Analysis of an information-theoretic model for communication

We study the cost-minimization problem posed by Ferrer i Cancho and Sol\'e in their model of communication that aimed at explaining the origin of Zipf's law [PNAS 100, 788 (2003)]. Direct analysis shows that the minimum cost is $\min {\lambda, 1-\lambda}$, where $\lambda$ determines the relative weights of speaker's and hearer's costs in the total, as shown in several previous works using different approaches. The nature and multiplicity of the minimizing solution changes discontinuously at $\lambda=1/2$, being qualitatively different for $\lambda 1/2$, and $\lambda=1/2$. Zipf's law is found only in a vanishing fraction of the minimum-cost solutions at $\lambda = 1/2$ and therefore is not explained by this model. Imposing the further condition of equal costs yields distributions substantially closer to Zipf's law, but significant differences persist. We also investigate the solutions reached by the previously used minimization algorithm and find that they correctly recover global minimum states at the transition.Comment: 19 pages, 4 figures. Important references and new results adde

Production and carcass traits of high dairy genetic merit Holstein, standard dairy genetic merit Friesian and Charolais × Holstein-Friesian male cattle

peer-reviewedThe increased proportion of Holstein genetic material in the dairy herd has consequences for beef production in Ireland. A total of 72 spring-born male calves (24 Holsteins (HO), 24 Friesian (FR) and 24 Charolais × Holstein-Friesians (CH)) were reared from calfhood to slaughter. Calves were artificially reared indoors and spent their first summer at pasture following which they were assigned, on a breed basis, to a factorial combination of two production systems (intensive 19-month bull beef and extensive 25-month steer beef) and two slaughter weights (560 and 650 kg). After slaughter the pistola hind quarter was separated into fat, bone and muscle. Live-weight gain, carcass gain, kill-out proportion, carcass conformation and carcass fat scores were 830, 811 and 859 (s.e. 14.9) g/day, 540, 533, 585 (s.e. 7.7) g/day, 526, 538 and 561 (s.e. 3.0) g/kg, 1.51, 2.18 and 2.96 (s.e. 0.085), and 3.40, 4.25 and 4.06 (s.e. 0.104) for HO, FR and CH, respectively. Corresponding values for pistola weight as a proportion of carcass weight, pistola muscle proportion and pistola fat proportion were 458, 459 and 461 (s.e. 2.6) g/kg, 657, 645 and 667 (s.e. 3.7) g/kg, and 132, 161 and 145 (s.e. 4.1) g/kg. Compared with the intensive system, animals on the extensive system had a lower (P < 0.001) daily live-weight gain, kill-out proportion and a lower muscle proportion in the pistola. Increasing slaughter weight increased (P < 0.001) carcass weight and carcass fat score and reduced the proportion of muscle in the pistola. Allometric regression coefficients for pistola weight on side weight, and total bone, muscle and fat weights on pistola weight were 0.898, 0.755, 0.900 and 1.910 respectively. It is concluded that HO grew at least as fast as FR but had a lower killout proportion. Carcass conformation and fat scores were greater for FR than for HO and muscle proportion in the pistola was lower and total fat proportion was higher. Compared with FR, CH had heavier carcasses, a higher kill-out proportion and less fat and more muscle in the pistola

Body and carcass measurements, carcass conformation and tissue distribution of high dairy genetic merit Holstein, standard dairy genetic merit Friesian and Charolais x Holstein-Friesian male cattle

peer-reviewedThe increased proportion of Holstein genes in the dairy herd may have undesirable consequences for beef production in Ireland. A total of 72 spring-born calves, (24 Holstein (HO), 24 Friesian (FR) and 24 Charolais X Holstein-Friesian (CH)) were reared from calfhood to slaughter. Calves were artificially reared indoors and spent their first summer at pasture following which they were assigned to a 3 breeds (HO, FR and CH) 2 production systems (intensive 19-month bull beef and extensive 25-month steer beef) 2 slaughter weights (560 and 650 kg) factorial experiment. Body measurements of all animals were recorded at the same time before the earliest slaughter date. After slaughter, carcasses were graded and measured and the pistola hind-quarter was separated into fat, bone and muscle. HO had significantly higher values for withers height, pelvic height and chest depth than FR, which in turn had higher values than CH. HO had a longer back and a narrower chest than either FR or CH, which were not significantly different. Carcass length and depth, pistola length, and leg length were 139.2, 134.4 and 132.0 (s.e. 0.81), 52.1, 51.3 and 47.7 (s.e. 0.38), 114.4, 109.0 and 107.0 (s.e. 0.65) and 76.7, 71.9 and 71.4 (s.e. 0.44) cm for HO, FR and CH, respectively. Breed differences in pistola tissue distribution between the joints were small and confined to the distal pelvic limb and ribs. There were relatively small breed differences in the distribution of pistola muscle weight between individual muscles. Body measurements were significantly greater for animals on the intensive system (bulls) than the extensive system (steers) in absolute terms, but the opposite was so when they were expressed relative to live weight. The only significant difference in relative carcass measurements between the production systems was for carcass depth, which was lower for the intensive compared with the extensive system. Increasing slaughter weight significantly increased all carcass measurements in absolute terms but reduced them relative to weight. It is concluded that there were large differences between the breed types in body and carcass measurements, and hence in carcass shape and compactness but differences in tissue distribution were small

Design of Farthest-Point Masks for Image Halftoning

In an earlier paper, we briefly presented a new halftoning algorithm called farthest-point halftoning. In the present paper, this method is analyzed in detail, and a novel dispersion measure is defined to improve the simplicity and flexibility of the result. This new stochastic screen algorithm is loosely based on Kang's dispersed-dot ordered dither halftone array construction technique used as part of his microcluster halftoning method. Our new halftoning algorithm uses pixelwise measures of dispersion based on one proposed by Kang which is here modified to be more effective. In addition, our method exploits the concept of farthest-point sampling (FPS), introduced as a progressive irregular sampling method by Eldar et al. but uses a more efficient implementation of FPS in the construction of the dot profiles. The technique we propose is compared to other state-of-the-art dither-based halftoning methods in both qualitative and quantitative manners

Non-carcass parts and carcass composition of high dairy genetic merit Holstein, standard dairy genetic merit Friesian and Charolais × Holstein-Friesian steers

peer-reviewedThe increased use of Holstein genetic material in the dairy herd has consequences for beef production. A total of 24 spring-born calves comprising 8 Holsteins (HO), 8 Friesians (FR) and 8 Charolais × Holstein-Friesians (CH) were reared from calfhood to slaughter. At the end of the second grazing season they were assigned to a 3 (breeds; HO, FR and CH) × 2 (slaughter weights; 620 and 730 kg) factorial experiment and fin¬ished indoors. After slaughter carcasses were classified for conformation and fatness, all organs and non-carcass parts were weighed, and the right side of each carcass was dissected into fat, bone and muscle. Non-carcass parts, carcass weight, kill-out propor¬tion, carcass conformation score and m. longissimus area were 405, 398 and 368 (s.e. 8.31) g/kg empty body weight, 355, 344 and 383 (s.e. 9.4) kg, 509, 520 and 545 (s.e. 8.99) g/kg, 1.0, 2.0 and 3.1 (s.e. 0.16), 7616, 7096 and 9286 (s.e. 223.4) mm2 for HO, FR and CH, respectively. Corresponding proportions of carcass muscle and fat were 631, 614 and 656 (s.e. 8.4), and 165, 200 and 165 (s.e. 10.5) g/kg. Increasing slaughter weight increased the proportion of total non-carcass parts, carcass weight, carcass fat score and fat proportion, and reduced carcass muscle and bone proportions. It is concluded that differences in kill-out proportion between the two dairy breeds was primarily due to the lower proportion of gastrointestinal tract (GIT) in FR, and the higher kill-out proportion of CH was mainly due to lower proportions of GIT, internal organs and internal fat. In terms of beef production, HO and FR were broadly comparable for most traits except carcass conformation score and carcass fat proportion, which were lower for HO. CH was superior to the dairy breeds in all important production traits

Origin of the approximate universality of distributions in equilibrium correlated systems

We propose an interpretation of previous experimental and numerical experiments, showing that for a large class of systems, distributions of global quantities are similar to a distribution originally obtained for the magnetization in the 2D-XY model . This approach, developed for the Ising model, is based on previous numerical observations. We obtain an effective action using a perturbative method, which successfully describes the order parameter fluctuations near the phase transition. This leads to a direct link between the D-dimensional Ising model and the XY model in the same dimension, which appears to be a generic feature of many equilibrium critical systems and which is at the heart of the above observations.Comment: To appear in Europhysics Letter

Ginzburg-Landau equation bound to the metal-dielectric interface and transverse nonlinear optics with amplified plasmon polaritons

Using a multiple-scale asymptotic approach, we have derived the complex cubic Ginzburg-Landau equation for amplified and nonlinearly saturated surface plasmon polaritons propagating and diffracting along a metal-dielectric interface. An important feature of our method is that it explicitly accounts for nonlinear terms in the boundary conditions, which are critical for a correct description of nonlinear surface waves. Using our model we have analyzed filamentation and discussed bright and dark spatially localized structures of plasmons.Comment: http://link.aps.org/doi/10.1103/PhysRevA.81.03385

Extreme statistics for time series: Distribution of the maximum relative to the initial value

The extreme statistics of time signals is studied when the maximum is measured from the initial value. In the case of independent, identically distributed (iid) variables, we classify the limiting distribution of the maximum according to the properties of the parent distribution from which the variables are drawn. Then we turn to correlated periodic Gaussian signals with a 1/f^alpha power spectrum and study the distribution of the maximum relative height with respect to the initial height (MRH_I). The exact MRH_I distribution is derived for alpha=0 (iid variables), alpha=2 (random walk), alpha=4 (random acceleration), and alpha=infinity (single sinusoidal mode). For other, intermediate values of alpha, the distribution is determined from simulations. We find that the MRH_I distribution is markedly different from the previously studied distribution of the maximum height relative to the average height for all alpha. The two main distinguishing features of the MRH_I distribution are the much larger weight for small relative heights and the divergence at zero height for alpha>3. We also demonstrate that the boundary conditions affect the shape of the distribution by presenting exact results for some non-periodic boundary conditions. Finally, we show that, for signals arising from time-translationally invariant distributions, the density of near extreme states is the same as the MRH_I distribution. This is used in developing a scaling theory for the threshold singularities of the two distributions.Comment: 29 pages, 4 figure

Renormalization group theory for finite-size scaling in extreme statistics

We present a renormalization group (RG) approach to explain universal features of extreme statistics, applied here to independent, identically distributed variables. The outlines of the theory have been described in a previous Letter, the main result being that finite-size shape corrections to the limit distribution can be obtained from a linearization of the RG transformation near a fixed point, leading to the computation of stable perturbations as eigenfunctions. Here we show details of the RG theory which exhibit remarkable similarities to the RG known in statistical physics. Besides the fixed points explaining universality, and the least stable eigendirections accounting for convergence rates and shape corrections, the similarities include marginally stable perturbations which turn out to be generic for the Fisher-Tippett-Gumbel class. Distribution functions containing unstable perturbations are also considered. We find that, after a transitory divergence, they return to the universal fixed line at the same or at a different point depending on the type of perturbation.Comment: 15 pages, 8 figures, to appear in Phys. Rev.

Lipid Oxidation and Sensory Characteristics of Grass-Fed Beef: Effect of Duration of Grazing Prior to Slaughter

Beef from cattle produced from grass has a higher concentration of fatty acids considered to be beneficial to human health than beef produced from more intensive production systems and this increase in fatty acid concentration is dependant on the duration at pasture prior to slaughter (Noci et al., 2003). Improvements in the fatty acid composition of beef must not impair other quality characteristics of beef. Little information is available on the pattern of change of quality characteristics in grazing animals. The objective of this study was to determine the shelf-life and eating quality of beef from cattle produced from a standard Irish grass silage/concentrates finishing system but allowed to graze grass for different periods prior to slaughter