27 research outputs found
Macdonald Polynomials from Sklyanin Algebras: A Conceptual Basis for the -Adics-Quantum Group Connection
We establish a previously conjectured connection between -adics and
quantum groups. We find in Sklyanin's two parameter elliptic quantum algebra
and its generalizations, the conceptual basis for the Macdonald polynomials,
which ``interpolate'' between the zonal spherical functions of related real and
\--adic symmetric spaces. The elliptic quantum algebras underlie the
\--Baxter models. We show that in the n \air \infty limit, the Jost
function for the scattering of {\em first} level excitations in the
\--Baxter model coincides with the Harish\--Chandra\--like \--function
constructed from the Macdonald polynomials associated to the root system .
The partition function of the \--Baxter model itself is also expressed in
terms of this Macdonald\--Harish\--Chandra\ \--function, albeit in a less
simple way. We relate the two parameters and of the Macdonald
polynomials to the anisotropy and modular parameters of the Baxter model. In
particular the \--adic ``regimes'' in the Macdonald polynomials correspond
to a discrete sequence of XXZ models. We also discuss the possibility of
``\--deforming'' Euler products.Comment: 25 page
Simple does not mean poor: grasslands and forests harbor similar ant species richness and distinct composition in highlands of southern Brazil
Several studies addressed ant communities in the dense Atlantic Forest that runs along the Brazilian coast.
However, comparatively little is known about the mixed forests and grasslands that occur in the southern range
of the Atlantic Forest domain. In this study we performed the first standardized assessment of ants in the forest-
grassland mosaic found in the highlands of the state of Santa Catarina. We aimed to investigate and compare ant
richness and composition between mixed forests and grasslands in the main mountain range of south Brazil. Ants
were collected in two years with ground pitfalls, tree pitfalls and litter samples. Sixty ant species were recorded,
resulting in 22 new records for âPlanalto Serranoâ region and three for the state of Santa Catarina:
Eurhopalothrix
depressa
,
Pheidole radoszkowskii
and
Wasmannia williamsoni
. There was significant dissimilarity in ant species
composition between grasslands and forests, but no difference in ant species richness, even considering the
higher number of strata in mixed forests. Similar richness and low number of arboreal species suggest that this
ant community is structured similarly to temperate ones. Both habitats presented a large proportion of exclusive
species. The fact that species composition between grassland and forest areas differed, coupled with the similarity
in species richness between habitats and the record of new ant species for the region, calls for strong conservation
efforts in grasslands of southern Brazil, which still are little protected by conservation areas