Uncoordinated MAC for Adaptive Multi Beam Directional Networks: Analysis and Evaluation

DTIC Science & Technology

2016-08-01

control (MAC) policies for emerging systems that are equipped with fully digital antenna arrays which are capable of adaptive multi-beam directional...Adaptive Beam- forming, Multibeam, Directional Networking, Random Access, Smart Antennas I. INTRODUCTION Fully digital beamforming antenna arrays that...are capable of adaptive multi-beam communications are quickly becoming a reality. These antenna arrays allow users to form multiple simultaneous

An experimental SMI adaptive antenna array simulator for weak interfering signals

NASA Technical Reports Server (NTRS)

Dilsavor, Ronald S.; Gupta, Inder J.

1991-01-01

An experimental sample matrix inversion (SMI) adaptive antenna array for suppressing weak interfering signals is described. The experimental adaptive array uses a modified SMI algorithm to increase the interference suppression. In the modified SMI algorithm, the sample covariance matrix is redefined to reduce the effect of thermal noise on the weights of an adaptive array. This is accomplished by subtracting a fraction of the smallest eigenvalue of the original covariance matrix from its diagonal entries. The test results obtained using the experimental system are compared with theoretical results. The two show a good agreement.

SMI adaptive antenna arrays for weak interfering signals. [Sample Matrix Inversion

NASA Technical Reports Server (NTRS)

Gupta, Inder J.

1986-01-01

The performance of adaptive antenna arrays in the presence of weak interfering signals (below thermal noise) is studied. It is shown that a conventional adaptive antenna array sample matrix inversion (SMI) algorithm is unable to suppress such interfering signals. To overcome this problem, the SMI algorithm is modified. In the modified algorithm, the covariance matrix is redefined such that the effect of thermal noise on the weights of adaptive arrays is reduced. Thus, the weights are dictated by relatively weak signals. It is shown that the modified algorithm provides the desired interference protection.

Adaptive array antenna for satellite cellular and direct broadcast communications

NASA Technical Reports Server (NTRS)

Horton, Charles R.; Abend, Kenneth

1993-01-01

Adaptive phased-array antennas provide cost-effective implementation of large, light weight apertures with high directivity and precise beamshape control. Adaptive self-calibration allows for relaxation of all mechanical tolerances across the aperture and electrical component tolerances, providing high performance with a low-cost, lightweight array, even in the presence of large physical distortions. Beam-shape is programmable and adaptable to changes in technical and operational requirements. Adaptive digital beam-forming eliminates uplink contention by allowing a single electronically steerable antenna to service a large number of receivers with beams which adaptively focus on one source while eliminating interference from others. A large, adaptively calibrated and fully programmable aperture can also provide precise beam shape control for power-efficient direct broadcast from space. Advanced adaptive digital beamforming technologies are described for: (1) electronic compensation of aperture distortion, (2) multiple receiver adaptive space-time processing, and (3) downlink beam-shape control. Cost considerations for space-based array applications are also discussed.

Optimizing Satellite Communications With Adaptive and Phased Array Antennas

NASA Technical Reports Server (NTRS)

Ingram, Mary Ann; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Popovic, Zoya; Langley, John; Barott, William C.; Ahmed, M. Usman; Mandl, Dan

2004-01-01

A new adaptive antenna array architecture for low-earth-orbiting satellite ground stations is being investigated. These ground stations are intended to have no moving parts and could potentially be operated in populated areas, where terrestrial interference is likely. The architecture includes multiple, moderately directive phased arrays. The phased arrays, each steered in the approximate direction of the satellite, are adaptively combined to enhance the Signal-to-Noise and Interference-Ratio (SNIR) of the desired satellite. The size of each phased array is to be traded-off with the number of phased arrays, to optimize cost, while meeting a bit-error-rate threshold. Also, two phased array architectures are being prototyped: a spacefed lens array and a reflect-array. If two co-channel satellites are in the field of view of the phased arrays, then multi-user detection techniques may enable simultaneous demodulation of the satellite signals, also known as Space Division Multiple Access (SDMA). We report on Phase I of the project, in which fixed directional elements are adaptively combined in a prototype to demodulate the S-band downlink of the EO-1 satellite, which is part of the New Millennium Program at NASA.

V-shaped resonators for addition of broad-area laser diode arrays

DOEpatents

Liu, Bo; Liu, Yun; Braiman, Yehuda Y.

2012-12-25

A system and method for addition of broad-area semiconductor laser diode arrays are described. The system can include an array of laser diodes, a V-shaped external cavity, and grating systems to provide feedback for phase-locking of the laser diode array. A V-shaped mirror used to couple the laser diode emissions along two optical paths can be a V-shaped prism mirror, a V-shaped stepped mirror or include multiple V-shaped micro-mirrors. The V-shaped external cavity can be a ring cavity. The system can include an external injection laser to further improve coherence and phase-locking.

Compensated individually addressable array technology for human breast imaging

DOEpatents

Lewis, D. Kent

2003-01-01

A method of forming broad bandwidth acoustic or microwave beams which encompass array design, array excitation, source signal preprocessing, and received signal postprocessing. This technique uses several different methods to achieve improvement over conventional array systems. These methods are: 1) individually addressable array elements; 2) digital-to-analog converters for the source signals; 3) inverse filtering from source precompensation; and 4) spectral extrapolation to expand the bandwidth of the received signals. The components of the system will be used as follows: 1) The individually addressable array allows scanning around and over an object, such as a human breast, without any moving parts. The elements of the array are broad bandwidth elements and efficient radiators, as well as detectors. 2) Digital-to-analog converters as the source signal generators allow virtually any radiated field to be created in the half-space in front of the array. 3) Preprocessing allows for corrections in the system, most notably in the response of the individual elements and in the ability to increase contrast and resolution of signal propagating through the medium under investigation. 4) Postprocessing allows the received broad bandwidth signals to be expanded in a process similar to analytic continuation. Used together, the system allows for compensation to create beams of any desired shape, control the wave fields generated to correct for medium differences, and improve contract and resolution in and through the medium.

The Effect of a Pulsed Interference Signal on an Adaptive Array.

DTIC Science & Technology

1981-04-01

eigenvectors exist.) Using a spectral decomp- osition formula [10,11], we may write e-kM in the form -kM -k(T- )-kpo 3 -kg i (e -k = e a : .iZ e eie i , (28...N 0 (No/T b) In addition, for this analysis we shall assume the interference power at the array output has the same effect on detector performance... Sensitive Adaptive Array," to appear in IEEE Trans. Antennas and Propagation. 7. R.T. Compton, Jr., "The Tripole Antenna - An Adaptive Array with Full

A FPGA-based Fast Converging Digital Adaptive Filter for Real-time RFI Mitigation on Ground Based Radio Telescopes

NASA Astrophysics Data System (ADS)

Finger, R.; Curotto, F.; Fuentes, R.; Duan, R.; Bronfman, L.; Li, D.

2018-02-01

Radio Frequency Interference (RFI) is a growing concern in the radio astronomy community. Single-dish telescopes are particularly susceptible to RFI. Several methods have been developed to cope with RF-polluted environments, based on flagging, excision, and real-time blanking, among others. All these methods produce some degree of data loss or require assumptions to be made on the astronomical signal. We report the development of a real-time, digital adaptive filter implemented on a Field Programmable Gate Array (FPGA) capable of processing 4096 spectral channels in a 1 GHz of instantaneous bandwidth. The filter is able to cancel a broad range of interference signals and quickly adapt to changes on the RFI source, minimizing the data loss without any assumption on the astronomical or interfering signal properties. The speed of convergence (for a decrease to a 1%) was measured to be 208.1 μs for a broadband noise-like RFI signal and 125.5 μs for a multiple-carrier RFI signal recorded at the FAST radio telescope.

A Phase Correction Technique Based on Spatial Movements of Antennas in Real-Time (S.M.A.R.T.) for Designing Self-Adapting Conformal Array Antennas

NASA Astrophysics Data System (ADS)

Roy, Sayan

This research presents a real-time adaptive phase correction technique for flexible phased array antennas on conformal surfaces of variable shapes. Previously reported pattern correctional methods for flexible phased array antennas require prior knowledge on the possible non-planar shapes in which the array may adapt for conformal applications. For the first time, this initial requirement of shape curvature knowledge is no longer needed and the instantaneous information on the relative location of array elements is used here for developing a geometrical model based on a set of Bezier curves. Specifically, by using an array of inclinometer sensors and an adaptive phase-correctional algorithm, it has been shown that the proposed geometrical model can successfully predict different conformal orientations of a 1-by-4 antenna array in real-time without the requirement of knowing the shape-changing characteristics of the surface the array is attached upon. Moreover, the phase correction technique is validated by determining the field patterns and broadside gain of the 1-by-4 antenna array on four different conformal surfaces with multiple points of curvatures. Throughout this work, measurements are shown to agree with the analytical solutions and full-wave simulations.

Effects of additional interfering signals on adaptive array performance

NASA Technical Reports Server (NTRS)

Moses, Randolph L.

1989-01-01

The effects of additional interference signals on the performance of a fully adaptive array are considered. The case where the number of interference signals exceeds the number of array degrees of freedom is addressed. It is shown how performance is affected as a function of the number of array elements, the number of interference signals, and the directivity of the array antennas. By using directive auxiliary elements, the performance of the array can be as good as the performance when the additional interference signals are not present.

Power Inversion in a Tapped Delay-Line Array.

DTIC Science & Technology

1975-03-01

and identify by block number) This report discusses recent studies on adaptive arrays for theNavy ITACS system. The report considers the power inversion...this report we discuss recent studies on adaptive arrays for the Navy ITACS system. The goal of this research is to develop an adaptive antenna system...here is a continuation of earlier research on power inversion by Compton, Lee, and Schwegman [1,2,3,4]. This work differs from previous studies in that

Large-N correlator systems for low frequency radio astronomy

NASA Astrophysics Data System (ADS)

Foster, Griffin

Low frequency radio astronomy has entered a second golden age driven by the development of a new class of large-N interferometric arrays. The low frequency array (LOFAR) and a number of redshifted HI Epoch of Reionization (EoR) arrays are currently undergoing commission and regularly observing. Future arrays of unprecedented sensitivity and resolutions at low frequencies, such as the square kilometer array (SKA) and the hydrogen epoch of reionization array (HERA), are in development. The combination of advancements in specialized field programmable gate array (FPGA) hardware for signal processing, computing and graphics processing unit (GPU) resources, and new imaging and calibration algorithms has opened up the oft underused radio band below 300 MHz. These interferometric arrays require efficient implementation of digital signal processing (DSP) hardware to compute the baseline correlations. FPGA technology provides an optimal platform to develop new correlators. The significant growth in data rates from these systems requires automated software to reduce the correlations in real time before storing the data products to disk. Low frequency, widefield observations introduce a number of unique calibration and imaging challenges. The efficient implementation of FX correlators using FPGA hardware is presented. Two correlators have been developed, one for the 32 element BEST-2 array at Medicina Observatory and the other for the 96 element LOFAR station at Chilbolton Observatory. In addition, calibration and imaging software has been developed for each system which makes use of the radio interferometry measurement equation (RIME) to derive calibrations. A process for generating sky maps from widefield LOFAR station observations is presented. Shapelets, a method of modelling extended structures such as resolved sources and beam patterns has been adapted for radio astronomy use to further improve system calibration. Scaling of computing technology allows for the development of larger correlator systems, which in turn allows for improvements in sensitivity and resolution. This requires new calibration techniques which account for a broad range of systematic effects.

Multi-gas sensing with quantum cascade laser array in the mid-infrared region

NASA Astrophysics Data System (ADS)

Bizet, Laurent; Vallon, Raphael; Parvitte, Bertrand; Brun, Mickael; Maisons, Gregory; Carras, Mathieu; Zeninari, Virginie

2017-05-01

Wide tunable lasers sources are useful for spectroscopy of complex molecules that have broad absorption spectra and for multiple sensing of smaller molecules. A region of interest is the mid-infrared region, where many species have strong ro-vibrational modes. In this paper a novel broad tunable source composed of a QCL DFB array and an arrayed waveguide grating (also called multiplexer) was used to perform multi-species spectroscopy (CO, C2H2, CO2). The array and the multiplexer are associated in a way to obtain a prototype that is non-sensitive to mechanical vibrations. A 2190-2220 cm^{-1} spectral range is covered by the chip. The arrayed waveguide grating combines beams to have a single output. A multi-pass White cell was used to demonstrate the efficiency of the multiplexer.

Automated, Miniaturized Instrument for Measuring Gene Expression in Space

NASA Technical Reports Server (NTRS)

Pohorille, A.; Peyvan, K.; Danley, D.; Ricco, A. J.

2010-01-01

To facilitate astrobiological studies on the survival and adaptation of microorganisms and mixed microbial cultures to space environment, we have been developing a fully automated, miniaturized system for measuring their gene expression on small spacecraft. This low-cost, multi-purpose instrument represents a major scientific and technological advancement in our ability to study the impact of the space environment on biological systems by providing data on cellular metabolism and regulation orders of magnitude richer than what is currently available. The system supports growth of the organism, lyse it to release the expressed RNA, label the RNA, read the expression levels of a large number of genes by microarray analysis of labeled RNA and transmit the measurements to Earth. To measure gene expression we use microarray technology developed by CombiMatrix, which is based on electrochemical reactions on arrays of electrodes on a semiconductor substrate. Since the electrical integrity of the microarray remains intact after probe synthesis, the circuitry can be employed to sense nucleic acid binding at each electrode. CombiMatrix arrays can be sectored to allow multiple samples per chip. In addition, a single array can be used for several assays. The array has been integrated into an automated microfluidic cartridge that uses flexible reagent blisters and pinch pumping to move liquid reagents between chambers. The proposed instrument will help to understand adaptation of terrestrial life to conditions beyond the planet of origin, identify deleterious effects of the space environment, develop effective countermeasures against these effects, and test our ability to sustain and grow in space organisms that can be used for life support and in situ resource utilization during long-duration space exploration. The instrument is suitable for small satellite platforms, which provide frequent, low cost access to space. It can be also used on any other platform in space, including the ISS. It can be replicated and used with only small modifications in multiple biological experiments with a broad range of goals in mind.

Automated, Miniaturized Instrument for Measuring Gene Expression in Space

NASA Astrophysics Data System (ADS)

Pohorille, Andrew; Danley, David; Payvan, Kia; Ricco, Antonio

To facilitate astrobiological studies on the survival and adaptation of microorganisms and mixed microbial cultures to space environment, we have been developing a fully automated, minia-turized system for measuring their gene expression on small spacecraft. This low-cost, multi-purpose instrument represents a major scientific and technological advancement in our ability to study the impact of the space environment on biological systems by providing data on cel-lular metabolism and regulation orders of magnitude richer than what is currently available. The system supports growth of the organism, lyse it to release the expressed RNA, label the RNA, read the expression levels of a large number of genes by microarray analysis of labeled RNA and transmit the measurements to Earth. To measure gene expression we use microarray technology developed by CombiMatrix, which is based on electrochemical reactions on arrays of electrodes on a semiconductor substrate. Since the electrical integrity of the microarray re-mains intact after probe synthesis, the circuitry can be employed to sense nucleic acid binding at each electrode. CombiMatrix arrays can be sectored to allow multiple samples per chip. In addition, a single array can be used for several assays. The array has been integrated into an automated microfluidic cartridge that uses flexible reagent blisters and pinch pumping to move liquid reagents between chambers. The proposed instrument will help to understand adaptation of terrestrial life to conditions be-yond the planet of origin, identify deleterious effects of the space environment, develop effective countermeasures against these effects, and test our ability to sustain and grow in space organ-isms that can be used for life support and in situ resource utilization during long-duration space exploration. The instrument is suitable for small satellite platforms, which provide frequent, low cost access to space. It can be also used on any other platform in space, including the ISS. It can be replicated and used with only small modifications in multiple biological experiments with a broad range of goals in mind.

Optimization of multiple turbine arrays in a channel with tidally reversing flow by numerical modelling with adaptive mesh.

PubMed

Divett, T; Vennell, R; Stevens, C

2013-02-28

At tidal energy sites, large arrays of hundreds of turbines will be required to generate economically significant amounts of energy. Owing to wake effects within the array, the placement of turbines within will be vital to capturing the maximum energy from the resource. This study presents preliminary results using Gerris, an adaptive mesh flow solver, to investigate the flow through four different arrays of 15 turbines each. The goal is to optimize the position of turbines within an array in an idealized channel. The turbines are represented as areas of increased bottom friction in an adaptive mesh model so that the flow and power capture in tidally reversing flow through large arrays can be studied. The effect of oscillating tides is studied, with interesting dynamics generated as the tidal current reverses direction, forcing turbulent flow through the array. The energy removed from the flow by each of the four arrays is compared over a tidal cycle. A staggered array is found to extract 54 per cent more energy than a non-staggered array. Furthermore, an array positioned to one side of the channel is found to remove a similar amount of energy compared with an array in the centre of the channel.

FACT, Mega-ROSA, SOLAROSA

NASA Technical Reports Server (NTRS)

Spence, Brian; White, Steve; Schmid, Kevin; Douglas Mark

2012-01-01

The Flexible Array Concentrator Technology (FACT) is a lightweight, high-performance reflective concentrator blanket assembly that can be used on flexible solar array blankets. The FACT concentrator replaces every other row of solar cells on a solar array blanket, significantly reducing the cost of the array. The modular design is highly scalable for the array system designer, and exhibits compact stowage, good off-pointing acceptance, and mass/cost savings. The assembly s relatively low concentration ratio, accompanied by a large radiative area, provides for a low cell operating temperature, and eliminates many of the thermal problems inherent in high-concentration-ratio designs. Unlike other reflector technologies, the FACT concentrator modules function on both z-fold and rolled flexible solar array blankets, as well as rigid array systems. Mega-ROSA (Mega Roll-Out Solar Array) is a new, highly modularized and extremely scalable version of ROSA that provides immense power level range capability from 100 kW to several MW in size. Mega-ROSA will enable extremely high-power spacecraft and SEP-powered missions, including space-tug and largescale planetary science and lunar/asteroid exploration missions. Mega-ROSA's inherent broad power scalability is achieved while retaining ROSA s solar array performance metrics and missionenabling features for lightweight, compact stowage volume and affordability. This innovation will enable future ultra-high-power missions through lowcost (25 to 50% cost savings, depending on PV and blanket technology), lightweight, high specific power (greater than 200 to 400 Watts per kilogram BOL (beginning-of-life) at the wing level depending on PV and blanket technology), compact stowage volume (greater than 50 kilowatts per cubic meter for very large arrays), high reliability, platform simplicity (low failure modes), high deployed strength/stiffness when scaled to huge sizes, and high-voltage operation capability. Mega-ROSA is adaptable to all photovoltaic and concentrator flexible blanket technologies, and can readily accommodate standard multijunction and emerging ultra-lightweight IMM (inverted metamorphic) photovoltaic flexible blanket assemblies, as well as ENTECHs Stretched Lens Array (SLA) and DSSs (Deployable Space Systems) FACT, which allows for cost reduction at the array level.

Genome analysis of Daldinia eschscholtzii strains UM 1400 and UM 1020, wood-decaying fungi isolated from human hosts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Chai Ling; Yew, Su Mei; Ngeow, Yun Fong

Background: Daldinia eschscholtzii is a wood-inhabiting fungus that causes wood decay under certain conditions. It has a broad host range and produces a large repertoire of potentially bioactive compounds. However, there is no extensive genome analysis on this fungal species. Results: Two fungal isolates (UM 1400 and UM 1020) from human specimens were identified as Daldinia eschscholtzii by morphological features and ITS-based phylogenetic analysis. Both genomes were similar in size with 10,822 predicted genes in UM 1400 (35.8 Mb) and 11,120 predicted genes in UM 1020 (35.5 Mb). A total of 751 gene families were shared among both UM isolates,more » including gene families associated with fungus-host interactions. In the CAZyme comparative analysis, both genomes were found to contain arrays of CAZyme related to plant cell wall degradation. Genes encoding secreted peptidases were found in the genomes, which encode for the peptidases involved in the degradation of structural proteins in plant cell wall. In addition, arrays of secondary metabolite backbone genes were identified in both genomes, indicating of their potential to produce bioactive secondary metabolites. Both genomes also contained an abundance of gene encoding signaling components, with three proposed MAPK cascades involved in cell wall integrity, osmoregulation, and mating/filamentation. Besides genomic evidence for degrading capability, both isolates also harbored an array of genes encoding stress response proteins that are potentially significant for adaptation to living in the hostile environments. In conclusion: Our genomic studies provide further information for the biological understanding of the D. eschscholtzii and suggest that these wood-decaying fungi are also equipped for adaptation to adverse environments in the human host.« less

Genome analysis of Daldinia eschscholtzii strains UM 1400 and UM 1020, wood-decaying fungi isolated from human hosts

DOE PAGES

Chan, Chai Ling; Yew, Su Mei; Ngeow, Yun Fong; ...

2015-11-18

Background: Daldinia eschscholtzii is a wood-inhabiting fungus that causes wood decay under certain conditions. It has a broad host range and produces a large repertoire of potentially bioactive compounds. However, there is no extensive genome analysis on this fungal species. Results: Two fungal isolates (UM 1400 and UM 1020) from human specimens were identified as Daldinia eschscholtzii by morphological features and ITS-based phylogenetic analysis. Both genomes were similar in size with 10,822 predicted genes in UM 1400 (35.8 Mb) and 11,120 predicted genes in UM 1020 (35.5 Mb). A total of 751 gene families were shared among both UM isolates,more » including gene families associated with fungus-host interactions. In the CAZyme comparative analysis, both genomes were found to contain arrays of CAZyme related to plant cell wall degradation. Genes encoding secreted peptidases were found in the genomes, which encode for the peptidases involved in the degradation of structural proteins in plant cell wall. In addition, arrays of secondary metabolite backbone genes were identified in both genomes, indicating of their potential to produce bioactive secondary metabolites. Both genomes also contained an abundance of gene encoding signaling components, with three proposed MAPK cascades involved in cell wall integrity, osmoregulation, and mating/filamentation. Besides genomic evidence for degrading capability, both isolates also harbored an array of genes encoding stress response proteins that are potentially significant for adaptation to living in the hostile environments. In conclusion: Our genomic studies provide further information for the biological understanding of the D. eschscholtzii and suggest that these wood-decaying fungi are also equipped for adaptation to adverse environments in the human host.« less

Phylogenomic evolutionary surveys of subtilase superfamily genes in fungi.

PubMed

Li, Juan; Gu, Fei; Wu, Runian; Yang, JinKui; Zhang, Ke-Qin

2017-03-30

Subtilases belong to a superfamily of serine proteases which are ubiquitous in fungi and are suspected to have developed distinct functional properties to help fungi adapt to different ecological niches. In this study, we conducted a large-scale phylogenomic survey of subtilase protease genes in 83 whole genome sequenced fungal species in order to identify the evolutionary patterns and subsequent functional divergences of different subtilase families among the main lineages of the fungal kingdom. Our comparative genomic analyses of the subtilase superfamily indicated that extensive gene duplications, losses and functional diversifications have occurred in fungi, and that the four families of subtilase enzymes in fungi, including proteinase K-like, Pyrolisin, kexin and S53, have distinct evolutionary histories which may have facilitated the adaptation of fungi to a broad array of life strategies. Our study provides new insights into the evolution of the subtilase superfamily in fungi and expands our understanding of the evolution of fungi with different lifestyles.

Mutual coupling, channel model, and BER for curvilinear antenna arrays

NASA Astrophysics Data System (ADS)

Huang, Zhiyong

This dissertation introduces a wireless communications system with an adaptive beam-former and investigates its performance with different antenna arrays. Mutual coupling, real antenna elements and channel models are included to examine the system performance. In a beamforming system, mutual coupling (MC) among the elements can significantly degrade the system performance. However, MC effects can be compensated if an accurate model of mutual coupling is available. A mutual coupling matrix model is utilized to compensate mutual coupling in the beamforming of a uniform circular array (UCA). Its performance is compared with other models in uplink and downlink beamforming scenarios. In addition, the predictions are compared with measurements and verified with results from full-wave simulations. In order to accurately investigate the minimum mean-square-error (MSE) of an adaptive array in MC, two different noise models, the environmental and the receiver noise, are modeled. The minimum MSEs with and without data domain MC compensation are analytically compared. The influence of mutual coupling on the convergence is also examined. In addition, the weight compensation method is proposed to attain the desired array pattern. Adaptive arrays with different geometries are implemented with the minimum MSE algorithm in the wireless communications system to combat interference at the same frequency. The bit-error-rate (BER) of systems with UCA, uniform rectangular array (URA) and UCA with center element are investigated in additive white Gaussian noise plus well-separated signals or random direction signals scenarios. The output SINR of an adaptive array with multiple interferers is analytically examined. The influence of the adaptive algorithm convergence on the BER is investigated. The UCA is then investigated in a narrowband Rician fading channel. The channel model is built and the space correlations are examined. The influence of the number of signal paths, number of the interferers, Doppler spread and convergence are investigated. The tracking mode is introduced to the adaptive array system, and it further improves the BER. The benefit of using faster data rate (wider bandwidth) is discussed. In order to have better performance in a 3D space, the geometries of uniform spherical array (USAs) are presented and different configurations of USAs are discussed. The LMS algorithm based on temporal a priori information is applied to UCAs and USAs to beamform the patterns. Their performances are compared based on simulation results. Based on the analytical and simulation results, it can be concluded that mutual coupling slightly influences the performance of the adaptive array in communication systems. In addition, arrays with curvilinear geometries perform well in AWGN and fading channels.

Apparatus and method for imaging metallic objects using an array of giant magnetoresistive sensors

DOEpatents

Chaiken, Alison

2000-01-01

A portable, low-power, metallic object detector and method for providing an image of a detected metallic object. In one embodiment, the present portable low-power metallic object detector an array of giant magnetoresistive (GMR) sensors. The array of GMR sensors is adapted for detecting the presence of and compiling image data of a metallic object. In the embodiment, the array of GMR sensors is arranged in a checkerboard configuration such that axes of sensitivity of alternate GMR sensors are orthogonally oriented. An electronics portion is coupled to the array of GMR sensors. The electronics portion is adapted to receive and process the image data of the metallic object compiled by the array of GMR sensors. The embodiment also includes a display unit which is coupled to the electronics portion. The display unit is adapted to display a graphical representation of the metallic object detected by the array of GMR sensors. In so doing, a graphical representation of the detected metallic object is provided.

Implementation of LSCMA adaptive array terminal for mobile satellite communications

NASA Astrophysics Data System (ADS)

Zhou, Shun; Wang, Huali; Xu, Zhijun

2007-11-01

This paper considers the application of adaptive array antenna based on the least squares constant modulus algorithm (LSCMA) for interference rejection in mobile SATCOM terminals. A two-element adaptive array scheme is implemented with a combination of ADI TS201S DSP chips and Altera Stratix II FPGA device, which makes a cooperating computation for adaptive beamforming. Its interference suppressing performance is verified via Matlab simulations. Digital hardware system is implemented to execute the operations of LSCMA beamforming algorithm that is represented by an algorithm flowchart. The result of simulations and test indicate that this scheme can improve the anti-jamming performance of terminals.

Evaluation of microfabricated deformable mirror systems

NASA Astrophysics Data System (ADS)

Cowan, William D.; Lee, Max K.; Bright, Victor M.; Welsh, Byron M.

1998-09-01

This paper presents recent result for aberration correction and beam steering experiments using polysilicon surface micromachined piston micromirror arrays. Microfabricated deformable mirrors offer a substantial cost reduction for adaptive optic systems. In addition to the reduced mirror cost, microfabricated mirrors typically require low control voltages, thus eliminating high voltage amplifiers. The greatly reduced cost per channel of adaptive optic systems employing microfabricated deformable mirrors promise high order aberration correction at low cost. Arrays of piston micromirrors with 128 active elements were tested. Mirror elements are on a 203 micrometers 12 by 12 square grid. The overall array size is 2.4 mm square. The arrays were fabricated in the commercially available DARPA supported MUMPs surface micromachining foundry process. The cost per mirror array in this prototyping process is less than 200 dollars. Experimental results are presented for a hybrid correcting element comprised of a lenslet array and piston micromirror array, and for a piston micromirror array only. Also presented is a novel digital deflection micromirror which requires no digital to analog converters, further reducing the cost of adaptive optics system.

Quantum Dot and Polymer Composite Cross-Reactive Array for Chemical Vapor Detection.

PubMed

Bright, Collin J; Nallon, Eric C; Polcha, Michael P; Schnee, Vincent P

2015-12-15

A cross-reactive chemical sensing array was made from CdSe Quantum Dots (QDs) and five different organic polymers by inkjet printing to create segmented fluorescent composite regions on quartz substrates. The sensor array was challenged with exposures from two sets of analytes, including one set of 14 different functionalized benzenes and one set of 14 compounds related to security concerns, including the explosives trinitrotoluene (TNT) and ammonium nitrate. The array was broadly responsive to analytes with different chemical functionalities due to the multiple sensing mechanisms that altered the QDs' fluorescence. The sensor array displayed excellent discrimination between members within both sets. Classification accuracy of more than 93% was achieved, including the complete discrimination of very similar dinitrobenzene isomers and three halogenated, substituted benzene compounds. The simple fabrication, broad responsivity, and high discrimination capacity of this type of cross-reactive array are ideal qualities for the development of sensors with excellent sensitivity to chemical and explosive threats while maintaining low false alarm rates.

Sexual Dimorphism and the Origins of Human Spinal Health.

PubMed

Gilsanz, Vicente; Wren, Tishya A L; Ponrartana, Skorn; Mora, Stefano; Rosen, Clifford J

2018-04-01

Recent observations indicate that the cross-sectional area (CSA) of vertebral bodies is on average 10% smaller in healthy newborn girls than in newborn boys, a striking difference that increases during infancy and puberty and is greatest by the time of sexual and skeletal maturity. The smaller CSA of female vertebrae is associated with greater spinal flexibility and could represent the human adaptation to fetal load in bipedal posture. Unfortunately, it also imparts a mechanical disadvantage that increases stress within the vertebrae for all physical activities. This review summarizes the potential endocrine, genetic, and environmental determinants of vertebral cross-sectional growth and current knowledge of the association between the small female vertebrae and greater risk for a broad array of spinal conditions across the lifespan.

Application of Adaptive Beamforming to Signal Observations at the Mt. Meron Array, Israel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, D. B.

2010-06-07

The Mt. Meron array consists of 16 stations spanning an aperture of 3-4 kilometers in northern Israel. The array is situated in a region of substantial topographic relief, and is surrounded by settlements at close range (Figure 1). Consequently the level of noise at the array is high, which requires efforts at mitigation if distant regional events of moderate magnitude are to be observed. This note describes an initial application of two classic adaptive beamforming algorithms to data from the array to observe P waves from 5 events east of the array ranging in distance from 1100- 2150 kilometers.

Weight Vector Fluctuations in Adaptive Antenna Arrays Tuned Using the Least-Mean-Square Error Algorithm with Quadratic Constraint

NASA Astrophysics Data System (ADS)

Zimina, S. V.

2015-06-01

We present the results of statistical analysis of an adaptive antenna array tuned using the least-mean-square error algorithm with quadratic constraint on the useful-signal amplification with allowance for the weight-coefficient fluctuations. Using the perturbation theory, the expressions for the correlation function and power of the output signal of the adaptive antenna array, as well as the formula for the weight-vector covariance matrix are obtained in the first approximation. The fluctuations are shown to lead to the signal distortions at the antenna-array output. The weight-coefficient fluctuations result in the appearance of additional terms in the statistical characteristics of the antenna array. It is also shown that the weight-vector fluctuations are isotropic, i.e., identical in all directions of the weight-coefficient space.

Coherent Optical Adaptive Techniques (COAT)

DTIC Science & Technology

1975-01-01

8217 neceeemry and Identity by block number) Laser Phased Array Adaptive Optics Atmospheric-Turbulence and Thermal Blooming Compensation 20...characteristics of an experimental, visible wavelength, eighteen-element, self-adaptive optical phased array. Measurements on a well-characterized...V LOCAL PHASING ■ LOOP OPTICAL DETECTOR’ LOCAL LOCK / ROOF TOP "^/PROPAGATION’ ^ GLINT ■lm FOCAL LENGTH LENS DETECTOR DMWI rh

Broad-spectrum inhibition of Phytophthora infestans by fungal endophytes

PubMed Central

von Dahlen, Janina K; Schnake, Anika; Ginschel, Sarah; Schulz, Barbara; Rose, Laura E

2018-01-01

ABSTRACT Phytophthora infestans is a devastating pathogen of tomato and potato. It readily overcomes resistance genes and applied agrochemicals and hence even today causes large yield losses. Fungal endophytes provide a largely unexplored avenue of control of Phy. infestans. Not only do endophytes produce a wide array of bioactive metabolites, they may also directly compete with and defeat pathogens in planta. Here, we tested 12 fungal endophytes isolated from different plant species in vitro for their production of metabolites with anti- Phytophthora activity. Four well-performing isolates were evaluated for their ability to suppress nine isolates of Phy. infestans on agar medium and in planta. Two endophytes reliably inhibited all Phy. infestans isolates on agar medium, of which Phoma eupatorii isolate 8082 was the most promising. It nearly abolished infection by Phy. infestans in planta. Our data indicate a role for the production of anti-Phytophthora compounds by the fungus and/or an enhanced plant defense response, as evident by an enhanced anthocyanin production. Here, we present a potential biocontrol agent, which can inhibit a broad-spectrum of Phy. infestans isolates. Such broadly acting inhibition is ideal, because it allows for effective control of genetically diverse isolates and may slow the adaptation of Phy. infestans. PMID:29528408

Adaptive arrays for satellite communications

NASA Technical Reports Server (NTRS)

Gupta, I. J.; Ksienski, A. A.

1984-01-01

The suppression of interfering signals in a satellite communication system was studied. Adaptive arrays are used to suppress interference at the reception site. It is required that the interference be suppressed to very low levels and a modified adaptive circuit is used which accomplishes the desired objective. Techniques for the modification of the transmit patterns to minimize interference with neighboring communication links are explored.

Control, Filtering and Prediction for Phased Arrays in Directed Energy Systems

DTIC Science & Technology

2016-04-30

adaptive optics. 15. SUBJECT TERMS control, filtering, prediction, system identification, adaptive optics, laser beam pointing, target tracking, phase... laser beam control; furthermore, wavefront sensors are plagued by the difficulty of maintaining the required alignment and focusing in dynamic mission...developed new methods for filtering, prediction and system identification in adaptive optics for high energy laser systems including phased arrays. The

Electronic warfare antenna systems - Past and present

NASA Astrophysics Data System (ADS)

Yaw, D.

1981-09-01

In discussing fixed beam arrays, it is noted that an array may be used to create simultaneous fixed beams or to form asymmetric beams of a desired shape. Attention is also given to arrays and beam control, noting that for some electronic warfare applications combinations of broad and narrow beam antenna response are needed. Other topics include ECM jamming antenna techniques and advanced array systems.

LEO Download Capacity Analysis for a Network of Adaptive Array Ground Stations

NASA Technical Reports Server (NTRS)

Ingram, Mary Ann; Barott, William C.; Popovic, Zoya; Rondineau, Sebastien; Langley, John; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Steffes, Paul; Mandl, Dan

2005-01-01

To lower costs and reduce latency, a network of adaptive array ground stations, distributed across the United States, is considered for the downlink of a polar-orbiting low earth orbiting (LEO) satellite. Assuming the X-band 105 Mbps transmitter of NASA s Earth Observing 1 (EO-1) satellite with a simple line-of-sight propagation model, the average daily download capacity in bits for a network of adaptive array ground stations is compared to that of a single 11 m dish in Poker Flats, Alaska. Each adaptive array ground station is assumed to have multiple steerable antennas, either mechanically steered dishes or phased arrays that are mechanically steered in azimuth and electronically steered in elevation. Phased array technologies that are being developed for this application are the space-fed lens (SFL) and the reflectarray. Optimization of the different boresight directions of the phased arrays within a ground station is shown to significantly increase capacity; for example, this optimization quadruples the capacity for a ground station with eight SFLs. Several networks comprising only two to three ground stations are shown to meet or exceed the capacity of the big dish, Cutting the data rate by half, which saves modem costs and increases the coverage area of each ground station, is shown to increase the average daily capacity of the network for some configurations.

Three-dimensionally preserved integument reveals hydrodynamic adaptations in the extinct marine lizard Ectenosaurus (Reptilia, Mosasauridae).

PubMed

Lindgren, Johan; Everhart, Michael J; Caldwell, Michael W

2011-01-01

The physical properties of water and the environment it presents to its inhabitants provide stringent constraints and selection pressures affecting aquatic adaptation and evolution. Mosasaurs (a group of secondarily aquatic reptiles that occupied a broad array of predatory niches in the Cretaceous marine ecosystems about 98-65 million years ago) have traditionally been considered as anguilliform locomotors capable only of generating short bursts of speed during brief ambush pursuits. Here we report on an exceptionally preserved, long-snouted mosasaur (Ectenosaurus clidastoides) from the Santonian (Upper Cretaceous) part of the Smoky Hill Chalk Member of the Niobrara Formation in western Kansas, USA, that contains phosphatized remains of the integument displaying both depth and structure. The small, ovoid neck and/or anterior trunk scales exhibit a longitudinal central keel, and are obliquely arrayed into an alternating pattern where neighboring scales overlap one another. Supportive sculpturing in the form of two parallel, longitudinal ridges on the inner scale surface and a complex system of multiple, superimposed layers of straight, cross-woven helical fiber bundles in the underlying dermis, may have served to minimize surface deformation and frictional drag during locomotion. Additional parallel fiber bundles oriented at acute angles to the long axis of the animal presumably provided stiffness in the lateral plane. These features suggest that the anterior torso of Ectenosaurus was held somewhat rigid during swimming, thereby limiting propulsive movements to the posterior body and tail.

Experiment on a three-beam adaptive array for EHF frequency-hopped signals using a fast algorithm, phase-D

NASA Astrophysics Data System (ADS)

Yen, J. L.; Kremer, P.; Amin, N.; Fung, J.

1989-05-01

The Department of National Defence (Canada) has been conducting studies into multi-beam adaptive arrays for extremely high frequency (EHF) frequency hopped signals. A three-beam 43 GHz adaptive antenna and a beam control processor is under development. An interactive software package for the operation of the array, capable of applying different control algorithms is being written. A maximum signal to jammer plus noise ratio (SJNR) was found to provide superior performance in preventing degradation of user signals in the presence of nearby jammers. A new fast algorithm using a modified conjugate gradient approach was found to be a very efficient way to implement anti-jamming arrays based on maximum SJNR criterion. The present study was intended to refine and simplify this algorithm and to implement the algorithm on an experimental array for real-time evaluation of anti-jamming performance. A three-beam adaptive array was used. A simulation package was used in the evaluation of multi-beam systems using more than three beams and different user-jammer scenarios. An attempt to further reduce the computation burden through continued analysis of maximum SJNR met with limited success. A method to acquire and track an incoming laser beam is proposed.

Experiment on a three-beam adaptive array for EHF frequency-hopped signals using a fast algorithm, phase E

NASA Astrophysics Data System (ADS)

Yen, J. L.; Kremer, P.; Fung, J.

1990-05-01

The Department of National Defence (Canada) has been conducting studies into multi-beam adaptive arrays for extremely high frequency (EHF) frequency hopped signals. A three-beam 43 GHz adaptive antenna and a beam control processor is under development. An interactive software package for the operation of the array, capable of applying different control algorithms is being written. A maximum signal to jammer plus noise ratio (SJNR) has been found to provide superior performance in preventing degradation of user signals in the presence of nearby jammers. A new fast algorithm using a modified conjugate gradient approach has been found to be a very efficient way to implement anti-jamming arrays based on maximum SJNR criterion. The present study was intended to refine and simplify this algorithm and to implement the algorithm on an experimental array for real-time evaluation of anti-jamming performance. A three-beam adaptive array was used. A simulation package was used in the evaluation of multi-beam systems using more than three beams and different user-jammer scenarios. An attempt to further reduce the computation burden through further analysis of maximum SJNR met with limited success. The investigation of a new angle detector for spatial tracking in heterodyne laser space communications was completed.

Psychological First Aid

PubMed Central

Shultz, James M; Forbes, David

2014-01-01

Psychological first aid (PFA) has become the flagship early intervention for disaster survivors, with recent adaptations for disaster responders, in the post-9/11 era. PFA is broadly endorsed by expert consensus and integrated into guidelines for mental health and psychosocial support in disasters and extreme events. PFA frameworks are proliferating, with increasing numbers of models developed for delivery by a range of providers for use with an expanding array of target populations. Despite popularity and promotion there remains a dearth of evidence for effectiveness and recent independent reviews of PFA have highlighted this important gap. This commentary juxtaposes the current propagation of PFA against the compelling need to produce evidence for effectiveness and suggests a series of actions to prioritize and expedite real-time, real-event field evaluation of PFA. PMID:28228996

Psychological First Aid: Rapid proliferation and the search for evidence.

PubMed

Shultz, James M; Forbes, David

2014-01-01

Psychological first aid (PFA) has become the flagship early intervention for disaster survivors, with recent adaptations for disaster responders, in the post-9/11 era. PFA is broadly endorsed by expert consensus and integrated into guidelines for mental health and psychosocial support in disasters and extreme events. PFA frameworks are proliferating, with increasing numbers of models developed for delivery by a range of providers for use with an expanding array of target populations. Despite popularity and promotion there remains a dearth of evidence for effectiveness and recent independent reviews of PFA have highlighted this important gap. This commentary juxtaposes the current propagation of PFA against the compelling need to produce evidence for effectiveness and suggests a series of actions to prioritize and expedite real-time, real-event field evaluation of PFA.

Unstructured Adaptive Grid Computations on an Array of SMPs

NASA Technical Reports Server (NTRS)

Biswas, Rupak; Pramanick, Ira; Sohn, Andrew; Simon, Horst D.

1996-01-01

Dynamic load balancing is necessary for parallel adaptive methods to solve unsteady CFD problems on unstructured grids. We have presented such a dynamic load balancing framework called JOVE, in this paper. Results on a four-POWERnode POWER CHALLENGEarray demonstrated that load balancing gives significant performance improvements over no load balancing for such adaptive computations. The parallel speedup of JOVE, implemented using MPI on the POWER CHALLENCEarray, was significant, being as high as 31 for 32 processors. An implementation of JOVE that exploits 'an array of SMPS' architecture was also studied; this hybrid JOVE outperformed flat JOVE by up to 28% on the meshes and adaption models tested. With large, realistic meshes and actual flow-solver and adaption phases incorporated into JOVE, hybrid JOVE can be expected to yield significant advantage over flat JOVE, especially as the number of processors is increased, thus demonstrating the scalability of an array of SMPs architecture.

Self-Adaptive System based on Field Programmable Gate Array for Extreme Temperature Electronics

NASA Technical Reports Server (NTRS)

Keymeulen, Didier; Zebulum, Ricardo; Rajeshuni, Ramesham; Stoica, Adrian; Katkoori, Srinivas; Graves, Sharon; Novak, Frank; Antill, Charles

2006-01-01

In this work, we report the implementation of a self-adaptive system using a field programmable gate array (FPGA) and data converters. The self-adaptive system can autonomously recover the lost functionality of a reconfigurable analog array (RAA) integrated circuit (IC) [3]. Both the RAA IC and the self-adaptive system are operating in extreme temperatures (from 120 C down to -180 C). The RAA IC consists of reconfigurable analog blocks interconnected by several switches and programmable by bias voltages. It implements filters/amplifiers with bandwidth up to 20 MHz. The self-adaptive system controls the RAA IC and is realized on Commercial-Off-The-Shelf (COTS) parts. It implements a basic compensation algorithm that corrects a RAA IC in less than a few milliseconds. Experimental results for the cold temperature environment (down to -180 C) demonstrate the feasibility of this approach.

Target-in-the-loop high-power adaptive phase-locked fiber laser array using single-frequency dithering technique

NASA Astrophysics Data System (ADS)

Tao, R.; Ma, Y.; Si, L.; Dong, X.; Zhou, P.; Liu, Z.

2011-11-01

We present a theoretical and experimental study of a target-in-the-loop (TIL) high-power adaptive phase-locked fiber laser array. The system configuration of the TIL adaptive phase-locked fiber laser array is introduced, and the fundamental theory for TIL based on the single-dithering technique is deduced for the first time. Two 10-W-level high-power fiber amplifiers are set up and adaptive phase locking of the two fiber amplifiers is accomplished successfully by implementing a single-dithering algorithm on a signal processor. The experimental results demonstrate that the optical phase noise for each beam channel can be effectively compensated by the TIL adaptive optics system under high-power applications and the fringe contrast on a remotely located extended target is advanced from 12% to 74% for the two 10-W-level fiber amplifiers.

A three-component system incorporating Ppd-D1, copy number variation at Ppd-B1, and numerous small-effect quantitative trait loci facilitates adaptation of heading time in winter wheat cultivars of worldwide origin.

PubMed

Würschum, Tobias; Langer, Simon M; Longin, C Friedrich H; Tucker, Matthew R; Leiser, Willmar L

2018-06-01

The broad adaptability of heading time has contributed to the global success of wheat in a diverse array of climatic conditions. Here, we investigated the genetic architecture underlying heading time in a large panel of 1,110 winter wheat cultivars of worldwide origin. Genome-wide association mapping, in combination with the analysis of major phenology loci, revealed a three-component system that facilitates the adaptation of heading time in winter wheat. The photoperiod sensitivity locus Ppd-D1 was found to account for almost half of the genotypic variance in this panel and can advance or delay heading by many days. In addition, copy number variation at Ppd-B1 was the second most important source of variation in heading, explaining 8.3% of the genotypic variance. Results from association mapping and genomic prediction indicated that the remaining variation is attributed to numerous small-effect quantitative trait loci that facilitate fine-tuning of heading to the local climatic conditions. Collectively, our results underpin the importance of the two Ppd-1 loci for the adaptation of heading time in winter wheat and illustrate how the three components have been exploited for wheat breeding globally. © 2018 John Wiley & Sons Ltd.

Miniature curved artificial compound eyes

PubMed Central

Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L’Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A.; Franceschini, Nicolas

2013-01-01

In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories. PMID:23690574

Analysis of Modified SMI Method for Adaptive Array Weight Control. M.S. Thesis

NASA Technical Reports Server (NTRS)

Dilsavor, Ronald Louis

1989-01-01

An adaptive array is used to receive a desired signal in the presence of weak interference signals which need to be suppressed. A modified sample matrix inversion (SMI) algorithm controls the array weights. The modification leads to increased interference suppression by subtracting a fraction of the noise power from the diagonal elements of the covariance matrix. The modified algorithm maximizes an intuitive power ratio criterion. The expected values and variances of the array weights, output powers, and power ratios as functions of the fraction and the number of snapshots are found and compared to computer simulation and real experimental array performance. Reduced-rank covariance approximations and errors in the estimated covariance are also described.

Environmental photobioreactor array (EPBRA) systems and apparatus related thereto

DOEpatents

Kramer, David; Zegarac, Robert; Lucker, Ben F.; Hall, Christopher; Abernathy, Casey; Carpenter, Joel; Cruz, Jeffrey

2017-11-14

A system is described herein that comprises one or more modular environmental photobioreactor arrays, each array containing two or more photobioreactors, wherein the system is adapted to monitor each of the photobioreactors and/or modulate the conditions with each of the photobioreactors. The photobioreactors are also adapted for measurement of multiple physiological parameters of a biomass contained therein. Various methods for selecting and characterizing biomass are also provided. In one embodiment, the biomass is algae.

Space-Time Adaptive Processing for Airborne Radar

DTIC Science & Technology

1994-12-13

horizontal plane Uniform linear antenna array (possibly columns of a planar array) Identical element patterns 13 14 15 9 7 7,33 7 7 Target Model ...Parameters for Example Scenario 31 3 Assumptions Made for Radar System and Signal Model 52 4 Platform and Interference Scenario for Baseline Scenario. 61 5...pulses, is addressed first. Fully adaptive STAP requires the solution to a system of linear equations of size MN, where N is the number of array

The Astronomical Low Frequency Array: A Proposed Explorer Mission for Radio Astronomy

NASA Technical Reports Server (NTRS)

Jones, D.; Allen, R.; Basart, J.; Bastian, T.; Bougeret, J. L.; Dennison, B.; Desch, M.; Dwarakanath, K.; Erickson, W.; Finley, D.;

Genetic potential of black bean genotypes with predictable behaviors in multienvironment trials.

PubMed

Torga, P P; Melo, P G S; Pereira, H S; Faria, L C; Melo, L C

2016-10-24

The aim of this study was to evaluate the phenotypic stability and specific and broad adaptability of common black bean genotypes for the Central and Center-South regions of Brazil by using the Annicchiarico and AMMI (weighted average of absolute scores: WAAS, and weighted average of absolute scores and productivity: WAASP) methodologies. We carried out 69 trials, with 43 and 26 trials in the Central and Center-South regions, respectively. Thirteen genotypes were evaluated in a randomized block design with three replications, during the rainy, dry, and winter seasons in 2 years. To obtain estimates of specific adaptation, we analyzed the parameters for each method obtained in the two geographic regions separately. To estimate broad adaptation, we used the average of the parameters obtained from each region. The lines identified with high specific adaptation in each region were not the same based on the Annicchiarico and AMMI (WAAS) methodologies. It was not possible to identify the same genotypes with specific or broad stability by using these methods. By contrast, the Annicchiarico and AMMI (WAASP) methods presented very similar estimates of broad and specific adaptation. Based on these methods, the lines with more specific adaptation were CNFP 8000 and CNFP 7994, in the Central and Center-South regions, respectively, of which the CNFP 8000 line was more widely adapted.

Cost study of solar cell space power systems

NASA Technical Reports Server (NTRS)

Bernatowicz, D. T.

1972-01-01

Historical costs for solar cell space power systems were evaluated. The study covered thirteen missions that represented a broad cross section of flight projects over the past decade. Fully burdened costs in terms of 1971 dollars are presented for the system and the solar array. The costs correlate reasonably well with array area and do not increase in proportion to array area. The trends for array costs support the contention that solar cell and module standardization reduce costs.

Adaptive antenna arrays for weak interfering signals. [in satellite communication

NASA Technical Reports Server (NTRS)

Gupta, I. J.; Ksienski, A. A.

1986-01-01

It is shown that conventional adaptive arrays are unable to suppress weak interfering signals. To overcome this problem, the feedback loops controlling the array weights were modified, reducing the noise level by reducing the correlation between the noise components of the two inputs to the loop correlator. Various techniques to decorrelate these noise components are discussed. An expression is derived for the amount of noise decorrelation required to achieve a specified interference suppression. The results are of interest in connection with satellite communications.

Acoustic Wave Guiding by Reconfigurable Tessellated Arrays

NASA Astrophysics Data System (ADS)

Zou, Chengzhe; Lynd, Danielle T.; Harne, Ryan L.

2018-01-01

The reconfiguration of origami tessellations is a prime vehicle to harness for adapting system properties governed by a structural form. While the knowledge of mechanical property changes associated with origami tessellation folding has been extensively built up, the opportunities to integrate other physics into a framework of tessellated, adaptive structures remain to be fully exploited. Acoustics appears to be a prime domain to marry with origami science. Specifically, deep technical analogies are revealed between wave-guiding properties achieved via digital methods that virtually reposition array elements and the actual repositioning of facets by folding origami-inspired tessellations. Here we capitalize on this analogy to investigate acoustic arrays established upon facet layouts of origami-inspired tessellations. We show that a concept of reconfigurable tessellated arrays may guide waves more effectively than traditional digitally phased arrays using fewer transducer elements. Moreover, we show that the refinement of tessellated arrays trends to the ideal case of classical wave radiators or receivers grounded in principles of geometrical acoustics. By linear wave physics shared among myriad scientific disciplines and across orders of magnitude in length scale, these discoveries may cultivate numerous opportunities for wave-guiding adaptive structures inspired by low-dimensional origami tessellations.

Performance comparisons on spatial lattice algorithm and direct matrix inverse method with application to adaptive arrays processing

NASA Technical Reports Server (NTRS)

An, S. H.; Yao, K.

1986-01-01

Lattice algorithm has been employed in numerous adaptive filtering applications such as speech analysis/synthesis, noise canceling, spectral analysis, and channel equalization. In this paper the application to adaptive-array processing is discussed. The advantages are fast convergence rate as well as computational accuracy independent of the noise and interference conditions. The results produced by this technique are compared to those obtained by the direct matrix inverse method.

A multiplex culture system for the long‐term growth of fission yeast cells

PubMed Central

Callens, Céline; Coelho, Nelson C.; Miller, Aaron W.; Sananes, Maria Rosa Domingo; Dunham, Maitreya J.; Denoual, Matthieu

2017-01-01

Abstract Maintenance of long‐term cultures of yeast cells is central to a broad range of investigations, from metabolic studies to laboratory evolution assays. However, repeated dilutions of batch cultures lead to variations in medium composition, with implications for cell physiology. In Saccharomyces cerevisiae, powerful miniaturized chemostat setups, or ministat arrays, have been shown to allow for constant dilution of multiple independent cultures. Here we set out to adapt these arrays for continuous culture of a morphologically and physiologically distinct yeast, the fission yeast Schizosaccharomyces pombe, with the goal of maintaining constant population density over time. First, we demonstrated that the original ministats are incompatible with growing fission yeast for more than a few generations, prompting us to modify different aspects of the system design. Next, we identified critical parameters for sustaining unbiased vegetative growth in these conditions. This requires deletion of the gsf2 flocculin‐encoding gene, along with addition of galactose to the medium and lowering of the culture temperature. Importantly, we improved the flexibility of the ministats by developing a piezo‐pump module for the independent regulation of the dilution rate of each culture. This made it possible to easily grow strains that have different generation times in the same assay. Our system therefore allows for maintaining multiple fission yeast cultures in exponential growth, adapting the dilution of each culture over time to keep constant population density for hundreds of generations. These multiplex culture systems open the door to a new range of long‐term experiments using this model organism. © 2017 The Authors. Yeast published by John Wiley & Sons, Ltd. PMID:28426144

An SDR-Based Real-Time Testbed for GNSS Adaptive Array Anti-Jamming Algorithms Accelerated by GPU

PubMed Central

Xu, Hailong; Cui, Xiaowei; Lu, Mingquan

2016-01-01

Nowadays, software-defined radio (SDR) has become a common approach to evaluate new algorithms. However, in the field of Global Navigation Satellite System (GNSS) adaptive array anti-jamming, previous work has been limited due to the high computational power demanded by adaptive algorithms, and often lack flexibility and configurability. In this paper, the design and implementation of an SDR-based real-time testbed for GNSS adaptive array anti-jamming accelerated by a Graphics Processing Unit (GPU) are documented. This testbed highlights itself as a feature-rich and extendible platform with great flexibility and configurability, as well as high computational performance. Both Space-Time Adaptive Processing (STAP) and Space-Frequency Adaptive Processing (SFAP) are implemented with a wide range of parameters. Raw data from as many as eight antenna elements can be processed in real-time in either an adaptive nulling or beamforming mode. To fully take advantage of the parallelism resource provided by the GPU, a batched method in programming is proposed. Tests and experiments are conducted to evaluate both the computational and anti-jamming performance. This platform can be used for research and prototyping, as well as a real product in certain applications. PMID:26978363

An SDR-Based Real-Time Testbed for GNSS Adaptive Array Anti-Jamming Algorithms Accelerated by GPU.

PubMed

Xu, Hailong; Cui, Xiaowei; Lu, Mingquan

2016-03-11

Nowadays, software-defined radio (SDR) has become a common approach to evaluate new algorithms. However, in the field of Global Navigation Satellite System (GNSS) adaptive array anti-jamming, previous work has been limited due to the high computational power demanded by adaptive algorithms, and often lack flexibility and configurability. In this paper, the design and implementation of an SDR-based real-time testbed for GNSS adaptive array anti-jamming accelerated by a Graphics Processing Unit (GPU) are documented. This testbed highlights itself as a feature-rich and extendible platform with great flexibility and configurability, as well as high computational performance. Both Space-Time Adaptive Processing (STAP) and Space-Frequency Adaptive Processing (SFAP) are implemented with a wide range of parameters. Raw data from as many as eight antenna elements can be processed in real-time in either an adaptive nulling or beamforming mode. To fully take advantage of the parallelism resource provided by the GPU, a batched method in programming is proposed. Tests and experiments are conducted to evaluate both the computational and anti-jamming performance. This platform can be used for research and prototyping, as well as a real product in certain applications.

Analysis and experimental demonstration of conformal adaptive phase-locked fiber array for laser communications and beam projection applications

NASA Astrophysics Data System (ADS)

Liu, Ling

The primary goal of this research is the analysis, development, and experimental demonstration of an adaptive phase-locked fiber array system for free-space optical communications and laser beam projection applications. To our knowledge, the developed adaptive phase-locked system composed of three fiber collimators (subapertures) with tip-tilt wavefront phase control at each subaperture represents the first reported fiber array system that implements both phase-locking control and adaptive wavefront tip-tilt control capabilities. This research has also resulted in the following innovations: (a) The first experimental demonstration of a phase-locked fiber array with tip-tilt wave-front aberration compensation at each fiber collimator; (b) Development and demonstration of the fastest currently reported stochastic parallel gradient descent (SPGD) system capable of operation at 180,000 iterations per second; (c) The first experimental demonstration of a laser communication link based on a phase-locked fiber array; (d) The first successful experimental demonstration of turbulence and jitter-induced phase distortion compensation in a phase-locked fiber array optical system; (e) The first demonstration of laser beam projection onto an extended target with a randomly rough surface using a conformal adaptive fiber array system. Fiber array optical systems, the subject of this study, can overcome some of the draw-backs of conventional monolithic large-aperture transmitter/receiver optical systems that are usually heavy, bulky, and expensive. The primary experimental challenges in the development of the adaptive phased-locked fiber-array included precise (<5 microrad) alignment of the fiber collimators and development of fast (100kHz-class) phase-locking and wavefront tip-tilt control systems. The precise alignment of the fiber collimator array is achieved through a specially developed initial coarse alignment tool based on high precision piezoelectric picomotors and a dynamic fine alignment mechanism implemented with specially designed and manufactured piezoelectric fiber positioners. Phase-locking of the fiber collimators is performed by controlling the phases of the output beams (beamlets) using integrated polarization-maintaining (PM) fiber-coupled LiNbO3 phase shifters. The developed phase-locking controllers are based on either the SPGD algorithm or the multi-dithering technique. Subaperture wavefront phase tip-tilt control is realized using piezoelectric fiber positioners that are controlled using a computer-based SPGD controller. Both coherent (phase-locked) and incoherent beam combining in the fiber array system are analyzed theoretically and experimentally. Two special fiber-based beam-combining testbeds have been built to demonstrate the technical feasibility of phase-locking compensation prior to free-space operation. In addition, the reciprocity of counter-propagating beams in a phase-locked fiber array system has been investigated. Coherent beam combining in a phase-locking system with wavefront phase tip-tilt compensation at each subaperture is successfully demonstrated when laboratory-simulated turbulence and wavefront jitters are present in the propagation path of the beamlets. In addition, coherent beam combining with a non-cooperative extended target in the control loop is successfully demonstrated.

Graphene-based carbon-layered electrode array technology for neural imaging and optogenetic applications

PubMed Central

Park, Dong-Wook; Schendel, Amelia A.; Mikael, Solomon; Brodnick, Sarah K.; Richner, Thomas J.; Ness, Jared P.; Hayat, Mohammed R.; Atry, Farid; Frye, Seth T.; Pashaie, Ramin; Thongpang, Sanitta; Ma, Zhenqiang; Williams, Justin C.

2014-01-01

Neural micro-electrode arrays that are transparent over a broad wavelength spectrum from ultraviolet to infrared could allow for simultaneous electrophysiology and optical imaging, as well as optogenetic modulation of the underlying brain tissue. The long-term biocompatibility and reliability of neural micro-electrodes also require their mechanical flexibility and compliance with soft tissues. Here we present a graphene-based, carbon-layered electrode array (CLEAR) device, which can be implanted on the brain surface in rodents for high-resolution neurophysiological recording. We characterize optical transparency of the device at >90% transmission over the ultraviolet to infrared spectrum and demonstrate its utility through optical interface experiments that use this broad spectrum transparency. These include optogenetic activation of focal cortical areas directly beneath electrodes, in vivo imaging of the cortical vasculature via fluorescence microscopy and 3D optical coherence tomography. This study demonstrates an array of interfacing abilities of the CLEAR device and its utility for neural applications. PMID:25327513

Dynamic Adaptive Neural Network Arrays: A Neuromorphic Architecture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Disney, Adam; Reynolds, John

2015-01-01

Dynamic Adaptive Neural Network Array (DANNA) is a neuromorphic hardware implementation. It differs from most other neuromorphic projects in that it allows for programmability of structure, and it is trained or designed using evolutionary optimization. This paper describes the DANNA structure, how DANNA is trained using evolutionary optimization, and an application of DANNA to a very simple classification task.

System and method for cognitive processing for data fusion

NASA Technical Reports Server (NTRS)

Duong, Tuan A. (Inventor); Duong, Vu A. (Inventor)

2012-01-01

A system and method for cognitive processing of sensor data. A processor array receiving analog sensor data and having programmable interconnects, multiplication weights, and filters provides for adaptive learning in real-time. A static random access memory contains the programmable data for the processor array and the stored data is modified to provide for adaptive learning.

Laser beam projection with adaptive array of fiber collimators. II. Analysis of atmospheric compensation efficiency.

PubMed

Lachinova, Svetlana L; Vorontsov, Mikhail A

2008-08-01

We analyze the potential efficiency of laser beam projection onto a remote object in atmosphere with incoherent and coherent phase-locked conformal-beam director systems composed of an adaptive array of fiber collimators. Adaptive optics compensation of turbulence-induced phase aberrations in these systems is performed at each fiber collimator. Our analysis is based on a derived expression for the atmospheric-averaged value of the mean square residual phase error as well as direct numerical simulations. Operation of both conformal-beam projection systems is compared for various adaptive system configurations characterized by the number of fiber collimators, the adaptive compensation resolution, and atmospheric turbulence conditions.

Feedhorn-Coupled Transition-Edge Superconducting Bolometer Arrays for Cosmic Microwave Background Polarimetry

NASA Technical Reports Server (NTRS)

Hubmayr, J.; Austermann, J.; Beall, J.; Becker, D.; Cho, H.-M.; Datta, R.; Duff, S. M.; Grace, E.; Halverson, N.; Henderson, S. W.;

Adaptive Injection-locking Oscillator Array for RF Spectrum Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leung, Daniel

2011-04-19

A highly parallel radio frequency receiver using an array of injection-locking oscillators for on-chip, rapid estimation of signal amplitudes and frequencies is considered. The oscillators are tuned to different natural frequencies, and variable gain amplifiers are used to provide negative feedback to adapt the locking band-width with the input signal to yield a combined measure of input signal amplitude and frequency detuning. To further this effort, an array of 16 two-stage differential ring oscillators and 16 Gilbert-cell mixers is designed for 40-400 MHz operation. The injection-locking oscillator array is assembled on a custom printed-circuit board. Control and calibration is achievedmore » by on-board microcontroller.« less

Selection of common bean to broad environmental adaptation in Haiti

USDA-ARS?s Scientific Manuscript database

Common bean (Phaseolus vulgaris L.) cultivars in Haiti need adaptation to a broad range of environments and resistance to the most important diseases such as Bean Golden Yellow Mosaic Virus. The Legume Breeding Program (LBP), a collaborative effort of the AREA project (USAID funded through IFAS/Univ...

Origami acoustics: using principles of folding structural acoustics for simple and large focusing of sound energy

NASA Astrophysics Data System (ADS)

Harne, Ryan L.; Lynd, Danielle T.

2016-08-01

Fixed in spatial distribution, arrays of planar, electromechanical acoustic transducers cannot adapt their wave energy focusing abilities unless each transducer is externally controlled, creating challenges for the implementation and portability of such beamforming systems. Recently, planar, origami-based structural tessellations are found to facilitate great versatility in system function and properties through kinematic folding. In this research we bridge the physics of acoustics and origami-based design to discover that the simple topological reconfigurations of a Miura-ori-based acoustic array yield many orders of magnitude worth of reversible change in wave energy focusing: a potential for acoustic field morphing easily obtained through deployable, tessellated architectures. Our experimental and theoretical studies directly translate the roles of folding the tessellated array to the adaptations in spectral and spatial wave propagation sensitivities for far field energy transmission. It is shown that kinematic folding rules and flat-foldable tessellated arrays collectively provide novel solutions to the long-standing challenges of conventional, electronically-steered acoustic beamformers. While our examples consider sound radiation from the foldable array in air, linear acoustic reciprocity dictates that the findings may inspire new innovations for acoustic receivers, e.g. adaptive sound absorbers and microphone arrays, as well as concepts that include water-borne waves.

Designing Flat-Plate Photovoltaic Arrays

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1984-01-01

Report presents overview of state of art in design techniques for flat-plate solar photovoltaic modules and arrays. Paper discusses design requirements, design analyses, and test methods identified and developed for this technology over past several years in effort to reduce cost and improve utility and reliability for broad spectrum of terrestrial applications.

Cost study of solar cell space power systems.

NASA Technical Reports Server (NTRS)

Bernatowicz, D. T.

1972-01-01

A study of historical costs for solar cell space power systems was made by a NASA ad hoc study group. The study covered thirteen missions that represented a broad cross-section of flight projects over the past decade. Fully burdened costs in terms of 1971 dollars are presented for the system and the solar array. The costs correlate reasonably well with array area and do not increase in proportion to array area. The trends for array costs support the contention that solar cell and module standardization would reduce costs.

Parallel processing in a host plus multiple array processor system for radar

NASA Technical Reports Server (NTRS)

Barkan, B. Z.

1983-01-01

Host plus multiple array processor architecture is demonstrated to yield a modular, fast, and cost-effective system for radar processing. Software methodology for programming such a system is developed. Parallel processing with pipelined data flow among the host, array processors, and discs is implemented. Theoretical analysis of performance is made and experimentally verified. The broad class of problems to which the architecture and methodology can be applied is indicated.

Directional hearing aid using hybrid adaptive beamformer (HAB) and binaural ITE array

NASA Astrophysics Data System (ADS)

Shaw, Scott T.; Larow, Andy J.; Gibian, Gary L.; Sherlock, Laguinn P.; Schulein, Robert

2002-05-01

A directional hearing aid algorithm called the Hybrid Adaptive Beamformer (HAB), developed for NIH/NIA, can be applied to many different microphone array configurations. In this project the HAB algorithm was applied to a new array employing in-the-ear microphones at each ear (HAB-ITE), to see if previous HAB performance could be achieved with a more cosmetically acceptable package. With diotic output, the average benefit in threshold SNR was 10.9 dB for three HoH and 11.7 dB for five normal-hearing subjects. These results are slightly better than previous results of equivalent tests with a 3-in. array. With an innovative binaural fitting, a small benefit beyond that provided by diotic adaptive beamforming was observed: 12.5 dB for HoH and 13.3 dB for normal-hearing subjects, a 1.6 dB improvement over the diotic presentation. Subjectively, the binaural fitting preserved binaural hearing abilities, giving the user a sense of space, and providing left-right localization. Thus the goal of creating an adaptive beamformer that simultaneously provides excellent noise reduction and binaural hearing was achieved. Further work remains before the HAB-ITE can be incorporated into a real product, optimizing binaural adaptive beamforming, and integrating the concept with other technologies to produce a viable product prototype. [Work supported by NIH/NIDCD.

Parallel evolution of a type IV secretion system in radiating lineages of the host-restricted bacterial pathogen Bartonella.

PubMed

Engel, Philipp; Salzburger, Walter; Liesch, Marius; Chang, Chao-Chin; Maruyama, Soichi; Lanz, Christa; Calteau, Alexandra; Lajus, Aurélie; Médigue, Claudine; Schuster, Stephan C; Dehio, Christoph

2011-02-10

Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS), and thereby translocated Bartonella effector proteins (Beps), evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial pathogens. Furthermore, our study highlights the remarkable evolvability of T4SSs and their effector proteins, explaining their broad application in bacterial interactions with the environment.

Parallel Evolution of a Type IV Secretion System in Radiating Lineages of the Host-Restricted Bacterial Pathogen Bartonella

PubMed Central

Engel, Philipp; Salzburger, Walter; Liesch, Marius; Chang, Chao-Chin; Maruyama, Soichi; Lanz, Christa; Calteau, Alexandra; Lajus, Aurélie; Médigue, Claudine; Schuster, Stephan C.; Dehio, Christoph

2011-01-01

Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS), and thereby translocated Bartonella effector proteins (Beps), evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial pathogens. Furthermore, our study highlights the remarkable evolvability of T4SSs and their effector proteins, explaining their broad application in bacterial interactions with the environment. PMID:21347280

The split personality of NKT cells in malignancy, autoimmune and allergic disorders

PubMed Central

Subleski, Jeff J; Jiang, Qun; Weiss, Jonathan M; Wiltrout, Robert H

2011-01-01

NKT cells are a heterogeneous subset of specialized, self-reactive T cells, with innate and adaptive immune properties, which allow them to bridge innate and adaptive immunity and profoundly influence autoimmune and malignant disease outcomes. NKT cells mediate these activities through their ability to rapidly express pro- and anti-inflammatory cytokines that influence the type and magnitude of the immune response. Not only do NKT cells regulate the functions of other cell types, but experimental evidence has found NKT cell subsets can modulate the functions of other NKT subsets. Depending on underlying mechanisms, NKT cells can inhibit or exacerbate autoimmunity and malignancy, making them potential targets for disease intervention. NKT cells can respond to foreign and endogenous antigenic glycolipid signals that are expressed during pathogenic invasion or ongoing inflammation, respectively, allowing them to rapidly react to and influence a broad array of diseases. In this article we review the unique development and activation pathways of NKT cells and focus on how these attributes augment or exacerbate autoimmune disorders and malignancy. We also examine the growing evidence that NKT cells are involved in liver inflammatory conditions that can contribute to the development of malignancy. PMID:21995570

Hypoxia tolerance in reptiles, amphibians, and fishes: life with variable oxygen availability.

PubMed

Bickler, Philip E; Buck, Leslie T

2007-01-01

The ability of fishes, amphibians, and reptiles to survive extremes of oxygen availability derives from a core triad of adaptations: profound metabolic suppression, tolerance of ionic and pH disturbances, and mechanisms for avoiding free-radical injury during reoxygenation. For long-term anoxic survival, enhanced storage of glycogen in critical tissues is also necessary. The diversity of body morphologies and habitats and the utilization of dormancy have resulted in a broad array of adaptations to hypoxia in lower vertebrates. For example, the most anoxia-tolerant vertebrates, painted turtles and crucian carp, meet the challenge of variable oxygen in fundamentally different ways: Turtles undergo near-suspended animation, whereas carp remain active and responsive in the absence of oxygen. Although the mechanisms of survival in both of these cases include large stores of glycogen and drastically decreased metabolism, other mechanisms, such as regulation of ion channels in excitable membranes, are apparently divergent. Common themes in the regulatory adjustments to hypoxia involve control of metabolism and ion channel conductance by protein phosphorylation. Tolerance of decreased energy charge and accumulating anaerobic end products as well as enhanced antioxidant defenses and regenerative capacities are also key to hypoxia survival in lower vertebrates.

Adapter plate assembly for adjustable mounting of objects

DOEpatents

Blackburn, R.S.

1986-05-02

An adapter plate and two locking discs are together affixed to an optic table with machine screws or bolts threaded into a fixed array of internally threaded holes provided in the table surface. The adapter plate preferably has two, and preferably parallel, elongated locating slots each freely receiving a portion of one of the locking discs for secure affixation of the adapter plate to the optic table. A plurality of threaded apertures provided in the adapter plate are available to attach optical mounts or other devices onto the adapter plate in an orientation not limited by the disposition of the array of threaded holes in the table surface. An axially aligned but radially offset hole through each locking disc receives a screw that tightens onto the table, such that prior to tightening of the screw the locking disc may rotate and translate within each locating slot of the adapter plate for maximum flexibility of the orientation thereof.

Adapter plate assembly for adjustable mounting of objects

DOEpatents

Blackburn, Robert S.

1987-01-01

An adapter plate and two locking discs are together affixed to an optic table with machine screws or bolts threaded into a fixed array of internally threaded holes provided in the table surface. The adapter plate preferably has two, and preferably parallel, elongated locating slots each freely receiving a portion of one of the locking discs for secure affixation of the adapter plate to the optic table. A plurality of threaded apertures provided in the adapter plate are available to attach optical mounts or other devices onto the adapter plate in an orientation not limited by the disposition of the array of threaded holes in the table surface. An axially aligned but radially offset hole through each locking disc receives a screw that tightens onto the table, such that prior to tightening of the screw the locking disc may rotate and translate within each locating slot of the adapter plate for maximum flexibility of the orientation thereof.

Climate Change in the Arctic, Moving from Acceptance to Adaptation (Invited)

NASA Astrophysics Data System (ADS)

Hinzman, L. D.

2009-12-01

In Alaska, we no longer discuss climate change using words such as “possible” or “potential”. It has arrived. There is ample evidence of impacts from a changing climate in Alaska, primarily due to the predominance of snow, ice and permafrost. The presence or absence of frozen ground or water will dominate the local ecology, hydrology, physical characteristics and surface energy balance. As the soil or ice progresses through thawing, threshold changes occur that may initiate a cascade of events resulting in substantial changes to the regional character. If one examines any individual scientific discipline, evidence of climate change in arctic regions offers only pieces of the puzzle. This presentation will include a broad array of evidence to provide a convincing case of change in the arctic climate and a system-wide response of terrestrial processes. The thermal regime of the Arctic holds unique characteristics and consequently will display marked changes in response to climate warming. In many cases, threshold changes will occur in physical systems proceeding from permanently frozen to periodically thawed. Dramatic changes also accompany biological systems adapting to an evolving environment. It is expected that the effects and consequences of a warming climate will become even more evident within the next 10 to 50 years so our society must now consider actions related to adaptation and preparation for change.

Multichannel signal enhancement

DOEpatents

Lewis, Paul S.

1990-01-01

A mixed adaptive filter is formulated for the signal processing problem where desired a priori signal information is not available. The formulation generates a least squares problem which enables the filter output to be calculated directly from an input data matrix. In one embodiment, a folded processor array enables bidirectional data flow to solve the recursive problem by back substitution without global communications. In another embodiment, a balanced processor array solves the recursive problem by forward elimination through the array. In a particular application to magnetoencephalography, the mixed adaptive filter enables an evoked response to an auditory stimulus to be identified from only a single trial.

Total variation approach for adaptive nonuniformity correction in focal-plane arrays.

PubMed

Vera, Esteban; Meza, Pablo; Torres, Sergio

2011-01-15

In this Letter we propose an adaptive scene-based nonuniformity correction method for fixed-pattern noise removal in imaging arrays. It is based on the minimization of the total variation of the estimated irradiance, and the resulting function is optimized by an isotropic total variation approach making use of an alternating minimization strategy. The proposed method provides enhanced results when applied to a diverse set of real IR imagery, accurately estimating the nonunifomity parameters of each detector in the focal-plane array at a fast convergence rate, while also forming fewer ghosting artifacts.

Development of adaptive liquid microlenses and microlens arrays

NASA Astrophysics Data System (ADS)

Berry, Shaun R.; Stewart, Jason B.; Thorsen, Todd A.; Guha, Ingrid

2013-03-01

We report on the development of sub-millimeter size adaptive liquid microlenses and microlens arrays using two immiscible liquids to form individual lenses. Microlenses and microlens arrays having aperture diameters as small as 50 microns were fabricated on a planar quartz substrate using patterned hydrophobic/hydrophilic regions. Liquid lenses were formed by a self-assembled oil dosing process that created well-defined lenses having a high fill factor. Variable focus was achieved by controlling the lens curvature through electrowetting. Greater than 70° of contact angle change was achieved with less than 20 volts, which results in a large optical power dynamic range.

High-speed on-chip windowed centroiding using photodiode-based CMOS imager

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor); Sun, Chao (Inventor); Yang, Guang (Inventor); Cunningham, Thomas J. (Inventor); Hancock, Bruce (Inventor)

2003-01-01

A centroid computation system is disclosed. The system has an imager array, a switching network, computation elements, and a divider circuit. The imager array has columns and rows of pixels. The switching network is adapted to receive pixel signals from the image array. The plurality of computation elements operates to compute inner products for at least x and y centroids. The plurality of computation elements has only passive elements to provide inner products of pixel signals the switching network. The divider circuit is adapted to receive the inner products and compute the x and y centroids.

High-speed on-chip windowed centroiding using photodiode-based CMOS imager

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor); Sun, Chao (Inventor); Yang, Guang (Inventor); Cunningham, Thomas J. (Inventor); Hancock, Bruce (Inventor)

2004-01-01

A centroid computation system is disclosed. The system has an imager array, a switching network, computation elements, and a divider circuit. The imager array has columns and rows of pixels. The switching network is adapted to receive pixel signals from the image array. The plurality of computation elements operates to compute inner products for at least x and y centroids. The plurality of computation elements has only passive elements to provide inner products of pixel signals the switching network. The divider circuit is adapted to receive the inner products and compute the x and y centroids.

Resolution doubling in fluorescence microscopy with confocal spinning-disk image scanning microscopy.

PubMed

Schulz, Olaf; Pieper, Christoph; Clever, Michaela; Pfaff, Janine; Ruhlandt, Aike; Kehlenbach, Ralph H; Wouters, Fred S; Großhans, Jörg; Bunt, Gertrude; Enderlein, Jörg

2013-12-24

We demonstrate how a conventional confocal spinning-disk (CSD) microscope can be converted into a doubly resolving image scanning microscopy (ISM) system without changing any part of its optical or mechanical elements. Making use of the intrinsic properties of a CSD microscope, we illuminate stroboscopically, generating an array of excitation foci that are moved across the sample by varying the phase between stroboscopic excitation and rotation of the spinning disk. ISM then generates an image with nearly doubled resolution. Using conventional fluorophores, we have imaged single nuclear pore complexes in the nuclear membrane and aggregates of GFP-conjugated Tau protein in three dimensions. Multicolor ISM was shown on cytoskeletal-associated structural proteins and on 3D four-color images including MitoTracker and Hoechst staining. The simple adaptation of conventional CSD equipment allows superresolution investigations of a broad variety of cell biological questions.

Resolution doubling in fluorescence microscopy with confocal spinning-disk image scanning microscopy

PubMed Central

Schulz, Olaf; Pieper, Christoph; Clever, Michaela; Pfaff, Janine; Ruhlandt, Aike; Kehlenbach, Ralph H.; Wouters, Fred S.; Großhans, Jörg; Bunt, Gertrude; Enderlein, Jörg

2013-01-01

We demonstrate how a conventional confocal spinning-disk (CSD) microscope can be converted into a doubly resolving image scanning microscopy (ISM) system without changing any part of its optical or mechanical elements. Making use of the intrinsic properties of a CSD microscope, we illuminate stroboscopically, generating an array of excitation foci that are moved across the sample by varying the phase between stroboscopic excitation and rotation of the spinning disk. ISM then generates an image with nearly doubled resolution. Using conventional fluorophores, we have imaged single nuclear pore complexes in the nuclear membrane and aggregates of GFP-conjugated Tau protein in three dimensions. Multicolor ISM was shown on cytoskeletal-associated structural proteins and on 3D four-color images including MitoTracker and Hoechst staining. The simple adaptation of conventional CSD equipment allows superresolution investigations of a broad variety of cell biological questions. PMID:24324140

Basic science for the clinician 53: mast cells.

PubMed

Sigal, Leonard H

2011-10-01

Mast cells stand at the interface between the innate immune system and the acquired (adaptive) immune response, serving as sentinels detecting invaders and directing a concerted and coordinated response. Mast cells reside immediately under body surfaces and within lymph nodes, near blood vessels and nerves, perfectly situated to for early detection and defense. They secrete a wide array of prostanoids, cytokines, chemokines, and other proteins mediators and modifiers of a variety of immune and inflammatory functions and bear surface markers suggesting broad functions, including as antigen-presenting cells. Although usually not given their due in medical school lectures, there is great likelihood that mast cells will be implicated in the pathogenesis of rheumatoid arthritis, scleroderma, multiple sclerosis, and perhaps cancer. Thus, better insights into mast cell functions and mast cell-derived effector molecules should command our attention as we move forward in better understanding disease immunopathogenesis and directed intelligent therapeutics development.

Three-dimensional mapping and regulation of action potential propagation in nanoelectronics innervated tissues

PubMed Central

Dai, Xiaochuan; Zhou, Wei; Gao, Teng; Liu, Jia; Lieber, Charles M.

2016-01-01

Real-time mapping and manipulation of electrophysiology in three-dimensional (3D) tissues could impact broadly fundamental scientific and clinical studies, yet realization lacks effective methods. Here we introduce tissue-scaffold-mimicking 3D nanoelectronic arrays consisting of 64 addressable devices with subcellular dimensions and sub-millisecond time-resolution. Real-time extracellular action potential (AP) recordings reveal quantitative maps of AP propagation in 3D cardiac tissues, enable in situ tracing of the evolving topology of 3D conducting pathways in developing cardiac tissues, and probe the dynamics of AP conduction characteristics in a transient arrhythmia disease model and subsequent tissue self-adaptation. We further demonstrate simultaneous multi-site stimulation and mapping to manipulate actively the frequency and direction of AP propagation. These results establish new methodologies for 3D spatiotemporal tissue recording and control, and demonstrate the potential to impact regenerative medicine, pharmacology and electronic therapeutics. PMID:27347837

Microwave performance characterization of large space antennas

NASA Technical Reports Server (NTRS)

Bathker, D. A. (Editor)

1977-01-01

Performance capabilities of large microwave space antenna configurations with apertures generally from 100 wavelengths upwards are discussed. Types of antennas considered include: phased arrays, lenses, reflectors, and hybrid combinations of phased arrays with reflectors or lenses. The performance characteristics of these broad classes of antennas are examined and compared in terms of applications.

A user-friendly workflow for analysis of Illumina gene expression bead array data available at the arrayanalysis.org portal.

PubMed

Eijssen, Lars M T; Goelela, Varshna S; Kelder, Thomas; Adriaens, Michiel E; Evelo, Chris T; Radonjic, Marijana

2015-06-30

Illumina whole-genome expression bead arrays are a widely used platform for transcriptomics. Most of the tools available for the analysis of the resulting data are not easily applicable by less experienced users. ArrayAnalysis.org provides researchers with an easy-to-use and comprehensive interface to the functionality of R and Bioconductor packages for microarray data analysis. As a modular open source project, it allows developers to contribute modules that provide support for additional types of data or extend workflows. To enable data analysis of Illumina bead arrays for a broad user community, we have developed a module for ArrayAnalysis.org that provides a free and user-friendly web interface for quality control and pre-processing for these arrays. This module can be used together with existing modules for statistical and pathway analysis to provide a full workflow for Illumina gene expression data analysis. The module accepts data exported from Illumina's GenomeStudio, and provides the user with quality control plots and normalized data. The outputs are directly linked to the existing statistics module of ArrayAnalysis.org, but can also be downloaded for further downstream analysis in third-party tools. The Illumina bead arrays analysis module is available at http://www.arrayanalysis.org . A user guide, a tutorial demonstrating the analysis of an example dataset, and R scripts are available. The module can be used as a starting point for statistical evaluation and pathway analysis provided on the website or to generate processed input data for a broad range of applications in life sciences research.

Study of large adaptive arrays for space technology applications

NASA Technical Reports Server (NTRS)

Berkowitz, R. S.; Steinberg, B.; Powers, E.; Lim, T.

1977-01-01

The research in large adaptive antenna arrays for space technology applications is reported. Specifically two tasks were considered. The first was a system design study for accurate determination of the positions and the frequencies of sources radiating from the earth's surface that could be used for the rapid location of people or vehicles in distress. This system design study led to a nonrigid array about 8 km in size with means for locating the array element positions, receiving signals from the earth and determining the source locations and frequencies of the transmitting sources. It is concluded that this system design is feasible, and satisfies the desired objectives. The second task was an experiment to determine the largest earthbound array which could simulate a spaceborne experiment. It was determined that an 800 ft array would perform indistinguishably in both locations and it is estimated that one several times larger also would serve satisfactorily. In addition the power density spectrum of the phase difference fluctuations across a large array was measured. It was found that the spectrum falls off approximately as f to the minus 5/2 power.

Adaptive Arrays for Weak Interfering Signals: An Experimental System. M.S. Thesis

NASA Technical Reports Server (NTRS)

Ward, James

1987-01-01

An experimental adaptive antenna system was implemented to study the performance of adaptive arrays in the presence of weak interfering signals. It is a sidelobe canceler with two auxiliary elements. Modified feedback loops, which decorrelate the noise components of the two inputs to the loop correlators, control the array weights. Digital processing is used for algorithm implementation and performance evaluation. The results show that the system can suppress interfering signals which are 0 to 10 dB below the thermal noise level in the main channel by 20 to 30 dB. When the desired signal is strong in the auxiliary elements the amount of interference suppression decreases. The amount of degradation depends on the number of interfering signals incident on the communication system. A modified steering vector which overcomes this problem is proposed.

On-line Machine Learning and Event Detection in Petascale Data Streams

NASA Astrophysics Data System (ADS)

Thompson, David R.; Wagstaff, K. L.

2012-01-01

Traditional statistical data mining involves off-line analysis in which all data are available and equally accessible. However, petascale datasets have challenged this premise since it is often impossible to store, let alone analyze, the relevant observations. This has led the machine learning community to investigate adaptive processing chains where data mining is a continuous process. Here pattern recognition permits triage and followup decisions at multiple stages of a processing pipeline. Such techniques can also benefit new astronomical instruments such as the Large Synoptic Survey Telescope (LSST) and Square Kilometre Array (SKA) that will generate petascale data volumes. We summarize some machine learning perspectives on real time data mining, with representative cases of astronomical applications and event detection in high volume datastreams. The first is a "supervised classification" approach currently used for transient event detection at the Very Long Baseline Array (VLBA). It injects known signals of interest - faint single-pulse anomalies - and tunes system parameters to recover these events. This permits meaningful event detection for diverse instrument configurations and observing conditions whose noise cannot be well-characterized in advance. Second, "semi-supervised novelty detection" finds novel events based on statistical deviations from previous patterns. It detects outlier signals of interest while considering known examples of false alarm interference. Applied to data from the Parkes pulsar survey, the approach identifies anomalous "peryton" phenomena that do not match previous event models. Finally, we consider online light curve classification that can trigger adaptive followup measurements of candidate events. Classifier performance analyses suggest optimal survey strategies, and permit principled followup decisions from incomplete data. These examples trace a broad range of algorithm possibilities available for online astronomical data mining. This talk describes research performed at the Jet Propulsion Laboratory, California Institute of Technology. Copyright 2012, All Rights Reserved. U.S. Government support acknowledged.

A multiplex culture system for the long-term growth of fission yeast cells.

PubMed

Callens, Céline; Coelho, Nelson C; Miller, Aaron W; Sananes, Maria Rosa Domingo; Dunham, Maitreya J; Denoual, Matthieu; Coudreuse, Damien

2017-08-01

Maintenance of long-term cultures of yeast cells is central to a broad range of investigations, from metabolic studies to laboratory evolution assays. However, repeated dilutions of batch cultures lead to variations in medium composition, with implications for cell physiology. In Saccharomyces cerevisiae, powerful miniaturized chemostat setups, or ministat arrays, have been shown to allow for constant dilution of multiple independent cultures. Here we set out to adapt these arrays for continuous culture of a morphologically and physiologically distinct yeast, the fission yeast Schizosaccharomyces pombe, with the goal of maintaining constant population density over time. First, we demonstrated that the original ministats are incompatible with growing fission yeast for more than a few generations, prompting us to modify different aspects of the system design. Next, we identified critical parameters for sustaining unbiased vegetative growth in these conditions. This requires deletion of the gsf2 flocculin-encoding gene, along with addition of galactose to the medium and lowering of the culture temperature. Importantly, we improved the flexibility of the ministats by developing a piezo-pump module for the independent regulation of the dilution rate of each culture. This made it possible to easily grow strains that have different generation times in the same assay. Our system therefore allows for maintaining multiple fission yeast cultures in exponential growth, adapting the dilution of each culture over time to keep constant population density for hundreds of generations. These multiplex culture systems open the door to a new range of long-term experiments using this model organism. © 2017 The Authors. Yeast published by John Wiley & Sons, Ltd. © 2017 The Authors. Yeast published by John Wiley & Sons, Ltd.

Micromirror Arrays for Adaptive Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carr, E.J.

The long-range goal of this project is to develop the optical and mechanical design of a micromirror array for adaptive optics that will meet the following criteria: flat mirror surface ({lambda}/20), high fill factor (> 95%), large stroke (5-10 {micro}m), and pixel size {approx}-200 {micro}m. This will be accomplished by optimizing the mirror surface and actuators independently and then combining them using bonding technologies that are currently being developed.

Principles of Adaptive Array Processing

DTIC Science & Technology

2006-09-01

ACE with and without tapering (homogeneous case). These analytical results are less suited to predict the detection performance of a real system ...Nickel: Adaptive Beamforming for Phased Array Radars. Proc. Int. Radar Symposium IRS’98 (Munich, Sept. 1998), DGON and VDE /ITG, pp. 897-906.(Reprint also...strategies for airborne radar. Asilomar Conf. on Signals, Systems and Computers, Pacific Grove, CA, 1998, IEEE Cat.Nr. 0-7803-5148-7/98, pp. 1327-1331. [17

Adaptive multibeam phased array design for a Spacelab experiment

NASA Technical Reports Server (NTRS)

Noji, T. T.; Fass, S.; Fuoco, A. M.; Wang, C. D.

1977-01-01

The parametric tradeoff analyses and design for an Adaptive Multibeam Phased Array (AMPA) for a Spacelab experiment are described. This AMPA Experiment System was designed with particular emphasis to maximize channel capacity and minimize implementation and cost impacts for future austere maritime and aeronautical users, operating with a low gain hemispherical coverage antenna element, low effective radiated power, and low antenna gain-to-system noise temperature ratio.

Reconfigurable signal processor designs for advanced digital array radar systems

NASA Astrophysics Data System (ADS)

Suarez, Hernan; Zhang, Yan (Rockee); Yu, Xining

2017-05-01

The new challenges originated from Digital Array Radar (DAR) demands a new generation of reconfigurable backend processor in the system. The new FPGA devices can support much higher speed, more bandwidth and processing capabilities for the need of digital Line Replaceable Unit (LRU). This study focuses on using the latest Altera and Xilinx devices in an adaptive beamforming processor. The field reprogrammable RF devices from Analog Devices are used as analog front end transceivers. Different from other existing Software-Defined Radio transceivers on the market, this processor is designed for distributed adaptive beamforming in a networked environment. The following aspects of the novel radar processor will be presented: (1) A new system-on-chip architecture based on Altera's devices and adaptive processing module, especially for the adaptive beamforming and pulse compression, will be introduced, (2) Successful implementation of generation 2 serial RapidIO data links on FPGA, which supports VITA-49 radio packet format for large distributed DAR processing. (3) Demonstration of the feasibility and capabilities of the processor in a Micro-TCA based, SRIO switching backplane to support multichannel beamforming in real-time. (4) Application of this processor in ongoing radar system development projects, including OU's dual-polarized digital array radar, the planned new cylindrical array radars, and future airborne radars.

A real-time regional adaptive exposure method for saving dose-area product in x-ray fluoroscopy

PubMed Central

Burion, Steve; Speidel, Michael A.; Funk, Tobias

2013-01-01

Purpose: Reduction of radiation dose in x-ray imaging has been recognized as a high priority in the medical community. Here the authors show that a regional adaptive exposure method can reduce dose-area product (DAP) in x-ray fluoroscopy. The authors' method is particularly geared toward providing dose savings for the pediatric population. Methods: The scanning beam digital x-ray system uses a large-area x-ray source with 8000 focal spots in combination with a small photon-counting detector. An imaging frame is obtained by acquiring and reconstructing up to 8000 detector images, each viewing only a small portion of the patient. Regional adaptive exposure was implemented by varying the exposure of the detector images depending on the local opacity of the object. A family of phantoms ranging in size from infant to obese adult was imaged in anteroposterior view with and without adaptive exposure. The DAP delivered to each phantom was measured in each case, and noise performance was compared by generating noise arrays to represent regional noise in the images. These noise arrays were generated by dividing the image into regions of about 6 mm2, calculating the relative noise in each region, and placing the relative noise value of each region in a one-dimensional array (noise array) sorted from highest to lowest. Dose-area product savings were calculated as the difference between the ratio of DAP with adaptive exposure to DAP without adaptive exposure. The authors modified this value by a correction factor that matches the noise arrays where relative noise is the highest to report a final dose-area product savings. Results: The average dose-area product saving across the phantom family was (42 ± 8)% with the highest dose-area product saving in the child-sized phantom (50%) and the lowest in the phantom mimicking an obese adult (23%). Conclusions: Phantom measurements indicate that a regional adaptive exposure method can produce large DAP savings without compromising the noise performance in the image regions with highest noise. PMID:23635281

Coherent-subspace array processing based on wavelet covariance: an application to broad-band, seismo-volcanic signals

NASA Astrophysics Data System (ADS)

Saccorotti, G.; Nisii, V.; Del Pezzo, E.

2008-07-01

Long-Period (LP) and Very-Long-Period (VLP) signals are the most characteristic seismic signature of volcano dynamics, and provide important information about the physical processes occurring in magmatic and hydrothermal systems. These events are usually characterized by sharp spectral peaks, which may span several frequency decades, by emergent onsets, and by a lack of clear S-wave arrivals. These two latter features make both signal detection and location a challenging task. In this paper, we propose a processing procedure based on Continuous Wavelet Transform of multichannel, broad-band data to simultaneously solve the signal detection and location problems. Our method consists of two steps. First, we apply a frequency-dependent threshold to the estimates of the array-averaged WCO in order to locate the time-frequency regions spanned by coherent arrivals. For these data, we then use the time-series of the complex wavelet coefficients for deriving the elements of the spatial Cross-Spectral Matrix. From the eigenstructure of this matrix, we eventually estimate the kinematic signals' parameters using the MUltiple SIgnal Characterization (MUSIC) algorithm. The whole procedure greatly facilitates the detection and location of weak, broad-band signals, in turn avoiding the time-frequency resolution trade-off and frequency leakage effects which affect conventional covariance estimates based upon Windowed Fourier Transform. The method is applied to explosion signals recorded at Stromboli volcano by either a short-period, small aperture antenna, or a large-aperture, broad-band network. The LP (0.2 < T < 2s) components of the explosive signals are analysed using data from the small-aperture array and under the plane-wave assumption. In this manner, we obtain a precise time- and frequency-localization of the directional properties for waves impinging at the array. We then extend the wavefield decomposition method using a spherical wave front model, and analyse the VLP components (T > 2s) of the explosion recordings from the broad-band network. Source locations obtained this way are fully compatible with those retrieved from application of more traditional (and computationally expensive) time-domain techniques, such as the Radial Semblance method.

A performance analysis of advanced I/O architectures for PC-based network file servers

NASA Astrophysics Data System (ADS)

Huynh, K. D.; Khoshgoftaar, T. M.

1994-12-01

In the personal computing and workstation environments, more and more I/O adapters are becoming complete functional subsystems that are intelligent enough to handle I/O operations on their own without much intervention from the host processor. The IBM Subsystem Control Block (SCB) architecture has been defined to enhance the potential of these intelligent adapters by defining services and conventions that deliver command information and data to and from the adapters. In recent years, a new storage architecture, the Redundant Array of Independent Disks (RAID), has been quickly gaining acceptance in the world of computing. In this paper, we would like to discuss critical system design issues that are important to the performance of a network file server. We then present a performance analysis of the SCB architecture and disk array technology in typical network file server environments based on personal computers (PCs). One of the key issues investigated in this paper is whether a disk array can outperform a group of disks (of same type, same data capacity, and same cost) operating independently, not in parallel as in a disk array.

Ultrasonic Imaging in Solids Using Wave Mode Beamforming.

PubMed

di Scalea, Francesco Lanza; Sternini, Simone; Nguyen, Thompson Vu

2017-03-01

This paper discusses some improvements to ultrasonic synthetic imaging in solids with primary applications to nondestructive testing of materials and structures. Specifically, the study proposes new adaptive weights applied to the beamforming array that are based on the physics of the propagating waves, specifically the displacement structure of the propagating longitudinal (L) mode and shear (S) mode that are naturally coexisting in a solid. The wave mode structures can be combined with the wave geometrical spreading to better filter the array (in a matched filter approach) and improve its focusing ability compared to static array weights. This paper also proposes compounding, or summing, images obtained from the different wave modes to further improve the array gain without increasing its physical aperture. The wave mode compounding can be performed either incoherently or coherently, in analogy with compounding multiple frequencies or multiple excitations. Numerical simulations and experimental testing demonstrate the potential improvements obtainable by the wave structure adaptive weights compared to either static weights in conventional delay-and-sum focusing, or adaptive weights based on geometrical spreading alone in minimum-variance distortionless response focusing.

Improvement of resolution in full-view linear-array photoacoustic computed tomography using a novel adaptive weighting method

NASA Astrophysics Data System (ADS)

Omidi, Parsa; Diop, Mamadou; Carson, Jeffrey; Nasiriavanaki, Mohammadreza

2017-03-01

Linear-array-based photoacoustic computed tomography is a popular methodology for deep and high resolution imaging. However, issues such as phase aberration, side-lobe effects, and propagation limitations deteriorate the resolution. The effect of phase aberration due to acoustic attenuation and constant assumption of the speed of sound (SoS) can be reduced by applying an adaptive weighting method such as the coherence factor (CF). Utilizing an adaptive beamforming algorithm such as the minimum variance (MV) can improve the resolution at the focal point by eliminating the side-lobes. Moreover, invisibility of directional objects emitting parallel to the detection plane, such as vessels and other absorbing structures stretched in the direction perpendicular to the detection plane can degrade resolution. In this study, we propose a full-view array level weighting algorithm in which different weighs are assigned to different positions of the linear array based on an orientation algorithm which uses the histogram of oriented gradient (HOG). Simulation results obtained from a synthetic phantom show the superior performance of the proposed method over the existing reconstruction methods.

An Improved Adaptive Received Beamforming for Nested Frequency Offset and Nested Array FDA-MIMO Radar.

PubMed

Cheng, Sibei; Zhang, Qingjun; Bian, Mingming; Hao, Xinhong

2018-02-08

For the conventional FDA-MIMO (frequency diversity array multiple-input-multiple-output) Radar with uniform frequency offset and uniform linear array, the DOFs (degrees of freedom) of the adaptive beamformer are limited by the number of elements. A better performance-for example, a better suppression for strong interferences and a more desirable trade-off between the main lobe and side lobe-can be achieved with a greater number of DOFs. In order to obtain larger DOFs, this paper researches the signal model of the FDA-MIMO Radar with nested frequency offset and nested array, then proposes an improved adaptive beamforming method that uses the augmented matrix instead of the covariance matrix to calculate the optimum weight vectors and can be used to improve the output performances of FDA-MIMO Radar with the same element number or reduce the element number while maintain the approximate output performances such as the received beampattern, the main lobe width, side lobe depths and the output SINR (signal-to-interference-noise ratio). The effectiveness of the proposed scheme is verified by simulations.

An Improved Adaptive Received Beamforming for Nested Frequency Offset and Nested Array FDA-MIMO Radar

PubMed Central

Cheng, Sibei; Zhang, Qingjun; Bian, Mingming; Hao, Xinhong

2018-01-01

For the conventional FDA-MIMO (frequency diversity array multiple-input-multiple-output) Radar with uniform frequency offset and uniform linear array, the DOFs (degrees of freedom) of the adaptive beamformer are limited by the number of elements. A better performance—for example, a better suppression for strong interferences and a more desirable trade-off between the main lobe and side lobe—can be achieved with a greater number of DOFs. In order to obtain larger DOFs, this paper researches the signal model of the FDA-MIMO Radar with nested frequency offset and nested array, then proposes an improved adaptive beamforming method that uses the augmented matrix instead of the covariance matrix to calculate the optimum weight vectors and can be used to improve the output performances of FDA-MIMO Radar with the same element number or reduce the element number while maintain the approximate output performances such as the received beampattern, the main lobe width, side lobe depths and the output SINR (signal-to-interference-noise ratio). The effectiveness of the proposed scheme is verified by simulations. PMID:29419814

Emerging interdisciplinary fields in the coming intelligence/convergence era

NASA Astrophysics Data System (ADS)

Noor, Ahmed K.

2012-09-01

Dramatic advances are in the horizon resulting from rapid pace of development of several technologies, including, computing, communication, mobile, robotic, and interactive technologies. These advances, along with the trend towards convergence of traditional engineering disciplines with physical, life and other science disciplines will result in the development of new interdisciplinary fields, as well as in new paradigms for engineering practice in the coming intelligence/convergence era (post-information age). The interdisciplinary fields include Cyber Engineering, Living Systems Engineering, Biomechatronics/Robotics Engineering, Knowledge Engineering, Emergent/Complexity Engineering, and Multiscale Systems engineering. The paper identifies some of the characteristics of the intelligence/convergence era, gives broad definition of convergence, describes some of the emerging interdisciplinary fields, and lists some of the academic and other organizations working in these disciplines. The need is described for establishing a Hierarchical Cyber-Physical Ecosystem for facilitating interdisciplinary collaborations, and accelerating development of skilled workforce in the new fields. The major components of the ecosystem are listed. The new interdisciplinary fields will yield critical advances in engineering practice, and help in addressing future challenges in broad array of sectors, from manufacturing to energy, transportation, climate, and healthcare. They will also enable building large future complex adaptive systems-of-systems, such as intelligent multimodal transportation systems, optimized multi-energy systems, intelligent disaster prevention systems, and smart cities.

The Diversity of REcent and Ancient huMan (DREAM): A New Microarray for Genetic Anthropology and Genealogy, Forensics, and Personalized Medicine

PubMed Central

Yusuf, Leeban; Anderson, Ainan I J; Pirooznia, Mehdi; Arnellos, Dimitrios; Vilshansky, Gregory; Ercal, Gunes; Lu, Yontao; Webster, Teresa; Baird, Michael L; Esposito, Umberto

2017-01-01

Abstract The human population displays wide variety in demographic history, ancestry, content of DNA derived from hominins or ancient populations, adaptation, traits, copy number variation, drug response, and more. These polymorphisms are of broad interest to population geneticists, forensics investigators, and medical professionals. Historically, much of that knowledge was gained from population survey projects. Although many commercial arrays exist for genome-wide single-nucleotide polymorphism genotyping, their design specifications are limited and they do not allow a full exploration of biodiversity. We thereby aimed to design the Diversity of REcent and Ancient huMan (DREAM)—an all-inclusive microarray that would allow both identification of known associations and exploration of standing questions in genetic anthropology, forensics, and personalized medicine. DREAM includes probes to interrogate ancestry informative markers obtained from over 450 human populations, over 200 ancient genomes, and 10 archaic hominins. DREAM can identify 94% and 61% of all known Y and mitochondrial haplogroups, respectively, and was vetted to avoid interrogation of clinically relevant markers. To demonstrate its capabilities, we compared its FST distributions with those of the 1000 Genomes Project and commercial arrays. Although all arrays yielded similarly shaped (inverse J) FST distributions, DREAM’s autosomal and X-chromosomal distributions had the highest mean FST, attesting to its ability to discern subpopulations. DREAM performances are further illustrated in biogeographical, identical by descent, and copy number variation analyses. In summary, with approximately 800,000 markers spanning nearly 2,000 genes, DREAM is a useful tool for genetic anthropology, forensic, and personalized medicine studies. PMID:29165562

SU-C-204-02: Behavioral and Pathologic Differences in Mice Exposed to Proton Minibeam Arrays Versus Proton Broad Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eley, J; Zhang, C; Wolfe, T

Purpose: Minibeam therapy using protons or light-ions offers a theoretical reduction of biologic damage to tissues upstream of a tumor compared to broad-beam therapy while providing equal tumor control. The purpose of this study was to investigate behavioral and pathologic differences in mice after exposure of healthy brain to proton minibeam arrays versus proton broad beams. Methods: Twenty-four C57BL/6J juvenile mice were divided into 5 study arms: sham irradiation (NoRT), broad-beam 10 Gy (BB10), minibeam 10Gy (MB10), broad-beam 30 Gy (BB30), and minibeam 30 Gy (MB30), approximate integral entrance doses. Circular beams of 100 MeV protons with 7-mm diameter weremore » delivered laterally through the brain, either as broad beams or as planar minibeam arrays having 300-micron beam width and 1-mm spacing on center. Mice were followed for 8 months using standard behavioral tests. Pathologic studies were carried out at 8 months after irradiation. Results: Peak entrance doses were 10.0, 23.8, 30.0, and 71.3 Gy for mice in BB10, MB10, BB30, and MB30, respectively. Despite the high single-fraction doses, no animals showed signs of radiation sickness or neurophysical impairment over the 8-month study duration. The Morris water maze alternate-starting-position trial showed significant evidence of better spatial learning for mice in MB10 versus BB10 (p=0.026), but other behavioral tests showed no significant differences. Glial fibrillary acidic protein stains showed gliosis in arms BB10, BB30, and MB30 but not in NoRT or MB10. A secondary finding was categorically higher epilation in broad-beam arms compared with their minibeam dose counterparts. Conclusion: Our findings indicate trends that, despite the higher peak doses, proton minibeam therapy can reduce radiation side effects in shallow tissue and brain compared to proton broadbeam therapy. As the behavioral findings were mixed, confirmation studies are needed with larger numbers of animals. AAPM Research Seed Funding Grant.« less

Participation in High Energy Physics at the University of Chicago

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinec, Emil J.

2013-06-27

This report covers research at the University of Chicago in theoretical high energy physics and its connections to cosmology, over the period Nov. 1, 2009 to April 30, 2013. This research is divided broadly into two tasks: Task A, which covers a broad array of topics in high energy physics; and task C, primarily concerned with cosmology.

Experimental Demonstration of Adaptive Infrared Multispectral Imaging using Plasmonic Filter Array.

PubMed

Jang, Woo-Yong; Ku, Zahyun; Jeon, Jiyeon; Kim, Jun Oh; Lee, Sang Jun; Park, James; Noyola, Michael J; Urbas, Augustine

2016-10-10

In our previous theoretical study, we performed target detection using a plasmonic sensor array incorporating the data-processing technique termed "algorithmic spectrometry". We achieved the reconstruction of a target spectrum by extracting intensity at multiple wavelengths with high resolution from the image data obtained from the plasmonic array. The ultimate goal is to develop a full-scale focal plane array with a plasmonic opto-coupler in order to move towards the next generation of versatile infrared cameras. To this end, and as an intermediate step, this paper reports the experimental demonstration of adaptive multispectral imagery using fabricated plasmonic spectral filter arrays and proposed target detection scenarios. Each plasmonic filter was designed using periodic circular holes perforated through a gold layer, and an enhanced target detection strategy was proposed to refine the original spectrometry concept for spatial and spectral computation of the data measured from the plasmonic array. Both the spectrum of blackbody radiation and a metal ring object at multiple wavelengths were successfully reconstructed using the weighted superposition of plasmonic output images as specified in the proposed detection strategy. In addition, plasmonic filter arrays were theoretically tested on a target at extremely high temperature as a challenging scenario for the detection scheme.

Spatio-Temporal Equalizer for a Receiving-Antenna Feed Array

NASA Technical Reports Server (NTRS)

Mukai, Ryan; Lee, Dennis; Vilnrotter, Victor

2010-01-01

A spatio-temporal equalizer has been conceived as an improved means of suppressing multipath effects in the reception of aeronautical telemetry signals, and may be adaptable to radar and aeronautical communication applications as well. This equalizer would be an integral part of a system that would also include a seven-element planar array of receiving feed horns centered at the focal point of a paraboloidal antenna that would be nominally aimed at or near the aircraft that would be the source of the signal that one seeks to receive (see Figure 1). This spatio-temporal equalizer would consist mostly of a bank of seven adaptive finite-impulse-response (FIR) filters one for each element in the array - and the outputs of the filters would be summed (see Figure 2). The combination of the spatial diversity of the feedhorn array and the temporal diversity of the filter bank would afford better multipath-suppression performance than is achievable by means of temporal equalization alone. The seven-element feed array would supplant the single feed horn used in a conventional paraboloidal ground telemetry-receiving antenna. The radio-frequency telemetry signals re ceiv ed by the seven elements of the array would be digitized, converted to complex baseband form, and sent to the FIR filter bank, which would adapt itself in real time to enable reception of telemetry at a low bit error rate, even in the presence of multipath of the type found at many flight test ranges.

Employment of Adaptive Learning Techniques for the Discrimination of Acoustic Emissions.

DTIC Science & Technology

1983-11-01

Dereverberation Simulations ... ............ .. 96 Ŗ 4. ARRAY OPTIMIZATION ......... ...................... . 115 * 4.1 Phased Array Fundamentals... 115 4.2 Phased Array Diffraction Suboptimization ......... ... 121 , .i Page s 4.3 Diffraction Pattern Simulations of Phased Arrays...by differentiating (2.13.14) with respect to z and • -- equating equal powers of z , giving n-i c n bn + I/n kckbn-k (2.13.15)nk= This is very

High brightness photonic lantern kW-class amplifier

NASA Astrophysics Data System (ADS)

Montoya, Juan; Hwang, Chris; Aleshire, Chris; Reed, Patricia; Martz, Dale; Riley, Mike; Trainor, Michael; Belley, Catherine; Shaw, Scot; Fan, T. Y.; Ripin, Dan

2018-02-01

Pump-limited kW-class operation in a multimode fiber amplifier using adaptive mode control was achieved. A photonic lantern front end was used to inject an arbitrary superposition of modes on the input to a kW-class fiber amplifier to achieve a nearly diffraction-limited output. We report on the adaptive spatial mode control architecture which allows for compensating transverse-mode disturbances at high power. We also describe the advantages of adaptive spatial mode control for optical phased array systems. In particular, we show that the additional degrees of freedom allow for broader steering and improved atmospheric turbulence compensation relative to piston-only optical phased arrays.

A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

PubMed Central

Seo, Jiwon; Chen, Yu-Hsuan; De Lorenzo, David S.; Lo, Sherman; Enge, Per; Akos, Dennis; Lee, Jiyun

2011-01-01

Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities. PMID:22164116

A real-time capable software-defined receiver using GPU for adaptive anti-jam GPS sensors.

PubMed

Seo, Jiwon; Chen, Yu-Hsuan; De Lorenzo, David S; Lo, Sherman; Enge, Per; Akos, Dennis; Lee, Jiyun

2011-01-01

Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities.

Dynamic experiment design regularization approach to adaptive imaging with array radar/SAR sensor systems.

PubMed

Shkvarko, Yuriy; Tuxpan, José; Santos, Stewart

2011-01-01

We consider a problem of high-resolution array radar/SAR imaging formalized in terms of a nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) of the random wavefield scattered from a remotely sensed scene observed through a kernel signal formation operator and contaminated with random Gaussian noise. First, the Sobolev-type solution space is constructed to specify the class of consistent kernel SSP estimators with the reproducing kernel structures adapted to the metrics in such the solution space. Next, the "model-free" variational analysis (VA)-based image enhancement approach and the "model-based" descriptive experiment design (DEED) regularization paradigm are unified into a new dynamic experiment design (DYED) regularization framework. Application of the proposed DYED framework to the adaptive array radar/SAR imaging problem leads to a class of two-level (DEED-VA) regularized SSP reconstruction techniques that aggregate the kernel adaptive anisotropic windowing with the projections onto convex sets to enforce the consistency and robustness of the overall iterative SSP estimators. We also show how the proposed DYED regularization method may be considered as a generalization of the MVDR, APES and other high-resolution nonparametric adaptive radar sensing techniques. A family of the DYED-related algorithms is constructed and their effectiveness is finally illustrated via numerical simulations.

Effects of Adaptive Antenna Arrays on Broadband Signals.

DTIC Science & Technology

1980-06-01

dimensional array geometry. The signal impinging on the antenna array elements is assumed to have originated from a point source in the far field , or...tg9 (4) The assumptions used to identify the far field region of an array also lead to an approximation for ti(6) . It is ti (0 ) x i sin(e) (5) c...implementing the open form transfer function and coefficients of Eqs (16) 53 .. ... ... .. . . .. . . .. ... .. . ..... . .... . . .. through (21). For a

A Covariance Modeling Approach to Adaptive Beamforming and Detection

DTIC Science & Technology

1991-07-30

to achieve the main results of this report. I would especially like to thank Dr. E. J. Kelly for the support he has given me during the past years . His...direction of propagation A,, 0 S, Figure 4. Plane wace propagating through array. The array steering vector d(, E) is d~w d d2 ... dN]T (10) with...the covariance matrix to form a matched-filter beamformer that adapts to the interference environment. This was one of the first papers to propose using

Terrestrial adaptation of the thermal heliotrope.

NASA Technical Reports Server (NTRS)

Fairbanks, J. W.; Morse, F. H.

1971-01-01

The principle of using bimetal helical coils to cause solar arrays to track the sun in space is presently under consideration for array orientation on several spacecraft. Adaptation of this thermal heliotrope to terrestrial applications introduces additional design considerations. The dominance of solar-radiation energy input to the helical coil over convective energy losses has to be ensured, and wind effects must be minimized. As long as the cost of solar cells remains high, orientation will always result in a significant cost saving for the converter.

An adaptive array antenna for mobile satellite communications

NASA Technical Reports Server (NTRS)

Milne, Robert

1990-01-01

The design of an adaptive array antenna for land vehicle operation and its performance in an operational satellite system is described. Linear and circularly polarized antenna designs are presented. The acquisition and tracking operation of a satellite is described and the effect on the communications signal is discussed. A number of system requirements are examined that have a major impact on the antenna design. The results of environmental, power handling, and RFI testing are presented and potential problems are identified.

Adaption of the Magnetometer Towed Array geophysical system to meet Department of Energy needs for hazardous waste site characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, J.R.; McDonald, J.R.; Russell, R.J.

1995-10-01

This report documents US Department of Energy (DOE)-funded activities that have adapted the US Navy`s Surface Towed Ordnance Locator System (STOLS) to meet DOE needs for a ``... better, faster, safer and cheaper ...`` system for characterizing inactive hazardous waste sites. These activities were undertaken by Sandia National Laboratories (Sandia), the Naval Research Laboratory, Geo-Centers Inc., New Mexico State University and others under the title of the Magnetometer Towed Array (MTA).

Adaptive microlens array based on electrically charged polyvinyl chloride/dibutyl phthalate gel

NASA Astrophysics Data System (ADS)

Xu, Miao; Ren, Hongwen

2016-09-01

We prepared an adaptive microlens array (MLA) using a polyvinyl chloride/dibutyl phthalate gel and an indium-tin-oxide (ITO) glass substrate. The gel forms a membrane on the glass substrate and the ITO electrode has a ring array pattern. When the membrane is electrically charged by a DC voltage, the surface of the membrane above each circular electrode in the ring array can be deformed with a convex shape. As a result, the membrane functions as an MLA. By applying a voltage from 20 to ˜65 V to the electrode, the focal length of each microlens can be tuned from 300 to ˜160 μm. The dynamic response time can by reduced largely by changing the polarity of the DC voltage. Due to the advantages of optical isotropy, compact structure, and good stability, our MLA has potential applications in imaging, biometrics, and electronic displays.

Biomimetic multifunctional surfaces inspired from animals.

PubMed

Han, Zhiwu; Mu, Zhengzhi; Yin, Wei; Li, Wen; Niu, Shichao; Zhang, Junqiu; Ren, Luquan

2016-08-01

Over millions of years, animals have evolved to a higher intelligent level for their environment. A large number of diverse surface structures on their bodies have been formed to adapt to the extremely harsh environment. Just like the structural diversity existed in plants, the same also applies true in animals. Firstly, this article provides an overview and discussion of the most common functional surface structures inspired from animals, such as drag reduction, noise reduction, anti-adhesion, anti-wear, anti-erosion, anti-fog, water capture, and optical surfaces. Then, some typical characteristics of morphologies, structures, and materials of the animal multifunctional surfaces were discussed. The adaptation of these surfaces to environmental conditions was also analyzed. It mainly focuses on the relationship between their surface functions and their surface structural characteristics. Afterwards, the multifunctional mechanisms or principles of these surfaces were discussed. Models of these structures were provided for the development of structure materials and machinery surfaces. At last, fabrication techniques and existing or potential technical applications inspired from biomimetic multifunctional surfaces in animals were also discussed. The application prospects of the biomimetic functional surfaces are very broad, such as civil field of self-cleaning textile fabrics and non-stick pots, ocean field of oil-water separation, sports field of swimming suits, space development field of lens arrays. Copyright © 2016 Elsevier B.V. All rights reserved.

SNP-array reveals genome-wide patterns of geographical and potential adaptive divergence across the natural range of Atlantic salmon (Salmo salar).

PubMed

Bourret, Vincent; Kent, Matthew P; Primmer, Craig R; Vasemägi, Anti; Karlsson, Sten; Hindar, Kjetil; McGinnity, Philip; Verspoor, Eric; Bernatchez, Louis; Lien, Sigbjørn

2013-02-01

Atlantic salmon (Salmo salar) is one of the most extensively studied fish species in the world due to its significance in aquaculture, fisheries and ongoing conservation efforts to protect declining populations. Yet, limited genomic resources have hampered our understanding of genetic architecture in the species and the genetic basis of adaptation to the wide range of natural and artificial environments it occupies. In this study, we describe the development of a medium-density Atlantic salmon single nucleotide polymorphism (SNP) array based on expressed sequence tags (ESTs) and genomic sequencing. The array was used in the most extensive assessment of population genetic structure performed to date in this species. A total of 6176 informative SNPs were successfully genotyped in 38 anadromous and freshwater wild populations distributed across the species natural range. Principal component analysis clearly differentiated European and North American populations, and within Europe, three major regional genetic groups were identified for the first time in a single analysis. We assessed the potential for the array to disentangle neutral and putative adaptive divergence of SNP allele frequencies across populations and among regional groups. In Europe, secondary contact zones were identified between major clusters where endogenous and exogenous barriers could be associated, rendering the interpretation of environmental influence on potentially adaptive divergence equivocal. A small number of markers highly divergent in allele frequencies (outliers) were observed between (multiple) freshwater and anadromous populations, between northern and southern latitudes, and when comparing Baltic populations to all others. We also discuss the potential future applications of the SNP array for conservation, management and aquaculture. © 2012 Blackwell Publishing Ltd.

SAMICS marketing and distribution model

NASA Technical Reports Server (NTRS)

1978-01-01

A SAMICS (Solar Array Manufacturing Industry Costing Standards) was formulated as a computer simulation model. Given a proper description of the manufacturing technology as input, this model computes the manufacturing price of solar arrays for a broad range of production levels. This report presents a model for computing these marketing and distribution costs, the end point of the model being the loading dock of the final manufacturer.

Millimetre Level Accuracy GNSS Positioning with the Blind Adaptive Beamforming Method in Interference Environments.

PubMed

Daneshmand, Saeed; Marathe, Thyagaraja; Lachapelle, Gérard

2016-10-31

The use of antenna arrays in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its superior capability to suppress both narrowband and wideband interference. However, the phase distortions resulting from array processing may limit the applicability of these methods for high precision applications using carrier phase based positioning techniques. This paper studies the phase distortions occurring with the adaptive blind beamforming method in which satellite angle of arrival (AoA) information is not employed in the optimization problem. To cater to non-stationary interference scenarios, the array weights of the adaptive beamformer are continuously updated. The effects of these continuous updates on the tracking parameters of a GNSS receiver are analyzed. The second part of this paper focuses on reducing the phase distortions during the blind beamforming process in order to allow the receiver to perform carrier phase based positioning by applying a constraint on the structure of the array configuration and by compensating the array uncertainties. Limitations of the previous methods are studied and a new method is proposed that keeps the simplicity of the blind beamformer structure and, at the same time, reduces tracking degradations while achieving millimetre level positioning accuracy in interference environments. To verify the applicability of the proposed method and analyze the degradations, array signals corresponding to the GPS L1 band are generated using a combination of hardware and software simulators. Furthermore, the amount of degradation and performance of the proposed method under different conditions are evaluated based on Monte Carlo simulations.

Experimental Demonstration of Adaptive Infrared Multispectral Imaging using Plasmonic Filter Array

PubMed Central

Jang, Woo-Yong; Ku, Zahyun; Jeon, Jiyeon; Kim, Jun Oh; Lee, Sang Jun; Park, James; Noyola, Michael J.; Urbas, Augustine

2016-01-01

In our previous theoretical study, we performed target detection using a plasmonic sensor array incorporating the data-processing technique termed “algorithmic spectrometry”. We achieved the reconstruction of a target spectrum by extracting intensity at multiple wavelengths with high resolution from the image data obtained from the plasmonic array. The ultimate goal is to develop a full-scale focal plane array with a plasmonic opto-coupler in order to move towards the next generation of versatile infrared cameras. To this end, and as an intermediate step, this paper reports the experimental demonstration of adaptive multispectral imagery using fabricated plasmonic spectral filter arrays and proposed target detection scenarios. Each plasmonic filter was designed using periodic circular holes perforated through a gold layer, and an enhanced target detection strategy was proposed to refine the original spectrometry concept for spatial and spectral computation of the data measured from the plasmonic array. Both the spectrum of blackbody radiation and a metal ring object at multiple wavelengths were successfully reconstructed using the weighted superposition of plasmonic output images as specified in the proposed detection strategy. In addition, plasmonic filter arrays were theoretically tested on a target at extremely high temperature as a challenging scenario for the detection scheme. PMID:27721506

Adaptive antenna arrays for weak interfering signals

NASA Technical Reports Server (NTRS)

Gupta, I. J.

1985-01-01

The interference protection provided by adaptive antenna arrays to an Earth station or satellite receive antenna system is studied. The case where the interference is caused by the transmission from adjacent satellites or Earth stations whose signals inadverently enter the receiving system and interfere with the communication link is considered. Thus, the interfering signals are very weak. To increase the interference suppression, one can either decrease the thermal noise in the feedback loops or increase the gain of the auxiliary antennas in the interfering signal direction. Both methods are examined. It is shown that one may have to reduce the noise correlation to impractically low values and if directive auxiliary antennas are used, the auxiliary antenna size may have to be too large. One can, however, combine the two methods to achieve the specified interference suppression with reasonable requirements of noise decorrelation and auxiliary antenna size. Effects of the errors in the steering vector on the adaptive array performance are studied.

Adaptive Residual Interpolation for Color and Multispectral Image Demosaicking †

PubMed Central

Kiku, Daisuke; Okutomi, Masatoshi

2017-01-01

Color image demosaicking for the Bayer color filter array is an essential image processing operation for acquiring high-quality color images. Recently, residual interpolation (RI)-based algorithms have demonstrated superior demosaicking performance over conventional color difference interpolation-based algorithms. In this paper, we propose adaptive residual interpolation (ARI) that improves existing RI-based algorithms by adaptively combining two RI-based algorithms and selecting a suitable iteration number at each pixel. These are performed based on a unified criterion that evaluates the validity of an RI-based algorithm. Experimental comparisons using standard color image datasets demonstrate that ARI can improve existing RI-based algorithms by more than 0.6 dB in the color peak signal-to-noise ratio and can outperform state-of-the-art algorithms based on training images. We further extend ARI for a multispectral filter array, in which more than three spectral bands are arrayed, and demonstrate that ARI can achieve state-of-the-art performance also for the task of multispectral image demosaicking. PMID:29194407

Adaptive Residual Interpolation for Color and Multispectral Image Demosaicking.

PubMed

Monno, Yusuke; Kiku, Daisuke; Tanaka, Masayuki; Okutomi, Masatoshi

2017-12-01

Color image demosaicking for the Bayer color filter array is an essential image processing operation for acquiring high-quality color images. Recently, residual interpolation (RI)-based algorithms have demonstrated superior demosaicking performance over conventional color difference interpolation-based algorithms. In this paper, we propose adaptive residual interpolation (ARI) that improves existing RI-based algorithms by adaptively combining two RI-based algorithms and selecting a suitable iteration number at each pixel. These are performed based on a unified criterion that evaluates the validity of an RI-based algorithm. Experimental comparisons using standard color image datasets demonstrate that ARI can improve existing RI-based algorithms by more than 0.6 dB in the color peak signal-to-noise ratio and can outperform state-of-the-art algorithms based on training images. We further extend ARI for a multispectral filter array, in which more than three spectral bands are arrayed, and demonstrate that ARI can achieve state-of-the-art performance also for the task of multispectral image demosaicking.

Electrowetting lenses for compensating phase and curvature distortion in arrayed laser systems.

PubMed

Niederriter, Robert D; Watson, Alexander M; Zahreddine, Ramzi N; Cogswell, Carol J; Cormack, Robert H; Bright, Victor M; Gopinath, Juliet T

2013-05-10

We have demonstrated a one-dimensional array of individually addressable electrowetting tunable liquid lenses that compensate for more than one wave of phase distortion across a wavefront. We report a scheme for piston control using tunable liquid lens arrays in volume-bound cavities that alter the optical path length without affecting the wavefront curvature. Liquid lens arrays with separately tunable focus or phase control hold promise for laser communication systems and adaptive optics.

Piezo-Phototronic Enhanced UV Sensing Based on a Nanowire Photodetector Array.

PubMed

Han, Xun; Du, Weiming; Yu, Ruomeng; Pan, Caofeng; Wang, Zhong Lin

2015-12-22

A large array of Schottky UV photodetectors (PDs) based on vertical aligned ZnO nanowires is achieved. By introducing the piezo-phototronic effect, the performance of the PD array is enhanced up to seven times in photoreponsivity, six times in sensitivity, and 2.8 times in detection limit. The UV PD array may have applications in optoelectronic systems, adaptive optical computing, and communication. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparative study of absorption in tilted silicon nanowire arrays for photovoltaics

PubMed Central

2014-01-01

Silicon nanowire arrays have been shown to demonstrate light trapping properties and promising potential for next-generation photovoltaics. In this paper, we show that the absorption enhancement in vertical nanowire arrays on a perfectly electric conductor can be further improved through tilting. Vertical nanowire arrays have a 66.2% improvement in ultimate efficiency over an ideal double-pass thin film of the equivalent amount of material. Tilted nanowire arrays, with the same amount of material, exhibit improved performance over vertical nanowire arrays across a broad range of tilt angles (from 38° to 72°). The optimum tilt of 53° has an improvement of 8.6% over that of vertical nanowire arrays and 80.4% over that of the ideal double-pass thin film. Tilted nanowire arrays exhibit improved absorption over the solar spectrum compared with vertical nanowires since the tilt allows for the excitation of additional modes besides the HE 1m modes that are excited at normal incidence. We also observed that tilted nanowire arrays have improved performance over vertical nanowire arrays for a large range of incidence angles (under about 60°). PMID:25435833

Comparative study of absorption in tilted silicon nanowire arrays for photovoltaics.

PubMed

Kayes, Md Imrul; Leu, Paul W

2014-01-01

Silicon nanowire arrays have been shown to demonstrate light trapping properties and promising potential for next-generation photovoltaics. In this paper, we show that the absorption enhancement in vertical nanowire arrays on a perfectly electric conductor can be further improved through tilting. Vertical nanowire arrays have a 66.2% improvement in ultimate efficiency over an ideal double-pass thin film of the equivalent amount of material. Tilted nanowire arrays, with the same amount of material, exhibit improved performance over vertical nanowire arrays across a broad range of tilt angles (from 38° to 72°). The optimum tilt of 53° has an improvement of 8.6% over that of vertical nanowire arrays and 80.4% over that of the ideal double-pass thin film. Tilted nanowire arrays exhibit improved absorption over the solar spectrum compared with vertical nanowires since the tilt allows for the excitation of additional modes besides the HE 1m modes that are excited at normal incidence. We also observed that tilted nanowire arrays have improved performance over vertical nanowire arrays for a large range of incidence angles (under about 60°).

Adaptation of trees, forests and forestry to climate change

Treesearch

Daniel J. Chmura; Glenn T. Howe; Paul D. Anderson; Bradley J. St Clair

2010-01-01

Ongoing climate change will likely expose trees and forests to new stresses and disturbances during this century. Trees naturally adapt to changes in climate, but their natural adaptive ability may be compromised by the rapid changes projected for this century. In the broad sense, adaptation to climate change also includes the purposeful adaptation of human systems,...

Generation of dark hollow beam via coherent combination based on adaptive optics.

PubMed

Zheng, Yi; Wang, Xiaohua; Shen, Feng; Li, Xinyang

2010-12-20

A novel method for generating a dark hollow beam (DHB) is proposed and studied both theoretically and experimentally. A coherent combination technique for laser arrays is implemented based on adaptive optics (AO). A beam arraying structure and an active segmented mirror are designed and described. Piston errors are extracted by a zero-order interference detection system with the help of a custom-made photo-detectors array. An algorithm called the extremum approach is adopted to calculate feedback control signals. A dynamic piston error is imported by LiNbO₃ to test the capability of the AO servo. In a closed loop the stable and clear DHB is obtained. The experimental results confirm the feasibility of the concept.

An adaptive array antenna for mobile satellite communications

NASA Technical Reports Server (NTRS)

Milne, Robert

1988-01-01

The adaptive array is linearly polarized and consists essentially of a driven lambda/4 monopole surrounded by an array of parasitic elements all mounted on a ground plane of finite size. The parasitic elements are all connected to ground via pin diodes. By applying suitable bias voltages, the desired parasitic elements can be activated and made highly reflective. The directivity and pointing of the antenna beam can be controlled in both the azimuth and elevation planes using high speed digital switching techniques. The antenna RF losses are neglible and the maximum gain is close to the theoretical value determined by the effective aperture size. The antenna is compact, has a low profile, is inexpensive to manufacture and can handle high transmitter power.

Large Format Narrow-Band, Multi-Band, and Broad-Band LWIR QWIP Focal Planes for Space and Earth Science Applications

NASA Technical Reports Server (NTRS)

Gunapala, S. D.; Bandara, S. V.

2004-01-01

A 640x512 pixel, long-wavelength cutoff, narrow-band (delta(lambda)/approx. 10%) quantum well infrared photodetector (QWIP) focal plane array (FPA), a four-band QWIP FPA in the 4-16 m spectral region, and a broad-band (delta(lambda)/approx. 42%) QWIP FPA having 15.4 m cutoff have been demonstrated.

A Review of the Literature on Rural and Remote Pre-Service Teacher Preparation with a Focus on Blended and E-Learning Models

ERIC Educational Resources Information Center

Eaton, Sarah Elaine; Dressler, Roswita; Gereluk, Dianne

2015-01-01

Purpose: To review a broad array of current literature related to pre-service teacher education offered in blended and e-learning formats, with a focus on rural and remote teacher education. Results: The range of literature that we have surveyed is broad. We have consulted peer-reviewed academic journals, books, conference proceedings, government…

Ocean Observatories Initiative (OOI): Status of Design, Capabilities, and Implementation

NASA Astrophysics Data System (ADS)

Brasseur, L. H.; Banahan, S.; Cowles, T.

2009-05-01

The National Science Foundation's (NSF) Ocean Observatories Initiative (OOI) will implement the construction and operation of an interactive, integrated ocean observing network. This research- driven, multi-scale network will provide the broad ocean science community with access to advanced technology to enable studies of fundamental ocean processes. The OOI will afford observations at coastal, regional, and global scales on timeframes of milliseconds to decades in support of investigations into climate variability, ocean ecosystems, biogeochemical processes, coastal ocean dynamics, circulation and mixing dynamics, fluid-rock interactions, and the sub-seafloor biosphere. The elements of the OOI include arrays of fixed and re-locatable moorings, autonomous underwater vehicles, and cabled seafloor nodes. All assets combined, the OOI network will provide data from over 45 distinct types of sensors, comprising over 800 total sensors distributed in the Pacific and Atlantic oceans. These core sensors for the OOI were determined through a formal process of science requirements development. This core sensor array will be integrated through a system-wide cyberinfrastructure allowing for remote control of instruments, adaptive sampling, and near-real time access to data. Implementation of the network will stimulate new avenues of research and the development of new infrastructure, instrumentation, and sensor technologies. The OOI is funded by the NSF and managed by the Consortium for Ocean Leadership which focuses on the science, technology, education, and outreach for an emerging network of ocean observing systems.

New Developments in NOAA's Comprehensive Large Array-Data Stewardship System

NASA Astrophysics Data System (ADS)

Ritchey, N. A.; Morris, J. S.; Carter, D. J.

2012-12-01

The Comprehensive Large Array-data Stewardship System (CLASS) is part of the NOAA strategic goal of Climate Adaptation and Mitigation that gives focus to the building and sustaining of key observational assets and data archives critical to maintaining the global climate record. Since 2002, CLASS has been NOAA's enterprise solution for ingesting, storing and providing access to a host of near real-time remote sensing streams such as the Polar and Geostationary Operational Environmental Satellites (POES and GOES) and the Defense Meteorological Satellite Program (DMSP). Since October, 2011 CLASS has also been the dedicated Archive Data Segment (ADS) of the Suomi National Polar-orbiting Partnership (S-NPP). As the ADS, CLASS receives raw and processed S-NPP records for archival and distribution to the broad user community. Moving beyond just remote sensing and model data, NOAA has endorsed a plan to migrate all archive holdings from NOAA's National Data Centers into CLASS while retiring various disparate legacy data storage systems residing at the National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC) and the National Oceanographic Data Center (NODC). In parallel to this data migration, CLASS is evolving to a service-oriented architecture utilizing cloud technologies for dissemination in addition to clearly defined interfaces that allow better collaboration with partners. This evolution will require implementation of standard access protocols and metadata which will lead to cost effective data and information preservation.

Probing organic residues on Martian regolith simulants using a long-wave infrared Laser-induced breakdown spectroscopy linear array detection system

NASA Astrophysics Data System (ADS)

Prasad, Narasimha S.; Yang, Clayton S.-C.; Jin, Feng; Jia, Ken; Brown, EiEi; Hömmerich, Uwe; Jia, Yingqing; Trivedi, Sudhir; Wijewarnasuriya, Priyalal; Decuir, Eric; Samuels, Alan C.

2016-09-01

Recently, a mercury-cadmium-telluride (MCT) linear array detection system that is capable of rapidly capturing ( 1-5 second) a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the longwave infrarμed region (LWIR, 5.6 to 10 μm) has been developed. Similar to the conventional Ultraviolet (UV)-Visible (Vis) LIBS, a broad band emission spectrum of condensed phase samples covering the entire 5.6 to 10 μm region can be acquired from just a single laser-induced micro-plasma or averaging a few single laser-induced micro-plasmas. This setup has enabled probing samples "as is" without the need for extensive sample preparation and also offers the possibility of a simultaneous UV-Vis and LWIR LIBS measurement. A Martian regolith simulant (JSC Mars-1A) was studied with this novel Vis + LWIR LIBS array system. A broad SiO2 vibrational emission feature around 9.5 μm and multiple strong emission features between 6.5 to 8 μm can be clearly identified. The 6.5 to 8 μm features are possibly from biological impurities of the simulant. JSC Mars-1A samples with organic methyl salicylate (MeS, wintergreen oil) and Dimethyl methyl-phosphonate (DMMP) residues were also probed using the LWIR LIBS array system. Both molecular spectral signature around 6.5 μm and 9.5 μm of Martian regolith simulant and MeS and DMMP molecular signature emissions, such as Aromatic CC stretching band at 7.5 μm, C-CH3O asymmetric deformation at 7.6 μm, and P=O stretching band at 7.9 μm, are clearly observed from the LIBS emission spectra in the LWIR region.

Experimental instrumentation system for the Phased Array Mirror Extendible Large Aperture (PAMELA) test program

NASA Technical Reports Server (NTRS)

Boykin, William H., Jr.

1993-01-01

Adaptive optics are used in telescopes for both viewing objects with minimum distortion and for transmitting laser beams with minimum beam divergence and dance. In order to test concepts on a smaller scale, NASA MSFC is in the process of setting up an adaptive optics test facility with precision (fraction of wavelengths) measurement equipment. The initial system under test is the adaptive optical telescope called PAMELA (Phased Array Mirror Extendible Large Aperture). Goals of this test are: assessment of test hardware specifications for PAMELA application and the determination of the sensitivities of instruments for measuring PAMELA (and other adaptive optical telescopes) imperfections; evaluation of the PAMELA system integration effort and test progress and recommended actions to enhance these activities; and development of concepts and prototypes of experimental apparatuses for PAMELA.

Designing monitoring programs in an adaptive management context for regional multiple species conservation plans

USGS Publications Warehouse

Atkinson, A.J.; Trenham, P.C.; Fisher, R.N.; Hathaway, S.A.; Johnson, B.S.; Torres, S.G.; Moore, Y.C.

2004-01-01

critical management uncertainties; and 3) implementing long-term monitoring and adaptive management. Ultimately, the success of regional conservation planning depends on the ability of monitoring programs to confront the challenges of adaptively managing and monitoring complex ecosystems and diverse arrays of sensitive species.

Study on Interference Suppression Algorithms for Electronic Noses: A Review

PubMed Central

Liang, Zhifang; Zhang, Ci; Sun, Hao; Liu, Tao

2018-01-01

Electronic noses (e-nose) are composed of an appropriate pattern recognition system and a gas sensor array with a certain degree of specificity and broad spectrum characteristics. The gas sensors have their own shortcomings of being highly sensitive to interferences which has an impact on the detection of target gases. When there are interferences, the performance of the e-nose will deteriorate. Therefore, it is urgent to study interference suppression techniques for e-noses. This paper summarizes the sources of interferences and reviews the advances made in recent years in interference suppression for e-noses. According to the factors which cause interference, interferences can be classified into two types: interference caused by changes of operating conditions and interference caused by hardware failures. The existing suppression methods were summarized and analyzed from these two aspects. Since the interferences of e-noses are uncertain and unstable, it can be found that some nonlinear methods have good effects for interference suppression, such as methods based on transfer learning, adaptive methods, etc. PMID:29649152

Courting disaster: How diversification rate affects fitness under risk

PubMed Central

Ratcliff, William C; Hawthorne, Peter; Libby, Eric

2015-01-01

Life is full of risk. To deal with this uncertainty, many organisms have evolved bet-hedging strategies that spread risk through phenotypic diversification. These rates of diversification can vary by orders of magnitude in different species. Here we examine how key characteristics of risk and organismal ecology affect the fitness consequences of variation in diversification rate. We find that rapid diversification is strongly favored when the risk faced has a wide spatial extent, with a single disaster affecting a large fraction of the population. This advantage is especially great in small populations subject to frequent disaster. In contrast, when risk is correlated through time, slow diversification is favored because it allows adaptive tracking of disasters that tend to occur in series. Naturally evolved diversification mechanisms in diverse organisms facing a broad array of environmental risks largely support these results. The theory presented in this article provides a testable ecological hypothesis to explain the prevalence of slow stochastic switching among microbes and rapid, within-clutch diversification strategies among plants and animals. PMID:25410817

Compliant tactile sensor for generating a signal related to an applied force

NASA Technical Reports Server (NTRS)

Torres-Jara, Eduardo (Inventor)

2012-01-01

Tactile sensor. The sensor includes a compliant convex surface disposed above a sensor array, the sensor array adapted to respond to deformation of the convex surface to generate a signal related to an applied force vector.

The Diversity of REcent and Ancient huMan (DREAM): A New Microarray for Genetic Anthropology and Genealogy, Forensics, and Personalized Medicine.

PubMed

Elhaik, Eran; Yusuf, Leeban; Anderson, Ainan I J; Pirooznia, Mehdi; Arnellos, Dimitrios; Vilshansky, Gregory; Ercal, Gunes; Lu, Yontao; Webster, Teresa; Baird, Michael L; Esposito, Umberto

2017-12-01

The human population displays wide variety in demographic history, ancestry, content of DNA derived from hominins or ancient populations, adaptation, traits, copy number variation, drug response, and more. These polymorphisms are of broad interest to population geneticists, forensics investigators, and medical professionals. Historically, much of that knowledge was gained from population survey projects. Although many commercial arrays exist for genome-wide single-nucleotide polymorphism genotyping, their design specifications are limited and they do not allow a full exploration of biodiversity. We thereby aimed to design the Diversity of REcent and Ancient huMan (DREAM)-an all-inclusive microarray that would allow both identification of known associations and exploration of standing questions in genetic anthropology, forensics, and personalized medicine. DREAM includes probes to interrogate ancestry informative markers obtained from over 450 human populations, over 200 ancient genomes, and 10 archaic hominins. DREAM can identify 94% and 61% of all known Y and mitochondrial haplogroups, respectively, and was vetted to avoid interrogation of clinically relevant markers. To demonstrate its capabilities, we compared its FST distributions with those of the 1000 Genomes Project and commercial arrays. Although all arrays yielded similarly shaped (inverse J) FST distributions, DREAM's autosomal and X-chromosomal distributions had the highest mean FST, attesting to its ability to discern subpopulations. DREAM performances are further illustrated in biogeographical, identical by descent, and copy number variation analyses. In summary, with approximately 800,000 markers spanning nearly 2,000 genes, DREAM is a useful tool for genetic anthropology, forensic, and personalized medicine studies. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Adaptive Jacobian Fuzzy Attitude Control for Flexible Spacecraft Combined Attitude and Sun Tracking System

NASA Astrophysics Data System (ADS)

Chak, Yew-Chung; Varatharajoo, Renuganth

2016-07-01

Many spacecraft attitude control systems today use reaction wheels to deliver precise torques to achieve three-axis attitude stabilization. However, irrecoverable mechanical failure of reaction wheels could potentially lead to mission interruption or total loss. The electrically-powered Solar Array Drive Assemblies (SADA) are usually installed in the pitch axis which rotate the solar arrays to track the Sun, can produce torques to compensate for the pitch-axis wheel failure. In addition, the attitude control of a flexible spacecraft poses a difficult problem. These difficulties include the strong nonlinear coupled dynamics between the rigid hub and flexible solar arrays, and the imprecisely known system parameters, such as inertia matrix, damping ratios, and flexible mode frequencies. In order to overcome these drawbacks, the adaptive Jacobian tracking fuzzy control is proposed for the combined attitude and sun-tracking control problem of a flexible spacecraft during attitude maneuvers in this work. For the adaptation of kinematic and dynamic uncertainties, the proposed scheme uses an adaptive sliding vector based on estimated attitude velocity via approximate Jacobian matrix. The unknown nonlinearities are approximated by deriving the fuzzy models with a set of linguistic If-Then rules using the idea of sector nonlinearity and local approximation in fuzzy partition spaces. The uncertain parameters of the estimated nonlinearities and the Jacobian matrix are being adjusted online by an adaptive law to realize feedback control. The attitude of the spacecraft can be directly controlled with the Jacobian feedback control when the attitude pointing trajectory is designed with respect to the spacecraft coordinate frame itself. A significant feature of this work is that the proposed adaptive Jacobian tracking scheme will result in not only the convergence of angular position and angular velocity tracking errors, but also the convergence of estimated angular velocity to the actual angular velocity. Numerical results are presented to demonstrate the effectiveness of the proposed scheme in tracking the desired attitude, as well as suppressing the elastic deflection effects of solar arrays during maneuver.

Development of a Facility for Combustion Stability Experiments at Supercritical Pressure

DTIC Science & Technology

2013-12-01

by the exhaust orifice. This technique adds freedom for designing a large array experimental conditions, because chamber pressure is controlled...analytical examination reveals a broad array of frequencies. The analytical relationship between chamber length L, acoustic frequency fF, and the speed...the pressure amplitude is directly controlled by altering the voltage input to the sirens, similar to a traditional loudspeaker . Last, both a PN and

Comparisons between mammalian and artificial olfaction based on arrays of carbon black-polymer composite vapor detectors.

PubMed

Lewis, Nathan S

2004-09-01

Arrays of broadly cross-reactive vapor sensors provide a man-made implementation of an olfactory system, in which an analyte elicits a response from many receptors and each receptor responds to a variety of analytes. Pattern recognition methods are then used to detect analytes based on the collective response of the sensor array. With the use of this architecture, arrays of chemically sensitive resistors made from composites of conductors and insulating organic polymers have been shown to robustly classify, identify, and quantify a diverse collection of organic vapors, even though no individual sensor responds selectively to a particular analyte. The properties and functioning of these arrays are inspired by advances in the understanding of biological olfaction, and in turn, evaluation of the performance of the man-made array provides suggestions regarding some of the fundamental odor detection principles of the mammalian olfactory system.

Enhancing the spectral response of filled bolometer arrays for submillimeter astronomy.

PubMed

Revéret, Vincent; Rodriguez, Louis; Agnèse, Patrick

2010-12-10

Future missions for astrophysical studies in the submillimeter region will need detectors with very high sensitivity and large fields of view. Bolometer arrays can fulfill these requirements over a very broad band. We describe a technique that enables bolometer arrays that use quarter-wave cavities to have a high spectral response over most of the submillimeter band. This technique is based on the addition on the front of the array of an antireflecting dielectric layer. The optimum parameters (layer thickness and distance to the array) are determined by a 2D analytic code. This general principle is applied to the case of Herschel PACS bolometers (optimized for the 60 to 210 μm band). As an example, we demonstrate experimentally that a PACS array covered by a 138 μm thick silicon layer can improve the spectral response by a factor of 1.7 in the 450 μm band.

Dynamic Experiment Design Regularization Approach to Adaptive Imaging with Array Radar/SAR Sensor Systems

PubMed Central

Shkvarko, Yuriy; Tuxpan, José; Santos, Stewart

2011-01-01

We consider a problem of high-resolution array radar/SAR imaging formalized in terms of a nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) of the random wavefield scattered from a remotely sensed scene observed through a kernel signal formation operator and contaminated with random Gaussian noise. First, the Sobolev-type solution space is constructed to specify the class of consistent kernel SSP estimators with the reproducing kernel structures adapted to the metrics in such the solution space. Next, the “model-free” variational analysis (VA)-based image enhancement approach and the “model-based” descriptive experiment design (DEED) regularization paradigm are unified into a new dynamic experiment design (DYED) regularization framework. Application of the proposed DYED framework to the adaptive array radar/SAR imaging problem leads to a class of two-level (DEED-VA) regularized SSP reconstruction techniques that aggregate the kernel adaptive anisotropic windowing with the projections onto convex sets to enforce the consistency and robustness of the overall iterative SSP estimators. We also show how the proposed DYED regularization method may be considered as a generalization of the MVDR, APES and other high-resolution nonparametric adaptive radar sensing techniques. A family of the DYED-related algorithms is constructed and their effectiveness is finally illustrated via numerical simulations. PMID:22163859

Local motion adaptation enhances the representation of spatial structure at EMD arrays

PubMed Central

Lindemann, Jens P.; Egelhaaf, Martin

2017-01-01

Neuronal representation and extraction of spatial information are essential for behavioral control. For flying insects, a plausible way to gain spatial information is to exploit distance-dependent optic flow that is generated during translational self-motion. Optic flow is computed by arrays of local motion detectors retinotopically arranged in the second neuropile layer of the insect visual system. These motion detectors have adaptive response characteristics, i.e. their responses to motion with a constant or only slowly changing velocity decrease, while their sensitivity to rapid velocity changes is maintained or even increases. We analyzed by a modeling approach how motion adaptation affects signal representation at the output of arrays of motion detectors during simulated flight in artificial and natural 3D environments. We focused on translational flight, because spatial information is only contained in the optic flow induced by translational locomotion. Indeed, flies, bees and other insects segregate their flight into relatively long intersaccadic translational flight sections interspersed with brief and rapid saccadic turns, presumably to maximize periods of translation (80% of the flight). With a novel adaptive model of the insect visual motion pathway we could show that the motion detector responses to background structures of cluttered environments are largely attenuated as a consequence of motion adaptation, while responses to foreground objects stay constant or even increase. This conclusion even holds under the dynamic flight conditions of insects. PMID:29281631

78 FR 14233 - Electronic Retirement Processing

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-05

.... Public/private key (asymmetric) cryptography is a method of creating a unique mark, known as a digital... delivering a broad array of administrative services to multiple agencies. Shared symmetric key cryptography...

A powerful tool for genome analysis in maize: development and evaluation of the high density 600 k SNP genotyping array.

PubMed

Unterseer, Sandra; Bauer, Eva; Haberer, Georg; Seidel, Michael; Knaak, Carsten; Ouzunova, Milena; Meitinger, Thomas; Strom, Tim M; Fries, Ruedi; Pausch, Hubert; Bertani, Christofer; Davassi, Alessandro; Mayer, Klaus Fx; Schön, Chris-Carolin

2014-09-29

High density genotyping data are indispensable for genomic analyses of complex traits in animal and crop species. Maize is one of the most important crop plants worldwide, however a high density SNP genotyping array for analysis of its large and highly dynamic genome was not available so far. We developed a high density maize SNP array composed of 616,201 variants (SNPs and small indels). Initially, 57 M variants were discovered by sequencing 30 representative temperate maize lines and then stringently filtered for sequence quality scores and predicted conversion performance on the array resulting in the selection of 1.2 M polymorphic variants assayed on two screening arrays. To identify high-confidence variants, 285 DNA samples from a broad genetic diversity panel of worldwide maize lines including the samples used for sequencing, important founder lines for European maize breeding, hybrids, and proprietary samples with European, US, semi-tropical, and tropical origin were used for experimental validation. We selected 616 k variants according to their performance during validation, support of genotype calls through sequencing data, and physical distribution for further analysis and for the design of the commercially available Affymetrix® Axiom® Maize Genotyping Array. This array is composed of 609,442 SNPs and 6,759 indels. Among these are 116,224 variants in coding regions and 45,655 SNPs of the Illumina® MaizeSNP50 BeadChip for study comparison. In a subset of 45,974 variants, apart from the target SNP additional off-target variants are detected, which show only a minor bias towards intermediate allele frequencies. We performed principal coordinate and admixture analyses to determine the ability of the array to detect and resolve population structure and investigated the extent of LD within a worldwide validation panel. The high density Affymetrix® Axiom® Maize Genotyping Array is optimized for European and American temperate maize and was developed based on a diverse sample panel by applying stringent quality filter criteria to ensure its suitability for a broad range of applications. With 600 k variants it is the largest currently publically available genotyping array in crop species.

Anatomical features of pepper plants (Capsicum annuum L.) grown under red light-emitting diodes supplemented with blue or far-red light

NASA Technical Reports Server (NTRS)

Schuerger, A. C.; Brown, C. S.; Stryjewski, E. C.

1997-01-01

Pepper plants (Capsicum annuum L. cv., Hungarian Wax) were grown under metal halide (MH) lamps or light-emitting diode (LED) arrays with different spectra to determine the effects of light quality on plant anatomy of leaves and stems. One LED (660) array supplied 90% red light at 660 nm (25nm band-width at half-peak height) and 1% far-red light between 700-800nm. A second LED (660/735) array supplied 83% red light at 660nm and 17% far-red light at 735nm (25nm band-width at half-peak height). A third LED (660/blue) array supplied 98% red light at 660nm, 1% blue light between 350-550nm, and 1% far-red light between 700-800nm. Control plants were grown under broad spectrum metal halide lamps. Plants were gron at a mean photon flux (300-800nm) of 330 micromol m-2 s-1 under a 12 h day-night photoperiod. Significant anatomical changes in stem and leaf morphologies were observed in plants grown under the LED arrays compared to plants grown under the broad-spectrum MH lamp. Cross-sectional areas of pepper stems, thickness of secondary xylem, numbers of intraxylary phloem bundles in the periphery of stem pith tissues, leaf thickness, numbers of choloplasts per palisade mesophyll cell, and thickness of palisade and spongy mesophyll tissues were greatest in peppers grown under MH lamps, intermediate in plants grown under the 660/blue LED array, and lowest in peppers grown under the 660 or 660/735 LED arrays. Most anatomical features of pepper stems and leaves were similar among plants grown under 660 or 660/735 LED arrays. The effects of spectral quality on anatomical changes in stem and leaf tissues of peppers generally correlate to the amount of blue light present in the primary light source.

Anatomical features of pepper plants (Capsicum annuum L.) grown under red light-emitting diodes supplemented with blue or far-red light.

PubMed

Schuerger, A C; Brown, C S; Stryjewski, E C

1997-03-01

Pepper plants (Capsicum annuum L. cv., Hungarian Wax) were grown under metal halide (MH) lamps or light-emitting diode (LED) arrays with different spectra to determine the effects of light quality on plant anatomy of leaves and stems. One LED (660) array supplied 90% red light at 660 nm (25nm band-width at half-peak height) and 1% far-red light between 700-800nm. A second LED (660/735) array supplied 83% red light at 660nm and 17% far-red light at 735nm (25nm band-width at half-peak height). A third LED (660/blue) array supplied 98% red light at 660nm, 1% blue light between 350-550nm, and 1% far-red light between 700-800nm. Control plants were grown under broad spectrum metal halide lamps. Plants were gron at a mean photon flux (300-800nm) of 330 micromol m-2 s-1 under a 12 h day-night photoperiod. Significant anatomical changes in stem and leaf morphologies were observed in plants grown under the LED arrays compared to plants grown under the broad-spectrum MH lamp. Cross-sectional areas of pepper stems, thickness of secondary xylem, numbers of intraxylary phloem bundles in the periphery of stem pith tissues, leaf thickness, numbers of choloplasts per palisade mesophyll cell, and thickness of palisade and spongy mesophyll tissues were greatest in peppers grown under MH lamps, intermediate in plants grown under the 660/blue LED array, and lowest in peppers grown under the 660 or 660/735 LED arrays. Most anatomical features of pepper stems and leaves were similar among plants grown under 660 or 660/735 LED arrays. The effects of spectral quality on anatomical changes in stem and leaf tissues of peppers generally correlate to the amount of blue light present in the primary light source.

Integrated Reconfigurable Aperture, Digital Beam Forming, and Software GPS Receiver for UAV Navigation

DTIC Science & Technology

2007-12-11

Implemented both carrier and code phase tracking loop for performance evaluation of a minimum power beam forming algorithm and null steering algorithm...4 Antennal Antenna2 Antenna K RF RF RF ct, Ct~2 ChKx1 X2 ....... Xk A W ~ ~ =Z, x W ,=1 Fig. 5. Schematics of a K-element antenna array spatial...adaptive processor Antennal Antenna K A N-i V/ ( Vil= .i= VK Fig. 6. Schematics of a K-element antenna array space-time adaptive processor Two additional

A Four-Phase Modulation System for Use with an Adaptive Array.

DTIC Science & Technology

1982-07-01

MODULATION SYSTEM FORIteia epr * ~USE WITH AN ADAPTIVE ARRAY *P RIGOG EOTM~E _____________________________________ ESL 711679-5 7s AUTHOeO~) 9 . CONTRACT r0...OUSOLE1T6 UNCLASSIFIED SECURITY CLASSIFICATION OF THIS P040E (when Doe I91 r2 UNCLASSIFIED 8ncumV CL"M,ICAnIo, o TP , ImS 8... ., 9 fte-H - LMS...nterval has a duration of : Tb seconds. a(t) is a pseudonotse code, i.e., a maximum length " lInear shift register sequence [ 9 ]. The code symbol interval

Adaptive antenna arrays for satellite communication

NASA Technical Reports Server (NTRS)

Gupta, Inder J.

1989-01-01

The feasibility of using adaptive antenna arrays to provide interference protection in satellite communications was studied. The feedback loops as well as the sample matric inversion (SMI) algorithm for weight control were studied. Appropriate modifications in the two were made to achieve the required interference suppression. An experimental system was built to test the modified feedback loops and the modified SMI algorithm. The performance of the experimental system was evaluated using bench generated signals and signals received from TVRO geosynchronous satellites. A summary of results is given. Some suggestions for future work are also presented.

Cold plasma decontamination using flexible jet arrays

NASA Astrophysics Data System (ADS)

Konesky, Gregory

2010-04-01

Arrays of atmospheric discharge cold plasma jets have been used to decontaminate surfaces of a wide range of microorganisms quickly, yet not damage that surface. Its effectiveness in decomposing simulated chemical warfare agents has also been demonstrated, and may also find use in assisting in the cleanup of radiological weapons. Large area jet arrays, with short dwell times, are necessary for practical applications. Realistic situations will also require jet arrays that are flexible to adapt to contoured or irregular surfaces. Various large area jet array prototypes, both planar and flexible, are described, as is the application to atmospheric decontamination.

Study of a MEMS-based Shack-Hartmann wavefront sensor with adjustable pupil sampling for astronomical adaptive optics.

PubMed

Baranec, Christoph; Dekany, Richard

2008-10-01

We introduce a Shack-Hartmann wavefront sensor for adaptive optics that enables dynamic control of the spatial sampling of an incoming wavefront using a segmented mirror microelectrical mechanical systems (MEMS) device. Unlike a conventional lenslet array, subapertures are defined by either segments or groups of segments of a mirror array, with the ability to change spatial pupil sampling arbitrarily by redefining the segment grouping. Control over the spatial sampling of the wavefront allows for the minimization of wavefront reconstruction error for different intensities of guide source and different atmospheric conditions, which in turn maximizes an adaptive optics system's delivered Strehl ratio. Requirements for the MEMS devices needed in this Shack-Hartmann wavefront sensor are also presented.

Adaptive optics for array telescopes using piston-and-tilt wave-front sensing

NASA Technical Reports Server (NTRS)

Wizinowich, P.; Mcleod, B.; Lloyd-Yhart, M.; Angel, J. R. P.; Colucci, D.; Dekany, R.; Mccarthy, D.; Wittman, D.; Scott-Fleming, I.

1992-01-01

A near-infrared adaptive optics system operating at about 50 Hz has been used to control phase errors adaptively between two mirrors of the Multiple Mirror Telescope by stabilizing the position of the interference fringe in the combined unresolved far-field image. The resultant integrated images have angular resolutions of better than 0.1 arcsec and fringe contrasts of more than 0.6. Measurements of wave-front tilt have confirmed the wavelength independence of image motion. These results show that interferometric sensing of phase errors, when combined with a system for sensing the wave-front tilt of the individual telescopes, will provide a means of achieving a stable diffraction-limited focus with segmented telescopes or arrays of telescopes.

Tissue matrix arrays for high throughput screening and systems analysis of cell function

PubMed Central

Beachley, Vince Z.; Wolf, Matthew T.; Sadtler, Kaitlyn; Manda, Srikanth S.; Jacobs, Heather; Blatchley, Michael; Bader, Joel S.; Pandey, Akhilesh; Pardoll, Drew; Elisseeff, Jennifer H.

2015-01-01

Cell and protein arrays have demonstrated remarkable utility in the high-throughput evaluation of biological responses; however, they lack the complexity of native tissue and organs. Here, we describe tissue extracellular matrix (ECM) arrays for screening biological outputs and systems analysis. We spotted processed tissue ECM particles as two-dimensional arrays or incorporated them with cells to generate three-dimensional cell-matrix microtissue arrays. We then investigated the response of human stem, cancer, and immune cells to tissue ECM arrays originating from 11 different tissues, and validated the 2D and 3D arrays as representative of the in vivo microenvironment through quantitative analysis of tissue-specific cellular responses, including matrix production, adhesion and proliferation, and morphological changes following culture. The biological outputs correlated with tissue proteomics, and network analysis identified several proteins linked to cell function. Our methodology enables broad screening of ECMs to connect tissue-specific composition with biological activity, providing a new resource for biomaterials research and translation. PMID:26480475

A Readout Integrated Circuit (ROIC) employing self-adaptive background current compensation technique for Infrared Focal Plane Array (IRFPA)

NASA Astrophysics Data System (ADS)

Zhou, Tong; Zhao, Jian; He, Yong; Jiang, Bo; Su, Yan

2018-05-01

A novel self-adaptive background current compensation circuit applied to infrared focal plane array is proposed in this paper, which can compensate the background current generated in different conditions. Designed double-threshold detection strategy is to estimate and eliminate the background currents, which could significantly reduce the hardware overhead and improve the uniformity among different pixels. In addition, the circuit is well compatible to various categories of infrared thermo-sensitive materials. The testing results of a 4 × 4 experimental chip showed that the proposed circuit achieves high precision, wide application and high intelligence. Tape-out of the 320 × 240 readout circuit, as well as the bonding, encapsulation and imaging verification of uncooled infrared focal plane array, have also been completed.

Digital equalization of time-delay array receivers on coherent laser communications.

PubMed

Belmonte, Aniceto

2017-01-15

Field conjugation arrays use adaptive combining techniques on multi-aperture receivers to improve the performance of coherent laser communication links by mitigating the consequences of atmospheric turbulence on the down-converted coherent power. However, this motivates the use of complex receivers as optical signals collected by different apertures need to be adaptively processed, co-phased, and scaled before they are combined. Here, we show that multiple apertures, coupled with optical delay lines, combine retarded versions of a signal at a single coherent receiver, which uses digital equalization to obtain diversity gain against atmospheric fading. We found in our analysis that, instead of field conjugation arrays, digital equalization of time-delay multi-aperture receivers is a simpler and more versatile approach to accomplish reduction of atmospheric fading.

Use of artificial intelligence in the design of small peptide antibiotics effective against a broad spectrum of highly antibiotic-resistant superbugs.

PubMed

Cherkasov, Artem; Hilpert, Kai; Jenssen, Håvard; Fjell, Christopher D; Waldbrook, Matt; Mullaly, Sarah C; Volkmer, Rudolf; Hancock, Robert E W

2009-01-16

Increased multiple antibiotic resistance in the face of declining antibiotic discovery is one of society's most pressing health issues. Antimicrobial peptides represent a promising new class of antibiotics. Here we ask whether it is possible to make small broad spectrum peptides employing minimal assumptions, by capitalizing on accumulating chemical biology information. Using peptide array technology, two large random 9-amino-acid peptide libraries were iteratively created using the amino acid composition of the most active peptides. The resultant data was used together with Artificial Neural Networks, a powerful machine learning technique, to create quantitative in silico models of antibiotic activity. On the basis of random testing, these models proved remarkably effective in predicting the activity of 100,000 virtual peptides. The best peptides, representing the top quartile of predicted activities, were effective against a broad array of multidrug-resistant "Superbugs" with activities that were equal to or better than four highly used conventional antibiotics, more effective than the most advanced clinical candidate antimicrobial peptide, and protective against Staphylococcus aureus infections in animal models.

Networked Airborne Communications Using Adaptive Multi Beam Directional Links

DTIC Science & Technology

2016-03-05

Networked Airborne Communications Using Adaptive Multi-Beam Directional Links R. Bruce MacLeod Member, IEEE, and Adam Margetts Member, IEEE MIT...provide new techniques for increasing throughput in airborne adaptive directional net- works. By adaptive directional linking, we mean systems that can...techniques can dramatically increase the capacity in airborne networks. Advances in digital array technology are beginning to put these gains within reach

Study of LEO-SAT microwave link for broad-band mobile satellite communication system

NASA Technical Reports Server (NTRS)

Fujise, Masayuki; Chujo, Wataru; Chiba, Isamu; Furuhama, Yoji; Kawabata, Kazuaki; Konishi, Yoshihiko

1993-01-01

In the field of mobile satellite communications, a system based on low-earth-orbit satellites (LEO-SAT's) such as the Iridium system has been proposed. The LEO-SAT system is able to offer mobile telecommunication services in high-latitude areas. Rain degradation, fading and shadowing are also expected to be decreased when the system is operated at a high elevation angle. Furthermore, the propagation delay generated in the LEO-SAT system is less pronounced than that in the geostationary orbit satellite (GEO-SAT) system and, in voice services, the effect of the delay is almost negligible. We proposed a concept of a broad-band mobile satellite communication system with LEO-SAT's and Optical ISL. In that system, a fixed L-band (1.6/1.5 GHz) multibeam is used to offer narrow band service to the mobile terminals in the entire area covered by a LEO-SAT and steerable Ka-band (30/20 GHz) spot beams are used for the wide band service. In this paper, we present results of a study of LEO-SAT microwave link between a satellite and a mobile terminal for a broad-band mobile satellite communication system. First, the results of link budget calculations are presented and the antennas mounted on satellites are shown. For a future mobile antenna technology, we also show digital beamforming (DBF) techniques. DBF, together with modulation and/or demodulation, is becoming a key technique for mobile antennas with advanced functions such as antenna pattern calibration, correction, and radio interference suppression. In this paper, efficient DBF techniques for transmitting and receiving are presented. Furthermore, an adaptive array antenna system suitable for this LEO-SAT is presented.

What is adaptive about adaptive decision making? A parallel constraint satisfaction account.

PubMed

Glöckner, Andreas; Hilbig, Benjamin E; Jekel, Marc

2014-12-01

There is broad consensus that human cognition is adaptive. However, the vital question of how exactly this adaptivity is achieved has remained largely open. Herein, we contrast two frameworks which account for adaptive decision making, namely broad and general single-mechanism accounts vs. multi-strategy accounts. We propose and fully specify a single-mechanism model for decision making based on parallel constraint satisfaction processes (PCS-DM) and contrast it theoretically and empirically against a multi-strategy account. To achieve sufficiently sensitive tests, we rely on a multiple-measure methodology including choice, reaction time, and confidence data as well as eye-tracking. Results show that manipulating the environmental structure produces clear adaptive shifts in choice patterns - as both frameworks would predict. However, results on the process level (reaction time, confidence), in information acquisition (eye-tracking), and from cross-predicting choice consistently corroborate single-mechanisms accounts in general, and the proposed parallel constraint satisfaction model for decision making in particular. Copyright © 2014 Elsevier B.V. All rights reserved.

A Background Noise Reduction Technique Using Adaptive Noise Cancellation for Microphone Arrays

NASA Technical Reports Server (NTRS)

Spalt, Taylor B.; Fuller, Christopher R.; Brooks, Thomas F.; Humphreys, William M., Jr.; Brooks, Thomas F.

2011-01-01

Background noise in wind tunnel environments poses a challenge to acoustic measurements due to possible low or negative Signal to Noise Ratios (SNRs) present in the testing environment. This paper overviews the application of time domain Adaptive Noise Cancellation (ANC) to microphone array signals with an intended application of background noise reduction in wind tunnels. An experiment was conducted to simulate background noise from a wind tunnel circuit measured by an out-of-flow microphone array in the tunnel test section. A reference microphone was used to acquire a background noise signal which interfered with the desired primary noise source signal at the array. The technique s efficacy was investigated using frequency spectra from the array microphones, array beamforming of the point source region, and subsequent deconvolution using the Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS) algorithm. Comparisons were made with the conventional techniques for improving SNR of spectral and Cross-Spectral Matrix subtraction. The method was seen to recover the primary signal level in SNRs as low as -29 dB and outperform the conventional methods. A second processing approach using the center array microphone as the noise reference was investigated for more general applicability of the ANC technique. It outperformed the conventional methods at the -29 dB SNR but yielded less accurate results when coherence over the array dropped. This approach could possibly improve conventional testing methodology but must be investigated further under more realistic testing conditions.

The mechanism of color change in the neon tetra fish: a light-induced tunable photonic crystal array.

PubMed

Gur, Dvir; Palmer, Benjamin A; Leshem, Ben; Oron, Dan; Fratzl, Peter; Weiner, Steve; Addadi, Lia

2015-10-12

The fresh water fish neon tetra has the ability to change the structural color of its lateral stripe in response to a change in the light conditions, from blue-green in the light-adapted state to indigo in the dark-adapted state. The colors are produced by constructive interference of light reflected from stacks of intracellular guanine crystals, forming tunable photonic crystal arrays. We have used micro X-ray diffraction to track in time distinct diffraction spots corresponding to individual crystal arrays within a single cell during the color change. We demonstrate that reversible variations in crystal tilt within individual arrays are responsible for the light-induced color variations. These results settle a long-standing debate between the two proposed models, the "Venetian blinds" model and the "accordion" model. The insight gained from this biogenic light-induced photonic tunable system may provide inspiration for the design of artificial optical tunable systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coherent beam combining of collimated fiber array based on target-in-the-loop technique

NASA Astrophysics Data System (ADS)

Li, Xinyang; Geng, Chao; Zhang, Xiaojun; Rao, Changhui

2011-11-01

Coherent beam combining (CBC) of fiber array is a promising way to generate high power and high quality laser beams. Target-in-the-loop (TIL) technique might be an effective way to ensure atmosphere propagation compensation without wavefront sensors. In this paper, we present very recent research work about CBC of collimated fiber array using TIL technique at the Key Lab on Adaptive Optics (KLAO), CAS. A novel Adaptive Fiber Optics Collimator (AFOC) composed of phase-locking module and tip/tilt control module was developed. CBC experimental setup of three-element fiber array was established. Feedback control is realized using stochastic parallel gradient descent (SPGD) algorithm. The CBC based on TIL with piston and tip/tilt correction simultaneously is demonstrated. And the beam pointing to locate or sweep position of combined spot on target was achieved through TIL technique too. The goal of our work is achieve multi-element CBC for long-distance transmission in atmosphere.

Structural optimization of the Halbach array PM rim thrust motor

NASA Astrophysics Data System (ADS)

Cao, Haichuan; Chen, Weihu

2018-05-01

The Rim-driven Thruster (RDT) integrates the thrust motor and the propeller, which can effectively reduce the space occupied by the propulsion system, improve the propulsion efficiency, and thus has important research value and broad market prospects. The Halbach Permanent Magnet Rim Thrust Motor (HPMRTM) can improve the torque density of the propulsion motor by utilizing the unilateral magnetic field of the Halbach array. In this paper, the numerical method is used to study the electromagnetic performance of the motor under different Halbach array parameters. The relationship between motor parameters such as air-gap flux density, electromagnetic torque and Halbach array parameters is obtained, and then the motor structure is optimized. By comparing with Common Permanent Magnet RTM, the advantages of HPMRTM are verified.

Fuzzy Adaptive Control for Intelligent Autonomous Space Exploration Problems

NASA Technical Reports Server (NTRS)

Esogbue, Augustine O.

1998-01-01

The principal objective of the research reported here is the re-design, analysis and optimization of our newly developed neural network fuzzy adaptive controller model for complex processes capable of learning fuzzy control rules using process data and improving its control through on-line adaption. The learned improvement is according to a performance objective function that provides evaluative feedback; this performance objective is broadly defined to meet long-range goals over time. Although fuzzy control had proven effective for complex, nonlinear, imprecisely-defined processes for which standard models and controls are either inefficient, impractical or cannot be derived, the state of the art prior to our work showed that procedures for deriving fuzzy control, however, were mostly ad hoc heuristics. The learning ability of neural networks was exploited to systematically derive fuzzy control and permit on-line adaption and in the process optimize control. The operation of neural networks integrates very naturally with fuzzy logic. The neural networks which were designed and tested using simulation software and simulated data, followed by realistic industrial data were reconfigured for application on several platforms as well as for the employment of improved algorithms. The statistical procedures of the learning process were investigated and evaluated with standard statistical procedures (such as ANOVA, graphical analysis of residuals, etc.). The computational advantage of dynamic programming-like methods of optimal control was used to permit on-line fuzzy adaptive control. Tests for the consistency, completeness and interaction of the control rules were applied. Comparisons to other methods and controllers were made so as to identify the major advantages of the resulting controller model. Several specific modifications and extensions were made to the original controller. Additional modifications and explorations have been proposed for further study. Some of these are in progress in our laboratory while others await additional support. All of these enhancements will improve the attractiveness of the controller as an effective tool for the on line control of an array of complex process environments.

Adaptation strategies and approaches: Chapter 2

Treesearch

Patricia Butler; Chris Swanston; Maria Janowiak; Linda Parker; Matt St. Pierre; Leslie Brandt

2012-01-01

A wealth of information is available on climate change adaptation, but much of it is very broad and of limited use at the finer spatial scales most relevant to land managers. This chapter contains a "menu" of adaptation actions and provides land managers in northern Wisconsin with a range of options to help forest ecosystems adapt to climate change impacts....

Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration

DTIC Science & Technology

2007-09-01

March 17, 2005. The seismic signals from both master and detected events are followed by infrasound arrivals. Note the long duration of the...correlation coefficient traces with a significant array -gain. A detected event that is co-located with the master event will record the same time-difference...estimating the detection threshold reduction for a range of highly repeating seismic sources using arrays of different configurations and at different

LSSA (Low-cost Silicon Solar Array) project

NASA Technical Reports Server (NTRS)

1976-01-01

Methods are explored for economically generating electrical power to meet future requirements. The Low-Cost Silicon Solar Array Project (LSSA) was established to reduce the price of solar arrays by improving manufacturing technology, adapting mass production techniques, and promoting user acceptance. The new manufacturing technology includes the consideration of new silicon refinement processes, silicon sheet growth techniques, encapsulants, and automated assembly production being developed under contract by industries and universities.

Technical Objective Document. Fiscal Year 1989

DTIC Science & Technology

1987-12-01

other special interest areas/technologies; and throuch a " delphi " process with the Center Technical Investment Committee *develop a "puts and takes...radar and larce optical systems in space, the detection and trackina of low observables, and the operation of sensors for tracking objects in space for...for reducing the processing time for adaptive beamforming in receive arrays, self-coherina techniques in larce distributed arrays and array self

Immune Evasion by Epstein-Barr Virus.

PubMed

Ressing, Maaike E; van Gent, Michiel; Gram, Anna M; Hooykaas, Marjolein J G; Piersma, Sytse J; Wiertz, Emmanuel J H J

2015-01-01

Epstein-Bar virus (EBV) is widespread within the human population with over 90% of adults being infected. In response to primary EBV infection, the host mounts an antiviral immune response comprising both innate and adaptive effector functions. Although the immune system can control EBV infection to a large extent, the virus is not cleared. Instead, EBV establishes a latent infection in B lymphocytes characterized by limited viral gene expression. For the production of new viral progeny, EBV reactivates from these latently infected cells. During the productive phase of infection, a repertoire of over 80 EBV gene products is expressed, presenting a vast number of viral antigens to the primed immune system. In particular the EBV-specific CD4+ and CD8+ memory T lymphocytes can respond within hours, potentially destroying the virus-producing cells before viral replication is completed and viral particles have been released. Preceding the adaptive immune response, potent innate immune mechanisms provide a first line of defense during primary and recurrent infections. In spite of this broad range of antiviral immune effector mechanisms, EBV persists for life and continues to replicate. Studies performed over the past decades have revealed a wide array of viral gene products interfering with both innate and adaptive immunity. These include EBV-encoded proteins as well as small noncoding RNAs with immune-evasive properties. The current review presents an overview of the evasion strategies that are employed by EBV to facilitate immune escape during latency and productive infection. These evasion mechanisms may also compromise the elimination of EBV-transformed cells, and thus contribute to malignancies associated with EBV infection.

Abstract conceptual feature ratings predict gaze within written word arrays: evidence from a Visual Wor(l)d paradigm

PubMed Central

Primativo, Silvia; Reilly, Jamie; Crutch, Sebastian J

2016-01-01

The Abstract Conceptual Feature (ACF) framework predicts that word meaning is represented within a high-dimensional semantic space bounded by weighted contributions of perceptual, affective, and encyclopedic information. The ACF, like latent semantic analysis, is amenable to distance metrics between any two words. We applied predictions of the ACF framework to abstract words using eye tracking via an adaptation of the classical ‘visual word paradigm’. Healthy adults (N=20) selected the lexical item most related to a probe word in a 4-item written word array comprising the target and three distractors. The relation between the probe and each of the four words was determined using the semantic distance metrics derived from ACF ratings. Eye-movement data indicated that the word that was most semantically related to the probe received more and longer fixations relative to distractors. Importantly, in sets where participants did not provide an overt behavioral response, the fixation rates were none the less significantly higher for targets than distractors, closely resembling trials where an expected response was given. Furthermore, ACF ratings which are based on individual words predicted eye fixation metrics of probe-target similarity at least as well as latent semantic analysis ratings which are based on word co-occurrence. The results provide further validation of Euclidean distance metrics derived from ACF ratings as a measure of one facet of the semantic relatedness of abstract words and suggest that they represent a reasonable approximation of the organization of abstract conceptual space. The data are also compatible with the broad notion that multiple sources of information (not restricted to sensorimotor and emotion information) shape the organization of abstract concepts. Whilst the adapted ‘visual word paradigm’ is potentially a more metacognitive task than the classical visual world paradigm, we argue that it offers potential utility for studying abstract word comprehension. PMID:26901571

Glycans from avian influenza virus are recognized by chicken dendritic cells and are targets for the humoral immune response in chicken.

PubMed

de Geus, Eveline D; Tefsen, Boris; van Haarlem, Daphne A; van Eden, Willem; van Die, Irma; Vervelde, Lonneke

2013-12-01

To increase our understanding of the interaction between avian influenza virus and its chicken host, we identified receptors for putative avian influenza virus (AIV) glycan determinants on chicken dendritic cells. Chicken dendritic cells (DCs) were found to recognize glycan determinants containing terminal αGalNAc, Galα1-3Gal, GlcNAcβ1-4GlcNAcβ1-4GlcNAcβ (chitotriose) and Galα1-2Gal. Infection of chicken dendritic cells with either low pathogenic (LP) or highly pathogenic (HP) AIV results in elevated mRNA expression of homologs of the mouse C-type lectins DEC205 and macrophage mannose receptor (MMR), whereas expression levels of the human dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) homolog remained unchanged. Following uptake and subsequent presentation of avian influenza virus by DCs, adaptive immunity, including humoral immune responses are induced. We have investigated the antibody responses against virus glycan epitopes after avian influenza virus infection. Using glycan micro-array analysis we showed that chicken contained antibodies that predominantly recognize terminal Galα1-3Gal-R, chitotriose and Fucα1-2Galβ1-4GlcNAc-R (H-type 2). After influenza-infection, glycan array analysis showed that both levels and repertoire of glycan-recognizing antibodies decreased. However, analysis of the sera by ELISA indicated that the levels of different isotypes of anti-glycan Abs against specific glycan antigens was increased after influenza-infection, suggesting that the presentation of the glycan antigens and iso-type of the Abs are critical parameters to take into account when measuring anti-glycan Abs. This novel approach in avian influenza research may contribute to the development of a broad spectrum vaccine and improves our mechanistic understanding of innate and adaptive responses to glycans. Copyright © 2013 Elsevier Ltd. All rights reserved.

A prototype automatic phase compensation module

NASA Technical Reports Server (NTRS)

Terry, John D.

1992-01-01

The growing demands for high gain and accurate satellite communication systems will necessitate the utilization of large reflector systems. One area of concern of reflector based satellite communication is large scale surface deformations due to thermal effects. These distortions, when present, can degrade the performance of the reflector system appreciable. This performance degradation is manifested by a decrease in peak gain, and increase in sidelobe level, and pointing errors. It is essential to compensate for these distortion effects and to maintain the required system performance in the operating space environment. For this reason the development of a technique to offset the degradation effects is highly desirable. Currently, most research is direct at developing better material for the reflector. These materials have a lower coefficient of linear expansion thereby reducing the surface errors. Alternatively, one can minimize the distortion effects of these large scale errors by adaptive phased array compensation. Adaptive phased array techniques have been studied extensively at NASA and elsewhere. Presented in this paper is a prototype automatic phase compensation module designed and built at NASA Lewis Research Center which is the first stage of development for an adaptive array compensation module.

The Fuge Tube Diode Array Spectrophotometer

ERIC Educational Resources Information Center

Arneson, B. T.; Long, S. R.; Stewart, K. K.; Lagowski, J. J.

2008-01-01

We present the details for adapting a diode array UV-vis spectrophotometer to incorporate the use of polypropylene microcentrifuge tubes--fuge tubes--as cuvettes. Optical data are presented validating that the polyethylene fuge tubes are equivalent to the standard square cross section polystyrene or glass cuvettes generally used in…

Knowledge-Based Transformational Synthesis of Efficient Structures for Concurrent Computation.

DTIC Science & Technology

1985-09-30

this wire network to a smaller wire network , creation of subnetworks to replace an overly-broad fanout network , virtualization which is the creation of...dependencies among the values they contain, reduction of this wire network to a smaller wire network , " creation of subnetworks to replace an overly-broad...fanout network , "rtualization which is the creation of additional array elements and processors to reflect the internal enumera- -4 tions that

Reduction of solar vector magnetograph data using a microMSP array processor

NASA Technical Reports Server (NTRS)

Kineke, Jack

1990-01-01

The processing of raw data obtained by the solar vector magnetograph at NASA-Marshall requires extensive arithmetic operations on large arrays of real numbers. The objectives of this summer faculty fellowship study are to: (1) learn the programming language of the MicroMSP Array Processor and adapt some existing data reduction routines to exploit its capabilities; and (2) identify other applications and/or existing programs which lend themselves to array processor utilization which can be developed by undergraduate student programmers under the provisions of project JOVE.

Biological stress response terminology: Integrating the concepts of adaptive response and preconditioning stress within a hormetic dose-response framework.

PubMed

Calabrese, Edward J; Bachmann, Kenneth A; Bailer, A John; Bolger, P Michael; Borak, Jonathan; Cai, Lu; Cedergreen, Nina; Cherian, M George; Chiueh, Chuang C; Clarkson, Thomas W; Cook, Ralph R; Diamond, David M; Doolittle, David J; Dorato, Michael A; Duke, Stephen O; Feinendegen, Ludwig; Gardner, Donald E; Hart, Ronald W; Hastings, Kenneth L; Hayes, A Wallace; Hoffmann, George R; Ives, John A; Jaworowski, Zbigniew; Johnson, Thomas E; Jonas, Wayne B; Kaminski, Norbert E; Keller, John G; Klaunig, James E; Knudsen, Thomas B; Kozumbo, Walter J; Lettieri, Teresa; Liu, Shu-Zheng; Maisseu, Andre; Maynard, Kenneth I; Masoro, Edward J; McClellan, Roger O; Mehendale, Harihara M; Mothersill, Carmel; Newlin, David B; Nigg, Herbert N; Oehme, Frederick W; Phalen, Robert F; Philbert, Martin A; Rattan, Suresh I S; Riviere, Jim E; Rodricks, Joseph; Sapolsky, Robert M; Scott, Bobby R; Seymour, Colin; Sinclair, David A; Smith-Sonneborn, Joan; Snow, Elizabeth T; Spear, Linda; Stevenson, Donald E; Thomas, Yolene; Tubiana, Maurice; Williams, Gary M; Mattson, Mark P

2007-07-01

Many biological subdisciplines that regularly assess dose-response relationships have identified an evolutionarily conserved process in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism to a moderate to severe level of stress. Due to a lack of frequent interaction among scientists in these many areas, there has emerged a broad range of terms that describe such dose-response relationships. This situation has become problematic because the different terms describe a family of similar biological responses (e.g., adaptive response, preconditioning, hormesis), adversely affecting interdisciplinary communication, and possibly even obscuring generalizable features and central biological concepts. With support from scientists in a broad range of disciplines, this article offers a set of recommendations we believe can achieve greater conceptual harmony in dose-response terminology, as well as better understanding and communication across the broad spectrum of biological disciplines.

Management for adaptation

Treesearch

John Innes; Linda A. Joyce; Seppo Kellomaki; Bastiaan Louman; Aynslie Ogden; Ian Thompson; Matthew Ayres; Chin Ong; Heru Santoso; Brent Sohngen; Anita Wreford

2009-01-01

This chapter develops a framework to explore examples of adaptation options that could be used to ensure that the ecosystem services provided by forests are maintained under future climates. The services are divided into broad areas within which managers can identify specific management goals for individual forests or landscapes. Adaptation options exist for the major...

Making the Tacit Explicit: Rethinking Culturally Inclusive Pedagogy in International Student Academic Adaptation

ERIC Educational Resources Information Center

Blasco, Maribel

2015-01-01

The article proposes an approach, broadly inspired by culturally inclusive pedagogy, to facilitate international student academic adaptation based on rendering tacit aspects of local learning cultures explicit to international full degree students, rather than adapting them. Preliminary findings are presented from a focus group-based exploratory…

Means and method for the focusing and acceleration of parallel beams of charged particles

DOEpatents

Maschke, Alfred W.

1983-07-05

A novel apparatus and method for focussing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The quadrupole arrays may comprise electrodes which are shared by two or more quadrupoles. Such quadrupole arrays are particularly adapted to providing strong focussing forces for high current, high brightness, beams of charged particles, said beams further comprising a plurality of parallel beams, or beamlets, each such beamlet being focussed by one quadrupole of the array. Such arrays may be incorporated in various devices wherein beams of charged particles are accelerated or transported, such as linear accelerators, klystron tubes, beam transport lines, etc.

Memory device for two-dimensional radiant energy array computers

NASA Technical Reports Server (NTRS)

Schaefer, D. H.; Strong, J. P., III (Inventor)

1977-01-01

A memory device for two dimensional radiant energy array computers was developed, in which the memory device stores digital information in an input array of radiant energy digital signals that are characterized by ordered rows and columns. The memory device contains a radiant energy logic storing device having a pair of input surface locations for receiving a pair of separate radiant energy digital signal arrays and an output surface location adapted to transmit a radiant energy digital signal array. A regenerative feedback device that couples one of the input surface locations to the output surface location in a manner for causing regenerative feedback is also included

A low-density SNP array for analyzing differential selection in freshwater and marine populations of threespine stickleback (Gasterosteus aculeatus).

PubMed

Ferchaud, Anne-Laure; Pedersen, Susanne H; Bekkevold, Dorte; Jian, Jianbo; Niu, Yongchao; Hansen, Michael M

2014-10-06

The threespine stickleback (Gasterosteus aculeatus) has become an important model species for studying both contemporary and parallel evolution. In particular, differential adaptation to freshwater and marine environments has led to high differentiation between freshwater and marine stickleback populations at the phenotypic trait of lateral plate morphology and the underlying candidate gene Ectodysplacin (EDA). Many studies have focused on this trait and candidate gene, although other genes involved in marine-freshwater adaptation may be equally important. In order to develop a resource for rapid and cost efficient analysis of genetic divergence between freshwater and marine sticklebacks, we generated a low-density SNP (Single Nucleotide Polymorphism) array encompassing markers of chromosome regions under putative directional selection, along with neutral markers for background. RAD (Restriction site Associated DNA) sequencing of sixty individuals representing two freshwater and one marine population led to the identification of 33,993 SNP markers. Ninety-six of these were chosen for the low-density SNP array, among which 70 represented SNPs under putatively directional selection in freshwater vs. marine environments, whereas 26 SNPs were assumed to be neutral. Annotation of these regions revealed several genes that are candidates for affecting stickleback phenotypic variation, some of which have been observed in previous studies whereas others are new. We have developed a cost-efficient low-density SNP array that allows for rapid screening of polymorphisms in threespine stickleback. The array provides a valuable tool for analyzing adaptive divergence between freshwater and marine stickleback populations beyond the well-established candidate gene Ectodysplacin (EDA).

Improved neural network based scene-adaptive nonuniformity correction method for infrared focal plane arrays.

PubMed

Lai, Rui; Yang, Yin-tang; Zhou, Duan; Li, Yue-jin

2008-08-20

An improved scene-adaptive nonuniformity correction (NUC) algorithm for infrared focal plane arrays (IRFPAs) is proposed. This method simultaneously estimates the infrared detectors' parameters and eliminates the nonuniformity causing fixed pattern noise (FPN) by using a neural network (NN) approach. In the learning process of neuron parameter estimation, the traditional LMS algorithm is substituted with the newly presented variable step size (VSS) normalized least-mean square (NLMS) based adaptive filtering algorithm, which yields faster convergence, smaller misadjustment, and lower computational cost. In addition, a new NN structure is designed to estimate the desired target value, which promotes the calibration precision considerably. The proposed NUC method reaches high correction performance, which is validated by the experimental results quantitatively tested with a simulative testing sequence and a real infrared image sequence.

An experimental adaptive array to suppress weak interfering signals

NASA Technical Reports Server (NTRS)

Walton, Eric K.; Gupta, Inder J.; Ksienski, Aharon A.; Ward, James

1988-01-01

An experimental adaptive antenna system to suppress weak interfering signals is described. It is a sidelobe canceller with two auxiliary elements. Modified feedback loops are used to control the array weights. The received signals are simulated in hardware for parameter control. Digital processing is used for algorithm implementation and performance evaluation. The experimental results are presented. They show that interfering signals as much as 10 dB below the thermal noise level in the main channel are suppressed by 20-30 dB. Such a system has potential application in suppressing the interference encountered in direct broadcast satellite communication systems.

Adaptive ground implemented phase array

NASA Technical Reports Server (NTRS)

Spearing, R. E.

1973-01-01

The simulation of an adaptive ground implemented phased array of five antenna elements is reported for a very high frequency system design that is tolerant to the radio frequency interference environment encountered by a tracking data relay satellite. Signals originating from satellites are received by the VHF ring array and both horizontal and vertical polarizations from each of the five elements are multiplexed and transmitted down to ground station. A panel on the transmitting end of the simulation chamber contains up to 10 S-band RFI sources along with the desired signal to simulate the dynamic relationship between user and TDRS. The 10 input channels are summed, and desired and interference signals are separated and corrected until the resultant sum signal-to-interference ratio is maximized. Testing performed with this simulation equipment demonstrates good correlation between predicted and actual results.

Polymer-carbon black composite sensors in an electronic nose for air-quality monitoring

NASA Technical Reports Server (NTRS)

Ryan, M. A.; Shevade, A. V.; Zhou, H.; Homer, M. L.

2004-01-01

An electronic nose that uses an array of 32 polymer-carbon black composite sensors has been developed, trained, and tested. By selecting a variety of chemical functionalities in the polymers used to make sensors, it is possible to construct an array capable of identifying and quantifying a broad range of target compounds, such as alcohols and aromatics, and distinguishing isomers and enantiomers (mirror-image isomers). A model of the interaction between target molecules and the polymer-carbon black composite sensors is under development to aid in selecting the array members and to enable identification of compounds with responses not stored in the analysis library.

Fabrication and characterization of n-ZnO nanonails array/p(+)-GaN heterojunction diode.

PubMed

Zhu, G Y; Chen, G F; Li, J T; Shi, Z L; Lin, Y; Ding, T; Xu, X Y; Dai, J; Xu, C X

2012-10-01

A novel heterojunctional structure of n-ZnO nanonails array/p(+)-GaN light-emitting diode was fabricated by Chemical Vapor Deposition method. A broad electroluminescence spectrum shows two peaks centered at 435 nm and 478 nm at room temperature, respectively. By comparing the photoluminescence and electroluminescence spectra, together with analyzing the energy band structure of heterojunction light emitting diode, it suggested that the electroluminescence peak located at 435 nm originates from Mg acceptor level of p(+)-GaN layer, whereas the electroluminescence peak located at 478 nm originates from the defects of n-ZnO nanonails array.

Flat field concave holographic grating with broad spectral region and moderately high resolution.

PubMed

Wu, Jian Fen; Chen, Yong Yan; Wang, Tai Sheng

2012-02-01

In order to deal with the conflicts between broad spectral region and high resolution in compact spectrometers based on a flat field concave holographic grating and line array CCD, we present a simple and practical method to design a flat field concave holographic grating that is capable of imaging a broad spectral region at a moderately high resolution. First, we discuss the principle of realizing a broad spectral region and moderately high resolution. Second, we provide the practical method to realize our ideas, in which Namioka grating theory, a genetic algorithm, and ZEMAX are used to reach this purpose. Finally, a near-normal-incidence example modeled in ZEMAX is shown to verify our ideas. The results show that our work probably has a general applicability in compact spectrometers with a broad spectral region and moderately high resolution.

Economic Incentives: Options for Environmental Protection (1991)

EPA Pesticide Factsheets

Report of EPA Economic Incentives Task Force which develops and evaluates a broad array of economic incentive proposals. Although it does not endorse any particular proposal, it examines some of the key design and implementation issues.

Attenuator And Conditioner

DOEpatents

Anderson, Gene R.; Armendariz, Marcelino G.; Carson, Richard F.; Bryan, Robert P.; Duckett, III, Edwin B.; Kemme, Shanalyn Adair; McCormick, Frederick B.; Peterson, David W.

2006-04-04

An apparatus and method of attenuating and/or conditioning optical energy for an optical transmitter, receiver or transceiver module is disclosed. An apparatus for attenuating the optical output of an optoelectronic connector including: a mounting surface; an array of optoelectronic devices having at least a first end; an array of optical elements having at least a first end; the first end of the array of optical elements optically aligned with the first end of the array of optoelectronic devices; an optical path extending from the first end of the array of optoelectronic devices and ending at a second end of the array of optical elements; and an attenuator in the optical path for attenuating the optical energy emitted from the array of optoelectronic devices. Alternatively, a conditioner may be adapted in the optical path for conditioning the optical energy emitted from the array of optoelectronic devices.

High density arrays of micromirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Folta, J. M.; Decker, J. Y.; Kolman, J.

We established and achieved our goal to (1) fabricate and evaluate test structures based on the micromirror design optimized for maskless lithography applications, (2) perform system analysis and code development for the maskless lithography concept, and (3) identify specifications for micromirror arrays (MMAs) for LLNL's adaptive optics (AO) applications and conceptualize new devices.

Evolution of Pre- and Post-Copulatory Traits in Male Drosophila melanogaster as a Correlated Response to Selection for Resistance to Cold Stress

PubMed Central

Singh, Karan; Samant, Manas Arun; Tom, Megha Treesa; Prasad, Nagaraj Guru

2016-01-01

Background In Drosophila melanogaster the fitness of males depends on a broad array of reproductive traits classified as pre- and post-copulatory traits. Exposure to cold stress, can reduce sperm number, male mating ability and courtship behavior. Therefore, it is expected that the adaptation to cold stress will involve changes in pre- and post-copulatory traits. Such evolution of reproductive traits in response to cold stress is not well studied. Methods We selected replicate populations of D. melanogaster for resistance to cold shock. Over 37–46 generations of selection, we investigated pre- and post-copulatory traits such as mating latency, copulation duration, mating frequency, male fertility, fitness (progeny production) and sperm competitive ability in male flies subjected to cold shock and those not subjected to cold shock. Results We found that post cold shock, the males from the selected populations had a significantly lower mating latency along with, higher mating frequency, fertility, sperm competitive ability and number of progeny relative to the control populations. Conclusion While most studies of experimental evolution of cold stress resistance have documented the evolution of survivorship in response to selection, our study clearly shows that adaptation to cold stress involves rapid changes in the pre- and post-copulatory traits. Additionally, improved performances under stressful conditions need not necessarily trade-off with performance under benign conditions. PMID:27093599

The blueprint for stress can be found in invertebrates.

PubMed

Stefano, George B; Cadet, Patrick; Zhu, Wei; Rialas, Christos M; Mantione, Kirk; Benz, Danielle; Fuentes, Rudy; Casares, Federico; Fricchione, Gregory L; Fulop, Zoltan; Slingsby, Brian

2002-04-01

Through an extremely complicated equilibrium called homeostasis, all living organisms maintain their survival in the face of both externally and internally generated "stimuli". This apparent harmony is constantly challenged. Survival through successful adaptation is maintained as close to steady state as possible by adaptive responses, which may also be called perturbation responses since they have a constitutively defined dynamic capacity, i.e., an immediate limit, in a series of balancing and feedback activities reflecting an astounding array of biological, psychological and sociological behaviors. The broad spectrum of stimuli capable of engaging this protective response is remarkable. We define stress as a type of stimulation that is stronger and lasts for a longer duration, upsetting a typical perturbation response given its dynamic parameters. The stress response, which evolves out of the perturbation response, involves inducible signal molecules, i.e., cytokines. We surmise that the ability to exist in an ever-changing environment was a requirement for all life forms, including invertebrates and single celled organisms. It would be expected that these organisms exhibit both perturbation and stress responses. In this regard, we demonstrate that these organisms have mammalian-like signal molecule systems, i.e., opioid, and corresponding behaviors that are similar to those found in mammals with regard to both perturbation and stress responses. Thus, it would appear that these responses evolved first in simpler organisms and were then maintained and enhanced during evolution.

Receptor arrays optimized for natural odor statistics.

PubMed

Zwicker, David; Murugan, Arvind; Brenner, Michael P

2016-05-17

Natural odors typically consist of many molecules at different concentrations. It is unclear how the numerous odorant molecules and their possible mixtures are discriminated by relatively few olfactory receptors. Using an information theoretic model, we show that a receptor array is optimal for this task if it achieves two possibly conflicting goals: (i) Each receptor should respond to half of all odors and (ii) the response of different receptors should be uncorrelated when averaged over odors presented with natural statistics. We use these design principles to predict statistics of the affinities between receptors and odorant molecules for a broad class of odor statistics. We also show that optimal receptor arrays can be tuned to either resolve concentrations well or distinguish mixtures reliably. Finally, we use our results to predict properties of experimentally measured receptor arrays. Our work can thus be used to better understand natural olfaction, and it also suggests ways to improve artificial sensor arrays.

A robotics platform for automated batch fabrication of high density, microfluidics-based DNA microarrays, with applications to single cell, multiplex assays of secreted proteins

NASA Astrophysics Data System (ADS)

Ahmad, Habib; Sutherland, Alex; Shin, Young Shik; Hwang, Kiwook; Qin, Lidong; Krom, Russell-John; Heath, James R.

2011-09-01

Microfluidics flow-patterning has been utilized for the construction of chip-scale miniaturized DNA and protein barcode arrays. Such arrays have been used for specific clinical and fundamental investigations in which many proteins are assayed from single cells or other small sample sizes. However, flow-patterned arrays are hand-prepared, and so are impractical for broad applications. We describe an integrated robotics/microfluidics platform for the automated preparation of such arrays, and we apply it to the batch fabrication of up to eighteen chips of flow-patterned DNA barcodes. The resulting substrates are comparable in quality with hand-made arrays and exhibit excellent substrate-to-substrate consistency. We demonstrate the utility and reproducibility of robotics-patterned barcodes by utilizing two flow-patterned chips for highly parallel assays of a panel of secreted proteins from single macrophage cells.

A robotics platform for automated batch fabrication of high density, microfluidics-based DNA microarrays, with applications to single cell, multiplex assays of secreted proteins

PubMed Central

Ahmad, Habib; Sutherland, Alex; Shin, Young Shik; Hwang, Kiwook; Qin, Lidong; Krom, Russell-John; Heath, James R.

2011-01-01

Microfluidics flow-patterning has been utilized for the construction of chip-scale miniaturized DNA and protein barcode arrays. Such arrays have been used for specific clinical and fundamental investigations in which many proteins are assayed from single cells or other small sample sizes. However, flow-patterned arrays are hand-prepared, and so are impractical for broad applications. We describe an integrated robotics/microfluidics platform for the automated preparation of such arrays, and we apply it to the batch fabrication of up to eighteen chips of flow-patterned DNA barcodes. The resulting substrates are comparable in quality with hand-made arrays and exhibit excellent substrate-to-substrate consistency. We demonstrate the utility and reproducibility of robotics-patterned barcodes by utilizing two flow-patterned chips for highly parallel assays of a panel of secreted proteins from single macrophage cells. PMID:21974603

A robotics platform for automated batch fabrication of high density, microfluidics-based DNA microarrays, with applications to single cell, multiplex assays of secreted proteins.

PubMed

Ahmad, Habib; Sutherland, Alex; Shin, Young Shik; Hwang, Kiwook; Qin, Lidong; Krom, Russell-John; Heath, James R

2011-09-01

Microfluidics flow-patterning has been utilized for the construction of chip-scale miniaturized DNA and protein barcode arrays. Such arrays have been used for specific clinical and fundamental investigations in which many proteins are assayed from single cells or other small sample sizes. However, flow-patterned arrays are hand-prepared, and so are impractical for broad applications. We describe an integrated robotics/microfluidics platform for the automated preparation of such arrays, and we apply it to the batch fabrication of up to eighteen chips of flow-patterned DNA barcodes. The resulting substrates are comparable in quality with hand-made arrays and exhibit excellent substrate-to-substrate consistency. We demonstrate the utility and reproducibility of robotics-patterned barcodes by utilizing two flow-patterned chips for highly parallel assays of a panel of secreted proteins from single macrophage cells. © 2011 American Institute of Physics

Initial astronomical results with a new 5-14 micron Si:Ga 58x62 DRO array camera

NASA Technical Reports Server (NTRS)

Gezari, Dan; Folz, Walter; Woods, Larry

1989-01-01

A new array camera system was developed using a 58 x 62 pixel Si:Ga (gallium doped silicon) DRO (direct readout) photoconductor array detector manufactured by Hughes/Santa Barbara Research Center (SBRC). The camera system is a broad band photometer designed for 5 to 14 micron imaging with large ground-based optical telescopes. In a typical application a 10 micron photon flux of about 10(exp 9) photons sec(exp -1) m(exp -2) microns(exp -1) arcsec(exp -2) is incident in the telescope focal plane, while the detector well capacity of these arrays is 10(exp 5) to 10 (exp 6) electrons. However, when the real efficiencies and operating conditions are accounted for, the 2-channel 3596 pixel array operates with about 1/2 full wells at 10 micron and 10% bandwidth with high duty cycle and no real experimental compromises.

Holographic injection locking of a broad area laser diode via a photorefractive thin-film device.

PubMed

van Voorst, P D; de Wit, M R; Offerhaus, H L; Tay, S; Thomas, J; Peyghambarian, N; Boller, K-J

2007-12-24

We demonstrate locking of a high power broad area laser diode to a single frequency using holographic feedback from a photorefractive polymer thin-film device for the first time. A four-wave mixing setup is used to generate feedback for the broad area diode at the wavelength of the single frequency source (Ti:Sapphire laser) while the spatial distribution adapts to the preferred profile of the broad area diode. The result is an injection-locked broad area diode emitting with a linewidth comparable to the Ti:Sapphire laser.

Micromachined electrode array

DOEpatents

Okandan, Murat; Wessendorf, Kurt O.

2007-12-11

An electrode array is disclosed which has applications for neural stimulation and sensing. The electrode array, in certain embodiments, can include a plurality of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. In other embodiments of the electrode array, the electrodes can be fixed to the substrate. The electrode array can be formed from a combination of bulk and surface micromachining, and can include electrode tips having an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis.

Determining Methane Leak Locations and Rates with a Wireless Network Composed of Low-Cost, Printed Sensors

NASA Astrophysics Data System (ADS)

Smith, C. J.; Kim, B.; Zhang, Y.; Ng, T. N.; Beck, V.; Ganguli, A.; Saha, B.; Daniel, G.; Lee, J.; Whiting, G.; Meyyappan, M.; Schwartz, D. E.

2015-12-01

We will present our progress on the development of a wireless sensor network that will determine the source and rate of detected methane leaks. The targeted leak detection threshold is 2 g/min with a rate estimation error of 20% and localization error of 1 m within an outdoor area of 100 m2. The network itself is composed of low-cost, high-performance sensor nodes based on printed nanomaterials with expected sensitivity below 1 ppmv methane. High sensitivity to methane is achieved by modifying high surface-area-to-volume-ratio single-walled carbon nanotubes (SWNTs) with materials that adsorb methane molecules. Because the modified SWNTs are not perfectly selective to methane, the sensor nodes contain arrays of variously-modified SWNTs to build diversity of response towards gases with adsorption affinity. Methane selectivity is achieved through advanced pattern-matching algorithms of the array's ensemble response. The system is low power and designed to operate for a year on a single small battery. The SWNT sensing elements consume only microwatts. The largest power consumer is the wireless communication, which provides robust, real-time measurement data. Methane leak localization and rate estimation will be performed by machine-learning algorithms built with the aid of computational fluid dynamics simulations of gas plume formation. This sensor system can be broadly applied at gas wells, distribution systems, refineries, and other downstream facilities. It also can be utilized for industrial and residential safety applications, and adapted to other gases and gas combinations.

75 FR 54872 - Drinking Water Strategy Contaminants as Group(s)-Notice of Public Stakeholder Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-09

... technologies to address health risks posed by a broad array of contaminants; using the authority of multiple... potential contaminant groups, share advantages and disadvantages of various groups, identify issues needing...

Subwavelength grating enabled on-chip ultra-compact optical true time delay line

PubMed Central

Wang, Junjia; Ashrafi, Reza; Adams, Rhys; Glesk, Ivan; Gasulla, Ivana; Capmany, José; Chen, Lawrence R.

2016-01-01

An optical true time delay line (OTTDL) is a basic photonic building block that enables many microwave photonic and optical processing operations. The conventional design for an integrated OTTDL that is based on spatial diversity uses a length-variable waveguide array to create the optical time delays, which can introduce complexities in the integrated circuit design. Here we report the first ever demonstration of an integrated index-variable OTTDL that exploits spatial diversity in an equal length waveguide array. The approach uses subwavelength grating waveguides in silicon-on-insulator (SOI), which enables the realization of OTTDLs having a simple geometry and that occupy a compact chip area. Moreover, compared to conventional wavelength-variable delay lines with a few THz operation bandwidth, our index-variable OTTDL has an extremely broad operation bandwidth practically exceeding several tens of THz, which supports operation for various input optical signals with broad ranges of central wavelength and bandwidth. PMID:27457024

Subwavelength grating enabled on-chip ultra-compact optical true time delay line.

PubMed

Wang, Junjia; Ashrafi, Reza; Adams, Rhys; Glesk, Ivan; Gasulla, Ivana; Capmany, José; Chen, Lawrence R

2016-07-26

An optical true time delay line (OTTDL) is a basic photonic building block that enables many microwave photonic and optical processing operations. The conventional design for an integrated OTTDL that is based on spatial diversity uses a length-variable waveguide array to create the optical time delays, which can introduce complexities in the integrated circuit design. Here we report the first ever demonstration of an integrated index-variable OTTDL that exploits spatial diversity in an equal length waveguide array. The approach uses subwavelength grating waveguides in silicon-on-insulator (SOI), which enables the realization of OTTDLs having a simple geometry and that occupy a compact chip area. Moreover, compared to conventional wavelength-variable delay lines with a few THz operation bandwidth, our index-variable OTTDL has an extremely broad operation bandwidth practically exceeding several tens of THz, which supports operation for various input optical signals with broad ranges of central wavelength and bandwidth.

Taking a Broad Approach to Public Health Program Adaptation: Adapting a Family-Based Diabetes Education Program

ERIC Educational Resources Information Center

Reinschmidt, Kerstin M.; Teufel-Shone, Nicolette I.; Bradford, Gail; Drummond, Rebecca L.; Torres, Emma; Redondo, Floribella; Elenes, Jo Jean; Sanders, Alicia; Gastelum, Sylvia; Moore-Monroy, Martha; Barajas, Salvador; Fernandez, Lourdes; Alvidrez, Rosy; de Zapien, Jill Guernsey; Staten, Lisa K.

2010-01-01

Diabetes health disparities among Hispanic populations have been countered with federally funded health promotion and disease prevention programs. Dissemination has focused on program adaptation to local cultural contexts for greater acceptability and sustainability. Taking a broader approach and drawing on our experience in Mexican American…

Improving Tumor Treating Fields Treatment Efficacy in Patients With Glioblastoma Using Personalized Array Layouts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wenger, Cornelia, E-mail: cwenger@fc.ul.pt; Salvador, Ricardo; Basser, Peter J.

Purpose: To investigate tumors of different size, shape, and location and the effect of varying transducer layouts on Tumor Treating Fields (TTFields) distribution in an anisotropic model. Methods and Materials: A realistic human head model was generated from MR images of 1 healthy subject. Four different virtual tumors were placed at separate locations. The transducer arrays were modeled to mimic the TTFields-delivering commercial device. For each tumor location, varying array layouts were tested. The finite element method was used to calculate the electric field distribution, taking into account tissue heterogeneity and anisotropy. Results: In all tumors, the average electric field inducedmore » by either of the 2 perpendicular array layouts exceeded the 1-V/cm therapeutic threshold value for TTFields effectiveness. Field strength within a tumor did not correlate with its size and shape but was higher in more superficial tumors. Additionally, it always increased when the array was adapted to the tumor's location. Compared with a default layout, the largest increase in field strength was 184%, and the highest average field strength induced in a tumor was 2.21 V/cm. Conclusions: These results suggest that adapting array layouts to specific tumor locations can significantly increase field strength within the tumor. Our findings support the idea of personalized treatment planning to increase TTFields efficacy for patients with GBM.« less

Analysis and design of a high power laser adaptive phased array transmitter

NASA Technical Reports Server (NTRS)

Mevers, G. E.; Soohoo, J. F.; Winocur, J.; Massie, N. A.; Southwell, W. H.; Brandewie, R. A.; Hayes, C. L.

1977-01-01

The feasibility of delivering substantial quantities of optical power to a satellite in low earth orbit from a ground based high energy laser (HEL) coupled to an adaptive antenna was investigated. Diffraction effects, atmospheric transmission efficiency, adaptive compensation for atmospheric turbulence effects, including the servo bandwidth requirements for this correction, and the adaptive compensation for thermal blooming were examined. To evaluate possible HEL sources, atmospheric investigations were performed for the CO2, (C-12)(O-18)2 isotope, CO and DF wavelengths using output antenna locations of both sea level and mountain top. Results indicate that both excellent atmospheric and adaption efficiency can be obtained for mountain top operation with a micron isotope laser operating at 9.1 um, or a CO laser operating single line (P10) at about 5.0 (C-12)(O-18)2um, which was a close second in the evaluation. Four adaptive power transmitter system concepts were generated and evaluated, based on overall system efficiency, reliability, size and weight, advanced technology requirements and potential cost. A multiple source phased array was selected for detailed conceptual design. The system uses a unique adaption technique of phase locking independent laser oscillators which allows it to be both relatively inexpensive and most reliable with a predicted overall power transfer efficiency of 53%.

New perspective on single-radiator multiple-port antennas for adaptive beamforming applications.

PubMed

Byun, Gangil; Choo, Hosung

2017-01-01

One of the most challenging problems in recent antenna engineering fields is to achieve highly reliable beamforming capabilities in an extremely restricted space of small handheld devices. In this paper, we introduce a new perspective on single-radiator multiple-port (SRMP) antenna to alter the traditional approach of multiple-antenna arrays for improving beamforming performances with reduced aperture sizes. The major contribution of this paper is to demonstrate the beamforming capability of the SRMP antenna for use as an extremely miniaturized front-end component in more sophisticated beamforming applications. To examine the beamforming capability, the radiation properties and the array factor of the SRMP antenna are theoretically formulated for electromagnetic characterization and are used as complex weights to form adaptive array patterns. Then, its fundamental performance limits are rigorously explored through enumerative studies by varying the dielectric constant of the substrate, and field tests are conducted using a beamforming hardware to confirm the feasibility. The results demonstrate that the new perspective of the SRMP antenna allows for improved beamforming performances with the ability of maintaining consistently smaller aperture sizes compared to the traditional multiple-antenna arrays.

Modeling of high-precision wavefront sensing with new generation of CMT avalanche photodiode infrared detectors.

PubMed

Gousset, Silvère; Petit, Cyril; Michau, Vincent; Fusco, Thierry; Robert, Clelia

2015-12-01

Near-infrared wavefront sensing allows for the enhancement of sky coverage with adaptive optics. The recently developed HgCdTe avalanche photodiode arrays are promising due to their very low detector noise, but still present an imperfect cosmetic that may directly impact real-time wavefront measurements for adaptive optics and thus degrade performance in astronomical applications. We propose here a model of a Shack-Hartmann wavefront measurement in the presence of residual fixed pattern noise and defective pixels. To adjust our models, a fine characterization of such an HgCdTe array, the RAPID sensor, is proposed. The impact of the cosmetic defects on the Shack-Hartmann measurement is assessed through numerical simulations. This study provides both a new insight on the applicability of cadmium mercury telluride (CMT) avalanche photodiodes detectors for astronomical applications and criteria to specify the cosmetic qualities of future arrays.

Sensor modeling and demonstration of a multi-object spectrometer for performance-driven sensing

NASA Astrophysics Data System (ADS)

Kerekes, John P.; Presnar, Michael D.; Fourspring, Kenneth D.; Ninkov, Zoran; Pogorzala, David R.; Raisanen, Alan D.; Rice, Andrew C.; Vasquez, Juan R.; Patel, Jeffrey P.; MacIntyre, Robert T.; Brown, Scott D.

2009-05-01

A novel multi-object spectrometer (MOS) is being explored for use as an adaptive performance-driven sensor that tracks moving targets. Developed originally for astronomical applications, the instrument utilizes an array of micromirrors to reflect light to a panchromatic imaging array. When an object of interest is detected the individual micromirrors imaging the object are tilted to reflect the light to a spectrometer to collect a full spectrum. This paper will present example sensor performance from empirical data collected in laboratory experiments, as well as our approach in designing optical and radiometric models of the MOS channels and the micromirror array. Simulation of moving vehicles in a highfidelity, hyperspectral scene is used to generate a dynamic video input for the adaptive sensor. Performance-driven algorithms for feature-aided target tracking and modality selection exploit multiple electromagnetic observables to track moving vehicle targets.

Creating a Forest-Wide Context for Adaptive Management at Jackson Demonstration State Forest

NASA Astrophysics Data System (ADS)

Liquori, M.; Helms, J.; Porter, D.

2010-12-01

At nearly 50,000 acres, Jackson Demonstration State Forest (JDSF) is the largest State-owned forest in California. In 2008, the CALFIRE Director appointed a 13-member Jackson Advisory Group to provide recommendations to the California State Board of Forestry for how to transition JDSF into a “world-class research forest”. After nearly 3 years of deliberations, we have developed a draft Research-Oriented Management Framework (ROMF) that, if adopted, will introduce a new model for adaptive management within the forestry sector. Our approach integrates several core elements. Scientific “Centers of Excellence” (including one focused on Coho recovery and/or watershed processes) would be developed around a Research-Oriented Landscape Allocation, that considers the existing distribution of forest attributes both within JDSF as well as within the broader coastal Redwood Region. The ROMF would establish an Experimental Basis for Management that seeks to leverage harvest activities with explicit experimental designs and monitoring objectives. Like many of the forests that comprise its customer-base, JDSF has a mandate to produce timber revenues. We view this as an opportunity to mimic the management constraint imposed on most private and conservation trust landowners to routinely harvest timber to support operational and capital costs. Timber revenues on JDSF would be used (in part) to support the research and monitoring program. Such a system would support both passive and active modes of forest manipulation and research, and would make JDSF research activities more relevant to stakeholders, potentially increasing opportunities for collaborative, landscape-scale studies that seek to resolve outstanding management issues and uncertainties. The ROMF also would seek to develop and improve practices related to sustainable forestry. Both Late-Seral Development Areas and Old-Forest Structure Zones would be established that will utilize uneven-aged management treatments to expedite a distribution of forest stand characteristics ranging from young to old. This system would provide the context for research and monitoring involving a wide array of hydro-geomorphic and ecological issues, while concentrating efforts into collaborative Centers of Excellence. Together, these ROMF elements can provide a backbone for adaptive management that will be relevant to a broad array of stakeholders, including landowners, agencies, conservation groups and policy makers.

Opto-VLSI-based photonic true-time delay architecture for broadband adaptive nulling in phased array antennas.

PubMed

Juswardy, Budi; Xiao, Feng; Alameh, Kamal

2009-03-16

This paper proposes a novel Opto-VLSI-based tunable true-time delay generation unit for adaptively steering the nulls of microwave phased array antennas. Arbitrary single or multiple true-time delays can simultaneously be synthesized for each antenna element by slicing an RF-modulated broadband optical source and routing specific sliced wavebands through an Opto-VLSI processor to a high-dispersion fiber. Experimental results are presented, which demonstrate the principle of the true-time delay unit through the generation of 5 arbitrary true-time delays of up to 2.5 ns each. (c) 2009 Optical Society of America

Amplitude and intensity spatial interferometry; Proceedings of the Meeting, Tucson, AZ, Feb. 14-16, 1990

NASA Technical Reports Server (NTRS)

Breckinridge, Jim B. (Editor)

1990-01-01

Attention is given to such topics as ground interferometers, space interferometers, speckle-based and interferometry-based astronomical observations, adaptive and atmospheric optics, speckle techniques, and instrumentation. Particular papers are presented concerning recent progress on the IR Michelson array; the IOTA interferometer project; a space interferometer concept for the detection of extrasolar earth-like planets; IR speckle imaging at Palomar; optical diameters of stars measured with the Mt. Wilson Mark III interferometer; the IR array camera for interferometry with the cophased Multiple Mirror Telescope; optimization techniques appliesd to the bispectrum of one-dimensional IR astronomical speckle data; and adaptive optical iamging for extended objects.

Directed self-organization of single DNA molecules in a nanoslit via embedded nanopit arrays

PubMed Central

Reisner, Walter; Larsen, Niels B.; Flyvbjerg, Henrik; Tegenfeldt, Jonas O.; Kristensen, Anders

2009-01-01

We show that arrays of nanopit structures etched in a nanoslit can control the positioning and conformation of single DNA molecules in nanofluidic devices. By adjusting the spacing, organization and placement of the nanopits it is possible to immobilize DNA at predetermined regions of a device without additional chemical modification and achieve a high degree of control over local DNA conformation. DNA can be extended between two nanopits and in closely spaced arrays will self-assemble into “connect-the-dots” conformations consisting of locally pinned segments joined by fluctuating linkers. These results have broad implications for nanotechnology fields that require methods for the nanoscale positioning and manipulation of DNA. PMID:19122138

True-time-delay photonic beamformer for an L-band phased array radar

NASA Astrophysics Data System (ADS)

Zmuda, Henry; Toughlian, Edward N.; Payson, Paul M.; Malowicki, John E.

1995-10-01

The problem of obtaining a true-time-delay photonic beamformer has recently been a topic of great interest. Many interesting and novel approaches to this problem have been studied. This paper examines the design, construction, and testing of a dynamic optical processor for the control of a 20-element phased array antenna operating at L-band (1.2-1.4 GHz). The approach taken here has several distinct advantages. The actual optical control is accomplished with a class of spatial light modulator known as a segmented mirror device (SMD). This allows for the possibility of controlling an extremely large number (tens of thousands) of antenna elements using integrated circuit technology. The SMD technology is driven by the HDTV and laser printer markets so ultimate cost reduction as well as technological improvements are expected. Optical splitting is efficiently accomplished using a diffractive optical element. This again has the potential for use in antenna array systems with a large number of radiating elements. The actual time delay is achieved using a single acousto-optic device for all the array elements. Acousto-optic device technologies offer sufficient delay as needed for a time steered array. The topological configuration is an optical heterodyne system, hence high, potentially millimeter wave center frequencies are possible by mixing two lasers of slightly differing frequencies. Finally, the entire system is spatially integrated into a 3D glass substrate. The integrated system provides the ruggedness needed in most applications and essentially eliminates the drift problems associated with free space optical systems. Though the system is presently being configured as a beamformer, it has the ability to operate as a general photonic signal processing element in an adaptive (reconfigurable) transversal frequency filter configuration. Such systems are widely applicable in jammer/noise canceling systems, broadband ISDN, and for spread spectrum secure communications. This paper also serves as an update of work-in-progress at the Rome Laboratory Photonics Center Optical Beamforming Lab. The multi-faceted aspects of the design and construction of this state-of-the-art beamforming project will be discussed. Experimental results which demonstrate the performance of the system to-date with regard to both maximum delay and resolution over a broad bandwidth are presented.

Active Acoustic Array for Ultrasonic Biomedical Applications

DTIC Science & Technology

2001-07-30

of the human anatomy and means to 3 acoustically couple the acoustic array to the portion of the 4 human anatomy . The acoustic array is doubly...ultrasonic sound wave to be generated into the portion 14 of the 22 human anatomy . As previously mentioned, each of the acoustic 23 elements 28 acts as...human breast, it should be 3 recognized that the device can be adapted to detect cancer in 4 other portions of the human anatomy . 5 It is apparent

Adaptive Optics Communications Performance Analysis

NASA Technical Reports Server (NTRS)

Srinivasan, M.; Vilnrotter, V.; Troy, M.; Wilson, K.

2004-01-01

The performance improvement obtained through the use of adaptive optics for deep-space communications in the presence of atmospheric turbulence is analyzed. Using simulated focal-plane signal-intensity distributions, uncoded pulse-position modulation (PPM) bit-error probabilities are calculated assuming the use of an adaptive focal-plane detector array as well as an adaptively sized single detector. It is demonstrated that current practical adaptive optics systems can yield performance gains over an uncompensated system ranging from approximately 1 dB to 6 dB depending upon the PPM order and background radiation level.

A practical approach for translating climate change adaptation principles into forest management actions

Treesearch

Maria K. Janowiak; Christopher W. Swanston; Linda M. Nagel; Leslie A. Brandt; Patricia R. Butler; Stephen D. Handler; P. Danielle Shannon; Louis R. Iverson; Stephen N. Matthews; Anantha Prasad; Matthew P. Peters

2014-01-01

There is an ever-growing body of literature on forest management strategies for climate change adaptation; however, few frameworks have been presented for integrating these strategies with the real-world challenges of forest management. We have developed a structured approach for translating broad adaptation concepts into specific management actions and silvicultural...

Process-morphology scaling relations quantify self-organization in capillary densified nanofiber arrays.

PubMed

Kaiser, Ashley L; Stein, Itai Y; Cui, Kehang; Wardle, Brian L

2018-02-07

Capillary-mediated densification is an inexpensive and versatile approach to tune the application-specific properties and packing morphology of bulk nanofiber (NF) arrays, such as aligned carbon nanotubes. While NF length governs elasto-capillary self-assembly, the geometry of cellular patterns formed by capillary densified NFs cannot be precisely predicted by existing theories. This originates from the recently quantified orders of magnitude lower than expected NF array effective axial elastic modulus (E), and here we show via parametric experimentation and modeling that E determines the width, area, and wall thickness of the resulting cellular pattern. Both experiments and models show that further tuning of the cellular pattern is possible by altering the NF-substrate adhesion strength, which could enable the broad use of this facile approach to predictably pattern NF arrays for high value applications.

Graphene-Based Chemical Vapor Sensors for Electronic Nose Applications

NASA Astrophysics Data System (ADS)

Nallon, Eric C.

An electronic nose (e-nose) is a biologically inspired device designed to mimic the operation of the olfactory system. The e-nose utilizes a chemical sensor array consisting of broadly responsive vapor sensors, whose combined response produces a unique pattern for a given compound or mixture. The sensor array is inspired by the biological function of the receptor neurons found in the human olfactory system, which are inherently cross-reactive and respond to many different compounds. The use of an e-nose is an attractive approach to predict unknown odors and is used in many fields for quantitative and qualitative analysis. If properly designed, an e-nose has the potential to adapt to new odors it was not originally designed for through laboratory training and algorithm updates. This would eliminate the lengthy and costly R&D costs associated with materiel and product development. Although e-nose technology has been around for over two decades, much research is still being undertaken in order to find new and more diverse types of sensors. Graphene is a single-layer, 2D material comprised of carbon atoms arranged in a hexagonal lattice, with extraordinary electrical, mechanical, thermal and optical properties due to its 2D, sp2-bonded structure. Graphene has much potential as a chemical sensing material due to its 2D structure, which provides a surface entirely exposed to its surrounding environment. In this configuration, every carbon atom in graphene is a surface atom, providing the greatest possible surface area per unit volume, so that electron transport is highly sensitive to adsorbed molecular species. Graphene has gained much attention since its discovery in 2004, but has not been realized in many commercial electronics. It has the potential to be a revolutionary material for use in chemical sensors due to its excellent conductivity, large surface area, low noise, and versatile surface for functionalization. In this work, graphene is incorporated into a chemiresistor device and used as a chemical sensor, where its resistance is temporarily modified while exposed to chemical compounds. The inherent, broad selective nature of graphene is demonstrated by testing a sensor against a diverse set of volatile organic compounds and also against a set of chemically similar compounds. The sensor exhibits excellent selectivity and is capable of achieving high classification accuracies. The kinetics of the sensor's response are further investigated revealing a relationship between the transient behavior of the response curve and physiochemical properties of the compounds, such as the molar mass and vapor pressure. This kinetic information is also shown to provide important information for further pattern recognition and classification, which is demonstrated by increased classification accuracy of very similar compounds. Covalent modification of the graphene surface is demonstrated by means of plasma treatment and free radical exchange, and sensing performance compared to an unmodified graphene sensor. Finally, the first example of a graphene-based, cross-reactive chemical sensor array is demonstrated by applying various polymers as coatings over an array of graphene sensors. The sensor array is tested against a variety of compounds, including the complex odor of Scotch whiskies, where it is capable of perfect classification of 10 Scotch whiskey variations.

Studies of thermal wave phenomena on the Jovian planets

NASA Technical Reports Server (NTRS)

Deming, Drake

1991-01-01

Ground based and Voyager observations of Jupiter have provided evidence that the tropospheric temperature shows global scale longitudinal variations which are often wavelike in character. Voyager data are reported to exhibit the presence of slowly moving thermal features, wherein the jovian tropospheric temperature patterns are not advected by the equatorial zonal winds, but are not found to rotate at the System III (interior) rate. Ground based data in a broad infrared band (8 to 13 micron) show a wavelike structure whose amplitude and spatial scale are similar to the reported properties of the slowly moving thermal features. This study is directed toward obtaining additional ground based data in infrared spectral bands whose contribution functions are optimized for specific atmospheric regions (tropospheric at 20 micron, and stratospheric at 7.8 micron), in order to confirm the previous results, and to identify the nature and physical significance of wavelike longitudinal temperature fluctuations on the Jovian planets. A 2-D infrared array detector and low resolution cryogenic grating spectrometer is being adapted to obtain maps in approx. 2/cm bandpasses.

Microscale Adaptation of In Vitro Transcription/Translation for High-Throughput Screening of Natural Product Extract Libraries.

PubMed

Lowell, Andrew N; Santoro, Nicholas; Swaney, Steven M; McQuade, Thomas J; Schultz, Pamela J; Larsen, Martha J; Sherman, David H

2015-12-01

Novel antimicrobials that effectively inhibit bacterial growth are essential to fight the growing threat of antibiotic resistance. A promising target is the bacterial ribosome, a 2.5 MDa organelle susceptible to several biorthogonal modes of action used by different classes of antibiotics. To promote the discovery of unique inhibitors, we have miniaturized a coupled transcription/translation assay using E. coli and applied it to screen a natural product library of ~30 000 extracts. We significantly reduced the scale of the assay to 2 μL in a 1536-well plate format and decreased the effective concentration of costly reagents. The improved assay returned 1327 hits (4.6% hit rate) with %CV and Z' values of 8.5% and 0.74, respectively. This assay represents a significant advance in molecular screening, both in miniaturization and its application to a natural product extract library, and we intend to apply it to a broad array of pathogenic microbes in the search for novel anti-infective agents. © 2015 John Wiley & Sons A/S.

Miniaturized spectrometer for stand-off chemical detection

NASA Astrophysics Data System (ADS)

Henning, Patrick F.; Chadha, Suneet; Damren, Richard; Rowe, Rebecca C.; Stevenson, Chuck; Curtiss, Lawrence E.; DiGiuseppe, Thomas G.

2002-02-01

Advanced autonomous detection of both chemical warfare agents and toxic industrial chemicals has long been of major military concern and is becoming an increasingly realistic need. Foster-Miller has successfully designed and demonstrated a high spectral throughput monolithic wedge spectrometer capable of providing early, stand-off detection of chemical threats. Recent breakthrough innovations in IR source technologies, high D* multispectral array detectors, and IR waveguide materials has allowed for the development of a robust, miniature, monolithic infrared spectrometer. Foster-Miller recently demonstrated a high resolution spectrometer operating in the 8 to 12 micron region for chemical agent detection. Results will be presented demonstrating the feasibility of adapting the wedge spectrometer to operate as an upward looking ground sensor for stand-off chemical detection. Our miniaturized spectrometer forms the basis for deploying low cost, lightweight sensors which may be used for reconnaissance missions or delivered to remote locations for unattended operation. The ability of perform passive stand-off infrared chemical agent and chemical emissions detection with a low cost, compact device that can operate autonomously in remote environments has broad applications in both the military and commercial marketplace.

Electrically switchable metadevices via graphene

PubMed Central

Balci, Osman; Kakenov, Nurbek; Karademir, Ertugrul; Balci, Sinan; Cakmakyapan, Semih; Polat, Emre O.; Caglayan, Humeyra; Özbay, Ekmel; Kocabas, Coskun

2018-01-01

Metamaterials bring subwavelength resonating structures together to overcome the limitations of conventional materials. The realization of active metadevices has been an outstanding challenge that requires electrically reconfigurable components operating over a broad spectrum with a wide dynamic range. However, the existing capability of metamaterials is not sufficient to realize this goal. By integrating passive metamaterials with active graphene devices, we demonstrate a new class of electrically controlled active metadevices working in microwave frequencies. The fabricated active metadevices enable efficient control of both amplitude (>50 dB) and phase (>90°) of electromagnetic waves. In this hybrid system, graphene operates as a tunable Drude metal that controls the radiation of the passive metamaterials. Furthermore, by integrating individually addressable arrays of metadevices, we demonstrate a new class of spatially varying digital metasurfaces where the local dielectric constant can be reconfigured with applied bias voltages. In addition, we reconfigure resonance frequency of split-ring resonators without changing its amplitude by damping one of the two coupled metasurfaces via graphene. Our approach is general enough to implement various metamaterial systems that could yield new applications ranging from electrically switchable cloaking devices to adaptive camouflage systems. PMID:29322094

Modelling of the frictional behaviour of the snake skin covered by anisotropic surface nanostructures.

PubMed

Filippov, Alexander E; Gorb, Stanislav N

2016-03-23

Previous experimental data clearly revealed anisotropic friction on the ventral scale surface of snakes. However, it is known that frictional properties of the ventral surface of the snake skin range in a very broad range and the degree of anisotropy ranges as well to a quite strong extent. This might be due to the variety of species studied, diversity of approaches used for the friction characterization, and/or due to the variety of substrates used as a counterpart in the experiments. In order to understand the interactions between the nanostructure arrays of the ventral surface of the snake skin, this study was undertaken, which is aimed at numerical modeling of frictional properties of the structurally anisotropic surfaces in contact with various size of asperities. The model shows that frictional anisotropy appears on the snake skin only on the substrates with a characteristic range of roughness, which is less or comparable with dimensions of the skin microstructure. In other words, scale of the skin relief should reflect an adaptation to the particular range of surfaces asperities of the substrate.

Modelling of the frictional behaviour of the snake skin covered by anisotropic surface nanostructures

PubMed Central

Filippov, Alexander E.; Gorb, Stanislav N.

2016-01-01

Previous experimental data clearly revealed anisotropic friction on the ventral scale surface of snakes. However, it is known that frictional properties of the ventral surface of the snake skin range in a very broad range and the degree of anisotropy ranges as well to a quite strong extent. This might be due to the variety of species studied, diversity of approaches used for the friction characterization, and/or due to the variety of substrates used as a counterpart in the experiments. In order to understand the interactions between the nanostructure arrays of the ventral surface of the snake skin, this study was undertaken, which is aimed at numerical modeling of frictional properties of the structurally anisotropic surfaces in contact with various size of asperities. The model shows that frictional anisotropy appears on the snake skin only on the substrates with a characteristic range of roughness, which is less or comparable with dimensions of the skin microstructure. In other words, scale of the skin relief should reflect an adaptation to the particular range of surfaces asperities of the substrate. PMID:27005001

Modelling of the frictional behaviour of the snake skin covered by anisotropic surface nanostructures

NASA Astrophysics Data System (ADS)

Filippov, Alexander E.; Gorb, Stanislav N.

2016-03-01

Previous experimental data clearly revealed anisotropic friction on the ventral scale surface of snakes. However, it is known that frictional properties of the ventral surface of the snake skin range in a very broad range and the degree of anisotropy ranges as well to a quite strong extent. This might be due to the variety of species studied, diversity of approaches used for the friction characterization, and/or due to the variety of substrates used as a counterpart in the experiments. In order to understand the interactions between the nanostructure arrays of the ventral surface of the snake skin, this study was undertaken, which is aimed at numerical modeling of frictional properties of the structurally anisotropic surfaces in contact with various size of asperities. The model shows that frictional anisotropy appears on the snake skin only on the substrates with a characteristic range of roughness, which is less or comparable with dimensions of the skin microstructure. In other words, scale of the skin relief should reflect an adaptation to the particular range of surfaces asperities of the substrate.

The Evolution of Chemical High-Throughput Experimentation To Address Challenging Problems in Pharmaceutical Synthesis.

PubMed

Krska, Shane W; DiRocco, Daniel A; Dreher, Spencer D; Shevlin, Michael

2017-12-19

The structural complexity of pharmaceuticals presents a significant challenge to modern catalysis. Many published methods that work well on simple substrates often fail when attempts are made to apply them to complex drug intermediates. The use of high-throughput experimentation (HTE) techniques offers a means to overcome this fundamental challenge by facilitating the rational exploration of large arrays of catalysts and reaction conditions in a time- and material-efficient manner. Initial forays into the use of HTE in our laboratories for solving chemistry problems centered around screening of chiral precious-metal catalysts for homogeneous asymmetric hydrogenation. The success of these early efforts in developing efficient catalytic steps for late-stage development programs motivated the desire to increase the scope of this approach to encompass other high-value catalytic chemistries. Doing so, however, required significant advances in reactor and workflow design and automation to enable the effective assembly and agitation of arrays of heterogeneous reaction mixtures and retention of volatile solvents under a wide range of temperatures. Associated innovations in high-throughput analytical chemistry techniques greatly increased the efficiency and reliability of these methods. These evolved HTE techniques have been utilized extensively to develop highly innovative catalysis solutions to the most challenging problems in large-scale pharmaceutical synthesis. Starting with Pd- and Cu-catalyzed cross-coupling chemistry, subsequent efforts expanded to other valuable modern synthetic transformations such as chiral phase-transfer catalysis, photoredox catalysis, and C-H functionalization. As our experience and confidence in HTE techniques matured, we envisioned their application beyond problems in process chemistry to address the needs of medicinal chemists. Here the problem of reaction generality is felt most acutely, and HTE approaches should prove broadly enabling. However, the quantities of both time and starting materials available for chemistry troubleshooting in this space generally are severely limited. Adapting to these needs led us to invest in smaller predefined arrays of transformation-specific screening "kits" and push the boundaries of miniaturization in chemistry screening, culminating in the development of "nanoscale" reaction screening carried out in 1536-well plates. Grappling with the problem of generality also inspired the exploration of cheminformatics-driven HTE approaches such as the Chemistry Informer Libraries. These next-generation HTE methods promise to empower chemists to run orders of magnitude more experiments and enable "big data" informatics approaches to reaction design and troubleshooting. With these advances, HTE is poised to revolutionize how chemists across both industry and academia discover new synthetic methods, develop them into tools of broad utility, and apply them to problems of practical significance.

A common thermal niche among geographically diverse populations of the widely distributed tree species Eucalyptus tereticornis: No evidence for adaptation to climate-of-origin.

PubMed

Drake, John E; Vårhammar, Angelica; Kumarathunge, Dushan; Medlyn, Belinda E; Pfautsch, Sebastian; Reich, Peter B; Tissue, David T; Ghannoum, Oula; Tjoelker, Mark G

2017-12-01

Impacts of climate warming depend on the degree to which plants are constrained by adaptation to their climate-of-origin or exhibit broad climatic suitability. We grew cool-origin, central and warm-origin provenances of Eucalyptus tereticornis in an array of common temperature environments from 18 to 35.5°C to determine if this widely distributed tree species consists of geographically contrasting provenances with differentiated and narrow thermal niches, or if provenances share a common thermal niche. The temperature responses of photosynthesis, respiration, and growth were equivalent across the three provenances, reflecting a common thermal niche despite a 2,200 km geographic distance and 13°C difference in mean annual temperature at seed origin. The temperature dependence of growth was primarily mediated by changes in leaf area per unit plant mass, photosynthesis, and whole-plant respiration. Thermal acclimation of leaf, stem, and root respiration moderated the increase in respiration with temperature, but acclimation was constrained at high temperatures. We conclude that this species consists of provenances that are not differentiated in their thermal responses, thus rejecting our hypothesis of adaptation to climate-of-origin and suggesting a shared thermal niche. In addition, growth declines with warming above the temperature optima were driven by reductions in whole-plant leaf area and increased respiratory carbon losses. The impacts of climate warming will nonetheless vary across the geographic range of this and other such species, depending primarily on each provenance's climate position on the temperature response curves for photosynthesis, respiration, and growth. © 2017 John Wiley & Sons Ltd.

The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

NASA Technical Reports Server (NTRS)

Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.;

The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

NASA Astrophysics Data System (ADS)

Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Hubmayr, J.; Koopman, B. J.; Lanen, J. V.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Niraula, P.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Ward, J. T.; Wollack, E. J.; Vavagiakis, E. M.

2016-08-01

The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive receiver for the 6-m Atacama Cosmology Telescope (ACT) and measures the small angular scale polarization anisotropies in the cosmic microwave background (CMB). The full focal plane is composed of three detector arrays, containing over 3000 transition edge sensors (TES detectors) in total. The first two detector arrays, observing at 146 GHz, were deployed in 2013 and 2014, respectively. The third and final array is composed of multichroic pixels sensitive to both 90 and 146 GHz and saw first light in February 2015. Fabricated at NIST, this dichroic array consists of 255 pixels, with a total of 1020 polarization sensitive bolometers and is coupled to the telescope with a monolithic array of broad-band silicon feedhorns. The detectors are read out using time-division SQUID multiplexing and cooled by a dilution refrigerator at 110 mK. We present an overview of the assembly and characterization of this multichroic array in the lab, and the initial detector performance in Chile. The detector array has a TES detector electrical yield of 85 %, a total array sensitivity of less than 10 \\upmu K√{ {s}}, and detector time constants and saturation powers suitable for ACT CMB observations.

THE BARYON ACOUSTIC OSCILLATION BROADBAND AND BROAD-BEAM ARRAY: DESIGN OVERVIEW AND SENSITIVITY FORECASTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pober, Jonathan C.; Parsons, Aaron R.; McQuinn, Matthew

2013-03-15

This work describes a new instrument optimized for a detection of the neutral hydrogen 21 cm power spectrum between redshifts of 0.5 and 1.5: the Baryon Acoustic Oscillation Broadband and Broad-beam (BAOBAB) array. BAOBAB will build on the efforts of a first generation of 21 cm experiments that are targeting a detection of the signal from the Epoch of Reionization at z {approx} 10. At z {approx} 1, the emission from neutral hydrogen in self-shielded overdense halos also presents an accessible signal, since the dominant, synchrotron foreground emission is considerably fainter than at redshift 10. The principle science driver formore » these observations are baryon acoustic oscillations in the matter power spectrum which have the potential to act as a standard ruler and constrain the nature of dark energy. BAOBAB will fully correlate dual-polarization antenna tiles over the 600-900 MHz band with a frequency resolution of 300 kHz and a system temperature of 50 K. The number of antennas will grow in staged deployments, and reconfigurations of the array will allow for both traditional imaging and high power spectrum sensitivity operations. We present calculations of the power spectrum sensitivity for various array sizes, with a 35 element array measuring the cosmic neutral hydrogen fraction as a function of redshift, and a 132 element system detecting the BAO features in the power spectrum, yielding a 1.8% error on the z {approx} 1 distance scale, and, in turn, significant improvements to constraints on the dark energy equation of state over an unprecedented range of redshifts from {approx}0.5 to 1.5.« less

Nonlinear estimation for arrays of chemical sensors

NASA Astrophysics Data System (ADS)

Yosinski, Jason; Paffenroth, Randy

2010-04-01

Reliable detection of hazardous materials is a fundamental requirement of any national security program. Such materials can take a wide range of forms including metals, radioisotopes, volatile organic compounds, and biological contaminants. In particular, detection of hazardous materials in highly challenging conditions - such as in cluttered ambient environments, where complex collections of analytes are present, and with sensors lacking specificity for the analytes of interest - is an important part of a robust security infrastructure. Sophisticated single sensor systems provide good specificity for a limited set of analytes but often have cumbersome hardware and environmental requirements. On the other hand, simple, broadly responsive sensors are easily fabricated and efficiently deployed, but such sensors individually have neither the specificity nor the selectivity to address analyte differentiation in challenging environments. However, arrays of broadly responsive sensors can provide much of the sensitivity and selectivity of sophisticated sensors but without the substantial hardware overhead. Unfortunately, arrays of simple sensors are not without their challenges - the selectivity of such arrays can only be realized if the data is first distilled using highly advanced signal processing algorithms. In this paper we will demonstrate how the use of powerful estimation algorithms, based on those commonly used within the target tracking community, can be extended to the chemical detection arena. Herein our focus is on algorithms that not only provide accurate estimates of the mixture of analytes in a sample, but also provide robust measures of ambiguity, such as covariances.

Effective Use of Weigh-in-Motion Data : The Netherlands Case Study

DOT National Transportation Integrated Search

2007-10-01

Transportation and law enforcement agencies in the Netherlands have developed a robust weigh-in-motion (WIM) data management system that supports a broad array of vehicle weight regulation and enforcement activities, as well as long-term planning and...

Everglades Collaborative Adaptive Management Program Progress

EPA Science Inventory

When the Comprehensive Everglades Restoration Plan (CERP) was authorized in 2000, adaptive management (AM) was recognized as a necessary tool to address uncertainty in achieving the broad goals and objectives for restoring a highly managed system. The Everglades covers18,000 squ...

Adaptive Identification by Systolic Arrays.

DTIC Science & Technology

1987-12-01

BIBLIOGRIAPHY Anton , Howard, Elementary Linear Algebra , John Wiley & Sons, 19S4. Cristi, Roberto, A Parallel Structure Jor Adaptive Pole Placement...10 11. SYSTEM IDENTIFICATION M*YETHODS ....................... 12 A. LINEAR SYSTEM MODELING ......................... 12 B. SOLUTION OF SYSTEMS OF... LINEAR EQUATIONS ......... 13 C. QR DECOMPOSITION ................................ 14 D. RECURSIVE LEAST SQUARES ......................... 16 E. BLOCK

Bentho-pelagic divergence of cichlid feeding architecture was prodigious and consistent during multiple adaptive radiations within African rift-lakes.

PubMed

Cooper, W James; Parsons, Kevin; McIntyre, Alyssa; Kern, Brittany; McGee-Moore, Alana; Albertson, R Craig

2010-03-08

How particular changes in functional morphology can repeatedly promote ecological diversification is an active area of evolutionary investigation. The African rift-lake cichlids offer a calibrated time series of the most dramatic adaptive radiations of vertebrate trophic morphology yet described, and the replicate nature of these events provides a unique opportunity to test whether common changes in functional morphology have repeatedly facilitated their ecological success. Specimens from 87 genera of cichlid fishes endemic to Lakes Tanganyka, Malawi and Victoria were dissected in order to examine the functional morphology of cichlid feeding. We quantified shape using geometric morphometrics and compared patterns of morphological diversity using a series of analytical tests. The primary axes of divergence were conserved among all three radiations, and the most prevalent changes involved the size of the preorbital region of the skull. Even the fishes from the youngest of these lakes (Victoria), which exhibit the lowest amount of skull shape disparity, have undergone extensive preorbital evolution relative to other craniofacial traits. Such changes have large effects on feeding biomechanics, and can promote expansion into a wide array of niches along a bentho-pelagic ecomorphological axis. Here we show that specific changes in trophic anatomy have evolved repeatedly in the African rift lakes, and our results suggest that simple morphological alterations that have large ecological consequences are likely to constitute critical components of adaptive radiations in functional morphology. Such shifts may precede more complex shape changes as lineages diversify into unoccupied niches. The data presented here, combined with observations of other fish lineages, suggest that the preorbital region represents an evolutionary module that can respond quickly to natural selection when fishes colonize new lakes. Characterizing the changes in cichlid trophic morphology that have contributed to their extraordinary adaptive radiations has broad evolutionary implications, and such studies are necessary for directing future investigations into the proximate mechanisms that have shaped these spectacular phenomena.

Ultra-broad gain quantum cascade lasers tunable from 6.5 to 10.4 μm.

PubMed

Xie, Feng; Caneau, C; Leblanc, H; Ho, M-T; Zah, C

2015-09-01

We present a quantum cascade laser structure with an ultra-broad gain profile that covers the wavelength range from 6.5 to 10.4 μm. In a grating-tuned external cavity, we demonstrated continuous tuning from 1027  cm(-1) to 1492  cm(-1) with this broad gain laser chip. We also fabricated distributed feedback quantum cascade laser arrays with this active region design and varied grating periods. We demonstrated single wavelength lasing from 962 (10.4) to 1542  cm(-1) (6.5 μm). The frequency coverage (580  cm(-1)) is about 46% of center frequency.

Adaptation of the Biolog Phenotype MicroArrayTM Technology to Profile the Obligate Anaerobe Geobacter metallireducens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joyner, Dominique; Fortney, Julian; Chakraborty, Romy

2010-05-17

The Biolog OmniLog? Phenotype MicroArray (PM) plate technology was successfully adapted to generate a select phenotypic profile of the strict anaerobe Geobacter metallireducens (G.m.). The profile generated for G.m. provides insight into the chemical sensitivity of the organism as well as some of its metabolic capabilities when grown with a basal medium containing acetate and Fe(III). The PM technology was developed for aerobic organisms. The reduction of a tetrazolium dye by the test organism represents metabolic activity on the array which is detected and measured by the OmniLog(R) system. We have previously adapted the technology for the anaerobic sulfate reducingmore » bacterium Desulfovibrio vulgaris. In this work, we have taken the technology a step further by adapting it for the iron reducing obligate anaerobe Geobacter metallireducens. In an osmotic stress microarray it was determined that the organism has higher sensitivity to impermeable solutes 3-6percent KCl and 2-5percent NaNO3 that result in osmotic stress by osmosis to the cell than to permeable non-ionic solutes represented by 5-20percent ethylene glycol and 2-3percent urea. The osmotic stress microarray also includes an array of osmoprotectants and precursor molecules that were screened to identify substrates that would provide osmotic protection to NaCl stress. None of the substrates tested conferred resistance to elevated concentrations of salt. Verification studies in which G.m. was grown in defined medium amended with 100mM NaCl (MIC) and the common osmoprotectants betaine, glycine and proline supported the PM findings. Further verification was done by analysis of transcriptomic profiles of G.m. grown under 100mM NaCl stress that revealed up-regulation of genes related to degradation rather than accumulation of the above-mentioned osmoprotectants. The phenotypic profile, supported by additional analysis indicates that the accumulation of these osmoprotectants as a response to salt stress does not occur in G.m. and response to stress must occur by other mechanisms. The Phenotype MicroArray technology can be reliably used as a rapid screening tool for characterization in anaerobic microbial ecology.« less

Adaptive smart simulator for characterization and MPPT construction of PV array

NASA Astrophysics Data System (ADS)

Ouada, Mehdi; Meridjet, Mohamed Salah; Dib, Djalel

2016-07-01

Partial shading conditions are among the most important problems in large photovoltaic array. Many works of literature are interested in modeling, control and optimization of photovoltaic conversion of solar energy under partial shading conditions, The aim of this study is to build a software simulator similar to hard simulator and to produce a shading pattern of the proposed photovoltaic array in order to use the delivered information to obtain an optimal configuration of the PV array and construct MPPT algorithm. Graphical user interfaces (Matlab GUI) are built using a developed script, this tool is easy to use, simple, and has a rapid of responsiveness, the simulator supports large array simulations that can be interfaced with MPPT and power electronic converters.

Robust Approach for Nonuniformity Correction in Infrared Focal Plane Array.

PubMed

Boutemedjet, Ayoub; Deng, Chenwei; Zhao, Baojun

2016-11-10

In this paper, we propose a new scene-based nonuniformity correction technique for infrared focal plane arrays. Our work is based on the use of two well-known scene-based methods, namely, adaptive and interframe registration-based exploiting pure translation motion model between frames. The two approaches have their benefits and drawbacks, which make them extremely effective in certain conditions and not adapted for others. Following on that, we developed a method robust to various conditions, which may slow or affect the correction process by elaborating a decision criterion that adapts the process to the most effective technique to ensure fast and reliable correction. In addition to that, problems such as bad pixels and ghosting artifacts are also dealt with to enhance the overall quality of the correction. The performance of the proposed technique is investigated and compared to the two state-of-the-art techniques cited above.

Robust Approach for Nonuniformity Correction in Infrared Focal Plane Array

PubMed Central

Boutemedjet, Ayoub; Deng, Chenwei; Zhao, Baojun

2016-01-01

In this paper, we propose a new scene-based nonuniformity correction technique for infrared focal plane arrays. Our work is based on the use of two well-known scene-based methods, namely, adaptive and interframe registration-based exploiting pure translation motion model between frames. The two approaches have their benefits and drawbacks, which make them extremely effective in certain conditions and not adapted for others. Following on that, we developed a method robust to various conditions, which may slow or affect the correction process by elaborating a decision criterion that adapts the process to the most effective technique to ensure fast and reliable correction. In addition to that, problems such as bad pixels and ghosting artifacts are also dealt with to enhance the overall quality of the correction. The performance of the proposed technique is investigated and compared to the two state-of-the-art techniques cited above. PMID:27834893

Adaptive Sparse Representation for Source Localization with Gain/Phase Errors

PubMed Central

Sun, Ke; Liu, Yimin; Meng, Huadong; Wang, Xiqin

2011-01-01

Sparse representation (SR) algorithms can be implemented for high-resolution direction of arrival (DOA) estimation. Additionally, SR can effectively separate the coherent signal sources because the spectrum estimation is based on the optimization technique, such as the L1 norm minimization, but not on subspace orthogonality. However, in the actual source localization scenario, an unknown gain/phase error between the array sensors is inevitable. Due to this nonideal factor, the predefined overcomplete basis mismatches the actual array manifold so that the estimation performance is degraded in SR. In this paper, an adaptive SR algorithm is proposed to improve the robustness with respect to the gain/phase error, where the overcomplete basis is dynamically adjusted using multiple snapshots and the sparse solution is adaptively acquired to match with the actual scenario. The simulation results demonstrate the estimation robustness to the gain/phase error using the proposed method. PMID:22163875

Laser photovoltaic power system synergy for SEI applications

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Hickman, J. M.

1991-01-01

Solar arrays can provide reliable space power, but do not operate when there is no solar energy. Photovoltaic arrays can also convert laser energy with high efficiency. One proposal to reduce the required mass of energy storage required is to illuminate the photovoltaic arrays by a ground laser system. It is proposed to locate large lasers on cloud-free sites at one or more ground locations, and use large lenses or mirrors with adaptive optical correction to reduce the beam spread due to diffraction or atmospheric turbulence. During the eclipse periods or lunar night, the lasers illuminate the solar arrays to a level sufficient to provide operating power.

Hierarchical sinuous-antenna phased array for millimeter wavelengths

NASA Astrophysics Data System (ADS)

Cukierman, Ari; Lee, Adrian T.; Raum, Christopher; Suzuki, Aritoki; Westbrook, Benjamin

2018-03-01

We present the design, fabrication, and measured performance of a hierarchical sinuous-antenna phased array coupled to superconducting transition-edge-sensor (TES) bolometers for millimeter wavelengths. The architecture allows for dual-polarization wideband sensitivity with a beam width that is approximately frequency-independent. We report on measurements of a prototype device, which uses three levels of triangular phased arrays to synthesize beams that are approximately constant in width across three frequency bands covering a 3:1 bandwidth. The array element is a lens-coupled sinuous antenna. The device consists of an array of hemispherical lenses coupled to a lithographed wafer, which integrates TESs, planar sinuous antennas, and microwave circuitry including band-defining filters. The approximately frequency-independent beam widths improve coupling to telescope optics and keep the sensitivity of an experiment close to optimal across a broad frequency range. The design can be straightforwardly modified for use with non-TES lithographed cryogenic detectors such as kinetic inductance detectors. Additionally, we report on the design and measurements of a broadband 180° hybrid that can simplify the design of future multichroic focal planes including but not limited to hierarchical phased arrays.

Low power, lightweight vapor sensing using arrays of conducting polymer composite chemically-sensitive resistors

NASA Technical Reports Server (NTRS)

Ryan, M. A.; Lewis, N. S.

2001-01-01

Arrays of broadly responsive vapor detectors can be used to detect, identify, and quantify vapors and vapor mixtures. One implementation of this strategy involves the use of arrays of chemically-sensitive resistors made from conducting polymer composites. Sorption of an analyte into the polymer composite detector leads to swelling of the film material. The swelling is in turn transduced into a change in electrical resistance because the detector films consist of polymers filled with conducting particles such as carbon black. The differential sorption, and thus differential swelling, of an analyte into each polymer composite in the array produces a unique pattern for each different analyte of interest, Pattern recognition algorithms are then used to analyze the multivariate data arising from the responses of such a detector array. Chiral detector films can provide differential detection of the presence of certain chiral organic vapor analytes. Aspects of the spaceflight qualification and deployment of such a detector array, along with its performance for certain analytes of interest in manned life support applications, are reviewed and summarized in this article.

Location of high-frequency P wave microseismic noise in the Pacific Ocean using multiple small aperture arrays

DOE PAGES

Pyle, Moira L.; Koper, Keith D.; Euler, Garrett G.; ...

2015-04-20

We investigate source locations of P-wave microseisms within a narrow frequency band (0.67–1.33 Hz) that is significantly higher than the classic microseism band (~0.05–0.3 Hz). Employing a backprojection method, we analyze data recorded during January 2010 from five International Monitoring System arrays that border the Pacific Ocean. We develop a ranking scheme that allows us to combine beam power from multiple arrays to obtain robust locations of the microseisms. Some individual arrays exhibit a strong regional component, but results from the combination of all arrays show high-frequency P wave energy emanating from the North Pacific basin, in general agreement withmore » previous observations in the double-frequency (DF) microseism band (~0.1–0.3 Hz). This suggests that the North Pacific source of ambient P noise covers a broad range of frequencies and that the wave-wave interaction model is likely valid at shorter periods.« less

Multiple adaptable mechanisms early in the primate visual pathway

PubMed Central

Dhruv, Neel T.; Tailby, Chris; Sokol, Sach H.; Lennie, Peter

2011-01-01

We describe experiments that isolate and characterize multiple adaptable mechanisms that influence responses of orientation-selective neurons in primary visual cortex (V1) of anesthetized macaque (Macaca fascicularis). The results suggest that three adaptable stages of machinery shape neural responses in V1: a broadly-tuned early stage and a spatio-temporally tuned later stage, both of which provide excitatory input, and a normalization pool that is also broadly tuned. The early stage and the normalization pool are revealed by adapting gratings that themselves fail to evoke a response from the neuron: either low temporal frequency gratings at the null orientation or gratings of any orientation drifting at high temporal frequencies. When effective, adapting stimuli that altered the sensitivity of these two mechanisms caused reductions of contrast gain and often brought about a paradoxical increase in response gain due to a relatively greater desensitization of the normalization pool. The tuned mechanism is desensitized only by stimuli well-matched to a neuron’s receptive field. We could thus infer desensitization of the tuned mechanism by comparing effects obtained with adapting gratings of preferred and null orientation modulated at low temporal frequencies. PMID:22016535

Performance analysis of structured gradient algorithm. [for adaptive beamforming linear arrays

NASA Technical Reports Server (NTRS)

Godara, Lal C.

1990-01-01

The structured gradient algorithm uses a structured estimate of the array correlation matrix (ACM) to estimate the gradient required for the constrained least-mean-square (LMS) algorithm. This structure reflects the structure of the exact array correlation matrix for an equispaced linear array and is obtained by spatial averaging of the elements of the noisy correlation matrix. In its standard form the LMS algorithm does not exploit the structure of the array correlation matrix. The gradient is estimated by multiplying the array output with the receiver outputs. An analysis of the two algorithms is presented to show that the covariance of the gradient estimated by the structured method is less sensitive to the look direction signal than that estimated by the standard method. The effect of the number of elements on the signal sensitivity of the two algorithms is studied.

Intercepted signals for ionospheric science

NASA Astrophysics Data System (ADS)

Lind, F. D.; Erickson, P. J.; Coster, A. J.; Foster, J. C.; Marchese, J. R.; Berkowitz, Z.; Sahr, J. D.

2013-05-01

The ISIS array (Intercepted Signals for Ionospheric Science) is a distributed, coherent software radio array designed for the study of geospace phenomena by observing the scatter of ambient radio frequency (RF) signals. ISIS data acquisition and analysis is performed using the MIDAS-M platform (Millstone Data Acquisition System - Mobile). Observations of RF signals can be performed between HF and L-band using the Array nodes and appropriate antennas. The deployment of the Array focuses on observations of the plasmasphere boundary layer. We discuss the concept of the coherent software radio array, describe the ISIS hardware, and give examples of data from the system for selected applications. In particular, we include the first observations of E region irregularities using the Array. We also present single-site passive radar observations of both meteor trails and E region irregularities using adaptive filtering techniques.

Insect Repellents: Modulators of mosquito odorant receptor activity

USDA-ARS?s Scientific Manuscript database

Mosquitoes vector numerous pathogens that cause diseases including malaria, yellow fever, dengue fever and chikungunya. DEET, IR3535, Picaridin and 2-undecanone are insect repellents that are used to prevent interactions between humans and a broad array of disease vectors including mosquitoes. While...

Degradability of an Acrylate-Linked, Fluorotelomer Polymer in Soil

EPA Science Inventory

Fluorotelomer polymers are used in a broad array of products in modern societies worldwide and, if they degrade at significant rates, potentially are a significant source of perfluorooctanoic acid (PFOA) and related compounds to the environment. To evaluate this possibility, we i...

Public supports traffic safety laws and their active enforcement

DOT National Transportation Integrated Search

1996-09-01

According to the results of a recent national telephone survey, the public strongly supports a broad array of traffic safety laws. More than 8,000 people in all 50 states and the District of Columbia participated in a national telephone survey conduc...

Phased Array Mirror Extendible Large Aperture (PAMELA) Optics Adjustment

NASA Technical Reports Server (NTRS)

1995-01-01

Scientists at Marshall's Adaptive Optics Lab demonstrate the Wave Front Sensor alignment using the Phased Array Mirror Extendible Large Aperture (PAMELA) optics adjustment. The primary objective of the PAMELA project is to develop methods for aligning and controlling adaptive optics segmented mirror systems. These systems can be used to acquire or project light energy. The Next Generation Space Telescope is an example of an energy acquisition system that will employ segmented mirrors. Light projection systems can also be used for power beaming and orbital debris removal. All segmented optical systems must be adjusted to provide maximum performance. PAMELA is an on going project that NASA is utilizing to investigate various methods for maximizing system performance.

A mixed-signal implementation of a polychronous spiking neural network with delay adaptation

PubMed Central

Wang, Runchun M.; Hamilton, Tara J.; Tapson, Jonathan C.; van Schaik, André

2014-01-01

We present a mixed-signal implementation of a re-configurable polychronous spiking neural network capable of storing and recalling spatio-temporal patterns. The proposed neural network contains one neuron array and one axon array. Spike Timing Dependent Delay Plasticity is used to fine-tune delays and add dynamics to the network. In our mixed-signal implementation, the neurons and axons have been implemented as both analog and digital circuits. The system thus consists of one FPGA, containing the digital neuron array and the digital axon array, and one analog IC containing the analog neuron array and the analog axon array. The system can be easily configured to use different combinations of each. We present and discuss the experimental results of all combinations of the analog and digital axon arrays and the analog and digital neuron arrays. The test results show that the proposed neural network is capable of successfully recalling more than 85% of stored patterns using both analog and digital circuits. PMID:24672422

A mixed-signal implementation of a polychronous spiking neural network with delay adaptation.

PubMed

Wang, Runchun M; Hamilton, Tara J; Tapson, Jonathan C; van Schaik, André

2014-01-01

We present a mixed-signal implementation of a re-configurable polychronous spiking neural network capable of storing and recalling spatio-temporal patterns. The proposed neural network contains one neuron array and one axon array. Spike Timing Dependent Delay Plasticity is used to fine-tune delays and add dynamics to the network. In our mixed-signal implementation, the neurons and axons have been implemented as both analog and digital circuits. The system thus consists of one FPGA, containing the digital neuron array and the digital axon array, and one analog IC containing the analog neuron array and the analog axon array. The system can be easily configured to use different combinations of each. We present and discuss the experimental results of all combinations of the analog and digital axon arrays and the analog and digital neuron arrays. The test results show that the proposed neural network is capable of successfully recalling more than 85% of stored patterns using both analog and digital circuits.

Multicolor photonic crystal laser array

DOEpatents

Wright, Jeremy B; Brener, Igal; Subramania, Ganapathi S; Wang, George T; Li, Qiming

2015-04-28

A multicolor photonic crystal laser array comprises pixels of monolithically grown gain sections each with a different emission center wavelength. As an example, two-dimensional surface-emitting photonic crystal lasers comprising broad gain-bandwidth III-nitride multiple quantum well axial heterostructures were fabricated using a novel top-down nanowire fabrication method. Single-mode lasing was obtained in the blue-violet spectral region with 60 nm of tuning (or 16% of the nominal center wavelength) that was determined purely by the photonic crystal geometry. This approach can be extended to cover the entire visible spectrum.

A Broad-Band Array of Aperture-Coupled Cavity-Backed Slot Elements

DTIC Science & Technology

1988-01-01

RPOR NUM3ER2. GOVT ACCESSION HO. 3. RECIPIENT’S CATALOG NUMBER 4. TITLE (and Subtitle) S. TYPE OF REPORT 6 PERIOD COVERED A, 1(A--BND iP ,LUPY 09...Repor t AUG 0 4 988SAME AS REPORT 1SUPPL-EMENTARY NOTES LYNNve E. r WOLAVERlease:j) IAW AFR 190-1 Dean for Research an4’Prot e-ssional Develomn Air Force...previous CBS arrays: aperture coupling, and ’half-width’ cavities. Expiremental results demonstrated these departures enhance the po- tential for larger

Fabrication of nanopore and nanoparticle arrays with high aspect ratio AAO masks.

PubMed

Li, Z P; Xu, Z M; Qu, X P; Wang, S B; Peng, J; Mei, L H

2017-03-03

How to use high aspect ratio anodic aluminum oxide (AAO) membranes as an etching and evaporation mask is one of the unsolved problems in the application of nanostructured arrays. Here we describe the versatile utilizations of the highly ordered AAO membranes with a high aspect ratio of more than 20 used as universal masks for the formation of various nanostructure arrays on various substrates. The result shows that the fabricated nanopore and nanoparticle arrays of substrates inherit the regularity of the AAO membranes completely. The flat AAO substrates and uneven AAO frontages were attached to the Si substrates respectively as an etching mask, which demonstrates that the two kinds of replication, positive and negative, represent the replication of the mirroring of Si substrates relative to the flat AAO substrates and uneven AAO frontages. Our work is a breakthrough for the broad research field of surface nano-masking.

Fabrication of nanopore and nanoparticle arrays with high aspect ratio AAO masks

NASA Astrophysics Data System (ADS)

Li, Z. P.; Xu, Z. M.; Qu, X. P.; Wang, S. B.; Peng, J.; Mei, L. H.

2017-03-01

How to use high aspect ratio anodic aluminum oxide (AAO) membranes as an etching and evaporation mask is one of the unsolved problems in the application of nanostructured arrays. Here we describe the versatile utilizations of the highly ordered AAO membranes with a high aspect ratio of more than 20 used as universal masks for the formation of various nanostructure arrays on various substrates. The result shows that the fabricated nanopore and nanoparticle arrays of substrates inherit the regularity of the AAO membranes completely. The flat AAO substrates and uneven AAO frontages were attached to the Si substrates respectively as an etching mask, which demonstrates that the two kinds of replication, positive and negative, represent the replication of the mirroring of Si substrates relative to the flat AAO substrates and uneven AAO frontages. Our work is a breakthrough for the broad research field of surface nano-masking.

Multiband selection with linear array detectors

NASA Technical Reports Server (NTRS)

Richard, H. L.; Barnes, W. L.

1985-01-01

Several techniques that can be used in an earth-imaging system to separate the linear image formed after the collecting optics into the desired spectral band are examined. The advantages and disadvantages of the Multispectral Linear Array (MLA) multiple optics, the MLA adjacent arrays, the imaging spectrometer, and the MLA beam splitter are discussed. The beam-splitter design approach utilizes, in addition to relatively broad spectral region separation, a movable Multiband Selection Device (MSD), placed between the exit ports of the beam splitter and a linear array detector, permitting many bands to be selected. The successful development and test of the MSD is described. The device demonstrated the capacity to provide a wide field of view, visible-to-near IR/short-wave IR and thermal IR capability, and a multiplicity of spectral bands and polarization measuring means, as well as a reasonable size and weight at minimal cost and risk compared to a spectrometer design approach.

Golden Gate Assembly of CRISPR gRNA expression array for simultaneously targeting multiple genes.

PubMed

Vad-Nielsen, Johan; Lin, Lin; Bolund, Lars; Nielsen, Anders Lade; Luo, Yonglun

2016-11-01

The engineered CRISPR/Cas9 technology has developed as the most efficient and broadly used genome editing tool. However, simultaneously targeting multiple genes (or genomic loci) in the same individual cells using CRISPR/Cas9 remain one technical challenge. In this article, we have developed a Golden Gate Assembly method for the generation of CRISPR gRNA expression arrays, thus enabling simultaneous gene targeting. Using this method, the generation of CRISPR gRNA expression array can be accomplished in 2 weeks, and contains up to 30 gRNA expression cassettes. We demonstrated in the study that simultaneously targeting 10 genomic loci or simultaneously inhibition of multiple endogenous genes could be achieved using the multiplexed gRNA expression array vector in human cells. The complete set of plasmids is available through the non-profit plasmid repository Addgene.

Characterizing SH2 Domain Specificity and Network Interactions Using SPOT Peptide Arrays.

PubMed

Liu, Bernard A

2017-01-01

Src Homology 2 (SH2) domains are protein interaction modules that recognize and bind tyrosine phosphorylated ligands. Their ability to distinguish binding to over thousands of potential phosphotyrosine (pTyr) ligands within the cell is critical for the fidelity of receptor tyrosine kinase (RTK) signaling. Within humans there are over a hundred SH2 domains with more than several thousand potential ligands across many cell types and cell states. Therefore, defining the specificity of individual SH2 domains is critical for predicting and identifying their physiological ligands. Here, in this chapter, I describe the broad use of SPOT peptide arrays for examining SH2 domain specificity. An orientated peptide array library (OPAL) approach can uncover both favorable and non-favorable residues, thus providing an in-depth analysis to SH2 specificity. Moreover, I discuss the application of SPOT arrays for paneling SH2 ligand binding with physiological peptides.

History-dependent dissipative vortex dynamics in superconducting arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durkin, Malcolm; Mondragon-Shem, Ian; Eley, Serena Merteen

In this study, we perform current (I)-voltage (V) measurements on low resistance superconductor-normal-superconductor arrays in finite magnetic fields, focusing on the dilute vortex population regime. We observe significant deviations from predicted behavior, notably the absence of a differential resistance peak near the vortex depinning current, and a broad linear I-V region with an extrapolated I intercept equal to the depinning current. Comparing these results to an overdamped molecular vortex model, we find that this behavior can be explained by the presence of a history-dependent dissipative force. Lastly, this approach has not been considered previously, to our knowledge, yet it ismore » crucial for obtaining a correct description of the vortex dynamics in superconducting arrays.« less

History-dependent dissipative vortex dynamics in superconducting arrays

DOE PAGES

Durkin, Malcolm; Mondragon-Shem, Ian; Eley, Serena Merteen; ...

2016-07-14

In this study, we perform current (I)-voltage (V) measurements on low resistance superconductor-normal-superconductor arrays in finite magnetic fields, focusing on the dilute vortex population regime. We observe significant deviations from predicted behavior, notably the absence of a differential resistance peak near the vortex depinning current, and a broad linear I-V region with an extrapolated I intercept equal to the depinning current. Comparing these results to an overdamped molecular vortex model, we find that this behavior can be explained by the presence of a history-dependent dissipative force. Lastly, this approach has not been considered previously, to our knowledge, yet it ismore » crucial for obtaining a correct description of the vortex dynamics in superconducting arrays.« less

Synthesis and photoluminescence properties of ZnS nanobowl arrays via colloidal monolayer template

PubMed Central

2014-01-01

Two-dimensional Zinc sulfide (ZnS) nanobowl arrays were synthesized via self-assembled monolayer polystyrene sphere template floating on precursor solution surface. A facile approach was proposed to investigate the morphology evolution of nanobowl arrays by post-annealing procedure. Photoluminescence (PL) measurement of as-grown nanoarrays shows that the spectrum mainly includes two parts: a purple emission peak at 382 nm and a broad blue emission band centering at 410 nm with a shoulder around 459 nm, and a blue emission band at 440 nm was obtained after the annealing procedure. ZnS nanoarrays with special morphologies and PL emission are benefits to their promising application in novel photoluminescence nanodevice. PMID:25246857

A High-Efficiency Si Nanowire Array/Perovskite Hybrid Solar Cell.

PubMed

Yan, Xin; Zhang, Chen; Wang, Jiamin; Zhang, Xia; Ren, Xiaomin

2017-12-01

A low-cost Si nanowire array/perovskite hybrid solar cell is proposed and simulated. The solar cell consists of a Si p-i-n nanowire array filled with CH 3 NH 3 PbI 3 , in which both the nanowires and perovskite absorb the incident light while the nanowires act as the channels for transporting photo-generated electrons and holes. The hybrid structure has a high absorption efficiency in a broad wavelength range of 300~800 nm. A large short-circuit current density of 28.8 mA/cm 2 and remarkable conversion efficiency of 13.3% are obtained at a thin absorber thickness of 1.6 μm, which are comparable to the best results of III-V nanowire solar cells.

Adaptive Noise Reduction Techniques for Airborne Acoustic Sensors

DTIC Science & Technology

2012-01-01

and Preamplifiers . . . . . . . . . . . . . . . . . . . . 16 3.3.2 Audio Recorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 iv 4...consuming less energy than active systems such as radar, lidar, or sonar [5]. Ground and marine-based acoustic arrays are currently employed in a variety of...factors for the performance of an airborne acoustic array. 3.3.1 Audio Microphones and Preamplifiers An audio microphone is a transducer that converts

Analysis of modified SMI method for adaptive array weight control

NASA Technical Reports Server (NTRS)

Dilsavor, R. L.; Moses, R. L.

1989-01-01

An adaptive array is applied to the problem of receiving a desired signal in the presence of weak interference signals which need to be suppressed. A modification, suggested by Gupta, of the sample matrix inversion (SMI) algorithm controls the array weights. In the modified SMI algorithm, interference suppression is increased by subtracting a fraction F of the noise power from the diagonal elements of the estimated covariance matrix. Given the true covariance matrix and the desired signal direction, the modified algorithm is shown to maximize a well-defined, intuitive output power ratio criterion. Expressions are derived for the expected value and variance of the array weights and output powers as a function of the fraction F and the number of snapshots used in the covariance matrix estimate. These expressions are compared with computer simulation and good agreement is found. A trade-off is found to exist between the desired level of interference suppression and the number of snapshots required in order to achieve that level with some certainty. The removal of noise eigenvectors from the covariance matrix inverse is also discussed with respect to this application. Finally, the type and severity of errors which occur in the covariance matrix estimate are characterized through simulation.

New perspective on single-radiator multiple-port antennas for adaptive beamforming applications

PubMed Central

Choo, Hosung

2017-01-01

One of the most challenging problems in recent antenna engineering fields is to achieve highly reliable beamforming capabilities in an extremely restricted space of small handheld devices. In this paper, we introduce a new perspective on single-radiator multiple-port (SRMP) antenna to alter the traditional approach of multiple-antenna arrays for improving beamforming performances with reduced aperture sizes. The major contribution of this paper is to demonstrate the beamforming capability of the SRMP antenna for use as an extremely miniaturized front-end component in more sophisticated beamforming applications. To examine the beamforming capability, the radiation properties and the array factor of the SRMP antenna are theoretically formulated for electromagnetic characterization and are used as complex weights to form adaptive array patterns. Then, its fundamental performance limits are rigorously explored through enumerative studies by varying the dielectric constant of the substrate, and field tests are conducted using a beamforming hardware to confirm the feasibility. The results demonstrate that the new perspective of the SRMP antenna allows for improved beamforming performances with the ability of maintaining consistently smaller aperture sizes compared to the traditional multiple-antenna arrays. PMID:29023493

Practical guidelines for implementing adaptive optics in fluorescence microscopy

NASA Astrophysics Data System (ADS)

Wilding, Dean; Pozzi, Paolo; Soloviev, Oleg; Vdovin, Gleb; Verhaegen, Michel

2018-02-01

In life sciences, interest in the microscopic imaging of increasingly complex three dimensional samples, such as cell spheroids, zebrafish embryos, and in vivo applications in small animals, is growing quickly. Due to the increasing complexity of samples, more and more life scientists are considering the implementation of adaptive optics in their experimental setups. While several approaches to adaptive optics in microscopy have been reported, it is often difficult and confusing for the microscopist to choose from the array of techniques and equipment. In this poster presentation we offer a small guide to adaptive optics providing general guidelines for successful adaptive optics implementation.

Multi-element array signal reconstruction with adaptive least-squares algorithms

NASA Technical Reports Server (NTRS)

Kumar, R.

1992-01-01

Two versions of the adaptive least-squares algorithm are presented for combining signals from multiple feeds placed in the focal plane of a mechanical antenna whose reflector surface is distorted due to various deformations. Coherent signal combining techniques based on the adaptive least-squares algorithm are examined for nearly optimally and adaptively combining the outputs of the feeds. The performance of the two versions is evaluated by simulations. It is demonstrated for the example considered that both of the adaptive least-squares algorithms are capable of offsetting most of the loss in the antenna gain incurred due to reflector surface deformations.

DISENTANGLING THE CIRCUMNUCLEAR ENVIRONS OF CENTAURUS A. II. ON THE NATURE OF THE BROAD ABSORPTION LINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Espada, D.; Matsushita, S.; Sakamoto, K.

2010-09-01

We report on atomic gas (H I) and molecular gas (as traced by CO(2-1)) redshifted absorption features toward the nuclear regions of the closest powerful radio galaxy, Centaurus A (NGC 5128). Our H I observations using the Very Long Baseline Array allow us to discern with unprecedented sub-parsec resolution H I absorption profiles toward different positions along the 21 cm continuum jet in the inner 0.''3 (or 5.4 pc). In addition, our CO(2-1) data obtained with the Submillimeter Array probe the bulk of the absorbing molecular gas with little contamination by emission, which was not possible with previous CO single-dishmore » observations. We shed light on the physical properties of the gas in the line of sight with these data, emphasizing the still open debate about the nature of the gas that produces the broad absorption line ({approx}55 km s{sup -1}). First, the broad H I line is more prominent toward the central and brightest 21 cm continuum component than toward a region along the jet at a distance {approx}20 mas (or 0.4 pc) further from the nucleus. This indicates that the broad absorption line arises from gas located close to the nucleus, rather than from diffuse and more distant gas. Second, the different velocity components detected in the CO(2-1) absorption spectrum match well with other molecular lines, such as those of HCO{sup +}(1-0), except the broad absorption line that is detected in HCO{sup +}(1-0) (and most likely related to that of the H I). Dissociation of molecular hydrogen due to the active galactic nucleus seems to be efficient at distances r {approx}< 10 pc, which might contribute to the depth of the broad H I and molecular lines.« less

Thermal adaptation of net ecosystem exchange

USDA-ARS?s Scientific Manuscript database

Thermal adaptation of gross primary production and ecosystem respiration has been well documented over broad thermal gradients. However, no study has examined their interaction as a function of temperature, i.e. the thermal responses of net ecosystem exchange of carbon (NEE). In this study, we const...

Cluster formation by allelomimesis in real-world complex adaptive systems

NASA Astrophysics Data System (ADS)

Juanico, Dranreb Earl; Monterola, Christopher; Saloma, Caesar

2005-04-01

Animal and human clusters are complex adaptive systems and many organize in cluster sizes s that obey the frequency distribution D(s)∝s-τ . The exponent τ describes the relative abundance of the cluster sizes in a given system. Data analyses reveal that real-world clusters exhibit a broad spectrum of τ values, 0.7 (tuna fish schools) ⩽τ⩽4.61 (T4 bacteriophage gene family sizes). Allelomimesis is proposed as an underlying mechanism for adaptation that explains the observed broad τ spectrum. Allelomimesis is the tendency of an individual to imitate the actions of others and two cluster systems have different τ values when their component agents display unequal degrees of allelomimetic tendencies. Cluster formation by allelomimesis is shown to be of three general types: namely, blind copying, information-use copying, and noncopying. Allelomimetic adaptation also reveals that the most stable cluster size is formed by three strongly allelomimetic individuals. Our finding is consistent with available field data taken from killer whales and marmots.

Continental cichlid radiations: functional diversity reveals the role of changing ecological opportunity in the Neotropics.

PubMed

Arbour, Jessica Hilary; López-Fernández, Hernán

2016-08-17

Adaptive radiations have been hypothesized to contribute broadly to the diversity of organisms. Models of adaptive radiation predict that ecological opportunity and ecological release, the availability of empty ecological niches and the response by adapting lineages to occupy them, respectively, drive patterns of phenotypic and lineage diversification. Adaptive radiations driven by 'ecological opportunity' are well established in island systems; it is less clear if ecological opportunity influences continent-wide diversification. We use Neotropical cichlid fishes to test if variation in rates of functional evolution is consistent with changing ecological opportunity. Across a functional morphological axis associated with ram-suction feeding traits, evolutionary rates declined through time as lineages diversified in South America. Evolutionary rates of ram-suction functional morphology also appear to have accelerated as cichlids colonized Central America and encountered renewed opportunity. Our results suggest that ecological opportunity may play an important role in shaping patterns of morphological diversity of even broadly distributed lineages like Neotropical cichlids. © 2016 The Author(s).

Continental cichlid radiations: functional diversity reveals the role of changing ecological opportunity in the Neotropics

PubMed Central

López-Fernández, Hernán

2016-01-01

Adaptive radiations have been hypothesized to contribute broadly to the diversity of organisms. Models of adaptive radiation predict that ecological opportunity and ecological release, the availability of empty ecological niches and the response by adapting lineages to occupy them, respectively, drive patterns of phenotypic and lineage diversification. Adaptive radiations driven by ‘ecological opportunity’ are well established in island systems; it is less clear if ecological opportunity influences continent-wide diversification. We use Neotropical cichlid fishes to test if variation in rates of functional evolution is consistent with changing ecological opportunity. Across a functional morphological axis associated with ram–suction feeding traits, evolutionary rates declined through time as lineages diversified in South America. Evolutionary rates of ram–suction functional morphology also appear to have accelerated as cichlids colonized Central America and encountered renewed opportunity. Our results suggest that ecological opportunity may play an important role in shaping patterns of morphological diversity of even broadly distributed lineages like Neotropical cichlids. PMID:27512144

Compliant tactile sensor that delivers a force vector

NASA Technical Reports Server (NTRS)

Torres-Jara, Eduardo (Inventor)

2010-01-01

Tactile Sensor. The sensor includes a compliant convex surface disposed above a sensor array, the sensor array adapted to respond to deformation of the convex surface to generate a signal related to an applied force vector. The applied force vector has three components to establish the direction and magnitude of an applied force. The compliant convex surface defines a dome with a hollow interior and has a linear relation between displacement and load including a magnet disposed substantially at the center of the dome above a sensor array that responds to magnetic field intensity.

Emergence of antibiotic-resistant extremophiles (AREs).

PubMed

Gabani, Prashant; Prakash, Dhan; Singh, Om V

2012-09-01

Excessive use of antibiotics in recent years has produced bacteria that are resistant to a wide array of antibiotics. Several genetic and non-genetic elements allow microorganisms to adapt and thrive under harsh environmental conditions such as lethal doses of antibiotics. We attempt to classify these microorganisms as antibiotic-resistant extremophiles (AREs). AREs develop strategies to gain greater resistance to antibiotics via accumulation of multiple genes or plasmids that harbor genes for multiple drug resistance (MDR). In addition to their altered expression of multiple genes, AREs also survive by producing enzymes such as penicillinase that inactivate antibiotics. It is of interest to identify the underlying molecular mechanisms by which the AREs are able to survive in the presence of wide arrays of high-dosage antibiotics. Technologically, "omics"-based approaches such as genomics have revealed a wide array of genes differentially expressed in AREs. Proteomics studies with 2DE, MALDI-TOF, and MS/MS have identified specific proteins, enzymes, and pumps that function in the adaptation mechanisms of AREs. This article discusses the molecular mechanisms by which microorganisms develop into AREs and how "omics" approaches can identify the genetic elements of these adaptation mechanisms. These objectives will assist the development of strategies and potential therapeutics to treat outbreaks of pathogenic microorganisms in the future.

Broadband and Wide Field-of-view Plasmonic Metasurface-enabled Waveplates

PubMed Central

Jiang, Zhi Hao; Lin, Lan; Ma, Ding; Yun, Seokho; Werner, Douglas H.; Liu, Zhiwen; Mayer, Theresa S.

2014-01-01

Quasi two-dimensional metasurfaces composed of subwavelength nanoresonator arrays can dramatically alter the properties of light in an ultra-thin planar geometry, enabling new optical functions such as anomalous reflection and refraction, polarization filtering, and wavefront modulation. However, previous metasurface-based nanostructures suffer from low efficiency, narrow bandwidth and/or limited field-of-view due to their operation near the plasmonic resonance. Here we demonstrate plasmonic metasurface-based nanostructures for high-efficiency, angle-insensitive polarization transformation over a broad octave-spanning bandwidth. The structures are realized by optimizing the anisotropic response of an array of strongly coupled nanorod resonators to tailor the interference of light at the subwavelength scale. Nanofabricated reflective half-wave and quarter-wave plates designed using this approach have measured polarization conversion ratios and reflection magnitudes greater than 92% over a broad wavelength range from 640 to 1290 nm and a wide field-of-view up to ±40°. This work outlines a versatile strategy to create metasurface-based photonics with diverse optical functionalities. PMID:25524830

Working Group Report: Sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artuso, M.; et al.,

Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In additionmore » the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.« less

Sensor Compendium - A Snowmass Whitepaper-

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artuso, M.; Battaglia, M.; Bolla, G.

Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In additionmore » the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.« less

Adaptive Wiener filter super-resolution of color filter array images.

PubMed

Karch, Barry K; Hardie, Russell C

2013-08-12

Digital color cameras using a single detector array with a Bayer color filter array (CFA) require interpolation or demosaicing to estimate missing color information and provide full-color images. However, demosaicing does not specifically address fundamental undersampling and aliasing inherent in typical camera designs. Fast non-uniform interpolation based super-resolution (SR) is an attractive approach to reduce or eliminate aliasing and its relatively low computational load is amenable to real-time applications. The adaptive Wiener filter (AWF) SR algorithm was initially developed for grayscale imaging and has not previously been applied to color SR demosaicing. Here, we develop a novel fast SR method for CFA cameras that is based on the AWF SR algorithm and uses global channel-to-channel statistical models. We apply this new method as a stand-alone algorithm and also as an initialization image for a variational SR algorithm. This paper presents the theoretical development of the color AWF SR approach and applies it in performance comparisons to other SR techniques for both simulated and real data.

Correlation processing for correction of phase distortions in subaperture imaging.

PubMed

Tavh, B; Karaman, M

1999-01-01

Ultrasonic subaperture imaging combines synthetic aperture and phased array approaches and permits low-cost systems with improved image quality. In subaperture processing, a large array is synthesized using echo signals collected from a number of receive subapertures by multiple firings of a phased transmit subaperture. Tissue inhomogeneities and displacements in subaperture imaging may cause significant phase distortions on received echo signals. Correlation processing on reference echo signals can be used for correction of the phase distortions, for which the accuracy and robustness are critically limited by the signal correlation. In this study, we explore correlation processing techniques for adaptive subaperture imaging with phase correction for motion and tissue inhomogeneities. The proposed techniques use new subaperture data acquisition schemes to produce reference signal sets with improved signal correlation. The experimental test results were obtained using raw radio frequency (RF) data acquired from two different phantoms with 3.5 MHz, 128-element transducer array. The results show that phase distortions can effectively be compensated by the proposed techniques in real-time adaptive subaperture imaging.

Adaptive Detector Arrays for Optical Communications Receivers

NASA Technical Reports Server (NTRS)

Vilnrotter, V.; Srinivasan, M.

2000-01-01

The structure of an optimal adaptive array receiver for ground-based optical communications is described and its performance investigated. Kolmogorov phase screen simulations are used to model the sample functions of the focal-plane signal distribution due to turbulence and to generate realistic spatial distributions of the received optical field. This novel array detector concept reduces interference from background radiation by effectively assigning higher confidence levels at each instant of time to those detector elements that contain significant signal energy and suppressing those that do not. A simpler suboptimum structure that replaces the continuous weighting function of the optimal receiver by a hard decision on the selection of the signal detector elements also is described and evaluated. Approximations and bounds to the error probability are derived and compared with the exact calculations and receiver simulation results. It is shown that, for photon-counting receivers observing Poisson-distributed signals, performance improvements of approximately 5 dB can be obtained over conventional single-detector photon-counting receivers, when operating in high background environments.

Quantifying the similarity of seismic polarizations

NASA Astrophysics Data System (ADS)

Jones, Joshua P.; Eaton, David W.; Caffagni, Enrico

2016-02-01

Assessing the similarities of seismic attributes can help identify tremor, low signal-to-noise (S/N) signals and converted or reflected phases, in addition to diagnosing site noise and sensor misalignment in arrays. Polarization analysis is a widely accepted method for studying the orientation and directional characteristics of seismic phases via computed attributes, but similarity is ordinarily discussed using qualitative comparisons with reference values or known seismic sources. Here we introduce a technique for quantitative polarization similarity that uses weighted histograms computed in short, overlapping time windows, drawing on methods adapted from the image processing and computer vision literature. Our method accounts for ambiguity in azimuth and incidence angle and variations in S/N ratio. Measuring polarization similarity allows easy identification of site noise and sensor misalignment and can help identify coherent noise and emergent or low S/N phase arrivals. Dissimilar azimuths during phase arrivals indicate misaligned horizontal components, dissimilar incidence angles during phase arrivals indicate misaligned vertical components and dissimilar linear polarization may indicate a secondary noise source. Using records of the Mw = 8.3 Sea of Okhotsk earthquake, from Canadian National Seismic Network broad-band sensors in British Columbia and Yukon Territory, Canada, and a vertical borehole array at Hoadley gas field, central Alberta, Canada, we demonstrate that our method is robust to station spacing. Discrete wavelet analysis extends polarization similarity to the time-frequency domain in a straightforward way. Time-frequency polarization similarities of borehole data suggest that a coherent noise source may have persisted above 8 Hz several months after peak resource extraction from a `flowback' type hydraulic fracture.

Optical design of MEMS-based infrared multi-object spectrograph concept for the Gemini South Telescope

NASA Astrophysics Data System (ADS)

Chen, Shaojie; Sivanandam, Suresh; Moon, Dae-Sik

2016-08-01

We discuss the optical design of an infrared multi-object spectrograph (MOS) concept that is designed to take advantage of the multi-conjugate adaptive optics (MCAO) corrected field at the Gemini South telescope. This design employs a unique, cryogenic MEMS-based focal plane mask to select target objects for spectroscopy by utilizing the Micro-Shutter Array (MSA) technology originally developed for the Near Infrared Spectrometer (NIRSpec) of the James Webb Space Telescope (JWST). The optical design is based on all spherical refractive optics, which serves both imaging and spectroscopic modes across the wavelength range of 0.9-2.5 μm. The optical system consists of a reimaging system, MSA, collimator, volume phase holographic (VPH) grisms, and spectrograph camera optics. The VPH grisms, which are VPH gratings sandwiched between two prisms, provide high dispersing efficiencies, and a set of several VPH grisms provide the broad spectral coverage at high throughputs. The imaging mode is implemented by removing the MSA and the dispersing unit out of the beam. We optimize both the imaging and spectrographic modes simultaneously, while paying special attention to the performance of the pupil imaging at the cold stop. Our current design provides a 1' ♢ 1' and a 0.5' ♢ 1' field of views for imaging and spectroscopic modes, respectively, on a 2048 × 2048 pixel HAWAII-2RG detector array. The spectrograph's slit width and spectral resolving power are 0.18'' and 3,000, respectively, and spectra of up to 100 objects can be obtained simultaneously. We present the overall results of simulated performance using optical model we designed.

New insights on the Gibraltar Arc geodynamics from SKS splitting: first contribution from the IberArray broad-band seismic network

NASA Astrophysics Data System (ADS)

Diaz Cusí, Jordi; Gallart, Josep; Villaseñor, Antonio

2010-05-01

The Rif-Betic region, comprising the Gibraltar Arc and the extensional Alboran basin and including the diffuse limit between the Eurasia and African plates, is complex and there is still not a commonly accepted hypothesis about the mechanism responsible for its formation, as models including lithospheric delamination, convective removal or subduction have been proposed. In this context, the knowledge about the presence and properties of upper mantle anisotropy from SKS splitting measurements can provide valuable information to constrain the different geodynamical models. The installation of new permanent and semi-permanent broadband stations in the region has allowed obtaining a first insight into the anisotropic properties (Buontempo et al, 2008) and evidenced the presence of geographical variations in the anisotropic parameters, even if the lack of data in the Northern part of Morocco did not allow to obtain a detailed image. We present here the first analysis of the data provided by the IberArray broad-band seismic network that will allow a significant improvement the coverage of this area. The IberArray broad-band seismic network was deployed over this region for about 18 months, beginning in summer/fall 2007 in the framework of the large-scale Topo-Iberia project. This portable array, formed by up to 55 new generation dataloggers equipped with broad-band seismometers, has covered the southern part of Iberia (35 stations) and northern Morocco (20 stations) in an approximately regular grid, with a nominal spacing of 60 km. Data from more than 35 permanent broadband stations maintained by different institutions operating in the region has also been integrated into the IberArray database. Events with epicentral distances between 85 and 120 degrees and magnitude greater than 6.0 are systematically extracted from the continuous dataset and SKS and SKKS phases are inspected for anisotropy using the SplitLab software. Processing of the whole dataset is still ongoing, but the available results, including those for the entire year 2008, significantly improve the spatial resolution of SKS measurements in this region. The inferred fast velocity directions (FVD) clearly show a spectacular rotation along the Gibraltar arc, following the curvature of the Rif-Betic chain, from roughly N65E beneath the Betics to close to N65W beneath the Rif chain. Stations located in the South and South-east edges of the array, show a distinct pattern, with FVD oriented NE-SW to E-W. The results for some sites suggest the presence of complex anisotropy features, probably including two anisotropic layers. The obtained FVD results are compatible with rollback / subduction models, while convective-removal and delamination models seem unlikely to be compatible with our results. The FVD variations along the Gibraltar arc could be explained by fossil anisotropy acquired during the Eocene Western Mediterranean subduction, while the change in FVD observed to the South and South-East of the Rif-Betic chain can be related to the imprint of a flow episode around the Alboran high velocity slab during its Miocene fragmentation from the Algerian slab.

Vagal Intramuscular Arrays: The Specialized Mechanoreceptor Arbors That Innervate the Smooth Muscle Layers of the Stomach Examined in the Rat

PubMed Central

Powley, Terry L.; Hudson, Cherie N.; McAdams, Jennifer L.; Baronowsky, Elizabeth A.; Phillips, Robert J.

2016-01-01

The fundamental roles that the stomach plays in ingestion and digestion notwithstanding, little morphological information is available on vagal intramuscular arrays (IMAs), the afferents that innervate gastric smooth muscle. To characterize IMAs better, rats were given injections of dextran biotin in the nodose ganglia, and, after tracer transport, stomach whole mounts were collected. Specimens were processed for avidin–biotin permanent labeling, and subsets of the whole mounts were immunohistochemically processed for c-Kit or stained with cuprolinic blue. IMAs (n = 184) were digitized for morphometry and mapping. Throughout the gastric muscle wall, IMAs possessed common phenotypic features. Each IMA was generated by a parent neurite arborizing extensively, forming an array of multiple (mean = 212) branches averaging 193 μm in length. These branches paralleled, and coursed in apposition with, bundles of muscle fibers and interstitial cells of Cajal. Individual arrays averaged 4.3 mm in length and innervated volumes of muscle sheet, presumptive receptive fields, averaging 0.1 mm3. Evaluated by region and by muscle sheet, IMAs displayed architectural adaptations to the different loci. A subset (32%) of circular muscle IMAs issued specialized polymorphic collaterals to myenteric ganglia, and a subset (41%) of antral longitudinal muscle IMAs formed specialized net endings associated with the serosal boundary. IMAs were concentrated in regional patterns that correlated with the unique biomechanical adaptations of the stomach, specifically proximal stomach reservoir functions and antral emptying operations. Overall, the structural adaptations and distributions of the IMAs were consonant with the hypothesized stretch receptor roles of the afferents. PMID:26355387

Adaptive smart simulator for characterization and MPPT construction of PV array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouada, Mehdi, E-mail: mehdi.ouada@univ-annaba.org; Meridjet, Mohamed Salah; Dib, Djalel

2016-07-25

Partial shading conditions are among the most important problems in large photovoltaic array. Many works of literature are interested in modeling, control and optimization of photovoltaic conversion of solar energy under partial shading conditions, The aim of this study is to build a software simulator similar to hard simulator and to produce a shading pattern of the proposed photovoltaic array in order to use the delivered information to obtain an optimal configuration of the PV array and construct MPPT algorithm. Graphical user interfaces (Matlab GUI) are built using a developed script, this tool is easy to use, simple, and hasmore » a rapid of responsiveness, the simulator supports large array simulations that can be interfaced with MPPT and power electronic converters.« less

Flexible retinal electrode array

DOEpatents

Okandan, Murat [Albuquerque, NM; Wessendorf, Kurt O [Albuquerque, NM; Christenson, Todd R [Albuquerque, NM

2006-10-24

An electrode array which has applications for neural stimulation and sensing. The electrode array can include a large number of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. The electrode array can be formed from a combination of bulk and surface micromachining, with electrode tips that can include an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis where the electrodes can be tailored to provide a uniform gentle contact pressure with optional sensing of this contact pressure at one or more of the electrodes.

Dynamically Reconfigurable Systolic Array Accelerator

NASA Technical Reports Server (NTRS)

Dasu, Aravind; Barnes, Robert

2012-01-01

A polymorphic systolic array framework has been developed that works in conjunction with an embedded microprocessor on a field-programmable gate array (FPGA), which allows for dynamic and complimentary scaling of acceleration levels of two algorithms active concurrently on the FPGA. Use is made of systolic arrays and a hardware-software co-design to obtain an efficient multi-application acceleration system. The flexible and simple framework allows hosting of a broader range of algorithms, and is extendable to more complex applications in the area of aerospace embedded systems. FPGA chips can be responsive to realtime demands for changing applications needs, but only if the electronic fabric can respond fast enough. This systolic array framework allows for rapid partial and dynamic reconfiguration of the chip in response to the real-time needs of scalability, and adaptability of executables.

An Approach for Smart Antenna Testbed

NASA Astrophysics Data System (ADS)

Kawitkar, R. S.; Wakde, D. G.

2003-07-01

The use of wireless, mobile, personal communications services are expanding rapidly. Adaptive or "Smart" antenna arrays can increase channel capacity through spatial division. Adaptive antennas can also track mobile users, improving both signal range and quality. For these reasons, smart antenna systems have attracted widespread interest in the telecommunications industry for applications to third generation wireless systems.This paper aims to design and develop an advanced antennas testbed to serve as a common reference for testing adaptive antenna arrays and signal combining algorithms, as well as complete systems. A flexible suite of off line processing software should be written using matlab to perform system calibration, test bed initialization, data acquisition control, data storage/transfer, off line signal processing and analysis and graph plotting. The goal of this paper is to develop low complexity smart antenna structures for 3G systems. The emphasis will be laid on ease of implementation in a multichannel / multi-user environment. A smart antenna test bed will be developed, and various state-of-the-art DSP structures and algorithms will be investigated.Facing the soaring demand for mobile communications, the use of smart antenna arrays in mobile communications systems to exploit spatial diversity to further improve spectral efficiency has recently received considerable attention. Basically, a smart antenna array comprises a number of antenna elements combined via a beamforming network (amplitude and phase control network). Some of the benefits that can be achieved by using SAS (Smart Antenna System) include lower mobile terminal power consumption, range extension, ISI reduction, higher data rate support, and ease of integration into the existing base station system. In terms of economic benefits, adaptive antenna systems employed at base station, though increases the per base station cost, can increase coverage area of each cell site, thereby reducing the total system cost dramatically - often by more than 50% without compromising the system performance. The testbed can be employed to illustrate enhancement of system capacity and service quality in wireless communications.

2015 Volcanic Tsunami Earthquake near Torishima Island: Array analysis of ocean bottom pressure gauge records

NASA Astrophysics Data System (ADS)

Fukao, Y.; Sugioka, H.; Ito, A.; Shiobara, H.; Sandanbata, O.; Watada, S.; Satake, K.

2016-12-01

An array of ocean bottom pressure gauges was deployed off east of Aogashima island of the Izu-Bonin arc from May 2014 to May 2015. The array consists of 10 ocean bottom pressure gauges using ParoScientific quartz resonators which can measure absolute water pressure at 7000m depth with nano-resolution. The array configures equilateral triangles with minimum and maximum lengths of 10 and 30km. This array recorded seismic and tsunami waves from the CLVD-type earthquake (M5.7) of May 02, 2015, that occurred near Torishima Island 100 km distant from the array. Comparison with records of ordinary thrust earthquakes with similar magnitudes at similar distances indicates that this event generated anomalously large tsunamis relative to seismic waves. We made an array analysis for the phase speed, propagating azimuth and travel time of tsunami wave in a frequency range 1-10 mHz, where the dispersion effect is significant. The results show excellent agreements with the frequency-dependent ray-tracing calculations. The tsunami trace apparently starts with positive onset (pressure increase) and reaches a maximum amplitude of about 200Pa (≈2cm in tsunami height). A closer inspection, however, shows a preceding negative small pulse (Fig. 1), suggesting that the seafloor deformation at the tsunami source consists of a central large uplift and a peripheral small depression. This mode of deformation is qualitatively consistent with a finite CLVD source uniformly shortened laterally and uniformly stretched vertically without volume change. The detection of weak initial motions is indebted to the array deployment of sensitive pressure gauges far away from coastal regions. The bandpass-filtered waveform is drastically different between the lower and higher frequency ranges. The waveform is single-peaked in the lower frequency range (<5 mHz) but is ringing in the higher frequency range (>5 mHz), corresponding to the tsunami spectrum that consists of the broad primary peak around 3.5 mHz and the sharp double peaks at around 6.5 and 9 mHz. We interpret the broad primary peak as due to the tsunami source associated with seafloor deformation and the sharp double peaks as due to wave resonance (seiche) inside the Smith Caldera.

High Dynamic Range Spectral Imaging Pipeline For Multispectral Filter Array Cameras.

PubMed

Lapray, Pierre-Jean; Thomas, Jean-Baptiste; Gouton, Pierre

2017-06-03

Spectral filter arrays imaging exhibits a strong similarity with color filter arrays. This permits us to embed this technology in practical vision systems with little adaptation of the existing solutions. In this communication, we define an imaging pipeline that permits high dynamic range (HDR)-spectral imaging, which is extended from color filter arrays. We propose an implementation of this pipeline on a prototype sensor and evaluate the quality of our implementation results on real data with objective metrics and visual examples. We demonstrate that we reduce noise, and, in particular we solve the problem of noise generated by the lack of energy balance. Data are provided to the community in an image database for further research.

Chemotaxis cluster 1 proteins form cytoplasmic arrays in Vibrio cholerae and are stabilized by a double signaling domain receptor DosM.

PubMed

Briegel, Ariane; Ortega, Davi R; Mann, Petra; Kjær, Andreas; Ringgaard, Simon; Jensen, Grant J

2016-09-13

Nearly all motile bacterial cells use a highly sensitive and adaptable sensory system to detect changes in nutrient concentrations in the environment and guide their movements toward attractants and away from repellents. The best-studied bacterial chemoreceptor arrays are membrane-bound. Many motile bacteria contain one or more additional, sometimes purely cytoplasmic, chemoreceptor systems. Vibrio cholerae contains three chemotaxis clusters (I, II, and III). Here, using electron cryotomography, we explore V. cholerae's cytoplasmic chemoreceptor array and establish that it is formed by proteins from cluster I. We further identify a chemoreceptor with an unusual domain architecture, DosM, which is essential for formation of the cytoplasmic arrays. DosM contains two signaling domains and spans the two-layered cytoplasmic arrays. Finally, we present evidence suggesting that this type of receptor is important for the structural stability of the cytoplasmic array.

Interpopulational variation in the cold tolerance of a broadly distributed marine copepod

PubMed Central

Wallace, Gemma T.; Kim, Tiffany L.; Neufeld, Christopher J.

2014-01-01

Latitudinal trends in cold tolerance have been observed in many terrestrial ectotherms, but few studies have investigated interpopulational variation in the cold physiology of marine invertebrates. Here, the intertidal copepod Tigriopus californicus was used as a model system to study how local adaptation influences the cold tolerance of a broadly distributed marine crustacean. Among five populations spanning 18° in latitude, the following three metrics were used to compare cold tolerance: the temperature of chill-coma onset, the chill-coma recovery time and post-freezing recovery. In comparison to copepods from warmer southern latitudes, animals from northern populations exhibited lower chill-coma onset temperatures, shorter chill-coma recovery times and faster post-freezing recovery rates. Importantly, all three metrics showed a consistent latitudinal trend, suggesting that any single metric could be used equivalently in future studies investigating latitudinal variation in cold tolerance. Our results agree with previous studies showing that populations within a single species can display strong local adaptation to spatially varying climatic conditions. Thus, accounting for local adaptation in bioclimate models will be useful for understanding how broadly distributed species like T. californicus will respond to anthropogenic climate change. PMID:27293662

Interpopulational variation in the cold tolerance of a broadly distributed marine copepod.

PubMed

Wallace, Gemma T; Kim, Tiffany L; Neufeld, Christopher J

2014-01-01

Latitudinal trends in cold tolerance have been observed in many terrestrial ectotherms, but few studies have investigated interpopulational variation in the cold physiology of marine invertebrates. Here, the intertidal copepod Tigriopus californicus was used as a model system to study how local adaptation influences the cold tolerance of a broadly distributed marine crustacean. Among five populations spanning 18° in latitude, the following three metrics were used to compare cold tolerance: the temperature of chill-coma onset, the chill-coma recovery time and post-freezing recovery. In comparison to copepods from warmer southern latitudes, animals from northern populations exhibited lower chill-coma onset temperatures, shorter chill-coma recovery times and faster post-freezing recovery rates. Importantly, all three metrics showed a consistent latitudinal trend, suggesting that any single metric could be used equivalently in future studies investigating latitudinal variation in cold tolerance. Our results agree with previous studies showing that populations within a single species can display strong local adaptation to spatially varying climatic conditions. Thus, accounting for local adaptation in bioclimate models will be useful for understanding how broadly distributed species like T. californicus will respond to anthropogenic climate change.

In Vitro Neutralisation of Rotavirus Infection by Two Broadly Specific Recombinant Monovalent Llama-Derived Antibody Fragments

PubMed Central

Aladin, Farah; Einerhand, Alexandra W. C.; Bouma, Janneke; Bezemer, Sandra; Hermans, Pim; Wolvers, Danielle; Bellamy, Kate; Frenken, Leon G. J.; Gray, Jim; Iturriza-Gómara, Miren

2012-01-01

Rotavirus is the main cause of viral gastroenteritis in young children. Therefore, the development of inexpensive antiviral products for the prevention and/or treatment of rotavirus disease remains a priority. Previously we have shown that a recombinant monovalent antibody fragment (referred to as Anti-Rotavirus Proteins or ARP1) derived from a heavy chain antibody of a llama immunised with rotavirus was able to neutralise rotavirus infection in a mouse model system. In the present work we investigated the specificity and neutralising activity of two llama antibody fragments, ARP1 and ARP3, against 13 cell culture adapted rotavirus strains of diverse genotypes. In addition, immunocapture electron microscopy (IEM) was performed to determine binding of ARP1 to clinical isolates and cell culture adapted strains. ARP1 and ARP3 were able to neutralise a broad variety of rotavirus serotypes/genotypes in vitro, and in addition, IEM showed specific binding to a variety of cell adapted strains as well as strains from clinical specimens. These results indicated that these molecules could potentially be used as immunoprophylactic and/or immunotherapeutic products for the prevention and/or treatment of infection of a broad range of clinically relevant rotavirus strains. PMID:22403728

VizieR Online Data Catalog: MALT-45, a 7mm survey of the southern Galaxy (Jordan+, 2015)

NASA Astrophysics Data System (ADS)

Jordan, C. H.; Walsh, A. J.; Lowe, V.; Voronkov, M. A.; Ellingsen, S. P.; Breen, S. L.; Purcell, C. R.; Barnes, P. J.; Burton, M. G.; Cunningham, M. R.; Hill, T.; Jackson, J. M.; Longmore, S. N.; Peretto, N.; Urquhart, J. S.

2018-03-01

MALT-45 is an untargeted Galactic plane survey for spectral lines which are commonly bright in star-forming regions at 45GHz (7mm waveband). We have so far observed 5 square degrees within the region bounded by 330°<=l<=335°, b=+/-0.5°. MALT-45 observations were conducted on the Australia Telescope Compact Array (ATCA), which provides 2x2048MHz broad-band continuum windows for observing. Section 1.1 discusses the primary lines surveyed, and their rest frequencies dictate the positions of the broad-band windows for MALT-45. Within the frequency ranges of the broad-band windows, we survey for 12 spectral lines. (2 data files).

Oligonucleotide arrays vs. metaphase-comparative genomic hybridisation and BAC arrays for single-cell analysis: first applications to preimplantation genetic diagnosis for Robertsonian translocation carriers.

PubMed

Ramos, Laia; del Rey, Javier; Daina, Gemma; García-Aragonés, Manel; Armengol, Lluís; Fernandez-Encinas, Alba; Parriego, Mònica; Boada, Montserrat; Martinez-Passarell, Olga; Martorell, Maria Rosa; Casagran, Oriol; Benet, Jordi; Navarro, Joaquima

2014-01-01

Comprehensive chromosome analysis techniques such as metaphase-Comparative Genomic Hybridisation (CGH) and array-CGH are available for single-cell analysis. However, while metaphase-CGH and BAC array-CGH have been widely used for Preimplantation Genetic Diagnosis, oligonucleotide array-CGH has not been used in an extensive way. A comparison between oligonucleotide array-CGH and metaphase-CGH has been performed analysing 15 single fibroblasts from aneuploid cell-lines and 18 single blastomeres from human cleavage-stage embryos. Afterwards, oligonucleotide array-CGH and BAC array-CGH were also compared analysing 16 single blastomeres from human cleavage-stage embryos. All three comprehensive analysis techniques provided broadly similar cytogenetic profiles; however, non-identical profiles appeared when extensive aneuploidies were present in a cell. Both array techniques provided an optimised analysis procedure and a higher resolution than metaphase-CGH. Moreover, oligonucleotide array-CGH was able to define extra segmental imbalances in 14.7% of the blastomeres and it better determined the specific unbalanced chromosome regions due to a higher resolution of the technique (≈ 20 kb). Applicability of oligonucleotide array-CGH for Preimplantation Genetic Diagnosis has been demonstrated in two cases of Robertsonian translocation carriers 45,XY,der(13;14)(q10;q10). Transfer of euploid embryos was performed in both cases and pregnancy was achieved by one of the couples. This is the first time that an oligonucleotide array-CGH approach has been successfully applied to Preimplantation Genetic Diagnosis for balanced chromosome rearrangement carriers.

Oligonucleotide Arrays vs. Metaphase-Comparative Genomic Hybridisation and BAC Arrays for Single-Cell Analysis: First Applications to Preimplantation Genetic Diagnosis for Robertsonian Translocation Carriers

PubMed Central

Ramos, Laia; del Rey, Javier; Daina, Gemma; García-Aragonés, Manel; Armengol, Lluís; Fernandez-Encinas, Alba; Parriego, Mònica; Boada, Montserrat; Martinez-Passarell, Olga; Martorell, Maria Rosa; Casagran, Oriol; Benet, Jordi; Navarro, Joaquima

2014-01-01

Comprehensive chromosome analysis techniques such as metaphase-Comparative Genomic Hybridisation (CGH) and array-CGH are available for single-cell analysis. However, while metaphase-CGH and BAC array-CGH have been widely used for Preimplantation Genetic Diagnosis, oligonucleotide array-CGH has not been used in an extensive way. A comparison between oligonucleotide array-CGH and metaphase-CGH has been performed analysing 15 single fibroblasts from aneuploid cell-lines and 18 single blastomeres from human cleavage-stage embryos. Afterwards, oligonucleotide array-CGH and BAC array-CGH were also compared analysing 16 single blastomeres from human cleavage-stage embryos. All three comprehensive analysis techniques provided broadly similar cytogenetic profiles; however, non-identical profiles appeared when extensive aneuploidies were present in a cell. Both array techniques provided an optimised analysis procedure and a higher resolution than metaphase-CGH. Moreover, oligonucleotide array-CGH was able to define extra segmental imbalances in 14.7% of the blastomeres and it better determined the specific unbalanced chromosome regions due to a higher resolution of the technique (≈20 kb). Applicability of oligonucleotide array-CGH for Preimplantation Genetic Diagnosis has been demonstrated in two cases of Robertsonian translocation carriers 45,XY,der(13;14)(q10;q10). Transfer of euploid embryos was performed in both cases and pregnancy was achieved by one of the couples. This is the first time that an oligonucleotide array-CGH approach has been successfully applied to Preimplantation Genetic Diagnosis for balanced chromosome rearrangement carriers. PMID:25415307

Monolithically integrated broad-band Mach-Zehnder interferometers for highly sensitive label-free detection of biomolecules through dual polarization optics.

PubMed

Psarouli, A; Salapatas, A; Botsialas, A; Petrou, P S; Raptis, I; Makarona, E; Jobst, G; Tukkiniemi, K; Sopanen, M; Stoffer, R; Kakabakos, S E; Misiakos, K

2015-12-02

Protein detection and characterization based on Broad-band Mach-Zehnder Interferometry is analytically outlined and demonstrated through a monolithic silicon microphotonic transducer. Arrays of silicon light emitting diodes and monomodal silicon nitride waveguides forming Mach-Zehnder interferometers were integrated on a silicon chip. Broad-band light enters the interferometers and exits sinusoidally modulated with two distinct spectral frequencies characteristic of the two polarizations. Deconvolution in the Fourier transform domain makes possible the separation of the two polarizations and the simultaneous monitoring of the TE and the TM signals. The dual polarization analysis over a broad spectral band makes possible the refractive index calculation of the binding adlayers as well as the distinction of effective medium changes into cover medium or adlayer ones. At the same time, multi-analyte detection at concentrations in the pM range is demonstrated.

Health Matters: From Research to Practice. Research Brief. Winter 2014

ERIC Educational Resources Information Center

Kleinert, Harold L.; Sheppard-Jones, Kathy

2014-01-01

Kentucky has been focused upon improving outcomes for individuals receiving Supports for Community Living (SCL) Waiver services. SCL is the state's residential Medicaid developmental disabilities waiver; the SCL waiver provides a broad array of services for waiver recipients (residential, supported employment, transportation, community access,…

HOLISTIC APPROACH FOR ASSESSING THE PRESENCE AND POTENTIAL IMPACTS OF WATERBORNE ENVIRONMENTAL CONTAMINANTS

EPA Science Inventory

As an integral part of our continuing research in environmental quality assessment approaches, we have developed a variety of passive integrative sampling devices widely applicable for use in defining the presence and potential impacts of a broad array of contaminants. The semipe...

The Utility of the Small Rodent Electrocardiogram in Toxicology

EPA Science Inventory

Extensive research has lead to a growing appreciation that the heart is acutely sensitive to a broad array of toxicants via multiple routes of exposure. These agents are as diverse as the anti-neoplastic drug doxorubicin and various components of ambient air pollution. Adverse ef...

Exact least squares adaptive beamforming using an orthogonalization network

NASA Astrophysics Data System (ADS)

Yuen, Stanley M.

1991-03-01

The pros and cons of various classical and state-of-the-art methods in adaptive array processing are discussed, and the relevant concepts and historical developments are pointed out. A set of easy-to-understand equations for facilitating derivation of any least-squares-based algorithm is derived. Using this set of equations and incorporating all of the useful properties associated with various techniques, an efficient solution to the real-time adaptive beamforming problem is developed.

Directed evolution of adaptive traits

USDA-ARS?s Scientific Manuscript database

As a species, switchgrass is adapted to an amazingly broad range of environments, spanning hardiness zones ranging from HZ3 to HZ9 (Canada to Mexico), from the mid-grass prairie to the Atlantic Seaboard, from sandy soils to heavy clay soils, from acid to alkaline soils, and from wetland to dryland h...

Computer-Adaptive Testing in Second Language Contexts.

ERIC Educational Resources Information Center

Chalhoub-Deville, Micheline; Deville, Craig

1999-01-01

Provides a broad overview of computerized testing issues with an emphasis on computer-adaptive testing (CAT). A survey of the potential benefits and drawbacks of CAT are given, the process of CAT development is described; and some L2 instruments developed to assess various language skills are summarized. (Author/VWL)

Adaptive antenna arrays for satellite communications: Design and testing

NASA Technical Reports Server (NTRS)

Gupta, I. J.; Swarner, W. G.; Walton, E. K.

1985-01-01

When two separate antennas are used with each feedback loop to decorrelate noise, the antennas should be located such that the phase of the interfering signal in the two antennas is the same while the noise in them is uncorrelated. Thus, the antenna patterns and spatial distribution of the auxiliary antennas are quite important and should be carefully selected. The selection and spatial distribution of auxiliary elements is discussed when the main antenna is a center fed reflector antenna. It is shown that offset feeds of the reflector antenna can be used as auxiliary elements of an adaptive array to suppress weak interfering signals. An experimental system is designed to verify the theoretical analysis. The details of the experimental systems are presented.

A fast adaptive convex hull algorithm on two-dimensional processor arrays with a reconfigurable BUS system

NASA Technical Reports Server (NTRS)

Olariu, S.; Schwing, J.; Zhang, J.

1991-01-01

A bus system that can change dynamically to suit computational needs is referred to as reconfigurable. We present a fast adaptive convex hull algorithm on a two-dimensional processor array with a reconfigurable bus system (2-D PARBS, for short). Specifically, we show that computing the convex hull of a planar set of n points taken O(log n/log m) time on a 2-D PARBS of size mn x n with 3 less than or equal to m less than or equal to n. Our result implies that the convex hull of n points in the plane can be computed in O(1) time in a 2-D PARBS of size n(exp 1.5) x n.

Time-delayed directional beam phased array antenna

DOEpatents

Fund, Douglas Eugene; Cable, John William; Cecil, Tony Myron

2004-10-19

An antenna comprising a phased array of quadrifilar helix or other multifilar antenna elements and a time-delaying feed network adapted to feed the elements. The feed network can employ a plurality of coaxial cables that physically bridge a microstrip feed circuitry to feed power signals to the elements. The cables provide an incremental time delay which is related to their physical lengths, such that replacing cables having a first set of lengths with cables having a second set of lengths functions to change the time delay and shift or steer the antenna's main beam. Alternatively, the coaxial cables may be replaced with a programmable signal processor unit adapted to introduce the time delay using signal processing techniques applied to the power signals.

Performance of a modified feedback loop adaptive array with TVRO satellite signals

NASA Technical Reports Server (NTRS)

Steadman, Karl N.; Gupta, Inder J.; Walton, Eric K.

1990-01-01

Performance of an experimental adaptive antenna array system is evaluated using television receive-only (TVRO) satellite signals. The experimental system is a sidelobe canceller with two auxiliary channels. Modified feedback loops are used to enhance the suppression of weak interfering signals. The modified feedback loops used two spatialy separated antennas, each with an individual amplifier for each auxiliary channel. Thus, the experimental system uses five antenna elements. Instead of using five separate antennas, a reflector antenna with multiple feeds is used to receive signals from various TVRO satellites. The details of the earth station are given. It is shown that the experimental system can null up to two signals originating from interfering TVRO satellites while receiving the signals from a desired TVRO satellite.

Limited potential for adaptation to climate change in a broadly distributed marine crustacean.

PubMed

Kelly, Morgan W; Sanford, Eric; Grosberg, Richard K

2012-01-22

The extent to which acclimation and genetic adaptation might buffer natural populations against climate change is largely unknown. Most models predicting biological responses to environmental change assume that species' climatic envelopes are homogeneous both in space and time. Although recent discussions have questioned this assumption, few empirical studies have characterized intraspecific patterns of genetic variation in traits directly related to environmental tolerance limits. We test the extent of such variation in the broadly distributed tidepool copepod Tigriopus californicus using laboratory rearing and selection experiments to quantify thermal tolerance and scope for adaptation in eight populations spanning more than 17° of latitude. Tigriopus californicus exhibit striking local adaptation to temperature, with less than 1 per cent of the total quantitative variance for thermal tolerance partitioned within populations. Moreover, heat-tolerant phenotypes observed in low-latitude populations cannot be achieved in high-latitude populations, either through acclimation or 10 generations of strong selection. Finally, in four populations there was no increase in thermal tolerance between generations 5 and 10 of selection, suggesting that standing variation had already been depleted. Thus, plasticity and adaptation appear to have limited capacity to buffer these isolated populations against further increases in temperature. Our results suggest that models assuming a uniform climatic envelope may greatly underestimate extinction risk in species with strong local adaptation.

An Eye-adapted Beamforming for Axial B-scans Free from Crystalline Lens Aberration: In vitro and ex vivo Results with a 20 MHz Linear Array

NASA Astrophysics Data System (ADS)

Matéo, Tony; Mofid, Yassine; Grégoire, Jean-Marc; Ossant, Frédéric

In ophtalmic ultrasonography, axial B-scans are seriously deteriorated owing to the presence of the crystalline lens. This strongly aberrating medium affects both spatial and contrast resolution and causes important distortions. To deal with this issue, an adapted beamforming (BF) has been developed and experimented with a 20 MHz linear array working with a custom US research scanner. The adapted BF computes focusing delays that compensate for crystalline phase aberration, including refraction effects. This BF was tested in vitro by imaging a wire phantom through an eye phantom consisting of a synthetic gelatin lens, shaped according to the unaccommodated state of an adult human crystalline lens, anatomically set up in an appropriate liquid (turpentine) to approach the in vivo velocity ratio. Both image quality and fidelity from the adapted BF were assessed and compared with conventional delay-and-sum BF over the aberrating medium. Results showed 2-fold improvement of the lateral resolution, greater sensitivity and 90% reduction of the spatial error (from 758 μm to 76 μm) with adapted BF compared to conventional BF. Finally, promising first ex vivo axial B-scans of a human eye are presented.

Analysis of volcano-related seismicity to constrain the magmatic plumbing system beneath Fogo, Cape Verde, by (multi-)array techniques

NASA Astrophysics Data System (ADS)

Dietrich, Carola; Wölbern, Ingo; Faria, Bruno; Rümpker, Georg

2017-04-01

Fogo is the only island of the Cape Verde archipelago with regular occurring volcanic eruptions since its discovery in the 15th century. The volcanism of the archipelago originates from a mantle plume beneath an almost stationary tectonic plate. With an eruption interval of approximately 20 years, Fogo belongs to the most active oceanic volcanoes. The latest eruption started in November 2014 and ceased in February 2015. This study aims to characterize and investigate the seismic activity and the magmatic plumbing system of Fogo, which is believed to be related to a magmatic source close to the neighboring island of Brava. According to previous studies, using conventional seismic network configurations, most of the seismic activity occurs offshore. Therefore, seismological array techniques represent powerful tools in investigating earthquakes and other volcano-related events located outside of the networks. Another advantage in the use of seismic arrays is their possibility to detect events of relatively small magnitude and to locate seismic signals without a clear onset of phases, such as volcanic tremors. Since October 2015 we have been operating a test array on Fogo as part of a pilot study. This array consists of 10 seismic stations, distributed in a circular shape with an aperture of 700 m. The stations are equipped with Omnirecs CUBE dataloggers, and either 4.5 Hz geophones (7 stations) or Trillium-Compact broad-band seismometers (3 stations). In January 2016 we installed three additional broad-band stations distributed across the island of Fogo to improve the capabilities for event localization. The data of the pilot study is dominated by seismic activity around Brava, but also exhibit tremors and hybrid events of unknown origin within the caldera of Fogo volcano. The preliminary analysis of these events includes the characterization and localization of the different event types using seismic array processing in combination with conventional localization methods. In the beginning of August 2016, a "seismic crisis" occurred on the island of Brava which led to the evacuation of a village. The seismic activity recorded by our instruments on Fogo exhibits more than 40 earthquakes during this time. Locations and magnitudes of these events will be presented. In January 2017 the pilot project discussed here will be complemented by three additional seismic arrays (two on Fogo, one on Brava) to improve seismic event localization and structural imaging based on scattered seismic phases by using multi-array techniques. Initial recordings from the new arrays are expected to be available by April 2017.

Transmission mode adaptive beamforming for planar phased arrays and its application to 3D ultrasonic transcranial imaging

NASA Astrophysics Data System (ADS)

Shapoori, Kiyanoosh; Sadler, Jeffrey; Wydra, Adrian; Malyarenko, Eugene; Sinclair, Anthony; Maev, Roman G.

2013-03-01

A new adaptive beamforming method for accurately focusing ultrasound behind highly scattering layers of human skull and its application to 3D transcranial imaging via small-aperture planar phased arrays are reported. Due to its undulating, inhomogeneous, porous, and highly attenuative structure, human skull bone severely distorts ultrasonic beams produced by conventional focusing methods in both imaging and therapeutic applications. Strong acoustical mismatch between the skull and brain tissues, in addition to the skull's undulating topology across the active area of a planar ultrasonic probe, could cause multiple reflections and unpredictable refraction during beamforming and imaging processes. Such effects could significantly deflect the probe's beam from the intended focal point. Presented here is a theoretical basis and simulation results of an adaptive beamforming method that compensates for the latter effects in transmission mode, accompanied by experimental verification. The probe is a custom-designed 2 MHz, 256-element matrix array with 0.45 mm element size and 0.1mm kerf. Through its small footprint, it is possible to accurately measure the profile of the skull segment in contact with the probe and feed the results into our ray tracing program. The latter calculates the new time delay patterns adapted to the geometrical and acoustical properties of the skull phantom segment in contact with the probe. The time delay patterns correct for the refraction at the skull-brain boundary and bring the distorted beam back to its intended focus. The algorithms were implemented on the ultrasound open-platform ULA-OP (developed at the University of Florence).

Prospects for Future Synergies Between SKA and AtLAST

NASA Astrophysics Data System (ADS)

Wagg, Jeff

2018-01-01

The Square Kilometre Array will be the next major global radio astronomy observatory. Being built in two phases, the first phase will consist of a low frequency array in Australia and a mid to high frequency array of dishes in the Karoo of South Africa. The design of SKA1 is nearly complete with the expectation that construction should begin within the next two years. A significant fraction of the observing time on both SKA1-MID and SKA1-LOW will likely be devoted to large survey programmes covering a broad range of science objectives. Given the timeline for these SKA1 programmes to be completed, it is anticipated that they could naturally complement future high frequency surveys using AtLAST. I will highlight a few areas where such synergies should exist.

Metallic stereostructured layer: An approach for broadband polarization state manipulation

NASA Astrophysics Data System (ADS)

Xiong, Xiang; Hu, Yuan-Sheng; Jiang, Shang-Chi; Hu, Yu-Hui; Fan, Ren-Hao; Ma, Guo-Bin; Shu, Da-Jun; Peng, Ru-Wen; Wang, Mu

2014-11-01

In this letter, we report a full-metallic broadband wave plate assembled by standing metallic L-shaped stereostructures (LSSs). We show that with an array of LSSs, high polarization conversion ratio is achieved within a broad frequency band. Moreover, by rotating the orientation of the array of LSSs, the electric components of the reflection beam in two orthogonal directions and their phase difference can be independently tuned. In this way, all the polarization states on the Poincaré sphere can be realized. As examples, the functionalities of a quarter wave plate and a half wave plate are experimentally demonstrated with both reflection spectra and focal-plane-array imaging. Our designing provides a unique approach in realizing the broadband wave plate to manipulate the polarization state of light.

Transport and collision dynamics in periodic asymmetric obstacle arrays: Rational design of microfluidic rare-cell immunocapture devices

NASA Astrophysics Data System (ADS)

Gleghorn, Jason P.; Smith, James P.; Kirby, Brian J.

2013-09-01

Microfluidic obstacle arrays have been used in numerous applications, and their ability to sort particles or capture rare cells from complex samples has broad and impactful applications in biology and medicine. We have investigated the transport and collision dynamics of particles in periodic obstacle arrays to guide the design of convective, rather than diffusive, transport-based immunocapture microdevices. Ballistic and full computational fluid dynamics simulations are used to understand the collision modes that evolve in cylindrical obstacle arrays with various geometries. We identify previously unrecognized collision mode structures and differential size-based collision frequencies that emerge from these arrays. Previous descriptions of transverse displacements that assume unidirectional flow in these obstacle arrays cannot capture mode transitions properly as these descriptions fail to capture the dependence of the mode transitions on column spacing and the attendant change in the flow field. Using these analytical and computational simulations, we elucidate design parameters that induce high collision rates for all particles larger than a threshold size or selectively increase collision frequencies for a narrow range of particle sizes within a polydisperse population. Furthermore, we investigate how the particle Péclet number affects collision dynamics and mode transitions and demonstrate that experimental observations from various obstacle array geometries are well described by our computational model.

Photon Transport in One-Dimensional Incommensurately Epitaxial CsPbX 3 Arrays

DOE PAGES

Wang, Yiping; Sun, Xin; Shivanna, Ravichandran; ...

2016-11-16

One-dimensional nanoscale epitaxial arrays serve as a great model in studying fundamental physics and for emerging applications. With an increasing focus laid on the Cs-based inorganic halide perovskite out of its outstanding material stability, we have applied vapor phase epitaxy to grow well aligned horizontal CsPbX 3 (X: Cl, Br, or I or their mixed) nanowire arrays in large scale on mica substrate. The as-grown nanowire features a triangular prism morphology with typical length ranging from a few tens of micrometers to a few millimeters. Structural analysis reveals that the wire arrays follow the symmetry of mica substrate through incommensuratemore » epitaxy, paving a way for a universally applicable method to grow a broad family of halide perovskite materials. We have studied the unique photon transport in the one-dimensional structure in the all-inorganic Cs-based perovskite wires via temperature dependent and spatially resolved photoluminescence. Furthermore, epitaxy of well oriented wire arrays in halide perovskite would be a promising direction for enabling the circuit-level applications of halide perovskite in high-performance electro-optics and optoelectronics.« less

Comprehension of the Representational Mind in Infancy

ERIC Educational Resources Information Center

Caron, Albert J.

2009-01-01

A broad array of infant studies are reviewed that appear to be consistent with the idea that belief understanding specifically, and mental attribution generally, emerge much earlier than previously acknowledged. We first examine existing false-belief research, which, while confirming that children under 4 years perform poorly on standard tests,…

The California School Psychologist, 2001.

ERIC Educational Resources Information Center

Jimerson, Shane R., Ed.; Wilson, Marilyn, Ed.

2001-01-01

This volume of the journal for the California Association of School Psychologists provides current information on a broad array of topics related to the work of school psychologists. The articles contribute important information on contemporary issues in the field, such as using a strength-based perspective when assessing students, student support…

Continuing Medical Education, Perspectives, Problems, Prognosis.

ERIC Educational Resources Information Center

Richards, Robert K.

Predicting that continuing medical education (CME) will be mandatory for doctors within five years, this book traces CME's historical antecedents, analyzes the forces arrayed for and against it, and offers guidelines for its realistic use in a broad program of improving health care. An examination is made of: the evolution of undergraduate and…

Demystifying Organizational Transformation: A Poetical Look at "Tomorrow's Schools".

ERIC Educational Resources Information Center

Mitchell, Brad; Varner, Donna

It is widely assumed that empowerment represents the organizational transformation strategy to help schools fulfill a broad array of announced goals, such as academic excellence, economic prosperity, military security, and social equity. This paper directs a demystifying light on the rhetoric and rationality of organizational transformation theory…

Why Save Wilderness?--Fruits and Veggies!

ERIC Educational Resources Information Center

Kowalewski, David

2015-01-01

Why save wilderness? Environmental educators usually offer ecosystemic and aesthetic reasons, yet clearly this abstract approach has failed to resonate with the wider public. In this article I adopt a nutritional strategy based on a broad array of sources. Wild plant food, in terms of economics, ubiquity, and other measures, performs very well…

Discovering History at the Community College

ERIC Educational Resources Information Center

Tai, Emily Sohmer

2013-01-01

Many of the history courses community college students take are fairly broad and ostensibly generic surveys of world, Western European, or American history. This chapter discusses an array of innovative practices that enable students to better appreciate how studying history can help them master the challenges--and reap the benefits--of a liberal…

The California School Psychologist, 2002.

ERIC Educational Resources Information Center

Jimerson, Shane R., Ed.

2002-01-01

This volume of the journal for the California Association of School Psychologists provides current information on a broad array of topics related to the work of school psychologists. Articles in this volume provide information addressing an assortment of important issues in the field, including: the translations and validation of an assessment for…

A Review of Group Systems Theory

ERIC Educational Resources Information Center

Connors, Joanie V.; Caple, Richard B.

2005-01-01

The ability to see interpersonal and group processes beyond the individual level is an essential skill for group therapists (Crouch, Bloch & Wanlass, 1994; Dies, 1994; Fuhriman & Burlingame, 1994). In addition to interpersonal therapy models (e.g., Sullivan and Yalom), there are a number of systems theory models that offer a broad array of…

Individualized Education Programs for Youth with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Wilczynski, Susan M.; Menousek, Kathryn; Hunter, Melissa; Mudgal, Dipti

2007-01-01

Children with Autism Spectrum Disorders (ASD) present with a broad array of deficits and excesses that require educational intervention. The Individualized Education Program (IEP) serves as the blueprint for educational intervention but it can sometimes be difficult to identify which goals and objectives should be addressed with this population.…

Characteristics of the Research Supervision of Postgraduate Teachers' Action Research

ERIC Educational Resources Information Center

Cornelissen, Frank; van den Berg, Ellen

2014-01-01

Today, many institutions of higher education support students in conducting practice-oriented research. This research refers to a broad array of approaches geared toward practitioners' practice. The supervision of such research is of crucial importance, but little is known about its nature and characteristics. This study examined what research…

Teaching Strategies for Diverse Learners in FCS Classrooms

ERIC Educational Resources Information Center

Allison, Barbara N.; Rehm, Marsha L.

2007-01-01

The growing diversity in today's classrooms demands that family and consumer sciences (FCS) teachers be knowledgeable, responsive, and well-prepared to work with a multicultural, multilingual student population. To meet the needs of students from all backgrounds, FCS teachers must use a broad array of research-based strategies that support diverse…

THE FUTURE OF COMPUTER-BASED TOXICITY PREDICTION: MECHANISM-BASED MODELS VS. INFORMATION MINING APPROACHES

EPA Science Inventory

The Future of Computer-Based Toxicity Prediction:
Mechanism-Based Models vs. Information Mining Approaches

When we speak of computer-based toxicity prediction, we are generally referring to a broad array of approaches which rely primarily upon chemical structure ...

Moisture, plant-plant interactions and herbivory as drivers of rangeland restoration success in the western US

USDA-ARS?s Scientific Manuscript database

Restoration efforts in the western US occur across a diverse array of plant communities and climatic conditions. Restoration is likely constrained by different factors in different locations, but few efforts have compared the outcomes of rangeland restoration experiments across broad spatial scales....

Realizing structural color generation with aluminum plasmonic V-groove metasurfaces

DOE PAGES

Wang, Wei; Rosenmann, Daniel; Czaplewski, David A.; ...

2017-08-14

The structural color printing based on all-aluminum plasmonic V-groove metasurfaces is demonstrated under both bright field and dark field illumination conditions. A broad visible color range is realized with the plasmonic V-groove arrays etched on aluminum surface by simply varying the groove depth while keeping the groove period as a constant. Polarization dependent structural color printing is further achieved with interlaced V-groove arrays along both the horizontal and vertical directions. Furthermore, these results pave the way towards the use of all-aluminum structural color printing platform for many practical applications such as security marking and information storage.

Radiation Hardened Electronics for Extreme Environments

NASA Technical Reports Server (NTRS)

Keys, Andrew S.; Watson, Michael D.

2007-01-01

The Radiation Hardened Electronics for Space Environments (RHESE) project consists of a series of tasks designed to develop and mature a broad spectrum of radiation hardened and low temperature electronics technologies. Three approaches are being taken to address radiation hardening: improved material hardness, design techniques to improve radiation tolerance, and software methods to improve radiation tolerance. Within these approaches various technology products are being addressed including Field Programmable Gate Arrays (FPGA), Field Programmable Analog Arrays (FPAA), MEMS Serial Processors, Reconfigurable Processors, and Parallel Processors. In addition to radiation hardening, low temperature extremes are addressed with a focus on material and design approaches.

Realizing structural color generation with aluminum plasmonic V-groove metasurfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei; Rosenmann, Daniel; Czaplewski, David A.

The structural color printing based on all-aluminum plasmonic V-groove metasurfaces is demonstrated under both bright field and dark field illumination conditions. A broad visible color range is realized with the plasmonic V-groove arrays etched on aluminum surface by simply varying the groove depth while keeping the groove period as a constant. Polarization dependent structural color printing is further achieved with interlaced V-groove arrays along both the horizontal and vertical directions. Furthermore, these results pave the way towards the use of all-aluminum structural color printing platform for many practical applications such as security marking and information storage.

Map reading tools for map libraries.

USGS Publications Warehouse

Greenberg, G.L.

1982-01-01

Engineers, navigators and military strategists employ a broad array of mechanical devices to facilitate map use. A larger number of map users such as educators, students, tourists, journalists, historians, politicians, economists and librarians are unaware of the available variety of tools which can be used with maps to increase the speed and efficiency of their application and interpretation. This paper identifies map reading tools such as coordinate readers, protractors, dividers, planimeters, and symbol-templets according to a functional classification. Particularly, arrays of tools are suggested for use in determining position, direction, distance, area and form (perimeter-shape-pattern-relief). -from Author

Light polarization management via reflection from arrays of sub-wavelength metallic twisted bands

NASA Astrophysics Data System (ADS)

Nawrot, M.; Haberko, J.; Zinkiewicz, Ł.; Wasylczyk, P.

2017-12-01

With constant progress of nano- and microfabrication technologies, photolithography in particular, a number of sub-wavelength metallic structures have been demonstrated that can be used to manipulate light polarization. Numerical simulations of light propagation hint that helical twisted bands can have interesting polarization properties. We use three-dimensional two-photon photolithography (direct laser writing) to fabricate a few-micrometer-thick arrays of twisted bands and coat them uniformly with metal. We demonstrate that circular polarization can be generated from linear polarization upon reflection from such structures over a broad range of frequencies in the mid infrared.

OHANA, the Optical Hawaiian Array for Nanoradian Astronomy. Towards kilometric infrared arrays

NASA Astrophysics Data System (ADS)

Perrin, G.

Optical/Infrared Interferometry has become a mature technique with more and more astrophysical results in the past years. For historical and technical reasons, the traditional field of investigation of interferometers is stellar physics. With the advent of large telescopes and adaptive optics, more resolving and more sensitive interferometers are within reach with the promise to widen the target list. In particular, extragalactic sources will benefit from this revolution. A prototype instrument, 'OHANA, is described here. 'OHANA uses single-mode fibers to turn the large telescopes of the Mauna Kea summit into a large near-infrared kilometric array.

Integrated sensor with frame memory and programmable resolution for light adaptive imaging

NASA Technical Reports Server (NTRS)

Zhou, Zhimin (Inventor); Fossum, Eric R. (Inventor); Pain, Bedabrata (Inventor)

2004-01-01

An image sensor operable to vary the output spatial resolution according to a received light level while maintaining a desired signal-to-noise ratio. Signals from neighboring pixels in a pixel patch with an adjustable size are added to increase both the image brightness and signal-to-noise ratio. One embodiment comprises a sensor array for receiving input signals, a frame memory array for temporarily storing a full frame, and an array of self-calibration column integrators for uniform column-parallel signal summation. The column integrators are capable of substantially canceling fixed pattern noise.

Rapid recognition of volatile organic compounds with colorimetric sensor arrays for lung cancer screening.

PubMed

Zhong, Xianhua; Li, Dan; Du, Wei; Yan, Mengqiu; Wang, You; Huo, Danqun; Hou, Changjun

2018-06-01

Volatile organic compounds (VOCs) in breath can be used as biomarkers to identify early stages of lung cancer. Herein, we report a disposable colorimetric array that has been constructed from diverse chemo-responsive colorants. Distinguishable difference maps were plotted within 4 min for specifically targeted VOCs. Through the consideration of various chemical interactions with VOCs, the arrays successfully discriminate between 20 different volatile organic compounds in breath that are related to lung cancer. VOCs were identified either with the visualized difference maps or through pattern recognition with an accuracy of at least 90%. No uncertainties or errors were observed in the hierarchical cluster analysis (HCA). Finally, good reproducibility and stability of the array was achieved against changes in humidity. Generally, this work provides fundamental support for construction of simple and rapid VOC sensors. More importantly, this approach provides a hypothesis-free array method for breath testing via VOC profiling. Therefore, this small, rapid, non-invasive, inexpensive, and visualized sensor array is a powerful and promising tool for early screening of lung cancer. Graphical abstract A disposable colorimetric array has been developed with broadly chemo-responsive dyes to incorporate various chemical interactions, through which the arrays successfully discriminate 20 VOCs that are related to lung cancer via difference maps alone or chemometrics within 4 min. The hydrophobic porous matrix provides good stability against changes in humidity.

Intestinal mucosal atrophy and adaptation

PubMed Central

Shaw, Darcy; Gohil, Kartik; Basson, Marc D

2012-01-01

Mucosal adaptation is an essential process in gut homeostasis. The intestinal mucosa adapts to a range of pathological conditions including starvation, short-gut syndrome, obesity, and bariatric surgery. Broadly, these adaptive functions can be grouped into proliferation and differentiation. These are influenced by diverse interactions with hormonal, immune, dietary, nervous, and mechanical stimuli. It seems likely that clinical outcomes can be improved by manipulating the physiology of adaptation. This review will summarize current understanding of the basic science surrounding adaptation, delineate the wide range of potential targets for therapeutic intervention, and discuss how these might be incorporated into an overall treatment plan. Deeper insight into the physiologic basis of adaptation will identify further targets for intervention to improve clinical outcomes. PMID:23197881

Adaptive Control of Truss Structures for Gossamer Spacecraft

NASA Technical Reports Server (NTRS)

Yang, Bong-Jun; Calise, Anthony J.; Craig, James I.; Whorton, Mark S.

2007-01-01

Neural network-based adaptive control is considered for active control of a highly flexible truss structure which may be used to support solar sail membranes. The objective is to suppress unwanted vibrations in SAFE (Solar Array Flight Experiment) boom, a test-bed located at NASA. Compared to previous tests that restrained truss structures in planar motion, full three dimensional motions are tested. Experimental results illustrate the potential of adaptive control in compensating for nonlinear actuation and modeling error, and in rejecting external disturbances.

Light emitting diode excitation emission matrix fluorescence spectroscopy.

PubMed

Hart, Sean J; JiJi, Renée D

2002-12-01

An excitation emission matrix (EEM) fluorescence instrument has been developed using a linear array of light emitting diodes (LED). The wavelengths covered extend from the upper UV through the visible spectrum: 370-640 nm. Using an LED array to excite fluorescence emission at multiple excitation wavelengths is a low-cost alternative to an expensive high power lamp and imaging spectrograph. The LED-EEM system is a departure from other EEM spectroscopy systems in that LEDs often have broad excitation ranges which may overlap with neighboring channels. The LED array can be considered a hybrid between a spectroscopic and sensor system, as the broad LED excitation range produces a partially selective optical measurement. The instrument has been tested and characterized using fluorescent dyes: limits of detection (LOD) for 9,10-bis(phenylethynyl)-anthracene and rhodamine B were in the mid parts-per-trillion range; detection limits for the other compounds were in the low parts-per-billion range (< 5 ppb). The LED-EEMs were analyzed using parallel factor analysis (PARAFAC), which allowed the mathematical resolution of the individual contributions of the mono- and dianion fluorescein tautomers a priori. Correct identification and quantitation of six fluorescent dyes in two to six component mixtures (concentrations between 12.5 and 500 ppb) has been achieved with root mean squared errors of prediction (RMSEP) of less than 4.0 ppb for all components.

Successes and challenges from formation to implementation of eleven broad-extent conservation programs.

PubMed

Beever, Erik A; Mattsson, Brady J; Germino, Matthew J; Burg, Max Post Van Der; Bradford, John B; Brunson, Mark W

2014-04-01

Integration of conservation partnerships across geographic, biological, and administrative boundaries is increasingly relevant because drivers of change, such as climate shifts, transcend these boundaries. We explored successes and challenges of established conservation programs that span multiple watersheds and consider both social and ecological concerns. We asked representatives from a diverse set of 11 broad-extent conservation partnerships in 29 countries 17 questions that pertained to launching and maintaining partnerships for broad-extent conservation, specifying ultimate management objectives, and implementation and learning. Partnerships invested more funds in implementing conservation actions than any other aspect of conservation, and a program's context (geographic extent, United States vs. other countries, developed vs. developing nation) appeared to substantially affect program approach. Despite early successes of these organizations and benefits of broad-extent conservation, specific challenges related to uncertainties in scaling up information and to coordination in the face of diverse partner governance structures, conflicting objectives, and vast uncertainties regarding future system dynamics hindered long-term success, as demonstrated by the focal organizations. Engaging stakeholders, developing conservation measures, and implementing adaptive management were dominant challenges. To inform future research on broad-extent conservation, we considered several challenges when we developed detailed questions, such as what qualities of broad-extent partnerships ensure they complement, integrate, and strengthen, rather than replace, local conservation efforts and which adaptive management processes yield actionable conservation strategies that account explicitly for dynamics and uncertainties regarding multiscale governance, environmental conditions, and knowledge of the system? © 2014 Society for Conservation Biology.

Receiver Function Imaging of Crust and Uppermost Mantle Structure beneath the Japan Islands -Inclusion of Hi-net Data-

NASA Astrophysics Data System (ADS)

Yamauchi, M.; Hirahara, K.; Shibutani, T.

2001-12-01

We are examining a large number of teleseismic waveforms observed at stations closely distributed over the Japan Islands to construct body-wave waveform tomography data for determining 3-D crust and upper mantle structure including velocity discontinuities. As one of preparatory studies toward this final goal, we are executing array analyses of Receiver Functions (RF). RF analyses of J-array data ( 32 broad band stations and 269 short period stations ) and Freesia data ( 15 broad band stations ), whose stations are closely distributed, have provided us with new information on the structure including velocity discontinuities beneath the Japan Islands (Tada et al, 2001). In their study, for crustal imaging, RFs transformed from time to depth domain after SVD filtering ( Chevrot and Giardin, 2000 ) are projected onto 2-D profiles, which show average values for cells within +/- 50km from each cross section. However, this cell size does not satisfy our demand to draw the detailed image beneath the Japan Islands. In addition, J-array short period RFs available for the analyses are limited because of high frequency noises. In this research, Hi-net data (short period), whose stations are far more closely distributed, are newly included into our data. We make RF image with α =3 of short period J-array data and Hi-net data for events observed during a period from September, 2000 to July, 2001 with the magnitudes larger than 5.5. The total number of the stations with their average spacing of 10km is about 800 (J-array; 270, Hi-net; 500), which enables to reduce the cell size to +/- 20km at most. We show a new 3-D RF image of the crust and the uppermost mantle, whose best spatial resolution is reaching less than 5km. Therefore we can obtain much more detailed 3-D RF image beneath the whole Japan Islands.

Multivariate Dynamical Modeling to Investigate Human Adaptation to Space Flight: Initial Concepts

NASA Technical Reports Server (NTRS)

Shelhamer, Mark; Mindock, Jennifer; Zeffiro, Tom; Krakauer, David; Paloski, William H.; Lumpkins, Sarah

2014-01-01

The array of physiological changes that occur when humans venture into space for long periods presents a challenge to future exploration. The changes are conventionally investigated independently, but a complete understanding of adaptation requires a conceptual basis founded in intergrative physiology, aided by appropriate mathematical modeling. NASA is in the early stages of developing such an approach.

Multivariate Dynamic Modeling to Investigate Human Adaptation to Space Flight: Initial Concepts

NASA Technical Reports Server (NTRS)

Shelhamer, Mark; Mindock, Jennifer; Zeffiro, Tom; Krakauer, David; Paloski, William H.; Lumpkins, Sarah

2014-01-01

The array of physiological changes that occur when humans venture into space for long periods presents a challenge to future exploration. The changes are conventionally investigated independently, but a complete understanding of adaptation requires a conceptual basis founded in integrative physiology, aided by appropriate mathematical modeling. NASA is in the early stages of developing such an approach.

Diversity and habitat relationships of hypogeous fungi. III. Factors influencing the occurrence of fire-adapted species

Treesearch

Andrew W. Claridge; James M. Trappe; Douglas J. Mills; Debbie L. Claridge

2009-01-01

Among the huge array of hypogeous ectomycorrhizal fungi so far documented from Australia, six genera and more than 30 species occur within the family Mesophelliaceae, all of which show various adaptations for surviving in fire-prone landscapes. These mostly endemic fungi are critical to postfire reestablishment of regenerating vegetation, and their fruit-bodies provide...

Hybrid Active/Passive Jet Engine Noise Suppression System

NASA Technical Reports Server (NTRS)

Parente, C. A.; Arcas, N.; Walker, B. E.; Hersh, A. S.; Rice, E. J.

1999-01-01

A novel adaptive segmented liner concept has been developed that employs active control elements to modify the in-duct sound field to enhance the tone-suppressing performance of passive liner elements. This could potentially allow engine designs that inherently produce more tone noise but less broadband noise, or could allow passive liner designs to more optimally address high frequency broadband noise. A proof-of-concept validation program was undertaken, consisting of the development of an adaptive segmented liner that would maximize attenuation of two radial modes in a circular or annular duct. The liner consisted of a leading active segment with dual annuli of axially spaced active Helmholtz resonators, followed by an optimized passive liner and then an array of sensing microphones. Three successively complex versions of the adaptive liner were constructed and their performances tested relative to the performance of optimized uniform passive and segmented passive liners. The salient results of the tests were: The adaptive segmented liner performed well in a high flow speed model fan inlet environment, was successfully scaled to a high sound frequency and successfully attenuated three radial modes using sensor and active resonator arrays that were designed for a two mode, lower frequency environment.

Adaptive near-field beamforming techniques for sound source imaging.

PubMed

Cho, Yong Thung; Roan, Michael J

2009-02-01

Phased array signal processing techniques such as beamforming have a long history in applications such as sonar for detection and localization of far-field sound sources. Two sometimes competing challenges arise in any type of spatial processing; these are to minimize contributions from directions other than the look direction and minimize the width of the main lobe. To tackle this problem a large body of work has been devoted to the development of adaptive procedures that attempt to minimize side lobe contributions to the spatial processor output. In this paper, two adaptive beamforming procedures-minimum variance distorsionless response and weight optimization to minimize maximum side lobes--are modified for use in source visualization applications to estimate beamforming pressure and intensity using near-field pressure measurements. These adaptive techniques are compared to a fixed near-field focusing technique (both techniques use near-field beamforming weightings focusing at source locations estimated based on spherical wave array manifold vectors with spatial windows). Sound source resolution accuracies of near-field imaging procedures with different weighting strategies are compared using numerical simulations both in anechoic and reverberant environments with random measurement noise. Also, experimental results are given for near-field sound pressure measurements of an enclosed loudspeaker.

Linking Satellites Via Earth "Hot Spots" and the Internet to Form Ad Hoc Constellations

NASA Technical Reports Server (NTRS)

Mandl, Dan; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix; Lee, Richard Q.; Romanofsky, Robert; Zaman, Afoz; Popovic, Zoya

2004-01-01

As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet. the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in

 Climate change may trigger broad shifts in North America's Pacific Coastal rainforests

Treesearch

Dominick A. DellaSala; Patric Brandt; Marni   Koopman; Jessica Leonard; Claude Meisch; Patrick Herzog; Paul Alaback; Michael I. Goldstein; Sarah Jovan; Andy MacKinnon; Henrik von Wehrden

2015-01-01

Climate change poses significant threats to Pacific coastal rainforests of North America. Land managers currently lack a coordinated climate change adaptation approach with which to prepare the region's globally outstanding biodiversity for accelerating change. We provided analyses intended to inform coordinated adaptation for eight focal rainforest tree species...

Spatiotemporal variation in resource selection: Insights from the American marten (Martes Americana)

Treesearch

Andrew J. Shirk; Martin G. Raphael; Samuel A. Cushman

2014-01-01

Behavioral and genetic adaptations to spatiotemporal variation in habitat conditions allow species to maximize their biogeographic range and persist over time in dynamic environments. An understanding of these local adaptations can be used to guide management and conservation of populations over broad extents encompassing diverse habitats. This understanding is often...

Adaptation resources for agriculture: responding to climate variability and change in the midwest and northeast

USDA-ARS?s Scientific Manuscript database

This report is intended to provide perspective, information, and tools to support agricultural producers in the Midwest and Northeast regions of the U.S. in responding to climate variability and change. Climate change adaptation can be broadly defined to include all adjustments, both planned and unp...

Coherent acoustic communication in a tidal estuary with busy shipping traffic.

PubMed

van Walree, Paul A; Neasham, Jeffrey A; Schrijver, Marco C

2007-12-01

High-rate acoustic communication experiments were conducted in a dynamic estuarine environment. Two current profilers deployed in a shipping lane were interfaced with acoustic modems, which modulated and transmitted the sensor readings every 200 s over a period of four days. QPSK modulation was employed at a raw data rate of 8 kbits on a 12-kHz carrier. Two 16-element hydrophone arrays, one horizontal and one vertical, were deployed near the shore. A multichannel decision-feedback equalizer was used to demodulate the modem signals received on both arrays. Long-term statistical analysis reveals the effects of the tidal cycle, subsea unit location, attenuation by the wake of passing vessels, and high levels of ship-generated noise on the fidelity of the communication links. The use of receiver arrays enables vast improvement in the overall reliability of data delivery compared with a single-receiver system, with performance depending strongly on array orientation. The vertical array offers the best performance overall, although the horizontal array proves more robust against shipping noise. Spatial coherence estimates, variation of array aperture, and inspection of array angular responses point to adaptive beamforming and coherent combining as the chief mechanisms of array gain.

Optimized micromirror arrays for adaptive optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michalicek, M. Adrian

This paper describes the design, layout, fabrication, and surface characterization of highly optimized surface micromachined micromirror devices. Design considerations and fabrication capabilities are presented. These devices are fabricated in the state-of-the-art, four-level, planarized, ultra-low-stress polysilicon process available at Sandia National Laboratories known as the Sandia Ultra-planar Multi-level MEMS Technology (SUMMiT). This enabling process permits the development of micromirror devices with near-ideal characteristics that have previously been unrealizable in standard three-layer polysilicon processes. The reduced 1 {mu}m minimum feature sizes and 0.1 {mu}m mask resolution make it possible to produce dense wiring patterns and irregularly shaped flexures. Likewise, mirror surfaces canmore » be uniquely distributed and segmented in advanced patterns and often irregular shapes in order to minimize wavefront error across the pupil. The ultra-low-stress polysilicon and planarized upper layer allow designers to make larger and more complex micromirrors of varying shape and surface area within an array while maintaining uniform performance of optical surfaces. Powerful layout functions of the AutoCAD editor simplify the design of advanced micromirror arrays and make it possible to optimize devices according to the capabilities of the fabrication process. Micromirrors fabricated in this process have demonstrated a surface variance across the array from only 2{endash}3 nm to a worst case of roughly 25 nm while boasting active surface areas of 98{percent} or better. Combining the process planarization with a {open_quotes}planarized-by-design{close_quotes} approach will produce micromirror array surfaces that are limited in flatness only by the surface deposition roughness of the structural material. Ultimately, the combination of advanced process and layout capabilities have permitted the fabrication of highly optimized micromirror arrays for adaptive optics. {copyright} {ital 1999 American Institute of Physics.}« less

Ecology, physiology, and phylogeny of deep subsurface Sphingomonas sp.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fredrickson, Jim K.; Balkwill, David L.; Romine, Margaret F.

Several new species of the genus Sphingomonas including S. aromaticivorans, S. stygia, and S. subterranea that have the capacity for degrading a broad range of aromatic compounds including toluene, naphthalene, xylenes, p-cresol, fluorene, biphenyl, and dibenzothiophene, were isolated from deeply-buried (>200 m) sediments of the US Atlantic coastal plain (ACP). In S. aromaticivorans F199, many of the genes involved in the catabolism of these aromatic compounds are encoded on a 184-kb conjugative plasmid; some of the genes involved in aromatic catabolism are plasmid-encoded in the other strains as well. Members of the genus Sphingomonas were common among aerobic heterotrophic bacteriamore » cultured from ACP sediments and have been detected in deep subsurface environments elsewhere. The major source of organic carbon for heterotrophic metabolism in ACP deep aquifers is lignite that originated from plant material buried with the sediments. We speculate that the ability of the subsurface Sphingomonas strains to degrade a wide array of aromatic compounds represents an adaptation for utilization of sedimentary lignite. These and related subsurface Sphingomonas spp may play an important role in the transformation of sedimentary organic carbon in the aerobic and microaerobic regions of the deep aquifers of the ACP.« less

Laccase engineering: from rational design to directed evolution.

PubMed

Mate, Diana M; Alcalde, Miguel

2015-01-01

Laccases are multicopper oxidoreductases considered by many in the biotechonology field as the ultimate "green catalysts". This is mainly due to their broad substrate specificity and relative autonomy (they use molecular oxygen from air as an electron acceptor and they only produce water as by-product), making them suitable for a wide array of applications: biofuel production, bioremediation, organic synthesis, pulp biobleaching, textiles, the beverage and food industries, biosensor and biofuel cell development. Since the beginning of the 21st century, specific features of bacterial and fungal laccases have been exhaustively adapted in order to reach the industrial demands for high catalytic activity and stability in conjunction with reduced production cost. Among the goals established for laccase engineering, heterologous functional expression, improved activity and thermostability, tolerance to non-natural media (organic solvents, ionic liquids, physiological fluids) and resistance to different types of inhibitors are all challenges that have been met, while obtaining a more comprehensive understanding of laccase structure-function relationships. In this review we examine the most significant advances in this exciting research area in which rational, semi-rational and directed evolution approaches have been employed to ultimately convert laccases into high value-added biocatalysts. Copyright © 2014 Elsevier Inc. All rights reserved.

Key Aspects of a Sustainable Health Insurance System in Germany.

PubMed

Pelster, Matthias; Hagemann, Vera; Laporte Uribe, Franziska

2016-06-01

The main goals of health-care systems are to improve the health of the population they serve, respond to people's legitimate expectations, and offer fair financing. As a result, the health system in Germany is subject to continuous adaption as well as public and political discussions about its design. This paper analyzes the key challenges for the German health-care system and the underlying factors driving these challenges. We aim to identify possible solutions to put the German health-care system in a better position to face these challenges. We utilize a broad array of methods to answer these questions, including a review of the published and grey literature on health-care planning in Germany, semi-structured interviews with stakeholders in the system, and an online questionnaire. We find that the most urgent (and manageable) aspects that merit attention are holistic hospital planning, initiatives to increase (administrative) innovation in the health-care system, incentives to increase prevention, and approaches to increase analytical quality assurance. We found that hospital planning, innovation, quality control, and prevention, are considered to be the topics most in need of attention in the German health system.

Courting disaster: How diversification rate affects fitness under risk.

PubMed

Ratcliff, William C; Hawthorne, Peter; Libby, Eric

2015-01-01

Life is full of risk. To deal with this uncertainty, many organisms have evolved bet-hedging strategies that spread risk through phenotypic diversification. These rates of diversification can vary by orders of magnitude in different species. Here we examine how key characteristics of risk and organismal ecology affect the fitness consequences of variation in diversification rate. We find that rapid diversification is strongly favored when the risk faced has a wide spatial extent, with a single disaster affecting a large fraction of the population. This advantage is especially great in small populations subject to frequent disaster. In contrast, when risk is correlated through time, slow diversification is favored because it allows adaptive tracking of disasters that tend to occur in series. Naturally evolved diversification mechanisms in diverse organisms facing a broad array of environmental risks largely support these results. The theory presented in this article provides a testable ecological hypothesis to explain the prevalence of slow stochastic switching among microbes and rapid, within-clutch diversification strategies among plants and animals. © 2014 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Photodetector development at Fraunhofer IAF: From LWIR to SWIR operating from cryogenic close to room temperature

NASA Astrophysics Data System (ADS)

Daumer, V.; Gramich, V.; Müller, R.; Schmidt, J.; Rutz, F.; Stadelmann, T.; Wörl, A.; Rehm, R.

2017-02-01

Photodetectors in the non-visible region of the electromagnetic spectrum are essential for security, defense and space science as well as industrial and scientific applications. The research activities at Fraunhofer IAF cover a broad range in the infrared (IR) regime. Whereas short-wavelength IR (SWIR, <1.7 μm) detectors are realized by InGaAs/InP structures, InAs/GaSb type-II superlattice (T2SL) infrared detectors are developed for the spectral bands from mid- (MWIR, 3-5 μm) to long-wavelength IR (LWIR, 8-12 μm). We report on the extension of the superlattice empirical pseudopotential method (SEPM) to 300 K for the design of LWIR heterostructures for operation near room temperature. Recently, we have also adapted heterostructure concepts to our well established bi-spectral T2SL MWIR detector resulting in a dark current density below 2 × 10-9 A/cm2 for a cut-off wavelength close to 5 μm. Finally, we present first results obtained with a gated viewing system based on our InGaAs/InAlAs/InP avalanche photodiode arrays.

Ecology, physiology, and phylogeny of deep subsurface Sphingomonas sp.

PubMed

Fredrickson, J K; Balkwill, D L; Romine, M F; Shi, T

1999-10-01

Several new species of the genus Sphingomonas including S. aromaticivorans, S. stygia, and S. subterranea that have the capacity for degrading a broad range of aromatic compounds including toluene, naphthalene, xylenes, p-cresol, fluorene, biphenyl, and dibenzothiophene, were isolated from deeply-buried (>200 m) sediments of the US Atlantic coastal plain (ACP). In S. aromaticivorans F199, many of the genes involved in the catabolism of these aromatic compounds are encoded on a 184-kb conjugative plasmid; some of the genes involved in aromatic catabolism are plasmid-encoded in the other strains as well. Members of the genus Sphingomonas were common among aerobic heterotrophic bacteria cultured from ACP sediments and have been detected in deep subsurface environments elsewhere. The major source of organic carbon for heterotrophic metabolism in ACP deep aquifers is lignite that originated from plant material buried with the sediments. We speculate that the ability of the subsurface Sphingomonas strains to degrade a wide array of aromatic compounds represents an adaptation for utilization of sedimentary lignite. These and related subsurface Sphingomonas spp may play an important role in the transformation of sedimentary organic carbon in the aerobic and microaerobic regions of the deep aquifers of the ACP.

Characterization of the macrocyclase involved in the biosynthesis of RiPP cyclic peptides in plants.

PubMed

Chekan, Jonathan R; Estrada, Paola; Covello, Patrick S; Nair, Satish K

2017-06-20

Enzymes that can catalyze the macrocyclization of linear peptide substrates have long been sought for the production of libraries of structurally diverse scaffolds via combinatorial gene assembly as well as to afford rapid in vivo screening methods. Orbitides are plant ribosomally synthesized and posttranslationally modified peptides (RiPPs) of various sizes and topologies, several of which are shown to be biologically active. The diversity in size and sequence of orbitides suggests that the corresponding macrocyclases may be ideal catalysts for production of cyclic peptides. Here we present the biochemical characterization and crystal structures of the plant enzyme PCY1 involved in orbitide macrocyclization. These studies demonstrate how the PCY1 S9A protease fold has been adapted for transamidation, rather than hydrolysis, of acyl-enzyme intermediates to yield cyclic products. Notably, PCY1 uses an unusual strategy in which the cleaved C-terminal follower peptide from the substrate stabilizes the enzyme in a productive conformation to facilitate macrocyclization of the N-terminal fragment. The broad substrate tolerance of PCY1 can be exploited as a biotechnological tool to generate structurally diverse arrays of macrocycles, including those with nonproteinogenic elements.

Performance of a modified feedback loop adaptive array with TVRO satellite signals

NASA Technical Reports Server (NTRS)

Steadman, K.; Gupta, I. J.; Walton, E. K.

1990-01-01

The performance of an experimental adaptive antenna array system is evaluated using television-receive-only (TVRO) satellite signals. The experimental system is a sidelobe canceler with two auxiliary channels. Modified feedback loops are used to enhance the suppression of weak interfering signals. The modified feedback loops use two spatially separate antennas, each with an individual amplifier for each auxiliary channel. Thus, the experimental system uses five antenna elements. Instead of using five separate antennas, a reflector antenna with multiple feeds is used to receive signals from various TVRO satellites. The details of the earth station are given. It is shown that the experimental system can null up to two signals originating from interfering TVRO satellites while receiving the signals from a desired TVRO satellite.

Adaptive EAGLE dynamic solution adaptation and grid quality enhancement

NASA Technical Reports Server (NTRS)

Luong, Phu Vinh; Thompson, J. F.; Gatlin, B.; Mastin, C. W.; Kim, H. J.

1992-01-01

In the effort described here, the elliptic grid generation procedure in the EAGLE grid code was separated from the main code into a subroutine, and a new subroutine which evaluates several grid quality measures at each grid point was added. The elliptic grid routine can now be called, either by a computational fluid dynamics (CFD) code to generate a new adaptive grid based on flow variables and quality measures through multiple adaptation, or by the EAGLE main code to generate a grid based on quality measure variables through static adaptation. Arrays of flow variables can be read into the EAGLE grid code for use in static adaptation as well. These major changes in the EAGLE adaptive grid system make it easier to convert any CFD code that operates on a block-structured grid (or single-block grid) into a multiple adaptive code.

The CHARA array adaptive optics I: common-path optical and mechanical design, and preliminary on-sky results

NASA Astrophysics Data System (ADS)

Che, Xiao; Sturmann, Laszlo; Monnier, John D.; ten Brummelaar, Theo A.; Sturmann, Judit; Ridgway, Stephen T.; Ireland, Michael J.; Turner, Nils H.; McAlister, Harold A.

2014-07-01

The CHARA array is an optical interferometer with six 1-meter diameter telescopes, providing baselines from 33 to 331 meters. With sub-milliarcsecond angular resolution, its versatile visible and near infrared combiners offer a unique angle of studying nearby stellar systems by spatially resolving their detailed structures. To improve the sensitivity and scientific throughput, the CHARA array was funded by NSF-ATI in 2011 to install adaptive optics (AO) systems on all six telescopes. The initial grant covers Phase I of the AO systems, which includes on-telescope Wavefront Sensors (WFS) and non-common-path (NCP) error correction. Meanwhile we are seeking funding for Phase II which will add large Deformable Mirrors on telescopes to close the full AO loop. The corrections of NCP error and static aberrations in the optical system beyond the WFS are described in the second paper of this series. This paper describes the design of the common-path optical system and the on-telescope WFS, and shows the on-sky commissioning results.

Array analysis of electromagnetic radiation from radio transmitters for submarine communication

NASA Astrophysics Data System (ADS)

Füllekrug, Martin; Mezentsev, Andrew; Watson, Robert; Gaffet, Stéphane; Astin, Ivan; Evans, Adrian

2014-12-01

The array analyses used for seismic and infrasound research are adapted and applied here to the electromagnetic radiation from radio transmitters for submarine communication. It is found that the array analysis enables a determination of the slowness and the arrival azimuth of the wave number vectors associated with the electromagnetic radiation. The array analysis is applied to measurements of ˜20-24 kHz radio waves from transmitters for submarine communication with an array of 10 radio receivers distributed over an area of ˜1 km ×1 km. The observed slowness of the observed wave number vectors range from ˜2.7 ns/m to ˜4.1 ns/m, and the deviations between the expected arrival azimuths and the observed arrival azimuths range from ˜-9.7° to ˜14.5°. The experimental results suggest that it is possible to determine the locations of radio sources from transient luminous events above thunderclouds with an array of radio receivers toward detailed investigations of the electromagnetic radiation from sprites.

Comparison of candidate solar array maximum power utilization approaches. [for spacecraft propulsion

NASA Technical Reports Server (NTRS)

Costogue, E. N.; Lindena, S.

1976-01-01

A study was made of five potential approaches that can be utilized to detect the maximum power point of a solar array while sustaining operations at or near maximum power and without endangering stability or causing array voltage collapse. The approaches studied included: (1) dynamic impedance comparator, (2) reference array measurement, (3) onset of solar array voltage collapse detection, (4) parallel tracker, and (5) direct measurement. The study analyzed the feasibility and adaptability of these approaches to a future solar electric propulsion (SEP) mission, and, specifically, to a comet rendezvous mission. Such missions presented the most challenging requirements to a spacecraft power subsystem in terms of power management over large solar intensity ranges of 1.0 to 3.5 AU. The dynamic impedance approach was found to have the highest figure of merit, and the reference array approach followed closely behind. The results are applicable to terrestrial solar power systems as well as to other than SEP space missions.

Experimental Investigation of the Herschel-Quincke Tube Concept on the Honeywell TFE731-60

NASA Technical Reports Server (NTRS)

Smith, Jerome P.; Burdisso, Ricardo A.; Gerhold, Carl H. (Technical Monitor)

2002-01-01

This report summarizes the key results obtained by the Vibration and Acoustics Laboratories at Virginia Tech over the period from January 1999 to December 2000 on the project 'Investigation of an Adaptive Herschel-Quincke Tube Concept for the Reduction of Tonal and Broadband Noise from Turbofan Engines', funded by NASA Langley Research Center. The Herschel-Quincke (HQ) tube concept is a developing technique that consists of circumferential arrays of tubes around the duct. A fixed array of tubes is installed on the inlet duct of the Honeywell TFE731-60 engine. Two array designs are incorporated into the inlet treatment, each designed for a different circumferential mode order which is expected to be cut on in the duct. Far field and in-duct noise measurement data are presented which demonstrate the effectiveness of the HQ concept for array 1, array 2, and both operating simultaneously.

New customizable phased array UT instrument opens door for furthering research and better industrial implementation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dao, Gavin; Ginzel, Robert

2014-02-18

Phased array UT as an inspection technique in itself continues to gain wide acceptance. However, there is much room for improvement in terms of implementation of Phased Array (PA) technology for every unique NDT application across several industries (e.g. oil and petroleum, nuclear and power generation, steel manufacturing, etc.). Having full control of the phased array instrument and customizing a software solution is necessary for more seamless and efficient inspections, from setting the PA parameters, collecting data and reporting, to the final analysis. NDT researchers and academics also need a flexible and open platform to be able to control variousmore » aspects of the phased array process. A high performance instrument with advanced PA features, faster data rates, a smaller form factor, and capability to adapt to specific applications, will be discussed.« less

Development of 640 X 480 LWIR focal plane arrays

NASA Astrophysics Data System (ADS)

Shallcross, Frank V.; Meyerhofer, Dietrich; Dolny, Gary M.; Gilmartin, Harvey R.; Tower, John R.; Palfrey, Stephen L.

1992-08-01

The 640 X 480 MOS multiplexer developed for PtSi MWIR focal plane arrays has been adapted to LWIR operation. The multiplexer is very flexible and can be used in various operating modes. The MOS approach, with its high saturation capacity and low-temperature operating capability, is ideally suited for long-wavelength operation. In this paper applications of the multiplexer to IrSi Schottky detectors and SiGe heterojunction detectors are discussed.

The energy spectrum of cosmic rays above 1017.2 eV measured by the fluorescence detectors of the Telescope Array experiment in seven years

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2016-07-01

The Telescope Array (TA) experiment is the largest detector to observe ultra-high-energy cosmic rays in the northern hemisphere. The fluorescence detectors at two stations of TA are newly constructed and have now completed seven years of steady operation. One advantage of monocular analysis of the fluorescence detectors is a lower energy threshold for cosmic rays than that of other techniques like stereoscopic observations or coincidences with the surface detector array, allowing the measurement of an energy spectrum covering three orders of magnitude in energy. Analyzing data collected during those seven years, we report the energy spectrum of cosmic rays covering a broad range of energies above 1017.2eV measured by the fluorescence detectors and a comparison with previously published results.

The Structure and Agency Dilemma in Identity and Intercultural Communication Research

ERIC Educational Resources Information Center

Block, David

2013-01-01

Against a backdrop of rapid global transformations, the ever-increasing migration of people across nation-state borders and a wide array of language practices, applied linguists, and language and intercultural communication researchers in particular, often include identity as a key construct in their work. Most adopt a broadly poststructuralist…

A Review of Similarities between Domain-Specific Determinants of Four Health Behaviors among Adolescents

ERIC Educational Resources Information Center

Peters, Louk W. H.; Wiefferink, Carin H.; Hoekstra, Femke; Buijs, Goof J.; ten Dam, Geert T. M.; Paulussen, Theo G. W. M.

2009-01-01

Schools are overloaded with health promotion programs that, altogether, focus on a broad array of behavioral domains, including substance abuse, sexuality and nutrition. Although the specific content of programs varies according to the domain focus, programs usually address similar concepts: knowledge, attitudinal beliefs, social influences and…

Schools and Society: A Sociological Approach to Education, Third Edition

ERIC Educational Resources Information Center

Ballantine, Jeanne H., Ed.; Spade, Joan Z., Ed.

2007-01-01

This third edition, now published by Pine Forge Press, features original readings and article excerpts by leaders in the area of Sociology of Education. With a wide array of theoretical perspectives, a broad range of respected sources, and inclusion of both classic and contemporary studies, this comprehensive, integrated text addresses key issues…

Development of Relative Importance Values as Contribution Weights for Evaluating Human Wellbeing: An Ecosystem Services Example

EPA Science Inventory

The dependence of society on the flows, valuation and provisioning of various capital driven services is key to understanding and developing linkages to human wellbeing. By extension, decision makers need knowledge and an array of products that allow them to think more broadly a...

Messages Are Everywhere: Reading Perceptions, Habits, and Preferences of Undergraduates

ERIC Educational Resources Information Center

Nadelson, Louis S.; Villagómez, Amanda; Konkol, Danielle; Haskell, Chris; McCulley, Meleah; Campbell, Denise

2013-01-01

As society continues to evolve, so do the methods that are used for text-based communication. Electronic books, mobile phone text messaging, and an array of internet-based texts are now combined with traditional print forms of text, broadly expanding text-based communication. However, student perceptions of reading may still be limited to…

Legal Liability of School Board Members. Revised Edition.

ERIC Educational Resources Information Center

Leverett, E. Freeman

This booklet reviews a broad array of factors affecting the immunity of school board members from personal liability for the results of their official acts. Among the factors examined are the federal doctrine of limited immunity as it applies to state officials; the possible extension of absolute immunity to school boards; the conditions under…

IT Legislative and Regulatory Issues Agenda. Higher Education Information Technology Alliance

ERIC Educational Resources Information Center

National Association of State Universities and Land-Grant Colleges, 2004

2004-01-01

This document represents the higher education and library community's guiding public policy agenda on information technology (IT) for the current year. The Higher Education Information Technology (HEIT) Alliance is a coalition of 11 national higher education and library associations, whose members represent a broad array of stakeholders on college…

The Nature of Subjective Cognitive Complaints of Older Adults

ERIC Educational Resources Information Center

Newson, Rachel S.; Kemps, Eva B.

2006-01-01

The current study investigated the nature of subjective cognitive complaints of older adults in relation to a broad array of individual cognitive functions known to decline with age. A 60-item questionnaire was developed to examine: (1) whether older adults experience problems with these cognitive functions (problems with cognition); (2) the…

Factors affecting people's response to invasive species management

Treesearch

Paul H. Gobster

2011-01-01

Natural areas managers contend with an increasingly diverse array of invasive species in their mission to conserve the health and integrity of ecosystems under their charge. As users, nearby neighbours and de facto 'owners' of the lands where many significant natural areas reside, the public is often highly supportive of broad programme goals for management...

Toward a Public Toxicogenomics Capability for Supporting Predictive Toxicology: Survey of Current Resources and Chemical Indexing of Experiments in GEO and ArrayExpress

EPA Science Inventory

A publicly available toxicogenomics capability for supporting predictive toxicology and meta-analysis depends on availability of gene expression data for chemical treatment scenarios, the ability to locate and aggregate such information by chemical, and broad data coverage within...

Tribute: Remembering Albert Greve (1938-2011)

NASA Astrophysics Data System (ADS)

Baars, Jaap

2012-02-01

With the sudden death of Albert Greve on 13 June 2011, caused by a massive heart attack, the radio astronomy community lost a remarkable member, and many of us a very good friend. The career of Albert was characterized by a broad array of activities, all performed at a high level of professionalism and an enduring wit.

Fostering Students' Participation in Online Environments: Focus on Interaction, Communication and Problem Solving

ERIC Educational Resources Information Center

Zacharis, Nick Z.

2009-01-01

Rapid technological advances in the areas of telecommunications, computer technology and the Internet have made available to tutors and learners in the domain of online learning, a broad array of tools that provide the possibility to facilitate and enhance learning to higher levels of critical reflective thinking. Computer mediated communication…

Taking a Societal Sector Perspective on Youth Learning and Development

ERIC Educational Resources Information Center

McLaughlin, Milbrey; London, Rebecca A.

2013-01-01

A societal sector perspective looks to a broad array of actors and agencies responsible for creating the community contexts that affect youth learning and development. We demonstrate the efficacy of this perspective by describing the Youth Data Archive, which allows community partners to define issues affecting youth that transcend specific…

Simultaneous detection of multiple chemical residues in milk using broad-specifity antibodies in a hybrid immunosorbent assay

USDA-ARS?s Scientific Manuscript database

The wide array of applications using quantum dots (QDs) for detection of multiple analytes reflects the versatility of the technology. In this study, a novel immunoassay using 2 types of sensors (QDs and an enzyme) were simultaneously used for detecting multiple structurally different low-molecular...

Emerging research on real-time air pollution sensing with the United States Environmental Protection Agency, Office of Research and Development

EPA Science Inventory

Abstract: Air pollution research ranges broadly at the US EPA and includes the characterization of pollutant emissions from a wide array of sources, studying post-emission transport and transformation in the atmosphere, and evaluating the linkages between air pollution and advers...

Preparing School Leaders for a Changing World: Lessons from Exemplary Leadership Development Programs. School Leadership Study. Executive Summary

ERIC Educational Resources Information Center

Darling-Hammond, Linda; LaPointe, Michelle; Meyerson, Debra; Orr, Margaret Terry

2007-01-01

Contemporary school administrators play a daunting array of roles. They must be educational visionaries and change agents, instructional leaders, curriculum and assessment experts, budget analysts, facility managers, special program administrators, and community builders. New expectations for schools--that they successfully teach a broad range of…

Limits on radio emission from meteors using the MWA

NASA Astrophysics Data System (ADS)

Zhang, X.; Hancock, P.; Devillepoix, H. A. R.; Wayth, R. B.; Beardsley, A.; Crosse, B.; Emrich, D.; Franzen, T. M. O.; Gaensler, B. M.; Horsley, L.; Johnston-Hollitt, M.; Kaplan, D. L.; Kenney, D.; Morales, M. F.; Pallot, D.; Steele, K.; Tingay, S. J.; Trott, C. M.; Walker, M.; Williams, A.; Wu, C.; Ji, Jianghui; Ma, Yuehua

2018-07-01

Recently, low-frequency, broad-band radio emission has been observed accompanying bright meteors by the Long Wavelength Array (LWA). The broad-band spectra between 20 and 60 MHz were captured for several events, while the spectral index (dependence of flux density on frequency, with Sν ∝ να) was estimated to be -4 ± 1 during the peak of meteor afterglows. Here we present a survey of meteor emission and other transient events using the Murchison Wide Field Array (MWA) at 72-103 MHz. In our 322 h survey, down to a 5σ detection threshold of 3.5 Jy beam-1, no transient candidates were identified as intrinsic emission from meteors. We derived an upper limit of -3.7 (95 per cent confidence limit) on the spectral index in our frequency range. We also report detections of other transient events, such as reflected FM broadcast signals from small satellites, conclusively demonstrating the ability of the MWA to detect and track space debris on scales as small as 0.1 m in low Earth orbits.

Family Adaptation to Relocation: An Empirical Analysis of Family Stressors, Adaptive Resources, and Sense of Coherence

DTIC Science & Technology

1989-07-01

825. Lazarus , R. S., & Folkman , S. (1984). Stress, appraisal, and coping. New York: Springer. mcCuIbin, H. I., & Lavee, Y . (1986). Strengthenirg Army...Soirani, 1988; Lazarus & Folkman , 1984; Mckbbin & Patterson, 1983), family adaptation was defined broadly as a crmposite of the overall adjustment of...ongr- y of expectations that members and spouses had prior to arrival in West Germany with their actual experiences since arrival (Alpha: Members = .91

Antibody Protein Array Analysis of the Tear Film Cytokines

PubMed Central

Li, Shimin; Sack, Robert; Vijmasi, Trinka; Sathe, Sonal; Beaton, Ann; Quigley, David; Gallup, Marianne; McNamara, Nancy A.

2013-01-01

Purpose Many bioactive proteins including cytokines are reported to increase in dry eye disease although the specific profile and concentration of inflammatory mediators varies considerably from study to study. In part this variability results from inherent difficulties in quantifying low abundance proteins in a limited sample volume using relatively low sensitivity dot ELISA methods. Additional complexity comes with the use of pooled samples collected using a variety of techniques and intrinsic variation in the diurnal pattern of individual tear proteins. The current study describes a recent advance in the area of proteomics that has allowed the identification of dozens of low abundance proteins in human tear samples. Methods Commercially available stationary phase antibody protein arrays were adapted to improve suitability for use in small volume biological fluid analysis with particular emphasis on tear film proteomics. Arrays were adapted to allow simultaneous screening for a panel of inflammatory cytokines in low volume tear samples collected from individual eyes. Results A preliminary study comparing tear array results in a small population of Sjögren’s syndrome patients was conducted. The multiplex microplate array assays of cytokines in tear fluid present an unanticipated challenge due to the unique nature of tear fluid. The presence of factors that exhibit an affinity for plastic, capture antibodies and IgG and create a complex series of matrix effects profoundly impacting the reliability of dot ELISA, including with elevated levels of background reactivity and reduction in capacity to bind targeted protein. Conclusions Preliminary results using tears collected from patients with Sjögren’s syndrome reveal methodological advantages of protein array technology and support the concept that autoimmune-mediated dry eye disease has an inflammatory component. They also emphasize the inherent difficulties one can face when interpreting the results of micro-well arrays that result from blooming effects, matrix effects, image saturation and cross-talk between capture and probe antibodies that can greatly reduce signal-to-noise and limit the ability to obtain meaningful results. PMID:18677223

Adaptive Sampling in Autonomous Marine Sensor Networks

DTIC Science & Technology

2006-06-01

Analog Processing Section A high-performance preamplifier with low noise characteristics is vital to obtaining quality sonar data. The preamplifier ...research assistantships through the Generic Ocean Array Technology Sonar (GOATS) project, contract N00014-97-1-0202 and contract N00014-05-G-0106 Delivery...Formation Behavior ..................................... 60 5 An AUV Intelligent Sensor for Real-Time Adaptive Sensing 63 5.1 A Logical Sonar Sensor

[Development of a portable mid-infrared rapid analyzer for oil concentration in water based on MEMS linear sensor array].

PubMed

Gao, Zhi-fan; Zeng, Li-bo; Shi, Lei; Li, Kai; Yang, Yuan-zhou; Wu, Qiong-shui

2014-06-01

Aiming at the existing problems such as weak environmental adaptability, low analytic efficiency and poor measuring repeatability in the traditional spectral oil analyzers, the present paper designed a portable mid-infrared rapid analyzer for oil concentration in water. To reduce the volume of the instrument, the non-symmetrical folding M-type Czerny-Turner optical structure was adopted in the core optical path. With a periodically rotating chopper, controlled by digital PID algorithm, applied for infrared light modulation, the modulating accuracy reached ±0.5%. Different from traditional grating-scanning spectrophotometers, this instrument used a fixed grating for light dispersion and avoided rotating error in the course of the measuring procedures. A new-type MEMS infrared linear sensor array was applied for modulated spectral signals detection, which improved the measuring efficiency remarkably. Optical simulation and experimental results indicate that the spectral range is 2 800 - 3 200 cm(-1), the spectral resolution is 6 cm(-1) (@3 130 cm(-1)), and the signal to noise ratio is up to 5 200 : 1. The acquisition time is 13 milliseconds per spectrogram, and the standard deviation of absorbance is less than 3 x 10(-3). These performances meet the standards of oil concentration measurements perfectly. Compared with traditional infrared spectral analyzers for oil concentration, the instrument demonstrated in this paper has many advantages such as smaller size, more efficiency, higher precision, and stronger vibration & moisture isolation. In addition, the proposed instrument is especially suitable for the environmental monitoring departments to implement real-time measurements in the field for oil concentration in water, hence it has broad prospects of application in the field of water quality monitoring.

Uniform circular array for structural health monitoring of composite structures

NASA Astrophysics Data System (ADS)

Stepinski, Tadeusz; Engholm, Marcus

2008-03-01

Phased array with all-azimuth angle coverage would be extremely useful in structural health monitoring (SHM) of planar structures. One method to achieve the 360° coverage is to use uniform circular arrays (UCAs). In this paper we present the concept of UCA adapted for SHM applications. We start from a brief presentation of UCA beamformers based on the principle of phase mode excitation. UCA performance is illustrated by the results of beamformer simulations performed for the narrowband and wideband ultrasonic signals. Preliminary experimental results obtained with UCA used for the reception of ultrasonic signals propagating in an aluminum plate are also presented.

User-Adaptable Microcomputer Graphics Software for Life Science Instruction. Final Project Report.

ERIC Educational Resources Information Center

Spain, James D.

The objectives of the SUMIT project was to develop, evaluate, and disseminate 20 course modules (microcomputer programs) for instruction in general biology and ecology. To encourage broad utilization, the programs were designed for the Apple II microcomputer and written in Applesoft Basic with a user-adaptable format. Each package focused on a key…

Adaptable, Deployable Entry and Placement Technology (ADEPT) for Future Mars Missions

NASA Technical Reports Server (NTRS)

Wercinski, P.; Venkatapathy, E.; Gage, P.; Prabhu, D.; Smith, B.; Cassell, A.; Yount, B.; Allen, G.

2013-01-01

The concept of a mechanically deploy- able hypersonic decelerator, developed initially for high mass (40 MT) human Mars missions, is currently funded by OCT for technology maturation. The ADEPT (Adaptive, Deployable Entry and Placement Technology) project has broad, game-changing applicability to in situ science missions to Venus, Mars, and the Outer Planets.

MSAT-X phased array antenna adaptions to airborne applications

NASA Technical Reports Server (NTRS)

Sparks, C.; Chung, H. H.; Peng, S. Y.

1988-01-01

The Mobile Satellite Experiment (MSAT-X) phased array antenna is being modified to meet future requirements. The proposed system consists of two high gain antennas mounted on each side of a fuselage, and a low gain antenna mounted on top of the fuselage. Each antenna is an electronically steered phased array based on the design of the MSAT-X antenna. A beamforming network is connected to the array elements via coaxial cables. It is essential that the proposed antenna system be able to provide an adequate communication link over the required space coverage, which is 360 degrees in azimuth and from 20 degrees below the horizon to the zenith in elevation. Alternative design concepts are suggested. Both open loop and closed loop backup capabilities are discussed. Typical antenna performance data are also included.

Inspection of aircraft fastener holes using a conically shaped multi-element phased array probe

NASA Astrophysics Data System (ADS)

Selman, J. J.; Miller, J. T.; Moles, M. D. C.; Dupuis, O.; Herzog, P. G.

2002-05-01

A novel inspection technique is described using phased ultrasonic arrays to detect faying surface cracks in the first layer around the base of a fastener hole with fasteners installed. A unique phased array probe incorporates a matrix of ultrasonic elements arranged in a conical configuration encircling the fastener head. This arrangement permits deflection of the ultrasonic beam in three dimensions, and adapts to different hole diameters and skin thickness. Full circumferential scans are performed using a pre-programmed sequence of phased array focal laws. The inspection method uses pulse-echo at a variety of angles incident on the crack to thoroughly cover the fastener hole and surrounding area, and is designed to detect cracks as small as 0.030″ in length.

Alternative Optimizations of X-ray TES Arrays: Soft X-rays, High Count Rates, and Mixed-Pixel Arrays

NASA Technical Reports Server (NTRS)

Kilbourne, C. A.; Bandler, S. R.; Brown, A.-D.; Chervenak, J. A.; Figueroa-Feliciano, E.; Finkbeiner, F. M.; Iyomoto, N.; Kelley, R. L.; Porter, F. S.; Smith, S. J.

2007-01-01

We are developing arrays of superconducting transition-edge sensors (TES) for imaging spectroscopy telescopes such as the XMS on Constellation-X. While our primary focus has been on arrays that meet the XMS requirements (of which, foremost, is an energy resolution of 2.5 eV at 6 keV and a bandpass from approx. 0.3 keV to 12 keV), we have also investigated other optimizations that might be used to extend the XMS capabilities. In one of these optimizations, improved resolution below 1 keV is achieved by reducing the heat capacity. Such pixels can be based on our XMS-style TES's with the separate absorbers omitted. These pixels can added to an array with broadband response either as a separate array or interspersed, depending on other factors that include telescope design and science requirements. In one version of this approach, we have designed and fabricated a composite array of low-energy and broad-band pixels to provide high spectral resolving power over a broader energy bandpass than could be obtained with a single TES design. The array consists of alternating pixels with and without overhanging absorbers. To explore optimizations for higher count rates, we are also optimizing the design and operating temperature of pixels that are coupled to a solid substrate. We will present the performance of these variations and discuss other optimizations that could be used to enhance the XMS or enable other astrophysics experiments.

Certified dual-corrected radiation patterns of phased antenna arrays by offline–online order reduction of finite-element models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sommer, A., E-mail: a.sommer@lte.uni-saarland.de; Farle, O., E-mail: o.farle@lte.uni-saarland.de; Dyczij-Edlinger, R., E-mail: edlinger@lte.uni-saarland.de

2015-10-15

This paper presents a fast numerical method for computing certified far-field patterns of phased antenna arrays over broad frequency bands as well as wide ranges of steering and look angles. The proposed scheme combines finite-element analysis, dual-corrected model-order reduction, and empirical interpolation. To assure the reliability of the results, improved a posteriori error bounds for the radiated power and directive gain are derived. Both the reduced-order model and the error-bounds algorithm feature offline–online decomposition. A real-world example is provided to demonstrate the efficiency and accuracy of the suggested approach.

High channel density wavelength division multiplexer with defined diffracting means positioning

DOEpatents

Jannson, Tomasz P.; Jannson, Joanna L.; Yeung, Peter C.

1990-01-01

A wavelength division multiplexer/demultiplexer having optical path lengths between a fiber array and a Fourier transform lens, and between a dispersion grating and the lens equal to the focal length of the lens. The optical path lengths reduce losses due to angular acceptance mismatch in the multiplexer. Close orientation of the fiber array about the optical axis and the use of a holographic dispersion grating reduces other losses in the system. Multi-exposure holographic dispersion gratings enable the multiplexer/demultiplexer for extremely broad-band simultaneous transmission and reflection operation. Individual Bragg plane sets recorded in the grating are dedicated to and operate efficiently on discrete wavelength ranges.

Evaluation of early antimicrobial therapy adaptation guided by the BetaLACTA® test: a case-control study.

PubMed

Garnier, Marc; Rozencwajg, Sacha; Pham, Tài; Vimont, Sophie; Blayau, Clarisse; Hafiani, Mehdi; Fulgencio, Jean-Pierre; Bonnet, Francis; Mainardi, Jean-Luc; Arlet, Guillaume; Fartoukh, Muriel; Gallah, Salah; Quesnel, Christophe

2017-06-28

Rapid diagnostic tests detecting microbial resistance are needed for limiting the duration of inappropriateness of empirical antimicrobial therapy (EAT) in intensive care unit patients, besides reducing the use of broad-spectrum antibiotics. We hypothesized that the betaLACTA® test (BLT) could lead to early increase in the adequacy of antimicrobial therapy. This was a case-control study. Sixty-one patients with BLT-guided adaptation of EAT were prospectively included, and then matched with 61 "controls" having similar infection characteristics (community or hospital-acquired, and source of infection), in whom EAT was conventionally adapted to antibiogram results. Endpoints were to compare the proportion of appropriate (primary endpoint) and optimal (secondary endpoint) antimicrobial therapies with each of the two strategies, once microbiological sample culture results were available. Characteristics of patients, infections and EAT at inclusion were similar between groups. Nine early escalations of EAT occurred in the BLT-guided adaptation group, reaching 98% appropriateness vs. 77% in the conventional adaptation group (p < 0.01). The BLT reduced the time until escalation of an inappropriate EAT from 50.5 (48-73) to 27 (24-28) hours (p < 0.01). Seventeen early de-escalations occurred in the BLT-guided adaptation group, compared to one in the conventional adaptation group, reducing patients' exposure to broad-spectrum beta-lactam such as carbapenems. In multivariate analysis, use of the BLT was strongly associated with early appropriate (OR = 18 (3.4-333.8), p = 0.006) and optimal (OR = 35.5 (9.6-231.9), p < 0.001) antimicrobial therapies. Safety parameters were similar between groups. Our study suggests that a BLT-guided adaptation strategy may allow early beta-lactam adaptation from the first 24 hours following the beginning of sepsis management.

Adaptive jammer nulling in EHF communications satellites

NASA Astrophysics Data System (ADS)

Bhagwan, Jai; Kavanagh, Stephen; Yen, J. L.

A preliminary investigation is reviewed concerning adaptive null steering multibeam uplink receiving system concepts for future extremely high frequency communications satellites. Primary alternatives in the design of the uplink antenna, the multibeam adaptive nulling receiver, and the processing algorithm and optimization criterion are discussed. The alternatives are phased array, lens or reflector antennas, nulling at radio frequency or an intermediate frequency, wideband versus narrowband nulling, and various adaptive nulling algorithms. A primary determinant of the hardware complexity is the receiving system architecture, which is described for the alternative antenna and nulling concepts. The final concept chosen will be influenced by the nulling performance requirements, cost, and technological readiness.

Digitally Controlled Slot Coupled Patch Array

NASA Technical Reports Server (NTRS)

D'Arista, Thomas; Pauly, Jerry

2010-01-01

A four-element array conformed to a singly curved conducting surface has been demonstrated to provide 2 dB axial ratio of 14 percent, while maintaining VSWR (voltage standing wave ratio) of 2:1 and gain of 13 dBiC. The array is digitally controlled and can be scanned with the LMS Adaptive Algorithm using the power spectrum as the objective, as well as the Direction of Arrival (DoA) of the beam to set the amplitude of the power spectrum. The total height of the array above the conducting surface is 1.5 inches (3.8 cm). A uniquely configured microstrip-coupled aperture over a conducting surface produced supergain characteristics, achieving 12.5 dBiC across the 2-to-2.13- GHz and 2.2-to-2.3-GHz frequency bands. This design is optimized to retain VSWR and axial ratio across the band as well. The four elements are uniquely configured with respect to one another for performance enhancement, and the appropriate phase excitation to each element for scan can be found either by analytical beam synthesis using the genetic algorithm with the measured or simulated far field radiation pattern, or an adaptive algorithm implemented with the digitized signal. The commercially available tuners and field-programmable gate array (FPGA) boards utilized required precise phase coherent configuration control, and with custom code developed by Nokomis, Inc., were shown to be fully functional in a two-channel configuration controlled by FPGA boards. A four-channel tuner configuration and oscilloscope configuration were also demonstrated although algorithm post-processing was required.

Adaptation in CRISPR-Cas Systems.

PubMed

Sternberg, Samuel H; Richter, Hagen; Charpentier, Emmanuelle; Qimron, Udi

2016-03-17

Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins constitute an adaptive immune system in prokaryotes. The system preserves memories of prior infections by integrating short segments of foreign DNA, termed spacers, into the CRISPR array in a process termed adaptation. During the past 3 years, significant progress has been made on the genetic requirements and molecular mechanisms of adaptation. Here we review these recent advances, with a focus on the experimental approaches that have been developed, the insights they generated, and a proposed mechanism for self- versus non-self-discrimination during the process of spacer selection. We further describe the regulation of adaptation and the protein players involved in this fascinating process that allows bacteria and archaea to harbor adaptive immunity. Copyright © 2016 Elsevier Inc. All rights reserved.

The Trans-Pacific Partnership: Is It Everything We Feared for Health?

PubMed

Labonté, Ronald; Schram, Ashley; Ruckert, Arne

2016-04-17

Negotiations surrounding the Trans-Pacific Partnership (TPP) trade and investment agreement have recently concluded. Although trade and investment agreements, part of a broader shift to global economic integration, have been argued to be vital to improved economic growth, health, and general welfare, these agreements have increasingly come under scrutiny for their direct and indirect health impacts. We conducted a prospective health impact analysis to identify and assess a selected array of potential health risks of the TPP. We adapted the standard protocol for Health impact assessments (HIAs) (screening, scoping, and appraisal) to our aim of assessing potential health risks of trade and investment policy, and selected a health impact review methodology. This methodology is used to create a summary estimation of the most significant impacts on health of a broad policy or cluster of policies, such as a comprehensive trade and investment agreement. Our analysis shows that there are a number of potentially serious health risks associated with the TPP, and details a range of policy implications for the health sector. Of particular focus are the potential implications of changes to intellectual property rights (IPRs), sanitary and phytosanitary measures (SPS), technical barriers to trade (TBT), investor-state dispute settlement (ISDS), and regulatory coherence provisions on a range of issues, including access to medicines and health services, tobacco and alcohol control, diet-related health, and domestic health policy-making. We provide a list of policy recommendations to mitigate potential health risks associated with the TPP, and suggest that broad public consultations, including on the health risks of trade and investment agreements, should be part of all trade negotiations. © 2016 by Kerman University of Medical Sciences

The Trans-Pacific Partnership: Is It Everything We Feared for Health?

PubMed Central

Labonté, Ronald; Schram, Ashley; Ruckert, Arne

2016-01-01

Background: Negotiations surrounding the Trans-Pacific Partnership (TPP) trade and investment agreement have recently concluded. Although trade and investment agreements, part of a broader shift to global economic integration, have been argued to be vital to improved economic growth, health, and general welfare, these agreements have increasingly come under scrutiny for their direct and indirect health impacts. Methods: We conducted a prospective health impact analysis to identify and assess a selected array of potential health risks of the TPP. We adapted the standard protocol for Health impact assessments (HIAs) (screening, scoping, and appraisal) to our aim of assessing potential health risks of trade and investment policy, and selected a health impact review methodology. This methodology is used to create a summary estimation of the most significant impacts on health of a broad policy or cluster of policies, such as a comprehensive trade and investment agreement. Results: Our analysis shows that there are a number of potentially serious health risks associated with the TPP, and details a range of policy implications for the health sector. Of particular focus are the potential implications of changes to intellectual property rights (IPRs), sanitary and phytosanitary measures (SPS), technical barriers to trade (TBT), investor-state dispute settlement (ISDS), and regulatory coherence provisions on a range of issues, including access to medicines and health services, tobacco and alcohol control, diet-related health, and domestic health policy-making. Conclusion: We provide a list of policy recommendations to mitigate potential health risks associated with the TPP, and suggest that broad public consultations, including on the health risks of trade and investment agreements, should be part of all trade negotiations. PMID:27694662

Image-guided ultrasound phased arrays are a disruptive technology for non-invasive therapy

NASA Astrophysics Data System (ADS)

Hynynen, Kullervo; Jones, Ryan M.

2016-09-01

Focused ultrasound offers a non-invasive way of depositing acoustic energy deep into the body, which can be harnessed for a broad spectrum of therapeutic purposes, including tissue ablation, the targeting of therapeutic agents, and stem cell delivery. Phased array transducers enable electronic control over the beam geometry and direction, and can be tailored to provide optimal energy deposition patterns for a given therapeutic application. Their use in combination with modern medical imaging for therapy guidance allows precise targeting, online monitoring, and post-treatment evaluation of the ultrasound-mediated bioeffects. In the past there have been some technical obstacles hindering the construction of large aperture, high-power, densely-populated phased arrays and, as a result, they have not been fully exploited for therapy delivery to date. However, recent research has made the construction of such arrays feasible, and it is expected that their continued development will both greatly improve the safety and efficacy of existing ultrasound therapies as well as enable treatments that are not currently possible with existing technology. This review will summarize the basic principles, current statures, and future potential of image-guided ultrasound phased arrays for therapy.

High Sensitivity Long-Wavelength Infrared QWIP Focal Plane Array Based Instrument for Remote Sensing of Icy Satellites

NASA Technical Reports Server (NTRS)

Gunapala, S.; Bandara, S.; Ivanov, A.

2003-01-01

GaAs based Quantum Well Infrared Photodetector (QWIP) technology has shown remarkable success in advancing low cost, highly uniform, high-operability, large format multi-color focal plane arrays. QWIPs afford greater flexibility than the usual extrinsically doped semiconductor IR detectors. The wavelength of the peak response and cutoff can be continuously tailored over a range wide enough to enable light detection at any wavelength range between 6 and 20 micron. The spectral band-width of these detectors can be tuned from narrow (Deltalambda/lambda is approximately 10%) to wide (Deltalambda/lambda is approximately 40%) allowing various applications. Furthermore, QWIPs offer low cost per pixel and highly uniform large format focal plane arrays due to mature GaAs/AlGaAs growth and processing technologies. The other advantages of GaAs/AlGaAs based QWIPS are higher yield, lower l/f noise and radiation hardness (1.5 Mrad). In this presentation, we will discuss our recent demonstrations of 640x512 pixel narrow-band, broad-band, multi-band focal plane arrays, and the current status of the development of 1024x1024 pixel long-wavelength infrared QWIP focal plane arrays.

Image-guided ultrasound phased arrays are a disruptive technology for non-invasive therapy.

PubMed

Hynynen, Kullervo; Jones, Ryan M

2016-09-07

Focused ultrasound offers a non-invasive way of depositing acoustic energy deep into the body, which can be harnessed for a broad spectrum of therapeutic purposes, including tissue ablation, the targeting of therapeutic agents, and stem cell delivery. Phased array transducers enable electronic control over the beam geometry and direction, and can be tailored to provide optimal energy deposition patterns for a given therapeutic application. Their use in combination with modern medical imaging for therapy guidance allows precise targeting, online monitoring, and post-treatment evaluation of the ultrasound-mediated bioeffects. In the past there have been some technical obstacles hindering the construction of large aperture, high-power, densely-populated phased arrays and, as a result, they have not been fully exploited for therapy delivery to date. However, recent research has made the construction of such arrays feasible, and it is expected that their continued development will both greatly improve the safety and efficacy of existing ultrasound therapies as well as enable treatments that are not currently possible with existing technology. This review will summarize the basic principles, current statures, and future potential of image-guided ultrasound phased arrays for therapy.

High-density functional-RNA arrays as a versatile platform for studying RNA-based interactions.

PubMed

Phillips, Jack O; Butt, Louise E; Henderson, Charlotte A; Devonshire, Martin; Healy, Jess; Conway, Stuart J; Locker, Nicolas; Pickford, Andrew R; Vincent, Helen A; Callaghan, Anastasia J

2018-05-28

We are just beginning to unravel the myriad of interactions in which non-coding RNAs participate. The intricate RNA interactome is the foundation of many biological processes, including bacterial virulence and human disease, and represents unexploited resources for the development of potential therapeutic interventions. However, identifying specific associations of a given RNA from the multitude of possible binding partners within the cell requires robust high-throughput systems for their rapid screening. Here, we present the first demonstration of functional-RNA arrays as a novel platform technology designed for the study of such interactions using immobilized, active RNAs. We have generated high-density RNA arrays by an innovative method involving surface-capture of in vitro transcribed RNAs. This approach has significant advantages over existing technologies, particularly in its versatility in regards to binding partner character. Indeed, proof-of-principle application of RNA arrays to both RNA-small molecule and RNA-RNA pairings is demonstrated, highlighting their potential as a platform technology for mapping RNA-based networks and for pharmaceutical screening. Furthermore, the simplicity of the method supports greater user-accessibility over currently available technologies. We anticipate that functional-RNA arrays will find broad utility in the expanding field of RNA characterization.

Design, Fabrication and Characterization of A Bi-Frequency Co-Linear Array

PubMed Central

Wang, Zhuochen; Li, Sibo; Czernuszewicz, Tomasz J; Gallippi, Caterina M.; Liu, Ruibin; Geng, Xuecang

2016-01-01

Ultrasound imaging with high resolution and large penetration depth has been increasingly adopted in medical diagnosis, surgery guidance, and treatment assessment. Conventional ultrasound works at a particular frequency, with a −6 dB fractional bandwidth of ~70 %, limiting the imaging resolution or depth of field. In this paper, a bi-frequency co-linear array with resonant frequencies of 8 MHz and 20 MHz was investigated to meet the requirements of resolution and penetration depth for a broad range of ultrasound imaging applications. Specifically, a 32-element bi-frequency co-linear array was designed and fabricated, followed by element characterization and real-time sectorial scan (S-scan) phantom imaging using a Verasonics system. The bi-frequency co-linear array was tested in four different modes by switching between low and high frequencies on transmit and receive. The four modes included the following: (1) transmit low, receive low, (2) transmit low, receive high, (3) transmit high, receive low, (4) transmit high, receive high. After testing, the axial and lateral resolutions of all modes were calculated and compared. The results of this study suggest that bi-frequency co-linear arrays are potential aids for wideband fundamental imaging and harmonic/sub-harmonic imaging. PMID:26661069

Image-guided ultrasound phased arrays are a disruptive technology for non-invasive therapy

PubMed Central

Hynynen, Kullervo; Jones, Ryan M.

2016-01-01

Focused ultrasound offers a non-invasive way of depositing acoustic energy deep into the body, which can be harnessed for a broad spectrum of therapeutic purposes, including tissue ablation, the targeting of therapeutic agents, and stem cell delivery. Phased array transducers enable electronic control over the beam geometry and direction, and can be tailored to provide optimal energy deposition patterns for a given therapeutic application. Their use in combination with modern medical imaging for therapy guidance allows precise targeting, online monitoring, and post-treatment evaluation of the ultrasound-mediated bioeffects. In the past there have been some technical obstacles hindering the construction of large aperture, high-power, densely-populated phased arrays and, as a result, they have not been fully exploited for therapy delivery to date. However, recent research has made the construction of such arrays feasible, and it is expected that their continued development will both greatly improve the safety and efficacy of existing ultrasound therapies as well as enable treatments that are not currently possible with existing technology. This review will summarize the basic principles, current statures, and future potential of image-guided ultrasound phased arrays for therapy. PMID:27494561

Micro-dressing of a carbon nanotube array with MoS2 gauze

NASA Astrophysics Data System (ADS)

Lim, Sharon Xiaodai; Woo, Kah Whye; Ng, Junju; Lu, Junpeng; Kwang, Siu Yi; Zhang, Zheng; Tok, Eng Soon; Sow, Chorng-Haur

2015-10-01

Few-layer MoS2 film has been successfully assembled over an array of CNTs. Using different focused laser beams with different wavelengths, site selective patterning of either the MoS2 film or the supporting CNT array is achieved. This paves the way for applications and investigations into the fundamental properties of the hybrid MoS2/CNT material with a controlled architecture. Through Raman mapping, straining and electron doping of the MoS2 film as a result of interaction with the supporting CNT array are detected. The role of the MoS2 film was further emphasized with a lower work function being detected from Ultra-violet Photoelectron Spectrsocopy (UPS) measurements of the hybrid material, compared to the CNT array. The effect of the changes in the work function was illustrated through the optoelectronic behavior of the hybrid material. At 0 V, 3.49 nA of current is measured upon illuminating the sample with a broad laser beam emitting laser light with a wavelength of 532 nm. With a strong response to external irradiation of different wavelengths, and changes to the power of the excitation source, the hybrid material has shown potential for applications in optoelectronic devices.

Generation of Custom DSP Transform IP Cores: Case Study Walsh-Hadamard Transform

DTIC Science & Technology

2002-09-01

mathematics and hardware design What I know: Finite state machine Pipelining Systolic array … What I know: Linear algebra Digital signal processing...state machine Pipelining Systolic array … What I know: Linear algebra Digital signal processing Adaptive filter theory … A math guy A hardware engineer...Synthesis Technology Libary Bit-width (8) HF factor (1,2,3,6) VF factor (1,2,4, ... 32) Xilinx FPGA Place&Route Xilinx FPGA Place&Route Performance

Semantically Aware Foundation Environment (SAFE) for Clean-Slate Design of Resilient, Adaptive Secure Hosts (CRASH)

DTIC Science & Technology

2016-02-01

system consists of a high-fidelity hardware simulation using field programmable gate arrays (FPGAs), with a set of runtime services (ConcreteWare...perimeter protection, patch, and pray” is not aligned with the threat. Programmers will not bail us out of this situation (by writing defect free code...hosted on a Field Programmable Gate Array (FPGA), with a set of runtime services (concreteware) running on the hardware. Secure applications can be

Compressive Channel Estimation and Tracking for Large Arrays in mm Wave Picocells

DTIC Science & Technology

2014-01-01

abling sophisticated adaptation, including frequency-selective spatiotemporal processing (e.g., per subcarrier beamforming in OFDM systems). This approach...subarrays are certainly required for more advanced functionalities such as multiuser MIMO [17], spatial multiplexing [18], [19], [20], [21], [22], and...case, a regu- larly spaced 2D array), an estimate of the N2t,1D × N2r,1D MIMO channel matrix H can be efficiently arrived at by estimating the spatial

Control of complex components with Smart Flexible Phased Arrays.

PubMed

Casula, O; Poidevin, C; Cattiaux, G; Dumas, Ph

2006-12-22

The inspection is mainly performed in contact with ultrasonic wedge transducers; However, the shape cannot fit the changing geometries of components (butt weld, nozzle, elbow). The variable thickness of the coupling layer, between the wedge and the local surface, leads to beam distortions and losses of sensitivity. Previous studies have shown that these two phenomena contribute to reduce the inspection performances leading to shadow area, split beam.... Flexible phased arrays have been developed to fit the complex profile and improve such controls. The radiating surface is composed with independent piezoelectric elements mechanically assembled and a profilometer, embedded in the transducer, measures the local distortion. The computed shape is used by an algorithm to compute in real-time the adapted delay laws compensating the distortions of 2D or 3D profiles. Those delay laws are transferred to the real-time UT acquisition system, which applies them to the piezoelectric elements. This self-adaptive process preserves, during the scanning, the features of the focused beam (orientation and focal depth) in the specimen. To validate the concept of the Smart Flexible Phased Array Transducer, prototypes have been integrated to detect flaws machined in mock-ups with realistic irregular 2D and 3D shapes. Inspections have been carried out on samples showing the enhancement performances of the "Smart Flexible Phased Array" and validating the mechanical and acoustical behaviors of these probes.

Expanding Coherent Array Processing to Larger Apertures Using Empirical Matched Field Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ringdal, F; Harris, D B; Kvaerna, T

2009-07-23

We have adapted matched field processing, a method developed in underwater acoustics to detect and locate targets, to classify transient seismic signals arising from mining explosions. Matched field processing, as we apply it, is an empirical technique, using observations of historic events to calibrate the amplitude and phase structure of wavefields incident upon an array aperture for particular repeating sources. The objective of this project is to determine how broadly applicable the method is and to understand the phenomena that control its performance. We obtained our original results in distinguishing events from ten mines in the Khibiny and Olenegorsk miningmore » districts of the Kola Peninsula, for which we had exceptional ground truth information. In a cross-validation test, some 98.2% of 549 explosions were correctly classified by originating mine using just the Pn observations (2.5-12.5 Hz) on the ARCES array at ranges from 350-410 kilometers. These results were achieved despite the fact that the mines are as closely spaced as 3 kilometers. Such classification performance is significantly better than predicted by the Rayleigh limit. Scattering phenomena account for the increased resolution, as we make clear in an analysis of the information carrying capacity of Pn under two alternative propagation scenarios: free-space propagation and propagation with realistic (actually measured) spatial covariance structure. The increase in information capacity over a wide band is captured by the matched field calibrations and used to separate explosions from very closely-spaced sources. In part, the improvement occurs because the calibrations enable coherent processing at frequencies above those normally considered coherent. We are investigating whether similar results can be expected in different regions, with apertures of increasing scale and for diffuse seismicity. We verified similar performance with the closely-spaced Zapolyarni mines, though discovered that it may be necessary to divide event populations from a single mine into identifiable subpopulations. For this purpose, we perform cluster analysis using matched field statistics calculated on pairs of individual events as a distance metric. In our initial work, calibrations were derived from ensembles of events ranging in number to more than 100. We are considering the performance now of matched field calibrations derived with many fewer events (even, as mentioned, individual events). Since these are high-variance estimates, we are testing the use of cross-channel, multitaper, spectral estimation methods to reduce the variance of calibrations and detection statistics derived from single-event observations. To test the applicability of the technique in a different tectonic region, we have obtained four years of continuous data from 4 Kazakh arrays and are extracting large numbers of event segments. Our initial results using 132 mining explosions recorded by the Makanchi array are similar to those obtained in the European Arctic. Matched field processing clearly separates the explosions from three closely-spaced mines located approximately 400 kilometers from the array, again using waveforms in a band (6-10 Hz) normally considered incoherent for this array. Having reproduced ARCES-type performance with another small aperture array, we have two additional objectives for matched field processing. We will attempt to extend matched field processing to larger apertures: a 200 km aperture (the KNET) and, if data permit, to an aperture comprised of several Kazakh arrays. We also will investigate the potential of developing matched field processing to roughly locate and classify natural seismicity, which is more diffuse than the concentrated sources of mining explosions that we have investigated to date.« less

Lack of broad functional differences in immunity in fully vaccinated vs. unvaccinated children.

PubMed

Sherrid, Ashley M; Ruck, Candice E; Sutherland, Darren; Cai, Bing; Kollmann, Tobias R

2017-04-01

Concerns have been raised that with an increase in the number of vaccines administered early in life, immune development could be altered, leading to either increased or decreased immune reactivity. We investigated the impact of vaccination on immune status, contrasting the immune response to general, nonantigen-specific stimuli in a cohort of entirely unvaccinated vs. fully vaccinated children at 3-5 y of age. Innate immunity was assessed by quantifying bulk and cell-type-specific cytokine production in response to stimulation with pathogen associated microbial patterns. Adaptive immune status was characterized by assessing lymphocyte proliferation and cytokine production in response to generic T cell stimuli. Our investigations failed to reveal a broadly evident alteration of either innate or adaptive immunity in vaccinated children. Equivalently robust innate and adaptive responses to pathogen associated microbial patterns and generic T cell stimulants were observed in both groups. Although our sample size was small, our data suggest that standard childhood vaccinations do not lead to long-lasting gross alterations of the immune system.

Supersampling multiframe blind deconvolution resolution enhancement of adaptive-optics-compensated imagery of LEO satellites

NASA Astrophysics Data System (ADS)

Gerwe, David R.; Lee, David J.; Barchers, Jeffrey D.

2000-10-01

A post-processing methodology for reconstructing undersampled image sequences with randomly varying blur is described which can provide image enhancement beyond the sampling resolution of the sensor. This method is demonstrated on simulated imagery and on adaptive optics compensated imagery taken by the Starfire Optical Range 3.5 meter telescope that has been artificially undersampled. Also shown are the results of multiframe blind deconvolution of some of the highest quality optical imagery of low earth orbit satellites collected with a ground based telescope to date. The algorithm used is a generalization of multiframe blind deconvolution techniques which includes a representation of spatial sampling by the focal plane array elements in the forward stochastic model of the imaging system. This generalization enables the random shifts and shape of the adaptive compensated PSF to be used to partially eliminate the aliasing effects associated with sub- Nyquist sampling of the image by the focal plane array. The method could be used to reduce resolution loss which occurs when imaging in wide FOV modes.

Adaptive enhancement of learning protocol in hippocampal cultured networks grown on multielectrode arrays

PubMed Central

Pimashkin, Alexey; Gladkov, Arseniy; Mukhina, Irina; Kazantsev, Victor

2013-01-01

Learning in neuronal networks can be investigated using dissociated cultures on multielectrode arrays supplied with appropriate closed-loop stimulation. It was shown in previous studies that weakly respondent neurons on the electrodes can be trained to increase their evoked spiking rate within a predefined time window after the stimulus. Such neurons can be associated with weak synaptic connections in nearby culture network. The stimulation leads to the increase in the connectivity and in the response. However, it was not possible to perform the learning protocol for the neurons on electrodes with relatively strong synaptic inputs and responding at higher rates. We proposed an adaptive closed-loop stimulation protocol capable to achieve learning even for the highly respondent electrodes. It means that the culture network can reorganize appropriately its synaptic connectivity to generate a desired response. We introduced an adaptive reinforcement condition accounting for the response variability in control stimulation. It significantly enhanced the learning protocol to a large number of responding electrodes independently on its base response level. We also found that learning effect preserved after 4–6 h after training. PMID:23745105

A Very Large Array Survey of Polar BAL Quasar Candidates

NASA Astrophysics Data System (ADS)

Olson, Kianna Alexandra; Brotherton, Michael S.; DiPompeo, Michael; Maithil, Jaya

2018-06-01

Polar broad absorption line quasars posses flat radio spectra and jets seen at small angles to the line of sight. Using the VLA we observed twelve polar broad absorption line quasar candidates at L (1.5GHz), C (4.5-5.5GHz), and X (8.5-9.5GHz) bands, and found that their cores display flat spectra. Compared to previous observations in the NVSS and First surveys, the peak flux densities all show significant variation σvar > 3, and brightness temperatures TB ≥ 1012K. Based on these findings, our quasars have the properties expected for objects that posses jets seen nearly pole on.

Successor to the RXTE PCA based upon focusing optics

NASA Astrophysics Data System (ADS)

Gorenstein, Paul

2002-01-01

There is broad interest in a next generation timing mission to succeed the PCA of RXTE which will provide more effective area than its 0.6 square meters and much better energy resolution. Currently prospective missions are, like the PCA, based upon large area detectors. Serious consideration should also be given to a focusing system. The focusing system would be a modular array of relatively small diameter imaging telescopes or concentrators with solid state detectors in their focal planes. For areas exceeding a square meter a focusing system could actually be less complex, more reliable, and for one particular optical design perhaps not much more massive. The total detector area would be only a few percent of the telescope aperture, which makes the acquisition of detectors much less challenging. Today it is possible to obtain commercially a sufficient number of detectors with good energy resolution for all the focal planes of the focusing array. They require only modest cooling and that could be accomplished passively in space. Several optical designs are possible. The disadvantages of an optical system are larger mass, more difficultly obtaining broad bandwidth, smaller field of view, and larger volume to accommodate the focal length distance and a larger diameter. On the other hand, the focusing system is more sensitive to fainter sources, is much more efficient below 2 keV, is less sensitive to background and is likely to be less costly overall than an array of solid state area detectors with equally good energy resolution.

Using PVDF for wavenumber-frequency analysis and excitation of guided waves

NASA Astrophysics Data System (ADS)

Ren, Baiyang; Cho, Hwanjeong; Lissenden, Cliff J.

2018-04-01

The role of transducers in nondestructive evaluation using ultrasonic guided waves cannot be overstated. Energy conversion from electrical to mechanical for actuation and then back to electrical for signal processing broadly describes transduction, but there are many other aspects of transducers that determine their effectiveness. Recently we have reported on polyvinylidene difluoride (PVDF) array sensors that enable determination of the wavenumber spectrum, which enables modal content in the received signal to be characterized. Modal content is an important damage indicator because, for example, mode conversion is a frequent consequence of wave interaction with defects. Some of the positive attributes of PVDF sensors are: broad frequency bandwidth, compliance for use on curved surfaces, limited influence on the passing wave, minimal cross-talk between elements, low profile, low mass, and inexpensive. The anisotropy of PVDF films also enables them to receive either Lamb waves or shear horizontal waves by proper alignment of the material principal coordinate axes. Placing a patterned set of electrodes on the PVDF film provides data from an array of elements. A linear array of elements is used to enable a 2D fast Fourier transform to determine the wavenumber spectrum of both Lamb waves and shear horizontal waves in an aluminum plate. Moreover, since PVDF film can sustain high voltage excitation, high power pulsers can be used to improve the signal-to-noise ratio. The capability of PVDF as a transmitter has been demonstrated with high voltage excitation.

Virtual Battlespace Behavior Generation Through Class Imitation

DTIC Science & Technology

2011-03-01

honed to the pinnacle of human capacity. His 1 mind was similarly trained and equipped with an extensive array of leadership and reactionary toolsets...in this crucial moment, Davis had one clear thought resonating within his mind ; that the outcome of this instant would forever change him. In this same...behavior adaption [17]. Their work includes a proof-of-concept for adaptive human-robot interaction scenarios, in particular focusing on autism

Spacer-length DNA intermediates are associated with Cas1 in cells undergoing primed CRISPR adaptation.

PubMed

Musharova, Olga; Klimuk, Evgeny; Datsenko, Kirill A; Metlitskaya, Anastasia; Logacheva, Maria; Semenova, Ekaterina; Severinov, Konstantin; Savitskaya, Ekaterina

2017-04-07

During primed CRISPR adaptation spacers are preferentially selected from DNA recognized by CRISPR interference machinery, which in the case of Type I CRISPR-Cas systems consists of CRISPR RNA (crRNA) bound effector Cascade complex that locates complementary targets, and Cas3 executor nuclease/helicase. A complex of Cas1 and Cas2 proteins is capable of inserting new spacers in the CRISPR array. Here, we show that in Escherichia coli cells undergoing primed adaptation, spacer-sized fragments of foreign DNA are associated with Cas1. Based on sensitivity to digestion with nucleases, the associated DNA is not in a standard double-stranded state. Spacer-sized fragments are cut from one strand of foreign DNA in Cas1- and Cas3-dependent manner. These fragments are generated from much longer S1-nuclease sensitive fragments of foreign DNA that require Cas3 for their production. We propose that in the course of CRISPR interference Cas3 generates fragments of foreign DNA that are recognized by the Cas1-Cas2 adaptation complex, which excises spacer-sized fragments and channels them for insertion into CRISPR array. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Enhancing Teaching using MATLAB Add-Ins for Excel

ERIC Educational Resources Information Center

Hamilton, Paul V.

2004-01-01

In this paper I will illustrate how to extend the capabilities of Microsoft Excel spreadsheets with add-ins created by MATLAB. Excel provides a broad array of fundamental tools but often comes up short when more sophisticated scenarios are involved. To overcome this short-coming of Excel while retaining its ease of use, I will describe how…

Family Abductors: Descriptive Profiles and Preventive Interventions. Juvenile Justice Bulletin.

ERIC Educational Resources Information Center

Johnston, Janet R.; Girdner, Linda K.

Parental abduction encompasses a broad array of illegal behaviors that involves one parent taking, detaining, concealing, or enticing away his or her child from the parent having custodial access. When the abducted parent intends to permanently alter custodial access by hiding the child or removing the child to another locale, the effects on the…

Kentucky Environmental Education Council Goals in Kentucky Elementary Schools: A Descriptive Case Study

ERIC Educational Resources Information Center

Hodge, Connie

2013-01-01

Environmental Education (EE) refers to a broad array of approaches in which an instructor uses the environment as a means to integrate various subjects and real world learning. Research supported the idea that EE instruction had a positive correlation to academic achievement. Under the Kentucky Education Cabinet of the Department of Education, the…

Natural product-based 6-hydroxy-2 3 4 6-tetrahydropyrrolo[1 2-a]pyrimidinium Scaffold as a new antifungal template

USDA-ARS?s Scientific Manuscript database

Synthetic analogues of the marine-derived class of natural products phloeodictines have been prepared and exhibited potent in vitro fungicidal activities against a broad array of fungal pathogens including drug-resistant strains. The 6-hydroxy-2,3,4,6-tetrahydropyrrolo[1,2-a] pyrimidinium structura...

Alternatives to clearcutting of old growth in southeast Alaska.

Treesearch

Sally. Duncan

1999-01-01

This issue of Science Findings examines the results of a study designed to provide a broad array of silvicultural options for land managers. Pacific Northwest Research Station scientist Mike McClellan is leading the study and has found that timber harvesting by using alternatives to clearcutting is viable in the current marketplace and technically feasible across a...

Photogrammetric system and method used in the characterization of a structure

NASA Technical Reports Server (NTRS)

Watson, Kent A. (Inventor); Connell, John W. (Inventor); Pappa, Richard S. (Inventor); Belvin, W. Keith (Inventor); Dorrington, Adrian A. (Inventor); Jones, Thomas W. (Inventor); Danehy, Paul M. (Inventor)

2010-01-01

A photogrammetric system uses an array of spaced-apart targets coupled to a structure. Each target exhibits fluorescence when exposed to a broad beam of illumination. A photogrammetric imaging system located remotely with respect to the structure detects and processes the fluorescence (but not the illumination wavelength) to measure the shape of a structure.

Critical Pathways to School Readiness: Implications for First 5 Ventura County Strategic Planning, Funding and Evaluation

ERIC Educational Resources Information Center

Thompson, Lisa; Tullis, Ericka; Franke, Todd; Halfon, Neal

2005-01-01

The UCLA Center for Healthier Children, Families and Communities (CHCFC) has developed the School Readiness Critical Pathways (SRCPs) as an evidence-based conceptual model that links related outcomes and strategies. This helps to organize an array of broad and diffuse evidence regarding the strategies that produce school readiness outcomes for…

Terrestrial condition assessment for national forests of the USDA Forest Service in the continental US

Treesearch

David Cleland; Keith Reynolds; Robert Vaughan; Barbara Schrader; Harbin Li; Larry Laing

2017-01-01

The terrestrial condition assessment (TCA) evaluates effects of uncharacteristic stressors and disturbance agents on land-type associations (LTAs) to identify restoration opportunities on national forest system (NFS) lands in the United States. A team of agency scientists and managers, representing a broad array of natural resource disciplines, developed a logic...

Contemporary Trends in ADHD Research

ERIC Educational Resources Information Center

Norvilitis, Jill M., Ed.

2012-01-01

With many children and adults affected by Attention Deficit Hyperactivity Disorder, researchers strive to understand the underpinnings of ADHD and associated factors on both a basic and applied level. The goal of this volume is to explore some of the broad array of research in the field of ADHD. The 12 chapters cover a variety of topics as varied…

3 CFR 8573 - Proclamation 8573 of October 1, 2010. National Cybersecurity Awareness Month, 2010

Code of Federal Regulations, 2011 CFR

2011-01-01

... potential risks. The same technology that provides new opportunities for economic growth and the free... technology and communications infrastructure. We must continue to work closely with a broad array of partners... children online. I urge all Americans to visit DHS.gov/Cyber and OnGuardOnline.gov for more information...

A history of plant improvement by the USDA-ARS Forage and Range Research Laboratory for rehabilitation of degraded western U.S. rangelands

USDA-ARS?s Scientific Manuscript database

The semi-arid and arid rangelands and irrigated pastures of the western U.S. provide a broad array of ecosystem services, includig wildlife/livestock feed, a diversity of native plants, pollinators, wildlife, and recreational activities. However, disturbances by wildfire, livestock, wildlife, and h...

Sustaining Productivity of Planted Forests in the Gulf Coast Region

Treesearch

James P. Bamett; Allan E. Tiarks; Mary Anne Sword

2000-01-01

The forests of the Gulf Coastal Region provide the basis for its economic well-being. Because of the semitropical climate, abundant rainfall and availing topography, the nation's richest plant communities thrive. These forests are predominately privately owned. Millions of private landowners are committed to managing their forests for a broad array of values which...

Peptide and protein biomarkers for type 1 diabetes mellitus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Qibin; Metz, Thomas O.

A method for identifying persons with increased risk of developing type 1 diabetes mellitus, or having type I diabetes mellitus, utilizing selected biomarkers described herein either alone or in combination. The present disclosure allows for broad based, reliable, screening of large population bases. Also provided are arrays and kits that can be used to perform such methods.

Peptide and protein biomarkers for type 1 diabetes mellitus

DOEpatents

Zhang, Qibin; Metz, Thomas O.

2014-06-10

A method for identifying persons with increased risk of developing type 1 diabetes mellitus, or having type I diabetes mellitus, utilizing selected biomarkers described herein either alone or in combination. The present disclosure allows for broad based, reliable, screening of large population bases. Also provided are arrays and kits that can be used to perform such methods.

Explorations in Principal Leadership across an Array of School Types.

ERIC Educational Resources Information Center

Portin, Bradley S.

The centrality of school leadership as a necessary element for school success is a well-determined part of the educational leadership research canon. Although school leadership is broad-based and includes many factors, the central role the principal plays is most often seen as a pivot around which much of a school's progress depends. However, it…

Practice Parameter on Child and Adolescent Mental Health Care in Community Systems of Care

ERIC Educational Resources Information Center

Journal of the American Academy of Child and Adolescent Psychiatry, 2007

2007-01-01

This parameter presents overarching principles and practices for child and adolescent mental health care in community systems of care. Community systems of care are defined broadly as comprising the wide array of child-serving agencies, programs, and practitioners (both public and private), in addition to natural community supports such as…

Test Anxiety: Theory, Assessment, and Treatment. The Series in Clinical and Community Psychology.

ERIC Educational Resources Information Center

Spielberger, Charles D., Ed.; Vagg, Peter R., Ed.

It is not surprising that a broad array of treatment programs have been developed to reduce test anxiety, since the consequences can be serious. The contributions in this volume review and evaluate the theory of test anxiety, its measurement, its manifestations, and possible treatments and their outcomes. The following chapters are included: (1)…

Quantum anomalous Hall Majorana platform

NASA Astrophysics Data System (ADS)

Zeng, Yongxin; Lei, Chao; Chaudhary, Gaurav; MacDonald, Allan H.

2018-02-01

We show that quasi-one-dimensional quantum wires can be written onto the surface of magnetic topological insulator (MTI) thin films by gate arrays. When the MTI is in a quantum anomalous Hall state, MTI/superconductor quantum wires have especially broad stability regions for both topological and nontopological states, facilitating creation and manipulation of Majorana particles on the MTI surface.

Understanding Higher Education Institutions' Publicness: Do Public Universities Produce More Public Outcomes than Private Universities?

ERIC Educational Resources Information Center

Lee, Young-Joo

2017-01-01

Higher education institutions produce a broad array of public outcomes. However, little is known about the varying levels of their contribution to the public good and what explains the variation among institutions. This study uses the theory of organisational publicness and examines how these institutions' ownership status and resource publicness…

The importance of quality control in validating concentrations of contaminants of emerging concern in source and treated drinking water samples

EPA Science Inventory

A national scale survey of 251 chemical contaminants in source and finished drinking water was conducted at 25 drinking water treatment plants across the U.S. To address the necessity of using multiple methods in determining a broad array of CECs, we designed a quality assurance/...

A Proposed Methodology for the Conceptualization, Operationalization, and Empirical Validation of the Concept of Information Need

ERIC Educational Resources Information Center

Afzal, Waseem

2017-01-01

Introduction: The purpose of this paper is to propose a methodology to conceptualize, operationalize, and empirically validate the concept of information need. Method: The proposed methodology makes use of both qualitative and quantitative perspectives, and includes a broad array of approaches such as literature reviews, expert opinions, focus…

A comparison of trap type and height for capturing cerambycid beetles (Coleoptera)

Treesearch

Elizabeth E. Graham; Therese M. Poland; Deborah G. McCullough; Jocelyn G. Millar

2012-01-01

Wood-boring beetles in the family Cerambycidae (Coleoptera) play important roles in many forest ecosystems. However, increasing numbers of invasive cerambycid species are transported to new countries by global commerce and threaten forest health in the United States and worldwide. Our goal was to identify effective detection tools for a broad array of cerambycid...

Legislative Aides: A Description of an Undergraduate Internship Program

ERIC Educational Resources Information Center

Orkow, Bonnie Marie

2007-01-01

The intent of a liberal arts education is to expose students to a broad array of ideas and subject matter. Its perceived weakness involves the possible lack of preparedness for the workplace; a liberal arts education is deliberately not vocational. To bridge that divide colleges and universities, in cooperation with industry, non-profits, and the…

Participants' Experiences in Hellinger's Family Constellation Work: A Grounded Theory Study

ERIC Educational Resources Information Center

Georgiadou, Sofia

2012-01-01

As a recently introduced to the U.S. model of intergenerational systemic therapy from Germany, Bert Hellinger's Family Constellation Work (FCW) has very limited research support. Hellinger himself has authored a number of publications referencing hundreds of cases, where he implemented his method to approach a broad array of physical,…

Plasmon-enhanced Electrically Light-emitting from ZnO Nanorod Arrays/p-GaN Heterostructure Devices

PubMed Central

Lu, Junfeng; Shi, Zengliang; Wang, Yueyue; Lin, Yi; Zhu, Qiuxiang; Tian, Zhengshan; Dai, Jun; Wang, Shufeng; Xu, Chunxiang

2016-01-01

Effective and bright light-emitting-diodes (LEDs) have attracted broad interests in fundamental research and industrial application, especially on short wavelength LEDs. In this paper, a well aligned ZnO nanorod arrays grown on the p-GaN substrate to form a heterostructured light-emitting diode and Al nanoparticles (NPs) were decorated to improve the electroluminescence performance. More than 30-folds enhancement of the electroluminescence intensity was obtained compared with the device without Al NPs decoration. The investigation on the stable and transient photoluminescence spectraof the ZnO nanorod arrays before and after Al NPs decoration demonstrated that the metal surface plasmon resonance coupling with excitons of ZnO leads to the enhancement of the internal quantum efficiency (IQE). Our results provide aneffective approach to design novel optoelectronic devices such as light-emitting diodes and plasmonic nanolasers. PMID:27181337

A Numerical Model of Exchange Chromatography Through 3D Lattice Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salloum, Maher; Robinson, David B.

Rapid progress in the development of additive manufacturing technologies is opening new opportunities to fabricate structures that control mass transport in three dimensions across a broad range of length scales. We describe a structure that can be fabricated by newly available commercial 3D printers. It contains an array of regular three-dimensional flow paths that are in intimate contact with a solid phase, and thoroughly shuffle material among the paths. We implement a chemically reacting flow model to study its behavior as an exchange chromatography column, and compare it to an array of one-dimensional flow paths that resemble more traditional honeycombmore » monoliths. A reaction front moves through the columns and then elutes. Here, the front is sharper at all flow rates for the structure with three-dimensional flow paths, and this structure is more robust to channel width defects than the one-dimensional array.« less

Plasmon-enhanced Electrically Light-emitting from ZnO Nanorod Arrays/p-GaN Heterostructure Devices.

PubMed

Lu, Junfeng; Shi, Zengliang; Wang, Yueyue; Lin, Yi; Zhu, Qiuxiang; Tian, Zhengshan; Dai, Jun; Wang, Shufeng; Xu, Chunxiang

2016-05-16

Effective and bright light-emitting-diodes (LEDs) have attracted broad interests in fundamental research and industrial application, especially on short wavelength LEDs. In this paper, a well aligned ZnO nanorod arrays grown on the p-GaN substrate to form a heterostructured light-emitting diode and Al nanoparticles (NPs) were decorated to improve the electroluminescence performance. More than 30-folds enhancement of the electroluminescence intensity was obtained compared with the device without Al NPs decoration. The investigation on the stable and transient photoluminescence spectraof the ZnO nanorod arrays before and after Al NPs decoration demonstrated that the metal surface plasmon resonance coupling with excitons of ZnO leads to the enhancement of the internal quantum efficiency (IQE). Our results provide aneffective approach to design novel optoelectronic devices such as light-emitting diodes and plasmonic nanolasers.

Chemistry and Star Formation: A Love-Hate Relationship

NASA Astrophysics Data System (ADS)

Jiménez-Serra, Izaskun; Zhang, Qizhou; Patel, Nimesh; Lu, Xing; Wang, Ke; Testi, Leonardo; Caselli, Paola; Martin-Pintado, Jesus

2014-06-01

The development of the broad bandwidth receivers at the Submillimeter Array (SMA) a decade ago opened up the possibility to observe tens of molecular lines at high angular resolution simultaneously. The unprecedented wealth of molecular line data provided by the SMA allowed for the first time detailed studies of the chemistry in star-forming regions. These studies have revealed that chemistry is a useful tool to pin down the internal physical structure and the physical processes involved in the process of low-mass and high-mass star formation. In this talk, I will review the most important advances in our understanding of the star-formation process through chemistry thanks to the SMA, and I will present the challenges that will be faced in the next decade in this field of research thanks to the advent of new instrumentation such as the Atacama Large Millimeter/Submillimeter Array and the Square Kilometer Array.

Photochemical methods to assay DNA photocleavage using supercoiled pUC18 DNA and LED or xenon arc lamp excitation.

PubMed

Prussin, Aaron J; Zigler, David F; Jain, Avijita; Brown, Jared R; Winkel, Brenda S J; Brewer, Karen J

2008-04-01

Methods for the study of DNA photocleavage are illustrated using a mixed-metal supramolecular complex [{(bpy)(2)Ru(dpp)}(2)RhCl(2)]Cl(5). The methods use supercoiled pUC18 plasmid as a DNA probe and either filtered light from a xenon arc lamp source or monochromatic light from a newly designed, high-intensity light-emitting diode (LED) array. Detailed methods for performing the photochemical experiments and analysis of the DNA photoproduct are delineated. Detailed methods are also given for building an LED array to be used for DNA photolysis experiments. The Xe arc source has a broad spectral range and high light flux. The LEDs have a high-intensity, nearly monochromatic output. Arrays of LEDs have the advantage of allowing tunable, accurate output to multiple samples for high-throughput photochemistry experiments at relatively low cost.

A Numerical Model of Exchange Chromatography Through 3D Lattice Structures

DOE PAGES

Salloum, Maher; Robinson, David B.

2018-01-30

Rapid progress in the development of additive manufacturing technologies is opening new opportunities to fabricate structures that control mass transport in three dimensions across a broad range of length scales. We describe a structure that can be fabricated by newly available commercial 3D printers. It contains an array of regular three-dimensional flow paths that are in intimate contact with a solid phase, and thoroughly shuffle material among the paths. We implement a chemically reacting flow model to study its behavior as an exchange chromatography column, and compare it to an array of one-dimensional flow paths that resemble more traditional honeycombmore » monoliths. A reaction front moves through the columns and then elutes. Here, the front is sharper at all flow rates for the structure with three-dimensional flow paths, and this structure is more robust to channel width defects than the one-dimensional array.« less

Big data challenges for large radio arrays

NASA Astrophysics Data System (ADS)

Jones, D. L.; Wagstaff, K.; Thompson, D. R.; D'Addario, L.; Navarro, R.; Mattmann, C.; Majid, W.; Lazio, J.; Preston, J.; Rebbapragada, U.

2012-03-01

Future large radio astronomy arrays, particularly the Square Kilometre Array (SKA), will be able to generate data at rates far higher than can be analyzed or stored affordably with current practices. This is, by definition, a "big data" problem, and requires an end-to-end solution if future radio arrays are to reach their full scientific potential. Similar data processing, transport, storage, and management challenges face next-generation facilities in many other fields. The Jet Propulsion Laboratory is developing technologies to address big data issues, with an emphasis in three areas: 1) Lower-power digital processing architectures to make highvolume data generation operationally affordable, 2) Date-adaptive machine learning algorithms for real-time analysis (or "data triage") of large data volumes, and 3) Scalable data archive systems that allow efficient data mining and remote user code to run locally where the data are stored.

Advanced propulsion concepts study: Comparative study of solar electric propulsion and laser electric propulsion

NASA Technical Reports Server (NTRS)

Forward, R. L.

1975-01-01

Solar electric propulsion (SEP) and laser electric propulsion (LEP) was compared. The LEP system configuration consists of an 80 kW visible laser source on earth, transmitting via an 8 m diameter adaptively controlled phased array through the atmosphere to a 4 m diameter synchronous relay mirror that tracks the LEP spacecraft. The only significant change in the SEP spacecraft for an LEP mission is the replacement of the two 3.7 m by 33.5 m solar cell arrays with a single 8 m diameter laser photovoltaic array. The solar cell array weight is decreased from 320 kg to 120 kg for an increase in payload of 200 kg and a decrease in specific mass of the power system from 20.5 kg/kW to 7.8 kg/kW.

Simple and fast method for fabrication of endoscopic implantable sensor arrays.

PubMed

Tahirbegi, I Bogachan; Alvira, Margarita; Mir, Mònica; Samitier, Josep

2014-06-26

Here we have developed a simple method for the fabrication of disposable implantable all-solid-state ion-selective electrodes (ISE) in an array format without using complex fabrication equipment or clean room facilities. The electrodes were designed in a needle shape instead of planar electrodes for a full contact with the tissue. The needle-shape platform comprises 12 metallic pins which were functionalized with conductive inks and ISE membranes. The modified microelectrodes were characterized with cyclic voltammetry, scanning electron microscope (SEM), and optical interferometry. The surface area and roughness factor of each microelectrode were determined and reproducible values were obtained for all the microelectrodes on the array. In this work, the microelectrodes were modified with membranes for the detection of pH and nitrate ions to prove the reliability of the fabricated sensor array platform adapted to an endoscope.

Passive bottom reflection-loss estimation using ship noise and a vertical line array.

PubMed

Muzi, Lanfranco; Siderius, Martin; Verlinden, Christopher M

2017-06-01

An existing technique for passive bottom-loss estimation from natural marine surface noise (generated by waves and wind) is adapted to use noise generated by ships. The original approach-based on beamforming of the noise field recorded by a vertical line array of hydrophones-is retained; however, additional processing is needed in order for the field generated by a passing ship to show features that are similar to those of the natural surface-noise field. A necessary requisite is that the ship position, relative to the array, varies over as wide a range of steering angles as possible, ideally passing directly over the array to ensure coverage of the steepest angles. The methodology is illustrated through simulation and applied to data from a field experiment conducted offshore of San Diego, CA in 2009.

Successes and challenges from formation to implementation of eleven broad-extent conservation programs

USGS Publications Warehouse

Beever, Erik A.; Bradford, John B.; Germino, Matthew J.; Mattsson, Brady J.; Post van der Burg, Max; Brunson, Mark

2014-01-01

Integration of conservation partnerships across geographic, biological, and administrative boundaries is increasingly relevant because drivers of change, such as climate shifts, transcend these boundaries. We explored successes and challenges of established conservation programs that span multiple watersheds and consider both social and ecological concerns. We asked representatives from a diverse set of 11 broadextent conservation partnerships in 29 countries 17 questions that pertained to launching and maintaining partnerships for broad-extent conservation, specifying ultimate management objectives, and implementation and learning. Partnerships invested more funds in implementing conservation actions than any other aspect of conservation, and a program’s context (geographic extent, United States vs. other countries, developed vs. developing nation) appeared to substantially affect program approach. Despite early successes of these organizations and benefits of broad-extent conservation, specific challenges related to uncertainties in scaling up information and to coordination in the face of diverse partner governance structures, conflicting objectives, and vast uncertainties regarding future system dynamics hindered long-term success, as demonstrated by the focal organizations. Engaging stakeholders, developing conservation measures, and implementing adaptive management were dominant challenges. To inform future research on broad-extent conservation, we considered several challenges when we developed detailed questions, such as what qualities of broad-extent partnerships ensure they complement, integrate, and strengthen, rather than replace, local conservation efforts and which adaptive management processes yield actionable conservation strategies that account explicitly for dynamics and uncertainties regarding multiscale governance, environmental conditions, and knowledge of the system?

An experimental SMI adaptive antenna array for weak interfering signals

NASA Technical Reports Server (NTRS)

Dilsavor, R. L.; Gupta, I. J.

1989-01-01

A modified sample matrix inversion (SMI) algorithm designed to increase the suppression of weak interference is implemented on an existing experimental array system. The algorithm itself is fully described as are a number of issues concerning its implementation and evaluation, such as sample scaling, snapshot formation, weight normalization, power calculation, and system calibration. Several experiments show that the steady state performance (i.e., many snapshots are used to calculate the array weights) of the experimental system compares favorably with its theoretical performance. It is demonstrated that standard SMI does not yield adequate suppression of weak interference. Modified SMI is then used to experimentally increase this suppression by as much as 13dB.

Past and future detector arrays for complete event reconstruction in heavy-ion reactions

NASA Astrophysics Data System (ADS)

Cardella, G.; Acosta, L.; Auditore, L.; Boiano, C.; Castoldi, A.; D'Andrea, M.; De Filippo, E.; Dell'Aquila, D.; De Luca, S.; Fichera, F.; Giudice, N.; Gnoffo, B.; Grimaldi, A.; Guazzoni, C.; Lanzalone, G.; Librizzi, F.; Lombardo, I.; Maiolino, C.; Maffesanti, S.; Martorana, N. S.; Norella, S.; Pagano, A.; Pagano, E. V.; Papa, M.; Parsani, T.; Passaro, G.; Pirrone, S.; Politi, G.; Previdi, F.; Quattrocchi, L.; Rizzo, F.; Russotto, P.; Saccà, G.; Salemi, G.; Sciliberto, D.; Trifirò, A.; Trimarchi, M.; Vigilante, M.

2017-11-01

Complex and more and more complete detector arrays have been developed in the last two decades, or are in advanced design stage, in different laboratories. Such arrays are necessary to fully characterize nuclear reactions induced by stable and exotic beams. The need for contemporary detection of charged particles, and/or γ -rays, and/or neutrons, has been stressed in many fields of nuclear structure and reaction dynamics, with particular attention to the improvement of both high angular and energy resolution. Some examples of detection systems adapted to various energy ranges is discussed. Emphasis is given to the possible update of relatively old 4π detectors with new electronics and new detection methods.

High speed, very large (8 megabyte) first in/first out buffer memory (FIFO)

DOEpatents

Baumbaugh, Alan E.; Knickerbocker, Kelly L.

1989-01-01

A fast FIFO (First In First Out) memory buffer capable of storing data at rates of 100 megabytes per second. The invention includes a data packer which concatenates small bit data words into large bit data words, a memory array having individual data storage addresses adapted to store the large bit data words, a data unpacker into which large bit data words from the array can be read and reconstructed into small bit data words, and a controller to control and keep track of the individual data storage addresses in the memory array into which data from the packer is being written and data to the unpacker is being read.

Development of a RadFET Linear Array for Intracavitary in vivo Dosimetry During External Beam Radiotherapy and Brachytherapy

NASA Astrophysics Data System (ADS)

Price, R. A.; Benson, C.; Joyce, M. J.; Rodgers, K.

2004-08-01

We present the details of a new linear array dosimeter consisting of a chain of semiconductors mounted on an ultra-thin (50 /spl mu/m thick) flexible substrate and housed in an intracavitary catheter. The semiconductors, manufactured by NMRC Cork, have not been packaging and incorporate a passivation layer that allows them to be mounted on the substrate using flip-chip-bonding. This paper reports, for the first time, the construction of a multiple (ten) detector array suited to in vivo dosimetry in the rectum, esophagus and vagina during external beam radiotherapy, as well as being adaptable to in vivo dosimetry during brachytherapy and diagnostic radiology.

Uniform rotating field network structure to efficiently package a magnetic bubble domain memory

NASA Technical Reports Server (NTRS)

Murray, Glen W. (Inventor); Chen, Thomas T. (Inventor); Wolfshagen, Ronald G. (Inventor); Ypma, John E. (Inventor)

1978-01-01

A unique and compact open coil rotating magnetic field network structure to efficiently package an array of bubble domain devices is disclosed. The field network has a configuration which effectively enables selected bubble domain devices from the array to be driven in a vertical magnetic field and in an independent and uniform horizontal rotating magnetic field. The field network is suitably adapted to minimize undesirable inductance effects, improve capabilities of heat dissipation, and facilitate repair or replacement of a bubble device.

Solar Photovoltaic Array With Mini-Dome Fresnel Lenses

NASA Technical Reports Server (NTRS)

Piszczor, Michael F., Jr.; O'Neill, Mark J.

1994-01-01

Mini-dome Fresnel lenses concentrate sunlight onto individual photovoltaic cells. Facets of Fresnel lens designed to refract incident light at angle of minimum deviation to minimize reflective losses. Prismatic cover on surface of each cell reduces losses by redirecting incident light away from metal contacts toward bulk of semiconductor, where it is usefully absorbed. Simple design of mini-dome concentrator array easily adaptable to automated manufacturing techniques currently used by semiconductor industry. Attractive option for variety of future space missions.

Characterization of Aluminum Magnesium Alloy Reverse Sensitized via Heat Treatment

DTIC Science & Technology

2016-09-01

been on ships that had seen an unknown cycle of painting - stripping -repainting, so some variation was expected. 16 The exact age and range of...Figure 44. Effect of Temperature on Al-Mg Alloys. Adapted from [9]. d. Other heat treatment techniques – high power diode laser (HPDL) arrays Because...25] B. Baker et. al, "Use of High-Power diode Laser Arrays for Pre- and Post- Weld Heating During Friction Stir Welding of Steels," in Friction