21,738 research outputs found
Red-blue clique partitions and (1-1)-transversals
Motivated by the problem of Gallai on -transversals of -intervals,
it was proved by the authors in 1969 that if the edges of a complete graph
are colored with red and blue (both colors can appear on an edge) so that there
is no monochromatic induced and then the vertices of can be
partitioned into a red and a blue clique. Aharoni, Berger, Chudnovsky and Ziani
recently strengthened this by showing that it is enough to assume that there is
no induced monochromatic and there is no induced in {\em one of the
colors}. Here this is strengthened further, it is enough to assume that there
is no monochromatic induced and there is no on which both color
classes induce a .
We also answer a question of Kaiser and Rabinovich, giving an example of six
-convex sets in the plane such that any three intersect but there is no
-transversal for them
Calculations of nuclear quasi-bound states based on chiral meson-baryon amplitudes
In-medium scattering amplitudes developed within a new chirally
motivated coupled-channel model due to Cieply and Smejkal that fits the recent
SIDDHARTA kaonic hydrogen 1s level shift and width are used to construct
nuclear potentials for calculations of nuclear quasi-bound states. The
strong energy and density dependence of scattering amplitudes at and near
threshold leads to potential depths MeV.
Self-consistent calculations of all nuclear quasi-bound states, including
excited states, are reported. Model dependence, polarization effects, the role
of p-wave interactions, and two-nucleon absorption modes
are discussed. The absorption widths are comparable or even
larger than the corresponding binding energies for all nuclear
quasi-bound states, exceeding considerably the level spacing. This discourages
search for nuclear quasi-bound states in any but lightest nuclear
systems.Comment: 12 pages, 11 figure
The Last Fire-Eater: Roger A. Pryor and the Search for Southern Identity
Reviewer Howell K. Kaiser writes that William A. Link\u27s The Last Fire-Eater: Roger A. Pryor and the Search for Southern Identity shows that R.A. Pryor\u27s remarkable—and at times contradictory—transformations mirrored the puzzling journey of the South before, during, and after the Civil War
Investigation looking at the repeatability of 20 Society of Master Saddlers (SMS) qualified saddle fitters’ observations during static saddle fit
Saddle fit is widely considered to be a crucial factor for the health and performance of riding horses; however, there have been no studies looking at the agreement between professionals who fit and assess saddles. The aim of the study was to determine the agreement between Society of Master Saddlers (SMSs) qualified saddle fitters when statically fitting a saddle following the SMS guidelines. Twenty SMS qualified saddle fitter volunteers were recruited via social media and asked to statically assess the fit of the saddle following the “7 points of saddle fit” guidelines of the SMS in 10 horses. Descriptive statistics and Fleiss Kappa (as a measure of agreement beyond chance) were used to determine agreement between fitters. Agreement varied from slight to substantial between the different saddle assessment criteria with the assessment of overall saddle fit resulting in a fair agreement of k = 0.32. Substantial agreement was found for saddle clearance front (k = 0.66), top (k = 0.78), and rear (k = 0.81). Fair agreement was found for clearance of the saddle—side (k = 0.28) and how the girth straps line up with girth groove (k = 0.31) and panel contact (k = 0.38). Slight agreement was found for tree width and length (k = 0.12) and tree length (k = 0.12). Horse height in some criteria affected agreement. Agreement varied between the standard criteria. In cases where it was difficult to visually evaluate saddle fit, agreement was lower. Further work should aim to standardize the criteria which had suboptimal agreement
Getting in Sync: Revamping Licensure and Preparation for Teachers in Pre-K, Kindergarten and the Early Grades
Outlines the challenges in teacher preparation and licensure, with a focus on pre-K through third grade; promising practices such as increased classroom experience and selectivity; and suggestions for improving teacher preparation programs and policies
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