8,404 research outputs found
Anchoring effects in the development of false childhood memories
When people receive descriptions or doctored photos of events that never happened, they often come to remember those events. But if people receive both a description and a doctored photo, does the order in which they receive the information matter? We asked people to consider a description and a doctored photograph of a childhood hot air balloon ride, and we varied which medium they saw first. People who saw a description first reported more false images and memories than people who saw a photo first, a result that fits with an anchoring account of false childhood memories
Estimation of Delamination Crack Depth Using Passive Thermography
Passive thermography is used to monitor small increases in temperature resulting from delamination damage formation in a composite hat-stiffened panel during quasi-static loading. The heating is composed of two heat generation components. The first component is an instantaneous response due to a strain release during quasi-static loading. The second component is mechanical heating, at the interface of failure, due to fracture damage. This second component produces a transient rise in temperature that is a function of the damage depth and thermal diffusivity. The first component defines the thermal start time for the transient response. A one-dimensional thermal model is used to determine the damage depth. The results are compared to ultrasonic and X-ray CT data. The advantages and limitations of the thermal technique for damage depth detection are discussed
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Modelling fixed plant and algal dynamics in rivers: an application to the River Frome
The development of eutrophication in river systems is poorly understood given the complex relationship between fixed plants, algae, hydrodynamics, water chemistry and solar radiation. However there is a pressing need to understand the relationship between the ecological status of
rivers and the controlling environmental factors to help the reasoned implementation of the Water Framework Directive and Catchment Sensitive Farming in the UK. This research aims to create a dynamic, process-based, mathematical in-stream model to simulate the growth and competition of different vegetation types (macrophytes, phytoplankton and benthic algae) in rivers. The model,
applied to the River Frome (Dorset, UK), captured well the seasonality of simulated vegetation types (suspended algae, macrophytes, epiphytes, sediment biofilm). Macrophyte results showed that local knowledge is important for explaining unusual changes in biomass. Fixed algae simulations indicated the need for the more detailed representation of various herbivorous grazer groups,
however this would increase the model complexity, the number of model parameters and the required observation data to better define the model. The model results also highlighted that simulating only phytoplankton is insufficient in river systems, because the majority of the suspended algae have benthic origin in short retention time rivers. Therefore, there is a need for modelling tools that link the benthic and free-floating habitats
Investigating the origin of cyclical wind variability in hot, massive stars - II. Hydrodynamical simulations of co-rotating interaction regions using realistic spot parameters for the O giant Persei
OB stars exhibit various types of spectral variability historically
associated with wind structures, including the apparently ubiquitous discrete
absorption components (DACs). These features have been proposed to be caused
either by magnetic fields or non-radial pulsations. In this second paper of
this series, we revisit the canonical phenomenological hydrodynamical modelling
used to explain the formation of DACs by taking into account modern
observations and more realistic theoretical predictions. Using constraints on
putative bright spots located on the surface of the O giant Persei
derived from high precision space-based broadband optical photometry obtained
with the Microvariability and Oscillations of STars (MOST) space telescope, we
generate two-dimensional hydrodynamical simulations of co-rotating interaction
regions in its wind. We then compute synthetic ultraviolet (UV) resonance line
profiles using Sobolev Exact Integration and compare them with historical
timeseries obtained by the International Ultraviolet Explorer (IUE) to evaluate
if the observed behaviour of Persei's DACs is reproduced. Testing three
different models of spot size and strength, we find that the classical pattern
of variability can be successfully reproduced for two of them: the model with
the smallest spots yields absorption features that are incompatible with
observations. Furthermore, we test the effect of the radial dependence of
ionization levels on line driving, but cannot conclusively assess the
importance of this factor. In conclusion, this study self-consistently links
optical photometry and UV spectroscopy, paving the way to a better
understanding of cyclical wind variability in massive stars in the context of
the bright spot paradigm.Comment: 16 pages, 10 figures, accepted for publication by MNRA
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