Does regulation reduce productivity? Evidence from regulation of the U.S. beet-sugar manufacturing industry during the Sugar Acts, 1934-74

We study the impact of regulation on productivity and welfare in the U.S. sugar manufacturing industry. While this U.S. industry has been protected from foreign competition for nearly 150 years, it was regulated only during the Sugar Act period, 1934-74. We show that regulation significantly reduced productivity, with these productivity losses leading to large welfare losses. Our initial results indicate that the welfare losses are many times larger than those typically studied ? those arising from higher prices. We also argue that the channels through which regulation led to large productivity and welfare declines in this industry were also present in many other regulated industries, like banking and trucking.Productivity ; Regulation ; Competition ; Sugar

Photorefractive incoherent-to-coherent optical converter

Photorefractive materials have been extensively used in recent years as real-time recording media for optical holography.(^1,2) One prospective application of real-time holography is in the area of optical information processing; for example, the correlation between two mutually incoherent images has recently been demonstrated in real time in a four-wave mixing geometry. (^3) Often, however, the information to be processed exists only in incoherent form. High performance spatial light modulators(^4) are thus necessary in many optical information processing systems to convert incoherent images to coherent replicas for subsequent processing. We report in this Communication the successful demonstration of real-time incoherent-to-coherent images transduction through the use of holographic recording in photorefractive crystals. Several possible configurations and experimental results are presented

A New Look at Physical Layer Security, Caching, and Wireless Energy Harvesting for Heterogeneous Ultra-dense Networks

Heterogeneous ultra-dense networks enable ultra-high data rates and ultra-low latency through the use of dense sub-6 GHz and millimeter wave (mmWave) small cells with different antenna configurations. Existing work has widely studied spectral and energy efficiency in such networks and shown that high spectral and energy efficiency can be achieved. This article investigates the benefits of heterogeneous ultra-dense network architecture from the perspectives of three promising technologies, i.e., physical layer security, caching, and wireless energy harvesting, and provides enthusiastic outlook towards application of these technologies in heterogeneous ultra-dense networks. Based on the rationale of each technology, opportunities and challenges are identified to advance the research in this emerging network.Comment: Accepted to appear in IEEE Communications Magazin

PRODUCT CHARACTERISTICS AFFECTING CONSUMERS' FRESH BEEF CUT PURCHASING DECISIONS IN THE UNITED STATES, JAPAN, AND AUSTRALIA

The effects of product and economic characteristics on consumers who purchase six cuts of fresh beef (blocks/parts, steak, thinly sliced, diced, chopped, and ground) in urban areas of the United States, Japan, and Australia will be examined in this paper. Certain product characteristics (such as product freshness and display case cleanliness) were important to consumers of beef in all three countries while other product characteristics (such as price considerations for ground beef consumers) were important for consumers of different beef cuts in all three countries. Some product characteristics varied in importance across consumers from different countries and consumers of different beef cuts.Consumer/Household Economics,

Evolution of pairing from weak to strong coupling on a honeycomb lattice

We study the evolution of the pairing from weak to strong coupling on a honeycomb lattice by Quantum Monte Carlo. We show numerical evidence of the BCS-BEC crossover as the coupling strength increases on a honeycomb lattice with small fermi surface by measuring a wide range of observables: double occupancy, spin susceptibility, local pair correlation, and kinetic energy. Although at low energy, the model sustains Dirac fermions, we do not find significant qualitative difference in the BCS-BEC crossover as compared to those with an extended Fermi surface, except at weak coupling, BCS regime.Comment: 5 page

Accurate and efficient structure factors in ultrasoft pseudopotential and projector augmented wave DFT

Structure factors obtained from diffraction experiments are one of the most important quantities for characterizing the electronic and structural properties of materials. Methods for calculating this quantity from plane-wave density functional theory (DFT) codes are typically prohibitively expensive to perform, requiring the electron density to be constructed and evaluated on dense real-space grids. Making use of the projector functions found in both the Vanderbilt ultrasoft pseudopotential and projector augmented wave methods, we implement an approach to calculate structure factors that avoids the use of a dense grid by separating the rapidly changing contributions to the electron density and treating them on logarithmic radial grids. This approach is successfully validated against structure factors obtained from all-electron DFT and experiment for three prototype systems, allowing structure factors to be obtained at all-electron accuracy at a fraction of the cost of previous approaches for plane-wave DFT

NMR relaxation studies of electronic structure in NbSe3

NMR spin-lattice relaxation measurements of the Nb93 resonance for each Nb site were performed on an aligned, multicrystalline NbSe3 sample at different temperatures. Results are associated with local electron densities of states for each of the three crystallographic sites, demonstrating Fermi-surface changes associated with the two charge-density-wave phase transitions. The most significant Fermi-surface changes occur for the yellow and orange crystallographic sites, at the high- and low-temperature phase transitions, respectively. The third site, however, is found to be noninsulating. A comparison is made to band theory and other experimental results

Hecke algebras with unequal parameters and Vogan's left cell invariants

In 1979, Vogan introduced a generalised $\\tau$ -invariant for characterising primitive ideals in enveloping algebras. Via a known dictionary this translates to an invariant of left cells in the sense of Kazhdan and Lusztig. Although it is not a complete invariant, it is extremely useful in describing left cells. Here, we propose a general framework for defining such invariants which also applies to Hecke algebras with unequal parameters.Comment: 15 pages. arXiv admin note: substantial text overlap with arXiv:1405.573

A unified constitutive model for asymmetric tension and compression creep-ageing behaviour of naturally aged Al-Cu-Li alloy

A set of unified constitutive equations is presented that predict the asymmetric tension and compression creep behaviour and recently observed double primary creep of pre-stretched/naturally aged aluminium-cooper-lithium alloy AA2050-T34. The evolution of the primary micro- and macro-variables related to the precipitation hardening and creep deformation of the alloy during creep age forming (CAF) are analysed and modelled. Equations for the yield strength evolution of the alloy, including an initial reversion and subsequent strengthening, are proposed based on a theory of concurrent dissolution, re-nucleation and growth of precipitates during artificial ageing. We present new observations of so-called double primary creep during the CAF process. This phenomenon is then predicted by introducing effects of interacting microstructures, including evolving precipitates, diffusing solutes and dislocations, into the sinh-law creep model. In addition, concepts of threshold creep stress σth and a microstructure-dependant creep variable H, which behave differently under different external stress directions, are proposed and incorporated into the creep model. This enables prediction of the asymmetric tension and compression creep-ageing behaviour of the alloy. Quantitative transmission electron microscopy (TEM) and related small-angle X-ray scattering (SAXS) analysis have been carried out for selected creep-aged samples to assist the development and calibration of the constitutive model. A good agreement has been achieved between the experimental results and the model. The model has the potential to be applied to creep age forming of other heat-treatable aluminium alloys