2,217 research outputs found
Recursive weighted PLS (rPLS):an efficient and promising multivariate method for spectral variable selection in regression
A Game-Based Learning Approach To Enhance Understanding Of Interface Design Principles In Design Education
The design of user interface is an important and challenging topic for student designers to understand and master. The eight principles of good User Interface (UI) design are often taught using primarily cognitive approaches, which can leave room for improvement in studentsâ ability to apply the principles in a variety of contexts. Game-based learning tools are recognised to be beneficial in university classrooms across a variety of discipline areas and topics due to their capacity to increase engagement. This project presents a first prototype for an instructional tool that leverages constructionism and embodied learning to enhance studentsâ understanding and application of these principles. This tool takes the form of a board game, thus encouraging peer learning. To test the prototype, three usability tests were carried out. Each user group was unique, the first being internal to the design team, the second having some prior exposure of the subject, and the third, having no prior experience at all. In each sessions, the participants were presented with a series of UI challenges, for which they were asked to construct suitable design solutions. Following the sessions, and where possible, the quality of these solutions were evaluated against a scoring system. This initial study suggests that instructional board games may be flexible enough to support learning outcomes at various stages of knowledge and skills acquisition among different learner groups
Nanoplasmonic NO2Sensor with a Sub-10 Parts per Billion Limit of Detection in Urban Air
Urban air pollution is a critical health problem in cities all around the world. Therefore, spatially highly resolved real-time monitoring of airborne pollutants, in general, and of nitrogen dioxide, NO2, in particular, is of utmost importance. However, highly accurate but fixed and bulky measurement stations or satellites are used for this purpose to date. This defines a need for miniaturized NO2 sensor solutions with detection limits in the low parts per billion range to finally enable indicative air quality monitoring at low cost that facilitates detection of highly local emission peaks and enables the implementation of direct local actions like traffic control, to immediately reduce local emissions. To address this challenge, we present a nanoplasmonic NO2 sensor based on arrays of Au nanoparticles coated with a thin layer of polycrystalline WO3, which displays a spectral redshift in the localized surface plasmon resonance in response to NO2. Sensor performance is characterized under (i) idealized laboratory conditions, (ii) conditions simulating humid urban air, and (iii) an outdoor field test in a miniaturized device benchmarked against a commercial NO2 sensor approved according to European and American standards. The limit of detection of the plasmonic solution is below 10 ppb in all conditions. The observed plasmonic response is attributed to a combination of charge transfer between the WO3 layer and the plasmonic Au nanoparticles, WO3 layer volume expansion, and changes in WO3 permittivity. The obtained results highlight the viability of nanoplasmonic gas sensors, in general, and their potential for practical application in indicative urban air monitoring, in particular
A note on quasinormal modes: A tale of two treatments
There is an apparent discrepancy in the literature with regard to the
quasinormal mode frequencies of Schwarzschild-de Sitter black holes in the
degenerate-horizon limit. On the one hand, a Poschl-Teller-inspired method
predicts that the real part of the frequencies will depend strongly on the
orbital angular momentum of the perturbation field whereas, on the other hand,
the degenerate limit of a monodromy-based calculation suggests there should be
no such dependence (at least, for the highly damped modes). In the current
paper, we provide a possible resolution by critically re-assessing the limiting
procedure used in the monodromy analysis.Comment: 11 pages, Revtex format; (v2) new addendum in response to reader
comments, also references, footnote and acknowledgments adde
Soft Photons in Hadron-Hadron Collisions: Synchrotron Radiation from the QCD Vacuum?
We discuss the production of soft photons in high energy hadron-hadron
collisions. We present a model where quarks and antiquarks in the hadrons emit
``synchrotron light'' when being deflected by the chromomagnetic fields of the
QCD vacuum, which we assume to have a nonperturbative structure. This gives a
source of prompt soft photons with frequencies in the c.m.
system of the collision in addition to hadronic bremsstrahlung. In comparing
the frequency spectrum and rate of ``synchrotron'' photons to experimental
results we find some supporting evidence for their existence. We make an
exclusive--inclusive connection argument to deduce from the ``synchrotron''
effect a behaviour of the neutron electric formfactor proportional
to for . We find this to be consistent with
available data. In our view, soft photon production in high energy
hadron-hadron and lepton-hadron collisions as well as the behaviour of
electromagnetic hadron formfactors for low are thus sensitive probes of
the nonperturbative structure of the QCD vacuum.Comment: Heidelberg preprint HD-THEP-94-36, 31 pages, LaTeX + ZJCITE.sty
(included), 12 figures appended as uuencoded compressed ps-fil
Self-similar spherically symmetric cosmological models with a perfect fluid and a scalar field
Self-similar, spherically symmetric cosmological models with a perfect fluid
and a scalar field with an exponential potential are investigated. New
variables are defined which lead to a compact state space, and dynamical
systems methods are utilised to analyse the models. Due to the existence of
monotone functions global dynamical results can be deduced. In particular, all
of the future and past attractors for these models are obtained and the global
results are discussed. The essential physical results are that initially
expanding models always evolve away from a massless scalar field model with an
initial singularity and, depending on the parameters of the models, either
recollapse to a second singularity or expand forever towards a flat power-law
inflationary model. The special cases in which there is no barotropic fluid and
in which the scalar field is massless are considered in more detail in order to
illustrate the asymptotic results. Some phase portraits are presented and the
intermediate dynamics and hence the physical properties of the models are
discussed.Comment: 31 pages, 4 figure
Visions of Utopia: Sweden, the BBC and the Welfare State
Drawing on manuscripts and transcripts of BBC programme output, and material from the Radio Times, and the BBCâs The Listener magazine, this article analyses radio talks and programmes that focused on Sweden in the immediate years after the Second World War when the Swedish model was widely popularised abroad. The article argues that BBC output entangled domestic politics and transnational ideas around post-war reconstruction and welfare. Sweden was used as a lens through which a modern welfare state could be visualised and justified. This was however Utopia in two senses since the image of Sweden presented was in itself a highly idealised representation
UV-Deprived Coloration Reduces Success in Mate Acquisition in Male Sand Lizards (Lacerta agilis)
Background: Recent work on animal signals has revealed a wide occurrence of UV signals in tetrapods, in particular birds, but also in lizards (and perhaps other Squamate reptiles). Our previous work on the Swedish sand lizard (Lacerta agilis) has verified, both in correlative selection analyses in the wild and with laboratory and field experiments, the importance of the green âbadge â on the body sides of adult males for securing mating opportunities, probably mostly through deterring rival males rather than attracting females. The role of UV in communication has, however, never been examined. Methodology/Principal Findings: Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV. By UV-depriving the signal (reflectance) with sun block chemicals fixated with permeable, harmless spray dressing, we show that males in the control group (spray dressing only) had significantly higher success in mate acquisition than UV-deprived males. Conclusions/Significance: These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards
The effect of travel restrictions on the spread of a moderately contagious disease
BACKGROUND: Much research in epidemiology has been focused on evaluating conventional methods of control strategies in the event of an epidemic or pandemic. Travel restrictions are often suggested as an efficient way to reduce the spread of a contagious disease that threatens public health, but few papers have studied in depth the effects of travel restrictions. In this study, we investigated what effect different levels of travel restrictions might have on the speed and geographical spread of an outbreak of a disease similar to severe acute respiratory syndrome (SARS). METHODS: We used a stochastic simulation model incorporating survey data of travel patterns between municipalities in Sweden collected over 3 years. We tested scenarios of travel restrictions in which travel over distances >50 km and 20 km would be banned, taking into account different levels of compliance. RESULTS: We found that a ban on journeys >50 km would drastically reduce the speed and geographical spread of outbreaks, even when compliance is < 100%. The result was found to be robust for different rates of intermunicipality transmission intensities. CONCLUSION: This study supports travel restrictions as an effective way to mitigate the effect of a future disease outbreak
One and two dimensional analysis of 3pi correlations measured in Pb+Pb interactions
3pi- correlations from Pb+Pb collisions at 158 GeV/c per nucleon are
presented as measured by the focusing spectrometer of the NA44 experiment at
CERN. The three-body effect is found to be stronger for PbPb than for SPb. The
two-dimensional three-particle correlation function is also measured and the
longitudinal extension of the source is larger than the transverse extension
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