To Review or Not to Review? Limited Strategic Thinking at the Movie Box Office

Film distributors occasionally withhold movies from critics before their release. Cold openings provide a natural field setting to test models of limited strategic thinking. In a set of 856 widely released movies, cold opening produces a significant 15% increase in domestic box office revenue (though not in foreign markets and DVD sales), consistent with the hypothesis that some moviegoers do not infer low quality from cold opening. Structural parameter estimates indicate 1–2 steps of strategic thinking by moviegoers (comparable to experimental estimates). However, movie studios appear to think moviegoers are sophisticated since only 7% of movies are opened cold

Relaxed Schedulers Can Efficiently Parallelize Iterative Algorithms

There has been significant progress in understanding the parallelism inherent to iterative sequential algorithms: for many classic algorithms, the depth of the dependence structure is now well understood, and scheduling techniques have been developed to exploit this shallow dependence structure for efficient parallel implementations. A related, applied research strand has studied methods by which certain iterative task-based algorithms can be efficiently parallelized via relaxed concurrent priority schedulers. These allow for high concurrency when inserting and removing tasks, at the cost of executing superfluous work due to the relaxed semantics of the scheduler. In this work, we take a step towards unifying these two research directions, by showing that there exists a family of relaxed priority schedulers that can efficiently and deterministically execute classic iterative algorithms such as greedy maximal independent set (MIS) and matching. Our primary result shows that, given a randomized scheduler with an expected relaxation factor of $k$ in terms of the maximum allowed priority inversions on a task, and any graph on $n$ vertices, the scheduler is able to execute greedy MIS with only an additive factor of poly($k$) expected additional iterations compared to an exact (but not scalable) scheduler. This counter-intuitive result demonstrates that the overhead of relaxation when computing MIS is not dependent on the input size or structure of the input graph. Experimental results show that this overhead can be clearly offset by the gain in performance due to the highly scalable scheduler. In sum, we present an efficient method to deterministically parallelize iterative sequential algorithms, with provable runtime guarantees in terms of the number of executed tasks to completion.Comment: PODC 2018, pages 377-386 in proceeding

Fault-tolerant error correction with the gauge color code

The constituent parts of a quantum computer are inherently vulnerable to errors. To this end we have developed quantum error-correcting codes to protect quantum information from noise. However, discovering codes that are capable of a universal set of computational operations with the minimal cost in quantum resources remains an important and ongoing challenge. One proposal of significant recent interest is the gauge color code. Notably, this code may offer a reduced resource cost over other well-studied fault-tolerant architectures using a new method, known as gauge fixing, for performing the non-Clifford logical operations that are essential for universal quantum computation. Here we examine the gauge color code when it is subject to noise. Specifically we make use of single-shot error correction to develop a simple decoding algorithm for the gauge color code, and we numerically analyse its performance. Remarkably, we find threshold error rates comparable to those of other leading proposals. Our results thus provide encouraging preliminary data of a comparative study between the gauge color code and other promising computational architectures.Comment: v1 - 5+4 pages, 11 figures, comments welcome; v2 - minor revisions, new supplemental including a discussion on correlated errors and details on threshold calculations; v3 - Author accepted manuscript. Accepted on 21/06/16. Deposited on 29/07/16. 9+5 pages, 17 figures, new version includes resource scaling analysis in below threshold regime, see eqn. (4) and methods sectio

Canavanine-induced longevity in mice may require diets with greater than 15.7% protein

BACKGROUND: Dietary administration of 1% canavanine had been shown to improve survival in female BALB/c mice consuming diets containing 23.4% protein (dry matter basis). METHODS: In order to determine if this effect also obtains at more moderate dietary protein concentrations, 30 female BALB/c mice were fed a basal diet with 14% protein (15.7% dry matter basis) and another 30 were fed the same diet plus 1% canavanine. RESULTS: Neither mean (Control 873.2 d, Canavanine 870.0 d; SEM = 34.2 d; P = 0.949 from ANOVA) nor median (Control 902 d, Canavanine 884.5 d; P = 0.9058 from Mann-Whitney) lifespans differed between groups. Although mean antinuclear antibody (ANA) titers did not differ between control and canavanine-treated mice at 833 days of age (19.84 vs 20.39 respectively; SEM = 2.64; P = 0.889 from ANOVA), one canavanine-treated mouse displayed an outlying ANA value of 50 (next lower value = 30) denoting possible early sign of incipient autoimmune disease in that individual. CONCLUSION: There may be an interaction between dietary protein level and canavanine with respect to lifespan in mice

Estimating genetic parameters in commercial beef cattle populations

The data used in this study were the Tennessee Beef Cattle Improvement Program weaning records of 18,393 Angus and Hereford calves accumulated over the nine year period, 1964 through 1972. The calves were classified according to weaning age (within the range of 120 to 300 days inclusive), sex (bulls, heifers, steers), age of dam (by years from two to 10 years inclusive and 11 years and over), month of birth, management (creep or non-creep fed), year and breed in preliminary analyses. The purpose of this study was to determine the effect of various methods of adjusting weaning weight for environmental variation and various methods of calculating genetic parameters on the magnitude of these estimates. Nine combinations of four methods of adjusting weaning weight to an age-constant basis and four methods of adjusting age-constant weights fixed environmental effects were used to generate nine sets of adjusted weights. A nested analysis of variance procedure was used to analyze the nine sets of adjusted 205-day weights and weaning type score and to produce variance and covariance components to be used in estimating heritability parameters for the traits in question. It was determined by Barlett\u27s Test for Homogeneity of Variances that the records of Angus and Hereford calves could be combined in a single analysis. However, the residual mean squares of creep and non-creep fed calves were heterogeneous and in all final analyses the two management groups were analyzed separately. Sire and herd were found to significantly effect (P \u3c .01) both weaning weight and weaning type score. The effect of herd had a tremendously pronounced effect upon both traits regardless of the management group (creep or non-creep fed). Estimates of heritability and genetic correlations were calculated from components of variance by two different methods—inter-herd and intra-herd. The intra-herd estimates were calculated by the standard paternal half-sib methods. The inter-herd estimate was calculated by adding the component of variance of herd within year to the denominator of the standard paternal half-sib formulas for calculating heritability and genetic correlation. Estimates of heritability calculated by the inter-herd method were similar to those reported in other studies when the estimates were calculated from commercial herds. The mean estimate of heritability for adjusted 205-day weight (average of nine methods of adjusting) was .424 and the estimate for weaning type score was .401 in non-creep calves. The estimates were .343 and .293 respectively, in creep-fed calves. Estimates in both management groups tended to be higher than those reported for experimental herds. The estimates calculated on an inter-herd basis tended to be closer to the estimates reported for these traits which were determined in experimental herds. The estimates for 205-day weight (average value) and weaning type score were .288 and .298, respectively, in non-creep calves and .177 and .180, respectively, in creep-fed calves. Genetic correlations between weaning type score and adjusted 205-day weight were positive and fairly large in magnitude. The inter-herd method tended to increase the genetic correlations between different methods of correcting weaning weight in both the non-creep and the creep-fed calves. However, the intra-herd correlations between the traits (weaning type score and adjusted 205-day weight) were higher for non-creep-fed calves than were the inter-herd correlations. Comparison of these results with estimates derived in experimental herds suggests that the component of variance for herd in a nested analysis of variance contains both genetic and environmental variation. The true estimates of the genetic parameters probably lie somewhere between the intra-herd and the inter-herd estimates calculated in this study

An analysis of the genetic implications of maternal and grandmaternal effects in beef cattle selection programs

A study utilizing 3,220 performance records of Angus calves dropped over a 19-year period from 1957 to 1975 was undertaken in an attempt to estimate the importance of direct, maternal, and grandmaternal variances and to evaluate their interrelationship as causative factors in creating phenotypic variation in birth weight, gain from birth to weaning, weaning condition, and weaning weights. All of these records were obtained from cattle at the Ames Plantation in Tennessee and were from non-creep-fed calves. The data were adjusted by least squares procedures for the effects of year of birth, season of birth, and age of dam. These adjusted data were used to calculate the various covariances among relatives. The model for maternal effects utilized the covariances of the individual with itself and paternal half-sibs, maternal half-sibs, full-sibs, dam-offspring, and granddam offspring covariances. While the model for assessing grandmaternal genetic influences utilized, in addition to the above six, covariances between cousins, within cousins, and within paternal half-sibs. All of these were equated to their expected biological components, direct genetic variance, maternal genetic variance, grandmaternal genetic variance, covariances between direct and maternal, between direct and grandmaternal, between maternal and grandmaternal, direct environmental variance, maternal environmental variance, and the covariance between direct and maternal environmental effects. The maternal model yielded positive effects for all estimates of variances with the direct environmental variance contributing the largest fraction of the total phenotypic variances for all traits except adjusted weaning weight (6.6%). The estimates ranged quite high (up to 83.4% for birth weight); however, the heritability estimates are in line with accepted values for these traits. The direct estimates of variance, ranging from a low of 16.1% for weaning condition to a high of 41.5% for weaning weight, were, therefore, considered quite reasonable. Estimates of the maternal variance all tended to be low (from 1.4% to 4.5%); however, they are positive and do exist. The covariance between direct and maternal effects and the environmental covariances between direct and maternal effects exhibited negative signs except for the genetic covariance for birth weight (7.4% and 6.1%) and environmental covariance for weaning condition (16.4% and 17.0%). This negative covariance supports the theory of an antagonism existing between direct and maternal effects for the weaning and preweaning traits. The grandmaternal model showed the variance estimates for all effects to be positive except adjusted weaning weight and adjusted gain (-1.2 and -1.2) for the maternal environmental variance. These estimates ranged from 20.2% for birth to 42.8% for weaning weight for direct effects, while the maternal variances were in the 6% to 16% range as to their influence upon the total phenotypic variance. The estimates of the grandmaternal variance were in the range of 5% to 10%, thus very evident as to their importance upon the total phenotypic variance. The estimates for grandmaternal genetic variance were all fairly large in magnitude and were thought to play an important role in validating the alternate generation phenomenon