The timing and funding of Fedwire funds transfers

An examination of the Federal Reserve’s Fedwire Funds Transfer service reveals that the highest concentration of funds-transfer value occurs in the late afternoon. The authors attribute this activity peak to attempts by banks (and their customers) to coordinate payment timing more closely. By synchronizing payments, banks can take advantage of incoming funds to make outgoing payments—especially during periods of heavy payment traffic. Conversely, during off-peak times, banks must rely more on account balances or overdrafts to fund payments, which increases the cost of making payments. For this reason, banks time their payments to coincide with an activity peak, thereby reinforcing the peak.Fedwire ; Payment systems

Lunar mining of oxygen using fluorine

Experiments during the first year of the project were directed towards generating elemental fluorine via the electrolysis of anhydrous molten fluorides. Na2SiF6 was dissolved in either molten NaBF4 or a eutectic (minimum-melting) mixture of KF-LiF-NaF and electrolyzed between 450 and 600 C to Si metal at the cathode and F2 gas at the anode. Ar gas was continuously passed through the system and F2 was trapped in a KBr furnace. Various anode and cathode materials were investigated. Despite many experimental difficulties, the capability of the process to produce elemental fluorine was demonstrated

Dim-Red-Light-Induced Increase in Polar Auxin Transport in Cucumber Seedlings: I. Development of Altered Capacity, Velocity, and Response to Inhibitors

We have developed and characterized a system to analyze light effects on auxin transport independent of photosynthetic effects. Polar transport of [3H]indole-3-acetic acid through hypocotyl segments from etiolated cucumber (Cucumis sativus L.) seedlings was increased in seedlings grown in dim-red light (DRL) (0.5 μmol m−2 s−1) relative to seedlings grown in darkness. Both transport velocity and transport intensity (export rate) were increased by at least a factor of 2. Tissue formed in DRL completely acquired the higher transport capacity within 50 h, but tissue already differentiated in darkness acquired only a partial increase in transport capacity within 50 h of DRL, indicating a developmental window for light induction of commitment to changes in auxin transport. This light-induced change probably manifests itself by alteration of function of the auxin efflux carrier, as revealed using specific transport inhibitors. Relative to dark controls, DRL-grown seedlings were differentially less sensitive to two inhibitors of polar auxin transport, N-(naphth-1-yl) phthalamic acid and 2,3,5-triiodobenzoic acid. On the basis of these data, we propose that the auxin efflux carrier is a key target of light regulation during photomorphogenesis

INTEGRATING MATHEMATICAL AND SYMBOLIC MODELS THROUGH AESOP: AN EXPERT FOR STOCK OPTIONS PRICING

This paper reports on an effort to integrate symbolic and mathematical models to tailor the optimal output of an operations research model to the particular domain of a decision maker. AESOP combines the Black-Scholes model of stock options pricing with an expert system; the integrated model is designed for use by an options specialist on the American Stock Exchange. The specialist makes a number of adjustments to the output of the mathematical model; the purpose of the symbolic model is to make as many of these modifications as possible automatically. The paper reports on the development and structure of AESOP and presents data on its use.Information Systems Working Papers Serie

Probing the DNA sequence specificity of Escherichia coli RECA protein

Escherichia coli RecA protein catalyzes the central DNA strand-exchange step of homologous recombination, which is essential for the repair of double-stranded DNA breaks. In this reaction, RecA first polymerizes on single-stranded DNA (ssDNA) to form a right-handed helical filament with one monomer per 3 nt of ssDNA. RecA generally binds to any sequence of ssDNA but has a preference for GT-rich sequences, as found in the recombination hot spot Chi (5′-GCTGGTGG-3′). When this sequence is located within an oligonucleotide, binding of RecA is phased relative to it, with a periodicity of three nucleotides. This implies that there are three separate nucleotide-binding sites within a RecA monomer that may exhibit preferences for the four different nucleotides. Here we have used a RecA coprotease assay to further probe the ssDNA sequence specificity of E.coli RecA protein. The extent of self-cleavage of a λ repressor fragment in the presence of RecA, ADP-AlF(4) and 64 different trinucleotide-repeating 15mer oligonucleotides was determined. The coprotease activity of RecA is strongly dependent on the ssDNA sequence, with TGG-repeating sequences giving by far the highest coprotease activity, and GC and AT-rich sequences the lowest. For selected trinucleotide-repeating sequences, the DNA-dependent ATPase and DNA-binding activities of RecA were also determined. The DNA-binding and coprotease activities of RecA have the same sequence dependence, which is essentially opposite to that of the ATPase activity of RecA. The implications with regard to the biological mechanism of RecA are discussed

Interpreting Forestry Economic Contribution Reports: A User\u27s Guide

State agencies and Extension professionals often employ IMPLAN software and associated data to conduct economic contribution analyses of the forest sector. Economic contribution reports often vary with regard to modeling, results presentation, and interpretation of estimates. We present practical guidelines for report users on how to better understand input–output modeling and interpret forestry economic contribution reports. We discuss strategies for understanding basic terminology, aspects of IMPLAN software, and the difference between economic contribution and economic impacts, among other concepts