In vivo NMR as a tool for probing molecular structure and dynamics in intact Chlamydomonas reinhardtii cells

Article / Letter to editorLeiden Institute of Chemistry;Leiden Institute of Chemistr

Frequency Offset Correction in a Software Defined HiperLAN/2 Demodulator using Preamble Section A

In our Software Defined Radio project we perform a feasibility study of a software defined radio for two communication standards: HiperLAN/2 and Bluetooth. In this paper the Matlab/Simulink implementation of the HiperLAN/2 demodulator for the demonstrator of the project is discussed, with special attention for the frequency offset corrector. This type of correction is necessary to prevent large bit error rates that are caused by inter-subcarrier interference. The method that is proposed in this paper uses preamble section A to estimate the frequency offset. Simulation results for an AWGN channel show that the method is capable of correcting frequency offsets up to the boundary defined in the standard [1]. It was observed that frequency offset correction using only preamble section A is sensitive to ¿for example¿ synchronization errors in case real-life analog front-end signals are used

In vivo NMR as a tool for probing molecular structure and dynamics in intact Chlamydomonas reinhardtii cells

Article / Letter to editorLeiden Institute of Chemistry;Leiden Institute of Chemistr

In vivo NMR as a tool for probing molecular structure and dynamics in intact Chlamydomonas reinhardtii cells

Article / Letter to editorLeiden Institute of Chemistry;Leiden Institute of Chemistr

Do rehabilitation patients with chronic low back pain meet World Health Organisation's recommended physical activity levels?

Purpose: Primary: to analyse the time that patients with chronic low back pain (CLBP) admitted to pain rehabilitation spent on moderate to vigorous physical activity (MVPA) and compare this to the WHO recommen-dations. Secondary: to explore factors that might differentiate between those who do and do not meet the recommendations. Materials and methods: A Cross-sectional study embedded in secondary interdisciplinary rehabilitation of adults with CLBP. PA was measured with a tri-axial accelerometer for 1 week during admission phase. Time spent in each PA level was calculated. MVPA was also analysed in >= 10 min bouts. Results: Complete datasets of 4-6 days recorded accelerometery of n = 46 patients were analysed. Time spent in MVPA was on average 6.0% per day. MVPA per day in >= 10-min bouts occurred on average 0.8 times per day (sd = 0.9; min-max 0-4). Percentage of patients meeting the recommended level of MVPA was 21.7% (10/46) and 84.8% (39/46) for the 2010 and 2020 recommendations, respectively. Most demographic and clinical variables did not seem to differentiate between those who met the WHO recommendations, and those who did not. Conclusion: The minority of the patients (22%) met the WHO recommended MVPA level of 2010. The more lenient recommendation of 2020 was met by 85%

Dosage of pain rehabilitation programmes for patients with chronic musculoskeletal pain:a non-inferiority randomised controlled trial

PURPOSE: To analyse the effects of interdisciplinary pain rehabilitation programmes with different dosages; care as usual versus short form. METHODS: A single blinded, two armed, randomised controlled trial, with non-inferiority design was performed. All patients with chronic musculoskeletal pain referred to an outpatient multidisciplinary pain rehabilitation programme were eligible for this study. Only dosage differed, content was similar. The difference on Pain Disability Index was the primary outcome measure. Four points difference on Pain Disability Index was applied as a non-inferiority margin. Treatment effects within groups were expressed in standardised mean difference and effect sizes were calculated between the groups. RESULTS: Because care as usual was frequently extended, the difference in dosage between groups was limited. The study was stopped prematurely because of an a-priori stopping rule. Interim analyses are presented. Both groups (care as usual n = 58, short form n = 54) improved significantly (mean Pain Disability Index change care as usual: -10.8; short form: -8.3). Mean difference between groups was 2.5 points (95% confidence interval was -2.2 to 7.3). Effect size between groups was 0.2. CONCLUSIONS: The 95% confidence interval for the difference in mean pain disability reduction exceeded the upper limit of the non-inferiority margin. The results of the primary analyses of this trial are, therefore, inconclusive. Ancillary analyses revealed that programme dosage was not associated with differences in the disability outcomes. Implications for rehabilitation Optimum dosage of interdisciplinary pain rehabilitation programs is unknown and scarcely studied. This study is the first to analyse dosage as primary aim. Although results are inconclusive, they also suggest that differences in dosage may not automatically lead to differences in effects. Further research is needed to analyse what dosage works for whom; to detect optimum effective and cost-effective dosage of pain rehabilitation programmes

Electronic structure of the candidate 2D Dirac semimetal SrMnSb2: a combined experimental and theoretical study

SrMnSb$_2$ is suggested to be a magnetic topological semimetal. It contains square, 2D Sb planes with non-symmorphic crystal symmetries that could protect band crossings, offering the possibility of a quasi-2D, robust Dirac semi-metal in the form of a stable, bulk (3D) crystal. Here, we report a combined and comprehensive experimental and theoretical investigation of the electronic structure of SrMnSb$_2$, including the first ARPES data on this compound. SrMnSb$_2$ possesses a small Fermi surface originating from highly 2D, sharp and linearly dispersing bands (the Y-states) around the (0,$\pi$/a)-point in $k$-space. The ARPES Fermi surface agrees perfectly with that from bulk-sensitive Shubnikov de Haas data from the same crystals, proving the Y$-$states to be responsible for electrical conductivity in SrMnSb$_2$. DFT and tight binding (TB) methods are used to model the electronic states, and both show good agreement with the ARPES data. Despite the great promise of the latter, both theory approaches show the Y-states to be gapped above E$_F$, suggesting trivial topology. Subsequent analysis within both theory approaches shows the Berry phase to be zero, indicating the non-topological character of the transport in SrMnSb$_2$, a conclusion backed up by the analysis of the quantum oscillation data from our crystals.Comment: 26 pages, 10 figures, revised submission to SciPost after including changes requested by referees. All referee reports are open and can be viewed here: https://scipost.org/submissions/1711.07165v2

Embodied conversations: Performance and the design of a robotic dancing partner

This paper reports insights gained from an exploration of performance-based techniques to improve the design of relationships between people and responsive machines. It draws on the Emergent Objects project and specifically addresses notions of embodiment as employed in the field of performance as a means to prototype and develop a robotic agent, SpiderCrab, designed to promote expressive interaction of device and human dancer, in order to achieve ‘performative merging’. The significance of the work is to bring further knowledge of embodiment to bear on the development of human-technological interaction in general. In doing so, it draws on discursive and interpretive methods of research widely used in the field of performance but not yet obviously aligned with some orthodox paradigms and practices within design research. It also posits the design outcome as an ‘objectile’ in the sense that a continuous and potentially divergent iteration of prototypes is envisaged, rather than a singular final product. The focus on performative merging draws in notions of complexity and user experience. Keywords: Embodiment; Performance; Tacit Knowledge; Practice-As-Research; Habitus.</p