On controllability of fractional positive continuous-time linear systems with delay

In the paper positive fractional continuous-time linear systems are considered. Positive fractional systems without delays and positive fractional systems with a single delay in control are studied. New criteria for approximate and exact controllability of systems without delays as well as a relative controllability criterion of systems with delay are established and proved. Numerical examples are presented for different controllability criteria. A practical application is proposed

Effect of Ozone Fumigation on Physiological Processes and Bioactive Compounds of Red-Veined Sorrel (Rumex sanguineus ssp. sanguineus)

The present study was designed to identify the effects of ozone fumigation of red-veined sorrel plants on the selected physiological parameters and contents of bioactive compounds in the plant leaves. Sorrel plants grown in a pot experiment were subjected, at the final stage of growth, to ozone fumigation at a concentration of 1 ppm (mg m−3) for one, three, five, seven, and 10 min. The ozone treatment was followed with measurements performed one, four, and eight days later. The relative chlorophyll content in the leaves and selected chlorophyll fluorescence parameters (maximum quantum yield of PSII photochemistry, the maximum quantum yield of primary photochemistry and the performance index) and gas exchange parameters were assessed (net photosynthetic rate, transpiration rate, stomatal conductance, and intercellular CO2 concentration). By using the same leaves, the plant material was also assessed for the contents of bioactive compounds (total polyphenols) and for antioxidant properties (ABTS and DPPH assays). The ozone treatment did not produce adverse changes in the physiological parameters of the sorrel plants. Furthermore, no visible damage to the leaves was observed. On the other hand, the ozone fumigation induced the phenomenon of elicitation as a result of which it was observed that the ozone-treated sorrel plants had higher total polyphenol contents and greater antioxidant potential, compared to the plants of the same species grown in a traditional way without the ozone fumigation. Application of ozone fumigation in the production of Rumex sanguineus is associated with increased bioactive potential of the raw material obtained