Leisure Travel Market Potential for a High Speed Civil Transport

A second-generation supersonic airliner, known as the High Speed Civil Transport (HSCT), is now on the drawing boards to replace mid-life Concorde and to expand into longer-range markets beginning early next century. Passenger interviews conducted in May 1994 at Schiphol Airport in Amsterdam, Netherlands, evaluated the largely unknown habits and attitudes of specifically leisure travelers, expected to be a significant segment of a successful HSCT market. In addition to establishing value of time, ticket purchasing habits, and general airline traveling attitudes of leisure travelers, results also indicate that HSCT marketers may have to dispel lingering Concorde stereotypes to win public acceptance

Laboratory measurements of forward and backward scattering of laser beams in water droplet clouds

Many aspects of the forward and backward scattering in dense water droplet clouds were studied using a laboratory scattering facility. This system is configured in a lidar geometry to facilitate comparison of the laboratory results to current lidar oriented theory and measurements. The backscatter measurements are supported with simultaneous measurements of the optical density, mass concentration, and droplet size distribution of the clouds. Measurements of the extinction and backscatter coefficients at several important laser wavelength have provided data on the relationship between these quantities for laboratory clouds at .633, 1.06, and 10.6 microns. The polarization characteristics of the backscatter of 1.06 microns were studied using several different types of clouds. More recently, the laboratory facility was modified to allow range-resolved backscatter measurements at 1.06 microns. Clouds made up of 3 layers, each with its own density, can be constructed. This allows the study of the effect of cloud inhomogeneity on the forward and backscatter

Considerations for Atmospheric Measurements with Small Unmanned Aircraft Systems

This paper discusses results of the CLOUD-MAP(Collaboration Leading Operational UAS Development for Meteorology and Atmospheric Physics) project dedicated to developing, fielding, and evaluating integrated small unmanned aircraft systems (sUAS) for enhanced atmospheric physics measurements. The project team includes atmospheric scientists, meteorologists, engineers, computer scientists, geographers, and chemists necessary to evaluate the needs and develop the advanced sensing and imaging, robust autonomous navigation, enhanced data communication, and data management capabilities required to use sUAS in atmospheric physics. Annual integrated evaluation of the systems in coordinated field tests are being used to validate sensor performance while integrated into various sUAS platforms. This paper focuses on aspects related to atmospheric sampling of thermodynamic parameters with sUAS, specifically sensor integration and calibration/validation, particularly as it relates to boundary layer profiling. Validation of sensor output is performed by comparing measurements with known values, including instrumented towers, radiosondes, and other validated sUAS platforms. Experiments to determine the impact of sensor location and vehicle operation have been performed, with sensor aspiration a major factor. Measurements are robust provided that instrument packages are properly mounted in locations that provide adequate air flow and proper solar shielding

Theory of Coherent Time-dependent Transport in One-dimensional Multiband Semiconductor Superlattices

We present an analytical study of one-dimensional semiconductor superlattices in external electric fields, which may be time-dependent. A number of general results for the (quasi)energies and eigenstates are derived. An equation of motion for the density matrix is obtained for a two-band model, and the properties of the solutions are analyzed. An expression for the current is obtained. Finally, Zener-tunneling in a two-band tight-binding model is considered. The present work gives the background and an extension of the theoretical framework underlying our recent Letter [J. Rotvig {\it et al.}, Phys. Rev. Lett. {\bf 74}, 1831 (1995)], where a set of numerical simulations were presented.Comment: 15 pages, Revtex 3.0, uses epsf, 2 ps figures attache

Local light-ray rotation

We present a sheet structure that rotates the local ray direction through an arbitrary angle around the sheet normal. The sheet structure consists of two parallel Dove-prism sheets, each of which flips one component of the local direction of transmitted light rays. Together, the two sheets rotate transmitted light rays around the sheet normal. We show that the direction under which a point light source is seen is given by a Mobius transform. We illustrate some of the properties with movies calculated by ray-tracing software.Comment: 9 pages, 6 figure

Targeted mutation of barley (1,3;1,4)-β-glucan synthases reveals complex relationships between the storage and cell wall polysaccharide content

Barley (Hordeum vulgare L) grain is comparatively rich in (1,3;1,4)-β-glucan, a source of fermentable dietary fibre that protects against various human health conditions. However, low grain (1,3;1,4)-β-glucan content is preferred for brewing and distilling. We took a reverse genetics approach, using CRISPR/Cas9 to generate mutations in members of the Cellulose synthase-like (Csl) gene superfamily that encode known (HvCslF6 and HvCslH1) and putative (HvCslF3 and HvCslF9) (1,3;1,4)-β-glucan synthases. Resultant mutations ranged from single amino acid (aa) substitutions to frameshift mutations causing premature stop codons, and led to specific differences in grain morphology, composition and (1,3;1,4)-β-glucan content. (1,3;1,4)-β-Glucan was absent in the grain of cslf6 knockout lines, whereas cslf9 knockout lines had similar (1,3;1,4)-β-glucan content to wild-type (WT). However, cslf9 mutants showed changes in the abundance of other cell-wall-related monosaccharides compared with WT. Thousand grain weight (TGW), grain length, width and surface area were altered in cslf6 knockouts, and to a lesser extent TGW in cslf9 knockouts. cslf3 and cslh1 mutants had no effect on grain (1,3;1,4)-β-glucan content. Our data indicate that multiple members of the CslF/H family fulfil important functions during grain development but, with the exception of HvCslF6, do not impact the abundance of (1,3;1,4)-β-glucan in mature grain.</p

Developing Dementia-Friendly Tourism Destinations: An Exploratory Analysis

Dementia is emerging as a global issue. Increases in life expectancy create an older population structure with accompanying health needs but also high lifestyle expectations. For example existing generations have come to expect to be able to participate in leisure and tourism activities in later life, which can be constrained by the onset of dementia. Leading healthy lifestyles and engaging in tourism activities are viewed as fundamental to remaining active and contributing to slowing the progress of dementia. This study is the first to examine the challenges and implications of the growing scale of dementia and the business opportunities this may create for destinations wishing to achieve dementia-friendly status. The paper reports results from an initial scoping study with tourism businesses in a coastal resort in the United Kingdom with such ambitions to assess the nature of the issues that arose from a series of face-to-face interviews

Rich Pickings Near Large Communal Roosts Favor ‘Gang’ Foraging by Juvenile Common Ravens, Corvus corax

Ravens (Corvus corax) feed primarily on rich but ephemeral carcasses of large animals, which are usually defended by territorial pairs of adults. Non-breeding juveniles forage socially and aggregate in communal winter roosts, and these appear to function as ‘information centers’ regarding the location of the rare food bonanzas: individuals search independently of one another and pool their effort by recruiting each other at roosts. However, at a large raven roost in Newborough on Anglesey, North Wales, some juveniles have been observed recently to forage in ‘gangs’ and to roost separately from other birds. Here we adapt a general model of juvenile common raven foraging behavior where, in addition to the typical co-operative foraging strategy, such gang foraging behavior could be evolutionarily stable near winter raven roosts. We refocus the model on the conditions under which this newly documented, yet theoretically anticipated, gang-based foraging has been observed. In the process, we show formally how the trade off between search efficiency and social opportunity can account for the existence of the alternative social foraging tactics that have been observed in this species. This work serves to highlight a number of fruitful avenues for future research, both from a theoretical and empirical perspective

Behavioural syndrome in a solitary predator is independent of body size and growth rate.

Models explaining behavioural syndromes often focus on state-dependency, linking behavioural variation to individual differences in other phenotypic features. Empirical studies are, however, rare. Here, we tested for a size and growth-dependent stable behavioural syndrome in the juvenile-stages of a solitary apex predator (pike, Esox lucius), shown as repeatable foraging behaviour across risk. Pike swimming activity, latency to prey attack, number of successful and unsuccessful prey attacks was measured during the presence/absence of visual contact with a competitor or predator. Foraging behaviour across risks was considered an appropriate indicator of boldness in this solitary predator where a trade-off between foraging behaviour and threat avoidance has been reported. Support was found for a behavioural syndrome, where the rank order differences in the foraging behaviour between individuals were maintained across time and risk situation. However, individual behaviour was independent of body size and growth in conditions of high food availability, showing no evidence to support the state-dependent personality hypothesis. The importance of a combination of spatial and temporal environmental variation for generating growth differences is highlighted

Monolingual Biases in Simulations of Cultural Transmission

Recent research suggests that the evolution of language is affected by the inductive biases of its learners. I suggest that there is an implicit assumption that one of these biases is to expect a single linguistic system in the input. Given the prevalence of bilingual cultures, this may not be a valid abstraction. This is illustrated by demonstrating that the ‘minimal naming game’ model, in which a shared lexicon evolves in a population of agents, includes an implicit mutual exclusivity bias. Since recent research suggests that children raised in bilingual cultures do not exhibit mutual exclusivity, the individual learning algorithm of the agents is not as abstract as it appears to be. A modification of this model demonstrates that communicative success can be achieved without mutual exclusivity. It is concluded that complex cultural phenomena, such as bilingualism, do not necessarily result from complex individual learning mechanisms. Rather, the cultural process itself can bring about this complexity