15,064 research outputs found
Exact solution of Riemann--Hilbert problem for a correlation function of the XY spin chain
A correlation function of the XY spin chain is studied at zero temperature.
This is called the Emptiness Formation Probability (EFP) and is expressed by
the Fredholm determinant in the thermodynamic limit. We formulate the
associated Riemann--Hilbert problem and solve it exactly. The EFP is shown to
decay in Gaussian.Comment: 7 pages, to be published in J. Phys. Soc. Jp
Competing Quantum Orderings in Cuprate Superconductors: A Minimal Model
We present a minimal model for cuprate superconductors. At the unrestricted
mean-field level, the model produces homogeneous superconductivity at large
doping, striped superconductivity in the underdoped regime and various
antiferromagnetic phases at low doping and for high temperatures. On the
underdoped side, the superconductor is intrinsically inhomogeneous and global
phase coherence is achieved through Josephson-like coupling of the
superconducting stripes. The model is applied to calculate experimentally
measurable ARPES spectra.Comment: 5 pages, 4 eps included figure
The development and evaluation of a job aid for lesson planning for volunteer teachers
A number of institutions, including community organizations, scouting programs, churches, and even businesses, rely on volunteer teachers to staff educational programs. The volunteer teachers are provided curriculum materials to use, but often do not receive training to sufficiently equip them for the task of teaching. A job aid might provide performance support for one aspect of their teaching responsibilities, the task of planning for teaching. The prupose of this study is to chronicle the development process for the creation of a job aid for planning for teaching (based on a simplified version of Gagné’s Nine Events of Instruction) and to evaluate whether the job aid will facilitate a volunteer teacher’s ability to plan for teaching. A developmental methodology is used to chronicle the development process. An experimental design methodology is applied to evaluate the effectiveness of the job aid on a volunteer teacher’s ability to plan for teaching. The sample population is selected from ten churches within southeast Michigan that use volunteers to staff religious education programs and includes 43 participants teaching during the first three months of 1998. An analysis is conducted to determine differences in lesson plans created by the control group and the treatment group using the planning job aid. Additional information is gathered from the treatment group on opinions about the use of the job aid. The job aid, used in conjunction with published curriculum materials, appears to be sufficient to guide volunteer teachers through a planning process, producing better quality lesson plans than the control group did without the intervention treatment. Formal training, years of experience, age group taught, use of denominational or nondenominational curriculum materials seem to have no effect on the results of the use of the job aid. The data suggest that the job aid is sufficient as a stand-alone intervention. Additional instruction does not appear to be necessary to prepare volunteer teachers to use the job aid. Findings suggest that the job aid enhances the teaching experience, helping the majority of the volunteer teachers in the treatment group to feel more confident
Stabilization of Existing Sheet Pile Cell in the Ohio River
An existing 40 foot diameter sheet pile cell (cell) was used to support a dry fly ash loading platform at an electrical power generating facility on the Ohio River. The cell was designed and constructed in 1986 for support of a coal barge unloading crane but was never put into service. The cell has leaned riverward several inches in the years after construction. Stability analysis indicated a less than adequate overturning factor of safety without any additional loads. The addition of the loading platform could result in an overturning failure. A stabilizing system which provided a horizontal stabilizing force of 750,000 lbs. was developed, designed and subsequently installed. The system included a tension belt steel channel bent about the cell circumference connected to two-1Âľinch diameter high strength tension bars at each end. The tension bars extended 100 feet landward and were anchored to two pile caps. The pile caps were supported on a tripod of three-120 ton working load HP14x117 piles driven on a 4:1 batter. The horizontal stabilizing force for the cell originates from four-200 foot long rock anchors (20 foot long bonded length) installed in each pile cap at a nominal angle of 45- degrees from the horizontal. The tension belt channel elongated 3 inches during anchor proof testing while the strand anchors elongated approximately 18 inches. It was necessary to test the anchors in pairs to maintain a balanced loading condition on the tension belt channel, requiring adjusting and balancing the load in the anchors and tension bars continuously to maintain the pile caps in a neutral position. Each anchor proof-test required six hydraulic cylinders and four power packs operated simultaneously at different pressures. After each pair of anchors was proof-tested, the anchors were de-stressed until all pairs had been proof-tested. Then the anchors were reloaded in pairs and locked off at 50% of the 120 ton design load
North Dakota Republicans and the Revolt of the Farmers, 1889
This thesis responds to Professor Howard R. Lamar\u27s assertion that farmers dominated the last territorial legislature, the North Dakota constitutional convention, and the first administration of the state of North Dakota. A closer dating of the stage in the development of Populism in North Dakota at which the farmers in state politics developed a united, conscious movement to achieve Populist goals is needed.
An analysis of new sources suggests different conclusions from those implied by Professor Lamar in his book Dakota Territory 1861-1889 A Study of Frontier Politics. First, the farmers as a class did not form a united faction in the last territorial legislature, nor the constitutional convention, against their opponents representing the oligarchy and the railroad interests. Secondly, the farmers did not dominate the North Dakota constitutional convention of 1889. The farmer politicians did coalesce into a united group against the political machine during the first Republican state convention in August, 1889. The major factor in that coalescence, however, appeared to be opposition to the machine and not Populist ideology. Consequently, Populist political action occurred at the state level of government after the summer of 1890
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