4,001 research outputs found
Light and neutron scattering studies of the OH stretching band in liquid and supercritical water
The hydrogen projected OH stretching density of states has been determined by an inelastic neutron scattering experiment in liquid and supercritical water, The results, compared with new measurements of the isotropic Raman spectra at the same state conditions, support the interpretation of the Raman spectra in terms of superposition of the allowed nu(1) band with the overtone of the nu(2) band. (C) 1998 American Institute of Physics
Effects of Prediction Feedback in Multi-Route Intelligent Traffic Systems
We first study the influence of an efficient feedback strategy named
prediction feedback strategy (PFS) based on a multi-route scenario in which
dynamic information can be generated and displayed on the board to guide road
users to make a choice. In this scenario, our model incorporates the effects of
adaptability into the cellular automaton models of traffic flow. Simulation
results adopting this optimal information feedback strategy have demonstrated
high efficiency in controlling spatial distribution of traffic patterns
compared with the other three information feedback strategies, i.e., vehicle
number and flux. At the end of this paper, we also discuss in what situation
PFS will become invalid in multi-route systems.Comment: 15 pages, 15 figures, Physica A (2010),
doi:10.1016/j.physa.2010.02.03
Prediction feedback in intelligent traffic systems
The optimal information feedback has a significant effect on many
socioeconomic systems like stock market and traffic systems aiming to make full
use of resources. In this paper, we studied dynamics of traffic flow with
real-time information provided and the influence of a feedback strategy named
prediction feedback strategy is introduced, based on a two-route scenario in
which dynamic information can be generated and displayed on the board to guide
road users to make a choice. Our model incorporates the effects of adaptability
into the cellular automaton models of traffic flow and simulation results
adopting this optimal information feedback strategy have demonstrated high
efficiency in controlling spatial distribution of traffic patterns compared
with the other three information feedback strategies, i.e., vehicle number and
flux.Comment: 14 pages, 15 figure
Establishing comprehensive oral assessments for children with safeguarding concerns.
The dental profession is well placed to contribute important information in child protection cases but no previous research has been reported that assesses the volume or impact of this information. Comprehensive oral assessment clinics were introduced and established as an integral part of comprehensive medical assessments for children with welfare concerns in Greater Glasgow and Clyde. An assessment protocol and standardised paperwork for comprehensive oral assessments were developed to enhance information sharing and patient access to appropriate care. Two cases are presented and discussed to demonstrate the value of dental input
Silicon Mie Resonators for Highly Directional Light Emission from monolayer MoS2
Controlling light emission from quantum emitters has important applications
ranging from solid-state lighting and displays to nanoscale single-photon
sources. Optical antennas have emerged as promising tools to achieve such
control right at the location of the emitter, without the need for bulky,
external optics. Semiconductor nanoantennas are particularly practical for this
purpose because simple geometries, such as wires and spheres, support multiple,
degenerate optical resonances. Here, we start by modifying Mie scattering
theory developed for plane wave illumination to describe scattering of dipole
emission. We then use this theory and experiments to demonstrate several
pathways to achieve control over the directionality, polarization state, and
spectral emission that rely on a coherent coupling of an emitting dipole to
optical resonances of a Si nanowire. A forward-to-backward ratio of 20 was
demonstrated for the electric dipole emission at 680 nm from a monolayer MoS2
by optically coupling it to a Si nanowire
Networked buffering: a basic mechanism for distributed robustness in complex adaptive systems
A generic mechanism - networked buffering - is proposed for the generation of robust traits in complex systems. It requires two basic conditions to be satisfied: 1) agents are versatile enough to perform more than one single functional role within a system and 2) agents are degenerate, i.e. there exists partial overlap in the functional capabilities of agents. Given these prerequisites, degenerate systems can readily produce a distributed systemic response to local perturbations. Reciprocally, excess resources related to a single function can indirectly support multiple unrelated functions within a degenerate system. In models of genome:proteome mappings for which localized decision-making and modularity of genetic functions are assumed, we verify that such distributed compensatory effects cause enhanced robustness of system traits. The conditions needed for networked buffering to occur are neither demanding nor rare, supporting the conjecture that degeneracy may fundamentally underpin distributed robustness within several biotic and abiotic systems. For instance, networked buffering offers new insights into systems engineering and planning activities that occur under high uncertainty. It may also help explain recent developments in understanding the origins of resilience within complex ecosystems. \ud
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Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient
We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide
The Effects of Gas on Morphological Transformation in Mergers: Implications for Bulge and Disk Demographics
Transformation of disks into spheroids via mergers is a well-accepted element
of galaxy formation models. However, recent simulations have shown that bulge
formation is suppressed in increasingly gas-rich mergers. We investigate the
global implications of these results in a cosmological framework, using
independent approaches: empirical halo-occupation models (where galaxies are
populated in halos according to observations) and semi-analytic models. In
both, ignoring the effects of gas in mergers leads to the over-production of
spheroids: low and intermediate-mass galaxies are predicted to be
bulge-dominated (B/T~0.5 at <10^10 M_sun), with almost no bulgeless systems),
even if they have avoided major mergers. Including the different physical
behavior of gas in mergers immediately leads to a dramatic change: bulge
formation is suppressed in low-mass galaxies, observed to be gas-rich (giving
B/T~0.1 at <10^10 M_sun, with a number of bulgeless galaxies in good agreement
with observations). Simulations and analytic models which neglect the
similarity-breaking behavior of gas have difficulty reproducing the strong
observed morphology-mass relation. However, the observed dependence of gas
fractions on mass, combined with suppression of bulge formation in gas-rich
mergers, naturally leads to the observed trends. Discrepancies between
observations and models that ignore the role of gas increase with redshift; in
models that treat gas properly, galaxies are predicted to be less
bulge-dominated at high redshifts, in agreement with the observations. We
discuss implications for the global bulge mass density and future observational
tests.Comment: 14 pages, 11 figures, accepted to MNRAS (matched published version).
A routine to return the galaxy merger rates discussed here is available at
http://www.cfa.harvard.edu/~phopkins/Site/mergercalc.htm
TRY plant trait database - enhanced coverage and open access
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
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