1,463 research outputs found

    Darryl Francis and the making of monetary policy, 1966-1975

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    Darryl Francis was president of the Federal Reserve Bank of St. Louis from 1966 to 1975. Throughout those years he was a leading critic of U.S. monetary policy. Francis argued in policy meetings and public venues that monetary policy should focus on maintaining a stable price level. In contrast, most policymakers at the time believed it possible to exploit a tradeoff between unemployment and inflation. While Francis attributed inflation directly to excessive growth of the money stock, other policymakers blamed labor and product market failures, fiscal policy, and commodity price shocks. Francis argued that inflation could not be controlled except by limiting the growth of monetary aggregates; other policymakers promoted price controls or other schemes. Francis favored maintaining a stable money stock growth rate at a time when monetary policy was widely interpreted as involving the manipulation of interest rates. Reviewing the debates between Francis and his Federal Reserve colleagues improves our understanding of the reasons behind the Fed’s monetary policy actions at the time and illuminates how policy views evolved within the System toward accepting price level stability as the paramount, long-run objective for monetary policy.Monetary policy

    Chemical and rheological aspects of gel formation in the California Mastitis Test

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    The rheological properties of the CMT gel were analysed. Data are presented to demonstrate that the gel is a non-homogenous, visco-elastic, non-Newtonian fluid with rheopectic, and rheodestructive behaviour. The fundamental chemistry of the CMT is reviewed and a modified theory of gel formation is presented. The implications of the rheological properties and modified theory of gel formation for an automatic sensor are discussed

    Compressibility and shear compliance of spheroidal pores: Exact derivation via the Eshelby tensor, and asymptotic expressions in limiting cases

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    AbstractWe explicitly calculate the elastic compliance of a spheroidal pore in an isotropic solid, starting from Eshelby’s tensor. The exact expressions found for the pore compressibility, P, and the shear compliance, Q, are valid for any value of the aspect ratio α, from zero (cracks) to infinity (needles). This derivation clarifies previous work on this problem, in which different methods were used in different ranges of α, or typographical errors were present. The exact expressions obtained for P and Q are quite complex and unwieldy. Simple expressions for both P and Q have previously been available for the limiting cases of infinitely thin-cracks (α=0), infinitely long-needles (α=∞), and spherical pores (α=1). We have now calculated additional terms in the asymptotic expansions, yielding relatively simple approximations for P and Q that are valid for crack-like pores having aspect ratios as high as 0.3, needle-like pores having aspect ratios as low as 3, and nearly spherical pores. Their relatively simple forms will be useful for incorporation into various schemes to estimate the effective elastic moduli

    Reactivities of electrophilic N–F fluorinating reagents

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    Electrophilic fluorination represents one of the most direct and useful methods available for the selective introduction of fluorine into organic compounds. Electrophilic fluorinating reagents of the N–F class have revolutionised the incorporation of fluorine atoms into both pharmaceutically- and agrochemically-important substrates. Since the earliest N–F reagents were commercialised in the 1990s, their reactivities have been investigated using qualitative and, more recently, quantitative methods. This review discusses the different experimental approaches employed to determine reactivities of N–F reagents, focussing on the kinetics studies reported in recent years. We make critical evaluations of the experimental approaches against each other, theoretical approaches, and their applicability towards practical problems. The opportunities for achieving more efficient synthetic electrophilic fluorination processes through kinetic understanding are highlighted

    Stereoselective Syntheses of 3’-Hydroxyamino- and 3’-Methoxyamino-2’,3’-Dideoxynucleosides

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    Aminonucleosides are used as key motifs in medicinal and bioconjugate chemistry; however, existing strategies toward 3′-hypernucleophilic amine systems do not readily deliver deoxyribo-configured products. We report diastereoselective syntheses of deoxyribo- and deoxyxylo-configured 3′-hydroxyamino- and 3′-methoxyamino-nucelosides from 3′-imine intermediates. The presence or absence of the 5′-hydroxyl-group protection dictates facial selectivity via inter- or intramolecular delivery of hydride from BH3 (borane). Protecting group screening gave one access to previously unknown 3′-methoxyamino-deoxyguanosine derivatives

    REVIEW OF CONSPECIFIC ATTRACTION AND AREA SENSITIVITY OF GRASSLAND BIRDS

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    Many species of grassland birds are area sensitive, which may exacerbate the ecological effects of the extensive loss and fragmentation of grasslands that has taken place across the northern Great Plains. However, the reasons for this area sensitivity are unclear, as vegetation structure, matrix composition, and restriction of movements among patches do not seem to provide viable explanations for species native to grasslands. Con specific attraction, whereby species are behaviorally stimulated to select habitat or establish territories near individuals of the same species, may help explain this area sensitivity. We review and discuss theoretical and empirical research on avian conspecific attraction and area sensitivity of grassland birds. While the body of literature on these subjects is growing, there have been few experimental tests of con specific attraction in grassland bird species and none that investigate its role in grassland-bird area sensitivity. We suggest that research into the role that conspecific attraction may play in grassland-bird habitat selection could provide new insights into the mechanisms behind area sensitivity in grassland birds and yield new management tools for their conservation

    Root Diseases and Blister Rust Associated with Bark Beetles (Coleoptera: Scolytidae) in Western White Pine in Idaho

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    Root systems of western white pine, Pinus montieola Douglas, were excavated with explosives and examined for pathogens. Data were also recorded on portions of the crown killed by blister rust caused by Cronartium ribieola Fisch. Statistical tests revealed a significant association between the bark beetles Dendroetonus ponderosae Hopkins and Pityogenes fossifrons (LeConte), and the root pathogen Armillariella mellea. (Vah!. ex Fr.) Karst and between beetles and all root diseases. Ninety-two percent of the trees attacked by bark beetles had root diseases, and 97% had either root diseases or blister rust. A discriminant analysis correctly classified 88% of the sample trees into two categories, trees infested with D. ponderosae or trees not infested with D. ponderosae, using the variables age (stump), diameter at 1.3 m in height, and percentage of the primary roots infected with pathogens. Major pathogenic organisms isolated from the roots included A. mellea, Phaeolus sehweinitzii (Fr.) Pat., Resinicium bieolor (Fr.) Parm., Vertieicladiella spp., and a Europhium strain. A hypothetical sequence of host tree invasion by blister rust, followed by infection by root diseases, and finally attacks by bark beetles, is postulated

    A compact holographic optical tweezers instrument

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    Holographic optical tweezers have found many applications including the construction of complex micron-scale 3D structures and the control of tools and probes for position, force, and viscosity measurement. We have developed a compact, stable, holographic optical tweezers instrument which can be easily transported and is compatible with a wide range of microscopy techniques, making it a valuable tool for collaborative research. The instrument measures approximately 30×30×35 cm and is designed around a custom inverted microscope, incorporating a fibre laser operating at 1070 nm. We designed the control software to be easily accessible for the non-specialist, and have further improved its ease of use with a multi-touch iPad interface. A high-speed camera allows multiple trapped objects to be tracked simultaneously. We demonstrate that the compact instrument is stable to 0.5 nm for a 10 s measurement time by plotting the Allan variance of the measured position of a trapped 2 μm silica bead. We also present a range of objects that have been successfully manipulated

    Deacon Draff\u27s Song

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    A man is happy as long as he does not have to pay taxes.https://egrove.olemiss.edu/kgbsides_scot/1046/thumbnail.jp

    Magneto-optical rotation and cross-phase modulation via coherently driven tripod atoms

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    We study the interaction of a weak probe field, having two orthogonally polarized components, with an optically dense medium of four-level atoms in a tripod configuration. In the presence of a coherent driving laser, electromagnetically induced transparency is attained in the medium, dramatically enhancing its linear as well as nonlinear dispersion while simultaneously suppressing the probe field absorption. We present the semiclassical and fully quantum analysis of the system. We propose an experimentally feasible setup that can induce large Faraday rotation of the probe field polarization and therefore be used for ultra-sensitive optical magnetometry. We then study the Kerr nonlinear coupling between the two components of the probe, demonstrating a novel regime of symmetric, extremely efficient cross-phase modulation, capable of fully entangling two single-photon pulses. This scheme may thus pave the way to photon-based quantum information applications, such as deterministic all-optical quantum computation, dense coding and teleportation.Comment: Corrected typo
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