Pooling, Separating, and Cream-Skimming In Relative-Performance Contracts

Existing research on tournament-style contests suggests that mechanisms to sort contestants by ability level are unnecessary in the case of linear relative-performance contracts. This paper suggests that this result stems from uniform treatment of workers' marginal returns from effort, marginal disutilities of effort, and reservation wages. Here, we investigate relative-performance contracts with a model that allows these three factors to vary by growers' unobservable ability. Given this framework, we find that it is possible for processors to improve expected profits and total expected welfare by replacing a single contract offering meant to pool all growers with an offering of two contracts meant to separate growers by ability. Under some circumstances, a "cream-skimming" contract offering designed to attract only workers above a minimum ability level can also improve expected profits.Production Economics,

Product Quality and Grower Reputation: Dynamic Contracts With Adverse Selection

We investigate the design of a two-period contract between an agricultural processor and growers whose quality-ability types are not observable to the processor. After characterizing the optimal contracts and establishing conditions for a separating equilibrium, we investigate how a payment based on first-period reputation may induce more first-period effort. We show that this reputation-based payment can improve both the processor's and the grower's welfare, resulting in a dominant equilibrium.Agribusiness,

Pooling, Separating, and Cream-Skimming In Relative-Performance Contracts

Existing research on tournament-style contests suggests that mechanisms to sort contestants by ability level are unnecessary in the case of linear relative-performance contracts. This paper suggests that this result stems from uniform treatment of workers' marginal returns from effort, marginal disutilities of effort, and reservation wages. Here, we investigate relative-performance contracts with a model that allows these three factors to vary by growers' unobservable ability. Given this framework, we find that it is possible for processors to improve expected profits and total expected welfare by replacing a single contract offering meant to pool all growers with an offering of two contracts meant to separate growers by ability. Under some circumstances, a 'cream-skimming' contract offering designed to attract only workers above a minimum ability level can also improve expected profits.Labor and Human Capital,

SIMULATING THE IMPACTS OF CONTRACT SUPPLIES IN A SPOT MARKET-CONTRACT MARKET EQUILIBRIUM SETTING

This paper embeds a principal-agent model of producer-processor equilibrium within a market equilibrium model of contract and cash markets to analyze the impact of contracting on the spot market for hogs. The principal-agent model incorporates both quality differentiation in the contract market and an endogenously determined cash market price to account for processor-producer relationships in equilibrium. For five types of contracting scenarios, market equilibrium conditions are derived, and results are presented for a numerical example. Contrary to previous results, the paper finds that the increased supply of hogs under typical formula-price contracts can increase the cash market price and reduce its variance.Marketing,

Overexpression of Class III β-tubulin, Sox2, and nuclear Survivin is predictive of taxane resistance in patients with stage III ovarian epithelial cancer

Failed root canal treatment is best addressed primarily with the provision of repeat endodontic treatment with thorough irrigation under isolation. If a post is present in the root of the tooth it needs to be removed first. This paper is the second in a series of two which provide an overview of techniques for post removal. Specifically designed post removal devices and the removal of fibre posts are described. Post removal device techniques are illustrated with a series of clinical case figures

A wet process for oxidation-absorption of nitric oxide by persulfate/calcium peroxide

The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.cej.2018.05.145 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/This study develops and evaluates a novel wet method for NO removal using a Na2S2O8/CaO2 solution. The effects of these two components both and alone in solution, Na2S2O8 concentration, CaO2 concentration, initial pH, reaction temperature, and the concentrations of NO and O2 on NO removal efficiency were evaluated using a bubbling reactor. The combination of Na2S2O8 and CaO2 had a synergistic effect on NO removal efficiency. NO removal was effected by CaO2 concentration, reaction temperature and the initial solution pH, while Na2S2O8 concentration and O2 concentration had little effect. The NO removal efficiency decreased linearly from 94.5 % to 75.1 % when the NO concentration increased from 139 to 559 ppm. The products were characterized using XRD, XPS and IC, and CaSO4·2H2O, NO3− and SO42− were found to be the main products. The EPR analysis showed that free radicals of O2−, SO4− and OH were the key species involved in the NO removal process. Finally, the corresponding reaction mechanisms were proposed.International S&T Cooperation Program of China [Grant No. 2015DFG61910

Association of opioid receptor mu 1 (OPRM1) A118G polymorphism (rs1799971) with nicotine dependence

Background and Object Whether opioid-receptor mu 1 (OPRM1) A118G polymorphism (rs1799971) is associated with nicotine dependence is controversial. We analyzed the combined results from published studies of this possibility. Methods: Literature reviews were performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Web of Science, Chinese National Science Infrastructure (CNKI), PubMed, Embase and Google Scholar database searches using MeSH terms were conducted to find all relevant researches up to October 2016. Odds ratios (ORs) and their 95% confidence intervals (95% CIs) were calculated in allele, homozygote, heterozygote, dominant and recessive models. Ethnicity-specific subgroup meta-analysis, heterogeneity, sensitivity analysis and publication bias were considered. Results: Seven eligible studies with 3313 patients were included. The ORs in the five genetic models mentioned above were 1.000 (95% CI: 0.906, 1.104; p = 0.999), 1.032 (95% CI: 0.771, 1.381; p = 0.834), 0.963 (95% CI: 0.799, 1.162; p = 0.696), 1.006 (95% CI: 0.916, 1.104; p = 0.907), 0.967 (95% CI: 0.715, 1.309; p = 0.830), respectively. Only in dominant model is the association significant. Upon ethnicity-specific subgroup analysis, there is no statistical significance. Conclusion: OPRM1-A118G polymorphism (A>G) is not associated with nicotine dependence

Applications of functional near-infrared spectroscopy in non-drug therapy of traditional Chinese medicine: a review

Non-drug therapies of traditional Chinese medicine (TCM), including acupuncture, massage, tai chi chuan, and Baduanjin, have emerged as widespread interventions for the treatment of various diseases in clinical practice. In recent years, preliminary studies on the mechanisms of non-drug therapies of TCM have been mostly based on functional near-infrared spectroscopy (fNIRS) technology. FNIRS is an innovative, non-invasive tool to monitor hemodynamic changes in the cerebral cortex. Our review included clinical research conducted over the last 10 years, establishing fNIRS as a reliable and stable neuroimaging technique. This review explores new applications of this technology in the field of neuroscience. First, we summarize the working principles of fNIRS. We then present preventive research on the use of fNIRS in healthy individuals and therapeutic research on patients undergoing non-drug therapies of TCM. Finally, we emphasize the potential for encouraging future advancements in fNIRS studies to establish a theoretical framework for research in related fields

The asymmetric photosynthetic characteristics of the isobilateral sorghum leaves under the illumination of the diffuse light

The difference between photosynthesis on the two leaf sides (dorsoventral asymmetry) of photosynthesis is important for light-use patterns, but the asymmetry is environment dependent. Its role in photosynthetic regulation has been intensively studied, but little is known about the impacts of direct and diffuse light on the asymmetry. Because of the current changing fraction of diffuse light in sky radiation, this study investigated the dorsoventral asymmetry of photosynthetic traits under direct and diffuse light conditions in an important food and energy crop, Sorghum bicolor L. A unique method was used to investigate the specific gas exchange of each leaf surface. Anatomical and morphological traits were different between the two surfaces of sorghum leaves, which might result in photosynthetic asymmetry. The variations in photosynthetic rates and stomatal conductance were significant between the two surfaces in direct and diffuse light, but the degree of dorsoventral asymmetry decreased in diffuse light. The integrated PN and Gs of the adaxial illumination were significantly higher than that of abaxial illumination both in direct and diffuse light in sorghum leaves, but the ASI of the integrated PNwas 2.83 in direct light, while significantly dropped to 1.69 in diffuse light. Significant morphological differences between the two surfaces might cause photosynthetic asymmetry in the sorghum leaves. The variations of specific gas exchange were significant between direct and diffuse light, including in the incident and self-transmitted light. Compared with direct light, diffuse light reduced the stomatal sensitivity, with the degree of decline being greater in the adaxial surface, which caused weak dorsoventral asymmetry in photosynthesis. The specific photosynthetic characteristics in sorghum leaves varied obviously in direct and diffuse light, including in the incident and self-transmitted light, which contributed to the different overall gas exchange. Compared with direct light, the decline of stomatal sensitivity, which showed positive correlation with stomatal density, caused weakened dorsoventral asymmetry in photosynthesis in diffuse light. The findings provide new insights into dorsoventral asymmetry and the impact of diffuse light on photosynthesis in isobilateral leaves