4,231 research outputs found

    Confounded by the Field: Bidding in Food Auctions When Field Prices Are Increasing

    Get PDF
    Auction experiments are commonly used to determine consumers’ willingness to pay for various food items. While their non-hypothetical nature is a positive, market substitutes create a probable confounding of bids by field prices. This study examines the influence of field prices on bids for four foods in two versions by conducting auctions before and after large price increases in 2007. Results show that bids were capped at given field prices and were significantly higher in sessions conducted after store prices increased. Percentage premiums, however, were not significantly different across sessions, suggesting that effects of field prices could be reduced. Overall, researchers must be conscious of how field prices affect bids.auction experiments, field prices, organic, bidding, Consumer/Household Economics, Institutional and Behavioral Economics, Marketing,

    Differences in WTP and Consumer Demand for Organic and Non-GM Fresh and Processed Foods

    Get PDF
    Auction experiments were used to examine demand and premium differences between organic, non-GM (genetically modified), and conventional versions for two pairs of fresh and processed foods. Results showed processed foods had greater substitutability among the versions than fresh products. Conventional versions were the least price sensitive, while non-GM versions were the most sensitive. Significant premium differences were found between fresh and processed foods for sweet corn and tortilla chips, but not for potatoes and potato chips. Results from random effects models mirrored these findings. In general, the extent of premium differences between fresh and processed versions appears dependent on the food product.auction experiments, willingness to pay, organic, non-GM, fresh, processed food, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Marketing,

    Intra-organizational integration and innovation: organizational structure, environmental contingency and R&D performance

    Get PDF
    It is widely thought that intra-firm integration has a positive effect on organizational performance, especially in environments characterized by complex and uncertain information. However, counter arguments suggest that integration may limit flexibility and thereby reduce performance in the face of uncertainty. Research and development activities of a firm are especially likely to face complex and uncertain information environments. Following prior work in contingency theory, this paper analyzes the effects of intra-organizational integration on manufacturing firms’ innovative performance. Based on a survey of R&D units in US manufacturing firms and patent data from the NBER patent database, we examine the relation between mechanisms for linking R&D to other units of the firm and the relative innovativeness of the firm. Furthermore, we argue that the impact of integration may vary by the importance of secrecy in protecting firms’ innovation advantages. We find that intra-firm integration is associated with higher self-reported innovativeness and more patents. We also find some evidence that this effect is moderated by the appropriability regime the firm faces, with the benefits of cross-functional integration being weaker in industries where secrecy is especially important. These results both support and develop the contingency model of organizational performance.Innovation; Organizations; Contingency theory;

    Astrocytic LRP1 mediates brain Aβ clearance and impacts amyloid deposition

    Get PDF
    Accumulation and deposition of amyloid-β (Aβ) in the brain represent an early and perhaps necessary step in the pathogenesis of Alzheimer's disease (AD). Aβ accumulation leads to the formation of Aβ aggregates, which may directly and indirectly lead to eventual neurodegeneration. While Aβ production is accelerated in many familial forms of early-onset AD, increasing evidence indicates that impaired clearance of Aβ is more evident in late-onset AD. To uncover the mechanisms underlying impaired Aβ clearance in AD, we examined the role of low-density lipoprotein receptor-related protein 1 (LRP1) in astrocytes. Although LRP1 has been shown to play critical roles in brain Aβ metabolism in neurons and vascular mural cells, its role in astrocytes, the most abundant cell type in the brain responsible for maintaining neuronal homeostasis, remains unclear. Here, we show that astrocytic LRP1 plays a critical role in brain Aβ clearance. LRP1 knockdown in primary astrocytes resulted in decreased cellular Aβ uptake and degradation. In addition, silencing of LRP1 in astrocytes led to downregulation of several major Aβ-degrading enzymes, including matrix metalloproteases MMP2, MMP9, and insulin-degrading enzyme. More important, conditional knock-out of theLrp1gene in astrocytes in the background of APP/PS1 mice impaired brain Aβ clearance, exacerbated Aβ accumulation, and accelerated amyloid plaque deposition without affecting its production. Together, our results demonstrate that astrocytic LRP1 plays an important role in Aβ metabolism and that restoring LRP1 expression and function in the brain could be an effective strategy to facilitate Aβ clearance and counter amyloid pathology in AD.SIGNIFICANCE STATEMENTAstrocytes represent a major cell type regulating brain homeostasis; however, their roles in brain clearance of amyloid-β (Aβ) and underlying mechanism are not clear. In this study, we used both cellular models and conditional knock-out mouse models to address the role of a critical Aβ receptor, the low-density lipoprotein receptor-related protein 1 (LRP1) in astrocytes. We found that LRP1 in astrocytes plays a critical role in brain Aβ clearance by modulating several Aβ-degrading enzymes and cellular degradation pathways. Our results establish a critical role of astrocytic LRP1 in brain Aβ clearance and shed light on specific Aβ clearance pathways that may help to establish new targets for AD prevention and therapy.</jats:p

    a comparative analysis of CDM in South Africa and China

    Get PDF
    Both South Africa and China are emergent economies heavily dependent on fossilfuel based energy sources, and the potential to leverage the Clean Development Mechanism (CDM) is significant in both countries. However, experience to date with CDM indicates South Africa has significantly lagged behind China in the uptake of the CDM, accounting for only 0.9% of the worldwide registered annual Certified Emission Reductions (CERs) while China has dominated the market, generating over 54% of the annual worldwide CERs. Thus, an opportunity exists to redefine the role of CDM in South Africa to better incentivise a lower carbon development trajectory. This paper provides a comparative analysis of the CDM experience in China and South Africa in order to identify the underlying drivers and obstacles to CDM in both countries. It is the authors’ objective to analyse the lessons learnt from marketleading China and laggard South Africa to better understand the structures and policies necessary within host CDM countries to unlock the potential of CDM in a post 2012 regime

    Invasion of the central nervous system by Cryptococcus neoformans requires a secreted fungal metalloprotease.

    Get PDF
    UnlabelledCryptococcus spp. cause life-threatening fungal infection of the central nervous system (CNS), predominantly in patients with a compromised immune system. Why Cryptococcus&nbsp;neoformans has this remarkable tropism for the CNS is not clear. Recent research on cerebral pathogenesis of C.&nbsp;neoformans revealed a predominantly transcellular migration of cryptococci across the brain endothelium; however, the identities of key fungal virulence factors that function specifically to invade the CNS remain unresolved. Here we found that a novel, secreted metalloprotease (Mpr1) that we identified in the extracellular proteome of C.&nbsp;neoformans (CnMpr1) is required for establishing fungal disease in the CNS. Mpr1 belongs to a poorly characterized M36 class of fungalysins that are expressed in only some fungal species. A strain of C.&nbsp;neoformans lacking the gene encoding Mpr1 (mpr1Δ) failed to breach the endothelium in an in vitro model of the human blood-brain barrier (BBB). A mammalian host infected with the mpr1Δ null strain demonstrated significant improvement in survival due to a reduced brain fungal burden and lacked the brain pathology commonly associated with cryptococcal disease. The in vivo studies further indicate that Mpr1 is not required for fungal dissemination and Mpr1 likely targets the brain endothelium specifically. Remarkably, the sole expression of CnMPR1 in Saccharomyces&nbsp;cerevisiae resulted in a robust migration of yeast cells across the brain endothelium, demonstrating Mpr1's specific activity in breaching the BBB and suggesting that Mpr1 may function independently of the hyaluronic acid-CD44 pathway. This distinct role for Mpr1 may develop into innovative treatment options and facilitate a brain-specific drug delivery platform.ImportanceCryptococcus neoformans is a medically relevant fungal pathogen causing significant morbidity and mortality, particularly in immunocompromised individuals. An intriguing feature is its strong neurotropism, and consequently the hallmark of cryptococcal disease is a brain infection, cryptococcal meningoencephalitis. For C.&nbsp;neoformans to penetrate the central nervous system (CNS), it first breaches the blood-brain barrier via a transcellular pathway; however, the identities of fungal factors required for this transmigration remain largely unknown. In an effort to identify extracellular fungal proteins that could mediate interactions with the brain endothelium, we undertook a proteomic analysis of the extracellular proteome and identified a secreted metalloprotease (Mpr1) belonging to the M36 class of fungalysins. Here we found that Mpr1 promotes migration of C.&nbsp;neoformans across the brain endothelium and into the CNS by facilitating attachment of cryptococci to the endothelium surface, thus underscoring the critical role of M36 proteases in fungal pathogenesis

    Detecting Interlocutor Confusion in Situated Human-Avatar Dialogue: A Pilot Study

    Get PDF
    In order to enhance levels of engagement with conversational systems, our long term research goal seeks to monitor the confusion state of a user and adapt dialogue policies in response to such user confusion states. To this end, in this paper, we present our initial research centred on a user-avatar dialogue scenario that we have developed to study the manifestation of confusion and in the long term its mitigation. We present a new definition of confusion that is particularly tailored to the requirements of intelligent conversational system development for task-oriented dialogue. We also present the details of our Wizard-of-Oz based data collection scenario wherein users interacted with a conversational avatar and were presented with stimuli that were in some cases designed to invoke a confused state in the user. Post study analysis of this data is also presented. Here, three pre-trained deep learning models were deployed to estimate base emotion, head pose and eye gaze. Despite a small pilot study group, our analysis demonstrates a significant relationship between these indicators and confusion states. We see this as a useful step forward in the automated analysis of the pragmatics of dialogue
    corecore