4,081 research outputs found
Three undescribed pathogenic Phytophthora taxa from the south-west of Western Australia
The Phytophthora culture collection of the Vegetation Health Service of the Department of Environment and Conservation of Western Australia (WA) has been re-evaluated using DNA sequencing (Burgess et al., 2009). This has revealed many undescribed taxa previously classified as known morpho-species, one of which has recently been described as P. multivora (Scott et al., 2009).
The aim of this study was to describe three of these taxa, all of which occur in WA native ecosystems. They were compared with both the morphological species to which they are most similar and their closest phylogenetic relatives. In addition, the pathogenicity of these taxa was assessed in glasshouse trials
The Influence of Topography on the Formation of Temporary Bright Patches on Mars
Influence of topography on formation of bright patches on Mar
Spin frequency distributions of binary millisecond pulsars
Rotation-powered millisecond radio pulsars have been spun up to their present
spin period by a - yr long X-ray-bright phase of accretion of
matter and angular momentum in a low-to-intermediate mass binary system.
Recently, the discovery of transitional pulsars that alternate cyclically
between accretion and rotation-powered states on time scales of a few years or
shorter, has demonstrated this evolutionary scenario. Here, we present a
thorough statistical analysis of the spin distributions of the various classes
of millisecond pulsars to assess the evolution of their spin period between the
different stages. Accreting sources that showed oscillations exclusively during
thermonuclear type I X-ray bursts (nuclear-powered millisecond pulsars) are
found to be significantly faster than rotation-powered sources, while accreting
sources that possess a magnetosphere and show coherent pulsations (accreting
millisecond pulsars) are not. On the other hand, if accreting millisecond
pulsars and eclipsing rotation-powered millisecond pulsars form a common class
of transitional pulsars, these are shown to have a spin distribution
intermediate between the faster nuclear-powered millisecond pulsars and the
slower non-eclipsing rotation-powered millisecond pulsars. We interpret these
findings in terms of a spin-down due to the decreasing mass-accretion rate
during the latest stages of the accretion phase, and in terms of the different
orbital evolutionary channels mapped by the various classes of pulsars. We
summarize possible instrumental selection effects, showing that even if an
unbiased sample of pulsars is still lacking, their influence on the results of
the presented analysis is reduced by recent improvements in instrumentation and
searching techniques.Comment: Accepted for publication in A&A (6 pages, 4 figures
The Analysis of design and manufacturing tasks using haptic and immersive VR - Some case studies
The use of virtual reality in interactive design and manufacture has been researched extensively but the practical application of this technology in industry is still very much in its infancy. This is surprising as one would have expected that, after some 30 years of research commercial applications of interactive design or manufacturing planning and analysis would be widespread throughout the product design domain. One of the major but less well known advantages of VR technology is that logging the user gives a great deal of rich data which can be used to automatically generate designs or manufacturing instructions, analyse design and manufacturing tasks, map engineering processes and, tentatively, acquire expert knowledge. The authors feel that the benefits of VR in these areas have not been fully disseminated to the wider industrial community and - with the advent of cheaper PC-based VR solutions - perhaps a wider appreciation of the capabilities of this type of technology may encourage companies to adopt VR solutions for some of their product design processes. With this in mind, this paper will describe in detail applications of haptics in assembly demonstrating how user task logging can lead to the analysis of design and manufacturing tasks at a level of detail not previously possible as well as giving usable engineering outputs. The haptic 3D VR study involves the use of a Phantom and 3D system to analyse and compare this technology against real-world user performance. This work demonstrates that the detailed logging of tasks in a virtual environment gives considerable potential for understanding how virtual tasks can be mapped onto their real world equivalent as well as showing how haptic process plans can be generated in a similar manner to the conduit design and assembly planning HMD VR tool reported in PART A. The paper concludes with a view as to how the authors feel that the use of VR systems in product design and manufacturing should evolve in order to enable the industrial adoption of this technology in the future
Rights of the Public Employee under the Illinois Civil Service System: A Progression of the Law, 8 J. Marshall J. Prac. & Proc. 53 (1974)
Automated knowledge capture in 2D and 3D design environments
In Life Cycle Engineering, it is vital that the engineering knowledge for the product is captured throughout its life cycle in a formal and structured manner. This will allow the information to be referred to in the future by engineers who did not work on the original design but are wanting to understand the reasons that certain design decisions were made. In the past, attempts were made to try to capture this knowledge by having the engineer record the knowledge manually during a design session. However, this is not only time-consuming but is also disruptive to the creative process. Therefore, the research presented in this paper is concerned with capturing design knowledge automatically using a traditional 2D design environment and also an immersive 3D design environment. The design knowledge is captured by continuously and non-intrusively logging the user during a design session and then storing this output in a structured eXtensible Markup Language (XML) format. Next, the XML data is analysed and the design processes that are involved can be visualised by the automatic generation of IDEF0 diagrams. Using this captured knowledge, it forms the basis of an interactive online assistance system to aid future users who are carrying out a similar design task
Forgiveness and interpersonal skills in same-sexed friendships
Although forgiveness is a largely interpersonal process, little research has examined the relationship between forgiveness and the interpersonal skills that may be important in forgiving another for an offence. The current study addressed this issue by investigating the relationship between forgiveness and interpersonal skills in same-sexed friendships among a community sample of 210 people (mean age 38.32 years). Each participant completed the Heartland Forgiveness Scale (Thompson et al., 2005), which assesses forgiveness of self, others, and situations; and the same-sex friend version of the Interpersonal Competence Questionnaire (Buhrmester, Furman, Wittenberg, & Reis, 1988) which assesses skills in initiation, negative assertion, self-disclosure, emotional support, and conflict management. Positive correlations were found between all five interpersonal skills and the three types of forgiveness, with only the relationship between forgiveness of others and negative assertion failing to reach significance. Separate hierarchical regressions were conducted to predict each type of forgiveness, with age and gender entered at Step 1 and the interpersonal skills variables entered at Step 2. Age, initiation skills, and conflict management skills each contributed uniquely to the prediction of all three types of forgiveness. Discussion centres around the relationship between forgiveness and interpersonal skills
The puzzling case of the accreting millisecond X-ray pulsar IGR J00291+5934: flaring optical emission during quiescence
We present an optical (gri) study during quiescence of the accreting
millisecond X-ray pulsar IGR J00291+5934 performed with the 10.4m Gran
Telescopio Canarias (GTC) in August 2014. Despite the source being in
quiescence at the time of our observations, it showed a strong optical flaring
activity, more pronounced at higher frequencies (i.e. the g band). Once the
flares were subtracted, we tentatively recovered a sinusoidal modulation at the
system orbital period in all bands, even if a significant phase shift with
respect to an irradiated star, typical of accreting millisecond X-ray pulsars
is detected. We conclude that the observed flaring could be a manifestation of
the presence of an accretion disc in the system. The observed light curve
variability could be explained by the presence of a superhump, which might be
another proof of the formation of an accretion disc. In particular, the disc at
the time of our observations was probably preparing to the new outburst of the
source, that happened just a few months later, in 2015.Comment: 6 pages, 2 figures, 1 table. Accepted for publication in A&
Discovery of a new accreting millisecond X-ray pulsar in the globular cluster NGC 2808
We report on the discovery of coherent pulsations at a period of 2.9 ms from
the X-ray transient MAXI J0911-655 in the globular cluster NGC 2808. We
observed X-ray pulsations at a frequency of Hz in three different
observations of the source performed with XMM-Newton and NuSTAR during the
source outburst. This newly discovered accreting millisecond pulsar is part of
an ultra-compact binary system characterised by an orbital period of
minutes and a projected semi-major axis of lt-ms. Based on the mass
function we estimate a minimum companion mass of 0.024 M, which
assumes a neutron star mass of 1.4 M and a maximum inclination angle
of (derived from the lack of eclipses and dips in the light-curve
of the source). We find that the companion star's Roche-Lobe could either be
filled by a hot ( K) pure helium white dwarf with a 0.028
M mass (implying ) or an old (>5 Gyr) brown dwarf
with metallicity abundances between solar/sub-solar and mass ranging in the
interval 0.0650.085 M (16 < < 21). During the outburst the
broad-band energy spectra are well described by a superposition of a weak
black-body component (kT 0.5 keV) and a hard cutoff power-law with photon
index 1.7 and cut-off at a temperature kT 130 keV. Up to
the latest Swift-XRT observation performed on 2016 July 19 the source has been
observed in outburst for almost 150 days, which makes MAXI J0911-655 the second
accreting millisecond X-ray pulsar with outburst duration longer than 100 days.Comment: 7 pages, 5 figures, accepted for publication in A&
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