17,349 research outputs found
Set Systems Containing Many Maximal Chains
The purpose of this short problem paper is to raise an extremal question on
set systems which seems to be natural and appealing. Our question is: which set
systems of a given size maximise the number of -element chains in the
power set ? We will show that for each fixed
there is a family of sets containing
such chains, and that this is asymptotically best possible. For smaller set
systems we are unable to answer the question. We conjecture that a `tower of
cubes' construction is extremal. We finish by mentioning briefly a connection
to an extremal problem on posets and a variant of our question for the grid
graph.Comment: 5 page
Higgs Assisted Q-balls from Pseudo-Nambu-Goldstone Bosons
Motivated by recent constructions of TeV-scale strongly-coupled dynamics,
either associated with the Higgs sector itself as in pseudo-Nambu-Goldstone
boson (pNGB) Higgs models or in theories of asymmetric dark matter, we show
that stable solitonic Q- balls can be formed from light pion-like pNGB fields
carrying a conserved global quantum number in the presence of the Higgs field.
We focus on the case of thick-wall Q-balls, where solutions satisfying all
constraints are shown to exist over a range of parameter values. In the limit
that our approximations hold, the Q-balls are weakly bound and parametrically
large, and the form of the interactions of the light physical Higgs with the
Q-ball is determined by the breaking of scale symmetry.Comment: 24 pages, 6 figures, 1 tabl
We Need Men: the Union Draft in the Civil War
Review of: We Need Men: The Union Draft in the Civil War. Geary, James W
Collection and Preservation of Food Crop Germplasm with Wide Genetic Diversity
Discussion by Russell T. Johnson of a project envisaging a number of committees devoted to the genetic diversity of particular crops, and to assessing the adequacy and requirements of existing germplasm collections, documenting the collections in a way accessible throughout the world to scientists working on those crops, and planning for the long term preservation of germplasm. Four such committees were already extant for Wheat, Barley and Rye, Maize, Sorghum and Millet, and Rice. Agenda item presented at TAC Second Meeting, October 1971
Montclair High School: A Multi-dimensional GIS Approach to Tactical Emergency Response
“This marks the fourth shooting incident at a U.S. school within a week -- the second at a college or university -- and serves as a stunning reminder that it is impossible to know when and where violence will occur.” (Knapp, 02/15/2008)
This quote, referencing the 2008 shooting at Northern Illinois University, is a stark reminder that the school systems in the United States are soft targets for acts of violence. Although it is almost impossible to predict such tragic events, it is possible to prepare, react, and respond to these actions in a timely manner to reduce loss of life and property. Advances in technology, particularly in geographic information systems (GIS), have given first responders the ability to respond to these occurrences more rapidly and efficiently. The GIS application created in this project supports the needs of first responders to enhance preparation and response to emergencies, in this case at Montclair High School, Montclair, California. Utilizing a variety of geospatial tools and software applications, the system will provide emergency personnel with a unique application or system designed to support a more effective and efficient response
Earhart County: The Making Of A World War Two Wondertale
Full version unavailable due to 3rd party copyright restrictions.The aim of Earhart County was to create a book which would bring the world of World War Two aviation to a mainstream audience, utilising the magic and durability of folklore to mythologize the incredible feats of Churchill’s finest generation. Whilst entertaining its audience, it aims at giving them a glimpse at the many lives and aircraft that flew during the war.
Research was conducted mainly through the study of autobiographical and biographical accounts of both famous and unknown aircrew, as well as post-war and contemporary fiction, aircraft manuals and books detailing the various aeroplanes flown throughout the war. Research was also made into the Russian wondertale and Vladimir Propp’s morphology.
The result was the novel Earhart County, a novel which was planned using the structures and devices of the wondertale whilst constantly referencing the world of aviation.
- …