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We use heat kernels or eigenfunctions of the Laplacian to construct local coordinates on large classes of Euclidean domains and Riemannian manifolds (not necessarily smooth, e.g., with (alpha) metric). These coordinates are bi-Lipschitz on large neighborhoods of the domain or manifold, with constants controlling the distortion and the size of the(More)
present a randomized algorithm for the approximate nearest neighbor problem in d-dimensional Euclidean space. Given N points {x j } in R d , the algorithm attempts to find k nearest neighbors for each of x j , where k is a user-specified integer parameter. The algorithm is iterative, and its CPU time requirements are proportional to T · N · (d · (log d) + k(More)
The Lobula Giant Movement Detector (LGMD) is a higher-order visual interneuron of Orthopteran insects that responds preferentially to objects approaching on a collision course. It receives excitatory input from an entire visual hemifield that anatomical evidence suggests is retinotopic. We show that this excitatory projection activates calcium-permeable(More)
Noise is a major concern in circuits processing electrical signals, including neural circuits. There are many factors that influence how noise propagates through neural circuits, and there are few systems in which noise levels have been studied throughout a processing pathway. We recorded intracellularly from multiple stages of a sensory-motor pathway in(More)
BACKGROUND AND PURPOSE Patients who have had a stroke are at risk of hypoxia through alterations in the central regulation of respiration, through aspiration, and through respiratory muscle weakness. Sleep-related breathing disorders are common and may lead to episodes of nocturnal hypoxia even when daytime oxygenation is normal. The aim of this study was(More)
This study investigated potential differences in the cutting of mediolateral episiotomy between doctors and midwives. Depth, length, distance from midline and shortest distance from the midpoint of the anal canal to the episiotomy were measured in a sample of primigravid women. The angle subtended from the sagittal or parasagittal plane was calculated. Two(More)
OBJECTIVE To investigate multimorbidity transitions from general practice populations across healthcare interfaces and the associated healthcare costs. DESIGN Clinical-linkage database study. SETTING Population (N=60 660) aged 40 years and over registered with 53 general practices in Stoke-on-Trent. PARTICIPANTS Population with six specified(More)
How higher-order sensory neurons generate complex selectivity from their simpler inputs is a fundamental question in neuroscience. The lobula giant movement detector (LGMD) is such a visual neuron in the locust Schistocerca americana that responds selectively to objects approaching on a collision course or their two-dimensional projections, looming stimuli(More)
OBJECTIVE To assess the repeatability and validity of the electromagnetic 3-dimensional tracking system, Fastrak, in measuring cervical spine and shoulder movement in patients with ankylosing spondylitis (AS). METHODS Fifty patients with AS had their cervical spine and shoulder movements measured on up to 3 occasions with the Fastrak. Patients also(More)