Search results for " array"
showing 10 items of 895 documents
RNA-Seq Atlas—a reference database for gene expression profiling in normal tissue by next-generation sequencing
2012
Abstract Motivation: Next-generation sequencing technology enables an entirely new perspective for clinical research and will speed up personalized medicine. In contrast to microarray-based approaches, RNA-Seq analysis provides a much more comprehensive and unbiased view of gene expression. Although the perspective is clear and the long-term success of this new technology obvious, bioinformatics resources making these data easily available especially to the biomedical research community are still evolving. Results: We have generated RNA-Seq Atlas, a web-based repository of RNA-Seq gene expression profiles and query tools. The website offers open and easy access to RNA-Seq gene expression pr…
Structure Learning in Nested Effects Models
2007
Nested Effects Models (NEMs) are a class of graphical models introduced to analyze the results of gene perturbation screens. NEMs explore noisy subset relations between the high-dimensional outputs of phenotyping studies, e.g., the effects showing in gene expression profiles or as morphological features of the perturbed cell. In this paper we expand the statistical basis of NEMs in four directions. First, we derive a new formula for the likelihood function of a NEM, which generalizes previous results for binary data. Second, we prove model identifiability under mild assumptions. Third, we show that the new formulation of the likelihood allows efficiency in traversing model space. Fourth, we…
Efficient change point detection in genomic sequences of continuous measurements
2010
Abstract Motivation: Knowing the exact locations of multiple change points in genomic sequences serves several biological needs, for instance when data represent aCGH profiles and it is of interest to identify possibly damaged genes involved in cancer and other diseases. Only a few of the currently available methods deal explicitly with estimation of the number and location of change points, and moreover these methods may be somewhat vulnerable to deviations of model assumptions usually employed. Results: We present a computationally efficient method to obtain estimates of the number and location of the change points. The method is based on a simple transformation of data and it provides re…
A novel digital control for DC/DC converters to improve steady-state performances
2006
This paper describes an innovative digital PWM control implementation for low voltage, high current DC-DC converters. The proposed technique, based on the use of a low resolution DAC, improves steady-state performances, minimizing limit cycle effects. The novel technique is tested on a FPGA-based single phase buck converter operating at 250 kHz. A detailed description of the proposed architecture is given and test results, simulation and experimental ones, are shown
The kinematics of water masers in the stellar molecular outflow source, IRAS 19134+2131
2004
Using the Very Large Array (VLA) and the Very Long Baseline Array (VLBA), we have observed water maser emission in the proto-planetary nebula candidate IRAS 19134+2131, in which the water maser spectrum has two groups of emission features separated in radial velocity by ∼100 km s^−1. The blue-shifted and red-shifted clusters of maser features are clearly separated spatially by ∼150 mas, indicative of a fast collimated flow. However, not all of the maser features are aligned along the axis of the flow, as is seen in the similar high-velocity water maser source, W43A. Comparing the VLA and VLBA maps of the water maser source, we find 4 maser features that were active for 2 years. Using only V…
Synthesis of a Linear Assembly Consisting of a Central Ru(Phen)32+ Derivative and Two Peripheral Porphyrins
2002
A ruthenium(II) precursor complex containing a bis-phenanthroline ligand, leading to a controlled helical structure around the metal centre, and a third phenanthroline-type ligand has been prepared. The spatial arrangement of the system is such that two chemical groups are disposed trans to one another on an axis running through the Ru centre. By appropriate functional group transformation, these two groups can be attached to monosubstituted zinc(II) porphyrins (PZn) to afford a linear array consisting of a central ruthenium(II) complex and two peripheral PZn motifs. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)
High gain/bandwidth off-chip antenna loaded with metamaterial unit-cell impedance matching circuit for sub-terahertz near-field electronic systems
2022
An innovative of-chip antenna (OCA) is presented that exhibits high gain and efciency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance bandwidth is enhanced by a factor of two and its gain on average by about 4 dB. Unlike conventional antennas, where the energy is dissipated in a resistive load, the technique proposed here signifcantly reduces losses. The antenna is excited from underneath the anten…
From microscopic to macroscopic description of Josephson dynamics in one-dimensional arrays of weakly-coupled superconducting islands
2015
Abstract By starting from a microscopic quantum mechanical description of Josephson dynamics of a one-dimensional array of N coupled superconductors, we obtain a set of linear differential equations for the system order parameter and for additional macroscopic physical quantities. With opportune considerations, we adapt this description to two coupled superconductors, obtaining the celebrated Feynman model for Josephson junctions. These results confirm the correspondence between the microscopic picture and the semi-classical Ohta’s model adopted in describing the superconducting phase dynamics in multi-barrier Josephson junctions.
The Saccharomyces cerevisiae flavodoxin-like proteins Ycp4 and Rfs1 play a role in stress response and in the regulation of genes related to metaboli…
2011
SPI1 is a gene whose expression responds to many environmental stimuli, including entry into stationary phase. We have performed a screening to identify genes that activate SPI1 promoter when overexpressed. The phosphatidylinositol- 4-phosphate 5-kinase gene MSS4 was identified as a positive activator of SPI1. Another SPI1 transcriptional regulator isolated was the flavodoxin-like gene YCP4. YCP4 and its homolog RFS1 regulate the expression of many genes during the late stages of growth. The double deletion mutant in YCP4 and its homolog RFS1 has an impact on gene expression related to metabolism by increasing the expression of genes involved in hexose transport and glycolysis, and decreasi…
Power Bus Management Techniques for Space Missions in Low Earth Orbit
2021
In space vehicles, the typical configurations for the Solar Array Power Regulators in charge of managing power transfer from the solar array to the power bus are quite different from the corresponding devices in use for terrestrial applications. A thorough analysis is reported for the most popular approaches, namely Sequential Switching Shunt Regulation and parallel-input Pulse Width Modulated converters with Maximum Power Point Tracking. Their performance is compared with reference to a typical mission in low Earth orbit, highlighting the respective strengths and weaknesses. A novel solar array managing technique, the Sequential Maximum Power Tracking, is also introduced in the trade-off a…