25,333 research outputs found

    Remedial training: Will CRM work for everyone

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    The subject of those pilots who seem unresponsive to Cockpit Resource Management (CRM) training is addressed. Attention is directed to the need and opportunity for remedial action. Emphasis is given to the requirement for new perspectives and additional training resources. It is also argued that, contrary to conventional training wisdom, such individuals do not represent a hard core which is beyond assistance. Some evidence is offered that such a new perspective will lend itself to a wider appreciation of certain specific training needs. The role of appropriately trained specialists is briefly outlined, and a selected bibliography is attached. The combined experiences of several Pilot Advisory Groups (PAG's) within IFALPA member association form the basis for this discussion. It does not purport to desribe the activities of any one PAG. While much of the activities of PAG's have no relevance to CRM, there are clearly some very important points of intersection. The relevance of these points to diagnostic skills, and remedial training in the general domain of CRM is made obvious

    13 Years of Timing of PSR B1259-63

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    This paper summarizes the results of 13 years of timing observations of a unique binary pulsar, PSR B1259−-63, which has a massive B2e star companion. The data span encompasses four complete orbits and includes the periastron passages in 1990, 1994, 1997 and 2000. Changes in dispersion measure occurring around the 1994, 1997 and 2000 periastrons are measured and accounted for in the timing analysis. There is good evidence for a small glitch in the pulsar period in 1997 August, not long after the 1997 periastron, and a significant frequency second derivative indicating timing noise. We find that spin-orbit coupling with secular changes in periastron longitude and projected semi-major axis (xx) cannot account for the observed period variations over the whole data set. While fitting the data fairly well, changes in pulsar period parameters at each periastron seem ruled out both by X-ray observations and by the large apparent changes in pulsar frequency derivative. Essentially all of the systematic period variations are accounted for by a model consisting of the 1997 August glitch and step changes in xx at each periastron. These changes must be due to changes in the orbit inclination, but we can find no plausible mechanism to account for them. It is possible that timing noise may mask the actual changes in orbital parameters at each periastron, but the good fit to the data of the xx step-change model suggests that short-term timing noise is not significant.Comment: 9 pages, 7 figures, accepted by MNRA

    Enriching the Learning Experience: A CALM Approach.

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    This paper outlines and evaluates a new learning strategy implemented in the Faculty of Economics and Commerce at the University of Melbourne. The strategy is an Internet based assignment delivery and assessment system designed to (i) equip students to make link between macroeconomic theory and important real-world issues, (ii) develop positive attitudes to the subject (iii) develop deep approaches to learning (iv) develop a facility for critical analysis and problem solving and (v) develop effective study habits. Using a multi-dimensional evaluation strategy, the indications are that the new approach has succeeded in its aims.MACROECONOMICS ; TECHNOLOGY ; NETWORK ANALYSIS

    Polarisation profiles of southern pulsars at 3.1 GHz

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    We present polarisation profiles for 48 southern pulsars observed with the new 10-cm receiver at the Parkes telescope. We have exploited the low system temperature and high bandwidth of the receiver to obtain profiles which have good signal to noise for most of our sample at this relatively high frequency. Although, as expected, a number of profiles are less linearly polarised at 3.1 GHz than at lower frequencies, we identify some pulsars and particular components of profiles in other pulsars which have increased linear polarisation at this frequency. We discuss the dependence of linear polarisation with frequency in the context of a model in which emission consists of the superposition of two, orthogonally polarised modes. We show that a simple model, in which the orthogonal modes have different spectral indices, can explain many of the observed properties of the frequency evolution of both the linear polarisation and the total power, such as the high degree of linear polarisation seen at all frequencies in some high spin-down, young pulsars. Nearly all the position angle profiles show deviations from the rotating vector model; this appears to be a general feature of high-frequency polarisation observations.Comment: Accepted for publication in MNRA

    The evolution of the moon and the terrestrial planets

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    The thermal evolutions of the Moon, Mars, Venus and Mercury are calculated theoretically starting from cosmochemical condensation models. An assortment of geological, geochemical and geophysical data are used to constrain both the present day temperatures and the thermal histories of the planets' interiors. Such data imply that the planets were heated during or shortly after formation and that all the terrestrial planets started their differentiations early in their history. The moon, smallest in size, is characterized as a differentiated body with a crust, a thick solid mantle and an interior region which may be partially molten. Mars, intermediate in size, is assumed to have differentiated an Fe-FeS core. Venus is characterized as a planet not unlike the earth in many respects. Core formation has occurred probably during the first billion years after the formation. Mercury, which probably has a large core, may have a 500 km thick solid lithosphere and a partially molten core if it is assumed that some heat sources exist in the core

    NMR Determination of an Incommensurate Helical Antiferromagnetic Structure in EuCo2As2

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    We report 153^{153}Eu, 75^{75}As and 59^{59}Co nuclear magnetic resonance (NMR) results on EuCo2_2As2_2 single crystal. Observations of 153^{153}Eu and 75^{75}As NMR spectra in zero magnetic field at 4.3 K below an antiferromagnetic (AFM) ordering temperature TNT_{\rm N} = 45 K and its external magnetic field dependence clearly evidence an incommensurate helical AFM structure in EuCo2_2As2_2. Furthermore, based on 59^{59}Co NMR data in both the paramagnetic and the incommensurate AFM states, we have determined the model-independent value of the AFM propagation vector k{\bf k} = (0, 0, 0.73 ±\pm 0.07)2π\pi/cc where cc is the cc lattice parameter. Thus the incommensurate helical AFM state was characterized by only NMR data with model-independent analyses, showing NMR to be a unique tool for determination of the spin structure in incommensurate helical AFMs.Comment: 6 pages, 4 figures, accepted for publication in Phys.Rev.

    The 2000 Periastron Passage of PSR B1259-63

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    We report here on a sequence of 28 observations of the binary pulsar system PSR B1259-63/SS2883 at four radio frequencies made with the Australia Telescope Compact Array around the time of the 2000 periastron passage. Observations made on 2000 Sep 1 show that the pulsar's apparent rotation measure (RM) reached a maximum of −14800±1800-14800 \pm 1800 rad m−2^{-2}, some 700 times the value measured away from periastron, and is the largest astrophysical RM measured. This value, combined with the dispersion measure implies a magnetic field in the Be star's wind of 6 mG. We find that the light curve of the unpulsed emission is similar to that obtained during the 1997 periastron but that differences in detail imply that the emission disc of the Be star is thicker and/or of higher density. The behaviour of the light curve at late times is best modelled by the adiabatic expansion of a synchrotron bubble formed in the pulsar/disc interaction. The expansion rate of the bubble ∼12\sim 12 km s−1^{-1} is surprisingly low but the derived magnetic field of 1.6 G close to that expected.Comment: 8 pages, 6 figures, 3 tables, LaTeX (mn.sty). Accepted for publication in the Monthly Notices of the Royal Astronomical Society. Also available at http://astronomy.swin.edu.au/staff/tconnors/publications.htm
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