Comparative Analysis of Data using Machine Learning Algorithms: A hydroponics system use case

This paper makes a comparison of machine learning algorithms for the analysis of four hydroponic datasets. Data have been gathered daily from hydroponic systems to predict the output of the hydroponic systems. This research compares the per- formance of the federated split Learning, Deep neural network, extreme Gradient Boosting (XGBoost), and Linear regression algorithms on four different hydroponic systems. These algorithms have been used to analyze the datasets of Nutrient Film Technic (NFT), Floating (FL), Aggregate (AG) and Aeroponic (AER) hydroponic systems. The results have indicated the performance of each model for each hy- droponic system and how each algorithm have used the various multiple input fea- tures to make predictions of the onion bulb diameter and the errors encountered by each model. From the results obtained, it has been observed that the R square score is varied for each hydroponic system. This variation in the result has been also reflected in the Mean absolute errors obtained. This research determine which of the algorithms predict the optimal Onion bulb diameter(mm) using days after transplant(days), Temperature(oC), water consumption (Litres), Number of Leaves(NL), Nitrogen (mg/g), Phosphorus(mg/g),Potassium (mg/g), Calcium (mg/g), Magnesium (mg/g), Sulphur (mg/g), Sodium(mg/g) as independent variables. The results will be a guide in the choice of hydroponic system to adopt for food production based on the climatic parameters of the location, which is one of the numerous contributions of this research

Correlation of oleocanthal and oleacein concentration with pungency and bitterness in 'koroneiki' virgin olive oil

It is known that the organoleptic attributes of pungency and bitterness in olive oil are attributed to phenolic compounds. Recent research has demonstrated that oleocanthal, a secoiridoic phenolic, is a naturally occurring anti-inflammatory and neuroprotective agent, and that it elicits a throat stinging sensation through a specific TRPA1 receptor. Oleacein, a hydroxytyrosol derivative is considered as the most powerful antioxidant in olive oil and although it differs from oleocanthal only by one additional phenolic hydroxyl, organoleptically it is associated more with bitterness and less with pungency. The present study examined the correlations between oleocanthal and oleacein concentrations and the intensity of pungent and bitter sensations in a group of 21 virgin olive oil samples of the 'Koroneiki' cultivar, produced in a specific geographic region of Greece (Messini). The qualitative and quantitative determination of the chemical compounds was carried out by a new method based on quantitative 1H-NMR in CDCl3 at 600 MHz after extraction of olive oil with acetonitrile. The concentrations of the studied compounds ranged for oleocanthal between 34.6-154.6 mg/L (mean value 94.5±31.8 mg/L) and for oleacein between 11.5-191.9 mg/L (mean value 63.3±36.1 mg/L). The organoleptic assessment of the samples was performed by a trained sensory panel according to the IOC method. The values of the positive attributes were distributed between 0.40-2.65 (mean value 1.45±0.72) for bitterness, 1.50-3.70 (mean value 2.62±0.56) for pungency and 0.40-3.60 (mean value 2.14±0.82) for fruitiness. The results showed that there is a positive correlation (r=0.79, p≤0.05) between the concentration of oleocanthal and oleacein, and the intensity of pungency and bitterness, suggesting that virgin olive oils with intense organoleptic attributes may offer more health benefits. Moreover, a proposal for a new index for describing and quantifying the positive organoleptic attributes of virgin olive oils is discussed

Responses of sweet pepper (Capsicum annum L.) cultivated in a closed hydroponic system to variable calcium concentrations in the nutrient solution

BACKGROUND: The use of water containing calcium bicarbonate (Ca(HCO3)2) at excessively high concentrations in closed hydroponic crops can cause calcium ion (Ca2+) accumulation in the recycled nutrient solution (NS) and concomitantly negatively affect yield and product quality. The aim of the study was to determine maximum Ca2+ concentrations that do not harm the crop and to simulate the pattern of Ca2+ accumulation when the Ca2+ concentration in the irrigation water, and concomitantly in the replenishment nutrient solution (RNS), is excessive. In the current study, irrigation water containing 1.5, 3.0, 4.5 and 6.0 mmol L−1 Ca2+ was used to prepare the RNS supplied to pepper cultivated in a closed hydroponic system. RESULTS: At 1.5 mmol L−1 Ca2+, no Ca2+ accumulation was observed in the recirculating NS. However, at 3.0, 4.5 and 6.0 mmol L−1 in the irrigation water, the Ca2+ concentration in the recirculating NS, increased by the latter cropping stages to 17, 28 and 37 mmol L−1, corresponding to 6.4, 9.0 and 10.8 dS m−1. The accumulation of Ca2+ in the recirculating NS affected both tissue nutrient concentrations and uptake concentrations of Ca2+, sulphate ion (SO42−) and magnesium ion (Mg2+), but this was not the case for nitrogen (N) or potassium ion (K+). Growth, yield and plant water uptake were restricted at moderate (3.0 and 4.5 mmol L−1) and high (6.0 mmol L−1) external Ca2+ levels. CONCLUSION: In soilless pepper crops with zero discharge of fertigation effluents, the Ca2+ concentration in the irrigation water and the RNS should be lower than 3.0 mmol L−1 to avoid yield restrictions due to salinity. © 2021 Society of Chemical Industry. © 2021 Society of Chemical Industr

Responses of sweet pepper (Capsicum annum L.) cultivated in a closed hydroponic system to variable calcium concentrations in the nutrient solution

BACKGROUND: The use of water containing calcium bicarbonate (Ca(HCO3)2) at excessively high concentrations in closed hydroponic crops can cause calcium ion (Ca2+) accumulation in the recycled nutrient solution (NS) and concomitantly negatively affect yield and product quality. The aim of the study was to determine maximum Ca2+ concentrations that do not harm the crop and to simulate the pattern of Ca2+ accumulation when the Ca2+ concentration in the irrigation water, and concomitantly in the replenishment nutrient solution (RNS), is excessive. In the current study, irrigation water containing 1.5, 3.0, 4.5 and 6.0 mmol L−1 Ca2+ was used to prepare the RNS supplied to pepper cultivated in a closed hydroponic system. RESULTS: At 1.5 mmol L−1 Ca2+, no Ca2+ accumulation was observed in the recirculating NS. However, at 3.0, 4.5 and 6.0 mmol L−1 in the irrigation water, the Ca2+ concentration in the recirculating NS, increased by the latter cropping stages to 17, 28 and 37 mmol L−1, corresponding to 6.4, 9.0 and 10.8 dS m−1. The accumulation of Ca2+ in the recirculating NS affected both tissue nutrient concentrations and uptake concentrations of Ca2+, sulphate ion (SO42−) and magnesium ion (Mg2+), but this was not the case for nitrogen (N) or potassium ion (K+). Growth, yield and plant water uptake were restricted at moderate (3.0 and 4.5 mmol L−1) and high (6.0 mmol L−1) external Ca2+ levels. CONCLUSION: In soilless pepper crops with zero discharge of fertigation effluents, the Ca2+ concentration in the irrigation water and the RNS should be lower than 3.0 mmol L−1 to avoid yield restrictions due to salinity. © 2021 Society of Chemical Industry

Leaf antioxidant machinery stimulation by Meloidogyne javanica infestation: A case study on Cucumis melo seedlings

Following nematode infestation, leaf-localized responses are vital not only as early infection signs but also as an indication of actions required to preserve crop productivity. In this context, the leaf-level physiological responses of cantaloupe seedlings were evaluated after 40 consecutive days of cultivation under different Meloidogyne javanica juveniles (J2s) inoculation regimes (0, 100, and 850 J2s plant−1). Leaf growth parameters and photosynthetic pigments (chlorophyll, carotenoids) content were not affected by J2s infestation, while foliar Potassium concentration significantly declined. The RuBIsCo activase gene expression was negatively associated with the J2s inoculation level. Total flavonoids, total phenolics, lipid peroxidation indexes, phenylalanine ammonia-lyase activity, as well as, ascorbate peroxidase gene transcription, were higher in the inoculated plants (regardless of the J2s inoculant level). Taken together, present data indicate that J2s infestation impacts primarily the Potassium levels in leaves. Additionally, a substantial stimulation of the plant antioxidant machinery (independent of the nematode infestation intensity) is triggered. Finally, it was established that the transcriptional regulation of the RuBIsCo activase 1 gene under biotic stress has the capacity to be employed as a potential stress indicator marker

Leaf antioxidant machinery stimulation by Meloidogyne javanica infestation: A case study on Cucumis melo seedlings

Following nematode infestation, leaf-localized responses are vital not only as early infection signs but also as an indication of actions required to preserve crop productivity. In this context, the leaf-level physiological responses of cantaloupe seedlings were evaluated after 40 consecutive days of cultivation under different Meloidogyne javanica juveniles (J2s) inoculation regimes (0, 100, and 850 J2s plant−1). Leaf growth parameters and photosynthetic pigments (chlorophyll, carotenoids) content were not affected by J2s infestation, while foliar Potassium concentration significantly declined. The RuBIsCo activase gene expression was negatively associated with the J2s inoculation level. Total flavonoids, total phenolics, lipid peroxidation indexes, phenylalanine ammonia-lyase activity, as well as, ascorbate peroxidase gene transcription, were higher in the inoculated plants (regardless of the J2s inoculant level). Taken together, present data indicate that J2s infestation impacts primarily the Potassium levels in leaves. Additionally, a substantial stimulation of the plant antioxidant machinery (independent of the nematode infestation intensity) is triggered. Finally, it was established that the transcriptional regulation of the RuBIsCo activase 1 gene under biotic stress has the capacity to be employed as a potential stress indicator marker