818 research outputs found
Discovery and partial genomic characterisation of a novel nidovirus associated with respiratory disease in wild shingleback lizards (Tiliqua rugosa)
A respiratory disease syndrome has been observed in large numbers of wild shingleback lizards (Tiliqua rugosa) admitted to wildlife care facilities in the Perth metropolitan region of Western Australia. Mortality rates are reportedly high without supportive treatment and care. Here we used next generation sequencing techniques to screen affected and unaffected individuals admitted to Kanyana Wildlife Rehabilitation Centre in Perth between April and December 2015, with the resultant discovery of a novel nidovirus significantly associated with cases of respiratory disease according to a case definition based on clinical signs. Interestingly this virus was also found in 12% of apparently healthy individuals, which may reflect testing during the incubation period or a carrier status, or it may be that this agent is not causative in the disease process. This is the first report of a nidovirus in lizards globally. In addition to detection of this virus, characterisation of a 23,832 nt segment of the viral genome revealed the presence of characteristic nidoviral genomic elements providing phylogenetic support for the inclusion of this virus in a novel genus alongside Ball Python nidovirus, within the Torovirinae sub-family of the Coronaviridae. This study highlights the importance of next generation sequencing technologies to detect and describe emerging infectious diseases in wildlife species, as well as the importance of rehabilitation centres to enhance early detection mechanisms through passive and targeted health surveillance. Further development of diagnostic tools from these findings will aid in detection and control of this agent across Australia, and potentially in wild lizard populations globally
Premature browning in cooked ground beef after modifying myoglobin
Some ground beef patties developed an
internal, brown cooked color and looked well-done
at temperatures as low as 131 ̊F, whereas
normal patties were re d to pink. The premature
brown color was not relate d to percent fat; patty
compaction; animal source and maturity; pH
(5.5 to 5.8); or concentrations of raw patty
heme and nonhemeiron, myoglobin, and total
pigment. Because oxidation-reduction potential
and total reducing activities were higher (P<.05)
and TBA numbers were lower (P<.05) in
normal than prematurely brown patties, the
brown color is apparently related to greater
patty oxidation
Comparison of the Oxidation State of Fe in Comet 81P/Wild 2 and Chondritic-Porous Interplanetary Dust Particles
The fragile structure of chondritic-porous interplanetary dust particles (CP-
IDPs) and their minimal parent-body alteration have led researchers to believe
these particles originate in comets rather than asteroids where aqueous and
thermal alteration have occurred. The solar elemental abundances and
atmospheric entry speed of CP-IDPs also suggest a cometary origin. With the
return of the Stardust samples from Jupiter-family comet 81P/Wild 2, this
hypothesis can be tested. We have measured the Fe oxidation state of 15 CP-IDPs
and 194 Stardust fragments using a synchrotron-based x-ray microprobe. We
analyzed ~300 nanograms of Wild 2 material - three orders of magnitude more
material than other analyses comparing Wild 2 and CP-IDPs. The Fe oxidation
state of these two samples of material are >2{\sigma} different: the CP-IDPs
are more oxidized than the Wild 2 grains. We conclude that comet Wild 2
contains material that formed at a lower oxygen fugacity than the parent body,
or parent bodies, of CP-IDPs. If all Jupiter-family comets are similar, they do
not appear to be consistent with the origin of CP-IDPs. However, comets that
formed from a different mix of nebular material and are more oxidized than Wild
2 could be the source of CP-IDPs.Comment: Earth and Planetary Science Letters, in pres
Improving water quality assessment and supply
Over 90 per cent of avaiable freshwater in the Arusha region of Northern Tanzania is abstracted from groundwater aquifers. The majority of this is from regolithhosted or alluvial hosted groundwater aquifers situated within 30 m of the surface. Historically this weathered mantle was assumed to protect groundwater from contamination and it is only recently that water quality has
been monitored (Coster, 1950; Wateraid, 1991). It has been demonstrated that the biogeochemical processes influencing water quality are complex (Lahermo et al., 1991; Mjengera, 1991; Smith et al., 1996; Bowell et al., 1996). The aim of this paper is to describe the relationships between water chemistry and microbiological activity in
protolith (collected below 30m, hosted by unweathered bedrock), regolith (above 30m, water hosted in the weathered
rocks and soils) and alluvial hosted groundwaters in urban (Arusha district) and rural areas (Hanang, Mbulu and Babati districts) of the Arusha region, Tanzania. An assessment is made of possible advantages and disadvantages
in utilising the various groundwaters as supplies of potable water and in potential treatment options
Beliefs and expectations about the future of personal life and future of the world in a sample of Iranian and Canadian students
This study was aimed to assess expectations about future of personal life and future of the world among a sample of Iranian and Canadian students. 60 Iranians from Tehran and Shahid Beheshti Universities in Iran and and 62 Canadians from Carleton University in Canada completed a researcher made questionnaire asking their beliefs and expectations in four areas such as personal future, generational comparison, future of the world and personal life goals. The results showed that both Iranian and Canadian participants were more optimistic about their personal future than about the future of the world but Iranians were less optimistic about the future of the world than were Canadians. Both groups expect to be richer and have a higher quality of life than their parents, and both expect their children to have a lower quality of life than their parents and to be poorer than themselves. Cultural differences were found in the importance Iranians and Canadians attach to life goals. Results and implications are discussed
New evidence for strong nonthermal effects in Tycho's supernova remnant
For the case of Tycho's supernova remnant (SNR) we present the relation
between the blast wave and contact discontinuity radii calculated within the
nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is
demonstrated that these radii are confirmed by recently published Chandra
measurements which show that the observed contact discontinuity radius is so
close to the shock radius that it can only be explained by efficient CR
acceleration which in turn makes the medium more compressible. Together with
the recently determined new value erg of the SN
explosion energy this also confirms our previous conclusion that a TeV
gamma-ray flux of erg/(cms) is to be expected from
Tycho's SNR. Chandra measurements and the HEGRA upper limit of the TeV
gamma-ray flux together limit the source distance to kpc.Comment: 5 pages, 4 figures. Accepted for publication in Astrophysics and
Space Science, Proc. of "The Multi-Messenger Approach to High-Energy
Gamma-ray Sources (Third Workshop on the Nature of Unidentified High-Energy
Sources)", Barcelona, July 4-7, 200
Enhanced stability of layered phases in parallel hard-spherocylinders due to the addition of hard spheres
There is increasing evidence that entropy can induce microphase separation in
binary fluid mixtures interacting through hard particle potentials. One such
phase consists of alternating two dimensional liquid-like layers of rods and
spheres. We study the transition from a uniform miscible state to this ordered
state using computer simulations and compare results to experiments and theory.
We conclude that (1) there is stable entropy driven microphase separation in
mixtures of parallel rods and spheres, (2) adding spheres smaller then the rod
length decreases the total volume fraction needed for the formation of a
layered phase, therefore small spheres effectively stabilize the layered phase;
the opposite is true for large spheres and (3) the degree of this stabilization
increases with increasing rod length.Comment: 11 pages, 9 figures. Submitted to Phys. Rev. E. See related website
http://www.elsie.brandeis.ed
Tunable multi-wavelength third-harmonic generation using exposed-core microstructured optical fiber
We demonstrate that exposed-core microstructured optical fibers offer multiple degrees of freedom for tailoring third-harmonic generation through the core diameter, input polarization, and nanofilm deposition. Varying these parameters allows control of the phase-matching position between an infrared pump wavelength and the generated visible wavelengths. In this Letter, we show how increasing the core diameter over previous experiments (2.57 μm compared to 1.85 μm) allows the generation of multiple wavelengths, which can be further controlled by rotating the input pump polarization and the deposition of dielectric nanofilms. This can lead to highly tailorable light sources for applications such as spectroscopy or nonlinear microscopy.Stephen C. Warren-Smith, Kay Schaarschmidt, Mario Chemnitz, Erik P. Schartner, Henrik Schneidewind, Heike Ebendorff-Heidepriem and Markus A. Schmid
Understanding hadronic gamma-ray emission from supernova remnants
We aim to test the plausibility of a theoretical framework in which the
gamma-ray emission detected from supernova remnants may be of hadronic origin,
i.e., due to the decay of neutral pions produced in nuclear collisions
involving relativistic nuclei. In particular, we investigate the effects
induced by magnetic field amplification on the expected particle spectra,
outlining a phenomenological scenario consistent with both the underlying
Physics and the larger and larger amount of observational data provided by the
present generation of gamma experiments, which seem to indicate rather steep
spectra for the accelerated particles. In addition, in order to study to study
how pre-supernova winds might affect the expected emission in this class of
sources, the time-dependent gamma-ray luminosity of a remnant with a massive
progenitor is worked out. Solid points and limitations of the proposed scenario
are finally discussed in a critical way.Comment: 30 pages, 5 figures; Several comments, references and a figure added.
Some typos correcte
Simulated Optimisation of Disordered Structures with negative Poisson’s ratios
Copyright © 2009 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Mechanics of Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Mechanics of Materials, Vol. 41 Issue 8 (2009). DOI: 10.1016/j.mechmat.2009.04.008Two-dimensional regular theoretical units that give a negative Poisson’s ratio (NPR) are well documented and well understood. Predicted mechanical properties resulting from these models are reasonably accurate in two dimensions but fall down when used for heterogeneous real-world materials. Manufacturing processes are seldom perfect and some measure of heterogeneity is therefore required to account for the deviations from the regular unit cells in this real-life situation. Analysis of heterogeneous materials in three dimensions is a formidable problem; we must first understand heterogeneity in two dimensions. This paper approaches the problem of finding a link between heterogeneous networks and its material properties from a new angle. Existing optimisation tools are used to create random two-dimensional topologies that display NPR, and the disorder in the structure and its relationship with NPR is investigated
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