2,424 research outputs found
Reciprocity as deliberative capacity: lessons from a citizens deliberation on carbon pricing mechanisms in Australia
Australia has seen a deep division in opinion in search of a carbon pricing mechanism. While concepts of carbon taxation and emission trading have comparable public support, climate scepticism is influencing the debates in political and public spheres in downplaying the need for carbon pricing. Public deliberation is a possible engagement option to address the conflict inherent in climate policy preferences. This research explores the way that a deliberative forum involving twenty-four Australians promoted effective communication between participants through which conflict between policy preferences became more tangible. While the forum did not eliminate disagreement in preferences in the choice of carbon pricing mechanisms, participants reached consensus on fundamental principles such as the need for trusted sources of information, trusted governance procedures, and transparent accountability by appropriate institutions. Shared political expectations encouraged dialogue and cooperation in discussions by enhancing reciprocal understanding. Two sceptical participants who originally had strong opinions different from the rest of the group managed to find common ground. Public deliberative forums that are conducive to reciprocal communication are able to provide a mechanism for joint problem-solving processes that are less adversarial and more responsive to the range of people\u27s preferences. Keywords: public deliberation, consensus, emission trading, carbon tax, deliberative democracy, Australi
Experimental and Computational Analysis of Polyglutamine-Mediated Cytotoxicity
Expanded polyglutamine (polyQ) proteins are known to be the causative agents of a number of human neurodegenerative diseases but the molecular basis of their cytoxicity is still poorly understood. PolyQ tracts may impede the activity of the proteasome, and evidence from single cell imaging suggests that the sequestration of polyQ into inclusion bodies can reduce the proteasomal burden and promote cell survival, at least in the short term. The presence of misfolded protein also leads to activation of stress kinases such as p38MAPK, which can be cytotoxic. The relationships of these systems are not well understood. We have used fluorescent reporter systems imaged in living cells, and stochastic computer modeling to explore the relationships of polyQ, p38MAPK activation, generation of reactive oxygen species (ROS), proteasome inhibition, and inclusion body formation. In cells expressing a polyQ protein inclusion, body formation was preceded by proteasome inhibition but cytotoxicity was greatly reduced by administration of a p38MAPK inhibitor. Computer simulations suggested that without the generation of ROS, the proteasome inhibition and activation of p38MAPK would have significantly reduced toxicity. Our data suggest a vicious cycle of stress kinase activation and proteasome inhibition that is ultimately lethal to cells. There was close agreement between experimental data and the predictions of a stochastic computer model, supporting a central role for proteasome inhibition and p38MAPK activation in inclusion body formation and ROS-mediated cell death
Pressure coefficients of Raman modes of carbon nanotubes resolved by chirality: Environmental effect on graphene sheet
Studies of the mechanical properties of single-walled carbon nanotubes are
hindered by the availability only of ensembles of tubes with a range of
diameters. Tunable Raman excitation spectroscopy picks out identifiable tubes.
Under high pressure, the radial breathing mode shows a strong environmental
effect shown here to be largely independent of the nature of the environment .
For the G-mode, the pressure coefficient varies with diameter consistent with
the thick-wall tube model. However, results show an unexpectedly strong
environmental effect on the pressure coefficients. Reappraisal of data for
graphene and graphite gives the G-mode Grueuneisen parameter gamma = 1.34 and
the shear deformation parameter beta = 1.34.Comment: Submitted to Physical Review
Analysis of the shearing instability in nonlinear convection and magnetoconvection
Numerical experiments on two-dimensional convection with or without a vertical magnetic field reveal a bewildering variety of periodic and aperiodic oscillations. Steady rolls can develop a shearing instability, in which rolls turning over in one direction grow at the expense of rolls turning over in the other, resulting in a net shear across the layer. As the temperature difference across the fluid is increased, two-dimensional pulsating waves occur, in which the direction of shear alternates. We analyse the nonlinear dynamics of this behaviour by first constructing appropriate low-order sets of ordinary differential equations, which show the same behaviour, and then analysing the global bifurcations that lead to these oscillations by constructing one-dimensional return maps. We compare the behaviour of the partial differential equations, the models and the maps in systematic two-parameter studies of both the magnetic and the non-magnetic cases, emphasising how the symmetries of periodic solutions change as a result of global bifurcations. Much of the interesting behaviour is associated with a discontinuous change in the leading direction of a fixed point at a global bifurcation; this change occurs when the magnetic field is introduced
Dynamics of charged fluids and 1/L perturbation expansions
Some features of the calculation of fluid dynamo systems in
magnetohydrodynamics are studied. In the coupled set of the ordinary linear
differential equations for the spherically symmetric dynamos, the
problem represented by the presence of the mixed (Robin) boundary conditions is
addressed and a new treatment for it is proposed. The perturbation formalism of
large expansions is shown applicable and its main technical steps are
outlined.Comment: 16 p
Stein's Method and Characters of Compact Lie Groups
Stein's method is used to study the trace of a random element from a compact
Lie group or symmetric space. Central limit theorems are proved using very
little information: character values on a single element and the decomposition
of the square of the trace into irreducible components. This is illustrated for
Lie groups of classical type and Dyson's circular ensembles. The approach in
this paper will be useful for the study of higher dimensional characters, where
normal approximations need not hold.Comment: 22 pages; same results, but more efficient exposition in Section 3.
Decoding the Regulatory Landscape of Ageing in Musculoskeletal Engineered Tissues Using Genome-Wide DNA Methylation and RNASeq
Mesenchymal stem cells (MSC) are capable of multipotent differentiation into connective tissues and as such are an attractive source for autologous cell-based regenerative medicine and tissue engineering. Epigenetic mechanisms, like DNA methylation, contribute to the changes in gene expression in ageing. However there was a lack of sufficient knowledge of the role that differential methylation plays during chondrogenic, osteogenic and tenogenic differentiation from ageing MSCs. This study undertook genome level determination of the effects of DNA methylation on expression in engineered tissues from chronologically aged MSCs. We compiled unique DNA methylation signatures from chondrogenic, osteogenic, and tenogenic engineered tissues derived from young; n = 4 (21.8 years ± 2.4 SD) and old; n = 4 (65.5 years±8.3SD) human MSCs donors using the Illumina HumanMethylation 450 Beadchip arrays and compared these to gene expression by RNA sequencing. Unique and common signatures of global DNA methylation were identified. There were 201, 67 and 32 chondrogenic, osteogenic and tenogenic age-related DE protein-coding genes respectively. Findings inferred the nature of the transcript networks was predominantly for ‘cell death and survival’, ‘cell morphology’, and ‘cell growth and proliferation’. Further studies are required to validate if this gene expression effect translates to cell events. Alternative splicing (AS) was dysregulated in ageing with 119, 21 and 9 differential splicing events identified in chondrogenic, osteogenic and tenogenic respectively, and enrichment in genes associated principally with metabolic processes. Gene ontology analysis of differentially methylated loci indicated age-related enrichment for all engineered tissue types in ‘skeletal system morphogenesis’, ‘regulation of cell proliferation’ and ‘regulation of transcription’ suggesting that dynamic epigenetic modifications may occur in genes associated with shared and distinct pathways dependent upon engineered tissue type. An altered phenotype in engineered tissues was observed with ageing at numerous levels. These changes represent novel insights into the ageing process, with implications for stem cell therapies in older patients. In addition we have identified a number of tissue-dependant pathways, which warrant further studies
Square patterns in Rayleigh-Benard convection with rotation about a vertical axis
We present experimental results for Rayleigh-Benard convection with rotation
about a vertical axis at dimensionless rotation rates in the range 0 to 250 and
upto 20% above the onset. Critical Rayleigh numbers and wavenumbers agree with
predictions of linear stability analysis. For rotation rates greater than 70
and close to onset, the patterns are cellular with local four-fold coordination
and differ from the theoretically expected Kuppers-Lortz unstable state. Stable
as well as intermittent defect-free square lattices exist over certain
parameter ranges. Over other ranges defects dynamically disrupt the lattice but
cellular flow and local four-fold coordination is maintained.Comment: ReVTeX, 4 pages, 7 eps figures include
ASCA X-ray source catalogue in the Galactic Center region
The ASCA satellite made 107 pointing observations on a 5 x 5 deg^2 region
around the center of our Milky Way Galaxy (the Galactic Center) from 1993 to
1999. In the X-ray images of the 0.7--3 keV or 3--10 keV bands, we found 52
point sources and a dozen diffuse sources. All the point sources are uniformly
fitted with an absorbed power-law model. For selected bright sources, Sgr A*,
AX J1745.6-2901, A 1742-294, SLX 1744-300, GRO J1744-28, SLX 1737-282, GRS
1734-292, AX J1749.2-2725, KS 1741-293, GRS 1741.9-2853, and an unusual flare
source XTE J1739-302, we present further detailed spectral and timing analyses,
and discuss their nature.
The dozen extended X-ray sources comprise radio supernova remnants, giant
molecular clouds, and some new discoveries. Most show emission lines from
either highly ionized atoms or low-ionized irons.
The X-ray spectra were fitted with either a thin thermal or power-law model.
This paper summarizes the results and provides the ASCA X-ray source catalogue
in the Galactic Center region.Comment: 33 pages, 8 figures, Accepted for publication in ApJS, also found in
http://www.star.le.ac.uk/~mas/research/paper/#Sakano2001apj
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