5,845 research outputs found
Movement Restrictions, Agricultural Trade and Price Transmission between Israel and the West Bank
Imposing military security measures as a consequence of violent conflict may lead to depressing economic effects for all parties involved. One implication is the limited ability to conduct trade, which in turn brings about welfare losses to the economic agents involved and may threat livelihoods and food security. This paper focuses on the consequences of the Israeli-Palestinian conflict, as a prominent example, on bilateral agricultural trade and price dynamics. For this purpose, we consider high-frequency wholesale price data and data on movement restrictions (complete closures) which were imposed by the Israeli Defense Forces in the West Bank between May 2007 and December 2008. In particular, we study the price dynamics of cucumbers and apples, two crops which play an important role for bilateral trade. The spatial and temporal price relationships are assessed using a cointegration framework. Specifically, we use a novel multivariate exogenous regime-switching vector error correction model and employ a recently developed extension of Johansen’s cointegration estimation method. We find the wholesale markets of cucumbers and apples in Hebron and Tel Aviv to be integrated. For both products, the price differentials between both markets quickly adjust to short run deviations from the long-run price equilibria. The regime-dependent model suggests that the movement restrictions effectively cut off both markets from each other temporarily.Agricultural trade, cointegration, Israel, regime-dependent error correction, price transmission, Palestinian territories., International Relations/Trade, Marketing, Political Economy,
Superconducting Circuits for Quantum Simulation of Dynamical Gauge Fields
We describe a superconducting-circuit lattice design for the implementation
and simulation of dynamical lattice gauge theories. We illustrate our proposal
by analyzing a one-dimensional U(1) quantum-link model, where superconducting
qubits play the role of matter fields on the lattice sites and the gauge fields
are represented by two coupled microwave resonators on each link between
neighboring sites. A detailed analysis of a minimal experimental protocol for
probing the physics related to string breaking effects shows that despite the
presence of decoherence in these systems, distinctive phenomena from
condensed-matter and high-energy physics can be visualized with
state-of-the-art technology in small superconducting-circuit arrays
Tribological behaviour of polyalphaolefins: wear and rolling contact fatigue tests
Polyalphaolefin fluids are gaining rapid acceptance as high-performance lubricants and functional fluids because they have certain inherent, and highly desirable, characteristics relative to mineral oils. One of these characteristics is their low toxicity. It combined with excellent viscometrics and lubricity, have made low-viscosity PAO fluids an important component in lubricant formulations. Typical data found in product specifications for lubricants are the kinematic viscosity and the viscosity index. These values do not give enough information to choose the optimum lubricant for a lubricated contact. In mechanical systems take place rolling, sliding and rolling/sliding contacts, therefore lubricants have to work the best possible in these operation conditions. In this study are experimentally determined the L50, L10 and Weibull´s slope () of polyalphaolefins with two different viscosities. This test was made on a four-ball machine (Stanhope Seta). Wear test also was made on a four-ball tester (Roxana) in order to measure the wear scar diameter (WSD), and the flash temperature parameter (FTP). Lubricants were identified through infrared spectroscopy, and ball´s pittings were observed with SEM
Loops and Strings in a Superconducting Lattice Gauge Simulator
We propose an architecture for an analog quantum simulator of
electromagnetism in 2+1 dimensions, based on an array of superconducting
fluxonium devices. The encoding is in the integer (spin-1 representation of the
quantum link model formulation of compact U(1) lattice gauge theory. We show
how to engineer Gauss' law via an ancilla mediated gadget construction, and how
to tune between the strongly coupled and intermediately coupled regimes. The
witnesses to the existence of the predicted confining phase of the model are
provided by nonlocal order parameters from Wilson loops and disorder parameters
from 't Hooft strings. We show how to construct such operators in this model
and how to measure them nondestructively via dispersive coupling of the
fluxonium islands to a microwave cavity mode. Numerical evidence is found for
the existence of the confined phase in the ground state of the simulation
Hamiltonian on a ladder geometry.Comment: 17 pages, 5 figures. Published versio
A New Generation Gap? Some thoughts on the consequences of increasingly early ICT first contact
One possible consequence of ICT’s rapid rise will be a new ‘generation gap’ arising from differing perceptions of the learning technologies. The nature, causes and consequences of this gap are of interest to educational practitioners and policymakers.
This paper uses data from an ongoing project together with a synopsis of research to describe the ICT-based generation gap that currently exists between students and their teachers and parents. It is argued that this gap may exist between students differing in age by as little as five years.
Results from a related project exploring Networked Information and Communication Literacy Skills (NICLS), are used to introduce a discussion on the nature of any skills gap that must be addressed in the light of this generation gap
Reentrance of disorder in the anisotropic shuriken Ising model
For a material to order upon cooling is common sense. What is more seldom is
for disorder to reappear at lower temperature, which is known as reentrant
behavior. Such resurgence of disorder has been observed in a variety of
systems, ranging from Rochelle salts to nematic phases in liquid crystals.
Frustration is often a key ingredient for reentrance mechanisms. Here we shall
study a frustrated model, namely the anisotropic shuriken lattice, which offers
a natural setting to explore an extension of the notion of reentrance between
magnetic disordered phases. By tuning the anisotropy of the lattice, we open a
window in the phase diagram where magnetic disorder prevails down to zero
temperature. In this region, the competition between multiple disordered ground
states gives rise to a double crossover where both the low- and
high-temperature regimes are less correlated than the intervening classical
spin liquid. This reentrance of disorder is characterized by an entropy
plateau, a multi-step Curie law crossover and a rather complex diffuse
scattering in the static structure factor. Those results are confirmed by
complementary numerical and analytical methods: Monte Carlo simulations,
Husimi-tree calculations and an exact decoration-iteration transformation.Comment: 16 pages, 13 figure
Atomic Quantum Simulation of U(N) and SU(N) Non-Abelian Lattice Gauge Theories
Using ultracold alkaline-earth atoms in optical lattices, we construct a
quantum simulator for U(N) and SU(N) lattice gauge theories with fermionic
matter based on quantum link models. These systems share qualitative features
with QCD, including chiral symmetry breaking and restoration at non-zero
temperature or baryon density. Unlike classical simulations, a quantum
simulator does not suffer from sign problems and can address the corresponding
chiral dynamics in real time.Comment: 12 pages, 5 figures. Main text plus one basic introduction to the
topic and one supplementary material on implementation. Final versio
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