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Quantum error correction is essential for realizing the full potential of large-scale quantum information processing devices.sup.1,2. Fundamental to its experimental realization is the repetitive detection of errors via projective measurements of quantum correlations among qubits, as well as corrections using conditional feedback.sup.3. Repetitive application of such tasks requires that they neither induce unwanted crosstalk nor impede further control operations, which is challenging owing to the need to dissipatively couple qubits to the classical world for detection and reinitialization. For trapped ions, state readout involves scattering large numbers of resonant photons, which increases the probability of stray light causing errors on nearby qubits and leads to undesirable recoil heating of the ion motion. Here we demonstrate up to 50 sequential measurements of correlations between two beryllium ion microwave qubits using an ancillary optical qubit in a calcium ion, and implement feedback that allows us to stabilize two-qubit subspaces as well as Bell states, a class of maximally entangled states. Multi-qubit mixed-species gates are used to transfer information within the register from the qubit to the ancilla, enabling readout with negligible crosstalk to the data qubits. Heating of the ion motion during detection is mitigated by recooling all three ions using light that interacts with only the calcium ion, known as sympathetic cooling. A key element of our experimental setup is a powerful classical control system that features flexible in-sequence processing for feedback control. The methods employed here provide essential tools for scaling trapped-ion quantum computing, quantum-state control and entanglement-enhanced quantum metrology.sup.4.A multi-qubit mixed-species register is used for repeated correlation measurements using conditional feedback to stabilize two-qubit subspaces and Bell states, achieving up to 50 sequential measurements with negligible crosstalk., Author(s): V. Negnevitsky [sup.1] , M. Marinelli [sup.1] , K. K. Mehta [sup.1] , H.-Y. Lo [sup.1] , C. Flühmann [sup.1] , J. P. Home [sup.1] Author Affiliations:(1) Institute for [...]

Students listened to abstract words in context sentences while viewing pictures with and without embedded words to concurrently examine dual coding theory and the split attention effect. Results suggested that the dual coding conditions (the two element condition and the three element condition) were more effective at teaching abstract words than simply reading words in context sentences (one element). However, the benefits of using dual coding only facilitated transfer when the word was embedded into the picture (three element condition), demonstrating a split attention effect. Practical implications are noted., INTRODUCTION Work by Arlin, Scott, and Webster (1978) long established that seeing a word with a picture is 44% more effective than hearing a word with a picture. Dual coding [...]

Spatial-domain design for wavefront-coding systems frequently simplifies the defining oscillatory integral of the point spread function (PSF) by means of the stationary phase approximation (SPA). Although the SPA applies over much of the support of the PSF, it tends to break down at or near the regions of highest intensity. A branch of mathematics known as catastrophe theory is shown to provide tools that can ferret out important design information precisely at the points where the SPA is unphysical. [c] 2010 Optical Society of America OCIS codes: 110.1758, 110.0110, 070.0070.

A coded aperture snapshot spectral imager (CASSI) estimates the three-dimensional spatiospectral data cube from a snapshot two-dimensional coded projection, assuming that the scene is spatially and spectrally sparse. For less spectrally sparse scenes, we show that the use of multiple nondegenerate snapshots can make data cube recovery less ill-posed, yielding improved spatial and spectral reconstruction fidelity. Additionally, data acquisition can be easily scaled to meet the time/resolution requirements of the scene with little modification or extension of the original CASSI hardware. A multiframe reconstruction of a 640 x 480 x 53 voxel datacube with 450-650 nm white-light illumination of a scene reveals substantial improvement in the reconstruction fidelity, with limited increase in acquisition and reconstruction time. [c] 2010 Optical Society of America OCIS codes: 110.4155, 110.4190, 110.4234, 120.6200.

VTDIRECT95 is a Fortran 95 implementation of D. R. Jones' deterministic global optimization algorithm called DIRECT, which is widely used in multidisciplinary engineering design, biological science, and physical science applications. The package includes both a serial code and a data-distributed massively parallel code for different problem scales and optimization (exploration vs. exploitation) goals. Dynamic data structures are used to organize local data, handle unpredictable memory requirements, reduce the memory usage, and share the data across multiple processors. The parallel code employs a multilevel functional and data parallelism to boost concurrency and mitigate the data dependency, thus improving the load balancing and scalability. In addition, checkpointing features are integrated into both versions to provide fault tolerance and hot restarts. Important algorithm modifications and design considerations are discussed regarding data structures, parallel schemes, error handling, and portability. Using several benchmark functions and real-world applications, the software is evaluated on different systems in terms of optimization effectiveness, data structure efficiency, parallel performance, and checkpointing overhead. The package organization and usage are also described in detail. Categories and Subject Descriptors: J.2 [Physical Science and Engineering]: Mathematics and Statistics; G.4 [Mathematical Software] General Terms: Algorithms, Design, Documentation Additional Key Words and Phrases: DIRECT, global optimization, data structures, parallel schemes, checkpointing DOI 10.1145/1527286.1527291

MicroRNAs (miRNAs) are a class of short noncoding RNAs that regulate protein-coding genes posttranscriptionally. In animals, most known miRNA targeting occurs within the 3'UTR of mRNAs, but the extent of biologically relevant targeting in the ORF or 5' UTR of mRNAs remains unknown. Here, we develop an algorithm (MinoTar--miRNA ORF Targets) to identify conserved regulatory motifs within protein-coding regions and use it to estimate the number of preferentially conserved miRNA-target sites in ORFs. We show that, in Drosophila, preferentially conserved miRNA targeting in ORFs is as widespread as it is in 3'UTRs and that, while far less abundant, conserved targets in Drosophila 5'UTRs number in the hundreds. Using our algorithm, we predicted a set of high-confidence ORF targets and selected seven miRNA-target pairs from among these for experimental validation. We observed down-regulation by the miRNA in five out of seven cases, indicating our approach can recover functional sites with high confidence. Additionally, we observed additive targeting by multiple sites within a single ORF. Altogether, our results demonstrate that the scale of biologically important miRNA targeting in ORFs is extensive and that computational tools such as ours can aid in the identification of such targets. Further evidence suggests that our results extend to mammals, but that the extent of ORF and 5'UTR targeting relative to 3'UTR targeting may be greater in Drosophila. comparative genomics | target prediction doi/ 10.1073/pnas.1006172107