The Majumdar-Ghosh chain. Twofold ground state and elementary excitations

Recently it was proved that the Majumdar-Ghosh chain with the Hamiltonian H=4 Sigma j=12NSj.Sj+1+2 Sigma j=12N Sj.Sj+2, Si+2N identical to Si, Si=1/2, has at least two ground states, in which the spins are arranged in nearest-neighbour singlet pairs. In this work it is shown that these two states are the only ground states. Besides, a rapidly converging variational method is given to determine the elementary excitation

HEDGING RISK FOR FEEDER CATTLE WITH A TRADITIONAL HEDGE COMPARED TO A RATIO HEDGE

This paper compares hedging risk for various weights of feeder cattle hedged with a traditional cross hedge and a ratio cross hedge. A traditional hedge calls for the purchase/sale of one pound of futures for each pound of cash feeder cattle. By contrast, a ratio hedge requires estimation of a hedge ratio to determine the number of pounds of futures needed to hedge one pound of cash feeder cattle. Hedge ratios were found to be larger than 1.0 for light-weight feeder cattle. By using the estimated hedge ratios, it was shown that hedging risk could be reduced 20-50 percent compared to that achieved by using a hedge ratio of 1.0.Livestock Production/Industries,

The Cotton Wizard: A Software Implementation of a Cotton Variety Selection Model

The Cotton Wizard is an implementation of a cotton variety selection model intended to assist decision-makers (including producers, farm managers, extension specialists, and breeders) in variety selection. The program uses objective cotton performance test data available from state agricultural experiment stations. The decision criteria for variety selection are based on expected economic return (mean net revenue) of a variety and the variability of returns (coefficient of variation). Total revenue is calculated from lint price and seed price, and lint and seed yields. Lint and seed prices are determined by their respective quality characteristics. Adjustments are made for costs that may differ among varieties, such as planting seed cost (seed and technology costs), harvest and ginning costs, and herbicide and insecticide costs in comparisons of transgenic and conventional varieties. Users are provided with information on varieties—such as mean net revenue (total revenue less costs), variability in net revenue, and agronomic characteristics—to aid in the decision process. The Cotton Wizard is available as a Web application.Crop Production/Industries, Farm Management, Production Economics,

SIMPLE AND MULTIPLE CROSS-HEDGING OF RICE BRAN

Feasibility of forward pricing sales of rice bran via cross-hedging was investigated. Corn, oats, wheat, and soybean meal futures were considered as simple and multiple cross-hedging media. Simulation results indicated that simple cross-hedging using corn futures would be most effective in reducing price risks.Demand and Price Analysis,

Analysis of systems hardware flown on LDEF. Results of the systems special investigation group

The Long Duration Exposure Facility (LDEF) was retrieved after spending 69 months in low Earth orbit (LEO). LDEF carried a remarkable variety of mechanical, electrical, thermal, and optical systems, subsystems, and components. The Systems Special Investigation Group (Systems SIG) was formed to investigate the effects of the long duration exposure to LEO on systems related hardware and to coordinate and collate all systems analysis of LDEF hardware. Discussed here is the status of the LDEF Systems SIG investigation through the end of 1991

Employee Relations Ethics and the Changing Nature of the American Workforce

Much is being written today about the changing nature of the American workforce. This article summarizes 10 of these changes: (a) global competition; (b) the changing skills of work; (c) the declining impact of unions; (d) the altered human composition of the workforce; (e) the effects of continuous improvement, downsizing, and reengineering; (f) the growing use of part-time employees; (g) the widening income gap; (h) lessened employer and employee loyalty and commitment; (i) early retirement programs; and (j) telecommunications and virtual employees. Rather than just identifying and documenting these trends, this article discusses the ethical implications of such movements. In this article, employee relations ethics is defined as treating employees properly, with respect and dignity. The term employee relations ethics is used both individually and collectively to analyze the negative human results from a moral rather than an economic perspective. The age-old clash between bottom-line mentality (economics) versus higher order thinking (ethics) is revisited with a focus on employees, not owners (old theory) or customers (new theory)

The Effectiveness of an Artificial Floating Wetland to Remove Nutrients in an Urban Stream: A Pilot-Study in the Chicago River, Chicago, IL USA

Ever expanding urbanized landscapes are increasingly impacting streams that run through them. Among other stressors, urban streams often are host to elevated concentrations of nutrients, salts, and heavy metals. The pollutants, coupled with high temperatures, are drivers of ecosystem degradation in urban streams. The installation of artificial floating wetlands (AFWs) has been successful in mitigating the effects of urbanization in lakes and wastewater treatment ponds, but rarely have they been tested in streams. This pilot-study examined the ability of an AFW to improve water quality in an urban stream. The small, 90 m2 AFW was installed to improve the aquatic habitat and aesthetics of a small section of the Chicago River, Chicago, IL USA.Water samples and in-situ measurements were collected from the surface and at 0.3 m depth of upstream and downstream of the AFW. Samples were analyzed for nitrate-as-nitrogen, phosphate, chloride, and heavy metals. Comparison of upstream and downstream waters showed that the AFW lowered the concentrations of nitrate-as-nitrogen and phosphate during the growing season by 6.9% and 6.0%, respectively. Nitrate was also removed during the dormant season; however, phosphate was not removed during that time. Plant or microbial uptake of the nutrients are believed to be the dominant mechanisms in the growing season with denitrification serving as the primary pathway in the dormant season. Despite not having a measurable effect on the water temperature, the AFW was an effective means to reduce concentrations of nitrate and phosphorus, decreasing the potential for eutrophication

If He Can Fight Like He Can Love Good Night Germany!

https://digitalcommons.library.umaine.edu/mmb-vp/1804/thumbnail.jp

Effects of thermotherapy and virus status on yield, annual growth and grape composition of Sultana

A high yielding Sultana clone, H5, infected with yellow speckle and leafroll diseases was compared over 5 harvests with 6 heat-treated H5 clones, 3 of which still contained both diseases and 3 from which leafroll had been eliminated, and also with a Thompson Seedless clone (FV B6Vl HT91) from California. There were no differences between .the untreated H5 clone and the Thompson Seedless clone which was infected with only yeilow speckle for any of the measured variables in any season.The mean yield of heat-treated H5 clones was reduced by 6 % in those which still contained both diseases and was not affected in those from which leafroll had been eliminated. The yield reduction was related to fewer inflorescences.The mean weight of annual shoot growth, berry weight, calculated bunch. weight, sugar concentration and pH and titratable acidity of juice, did not differ between the 4 groups.Long periods of heat treatment (196-938 d) produced no clones with yields or annual shoot growth superior to the untreated source clone.Except for expression of leaf symptoms associated with leafroll, all 6 heat-treated H5 clones showed no obvious morphological differences from their original source clone, nor did the heat-treated Thompson Seedless clone.Der Einßuß von Thermotherapie und Virusbefall auf Traubenertrag, Holzproduktion und Traubenqualität der Rebsorte SultanaZusammenfassung. - Der an Yellow speckle und Leafroll erkrankte ertragsstarke Sultana-Klon H5 wurde 5 Ernteperioden lang mit 6 wärmebehandelten H5-Klonen - 3 davon noch mit beiden Krankheiten, 3 nur noch mit Yellow speckle behaftet - sowie mit einem Thompson-Seedless-Klon (FV B6Vl HT91) aus Kalifornien verglichen.Zwischen dem unbehandelten H5-Klon und dem Thompson-Seedless-Klon, der nur an Yellow speckle erkrankt war, wurden in keinem Jahr irgendwelche Unterschiede der erfaßten Meßgrößen festgestellt.Der mittlere Traubenertrag der wärmebehandelten H5-Klone war bei den doppelt erkrankten Reben um 6 % verringert und bei den Leafroll-freien Reben nicht beeinflußt. Der Ertragsrückgang war mit einer geringeren Anzahl von Infloreszenzen verbunden.Die 4 Versuchsgruppen zeigten keine Unterschiede bei jährlichem Holzzuwachs, Beerengewicht und kalkuliertem Traubengewicht sowie Zuckerkonzentration, pH und titrierbarer Säure des Beerensaftes.Lange Perioden der Wärmebehandlung (196-338 d) ergaben keine Klone, die in ihrem Traubenertrag oder der Holzproduktion dem unbehandelten Ausgangsklon überlegen gewesen wären.Abgesehen von den Leafroll-Symptomen der Blätter zeigten alle 6 wärmebehandelten H5-Klone keine erkennbaren morphologischen Abweichungen von ihrem Ausgangsklon; Entsprechendes gilt für den wärmebehandelten Thompson-Seedless-Klon