Free energy of the three-state τ2(tq)\tau_2(t_q) model as a product of elliptic functions

{We show that the free energy of the three-state $\tau_2(t_q)$ model can be expressed as products of Jacobi elliptic functions, the arguments being those of an hyperelliptic parametrization of the associated chiral Potts model. This is the first application of such a parametrization to the $N$-state chiral Potts free energy problem for $N > 2$.Comment: 20 pages, 3 figure

Sound Computational Interpretation of Formal Encryption with Composed Keys

The formal and computational views of cryptography have been related by the seminal work of Abadi and Rogaway. In their work, a formal treatment of encryption that uses atomic keys is justified in the computational world. However, many proposed formal approaches allow the use of composed keys, where any arbitrary expression can be used as encryption key. We consider an extension of the formal model presented by Abadi and Rogaway, in which it is allowed to use composed keys in formal encryption. We then provide a computational interpretation for expressions that allow us to establish the computational soundness of formal encryption with composed keys

Algebraic reduction of the Ising model

We consider the Ising model on a cylindrical lattice of L columns, with fixed-spin boundary conditions on the top and bottom rows. The spontaneous magnetization can be written in terms of partition functions on this lattice. We show how we can use the Clifford algebra of Kaufman to write these partition functions in terms of L by L determinants, and then further reduce them to m by m determinants, where m is approximately L/2. In this form the results can be compared with those of the Ising case of the superintegrable chiral Potts model. They point to a way of calculating the spontaneous magnetization of that more general model algebraically.Comment: 25 pages, one figure, last reference completed. Various typos fixed. Changes on 12 July 2008: Fig 1, 0 to +1; before (2.1), if to is; after (4.6), from to form; before (4.46), first three to middle two; before (4.46), last to others; Conclusions, 2nd para, insert how ; renewcommand \i to be \rm

Two-Stream Instability Model With Electrons Trapped in Quadrupoles

We formulate the theory of the two-stream instability (e-cloud instability) with electrons trapped in quadrupole magnets. We show that a linear instability theory can be sensibly formulated and analyzed. The growth rates are considerably smaller than the linear growth rates for the two-stream instability in drift spaces and are close to those actually observed

Information Technology as Coordination Infrastructure

Business information technology is traditionally viewed as information provision technology. In this view, organizations use their IT to implement databases that provide people with information when they want it. This view is persistent even though information provision is never an end in itself but always has the further purpose to support the coordination of activities of people. The role if IT as coordination technology became more prominent in the 1980s with the advent of network technology, that allowed activities across different businesses to be coordinated. This trend has accellerated since the growth of Internet usage, and today IT is used to support an increasingly varied range of processes performed by a variety of partners that do not all have a hierarchical relation to each other. This makes it difficult to analyze requirements for IT support and specify IT solutions: Business processes may not be well-defined, and interests of different businesses may clash. This report argues that to deal with this in requirements engineering and IT solution specification, business information technology should not be viewed as IT support for business processes but as IT support for the coordination of activities in one or more businesses. We will identify three basic coordination mechanisms, namely coordination by price, by management, and by shared norms, and for each of these mechanisms, we will identify requirements for IT support. The advent of flexible and standardized networking technology has facilitated the creation of novel coordination mechanisms within these three general paradigms, and we will give an inventory of generalized coordination mechanisms made possible by current IT. Finally, we will draw conclusions for requirements engineering methods for IT support for each of the coordination mechanisms identified by the framework

Procedure for estimating tourism benefits

Mineral Industry Research laboratory Report No. 29, "Optimum Transportation Systems to Serve the Mineral Industry North of the Yukon Basin in Alaska", considers the transportation needs of the area north of the Yukon. The only industries that can be established there within the foreseeable future are minerals production, recreation, reindeer husbandry, and trapping. The present paper, M.I. R. L. Report No. 29A was originally written as an appendix to Report No. 29. After some consideration, if was decided that al though it is. too detai Ied an analysis of tourism tobe included in M.I.R.L. Report No. 29, it also is too valuable a contribution to not be published at all. Therefore, it has been published in its present form as a separate report. It is recommended that M. I. R. L. Report No. 29 be consulted, especially Chapter 6

Mass movement in Tangoio conservation reserve northern Hawkes Bay

In a random sample of 52 valley-side profiles at Tangoio, mass movements are shown to occur preferentially on profiles with a northerly aspect, which are long, or steeply sloping. Detailed measurements of 27 debris slide and two slump scars dating from a storm in May 1971 enable an estimate of the rate of erosion of loess and volcanic ash from valley-sides to be made. Valley-side slopes are changing from a convexo-concave equilibrium form under the original forest towards a new, more rectilinear equilibrium form under grass

Lauchlin Currie (1902-1993)

Biography of the economist Lauchlin Currie. At Harvard in the early 1930s Currie pioneered a monetary diagnosis of the 1929-32 collapse and placed blame on the Federal Reserve Board. As a prominent New Dealer at the Fed during 1934-9 he urged contra-cyclical monetary and fiscal activism. During 1939-45 he worked in Washington as President Roosevelt's economic adviser. After heading a World Bank mission to Colombia in 1949 he spent 40 years advising on national development there. He emphasized urban housing as a leading sector, based on an innovative housing finance system, and extended Allyn Young's ideas on macroeconomic increasing returns and endogenous growth

The synthesis and some properties of nylon 4,T

The synthesis of nylon 4,T from tetramethylenediamine and a terephthalic acid derivative was studied in a two step-process: prepolymerization, followed by postcondensation in the solid state (4 h, 290°C). The prepolymers were prepared by the nylon salt method, ester polymerization method, interfacial method, and a low temperature solution method. A maximum ηinh of 1.52 was obtained. From a solution in trifluoroacetic acid, films were cast and on these films we studied its IR spectrum, WAXS, and melting behavior with DSC. A boiled up sample had a double melting transition at 434 and 475°C and a ΔH0 of 130 J/g