4,205 research outputs found

    Cluster or Capture? Manufacturing Foreign Direct Investment, External Economies and Agglomeration

    Full text link
    This review of the external economies associated with manufacturing FDI in host economies argues that the balance of forces of internalisation and externalisation is currently skewed towards the former and the interests of MNEs rather than the latter and the interests of local and national communities. A stylised comparison of developmental and competition state interventions suggests that in the absence of effective and co-ordinated interventions by governments, there will commonly be a failure of the logic of internalisation to permit localised externalisation

    Gyrotron experiments employing a field emission array cathode

    Get PDF
    The design and operation of a field emission array (FEA) cathode and the subsequent demonstration of the first FEA gyrotron are presented. Up to 10 mA from 30 000 tips was achieved reproducibly from each of ten chips in a gyrotron environment, namely, a vacuum 1 x 10(-8) mbar, -50 kV potential with multiple chip operation, The design parameters of the FEA gun were similar to those of a magnetron injection gun with an achievable electron beam current of 50-100 mA and measured power 720 W cw. Coherent microwave radiation was detected in both TE(02) at 30.1 GHz and TE(03) at 43.6 GHz, with a starting current of 1 mA

    Fabrication and performance analysis of 4-sq cm indium tin oxide/InP photovoltaic solar cells

    Get PDF
    Large-area photovoltaic solar cells based on direct current magnetron sputter deposition of indium tin oxide (ITO) into single-crystal p-InP substrates demonstrated both the radiation hardness and high performance necessary for extraterrestrial applications. A small-scale production project was initiated in which approximately 50 ITO/InP cells are being produced. The procedures used in this small-scale production of 4-sq cm ITO/InP cells are presented and discussed. The discussion includes analyses of performance range of all available production cells, and device performance data of the best cells thus far produced. Additionally, processing experience gained from the production of these cells is discussed, indicating other issues that may be encountered when large-scale productions are begun

    In vivo imaging of pyrrole-imidazole polyamides with positron emission tomography

    Get PDF
    The biodistribution profiles in mice of two pyrrole-imidazole polyamides were determined by PET. Pyrrole-imidazole polyamides are a class of small molecules that can be programmed to bind a broad repertoire of DNA sequences, disrupt transcription factor-DNA interfaces, and modulate gene expression pathways in cell culture experiments. The 18F-radiolabeled polyamides were prepared by oxime ligation between 4-[18F]-fluorobenzaldehyde and a hydroxylamine moiety at the polyamide C terminus. Small animal PET imaging of radiolabeled polyamides administered to mice revealed distinct differences in the biodistribution of a 5-ring β-linked polyamide versus an 8-ring hairpin, which exhibited better overall bioavailability. In vivo imaging of pyrrole-imidazole polyamides by PET is a minimum first step toward the translation of polyamide-based gene regulation from cell culture to small animal studies

    On the structure of non-full-rank perfect codes

    Full text link
    The Krotov combining construction of perfect 1-error-correcting binary codes from 2000 and a theorem of Heden saying that every non-full-rank perfect 1-error-correcting binary code can be constructed by this combining construction is generalized to the qq-ary case. Simply, every non-full-rank perfect code CC is the union of a well-defined family of μ\mu-components KμK_\mu, where μ\mu belongs to an "outer" perfect code C∗C^*, and these components are at distance three from each other. Components from distinct codes can thus freely be combined to obtain new perfect codes. The Phelps general product construction of perfect binary code from 1984 is generalized to obtain μ\mu-components, and new lower bounds on the number of perfect 1-error-correcting qq-ary codes are presented.Comment: 8 page

    A tapered multi-gap multi-aperture pseudospark-sourced electron gun based X-band slow wave oscillator

    Get PDF
    The experimental study of a tapered, multi-gap, multi-aperture pseudospark-sourced electron gun based X-band plasma assisted slow wave oscillator is presented. The designed electron gun is based on the pseudospark discharge concept and has been used to generate a high current density and high energy electron beam simultaneously. The distribution of apertures has been arranged such that the field penetration potency inside the backspace of the hollow-cathode is different while passing through the tapered gap region. This leads to non-concurrent ignition of the discharge through all the channels which is, in general, quite challenging in the case of multi-aperture plasma cathode electron gun geometries. Multiple and successive hollow cathode phases are reported from this electron gun geometry, which have been confirmed using simulations. This geometry also has led to the achievement of ∼71% fill factor inside the slow wave oscillator for an electron beam of energy of 20 keV and a beam current density in the range of 115-190 A/cm2 at a working argon gas pressure of 18 Pa. The oscillator has generated broadband microwave output in the frequency range of 10-11.7 GHz with a peak power of ∼10 kW for ∼50 ns

    Effect of high-dose melphalan on marrow and intestinal epithelium in mice pretreated with cyclophosphamide.

    Get PDF
    The lethal effect of high-dose melphalan in mice could be offset by pretreatment with cyclophosphamide, cytosine arabinoside or low-dose melphalan. The reason for improved survival is unclear. Althoug animals given high-dose melphalan died with symptoms of gut death, in only one instance, that with low-dose melphalan itself, did pretreatment protect the intestinal epithelium as measured by the microcolony assay. A small enhancement in the recovery of the haemopoietic tissue in pretreated animals was noted, although this on its own is unlikely to explain the phenomenon. Experiments in tumour-bearing mice showed that pretreatment with cyclophosphamide did not reduce the toxicity of melphalan to the Lewis lung carcinoma

    Collisional kinetics of non-uniform electric field, low-pressure, direct-current discharges in H2_{2}

    Full text link
    A model of the collisional kinetics of energetic hydrogen atoms, molecules, and ions in pure H2_2 discharges is used to predict Hα_\alpha emission profiles and spatial distributions of emission from the cathode regions of low-pressure, weakly-ionized discharges for comparison with a wide variety of experiments. Positive and negative ion energy distributions are also predicted. The model developed for spatially uniform electric fields and current densities less than 10−310^{-3} A/m2^2 is extended to non-uniform electric fields, current densities of 10310^{3} A/m2^2, and electric field to gas density ratios E/N=1.3E/N = 1.3 MTd at 0.002 to 5 Torr pressure. (1 Td = 10−2110^{-21} V m2^2 and 1 Torr = 133 Pa) The observed far-wing Doppler broadening and spatial distribution of the Hα_\alpha emission is consistent with reactions among H+^+, H2+_2^+, H3+_3^+, and H−H^-H ions, fast H atoms, and fast H2_2 molecules, and with reflection, excitation, and attachment to fast H atoms at surfaces. The Hα_\alpha excitation and H−^- formation occur principally by collisions of fast H, fast H2_2, and H+^+ with H2_2. Simplifications include using a one-dimensional geometry, a multi-beam transport model, and the average cathode-fall electric field. The Hα_\alpha emission is linear with current density over eight orders of magnitude. The calculated ion energy distributions agree satisfactorily with experiment for H2+_2^+ and H3+_3^+, but are only in qualitative agreement for H+^+ and H−^-. The experiments successfully modeled range from short-gap, parallel-plane glow discharges to beam-like, electrostatic-confinement discharges.Comment: Submitted to Plasmas Sources Science and Technology 8/18/201

    On the form of growing strings

    Full text link
    Patterns and forms adopted by Nature, such as the shape of living cells, the geometry of shells and the branched structure of plants, are often the result of simple dynamical paradigms. Here we show that a growing self-interacting string attached to a tracking origin, modeled to resemble nascent polypeptides in vivo, develops helical structures which are more pronounced at the growing end. We also show that the dynamic growth ensemble shares several features of an equilibrium ensemble in which the growing end of the polymer is under an effective stretching force. A statistical analysis of native states of proteins shows that the signature of this non-equilibrium phenomenon has been fixed by evolution at the C-terminus, the growing end of a nascent protein. These findings suggest that a generic non-equilibrium growth process might have provided an additional evolutionary advantage for nascent proteins by favoring the preferential selection of helical structures.Comment: 4 pages, 3 figures. Accepted for publication in Phys. Rev. Let

    Enhancing adoption of improved grazing and fire management practices in northern Australia: Bio-economic analysis and regional assessment of management options

    Get PDF
    In this project we enhanced two existing simulation models, GRASP and ENTERPRISE, and used these alone and in combination to evaluate current and candidate ‘best practice’ management options for extensive grazing lands across 6 regions in Queensland and the Northern Territory. The main management options of interest were stocking rate, pasture spelling and fire management. Regions included the Victoria River District, Burdekin woodlands, Fitzroy woodlands, Mitchell grasslands of western Queensland, Mitchell grasslands of the Barkly region, and the Maranoa-Balonne woodlands. Regional workshops with local technical specialists and producers guided and evaluated model outputs. Modelled scenarios of different degrees of stocking rate variability over time suggested that annual increases and decreases of around 10- 25% per year in total stock numbers per property, in line with changing pasture availability, give improved financial outcomes as well as ensuring good pasture condition. Simulations within specific climate windows can produce results where fixed stocking rates perform better than some degree of variation, but these do not appear to be common. Testing of various wet season spelling regimes suggested that spelling for at least 6 months in a four-year period provided accelerated improvement in pasture condition on the spelled paddocks. If animals from the spelled paddocks were accommodated on other paddocks, however, adverse impacts could occur on these stocked-up paddocks if they experienced successive years of higher than safe utilisation levels. Net benefits of spelling regimes for the whole property can therefore be less than expected. Testing of various fire regimes suggested that use of fire to manage unwanted woody vegetation is economic when woody cover is sufficient to be impacting pasture production but not so dense as to be preventing its regular use (through lack of fine fuel)
    • …
    corecore