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In Australia, trifluralin is one of the commonly used herbicides to manage annual grasses and some broadleaf weeds. However, it may have some ecosystem impacts such as high toxicity to terrestrial and aquatic life, so it is vital to monitor the degradation of trifluralin for a considerable period for environmental safety. For risk assessment purposes, it is necessary to estimate the half-life of trifluralin, which is often evaluated using derived mathematical dissipation models. In the literature, bi-exponential (BEXP) and gamma models were suggested for modelling the dissipation of trifluralin in soil. Both models provide the half-life estimate without discussing the uncertainty of the estimate, which is a shortcoming in the literature. In this paper, we used simulation to illustrate the importance of estimate's uncertainty (standard error) and demonstrated a method to compute the standard error for the half-life estimate mathematically for kinetic dissipation models. Later, we evaluated the performance of the two suggested models using statistical indices. The computation of the half-life and the standard error of the half-life estimate were discussed. This allows us to describe the inference of the half-life parameter and determine whether the half-life estimates are significantly different against the co-variate (moisture) levels. We demonstrated the method to calculate the standard error of the half-life of trifluralin, which allows us to determine the statistical difference between the estimates. In this study, we found that the half-life of trifluralin in soil tends to increase with increasing moisture levels, and the half-life of trifluralin in soil with 100% moisture level is significantly greater than 40% and 70% moisture levels. Our findings suggest that soil moisture levels should be carefully considered before trifluralin application to minimize the non-target environmental damage. [Display omitted] • BEXP and gamma models have been considered to investigate the trifluralin dissipation. • A simulation study illustrated the importance of the standard error of half-life. • Provided mathematical computation of the standard error of the half-life. • The soil moisture levels influenced the half-life estimates of trifluralin. [ABSTRACT FROM AUTHOR]

Background: Automated eHealth Web-based research trials offer people an accessible, confidential opportunity to engage in research that matters to them. eHealth trials may be particularly useful for sensitive issues when seeking health care may be accompanied by shame and mistrust. Yet little is known about people’s early engagement with eHealth trials, from recruitment to preintervention autoregistration processes. A recent randomized controlled trial that tested the effectiveness of an eHealth safety decision aid for New Zealand women in the general population who experienced intimate partner violence (isafe) provided the opportunity to examine recruitment and preintervention participant engagement with a fully automated Web-based registration process. The trial aimed to recruit 340 women within 24 months. Objective: The objective of our study was to examine participant preintervention engagement and recruitment efficiency for the isafe trial, and to analyze dropout through the registration pathway, from recruitment to eligibility screening and consent, to completion of baseline measures. Methods: In this case study, data collection sources included the trial recruitment log, Google Analytics reports, registration and program metadata, and costs. Analysis included a qualitative narrative of the recruitment experience and descriptive statistics of preintervention participant engagement and dropout rates. A Koyck model investigated the relationship between Web-based online marketing website advertisements (ads) and participant accrual. Results: The isafe trial was launched on September 17, 2012. Placement of ads in an online classified advertising platform increased the average number of recruited participants per month from 2 to 25. Over the 23-month recruitment period, the registration website recorded 4176 unique visitors. Among 1003 women meeting eligibility criteria, 51.55% (517) consented to participate; among the 501 women who enrolled (consented, validated, and randomized), 412 (82.2%) were accrued (completed baseline assessments). The majority (n=52, 58%) of the 89 women who dropped out between enrollment and accrual never logged in to the allocated isafe website. Of every 4 accrued women, 3 (314/412, 76.2%) identified the classified ad as their referral source, followed by friends and family (52/412, 12.6%). Women recruited through a friend or relative were more likely to self-identify as indigenous Māori and live in the highest-deprivation areas. Ads increased the accrual rate by a factor of 74 (95% CI 49–112). Conclusions: Print advertisements, website links, and networking were costly and inefficient methods for recruiting participants to a Web-based eHealth trial. Researchers are advised to limit their recruitment efforts to Web-based online marketplace and classified advertising platforms, as in the isafe case, or to social media. Online classified advertising in “Jobs–Other–volunteers” successfully recruited a diverse sample of women experiencing intimate partner violence. Preintervention recruitment data provide critical information to inform future research and critical analysis of Web-based eHealth trials. [ABSTRACT FROM AUTHOR]

Dissipation kinetics of atrazine and trifluralin in a clay loam soil was investigated in a laboratory incubation experiment under different temperature and moisture conditions. The soil was spiked with diluted atrazine and trifluralin concentrations at 4.50 and 4.25 mg/kg soil, respectively, the moisture content adjusted to 40, 70, and 100% of field capacity (FC) and then incubated in three climatic chambers at 10, 20, and 30 °C. For each of the herbicides, soil samples were collected at 0, 7, 21, 42, 70, and 105 days and analysed by Gas Chromatography-Electron Capture Detector (GC-ECD). A stochastic gamma model was used to model the dissipation of herbicides from the clay loam soil by incorporating environmental factors as covariates to determine half-life and days to complete dissipation. Results showed that temperature played a greater role on atrazine persistence than soil moisture; while the interaction effect of temperature and moisture was significant on the persistence of trifluralin over time. Atrazine dissipated more rapidly at 30 °C compared to 10 and 20 °C, with a half-life of 7.50 days and 326.23 days to reach complete dissipation. Rapid loss of trifluralin was observed at 70% moisture content when incubated at 30 °C, with a half-life of 5.80 days and 182.01 days to complete dissipation. It was observed that the half-life of both herbicides tended to double with every 10 °C decreases of temperature over the range tested. The model indicated that both atrazine and trifluralin have the potential to persist in clay loam soil for several years at temperature ≤20 °C; which could potentially affect following crops in rotation. Persistence of atrazine and trifluralin in clay loam soil. [Display omitted] • Atrazine and trifluralin loss in clay loam soil was investigated using gamma model. • Environmental factors e.g. effect of temperature and moisture were incorporated. • Herbicide rate of loss, half-life and complete dissipation timeline was calculated. • Half-lives of atrazine and trifluralin doubled with 10 °C drop in temperature. • Both herbicides could persist in clay loam soil for several years at ≤ 20 °C. Application of gamma distribution model indicated that half-life of atrazine and trifluralin tended to double with every 10 °C drop in temperature; with a potential to persist in clay loam soil for couple of years at ≤ 20 °C. [ABSTRACT FROM AUTHOR]