ESTIMATION OF A DEMAND SYSTEM WITH LIMITED DEPENDENT VARIABLES

The study employs the full-information maximum-likelihood method to estimate a censored translog demand system. U.S. household consumption of steak, roast, and ground beef are used to demonstrate the application of the estimation procedure. The proposed methodology produces more efficient estimates than the popular two-step procedures found in demand literature.Demand and Price Analysis,

HOUSEHOLD DEMAND FOR FINFISH: A GENERALIZED DOUBLE-HURDLE MODEL

This study estimates household demand for finfish in the United States using a limited dependent variable model that accounts for both participation and consumption decisions and also accommodates nonnormal heteroskedastic errors. Results suggest that own-price elasticity is near unitary and income elasticity is small. Price of finfish, shopping frequency, Northeast, Black and other non-Whites, and the life-cycle variable “"young, single, no children”" are they key factors that affect significantly both the probability of participation and the level of finfish consumption. Furthermore, a variable may exert opposite effects on the probability and level of consumption.Consumer/Household Economics, Demand and Price Analysis,

CROSS-SECTIONAL ESTIMATION OF U.S. DEMAND FOR BEEF PRODUCTS: A CENSORED SYSTEM APPROACH

Demands for beef products are investigated using the U.S. Department of AgricultureÂ’'s 1987-88 Nationwide Food Consumption Survey data. The censored translog demand system is estimated with full-information and simulated maximum-likelihood procedures. These procedures represent different approaches to evaluation of multiple probability integrals in the likelihood function, but produce very similar parameter and elasticity estimates. Findings suggest sociodemographic variables play important roles in the demand for beef, and that demand for different cuts of beef should be treated differently.Demand and Price Analysis,

AN ECONOMETRIC ANALYSIS OF DONATIONS FOR ENVIRONMENTAL CONSERVATION IN CANADA

As provincial governments in Canada trim budgets, fewer funds are available for environmental conservation programs. Many jurisdictions are letting private interests and/or users of the resource base help fund conservation projects. Thus funding for conservation is becoming more dependent on donations to environmental causes either through direct giving of funds or through memberships in organizations. This study explores some determinants of private contributions to environmental conservation activities through an econometric analysis of donations and memberships relating to wildlife habitat protection and enhancement. We use data from a 1991 survey conducted in the three prairie provinces that provides information on donation behavior, income, wildlife-related activity, household compositions, and a variety of other factors. A double-hurdle econometric model is used to allow independent variables to have different effects on the probability of donations and the level of donations. Our empirical results suggest that changes in the economy will be important to donation behavior. Declines in participation and recruitment in hunting will also have impacts on donations to conservation causes, but these impacts, although significant, may not be as large. However, consumptive and nonconsumptive activities may be influenced by management agencies and used to bolster environmental donations.Environmental Economics and Policy,

Optimization of ultrasound-assisted extraction of bioactive compounds from Gomphrena celosioides Mart. using response surface methodology

In this study, ultrasound-assisted extraction (UAE) was used to extract bioactive compounds from Gomphrena celosioides Mart. Central composite face design (CCF) was used to optimize the influences of extraction factors on total phenolics content (TPC), total flavonoids content (TFC), and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging capacity (DPPH-RSC). The results obtained showed that all factors (solvent to solid ratio, extraction time and extraction temperature) strongly affected TPC, TFC, and DPPH-RSC. The optimal extraction conditions for TPC (3.123 mg GAE/g DW), TFC (1.736 mg QE/g DW), and DPPH-RSC (64.118%) were solvent to solid ratio of 27.3/1 (mL/g), extraction time of 40.2 min, and extraction temperature of 69 oC. In addition, under the optimal conditions, the results pointed out that the experimental values agreed with those predicted. Hence, this model has successfully optimized the extraction conditions for TPC, TFC and DPPH-RSC of Gomphrena celosioides extract.                     KEY WORDS: Antioxidant activity, CCF, Flavonoids, Model, Phenolic compounds, Regression equation   Bull. Chem. Soc. Ethiop. 2020, 34(2), 237-248 DOI: https://dx.doi.org/10.4314/bcse.v34i2.

Fermions in 3D Optical Lattices: Cooling Protocol to Obtain Antiferromagnetism

A major challenge in realizing antiferromagnetic (AF) and superfluid phases in optical lattices is the ability to cool fermions. We determine the equation of state for the 3D repulsive Fermi-Hubbard model as a function of the chemical potential, temperature and repulsion using unbiased determinantal quantum Monte Carlo methods, and we then use the local density approximation to model a harmonic trap. We show that increasing repulsion leads to cooling, but only in a trap, due to the redistribution of entropy from the center to the metallic wings. Thus, even when the average entropy per particle is larger than that required for antiferromagnetism in the homogeneous system, the trap enables the formation of an AF Mott phase.Comment: 4 pages; 5 figures; also see supplementary material in 2 pages with 1 figur

Factors Influencing Consumer Likelihood of Purchasing a Flexible-Fuel or Hybrid Automobile

Developing fuels and vehicles that reduce our reliance on fossil fuels has become a priority due to the threat of global climate change and desire for reduced dependence on oil imports. Flexible-fuel vehicles that can run on ethanol/gasoline blends of up to 85% ethanol and hybrid electric vehicles present two such opportunities. While production of both flexible-fuel and hybrid vehicles is increasing, there is still a great deal of uncertainty about how consumers will respond to these products. To address this uncertainty, data was collected through an online survey of automobile owners that asked respondents how likely they were to choose either a flexible-fuel or hybrid vehicle as their next vehicle. A bivariate probit model was used to jointly analyze responses to these two questions. The results show that, while there was some overlap in the factors correlated with perceived likelihood of choosing one of these two types of automobiles, there were also clear differences. These results should benefit policymakers, marketers and academics seeking a better understanding of the respective markets for these vehicles.flexible-fuel vehicles, ethanol, E85, hybrid electric vehicles, Demand and Price Analysis, Environmental Economics and Policy, Resource /Energy Economics and Policy,

Factors Influencing Willingness-to-Pay for the Energy Star Label

In the United States, nearly 17 percent of greenhouse gas emissions come from residential energy use. Increases in energy efficiency for the residential sector can generate significant energy savings and emissions reductions. Consumer labels, such as USEPA’s Energy Star, promote conservation by providing consumers with information on energy usage for household appliances. This study examines how the Energy Star label affects consumer preferences for refrigerators. An online survey of a national sample of adults suggest that consumers are, on average, willing to pay an extra $249.82 to$349.30 for a refrigerator that has been awarded the Energy Star label. Furthermore, the results provide evidence that willingness to pay was motivated by both private (energy cost savings) and public (environmental) benefits.Energy Star, willingness-to-pay, eco-label, Consumer/Household Economics, Demand and Price Analysis, Environmental Economics and Policy,