The absorption, desorption, and volatility of three dinitroaniline herbicides in soil

The adsorption, desorption, and volatility of dinitramine (N4,N4- diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine), fluchloralin (N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-trifluoromethyl aniline), and profluralin (N-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl- 10-toluidine) were investigated in soil. Batch adsorption experiments were conducted on four Tennessee soils that had been subjected to various chemical treatments. In one set of extractions soils were sequentially extracted with solvents of increasing polarity. The solvents, the components removed and the change in adsorption relative to nontreated samples of the soils were as follows; ether-waxes and oils-(+22.0%); ethanol-resins-(+34.3%); water polysaccharides-(+ 0.8%); 2% HCl-hemicellulose-(+38.2%); and 80% H2SO4- cellulose-(+77.2%). In a second set of extractions the following solvents, the components removed and the effect on adsorption relative to the nontreated samples of the soils were as follows; 35% H2O2-organic matter-(-21.3%); sodium [citrate-dithionite-bicarbonate]-free iron oxides-(+44.0%); 35% H2O2 + sodium [citrate-dithionite-bicarbonate]- organic matter & free iron oxides -(+576.5%). Adsorption was directly related to the soils\u27 organic matter content and the length of the aniline sidechain. The proposed bonding mechanism for adsorption of the three dinitroanilines in soil is a combination of van der Waals-London interactions reinforced by hydrophobic bonding. Desorption of the three herbicides showed that profluralin was held with a greater force than dinitramine or fluchloralin. The desorption from soils was inversely related to the soil\u27s organic matter content. Average percent of the adsorbed herbicides desorbed by the five rinses was 32.4, 31.0, and 15.1% for dinitramine, fluchloralin, and profluralin. The effects of herbicidal properties, herbicide rates (12.5 and 25 μg/50 g), soil moisture (25, 50, 75, and 100% of field capacity-FC) and temperature (greenhouse-average maximum daytime temperature 38°C, laboratory-average maximum temperature 25°C) on volatilization of herbicides from soil were investigated. The average loss of herbicides 14 days after application for the 12.5 yg rate was 43.1, 23.9, and 17.4% for dinitramine, fluchloralin, and profluralin, respectively. Slightly lower values (37.7, 21.7, and 16.0%) were observed for the 25 μg rate. Increasing the soil moisture content increased volatilization substantially for all three herbicides. For example, profluralin loss increased from 23.5% at 25% of FC to 56.3% at FC. Generally no statistical difference in loss was recorded between the greenhouse and laboratory samples. This was due to the greenhouse samples being in a dry state for longer periods of time than the laboratory samples. Coefficients of determination (R-Square) obtained from a multiple regression technique were used to estimate the variability of herbicide loss caused by the parameters herbicides, moisture, temperature in the volatility study. The terms in the analysis included the linear, interaction, and square of the linear terms of herbicides (H), moisture (M), and temperature (T). A three variable model (H H2 M2) explained 89% of the variation for the 12.5 yg rate while a four variable model (H HT H2 M2) explained 86% of the variation for the 25 μg rate

The movement; sorption, loss and chemical distribution of arsenic-74 labeled disodium methanearsonate in some Tennessee soils

Radioactive 74As disodium methanearsonate (DSMA-74As) was used as a resentative compound of the methanearsonate family to study their fate and behavior in soil systems. This compound was produced in the laboratory. Five samples of 4 Tennessee soils of various chemical, physical, and mineralogical properties were used in this study. Sorption of DSMA-74As was studied by employment of the batch equilibration technique. Various soil properties (pH, percent clay content, CEC, organic matter content) were related to the soil sorption of DSMA-74As in this study. Imposed conditions (alteration of soil pH, phosphorus con-tent) of selected soil properties were related to the soil sorption of DSMA-74As. Using laboratory prepared soil columns the leachability and distribution of DSMA-74As were determined in the soils and the effect of the imposed conditions were measured. Determination of microbial or chemical induced evolution of gaseous arsenic under imposed conditions of organic matter and moisture was investigated. The distribution of sorbed DSMA-74As in the soil was determined by a modified phosphorus procedure. Soils with high clay content and with kaolinite as their major component sorbed the greatest quantities of DSMA-74As from solutions containing DSMA-74As. The effect of organic matter on sorption could not be measured directly, but it appears to have a positive effect on sorption of DSMA-74As. Cation exchange capacity apparently had no direct effect on sorption. In most cases the amount of DSMA-74As leached was inversely proportional to the sorption capacity of the soils. The soils with the least amount of clay leached the greatest quantities of DSMA-74As. Phosphorus reduced the ability of soil to sorb DSMA-74As quite dramat-ically in the batch equilibration experiments and in the soil columns. Acid treatments generally increased the ability of the soil to retain DSMA-74As. Sorption of DSMA-74As was found to be more dependent upon soil texture and mineralogical composition than pH. Gaseous arsenic evolution was greatest from soils that had received an exogeneous carbon source and maintained under reduced conditions. The chemical distribution of DSMA-74As in the soils studied showed that Fe arsenate was the predominant form and Al arsenate was the second most predominant form

The Relationship between Instructional Leadership Practices and Leadership Self-Efficacy of School Leaders

With educational reform focused on school accountability, principals must attend to tasks that lead to school improvement. Identifying such tasks as instructional leadership practices and gaining a more comprehensive understanding of instructional leadership practices through leadership self-efficacy may contribute to school improvement. Thus, the purpose of this quantitative study was to investigate instructional leadership practices and the degree to which these practices predict the leadership self-efficacy of school leaders. Participants in the survey were 100 principals and assistant principals of public schools in the southeastern United States, spanning 18 school districts, and 180 schools. Findings indicated instructional leadership practices of school leaders predict their leadership self-efficacy. More specifically, for every one unit increase in the area Supervising and Evaluating Instruction, self-efficacy increases by β = .321 standard deviations. Likewise, for every one unit increase in Monitoring Student Progress subscale, self-efficacy increases by β = .302 standard deviations. Additionally, there were statistically significant differences in the leadership self-efficacy of principals and assistant principals, t = 2.165, p =.033. Educational leaders and key constituents may consider these results for reflection on practice as well as professional learning for skill development to attain school improvement. Recommendations for future research include expansion of the population to include participants in other locations as well as the inclusion of additional instructional leadership practices

Stability of response characteristics of a Delphi panel: application of bootstrap data expansion

BACKGROUND: Delphi surveys with panels of experts in a particular area of interest have been widely utilized in the fields of clinical medicine, nursing practice, medical education and healthcare services. Despite this wide applicability of the Delphi methodology, there is no clear identification of what constitutes a sufficient number of Delphi survey participants to ensure stability of results. METHODS: The study analyzed the response characteristics from the first round of a Delphi survey conducted with 23 experts in healthcare quality and patient safety. The panel members had similar training and subject matter understanding of the Malcolm Baldrige Criteria for Performance Excellence in Healthcare. The raw data from the first round sampling, which usually contains the largest diversity of responses, were augmented via bootstrap sampling to obtain computer-generated results for two larger samples obtained by sampling with replacement. Response characteristics (mean, trimmed mean, standard deviation and 95% confidence intervals) for 54 survey items were compared for the responses of the 23 actual study participants and two computer-generated samples of 1000 and 2000 resampling iterations. RESULTS: The results from this study indicate that the response characteristics of a small expert panel in a well-defined knowledge area are stable in light of augmented sampling. CONCLUSION: Panels of similarly trained experts (who possess a general understanding in the field of interest) provide effective and reliable utilization of a small sample from a limited number of experts in a field of study to develop reliable criteria that inform judgment and support effective decision-making

Critical processes and performance measures for patient safety systems in healthcare institutions: a Delphi study

This dissertation study presents a conceptual framework for implementing and assessing patient safety systems in healthcare institutions. The conceptual framework consists of critical processes and performance measures identified in the context of the 2003 Malcolm Baldrige National Quality Award (MBNQA) Health Care Criteria for Performance Excellence. Methodology: The Delphi technique for gaining consensus from a group of experts and forecasting significant issues in the field of the Delphi panel expertise was used. Data collection included a series of questionnaires where the first round questionnaire was based on literature review and the MBNQA criteria for excellence in healthcare, and tested by an instrument review panel of experts. Twenty-three experts (MBNQA healthcare reviewers and senior healthcare administrators from quality award winning institutions) representing 18 states participated in the survey rounds. The study answered three research questions: (1) What are the critical processes that should be included in healthcare patient safety systems? (2) What are the performance measures that can serve as indicators of quality for the processes critical for ensuring patient safety? (3) What processes will be critical for patient safety in the future? The identified patient safety framework was further transformed into a patient safety tool with three levels: basic, intermediate, and advanced. Additionally, the panel of experts identified the major barriers to the implementation of patient safety systems in healthcare institutions. The identified "top seven" barriers were directly related to critical processes and performance measures identified as "important" or "very important" for patient safety systems in the present and in the future. This dissertation study is significant because the results are expected to assist healthcare institutions seeking to develop high quality patient safety programs, processes and services. The identified critical processes and performance measures can serve as a means of evaluating existing patient safety initiatives and guiding the strategic planning of new safety processes. The framework for patient safety systems utilizes a systems approach and will support healthcare senior administrators in achieving and sustaining improvement results. The identified patient safety framework will also assist healthcare institutions in using the MBNQA Health Care Criteria for Performance Excellence for self-assessment and quality improvement

Autoregressive Distributed Lag (ARDL) Analysis of Foreign Portfolio Investments Determination in Nigeria

This study investigates the key macroeconomic variables determining foreign portfolio inflows (FPI) to Nigeria using the autoregressive distributed lag procedure that includes the bounds test of cointegration and error correction mechanism applied against time-series Nigerian data from 1986 through 2019. The results reveal the existence of long-run equilibrium relationship between FPI and exchange rate (EXR), inflation (INF), interest rate (INT), real GDP, and Tax (TXR). Short-run errors are adjusted at a speed of 77.87% per annum, in the long-run. Causality is found to jointly-flow from the explanatory variables to FPI inflows. In all the model estimations - autoregressive, short- and long-runs, exchange rate exerted negative and significant effect on FPIR. Inflation and tax significantly affected FPI inflows to Nigeria. Growth in real GDP and interest rate positively influenced FPIR, but not significantly. The results indicate that the major determinants of FPI inflows are exchange rates, inflation, and tax

Are Electrons Oscillating Photons, Oscillating “Vacuum," or Something Else? The 2015 Panel Discussion: An Unprecedented Engineering Opportunity: A Dynamical Linear Theory of Energy as Light and Matter

Platform: What physical attributes separate EM waves, of the enormous band of radio to visible to x-ray, from the high energy narrow band of gamma-ray? From radio to visible to x-ray, telescopes are designed based upon the optical imaging theory; which is an extension of the Huygens-Fresnel diffraction integral. Do we understand the physical properties of gamma rays that defy us to manipulate them similarly? One demonstrated unique property of gamma rays is that they can be converted to elementary particles (electron and positron pair); or a particle-antiparticle pair can be converted into gamma rays. Thus, EM waves and elementary particles, being inter-convertible; we cannot expect to understand the deeper nature of light without succeeding to find structural inter-relationship between photons and particles. This topic is directly relevant to develop a deeper understanding of the nature of light; which will, in turn, help our engineers to invent better optical instruments

A systematic scoping review of study methodology for randomized controlled trials investigating probiotics in athletic and physically active populations

Background: The purported ergogenic and health effects of probiotics have been a topic of great intrigue among researchers, practitioners, and the lay public alike. There has also been an increased research focus within the realm of sports science and exercise medicine on the athletic gut microbiota. However, compared to other ergogenic aids and dietary supplements, probiotics present unique study challenges. The objectives of this systematic scoping review were to identify and characterize study methodologies of randomized controlled trials investigating supplementation with probiotics in athletes and physically active individuals. Methods: Four databases (MEDLINE, CINAHL, Cochrane CENTRAL, and Cochrane Database of Systematic Reviews) were searched for randomized controlled studies involving healthy athletes or physically active individuals. An intervention with probiotics and inclusion of a control and/or placebo group were essential. Only peer-reviewed articles in English were considered, and there were no date restrictions. Results were extracted and presented in tabular form to detail study protocols, characteristics, and outcomes. Bias in randomized controlled trials was determined with the RoB 2.0 tool. Results: A total of 45 studies were included in the review, with 35 using a parallel group design and 10 using a cross-over design. Approximately half the studies used a single probiotic and the other half a multi-strain preparation. The probiotic dose ranged from 2 × 108 to 1 × 1011 colony forming units daily, and the length of intervention was between 7 and 150 days. Fewer than half the studies directly assessed gastrointestinal symptoms, gut permeability, or the gut microbiota. The sex ratio of participants was heavily weighted toward males, and only 3 studies exclusively investigated females. Low-level adverse events were reported in only 2 studies, although the methodology of reporting varied widely. The risk of bias was generally low, although details on randomization were lacking in some studies. Conclusion: There is a substantial body of research on the effects of probiotic supplementation in healthy athletes and physically active individuals. Considerable heterogeneity in probiotic selection and dosage as well as outcome measures has made clinical and mechanistic interpretation challenging for both health care practitioners and researchers. Attention to issues of randomization of participants, treatments and interventions, selection of outcomes, demographics, and reporting of adverse events will facilitate more trustworthy interpretation of probiotic study results and inform evidence-based guidelines