393 research outputs found

    The Impact of Interface Quality on Trust in Web Retailers

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    Web retailing is expected to grow at aggressive rates in future years. One of the most important factors that is slowing down this growth is the lack of trust of potential customers. So, as transactions through the internet develop and mature, success will largely be dependent on gaining and0501ntaining this trust. It has been suggested that the quality of the user interface of the Web site is a determinant of the initial establishment of trust. In this article, we describe a study where 66 subjects were asked to perform some predefined book purchasing task in a series of sites with varying interface quality. We found a strong relationship between interface quality and trust. We also found some components of user interface quality to be more important than others and discuss the implications for Web site design. Le manque de confiance constitue une des barrières les plus importantes à l'adoption et au développement du commerce électronique. Centré sur le commerce électronique de détail, ce travail présente un modèle permettant d'analyser le développement de la confiance du consommateur en fonction des caractéristiques de ce dernier - sa propension - et de la perception qu'il a de certaines caractéristiques du commerçant, soit l'intégrité, l'habilité et la bienveillance de ce dernier. L'utilisabilité de l'interface graphique a été retenue comme étant le facteur-clé en ce qui concerne la perception de ces caractéristiques. Le rôle de chacune des dimensions composant l'utilisabilité a donc été étudié et mis en évidence relativement à la confiance développée par le consommateur.User interface, laboratory experiment, trust, usability, electronic retailing, web design, Interface utilisateur, expérimentation en laboratoire, confiance, b2c, commerce électronique (détail), design de site web

    Techno-Economic Modeling of a Corn Based Ethanol Plant in 2011

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    As studies continue to examine new value added uses for ethanol coproducts, it is important to have means to easily determine the feasibility of the processing steps involved. Many industries widely use computer simulation programs for this purpose, and for planning the use of resources and equipment capacities, and to determine processing costs. The objective of this project was to determine the sensitivity of 40 million gal/y corn-based ethanol plant model to changes in input material prices, product market prices, and various coproduct processing scenarios (i.e., oil extraction and drying of DDGS). The techno-economics of the base case ethanol plant were examined by factorially adjusting material and market costs, as well as adjusting the quantities of distillers wet grains (DWG), distillers dried grains with solubles (DDGS), and corn oil produced. The simulations verified that corn price has the greatest impact on the overall annual operating costs for the ethanol plant, and that the market price of ethanol has the greatest impact on annual revenues. The effect of coproduct processing on utility usage was also observed; oil extraction and drying of DDGS consumed substantially more energy and had higher capital costs than production of DWG alone. It was apparent that coproducts are an essential component to the sustainability of an ethanol plant in that: 1) they have continued marketability to the livestock industry, and 2) processing is not overly-expensive. This study has provided a basis for further exploration of the feasibility of new coproduct processing options, and illustrates the use of the model for determination of processing costs and revenues, as well as mass and energy balances

    Metabolic processes sustaining the reviviscence of lichen Xanthoria elegans (Link) in high mountain environments.

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    International audienceTo survive in high mountain environments lichens must adapt themselves to alternating periods of desiccation and hydration. Respiration and photosynthesis of the foliaceous lichen, Xanthoria elegans, in the dehydrated state were below the threshold of CO2-detection by infrared gas analysis. Following hydration, respiration totally recovered within seconds and photosynthesis within minutes. In order to identify metabolic processes that may contribute to the quick and efficient reactivation of lichen physiological processes, we analysed the metabolite profile of lichen thalli step by step during hydration/dehydration cycles, using 31P- and 13C-NMR. It appeared that the recovery of respiration was prepared during dehydration by the accumulation of a reserve of gluconate 6-P (glcn-6-P) and by the preservation of nucleotide pools, whereas glycolytic and photosynthetic intermediates like glucose 6-P and ribulose 1,5-diphosphate were absent. The large pools of polyols present in both X. elegans photo- and mycobiont are likely to contribute to the protection of cell constituents like nucleotides, proteins, and membrane lipids, and to preserve the integrity of intracellular structures during desiccation. Our data indicate that glcn-6-P accumulated due to activation of the oxidative pentose phosphate pathway, in response to a need for reducing power (NADPH) during the dehydration-triggered down-regulation of cell metabolism. On the contrary, glcn-6-P was metabolised immediately after hydration, supplying respiration with substrates during the replenishment of pools of glycolytic and photosynthetic intermediates. Finally, the high net photosynthetic activity of wet X. elegans thalli at low temperature may help this alpine lichen to take advantage of brief hydration opportunities such as ice melting, thus favouring its growth in harsh high mountain climates

    Characterization of the microbiome associated with in situ earthen materials

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    Background The current increase in public awareness of environmental risks is giving rise to a growth of interest in the microbiological safety of buildings. In particular, microbial proliferation on construction materials can be responsible for the degradation of indoor air quality that can increase health-risk to occupants. Raw earth materials are still widely used throughout the world and, in some cases, are linked to heritage habitats, as in the southwest of France. Moreover, these building materials are currently the subject of renewed interest for ecological and economic reasons. However, the microbial status of earthen materials raises major concerns: could the microbiome associated with such natural materials cause disease in building occupants? Very few analyses have been performed on the microbial communities present on these supports. Characterizing the raw earth material microbiome is also important for a better evaluation and understanding of the susceptibility of such materials to microbial development. This study presents the distribution of in situ bacterial and fungal communities on different raw earth materials used in construction. Various buildings were sampled in France and the microbial communities present were characterized by amplicon high-throughput sequencing (bacterial 16S rRNA gene and fungal ITS1 region). Bacterial culture isolates were identified at the species level by MALDI-TOF mass spectrometry. Results The major fungal and bacterial genera identified were mainly associated with conventional outdoor and indoor environmental communities, and no specific harmful bacterial species were detected on earthen materials. However, contrary to expectations, few human-associated genera were detected in dwellings. We found lower microbial alpha-diversity in earthen material than is usually found in soil, suggesting a loss of diversity during the use of these materials in buildings. Interestingly enough, the main features influencing microbial communities were building history and room use, rather than material composition. Conclusions These results constitute a first in-depth analysis of microbial communities present on earthen materials in situ and may be considered as a first referential to investigate microbial communities on such materials according to environmental conditions and their potential health impact. The bacterial and fungal flora detected were similar to those found in conventional habitats and are thought to be mainly impacted by specific events in the building’s life, such as water damage

    Acute effects of pharmacological modifications of fatty acid metabolism on human satiety

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    The role of NEFA in eating behaviour is still poorly known. Our objective was to examine whether etomoxir (ETO), an inhibitor of NEFA oxidation, or (−)-hydroxycitrate (HCA), an inhibitor of lipogenesis which may indirectly stimulate NEFA oxidation, alters satiety. Post-lunch satiety was measured in eight normal-weight male subjects who were deprived of time cues and received on three occasions either ETO (320mg), HCA (2g) or placebo (PLA) in random order. Between lunch and dinner, blood was withdrawn continuously and collected every 10min for measures of plasma concentrations of glucose, insulin, lactate, TAG, NEFA, β-hydroxybutyrate (BHB), leptin and ghrelin. Results showed that HCA began to decrease hunger and desire to eat compared to PLA and ETO 210min after lunch and increased satiety duration compared to PLA by 70 (se 23) min (P<0·05), but did not modify energy intake at dinner. ETO did not affect any variable of satiety. HCA increased NEFA concentrations during the pre-dinner period, whereas ETO increased and decreased plasma concentrations of NEFA and BHB, respectively. Mean differences in plasma NEFA concentrations between HCA and PLA were predictive of the differences in satiety duration between treatments (r2 0·71, P<0·01). Among treatments, plasma leptin concentration at dinner onset was the only blood variable correlated with energy intake at this meal (r −0·75, P<0·0005). In healthy, normal-weight men, acute HCA increased the intensity and duration of satiety possibly via increased NEFA disposal for oxidatio

    Feasibility and Acceptability of an INtervention TO Increase MOBility in Older Hospitalized Medical Patients (INTOMOB): A Mixed-Methods Pilot Study.

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    Background: To reduce adverse outcomes of low hospital mobility, we need interventions that are scalable in everyday practice. This study assessed the feasibility and acceptability of the INTOMOB multilevel intervention addressing barriers to hospital mobility without requiring unavailable resources. Methods: The INTOMOB intervention, targeting older patients, healthcare professionals (HCPs) and the hospital environment, was implemented on acute general internal medicine wards of three hospitals (12/2022-03/2023). Feasibility and acceptability of the intervention were assessed and two types of accelerometers compared in a mixed methods study (patient and HCP surveys and interviews). Quantitative data were analyzed descriptively and qualitative data using a deductive approach. Results were integrated through meta-inferences. Results: Of 20 patients (mean age 74.1 years), 90% found the intervention helpful and 82% said the environment intervention (posters) stimulated mobility. The majority of 44 HCPs described the intervention as clear and helpful. There was no major implementation or technical issue. About 60% of patients and HCPs preferred a wrist-worn over an ankle-worn accelerometer. Conclusions: The INTOMOB intervention is feasible and well accepted. Patients' and HCPs' feedback allowed to further improve the intervention that will be tested in a cluster randomized trial and provides useful information for future mobility-fostering interventions

    Food allergy enhances allergic asthma in mice

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    BackgroundAtopic march refers to the typical transition from a food allergy in early childhood to allergic asthma in older children and adults. However the precise interplay of events involving gut, skin and pulmonary inflammation in this process is not completely understood.ObjectivesTo develop a mouse model of mixed food and respiratory allergy mimicking the atopic march and better understand the impact of food allergies on asthma.MethodsFood allergy to ovalbumin (OVA) was induced through intra-peritoneal sensitization and intra-gastric challenge, and/or a respiratory allergy to house dust mite (HDM) was obtained through percutaneous sensitization and intra-nasal challenges with dermatophagoides farinae (Der f) extract. Digestive, respiratory and systemic parameters were analyzed.ResultsOVA-mediated gut allergy was associated with an increase in jejunum permeability, and a worsening of Der f-induced asthma with stronger airway hyperresponsiveness and pulmonary cell infiltration, notably eosinophils. There was overproduction of the pro-eosinophil chemokine RANTES in broncho-alveolar lavages associated with an enhanced Th2 cytokine secretion and increased total and Der f-specific IgE when the two allergies were present. Both AHR and lung inflammation increased after a second pulmonary challenge.ConclusionGut sensitization to OVA amplifies Der f-induced asthma in mice
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