In a geometric context, two objects are “visible” to each other if there is a line segment connecting them that does not cross any obstacles. Over 500 papers have been published on aspects of visibility in computational geometry in the last 40 years. The research can be broadly classified as primarily focused on combinatorial issues, or primarily focused on algorithms. We partition the combinat...

Bronchiolitis, a disease primarily of the first 2 years of life charac­ terized by signs and symptoms of obstructive airway disease, is caused most commonly by viruses. Approximately 2% to 3% of infants in the first 12 months of life are hospitalized with bron­ chiolitis, accounting for approximately 125,000 hospitalizations and 200 to 500 deaths annually in the United States. Data from the Cen...

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Objective: To report a case of subependymal giant cell astrocytoma (SEGA) in a patient with tuberous sclerosis, emphasizing the proton MR spectroscopy (MRS) findings. Case: A three year-old boy with tuberous sclerosis presented with a 3-month history of mild headache. The physical examination showed discrete mental retardation and multiple hypomelanic macules in the legs and back. MRI showed ma...