53 research outputs found

    Social Factors in P2P Energy Trading Using Hedonic Games

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    Lately, the energy communities have gained a lot of attention as they have the potential to significantly contribute to the resilience and flexibility of the energy system, facilitating widespread integration of intermittent renewable energy sources. Within these communities the prosumers can engage in peer-to-peer trading, fostering local collaborations and increasing awareness about energy usage and flexible consumption. However, even under these favorable conditions, prosumer engagement levels remain low, requiring trading mechanisms that are aligned with their social values and expectations. In this paper, we introduce an innovative hedonic game coordination and cooperation model for P2P energy trading among prosumers which considers the social relationships within an energy community to create energy coalitions and facilitate energy transactions among them. We defined a heuristic that optimizes the prosumers coalitions, considering their social and energy price preferences and balancing the energy demand and supply within the community. We integrated the proposed hedonic game model into a state-of-the-art blockchain-based P2P energy flexibility market and evaluated its performance within an energy community of prosumers. The evaluation results on a blockchain-based P2P energy flexibility market show the effectiveness in considering social factors when creating coalitions, increasing the total amount of energy transacted in a market session by 5% compared with other game theory-based solutions. Finally, it shows the importance of the social dimensions of P2P energy transactions, the positive social dynamics in the energy community increasing the amount of energy transacted by more than 10% while contributing to a more balanced energy demand and supply within the community.Comment: to be submitted to journa

    Organic fertilizer effect on lettuce (Lactuca sativa L.) cultivated in nutrient film technology

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    The survey was carried out in the Research Centre for the study of food products quality “HORTINVEST” between 2014-2015 using the Nutrient Film Technology (NFT) for the cultivation of lettuce. Three lettuce cultivars were used: Markies, Lollo bionda and Lollo rosa, together with three types of fertilizers: two organic fertilizers and a chemical one. Biometrical measurements on lettuce growth were conducted; also at the end of the cultivation cycle biochemical measurements were performed in order to assess plant quality. Also correlations between various biometrical parameters and influencing vegetal factors were settled. The results led towards gains in the plant growth rate, in the development of the leaf number and eventually in the production growth. For all lettuce varieties under research the total plant mass was higher due to organic fertilizers in comparison with plants under chemical fertilizer treatment. The plants organically fertilized proved to be superior as to the biochemical quality. Research was carried out in order to assess the quantitative and qualitative feedback of lettuce cultivated in Nutrient Film Technology (NFT) to various organic fertilizers which might replace chemical fertilizers

    Consistency of the Disposition Index in the Face of Diet Induced Insulin Resistance: Potential Role of FFA

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    Objective Insulin resistance induces hyperinsulinemic compensation, which in turn maintains almost a constant disposition index. However, the signal that gives rise to the hyperinsulinemic compensation for insulin resistance remains unknown. Methods In a dog model of obesity we examined the possibility that potential early-week changes in plasma FFA, glucose, or both could be part of a cascade of signals that lead to compensatory hyperinsulinemia induced by insulin resistance. Results Hypercaloric high fat feeding in dogs resulted in modest weight gain, and an increase in adipose tissue with no change in the non-adipose tissue size. To compensate for the drop in insulin sensitivity, there was a significant rise in plasma insulin, which can be attributed in part to a decrease in the metabolic clearance rate of insulin and increased insulin secretion. In this study we observed complete compensation for high fat diet induced insulin resistance as measured by the disposition index. The compensatory hyperinsulinemia was coupled with significant changes in plasma FFAs and no change in plasma glucose. Conclusions We postulate that early in the development of diet induced insulin resistance, a change in plasma FFAs may directly, through signaling at the level of ÎČ-cell, or indirectly, by decreasing hepatic insulin clearance, result in the observed hyperinsulinemic compensation

    Variation of the Chemical Element Content in the Dealu Bujorului Vineyard Soil

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    The purpose of this study is to know better the concentration of chemical elements in the soil from Dealu Bujorului vineyard. The determination of the ten elements from the soil samples was performed using ICP-MS. The results showed diverse patterns of cadmium, lead, uranium, mercury, arsenic, strontium, cobalt, copper, nickel and chromium, all the elemental content studied were under the maximum limit admitted, except for copper (average 356.03 mg/kg while M.L.A. = 20 mg/kg)

    Results on the use of bacterial biopreparations (biological fertilizers) in agricultural crops in Research and Development Stations for Agriculture, Romania

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    The development and use of strategies for organic fertilization of agricultural crops will lead to a decomposition of insoluble elements in the soil structure, which will lead to an increase in the number of soluble mineral elements in the soil structure, which will lead to significant plant growth and of agricultural production. Soil pollution with chemical elements has led to an increase in pH from a basic / neutral to an acid one. Soil acidification causes a decrease in agricultural production, a decrease in plant resistance to certain pests of soil structure, but especially soil pollution, groundwater with certain chemical elements found in the structure of fertilizers. Thus, following the research carried out within the research-development stations for agriculture in Romania, it was proved that the lots fertilized with biological fertilizer had a much higher production than the lots fertilized chemically

    Economic advantages of using bacterial biopreparations in agricultural crops

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    The ecological, genetic, biological approach proposed by agricultural specialists in order to protect plants and crops has a role in reducing the impact of pests through the process of selection and improvement of genetic resources in the processes of planting, development and introduction of biological means to combat pests in agricultural ecosystems. The strategies proposed by the specialists in the agricultural field aim not at the total extermination of the pests from the agricultural crops but at keeping the pest populations at the optimal damage threshold. The most important advantages of these biological processes are those of the evolutionary stability of the crop systems, the ecological stabilization of the pest and crop populations as well as the assurance of a superior quality of the resulting agricultural products.The present paper aims to present the main advantages of using bacterial biopreparations in agricultural ecosystems (research conducted in agricultural research stations in Romania), reducing soil pollution, environmental crops, use of alternative fertilization and cultivation technologies as well as obtaining additional, ecological productions.The aim of this paper is to present the economic advantages of using bacterial biopreparations in agricultural research and development stations, reducing costs in agriculture and the processes that these bacterial biopreparations have on the agricultural ecosystem, the environment and humans and animals

    Exenatide can reduce glucose independent of islet hormones or gastric emptying

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    Exenatide is a long-acting glucagon-like peptide-1 (GLP-1) mimetic used in the treatment of type 2 diabetes. There is increasing evidence that GLP-1 can influence glycemia not only via pancreatic (insulinotropic and glucagon suppression) and gastric-emptying effects, but also via an independent mechanism mediated by portal vein receptors. The aim of our study was to investigate whether exenatide has an islet- and gastric-independent glycemia-reducing effect, similar to GLP-1. First, we administered mixed meals, with or without exenatide (20 ÎŒg sc) to dogs. Second, to determine whether exenatide-induced reduction in glycemia is independent of slower gastric emptying, in the same animals we infused glucose intraportally (to simulate meal test glucose appearance) with exenatide, exenatide + the intraportal GLP-1 receptor antagonist exendin-(9-39), or saline. Exenatide markedly decreased postprandial glucose: net 0- to 135-min area under the curve = +526 ± 315 and −536 ± 197 mg·dl−1·min−1 with saline and exenatide, respectively (P < 0.05). Importantly, the decrease in plasma glucose occurred without a corresponding increase in postprandial insulin but was accompanied by delayed gastric emptying and lower glucagon. Significantly lower glycemia was induced by intraportal glucose infusion with exenatide than with saline (92 ± 1 vs. 97 ± 1 mg/dl, P < 0.001) in the absence of hyperinsulinemia or glucagon suppression. The exenatide-induced lower glycemia was partly reversed by intraportal exendin-(9-39): 95 ± 3 and 92 ± 3 mg/dl with exenatide + antagonist and exenatide, respectively (P < 0.01). Our results suggest that, similar to GLP-1, exenatide lowers glycemia via a novel mechanism independent of islet hormones and slowing of gastric emptying. We hypothesize that receptors in the portal vein, via a neural mechanism, increase glucose clearance independent of islet hormones

    Portal glucose infusion-glucose clamp measures hepatic influence on postprandial systemic glucose appearance as well as whole body glucose disposal

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    The full impact of the liver, through both glucose production and uptake, on systemic glucose appearance cannot be readily studied in a classical glucose clamp because hepatic glucose metabolism is regulated not only by portal insulin and glucose levels but also portal glucose delivery (the portal signal). In the present study, we modified the classical glucose clamp by giving exogenous glucose through portal vein, the “portal glucose infusion (PoG)-glucose clamp”, to determine the net hepatic effect on postprandial systemic glucose supply along with the measurement of whole body glucose disposal. By comparing systemic rate of glucose appearance (Ra) with portal glucose infusion rate (PoGinf), we quantified “net hepatic glucose addition (NHGA)” in the place of endogenous glucose production determined in a regular clamp. When PoG-glucose clamps (n = 6) were performed in dogs at basal insulinemia and hyperglycemia (∌150 mg/dl, portal and systemic), we measured consistently higher Ra than PoGinf (4.2 ± 0.6 vs. 2.9 ± 0.6 mg·kg−1·min−1 at steady state, P < 0.001) and thus positive NHGA at 1.3 ± 0.1 mg·kg−1·min−1, identifying net hepatic addition of glucose to portal exogenous glucose. In contrast, when PoG-glucose clamps (n = 6) were performed at hyperinsulinemia (∌250 pmol/l) and systemic euglycemia (portal hyperglycemia due to portal glucose infusion), we measured consistently lower Ra than PoGinf (13.1 ± 2.4 vs. 14.3 ± 2.4 mg·kg−1·min−1, P < 0.001), and therefore negative NHGA at −1.1 ± 0.1 mg·kg−1·min−1, identifying a switch of the liver from net production to net uptake of portal exogenous glucose. Steady-state whole body glucose disposal was 4.1 ± 0.5 and 13.0 ± 2.4 mg·kg−1·min−1, respectively, determined as in a classical glucose clamp. We conclude that the PoG-glucose clamp, simulating postprandial glucose entry and metabolism, enables simultaneous assessment of the net hepatic effect on postprandial systemic glucose supply as well as whole body glucose disposal in various animal models (rodents, dogs, and pigs) with established portal vein catheterization

    Identification of Daily Living Recurrent Behavioral Patterns Using Genetic Algorithms for Elderly Care

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    A person’s routine is a sequence of activities of daily living patterns recurrently performed. Sticking daily routines is a great tool to support the care of persons with dementia, and older adults in general, who are living in their homes, and also being useful for caregivers. As state-of-the-art tools based on self-reporting are subjective and rely on a person’s memory, new tools are needed for objectively detecting such routines from the monitored data coming from wearables or smart home sensors. In this paper, we propose a solution for detecting the daily routines of a person by extracting the sequences of recurrent activities and their duration from the monitored data. A genetic algorithm is defined to extract activity patterns featuring small differences that relate to the day-to-day contextual variations that occur in a person’s daily routine. The quality of the solutions is evaluated with a probabilistic-based fitness function, while a tournament-based strategy is employed for the dynamic selection of mutation and crossover operators applied for generating the offspring. The time variability of activities of daily living is addressed using the dispersion of the values of duration of that activity around the average value. The results are showing an accuracy above 80% in detecting the routines, while the optimal values of population size and the number of generations for fitness function evolution and convergence are determined using multiple linear regression analysis
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