155 research outputs found
The Effects Of Caffeine On Athletic Performance
Athletes who use caffeine before exercising or competition may be upgrading themselves more than they realize. Caffeine is classified as a stimulant and is the most commonly used drug in the world. Caffeine has the same affects that amphetamines and cocaine have, just to a lesser degree. Caffeine crosses the membranes of all the bodyâs tissues. It can exert effects on the central nervous system and the peripheral tissues that result in physiological effects. Studies have shown that caffeine improves performance in a variety of different activities. This stimulant has been shown to be a powerful ergogenic aid that is beneficial in athletic training and performance. Caffeine has been found to increase speed and power, improve the length of training, and assist the athlete in resisting fatigue. Caffeine has been found to stimulate the brain, which contributes to clearer thinking and ability to concentrate more intensely on the task at hand. Studies have shown that up to 25% of athleteâs ages 11-18 years old have used caffeine in an effort to increase their athletic performances. Because of caffeineâs effect on the body and its ability to increase an athleteâs performance, Olympic Committees have debated on whether caffeine should be tested before the Olympic Games
Atoms in the Surf: Molecular Dynamics Simulation of the Kelvin-Helmholtz Instability using 9 Billion Atoms
We present a fluid dynamics video showing the results of a 9-billion atom
molecular dynamics simulation of complex fluid flow in molten copper and
aluminum. Starting with an atomically flat interface, a shear is imposed along
the copper-aluminum interface and random atomic fluctuations seed the formation
of vortices. These vortices grow due to the Kelvin-Helmholtz instability. The
resulting vortical structures are beautifully intricate, decorated with
secondary instabilities and complex mixing phenomena. This work performed under
the auspices of the U.S. Department of Energy by Lawrence Livermore National
Laboratory under Contract DE-AC52-07NA27344.Comment: Description of video submitted to APS DFD Gallery of Fluid Motion
200
Non-magnetic impurities in two dimensional superconductors
A numerical approach to disordered 2D superconductors described by BCS mean
field theory is outlined. The energy gap and the superfluid density at zero
temperature and the quasiparticle density of states are studied. The method
involves approximate self-consistent solutions of the Bogolubov-deGennes
equations on finite square lattices. Where comparison is possible, the results
of standard analytic approaches to this problem are reproduced. Detailed
modeling of impurity effects is practical using this approach. The {\it range}
of the impurity potential is shown to be of {\it quantitative importance} in
the case of strong potential scatterers. We discuss the implications for
experiments, such as the rapid suppression of superconductivity by Zn doping in
Copper-Oxide superconductors.Comment: 16 pages, latex, 8 figures( available upon request
Patenting and licensing of university research: promoting innovation or undermining academic values?
Since the 1980s in the US and the 1990s in Europe, patenting and licensing activities by universities have massively increased. This is strongly encouraged by governments throughout the Western world. Many regard academic patenting as essential to achieve 'knowledge transfer' from academia to industry. This trend has far-reaching consequences for access to the fruits of academic research and so the question arises whether the current policies are indeed promoting innovation or whether they are instead a symptom of a pro-intellectual property (IP) culture which is blind to adverse effects. Addressing this question requires both empirical analysis (how real is the link between academic patenting and licensing and 'development' of academic research by industry?) and normative assessment (which justifications are given for the current policies and to what extent do they threaten important academic values?). After illustrating the major rise of academic patenting and licensing in the US and Europe and commenting on the increasing trend of 'upstream' patenting and the focus on exclusive as opposed to non-exclusive licences, this paper will discuss five negative effects of these trends. Subsequently, the question as to why policymakers seem to ignore these adverse effects will be addressed. Finally, a number of proposals for improving university policies will be made
The interpretation of polycrystalline coherent inelastic neutron scattering from aluminium
A new approach to the interpretation and analysis of coherent inelastic neutron scattering
from polycrystals (poly-CINS) is presented. Here we describe a simulation of the one-phonon coherent inelastic scattering from a lattice model of an arbitrary crystal system. The one-phonon component is characterized by sharp features e.g. determined by boundaries of the (Q, omega) regions where one-phonon scattering is allowed. These features may be identified with the same features apparent in the measured total coherent inelastic cross-section, the other components of which(multiphonon or multiple scattering) show no sharp features. The parameters of the model can then be relaxed to improve the fit between model and experiment. This method is of particular interest where
no single crystals are available. To test the approach, we have measured the poly-CINS for polycrystalline aluminium using the MARI spectrometer (ISIS) because both lattice dynamical models and measured dispersion curves are available for this material. The models used include a
simple Lennard-Jones model fitted to the elastic constants of this material plus a number of Embedded Atom Method (EAM) force fields. The agreement obtained suggests that the method demonstrated should be effective in developing models for other materials where single crystal dispersion curves are not available
Automating unobtrusive personalized services in ambient media environments
The final publication is available at Springer via http://dx.doi.org/10.1007/s11042-013-1634-2In the age of ambient media, people are surrounded by lots of physical objects (media objects) for rendering the digital world in the natural environment. These media objects should interact with users in a way that is not disturbing for them. To address this issue, this work presents a design and automation strategy for augmenting the world around us with personalized ambient media services that behave in a considerate manner. That is, ambient services are capable of adjusting its obtrusiveness level (i.e., the extent to which each service intrudes the userÂżs mind) by using the appropriate media objects for each userÂżs situation.This work has been developed with the support of MICINN, under the project EVERYWARE TIN2010-18011, and the support of the Christian Doppler Forschungsgesellschaft and the BMWFJ, Austria.Serral Asensio, E.; Gil Pascual, M.; Valderas Aranda, PJ.; Pelechano Ferragud, V. (2014). Automating unobtrusive personalized services in ambient media environments. Multimedia Tools and Applications. 71(1):159-178. https://doi.org/10.1007/s11042-013-1634-2S159178711Bencomo N, Grace P, Flores-CortĂ©s CA, Hughes D, Blair GS (2008) Genie: supporting the model driven development of reflective, component-based adaptive systems. In: ICSE, pp 811â814Blumendorf M, Lehmann G, Albayrak S (2010) Bridging models and systems at runtime to build adaptive user interfaces. In: Proc. of EICS 2010. ACM, pp 9â18Brown DM (2010) Communicating design: developing web site documentation for design and planning, 2nd edn. New Riders PressCalinescu R (2011) When the requirements for adaptation and high integrity meet. In: Proceedings of the 8th workshop on assurances for self-adaptive systems, ASAS â11. ACM, New York, pp 1â4Filieri A, Ghezzi C, Tamburrelli G (2011) Run-time efficient probabilistic model checking. In: Proceedings of the 33rd International Conference on Software Engineering, ICSE â11. ACM, New York, pp 341â350Gershenfeld N, Krikorian R, Cohen D (2004) The internet of things. Sci Am 291(4):46â51Gibbs WW (2005) Considerate computing. Sci Am 292(1):54â61Gulliksen J, Goransson B, Boivie I, Blomkvist S, Persson J, Cajander A (2003) Key principles for user-centred systems design. Behav Inform Technol 22:397â409Hinckley K, Horvitz E (2001) Toward more sensitive mobile phones. In: Proc. of the UIST â01, pp 191â192Ho J, Intille SS (2005) Using context-aware computing to reduce the perceived burden of interruptions from mobile devices. In: Proc. of CHI â05. ACM, pp 909â918Horvitz E, Kadie C, Paek T, Hovel D (2003) Models of attention in computing and communication: from principles to applications. Commun ACM 46:52â59Ju W, Leifer L (2008) The design of implicit interactions: making interactive systems less obnoxious. Des Issues 24(3):72â84Kortuem G, Kawsar F, Fitton D, Sundramoorthy V (2010) Smart objects as building blocks for the internet of things. IEEE Internet Comput 14(1):44â51Lewis JR (1995) Ibm computer usability satisfaction questionnaires: psychometric evaluation and instructions for use. Int J Hum Comput Interact 7(1):57â78Lugmayr A, Risse T, Stockleben B, Laurila K, Kaario J (2009) Semantic ambient mediaâan introduction. Multimed Tools Appl 43(3):337â359Mattern F (2003) From smart devices to smart everyday objects. In: Proc. Smart Objects Conf. (SOC 03). Springer, pp 15â16Morin B, Barais O, Jezequel JM, Fleurey F, Solberg A (2009) Models run.time to support dynamic adaptation. Comput 42(10):44â51Nelson L, Churchill EF (2005) User experience of physical-digital object systems: implications for representation and infrastructure. Paper presented at smart object systems workshop, in cojunction with ubicomp 2005PaternĂČ F (2002) Concurtasktrees: an engineered approach to model-based design of interactive systems. In: L.E. Associates (ed) The handbook of analysis for human-computer interaction, pp 483â500PaternĂČ F (2003) From model-based to natural development. HCI International, pp 592â596Ramchurn SD, Deitch B, Thompson MK, Roure DCD, Jennings NR, Luck M (2004) Minimising intrusiveness in pervasive computing environments using multi-agent negotiation. MobiQuitous â04, pp 364â372Runeson P, Höst M (2009) Guidelines for conducting and reporting case study research in software engineering. Empir Softw Eng 14(2):131â164Schmidt A (2000) Implicit human computer interaction through context. Pers Technol 4(2â3):191â199Serral E, Valderas P, Pelechano V (2010) Supporting runtime system evolution to adapt to user behaviour. In: Proc. of CAiSEâ10, pp 378â392Serral E, Valderas P, Pelechano V (2010) Towards the model driven development of context-aware pervasive systems. PMC 6(2):254â280Siegemund F (2004) A context-aware communication platform for smart objects. In: Proc of the int conf on pervasive computing. Springer, pp 69â86Streitz NA, Rocker C, Prante T, Alphen Dv, Stenzel R, Magerkurth C (2005) Designing smart artifacts for smart environments. Comput 38(3):41â49. doi: 10.1109/MC.2005.92Thiesse F, Kohler M (2008) An analysis of usage-based pricing policies for smart products. Electron Mark 18(3):232â241. doi: 10.1080/10196780802265751Vastenburg MH, Keyson DV, de Ridder H (2008) Considerate home notification systems: a field study of acceptability of notifications in the home. Pers Ubiquit Comput 12(8):555â56
The dissociation catastrophe in fluctuating-charge models and its implications for the concept of atomic electronegativity
We have recently developed the QTPIE (charge transfer with polarization
current equilibration) fluctuating-charge model, a new model with correct
dissociation behavior for nonequilibrium geometries. The correct asymptotics
originally came at the price of representing the solution in terms of
charge-transfer variables instead of atomic charges. However, we have found an
exact reformulation of fluctuating-charge models in terms of atomic charges
again, which is made possible by the symmetries of classical electrostatics. We
show how this leads to the distinguishing between two types of atomic
electronegativities in our model. While one is a intrinsic property of
individual atoms, the other takes into account the local electrical
surroundings. This suggests that this distinction could resolve some confusion
surrounding the concept of electronegativity as to whether it is an intrinsic
property of elements, or otherwise.Comment: 17 pages, prepared for "Proceedings of QSCP-XIII" in Prog. Theor.
Chem. Phy
Seven HCI Grand Challenges
This article aims to investigate the Grand Challenges which arise in the current and emerging landscape of rapid technological evolution towards more intelligent interactive technologies, coupled with increased and widened societal needs, as well as individual and collective expectations that HCI, as a discipline, is called upon to address. A perspective oriented to humane and social values is adopted, formulating the challenges in terms of the impact of emerging intelligent interactive technologies on human life both at the individual and societal levels. Seven Grand Challenges are identified and presented in this article: Human-Technology Symbiosis; Human-Environment Interactions; Ethics, Privacy and Security; Well-being, Health and Eudaimonia; Accessibility and Universal Access; Learning and Creativity; and Social Organization and Democracy. Although not exhaustive, they summarize the views and research priorities of an international interdisciplinary group of experts, reflecting different scientific perspectives, methodological approaches and application domains. Each identified Grand Challenge is analyzed in terms of: concept and problem definition; main research issues involved and state of the art; and associated emerging requirements
Morphological effects on IR band profiles: Experimental spectroscopic analysis with application to observed spectra of oxygen-rich AGB stars
To trace the source of the unique 13, 19.5, and 28 m emission features
in the spectra of oxygen-rich circumstellar shells around AGB stars, we have
compared dust extinction spectra obtained by aerosol measurements. We have
measured the extinction spectra for 19 oxide powder samples of eight different
types, such as Ti-compounds (TiO, TiO, TiO, TiO,
AlTiO, CaTiO), -, -,
---AlO, and MgAlO in the infrared region
(10 - 50 m) paying special attention to the morphological (size, shape,
and agglomeration) effects and the differences in crystal structure. Anatase
(TiO) particles with rounded edges are the possible 13, 19.5 and 28 m
band carriers as the main contributor in the spectra of AGB stars, and
spherically shaped nano-sized spinel and AlTiO dust grains are possibly
associated with the anatase, enhancing the prominence of the 13 m feature
and providing additional features at 28 m. The extinction data sets
obtained by the aerosol and CsI pellet measurements have been made available
for public use at http://elbe.astro.uni-jena.deComment: 17 pages, 8 figures, Accepted 24 March 2009 for publication in A&
Equal opportunities: Do shareable interfaces promote more group participation than single users displays?
Computers designed for single use are often appropriated suboptimally when used by small colocated groups working together. Our research investigates whether shareable interfacesâthat are designed for more than one user to inter-act withâcan facilitate more equitable participation in colocated group settings compared with single user displays. We present a conceptual framework that
characterizes Shared Information Spaces (SISs) in terms of how they constrain and invite participation using different entry points. An experiment was conducted that compared three different SISs: a physical-digital set-up (least constrained), a multitouch tabletop (medium), and a laptop display (most constrained). Statistical analyses showed there to be little difference in participation levels between the three conditions other than a predictable lack of equity of control over the interface in the laptop condition. However, detailed qualitative analyses revealed more equitable participation took place in the physical-digital condition in terms of verbal utterances over time. Those who spoke the least contributed most to the physical design task. The findings are discussed in relation to the conceptual framework and, more generally, in terms of how to select, design, and combine different display technologies to support collaborative activities
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