783 research outputs found

    THE CONFLUENCE OF I.4.0 TECHNOLOGIES AND NEW BUSINESS MODELS: A SYSTEMATIC LITERATURE REVIEW

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    Objective of the study: The study's objective is to provide a systematic literature review on the coevolution of the Technologies associated to Industry 4.0 and business models. Methodology/approach: The research was built on conceptual blocs at the interface between Industry 4.0 (I 4.0), business models (BM) and digitalization /digital business models (DBM) in order to identify relevant trends. Through bibliometric techniques, 80 articles were selected from Scopus and WoS, using specialized software. Originality/ Relevance: Few studies exist on the interface under analysis. This article contributes to this emerging literature, providing a synthesis of such literature, including both a detailed descriptive component and an analysis of the main thematic clusters associated to this interface. Main results: The literature still needs to evolve into a framework of a 4.0 business model. The majority of the existing studies focus on business models to specific technologies associated to Industry 4.0. Among the 80 articles scrutinized, 56 were associated to business models and I4.0, and 24 linked business models and digitalization. Few really described a business model that could be characterized as an I4.0 business model. Theoretical/methodological contributions: Identification of key studies underlying the elaboration of an innovative business model associated to I4.0. An immediate and useful characterization of the literature. Identification of the main thematic clusters. Social/management contributions: To provide academics and professionals (especially in Business/Economics) with a detailed and thorough review of the most relevant literature, including the main aspects underlying the creation of innovative business models based on I4.0

    Variable order Mittag-Leffler fractional operators on isolated time scales and application to the calculus of variations

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    We introduce new fractional operators of variable order on isolated time scales with Mittag-Leffler kernels. This allows a general formulation of a class of fractional variational problems involving variable-order difference operators. Main results give fractional integration by parts formulas and necessary optimality conditions of Euler-Lagrange type.Comment: This is a preprint of a paper whose final and definite form is with Springe

    Standardization of Preclinical PET/CT Imaging to Improve Quantitative Accuracy, Precision, and Reproducibility: A Multicenter Study

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    Preclinical PET/CT is a well-established noninvasive imaging tool for studying disease development/progression and the development of novel radiotracers and pharmaceuticals for clinical applications. Despite this pivotal role, standardization of preclinical PET/CT protocols, including CT absorbed dose guidelines, is essentially nonexistent. This study (1) quantitatively assesses the variability of current preclinical PET/CT acquisition and reconstruction protocols routinely used across multiple centers and scanners; and (2) proposes acquisition and reconstruction PET/CT protocols for standardization of multicenter data, optimized for routine scanning in the preclinical PET/CT laboratory. Methods: Five different commercial preclinical PET/CT scanners in Europe and the United States were enrolled. Seven different PET/CT phantoms were used for evaluating biases on default/general scanner protocols, followed by developing standardized protocols. PET, CT, and absorbed dose biases were assessed. Results: Site default CT protocols were the following: greatest extracted Hounsfield units (HU) were 133 HU for water and −967 HU for air; significant differences in all tissue equivalent material (TEM) groups were measured. The average CT absorbed doses for mouse and rat were 72 mGy and 40 mGy, respectively. Standardized CT protocol were the following: greatest extracted HU were −77 HU for water and −990 HU for air; TEM precision improved with a reduction in variability for each tissue group. The average CT absorbed dose for mouse and rat decreased to 37 mGy and 24 mGy, respectively. Site default PET protocols were the following: uniformity was substandard in one scanner, recovery coefficients (RCs) were either over- or underestimated (maximum of 43%), standard uptake values (SUVs) were biased by a maximum of 44%. Standardized PET protocols were the following: scanner with substandard uniformity improved by 36%, RC variability decreased by 13% points, and SUV accuracy improved to 10%. Conclusion: Data revealed important quantitative biases in preclinical PET/CT and absorbed doses with default protocols. Standardized protocols showed improvements in measured PET/CT accuracy and precision with reduced CT absorbed dose across sites. Adhering to standardized protocols generates reproducible and consistent preclinical imaging datasets, thus augmenting translation of research findings to the clinic

    The sulfur pathway and diagnosis of sulfate depletion in grapevine

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    Sulfur is an essential nutrient to all plant species. Plants assimilate sulfur in a well-described pathway, which has been taken up by roots. Regulatory mech- anism has been the subject of many research papers. However, recent studies highlighted differences between crop plants and the model plant Arabidopsis thaliana. Our work focuses on the identification of genes involved in the sulfur metabolism in the Vitis vinifera genome, and their response to sulfur deficiency and other abiotic stress endured by grapevine in the field, namely water stress. Here, we describe the identification and brief characterization of the first assimilation enzymes involved in the sulfur pathway, the enzyme responsible for sulfur activa- tion, ATP sulfurylase (ATPS), and the two enzymes that reduce sulfate to sulfide, Adenosine 50-phosphosulate reductase (APR) and Sulfite reductase (SiR). A reduc- tion was observed in the number of ATPS and APR isoforms identified in V. vinifera genome when compared to A. thaliana or Glycine max genomes. Two ATPS isoforms were present in the Vitis genome, of which only ATPS1 transcript was detected in the tested tissues, and one APR isoform, suggesting an absence of redundancy in the role of both enzymes. ATPS1, APR and SiR transcript level was up-regulated in response to 2 days exposure to sulfur deficiency in V. vinifera cell cultures, which was completely reversed by the addition of GSH to the culture medium. Apparently, oxidative stress triggered GSH has a pivotal role in the regulation of ATPS1, APR and SiR transcription level, since their up-regulation was observed in mRNA from field grapevine berries under water stress, which is known to induce oxidative stress.info:eu-repo/semantics/publishedVersio

    Effects of external nutrient sources and extreme weather events on the nutrient budget of a Southern European coastal lagoon

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    The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets.Portuguese Science and Technology Foundation (FCT) [POCI/MAR/58427/2004, PPCDT/MAR/58427/2004]; Portuguese Science and Technology Foundation (FCT

    An initial psychometric evaluation and exploratory cross-sectional study of the Body Checking Questionnaire among Brazilian women

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    Body checking is considered an expression of an excessive preoccupation with appearance. The first aim of this study was to evaluate the psychometric properties of a Brazilian Portuguese version of the Body Checking Questionnaire (BCQ). Additionally, we wanted to examine the questionnaire’s associations with body avoidance behaviour, body mass index, dietary habits, and the intensity, frequency, and length of physical exercise. Finally, we also examined the differences between the total BCQ score and the individual BCQ factor scores. Differences between active and sedentary persons and between non-dieters and those on weight-loss diets were also analyzed. For the psychometric study, 546 female public university students from four different courses were surveyed. Two minor samples of university students and eating disorders women were also recruited. In the second part of the study, 403 women were recruited from weight-loss programs, gyms, and a university. All participants were verbally invited to participate in the research and voluntarily took part. Confirmatory factor analysis showed a good fit to the original model of the Brazilian BCQ that retained all 23 items. Satisfactory evidence of construct validity and internal consistency were also generated through analysis of factor loadings, t-values, Cronbach’s alpha, and construct reliability tests. The results also showed associations among body checking and body avoidance, body satisfaction, social anxiety, body mass index, and the frequency and intensity of physical exercise. Significant differences were found between non-dieters and weight-loss dieters for all BCQ factors and the total BCQ score. For physically active and sedentary persons, a significant difference was only observed for idiosyncratic checking behaviour. In conclusion, the BCQ appears to be a valid and reliable scale for Brazilian research, and the associations and differences found in this study suggest that women at gyms and especially in weight-loss programs should be targeted for future body checking studies
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