2,962 research outputs found
Lewis through a looking glass : public sector employment, rent-seeking, and economic growth
This paper argues that the labor transfer process outlined by the Lewis model (1954) can give rise to surplus labour - in the sense than the marginal product of labour is less that the wage - in the public part of the modern sector and that this may deprive the modern sector of its dynamism. Moreover, creating sheltered employment tends to be self-perpetuating. It creates and consolidates vested interests that seek to perpetuate the protected jobs. In the inverse of the Lewis model, the extent of surplus labour increases, rather than diminishes, over time.Environmental Economics&Policies,Banks&Banking Reform,Economic Theory&Research,Public Sector Economics&Finance,Health Monitoring&Evaluation
Combining mutualistic yeast and pathogenic virus - a novel method for codling moth control
The combination of a pathogenic virus and mutualistic yeasts isolated from larvae of codling moth Cydia pomonella is proposed as a novel insect control technique. Apples were treated with codling moth granulovirus (CpGV) and either one of three yeasts, Metschnikowia pulcherrima, Cryptococcus tephrensis, or Aureobasidium pullulans. The combination of yeasts with CpGV significantly increased mortality of neonate codling moth larvae, compared with CpGV alone. The three yeasts were equally efficient in enhancing the activity of CpGV. The addition of brown cane sugar to yeast further increased larval mortality and the protection of fruit against larvae. In comparison, without yeast, the addition of sugar to CpGV did not produce a significant effect. A field trial confirmed that fruit injury and larval survival were significantly reduced when apple trees were sprayed with CpGV, M. pulcherrima, and sugar. We have shown earlier that mutualistic yeasts are an essential part of codling moth larval diet. The finding that yeast also enhances larval ingestion of an insect-pathogenic virus is an opportunity for the development of a novel plant protection technique. We expect the combination of yeasts and insect pathogens to essentially contribute to future insect management
How Agricultural Economists Increase the Value of Agribusiness Research
Historically, there has been declining cooperation between agribusiness firms and agricultural economists. In new product marketing research, firms' tend to conduct their own analyses, partially due to confidentiality, usually consisting of simple univariate or bivariate statistics such as chi-squared tests of independence. The primary objective of this paper is to demonstrate, through a case study, one way in which agricultural economists can add value to agribusiness firms research. Results from the econometric model offer a richer explanation of consumer behavior and may be more useful to agribusiness firms.Teaching/Communication/Extension/Profession,
Crop Revenue and Yield Insurance Demand: A Subjective Probability Approach
A multinomial logit is utilized to model the choice of whether to purchase yield or revenue insurance using subjectively elicited survey data. Our results indicate that the demand for crop insurance is inelastic (-0.40), consistent with most earlier yield elasticity estimates, but the elasticity for choices between yield and revenue insurance is found to be relatively more elastic (-0.88).crop insurance, elasticities, multinomial logit model, revenue demand, subjective elicitation, survey, Agribusiness, Crop Production/Industries, Demand and Price Analysis, Q18,
Target Markets for Grain and Cotton Marketing Consultants and Market Information Systems
This paper examines the use of market consultants and market information systems by grain and cotton producers. A model of producer demand for marketing information and consultants is proposed that decomposes price received into exogenous and endogenous components. The analysis is based on a survey of over 1,600 producers. The results suggest that expenditures on market information systems and market consultants are not independent and, more specifically, expenditures on marketing consultants substitute for expenditures on market information systems.expected utility, market information, marketing, risk, Tobit, Marketing,
Modelling granular soil to predict pressures on integral bridge abutments
Presented here is a granular soil model created to investigate the soil pressures which develop behind integral bridge abutments. The problem is introduced along with a brief summary of the fundamental behaviour, the model produced, and the initial validation. The paper looks at the initial outcome of the final validation procedure where experimental behaviour of an abutment is compared to the modelled behaviour, and the influence of the Young's modulus profile applied is investigated. The results show that the model behaves as expected producing lateral stresses close to those measured experimentally. Comparisons show that the Young's modulus profile adopted influences the resultant lateral stresses sufficiently to warrant further investigation
Enhanced Characterization of Drug Metabolism and the Influence of the Intestinal Microbiome: A Pharmacokinetic, Microbiome, and Untargeted Metabolomics Study.
Determining factors that contribute to interindividual and intra-individual variability in pharmacokinetics (PKs) and drug metabolism is essential for the optimal use of drugs in humans. Intestinal microbes are important contributors to variability; however, such gut microbe-drug interactions and the clinical significance of these interactions are still being elucidated. Traditional PKs can be complemented by untargeted mass spectrometry coupled with molecular networking to study the intricacies of drug metabolism. To show the utility of molecular networking on metabolism we investigated the impact of a 7-day course of cefprozil on cytochrome P450 (CYP) activity using a modified Cooperstown cocktail and assessed plasma, urine, and fecal data by targeted and untargeted metabolomics and molecular networking in healthy volunteers. This prospective study revealed that cefprozil decreased the activities of CYP1A2, CYP2C19, and CYP3A, decreased alpha diversity and increased interindividual microbiome variability. We further demonstrate a relationship between the loss of microbiome alpha diversity caused by cefprozil and increased drug and metabolite formation in fecal samples. Untargeted metabolomics/molecular networking revealed several omeprazole metabolites that we hypothesize may be metabolized by both CYP2C19 and bacteria from the gut microbiome. Our observations are consistent with the hypothesis that factors that perturb the gut microbiome, such as antibiotics, alter drug metabolism and ultimately drug efficacy and toxicity but that these effects are most strongly revealed on a per individual basis
Integral bridges? Development of a constitutive soil model for soil structure interaction
Traditionally, engineers have used bearings and expansion joints to accommodate bridge expansion and contraction caused by daily and seasonal temperature fluctuations. Studies carried out in the late 1980s showed durability problems can be associated with bearings and expansion joints Wallbank, 1989. Since the mid twentieth century Integral Bridges with no expansion joints or bearings have been used. Deck expansion and contraction is accommodated by movement of the abutments into the retained fill. This eliminates the problem of durability but the movement of the abutments has been thought to cause a build up of horizontal pressures, particularly in the case of full height abutments. In the United Kingdom BA42/96 Highways Agency, 2000 was issued and gave guidance on the soil pressures that should be adopted in design. The validity of the work on which the code of practice was based is a subject of continued debate by both researchers and practicing engineers. For this reason Integral Bridges have been used much less widely than conventional bridges. As part of a strategy by the University of Southampton to further investigate the occuring soil pressures, Xu 2005 carried out radial controlled triaxial tests of granular material under cyclic loading. The applied strain and stress path used represented that typically experienced by an element of retained material behind an integral bridge abutment. This was the first time that the fundamental behaviour had been investigated in this way. The further research discussed in this paper builds upon this by use of numerical modelling. The fundamental behaviour of granular material under this particular loading could not be represented by any available constitutive model and therefore a new model was be developed based on this behaviour. The basis of the model and initial validation process are discussed. The first stage of the validation process was implementation in a commercially available spreadsheet package. This was then used to develop a model in the Finite Difference Method package FLAC. Once this was implemented, the triaxial tests were modelled and the results compared to experimental data
THE ECONOMIC FACTORS INFLUENCING PRODUCERS' DEMAND FOR FARM MANAGERS
Results from a Tobit model showed a complementary relationship between marketing inputs and the decision to hire farm managers. According to the results, as farmers increase expenditure on marketing consultants and information systems, their expenditure on farm managers increase as well.Farm Management,
Recommended from our members
Benchmarking urine storage and collection conditions for evaluating the female urinary microbiome.
Standardized conditions for collection, preservation and storage of urine for microbiome research have not been established. We aimed to identify the effects of the use of preservative AssayAssure® (AA), and the effects of storage time and temperatures on reproducibility of urine microbiome results. We sequenced the V3-4 segment of the 16S rRNA gene to characterize the bacterial community in the urine of a cohort of women. Each woman provided a single voided urine sample, which was divided into aliquots and stored with and without AA, at three different temperatures (room temperature [RT], 4 °C, or -20 °C), and for various time periods up to 4 days. There were significant microbiome differences in urine specimens stored with and without AA at all temperatures, but the most significant differences were observed in alpha diversity (estimated number of taxa) at RT. Specimens preserved at 4 °C and -20 °C for up to 4 days with or without AA had no significant alpha diversity differences. However, significant alpha diversity differences were observed in samples stored without AA at RT. Generally, there was greater microbiome preservation with AA than without AA at all time points and temperatures, although not all results were statistically significant. Addition of AA preservative, shorter storage times, and colder temperatures are most favorable for urinary microbiome reproducibility
- …
