Incentivizing Exploration with Selective Data Disclosure

We study the design of rating systems that incentivize (more) efficient social learning among self-interested agents. Agents arrive sequentially and are presented with a set of possible actions, each of which yields a positive reward with an unknown probability. A disclosure policy sends messages about the rewards of previously-chosen actions to arriving agents. These messages can alter agents' incentives towards exploration, taking potentially sub-optimal actions for the sake of learning more about their rewards. Prior work achieves much progress with disclosure policies that merely recommend an action to each user, but relies heavily on standard, yet very strong rationality assumptions. We study a particular class of disclosure policies that use messages, called unbiased subhistories, consisting of the actions and rewards from a subsequence of past agents. Each subsequence is chosen ahead of time, according to a predetermined partial order on the rounds. We posit a flexible model of frequentist agent response, which we argue is plausible for this class of "order-based" disclosure policies. We measure the success of a policy by its regret, i.e., the difference, over all rounds, between the expected reward of the best action and the reward induced by the policy. A disclosure policy that reveals full history in each round risks inducing herding behavior among the agents, and typically has regret linear in the time horizon $T$. Our main result is an order-based disclosure policy that obtains regret $\tilde{O}(\sqrt{T})$. This regret is known to be optimal in the worst case over reward distributions, even absent incentives. We also exhibit simpler order-based policies with higher, but still sublinear, regret. These policies can be interpreted as dividing a sublinear number of agents into constant-sized focus groups, whose histories are then revealed to future agents

Modeling Heterogeneity in Consumer Preferences for Select Food Safety Attributes in China

Food safety issues often arise from problems of asymmetric information between consumers and suppliers with regards to product-specific attributes. Severe food safety scandals were observed recently in China that not only caused direct economic and life loss but also created distrust in the Chinese food system domestically as well as internationally. While much attention has focused on the problems plaguing the Chinese government’s food inspection system, little research has been dedicated to analyze consumers’ concerns over food safety. In this paper we measure consumer preferences for select food safety attributes in pork and take their food safety risk perceptions into account. Several choice experiment models, including latent class and random parameters logit, are constructed to capture heterogeneity in consumer preferences. A statistical sample of 6,720 observations is obtained from a choice experiment administered in seven major Chinese metropolitan cities. Our results suggest that Chinese consumers have the highest willingness-to-pay for a government certification program, followed by a traceability system, third party certification and a product-specific information label. The results of this study call upon the direct involvement of the Chinese government in the food safety system. A more strict monitoring system will not only improve consumer welfare in the short-run but also restore consumers’ trust leading to a social welfare increase in the long run.Food safety, choice experiment, willingness-to-pay, risk perceptions, random parameters logit, latent class logit, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Q13, Q17, Q18,

STING-mediated disruption of calcium homeostasis chronically activates ER stress and primes T cell death

STING gain-of-function mutations cause lung disease and T cell cytopenia through unknown mechanisms. Here, we found that these mutants induce chronic activation of ER stress and unfolded protein response (UPR), leading to T cell death by apoptosis in th

Got (Safe) Milk? Chinese Consumers’ Valuation for Select Food Safety Attributes

Food safety issues often arise from problems of asymmetric information between consumers and suppliers of food with regards to product-specific attributes or characteristics. Food safety concerns in China are having a drastic impact on consumer behavior, commodity markets, international trade and food security. An additional challenge to the problem of asymmetric information lies in the inherent structure of the governing bodies which oversee food safety and quality. Unlike the United States and other developed countries, China’s food safety is regulated by several government entities with different and sometimes overlapping responsibilities. As a result consumers don’t have a comprehensive food safety and quality system on which to base their economic decisions. In an effort to maintain the food supply of the world’s largest economy safe, China’s government has approved a series of tougher food safety laws and regulations. Although publicized as a tough approach to food safety, it is unclear whether this latest effort will make China’s food safer to eat and improve the country’s image to its agricultural trading partners. While much attention has focused on the problems plaguing China’s food inspection system, little research has been dedicated to analyze consumers’ concerns over food safety. In this paper we measure consumer preferences for select food safety attributes in milk. More specifically we estimate consumer’s willingness to pay for government certification, an independent (third party) certification program, national brand, and a product’s shelf-life using a choice experiment approach. We compare and contrast several modeling strategies to capture heterogeneity of consumer preferences. The data used in this study was collected from a choice experiment administered in seven major metropolitan cities in China, yielding a statistical sample of 6,720 observations. Our results suggest that Chinese consumers have the highest willingness-to-pay for a government certification program, followed by national brand, private certification, and longer shelf-life products. We find that Chinese consumers are very concerned about the safety of the milk they purchase and are willing to pay a high premium to assure that their food is safe. The high level of concern regarding milk safety is linked to recent food safety incidents involving dairy products, most notably the Melamine-adulterated milk products. Heterogeneity of consumer preferences and willingness to pay for the select food safety attributes was found by implementing a latent class logit model based on attitudinal responses as well as a mixed logit model. Although it might appear that Chinese consumers’ confidence on the government is eroding, as reported in the wake of recent food safety scandals, our research found that consumers were less confident on non-government food safety control measures. This result indicates that there is a strong need for the Chinese government to provide adequate food safety and quality control. Our findings call upon the direct involvement of the Chinese government in the food safety system. A more strict monitoring system via certification is necessary. If realized, such government efforts will provide higher welfare to consumers in the short-run and will restore consumers’ trust increasing social welfare in the long run. Policy implications of our results are discussed with particular attention given to food safety and security issues.China, Choice experiment, Mixed logit, Latent class logit, Food safety, Preference heterogeneity, Willingness-to-pay, Food Consumption/Nutrition/Food Safety, International Relations/Trade, Marketing, Q11, Q18,

A one year audit of patients with venous thromboembolism presenting to a tertiary hospital in Johannesburg, South Africa

Abstract: Introduction: Given the growing burden of venous thromboembolism (VTE) worldwide and the paucity of data from the developing world, the aim of this study was to audit the characteristics, risk factors and length of hospital stay of patients with VTE presenting to a tertiary hospital emergency centre in Johannesburg, South Africa. Methods: The study was a retrospective record review of all patients who presented with VTE to a tertiary academic emergency centre in Johannesburg, South Africa from 1 April 2012 to 30 March 2013. Results: Venous thromboembolism was identified in 74 patients; 56 (75.7%) with isolated deep vein thrombosis, 13 (17.6%) with pulmonary embolism and five (6.8%) who had a concurrent deep vein thrombosis with pulmonary embolism. The median age of the patients was 40 years old (range 19–90). The female to male ratio was 2:1. HIV infection, tuberculosis and history of immobilisation were the most common risk factors. The median duration of hospital stay was 14 days (range 4–36). A therapeutic International Normalised Ratio at discharge was only reached in 36.5% of patients. Conclusion: Venous thromboembolism presentation to the emergency centre is not common, but the risks associated with the morbidity and mortality related to it makes it important despite its relative scarcity. The prevalence of HIV infection amongst patients with VTE is concerning – not only related to the frequency of the pathology but also due to HIV not being factored into the common VTE risk stratification scores

Synergistic up-regulation of CXCL10 by virus and IFN γ in human airway epithelial cells.

Airway epithelial cells are the first line of defense against viral infections and are instrumental in coordinating the inflammatory response. In this study, we demonstrate the synergistic stimulation of CXCL10 mRNA and protein, a key chemokine responsible for the early immune response to viral infection, following treatment of airway epithelial cells with IFN γ and influenza virus. The synergism also occurred when the cells were treated with IFN γ and a viral replication mimicker (dsRNA) both in vitro and in vivo. Despite the requirement of type I interferon (IFNAR) signaling in dsRNA-induced CXCL10, the synergism was independent of the IFNAR pathway since it wasn't affected by the addition of a neutralizing IFNAR antibody or the complete lack of IFNAR expression. Furthermore, the same synergistic effect was also observed when a CXCL10 promoter reporter was examined. Although the responsive promoter region contains both ISRE and NFκB sites, western blot analysis indicated that the combined treatment of IFN γ and dsRNA significantly augmented NFκB but not STAT1 activation as compared to the single treatment. Therefore, we conclude that IFN γ and dsRNA act in concert to potentiate CXCL10 expression in airway epithelial cells via an NFκB-dependent but IFNAR-STAT independent pathway and it is at least partly regulated at the transcriptional level