3,091 research outputs found
Measuring Part-Whole Bias: Some Evidence from Crop Biotechnology
We analyze the non-pecuniary aspects of some crop biotechnologies taken from three farm-level surveys. We focus particularly on the phenomen on of part-whole bias, which is the empirical finding that the sum of the stated part-worths (the value of each nonpecuniary characteristic) is greater than the stated total value of all the non-pecuniary characteristics. We analyze the empirical evidence of part-whole bias in the surveys, while decomposing it to further understand the phenomenon and to rescale the stated values of the non-pecuniary characteristics in the surveys. We find for all three surveys that the degree to which part-worths should be rescaled is about 60 percent.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,
Relative Importance of Environmental Attributes Using Logistic Regression
We investigate the problem of determining the relative importance of attributes in the discrete choice setting. Four alternative methods of extracting the relative importance of attributes are considered. The empirical application involves the development of a risk index system for individual herbicides combining the information on the herbicides' different human and environmental risks. The values of the pesticide risk indices are found to be consistent across the different methods.Environmental Economics and Policy,
Video Game Interventions to Improve Cognition in Older Adults
Cognitive abilities decline as part of the normal aging process. Various non-pharmacological interventions are being studied in an effort to ameliorate this cognitive decline. Some of these interventions include computerized cognitive training, such as neuropsychological software (i.e., brain training games) and video games. A previous study in our lab found that older adults who played a brain training game or a video poker game showed similar cognitive gains. The purpose of the present study was to follow the methodological procedures of our previous study to try and determine if the positive effects seen for the brain training program and video poker were due to training effects or merely engagement effects. In doing so, it also sought to determine if a visual art intervention, a relatively unstudied but potentially beneficial intervention, would elicit cognitive gains. Twenty-five individuals (Mage = 86, Meducation = 16.2) were quasi-randomly assigned to an experimental digital art intervention, Art Academy, or an active control condition, Tetris. Participants played their assigned game at least twenty minutes per day for six weeks. Comprehensive neuropsychological assessments were administered before and after the intervention. Outcome measures were in the form of residualized change scores were calculated by regressing the pre-test scores onto the post-test scores to reduce effects of baseline and other non-treatment factors. Compared to the Tetris group, the digital art group improved on aspects of a list-learning test, visual memory test, a scanning and sequencing task, a psychomotor task, a mental rotation task, and a composite score of all cognitive change (Total Change Score). The Tetris group improved on a math fluency task, and both groups improved on the delayed recall of a story memory task. However, the Art Academy group also engaged in the intervention for significantly more minutes of overall play time than the Tetris group, potentially confounding the results. Two groups were created via a median split based on the duration of gameplay: High Gameplay and Low Gameplay. The High Gameplay group showed greater improvement on visual memory, verbal memory, a measure of executive functioning, as well as the Total Change Score. Compared to the active control of the current study (Tetris), the Brain Age group of the previous study showed greater improvement on tasks that are specifically trained (i.e., visual working memory, math fluency) but not untrained tasks (e.g., verbal memory). The study suggests that playing a digital art video game could be a viable intervention to improve cognitive functioning in older adults. However, future research is also needed because the confounding of total gameplay time with group, a metric that other studies rarely report, precludes strong conclusions about the specific training effects
On the Economics of Crop Rotations to Inhibit Corn Rootworm Resistance Development
Corn rootworm resistance to one of the corn rootworm traits has been found in a few isolated places in the Corn Belt. Several crop rotations have been proposed by industry officials and academics to attempt to eliminate or delay this resistance. Three of these rotation schemes are evaluated in this article as to their relative monetary returns, as well as other, non-monetary attributes of the rotations
Gold(I)-Catalyzed Reactivity of Furan-ynes with N-Oxides: Synthesis of Substituted Dihydropyridinones and Pyranones
[Image: see text] The reactivity of “furan-ynes” in combination with pyridine and quinoline N-oxides in the presence of a Au(I) catalyst, has been studied, enabling the synthesis of three different heterocyclic scaffolds. Selective access to two out of the three possible products, a dihydropyridinone and a furan enone, has been achieved through the fine-tuning of the reaction conditions. The reactions proceed smoothly at room temperature and open-air, and were further extended to a broad substrate scope, thus affording functionalized dihydropyridinones and pyranones
Cusp Catastrophe Models for Cognitive Workload and Fatigue in Teams
The use of two cusp catastrophe models has been effective for untangling the effects of cognitive workload, fatigue, and other complications on the performance of individuals. This study is the first to use the two models to separate workload and fatigue effects on team performance. In an experiment involving an emergency response simulation, 360 undergraduates were organized into 44 teams. Workload was varied by team size, number of opponents, and time pressure. The cusp models for workload and fatigue were more accurate for describing trends in team performance criteria compared to linear alternatives. Individual differences in elasticity-rigidity were less important than subjective workload and experimental conditions as control variables. Fluid intelligence within the team was an important compensatory ability in the fatigue model. Results further supported the nonlinear paradigm for the assessment of cognitive workload and fatigue and demonstrated its effectiveness for understanding team phenomena
Fast and Sensitive Detection of Soil-Borne Cereal Mosaic Virus in Leaf Crude Extract of Durum Wheat
Soil-borne cereal mosaic virus (SBCMV) is a furovirus with rigid rod-shaped particles containing an ssRNA genome, transmitted by Polymyxa graminis Led., a plasmodiophorid that can persist in soil for up to 20 years. SBCMV was reported on common and durum wheat and it can cause yield losses of up to 70%. Detection protocols currently available are costly and time-consuming (real-time PCR) or have limited sensitivity (ELISA). To facilitate an efficient investigation of the real dispersal of SBCMV, it is necessary to develop a new detection tool with the following characteristics: no extraction steps, very fast results, and high sensitivity to allow pooling of a large number of samples. In the present work, we have developed a reverse transcription loop-mediated isothermal amplification (RT-LAMP) protocol with such characteristics, and we have compared it with real-time PCR. Our results show that the sensitivity of LAMP and real-time PCR on cDNA and RT-LAMP on crude extracts are comparable, with the obvious advantage that RT-LAMP produces results in minutes rather than hours. This paves the way for extensive field surveys, leading to a better knowledge of the impact of this virus on wheat health and yield
Droplet minimizers for the Gates-Lebowitz-Penrose free energy functional
We study the structure of the constrained minimizers of the
Gates-Lebowitz-Penrose free-energy functional ,
non-local functional of a density field , , a
-dimensional torus of side length . At low temperatures, is not convex, and has two distinct global minimizers,
corresponding to two equilibrium states. Here we constrain the average density
L^{-d}\int_{{\cal T}_L}m(x)\dd x to be a fixed value between the
densities in the two equilibrium states, but close to the low density
equilibrium value. In this case, a "droplet" of the high density phase may or
may not form in a background of the low density phase, depending on the values
and . We determine the critical density for droplet formation, and the
nature of the droplet, as a function of and . The relation between the
free energy and the large deviations functional for a particle model with
long-range Kac potentials, proven in some cases, and expected to be true in
general, then provides information on the structure of typical microscopic
configurations of the Gibbs measure when the range of the Kac potential is
large enough
Regression spline bivariate probit models: A practical approach to testing for exogeneity
Bivariate probit models can deal with a problem usually known as endogeneity. This issue is likely to arise in observational studies when confounders are unobserved. We are concerned with testing the hypothesis of exogeneity (or absence of endogeneity) when using regression spline recursive and sample selection bivariate probit models. Likelihood ratio and gradient tests are discussed in this context and their empirical properties investigated and compared with those of the Lagrange multiplier and Wald tests through a Monte Carlo study. The tests are illustrated using two datasets in which the hypothesis of exogeneity needs to be tested
Real Estate Asset Management Companies’ Economies of Scale: Is It a Dream or Reality? The Italian Case
The research focuses on a sample of 26 Italian real estate asset management companies (Società di Gestione del Risparmio “SGR”)—whose asset management is totally linked to real estate funds—that considers a period of six years (2013–2018). Using some variables extrapolated from the internal accountability of each SGR, the analysis investigates possible relationships between them to verify the presence or absence of economies of scale of Italian real estate management companies by multivariate regressions. The results show that there is no single model for profit maximization and cost minimization, but all depends on the business model that each SGR decides to adopt
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