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Heart rate can reflect the vitality level and physiological status of oysters and can be used as a vital characteristic indicator to monitor the physiological metabolism level of oysters. This study aims to optimize the heart rate measurement technology during the survival and circulation process of Crassostrea hongkongensis and explore the survival of oysters. Taking C. hongkongensis as the research object,a linear mathematical model was used to determine the heart position of the oysters and the infrared heart rate measurement technology was optimized by combining infrared sensors and PowerLab devices. The effects of salinity fluctuations, linear induced dormancy,and storage period of oysters during the live circulation process were discussed. Effect of heart rate. Results: After pre-treatment with 6 mm drilling holes,temporary cultivation in seawater had little effect on the vitality of oysters. The survival rate still reached 100% on the 9th day. There was no significant difference in heart rate between 2 and 18 hours using the infrared measurement method (P>0.05); individual size,dry dew,salinity,and temperature all significantly affect the heart rate of oysters (P<0.05). The heart rate of oysters stored in seawater measured by infrared technology shows a significant upward trend over time (P<0.05). The heart rate of oysters exposed to storage at the end of the period increased and then decreased over time (P<0.05). Excessive abiotic stress can cause cardiac arrest,which may have adverse effects. Conclusion: Infrared measurement technology is suitable for measuring oyster heart rate. Changes in heart rate during the survival period effectively reflect the physiological state of oysters. Heart rate can be used as a vitality measurement indicator for oysters to stay alive without water. Research on the oyster survival monitoring system based on heart rate as an indicator has a certain reference significance. [ABSTRACT FROM AUTHOR]

A comparison between maximum quantum yield of PSII photochemistry (Fv/Fm) and chlorophyll fluorescence decrease ratio (Rfd) for low and high temperature resistance was assessed in a seasonal study of the acclimation in Pterocephalus lasiospermus. Analyzing the regression adjustment of both parameters and the lethal temperatures (LT50), Rfd resulted in being a more sensitive indicator for low and high temperature treatments, since the thermic resistance estimated with Rfd parameter was never higher than those estimated with Fv/Fm. Furthermore, the use of Fv/Fm led to an overestimation of the acclimation phenomena, with 6ºC of a maximum difference between both parameters. Using Rfd as the indicator parameter, P. lasiospermus acclimated to low temperatures but it kept on being a sensitive species (the lowest LT50 values only achieved-9.9 ± 0.3ºC). bserved (LT50 around 43.5ºC). Thus, according to Rfd evaluation of the thermic threshold, this species could be in risk of damage at low temperatures in this alpine ecosystem. [ABSTRACT FROM AUTHOR]

The article captures the main characteristics of the demographic dynamics in the influence area of Râmnicu Vâlcea city, between 1985 and 2007. In this respect, we analyzed the evolution in numbers of the population in the area of influence in the respective period, as well as a set of indicators such as birth rates, mortality rate, natural increase and the vitality index in order to identify the changes of quantitative and qualitative nature that influenced the mass of population in the area of influence during the period analyzed. [ABSTRACT FROM AUTHOR]

Laser-induced chlorophyll fluorescence (LICF) spectra and fluorescence induction kinetics (FIK) curves of wheat plant leaves treated with different concentrations (50, 100 and 200 ppm) of dimethoate are recorded. LICF spectra are recorded in the region of 650-780 nm using violet diode laser (405 nm) and FIK curve at 685 and 730 nm with red diode laser (635 nm) for excitation. The fluorescence intensity ratios (FIR) are determined from LICF spectra and vitality index (R) from FIK curves. These parameters along with photosynthetic pigment contents and growth parameters are used to analyze the effect of dimethoate on wheat plants. The result indicates that lower concentration of 50 ppm shows stimulatory response while higher concentrations of dimethoate are hazardous for growth, photosynthetic pigments and activity of wheat plants. [ABSTRACT FROM AUTHOR]

We used simulated microgravity to treat aged pea seeds, in order to observe its effect on seed vigour and related physiological properties. The result shows that microgravity obviously promotes the germination rate, vitality index, germination index, and keeps the activity of protective enzyme, with conductivity and the content of MDA decreased. These effects gradually disappeared for a certain period after the microgravity administration. [Copyright &y& Elsevier]