We Know What You Choose! External Validity of Discrete Choice Models

For over the last thirty years the multinomial logit model has been the standard in choice modeling. Development in econometrics and computational algorithms has led to the increasing tendency to opt for more flexible models able to depict more realistically choice behavior. This study compares three discrete choice models, the standard multinomial logit, the error components logit, and the random parameters logit. Data were obtained from two choice experiments conducted to investigate consumers’ preferences for fresh pears receiving several postharvest treatments. Model comparisons consisted of in-sample and holdout sample evaluations. Results show that product characteristics hence, datasets, influence model performance. We also found that the multinomial logit model outperformed in at least one of three evaluations in both datasets. Overall, findings signal the need for further studies controlling for context and dataset to have more conclusive cues for discrete choice models capabilities.discrete choice models, validation, holdout sample

Effectiveness of Online Consumer Product Review: The Role of Experiential Information

Product reviews as consumer-generated information have drawn great attention from researchers and practitioners. A substantial academic effort has been made to comprehend factors influencing the helpfulness of reviews, largely centering on a few quantitative factors (e.g., star rating, review length). However, research investigating qualitative aspects of product reviews still lags, though product reviews consist mainly of peer consumers’ experiences and opinions. In this study, we use the smartphone reviews to investigate consumers’ experiences and opinions in relation to review helpfulness. By statistical analysis, we demonstrate that consumers’ experiential information plays a significant role to make product reviews helpful. We furnish additional evidence of the statistical results by predictive analytics. Our findings suggest that consumers’ experiential information conveys meaningful implication to better understand the nature of product reviews. Therefore, this study contributes to the extant literature of e-commerce and to practitioners to utilize the consumer reviews of their products

An Analysis of the Determinants of Beef Consumption and Consumer Preference Using BWS

This study sought to determine consumers’ beef value by utilizing the best-worst scaling method. Based on previous literatures related to consumers’ purchasing behavior and preferences for beef, a list of eleven beef values was compiled. Results show that on average the values of safety, freshness, origin, taste, and price were the most important to consumers, whereas the values of brand, size, purpose, marbling, and grade were the least important. However, there was significant heterogeneity in the relative importance placed on beef values. Results reveal that beef values are significantly related to consumers' stated and revealed preferences for beef

Prosocial Preference for the Consumption of Livestock Products

Substantial experimental and economic game research has attempted to explain people’s prosocial behavior. To test whether such social preferences exists in the field of purchasing livestock products, we estimated consumers’ preferences for environmental benefits, animal welfare concerns, and livestock farmers’ profits. We discovered that consumers are concerned about social benefits resulting from their purchase of livestock products. We also determined the extent to which people’s measured preferences for social benefits can explain consumers’ willingness to pay a premium for environmentally-friendly livestock products or those certified for animal welfare. Our results indicate: 1) social preferences explain a non-trivial portion of people’s willingness to pay a premium for livestock products mentioned above; and 2) the correlation between the estimated premium and people’s stated willingness to pay a premium is statistically significant and positive. Overall, our results suggest that concerns for social benefits can be observed in consumers’ behavior of purchasing livestock products

The Effect of Brand Equity across Seafood Products

The brand equity can be an important marketing strategy in seafood marketing industry. The effect of brand equity on unbreaded frozen products of shrimp, salmon and tilapia is measured through unit market share. The results indicate that brand equity of the selected seafood products scarcely exits. However, a noteworthy market share of store brands draws an important attention on a role of store brands in seafood markets

Identification of a novel circadian clock modulator controlling BMAL1 expression through a ROR/REV-ERB-response element-dependent mechanism

Circadian rhythms, biological oscillations with a period of about 24 h, are maintained by an innate genetically determined time-keeping system called the molecular circadian clockwork. Despite the physiological and clinical importance of the circadian clock, development of small molecule modulators targeting the core clock machinery has only recently been initiated. BMAL1, a core clock gene, is controlled by a ROR/REV-ERB-response element (RORE)-dependent mechanism, which plays an important role in stabilizing the period of the molecular circadian clock. Therefore, we aimed to identify a novel small molecule modulator that regulates Bmal1 gene expression in RORE-dependency, thereby influencing the molecular feedback loop of the circadian clock. For this purpose, we carried out a cell-based screen of more than 1000 drug-like compounds, using a luciferase reporter driven by the proximal region of the mouse Bmal1 promoter. One compound, designated KK-S6, repressed the RORE-dependent transcriptional activity of the mBmal1 promoter and reduced endogenous BMAL1 protein expression. More importantly, KK-S6 significantly altered the amplitude of circadian oscillations of Bmal1 and Per2 promoter activities in a dose-dependent manner, but barely affected the period length. KK-S6 effectively decreased mRNA expression of metabolic genes acting downstream of REV-ERBα, Pai-1 and Citrate synthase, that contain RORE cis-element in their promoter. KK-S6 likely acts in a RORE-dependent manner by reinforcing the REV-ERBα activity, though not by the same mechanism as known REV-ERB agonists. In conclusion, the present study demonstrates that KK-S6 functions as a novel modulator of the amplitude of molecular circadian rhythms by influencing RORE-mediated BMAL1 expression. © 2015 The Authors. Published by Elsevier Inc.

p190RhoGAP and Rap-dependent RhoGAP (ARAP3) inactivate RhoA in response to nerve growth factor leading to neurite outgrowth from PC12 cells

Rat pheochromocytoma (PC12) cells have been used to investigate neurite outgrowth. Nerve growth factor (NGF) has been well known to induce neurite outgrowth from PC12 cells. RhoA belongs to Ras-related small GTP-binding proteins, which regulate a variety of cellular processes, including cell morphology alteration, actin dynamics, and cell migration. NGF suppressed GTP-RhoA levels after 12 h in PC12 cells and was consistently required for a long time to induce neurite outgrowth. Constitutively active (CA)-RhoA suppressed neurite outgrowth from PC12 cells in response to NGF, whereas dominant-negative (DN)-RhoA stimulated it, suggesting that RhoA inactivation is essential for neurite outgrowth. Here, we investigated the mechanism of RhoA inactivation. DN-p190RhoGAP abrogated neurite outgrowth, whereas wild-type (WT)-p190RhoGAP and WT-Src synergistically stimulated it along with accelerating RhoA inactivation, suggesting that p190RhoGAP, which can be activated by Src, is a major component in inhibiting RhoA in response to NGF in PC12 cells. Contrary to RhoA, Rap1 was activated by NGF, and DN-Rap1 suppressed neurite outgrowth, suggesting that Rap1 is also essential for neurite outgrowth. RhoA was co-immunoprecipitated with Rap1, suggesting that Rap1 interacts with RhoA. Furthermore, a DN-Rap-dependent RhoGAP (ARAP3) prevented RhoA inactivation, abolishing neurite formation from PC12 cells in response to NGF. These results suggest that NGF activates Rap1, which, in turn, up-regulates ARAP3 leading to RhoA inactivation and neurite outgrowth from PC12 cells. Taken together, p190RhoGAP and ARAP3 seem to be two main factors inhibiting RhoA activity during neurite outgrowth in PC12 cells in response to NGF

Optimizing Surveillance Performance of Alpha-Fetoprotein by Selection of Proper Target Population in Chronic Hepatitis B

<div><p>Although alpha-fetoprotein (AFP) is the most widely used biomarker in hepatocellular carcinoma (HCC) surveillance, disease activity may also increase AFP levels in chronic hepatitis B (CHB). Since nucleos(t)ide analog (NA) therapy may reduce not only HBV viral loads and transaminase levels but also the falsely elevated AFP levels in CHB, we tried to determine whether exposure to NA therapy influences AFP performance and whether selective application can optimize the performance of AFP testing in CHB during HCC surveillance. A retrospective cohort of 6,453 CHB patients who received HCC surveillance was constructed from the electronic clinical data warehouse. Covariates of AFP elevation were determined from 53,137 AFP measurements, and covariate-specific receiver operating characteristics regression analysis revealed that albumin levels and exposure to NA therapy were independent determinants of AFP performance. C statistics were largest in patients with albumin levels ≥ 3.7 g/dL who were followed without NA therapy during study period, whereas AFP performance was poorest when tested in patients with NA therapy during study and albumin levels were < 3.7 g/dL (difference in C statics = 0.35, p < 0.0001). Contrary to expectation, CHB patients with current or recent exposure to NA therapy showed poorer performance of AFP during HCC surveillance. Combination of concomitant albumin levels and status of NA therapy can identify subgroup of CHB patients who will show optimized AFP performance.</p></div