9,289 research outputs found
Cities as emergent models: the morphological logic of Manhattan and Barcelona
This paper is set to unveil several particulars about the logic embedded in the diachronic model of city
growth and the rules which govern the emergence of urban spaces. The paper outlines an attempt to
detect and define the generative rules of a growing urban structure by means of evaluation techniques.
The initial approach in this regards will be to study the evolution of existing urban regions or cities which
in our case are Manhattan and Barcelona and investigate the rules and causes of their emergence and
growth. The paper will concentrate on the spatial aspect of the generative rules and investigate their
behaviour and dimensionality. Several Space Syntax evaluation methods will be implemented to capture
the change of spatial configurations within the growing urban structures. In addition, certain spatial
elements will be isolated and tested aiming to illustrate their influence on the main spatial structures.
Both urban regions were found to be emergent products of a bottom up organic growth mostly
distinguished in the vicinities of the first settlements. Despite the imposition of a uniform grid on both
cities in later stages of their development these cities managed to deform the regularity in the preplanned
grid in an emergent manner to end up with an efficient model embodied in their current spatial
arrangement. The paper reveals several consistencies in the spatial morphology of both urban regions
and provides explanation of these regularities in an approach to extract the underlying rules which
contributed to the growth optimization process
TRADE AND FOREIGN DIRECT INVESTMENT MANAGEMENT STRATEGIES FOR U.S. PROCESSED FOOD FIRMS IN CHINA
This research examines the relationship between U.S. foreign direct investment (FDI) and exports of processed foods to China and identifies management strategies to enhance U.S. competitiveness. Two-stage least-squares empirical econometric results from a simultaneous equation system indicate that there exists a strong complementary relationship between U.S exports and FDI into China. Therefore, the appropriate managerial strategy to access Chinese processed foods markets is to increase overall business activity, both FDI and exports into China.Agribusiness, International Relations/Trade,
The Bäcklund Transformations, Exact Solutions, and Conservation Laws for the Compound Modified Korteweg-de Vries-Sine-Gordon Equations which Describe Pseudospherical Surfaces
I show that the compound modified Korteweg-de Vries-Sine-Gordon equations describe pseudospherical surfaces, that is, these equations are the integrability conditions for the structural equations of such surfaces. I obtain the self-Bäcklund transformations for these equations by a geometrical method and apply the Bäcklund transformations to these solutions and generate new traveling wave solutions. Conservation laws for the latter ones are obtained using a geometrical property of these pseudospherical surfaces
Topological superconductivity of spin-3/2 carriers in a three-dimensional doped Luttinger semimetal
We investigate topological Cooper pairing, including gapless Weyl and fully
gapped class DIII superconductivity, in a three-dimensional doped Luttinger
semimetal. The latter describes effective spin-3/2 carriers near a quadratic
band touching and captures the normal-state properties of the 227 pyrochlore
iridates and half-Heusler alloys. Electron-electron interactions may favor
non--wave pairing in such systems, including even-parity -wave pairing.
We argue that the lowest energy -wave pairings are always of complex (e.g.,
) type, with nodal Weyl quasiparticles. This implies scaling of the density of states (DoS) at low energies in the clean
limit, or over a wide critical region in the presence of
disorder. The latter is consistent with the -dependence of the penetration
depth in the half-Heusler compound YPtBi. We enumerate routes for experimental
verification, including specific heat, thermal conductivity, NMR relaxation
time, and topological Fermi arcs. Nucleation of any -wave pairing also
causes a small lattice distortion and induces an -wave component; this gives
a route to strain-engineer exotic pairings. We also consider odd-parity,
fully gapped -wave superconductivity. For hole doping, a gapless Majorana
fluid with cubic dispersion appears at the surface. We invent a generalized
surface model with -fold dispersion to simulate a bulk with winding number
. Using exact diagonalization, we show that disorder drives the surface
into a critically delocalized phase, with universal DoS and multifractal
scaling consistent with the conformal field theory (CFT) SO(), where
counts replicas. This is contrary to the naive expectation of
a surface thermal metal, and implies that the topology tunes the surface
renormalization group to the CFT in the presence of disorder.Comment: Published Version in PRB (Editors' Suggestion): 49 Pages, 17 Figures,
3 Table
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