Inferences from prior-based loss functions

Inferences that arise from loss functions determined by the prior are considered and it is shown that these lead to limiting Bayes rules that are closely connected with likelihood. The procedures obtained via these loss functions are invariant under reparameterizations and are Bayesian unbiased or limits of Bayesian unbiased inferences. These inferences serve as well-supported alternatives to MAP-based inferences

Invariant PP-values for model checking

$P$-values have been the focus of considerable criticism based on various considerations. Still, the $P$-value represents one of the most commonly used statistical tools. When assessing the suitability of a single hypothesized distribution, it is not clear that there is a better choice for a measure of surprise. This paper is concerned with the definition of appropriate model-based $P$-values for model checking.Comment: Published in at http://dx.doi.org/10.1214/09-AOS727 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Grain-size dependence of plastic deformation in nanocrystalline Fe

Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The article originally appeared in Journal of Applied Physics 93, 9282 (2003) and may be found at http://jap.aip.org/resource/1/japiau/v93/i11/p9282_s1.Plastic deformation of nanocrystalline Fe was investigated by nanoindentation. Samples, synthesized by mechanical attrition, consisted of powder particles with diameters greater than 30 μm. The average grain diameters within the particles of different samples ranged from 10 nm to 10 μm. To avoid potential artifacts, samples were prepared without use of heat treatment, and measurements were conducted at a depth significantly smaller than the powder particle size. Corrections were made for the indentation-size effect and for pileup or sink in around the indent. The volume-averaged grain size was used in the analysis. The Hall-Petch relation is obeyed for grain sizes above about 18 nm, and slight softening occurs at smaller grain sizes. The strain-rate sensitivity increases monotonically with decreasing grain size. The results are consistent with grain-boundary sliding. © 2003 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70350/2/JAPIAU-93-11-9282-1.pd

Grain-boundary relaxation and its effect on plasticity in nanocrystalline Fe

The article originally appeared in Journal of Applied Physics 99, 083504 (2006) and may also be found at http://jap.aip.org/resource/1/japiau/v93/i11/p9287_s1Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83389/1/Jang_JAP_2006.pd

Unilateral vs. Bilateral Incentives: Evidence from the U.S. Pork Industry

The idea that individuals adapt their behaviors in response to changes in incentive systems is fundamental to most economic analysis. This paper incorporates the concept of price discovery costs into the incentive theory to offer a theoretical model and empirical evidence on the differential incentive effects of long-term contracts and spot markets. Using the US pork industry case where procuring intertemporally consistent weights of hogs have been critical to pork processors, we show why the effectiveness of unilaterally determined and posted incentive price for the hog quality by the pork packers on the intertemporal consistency erodes and why a bilateral incentive structure built through long-term hog procurement contracts is demanded, in the presence of volatile hog price and feed price movements. The MGARCH model analysis of USDA AMS data supported our hypotheses that long-term hog procurement contracts would help moderate the erosion relative to the spot markets, resulting greater intertemporal consistency of hog weights.long-term contracts, incentive effects, price discovery costs, MGARCH model, Livestock Production/Industries,

Weak Informativity and the Information in One Prior Relative to Another

A question of some interest is how to characterize the amount of information that a prior puts into a statistical analysis. Rather than a general characterization, we provide an approach to characterizing the amount of information a prior puts into an analysis, when compared to another base prior. The base prior is considered to be the prior that best reflects the current available information. Our purpose then is to characterize priors that can be used as conservative inputs to an analysis relative to the base prior. The characterization that we provide is in terms of a priori measures of prior-data conflict.Comment: Published in at http://dx.doi.org/10.1214/11-STS357 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Trade Liberalization, Heterogeneous Firms and the Soft Budget Constraint

We analyze the interaction between the soft budget constraint (SBC) and international trade by placing Segal’s (1998) SBC model within Melitz’s (2003) framework of international trade with heterogeneous monopolistically competitive firms. As in Segal’s model, SBC may result in moral hazard. The opening to international trade adds another sort of inefficiency. Some firms that would have become exporters in the absence of SBC choose to apply low effort and not export in order to extract a subsidy from the government. This effect takes place when the trade costs are sufficiently low. Overall, however, trade liberalization reduces inefficiencies generated by SBC. The number of firms subject to moral hazard SBC decreases, aggregate effort level increases and aggregate profits lost due to SBC-induced sub-optimal effort decline as trade costs decrease

Downstream Migrations of Juvenile Salmon and Other Fishes in the Upper Yukon River

The Yukon River is the fourth largest river in North America, yet the ecology of its fishes has not been well described. During the spring and summer of 2002– 04, we sampled the downstream migrations of fishes in the Yukon River mainstem near the Canada-U.S. border, using a rotary auger trap. Age-0 juvenile chinook salmon, Oncorhynchus tshawytscha, were the most common fish in the catch, and they peaked in abundance in mid-June. Smaller numbers of age-1 chinook salmon and age-0 chum salmon, O. keta, were caught earlier in the season. Over 80% of the remaining catch consisted of young-of-theyear Coregoninae (whitefish), presumably moving from natal areas to summer rearing habitats. Few adult whitefish were captured, probably because our sampling terminated before fall spawning migrations began. Both juveniles and adults were captured for six other winter or spring spawning species that we encountered. Our results indicate that the Yukon River mainstem is used extensively as a migration corridor. This reach of the mainstem has very high suspended sediment levels in summer; its significance as rearing habitat remains unknown. Further studies are required to delineate the extent of migrations and the population structure for the non-anadromous species.Le fleuve Yukon est le quatrième plus grand fleuve de l’Amérique du Nord et pourtant, l’écologie de ses poissons n’a pas été bien décrite. Au printemps et à l’été des années 2002 à 2004, nous avons échantillonné les migrations en aval des poissons du cours principal du fleuve Yukon, près de la frontière canado-américaine et ce, à l’aide d’un piège rotatif. Le saumon quinnat d’âge 0-juvénile, Oncorhynchus tshawytscha, était le poisson le plus souvent capturé, et son abondance était à son meilleur à la mi-juin. De plus petits nombres de saumon quinnat d’âge 1 et de saumon kéta d’âge 0, O. keta, ont été attrapés au début de la saison. Plus de 80 % du reste des poissons capturés consistait en des Coregoninae (ciscos) jeunes de l’année, qui étaient sans doute en voie de déplacement, passant de leur secteur natal aux habitats d’élevage d’été. Peu de ciscos adultes ont été capturés, probablement parce que notre échantillonnage a pris fin avant les migrations de reproduction d’automne. Des poissons juvéniles et adultes ont été attrapés dans le cas de six autres espèces de reproduction d’hiver ou de printemps que nous avons rencontrées. Nos résultats indiquent que le cours principal du fleuve Yukon sert énormément de corridor de migration. Dans cette partie du cours principal, les taux de sédiments en suspension sont très élevés l’été; son importance en tant qu’habitat d’élevage demeure inconnue. Des études plus poussées s’imposent dans le but de délimiter l’étendue des migrations et la structure de population des espèces non anadromes