1,074 research outputs found
Electronic marking and identification techniques to discourage document copying
Modern computer networks make it possible to distribute documents quickly and economically by electronic means rather than by conventional paper means. However, the widespread adoption of electronic distribution of copyrighted material is currently impeded by the ease of illicit copying and dissemination. In this paper we propose techniques that discourage illicit distribution by embedding each document with a unique codeword. Our encoding techniques are indiscernible by readers, yet enable us to identify the sanctioned recipient of a document by examination of a recovered document. We propose three coding methods, describe one in detail, and present experimental results showing that our identification techniques are highly reliable, even after documents have been photocopied
Commercial hospitality : a vehicle for the sustainable empowerment of Nepali women
To illustrate how commercial hospitality has catalysed sustainable social change in Nepal through empowering women. Utilising a new framework, developed by combining existing theories, empowerment of women Tea House owners/ managers is assessed. Within a critical feminist paradigm, primary research consisting of interviews and participant observation was undertaken in Nepal over a three month period in the central region of Nepal. Involvement in the hospitality industry improved the livelihoods of the women Tea House owners/ managers, it also has the potential to facilitate sustainable empowerment for future generations, providing them with education, choice, control and opportunities. Although steps were taken to limit rhetorical issues, language barriers could have influenced the findings of the interviews. To fully investigate the potential for hospitality to act as a vehicle for the sustainable empowerment of women, it is suggested that this study be replicated again in another region or that a detailed ethnographic study be carried out. Demonstrates how the commercial hospitality industry can be a force for good; women working in the industry are agents of change, actively improving their levels of empowerment in their immediate environment. The commercial hospitality industry has pioneered the empowerment of women and this could lay the foundation for the further emancipation of women. To date, there has been limited research into the relationship between involvement in the commercial hospitality sector and the empowerment of women; this paper begins to fill this gap by investigating a tourist region of Nepal
A Climatology of Tropospheric Zonal-Mean Water Vapor Fields and Fluxes in Isentropic Coordinates
Based on reanalysis data for the years 1980–2001 from the European Centre for Medium-Range Weather Forecasts (ERA-40 data), a climatology of tropospheric zonal-mean water vapor fields and fluxes in isentropic coordinates is presented. In the extratropical free troposphere, eddy fluxes dominate the meridional flux of specific humidity along isentropes. At all levels, isentropic eddy fluxes transport water vapor from the deep Tropics through the subtropics into the extratropics. Isentropic eddy fluxes of specific humidity diverge near the surface and in the tropical and subtropical free troposphere; they converge in the extratropical free troposphere. Isentropic mean advective fluxes of specific humidity play a secondary role in the meridional water vapor transport in the free troposphere; however, they dominate the meridional flux of specific humidity near the surface, where they transport water vapor equatorward and, in the solstice seasons, across the equator. Cross-isentropic mean advective fluxes of specific humidity are especially important in the Hadley circulation, in whose ascending branches they moisten and in whose descending branches they dry the free troposphere.
Near the minima of zonal-mean relative humidity in the subtropical free troposphere, the divergence of the cross-isentropic mean advective flux of specific humidity in the descending branches of the Hadley circulation is the dominant divergence in the mean specific humidity balance; it is primarily balanced by convergence of cross-isentropic turbulent fluxes that transport water vapor from the surface upward. Although there are significant isentropic eddy fluxes of specific humidity through the region of the subtropical relative humidity minima, their divergence near the minima is generally small compared with the divergence of cross-isentropic mean advective fluxes, implying that moistening by eddy transport from the Tropics into the region of the minima approximately balances drying by eddy transport into the extratropics. That drying by cross-isentropic mean subsidence near the subtropical relative humidity minima is primarily balanced by moistening by upward turbulent fluxes of specific humidity, likely in convective clouds, suggests cloud dynamics may play a central role in controlling the relative humidity of the subtropical free troposphere
ALMA observations of TiO around VY Canis Majoris
Titanium dioxide, TiO, is a refractory species that could play a crucial
role in the dust-condensation sequence around oxygen-rich evolved stars. To
date, gas phase TiO has been detected only in the complex environment of
the red supergiant VY CMa. We aim to constrain the distribution and excitation
of TiO around VY CMa in order to clarify its role in dust formation. We
analyse spectra and channel maps for TiO extracted from ALMA science
verification data. We detect 15 transitions of TiO, and spatially resolve
the emission for the first time. The maps demonstrate a highly clumpy,
anisotropic outflow in which the TiO emission likely traces gas exposed to
the stellar radiation field. A roughly east-west oriented, accelerating
bipolar-like structure is found, of which the blue component runs into and
breaks up around a solid continuum component. A distinct tail to the south-west
is seen for some transitions, consistent with features seen in the optical and
near-infrared. We find that a significant fraction of TiO remains in the
gas phase outside the dust-formation zone and suggest that this species might
play only a minor role in the dust-condensation process around extreme
oxygen-rich evolved stars like VY CMa.Comment: Accepted for publication in Astronomy & Astrophysics, 25 pages, 20
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A Replica Inference Approach to Unsupervised Multi-Scale Image Segmentation
We apply a replica inference based Potts model method to unsupervised image
segmentation on multiple scales. This approach was inspired by the statistical
mechanics problem of "community detection" and its phase diagram. Specifically,
the problem is cast as identifying tightly bound clusters ("communities" or
"solutes") against a background or "solvent". Within our multiresolution
approach, we compute information theory based correlations among multiple
solutions ("replicas") of the same graph over a range of resolutions.
Significant multiresolution structures are identified by replica correlations
as manifest in information theory overlaps. With the aid of these correlations
as well as thermodynamic measures, the phase diagram of the corresponding Potts
model is analyzed both at zero and finite temperatures. Optimal parameters
corresponding to a sensible unsupervised segmentation correspond to the "easy
phase" of the Potts model. Our algorithm is fast and shown to be at least as
accurate as the best algorithms to date and to be especially suited to the
detection of camouflaged images.Comment: 26 pages, 22 figure
‘Block teaching’ – exploring lecturers' perceptions of intensive modes of delivery in the context of undergraduate education
This article evaluates changes in teaching delivery during the first year of an undergraduate Tourism Management degree programme at a university in the North West of England. Moving from traditional semesterised mode, delivery was changed to shortened, time-intensive modules delivered one at a time, for two full days (six hours per day) over a three-week period. This was implemented in response to student feedback and concerns regarding student outcomes. Albeit limited, previous research suggests that intensive forms of delivery can improve engagement, attendance and attainment, particularly amongst students from diverse entry pathways. Although it is clear that the efficacy of block teaching relies heavily on – and creates new pressures for – teaching staff, little research has explored those impacts. Here instead, the perceptions of teaching staff were the focus. A qualitative approach was taken using an anonymous, online questionnaire, completed following one full year of block teaching. Findings suggest that, although most lecturers found that block teaching enabled them to manage their time more effectively, as the year progressed, block teaching negatively affected student attendance and subsequently hampered deep learning. Fully-integrated placement of assessment and use of one intensive module to aid transition was recommended to help overcome these issues
Long‐term exposure to higher temperature increases the thermal sensitivity of grazer metabolism and movement
Ecological studies of global warming impacts have many constraints. Organisms are often exposed to higher temperatures for short periods of time, probably underestimating their ability to acclimate or adapt relative to slower but real rates of warming. Many studies also focus on a limited number of traits and miss the multifaceted effects that warming may have on organisms, from physiology to behaviour. Organisms exhibit different movement traits, some of which are primarily driven by metabolic processes and others by decision-making, which should influence the extent to which temperature affects them. We collected snails from streams that have been differentially heated by geothermal activity for decades to determine how long-term exposure to different temperatures affected their metabolism and movement. Additionally, we collected snails from a cold stream (5°C) and measured their metabolism and movement at higher temperatures (short-term exposure). We used respirometry to measure metabolic rates and automated in situ image-based tracking to quantify several movement traits from 5 to 21°C. Long-term exposure to higher temperatures resulted in a greater thermal sensitivity of metabolic rate compared to snails exposed for short durations, highlighting the need for caution when conducting acute temperature exposures in global warming research. Average speed, which is largely driven by metabolism, also increased more with temperature for long-term exposure compared to short-term exposure. Movement traits we interpret as more decision-based, such as time spent moving and trajectory shape, were less affected by temperature. Step length increased and step angle decreased at higher temperatures for both long- and short-term exposure, resulting in overall straighter trajectories. The power-law exponent of the step length distributions and fractal dimension of trajectories were independent of temperature, however, suggesting that snails retained the same movement strategy. The observed changes in snail movement at higher temperatures should lead to higher encounter rates and more efficient searching, providing a behavioural mechanism for stronger plant–herbivore interactions in warmer environments. Our research is among the first to show that temperature has contrasting effects on different movement traits, which may be determined by the metabolic contribution to those behaviours
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