891 research outputs found

    The Measurement And Effect Of Dissolved Oxygen On Candida Lipolytica

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    Cross-classification analysis in the field of management and organization : comments on the DEL-technique

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    The DEL-technique, a proportionate reduction in error measure, developed by Hildebrand, Laing and Rosenthal, has been applied and portrayed as a promising prediction analysis technique to evaluate theory on the basis of cross-classification data, though it was controversial at its birth in the early 70s. According to the opponents, Goodman and Kruskal, the interpretation of DEL as a proportionate reduction in error measure of knowing a prediction rule over not knowing the prediction rule, cannot be held, because it is benchmarked against independence instead of ignorance. However, even when neglecting this criticism the DEL-measure can be easily misinterpreted as a measure of acceptance of the specified customized hypothesis as the only and best relationship between two categorical variables, when the context for the interpretation is not carefully stated in terms of the adhered research paradigm: theory-testing versus prediction logic. When taking into account this criticism, the researchers need to be acknowledged for clearly addressing some of the methodological problems in prediction research, however, an alternative proportionate reduction in error measure may generate unequivocally interpretable results and outperforms the DEL-technique.

    Market-oriented product development as an organizational learning capability: findings from two cases

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    Conceptualizing market orientation at the level of the product development process is relevant, because market orientation is a highly critical factor for new product success and this conceptualization can be used as a starting-point to transform the whole organization into a more market oriented one. Market-oriented product development appears to be more than carrying out a number of marketing activities in a product development process. Using concepts from resourcebased theory and organizational learning theory, we draw up a conceptual framework of marketoriented product development as an organizational learning capability substantiated by findings from two case studies. This capability encapsulates the values and norms, knowledge and skills, technical and managerial knowledge systems, which enable learning about markets through information processing behavior in product development and improve this market learning behavior. This conceptualization stimulates research on operationalizing market orientation in the managerial context of a critical business process and research on enhancing the degree of market orientation.

    An All Linear Optical Quantum Memory Based on Quantum Error Correction

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    When photons are sent through a fiber as part of a quantum communication protocol, the error that is most difficult to correct is photon loss. Here, we propose and analyze a two-to-four qubit encoding scheme, which can recover the loss of one qubit in the transmission. This device acts as a repeater when it is placed in series to cover a distance larger than the attenuation length of the fiber, and it acts as an optical quantum memory when it is inserted in a fiber loop. We call this dual-purpose device a ``quantum transponder.''Comment: 4 pages, 5 figure

    Evaluating traffic informers: Testing the behavioral and social-cognitive effects of an adolescent bicycle safety education program

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    AbstractIn The Netherlands, 12–24 years old are over-represented in the total number of traffic fatalities and injuries. In this study, the traffic informer program – designed to promote safe traffic behavior in the pre-driver population – was experimentally evaluated, with a specific focus on bicycle use. Students were subjected to graphic videos of traffic accidents and listened to a first-person narrative provided by a traffic accident victim. The influence of the program on concepts derived from the theory of planned behavior and protection motivation theory (attitudes, norms, self-efficacy, risk-perception, intention and behavior) was assessed. Students from various schools (N=1593;M age=15 years, SD=.84) participated in a quasi-experimental study, either in an experimental or a control group, completing self-report questionnaires one week prior to the program implementation and approximately one month after the program implementation. Mixed regression analyses showed significant positive and negative time×intervention interaction effects on attitude toward traffic violations, relative attitude toward traffic safety, and risk comparison, but not on intention and behavior. More research is needed to find effective behavioral change techniques (other than increasing risk awareness) for promoting safe traffic behavior in adolescents. Research is also needed to address how these can be translated into effective interventions and educational programs

    Role of Bifidobacterium pseudocatenulatum in Degradation and Consumption of Xylan-Derived Carbohydrates

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    Xylans, a family of xylose-based polysaccharides, are dietary fibers resistant to digestion. They therefore reach the large intestine intact; there, they are utilized by members of the gut microbiota. They are initially broken down by primary degraders that utilize extracellular xylanases to cleave xylan into smaller oligomers. The resulting xylooligosaccharides (XOS) can either be further metabolized directly by primary degraders or cross-feed secondary consumers, including Bifidobacterium. While several Bifidobacterium species have metabolic systems for XOS, most grow poorly on longer- chain XOS and xylan substrates. In this study, we isolated strains of Bifidobacterium pseudocatenulatum and observed that some, including B. pseudocatenulatum ED02, displayed growth on XOS with a high degree of polymerization (DP) and straight-chain xylan, suggesting a primary degrader phenotype that is rare in Bifidobacterium. In silico analyses revealed that only the genomes of these xylan-fermenting (xylan+) strains contained an extracellular GH10 endo-β-1.4 xylanase, a key enzyme for primary degradation of xylan. The presence of an extracellular xylanase was confirmed by the appearance of xylan hydrolysis products in cell-free supernatants. Extracellular xylanolytic activity was only detected in xylan+ strains, as indicated by the production of XOS fragments with a DP of 2 to 6, identified by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Additionally, in vitro fecal fermentations revealed that strains with a xylan+ phenotype can persist with xylan supplementation. These results indicate that xylan+ B. pseudocatenulatum strains may have a competitive advantage in the complex environment of the gastrointestinal tract, due to their ability to act as primary degraders of xylan through extracellular enzymatic degradation

    Predicting Personalized Responses to Dietary Fiber Interventions: Opportunities for Modulation of the Gut Microbiome to Improve Health

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    Inadequate dietary fiber consumption has become common across industrialized nations, accompanied by changes in gut microbial composition and a dramatic increase in chronic metabolic diseases.The human gut microbiome harbors genes that are required for the digestion of fiber, resulting in the production of end products that mediate gastrointestinal and systemic benefits to the host. Thus, the use of fiber interventions has attracted increasing interest as a strategy to modulate the gut microbiome and improve human health. However, considerable interindividual differences in gut microbial composition have resulted in variable responses toward fiber interventions. This variability has led to observed nonresponder individuals and highlights the need for personalized approaches to effectively redirect the gut ecosystem. In this review, we summarize strategies used to address the responder and nonresponder phenomenon in dietary fiber interventions and propose a targeted approach to identify predictive features based on knowledge of fiber metabolism and machine learning approaches

    The Future of Synbiotics: Rational Formulation and Design

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    Synbiotics, mixtures of live microbes and substrates selectively utilized by host organisms, are of considerable interest due to their ability to improve gastrointestinal health. However, formulating synbiotics remains challenging, due in part, to the absence of rational strategies to assess these products for synbiotic activities prior to clinical trials. Currently, synbiotics are formulated as either complementary or synergistic. Complementary synbiotics are made by combining probiotics and prebiotics, with each component acting independently and with the combination shown to provide a clinical health benefit. Most commercial synbiotics as well as those used in clinical trials have been of the complementary type. In contrast, synergistic synbiotics require that the added microbe is specifically stimulated or it’s persistence or activity are enhanced by the cognate substrate. Although several innovative examples have been described in the past few years based on this principle, in practice, relatively few synbiotic studies have tested for synergism. In this review, selected recent examples of complementary and synergistic synbiotics and the rationale for their formulation will be described. In addition, pre-clinical experimental approaches for identifying combinations that provide a basis for satisfying the requirements for synergism will be discussed
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