4,697 research outputs found
Dynamics of tilt-based browsing on mobile devices
A tilt-controlled photo browsing method for small mobile devices is presented. The implementation uses continuous inputs from an accelerometer, and a multimodal (visual, audio and vibrotactile) display coupled with the states of this model. The model is based on a simple physical model, with its characteristics shaped to enhance usability. We show how the dynamics of the physical model can be shaped to make the handling qualities of the mobile device fit the browsing task. We implemented the proposed algorithm on Samsung MITs PDA with tri-axis accelerometer and a vibrotactile motor. The experiment used seven novice users browsing from 100 photos. We compare a tilt-based interaction method with a button-based browser and an iPod wheel. We discuss the usability performance and contrast this with subjective experience from the users. The iPod wheel has significantly poorer performance than button pushing or tilt interaction, despite its commercial popularity
The Liquid-Gas Phase Transitions in a Multicomponent Nuclear System with Coulomb and Surface Effects
The liquid-gas phase transition is studied in a multi-component nuclear
system using a local Skyrme interaction with Coulomb and surface effects. Some
features are qualitatively the same as the results of Muller and Serot which
uses relativistic mean field without Coulomb and surface effects. Surface
tension brings the coexistance binodal surface to lower pressure. The Coulomb
interaction makes the binodal surface smaller and cause another pair of binodal
points at low pressure and large proton fraction with less protons in liquid
phase and more protons in gas phase.Comment: 20 pages including 7 postscript figure
SELF-DUAL ANYONS IN UNIFORM BACKGROUND FIELDS
We study relativistic self-dual Chern-Simons-Higgs systems in the presence of
uniform background fields that explicitly break CTP. A rich, but discrete
vacuum structure is found when the gauge symmetry is spontaneously broken,
while the symmetric phase can have an infinite vacuum degeneracy at tree level.
The latter is due to the proliferation of neutral solitonic states that cost
zero energy. Various novel self-dual solitons, such as these, are found in both
the symmetric and the asymmetric phases. Also by considering a similar system
on a two-sphere and the subsequent large sphere limit, we isolate sensible and
finite expressions for the conserved angular and linear momenta, which satisfy
anomalous commutation relations. We conclude with a few remarks on unresolved
issues.Comment: LaTeX, 20 pages, 4 uuencoded figures included
The BPS Domain Wall Solutions in Self-Dual Chern-Simons-Higgs Systems
We study domain wall solitons in the relativistic self-dual Chern-Simons
Higgs systems by the dimensional reduction method to two dimensional spacetime.
The Bogomolny bound on the energy is given by two conserved quantities in a
similar way that the energy bound for BPS dyons is set in some Yang-Mills-Higgs
systems in four dimensions. We find the explicit soliton configurations which
saturate the energy bound and their nonrelativistic counter parts. We also
discuss the underlying N=2 supersymmetry.Comment: 16 pages, LaTeX, no figure, a minor change in acknowledgment
Quantum Monte Carlo Calculations of Pion Scattering from Li
We show that the neutron and proton transition densities predicted by recent
quantum Monte Carlo calculations for A=6,7 nuclei are consistent with pion
scattering from 6Li and 7Li at energies near the Delta resonance. This has
provided a microscopic understanding of the enhancement factors for quadrople
excitations, which were needed to describe pion inelastic scattering within the
nuclear shell model of Cohen and Kurath.Comment: 10 pages, REVTeX, 3 postscript figures; added calculation of elastic
and inelastic pion scattering from 6Li at multiple energie
Smartphone apps for the self-management of low back pain: A systematic review
Guidelines for low back pain (LBP) often recommend the use of self-management such as unsupervised exercise, booklets, and online education. Another potentially useful way for patients to self-manage LBP is by using smartphone applications (apps). However, to date, there has been no rigorous evaluation of LBP apps and no guidance for consumers on how to select high-quality, evidence-based apps. This chapter reviews smartphone apps for the self-management of LBP and evaluates their content quality and whether they recommend evidence-based interventions. This chapter shows that generally app developers are selecting interventions that are endorsed by guidelines, although their quality is low. There are many apps available for the self-management of LBP, but their effectiveness in improving patient outcomes has not been rigorously assessed. App developers need to work closely with healthcare professionals, researchers, and patients to ensure app content is accurate, evidence based, and engaging
Contact-induced spin polarization in carbon nanotubes
Motivated by the possibility of combining spintronics with molecular
structures, we investigate the conditions for the appearance of
spin-polarization in low-dimensional tubular systems by contacting them to a
magnetic substrate. We derive a set of general expressions describing the
charge transfer between the tube and the substrate and the relative energy
costs. The mean-field solution of the general expressions provides an
insightful formula for the induced spin-polarization. Using a tight-binding
model for the electronic structure we are able to estimate the magnitude and
the stability of the induced moment. This indicates that a significant magnetic
moment in carbon nanotubes can be observed.Comment: To appear in Phys. Rev. B (2003
Using enzyme activities as an indicator of soil fertility in grassland - an academic dilemma.
Grasslands play an important role in conserving natural biodiversity and providing ecosystem functions and services for societies. Soil fertility is an important property in grassland, and the monitoring of soil fertility can provide crucial information to optimize ecosystem productivity and sustainability. Testing various soil physiochemical properties related to fertility usually relies on traditional measures, such as destructive sampling, pre-test treatments, labor-intensive procedures, and costly laboratory measurements, which are often difficult to perform. However, soil enzyme activity reflecting the intensity of soil biochemical reactions is a reliable indicator of soil properties and thus enzyme assays could be an efficient alternative to evaluate soil fertility. Here, we review the latest research on the features and functions of enzymes catalyzing the biochemical processes that convert organic materials to available plant nutrients, increase soil carbon and nutrient cycling, and enhance microbial activities to improve soil fertility. We focus on the complex relationships among soil enzyme activities and functions, microbial biomass, physiochemical properties, and soil/crop management practices. We highlight the biochemistry of enzymes and the rationale for using enzyme activities to indicate soil fertility. Finally, we discuss the limits and disadvantages of the potential new molecular tool and provide suggestions to improve the reliability and feasibility of the proposed alternative
Parametrization of nonlinear and chaotic oscillations in driven beam-plasma diodes
Nonlinear phenomena in a driven plasma diode are studied using a fluid code and the particle-in-cell simulation code XPDPI. When a uniform electron beam is injected to a bounded diode filled with uniform ion background, the beam is destabilized by the Pierce instability and a perturbation grows to exhibit nonlinear oscillations including chaos. Two standard routes to chaos, period doubling and quasiperiodicity, are observed. Mode lockings of various winding numbers are observed in an ac driven system. A new diagnostic quantity is used to parametrize various nonlinear oscillations.open10
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