Conservation Tillage, Pesticide Use, and Biotech Crops in the U.S.A.

This paper presents the first part of an ongoing project whose objective is to present a long term relationship between conservation tillage, adoption of GE crops and pesticide use for major crops in the United States. In addition, the project aims to provide some innovative tests on causality using a panel data set. This paper presents preliminary results for soybeans.conservation tillage, biotechnology, genetically engineered crops, soybeans, herbicides, Environmental Economics and Policy, Farm Management, Production Economics,

Impact of GE Crop Adoption on Quality-Adjusted Herbicide Use in U.S. Corn Production

This paper presents findings on the use of HT corn and quality-adjusted herbicide use for 12 key corn producing states using a panel data set for 1986-2008. Our preliminary findings indicate an insignificant impact of HT corn on herbicide use, conditioning or accounting for HT corn with other important drivers of corn herbicide use: HT soy, corn output price, glyphoste price, nonherbicide glyponsate price, and percentage of continuous corn and low-till corn. However, we find a positive and significant impact of HT corn on herbicide use in selected states, using regional interaction terms. We use econometric techniques to avoid spurious regression results. Other preliminary runs indicated that the results hold when running the US and regional interactions on 1986-2006 and 1986-2007 data.HT-corn, herbicides, weed resistance, glyphosate, corn, Environmental Economics and Policy, Farm Management, Production Economics,

Evaluating a visual timeline methodology for appraisal and coping research

Theoretical models of stress have become increasingly sophisticated, recognizing the importance of context and history, yet the principal data-gathering method used by researchers remains the self-report questionnaire, a method which is conspicuously ill suited to obtaining data which would allow for exploration of these factors. In this article, we explore the use of visual methods as an alternative to traditional methods, presenting the findings of a study designed to test the utility of a visual timeline technique. A key contribution of this article is the application of an alternative technique for researching stress appraisal and coping. The technique conferred a number of benefits that may not have been provided by more conventional approaches, making it a suitable basis for the exploration of stress appraisal and coping. A further contribution is the identification of a straightforward process for analysing the visual data produced

Personal values and involvement in problem behaviors among Bahamian early adolescents: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Few studies, particularly in developing countries, have explored the relationship between adolescents and parental values with adolescent problem behaviors. The objectives of the study are to (1) describe adolescents' personal values, their problem behaviors, and the relationships thereof according to gender and (2) examine the relationship between parental values, adolescent values, and adolescents' problem behaviors among sixth-grade students and one of their parents.</p> <p>Methods</p> <p>The data used in these analyses were from the baseline assessment of a school-based HIV risk reduction intervention being conducted and evaluated among sixth grade students and one of their parents across 9 elementary schools in The Bahamas. Personal values were measured by the Portrait Values Questionnaire (PVQ). Seven reported problem behaviors were queried from the students, which included physical fight with a friend, drank alcohol, beer, or wine, smoked a cigarette, pushed or carried any drugs, carried a gun, knife, screwdriver or cutlass to use as a weapon, had sex and used marijuana or other illicit drugs over the past 6 months. Multilevel modeling for binary data was performed to estimate the associations between adolescent and parental values and adolescent problem behaviors.</p> <p>Results</p> <p>Among 785 students, 47% of the students reported at least one problem behavior. More boys (54%) reported having one or more problem behaviors than girls (41%, p < 0.01). Boys compared to girls expressed a higher level of self-enhancement (means score: 36.5 vs. 35.1; p = 0.03), while girls expressed a higher level of self-transcendence (42.3 vs. 40.7; p = 0.03). The results of multilevel modeling indicates that boys with a higher level of self-enhancement and girls with a higher level of openness to change and a lower level of conservation were more likely to report engagement in problem behaviors. Only two parental values (self-transcendence and conservation) were low or modestly correlated with youth' values (openness to change and self-enhancement). Parental-reported values documented limited association on adolescents' reported values and behaviors.</p> <p>Conclusion</p> <p>In designing interventions for reducing adolescents' problem behaviors, it may be important to understand the values associated with specific problem behaviors. Further exploration regarding lack of association between adolescent and parental values and problem behaviors is needed.</p

The Role of Transporters in the Pharmacokinetics of Orally Administered Drugs

Drug transporters are recognized as key players in the processes of drug absorption, distribution, metabolism, and elimination. The localization of uptake and efflux transporters in organs responsible for drug biotransformation and excretion gives transporter proteins a unique gatekeeper function in controlling drug access to metabolizing enzymes and excretory pathways. This review seeks to discuss the influence intestinal and hepatic drug transporters have on pharmacokinetic parameters, including bioavailability, exposure, clearance, volume of distribution, and half-life, for orally dosed drugs. This review also describes in detail the Biopharmaceutics Drug Disposition Classification System (BDDCS) and explains how many of the effects drug transporters exert on oral drug pharmacokinetic parameters can be predicted by this classification scheme

Analysis of Field Scouting and Insecticide Use

The use of field scouting and insecticide use on Delta cotton farms was investigated. It was found that management and incremental value of scouting increased adoption of scouting. Scouting was not found to be a substitute for insecticide use on these farms. Scouting had a strong effect in increasing the value of the cotton produced

ECONOMIC ANALYSIS OF COTTON INSECT CONTROL IN NORTH CAROLINA

Insect control practices on North Carolina cotton farms in 1976 were investigated as a basis for estimating the costs and returns to a federally sponsored boll weevil eradication program. The mean number of insecticide applications was 10.9, but most were not directed at boll weevils as a primary target. Comparisons on insecticide use, use of field scouting and other practices are compared for two areas of the state, two farm sizes, counties, and those farmers in and not in spray cooperatives. More years of data are needed for a more complete estimate of the advantages of eradication

Conservation tillage, herbicide use, and genetically engineered crops in the United States : the case of soybeans

This study examines the extent to which adopting herbicide-tolerant (HT) soybeans affects conservation tillage practices and herbicide use. The model is estimated using a state-level panel dataset extending across 12 major soybean-producing states from 1996 to 2006. The results of our analysis suggest that HT adoption induces farmers to adopt conservation tillage practices. Our results also show that HT adoption leads to a decrease in quality-adjusted herbicide use