17 research outputs found
Vanishing tilt-to-length coupling for a singular case in two-beam laser interferometers with Gaussian beams
The omnipresent tilt-to-length coupling in two-beam laser interferometers,
frequently a nuisance in precision measurements, vanishes for the singular case
of two beams with identical parameters and complete detection of both beams
without clipping. This effect has been observed numerically and is explained in
this manuscript by the cancellation of two very different effects of equal
magnitude and opposite sign.
This paper was published in Applied Optics and is made available as an
electronic reprint with the permission of OSA. The paper can be found at the
following URL on the OSA website:
[http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-54-5-1010]. Systematic or
multiple reproduction or distribution to multiple locations via electronic or
other means is prohibited and is subject to penalties under law
Feasibility of an individualised, task-oriented, video-supported home exercise programme for arm function in patients in the subacute phase after stroke: protocol of a randomised controlled pilot study
INTRODUCTION
Stroke rehabilitation guidelines suggest a high-frequency task-oriented training at high intensity. A targeted and self-paced daily training with intermittent supervision is recommended to improve patients' self-management and functional output. So far, there is conflicting evidence concerning the most effective home-training delivery method.
METHODS AND ANALYSIS
The purpose of this pilot study is to compare the feasibility and preliminary effects of task-oriented home-exercises in patients in the subacute stage after stroke. Twenty-four patients will be randomised (1:1) to a Video group (a) or Paper group (b) of an individualised, task-oriented home-training (50âmin, 6Ă/week, for 4 weeks) based on Wulf and Lewthwaite's Optimizing Performance Through Intrinsic Motivation and Attention for Learning theory of motor learning. Patient-relevant goals will be identified using Goal Attainment Scaling and exercises progressively adapted. Semistructured interviews and a logbook will be used to monitor adherence, arm use and acceptability. Primary outcome will be the feasibility of the methods and a full-scale trial employing predefined feasibility criteria (recruitment, retention and adherence rates, patients' satisfaction with the home-exercise programme and their progress, affected hand use and acceptance of the intervention). Assessed at baseline, post intervention and 4-week follow-up, secondary outcomes include self-perceived hand and arm use, actual upper extremity function and dexterity, hand strength, independence in activities of daily living and health-related quality of life. Interview data will be analysed using qualitative content analysis. Medians (ranges) will be reported for ordinal data, means (SD) for continuous and frequency (percentage) for nominal data.
ETHICS AND DISSEMINATION
This study follows the Standard Protocol Items: Recommendations for Interventional Trials-Patient-Reported Outcome (PRO) Extension guideline. Ethical approval was received from the Ethics Committee of the Medical University of Innsbruck, Austria (1304/2020). Written informed consent will be obtained from all participants prior to data collection. Study results will be disseminated to participating patients, patient organisations, via the clinic's homepage, relevant conferences and peer-reviewed journals.
TRIAL REGISTRATION NUMBER
DRKS-ID: DRKS00023395.Study protocol, second revision, 5 December 2021
Laser Interferometer Space Antenna
Following the selection of The Gravitational Universe by ESA, and the
successful flight of LISA Pathfinder, the LISA Consortium now proposes a 4 year
mission in response to ESA's call for missions for L3. The observatory will be
based on three arms with six active laser links, between three identical
spacecraft in a triangular formation separated by 2.5 million km.
LISA is an all-sky monitor and will offer a wide view of a dynamic cosmos
using Gravitational Waves as new and unique messengers to unveil The
Gravitational Universe. It provides the closest ever view of the infant
Universe at TeV energy scales, has known sources in the form of verification
binaries in the Milky Way, and can probe the entire Universe, from its smallest
scales near the horizons of black holes, all the way to cosmological scales.
The LISA mission will scan the entire sky as it follows behind the Earth in its
orbit, obtaining both polarisations of the Gravitational Waves simultaneously,
and will measure source parameters with astrophysically relevant sensitivity in
a band from below Hz to above Hz.Comment: Submitted to ESA on January 13th in response to the call for missions
for the L3 slot in the Cosmic Vision Programm
Safety of intravenous ferric carboxymaltose versus oral iron in patients with nondialysis-dependent CKD: an analysis of the 1-year FIND-CKD trial.
Background: The evidence base regarding the safety of intravenous (IV) iron therapy in patients with chronic kidney disease (CKD) is incomplete and largely based on small studies of relatively short duration. Methods: FIND-CKD (ClinicalTrials.gov number NCT00994318) was a 1-year, open-label, multicenter, prospective study of patients with nondialysis-dependent CKD, anemia and iron deficiency randomized (1:1:2) to IV ferric carboxymaltose (FCM), targeting higher (400-600 ”g/L) or lower (100-200 ”g/L) ferritin, or oral iron. A post hoc analysis of adverse event rates per 100 patient-years was performed to assess the safety of FCM versus oral iron over an extended period. Results: The safety population included 616 patients. The incidence of one or more adverse events was 91.0, 100.0 and 105.0 per 100 patient-years in the high ferritin FCM, low ferritin FCM and oral iron groups, respectively. The incidence of adverse events with a suspected relation to study drug was 15.9, 17.8 and 36.7 per 100 patient-years in the three groups; for serious adverse events, the incidence was 28.2, 27.9 and 24.3 per 100 patient-years. The incidence of cardiac disorders and infections was similar between groups. At least one ferritin level â„800 ”g/L occurred in 26.6% of high ferritin FCM patients, with no associated increase in adverse events. No patient with ferritin â„800 ”g/L discontinued the study drug due to adverse events. Estimated glomerular filtration rate remained the stable in all groups. Conclusions: These results further support the conclusion that correction of iron deficiency anemia with IV FCM is safe in patients with nondialysis-dependent CKD
Tilt-to-length coupling in LISA Pathfinder: analytical modelling
Tilt-to-length coupling was the limiting noise source in LISA Pathfinder
between 20 and 200 mHz before subtraction in post-processing. To prevent the
adding of sensing noise to the data by the subtraction process, the success of
this strategy depended on a previous direct noise reduction by test mass
alignment. The exact dependency of the level of tilt-to-length coupling on the
set-points of LISA Pathfinder's test masses was not understood until the end of
the mission. Here, we present, for the first time, an analytical tilt-to-length
coupling model that describes the coupling noise changes due to the
realignments. We report on the different mechanisms, namely the lever arm and
piston effect as well as the coupling due to transmissive components, and how
they contribute to the full coupling. Further, we show that a pure geometric
model would not have been sufficient to describe the coupling in LISA
Pathfinder. Therefore, we model also the non-geometric tilt-to-length noise
contributions. For the resulting coupling coefficients of the full model, we
compute the expected error bars based on the known individual error sources.
Also, we validated the analytical model against numerical simulations. A
detailed study and thorough understanding of this noise are the basis for a
successful analysis of the LISA Pathfinder data with respect to tilt-to-length
coupling
Geometric tilt-to-length coupling in precision interferometry: mechanisms and analytical descriptions
Tilt-to-length coupling is a technical term for the cross-coupling of angular
or lateral jitter into an interferometric phase signal. It is an important
noise source in precision interferometers and originates either from changes in
the optical path lengths or from wavefront and clipping effects. Within this
paper, we focus on geometric TTL coupling and categorize it into a number of
different mechanisms for which we give analytic expressions. We then show that
this geometric description is not always sufficient to predict the TTL coupling
noise within an interferometer. We, therefore, discuss how understanding the
geometric effects allows TTL noise reduction already by smart design choices.
Additionally, they can be used to counteract the total measured TTL noise in a
system. The presented content applies to a large variety of precision
interferometers, including space gravitational wave detectors like LISA