12,632 research outputs found
ENERGY REQUIREMENTS IN FOOD MARKETING
Energy needs of the various sectors of the food industry are outlined. Also, potential problems in meeting these needs are discussed.Resource /Energy Economics and Policy,
Constraints to the Growth of Native American Gaming
Since the Indian Gaming Regulatory Act was passed in 1988, high-stakes bingo halls and casino operations have spread to reservations across the country and generated millions of dollars in revenues for their respective tribes. While some tribes have been able to exploit their sovereign status and establish high-stakes bingo parlors and casinos on reservations across the country, this study describes how external and internal constraints limit the adoption of gaming ventures by other tribes. Constraints include the location of the reservations, increasing competition, disagreements among tribal members, and opposition from the private and public sectors
Macroeconomic implications of changes in micro volatility
We review evidence on the Great Moderation in conjunction with evidence about volatility trends at the micro level. We combine the two types of evidence to develop a tentative story for important components of the aggregate volatility decline and its consequences. The key ingredients of the story are declines in firm-level volatility and aggregate volatility â most dramatically in the durable goods sector â but the absence of a decline in the volatility of household consumption and individual earnings. Our explanation for volatility reduction stresses improved supply chain management, particularly in the durable goods sector, and a shift in production and employment from goods to services. We also provide some evidence for a specific mechanism, namely shorter lead times for materials orders. The tentative conclusion we draw is that, although better supply chain management involves potentially large efficiency gains with first-order effects on welfare, it does not imply (nor is there much evidence for) a reduction in uncertainty faced by individuals.
Partial Difference Sets in \u3ci\u3ep\u3c/i\u3e-groups
Most of the examples of PDS have come in p-groups, and most of these examples are in elementary abelian p-groups. In this paper, we will show an exponent bound for PDS with the same parameters as the elementary abelian case
Almost Difference Sets and Reversible Divisible Difference Sets
Let G be a group of order mn and N a subgroup of G of order n. If D is a k-subset of G, then D is called a (m, n, k, λ1, λ2) divisible difference set (DDS) provided that the differences dd\u27-1 for d, d\u27 â D, d â d\u27 contain every nonidentity element of N exactly λ1 times and every element of G - N exactly λ2 times. Difference sets are used to generate designs, as described by [4] and [9]. D will be called an Almost Difference set (ADS) if λ1 and λ2 differ by 1. The reason why these are interesting involves their relationship to symmetric difference sets. A symmetric difference set is a DDS with λ1 = λ2, so the ADS are almost difference sets. Symmetric difference sets are becoming more and more difficult to construct, and this is as close as we can get with a divisible difference set
Construction of Relative Difference Sets in p-groups
Jungnickel (1982) and Elliot and Butson (1966) have shown that (pj+1,p,pj+1,pj) relative difference sets exist in the elementary abelian p-group case (p an odd prime) and many 2-groups for the case p = 2. This paper provides two new constructions of relative difference sets with these parameters; the first handles any p-group (including non-abelian) with a special subgroup if j is odd, and any 2-group with that subgroup if j is even. The second construction shows that if j is odd, every abelian group of order pj+2 and exponent less than or equal to p(j+3)/2 has a relative difference set. If j is even, we show that every abelian group of order 2j+2 and exponent less than or equal to 2(j+4)/2 has a relative difference set except the elementary abelian group. Finally, Jungnickel (1982) found (pi+j,pi,pi+j,pj) relative difference sets for all i, j in elementary abelian groups when pis an odd prime and in i4Ăj2 when p = 2. This paper also provides a construction for i+j even and iâ©œj in many group with a special subgroup. This is a generalization of the construction found in a submitted paper
Difference Sets in Abelian 2-Groups
Examples of difference sets are given for large classes of abelian groups of order 22d + 2. This fills in the gap of knowledge between Turyn\u27s exponent condition and Dillon\u27s rank condition. Specifically, it is shown thatâ€/(2d)Ăâ€/(2d+2) andâ€/(2d+1)ĂZ/(2d+1) both admit difference sets, and these have many implications
A Note on Nonabelian (64, 28, 12) Difference Sets
The existence of difference sets in abelian 2-groups is a recently settled problem [5]; this note extends the abelian constructs of difference sets to nonabelian groups of order 64
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