320 research outputs found
Visual Climate Change Communication: From Iconography To Locally Framed 3D Visualization
Climate change is an urgent problem with implications registered not only globally, but also on national and local scales. It is a particularly challenging case of environmental communication because its main cause, greenhouse gas emissions, is invisible. The predominant approach of making climate change visible is the use of iconic, often affective, imagery. Literature on the iconography of climate change shows that global iconic motifs, such as polar bears, have contributed to a public perception of the problem as spatially and temporally remote. This paper proposes an alternative approach to global climate change icons by focusing on recognizable representations of local impacts within an interactive game environment. This approach was implemented and tested in a research project based on the municipality of Delta, British Columbia. A major outcome of the research is Future Delta, an interactive educational game featuring 3D visualizations and simulation tools for climate change adaptation and mitigation future scenarios. The empirical evaluation is based on quantitative pre/post-game play questionnaires with 18 students and 10 qualitative expert interviews. The findings support the assumption that interactive 3D imagery is effective in communicating climate change. The quantitative post-questionnaires particularly highlight a shift in support of more local responsibility
Porphyrins as building blocks for single-molecule devices
Direct measurement of single-molecule electrical transparency by break junction experiments has become a major field of research over the two last decades. This review specifically and comprehensively highlights the use of porphyrins as molecular components and discusses their potential use for the construction of future devices. Throughout the review, the features provided by porphyrins, such as low level misalignments and very low attenuation factors, are shown with numerous examples, illustrating the potential and limitations of these molecular junctions, as well as differences emerging from applied integration/investigation techniques
Charge transport through a single molecule of trans-1-bis-diazofluorene [60]fullerene
Fullerenes have attracted interest for their possible applications in various
electronic, biological, and optoelectronic devices. However, for efficient use
in such devices, a suitable anchoring group has to be employed that forms
well-defined and stable contacts with the electrodes. In this work, we propose
a novel fullerene tetramalonate derivate functionalized with trans-1
4,5-diazafluorene anchoring groups. The conductance of single-molecule
junctions, investigated in two different setups with the mechanically
controlled break junction technique, reveals the formation of molecular
junctions at three conductance levels. We attribute the conductance peaks to
three binding modes of the anchoring groups to the gold electrodes. Density
functional theory calculations confirm the existence of multiple binding
configurations and calculated transmission functions are consistent with
experimentally determined conductance values.Comment: 22 pages, 6 figure
T-Cell Subsets in Rheumatoid Arthritis Patients on Long-Term Anti-TNF or IL-6 Receptor Blocker Therapy
Data on the impact of biological therapies on the T-cell phenotype in rheumatoid arthritis are limited. Here, we prospectively measured the percentages of 15 circulating T-cell subtypes using flow cytometry. We obtained transversal and longitudinal data in 30 anti-TNF responders, 19 secondary anti-TNF nonresponders, and 43 IL-6R antagonist responders, before, 8 weeks and at least 6 months after biological therapy. Untreated RA patients and healthy controls were also included. The important findings are the following: ( 1) the proportion of regulatory T-cells (Tregs) which are decreased in untreated RA patients becomes normal in all long-term-treated groups; ( 2) in anti-TNF responders as well as in nonresponders, the frequencies of naive CD4+ and CD8+ cells are lower, whereas those of proinflammatory Th1, Th2, and Th17 cells and HLA-DR+-activated cells are higher than those in untreated RA or healthy controls; ( 3) in IL-6R responders, Th1 proportion is decreased, while that of Th2 and Th17 is increased as compared to that in anti-TNF-treated patients and controls; ( 4) pending confirmation, a CD4CD69 ratio <2.43 at baseline, could be useful to predict a good therapeutic response to anti-TNF therapy. This study provides comprehensive information regarding the long-term impacts of those biological therapies on the ecotaxis of T-cells in RA
Unravelling the conductance path through single-porphyrin junctions
Porphyrin derivatives are key components in natural machinery enabling us to store sunlight as chemical energy. In spite of their prominent role in cascades separating electrical charges and their potential as sensitizers in molecular devices
Superconductivity, phase fluctuations and the c-axis conductivity of bilayer high temperature superconductors
We present a theory of the interplane conductivity of bilayer high
temperature superconductors, focusing on the effect of quantal and thermal
fluctuations on the oscillator strengths of the superfluid stiffness and the
bilayer plasmon. We find that the opening of the superconducting gap and
establishment of superconducting phase coherence each lead to redistribution of
spectral weight over wide energy scales. The factor-of-two relation between the
superfluid stiffness and the change below in the oscillator strength of
the absorptive part of the conductivity previously derived for single-layer
systems, is found to be substantially modified in bilayer systems.Comment: 11 pages, 14 figure
Correlation between the Josephson coupling energy and the condensation energy in bilayer cuprate superconductors
We review some previous studies concerning the intra-bilayer Josephson
plasmons and present new ellipsometric data of the c-axis infrared response of
almost optimally doped Bi_{2}Sr_{2}CaCu_{2}O_{8}. The c-axis conductivity of
this compound exhibits the same kind of anomalies as that of underdoped
YBa_{2}Cu_{3}O_{7-delta}. We analyze these anomalies in detail and show that
they can be explained within a model involving the intra-bilayer Josephson
effect and variations of the electric field inside the unit cell. The Josephson
coupling energies of different bilayer compounds obtained from the optical data
are compared with the condensation energies and it is shown that there is a
reasonable agreement between the values of the two quantities. We argue that
the Josephson coupling energy, as determined by the frequency of the
intra-bilayer Josephson plasmon, represents a reasonable estimate of the change
of the effective c-axis kinetic energy upon entering the superconducting state.
It is further explained that this is not the case for the estimate based on the
use of the simplest ``tight-binding'' sum rule. We discuss possible
interpretations of the remarkable agreement between the Josephson coupling
energies and the condensation energies. The most plausible interpretation is
that the interlayer tunneling of the Cooper pairs provides the dominant
contribution to the condensation energy of the bilayer compounds; in other
words that the condensation energy of these compounds can be accounted for by
the interlayer tunneling theory. We suggest an extension of this theory, which
may also explain the high values of T_{c} in the single layer compounds
Tl_{2}Ba_{2}CuO_{6} and HgBa_{2}CuO_{4}, and we make several experimentally
verifiable predictions.Comment: 16 pages (including Tables) and 7 figures; accepted for publication
in Physical Review
Differential requirements for actin during yeast and mammalian endocytosis
Key features of clathrin-mediated endocytosis have been conserved across evolution. However, endocytosis in Saccharomyces cerevisiae is completely dependent on a functional actin cytoskeleton, whereas actin appears to be less critical in mammalian cell endocytosis. We reveal that the fundamental requirement for actin in the early stages of yeast endocytosis is to provide a strong framework to support the force generation needed to direct the invaginating plasma membrane into the cell against turgor pressure. By providing osmotic support, pressure differences across the plasma membrane were removed and this reduced the requirement for actin-bundling proteins in normal endocytosis. Conversely, increased turgor pressure in specific yeast mutants correlated with a decreased rate of endocytic patch invagination
Penetration of Josephson vortices and measurement of the c-axis penetration depth in : Interplay of Josephson coupling, surface barrier and defects
The first penetration field H_{J}(T) of Josephson vortices is measured
through the onset of microwave absorption in the locked state, in slightly
overdoped single crystals (T_{c} ~ 84
K). The magnitude of H_{J}(T) is too large to be accounted for by the first
thermodynamic critical field H_{c1}(T). We discuss the possibility of a
Bean-Livingston barrier, also supported by irreversible behavior upon flux
exit, and the role of defects, which relates H_{J}(T) to the c-axis penetration
depth . The temperature dependence of the latter, determined by
a cavity perturbation technique and a theoretical estimate of the
defect-limited penetration field are used to deduce from H_{J}(T) the absolute
value of .Comment: 9 pages, 6 figure
Decoupling of a Current-Biased Intrinsic Josephson Junction from its Environment
We have observed a dissipative phase diffusion branch in arrays of hysteretic
high-Tc intrinsic Josephson junctions. By comparing the data with a thermal
activation model we extract the impedance seen by the junction in which phase
diffusion is occurring. At the plasma frequency this junction is isolated from
its environment and it sees its own large (~ kilo Ohm) impedance. Our results
suggest that stacks of Josephson junctions may be used for isolation purposes
in the development of a solid state quantum computer
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