ERIC Educational Resources Information Center
Scott, Paul
2009-01-01
These days, multiplying two numbers together is a breeze. One just enters the two numbers into one's calculator, press a button, and there is the answer! It never used to be this easy. Generations of students struggled with tables of logarithms, and thought it was a miracle when the slide rule first appeared. In this article, the author discusses…
Adding and Subtracting Vectors: The Problem with the Arrow Representation
ERIC Educational Resources Information Center
Heckler, Andrew F.; Scaife, Thomas M.
2015-01-01
A small number of studies have investigated student understanding of vector addition and subtraction in generic or introductory physics contexts, but in almost all cases the questions posed were in the vector arrow representation. In a series of experiments involving over 1000 students and several semesters, we investigated student understanding…
Adding and subtracting vectors: The problem with the arrow representation
NASA Astrophysics Data System (ADS)
Heckler, Andrew F.; Scaife, Thomas M.
2015-06-01
A small number of studies have investigated student understanding of vector addition and subtraction in generic or introductory physics contexts, but in almost all cases the questions posed were in the vector arrow representation. In a series of experiments involving over 1000 students and several semesters, we investigated student understanding of vector addition and subtraction in both the arrow and algebraic notation (using i ^, j ^, k ^) in generic mathematical and physics contexts. First, we replicated a number of previous findings of student difficulties in the arrow format and discovered several additional difficulties, including the finding that different relative arrow orientations can prompt different solution paths and different kinds of mistakes, which suggests that students need to practice with a variety of relative orientations. Most importantly, we found that average performance in the i j k format was typically excellent and often much better than performance in the arrow format in either the generic or physics contexts. Further, while we find that the arrow format tends to prompt students to a more physically intuitive solution path, we also find that, when prompted, student solutions in the i j k format also display significant physical insights into the problem. We also find a hierarchy in correct answering between the two formats, with correct answering in the i j k format being more fundamental than for the arrow format. Overall, the results suggest that many student difficulties with these simple vector problems lie with the arrow representation itself. For instruction, these results imply that introducing the i j k notation (or some equivalent) with the arrow notation concurrently may be a very useful way to improve student performance as well as help students to learn physics concepts involving vector addition and subtraction.
Quality Index for Stereoscopic Images by Separately Evaluating Adding and Subtracting
Yang, Jiachen; Lin, Yancong; Gao, Zhiqun; Lv, Zhihan; Wei, Wei; Song, Houbing
2015-01-01
The human visual system (HVS) plays an important role in stereo image quality perception. Therefore, it has aroused many people’s interest in how to take advantage of the knowledge of the visual perception in image quality assessment models. This paper proposes a full-reference metric for quality assessment of stereoscopic images based on the binocular difference channel and binocular summation channel. For a stereo pair, the binocular summation map and binocular difference map are computed first by adding and subtracting the left image and right image. Then the binocular summation is decoupled into two parts, namely additive impairments and detail losses. The quality of binocular summation is obtained as the adaptive combination of the quality of detail losses and additive impairments. The quality of binocular summation is computed by using the Contrast Sensitivity Function (CSF) and weighted multi-scale (MS-SSIM). Finally, the quality of binocular summation and binocular difference is integrated into an overall quality index. The experimental results indicate that compared with existing metrics, the proposed metric is highly consistent with the subjective quality assessment and is a robust measure. The result have also indirectly proved hypothesis of the existence of binocular summation and binocular difference channels. PMID:26717412
Quality Index for Stereoscopic Images by Separately Evaluating Adding and Subtracting.
Yang, Jiachen; Lin, Yancong; Gao, Zhiqun; Lv, Zhihan; Wei, Wei; Song, Houbing
2015-01-01
The human visual system (HVS) plays an important role in stereo image quality perception. Therefore, it has aroused many people's interest in how to take advantage of the knowledge of the visual perception in image quality assessment models. This paper proposes a full-reference metric for quality assessment of stereoscopic images based on the binocular difference channel and binocular summation channel. For a stereo pair, the binocular summation map and binocular difference map are computed first by adding and subtracting the left image and right image. Then the binocular summation is decoupled into two parts, namely additive impairments and detail losses. The quality of binocular summation is obtained as the adaptive combination of the quality of detail losses and additive impairments. The quality of binocular summation is computed by using the Contrast Sensitivity Function (CSF) and weighted multi-scale (MS-SSIM). Finally, the quality of binocular summation and binocular difference is integrated into an overall quality index. The experimental results indicate that compared with existing metrics, the proposed metric is highly consistent with the subjective quality assessment and is a robust measure. The result have also indirectly proved hypothesis of the existence of binocular summation and binocular difference channels. PMID:26717412
Generation of photon-added coherent states via photon-subtracted generalised coherent states
NASA Astrophysics Data System (ADS)
Mojaveri, Bashir; Dehghani, Alireza
2014-10-01
Based on previous work [A. Dehghani, B. Mojaveri, J. Phys. A 45, 095304 (2012)], we introduce photon-subtracted generalised coherent states (PSGCSs) |z,m⟩r: = am|z⟩r, where m is a nonnegative integer and |z⟩r denote the generalised coherent states (GCSs). We have shown that the states |z,m⟩r are eigenstates of a non-Hermitian operator f(n̂,m)â, where f(n̂,m) is a nonlinear function of the number operator N̂ . Also, the states | z, - m ⟩ r can be considered as another set of eigenstates for negative values of m. They span the truncated Fock space without the first m lowest-lying basis states: | 0 ⟩ , | 1 ⟩ , | 2 ⟩ ,...,| m - 1 ⟩ which are reminiscent of the so-called photon-added coherent states. The resolution of the identity property, which is the most important property of coherent states, is realised for |z,m⟩r as well as for |z, - m⟩r. Some nonclassical features such as sub-Poissonian statistics and quadrature squeezing of the states |z, ± m⟩r are compared. We show that the annihilation operator diminishes the mean number of photons of the initial state |z⟩r. Finally we show that |z,m⟩r can be produced through a simple theoretical scheme.
ERIC Educational Resources Information Center
Henderson, Jimmy Dale
2011-01-01
This study examined the perceptions of principals, teachers, and support staff at 3 PREPS-identified value added and three PREPS-identified value subtracted elementary schools in Mississippi to determine if there were "effective schools" practices in the areas of instructional and organizational systems that were unique to either group. The…
Pierce, Paul E.
1986-01-01
A hardware processor is disclosed which in the described embodiment is a memory mapped multiplier processor that can operate in parallel with a 16 bit microcomputer. The multiplier processor decodes the address bus to receive specific instructions so that in one access it can write and automatically perform single or double precision multiplication involving a number written to it with or without addition or subtraction with a previously stored number. It can also, on a single read command automatically round and scale a previously stored number. The multiplier processor includes two concatenated 16 bit multiplier registers, two 16 bit concatenated 16 bit multipliers, and four 16 bit product registers connected to an internal 16 bit data bus. A high level address decoder determines when the multiplier processor is being addressed and first and second low level address decoders generate control signals. In addition, certain low order address lines are used to carry uncoded control signals. First and second control circuits coupled to the decoders generate further control signals and generate a plurality of clocking pulse trains in response to the decoded and address control signals.
Pierce, P.E.
A hardware processor is disclosed which in the described embodiment is a memory mapped multiplier processor that can operate in parallel with a 16 bit microcomputer. The multiplier processor decodes the address bus to receive specific instructions so that in one access it can write and automatically perform single or double precision multiplication involving a number written to it with or without addition or subtraction with a previously stored number. It can also, on a single read command automatically round and scale a previously stored number. The multiplier processor includes two concatenated 16 bit multiplier registers, two 16 bit concatenated 16 bit multipliers, and four 16 bit product registers connected to an internal 16 bit data bus. A high level address decoder determines when the multiplier processor is being addressed and first and second low level address decoders generate control signals. In addition, certain low order address lines are used to carry uncoded control signals. First and second control circuits coupled to the decoders generate further control signals and generate a plurality of clocking pulse trains in response to the decoded and address control signals.
Chase, R.L.
1963-05-01
An electronic fast multiplier circuit utilizing a transistor controlled voltage divider network is presented. The multiplier includes a stepped potentiometer in which solid state or transistor switches are substituted for mechanical wipers in order to obtain electronic switching that is extremely fast as compared to the usual servo-driven mechanical wipers. While this multiplier circuit operates as an approximation and in steps to obtain a voltage that is the product of two input voltages, any desired degree of accuracy can be obtained with the proper number of increments and adjustment of parameters. (AEC)
Numerical integration of subtraction terms
NASA Astrophysics Data System (ADS)
Seth, Satyajit; Weinzierl, Stefan
2016-06-01
Numerical approaches to higher-order calculations often employ subtraction terms, both for the real emission and the virtual corrections. These subtraction terms have to be added back. In this paper we show that at NLO the real subtraction terms, the virtual subtraction terms, the integral representations of the field renormalization constants and—in the case of initial-state partons—the integral representation for the collinear counterterm can be grouped together to give finite integrals, which can be evaluated numerically. This is useful for an extension towards next-to-next-to-leading order.
Thomas, R.E.
1959-01-20
An electronic circuit is presented for automatically computing the product of two selected variables by multiplying the voltage pulses proportional to the variables. The multiplier circuit has a plurality of parallel resistors of predetermined values connected through separate gate circults between a first input and the output terminal. One voltage pulse is applied to thc flrst input while the second voltage pulse is applied to control circuitry for the respective gate circuits. Thc magnitude of the second voltage pulse selects the resistors upon which the first voltage pulse is imprcssed, whereby the resultant output voltage is proportional to the product of the input voltage pulses
Collier, D.M.; Meeks, L.A.; Palmer, J.P.
1961-01-31
S>An electronic multiplier is described for use in analog computers. Two electrical input signals are received; one controls the slope of a saw-tooth voltage wave while the other controls the time duration of the wave. A condenser and diode clamps are provided to sustain the crest voltage reached by the wave, and for storing that voltage to provide an output signal which is a steady d-c voltage.
Jodoin, Pierre-Marc; Saligrama, Venkatesh; Konrad, Janusz
2012-09-01
Background subtraction has been a driving engine for many computer vision and video analytics tasks. Although its many variants exist, they all share the underlying assumption that photometric scene properties are either static or exhibit temporal stationarity. While this works in many applications, the model fails when one is interested in discovering changes in scene dynamics instead of changes in scene's photometric properties; the detection of unusual pedestrian or motor traffic patterns are but two examples. We propose a new model and computational framework that assume the dynamics of a scene, not its photometry, to be stationary, i.e., a dynamic background serves as the reference for the dynamics of an observed scene. Central to our approach is the concept of an event, which we define as short-term scene dynamics captured over a time window at a specific spatial location in the camera field of view. Unlike in our earlier work, we compute events by time-aggregating vector object descriptors that can combine multiple features, such as object size, direction of movement, speed, etc. We characterize events probabilistically, but use low-memory, low-complexity surrogates in a practical implementation. Using these surrogates amounts to behavior subtraction, a new algorithm for effective and efficient temporal anomaly detection and localization. Behavior subtraction is resilient to spurious background motion, such as due to camera jitter, and is content-blind, i.e., it works equally well on humans, cars, animals, and other objects in both uncluttered and highly cluttered scenes. Clearly, treating video as a collection of events rather than colored pixels opens new possibilities for video analytics.
Thomas, R.E.
1959-08-25
An electronic multiplier circuit is described in which an output voltage having an amplitude proportional to the product or quotient of the input signals is accomplished in a novel manner which facilitates simplicity of circuit construction and a high degree of accuracy in accomplishing the multiplying and dividing function. The circuit broadly comprises a multiplier tube in which the plate current is proportional to the voltage applied to a first control grid multiplied by the difference between voltage applied to a second control grid and the voltage applied to the first control grid. Means are provided to apply a first signal to be multiplied to the first control grid together with means for applying the sum of the first signal to be multiplied and a second signal to be multiplied to the second control grid whereby the plate current of the multiplier tube is proportional to the product of the first and second signals to be multiplied.
Four-quadrant CCD analog multiplier
NASA Technical Reports Server (NTRS)
Brooks, C. W.; Lampe, D. R.
1981-01-01
Sequential processing technique improves accuracy when CCD-array signals are multiplied by weighting function to remove offsets. System uses two schemes to cancel undesired output contributions arising from prerequisite biases. First is spontaneous cancellation by multiple "nominally identical" devices; second is sequential cancellation where same devices are used repeatedly to form multiple products. Single device then successively subtracts products, eliminating effects of MOS-array threshold nonuniformities.
SECONDARY ELECTRON MULTIPLIERS
Morton, G.A.; Green, M.W.
1959-01-01
A secondary emission multiplier having exceptionally high output signal current is described. In previous multiplier tubes the output signal current was limited by the space charge surrounding the electrodes. The present multiplier tubes provides a source of ions within the tube adjacent the anode to neutralize the space charge effect, and the dynode voltage is switched on intermittently for periods of time so brief that the ions do not move towards the cathode.
Pressure multiplying dispenser
DeFord, Henry S.; Moss, Owen R.
1986-01-01
A pressure multiplying dispenser for delivering fluid, preferably as a spray to the atmosphere, from a source of fluid, preferably a spray bottle, is described. The dispenser includes in combination a hollow cylindrical member, a nozzle delivery tube within the cylindrical member and a hollow actuator piston slideable within the cylindrical member which acts to multiply the pressure of a squeeze applied to the spray bottle.
NASA Astrophysics Data System (ADS)
Frixione, Stefano; Grazzini, Massimiliano
2005-06-01
We propose a framework for the implementation of a subtraction formalism at NNLO in QCD, based on an observable- and process-independent cancellation of infrared singularities. As a first simple application, we present the calculation of the contribution to the e+e- dijet cross section proportional to CFTR.
The Multiply Handicapped Child.
ERIC Educational Resources Information Center
Wolf, James M., Ed.; Anderson, Robert M., Ed.
Articles presented in the area of the medical and educational challenge of the multiply handicapped child are an overview of the problem, the increasing challenge, congenital malformations, children whose mothers had rubella, prematurity and deafness, the epidemiology of reproductive casualty, and new education for old problems. Discussions of…
ERIC Educational Resources Information Center
Nelson, Jane Bray
2012-01-01
As a new physics teacher, I was explaining how to find the weight of an object sitting on a table near the surface of the Earth. It bothered me when a student asked, "The object is not accelerating so why do you multiply the mass of the object by the acceleration due to gravity?" I answered something like, "That's true, but if the table were not…
Terahertz Schottky Multiplier Sources
NASA Technical Reports Server (NTRS)
Schlecht, Erich T.
2007-01-01
This viewgraph presentation reviews the multiplier source technologies and the status/Performance of THz multiplier sources. An example of a THz application is imaging radar. The presentation reviews areas of requirements for THz sources: (1) Figures of merit, (i.e., Frequency Terahertz for high resolution Bandwidth of at least 15 GHz for high range resolution Efficiency (i.e., minimize power supply requirements) (2) Output power: (i.e., Milliwatts below 800 GHz, 10s of microwatts above 1 THz, 1-2 microwatts near 2 THz (3) Mechanical--stability, compact, low mass (4) Environmental -- radiation, vibration, thermal. Several sources for 0.3 - 2 THz are reviewed: FIR lasers, quantum cascade lasers (QCL), backward-wave oscillator (BWO), and Multiplier sources. The current state of the art (SoA) is shown as Substrateless Technology. It also shows where the SoA is for devices beyond 1 THz. The presentation concludes by reviewing the options for future development, and 2 technology roadmaps
Monolithic THz Frequency Multipliers
NASA Technical Reports Server (NTRS)
Erickson, N. R.; Narayanan, G.; Grosslein, R. M.; Martin, S.; Mehdi, I.; Smith, P.; Coulomb, M.; DeMartinez, G.
2001-01-01
Frequency multipliers are required as local oscillator sources for frequencies up to 2.7 THz for FIRST and airborne applications. Multipliers at these frequencies have not previously been demonstrated, and the object of this work was to show whether such circuits are really practical. A practical circuit is one which not only performs as well as is required, but also can be replicated in a time that is feasible. As the frequency of circuits is increased, the difficulties in fabrication and assembly increase rapidly. Building all of the circuit on GaAs as a monolithic circuit is highly desirable to minimize the complexity of assembly, but at the highest frequencies, even a complete monolithic circuit is extremely small, and presents serious handling difficulty. This is compounded by the requirement for a very thin substrate. Assembly can become very difficult because of handling problems and critical placement. It is very desirable to make the chip big enough to that it can be seen without magnification, and strong enough that it may be picked up with tweezers. Machined blocks to house the chips present an additional challenge. Blocks with complex features are very expensive, and these also imply very critical assembly of the parts. It would be much better if the features in the block were as simple as possible and non-critical to the function of the chip. In particular, grounding and other electrical interfaces should be done in a manner that is highly reproducible.
Hardware Implementation of a Bilateral Subtraction Filter
NASA Technical Reports Server (NTRS)
Huertas, Andres; Watson, Robert; Villalpando, Carlos; Goldberg, Steven
2009-01-01
its position in the window as well as the pixel value for the central pixel of the window. The absolute difference between these two pixel values is calculated and used as an address in a lookup table. Each processing element has a lookup table, unique for its position in the window, containing the weight coefficients for the Gaussian function for that position. The pixel value is multiplied by the weight, and the outputs of the processing element are the weight and pixel-value weight product. The products and weights are fed to the adder tree. The sum of the products and the sum of the weights are fed to the divider, which computes the sum of products the sum of weights. The output of the divider is denoted the bilateral smoothed image. The smoothing function is a simple weighted average computed over a 3 3 subwindow centered in the 9 9 window. After smoothing, the image is delayed by an additional amount of time needed to match the processing time for computing the bilateral smoothed image. The bilateral smoothed image is then subtracted from the 3 3 smoothed image to produce the final output. The prototype filter as implemented in a commercially available FPGA processes one pixel per clock cycle. Operation at a clock speed of 66 MHz has been demonstrated, and results of a static timing analysis have been interpreted as suggesting that the clock speed could be increased to as much as 100 MHz.
CCD Base Line Subtraction Algorithms
Kotov, I.V.; OConnor, P.; Kotov, A.; Frank, J.; Perevoztchikov, V.; Takacs, P.
2010-06-28
High statistics astronomical surveys require photometric accuracy on a few percent level. The accuracy of sensor calibration procedures should match this goal. The first step in calibration procedures is the base line subtraction. The accuracy and robustness of different base line subtraction techniques used for Charge Coupled Device (CCD) sensors are discussed.
UWB delay and multiply receiver
Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.
2013-09-10
An ultra-wideband (UWB) delay and multiply receiver is formed of a receive antenna; a variable gain attenuator connected to the receive antenna; a signal splitter connected to the variable gain attenuator; a multiplier having one input connected to an undelayed signal from the signal splitter and another input connected to a delayed signal from the signal splitter, the delay between the splitter signals being equal to the spacing between pulses from a transmitter whose pulses are being received by the receive antenna; a peak detection circuit connected to the output of the multiplier and connected to the variable gain attenuator to control the variable gain attenuator to maintain a constant amplitude output from the multiplier; and a digital output circuit connected to the output of the multiplier.
Enhancing quantum entanglement by photon addition and subtraction
NASA Astrophysics Data System (ADS)
Navarrete-Benlloch, Carlos; García-Patrón, Raúl; Shapiro, Jeffrey H.; Cerf, Nicolas J.
2012-07-01
The non-Gaussian operations effected by adding or subtracting a photon on entangled optical beams emerging from a parametric down-conversion process have been suggested to enhance entanglement. Heralded photon addition or subtraction is, as a matter of fact, at the heart of continuous-variable entanglement distillation. The use of such processes has recently been experimentally demonstrated in the context of the generation of optical coherent-state superpositions or the verification of canonical commutation relations. Here, we carry out a systematic study of the effect of local photon additions and subtractions on a two-mode squeezed vacuum state, showing that the entanglement generally increases with the number of such operations. This is analytically proven when additions or subtractions are restricted to one mode only, while we observe that the highest entanglement is achieved when these operations are equally shared between the two modes. We also note that adding photons typically provides a stronger entanglement enhancement than subtracting photons, while photon subtraction performs better in terms of energy efficiency. Furthermore, we analyze the interplay between entanglement and non-Gaussianity, showing that it is more subtle than previously expected.
NULL Convention Floating Point Multiplier
Ramachandran, Seshasayanan
2015-01-01
Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069
Effective switching frequency multiplier inverter
Su, Gui-Jia; Peng, Fang Z.
2007-08-07
A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.
ERIC Educational Resources Information Center
Baroody, Arthur J.
2016-01-01
Six widely used US Grade 1 curricula do not adequately address the following three developmental prerequisites identified by a proposed learning trajectory for the meaningful learning of the subtraction-as-addition strategy (e.g., for 13-8 think "what + 8 = 13?"): (a) reverse operations (adding 8 is undone by subtracting 8); (b) common…
Color Addition and Subtraction Apps
NASA Astrophysics Data System (ADS)
Ruiz, Frances; Ruiz, Michael J.
2015-10-01
Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step in understanding mathematical representations of RGB color. Finally, color addition and subtraction are presented for the X11 colors from web design to illustrate yet another real-life application of color mixing.
Multipliers in weighted Sobolev spaces
NASA Astrophysics Data System (ADS)
Kusainova, L. K.
2005-08-01
Let X_1 and X_2 be a pair of Banach spaces of functions in \\Omega\\subset{\\mathbb R}^n. A multiplier from X_1 into X_2 is a function \\gamma on \\Omega such that \\gamma X_1=\\{\\gamma f,\\ f\\in X_1\\}\\subset X_2. By the norm \\Vert\\gamma\\Vert=\\Vert\\gamma\\Vert _{M(X_1\\to X_2)} one means the norm of the operator T(u)=\\gamma u, u\\in X_1. Conditions ensuring that a function \\gamma belongs to the multiplier classes M(W_1\\to W_2) and M(W\\to L) are found, where W and L are Sobolev and Lebesgue weighted spaces, respectively. Estimates of the norms of multipliers free from capacity characteristics are found. Special local maximal operators are introduced and significantly used.
Color Addition and Subtraction Apps
ERIC Educational Resources Information Center
Ruiz, Frances; Ruiz, Michael J.
2015-01-01
Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…
Bandpass x-ray diode and x-ray multiplier detector
Wang, C.L.
1982-09-27
An absorption-edge of an x-ray absorption filter and a quantum jump of a photocathode determine the bandpass characteristics of an x-ray diode detector. An anode, which collects the photoelectrons emitted by the photocathode, has enhanced amplification provided by photoelectron-multiplying means which include dynodes or a microchannel-plate electron-multiplier. Suppression of undesired high frequency response for a bandpass x-ray diode is provided by subtracting a signal representative of energies above the passband from a signal representative of the overall response of the bandpass diode.
Multimode theory of single-photon subtraction
NASA Astrophysics Data System (ADS)
Averchenko, V.; Jacquard, C.; Thiel, V.; Fabre, C.; Treps, N.
2016-08-01
We develop a general theory to describe the manipulation of a multimode quantum state of light via the subtraction of a single photon. The theory is applicable for various types of subtraction schemes independent of the physical nature of the light modes, their number or the embedded quantum states. We show that different subtraction schemes can be described in a unified approach through the characterization of their intrinsic subtraction modes. The conditional state of the multimode quantum light after the photon subtraction is defined by the number of subtraction modes and their matching with the light modes. We propose the manipulation of light states by controlling the subtraction modes. Performing a photon subtraction on a multimode quantum resource is promising for the implementation of a number of quantum information protocols in all-optical, multiplexed and scalable way.
Sky subtraction with fiber spectrographs
NASA Astrophysics Data System (ADS)
Lissandrini, C.; Cristiani, S.; La Franca, F.
1994-11-01
The sky-subtraction performance of multifiber spectrographs is discussed, analyzing in detail the case of the OPTOPUS system at the 3.6-m European Space Observatory (ESO) telescope at La Silla. A standard technique, based on flat fields obtained with a uniformly illuminated screen on the dome, provides poor results. A new method has been developed, using the (O I) emission line at 5577 A as a calibrator of the fiber transmittance, taking into account the diffuse light and the influence of each fiber on the adjacent ones, and correcting for the effects of the image distortions on the sky sampling. In this way the accuracy of the sky subtraction improves from 2%-8% to 1.3%-1.6%.
Embossed radiography utilizing energy subtraction.
Osawa, Akihiro; Watanabe, Manabu; Sato, Eiichi; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Nagao, Jiro; Abderyim, Purkhet; Aizawa, Katsuo; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Ehara, Shigeru; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun
2009-01-01
Currently, it is difficult to carry out refraction-contrast radiography by using a conventional X-ray generator. Thus, we developed an embossed radiography system utilizing dual-energy subtraction for decreasing the absorption contrast in unnecessary regions, and the contrast resolution of a target region was increased by use of image-shifting subtraction and a linear-contrast system in a flat panel detector (FPD). The X-ray generator had a 100-microm-focus tube. Energy subtraction was performed at tube voltages of 45 and 65 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. A 1.0-mm-thick aluminum filter was used for absorbing low-photon-energy bremsstrahlung X-rays. Embossed radiography was achieved with cohesion imaging by use of the FPD with pixel sizes of 48 x 48 microm, and the shifting dimension of an object in the horizontal direction ranged from 100 to 200 microm. At a shifting distance of 100 mum, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 83 microm. In embossed radiography of non-living animals, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in the kidney, and coronary arteries approximately 100 microm in diameter. PMID:20821133
Children's Use of Subtraction by Addition on Large Single-Digit Subtractions
ERIC Educational Resources Information Center
Peters, Greet; De Smedt, Bert; Torbeyns, Joke; Ghesquiere, Pol; Verschaffel, Lieven
2012-01-01
Subtractions of the type M - S = ? can be solved by various strategies, including subtraction by addition. In this study, we investigated children's use of subtraction by addition by means of reaction time analyses. We presented 106 third to sixth graders with 32 large non-tie single-digit problems in both subtraction (12 - 9 = .) and addition…
Switched-Capacitor Voltage Multiplier
NASA Technical Reports Server (NTRS)
Sridharan, Govind
1991-01-01
Dc-to-dc power converter multiplies input supply potential by factor of nearly 40. Design does not make use of transformers or inductors but effects voltage boost-up by capacitive energy transfer. Circuit primarily made up of banks of capacitors, connected by network of integrated-circuit relays. Converter functionally linear voltage amplifier with fixed gain figure. Bipolar in operation. Output fully floating, and excellent dc isolation between input and output terminals.
Planar diode multiplier chains for THz spectroscopy
NASA Technical Reports Server (NTRS)
Maiwald, Frank W.; Drouin, Brian J.; Pearson, John C.; Mehdi, Imran; Lewena, Frank; Endres, Christian; Winnewisser, Gisbert
2005-01-01
High-resolution laboratory spectroscopy is utilized as a diagnostic tool to determine noise and harmonic content of balanced [9]-[11] and unbalanced [12]-[14] multiplier designs. Balanced multiplier designs suppress unintended harmonics more than -20dB. Much smaller values were measured on unbalanced multipliers.
Hybrid Voltage-Multipliers Based Switching Power Converters
NASA Astrophysics Data System (ADS)
Rosas-Caro, Julio C.; Mayo-Maldonado, Jonathan C.; Vazquez-Bautista, Rene Fabian; Valderrabano-Gonzalez, Antonio; Salas-Cabrera, Ruben; Valdez-Resendiz, Jesus Elias
2011-08-01
This work presents a derivation of PWM DC-DC hybrid converters by combining traditional converters with the Cockcroft-Walton voltage multiplier, the voltage multiplier of each converter is driven with the same transistor of the basic topology; this fact makes the structure of the new converters very simple and provides high-voltage gain. The traditional topologies discussed are the boost, buck-boost, Cuk and SEPIC. They main features of the discussed family are: (i) high-voltage gain without using extreme duty cycles or transformers, which allow high switching frequency and (ii) low voltage stress in switching devices, along with modular structures, and more output levels can be added without modifying the main circuit, which is highly desirable in some applications such as renewable energy generation systems. It is shown how a multiplier converter can become a generalized topology and how some of the traditional converters and several state-of-the-art converters can be derived from the generalized topologies and vice-versa. All the discussed converters were simulated, additionally experimental results are provided with an interleaved multiplier converter.
Deconstructing Calculation Methods Part 2: Subtraction
ERIC Educational Resources Information Center
Thompson, Ian
2007-01-01
In this second of a series of four articles, the author deconstructs the primary national strategy's (PNS) approach to written subtraction. The approach to subtraction is divided into three stages: using the empty number line; partitioning; and expanded layout leading to column methods (called "standard methods" in the consultation document). The…
Contexts for Column Addition and Subtraction
ERIC Educational Resources Information Center
Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen
2011-01-01
In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by designing…
A geometric approach to spectral subtraction
Lu, Yang; Loizou, Philipos C.
2008-01-01
The traditional power spectral subtraction algorithm is computationally simple to implement but suffers from musical noise distortion. In addition, the subtractive rules are based on incorrect assumptions about the cross terms being zero. A new geometric approach to spectral subtraction is proposed in the present paper that addresses these shortcomings of the spectral subtraction algorithm. A method for estimating the cross terms involving the phase differences between the noisy (and clean) signals and noise is proposed. Analysis of the gain function of the proposed algorithm indicated that it possesses similar properties as the traditional MMSE algorithm. Objective evaluation of the proposed algorithm showed that it performed significantly better than the traditional spectral subtractive algorithm. Informal listening tests revealed that the proposed algorithm had no audible musical noise. PMID:19122867
Digital subtraction angiography of the heart and lungs
Moodie, D.S.; Yiannikas, J.
1986-01-01
This book contains 12 chapters. Some of the chapter titles are: Physical Principles of Cardiac Digital Subtraction Angiography, The Use of Intravenous Digital Subtraction Angiography in Evaluating Patients with Complex Congenital Heart Disease, Exercise Intravenous Digital Subtraction Angiograpny, Cardiomyopathic and Cardiac Neoplastic Disease, Digital Subtraction Angiography in the Catheterization Laboratory, and Cardiac Digital Subtraction Angiography - Future Directions.
Optimization of background subtraction for image enhancement
NASA Astrophysics Data System (ADS)
Venetsky, Larry; Boczar, Ross; Lee-Own, Robert
2013-05-01
Analysis of foreground objects in scenery via image processing often involves a background subtraction process. This process aims to improve blob (connected component) content in the image. Quality blob content is often needed for defining regions of interest for object recognition and tracking. Three techniques are examined which optimize the background to be subtracted - genetic algorithm, an analytic solution based on convex optimization, and a related application of the CVX solver toolbox. These techniques are applied to a set of images and the results are compared. Additionally, a possible implementation architecture that uses multiple optimization techniques with subsequent arbitration to produce the best background subtraction is considered.
Entanglement entropy of subtracted geometry black holes
NASA Astrophysics Data System (ADS)
Cvetič, Mirjam; Saleem, Zain H.; Satz, Alejandro
2014-09-01
We compute the entanglement entropy of minimally coupled scalar fields on subtracted geometry black hole backgrounds, focusing on the logarithmic corrections. We notice that matching between the entanglement entropy of original black holes and their subtracted counterparts is only at the order of the area term. The logarithmic correction term is not only different but also, in general, changes sign in the subtracted case. We apply Harrison transformations to the original black holes and find out the choice of the Harrison parameters for which the logarithmic corrections vanish.
The utility of digital subtraction arteriography in peripheral vascular disease.
Kubal, W S; Crummy, A B; Turnipseed, W D
1983-01-01
Digital subtraction angiography (DSA), whether used in conjunction with intravenous or intraarterial injection techniques, has an established role in evaluation of peripheral vascular disease. Use of DSA can reduce the time, cost, and patient discomfort of the standard arteriographic study. While it is limited by field size and patient cooperation in some instances, the utility of noninvasive imaging using intravenous DSA and the added anatomic detail of intraarterial DSA for roadmapping and delineation of small distal vessels provide the basis for future integration of standard arteriographic and DSA methods in assessment of peripheral vascular disease. PMID:6228296
Serial multiplier arrays for parallel computation
NASA Technical Reports Server (NTRS)
Winters, Kel
1990-01-01
Arrays of systolic serial-parallel multiplier elements are proposed as an alternative to conventional SIMD mesh serial adder arrays for applications that are multiplication intensive and require few stored operands. The design and operation of a number of multiplier and array configurations featuring locality of connection, modularity, and regularity of structure are discussed. A design methodology combining top-down and bottom-up techniques is described to facilitate development of custom high-performance CMOS multiplier element arrays as well as rapid synthesis of simulation models and semicustom prototype CMOS components. Finally, a differential version of NORA dynamic circuits requiring a single-phase uncomplemented clock signal introduced for this application.
Keynesian multiplier versus velocity of money
NASA Astrophysics Data System (ADS)
Wang, Yougui; Xu, Yan; Liu, Li
2010-08-01
In this paper we present the relation between Keynesian multiplier and the velocity of money circulation in a money exchange model. For this purpose we modify the original exchange model by constructing the interrelation between income and expenditure. The random exchange yields an agent's income, which along with the amount of money he processed determines his expenditure. In this interactive process, both the circulation of money and Keynesian multiplier effect can be formulated. The equilibrium values of Keynesian multiplier are demonstrated to be closely related to the velocity of money. Thus the impacts of macroeconomic policies on aggregate income can be understood by concentrating solely on the variations of money circulation.
Shaw, C G; Plewes, D B
1986-08-01
The pulsed-injection method for measuring the velocity of blood flow in intraarterial digital subtraction angiography is described. With this technique, contrast material is injected at a pulsing frequency as high as 15 Hz, so that two or more boluses can be imaged simultaneously. The velocity of flow is determined by measuring the spacing between the boluses and multiplying it by the pulsing frequency. Results of tests with phantoms correlate well with flow measurements obtained with a graduated cylinder for velocities ranging from 8 to 60 cm/sec. The potential of the method for time-dependent velocity measurement has been demonstrated with simulated pulsatile flows. PMID:3523598
Open-loop digital frequency multiplier
NASA Technical Reports Server (NTRS)
Moore, R. C.
1977-01-01
Monostable multivibrator is implemented by using digital integrated circuits where multiplier constant is too large for conventional phase-locked-loop integrated circuit. A 400 Hz clock is generated by divide-by-N counter from 1 Hz timing reference.
Framework Resources Multiply Computing Power
NASA Technical Reports Server (NTRS)
2010-01-01
As an early proponent of grid computing, Ames Research Center awarded Small Business Innovation Research (SBIR) funding to 3DGeo Development Inc., of Santa Clara, California, (now FusionGeo Inc., of The Woodlands, Texas) to demonstrate a virtual computer environment that linked geographically dispersed computer systems over the Internet to help solve large computational problems. By adding to an existing product, FusionGeo enabled access to resources for calculation- or data-intensive applications whenever and wherever they were needed. Commercially available as Accelerated Imaging and Modeling, the product is used by oil companies and seismic service companies, which require large processing and data storage capacities.
A Cognitive Tool for Teaching the Addition/Subtraction of Common Fractions: A Model of Affordances
ERIC Educational Resources Information Center
Kong, Siu Cheung; Kwok, Lam For
2005-01-01
The aim of this research is to devise a cognitive tool for meeting the diverse needs of learners for comprehending new procedural knowledge. A model of affordances on teaching fraction equivalence for developing procedural knowledge for adding/subtracting fractions with unlike denominators was derived from the results of a case study of an initial…
A kinetic model for subtractive hybridization.
Milner, J J; Cecchini, E; Dominy, P J
1995-01-01
Nucleic acid sequences that differ in abundance between two populations (target sequences) can be cloned by multiple rounds of subtractive hybridization and amplification by PCR. These sequences can be cDNAs representing up-regulated mRNAs, or genomic DNAs from deletion mutants. We have derived an equation that describes the recovery of such sequences, and have used this to simulate the outcome of up to 10 rounds of subtractive hybridization and PCR amplification. When the model was tested by comparing its predictions with the published results from genomic and cDNA subtractions, the predictions of the model were generally in good agreement with the published data. We have modelled the outcomes of genomic subtractions, for a variety of genomes, and have used it to compare various strategies for enriching targets. The model predicts that for genomes of less than 5 x 10(8) bp, deletions of as small as 1 kbp should represent > 99% of the DNA after three to six rounds of hybridization (depending on the enrichment procedure). As genomes increase in size, the kinetics of hybridization become an important limiting factor. However, even for genomes as large as 3 x 10(9) bp, it should be possible to isolate deletions of 5 kbp using the appropriate conditions. These simulations suggest that such methods offer a realistic alternative to chromosome walking for identifying genomic deletions for which there are known phenotypes, thereby considerably reducing time and effort. For cDNA subtractive hybridization, the model predicts that after six rounds of hybridization, sequences that do not differ in abundance between the tester and driver populations (the background) will represent < 1% of the subtracted population, and even quite modestly upregulated cDNAs should be successfully enriched. Where several up-regulated cDNAs are present, the predicted final representation is dependent on both the initial abundance and the degree of up-regulation. PMID:7870584
Lotka-Volterra system with Volterra multiplier.
Gürlebeck, Klaus; Ji, Xinhua
2011-01-01
With the aid of Volterra multiplier, we study ecological equations for both tree system and cycle system. We obtain a set of sufficient conditions for the ultimate boundedness to nonautonomous n-dimensional Lotka-Volterra tree systems with continuous time delay. The criteria are applicable to cooperative model, competition model, and predator-prey model. As to cycle system, we consider a three-dimensional predator-prey Lotka-Volterra system. In order to get a condition under which the system is globally asymptotic stable, we obtain a Volterra multiplier, so that in a parameter region the system is with the Volterra multiplier it is globally stable. We have also proved that in regions in which the condition is not satisfied, the system is unstable or at least it is not globally stable. Therefore, we say that the three-dimensional cycle system is with global bifurcation.
WIDE BAND REGENERATIVE FREQUENCY DIVIDER AND MULTIPLIER
Laine, E.F.
1959-11-17
A regenerative frequency divider and multiplier having wide band input characteristics is presented. The circuit produces output oscillations having frequencies related by a fixed ratio to input oscillations over a wide band of frequencies. In accomplishing this end, the divider-multiplier includes a wide band input circuit coupled by mixer means to a wide band output circuit having a pass band related by a fixed ratio to that of the input circuit. A regenerative feedback circuit derives a fixed frequency ratio feedback signal from the output circuit and applies same to the mixer means in proper phase relation to sustain fixed frequency ratio oscillations in the output circuit.
Transactional Algorithm for Subtracting Fractions: Go Shopping
ERIC Educational Resources Information Center
Pinckard, James Seishin
2009-01-01
The purpose of this quasi-experimental research study was to examine the effects of an alternative or transactional algorithm for subtracting mixed numbers within the middle school setting. Initial data were gathered from the student achievement of four mathematics teachers at three different school sites. The results indicated students who…
Digital subtraction angiography: patient preparation and care.
Hunt, A H
1987-08-01
The use of digital subtraction angiography (DSA) is increasing. Nurses must be prepared to provide quality care to patients who have this relatively new method for radiographically studying the blood vessels. A description of DSA and its applications is provided. Patient preparation, assessment, teaching, and management are described. Complications of the procedure and their management are presented. PMID:2958568
Diagnosis of Subtraction Bugs Using Bayesian Networks
ERIC Educational Resources Information Center
Lee, Jihyun; Corter, James E.
2011-01-01
Diagnosis of misconceptions or "bugs" in procedural skills is difficult because of their unstable nature. This study addresses this problem by proposing and evaluating a probability-based approach to the diagnosis of bugs in children's multicolumn subtraction performance using Bayesian networks. This approach assumes a causal network relating…
An experimental implementation of chemical subtraction.
Chen, Shao-Nong; Turner, Allison; Jaki, Birgit U; Nikolic, Dejan; van Breemen, Richard B; Friesen, J Brent; Pauli, Guido F
2008-03-13
A preparative analytical method was developed to selectively remove ("chemically subtract") a single compound from a complex mixture, such as a natural extract or fraction, in a single step. The proof of concept is demonstrated by the removal of pure benzoic acid (BA) from cranberry (Vaccinium macrocarpon Ait.) juice fractions that exhibit anti-adhesive effects versus uropathogenic Escherichia coli. Chemical subtraction of BA, representing a major constituent of the fractions, eliminates the potential in vitro interference of the bacteriostatic effect of BA on the E. coli anti-adherence action measured in bioassays. Upon BA removal, the anti-adherent activity of the fraction was fully retained, 36% inhibition of adherence in the parent fraction at 100mug/mL increased to 58% in the BA-free active fraction. The method employs countercurrent chromatography (CCC) and operates loss-free for both the subtracted and the retained portions as only liquid-liquid partitioning is involved. While the high purity (97.47% by quantitative (1)H NMR) of the subtracted BA confirms the selectivity of the method, one minor impurity was determined to be scopoletin by HR-ESI-MS and (q)HNMR and represents the first coumarin reported from cranberries. A general concept for the selective removal of phytoconstituents by CCC is presented, which has potential broad applicability in the biological evaluation of medicinal plant extracts and complex pharmaceutical preparations. PMID:18234463
Children's Profiles of Addition and Subtraction Understanding
ERIC Educational Resources Information Center
Canobi, Katherine H.
2005-01-01
The current research explored children's ability to recognize and explain different concepts both with and without reference to physical objects so as to provide insight into the development of children's addition and subtraction understanding. In Study 1, 72 7- to 9-year-olds judged and explained a puppet's activities involving three conceptual…
Children's Understanding of Addition and Subtraction Concepts
ERIC Educational Resources Information Center
Robinson, Katherine M.; Dube, Adam K.
2009-01-01
After the onset of formal schooling, little is known about the development of children's understanding of the arithmetic concepts of inversion and associativity. On problems of the form a+b-b (e.g., 3+26-26), if children understand the inversion concept (i.e., that addition and subtraction are inverse operations), then no calculations are needed…
Verification of IEEE Compliant Subtractive Division Algorithms
NASA Technical Reports Server (NTRS)
Miner, Paul S.; Leathrum, James F., Jr.
1996-01-01
A parameterized definition of subtractive floating point division algorithms is presented and verified using PVS. The general algorithm is proven to satisfy a formal definition of an IEEE standard for floating point arithmetic. The utility of the general specification is illustrated using a number of different instances of the general algorithm.
Temperature Effects in Varactors and Multipliers
NASA Technical Reports Server (NTRS)
East, J.; Mehdi, Imran
2001-01-01
Varactor diode multipliers are a critical part of many THz measurement systems. The power and efficiencies of these devices limit the available power for THz sources. Varactor operation is determined by the physics of the varactor device and a careful doping profile design is needed to optimize the performance. Higher doped devices are limited by junction breakdown and lower doped structures are limited by current saturation. Higher doped structures typically have higher efficiencies and lower doped structures typically have higher powers at the same operating frequency and impedance level. However, the device material properties are also a function of the operating temperature. Recent experimental evidence has shown that the power output of a multiplier can be improved by cooling the device. We have used a particle Monte Carlo simulation to investigate the temperature dependent velocity vs. electric field in GaAs. This information was then included in a nonlinear device circuit simulator to predict multiplier performance for various temperatures and device designs. This paper will describe the results of this analysis of temperature dependent multiplier operation.
Cleaning of contaminated channel electron multiplier arrays.
NASA Technical Reports Server (NTRS)
Harlow, F. E.; Hunter, W. R.
1972-01-01
Polymerized organic materials found in vacuum systems frequently contaminate the individual channels (which can be as small as 15 microns) of an oil-pumped channel electron multiplier array used as a vacuum UV- to visible-radiation conversion device. It is shown that exposure to an oxygen plasma is an effective means of decontaminating the channels, thereby restoring the sensitivity of the device.
Digital subtraction angiography in extremity trauma
Goodman, P.C.; Jeffrey, R.B. Jr.; Brant-Zawadzki, M.
1984-10-01
Digital subtraction angiography (DSA) may have considerable impact on the work-up of patients who have suffered trauma. The angiographic evaluation of vascular injuries can be accomplished rapidly and with minimal catheter use and manipulation, which is particularly important for those critically ill patients who have significant immobility because of multiple fractures. The authors retrospectively reviewed the digital subtraction angiograms in 50 consecutive cases of extremity trauma. The quality of the images in 44 of these permitted a confident diagnosis, the accuracy of which was confirmed by surgical or clinical follow-up. DSA reduces the time required to perform the procedure, the amount of contrast material injected, patient discomfort, and film cost. Its major disadvantage is the limited field size of the image intensifier.
Liquid-Crystal-Television Image Subtracters
NASA Technical Reports Server (NTRS)
Chao, Tien-Hsin; Liu, Hua-Kuang
1988-01-01
Two image-subtraction systems from output images that show differences between input images of two objects. First: differences appear as bright regions in otherwise dark output image. Second: differences and similarities shown by colors. All parts of two images processed simultaneously by optical components only; digital electronic processing of data not required. Concept offers potential for rapid, inexpensive comparison of images in such applications as automatic inspection, medical diagnosis, and robotic vision.
Blind foreground subtraction for intensity mapping experiments
NASA Astrophysics Data System (ADS)
Alonso, David; Bull, Philip; Ferreira, Pedro G.; Santos, Mário G.
2015-02-01
We make use of a large set of fast simulations of an intensity mapping experiment with characteristics similar to those expected of the Square Kilometre Array in order to study the viability and limits of blind foreground subtraction techniques. In particular, we consider three different approaches: polynomial fitting, principal component analysis (PCA) and independent component analysis (ICA). We review the motivations and algorithms for the three methods, and show that they can all be described, using the same mathematical framework, as different approaches to the blind source separation problem. We study the efficiency of foreground subtraction both in the angular and radial (frequency) directions, as well as the dependence of this efficiency on different instrumental and modelling parameters. For well-behaved foregrounds and instrumental effects, we find that foreground subtraction can be successful to a reasonable level on most scales of interest. We also quantify the effect that the cleaning has on the recovered signal and power spectra. Interestingly, we find that the three methods yield quantitatively similar results, with PCA and ICA being almost equivalent.
Subtractive Structural Modification of Morpho Butterfly Wings.
Shen, Qingchen; He, Jiaqing; Ni, Mengtian; Song, Chengyi; Zhou, Lingye; Hu, Hang; Zhang, Ruoxi; Luo, Zhen; Wang, Ge; Tao, Peng; Deng, Tao; Shang, Wen
2015-11-11
Different from studies of butterfly wings through additive modification, this work for the first time studies the property change of butterfly wings through subtractive modification using oxygen plasma etching. The controlled modification of butterfly wings through such subtractive process results in gradual change of the optical properties, and helps the further understanding of structural optimization through natural evolution. The brilliant color of Morpho butterfly wings is originated from the hierarchical nanostructure on the wing scales. Such nanoarchitecture has attracted a lot of research effort, including the study of its optical properties, its potential use in sensing and infrared imaging, and also the use of such structure as template for the fabrication of high-performance photocatalytic materials. The controlled subtractive processes provide a new path to modify such nanoarchitecture and its optical property. Distinct from previous studies on the optical property of the Morpho wing structure, this study provides additional experimental evidence for the origination of the optical property of the natural butterfly wing scales. The study also offers a facile approach to generate new 3D nanostructures using butterfly wings as the templates and may lead to simpler structure models for large-scale man-made structures than those offered by original butterfly wings.
Novel fast multiplier implemented using FPGA
NASA Astrophysics Data System (ADS)
Jabłoński, Janusz; Wegrzyn, Marek
2015-09-01
In the paper, the solution dedicated for FPGA devices of a synthesis of parallel multiplication systems with the alternative approach, called mutual exclusion, for results of partial products is presented. There are proposed a reducer with the factor 4:2 for parallel multipliers, based on Wallace tree structures, that are dedicated for 4-input and 1-output Look-Up Table (LUT) function generator used in FPGA devices. The elaboration refers to the solution for multiplying using FPGAs the numbers of 4 and 8 bits. However it can be enlarged up to 16 and 32 bits. The proposed solution gives the opportunity to use the probability of conditional significant partial products and faster service - fewer logic levels for special cases of multiplication related to the specific values of the sums of partial product bits.
Integrated optic vector-matrix multiplier
Watts, Michael R.
2011-09-27
A vector-matrix multiplier is disclosed which uses N different wavelengths of light that are modulated with amplitudes representing elements of an N.times.1 vector and combined to form an input wavelength-division multiplexed (WDM) light stream. The input WDM light stream is split into N streamlets from which each wavelength of the light is individually coupled out and modulated for a second time using an input signal representing elements of an M.times.N matrix, and is then coupled into an output waveguide for each streamlet to form an output WDM light stream which is detected to generate a product of the vector and matrix. The vector-matrix multiplier can be formed as an integrated optical circuit using either waveguide amplitude modulators or ring resonator amplitude modulators.
Perdurance of multiply connected de Sitter space
NASA Astrophysics Data System (ADS)
González-Díaz, Pedro F.
1999-06-01
This paper deals with a study of the effects that spherically symmetric first-order metric perturbations and vacuum quantum fluctuations have on the stability of the multiply connected de Sitter spacetime recently proposed by Gott and Li. It is the main conclusion of this study that although such a spacetime is stable to the classical metric perturbations for any size of the nonchronal region, it is only stable against the quantum fluctuations of vacuum if the size of the multiply connected region is of the order of the Planck scale. Therefore, boundary conditions for the state of the universe based on the notion that the universe created itself in a regime where closed timelike curves were active and stable still appear to be physically and philosophically well supported as are those boundary conditions relying on the notion that the universe was created out of nothing.
QCD Condensates and Holographic Wilson Loops for Asymptotically AdS Spaces
Quevedo, R. Carcasses; Goity, Jose L.; Trinchero, Roberto C.
2014-02-01
The minimization of the Nambu-Goto (NG) action for a surface whose contour defines a circular Wilson loop of radius a placed at a finite value of the coordinate orthogonal to the border is considered. This is done for asymptotically AdS spaces. The condensates of dimension n = 2, 4, 6, 8, and 10 are calculated in terms of the coefficients in the expansion in powers of the radius a of the on-shell subtracted NG action for small a->0. The subtraction employed is such that it presents no conflict with conformal invariance in the AdS case and need not introduce an additional infrared scale for the case of confining geometries. It is shown that the UV value of the gluon condensates is universal in the sense that it only depends on the first coefficients of the difference with the AdS case.
Low-Jitter Digital Rate Multiplier
NASA Technical Reports Server (NTRS)
Katz, Richard B.; Rakow, Glenn P.
1993-01-01
Jitter in digital rate multiplier reduced by improved method involving use of two slightly different minor clock periods. Original application to divide measured period of spin of spacecraft into large number of equal subintervals, by counting cycles of master oscillator running at high frequency. Method also used to reduce jitter in other situations necessary to generate equal subintervals from synchronizing clock signal of arbitrary period. Particularly valuable in situations where synchronizing signals lost temporarily and where drift in analog circuit unacceptable.
Lagrange multipliers in theories of gravitation
Kichenassamy, S.
1986-05-01
In gravitatinal theories, P-italic-variation (independepent variation of metric and connection) and H-variation (variation of the metric alone) may be reconciled through C-italic-variation (use of Lagrange multipliers ..lambda.. in P-italic-variation). We extend C-italic-variation to fields coupled with gravitational field and elucidate the cases of vanishing ..lambda... We show that the interpretation of ..lambda.. as constraint reaction forces sheds new light on the structure of these theories; we are thus led to question the necessary of relating torsion to spin, and as an alternative to the theory of Dirac particles in Einstein-Cartan space-time, we propose in a Lorentzian space-time a theory in which Lagrange multipliers corresponding to the vanishing of torsion lead to the symmetrization of canonical energy-momentum tensor and avoid the Heisenberg-Pauli-type terms. Lagrange multipliers also serve to reduce the fourth-order differential equations of gravitational quadratic Lagrangians to second-order ones with additional field variables (a scalar P-italic and a traceless tensor P-italic-tilde/sub i//sub j/); this reduction helps to make precise the compatibility of these theories with General Relativity. Simple derivations are also given for Chern and Euler characteristics c-italic/sub 2/ and /sub Chi//sub 2/, and for other identities.
Automobile Industry Retail Price Equivalent and Indirect Cost Multipliers
This report develops a modified multiplier, referred to as an indirect cost (IC) multiplier, which specifically evaluates the components of indirect costs that are likely to be affected by vehicle modifications associated with environmental regulation. A range of IC multipliers a...
Podoshvedov, S. A.
2011-04-15
A method to generate Schroedinger cat states in free propagating optical fields based on the use of displaced states (or displacement operators) is developed. Some optical schemes with photon-added coherent states are studied. The schemes are modifications of the general method based on a sequence of displacements and photon additions or subtractions adjusted to generate Schroedinger cat states of a larger size. The effects of detection inefficiency are taken into account.
Intraarterial digital subtraction angiography of renal transplants
Picus, D.; Neeley, J.P.; McClennan, B.L.; Weyman, P.J.; Heiken, J.P.
1985-07-01
Twenty-four intraarterial digital subtraction angiography (IA-DSA) studies were performed in 23 renal transplant recipients for evaluation of possible postoperative complications. Ten patients had normal studies. Five patients had minimal (<50%) narrowing at the renal artery anastomosis and five had more severe stenoses. Three patients had vascular occlusions. IA-DSA results correlated well with findings at surgery and/or conventional angiography. The major advantage of IA-DSA is the small amount of contrast material needed to perform the study. IA-DSA is particularly well suited to the evaluation of vascular problems in renal transplant patients.
Pipeline active filter utilizing a booth type multiplier
NASA Technical Reports Server (NTRS)
Nathan, Robert (Inventor)
1987-01-01
Multiplier units of the modified Booth decoder and carry-save adder/full adder combination are used to implement a pipeline active filter wherein pixel data is processed sequentially, and each pixel need only be accessed once and multiplied by a predetermined number of weights simultaneously, one multiplier unit for each weight. Each multiplier unit uses only one row of carry-save adders, and the results are shifted to less significant multiplier positions and one row of full adders to add the carry to the sum in order to provide the correct binary number for the product Wp. The full adder is also used to add this product Wp to the sum of products .SIGMA.Wp from preceding multiply units. If m.times.m multiplier units are pipelined, the system would be capable of processing a kernel array of m.times.m weighting factors.
NASA Astrophysics Data System (ADS)
Anabalón, Andrés; Astefanesei, Dumitru; Choque, David
2016-11-01
We construct exact hairy AdS soliton solutions in Einstein-dilaton gravity theory. We examine their thermodynamic properties and discuss the role of these solutions for the existence of first order phase transitions for hairy black holes. The negative energy density associated to hairy AdS solitons can be interpreted as the Casimir energy that is generated in the dual filed theory when the fermions are antiperiodic on the compact coordinate.
A Mathematical Model for Suppression Subtractive Hybridization
Gadgil, Chetan; Rink, Anette; Beattie, Craig
2002-01-01
Suppression subtractive hybridization (SSH) is frequently used to unearth differentially expressed genes on a whole-genome scale. Its versatility is based on combining cDNA library subtraction and normalization, which allows the isolation of sequences of varying degrees of abundance and differential expression. SSH is a complex process with many adjustable parameters that affect the outcome of gene isolation.We present a mathematical model of SSH based on DNA hybridization kinetics for assessing the effect of various parameters to facilitate its optimization. We derive an equation for the probability that a particular differentially expressed species is successfully isolated and use this to quantify the effect of the following parameters related to the cDNA sample: (a) mRNA abundance; (b) partial sequence complementarity to other species; and (3) degree of differential expression. We also evaluate the effect of parameters related to the process, including: (a) reaction times; and (b) extent of driver excess used in the two hybridization reactions. The optimum set of process parameters for successful isolation of differentially expressed species depends on transcript abundance. We show that the reaction conditions have a significant effect on the occurrence of false-positives and formulate strategies to isolate specific subsets of differentially expressed genes. We also quantify the effect of non-specific hybridization on the false-positive results and present strategies for spiking cDNA sequences to address this problem. PMID:18629052
Coherent bremsstrahlung used for digital subtraction angiography
NASA Astrophysics Data System (ADS)
Überall, Herbert
2007-05-01
Digital subtraction angiography (DSA), also known as Dichromography, using synchrotron radiation beams has been developed at Stanford University (R. Hofstadter) and was subsequently taken over at the Brookhaven Synchrotron and later at Hamburg (HASYLAB) [see, e.g., W.R. Dix, Physik in unserer Zeit. 30 (1999) 160]. The imaging of coronary arteries is carried out with an iodine-based contrast agent which need not be injected into the heart. The radiation must be monochromatized and is applied above and below the K-edge of iodine (33.16 keV), with a subsequent digital subtraction of the two images. Monochromatization of the synchrotron radiation causes a loss of intensity of 10 -3. We propose instead the use of coherent bremsstrahlung [see, e.g., A.W. Saenz and H. Uberall, Phys. Rev. B25 (1982) 448] which is inherently monochromatic, furnishing a flux of 10 12 photon/sec. This requires a 10-20 MeV electron linac which can be obtained by many larger hospitals, eliminating the scheduling problems present at synchrotrons. The large, broad incoherent bremsstrahlung background underlying the monochromatic spike would lead to inadmissible overexposure of the patient. This problem can be solved with the use of Kumakhov's capillary optics [see e.g., S.B.Dabagov, Physics-Uspekhi 46 (2003) 1053]: the low-energy spiked radiation can be deflected towards the patient, while the higher energy incoherent background continues forward, avoiding the patient who is placed several meters from the source.
Total Variation Regularized Tensor RPCA for Background Subtraction From Compressive Measurements.
Cao, Wenfei; Wang, Yao; Sun, Jian; Meng, Deyu; Yang, Can; Cichocki, Andrzej; Xu, Zongben
2016-09-01
Background subtraction has been a fundamental and widely studied task in video analysis, with a wide range of applications in video surveillance, teleconferencing, and 3D modeling. Recently, motivated by compressive imaging, background subtraction from compressive measurements (BSCM) is becoming an active research task in video surveillance. In this paper, we propose a novel tensor-based robust principal component analysis (TenRPCA) approach for BSCM by decomposing video frames into backgrounds with spatial-temporal correlations and foregrounds with spatio-temporal continuity in a tensor framework. In this approach, we use 3D total variation to enhance the spatio-temporal continuity of foregrounds, and Tucker decomposition to model the spatio-temporal correlations of video background. Based on this idea, we design a basic tensor RPCA model over the video frames, dubbed as the holistic TenRPCA model. To characterize the correlations among the groups of similar 3D patches of video background, we further design a patch-group-based tensor RPCA model by joint tensor Tucker decompositions of 3D patch groups for modeling the video background. Efficient algorithms using the alternating direction method of multipliers are developed to solve the proposed models. Extensive experiments on simulated and real-world videos demonstrate the superiority of the proposed approaches over the existing state-of-the-art approaches. PMID:27305675
Educational intervention with multiply handicapped preschool children.
Kaminer, R K; Chinitz, S P
1982-02-01
A study was conducted to objectively measure changes in functioning of multiply handicapped children in a specialized nursery school program. The study population consisted of the 18 children who entered the program in the study year. A quantitative teacher rating scale was developed, tested, and found to be reliable. Significant improvements were demonstrated in interaction, communication, and task orientation after 3 months and in self-care after 6 months. There was no measurable change in motor performance, and the intellectual functioning of the children remained in the same diagnostic category as at the outset. The study documented improvement on social competence of multiply handicapped children enrolled in a preschool program with minimal parental involvement. The teacher rating scale was found to be useful in measuring social functioning in a school setting for a young population with a limited range of possible achievements. Teachers proved to be reliable evaluators of their pupils. To measure social and interactional parameters, it appears necessary to have both a standardized instrument and an informed observer who knows the child's daily functioning. PMID:6460491
Language, visual working memory, and dot subtraction: What counts?
Briere, Jennifer L; Campbell, Jamie I D
2016-03-01
To investigate cognitive factors affecting subtraction of visual objects, we adapted the dot subtraction task developed by Pica, Lemer, Izard, and Dehaene (2004), who used it to investigate calculation by the Mundurukú, an indigene group in Brazil that has a limited number word vocabulary. In the dot subtraction task, briefly displayed arrays of moving dots are used to represent the quantities for subtraction. We tested 40 Canadian university students' dot enumeration, Arabic digit subtraction, visual working memory, and performance on the dot subtraction task with dot display durations of 2, 1.5, 1, and .5 s. In the 2 s condition, error rates were uniformly low, whereas in the .5 s condition, error rates increased sharply as the minuend increased from 4 to 8, as was observed with the Mundurukú. Individual differences in dot subtraction accuracy were predicted by dot enumeration skill with longer dot display durations but were predicted by visual working memory efficiency with shorter durations. Pica et al. (2004) attributed the Mundurukú participants' very poor subtraction to the absence of counting words, but our results show that a shift to reliance on visual working memory is a nonlinguistic factor that comes into play in the dot subtraction task when time to encode the dot arrays is limited.
ERIC Educational Resources Information Center
UCLA IDEA, 2012
2012-01-01
Value added measures (VAM) uses changes in student test scores to determine how much "value" an individual teacher has "added" to student growth during the school year. Some policymakers, school districts, and educational advocates have applauded VAM as a straightforward measure of teacher effectiveness: the better a teacher, the better students…
Astronomical Image Subtraction by Cross-Convolution
NASA Astrophysics Data System (ADS)
Yuan, Fang; Akerlof, Carl W.
2008-04-01
In recent years, there has been a proliferation of wide-field sky surveys to search for a variety of transient objects. Using relatively short focal lengths, the optics of these systems produce undersampled stellar images often marred by a variety of aberrations. As participants in such activities, we have developed a new algorithm for image subtraction that no longer requires high-quality reference images for comparison. The computational efficiency is comparable with similar procedures currently in use. The general technique is cross-convolution: two convolution kernels are generated to make a test image and a reference image separately transform to match as closely as possible. In analogy to the optimization technique for generating smoothing splines, the inclusion of an rms width penalty term constrains the diffusion of stellar images. In addition, by evaluating the convolution kernels on uniformly spaced subimages across the total area, these routines can accommodate point-spread functions that vary considerably across the focal plane.
Adaptive thresholding of digital subtraction angiography images
NASA Astrophysics Data System (ADS)
Sang, Nong; Li, Heng; Peng, Weixue; Zhang, Tianxu
2005-10-01
In clinical practice, digital subtraction angiography (DSA) is a powerful technique for the visualization of blood vessels in the human body. Blood vessel segmentation is a main problem for 3D vascular reconstruction. In this paper, we propose a new adaptive thresholding method for the segmentation of DSA images. Each pixel of the DSA images is declared to be a vessel/background point with regard to a threshold and a few local characteristic limits depending on some information contained in the pixel neighborhood window. The size of the neighborhood window is set according to a priori knowledge of the diameter of vessels to make sure that each window contains the background definitely. Some experiments on cerebral DSA images are given, which show that our proposed method yields better results than global thresholding methods and some other local thresholding methods do.
Digital subtraction angiography: overview of technical principles.
Harrington, D P; Boxt, L M; Murray, P D
1982-10-01
The rapid development of equipment for digital subtraction angiography (DSA) has created a new diagnostic imaging method, the limits of which have not been scientifically determined. Yet through aggressive marketing, the technique is already beginning to permeate radiologic practice. The radiologist requires technical understanding of the instrumentation for informed judgment on clinical applications. DSA depends on the mating of high-resolution image-intensifier and television technology with computerized information manipulation and storage. In this overview, the individual components of the system are analyzed, from the generator to the image intensifier to the television system to the associated computer. By examining the role of each component, the current limitations and the areas of possible future development of DSA can be understood. This provides a basis for dealing with current technology and for evaluating the rapid technological changes that will occur over the next few years. PMID:6751053
On multipliers of Fourier series in the Lorentz space
NASA Astrophysics Data System (ADS)
Ydyrys, Aizhan Zh.; Tleukhanova, Nazerke T.
2016-08-01
We study the multipliers of Fourier series on the Lorentz spaces, in particular, the sufficient conditions for a sequence of complex numbers {λk}k∈Z in order to make it a multiplier of trigonometric Fourier series of space Lp,r [0; 1] in the Lq,r [0; 1]. In the paper there is a new multipliers theorem which is supplement of the well-known theorems, and given a counterexample.
Multiplier Accounting of Indian Mining Industry--The Concept
NASA Astrophysics Data System (ADS)
Hussain, A.; Karmakar, N. C.
2015-04-01
Input-output multipliers are indicators used for predicting the total impact on an economy due to the changes in its industrial demand and output. Also, input-output tables provide detailed dissection of the intermediate transactions in an economy. The aim of the paper is to put forward a basic framework of input-output economics as well as the multiplier concept. The outline of the methodology for calculating the multiplier associated with Indian mining industry is also presented.
Four-gate transistor analog multiplier circuit
NASA Technical Reports Server (NTRS)
Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)
2011-01-01
A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.
Multiplier-continuation algorthms for constrained optimization
NASA Technical Reports Server (NTRS)
Lundberg, Bruce N.; Poore, Aubrey B.; Bing, Yang
1989-01-01
Several path following algorithms based on the combination of three smooth penalty functions, the quadratic penalty for equality constraints and the quadratic loss and log barrier for inequality constraints, their modern counterparts, augmented Lagrangian or multiplier methods, sequential quadratic programming, and predictor-corrector continuation are described. In the first phase of this methodology, one minimizes the unconstrained or linearly constrained penalty function or augmented Lagrangian. A homotopy path generated from the functions is then followed to optimality using efficient predictor-corrector continuation methods. The continuation steps are asymptotic to those taken by sequential quadratic programming which can be used in the final steps. Numerical test results show the method to be efficient, robust, and a competitive alternative to sequential quadratic programming.
Analysis of Variance of Multiply Imputed Data.
van Ginkel, Joost R; Kroonenberg, Pieter M
2014-01-01
As a procedure for handling missing data, Multiple imputation consists of estimating the missing data multiple times to create several complete versions of an incomplete data set. All these data sets are analyzed by the same statistical procedure, and the results are pooled for interpretation. So far, no explicit rules for pooling F-tests of (repeated-measures) analysis of variance have been defined. In this paper we outline the appropriate procedure for the results of analysis of variance for multiply imputed data sets. It involves both reformulation of the ANOVA model as a regression model using effect coding of the predictors and applying already existing combination rules for regression models. The proposed procedure is illustrated using three example data sets. The pooled results of these three examples provide plausible F- and p-values.
Spin Transport in Multiply Connected Fractal Conductors
NASA Astrophysics Data System (ADS)
Lee, Bo-Ray; Chang, Ching-Ray; Klik, Ivo
2014-12-01
We consider spin and charge transport in a Sierpinski planar carpet; the interest here is its unique geometry. We analyze the fractal conductor as a combination of multiply connected quantum wires, and we observe the evolution of the transmission envelope in different fractal generations. For a fractal conductor dominated by resonant modes the transmission is characterized by strong fluctuations and conduction gaps. We show that charge and spin transport have different responses both to the presence of defects and to applied bias. At a high bias, or in a high-order fractal generation, spin accumulation is separated from charge accumulation because the larger drift velocity needs a longer polarization length, and the sample may turn into an insulator by the action of the defects. Our results are calculated numerically using the Keldysh Green function within the tight-binding framework.
Calibration System for SLC 476MHz to 2856MHz Multipliers
Akre, Ron; /SLAC
2011-08-26
The two mile long Main Drive Line (MDL) distributes 476MHz at each of the 31 sectors along its length. Each of the 31 sectors has a six times multiplier which drives the 2856MHz phase reference system for that sector. This system is used to set and maintain phase of the accelerator structures over time. During previous runs significant down time resulted from sector phasing which was required after multiplier replacement. A system was designed to calibrate the phase of the 476MHz input to the phase of the 2856MHz output of the multiplier units. This enabled multipliers to be replaced without rephasing sectors.
When Should We Teach Regrouping in Addition and Subtraction.
ERIC Educational Resources Information Center
Engelhardt, Jon M.; Usnick, Virginia
1991-01-01
Presented are the results of two pilot studies about multidigit addition and subtraction. The results are discussed in relation to possible alternative sequences in the teaching of addition and subtraction and the relationship between basic fact mastery and numeration concept attainment. (CW)
Developing a Model to Support Students in Solving Subtraction
ERIC Educational Resources Information Center
Murdiyani, Nila Mareta; Zulkardi; Putri, Ratu Ilma Indra; van Eerde, Dolly; van Galen, Frans
2013-01-01
Subtraction has two meanings and each meaning leads to the different strategies. The meaning of "taking away something" suggests a direct subtraction, while the meaning of "determining the difference between two numbers" is more likely to be modeled as indirect addition. Many prior researches found that the second meaning and…
Fostering First-Graders' Fluency with Basic Subtraction Combinations
ERIC Educational Resources Information Center
Baroody, Arthur J.; Purpura, David J.; Eiland, Michael D.; Reid, Erin E.
2012-01-01
Subtraction combinations are particularly challenging for children to learn (Kraner, 1980; Smith, 1921; see Cowan, 2003, for a review). This study examines whether the group of children receiving the "experimental subtraction-as-addition" training outperform the "control" group, which received training on a different reasoning strategy involving…
A Proposed Instructional Theory for Integer Addition and Subtraction
ERIC Educational Resources Information Center
Stephan, Michelle; Akyuz, Didem
2012-01-01
This article presents the results of a 7th-grade classroom teaching experiment that supported students' understanding of integer addition and subtraction. The experiment was conducted to test and revise a hypothetical learning trajectory so as to propose a potential instructional theory for integer addition and subtraction. The instructional…
Improved Algorithm For Finite-Field Normal-Basis Multipliers
NASA Technical Reports Server (NTRS)
Wang, C. C.
1989-01-01
Improved algorithm reduces complexity of calculations that must precede design of Massey-Omura finite-field normal-basis multipliers, used in error-correcting-code equipment and cryptographic devices. Algorithm represents an extension of development reported in "Algorithm To Design Finite-Field Normal-Basis Multipliers" (NPO-17109), NASA Tech Briefs, Vol. 12, No. 5, page 82.
The Multiply Imaged Strongly Lensed Supernova Refsdal
NASA Astrophysics Data System (ADS)
Kelly, Patrick
2016-01-01
In 1964, Sjur Refsdal first considered the possibility that the light from a background supernova could traverse multiple paths around a strong gravitational lens towards us. He showed that the arrival times of the supernova's light would depend on the cosmic expansion rate, as well as the distribution of matter in the lens. I will discuss the discovery of the first such multiply imaged supernova, which exploded behind the MACS J1149.6+2223 galaxy cluster. We have obtained Hubble Space Telescope grism and ground-based spectra of the four images of the supernova, which form an Einstein Cross configuration around an elliptical cluster member. These spectra as well as rest-frame optical light curves have allowed us to learn about the properties of the peculiar core-collapse supernova explosion, and contain information about the lenses' matter distribution as well as their stellar populations. A delayed image of the supernova is expected close to the galaxy cluster center as early as Fall 2015, and will serve as an unprecedented probe of the potential of a massive galaxy cluster.
Photoelectron Spectroscopy of Multiply Charged Anions
Wang, Xue B.; Wang, Lai S.
2009-07-01
Multiply charged anions (MCA’s) are common in the condensed phases, but are challenging to study in the gas phase. An experimental technique coupling photoelectron spectroscopy (PES) with electrospray ionization (ESI) has been developed to investigate properties of free MCA’s in the gas phase. In this article, the principles of this technique, and some initial findings about the intrinsic properties of MCA’s are reviewed. Examples chosen include the observation of the repulsive Coulomb barrier that exists universally in MCA’s and its effects on the dynamic stability and photoelectron spectroscopy of MCA’s. Solvation and solvent stabilization of MCA’s has been studied in the gas phase and will also be discussed. A second generation low-temperature ESI-PES apparatus has been developed, which allows ion temperatures to be controlled between 10 to 350 K. New results from the low-temperature ESI-PES instrument will also be reviewed, including doubly charged fullerene anions, inorganic metal complexes, and temperature-induced conformation changes of complex anions.
[Digital subtraction radiography for the detection of periodontal bone changes].
Mera, T
1989-03-01
This study was performed to evaluate the efficacy of digital subtraction radiography in detecting alveolar bone changes. In order to test the sensitivity of quantitative evaluation by subtraction radiography, a copper equivalent thickness obtained from digitized radiographs was compared with the actual mineral content of bone phantoms with 15 different minerals and 25 bone specimens. Results demonstrated that the copper equivalent thickness correlated well with the actual mineral content (bone phantoms: gamma s = 1.0, bone specimens: gamma s = 0.985). In order to test the ability of digitized subtraction radiography in assessing alveolar bone changes in vivo, subtraction images were compared with histological features. The experimental angular bony defects were treated with conservative periodontal therapy in 3 monkeys. The standardized radiographs were taken longitudinally after therapy, and subtraction images were made from the sequentially obtained radiographs. In addition, for fluorescent histomorphometrical evaluations of new bone formations, the animals were dosed with oxytetracycline, calsein solution and arizarin complex solution. Radiographic and histological evaluations were scheduled to provide healing periods of 2, 3, 4, 5, 6 and 9 weeks after periodontal therapy. Subtraction radiography offered an objective method to follow histological changes of alveolar bone, and the copper equivalent thickness obtained from subtraction radiographs correlated with the histometric bone volume (gamma s = 0.9023, p less than 0.01). The results of these studies indicated that subtraction radiography was useful in monitoring alveolar bone changes associated with periodontal disease and treatment and that the quanitative measurement of periodontal bone changes by subtraction radiography was feasible. PMID:2517790
Nucleon-nucleon scattering within a multiple subtractive renormalization approach
Timoteo, V. S.; Frederico, T.; Delfino, A.; Tomio, Lauro
2011-06-15
We present a methodology to renormalize the nucleon-nucleon interaction in momentum space, using a recursive multiple subtraction approach that prescinds from a cutoff regularization, to construct the kernel of the scattering equation. The subtracted scattering equation is solved with the next-leading-order and next-to-next-leading-order interactions. The results are presented for all partial waves up to j=2, fitted to low-energy experimental data. In this renormalization group invariant approach, the subtraction energy emerges as a renormalization scale and the momentum associated with it comes to be about the QCD scale ({Lambda}{sub QCD}), irrespectively to the partial wave.
Bhatia, Mona; Rosset, Antoine; Platon, Alexandra; Didier, Dominique; Becker, Christoph D; Poletti, Pierre-Alexandre
2010-01-01
Computed tomographic angiography (CTA) is a frequent noninvasive alternative to digital subtraction angiography. We previously reported the development of a new subtraction software to overcome limitations of adjacent bone and calcification in CT angiographic subtraction. Our aim was to further develop and improve this fast and automated computerized software, universally available for free use and compatible with most CT scanners, thus enabling better delineation of vascular structures, artifact reduction, and shorter reading times with potential clinical benefits. This computer-based free software will be available as an open source in the next release of OsiriX at the Web site http://www.osirix-viewer.com.
Image Subtraction by Holographic Storage in Photorefractive BTO Crytals
NASA Astrophysics Data System (ADS)
Zhivkova, Svetla; Miteva, Margarita
1990-04-01
Holographic subtraction of two images was first realized by Gabor et al-1 by using a successive recording of the two images with a 180 degree phase shift between them and subsequent readout of the composite hologram. Other techniques for image subtraction are proposed2-5 . In Ref. 2 the ,rr phase shift between the image complex fields is ensured by spatially modulation of the images by periodic waves that are themselves 180 deg out of phase. Phase conjugation and Stokes' relation are also used3'4 . In Ref. 5 subtraction is fulfilled by the help of two orthogonal lineary polarized waves.
Gas Electron Multiplier (GEM) Chamber Characteristics Test
Yu, Jaehoon; White, Andy; Park, Seongtae; Hahn, Changhie; Baldeloma, Edwin; Tran, Nam; McIntire, Austin; Soha, Aria; /Fermilab
2011-01-11
Gas Electron Multipliers (GEMs) have been used in many HEP experiments as tracking detectors. They are sensitive to X-rays which allows use beyond that of HEP. The UTA High Energy group has been working on using GEMs as the sensitive gap detector in a DHCAL for the ILC. The physics goals at the ILC put a stringent requirement on detector performance. Especially the precision required for jet mass and positions demands an unprecedented jet energy resolution to hadronic calorimeters. A solution to meet this requirement is using the Particle Flow Algorithm (PFA). In order for PFA to work well, high calorimeter granularity is necessary. Previous studies based on GEANT simulations using GEM DHCAL gave confidence on the performance of GEM in the sensitive gap in a sampling calorimeter and its use as a DHCAL in PFA. The UTA HEP team has built several GEM prototype chambers, including the current 30cm x 30cm chamber integrated with the SLAC-developed 64 channel kPiX analog readout chip. This chamber has been tested on the bench using radioactive sources and cosmic ray muons. In order to have fuller understanding of various chamber characteristics, the experiments plan to expose 1-3 GEM chambers of dimension 35cm x 35cm x 5cm with 1cm x 1cm pad granularity with 64 channel 2-D simultaneous readout using the kPiX chip. In this experiment the experiments pan to measure MiP signal height, chamber absolute efficiencies, chamber gain versus high voltage across the GEM gap, the uniformity of the chamber across the 8cm x 8cm area, cross talk and its distance dependence to the triggered pad, chamber rate capabilities, and the maximum pad occupancy rate.
Soft-collinear factorization and zero-bin subtractions
Chiu Juiyu; Fuhrer, Andreas; Kelley, Randall; Manohar, Aneesh V.; Hoang, Andre H.
2009-03-01
We study the Sudakov form factor for a spontaneously broken gauge theory using a (new) {delta}-regulator. To be well defined, the effective theory requires zero-bin subtractions for the collinear sectors. The zero-bin subtractions depend on the gauge boson mass M and are not scaleless. They have both finite and 1/{epsilon} contributions and are needed to give the correct anomalous dimension and low-scale matching contributions. We also demonstrate the necessity of zero-bin subtractions for soft-collinear factorization. We find that after zero-bin subtractions the form factor is the sum of the collinear contributions minus a soft mass-mode contribution, in agreement with a previous result of Idilbi and Mehen in QCD. This appears to conflict with the method-of-regions approach, where one gets the sum of contributions from different regions.
Background Subtraction for Automated Multisensor Surveillance: A Comprehensive Review
NASA Astrophysics Data System (ADS)
Cristani, Marco; Farenzena, Michela; Bloisi, Domenico; Murino, Vittorio
2010-12-01
Background subtraction is a widely used operation in the video surveillance, aimed at separating the expected scene (the background) from the unexpected entities (the foreground). There are several problems related to this task, mainly due to the blurred boundaries between background and foreground definitions. Therefore, background subtraction is an open issue worth to be addressed under different points of view. In this paper, we propose a comprehensive review of the background subtraction methods, that considers also channels other than the sole visible optical one (such as the audio and the infrared channels). In addition to the definition of novel kinds of background, the perspectives that these approaches open up are very appealing: in particular, the multisensor direction seems to be well-suited to solve or simplify several hoary background subtraction problems. All the reviewed methods are organized in a novel taxonomy that encapsulates all the brand-new approaches in a seamless way.
An auto-adaptive background subtraction method for Raman spectra
NASA Astrophysics Data System (ADS)
Xie, Yi; Yang, Lidong; Sun, Xilong; Wu, Dewen; Chen, Qizhen; Zeng, Yongming; Liu, Guokun
2016-05-01
Background subtraction is a crucial step in the preprocessing of Raman spectrum. Usually, parameter manipulating of the background subtraction method is necessary for the efficient removal of the background, which makes the quality of the spectrum empirically dependent. In order to avoid artificial bias, we proposed an auto-adaptive background subtraction method without parameter adjustment. The main procedure is: (1) select the local minima of spectrum while preserving major peaks, (2) apply an interpolation scheme to estimate background, (3) and design an iteration scheme to improve the adaptability of background subtraction. Both simulated data and Raman spectra have been used to evaluate the proposed method. By comparing the backgrounds obtained from three widely applied methods: the polynomial, the Baek's and the airPLS, the auto-adaptive method meets the demand of practical applications in terms of efficiency and accuracy.
Improvements in floating point addition/subtraction operations
Farmwald, P.M.
1984-02-24
Apparatus is described for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.
Subtractive cloning: new genes for studying inflammatory disorders.
Rebrikov, Denis; Desai, Sejal; Kogan, Yakov N; Thornton, Angela M; Diatchenko, Luda
2002-12-01
Understanding of the biology of interaction between pathogens and host is the central question in studying inflammatory disorders. Subtractive DNA cloning is one of the most efficient and comprehensive methods available for identifying eukaryotic genes regulated under specific physiological conditions, including inflammation and host response. Here we explore the utility of subtractive DNA cloning and describe suppression subtractive hybridization (SSH), a polymerase chain reaction (PCR)-based DNA subtraction method that has been developed and evolved in our labs over several years. The SSH method possesses a number of advantages as compared to other subtractive cloning techniques, making it one of the most adventitious methods for cloning differentially expressed genes. Besides isolation of differentially expressed eukaryotic mRNAs, subtractive DNA cloning can be used to identify genes that are differentially expressed between diverse bacterial species. These genes can be of great interest, as some may encode strain-specific traits such as drug resistance, or bacterial surface proteins involved in determining the virulence of a particular strain. Other genes may be useful as markers for epidemiological or evolutionary studies. To demonstrate the potential of the SSH technique, we describe here the comprehensive characterization of 2 SSH subtracted libraries constructed in our laboratories. One library was created using eukaryotic cDNA subtraction and is specific for mRNAs up-regulated in CD25 positive cells from mouse lymph nodes as compared to CD25 negative cells. The second subtracted library is specific for a methicillin-resistant Staphylococcus aureus bacterial strain, but not in a methicillin-sensitive strain. The bacterial genomes of these 2 strains have been completely sequenced and this second library provides an excellent reference for testing the ability of SSH to recover all strain-specific gene content. The analysis of these 2 subtracted libraries
A dissociation between addition and subtraction with written calculation.
McNeil, J E; Warrington, E K
1994-06-01
A patient with a severe dyscalculia and a mild arabic number dyslexia is described. He could perform simple addition and subtraction sums with oral presentation. However with written arabic number sums he was impaired with addition but not with subtraction. These findings require modifications to current models of arithmetic processing which have suggested that numerical inputs are converted into abstract internal representations before arithmetical processing can occur. PMID:8084426
Nonclassicality of a photon-subtracted Gaussian field
Kim, M.S.; Park, E.; Knight, P.L.; Jeong, H.
2005-04-01
We investigate the nonclassicality of a photon-subtracted Gaussian field, which was produced in a recent experiment, using negativity of the Wigner function and the nonexistence of well-behaved positive P function. We obtain the condition to see negativity of the Wigner function for the case including the mixed Gaussian incoming field, the threshold photodetection and the inefficient homodyne measurement. We show how similar the photon-subtracted state is to a superposition of coherent states.
Grant, E.J.; Macey, D.J.; Bayouth, J.E.
1994-05-01
Dose estimates for organs and tumor volumes in radioimmunotherapy with I-131 frequently depend on in-vivo quantitation methods using planar Anger camera images. Compton scatter and collimator septal penetration result in overestimation of activity and dose. The objective of this study was to assess the effectiveness of a triple energy window subtraction method for quantitative imaging of I-131. The energy spectrum of I-131 was modeled as a superposition of the spectra of Cr-51 (320 keV) and Cs-137 (662 keV). Images were acquired with three adjacent 15% energy windows--photopeak(PP), upper scatter(US), and lower scatter(LS)--for small sources of these radionuclides. The PP window was centered at 364 keV for I-131 and Cs-137 and 320 keV for Cr-51. Three scatter multipliers were derived from analysis of count profiles of the Cs-137 and Cr-51 images, and used to sequentially remove septal penetration and scatter events included in the 364 keV photopeak of I-131. This method was tested by acquiring images of an abdominal phantom containing a liver, spleen and spherical {open_quotes}tumor{close_quotes} filled with different concentrations of I-131, both with and without background activity in the surrounding phantom. A body thickness attenuation compensation factor was applied to the geometric mean of the conjugate view counts using a narrow beam linear attenuation coefficient of 0.11 cm{sup -1}. With scatter subtraction, the accuracy and reproducibility of activity quantitation was improved because the background count density was more uniformly scored. Also, the influence of different activity concentrations in source organs relative to background on the accuracy of quantitation was removed, and the perimeters of organs were more clearly defined. This method has been used to provide improved dose estimates for I-131 labeled antibody therapy in breast cancer patients.
Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing
NASA Technical Reports Server (NTRS)
Bahr, Christopher J.; Horne, William C.
2015-01-01
An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.
ERIC Educational Resources Information Center
Cerron-Palomino Lopez, Alvaro
2010-01-01
This dissertation is a variationist account of two non-standard relative clause (RC) structures in Spanish: resumptive pronouns (RPs) and prepositional-phrase (PP) chopping. Previous typological studies considered RP explanations based on difficulty of processing (Hawkins, 1994), while Spanish-specific quantitative studies proposed a number of…
Bacino, Carlos A; Cheung, Sau-Wai
2010-05-01
The clinical implementation of array-based comparative genomic hybridization (aCGH) has allowed detection of copy number variations (CNVs) from megabases in size to those involving only a single exon. One major challenge that followed the clinical implementation of array CGH technology has been the interpretation of CNVs whose clinical significance can be elusive. The copy number gains resulting from genomic rearrangements are often more difficult to interpret than the copy number losses. Some of the CNV gains can be pathogenic, while others can be unrelated to disease since CNVs are often polymorphic in the normal population. The challenge faced by clinicians is how to differentiate between the disease causing CNVs and the nonpathogenic polymorphisms. Therefore, it is critical to systematically collect phenotypic information associated with CNVs and deposit it in searchable and publicly accessible databases. (c) 2010 Wiley-Liss, Inc.
Systolic multiplier for finite fields gf(2/sup m/)
Yeh, C.S.; Reed, I.S.
1983-01-01
A systolic architecture is developed for performing the product-sum computation, ab+c, in the finite field gf(2/sup m/) of 2/sup m/ elements, where a, b and c are arbitrary elements of gf(2/sup m/). The multiplier is a serial-in, serial-out, one-dimensional systolic array. This multiplier for gf(2/sup m/) requires m basic cells. The average time per computation of the multiplier is m time units if a number of computations are computed consecutively. To perform an isolated computation the multiplier requires 3m time units. The architecture is simple and regular and possesses the desirable properties of concurrency and modularity and is well suited for use. 10 references.
Sociophysics of sexism: normal and anomalous petrie multipliers
NASA Astrophysics Data System (ADS)
Eliazar, Iddo
2015-07-01
A recent mathematical model by Karen Petrie explains how sexism towards women can arise in organizations where male and female are equally sexist. Indeed, the Petrie model predicts that such sexism will emerge whenever there is a male majority, and quantifies this majority bias by the ‘Petrie multiplier’: the square of the male/female ratio. In this paper—emulating the shift from ‘normal’ to ‘anomalous’ diffusion—we generalize the Petrie model to a stochastic Poisson model that accommodates heterogeneously sexist men and woman, and that extends the ‘normal’ quadratic Petrie multiplier to ‘anomalous’ non-quadratic multipliers. The Petrie multipliers span a full spectrum of behaviors which we classify into four universal types. A variation of the stochastic Poisson model and its Petrie multipliers is further applied to the context of cyber warfare.
Quantum-well diode frequency multipliers - Varistor case
NASA Technical Reports Server (NTRS)
Batelaan, Paul D.; Tolmunen, Timo J.; Frerking, Margaret A.
1992-01-01
Local oscillators for heterodyne receivers at submillimeter wavelengths are typically made using a fundamental source followed by a harmonic frequency multiplier. An investigation of the required circuit embedding conditions for a possible new harmonic generator, the quantum-well resonant-tunneling diode, is summarized. A low-frequency multiplier has been tested that employs the resistive nonlinearity of the device as opposed to the reactive nonlinearity. The results show good agreement between practice and theory.
Comparison of iodine K-edge subtraction and fluorescence subtraction imaging in an animal system
NASA Astrophysics Data System (ADS)
Zhang, H.; Zhu, Y.; Bewer, B.; Zhang, L.; Korbas, M.; Pickering, I. J.; George, G. N.; Gupta, M.; Chapman, D.
2008-09-01
K-Edge Subtraction (KES) utilizes the discontinuity in the X-ray absorption across the absorption edge of the selected contrast element and creates an image of the projected density of the contrast element from two images acquired just above and below the K-edge of the contrast element. KES has proved to be powerful in coronary angiography, micro-angiography, bronchography, and lymphatic imaging. X-ray fluorescence imaging is a successful technique for the detection of dilute quantities of elements in specimens. However, its application at high X-ray energies (e.g. at the iodine K-edge) is complicated by significant Compton background, which may enter the energy window set for the contrast material's fluorescent X-rays. Inspired by KES, Fluorescence Subtraction Imaging (FSI) is a technique for high-energy (>20 keV) fluorescence imaging using two different incident beam energies just above and below the absorption edge of a contrast element (e.g. iodine). The below-edge image can be assumed as a "background" image, which includes Compton scatter and fluorescence from other elements. The above-edge image will contain nearly identical spectral content as the below-edge image but will contain the additional fluorescence of the contrast element. This imaging method is especially promising with thick objects with dilute contrast materials, significant Compton background, and/or competing fluorescence lines from other materials. A quality factor is developed to facilitate the comparison. The theoretical value of the quality factor sets the upper limit that an imaging method can achieve when the noise is Poisson limited. The measured value of this factor makes two or more imaging methods comparable. Using the Hard X-ray Micro-Analysis (HXMA) beamline at the Canadian Light Source (CLS), the techniques of FSI and KES were critically compared, with reference to radiation dose, image acquisition time, resolution, signal-to-noise ratios, and quality factor.
Albacete, Javier L.; Kovchegov, Yuri V.; Taliotis, Anastasios
2009-03-23
We calculate the total cross section for the scattering of a quark-anti-quark dipole on a large nucleus at high energy for a strongly coupled N = 4 super Yang-Mills theory using AdS/CFT correspondence. We model the nucleus by a metric of a shock wave in AdS{sub 5}. We then calculate the expectation value of the Wilson loop (the dipole) by finding the extrema of the Nambu-Goto action for an open string attached to the quark and antiquark lines of the loop in the background of an AdS{sub 5} shock wave. We find two physically meaningful extremal string configurations. For both solutions we obtain the forward scattering amplitude N for the quark dipole-nucleus scattering. We study the onset of unitarity with increasing center-of-mass energy and transverse size of the dipole: we observe that for both solutions the saturation scale Q{sub s} is independent of energy/Bjorken-x and depends on the atomic number of the nucleus as Q{sub s}{approx}A{sup 1/3}. Finally we observe that while one of the solutions we found corresponds to the pomeron intercept of {alpha}{sub P} = 2 found earlier in the literature, when extended to higher energy or larger dipole sizes it violates the black disk limit. The other solution we found respects the black disk limit and yields the pomeron intercept of {alpha}{sub P} = 1.5. We thus conjecture that the right pomeron intercept in gauge theories at strong coupling may be {alpha}{sub P} = 1.5.
Appearance of the canine meninges in subtraction magnetic resonance images.
Lamb, Christopher R; Lam, Richard; Keenihan, Erin K; Frean, Stephen
2014-01-01
The canine meninges are not visible as discrete structures in noncontrast magnetic resonance (MR) images, and are incompletely visualized in T1-weighted, postgadolinium images, reportedly appearing as short, thin curvilinear segments with minimal enhancement. Subtraction imaging facilitates detection of enhancement of tissues, hence may increase the conspicuity of meninges. The aim of the present study was to describe qualitatively the appearance of canine meninges in subtraction MR images obtained using a dynamic technique. Images were reviewed of 10 consecutive dogs that had dynamic pre- and postgadolinium T1W imaging of the brain that was interpreted as normal, and had normal cerebrospinal fluid. Image-anatomic correlation was facilitated by dissection and histologic examination of two canine cadavers. Meningeal enhancement was relatively inconspicuous in postgadolinium T1-weighted images, but was clearly visible in subtraction images of all dogs. Enhancement was visible as faint, small-rounded foci compatible with vessels seen end on within the sulci, a series of larger rounded foci compatible with vessels of variable caliber on the dorsal aspect of the cerebral cortex, and a continuous thin zone of moderate enhancement around the brain. Superimposition of color-encoded subtraction images on pregadolinium T1- and T2-weighted images facilitated localization of the origin of enhancement, which appeared to be predominantly dural, with relatively few leptomeningeal structures visible. Dynamic subtraction MR imaging should be considered for inclusion in clinical brain MR protocols because of the possibility that its use may increase sensitivity for lesions affecting the meninges.
Coherent motion sensitivity predicts individual differences in subtraction.
Boets, Bart; De Smedt, Bert; Ghesquière, Pol
2011-01-01
Recent findings suggest deficits in coherent motion sensitivity, an index of visual dorsal stream functioning, in children with poor mathematical skills or dyscalculia, a specific learning disability in mathematics. We extended these data using a longitudinal design to unravel whether visual dorsal stream functioning is able to predict individual differences in subsequent specific mathematical skills, i.e., single-digit subtraction and multiplication. We measured children's sensitivity to coherent motion in kindergarten (mean age: 5 years 8 months) and evaluated their subtraction and multiplication skills in third grade (mean age 8 years 3 months). Findings revealed an association between subtraction but not multiplication performance and coherent motion sensitivity. This association remained significant even when intellectual ability and reading ability were additionally controlled for. Subtractions are typically solved by means of quantity-based procedural strategies, which reliably recruit the intraparietal sulcus. Against the background of a neural overlap between the intraparietal sulcus and visual dorsal stream functioning, we hypothesize that low-level visuospatial mechanisms might set constraints on the development of quantity representations, which are used during calculation, particularly in subtraction. PMID:21324638
Magnification Embossed Radiography Utilizing Image-Shifting Subtraction Program
NASA Astrophysics Data System (ADS)
Akihiro Osawa,; Manabu Watanabe,; Eiichi Sato,; Hiroshi Matsukiyo,; Toshiyuki Enomoto,; Jiro Nagao,; Purkhet Abderyim,; Katsuo Aizawa,; Etsuro Tanaka,; Hidezo Mori,; Toshiaki Kawai,; Akira Ogawa,; Kiyomi Takahashi,; Shigehiro Sato,; Jun Onagawa,
2010-03-01
We developed an image-shifting subtraction program and carried out magnification embossed radiography (MER) utilizing single- and dual-energy subtractions. In particular, dual-energy subtraction was carried out to decrease the absorption contrast of unnecessary regions. The contrast resolution of the target region was increased by the use of subtraction software and a linear-contrast system in a flat-panel detector (FPD). The X-ray generator had a 100-μm-focus tube, and the subtractions were performed at tube voltages of 40 and 70 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. MER images with threefold magnification were obtained using the FPD with a pixel size of 48× 48 μm2, and the shifting dimensions of the imaged object in the horizontal and vertical directions ranged from 48 to 192 μm. At a shifting distance ranging from 48 to 144 μm, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 50 μm. In the MER of nonliving animals, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in blood vessels, and iodine-based microspheres in coronary arteries of approximately 100 μm diameter.
Embossed radiography utilizing an image-shifting subtraction program
NASA Astrophysics Data System (ADS)
Sato, Eiichi; Osawa, Akihiro; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Takahashi, Kiyomi; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun
2010-07-01
We developed an image-shifting subtraction program and carried out embossed radiography (ER) utilizing single- and dual-energy subtractions. In particular, dual-energy subtraction was carried out to decrease the absorption contrast of unnecessary regions. The contrast resolution of a target region was increased using the subtraction program and a linear-contrast system in a flat panel detector (FPD). The X-ray generator had a 100 μm-focus tube, and the subtractions were performed at tube voltages of 40 and 70 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. ER was achieved with cohesion imaging using the FPD with pixel sizes of 48×48 μm 2, and the shifting dimension of an object in the horizontal and vertical directions ranged from 48 to 96 μm. At a shifting distance of 96 μm, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 83 μm. In ER of animal phantoms, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in blood vessels, iodine-based microspheres in coronary arteries approximately 100 μm in diameter.
Magnification Embossed Radiography Utilizing Image-Shifting Subtraction Program
NASA Astrophysics Data System (ADS)
Osawa, Akihiro; Watanabe, Manabu; Sato, Eiichi; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Nagao, Jiro; Abderyim, Purkhet; Aizawa, Katsuo; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Ogawa, Akira; Takahashi, Kiyomi; Sato, Shigehiro; Onagawa, Jun
2010-03-01
We developed an image-shifting subtraction program and carried out magnification embossed radiography (MER) utilizing single- and dual-energy subtractions. In particular, dual-energy subtraction was carried out to decrease the absorption contrast of unnecessary regions. The contrast resolution of the target region was increased by the use of subtraction software and a linear-contrast system in a flat-panel detector (FPD). The X-ray generator had a 100-µm-focus tube, and the subtractions were performed at tube voltages of 40 and 70 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. MER images with threefold magnification were obtained using the FPD with a pixel size of 48×48 µm2, and the shifting dimensions of the imaged object in the horizontal and vertical directions ranged from 48 to 192 µm. At a shifting distance ranging from 48 to 144 µm, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 50 µm. In the MER of nonliving animals, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in blood vessels, and iodine-based microspheres in coronary arteries of approximately 100 µm diameter.
Sky background subtraction with fiber-fed spectrographs
NASA Astrophysics Data System (ADS)
Puech, M.; Rodrigues, M.; Yang, Y.; Flores, H.; Royer, F.; Disseau, K.; Gonçalves, T.; Hammer, F.; Cirasuolo, M.; Evans, C. J.; Li Causi, G.; Maiolino, R.; Melo, C.
2014-08-01
Fiber-fed spectrographs can now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached on such instruments has often been pinpointed as one of their major issues, in relation to difficulties in scattered light and flat-field corrections or throughput losses associated with fibers. Using technical time observations with FLAMES-GIRAFFE, two observing techniques, namely dual staring and cross beam switching modes, were tested and the resulting sky subtraction accuracy reached in both cases was quantified. Results indicate that an accuracy of 0.6% on the sky subtraction can be reached, provided that the cross beam switching mode is used. This is very encouraging regarding the detection of very faint sources with future fiber-fed spectrographs such as VLT/MOONS or E-ELT/MOSAIC.
Proposed smart integrated-optical preprocessor using holographic subtraction
NASA Technical Reports Server (NTRS)
Verber, C. M.; Vahey, D. W.
1979-01-01
The paper presents a proposed integrated-optical preprocessor with a holographic subtraction. It is based on an optical analog of a set of N analog voltages formed by passing an optical plane wave, confined in an electrooptic waveguide, under a set of N electrodes to which the voltages are applied; in the limit in which diffraction is ignored, the wavefront of the emerging guided wave will have superimposed upon it N discrete phase shifts. Processors which operate upon voltages encoded in this manner are being fabricated; they include a comparator in which incoming data are compared to a holographic record of the optical analog of a reference set, and a 'smart' system based upon holographic self-subtraction, in which the processor can independently adapt to changes in background information. The preprocessor operation is described in the screening, identification, and the self-subtraction modes, and implementation of devices in an integrated optical configuration is discussed.
Multiply imaged quasi-stellar objects in the Gaia survey
NASA Astrophysics Data System (ADS)
Finet, F.; Surdej, J.
2016-05-01
Aims: We report a study on the statistical properties of the multiply imaged quasi-stellar objects (QSOs) to be detected within the Gaia survey. Methods: We considered two types of potential deflectors, the singular isothermal sphere (SIS) and the singular isothermal ellipsoid (SIE), to estimate the number of multiply imaged quasars as well as the normalized distributions of the redshifts of the lensed sources and of their associated deflectors. We also investigated the distribution of the lensing events as a function of their angular size and apparent magnitude. We compared the Gaia survey for multiply imaged quasars to typical ground-based surveys and to an ideal survey that would be carried out with a perfect instrument from space. Results: Of the 6.64 × 105 QSOs brighter than G = 20 to be detected by Gaia, we expect the discovery of about 2886 multiply imaged sources, 450 of which are expected to be produced by a late-type galaxy. We expect only ~1600 of these multiply imaged quasars to have an angular separation between their images that is large enough to be resolved from seeing-limited observations, and ~80 of them to have more than two lensed images.
Animal experiments by K-edge subtraction angiography by using SR (abstract)
NASA Astrophysics Data System (ADS)
Anno, I.; Akisada, M.; Takeda, T.; Sugishita, Y.; Kakihana, M.; Ohtsuka, S.; Nishimura, K.; Hasegawa, S.; Takenaka, E.; Hyodo, K.; Ando, M.
1989-07-01
controlled by a mechanical ventilator. The respirations were held for several seconds when taking the images. Approximately 10 to 15 ml of 76% water soluble iodinated contrast medium (Urografin 76, Schering) was injected by an automatic electronic injector at the rate of approximately 10 ml/s. Three or four times injections were done so as not to exceed the normal renal excretion threshold. Intravenous drip infusion of saline (500 ml/2 h) was used to accelerate the washout of contrast medium via renal system. One hundred micrograms of nitroglycerin were administered, intravenously to dilate the coronary arteries, approximately 3 min prior to contrast injection. Sometimes we used 0.1 mg/kg of beta blockage agent (Propranorol) to decrease the heart rate. Subsequently, the heart rate of the dogs was decreased from approximately 200/s to 100/s. These techniques are commonly used in human examinations. Materials are positioned at left anterior oblique view. The sequential images are now detected above the iodine K edge by an image intensifier (RTP 9240F, Toshiba) and recorded at high signal-to-noise ratio analog video recording system (C1900, Hamamatsu Photonics, S/N 45 dB). Proximal coronary arteries are well visualized, however the distal portions are unsatisfactory, because of the overlapping of the contrast-filled dense heart chambers and pulmonary vessels. Bolus injection of contrast medium is also necessary, unless overlapping is inevitable, so are the same in conventional intravenous DSA. The energy above and below the K edge is now changed by tilting the angle of crystal, mechanically, so it has not sufficient speed to subtract the moving material. Real time A/D converter and frame buffering memories have not been available, until now. Even though there are many limitations in the hardware and many problems to overcome, our preliminary animal experiments allow us to have high expectations.
Spatial frequency multiplier with active linearly tapered slot antenna array
NASA Astrophysics Data System (ADS)
Simons, Rainee N.; Lee, Richard Q.
1994-02-01
A frequency multiplier with active linearly tapered slot antennas (LTSA's) has been demonstrated at the second harmonic frequency. In each antenna element, a GaAs monolithic microwave integrated circuit (MMIC) distributed amplifier is integrated with two LTSA's. The multiplier has a very wide bandwidth and large dynamic range. The fundamental-to-second harmonic conversion efficiency is 8.1 percent. The spatially combined second harmonic signal is 50 dB above the noise level. The design is suitable for constructing a large array using monolithic integration techniques.
Spatial frequency multiplier with active linearly tapered slot antenna array
NASA Technical Reports Server (NTRS)
Simons, Rainee N.; Lee, Richard Q.
1994-01-01
A frequency multiplier with active linearly tapered slot antennas (LTSA's) has been demonstrated at the second harmonic frequency. In each antenna element, a GaAs monolithic microwave integrated circuit (MMIC) distributed amplifier is integrated with two LTSA's. The multiplier has a very wide bandwidth and large dynamic range. The fundamental-to-second harmonic conversion efficiency is 8.1 percent. The spatially combined second harmonic signal is 50 dB above the noise level. The design is suitable for constructing a large array using monolithic integration techniques.
High performance dc-dc conversion with voltage multipliers
NASA Technical Reports Server (NTRS)
Harrigill, W. T.; Myers, I. T.
1974-01-01
The voltage multipliers using capacitors and diodes first developed by Cockcroft and Walton in 1932 were reexamined in terms of state of the art fast switching transistors and diodes, and high energy density capacitors. Because of component improvements, the voltage multiplier, used without a transformer, now appears superior in weight to systems now in use for dc-dc conversion. An experimental 100-watt 1000-volt dc-dc converter operating at 100 kHz was built, with a component weight of about 1 kg/kW. Calculated and measured values of output voltage and efficiency agreed within experimental error.
Children's Understanding of the Relationship between Addition and Subtraction
ERIC Educational Resources Information Center
Gilmore, Camilla K.; Spelke, Elizabeth S.
2008-01-01
In learning mathematics, children must master fundamental logical relationships, including the inverse relationship between addition and subtraction. At the start of elementary school, children lack generalized understanding of this relationship in the context of exact arithmetic problems: they fail to judge, for example, that 12 + 9 - 9 yields…
Summation and subtraction using a modified autoshaping procedure in pigeons.
Ploog, Bertram O
2008-06-01
A modified autoshaping paradigm (significantly different from those previously reported in the summation literature) was employed to allow for the simultaneous assessment of stimulus summation and subtraction in pigeons. The response requirements and the probability of food delivery were adjusted such that towards the end of training 12 of 48 trials ended in food delivery, the same proportion as under testing. Stimuli (outlines of squares of three sizes and colors: A, B, and C) were used that could be presented separately or in any combination of two or three stimuli. Twelve of the pigeons (summation groups) were trained with either A, B, and C or with AB, BC, and CA, and tested with ABC. The remaining 12 pigeons (subtraction groups) received training with ABC but were tested with A, B, and C or with AB, BC, and CA. These groups were further subdivided according to whether stimulus elements were presented either in a concentric or dispersed manner. Summation did not occur; subtraction occurred in the two concentric groups. For interpretation of the results, configural theory, the Rescorla-Wagner model, and the composite-stimulus control model were considered. The results suggest different mechanisms responsible for summation and subtraction.
Structuring Numbers 1 to 20: Developing Facile Addition and Subtraction
ERIC Educational Resources Information Center
Ellemor-Collins, David; Wright, Robert
2009-01-01
The Numeracy Intervention Research Project (NIRP) aims to develop assessment and instructional tools for use with low-attaining 3rd- and 4th-graders. The NIRP approach to instruction in addition and subtraction in the range 1 to 20 is described. The approach is based on a notion of structuring numbers, which draws on the work of Freudenthal and…
Enriching Addition and Subtraction Fact Mastery through Games
ERIC Educational Resources Information Center
Bay-Williams, Jennifer M.; Kling, Gina
2014-01-01
The learning of "basic facts"--single-digit combinations for addition, subtraction, multiplication, and division--has long been a focus of elementary school mathematics. Many people remember completing endless worksheets, timed tests, and flash card drills as they attempted to "master" their basic facts as children. However,…
Addition and Subtraction by Students with Down Syndrome
ERIC Educational Resources Information Center
Herrera, Aurelia Noda; Bruno, Alicia; Gonzalez, Carina; Moreno, Lorenzo; Sanabria, Hilda
2011-01-01
We present a research report on addition and subtraction conducted with Down syndrome students between the ages of 12 and 31. We interviewed a group of students with Down syndrome who executed algorithms and solved problems using specific materials and paper and pencil. The results show that students with Down syndrome progress through the same…
"Abuelita" Epistemologies: Counteracting Subtractive Schools in American Education
ERIC Educational Resources Information Center
Gonzales, Sandra M.
2015-01-01
This autoethnographic inquiry examines the intersection of elder epistemology and subtractive education, exploring how one "abuelita" countered her granddaughter's divestment of Mexican-ness. I demonstrate how the grandmother used "abuelita" epistemologies to navigate this tension and resist the assimilative pressures felt…
A New Sky Subtraction Technique for Low Surface Brightness Data
NASA Astrophysics Data System (ADS)
Katkov, I. Y.; Chilingarian, I. V.
2011-07-01
We present a new approach to the sky subtraction for long-slit spectra that is suitable for low-surface brightness objects based on the controlled reconstruction of the night sky spectrum in the Fourier space using twilight or arc-line frames as references. It can be easily adopted for FLAMINGOS-type multi-slit data. Compared to existing sky subtraction algorithms, our technique is taking into account variations of the spectral line spread along the slit thus qualitatively improving the sky subtraction quality for extended targets. As an example, we show how the stellar metallicity and stellar velocity dispersion profiles in the outer disc of the spiral galaxy NGC5440 are affected by the sky subtraction quality. Our technique is used in the survey of early-type galaxies carried out at the Russian 6-m telescope, and it strongly increases the scientific potential of large amounts of long-slit data for nearby galaxies available in major data archives.
Cutaneous Force Feedback as a Sensory Subtraction Technique in Haptics.
Prattichizzo, D; Pacchierotti, C; Rosati, G
2012-01-01
A novel sensory substitution technique is presented. Kinesthetic and cutaneous force feedback are substituted by cutaneous feedback (CF) only, provided by two wearable devices able to apply forces to the index finger and the thumb, while holding a handle during a teleoperation task. The force pattern, fed back to the user while using the cutaneous devices, is similar, in terms of intensity and area of application, to the cutaneous force pattern applied to the finger pad while interacting with a haptic device providing both cutaneous and kinesthetic force feedback. The pattern generated using the cutaneous devices can be thought as a subtraction between the complete haptic feedback (HF) and the kinesthetic part of it. For this reason, we refer to this approach as sensory subtraction instead of sensory substitution. A needle insertion scenario is considered to validate the approach. The haptic device is connected to a virtual environment simulating a needle insertion task. Experiments show that the perception of inserting a needle using the cutaneous-only force feedback is nearly indistinguishable from the one felt by the user while using both cutaneous and kinesthetic feedback. As most of the sensory substitution approaches, the proposed sensory subtraction technique also has the advantage of not suffering from stability issues of teleoperation systems due, for instance, to communication delays. Moreover, experiments show that the sensory subtraction technique outperforms sensory substitution with more conventional visual feedback (VF).
Teaching Children about the Inverse Relation between Addition and Subtraction
ERIC Educational Resources Information Center
Nunes, Terezinha; Bryant, Peter; Hallett, Darcy; Bell, Daniel; Evans, Deborah
2009-01-01
Two intervention studies are described. Both were designed to study the effects of teaching children about the inverse relation between addition and subtraction. The interventions were successful with 8-year-old children in Study 1 and to a limited extent with 5-year-old children in Study 2. In Study 1 teaching children about inversion increased…
Quasi-optical overmoded waveguide frequency multiplier grid arrays
NASA Astrophysics Data System (ADS)
Rosenau, Steven Andrew
There is a growing need for compact, lightweight, inexpensive high power millimeter wave sources. Frequency multipliers can provide these sources by efficiently converting high power microwave signals to millimeter frequencies. Quasi-optical frequency multiplier grid arrays, comprised of hundreds to thousands of varactor devices and antennas on a single wafer, utilize spatial power combining to significantly increase power handling capability beyond that of a single device. In this dissertation work, theoretical and experimental investigations of frequency multiplier grid arrays have been conducted with a specific focus on overmoded waveguide systems. The principles of frequency multipliers and quasi-optical grid array power combining are presented. Simulation, design and experimental measurement techniques are described for both frequency tripler and doubler grid arrays. During this dissertation work, several quantum barrier varactor frequency tripler grid array systems and Schottky varactor frequency doubler grid array systems were designed, fabricated and tested. A frequency tripler grid array system, containing an innovative integrated output structure, achieved a multiplication efficiency of 3.4% and an output power of 148 mW. The two most efficient frequency doubler grid array systems achieved 11.7% multiplication efficiency and 0.41 W output power.
Cooking Skills Instruction with Severely Multiply Handicapped Adolescents.
ERIC Educational Resources Information Center
Horsfall, Debbie; Maggs, Alex
1986-01-01
Examination of the acquisition, maintenance, and generalization of three cooking skills by three multiply and severely handicapped blind adolescents revealed that a "whole task" approach was successful in teaching the subjects to boil an egg, grill cheese, and cook a TV dinner. These skills also generalized to other cooking products. (Author/CB)
Multiply-Impaired Blind Children: A National Problem.
ERIC Educational Resources Information Center
Graham, Milton D.
In 1966, a national survey reported on 8,887 multiply impaired (MI) blind children. About 56% were boys; 85% had been blind since before age 3, and half were totally blind. The principal causes of blindness were retrolental fibroplasia and congenital cataracts. Almost 63% had two or more additional disabilities (86.8% of those under age 6), such…
Training Social Skills to Severely Mentally Retarded Multiply Handicapped Adolescents.
ERIC Educational Resources Information Center
Matson, Johnny L.; And Others
1988-01-01
Three severely mentally retarded, multiply handicapped adolescents were treated in a classroom setting for social skill deficits. Treatment focused on increasing eye contact and strengthening on-task and in-seat behaviors. Results suggested that a combination of visual stimuli, operant, and social learning methods can be used to successfully…
Familiar Sports and Activities Adapted for Multiply Impaired Persons.
ERIC Educational Resources Information Center
Schilling, Mary Lou, Ed.
1984-01-01
Means of adapting some familiar and popular physical activities for multiply impaired persons are described. Games reviewed are dice baseball, one base baseball, in-house bowling, wheelchair bowling, ramp bowling, swing-ball bowling, table tennis, shuffleboard, beanbag bingo and tic-tac-toe, balloon basketball, circle football, and wheelchair…
Gilles de la Tourette Disease in Multiply Disabled Children.
ERIC Educational Resources Information Center
Kerbeshian, Jacob; And Others
1985-01-01
Giles de La Tourette disease (TD) is characterized by multiform changing vocal and motor tics with a wide range of accompanying behavioral symptoms. The range of tics and behavioral problems seen in TD is described along with a typcial case report in a multiply disabled child. Diagnostic criteria, and treatment recommendations are also given.…
Multiplying Is More than Math--It's Also Good Management
ERIC Educational Resources Information Center
Foster, Elise; Wiseman, Liz
2015-01-01
Studying more than 400 educational leaders, the authors propose a new model for leadership and management rooted in the belief that there is latent intelligence inside schools and educational organizations. Their findings suggest two dramatically different types of leaders, Multipliers and Diminishers. The five disciplines that distinguish…
A cascaded three-phase symmetrical multistage voltage multiplier
NASA Astrophysics Data System (ADS)
Iqbal, Shahid; Singh, G. K.; Besar, R.; Muhammad, G.
2006-10-01
A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM.
Improved channel multiplier for radiation-and-particle detectors
NASA Technical Reports Server (NTRS)
Schmidt, K. C.
1975-01-01
Multiplier is formed of glass and includes cylindrically-shaped main channel element having length-to-diameter ratio of 50 to 1. Element has open slot along its length. Attached to slot edges are two glass plates set at an angle to each other. Inside surfaces are coated with secondary electron emissive coating.
Fixed-Tuned Submillimeter Waveguide Multipliers Using MMIC Technology
NASA Technical Reports Server (NTRS)
Bruston, J.; Kim, M.; Martin, S. C.; Pease, A.; Smith, R. P.; Siegel, P. H.
1997-01-01
In preparation for the insturment ammouncement of opportunity for the Far Infrared and Submillimeter Space Telescope, and ESA/NASA space astrophysics observatory mission, local oscillator sources at high frequencies (1200 GHz) are being developed. As part of a multiplier chain beginning at 100 GHz we are developing single and multiple diode waveguide circuits up to 640 GHz.
Multiply-Constrained Semantic Search in the Remote Associates Test
ERIC Educational Resources Information Center
Smith, Kevin A.; Huber, David E.; Vul, Edward
2013-01-01
Many important problems require consideration of multiple constraints, such as choosing a job based on salary, location, and responsibilities. We used the Remote Associates Test to study how people solve such multiply-constrained problems by asking participants to make guesses as they came to mind. We evaluated how people generated these guesses…
Medium power voltage multipliers with a large number of stages
NASA Technical Reports Server (NTRS)
Harrigill, W. T.; Myers, I. T.
1978-01-01
Voltage multiplier techniques are extended at medium power levels to larger multiplication ratios. A series of dc-dc converters were built, with from 20 to 45 stages and with power levels up to 100 watts. Maximum output voltages were about 10,000 volts.
Multiplier methods for optimization problems with Lipschitzian derivatives
NASA Astrophysics Data System (ADS)
Izmailov, A. F.; Kurennoy, A. S.
2012-12-01
Optimization problems for which the objective function and the constraints have locally Lipschitzian derivatives but are not assumed to be twice differentiable are examined. For such problems, analyses of the local convergence and the convergence rate of the multiplier (or the augmented Lagrangian) method and the linearly constraint Lagrangian method are given.
Problems with Accurate Atomic Lfetime Measurements of Multiply Charged Ions
Trabert, E
2009-02-19
A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest to remain cautious about the systematic errors of experimental techniques.
Functional Sign Training for the Severely Multiply Handicapped.
ERIC Educational Resources Information Center
Waldo, Lois; And Others
A training manual for teaching functional sign training to the severely multiply handicapped was developed using the Signing Exact English (SEE) system. The program, which was adapted from the Functional Speech and Language Training Program, is designed for persons who lack refined motor, speech, and language skills. Procedures are outlined to use…
Self-mixing differential vibrometer based on electronic channel subtraction.
Donati, Silvano; Norgia, Michele; Giuliani, Guido
2006-10-01
An instrument for noncontact measurement of differential vibrations is developed, based on the self-mixing interferometer. As no reference arm is available in the self-mixing configuration, the differential mode is obtained by electronic subtraction of signals from two (nominally equal) vibrometer channels, taking advantage that channels are servo stabilized and thus insensitive to speckle and other sources of amplitude fluctuation. We show that electronic subtraction is nearly as effective as field superposition. Common-mode suppression is 25-30 dB, the dynamic range (amplitude) is in excess of 100 microm, and the minimum measurable (differential) amplitude is 20 nm on a B = 10 kHz bandwidth. The instrument has been used to measure vibrations of two metal samples kept in contact, revealing the hysteresis cycle in the microslip and gross-slip regimes, which are of interest in the study of friction induced vibration damping of gas turbine blades for aircraft applications. PMID:16983412
Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients.
Hyun, Seung-Jae; Kim, Yongjung J; Rhim, Seung-Chul
2013-11-16
In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided.
Removing Cardiac Artefacts in Magnetoencephalography with Resampled Moving Average Subtraction
Ahlfors, Seppo P.; Hinrichs, Hermann
2016-01-01
Magnetoencephalography (MEG) signals are commonly contaminated by cardiac artefacts (CAs). Principle component analysis and independent component analysis have been widely used for removing CAs, but they typically require a complex procedure for the identification of CA-related components. We propose a simple and efficient method, resampled moving average subtraction (RMAS), to remove CAs from MEG data. Based on an electrocardiogram (ECG) channel, a template for each cardiac cycle was estimated by a weighted average of epochs of MEG data over consecutive cardiac cycles, combined with a resampling technique for accurate alignment of the time waveforms. The template was subtracted from the corresponding epoch of the MEG data. The resampling reduced distortions due to asynchrony between the cardiac cycle and the MEG sampling times. The RMAS method successfully suppressed CAs while preserving both event-related responses and high-frequency (>45 Hz) components in the MEG data. PMID:27503196
ZAP - enhanced PCA sky subtraction for integral field spectroscopy
NASA Astrophysics Data System (ADS)
Soto, Kurt T.; Lilly, Simon J.; Bacon, Roland; Richard, Johan; Conseil, Simon
2016-05-01
We introduce Zurich Atmosphere Purge (ZAP), an approach to sky subtraction based on principal component analysis (PCA) that we have developed for the Multi Unit Spectrographic Explorer (MUSE) integral field spectrograph. ZAP employs filtering and data segmentation to enhance the inherent capabilities of PCA for sky subtraction. Extensive testing shows that ZAP reduces sky emission residuals while robustly preserving the flux and line shapes of astronomical sources. The method works in a variety of observational situations from sparse fields with a low density of sources to filled fields in which the target source fills the field of view. With the inclusion of both of these situations, the method is generally applicable to many different science cases and should also be useful for other instrumentation. ZAP is available for download at http://muse-vlt.eu/science/tools.
Robust Background Subtraction with Foreground Validation for Urban Traffic Video
Cheung, S S; Kamath, C
2004-01-15
Identifying moving objects in a video sequence is a fundamental and critical task in many computer-vision applications. Background subtraction techniques are commonly used to separate foreground moving objects from the background. Most background subtraction techniques assume a single rate of adaptation, which is inadequate for complex scenes such as a traffic intersection where objects are moving at different and varying speeds. In this paper, we propose a foreground validation algorithm that first builds a foreground mask using a slow-adapting Kalman filter, and then validates individual foreground pixels by a simple moving object model, built using both the foreground and background statistics as well as the frame difference. Ground-truth experiments with urban traffic sequences show that our proposed algorithm significantly improves upon results using only Kalman filter or frame-differencing, and outperforms other techniques based on mixture of Gaussians, median filter, and approximated media filter.
Subtraction of Positive and Negative Numbers: The Difference and Completion Approaches with Chips
ERIC Educational Resources Information Center
Flores, Alfinio
2008-01-01
Diverse contexts such as "take away," comparison," and "completion" give rise to subtraction problems. The take-away interpretation of subtraction has been explored using two-colored chips to help students understand addition and subtraction of integers. This article illustrates how the difference and completion (or missing addend) interpretations…
ERIC Educational Resources Information Center
Canobi, Katherine H.; Bethune, Narelle E.
2008-01-01
Three studies addressed children's arithmetic. First, 50 3- to 5-year-olds judged physical demonstrations of addition, subtraction and inversion, with and without number words. Second, 20 3- to 4-year-olds made equivalence judgments of additions and subtractions. Third, 60 4- to 6-year-olds solved addition, subtraction and inversion problems that…
Digital subtraction angiography in pediatric cerebrovascular occlusive disease
Faerber, E.N.; Griska, L.A.B.; Swartz, J.D.; Capitanio, M.A.; Popky, G.L.
1984-08-01
While conventional angiography has been used to demonstrate cerebrovascular occlusive disease in the past, digital subtraction angiography (DSA) is capable of showing progressive vascular involvement with ease, simplicity, and extremely low morbidity, making it particularly well suited for children and outpatients either alone or coordinated with computed tomography. The authors discuss the usefulness and advantages of DSA as demonstrated in 7 infants and children with hemiplegia, 4 of whom had sickle-cell disease.
Subtractive Renormalization Group Invariance: Pionless EFT at NLO
Timoteo, Varese S.; Szpigel, Sergio; Duraes, Francisco O.
2010-11-12
We show some results concerning the renormalization group (RG) invariance of the nucleon-nucleon (NN) interaction in pionless effective field theory at next-to-leading order (NLO), using a non-relativistic Callan-Symanzik equation (NRCS) for the driving term of the Lippmann-Schwinger (LS) equation with three recursive subtractions. The phase-shifts obtained for the RG evolved potential are same as those for the original potential, apart from relative differences of order 10{sup -15}.
ROBUST TECHNIQUES FOR BACKGROUND SUBTRACTION IN URBAN TRAFFIC VIDEO
Kamath, C; Cheung, S S
2003-10-28
Identifying moving objects from a video sequence is a fundamental and critical task in many computer-vision applications. A common approach is to perform background subtraction, which identifies moving objects from the portion of a video frame that differs significantly from a background model. There are many challenges in developing a good background subtraction algorithm. First, it must be robust against changes in illumination. Second, it should avoid detecting non-stationary background objects such as swinging leaves, rain, snow, and shadow cast by moving objects. Finally, its internal background model should react quickly to changes in background such as starting and stopping of vehicles. In this paper, we compare various background subtraction algorithms for detecting moving vehicles and pedestrians in urban traffic video sequences. We consider approaches varying from simple techniques such as frame differencing and adaptive median filtering, to more sophisticated probabilistic modeling techniques. While complicated techniques often produce superior performance, our experiments show that simple techniques such as adaptive median filtering can produce good results with much lower computational complexity.
A generalized algorithm to design finite field normal basis multipliers
NASA Technical Reports Server (NTRS)
Wang, C. C.
1986-01-01
Finite field arithmetic logic is central in the implementation of some error-correcting coders and some cryptographic devices. There is a need for good multiplication algorithms which can be easily realized. Massey and Omura recently developed a new multiplication algorithm for finite fields based on a normal basis representation. Using the normal basis representation, the design of the finite field multiplier is simple and regular. The fundamental design of the Massey-Omura multiplier is based on a design of a product function. In this article, a generalized algorithm to locate a normal basis in a field is first presented. Using this normal basis, an algorithm to construct the product function is then developed. This design does not depend on particular characteristics of the generator polynomial of the field.
Mass-dependent channel electron multiplier operation. [for ion detection
NASA Technical Reports Server (NTRS)
Fields, S. A.; Burch, J. L.; Oran, W. A.
1977-01-01
The absolute counting efficiency and pulse height distributions of a continuous-channel electron multiplier used in the detection of hydrogen, argon and xenon ions are assessed. The assessment technique, which involves the post-acceleration of 8-eV ion beams to energies from 100 to 4000 eV, provides information on counting efficiency versus post-acceleration voltage characteristics over a wide range of ion mass. The charge pulse height distributions for H2 (+), A (+) and Xe (+) were measured by operating the experimental apparatus in a marginally gain-saturated mode. It was found that gain saturation occurs at lower channel multiplier operating voltages for light ions such as H2 (+) than for the heavier ions A (+) and Xe (+), suggesting that the technique may be used to discriminate between these two classes of ions in electrostatic analyzers.
Multiply-constrained semantic search in the Remote Associates Test.
Smith, Kevin A; Huber, David E; Vul, Edward
2013-07-01
Many important problems require consideration of multiple constraints, such as choosing a job based on salary, location, and responsibilities. We used the Remote Associates Test to study how people solve such multiply-constrained problems by asking participants to make guesses as they came to mind. We evaluated how people generated these guesses by using Latent Semantic Analysis to measure the similarity between the guesses, cues, and answers. We found that people use two systematic strategies to solve multiply-constrained problems: (a) people produce guesses primarily on the basis of just one of the three cues at a time; and (b) people adopt a local search strategy--they make new guesses based in part on their previous guesses. These results inform how people combine constraints to search through and retrieve semantic information from memory.
Real Km-synthesis via generalized Popov multipliers
NASA Technical Reports Server (NTRS)
Chiang, R. Y.; Safonov, M. G.
1992-01-01
The authors refine their H-infinity control designs presented at the 1990 and 1991 American Control Conference by introducing a new real Km-synthesis technique involving the use of generalized Popov multipliers. This multiplier technique substantially reduces, and in some cases may even eliminate altogether, the conservativeness associated with traditional Km-synthesis solutions in which all uncertainties are treated as complex, even when they arise from real parameters such as the masses and spring constants in the benchmark problem. The design results demonstrate how this approach permits a very precise analysis of the intrinsic tradeoffs between robustness, performance, and control energy requirements. Also included is an open-loop H-infinity prefilter design that makes it possible to address the command response shaping issue. The design concept has been applied to the benchmark problem no. 4 and successfully removes the initial undesired transient and cuts down the percent overshoot.
Temporal subtraction contrast-enhanced dedicated breast CT.
Gazi, Peymon M; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M
2016-09-01
The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE). The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0-16%), NCC (0-6%), NMI (0-13%) and TRE (0-34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was
Temporal subtraction contrast-enhanced dedicated breast CT
NASA Astrophysics Data System (ADS)
Gazi, Peymon M.; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M.
2016-09-01
The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE). The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0-16%), NCC (0-6%), NMI (0-13%) and TRE (0-34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was
Temporal subtraction contrast-enhanced dedicated breast CT
NASA Astrophysics Data System (ADS)
Gazi, Peymon M.; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M.
2016-09-01
The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE). The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0–16%), NCC (0–6%), NMI (0–13%) and TRE (0–34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was
NASA Astrophysics Data System (ADS)
Callebaut, Nele; Gubser, Steven S.; Samberg, Andreas; Toldo, Chiara
2015-11-01
We study segmented strings in flat space and in AdS 3. In flat space, these well known classical motions describe strings which at any instant of time are piecewise linear. In AdS 3, the worldsheet is composed of faces each of which is a region bounded by null geodesics in an AdS 2 subspace of AdS 3. The time evolution can be described by specifying the null geodesic motion of kinks in the string at which two segments are joined. The outcome of collisions of kinks on the worldsheet can be worked out essentially using considerations of causality. We study several examples of closed segmented strings in AdS 3 and find an unexpected quasi-periodic behavior. We also work out a WKB analysis of quantum states of yo-yo strings in AdS 5 and find a logarithmic term reminiscent of the logarithmic twist of string states on the leading Regge trajectory.
NASA Astrophysics Data System (ADS)
Costa, Miguel S.; Greenspan, Lauren; Oliveira, Miguel; Penedones, João; Santos, Jorge E.
2016-06-01
We consider solutions in Einstein-Maxwell theory with a negative cosmological constant that asymptote to global AdS 4 with conformal boundary {S}2× {{{R}}}t. At the sphere at infinity we turn on a space-dependent electrostatic potential, which does not destroy the asymptotic AdS behaviour. For simplicity we focus on the case of a dipolar electrostatic potential. We find two new geometries: (i) an AdS soliton that includes the full backreaction of the electric field on the AdS geometry; (ii) a polarised neutral black hole that is deformed by the electric field, accumulating opposite charges in each hemisphere. For both geometries we study boundary data such as the charge density and the stress tensor. For the black hole we also study the horizon charge density and area, and further verify a Smarr formula. Then we consider this system at finite temperature and compute the Gibbs free energy for both AdS soliton and black hole phases. The corresponding phase diagram generalizes the Hawking-Page phase transition. The AdS soliton dominates the low temperature phase and the black hole the high temperature phase, with a critical temperature that decreases as the external electric field increases. Finally, we consider the simple case of a free charged scalar field on {S}2× {{{R}}}t with conformal coupling. For a field in the SU(N ) adjoint representation we compare the phase diagram with the above gravitational system.
The gas electron multiplier (GEM): Operating principles and applications
NASA Astrophysics Data System (ADS)
Sauli, Fabio
2016-01-01
Introduced by the author in 1997, The Gas Electron Multiplier (GEM) constitutes a powerful addition to the family of fast radiation detectors; originally developed for particle physics experiments, the device and has spawned a large number of developments and applications; a web search yields more than 400 articles on the subject. This note is an attempt to summarize the status of the design, developments and applications of the new detector.
Cleaning and activation of beryllium-copper electron multiplier dynodes.
NASA Technical Reports Server (NTRS)
Pongratz, M. B.
1972-01-01
Description of a cleaning and activation procedure followed in preparing beryllium-copper dynodes for electron multipliers used in sounding-rocket experiments to detect auroral electrons. The initial degreasing step involved a 5-min bath in trichloroethylene in an ultrasonic cleaner. This was followed by an ultrasonic rinse in methanol and by a two-step acid pickling treatment to remove the oxides. Additional rinsing in water and methanol was followed by activation in a stainless-steel RF induction oven.
L^p-Fourier multipliers with bounded powers
NASA Astrophysics Data System (ADS)
Lebedev, V. V.; Olevskii, A. M.
2006-06-01
We consider the space M_p(\\mathbb R^d) of L^p-Fourier multipliers and give a detailed proof of the following result announced by the authors in [10]: if \\varphi\\colon\\mathbbR^d\\to \\lbrack0, 2\\pi\\lbrack is a measurable function and \\Vert e^{in\\varphi}\\Vert _{M_p}=O(1), n\\in\\mathbb Z, for some p\
Ramos Alvarenga, René F; Friesen, J Brent; Nikolić, Dejan; Simmler, Charlotte; Napolitano, José G; van Breemen, Richard; Lankin, David C; McAlpine, James B; Pauli, Guido F; Chen, Shao-Nong
2014-12-26
This study introduces a flexible and compound targeted approach to Deplete and Enrich Select Ingredients to Generate Normalized Extract Resources, generating DESIGNER extracts, by means of chemical subtraction or augmentation of metabolites. Targeting metabolites based on their liquid-liquid partition coefficients (K values), K targeting uses countercurrent separation methodology to remove single or multiple compounds from a chemically complex mixture, according to the following equation: DESIGNER extract = total extract ± target compound(s). Expanding the scope of the recently reported depletion of extracts by immunoaffinity or solid phase liquid chromatography, the present approach allows a more flexible, single- or multi-targeted removal of constituents from complex extracts such as botanicals. Chemical subtraction enables both chemical and biological characterization, including detection of synergism/antagonism by both the subtracted targets and the remaining metabolite mixture, as well as definition of the residual complexity of all fractions. The feasibility of the DESIGNER concept is shown by K-targeted subtraction of four bioactive prenylated phenols, isoxanthohumol (1), 8-prenylnaringenin (2), 6-prenylnaringenin (3), and xanthohumol (4), from a standardized hops (Humulus lupulus L.) extract using specific solvent systems. Conversely, adding K-targeted isolates allows enrichment of the original extract and hence provides an augmented DESIGNER material. Multiple countercurrent separation steps were used to purify each of the four compounds, and four DESIGNER extracts with varying depletions were prepared. The DESIGNER approach innovates the characterization of chemically complex extracts through integration of enabling technologies such as countercurrent separation, K-by-bioactivity, the residual complexity concepts, as well as quantitative analysis by (1)H NMR, LC-MS, and HiFSA-based NMR fingerprinting. PMID:25437744
Nonlinear optical response of multiply ionized noble-gas atoms
NASA Astrophysics Data System (ADS)
Tarazkar(1, 3), Maryam; Romanov(2, 3), Dmitri; Levis(1, 3), Robert
2016-05-01
Calculation of dynamic polarizabilities and hyperpolarizabilities of ionized species using ab initio methods presents computational and conceptual difficulties, as these ionized species often have open-shell electronic system. We use multi-configurational self-consistent field (MCSCF) method with extended basis sets for calculating dynamic polarizability and second-order hyperpolarizabilities of atomic noble gases and their multiply charged cations in non-resonant regime. The calculations were performed at wavelengths ranging from about 100 nm to the red of the first multi-photon resonance all the way toward the static regime. The results were benchmarked to those of CCSD calculations for ions of even-number charge. The second-order hyperpolarizability coefficients were found to decrease when the electrons are progressively removed from the system. At higher ionization states, these coefficients become less dispersive as a function of wavelength. The values and even the signs of the γ (2) coefficients were found to depend on the spin of the ionic quantum state. Thus, for Ne+3 and Ne+4, in low-spin states (2 Pu, and 1 Sg, respectively) the sign of γ (2) is positive, whereas in high-spin states (4 Su, and 3 Pg) the sign is negative. The calculated hyperpolarizabilities of multiply ionized atoms relate to experiments on very bright high-order harmonic generation in multiply ionized plasmas.
A Voltage Multiplier for the nEDM Experiment
NASA Astrophysics Data System (ADS)
Bouman, Nathaniel; Stanislaus, Shirantha; Valpo nEDM Team
2015-10-01
The nEDM experiment at Oak Ridge National Laboratory aims to search for the electric dipole moment of the neutron (nEDM) at the 10-28 level. The experiment is currently at the research and development phase. One of the variables proportional to the sensitivity of the measurement is the strength of the electric field in the measurement cell where the effect of an nEDM is to be generated. The design of the experiment calls for an electric field of 75 kV/cm in this cell. A unique voltage multiplier involving a variable capacitor has been proposed to achieve this large required electric field. Electrostatic calculations using two independent software packages, COMSOL and Field Precision, were carried out to study the feasibility of the proposed voltage multiplier. A prototype of the electrodes and the voltage multiplier whose size was 25% of full size was also built to verify the predictions of the electrostatic calculations. Results of the tests with the prototype and the electrostatic calculations, will be presented.
Boretto, J; Longhi, S; Navarro, J M; Selmi, B; Sire, J; Canard, B
2001-05-01
We describe a gene system allowing the facile production of multiply substituted reverse transcriptases (RTs), the enzymatic characterization of these purified RTs, and the study of these mutations in the defined genetic background of the macrophagetropic, non-laboratory-adapted human immunodeficiency virus type 1 (HIV-1) AD8 strain. Thirteen unique silent restriction sites were introduced in the pol gene encoding HIV-1 RT, allowing easy introduction of mutations. To simplify genetic manipulation and generate p66/p51 heterodimers in Escherichia coli, a gene construct of the viral protease alone was optimized for expression from a separate vector carrying a p15A origin of replication. Active-site titration experiments using pre-steady-state kinetics showed that our system yields a higher proportion of active enzyme than that obtained by alternate methods. To facilitate phenotype/genotype correlations, the modified RT gene was designed to be easily reintroduced into a recombinant proviral AD8 HIV-1 DNA. Infectious viruses made from this vector were undistinguishable from wild-type AD8 HIV-1, an isolate able to infect peripheral blood mononuclear cells and macrophages. Thus, the pol gene can tolerate many silent mutations in the polymerase domain without affecting the functionality of the HIV-1 genome. The system was validated biochemically and virologically using the V75T substitution associated with stavudine resistance.
Economic Multipliers: Can a Rural Community Use Them? Coping with Growth.
ERIC Educational Resources Information Center
Lewis, Eugene; And Others
Presenting concepts generally applicable only to small rural regions or to local economies, this publication explains multipliers, shows how they are used in calculating impacts, and provides some criteria for determining whether a given multiplier can be used in a specific situation. Following a discussion of aggregate multipliers, which lump…
Modeling Sustained Educational Change with Panel Data: The Case for Dynamic Multiplier Analysis.
ERIC Educational Resources Information Center
Kaplan, David
2002-01-01
Considers the problem of modeling sustained educational change through the use of dynamic multipliers applied to panel data and attempts to develop and advocate dynamic multiplier analysis for educational research. Presents three examples to illustrate the approach and closes with a discussion of the implications of dynamic multiplier analysis for…
Children's use of addition to solve two-digit subtraction problems.
Peters, Greet; De Smedt, Bert; Torbeyns, Joke; Ghesquière, Pol; Verschaffel, Lieven
2013-11-01
Subtraction problems of the type M - S = ? can be solved with various mental calculation strategies. We investigated fourth- to sixth-graders' use of the subtraction by addition strategy, first by fitting regression models to the reaction times of 32 two-digit subtractions. These models represented three different strategy use patterns: the use of direct subtraction, subtraction by addition, and switching between the two strategies based on the magnitude of the subtrahend. Additionally, we compared performance on problems presented in two presentation formats, i.e., a subtraction format (81 - 37 = .) and an addition format (37 + . = 81). Both methods converged to the conclusion that children of all three grades switched between direct subtraction and subtraction by addition based on the combination of two features of the subtrahend: If the subtrahend was smaller than the difference, direct subtraction was the dominant strategy; if the subtrahend was larger than the difference, subtraction by addition was mainly used. However, this performance pattern was only observed when the numerical distance between subtrahend and difference was large. These findings indicate that theoretical models of children's strategy choices in subtraction should include the nature of the subtrahend as an important factor in strategy selection. PMID:24094280
Extraction versus non-extraction: evaluation by digital subtraction radiography.
Akyalçin, Sercan; Hazar, Serpil; Güneri, Pelin; Gögüs, Selin; Erdinç, Aslihan Mediha Ertan
2007-12-01
The aim of this study was to investigate the facial profile changes of patients treated with and without extractions of four first premolars using novel computer-based digital subtraction software. The pre- and post-treatment radiographic image pairs of 25 extraction (13 girls and 12 boys, mean age = 12.64 +/- 1.82 years) and 24 non-extraction (12 girls and 12 boys, mean age = 12.48 +/- 1.66 years) Class I patients were subtracted by the software. Student's t-tests were used to determine whether the subtraction values for the linear measurements of radiographic differences registered at various anatomical landmark parameters were statistically different between the groups. To further determine whether any variables related to upper and lower lip changes, regression analyses were performed. The main soft tissue differences between the groups were established at labrale superior, labrale inferior, and sulcus inferior points, with extraction patients showing significantly more retruded upper and lower lips. However, the mean differences between the groups did not exceed 1 mm for these variables. Changes at labrale superior and labrale inferior were associated with sagittal movement of the maxillary (r = 0.549) and mandibular (r = 0.630) incisor midpoints. Changes at sulcus inferior were associated with both sagittal and vertical displacement of mandibular incision point (r = 0.676). Some dentofacial alterations were found but in view of the differences between the groups pretreatment, the inter-group differences reflect different treatment intent rather than differences arising from the extraction and non-extraction modalities.
Skycorr: A general tool for spectroscopic sky subtraction
NASA Astrophysics Data System (ADS)
Noll, S.; Kausch, W.; Kimeswenger, S.; Barden, M.; Jones, A. M.; Modigliani, A.; Szyszka, C.; Taylor, J.
2014-07-01
Context. Airglow emission lines, which dominate the optical-to-near-infrared sky radiation, show strong, line-dependent variability on time scales from minutes to decades. Therefore, the subtraction of the sky background in the affected wavelength regime becomes a problem if plain-sky spectra have to be taken at a different time from the astronomical data. Aims: A solution of this problem is the physically motivated scaling of the airglow lines in the plain-sky data to fit the sky lines in the object spectrum. We have developed a corresponding instrument-independent approach based on one-dimensional spectra. Methods: Our code skycorr separates sky lines and sky/object continuum by an iterative approach involving a line finder and airglow line data. The sky lines, which mainly belong to OH and O2 bands, are grouped according to their expected variability. The line groups in the sky data are then scaled to fit the sky in the science data. Required pixel-specific weights for overlapping groups are taken from a comprehensive airglow model. Deviations in the wavelength calibration are corrected for by fitting Chebyshev polynomials and rebinning via asymmetric damped sinc kernels. The scaled sky lines and the sky continuum are subtracted separately. Results: ESO-VLT X-shooter data covering 2.5 h with a good time resolution were selected to illustrate the performance. Data taken six nights and about one year before were also used as reference sky data. The variation of the sky-subtraction quality as a function of time difference between the object and sky data depends on changes in the airglow intensity, atmospheric transparency, and instrument calibration. Except for short time intervals of a few minutes, the sky line residuals were between 2.1 and 5.5 times weaker than for sky subtraction without fitting. Additional tests showed that skycorr performs consistently better than the method of Davies (2007, MNRAS, 375, 1099) developed for ESO-VLT SINFONI data.
Addition and subtraction by students with Down syndrome
NASA Astrophysics Data System (ADS)
Noda Herrera, Aurelia; Bruno, Alicia; González, Carina; Moreno, Lorenzo; Sanabria, Hilda
2011-01-01
We present a research report on addition and subtraction conducted with Down syndrome students between the ages of 12 and 31. We interviewed a group of students with Down syndrome who executed algorithms and solved problems using specific materials and paper and pencil. The results show that students with Down syndrome progress through the same procedural levels as those without disabilities though they have difficulties in reaching the most abstract level (numerical facts). The use of fingers or concrete representations (balls) appears as a fundamental process among these students. As for errors, these vary widely depending on the students, and can be attributed mostly to an incomplete knowledge of the decimal number system.
[Ziedses des Plantes: inventor of planigraphy and subtraction].
van Gijn, Jan; Gijselhart, Joost P
2011-01-01
Bernard George Ziedses des Plantes (1902-1993) trained in Utrecht, the Netherlands, as specialist in nervous diseases, but his lifelong passion was to improve X-ray imaging of living tissues. In the 1930s he not only built the first machine for planigraphy, in which the X-ray tube and the film moved together around the plane of interest, but he also designed the subtraction method to improve images after injection of contrast agents. Eventually a full-time radiologist, he also developed the 'somersault' technique of ventriculography and pioneered isotope scintigraphy.
Peripheral NN scattering from subtractive renormalization of chiral interactions
Batista, E. F.; Szpigel, S.; Timóteo, V. S.
2014-11-11
We apply five subtractions in the Lippman-Schwinger (LS) equation in order to perform a non-perturbative renormalization of chiral N3LO nucleon-nucleon interactions. Here we compute the phase shifts for the uncoupled peripheral waves at renormalization scales between 0.1 fm{sup −1} and 1 fm{sup −1}. In this range, the results are scale invariant and provide an overall good agreement with the Nijmegen partial wave analysis up to at least E{sub lab} = 150 MeV, with a cutoff at Λ = 30 fm{sup −1}.
Quantitative Digital Subtraction Angiography in Pediatric Moyamoya Disease
2015-01-01
Moyamoya disease is a unique cerebrovascular disorder characterized by idiopathic progressive stenosis at the terminal portion of the internal carotid artery (ICA) and fine vascular network. The aim of this review is to present the clinical application of quantitative digital subtraction angiography (QDSA) in pediatric moyamoya disease. Using conventional angiographic data and postprocessing software, QDSA provides time-contrast intensity curves and then displays the peak time (Tmax) and area under the curve (AUC). These parameters of QDSA can be used as surrogate markers for the hemodynamic evaluation of disease severity and quantification of postoperative neovascularization in moyamoya disease. PMID:26180611
Walking boosts your performance in making additions and subtractions
Anelli, Filomena; Lugli, Luisa; Baroni, Giulia; Borghi, Anna M.; Nicoletti, Roberto
2014-01-01
Previous research demonstrates that the processing of spatial information and numerical magnitude are strictly interwoven. Recent studies also provide converging evidence that number processing is influenced by body movements. In the present study we further investigate this issue by focusing on whether and how motions experienced with the whole body can influence arithmetical calculations. We asked participants to make additions or subtractions while experiencing leftward and rightward motions. Data revealed the emergence of a congruency effect between the orientation inferred by the type of arithmetical calculations and the type of motions experienced along an horizontal axis. PMID:25566137
Itai, Yoshinori; Kim, Hyoungseop; Ishikawa, Seiji; Katsuragawa, Shigehiko; Doi, Kunio
2010-02-01
A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can be used for enhancing interval changes (such as formation of new lesions and changes in existing abnormalities) on medical images by removing most of the normal structures. However, subtraction artifacts are commonly included in temporal subtraction images obtained from thoracic computed tomography and thus tend to reduce its effectiveness in the detection of pulmonary nodules. In this study, we developed a new method for substantially removing the artifacts on temporal subtraction images of lungs obtained from multiple-detector computed tomography (MDCT) by using a voxel-matching technique. Our new method was examined on 20 clinical cases with MDCT images. With this technique, the voxel value in a warped (or nonwarped) previous image is replaced by a voxel value within a kernel, such as a small cube centered at a given location, which would be closest (identical or nearly equal) to the voxel value in the corresponding location in the current image. With the voxel-matching technique, the correspondence not only between the structures but also between the voxel values in the current and the previous images is determined. To evaluate the usefulness of the voxel-matching technique for removal of subtraction artifacts, the magnitude of artifacts remaining in the temporal subtraction images was examined by use of the full width at half maximum and the sum of a histogram of voxel values, which may indicate the average contrast and the total amount, respectively, of subtraction artifacts. With our new method, subtraction artifacts due to normal structures such as blood vessels were substantially removed on temporal subtraction images. This computerized method can enhance lung nodules on chest MDCT images without disturbing misregistration artifacts.
Monolithic millimeter-wave diode grid frequency multiplier arrays
NASA Technical Reports Server (NTRS)
Liu, Hong-Xia L.; Qin, X.-H.; Sjogren, L. B.; Wu, W.; Chung, E.; Domier, C. W.; Luhmann, N. C., Jr.
1992-01-01
Monolithic diode frequency multiplier arrays, including barrier-N-N(+) (BNN) doubler, multi-quantum-barrier-varactor (MQBV) tripler, Schottky-quantum-barrier-varactor (SQBV) tripler, and resonant-tunneling-diode (RTD) tripler arrays, have been successfully fabricated with yields between 85 and 99 percent. Frequency doubling and/or tripling have been observed for all the arrays. Output powers of 2.4-2.6 W (eta = 10-18 percent) at 66 GHz with the BNN doubler and 3.8-10 W (eta = 1.7-4 percent) at 99 GHz with the SQBV tripler have been achieved.
Arc lamp power supply using a voltage multiplier
NASA Technical Reports Server (NTRS)
Leighty, Bradley D.
1988-01-01
A power supply is provided for an arc discharge lamp which includes a relatively low voltage high current power supply section and a high voltage starter circuit. The low voltage section includes a transformer, rectifier, variable resistor and a bank of capacitors, while the starter circuit comprises several diodes and capacitors connected as a Cockcroft-Walton multiplier. The starting circuit is effectively bypassed when the lamp arc is established and serves to automatically provide a high starting voltage to re-strike the lamp arc if the arc is extinguished by a power interruption.
Multiply-agile encryption in high speed communication networks
Pierson, L.G.; Witzke, E.L.
1997-05-01
Different applications have different security requirements for data privacy, data integrity, and authentication. Encryption is one technique that addresses these requirements. Encryption hardware, designed for use in high-speed communications networks, can satisfy a wide variety of security requirements if that hardware is key-agile, robustness-agile and algorithm-agile. Hence, multiply-agile encryption provides enhanced solutions to the secrecy, interoperability and quality of service issues in high-speed networks. This paper defines these three types of agile encryption. Next, implementation issues are discussed. While single-algorithm, key-agile encryptors exist, robustness-agile and algorithm-agile encryptors are still research topics.
Frequency multiplied harmonic gyrotron-traveling-wave-tube amplifier
Choi, J.J.; Ganguly, A.K.; Armstrong, C.M. )
1994-06-01
Numerical simulations of a [ital W]-band two-stage tapered, frequency multiplied gyrotron- traveling-wave-tube amplifier are reported. Unlike conventional harmonic gyrodevices, a drive signal at the fundamental harmonic frequency is injected in the first stage for beam modulation, and amplified output radiation is extracted from the third harmonic cyclotron resonance interaction. Numerical results show that broadband millimeter wave radiation is obtained with an efficiency of 10%--15%, a gain of [similar to]30 dB, and an instantaneous bandwidth of [similar to]10% at a center frequency of 95 GHz for [Delta][ital v][sub [ital z
Convergence of a Substructuring Method with LaGrange Multipliers
NASA Technical Reports Server (NTRS)
Mandel, Jan; Tezaur, Radek
1996-01-01
We analyze the convergence of a substructuring iterative method with Lagrange multipliers, proposed recently by Farhat and Roux. The method decomposes finite element discretization of an elliptic boundary value problem into Neumann problems on the subdomains and a coarse problem for the subdomain nullspace components. For linear conforming elements and preconditioning by the Dirichlet problems on the subdomains, we prove the asymptotic bound on the condition number C(1 + log(H/h))(sup gamma), gamma = 2 or 3, where h is the characteristic element size and H is the subdomain size.
The research about the quick algorithm of subtracting the DTM
NASA Astrophysics Data System (ADS)
Chian, Tao; Li, Yan; Geng, Juan
2007-06-01
There is some relationship between the Digital Surface Model (DSM) and the Digital Terrain Model (DTM). The contents they express are relative: DSM expresses the height we focus on about the surface of the ground, including the terrain and the objects on it, and DTM only gives the height of the terrain excluding the objects above it. DSM have the information of DTM, therefore it provides us a chance to subtract the DTM from the DSM. Mathematical morphology is a new method applied to Imagery processing and pattern recognition fields. It provides an effective method of subtracting DTM from DSM. But in practical application, the original calculations of these two are in low efficiency. Especially when it comes to a large template or huge block data, the computation speed can be a very headache question. This paper is studying the implementing process of the Open and the Close operators, especially the Erode and the Dilate calculations. Then we have developed two kinds of quick algorithms, which are aim to avoid the repeated calculation, and to enhance the efficiency sharply. The step of the two operations also should be refined, while the disposals are different from each other depending on the distinct configuration of these two kinds of algorithms.
Fast Image Subtraction Using Multi-cores and GPUs
NASA Astrophysics Data System (ADS)
Hartung, Steven; Shukla, H.
2013-01-01
Many important image processing techniques in astronomy require a massive number of computations per pixel. Among them is an image differencing technique known as Optimal Image Subtraction (OIS), which is very useful for detecting and characterizing transient phenomena. Like many image processing routines, OIS computations increase proportionally with the number of pixels being processed, and the number of pixels in need of processing is increasing rapidly. Utilizing many-core graphical processing unit (GPU) technology in a hybrid conjunction with multi-core CPU and computer clustering technologies, this work presents a new astronomy image processing pipeline architecture. The chosen OIS implementation focuses on the 2nd order spatially-varying kernel with the Dirac delta function basis, a powerful image differencing method that has seen limited deployment in part because of the heavy computational burden. This tool can process standard image calibration and OIS differencing in a fashion that is scalable with the increasing data volume. It employs several parallel processing technologies in a hierarchical fashion in order to best utilize each of their strengths. The Linux/Unix based application can operate on a single computer, or on an MPI configured cluster, with or without GPU hardware. With GPU hardware available, even low-cost commercial video cards, the OIS convolution and subtraction times for large images can be accelerated by up to three orders of magnitude.
Acquisition-related motion compensation for digital subtraction angiography.
Ionasec, Razvan Ioan; Heigl, Benno; Hornegger, Joachim
2009-06-01
Subtraction methods in angiography are generally applied in order to enhance the visualization of blood vessels by eliminating bones and surrounding tissues from X-ray images. The main limitation of these methods is the sensitivity to patient movement, which leads to artifacts and reduces the clinical value of the subtraction images. In this paper we present a novel method for rigid motion compensation with primary application to road mapping, frequently used in image-guided interventions. Using the general concept of image-based registration, we optimize the physical position and orientation of the C-arm X-ray device, thought of as the rigid 3D transformation accounting for the patient movement. The registration is carried out using a hierarchical optimization strategy and a similarity measure based on the variance of intensity differences, which has been shown to be most suitable for fluoroscopic images. Performance evaluation demonstrated the capabilities of the proposed approach to compensate for potential intra-operative patient motion, being more resilient to the fundamental problems of pure image-based registration.
Optimized radiographic spectra for small animal digital subtraction angiography
De Linming; Samei, Ehsan; Badea, Cristian T.; Yoshizumi, Terry T.; Allan Johnson, G.
2006-11-15
The increasing use of small animals in basic research has spurred interest in new imaging methodologies. Digital subtraction angiography (DSA) offers a particularly appealing approach to functional imaging in the small animal. This study examines the optimal x-ray, molybdenum (Mo) or tungsten (W) target sources, and technique to produce the highest quality small animal functional subtraction angiograms in terms of contrast and signal-difference-to-noise ratio squared (SdNR{sup 2}). Two limiting conditions were considered--normalization with respect to dose and normalization against tube loading. Image contrast and SdNR{sup 2} were simulated using an established x-ray model. DSA images of live rats were taken at two representative tube potentials for the W and Mo sources. Results show that for small animal DSA, the Mo source provides better contrast. However, with digital detectors, SdNR{sup 2} is the more relevant figure of merit. The W source operated at kVps>60 achieved a higher SdNR{sup 2}. The highest SdNR{sup 2} was obtained at voltages above 90 kVp. However, operation at the higher potential results in significantly greater dose and tube load and reduced contrast quantization. A reasonable tradeoff can be achieved at tube potentials at the beginning of the performance plateau, around 70 kVp, where the relative gain in SdNR{sup 2} is the greatest.
Tomographic digital subtraction angiography for lung perfusion estimation in rodents
Badea, Cristian T.; Hedlund, Laurence W.; De Lin, Ming; Boslego Mackel, Julie S.; Samei, Ehsan; Allan Johnson, G.
2007-05-15
In vivo measurements of perfusion present a challenge to existing small animal imaging techniques such as magnetic resonance microscopy, micro computed tomography, micro positron emission tomography, and microSPECT, due to combined requirements for high spatial and temporal resolution. We demonstrate the use of tomographic digital subtraction angiography (TDSA) for estimation of perfusion in small animals. TDSA augments conventional digital subtraction angiography (DSA) by providing three-dimensional spatial information using tomosynthesis algorithms. TDSA is based on the novel paradigm that the same time density curves can be reproduced in a number of consecutive injections of {mu}L volumes of contrast at a series of different angles of rotation. The capabilities of TDSA are established in studies on lung perfusion in rats. Using an imaging system developed in-house, we acquired data for four-dimensional (4D) imaging with temporal resolution of 140 ms, in-plane spatial resolution of 100 {mu}m, and slice thickness on the order of millimeters. Based on a structured experimental approach, we optimized TDSA imaging providing a good trade-off between slice thickness, the number of injections, contrast to noise, and immunity to artifacts. Both DSA and TDSA images were used to create parametric maps of perfusion. TDSA imaging has potential application in a number of areas where functional perfusion measurements in 4D can provide valuable insight into animal models of disease and response to therapeutics.
Background Subtraction Based on Three-Dimensional Discrete Wavelet Transform
Han, Guang; Wang, Jinkuan; Cai, Xi
2016-01-01
Background subtraction without a separate training phase has become a critical task, because a sufficiently long and clean training sequence is usually unavailable, and people generally thirst for immediate detection results from the first frame of a video. Without a training phase, we propose a background subtraction method based on three-dimensional (3D) discrete wavelet transform (DWT). Static backgrounds with few variations along the time axis are characterized by intensity temporal consistency in the 3D space-time domain and, hence, correspond to low-frequency components in the 3D frequency domain. Enlightened by this, we eliminate low-frequency components that correspond to static backgrounds using the 3D DWT in order to extract moving objects. Owing to the multiscale analysis property of the 3D DWT, the elimination of low-frequency components in sub-bands of the 3D DWT is equivalent to performing a pyramidal 3D filter. This 3D filter brings advantages to our method in reserving the inner parts of detected objects and reducing the ringing around object boundaries. Moreover, we make use of wavelet shrinkage to remove disturbance of intensity temporal consistency and introduce an adaptive threshold based on the entropy of the histogram to obtain optimal detection results. Experimental results show that our method works effectively in situations lacking training opportunities and outperforms several popular techniques. PMID:27043570
Background Subtraction Based on Three-Dimensional Discrete Wavelet Transform.
Han, Guang; Wang, Jinkuan; Cai, Xi
2016-01-01
Background subtraction without a separate training phase has become a critical task, because a sufficiently long and clean training sequence is usually unavailable, and people generally thirst for immediate detection results from the first frame of a video. Without a training phase, we propose a background subtraction method based on three-dimensional (3D) discrete wavelet transform (DWT). Static backgrounds with few variations along the time axis are characterized by intensity temporal consistency in the 3D space-time domain and, hence, correspond to low-frequency components in the 3D frequency domain. Enlightened by this, we eliminate low-frequency components that correspond to static backgrounds using the 3D DWT in order to extract moving objects. Owing to the multiscale analysis property of the 3D DWT, the elimination of low-frequency components in sub-bands of the 3D DWT is equivalent to performing a pyramidal 3D filter. This 3D filter brings advantages to our method in reserving the inner parts of detected objects and reducing the ringing around object boundaries. Moreover, we make use of wavelet shrinkage to remove disturbance of intensity temporal consistency and introduce an adaptive threshold based on the entropy of the histogram to obtain optimal detection results. Experimental results show that our method works effectively in situations lacking training opportunities and outperforms several popular techniques. PMID:27043570
NASA Astrophysics Data System (ADS)
Morales, Jose F.; Samtleben, Henning
2003-06-01
We review recent work on the holographic duals of type II and heterotic matrix string theories described by warped AdS3 supergravities. In particular, we compute the spectra of Kaluza-Klein primaries for type I, II supergravities on warped AdS3 × S7 and match them with the primary operators in the dual two-dimensional gauge theories. The presence of non-trivial warp factors and dilaton profiles requires a modification of the familiar dictionary between masses and 'scaling' dimensions of fields and operators. We present these modifications for the general case of domain wall/QFT correspondences between supergravities on warped AdSd+1 × Sq geometries and super Yang-Mills theories with 16 supercharges.
Compliant displacement-multiplying apparatus for microelectromechanical systems
Kota, Sridhar; Rodgers, M. Steven; Hetrick, Joel A.
2001-01-01
A pivotless compliant structure is disclosed that can be used to increase the geometric advantage or mechanical advantage of a microelectromechanical (MEM) actuator such as an electrostatic comb actuator, a capacitive-plate electrostatic actuator, or a thermal actuator. The compliant structure, based on a combination of interconnected flexible beams and cross-beams formed of one or more layers of polysilicon or silicon nitride, can provide a geometric advantage of from about 5:1 to about 60:1 to multiply a 0.25-3 .mu.m displacement provided by a short-stroke actuator so that such an actuator can be used to generate a displacement stroke of about 10-34 .mu.m to operate a ratchet-driven MEM device or a microengine. The compliant structure has less play than conventional displacement-multiplying devices based on lever arms and pivoting joints, and is expected to be more reliable than such devices. The compliant structure and an associated electrostatic or thermal actuator can be formed on a common substrate (e.g. silicon) using surface micromachining.
Interrupt-based Phase-locked Frequency Multiplier
NASA Technical Reports Server (NTRS)
Palumbo, Daniel L. (Inventor)
2006-01-01
A method aud system utilize a processor's digital timer and two interrupts to form a frequency multiplier. The first internipt's processing time window is definable by a first uumber of counts C(sub 1), of the digital timer while the second interrupt's processing time window is definable by a second number of counts C(sub 2) of the digital timer. A count value CV utilized by the systedmethod is based on a desired frequency multiplier N(sub 1), the timer clock rate, and the tiole required for one cycle of an input signal. The first interrupt is triggered upon completion of one cycle ofthe input sigual at which point the processing time window associated therewith begins. The second interrupt is triggered each time the timer's overflow signal is generated at which point the processing time window associated with the second interrupt begins. During the occurrence of the second interrupt's processing. the count value CV is modified to maintain the first interrupt's processing time window approximately centered between two of the second internipt's processing time windows.
Photooxygenation and gas-phase reactivity of multiply threaded pseudorotaxanes.
Nowosinski, Karol; Warnke, Stephan; Pagel, Kevin; Komáromy, Dávid; Jiang, Wei; Schalley, Christoph A
2016-04-01
The solution-phase photooxygenation of multiply threaded crown/ammonium pseudorotaxanes containing anthracene spacers is monitored by electrospray ionization Fourier-transform ion-cyclotron-resonance (ESI-FTICR) mass spectrometry. The oxygenated pseudorotaxanes are mass-selected and fragmented by infrared multiphoton dissociation (IRMPD) and/or collision-induced dissociation (CID) experiments and and their behavior compared to that of the non-oxygenated precursors. [4+2]Cycloreversion reactions lead to the loss of O2, when no other reaction channel with competitive energy demand is available. Thus, the release of molecular oxygen can serve as a reference reaction for the energy demand of other fragmentation reactions such as the dissociation of the crown/ammonium binding motifs. The photooxygenation induces curvature into the initially planar anthracene and thus significantly changes the geometry of the divalent, anthracene-spacered wheel. This is reflected in ion-mobility data. Coulomb repulsion in multiply charged pseudorotaxanes assists the oxygen loss as the re-planarization of the anthracene increases the distance between the two charges. PMID:27041657
Metal-metal multiply bonded complexes of technetium. Final report
Cotton, F.A.; Haefner, S.C.
1995-03-30
The primary objective of this project was to explore and develop the area of technetium metal-metal multiple bond chemistry. At the outset of the project, examples of metal-metal multiply bonded complexes of technetium were primarily limited to those supported by halide and carboxylate ligands. As a result, we intended to significantly expand the number of complexes containing Tc-Tc multiple bonds using ligands other than carboxylates or halides. In order to achieve this goal, the results obtained from years of dirhenium research was used as a guide for the development of new technetium compounds. Our emphasis, however, was on pursuing unanticipated results and exploiting the inherent differences between technetium and rhenium in order to develop chemistry beyond that which exists for rhenium. We have focused our attention on the preparation of dinuclear complexes with ligand sets that are known to support dinuclear metal-metal bonded cores in a variety of different metal oxidation states. Investigation of the consequences of electron addition and removal from metal-metal bonding manifold on the structural and physical properties of such dinuclear species will provide vital information regarding the electronic structure of Tc-Tc multiply bonded compounds.
Four-Quadrant Analog Multipliers Using G4-FETs
NASA Technical Reports Server (NTRS)
Mojarradi, Mohammad; Blalock, Benjamin; Christoloveanu, Sorin; Chen, Suheng; Akarvardar, Kerem
2006-01-01
Theoretical analysis and some experiments have shown that the silicon-on-insulator (SOI) 4-gate transistors known as G4-FETs can be used as building blocks of four-quadrant analog voltage multiplier circuits. Whereas a typical prior analog voltage multiplier contains between six and 10 transistors, it is possible to construct a superior voltage multiplier using only four G4-FETs. A G4-FET is a combination of a junction field-effect transistor (JFET) and a metal oxide/semiconductor field-effect transistor (MOSFET). It can be regarded as a single transistor having four gates, which are parts of a structure that affords high functionality by enabling the utilization of independently biased multiple inputs. The structure of a G4-FET of the type of interest here (see Figure 1) is that of a partially-depleted SOI MOSFET with two independent body contacts, one on each side of the channel. The drain current comprises of majority charge carriers flowing from one body contact to the other that is, what would otherwise be the side body contacts of the SOI MOSFET are used here as the end contacts [the drain (D) and the source (S)] of the G4-FET. What would otherwise be the source and drain of the SOI MOSFET serve, in the G4-FET, as two junction-based extra gates (JG1 and JG2), which are used to squeeze the channel via reverse-biased junctions as in a JFET. The G4-FET also includes a polysilicon top gate (G1), which plays the same role as does the gate in an accumulation-mode MOSFET. The substrate emulates a fourth MOS gate (G2). By making proper choices of G4-FET device parameters in conjunction with bias voltages and currents, one can design a circuit in which two input gate voltages (Vin1,Vin2) control the conduction characteristics of G4-FETs such that the output voltage (Vout) closely approximates a value proportional to the product of the input voltages. Figure 2 depicts two such analog multiplier circuits. In each circuit, there is the following: The input and output
Diamond Heat-Spreader for Submillimeter-Wave Frequency Multipliers
NASA Technical Reports Server (NTRS)
Lin, Robert H.; Schlecht, Erich T.; Chattopadhyay, Goutam; Gill, John J.; Mehdi, Imran; Siegel, Peter H.; Ward, John S.; Lee, Choonsup; Thomas, Bertrand C.; Maestrini, Alain
2010-01-01
The planar GaAs Shottky diode frequency multiplier is a critical technology for the local oscillator (LO) for submillimeter- wave heterodyne receivers due to low mass, tenability, long lifetime, and room-temperature operation. The use of a W-band (75-100 GHz) power amplifier followed by a frequency multiplier is the most common for submillimeter-wave sources. Its greatest challenge is to provide enough input power to the LO for instruments onboard future planetary missions. Recently, JPL produced 800 mW at 92.5 GHz by combining four MMICs in parallel in a balanced configuration. As more power at W-band is available to the multipliers, their power-handling capability be comes more important. High operating temperatures can lead to degradation of conversion efficiency or catastrophic failure. The goal of this innovation is to reduce the thermal resistance by attaching diamond film as a heat-spreader on the backside of multipliers to improve their power-handling capability. Polycrystalline diamond is deposited by hot-filament chemical vapor deposition (CVD). This diamond film acts as a heat-spreader to both the existing 250- and 300-GHz triplers, and has a high thermal conductivity (1,000-1,200 W/mK). It is approximately 2.5 times greater than copper (401 W/mK) and 20 times greater than GaAs (46 W/mK). It is an electrical insulator (resistivity approx. equals 10(exp 15) Ohms-cm), and has a low relative dielectric constant of 5.7. Diamond heat-spreaders reduce by at least 200 C at 250 mW of input power, compared to the tripler without diamond, according to thermal simulation. This superior thermal management provides a 100-percent increase in power-handling capability. For example, with this innovation, 40-mW output power has been achieved from a 250-GHz tripler at 350-mW input power, while the previous triplers, without diamond, suffered catastrophic failures. This breakthrough provides a stepping-stone for frequency multipliers-based LO up to 3 THz. The future work
Cadmium Subtraction Method for the Active Albedo Neutron Interrogation of Uranium
Worrall, Louise G.; Croft, Stephen
2015-02-01
This report describes work performed under the Next Generation Safeguards Initiative (NGSI) Cadmium Subtraction Project. The project objective was to explore the difference between the traditional cadmium (Cd) ratio signature and a proposed alternative Cd subtraction (or Cd difference) approach. The thinking behind the project was that a Cd subtraction method would provide a more direct measure of multiplication than the existing Cd ratio method. At the same time, it would be relatively insensitive to changes in neutron detection efficiency when properly calibrated. This is the first published experimental comparison and evaluation of the Cd ratio and Cd subtraction methods.
Holographic cusped Wilson loops in q-deformed AdS5 × S5 spacetime
NASA Astrophysics Data System (ADS)
Bai, Nan; Chen, Hui-Huang; Wu, Jun-Bao
2015-10-01
In this paper, a minimal surface in q-deformed AdS5×S5 with a cusp boundary is studied in detail. This minimal surface is dual to a cusped Wilson loop in dual field theory. We find that the area of the minimal surface has both logarithmic squared divergence and logarithmic divergence. The logarithmic squared divergence cannot be removed by either Legendre transformation or the usual geometric subtraction. We further make an analytic continuation to the Minkowski signature, taking the limit such that the two edges of the cusp become light-like, and extract the anomalous dimension from the coefficient of the logarithmic divergence. This anomalous dimension goes back smoothly to the results in the undeformed case when we take the limit that the deformation parameter goes to zero. Supported by National Natural Science Foundation of China (11105154, 11222549, 11275207), K. C. Wong Education Foundation and Youth Innovation Promotion Association of CAS
Unique-sample selection via near-infrared spectral subtraction
Honigs, D.E.; Hieftje, G.M.; Mark, H.L.; Hirschfeld, T.B.
1985-10-01
A method is described and tested for improving the training sample set in near-infrared diffuse-reflectance analysis (NIRA). Utilizing linear algebra techniques similar to spectral subtraction, this method selects the most spectrally unique samples from those in a larger pool. Upon being analyzed, these spectrally unique samples are found to have a significantly larger variation in their chemical compositions than the pool of samples from which they were selected. When the spectrally unique samples are incorporated into a NIRA training set, the resulting calibration is improved in two ways: first, the larger variations in sample composition help to make a NIRA calibration more robust and less subject to unexpected variations in the sample matrix; second, use of the spectrally unique samples reduces the time and effort involved in developing a NIRA method of analysis. 13 references, 2 figures, 7 tables.
Ambient-Light-Canceling Camera Using Subtraction of Frames
NASA Technical Reports Server (NTRS)
Morookian, John Michael
2004-01-01
The ambient-light-canceling camera (ALCC) is a proposed near-infrared electronic camera that would utilize a combination of (1) synchronized illumination during alternate frame periods and (2) subtraction of readouts from consecutive frames to obtain images without a background component of ambient light. The ALCC is intended especially for use in tracking the motion of an eye by the pupil center corneal reflection (PCCR) method. Eye tracking by the PCCR method has shown potential for application in human-computer interaction for people with and without disabilities, and for noninvasive monitoring, detection, and even diagnosis of physiological and neurological deficiencies. In the PCCR method, an eye is illuminated by near-infrared light from a lightemitting diode (LED). Some of the infrared light is reflected from the surface of the cornea. Some of the infrared light enters the eye through the pupil and is reflected from back of the eye out through the pupil a phenomenon commonly observed as the red-eye effect in flash photography. An electronic camera is oriented to image the user's eye. The output of the camera is digitized and processed by algorithms that locate the two reflections. Then from the locations of the centers of the two reflections, the direction of gaze is computed. As described thus far, the PCCR method is susceptible to errors caused by reflections of ambient light. Although a near-infrared band-pass optical filter can be used to discriminate against ambient light, some sources of ambient light have enough in-band power to compete with the LED signal. The mode of operation of the ALCC would complement or supplant spectral filtering by providing more nearly complete cancellation of the effect of ambient light. In the operation of the ALCC, a near-infrared LED would be pulsed on during one camera frame period and off during the next frame period. Thus, the scene would be illuminated by both the LED (signal) light and the ambient (background) light
Intermediate Palomar Transient Factory: Realtime Image Subtraction Pipeline
NASA Astrophysics Data System (ADS)
Cao, Yi; Nugent, Peter E.; Kasliwal, Mansi M.
2016-11-01
A fast-turnaround pipeline for realtime data reduction plays an essential role in discovering and permitting follow-up observations to young supernovae and fast-evolving transients in modern time-domain surveys. In this paper, we present the realtime image subtraction pipeline in the intermediate Palomar Transient Factory. By using high-performance computing, efficient databases, and machine-learning algorithms, this pipeline manages to reliably deliver transient candidates within 10 minutes of images being taken. Our experience in using high-performance computing resources to process big data in astronomy serves as a trailblazer to dealing with data from large-scale time-domain facilities in the near future.
Background Subtraction Approach based on Independent Component Analysis
Jiménez-Hernández, Hugo
2010-01-01
In this work, a new approach to background subtraction based on independent component analysis is presented. This approach assumes that background and foreground information are mixed in a given sequence of images. Then, foreground and background components are identified, if their probability density functions are separable from a mixed space. Afterwards, the components estimation process consists in calculating an unmixed matrix. The estimation of an unmixed matrix is based on a fast ICA algorithm, which is estimated as a Newton-Raphson maximization approach. Next, the motion components are represented by the mid-significant eigenvalues from the unmixed matrix. Finally, the results show the approach capabilities to detect efficiently motion in outdoors and indoors scenarios. The results show that the approach is robust to luminance conditions changes at scene. PMID:22219704
UNFOLD using a temporal subtraction and spectral energy comparison technique.
Wu, Yijing; Jeong, Eun-Kee; Parker, Dennis L; Alexander, Andrew L
2002-09-01
In dynamic MRI, several methods have been demonstrated to increase acquisition speed by decreasing the number of sequential phase encodings. The UNFOLD technique interleaves the measurements of k-space, reconstructs aliased images from each k-space interleaf, and applies a temporal low-pass filter to obtain the nonaliased images. However, low-pass filter resolution of the nonaliased images fails if there is overlap between the spatially aliased temporal spectra. In this study a subtraction method was used to remove the static portion of the image. The aliased and nonaliased dynamic portions are then resolved by comparing the temporal energy of bands in the power spectrum. This method was combined with the 3D 2 x 2 UNFOLD (a factor of 2 interleaves in two directions) technique. The combination resulted in a factor of 4 improvement in acquisition speed. Application of this method to a time-resolved, contrast-enhanced flow phantom study is presented.
Plasma tomographic reconstruction from tangentially viewing camera with background subtraction
Odstrčil, M.; Mlynář, J.; Weinzettl, V.; Háček, P.; Verdoolaege, G.; Berta, M.
2014-01-15
Light reflections are one of the main and often underestimated issues of plasma emissivity reconstruction in visible light spectral range. Metallic and other specular components of tokamak generate systematic errors in the optical measurements that could lead to wrong interpretation of data. Our analysis is performed at data from the tokamak COMPASS. It is a D-shaped tokamak with specular metallic vessel and possibility of the H-mode plasma. Data from fast visible light camera were used for tomographic reconstruction with background reflections subtraction to study plasma boundary. In this article, we show that despite highly specular tokamak wall, it is possible to obtain a realistic reconstruction. The developed algorithm shows robust results despite of systematic errors in the optical measurements and calibration. The motivation is to obtain an independent estimate of the plasma boundary shape.
Arbitrary cylinder color model for the codebook based background subtraction.
Zeng, Zhi; Jia, Jianyuan
2014-09-01
The codebook background subtraction approach is widely used in computer vision applications. One of its distinguished features is the cylinder color model used to cope with illumination changes. The performances of this approach depends strongly on the color model. However, we have found this color model is valid only if the spectrum components of the light source change in the same proportion. In fact, this is not true in many practical cases. In these cases, the performances of the approach would be degraded significantly. To tackle this problem, we propose an arbitrary cylinder color model with a highly efficient updating strategy. This model uses cylinders whose axes need not going through the origin, so that the cylinder color model is extended to much more general cases. Experimental results show that, with no loss of real-time performance, the proposed model reduces the wrong classification rate of the cylinder color model by more than fifty percent.
Background Subtraction Based on Color and Depth Using Active Sensors
Fernandez-Sanchez, Enrique J.; Diaz, Javier; Ros, Eduardo
2013-01-01
Depth information has been used in computer vision for a wide variety of tasks. Since active range sensors are currently available at low cost, high-quality depth maps can be used as relevant input for many applications. Background subtraction and video segmentation algorithms can be improved by fusing depth and color inputs, which are complementary and allow one to solve many classic color segmentation issues. In this paper, we describe one fusion method to combine color and depth based on an advanced color-based algorithm. This technique has been evaluated by means of a complete dataset recorded with Microsoft Kinect, which enables comparison with the original method. The proposed method outperforms the others in almost every test, showing more robustness to illumination changes, shadows, reflections and camouflage. PMID:23857259
[Digital subtraction angiography in otorhinolaryngology--preliminary report].
Liu, B; Wang, J; Bi, S
1994-01-01
The paper presents the preliminary experience with digital subtraction angiography (DSA) in otorhinolaryngology. This series included racemose hemangioma of the auricle in 3 cases, juvenile angiofibroma of nasopharynx in 4 cases, angioma in the retropharyngeal space in 1 case, tympanic body tumor in 1 case, traumatic epistaxis in 1 case, traumatic pseudoaneurysm in 1 case. The site, supply arteries, drainage veins of vascular tumors were shown with DSA. The intraoperative bleeding was reduced significantly by preoperative embolization of supply arteries to vascular tumors. The broken arteries of the traumatic epistaxis and the traumatic pseudoaneurysm were not only discovered but embolized. The indications and complications of DSA and measures for preventing and reducing complications were discussed.
Ultrathin Nanostructured Metals for Highly Transmissive Plasmonic Subtractive Color Filters
Zeng, Beibei; Gao, Yongkang; Bartoli, Filbert J.
2013-01-01
Plasmonic color filters employing a single optically-thick nanostructured metal layer have recently generated considerable interest as an alternative to colorant-based color filtering technologies, due to their reliability, ease of fabrication, and high color tunability. However, their relatively low transmission efficiency (~30%) needs to be significantly improved for practical applications. The present work reports, for the first time, a novel plasmonic subtractive color filtering scheme that exploits the counter-intuitive phenomenon of extraordinary low transmission (ELT) through an ultrathin nanostructured metal film. This approach relies on a fundamentally different color filtering mechanism than that of existing plasmonic additive color filters, and achieves unusually high transmission efficiencies of 60 ~ 70% for simple architectures. Furthermore, owing to short-range interactions of surface plasmon polaritons at ELT resonances, our design offers high spatial resolution color filtering with compact pixel size close to the optical diffraction limit (~λ/2), creating solid applications ranging from imaging sensors to color displays. PMID:24100869
PSF subtraction to search for distant Jupiters with SPITZER
NASA Astrophysics Data System (ADS)
Rameau, Julien; Artigau, Etienne; Baron, Frédérique; Lafrenière, David; Doyon, Rene; Malo, Lison; Naud, Marie-Eve; Delorme, Philippe; Janson, Markus; Albert, Loic; Gagné, Jonathan; Beichman, Charles
2015-12-01
In the course of the search for extrasolar planets, a focus has been made towards rocky planets very close (within few AUs) to their parent stars. However, planetary systems might host gas giants as well, possibly at larger separation from the central star. Direct imaging is the only technique able to probe the outer part of planetary systems. With the advent of the new generation of planet finders like GPI and SPHERE, extrasolar systems are now studied at the solar system scale. Nevertheless, very extended planetary systems do exist and have been found (Gu Ps, AB Pic b, etc.). They are easier to detect and characterize. They are also excellent proxy for close-in gas giants that are detected from the ground. These planets have no equivalent in our solar system and their origin remain a matter of speculation. In this sense, studying planetary systems from its innermost to its outermost part is therefore mandatory to have a clear understanding of its architecture, hence hints of its formation and evolution. We are carrying out a space-based survey using SPITZER to search for distant companions around a well-characterized sample of 120 young and nearby stars. We designed an observing strategy that allows building a very homogeneous PSF library. With this library, we perform a PSF subtraction to search for planets from 10’’ down to 1’’. In this poster, I will present the library, the different algorithms used to subtract the PSF, and the promising detection sensitivity that we are able to reach with this survey. This project to search for the most extreme planetary systems is unique in the exoplanet community. It is also the only realistic mean of directly imaging and subsequently obtaining spectroscopy of young Saturn or Jupiter mass planets in the JWST-era.
Multiply glazed window and door assemblies with screened breathing passages
Chludil, S.T.
1987-04-14
This patent describes a multiply glazed, vented window or door assembly comprising: spaced apart glass panes sealably secured perimetrally in parallel side sash members and parallel upper and lower sash members. At least one of the sash members has in its outer surface, a linear groove perimetrally aligned with the space between the panes and further having a breathing port extending from the marginal wall of the groove through to the space between the panes; an elongate flat plate having fine perforations and parallel end flanges projecting generally perpendicularly therefrom, fitting into and sealing off the groove at spaced distances from the port to provide an air circulation manifold under the plate. The plate is sufficiently long to have sufficient perforations to provide a cross-sectional area which correlates with the cross-sectional area of the port; and means for securing the plate in place.
Present status of beryllide R&D as neutron multiplier
NASA Astrophysics Data System (ADS)
Kawamura, H.; Takahashi, H.; Yoshida, N.; Mishima, Y.; Ishida, K.; Iwadachi, T.; Cardella, A.; van der Laan, J. G.; Uchida, M.; Munakata, K.; Sato, Y.; Shestakov, V.; Tanaka, S.
2004-08-01
Since 1997, beryllide application as the neutron multiplier has been proposed in Japan and preliminary investigations revealed that some beryllides such as Be 12Ti have excellent properties compared with beryllium metal. Recently, several international R&D programs were performed. Some pebbles of modified Be 12Ti that included the Be phase were obtained by the rotating electrode method. Basic characterization using HIPped Be 12Ti has also been performed. Preliminary experiments indicate that compatibility with stainless steel and tritium breeder materials, deuterium release, natural oxidation and oxidations by steam interaction were better than the behavior of beryllium. Preliminary neutron irradiation effects were studied in JMTR and by charged particle irradiation. It was observed that Be 12Ti has less radiation damage than beryllium. In a future experiment, Japanese Be 12Ti samples will be included in a long European irradiation program on beryllium to produce up to 6000 appm He. This is an IEA collaborative experiment, to evaluate neutron irradiation effects.
Imaging With Nature: Compressive Imaging Using a Multiply Scattering Medium
Liutkus, Antoine; Martina, David; Popoff, Sébastien; Chardon, Gilles; Katz, Ori; Lerosey, Geoffroy; Gigan, Sylvain; Daudet, Laurent; Carron, Igor
2014-01-01
The recent theory of compressive sensing leverages upon the structure of signals to acquire them with much fewer measurements than was previously thought necessary, and certainly well below the traditional Nyquist-Shannon sampling rate. However, most implementations developed to take advantage of this framework revolve around controlling the measurements with carefully engineered material or acquisition sequences. Instead, we use the natural randomness of wave propagation through multiply scattering media as an optimal and instantaneous compressive imaging mechanism. Waves reflected from an object are detected after propagation through a well-characterized complex medium. Each local measurement thus contains global information about the object, yielding a purely analog compressive sensing method. We experimentally demonstrate the effectiveness of the proposed approach for optical imaging by using a 300-micrometer thick layer of white paint as the compressive imaging device. Scattering media are thus promising candidates for designing efficient and compact compressive imagers. PMID:25005695
Rocket Propulsion Through Multiply Charged Ions From a Mirror Plasma
NASA Astrophysics Data System (ADS)
Leung, L.; Petty, C. C.; Evans, T. E.
2006-10-01
Plasma propulsion is of interest for space exploration because the high exit velocity of the propellant, compared to that of chemical means, generates a high final spacecraft velocity with reduced propellant mass. This project evaluates the viability of using plasma in a magnetic mirror to produce multiply charged ions as propellant. Electron cyclotron heating of a mirror plasma produces deeply trapped hot electrons which strip heavy ions of electrons. The ambipolar potential accelerates the greatly charged ions to high velocity as they exit the end of the magnetic mirror open to space, generating thrust. We model the distribution of ion charge states to include all relevant atomic processes using the conservation of particle and energy equations in tandem with cross-sections from the ADAS database. The system of equations is then optimized to determine the feasibility of plasma propulsion. The results of this model in a high- density rocket regime are benchmarked against experimental data in low-density mirror plasmas.
A Lagrange multiplier based divide and conquer finite element algorithm
NASA Technical Reports Server (NTRS)
Farhat, C.
1991-01-01
A novel domain decomposition method based on a hybrid variational principle is presented. Prior to any computation, a given finite element mesh is torn into a set of totally disconnected submeshes. First, an incomplete solution is computed in each subdomain. Next, the compatibility of the displacement field at the interface nodes is enforced via discrete, polynomial and/or piecewise polynomial Lagrange multipliers. In the static case, each floating subdomain induces a local singularity that is resolved very efficiently. The interface problem associated with this domain decomposition method is, in general, indefinite and of variable size. A dedicated conjugate projected gradient algorithm is developed for solving the latter problem when it is not feasible to explicitly assemble the interface operator. When implemented on local memory multiprocessors, the proposed methodology requires less interprocessor communication than the classical method of substructuring. It is also suitable for parallel/vector computers with shared memory and compares favorably with factorization based parallel direct methods.
Multigroup diffusion preconditioners for multiplying fixed-source transport problems
NASA Astrophysics Data System (ADS)
Roberts, Jeremy A.; Forget, Benoit
2014-10-01
Several preconditioners based on multigroup diffusion are developed for application to multiplying fixed-source transport problems using the discrete ordinates method. By starting from standard, one-group, diffusion synthetic acceleration (DSA), a multigroup diffusion preconditioner is constructed that shares the same fine mesh as the transport problem. As a cheaper but effective alternative, a two-grid, coarse-mesh, multigroup diffusion preconditioner is examined, for which a variety of homogenization schemes are studied to generate the coarse mesh operator. Finally, a transport-corrected diffusion preconditioner based on application of the Newton-Shulz algorithm is developed. The results of several numerical studies indicate the coarse-mesh, diffusion preconditioners work very well. In particular, a coarse-mesh, transport-corrected, diffusion preconditioner reduced the computational time of multigroup GMRES by up to a factor of 17 and outperformed best-case Gauss-Seidel results by over an order of magnitude for all problems studied.
Multiplying steady-state culture in multi-reactor system.
Erm, Sten; Adamberg, Kaarel; Vilu, Raivo
2014-11-01
Cultivation of microorganisms in batch experiments is fast and economical but the conditions therein change constantly, rendering quantitative data interpretation difficult. By using chemostat with controlled environmental conditions the physiological state of microorganisms is fixed; however, the unavoidable stabilization phase makes continuous methods resource consuming. Material can be spared by using micro scale devices, which however have limited analysis and process control capabilities. Described herein are a method and a system combining the high throughput of batch with the controlled environment of continuous cultivations. Microorganisms were prepared in one bioreactor followed by culture distribution into a network of bioreactors and continuation of independent steady state experiments therein. Accelerostat cultivation with statistical analysis of growth parameters demonstrated non-compromised physiological state following distribution, thus the method effectively multiplied steady state culture of microorganisms. The theoretical efficiency of the system was evaluated in inhibitory compound analysis using repeated chemostat to chemostat transfers.
Regulated high efficiency, lightweight capacitor-diode multiplier dc to dc converter
NASA Technical Reports Server (NTRS)
Harrigill, W. T., Jr.; Myers, I. T. (Inventor)
1978-01-01
A voltage multiplier having a capacitor-diode voltage multiplying network is disclosed which is fed with voltage pulses from a dc source through a first switching means. Pulses of a second polarity are also supplied through a second switching means to the input of the capacitor-diode voltage multiplier from a second dc source whose voltage is adjustable to change the voltage of the pulses of second polarity. The switching means are alternately rendered conducting by signals from a control circuit. The second dc source may be controlled by a voltage comparator which compares the output voltage of the capacitor-diode voltage multiplier to the reference source.
Planar varactor frequency multiplier devices with blocking barrier
NASA Technical Reports Server (NTRS)
Lieneweg, Udo (Inventor); Frerking, Margaret A. (Inventor); Maserjian, Joseph (Inventor)
1994-01-01
The invention relates to planar varactor frequency multiplier devices with a heterojunction blocking barrier for near millimeter wave radiation of moderate power from a fundamental input wave. The space charge limitation of the submillimeter frequency multiplier devices of the BIN(sup +) type is overcome by a diode structure comprising an n(sup +) doped layer of semiconductor material functioning as a low resistance back contact, a layer of semiconductor material with n-type doping functioning as a drift region grown on the back contact layer, a delta doping sheet forming a positive charge at the interface of the drift region layer with a barrier layer, and a surface metal contact. The layers thus formed on an n(sup +) doped layer may be divided into two isolated back-to-back BNN(sup +) diodes by separately depositing two surface metal contacts. By repeating the sequence of the drift region layer and the barrier layer with the delta doping sheet at the interfaces between the drift and barrier layers, a plurality of stacked diodes is formed. The novelty of the invention resides in providing n-type semiconductor material for the drift region in a GaAs/AlGaAs structure, and in stacking a plurality of such BNN(sup +) diodes stacked for greater output power with and connected back-to-back with the n(sup +) GaAs layer as an internal back contact and separate metal contact over an AlGaAs barrier layer on top of each stack.
Agricultural Education: Value Adding.
ERIC Educational Resources Information Center
Riesenberg, Lou E.; And Others
1989-01-01
This issue develops the theme of "Agricultural Education--Value Adding." The concept value adding has been a staple in the world of agricultural business for describing adding value to a commodity that would profit the producer and the local community. Agricultural education should add value to individuals and society to justify agricultural…
Kokkinakis, Kostas; Runge, Christina; Tahmina, Qudsia; Hu, Yi
2015-07-01
The smearing effects of room reverberation can significantly impair the ability of cochlear implant (CI) listeners to understand speech. To ameliorate the effects of reverberation, current dereverberation algorithms focus on recovering the direct sound from the reverberated signal by inverse filtering the reverberation process. This contribution describes and evaluates a spectral subtraction (SS) strategy capable of suppressing late reflections. Late reflections are the most detrimental to speech intelligibility by CI listeners as reverberation increases. By tackling only the late part of reflections, it is shown that users of CI devices can benefit from the proposed strategy even in highly reverberant rooms. The proposed strategy is also compared against an ideal reverberant (binary) masking approach. Speech intelligibility results indicate that the proposed SS solution is able to suppress additive reverberant energy to a degree comparable to that achieved by an ideal binary mask. The added advantage is that the SS strategy proposed in this work can allow for a potentially real-time implementation in clinical CI processors.
ERIC Educational Resources Information Center
de la Torre, Jimmy; Douglas, Jeffrey A.
2008-01-01
This paper studies three models for cognitive diagnosis, each illustrated with an application to fraction subtraction data. The objective of each of these models is to classify examinees according to their mastery of skills assumed to be required for fraction subtraction. We consider the DINA model, the NIDA model, and a new model that extends the…
Efficiency and Flexibility of Indirect Addition in the Domain of Multi-Digit Subtraction
ERIC Educational Resources Information Center
Torbeyns, Joke; Ghesquiere, Pol; Verschaffel, Lieven
2009-01-01
This article discusses the characteristics of the indirect addition strategy (IA) in the domain of multi-digit subtraction. In two studies, adults' use of IA on three-digit subtractions with a small, medium, or large difference between the integers was analysed using the choice/no-choice method. Results from both studies indicate that adults…
Putting Essential Understanding of Addition and Subtraction into Practice: Pre-K-2
ERIC Educational Resources Information Center
Caldwell, Janet H.; Kobett, Beth; Karp, Karen
2014-01-01
Do your students have the incorrect idea that addition "makes numbers bigger" and subtraction "makes numbers smaller"? Do they believe that subtraction is always "taking away"? What tasks can you offer--what questions can you ask--to determine what your students know or don't know--and move them forward in their…
The Use of Procedural Knowledge in Simple Addition and Subtraction Problems
ERIC Educational Resources Information Center
Fayol, Michel; Thevenot, Catherine
2012-01-01
In a first experiment, adults were asked to solve one-digit additions, subtractions and multiplications. When the sign appeared 150 ms before the operands, addition and subtraction were solved faster than when the sign and the operands appeared simultaneously on screen. This priming effect was not observed for multiplication problems. A second…
ERIC Educational Resources Information Center
Slaughter, Virginia; Kamppi, Dorian; Paynter, Jessica
2006-01-01
Two experiments were conducted to test the hypothesis that toddlers have access to an analog-magnitude number representation that supports numerical reasoning about relatively large numbers. Three-year-olds were presented with subtraction problems in which initial set size and proportions subtracted were systematically varied. Two sets of cookies…
Mental Computation or Standard Algorithm? Children's Strategy Choices on Multi-Digit Subtractions
ERIC Educational Resources Information Center
Torbeyns, Joke; Verschaffel, Lieven
2016-01-01
This study analyzed children's use of mental computation strategies and the standard algorithm on multi-digit subtractions. Fifty-eight Flemish 4th graders of varying mathematical achievement level were individually offered subtractions that either stimulated the use of mental computation strategies or the standard algorithm in one choice and two…
Chu, Kai Chuan
2012-01-01
Objectives Noise reduction using wavelet thresholding of multitaper estimators (WTME) and geometric approach to spectral subtraction (GASS) can improve speech quality of noisy sound for speech coding strategy. This study used Perceptual Evaluation of Speech Quality (PESQ) to assess the performance of the WTME and GASS for speech coding strategy. Methods This study included 25 Mandarin sentences as test materials. Environmental noises including the air-conditioner, cafeteria and multi-talker were artificially added to test materials at signal to noise ratio (SNR) of -5, 0, 5, and 10 dB. HiRes 120 vocoder WTME and GASS noise reduction process were used in this study to generate sound outputs. The sound outputs were measured by the PESQ to evaluate sound quality. Results Two figures and three tables were used to assess the speech quality of the sound output of the WTME and GASS. Conclusion There is no significant difference between the overall performance of sound quality in both methods, but the geometric approach to spectral subtraction method is slightly better than the wavelet thresholding of multitaper estimators. PMID:22701151
High performance multiplier processor for use with aerospace microcomputers. [MC 68000
Pierce, P.E.
1980-01-01
An MC 68000-based microcomputer including a hardware multiplier processor has been designed for a re-entry vehicle navigation and control application. The microcomputer is discussed with emphasis on the multiplier processor architecture, software control, and theory of operation. 2 figures.
How to Help Your Child: A Guide for Parents of Multiply Handicapped Children.
ERIC Educational Resources Information Center
Doyle, Phyllis B.; And Others
Developed by Project TRAC--Training/Resources Acquisition and Control, the three part guide is for parents of multiply handicapped children. Part 1 examines a public school training program for multiply handicapped children. Part 2 gives suggestions for activities that can make home life easier and at the same time provide learning experiences for…
Singular Lagrangian, Hamiltonization and Jacobi last multiplier for certain biological systems
NASA Astrophysics Data System (ADS)
Guha, Partha; Ghose Choudhury, Anindya
2013-07-01
We study the construction of singular Lagrangians using Jacobi's last multiplier (JLM). We also demonstrate the significance of the last multiplier in Hamiltonian theory by explicitly constructing the Hamiltonian of the Host-Parasite model and a Lotka-Volterra mutualistic system, both of which are well known first-order systems of differential equations arising in biology.
NASA Astrophysics Data System (ADS)
Ammon, Martin; Erdmenger, Johanna; Meyer, René; O'Bannon, Andy; Wrase, Timm
2009-11-01
Aharony, Bergman, Jafferis, and Maldacena have proposed that the low-energy description of multiple M2-branes at a Bbb C4/Bbb Zk singularity is a (2+1)-dimensional Script N = 6 supersymmetric U(Nc) × U(Nc) Chern-Simons matter theory, the ABJM theory. In the large-Nc limit, its holographic dual is supergravity in AdS4 × S7/Bbb Zk. We study various ways to add fields that transform in the fundamental representation of the gauge groups, i.e. flavor fields, to the ABJM theory. We work in a probe limit and perform analyses in both the supergravity and field theory descriptions. In the supergravity description we find a large class of supersymmetric embeddings of probe flavor branes. In the field theory description, we present a general method to determine the couplings of the flavor fields to the fields of the ABJM theory. We then study four examples in detail: codimension-zero Script N = 3 supersymmetric flavor, described in supergravity by Kaluza-Klein monopoles or D6-branes; codimension-one Script N = (0,6) supersymmetric chiral flavor, described by D8-branes; codimension-one Script N = (3,3) supersymmetric non-chiral flavor, described by M5/D4-branes; codimension-two Script N = 4 supersymmetric flavor, described by M2/D2-branes. Finally we discuss special physical equivalences between brane embeddings in M-theory, and their interpretation in the field theory description.
Fast background subtraction for moving cameras based on nonparametric models
NASA Astrophysics Data System (ADS)
Sun, Feng; Qin, Kaihuai; Sun, Wei; Guo, Huayuan
2016-05-01
In this paper, a fast background subtraction algorithm for freely moving cameras is presented. A nonparametric sample consensus model is employed as the appearance background model. The as-similar-as-possible warping technique, which obtains multiple homographies for different regions of the frame, is introduced to robustly estimate and compensate the camera motion between the consecutive frames. Unlike previous methods, our algorithm does not need any preprocess step for computing the dense optical flow or point trajectories. Instead, a superpixel-based seeded region growing scheme is proposed to extend the motion cue based on the sparse optical flow to the entire image. Then, a superpixel-based temporal coherent Markov random field optimization framework is built on the raw segmentations from the background model and the motion cue, and the final background/foreground labels are obtained using the graph-cut algorithm. Extensive experimental evaluations show that our algorithm achieves satisfactory accuracy, while being much faster than the state-of-the-art competing methods.
Removal of interference from fetal MEG by frequency dependent subtraction
Vrba, J.; McCubbin, J.; Govindan, R.B.; Vairavan, S.; Murphy, P.; Preissl, H.; Lowery, C.L.; Eswaran, H.
2011-01-01
Fetal magnetoencephalography (fMEG) recordings are contaminated by maternal and fetal magnetocardiography (MCG) signals and by other biological and environmental interference. Currently, all methods for the attenuation of these signals are based on a time-domain approach. We have developed and tested a frequency dependent procedure for removal of MCG and other interference from the fMEG recordings. The method uses a set of reference channels and performs subtraction of interference in the frequency domain (SUBTR). The interference-free frequency domain signals are converted back to the time domain. We compare the performance of the frequency dependent approach with our present approach for MCG attenuation based on orthogonal projection (OP). SUBTR has an advantage over OP and similar template approaches because it removes not only the MCG but also other small amplitude biological interference, avoids the difficulties with inaccurate determination of the OP operator, provides more consistent and stable fMEG results, does not cause signal redistribution, and if references are selected judiciously, it does not reduce fMEG signal amplitude. SUBTR was found to perform well in simulations and on real fMEG recordings, and has a potential to improve the detection of fetal brain signals. The SUBTR removes interference without the need for a model of the individual interference sources. The method may be of interest for any sensor array noise reduction application where signal-free reference channels are available. PMID:21930216
Subtractive transcriptomics : establishing polarity drives human endothelial morphogenesis
Glesne, D. A.; Zhang, W.; Mandava, S.; Ursos, L.; Buell, M. E.; Makowski, L.; Rodi, D. J.; Biosciences Division
2006-04-15
Although investigations of mature normal and tumor-derived capillaries have resulted in characterization of these structures at the phenotypic level, less is known regarding the initial molecular cues for cellular assembly of endothelial cells into human capillaries. Here, we employ a novel combination of microenvironmental manipulation and microarray data filtration over narrowly delineated temporal data series to identify the morphogenesis component apart from the proliferation component, as pooled human microvascular-derived endothelial cells are induced to form capillary-like structures in vitro in a murine tumor-derived matrix. The 217 morphogenesis-specific genes identified using this subtractive transcriptomics approach are mostly independent of the angiogenic proteins currently used as therapeutic targets for aberrant angiogenesis. Quantitative real-time PCR was used to validate 20% of these transcripts. Immunofluorescent analysis of proliferating and tube-forming cells validates at the protein level the morphogenesis-specific expression pattern of 16 of the 217 gene products identified. The transcripts that are selectively up-regulated in tube-forming endothelial cells reveal a temporal expression pattern of genes primarily associated with intracellular trafficking, guided migration, cytoskeletal reorganization, cellular adhesion, and proliferation inhibition. These data show that a sequential upregulation of genes that establish and maintain polarity occurs during migration and morphogenesis of in vitro human endothelial cells undergoing tubulogenesis; some of which may well be effective as novel antiangiogenic drug targets.
Subtractive fuzzy classifier based driver distraction levels classification using EEG.
Wali, Mousa Kadhim; Murugappan, Murugappan; Ahmad, Badlishah
2013-09-01
[Purpose] In earlier studies of driver distraction, researchers classified distraction into two levels (not distracted, and distracted). This study classified four levels of distraction (neutral, low, medium, high). [Subjects and Methods] Fifty Asian subjects (n=50, 43 males, 7 females), age range 20-35 years, who were free from any disease, participated in this study. Wireless EEG signals were recorded by 14 electrodes during four types of distraction stimuli (Global Position Systems (GPS), music player, short message service (SMS), and mental tasks). We derived the amplitude spectrum of three different frequency bands, theta, alpha, and beta of EEG. Then, based on fusion of discrete wavelet packet transforms and fast fourier transform yield, we extracted two features (power spectral density, spectral centroid frequency) of different wavelets (db4, db8, sym8, and coif5). Mean ± SD was calculated and analysis of variance (ANOVA) was performed. A fuzzy inference system classifier was applied to different wavelets using the two extracted features. [Results] The results indicate that the two features of sym8 posses highly significant discrimination across the four levels of distraction, and the best average accuracy achieved by the subtractive fuzzy classifier was 79.21% using the power spectral density feature extracted using the sym8 wavelet. [Conclusion] These findings suggest that EEG signals can be used to monitor distraction level intensity in order to alert drivers to high levels of distraction.
BRIGHT SOURCE SUBTRACTION REQUIREMENTS FOR REDSHIFTED 21 cm MEASUREMENTS
Datta, A.; Bowman, J. D.; Carilli, C. L.
2010-11-20
The H I 21 cm transition line is expected to be an important probe into the cosmic dark ages and epoch of reionization. Foreground source removal is one of the principal challenges for the detection of this signal. This paper investigates the extragalactic point source contamination and how accurately bright sources ({approx}>1 Jy) must be removed in order to detect 21 cm emission with upcoming radio telescopes such as the Murchison Widefield Array. We consider the residual contamination in 21 cm maps and power spectra due to position errors in the sky model for bright sources, as well as frequency-independent calibration errors. We find that a source position accuracy of 0.1 arcsec will suffice for detection of the H I power spectrum. For calibration errors, 0.05% accuracy in antenna gain amplitude is required in order to detect the cosmic signal. Both sources of subtraction error produce residuals that are localized to small angular scales, k{sub perpendicular} {approx}> 0.05 Mpc{sup -1}, in the two-dimensional power spectrum.
On-Chip Power-Combining for High-Power Schottky Diode Based Frequency Multipliers
NASA Technical Reports Server (NTRS)
Siles Perez, Jose Vicente (Inventor); Chattopadhyay, Goutam (Inventor); Lee, Choonsup (Inventor); Schlecht, Erich T. (Inventor); Jung-Kubiak, Cecile D. (Inventor); Mehdi, Imran (Inventor)
2015-01-01
A novel MMIC on-chip power-combined frequency multiplier device and a method of fabricating the same, comprising two or more multiplying structures integrated on a single chip, wherein each of the integrated multiplying structures are electrically identical and each of the multiplying structures include one input antenna (E-probe) for receiving an input signal in the millimeter-wave, submillimeter-wave or terahertz frequency range inputted on the chip, a stripline based input matching network electrically connecting the input antennas to two or more Schottky diodes in a balanced configuration, two or more Schottky diodes that are used as nonlinear semiconductor devices to generate harmonics out of the input signal and produce the multiplied output signal, stripline based output matching networks for transmitting the output signal from the Schottky diodes to an output antenna, and an output antenna (E-probe) for transmitting the output signal off the chip into the output waveguide transmission line.
NASA Astrophysics Data System (ADS)
Adamo, Tim; Skinner, David; Williams, Jack
2016-08-01
We consider the application of twistor theory to five-dimensional anti-de Sitter space. The twistor space of AdS5 is the same as the ambitwistor space of the four-dimensional conformal boundary; the geometry of this correspondence is reviewed for both the bulk and boundary. A Penrose transform allows us to describe free bulk fields, with or without mass, in terms of data on twistor space. Explicit representatives for the bulk-to-boundary propagators of scalars and spinors are constructed, along with twistor action functionals for the free theories. Evaluating these twistor actions on bulk-to-boundary propagators is shown to produce the correct two-point functions.
NASA Astrophysics Data System (ADS)
Bena, Iosif; Heurtier, Lucien; Puhm, Andrea
2016-05-01
It was argued in [1] that the five-dimensional near-horizon extremal Kerr (NHEK) geometry can be embedded in String Theory as the infrared region of an infinite family of non-supersymmetric geometries that have D1, D5, momentum and KK monopole charges. We show that there exists a method to embed these geometries into asymptotically- {AdS}_3× {S}^3/{{Z}}_N solutions, and hence to obtain infinite families of flows whose infrared is NHEK. This indicates that the CFT dual to the NHEK geometry is the IR fixed point of a Renormalization Group flow from a known local UV CFT and opens the door to its explicit construction.
Shadows, currents, and AdS fields
Metsaev, R. R.
2008-11-15
Conformal totally symmetric arbitrary spin currents and shadow fields in flat space-time of dimension greater than or equal to four are studied. A gauge invariant formulation for such currents and shadow fields is developed. Gauge symmetries are realized by involving the Stueckelberg fields. A realization of global conformal boost symmetries is obtained. Gauge invariant differential constraints for currents and shadow fields are obtained. AdS/CFT correspondence for currents and shadow fields and the respective normalizable and non-normalizable solutions of massless totally symmetric arbitrary spin AdS fields are studied. The bulk fields are considered in a modified de Donder gauge that leads to decoupled equations of motion. We demonstrate that leftover on shell gauge symmetries of bulk fields correspond to gauge symmetries of boundary currents and shadow fields, while the modified de Donder gauge conditions for bulk fields correspond to differential constraints for boundary conformal currents and shadow fields. Breaking conformal symmetries, we find interrelations between the gauge invariant formulation of the currents and shadow fields, and the gauge invariant formulation of massive fields.
Development of Resistive Electrode Gas Electron Multiplier (RE-GEM)
NASA Technical Reports Server (NTRS)
Yoshikawa, A.; Tamagawa, T.; Iwahashi, T.; Asami, F.; Takeuchi, Y.; Hayato, A.; Hamagaki, H.; Gunji, T.; Akimoto, R.; Nukariya, A.; Hayashi, S.; Ueno, K.; Ochi, A.; Oliveria, R.
2012-01-01
We successfully produced Resistive-Electrode Gas Electron Multiplier (RE-GEM) which has resistive electrodes instead of the metal ones which are employed for the standard GEM foils. RE-GEM has a resistive electrode of 25 micron-thick and an insulator layer of 100 micron-thick. The hole structure of RE-GEM is a single conical with the wider and narrower hole diameters of 80 micron and 60 micron, respectively. A hole pitch of RE-GEM is 140 micron. We obtained the maximum gain of about 600 and the typical energy resolution of about 20% (FWHM) at an applied voltage between the resistive electrodes of 620 V, using a collimated 8 keV X-rays from a generator in a gas mixture of 70% Ar and 30% CO2 by volume at the atmospheric pressure. We measured the effective gain as a function of the electric field of the drift region and obtained the maximum gain at an drift field of 0.5 kV/cm.
Measurement Of Gas Electron Multiplier (GEM) Detector Characteristics
Park, Seongtae; Baldelomar, Edwin; Sosebee, Mark; White, Andy; Yu, Jaehoon; Park, Kwangjune
2011-06-01
The High Energy Physics group of the University of Texas at Arlington has been developing gas electron multiplier detectors to use them as sensitive gap detectors in digital hadron calorimeters for the International Linear Collider, a future high energy particle accelerator. For this purpose, we constructed numerous GEM detectors that employ double GEM layers. In this study, two kinds of prototype GEM detectors were tested; one with 28x28 cm{sup 2} active area double GEM structure with a 3 mm drift gap, a 1 mm transfer gap and a 1 mm induction gap and the other with two 3x3 cm{sup 2} GEM foils in the amplifier stage with a 5 mm drift gap, a 2 mm transfer gap and a 1 mm induction gap. The detectors' characteristics from exposure to high-energy charged particles and other radiations were measured using cosmic rays and {sup 55}Fe radioactive source. From the {sup 55}Fe tests, we observed two well separated characteristic X-ray emission peaks and confirmed the detectors' functionality. We also measured chamber gains to be over 6000 at a high voltage of 395 V across each GEM electrode. The responses to cosmic rays show the spectra that fit well to Landau distributions as expected from minimum ionizing particles.
Production and properties of singly and multiply charged Kr clusters
Lezius, M.; Scheier, P.; Stamatovic, A.; Mark, T. D.
1989-09-01
Kr clusters produced in a supersonic nozzle expansion have been studied by electron impact ionization mass spectrometry. Mass resolved spectra (with /ital n/ up to 180) show two homologous series consisting of Kr/sup +//sub /ital n// and Kr/sup 2+//sub /ital n// ions. The distribution of Kr/sup +//sub /ital n// ions shows distinct magic number effects, the observed abundance anomalies being very similar to the ones observed in Ar and Xe. This confirms the superior stability of closed-shell and -subshell icosahedral structures. Moreover, we have found evidence for the occurrence of Kr/sup 3+//sub /ital n// and Kr/sup 4+//sub /ital n// ions. It was possible to determine appearance sizes of these multiply charged cluster ions (yielding /ital n//sub 2/=69, /ital n//sub 3/=156, and /ital n//sub 4/=264), and to study the electron energy dependence of singly and doubly charged cluster ions (yielding a linear threshold law). These results are discussed in view of various theoretical considerations and previous results where available.
Electron interactions with positively and negatively multiply charged biomolecular clusters
NASA Astrophysics Data System (ADS)
Feketeová, Linda
2012-07-01
Interactions of positively and negatively multiply charged biomolecular clusters with low-energy electrons, from ~ 0 up to 50 eV of electron energy, were investigated in a high resolution Fourier-Transform Ion Cyclotron Resonance mass spectrometer equipped with an electrospray ionisation source. Electron-induced dissociation reactions of these clusters depend on the energy of the electrons, the size and the charge state of the cluster. The positively charged clusters [Mn+2H]2+ of zwitterionic betaines, M = (CH3)2XCH2CO2 (X = NCH3 and S), do capture an electron in the low electron energy region (< 10 eV). At higher electron energies neutral evaporation from the cluster becomes competitive with Coulomb explosion. In addition, a series of singly charged fragments arise from bond cleavage reactions, including decarboxylation and CH3 group transfer, due to the access of electronic excited states of the precursor ions. These fragmentation reactions depend on the type of betaine (X = NCH3 or S). For the negative dianionic clusters of tryptophan [Trp9-2H]2-, the important channel at low electron energies is loss of a neutral. Coulomb explosion competes from 19.8 eV and dominates at high electron energies. A small amount of [Trp2-H-NH3]- is observed at 21.8 eV.
Simulations of charge transfer in Electron Multiplying Charge Coupled Devices
NASA Astrophysics Data System (ADS)
Bush, N.; Stefanov, K.; Hall, D.; Jordan, D.; Holland, A.
2014-12-01
Electron Multiplying Charge Coupled Devices (EMCCDs) are a variant of traditional CCD technology well suited to applications that demand high speed operation in low light conditions. On-chip signal amplification allows the sensor to effectively suppress the noise introduced by readout electronics, permitting sub-electron read noise at MHz pixel rates. The devices have been the subject of many detailed studies concerning their operation, however there has not been a study into the transfer and multiplication process within the EMCCD gain register. Such an investigation has the potential to explain certain observed performance characteristics, as well as inform further optimisations to their operation. In this study, the results from simulation of charge transfer within an EMCCD gain register element are discussed with a specific focus on the implications for serial charge transfer efficiency (CTE). The effects of operating voltage and readout speed are explored in context with typical operating conditions. It is shown that during transfer, a small portion of signal charge may become trapped at the semiconductor-insulator interface that could act to degrade the serial CTE in certain operating conditions.
Proximity effects in cold gases of multiply charged atoms (Review)
NASA Astrophysics Data System (ADS)
Chikina, I.; Shikin, V.
2016-07-01
Possible proximity effects in gases of cold, multiply charged atoms are discussed. Here we deal with rarefied gases with densities nd of multiply charged (Z ≫ 1) atoms at low temperatures in the well-known Thomas-Fermi (TF) approximation, which can be used to evaluate the statistical properties of single atoms. In order to retain the advantages of the TF formalism, which is successful for symmetric problems, the external boundary conditions accounting for the finiteness of the density of atoms (donors), nd ≠ 0, are also symmetrized (using a spherical Wigner-Seitz cell) and formulated in a standard way that conserves the total charge within the cell. The model shows that at zero temperature in a rarefied gas of multiply charged atoms there is an effective long-range interaction Eproxi(nd), the sign of which depends on the properties of the outer shells of individual atoms. The long-range character of the interaction Eproxi is evaluated by comparing it with the properties of the well-known London dispersive attraction ELond(nd) < 0, which is regarded as a long-range interaction in gases. For the noble gases argon, krypton, and xenon Eproxi>0 and for the alkali and alkaline-earth elements Eproxi < 0. At finite temperatures, TF statistics manifests a new, anomalously large proximity effect, which reflects the tendency of electrons localized at Coulomb centers to escape into the continuum spectrum. The properties of thermal decay are interesting in themselves as they determine the important phenomenon of dissociation of neutral complexes into charged fragments. This phenomenon appears consistently in the TF theory through the temperature dependence of the different versions of Eproxi. The anomaly in the thermal proximity effect shows up in the following way: for T ≠ 0 there is no equilibrium solution of TS statistics for single multiply charged atoms in a vacuum when the effect is present. Instability is suppressed in a Wigner-Seitz model under the assumption that
Fabrication of an electron multiplier utilizing diamond films
NASA Technical Reports Server (NTRS)
Mearini, G. T.; Krainsky, I. L.; Wang, Y. X.; Dayton, JR., J. a.; Ramesham, R.; Rose, M. F.
1994-01-01
High secondary electron yields (sigma=14-27) from polycrystalline diamond films on Mo substrates have been reported previously. We observed that continuous exposure to an electron beam degraded the secondary yield in vacuum as a function of fluence owing to a loss of surface hydrogen. However, the hydrogen partial pressure could be adjusted such that the high secondary yield remained stable during beam exposure. We have constructed a prototype electron multiplier using these diamond films for use in ultrahigh vacuum. A gain of 0.9 times 10(exp 5) has been measured in a d.c. mode. Palladium, titanium and aluminum nitride have been studied for possible dynode substrate materials which might eliminate the need for hydrogen during operation. Total secondary yields as high as 50 were measured from diamond on palladium and sigma was stable at 25 during heating at 700 K in vacuum. Raman spectroscopy and scanning electron microscopy showed that variations in sigma from diamond films on Pd were due to differing concentrations of non-diamond carbon.
THz frequency multiplier chains base on planar Schottky diodes
NASA Technical Reports Server (NTRS)
Maiwald, F.; Schlecht, E.; Maestrini, A.; Chattopadhyay, G.; Pearson, J.; Pukala, D.; Mehdi, I.
2002-01-01
The Herschel Space Observatory (HSO), an ESA cornerstone mission with NASA contribution, will enable a comprehensive study of the galactic as well as the extra galactic universe. At the heart of this exploration are ultra sensitive coherent detectors that can allow for high-resolution spectroscopy. Successful operation of these receivers is predicated on providing a sufficiently powerful local oscillator (LO) source. Historically, a versatile space qualified LO source for frequencies beyond 500 GHz has been difficult if not impossible. This paper will focus on the effort under way to develop, build, characterize and qualify a LO chain to 1200 GHz (Band 5 on HSO) that is based on planar GaAs diodes mounted in waveguide circuits. State-of-the-art performance has been obtained from a three-stage ( x2 x 2 x 3 ) multiplier chain that can provide a peak output power of 120 uW (1178 GHz) at room temperature and a peak output power of 190 uW at 1183 GHz when cooled to 113 K. Implementation of this LO source for the Heterodyne Instrument for Far Infrared (HIFI) on HSO will be discussed in detail.
The "ups" and "downs" in Using Subtractive Cloning Techniques to Isolate Regulated Genes in Fish.
Goetz, Frederick William
2003-12-01
Over the last decade, subtractive cloning approaches have been used extensively to isolate genes that are up- or down-regulated under various conditions. These techniques have provided the foundation for many subsequent studies concerning gene function and regulation and, as such, have been valuable tools for many biological fields. Over the past 10 years, we have used different subtractive cloning approaches to isolate genes in fish that are regulated in relation to hormonal stimulation or the stage of ovarian maturation. These include conventional cDNA subtraction followed by library screening, differential display PCR, suppression subtraction hybridization, and more recently, iterative PCR subtraction. We continue to use these techniques for the isolation of new genes involved in physiological processes in fish and bivalve molluscs. Examples that illustrate the use of these different subtractive cloning techniques are described, including where possible the advantages and disadvantages of each. In addition, the use of ancillary methods (e.g., "Reverse Northerns") to facilitate the use of these subtractive approaches are discussed. PMID:21680477
Slaughter, Virginia; Kamppi, Dorian; Paynter, Jessica
2006-01-01
Two experiments were conducted to test the hypothesis that toddlers have access to an analog-magnitude number representation that supports numerical reasoning about relatively large numbers. Three-year-olds were presented with subtraction problems in which initial set size and proportions subtracted were systematically varied. Two sets of cookies were presented and then covered. The experimenter visibly subtracted cookies from the hidden sets, and the children were asked to choose which of the resulting sets had more. In Experiment 1, performance was above chance when high proportions of objects (3 versus 6) were subtracted from large sets (of 9) and for the subset of older participants (older than 3 years, 5 months; n = 15), performance was also above chance when high proportions (10 versus 20) were subtracted from the very large sets (of 30). In Experiment 2, which was conducted exclusively with older 3-year-olds and incorporated an important methodological control, the pattern of results for the subtraction tasks was replicated. In both experiments, success on the tasks was not related to counting ability. The results of these experiments support the hypothesis that young children have access to an analog-magnitude system for representing large approximate quantities, as performance on these subtraction tasks showed a Weber's Law signature, and was independent of conventional number knowledge.
ERIC Educational Resources Information Center
Robert, Nicole D.; LeFevre, Jo-Anne
2013-01-01
Does solving subtraction problems with negative answers (e.g., 5-14) require different cognitive processes than solving problems with positive answers (e.g., 14-5)? In a dual-task experiment, young adults (N=39) combined subtraction with two working memory tasks, verbal memory and visual-spatial memory. All of the subtraction problems required…
ERIC Educational Resources Information Center
Dixon, Juli K.; Andreasen, Janet B.; Avila, Cheryl L.; Bawatneh, Zyad; Deichert, Deana L.; Howse, Tashana D.; Turner, Mercedes Sotillo
2014-01-01
A goal of this study was to examine elementary preservice teachers' (PSTs) ability to contextualize and decontextualize fraction subtraction by asking them to write word problems to represent fraction subtraction expressions and to choose prewritten word problems to support given fraction subtraction expressions. Three themes emerged from the…
NASA Technical Reports Server (NTRS)
Klein, L. R.
1974-01-01
The free vibrations of elastic structures of arbitrary complexity were analyzed in terms of their component modes. The method was based upon the use of the normal unconstrained modes of the components in a Rayleigh-Ritz analysis. The continuity conditions were enforced by means of Lagrange Multipliers. Examples of the structures considered are: (1) beams with nonuniform properties; (2) airplane structures with high or low aspect ratio lifting surface components; (3) the oblique wing airplane; and (4) plate structures. The method was also applied to the analysis of modal damping of linear elastic structures. Convergence of the method versus the number of modes per component and/or the number of components is discussed and compared to more conventional approaches, ad-hoc methods, and experimental results.
Telencephalic embryonic subtractive sequences: a unique collection of neurodevelopmental genes.
Bulfone, Alessandro; Carotenuto, Pietro; Faedo, Andrea; Aglio, Veruska; Garzia, Livia; Bello, Anna Maria; Basile, Andrea; Andrè, Alessandra; Cocchia, Massimo; Guardiola, Ombretta; Ballabio, Andrea; Rubenstein, John L R; Zollo, Massimo
2005-08-17
The vertebrate telencephalon is composed of many architectonically and functionally distinct areas and structures, with billions of neurons that are precisely connected. This complexity is fine-tuned during development by numerous genes. To identify genes involved in the regulation of telencephalic development, a specific subset of differentially expressed genes was characterized. Here, we describe a set of cDNAs encoded by genes preferentially expressed during development of the mouse telencephalon that was identified through a functional genomics approach. Of 832 distinct transcripts found, 223 (27%) are known genes. Of the remaining, 228 (27%) correspond to expressed sequence tags of unknown function, 58 (7%) are homologs or orthologs of known genes, and 323 (39%) correspond to novel rare transcripts, including 48 (14%) new putative noncoding RNAs. As an example of this latter group of novel precursor transcripts of micro-RNAs, telencephalic embryonic subtractive sequence (TESS) 24.E3 was functionally characterized, and one of its targets was identified: the zinc finger transcription factor ZFP9. The TESS transcriptome has been annotated, mapped for chromosome loci, and arrayed for its gene expression profiles during neural development and differentiation (in Neuro2a and neural stem cells). Within this collection, 188 genes were also characterized on embryonic and postnatal tissue by in situ hybridization, demonstrating that most are specifically expressed in the embryonic CNS. The full information has been organized into a searchable database linked to other genomic resources, allowing easy access to those who are interested in the dissection of the molecular basis of telencephalic development.
The need of DNA computing: reversible designs of adders and multipliers using Fredkin gate
NASA Astrophysics Data System (ADS)
Thapliyal, Himanshu; Srinivas, M. B.
2005-12-01
In recent years, reversible logic has emerged as a promising computing paradigm having its applications in low power computing, quantum computing, nanotechnology, optical computing and DNA computing. The classical set of gates such as AND, OR, and EXOR are not reversible. Recently, it was shown how to encode information in DNA and use DNA amplification to implement Fredkin gates. Furthermore, in the past Fredkin gates have been constructed using DNA, whose outputs are used as inputs for other Fredkin gates. Thus, it can be concluded that arbitrary circuits of Fredkin gates can be constructed using DNA. This has been the driving force leading to the design of reversible adder and multipliers using Fredkin gate. The ripple carry and carry skip adders designed from Fredkin gates already exist in literature; the present work provides an comprehensive extension and novelty to the existing work by introducing the reversible carry look-ahead adder and reversible multipliers using Fredkin gate. The reversible multipliers designed using Fredkin gates are array multiplier, Baugh Wooley multiplier and Wallace tree multiplier. Since, reversible 4:2 compressors are required for the design of reversible Wallace tree multiplier; hence 4:2 compressor is also designed with Fredkin gates. The reversible circuits designed and proposed in this paper form the basis of the ALU of a primitive DNA CPU.
The Origins of the SPAR-H Method's Performance Shaping Factor Multipliers
Ronald L. Boring; Harold S. Blackman
2007-08-01
The Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H) method has proved to be a reliable, easy-to-use method for human reliability analysis. Calculation of human error probability (HEP) rates is especially straightforward, starting with pre-defined nominal error rates for cognitive vs. action oriented tasks, and incorporating performance shaping factor (PSF) multipliers upon those nominal error rates. SPAR-H uses eight PSFs with multipliers typically corresponding to nominal, degraded, and severely degraded human performance for individual PSFs. Additionally, some PSFs feature multipliers to reflect enhanced performance. Although SPAR-H enjoys widespread use among industry and regulators, current source documents on SPAR-H such as NUREG/CR-6883 do not provide a clear account of the origin of these multipliers. The present paper redresses this shortcoming and documents the historic development of the SPAR-H PSF multipliers, from the initial use of nominal error rates, to the selection of the eight PSFs, to the mapping of multipliers to available data sources such as a Technique for Human Error Rate Prediction (THERP). Where error rates were not readily derived from THERP and other sources, expert judgment was used to extrapolate appropriate values. In documenting key background information on the multipliers, this paper provides a much needed cross-reference for human reliability practitioners and researchers of SPAR-H to validate analyses and research findings.
Gas-Phase Dissociation Pathways of Multiply Charged Peptide Clusters
Jurchen, John C.; Garcia, David E.; Williams, Evan R.
2005-01-01
Numerous studies of cluster formation and dissociation have been conducted to determine properties of matter in the transition from the condensed phase to the gas phase using materials as diverse as atomic nuclei, noble gasses, metal clusters, and amino acids. Here, electrospray ionization is used to extend the study of cluster dissociation to peptides including leucine enkephalin with 7–19 monomer units and 2–5 protons, and somatostatin with 5 monomer units and 4 protons under conditions where its intramolecular disulfide bond is either oxidized or reduced. Evaporation of neutral monomers and charge separation by cluster fission are the competing dissociation pathways of both peptides. The dominant fission product for all leucine enkephalin clusters studied is a proton-bound dimer, presumably due to the high gas-phase stability of this species. The branching ratio of the fission and evaporation processes for leucine enkephalin clusters appears to be determined by the value of z2/n for the cluster where z is the charge and n the number of monomer units in the cluster. Clusters with low and high values of z2/n dissociate primarily by evaporation and cluster fission respectively, with a sharp transition between dissociation primarily by evaporation and primarily by fission measured at a z2/n value of ~0.5. The dependence of the dissociation pathway of a cluster on z2/n is similar to the dissociation of atomic nuclei and multiply charged metal clusters indicating that leucine enkephalin peptide clusters exist in a state that is more disordered, and possibly fluid, rather than highly structured in the dissociative transition state. The branching ratio, but not the dissociation pathway of [somatostatin5 + 4H]4+ is altered by the reduction of its internal disulfide bond indicating that monomer conformational flexibility plays a role in peptide cluster dissociation. PMID:14652186
Configurable multiplier modules for an adaptive computing system
NASA Astrophysics Data System (ADS)
Pfänder, O. A.; Pfleiderer, H.-J.; Lachowicz, S. W.
2006-09-01
The importance of reconfigurable hardware is increasing steadily. For example, the primary approach of using adaptive systems based on programmable gate arrays and configurable routing resources has gone mainstream and high-performance programmable logic devices are rivaling traditional application-specific hardwired integrated circuits. Also, the idea of moving from the 2-D domain into a 3-D design which stacks several active layers above each other is gaining momentum in research and industry, to cope with the demand for smaller devices with a higher scale of integration. However, optimized arithmetic blocks in course-grain reconfigurable arrays as well as field-programmable architectures still play an important role. In countless digital systems and signal processing applications, the multiplication is one of the critical challenges, where in many cases a trade-off between area usage and data throughput has to be made. But the a priori choice of word-length and number representation can also be replaced by a dynamic choice at run-time, in order to improve flexibility, area efficiency and the level of parallelism in computation. In this contribution, we look at an adaptive computing system called 3-D-SoftChip to point out what parameters are crucial to implement flexible multiplier blocks into optimized elements for accelerated processing. The 3-D-SoftChip architecture uses a novel approach to 3-dimensional integration based on flip-chip bonding with indium bumps. The modular construction, the introduction of interfaces to realize the exchange of intermediate data, and the reconfigurable sign handling approach will be explained, as well as a beneficial way to handle and distribute the numerous required control signals.
Laitila, Jussi; Moilanen, Atte; Pouzols, Federico M
2014-01-01
Biodiversity offsetting, which means compensation for ecological and environmental damage caused by development activity, has recently been gaining strong political support around the world. One common criticism levelled at offsets is that they exchange certain and almost immediate losses for uncertain future gains. In the case of restoration offsets, gains may be realized after a time delay of decades, and with considerable uncertainty. Here we focus on offset multipliers, which are ratios between damaged and compensated amounts (areas) of biodiversity. Multipliers have the attraction of being an easily understandable way of deciding the amount of offsetting needed. On the other hand, exact values of multipliers are very difficult to compute in practice if at all possible. We introduce a mathematical method for deriving minimum levels for offset multipliers under the assumption that offsetting gains must compensate for the losses (no net loss offsetting). We calculate absolute minimum multipliers that arise from time discounting and delayed emergence of offsetting gains for a one-dimensional measure of biodiversity. Despite the highly simplified model, we show that even the absolute minimum multipliers may easily be quite large, in the order of dozens, and theoretically arbitrarily large, contradicting the relatively low multipliers found in literature and in practice. While our results inform policy makers about realistic minimal offsetting requirements, they also challenge many current policies and show the importance of rigorous models for computing (minimum) offset multipliers. The strength of the presented method is that it requires minimal underlying information. We include a supplementary spreadsheet tool for calculating multipliers to facilitate application. PMID:25821578
2015-01-01
This study introduces a flexible and compound targeted approach to Deplete and Enrich Select Ingredients to Generate Normalized Extract Resources, generating DESIGNER extracts, by means of chemical subtraction or augmentation of metabolites. Targeting metabolites based on their liquid–liquid partition coefficients (K values), K targeting uses countercurrent separation methodology to remove single or multiple compounds from a chemically complex mixture, according to the following equation: DESIGNER extract = total extract ± target compound(s). Expanding the scope of the recently reported depletion of extracts by immunoaffinity or solid phase liquid chromatography, the present approach allows a more flexible, single- or multi-targeted removal of constituents from complex extracts such as botanicals. Chemical subtraction enables both chemical and biological characterization, including detection of synergism/antagonism by both the subtracted targets and the remaining metabolite mixture, as well as definition of the residual complexity of all fractions. The feasibility of the DESIGNER concept is shown by K-targeted subtraction of four bioactive prenylated phenols, isoxanthohumol (1), 8-prenylnaringenin (2), 6-prenylnaringenin (3), and xanthohumol (4), from a standardized hops (Humulus lupulus L.) extract using specific solvent systems. Conversely, adding K-targeted isolates allows enrichment of the original extract and hence provides an augmented DESIGNER material. Multiple countercurrent separation steps were used to purify each of the four compounds, and four DESIGNER extracts with varying depletions were prepared. The DESIGNER approach innovates the characterization of chemically complex extracts through integration of enabling technologies such as countercurrent separation, K-by-bioactivity, the residual complexity concepts, as well as quantitative analysis by 1H NMR, LC-MS, and HiFSA-based NMR fingerprinting. PMID:25437744
Hu, E; Lasio, G; Yi, B
2014-06-01
Purpose: The Iterative Subtraction Algorithm (ISA) method generates retrospectively a pre-selected motion phase cone-beam CT image from the full motion cone-beam CT acquired at standard rotation speed. This work evaluates ISA method with real lung patient data. Methods: The goal of the ISA algorithm is to extract motion and no- motion components form the full reconstruction CBCT. The workflow consists of subtracting from the full CBCT all of the undesired motion phases and obtain a motion de-blurred single-phase CBCT image, followed by iteration of this subtraction process. ISA is realized as follows: 1) The projections are sorted to various phases, and from all phases, a full reconstruction is performed to generate an image CTM. 2) Generate forward projections of CTM at the desired phase projection angles, the subtraction of projection and the forward projection will reconstruct a CTSub1, which diminishes the desired phase component. 3) By adding back the CTSub1 to CTm, no motion CBCT, CTS1, can be computed. 4) CTS1 still contains residual motion component. 5) This residual motion component can be further reduced by iteration.The ISA 4DCBCT technique was implemented using Varian Trilogy accelerator OBI system. To evaluate the method, a lung patient CBCT dataset was used. The reconstruction algorithm is FDK. Results: The single phase CBCT reconstruction generated via ISA successfully isolates the desired motion phase from the full motion CBCT, effectively reducing motion blur. It also shows improved image quality, with reduced streak artifacts with respect to the reconstructions from unprocessed phase-sorted projections only. Conclusion: A CBCT motion de-blurring algorithm, ISA, has been developed and evaluated with lung patient data. The algorithm allows improved visualization of a single phase motion extracted from a standard CBCT dataset. This study has been supported by National Institute of Health through R01CA133539.
Spectral subtraction-based speech enhancement for cochlear implant patients in background noise
NASA Astrophysics Data System (ADS)
Yang, Li-Ping; Fu, Qian-Jie
2005-03-01
A single-channel speech enhancement algorithm utilizing speech pause detection and nonlinear spectral subtraction is proposed for cochlear implant patients in the present study. The spectral subtraction algorithm estimates the short-time spectral magnitude of speech by subtracting the estimated noise spectral magnitude from the noisy speech spectral magnitude. The artifacts produced by spectral subtraction (such as ``musical noise'') were significantly reduced by combining variance-reduced gain function and spectral flooring. Sentence recognition by seven cochlear implant subjects was tested under different noisy listening conditions (speech-shaped noise and 6-talker speech babble at +9, +6, +3, and 0 dB SNR) with and without the speech enhancement algorithm. For speech-shaped noise, performance for all subjects at all SNRs was significantly improved by the speech enhancement algorithm; for speech babble, performance was only modestly improved. The results suggest that the proposed speech enhancement algorithm may be beneficial for implant users in noisy listening. .
NASA Astrophysics Data System (ADS)
Jutamulia, Suganda; Storti, George M.; Seiderman, William; Lindmayer, Joseph; Gregory, Don A.
1993-02-01
The application of electron trapping (ET) materials to parallel incoherent image subtraction over a wide dynamic range is examined in detail. A new incoherent image-subtraction technique based on ET materials is presented which can be applied to automation for microcircuit manufacture and inspection and potentially to data compression for videophones, teleconferencing, and high-definition TV. It is suggested that a high-quality ET thin-film could be coupled directly with a CCD chip to perform real-time image subtraction between two simultaneous scenes or subsequent frames. The advantages of the ET-based technique over the incoherent image-subtraction technique based on two liquid-crystal light valves include absence of coherent noise, high resolution, high space-bandwidth product, high speed, and cost effectiveness.
NASA Technical Reports Server (NTRS)
Clauson, J.; Heuser, J.
1981-01-01
The Applications Data Service (ADS) is a system based on an electronic data communications network which will permit scientists to share the data stored in data bases at universities and at government and private installations. It is designed to allow users to readily locate and access high quality, timely data from multiple sources. The ADS Pilot program objectives and the current plans for accomplishing those objectives are described.
Koster, K.; Wackers, F.J.; Mattera, J.A.; Fetterman, R.C. )
1990-08-01
Standard interpolative background subtraction, as used for thallium-201 ({sup 201}Tl), may create artifacts when applied to planar technetium-99m-Sestamibi ({sup 99m}Tc-Sestamibi) images, apparently because of the oversubtraction of relatively high extra-cardiac activity. A modified background subtraction algorithm was developed and compared to standard background subtraction in 16 patients who had both exercise-delayed {sup 201}Tl and exercise-rest {sup 99m}Tc-Sestamibi imaging. Furthermore, a new normal data base was generated. Normal {sup 99m}Tc-Sestamibi distribution was slightly different compared to {sup 201}Tl. Using standard background subtraction, mean defect reversibility was significantly underestimated by {sup 99m}Tc-Sestamibi compared to {sup 201}Tl (2.8 +/- 4.9 versus -1.8 +/- 8.4, p less than 0.05). Using the modified background subtraction, mean defect reversibility on {sup 201}Tl and {sup 99m}Tc-Sestamibi images was comparable (2.8 +/- 4.9 versus 1.7 +/- 5.2, p = NS). We conclude, that for quantification of {sup 99m}Tc-Sestamibi images a new normal data base, as well as a modification of the interpolative background subtraction method should be employed to obtain quantitative results comparable to those with {sup 201}Tl.
Value of blood-pool subtraction in cardiac indium-111-labeled platelet imaging
Machac, J.; Vallabhajosula, S.; Goldman, M.E.; Goldsmith, S.J.; Palestro, C.; Strashun, A.; Vaquer, R.; Phillips, R.A.; Fuster, V. )
1989-09-01
Blood-pool subtraction has been proposed to enhance {sup 111}In-labeled platelet imaging of intracardiac thrombi. We tested the accuracy of labeled platelet imaging, with and without blood-pool subtraction, in ten subjects with cardiac thrombi of varying age, eight with endocarditis being treated with antimicrobial therapy and ten normal controls. Imaging was performed early after labeled platelet injection (24 hr or less) and late (48 hr or more). Blood-pool subtraction was carried out. All images were graded subjectively by four experienced, blinded readers. Detection accuracy was measured by the sensitivity at three fixed levels of specificity estimated from receiver operator characteristic curve analysis and tested by three-way analysis of variance. Detection accuracy was generally improved on delayed images. Blood-pool subtraction did not improve accuracy. Although blood-pool subtraction increased detection sensitivity, this was offset by decreased specificity. For this population studied, blood-pool subtraction did not improve subjective detection of abnormal platelet deposition by 111In platelet imaging.
Young children's use of derived fact strategies for addition and subtraction
Dowker, Ann
2014-01-01
Forty-four children between 6;0 and 7;11 took part in a study of derived fact strategy use. They were assigned to addition and subtraction levels on the basis of calculation pretests. They were then given Dowker's (1998) test of derived fact strategies in addition, involving strategies based on the Identity, Commutativity, Addend +1, Addend −1, and addition/subtraction Inverse principles; and test of derived fact strategies in subtraction, involving strategies based on the Identity, Minuend +1, Minuend −1, Subtrahend +1, Subtrahend −1, Complement and addition/subtraction Inverse principles. The exact arithmetic problems given varied according to the child's previously assessed calculation level and were selected to be just a little too difficult for the child to solve unaided. Children were given the answer to a problem and then asked to solve another problem that could be solved quickly by using this answer, together with the principle being assessed. The children also took the WISC Arithmetic subtest. Strategies differed greatly in difficulty, with Identity being the easiest, and the Inverse and Complement principles being most difficult. The Subtrahend +1 and Subtrahend −1 problems often elicited incorrect strategies based on an overextension of the principles of addition to subtraction. It was concluded that children may have difficulty with understanding and applying the relationships between addition and subtraction. Derived fact strategy use was significantly related to both calculation level and to WISC Arithmetic scaled score. PMID:24431996
Doubles counting of highly multiplying items in reflective surroundings
Croft, Stephen; Evans, Louise G; Schear, Melissa A; Tobin, Stephen J
2010-11-18
When a neutrons are counted from a spontaneously fissile multiplying item in a reflecting environment the temporal behavior of the correlated signal following neutron birth is complex. At early times the signal is dominated by prompt fission events coming from spontaneous fission bursts and also from prompt fast-neutron induced fission events. At later times neutrons 'returning' from the surroundings induce fission and give rise to an additional chain of correlated events. The prompt and returning components probe the fissile and fertile constituents of the item in different ways and it is potentially beneficial to exploit this fact. In this work we look at how the two components can be represented using a linear combination of two simple functions. Fitting of the composite function to the capture time distribution represents one way of quantifying the proportion of each contribution. Another approach however is to use a dual shift register analysis where after each triggering event two coincidence gates are opened, one close to the trigger that responds preferentially to the prompt dynamics and one later in time which is more sensitive to the returning neutron induced events. To decide on the best gate positions and gate widths and also to estimate the counting precision we can use the analytical fit to work out the necessary gate utilization factors which are required in both these calculations. In this work, we develop the approach. Illustrative examples are given using spent Low Enriched Uranium (LEU) Pressurized light Water Reactor (LWR) fuel assemblies submersed in borated water and counted in a ring of {sup 3}He gas-filled proportional counters. In this case the prompt component is dominated by {sup 244}Cm spontaneous fission and induced fast neutron fission in for example {sup 238}U while the returning low energy neutrons induce fission mainly in the fissile nuclides such as {sup 239}Pu, {sup 241}Pu and {sup 235}U. One requirement is to calculate the Random
NASA Astrophysics Data System (ADS)
Stolper, D. A.; Martini, A. M.; Clog, M.; Douglas, P. M.; Shusta, S. S.; Valentine, D. L.; Sessions, A. L.; Eiler, J. M.
2015-07-01
Sources of methane to sedimentary environments are commonly identified and quantified using the stable isotopic compositions of methane. The methane "clumped-isotope geothermometer", based on the measurement of multiply substituted methane isotopologues (13CH3D and 12CH2D2), shows promise in adding new constraints to the sources and formational environments of both biogenic and thermogenic methane. However, questions remain about how this geothermometer behaves in systems with mixtures of biogenic and thermogenic gases and different biogenic environments. We have applied the methane clumped-isotope thermometer to a mixed biogenic-thermogenic system (Antrim Shale, USA) and to biogenic gas from gas seeps (Santa Barbara and Santa Monica Basin, USA), a pond on the Caltech campus, and methanogens grown in pure culture. We demonstrate that clumped-isotope based temperatures add new quantitative constraints to the relative amounts of biogenic vs. thermogenic gases in the Antrim Shale indicating a larger proportion (∼50%) of thermogenic gas in the system than previously thought. Additionally, we find that the clumped-isotope temperature of biogenic methane appears related to the environmental settings in which the gas forms. In systems where methane generation rates appear to be slow (e.g., the Antrim Shale and gas seeps), microbial methane forms in or near both internal isotopic equilibrium and hydrogen-isotope equilibrium with environmental waters. In systems where methane forms rapidly, microbial methane is neither in internal isotopic equilibrium nor hydrogen-isotope equilibrium with environmental waters. A quantitative model of microbial methanogenesis that incorporates isotopes is proposed to explain these results.
A 260-340 GHz Dual Chip Frequency Tripler for THz Frequency Multiplier Chains
NASA Technical Reports Server (NTRS)
Maestrini, Alain; Tripon-Canseliet, Charlotte; Ward, John S.; Gill, John J.; Mehdi, Imran
2006-01-01
We designed and fabricated a fix-tuned balanced frequency tripler working in the 260-340 GHz band to be the first stage of a x3x3x3 multiplier chain to 2.7 THz. The design of a dual-chip version of this multiplier featuring an input splitter / output combiner as part of the input / output matching networks of both chips - with no degradation of the expected bandwidth and efficiency- will be presented.
ERIC Educational Resources Information Center
Richards, Andrew
2015-01-01
Two quantitative measures of school performance are currently used, the average points score (APS) at Key Stage 2 and value-added (VA), which measures the rate of academic improvement between Key Stage 1 and 2. These figures are used by parents and the Office for Standards in Education to make judgements and comparisons. However, simple…
NASA Astrophysics Data System (ADS)
Hall, David J.; Tutt, James H.; Soman, Matthew R.; Holland, Andrew D.; Murray, Neil J.; Schmitt, Bernd; Schmitt, Thorsten
2013-09-01
The Electron-Multiplying Charge-Coupled Device (EM-CCD) shares a similar structure to the CCD except for the inclusion of a gain register that multiplies signal before the addition of read-noise, offering sub-electron effective readnoise at high frame-rates. EM-CCDs were proposed for the dispersive spectrometer on the International X-ray Observatory (IXO) to bring sub-300 eV X-rays above the noise, increasing the science yield. The high-speed, low-noise performance of the EMCCD brought added advantages of reduced dark current and stray-light per frame, reducing cooling and filtering requirements. To increase grating efficiency, several diffracted spectral orders were co-located so the inherent energy resolution of the detector was required for order separation. Although the spectral resolution of the EM-CCD is degraded by the gain process, it was shown that the EM-CCD could achieve the required separation. The RIXS spectrometer at the Advanced Resonant Spectroscopy beamline (ADRESS) of the Swiss Light Source (SLS) at the Paul Scherrer Institute currently uses a CCD, with charge spreading between pixels limiting the spatial resolution to 24 μm (FWHM). Through improving the spatial resolution below 5 μm alongside upgrading the grating, a factor of two energy resolution improvement could theoretically be made. With the high-speed, low-noise performance of the EM-CCD, photon-counting modes could allow the use of centroiding techniques to improve the resolution. Using various centroiding techniques, a spatial resolution of 2 μm (FWHM) has been achieved experimentally, demonstrating the benefits of this detector technology for soft X-ray spectrometry. This paper summarises the use of EM-CCDs from our first investigations for IXO through to our latest developments in ground-based testing for synchrotron-research and looks beyond to future possibilities.
NASA Astrophysics Data System (ADS)
Accomazzi, Alberto; Henneken, E.; Grant, C. S.; Kurtz, M. J.; Di Milia, G.; Luker, J.; Thompson, D. M.; Bohlen, E.; Murray, S. S.
2011-05-01
ADS Labs is a platform that ADS is introducing in order to test and receive feedback from the community on new technologies and prototype services. Currently, ADS Labs features a new interface for abstract searches, faceted filtering of results, visualization of co-authorship networks, article-level recommendations, and a full-text search service. The streamlined abstract search interface provides a simple, one-box search with options for ranking results based on a paper relevancy, freshness, number of citations, and downloads. In addition, it provides advanced rankings based on collaborative filtering techniques. The faceted filtering interface allows users to narrow search results based on a particular property or set of properties ("facets"), allowing users to manage large lists and explore the relationship between them. For any set or sub-set of records, the co-authorship network can be visualized in an interactive way, offering a view of the distribution of contributors and their inter-relationships. This provides an immediate way to detect groups and collaborations involved in a particular research field. For a majority of papers in Astronomy, our new interface will provide a list of related articles of potential interest. The recommendations are based on a number of factors, including text similarity, citations, and co-readership information. The new full-text search interface allows users to find all instances of particular words or phrases in the body of the articles in our full-text archive. This includes all of the scanned literature in ADS as well as a select portion of the current astronomical literature, including ApJ, ApJS, AJ, MNRAS, PASP, A&A, and soon additional content from Springer journals. Fulltext search results include a list of the matching papers as well as a list of "snippets" of text highlighting the context in which the search terms were found. ADS Labs is available at http://adslabs.org
An investigation of self-subtraction holography in LiNbO3
NASA Technical Reports Server (NTRS)
Vahey, D. W.; Kenan, R. P.; Hartman, N. F.; Sherman, R. C.
1981-01-01
A sample having self subtraction characteristics that were very promising was tested in depth: hologram formation times were on the order of 150 sec, the null signal was less than 2.5% of the peak signal, and no fatigue nor instability was detected over the span of the experiments. Another sample, fabricated with, at most, slight modifications did not perform nearly as well. In all samples, attempts to improve self subtraction characteristics by various thermal treatments had no effects or adverse effects, with one exception in which improvement was noted after a time delay of several days. A theory developed to describe self subtraction showed the observed decrease in beam intensity with time, but the shape of the predicted decay curve was oscillatory in contrast to the exponential like decay observed. The theory was also inadequate to account for the experimental sensitivity of self subtraction to the Bragg angle of the hologram. It is concluded that self subtraction is a viable method for optical processing systems requiring background discrimination.
A two-step strategy for constructing specifically self-subtracted cDNA libraries
Laveder, Paolo; De Pittà, Cristiano; Toppo, Stefano; Valle, Giorgio; Lanfranchi, Gerolamo
2002-01-01
We have developed a new strategy for producing subtracted cDNA libraries that is optimized for connective and epithelial tissues, where a few exceptionally abundant (super-prevalent) RNA species account for a large fraction of the total mRNA mass. Our method consists of a two-step subtraction of the most abundant mRNAs: the first step involves a novel use of oligo-directed RNase H digestion to lower the concentration of tissue-specific, super-prevalent RNAs. In the second step, a highly specific subtraction is achieved through hybridization with probes from a 3′-end ESTs collection. By applying this technique in skeletal muscle, we have constructed subtracted cDNA libraries that are effectively enriched for genes expressed at low levels. We further report on frequent premature termination of transcription in human muscle mitochondria and discuss the importance of this phenomenon in designing subtractive approaches. The tissue-specific collections of cDNA clones generated by our method are particularly well suited for expression profiling. PMID:11972353
NASA Astrophysics Data System (ADS)
Cho, Jaeyoun; Krishnamurthy, Ashok
2003-10-01
Speech enhancement is an important problem with applications in hearing aid design, speech recognition, speech coding, etc. Parametric spectral subtraction is a common method for speech enhancement when only a single channel of data is available. On the other hand, beamforming methods can be used when multiple channels of spatially separated data are available, such as from a microphone array. In previous work, we have shown that spectral subtraction combined with spatial averaging from multiple microphones leads to improvements in speech SNR and reduction of musical noise compared with either method used alone. In this talk, we extend the previous work to combine parametric spectral subtraction with adaptive beamforming, specifically the generalized sidelobe canceller. The proposed parametric spectral subtraction method determines the parameters adaptively so as to minimize speech distortion. In addition, it is shown that the major drawback of spectral subtraction, so-called musical noise, can be diminished by adaptive beamforming process. We show that the method leads to a reduction of musical noise and results in the enhanced speech having better quality and intelligibility.
NASA Astrophysics Data System (ADS)
Hara, Takeshi; Mori, Shintaro; Kaneda, Takashi; Hayashi, Tatsuro; Katsumata, Akitoshi; Fujita, Hiroshi
2011-03-01
Inflammation in the paranasal sinus is often observed in seasonal allergic rhinitis or with colds, but is also an indication for odontogenic tumors, carcinoma of the maxillary sinus or a maxillary cyst. The detection of those findings in dental panoramic radiographs is not difficult for radiologists, but general dentists may miss the findings since they focus on treatments of teeth. The purpose of this work is to develop a contralateral subtraction method for detecting the odontogenic sinusitis region on dental panoramic radiographs. We developed a contralateral subtraction technique in paranasal sinus region, consisting of 1) image filtering of the smoothing and sobel operation for noise reduction and edge extraction, 2) image registration of mirrored image by using mutual information, and 3) image display method of subtracted pixel data. We employed 56 cases (24 normal and 32 abnormal). The abnormal regions and the normal cases were verified by a board-certified radiologist using CT scans. Observer studies with and without subtraction images were performed for 9 readers. The true-positive rate at a 50% confidence level in 7 out of 9 readers was improved, but there was no statistical significance in the difference of area-under-curve (AUC) in each radiologist. In conclusion, the contralateral subtraction images of dental panoramic radiographs may improve the detection rate of abnormal regions in paranasal sinus.
Prado, Jérôme; Mutreja, Rachna; Zhang, Hongchuan; Mehta, Rucha; Desroches, Amy S; Minas, Jennifer E; Booth, James R
2011-11-01
It has been proposed that recent cultural inventions such as symbolic arithmetic recycle evolutionary older neural mechanisms. A central assumption of this hypothesis is that the degree to which a preexisting mechanism is recycled depends on the degree of similarity between its initial function and the novel task. To test this assumption, we investigated whether the brain region involved in magnitude comparison in the intraparietal sulcus (IPS), localized by a numerosity comparison task, is recruited to a greater degree by arithmetic problems that involve number comparison (single-digit subtractions) than by problems that involve retrieving number facts from memory (single-digit multiplications). Our results confirmed that subtractions are associated with greater activity in the IPS than multiplications, whereas multiplications elicit greater activity than subtractions in regions involved in verbal processing including the middle temporal gyrus (MTG) and inferior frontal gyrus (IFG) that were localized by a phonological processing task. Pattern analyses further indicated that the neural mechanisms more active for subtraction than multiplication in the IPS overlap with those involved in numerosity comparison and that the strength of this overlap predicts interindividual performance in the subtraction task. These findings provide novel evidence that elementary arithmetic relies on the cooption of evolutionary older neural circuits. PMID:21246667
Isolation of Rhizobium loti Strain-Specific DNA Sequences by Subtraction Hybridization
Bjourson, A. J.; Cooper, J. E.
1988-01-01
Mixed-phase (heterogeneous) and single-phase (homogeneous) DNA subtraction-hybridization methods were used to isolate specific DNA probes for closely related Rhizobium loti strains. In the heterogeneous method, DNA from the prospective probe strain was repeatedly hybridized to a mixture of DNA from cross-hybridizing strains (subtracter DNA) which was immobilized on an epoxy-activated cellulose matrix. Probe strain sequences which shared homology with the matrix-bound subtracter DNA hybridized to it, leaving unique probe strain sequences in the mobile phase. In the homogeneous method, probe strain sequences were hybridized in solution to biotinylated, mercurated subtracter DNA. Biotinylated, mercurated subtracer DNA and probe strain sequences hybridized to it were removed by two-step affinity chromatography on streptavidin-agarose and thiol-Sepharose. The specificity of the sequences remaining after subtraction hybridization by both methods was assessed and compared by colony hybridization with R. loti strains. Both methods allowed the rapid isolation of strain-specific DNA fragments which were suitable for use as probes. Images PMID:16347782
Segmentation and quantification for Alzheimer's disease (AD): a preliminary study
NASA Astrophysics Data System (ADS)
Lei, Tianhu; Udupa, Jayaram K.; Zhuge, Ying; Moonis, Gul; Clark, Christopher
2003-05-01
Alzheimer's is a progressive brain disease and is clinically characterized by cognitive symptoms that, in combination with behavioral disturbances, significantly interfere with activities of daily living. The purpose of this study is to investigate the possibility of developing volumetric measures of the structural damage and atrophy of brain derived from multiprotocol MR imaging. Our approach first applies intensity inhomogeneity correction and intensity standardization to PD and T2 weighted MR images to create base images for quantitative image analysis. Then, vectorial scale-based fuzzy connectedness segmentation (VSFCS) and morphological operations are applied to the base images to extract masks of cerebrospinal fluid (CSF), grey matter (GM), and white matter (WM), and further to create a clean and accurate intracranial (IC) mask. After separating CSF from brain parenchyma (BP), VSFCS is applied to BP (PD and T2) images to generate pure GM and WM masks, and then subtracting these pure from the BP mask to detect AD lesions. This method was applied to a set of conventional PD and T2 weighted MR images that were obtained from 5 patients with probable AD and 5 healthy normal control subjects. The segmented images of individual brain tissue regions (CSF, GM, WM, and AD lesion) are consistent with a Neuroradiologist's examination. The quantitative analysis shows that patients with AD have more atrophy. The mean value of the volume of brain parenchyma of patients with AD is about 10% less than that of healthy controls.
Soares, Marcelo Bento; de Fatima Bonaldo, Maria; Hackett, Jeremiah D; Bhattacharya, Debashish
2009-01-01
Expressed Sequence Tags (ESTs) provide a rapid and efficient approach for gene discovery and analysis of gene expression in eukaryotes. ESTs have also become particularly important with recent expanded efforts in complete genome sequencing of understudied, nonmodel eukaryotes such as protists and algae. For these projects, ESTs provide an invaluable source of data for gene identification and prediction of exon-intron boundaries. The generation of EST data, although straightforward in concept, requires nonetheless great care to ensure the highest efficiency and return for the investment in time and funds. To this end, key steps in the process include generation of a normalized cDNA library to facilitate a high gene discovery rate followed by serial subtraction of normalized libraries to maintain the discovery rate. Here we describe in detail, protocols for normalization and subtraction of cDNA libraries followed by an example using the toxic dinoflagellate Alexandrium tamarense.
Titanium plate artefact mimicking popliteal artery dissection on digital subtraction CT angiography.
Woodacre, Timothy; Wienand-Barnett, Sophie
2013-04-05
Titanium plates used for the internal fixation of long bone fractures cause significant artefact on CT scans but have not been reported to affect digital subtraction CT angiography. We present a patient with clinical suspicion of popliteal artery injury following a high tibial osteotomy. The osteotomy was stabilised with a titanium locking plate. During the digital subtraction process used to produce reconstruction CT angiography, removal of artefact caused by the titanium plate produced CT images mimicking the appearance of a popliteal artery dissection. The imaging inaccuracy was realised prior to the patient undergoing further intervention. We highlight the potential error caused by titanium plates on digital subtraction CT angiography and recommend careful analysis of such images prior to further treatment.
[The backgroud sky subtraction around [OIII] line in LAMOST QSO spectra].
Shi, Zhi-Xin; Comte, Georges; Luo, A-Li; Tu, Liang-Ping; Zhao, Yong-Heng; Wu, Fu-Chao
2014-11-01
At present, most sky-subtraction methods focus on the full spectrum, not the particular location, especially for the backgroud sky around [OIII] line which is very important to low redshift quasars. A new method to precisely subtract sky lines in local region is proposed in the present paper, which sloves the problem that the width of Hβ-[OIII] line is effected by the backgroud sky subtraction. The exprimental results show that, for different redshift quasars, the spectral quality has been significantly improved using our method relative to the original batch program by LAMOST. It provides a complementary solution for the small part of LAMOST spectra which are not well handled by LAMOST 2D pipeline. Meanwhile, This method has been used in searching for candidates of double-peaked Active Galactic Nuclei.
A novel background subtraction technique based on grayscale morphology for weld defect detection
NASA Astrophysics Data System (ADS)
Aminzadeh, Masoumeh; Kurfess, Thomas
2016-04-01
Optical inspection is a non-destructive quality monitoring technique to detect defects in manufactured parts. Automating the defect detection, by application of image processing, prevents the presence of human operators making the inspection more reliable, reproducible and faster. In this paper, a background subtraction technique, based on morphological operations, is proposed. The low-computational load associated with the used morphological operations makes this technique more computationally effective than background subtraction techniques such as spline approximation and surface-fitting. The performance of the technique is tested by applying to detect defects in a weld seam with non-uniform intensity distribution where the defects are precisely segmented. The proposed background subtraction technique is generalizable to sheet, surface, or part defect detection in various applications of manufacturing.
Lee, Su-Yong; Kim, Ho-Joon; Ji, Se-Wan; Nha, Hyunchul
2011-07-15
We investigate how the entanglement properties of a two-mode state can be improved by performing a coherent superposition operation ta+ra{sup {dagger}} of photon subtraction and addition, proposed by Lee and Nha [Phys. Rev. A 82, 053812 (2010)], on each mode. We show that the degree of entanglement, the Einstein-Podolsky-Rosen-type correlation, and the performance of quantum teleportation can be all enhanced for the output state when the coherent operation is applied to a two-mode squeezed state. The effects of the coherent operation are more prominent than those of the mere photon subtraction a and the addition a{sup {dagger}} particularly in the small-squeezing regime, whereas the optimal operation becomes the photon subtraction (case of r=0) in the large-squeezing regime.
FamNet: A Framework to Identify Multiplied Modules Driving Pathway Expansion in Plants.
Ruprecht, Colin; Mendrinna, Amelie; Tohge, Takayuki; Sampathkumar, Arun; Klie, Sebastian; Fernie, Alisdair R; Nikoloski, Zoran; Persson, Staffan; Mutwil, Marek
2016-03-01
Gene duplications generate new genes that can acquire similar but often diversified functions. Recent studies of gene coexpression networks have indicated that, not only genes, but also pathways can be multiplied and diversified to perform related functions in different parts of an organism. Identification of such diversified pathways, or modules, is needed to expand our knowledge of biological processes in plants and to understand how biological functions evolve. However, systematic explorations of modules remain scarce, and no user-friendly platform to identify them exists. We have established a statistical framework to identify modules and show that approximately one-third of the genes of a plant's genome participate in hundreds of multiplied modules. Using this framework as a basis, we implemented a platform that can explore and visualize multiplied modules in coexpression networks of eight plant species. To validate the usefulness of the platform, we identified and functionally characterized pollen- and root-specific cell wall modules that multiplied to confer tip growth in pollen tubes and root hairs, respectively. Furthermore, we identified multiplied modules involved in secondary metabolite synthesis and corroborated them by metabolite profiling of tobacco (Nicotiana tabacum) tissues. The interactive platform, referred to as FamNet, is available at http://www.gene2function.de/famnet.html. PMID:26754669
Ryumin, Pavel; Brown, Jeffery; Morris, Michael; Cramer, Rainer
2016-07-15
Liquid matrix-assisted laser desorption/ionization (MALDI) allows the generation of predominantly multiply charged ions in atmospheric pressure (AP) MALDI ion sources for mass spectrometry (MS) analysis. The charge state distribution of the generated ions and the efficiency of the ion source in generating such ions crucially depend on the desolvation regime of the MALDI plume after desorption in the AP-to-vacuum inlet. Both high temperature and a flow regime with increased residence time of the desorbed plume in the desolvation region promote the generation of multiply charged ions. Without such measures the application of an electric ion extraction field significantly increases the ion signal intensity of singly charged species while the detection of multiply charged species is less dependent on the extraction field. In general, optimization of high temperature application facilitates the predominant formation and detection of multiply charged compared to singly charged ion species. In this study an experimental set-up and optimization strategy is described for liquid AP-MALDI MS which improves the ionization efficiency of selected ion species up to 14 times. In combination with ion mobility separation, the method allows the detection of multiply charged peptide and protein ions for analyte solution concentrations as low as 2fmol/μL (0.5μL, i.e. 1fmol, deposited on the target) with very low sample consumption in the low nL-range. PMID:26827934
Modeling self-subtraction in angular differential imaging: Application to the HD 32297 debris disk
Esposito, Thomas M.; Fitzgerald, Michael P.; Graham, James R.; Kalas, Paul
2014-01-01
We present a new technique for forward-modeling self-subtraction of spatially extended emission in observations processed with angular differential imaging (ADI) algorithms. High-contrast direct imaging of circumstellar disks is limited by quasi-static speckle noise, and ADI is commonly used to suppress those speckles. However, the application of ADI can result in self-subtraction of the disk signal due to the disk's finite spatial extent. This signal attenuation varies with radial separation and biases measurements of the disk's surface brightness, thereby compromising inferences regarding the physical processes responsible for the dust distribution. To compensate for this attenuation, we forward model the disk structure and compute the form of the self-subtraction function at each separation. As a proof of concept, we apply our method to 1.6 and 2.2 μm Keck adaptive optics NIRC2 scattered-light observations of the HD 32297 debris disk reduced using a variant of the 'locally optimized combination of images' algorithm. We are able to recover disk surface brightness that was otherwise lost to self-subtraction and produce simplified models of the brightness distribution as it appears with and without self-subtraction. From the latter models, we extract radial profiles for the disk's brightness, width, midplane position, and color that are unbiased by self-subtraction. Our analysis of these measurements indicates a break in the brightness profile power law at r ≈ 110 AU and a disk width that increases with separation from the star. We also verify disk curvature that displaces the midplane by up to 30 AU toward the northwest relative to a straight fiducial midplane.
Effect of color coding and subtraction on the accuracy of contrast echocardiography
NASA Technical Reports Server (NTRS)
Pasquet, A.; Greenberg, N.; Brunken, R.; Thomas, J. D.; Marwick, T. H.
1999-01-01
BACKGROUND: Contrast echocardiography may be used to assess myocardial perfusion. However, gray scale assessment of myocardial contrast echocardiography (MCE) is difficult because of variations in regional backscatter intensity, difficulties in distinguishing varying shades of gray, and artifacts or attenuation. We sought to determine whether the assessment of rest myocardial perfusion by MCE could be improved with subtraction and color coding. METHODS AND RESULTS: MCE was performed in 31 patients with previous myocardial infarction with a 2nd generation agent (NC100100, Nycomed AS), using harmonic triggered or continuous imaging and gain settings were kept constant throughout the study. Digitized images were post processed by subtraction of baseline from contrast data and colorized to reflect the intensity of myocardial contrast. Gray scale MCE alone, MCE images combined with baseline and subtracted colorized images were scored independently using a 16 segment model. The presence and severity of myocardial contrast abnormalities were compared with perfusion defined by rest MIBI-SPECT. Segments that were not visualized by continuous (17%) or triggered imaging (14%) after color processing were excluded from further analysis. The specificity of gray scale MCE alone (56%) or MCE combined with baseline 2D (47%) was significantly enhanced by subtraction and color coding (76%, p<0.001) of triggered images. The accuracy of the gray scale approaches (respectively 52% and 47%) was increased to 70% (p<0.001). Similarly, for continuous images, the specificity of gray scale MCE with and without baseline comparison was 23% and 42% respectively, compared with 60% after post processing (p<0.001). The accuracy of colorized images (59%) was also significantly greater than gray scale MCE (43% and 29%, p<0.001). The sensitivity of MCE for both acquisitions was not altered by subtraction. CONCLUSION: Post-processing with subtraction and color coding significantly improves the accuracy
Comparison of subtracted venography and phase contrast in cerebral regions by utilizing 3DT1TFE
NASA Astrophysics Data System (ADS)
Heo, Yeong-Cheol; Cho, Jae-Hwan; Jang, Hyon-Chol; Lee, Chang-Hee; Kim, Jung-Su; Lee, Hae-Kag
2013-06-01
In this study, we evaluated the 3D venography images and the phase contrast images that were subtracted by using the images that had been obtained before and after utilizing the contrast medium with a 3D, segmented, T1-weighted gradient echo sequence (3DT1TFE) when performing a cerebral magnetic resonance imaging (MRI) examination with contrast medium. The study was carried out in 10 patients who under went a brain examination with a contrast medium by using the 3.0T MR System and 8-channel sensitivity encoding (SENSE) head coil. The 3DT1TFE images after the contrast medium had been used was subtracted from the 3DT1TFE images before the utilization. The subtracted images were re-formed to venography images by using maximum intensity projection (MIP) techniques; then, the re-formed images and 3D phase contrast (PC) venography were evaluated qualitative analysis. The qualitative analysis was done to confirm the reliability of the ratings of the observers via the ICC (intraclass correlation coefficient) and then to evaluate of the statistical significance via an independent T-test. The ICC test showed that 3D PC venography images and subtracted venography images had reliabilities of 0.677 and 0.734 on average, respectively, indicating good reliability of the ratings by the observers. Because the proximal superior sagittal sinus (SSS), the middle SSS, the confluence SSS, the vein of labbe, the internal cerebral vein, and the Vein of Galen represented p > 0.05 a the independent T-test, no statistically significant difference was observed between the two images. However, a significant difference was observed between the images regarding the straight sinus (p < 0.05). As such, the venography images subtracted from the straight sinus would be better, because the average of the straight sinus was higher in subtracted venography.
1-loop partition function in AdS 3/ CFT 2
NASA Astrophysics Data System (ADS)
Chen, Bin; Wu, Jie-qiang
2015-12-01
The 1-loop partition function of the handlebody solutions in the AdS3 gravity have been derived some years ago using the heat kernel techniques and the method of images. In the semiclassical limit, such partition function should correspond to the order O( c 0) part in the partition function of dual conformal field theory(CFT) on the boundary Riemann surface. The higher genus partition function could be computed by the multi-point functions in the Riemann sphere via sewing prescription. In the large central charge limit, the CFT is effectively free in the sense that to the leading order of c the multi-point function is further simplified to be a summation over the products of two-point functions of single-particle states. Correspondingly in the bulk, the graviton is freely propagating without interaction. Furthermore the product of the two-point functions may define the links, each of which is in one-to-one correspondence with the conjugacy class of the Schottky group of the Riemann surface. Moreover, the value of a link is determined by the multiplier of the element in the conjugacy class. This allows us to reproduce exactly the gravitational 1-loop partition function. The proof can be generalized to the higher spin gravity and its dual CFT.
Two Virasoro symmetries in stringy warped AdS3
NASA Astrophysics Data System (ADS)
Compère, Geoffrey; Guica, Monica; Rodriguez, Maria J.
2014-12-01
We study three-dimensional consistent truncations of type IIB supergravity which admit warped AdS3 solutions. These theories contain subsectors that have no bulk dynamics. We show that the symplectic form for these theories, when restricted to the non-dynamical subsectors, equals the symplectic form for pure Einstein gravity in AdS3. Consequently, for each consistent choice of boundary conditions in AdS3, we can define a consistent phase space in warped AdS3 with identical conserved charges. This way, we easily obtain a Virasoro × Virasoro asymptotic symmetry algebra in warped AdS3; two different types of Virasoro × Kač-Moody symmetries are also consistent alternatives.
NASA Astrophysics Data System (ADS)
Rais, Muhammad H.
2010-06-01
This paper presents Field Programmable Gate Array (FPGA) implementation of standard and truncated multipliers using Very High Speed Integrated Circuit Hardware Description Language (VHDL). Truncated multiplier is a good candidate for digital signal processing (DSP) applications such as finite impulse response (FIR) and discrete cosine transform (DCT). Remarkable reduction in FPGA resources, delay, and power can be achieved using truncated multipliers instead of standard parallel multipliers when the full precision of the standard multiplier is not required. The truncated multipliers show significant improvement as compared to standard multipliers. Results show that the anomaly in Spartan-3 AN average connection and maximum pin delay have been efficiently reduced in Virtex-4 device.
Using a digital signal processor as a data stream controller for digital subtraction angiography
Meng, J.D.; Katz, J.E.
1991-10-01
High speed, flexibility, and good arithmetic abilities make digital signal processors (DSP) a good choice as input/output controllers for real time applications. The DSP can be made to pre-process data in real time to reduce data volume, to open early windows on what is being acquired and to implement local servo loops. We present an example of a DSP as an input/output controller for a digital subtraction angiographic imaging system. The DSP pre-processes the raw data, reducing data volume by a factor of two, and is potentially capable of producing real-time subtracted images for immediate display.
Intensity Weighted Subtraction Microscopy Approach for Image Contrast and Resolution Enhancement
NASA Astrophysics Data System (ADS)
Korobchevskaya, Kseniya; Peres, Chiara; Li, Zhibin; Antipov, Alexei; Sheppard, Colin J. R.; Diaspro, Alberto; Bianchini, Paolo
2016-05-01
We propose and demonstrate a novel subtraction microscopy algorithm, exploiting fluorescence emission difference or switching laser mode and their derivatives for image enhancement. The key novelty of the proposed approach lies in the weighted subtraction coefficient, adjusted pixel-by-pixel with respect to the intensity distributions of initial images. This method produces significant resolution enhancement and minimizes image distortions. Our theoretical and experimental studies demonstrate that this approach can be applied to any optical microscopy techniques, including label free and non-linear methods, where common super-resolution techniques cannot be used.
Tian, Nian; Fu, Ling; Gu, Min
2015-01-01
We extend the subtractive imaging method to label-free second harmonic generation (SHG) microscopy to enhance the spatial resolution and contrast. This method is based on the intensity difference between two images obtained with circularly polarized Gaussian and doughnut-shaped beams, respectively. By characterizing the intensity and polarization distributions of the two focused beams, we verify the feasibility of the subtractive imaging method in polarization dependent SHG microscopy. The resolution and contrast enhancement in different biological samples is demonstrated. This work will open a new avenue for the applications of SHG microscopy in biomedical research. PMID:26364733
Intensity Weighted Subtraction Microscopy Approach for Image Contrast and Resolution Enhancement
Korobchevskaya, Kseniya; Peres, Chiara; Li, Zhibin; Antipov, Alexei; Sheppard, Colin J. R.; Diaspro, Alberto; Bianchini, Paolo
2016-01-01
We propose and demonstrate a novel subtraction microscopy algorithm, exploiting fluorescence emission difference or switching laser mode and their derivatives for image enhancement. The key novelty of the proposed approach lies in the weighted subtraction coefficient, adjusted pixel-by-pixel with respect to the intensity distributions of initial images. This method produces significant resolution enhancement and minimizes image distortions. Our theoretical and experimental studies demonstrate that this approach can be applied to any optical microscopy techniques, including label free and non-linear methods, where common super-resolution techniques cannot be used. PMID:27174367
Real-time optical image subtraction by a holographic shear lens
NASA Astrophysics Data System (ADS)
Rao, V. Venkateswara; Joenathan, C.; Sirohi, R. S.
1985-08-01
A new optical method of image subtraction by employing a holographic shear lens is proposed. The principle underlying this technique is that of optical interference between two sheared fields produced by the holographic shear lens (HSL). Two dissimilar inputs with some common characters are subtracted in real time while keeping the HSL at the Fourier plane of a well corrected lens. The difference is detectable only when zero fringe is obtained in the interferogram. Experimental verification is presented with the results. The basic advantages of this technique are the simplicity in aligning the input transparencies and the real time operation.
Sturgill, James F.; Isaacson, Jeffry S.
2015-01-01
Diverse types of local GABAergic interneurons shape the cortical representation of sensory information. Here we show how somatostatin-expressing interneurons (SOM cells) contribute to odor coding in mouse olfactory cortex. We find that odor-tuned SOM cells regulate principal cells through a purely subtractive operation that is independent of odor identity or intensity. This operation enhances the salience of odor-evoked activity without changing cortical odor tuning. SOM cells inhibit both principal cells and fast-spiking interneurons, indicating that subtractive inhibition reflects the interplay of multiple classes of interneurons. PMID:25751531
... time when they are challenged with writing and math exercises. Generally, children with the disorder exhibit poor handwriting and spelling skills, and difficulty with math functions, including adding, subtracting, multiplying, and dividing. An ...
Coherent Raman scattering with incoherent light for a multiply resonant mixture: Theory
NASA Astrophysics Data System (ADS)
Kirkwood, Jason C.; Ulness, Darin J.; Stimson, Michael J.; Albrecht, A. C.
1998-02-01
The theory for coherent Raman scattering (CRS) with broadband incoherent light is presented for a multiply resonant, multicomponent mixture of molecules that exhibits simultaneous multiple resonances with the frequencies of the driving fields. All possible pairwise hyperpolarizability contributions to the signal intensity are included in the theoretical treatment-(resonant-resonant, resonant-nonresonant, and nonresonant-nonresonant correlations between chromophores) and it is shown how the different types of correlations manifest themselves as differently behaved components of the signal intensity. The Raman resonances are modeled as Lorentzians in the frequency domain, as is the spectral density of the incoherent light. The analytic results for this multiply resonant mixture are presented and applied to a specific binary mixture. These analytic results will be used to recover frequencies and dephasing times in a series of experiments on multiply resonant mixtures.
4.8GHz CMOS Frequency Multiplier Using Subharmonic Pulse-Injection Locking for Spurious Suppression
NASA Astrophysics Data System (ADS)
Takano, Kyoya; Motoyoshi, Mizuki; Fujishima, Minoru
To realize low-power wireless transceivers, it is necessary to improve the performance of frequency synthesizers, which are typically frequency multipliers composed of a phase-locked loop (PLL). However, PLLs generally consume a large amount of power and occupy a large area. To improve the frequency multiplier, we propose a pulse-injection-locked frequency multiplier (PILFM), where a spurious signal is suppressed using a pulse input signal. An injection-locked oscillator (ILO) in a PILFM was fabricated by a 0.18µm 1P5M CMOS process. The core size is 10.8µm × 10.5µm. The power consumption of the ILO is 9.6µW at 250MHz, 255µW at 2.4GHz and 1.47mW at 4.8GHz. The phase noise is -105dBc/Hz at a 1MHz offset.
Gao, Zhe; Dong, Mei; Wang, Guizhen; Sheng, Pei; Wu, Zhiwei; Yang, Huimin; Zhang, Bin; Wang, Guofu; Wang, Jianguo; Qin, Yong
2015-07-27
To design highly efficient catalysts, new concepts for optimizing the metal-support interactions are desirable. Here we introduce a facile and general template approach assisted by atomic layer deposition (ALD), to fabricate a multiply confined Ni-based nanocatalyst. The Ni nanoparticles are not only confined in Al2 O3 nanotubes, but also embedded in the cavities of Al2 O3 interior wall. The cavities create more Ni-Al2 O3 interfacial sites, which facilitate hydrogenation reactions. The nanotubes inhibit the leaching and detachment of Ni nanoparticles. Compared with the Ni-based catalyst supported on the outer surface of Al2 O3 nanotubes, the multiply confined catalyst shows a striking improvement of catalytic activity and stability in hydrogenation reactions. Our ALD-assisted template method is general and can be extended for other multiply confined nanoreactors, which may have potential applications in many heterogeneous reactions.
Non-cross talk multi-channel photomultiplier using guided electron multipliers
Gomez, J.; Majewski, S.; Weisenberger, A.G.
1995-09-26
An improved multi-channel electron multiplier is provided that exhibits zero cross-talk and high rate operation. Resistive material input and output masks are employed to control divergence of electrons. Electron multiplication takes place in closed channels. Several embodiments are provided for these channels including a continuous resistive emissive multiplier and a discrete resistive multiplier with discrete dynode chains interspaced with resistive layers-masks. Both basic embodiments provide high gain multiplication of electrons without accumulating surface charges while containing electrons to their proper channels to eliminate cross-talk. The invention can be for example applied to improve the performance of ion mass spectrometers, positron emission tomography devices, in DNA sequencing and other beta radiography applications and in many applications in particle physics. 28 figs.
Non cross talk multi-channel photomultiplier using guided electron multipliers
Gomez, Javier; Majewski, Stanislaw; Weisenberger, Andrew G.
1995-01-01
An improved multi-channel electron multiplier is provided that exhibits zero cross-talk and high rate operation. Resistive material input and output masks are employed to control divergence of electrons. Electron multiplication takes place in closed channels. Several embodiments are provided for these channels including a continuous resistive emissive multiplier and a discrete resistive multiplier with discrete dynode chains interspaced with resistive layers-masks. Both basic embodiments provide high gain multiplication of electrons without accumulating surface charges while containing electrons to their proper channels to eliminate cross-talk. The invention can be for example applied to improve the performance of ion mass spectrometers, positron emission tomography devices, in DNA sequencing and other beta radiography applications and in many applications in particle physics.
Bogomolov multiplier, double class-preserving automorphisms, and modular invariants for orbifolds
Davydov, Alexei
2014-09-01
We describe the group Aut{sub br}¹(Z(G)) of braided tensor autoequivalences of the Drinfeld centre of a finite group G isomorphic to the identity functor (just as a functor). We prove that the semi-direct product Out{sub 2₋cl}(G)⋉B(G) of the group of double class preserving automorphisms and the Bogomolov multiplier of G is a subgroup of Aut{sub br}¹(Z(G)). An automorphism of G is double class preserving if it preserves conjugacy classes of pairs of commuting elements in G. The Bogomolov multiplier B(G) is the subgroup of its Schur multiplier H²(G, k{sup *}) of classes vanishing on abelian subgroups of G. We show that elements of Aut{sub br}¹(Z(G)) give rise to different realisations of the charge conjugation modular invariant for G-orbifolds of holomorphic conformal field theories.
Designing voltage multipliers with nanofluidic diodes immersed in aqueous salt solutions.
Ramirez, P; Gomez, V; Verdia-Baguena, C; Nasir, S; Ali, M; Ensinger, W; Mafe, S
2016-02-01
Membranes with nanofluidic diodes allow the selective control of molecules in physiological salt solutions at ambient temperature. The electrical coupling of the membranes with conventional electronic elements such as capacitors suggests opportunities for the external monitoring of sensors and actuators. We demonstrate experimentally and theoretically the voltage multiplier functionality of simple electrical networks composed of membranes with conical nanopores coupled to load capacitors. The robust operation of half and full wave voltage multipliers is achieved in a broad range of experimental conditions (single pore and multipore membranes, electrolyte concentrations, voltage amplitudes, and solid-state capacitances). The designed voltage multipliers operate in the liquid state and can be used in sensing devices because different electrical, optical, and chemical inputs are known to modulate the individual nanofluidic diode resistances in the electrical network.
Evans, Nick
2016-09-12
Essential facts Leading Change, Adding Value is NHS England's new nursing and midwifery framework. It is designed to build on Compassion in Practice (CiP), which was published 3 years ago and set out the 6Cs: compassion, care, commitment, courage, competence and communication. CiP established the values at the heart of nursing and midwifery, while the new framework sets out how staff can help transform the health and care sectors to meet the aims of the NHS England's Five Year Forward View. PMID:27615573
NASA Astrophysics Data System (ADS)
Wang, Weiguo; Zhao, Wuduo; Hua, Lei; Hou, Keyong; Li, Haiyang
2016-05-01
This paper investigated the dependence of multiply charged ions on the laser polarization state when benzene cluster was irradiated with 532 and 1064 nm nanosecond laser. A circle, square and flower distribution for C2+, C3+ and C4+ were observed with 532 nm laser respectively, while flower petals for C2+, C3+ and C4+ were observed at 1064 nm as the laser polarization varied. A theoretical calculation was performed to interpret the polarization state and wavelength dependence of the multiply charged ions. The simulated results agreed well with the experimental observation with considering the contribution from the cluster disintegration.
Eberhorn, A C; Büttner-Ennever, J A; Horn, A K E
2006-02-01
In mammals, the extraocular muscle fibers can be categorized in singly-innervated and multiply-innervated muscle fibers. In the monkey oculomotor, trochlear and abducens nucleus the motoneurons of multiply-innervated muscle fibers lie separated from those innervating singly-innervated muscle fibers and show different histochemical properties. In order to discover, if this organization is a general feature of the oculomotor system, we investigated the location of singly-innervated muscle fiber and multiply-innervated muscle fiber motoneurons in the rat using combined tract-tracing and immunohistochemical techniques. The singly-innervated muscle fiber and multiply-innervated muscle fiber motoneurons of the medial and lateral rectus muscle were identified by retrograde tracer injections into the muscle belly or the distal myotendinous junction. The belly injections labeled the medial rectus muscle subgroup of the oculomotor nucleus or the greatest part of abducens nucleus, including some cells outside the medial border of abducens nucleus. In contrast, the distal injections labeled only a subset of the medial rectus muscle motoneurons and exclusively cells outside the medial border of abducens nucleus. The tracer detection was combined with immunolabeling using antibodies for perineuronal nets (chondroitin sulfate proteoglycan) and non-phosphorylated neurofilaments. In monkeys both antibodies permit a distinction between singly-innervated muscle fiber and multiply-innervated muscle fiber motoneurons. The experiments revealed that neurons labeled from a distal injection lack both markers and are assumed to represent multiply-innervated muscle fiber motoneurons, whereas those labeled from a belly injection are chondroitin sulfate proteoglycan- and non-phosphorylated neurofilament-immunopositive and assumed to represent singly-innervated muscle fiber motoneurons. The overall identification of multiply-innervated muscle fiber and singly-innervated muscle fiber motoneurons
Theory of a stationary microwave discharge with multiply charged ions in an expanding gas jet
NASA Astrophysics Data System (ADS)
Shalashov, A. G.; Abramov, I. S.; Golubev, S. V.; Gospodchikov, E. D.
2016-08-01
The formation of a jet of a nonequilibrium multiply charged ion plasma is studied in the inhomogeneous gas jet. It is shown that the geometrical divergence of the jet restricts the maximum ion charge state and results in the spatial localization of the discharge. Stationary solutions corresponding to such regimes are constructed. The model proposed can be used to optimize modern experiments on generation of hard UV radiation due to the line emission of multiply ionized atoms in a gas jet heated by high-power millimeter and submillimeter radiation.
High frequency capacitor-diode voltage multiplier dc-dc converter development
NASA Technical Reports Server (NTRS)
Kisch, J. J.; Martinelli, R. M.
1977-01-01
A power conditioner was developed which used a capacitor diode voltage multiplier to provide a high voltage without the use of a step-up transformer. The power conditioner delivered 1200 Vdc at 100 watts and was operated from a 120 Vdc line. The efficiency was in excess of 90 percent. The component weight was 197 grams. A modified boost-add circuit was used for the regulation. A short circuit protection circuit was used which turns off the drive circuit upon a fault condition, and recovers within 5 ms after removal of the short. High energy density polysulfone capacitors and high speed diodes were used in the multiplier circuit.
Multiply scaled constrained nonlinear equation solvers. [for nonlinear heat conduction problems
NASA Technical Reports Server (NTRS)
Padovan, Joe; Krishna, Lala
1986-01-01
To improve the numerical stability of nonlinear equation solvers, a partitioned multiply scaled constraint scheme is developed. This scheme enables hierarchical levels of control for nonlinear equation solvers. To complement the procedure, partitioned convergence checks are established along with self-adaptive partitioning schemes. Overall, such procedures greatly enhance the numerical stability of the original solvers. To demonstrate and motivate the development of the scheme, the problem of nonlinear heat conduction is considered. In this context the main emphasis is given to successive substitution-type schemes. To verify the improved numerical characteristics associated with partitioned multiply scaled solvers, results are presented for several benchmark examples.
Design Considerations for Heavily-Doped Cryogenic Schottky Diode Varactor Multipliers
NASA Technical Reports Server (NTRS)
Schlecht, E.; Maiwald, F.; Chattopadhyay, G.; Martin, S.; Mehdi, I.
2001-01-01
Diode modeling for Schottky varactor frequency multipliers above 500 GHz is presented with special emphasis placed on simple models and fitted equations for rapid circuit design. Temperature- and doping-dependent mobility, resistivity, and avalanche current multiplication and breakdown are presented. Next is a discussion of static junction current, including the effects of tunneling as well as thermionic emission. These results have been compared to detailed measurements made down to 80 K on diodes fabricated at JPL, followed by a discussion of the effect on multiplier efficiency. Finally, a simple model of current saturation in the undepleted active layer suitable for inclusion in harmonic balance simulators is derived.
Magnetic mirror trap with electron-cyclotron plasma heating as a source of multiply charged ions
Golovanivskii, K.S.
1986-03-01
This paper presents the physical operating principles of sources of multiply charged ions using electron cyclotron resonance. It is shown that the conditions that must be satisfied for multiple ionization are well matched to the conditions of effective plasma confinement in a magnetic mirror trap when a collision mode of confinement is provided. Plasma stability with hot electrons in the mirror magnetic trap and the mechanisms of plasma heating by highfrequency fields are analyzed. Two sources of multiply charged ions with ECR plasma heating are examined. Evaluations of the future of this area are given.
Imaging beyond the ballistic limit in coherence imaging using multiply scattered light.
Giacomelli, Michael G; Wax, Adam
2011-02-28
We present an imaging system based on low coherence interferometric detection of multiply scattered light for extended depth imaging into highly scattering media. By incorporating angle-resolved detection, coherence imaging with multiply scattered photons is shown to be both feasible and potentially superior to existing techniques for performing time-resolved measurements of scattered light. Imaging is demonstrated through nearly 100 mean free paths of scattering phantom in a single-ended geometry. The resolution and imaging contrast are compared to those obtained with conventional OCT systems which chiefly detect singly scattered light. PMID:21369257
A Schottky/2-DEG varactor diode for millimeter and submillimeter wave multiplier applications
NASA Technical Reports Server (NTRS)
Peatman, W. C. B.; Crowe, Thomas W.; Shur, M.; Gelmont, B.
1992-01-01
A new Schottky diode is investigated for use as a multiplier element in the millimeter and submillimeter wavelength regions. The new diode is based on the Schottky contact at the edge of a 2-dimensional electron gas (2-DEG). As a negative voltage is applied to the Schottky contact, the depletion layer between the Schottky contact and the 2-DEG expands and the junction capacitance decreases, resulting in a nonlinear capacitance-voltage characteristic. In this paper, we outline the theory, design, fabrication, and evaluation of the new device. Recent results include devices having cutoff frequencies of 1 THz and above. Preliminary multiplier results are also presented.
Nonlinear realization of local symmetries of AdS space
Clark, T.E.; Love, S.T.; Nitta, Muneto; Veldhuis, T. ter
2005-10-15
Coset methods are used to construct the action describing the dynamics associated with the spontaneous breaking of the local symmetries of AdS{sub d+1} space due to the embedding of an AdS{sub d} brane. The resulting action is an SO(2,d) invariant AdS form of the Einstein-Hilbert action, which in addition to the AdS{sub d} gravitational vielbein, also includes a massive vector field localized on the brane. Its long wavelength dynamics is the same as a massive Abelian vector field coupled to gravity in AdS{sub d} space.
NASA Technical Reports Server (NTRS)
Freedman, Ellis; Ryan, Robert; Pagnutti, Mary; Holekamp, Kara; Gasser, Gerald; Carver, David; Greer, Randy
2007-01-01
Spectral Dark Subtraction (SDS) provides good ground reflectance estimates across a variety of atmospheric conditions with no knowledge of those conditions. The algorithm may be sensitive to errors from stray light, calibration, and excessive haze/water vapor. SDS seems to provide better estimates than traditional algorithms using on-site atmospheric measurements much of the time.
[Development of a digital chest phantom for studies on energy subtraction techniques].
Hayashi, Norio; Taniguchi, Anna; Noto, Kimiya; Shimosegawa, Masayuki; Ogura, Toshihiro; Doi, Kunio
2014-03-01
Digital chest phantoms continue to play a significant role in optimizing imaging parameters for chest X-ray examinations. The purpose of this study was to develop a digital chest phantom for studies on energy subtraction techniques under ideal conditions without image noise. Computed tomography (CT) images from the LIDC (Lung Image Database Consortium) were employed to develop a digital chest phantom. The method consisted of the following four steps: 1) segmentation of the lung and bone regions on CT images; 2) creation of simulated nodules; 3) transformation to attenuation coefficient maps from the segmented images; and 4) projection from attenuation coefficient maps. To evaluate the usefulness of digital chest phantoms, we determined the contrast of the simulated nodules in projection images of the digital chest phantom using high and low X-ray energies, soft tissue images obtained by energy subtraction, and "gold standard" images of the soft tissues. Using our method, the lung and bone regions were segmented on the original CT images. The contrast of simulated nodules in soft tissue images obtained by energy subtraction closely matched that obtained using the gold standard images. We thus conclude that it is possible to carry out simulation studies based on energy subtraction techniques using the created digital chest phantoms. Our method is potentially useful for performing simulation studies for optimizing the imaging parameters in chest X-ray examinations.
An Analysis of Word Problems in School Mathematics Texts: Operation of Addition and Subtraction
ERIC Educational Resources Information Center
Singh, Parmjit
2006-01-01
This paper discusses the types of word problems represented in Malaysia's primary one, primary two and primary three mathematics texts based on Van De Walle's model (1998) in the operations of addition and subtraction. A test was constructed to measure students' success based on this model. The data from this study indicates that the Malaysian…
Correlated noise in networks of gravitational-wave detectors: Subtraction and mitigation
NASA Astrophysics Data System (ADS)
Thrane, E.; Christensen, N.; Schofield, R. M. S.; Effler, A.
2014-07-01
One of the key science goals of advanced gravitational-wave detectors is to observe a stochastic gravitational-wave background. However, recent work demonstrates that correlated magnetic fields from Schumann resonances can produce correlated strain noise over global distances, potentially limiting the sensitivity of stochastic background searches with advanced detectors. In this paper, we estimate the correlated noise budget for the worldwide advanced detector network and conclude that correlated noise may affect upcoming measurements. We investigate the possibility of a Wiener filtering scheme to subtract correlated noise from Advanced LIGO searches, and estimate the required specifications. We also consider the possibility that residual correlated noise remains following subtraction, and we devise an optimal strategy for measuring astronomical parameters in the presence of correlated noise. Using this new formalism, we estimate the loss of sensitivity for a broadband, isotropic stochastic background search using 1 yr of LIGO data at design sensitivity. Given our current noise budget, the uncertainty with which LIGO can estimate energy density will likely increase by a factor of ≈12—if it is impossible to achieve significant subtraction. Additionally, narrow band cross-correlation searches may be severely affected at low frequencies f ≲70 Hz without effective subtraction.
Detecting small anatomical change with 3D serial MR subtraction images
NASA Astrophysics Data System (ADS)
Holden, Mark; Denton, Erica R. E.; Jarosz, J. M.; Cox, T. C.; Studholme, Colin; Hawkes, David J.; Hill, Derek L.
1999-05-01
Spoiled gradient echo volume MR scans were obtained from 5 growth hormone (GH) patients and 6 normal controls. The patients were scanned before treatment and after 3 and 6 months of GH therapy. The controls were scanned at similar intervals. A calibration phantom was scanned on the same day as each subject. The phantom images were registered with a 9 degree of freedom algorithm to measure scaling errors due to changes in scanner calibration. The second and third images were each registered with a 6 degree of freedom algorithm to the first (baseline) image by maximizing normalized mutual information, and transformed, with and without scaling error correction, using sinc interpolation. Each registered and transformed image had the baseline image subtracted to generate a difference image. Two neuro-radiologists were trained to detect structural change with difference images containing synthetic misregistration and scale changes. They carried out a blinded assessment of anatomical change for the unregistered; aligned and subtracted; and scale corrected, aligned and subtracted images. The results show a significant improvement in the detection of structural change and inter-observer agreement when aligned and subtracted images were used instead of unregistered ones. The structural change corresponded to an increase in brain: CSF ratio.
Technology Transfer Automated Retrieval System (TEKTRAN)
Subtractive suppressive hybridization (SSH) was used to characterize the diapause transcriptome of the flesh fly Sarcophaga crassipalpis. Through these efforts, we isolated 97 unique clones which were used as probes in northern hybridization to assess their expression during diapause. Of these, 17...
ERIC Educational Resources Information Center
Bryant, Peter; Rendu, Alison; Christie, Clare
1999-01-01
Examined whether 5- and 6-year-olds understand that addition and subtraction cancel each other and whether this understanding is based on identity or quantity of addend and subtrahend. Found that children used inversion principle. Six- to eight-year-olds also used inversion and decomposition to solve a + b - (B+1) problems. Concluded that…
Strategies for Solving Simple Subtractions as Reflected by Children's Verbal Reports.
ERIC Educational Resources Information Center
Svenson, Ola; Hedenborg, Maj-Lene
1980-01-01
Children, 9-11 years old, solved subtraction problems in the form of M-N=..., then gave a verbal report on the thought processes used, analysis of which utilized a model based on analyses of reaction times, and resulted in a more detailed process model. (AN)
Prado, Jérôme; Mutreja, Rachna; Booth, James R
2014-07-01
Mastering single-digit arithmetic during school years is commonly thought to depend upon an increasing reliance on verbally memorized facts. An alternative model, however, posits that fluency in single-digit arithmetic might also be achieved via the increasing use of efficient calculation procedures. To test between these hypotheses, we used a cross-sectional design to measure the neural activity associated with single-digit subtraction and multiplication in 34 children from 2nd to 7th grade. The neural correlates of language and numerical processing were also identified in each child via localizer scans. Although multiplication and subtraction were undistinguishable in terms of behavior, we found a striking developmental dissociation in their neural correlates. First, we observed grade-related increases of activity for multiplication, but not for subtraction, in a language-related region of the left temporal cortex. Second, we found grade-related increases of activity for subtraction, but not for multiplication, in a region of the right parietal cortex involved in the procedural manipulation of numerical quantities. The present results suggest that fluency in simple arithmetic in children may be achieved by both increasing reliance on verbal retrieval and by greater use of efficient quantity-based procedures, depending on the operation. PMID:25089323
ERIC Educational Resources Information Center
Begeer, Sander; Terwogt, Mark Meerum; Lunenburg, Patty; Stegge, Hedy
2009-01-01
The development of additive ("If only I had done...") and subtractive ("If only I had not done....") counterfactual reasoning was examined in children with High Functioning Autism Spectrum Disorders (HFASD) (n = 72) and typically developing controls (n = 71), aged 6-12 years. Children were presented four stories where they could generate…
Developmental dissociation in the neural responses to simple multiplication and subtraction problems
Prado, Jérôme; Mutreja, Rachna; Booth, James R.
2014-01-01
Mastering single-digit arithmetic during school years is commonly thought to depend upon an increasing reliance on verbally memorized facts. An alternative model, however, posits that fluency in single-digit arithmetic might also be achieved via the increasing use of efficient calculation procedures. To test between these hypotheses, we used a cross-sectional design to measure the neural activity associated with single-digit subtraction and multiplication in 34 children from 2nd to 7th grade. The neural correlates of language and numerical processing were also identified in each child via localizer scans. Although multiplication and subtraction were undistinguishable in terms of behavior, we found a striking developmental dissociation in their neural correlates. First, we observed grade-related increases of activity for multiplication, but not for subtraction, in a language-related region of the left temporal cortex. Second, we found grade-related increases of activity for subtraction, but not for multiplication, in a region of the right parietal cortex involved in the procedural manipulation of numerical quantities. The present results suggest that fluency in simple arithmetic in children may be achieved by both increasing reliance on verbal retrieval and by greater use of efficient quantity-based procedures, depending on the operation. PMID:25089323
Fostering Taiwanese Preschoolers' Understanding of the Addition-Subtraction Inverse Principle
ERIC Educational Resources Information Center
Lai, Meng-Lung; Baroody, Arthur J.; Johnson, Amanda R.
2008-01-01
The present research involved gauging preschoolers' learning potential for a key arithmetic concept, the addition-subtraction inverse principle (e.g., 2+1-1=2). Sixty 4- and 5-year-old Taiwanese children from two public preschools serving low- and middle-income families participated in the training experiment. Half were randomly assigned to an…
Preschoolers' Nonsymbolic Arithmetic with Large Sets: Is Addition More Accurate than Subtraction?
ERIC Educational Resources Information Center
Shinskey, Jeanne L.; Chan, Cindy Ho-man; Coleman, Rhea; Moxom, Lauren; Yamamoto, Eri
2009-01-01
Adult and developing humans share with other animals analog magnitude representations of number that support nonsymbolic arithmetic with large sets. This experiment tested the hypothesis that such representations may be more accurate for addition than for subtraction in children as young as 3 1/2 years of age. In these tasks, the experimenter hid…
ERIC Educational Resources Information Center
Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin
2011-01-01
Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…
ERIC Educational Resources Information Center
Sci, Eve
2011-01-01
After administering an end of unit assessment written by the school's math program, teachers of three second grade classes in a New York City school noticed a majority of the students had not demonstrated mastery of subtracting two, two-digit numbers. The teachers worked with the school's math coach to implement an instructional unit that required…
Operational Momentum in Large-Number Addition and Subtraction by 9-Month-Olds
ERIC Educational Resources Information Center
McCrink, Koleen; Wynn, Karen
2009-01-01
Recent studies on nonsymbolic arithmetic have illustrated that under conditions that prevent exact calculation, adults display a systematic tendency to overestimate the answers to addition problems and underestimate the answers to subtraction problems. It has been suggested that this "operational momentum" results from exposure to a…
Running of the contact interactions in chiral N3LO potentials from subtractive renormalization
NASA Astrophysics Data System (ADS)
Batista, E. F.; Szpigel, S.; Timóteo, V. S.
2015-07-01
In this work a subtracted kernel renormalization procedure (SKM) is applied to the chiral NN potential up to next-to-next-to-next-to-leading-order (N3 LO) to obtain the running of the renormalized contact strengths with the subtraction scale μ and the phase shifts for all uncoupled waves with contact interaction (S,P,D). We use two potentials constructed within the framework of Weinberg's approach to ChEFT, which provide a very accurate description of NN scattering data below laboratory energies E ∼ 350 MeV, namely Epelbaum, Glöckle and Meissner (N3LO-EGM) and Entem and Machleidt (N3LO-EM). For both potentials, we consider a large cutoff (30 fm-1) and analyze the phases and the running of the contact strengths with the subtraction point μ by making a fit of the K-matrix with five subtractions to the K-matrix from the Nijmegen II potential at low energies (E ≤ 20 MeV).
ERIC Educational Resources Information Center
Rao, Shaila; Kane, Martha T.
2009-01-01
This study assessed effectiveness of simultaneous prompting procedure in teaching two middle school students with cognitive impairment decimal subtraction using regrouping. A multiple baseline, multiple probe design replicated across subjects successfully taught two students with cognitive impairment at middle school level decimal subtraction…
Dipole splitting algorithm: A practical algorithm to use the dipole subtraction procedure
NASA Astrophysics Data System (ADS)
Hasegawa, K.
2015-11-01
The Catani-Seymour dipole subtraction is a general and powerful procedure to calculate the QCD next-to-leading order corrections for collider observables. We clearly define a practical algorithm to use the dipole subtraction. The algorithm is called the dipole splitting algorithm (DSA). The DSA is applied to an arbitrary process by following well defined steps. The subtraction terms created by the DSA can be summarized in a compact form by tables. We present a template for the summary tables. One advantage of the DSA is to allow a straightforward algorithm to prove the consistency relation of all the subtraction terms. The proof algorithm is presented in the following paper [K. Hasegawa, arXiv:1409.4174]. We demonstrate the DSA in two collider processes, pp to μ -μ + and 2 jets. Further, as a confirmation of the DSA, it is shown that the analytical results obtained by the DSA in the Drell-Yan process exactly agree with the well known results obtained by the traditional method.
Assessment of Subtraction Scene Understanding Using a Story-Generation Task
ERIC Educational Resources Information Center
Kinda, Shigehiro
2010-01-01
The present study used a new assessment technique, the story-generation task, to examine students' understanding of subtraction scenes. The students from four grade levels (110 first-, 107 third-, 110 fourth- and 119 sixth-graders) generated stories under the constraints provided by a picture (representing Change, Combine or Compare scene) and a…
Generating Scenarios of Addition and Subtraction: A Study of Japanese University Students
ERIC Educational Resources Information Center
Kinda, Shigehiro
2013-01-01
Students are presented with problems involving three scenario types of addition and subtraction in elementary mathematics: one dynamic ("Change") and two static ("Combine, Compare"). Previous studies have indicated that the dynamic type is easier for school children, whereas the static types are more difficult and comprehended only gradually…
Developing Prospective Teachers' Understanding of Addition and Subtraction with Whole Numbers
ERIC Educational Resources Information Center
Roy, George J.
2014-01-01
This study was situated in a semester-long classroom teaching experiment examining prospective teachers' understanding of number concepts and operations. The purpose of this paper is to describe the learning goals, tasks, and tools used to cultivate prospective teachers' understanding of addition and subtraction with whole numbers.…
ERIC Educational Resources Information Center
Mota, A. R.; Lopes dos Santos, J. M. B.
2014-01-01
Students' misconceptions concerning colour phenomena and the apparent complexity of the underlying concepts--due to the different domains of knowledge involved--make its teaching very difficult. We have developed and tested a teaching device, the addition table of colours (ATC), that encompasses additive and subtractive mixtures in a single…
[Development of a digital chest phantom for studies on energy subtraction techniques].
Hayashi, Norio; Taniguchi, Anna; Noto, Kimiya; Shimosegawa, Masayuki; Ogura, Toshihiro; Doi, Kunio
2014-03-01
Digital chest phantoms continue to play a significant role in optimizing imaging parameters for chest X-ray examinations. The purpose of this study was to develop a digital chest phantom for studies on energy subtraction techniques under ideal conditions without image noise. Computed tomography (CT) images from the LIDC (Lung Image Database Consortium) were employed to develop a digital chest phantom. The method consisted of the following four steps: 1) segmentation of the lung and bone regions on CT images; 2) creation of simulated nodules; 3) transformation to attenuation coefficient maps from the segmented images; and 4) projection from attenuation coefficient maps. To evaluate the usefulness of digital chest phantoms, we determined the contrast of the simulated nodules in projection images of the digital chest phantom using high and low X-ray energies, soft tissue images obtained by energy subtraction, and "gold standard" images of the soft tissues. Using our method, the lung and bone regions were segmented on the original CT images. The contrast of simulated nodules in soft tissue images obtained by energy subtraction closely matched that obtained using the gold standard images. We thus conclude that it is possible to carry out simulation studies based on energy subtraction techniques using the created digital chest phantoms. Our method is potentially useful for performing simulation studies for optimizing the imaging parameters in chest X-ray examinations. PMID:24647055
Standardization and adult norms for the sequential subtracting tasks of serial 3's and 7's.
Bristow, Thomas; Jih, Chwan-Shyang; Slabich, Artrina; Gunn, Jamie
2016-01-01
The Serial 3's and 7's subtraction tasks are traditionally used in mental status examinations. The usefulness of these tasks is based upon the assumption that they measure attention and mental concentration. However, there is no uniform method of administration, and there are no recognized norms for these subtraction tasks, which has led some in the field of psychiatry and neuropsychology to conclude that the tests are not useful. The purpose of this research had three goals: (a) to create a standardization of the administration, (b) to provide a structured and consistent framework for the data evaluation, and (c) to create adult norms as a frame of reference for interpretation. The study investigated normal control subjects (N = 204) and specific variables of interest included both efficiency and accuracy of performance. The results demonstrated that when used conjointly, Serial 3's and Serial 7's are an efficient and accurate measure of sequential subtracting, but even more importantly, the study revealed the hierarchical increase in cognitive demand when the performances between 3's and 7's were compared. With standardization and norms, serial subtraction becomes a more effective screening technique within the context of a mental status examination. Similarly, the conjoint administration of these tasks yields synergistic data that can be useful in determining deficits in the cognitive domains of attention and working memory. PMID:27218700
ERIC Educational Resources Information Center
Chen, Yen-Hua; Looi, Chee-Kit; Lin, Chiu-Pin; Shao, Yin-Juan; Chan, Tak-Wai
2012-01-01
While addition and subtraction is a key mathematical skill for young children, a typical activity for them in classrooms involves doing repetitive arithmetic calculation exercises. In this study, we explore a collaborative way for students to learn these skills in a technology-enabled way with wireless computers. Two classes, comprising a total of…
[X-ray semiotics of sialolithiasis in functional digital subtraction sialography].
Iudin, L A; Kondrashin, S A; Afanas'ev, V V; Shchipskiĭ, A V
1995-01-01
Twenty-seven patients with sialolithiasis were examined using functional subtraction sialography developed by the authors. Differential diagnostic signs characterizing the degree of involvement of the salivary gland were defined. High efficacy of the method helps correctly plan the treatment strategy.
Perdiguero, Pedro; Collada, Carmen; Barbero, María Del Carmen; García Casado, Gloria; Cervera, María Teresa; Soto, Alvaro
2012-01-01
Climate change is a major challenge particularly for forest tree species, which will have to face the severe alterations of environmental conditions with their current genetic pool. Thus, an understanding of their adaptive responses is of the utmost interest. In this work we have selected Pinus pinaster as a model species. This pine is one of the most important conifers (for which molecular tools and knowledge are far more scarce than for angiosperms) in the Mediterranean Basin, which is characterised in all foreseen scenarios as one of the regions most drastically affected by climate change, mainly because of increasing temperature and, particularly, by increasing drought. We have induced a controlled, increasing water stress by adding PEG to a hydroponic culture. We have generated a subtractive library, with the aim of identifying the genes induced by this stress and have searched for the most reliable expressional candidate genes, based on their overexpression during water stress, as revealed by microarray analysis and confirmed by RT-PCR. We have selected a set of 67 candidate genes belonging to different functional groups that will be useful molecular tools for further studies on drought stress responses, adaptation, and population genomics in conifers, as well as in breeding programs.
ERIC Educational Resources Information Center
Edwards-Omolewa, Nicola D.
2011-01-01
Gender differences in the strategies elementary school children use to solve multidigit addition and subtraction story problems that require regrouping are investigated in two studies. Study 1 replicates the Fennema and colleagues (1998) study by reexamining previously published data on 72 children's addition and subtraction solution strategies.…
NASA Astrophysics Data System (ADS)
Borsato, Riccardo; Ohlsson Sax, Olof; Sfondrini, Alessandro; Stefański, Bogdan, Jr.; Torrielli, Alessandro
2013-09-01
We determine the all-loop dressing phases of the AdS3/CFT2 integrable system related to type IIB string theory on AdS3×S3×T4 by solving the recently found crossing relations and studying their singularity structure. The two resulting phases present a novel structure with respect to the ones appearing in AdS5/CFT4 and AdS4/CFT3. In the strongly coupled regime, their leading order reduces to the universal Arutyunov-Frolov-Staudacher phase as expected. We also compute their subleading order and compare it with recent one-loop perturbative results and comment on their weak-coupling expansion.
Bubbling geometries for AdS2× S2
NASA Astrophysics Data System (ADS)
Lunin, Oleg
2015-10-01
We construct BPS geometries describing normalizable excitations of AdS2×S2. All regular horizon-free solutions are parameterized by two harmonic functions in R 3 with sources along closed curves. This local structure is reminiscent of the "bubbling solutions" for the other AdS p ×S q cases, however, due to peculiar asymptotic properties of AdS2, one copy of R 3 does not cover the entire space, and we discuss the procedure for analytic continuation, which leads to a nontrivial topological structure of the new geometries. We also study supersymmetric brane probes on the new geometries, which represent the AdS2×S2 counterparts of the giant gravitons.
Boughezal, R.; Gehrmann-De Ridder, A.; Ritzmann, M.
2011-02-01
The antenna subtraction formalism allows to calculate QCD corrections to jet observables. Within this formalism, the subtraction terms are constructed using antenna functions describing all unresolved radiation between a pair of hard radiator partons. In this paper, we focus on the subtraction terms for double real radiation contributions to jet observables in hadron-hadron collisions evaluated at NNLO. An essential ingredient to these subtraction terms are the four-parton antenna functions with both radiators in the initial state. We outline the construction of the double real subtraction terms, classify all relevant antenna functions and describe their integration over the relevant antenna phase space. For the initial-initial antenna functions with two quark flavours, we derive the phase space master integrals and obtain the integrated antennae.
Fei, Shao-Ming; Gao, Xiu-Hong; Wang, Xiao-Hong; Wang, Zhi-Xi; Wu, Ke
2003-08-01
The separability and entanglement of quantum mixed states in C{sup 2}(multiply-in-circle sign)C{sup 3}(multiply-in-circle sign)C{sup N} composite quantum systems are investigated. It is shown that all quantum states {rho} with positive partial transposes and rank r({rho}){<=}N are separable.
[Value-Added--Adding Economic Value in the Food Industry].
ERIC Educational Resources Information Center
Welch, Mary A., Ed.
1989-01-01
This booklet focuses on the economic concept of "value added" to goods and services. A student activity worksheet illustrates how the steps involved in processing food are examples of the concept of value added. The booklet further links food processing to the idea of value added to the Gross National Product (GNP). Discussion questions, a student…
Effective CPD on a Large Scale: Examining the Development of Multipliers
ERIC Educational Resources Information Center
Roesken-Winter, Bettina; Schüler, Sven; Stahnke, Rebekka; Blömeke, Sigrid
2015-01-01
Much research has been conducted on exploring teacher learning and constituting Continuous Professional Development (CPD) designs for teachers. Yet, little is known about appropriate design principles of CPD for teacher trainers/multipliers who in turn are supposed to provide CPD for teachers. The German Center for Mathematics Teacher Education…
A new bit-serial systolic multiplier over GF(2/sup m/)
Zhou, B.B.
1988-06-01
A new bit-serial systolic array is developed to compute multiplications over GF(2/sup m/). In contrast to another systolic multiplier, this new systolic algorithm allows the input elements to enter a linear systolic array in the same order and the system only requires one control signal.
ERIC Educational Resources Information Center
Chou, Chih-Ping; Bentler, P. M.
1990-01-01
The empirical performance under null/alternative hypotheses of the likelihood ratio difference test (LRDT); Lagrange Multiplier test (evaluating the impact of model modification with a specific model); and Wald test (using a general model) were compared. The new tests for covariance structure analysis performed as well as did the LRDT. (RLC)
Minocycline sensitivity related to the phage type of multiply resistant staphylococci.
Rich, G; Davidson, J
1975-06-01
Clinical isolated of multiply antibiotic-resistant strains of Staphlococcus aureus were divided into three groups by phage typing. The most prevalent type, which is usually cloxacillin resistant, was found to be moderately sensitive to minocycline. Unfortunately the degree of sensitivity is not sufficient to warrant the use of the antibiotic in severe staphlococcal infection.
A Manual for Assessment and Training of Severely Multiply Handicapped Deaf-Blind Students.
ERIC Educational Resources Information Center
Burton, Rosemarie A.; And Others
Intended for teacher use, the manual provides for the assessment and training of severely multiply handicapped deaf-blind students with sections on self help, motor development, and sensory stimulation training. Included for each skill are an individual rating scale for periodic assessments, a task analysis, and an actual teaching procedure. Found…
ERIC Educational Resources Information Center
Carner, Lauren A.; Levy, Linda
An analysis of the regulatory activity of eight neurologically impaired/multiply handicapped children and eight normally learning children in two age groups (means 3 years 8 months and 5 years 9 months) was made. The children attempted to resolve conflicts that arose while balancing two wooden blocks, identical in appearance, except that one…
A Classical Conditioning Procedure for the Hearing Assessment of Multiply Handicapped Persons.
ERIC Educational Resources Information Center
Lancioni, Giulio E.; And Others
1989-01-01
Hearing assessments of multiply handicapped children/adolescents were conducted using classical conditioning (with an air puff as unconditioned stimulus) and operant conditioning (with a modified visual reinforcement audiometry procedure or edible reinforcement). Findings indicate that classical conditioning was successful with 21 of the 23…
ERIC Educational Resources Information Center
Gates, Carmella Ficociello
1985-01-01
A survey of visually impaired children (from birth to age 12) in the Rocky Mountain/Great Plains region indicated that the majority were multiply handicapped, and that within this group, the greatest number were in the mild to moderate range. Data are presented on age ranges, current service delivery options, vocational and alternative-living…
An Exploration of Social Media Use among Multiply Minoritized LGBTQ Youth
ERIC Educational Resources Information Center
Lucero, Alfie Leanna
2013-01-01
This study responds to a need for research in a fast-growing and significant area of study, that of exploring, understanding, and documenting the numerous ways that multiply marginalized LGBTQ youth between the ages of 14 and 17 use social media. The primary research question examined whether social media provide safe spaces for multiply…
Regulation of a lightweight high efficiency capacitator diode voltage multiplier dc-dc converter
NASA Technical Reports Server (NTRS)
Harrigill, W. T., Jr.; Myers, I. T.
1976-01-01
A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.
Regulation of a lightweight high efficiency capacitor diode voltage multiplier dc-dc converter
NASA Technical Reports Server (NTRS)
Harrigill, W. T., Jr.; Myers, I. T.
1976-01-01
A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.
Water Misting: Treating Self-Injurious Behavior in a Multiply Handicapped, Visually Impaired Child.
ERIC Educational Resources Information Center
Fehr, A.; Beckwith, B. E.
1989-01-01
A water mist was employed as a punisher to reduce head hitting in a 10-year-old multiply handicapped, visually impaired child. Results indicated that water mist alone was effective in reducing the frequency of head hits during meals, but other situations required the addition of primary reinforcers, stimulus control, or both. (Author/JDD)
Highly enriched multiply-labeled stable isotopic compounds as atmospheric tracers
Goldblatt, M.; McInteer, B.B.
1974-01-29
Compounds multiply-labeled with stable isotopes and highly enriched in these isotopes are readily capable of detection in tracer experiments involving high dilutions. Thus, for example, /sup 13/C/sup 18/O/sub 2/ provides a useful tracer for following atmospheric pol lution produced as a result of fossil fuel burning. (Official Gazette)
ERIC Educational Resources Information Center
Smith, Donna K., Ed.
The curriculum guide for early childhood education of the multiply handicapped covers motor, academic, and perceptual skills. Operational definitions and developmental characteristics of the mentally retarded introduce the guide. Considered are the role of the teacher and teacher's aide, the classroom facilities, and scheduling. A chapter on…
ERIC Educational Resources Information Center
Sandler, Allen G.; McLain, Susan C.
1987-01-01
Investigation of the reinforcing properties of vestibular stimulation with five multiply disabled severely retarded young children indicated that vestibular stimulation (10 seconds of swinging) was reinforcing to all subjects and was preferred (over food, praise, visual, and auditory stimulation) by four of the five children. (Author/DB)
ERIC Educational Resources Information Center
Schloss, Patrick J.
1984-01-01
The article provides guidelines for developing curriculum objectives for multiply involved hearing-impaired students. Emphasis is placed on procedures for establishing instructional priorities, assessing the learner against these priorities, selecting and using prosthetics to overcome learning and behavioral deficits, providing educational…
Low-voltage harmonic multiplying gyrotron traveling-wave amplifier in G band
Yeh, Y. S.; Guo, Y. W.; Kao, B. H.; Chen, C. H.; Wang, Z. W.; Hung, C. L.; Chang, T. H.
2015-12-15
Harmonic multiplying operation in a gyrotron traveling-wave amplifier (gyro-TWA) permits for magnetic field reduction and frequency multiplication. Lowering a beam voltage is an important step toward miniaturization of a harmonic multiplying gyro-TWA. However, the additional degree of freedom that is provided by the multitude cyclotron harmonics in a low-voltage harmonic multiplying gyro-TWA still easily generates various competing modes. An improved mode-selective circuit, using circular waveguides with various radii, can provide the rejection points within the frequency range to suppress competing modes. Simulated results reveal that the mode-selective circuit can provide an attenuation of more than 14 dB to suppress the competing modes. Furthermore, the performance of the gyro-TWA is analyzed for studying the sensitivity of the saturated output power and full width at half maximum bandwidth of the gyro-TWA to the beam voltage and the magnetic field. A stable low-voltage harmonic multiplying gyro-TWA with the mode-selective circuit is predicted to yield a peak output power of 24 kW at 200.4 GHz, corresponding to a saturated gain of 56 dB at an interaction efficiency of 20%. The full width at half maximum bandwidth is 3.0 GHz.
A novel four-quadrant analog multiplier using SOI four-gate transitors (G4-FETs)
NASA Technical Reports Server (NTRS)
Akarvardar, K.; Chen, S.; Blalock, B. J.; Cristoloveanu, S.; Gentil, P.; Mojarradi, M.
2005-01-01
A novel analog muliplier using SOI four-gate transistors (G4-FETs) is presented. Thanks to the multiple inputs of the G4-FET that may be biased independently, the number of transistors in the proposed circuit is dramatically reduced, compared to conventional single-gate MOSFET based multipliers.
ERIC Educational Resources Information Center
Neidert, Pamela L.; Iwata, Brian A.; Dozier, Claudia L.
2005-01-01
We describe the assessment and treatment of 2 children with autism spectrum disorder whose problem behaviors (self-injury, aggression, and disruption) were multiply controlled. Results of functional analyses indicated that the children's problem behaviors were maintained by both positive reinforcement (attention) and negative reinforcement (escape…
Production of multiply charge-state ions in a multicusp ion source
Williams, M.D.; deVries, G.J.; Gough, R.A.; Leung, K.N.; Monroy, M.
1996-03-01
High charge state ion beams are commonly used in atomic and nuclear physics experiments. Multiply charged ions are normally produced in an ECR or in an EBIS. Multicusp generators can confine primary electrons very efficiently. Therefore, the electrical and gas efficiencies of these devices are high. Since the magnetic cusp fields are localized near the chamber wall, large volumes of uniform and high density plasmas can be obtained at low pressure, conditions favorable for the formation of multiply charged state ions. Attempts have been made at LBNL to generate multiply charged ion beams by employing a 25-cm diam by 25-cm long multicusp source. Experimental results demonstrated that charge states as high as 7+ can be obtained with argon or xenon plasmas. Multiply charged metallic ions such as tungsten and titanium have also been successfully formed in the multicusp source by evaporation and sputtering processes. In order to extend the charge state to higher values, a novel technique of injecting high energy electrons into the source plasma is proposed. If this is successful, the multicusp source will become very useful for radioactive beam accelerators, ion implantation, and nuclear physics applications. {copyright} {ital 1996 American Institute of Physics.}
Micro Application for the Multiply Handicapped in a Public School Setting.
ERIC Educational Resources Information Center
Ollie, Phyllis A.; Ryder, Ramela
The paper discusses ways in which the Apple II plus and Apple IIe computers can be adapted to become highly effective tools in the education of the physically/multiply handicapped student. The role of word processing programs as communication aids, alternative input and output devices, and innovative software programs is examined. Among the…
ERIC Educational Resources Information Center
Thomas, M. Angele, Ed.
Presented are 12 author contributed chapters which developed out of an invisible college of leaders concerned with providing services to the severely, profoundly, and multiply handicapped. Stressed throughout the book are such needs as the need to listen to parents, the need for new training programs for teachers of the severely handicapped, the…
MCMC2 (version 1.1.1): A Monte Carlo code for multiply charged clusters
NASA Astrophysics Data System (ADS)
Bonhommeau, David A.
2015-11-01
This new version of the MCMC2 program for modeling the thermodynamic and structural properties of multiply-charged clusters fixes some minor bugs present in earlier versions. A figure representing the required RAM per replica as a function of the cluster size (N ≤ 20000) is also provided as benchmark.
NASA Astrophysics Data System (ADS)
Brugière, Timothée; Mayer, Fréderic; Fereyre, Pierre; Guérin, Cyrille; Dominjon, Agnés; Barbier, Rémi
2015-07-01
Scientific low light imaging devices benefit today from designs for pushing the mean noise to the single electron level. When readout noise reduction reaches its limit, signal-to-noise ratio improvement can be driven by an electron multiplication process, driven by impact ionization, before adding the readout noises. This concept already implemented in CCD structures using extra-pixel shift registers can today be integrated inside each pixel in CMOS technology. The EBCMOS group at IPNL is in charge of the characterization of new prototypes developed by E2V using this concept: the electron multiplying CMOS (EMCMOS). The CMOS technology enables electron multiplication inside the photodiode itself, and thus, an overlap of the charge integration and multiplication. A new modeling has been developed to describe the output signal mean and variance after the impact ionization process in such a case. In this paper the feasibility of impact ionization process inside a 8 μm-pitch pixel is demonstrated. The new modeling is also validated by data and a value of 0.32% is obtained for the impact ionization parameter α with an electric field intensity of 24 V / μm.
Elaboration and research of planetary precessional multiplier type K-H-V
NASA Astrophysics Data System (ADS)
Bostan, I.; Dulgheru, V.; Ciobanu, R.
2016-08-01
The multiplier is an indispensable part of the micro hydropower plant and high power wind turbine. It helps to increase rotor low speeds limited by the water flow small velocity and by the relative big placement diameter of the blades that participate in the energy conversion. For example, the microhydrostation rotor's speed is (2 - 3) min'1 for water flow velocity V= (1...1,6) m/s and for blade placement diameter D = 4 m. Diversity of requirements forwarded by the beneficiaries of mechanical transmissions consists, in particular, in increasing reliability, efficiency and lifting capacity, and in reducing the mass and dimensions. It becomes more and more difficult to satisfy the mentioned demands by partial updating of traditional transmissions. The target problem can be solved with special effects by developing new types of multipliers based on precessional planetary transmissions with multiple gear, that were developed by the authors. Absolute multiplicity of precessional gear (up to 100% pairs of teeth simultaneously involved in gearing, compared to 5%-7% - in classical gearings) provides increased lifting capacity and small mass and dimensions. To mention that until now precessional planetary transmissions have been researched and applied mainly in reducers. Therefore it was necessary to carry out theoretical research to determine the geometrical parameters of the precessional gear that operates in multiplier mode. Also, it was necessary to develop new conceptual diagrams of precessional transmissions that function under multiplier regime. The majority of precessional planetary transmissions diagrams developed previously operate efficiently in reducer's regime. Depending on the structural diagram, precessional transmissions fall into two main types - K-H-V and 2K-H, from which a wide range of constructive solutions with wide kinematical and functional options that operate in multiplier regime.
Action growth for AdS black holes
NASA Astrophysics Data System (ADS)
Cai, Rong-Gen; Ruan, Shan-Ming; Wang, Shao-Jiang; Yang, Run-Qiu; Peng, Rong-Hui
2016-09-01
Recently a Complexity-Action (CA) duality conjecture has been proposed, which relates the quantum complexity of a holographic boundary state to the action of a Wheeler-DeWitt (WDW) patch in the anti-de Sitter (AdS) bulk. In this paper we further investigate the duality conjecture for stationary AdS black holes and derive some exact results for the growth rate of action within the Wheeler-DeWitt (WDW) patch at late time approximation, which is supposed to be dual to the growth rate of quantum complexity of holographic state. Based on the results from the general D-dimensional Reissner-Nordström (RN)-AdS black hole, rotating/charged Bañados-Teitelboim-Zanelli (BTZ) black hole, Kerr-AdS black hole and charged Gauss-Bonnet-AdS black hole, we present a universal formula for the action growth expressed in terms of some thermodynamical quantities associated with the outer and inner horizons of the AdS black holes. And we leave the conjecture unchanged that the stationary AdS black hole in Einstein gravity is the fastest computer in nature.
Superstring theory in AdS(3) and plane waves
NASA Astrophysics Data System (ADS)
Son, John Sang Won
This thesis is devoted to the study of string theory in AdS 3 and its applications to recent developments in string theory. The difficulties associated with formulating a consistent string theory in AdS3 and its underlying SL(2, R) WZW model are explained. We describe how these difficulties can be overcome by assuming that the SL(2, R) WZW model contains spectral flow symmetry. The existence of spectral flow symmetry in the fully quantum treatment is proved by a calculation of the one-loop string partition function. We consider Euclidean AdS 3 with the time direction periodically identified, and compute the torus partition function in this background. The string spectrum can be reproduced by viewing the one-loop calculation as the free energy of a gas of strings, thus providing a rigorous proof of the results based on spectral flow arguments. Next, we turn to spacetimes that are quotients of AdS 3, which include the BTZ black hole and conical spaces. Strings propagating in the conical space are described by taking an orbifold of strings in AdS3. We show that the twisted states of these orbifolds can be obtained by fractional spectral flow. We show that the shift in the ground state energy usually associated with orbifold twists is absent in this case, and offer a unified framework in which to view spectral flow. Lastly, we consider the RNS superstrings in AdS 3 x S3 x M , where M may be K3 or T 4, based on supersymmetric extensions of SL(2, R) and SU(2) WZW models. We construct the physical states and calculate the spectrum. A subsector of this theory describes strings propagating in the six dimensional plane wave obtained by the Penrose limit of AdS3 x S3 x M . We reproduce the plane wave spectrum by taking J and the radius to infinity. We show that the plane wave spectrum actually coincides with the large J spectrum at fixed radius, i.e. in AdS3 x S3. Relation to some recent topics of interest such as the Frolov-Tseytlin string and strings with critical tension
Wu, Meng; Fahrig, Rebecca
2014-11-01
Purpose: The scanning beam digital x-ray system (SBDX) is an inverse geometry fluoroscopic system with high dose efficiency and the ability to perform continuous real-time tomosynthesis in multiple planes. This system could be used for image guidance during lung nodule biopsy. However, the reconstructed images suffer from strong out-of-plane artifact due to the small tomographic angle of the system. Methods: The authors propose an out-of-plane artifact subtraction tomosynthesis (OPAST) algorithm that utilizes a prior CT volume to augment the run-time image processing. A blur-and-add (BAA) analytical model, derived from the project-to-backproject physical model, permits the generation of tomosynthesis images that are a good approximation to the shift-and-add (SAA) reconstructed image. A computationally practical algorithm is proposed to simulate images and out-of-plane artifacts from patient-specific prior CT volumes using the BAA model. A 3D image registration algorithm to align the simulated and reconstructed images is described. The accuracy of the BAA analytical model and the OPAST algorithm was evaluated using three lung cancer patients’ CT data. The OPAST and image registration algorithms were also tested with added nonrigid respiratory motions. Results: Image similarity measurements, including the correlation coefficient, mean squared error, and structural similarity index, indicated that the BAA model is very accurate in simulating the SAA images from the prior CT for the SBDX system. The shift-variant effect of the BAA model can be ignored when the shifts between SBDX images and CT volumes are within ±10 mm in the x and y directions. The nodule visibility and depth resolution are improved by subtracting simulated artifacts from the reconstructions. The image registration and OPAST are robust in the presence of added respiratory motions. The dominant artifacts in the subtraction images are caused by the mismatches between the real object and the prior CT
NASA Astrophysics Data System (ADS)
Gu, Junhua; Xu, Haiguang; Wang, Jingying; An, Tao; Chen, Wen
2013-08-01
We propose a continuous wavelet transform based non-parametric foreground subtraction method for the detection of redshifted 21 cm signal from the epoch of reionization. This method works based on the assumption that the foreground spectra are smooth in frequency domain, while the 21 cm signal spectrum is full of saw-tooth-like structures, thus their characteristic scales are significantly different. We can distinguish them in the wavelet coefficient space easily and perform the foreground subtraction. Compared with the traditional spectral fitting based method, our method is more tolerant to complex foregrounds. Furthermore, we also find that when the instrument has uncorrected response error, our method can also work significantly better than the spectral fitting based method. Our method can obtain similar results with the Wp smoothing method, which is also a non-parametric method, but our method consumes much less computing time.
Addition and subtraction of single phonons in a trapped ion system
NASA Astrophysics Data System (ADS)
Lv, Dingshun; An, Shuoming; Um, Mark; Lu, Yao; Zhang, Jingning; Kim, Kihwan
2014-05-01
We introduce an addition and subtraction of single phonons in a trapped ion system. The creation â† and annihilation â operation have been realized with photons and used for the complete engineering of quantum states of light and the probe of fundamental quantum phenomena. The mathematical description of photon is identical to that of phonon. However, phonon is a particle of quantized matter wave, which should be interpreted differently from photon. We implement the addition and the subtraction of phonon by applying an anti-Jaynes-Cummings type of operation on our trapped ion and performing projective measurements. Our realization can be used for the accurate measurement of position and momentum as well as their relation. This work was supported by the National Basic Research Program of China Grant 2011CBA00300, 2011CBA00301, 2011CBA00302, the National Natural Science Foundation of China Grant 61073174, 61033001, 61061130540.
Mirvish, Ezra D.; Shuda, Masahiro
2016-01-01
Over 20% of human cancers worldwide are associated with infectious agents, including viruses, bacteria, and parasites. Various methods have been used to identify human tumor viruses, including electron microscopic observations of viral particles, immunologic screening, cDNA library screening, nucleic acid hybridization, consensus PCR, viral DNA array chip, and representational difference analysis. With the Human Genome Project, a large amount of genetic information from humans and other organisms has accumulated over the last decade. Utilizing the available genetic databases, Feng et al. (2007) developed digital transcriptome subtraction (DTS), an in silico method to sequentially subtract human sequences from tissue or cellular transcriptome, and discovered Merkel cell polyomavirus (MCV) from Merkel cell carcinoma. Here, we review the background and methods underlying the human tumor virus discoveries and explain how DTS was developed and used for the discovery of MCV. PMID:27242703
van Harskamp, N J; Cipolotti, L
2001-06-01
This study reports for the first time a selective impairment for simple addition in patient FS. Moreover, patient VP presented with a selective impairment for simple multiplication and patient DT with a selective impairment for simple subtraction. These findings are discussed in the context of two of the most influential models for the organisation of arithmetical facts in memory (Dehaene and Cohen, 1995, 1997, and Dagenbach and McCloskey, 1992). Dehaene and Cohen (1995, 1997) have proposed that dissociation between arithmetical facts result from a selective impairment to two different types of processing: rote verbal memory for multiplication and simple addition vs. quantity processing for subtraction and division. Dagenbach and McCloskey (1992) suggest dissociation between arithmetical facts result from a selective damage to segregated memory networks specific for each operation. We will argue that our findings are problematic for Dehaene's model and in good accord with McCloskey's view. PMID:11485063
Mirvish, Ezra D; Shuda, Masahiro
2016-01-01
Over 20% of human cancers worldwide are associated with infectious agents, including viruses, bacteria, and parasites. Various methods have been used to identify human tumor viruses, including electron microscopic observations of viral particles, immunologic screening, cDNA library screening, nucleic acid hybridization, consensus PCR, viral DNA array chip, and representational difference analysis. With the Human Genome Project, a large amount of genetic information from humans and other organisms has accumulated over the last decade. Utilizing the available genetic databases, Feng et al. (2007) developed digital transcriptome subtraction (DTS), an in silico method to sequentially subtract human sequences from tissue or cellular transcriptome, and discovered Merkel cell polyomavirus (MCV) from Merkel cell carcinoma. Here, we review the background and methods underlying the human tumor virus discoveries and explain how DTS was developed and used for the discovery of MCV. PMID:27242703
A moving ship detection based on edge information of single image and background subtraction
NASA Astrophysics Data System (ADS)
Shi, Tingyan; Yang, Lichun; Liu, Zhicheng
2013-10-01
Ship detection based on video is important in the application of surveillance and marine safety, the detection results of tradition methods, such as background subtraction, have much noise because of background noise such as ocean wave. In this paper we present a simple but efficient method for ship detection, It is based on the edge information of single image and movement information of multi images. Firstly, detect those movement pixels used the background subtraction to the video image, and the distance transformation is operation on the difference images; Secondly, we detect the edge of video image used Canny detector , and morphological operation on the edge image, lastly, eliminate the movement pixels if their distance transformation value is bigger than the threshold. The experimental results demonstrate that is efficient to eliminate the background noise and detect the real target.
Soft factor subtraction and transverse momentum dependent parton distributions on the lattice
NASA Astrophysics Data System (ADS)
Ji, Xiangdong; Sun, Peng; Xiong, Xiaonu; Yuan, Feng
2015-04-01
We study the transverse momentum dependent (TMD) parton distributions in the newly proposed quasiparton distribution function framework in Euclidean space. In this framework, the parton distributions can be extracted from lattice observables in a systematic expansion of 1 /Pz where Pz is the hadron momentum. A soft factor subtraction is found to be essential to make the TMDs calculable on the lattice. We show that the quasi-TMDs with the associated soft factor subtraction can be applied in hard QCD scattering processes such as Drell-Yan lepton pair production in hadronic collisions. This allows future lattice calculations to provide information on the nonperturbative inputs and energy evolutions for the TMDs. Extension to the generalized parton distributions and quantum phase space Wigner distributions will lead to a complete nucleon tomography on the lattice.
NASA Astrophysics Data System (ADS)
Badertscher, A.; Curioni, A.; Degunda, U.; Epprecht, L.; Gendotti, A.; Horikawa, S.; Knecht, L.; Lussi, D.; Marchionni, A.; Natterer, G.; Nguyen, K.; Resnati, F.; Rubbia, A.; Viant, T.
2012-08-01
We have operated a liquid-argon large-electron-multiplier time-projection chamber (LAr LEM-TPC) with a large active area of 76 × 40 cm2 and a drift length of 60 cm. This setup represents the largest chamber ever achieved with this novel detector concept. The chamber is equipped with an immersed built-in cryogenic Greinacher multi-stage high-voltage (HV) multiplier, which, when subjected to an external AC HV of ~ 1 kVpp, statically charges up to a voltage a factor of ~ 30 higher inside the LAr vessel, creating a uniform drift field of ~ 0.5 kV/cm over the full drift length. This large LAr LEM-TPC was brought into successful operation in the double-phase (liquid-vapor) operation mode and tested during a period of ~ 1 month, recording impressive three-dimensional images of very high-quality from cosmic particles traversing or interacting in the sensitive volume. The double phase readout and HV systems achieved stable operation in cryogenic conditions demonstrating their good characteristics, which particularly suit applications for next-generation giant-scale LAr-TPCs.
Enhancing shelf life of minimally processed multiplier onion using silicone membrane.
Naik, Ravindra; Ambrose, Dawn C P; Raghavan, G S Vijaya; Annamalai, S J K
2014-12-01
The aim of storage of minimal processed product is to increase the shelf life and thereby extend the period of availability of minimally processed produce. The silicone membrane makes use of the ability of polymer to permit selective passage of gases at different rates according to their physical and chemical properties. Here, the product stored maintains its own atmosphere by the combined effects of respiration process of the commodity and the diffusion rate through the membrane. A study was undertaken to enhance the shelf life of minimally processed multiplier onion with silicone membrane. The respiration activity was recorded at a temperature of 30 ± 2 °C (RH = 60 %) and 5 ± 1 °C (RH = 90 %). The respiration was found to be 23.4, 15.6, 10 mg CO2kg(-1)h(-1) at 5 ± 1 °C and 140, 110, 60 mg CO2kg(-1) h(-1) at 30 ± 2° for the peeled, sliced and diced multiplier onion, respectively. The respiration rate for the fresh multiplier onion was recorded to be 5, 10 mg CO2kg(-1) h(-1) at 5 ± 1 °C and 30 ± 1 ° C, respectively. Based on the shelf life studies and on the sensory evaluation, it was found that only the peeled multiplier onion could be stored. The sliced and diced multiplier onion did not have the required shelf life. The shelf life of the multiplier onion in the peel form could be increased from 4-5 days to 14 days by using the combined effect of silicone membrane (6 cm(2)/kg) and low temperature (5 ± 1 °C). PMID:25477667
Entanglement entropy for free scalar fields in AdS
NASA Astrophysics Data System (ADS)
Sugishita, Sotaro
2016-09-01
We compute entanglement entropy for free massive scalar fields in anti-de Sitter (AdS) space. The entangling surface is a minimal surface whose boundary is a sphere at the boundary of AdS. The entropy can be evaluated from the thermal free energy of the fields on a topological black hole by using the replica method. In odd-dimensional AdS, exact expressions of the Rényi entropy S n are obtained for arbitrary n. We also evaluate 1-loop corrections coming from the scalar fields to holographic entanglement entropy. Applying the results, we compute the leading difference of entanglement entropy between two holographic CFTs related by a renormalization group flow triggered by a double trace deformation. The difference is proportional to the shift of a central charge under the flow.
Asymptotically AdS spacetimes with a timelike Kasner singularity
NASA Astrophysics Data System (ADS)
Ren, Jie
2016-07-01
Exact solutions to Einstein's equations for holographic models are presented and studied. The IR geometry has a timelike cousin of the Kasner singularity, which is the less generic case of the BKL (Belinski-Khalatnikov-Lifshitz) singularity, and the UV is asymptotically AdS. This solution describes a holographic RG flow between them. The solution's appearance is an interpolation between the planar AdS black hole and the AdS soliton. The causality constraint is always satisfied. The entanglement entropy and Wilson loops are discussed. The boundary condition for the current-current correlation function and the Laplacian in the IR is examined. There is no infalling wave in the IR, but instead, there is a normalizable solution in the IR. In a special case, a hyperscaling-violating geometry is obtained after a dimensional reduction.
New massive gravity and AdS(4) counterterms.
Jatkar, Dileep P; Sinha, Aninda
2011-04-29
We show that the recently proposed Dirac-Born-Infeld extension of new massive gravity emerges naturally as a counterterm in four-dimensional anti-de Sitter space (AdS(4)). The resulting on-shell Euclidean action is independent of the cutoff at zero temperature. We also find that the same choice of counterterm gives the usual area law for the AdS(4) Schwarzschild black hole entropy in a cutoff-independent manner. The parameter values of the resulting counterterm action correspond to a c=0 theory in the context of the duality between AdS(3) gravity and two-dimensional conformal field theory. We rewrite this theory in terms of the gauge field that is used to recast 3D gravity as a Chern-Simons theory. PMID:21635026
Detailed ultraviolet asymptotics for AdS scalar field perturbations
NASA Astrophysics Data System (ADS)
Evnin, Oleg; Jai-akson, Puttarak
2016-04-01
We present a range of methods suitable for accurate evaluation of the leading asymptotics for integrals of products of Jacobi polynomials in limits when the degrees of some or all polynomials inside the integral become large. The structures in question have recently emerged in the context of effective descriptions of small amplitude perturbations in anti-de Sitter (AdS) spacetime. The limit of high degree polynomials corresponds in this situation to effective interactions involving extreme short-wavelength modes, whose dynamics is crucial for the turbulent instabilities that determine the ultimate fate of small AdS perturbations. We explicitly apply the relevant asymptotic techniques to the case of a self-interacting probe scalar field in AdS and extract a detailed form of the leading large degree behavior, including closed form analytic expressions for the numerical coefficients appearing in the asymptotics.
Ryang, Seung Ho; Chung, Sam Young; Lee, Sung Hee; Cha, Jae Soon; Yong Kim, Hak; Cho, Tae Ju
2002-12-01
We have developed a subtractive cloning method in which target sequences are effectively enriched by selective adaptor ligation and PCR after hybridization. In this method both tester and driver DNAs are digested with RsaI, ligated with the linker DNA containing a KpnI recognition site, and amplified by PCR. The tester DNA samples are divided into two aliquots, each digested with either RsaI or KpnI. The two DNA samples are then combined and hybridized with an excess of the driver DNA retaining the linker. After hybridization, the DNA mixture is ligated to a new adaptor compatible only with double-stranded tester/tester DNAs. Therefore, only the tester/tester is selectively amplified in subsequent PCR. This also leads to complete elimination of the tester DNA hybridized with driver DNA from the tester DNA population. Although our protocol employs enzymatic treatments, the efficiency of the enzymatic treatments does not affect the subtraction efficiency. This new subtractive enrichment method was applied to isolate Chinese cabbage defense-related genes induced by Pseudomonas syringae pv. tomato (Pst), which elicits a hypersensitive response in Chinese cabbage. After two or three rounds of subtractive hybridization, the sequences of enriched DNAs were determined and examined by BLAST analysis. Northern blot hybridization showed that 12 of the 19 genes analyzed were strongly induced by Pst treatment. Among the 12 Pst-induced genes five represent pathogenesis-related genes encoding PR1a, two chitinases, a thaumatin-like protein, and a PR4 protein. Other Pst-induced genes include two cytochrome P450 genes responsible for glucosinolate biosynthesis, a disease resistance gene homolog, and several genes encoding proteins with unknown functions.
Lavoie, Jean-Pierre; Lefebvre-Lavoie, Josiane; Leclere, Mathilde; Lavoie-Lamoureux, Anouk; Chamberland, Annie; Laprise, Catherine; Lussier, Jacques
2012-01-01
Background Gene expression analyses are used to investigate signaling pathways involved in diseases. In asthma, they have been primarily derived from the analysis of bronchial biopsies harvested from mild to moderate asthmatic subjects and controls. Due to ethical considerations, there is currently limited information on the transcriptome profile of the peripheral lung tissues in asthma. Objective To identify genes contributing to chronic inflammation and remodeling in the peripheral lung tissue of horses with heaves, a naturally occurring asthma-like condition. Methods Eleven adult horses (6 heaves-affected and 5 controls) were studied while horses with heaves were in clinical remission (Pasture), and during disease exacerbation induced by a 30-day natural antigen challenge during stabling (Challenge). Large peripheral lung biopsies were obtained by thoracoscopy at both time points. Using suppression subtractive hybridization (SSH), lung cDNAs of controls (Pasture and Challenge) and asymptomatic heaves-affected horses (Pasture) were subtracted from cDNAs of horses with heaves in clinical exacerbation (Challenge). The differential expression of selected genes of interest was confirmed using quantitative PCR assay. Results Horses with heaves, but not controls, developed airway obstruction when challenged. Nine hundred and fifty cDNA clones isolated from the subtracted library were screened by dot blot array and 224 of those showing the most marked expression differences were sequenced. The gene expression pattern was confirmed by quantitative PCR in 15 of 22 selected genes. Novel genes and genes with an already defined function in asthma were identified in the subtracted cDNA library. Genes of particular interest associated with asthmatic airway inflammation and remodeling included those related to PPP3CB/NFAT, RhoA, and LTB4/GPR44 signaling pathways. Conclusions Pathways representing new possible targets for anti-inflammatory and anti-remodeling therapies for
Digital subtraction myelography for the identification of spontaneous spinal CSF-venous fistulas.
Schievink, Wouter I; Moser, Franklin G; Maya, M Marcel; Prasad, Ravi S
2016-06-01
OBJECTIVE In most patients with spontaneous intracranial hypotension, a spinal CSF leak can be found, but occasionally, no leak can be demonstrated despite extensive spinal imaging. Failure to localize a CSF leak limits treatment options. The authors recently reported the discovery of CSF-venous fistulas in patients with spontaneous intracranial hypotension and now report on the use of digital subtraction myelography in patients with spontaneous intracranial hypotension but no CSF leak identifiable on conventional spinal imaging (i.e., non-digital subtraction myelography). METHODS The patient population consisted of 53 consecutive patients with spontaneous intracranial hypotension who underwent digital subtraction myelography but in whom no spinal CSF leak (i.e., presence of extradural CSF) was identifiable on conventional spinal imaging. RESULTS The mean age of the 33 women and 20 men was 53.4 years (range 29-71 years). A CSF-venous fistula was demonstrated in 10 (19%) of the 53 patients. A CSF-venous fistula was found in 9 (27%) of the 33 women and in 1 (5%) of the 20 men (p = 0.0697). One patient was treated successfully with percutaneous injection of fibrin sealant. Nine patients underwent surgery for the fistula. Surgery resulted in complete resolution of symptoms in 8 patients (follow-up 7-25 months), and in 1 patient, symptoms recurred after 4 months. CONCLUSIONS In this study, the authors found a CSF-venous fistula in approximately one-fifth of the patients with recalcitrant spontaneous intracranial hypotension but no CSF leak identifiable on conventional spinal imaging. The authors suggest that digital subtraction myelography be considered in this patient population. PMID:26849709
Subtractive imaging in confocal scanning microscopy using a CCD camera as a detector.
Sánchez-Ortiga, Emilio; Sheppard, Colin J R; Saavedra, Genaro; Martínez-Corral, Manuel; Doblas, Ana; Calatayud, Arnau
2012-04-01
We report a scheme for the detector system of confocal microscopes in which the pinhole and a large-area detector are substituted by a CCD camera. The numerical integration of the intensities acquired by the active pixels emulates the signal passing through the pinhole. We demonstrate the imaging capability and the optical sectioning of the system. Subtractive-imaging confocal microscopy can be implemented in a simple manner, providing superresolution and improving optical sectioning.
Mantri, Nitin; Olarte, Alexandra; Li, Chun Guang; Xue, Charlie; Pang, Edwin C. K.
2012-01-01
Background Asterids is one of the major plant clades comprising of many commercially important medicinal species. One of the major concerns in medicinal plant industry is adulteration/contamination resulting from misidentification of herbal plants. This study reports the construction and validation of a microarray capable of fingerprinting medicinally important species from the Asterids clade. Methodology/Principal Findings Pooled genomic DNA of 104 non-asterid angiosperm and non-angiosperm species was subtracted from pooled genomic DNA of 67 asterid species. Subsequently, 283 subtracted DNA fragments were used to construct an Asterid-specific array. The validation of Asterid-specific array revealed a high (99.5%) subtraction efficiency. Twenty-five Asterid species (mostly medicinal) representing 20 families and 9 orders within the clade were hybridized onto the array to reveal its level of species discrimination. All these species could be successfully differentiated using their hybridization patterns. A number of species-specific probes were identified for commercially important species like tea, coffee, dandelion, yarrow, motherwort, Japanese honeysuckle, valerian, wild celery, and yerba mate. Thirty-seven polymorphic probes were characterized by sequencing. A large number of probes were novel species-specific probes whilst some of them were from chloroplast region including genes like atpB, rpoB, and ndh that have extensively been used for fingerprinting and phylogenetic analysis of plants. Conclusions/Significance Subtracted Diversity Array technique is highly efficient in fingerprinting species with little or no genomic information. The Asterid-specific array could fingerprint all 25 species assessed including three species that were not used in constructing the array. This study validates the use of chloroplast genes for bar-coding (fingerprinting) plant species. In addition, this method allowed detection of several new loci that can be explored to solve
Temporal subtraction system on torso FDG-PET scans based on statistical image analysis
NASA Astrophysics Data System (ADS)
Shimizu, Yusuke; Hara, Takeshi; Fukuoka, Daisuke; Zhou, Xiangrong; Muramatsu, Chisako; Ito, Satoshi; Hakozaki, Kenta; Kumita, Shin-ichiro; Ishihara, Kei-ichi; Katafuchi, Tetsuro; Fujita, Hiroshi
2013-02-01
Diagnostic imaging on FDG-PET scans was often used to evaluate chemotherapy results of cancer patients. Radiologists compare the changes of lesions' activities between previous and current examinations for the evaluation. The purpose of this study was to develop a new computer-aided detection (CAD) system with temporal subtraction technique for FDGPET scans and to show the fundamental usefulness based on an observer performance study. Z-score mapping based on statistical image analysis was newly applied to the temporal subtraction technique. The subtraction images can be obtained based on the anatomical standardization results because all of the patients' scans were deformed into standard body shape. An observer study was performed without and with computer outputs to evaluate the usefulness of the scheme by ROC (receiver operating characteristics) analysis. Readers responded as confidence levels on a continuous scale from absolutely no change to definitely change between two examinations. The recognition performance of the computer outputs for the 43 pairs was 96% sensitivity with 31.1 false-positive marks per scan. The average of area-under-the-ROC-curve (AUC) from 4 readers in the observer performance study was increased from 0.85 without computer outputs to 0.90 with computer outputs (p=0.0389, DBM-MRMC). The average of interpretation time was slightly decreased from 42.11 to 40.04 seconds per case (p=0.625, Wilcoxon test). We concluded that the CAD system for torso FDG-PET scans with temporal subtraction technique might improve the diagnostic accuracy of radiologist in cancer therapy evaluation.
Background matrix subtraction (BMS): A novel background removal algorithm for GPR data
NASA Astrophysics Data System (ADS)
Rashed, Mohamed; Harbi, Hussein
2014-07-01
Background noise is a common type of coherent noise that severely compromises the integrity of the high-resolution images provided by ground penetrating radar survey. Several existing techniques employ different approaches to attenuate background noise. In this study, we present the background matrix subtraction (BMS) as an alternative technique to remove horizontal background noise and we compare its efficiency to that of the conventional background removal technique. Instead of calculating an average trace that is subtracted from the GPR data in the conventional background removal methods, the BMS technique is based on calculating a complete background matrix of the same size of the GPR section. The background matrix is created through a series of windowing, sample exclusion, weighting, and iteration. This series of processes guarantees that the background matrix is least affected by target response and is composed purely of horizontal background noise. The computed background matrix is then subtracted from the GPR data to remove horizontal events. Results of experiments conducted on both synthetic and real GPR data show that the BMS technique yields better results than the commonly used background removal technique.
Removing ECG Artifact from the Surface EMG Signal Using Adaptive Subtraction Technique
Abbaspour, S; Fallah, A
2014-01-01
Background: The electrocardiogram artifact is a major contamination in the electromyogram signals when electromyogram signal is recorded from upper trunk muscles and because of that the contaminated electromyogram is not useful. Objective: Removing electrocardiogram contamination from electromyogram signals. Methods: In this paper, the clean electromyogram signal, electrocardiogram artifact and electrocardiogram signal were recorded from leg muscles, the pectoralis major muscle of the left side and V4, respectively. After the pre-processing, contaminated electromyogram signal is simulated with a combination of clean electromyogram and electrocardiogram artifact. Then, contaminated electromyogram is cleaned using adaptive subtraction method. This method contains some steps; (1) QRS detection, (2) formation of electrocardiogram template by averaging the electrocardiogram complexes, (3) using low pass filter to remove undesirable artifacts, (4) subtraction. Results: Performance of our method is evaluated using qualitative criteria, power spectrum density and coherence and quantitative criteria signal to noise ratio, relative error and cross correlation. The result of signal to noise ratio, relative error and cross correlation is equal to 10.493, 0.04 and %97 respectively. Finally, there is a comparison between proposed method and some existing methods. Conclusion: The result indicates that adaptive subtraction method is somewhat effective to remove electrocardiogram artifact from contaminated electromyogram signal and has an acceptable result. PMID:25505766
The use of procedural knowledge in simple addition and subtraction problems.
Fayol, Michel; Thevenot, Catherine
2012-06-01
In a first experiment, adults were asked to solve one-digit additions, subtractions and multiplications. When the sign appeared 150 ms before the operands, addition and subtraction were solved faster than when the sign and the operands appeared simultaneously on screen. This priming effect was not observed for multiplication problems. A second experiment replicates these results on addition and multiplication and, moreover, shows that the priming effect in addition is observed for all problems, including very small ones such as 4+3. In fact, the only problems that were not primed by the addition sign were tie problems, which confirms that they have a special status in memory. Taken together, these results suggest that abstract procedures are pre-activated by the addition and subtraction signs and that these procedures are consequently used by adults to solve the problems. No such procedures would be pre-activated for multiplication, which are then most probably solved by retrieval of the result from memory. Moreover, while obviously two different strategies were used by individuals in order to solve addition and multiplication, solution times were similar when the problems were presented in their whole. These results, which question most of the conclusions of the current literature, support Anderson's model (1982) and Baroody's assumptions (1983) on the existence of compacted procedures that could be as fast as retrievals. PMID:22405923
Brown, K.A.; Benoit, L.; Clements, J.P.; Wackers, F.J.
1987-06-01
A recent report described a pattern of reverse redistribution on poststreptokinase /sup 201/Tl studies which was believed to be due to rapid washout of /sup 201/Tl from the infarct area related to reperfusion of the infarct vessel. We have also observed the phenomenon of rapid washout of /sup 201/Tl from the area of infarction in the absence of thrombolytic therapy. This study was undertaken to test the hypothesis that rapid washout of /sup 201/Tl from an area of infarction is an artifact of background subtraction usually employed in analysis of washout. A total of 61 patients with previous myocardial infarction who underwent cardiac catheterization and exercise /sup 201/Tl imaging were examined. Thallium-201 images were analyzed using a validated quantitative method employing interpolative background correction. Abnormally increased /sup 201/Tl washout was noted in 11 infarct segments in 10 (18%) patients. Infarct segments with rapid washout had significantly less initial uptake, and more severe associated wall motion abnormalities than infarct segments with normal washout. When quantitative analysis was repeated without background subtraction, no segments with rapid washout were observed. A phantom model was constructed to further test our hypothesis. The frequency of observed rapid washout was directly related to the severity of the initial defect and was entirely dependent upon utilizing background correction during the quantitative analysis. Our study suggests that rapid washout of /sup 201/Tl in an area of previous infarction reflects an artifact of background subtraction involved with standard quantitative analysis.
Shrestha, Vivek R; Lee, Sang-Shin; Kim, Eun-Soo; Choi, Duk-Yong
2014-11-12
Nanophotonic devices enabled by aluminum plasmonics are saliently advantageous in terms of their low cost, outstanding sustainability, and affordable volume production. We report, for the first time, aluminum plasmonics based highly transmissive polarization-independent subtractive color filters, which are fabricated just with single step electron-beam lithography. The filters feature selective suppression in the transmission spectra, which is realized by combining the propagating and nonpropagating surface plasmons mediated by an array of opaque and physically thin aluminum nanopatches. A broad palette of bright, high-contrast subtractive colors is successfully demonstrated by simply varying the pitches of the nanopatches. These subtractive color filters have twice the photon throughput of additive counterparts, ultimately providing elevated optical transmission and thus stronger color signals. Moreover, the filters are demonstrated to conspicuously feature a dual-mode operation, both transmissive and reflective, in conjunction with a capability to exhibit micron-scale colors in arbitrary shapes. They are anticipated to be diversely applied to digital display, digital imaging, color printing, and sensing.
Can approximate mental calculation account for operational momentum in addition and subtraction?
Knops, André; Dehaene, Stanislas; Berteletti, Ilaria; Zorzi, Marco
2014-01-01
The operational momentum (OM) effect describes a cognitive bias whereby we overestimate the results of mental addition problems while underestimating for subtraction. To test whether the OM emerges from psychophysical characteristics of the mental magnitude representation we measured two basic parameters (Weber fraction and numerical estimation accuracy) characterizing the mental magnitude representation and participants' performance in cross-notational addition and subtraction problems. Although participants were able to solve the cross-notational problems, they consistently chose relatively larger results in addition problems than in subtraction problems, thus replicating and extending previous results. Combining the above measures in a psychophysical model allowed us to partially predict the chosen results. Most crucially, however, we were not able to fully model the OM bias on the basis of these psychophysical parameters. Our results speak against the idea that the OM is due to basic characteristics of the mental magnitude representation. In turn, this might be interpreted as evidence for the assumption that the OM effect is better explained by attentional shifts along the mental magnitude representation during mental calculation. PMID:24499435
Holography and AdS4 self-gravitating dyons
NASA Astrophysics Data System (ADS)
Lugo, A. R.; Moreno, E. F.; Schaposnik, F. A.
2010-11-01
We present a self-gravitating dyon solution of the Einstein-Yang-Mills-Higgs equations of motion in asymptotically AdS space. The back reaction of gauge and Higgs fields on the space-time geometry leads to the metric of an asymptotically AdS black hole. Using the gauge/gravity correspondence we analyze relevant properties of the finite temperature quantum field theory defined on the boundary. In particular we identify an order operator, characterize a phase transition of the dual theory on the border and also compute the expectation value of the finite temperature Wilson loop.
AdS box graphs, unitarity and operator product expansions
NASA Astrophysics Data System (ADS)
Hoffmann, L.; Mesref, L.; Rühl, W.
2000-11-01
We develop a method of singularity analysis for conformal graphs which, in particular, is applicable to the holographic image of AdS supergravity theory. It can be used to determine the critical exponents for any such graph in a given channel. These exponents determine the towers of conformal blocks that are exchanged in this channel. We analyze the scalar AdS box graph and show that it has the same critical exponents as the corresponding CFT box graph. Thus pairs of external fields couple to the same exchanged conformal blocks in both theories. This is looked upon as a general structural argument supporting the Maldacena hypothesis.
Phases of global AdS black holes
NASA Astrophysics Data System (ADS)
Basu, Pallab; Krishnan, Chethan; Subramanian, P. N. Bala
2016-06-01
We study the phases of gravity coupled to a charged scalar and gauge field in an asymptotically Anti-de Sitter spacetime ( AdS 4) in the grand canonical ensemble. For the conformally coupled scalar, an intricate phase diagram is charted out between the four relevant solutions: global AdS, boson star, Reissner-Nordstrom black hole and the hairy black hole. The nature of the phase diagram undergoes qualitative changes as the charge of the scalar is changed, which we discuss. We also discuss the new features that arise in the extremal limit.
ERIC Educational Resources Information Center
Hillen, Amy F.; Watanabe, Tad
2013-01-01
Recent documents suggest that all students, even young children, should have opportunities to engage in reasoning and proof (CCSSI 2010; NCTM 2000, 2006, 2009). One mathematical practice that is central to reasoning and proof is making conjectures (CCSSI 2010; NCTM 2000; Stylianides 2008). In the elementary grades, "formulating conjectures…
NASA Astrophysics Data System (ADS)
Turco, M.; Milelli, M.
2009-09-01
skill scores of two competitive forecast. It is important to underline that the conclusions refer to the analysis of the Piemonte operational alert system, so they cannot be directly taken as universally true. But we think that some of the main lessons that can be derived from this study could be useful for the meteorological community. In details, the main conclusions are the following: - despite the overall improvement in global scale and the fact that the resolution of the limited area models has increased considerably over recent years, the QPF produced by the meteorological models involved in this study has not improved enough to allow its direct use, that is, the subjective HQPF continues to offer the best performance; - in the forecast process, the step where humans have the largest added value with respect to mathematical models, is the communication. In fact the human characterisation and communication of the forecast uncertainty to end users cannot be replaced by any computer code; - eventually, although there is no novelty in this study, we would like to show that the correct application of appropriated statistical techniques permits a better definition and quantification of the errors and, mostly important, allows a correct (unbiased) communication between forecasters and decision makers.
Multiply periodic states and isolated skyrmions in an anisotropic frustrated magnet
Leonov, A. O.; Mostovoy, M.
2015-01-01
Multiply periodic states appear in a wide variety of physical contexts, such as the Rayleigh–Bénard convection, Faraday waves, liquid crystals and skyrmion crystals recently observed in chiral magnets. Here we study the phase diagram of an anisotropic frustrated magnet which contains five different multiply periodic states including the skyrmion crystal. We clarify the mechanism for stabilization of these states and discuss how they can be observed in magnetic resonance and electric polarization measurements. We also find stable isolated skyrmions with topological charge 1 and 2. Their spin structure, interactions and dynamics are more complex than those in chiral magnets. In particular, magnetic resonance in the skyrmion crystal should be accompanied by oscillations of the electric polarization with a frequency depending on the amplitude of the a.c. magnetic field. These results show that skyrmion materials with rich physical properties can be found among frustrated magnets. We formulate rules to help the search. PMID:26394924
Gain Characteristics of a 100 μm thick Gas Electron Multiplier (GEM)
NASA Astrophysics Data System (ADS)
Mir, J. A.; Natal da Luz, H.; Carvalho, X.; Azevedo, C. D. R.; dos Santos, J. M. F.; Amaro, F. D.
2015-12-01
The standard Gas Electron Multiplier (GEM) invented by F. Sauli [1] consists of high density holes etched in 50 μm thick copper clad Kapton foil. This study, however, investigated the basic charge gain characteristics of a non-standard 100 μm thick Gas Electron Multiplier, fabricated using the same wet chemical etch process at CERN. It was possible to sustain charge gains of 3× 103 and 1× 104 using single and double stage configurations, respectively, operated in an Ar(70%)-CO2(30%) gas mixture. These values are similar to those achieved with standard GEMs. Crucially, we found that the thicker GEM is more robust as it withstood sparking without catastrophic failure. We also measured the gain dependence on ambient variables such as pressure and temperature and found the gain sensitivity to be 4.0 K/mbar, compared with 1.55 K/mbar for the standard GEM.
Density functional theory study of multiply ionized weakly bound fullerene dimers.
Zettergren, Henning; Wang, Yang; Lamsabhi, Al Mokhtar; Alcamí, Manuel; Martín, Fernando
2009-06-14
Multiply ionized fullerene dimers ([C(60)](2) (q+),q=1-6) have been studied by means of state-of-the-art density functional theory methods. We found that the singly charged dimer is more strongly bound than the corresponding neutral van der Waals dimer at the binding distance of the latter; in contrast, multiply charged dimers (q>or=2) are unstable. For the latter dimers, the calculated kinetic energy release in the binary fission yielding intact fullerenes is lower than those reported in recent experimental work. This implies that, in such experiments, there are significant internal excitations in the separating monomers. We also show that electron transfer within the charged dimers occurs on the subfemtosecond time scale, in accordance with the high charge mobility observed in dimers and larger clusters of fullerenes. This provides an explanation for the even-odd effects in the measured multiple ionization yields of fullerene dimers.
Effects of layer-multiplying and interface on the content of β-transcrystallization in PP
Lei, Fan; Li, Jiang E-mail: nic7702@scu.edu.cn; Guo, Shaoyun E-mail: nic7702@scu.edu.cn
2015-05-22
The alternating multilayered polypropylene (PP layer)/β-nucleating agent filled-polypropylene (β-PP layer) were prepared through layer-multiplying extrusion combined with an assembly of layer-multiplying elements (LM Es). The content of β-crystal was firstly evaluated by differential scanning calorimetry (DSC), which indicated that the relative amount of the β-crystal increased from 38.67% to 81.22% with the increase of layer numbers from 2-layer to 128-layer. It was well consistent with the results of X-ray diffraction (XRD). The morphology observation of β-crystal by polarizing microscope (POM) revealed that the closely packed nuclei in the interface could induce numerous β-transcrystallization in pure PP layer due to the confinement effect. The non-isothermal crystallization kinetic analysis via Mozhishen’s methods manifested that the crystallization rate was greatly enhanced by the augment of the layered interface.
Feng, Danqi; Xie, Heng; Chen, Guodong; Qian, Lifen; Sun, Junqiang
2014-07-28
We demonstrate a photonic approach to simultaneously realize a frequency-multiplied and phase-shifted microwave signal based on the birefringence effects in the high nonlinear fiber. The phase shift caused by asymmetric variations in refractive indexes of fiber between two orthogonal polarization states is introduced into two coherent harmonic of the modulated signals. By beating the phase-modulated sidebands, a frequency-multiplied microwave signal is generated and its phase can be adjusted by simply controlling the pump power. A microwave signal at doubled- or quadrupled-frequency with a full 2π phase shift is obtained over a frequency range from 10 GHz to 30 GHz. The proposed approach has the potential applications in the system with larger-broadband, higher-frequency and -data-rate system, even to handle a multi-wavelength operation.
On-Chip Power-Combining for High-Power Schottky Diode-Based Frequency Multipliers
NASA Technical Reports Server (NTRS)
Chattopadhyay, Goutam; Mehdi, Imran; Schlecht, Erich T.; Lee, Choonsup; Siles, Jose V.; Maestrini, Alain E.; Thomas, Bertrand; Jung, Cecile D.
2013-01-01
A 1.6-THz power-combined Schottky frequency tripler was designed to handle approximately 30 mW input power. The design of Schottky-based triplers at this frequency range is mainly constrained by the shrinkage of the waveguide dimensions with frequency and the minimum diode mesa sizes, which limits the maximum number of diodes that can be placed on the chip to no more than two. Hence, multiple-chip power-combined schemes become necessary to increase the power-handling capabilities of high-frequency multipliers. The design presented here overcomes difficulties by performing the power-combining directly on-chip. Four E-probes are located at a single input waveguide in order to equally pump four multiplying structures (featuring two diodes each). The produced output power is then recombined at the output using the same concept.
NASA Astrophysics Data System (ADS)
Kitipornchai, S.; Xiang, Y.; Liew, K. M.
1994-06-01
This paper presents the first known solutions of the problem of free flexural vibration of corner supported Mindlin plates of arbitrary shape. A hybrid numerical approach combining the Rayleigh-Ritz method and the Lagrange multiplier method has been developed to solve the plate vibration problem. The algorithm uses the pb-2 shape functions to account for different geometries, and Lagrange multipliers to impose zero lateral deflection constraints at plate corners. The method of solution is applicable to arbitrarily shaped plates with corner supports. In this paper, however, only triangular, skew and annular sector plates are chosen for the purpose of demonstration. Some comparison studies for corner supported thin square plates are made to verify the accuracy of the derived solutions.
Prompt and delayed fragmentation of bromouracil cations ionized by multiply charged ions
NASA Astrophysics Data System (ADS)
Delaunay, Rudy; Champeaux, Jean-Philippe; Maclot, Sylvain; Capron, Michael; Domaracka, Alicja; Méry, Alain; Manil, Bruno; Adoui, Lamri; Rousseau, Patrick; Moretto-Capelle, Patrick; Huber, Bernd A.
2014-06-01
The fragmentation of singly and multiply charged 5-bromouracil molecules (C4H3N2O2Br) induced by collisions with slow multiply charged ions has been studied. The emission of neutral fragments as well as charge separating decay channels are identified as a function of the projectile charge state. In the first case, delayed loss of neutral moieties, occurring on a μs time scale, indicates a wider internal energy distribution resulting in a power law decay. In the second case, the most important decay channels, leading to the formation of Br+, HNCO+ and CO+/NHCH+, are discussed showing that in many processes intramolecular H-migration occurs before fragmentation. Furthermore, molecular rearrangement may lead to delayed charge separating processes. Although the dication of bromouracil is unstable, smaller doubly charged systems created by the loss of neutral fragments are found to be (meta) stable.
Noise limitations of multiplier phototubes in the radiation environment of space
NASA Technical Reports Server (NTRS)
Viehmann, W.; Eubanks, A. G.
1976-01-01
The contributions of Cerenkov emission, luminescence, secondary electron emission, and bremsstrahlung to radiation-induced data current and noise of multiplier phototubes were analyzed quantitatively. Fluorescence and Cerenkov emission in the tube window are the major contributors and can quantitatively account for dark count levels observed in orbit. Radiation-induced noise can be minimized by shielding, tube selection, and mode of operation. Optical decoupling of windows and cathode (side-window tubes) leads to further reduction of radiation-induced dark counts, as does reducing the window thickness and effective cathode area, and selection of window/cathode combinations of low fluorescence efficiency. In trapped radiation-free regions of near-earth orbits and in free space, Cerenkov emission by relativistic particles contributes predominantly to the photoelectron yield per event. Operating multiplier phototubes in the photon (pulse) counting mode will discriminate against these large pulses and substantially reduce the dark count and noise to levels determined by fluorescence.
ERIC Educational Resources Information Center
Shumway, Jessica F.; Kyriopoulos, Joan
2014-01-01
Being able to find the correct answer to a math problem does not always indicate solid mathematics mastery. A student who knows how to apply the basic algorithms can correctly solve problems without understanding the relationships between numbers or why the algorithms work. The Common Core standards require that students actually understand…
Rosado-Méndez, I; Palma, B A; Brandan, M E
2008-12-01
Contrast-medium-enhanced digital mammography (CEDM) is an image subtraction technique which might help unmasking lesions embedded in very dense breasts. Previous works have stated the feasibility of CEDM and the imperative need of radiological optimization. This work presents an extension of a former analytical formalism to predict contrast-to-noise ratio (CNR) in subtracted mammograms. The goal is to optimize radiological parameters available in a clinical mammographic unit (x-ray tube anode/filter combination, voltage, and loading) by maximizing CNR and minimizing total mean glandular dose (D(gT)), simulating the experimental application of an iodine-based contrast medium and the image subtraction under dual-energy nontemporal, and single- or dual-energy temporal modalities. Total breast-entrance air kerma is limited to a fixed 8.76 mGy (1 R, similar to screening studies). Mathematical expressions obtained from the formalism are evaluated using computed mammographic x-ray spectra attenuated by an adipose/glandular breast containing an elongated structure filled with an iodinated solution in various concentrations. A systematic study of contrast, its associated variance, and CNR for different spectral combinations is performed, concluding in the proposal of optimum x-ray spectra. The linearity between contrast in subtracted images and iodine mass thickness is proven, including the determination of iodine visualization limits based on Rose's detection criterion. Finally, total breast-entrance air kerma is distributed between both images in various proportions in order to maximize the figure of merit CNR2/D(gT). Predicted results indicate the advantage of temporal subtraction (either single- or dual-energy modalities) with optimum parameters corresponding to high-voltage, strongly hardened Rh/Rh spectra. For temporal techniques, CNR was found to depend mostly on the energy of the iodinated image, and thus reduction in D(gT) could be achieved if the spectral energy
Porphyromonas gingivalis FDC381 multiplies and persists within human oral epithelial cells in vitro.
Madianos, P N; Papapanou, P N; Nannmark, U; Dahlén, G; Sandros, J
1996-01-01
Porphyromonas gingivalis FDC381 replication and persistence within KB epithelial cells in vitro were studied by means of an antibiotic protection assay and electron microscopy. Intracellular counts decreased during the first 24 h; showed a threefold increase during the second day, indicating intracellular multiplication; and after 8 days declined to levels approximating 40% of the initial invasion. The ability of P. gingivalis to persist and multiply within epithelial cells may constitute a pathogenic mechanism in periodontal disease. PMID:8550223
Frequency multiplying oscillator with an electron beam accelerated in a drift space
Jang, Kyu-Ha; Lee, Kitae; Hee Park, Seong; Uk Jeong, Young; Miginsky, S.
2012-07-02
In a uniform acceleration region, the behavior of a velocity-modulated electron beam has been analyzed using a particle-in-cell code. By making use of one of the accelerated harmonic components of the velocity-modulated electron beam, we demonstrate a frequency multiplying oscillator for a compact THz emitter, which employs multiple electron beams and a higher order mode resonator to modulate the electron beam without an additional driving source.
Efficiency and weight of voltage multiplier type ultra lightweight dc-dc converters
NASA Technical Reports Server (NTRS)
Harrigill, W. T., Jr.; Myers, I. T.
1975-01-01
An analytical and experimental study was made of a capacitor-diode voltage multiplier without a transformer which offers the possibility of high efficiency with light weight. The dc-dc conversion efficiencies of about 94 percent were achieved at output powers of 150 watts at 1000 volts using 8x multiplication. A detailed identification of losses was made, including forward drop losses in component, switching losses, reverse junction capacitance charging losses, and charging losses in the main ladder capacitors.
Efficiency and weight of voltage multiplier type ultra lightweight d.c.-d.c. converters
NASA Technical Reports Server (NTRS)
Harrigill, W. T., Jr.; Myers, I. T.
1975-01-01
This paper presents an analytical and experimental study of a capacitor-diode voltage multiplier without a transformer which offers the possibility of high efficiency with light weight. Dc-dc conversion efficiencies of about 94% were achieved at output powers of 150 watts at 1000 volts using 8x multiplication. A detailed identification of losses was made, including forward drop losses in component, switching losses, reverse junction capacitance charging losses, and charging losses in the main ladder capacitors.
Borrero, Carrie S W; Vollmer, Timothy R
2006-01-01
We evaluated interventions designed to reduce multiply controlled problem behavior exhibited by a young boy with developmental disabilities, using a multiple baseline design. Each intervention was designed to address a specific social function of problem behavior. Results showed that the separate interventions were useful in reducing problem behavior, and terminal schedules were reached by way of schedule thinning (attention condition) and delays to reinforcement (tangible and escape conditions). PMID:17020218
Low-order-mode harmonic multiplying gyrotron traveling-wave amplifier in W band
NASA Astrophysics Data System (ADS)
Yeh, Y. S.; Hung, C. L.; Chang, T. H.; Chen, C. H.; Yang, S. J.; Lai, C. H.; Lin, T. Y.; Lo, Y. C.; Hong, J. W.
2012-09-01
Harmonic multiplying gyrotron traveling-wave amplifiers (gyro-TWAs) allow for magnetic field reduction and frequency multiplication. To avoid absolute instabilities, this work proposes a W-band harmonic multiplying gyro-TWA operating at low-order modes. By amplifying a fundamental harmonic TE11 drive wave, the second harmonic component of the beam current initiates a TE21 wave to be amplified. Absolute instabilities in the gyro-TWA are suppressed by shortening the interaction circuit and increasing wall losses. Simulation results reveal that compared with Ka-band gyro-TWTs, the lower wall losses effectively suppress absolute instabilities in the W-band gyro-TWA. However, a global reflective oscillation occurs as the wall losses decrease. Increasing the length or resistivity of the lossy section can reduce the feedback of the oscillation to stabilize the amplifier. The W-band harmonic multiplying gyro-TWA is predicted to yield a peak output power of 111 kW at 98 GHz with an efficiency of 25%, a saturated gain of 26 dB, and a bandwidth of 1.6 GHz for a 60 kV, 7.5 A electron beam with an axial velocity spread of 8%.
NASA Astrophysics Data System (ADS)
de Schryver, C.; Weithoffer, S.; Wasenmüller, U.; Wehn, N.
2012-09-01
Channel coding is a standard technique in all wireless communication systems. In addition to the typically employed methods like convolutional coding, turbo coding or low density parity check (LDPC) coding, algebraic codes are used in many cases. For example, outer BCH coding is applied in the DVB-S2 standard for satellite TV broadcasting. A key operation for BCH and the related Reed-Solomon codes are multiplications in finite fields (Galois Fields), where extension fields of prime fields are used. A lot of architectures for multiplications in finite fields have been published over the last decades. This paper examines four different multiplier architectures in detail that offer the potential for very high throughputs. We investigate the implementation performance of these multipliers on FPGA technology in the context of channel coding. We study the efficiency of the multipliers with respect to area, frequency and throughput, as well as configurability and scalability. The implementation data of the fully verified circuits are provided for a Xilinx Virtex-4 device after place and route.
G-band harmonic multiplying gyrotron traveling-wave amplifier with a mode-selective circuit
Yeh, Y. S.; Chen, Chang-Hong; Wang, Z. W.; Kao, B. H.; Chen, Chien-Hsiang; Lin, T. Y.; Guo, Y. W.
2014-12-15
Harmonic multiplying gyrotron traveling-wave amplifiers (gyro-TWAs) permit for magnetic field reduction and frequency multiplication. A high-order-mode harmonic multiplying gyro-TWA with large circuit dimensions and low ohmic loss can achieve a high average power. By amplifying a fundamental harmonic TE{sub 01} drive wave, the second harmonic component of the beam current initiates a TE{sub 02} wave to be amplified. Wall losses can suppress some competing modes because they act as an effective sink of the energy of the modes. However, such wall losses do not suppress all competing modes as the fields are contracted in the copper section in the gyro-TWA. An improved mode-selective circuit, using circular waveguides with the specified radii, can provide the rejection points within the frequency range to suppress the competing modes. The simulated results reveal that the mode-selective circuit can provide an attenuation of more than 10 dB to suppress the competing modes (TE{sub 21}, TE{sub 51}, TE{sub 22}, and TE{sub 03}). A G-band second harmonic multiplying gyro-TWA with the mode-selective circuit is predicted to yield a peak output power of 50 kW at 198.8 GHz, corresponding to a saturated gain of 55 dB at an interaction efficiency of 10%. The full width at half maximum bandwidth is 5 GHz.
Precision improvement of the current multiplier based on the quantum current-mirror effect
NASA Astrophysics Data System (ADS)
Takeda, Kouichi; Ishida, Chihiro; Gandrothula, Srinivas; Mizugaki, Yoshinao; Shimada, Hiroshi
2014-02-01
The relationship between the coupling strength and the uncertainty in current duplication was investigated for the quantum current-mirror effect in capacitively coupled arrays of small Josephson junctions. With the increase in the coupling factor κ, defined as \\kappa \\equiv C_{\\text{c}}/C, with Cc being the coupling capacitance and C the capacitance of the junction, the uncertainty decreased rapidly, especially at \\kappa > 1, and the standard deviation of the error reached as low as the order of 10 fA at \\kappa \\simeq 2.4. On this basis, we fabricated a 10-fold current multiplier composed of 11 simple arrays of junctions coupled more strongly (\\kappa \\simeq 0.5), using a plate-capacitor structure, than a previously studied multiplier (\\kappa \\simeq 0.01). It demonstrated more precise current-multiplication behavior than the previous multiplier with no intentional coupling structure, and the standard deviation of the error in current multiplication was decreased to less than 1/10 of the previous result.
On the origin of multiply-impulsive emission from solar flares. Ph.D. Thesis
NASA Technical Reports Server (NTRS)
Karpen, J. T.
1980-01-01
A set of solar hard X-ray bursts observed with the hard X-ray burst spectrometer on board the OSO-5 satellite was analyzed. The multiply-impulsive two stage events were selected on the basis of both morphological characteristics and association with appropriate phenomena at other wavelengths. Coincident radio, soft X-ray, H-alpha interplanetary particle, and magnetographic data were obtained from several observatories, to aid in developing a comprehensive picture of the physical processes underlying these complex bursts. Two classes of multiply impulsive bursts were identified: events whose components spikes apparently originate in one location, and events in which groups of spikes appear to come from separate regions which flare sequentially. The origin of multiplicity in the case of a single source region remains unidentified. Purely impulsive emissions show no sign of betatron acceleration, thus eliminating this mechanisn as a candidate for inducing multiply spiked structure. The majority of the two stage bursts, however, exhibited spectral behavior consistent with the betatron model, for the first few minutes of the second stage. Betatron acceleration thus has been identified as a common second stage phenomenon.
Design of multiplier-less minimum-phase filters based on sharpening compensated comb filters
NASA Astrophysics Data System (ADS)
Jovanovic Dolecek, Gordana
2016-08-01
Minimum-phase (MP) filters have all zeros inside and/or unit circle. As a consequence, the group delay of an MP system is always less than that of non-minimum phase systems, having the equal magnitude responses. Minimum-phase (MP) filters find applications where it is necessary to have a low group delay, like in communications, speech processing, and predictive coding, among others. This paper presents a novel simple method for the direct design of low-pass minimum-phase (MP) filters. Method is based on design of two compensated combs, using a multiplier-less minimum-phase compensator, and sharpening technique. The first comb defines the stop band and pass band of the MP filter, while the second comb decreases side lobes of the first comb, thus increasing attenuation of the resulting MP filter. Knowing that all zeros of comb filter are on the unit circle, the compensated comb is also a MP filter. Similarly, under the special condition, the sharpening of multiplier-less compensated comb may also result in a MP multiplier-less filter. The benefit of the proposed method is illustrated in the provided design examples.
NASA Astrophysics Data System (ADS)
Rivera, Christian A.; Heniche, Mourad; Glowinski, Roland; Tanguy, Philippe A.
2010-07-01
A parallel approach to solve three-dimensional viscous incompressible fluid flow problems using discontinuous pressure finite elements and a Lagrange multiplier technique is presented. The strategy is based on non-overlapping domain decomposition methods, and Lagrange multipliers are used to enforce continuity at the boundaries between subdomains. The novelty of the work is the coupled approach for solving the velocity-pressure-Lagrange multiplier algebraic system of the discrete Navier-Stokes equations by a distributed memory parallel ILU (0) preconditioned Krylov method. A penalty function on the interface constraints equations is introduced to avoid the failure of the ILU factorization algorithm. To ensure portability of the code, a message based memory distributed model with MPI is employed. The method has been tested over different benchmark cases such as the lid-driven cavity and pipe flow with unstructured tetrahedral grids. It is found that the partition algorithm and the order of the physical variables are central to parallelization performance. A speed-up in the range of 5-13 is obtained with 16 processors. Finally, the algorithm is tested over an industrial case using up to 128 processors. In considering the literature, the obtained speed-ups on distributed and shared memory computers are found very competitive.
Solving short-term electric hydrothermal scheduling problems by exponential multiplier methods
NASA Astrophysics Data System (ADS)
Mijangos, Eugenio
2008-06-01
The short-term electric hydrothermal scheduling (STEHS) problem consists in optimizing the production of hydro and thermal electric generation units over a short time period (up to one week long). The problem described in this work can be modelled as a nonlinear network flow problem with linear and nonlinear side constraints. The minimization of this kind of problem can be performed by exploiting the efficiency of network flow techniques. It lies in minimizing approximately a series of augmented Lagrangian functions including only the side constraints, subject to balance constraints in the nodes and capacity bounds. One of the drawbacks of the multiplier methods with quadratic penalty function is that the augmented Lagrangian is not twice differentiable when it is applied to problems with inequality constraints. This article overcomes this difficulty by using the exponential multiplier method. In order to improve the performance some parameters are tuned. The efficiency of this method over STEHS test problems is illustrated by comparing its CPU-times with those of the quadratic multiplier method and with those of the general purpose codes MINOS, SNOPT, and KNITRO. Numerical results are promising.
D-branes on AdS flux compactifications
NASA Astrophysics Data System (ADS)
Koerber, Paul; Martucci, Luca
2008-01-01
We study D-branes in Script N = 1 flux compactifications to AdS4. We derive their supersymmetry conditions and express them in terms of background generalized calibrations. Basically because AdS has a boundary, the analysis of stability is more subtle and qualitatively different from the usual case of Minkowski compactifications. For instance, stable D-branes filling AdS4 may wrap trivial internal cycles. Our analysis gives a geometric realization of the four-dimensional field theory approach of Freedman and collaborators. Furthermore, the one-to-one correspondence between the supersymmetry conditions of the background and the existence of generalized calibrations for D-branes is clarified and extended to any supersymmetric flux background that admits a time-like Killing vector and for which all fields are time-independent with respect to the associated time. As explicit examples, we discuss supersymmetric D-branes on IIA nearly Kähler AdS4 flux compactifications.
Dyonic AdS black holes from magnetohydrodynamics
NASA Astrophysics Data System (ADS)
Caldarelli, Marco M.; Dias, Óscar J. C.; Klemm, Dietmar
2009-03-01
We use the AdS/CFT correspondence to argue that large dyonic black holes in anti-de Sitter spacetime are dual to stationary solutions of the equations of relativistic magnetohydrodynamics on the conformal boundary of AdS. The dyonic Kerr-Newman-AdS4 solution corresponds to a charged diamagnetic fluid not subject to any net Lorentz force, due to orthogonal magnetic and electric fields compensating each other. The conserved charges, stress tensor and R-current of the fluid are shown to be in exact agreement with the corresponding quantities of the black hole. Furthermore, we obtain stationary solutions of the Navier-Stokes equations in four dimensions, which yield predictions for (yet to be constructed) charged rotating black strings in AdS5 carrying nonvanishing momentum along the string. Finally, we consider Scherk-Schwarz reduced AdS gravity on a circle. In this theory, large black holes and black strings are dual to lumps of deconfined plasma of the associated CFT. We analyze the effects that a magnetic field introduces in the Rayleigh-Plateau instability of a plasma tube, which is holographically dual to the Gregory-Laflamme instability of a magnetically charged black string.
AdS Branes from Partial Breaking of Superconformal Symmetries
Ivanov, E.A.
2005-10-01
It is shown how the static-gauge world-volume superfield actions of diverse superbranes on the AdS{sub d+1} superbackgrounds can be systematically derived from nonlinear realizations of the appropriate AdS supersymmetries. The latter are treated as superconformal symmetries of flat Minkowski superspaces of the bosonic dimension d. Examples include the N = 1 AdS{sub 4} supermembrane, which is associated with the 1/2 partial breaking of the OSp(1|4) supersymmetry down to the N = 1, d = 3 Poincare supersymmetry, and the T-duality related L3-brane on AdS{sub 5} and scalar 3-brane on AdS{sub 5} x S{sup 1}, which are associated with two different patterns of 1/2 breaking of the SU(2, 2|1) supersymmetry. Another (closely related) topic is the AdS/CFT equivalence transformation. It maps the world-volume actions of the codimension-one AdS{sub d+1} (super)branes onto the actions of the appropriate Minkowski (super)conformal field theories in the dimension d.
Worldsheet dilatation operator for the AdS superstring
NASA Astrophysics Data System (ADS)
Ramírez, Israel; Vallilo, Brenno Carlini
2016-05-01
In this work we propose a systematic way to compute the logarithmic divergences of composite operators in the pure spinor description of the AdS 5 × S 5 superstring. The computations of these divergences can be summarized in terms of a dilatation operator acting on the local operators. We check our results with some important composite operators of the formalism.
Gerrits, Thomas; Glancy, Scott; Clement, Tracy S.; Calkins, Brice; Lita, Adriana E.; Nam, Sae Woo; Mirin, Richard P.; Knill, Emanuel; Miller, Aaron J.; Migdall, Alan L.
2010-09-15
We have created heralded coherent-state superpositions (CSSs) by subtracting up to three photons from a pulse of squeezed vacuum light. To produce such CSSs at a sufficient rate, we used our high-efficiency photon-number-resolving transition edge sensor to detect the subtracted photons. This experiment is enabled by and utilizes the full photon-number-resolving capabilities of this detector. The CSS produced by three-photon subtraction had a mean-photon number of 2.75{sub -0.24}{sup +0.06} and a fidelity of 0.59{sub -0.14}{sup +0.04} with an ideal CSS. This confirms that subtracting more photons results in higher-amplitude CSSs.
Entanglement temperature and perturbed AdS3 geometry
NASA Astrophysics Data System (ADS)
Levine, G. C.; Caravan, B.
2016-06-01
Generalizing the first law of thermodynamics, the increase in entropy density δ S (x ) of a conformal field theory (CFT) is proportional to the increase in energy density, δ E (x ) , of a subsystem divided by a spatially dependent entanglement temperature, TE(x ) , a fixed parameter determined by the geometry of the subsystem, crossing over to thermodynamic temperature at high temperatures. In this paper we derive a generalization of the thermodynamic Clausius relation, showing that deformations of the CFT by marginal operators are associated with spatial temperature variations, δ TE(x ) , and spatial energy correlations play the role of specific heat. Using AdS/CFT duality we develop a relationship between a perturbation in the local entanglement temperature of the CFT and the perturbation of the bulk AdS metric. In two dimensions, we demonstrate a method through which direct diagonalizations of the boundary quantum theory may be used to construct geometric perturbations of AdS3 .
Vargas-Sanchez, Karina; Vekris, Antonios; Petry, Klaus G.
2016-01-01
To streamline in vivo biomarker discovery, we developed a suppression subtractive DNA hybridization technique adapted for phage-displayed combinatorial libraries of 12 amino acid peptides (PhiSSH). Physical DNA subtraction is performed in a one-tube-all-reactions format by sequential addition of reagents, producing the enrichment of specific clones of one repertoire. High-complexity phage repertoires produced by in vivo selections in the multiple sclerosis rat model (experimental autoimmune encephalomyelitis, EAE) and matched healthy control rats were used to evaluate the technique. The healthy repertoire served as a physical DNA subtractor from the EAE repertoire to produce the subtraction repertoire. Full next-generation sequencing (NGS) of the three repertoires was performed to evaluate the efficiency of the subtraction technique. More than 96% of the clones common to the EAE and healthy repertoires were absent from the subtraction repertoire, increasing the probability of randomly selecting various specific peptides for EAE pathology to about 70%. Histopathology experiments were performed to confirm the quality of the subtraction repertoire clones, producing distinct labeling of the blood–brain barrier (BBB) affected by inflammation among healthy nervous tissue or the preferential binding to IL1-challenged vs. resting human BBB model. Combining PhiSSH with NGS will be useful for controlled in vivo screening of small peptide combinatorial libraries to discover biomarkers of specific molecular alterations interspersed within healthy tissues. PMID:26917946
ERIC Educational Resources Information Center
Young, David G.
1983-01-01
Ad-hoc committees may be symbolic, informational, or action committees. A literature survey indicates such committees' structural components include a suprasystem and three subsystems involving linkages, production, and implementation. Other variables include size, personal factors, and timing. All the factors carry implications about ad-hoc…
Lorentzian AdS geometries, wormholes, and holography
Arias, Raul E.; Silva, Guillermo A.; Botta Cantcheff, Marcelo
2011-03-15
We investigate the structure of two-point functions for the quantum field theory dual to an asymptotically Lorentzian Anti de Sitter (AdS) wormhole. The bulk geometry is a solution of five-dimensional second-order Einstein-Gauss-Bonnet gravity and causally connects two asymptotically AdS spacetimes. We revisit the Gubser-Klebanov-Polyakov-Witten prescription for computing two-point correlation functions for dual quantum field theories operators O in Lorentzian signature and we propose to express the bulk fields in terms of the independent boundary values {phi}{sub 0}{sup {+-}} at each of the two asymptotic AdS regions; along the way we exhibit how the ambiguity of normalizable modes in the bulk, related to initial and final states, show up in the computations. The independent boundary values are interpreted as sources for dual operators O{sup {+-}} and we argue that, apart from the possibility of entanglement, there exists a coupling between the degrees of freedom living at each boundary. The AdS{sub 1+1} geometry is also discussed in view of its similar boundary structure. Based on the analysis, we propose a very simple geometric criterion to distinguish coupling from entanglement effects among two sets of degrees of freedom associated with each of the disconnected parts of the boundary.
One-loop diagrams in AdS space
Hung Lingyan; Shang Yanwen
2011-01-15
We study the complex scalar loop corrections to the boundary-boundary gauge two-point function in pure AdS space in Poincare coordinates, in the presence of boundary quadratic perturbations to the scalar. These perturbations correspond to double-trace perturbations in the dual CFT and modify the boundary conditions of the bulk scalars in AdS. We find that, in addition to the usual UV divergences, the one-loop calculation suffers from a divergence originating in the limit as the loop vertices approach the AdS horizon. We show that this type of divergence is independent of the boundary coupling; making use of this we extract the finite relative variation of the imaginary part of the loop via Cutkosky rules as the boundary perturbation varies. Applying our methods to compute the effects of a time-dependent impurity to the conductivities using the replica trick in AdS/CFT, we find that generally an IR-relevant disorder reduces the conductivity and that in the extreme low frequency limit the correction due to the impurities overwhelms the planar CFT result even though it is supposedly 1/N{sup 2} suppressed. We also comment on the more physical scenario of a time-independent impurity.
Kolmogorov-Zakharov spectrum in AdS gravitational collapse.
de Oliveira, H P; Pando Zayas, Leopoldo A; Rodrigues, E L
2013-08-01
We study black hole formation during the gravitational collapse of a massless scalar field in asymptotically D-dimensional anti-de Sitter AdS(D) spacetimes for D = 4, 5. We conclude that spherically symmetric gravitational collapse in asymptotically AdS spaces is turbulent and characterized by a Kolmogorov-Zakharov spectrum. Namely, we find that after an initial period of weakly nonlinear evolution, there is a regime where the power spectrum of the Ricci scalar evolves as ω(-s) with the frequency, ω, and s ≈ 1.7 ± 0.1.
Rubello, D; Saladini, G; Casara, D; Borsato, N; Toniato, A; Piotto, A; Bernante, P; Pelizzo, M R
2000-07-01
We set up a modified technetium-99m (Tc-99m) pertechnetate/Tc-99m MIBI (Tc-MIBI) subtraction scintigraphy for parathyroid imaging by introducing the use of potassium perchlorate (KCLO4). Initially, the effect of KCLO4 on technetium thyroid wash-out was evaluated in five healthy volunteers: 40-minute dynamic studies of the thyroid were obtained 20 minutes after the injection of technetium 150 MBq (4 mCi), both in baseline conditions and after the oral administration of 400 mg KCLO4. After an average latency time of 10.5 minutes, KCLO4 administration resulted in fast and relevant technetium thyroid wash-out with a mean half-time of 16.2 minutes (the half-time was 142.8 minutes in baseline conditions), and a 40-minute reduction of thyroid activity of 78% (it was 14% in baseline conditions). Based on these findings, a new Tc-MIBI subtraction procedure was established as follows: 1) 150 MBq technetium (4 mCi) injection; 2) 400 mg KCLO4 administered orally; 3) patient neck immobilization; 4) acquisition of a 5-minute technetium thyroid scan; 5) 500 MBq MIBI (13.5 mCi) injection; 6) acquisition of a sequence of seven MIBI images, each lasting 5 minutes; and 7) processing (image realignment when necessary, background subtraction, normalization of MIBI images to the maximum pixel count of the technetium image, and subtraction of the technetium image from the MIBI images). In addition, high-resolution neck ultrasound (US) was performed in all cases on the same day as the scintigraphic evaluation. Eighteen consecutive patients with primary hyperparathyroidism were enrolled in the study. Tc-MIBI scintigraphy revealed a single adenoma in all cases and US showed this finding in 15 of 18 cases (83.3%). Furthermore, in three patients, a thyroid nodule associated with hyperparathyroidism was detected by technetium thyroid scans and neck US. In all patients, the parathyroid adenoma was easily identified on both the 20- to 40-minute MIBI and subtracted (MIBI-Tc) images. Regarding the
NASA Technical Reports Server (NTRS)
Shyu, H. C.; Reed, I. S.; Truong, T. K.; Hsu, I. S.; Chang, J. J.
1987-01-01
A quadratic-polynomial Fermat residue number system (QFNS) has been used to compute complex integer multiplications. The advantage of such a QFNS is that a complex integer multiplication requires only two integer multiplications. In this article, a new type Fermat number multiplier is developed which eliminates the initialization condition of the previous method. It is shown that the new complex multiplier can be implemented on a single VLSI chip. Such a chip is designed and fabricated in CMOS-Pw technology.
Semiclassical Virasoro blocks from AdS3 gravity
NASA Astrophysics Data System (ADS)
Hijano, Eliot; Kraus, Per; Perlmutter, Eric; Snively, River
2015-12-01
We present a unified framework for the holographic computation of Virasoro conformal blocks at large central charge. In particular, we provide bulk constructions that correctly reproduce all semiclassical Virasoro blocks that are known explicitly from conformal field theory computations. The results revolve around the use of geodesic Witten diagrams, recently introduced in [1], evaluated in locally AdS3 geometries generated by backreaction of heavy operators. We also provide an alternative computation of the heavy-light semiclassical block — in which two external operators become parametrically heavy — as a certain scattering process involving higher spin gauge fields in AdS3; this approach highlights the chiral nature of Virasoro blocks. These techniques may be systematically extended to compute corrections to these blocks and to interpolate amongst the different semiclassical regimes.
AdS6 solutions of type II supergravity
NASA Astrophysics Data System (ADS)
Apruzzi, Fabio; Fazzi, Marco; Passias, Achilleas; Rosa, Dario; Tomasiello, Alessandro
2014-11-01
Very few AdS6 × M 4 supersymmetric solutions are known: one in massive IIA, and two IIB solutions dual to it. The IIA solution is known to be unique; in this paper, we use the pure spinor approach to give a classification for IIB supergravity. We reduce the problem to two PDEs on a two-dimensional space Σ. M 4 is then a fibration of S 2 over Σ; the metric and fluxes are completely determined in terms of the solution to the PDEs. The results seem likely to accommodate near-horizon limits of ( p, q)-fivebrane webs studied in the literature as a source of CFT5's. We also show that there are no AdS6 solutions in eleven-dimensional supergravity.
NASA Astrophysics Data System (ADS)
Fitzpatrick, J. Michael; Pickens, David R.; Mandava, Venkateswara R.; Grefenstette, John J.
1988-06-01
In the diagnosis of arteriosclerosis, radio-opaque dye is injected into the interior of the arteries to make them visible. Because of its increased contrast sensitivity, digital subtraction angiography has the potential for providing diagnostic images of arteries with reduced dye volumes. In the conventional technique, a mask image, acquired before the introduction of the dye, is subtracted from the contrast image, acquired after the dye is introduced, to produce a difference image in which only the dye in the arteries is visible. The usefulness of this technique has been severely limited by the image degradation caused by patient motion during image acquisition. This motion produces artifacts in the difference image that obscure the arteries. One technique for dealing with this problem is to reduce the degradation by means of image registration. The registration is carried out by means of a geometrical transformation of the mask image before subtraction so that it is in registration with the contrast image. This paper describes our technique for determining an optimal transformation. We employ a one-to-one elastic mapping and the Jacobian of that mapping to produce a geometrical image transformation. We choose a parameterized class of such mappings and use a heuristic search algorithm to optimize the parameters to minimize the severity of the motion artifacts. To increase the speed of the optimization process we use a statistical image comparison technique that provides a quick approximate evaluation of each image transformation. We present the experimental results of the application of our registration system to mask-contrast pairs, for images acquired from a specially designed phantom (described in a companion paper), and for clinical images.
Dual-energy subtraction imaging utilizing indium as a contrast agent
Le Duc, G.; Zhong, Z.; Warkentien, L.; Laster, B.; Thomlinson, W.
1997-10-01
The purpose of our current work is to establish the minimum detection, of indium contrast agent using dual-energy subtraction imaging above and below indium K-edge. Experiments were performed on the X12 and X17B2 beamlines at the National Synchrotron Light Source using the same method but with two different set-ups. Experiments were first carried out on InCl{sub 3} solutions, then on V79 Chinese hamster cells and on BALB/c mice excised tumors, labeled with indium. For each experiment, several layers of Lucite were placed in front of the phantom to ensure a 43 mm thickness, dose to that of a mammography examination. Results were the same on X12 and X17B2. As expected, indium-free materials disappeared on subtracted images (water, steel reference and screw). Indium samples were easily distinguishable for the following concentrations: 10-5-2-1 mg/cm{sup 2}. Smaller concentrations were not clearly distinguishable and we were unable to see cell samples and tumors. To conclude, the lowest concentration we can image is around 1 mg/cm{sup 2}. These results agree with theoretical results. Such results also suggest that indium concentration in both cells and tumors is lower than 0.5 mg/cm{sup 2}. Since the current detection is dose to optimum, we conclude that dual energy subtraction imaging using indium to label tumors cells and tumors is not possible unless the indium uptake is increased by more than an order of magnitude.
Olarte, Alexandra; Mantri, Nitin; Nugent, Gregory; Pang, Edwin C K
2013-01-01
Echinacea, native to the Canadian prairies and the prairie states of the United States, has a long tradition as a folk medicine for the Native Americans. Currently, Echinacea are among the top 10 selling herbal medicines in the U.S. and Europe, due to increasing popularity for the treatment of common cold and ability to stimulate the immune system. However, the genetic relationship within the species of this genus is unclear, making the authentication of the species used for the medicinal industry more difficult. We report the construction of a novel Subtracted Diversity Array (SDA) for Echinacea species and demonstrate the potential of this array for isolating highly polymorphic sequences. In order to selectively isolate Echinacea-specific sequences, a Suppression Subtractive Hybridization (SSH) was performed between a pool of twenty-four Echinacea genotypes and a pool of other angiosperms and non-angiosperms. A total of 283 subtracted genomic DNA (gDNA) fragments were amplified and arrayed. Twenty-seven Echinacea genotypes including four that were not used in the array construction could be successfully discriminated. Interestingly, unknown samples of E. paradoxa and E. purpurea could be unambiguously identified from the cluster analysis. Furthermore, this Echinacea-specific SDA was also able to isolate highly polymorphic retrotransposon sequences. Five out of the eleven most discriminatory features matched to known retrotransposons. This is the first time retrotransposon sequences have been used to fingerprint Echinacea, highlighting the potential of retrotransposons as based molecular markers useful for fingerprinting and studying diversity patterns in Echinacea. PMID:23940565
Rovai, D; Nissen, S E; Elion, J L; Distante, A; DeMaria, A N
1987-06-01
The purpose of this study was to evaluate whether the digital subtraction technique, applied to contrast echocardiography of the left ventricle (LV), might improve endocardial edge identification by two-dimensional echocardiography. Injections of the polysaccharide agent SHU-454 were made into the LV of five closed-chest dogs. Data were obtained at different levels of ejection fraction (EF) induced by pharmacologic or mechanical interventions and were documented by left ventriculography (VGRAM) in the right anterior oblique projection. Contrast echocardiography was recorded in the apical four-chamber view. The echocardiographic images were digitized off-line into a 256 X 256 pixel matrix with 256 gray levels/pixel. Two end-diastolic frames prior to contrast appearance were averaged to obtain a mask that was subtracted from end-diastolic contrast frames corresponding to the two beats of peak intensity. The same procedure was repeated for the systolic frames. LV edges from echocardiographic images prior to contrast appearance, from digitally subtracted echo-contrast images, and from VGRAM were traced on two occasions by two different observers. LV volumes were calculated by single-plane Simpson's rule and EF was derived by the classical equation. The intra- and interobserver reproducibility in the measurement of EF was excellent for VGRAM (r = 0.95 and 0.94, respectively), it was good for two-dimensional echocardiography (r = 0.87 and 0.73), and was fair for contrast-echo (r = 0.79 and 0.68).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3296718
Conserved higher-spin charges in AdS4
NASA Astrophysics Data System (ADS)
Gelfond, O. A.; Vasiliev, M. A.
2016-03-01
Gauge invariant conserved conformal currents built from massless fields of all spins in 4d Minkowski space-time and AdS4 are described in the unfolded dynamics approach. The current cohomology associated with non-zero conserved charges is found. The resulting list of charges is shown to match the space of parameters of the conformal higher-spin symmetry algebra in four dimensions.
Kreel, L.; Thornton, A.; Pardy, B. J.
1986-01-01
A case is presented of a glomangioma with typical history and clinical findings, proven by operation and histology. Unique radiographic features are demonstrated including visualization of the tumour on a soft tissue radiograph and associated hyperaemic bone changes, continuous wave Doppler results indicating hyperaemia and an arterio-venous malformation, and the clear demonstration of the tumour in both frontal and lateral views was possible by intra-arterial digital subtraction angiography (DSA) under local anaesthesia. Fibrous dysplasia of a femur was an incidental finding. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 PMID:3018711
Additive-Subtractive Two-Wavelength ESPI Contouring by Using a Synthetic Wavelength Phase Shift.
Hack, E; Frei, B; Kästle, R; Sennhauser, U
1998-05-01
The addition correlation of two speckle fields by simultaneousillumination at different wavelengths is used for object contouring ina Twyman-Green-type interferometer. Fringe visibility is enhancedwhen the stochastic speckle background intensity obtained from areference plane modulation is subtracted. We calculate the contourphase map by using a phase-shift algorithm in the syntheticwavelength. A comparison with a sequential illumination, phasedifference method based on a laser wavelength phase shift isgiven. The test setup does not need to be stable on aninterferometric scale, and therefore a method is provided that lendsitself to applications in noisy environments.
EKG-gated digital subtraction angiography in the detection of pulmonary emboli. [Dogs
Hirji, M.; Gamsu, G.; Webb, W.R.; Brito, A.C.; Kuriyama, K.; Stern, R.G.; Cox, L.
1984-07-01
Detection of pulmonary emboli was investigated using electrocardiographically gated (EKG-gated) intravenous digital subtraction angiography (DSA) in 6 anesthetized and paralyzed dogs. Six autologous blood clots were introducted into the internal jugular vein of each dog and both conventional pulmonary angiography and EKG- gated DSA performed in frontal and oblique projections. The authors conclude that DSA can demonstrate individual emboli with good sensitivity and excellent precision. If several emboli are present, KEG-gated DSA should prove highly accurate; however, care must be taken because overinterpretation is more likely with DSA than with conventional pulmonary angiography.
Kingsley, D P; Butler, P; Rowe, G M; Travis, R C; Wylie, I G
1989-01-01
A four year study has been undertaken into the effects on the workload and cost implications of the introduction of digital subtraction angiography (DSA) in a large United Kingdom teaching hospital. The increase in workload has been entirely due to the ability to perform intravenous angiography. DSA is cheaper than conventional angiography if more than 210 cases are undertaken each year. This difference is accounted for by the reduced use of X-ray film. However, intravenous angiography is more expensive because of the use of large volumes of nonionic medium. PMID:2674769
Gilbert, Kenneth E
2015-01-01
The original formulation of the Green's function parabolic equation (GFPE) can have numerical accuracy problems for large normalized surface impedances. To solve the accuracy problem, an improved form of the GFPE has been developed. The improved GFPE formulation is similar to the original formulation, but it has the surface-wave pole "subtracted." The improved GFPE is shown to be accurate for surface impedances varying over 2 orders of magnitude, with the largest having a magnitude exceeding 1000. Also, the improved formulation is slightly faster than the original formulation because the surface-wave component does not have to be computed separately.
NASA Astrophysics Data System (ADS)
Xu, Jing; Liu, Xiaofei; Wang, Yutian
2016-08-01
Parallel factor analysis is a widely used method to extract qualitative and quantitative information of the analyte of interest from fluorescence emission-excitation matrix containing unknown components. Big amplitude of scattering will influence the results of parallel factor analysis. Many methods of eliminating scattering have been proposed. Each of these methods has its advantages and disadvantages. The combination of symmetrical subtraction and interpolated values has been discussed. The combination refers to both the combination of results and the combination of methods. Nine methods were used for comparison. The results show the combination of results can make a better concentration prediction for all the components.
Digital subtraction angiography of the pulmonary arteries for the diagnosis of pulmonary embolism
Ludwig, J.W.; Verhoeven, L.A.J.; Kersbergen, J.J.; Overtoom, T.T.C.
1983-06-01
A comparative study of radionuclide scanning (perfusion studies in all 18 patients and ventilation studies in 9) and digital subtraction angiography (DSA) was performed in 18 patients with suspected pulmonary thromboembolism. In 17 patients good visualization of the arteries was obtained with DSA; 10 of these patients had no pre-existing lung disease, and 7 had chronic obstructive pulmonary disease (COPD). The information provided by DSA in this small group was equal to or better than that of scintigraphy, especially in patients with COPD, and the reliability of DSA was superior to that of the radionuclide scintigraphy. Methods for preventing motion artifacts with DSA are also described.
Wei, Ning; Xu, Xiang-Dong; Xu, Hao; Zu, Mao-Heng
2014-01-01
Leiomyosarcoma of vascular origin is a rare disease and most cases arise in the inferior vena cava. Inferior vena cava leiomyosarcoma (IVCLMS) usually presents in females in their sixth decade of life. The clinical symptoms are often non-specific and the diagnosis is often delayed. Current imaging techniques can accurately differentiate inferior vena cava neoplasms from other non-neoplastic lesions. However, definitive diagnosis of IVCLMS needs histologic evidence. We report a case of IVCLMS in a 61-year old Chinese woman. This is the first IVCLMS case confirmed by catheter suction biopsy during digital subtraction angiography. PMID:25232438
Optical half-adder and half-subtracter employing the Pockels effect.
Jiang, Haowei; Chen, Yuping; Li, Guangzhen; Zhu, Chuanyi; Chen, Xianfeng
2015-04-20
The Pockels effect in periodically poled lithium niobate made it possible to switch optical signals between two orthogonal optical linear polarizations of the vertical and horizontal polarization states. Based on this effect, we demonstrated polarization-based binary optical logic gates: AND, and OR gates. By combining these basic gates with other polarization-based optical logic gates such as XOR gate accomplished in our previous researches, half-adder and half-subtracter of digital signals with a high extinction ratio of about 10dB have been demonstrated in our experiment, which made it possible to run more complex logical calculus. PMID:25969018
Sky subtraction at the Poisson limit with fibre-optic multiobject spectroscopy
NASA Astrophysics Data System (ADS)
Sharp, R.; Parkinson, H.
2010-11-01
We report on the limitations of sky-subtraction accuracy for long-duration fibre-optic multiobject spectroscopy of faint astronomical sources during long-duration exposures. We show that while standard sky subtraction techniques yield accuracies consistent with the Poisson noise limit for exposures of 1h duration, there are large-scale systematic defects that inhibit the sensitivity gains expected on the summation of longer duration exposures. For the AAOmega system at the Anglo-Australian Telescope, we identify a limiting systematic sky-subtraction accuracy, which is reached after integration times of 4-10h. We show that these systematic defects can be avoided through the use of the fibre nod-and-shuffle (N+S) observing mode, but with a potential cost in observing efficiency. Finally, we demonstrate that these disadvantages can be overcome through the application of a Principal Components Analysis (PCA) sky-subtraction routine. Such an approach minimize systematic residuals across long-duration exposures, allowing deep integrations. We apply the PCA approach to over 200h of on-sky observations and conclude that for the AAOmega system, the residual error in long-duration observations falls at a rate proportional to τ-0.32 in contrast to the τ-0.5 rate expected from theoretical considerations. With this modest rate of decline, the PCA approach represents a more efficient mode of observation than the N+S technique for observations in the sky limited regime with durations of 10-100h (even before accounting for the additional signal-to-noise ratio and targeting efficiency losses often associated with the N+S technique). This conclusion has important implications for the observing strategies of the next generation of fibre-optics redshift surveys with existing facilities as well as design implications for fibre-optic systems destined for new facilities. It argues against the use of the inherently inefficient N+S technique for faint object fibre-optic survey
Wang, Mingjie; Doak, Thomas G; Ye, Yuzhen
2015-11-02
Comparative metagenomics remains challenging due to the size and complexity of metagenomic datasets. Here we introduce subtractive assembly, a de novo assembly approach for comparative metagenomics that directly assembles only the differential reads that distinguish between two groups of metagenomes. Using simulated datasets, we show it improves both the efficiency of the assembly and the assembly quality of the differential genomes and genes. Further, its application to type 2 diabetes (T2D) metagenomic datasets reveals clear signatures of the T2D gut microbiome, revealing new phylogenetic and functional features of the gut microbial communities associated with T2D.
Anatomic and functional imaging of congenital heart disease with digital subtraction angiography
Buonocore, E.; Pavlicek, W.; Modic, M.T.; Meaney, T.F.; O'Donovan, P.B.; Grossman, L.B.; Moodie, D.S.; Yiannikas, J.
1983-06-01
Digital subtraction angiography (DSA) of the heart was performed in 54 patients for the evaluation of congenital heart diagnostic images and accurate physiologic shunt data that compared favorably with catheter angiography and nuclear medicine studies. Retrospective analysis of this series of patients indicated that DSA studies contributed sufficient informantion to shorten significantly or modify cardiac catheterization in 85% (79/93) of the defects that were identified. Interatrial septal defects were particularly well diagnosed, with identification occurring in 10 of 10 cases, wheseas intraventricular septal defects were identified in only 6 of 9 patients. Evaluation of postsurgical patients was accurate in 19 of 20 cases.
Xu, Jing; Liu, Xiaofei; Wang, Yutian
2016-08-01
Parallel factor analysis is a widely used method to extract qualitative and quantitative information of the analyte of interest from fluorescence emission-excitation matrix containing unknown components. Big amplitude of scattering will influence the results of parallel factor analysis. Many methods of eliminating scattering have been proposed. Each of these methods has its advantages and disadvantages. The combination of symmetrical subtraction and interpolated values has been discussed. The combination refers to both the combination of results and the combination of methods. Nine methods were used for comparison. The results show the combination of results can make a better concentration prediction for all the components. PMID:27100020
On information loss in AdS3/CFT2
Fitzpatrick, A. Liam; Kaplan, Jared; Li, Daliang; Wang, Junpu
2016-05-18
We discuss information loss from black hole physics in AdS3, focusing on two sharp signatures infecting CFT2 correlators at large central charge c: ‘forbidden singularities’ arising from Euclidean-time periodicity due to the effective Hawking temperature, and late-time exponential decay in the Lorentzian region. We study an infinite class of examples where forbidden singularities can be resolved by non-perturbative effects at finite c, and we show that the resolution has certain universal features that also apply in the general case. Analytically continuing to the Lorentzian regime, we find that the non-perturbative effects that resolve forbidden singularities qualitatively change the behavior ofmore » correlators at times t ~SBH, the black hole entropy. This may resolve the exponential decay of correlators at late times in black hole backgrounds. By Borel resumming the 1/c expansion of exact examples, we explicitly identify ‘information-restoring’ effects from heavy states that should correspond to classical solutions in AdS3. Lastly, our results suggest a line of inquiry towards a more precise formulation of the gravitational path integral in AdS3.« less
Narnoliya, Lokesh K; Rajakani, Raja; Sangwan, Neelam S; Gupta, Vikrant; Sangwan, Rajender S
2014-05-01
Azadirachta indica (neem) is a medicinally important plant that is valued for its bioactive secondary metabolites. Higher levels of the bioactive phytochemicals are accumulated in fruits than in other tissues. In the present study, a total of 387 and 512 ESTs, respectively, from endocarp and mesocarp of neem fruits were isolated and analyzed. Out of them 318 ESTs (82.17%) clones from endocarp and 418 ESTs (81.64%) from mesocarp encoded putative proteins that could be classified into three major gene ontology categories: biological process, molecular function and cellular component. From the analyses of contigs, 73 unigenes from the forward subtracted library and 35 unigenes from the reverse subtracted library were obtained. The ESTs from mesocarp encoded cytochrome P450 enzymes, which indicated hydroxylation to be a major metabolic event and that biogeneration of hydroxylated neem fruit phytochemicals was differentially regulated with developmental stage-specificity of synthesis. Through this study, we present the first report of any gene expression data in neem tissues. Neem hydroxy-methyl glutaryl-coenzyme A reductase (NHMGR) gene was used as expressing control vis-a-vis subtracted tissues. NHMGR was present in fruit, endocarp and mesocarp tissues, but absent in subtractive libraries, revealing that it was successfully eliminated during subtraction. Eight genes of interest from subtracted libraries were profiled for their expression in fruit, mesocarp and endocarp. Expression profiles validated the quality of the libraries and functional diversity of the tissues. The subtractive cDNA library and EST database described in this study represent a valuable transcript sequence resource for future research aimed at improving the economically important medicinal plant.
Valizadeh, Solmaz; Ehsani, Sara; Esmaeili, Farzad; Tavakoli, Mohammad Amin
2008-01-01
Background and aims Radiography is used to diagnose the demineralization process and carious lesions; however, conventional radiography and direct digital images do not show these lesions when the amount of demineralization is less than 40%. Digital subtraction radiography has recently been used to improve the diagnostic quality of these le-sions. The purpose of this study was to compare the caries depth estimated by digital subtraction radiog-raphy in combination with barium sulfate in diag-nosing proximal dental caries with histopathologic evaluation. Materials and methods In this study 30 molars and premolars (24 demineralized lesions with cavity, 8 without cavity) were studied. Direct digital images were taken (kVp: 68, mA: 8; t: 0.12 for premolars and t: 0.16 for molars) whereas the position of X-ray tube and CCD receptor and teeth was fixed. To prepare the second images 135 gr/L barium sulfate was used. The images obtained with the same exposure and geometry and then subtracted. The depth of the lesions in direct digital and subtracted images were assessed and compared with the depth measured in histopathologic assessments. Results The mean depths (± SD) of the lesions were 1.80 ± 0.77 mm in direct digital radiography, 2.32 ± 0.76 mm in subtracted images after barium sulfate treatment, and 2.51 ± 0.43 mm in histopathologic sections. The statistical difference between direct digital radiography and the other methods was significant (P < 0.05). However, the differences were not statistically significant between subtracted images and histopathologic sections. The average intra-class correlation coefficient was 0.7241 (CI: 95%). Conclusion The present study has demonstrated that digital subtraction radiography images have the potential to measure the depth of proximal caries with no significant difference with histopathologic evaluation. PMID:23277849
Partial Collapse of Plinian Volcanic Jets and the Production of Multiply Layered Ash Clouds
NASA Astrophysics Data System (ADS)
Gilchrist, J. T.; Jellinek, M.
2014-12-01
Powerful explosive volcanic eruptions inject ash high into the atmosphere, which spreads as an intrusion to form characteristic umbrella-shaped clouds. An enigmatic feature of a number of recent eruption clouds (e.g. Popocatepetl, 2012; Soufriere Hills, 2010; Mt. St. Helens, 1980 and Puyehue, 2011) is that they are constructed of multiple layers (Figure 1, left). How such layering emerges within an advancing gravity current of initially well-mixed ash is unclear. Potential major controls include the strength and structure of the atmospheric density stratification, the particle size distribution within the ash cloud and the entrainment of ambient atmosphere into the rising plume. Accordingly, we conduct analog experiments in which saltwater jets with mono- and bi-disperse suspensions of fine and coarse silica particles are injected into a saltwater tank with a linear density stratification. Whereas classical umbrella clouds are produced for strong jets (low source Richardson number, -Ri0) under all particle-loading conditions, multiply layered clouds emerge for weak jets (high -Ri0) and relatively concentrated bi-disperse and coarse mono-disperse suspensions. In particular, at high -Ri0 coarse particles inhibit entrainment and enhance the partial collapse of rising jets to form gravity currents that intermittently descend along the jet margin and spread at varying neutral buoyancy heights to form layers. For high concentrations of coarse sand gravity currents can reach the tank floor. Collapse and compaction of this material to form a deposit expels buoyant interstitial fluid that rises to form additional layers below and within the overlying multiply layered cloud. One layer and multiply layered clouds have distinct depositional patterns and present unique risks to air traffic.
Pilot Study of Cartilage Repair in the Knee Joint with Multiply Incised Chondral Allograft
Vancsodi, Jozsef; Farkas, Boglarka; Fazekas, Adam; Nagy, Szilvia Anett; Bogner, Peter; Vermes, Csaba; Than, Peter
2015-01-01
Background Focal cartilage lesions in the knee joint have limited capacity to heal. Current animal experiments show that incisions of the deep zone of a cartilage allograft allow acceptable integration for the graft. Questions/Purposes We performed this clinical study to determine (1) if the multiply incised cartilage graft is surgically applicable for focal cartilage lesions, (2) whether this allograft has a potential to integrate to the repair site, and (3) if patients show clinical improvement. Patients and Methods Seven patients with 8 chondral lesions were enrolled into the study. Symptomatic lesions between 2 and 8 cm2 were accepted. Additional injuries were allowed but were addressed simultaneously. Grafts were tailored to match and the deep zone of the cartilage was multiply incised to augment the basal integration before securing in place. Rigorous postoperative physiotherapy followed. At 12 and 24 months the patients’ satisfaction were measured and serial magnetic resonance imaging (MRI) was performed in 6 patients. Results Following the implantations no adverse reaction occurred. MRI evaluation postoperatively showed the graft in place in 5 out of 6 patients. In 1 patient, MRI suggested partial delamination at 1 year and graft degeneration at 2 years. Short Form–36 health survey and the Lysholm knee score demonstrated a significant improvement in the first year; however, by 2 years there was a noticeable drop in the scores. Conclusions. Multiply incised pure chondral allograft used for cartilage repair appears to be a relatively safe method. Further studies are necessary to assess its potential in cartilage repair before its clinical use. PMID:26069710
Brodsky, Stanley J.; de Teramond, Guy F.; /Costa Rica U. /SLAC
2007-02-21
The AdS/CFT correspondence between string theory in AdS space and conformal .eld theories in physical spacetime leads to an analytic, semi-classical model for strongly-coupled QCD which has scale invariance and dimensional counting at short distances and color confinement at large distances. Although QCD is not conformally invariant, one can nevertheless use the mathematical representation of the conformal group in five-dimensional anti-de Sitter space to construct a first approximation to the theory. The AdS/CFT correspondence also provides insights into the inherently non-perturbative aspects of QCD, such as the orbital and radial spectra of hadrons and the form of hadronic wavefunctions. In particular, we show that there is an exact correspondence between the fifth-dimensional coordinate of AdS space z and a specific impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron in ordinary space-time. This connection allows one to compute the analytic form of the frame-independent light-front wavefunctions, the fundamental entities which encode hadron properties and allow the computation of decay constants, form factors, and other exclusive scattering amplitudes. New relativistic lightfront equations in ordinary space-time are found which reproduce the results obtained using the 5-dimensional theory. The effective light-front equations possess remarkable algebraic structures and integrability properties. Since they are complete and orthonormal, the AdS/CFT model wavefunctions can also be used as a basis for the diagonalization of the full light-front QCD Hamiltonian, thus systematically improving the AdS/CFT approximation.
Design and Testing of a Load Current Multiplier on Zebra Facility
Chuvatin, A. S.; Kantsyrev, V. L.; Astanovitskiy, A. L.; Presura, R.; Safronova, A. S.; Esaulov, A. A.; Cline, W.; Williamson, K. M.; Shrestha, I.; Yilmaz, M. F.; Osborne, G. C.; Weller, M.; Jarrett, T.; LeGalloudec, B.; Nalajala, V.; Rudakov, L. I.; Cuneo, M. E.; Pointon, T. D.; Mikkelson, K. A.
2009-01-21
The Load Current Multiplier concept (LCM) was validated for the first time on a high-voltage nanosecond pulse-power generator. The designed new device allowed to increase the load current from the nominal 0.8-0.9 MA up to 1.6 MA in static loads with constant inductance and up to 1.4 MA in a planar wire-array plasma loads. These results were achieved without modifying the generator energetic or architecture. LCM allowed both the load magnetic energy increase and the increase of soft X-ray radiation from z-pinch plasmas.
Design of Wallace tree multiplier and other components of a quantum ALU using reversible TSG gate
NASA Astrophysics Data System (ADS)
Thapliyal, Himanshu; Srinivas, M. B.
2006-05-01
This paper presents the design of a novel modified Wallace tree multiplier, using the reversible TSG gate proposed by the authors earlier. The novelty of the TSG gate is that it can also work singly as a reversible full adder. The TSG gate is also used in this paper to design various other reversible arithmetic and logical components that can be assembled to realize a primitive reversible/quantum ALU. It is also shown that these components are optimal, in terms of number of reversible gates and garbage outputs, compared to other designs existing in literature.
Quantum efficiency of a channel electron multiplier in the far ultraviolet
NASA Technical Reports Server (NTRS)
Paresce, F.
1975-01-01
Variation of the quantum efficiency of a channel electron multiplier (CEM) in the wavelength range from 1200 to 2536 A is studied. Emphasis is on measurement of CEM sensitivity longward of 1500 A. Results indicate an overall rapid decrease in quantum efficiency with increasing wavelength, with little evidence for a possible change in slope in the range from 2000 to 2500 A. The lowest efficiency measured is 4.5 + or -2.5 times 10 to the minus ninth count/photon at 2536 A. These efficiencies should ensure that unwanted radiation longward of 1500 A can be effectively removed from the bandpass of the instrument.
NASA Astrophysics Data System (ADS)
Zettergren, Henning; Holm, Anne I. S.; Johansson, Henrik; Cederquist, Henrik
2012-11-01
We have studied multiply ionization for a range of Polycyclic Aromatic Hydrocarbons (PAHs) and their charge dependent stabilities with respect to H-, H+-, C2H2- and C2H2+-emissions by means of Density Functional Theory. The adiabatic dissociation energies reveal information about the competition between these channels as functions of PAH charge state and provide predictions of the thermodynamical stability limits, while the sequences of ionization energies may e.g. be used to extract absolute ionization cross sections of astrophysical relevance.
A Sealed, UHV Compatible, Soft X-ray Detector Utilizing Gas Electron Multipliers
Schaknowski, N.A.; Smith, G.
2009-10-25
An advanced soft X-ray detector has been designed and fabricated for use in synchrotron experiments that utilize X-ray absorption spectroscopy in the study a wide range of materials properties. Fluorescence X-rays, in particular C{sub K} at 277eV, are converted in a low pressure gas medium, and charge multiplication occurs in two gas electron multipliers, fabricated in-house from glass reinforced laminate, to enable single photon counting. The detector satisfies a number of demanding characteristics often required in synchrotron environments, such as UHV compatibility compactness, long-term stability, and energy resolving capability.
Highly linear high-density vector quantiser and vector-matrix multiplier
NASA Astrophysics Data System (ADS)
Pedroni, V. A.
1994-06-01
Simplicity is a key factor in the development of high-density systems. The authors discuss a balanced, four-quadrant, fully-analogue vector-matrix multiplier (VMM) and a vector quantiser (VQ) which require very small silicon area for their implementations, while presenting high linearity, a totally flexible input dynamic range, a symmetric power consumption behaviour, and are inherently suitable for parallel operation. The circuits require only four transistors per synapse in the VMM and two in the VQ, plus two (small) refresh transistors.