Inclination Measurement of Human Movement Using a 3-D Accelerometer With Autocalibration

In the medical field, accelerometers are often used for measuring inclination of body segments and activity of daily living (ADL) because they are small and require little power. A drawback of using accelerometers is the poor quality of inclination estimate for movements with large accelerations. This paper describes the design and performance of a Kalman filter to estimate inclination from the signals of a triaxial accelerometer. This design is based on assumptions concerning the frequency content of the acceleration of the movement that is measured, the knowledge that the magnitude of the gravity is 1 g and taking into account a fluctuating sensor offset. It is shown that for measuring trunk and pelvis inclination during the functional three-dimensional activity of stacking crates, the inclination error that is made is approximately 2/spl deg/ root-mean square. This is nearly twice as accurate as compared to current methods based on low-pass filtering of accelerometer signals

What Matters Most? A Survey of Accomplished Middle-Level Educators\u27 Beliefs and Values about Literacy

Ninety teachers working in award-winning middle schools responded to a survey that explored, quantitatively and qualitatively, how they (1) defined themselves as teachers of literacy, (2) viewed multiliteracies in adolescents\u27 lives, and (3) valued these literacies in the classroom. Mean scores indicated that Basic Literacies (e.g., comprehension, word identification, fluency, writing) were rated more favorably than New Literacies (e.g., media, Internet, critical, out of school). Strong qualitative support existed for literacy instruction in all disciplines, but interpretations varied. The most positive agreement centered on every teacher being a teacher of literacy. Little support existed for developing students\u27 out-of-school literacies in schools. Such findings have strong implications for altering curricular emphases and merging teacher practice with adolescents\u27 needs and interests

Tunable chiral spin texture in magnetic domain-walls

Magnetic domain-walls (DWs) with a preferred chirality exhibit very efficient current-driven motion. Since structural inversion asymmetry (SIA) is required for their stability, the observation of chiral domain walls in highly symmetric Pt/Co/Pt is intriguing. Here, we tune the layer asymmetry in this system and observe, by current-assisted DW depinning experiments, a small chiral field which sensitively changes. Moreover, we convincingly link the observed efficiency of DW motion to the DW texture, using DW resistance as a direct probe for the internal orientation of the DW under the influence of in-plane fields. The very delicate effect of capping layer thickness on the chiral field allows for its accurate control, which is important in designing novel materials for optimal spin-orbit-torque-driven DW motion.Comment: 12 pages, 5 figure

Tuning independently Fermi energy and spin splitting in Rashba systems: Ternary surface alloys on Ag(111)

By detailed first-principles calculations we show that the Fermi energy and the Rashba splitting in disordered ternary surface alloys (BiPbSb)/Ag(111) can be independently tuned by choosing the concentrations of Bi and Pb. The findings are explained by three fundamental mechanisms, namely the relaxation of the adatoms, the strength of the atomic spin-orbit coupling, and band filling. By mapping the Rashba characteristics,i.e.the splitting and the Rashba energy, and the Fermi energy of the surface states in the complete range of concentrations. Our results suggest to investigate experimentally effects which rely on the Rashba spin-orbit coupling in dependence on spin-orbit splitting and band filling.Comment: 11 pages, 3 figure

Goldstone modes in Lyapunov spectra of hard sphere systems

In this paper, we demonstrate how the Lyapunov exponents close to zero of a system of many hard spheres can be described as Goldstone modes, by using a Boltzmann type of approach. At low densities, the correct form is found for the wave number dependence of the exponents as well as for the corresponding eigenvectors in tangent-space. The predicted values for the Lyapunov exponents belonging to the transverse mode are within a few percent of the values found in recent simulations, the propagation velocity for the longitudinal mode is within 1%, but the value for the Lyapunov exponent belonging to the longitudinal mode deviates from the simulations by 30%. For higher densities, the predicted values deviate more from the values calculated in the simulations. These deviations may be due to contributions from ring collisions and similar terms, which, even at low densities, can contribute to the leading order.Comment: 12 pages revtex, 5 figures, accepted by Physical Review

Origin of Rashba-splitting in the quantized subbands at Bi2Se3 surface

We study the band structure of the $\text{Bi}_2\text{Se}_3$ topological insulator (111) surface using angle-resolved photoemission spectroscopy. We examine the situation where two sets of quantized subbands exhibiting different Rashba spin-splitting are created via bending of the conduction (CB) and the valence (VB) bands at the surface. While the CB subbands are strongly Rashba spin-split, the VB subbands do not exhibit clear spin-splitting. We find that CB and VB experience similar band bending magnitudes, which means, a spin-splitting discrepancy due to different surface potential gradients can be excluded. On the other hand, by comparing the experimental band structure to first principles LMTO band structure calculations, we find that the strongly spin-orbit coupled Bi 6$p$ orbitals dominate the orbital character of CB, whereas their admixture to VB is rather small. The spin-splitting discrepancy is, therefore, traced back to the difference in spin-orbit coupling between CB and VB in the respective subbands' regions

DUCAT (Dutch inventory of invasive Coronary Atherosclerosis Treatments)

Het DUCAT (Dutch inventory of invasive Coronary Atherosclerosis Treatments) project had tot doel te bepalen hoe passend behandelbeslissingen (beleidsbeslissingen) zijn bij patiënten met vernauwing van een of meer kransslagaders rond het hart (coronairlijden). DUCAT bestond uit drie delen: a) bepaling van de passendheid van behandelindicaties door een panel van deskundigen, uitgaande van drie behandelvormen: coronaire-omleidingsoperatie (CABG), 'dotteren' (PTCA), en medicamenteuze of andere niet-invasieve therapie (conservatieve behandeling); b) toetsing van de beleidsbeslissingen in tien hartcentra in Nederland aan de paneloordelen; c) het volgen van de lotgevallen van patiënten met passende en niet-passende beleidsbeslissingen. Dat laatste is beperkt gebleven tot een periode van een jaar. Hoe kan men vaststellen of een indicatie voor een ingreep passend is of niet? Ideaal zou zijn als de wetenschappelijke literatuur geen twijfel toelaat over wat de beste benadering is, maar dat is niet zo. De literatuur biedt voor vele toepassingen van CABG en vooral PTCA onvoldoende zekerheid. Er moet daarom ook een beroep worden gedaan op de ervaring van deskundigen die de indicaties in de praktijk stellen. Een aanpak - maar zeker niet de enige - om die ervaring te laten meetellen is ontwikkeld door het Amerikaanse instituut RAND in samenwerking met de Universiteit van California in Los Angeles (UCLA). De RAND/UCLA methode houdt in dat vele modelpatiënten, en bijpassende indicaties voor behandeling, worden onderscheiden op basis van combinaties van klinische kenmerken. Deskundige leden van een panel geven, op grond van de literatuur en aanvullende medische inzichten, voor elk van die modelpatiënten aan of een behandelindicatie passend, onzeker of niet-passend is. DUCAT is het eerste onderzoek in Nederland waarin deze methode is toegepast. DUCAT kende een theorie- en een praktijkdeel. In het theoriedeel kwamen twee vragen aan de orde. Hoe passend waren volgens het DUCAT-panel de vele indicaties voor behandeling bij coronairlijden en welke klinische en niet-klinische factoren hadden invloed op de oordelen van het panel? Het panel koos bij bijna de helft van de modelpatiënten voor invasieve behandeling en bij ruim een op de vijf voor conservatieve therapie, terwijl het in de rest van de gevallen geen voorkeur had voor de ene of andere benadering. Het panel vond CABG-indicaties vaker passend dan PTCA-indicaties. Het baseerde zich daarbij vooral op medische overwegingen, zoals het actuele klinische beeld en vooral de ernst van de anatomische afwijkingen. Anatomische kenmerken wogen in de oordeelsvorming zwaarder dan andere karakteristieken, zoals medicatie en de uitslag van een inspanningsproef. DUCAT richtte zich op patiënten die in het hartcentrum werden besproken op initiatief van een verwijzend cardioloog waarbij de bespreking leidde tot een beleidsbeslissing. Onze primaire belangstelling ging uit naar 3647 mensen met anatomisch gedefinieerd significant coronairlijden. De desbetreffende DUCAT-populatie bestond in doorsnee uit niet al te jonge mannen en vrouwen van wie velen zich presenteerden met een uitgebreide geschiedenis of actuele uiting van risicofactoren, ziekteverschijnselen, vatafwijkingen en behandelingen, dus met ernstige pathologie. Dat gold niet over de hele linie. Opvallend was het grote aantal mensen met eenvatslijden. Bij verreweg de meeste patiënten met significant coronairlijden opteerden de interventieartsen voor invasieve behandeling (CABG of PTCA); bij 13 procent viel de keus op conservatieve therapie. CABG kr

The Masses and Shapes of Dark Matter Halos from Galaxy-Galaxy Lensing in the CFHTLS

We present the first galaxy-galaxy weak lensing results using early data from the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). These results are based on ~22 sq. deg. of i' data. From this data, we estimate the average velocity dispersion for an L* galaxy at a redshift of 0.3 to be 137 +- 11 km/s, with a virial mass, M_{200}, of 1.1 +- 0.2 \times 10^{12} h^{-1} Msun and a rest frame R-band mass-to-light ratio of 173 +- 34 h Msun/Lsun. We also investigate various possible sources of systematic error in detail. Additionally, we separate our lens sample into two sub-samples, divided by apparent magnitude, thus average redshift. From this early data we do not detect significant evolution in galaxy dark matter halo mass-to-light ratios from a redshift of 0.45 to 0.27. Finally, we test for non-spherical galaxy dark matter halos. Our results favor a dark matter halo with an ellipticity of ~0.3 at the 2-sigma level when averaged over all galaxies. If the sample of foreground lens galaxies is selected to favor ellipticals, the mean halo ellipticity and significance of this result increase.Comment: 12 pages, 11 figures, accepted to ApJ, uses emulateap

Properties of galaxy dark matter halos from weak lensing

We present the results of a study of weak lensing by galaxies based on 45.5 deg$^2$ of $R_C$ band imaging data from the Red-Sequence Cluster Survey (RCS). We present the first weak lensing detection of the flattening of galaxy dark matter halos. We use a simple model in which the ellipticity of the halo is $f$ times the observed ellipticity of the lens. We find a best fit value of $f=0.77^{+0.18}_{-0.21}$, suggesting that the dark matter halos are somewhat rounder than the light distribution. The fact that we detect a significant flattening implies that the halos are well aligned with the light distribution. Given the average ellipticity of the lenses, this implies a halo ellipticity of $=0.33^{+0.07}_{-0.09}$, in fair agreement with results from numerical simulations of CDM. This result provides strong support for the existence of dark matter, as an isotropic lensing signal is excluded with 99.5% confidence. We also study the average mass profile around the lenses, using a maximum likelihood analysis. We consider two models for the halo mass profile: a truncated isothermal sphere (TIS) and an NFW profile. We adopt observationally motivated scaling relations between the lens luminosity and the velocity dispersion and the extent of the halo. The best fit NFW model yields a mass $M_{200}=(8.4\pm0.7\pm0.4)\times 10^{11} h^{-1} M_\odot$ and a scale radius $r_s=16.2^{+3.6}_{-2.9} h^{-1}$ kpc. This value for the scale radius is in excellent agreement with predictions from numerical simulations for a halo of this mass.Comment: Significantly revised version, accepted for publication in ApJ 11 pages, 6 figure