20,580 research outputs found

    The Long and the Short End of the Term Structure of Policy Rules

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    We first document a large secular shift in the estimated response of the entire term structure of interest rates to inflation and output in the United States. The shift occurred in the early 1980s. We then derive an equation that links these responses to the coefficients of the central bank's monetary policy rule for the short-term interest rate. The equation reveals two countervailing forces that help explain and understand the nature of the link and how its sign is determined. Using this equation, we show that a shift in the policy rule in the early 1980s provides an explanation for the observed shift in the term structure. We also explore a shift in the policy rule in the 2002-2005 period and its possible effect on long-term rates.

    THE LOCATION DECISION OF HARDWOOD MANUFACTURING IN THE NORTHERN AND CENTRAL APPALACHIAN STATES

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    This study's objective is to identify and understand the factors important to hardwood processors' location decisions in the northern and central Appalachian region. Concepts from neoclassical and behavioral location theories were integrated to develop a general framework for analyzing these decisions. Logit regression analysis was used to determine those establishment characteristics related to the likelihood of location search. To a great extent, establishments locate based on personal ties and do not conduct searches. Most variables found to influence the likelihood of search are not controllable by state or local governments. The implications are that existing establishments should be targeted for retention and expansion, rather than focusing on recruitment.Community/Rural/Urban Development, Industrial Organization,

    Identifying Student Difficulties with Entropy, Heat Engines, and the Carnot Cycle

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    We report on several specific student difficulties regarding the Second Law of Thermodynamics in the context of heat engines within upper-division undergraduates thermal physics courses. Data come from ungraded written surveys, graded homework assignments, and videotaped classroom observations of tutorial activities. Written data show that students in these courses do not clearly articulate the connection between the Carnot cycle and the Second Law after lecture instruction. This result is consistent both within and across student populations. Observation data provide evidence for myriad difficulties related to entropy and heat engines, including students' struggles in reasoning about situations that are physically impossible and failures to differentiate between differential and net changes of state properties of a system. Results herein may be seen as the application of previously documented difficulties in the context of heat engines, but others are novel and emphasize the subtle and complex nature of cyclic processes and heat engines, which are central to the teaching and learning of thermodynamics and its applications. Moreover, the sophistication of these difficulties is indicative of the more advanced thinking required of students at the upper division, whose developing knowledge and understanding give rise to questions and struggles that are inaccessible to novices

    Ghost of a Shell: Magnetic Fields of Galactic Supershell GSH 006−-15++7

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    We identify a counterpart to a Galactic supershell in diffuse radio polarisation, and use this to determine the magnetic fields associated with this object. GSH 006−-15++7 has perturbed the polarised emission at 2.3 \,GHz, as observed in the S-band Polarisation All Sky Survey (S-PASS), acting as a Faraday screen. We model the Faraday rotation over the shell, and produce a map of Faraday depth over the area across it. Such models require information about the polarised emission behind the screen, which we obtain from the Wilkinson Microwave Anisotropy Probe (WMAP), scaled from 23 \,GHz to 2.3 \,GHz, to estimate the synchrotron background behind GSH 006−-15++7. Using the modelled Faraday thickness we determine the magnitude and the plane-of-the-sky structure of the line-of-sight magnetic field in the shell. We find a peak line-of-sight field strength of ∣B∄∣peak=2.0+0.01−0.7 Ό|B_\parallel|_\text{peak} = 2.0\substack{+0.01 \\ -0.7}\,\muG. Our measurement probes weak magnetic fields in a low-density regime (number densities of ∌0.4 \sim0.4\,cm−3^{-3}) of the ISM, thus providing crucial information about the magnetic fields in the partially-ionised phase.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society. 19 pages, 19 figure

    AN OVERVIEW OF THE CLASSIFICATION AND EVOLUTION OF THE MAJOR SCARAB BEETLE CLADES (COLEOPTERA: SCARABAEOIDEA) BASED ON PRELIMINARY MOLECULAR ANALYSES

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    We present a preliminary overview of our molecular phylogenetics research on the superfamily Scarabaeoidea. The molecular data consists of 28S ribosomal DNA sequences (mainly D2 and D3 expansion regions) for over 600 taxa and 18S ribosomal DNA sequences (mainly E17 to E35 expansion regions) for over 150 representative taxa within the lineages sampled. Based on our preliminary molecular phylogenetic results, Scarabaeoidea includes three major groups: 1) Geotrupidae, Passalidae, and Pleocomidae; 2) Lucanidae, Diphyllostomatidae, Trogidae, and Glaresidae; and 3) Hybosoridae, Ochodaeidae, Glaphyridae, and Scarabaeidae. The broad evolutionary patterns within the Scarabaeoidea are discussed with respect to phylogeny and evolution

    Phase-resolved Crab Studies with a Cryogenic TES Spectrophotometer

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    We are developing time- and energy-resolved near-IR/optical/UV photon detectors based on sharp superconducting-normal transition edges in thin films. We report observations of the Crab pulsar made during prototype testing at the McDonald 2.7m telescope with a fiber-coupled transition-edge sensor (TES) system. These data show substantial (d[alpha]~0.3), rapid variations in the spectral index through the pulse profile, with a strong phase-varying IR break across our energy band. These variations correlate with X-ray spectral variations, but no single synchrotron population can account for the full Spectral Energy Distribution (SED). We also describe test spectrophotopolarimetry observations probing the energy dependence of the polarization sweep; this may provide a new key to understanding the radiating particle population.Comment: 12 pages, 10 figures -- to appear in ApJ V56

    Spectroscopy of Seven Cataclysmic Variables with Periods Above Five Hours

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    We present spectroscopy of seven cataclysmic variable stars with orbital periods P(orb) greater than 5 hours, all but one of which are known to be dwarf novae. Using radial velocity measurements we improve on previous orbital period determinations, or derive periods for the first time. The stars and their periods are TT Crt, 0.2683522(5) d; EZ Del, 0.2234(5) d; LL Lyr, 0.249069(4) d; UY Pup, 0.479269(7) d; RY Ser, 0.3009(4) d; CH UMa, 0.3431843(6) d; and SDSS J081321+452809, 0.2890(4) d. For each of the systems we detect the spectrum of the secondary star, estimate its spectral type, and derive a distance based on the surface brightness and Roche lobe constraints. In five systems we also measure the radial velocity curve of the secondary star, estimate orbital inclinations, and where possible estimate distances based on the MV(max) vs.P(orb) relation found by Warner. In concordance with previous studies, we find that all the secondary stars have, to varying degrees, cooler spectral types than would be expected if they were on the main sequence at the measured orbital period.Comment: 25 pages, 2 figures, accepted for Publications of the Astronomical Society of the Pacifi

    1993 Iowa Agricultural Disaster Preliminary Estimates

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    On July 27, 1993 a multidisciplinary committee was formed at Iowa State University to provide preliminary estimates for the economic effects of the 1993 floods on Iowa\u27s agricultural enterprises. This report summarizes the committee\u27s initial estimates of the losses by broad economic category; detailed income information was not available at the time the report was written. The report does not provide estimates of lost income due to agribusiness work stoppages nor direct losses of livestock, buildings, fences, and machinery
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