259 research outputs found
Non-Uniform Channelization Methods for Next Generation SDR PMR Base Stations
Channelization in multi-standard Software-Defined
Radio base stations presents a significant challenge. In this
paper, two different channelization structures designed for a
multi-standard SDR base station are studied. As a basis for
comparing their computational efficiency and
reconfigurability, both are applied to a specific case study of a
TETRA and TEDS standards base station. Uniform narrow
band spectrum division followed by channel recombination
demonstrates greater flexibility than a non-uniform parallel
spectrum division alternative. However, computational
advantages between both structures depend on the channel
allocation patterns considered
Law, Liquor, and Love
This article discusses attempts at alcohol law reform in New Zealand between 2008 and 2017. First, it describes a major review of alcohol by the New Zealand Law Commission, headed by Sir Geoffrey Palmer, who had overseen liberalisation of alcohol regulation 25 years earlier. The main recommendations of the commission’s final report featured progressive reform of the alcohol laws regulating marketing, price, accessibility and age of purchase. Second, it outlines the response to the commission’s report by the Nationalled government, including an Alcohol Reform Bill that ignored the key recommendations of the commission. This ‘non-reform’ bill was the outcome of a political process of obfuscation, delay and inaction led by then prime minister, John Key. Third, the article describes the factors that have contributed to the lack of effective alcohol law reform, despite the review and high public support for change over the past decade. We conclude that ‘the love of money’ is at the heart of the barriers to change. Finally, we propose three main policies that would make a significant difference to reducing alcohol-related harm in New Zealand and suggest how these could be advanced
The Influence of Particle Content on the Equi-Biaxial Fatigue Behaviour of Magnetorheological Elastomers
The equi-biaxial fatigue behaviour of silicone based magnetorheological elastomers (MREs) with various volume fractions of carbonyl iron particles ranging between 15% and 35% was studied. Wöhler curves for each material were derived by cycling test samples to failure over a range of stress amplitudes. Changes in complex modulus (E*) and dynamic stored energy during the fatigue process were observed. As for other elastic solids, fatigue resistance of MREs with different particle contents was shown to be dependent on the stress amplitudes applied. MREs with low particle content showed the highest fatigue life at high stress amplitudes while MREs with high particle content exhibited the highest fatigue resistance at low stress amplitudes. E* fell with the accumulation of cycles for each material, but the change was dependent on the particle content and stress amplitude applied. However, each material failed in a range suggesting a limiting value of E* for the material between 1.22 MPa and 1.38 MPa regardless of the particle content and the magnitude of the stress amplitude. In keeping with results from previous testing, it was shown that dynamic stored energy can be used to predict the fatigue life of MREs having a wide variation in particle content
AAO Starbugs: software control and associated algorithms
The Australian Astronomical Observatory's TAIPAN instrument deploys 150
Starbug robots to position optical fibres to accuracies of 0.3 arcsec, on a 32
cm glass field plate on the focal plane of the 1.2 m UK-Schmidt telescope. This
paper describes the software system developed to control and monitor the
Starbugs, with particular emphasis on the automated path-finding algorithms,
and the metrology software which keeps track of the position and motion of
individual Starbugs as they independently move in a crowded field. The software
employs a tiered approach to find a collision-free path for every Starbug, from
its current position to its target location. This consists of three
path-finding stages of increasing complexity and computational cost. For each
Starbug a path is attempted using a simple method. If unsuccessful,
subsequently more complex (and expensive) methods are tried until a valid path
is found or the target is flagged as unreachable.Comment: 10 pages, to be published in Proc. SPIE 9913, Software and
Cyberinfrastructure for Astronomy IV; 201
Construction and properties of a mutant of herpes simplex virus type 1 with glycoprotein H coding sequences deleted
A mutant of herpes simplex virus type 1 (HSV-1) in which glycoprotein H (gH) coding sequences were deleted and replaced by the Escherichia coli lacZ gene under the control of the human cytomegalovirus IE-1 gene promoter was constructed. The mutant was propagated in Vero cells which contained multiple copies of the HSV-1 gH gene under the control of the HSV-1 gD promoter and which therefore provide gH in trans following HSV-1 infection. Phenotypically gH-negative virions were obtained by a single growth cycle in Vero cells. These virions were noninfectious, as judged by plaque assay and by expression of I-galactosidase following high-multiplicity infection, but partial recovery of infectivity was achieved by using the fusogenic agent polyethylene glycol. Adsorption of gH-negative virions to cells blocked the adsorption of superinfecting wild-type virus, a result in contrast to that obtained with gD-negative virions (D. C. Johnson and M. W. Ligas, J. Virol. 62:4605-4612, 1988). The simplest conclusion is that gH is required for membrane fusion but not for receptor binding, a conclusion consistent with the conservation of gH in all herpesviruses
Generation of competent bone marrow-derived antigen presenting cells from the deer mouse (Peromyscus maniculatus)
BACKGROUND: Human infections with Sin Nombre virus (SNV) and related New World hantaviruses often lead to hantavirus cardiopulmonary syndrome (HCPS), a sometimes fatal illness. Lungs of patients who die from HCPS exhibit cytokine-producing mononuclear infiltrates and pronounced pulmonary inflammation. Deer mice (Peromyscus maniculatus) are the principal natural hosts of SNV, in which the virus establishes life-long persistence without conspicuous pathology. Little is known about the mechanisms SNV employs to evade the immune response of deer mice, and experimental examination of this question has been difficult because of a lack of methodologies for examining such responses during infection. One such deficiency is our inability to characterize T cell responses because susceptible syngeneic deer mice are not available. RESULTS: To solve this problem, we have developed an in vitro method of expanding and generating competent antigen presenting cells (APC) from deer mouse bone marrow using commercially-available house mouse (Mus musculus) granulocyte-macrophage colony stimulating factor. These cells are capable of processing and presenting soluble protein to antigen-specific autologous helper T cells in vitro. Inclusion of antigen-specific deer mouse antibody augments T cell stimulation, presumably through Fc receptor-mediated endocytosis. CONCLUSIONS: The use of these APC has allowed us to dramatically expand deer mouse helper T cells in culture and should permit extensive characterization of T cell epitopes. Considering the evolutionary divergence between deer mice and house mice, it is probable that this method will be useful to other investigators using unconventional models of rodent-borne diseases
Identifying Stars of Mass >150 Msun from Their Eclipse by a Binary Companion
We examine the possibility that very massive stars greatly exceeding the
commonly adopted stellar mass limit of 150 Msun may be present in young star
clusters in the local universe. We identify ten candidate clusters, some of
which may host stars with masses up to 600 Msun formed via runaway collisions.
We estimate the probabilities of these very massive stars being in eclipsing
binaries to be >30%. Although most of these systems cannot be resolved at
present, their transits can be detected at distances of 3 Mpc even under the
contamination of the background cluster light, due to the large associated
luminosities ~10^7 Lsun and mean transit depths of ~10^6 Lsun. Discovery of
very massive eclipsing binaries would flag possible progenitors of
pair-instability supernovae and intermediate-mass black holes.Comment: 5 pages, 1 figure, 1 table. Submitted to MNRA
The Sydney-AAO Multi-object Integral field spectrograph (SAMI)
We demonstrate a novel technology that combines the power of the multi-object
spectrograph with the spatial multiplex advantage of an integral field
spectrograph (IFS). The Sydney-AAO Multi-object IFS (SAMI) is a prototype
wide-field system at the Anglo-Australian Telescope (AAT) that allows 13
imaging fibre bundles ("hexabundles") to be deployed over a 1-degree diameter
field of view. Each hexabundle comprises 61 lightly-fused multimode fibres with
reduced cladding and yields a 75 percent filling factor. Each fibre core
diameter subtends 1.6 arcseconds on the sky and each hexabundle has a field of
view of 15 arcseconds diameter. The fibres are fed to the flexible AAOmega
double-beam spectrograph, which can be used at a range of spectral resolutions
(R=lambda/delta(lambda) ~ 1700-13000) over the optical spectrum (3700-9500A).
We present the first spectroscopic results obtained with SAMI for a sample of
galaxies at z~0.05. We discuss the prospects of implementing hexabundles at a
much higher multiplex over wider fields of view in order to carry out
spatially--resolved spectroscopic surveys of 10^4 to 10^5 galaxies.Comment: 24 pages, 16 figures. Accepted by MNRA
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