284 research outputs found
Infinite-dimensional -adic groups, semigroups of double cosets, and inner functions on Bruhat--Tits builldings
We construct -adic analogs of operator colligations and their
characteristic functions. Consider a -adic group , its subgroup , and the subgroup
embedded to diagonally. We show that double cosets
admit a structure of a semigroup, acts naturally in -fixed vectors
of unitary representations of . For each double coset we assign a
'characteristic function', which sends a certain Bruhat--Tits building to
another building (buildings are finite-dimensional); image of the distinguished
boundary is contained in the distinguished boundary. The latter building admits
a structure of (Nazarov) semigroup, the product in corresponds to a
point-wise product of characteristic functions.Comment: new version of the paper, 47pp, 3 figure
Challenges of beta-deformation
A brief review of problems, arising in the study of the beta-deformation,
also known as "refinement", which appears as a central difficult element in a
number of related modern subjects: beta \neq 1 is responsible for deviation
from free fermions in 2d conformal theories, from symmetric omega-backgrounds
with epsilon_2 = - epsilon_1 in instanton sums in 4d SYM theories, from
eigenvalue matrix models to beta-ensembles, from HOMFLY to super-polynomials in
Chern-Simons theory, from quantum groups to elliptic and hyperbolic algebras
etc. The main attention is paid to the context of AGT relation and its possible
generalizations.Comment: 20 page
Exclusive photoproduction of pi degrees up to large values of Mandelstam variables s, t, and u with CLAS
Exclusive photoproduction cross sections have been measured for the process
with the Dalitz decay final state
using tagged photon energies in the range of GeV.
The complete angular distribution of the final state , for the entire
photon energy range up to large values of and , has been measured for
the first time. The data obtained show that the cross section , at
mid to large angles, decreases with energy as . This is in
agreement with the perturbative QCD quark counting rule prediction of . Paradoxically, the size of angular distribution of measured cross sections
is greatly underestimated by the QCD based Generalized Parton Distribution
mechanism at highest available invariant energy GeV. At the same
time, the Regge exchange based models for photoproduction are more
consistent with experimental data.Comment: 7 pages, 6 figure
Underperformance of African protected area networks and the case for new conservation models : insights from Zambia
Many African protected areas (PAs) are not functioning effectively. We reviewed the performance of Zambia’s PA network
and provide insights into how their effectiveness might be improved. Zambia’s PAs are under-performing in ecological,
economic and social terms. Reasons include: a) rapidly expanding human populations, poverty and open-access systems in
Game Management Areas (GMAs) resulting in widespread bushmeat poaching and habitat encroachment; b) underfunding
of the Zambia Wildlife Authority (ZAWA) resulting in inadequate law enforcement; c) reliance of ZAWA on extracting
revenues from GMAs to cover operational costs which has prevented proper devolution of user-rights over wildlife to
communities; d) on-going marginalization of communities from legal benefits from wildlife; e) under-development of the
photo-tourism industry with the effect that earnings are limited to a fraction of the PA network; f) unfavourable terms and
corruption which discourage good practice and adequate investment by hunting operators in GMAs; g) blurred
responsibilities regarding anti-poaching in GMAs resulting in under-investment by all stakeholders. The combined effect of
these challenges has been a major reduction in wildlife densities in most PAs and the loss of habitat in GMAs. Wildlife fares
better in areas with investment from the private and/or NGO sector and where human settlement is absent. There is a need
for: elevated government funding for ZAWA; greater international donor investment in protected area management; a shift
in the role of ZAWA such that they focus primarily on national parks while facilitating the development of wildlife-based
land uses by other stakeholders elsewhere; and new models for the functioning of GMAs based on joint-ventures between
communities and the private and/or NGO sector. Such joint-ventures should provide defined communities with ownership
of land, user-rights over wildlife and aim to attract long-term private/donor investment. These recommendations are
relevant for many of the under-funded PAs occurring in other African countries.The Wildlife Producers Association of Zambia. CJT was funded with a Claude Leon Fellowship.http://www.plosone.orgam201
Underperformance of African protected area networks and the case for new conservation models : insights from Zambia
Many African protected areas (PAs) are not functioning effectively. We reviewed the performance of Zambia’s PA network
and provide insights into how their effectiveness might be improved. Zambia’s PAs are under-performing in ecological,
economic and social terms. Reasons include: a) rapidly expanding human populations, poverty and open-access systems in
Game Management Areas (GMAs) resulting in widespread bushmeat poaching and habitat encroachment; b) underfunding
of the Zambia Wildlife Authority (ZAWA) resulting in inadequate law enforcement; c) reliance of ZAWA on extracting
revenues from GMAs to cover operational costs which has prevented proper devolution of user-rights over wildlife to
communities; d) on-going marginalization of communities from legal benefits from wildlife; e) under-development of the
photo-tourism industry with the effect that earnings are limited to a fraction of the PA network; f) unfavourable terms and
corruption which discourage good practice and adequate investment by hunting operators in GMAs; g) blurred
responsibilities regarding anti-poaching in GMAs resulting in under-investment by all stakeholders. The combined effect of
these challenges has been a major reduction in wildlife densities in most PAs and the loss of habitat in GMAs. Wildlife fares
better in areas with investment from the private and/or NGO sector and where human settlement is absent. There is a need
for: elevated government funding for ZAWA; greater international donor investment in protected area management; a shift
in the role of ZAWA such that they focus primarily on national parks while facilitating the development of wildlife-based
land uses by other stakeholders elsewhere; and new models for the functioning of GMAs based on joint-ventures between
communities and the private and/or NGO sector. Such joint-ventures should provide defined communities with ownership
of land, user-rights over wildlife and aim to attract long-term private/donor investment. These recommendations are
relevant for many of the under-funded PAs occurring in other African countries.The Wildlife Producers Association of Zambia. CJT was funded with a Claude Leon Fellowship.http://www.plosone.orgam201
Evidence of fatal skeletal injuries on Malapa Hominins 1 and 2
Malapa is one of the richest early hominin sites in Africa and the discovery site of the hominin
species, Australopithecus sediba. The holotype and paratype (Malapa Hominin 1 and 2, or MH1 and
MH2, respectively) skeletons are among the most complete in the early hominin record. Dating to
approximately two million years BP, MH1 and MH2 are hypothesized to have fallen into a natural pit
trap. All fractures evident on MH1 and MH2 skeletons were evaluated and separated based on wet
and dry bone fracture morphology/characteristics. Most observed fractures are post-depositional, but
those in the right upper limb of the adult hominin strongly indicate active resistance to an impact,
while those in the juvenile hominin mandible are consistent with a blow to the face. The presence of
skeletal trauma independently supports the falling hypothesis and supplies the first evidence for the
manner of death of an australopith in the fossil record that is not attributed to predation or natural
death.The National Research Foundation of South Africa (NRF)http://www.nature.com/scientificreportsam201
Two-pion Bose-Einstein correlations in central Pb-Pb collisions at = 2.76 TeV
The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb
collisions at TeV at the Large Hadron Collider is
presented. We observe a growing trend with energy now not only for the
longitudinal and the outward but also for the sideward pion source radius. The
pion homogeneity volume and the decoupling time are significantly larger than
those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/388
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