281 research outputs found
Double-Antiprism Central Configurations of the 3n-Body Problem
Abstract In this paper we study numerically a new type of central configurations
of the 3n-body problem with equal masses which consist of three n-gons contained
in three planes z = 0 and z = ±β = 0. The n-gon on z = 0 is scaled by a factor α
and it is rotated by an angle of π/n with respect to the ones on z = ±β. In this kind
of configurations, the masses on the planes z = 0 and z = β are at the vertices of
an antiprism with bases of different size. The same occurs with the masses on z = 0
and z = −β. We call this kind of central configurations double-antiprism central
configurations. We will show the existence of central configurations of this type
Flavour singlets in gauge theory as permutations
50 pages, v2: typos corrected, v3: to appear in JHEPJHEP is an open-access journal funded by SCOAP3 and licensed under CC BY 4.
A Universal Behavior of Half BPS Probes in the Superstar Ensemble
In this paper we probe the typical states of the superstar ensemble of
(hep-th/0508023) using half-BPS states of type-IIB string theory on AdS S. We find a very simple universal result that has the structure
\log\, \lag\lag \y \; \y \rag\rag_\calo \approx \a\, h \, \log N, where
is the conformal weight of the probe \y and \a is a constant that depends
mainly of the shape of the probe \y. A complete understanding of some
properties of this leading term from the dual effective superstar geometry
point of view is still lacking.Comment: 34 pages + appendice
Lessons from giant gravitons on
We implement Mikhailov's holomorphic curve construction to explore various
properties of giant gravitons in type IIB string theory on . By coloring the D-brane worldvolume, we are able to show how, in the
string theory, the giant graviton factorizes at its maximal size into two
dibaryons - topologically stable D-branes wrapping non-contractible cycles in
the . This is related to the structure of the symmetry group of the
emergent Klebanov-Witten gauge theory being a product -
instead of the canonical . Finally, we complete this study with a
systematic and detailed construction of the spectrum of small fluctuations
about the giant graviton configuration. Curiously, we find that the fluctuation
spectrum depends on the size of the giant. The similarity of the operator
structures in the Klebanov-Witten and ABJM theories leads us to believe that
the D4-brane giant graviton in type IIA string theory on factorizes into two dibaryons in a
qualitatively similar way.Comment: 39 pages; abstract reworded slightly; additional comments included in
subsection 3.3; section 5 revised with the addition of subsection 5.3; added
reference
First report on dung beetles in intra-Amazonian savannahs in Roraima, Brazil
This is the first study to address the dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) diversity in intra-Amazonian savannahs in the state of Roraima, Brazil. Our aim was to survey the dung beetle fauna associated with these savannahs (regionally called 'lavrado'), since little is known about the dung beetles from this environment. We conducted three field samples using pitfall traps baited with human dung in savannah areas near the city of Boa Vista during the rainy seasons of 1996, 1997, and 2008. We collected 383 individuals from ten species, wherein six have no previous record in intra-Amazonian savannahs. The most abundant species were Ontherus appendiculatus (Mannerheim, 1829), Canthidium aff. humerale (Germar, 1813), Dichotomius nisus (Olivier, 1789), and Pseudocanthon aff. xanthurus (Blanchard, 1846). We believe that knowing the dung beetles diversity associated with the intra-Amazonian savannahs is ideal for understanding the occurrence and distribution of these organisms in a highly threatened environment, it thus being the first step towards conservation strategy development
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