3,657 research outputs found
On GROUSE and Incremental SVD
GROUSE (Grassmannian Rank-One Update Subspace Estimation) is an incremental
algorithm for identifying a subspace of Rn from a sequence of vectors in this
subspace, where only a subset of components of each vector is revealed at each
iteration. Recent analysis has shown that GROUSE converges locally at an
expected linear rate, under certain assumptions. GROUSE has a similar flavor to
the incremental singular value decomposition algorithm, which updates the SVD
of a matrix following addition of a single column. In this paper, we modify the
incremental SVD approach to handle missing data, and demonstrate that this
modified approach is equivalent to GROUSE, for a certain choice of an
algorithmic parameter
Experimental generation of multi-photon Fock states
We experimentally demonstrate the generation of multi-photon Fock states with
up to three photons in well-defined spatial-temporal modes synchronized with a
classical clock. The states are characterized using quantum optical homodyne
tomography to ensure mode selectivity. The three-photon Fock states are
probabilistically generated by pulsed spontaneous parametric down conversion at
a rate of one per second, enabling complete characterization in 12 hours.Comment: 9 pages, 5 figure
[Papers from the Special Session in Honor of Erving Goffman (Professor at the University of Pennsylvania 1968-1982)] Non-verbal navigational tools of conversation
High-Content Imaging for Large-Scale Detection of Low-Affinity Extracellular Protein Interactions.
Extracellular protein interactions coordinate cellular responses with their local environment and have important roles in pathogen invasion and disease. Due to technical challenges associated with studying binding events at the cell surface, the systematic and reliable identification of novel ligand-receptor pairs remains difficult. Here, we describe the development of a cell-based assay using large-scale transient transfections and high-content imaging (HCI) to detect extracellular binding events. We optimized the parameters for efficient transfection of human cells with cDNA plasmids encoding full-length cell surface receptors in 384-well plates. Using a range of well-characterized structurally diverse low-affinity cell surface interactions, we show that transfected cells probed with highly avid ligands can be used to successfully identify ligand-receptor pairs using an HCI platform and automated image analysis software. To establish the high-throughput potential of this approach, we also screened a pool of ligands against a collection of 2455 cell surface expression clones and found that known ligand-receptor interactions could be robustly and consistently detected across the library using this technology
- …