hot protoplanet collision afterglow and show that the radiative
timescale for such an object is >~1% the age of the system. If our hypothesis
is correct, the surface gravity of 2M1207B should be an order of magnitude
lower than predicted by Mohanty et al. (2007).Comment: ApJ Letters, in press (11 pages
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