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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)
Neurons in a variety of species, both vertebrate and invertebrate, encode the kinematics of objects approaching on a collision course through a time-varying firing rate profile that initially increases, then peaks, and eventually decays as collision becomes imminent. In this temporal profile, the peak firing rate signals when the approaching object's(More)
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)
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)
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 induction of secretory and inflammatory responses in calves by Salmonella typhimurium and Salmonella dublin strains was compared, and the effects of mutations in the invH and stn genes were assessed. S. typhimurium induced greater secretory and inflammatory responses than S. dublin in bovine ileal loops, despite the fact that these serotypes were(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)
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)
Salmonella typhimurium 4/74 is highly virulent for cattle after oral challenge, causing severe diarrhoea, which is sometimes associated with systemic spread of the micro-organism. Although susceptible to oral challenge, groups of cattle were found to be relatively resistant to subcutaneous challenge with this strain. The virulence of S. typhimurium 4/74(More)