814 research outputs found

    Using hierarchical information-theoretic criteria to optimize subsampling of extensive datasets

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    This paper addresses the challenge of subsampling large datasets, aiming to generate a smaller dataset that retains a significant portion of the original information. To achieve this objective, we present a subsampling algorithm that integrates hierarchical data partitioning with a specialized tool tailored to identify the most informative observations within a dataset for a specified underlying linear model, not necessarily first-order, relating responses and inputs. The hierarchical data partitioning procedure systematically and incrementally aggregates information from smaller-sized samples into new samples. Simultaneously, our selection tool employs Semidefinite Programming for numerical optimization to maximize the information content of the chosen observations. We validate the effectiveness of our algorithm through extensive testing, using both benchmark and real-world datasets. The real-world dataset is related to the physicochemical characterization of white variants of Portuguese Vinho Verde. Our results are highly promising, demonstrating the algorithm's capability to efficiently identify and select the most informative observations while keeping computational requirements at a manageable level

    A model-based framework assisting the design of vapor-liquid equilibrium experimental plans

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    In this paper we propose a framework for Model-based Sequential Optimal Design of Experiments to assist experimenters involved in Vapor-Liquid equilibrium characterization studies to systematically construct thermodynamically consistent models. The approach uses an initial continuous optimal design obtained via semidefinite programming, and then iterates between two stages (i) model fitting using the information available; and (ii) identification of the next experiment, so that the information content in data is maximized. The procedure stops when the number of experiments reaches the maximum for the experimental program or the dissimilarity between the parameter estimates during two consecutive iterations is below a given threshold. This methodology is exemplified with the D-optimal design of isobaric experiments, for characterizing binary mixtures using the NRTL and UNIQUAC thermodynamic models for liquid phase. Significant reductions of the confidence regions for the parameters are achieved compared with experimental plans where the observations are uniformly distributed over the domain

    Use of European pulses to produce functional beverages – From chickpea and lupin as dairy alternatives

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    Consumption of plant based products as dairy alternatives is increasing steeply. This diet transition can only be achieved if these products keep the nutritional value and meet consumer’s sensory acceptance. This work aimed to evaluate the decrease of the “beany” flavour and of raffinose, stachyose and verbascose contents in EU pulse beveragés production, and also the best lactic fermentation conditions of the beverages, towards chickpea- and lupin-based yoghurts, with rheology properties similar to the commercial soy yoghurts. The reduction of “beany” volatile compounds of chickpea and lupin beverages during processing was confirmed through GC–MS analysis. Soaking and cooking processes were effective in removing flatulence sugars with almost 48% loss from the initial content in lupin beverage. The fermentation conditions at 40 ◦C, 12 h and 2% (w/v) of starter concentration evidenced the best viscoelastic structure and flow properties. The lupin yoghurt-type showed a similar gel structure to commercial soy yoghurt.info:eu-repo/semantics/publishedVersio

    Relationship between postharvest diseases resistance and mineral composition of citrus fruit

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    reen and blue moulds, due to the pathogenic action of Penicillium digitatum and Penicillium italicum respectively are the main cause of orange losses during postharvest. Under Mediterranean climate conditions, both together are responsible for 80% of total postharvest citrus fruit decay. The type of orchard production system, field location with different types of climate and soil has a main influence on mineral composition of fruits. The mineral composition of fruits can have a significant impact on fruit quality and shelf life during postharvest period. These include effects on fruit colour, texture, disease susceptibility, juice composition and development of physiological disorders. Oranges from different regions from South of Spain and Portugal and from three different production systems (conventional, integrated and organic) were studied to evaluate whether both factors (origin and production system) affected the degree of fruit sensitivity to decay. Results indicate that the sensitivity to green or blue mould is determined better by the origin of fruit than by the system of production.info:eu-repo/semantics/publishedVersio

    Transverse depinning in strongly driven vortex lattices with disorder

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    Using numerical simulations we investigate the transverse depinning of moving vortex lattices interacting with random disorder. We observe a finite transverse depinning barrier for vortex lattices that are driven with high longitudinal drives, when the vortex lattice is defect free and moving in correlated 1D channels. The transverse barrier is reduced as the longitudinal drive is decreased and defects appear in the vortex lattice, and the barrier disappears in the plastic flow regime. At the transverse depinning transition, the vortex lattice moves in a staircase pattern with a clear transverse narrow-band voltage noise signature.Comment: 4 pages, 4 figure

    Whole-system metabolism and CO<sub>2</sub> fluxes in a Mediterranean Bay dominated by seagrass beds (Palma Bay, NW Mediterranean)

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    The relationship between whole-system metabolism estimates based on planktonic and benthic incubations (bare sediments and seagrass, Posidonia oceanica meadows), and CO2 fluxes across the air-sea interface were examined in the Bay of Palma (Mallorca, Spain) during two cruises in March and June 2002. Moreover, planktonic and benthic incubations were performed at monthly intervals from March 2001 to October 2002 in a seagrass vegetated area of the bay. From the annual study, results showed a contrast between the planktonic compartment, which was heterotrophic during most of the year, except for occasional bloom episodes, and the benthic compartment, which was slightly autotrophic. Whereas the seagrass community was autotrophic, the excess organic carbon production therein could only balance the excess respiration of the planktonic compartment in shallow waters (<10 m) relative to the maximum depth of the bay (55 m). This generated a horizontal gradient from autotrophic or balanced communities in the shallow, seagrass-covered areas of the bay, to strongly heterotrophic communities in deeper areas, consistent with the patterns of CO2 fields and fluxes across the bay observed during the two extensive cruises in 2002. Finally, dissolved inorganic carbon and oxygen budgets provided NEP estimates in fair agreement with those derived from direct metabolic estimates based on incubated samples over the Posidonia oceanica meadow

    Drug Utilisation Patterns of Alternatives to Ranitidine-Containing Medicines in Patients Treated with Ranitidine:A Network Analysis of Data from Six European National Databases

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    Introduction: Ranitidine, a histamine H2-receptor antagonist (H2RA), is indicated in the management of gastric acid-related disorders. In 2020, the European Medicines Agency (EMA) recommended suspension of all ranitidine-containing medicines in the European Union (EU) due to the presence of N-nitrosodimethylamine (NDMA) impurities, which were considered to be carcinogenic. The aim of this study was to investigate the impact of regulatory intervention on use patterns of ranitidine-containing medicines and their therapeutic alternatives. Objectives: The aim was to study drug utilisation patterns of ranitidine and report discernible trends in treatment discontinuation and switching to alternative medications. Methods: This retrospective, population-based cohort study was conducted using primary care records from six European countries between 2017 and 2023. To explore drug utilisation patterns, we calculated (1) incident use of ranitidine, other H2RAs, and other alternative drugs for the treatment of gastric ulcer and/or gastric bleeding; (2) ranitidine discontinuation; and (3) switching from ranitidine to alternative drugs (H2RAs, proton-pump inhibitors [PPIs], and other medicinal products for acid-related disorders). Results: During the study period, 385,273 new ranitidine users were observed, with most users being female and aged 18–74 years. Ranitidine was the most commonly prescribed H2RA in the pre-referral period (September 2017–August 2019), with incidence rates between 0.8 and 9.0/1000 person years (PY). A steep decline to 0.3–3.8/1000 PY was observed in the referral period (September 2019–March 2020), eventually dropping to 0.0–0.4/1000 PY in the post-referral period (April 2020–March 2022). Switching from ranitidine to alternative drugs increased in the post-referral period, with the majority of patients switching to PPIs. Discontinuation of ranitidine use ranged from 270 to 380/1000 users in 2017 and decreased over time. Conclusions:Ranitidine was commonly used prior to referral, but it was subsequently discontinued and replaced primarily with PPIs.</p

    Proteção biológica contra as principais pragas na cultura de tomate protegido no Oeste

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