David Calhoun

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OBJECTIVE PD may be caused by genetic susceptibility to neurotoxins. CYP2D6 is a candidate gene for PD because it regulates drug and toxin metabolism, but association studies have been inconsistent. The aim of this study was to test if the CYP2D6*4 allele (poor metabolizer phenotype) is associated with earlier age at onset. METHODS Five hundred(More)
—With the extraordinary growth in parallelism at all system scales driven by multicore architectures, computing performance is increasingly determined by how efficiently high-bandwidth data is communicated among the numerous compute resources. High-performance systems are especially challenged by the growing energy costs dominated by data movement. As(More)
  • Dessislava Nikolova, Sébastien Rumley, David Calhoun, Qi Li, Robert Hendry, Payman Samadi +209 others
  • 2015
With the rapidly increasing aggregate bandwidth requirements of data centers there is a growing interest in the insertion of optically interconnected networks with high-radix transparent optical switch fabrics. Silicon photonics is a particularly promising and applicable technology due to its small footprint, CMOS compatibility, high bandwidth density, and(More)
—Optical interconnects, which support the transport of large bandwidths over warehouse-scale distance, can help to further scale data-movement capabilities in high performance computing (HPC) platforms. However, due to the circuit switching nature of optical systems and additional peculiarities, such as sensitivity to temperature and the need for wavelength(More)
—Silicon photonic interconnection networks can provide significant advantages in bandwidth densities and data communication energy efficiencies over electronic-interconnected systems. However, due to the circuit switched nature of photonics, the latencies associated with circuit setup and reconfiguration must be managed to avoid added delays in application(More)
We test a high-resolution wave-propagation algorithm for hyperbolic conservation laws on mapped quadrilateral and hexahedral grids in the context of adaptive mesh refinement. We discuss some of the issues related to using non-Cartesian grids with AMR and study a test problem in which a grid refinement interface is fixed in space on a highly skewed portion(More)
Two patients with hyperparathyroidism had symmetric calcification of the brain, including the basal ganglia. In both patients, the neurologic disorder included parkinsonism and gait apraxia. Computerized tomography may help define the prevalence and clinical manifestations of this rare syndrome.
—iOS is Apple's mobile operating system and is presently used on the iPhone, iPad, and iPod Touch. The hardware platforms associated with the iOS operating system provide a powerful platform for sensor applications. In this paper, we provide a case study on the development of a digital multimeter (DMM) using an iPod Touch. The DMM case study addresses the(More)