Glyphosate, one of the most widely used herbicides, plays an important role in controlling weeds and ensuring crop production. While using glyphosate, adjuvants are commonly added to improve its deposition on weeds and control efficacy. However, changes in weed leaf surface characteristics may reduce glyphosate penetration and contribute to evolved glyphosate resistance. Therefore, it is significant to introduce an improved method for regularizing leaf surface characterization and guide adjuvant selection to improve glyphosate efficacy. In this work, surface characteristics of typical weed leaves have been systematically investigated by 3D surface analysis and scanning electron microscopy, finally quantified by apparent surface free energy (ASFE) due to its comprehensive and quantitative evaluation of leaf surfaces. Moreover, the relationship between the weed leaf surface characteristics and the retention of glyphosate on weeds was established, further related to the control efficacy against weeds. To maximize the utilization rate of glyphosate, the types and concentrations of adjuvants should be regulated according to the ASFE of weeds. Our findings not only regularize the surface properties of weed leaves but also reveal their influencing mechanism on the deposition and biological activity of glyphosate, which provide effective guidance for the use of glyphosate.
Grid-connected renewable energy with high penetration rate puts forward higher requirements for power system frequency regulation. This paper designs a PI control loop based on the reliability index of Expected Energy not Supplied (EENS). The control loop is combined with the traditional primary and secondary frequency regulation model to realize the preventive adjustment of the active power output of conventional generators during normal operation. The proposed PI control loop takes the minimum EENS of the system as the control reference value, and the real-time prediction value of EENS as the feedback, and uses the deviation between the two as the basis to redistribute power outputs of dispatchable units. A method for determining feasible parameter ranges of the PI controller based on the Jury criterion is proposed. It is verified by simulation that the proposed control loop can effectively improve the frequency response effect.
Objective To examine the total non-accidental mortality burden attributable to ambient temperatures and assess the effect modification of the burden by specific causes of death and individual characteristics in a high plateau area in southwest China. Methods Using daily mortality and meteorological data from 2009 to 2016, we applied a quasi-Poisson model combined with a distributed lag non-linear model to estimate the temperature–mortality association with the assessment of attributable fraction and number. We calculated attributable fractions and deaths with 95% empirical CIs (eCIs), that were due to cold and heat, defined as temperatures below and above the median temperature, and for mild and extreme temperatures, defined by cut-offs at the 2.5th and 97.5th temperature percentiles. Results We analysed 89 467 non-accidental deaths; 4131 were attributable to overall temperatures, with an attributable fraction of 4.75% (95% eCI 2.33% to 6.79%). Most of the mortality burden was caused by cold (4.08%; 0.86% to 7.12%), whereas the burden due to heat was low and non-significant (0.67%; −2.44% to 3.64%). Extreme cold (1.17%; 0.58% to 1.69%) was responsible for 24.6% (ie, 1.17% divided by 4.75%) of the total death burden. In the stratification analyses, attributable risk due to cold was higher for cardiovascular than respiratory disease (6.18% vs 3.50%). We found a trend of risk of increased death due to ambient temperatures with increasing age, with attributable fractions of 1.83%, 2.27% and 6.87% for age ≤64, 65–74 and ≥75 years old, respectively. The cold-related burden was slightly greater for females, farmers, ethnic minorities and non-married individuals than their corresponding categories. Conclusions Most of the burden of death was attributable to cold, and specific causes and individual characteristics might modify the mortality burden attributable to ambient temperatures. The results may help make preventive measures to confront climate change for susceptible population in this region.
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