24 research outputs found

    Fractal phenomena in fracture

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    Bielschowsky head-tilt test-I. Ocular counterrolling and Bielschowsky head-tilt test in 23 cases of superior oblique palsy

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    We have measured the amplitude of ocular counterrolling (OCR) and the change in vertical deviation in the Bielschowsky head-tilt test (BHT) in 23 cases of unilateral superior oblique palsy. OCR was measured with a photographical method, using limbal, conjunctival vessels as landmarks. Average OCR of the healthy eye was 5.4 ± 2.4 (SD) deg either side, at 45 deg of body-tilt. BHT and OCR (of the healthy eye) were not related in the group as a whole. An important perturbing factor was the duration of the palsy. To clarify the relation between BHT, OCR and duration of palsy, the BHT/OCR ratio was calculated in each patient. Six cases with a palsy of presumed recent onset had BHT/OCR ratio of 0.57 ± 0.09, while twelve cases of long-standing palsy had a BHT/OCR ratio of 1.04 ± 0.71. This means that in cases of recent onset, the relation was relatively fixed. All high BHT/OCR ratio's occurred in long-standing palsies, whether acquired or congenital. In our opinion, disproportionately large amplitudes in the Bielschowsky head-tilt test are caused by secondary innervational changes or contractures

    Cellular magnetic devices : using magnetostatically interacting elements for logic, memory, and communication

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    Control of domain wall pinning by switchable nanomagnet state

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    We report on a novel approach to establish switchable pinning of magnetic domain walls in a nanowire with perpendicular magnetic anisotropy by a single in-plane magnetized single-domain nanomagnet positioned on top of the wire. Devices were prepared by depositing a permalloy nanomagnet on top of a nanowire formed from a Co/Ni multilayer with their long axes parallel, separated by a nonmagnetic layer. We show by electrical measurements that the domain wall pinning strength depends critically on the state of the bistable nanomagnet and can differ by more than 10¿mT. We also performed micromagnetic calculations that show that the difference in pinning strength is caused by the interaction of the forced Néel wall with the nanomagnet's magnetostatic field

    100 Long-Distance Triathlons in 100 Days: A Case Study on Ultraendurance, Biomarkers, and Physiological Outcomes.

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    The physical demands of a single long-distance triathlon (LDT) are sufficient to cause robust physiological perturbations. In this unique case study, an ultraendurance athlete completed 100 LDTs in 100 days (100LDT). PURPOSE: This study aims to describe and analyze this single athlete's performance, physiological biomarkers, and sleep parameters throughout the 100LDT. METHODS: An ultraendurance athlete completed an LDT (2.4-mile swim, 112-mile bike ride, and 26.2-mile marathon) each day for 100 consecutive days. Physical work, physiological biomarkers, and sleep parameters were recorded each night using a wrist-worn photoplethysmographic sensor. Clinical exercise tests were performed before and after the 100LDT. Time-series analysis assessed changes in biomarkers and sleep parameters across the 100LDT, and cross-correlations considered the associations between exercise performance and physiological metrics at varying time lags. RESULTS: The swim and cycling performances varied across the 100LDT, while the run was relatively stable. Resting heart rate, heart-rate variability, oxygen saturation, sleep score, light sleep, sleep efficiency, and sleep duration were all best characterized by cubic models. Additional post hoc subanalyses suggest that the first half of the 100LDT most influenced these dynamics. CONCLUSIONS: The 100LDT resulted in nonlinear alterations to physiological metrics. This world record was a unique event but allows valuable insights into the limits of human endurance performance
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