11,272 research outputs found
THE SYNERGY BETWEEN SUBSECTOR COMPETITIVENESS AND REGIONAL DEVELOPMENT: THE CASE OF TURKEY AND THE TOMATO SUBSECTOR
Abstract This study develops a conceptual model of the institutions and key factors that facilitate competitiveness on the national and subsector level and then determines how linkages between the factors that enhance competitiveness and regional development can be created. Turkey and the Turkish tomato subsector provided the case to test this model.Regional development, sustainable competitiveness, tomato processing industry, Turkey, industry clusters, Community/Rural/Urban Development,
Virasoro Conformal Blocks and Thermality from Classical Background Fields
We show that in 2d CFTs at large central charge, the coupling of the stress
tensor to heavy operators can be re-absorbed by placing the CFT in a
non-trivial background metric. This leads to a more precise computation of the
Virasoro conformal blocks between heavy and light operators, which are shown to
be equivalent to global conformal blocks evaluated in the new background. We
also generalize to the case where the operators carry U(1) charges. The refined
Virasoro blocks can be used as the seed for a new Virasoro block recursion
relation expanded in the heavy-light limit. We comment on the implications of
our results for the universality of black hole thermality in , or
equivalently, the eigenstate thermalization hypothesis for at large
central charge.Comment: 27+7 pages, 3 figures; typos corrected, citations adde
Universality of Long-Distance AdS Physics from the CFT Bootstrap
We begin by explicating a recent proof of the cluster decomposition principle
in AdS_{d+1} from the CFT_d bootstrap in d > 2. The CFT argument also computes
the leading interactions between distant objects in AdS, and we confirm the
universal agreement between the CFT bootstrap and AdS gravity in the
semi-classical limit. We proceed to study the generalization to 2d CFTs, which
requires knowledge of the Virasoro conformal blocks in a lightcone OPE limit.
We compute these blocks in a semiclassical, large central charge approximation,
and use them to prove a suitably modified theorem. In particular, from the 2d
bootstrap we prove the existence of large spin operators with fixed 'anomalous
dimensions' indicative of the presence of deficit angles in AdS_3. As we
approach the threshold for the BTZ black hole, interpreted as a CFT scaling
dimension, the twist spectrum of large spin operators becomes dense. Due to the
exchange of the Virasoro identity block, primary states above the BTZ threshold
mimic a thermal background for light operators. We derive the BTZ quasi-normal
modes, and we use the bootstrap equation to prove that the twist spectrum is
dense. Corrections to thermality could be obtained from a more refined
computation of the Virasoro conformal blocks.Comment: 34+31 pages, references added, typo in higher-dimensional energy
shift corrected, discussion of coefficient density bounds expande
Nonperturbative Matching Between Equal-Time and Lightcone Quantization
We investigate the nonperturbative relation between lightcone (LC) and
standard equal-time (ET) quantization in the context of theory
in . We discuss the perturbative matching between bare parameters and the
failure of its naive nonperturbative extension. We argue that they are
nevertheless the same theory nonperturbatively, and that furthermore the
nonperturbative map between bare parameters can be extracted from ET
perturbation theory via Borel resummation of the mass gap. We test this map by
using it to compare physical quantities computed using numerical Hamiltonian
truncation methods in ET and LC.Comment: 22+8 pages, 10 figure
Eikonalization of Conformal Blocks
Classical field configurations such as the Coulomb potential and
Schwarzschild solution are built from the t-channel exchange of many light
degrees of freedom. We study the CFT analog of this phenomenon, which we term
the `eikonalization' of conformal blocks. We show that when an operator
appears in the OPE , then the large spin
Fock space states also appear in this OPE with a
computable coefficient. The sum over the exchange of these Fock space states in
an correlator
build the classical ` field' in the dual AdS description. In some limits the
sum of all Fock space exchanges can be represented as the exponential of a
single exchange in the 4-pt correlator of . Our results should
be useful for systematizing perturbation theory in general CFTs and
simplifying the computation of large spin OPE coefficients. As examples we
obtain the leading dependence of Fock space conformal block
coefficients, and we directly compute the OPE coefficients of the simplest
`triple-trace' operators.Comment: 32+17 pages, 6 figures; references added, discussion of eikonal limit
clarifie
Hawking from Catalan
The Virasoro algebra determines all `graviton' matrix elements in
AdS/CFT. We study the explicit exchange of any number of Virasoro
gravitons between heavy and light CFT operators at large central charge.
These graviton exchanges can be written in terms of new on-shell tree diagrams,
organized in a perturbative expansion in , the heavy operator dimension
divided by the central charge. The Virasoro vacuum conformal block, which is
the sum of all the tree diagrams, obeys a differential recursion relation
generalizing that of the Catalan numbers. We use this recursion relation to sum
the on-shell diagrams to all orders, computing the Virasoro vacuum block.
Extrapolating to large determines the Hawking temperature of a BTZ
black hole in dual AdS theories.Comment: 19+8 pages, 5 figure
The Scrophulariaceae of Iowa
The Figwort family comprises nearly 2,500 species, which are grouped in about 165 genera. The species are quite widely distributed, but are most abundant in temperate regions, occurring rarely towards the poles and equator. Heller, in his Catalogue of North American Plants, includes 51 genera and 627 species and varieties belonging to the Figwort family. The flora of Iowa has representatives of 21 genera, there being about 45 species
The Fagaceae of Iowa
The oak family comprises five genera and 375 species. The family is of wide geographical distribution, and from an economic point of view, of very great value. Four genera occur in the United States, namely, Fagus (the Beech), Castanea (the Chestnut), Quercus (the Oak), and Castanopsis. The number of species and varieties recognized is 87. Of this number 82 belong to the genus Quercus, one each to Fagus and Castanopsis, and three to Castanea. The only genus indigenous to Iowa is Quercus, the oak, and the number of species recognized is 15
The Juglandaceae of Iowa
The walnut family comprises six genera and about 35 species. Only two genera occur in Iowa, namely, Juglans (Walnut) and Hicoria (Hickory), and these two genera are represented by two and five species respectively. From an economic point of view the species are valuable and consequently have been largely utilized until but few specimens of the older forest remain. The younger growth is hardy and will, if spared, eventually yield fair returns
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