5,934 research outputs found

    I-O Psychology in Aotearoa, New Zealand: A world away?

    Get PDF
    Industrial-organizational psychology has had a fairly long history in this country, dating back to around the 1920s (Jamieson & Paterson, 1993). To a large extent the field developed initially within universities, although the focus of I-O psychologists’ activities in this country has always been very applied. Inclusion of I-O psychology in university curricula originally started at the University of Canterbury (in the south island) and then Massey University (in the north island); now two other universities (University of Auckland and University of Waikato, both in the north island) also provide training programs in the field. There are about a dozen academics in psychology departments who would consider themselves to be I-O psychologists, and a small handful in management or HRM departments. Clearly the number of academics specializing in this field is very small. Although this poses challenges for the development of I-O psychology in Aotearoa New Zealand, at the same time it helps communication among us

    A cryogenic dc-dc power converter for a 100kW synchronous HTS generator at liquid nitrogen temperatures

    Get PDF
    A dc-dc converter has been developed for retrofitting inside the vacuum space of the HTS rotor of a synchronous generator. The heavy copper sections of the current leads used for energising the HTS field winding were replaced by cryogenic power electronics; consisting of the converter and a rotor control unit. The converter board was designed using an H-bridge configuration with two 5A rated wires connecting the cryogenic boards to the stator control board located on the outside of the generator and drawing power from a (5A, 50V) dc power source. The robustness of converter board was well demonstrated when it was powered up from a cold start at 82K. When charging the field winding with moderate currents (30A), the heat in-leak to the ‘cold’ rotor core was only 2W. It continued to function down to 74K, surviving several quenches. However, the quench protection function failed when injecting 75A into the field winding, resulting in the burn out of one of the DC-link capacitors. The magnitudes of the critical currents measured with the original current leads were compared to the quench currents, which was defined as the current which triggered quench protection protocol. The difference between the two currents was rather large, (~20A). However, additional measurements using a single HTS coil in liquid nitrogen found that this reduction should not be so dramatic and in the region of 4A. Our conclusions identified the converter’s switching voltage and its operating frequency as two parameters, which could have contributed to lowering the quench current. Magnetic fields and eddy currents are expected to be more prominent the field winding and its impact on the converter also need further investigation

    A Penalty Method for the Numerical Solution of Hamilton-Jacobi-Bellman (HJB) Equations in Finance

    Full text link
    We present a simple and easy to implement method for the numerical solution of a rather general class of Hamilton-Jacobi-Bellman (HJB) equations. In many cases, the considered problems have only a viscosity solution, to which, fortunately, many intuitive (e.g. finite difference based) discretisations can be shown to converge. However, especially when using fully implicit time stepping schemes with their desirable stability properties, one is still faced with the considerable task of solving the resulting nonlinear discrete system. In this paper, we introduce a penalty method which approximates the nonlinear discrete system to first order in the penalty parameter, and we show that an iterative scheme can be used to solve the penalised discrete problem in finitely many steps. We include a number of examples from mathematical finance for which the described approach yields a rigorous numerical scheme and present numerical results.Comment: 18 Pages, 4 Figures. This updated version has a slightly more detailed introduction. In the current form, the paper will appear in SIAM Journal on Numerical Analysi

    Post-anaesthetic acetonuria with reference to the puerperal state.

    Get PDF

    A History of The Cattle Pools In Barber County, Kansas

    Get PDF
    For a period during and following the Civil War there was a great demand for beef in the United States and in Europe. The building of the railroads across the nation was of great value in the transportation of cattle to meet this demand. From Texas the cattlemen began to make the long drive to the nearest rail head. Much has been written about the so called cow towns of Kansas and the part they played in the development of the state, but a point that has been overlooked for the most part is the association of cattlemen into groups for the purpose of protection and mutual aid . It is not the purpose of this paper to treat each such association in the state for to do so would involve much too broad a field . However, an attempt will be made to present the history of the cattle pools in Barber county , Kansas. The author has chosen Barber county because it is more familiar to him, and it is representative of the beginnings and growth of the cattle industry in southwestern Kansas

    On the magnetospheric ULF wave counterpart of substorm onset

    Get PDF
    One near‐ubiquitous signature of substorms observed on the ground is the azimuthal structuring of the onset auroral arc in the minutes prior to onset. Termed auroral beads, these optical signatures correspond to concurrent exponential increases in ground ultralow frequency (ULF) wave power and are likely the result of a plasma instability in the magnetosphere. Here, we present a case study showing the development of auroral beads from a Time History of Events and Macroscale Interactions during Substorms (THEMIS) all‐sky camera with near simultaneous exponential increases in auroral brightness, ionospheric and conjugate magnetotail ULF wave power, evidencing their intrinsic link. We further present a survey of magnetic field fluctuations in the magnetotail around substorm onset. We find remarkably similar superposed epoch analyses of ULF power around substorm onset from space and conjugate ionospheric observations. Examining periods of exponential wave growth, we find the ground‐ and space‐based observations to be consistent, with average growth rates of ∌0.01 s−1, lasting for ∌4 min. Cross‐correlation suggests that the space‐based observations lead those on the ground by approximately 1–1.5 min. Meanwhile, spacecraft located premidnight and ∌10 RE downtail are more likely to observe enhanced wave power. These combined observations lead us to conclude that there is a magnetospheric counterpart of auroral beads and exponentially increasing ground ULF wave power. This is likely the result of the linear phase of a magnetospheric instability, active in the magnetotail for several minutes prior to auroral breakup

    Anomalous phase of MnP at very low field

    Full text link
    Manganese phosphide MnP has been investigated for decades because of its rich magnetic phase diagram. It is well known that the MnP exhibits the ferromagnetic phase transition at \Tc=292 K and the helical magnetic phase below \TN=47 K at zero field. Recently, a novel magnetic phase transition was observed at T∗=282T^* = 282 K when the magnetic field is lower than 5 Oe. However, the nature of the new phase has not been illuminated yet. In order to reveal it, we performed the AC and the DC magnetization measurements for a single crystal MnP at very low field. A divergent behavior of the real and the imaginary part of the AC susceptibility and a sharp increase of the DC magnetization was observed at T∗T^*, indicating the magnetic phase transition at T∗T^*. Furthermore a peculiar temperature hysteresis was observed: namely, the magnetization depends on whether cooling sample to the temperature lower than \TN or not before the measurements. This hysteresis phenomenon suggests the complicated nature of the new phase and a strong relation between the magnetic state of the new phase and the helical structure.Comment: 4 pages, 2 figure

    A comprehensive analysis of multi-scale field aligned currents: Characteristics, controlling parameters, and relationships

    Get PDF
    We explore the characteristics, controlling parameters, and relationships of multi-scale field aligned currents (FACs) using a rigorous, comprehensive, and cross-platform analysis. Our unique approach combines FAC data from the Swarm satellites and the Advanced Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) to create a database of small-scale (∌10-150 km, 250 km) FACs. We examine these data for the repeatable behavior of FACs across scales (i.e., the characteristics), the dependence on the interplanetary magnetic field (IMF) orientation, and the degree to which each scale ‘departs’ from nominal large-scale specification. We retrieve new information by utilizing magnetic latitude and local time dependence, correlation analyses, and quantification of the departure of smaller from larger scales. We find that: 1) FACs characteristics and dependence on controlling parameters do not map between scales in a straight forward manner; 2) relationships between FAC scales exhibit local time dependence; and 3) the dayside high-latitude region is characterized by remarkably distinct FAC behavior when analyzed at different scales, and the locations of distinction correspond to ‘anomalous’ ionosphere-thermosphere (IT) behavior. Comparing with nominal large-scale FACs, we find that differences are characterized by a horseshoe shape, maximizing across dayside local times, and that difference magnitudes increase when smaller scale observed FACs are considered. We suggest that both new physics and increased resolution of models are required to address the multi-scale complexities. We include a summary table of our findings to provide a quick reference for differences between multi-scale FACs

    Isospin Splitting in the Baryon Octet and Decuplet

    Full text link
    Baryon mass splittings are analyzed in terms of a simple model with general pairwise interactions. At present, the Δ\Delta masses are poorly known from experiments. Improvement of these data would provide an opportunity to make a significant test of our understanding of electromagnetic and quark-mass contributions to hadronic masses. The problem of determining resonance masses from scattering and production data is discussed.Comment: 9 pages, LATEX inc. 2 LATEX "pictures", CMU-HEP91-24-R9

    Structure and spacing of cellulose microfibrils in woody cell walls of dicots

    Get PDF
    The structure of cellulose microfibrils in situ in wood from the dicotyledonous (hardwood) species cherry and birch, and the vascular tissue from sunflower stems, was examined by wide-angle X-ray and neutron scattering (WAXS and WANS) and small-angle neutron scattering (SANS). Deuteration of accessible cellulose chains followed by WANS showed that these chains were packed at similar spacings to crystalline cellulose, consistent with their inclusion in the microfibril dimensions and with a location at the surface of the microfibrils. Using the Scherrer equation and correcting for considerable lateral disorder, the microfibril dimensions of cherry, birch and sunflower microfibrils perpendicular to the [200] crystal plane were estimated as 3.0, 3.4 and 3.3 nm respectively. The lateral dimensions in other directions were more difficult to correct for disorder but appeared to be 3 nm or less. However for cherry and sunflower, the microfibril spacing estimated by SANS was about 4 nm and was insensitive to the presence of moisture. If the microfibril width was 3 nm as estimated by WAXS, the SANS spacing suggests that a non-cellulosic polymer segment might in places separate the aggregated cellulose microfibrils
    • 

    corecore