6,413 research outputs found
A Computer Algorithm For Engineering Off-Shell Multiplets With Four Supercharges On The World Sheet
We present an adinkra-based computer algorithm implemented in a Mathematica
code and use it in a limited demonstration of how to engineer off-shell,
arbitrary N-extended world-sheet supermultiplets. Using one of the outputs from
this algorithm, we present evidence for the unexpected discovery of a
previously unknown 8 - 8 representation of N = 2 world sheet supersymmetry. As
well, we uncover a menagerie of (p, q) = (3, 1) world sheet supermultiplets.Comment: 52 pages, 64 figures, LaTeX twice, added note in proof, addition of
comments about gauge invariance for 4D vector & tensor supermultiplet
The Technology of Terror: Accounting for the Strategic Use of Terrorism
To comprehend why a group would intentionally target civilians, we need to understand why other groups do not. In this chapter, we argue that disgruntled groups face three main choices when addressing their dissatisfaction: suffering a disadvantageous peace, engaging in unconventional warfare, or engaging in conventional warfare. We further disaggregate the choice of unconventional warfare into terrorism and guerrilla warfare. By focusing on asymmetrical aspects of the problem and the strategic interactions between the insurgent group, its complicit public, and the superior force of the state, we disentangle the technology of terror.
The early expansion and evolutionary dynamics of POU class genes.
The POU genes represent a diverse class of animal-specific transcription factors that play important roles in neurogenesis, pluripotency, and cell-type specification. Although previous attempts have been made to reconstruct the evolution of the POU class, these studies have been limited by a small number of representative taxa, and a lack of sequences from basally branching organisms. In this study, we performed comparative analyses on available genomes and sequences recovered through "gene fishing" to better resolve the topology of the POU gene tree. We then used ancestral state reconstruction to map the most likely changes in amino acid evolution for the conserved domains. Our work suggests that four of the six POU families evolved before the last common ancestor of living animals-doubling previous estimates-and were followed by extensive clade-specific gene loss. Amino acid changes are distributed unequally across the gene tree, consistent with a neofunctionalization model of protein evolution. We consider our results in the context of early animal evolution, and the role of POU5 genes in maintaining stem cell pluripotency
A Note on Embedding of M-Theory Corrections into Eleven-Dimensional Superspace
By analyzing eleven-dimensional superspace fourth-rank superfield strength
F-Bianchi identities, we show that M-theory corrections to eleven-dimensional
supergravity can not be embedded into the mass dimension zero constraints, such
as the (\g^{a b})_{\a\b} X_{a b}{}^c or i (\g^{a_1... a_5})_{\a\b} X_{a_1...
a_5}{}^c -terms in the supertorsion constraint T_{\a\b}{}^c. The only possible
modification of superspace constraint at dimension zero is found to be the
scaling of F_{\a\b c d} like F_{\a\b c d} = (1/2) \big(\g_{c d}\big)_{\a\b}
e^\Phi for some real scalar superfield \Phi, which alone is further shown not
enough to embed general M-theory corrections. This conclusion is based on the
dimension zero F-Bianchi identity under the two assumptions: (i) There are no
negative dimensional constraints on the F-superfield strength: F_{\a\b\g\d} =
F_{\a\b\g d} =0; (ii) The supertorsion T-Bianchi identities and F-Bianchi
identities are not modified by Chern-Simons terms. Our result can serve as a
powerful tool for future exploration of M-theory corrections embedded into
eleven-dimensional superspace supergravity.Comment: 14 pages, latex, some minor typos corrected, as well as old section 5
deleted, due to the subtlety about Chern-Simons term in F-Bianchi identitie
On Graph-Theoretic Identifications of Adinkras, Supersymmetry Representations and Superfields
In this paper we discuss off-shell representations of N-extended
supersymmetry in one dimension, ie, N-extended supersymmetric quantum
mechanics, and following earlier work on the subject codify them in terms of
certain graphs, called Adinkras. This framework provides a method of generating
all Adinkras with the same topology, and so also all the corresponding
irreducible supersymmetric multiplets. We develop some graph theoretic
techniques to understand these diagrams in terms of a relatively small amount
of information, namely, at what heights various vertices of the graph should be
"hung".
We then show how Adinkras that are the graphs of N-dimensional cubes can be
obtained as the Adinkra for superfields satisfying constraints that involve
superderivatives. This dramatically widens the range of supermultiplets that
can be described using the superspace formalism and organizes them. Other
topologies for Adinkras are possible, and we show that it is reasonable that
these are also the result of constraining superfields using superderivatives.
The family of Adinkras with an N-cubical topology, and so also the sequence
of corresponding irreducible supersymmetric multiplets, are arranged in a
cyclical sequence called the main sequence. We produce the N=1 and N=2 main
sequences in detail, and indicate some aspects of the situation for higher N.Comment: LaTeX, 58 pages, 52 illustrations in color; minor typos correcte
A Superfield for Every Dash-Chromotopology
The recent classification scheme of so-called adinkraic off-shell
supermultiplets of N-extended worldline supersymmetry without central charges
finds a combinatorial explosion. Completing our earlier efforts, we now
complete the constructive proof that all of these trillions or more of
supermultiplets have a superfield representation. While different as
superfields and supermultiplets, these are still super-differentially related
to a much more modest number of minimal supermultiplets, which we construct
herein.Comment: 13 pages, integrated illustration
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Census Snapshot: United States
Using data from the U.S. Census Bureau, this report provides demographic and economic information about same-sex couples and same-sex couples raising children in the U.S. We compare same-sex "unmarried partners," which the Census Bureau defines as an unmarried couple who "shares living quarters and has a close personal relationship," to different-sex married couples in the U.S
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