Showing papers by "Raytheon published in 2010"

Multiangle Imaging SpectroRadiometer global aerosol product assessment by comparison with the Aerosol Robotic Network

Abstract: [1] A statistical approach is used to assess the quality of the Multiangle Imaging SpectroRadiometer (MISR) version 22 (V22) aerosol products. Aerosol optical depth (AOD) retrieval results are improved relative to the early postlaunch values reported by [Kahn et al. (2005)], which varied with particle type category. Overall, about 70% to 75% of MISR AOD retrievals fall within 0.05 or 20% × AOD of the paired validation data from the Aerosol Robotic Network (AERONET), and about 50% to 55% are within 0.03 or 10% x AERONET AOD, except at sites where dust or mixed dust and smoke are commonly found. Retrieved particle microphysical properties amount to categorical values, such as three size groupings: "small," "medium," and "large." For particle size, ground-based AERONET sun photometer Angstrom exponents are used to assess statistically the corresponding MISR values, which are interpreted in terms of retrieved size categories. Coincident single-scattering albedo (SSA) and fraction AOD spherical data are too limited for statistical validation. V22 distinguishes two or three size bins, depending on aerosol type, and about two bins in SSA (absorbing vs. nonabsorbing), as well as spherical vs. nonspherical particles, under good retrieval conditions. Particle type sensitivity varies considerably with conditions and is diminished for midvisible AODs below about 0.15 or 0.2. On the basis of these results, specific algorithm upgrades are proposed and are being investigated by the MISR team for possible implementation in future versions of the product.

The ACS Nearby Galaxy Survey Treasury. IX. Constraining Asymptotic Giant Branch Evolution with Old Metal-poor Galaxies

Abstract: In an attempt to constrain evolutionary models of the asymptotic giant branch (AGB) phase at the limit of low masses and low metallicities, we have examined the luminosity functions and number ratios between AGB and red giant branch (RGB) stars from a sample of resolved galaxies from the ACS Nearby Galaxy Survey Treasury. This database provides Hubble Space Telescope optical photometry together with maps of completeness, photometric errors, and star formation histories for dozens of galaxies within 4 Mpc. We select 12 galaxies characterized by predominantly metal-poor populations as indicated by a very steep and blue RGB, and which do not present any indication of recent star formation in their color-magnitude diagrams. Thousands of AGB stars brighter than the tip of the RGB (TRGB) are present in the sample (between 60 and 400 per galaxy), hence, the Poisson noise has little impact in our measurements of the AGB/RGB ratio. We model the photometric data with a few sets of thermally pulsing AGB (TP-AGB) evolutionary models with different prescriptions for the mass loss. This technique allows us to set stringent constraints on the TP-AGB models of low-mass, metal-poor stars (with M < 1.5 M_⊙, [Fe/H] ≾ -1.0). Indeed, those which satisfactorily reproduce the observed AGB/RGB ratios have TP-AGB lifetimes between 1.2 and 1.8 Myr, and finish their nuclear burning lives with masses between 0.51 and 0.55 M_⊙. This is also in good agreement with recent observations of white dwarf masses in the M4 old globular cluster. These constraints can be added to those already derived from Magellanic Cloud star clusters as important mileposts in the arduous process of calibrating AGB evolutionary models.

System and method for malware detection

Abstract: According to one embodiment, a computer-implemented method for execution on one or more processors includes receiving a first file and determining a file type of the first file. The method also includes determining, according to a first policy, a plurality of malware detection schemes to apply to the first file based on the determined file type of the first file. In addition, the method includes scheduling the application of the determined plurality of malware detection schemes to the first file amongst a plurality of detection nodes according to a second policy. Further, the method includes determining, in response to determining the results of applying the plurality of malware detection schemes, that the first file is malware or determining that the first file is suspected malware according to a third policy.

Wireless power transmission system and method

Abstract: A wireless power transmission system including at least one source of electromagnetic radiation, a plurality of wireless power receivers that receive radiated electromagnetic energy, a beacon collocated with each wireless power receiver, wherein the beacon generates and radiates a pilot signal when the beacon is in an active state, and an array of transmitting antennas connected to the source of electromagnetic radiation that radiates the electromagnetic radiation in the direction of the beacon in the active state. The electromagnetic radiation can be electronically steered from one wireless power receiver to another by activating and deactivating the beacons collocated with each wireless power receiver.

Mapping the stellar structure of the milky way thick disk and halo using segue photometry

Abstract: We map the stellar structure of the Galactic thick disk and halo by applying color-magnitude diagram (CMD) fitting to photometric data from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey. The SEGUE imaging scans allow, for the first time, a comprehensive analysis of Milky Way structure at both high and low latitudes using uniform Sloan Digital Sky Survey photometry. Incorporating photometry of all relevant stars simultaneously, CMD fitting bypasses the need to choose single tracer populations. Using old stellar populations of differing metallicities as templates, we obtain a sparse three-dimensional map of the stellar mass distribution at |Z|>1?kpc. Fitting a smooth Milky Way model comprising exponential thin and thick disks and an axisymmetric power-law halo allows us to constrain the structural parameters of the thick disk and halo. The thick-disk scale height and length are well constrained at 0.75 ? 0.07?kpc and 4.1 ? 0.4?kpc, respectively. We find a stellar halo flattening within ~25?kpc of c/a = 0.88 ? 0.03 and a power-law index of 2.75 ? 0.07 (for 7?kpc RGC 30?kpc). The model fits yield thick-disk and stellar halo densities at the solar location of ?thick,? = 10?2.3?0.1 M ??pc?3 and ?halo,? = 10?4.20?0.05 M ??pc?3, averaging over any substructures. Our analysis provides the first clear in situ evidence for a radial metallicity gradient in the Milky Way's stellar halo: within R 15?kpc the stellar halo has a mean metallicity of [Fe/H] ?1.6, which shifts to [Fe/H] ?2.2 at larger radii, in line with the two-component halo deduced by Carollo et?al. from a local kinematic analysis. Subtraction of the best-fit smooth and symmetric model from the overall density maps reveals a wealth of substructures at all latitudes, some attributable to known streams and overdensities, and some new. A simple warp cannot account for the low latitude substructure, as overdensities occur simultaneously above and below the Galactic plane.

The nature of starbursts. i. the star formation histories of eighteen nearby starburst dwarf galaxies

Abstract: We use archival Hubble Space Telescope observations of resolved stellar populations to derive the star formation histories (SFHs) of 18 nearby starburst dwarf galaxies. In this first paper, we present the observations, color-magnitude diagrams (CMDs), and the SFHs of the 18 starburst galaxies, based on a homogeneous approach to the data reduction, differential extinction, and treatment of photometric completeness. We adopt a star formation rate (SFR) threshold normalized to the average SFR of the individual system as a metric for classifying starbursts in SFHs derived from resolved stellar populations. This choice facilitates finding not only the currently bursting galaxies but also "fossil" bursts increasing the sample size of starburst galaxies in the nearby (D 100 Myr temporal baseline is thus fundamental to any starburst definition or identification method. The longer lived bursts rule out rapid "self-quenching" of starbursts on global scales. The bursting galaxies' gas consumption timescales are shorter than the Hubble time for all but one galaxy confirming the short-lived nature of starbursts based on fuel limitations. Additionally, we find that the strength of the Hα emission usually correlates with the CMD-based SFR during the last 4-10 Myr. However, in four cases, the Hα emission is significantly less than what is expected for models of starbursts; the discrepancy is due to the SFR changing on timescales of a few Myr. The inherently short timescale of the Hα emission limits identifying galaxies as starbursts based on the current characteristics which may or may not be representative of the recent SFH of a galaxy.

System and method for host-level malware detection

Abstract: According to one embodiment, a computer-implemented method includes: accessing a set of configuration parameters, accessing a set of identifiers of files known not to be malware, and accessing a set of identifiers of files known to be malware. Further, the method includes: comparing a first file to the set of configuration parameters, determining that a first hash of the first file is not in the set of identifiers of files known not to be malware and that the first hash is not in the set of identifiers of files known to be malware, and sending the at least one file and information related to the at least one file to be analyzed for malware. The method includes deleting the set of configuration parameters, the set of identifiers of files known not to be malware, and the set of identifiers of files known to be malware after sending the first file.

The nature of starbursts. ii. the duration of starbursts in dwarf galaxies

Abstract: The starburst phenomenon can shape the evolution of the host galaxy and the surrounding intergalactic medium. The extent of the evolutionary impact is partly determined by the duration of the starburst, which has a direct correlation with both the amount of stellar feedback and the development of galactic winds, particularly for smaller mass dwarf systems. We measure the duration of starbursts in twenty nearby, ongoing, and “fossil” starbursts in dwarf galaxies based on the recent star formation histories derived from resolved stellar population data obtained with the Hubble Space Telescope. Contrary to the shorter times of 3–10 Myr often cited, the starburst durations we measure range from 450 to 650 Myr in fifteen of the dwarf galaxies and up to 1.3 Gyr in four galaxies; these longer durations are comparable to or longer than the dynamical timescales for each system. The same feedback from massive stars that may quench the flickering star formation does not disrupt the overall burst event in our sample of galaxies. While five galaxies present fossil bursts, fifteen galaxies show ongoing bursts and thus the final durations may be longer than we report here for these systems. One galaxy shows a burst that has been ongoing for only 20 Myr; we are likely seeing the beginning of a burst event in this system. Using the duration of the starbursts, we calculate that the bursts deposited 10 53.9 –10 57.2 erg of energy into the interstellar medium through stellar winds and supernovae, and produced 3%−26% of the host galaxy’s mass.

Method and apparatus for tri-band feed with pseudo-monopulse tracking

Abstract: Methods and apparatus for a feed assembly for a reflector antenna including an aperture common to low, mid, and high frequency bands, a polyrod design to launch signals in the mid and high frequency bands, a horn to launch signals in the low frequency band, a co-located phase center for launching signals in the low, mid, and high frequency bands, and a low-band monopulse array located on a surface about the aperture to track a satellite.

THE ACS LCID PROJECT. III. THE STAR FORMATION HISTORY OF THE CETUS dSph GALAXY: A POST-REIONIZATION FOSSIL*

Abstract: We use deep HST/ACS observations to calculate the star formation history (SFH) of the Cetus dwarf spheroidal (dSph) galaxy. Our photometry reaches below the oldest main-sequence turnoffs, which allows us to estimate the age and duration of the main episode of star formation in Cetus. This is well approximated by a single episode that peaked roughly 12 ± 0.5 Gyr ago and lasted no longer than about 1.9 ± 0.5 Gyr (FWHM). Our solution also suggests that essentially no stars formed in Cetus during the past 8 Gyr. This makes Cetus' SFH comparable to that of the oldest Milky Way dSphs. Given the current isolation of Cetus in the outer fringes of the Local Group, the dominant old population implies that Cetus is a clear outlier in the morphology-Galactocentric distance relation that holds for the majority of the Milky Way dwarf satellites. Our results also show that Cetus continued forming stars until z 1, long after the universe was reionized, and that there is no clear signature of the epoch of reionization in Cetus' SFH. We briefly discuss the implications of these results for dwarf galaxy evolution models. Finally, we present a comprehensive account of the data reduction and analysis strategy adopted for all galaxies targeted by the LCID (Local Cosmology from Isolated Dwarfs) project. We employ two different photometry codes (DAOPHOT/ALLFRAME and DOLPHOT), three different SFH reconstruction codes (IAC-pop/MinnIAC, MATCH, and COLE), and two stellar evolution libraries (BaSTI and Padova/Girardi), allowing for a detailed assessment of the modeling and observational uncertainties.

Exact particle flow for nonlinear filters

Abstract: We have invented a new theory of exact particle flow for nonlinear filters. This generalizes our theory of particle flow that is already many orders of magnitude faster than standard particle filters and which is several orders of magnitude more accurate than the extended Kalman filter for difficult nonlinear problems. The new theory generalizes our recent log-homotopy particle flow filters in three ways: (1) the particle flow corresponds to the exact flow of the conditional probability density; (2) roughly speaking, the old theory was based on incompressible flow (like subsonic flight in air), whereas the new theory allows compressible flow (like supersonic flight in air); (3) the old theory suffers from obstruction of particle flow as well as singularities in the equations for flow, whereas the new theory has no obstructions and no singularities. Moreover, our basic filter theory is a radical departure from all other particle filters in three ways: (a) we do not use any proposal density; (b) we never resample; and (c) we compute Bayes' rule by particle flow rather than as a point wise multiplication.

The advanced camera for surveys nearby galaxy survey treasury. v. radial star formation history of ngc 300

Abstract: We present new Hubble Space Telescope (HST) observations of NGC 300 taken as part of the Advanced Camera for Surveys Nearby Galaxy Survey Treasury (ANGST). Individual stars are resolved in these images down to an absolute magnitude of M F814W = 1.0 (below the red clump). We determine the star formation history of the galaxy in six radial bins by comparing our observed color-magnitude diagrams (CMDs) with synthetic CMDs based on theoretical isochrones. We find that the stellar disk out to 5.4 kpc is primarily old, in contrast with the outwardly similar galaxy M33. We determine the scale length as a function of age and find evidence for inside-out growth of the stellar disk: the scale length has increased from 1.1 ± 0.1 kpc 10 Gyr ago to 1.3 ± 0.1 kpc at present, indicating a buildup in the fraction of young stars at larger radii. As the scale length of M33 has recently been shown to have increased much more dramatically with time, our results demonstrate that two galaxies with similar sizes and morphologies can have very different histories. With an N-body simulation of a galaxy designed to be similar to NGC 300, we determine that the effects of radial migration should be minimal. We trace the metallicity gradient as a function of time and find a present-day metallicity gradient consistent with that seen in previous studies. Consistent results are obtained from archival images covering the same radial extent but differing in placement and filter combination.

Assessing the impact of healthy work organization intervention

Abstract: This research evaluates a healthy work organization intervention implemented in a retail setting. Using a participatory process, employee teams in I I intervention stores developed customized plans for improving work organization at their sites. Ten comparable stores served as controls. Employee surveys were administered prior to the intervention and twice again at 12-month intervals. Business results were compiled monthly for each store. The baseline data were used by the teams to identify needs and establish action priorities for their stores. Most study outcomes declined across time for all stores, due primarily to internal corporate events and a generally adverse economic environment. However, the intervention process appeared to buffer some of these declines; intervention stores fared better in terms of selected aspects of organizational climate and psychological work adjustment. Intervention stores also performed better than controls on general indices of perceived health and safety and two of the four business outcomes: employee turnover and sales per labour hour. These results are discussed in terms of the challenges involved in evaluating organizational-level interventions in work settings.

The ACS LCID Project. VI. The Star Formation History of The Tucana dSph and The Relative Ages of the Isolated dSph Galaxies

Abstract: We present a detailed study of the star formation history (SFH) of the Tucana dwarf spheroidal galaxy. High-quality, deep HST/ACS data, collected in the framework of the LCID project, allowed us to obtain the deepest color-magnitude diagram to date, reaching the old main-sequence turnoff (F814 ~ 29) with good photometric accuracy. Our analysis, based on three different SFH codes, shows that Tucana is an old and metal-poor stellar system, which experienced a strong initial burst of star formation at a very early epoch (13 Gyr ago) which lasted a maximum of 1 Gyr (sigma value). We are not able to unambiguously answer the question of whether most star formation in Tucana occurred before or after the end of the reionization era, and we analyze alternative scenarios that may explain the transformation of Tucana from a gas-rich galaxy into a dSph. Current measurements of its radial velocity do not preclude that Tucana may have crossed the inner regions of the Local Group (LG) once, and so gas stripping by ram pressure and tides due to a close interaction cannot be ruled out. A single pericenter passage would generate insufficient tidal heating to turn an originally disky dwarf into a true dSph; however, this possibility would be consistent with the observed residual rotation in Tucana. On the other hand, the high star formation rate measured at early times may have injected enough energy into the interstellar medium to blow out a significant fraction of the initial gas content. Gas that is heated but not blown out would also be more easily stripped via ram pressure. We compare the SFH inferred for Tucana with that of Cetus, the other isolated LG dSph galaxy in the LCID sample. We show that the formation time of the bulk of star formation in Cetus is clearly delayed with respect to that of Tucana. This reinforces the conclusion of Monelli et al. that Cetus formed the vast majority of its stars after the end of the reionization era implying, therefore, that small dwarf galaxies are not necessarily strongly affected by reionization, in agreement with many state-of-the-art cosmological models.

Hepatitis C virus coinfection and the risk of cardiovascular disease among HIV‐infected patients

Abstract: Background Among HIV-infected patients, hepatitis C virus (HCV) coinfection is associated with lower cholesterol levels, but it remains unclear how it affects cardiovascular outcomes. Methods We performed logistic regression to evaluate acute myocardial infarction (AMI) and cerebrovascular disease (CVD) events by HCV status among HIV-infected US veterans in the highly active antiretroviral therapy (HAART) era (1996–2004). We then performed survival analyses to evaluate incident AMI and CVD, exploring antiretroviral therapy (ART) as a time-dependent variable. Results A total of 19 424 HIV-infected patients [31.6% of whom were HCV-coinfected (HIV/HCV)] contributed 76 376 patient-years of follow-up. HCV coinfection was associated with lower rates of hypercholesterolaemia (18.0% in HIV/HCV vs. 30.7% in HIV-only patients; P<0.001), but higher rates of hypertension (43.8%vs. 35.6%; P<0.0001), type 2 diabetes mellitus (16.2%vs. 11.1%; P<0.0001) and smoking (36.7%vs. 24.7%; P=0.009). Rates of AMI and CVD were significantly higher among HIV/HCV than HIV-only patients: 4.19 vs. 3.36 events/1000 patient-years, respectively (P<0.001), for AMI; and 12.47 vs. 11.12 events/1000 patient-years, respectively (P<0.001), for CVD. When analyses were controlled for diabetes mellitus, hypertension, age and duration of ART, hazard ratios (HRs) among those with HIV/HCV (vs. HIV only) were 1.25 [95% confidence interval (CI) 0.98–1.61; P=0.072] for AMI and 1.20 (CI 1.04–1.38; P=0.013) for CVD. Hypertension (HR 2.05; P<0.001), greater age (HR 1.79; P<0.001) and longer duration (cumulative years) of antiretroviral use (HR 1.12; P=0.0411) were also associated with increased risk of AMI in the adjusted model. Conclusions In the HAART era, HCV coinfection was associated with a significantly increased risk of CVD and a trend towards an increased risk of AMI among HIV-infected patients.

A mm-Wave Power-Harvesting RFID Tag in 90 nm CMOS

Abstract: A mm-wave power-harvesting RFID tag is implemented in 90 nm CMOS. Operation at mm-wave reduces antenna size and could allow antenna integration on-chip. This, together with power harvesting that can be used in lieu of a battery, can result in a pinless, CMOS-only tag with no package and no off-chip components whatsoever. The tag harvests energy from the incoming mm-wave continuous wave (CW) signal transmitted by the reader and then uses a 60 GHz free-running oscillator to transmit back pulse-width modulated bursts. An in-depth treatment of the voltage multiplier and associated matching network and implications on tag range are presented. With 2 dBm mm-wave input power, the tag achieves a rate of 5 kb/s. The RFIC size is 1.3 × 0.95 mm2 including pads.

Networked symbiotic edge user infrastructure

Abstract: A networked symbiotic assistive user system is presented. The architecture of the system allows devices worn by medical first responders such as medics or EMTs, to connect wirelessly to devices coupled to patients, devices worn by other medical first responders and adapter devices (such as those that may be located in air and/or land evacuation vehicles) that connect to a legacy infrastructure. Using a variety of medical first responder oriented communications protocols and applications, the devices can exchange information with all of the other devices in a manner that assists the medical first responders as well as personnel associated with the legacy infrastructure (e.g., tactical command operations personnel, first aid station personnel, or other medical facilities personnel).

Temporal tracking robot control system

Abstract: A temporal controller for mobile robot path planning includes a sensor module for receiving data corresponding to spatial locations of at least one object, and a temporal control module operatively coupled to the sensor module, the temporal control module configured to predict future locations of the at least one object based on data received by the sensor module. The controller further includes a temporal simulation module operatively coupled to the temporal control module, wherein the temporal simulation module configured to use the predicted future locations of the at least one object to simulate multiple robot motion hypothesis for object avoidance and trajectory planning.

Systems and methods for collision avoidance in unmanned aerial vehicles

Abstract: Systems and methods for collision avoidance in unmanned aerial vehicles are provided. In one embodiment, the invention relates to a method for collision avoidance system for an unmanned aerial vehicle (UAV), the method including scanning for objects within a preselected range of the UAV using a plurality of phased array radar sensors, receiving scan information from each of the plurality of phased array radar sensors, wherein the scan information includes information indicative of objects detected within the preselected range of the UAV, determining maneuver information including whether to change a flight path of the UAV based on the scan information, and sending the maneuver information to a flight control circuitry of the UAV.

Tracking People with a 360-Degree Lidar

Abstract: Advances in lidar technology, in particular 360-degreelidar sensors, create new opportunities to augment andimprove traditional surveillance systems. This paperdescribes an initial challenge to use a single stationary360-degree lidar sensor to detect and track people movingthroughout a scene in real-time. The depicted approachfocuses on overcoming three primary challenges inherentin any lidar tracker: classification and matching errorsbetween multiple human targets, segmentation errorsbetween humans and fixed objects in the scene, andsegmentation errors between targets that are very closetogether.

Hybrid metal fan blade

Abstract: A fan blade is disclosed comprising a lightweight metallic airfoil portion and a high-strength sheath portion. The airfoil portion has a forward airfoil edge, a first airfoil surface, and a second airfoil surface. The sheath portion has a sheath head section, a first sheath flank, and a second sheath flank, both flanks extending chordwise from the forward sheath section. The sheath portion is bonded to the airfoil portion such that the sheath head section covers the forward airfoil edge, defining a blade leading edge. The first sheath flank covers a portion of the first airfoil surface proximate the airfoil forward edge, jointly defining a blade suction surface. The second sheath flank covers a portion of the second airfoil surface proximate the airfoil forward edge, jointly defining a blade pressure surface.

Automated camera cleaning system

Abstract: Embodiments of an automated camera cleaning system are provided. In one embodiment, the automated camera cleaning system includes an optical path, an optically-transmissive lens shield through which the optical path extends, a housing in which the optically-transmissive lens shield is at least partially disposed, and a motor coupled to the lens shield. When energized, the motor moves the optically-transmissive lens shield relative to the housing to vary the region of the optically-transmissive lens shield positioned in the optical path.

Creative patterns and stimulation in conceptual design

Abstract: Conceptual design is a creative process. Designers create functions to satisfy customer needs and behaviors and forms to fulfill their functions. Although cognitive processes are at the center in developing new ideas, they are rarely taken into account in research and development of design support methods and systems. It is conceivable that if one understands how cognitive processes are stimulated to generate design ideas, then more effective methods and tools can be developed to support conceptual design. In this article, a cognitive model of conceptual design is developed to capture the relationships among design entities, design operations, and cognitive processes. A protocol analysis is performed to evaluate the model, and a cognitive experiment carried out to study the creative patterns and stimulating relationships. The results show that designers exhibit patterns of creative design behavior, and that these patterns can be captured and instilled into the design process to promote creativity.

Secure field-programmable gate array (fpga) architecture

Abstract: A method and system for configuring a field-programmable gate array (FPGA) includes receiving an encrypted FPGA load-decryption key at an FPGA from a remote key-storage device. The remote key-storage device may be external to and operatively connected with the FPGA. The encrypted FPGA load-decryption key is decrypted using a session key, which may be stored at both the FPGA and the remote key-storage device. Encrypted FPGA-configuration data is received at the FPGA, and decrypted and authenticated using the decrypted FPGA load-decryption key. The decryption of the FPGA-configuration data may indicate a cryptographic state associated with the FPGA-configuration data, which may be used in recurring authentication of the FPGA-configuration data. For recurring authentication, a challenge message may be received at the FPGA from an authentication device, which may be encrypted using the cryptographic state and the session key to generate a response message. The response message may then be sent to the authentication device to determine authenticity of the FPGA-configuration data.

The Application of Cloud Computing to Astronomy: A Study of Cost and Performance

Abstract: Cloud computing is a powerful new technology that is widely used in the business world. Recently, we have been investigating the benefits it offers to scientific computing. We have used three workflow applications to compare the performance of processing data on the Amazon EC2 cloud with the performance on the Abe high-performance cluster at the National Center for Supercomputing Applications (NCSA). We show that the Amazon EC2 cloud offers better performance and value for processor- and memory-limited applications than for I/O-bound applications. We provide an example of how the cloud is well suited to the generation of a science product: an atlas of period grams for the 210,000 light curves released by the NASA Kepler Mission. This atlas will support the identification of periodic signals, including those due to transiting exoplanets, in the Kepler data sets.

Drug-Eluting versus Bare-Metal Stent for Treatment of Saphenous Vein Grafts: A Meta-Analysis

Abstract: Background: Saphenous vein grafts develop an aggressive atherosclerotic process and the efficacy of drug eluting stents (DES) in treating saphenous vein graft (SVG) lesions has not been convincingly demonstrated. The aim of this study was to review and analyze the current literature for controlled studies comparing DES versus bare metal stents (BMS) for treatment of SVG stenoses. Methodology/Principal Findings: We searched several scientific databases and conference proceedings up to March 15, 2010 for controlled studies comparing target vessel revascularization (TVR) between DES and BMS. Summary odds ratios (OR) for the primary endpoint TVR and secondary endpoints infarction, stent thrombosis and death were calculated using random-effect models. A total of 29 studies (3 randomized controlled trials RCT) involving 7549 (202 in RCT) patients were included. The need for target vessel revascularization in the DES group tended to be lower compared to BMS for the 3 RCT (OR 0.50 [0.24–1.00]; p=0.051) and for observational studies (0.62 [0.49–0.79]; p,0.001). There was no significant difference in the risk for myocardial infarction in the RCT (OR 1.25 [0.22–6.99]; p=0.250) but a lower risk for DES based on the observational studies 0.68 [0.49–0.95]; p=0.023. The risk for stent thrombosis was found to be non-different in the RCT (OR 0.78 [0.03–21.73], p=0.885) while it was in favor of DES in the observational studies (0.58 [0.38 – 0.84]; p,0.001). The mortality was not significantly different between DES and BMS in the RCT’s (OR 2.22 [0.17 – 29.50]; p=0.546) while the observation studies showed a decreased mortality in the DES group (0.69 [0.55–0.85]; p,0.001). Conclusion: DES may decrease TVR rate in treatment of SVG stenoses. No differences in reinfarction rate, stent thrombosis or mortality was found between the DES and BMS groups in the RCT’s while the observational data showed lower risk for myocardial infarction, stent thrombosis and death in the DES group. This may be a result of patient selection bias in the observational studies or represent a true finding that was not the detected in the RCT analysis due to limited statistical power.

High Performance Mixed Signal and RF Circuits Enabled by the Direct Monolithic Heterogeneous Integration of GaN HEMTs and Si CMOS on a Silicon Substrate

Abstract: We present recent results on the direct heterogeneous integration of InP HBTs and Si CMOS on a silicon template wafer or SOLES (Silicon On Lattice Engineered Substrate). InP HBTs whose performance are comparable to HBTs on the native InP substrates have been repeatedly achieved. 100% heterogeneous interconnect yield has been achieved on daisy chain test structures with CMOS-InP HBT spacing (interconnect length) as small as 2.5um. In DARPA COSMOS Phase 1 we designed and fabricated a differential amplifier that met the program Go/NoGo metrics with first pass design success. As the COSMOS Phase 2 demonstration vehicle we designed and fabricated a low power dissipation, high resolution, 500MHz bandwidth digital-to-analog converter (DAC).

System and method for organizing, managing and running enterprise-wide scans

Abstract: Disclosed is a system and method for creating, organizing, and monitoring computer searches across a large number of networked computers. The system allows individual searches to be created and tailored depending upon specific objectives. Once established, the system permits the search parameters to be subsequently edited as needed. A graphical user interface (GUI) allows users to view established searches and to monitor searches once activated. Search results can also be tabulated by way of the GUI.