Pigeons' demand and preference for specific and generalized tokens was examined in a token economy. Pigeons could produce and exchange different colored tokens for food, for water, or for food or water. Token production was measured across three phases, which examined: (1) across-session price increases (typical demand curve method); (2) within-session price increases (progressive-ratio, PR, sc...

This paper emphasizes the benefits of an agricultural strategy of development in developing countries. It begins by analyzing the close links between food and employment in the development process. In an underdeveloped country, food production is minimal, but demand is as well because of the small population growth. After development begins, income rises and food demand outstrips production....

Nutrition -The problem of nutrition in these young infants is made doubly difficult by a great demand for food and a poor supply. The demand for food is relatively great because of the increased heat loss of premature infants. In proportion to its bulk the little body has a large surface from which to radiate heat. In addition, the layer of non-conducting fat is thin and the heat regulating mec...

Zooplankton feeding activity is hypothesized to attenuate the downward flux of elements in the ocean. We investigated whether the zooplankton community composition could influence the flux attenuation, due to the differences of feeding modes (feeding on dispersed vs. aggregated particles) and of metabolic rates. We fed 5 copepod species-three calanoid, one harpacticoid and one poecilamastoid-mi...

The sufficient supply of food and energy requires large amounts of fresh water. Mainly required for irrigation, but also processing and cooling purposes, water is one of the essential resources in both sectors. Rising global population numbers and economic development could likely cause an increase in natural resource demand over the coming decades, while at the same time climate change might l...

The impact of consumer demand for quality on the agricultural and food system is an increased emphasis on quality differentiation but not all in the direction of upgrading quality. The more elite market segments are thriving and reaching growing numbers of consumers but the basic price/quality markets remain strong. Most recent economic studies find that consumers are willing to pay for food sa...

Characterization and evaluation of a biological submerged filter was carried out on a full-scale pilot plant performing removal of biochemical oxygen demand (BOD) and total nitrogen (TN) from pre-treated urban wastewater. The average influent values of BOD5, chemical oxygen demand (COD) and TN were 370, 1,015 and 60 mg/L, respectively. The pilot plant produced good discharge quality during stea...

The purpose of the present study was to investigate the effect of the travel distance of tourists on the demand for domestic tourism in Mashhad. Data used in this research was cross-sectional which includes 1388 domestic tourist families who stayed for at least one night in Mashhad City in 2005. The sample was selected using a randomized stratified sampling method and the data was gathered by a...