WorldWideScience

Sample records for analog computers

  1. Analog computing

    CERN Document Server

    Ulmann, Bernd

    2013-01-01

    This book is a comprehensive introduction to analog computing. As most textbooks about this powerful computing paradigm date back to the 1960s and 1970s, it fills a void and forges a bridge from the early days of analog computing to future applications. The idea of analog computing is not new. In fact, this computing paradigm is nearly forgotten, although it offers a path to both high-speed and low-power computing, which are in even more demand now than they were back in the heyday of electronic analog computers.

  2. Analog and hybrid computing

    CERN Document Server

    Hyndman, D E

    2013-01-01

    Analog and Hybrid Computing focuses on the operations of analog and hybrid computers. The book first outlines the history of computing devices that influenced the creation of analog and digital computers. The types of problems to be solved on computers, computing systems, and digital computers are discussed. The text looks at the theory and operation of electronic analog computers, including linear and non-linear computing units and use of analog computers as operational amplifiers. The monograph examines the preparation of problems to be deciphered on computers. Flow diagrams, methods of ampl

  3. Quantum Analog Computing

    Science.gov (United States)

    Zak, M.

    1998-01-01

    Quantum analog computing is based upon similarity between mathematical formalism of quantum mechanics and phenomena to be computed. It exploits a dynamical convergence of several competing phenomena to an attractor which can represent an externum of a function, an image, a solution to a system of ODE, or a stochastic process.

  4. Analog computing by Brewster effect.

    Science.gov (United States)

    Youssefi, Amir; Zangeneh-Nejad, Farzad; Abdollahramezani, Sajjad; Khavasi, Amin

    2016-08-01

    Optical computing has emerged as a promising candidate for real-time and parallel continuous data processing. Motivated by recent progresses in metamaterial-based analog computing [Science343, 160 (2014)SCIEAS0036-807510.1126/science.1242818], we theoretically investigate the realization of two-dimensional complex mathematical operations using rotated configurations, recently reported in [Opt. Lett.39, 1278 (2014)OPLEDP0146-959210.1364/OL.39.001278]. Breaking the reflection symmetry, such configurations could realize both even and odd Green's functions associated with spatial operators. Based on such an appealing theory and by using the Brewster effect, we demonstrate realization of a first-order differentiator. Such an efficient wave-based computation method not only circumvents the major potential drawbacks of metamaterials, but also offers the most compact possible device compared to conventional bulky lens-based optical signal and data processors.

  5. An Analog Computer for Electronic Engineering Education

    Science.gov (United States)

    Fitch, A. L.; Iu, H. H. C.; Lu, D. D. C.

    2011-01-01

    This paper describes a compact analog computer and proposes its use in electronic engineering teaching laboratories to develop student understanding of applications in analog electronics, electronic components, engineering mathematics, control engineering, safe laboratory and workshop practices, circuit construction, testing, and maintenance. The…

  6. Discrete analog computing with rotor-routers.

    Science.gov (United States)

    Propp, James

    2010-09-01

    Rotor-routing is a procedure for routing tokens through a network that can implement certain kinds of computation. These computations are inherently asynchronous (the order in which tokens are routed makes no difference) and distributed (information is spread throughout the system). It is also possible to efficiently check that a computation has been carried out correctly in less time than the computation itself required, provided one has a certificate that can itself be computed by the rotor-router network. Rotor-router networks can be viewed as both discrete analogs of continuous linear systems and deterministic analogs of stochastic processes.

  7. Computational approaches to analogical reasoning current trends

    CERN Document Server

    Richard, Gilles

    2014-01-01

    Analogical reasoning is known as a powerful mode for drawing plausible conclusions and solving problems. It has been the topic of a huge number of works by philosophers, anthropologists, linguists, psychologists, and computer scientists. As such, it has been early studied in artificial intelligence, with a particular renewal of interest in the last decade. The present volume provides a structured view of current research trends on computational approaches to analogical reasoning. It starts with an overview of the field, with an extensive bibliography. The 14 collected contributions cover a large scope of issues. First, the use of analogical proportions and analogies is explained and discussed in various natural language processing problems, as well as in automated deduction. Then, different formal frameworks for handling analogies are presented, dealing with case-based reasoning, heuristic-driven theory projection, commonsense reasoning about incomplete rule bases, logical proportions induced by similarity an...

  8. A computational model of analogical reasoning

    Institute of Scientific and Technical Information of China (English)

    李波; 赵沁平

    1997-01-01

    A computational model of analogical reasoning is presented, which divides analogical reasoning process into four subprocesses, i.e. reminding, elaboration, matching and transfer. For each subprocess, its role and the principles it follows are given. The model is discussed in detail, including salient feature-based reminding, relevance-directed elaboration, an improved matching model and a transfer model. And the advantages of this model are summarized based on the results of BHARS, which is an analogical reasoning system implemented by this model.

  9. Landauer Bound for Analog Computing Systems

    CERN Document Server

    Diamantini, M Cristina; Trugenberger, Carlo A

    2016-01-01

    By establishing a relation between information erasure and continuous phase transitions we generalise the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy.

  10. Landauer bound for analog computing systems

    Science.gov (United States)

    Diamantini, M. Cristina; Gammaitoni, Luca; Trugenberger, Carlo A.

    2016-07-01

    By establishing a relation between information erasure and continuous phase transitions we generalize the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence, every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy.

  11. Analog Computation by DNA Strand Displacement Circuits.

    Science.gov (United States)

    Song, Tianqi; Garg, Sudhanshu; Mokhtar, Reem; Bui, Hieu; Reif, John

    2016-08-19

    DNA circuits have been widely used to develop biological computing devices because of their high programmability and versatility. Here, we propose an architecture for the systematic construction of DNA circuits for analog computation based on DNA strand displacement. The elementary gates in our architecture include addition, subtraction, and multiplication gates. The input and output of these gates are analog, which means that they are directly represented by the concentrations of the input and output DNA strands, respectively, without requiring a threshold for converting to Boolean signals. We provide detailed domain designs and kinetic simulations of the gates to demonstrate their expected performance. On the basis of these gates, we describe how DNA circuits to compute polynomial functions of inputs can be built. Using Taylor Series and Newton Iteration methods, functions beyond the scope of polynomials can also be computed by DNA circuits built upon our architecture.

  12. Optimal neural computations require analog processors

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.

    1998-12-31

    This paper discusses some of the limitations of hardware implementations of neural networks. The authors start by presenting neural structures and their biological inspirations, while mentioning the simplifications leading to artificial neural networks. Further, the focus will be on hardware imposed constraints. They will present recent results for three different alternatives of parallel implementations of neural networks: digital circuits, threshold gate circuits, and analog circuits. The area and the delay will be related to the neurons` fan-in and to the precision of their synaptic weights. The main conclusion is that hardware-efficient solutions require analog computations, and suggests the following two alternatives: (i) cope with the limitations imposed by silicon, by speeding up the computation of the elementary silicon neurons; (2) investigate solutions which would allow the use of the third dimension (e.g. using optical interconnections).

  13. Analog models of computations \\& Effective Church Turing Thesis: Efficient simulation of Turing machines by the General Purpose Analog Computer

    CERN Document Server

    Pouly, Amaury; Graça, Daniel S

    2012-01-01

    \\emph{Are analog models of computations more powerful than classical models of computations?} From a series of recent papers, it is now clear that many realistic analog models of computations are provably equivalent to classical digital models of computations from a \\emph{computability} point of view. Take, for example, the probably most realistic model of analog computation, the General Purpose Analog Computer (GPAC) model from Claude Shannon, a model for Differential Analyzers, which are analog machines used from 1930s to early 1960s to solve various problems. It is now known that functions computable by Turing machines are provably exactly those that are computable by GPAC. This paper is about next step: understanding if this equivalence also holds at the \\emph{complexity} level. In this paper we show that the realistic models of analog computation -- namely the General Purpose Analog Computer (GPAC) -- can simulate Turing machines in a computationally efficient manner. More concretely we show that, modulo...

  14. Analog computing using reflective plasmonic metasurfaces

    CERN Document Server

    Pors, Anders; Bozhevolnyi, Sergey I

    2016-01-01

    Motivated by the recent renewed interest in compact analog computing using light and metasurfaces (Silva, A. et al., Science 2014, 343, 160-163), we suggest a practical approach to its realization that involves reflective metasurfaces consisting of arrayed gold nanobricks atop a subwavelength-thin dielectric spacer and optically-thick gold film, a configuration that supports gap-surface plasmon resonances. Using well established numerical routines, we demonstrate that these metasurfaces enable independent control of the light phase and amplitude, and design differentiator and integrator metasurfaces featuring realistic system parameters. Proof-of-principle experiments are reported along with the successful realization of a high-quality poor-man's integrator metasurface operating at the wavelength of 800 nm.

  15. Synthetic analog and digital circuits for cellular computation and memory

    OpenAIRE

    Purcell, Oliver; Lu, Timothy K.

    2014-01-01

    Biological computation is a major area of focus in synthetic biology because it has the potential to enable a wide range of applications. Synthetic biologists have applied engineering concepts to biological systems in order to construct progressively more complex gene circuits capable of processing information in living cells. Here, we review the current state of computational genetic circuits and describe artificial gene circuits that perform digital and analog computation. We then discuss r...

  16. Synthesis of computational structures for analog signal processing

    CERN Document Server

    Popa, Cosmin Radu

    2011-01-01

    Presents the most important classes of computational structures for analog signal processing, including differential or multiplier structures, squaring or square-rooting circuits, exponential or Euclidean distance structures and active resistor circuitsIntroduces the original concept of the multifunctional circuit, an active structure that is able to implement, starting from the same circuit core, a multitude of continuous mathematical functionsCovers mathematical analysis, design and implementation of a multitude of function generator structures

  17. An Analog Analogue of a Digital Quantum Computation

    CERN Document Server

    Farhi, E; Farhi, Edward; Gutmann, Sam

    1998-01-01

    We solve a problem, which while not fitting into the usual paradigm, can be viewed as a quantum computation. Suppose we are given a quantum system described by an N dimensional Hilbert space with a Hamiltonian of the form $E |w >$ is an unknown (normalized) state. We show how to discover $| w >$ by adding a Hamiltonian (independent of $| w >$) and evolving for a time proportional to $N^{1/2}/E$. We show that this time is optimally short. This process is an analog analogue to Grover's algorithm, a computation on a conventional (!) quantum computer which locates a marked item from an unsorted list of N items in a number of steps proportional to $N^{1/2}$.

  18. Accurate and Precise Computation Using Analog VLSI, with Applications to Computer Graphics and Neural Networks.

    Science.gov (United States)

    Kirk, David Blair

    This thesis develops an engineering practice and design methodology to enable us to use CMOS analog VLSI chips to perform more accurate and precise computation. These techniques form the basis of an approach that permits us to build computer graphics and neural network applications using analog VLSI. The nature of the design methodology focuses on defining goals for circuit behavior to be met as part of the design process. To increase the accuracy of analog computation, we develop techniques for creating compensated circuit building blocks, where compensation implies the cancellation of device variations, offsets, and nonlinearities. These compensated building blocks can be used as components in larger and more complex circuits, which can then also be compensated. To this end, we develop techniques for automatically determining appropriate parameters for circuits, using constrained optimization. We also fabricate circuits that implement multi-dimensional gradient estimation for a gradient descent optimization technique. The parameter-setting and optimization tools allow us to automatically choose values for compensating our circuit building blocks, based on our goals for the circuit performance. We can also use the techniques to optimize parameters for larger systems, applying the goal-based techniques hierarchically. We also describe a set of thought experiments involving circuit techniques for increasing the precision of analog computation. Our engineering design methodology is a step toward easier use of analog VLSI to solve problems in computer graphics and neural networks. We provide data measured from compensated multipliers built using these design techniques. To demonstrate the feasibility of using analog VLSI for more quantitative computation, we develop small applications using the goal-based design approach and compensated components. Finally, we conclude by discussing the expected significance of this work for the wider use of analog VLSI for

  19. Analog Optical Computing Based on Dielectric Meta-reflect-array

    CERN Document Server

    Chizari, Ata; Jamali, Mohammad Vahid; Salehi, Jawad A

    2016-01-01

    In this paper, we realize the concept of analog computing using an array of engineered gradient dielectric meta-reflect-array. The proposed configuration consists of individual subwavelength silicon nanobricks in combination with fused silica spacer and silver ground plane realizing a reflection beam with full phase coverage $2\\pi$ degrees as well as amplitude range $0$ to $1$. Spectrally overlapping electric and magnetic dipole resonances, such high-index dielectric metasurfaces can locally and independently manipulate the amplitude and phase of the incident electromagnetic wave. This practically feasible structure overcomes substantial limitations imposed by plasmonic metasurfaces such as absorption losses and low polarization conversion efficiency in the visible range. Using such CMOS-compatible and easily integrable platforms promises highly efficient ultrathin planar wave-based computing systems which circumvent the drawbacks of conventional bulky lens-based signal processors. Based on these key properti...

  20. The Effects of Analogies and Mathematics Ability on Students' Programming Learning Using Computer-Based Learning.

    Science.gov (United States)

    Lai, Shu-Ling; Repman, Judith L.

    1996-01-01

    Purposes of this study were to determine: (1) if analogies and elaboration and placement of the analogies help novices learning a computer-programming language; (2) if students' mathematics ability influences programming learning; and (3) the interaction effects between analogy and mathematics ability. Subjects were 156 college students. Results…

  1. Scalable Low-Power Deep Machine Learning with Analog Computation

    Science.gov (United States)

    2013-07-19

    learning task. We have further designed a second more complex learning chip. We have made significant innovations to the algorithm to facilitate analog ...Paper 2.00 3.00 Junjie Lu, Steven Young, Itamar Arel, Jeremy Holleman. An analog online clustering circuit in 130nm CMOS , 2013 IEEE Asian Solid-State...further designed and fabricated a second more complex learning chip. We have made significant innovations to the algorithm to facilitate analog

  2. Continuous analog of multiplicative algebraic reconstruction technique for computed tomography

    Science.gov (United States)

    Tateishi, Kiyoko; Yamaguchi, Yusaku; Abou Al-Ola, Omar M.; Kojima, Takeshi; Yoshinaga, Tetsuya

    2016-03-01

    We propose a hybrid dynamical system as a continuous analog to the block-iterative multiplicative algebraic reconstruction technique (BI-MART), which is a well-known iterative image reconstruction algorithm for computed tomography. The hybrid system is described by a switched nonlinear system with a piecewise smooth vector field or differential equation and, for consistent inverse problems, the convergence of non-negatively constrained solutions to a globally stable equilibrium is guaranteed by the Lyapunov theorem. Namely, we can prove theoretically that a weighted Kullback-Leibler divergence measure can be a common Lyapunov function for the switched system. We show that discretizing the differential equation by using the first-order approximation (Euler's method) based on the geometric multiplicative calculus leads to the same iterative formula of the BI-MART with the scaling parameter as a time-step of numerical discretization. The present paper is the first to reveal that a kind of iterative image reconstruction algorithm is constructed by the discretization of a continuous-time dynamical system for solving tomographic inverse problems. Iterative algorithms with not only the Euler method but also the Runge-Kutta methods of lower-orders applied for discretizing the continuous-time system can be used for image reconstruction. A numerical example showing the characteristics of the discretized iterative methods is presented.

  3. Structure problems in the analog computation; Problemes de structure dans le calcul analogique

    Energy Technology Data Exchange (ETDEWEB)

    Braffort, P.L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    The recent mathematical development showed the importance of elementary structures (algebraic, topological, etc.) in abeyance under the great domains of classical analysis. Such structures in analog computation are put in evidence and possible development of applied mathematics are discussed. It also studied the topological structures of the standard representation of analog schemes such as additional triangles, integrators, phase inverters and functions generators. The analog method gives only the function of the variable: time, as results of its computations. But the course of computation, for systems including reactive circuits, introduces order structures which are called 'chronological'. Finally, it showed that the approximation methods of ordinary numerical and digital computation present the same structure as these analog computation. The structure analysis permits fruitful comparisons between the several domains of applied mathematics and suggests new important domains of application for analog method. (M.P.)

  4. Analog computation through high-dimensional physical chaotic neuro-dynamics

    Science.gov (United States)

    Horio, Yoshihiko; Aihara, Kazuyuki

    2008-07-01

    Conventional von Neumann computers have difficulty in solving complex and ill-posed real-world problems. However, living organisms often face such problems in real life, and must quickly obtain suitable solutions through physical, dynamical, and collective computations involving vast assemblies of neurons. These highly parallel computations through high-dimensional dynamics (computation through dynamics) are completely different from the numerical computations on von Neumann computers (computation through algorithms). In this paper, we explore a novel computational mechanism with high-dimensional physical chaotic neuro-dynamics. We physically constructed two hardware prototypes using analog chaotic-neuron integrated circuits. These systems combine analog computations with chaotic neuro-dynamics and digital computation through algorithms. We used quadratic assignment problems (QAPs) as benchmarks. The first prototype utilizes an analog chaotic neural network with 800-dimensional dynamics. An external algorithm constructs a solution for a QAP using the internal dynamics of the network. In the second system, 300-dimensional analog chaotic neuro-dynamics drive a tabu-search algorithm. We demonstrate experimentally that both systems efficiently solve QAPs through physical chaotic dynamics. We also qualitatively analyze the underlying mechanism of the highly parallel and collective analog computations by observing global and local dynamics. Furthermore, we introduce spatial and temporal mutual information to quantitatively evaluate the system dynamics. The experimental results confirm the validity and efficiency of the proposed computational paradigm with the physical analog chaotic neuro-dynamics.

  5. How Science Students Can Learn about Unobservable Phenomena Using Computer-Based Analogies

    Science.gov (United States)

    Trey, L.; Khan, S.

    2008-01-01

    A novel instructional computer simulation that incorporates a dynamic analogy to represent Le Chatelier's Principle was designed to investigate the contribution of this feature to students' understanding. Two groups of 12th grade Chemistry students (n=15) interacted with the computer simulation during the study. Both groups did the same…

  6. Analog Computer-Aided Detection (CAD) information can be more effective than binary marks.

    Science.gov (United States)

    Cunningham, Corbin A; Drew, Trafton; Wolfe, Jeremy M

    2017-02-01

    In socially important visual search tasks, such as baggage screening and diagnostic radiology, experts miss more targets than is desirable. Computer-aided detection (CAD) programs have been developed specifically to improve performance in these professional search tasks. For example, in breast cancer screening, many CAD systems are capable of detecting approximately 90% of breast cancer, with approximately 0.5 false-positive detections per image. Nevertheless, benefits of CAD in clinical settings tend to be small (Birdwell, 2009) or even absent (Meziane et al., 2011; Philpotts, 2009). The marks made by a CAD system can be "binary," giving the same signal to any location where the signal is above some threshold. Alternatively, a CAD system presents an analog signal that reflects strength of the signal at a location. In the experiments reported, we compare analog and binary CAD presentations using nonexpert observers and artificial stimuli defined by two noisy signals: a visible color signal and an "invisible" signal that informed our simulated CAD system. We found that analog CAD generally yielded better overall performance than binary CAD. The analog benefit is similar at high and low target prevalence. Our data suggest that the form of the CAD signal can directly influence performance. Analog CAD may allow the computer to be more helpful to the searcher.

  7. Integrating Electrical Analogy and Computer Modeling of Groundwater Flow for Teaching Flownet Concepts

    Directory of Open Access Journals (Sweden)

    Murthy Kasi

    2013-10-01

    Full Text Available Laplace equation is the basic differential equation that governs the steady flow of a fluid through an isotropic and homogeneous porous medium and also the steady flow of current in a conducting medium. Therefore, a steady-state groundwater flow problem can be formulated as an analogous electrical current flow problem. A flow net, set of grids formed by orthogonally intersecting equipotential lines and flow lines, is a graphical solution to the equations of steady groundwater flow. By definition, flownet for the original groundwater problem and the corresponding analogous electrical problem should be similar. This feature allows the possibility of introducing the concepts of flownets to students using the easily demonstrable electrical counterpart of the problem in a laboratory setting. This paper discusses the efforts of the authors to widen the scope of an experiment already included in the Fluid Mechanics laboratory course of a Civil Engineering curriculum and to better teach flownet principles using the electrical analogy of groundwater flow problems. Students used a simple experimental setup to obtain flownets for selected groundwater flow situations with different boundary conditions using the electrical analogy concept. Students also used a groundwater flow computer model to obtain flownets for the same flow situations and compared the results. The laboratory lesson plan consisted of five steps: (i study and understand the selected physical groundwater problems, (ii conceptualize the corresponding analogous electrical problems (iii use the electrical analogy experimental setup to obtain flownets, (iv study and understand the mathematical formulation of the problems, and (v compare the analogous results with those obtained from a groundwater flow computer model. Sample results obtained by students are presented. The student feedback indicated that this approach resulted in an effective learning of the concepts involved.

  8. A mixed analog/digital chaotic neuro-computer system for quadratic assignment problems.

    Science.gov (United States)

    Horio, Yoshihiko; Ikeguchi, Tohru; Aihara, Kazuyuki

    2005-01-01

    We construct a mixed analog/digital chaotic neuro-computer prototype system for quadratic assignment problems (QAPs). The QAP is one of the difficult NP-hard problems, and includes several real-world applications. Chaotic neural networks have been used to solve combinatorial optimization problems through chaotic search dynamics, which efficiently searches optimal or near optimal solutions. However, preliminary experiments have shown that, although it obtained good feasible solutions, the Hopfield-type chaotic neuro-computer hardware system could not obtain the optimal solution of the QAP. Therefore, in the present study, we improve the system performance by adopting a solution construction method, which constructs a feasible solution using the analog internal state values of the chaotic neurons at each iteration. In order to include the construction method into our hardware, we install a multi-channel analog-to-digital conversion system to observe the internal states of the chaotic neurons. We show experimentally that a great improvement in the system performance over the original Hopfield-type chaotic neuro-computer is obtained. That is, we obtain the optimal solution for the size-10 QAP in less than 1000 iterations. In addition, we propose a guideline for parameter tuning of the chaotic neuro-computer system according to the observation of the internal states of several chaotic neurons in the network.

  9. VORCAM: A computer program for calculating vortex lift effect of cambered wings by the suction analogy

    Science.gov (United States)

    Lan, C. E.; Chang, J. F.

    1981-01-01

    A user's guide to an improved version of Woodward's chord plane aerodynamic panel computer code is presumed. The guide can be applied to cambered wings exhibiting edge separated flow, including those with leading edge vortex flow at subsonic and supersonic speeds. New orientations for the rotated suction force are employed based on the momentum principal. The supersonic suction analogy method is improved by using an effective angle of attack defined through a semiempirical method.

  10. Random matrix theory for the analysis of the performance of an analog computer: a scaling theory

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Hur, Asa; Feinberg, Joshua; Fishman, Shmuel; Siegelmann, Hava T

    2004-03-22

    The phase space flow of a dynamical system, leading to the solution of linear programming (LP) problems, is explored as an example of complexity analysis in an analog computation framework. In this framework, computation by physical devices and natural systems, evolving in continuous phase space and time (in contrast to the digital computer where these are discrete), is explored. A Gaussian ensemble of LP problems is studied. The convergence time of a flow to the fixed point representing the optimal solution, is computed. The cumulative distribution function of the convergence time is calculated in the framework of random matrix theory (RMT) in the asymptotic limit of large problem size. It is found to be a scaling function, of the form obtained in the theories of critical phenomena and Anderson localization. It demonstrates a correspondence between problems of computer science and physics.

  11. Analog series-based scaffolds: computational design and exploration of a new type of molecular scaffolds for medicinal chemistry

    Science.gov (United States)

    Dimova, Dilyana; Stumpfe, Dagmar; Hu, Ye; Bajorath, Jürgen

    2016-01-01

    Aim: Computational design of and systematic search for a new type of molecular scaffolds termed analog series-based scaffolds. Materials & methods: From currently available bioactive compounds, analog series were systematically extracted, key compounds identified and new scaffolds isolated from them. Results: Using our computational approach, more than 12,000 scaffolds were extracted from bioactive compounds. Conclusion: A new scaffold definition is introduced and a computational methodology developed to systematically identify such scaffolds, yielding a large freely available scaffold knowledge base.

  12. Classical Emulation of a Two-Qubit Quantum Computer with Analog Electronics

    Science.gov (United States)

    La Cour, Brian; Ostrove, Corey; Ott, Granville; Starkey, Michael; Wilson, Gary

    Abstract: The Hilbert space mathematical structure of a gate-based quantum computer may be reproduced by mapping the computational basis states to corresponding functions in the space of complex exponentials and identifying an inner product between any two such functions. The span of these complex basis exponentials may then identified with the finite-dimensional Hilbert space of a gate-based quantum computer. By using classical analog electronic components, such as four-quadrant multipliers and operational amplifiers, voltage signals representing arbitrary four-dimensional quantum states, along with the equivalent gate and measurement operations of a quantum computer have been physically realized through the corresponding circuitry. The fidelity of the emulation is measured using both a direct evaluation of the signal as well as through an emulation of quantum state tomography to infer the quantum state. We demonstrate that for both state synthesis and gate operations, our quantum emulation device is capable of achieving over 99% fidelity. This work was supported by the Office of Naval Research under Grant No. N00014-14-1-0323.

  13. Macromodeling for analog design and robustness boosting in bio-inspired computing models

    Science.gov (United States)

    Cuadri, J.; Linan, G.; Roca, E.; Rodriguez-Vazquez, A.

    2005-06-01

    Setting specifications for the electronic implementation of biological neural-network-like vision systems on-chip is not straightforward, neither it is to simulate the resulting circuit. The structure of these systems leads to a netlist of more than 100.000 nodes for a small array of 100x150 pixels. Moreover, introducing an optical input in the low level simulation is nowadays not feasible with standard electrical simulation environments. Given that, to accomplish the task of integrating those systems in silicon to build compact, low power consuming, and reliable systems, a previous step in the standard analog electronic design flux should be introduced. Here a methodology to make the translation from the biological model to circuit-level specifications for electronic design is proposed. The purpose is to include non ideal effects as mismatching, noise, leakages, supply degradation, feedthrough, and temperature of operation in a high level description of the implementation, in order to accomplish behavioural simulations that require less computational effort and resources. A particular case study is presented, the analog electronic implementation of the locust"s Lobula Giant Movement Detector (LGMD), a neural structure that fires a collision alarm based on visual information. The final goal is a collision threat detection vision system on-chip for automotive applications.

  14. Analog quantum computing (AQC) and the need for time-symmetric physics

    Science.gov (United States)

    Werbos, Paul J.; Dolmatova, Ludmilla

    2016-03-01

    This paper discusses what will be necessary to achieve the full potential capabilities of analog quantum computing (AQC), which is defined here as the enrichment of continuous-variable computing to include stochastic, nonunitary circuit elements such as dissipative spin gates and address the wider range of tasks emerging from new trends in engineering, such as approximation of stochastic maps, ghost imaging and new forms of neural networks and intelligent control. This paper focuses especially on what is needed in terms of new experiments to validate remarkable new results in the modeling of triple entanglement, and in creating a pathway which links fundamental theoretical work with hard core experimental work, on a pathway to AQC similar to the pathway to digital quantum computing already blazed by Zeilinger's group. It discusses the most recent experiments and reviews two families of alternative models based on the traditional eigenvector projection model of polarizers and on a new family of local realistic models based on Markov Random Fields across space-time adhering to the rules of time-symmetric physics. For both families, it reviews lumped parameter versions, continuous time extension and possibilities for extension to continuous space and time.

  15. Nano-scale Bias-scalable CMOS Analog Computational Circuits Using Margin Propagation

    Institute of Scientific and Technical Information of China (English)

    GU Ming

    2012-01-01

    Approximation techniques are useful for implementing pattern recognizers,communication decoders and sensory processing algorithms where computational precision is not critical to achieve the desired system level performance.In our previous work,we had proposed margin propagation (MP) as an efficient piece-wise linear (PWL) approximation technique to a Iog-sumexp function and had demonstrated its advantages for implementing probabilistic decoders.In this paper,we present a systematic and a generalized approach for synthesizing analog piecewiselinear (PWL) computing circuits using the MP principle.MP circuits use only addition,subtraction and threshold operations and hence can be implemented using universal conservation principles like the Kirchoff' s current law.Thus,unlike the conventional translinear CMOS currentmode circuits,the operation of the MP circuits are functionally similar in weak,moderate and strong inversion regimes of the MOS transistor making the design approach bias-scalable.This paper presents measured results from MP circuits prototyped in a 0.5 μm standard CMOS process verifying the bias-scalable property.As an example,we apply the synthesis approach towards designing linear classifiers and verify its performance using measured results.

  16. High-Precision CMOS Analog Computational Circuits Based on a New Linearly Tunable OTA

    Directory of Open Access Journals (Sweden)

    A. Naderi Saatlo

    2016-06-01

    Full Text Available Implementation of CMOS current-mode analog computational circuits are presented in this paper. A new Linearly Tunable OTA is employed in a modified structure as a basic building block for implementation of the circuits either linear or nonlinear functions. The proposed trans-conductance amplifier provides a constant Gm over a wide range of input voltage which allows the implementation of high precision computational circuits including square rooting, squaring, multiplication and division functions. Layout pattern of the proposed circuit confirms that the circuit can be implemented in 102μm*69μm active area. In order to verify the performance of the circuits, the post layout simulation results are presented through the use of HSPICE and Cadence with TSMC level 49 (BSIM3v3 parameters for 0.18 μm CMOS technology, where under supply voltage of 1.8 V, the maximum relative error of the circuits within 500 µA of input range is about 11 μA (2.2 % error and the THD remains as low as 1.2 % for the worst case. Moreover, the power dissipation of the complete structure is found to be 0.66 mW.

  17. Analog optical computing based on a dielectric meta-reflect array.

    Science.gov (United States)

    Chizari, Ata; Abdollahramezani, Sajjad; Jamali, Mohammad Vahid; Salehi, Jawad A

    2016-08-01

    In this Letter, we realize the concept of analog computing using an engineered gradient dielectric meta-reflect-array. The proposed configuration consists of individual subwavelength silicon nanobricks, in combination with a fused silica spacer and silver ground plane, realizing a reflection beam with full phase coverage of 2π degrees, as well as an amplitude range of 0 to 1. Spectrally overlapping electric and magnetic dipole resonances, such high-index dielectric metasurfaces can locally and independently manipulate the amplitude and phase of the incident electromagnetic wave. This practically feasible structure overcomes substantial limitations imposed by plasmonic metasurfaces such as absorption losses and low polarization conversion efficiency in the visible range. Using such CMOS-compatible and easily integrable platforms promises highly efficient ultrathin planar wave-based computing systems that circumvent the drawbacks of conventional bulky lens-based signal processors. Based on these key properties and the general concept of spatial Fourier transformation, we design and realize broadband mathematical operators such as the differentiator and integrator in the telecommunication wavelengths.

  18. COED Transactions, Vol. IX, No. 3, March 1977. Evaluation of a Complex Variable Using Analog/Hybrid Computation Techniques.

    Science.gov (United States)

    Marcovitz, Alan B., Ed.

    Described is the use of an analog/hybrid computer installation to study those physical phenomena that can be described through the evaluation of an algebraic function of a complex variable. This is an alternative way to study such phenomena on an interactive graphics terminal. The typical problem used, involving complex variables, is that of…

  19. Prediction of the noise of flow over a cylinder by direct computation and acoustic analogy

    Science.gov (United States)

    Mani, Ali; Wang, Meng; Moin, Parviz

    2007-11-01

    The sound field of flow over a circular cylinder at ReD=3900 and Ma=0.4 is evaluated using Large-Eddy Simulation (LES). The acoustic results computed directly from LES are compared with those obtained using an integral solution of the Ffowcs Williams-Hawkings (FW-H) equation in conjunction with the LES source field data. The modified FW-H solution is derived using a free-space Green function which accounts for the uniform mean flow and spanwise periodicity in the flow simulation. In the implementation of the FW-H solution, the cylinder surface and three porous surfaces with different distances from the cylinder are used as integration surfaces. The effect of turbulent flow structures crossing the integration boundary on the generation of artificial noise is studied. The quadrupole terms in the FW-H equation are found to be important in canceling artificial noise regardless of their physical significance. Alternative formulations of acoustic analogy that can better handle the boundary terms will be discussed.

  20. Combined Kinetic Studies and Computational Analysis on Kojic Acid Analogs as Tyrosinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Carlyle Ribeiro Lima

    2014-07-01

    Full Text Available Tyrosinase is a key enzyme in melanin synthesis and widely distributed in plants and animals tissues. In mammals, this enzyme is related to pigment production, involved in wound healing, primary immune response and it can also contribute to catecholamines synthesis in the brain. Consequently, tyrosinase enzyme represents an attractive and selective target in the field of the medicine, cosmetics and bio-insecticides. In this paper, experimental kinetics and computational analysis were used to study the inhibition of tyrosinase by analogous of Kojic acid. The main interactions occurring between inhibitors-tyrosinase complexes and the influence of divalent cation (Cu2+ in enzymatic inhibition were investigated by using molecular docking, molecular dynamic simulations and electrostatic binding free energy by using the Linear Interaction Energy (LIE method. The results showed that the electrostatic binding free energy are correlated with values of constant inhibition (r2 = 0.97.Thus, the model obtained here could contribute to future studies of this important system and, therefore, eventually facilitate development of tyrosinase inhibitors.

  1. Discovery of novel polyamine analogs with anti-protozoal activity by computer guided drug repositioning

    Science.gov (United States)

    Alberca, Lucas N.; Sbaraglini, María L.; Balcazar, Darío; Fraccaroli, Laura; Carrillo, Carolina; Medeiros, Andrea; Benitez, Diego; Comini, Marcelo; Talevi, Alan

    2016-04-01

    Chagas disease is a parasitic infection caused by the protozoa Trypanosoma cruzi that affects about 6 million people in Latin America. Despite its sanitary importance, there are currently only two drugs available for treatment: benznidazole and nifurtimox, both exhibiting serious adverse effects and limited efficacy in the chronic stage of the disease. Polyamines are ubiquitous to all living organisms where they participate in multiple basic functions such as biosynthesis of nucleic acids and proteins, proliferation and cell differentiation. T. cruzi is auxotroph for polyamines, which are taken up from the extracellular medium by efficient transporters and, to a large extent, incorporated into trypanothione (bis-glutathionylspermidine), the major redox cosubstrate of trypanosomatids. From a 268-compound database containing polyamine analogs with and without inhibitory effect on T. cruzi we have inferred classificatory models that were later applied in a virtual screening campaign to identify anti-trypanosomal compounds among drugs already used for other therapeutic indications (i.e. computer-guided drug repositioning) compiled in the DrugBank and Sweetlead databases. Five of the candidates identified with this strategy were evaluated in cellular models from different pathogenic trypanosomatids ( T. cruzi wt, T. cruzi PAT12, T. brucei and Leishmania infantum), and in vitro models of aminoacid/polyamine transport assays and trypanothione synthetase inhibition assay. Triclabendazole, sertaconazole and paroxetine displayed inhibitory effects on the proliferation of T. cruzi (epimastigotes) and the uptake of putrescine by the parasite. They also interfered with the uptake of others aminoacids and the proliferation of infective T. brucei and L. infantum (promastigotes). Trypanothione synthetase was ruled out as molecular target for the anti-parasitic activity of these compounds.

  2. Design and Synthesis of an Inositol Phosphate Analog Based on Computational Docking Studies.

    Science.gov (United States)

    Peng, Zhenghong; Maxwell, David; Sun, Duoli; Ying, Yunming; Schuber, Paul T; Bhanu Prasad, Basvoju A; Gelovani, Juri; Yung, Wai-Kwan Alfred; Bornmann, William G

    2014-01-28

    A virtual library of 54 inositol analog mimics of In(1,4,5)P3 has been docked, scored, and ranked within the binding site of human inositol 1,4,5-trisphosphate 3-kinase A (IP3-3KA). Chemical synthesis of the best scoring structure that also met distance criteria for 3'-OH to -P in Phosphate has been attempted along with the synthesis of (1S,2R,3S,4S)-3-fluoro-2,4-dihydroxycyclohexanecarboxylic acid as an inositol analog, useful for non-invasive visualization and quantitation of IP3-3KA enzymatic activity.

  3. Analogies of Information Security

    OpenAIRE

    Sole, Amund Bauck

    2016-01-01

    In this thesis it will be tested wither analogies and metaphors would make it easier to teach the fundamental subjects of information security and hacking to people with no previous background in computer science and only basic computer skills. This will be done by conducting interview on people with no background in computer science to see what analogies work the best for different topics in information security. From the analogy getting the best response, a small game will be designed with ...

  4. Grid cells generate an analog error-correcting code for singularly precise neural computation.

    Science.gov (United States)

    Sreenivasan, Sameet; Fiete, Ila

    2011-09-11

    Entorhinal grid cells in mammals fire as a function of animal location, with spatially periodic response patterns. This nonlocal periodic representation of location, a local variable, is unlike other neural codes. There is no theoretical explanation for why such a code should exist. We examined how accurately the grid code with noisy neurons allows an ideal observer to estimate location and found this code to be a previously unknown type of population code with unprecedented robustness to noise. In particular, the representational accuracy attained by grid cells over the coding range was in a qualitatively different class from what is possible with observed sensory and motor population codes. We found that a simple neural network can effectively correct the grid code. To the best of our knowledge, these results are the first demonstration that the brain contains, and may exploit, powerful error-correcting codes for analog variables.

  5. Therapeutically targeting guanylate cyclase-C: computational modeling of plecanatide, a uroguanylin analog.

    Science.gov (United States)

    Brancale, Andrea; Shailubhai, Kunwar; Ferla, Salvatore; Ricci, Antonio; Bassetto, Marcella; Jacob, Gary S

    2017-04-01

    Plecanatide is a recently developed guanylate cyclase-C (GC-C) agonist and the first uroguanylin analog designed to treat chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C). GC-C receptors are found across the length of the intestines and are thought to play a key role in fluid regulation and electrolyte balance. Ligands of the GC-C receptor include endogenous agonists, uroguanylin and guanylin, as well as diarrheagenic, Escherichia coli heat-stable enterotoxins (ST). Plecanatide mimics uroguanylin in its 2 disulfide-bond structure and in its ability to activate GC-Cs in a pH-dependent manner, a feature associated with the presence of acid-sensing residues (Asp2 and Glu3). Linaclotide, a synthetic analog of STh (a 19 amino acid member of ST family), contains the enterotoxin's key structural elements, including the presence of three disulfide bonds. Linaclotide, like STh, activates GC-Cs in a pH-independent manner due to the absence of pH-sensing residues. In this study, molecular dynamics simulations compared the stability of plecanatide and linaclotide to STh. Three-dimensional structures of plecanatide at various protonation states (pH 2.0, 5.0, and 7.0) were simulated with GROMACS software. Deviations from ideal binding conformations were quantified using root mean square deviation values. Simulations of linaclotide revealed a rigid conformer most similar to STh. Plecanatide simulations retained the flexible, pH-dependent structure of uroguanylin. The most active conformers of plecanatide were found at pH 5.0, which is the pH found in the proximal small intestine. GC-C receptor activation in this region would stimulate intraluminal fluid secretion, potentially relieving symptoms associated with CIC and IBS-C.

  6. TOWARDS A MATHEMATICAL THEORY OF ANALOGY

    OpenAIRE

    Haraguchi, Makoto

    1985-01-01

    This paper presents a mathematical theory of analogy, which should be a basis in developing analogical reasoning by a computer. The analogy is a partial identity between two sets of facts. In order to compare several analogies, we introduce an ordering of analogies, and we define two types of optimal analogies, maximal analogies and greatest ones. We show a condition under which the greatest analogy exists, and also present a top-down procedure to find the maximal analogies.

  7. Automated design of analog and high-frequency circuits a computational intelligence approach

    CERN Document Server

    Liu, Bo; Fernández, Francisco V

    2014-01-01

    Computational intelligence techniques are becoming more and more important for automated problem solving nowadays. Due to the growing complexity of industrial applications and the increasingly tight time-to-market requirements, the time available for thorough problem analysis and development of tailored solution methods is decreasing. There is no doubt that this trend will continue in the foreseeable future. Hence, it is not surprising that robust and general automated problem solving methods with satisfactory performance are needed.

  8. Impaired oral reading in two atypical dyslexics: a comparison with a computational lexical-analogy model.

    Science.gov (United States)

    Marchand, Yannick; Friedman, Rhonda B

    2005-06-01

    A computational model of reading was developed based upon the notion that the structural relationship between orthography and phonology is of greater importance than the dimension of semantics for the reading aloud of single words. Degradation of this model successfully simulated the reading performance of two patients with atypical acquired dyslexia. The first patient CAV, studied and described in the literature by Warrington in 1981, presented with unusual concrete word dyslexia, i.e., he had a category-specific reading deficit for concrete words compared with abstract words. The second patient BG is a phonological dyslexic who, although displaying a strong concreteness effect (concrete words read better than abstract words), was able to read functors individually perfectly well, a pattern that is rarely if ever seen. The computational model was used to generate a set of words for which it was predicted that BG would show no concreteness effect. The results of BG's reading of these words were consistent with this prediction, thereby providing greater support for the validity of the model. It is concluded that a computational approach that attempts not only to reproduce the core symptoms of the major varieties of acquired dyslexia but also to simulate clinical data from specific patients has much to contribute to the understanding of cognitive deficits and to the design of effective rehabilitation strategies.

  9. Computational modelling of genome-wide [corrected] transcription assembly networks using a fluidics analogy.

    Directory of Open Access Journals (Sweden)

    Yousry Y Azmy

    Full Text Available Understanding how a myriad of transcription regulators work to modulate mRNA output at thousands of genes remains a fundamental challenge in molecular biology. Here we develop a computational tool to aid in assessing the plausibility of gene regulatory models derived from genome-wide expression profiling of cells mutant for transcription regulators. mRNA output is modelled as fluid flow in a pipe lattice, with assembly of the transcription machinery represented by the effect of valves. Transcriptional regulators are represented as external pressure heads that determine flow rate. Modelling mutations in regulatory proteins is achieved by adjusting valves' on/off settings. The topology of the lattice is designed by the experimentalist to resemble the expected interconnection between the modelled agents and their influence on mRNA expression. Users can compare multiple lattice configurations so as to find the one that minimizes the error with experimental data. This computational model provides a means to test the plausibility of transcription regulation models derived from large genomic data sets.

  10. Retrieval of Earthshine Spectra Using Evolutionary Computational Methods as Analogs for Extra-Solar Planetary Spectra

    Science.gov (United States)

    Terrile, R. J.; Tinetti, G.; Lee, S.; Fink, W.; Huntsberger, T.; von Allmen, P.; Tisdale, E. R.

    2006-05-01

    The spectral information provided by the next generation of extra-solar planet exploration missions will be averaged over the visible disk and the exposure time. Most probably, the interpretation of the observed spectra will not be unique, but families of solutions will provide equally good explanations of the spectral features (degeneracy). Traditional retrieval techniques developed to study the environments of planets in our solar system are inadequate to analyze disk/time-averaged spectra because they assume homogeneous environments, short observational time scales and search only for solutions belonging to the local domain of the initial conditions. We developed an innovative technique that couples evolutionary computational methods to a 3D model that simulates the spectral response of the planet rotating (Tinetti et al., 2005). We have performed a set of preliminary experiments in retrieving the earthshine spectrum recorded by Woolf et al. (2002): nine weighting parameters were retrieved, corresponding to different surface/cloud types (ocean, forest, grass, ground, tundra, ice, high/medium/low clouds) uniformly distributed over 48 planetary pixels. Two distinct retrieval experiments were run: i) evolution of one large solution population with 1000 individuals and ii) evolution of multiple solution islands with 100 individuals in each island. These two experiments returned over 2700 automatically generated retrievals satisfying the error criterion (fitness) of 10% least squares match to the observed spectra. The spectral retrieval procedure with this reduced set of parameters already resulted in a high quality fit of the earthshine spectrum, in agreement with ground truth. The retrieved solutions were divided into classes of spectral fit using clustering tools, which helped visualize the degeneracy in the set of solutions. We have also repeated the experiment using non-uniformly distributed 3 cloud types over ground- truth surface types in 22 illuminated pixels

  11. Lunar Analog

    Science.gov (United States)

    Cromwell, Ronita L.

    2009-01-01

    In this viewgraph presentation, a ground-based lunar analog is developed for the return of manned space flight to the Moon. The contents include: 1) Digital Astronaut; 2) Bed Design; 3) Lunar Analog Feasibility Study; 4) Preliminary Data; 5) Pre-pilot Study; 6) Selection of Stockings; 7) Lunar Analog Pilot Study; 8) Bed Design for Lunar Analog Pilot.

  12. Design of a Robust, Computation-Efficient and Secure 3P-EKE Protocol using Analogous Message Transmission

    Directory of Open Access Journals (Sweden)

    Archana Raghuvamshi

    2016-05-01

    Full Text Available In this modern era of digital communication even a trivial task needs to be performed over internet which is not secure. Many cryptographic algorithms existed to provide security which facilitates secure communication through internet. As these algorithms need a secret session key, it is required to interchange this key in a secure way. In two-party communication, two clients initially share a low random (entropy password through a secure channel to establish a secret session key. But this paradigm necessitates high maintenance of passwords, since each communicating pair requires separate passwords to establish a secure session key. In three-party communication network, each communication party shares a password with the trusted third-party (server to exchange a secret session key. The beauty of this setting is that, even a server does not know the session key. The Password Authenticated Encrypted Key Exchange (PA-EKE protocols have attracted a lot of curiosity to authors to propose various two-party and three-party PA-EKE protocols. Security flaws in various protocols proposed by Chang-Chang, Yoon-Yoo, PSRJ and Raj et al. inspired to design a robust, computationally efficient and highly secure protocol. This paper is an attempt to propose a secure and novel Password Authenticated 3P-EKE protocol using XOR operations and analogous (parallel message transmission. The proposed protocol is easy to design and more secured against all types of attacks like password guessing, replay, pre-play, server spoofing etc. which made this protocol special.

  13. Attempted Isolation, Spectroscopic Characterization, and Computational Study of Diazirinone (N2CO), its Analogs, and their Precursors

    Science.gov (United States)

    Esselman, Brian J.; Nolan, Alex M.; Amberger, Brent K.; Shaffer, Chris J.; Woods, R. Claude; Stanton, John F.; McMahon, Robert J.

    2010-11-01

    Intrigued by the 2005 reported synthesis of diazirinone, we carried out further experimental and theoretical studies aimed at the detailed matrix-isolation and millimeter-wave spectroscopic characterizations. Diazirinone is a peculiar isoconjugate of two very stable molecules, CO and N2, which may be of astrochemical interest. Unfortunately, the previous reported methods of diazirinone generation did not yield this species, but rather its decomposition products. Encouraged by the many computational studies of the N2CO potential energy surface that all found diazirinone to be the lowest energy isomer, save its decomposition products, we proposed a new method of preparation of diazirinone from the photolysis or thermolysis of carbonyl diazide by loss of two nitrogen molecules. We were able to generate the highly explosive carbonyl diazide in sufficient yield from the reaction of triphosgene and sodium azide. This has allowed us to obtain a matrix-isolation and gas phase IR spectrum of carbonyl diazide which has a gas-phase lifetime of several days. We are currently engaged in the safe purification and distillation of our sample and obtaining a millimeter-wave spectrum of carbonyl diazide. We will attempt to photolyze or thermolyze this molecule to release diazirinone and characterize it by millimeter-wave spectroscopy to pave the way for possible astrochemical detection. In order to provide better mechanistic insight into the decomposition of carbonyl diazide to diazirinone, we have engaged in a DFT and ab initio computational study of several possible pathways. Our preliminary results suggest that of the pathways studied, a step-wise process in which an acyclic CON4 species is generated by loss of nitrogen followed by possible rearrangement and further loss of N2 is most likely. These results will be compared to the analogous reactions for azirinone (HC2NO), our next likely synthetic and spectroscopic target. The millimeter-wave absorption spectrometer used in this

  14. Signal-to-noise ratio estimation in digital computer simulation of lowpass and bandpass systems with applications to analog and digital communications, volume 3

    Science.gov (United States)

    Tranter, W. H.; Turner, M. D.

    1977-01-01

    Techniques are developed to estimate power gain, delay, signal-to-noise ratio, and mean square error in digital computer simulations of lowpass and bandpass systems. The techniques are applied to analog and digital communications. The signal-to-noise ratio estimates are shown to be maximum likelihood estimates in additive white Gaussian noise. The methods are seen to be especially useful for digital communication systems where the mapping from the signal-to-noise ratio to the error probability can be obtained. Simulation results show the techniques developed to be accurate and quite versatile in evaluating the performance of many systems through digital computer simulation.

  15. Solution of the transfer functions and the linear networks by an analog computer; Resolution des fonctions de transfert et des reseaux lineaires sur calculateur analogique

    Energy Technology Data Exchange (ETDEWEB)

    Bras, D

    1967-09-27

    This study presents five methods used to realize a transfer function on analog computer - method of operational amplifiers - method of successive integrations - method of the auxiliary variable - method of the Horner decomposition - method of the direct analog transposition. The method that seems to us the most interesting, this one of Horner, is exposed with some complements. The last method presents the study of a linear network (mechanical, electronic) by direct analog transposition, without having to calculate its transfer function. Several aspects are studied the economy or the material type, the simpleness of implementing the adaptation of coefficients to the computer, the introduction of initial conditions of input and output functions. Every method presented is discussed in function of these problems. The precision of the result is not studied here, but we can indicate that the methods treated here, do not include approximations other than these ones of the computer elements. [French] Cette etude presente cinq methodes utilisees pour realiser une fonction de transfert quelconque sur calculateur analogique - methode des Amplificateurs operationnels - methode des integrations successives - methode de la variable auxiliaire - methode de la decomposition de Horner - methode de la transposition analogique directe. La methode qui nous semble la plus interessante, celle de Horner, est exposee avec quelques complements. La derniere methode presente l'etude d'un reseau lineaire (mecanique, electronique...) par transposition analogique directe, sans avoir a calculer sa fonction de transfert. Plusieurs aspects sont etudies l'economie ou le type de materiel, la simplicite de mise en oeuvre l'adaptation des coefficients au calculateur, l'introduction des conditions initiales des fonctions d'entree et de sortie. Chaque methode presentee est discutee en fonction de ces problemes. La precision du resultat n'est pas etudiee ici, mais on

  16. Prospects of a mathematical theory of human behavior in complex man-machine systems tasks. [time sharing computer analogy of automobile driving

    Science.gov (United States)

    Johannsen, G.; Rouse, W. B.

    1978-01-01

    A hierarchy of human activities is derived by analyzing automobile driving in general terms. A structural description leads to a block diagram and a time-sharing computer analogy. The range of applicability of existing mathematical models is considered with respect to the hierarchy of human activities in actual complex tasks. Other mathematical tools so far not often applied to man machine systems are also discussed. The mathematical descriptions at least briefly considered here include utility, estimation, control, queueing, and fuzzy set theory as well as artificial intelligence techniques. Some thoughts are given as to how these methods might be integrated and how further work might be pursued.

  17. Computer-assisted combinatorial design of bicyclic thymidine analogs as inhibitors of Mycobacterium tuberculosis thymidine monophosphate kinase

    Science.gov (United States)

    Frecer, Vladimir; Seneci, Pierfausto; Miertus, Stanislav

    2011-01-01

    Thymidine monophosphate kinase (TMPKmt) is an essential enzyme for nucleotide metabolism in Mycobacterium tuberculosis, and thus an attractive target for novel antituberculosis agents. In this work, we have explored the chemical space around the 2',3'-bicyclic thymidine nucleus by designing and in silico screening of a virtual focused library selected via structure based methods to identify more potent analogs endowed with favorable ADME-related properties. In all the library members we have exchanged the ribose ring of the template with a cyclopentane moiety that is less prone to enzymatic degradation. In addition, we have replaced the six-membered 2',3'-ring by a number of five-membered and six-membered heterocyclic rings containing alternative proton donor and acceptor groups, to exploit the interaction with the carboxylate groups of Asp9 and Asp163 as well as with several cationic residues present in the vicinity of the TMPKmt binding site. The three-dimensional structure of the TMPKmt complexed with 5-hydroxymethyl-dUMP, an analog of dTMP, was employed to develop a QSAR model, to parameterize a scoring function specific for the TMPKmt target and to select analogues which display the highest predicted binding to the target. As a result, we identified a small highly focused combinatorial subset of bicyclic thymidine analogues as virtual hits that are predicted to inhibit the mycobacterial TMPK in the submicromolar concentration range and to display favorable ADME-related properties.

  18. Hapten-antibody recognition studies in competitive immunoassay of α-zearalanol analogs by computational chemistry and Pearson Correlation analysis.

    Science.gov (United States)

    Wang, Zhanhui; Luo, Pengjie; Cheng, Linli; Zhang, Suxia; Shen, Jianzhong

    2011-01-01

    The molecular recognition of hapten-antibody is a fundamental event in competitive immunoassay, which guarantees the sensitivity and specificity of immunoassay for the detection of haptens. The aim of this study is to investigate the correlation between binding ability of one monoclonal antibody, 1H9B4, recognizing and the molecular aspects of α-zearalanol analogs. The mouse-derived monoclonal antibody was produced by using α-zearalanol conjugated to bovine serum albumin as an immunogen. The antibody recognition abilities, expressed as IC(50) values, were determined by a competitive ELISA. All of the hapten molecules were optimized by Density Function Theory (DFT) at B3LYP/ 6-31G* level and the conformation and electrostatic molecular isosurface were employed to explain the molecular recognition between α-zearalanol analogs and antibody 1H9B4. Pearson Correlation analysis between molecular descriptors and IC(50) values was qualitatively undertaken and the results showed that one molecular descriptor, surface of the hapten molecule, clearly demonstrated linear relationship with antibody recognition ability, where the relationship coefficient was 0.88 and the correlation was significant at p Pearson Correlation analysis can be used as tool to help the immunochemistries better understand the processing of antibody recognition of hapten molecules in competitive immunoassay.

  19. The Application of Analogy in Teaching Computer Network%类比教学在计算机网络教学中的运用

    Institute of Scientific and Technical Information of China (English)

    安子强

    2014-01-01

    针对计算机网络课程内容多、概念抽象等特点,探讨了运用类比手段把抽象问题具体化的方法,以帮助学生掌握和理解抽象概念。教学实践表明,类比教学能使复杂、抽象的问题形象化,学生易于接受,在学习过程中还能触类旁通,提高了学生自主学习的能力。%Computer network course has the characteristics of rich theoretical knowledge and abstract concepts .In this article ,the author discussed the method of specifying the abstract concepts to help students master and comprehend the concepts .Teaching practice proved that analog teaching can visualize the complicated and abstract problems ,and help students understand and analogize ,and improve the self‐regulated learning .

  20. Analog earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, R.B. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)

    1995-09-01

    Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository.

  1. Computational and biochemical docking of the irreversible cocaine analog RTI 82 directly demonstrates ligand positioning in the dopamine transporter central substrate-binding site.

    Science.gov (United States)

    Dahal, Rejwi Acharya; Pramod, Akula Bala; Sharma, Babita; Krout, Danielle; Foster, James D; Cha, Joo Hwan; Cao, Jianjing; Newman, Amy Hauck; Lever, John R; Vaughan, Roxanne A; Henry, L Keith

    2014-10-24

    The dopamine transporter (DAT) functions as a key regulator of dopaminergic neurotransmission via re-uptake of synaptic dopamine (DA). Cocaine binding to DAT blocks this activity and elevates extracellular DA, leading to psychomotor stimulation and addiction, but the mechanisms by which cocaine interacts with DAT and inhibits transport remain incompletely understood. Here, we addressed these questions using computational and biochemical methodologies to localize the binding and adduction sites of the photoactivatable irreversible cocaine analog 3β-(p-chlorophenyl)tropane-2β-carboxylic acid, 4'-azido-3'-iodophenylethyl ester ([(125)I]RTI 82). Comparative modeling and small molecule docking indicated that the tropane pharmacophore of RTI 82 was positioned in the central DA active site with an orientation that juxtaposed the aryliodoazide group for cross-linking to rat DAT Phe-319. This prediction was verified by focused methionine substitution of residues flanking this site followed by cyanogen bromide mapping of the [(125)I]RTI 82-labeled mutants and by the substituted cysteine accessibility method protection analyses. These findings provide positive functional evidence linking tropane pharmacophore interaction with the core substrate-binding site and support a competitive mechanism for transport inhibition. This synergistic application of computational and biochemical methodologies overcomes many uncertainties inherent in other approaches and furnishes a schematic framework for elucidating the ligand-protein interactions of other classes of DA transport inhibitors.

  2. 模拟KVM技术在计算机集群管理中的应用%Application of Analog KVM Technology in Management of Computer Cluster

    Institute of Scientific and Technical Information of China (English)

    耿士华; 吴之光; 梁记斌

    2014-01-01

    KVM is an abbreviation of the keyboard, video and mouse. The key idea of KVM technology is that by more efficient management of computer cluster with less keyboard, monitor and mouse, the efficiency of worker improves and the cost of management reduces. The research of the paper is discussed from the superiority of analog KVM technology, the key technology and its application in the computer cluster management.%KVM是键盘(Keyboard)、视频(Video)和鼠标(Mouse)的缩写,KVM技术核心思想是通过少量的键盘、鼠标和显示器配置,实现多主机计算集群系统的高可管理性,提高管理人员工作效率,降低管理成本。本文主要从模拟KVM技术的优越性、关键技术、在计算机集群管理中的应用等方面进行论述。

  3. Computational modeling of the class I low-mass protostar Elias 29 applying optical constants of ices processed by high energy cosmic ray analogs

    CERN Document Server

    Rocha, W R M

    2015-01-01

    We present the study of the effects of high energy cosmic rays (CRs) over the astrophysical ices, observed toward the embedded class I protostar Elias 29, by using computational modeling and laboratory data. Its spectrum was observed with {\\it Infrared Space Observatory - ISO}, covering 2.3 - 190 $\\mu$m. The modeling employed the three-dimensional Monte Carlo radiative transfer code RADMC-3D (Dullemond et al. 2012) and laboratory data of bombarded ice grains by CRs analogs, and unprocessed ices (not bombarded). We are assuming that Elias 29 has a self-irradiated disk with inclination $i =$ 60$^{\\circ}$, surrounded by an envelope with bipolar cavity. The results show that absorption features toward Elias 29, are better reproduced by assuming a combination between unprocessed astrophysical ices at low temperature (H$_2$O, CO, CO$_2$) and bombarded ices (H$_2$O:CO$_2$) by high energy CRs. Evidences of the ice processing around Elias 29 can be observed by the good fitting around 5.5-8.0 $\\mu$m, by polar and apola...

  4. Molecular modeling of fentanyl analogs

    Directory of Open Access Journals (Sweden)

    LJILJANA DOSEN-MICOVIC

    2004-11-01

    Full Text Available Fentanyl is a highly potent and clinically widely used narcotic analgesic. A large number of its analogs have been synthesized, some of which (sufentanil and alfentanyl are also in clinical use. Theoretical studies, in recent years, afforded a better understanding of the structure-activity relationships of this class of opiates and allowed insight into the molecular mechanism of the interactions of fentanyl analogs with their receptors. An overview of the current computational techniques for modeling fentanyl analogs, their receptors and ligand-receptor interactions is presented in this paper.

  5. Analog electronic neural network circuits

    Energy Technology Data Exchange (ETDEWEB)

    Graf, H.P.; Jackel, L.D. (AT and T Bell Labs., Holmdel, NJ (USA))

    1989-07-01

    The large interconnectivity and moderate precision required in neural network models present new opportunities for analog computing. This paper discusses analog circuits for a variety of problems such as pattern matching, optimization, and learning. Most of the circuits build so far are relatively small, exploratory designs. The most mature circuits are those for template matching. Chips performing this function are now being applied to pattern recognition problems.

  6. Analog-Computer Investigation of Effects of Friction and Preload on the Dynamic Longitudinal Characteristics of a Pilot-Airplane Combination

    Science.gov (United States)

    Crane, Harold L.

    1961-01-01

    With an electric analog computer, an investigation has been made of the effects of control frictions and preloads on the transient longitudinal response of a fighter airplane during abrupt small attitude corrections. The simulation included the airplane dynamics, powered control system, feel system, and a simple linearized pseudopilot. Control frictions at the stick pivot and at the servo valve as well as preloads of the stick and valve were considered individually and in combinations. It is believed that the results which are presented in the form of time histories and vector diagrams present a more detailed illustration of the effects of stray forces and compensating forces in the longitudinal control system than has previously been available. Consistent with the results of previous studies, the present results show that any of these four friction and preload forces caused some deterioration of the response. However, even a small amount of valve friction caused an oscillatory pitching response during which the phasing of the valve friction was such that it caused energy to be fed into the pitching oscillation of the air-plane. Of the other friction and preload forces which were considered, it was found that stick preload was close to 180 deg. out of phase with valve friction and thus could compensate in large measure for valve friction as long as the cycling of the stick encompassed the trim point. Either stick friction or valve preload provided a smaller stabilizing effect primarily through a reduction in the amplitude of the resultant force vector acting on the control system. Some data were obtained on the effects of friction when the damping or inertia of the control system or the pilot lag was varied.

  7. Computers in Information Sciences: On-Line Systems.

    Science.gov (United States)

    COMPUTERS, *BIBLIOGRAPHIES, *ONLINE SYSTEMS, * INFORMATION SCIENCES , DATA PROCESSING, DATA MANAGEMENT, COMPUTER PROGRAMMING, INFORMATION RETRIEVAL, COMPUTER GRAPHICS, DIGITAL COMPUTERS, ANALOG COMPUTERS.

  8. High-speed and high-resolution analog-to-digital and digital-to-analog converters

    NARCIS (Netherlands)

    van de Plassche, R.J.

    1989-01-01

    Analog-to-digital and digital-to-analog converters are important building blocks connecting the analog world of transducers with the digital world of computing, signal processing and data acquisition systems. In chapter two the converter as part of a system is described. Requirements of analog filte

  9. Design of Multifunctional Platform Analog Computer Peripherals Based on Android Smartphone%基于Android智能手机的模拟计算机外设的多功能平台设计

    Institute of Scientific and Technical Information of China (English)

    罗圆; 刘世鑫; 瞿绍军

    2014-01-01

    随着计算技术和通信技术的快速发展,人类正逐步进入普适计算(Ubiquitous Computing)时代。而智能空间正是普适计算本质特点的一种具体而集中的体现,智能手机在其中可以获得增强化的个性服务。论文实现了一种基于Android智能手机的模拟电脑外设的多功能平台,手机和电脑端通过TCP/IP协议连接,使得用户在一定的距离内用手机远程的控制电脑。%With the rapid development of computer technology and communication technology, human beings is gradually enter⁃ing the Ubiquitous Computing age. The Smart Space is a specific and concentrated expression of an essential feature of pervasive computing.Due to them,Intelligent phone can get personalized service. This paper realizes a multifunctional platform analog computer peripherals based on Android smartphone, mobile phones and computer connected via TCP/IP protocol, allowing us⁃ers remote control the computer at the appropriate distance using a mobile phone.

  10. Learning by Analogy: Discriminating between Potential Analogs

    Science.gov (United States)

    Richland, Lindsey E.; McDonough, Ian M.

    2010-01-01

    The ability to successfully discriminate between multiple potentially relevant source analogs when solving new problems is crucial to proficiency in a mathematics domain. Experimental findings in two different mathematical contexts demonstrate that providing cues to support comparative reasoning during an initial instructional analogy, relative to…

  11. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  12. DESIGN AND ANALOG VLSI IMPLEMENTATION OF ARTIFICIAL NEURAL NETWORK

    OpenAIRE

    2011-01-01

    Nature has evolved highly advanced systems capable of performing complex computations, adoption and learning using analog computations. Furthermore nature has evolved techniques to deal with imprecise analog computations by using redundancy and massive connectivity. In this paper we are making use of Artificial Neural Network to demonstrate the way in which the biological system processes in analog domain. We are using 180nm CMOS VLSI technology for implementing circuits which ...

  13. Synaptic dynamics in analog VLSI.

    Science.gov (United States)

    Bartolozzi, Chiara; Indiveri, Giacomo

    2007-10-01

    Synapses are crucial elements for computation and information transfer in both real and artificial neural systems. Recent experimental findings and theoretical models of pulse-based neural networks suggest that synaptic dynamics can play a crucial role for learning neural codes and encoding spatiotemporal spike patterns. Within the context of hardware implementations of pulse-based neural networks, several analog VLSI circuits modeling synaptic functionality have been proposed. We present an overview of previously proposed circuits and describe a novel analog VLSI synaptic circuit suitable for integration in large VLSI spike-based neural systems. The circuit proposed is based on a computational model that fits the real postsynaptic currents with exponentials. We present experimental data showing how the circuit exhibits realistic dynamics and show how it can be connected to additional modules for implementing a wide range of synaptic properties.

  14. The Role of Causal Models in Analogical Inference

    Science.gov (United States)

    Lee, Hee Seung; Holyoak, Keith J.

    2008-01-01

    Computational models of analogy have assumed that the strength of an inductive inference about the target is based directly on similarity of the analogs and in particular on shared higher order relations. In contrast, work in philosophy of science suggests that analogical inference is also guided by causal models of the source and target. In 3…

  15. Structured Analog CMOS Design

    CERN Document Server

    Stefanovic, Danica

    2008-01-01

    Structured Analog CMOS Design describes a structured analog design approach that makes it possible to simplify complex analog design problems and develop a design strategy that can be used for the design of large number of analog cells. It intentionally avoids treating the analog design as a mathematical problem, developing a design procedure based on the understanding of device physics and approximations that give insight into parameter interdependences. The proposed transistor-level design procedure is based on the EKV modeling approach and relies on the device inversion level as a fundament

  16. Repeatable, accurate, and high speed multi-level programming of memristor 1T1R arrays for power efficient analog computing applications

    Science.gov (United States)

    Merced-Grafals, Emmanuelle J.; Dávila, Noraica; Ge, Ning; Williams, R. Stanley; Strachan, John Paul

    2016-09-01

    Beyond use as high density non-volatile memories, memristors have potential as synaptic components of neuromorphic systems. We investigated the suitability of tantalum oxide (TaOx) transistor-memristor (1T1R) arrays for such applications, particularly the ability to accurately, repeatedly, and rapidly reach arbitrary conductance states. Programming is performed by applying an adaptive pulsed algorithm that utilizes the transistor gate voltage to control the SET switching operation and increase programming speed of the 1T1R cells. We show the capability of programming 64 conductance levels with cells in the 1T1R array showing robustness to cell-to-cell variability. In general, the proposed algorithm results in approximately 10× improvement in programming speed over standard algorithms that do not use the transistor gate to control memristor switching. In addition, after only two programming pulses (an initialization pulse followed by a programming pulse), the resulting conductance values are within 12% of the target values in all cases. Finally, endurance of more than 106 cycles is shown through open-loop (single pulses) programming across multiple conductance levels using the optimized gate voltage of the transistor. These results are relevant for applications that require high speed, accurate, and repeatable programming of the cells such as in neural networks and analog data processing.

  17. Repeatable, accurate, and high speed multi-level programming of memristor 1T1R arrays for power efficient analog computing applications.

    Science.gov (United States)

    Merced-Grafals, Emmanuelle J; Dávila, Noraica; Ge, Ning; Williams, R Stanley; Strachan, John Paul

    2016-09-09

    Beyond use as high density non-volatile memories, memristors have potential as synaptic components of neuromorphic systems. We investigated the suitability of tantalum oxide (TaOx) transistor-memristor (1T1R) arrays for such applications, particularly the ability to accurately, repeatedly, and rapidly reach arbitrary conductance states. Programming is performed by applying an adaptive pulsed algorithm that utilizes the transistor gate voltage to control the SET switching operation and increase programming speed of the 1T1R cells. We show the capability of programming 64 conductance levels with programming speed and programming error. The algorithm is also utilized to program 16 conductance levels on a population of cells in the 1T1R array showing robustness to cell-to-cell variability. In general, the proposed algorithm results in approximately 10× improvement in programming speed over standard algorithms that do not use the transistor gate to control memristor switching. In addition, after only two programming pulses (an initialization pulse followed by a programming pulse), the resulting conductance values are within 12% of the target values in all cases. Finally, endurance of more than 10(6) cycles is shown through open-loop (single pulses) programming across multiple conductance levels using the optimized gate voltage of the transistor. These results are relevant for applications that require high speed, accurate, and repeatable programming of the cells such as in neural networks and analog data processing.

  18. Analogy in CLAM

    OpenAIRE

    Melis, Erica

    1999-01-01

    CL A M is a proof planner, developed by the Dream group in Edinburgh,that mainly operates for inductive proofs. This paper addresses the questionhow an analogy model that I developed independently of CL A M can beapplied to CL A M and it presents analogy-driven proof plan construction as acontrol strategy of CL A M . This strategy is realized as a derivational analogythat includes the reformulation of proof plans. The analogical replay checkswhether the reformulated justifications of the sour...

  19. Analog circuit design

    CERN Document Server

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  20. A putative RNA-interference-based immune system in prokaryotes: computational analysis of the predicted enzymatic machinery, functional analogies with eukaryotic RNAi, and hypothetical mechanisms of action

    Directory of Open Access Journals (Sweden)

    Wolf Yuri I

    2006-03-01

    Full Text Available Abstract Background All archaeal and many bacterial genomes contain Clustered Regularly Interspaced Short Palindrome Repeats (CRISPR and variable arrays of the CRISPR-associated (cas genes that have been previously implicated in a novel form of DNA repair on the basis of comparative analysis of their protein product sequences. However, the proximity of CRISPR and cas genes strongly suggests that they have related functions which is hard to reconcile with the repair hypothesis. Results The protein sequences of the numerous cas gene products were classified into ~25 distinct protein families; several new functional and structural predictions are described. Comparative-genomic analysis of CRISPR and cas genes leads to the hypothesis that the CRISPR-Cas system (CASS is a mechanism of defense against invading phages and plasmids that functions analogously to the eukaryotic RNA interference (RNAi systems. Specific functional analogies are drawn between several components of CASS and proteins involved in eukaryotic RNAi, including the double-stranded RNA-specific helicase-nuclease (dicer, the endonuclease cleaving target mRNAs (slicer, and the RNA-dependent RNA polymerase. However, none of the CASS components is orthologous to its apparent eukaryotic functional counterpart. It is proposed that unique inserts of CRISPR, some of which are homologous to fragments of bacteriophage and plasmid genes, function as prokaryotic siRNAs (psiRNA, by base-pairing with the target mRNAs and promoting their degradation or translation shutdown. Specific hypothetical schemes are developed for the functioning of the predicted prokaryotic siRNA system and for the formation of new CRISPR units with unique inserts encoding psiRNA conferring immunity to the respective newly encountered phages or plasmids. The unique inserts in CRISPR show virtually no similarity even between closely related bacterial strains which suggests their rapid turnover, on evolutionary scale

  1. Challenges in Using Analogies

    Science.gov (United States)

    Lin, Shih-Yin; Singh, Chandralekha

    2011-01-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same…

  2. Hydraulic Capacitor Analogy

    Science.gov (United States)

    Baser, Mustafa

    2007-01-01

    Students have difficulties in physics because of the abstract nature of concepts and principles. One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding. According to Iding, analogies are consistent with the tenets of constructivist learning…

  3. Troubleshooting analog circuits

    CERN Document Server

    Pease, Robert A

    1991-01-01

    Troubleshooting Analog Circuits is a guidebook for solving product or process related problems in analog circuits. The book also provides advice in selecting equipment, preventing problems, and general tips. The coverage of the book includes the philosophy of troubleshooting; the modes of failure of various components; and preventive measures. The text also deals with the active components of analog circuits, including diodes and rectifiers, optically coupled devices, solar cells, and batteries. The book will be of great use to both students and practitioners of electronics engineering. Other

  4. TV Analog Station Transmitters

    Data.gov (United States)

    Department of Homeland Security — This file is an extract from the Consolidated Database System (CDBS) licensed by the Media Bureau. It consists of Analog Television Stations (see Rule Part47 CFR...

  5. Analog multivariate counting analyzers

    CERN Document Server

    Nikitin, A V; Armstrong, T P

    2003-01-01

    Characterizing rates of occurrence of various features of a signal is of great importance in numerous types of physical measurements. Such signal features can be defined as certain discrete coincidence events, e.g. crossings of a signal with a given threshold, or occurrence of extrema of a certain amplitude. We describe measuring rates of such events by means of analog multivariate counting analyzers. Given a continuous scalar or multicomponent (vector) input signal, an analog counting analyzer outputs a continuous signal with the instantaneous magnitude equal to the rate of occurrence of certain coincidence events. The analog nature of the proposed analyzers allows us to reformulate many problems of the traditional counting measurements, and cast them in a form which is readily addressed by methods of differential calculus rather than by algebraic or logical means of digital signal processing. Analog counting analyzers can be easily implemented in discrete or integrated electronic circuits, do not suffer fro...

  6. Challenges in Analogical Reasoning

    CERN Document Server

    Lin, Shih-Yin

    2016-01-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same physics principle is involved but that is more difficult to handle. Here, we examine introductory physics students' ability to use analogies in solving problems involving Newton's second law. Students enrolled in an algebra-based introductory physics course were given a solved problem involving tension in a rope and were then asked to solve another problem for which the physics is very similar but involved a frictional force. They were asked to point out the similarities between the two problems and then use the analogy to solve the friction problem.

  7. Synthesis of Paclitaxel Analogs

    OpenAIRE

    Xu, Zhibing

    2010-01-01

    Paclitaxel is one of the most successful anti-cancer drugs, particularly in the treatment of breast cancer and ovarian cancer. For the investigation of the interaction between paclitaxel and MD-2 protein, and development of new antagonists for lipopolysaccharide, several C10 A-nor-paclitaxel analogs have been synthesized and their biological activities have been evaluated. In order to reduce the myelosuppression effect of the paclitaxel, several C3â ² and C4 paclitaxel analogs have been synth...

  8. FGF growth factor analogs

    Science.gov (United States)

    Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY; Takahashi, Kazuyuki [Germantown, MD

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  9. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  10. Electrical Circuits and Water Analogies

    Science.gov (United States)

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  11. Generating Analog IC Layouts with LAYGEN II

    CERN Document Server

    Martins, Ricardo M F; Horta, Nuno C G

    2013-01-01

    This book presents an innovative methodology for the automatic generation of analog integrated circuits (ICs) layout, based on template descriptions and on evolutionary computational techniques. A design automation tool, LAYGEN II, was implemented to validate the proposed approach giving special emphasis to reusability of expert design knowledge and to efficiency on retargeting operations.

  12. Digital and analog communication systems

    Science.gov (United States)

    Shanmugam, K. S.

    1979-01-01

    The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

  13. Analogical Reasoning in Geometry Education

    Science.gov (United States)

    Magdas, Ioana

    2015-01-01

    The analogical reasoning isn't used only in mathematics but also in everyday life. In this article we approach the analogical reasoning in Geometry Education. The novelty of this article is a classification of geometrical analogies by reasoning type and their exemplification. Our classification includes: analogies for understanding and setting a…

  14. A Computer-Based Visual Analog Scale,

    Science.gov (United States)

    1992-06-01

    Methamphetamine, Ephedrine , Phenmetrazine, and methylphenidate in Man." Clinical Pharmacology and Therapeutics, Vol. 12, pp. 245-258, 1971. 11...8217. SYMPTOM.EXE reads the input path’s directory, looking for matches to the file-specification. If it finds no matches, it will abort with a message. Otherwise

  15. COMPUTER CONTROL OF AN ANALOG VOCAL TRACT

    Science.gov (United States)

    electrically controlled by a nasal coupling signal, and represent the action of the velum . The remaining sections are fixed as they do not vary significantly during the production of speech sounds. (Author)

  16. COMPUTING

    CERN Multimedia

    M. Kasemann

    Overview In autumn the main focus was to process and handle CRAFT data and to perform the Summer08 MC production. The operational aspects were well covered by regular Computing Shifts, experts on duty and Computing Run Coordination. At the Computing Resource Board (CRB) in October a model to account for service work at Tier 2s was approved. The computing resources for 2009 were reviewed for presentation at the C-RRB. The quarterly resource monitoring is continuing. Facilities/Infrastructure operations Operations during CRAFT data taking ran fine. This proved to be a very valuable experience for T0 workflows and operations. The transfers of custodial data to most T1s went smoothly. A first round of reprocessing started at the Tier-1 centers end of November; it will take about two weeks. The Computing Shifts procedure was tested full scale during this period and proved to be very efficient: 30 Computing Shifts Persons (CSP) and 10 Computing Resources Coordinators (CRC). The shift program for the shut down w...

  17. Implementing neural architectures using analog VLSI circuits

    Science.gov (United States)

    Maher, Mary Ann C.; Deweerth, Stephen P.; Mahowald, Misha A.; Mead, Carver A.

    1989-05-01

    Analog very large-scale integrated (VLSI) technology can be used not only to study and simulate biological systems, but also to emulate them in designing artificial sensory systems. A methodology for building these systems in CMOS VLSI technology has been developed using analog micropower circuit elements that can be hierarchically combined. Using this methodology, experimental VLSI chips of visual and motor subsystems have been designed and fabricated. These chips exhibit behavior similar to that of biological systems, and perform computations useful for artificial sensory systems.

  18. HAPS, a Handy Analog Programming System

    DEFF Research Database (Denmark)

    Højberg, Kristian Søe

    1975-01-01

    HAPS (Hybrid Analog Programming System) is an analog compiler that can be run on a minicomputer in an interactive mode. Essentially HAPS is written in FORTRAN. The equations to be programmed for an ana log computer are read in by using a FORTRAN-like notation. The input must contain maximum...... and minimum values for the variables. The output file includes potentiometer coefficients and static-test 'measuring values.' The file format is fitted to an automatic potentiometer-setting and static-test program. Patch instructions are printed by HAPS. The article describes the principles of HAPS...

  19. Associative Pattern Recognition In Analog VLSI Circuits

    Science.gov (United States)

    Tawel, Raoul

    1995-01-01

    Winner-take-all circuit selects best-match stored pattern. Prototype cascadable very-large-scale integrated (VLSI) circuit chips built and tested to demonstrate concept of electronic associative pattern recognition. Based on low-power, sub-threshold analog complementary oxide/semiconductor (CMOS) VLSI circuitry, each chip can store 128 sets (vectors) of 16 analog values (vector components), vectors representing known patterns as diverse as spectra, histograms, graphs, or brightnesses of pixels in images. Chips exploit parallel nature of vector quantization architecture to implement highly parallel processing in relatively simple computational cells. Through collective action, cells classify input pattern in fraction of microsecond while consuming power of few microwatts.

  20. Analogy, explanation, and proof.

    Science.gov (United States)

    Hummel, John E; Licato, John; Bringsjord, Selmer

    2014-01-01

    People are habitual explanation generators. At its most mundane, our propensity to explain allows us to infer that we should not drink milk that smells sour; at the other extreme, it allows us to establish facts (e.g., theorems in mathematical logic) whose truth was not even known prior to the existence of the explanation (proof). What do the cognitive operations underlying the inference that the milk is sour have in common with the proof that, say, the square root of two is irrational? Our ability to generate explanations bears striking similarities to our ability to make analogies. Both reflect a capacity to generate inferences and generalizations that go beyond the featural similarities between a novel problem and familiar problems in terms of which the novel problem may be understood. However, a notable difference between analogy-making and explanation-generation is that the former is a process in which a single source situation is used to reason about a single target, whereas the latter often requires the reasoner to integrate multiple sources of knowledge. This seemingly small difference poses a challenge to the task of marshaling our understanding of analogical reasoning to understanding explanation. We describe a model of explanation, derived from a model of analogy, adapted to permit systematic violations of this one-to-one mapping constraint. Simulation results demonstrate that the resulting model can generate explanations for novel explananda and that, like the explanations generated by human reasoners, these explanations vary in their coherence.

  1. Are Scientific Analogies Metaphors?

    Science.gov (United States)

    1981-02-01

    psychospiritual processes. A more modern example of unclarified analogy is Freud’s (1973; reprinted from 1955) discussion of anal- eroticism , in which...299-304. Freud, S. On transformations of instinct as exemplified in anal eroticism . In J. Strachey (Ed.), The standard 37 edition of the complete

  2. Analog versus digital: extrapolating from electronics to neurobiology.

    Science.gov (United States)

    Sarpeshkar, R

    1998-10-01

    We review the pros and cons of analog and digital computation. We propose that computation that is most efficient in its use of resources is neither analog computation nor digital computation but, rather, a mixture of the two forms. For maximum efficiency, the information and information-processing resources of the hybrid form must be distributed over many wires, with an optimal signal-to-noise ratio per wire. Our results suggest that it is likely that the brain computes in a hybrid fashion and that an underappreciated and important reason for the efficiency of the human brain, which consumes only 12 W, is the hybrid and distributed nature of its architecture.

  3. COMPUTING

    CERN Multimedia

    M. Kasemann

    Overview During the past three months activities were focused on data operations, testing and re-enforcing shift and operational procedures for data production and transfer, MC production and on user support. Planning of the computing resources in view of the new LHC calendar in ongoing. Two new task forces were created for supporting the integration work: Site Commissioning, which develops tools helping distributed sites to monitor job and data workflows, and Analysis Support, collecting the user experience and feedback during analysis activities and developing tools to increase efficiency. The development plan for DMWM for 2009/2011 was developed at the beginning of the year, based on the requirements from the Physics, Computing and Offline groups (see Offline section). The Computing management meeting at FermiLab on February 19th and 20th was an excellent opportunity discussing the impact and for addressing issues and solutions to the main challenges facing CMS computing. The lack of manpower is particul...

  4. COMPUTING

    CERN Multimedia

    I. Fisk

    2011-01-01

    Introduction CMS distributed computing system performed well during the 2011 start-up. The events in 2011 have more pile-up and are more complex than last year; this results in longer reconstruction times and harder events to simulate. Significant increases in computing capacity were delivered in April for all computing tiers, and the utilisation and load is close to the planning predictions. All computing centre tiers performed their expected functionalities. Heavy-Ion Programme The CMS Heavy-Ion Programme had a very strong showing at the Quark Matter conference. A large number of analyses were shown. The dedicated heavy-ion reconstruction facility at the Vanderbilt Tier-2 is still involved in some commissioning activities, but is available for processing and analysis. Facilities and Infrastructure Operations Facility and Infrastructure operations have been active with operations and several important deployment tasks. Facilities participated in the testing and deployment of WMAgent and WorkQueue+Request...

  5. COMPUTING

    CERN Multimedia

    P. McBride

    The Computing Project is preparing for a busy year where the primary emphasis of the project moves towards steady operations. Following the very successful completion of Computing Software and Analysis challenge, CSA06, last fall, we have reorganized and established four groups in computing area: Commissioning, User Support, Facility/Infrastructure Operations and Data Operations. These groups work closely together with groups from the Offline Project in planning for data processing and operations. Monte Carlo production has continued since CSA06, with about 30M events produced each month to be used for HLT studies and physics validation. Monte Carlo production will continue throughout the year in the preparation of large samples for physics and detector studies ramping to 50 M events/month for CSA07. Commissioning of the full CMS computing system is a major goal for 2007. Site monitoring is an important commissioning component and work is ongoing to devise CMS specific tests to be included in Service Availa...

  6. The production of body analogs for use in radiation physics.

    Science.gov (United States)

    Metcalfe, P E; Hoban, P W; Harper, N R; Murray, D C; Round, W H

    1990-09-01

    Bone, muscle and lung analog materials have been produced in-house, and dosimetry phantoms have been produced. A method using computed tomography (CT) has been developed to check that the analogs produced match the radiation properties of body tissues. The relative electron densities and ratio of electron cross sections are calculated from elemental compositions of the analogs. Using these data the theoretical CT numbers are calculated and these numbers are compared with experimental CT numbers for the analogs produced. The experimental CT numbers are found by scanning the samples on a Siemens DRH CT scanner. Results show the maximum difference between theoretical and experimental CT numbers for the analogs is 18 Hounsfield units, which relates to a delta NCT of less than 1%. Comparison of analog CT numbers with CT numbers for the related patient tissues also shows a close match.

  7. COMPUTING

    CERN Multimedia

    I. Fisk

    2013-01-01

    Computing activity had ramped down after the completion of the reprocessing of the 2012 data and parked data, but is increasing with new simulation samples for analysis and upgrade studies. Much of the Computing effort is currently involved in activities to improve the computing system in preparation for 2015. Operations Office Since the beginning of 2013, the Computing Operations team successfully re-processed the 2012 data in record time, not only by using opportunistic resources like the San Diego Supercomputer Center which was accessible, to re-process the primary datasets HTMHT and MultiJet in Run2012D much earlier than planned. The Heavy-Ion data-taking period was successfully concluded in February collecting almost 500 T. Figure 3: Number of events per month (data) In LS1, our emphasis is to increase efficiency and flexibility of the infrastructure and operation. Computing Operations is working on separating disk and tape at the Tier-1 sites and the full implementation of the xrootd federation ...

  8. Synthetic Biology: A Unifying View and Review Using Analog Circuits.

    Science.gov (United States)

    Teo, Jonathan J Y; Woo, Sung Sik; Sarpeshkar, Rahul

    2015-08-01

    We review the field of synthetic biology from an analog circuits and analog computation perspective, focusing on circuits that have been built in living cells. This perspective is well suited to pictorially, symbolically, and quantitatively representing the nonlinear, dynamic, and stochastic (noisy) ordinary and partial differential equations that rigorously describe the molecular circuits of synthetic biology. This perspective enables us to construct a canonical analog circuit schematic that helps unify and review the operation of many fundamental circuits that have been built in synthetic biology at the DNA, RNA, protein, and small-molecule levels over nearly two decades. We review 17 circuits in the literature as particular examples of feedforward and feedback analog circuits that arise from special topological cases of the canonical analog circuit schematic. Digital circuit operation of these circuits represents a special case of saturated analog circuit behavior and is automatically incorporated as well. Many issues that have prevented synthetic biology from scaling are naturally represented in analog circuit schematics. Furthermore, the deep similarity between the Boltzmann thermodynamic equations that describe noisy electronic current flow in subthreshold transistors and noisy molecular flux in biochemical reactions has helped map analog circuit motifs in electronics to analog circuit motifs in cells and vice versa via a `cytomorphic' approach. Thus, a body of knowledge in analog electronic circuit design, analysis, simulation, and implementation may also be useful in the robust and efficient design of molecular circuits in synthetic biology, helping it to scale to more complex circuits in the future.

  9. Computer

    CERN Document Server

    Atkinson, Paul

    2011-01-01

    The pixelated rectangle we spend most of our day staring at in silence is not the television as many long feared, but the computer-the ubiquitous portal of work and personal lives. At this point, the computer is almost so common we don't notice it in our view. It's difficult to envision that not that long ago it was a gigantic, room-sized structure only to be accessed by a few inspiring as much awe and respect as fear and mystery. Now that the machine has decreased in size and increased in popular use, the computer has become a prosaic appliance, little-more noted than a toaster. These dramati

  10. Terrestrial Spaceflight Analogs: Antarctica

    Science.gov (United States)

    Crucian, Brian

    2013-01-01

    Alterations in immune cell distribution and function, circadian misalignment, stress and latent viral reactivation appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Others are unique to the Concordia analog. Based on some initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune system changes and mission stress effects. An ongoing smaller control study at Neumayer III will address the influence of the hypoxic variable. Changes were observed in the peripheral blood leukocyte distribution consistent with immune mobilization, and similar to those observed during spaceflight. Alterations in cytokine production profiles were observed during winterover that are distinct from those observed during spaceflight, but potentially consistent with those observed during persistent hypobaric hypoxia. The reactivation of latent herpesviruses was observed during overwinter/isolation, that is consistently associated with dysregulation in immune function.

  11. Analogy, Explanation, and Proof

    Directory of Open Access Journals (Sweden)

    John eHummel

    2014-11-01

    Full Text Available People are habitual explanation generators. At its most mundane, our propensity to explain allows us to infer that we should not drink milk that smells sour; at the other extreme, it allows us to establish facts (e.g., theorems in mathematical logic whose truth was not even known prior to the existence of the explanation (proof. What do the cognitive operations underlying the (inductive inference that the milk is sour have in common with the (deductive proof that, say, the square root of two is irrational? Our ability to generate explanations bears striking similarities to our ability to make analogies. Both reflect a capacity to generate inferences and generalizations that go beyond the featural similarities between a novel problem and familiar problems in terms of which the novel problem may be understood. However, a notable difference between analogy-making and explanation-generation is that the former is a process in which a single source situation is used to reason about a single target, whereas the latter often requires the reasoner to integrate multiple sources of knowledge. This small-seeming difference poses a challenge to the task of marshaling our understanding of analogical reasoning in the service of understanding explanation. We describe a model of explanation, derived from a model of analogy, adapted to permit systematic violations of this one-to-one mapping constraint. Simulation results demonstrate that the resulting model can generate explanations for novel explananda and that, like the explanations generated by human reasoners, these explanations vary in their coherence.

  12. A Transiting Jupiter Analog

    CERN Document Server

    Kipping, David M; Henze, Chris; Teachey, Alex; Isaacson, Howard T; Petigura, Erik A; Marcy, Geoffrey W; Buchhave, Lars A; Chen, Jingjing; Bryson, Steve T; Sandford, Emily

    2016-01-01

    Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. Despite the great successes of recent transit surveys, Jupiter analogs represent a terra incognita, owing to the strong intrinsic bias of this method against long orbital periods. We here report on the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02), discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945. With a radius of $(0.91\\pm0.02)$ $R_{\\mathrm{Jup}}$, a low orbital eccentricity ($0.06_{-0.04}^{+0.10}$) and an equilibrium temperature of $(131\\pm3)$ K, Kepler-167e bears many of the basic hallmarks of Jupiter. Kepler-167e is accompanied by three Super-Earths on compact orbits, which we also validate, leaving a large cavity of transiting worlds around the habitable-zone. With two transits and continuous photometric ...

  13. COMPUTING

    CERN Document Server

    I. Fisk

    2010-01-01

    Introduction It has been a very active quarter in Computing with interesting progress in all areas. The activity level at the computing facilities, driven by both organised processing from data operations and user analysis, has been steadily increasing. The large-scale production of simulated events that has been progressing throughout the fall is wrapping-up and reprocessing with pile-up will continue. A large reprocessing of all the proton-proton data has just been released and another will follow shortly. The number of analysis jobs by users each day, that was already hitting the computing model expectations at the time of ICHEP, is now 33% higher. We are expecting a busy holiday break to ensure samples are ready in time for the winter conferences. Heavy Ion An activity that is still in progress is computing for the heavy-ion program. The heavy-ion events are collected without zero suppression, so the event size is much large at roughly 11 MB per event of RAW. The central collisions are more complex and...

  14. COMPUTING

    CERN Multimedia

    M. Kasemann P. McBride Edited by M-C. Sawley with contributions from: P. Kreuzer D. Bonacorsi S. Belforte F. Wuerthwein L. Bauerdick K. Lassila-Perini M-C. Sawley

    Introduction More than seventy CMS collaborators attended the Computing and Offline Workshop in San Diego, California, April 20-24th to discuss the state of readiness of software and computing for collisions. Focus and priority were given to preparations for data taking and providing room for ample dialog between groups involved in Commissioning, Data Operations, Analysis and MC Production. Throughout the workshop, aspects of software, operating procedures and issues addressing all parts of the computing model were discussed. Plans for the CMS participation in STEP’09, the combined scale testing for all four experiments due in June 2009, were refined. The article in CMS Times by Frank Wuerthwein gave a good recap of the highly collaborative atmosphere of the workshop. Many thanks to UCSD and to the organizers for taking care of this workshop, which resulted in a long list of action items and was definitely a success. A considerable amount of effort and care is invested in the estimate of the comput...

  15. Inductive, Analogical, and Communicative Generalization

    Directory of Open Access Journals (Sweden)

    Adri Smaling

    2003-03-01

    Full Text Available Three forms of inductive generalization - statistical generalization, variation-based generalization and theory-carried generalization - are insufficient concerning case-to-case generalization, which is a form of analogical generalization. The quality of case-to-case generalization needs to be reinforced by setting up explicit analogical argumentation. To evaluate analogical argumentation six criteria are discussed. Good analogical reasoning is an indispensable support to forms of communicative generalization - receptive and responsive (participative generalization — as well as exemplary generalization.

  16. COMPUTING

    CERN Multimedia

    I. Fisk

    2011-01-01

    Introduction It has been a very active quarter in Computing with interesting progress in all areas. The activity level at the computing facilities, driven by both organised processing from data operations and user analysis, has been steadily increasing. The large-scale production of simulated events that has been progressing throughout the fall is wrapping-up and reprocessing with pile-up will continue. A large reprocessing of all the proton-proton data has just been released and another will follow shortly. The number of analysis jobs by users each day, that was already hitting the computing model expectations at the time of ICHEP, is now 33% higher. We are expecting a busy holiday break to ensure samples are ready in time for the winter conferences. Heavy Ion The Tier 0 infrastructure was able to repack and promptly reconstruct heavy-ion collision data. Two copies were made of the data at CERN using a large CASTOR disk pool, and the core physics sample was replicated ...

  17. COMPUTING

    CERN Multimedia

    M. Kasemann

    Introduction More than seventy CMS collaborators attended the Computing and Offline Workshop in San Diego, California, April 20-24th to discuss the state of readiness of software and computing for collisions. Focus and priority were given to preparations for data taking and providing room for ample dialog between groups involved in Commissioning, Data Operations, Analysis and MC Production. Throughout the workshop, aspects of software, operating procedures and issues addressing all parts of the computing model were discussed. Plans for the CMS participation in STEP’09, the combined scale testing for all four experiments due in June 2009, were refined. The article in CMS Times by Frank Wuerthwein gave a good recap of the highly collaborative atmosphere of the workshop. Many thanks to UCSD and to the organizers for taking care of this workshop, which resulted in a long list of action items and was definitely a success. A considerable amount of effort and care is invested in the estimate of the co...

  18. COMPUTING

    CERN Multimedia

    I. Fisk

    2012-01-01

    Introduction Computing continued with a high level of activity over the winter in preparation for conferences and the start of the 2012 run. 2012 brings new challenges with a new energy, more complex events, and the need to make the best use of the available time before the Long Shutdown. We expect to be resource constrained on all tiers of the computing system in 2012 and are working to ensure the high-priority goals of CMS are not impacted. Heavy ions After a successful 2011 heavy-ion run, the programme is moving to analysis. During the run, the CAF resources were well used for prompt analysis. Since then in 2012 on average 200 job slots have been used continuously at Vanderbilt for analysis workflows. Operations Office As of 2012, the Computing Project emphasis has moved from commissioning to operation of the various systems. This is reflected in the new organisation structure where the Facilities and Data Operations tasks have been merged into a common Operations Office, which now covers everything ...

  19. COMPUTING

    CERN Multimedia

    M. Kasemann

    Introduction During the past six months, Computing participated in the STEP09 exercise, had a major involvement in the October exercise and has been working with CMS sites on improving open issues relevant for data taking. At the same time operations for MC production, real data reconstruction and re-reconstructions and data transfers at large scales were performed. STEP09 was successfully conducted in June as a joint exercise with ATLAS and the other experiments. It gave good indication about the readiness of the WLCG infrastructure with the two major LHC experiments stressing the reading, writing and processing of physics data. The October Exercise, in contrast, was conducted as an all-CMS exercise, where Physics, Computing and Offline worked on a common plan to exercise all steps to efficiently access and analyze data. As one of the major results, the CMS Tier-2s demonstrated to be fully capable for performing data analysis. In recent weeks, efforts were devoted to CMS Computing readiness. All th...

  20. COMPUTING

    CERN Multimedia

    P. McBride

    It has been a very active year for the computing project with strong contributions from members of the global community. The project has focused on site preparation and Monte Carlo production. The operations group has begun processing data from P5 as part of the global data commissioning. Improvements in transfer rates and site availability have been seen as computing sites across the globe prepare for large scale production and analysis as part of CSA07. Preparations for the upcoming Computing Software and Analysis Challenge CSA07 are progressing. Ian Fisk and Neil Geddes have been appointed as coordinators for the challenge. CSA07 will include production tests of the Tier-0 production system, reprocessing at the Tier-1 sites and Monte Carlo production at the Tier-2 sites. At the same time there will be a large analysis exercise at the Tier-2 centres. Pre-production simulation of the Monte Carlo events for the challenge is beginning. Scale tests of the Tier-0 will begin in mid-July and the challenge it...

  1. COMPUTING

    CERN Multimedia

    I. Fisk

    2010-01-01

    Introduction The first data taking period of November produced a first scientific paper, and this is a very satisfactory step for Computing. It also gave the invaluable opportunity to learn and debrief from this first, intense period, and make the necessary adaptations. The alarm procedures between different groups (DAQ, Physics, T0 processing, Alignment/calibration, T1 and T2 communications) have been reinforced. A major effort has also been invested into remodeling and optimizing operator tasks in all activities in Computing, in parallel with the recruitment of new Cat A operators. The teams are being completed and by mid year the new tasks will have been assigned. CRB (Computing Resource Board) The Board met twice since last CMS week. In December it reviewed the experience of the November data-taking period and could measure the positive improvements made for the site readiness. It also reviewed the policy under which Tier-2 are associated with Physics Groups. Such associations are decided twice per ye...

  2. COMPUTING

    CERN Multimedia

    M. Kasemann

    CCRC’08 challenges and CSA08 During the February campaign of the Common Computing readiness challenges (CCRC’08), the CMS computing team had achieved very good results. The link between the detector site and the Tier0 was tested by gradually increasing the number of parallel transfer streams well beyond the target. Tests covered the global robustness at the Tier0, processing a massive number of very large files and with a high writing speed to tapes.  Other tests covered the links between the different Tiers of the distributed infrastructure and the pre-staging and reprocessing capacity of the Tier1’s: response time, data transfer rate and success rate for Tape to Buffer staging of files kept exclusively on Tape were measured. In all cases, coordination with the sites was efficient and no serious problem was found. These successful preparations prepared the ground for the second phase of the CCRC’08 campaign, in May. The Computing Software and Analysis challen...

  3. ESD analog circuits and design

    CERN Document Server

    Voldman, Steven H

    2014-01-01

    A comprehensive and in-depth review of analog circuit layout, schematic architecture, device, power network and ESD design This book will provide a balanced overview of analog circuit design layout, analog circuit schematic development, architecture of chips, and ESD design.  It will start at an introductory level and will bring the reader right up to the state-of-the-art. Two critical design aspects for analog and power integrated circuits are combined. The first design aspect covers analog circuit design techniques to achieve the desired circuit performance. The second and main aspect pres

  4. COMPUTING

    CERN Multimedia

    I. Fisk

    2013-01-01

    Computing operation has been lower as the Run 1 samples are completing and smaller samples for upgrades and preparations are ramping up. Much of the computing activity is focusing on preparations for Run 2 and improvements in data access and flexibility of using resources. Operations Office Data processing was slow in the second half of 2013 with only the legacy re-reconstruction pass of 2011 data being processed at the sites.   Figure 1: MC production and processing was more in demand with a peak of over 750 Million GEN-SIM events in a single month.   Figure 2: The transfer system worked reliably and efficiently and transferred on average close to 520 TB per week with peaks at close to 1.2 PB.   Figure 3: The volume of data moved between CMS sites in the last six months   The tape utilisation was a focus for the operation teams with frequent deletion campaigns from deprecated 7 TeV MC GEN-SIM samples to INVALID datasets, which could be cleaned up...

  5. COMPUTING

    CERN Document Server

    I. Fisk

    2012-01-01

      Introduction Computing activity has been running at a sustained, high rate as we collect data at high luminosity, process simulation, and begin to process the parked data. The system is functional, though a number of improvements are planned during LS1. Many of the changes will impact users, we hope only in positive ways. We are trying to improve the distributed analysis tools as well as the ability to access more data samples more transparently.  Operations Office Figure 2: Number of events per month, for 2012 Since the June CMS Week, Computing Operations teams successfully completed data re-reconstruction passes and finished the CMSSW_53X MC campaign with over three billion events available in AOD format. Recorded data was successfully processed in parallel, exceeding 1.2 billion raw physics events per month for the first time in October 2012 due to the increase in data-parking rate. In parallel, large efforts were dedicated to WMAgent development and integrati...

  6. COMPUTING

    CERN Multimedia

    Matthias Kasemann

    Overview The main focus during the summer was to handle data coming from the detector and to perform Monte Carlo production. The lessons learned during the CCRC and CSA08 challenges in May were addressed by dedicated PADA campaigns lead by the Integration team. Big improvements were achieved in the stability and reliability of the CMS Tier1 and Tier2 centres by regular and systematic follow-up of faults and errors with the help of the Savannah bug tracking system. In preparation for data taking the roles of a Computing Run Coordinator and regular computing shifts monitoring the services and infrastructure as well as interfacing to the data operations tasks are being defined. The shift plan until the end of 2008 is being put together. User support worked on documentation and organized several training sessions. The ECoM task force delivered the report on “Use Cases for Start-up of pp Data-Taking” with recommendations and a set of tests to be performed for trigger rates much higher than the ...

  7. COMPUTING

    CERN Multimedia

    M. Kasemann

    Introduction A large fraction of the effort was focused during the last period into the preparation and monitoring of the February tests of Common VO Computing Readiness Challenge 08. CCRC08 is being run by the WLCG collaboration in two phases, between the centres and all experiments. The February test is dedicated to functionality tests, while the May challenge will consist of running at all centres and with full workflows. For this first period, a number of functionality checks of the computing power, data repositories and archives as well as network links are planned. This will help assess the reliability of the systems under a variety of loads, and identifying possible bottlenecks. Many tests are scheduled together with other VOs, allowing the full scale stress test. The data rates (writing, accessing and transfer¬ring) are being checked under a variety of loads and operating conditions, as well as the reliability and transfer rates of the links between Tier-0 and Tier-1s. In addition, the capa...

  8. COMPUTING

    CERN Multimedia

    Contributions from I. Fisk

    2012-01-01

    Introduction The start of the 2012 run has been busy for Computing. We have reconstructed, archived, and served a larger sample of new data than in 2011, and we are in the process of producing an even larger new sample of simulations at 8 TeV. The running conditions and system performance are largely what was anticipated in the plan, thanks to the hard work and preparation of many people. Heavy ions Heavy Ions has been actively analysing data and preparing for conferences.  Operations Office Figure 6: Transfers from all sites in the last 90 days For ICHEP and the Upgrade efforts, we needed to produce and process record amounts of MC samples while supporting the very successful data-taking. This was a large burden, especially on the team members. Nevertheless the last three months were very successful and the total output was phenomenal, thanks to our dedicated site admins who keep the sites operational and the computing project members who spend countless hours nursing the...

  9. COMPUTING

    CERN Multimedia

    P. MacBride

    The Computing Software and Analysis Challenge CSA07 has been the main focus of the Computing Project for the past few months. Activities began over the summer with the preparation of the Monte Carlo data sets for the challenge and tests of the new production system at the Tier-0 at CERN. The pre-challenge Monte Carlo production was done in several steps: physics generation, detector simulation, digitization, conversion to RAW format and the samples were run through the High Level Trigger (HLT). The data was then merged into three "Soups": Chowder (ALPGEN), Stew (Filtered Pythia) and Gumbo (Pythia). The challenge officially started when the first Chowder events were reconstructed on the Tier-0 on October 3rd. The data operations teams were very busy during the the challenge period. The MC production teams continued with signal production and processing while the Tier-0 and Tier-1 teams worked on splitting the Soups into Primary Data Sets (PDS), reconstruction and skimming. The storage sys...

  10. COMPUTING

    CERN Multimedia

    2010-01-01

    Introduction Just two months after the “LHC First Physics” event of 30th March, the analysis of the O(200) million 7 TeV collision events in CMS accumulated during the first 60 days is well under way. The consistency of the CMS computing model has been confirmed during these first weeks of data taking. This model is based on a hierarchy of use-cases deployed between the different tiers and, in particular, the distribution of RECO data to T1s, who then serve data on request to T2s, along a topology known as “fat tree”. Indeed, during this period this model was further extended by almost full “mesh” commissioning, meaning that RECO data were shipped to T2s whenever possible, enabling additional physics analyses compared with the “fat tree” model. Computing activities at the CMS Analysis Facility (CAF) have been marked by a good time response for a load almost evenly shared between ALCA (Alignment and Calibration tasks - highest p...

  11. Albert Einstein, Analogizer Extraordinaire

    CERN Document Server

    CERN. Geneva

    2007-01-01

    Where does deep insight in physics come from? It is tempting to think that it comes from the purest and most precise of reasoning, following ironclad laws of thought that compel the clear mind completely rigidly. And yet the truth is quite otherwise. One finds, when one looks closely at any major discovery, that the greatest of physicists are, in some sense, the most crazily daring and irrational of all physicists. Albert Einstein exemplifies this thesis in spades. In this talk I will describe the key role, throughout Albert Einstein's fabulously creative life, played by wild guesses made by analogy lacking any basis whatsoever in pure reasoning. In particular, in this year of 2007, the centenary of 1907, I will describe how over the course of two years (1905 through 1907) of pondering, Einstein slowly came, via analogy, to understand the full, radical consequences of the equation that he had first discovered and published in 1905, arguably the most famous equation of all time: E = mc2.

  12. COMPUTING

    CERN Multimedia

    I. Fisk

    2011-01-01

    Introduction The Computing Team successfully completed the storage, initial processing, and distribution for analysis of proton-proton data in 2011. There are still a variety of activities ongoing to support winter conference activities and preparations for 2012. Heavy ions The heavy-ion run for 2011 started in early November and has already demonstrated good machine performance and success of some of the more advanced workflows planned for 2011. Data collection will continue until early December. Facilities and Infrastructure Operations Operational and deployment support for WMAgent and WorkQueue+Request Manager components, routinely used in production by Data Operations, are provided. The GlideInWMS and components installation are now deployed at CERN, which is added to the GlideInWMS factory placed in the US. There has been new operational collaboration between the CERN team and the UCSD GlideIn factory operators, covering each others time zones by monitoring/debugging pilot jobs sent from the facto...

  13. Vorticity in analog gravity

    Science.gov (United States)

    Cropp, Bethan; Liberati, Stefano; Turcati, Rodrigo

    2016-06-01

    In the analog gravity framework, the acoustic disturbances in a moving fluid can be described by an equation of motion identical to a relativistic scalar massless field propagating in curved space-time. This description is possible only when the fluid under consideration is barotropic, inviscid, and irrotational. In this case, the propagation of the perturbations is governed by an acoustic metric that depends algebrically on the local speed of sound, density, and the background flow velocity, the latter assumed to be vorticity-free. In this work we provide a straightforward extension in order to go beyond the irrotational constraint. Using a charged—relativistic and nonrelativistic—Bose-Einstein condensate as a physical system, we show that in the low-momentum limit and performing the eikonal approximation we can derive a d’Alembertian equation of motion for the charged phonons where the emergent acoustic metric depends on flow velocity in the presence of vorticity.

  14. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  15. COMPUTING

    CERN Multimedia

    M. Kasemann

    CMS relies on a well functioning, distributed computing infrastructure. The Site Availability Monitoring (SAM) and the Job Robot submission have been very instrumental for site commissioning in order to increase availability of more sites such that they are available to participate in CSA07 and are ready to be used for analysis. The commissioning process has been further developed, including "lessons learned" documentation via the CMS twiki. Recently the visualization, presentation and summarizing of SAM tests for sites has been redesigned, it is now developed by the central ARDA project of WLCG. Work to test the new gLite Workload Management System was performed; a 4 times increase in throughput with respect to LCG Resource Broker is observed. CMS has designed and launched a new-generation traffic load generator called "LoadTest" to commission and to keep exercised all data transfer routes in the CMS PhE-DEx topology. Since mid-February, a transfer volume of about 12 P...

  16. Neural Computation and the Computational Theory of Cognition

    Science.gov (United States)

    Piccinini, Gualtiero; Bahar, Sonya

    2013-01-01

    We begin by distinguishing computationalism from a number of other theses that are sometimes conflated with it. We also distinguish between several important kinds of computation: computation in a generic sense, digital computation, and analog computation. Then, we defend a weak version of computationalism--neural processes are computations in the…

  17. Beginning analog electronics through projects

    CERN Document Server

    Singmin, Andrew

    2001-01-01

    Analog electronics is the simplest way to start a fun, informative, learning program. Beginning Analog Electronics Through Projects, Second Edition was written with the needs of beginning hobbyists and students in mind. This revision of Andrew Singmin's popular Beginning Electronics Through Projects provides practical exercises, building techniques, and ideas for useful electronics projects. Additionally, it features new material on analog and digital electronics, and new projects for troubleshooting test equipment.Published in the tradition of Beginning Electronics Through Projects an

  18. Mathematical problem solving by analogy.

    Science.gov (United States)

    Novick, L R; Holyoak, K J

    1991-05-01

    We report the results of 2 experiments and a verbal protocol study examining the component processes of solving mathematical word problems by analogy. College students first studied a problem and its solution, which provided a potential source for analogical transfer. Then they attempted to solve several analogous problems. For some problems, subjects received one of a variety of hints designed to reduce or eliminate the difficulty of some of the major processes hypothesized to be involved in analogical transfer. Our studies yielded 4 major findings. First, the process of mapping the features of the source and target problems and the process of adapting the source solution procedure for use in solving the target problem were clearly distinguished: (a) Successful mapping was found to be insufficient for successful transfer and (b) adaptation was found to be a major source of transfer difficulty. Second, we obtained direct evidence that schema induction is a natural consequence of analogical transfer. The schema was found to co-exist with the problems from which it was induced, and both the schema and the individual problems facilitated later transfer. Third, for our multiple-solution problems, the relation between analogical transfer and solution accuracy was mediated by the degree of time pressure exerted for the test problems. Finally, mathematical expertise was a significant predictor of analogical transfer, but general analogical reasoning ability was not. The implications of the results for models of analogical transfer and for instruction were considered.

  19. A radial basis function neurocomputer implemented with analog VLSI circuits

    Science.gov (United States)

    Watkins, Steven S.; Chau, Paul M.; Tawel, Raoul

    1992-01-01

    An electronic neurocomputer which implements a radial basis function neural network (RBFNN) is described. The RBFNN is a network that utilizes a radial basis function as the transfer function. The key advantages of RBFNNs over existing neural network architectures include reduced learning time and the ease of VLSI implementation. This neurocomputer is based on an analog/digital hybrid design and has been constructed with both custom analog VLSI circuits and a commercially available digital signal processor. The hybrid architecture is selected because it offers high computational performance while compensating for analog inaccuracies, and it features the ability to model large problems.

  20. [Analogies and analogy research in technical biology and bionics].

    Science.gov (United States)

    Nachtigall, Werner

    2010-01-01

    The procedural approaches of Technical Biology and Bionics are characterized, and analogy research is identified as their common basis. The actual creative aspect in bionical research lies in recognizing and exploiting technically oriented analogies underlying a specific biological prototype to indicate a specific technical application.

  1. A new program on digitizing analog seismograms

    Science.gov (United States)

    Wang, Maofa; Jiang, Qigang; Liu, Qingjie; Huang, Meng

    2016-08-01

    Historical seismograms contain a great variety of useful information which can be used in the study of earthquakes. It is necessary for researchers to digitize analog records and extract the information just as modern computing analysis requires. Firstly, an algorithm based on color scene filed method is presented in order to digitize analog seismograms. Secondly, an interactive software program using C# has been developed to digitize seismogram traces from raster files quickly and accurately. The program can deal with gray-scale images stored in a suitable file format and it offers two different methods: manual digitization and automatic digitization. The test result of the program shows that the methods presented in this paper can lead to good performance.

  2. Conjecturing via Reconceived Classical Analogy

    Science.gov (United States)

    Lee, Kyeong-Hwa; Sriraman, Bharath

    2011-01-01

    Analogical reasoning is believed to be an efficient means of problem solving and construction of knowledge during the search for and the analysis of new mathematical objects. However, there is growing concern that despite everyday usage, learners are unable to transfer analogical reasoning to learning situations. This study aims at facilitating…

  3. Musik som analogi og metafor

    DEFF Research Database (Denmark)

    2014-01-01

    Indeholder underkapitlerne: 2.5.1 Musik som analogi 2.5.2 Musik som metafor 2.5.3 Musikkens psykologiske funktioner - en taxonomi og metaforisk lytning til fire baroksatser......Indeholder underkapitlerne: 2.5.1 Musik som analogi 2.5.2 Musik som metafor 2.5.3 Musikkens psykologiske funktioner - en taxonomi og metaforisk lytning til fire baroksatser...

  4. Natural analog studies: Licensing perspective

    Energy Technology Data Exchange (ETDEWEB)

    Bradbury, J.W. [Nuclear Regulatory Commission, Washington, DC (United States)

    1995-09-01

    This report describes the licensing perspective of the term {open_quotes}natural analog studies{close_quotes} as used in CFR Part 60. It describes the misunderstandings related to its definition which has become evident during discussions at the U.S Nuclear Regulatory Commission meetings and tries to clarify the appropriate applications of natural analog studies to aspects of repository site characterization.

  5. Distributed Episodic and Analogical Reasoning (DEAR)

    Science.gov (United States)

    2010-04-01

    ends analysis Carbonell 1983 Modeling of Analogy Making Structure Mapping Theory (SMT) Gentner 1984 Agent based approach to analogy making...Mapping Engine (SME) Forbus 1990 Learning by analogy with larger domains Prodigy/Analogy Veloso and Carbonell 1991 Analogical Retrieval Engine MAC/FAC

  6. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J M

    2010-01-01

    The design of an analog-to-digital converter or digital-to-analog converter is one of the most fascinating tasks in micro-electronics. In a converter the analog world with all its intricacies meets the realm of the formal digital abstraction. Both disciplines must be understood for an optimum conversion solution. In a converter also system challenges meet technology opportunities. Modern systems rely on analog-to-digital converters as an essential part of the complex chain to access the physical world. And processors need the ultimate performance of digital-to-analog converters to present the results of their complex algorithms. The same progress in CMOS technology that enables these VLSI digital systems creates new challenges for analog-to-digital converters: lower signal swings, less power and variability issues. Last but not least, the analog-to-digital converter must follow the cost reduction trend. These changing boundary conditions require micro-electronics engineers to consider their design choices for...

  7. High-speed analog-to-digital conversion

    CERN Document Server

    Demler, Michael J

    1991-01-01

    This book covers the theory and applications of high-speed analog-to-digital conversion. An analog-to-digital converter takes real-world inputs (such as visual images, temperature readings, and rates of speed) and transforms them into digital form for processing by computer. This book discusses the design and uses of such circuits, with particular emphasis on improving the speed of the conversion process and the accuracy of its output--how well the output is a corresponding digital representation of the output*b1input signal. As computers become increasingly interfaced to the outside world, ""

  8. Sulfonimidamide analogs of oncolytic sulfonylureas.

    Science.gov (United States)

    Toth, J E; Grindey, G B; Ehlhardt, W J; Ray, J E; Boder, G B; Bewley, J R; Klingerman, K K; Gates, S B; Rinzel, S M; Schultz, R M; Weir, L C; Worzalla, J F

    1997-03-14

    A series of sulfonimidamide analogs of the oncolytic diarylsulfonylureas was synthesized and evaluated for (1) in vitro cytotoxicity against CEM cells, (2) in vivo antitumor activity against subaxillary implanted 6C3HED lymphosarcoma, and (3) metabolic breakdown to the o-sulfate of p-chloroaniline. The separated enantiomers of one sulfonimidamide analog displayed very different activities in the in vivo screening model. In general, several analogs demonstrated excellent growth inhibitory activity in the 6C3HED model when dosed orally or intraperitoneally. A correlative structure-activity relationship to the oncolytic sulfonylureas was not apparent.

  9. Analog regulation of metabolic demand

    Directory of Open Access Journals (Sweden)

    Muskhelishvili Georgi

    2011-03-01

    Full Text Available Abstract Background The 3D structure of the chromosome of the model organism Escherichia coli is one key component of its gene regulatory machinery. This type of regulation mediated by topological transitions of the chromosomal DNA can be thought of as an analog control, complementing the digital control, i.e. the network of regulation mediated by dedicated transcription factors. It is known that alterations in the superhelical density of chromosomal DNA lead to a rich pattern of differential expressed genes. Using a network approach, we analyze these expression changes for wild type E. coli and mutants lacking nucleoid associated proteins (NAPs from a metabolic and transcriptional regulatory network perspective. Results We find a significantly higher correspondence between gene expression and metabolism for the wild type expression changes compared to mutants in NAPs, indicating that supercoiling induces meaningful metabolic adjustments. As soon as the underlying regulatory machinery is impeded (as for the NAP mutants, this coherence between expression changes and the metabolic network is substantially reduced. This effect is even more pronounced, when we compute a wild type metabolic flux distribution using flux balance analysis and restrict our analysis to active reactions. Furthermore, we are able to show that the regulatory control exhibited by DNA supercoiling is not mediated by the transcriptional regulatory network (TRN, as the consistency of the expression changes with the TRN logic of activation and suppression is strongly reduced in the wild type in comparison to the mutants. Conclusions So far, the rich patterns of gene expression changes induced by alterations of the superhelical density of chromosomal DNA have been difficult to interpret. Here we characterize the effective networks formed by supercoiling-induced gene expression changes mapped onto reconstructions of E. coli's metabolic and transcriptional regulatory network. Our

  10. A digital-analog hybrid system and its application to the automatic flight control system simulation research

    Science.gov (United States)

    1981-01-01

    The characteristics of a digital-analog hybrid system composed of a DJS-8 digital computer and a HMJ-200 analog computer are described as well as its applications to simulation research for an automatic flight control system. A hybrid computational example is included to illustrate the application.

  11. Analog implementation of pulse-coupled neural networks.

    Science.gov (United States)

    Ota, Y; Wilamowski, B M

    1999-01-01

    This paper presents a compact architecture for analog CMOS hardware implementation of voltage-mode pulse-coupled neural networks (PCNN's). The hardware implementation methods shows inherent fault tolerance specialties and high speed, which is usually more than an order of magnitude over the software counterpart. A computational style described in this article mimics a biological neural network using pulse-stream signaling and analog summation and multiplication. Pulse-stream encoding technique uses pulse streams to carry information and control analog circuitry, while storing further analog information on the time axis. The main feature of the proposed neuron circuit is that the structure is compact, yet exhibiting all the basic properties of natural biological neurons. Functional and structural forms of neural and synaptic functions are presented along with simulation results. Finally, the proposed design is applied to image processing to demonstrate successful restoration of images and their features.

  12. Biomedical sensor design using analog compressed sensing

    Science.gov (United States)

    Balouchestani, Mohammadreza; Krishnan, Sridhar

    2015-05-01

    The main drawback of current healthcare systems is the location-specific nature of the system due to the use of fixed/wired biomedical sensors. Since biomedical sensors are usually driven by a battery, power consumption is the most important factor determining the life of a biomedical sensor. They are also restricted by size, cost, and transmission capacity. Therefore, it is important to reduce the load of sampling by merging the sampling and compression steps to reduce the storage usage, transmission times, and power consumption in order to expand the current healthcare systems to Wireless Healthcare Systems (WHSs). In this work, we present an implementation of a low-power biomedical sensor using analog Compressed Sensing (CS) framework for sparse biomedical signals that addresses both the energy and telemetry bandwidth constraints of wearable and wireless Body-Area Networks (BANs). This architecture enables continuous data acquisition and compression of biomedical signals that are suitable for a variety of diagnostic and treatment purposes. At the transmitter side, an analog-CS framework is applied at the sensing step before Analog to Digital Converter (ADC) in order to generate the compressed version of the input analog bio-signal. At the receiver side, a reconstruction algorithm based on Restricted Isometry Property (RIP) condition is applied in order to reconstruct the original bio-signals form the compressed bio-signals with high probability and enough accuracy. We examine the proposed algorithm with healthy and neuropathy surface Electromyography (sEMG) signals. The proposed algorithm achieves a good level for Average Recognition Rate (ARR) at 93% and reconstruction accuracy at 98.9%. In addition, The proposed architecture reduces total computation time from 32 to 11.5 seconds at sampling-rate=29 % of Nyquist rate, Percentage Residual Difference (PRD)=26 %, Root Mean Squared Error (RMSE)=3 %.

  13. Analog CMOS contrastive Hebbian networks

    Science.gov (United States)

    Schneider, Christian; Card, Howard

    1992-09-01

    CMOS VLSI circuits implementing an analog neural network with on-chip contrastive Hebbian learning and capacitive synaptic weight storage have been designed and fabricated. Weights are refreshed by periodic repetition of the training data. To evaluate circuit performance in a medium-sized system, these circuits were used to build a 132 synapse neural network. An adaptive neural system, such as the one described in this paper, can compensate for imperfections in the components from which it is constructed, and thus it is possible to build this type of system using simple, silicon area-efficient analog circuits. Because these analog VLSI circuits are far more compact than their digital counterparts, analog VLSI neural network implementations are potentially more efficient than digital ones.

  14. Solving a problem by analogy

    Science.gov (United States)

    Easton, Don

    1999-03-01

    This note is a description of a student solution to a problem. I found the solution exciting because it exemplifies the kind of solution by analogy that Feynman describes in The Feynman Lectures on Physics.

  15. Analog filters in nanometer CMOS

    CERN Document Server

    Uhrmann, Heimo; Zimmermann, Horst

    2014-01-01

    Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

  16. Analog approach to mixed analog-digital circuit simulation

    Science.gov (United States)

    Ogrodzki, Jan

    2013-10-01

    Logic simulation of digital circuits is a well explored research area. Most up-to-date CAD tools for digital circuits simulation use an event driven, selective trace algorithm and Hardware Description Languages (HDL), e.g. the VHDL. This techniques enable simulation of mixed circuits, as well, where an analog part is connected to the digital one through D/A and A/D converters. The event-driven mixed simulation applies a unified, digital-circuits dedicated method to both digital and analog subsystems. In recent years HDL techniques have been also applied to mixed domains, as e.g. in the VHDL-AMS. This paper presents an approach dual to the event-driven one, where an analog part together with a digital one and with converters is treated as the analog subsystem and is simulated by means of circuit simulation techniques. In our problem an analog solver used yields some numerical problems caused by nonlinearities of digital elements. Efficient methods for overriding these difficulties have been proposed.

  17. Neural computation and the computational theory of cognition.

    Science.gov (United States)

    Piccinini, Gualtiero; Bahar, Sonya

    2013-04-01

    We begin by distinguishing computationalism from a number of other theses that are sometimes conflated with it. We also distinguish between several important kinds of computation: computation in a generic sense, digital computation, and analog computation. Then, we defend a weak version of computationalism-neural processes are computations in the generic sense. After that, we reject on empirical grounds the common assimilation of neural computation to either analog or digital computation, concluding that neural computation is sui generis. Analog computation requires continuous signals; digital computation requires strings of digits. But current neuroscientific evidence indicates that typical neural signals, such as spike trains, are graded like continuous signals but are constituted by discrete functional elements (spikes); thus, typical neural signals are neither continuous signals nor strings of digits. It follows that neural computation is sui generis. Finally, we highlight three important consequences of a proper understanding of neural computation for the theory of cognition. First, understanding neural computation requires a specially designed mathematical theory (or theories) rather than the mathematical theories of analog or digital computation. Second, several popular views about neural computation turn out to be incorrect. Third, computational theories of cognition that rely on non-neural notions of computation ought to be replaced or reinterpreted in terms of neural computation.

  18. Derivational Analogy: A Theory of Reconstructive Problem Solving and Expertise Acquisition.,

    Science.gov (United States)

    2014-09-26

    Failed attempts, and members of other clusters provide the negative exemplars to an induction engine. DERIVATIONAL ANALOGY 1. Introduction: The Role of...transformational analogy , has been successfully implemented in ARIES (An:logical Reasoning and Inductive Experimentation System) [9]. The second approach, called...RD-ARi5 917 DERIYATIONAL ANALOGY A THEORY OF RECONSTRUCTIVE 1/1 PROBLEM SOLVING RND EXPE..(U) CRRNEGIE-MELLON UNIV PITTSBURGH PR DEPT OF COMPUTER

  19. From specification to measurement: the bottleneck in analog industrial testing

    NARCIS (Netherlands)

    Rijsinge, van R.J.; Haggenburg, A.A.R.M.; Vries, de C.; Wallinga, H.

    1990-01-01

    The translation of the specification of an analog device into the necessary set of measurements to be carried out by an industrial test facility is discussed. Algorithms are developed to compute the number of test vectors needed to guarantee a certain parameter and to compare several possible test m

  20. All-optical analog comparator

    Science.gov (United States)

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-08-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function.

  1. Numerical Simulation and Water Analog of Mold Filling Processes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper demonstrates the potential of a computer code, developed by the authors, in shaping gating systems by modeling the fluid flow phenomena through a complex gating system during mold filling. A plate casting with dimension 200 mm×200 mm×50 mm was chosen as the verifying problem. Water analog studies were carried out on this casting. The comparison indicates that computer simulation could be a powerful tool in shaping gating systems.

  2. Test Wiseness and Analogy Test Performance

    Science.gov (United States)

    Moore, James C.

    1971-01-01

    Subjects received self instruction on how to approach analogy questions. Instruction was directed toward knowledge of the general format of analogy questions in standarized tests and the 15 types of relationships commonly asked for in analogy questions. An analogies post-test showed a significant effect for the group. (Author)

  3. Analog electronics for radiation detection

    CERN Document Server

    2016-01-01

    Analog Electronics for Radiation Detection showcases the latest advances in readout electronics for particle, or radiation, detectors. Featuring chapters written by international experts in their respective fields, this authoritative text: Defines the main design parameters of front-end circuitry developed in microelectronics technologies Explains the basis for the use of complementary metal oxide semiconductor (CMOS) image sensors for the detection of charged particles and other non-consumer applications Delivers an in-depth review of analog-to-digital converters (ADCs), evaluating the pros and cons of ADCs integrated at the pixel, column, and per-chip levels Describes incremental sigma delta ADCs, time-to-digital converter (TDC) architectures, and digital pulse-processing techniques complementary to analog processing Examines the fundamental parameters and front-end types associated with silicon photomultipliers used for single visible-light photon detection Discusses pixel sensors ...

  4. All-optical analog comparator

    OpenAIRE

    Pu Li; Xiaogang Yi; Xianglian Liu; Dongliang Zhao; Yongpeng Zhao; Yuncai Wang

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical device...

  5. Design and Analog VLSI Implementation of Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Prof. Bapuray.D.Yammenavar

    2011-07-01

    Full Text Available Nature has evolved highly advanced systems capable of performing complex computations, adoption and learning using analog computations. Furthermore nature has evolved techniques to deal with imprecise analog computations by using redundancy and massive connectivity. In this paper we are making use of Artificial Neural Network to demonstrate the way in which the biological system processes in analog domain. We are using 180nm CMOS VLSI technology for implementing circuits which performs arithmetic operations and for implementing Neural Network. The arithmetic circuits presented here are based on MOS transistors operating in subthreshold region. The basic blocks of artificial neuron are multiplier, adder and neuron activation function. The functionality of designed neural network is verified for analog operations like signal amplification and frequency multiplication. The network designed can be adopted for digital operations like AND, OR and NOT. The network realizes its functionality for the trained targets which is verified using simulation results. The schematic, Layout design and verification of proposed Neural Network is carried out using Cadence Virtuoso tool.

  6. Mathematical Analogy and Metaphorical Insight

    Science.gov (United States)

    Zwicky, Jan

    2010-01-01

    How are we to understand the power of certain literary metaphors? The author argues that the apprehension of good metaphors is importantly similar to the apprehension of fruitful mathematical analogies: both involve a structural realignment of vision. The author then explores consequences of this claim, drawing conceptually significant parallels…

  7. Geometrical Analogies in Mathematics Lessons

    Science.gov (United States)

    Eid, Wolfram

    2007-01-01

    A typical form of thinking to approach problem solutions humanly is thinking in analogous structures. Therefore school, especially mathematical lessons should help to form and to develop corresponding heuristic abilities of the pupils. In the contribution, a summary of possibilities of mathematics lessons regarding this shall particularly be…

  8. Schema Training in Analogical Reasoning.

    Science.gov (United States)

    Robins, Shani; Mayer, Richard E.

    1993-01-01

    In 3 experiments, 93, 97, and 86 college students, respectively, learned how to solve 20 verbal analogy problems and took transfer and memory tests. Results are inconsistent with active responding theory and further indicate that schema induction is maximized when the schemas are made salient and the cognitive system is not overloaded. (SLD)

  9. 49205 ANALOGE OG DIGITALE FILTRE

    DEFF Research Database (Denmark)

    Gaunholt, Hans

    1997-01-01

    Theese lecture notes treats the fundamental theory and the most commonly used design methods for passive- active and digital filters with special emphasis on microelectronic realizations. The lecture notes covers 75% of the material taught in the course 49205 Analog and Digital Filters...

  10. Analog Input Data Acquisition Software

    Science.gov (United States)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  11. International Alligator Rivers Analog Project

    Energy Technology Data Exchange (ETDEWEB)

    Bichard, G.F.

    1988-01-01

    The Australian Nuclear Science and Technology Organization (ANSTO), the Japan Atomic Energy Research Institute, the Swedish Nuclear Power Inspectorate, the U.K. Department of the Environment, the US Nuclear Regulatory Commission (NRC), and the Power Reactor and Nuclear Fuel Development Corporation of Japan are participating under the aegis of the Nuclear Energy Agency in the International Alligator Rivers Analog Project. The project has a duration of 3 yr, starting in 1988. The project has grown out of a research program on uranium ore bodies as analogs of high-level waste (HLW) repositories undertaken by ANSTO supported by the NRC. A primary objective of the project is to develop an approach to radionuclide transport model validation that may be used by the participants to support assessments of the safety of radioactive waste repositories. The approach involves integrating mathematical and physical modeling with hydrological and geochemical field and laboratory investigations of the analog site. The Koongarra uranium ore body has been chosen as the analog site because it has a secondary ore body that has formed over the past million years as a result of leaching by groundwater flowing through fractures in the primary ore body.

  12. Digital and analog gene circuits for biotechnology.

    Science.gov (United States)

    Roquet, Nathaniel; Lu, Timothy K

    2014-05-01

    Biotechnology offers the promise of valuable chemical production via microbial processing of renewable and inexpensive substrates. Thus far, static metabolic engineering strategies have enabled this field to advance industrial applications. However, the industrial scaling of statically engineered microbes inevitably creates inefficiencies due to variable conditions present in large-scale microbial cultures. Synthetic gene circuits that dynamically sense and regulate different molecules can resolve this issue by enabling cells to continuously adapt to variable conditions. These circuits also have the potential to enable next-generation production programs capable of autonomous transitioning between steps in a bioprocess. Here, we review the design and application of two main classes of dynamic gene circuits, digital and analog, for biotechnology. Within the context of these classes, we also discuss the potential benefits of digital-analog interconversion, memory, and multi-signal integration. Though synthetic gene circuits have largely been applied for cellular computation to date, we envision that utilizing them in biotechnology will enhance the efficiency and scope of biochemical production with living cells.

  13. Efficient Analog Circuits for Boolean Satisfiability

    CERN Document Server

    Yin, Xunzhao; Varga, Melinda; Ercsey-Ravasz, Maria; Toroczkai, Zoltan; Hu, Xiaobo Sharon

    2016-01-01

    Efficient solutions to NP-complete problems would significantly benefit both science and industry. However, such problems are intractable on digital computers based on the von Neumann architecture, thus creating the need for alternative solutions to tackle such problems. Recently, a deterministic, continuous-time dynamical system (CTDS) was proposed (Nature Physics, 7(12), 966 (2011)) to solve a representative NP-complete problem, Boolean Satisfiability (SAT). This solver shows polynomial analog time-complexity on even the hardest benchmark $k$-SAT ($k \\geq 3$) formulas, but at an energy cost through exponentially driven auxiliary variables. With some modifications to the CTDS equations, here we present a novel analog hardware SAT solver, AC-SAT, implementing the CTDS. AC-SAT is intended to be used as a co-processor, and with its modular design can be readily extended to different problem sizes. The circuit is designed and simulated based on a 32nm CMOS technology. SPICE simulation results show speedup factor...

  14. Carcinoma de células renales: estadificación prequirúrgica por tomografía computada y su analogía con la anatomía patológica Renal cell carcinoma: preoperative staging by computed tomography and its analogy to pathology

    Directory of Open Access Journals (Sweden)

    María Cinthya Ortega Hrescak

    2013-03-01

    Full Text Available Objetivo. Evaluar la correlación entre la estadificación preoperatoria de los carcinomas de células renales usando tomografía computada y los resultados anatomopatológicos de la pieza operatoria. Materiales y Métodos. Se llevó a cabo un estudio retrospectivo entre los años 2005 y 2011, tomando un total de 40 pacientes con diagnóstico presuntivo de carcinoma de células renales (CCR del Servicio de Urología, que habían sido sometidos a nefrectomía total o parcial. Se compararon diferentes parámetros del estudio imagenológico (tomografía computada y anatomopatológico de cada paciente y se evaluó qué reciprocidad existía entre la estadificación pre y posoperatoria según el TNM. Resultados. Los datos obtenidos mediante el estudio anatomopatológico de la pieza operatoria mostraron 28 lesiones limitadas al riñón (estadios T1 y T2, 3 lesiones con extensión perirrenal y a la vena renal (estadio T3a, 7 lesiones con compromiso de la vena cava (estadio T3b y 2 lesiones con extensión más allá de la fascia de Gerota (estadio T4. Se encontró una fuerza de concordancia casi perfecta entre la estadificación tomográfica y anatomopatológica (kappa = 0,87 con respecto al criterio T del TNM. Sólo 2 T1b (por estudio anatomopatológico fueron sobrediagnosticados como T2 (según tomografía computada y 2 T3b (según estudio anatomopatológico se subdiagnosticaron como T3a (según tomografía computada. Conclusión. La tomografía computada proporciona una buena delimitación y caracterización del carcinoma de células renales. El nivel de concordancia con el patrón de referencia más fiable (anatomía patológica resultó casi perfecto (k = 0,87 para la estadificación del estadio T.Objective. To evaluate the correlation between the preoperative staging of renal cell carcinoma by computed tomography (CT and histopathologic results of the surgical specimen. Materials and Methods. A retrospective study has been carried out in a total

  15. Analog Electronic Filters Theory, Design and Synthesis

    CERN Document Server

    Dimopoulos, Hercules G

    2012-01-01

    Filters are essential subsystems in a huge variety of electronic systems. Filter applications are innumerable; they are used for noise reduction, demodulation, signal detection, multiplexing, sampling, sound and speech processing, transmission line equalization and image processing, to name just a few. In practice, no electronic system can exist without filters. They can be found in everything from power supplies to mobile phones and hard disk drives and from loudspeakers and MP3 players to home cinema systems and broadband Internet connections. This textbook introduces basic concepts and methods and the associated mathematical and computational tools employed in electronic filter theory, synthesis and design.  This book can be used as an integral part of undergraduate courses on analog electronic filters. Includes numerous, solved examples, applied examples and exercises for each chapter. Includes detailed coverage of active and passive filters in an independent but correlated manner. Emphasizes real filter...

  16. Analog circuit design art, science and personalities

    CERN Document Server

    Williams, Jim

    1991-01-01

    This book is far more than just another tutorial or reference guide - it's a tour through the world of analog design, combining theory and applications with the philosophies behind the design process. Readers will learn how leading analog circuit designers approach problems and how they think about solutions to those problems. They'll also learn about the `analog way' - a broad, flexible method of thinking about analog design tasks.A comprehensive and useful guide to analog theory and applications. Covers visualizing the operation of analog circuits. Looks at how to rap

  17. Computer immunology.

    Science.gov (United States)

    Forrest, Stephanie; Beauchemin, Catherine

    2007-04-01

    This review describes a body of work on computational immune systems that behave analogously to the natural immune system. These artificial immune systems (AIS) simulate the behavior of the natural immune system and in some cases have been used to solve practical engineering problems such as computer security. AIS have several strengths that can complement wet lab immunology. It is easier to conduct simulation experiments and to vary experimental conditions, for example, to rule out hypotheses; it is easier to isolate a single mechanism to test hypotheses about how it functions; agent-based models of the immune system can integrate data from several different experiments into a single in silico experimental system.

  18. Holism and nonseparability by analogy

    Science.gov (United States)

    Arageorgis, Aristidis

    2013-08-01

    This paper explores the issues of holism and nonseparability in relativistic quantum field theory (QFT) by focusing on an analog of the typical model featuring in many discussions of holism and nonseparability in nonrelativistic quantum mechanics. It is argued that the quantum field theoretic model does exhibit holism in a metaphysical sense and that there are plausible grounds to view QFT holistic in an epistemological sense. However, the complexities arising from the fact that quantum fields have infinite degrees of freedom prohibit the exploitation of the elaborated analogy toward demonstrating that the QFT model exhibits the kind of state nonseparability familiar from ordinary quantum mechanics. Still, it is argued that the QFT model does satisfy a rather weak epistemological criterion for state nonseparability.

  19. Mechanical Analogies of Fractional Elements

    Institute of Scientific and Technical Information of China (English)

    HU Kai-Xin; ZHU Ke-Qin

    2009-01-01

    A Fractional element model describes a special kind of viscoelastic material.Its stress is proportional to the fractional-order derivative of strain. Physically the mechanical analogies of fractional elements can be represented by spring-dashpot fractal networks. We introduce a constitutive operator in the constitutive equations of viscoelastic materials.To derive constitutive operators for spring-dashpot fractal networks, we use Heaviside operational calculus, which provides explicit answers not otherwise obtainable simply.Then the series-parallel formulas for the constitutive operator are derived. Using these formulas, a constitutive equation of fractional element with 1/2-order derivative is obtained.Finally we find the way to derive the constitutive equations with other fractional-order derivatives and their mechanical analogies.

  20. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel

    2017-01-01

    This textbook is appropriate for use in graduate-level curricula in analog-to-digital conversion, as well as for practicing engineers in need of a state-of-the-art reference on data converters. It discusses various analog-to-digital conversion principles, including sampling, quantization, reference generation, nyquist architectures and sigma-delta modulation. This book presents an overview of the state of the art in this field and focuses on issues of optimizing accuracy and speed, while reducing the power level. This new, third edition emphasizes novel calibration concepts, the specific requirements of new systems, the consequences of 22-nm technology and the need for a more statistical approach to accuracy. Pedagogical enhancements to this edition include additional, new exercises, solved examples to introduce all key, new concepts and warnings, remarks and hints, from a practitioner’s perspective, wherever appropriate. Considerable background information and practical tips, from designing a PCB, to lay-o...

  1. Low Power CMOS Analog Multiplier

    Directory of Open Access Journals (Sweden)

    Shipra Sachan

    2015-12-01

    Full Text Available In this paper Low power low voltage CMOS analog multiplier circuit is proposed. It is based on flipped voltage follower. It consists of four voltage adders and a multiplier core. The circuit is analyzed and designed in 0.18um CMOS process model and simulation results have shown that, under single 0.9V supply voltage, and it consumes only 31.8µW quiescent power and 110MHZ bandwidth.

  2. A global analog of Cheshire charge

    CERN Document Server

    McGraw, P

    1994-01-01

    It is shown that a model with a spontaneously broken global symmetry can support defects analogous to Alice strings, and a process analogous to Cheshire charge exchange can take place. A possible realization in superfluid He-3 is pointed out.

  3. Investigating visual analogies for visual insight problems

    OpenAIRE

    Corina Sas; Eric Luchian; Linden Ball

    2010-01-01

    Much research has focused on the impact of analogies in insight problem solving, but less work has investigated how the visual analogies for insight are actually constructed. Thus, it appears that in the search for their facilitative impact on the incubation effect, the understanding of what makes good visual analogies has somehow been lost. This paper presents preliminary work of constructing a set of 6 visual analogies and evaluating their impact on solving the visual problem of eight coins...

  4. Hegel, Analogy, and Extraterrestrial Life

    Science.gov (United States)

    Ross, Joseph T.

    Georg Wilhelm Friedrich Hegel rejected the possibility of life outside of the Earth, according to several scholars of extraterrestrial life. Their position is that the solar system and specifically the planet Earth is the unique place in the cosmos where life, intelligence, and rationality can be. The present study offers a very different interpretation of Hegel's statements about the place of life on Earth by suggesting that, although Hegel did not believe that there were other solar systems where rationality is present, he did in fact suggest that planets in general, not the Earth exclusively, have life and possibly also intelligent inhabitants. Analogical syllogisms are superficial, according to Hegel, insofar as they try to conclude that there is life on the Moon even though there is no evidence of water or air on that body. Similar analogical arguments for life on the Sun made by Johann Elert Bode and William Herschel were considered by Hegel to be equally superficial. Analogical arguments were also used by astronomers and philosophers to suggest that life could be found on other planets in our solar system. Hegel offers no critique of analogical arguments for life on other planets, and in fact Hegel believed that life would be found on other planets. Planets, after all, have meteorological processes and therefore are "living" according to his philosophical account, unlike the Moon, Sun, and comets. Whereas William Herschel was already finding great similarities between the Sun and the stars and had extended these similarities to the property of having planets or being themselves inhabitable worlds, Hegel rejected this analogy. The Sun and stars have some properties in common, but for Hegel one cannot conclude from these similarities to the necessity that stars have planets. Hegel's arguments against the presence of life in the solar system were not directed against other planets, but rather against the Sun and Moon, both of which he said have a different

  5. Analogical Reasoning: A Review of the Literature.

    Science.gov (United States)

    Dawis, Rene V.; Siojo, Luis T.

    The mathematical and philosophical origins of "analogy" are described and their influence on the thinking of intelligence theorists is traced. Theories of intelligence and cognition bearing on analogical reasoning are examined, specifically those of Spearman, Thorndike, Guilford and Piaget. The analogy test item is shown to be a paradigm…

  6. Reasoning by Analogy in Constructing Mathematical Ideas.

    Science.gov (United States)

    English, Lyn D.

    A powerful way of understanding something new is by analogy with something already known. An analogy is defined as a mapping from one structure, which is already known (the base or source), to another structure that is to be inferred or discovered (the target). The research community has given considerable attention to analogical reasoning in the…

  7. Analog circuit design art, science, and personalities

    CERN Document Server

    Williams, Jim

    1991-01-01

    Analog Circuit Design: Art, Science, and Personalities discusses the many approaches and styles in the practice of analog circuit design. The book is written in an informal yet informative manner, making it easily understandable to those new in the field. The selection covers the definition, history, current practice, and future direction of analog design; the practice proper; and the styles in analog circuit design. The book also includes the problems usually encountered in analog circuit design; approach to feedback loop design; and other different techniques and applications. The text is

  8. Analog and mixed-signal electronics

    CERN Document Server

    Stephan, Karl

    2015-01-01

    A practical guide to analog and mixed-signal electronics, with an emphasis on design problems and applications This book provides an in-depth coverage of essential analog and mixed-signal topics such as power amplifiers, active filters, noise and dynamic range, analog-to-digital and digital-to-analog conversion techniques, phase-locked loops, and switching power supplies. Readers will learn the basics of linear systems, types of nonlinearities and their effects, op-amp circuits, the high-gain analog filter-amplifier, and signal generation. The author uses system design examples to motivate

  9. Practical analog electronics for technicians

    CERN Document Server

    Kimber, W A

    2013-01-01

    'Practical Analog Electronics for Technicians' not only provides an accessible introduction to electronics, but also supplies all the problems and practical activities needed to gain hands-on knowledge and experience. This emphasis on practice is surprisingly unusual in electronics texts, and has already gained Will Kimber popularity through the companion volume, 'Practical Digital Electronics for Technicians'. Written to cover the Advanced GNVQ optional unit in electronics, this book is also ideal for BTEC National, A-level electronics and City & Guilds courses. Together with 'Practical Digit

  10. Automating analog design: Taming the shrew

    Science.gov (United States)

    Barlow, A.

    1990-01-01

    The pace of progress in the design of integrated circuits continues to amaze observers inside and outside of the industry. Three decades ago, a 50 transistor chip was a technological wonder. Fifteen year later, a 5000 transistor device would 'wow' the crowds. Today, 50,000 transistor chips will earn a 'not too bad' assessment, but it takes 500,000 to really leave an impression. In 1975 a typical ASIC device had 1000 transistors, took one year to first samples (and two years to production) and sold for about 5 cents per transistor. Today's 50,000 transistor gate array takes about 4 months from spec to silicon, works the first time, and sells for about 0.02 cents per transistor. Fifteen years ago, the single most laborious and error prone step in IC design was the physical layout. Today, most IC's never see the hand of a layout designer: and automatic place and route tool converts the engineer's computer captured schematic to a complete physical design using a gate array or a library of standard cells also created by software rather than by designers. CAD has also been a generous benefactor to the digital design process. The architect of today's digital systems creates the design using an RTL or other high level simulator. Then the designer pushes a button to invoke the logic synthesizer-optimizer tool. A fault analyzer checks the result for testability and suggests where scan based cells will improve test coverage. One obstinate holdout amidst this parade of progress is the automation of analog design and its reduction to semi-custom techniques. This paper investigates the application of CAD techniques to analog design.

  11. Transfer Between Analogies: How Solving One Analogy Problem Helps to Solve Another

    OpenAIRE

    Keane, Mark T.

    1995-01-01

    This paper deals with transfer between analogies; with what people acquire from one analogy problem-solving episode that can be re-applied to a subsequent analogy, problem-solving episode. This issue must be resolved if we are to understand the nature of expertise and the appropriate use of analogy in education. There are two main explanations of what subjects acquire from an analogy problem-solving episode. The schema-induction hypothesis maintains that subjects acquire an abs...

  12. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J. M

    2013-01-01

    This textbook is appropriate for use in graduate-level curricula in analog to digital conversion, as well as for practicing engineers in need of a state-of-the-art reference on data converters.  It discusses various analog-to-digital conversion principles, including sampling, quantization, reference generation, nyquist architectures and sigma-delta modulation.  This book presents an overview of the state-of-the-art in this field and focuses on issues of optimizing accuracy and speed, while reducing the power level. This new, second edition emphasizes novel calibration concepts, the specific requirements of new systems, the consequences of 45-nm technology and the need for a more statistical approach to accuracy.  Pedagogical enhancements to this edition include more than twice the exercises available in the first edition, solved examples to introduce all key, new concepts and warnings, remarks and hints, from a practitioner’s perspective, wherever appropriate.  Considerable background information and pr...

  13. A least mean squares CUBIC algorithm for on-line differential of sampled analog signals

    Science.gov (United States)

    Allum, J. H. J.

    1975-01-01

    A digital computer algorithm is developed for on-line time differentiation of sampled analog voltage signals. The derivative is obtained by employing a least mean squares technique. The recursive algorithm results in a considerable reduction in computer time compared to a complete new solution of the normal equations each time a new data point is accepted. Implementation of the algorithm on a digital computer is discussed. Examples are simulated on a DEC PDP-8 computer.

  14. Advances in unconventional computing

    CERN Document Server

    2017-01-01

    The unconventional computing is a niche for interdisciplinary science, cross-bred of computer science, physics, mathematics, chemistry, electronic engineering, biology, material science and nanotechnology. The aims of this book are to uncover and exploit principles and mechanisms of information processing in and functional properties of physical, chemical and living systems to develop efficient algorithms, design optimal architectures and manufacture working prototypes of future and emergent computing devices. This first volume presents theoretical foundations of the future and emergent computing paradigms and architectures. The topics covered are computability, (non-)universality and complexity of computation; physics of computation, analog and quantum computing; reversible and asynchronous devices; cellular automata and other mathematical machines; P-systems and cellular computing; infinity and spatial computation; chemical and reservoir computing. The book is the encyclopedia, the first ever complete autho...

  15. Chromatin computation.

    Directory of Open Access Journals (Sweden)

    Barbara Bryant

    Full Text Available In living cells, DNA is packaged along with protein and RNA into chromatin. Chemical modifications to nucleotides and histone proteins are added, removed and recognized by multi-functional molecular complexes. Here I define a new computational model, in which chromatin modifications are information units that can be written onto a one-dimensional string of nucleosomes, analogous to the symbols written onto cells of a Turing machine tape, and chromatin-modifying complexes are modeled as read-write rules that operate on a finite set of adjacent nucleosomes. I illustrate the use of this "chromatin computer" to solve an instance of the Hamiltonian path problem. I prove that chromatin computers are computationally universal--and therefore more powerful than the logic circuits often used to model transcription factor control of gene expression. Features of biological chromatin provide a rich instruction set for efficient computation of nontrivial algorithms in biological time scales. Modeling chromatin as a computer shifts how we think about chromatin function, suggests new approaches to medical intervention, and lays the groundwork for the engineering of a new class of biological computing machines.

  16. Automatic Synthesis of CMOS Algorithmic Analog To-Digital Converter.

    Science.gov (United States)

    Jusuf, Gani

    The steady decrease in technological feature size is allowing increasing levels of integration in analog/digital interface functions. These functions consist of analog as well as digital circuits. While the turn around time for an all digital IC chip is very short due to the maturity of digital IC computer-aided design (CAD) tools over the last ten years, most analog circuits have to be designed manually due to the lack of analog IC CAD tools. As a result, analog circuit design becomes the bottleneck in the design of mixed signal processing chips. One common analog function in a mixed signal processing chip is an analog-to-digital conversion (ADC) function. This function recurs frequently but with varying performance requirements. The objective of this research is to study the design methodology of a compilation program capable of synthesizing ADC's with a broad range of sampling rates and resolution, and silicon area and performance comparable with the manual approach. The automatic compilation of the ADC function is a difficult problem mainly because ADC techniques span such a wide spectrum of performance, with radically different implementations being optimum for different ranges of conversion range, resolution, and power dissipation. We will show that a proper choice of the ADC architectures and the incorporation of many analog circuit design techniques will simplify the synthesis procedure tremendously. Moreover, in order to speed up the device sizing, hierarchical optimization procedure and behavioral simulation are implemented into the ADC module generation steps. As a result of this study, a new improved algorithmic ADC without the need of high precision comparators has been developed. This type of ADC lends itself to automatic generation due to its modularity, simplicity, small area consumption, moderate speed, low power dissipation, and single parameter trim capability that can be added at high resolution. Furthermore, a performance-driven CMOS ADC module

  17. Varieties of noise: analogical reasoning in synthetic biology.

    Science.gov (United States)

    Knuuttila, Tarja; Loettgers, Andrea

    2014-12-01

    The picture of synthetic biology as a kind of engineering science has largely created the public understanding of this novel field, covering both its promises and risks. In this paper, we will argue that the actual situation is more nuanced and complex. Synthetic biology is a highly interdisciplinary field of research located at the interface of physics, chemistry, biology, and computational science. All of these fields provide concepts, metaphors, mathematical tools, and models, which are typically utilized by synthetic biologists by drawing analogies between the different fields of inquiry. We will study analogical reasoning in synthetic biology through the emergence of the functional meaning of noise, which marks an important shift in how engineering concepts are employed in this field. The notion of noise serves also to highlight the differences between the two branches of synthetic biology: the basic science-oriented branch and the engineering-oriented branch, which differ from each other in the way they draw analogies to various other fields of study. Moreover, we show that fixing the mapping between a source domain and the target domain seems not to be the goal of analogical reasoning in actual scientific practice.

  18. Priming analogical reasoning with false memories.

    Science.gov (United States)

    Howe, Mark L; Garner, Sarah R; Threadgold, Emma; Ball, Linden J

    2015-08-01

    Like true memories, false memories are capable of priming answers to insight-based problems. Recent research has attempted to extend this paradigm to more advanced problem-solving tasks, including those involving verbal analogical reasoning. However, these experiments are constrained inasmuch as problem solutions could be generated via spreading activation mechanisms (much like false memories themselves) rather than using complex reasoning processes. In three experiments we examined false memory priming of complex analogical reasoning tasks in the absence of simple semantic associations. In Experiment 1, we demonstrated the robustness of false memory priming in analogical reasoning when backward associative strength among the problem terms was eliminated. In Experiments 2a and 2b, we extended these findings by demonstrating priming on newly created homonym analogies that can only be solved by inhibiting semantic associations within the analogy. Overall, the findings of the present experiments provide evidence that the efficacy of false memory priming extends to complex analogical reasoning problems.

  19. Design and Analysis of Reconfigurable Analog System

    Science.gov (United States)

    2011-02-01

    34010010" �" �" �" �" �" �" �±" N3 N2 N± P1 P2 P3 * Current sources $RR = 1; *Ramp Rate (slope of the...2008/12/12/31e83bac-500f-4182- acca -4d360295fd9c.pdf, Analog Devices, Analog Dialogue 39-06, June 2005. [15] D. A. Johns, K. Martin "Analog Integrated

  20. Robust hyperchaotic synchronization via analog transmission line

    Science.gov (United States)

    Sadoudi, S.; Tanougast, C.

    2016-02-01

    In this paper, a novel experimental chaotic synchronization technique via analog transmission is discussed. We demonstrate through Field-Programmable Gate Array (FPGA) implementation design the robust synchronization of two embedded hyperchaotic Lorenz generators interconnected with an analog transmission line. The basic idea of this work consists in combining a numerical generation of chaos and transmitting it with an analog signal. The numerical chaos allows to overcome the callback parameter mismatch problem and the analog transmission offers robust data security. As application, this technique can be applied to all families of chaotic systems including time-delayed chaotic systems.

  1. Fermilab accelerator control system: Analog monitoring facilities

    Energy Technology Data Exchange (ETDEWEB)

    Seino, K.; Anderson, L.; Smedinghoff, J.

    1987-10-01

    Thousands of analog signals are monitored in different areas of the Fermilab accelerator complex. For general purposes, analog signals are sent over coaxial or twinaxial cables with varying lengths, collected at fan-in boxes and digitized with 12 bit multiplexed ADCs. For higher resolution requirements, analog signals are digitized at sources and are serially sent to the control system. This paper surveys ADC subsystems that are used with the accelerator control systems and discusses practical problems and solutions, and it describes how analog data are presented on the console system.

  2. Neural correlates of intelligence as revealed by fMRI of fluid analogies.

    Science.gov (United States)

    Geake, John G; Hansen, Peter C

    2005-06-01

    It has been conjectured that the cognitive basis of intelligence is the ability to make fluid or creative analogical relationships between distantly related concepts or pieces of information (Hofstadter, D.R. 1995. Fluid Concepts and Creative Analogies. Basic Books, New York., Hofstadter, D.R. 2001. Analogy as the Core of Cognition. In The Analogical Mind: Perspectives from Cognitive Science (D. Gentner, K. J. Holyoak and B. N. Kokinov, Ed.). pp. 504-537. MIT Press, Cambridge, Mass.). We hypothesised that fluid analogy-making tasks would activate specific regions of frontal cortex that were common to those of previous inferential reasoning tasks. We report here a novel self-paced event-related fMRI study employed to investigate the neural correlates of intelligence associated with undertaking fluid letter string analogy tasks. Stimuli were adapted from items of the AI program Copycat (Mitchell, M. 1993. Analogy-making as Perception: A computer model. The MIT Press, Cambridge MA.). Twelve right-handed adults chose their own "best" completions from four plausible response choices to 55 fluid letter string analogies across a range of analogical depths. An analysis using covariates determined per subject by analogical depth revealed significant bilateral neural activations in the superior, inferior, and middle frontal gyri and in the anterior cingulate/paracingulate cortex. These frontal areas have been previously associated with reasoning tasks involving inductive syllogisms, syntactic hierarchies, and linguistic creativity. A higher-order analysis covarying participants' verbal intelligence measures found correlations with individual BOLD activation strengths in two ROIs within BA 9 and BA 45/46. This is a provocative result given that verbal intelligence is conceptualised as being a measure of crystallised intelligence, while analogy making is conceptualised as requiring fluid intelligence. The results therefore support the conjecture that fluid analogising could

  3. Analog Signal Processing Approach for Coarse and Fine Depth Estimation

    Directory of Open Access Journals (Sweden)

    Nihar Athreyas

    2014-12-01

    Full Text Available Imaging and Image sensors is a field that is continuously evolving. There are new products coming into the market every day. Some of these have very severe Size, Weight and Power constraints whereas other devices have to handle very high computational loads. Some require both these conditions to be met simultaneously. Current imaging architectures and digital image processing solutions will not be able to meet these ever increasing demands. There is a need to develop novel imaging architectures and image processing solutions to address these requirements. In this work we propose analog signal processing as a solution to this problem. The analog processor is not suggested as a replacement to a digital processor but it will be used as an augmentation device which works in parallel with the digital processor, making the system faster and more efficient. In order to show the merits of analog processing two stereo correspondence algorithms are implemented. We propose novel modifications to the algorithms and new imaging architectures which, significantly reduces the computation time

  4. Nitrogen analogs of TEX e A computational study

    Institute of Scientific and Technical Information of China (English)

    Lemi TU¨ RKER

    2014-01-01

    TEX, a well-known nitramine type explosive, has been subjected to centric perturbations by replacing its etheric (acetal) oxygens with nitrogen atoms one by one. The structural features, stabilities and IR and UV-VIS spectra of new structures formed are investigated. For this purpose, density functional theory has been employed at the B3LYP/6-31G (d,p) and B3LYP/6-311G(d) levels. In general the calculations revealed that the oxygenenitrogen replacement resulted in more energetic but less sensitive structures than TEX.

  5. CMOS analog integrated circuit design technology; CMOS anarogu IC sekkei gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, H.; Fujisawa, A. [Fuji Electric Co. Ltd., Tokyo (Japan)

    2000-08-10

    In the field of the LSI (large scale integrated circuit) in rapid progress toward high integration and advanced functions, CAD (computer-aided design) technology has become indispensable to LSI development within a short period. Fuji Electric has developed design technologies and automatic design system to develop high-quality analog ICs (integrated circuits), including power supply ICs. within a short period. This paper describes CMOS (complementary metal-oxide semiconductor) analog macro cell, circuit simulation, automatic routing, and backannotation technologies. (author)

  6. Strong Analog Classical Simulation of Coherent Quantum Dynamics

    Science.gov (United States)

    Wang, Dong-Sheng

    2017-02-01

    A strong analog classical simulation of general quantum evolution is proposed, which serves as a novel scheme in quantum computation and simulation. The scheme employs the approach of geometric quantum mechanics and quantum informational technique of quantum tomography, which applies broadly to cases of mixed states, nonunitary evolution, and infinite dimensional systems. The simulation provides an intriguing classical picture to probe quantum phenomena, namely, a coherent quantum dynamics can be viewed as a globally constrained classical Hamiltonian dynamics of a collection of coupled particles or strings. Efficiency analysis reveals a fundamental difference between the locality in real space and locality in Hilbert space, the latter enables efficient strong analog classical simulations. Examples are also studied to highlight the differences and gaps among various simulation methods. Funding support from NSERC of Canada and a research fellowship at Department of Physics and Astronomy, University of British Columbia are acknowledged

  7. A physical analogy to fuzzy clustering

    DEFF Research Database (Denmark)

    Jantzen, Jan

    2004-01-01

    This tutorial paper provides an interpretation of the membership assignment in the fuzzy clustering algorithm fuzzy c-means. The membership of a data point to several clusters is shown to be analogous to the gravitational forces between bodies of mass. This provides an alternative way to explain...... the algorithm to students. The analogy suggests a possible extension of the fuzzy membership assignment equation....

  8. PEMETAAN ANALOGI PADA KONSEP ABSTRAK FISIKA

    Directory of Open Access Journals (Sweden)

    Nyoto Suseno

    2014-11-01

    Full Text Available The research of any where founded majority students have common difficulties in abstract physics concept. The result of observation, lecturers have problem  in teaching implementation of abstract concepts on physics learning. The objective of this research is to find out the ways how to overcome this problem. The research place of  physics education programs and senior high school. The data are colected by quetionere, observation and interview. The lecturer behavior to making out this case is use of analogy to make concrete a abstract concept. This action is true, because the analogies are dynamic tools that facilitate understanding, rather than representations of the correct and static explanations. Using analogies not only promoted profound understanding of abstract concept, but also helped students overcome their misconceptions. However used analogy in teaching not yet planed with seriousness, analogy used spontanously with the result that less optimal. By planing and selecting right analogy, the role of analogy can be achieved the optimal result. Therefore, it is important to maping analogies of abstract consepts on physics learning.

  9. A Mechanical Analogy for the Photoelectric Effect

    Science.gov (United States)

    Kovacevic, Milan S.; Djordjevich, Alexandar

    2006-01-01

    Analogy is a potent tool in the teacher's repertoire. It has been particularly well recognized in the teaching of science. However, careful planning is required for its effective application to prevent documented drawbacks when analogies are stretched too far. Befitting the occasion of the World Year of Physics commemorating Albert Einstein's 1905…

  10. Analogies in high school Brazilian chemistry textbooks

    Directory of Open Access Journals (Sweden)

    Rosária Justi

    2000-05-01

    Full Text Available This paper presents and discusses an analysis of the analogies presented by Brazilian chemistry textbooks for the medium level. The main aim of the analysis is to discuss whether such analogies can be said good teaching models. From the results, some aspects concerning with teachers' role are discussed. Finally, some new research questions are emphasised.

  11. Antibacterial and Antibiofilm Activities of Makaluvamine Analogs

    Directory of Open Access Journals (Sweden)

    Bhavitavya Nijampatnam

    2014-09-01

    Full Text Available Streptococcus mutans is a key etiological agent in the formation of dental caries. The major virulence factor is its ability to form biofilms. Inhibition of S. mutans biofilms offers therapeutic prospects for the treatment and the prevention of dental caries. In this study, 14 analogs of makaluvamine, a marine alkaloid, were evaluated for their antibacterial activity against S. mutans and for their ability to inhibit S. mutans biofilm formation. All analogs contained the tricyclic pyrroloiminoquinone core of makaluvamines. The structural variations of the analogs are on the amino substituents at the 7-position of the ring and the inclusion of a tosyl group on the pyrrole ring N of the makaluvamine core. The makaluvamine analogs displayed biofilm inhibition with IC50 values ranging from 0.4 μM to 88 μM. Further, the observed bactericidal activity of the majority of the analogs was found to be consistent with the anti-biofilm activity, leading to the conclusion that the anti-biofilm activity of these analogs stems from their ability to kill S. mutans. However, three of the most potent N-tosyl analogs showed biofilm IC50 values at least an order of magnitude lower than that of bactericidal activity, indicating that the biofilm activity of these analogs is more selective and perhaps independent of bactericidal activity.

  12. Compressed Sensing of Analog Signals

    CERN Document Server

    Eldar, Yonina C

    2008-01-01

    A traditional assumption underlying most data converters is that the signal should be sampled at a rate which exceeds twice the highest frequency. This statement is based on a worst-case scenario in which the signal occupies the entire available bandwidth. In practice, many signals posses a sparse structure so that a large part of the bandwidth is not exploited. In this paper, we consider a framework for utilizing this sparsity in order to sample such analog signals at a low rate. More specifically, we consider continuous-time signals that lie in a shift-invariant (SI) space generated by m kernels, so that any signal in the space can be expressed as an infinite linear combination of the shifted kernels. If the period of the underlying SI space is equal to T, then such signals can be perfectly reconstructed from samples at a rate of m/T. Here we treat the case in which only k out of the m generators are active, meaning that the signal actually lies in a lower dimensional space spanned by k generators. However,...

  13. Novel Analog For Muscle Deconditioning

    Science.gov (United States)

    Ploutz-Snyder, Lori; Ryder, Jeff; Buxton, Roxanne; Redd. Elizabeth; Scott-Pandorf, Melissa; Hackney, Kyle; Fiedler, James; Ploutz-Snyder, Robert; Bloomberg, Jacob

    2011-01-01

    Existing models (such as bed rest) of muscle deconditioning are cumbersome and expensive. We propose a new model utilizing a weighted suit to manipulate strength, power, or endurance (function) relative to body weight (BW). Methods: 20 subjects performed 7 occupational astronaut tasks while wearing a suit weighted with 0-120% of BW. Models of the full relationship between muscle function/BW and task completion time were developed using fractional polynomial regression and verified by the addition of pre-and postflightastronaut performance data for the same tasks. Splineregression was used to identify muscle function thresholds below which task performance was impaired. Results: Thresholds of performance decline were identified for each task. Seated egress & walk (most difficult task) showed thresholds of leg press (LP) isometric peak force/BW of 18 N/kg, LP power/BW of 18 W/kg, LP work/BW of 79 J/kg, isokineticknee extension (KE)/BW of 6 Nm/kg, and KE torque/BW of 1.9 Nm/kg.Conclusions: Laboratory manipulation of relative strength has promise as an appropriate analog for spaceflight-induced loss of muscle function, for predicting occupational task performance and establishing operationally relevant strength thresholds.

  14. An optical analog signal transmitter

    Energy Technology Data Exchange (ETDEWEB)

    Fudzita, K.; Itida, T.; Tanaka, Kh.

    1984-01-11

    An optical laser analog signal transmitter employing an amplitude modulated subcarrier is patented; this transmitter performs stable and high quality transmission of information signals over great distances. A feature of the proposed transmitter is a special transmitter operational mode in which the light emission reflected off the connection point to the fiber optic conduit is sent back to the laser diode in a transient period. As a result, the critical mode of the generated emission is not influenced by the reflected signal. The transmitter consists of a laser diode with biasing near the cutoff point, an amplitude modulator with a subcarrier frequency oscillator, a section of flexible fiber-optic cable of length L, which connects the laser diode to the primary optical fiber conduit, and the connector itself. The subcarrier frequency may vary over wide ranges to establish the necessary correlation between the length of the light conduit section L and the return propagation time of the reflected light signal from the connection point to the laser diode. The difference between the lasing time of the light signal and the return time to the laser diode of the signal reflected off the connector is determined by the relation tau equals 2nL/c - mtauc, where L is the length of the connecting section; n is the refractivity of the optical fiber; c is the velocity of light; tauc is the period of the high frequency subcarrier signal; and m is an integer.

  15. Demonstrative and non-demonstrative reasoning by analogy

    OpenAIRE

    Ippoliti, Emiliano

    2008-01-01

    The paper analizes a set of issues related to analogy and analogical reasoning, namely: 1) The problem of analogy and its duplicity; 2) The role of analogy in demonstrative reasoning; 3) The role of analogy in non-demonstrative reasoning; 4) The limits of analogy; 5) The convergence, particularly in multiple analogical reasoning, of these two apparently distinct aspects and its methodological and philosophical consequences. The paper, using example from number theory, argues for an heuristc c...

  16. An Analog Earth Climate Model

    Science.gov (United States)

    Varekamp, J. C.

    2010-12-01

    The earth climate is broadly governed by the radiative power of the sun as well as the heat retention and convective cooling of the atmosphere. I have constructed an analog earth model for an undergraduate climate class that simulates mean climate using these three parameters. The ‘earth’ is a hollow, black, bronze sphere (4 cm diameter) mounted on a thin insulated rod, and illuminated by two opposite optic fibers, with light focused on the sphere by a set of lenses. The sphere is encased in a large double-walled aluminum cylinder (34 cm diameter by 26 cm high) with separate water cooling jackets at the top, bottom, and sides. The cylinder can be filled with a gas of choice at a variety of pressures or can be run in vacuum. The exterior is cladded with insulation, and the temperature of the sphere, atmosphere and walls is monitored with thermocouples. The temperature and waterflow of the three cooling jackets can be monitored to establish the energy output of the whole system; the energy input is the energy yield of the two optic fibers. A small IR transmissive lens at the top provides the opportunity to hook up the fiber of a hyper spectrometer to monitor the emission spectrum of the black ‘earth’ sphere. A pressure gauge and gas inlet-outlet system for flushing of the cell completes it. The heat yield of the cooling water at the top is the sum of the radiative and convective components, whereas the bottom jacket only carries off the radiative heat of the sphere. Undergraduate E&ES students at Wesleyan University have run experiments with dry air, pure CO2, N2 and Ar at 1 atmosphere, and a low vacuum run was accomplished to calibrate the energy input. For each experiment, the lights are flipped on, the temperature acquisition routine is activated, and the sphere starts to warm up until an equilibrium temperature has been reached. The lights are then flipped off and the cooling sequence towards ambient is registered. The energy input is constant for a given

  17. Namibian Analogs To Titan Dunes

    Science.gov (United States)

    Wall, Stephen D.; Lopes, R.; Kirk, R.; Stofan, E.; Farr, T.; Van der Ploeg, P.; Lorenz, R.; Radebaugh, J.

    2009-09-01

    Titan's equatorial dunes, observed in Cassini SAR, have been described as longitudinal, similar to longitudinal dunes in the Namib sand sea in southern Africa. Their "Y” junctions and the way they divert around topography are used as evidence of equatorial wind flow direction. In two instances of such diversion they exhibit overlying or crosshatched patterns in two distinct directions that have been interpreted as a transition to transverse dunes. Here we describe field observations of the Namibian dunes and these comparisons, we present images of the dunes from terrestrial SAR missions, and we discuss implications to both the Titan dunes and the wind regime that created them. Selected portions of the Namibian dunes resemble Titan's dunes in peak-to-peak distance and length. They are morphologically similar to Titan, and specific superficial analogs are common, but they also differ. For example, when Titan dunes encounter topography they either terminate abruptly, "climb” the upslope, or divert around; only the latter behavior is seen in remote sensing images of Namibia. Namib linear dunes do transition to transverse as they divert, but at considerably smaller wavelength, while at Titan the wavelengths are of the same scale. Crosshatching of similar-wavelength dunes does occur in Namibia, but not near obstacles. Many additional aeolian features that are seen at Namibia such as star dunes, serpentine ridges and scours have not been detected on Titan, although they might be below the Cassini SAR's 300-m resolution. These similarities and differences allow us to explore mechanisms of Titan dune formation, in some cases giving us clues as to what larger scale evidence to look for in SAR images. Viewed at similar resolution, they provide interesting comparisons with the Titan dunes, both in likeness and differences. A part of this work was carried out at JPL under contract with NASA.

  18. DESIGN AND ANALOG VLSI IMPLEMENTATION OF ARTIFICIAL NEURAL NETWORK

    Directory of Open Access Journals (Sweden)

    D.Yammenavar

    2011-08-01

    Full Text Available Nature has evolved highly advanced systems capable of performing complex computations, adoption andlearning using analog computations. Furthermore nature has evolved techniques to deal with impreciseanalog computations by using redundancy and massive connectivity. In this paper we are making use ofArtificial Neural Network to demonstrate the way in which the biological system processes in analogdomain.We are using 180nm CMOS VLSI technology for implementing circuits which performs arithmeticoperations and for implementing Neural Network. The arithmetic circuits presented here are based onMOS transistors operating in subthreshold region. The basic blocks of artificial neuron are multiplier,adder and neuron activation function.The functionality of designed neural network is verified for analog operations like signal amplificationand frequency multiplication. The network designed can be adopted for digital operations like AND, ORand NOT. The network realizes its functionality for the trained targets which is verified using simulationresults. The schematic, Layout design and verification of proposed Neural Network is carried out usingCadence Virtuoso tool.

  19. Analogies: Explanatory Tools in Web-Based Science Instruction

    Science.gov (United States)

    Glynn, Shawn M.; Taasoobshirazi, Gita; Fowler, Shawn

    2007-01-01

    This article helps designers of Web-based science instruction construct analogies that are as effective as those used in classrooms by exemplary science teachers. First, the authors explain what analogies are, how analogies foster learning, and what form analogies should take. Second, they discuss science teachers' use of analogies. Third, they…

  20. Advances in Analog Circuit Design 2015

    CERN Document Server

    Baschirotto, Andrea; Harpe, Pieter

    2016-01-01

    This book is based on the 18 tutorials presented during the 24th workshop on Advances in Analog Circuit Design. Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, including low-power and energy-efficient analog electronics, with specific contributions focusing on the design of efficient sensor interfaces and low-power RF systems. This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development. ·         Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; ·         Presents material in a tutorial-based format; ·         Includes coverage of high-performance analog-to-digital and digital to analog converters, integrated circuit design in scaled technologies, and time-domain signal processing.

  1. The Quantum Human Computer (QHC) Hypothesis

    Science.gov (United States)

    Salmani-Nodoushan, Mohammad Ali

    2008-01-01

    This article attempts to suggest the existence of a human computer called Quantum Human Computer (QHC) on the basis of an analogy between human beings and computers. To date, there are two types of computers: Binary and Quantum. The former operates on the basis of binary logic where an object is said to exist in either of the two states of 1 and…

  2. Analogies in science education: contributions and challenges

    Directory of Open Access Journals (Sweden)

    Maria da Conceição Duarte

    2005-03-01

    Full Text Available An analogy is a comparison between domains of knowledge that have similarities at the levels of characteristics and relationships. Several authors highlight the importance of this tool in the teaching and learning of difficult scientific concepts. Nevertheless, some problems associated to the use of analogies have been found. This paper aims at contributing to a better understanding of the use of analogies in science education, by means of a review of the state of art regarding this matter. It will take into account its contribution to science education as well as the challenges to further research

  3. Analog to Digital Conversion in Physical Measurements

    CERN Document Server

    Kapitaniak, T; Feudel, U; Grebogi, C

    1999-01-01

    There exist measuring devices where an analog input is converted into a digital output. Such converters can have a nonlinear internal dynamics. We show how measurements with such converting devices can be understood using concepts from symbolic dynamics. Our approach is based on a nonlinear one-to-one mapping between the analog input and the digital output of the device. We analyze the Bernoulli shift and the tent map which are realized in specific analog/digital converters. Furthermore, we discuss the sources of errors that are inevitable in physical realizations of such systems and suggest methods for error reduction.

  4. Analog Ensemble Methodology: Expansion and Optimization for Renewable Energy Applications

    Science.gov (United States)

    Harding, L.; Cervone, G.; Delle Monache, L.

    2015-12-01

    Renewable energy is fundamental for sustaining and developing society. Solar and wind energy are promising sources because of their decreased environmental impact relative to conventional energy sources, improved efficiency, and increased use. A key challenge with renewable energy production is the generation of accurate renewable energy forecasts at varying spatial and temporal scales to assist utility companies in effective energy management. Specifically, this research applies the Analog Ensemble (AnEn) methodology to short-term (0-48 hour) wind speed forecasting for power generation and short-term (0-72) hour solar power measured (PM) output predictions. AnEn uses a set of past observations corresponding to the best analogs of a deterministic numerical weather prediction model to generate a probability distribution of future atmospheric states: an ensemble of analogs. Currently the AnEn methodology equally weights predictors and only handles 1D(time). We determine an optimal distribution of predictor weights based upon parameter characteristics, investigate spatial variations in the application of the methodology and develop a theory expanding the methodology into 2D. The AnEn methodology improves short-term prediction accuracy, decreases computational costs and provides uncertainty quantification allowing utility companies to manage over- or under power generation for renewable energy sources.

  5. Analysis and compensation of the effects of analog VLSI arithmetic on the LMS algorithm.

    Science.gov (United States)

    Carvajal, Gonzalo; Figueroa, Miguel; Sbarbaro, Daniel; Valenzuela, Waldo

    2011-07-01

    Analog very large scale integration implementations of neural networks can compute using a fraction of the size and power required by their digital counterparts. However, intrinsic limitations of analog hardware, such as device mismatch, charge leakage, and noise, reduce the accuracy of analog arithmetic circuits, degrading the performance of large-scale adaptive systems. In this paper, we present a detailed mathematical analysis that relates different parameters of the hardware limitations to specific effects on the convergence properties of linear perceptrons trained with the least-mean-square (LMS) algorithm. Using this analysis, we derive design guidelines and introduce simple on-chip calibration techniques to improve the accuracy of analog neural networks with a small cost in die area and power dissipation. We validate our analysis by evaluating the performance of a mixed-signal complementary metal-oxide-semiconductor implementation of a 32-input perceptron trained with LMS.

  6. Use of analogy in learning scientific concepts.

    Science.gov (United States)

    Donnelly, C M; McDaniel, M A

    1993-07-01

    Four experiments compared learning of scientific concepts as expressed in either traditional literal form or through an analogy. Comprehension of basic-level details and inferential implications was measured through multiple-choice testing. In Experiment 1, literal or analogical renditions were presented in textual form only. In Experiment 2, text was accompanied by a dynamic video. In Experiment 3, the video and text literal rendition was compared with a text-only analogical rendition. In Experiment 4, subjects read only about a familiar domain. Subjects consistently answered basic-level questions most accurately when concepts were expressed literally, but answered inferential questions most accurately when concepts were expressed analogically. Analysis of individual differences (Experiment 2) indicated that this interaction strongly characterized the conceptual learning of science novices. The results are discussed within the framework of schema induction.

  7. Identifying Solar Analogs in the Kepler Field

    Science.gov (United States)

    Buzasi, Derek L.; Lezcano, Andrew; Preston, Heather L.

    2014-06-01

    Since human beings live on a planet orbiting a G2 V star, to us perhaps the most intrinsically interesting category of stars about which planets have been discovered is solar analogs. While Kepler has observed more than 26000 targets which have effective temperatures within 100K of the Sun, many of these are not true solar analogs due to activity, surface gravity, metallicity, or other considerations. Here we combine ground-based measurements of effective temperature and metallicity with data on rotational periods and surface gravities derived from 16 quarters of Kepler observations to produce a near-complete sample of solar analogs in the Kepler field. We then compare the statistical distribution of stellar physical parameters, including activity level, for subsets of solar analogs consisting of KOIs and those with no detected exoplanets. Finally, we produce a list of potential solar twins in the Kepler field.

  8. Synthesis and Biological Activity of Philanthotoxin Analogs

    Institute of Scientific and Technical Information of China (English)

    Yong An ZHANG; Ke Zhong LIU; Deng Yuan WANG; Yu Zhu WANG; Liang Jian QU; Chang Jin ZHU

    2006-01-01

    The synthesis of four analogs of philanthotoxin is described. The preliminary bioassay showed that these compounds all had good insecticidal activities, and the compound 6a had the best killing effect.

  9. Analogy betwen dislocation creep and relativistic cosmology

    OpenAIRE

    J.A. Montemayor-Aldrete; J.D. Muñoz-Andrade; Mendoza-Allende, A.; Montemayor-Varela, A.

    2005-01-01

    A formal, physical analogy between plastic deformation, mainly dislocation creep, and Relativistic Cosmology is presented. The physical analogy between eight expressions for dislocation creep and Relativistic Cosmology have been obtained. By comparing the mathematical expressions and by using a physical analysis, two new equations have been obtained for dislocation creep. Also, four new expressions have been obtained for Relativistic Cosmology. From these four new equations, one may determine...

  10. The analogy between stereo depth and brightness.

    Science.gov (United States)

    Brookes, A; Stevens, K A

    1989-01-01

    Apparent depth in stereograms exhibits various simultaneous-contrast and induction effects analogous to those reported in the luminance domain. This behavior suggests that stereo depth, like brightness, is reconstructed, ie recovered from higher-order spatial derivatives or differences of the original signal. The extent to which depth is analogous to brightness is examined. There are similarities in terms of contrast effects but dissimilarities in terms of the lateral inhibition effects traditionally attributed to underlying spatial-differentiation operators.

  11. AMiBA Wideband Analog Correlator

    CERN Document Server

    Li, Chao-Te; Wilson, Warwick; Lin, Kai-Yang; Chen, Ming-Tang; Ho, P T P; Chen, Chung-Cheng; Han, Chih-Chiang; Oshiro, Peter; Martin-Cocher, Pierre; Chang, Chia-Hao; Chang, Shu-Hao; Altamirano, Pablo; Jiang, Homin; Chiueh, Tzi-Dar; Lien, Chun-Hsien; Wang, Huei; Wei, Ray-Ming; Yang, Chia-Hsiang; Peterson, Jeffrey B; Chang, Su-Wei; Huang, Yau-De; Hwang, Yuh-Jing; Kesteven, Michael; Koch, Patrick; Liu, Guo-Chin; Nishioka, Hiroaki; Umetsu, Keiichi; Wei, Tashun; Wu, Jiun-Huei Proty

    2010-01-01

    A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband IF distribution, backend signal processing and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.

  12. Protein Structure Prediction with Visuospatial Analogy

    Science.gov (United States)

    Davies, Jim; Glasgow, Janice; Kuo, Tony

    We show that visuospatial representations and reasoning techniques can be used as a similarity metric for analogical protein structure prediction. Our system retrieves pairs of α-helices based on contact map similarity, then transfers and adapts the structure information to an unknown helix pair, showing that similar protein contact maps predict similar 3D protein structure. The success of this method provides support for the notion that changing representations can enable similarity metrics in analogy.

  13. Analog baseband circuits for sensor systems

    OpenAIRE

    2008-01-01

    This thesis is composed of six publications and an overview of the research topic, which also summarizes the work. The research presented in this thesis focuses on research into analog baseband circuits for sensor systems. The research is divided into three different topics: the integration of analog baseband circuits into a radio receiver for sensor applications; the integration of an ΔΣ modulator A/D converter into a GSM/WCDMA radio receiver for mobile phones, and the integration of algorit...

  14. Automated Integrated Analog Filter Design Issues

    OpenAIRE

    2015-01-01

    An analysis of modern automated integrated analog circuits design methods and their use in integrated filter design is done. Current modern analog circuits automated tools are based on optimization algorithms and/or new circuit generation methods. Most automated integrated filter design methods are only suited to gmC and switched current filter topologies. Here, an algorithm for an active RC integrated filter design is proposed, that can be used in automated filter designs. The algorithm is t...

  15. Synthetic heparin-binding growth factor analogs

    Science.gov (United States)

    Pena, Louis A.; Zamora, Paul; Lin, Xinhua; Glass, John D.

    2007-01-23

    The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain that binds a heparin-binding growth factor receptor, covalently bound to a hydrophobic linker, which is in turn covalently bound to a non-signaling peptide that includes a heparin-binding domain. The synthetic heparin-binding growth factor analogs are useful as soluble biologics or as surface coatings for medical devices.

  16. Learning Domain Theories via Analogical Transfer

    Science.gov (United States)

    2007-01-01

    Shive & Weber 1982). In the linear kinematics section of the textbook used for this study ( Giancoli 1991), there are eight worked out examples...is analogous to the dynamics of linear motion” (p. 197, Giancoli 1991). This is common practice in textbooks, and analogies between domains form the...and Worked Solution All problems and worked solutions used in this work were taken from the same physics textbook ( Giancoli 1991). Problems are

  17. Analogical Learning and Automated Rule Constructions

    Institute of Scientific and Technical Information of China (English)

    周哈阳

    1991-01-01

    This paper describes some experiments of analogical learning and automated rule construction.The present investigation focuses on knowledge acquisition,learning by analyogy,and knowledge retention.The developed system initially learns from scratch,gradually acquires knowledge from its environment through trial-and-error interaction,incrementally augments its knowledge base,and analogically solves new tasks in a more efficient and direct manner.

  18. Cloud computing assessing the risks

    CERN Document Server

    Carstensen, Jared; Golden, Bernard

    2012-01-01

    Cloud Computing: Assessing the risks answers these questions and many more. Using jargon-free language and relevant examples, analogies and diagrams, it is an up-to-date, clear and comprehensive guide the security, governance, risk, and compliance elements of Cloud Computing.

  19. Development of analogical problem-solving skill.

    Science.gov (United States)

    Holyoak, K J; Junn, E N; Billman, D O

    1984-12-01

    3 experiments were performed to assess children's ability to solve a problem by analogy to a superficially dissimilar situation. Preschoolers and fifth and sixth graders were asked to solve a problem that allowed multiple solutions. Some subjects were first read a story that included an analogous problem and its solution. When the mapping between the relations involved in the corresponding solutions was relatively simple, and the corresponding instruments were perceptually and functionally similar, even preschoolers were able to use the analogy to derive a solution to the transfer problem (Experiment 1). Furthermore, salient similarity of the instruments was neither sufficient (Experiment 2) nor necessary (Experiment 3) for success by preschool subjects. When the story analog mapped well onto the transfer problem, 4-year-olds were often able to generate a solution that required transformation of an object with little perceptual or semantic similarity to the instrument used in the base analog (Experiment 3). The older children used analogies in a manner qualitatively similar to that observed in comparable studies with adults (Experiment 1), whereas the younger children exhibited different limitations.

  20. Analog modelling of obduction processes

    Science.gov (United States)

    Agard, P.; Zuo, X.; Funiciello, F.; Bellahsen, N.; Faccenna, C.; Savva, D.

    2012-04-01

    Obduction corresponds to one of plate tectonics oddities, whereby dense, oceanic rocks (ophiolites) are presumably 'thrust' on top of light, continental ones, as for the short-lived, almost synchronous Peri-Arabic obduction (which took place along thousands of km from Turkey to Oman in c. 5-10 Ma). Analog modelling experiments were performed to study the mechanisms of obduction initiation and test various triggering hypotheses (i.e., plate acceleration, slab hitting the 660 km discontinuity, ridge subduction; Agard et al., 2007). The experimental setup comprises (1) an upper mantle, modelled as a low-viscosity transparent Newtonian glucose syrup filling a rigid Plexiglas tank and (2) high-viscosity silicone plates (Rhodrosil Gomme with PDMS iron fillers to reproduce densities of continental or oceanic plates), located at the centre of the tank above the syrup to simulate the subducting and the overriding plates - and avoid friction on the sides of the tank. Convergence is simulated by pushing on a piston at one end of the model with velocities comparable to those of plate tectonics (i.e., in the range 1-10 cm/yr). The reference set-up includes, from one end to the other (~60 cm): (i) the piston, (ii) a continental margin containing a transition zone to the adjacent oceanic plate, (iii) a weakness zone with variable resistance and dip (W), (iv) an oceanic plate - with or without a spreading ridge, (v) a subduction zone (S) dipping away from the piston and (vi) an upper, active continental margin, below which the oceanic plate is being subducted at the start of the experiment (as is known to have been the case in Oman). Several configurations were tested and over thirty different parametric tests were performed. Special emphasis was placed on comparing different types of weakness zone (W) and the extent of mechanical coupling across them, particularly when plates were accelerated. Displacements, together with along-strike and across-strike internal deformation in all

  1. Multimode lasers as analogs of complex biological systems (a survey)

    Science.gov (United States)

    Danilov, O. B.; Rosanov, N. N.; Solov'ev, N. A.; Soms, L. N.

    2016-04-01

    Simulating the activity of complex biological systems, in particular, the human brain, is a topical problem the solution of which is necessary both for understanding their functioning and for developing new classes of computational system based on operating principles of the brain. Some features and analogies that can be found in the operation of laser systems and brain and used for developing new generation computational systems are discussed. The appropriateness of such analogies is justified by the fact that both laser systems and the brain are open (interacting with the environment) dissipative spatially distributed nonlinear systems. Therefore, laser optical systems and, in particular, systems with dissipative optical solitons offer an opportunity to experimentally and theoretically model some important cognitive brain functions. One of particularities of the brain operation is the ability to manipulate images. Proceeding from this, in this work, problems related to generation and amplification with laser of spatial structures (images), as well as to amplification of signals coming to it from outside are discussed.

  2. A New Sum Analogous to Gauss Sums and Its Fourth Power Mean

    Directory of Open Access Journals (Sweden)

    Shaofeng Ru

    2014-01-01

    Full Text Available The main purpose of this paper is to use the analytic methods and the properties of Gauss sums to study the computational problem of one kind of new sum analogous to Gauss sums and give an interesting fourth power mean and a sharp upper bound estimate for it.

  3. Anti-Plasmodium activity of ceramide analogs

    Directory of Open Access Journals (Sweden)

    Gatt Shimon

    2004-12-01

    Full Text Available Abstract Background Sphingolipids are key molecules regulating many essential functions in eukaryotic cells and ceramide plays a central role in sphingolipid metabolism. A sphingolipid metabolism occurs in the intraerythrocytic stages of Plasmodium falciparum and is associated with essential biological processes. It constitutes an attractive and potential target for the development of new antimalarial drugs. Methods The anti-Plasmodium activity of a series of ceramide analogs containing different linkages (amide, methylene or thiourea linkages between the fatty acid part of ceramide and the sphingoid core was investigated in culture and compared to the sphingolipid analog PPMP (d,1-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol. This analog is known to inhibit the parasite sphingomyelin synthase activity and block parasite development by preventing the formation of the tubovesicular network that extends from the parasitophorous vacuole to the red cell membrane and delivers essential extracellular nutrients to the parasite. Results Analogs containing methylene linkage showed a considerably higher anti-Plasmodium activity (IC50 in the low nanomolar range than PPMP and their counterparts with a natural amide linkage (IC50 in the micromolar range. The methylene analogs blocked irreversibly P. falciparum development leading to parasite eradication in contrast to PPMP whose effect is cytostatic. A high sensitivity of action towards the parasite was observed when compared to their effect on the human MRC-5 cell growth. The toxicity towards parasites did not correlate with the inhibition by methylene analogs of the parasite sphingomyelin synthase activity and the tubovesicular network formation, indicating that this enzyme is not their primary target. Conclusions It has been shown that ceramide analogs were potent inhibitors of P. falciparum growth in culture. Interestingly, the nature of the linkage between the fatty acid part and the

  4. The future of vitamin D analogs

    Directory of Open Access Journals (Sweden)

    Carlien eLeyssens

    2014-04-01

    Full Text Available The active form of vitamin D3, 1,25-dihydroxyvitamin D3, is a major regulator of bone and calcium homeostasis. In addition, this hormone also inhibits the proliferation and stimulates the differentiation of normal as well as malignant cells. Supraphysiological doses of 1,25-dihydroxyvitamin D3 are required to reduce cancer cell proliferation. However, these doses will lead in vivo to calcemic side effects such as hypercalcemia and hypercalciuria. During the last 25 years, many structural analogs of 1,25-dihydroxyvitamin D3 have been synthesized by the introduction of chemical modifications in the A-ring, central CD-ring region or side chain of 1,25-dihydroxyvitamin D3 in the hope to find molecules with a clear dissociation between the beneficial antiproliferative effects and adverse calcemic side effects. One example of such an analog with a good dissociation ratio is calcipotriol (DaivonexR, which is clinically used to treat the hyperproliferative skin disease psoriasis. Other vitamin D analogs were clinically approved for the treatment of osteoporosis or secondary hyperparathyroidism. No vitamin D analog is currently used in the clinic for the treatment of cancer although several analogs have been shown to be potent drugs in animal models of cancer. Omics studies as well as in vitro cell biological experiments unraveled basic mechanisms involved in the antineoplastic effects of vitamin D and its analogs. 1,25-dihydroxyvitamin D3 and analogs act in a cell type- and tissue-specific manner. Moreover, a blockade in the transition of the G0/1 towards S phase of the cell cycle, induction of apoptosis, inhibition of migration and invasion of tumor cells together with effects on angiogenesis and inflammation have been implicated in the pleiotropic effects of 1,25-dihydroxyvitamin D3 and its analogs. In this review we will give an overview of the action of vitamin D analogs in tumor cells and look forward how these compounds could be introduced in the

  5. Analog forecasting with dynamics-adapted kernels

    Science.gov (United States)

    Zhao, Zhizhen; Giannakis, Dimitrios

    2016-09-01

    Analog forecasting is a nonparametric technique introduced by Lorenz in 1969 which predicts the evolution of states of a dynamical system (or observables defined on the states) by following the evolution of the sample in a historical record of observations which most closely resembles the current initial data. Here, we introduce a suite of forecasting methods which improve traditional analog forecasting by combining ideas from kernel methods developed in harmonic analysis and machine learning and state-space reconstruction for dynamical systems. A key ingredient of our approach is to replace single-analog forecasting with weighted ensembles of analogs constructed using local similarity kernels. The kernels used here employ a number of dynamics-dependent features designed to improve forecast skill, including Takens’ delay-coordinate maps (to recover information in the initial data lost through partial observations) and a directional dependence on the dynamical vector field generating the data. Mathematically, our approach is closely related to kernel methods for out-of-sample extension of functions, and we discuss alternative strategies based on the Nyström method and the multiscale Laplacian pyramids technique. We illustrate these techniques in applications to forecasting in a low-order deterministic model for atmospheric dynamics with chaotic metastability, and interannual-scale forecasting in the North Pacific sector of a comprehensive climate model. We find that forecasts based on kernel-weighted ensembles have significantly higher skill than the conventional approach following a single analog.

  6. Analogy, higher order thinking, and education.

    Science.gov (United States)

    Richland, Lindsey Engle; Simms, Nina

    2015-01-01

    Analogical reasoning, the ability to understand phenomena as systems of structured relationships that can be aligned, compared, and mapped together, plays a fundamental role in the technology rich, increasingly globalized educational climate of the 21st century. Flexible, conceptual thinking is prioritized in this view of education, and schools are emphasizing 'higher order thinking', rather than memorization of a cannon of key topics. The lack of a cognitively grounded definition for higher order thinking, however, has led to a field of research and practice with little coherence across domains or connection to the large body of cognitive science research on thinking. We review literature on analogy and disciplinary higher order thinking to propose that relational reasoning can be productively considered the cognitive underpinning of higher order thinking. We highlight the utility of this framework for developing insights into practice through a review of mathematics, science, and history educational contexts. In these disciplines, analogy is essential to developing expert-like disciplinary knowledge in which concepts are understood to be systems of relationships that can be connected and flexibly manipulated. At the same time, analogies in education require explicit support to ensure that learners notice the relevance of relational thinking, have adequate processing resources available to mentally hold and manipulate relations, and are able to recognize both the similarities and differences when drawing analogies between systems of relationships.

  7. Neurotoxic Alkaloids: Saxitoxin and Its Analogs

    Directory of Open Access Journals (Sweden)

    Troco K. Mihali

    2010-07-01

    Full Text Available Saxitoxin (STX and its 57 analogs are a broad group of natural neurotoxic alkaloids, commonly known as the paralytic shellfish toxins (PSTs. PSTs are the causative agents of paralytic shellfish poisoning (PSP and are mostly associated with marine dinoflagellates (eukaryotes and freshwater cyanobacteria (prokaryotes, which form extensive blooms around the world. PST producing dinoflagellates belong to the genera Alexandrium, Gymnodinium and Pyrodinium whilst production has been identified in several cyanobacterial genera including Anabaena, Cylindrospermopsis, Aphanizomenon Planktothrix and Lyngbya. STX and its analogs can be structurally classified into several classes such as non-sulfated, mono-sulfated, di-sulfated, decarbamoylated and the recently discovered hydrophobic analogs—each with varying levels of toxicity. Biotransformation of the PSTs into other PST analogs has been identified within marine invertebrates, humans and bacteria. An improved understanding of PST transformation into less toxic analogs and degradation, both chemically or enzymatically, will be important for the development of methods for the detoxification of contaminated water supplies and of shellfish destined for consumption. Some PSTs also have demonstrated pharmaceutical potential as a long-term anesthetic in the treatment of anal fissures and for chronic tension-type headache. The recent elucidation of the saxitoxin biosynthetic gene cluster in cyanobacteria and the identification of new PST analogs will present opportunities to further explore the pharmaceutical potential of these intriguing alkaloids.

  8. Magnetic activity of seismic solar analogs

    CERN Document Server

    Salabert, D

    2016-01-01

    We present our latest results on the solar-stellar connection by studying 18 solar analogs that we identified among the Kepler seismic sample (Salabert et al., 2016a). We measured their magnetic activity properties using observations collected by the Kepler satellite and the ground-based, high-resolution Hermes spectrograph. The photospheric (Sph) and chromospheric (S) magnetic activity proxies of these seismic solar analogs are compared in relation to solar activity. We show that the activity of the Sun is actually comparable to the activity of the seismic solar analogs. Furthermore, we report on the discovery of temporal variability in the acoustic frequencies of the young (1 Gyr-old) solar analog KIC10644253 with a modulation of about 1.5 years, which agrees with the derived photospheric activity (Salabert et al., 2016b). It could actually be the signature of the short-period modulation, or quasi-biennal oscillation, of its magnetic activity as observed in the Sun and the 1-Gyr-old solar analog HD30495. In...

  9. NaturAnalogs for the Unsaturated Zone

    Energy Technology Data Exchange (ETDEWEB)

    A. Simmons; A. Unger; M. Murrell

    2000-03-08

    The purpose of this Analysis/Model Report (AMR) is to document natural and anthropogenic (human-induced) analog sites and processes that are applicable to flow and transport processes expected to occur at the potential Yucca Mountain repository in order to build increased confidence in modeling processes of Unsaturated Zone (UZ) flow and transport. This AMR was prepared in accordance with ''AMR Development Plan for U0135, Natural Analogs for the UZ'' (CRWMS 1999a). Knowledge from analog sites and processes is used as corroborating information to test and build confidence in flow and transport models of Yucca Mountain, Nevada. This AMR supports the Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR) and the Yucca Mountain Site Description. The objectives of this AMR are to test and build confidence in the representation of UZ processes in numerical models utilized in the UZ Flow and Transport Model. This is accomplished by: (1) applying data from Boxy Canyon, Idaho in simulations of UZ flow using the same methodologies incorporated in the Yucca Mountain UZ Flow and Transport Model to assess the fracture-matrix interaction conceptual model; (2) Providing a preliminary basis for analysis of radionuclide transport at Pena Blanca, Mexico as an analog of radionuclide transport at Yucca Mountain; and (3) Synthesizing existing information from natural analog studies to provide corroborating evidence for representation of ambient and thermally coupled UZ flow and transport processes in the UZ Model.

  10. Not All Analogies Are Created Equal: Associative and Categorical Analogy Processing following Brain Damage

    Science.gov (United States)

    Schmidt, Gwenda L.; Cardillo, Eileen R.; Kranjec, Alexander; Lehet, Matthew; Widick, Page; Chatterjee, Anjan

    2012-01-01

    Current research on analogy processing assumes that different conceptual relations are treated similarly. However, just as words and concepts are related in distinct ways, different kinds of analogies may employ distinct types of relationships. An important distinction in how words are related is the difference between associative (dog-bone) and…

  11. Analogy-Enhanced Instruction: Effects on Reasoning Skills in Science

    Science.gov (United States)

    Remigio, Krisette B.; Yangco, Rosanelia T.; Espinosa, Allen A.

    2014-01-01

    The study examined the reasoning skills of first year high school students after learning general science concepts through analogies. Two intact heterogeneous sections were randomly assigned to Analogy-Enhanced Instruction (AEI) group and Non Analogy-Enhanced (NAEI) group. Various analogies were incorporated in the lessons of the AEI group for…

  12. Value and Limitations of Analogs in Teaching Mathematics.

    Science.gov (United States)

    Halford, Graeme S.; Boulton-Lewis, Gillian M.

    Analogical reasoning is frequently used in acquisition of mathematical concepts. Concrete representations used to teach mathematics are essentially analogs of mathematical concepts, and it is argued that analogies enter into mathematical concept acquisition in numerous other ways as well. According to Gentner's theory, analogies entail a…

  13. Analog Forecasting with Dynamics-Adapted Kernels

    CERN Document Server

    Zhao, Zhizhen

    2014-01-01

    Analog forecasting is a non-parametric technique introduced by Lorenz in 1969 which predicts the evolution of states of a dynamical system (or observables defined on the states) by following the evolution of the sample in a historical record of observations which most closely resembles the current initial data. Here, we introduce a suite of forecasting methods which improve traditional analog forecasting by combining ideas from state-space reconstruction for dynamical systems and kernel methods developed in harmonic analysis and machine learning. The first improvement is to augment the dimension of the initial data using Takens' delay-coordinate maps to recover information in the initial data lost through partial observations. Then, instead of using Euclidean distances between the states, weighted ensembles of analogs are constructed according to similarity kernels in delay-coordinate space, featuring an explicit dependence on the dynamical vector field generating the data. The eigenvalues and eigenfunctions ...

  14. On Lovelock analogs of the Riemann tensor

    Energy Technology Data Exchange (ETDEWEB)

    Camanho, Xian O. [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik, Golm (Germany); Dadhich, Naresh [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); Inter-University Centre for Astronomy and Astrophysics, Pune (India)

    2016-03-15

    It is possible to define an analog of the Riemann tensor for Nth order Lovelock gravity, its characterizing property being that the trace of its Bianchi derivative yields the corresponding analog of the Einstein tensor. Interestingly there exist two parallel but distinct such analogs and the main purpose of this note is to reconcile both formulations. In addition we will introduce a simple tensor identity and use it to show that any pure Lovelock vacuum in odd d = 2N + 1 dimensions is Lovelock flat, i.e. any vacuum solution of the theory has vanishing Lovelock-Riemann tensor. Further, in the presence of cosmological constant it is the Lovelock-Weyl tensor that vanishes. (orig.)

  15. Formal analogies in physics teacher education

    DEFF Research Database (Denmark)

    Avelar Sotomaior Karam, Ricardo; Ricardo, Elio

    2012-01-01

    the relevance of the subject, formal analogies are rarely systematically approached in physics education. In order to discuss this issue with pre-service physics teachers, we planned a lecture and designed a questionnaire with the goal of encouraging them to think about some “coincidences” in well known......Reasoning by similarities, especially the ones associated with formal aspects, is one of the most valuable sources for the development of physical theories. The essential role of formal analogies in science can be highlighted by the fact that several equations for different physical situations have...... the exact same appearance. Coulomb’s law’s similarity with Newton’s, Maxwell’s application of fluid theory to electromagnetism and Hamilton’s optical mechanical analogy are some among many other examples. These cases illustrate the power of mathematics in providing unifying structures for physics. Despite...

  16. Analog Module Placement Design Using Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This paper presents a novel genetic algorithm for analog module placement based on ageneralization of the two-dimensional bin packing problem. The genetic encoding and operators assure that allproblem constraints are always satisfied. Thus the potential problems of adding penalty terms to the costfunction are eliminated so that the search configuration space is drastically decreased. The dedicated costfunction is based on the special requirements of analog integrated circuits. A fractional factorial experimentwas conducted using an orthogonal array to study the algorithm parameters. A meta GA was applied todetermine the optimal parameter values. The algorithm was tested with several local benchmark circuits. Theexperimental results show that the algorithm has better performance than the simulated annealing approachwith satisfactory results comparable to manual placement. This study demonstrates the effectiveness of thegenetic algorithm in the analog module placement problem. The algorithm has been successfully used in alayout synthesis tool.

  17. Electronic devices for analog signal processing

    CERN Document Server

    Rybin, Yu K

    2012-01-01

    Electronic Devices for Analog Signal Processing is intended for engineers and post graduates and considers electronic devices applied to process analog signals in instrument making, automation, measurements, and other branches of technology. They perform various transformations of electrical signals: scaling, integration, logarithming, etc. The need in their deeper study is caused, on the one hand, by the extension of the forms of the input signal and increasing accuracy and performance of such devices, and on the other hand, new devices constantly emerge and are already widely used in practice, but no information about them are written in books on electronics. The basic approach of presenting the material in Electronic Devices for Analog Signal Processing can be formulated as follows: the study with help from self-education. While divided into seven chapters, each chapter contains theoretical material, examples of practical problems, questions and tests. The most difficult questions are marked by a diamon...

  18. Words, Concepts, and the Geometry of Analogy

    Directory of Open Access Journals (Sweden)

    Stephen McGregor

    2016-08-01

    Full Text Available This paper presents a geometric approach to the problem of modelling the relationship between words and concepts, focusing in particular on analogical phenomena in language and cognition. Grounded in recent theories regarding geometric conceptual spaces, we begin with an analysis of existing static distributional semantic models and move on to an exploration of a dynamic approach to using high dimensional spaces of word meaning to project subspaces where analogies can potentially be solved in an online, contextualised way. The crucial element of this analysis is the positioning of statistics in a geometric environment replete with opportunities for interpretation.

  19. Fungitoxicity of chemical analogs with heartwood toxins.

    Science.gov (United States)

    Grohs, B M; Kunz, B

    1998-07-01

    Trans-stilbene and tropolone as chemical analogs with naturally occurring fungitoxic heartwood compounds were studied with respect to their fungitoxic potency. While stilbene showed no fungitoxic activity towards the fungi Aureobasidium pullulans var. melanogenum, Penicillium glabrum, and Trichoderma harzianum in the concentrations tested, the minimal inhibiting concentration of tropolone was 10(-3) M for Penicillium glabrum and Trichoderma harzianum, and 10(-5) M for Aureobasidium pullulans var. melanogenum. In all cases, the effect of tropolone was a fungistatic one. Using chemical analogs for assessing the chemical basis of the fungitoxicity of tropolone, this substance proved to be the only compound tested which possesses fungitoxic properties.

  20. Automated Integrated Analog Filter Design Issues

    Directory of Open Access Journals (Sweden)

    Karolis Kiela

    2015-07-01

    Full Text Available An analysis of modern automated integrated analog circuits design methods and their use in integrated filter design is done. Current modern analog circuits automated tools are based on optimization algorithms and/or new circuit generation methods. Most automated integrated filter design methods are only suited to gmC and switched current filter topologies. Here, an algorithm for an active RC integrated filter design is proposed, that can be used in automated filter designs. The algorithm is tested by designing an integrated active RC filter in a 65 nm CMOS technology.

  1. Synthetic heparin-binding factor analogs

    Science.gov (United States)

    Pena, Louis A.; Zamora, Paul O.; Lin, Xinhua; Glass, John D.

    2010-04-20

    The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain, and preferably two peptide chains branched from a dipeptide branch moiety composed of two trifunctional amino acid residues, which peptide chain or chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a linker, which may be a hydrophobic linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  2. Analysis of Recurrent Analog Neural Networks

    Directory of Open Access Journals (Sweden)

    Z. Raida

    1998-06-01

    Full Text Available In this paper, an original rigorous analysis of recurrent analog neural networks, which are built from opamp neurons, is presented. The analysis, which comes from the approximate model of the operational amplifier, reveals causes of possible non-stable states and enables to determine convergence properties of the network. Results of the analysis are discussed in order to enable development of original robust and fast analog networks. In the analysis, the special attention is turned to the examination of the influence of real circuit elements and of the statistical parameters of processed signals to the parameters of the network.

  3. Analog circuit design for communication SOC

    CERN Document Server

    Tu, Steve Hung-Lung

    2012-01-01

    This e-book provides several state-of-the-art analog circuit design techniques. It presents both empirical and theoretical materials for system-on-a-chip (SOC) circuit design. Fundamental communication concepts are used to explain a variety of topics including data conversion (ADC, DAC, S-? oversampling data converters), clock data recovery, phase-locked loops for system timing synthesis, supply voltage regulation, power amplifier design, and mixer design. This is an excellent reference book for both circuit designers and researchers who are interested in the field of design of analog communic

  4. Analogies between a Meniscus and a Cantilever

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-Lin

    2009-01-01

    Systematic and quantitative analyses of exact analogies between a meniscus and an elastica are performed. It is shown that the two governing equations take the same style after coordinate translation and scale transformation. The morphologies of the liquid bridge and the cantilever are calculated in terms of elliptic integrations, which can be reduced to the same shape,after converting the boundary conditions. The present analyses can make us grasp the nature of this physical phenomenon deeply and show some inspiration for designing the analogy experiments. Moreover, the calculated results are helpful to engineering applications, such as design and fabrication of MEMS, and micro-manipulations in micro/nano- technology.

  5. ENHANCING THE SYMBOLIC ANALYSIS OF ANALOG CIRCUITS

    Directory of Open Access Journals (Sweden)

    E. Tlelo-Cuautle

    2005-08-01

    Full Text Available A new symbollc-method is introduced to enhance the calculation of symbolic expressions of analog circults. First, the analog circuit is transformed to a nullor equivalent circuit. Second, a new method is introduced to the formulation of a compact system of equations (CSES. Third, a new method is introduced to the solution of theCSES, by avoiding multiplications by zero to Improve the evaluation of determlnants. Flnally, two eXamples are given to show the usefulness of the proposed methods to calculate fully symbolic transfer functions.

  6. An Optical Analog of a Black Holes

    CERN Document Server

    Royston, A; Royston, Andrew; Gass, Richard

    2002-01-01

    Using media with extremely low group velocities one can create an optical analog of a curved space-time. Leonhardt and Piwnicki have proposed that a vortex flow will act as an optical black hole. We show that although the Leonhardt - Piwnicki flow has an orbit of no return and an infinite red-shift surface, it is not a true black hole since it lacks a null hypersurface. However a radial flow will produce a true optical black hole that has a Hawking temperature and obeys the first law of black hole mechanics. By combining the Leonhardt - Piwnicki flow with a radial flow we obtain the analog of the Kerr black hole.

  7. COMPUTERS IN INFORMATION SCIENCES, VOLUME 2

    Science.gov (United States)

    The unclassified and unlimited bibliography compiles references dealing specifically with the role of computers in information sciences . The volume contains 239 annotated references grouped under three major headings: Artificial and Programming Languages, Computer Processing of Analog Data, and Computer Processing of Digital Data. The references

  8. An analog retina model for detecting dim moving objects against a bright moving background

    Science.gov (United States)

    Searfus, R. M.; Colvin, M. E.; Eeckman, F. H.; Teeters, J. L.; Axelrod, T. S.

    1991-01-01

    We are interested in applications that require the ability to track a dim target against a bright, moving background. Since the target signal will be less than or comparable to the variations in the background signal intensity, sophisticated techniques must be employed to detect the target. We present an analog retina model that adapts to the motion of the background in order to enhance targets that have a velocity difference with respect to the background. Computer simulation results and our preliminary concept of an analog 'Z' focal plane implementation are also presented.

  9. Analogies and Reconstruction of Mathematical Knowledge.

    Science.gov (United States)

    Fast, Gerald R.

    An investigation was conducted to determine the effectiveness of utilizing analogies to effect conceptual change in mathematics. Forty-one high school seniors participated in a knowledge reconstruction process regarding their beliefs about everyday probability situations such as sports events or lotteries. These mathematics students were given…

  10. Analogy and mathematical reasoning : a survey

    OpenAIRE

    Miller, C. D. F.

    1983-01-01

    We survey the literature of Artificial Intelligence, and other related work, pertaining to the modelling of mathematical reasoning and its relationship with the use of analogy. In particular, we discuss the contribution of Lenat's program AM to models of mathematical discovery and concept-formation. We consider the use of similarity measures to structure a knowledge space and their role in concept acquisition.

  11. Analog circuit design designing waveform processing circuits

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    The fourth volume in the set Designing Waveform-Processing Circuits builds on the previous 3 volumes and presents a variety of analog non-amplifier circuits, including voltage references, current sources, filters, hysteresis switches and oscilloscope trigger and sweep circuitry, function generation, absolute-value circuits, and peak detectors.

  12. An iconic, analogical approach to grammaticalization

    NARCIS (Netherlands)

    Fischer, O.; Conradie, C.J.; Johl, R.; Beukes, M.; Fischer, O.; Ljungberg, C.

    2010-01-01

    This paper addresses a number of problems connected with the ‘apparatus’ used in grammaticalization theory. It will be argued that we get a better grip on what happens in processes of grammaticalization (and its ‘opposite’, lexicalization) if the process is viewed in terms of analogical processes, w

  13. CMOS circuits for analog signal processing

    NARCIS (Netherlands)

    Wallinga, Hans

    1988-01-01

    Design choices in CMOS analog signal processing circuits are presented. Special attention is focussed on continuous-time filter technologies. The basics of MOSFET-C continuous-time filters and CMOS Square Law Circuits are explained at the hand of a graphical MOST characteristics representation.

  14. Analog Acoustic Expression in Speech Communication

    Science.gov (United States)

    Shintel, Hadas; Nusbaum, Howard C.; Okrent, Arika

    2006-01-01

    We present the first experimental evidence of a phenomenon in speech communication we call "analog acoustic expression." Speech is generally thought of as conveying information in two distinct ways: discrete linguistic-symbolic units such as words and sentences represent linguistic meaning, and continuous prosodic forms convey information about…

  15. Invention through Form and Function Analogy

    Science.gov (United States)

    Rule, Audrey C.

    2015-01-01

    "Invention through Form and Function Analogy" is an invention book for teachers and other leaders working with youth who are involving students in the invention process. The book consists of an introduction and set of nine learning cycle formatted lessons for teaching the principles of invention through the science and engineering design…

  16. C4913 ANALOGE OG DIGITALE FILTRE

    DEFF Research Database (Denmark)

    Gaunholt, Hans

    1996-01-01

    Theese lecture notes treats the fundamental theory and the most commonly used design methods for passive- active and digital filters with special emphasis on microelectronic realizations. The lecture notes covers 75% of the material taught in the course C4913 Analog and Digital Filters...

  17. The GMO-Nanotech (Dis)Analogy?

    Science.gov (United States)

    Sandler, Ronald; Kay, W. D.

    2006-01-01

    The genetically-modified-organism (GMO) experience has been prominent in motivating science, industry, and regulatory communities to address the social and ethical dimensions of nanotechnology. However, there are some significant problems with the GMO-nanotech analogy. First, it overstates the likelihood of a GMO-like backlash against…

  18. Analog of Superradiance effect in BEC

    CERN Document Server

    Basak, S

    2005-01-01

    We investigate the scattering of phase oscillation of Bose-Einstein Condensate by a 'draining of bathtub' type fluid motion. We derive a relation between the reflection and transmission coefficients which exhibits existence of analog of 'Superradiance effect' in BEC vortex with sink.

  19. Classical Analog of Electromagnetically Induced Transparency

    CERN Document Server

    Alzar, C L G; Nussenzveig, P

    2002-01-01

    We present a classical analog for Electromagnetically Induced Transparency (EIT). In a system of just two coupled harmonic oscillators subject to a harmonic driving force we can reproduce the phenomenology observed in EIT. We describe a simple experiment performed with two linearly coupled RLC circuits which can be taught in an undergraduate laboratory class.

  20. Analogy between thermal convective and magnetohydrodynamic instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Valdmanis, Ya.Ya.; Kukainis, O.A.

    1977-01-01

    An examination is made of the analogy between thermo-convective instability and instability produced by various electromagnetic forces both in steady and alternating thermal and electromagnetic fields. An example is given for calculating an assumed bubble instability which could occur in an alternating magnetic field. 17 references.

  1. An analysis of structure fitting and bioactivity between sex pheromone of cotton bollworm, Helicoverpa armigera (H(u)bner) and its fluorinated analogs

    Institute of Scientific and Technical Information of China (English)

    KAN Wei; ZHANG Zhongning; YANG Xinling; FANG Yuling; XIAO Chun

    2005-01-01

    A study on the structure-activty relationship between (Z)-hexadec-9-enal (Z-9-16:Ald) and its analog was conducted by comparing the structures of the sex pheromone of cotton bollworm, Helicoverpa armigera (Hübner) with its fluorinated analog using computer molecular fitting. It is demonstrated that the structure of analog substituting for hydrogen atom on the terminal carbon atom is similar to Z-9-16:Ald. The EAG result showed that there is no significant difference in activities between Z-9-16:Ald and its fluorinated analog synthesized.

  2. Interfacing the Analog Camera with FPGA Board for Real-time Video Acquisition

    Directory of Open Access Journals (Sweden)

    Sanjay Singh

    2014-03-01

    Full Text Available Advances in FPGA technology have dramatically increased the use of FPGAs for computer vision applications. The primary task for development of such FPGAs based systems is the interfacing of the analog camera with FPGA board. This paper describes the design and implementation of camera interface module required for connecting analog camera with Xilinx ML510 (Virtex–5 FXT FPGA board having no video input port. Digilent VDEC1 video daughter card is used for digitizing the analog video into digital form. The necessary control logics for video acquisition and video display are designed using VHDL and Verilog, simulated in ModelSim, and synthesized using Xilinx ISE 12.1. Designed and implemented interfaces provide the real-time video acquisition and display.

  3. An Open-Source Tool Set Enabling Analog-Digital-Software Co-Design

    Directory of Open Access Journals (Sweden)

    Michelle Collins

    2016-02-01

    Full Text Available This paper presents an analog-digital hardware-software co-design environment for simulating and programming reconfigurable systems. The tool simulates, designs, as well as enables experimental measurements after compiling to configurable systems in the same integrated design tool framework. High level software in Scilab/Xcos (open-source programs similar to MATLAB/Simulink that converts the high-level block description by the user to blif format (sci2blif, which acts as an input to the modified VPR tool, including the code v p r 2 s w c s , encoding the specific platform through specific architecture files, resulting in a targetable switch list on the resulting configurable analog–digital system. The resulting tool uses an analog and mixed-signal library of components, enabling users and future researchers access to the basic analog operations/computations that are possible.

  4. Modeling selective attention using a neuromorphic analog VLSI device.

    Science.gov (United States)

    Indiveri, G

    2000-12-01

    Attentional mechanisms are required to overcome the problem of flooding a limited processing capacity system with information. They are present in biological sensory systems and can be a useful engineering tool for artificial visual systems. In this article we present a hardware model of a selective attention mechanism implemented on a very large-scale integration (VLSI) chip, using analog neuromorphic circuits. The chip exploits a spike-based representation to receive, process, and transmit signals. It can be used as a transceiver module for building multichip neuromorphic vision systems. We describe the circuits that carry out the main processing stages of the selective attention mechanism and provide experimental data for each circuit. We demonstrate the expected behavior of the model at the system level by stimulating the chip with both artificially generated control signals and signals obtained from a saliency map, computed from an image containing several salient features.

  5. Analog Design for Digital Deployment of a Serious Leadership Game

    Science.gov (United States)

    Maxwell, Nicholas; Lang, Tristan; Herman, Jeffrey L.; Phares, Richard

    2012-01-01

    This paper presents the design, development, and user testing of a leadership development simulation. The authors share lessons learned from using a design process for a board game to allow for quick and inexpensive revision cycles during the development of a serious leadership development game. The goal of this leadership simulation is to accelerate the development of leadership capacity in high-potential mid-level managers (GS-15 level) in a federal government agency. Simulation design included a mixed-method needs analysis, using both quantitative and qualitative approaches to determine organizational leadership needs. Eight design iterations were conducted, including three user testing phases. Three re-design iterations followed initial development, enabling game testing as part of comprehensive instructional events. Subsequent design, development and testing processes targeted digital application to a computer- and tablet-based environment. Recommendations include pros and cons of development and learner testing of an initial analog simulation prior to full digital simulation development.

  6. Understanding Young Exoplanet Analogs with WISE

    Science.gov (United States)

    Rice, Emily

    We propose to tackle outstanding questions about the fundamental properties of young brown dwarfs, which are atmospheric analogs to massive gas giant exoplanets, using public archive data from the Wide-field Infrared Survey Explorer (WISE) combined with our extensive dataset of optical and near-infrared observations, including spectra, proper motions, and parallaxes. Using WISE data we will construct color-color diagrams, color- magnitude diagrams, and spectral energy distributions for our sample of candidate young brown dwarfs. We will fully characterize the spectral properties of the candidates and evaluate their membership in nearby young moving groups in order to obtain independent age estimates. The practical outcomes of this project will allow the research community to use observed colors and spectra to reliably constrain the properties - including effective temperature, gravity, and dust/cloud properties - of both brown dwarfs and gas giant exoplanets. We will also search for new young brown dwarfs in the WISE archive using colors and proper motions. The expanded sample of young brown dwarfs will be used to create a self-contained feedback loop to identify and address the shortcomings of cool atmosphere models and low-mass evolutionary tracks, both of which are already being used to infer the properties of massive exoplanets. Disentangling the effects of physical parameters on the observed properties of young brown dwarfs is directly relevant to studies of exoplanets. Direct observations of exoplanets are currently very limited, and young brown dwarfs are the laboratories in which we can solve existing problems before the onslaught of new observations from instruments capable of directly imaging exoplanets, including the Gemini Planet Imager, Project 1640 at the Palomar Observatory, SPHERE on the VLT, and the James Webb Space Telescope. This project addresses the goal of the NASA Science Mission Directorate to discover how the universe works; in particular

  7. Playing with a double-edged sword: Analogies in biochemistry

    Science.gov (United States)

    Orgill, Marykay

    Analogy pervades our everyday reasoning. No situation we encounter is exactly like a situation we have encountered previously, and our ability to learn and survive in the world is based on our ability to find similarities between past and present situations and use the knowledge we have gained from past situations to manage current situations. Analogies can be powerful teaching tools because they can make new material intelligible to students by comparing it to material that is already familiar. It is clear, though, that not all analogies are good and that not all good analogies are useful to all students. In this study, I have used textbook analysis, classroom observations, student interviews and instructor interviews to determine the role that analogies play in biochemistry learning. Analogies are an important teaching technique in biochemistry classes, being used more often in both biochemistry classes and textbooks than they are in high school chemistry classes and textbooks. Most biochemistry students like, pay particular attention to, and remember the analogies their instructors provide; and they use these analogies to understand, visualize, and recall information from class. Even though students like and use analogies, they do not understand what analogies are or the mechanism by which they improve learning. For the students, analogies are simply any teaching technique that eases understanding, visualization, or recall. Instructors, on the other hand, have a good understanding of what analogies are and of how they should be presented in class; but they do not use analogies as effectively as they should. They do not plan, explain or identify the limitations of the analogies they use in class. However, regardless of how effectively instructors present analogies in class, this study indicates that, in general, analogies are useful in promoting understanding, visualization, recall, and motivation in biochemistry students at all levels. They would be even more

  8. Barrier analogs: Long-term performance issues, preliminary studies, and recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W.J. [Rust Geotech, Inc., Grand Junction, CO (United States). Environmental Sciences Lab.; Chatters, J.C.; Last, G.V.; Bjornstad, B.N.; Link, S.O. [Pacific Northwest Lab., Richland, WA (United States); Hunter, C.R. [Cascade Earth Sciences, La Grande, OR (United States)

    1994-02-01

    The US Department of Energy`s Hanford Protective Barrier Development Program is funding studies of natural analogs of the long-term performance of waste site covers. Natural-analog studies examine past environments as evidence for projecting the future performance of engineered structures. The information generated by analog studies is needed to (1) evaluate the designs and results of short term experiments and demonstrations, (2) formulate performance-modeling problems that bound expected changes in waste site environments, and (3) understand emergent system attributes that cannot be evaluated with short-term experiments or computer models. Waste site covers will be part of dynamic environmental systems with attributes that transcend the traits of engineered components. This report discusses results of the previously unreported preliminary studies conducted in 1983 and 1984. These results indicate that analogs could play an important role in predicting the long-term behavior of engineered waste covers. Layered exposures of glacial-flood-deposited gravels mantled with silt or sand that resemble contemporary barrier designs were examined. Bergmounds, another anomaly left by cataclysmic glacial floods, were also examined as analogs of surface gravel.

  9. Parabolic flight as a spaceflight analog.

    Science.gov (United States)

    Shelhamer, Mark

    2016-06-15

    Ground-based analog facilities have had wide use in mimicking some of the features of spaceflight in a more-controlled and less-expensive manner. One such analog is parabolic flight, in which an aircraft flies repeated parabolic trajectories that provide short-duration periods of free fall (0 g) alternating with high-g pullout or recovery phases. Parabolic flight is unique in being able to provide true 0 g in a ground-based facility. Accordingly, it lends itself well to the investigation of specific areas of human spaceflight that can benefit from this capability, which predominantly includes neurovestibular effects, but also others such as human factors, locomotion, and medical procedures. Applications to research in artificial gravity and to effects likely to occur in upcoming commercial suborbital flights are also possible.

  10. Synthesis and Evaluation of Desmethyl Azumamide Analogs

    DEFF Research Database (Denmark)

    Maolanon, Alex

    the azumamide analogs; however, removal of the methyl group had a significant impact relative to the natural products. To understand this effect, the NMR structure was solved with the assistance from Casper Hoeck and Charlotte H. Gotfredsen and docked conformations were obtained from Niels J. Christensen...... and Peter Fristrup. Compared to the natural compounds, the 3Dstructure of the scaffold in the azumamide analogs were similar. Although a conclusion was not found, the preliminary docking results indicated favorable lipophilic interaction with the methyl group in the azumamides. Largazole is another...... macrocylic natural product with HDAC inhibitory activity. The compound has a thioester functionality in the side chain, which is hydrolyzed before interaction with the enzymes. In the attempt to mimic the prodrug nature of largazole, compounds containing a thiol group were designed, as it was hypothesized...

  11. Analog fault diagnosis by inverse problem technique

    KAUST Repository

    Ahmed, Rania F.

    2011-12-01

    A novel algorithm for detecting soft faults in linear analog circuits based on the inverse problem concept is proposed. The proposed approach utilizes optimization techniques with the aid of sensitivity analysis. The main contribution of this work is to apply the inverse problem technique to estimate the actual parameter values of the tested circuit and so, to detect and diagnose single fault in analog circuits. The validation of the algorithm is illustrated through applying it to Sallen-Key second order band pass filter and the results show that the detecting percentage efficiency was 100% and also, the maximum error percentage of estimating the parameter values is 0.7%. This technique can be applied to any other linear circuit and it also can be extended to be applied to non-linear circuits. © 2011 IEEE.

  12. Interference Alignment with Analog Channel State Feedback

    CERN Document Server

    Ayach, Omar El

    2010-01-01

    Interference alignment (IA) is a multiplexing gain optimal transmission strategy for the interference channel with an arbitrary number of users. While the achieved sum rate with IA is much higher than previously thought possible, the improvement comes at the cost of requiring network channel state information at the transmitters. This can be achieved by explicit feedback, a flexible yet costly approach that incurs large overhead and limits throughput. We propose using analog feedback as an alternative to limited feedback or reciprocity based alignment. We show that the full multiplexing gain observed with perfect channel knowledge is preserved by analog feedback and the mean loss in sum rate is bounded by a constant when signal-to-noise ratio is comparable in both forward and feedback channels. When such feedback quality is not quite possible, a fraction of the degrees of freedom is achieved. We consider the overhead of training and feedback and use this framework to optimize the system's effective throughput...

  13. Quantum Electric Circuits Analogous to Ballistic Conductors

    OpenAIRE

    2007-01-01

    The conductance steps in a constricted two-dimensional electron gas and the minimum conductivity in graphene are related to a new uncertainty relation between electric charge and conductance in a quantized electric circuit that mimics the electric transport in mesoscopic systems. This uncertainty relation makes specific use of the discreteness of electric charge. Quantum electric circuits analogous to both constricted two-dimensional electron gas and graphene are introduced. In the latter cas...

  14. An introduction to analog and digital communications

    CERN Document Server

    Haykin, Simon

    2012-01-01

    The second edition of this accessible book provides readers with an introductory treatment of communication theory as applied to the transmission of information-bearing signals. While it covers analog communications, the emphasis is placed on digital technology. It begins by presenting the functional blocks that constitute the transmitter and receiver of a communication system. Readers will next learn about electrical noise and then progress to multiplexing and multiple access techniques.

  15. Analog of landau Levels to Electric Dipole

    CERN Document Server

    Ribeiro, L R; Nascimento, J R; Furtado, Claudio

    2006-01-01

    In this article we discuss the analogy between the dynamics of a neutral particle with an electric dipole, in the presence of configuration of magnetic field, with Landau level quantization for charged particle. We analyze this quantization based on the He-Mckelar-Wilkens interaction developed of similar way that Ericsson and Sj\\"oqvist[Phys Rev. A {\\bf 65} 013607 (2001)] was analyzed the Landau-Aharonov-Casher effect. The energy level and eingenfuctions and eigenvalues are obtained.

  16. Neurotoxic Alkaloids: Saxitoxin and Its Analogs

    OpenAIRE

    Mihali, Troco K; Moffitt, Michelle C.; Neilan, Brett A.; Maria Wiese; D’Agostino, Paul M.

    2010-01-01

    Saxitoxin (STX) and its 57 analogs are a broad group of natural neurotoxic alkaloids, commonly known as the paralytic shellfish toxins (PSTs). PSTs are the causative agents of paralytic shellfish poisoning (PSP) and are mostly associated with marine dinoflagellates (eukaryotes) and freshwater cyanobacteria (prokaryotes), which form extensive blooms around the world. PST producing dinoflagellates belong to the genera Alexandrium, Gymnodinium and Pyrodinium whilst production has been identified...

  17. Analog-digital codesign using coarse quantization

    Science.gov (United States)

    Kokkeler, Andre Bernardus Joseph

    With regards to electronic systems, two important trends can be observed. The first trend is generally known as Moore's law: the digital processing capacity per chip is increasing a factor two every 18 months. Another part of the first trend is that the performance increase of integrated linear or analog processing is slow, a factor two every 4.7 years. The second trend is that the rate of data exchange between electronic systems is increasing rapidly. Because of these high data rates especially the design of data converters from analog to digital (ADCs) is demanding. For a specific set of applications, the requirements for the ADC can be relaxed by reducing the resolution of the conversion from analog to digital. Within these specific applications, signal characteristics rather than instantaneous values of the signal are determined. Reducing the resolution to an extreme extend is called 'coarse quantization'. The design of mixed signal systems is guided by a Y-chart design methodology. Analog-Digital Codesign, guided by the Y-chart approach, leads to mixed-signal systems with reduced costs compared to systems designed with the traditional methodology. The Y-chart approach also enables the use of coarse quantization as an additional design parameter to further reduce costs. This is illustrated by two case studies. The first case study concentrates on the design of a digital predistorter for Power Amplifiers (PAs) in telecommunication transmitters. In the second case study, we reconsider the design of a part of a Radio Telescope, used for Radio Astronomy. This part is called the Tied Array Adder and it sums signals from different telescopes. Both case studies show that coarse quantization can lead to mixed-signal systems with lower costs but system parameters will change. The explicit reconsideration of functional specifications, facilitated by the Y-chart approach, is therefore essential for the introduction of coarse quantization.

  18. HOW TO USE ANALOGIES FOR BREAKTHROUGH INNOVATIONS

    OpenAIRE

    CORNELIUS HERSTATT; KATHARINA KALOGERAKIS

    2005-01-01

    Analogies can trigger breakthrough ideas in new product development. Numerous examples demonstrate that substantial innovations often result from transferring problem solutions from one industry or domain to another. For instance, the designers of the new running show generation of Nike, "Nike SHOX", use the same suspension concept like the technologies applied for formula 1 racing cars, or the biological Lotus-effect leading to the evelopment of various self-cleaning surfaces. Academic resea...

  19. How to use analogies for breakthrough innovations

    OpenAIRE

    Schild, Katharina; Herstatt, Cornelius; Lüthje, Christian

    2004-01-01

    Analogies can trigger breakthrough ideas in new product development. Numerous examples demonstrate that substantial innovations often result from transferring problem solutions from one industry or domain to another. For instance, the designers of the new running shoe generation of Nike, “Nike SHOX”, use the same suspension concept like the technologies applied for Formula 1 racing cars, or the biological Lotus-effect led to the development of various self-cleaning surfaces. Academic resea...

  20. Transition State Analog Inhibitors for Esterases.

    Science.gov (United States)

    1983-06-02

    Propanones." SCIENTIFIC PERSONNEL SUPPORTED BY THIS PROJECT AND DEGREES AWARDED DURING THIS REPORTING PERIOD Dr. Alan Dafforn Dr. Antoon Brouwer Dr. John P...294, Raven Press, New York. 11. Hansch, C. and Leo , A., (1979) "Substituent Constants for Correlation Analysis in Chemistry and Biology," pp. 69-70...BORONIC ACIDS AS 1INSITION STATE ANALOG INHIBITORS OF ACTYLCHOLINESTERASE by Alan Dafforn and Antoon C. Brouwer Department of Chemistry Bowling Green

  1. Survey of Evaluated Isobaric Analog States

    Energy Technology Data Exchange (ETDEWEB)

    MacCormick, M., E-mail: maccorm@ipno.in2p3.fr [Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, 91406 Orsay CEDEX (France); Audi, G. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, CNRS/IN2P3, Université Paris-Sud, Bât. 108, F-91405 Orsay Campus (France)

    2014-06-15

    Isobaric analog states (IAS) can be used to estimate the masses of members belonging to the same isospin multiplet. Experimental and estimated IAS have been used frequently within the Atomic Mass Evaluation (AME) in the past, but the associated set of evaluated masses have been published for the first time in AME2012 and NUBASE2012. In this paper the current trends of the isobaric multiplet mass equation (IMME) coefficients are shown. The T = 2 multiplet is used as a detailed illustration.

  2. Theory of analogous force on number sets

    Science.gov (United States)

    Canessa, Enrique

    2003-10-01

    A general statistical thermodynamic theory that considers given sequences of x-integers to play the role of particles of known type in an isolated elastic system is proposed. By also considering some explicit discrete probability distributions px for natural numbers, we claim that they lead to a better understanding of probabilistic laws associated with number theory. Sequences of numbers are treated as the size measure of finite sets. By considering px to describe complex phenomena, the theory leads to derive a distinct analogous force fx on number sets proportional to (∂ px/∂ x) T at an analogous system temperature T. In particular, this leads to an understanding of the uneven distribution of integers of random sets in terms of analogous scale invariance and a screened inverse square force acting on the significant digits. The theory also allows to establish recursion relations to predict sequences of Fibonacci numbers and to give an answer to the interesting theoretical question of the appearance of the Benford's law in Fibonacci numbers. A possible relevance to prime numbers is also analyzed.

  3. Using Analogs for Chemistry Problem Solving: Does It Increase Understanding?

    Science.gov (United States)

    Friedel, Arthur W.; And Others

    1990-01-01

    Discussed is the effectiveness of using analogies in chemistry instruction. Students' mathematics anxiety, spatial visualization skill, and proportional reasoning ability were found to be important aptitudes for determining chemistry achievement. The relationship between analogs and algorithms is described. (KR)

  4. Creative Analogy Use in a Heterogeneous Design Team

    DEFF Research Database (Denmark)

    Christensen, Bo; Ball, Linden J.

    2016-01-01

    the design dialogue derived from team members with highly disparate educational backgrounds. Our analyses revealed that analogies that matched (versus mismatched) educational backgrounds were generated and revisited more frequently, presumably because they were more accessible. Matching analogies were also...

  5. A Reasoning System using Inductive Inference of Analogical Union

    OpenAIRE

    Miyahara, Tetsuhiro

    1988-01-01

    Analogical reasoning derives a new fact based on the analogous facts previously known. Inductive inference is a process of gaining a general rule from examples. We propose a new reasoning system using inductive inference and analogical reasoning. which is applicable to intellectual information processing and we characterize its power. Given an enumeration of paired examples. this system inductively infers a program representing the paring and constructs an analogical union. It reasons by anal...

  6. Functional DNA: Teaching Infinite Series through Genetic Analogy

    Science.gov (United States)

    Kowalski, R. Travis

    2011-01-01

    This article presents an extended analogy that connects infinite sequences and series to the science of genetics, by identifying power series as "DNA for a function." This analogy allows standard topics such as convergence tests or Taylor approximations to be recast in a "forensic" light as mathematical analogs of genetic concepts such as DNA…

  7. Analogy Use in Eighth-Grade Mathematics Classrooms

    Science.gov (United States)

    Richland, Lindsey E.; Holyoak, Keith J.; Stigler, James W.

    2004-01-01

    Analogical reasoning has long been believed to play a central role in mathematics learning and problem solving (see Genter, Holyoak, & Kokinov, 2001); however, little is known about how analogy is used in everyday instructional contexts. This article examines analogies produced in naturally occurring U.S. mathematics lessons to explore…

  8. Analogical Instruction in Statistics: Implications for Social Work Educators

    Science.gov (United States)

    Thomas, Leela

    2008-01-01

    This paper examines the use of analogies in statistics instruction. Much has been written about the difficulty social work students have with statistics. To address this concern, Glisson and Fischer (1987) called for the use of analogies. Understanding of analogical problem solving has surged in the last few decades with the integration of…

  9. Anti-inflammatory effect of thalidomide dithiocarbamate and dithioate analogs.

    Science.gov (United States)

    Talaat, Roba; El-Sayed, Waheba; Agwa, Hussein S; Gamal-Eldeen, Amira M; Moawia, Shaden; Zahran, Magdy A H

    2015-08-05

    Thalidomide has anti-inflammatory, immunomodulatory, and anti-angiogenic properties. It has been used to treat a variety of cancers and autoimmune diseases. This study aimed to characterize anti-inflammatory activities of novel thalidomide analogs by exploring their effects on splenocytes proliferation and macrophage functions and their antioxidant activity. MTT assay was used to assess the cytotoxic effect of thalidomide analogs against splenocytes. Tumor necrosis factor (TNF-α) and nuclear factor kappa B (NF-κB-P65) were determined by enzyme-linked immunosorbent assay (ELISA). Nitric oxide (NO) was estimated by colorimetric assay. Antioxidant activity was examined by ORAC assay. Our results demonstrated that thalidomide dithioate analog 2 and thalidomide dithiocarbamate analog 4 produced a slight increase in splenocyte proliferation compared with thalidomide. Thalidomide dithiocarbamate analog 1 is a potent inhibitor of TNF-α production, whereas thalidomide dithiocarbamate analog 5 is a potent inhibitor of both TNF-α and NO. Analog 2 has a pronounced inhibitory effect on NF-κB-P65 production level. All thalidomide analogs showed prooxidant activity against hydroxyl (OH) radical. Analog 1 and thalidomide dithioate analog 3 have prooxidant activity against peroxyl (ROO) radical in relation to thalidomide. On the other hand, analog 4 has a potent scavenging capacity against peroxyl (ROO) radical compared with thalidomide. Taken together, the results of this study suggest that thalidomide analogs might have valuable anti-inflammatory activities with more pronounced effect than thalidomide itself.

  10. Analogies in Medicine: Valuable for Learning, Reasoning, Remembering and Naming

    Science.gov (United States)

    Pena, Gil Patrus; Andrade-Filho, Jose de Souza

    2010-01-01

    Analogies are important tools in human reasoning and learning, for resolving problems and providing arguments, and are extensively used in medicine. Analogy and similarity involve a structural alignment or mapping between domains. This cognitive mechanism can be used to make inferences and learn new abstractions. Through analogies, we try to…

  11. Investigating and Theorizing Discourse during Analogy Writing in Chemistry

    Science.gov (United States)

    Bellocchi, Alberto; Ritchie, Stephen M.

    2011-01-01

    Explanations of the role of analogies in learning science at a cognitive level are made in terms of creating bridges between new information and students' prior knowledge. In this empirical study of learning with analogies in an 11th grade chemistry class, we explore an alternative explanation at the "social" level where analogy shapes…

  12. Inviting Argument by Analogy: Analogical-Mapping-Based Comparison Activities as a Scaffold for Small-Group Argumentation

    Science.gov (United States)

    Emig, Brandon R.; McDonald, Scott; Zembal-Saul, Carla; Strauss, Susan G.

    2014-01-01

    This study invited small groups to make several arguments by analogy about simple machines. Groups were first provided training on analogical (structure) mapping and were then invited to use analogical mapping as a scaffold to make arguments. In making these arguments, groups were asked to consider three simple machines: two machines that they had…

  13. Design and test challenges in Nano-scale analog and mixed CMOS technology

    OpenAIRE

    2011-01-01

    The continuous increase of integration densities in Complementary Metal–Oxide–Semiconductor (CMOS)technology has driven the rapid growth of very large scale integrated (VLSI) circuit for today's high-tech electronics industries from consumer products to telecommunications and computers. As CMOS technologies are scaled down into the nano meter range, analog and mixed integrated circuit (IC) design and testing have become a real challenge to ensure the functionality and quality of the product. ...

  14. SSERVI Analog Regolith Simulant Testbed Facility

    Science.gov (United States)

    Minafra, Joseph; Schmidt, Gregory; Bailey, Brad; Gibbs, Kristina

    2016-10-01

    The Solar System Exploration Research Virtual Institute (SSERVI) at NASA's Ames Research Center in California's Silicon Valley was founded in 2013 to act as a virtual institute that provides interdisciplinary research centered on the goals of its supporting directorates: NASA Science Mission Directorate (SMD) and the Human Exploration & Operations Mission Directorate (HEOMD).Primary research goals of the Institute revolve around the integration of science and exploration to gain knowledge required for the future of human space exploration beyond low Earth orbit. SSERVI intends to leverage existing JSC1A regolith simulant resources into the creation of a regolith simulant testbed facility. The purpose of this testbed concept is to provide the planetary exploration community with a readily available capability to test hardware and conduct research in a large simulant environment.SSERVI's goals include supporting planetary researchers within NASA, other government agencies; private sector and hardware developers; competitors in focused prize design competitions; and academic sector researchers.SSERVI provides opportunities for research scientists and engineers to study the effects of regolith analog testbed research in the planetary exploration field. This capability is essential to help to understand the basic effects of continued long-term exposure to a simulated analog test environment.The current facility houses approximately eight tons of JSC-1A lunar regolith simulant in a test bin consisting of a 4 meter by 4 meter area, including dust mitigation and safety oversight.Facility hardware and environment testing scenarios could include, Lunar surface mobility, Dust exposure and mitigation, Regolith handling and excavation, Solar-like illumination, Lunar surface compaction profile, Lofted dust, Mechanical properties of lunar regolith, Surface features (i.e. grades and rocks)Numerous benefits vary from easy access to a controlled analog regolith simulant testbed, and

  15. Direct Computation on the Kinetic Spectrophotometry

    DEFF Research Database (Denmark)

    Hansen, Jørgen-Walther; Broen Pedersen, P.

    1974-01-01

    This report describes an analog computer designed for calculations of transient absorption from photographed recordings of the oscilloscope trace of the transmitted light intensity. The computer calculates the optical density OD, the natural logarithm of OD, and the natural logarithm of the diffe...

  16. Integrated Analogic Filter Tuning System Design

    Directory of Open Access Journals (Sweden)

    Karolis Kiela

    2016-06-01

    Full Text Available Parameters of integrated analog filters can vary due to temperatu-re change, IC process variation and therefore they should have dedicated tuning circuits that compensate these imperfections. A method is proposed that speeds up switched resistor bank design while taking into account the required tuning range and step size. A novel counter structure is used in the tuning circuit that is ba-sed on successive approximation approach. The proposed swit-ched resistor design method and tuning circuit are designed in 0.18 μm CMOS technology and verified. Results are compared to existing tuning circuit designs.

  17. Reconfiguration of Analog Electronics for Extreme Environments

    Science.gov (United States)

    Stoica, Adrian; Zebulum, Ricardo; Keymeulen, Didier; Guo, Xin

    2005-01-01

    This paper argues in favor of adaptive reconfiguration as a technique to expand the operational envelope of analog electronics for extreme environments (EE). On a reconfigurable device, although component parameters change in EE, as long as devices still operate, albeit degraded, a new circuit design, suitable for new parameter values, may be mapped into the reconfigurable structure to recover the initial circuit function. Laboratory demonstrations of this technique were performed by JPL in several independent experiments in which bulk CMOS reconfgurable devices were exposed to, and degraded by, high temperatures (approx.300 C) or radiation (300kRad TID), and then recovered by adaptive reconfiguration using evolutionary search algorithms.

  18. An Analog VLSI Saccadic Eye Movement System

    OpenAIRE

    1994-01-01

    In an effort to understand saccadic eye movements and their relation to visual attention and other forms of eye movements, we - in collaboration with a number of other laboratories - are carrying out a large-scale effort to design and build a complete primate oculomotor system using analog CMOS VLSI technology. Using this technology, a low power, compact, multi-chip system has been built which works in real-time using real-world visual inputs. We describe in this paper the performance of a...

  19. Microstore: the Stanford analog memory unit

    Energy Technology Data Exchange (ETDEWEB)

    Walker, J.T.; Chae, S.I.; Shapiro, S.; Larsen, R.S.

    1984-11-01

    An NMOS device has been developed which provides high speed analog signal storage and readout for time expansion of transient signals. This device takes advantage of HMOS-1 VLSI technology to implement an array of 256 storage cells. Sequential samples of an input waveform can be taken every 5 ns while providing an effective sampling aperture time of less than 1 ns. The design signal-to-noise ratio is 1 part in 2000. Digital control circuitry is provided on the chip for controlling the read-in and read-out processes. A reference circuit is incorporated in the chip for first order compensation of leakage drifts, sampling pedestals, and temperature effects.

  20. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1999-01-01

    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...... by employing a feedback loop. The gate oxide will not be subject to voltages exceeding the supply voltage difference.Realistic switches have been simulated with HSPICE. The simulations show that the switch circuits operate very well, even when the supply voltage approaches the technology's threshold voltage....

  1. Analogy among microfluidics, micromechanics, and microelectronics.

    Science.gov (United States)

    Li, Sheng-Shian; Cheng, Chao-Min

    2013-10-07

    We wish to illuminate the analogous link between microfluidic-based devices, and the already established pairing of micromechanics and microelectronics to create a triangular/three-way scientific relationship as a means of interlinking familial disciplines and accomplishing two primary goals: (1) to facilitate the modeling of multidisciplinary domains; and, (2) to enable us to co-simulate the entire system within a compact circuit simulator (e.g., Cadence or SPICE). A microfluidic channel-like structure embedded in a micro-electro-mechanical resonator via our proposed CMOS-MEMS technology is used to illustrate the connections among microfluidics, micromechanics, and microelectronics.

  2. Novel Gemini vitamin D3 analogs

    DEFF Research Database (Denmark)

    Okamoto, Ryoko; Gery, Sigal; Kuwayama, Yoshio

    2014-01-01

    anticancer potency, but similar toxicity causing hypercalcemia. We focused on the effect of these compounds on the stimulation of expression of human cathelicidin antimicrobial peptide (CAMP) whose gene has a vitamin D response element in its promoter. Expression of CAMP mRNA and protein increased in a dose......-response fashion after exposure of acute myeloid leukemia (AML) cells to the Gemini analog, BXL-01-126, in vitro. A xenograft model of AML was developed using U937 AML cells injected into NSG-immunodeficient mice. Administration of vitamin D3 compounds to these mice resulted in substantial levels of CAMP...

  3. An optical analog of quantum optomechanics

    CERN Document Server

    Rodríguez-Lara, B M

    2014-01-01

    We present a two-dimensional array of nearest-neighbor coupled waveguides that is the optical analog of a quantum optomechanical system. We show that the quantum model predicts the appearance of effective column isolation, diagonal-coupling and other non-trivial couplings in the two-dimensional photonic lattice under a standard approximation from ion-trap cavity electrodynamics. We provide an approximate impulse function for the case of effective column isolation and compare it with exact numerical propagation in the photonic lattice.

  4. Analogic China map constructed by DNA

    Institute of Scientific and Technical Information of China (English)

    QIAN Lulu; HE Lin; WANG Ying; ZHANG Zhao; ZHAO Jian; PAN Dun; ZHANG Yi; LIU Qiang; FAN Chunhai; HU Jun

    2006-01-01

    In this research, a nanoscale DNA structure of analogic China map is created. The nanostructure of roughly 150 nm in diameter with a spatial resolution of 6 nm is purely constructed by folding DNA. The picture observed by atomic force microscopy (AFM) is almost identical with the designed shape. The DNA origami technology invented by Rothemund in 2006 is employed in the construction of this shape, which has proved the capability of constructing almost any complicated shape enabled by DNA origami, and provides new bottom-up method for constructing nanostructures.

  5. Analogies as categorization phenomena: Studies from scientific discourse

    Science.gov (United States)

    Atkins, Leslie Jill

    Studies on the role of analogies in science classrooms have tended to focus on analogies that come from the teacher or curriculum, and not the analogies that students generate. Such studies are derivative of an educational system that values content knowledge over scientific creativity, and derivative of a model of teaching in which the teacher's role is to convey content knowledge. This dissertation begins with the contention that science classrooms should encourage scientific thinking and one role of the teacher is to model that behavior and identify and encourage it in her students. One element of scientific thinking is analogy. This dissertation focuses on student-generated analogies in science, and offers a model for understanding these. I provide evidence that generated analogies are assertions of categorization, and the base of an analogy is the constructed prototype of an ad hoc category. Drawing from research on categorization, I argue that generated analogies are based in schemas and cognitive models. This model allows for a clear distinction between analogy and literal similarity; prior to this research analogy has been considered to exist on a spectrum of similarity, differing from literal similarity to the degree that structural relations hold but features do not. I argue for a definition in which generated analogies are an assertion of an unexpected categorization: that is, they are asserted as contradictions to an expected schema.

  6. Analogies in medicine: valuable for learning, reasoning, remembering and naming.

    Science.gov (United States)

    Pena, Gil Patrus; Andrade-Filho, José de Souza

    2010-10-01

    Analogies are important tools in human reasoning and learning, for resolving problems and providing arguments, and are extensively used in medicine. Analogy and similarity involve a structural alignment or mapping between domains. This cognitive mechanism can be used to make inferences and learn new abstractions. Through analogies, we try to explain a knowledge to be achieved (the target), with pieces of information already familiar to the learner (the source), keeping in mind the constraints of similarity, structure and purpose. The purpose of this essay is to examine the use of analogies in medicine. We provide a brief review of the theoretical basis of analogical reasoning. This theoretical background is discussed in the light of actual examples of analogies retrieved from medical literature. In medicine, analogies have long been used to explain several physiologic and pathologic processes. Besides deeper structural relations, superficial attribute similarity is extensively used in many medical specialties. These attribute similarities are important in naming, categorizing and classifying, and play a role as learning and memorizing tools. Analogies also serve as basis for medical nomenclature. The choice of the source of analogies is highly dependent on cultural background, and may derive from ancient or diverse cultures. Learning by analogies may thus require research on culture diversity in order to establish an adequate justification and to comprehend the purpose of an analogy.

  7. Unconscious violinists and the use of analogies in moral argument.

    Science.gov (United States)

    Wiland, E

    2000-12-01

    Analogies are the stuff out of which normative moral philosophy is made. Certainly one of the most famous analogies constructed by a philosopher in order to argue for a specific controversial moral conclusion is the one involving Judith Thomson's unconscious violinist. Reflection upon this analogy is meant to show us that abortion is generally not immoral even if the prenatal have the same moral status as the postnatal. This was and still is a controversial conclusion, and yet the analogy does seem to reveal in a very vivid way what makes abortion a reasonable response to a terrible situation. But Thomson's example has frequently been attacked on all sides for not being truly analogous to abortion. Here I develop a brand new analogy that sheds light on the issue with which Thomson was concerned, while at the same time avoiding most of the more serious objections made to her analogy.

  8. Continuous-time analog filter in CMOS nanoscale era

    Science.gov (United States)

    Baschirotto, A.; De Matteis, M.; Pezzotta, A.; D'Amico, S.

    2014-04-01

    Analog filters are key blocks in analog signal processing. They are widely employed in many systems, like wireless transceivers, detectors read-out, sensors interfaces, etc. The IC technology choice for such systems is mainly dictated by the requirements of high speed and low power consumption of digital circuits. This pushed an impressive movement towards scaled technology and this has important consequences on the analog circuits design. The impact of technology scaling down to nanometre scale on analog filters design is here investigated. For instance, supply voltage reduction in analog filters limits circuits design solutions and could result in higher power consumption. Moreover, at the same time, innovative systems push analog filters to get higher and higher operation frequencies, due to the increasing bandwidth/speed requirements. Recent solutions for efficient low-voltage and high frequency analog filters in nanometre technology are described.

  9. Use of analogy in learning physics: The role of representations

    Directory of Open Access Journals (Sweden)

    Noah D. Finkelstein

    2006-07-01

    Full Text Available Previous studies have demonstrated that analogies can promote student learning in physics and can be productively taught to students to support their learning, under certain conditions. We build on these studies to explore the use of analogy by students in a large introductory college physics course. In the first large-scale study of its kind, we demonstrate that different analogies can lead to varied student reasoning. When different analogies were used to teach electromagnetic (EM waves, we found that students explicitly mapped characteristics either of waves on strings or sound waves to EM waves, depending upon which analogy students were taught. We extend these results by investigating how students use analogies. Our findings suggest that representational format plays a key role in the use of analogy.

  10. Analog memristive synapse in spiking networks implementing unsupervised learning

    Directory of Open Access Journals (Sweden)

    Erika Covi

    2016-10-01

    Full Text Available Emerging brain-inspired architectures call for devices that can emulate the functionality of biological synapses in order to implement new efficient computational schemes able to solve ill-posed problems. Various devices and solutions are still under investigation and, in this respect, a challenge is opened to the researchers in the field. Indeed, the optimal candidate is a device able to reproduce the complete functionality of a synapse, i.e. the typical synaptic process underlying learning in biological systems (activity-dependent synaptic plasticity. This implies a device able to change its resistance (synaptic strength, or weight upon proper electrical stimuli (synaptic activity and showing several stable resistive states throughout its dynamic range (analog behavior. Moreover, it should be able to perform spike timing dependent plasticity (STDP, an associative homosynaptic plasticity learning rule based on the delay time between the two firing neurons the synapse is connected to. This rule is a fundamental learning protocol in state-of-art networks, because it allows unsupervised learning. Notwithstanding this fact, STDP-based unsupervised learning has been proposed several times mainly for binary synapses rather than multilevel synapses composed of many binary memristors. This paper proposes an HfO2-based analog memristor as a synaptic element which performs STDP within a small spiking neuromorphic network operating unsupervised learning for character recognition. The trained network is able to recognize five characters even in case incomplete or noisy characters are displayed and it is robust to a device-to-device variability of up to +/-30%.

  11. The gravitational analog of Faraday's induction law

    Science.gov (United States)

    Zile, Daniel; Overduin, James

    2015-04-01

    Michael Faraday, the discoverer of electromagnetic induction, was convinced that there must also be a gravitational analog of this law, and he carried out drop-tower experiments in 1849 to look for the electric current induced in a coil by changes in gravitational flux through the coil. This work, now little remembered, was in some ways the first investigation of what we would now call a unified-field theory. We revisit Faraday's experiments in the light of current knowledge and ask what might be learned if they were to be performed today. We then review the gravitational analog for Faraday's law that arises within the vector (or gravito-electromagnetic) approximation to Einstein's theory of general relativity in the weak-field, low-velocity limit. This law relates spinning masses and induced ``mass currents'' rather than spinning charges and electric currents, but is otherwise remarkably similar to its electromagnetic counterpart. The predicted effects are completely unobservable in everyday settings like those envisioned by Faraday, but are thought to be relevant in astrophysical contexts like the accretion disks around collapsed stars, thus bearing out Faraday's remarkable intuition. Undergraduate student.

  12. Developing Fluorescent Hyaluronan Analogs for Hyaluronan Studies

    Directory of Open Access Journals (Sweden)

    Shi Ke

    2012-02-01

    Full Text Available Two kinds of fluorescent hyaluronan (HA analogs, one serving as normal imaging agent and the other used as a biosensitive contrast agent, were developed for the investigation of HA uptake and degradation. Our approach of developing HA imaging agents depends on labeling HA with varying molar percentages of a near-infrared (NIR dye. At low labeling ratios, the hyaluronan uptake can be directly imaged while at high labeling ratios, the fluorescent signal is quenched and signal generation occurs only after degradation. It is found that the conjugate containing 1%–2% NIR dye can be used as a normal optical imaging agent, while bioactivable imaging agents are formed at 6% to 17% dye loading. It was determined that the conjugation of dye to HA with different loading percentages does not impact HA biodegradation by hyaluronidase (Hyal. The feasibility of using these two NIR fluorescent hyaluronan analogs for HA investigation was evaluated in vivo with optical imaging. The data demonstrates that the 1% dye loaded fluorescent HA can be used to monitor the behavior of HA and its fragments, whereas bioactivatable HA imaging agent (17% dye in HA is more suitable for detecting HA fragments.

  13. Antarctic analog for dilational bands on Europa

    Science.gov (United States)

    Hurford, T. A.; Brunt, K. M.

    2014-09-01

    Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

  14. Amygdalin analogs for the treatment of psoriasis.

    Science.gov (United States)

    Perez, Juan J

    2013-05-01

    Psoriasis is one of the most prevalent immune-mediated illness worldwide. The disease can still only be managed rather than cured, so treatments are aimed at clearing skin lesions and preventing their recurrence. Several treatments are available depending on the extent of the psoriatic lesion. Among the topical treatments corticostereoids, vitamin D3 analogs and retinoids are commonly used. However, these treatments may have adverse effects in the long term. Conversely, systemic conventional treatments include immunosuppresors such as cyclosporin or methotrexate associated with high toxicity levels. Biologicals are alternative therapeutical agents introduced in the last 10 years. These include fusion proteins or monoclonal antibodies designed to inhibit the action of specific cytokines or to prevent T-lymphocyte activation. However, due to recent knowledge on the etiology of the disease, diverse new small molecules have appeared as promising alternatives for the treatment of psoriasis. Among them, inhibitors of JAK3, inhibitors of PDE 4 and amygdalin analogs. The latter are promising small molecules presently in preclinical studies which are the object of the present report.

  15. Analog IC reliability in nanometer CMOS

    CERN Document Server

    Maricau, Elie

    2013-01-01

    This book focuses on modeling, simulation and analysis of analog circuit aging. First, all important nanometer CMOS physical effects resulting in circuit unreliability are reviewed. Then, transistor aging compact models for circuit simulation are discussed and several methods for efficient circuit reliability simulation are explained and compared. Ultimately, the impact of transistor aging on analog circuits is studied. Aging-resilient and aging-immune circuits are identified and the impact of technology scaling is discussed.   The models and simulation techniques described in the book are intended as an aid for device engineers, circuit designers and the EDA community to understand and to mitigate the impact of aging effects on nanometer CMOS ICs.   ·         Enables readers to understand long-term reliability of an integrated circuit; ·         Reviews CMOS unreliability effects, with focus on those that will emerge in future CMOS nodes; ·         Provides overview of models for...

  16. C-Glycosyl Analogs of Oligosaccharides

    Science.gov (United States)

    Vauzeilles, Boris; Urban, Dominique; Doisneau, Gilles; Beau, Jean-Marie

    This chapter covers the synthesis of a large collection of "C-oligosaccharides ", synthetic analogs of naturally occurring oligosaccharides in which a carbon atom replaces the anomeric, interglycosidic oxygen atom. These non-natural constructs are stable to chemical and enzymatic degradation, and are primarily devised to probe carbohydrate-based biological processes. These mainly target carbohydrate-protein interactions such as the modulation of glycoenzyme (glycosylhydrolases and transferases) activities or the design of ligands for lectin Carbohydrate Recognition Domains. The discussion is based on the key carbon-carbon bond assembling steps on carbohydrate templates: ionic (anionic and cationic chemistries, sigmatropic rearrangements) or radical assemblage, and olefin metathesis. Synthetic schemes in which at least one of the monosaccharide units is constructed by total synthesis or by cyclization of acyclic chiral chains are presented separately in a "partial de novo synthesis" section. The review also provides comments, when they are known, on the conformational and binding properties of these synthetic analogs, as well as their biological behavior when tested.

  17. Photonic analog-to-digital converters

    Science.gov (United States)

    Valley, George C.

    2007-03-01

    This paper reviews over 30 years of work on photonic analog-to-digital converters. The review is limited to systems in which the input is a radio-frequency (RF) signal in the electronic domain and the output is a digital version of that signal also in the electronic domain, and thus the review excludes photonic systems directed towards digitizing images or optical communication signals. The state of the art in electronic ADCs, basic properties of ADCs and properties of analog optical links, which are found in many photonic ADCs, are reviewed as background information for understanding photonic ADCs. Then four classes of photonic ADCs are reviewed: 1) photonic assisted ADC in which a photonic device is added to an electronic ADC to improve performance, 2) photonic sampling and electronic quantizing ADC, 3) electronic sampling and photonic quantizing ADC, and 4) photonic sampling and quantizing ADC. It is noted, however, that all 4 classes of “photonic ADC” require some electronic sampling and quantization. After reviewing all known photonic ADCs in the four classes, the review concludes with a discussion of the potential for photonic ADCs in the future.

  18. Metaphor and analogy in everyday problem solving.

    Science.gov (United States)

    Keefer, Lucas A; Landau, Mark J

    2016-11-01

    Early accounts of problem solving focused on the ways people represent information directly related to target problems and possible solutions. Subsequent theory and research point to the role of peripheral influences such as heuristics and bodily states. We discuss how metaphor and analogy similarly influence stages of everyday problem solving: Both processes mentally map features of a target problem onto the structure of a relatively more familiar concept. When individuals apply this structure, they use a well-known concept as a framework for reasoning about real world problems and candidate solutions. Early studies found that analogy use helped people gain insight into novel problems. More recent research on metaphor goes further to show that activating mappings has subtle, sometimes surprising effects on judgment and reasoning in everyday problem solving. These findings highlight situations in which mappings can help or hinder efforts to solve problems. WIREs Cogn Sci 2016, 7:394-405. doi: 10.1002/wcs.1407 For further resources related to this article, please visit the WIREs website.

  19. Metastatic Insulinoma Managed with Radiolabeled Somatostatin Analog

    Science.gov (United States)

    Costa, Ricardo; Bacchi, Carlos E.; Almeida Filho, Paulo

    2013-01-01

    Insulinoma is a rare pancreatic neuroendocrine tumor. Overproduction of insulin and associated hypoglycemia are hallmark features of this disease. Diagnosis can be made through demonstration of hypoglycemia and elevated plasma levels of insulin or C-Peptide. Metastatic disease can be detected through computerized tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT. Somatostatin receptor scintigraphy can be used not only to document metastatic disease but also as a predictive marker of the benefit from therapy with radiolabeled somatostatin analog. Unresectable metastatic insulinomas may present as a major therapeutic challenge for the treating physician. When feasible, resection is the mainstay of treatment. Prevention of hypoglycemia is a crucial goal of therapy for unresectable/metastatic tumors. Diazoxide, hydrochlorothiazide, glucagon, and intravenous glucose infusions have been used for glycemic control yielding temporary and inconsistent results. Sandostatin and its long-acting depot forms have occasionally been used in the treatment of Octreoscan-positive insulinomas. Herein, we report a case of metastatic insulinoma with very difficult glycemic control successfully treated with the radiolabeled somatostatin analog lutetium (177LU). PMID:24455330

  20. The exoplanets analogy to the Multiverse

    CERN Document Server

    Kinouchi, Osame

    2015-01-01

    The idea of a Mutiverse is controversial, although it is a natural possible solution to particle physics and cosmological fine-tuning problems (FTPs). Here I explore the analogy between the Multiverse proposal and the proposal that there exist an infinite number of stellar systems with planets in a flat Universe, the Multiplanetverse. Although the measure problem is present in this scenario, the idea of a Multiplanetverse has predictive power, even in the absence of direct evidence for exoplanets that appeared since the 90s. We argue that the fine-tuning of Earth to life (and not only the fine-tuning of life to Earth) could predict with certainty the existence of exoplanets decades or even centuries before that direct evidence. Several other predictions can be made by studying only the Earth and the Sun, without any information about stars. The analogy also shows that theories that defend that the Earth is the unique existing planet and that, at the same time, is fine-tuned to life by pure chance (or pure phy...

  1. Isolation and characterization of soybean NBS analogs

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Isolation of plant resistance genes is greatly helpful to crop resistance breeding and the insight of resistance mechanism. The cloned plant resistance genes are classified into four classes according to their putative structural domain, of which the majority possesses nucleotide-binding site (NBS) domain that consists of P-loop, kinase2a and kinase3a. The conservation of this domain affords the potential possibility of cloning the plant resistance genes, which is homology-based cloning technique. In the present study, the degenerate oligonucleotide primers were designed according to the tobacco N and Arabidopsis RPS2, and 358 clones were isolated from the genomic DNA of resistance soybean cultivar Kefeng1, resistant to soybean mosaic virus, and 4 open-reading NBS analogs were finally characterized and designated as KNBS1, KNBS2, KNBS3 and KNBS4. Southern hybridization suggested that they were present with multicopy in the soybean genome; KNBS4 was mapped to F linkage group and KNBS2 co-located J linkage group with the SCAR marker of Rsa resistant to soybean mosaic virus by RFLP analysis. Northern analysis suggested that KNBS2- related sequence was low and constitutively expressed in the root, stem and leaves of soybean. The detailed characterization of NBS analogs is very helpful to ultimately cloning the soybean resistance gene.

  2. Antarctic Analog for Dilational Bands on Europa

    Science.gov (United States)

    Hurford, T. A.; Brunt, K. M.

    2014-01-01

    Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

  3. Comparison between analog and digital filters

    Directory of Open Access Journals (Sweden)

    Zoltan Erdei

    2010-12-01

    Full Text Available Digital signal processing(DSP is one of the most powerful technologies and will model science and engineering in the 21st century. Revolutionary changes have already been made in different areas of research such as communications, medical imaging, radar and sonar technology, high fidelity audio signal reproducing etc. Each of these fields developed a different signal processing technology with its own algorithms, mathematics and technology, Digital filters are used in two general directions: to separate mixed signals and to restore signals that were compromised in different modes. The objective of this paper is to compare some basic digital filters versus analog filters such as low-pass, high-pass, band-pass filters. Scientists and engineers comprehend that, in comparison with analog filters, digital filters can process the same signal in real-time with broader flexibility. This understanding is considered important to instill incentive for engineers to become interested in the field of DSP. The analysis of the results will be made using dedicated libraries in MATLAB and Simulink software, such as the Signal Processing Toolbox.

  4. Martian hillside gullies and icelandic analogs

    Science.gov (United States)

    Hartmann, William K.; Thorsteinsson, Thorsteinn; Sigurdsson, Freysteinn

    2003-04-01

    We report observations of Icelandic hillside gully systems that are near duplicates of gullies observed on high-latitude martian hillsides. The best Icelandic analogs involve basaltic talus slopes at the angle of repose, with gully formation by debris flows initiated by ground water saturation, and/or by drainage of water from upslope cliffs. We report not only the existence of Mars analog gullies, but also an erosional sequence of morphologic forms, found both on Mars and in Iceland. The observations support hypotheses calling for creation of martian gullies by aqueous processes. Issues remain whether the water in each case comes only from surficial sources, such as melting of ground ice or snow, or from underground sources such as aquifers that gain surface access in hillsides. Iceland has many examples of the former, but the latter mechanism is not ruled out. Our observations are consistent with the martian debris flow mechanism of F. Costard et al. (2001c, Science295, 110-113), except that classic debris flows begin at midslope more frequently than on Mars. From morphologic observations, we suggest that some martian hillside gully systems not only involve significant evolution by extended erosive activity, but gully formation may occur in episodes, and the time interval since the last episode is considerably less than the time interval needed to erase the gully through normal martian obliteration processes.

  5. Palytoxin and Analogs: Biological and Ecological Effects

    Directory of Open Access Journals (Sweden)

    Vítor Ramos

    2010-06-01

    Full Text Available Palytoxin (PTX is a potent marine toxin that was originally found in soft corals from tropical areas of the Pacific Ocean. Soon after, its occurrence was observed in numerous other marine organisms from the same ecological region. More recently, several analogs of PTX were discovered, remarkably all from species of the dinoflagellate genus Ostreopsis. Since these dinoflagellates are also found in other tropical and even in temperate regions, the formerly unsuspected broad distribution of these toxins was revealed. Toxicological studies with these compounds shows repeatedly low LD50 values in different mammals, revealing an acute toxic effect on several organs, as demonstrated by different routes of exposure. Bioassays tested for some marine invertebrates and evidences from environmental populations exposed to the toxins also give indications of the high impact that these compounds may have on natural food webs. The recognition of its wide distribution coupled with the poisoning effects that these toxins can have on animals and especially on humans have concerned the scientific community. In this paper, we review the current knowledge on the effects of PTX and its analogs on different organisms, exposing the impact that these toxins may have in coastal ecosystems.

  6. Metastatic Insulinoma Managed with Radiolabeled Somatostatin Analog

    Directory of Open Access Journals (Sweden)

    Ricardo Costa

    2013-01-01

    Full Text Available Insulinoma is a rare pancreatic neuroendocrine tumor. Overproduction of insulin and associated hypoglycemia are hallmark features of this disease. Diagnosis can be made through demonstration of hypoglycemia and elevated plasma levels of insulin or C-Peptide. Metastatic disease can be detected through computerized tomography (CT scans, magnetic resonance imaging (MRI, and positron emission tomography (PET/CT. Somatostatin receptor scintigraphy can be used not only to document metastatic disease but also as a predictive marker of the benefit from therapy with radiolabeled somatostatin analog. Unresectable metastatic insulinomas may present as a major therapeutic challenge for the treating physician. When feasible, resection is the mainstay of treatment. Prevention of hypoglycemia is a crucial goal of therapy for unresectable/metastatic tumors. Diazoxide, hydrochlorothiazide, glucagon, and intravenous glucose infusions have been used for glycemic control yielding temporary and inconsistent results. Sandostatin and its long-acting depot forms have occasionally been used in the treatment of Octreoscan-positive insulinomas. Herein, we report a case of metastatic insulinoma with very difficult glycemic control successfully treated with the radiolabeled somatostatin analog lutetium (177LU.

  7. Operational Lessons Learned from NASA Analog Missions

    Science.gov (United States)

    Arnold, Larissa S.

    2010-01-01

    vehicle and system capabilities are required to support the activities? How will the crew and the Earth-based mission control team interact? During the initial phases of manned planetary exploration, one challenge in particular is virtually the same as during the Apollo program: How can scientific return be maximized during a relatively short surface mission? Today, NASA is investigating solutions to these challenges by conducting analog missions. These Earth-based missions possess characteristics that are analogous to missions on the Moon or Mars. These missions are excellent for testing operational concepts, and the design, configuration, and functionality of spacesuits, robots, rovers, and habitats. Analog mission crews test specific techniques and procedures for surface field geology, biological sample collection, and planetary protection. The process of actually working an analog mission reveals a myriad of small details, which either contribute to or impede efficient operations, many of which would never have been thought about otherwise. It also helps to define the suite of tools, containers, and other small equipment that surface explorers will use. This paper focuses on how analog missions have addressed selected operational considerations for future planetary missions.

  8. Video signal processing system uses gated current mode switches to perform high speed multiplication and digital-to-analog conversion

    Science.gov (United States)

    Gilliland, M. G.; Rougelot, R. S.; Schumaker, R. A.

    1966-01-01

    Video signal processor uses special-purpose integrated circuits with nonsaturating current mode switching to accept texture and color information from a digital computer in a visual spaceflight simulator and to combine these, for display on color CRT with analog information concerning fading.

  9. Flow-induced noise simulation using detached eddy simulation and the finite element acoustic analogy method

    Directory of Open Access Journals (Sweden)

    Kai Liu

    2016-06-01

    Full Text Available Signals in long-distance pipes are complex due to flow-induced noise generated in special structure, and the computation of these noise sources is difficult and time-consuming. To address this problem, a hybrid method based on computational fluid dynamics and Lighthill’s acoustic analogy theory is proposed to simulate flow-induced noise, with the results showing that the method is sufficient for noise predictions. The proposed method computes the turbulent flow field using detached eddy simulation and then calculates turbulence-generated sound using the finite element acoustic analogy method, which solves acoustic sources as volume sources. The velocity field obtained in the detached eddy simulation computation provides the sound source through interpolation between the computational fluid dynamics and acoustic meshes. The hybrid method is validated and assessed by comparing data from the cavity in pipe and large eddy simulation results. The peak value of flow-induced noise calculated at the monitor point is in good agreement with experimental data available in the literature.

  10. Synthetic analogs of bacterial quorum sensors

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Rashi (Los Alamos, NM); Ganguly, Kumkum (Los Alamos, NM); Silks, Louis A. (Los Alamos, NM)

    2011-12-06

    Bacterial quorum-sensing molecule analogs having the following structures: ##STR00001## and methods of reducing bacterial pathogenicity, comprising providing a biological system comprising pathogenic bacteria which produce natural quorum-sensing molecule; providing a synthetic bacterial quorum-sensing molecule having the above structures and introducing the synthetic quorum-sensing molecule into the biological system comprising pathogenic bacteria. Further is provided a method of targeted delivery of an antibiotic, comprising providing a synthetic quorum-sensing molecule; chemically linking the synthetic quorum-sensing molecule to an antibiotic to produce a quorum-sensing molecule-antibiotic conjugate; and introducing the conjugate into a biological system comprising pathogenic bacteria susceptible to the antibiotic.

  11. Ultra Low-Power Analog Median Filters

    Directory of Open Access Journals (Sweden)

    A. Diaz-Sanchez

    2013-09-01

    Full Text Available The design and implementation of three analog median filter topologies, whose transistors operate in the deep weak-inversion region, is described. The first topology is a differential pairs array, in which drain currents are driven into two nodes in a differential fashion, while the second topology is based on a wide range OTA, which is used to maximize the dynamic range. Finally, the third topology uses three range-extended OTAs. The proposed weak-inversion filters were designed and fabricated in ON Semiconductor 0.5 micrometer technology through MOSIS. Experimental results of three-input fabricated prototypes for all three topologies are show, where power consumptions of 90nW in the first case, and 270nW in the other two cases can be noticed. A dual power supply +/-1.5 Volts were used.

  12. Atwood and Poggendorff: an insightful analogy

    DEFF Research Database (Denmark)

    Coelho, Ricardo; Borges, Paulo; Avelar Sotomaior Karam, Ricardo

    2016-01-01

    - librium provide us with the solution for a compound Atwood machine with the same bodies. This analogy is pedagogically useful because it illustrates a common strategy to transform a dynamic in a static situation improving stu- dents’ comprehension of Newton’s laws and equilibrium.......Atwood’s treatise, in which the Atwood machine appears, was published in 1784. About 70 years later, Poggendorff showed experimentally that the weight of an Atwood machine is reduced when it is brought to motion. In the present paper, a twofold connection between this experiment and the Atwood...... machine is established. Firstly, if the Poggendorff apparatus is taken as an ideal one, the equations of motion of the apparatus coincide with the equations of motion of the compound Atwood machine. Secondly, if the Poggendorff apparatus, which works as a lever, is rebalanced, the equations of this equi...

  13. Atwood and Poggendorff: an insightful analogy

    Science.gov (United States)

    Coelho, R. L.; Borges, P. F.; Karam, R.

    2016-11-01

    Atwood’s treatise, in which the Atwood machine appears, was published in 1784. About 70 years later, Poggendorff showed experimentally that the weight of an Atwood machine is reduced when it is brought to motion. In the present paper, a twofold connection between this experiment and the Atwood machine is established. Firstly, if the Poggendorff apparatus is taken as an ideal one, the equations of motion of the apparatus coincide with the equations of motion of the compound Atwood machine. Secondly, if the Poggendorff apparatus, which works as a lever, is rebalanced, the equations of this equilibrium provide us with the solution for a compound Atwood machine with the same bodies. This analogy is pedagogically useful because it illustrates a common strategy to transform a dynamic in a static situation improving students’ comprehension of Newton’s laws and equilibrium.

  14. Four-gate transistor analog multiplier circuit

    Science.gov (United States)

    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.

  15. On analog implementations of discrete neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.; Moore, K.R.

    1998-12-01

    The paper will show that in order to obtain minimum size neural networks (i.e., size-optimal) for implementing any Boolean function, the nonlinear activation function of the neutrons has to be the identity function. The authors shall shortly present many results dealing with the approximation capabilities of neural networks, and detail several bounds on the size of threshold gate circuits. Based on a constructive solution for Kolmogorov`s superpositions they will show that implementing Boolean functions can be done using neurons having an identity nonlinear function. It follows that size-optimal solutions can be obtained only using analog circuitry. Conclusions, and several comments on the required precision are ending the paper.

  16. Synthesis and biodistribution of radioiodinated nicotine analogs

    Energy Technology Data Exchange (ETDEWEB)

    Chan, S.M.; Basmadjian, G.P.; Marten, D.F.; Sadek, S.; Magarian, R.A.; Grunder, J.R.; Ice, R.D.

    1984-01-01

    The authors reported previously on the synthesis and biodistribution of radioiodinated 5-iodonicotine. In their continuous effort to search for a potential brain as well as adrenal medulla imaging agent, the authors synthesized four radioiodinated nicotine analogs. The labeled compounds were prepared by brominating nicotinic acid, and reacting the acylated product with the appropriate amines to give the respective amides which were then reduced with diborane to the amines. I-125 labeling was done by halogen exchange. Biodistribution studies performed in female Sprague-Dawley rats showed that all these compounds were taken up rapidly by the brain and the adrenal. The highest uptake of all these compounds in both organs occurred at 2 minutes after tail vein injections. The organ:blood ratios at 2 minutes and the T/sub 1/3/ (min.) of radioactivity in these organs were compared.

  17. Z~+(4430) and Analogous Heavy Flavor States

    Institute of Scientific and Technical Information of China (English)

    DING Gui-jun

    2009-01-01

    We have studied Z~+ (4430)as a D~* D_1 molecule from the quark model,state mixing effect is considered by solving the coupled channel Schr(o)dinger equation numerically.More precise measurements of Z~+ (4430)mass and width,partial wave analysis are helpful to understand its structure.If it lies below the D~* D_1 threshold,molecule interpretation with J~P=1~- is favored,and JP =0~- can not be ruled out.Otherwise Z~+ (4430)may be a virtual state with J~P=2~-.The analogous heavy flavor mesons Z~+_(bb) and Z~(++)_(bc) are considered as well,and the masses predicted in our model are in agreement with the predictions from the potential model and QCD sum rule.

  18. A Probabilistic Approach to Pronunciation by Analogy

    CERN Document Server

    Kujala, Janne V

    2011-01-01

    The relationship between written and spoken words is convoluted in languages with a deep orthography such as English and therefore it is difficult to devise explicit rules for generating the pronunciations for unseen words. Pronunciation by analogy (PbA) is a data-driven method of constructing pronunciations for novel words from concatenated segments of known words and their pronunciations. PbA performs relatively well with English and outperforms several other proposed methods. However, the best published word accuracy of 65.5% (for the 20,000 word NETtalk corpus) suggests there is much room for improvement in it. Previous PbA algorithms have used several different scoring strategies such as the product of the frequencies of the component pronunciations of the segments, or the number of different segmentations that yield the same pronunciation, and different combinations of these methods, to evaluate the candidate pronunciations. In this article, we instead propose to use a probabilistically justified scorin...

  19. X-Rays from Green Pea Analogs

    Science.gov (United States)

    Brorby, Matthew

    2014-09-01

    X-rays may have contributed to the heating and reionization of the IGM in the early universe. High mass X-ray binaries (HMXB) within small, low-metallicity galaxies are expected to be the main source of X-rays at this time. Since studying these high-redshift galaxies is currently impossible, we turn to local analogs that have the same properties the galaxies in the early are expected to have. A number of recent studies have shown an enhanced number of HMXBs in nearby low metallicity galaxies. We propose to observe a sample of metal-deficient luminous compact galaxies (LCG) in order to determine if the X-ray luminosity is enhanced relative to SFR, thereby providing further evidence to the importance of X-rays in the early universe.

  20. Analog circuit for controlling acoustic transducer arrays

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, Douglas S. (Cedar Crest, NM)

    1991-01-01

    A simplified ananlog circuit is presented for controlling electromechanical transducer pairs in an acoustic telemetry system. The analog circuit of this invention comprises a single electrical resistor which replaces all of the digital components in a known digital circuit. In accordance with this invention, a first transducer in a transducer pair of array is driven in series with the resistor. The voltage drop across this resistor is then amplified and used to drive the second transducer. The voltage drop across the resistor is proportional and in phase with the current to the transducer. This current is approximately 90 degrees out of phase with the driving voltage to the transducer. This phase shift replaces the digital delay required by the digital control circuit of the prior art.

  1. Analog model for an expanding universe

    CERN Document Server

    Weinfurtner, S E C

    2004-01-01

    Over the last few years numerous papers concerning analog models for gravity have been published. It was shown that the dynamical equation of several systems (e.g. Bose-Einstein condensates with a sink or a vortex) have the same wave equation as light in a curved-space (e.g. black holes). In the last few months several papers were released which deal with simulations of the universe. In this article the de-Sitter universe will be compared with a freely expanding three-dimensional spherical Bose-Einstein condensate. Initially the condensate is in a harmonic trap, which suddenly will be switched off. At the same time a small perturbation will be injected in the center of the condensate cloud. The motion of the perturbation in the expanding condensate will be discussed, and after some transformations the similarity to an expanding universe will be shown.

  2. Analogies and metaphors in clinical medicine.

    Science.gov (United States)

    Masukume, Gwinyai; Zumla, Alimuddin

    2012-02-01

    Medicine is traditionally known as an 'art', and not an exact 'science'. Medical images of clinical signs and pathology were communicated through 'metaphors' in the 19th and early 20th centuries to make recognition easier in anticipation of the clinical counterpart when encountered in medical practice. They have served as teaching aids, enhancing memory retention for medical students, nurses and doctors and have withstood the test of time. Standard medical textbooks contain metaphors that have become entrenched in teaching, learning and examining in medical schools and hospitals worldwide. The continued use of metaphors has given rise to an ongoing debate, particularly in Africa, due to the usage of inappropriate or unfamiliar metaphors which are not locally or culturally relevant. Despite this, medical analogies will no doubt continue to be useful for medical education, clinical practice and 'aide memoirs' for examinations, and bring light humour, for a long time to come.

  3. Disease Resistance Gene Analogs (RGAs in Plants

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Sekhwal

    2015-08-01

    Full Text Available Plants have developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs, as resistance (R gene candidates, have conserved domains and motifs that play specific roles in pathogens’ resistance. Well-known RGAs are nucleotide binding site leucine rich repeats, receptor like kinases, and receptor like proteins. Others include pentatricopeptide repeats and apoplastic peroxidases. RGAs can be detected using bioinformatics tools based on their conserved structural features. Thousands of RGAs have been identified from sequenced plant genomes. High-density genome-wide RGA genetic maps are useful for designing diagnostic markers and identifying quantitative trait loci (QTL or markers associated with plant disease resistance. This review focuses on recent advances in structures and mechanisms of RGAs, and their identification from sequenced genomes using bioinformatics tools. Applications in enhancing fine mapping and cloning of plant disease resistance genes are also discussed.

  4. Analog VLSI neural network integrated circuits

    Science.gov (United States)

    Kub, F. J.; Moon, K. K.; Just, E. A.

    1991-01-01

    Two analog very large scale integration (VLSI) vector matrix multiplier integrated circuit chips were designed, fabricated, and partially tested. They can perform both vector-matrix and matrix-matrix multiplication operations at high speeds. The 32 by 32 vector-matrix multiplier chip and the 128 by 64 vector-matrix multiplier chip were designed to perform 300 million and 3 billion multiplications per second, respectively. An additional circuit that has been developed is a continuous-time adaptive learning circuit. The performance achieved thus far for this circuit is an adaptivity of 28 dB at 300 KHz and 11 dB at 15 MHz. This circuit has demonstrated greater than two orders of magnitude higher frequency of operation than any previous adaptive learning circuit.

  5. Analogy between fluid cavitation and fracture mechanics

    Science.gov (United States)

    Hendricks, R. C.; Mullen, R. L.; Braun, M. J.

    1983-01-01

    When the stresses imposed on a fluid are sufficiently large, rupture or cavitation can occur. Such conditions can exist in many two-phase flow applications, such as the choked flows, which can occur in seals and bearings. Nonspherical bubbles with large aspect ratios have been observed in fluids under rapid acceleration and high shear fields. These bubbles are geometrically similar to fracture surface patterns (Griffith crack model) existing in solids. Analogies between crack growth in solid and fluid cavitation are proposed and supported by analysis and observation (photographs). Healing phenomena (void condensation), well accepted in fluid mechanics, have been observed in some polymers and hypothesized in solid mechanics. By drawing on the strengths of the theories of solid mechanics and cavitation, a more complete unified theory can be developed.

  6. Scattering by interstellar graphite dust analog

    Science.gov (United States)

    Ahmed, Gazi A.; Gogoi, Ankur

    2014-10-01

    The analysis of optical scattering data of interstellar carbonaceous graphite dust analog at 543.5 nm, 594.5 nm and 632.8 nm laser wavelengths by using an original laboratory light scattering setup is presented. The setup primarily consisted of a laser source, optical units, aerosol sprayer, data acquisition system and associated instrumentation. The instrument measured scattered light signals from 10° to 170° in steps of 1°. The results of the measurements of the volume scattering function β(θ) and degree of linear polarization P(θ) of the carbonaceous graphite dust particles that were sprayed in front of the laser beam by using an aerosol sprayer were subsequently compared with theoretically generated Mie plots with estimated parameters.

  7. A QCD analogy for quantum gravity

    CERN Document Server

    Holdom, Bob

    2015-01-01

    Quadratic gravity presents us with a renormalizable, asymptotically free theory of quantum gravity. When its couplings grow strong at some scale, as in QCD, then this strong scale sets the Planck mass. QCD has a gluon that does not appear in the physical spectrum. Quadratic gravity has a spin-2 ghost that we conjecture does not appear in the physical spectrum. We discuss how the QCD analogy leads to this conjecture and to the emergence of general relativity. Certain aspects of the QCD path integral and its measure could also be similar for quadratic gravity. With the addition of the Einstein-Hilbert term, quadratic gravity has a dimensionful parameter that seems to control a quantum phase transition and the size of a mass gap in the strong phase.

  8. Integrated Circuits for Analog Signal Processing

    CERN Document Server

    2013-01-01

      This book presents theory, design methods and novel applications for integrated circuits for analog signal processing.  The discussion covers a wide variety of active devices, active elements and amplifiers, working in voltage mode, current mode and mixed mode.  This includes voltage operational amplifiers, current operational amplifiers, operational transconductance amplifiers, operational transresistance amplifiers, current conveyors, current differencing transconductance amplifiers, etc.  Design methods and challenges posed by nanometer technology are discussed and applications described, including signal amplification, filtering, data acquisition systems such as neural recording, sensor conditioning such as biomedical implants, actuator conditioning, noise generators, oscillators, mixers, etc.   Presents analysis and synthesis methods to generate all circuit topologies from which the designer can select the best one for the desired application; Includes design guidelines for active devices/elements...

  9. Positons: slowly diminishing analogs of solitons

    CERN Document Server

    Matveev, V B

    2002-01-01

    The introduction to the theory of positons is presented. The positons are the remote-acting analogues of solitons and represent slowly diminishing and oscillating solitons of the nonlinear integrated equations of KdV type. The positon and soliton-positon solutions of the KdV equation were for the first time obtained and analyzed about 10 years ago and thereafter designed for a number of other models: mKdV, Toda chains, NSch, sn-Gordon equation and its lattice analog. By the proper selection of the scattering data the single positon and multipositon potentials are characterized by the remarkable property: the corresponding reflection coefficient is equal to zero and the transition coefficient is equal to one (the latter property, as it is known, has no place for the standard short-acting nonreflection potentials

  10. 23rd workshop on Advances in Analog Circuit Design

    CERN Document Server

    Baschirotto, Andrea; Makinwa, Kofi

    2015-01-01

    This book is based on the 18 tutorials presented during the 23rd workshop on Advances in Analog Circuit Design.  Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, serving as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.    • Includes coverage of high-performance analog-to-digital and digital to analog converters, integrated circuit design in scaled technologies, and time-domain signal processing; • Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; • Presents material in a tutorial-based format.

  11. [Analogies between the thymus and epidermis].

    Science.gov (United States)

    De Panfilis, G

    1990-11-01

    In this paper, similarities between epidermis and thymus are reviewed. Both epidermis and thymus deal with an epithelial stroma harbouring dendritic cells, which are bone-marrow derived. Both epithelia are keratinized, and a map can be constructed illustrating histo-topographic and antigenic similarities between thymic epithelial cells distributed in various thymic zones (i.e. subcapsular cortex, outer cortex, inner cortex, medulla, outer layers of Hassall's bodies, inner layers of Hassall's bodies) and keratinocytes of different epidermal layers. By contrast, a possible similarity between thymocytes and Langerhans cells is not so easy to demonstrate, although both cell types are CD1 positive. Rather, in our opinion a comparison is preferable of thymocytes to Thy-1 positive dendritic epidermal cells, due to morphological, antigenic, functional and especially lineage similarities. Similarities between thymus and epidermis are clearly important dealing with analogous molecular interactions, namely, thymic epithelial cells/thymocytes versus keratinocytes/T-lymphocytes. Indeed, our recent investigations demonstrated that a subset of keratinocytes is ICAM-1 positive, and the whole keratinocyte population is LFA-3 positive. Since the interaction thymic epithelial cells (ICAM-1 and LFA-3 positive)/thymocytes (LFA-1 and CD2 positive) has been shown to be necessary for promotion of activation and maturation of thymocytes, the interaction keratinocytes (ICAM-1 and LFA-3 positive, as we demonstrated)/T-lymphocytes (LFA-1 and CD2 positive as well) might be, by analogy, important not only for the "homing" of T-lymphocytes within the epidermis, but also for the epidermis being considered a peripheral inductive site for T-cell activation and maturation.

  12. Optical analog-to-digital converter

    Science.gov (United States)

    Evanchuk, Vincent L. (Inventor)

    1984-01-01

    A method and apparatus for converting the intensity of an unknown optical signal (B) into an electrical signal in digital form utilizes two elongated optical attenuators (11, 13), one for the unknown optical signal from a source (10) and one for a known optical signal (A) from a variable source (12), a plurality of photodetectors (e.g., 17, 18) along each attenuator for detecting the intensity of the optical signals, and a plurality of comparators (e.g., 21) connected to the photodetectors in pairs to determine at what points being compared the attenuated known signal equals the attenuated unknown signal. The intensity of the unknown relative to the known is thus determined by the output of a particular comparator. That output is automatically encoded to a relative intensity value in digital form through a balancing feedback control (24) and encoder (23). The digital value may be converted to analog form in a D-to-A converter (27) and used to vary the source of the known signal so that the attenuated intensity of the known signal at a predetermined point (comparator 16) equals the attenuated intensity of the unknown signal at the predetermined point of comparison. If the known signal is then equal to the unknown, there is verification of the analog-to-digital conversion being complete. Otherwise the output of the comparator indicating equality at some other point along the attenuators will provide an output which is encoded and added, through an accumulator comprised of a register (25) and an adder (26), to a previous relative intensity value thereby to further vary the intensity of the known signal source. The steps are repeated until full conversion is verified.

  13. Computer Aided Design Tools for Extreme Environment Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to provide Computer Aided Design (CAD) tools for radiation-tolerant, wide-temperature-range digital, analog, mixed-signal, and radio-frequency...

  14. Analog circuit design a tutorial guide to applications and solutions

    CERN Document Server

    Williams, Jim

    2011-01-01

    * Covers the fundamentals of linear/analog circuit and system design to guide engineers with their design challenges. * Based on the Application Notes of Linear Technology, the foremost designer of high performance analog products, readers will gain practical insights into design techniques and practice. * Broad range of topics, including power management tutorials, switching regulator design, linear regulator design, data conversion, signal conditioning, and high frequency/RF design. * Contributors include the leading lights in analog design, Robert Dobkin, Jim Willia

  15. Synthesis and biological activity of nifuroxazide and analogs. II.

    Science.gov (United States)

    Tavares, L C; Chisté, J J; Santos, M G; Penna, T C

    1999-09-01

    Nifuroxazyde and six analogs were synthesized by varying the substitute from the para-position of the benzenic ring and the heteroatom of the heterocyclic ring. The MIC of seven resultant compounds was determined by serial dilutions, testing the ATCC 25923 strain of Staphylococcus aureus. A significant increase in the anti-microbial activity of thyophenic analogs, as compared with furanic and pyrrholic analogs, was observed. In addition, unlike the cyano and hydroxyl groups, the acetyl group promoted anti-microbial activity.

  16. Novel C-1 Substituted Cocaine Analogs Unlike Cocaine or Benztropine

    OpenAIRE

    Reith, Maarten E. A.; Ali, Solav; Hashim, Audrey; Sheikh, Imran S.; Theddu, Naresh; Gaddiraju, Narendra V.; Mehrotra, Suneet; Schmitt, Kyle C.; Murray, Thomas F.; Sershen, Henry; Unterwald, Ellen M.; Davis, Franklin A.

    2012-01-01

    Despite a wealth of information on cocaine-like compounds, there is no information on cocaine analogs with substitutions at C-1. Here, we report on (R)-(−)-cocaine analogs with various C-1 substituents: methyl (2), ethyl (3), n-propyl (4), n-pentyl (5), and phenyl (6). Analog 2 was equipotent to cocaine as an inhibitor of the dopamine transporter (DAT), whereas 3 and 6 were 3- and 10-fold more potent, respectively. None of the analogs, however, stimulated mouse locomotor activity, in contrast...

  17. Physical analogy between continuum thermodynamics and classical mechanics.

    Science.gov (United States)

    Umantsev, Alex

    2004-01-01

    The main focus of this paper is the profound physical analogy between a continuum thermodynamical system, which evolves with relaxation under (possibly) nonisothermal conditions, and a classical mechanical system of a few interacting particles moving with dissipation in (possibly), time-dependent nonconservative fields. This analogy is applied to the problem of phase transitions in a one-dimensional thermodynamic system. The thermomechanical analogy stems from the validity of variational methods in mechanics and thermodynamics and allows for a different interpretation of the dynamical selection principle in the theory of pattern formation. This physical analogy is very helpful for understanding different nonlinear thermodynamic phenomena and for developing intuition in numerical simulations.

  18. CRC handbook of neurohypophyseal hormone analogs. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Jost, K.; Lebl, M.; Brtnik, F.

    1987-01-01

    This book is discussed in two parts. The Part 1 discusses the: Prohormones and Hormonogens of Neuro-hypophyseal Hormones, Analogs with Inhibitory properties. Analogs with Dissociated and/or High activities. Introduction. Uterotonic Activity. Galactogogic Activity. Pressor Activity. Antidiuretic Activity. References. Part 2 discusses the Other Important Activities. CNS Activities. Corticotropin- and ..beta..-Entriuretic Action. Natriferic Action. References. Practical Use in Human and Veterinary Medicine. Introduction. Methyloxytocin. Deamino-Oxytocin. Cargutocin. Glypressin. Octapressin. Desmopressin. Analogs Clinically Tried But Not Introduced into Production and Routine Clinical Practice. References. Tables of Analogs and Index.

  19. Non-analog Monte Carlo estimators for radiation momentum deposition

    Energy Technology Data Exchange (ETDEWEB)

    Densmore, Jeffery D [Los Alamos National Laboratory; Hykes, Joshua M [Los Alamos National Laboratory

    2008-01-01

    The standard method for calculating radiation momentum deposition in Monte Carlo simulations is the analog estimator, which tallies the change in a particle's momentum at each interaction with the matter. Unfortunately, the analog estimator can suffer from large amounts of statistical error. In this paper, we present three new non-analog techniques for estimating momentum deposition. Specifically, we use absorption, collision, and track-length estimators to evaluate a simple integral expression for momentum deposition that does not contain terms that can cause large amounts of statistical error in the analog scheme. We compare our new non-analog estimators to the analog estimator with a set of test problems that encompass a wide range of material properties and both isotropic and anisotropic scattering. In nearly all cases, the new non-analog estimators outperform the analog estimator. The track-length estimator consistently yields the highest performance gains, improving upon the analog-estimator figure of merit by factors of up to two orders of magnitude.

  20. 25th workshop on Advances in Analog Circuit Design

    CERN Document Server

    Harpe, Pieter; Makinwa, Kofi

    2017-01-01

    This book is based on the 18 tutorials presented during the 25th workshop on Advances in Analog Circuit Design. Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, including low-power and energy-efficient analog electronics, with specific contributions focusing on the design of continuous-time sigma-delta modulators, automotive electronics, and power management. This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.

  1. Utilizing multiple state variables to improve the dynamic range of analog switching in a memristor

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, YeonJoo; Kim, Sungho; Lu, Wei D., E-mail: wluee@eecs.umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 48109 (United States)

    2015-10-26

    Memristors and memristive systems have been extensively studied for data storage and computing applications such as neuromorphic systems. To act as synapses in neuromorphic systems, the memristor needs to exhibit analog resistive switching (RS) behavior with incremental conductance change. In this study, we show that the dynamic range of the analog RS behavior can be significantly enhanced in a tantalum-oxide-based memristor. By controlling different state variables enabled by different physical effects during the RS process, the gradual filament expansion stage can be selectively enhanced without strongly affecting the abrupt filament length growth stage. Detailed physics-based modeling further verified the observed experimental effects and revealed the roles of oxygen vacancy drift and diffusion processes, and how the diffusion process can be selectively enhanced during the filament expansion stage. These findings lead to more desirable and reliable memristor behaviors for analog computing applications. Additionally, the ability to selectively control different internal physical processes demonstrated in the current study provides guidance for continued device optimization of memristor devices in general.

  2. Analog-digital converters for industrial applications including an introduction to digital-analog converters

    CERN Document Server

    Ohnhäuser, Frank

    2015-01-01

    This book offers students and those new to the topic of analog-to-digital converters (ADCs) a broad introduction, before going into details of the state-of-the-art design techniques for SAR and DS converters, including the latest research topics, which are valuable for IC design engineers as well as users of ADCs in applications. The book then addresses important topics, such as correct connectivity of ADCs in an application, the verification, characterization and testing of ADCs that ensure high-quality end products. Analog-to-digital converters are the central element in any data processing system and regulation loops such as modems or electrical motor drives. They significantly affect the performance and resolution of a system or end product. System development engineers need to be familiar with the performance parameters of the converters and understand the advantages and disadvantages of the various architectures. Integrated circuit development engineers have to overcome the problem of achieving high per...

  3. The mixed analog/digital shaper of the LHCb preshower

    CERN Document Server

    Lecoq, J; Cornat, R; Perret, P; Trouilleau, C

    2001-01-01

    The LHCb preshower signals show so many fluctuations at low energy that a classical shaping is not usable at all. Thanks to the fact that the fraction of the collected energy during a whole LHC beam crossing time is 85%, we studied the special solution we presented at Snowmass 1999 workshop. This solution consists of 2 interleaved fast integrators, one being in integrate mode when the other is digitally reset. Two track-and-hold systems and an analog multiplexer are used to give at the output 85% of the signal plus 15% of the previous one. These 15% are digitally computed from the previous sample, and subtracted. A completely new design of this solution had to be made. This new design is described, including new methods to decrease the supply voltage and the noise, as well as to increase the quality of the reset and the linearity. An output stage, consisting of an AB class push-pull using only NPN transistors is also described. Laboratory and beam test results are given. (5 refs).

  4. ANALOG I/O MODULE TEST SYSTEM BASED ON EPICS CA PROTOCOL AND ACTIVEX CA INTERFACE

    Energy Technology Data Exchange (ETDEWEB)

    YENG,YHOFF,L.

    2003-10-13

    Analog input (ADC) and output (DAC) modules play a substantial role in device level control of accelerator and large experiment physics control system. In order to get the best performance some features of analog modules including linearity, accuracy, crosstalk, thermal drift and so on have to be evaluated during the preliminary design phase. Gain and offset error calibration and thermal drift compensation (if needed) may have to be done in the implementation phase as well. A natural technique for performing these tasks is to interface the analog VO modules and GPIB interface programmable test instruments with a computer, which can complete measurements or calibration automatically. A difficulty is that drivers of analog modules and test instruments usually work on totally different platforms (vxworks VS Windows). Developing new test routines and drivers for testing instruments under VxWorks (or any other RTOS) platform is not a good solution because such systems have relatively poor user interface and developing such software requires substantial effort. EPICS CA protocol and ActiveX CA interface provide another choice, a PC and LabVIEW based test system. Analog 110 module can be interfaced from LabVIEW test routines via ActiveX CA interface. Test instruments can be controlled via LabVIEW drivers, most of which are provided by instrument vendors or by National Instruments. Labview also provides extensive data analysis and process functions. Using these functions, users can generate powerful test routines very easily. Several applications built for Spallation Neutron Source (SNS) Beam Loss Monitor (BLM) system are described in this paper.

  5. Liberation of quarks and spinons on domain walls: analogies between gauge theories and quantum magnets

    CERN Document Server

    Sulejmanpasic, Tin; Sandvik, Anders; Unsal, Mithat

    2016-01-01

    In a spontaneously dimerized quantum antiferromagnet (a valence-bond-solid, VBS) in two or three dimensions, elementary spin-1/2 excitations (spinons) are confined by strings akin to the strings confining quarks in non-abelian gauge theories. The VBS has multiple degenerate ground states (vacua) and domain walls between regions of inequivalent vacua. Here we demonstrate that, if the number of vacua is two, the spinons become liberated (deconfined) on the domain wall. This is in close analogy to supersymmetric gauge theories, where quarks deconfine on domain walls separating two vacua, as first conjecture by Rey and Witten. We show that the confinement mechanism in the VBS and Super-Yang-Mills theory are identical in certain regimes. This remarkable close analogy opens doors to improving our understanding of confinement by computational and experimental studies in quantum magnetism. As an illustration, we present a numerical demonstration of spinon deconfinement on domain walls in a two-dimensional quantum mag...

  6. The design, fabrication, and test of a new VLSI hybrid analog-digital neural processing element

    Science.gov (United States)

    Deyong, Mark R.; Findley, Randall L.; Fields, Chris

    1992-01-01

    A hybrid analog-digital neural processing element with the time-dependent behavior of biological neurons has been developed. The hybrid processing element is designed for VLSI implementation and offers the best attributes of both analog and digital computation. Custom VLSI layout reduces the layout area of the processing element, which in turn increases the expected network density. The hybrid processing element operates at the nanosecond time scale, which enables it to produce real-time solutions to complex spatiotemporal problems found in high-speed signal processing applications. VLSI prototype chips have been designed, fabricated, and tested with encouraging results. Systems utilizing the time-dependent behavior of the hybrid processing element have been simulated and are currently in the fabrication process. Future applications are also discussed.

  7. The interplay of conflict and analogy in multidisciplinary teams.

    Science.gov (United States)

    Paletz, Susannah B F; Schunn, Christian D; Kim, Kevin H

    2013-01-01

    Creative teamwork in multidisciplinary teams is a topic of interest to cognitive psychologists on the one hand, and to both social and organizational psychologists on the other. However, the interconnections between cognitive and social layers have been rarely explored. Drawing on mental models and dissonance theories, the current study takes a central variable studied by cognitive psychologists-analogy-and examines its relationship to a central variable examined by social psychologists-conflict. In an observational, field study, over 11h of audio-video data from conversations of the Mars Exploration Rover scientists were coded for different types of analogy and micro-conflicts that reveal the character of underlying psychological mechanisms. Two different types of time-lagged logistic models applied to these data revealed asymmetric patterns of associations between analogy and conflict. Within-domain analogies, but not within-discipline or outside-discipline analogies, preceded science and work process conflicts, suggesting that in multidisciplinary teams, representational gaps in very close domains will be more likely to spark conflict. But analogies also occurred in reaction to conflict: Process and negative conflicts, but not task conflicts, preceded within-discipline analogies, but not to within-domain or outside-discipline analogies. This study demonstrates ways in which cognition can be bidirectionally tied to social processes and discourse.

  8. Analog circuit design techniques at 0.5V

    CERN Document Server

    Chatterjee, Shouri; Stanic, Nebojša

    2010-01-01

    This book tackles challenges for the design of analog integrated circuits that operate from ultra-low power supply voltages (down to 0.5V). Coverage demonstrates the signal processing circuit and circuit biasing approaches through the design of operational transconductance amplifiers (OTAs). These amplifiers are then used to build analog system functions including continuous time filter and a sample and hold amplifier.

  9. Analogical Reasoning in the Classroom: Insights from Cognitive Science

    Science.gov (United States)

    Vendetti, Michael S.; Matlen, Bryan J.; Richland, Lindsey E.; Bunge, Silvia A.

    2015-01-01

    Applying knowledge from one context to another is a notoriously difficult problem, both for children and adults, but lies at the heart of educational endeavors. Analogical reasoning is a cognitive underpinning of the ability to notice and draw similarities across contexts. Reasoning by analogy is especially challenging for students, who must…

  10. Q-Analogies: A Test of Quantitative Reasoning.

    Science.gov (United States)

    Chase, Clinton I.; Johnson, Judith J.

    The initial steps necessary for constructing an analogies test are described. Basic mathematics being the context, the aim of the test is to predict student performance in research statistics courses characteristic of graduate education and social science programs. Items involving analogies in a quantitative context were built, sorted into two…

  11. Analog modeling of transient moisture flow in unsaturated soil

    NARCIS (Netherlands)

    Wind, G.P.

    1979-01-01

    Hydraulic and electronic analog models are developed for the simulation of moisture flow and accumulation in unsaturated soil. The analog models are compared with numerical models and checked with field observations. Application of soil physical knowledge on a soil technological problem by means of

  12. Physical properties and structure of enzymatically synthesized amylopectin analogs

    NARCIS (Netherlands)

    Ciric, Jelena; Woortman, Albert J. J.; Gordiichuk, Pavlo; Stuart, Marc C. A.; Loos, Katja

    2013-01-01

    The mechanism of the enzymatic polymerization of amylopectin analogs with phosphorylase b and glycogen branching enzyme is very intriguing. Recently, size exclusion chromatography with multi-detection of enzymatically synthesized amylopectin analogs in combination with MALDI-ToF MS analysis of enzym

  13. SEAS: A simulated evolution approach for analog circuit synthesis

    NARCIS (Netherlands)

    Ning, Zhen-Qiu; Mouthaan, Ton; Wallinga, Hans

    1991-01-01

    The authors present a simulated evolution approach for analog circuit synthesis based on an analogy with the natural selection process in biological environments and on the iterative improvements in solving engineering problems. A prototype framework based on this idea, called SEAS, has been impleme

  14. Analog capacitance ROM with IGFET bucket-brigade shift register

    DEFF Research Database (Denmark)

    Bruun, Erik; Olesen, Ole

    1975-01-01

    A new type of monolithic analog read-out memory is described. It consists of a memory element and associated on-chip readout circuitry. The memory can be used for storing sample values of time-varying analog signals. The memory element is a matrix of MOS capacitors, preprogrammed in size by a spe...

  15. Using Analogies to Prevent Misconceptions about Chemical Equilibrium

    Science.gov (United States)

    Sahin Pekmez, Esin

    2010-01-01

    The main purpose of this study was to find the effectiveness of using analogies to prevent misconceptions about chemical equilibrium. Nineteen analogies, which were based on dynamic aspects of chemical equilibrium and application of Le Chatelier's principle, were developed. The participations of this study consisted of 11th grade students (n: 151)…

  16. Stereoselective synthesis of nicotinamide beta-riboside and nucleoside analogs.

    Science.gov (United States)

    Franchetti, Palmarisa; Pasqualini, Michela; Petrelli, Riccardo; Ricciutelli, Massimo; Vita, Patrizia; Cappellacci, Loredana

    2004-09-20

    The beta-anomers of N-ribofuranosylnicotine-3-carboxamide (beta-NAR) and its nicotinic acid analog (beta-NaR) were obtained by stereoselective synthesis via glycosylation of the presilylated bases under Vorbruggen's protocol. A NAR analog, methylated in position 3 of the ribosylic moiety, is also reported.

  17. Molecular interactions between (--epigallocatechin gallate analogs and pancreatic lipase.

    Directory of Open Access Journals (Sweden)

    Shihui Wang

    Full Text Available The molecular interactions between pancreatic lipase (PL and four tea polyphenols (EGCG analogs, like (--epigallocatechin gallate (EGCG, (--gallocatechin gallate (GCG, (--epicatechin gallate (ECG, and (--epigallocatechin (EC, were studied from PL activity, conformation, kinetics and thermodynamics. It was observed that EGCG analogs inhibited PL activity, and their inhibitory rates decreased by the order of EGCG>GCG>ECG>EC. PL activity at first decreased rapidly and then slowly with the increase of EGCG analogs concentrations. α-Helix content of PL secondary structure decreased dependent on EGCG analogs concentration by the order of EGCG>GCG>ECG>EC. EGCG, ECG, and EC could quench PL fluorescence both dynamically and statically, while GCG only quenched statically. EGCG analogs would induce PL self-assembly into complexes and the hydrodynamic radii of the complexes possessed a close relationship with the inhibitory rates. Kinetics analysis showed that EGCG analogs non-competitively inhibited PL activity and did not bind to PL catalytic site. DSC measurement revealed that EGCG analogs decreased the transition midpoint temperature of PL enzyme, suggesting that these compounds reduced PL enzyme thermostability. In vitro renaturation through urea solution indicated that interactions between PL and EGCG analogs were weak and non-covalent.

  18. Insulin analogs and cancer: A note of caution

    NARCIS (Netherlands)

    J.A.M.J.L. Janssen (Joseph); A.J. Varewijck (Aimee)

    2014-01-01

    textabstractIn view of the lifelong exposure and large patient populations involved, insulin analogs with an increased mitogenic effect in comparison to human insulin may potentially constitute a major health problem, since these analogs may possibly induce the growth of pre-existing neoplasms. At p

  19. 47 CFR 74.705 - TV broadcast analog station protection.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false TV broadcast analog station protection. 74.705... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.705 TV broadcast analog station protection. (a) The TV...

  20. Radiolabeled somatostatin analogs in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, M.L.; Kolan, H.; Li, J.; Wiaderkiewicz, R.; Pallela, V.R.; Duggaraju, R.; Schally, A.V

    1997-01-01

    Vapreotide (RC-160), a somatostatin analog, was labeled with {sup 99m}Tc by a direct method and also by using CPTA [1,4,8,11-tetraazacyclotetradecane] as a bifunctional chelating agent. The labeled compounds were evaluated in nude mice bearing experimental human prostate cancers. In these studies, {sup 111}In-DTPA-D-Phe-Octreotide ({sup 111}In-DTPA-octreotide) served as a standard and {sup 99m}Tc-oxytocin as a receptor-non-specific control. {sup 99m}Tc-octreotide was also used. The 24 htumor uptake of {sup 99m}Tc-RC-160 was nearly 400% higher, (p < 0.05), than that of {sup 111}In-DTPA-octreotide and diminished upon receptor blocking. In all tissues except the kidneys, the uptake of {sup 99m}Tc-RC-160 was also higher than that of {sup 111}In-DTPA-octreotide. The uptake of {sup 99m}Tc-RC-160 was influenced by the amount of peptide injected and the best tumor/muscle and tumor/blood ratios were obtained when only one {mu}g of the peptide (200 Ci/mmol) was administered.

  1. Serial Pixel Analog-to-Digital Converter

    Energy Technology Data Exchange (ETDEWEB)

    Larson, E D

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and “one-hot” counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  2. The MARS2013 Mars analog mission.

    Science.gov (United States)

    Groemer, Gernot; Soucek, Alexander; Frischauf, Norbert; Stumptner, Willibald; Ragonig, Christoph; Sams, Sebastian; Bartenstein, Thomas; Häuplik-Meusburger, Sandra; Petrova, Polina; Evetts, Simon; Sivenesan, Chan; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Foresta, Luca; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Stadler, Andrea; Stummer, Florian; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Turetschek, Thomas; Winter, Egon; Zanella-Kux, Katja

    2014-05-01

    We report on the MARS2013 mission, a 4-week Mars analog field test in the northern Sahara. Nineteen experiments were conducted by a field crew in Morocco under simulated martian surface exploration conditions, supervised by a Mission Support Center in Innsbruck, Austria. A Remote Science Support team analyzed field data in near real time, providing planning input for the management of a complex system of field assets; two advanced space suit simulators, four robotic vehicles, an emergency shelter, and a stationary sensor platform in a realistic work flow were coordinated by a Flight Control Team. A dedicated flight planning group, external control centers for rover tele-operations, and a biomedical monitoring team supported the field operations. A 10 min satellite communication delay and other limitations pertinent to human planetary surface activities were introduced. The fields of research for the experiments were geology, human factors, astrobiology, robotics, tele-science, exploration, and operations research. This paper provides an overview of the geological context and environmental conditions of the test site and the mission architecture, in particular the communication infrastructure emulating the signal travel time between Earth and Mars. We report on the operational work flows and the experiments conducted, including a deployable shelter prototype for multiple-day extravehicular activities and contingency situations.

  3. Amino acid analogs for tumor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, Mark M. (Atlanta, GA); Shoup, Timothy (Decatur, GA)

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  4. Amino acid analogs for tumor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, Mark M. (Atlanta, GA); Shoup, Timothy (Decatur, GA)

    1998-10-06

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  5. Amino acid analogs for tumor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, M.M.; Shoup, T.

    1998-10-06

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

  6. Somatostatin analog treatment of acromegaly: new aspects.

    Science.gov (United States)

    Lamberts, S W; del Pozo, E

    1988-01-01

    Ten acromegalics received daily doses of 200-300 micrograms of a long-acting somatostatin analog, SMS 201-995 (Sandostatin, SMS), for an average of 64 weeks. Basal mean GH values of 44 +/- (SE) 7.8 ng/ml had fallen into the normal range at the end of the observation period (mean 64 weeks). This effect was accompanied by a substantial drop in somatomedin-C values. Reduction of pituitary tumor size could be documented in 3 of 6 patients. Whereas SMS did not affect high plasma PRL in 4 microprolactinoma patients, lactotrophs turned sensitive to this agent in mixed GH/PRL tumors. In a comparative study between SMS and bromocriptine, the former normalized circulating GH in 10 of 17 acromegalics in an acute trial, whereas bromocriptine was effective in only 5. A combination of both substances was effective in 2 of 3 patients who were insensitive to single drug administration. Cultures of GH-secreting tumor cells showed a statistically significant hormone decrease in the medium when exposed to SMS. However, in some instances, a diminution of the GH contents of the tumor cells was also observed, presumably as the basis for intracellular breakdown and clinical tumor shrinkage.

  7. Natural CO2 Analogs for Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Scott H. Stevens; B. Scott Tye

    2005-07-31

    The report summarizes research conducted at three naturally occurring geologic CO{sub 2} fields in the US. The fields are natural analogs useful for the design of engineered long-term storage of anthropogenic CO{sub 2} in geologic formations. Geologic, engineering, and operational databases were developed for McElmo Dome in Colorado; St. Johns Dome in Arizona and New Mexico; and Jackson Dome in Mississippi. The three study sites stored a total of 2.4 billion t (46 Tcf) of CO{sub 2} equivalent to 1.5 years of power plant emissions in the US and comparable in size with the largest proposed sequestration projects. The three CO{sub 2} fields offer a scientifically useful range of contrasting geologic settings (carbonate vs. sandstone reservoir; supercritical vs. free gas state; normally pressured vs. overpressured), as well as different stages of commercial development (mostly undeveloped to mature). The current study relied mainly on existing data provided by the CO{sub 2} field operator partners, augmented with new geochemical data. Additional study at these unique natural CO{sub 2} accumulations could further help guide the development of safe and cost-effective design and operation methods for engineered CO{sub 2} storage sites.

  8. Synthesis and biodistribution of radioiodinated nicotine analogs

    Energy Technology Data Exchange (ETDEWEB)

    Chan, S.M.; Basmadjian, G.P.; Sadek, S.A.; Magarian, R.A.; Grunder, J.R.; Marten, D.F.

    1986-06-01

    Four /sup 125/I-labelled nicotine analogs were synthesized: 3-(methylpropylaminomethyl)-, 3-(diethylaminomethyl)-, 3-(isopropylaminomethyl)-, and 3-(diisopropylaminomethyl)-5-(/sup 125/I)-iodopyridines. 5-Bromonicotinic acid was acylated with thionyl chloride and then reacted with the appropriate primary and secondary amines to give the corresponding amides which were reduced with diborane to the desirable amines. Radioiodination was done by halogen exchange. Biodistribution studies in rats, showed that all four labelled compounds were rapidly taken up by the brain and the adrenal gland. This was followed by rapid washout of the compounds from these organs. The most promising of these compounds, 3-(diisopropylaminomethyl)-5-(/sup 125/I)-iodopyridine, showed a brain-to-blood ratio of 6.0:1 and an adrenal-to-blood ratio of 35.9:1 at 2 minutes post administration. In vitro correlation studies showed that brain uptake of these compounds depends on both protein binding and lipophilicity, whereas adrenal uptake depends only on lipophilicity.

  9. Amino acid analogs for tumor imaging

    Science.gov (United States)

    Goodman, M.M.; Shoup, T.

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

  10. Biosynthesis of sphinganine-analog mycotoxins.

    Science.gov (United States)

    Du, L; Zhu, X; Gerber, R; Huffman, J; Lou, L; Jorgenson, J; Yu, F; Zaleta-Rivera, K; Wang, Q

    2008-06-01

    Sphinganine-analog mycotoxins (SAMT) are polyketide-derived natural products produced by a number of plant pathogenic fungi and are among the most economically important mycotoxins. The toxins are structurally similar to sphinganine, a key intermediate in the biosynthesis of ceramides and sphingolipids, and competitive inhibitors for ceramide synthase. The inhibition of ceramide and sphingolipid biosynthesis is associated with several fatal diseases in domestic animals and esophageal cancer and neural tube defects in humans. SAMT contains a highly reduced, acyclic polyketide carbon backbone, which is assembled by a single module polyketide synthase. The biosynthesis of SAMT involves a unique polyketide chain-releasing mechanism, in which a pyridoxal 5'-phosphate-dependent enzyme catalyzes the termination, offloading and elongation of the polyketide chain. This leads to the introduction of a new carbon-carbon bond and an amino group to the polyketide chain. The mechanism is fundamentally different from the thioesterase/cyclase-catalyzed polyketide chain releasing found in bacterial and other fungal polyketide biosynthesis. Genetic data suggest that the ketosynthase domain of the polyketide synthase and the chain-releasing enzyme are important for controlling the final product structure. In addition, several post-polyketide modifications have to take place before SAMT become mature toxins.

  11. HERE, THERE, AND EVERYWHEREPublic Science Through Analogy

    Science.gov (United States)

    Arcand, Kimberly K.

    2014-06-01

    Here, There, and Everywhere (HTE) is a program that consists of a series of exhibitions, posters, and supporting hands-on activities that utilize analogies in the teaching of science, engineering, and technology to provide multi-generational and family-friendly content in English and Spanish to small community centers, libraries, under-resourced small science centers. The purpose of the program is to connect crosscutting science content (in Earth, atmospheric and planetary sciences and astrophysics) with everyday phenomena. By using different modes of content delivery, from physical exhibits and handouts,to interpretive stations, facilitated activities for educators, and online resources, HTE helps to demonstrate the universality of physical laws and the connection between our everyday world and the universe as a whole to members of the public who may not identify strongly with science. HTE is part of a series of public science projects created and developed by the Education and Public Outreach group at the Chandra X-ray Center. The authors discuss how HTE fits into the lineage of public science outreach that aims to engage the greater public in non-traditional venues for science learning and appreciation, as well as what might be learned about the participants of such projects.

  12. Natural Analog Studies at Pena Blanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    A.M. Simmons

    2005-07-11

    The significance of the Pena Blanca uranium deposits in the State of Chihuahua, Mexico as potential natural analogs for a nuclear waste repository in unsaturated welded tuff was first recognized in the 1980s. In the 1970s, the Pena Blanca region was a major target of uranium exploration and exploitation by the Mexican government. Since then the Nopal I uranium deposit has been studied extensively by researchers in the U.S., Mexico, and Europe. The Nopal I deposit represents an environment similar to that of the proposed high-level radioactive waste repository at Yucca Mountain in many ways. Both are located in semi-arid regions. Both are located in Tertiary rhyolitic tuffs overlying carbonate rocks that have been subjected to basin and range-style tectonic deformation. Both are located in a chemically oxidizing, unsaturated zone 200 m or more above the water table. The alteration of uraninite to secondary minerals at Nopal I may be similar to the alteration of uranium fuel rods in this type of setting. Investigations at Nopal I and in the surrounding Sierra Pena Blanca have included detailed outcrop mapping, hydrologic and isotopic studies of flow and transport, studies of mineral alteration, modeling, and performance assessment.

  13. Nonpeptide somatostatin analogs: recent advances in its application and research

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Along with its wide anatomical distribution, somatostatin (SST) acts on multiple targets via a family of 5 receptors to produce a broad spectrum of biological effects. Therefore, a variety of peptide analogs have been produced and are widely used in clinical treatment. However, because of their flaws in the structure of peptide, the clinical efficacy is limited. In this review, we summarize the structure, pharmacological effects and the potential clinical value of non-peptide SST analogs. We focus on the research and development of non-peptide SST analogs since 1998, and discuss the problems and potential prospects for non-peptide SST analogs. We believe that as more non-peptide somatostatin analogs are successfully developed, the extensive clinical application of SSTs will contribute a great deal to medical science.

  14. Learning Plate Tectonics Using a Pre-Analogy Step

    Science.gov (United States)

    Glesener, G. B.; Sandoval, W. A.

    2011-12-01

    Previous research has shown that children tend to demonstrate lower performance on analogical reasoning tasks at a causal relations level compared to most adults (Gentner & Toupin, 1986). This tendency is an obstacle that geoscience educators must overcome because of the high frequency of analogies used in geoscience pedagogy. In particular, analog models are used to convey complex systems of non-everyday/non-observable events found in nature, such as plate tectonics. Key factors in successful analogical reasoning that have been suggested by researchers include knowledge of the causal relations in the base analog (Brown & Kane, 1988; Gentner, 1988; Gentner & Toupin, 1986), and development of learning strategies and metaconceptual competence(Brown & Kane, 1988). External factors, such as guiding cues and hints have been useful cognitive supports that help students reason through analogical problems (Gick & Holyoak, 1980). Cognitive supports have been seen by researchers to decrease processing demands on retrieval and working memory (Richland, Zur, & Holyoak, 2007). We observed third and fourth graders learning about plate tectonics beginning with a pre-analogy step-a cognitive support activity a student can do before working with an analogy to understand the target. This activity was designed to aid students in developing their understanding of object attributes and relations within an analog model so that more focus can be placed on mapping the corresponding higher-order relations between the base and target. Students learned targeted concepts of plate tectonics, as measured by pre to post gains on items adapted from the Geosciences Concept Inventory. Analyses of classroom interaction showed that students used the object attributes and higher-order relations highlighted in the pre-analogy activity as resources to reason about plate boundaries and plate movement during earthquakes.

  15. NASA HRP Immunology Discipline - Use of Terrestrial Analogs

    Science.gov (United States)

    Crucian, Brian

    2014-01-01

    Due to the cost and operational constraints, as well as technical implementation limitations, it is desirous to perform relevant space physiology investigations first in terrestrial 'space analogs'. This is particularly true for initial investigations, which may then provide appropriate focus for subsequent flight investigations, or for mechanistic investigations that simply cannot be performed during spaceflight. Appropriate analog choice is extremely important. There are a wide variety of terrestrial space analogs, each relevant to a particular physiological discipline (or disciplines) and each with a particular fidelity (or lack thereof) to spaceflight, and each with unique operational constraints. The HRP Immunology Discipline is tasked with managing the HRP Risk concerning clinical risk for Astronaut crews related to spaceflight-associated immune dysregulation. Such dysregulation has been documented to occur during spaceflight, and found to persist for the duration of a 6-month ISS mission. Studies continue to characterize the onorbit phenomenon, but it generally consists of diminished immunocyte function, dysregulated cytokine profiles, and persistent herpesvirus reactivation. Causes are thought to synergistically include microgravity, psychological or physiological stress, radiation, and/or circadian misalignment. An appropriate terrestrial analog for immune dysregulation would replicate as many of these influences as possible. Such analogs may include clinostat or bioreactor cell culture (microgravity), hindlimb suspension (stress, fluid shifts, hypokinesis), or human deployment to remote or extreme environments (isolation, stress, circadian). Also, the laboratory setting may be used as an analog, or to augment analogs, such as sleep deprivation/misalignment or human centrifugation to replicate gravitational stress. As an appropriate example of a NASA Disciplines use of Terrestrial space analogs, this talk will discuss spaceflight associated immune

  16. Differentiation of Keratinocytes Modulates Skin HPA Analog.

    Science.gov (United States)

    Wierzbicka, Justyna M; Żmijewski, Michał A; Antoniewicz, Jakub; Sobjanek, Michal; Slominski, Andrzej T

    2017-01-01

    It is well established, that epidermal keratinocytes express functional equivalent of hypothalamus-pituitary-adrenal axis (HPA) in order to respond to changing environment and maintain internal homeostasis. We are presenting data indicating that differentiation of primary neonatal human keratinocytes (HPEKp), induced by prolonged incubation or calcium is accompanied by significant changes in the expression of the elements of skin analog of HPA (sHPA). Expression of CRF, UCN1-3, POMC, ACTH, CRFR1, CRFR2, MC1R, MC2R, and GR (coded by NR3C1 gene) were observed on gene/protein levels along differentiation of keratinocytes in culture with similar pattern seen by immunohistochemistry on full thickness skin biopsies. Expression of CRF was more pronounced in less differentiated keratinocytes, which corresponded to the detection of CRF immunoreactivity preferentially in the stratum basale. POMC expression was enhanced in more differentiated keratinocytes, which corresponded to detection of ACTH immunoreactivity, predominantly in the stratum spinosum and stratum granulosum. Expression of urocortins was also affected by induction of HPEKp differentiation. Immunohistochemical studies showed high prevalence of CRFR1 in well differentiated keratinocytes, while smaller keratinocytes showed predominantly CRFR2 immunoreactivity. MC2R mRNA levels were elevated from days 4 to 8 of in vitro incubation, while MC2R immunoreactivity was the highest in the upper layers of epidermis. Similar changes in mRNA/protein levels of sHPA elements were observed in HPEKp keratinocytes treated with calcium. Summarizing, preferential expression of CRF and POMC (ACTH) by populations of keratinocytes on different stage of differentiation resembles organization of central HPA axis suggesting their distinct role in physiology and pathology of the epidermis. J. Cell. Physiol. 232: 154-166, 2017. © 2016 Wiley Periodicals, Inc.

  17. De Analogía a Digitalia

    Directory of Open Access Journals (Sweden)

    Dr. Xaime Fandiño Alonso

    2001-01-01

    ía, creatividad y contenidos.ABSTRACTThe transition towards binary-based technology has unleashed dramatic changes that in the last decade have affected the different stages involved in an audiovisual production: from scripting and creating a project, through the various technological procedures of the actual production process to its final distribution.The remains of the analogical era are finally sinking under a seemingly unstoppable wave of constantly evolving new digital environments.The new hardware devices used in this field are mainly prototypes. An ever evolving market, the constant arising of new competitors, newborn joint-ventures and a myriad of related facts force technology providers to keep a pace of constant updating in a mad race of fierce competition.The old system which implied one machine for each process is increasingly becoming a memory of the past. Today new devices are being launched at such a speed that the old technological approach which dealt with mechanical appliances like magnetoscopes, closed platforms and linear recording are already bound for extinction.It’s only natural then that the sacred cows of the industry fear for their position. Big and small are elusive concepts in this new audiovisual frenzy. Its almost daily routine to read about big audiovisual corporations announcing mergers, buy-outs or the acquisition of a stake in new and small creativity and development firms built from scratch by young entrepreneurs out of the blue.The digital era is drawing a heavy curtain that luckily leaves behind an analogical era in which the ownership of the costly means of production was the most important card in the game. The artist could only exercise its art if access to the professional team and technical equipment required for an audiovisual work was granted by its proprietors.Today, digital means new systems with far more productive environments which besides are user-friendly and cost only a small fraction of the old hardware.Right now, with

  18. A quantum analog of Huffman coding

    CERN Document Server

    Braunstein, S L; Gottesman, D; Lo, H K; Braunstein, Samuel L.; Fuchs, Christopher A.; Gottesman, Daniel; Lo, Hoi-Kwong

    1998-01-01

    We analyse a generalization of Huffman coding to the quantum case. In particular, we notice various difficulties in using instantaneous codes for quantum communication. However, for the storage of quantum information, we have succeeded in constructing a Huffman-coding inspired quantum scheme. The number of computational steps in the encoding and decoding processes of N quantum signals can be made to be polynomial in log N by a massively parallel implementation of a quantum gate array. This is to be compared with the N^3 computational steps required in the sequential implementation by Cleve and DiVincenzo of the well-known quantum noiseless block coding scheme by Schumacher. The powers and limitations in using this scheme in communication are also discussed.

  19. A homogenized constrained mixture (and mechanical analog) model for growth and remodeling of soft tissue.

    Science.gov (United States)

    Cyron, C J; Aydin, R C; Humphrey, J D

    2016-12-01

    Most mathematical models of the growth and remodeling of load-bearing soft tissues are based on one of two major approaches: a kinematic theory that specifies an evolution equation for the stress-free configuration of the tissue as a whole or a constrained mixture theory that specifies rates of mass production and removal of individual constituents within stressed configurations. The former is popular because of its conceptual simplicity, but relies largely on heuristic definitions of growth; the latter is based on biologically motivated micromechanical models, but suffers from higher computational costs due to the need to track all past configurations. In this paper, we present a temporally homogenized constrained mixture model that combines advantages of both classical approaches, namely a biologically motivated micromechanical foundation, a simple computational implementation, and low computational cost. As illustrative examples, we show that this approach describes well both cell-mediated remodeling of tissue equivalents in vitro and the growth and remodeling of aneurysms in vivo. We also show that this homogenized constrained mixture model suggests an intimate relationship between models of growth and remodeling and viscoelasticity. That is, important aspects of tissue adaptation can be understood in terms of a simple mechanical analog model, a Maxwell fluid (i.e., spring and dashpot in series) in parallel with a "motor element" that represents cell-mediated mechanoregulation of extracellular matrix. This analogy allows a simple implementation of homogenized constrained mixture models within commercially available simulation codes by exploiting available models of viscoelasticity.

  20. Current-mode analog nonlinear function synthesizer structures

    CERN Document Server

    Popa, Cosmin Radu

    2013-01-01

    This book is dedicated to the analysis and design of analog CMOS nonlinear function synthesizer structures, based on original superior-order approximation functions. A variety of analog function synthesizer structures are discussed, based on accurate approximation functions.  Readers will be enabled to implement numerous circuit functions with applications in analog signal processing, including exponential, Gaussian or hyperbolic functions. Generalizing the methods for obtaining these particular functions, the author analyzes superior-order approximation functions, which represent the core for developing CMOS analog nonlinear function synthesizers.   ·         Describes novel methods for generating a multitude of circuit functions, based on superior-order improved accuracy approximation functions; ·         Presents techniques for analog function synthesizers that can be applied easily to a wide variety of analog signal processing circuits; ·         Enables the design of analog s...

  1. Graph-Based Symbolic Technique and Its Application in the Frequency Response Bound Analysis of Analog Integrated Circuits

    Directory of Open Access Journals (Sweden)

    E. Tlelo-Cuautle

    2014-01-01

    Full Text Available A new graph-based symbolic technique (GBST for deriving exact analytical expressions like the transfer function H(s of an analog integrated circuit (IC, is introduced herein. The derived H(s of a given analog IC is used to compute the frequency response bounds (maximum and minimum associated to the magnitude and phase of H(s, subject to some ranges of process variational parameters, and by performing nonlinear constrained optimization. Our simulations demonstrate the usefulness of the new GBST for deriving the exact symbolic expression for H(s, and the last section highlights the good agreement between the frequency response bounds computed by our variational analysis approach versus traditional Monte Carlo simulations. As a conclusion, performing variational analysis using our proposed GBST for computing the frequency response bounds of analog ICs, shows a gain in computing time of 100x for a differential circuit topology and 50x for a 3-stage amplifier, compared to traditional Monte Carlo simulations.

  2. Formal analogy between the Dirac equation in its Majorana form and the discrete-velocity version of the Boltzmann kinetic equation.

    Science.gov (United States)

    Fillion-Gourdeau, F; Herrmann, H J; Mendoza, M; Palpacelli, S; Succi, S

    2013-10-18

    We point out a formal analogy between the Dirac equation in Majorana form and the discrete-velocity version of the Boltzmann kinetic equation. By a systematic analysis based on the theory of operator splitting, this analogy is shown to turn into a concrete and efficient computational method, providing a unified treatment of relativistic and nonrelativistic quantum mechanics. This might have potentially far-reaching implications for both classical and quantum computing, because it shows that, by splitting time along the three spatial directions, quantum information (Dirac-Majorana wave function) propagates in space-time as a classical statistical process (Boltzmann distribution).

  3. Synthesis and evaluation of diverse analogs of amygdalin as potential peptidomimetics of peptide T.

    Science.gov (United States)

    Araya, Eyleen; Rodriguez, Alex; Rubio, Jaime; Spada, Alessandro; Joglar, Jesus; Llebaria, Amadeu; Lagunas, Carmen; Fernandez, Andres G; Spisani, Susanna; Perez, Juan J

    2005-03-01

    Peptide T (ASTTTNYT) is a promising molecule to prevent the neuropsychometric symptoms of patients suffering AIDS and for the treatment of psoriasis. In order to fully prove its therapeutic benefits, efforts were put forward to design peptidomimetics of the peptide. In this direction, in a recent computational study the natural product amygdalin was identified as a prospective peptidomimetic of the peptide and later proved to exhibit a similar chemotactic profile to the peptide. However, the cyanide moiety of amygdalin provides to the molecule a toxic profile. The present study reports the synthesis of a set of amygdalin analogs lacking the cyanide group with improved chemotactic profiles.

  4. Theoretical spectroscopic characterization at low temperatures of methyl hydroperoxide and three S-analogs

    Energy Technology Data Exchange (ETDEWEB)

    Dalbouha, S., E-mail: samiradalbouha@gmail.com; Senent, M. L., E-mail: senent@iem.cfmac.csic.es [Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia, IEM-C.S.I.C., Serrano 121, Madrid 28006 (Spain); Komiha, N., E-mail: komiha@fsr.ac.ma [LS3ME-Équipe de Chimie Théorique et Modélisation, Faculté des Sciences, Université Mohamed V—Agdal, Rabat (Morocco)

    2015-02-21

    The low temperature spectra of the detectable species methyl hydroperoxide (CH{sub 3}OOH) and three sulfur analogs, the two isomers of methanesulfenic acid (CH{sub 3}SOH and CH{sub 3}OSH) and the methyl hydrogen disulfide (CH{sub 3}SSH), are predicted from highly correlated ab initio methods (CCSD(T) and CCSD(T)-F12). Rotational parameters, anharmonic frequencies, torsional energy barriers, torsional energy levels, and their splittings are provided. Our computed parameters should help for the characterization and the identification of these organic compounds in laboratory and in the interstellar medium.

  5. Theoretical models of pentamidine analogs activity based on their DNA minor groove complexes.

    Science.gov (United States)

    Zołek, Teresa; Maciejewska, Dorota

    2010-05-01

    The B-DNA binding property of pentamidine analogs was analyzed employing molecular dynamic simulations and UV-vis absorption spectroscopy. Their AATT and ATAT sequence preferences were also examined. In theoretical energy computations, we considered two solvation models: the implicit model I, where the solvent is characterized by a dielectric constant and the explicit model E, where water molecules are treated as discrete entities. The binding energy correlates well with the increase of melting temperature of the 5'-d(CGCGAATTCGCG)(2)-3' and 5'-d(CGCGATATCGCG)(2)-3' dodecamers after complexation with ligands (DeltaTm), and deduced models predicted adequately the DNA affinities of the studied diamidines.

  6. Barrel-Clamshell analog in the capillary bridges between two solid spheres

    Science.gov (United States)

    Bird, James; Farmer, Timothy

    2014-11-01

    Sessile drops on a wire are known to adopt one of two topological configurations, referred to as a barrel or a clamshell, depending on the volume and contact angle. Here we report on an analogous topological transition for the capillary bridge between two contacting solid spheres. We characterize the transition by numerically computing the bridge shapes that minimize surface energy for a variety of contact angles and volumes. Finally, we are able to develop an exact solution to the non-axisymmetric bridge shapes by relying on symmetries of the geometry.

  7. UV IRRADIATION OF AROMATIC NITROGEN HETEROCYCLES IN INTERSTELLAR ICE ANALOGS

    Science.gov (United States)

    Elsila, J. E.; Bernstein, M. P.; Sanford, S. A.

    2005-01-01

    Here, we present information on the properties of the ANH quinoline frozen in interstellar water-ice analogs. Quinoline is a two-ring compound structurally analogous to the PAH naphthalene. In this work, binary mixtures of water and quinoline were frozen to create interstellar ice analogs, which were then subjected to ultraviolet photolysis. We will present the infrared spectra of the resulting ices at various temperatures, as well as chromatographic analysis of the residues remaining upon warm-up of these ices to room temperature.

  8. Josephson junction analog and quasiparticle-pair current

    DEFF Research Database (Denmark)

    Bak, Christen Kjeldahl; Pedersen, Niels Falsig

    1973-01-01

    A close analogy exists between a Josephson junction and a phase-locked loop. A new type of electrical analog based on this principle is presented. It is shown that the inclusion in this analog of a low-pass filter gives rise to a current of the same form as the Josephson quasiparticle-pair curren....... A simple picture of the quasiparticle-pair current, which gives the right dependences, is obtained by assuming a junction cutoff frequency to be at the energy gap. ©1973 American Institute of Physics...

  9. Braneworld physics from the analog-gravity perspective

    CERN Document Server

    Barcelo, C; Barcelo, Carlos; Campos, Antonio

    2003-01-01

    We study Randall-Sundrum brane models from the viewpoint of condensed matter/quantum optics. Following the idea of analog gravity we obtain effective metrics in fluid and Bose-Einstein-condensate systems mimicking those in the brane framework. We see that the effect of warp factors in the bulk geometry translates into finite-size of the analog systems. We stress that many open questions in braneworld physics can benefit from the understanding of critical phenomena of surfaces in finite analog systems.

  10. Inhibition of a plant virus infection by analogs of melittin.

    Science.gov (United States)

    Marcos, J F; Beachy, R N; Houghten, R A; Blondelle, S E; Pérez-Payá, E

    1995-01-01

    An approach that enables identification of specific synthetic peptide inhibitors of plant viral infection is reported. Synthetic analogs of melittin that have sequence and structural similarities to an essential domain of tobacco mosaic virus coat protein were found to possess highly specific antiviral activity. This approach involves modification of residues located at positions analogous to those that are critical for virus assembly. The degree of inhibition found correlates well with sequence similarities between the viral capsid protein and the melittin analogs studied as well as with the induced conformational changes that result upon interaction of the peptides and ribonucleic acid. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8618922

  11. High energy density soft X-ray momentum coupling to comet analogs for NEO mitigation

    Science.gov (United States)

    Remo, J. L.; Lawrence, R. J.; Jacobsen, S. B.; Furnish, M. D.

    2016-12-01

    We applied MBBAY high fluence pulsed radiation intensity driven momentum transfer analysis to calculate X-ray momentum coupling coefficients CM=(Pa s)/(J/m2) for two simplified comet analog materials: i) water ice, and ii) 70% water ice and 30% distributed olivine grains. The momentum coupling coefficients (CM) max of 50×10-5 s/m, are about an order of magnitude greater than experimentally determined and computed MBBAY values for meteoritic materials that are analogs for asteroids. From the values for comet analog materials we infer applied energies (via momentum transfer) required to deflect an Earth crossing comet from impacting Earth by a sufficient amount ( 1 cm/s) to avert collision a year in advance. Comet model calculations indicate for CM=5×10-4 s/m the deflection of a 2 km comet with a density 600 kg/m3 by 1 cm/s requires an applied energy on the target surface of 5×1013 J, the equivalent of 12 kT of TNT. Depending on the geometrical configuration of the interaction the explosive yield required could be an order of magnitude higher.

  12. Design and test challenges in Nano-scale analog and mixed CMOS technology

    Directory of Open Access Journals (Sweden)

    Mouna Karmani

    2011-07-01

    Full Text Available The continuous increase of integration densities in Complementary Metal–Oxide–Semiconductor (CMOStechnology has driven the rapid growth of very large scale integrated (VLSI circuit for today's high-techelectronics industries from consumer products to telecommunications and computers. As CMOStechnologies are scaled down into the nanometer range, analog and mixed integrated circuit (IC design andtesting have become a real challenge to ensure the functionality and quality of the product. The first part ofthe paper presents the CMOS technology scaling impact on design and reliability for consumer and criticalapplications. We then propose a discussion on the role and challenges of testing analog and mixed devicesin the nano-scale era. Finally we present the IDDQ testing technique used to detect the most likely defects ofbridging type occurring in analog CMOS circuits during the manufacturing process and creating a resistivepath between VDD supply and the ground.To prove the efficiency of the proposed technique we design a CMOS 90nm operational amplifier (Opamp and a Built in Current Sensor (BICS to validate the technique and correlate it with post layoutsimulation results.

  13. Design and test challenges in Nano-scale analog and mixed CMOS technology

    Directory of Open Access Journals (Sweden)

    Mouna Karmani

    2011-06-01

    Full Text Available The continuous increase of integration densities in Complementary Metal–Oxide–Semiconductor (CMOStechnology has driven the rapid growth of very large scale integrated (VLSI circuit for today's high-tech electronics industries from consumer products to telecommunications and computers. As CMOS technologies are scaled down into the nano meter range, analog and mixed integrated circuit (IC design and testing have become a real challenge to ensure the functionality and quality of the product. The first part of the paper presents the CMOS technology scaling impact on design and reliability for consumer and critical applications. We then propose a discussion on the role and challenges of testing analog and mixed devices in the nano-scale era. Finally we present the IDDQ testing technique used to detect the most likely defects of bridging type occurring in analog CMOS circuits during the manufacturing process and creating a resistive path between VDD supply and the ground.To prove the efficiency of the proposed technique we design a CMOS 90nm operational amplifier (Opamp and a Built in Current Sensor (BICS to validate the technique and correlate it with post layout simulation results.

  14. Airframe Noise Prediction by Acoustic Analogy: Revisited

    Science.gov (United States)

    Farassat, F.; Casper, Jay H.; Tinetti, A.; Dunn, M. H.

    2006-01-01

    The present work follows a recent survey of airframe noise prediction methodologies. In that survey, Lighthill s acoustic analogy was identified as the most prominent analytical basis for current approaches to airframe noise research. Within this approach, a problem is typically modeled with the Ffowcs Williams and Hawkings (FW-H) equation, for which a geometry-independent solution is obtained by means of the use of the free-space Green function (FSGF). Nonetheless, the aeroacoustic literature would suggest some interest in the use of tailored or exact Green s function (EGF) for aerodynamic noise problems involving solid boundaries, in particular, for trailing edge (TE) noise. A study of possible applications of EGF for prediction of broadband noise from turbulent flow over an airfoil surface and the TE is, therefore, the primary topic of the present work. Typically, the applications of EGF in the literature have been limited to TE noise prediction at low Mach numbers assuming that the normal derivative of the pressure vanishes on the airfoil surface. To extend the application of EGF to higher Mach numbers, the uniqueness of the solution of the wave equation when either the Dirichlet or the Neumann boundary condition (BC) is specified on a deformable surface in motion. The solution of Lighthill s equation with either the Dirichlet or the Neumann BC is given for such a surface using EGFs. These solutions involve both surface and volume integrals just like the solution of FW-H equation using FSGF. Insight drawn from this analysis is evoked to discuss the potential application of EGF to broadband noise prediction. It appears that the use of a EGF offers distinct advantages for predicting TE noise of an airfoil when the normal pressure gradient vanishes on the airfoil surface. It is argued that such an approach may also apply to an airfoil in motion. However, for the prediction of broadband noise not directly associated with a trailing edge, the use of EGF does not

  15. Remote computer monitors corrosion protection system

    Energy Technology Data Exchange (ETDEWEB)

    Kendrick, A.

    Effective corrosion protection with electrochemical methods requires some method of routine monitoring that provides reliable data that is free of human error. A test installation of a remote computer control monitoring system for electrochemical corrosion protection is described. The unit can handle up to six channel inputs. Each channel comprises 3 analog signals and 1 digital. The operation of the system is discussed.

  16. Directional coupling for quantum computing and communication.

    Science.gov (United States)

    Nikolopoulos, Georgios M

    2008-11-14

    We introduce the concept of directional coupling, i.e., the selective transfer of a state between adjacent quantum wires, in the context of quantum computing and communication. Our analysis rests upon a mathematical analogy between a dual-channel directional coupler and a composite spin system.

  17. An electrostatic analog for generating cascade grids

    Science.gov (United States)

    Adamczyk, J. J.

    1980-01-01

    Accurate and efficient numerical simulation of flows through turbomachinery blade rows depends on the topology of the computational grids. These grids must reflect the periodic nature of turbomachinery blade row geometries and conform to the blade shapes. Three types of grids can be generated that meet these minimal requirements: through-flow grids, O-type grids, and C-type grids. A procedure which can be used to generate all three types of grids is presented. The resulting grids are orthogonal and can be stretched to capture the essential physics of the flow. A discussion is also presented detailing the extension of the generation procedure to three dimensional geometries.

  18. Mathematical reasoning analogies, metaphors, and images

    CERN Document Server

    English, Lyn D

    2013-01-01

    How we reason with mathematical ideas continues to be a fascinating and challenging topic of research--particularly with the rapid and diverse developments in the field of cognitive science that have taken place in recent years. Because it draws on multiple disciplines, including psychology, philosophy, computer science, linguistics, and anthropology, cognitive science provides rich scope for addressing issues that are at the core of mathematical learning. Drawing upon the interdisciplinary nature of cognitive science, this book presents a broadened perspective on mathematics and mat

  19. Computer Music

    Science.gov (United States)

    Cook, Perry R.

    This chapter covers algorithms, technologies, computer languages, and systems for computer music. Computer music involves the application of computers and other digital/electronic technologies to music composition, performance, theory, history, and the study of perception. The field combines digital signal processing, computational algorithms, computer languages, hardware and software systems, acoustics, psychoacoustics (low-level perception of sounds from the raw acoustic signal), and music cognition (higher-level perception of musical style, form, emotion, etc.).

  20. A Novel cooked extruded lentils analog: physical and chemical properties.

    Science.gov (United States)

    Abu-Ghoush, Mahmoud; Alavi, Sajid; Al-Shathri, Abdulaziz

    2015-07-01

    Developing an extruded lentil analog is our aim. Lentil analog with six formulations were produced using a pilot-scale single (SS) and twin screw (TS) extruders. Texture analysis of lentil analogs prepared for consumption revealed that the products formulated with 60:40 and 70:30 soy: wheat ratios exhibited a significantly higher hardness, adhesiveness and lower springiness as compared to all other treatments. Differential Scanning Calorimeter (DSC) results indicated that all starches in dry blend are completely 100 % gelatinized by extrusion for all treatments at 100 °C. The maximum peak of viscosity for TS was formed after 5.58 min. from the run at 89.9 °C for the best treatment. However, this lentil analog product can provide a high quality lentil which can be used as a substitute for regular lentils.

  1. Reference-Free CMOS Pipeline Analog-to-Digital Converters

    CERN Document Server

    Figueiredo, Michael; Evans, Guiomar

    2013-01-01

    This book shows that digitally assisted analog-to-digital converters are not the only way to cope with poor analog performance caused by technology scaling. It describes various analog design techniques that enhance the area and power efficiency without employing any type of digital calibration circuitry. These techniques consist of self-biasing for PVT enhancement, inverter-based design for improved speed/power ratio, gain-of-two obtained by voltage sum instead of charge redistribution, and current-mode reference shifting instead of voltage reference shifting. Together, these techniques allow enhancing the area and power efficiency of the main building blocks of a multiplying digital-to-analog converter (MDAC) based stage, namely, the flash quantizer, the amplifier, and the switched capacitor network of the MDAC. Complementing the theoretical analyses of the various techniques, a power efficient operational transconductance amplifier is implemented and experimentally characterized. Furthermore, a medium-low ...

  2. Digitoxin and its analogs as novel cancer therapeutics

    Directory of Open Access Journals (Sweden)

    Elbaz Hosam A

    2012-04-01

    Full Text Available Abstract A growing body of evidence indicates that digitoxin cardiac glycoside is a promising anticancer agent when used at therapeutic concentrations. Digitoxin has a prolonged half-life and a well-established clinical profile. New scientific avenues have shown that manipulating the chemical structure of the saccharide moiety of digitoxin leads to synthetic analogs with increased cytotoxic activity. However, the anticancer mechanism of digitoxin or synthetic analogs is still subject to study while concerns about digitoxin's cardiotoxicity preclude its clinical application in cancer therapeutics. This review focuses on digitoxin and its analogs, and their cytotoxicity against cancer cells. Moreover, a new perspective on the pharmacological aspects of digitoxin and its analogs is provided to emphasize new research directions for developing potent chemotherapeutic drugs.

  3. Analog and digital signal analysis from basics to applications

    CERN Document Server

    Cohen Tenoudji, Frédéric

    2016-01-01

    This book provides comprehensive, graduate-level treatment of analog and digital signal analysis suitable for course use and self-guided learning. This expert text guides the reader from the basics of signal theory through a range of application tools for use in acoustic analysis, geophysics, and data compression. Each concept is introduced and explained step by step, and the necessary mathematical formulae are integrated in an accessible and intuitive way. The first part of the book explores how analog systems and signals form the basics of signal analysis. This section covers Fourier series and integral transforms of analog signals, Laplace and Hilbert transforms, the main analog filter classes, and signal modulations. Part II covers digital signals, demonstrating their key advantages. It presents z and Fourier transforms, digital filtering, inverse filters, deconvolution, and parametric modeling for deterministic signals. Wavelet decomposition and reconstruction of non-stationary signals are also discussed...

  4. Interaction of algorithm and implementation for analog VLSI stereo vision

    Science.gov (United States)

    Hakkarainen, J. M.; Little, James J.; Lee, Hae-Seung; Wyatt, John L., Jr.

    1991-07-01

    Design of a high-speed stereo vision system in analog VLSI technology is reported. The goal is to determine how the advantages of analog VLSI--small area, high speed, and low power-- can be exploited, and how the effects of its principal disadvantages--limited accuracy, inflexibility, and lack of storage capacity--can be minimized. Three stereo algorithms are considered, and a simulation study is presented to examine details of the interaction between algorithm and analog VLSI implementation. The Marr-Poggio-Drumheller algorithm is shown to be best suited for analog VLSI implementation. A CCD/CMOS stereo system implementation is proposed, capable of operation at 6000 image frame pairs per second for 48 X 48 images, and faster than frame rate operation on 256 X 256 binocular image pairs.

  5. A Uniform Approach to Analogies, Synonyms, Antonyms, and Associations

    CERN Document Server

    Turney, Peter D

    2008-01-01

    Recognizing analogies, synonyms, antonyms, and associations appear to be four distinct tasks, requiring distinct NLP algorithms. In the past, the four tasks have been treated independently, using a wide variety of algorithms. These four semantic classes, however, are a tiny sample of the full range of semantic phenomena, and we cannot afford to create ad hoc algorithms for each semantic phenomenon; we need to seek a unified approach. We propose to subsume a broad range of phenomena under analogies. To limit the scope of this paper, we restrict our attention to the subsumption of synonyms, antonyms, and associations. We introduce a supervised corpus-based machine learning algorithm for classifying analogous word pairs, and we show that it can solve multiple-choice SAT analogy questions, TOEFL synonym questions, ESL synonym-antonym questions, and similar-associated-both questions from cognitive psychology.

  6. Wideband Analog Data System (WADS), system design document

    Science.gov (United States)

    Brose, J. F.

    1979-01-01

    The Wideband Analog System (WADS) which performs post flight structural dynamic analysis of wideband FM data recorded during orbital flight tests is defined. Screening, reporting, and plotting steady state and transient wave analysis data are provided by WADS.

  7. A gravito-electromagnetic analogy based on tidal tensors

    CERN Document Server

    Costa, L F; Herdeiro, Carlos A. R.

    2006-01-01

    We propose a new approach to a physical analogy between General Relativity and Electromagnetism, based on comparing tidal tensors of both theories. Using this approach we write a covariant form for the gravitational analogues of the Maxwell equations, from which the regime of validity of the analogy becomes manifest. Two explicit realisations of the analogy are given. The first one matches linearised gravitational tidal tensors to exact electromagnetic tidal tensors in Minkwoski spacetime. The second one matches exact magnetic gravitational tidal tensors for ultra-stationary metrics to exact magnetic tidal tensors of electromagnetism in curved spaces. We then establish a new proof for a class of tensor identities that define invariants of the type $\\vec{E}^2-\\vec{B}^2$ and $\\vec{E}\\cdot\\vec{B}$, and we exhibit the invariants built from tidal tensors in both gravity and electromagnetism. We contrast our approach with the two gravito-electromagnetic analogies commonly found in the literature, which are reviewed...

  8. Energy Harvesting Using an Analog Circuit under Multimodal Vibration

    Directory of Open Access Journals (Sweden)

    Shigeru Shimose

    2013-01-01

    Full Text Available The efficiency of harvesting energy from a vibrating structure using a piezoelectric transducer and a simple analog circuit is investigated experimentally. This analog circuit was originally invented for a synchronized switch damping on inductor (SSDI technique, which enhances the damping of mechanical vibration. In this study, the circuit is used to implement a synchronized switch harvesting on inductor (SSHI technique. A multiple degree of freedom (MDOF structure is excited by single sinusoidal forces at its resonant frequencies and by random forces. The piezoelectric transducer converts this mechanical energy into electrical energy which is harvested using a standard rectifier bridge circuit with and without our analog circuit. Experimental results show that our analog circuit makes it possible to harvest twice as much energy under both single sinusoidal and random vibration excitations.

  9. Project Birdseye Aerial Photograph Collection: Digital and Analog Materials

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection consists of both analog and digital aerial photographs from Arctic areas in and around Baffin Bay, the Labrador Sea, the Arctic Ocean, the Beaufort...

  10. 22nd Workshop on Advances in Analog Circuit Design

    CERN Document Server

    Makinwa, Kofi; Harpe, Pieter

    2014-01-01

    This book is based on the 18 tutorials presented during the 22nd workshop on Advances in Analog Circuit Design.  Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, including frequency reference, power management for systems-on-chip, and smart wireless interfaces.  This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.    ·         Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; ·         Presents material in a tutorial-based format; ·         Includes coverage of frequency reference, power management for systems-on-chip, and smart wireless interfaces.

  11. BERAS ANALOG SEBAGAI PANGAN FUNGSIONAL DENGAN INDEKS GLIKEMIK RENDAH

    Directory of Open Access Journals (Sweden)

    Santi Noviasari

    2016-04-01

    Full Text Available ABSTRACTThe objective of this research was to produce rice analogue as functional food with low glycemic index. The rice was made from white corn and sorghum with additional soybean flour. The physicochemical properties of rice analogue being analysed were resistant starch content, total phenolic content, dietary fiber, color (L*, +a, +b values and whiteness (oHue. Rice analogue was potentially used as functional food indicated by high level of resistant starch 2.59%-3.31%, total phenolic content 0.18-0.25 mg GAE/g sample and dietary fiber 5.35%-6.14%. Rice analogue from white corn with and without soybean flour was further tested for glycemic index. Rice analogue from white corn has 69 GI value, while rice analogue from white corn with 10% soybean flour addition has 50 GI value.Keywords: functional food, glycemic index, rice analogueABSTRAKTujuan penelitian ini adalah untuk mendapatkan beras analog yang berpotensi sebagai pangan fungsional dan bernilai indeks glikemik rendah. Beras analog dibuat dari bahan baku jagung putih dan sorgum dengan penambahan tepung kedelai. Sifat fisiko kimia beras analog yang dianalisis adalah pati resisten, total fenol, serat pangan, warna (nilai L*, +a, +b dan derajat putih (oHue. Beras analog berpotensi sebagai pangan fungsional, yang ditunjukkan dengan tingginya kadar pati resisten yaitu sebanyak 2,59%-3,31%, total fenol sekitar 0,18-0,25 mg GAE/g sampel dan serat pangan antara 5,35%-6,14%. Beras analog berbahan baku jagung putih dengan dan tanpa penambahan kedelai dipilih untuk uji indeks glikemik. Beras analog dari jagung putih memiliki nilai IG 69 sedangkan beras analog dari jagung putih dengan penambahan tepung kedelai 10% memiliki nilai IG 50.Kata kunci: beras analog, indeks glikemik, pangan fungsional

  12. SEARCHING FOR THE SIGNATURES OF TERRESTRIAL PLANETS IN SOLAR ANALOGS

    OpenAIRE

    Hernandez, J. I. Gonzalez; Israelian, G.; Santos,N.C.; Sousa, S.; Delgado-Mena, E.; Neves, V.; Udry, S.

    2010-01-01

    We present a fully differential chemical abundance analysis using very high-resolution (R >~ 85,000) and very high signal-to-noise (S/N~800 on average) HARPS and UVES spectra of 7 solar twins and 95 solar analogs, 24 are planet hosts and 71 are stars without detected planets. The whole sample of solar analogs provide very accurate Galactic chemical evolution trends in the metalliciy range -0.3

  13. Chemical and physical effects in the bulk of cometary analogs

    Science.gov (United States)

    Roessler, K.; Benit, Jean; Sauer, M.

    1992-01-01

    KOSI comet simulation experiments were designed as a macroscopic tester for the studies of physicochemical problems inherent to comet bodies. The analog samples consist of H2O and CO2 ice, organic admixtures, mineral dust, and carbon. Two of the fundamental changes the analogs undergo when submitted to 'insolation' by artificial sunlight, i.e., the diffusion of frozen gases and subsequent crust formation and the natural isotopic fractionation, are reported.

  14. Microwave assisted synthesis of 6-Substituted aminopurine analogs in water

    OpenAIRE

    Qu, Guirong; Han,Suhui; Zhang,Zhiguang; Geng,Mingwei; Xue, Feng

    2006-01-01

    Microwave assisted amination of 6-chloropurine derivatives with various amines in water resulted in a "green chemistry" protocol for the preparation of 6-substituted aminopurine analogs in very good yields. Using a simply modified microwave oven with the refluxing apparatus, the amination of the 6-chloro in the purine structure occurred smoothly. 19 known and 16 unknown 6-substituted aminopurine analogs were prepared through nucleophilic aromatic substitution with simple filtration or column ...

  15. Error Models of the Analog to Digital Converters

    OpenAIRE

    Michaeli Linus; Šaliga Ján

    2014-01-01

    Error models of the Analog to Digital Converters describe metrological properties of the signal conversion from analog to digital domain in a concise form using few dominant error parameters. Knowledge of the error models allows the end user to provide fast testing in the crucial points of the full input signal range and to use identified error models for post correction in the digital domain. The imperfections of the internal ADC structure determine the error characteristics represented by t...

  16. Analog readout modules for the ZEUS microvertex detector

    CERN Document Server

    Fusayasu, T

    1999-01-01

    Analog readout modules have been developed for a silicon microvertex detector of the electron-proton collision experiment ZEUS. Analog signals kept in the front end are read out and digitized by ADCs and processed afterwards to reduce the data volume while keeping the signal information. We have developed prototype modules with 10-bit 10 MHz ADCs and digital processors built in Field Programmable Gate Arrays. Their performance was investigated.

  17. Analog Filter Design Rules for Multilevel Polybinary Signaling Generation

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Cavallero, Francisco javier Vaquero; Tafur Monroy, Idelfonso

    2014-01-01

    Polybinary signaling has gained attention lately due to its generation simplicity and reduced spectral usage. This paper presents a study on the requirements for analog filters for the generation of multilevel polybinary signals with three to nine levels.......Polybinary signaling has gained attention lately due to its generation simplicity and reduced spectral usage. This paper presents a study on the requirements for analog filters for the generation of multilevel polybinary signals with three to nine levels....

  18. Fluorinated Analogs of Malachite Green: Synthesis and Toxicity

    Directory of Open Access Journals (Sweden)

    Bahram Parvin

    2008-04-01

    Full Text Available A series of fluorinated analogs of malachite green (MG have been synthesizedand their toxicity to Saccharomyces cerevisiae and a human ovarian epithelial cell lineexamined. The toxicity profiles were found to be different for these two species. Twoanalogs, one with 2,4-difluoro substitution and the other with 2-fluoro substitution seem tobe the most promising analogs because they showed the lowest toxicity to the human cells.

  19. Structure- and isoform-specific glucuronidation of six curcumin analogs.

    Science.gov (United States)

    Lu, Danyi; Liu, Hui; Ye, Wencai; Wang, Ying; Wu, Baojian

    2017-04-01

    1. In the present study, we aimed to characterize the glucuronidation of six curcumin analogs (i.e. RAO-3, RAO-8, RAO-9, RAO-18, RAO-19, and RAO-23) derived from galangal using human liver microsomes (HLM) and twelve expressed UGT enzymes. 2. Formation of glucuronide was confirmed using high-resolution mass spectrometry. Single glucuronide metabolite was generated from each of six curcumin analogs. The fragmentation patterns were analyzed and were found to differ significantly between alcoholic and phenolic glucuronides. 3. All six curcumin analogs except one (RAO-23) underwent significant glucuronidation in HLM and expressed UGT enzymes. In general, the methoxy group (close to the phenolic hydroxyl group) enhanced the glucuronidation liability of the curcumin analogs. 4. UGT1A9 and UGT2B7 were primarily responsible for the glucuronidation of two alcoholic analogs (RAO-3 and RAO-18). By contrast, UGT1A9 and four UGT2Bs (UGT2B4, 2B7, 2B15 and 2B17) played important roles in conjugating three phenolic analogs (RAO-8, RAO-9, and RAO-19). Interestingly, the conjugated double bonds system (in the aliphatic chain) was crucial to the substrate selectivity of gastrointestinal UGTs (i.e. UGT1A7, 1A8 and 1A10). 5. In conclusion, glucuronidation of six curcumin analogs from galangal were structure- and isoform-specific. The knowledge should be useful in identifying a curcumin analog with improved metabolic property.

  20. Direct (under) Sampling vs. Analog Downconversion for BPM Electroncs

    CERN Document Server

    Wendt, M

    2014-01-01

    Digital signal processing by means of undersampling the analog signal has become a popular method for acquiring beam position monitor signals. This presentation discusses the technique and its principle limitations, presents today’s technical limits (e.g. in terms of performance of available ADCs), and provides an outlook for the future. It will also try to compare the technique with more tradition analog downmixing and signal processing methods

  1. Cartographic distortions make dielectric spacetime analog models imperfect mimickers

    Science.gov (United States)

    Fathi, Mohsen; Thompson, Robert T.

    2016-06-01

    It is commonly assumed that if the optical metric of a dielectric medium is identical to the metric of a vacuum space-time then light propagation through the dielectric mimics light propagation in the vacuum. However, just as the curved surface of the Earth cannot be mapped into a flat plane without distortion of some surface features, so too is it impossible to project the behavior of light from the vacuum into a dielectric analog residing in Minkowski space-time without introducing distortions. We study the covariance properties of dielectric analog space-times and the kinematics of a congruence of light in the analog, and show how certain features can be faithfully emulated in the analog depending on the choice of projection, but that not all features can be simultaneously emulated without distortion. These findings indicate conceptual weaknesses in the idea of using analog space-times as a basis for transformation optics, and we show that a certain formulation of transformation optics closely related to analog space-times resolves these issues.

  2. Glycolaldehyde in Perseus young solar analogs

    Science.gov (United States)

    De Simone, M.; Codella, C.; Testi, L.; Belloche, A.; Maury, A. J.; Anderl, S.; André, Ph.; Maret, S.; Podio, L.

    2017-03-01

    Context. The earliest evolutionary stages of low-mass protostars are characterised by the so-called hot-corino stage, when the newly born star heats the surrounding material and enrich the gas chemically. Studying this evolutionary phase of solar protostars may help understand the evolution of prebiotic complex molecules in the development of planetary systems. Aims: In this paper we focus on the occurrence of glycolaldehyde (HCOCH2OH) in young solar analogs by performing the first homogeneous and unbiased study of this molecule in the Class 0 protostars of the nearby Perseus star forming region. Methods: We obtained sub-arcsec angular resolution maps at 1.3 mm and 1.4 mm of glycolaldehyde emission lines using the IRAM Plateau de Bure (PdB) interferometer in the framework of the CALYPSO IRAM large program. Results: Glycolaldehyde has been detected towards 3 Class 0 and 1 Class I protostars out of the 13 continuum sources targeted in Perseus: NGC 1333-IRAS2A1, NGC 1333-IRAS4A2, NGC 1333-IRAS4B1, and SVS13-A. The NGC 1333 star forming region looks particularly glycolaldehyde rich, with a rate of occurrence up to 60%. The glycolaldehyde spatial distribution overlaps with the continuum one, tracing the inner 100 au around the protostar. A large number of lines (up to 18), with upper-level energies Eu from 37 K up to 375 K has been detected. We derived column densities ≥1015 cm-2 and rotational temperatures Trot between 115 K and 236 K, imaging for the first time hot-corinos around NGC 1333-IRAS4B1 and SVS13-A. Conclusions: In multiple systems glycolaldehyde emission is detected only in one component. The case of the SVS13-A+B and IRAS4-A1+A2 systems support that the detection of glycolaldehyde (at least in the present Perseus sample) indicates older protostars (i.e. SVS13-A and IRAS4-A2), evolved enough to develop the hot-corino region (i.e. 100 K in the inner 100 au). However, only two systems do not allow us to firmly conclude whether the primary factor leading to

  3. Analog Modeling of Continental Lithosphere Subduction

    Science.gov (United States)

    Willingshofer, E.; Sokoutis, D.; Luth, S.; Beekman, F.; Cloetingh, S.

    2012-12-01

    Lithospheric-scale analog modeling sheds light on the consequences of decoupling within the continental lithosphere and along plate interfaces during continental collision. The model results provide valuable information in terms of strain localization, deformation of the subducting slab and the evolution and architecture of the overlying mountain belt and its topography. A weak layer has been implemented in three-layer models to simulate decoupling along the plate interface and at different levels of the lithosphere (brittle-ductile transition, entire lower crust, crust-mantle boundary). Additionally, varying the strength of the mantle lithosphere of both the upper as well as the lower plate regulated the degree of plate coupling. Plate boundaries were orthogonal to the convergence direction. All models emphasize that strong decoupling at the plate interface is a pre-requisite for the subduction of continental lithosphere. In addition, deformation of the subducting slab was found to be sensitive to the strength contrast between the subduction zone and the mantle lithosphere of the downgoing as well as the upper plate. As such, a low strength contrast between the plate interface and the lower plate leads to deformation of the subducting slab by thickening and the development of a shallow slab. Conversely, when the strength contrast is high, deep slabs evolve which undergo relatively less deformation. Furthermore, the level of decoupling in the downgoing plate governs how much continental crust is subducted together with the mantle lithosphere. Shallow decoupling, at the brittle-ductile transition, results in subduction of the lower crust whereas small amounts of lower crust are subducted when decoupling occurs at the level of the Moho. Weak plate coupling and a weak lower crust of the lower plate steer the evolution of mountain belts such that deformation propagates outward, in the direction of the incoming plate, by successive imbrication of upper crustal thrust

  4. The three and a half layers of dynamics : analog, digital, semi-digital, analog

    CERN Document Server

    Singh, T P

    2011-01-01

    Quantum theory is extremely successful in explaining most physical phenomena, and is not contradicted by any experiment. Yet, the theory has many puzzling features : the occurrence of probabilities, the unclear distinction between the microscopic and the macroscopic, the unexplained absence of superpositions in positions of macroscopic objects, the dependence of the theory on an external classical time, and the experimentally verified but peculiar `influence' outside the light-cone in EPR experiments. These puzzles point towards a conflict between quantum theory and our present understanding of spacetime structure, and suggest the existence of a deeper theory. In this essay we make the case that in the underlying theory the matter and spacetime degrees of freedom are non-commuting matrices, and yet the dynamics is analog. A digital quantum-theory like dynamics for matter as well as spacetime emerges in the statistical thermodynamic approximation to this deeper theory. When most of the matter clumps into macro...

  5. Model, analysis, and evaluation of the effects of analog VLSI arithmetic on linear subspace-based image recognition.

    Science.gov (United States)

    Carvajal, Gonzalo; Figueroa, Miguel

    2014-07-01

    Typical image recognition systems operate in two stages: feature extraction to reduce the dimensionality of the input space, and classification based on the extracted features. Analog Very Large Scale Integration (VLSI) is an attractive technology to achieve compact and low-power implementations of these computationally intensive tasks for portable embedded devices. However, device mismatch limits the resolution of the circuits fabricated with this technology. Traditional layout techniques to reduce the mismatch aim to increase the resolution at the transistor level, without considering the intended application. Relating mismatch parameters to specific effects in the application level would allow designers to apply focalized mismatch compensation techniques according to predefined performance/cost tradeoffs. This paper models, analyzes, and evaluates the effects of mismatched analog arithmetic in both feature extraction and classification circuits. For the feature extraction, we propose analog adaptive linear combiners with on-chip learning for both Least Mean Square (LMS) and Generalized Hebbian Algorithm (GHA). Using mathematical abstractions of analog circuits, we identify mismatch parameters that are naturally compensated during the learning process, and propose cost-effective guidelines to reduce the effect of the rest. For the classification, we derive analog models for the circuits necessary to implement Nearest Neighbor (NN) approach and Radial Basis Function (RBF) networks, and use them to emulate analog classifiers with standard databases of face and hand-writing digits. Formal analysis and experiments show how we can exploit adaptive structures and properties of the input space to compensate the effects of device mismatch at the application level, thus reducing the design overhead of traditional layout techniques. Results are also directly extensible to multiple application domains using linear subspace methods.

  6. Grid Computing

    Indian Academy of Sciences (India)

    2016-05-01

    A computing grid interconnects resources such as high performancecomputers, scientific databases, and computercontrolledscientific instruments of cooperating organizationseach of which is autonomous. It precedes and is quitedifferent from cloud computing, which provides computingresources by vendors to customers on demand. In this article,we describe the grid computing model and enumerate themajor differences between grid and cloud computing.

  7. Computer Virus

    Institute of Scientific and Technical Information of China (English)

    高振桥

    2002-01-01

    If you work with a computer,it is certain that you can not avoid dealing, with at least one computer virus.But how much do you know about it? Well,actually,a computer virus is not a biological' one as causes illnesses to people.It is a kind of computer program

  8. Computational composites

    DEFF Research Database (Denmark)

    Vallgårda, Anna K. A.; Redström, Johan

    2007-01-01

    Computational composite is introduced as a new type of composite material. Arguing that this is not just a metaphorical maneuver, we provide an analysis of computational technology as material in design, which shows how computers share important characteristics with other materials used in design...... and architecture. We argue that the notion of computational composites provides a precise understanding of the computer as material, and of how computations need to be combined with other materials to come to expression as material. Besides working as an analysis of computers from a designer’s point of view......, the notion of computational composites may also provide a link for computer science and human-computer interaction to an increasingly rapid development and use of new materials in design and architecture....

  9. An Analog Front End for Recording Neuronal Activity in Freely Behaving Small Animals

    Institute of Scientific and Technical Information of China (English)

    WANG Min; ZHANG Xiao; ZHANG Chun-feng; CAO Mao-yong; LI Cai-fang; KONG Hui-min; QIN Feng-ju; YAN Yu-qin

    2007-01-01

    Abstract.Extracting characteristic brain signals and simultaneous recording animals behaving could help us to understand the complex behavior of neuronal ensembles. Here,a system was established to record local field potentials (LFP) and extracellular signal or multiple-unit discharge and behavior synchronously by utilizing electrophysiology and integrated circuit technique. It comprised microelectrodes and micro-driver assembly, analog front end ( AFE), while a computer ( Pentium Ⅲ ) was used as the platform for the graphic user interface, which was developed using the LabVIEW programming language. It was designed as a part of ongoing research to develop a portable wireless neural signal recording system. We believe that this information will be useful for the research of brain-computer interface.

  10. An analog integrated signal processing circuit for on-chip diffusion-based gas analysis

    Science.gov (United States)

    Sadeghi, Hesam; Ghafarinia, Vahid

    2013-07-01

    In diffusion-based gas analysis, the transient of gas diffusion process is recorded by a generic gas sensor to serve as a fingerprint for qualitative and quantitative analysis of gaseous samples. Following the acquisition of these specific signals, any standalone gas analyzer requires a pattern recognition system for pattern classification. The classic digital pattern recognition methods require computing hardware of adequate computational throughput. In this paper, we have followed a straightforward mathematical procedure to relate the signals to their associated target gases. We have shown that the procedure can be implemented by a set of analog functions. Based on the results, we have designed an analog integrated circuit, in 0.18 µm standard CMOS process, for processing the diffusion-based transient signals. The main circuit components are a low-pass filter, the differentiator, the feature extractor and an artificial neural network. The output of the circuit is a 2-bit binary code that specifies the target gas. The circuit successfully classified four alcoholic vapors by processing the experimentally obtained response patterns. The proposed signal processing circuit, the semiconductor gas sensor and the diffusion channel can all be implemented on a single substrate to fabricate an integrated micro gas analyzer.

  11. Computational chemistry

    OpenAIRE

    2000-01-01

    Computational chemistry has come of age. With significant strides in computer hardware and software over the last few decades, computational chemistry has achieved full partnership with theory and experiment as a tool for understanding and predicting the behavior of a broad range of chemical, physical, and biological phenomena. The Nobel Prize award to John Pople and Walter Kohn in 1998 highlighted the importance of these advances in computational chemistry. With massively parallel computers ...

  12. A Framework for Heterotic Computing

    Directory of Open Access Journals (Sweden)

    Susan Stepney

    2012-10-01

    Full Text Available Computational devices combining two or more different parts, one controlling the operation of the other, for example, derive their power from the interaction, in addition to the capabilities of the parts. Non-classical computation has tended to consider only single computational models: neural, analog, quantum, chemical, biological, neglecting to account for the contribution from the experimental controls. In this position paper, we propose a framework suitable for analysing combined computational models, from abstract theory to practical programming tools. Focusing on the simplest example of one system controlled by another through a sequence of operations in which only one system is active at a time, the output from one system becomes the input to the other for the next step, and vice versa. We outline the categorical machinery required for handling diverse computational systems in such combinations, with their interactions explicitly accounted for. Drawing on prior work in refinement and retrenchment, we suggest an appropriate framework for developing programming tools from the categorical framework. We place this work in the context of two contrasting concepts of "efficiency": theoretical comparisons to determine the relative computational power do not always reflect the practical comparison of real resources for a finite-sized computational task, especially when the inputs include (approximations of real numbers. Finally we outline the limitations of our simple model, and identify some of the extensions that will be required to treat more complex interacting computational systems.

  13. Duality Computing in Quantum Computers

    Institute of Scientific and Technical Information of China (English)

    LONG Gui-Lu; LIU Yang

    2008-01-01

    In this letter, we propose a duality computing mode, which resembles particle-wave duality property when a quantum system such as a quantum computer passes through a double-slit. In this mode, computing operations are not necessarily unitary. The duality mode provides a natural link between classical computing and quantum computing. In addition, the duality mode provides a new tool for quantum algorithm design.

  14. An Optimized Analogy-Based Project Effort Estimation

    Directory of Open Access Journals (Sweden)

    Mohammad Azzeh

    2014-05-01

    Full Text Available despite the predictive performance of Analogy-Based Estimation (ABE in generating better effort estimates, there is no consensus on: (1 how to predetermine the appropriate number of analogies, (2 which adjustment technique produces better estimates. Yet, there is no prior works attempted to optimize both number of analogies and feature distance weights for each test project. Perhaps rather than using fixed number, it is better to optimize this value for each project individually and then adjust the retrieved analogies by optimizing and approximating complex relationships between features and reflects that approximation on the final estimate. The Artificial Bees Algorithm is utilized to find, for each test project, the appropriate number of closest projects and features distance weights that is used to adjust those analogies’ efforts. The proposed technique has been applied and validated to 8 publically datasets from PROMISE repository. Results obtained show that: (1 the predictive performance of ABE has noticeably been improved, (2 the number of analogies was remarkably variable for each test project. While there are many techniques to adjust ABE, Using optimization algorithm provides two solutions in one technique and appeared useful for datasets with complex structure.

  15. Bioisosteric phentolamine analogs as potent alpha-adrenergic antagonists.

    Science.gov (United States)

    Hong, Seoung-Soo; Bavadekar, Supriya A; Lee, Sang-Il; Patil, Popat N; Lalchandani, S G; Feller, Dennis R; Miller, Duane D

    2005-11-01

    The synthesis and biological evaluation of a new series of bioisosteric phentolamine analogs are described. Replacement of the carbon next to the imidazoline ring of phentolamine with a nitrogen atom provides compounds (2, 3) that are about 1.6 times and 4.1 times more potent functionally than phentolamine on rat alpha1-adrenergic receptors, respectively. In receptor binding assays, the affinities of phentolamine and its bioisosteric analogs were determined on the human embryonic kidney (HEK) and Chinese Hamster ovary (CHO) cell lines expressing the human alpha1- and alpha2-AR subtypes, respectively. Analogs 2 and 3, both, displayed higher binding affinities at the alpha2- versus the alpha1-ARs, affinities being the least at the alpha1B-AR. Binding affinities of the methoxy ether analog 2 were greater than those of the phenolic analog 3 at all six alpha-AR subtypes. One of the nitrogen atoms in the imidazoline ring of phentolamine was replaced with an oxygen atom to give compounds 4 and 5, resulting in a 2-substituted oxazoline ring. The low functional antagonist activity on rat aorta, and binding potencies of these two compounds on human alpha1A- and alpha2A-AR subtypes indicate that a basic functional group is important for optimum binding to the alpha1- and alpha2A-adrenergic receptors.

  16. Long-duration bed rest as an analog to microgravity.

    Science.gov (United States)

    Hargens, Alan R; Vico, Laurence

    2016-04-15

    Long-duration bed rest is widely employed to simulate the effects of microgravity on various physiological systems, especially for studies of bone, muscle, and the cardiovascular system. This microgravity analog is also extensively used to develop and test countermeasures to microgravity-altered adaptations to Earth gravity. Initial investigations of bone loss used horizontal bed rest with the view that this model represented the closest approximation to inactivity and minimization of hydrostatic effects, but all Earth-based analogs must contend with the constant force of gravity by adjustment of the G vector. Later concerns about the lack of similarity between headward fluid shifts in space and those with horizontal bed rest encouraged the use of 6 degree head-down tilt (HDT) bed rest as pioneered by Russian investigators. Headward fluid shifts in space may redistribute bone from the legs to the head. At present, HDT bed rest with normal volunteers is the most common analog for microgravity simulation and to test countermeasures for bone loss, muscle and cardiac atrophy, orthostatic intolerance, and reduced muscle strength/exercise capacity. Also, current physiologic countermeasures are focused on long-duration missions such as Mars, so in this review we emphasize HDT bed rest studies with durations of 30 days and longer. However, recent results suggest that the HDT bed rest analog is less representative as an analog for other important physiological problems of long-duration space flight such as fluid shifts, spinal dysfunction and radiation hazards.

  17. Antimicrobial and cell-penetrating properties of penetratin analogs

    DEFF Research Database (Denmark)

    Bahnsen, Jesper Søborg; Franzyk, Henrik; Sandberg-Schaal, Anne;

    2013-01-01

    Cell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) show great potential as drug delivery vectors and new antibiotic drug entities, respectively. The current study deals with the properties of a variety of peptide analogs derived from the well-known CPP penetratin as well as octaar......Cell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) show great potential as drug delivery vectors and new antibiotic drug entities, respectively. The current study deals with the properties of a variety of peptide analogs derived from the well-known CPP penetratin as well...... as octaarginine and different Tat sequences. The effects of peptide length, guanidinium content, and sequence of non-cationic residues were assessed in mammalian and bacterial cells. The arginine (Arg) content in the penetratin analogs was found to influence eukaryotic cell uptake efficiency, antimicrobial...... activity towards both Gram-positive and Gram-negative bacteria as well as eukaryotic cell viability. All examined analogs retained the ability to cross eukaryotic membranes giving rise to a distribution within the vacuolar apparatus. Interestingly, a series of shuffled analogs of penetratin...

  18. New insights into the synergism of nucleoside analogs with radiotherapy.

    Science.gov (United States)

    Lee, Michael W; Parker, William B; Xu, Bo

    2013-09-26

    Nucleoside analogs have been frequently used in combination with radiotherapy in the clinical setting, as it has long been understood that inhibition of DNA repair pathways is an important means by which many nucleoside analogs synergize. Recent advances in our understanding of the structure and function of deoxycytidine kinase (dCK), a critical enzyme required for the anti-tumor activity for many nucleoside analogs, have clarified the mechanistic role this kinase plays in chemo- and radio-sensitization. A heretofore unrecognized role of dCK in the DNA damage response and cell cycle machinery has helped explain the synergistic effect of these agents with radiotherapy. Since most currently employed nucleoside analogs are primarily activated by dCK, these findings lend fresh impetus to efforts focused on profiling and modulating dCK expression and activity in tumors. In this review we will briefly review the pharmacology and biochemistry of the major nucleoside analogs in clinical use that are activated by dCK. This will be followed by discussions of recent advances in our understanding of dCK activation via post-translational modifications in response to radiation and current strategies aimed at enhancing this activity in cancer cells.

  19. VUV spectroscopy of carbon dust analogs: contribution to interstellar extinction

    Science.gov (United States)

    Gavilan, L.; Alata, I.; Le, K. C.; Pino, T.; Giuliani, A.; Dartois, E.

    2016-02-01

    Context. A full spectral characterization of carbonaceous dust analogs is necessary to understand their potential as carriers of observed astronomical spectral signatures such as the ubiquitous UV bump at 217.5 nm and the far-ultraviolet (FUV) rise common to interstellar extinction curves. Aims: Our goal is to study the spectral properties of carbonaceous dust analogs from the FUV to the mid-infrared (MIR) domain. We seek in particular to understand the spectra of these materials in the FUV range, for which laboratory studies are scarce. Methods: We produced analogs to carbonaceous interstellar dust encountered in various phases of the interstellar medium: amorphous hydrogenated carbons (a-C:H), for carbonaceous dust observed in the diffuse interstellar medium, and soot particles, for the polyaromatic component. Analogs to a-C:H dust were produced using a radio-frequency plasma reactor at low pressures, and soot nanoparticles films were produced in an ethylene (C2H4) flame. We measured transmission spectra of these thin films (thickness Kronig inversion. We used these constants for comparison to existing interstellar extinction curves. Conclusions: We extend the spectral measurements of these types of carbonaceous analogs into the VUV and link the spectral features in this range to the 3.4 μm band. We suggest that these two materials might contribute to different classes of interstellar extinction curves.

  20. Novel trypanocidal analogs of 5'-(methylthio)-adenosine.

    Science.gov (United States)

    Sufrin, Janice R; Spiess, Arthur J; Marasco, Canio J; Rattendi, Donna; Bacchi, Cyrus J

    2008-01-01

    The purine nucleoside 5'-deoxy-5'-(hydroxyethylthio)-adenosine (HETA) is an analog of the polyamine pathway metabolite 5'-deoxy-5'-(methylthio)-adenosine (MTA). HETA is a lead structure for the ongoing development of selectively targeted trypanocidal agents. Thirteen novel HETA analogs were synthesized and examined for their in vitro trypanocidal activities against bloodstream forms of Trypanosoma brucei brucei LAB 110 EATRO and at least one drug-resistant Trypanosoma brucei rhodesiense clinical isolate. New compounds were also assessed in a cell-free assay for their activities as substrates of trypanosome MTA phosphorylase. The most potent analog in this group was 5'-deoxy-5'-(hydroxyethylthio)-tubercidin, whose in vitro cytotoxicity (50% inhibitory concentration [IC50], 10 nM) is 45 times greater than that of HETA (IC50, 450 nM) against pentamidine-resistant clinical isolate KETRI 269. Structure-activity analyses indicate that the enzymatic cleavage of HETA analogs by trypanosome MTA phosphorylase is not an absolute requirement for trypanocidal activity. This suggests that additional biochemical mechanisms are associated with the trypanocidal effects of HETA and its analogs.

  1. Computational manufacturing

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper presents a general framework for computational manufacturing. The methodology of computational manufacturing aims at integrating computational geometry, machining principle, sensor information fusion, optimization, computational intelligence and virtual prototyping to solve problems of the modeling, reasoning, control, planning and scheduling of manufacturing processes and systems. There are three typical problems in computational manufacturing, i.e., scheduling (time-domain), geometric reasoning (space-domain) and decision- making (interaction between time-domain and space-domain). Some theoretical fundamentals of computational manufacturing are also discussed.

  2. Structural analyses of covalent enzyme-substrate analog complexes reveal strengths and limitations of de novo enzyme design.

    Science.gov (United States)

    Wang, Ling; Althoff, Eric A; Bolduc, Jill; Jiang, Lin; Moody, James; Lassila, Jonathan K; Giger, Lars; Hilvert, Donald; Stoddard, Barry; Baker, David

    2012-01-20

    We report the cocrystal structures of a computationally designed and experimentally optimized retro-aldol enzyme with covalently bound substrate analogs. The structure with a covalently bound mechanism-based inhibitor is similar to, but not identical with, the design model, with an RMSD of 1.4 Å over active-site residues and equivalent substrate atoms. As in the design model, the binding pocket orients the substrate through hydrophobic interactions with the naphthyl moiety such that the oxygen atoms analogous to the carbinolamine and β-hydroxyl oxygens are positioned near a network of bound waters. However, there are differences between the design model and the structure: the orientation of the naphthyl group and the conformation of the catalytic lysine are slightly different; the bound water network appears to be more extensive; and the bound substrate analog exhibits more conformational heterogeneity than typical native enzyme-inhibitor complexes. Alanine scanning of the active-site residues shows that both the catalytic lysine and the residues around the binding pocket for the substrate naphthyl group make critical contributions to catalysis. Mutating the set of water-coordinating residues also significantly reduces catalytic activity. The crystal structure of the enzyme with a smaller substrate analog that lacks naphthyl ring shows the catalytic lysine to be more flexible than in the naphthyl-substrate complex; increased preorganization of the active site would likely improve catalysis. The covalently bound complex structures and mutagenesis data highlight the strengths and weaknesses of the de novo enzyme design strategy.

  3. Using Analogies in Teaching Physics: A Study on Latvian Teachers' Views and Experience

    Science.gov (United States)

    Jonane, Lolita

    2015-01-01

    The role of analogies as tools for teaching difficult science concepts has been widely discussed in science education. The application of analogies in the context of sustainable education involves richer potential. The purposeful use of appropriate analogies can facilitate analogical thinking and transfer skills, as well as develop abilities which…

  4. Effects of Multimedia and Schema Induced Analogical Reasoning on Science Learning

    Science.gov (United States)

    Zheng, R. Z.; Yang, W.; Garcia, D.; McCadden, E. P.

    2008-01-01

    The present study investigates the effects of multimedia and schema induced analogical reasoning on science learning. It involves 89 fourth grade elementary students in the north-east of the United States. Participants are randomly assigned into four conditions: (a) multimedia with analogy; (b) multimedia without analogy; (c) analogy without…

  5. The Discourse on Printed and Electronic Books: Analogies, Oppositions, and Perspectives

    Science.gov (United States)

    Velagic, Zoran

    2014-01-01

    Introduction: The point of departure for this paper is the twofold analogy (analogy of content, analogy of medium) between printed and electronic books, the aim being to draw attention to the usual perception of their capacities and relationships, to provide a rather detailed analysis of the outcome and sustainability of such analogies and…

  6. Comparison of analog and digital transceiver systems for MR imaging.

    Science.gov (United States)

    Hashimoto, Seitaro; Kose, Katsumi; Haishi, Tomoyuki

    2014-01-01

    We critically evaluated analog and digital transceivers for magnetic resonance (MR) imaging systems under identical experimental conditions to identify and compare their advantages and disadvantages. MR imaging experiments were performed using a 4.74-tesla vertical-bore superconducting magnet and a high sensitivity gradient coil probe. We acquired 3-dimensional spin echo images of a kumquat with and without using a gain-stepping scan technique to extend the dynamic range of the receiver systems. The acquired MR images clearly demonstrated nearly identical image quality for both transceiver systems, but DC and ghosting artifacts were obtained for the analog transceiver system. We therefore concluded that digital transceivers have several advantages over the analog transceivers.

  7. Hydraulic Analogy for Isentropic Flow Through a Nozzle

    Directory of Open Access Journals (Sweden)

    J. S. Rao

    1983-04-01

    Full Text Available Modelling aspects of isentropic compressible gas flow using hydraulic analogy are discussed. Subsonic and supersonic flows through a typical nozzle are simulated as free surface incompressible water flow in an equivalent 2-D model on a water table. The results are first compared for the well known classical analogy in order to estimate experimental errors. Correction factors for pressure and temperature, to account for non-ideal compressible gas flow are presented and the results obtained on the water table are modified and compared with gas dynamic solution. Within the experimental errors, it is shown that the hydraulic analogy can be used as an effective tool for the study of two dimensional isentropic flows of gases.

  8. Practice Utilization of Algorithms for Analog Filter Group Delay Optimization

    Directory of Open Access Journals (Sweden)

    K. Hajek

    2007-04-01

    Full Text Available This contribution deals with an application of three different algorithms which optimize a group delay of analog filters. One of them is a part of the professional circuit simulator Micro Cap 7 and the others two original algorithms are developed in the MATLAB environment. An all-pass network is used to optimize the group delay of an arbitrary analog filter. Introduced algorithms look for an optimal order and optimal coefficients of an all-pass network transfer function. Theoretical foundations are introduced and all algorithms are tested using the optimization of testing analog filter. The optimization is always run three times because the second, third and fourth-order all-pass network is used. An equalization of the original group delay is a main objective of these optimizations. All outputs of all algorithms are critically evaluated and also described.

  9. Analog Circuit Design Optimization Based on Evolutionary Algorithms

    Directory of Open Access Journals (Sweden)

    Mansour Barari

    2014-01-01

    Full Text Available This paper investigates an evolutionary-based designing system for automated sizing of analog integrated circuits (ICs. Two evolutionary algorithms, genetic algorithm and PSO (Parswal particle swarm optimization algorithm, are proposed to design analog ICs with practical user-defined specifications. On the basis of the combination of HSPICE and MATLAB, the system links circuit performances, evaluated through specific electrical simulation, to the optimization system in the MATLAB environment, for the selected topology. The system has been tested by typical and hard-to-design cases, such as complex analog blocks with stringent design requirements. The results show that the design specifications are closely met. Comparisons with available methods like genetic algorithms show that the proposed algorithm offers important advantages in terms of optimization quality and robustness. Moreover, the algorithm is shown to be efficient.

  10. Integrating Problem Solvers from Analogous Markets in New Product Ideation

    DEFF Research Database (Denmark)

    Franke, Nikolaus; Poetz, Marion; Schreier, Martin

    2014-01-01

    Who provides better inputs to new product ideation tasks, problem solvers with expertise in the area for which new products are to be developed or problem solvers from “analogous” markets that are distant but share an analogous problem or need? Conventional wisdom appears to suggest that target...... that including problem solvers from analogous markets versus the target market accounts for almost two-thirds of the well-known effect of involving lead users instead of average problem solvers. This effect is further amplified when the analogous distance between the markets increases, i.e., when searching...... market expertise is indispensable, which is why most managers searching for new ideas tend to stay within their own market context even when they do search outside their firms' boundaries. However, in a unique symmetric experiment that isolates the effect of market origin, we find evidence...

  11. The synthesis of spermine analogs of the shark aminosterol squalamine.

    Science.gov (United States)

    Shu, Youheng; Jones, Stephen R; Kinney, William A; Selinsky, Barry S

    2002-03-01

    Aminosterols isolated from the dogfish shark Squalus acanthias are promising therapeutic agents in the treatment of infection and cancer. One of these, MSI-1436, has been shown to possess antimicrobial activity slightly better than squalamine. In this study, a series of analogs of MSI-1436 have been synthesized from stigmasterol. The 7 alpha-hydroxy substituent of MSI-1436 was either omitted or the stereochemistry modified to the 7 beta position. Also, analogs of MSI-1436 with 24-sulfate, 24-amino, and 24-hydroxy substituents were synthesized in order to assess the importance of the side chain functional group on antimicrobial activity. All of the analogs possess significant antimicrobial activity, suggesting that substitution at C7 and C24 of the aminosterols plays a minor role in their antimicrobial potency.

  12. Application of Op-amp Fixators in Analog Circuits

    Directory of Open Access Journals (Sweden)

    R. Rohith Krishnan

    2016-10-01

    Full Text Available Nullor elements have applications not only in analog behaviour modeling but also in analog circuit design and analysis. Fixator- orator pair, the emerging tool in analog design is a combination of a nullor and sources. A method for the realization of fixator- orator pair is discussed in this paper. Application of fixator-norator pair into a circuit makes it possible to perform the AC and DC designs in a linear like way. Fixator fixes a critical biasing spec at the design, whereas the pairing norator finds the value of power conducting components or DC sources that meets the design. A scaling amplifier design, an active load design and a CMOS differential amplifier design are provided as examples to demonstrate the procedure and the methodology.

  13. Ethnographic analogy, the comparative method, and archaeological special pleading.

    Science.gov (United States)

    Currie, Adrian

    2016-02-01

    Ethnographic analogy, the use of comparative data from anthropology to inform reconstructions of past human societies, has a troubled history. Archaeologists often express concern about, or outright reject, the practice--and sometimes do so in problematically general terms. This is odd, as (or so I argue) the use of comparative data in archaeology is the same pattern of reasoning as the 'comparative method' in biology, which is a well-developed and robust set of inferences which play a central role in discovering the biological past. In pointing out this continuity, I argue that there is no 'special pleading' on the part of archaeologists in this regard: biologists must overcome analogous epistemic difficulties in their use of comparative data. I then go on to emphasize the local, empirically tractable ways in which particular ethnographic analogies may be licensed.

  14. A hybrid digital-analog long pulse integrator

    Science.gov (United States)

    Strait, E. J.; Broesch, J. D.; Snider, R. T.; Walker, M. L.

    1997-01-01

    A digital-analog integrator has been developed for use with inductive magnetic sensors in long-pulse tokamaks. Continuous compensation of input offsets is accomplished by alternating analog-to-digital convertor samples from the sensor and a dummy load, while a RC network provides passive integration between samples. Typically a sampling rate of 10 kHz is used. In operational tests on the DIII-D tokamak, digital and analog integration of tokamak data show good agreement. The output drift error during a 1200 s integration interval corresponds to a few percent of the anticipated signal for poloidal field probes in International Thermonuclear Experimental Reactor, and bench tests suggest that the error can be reduced further.

  15. Diagnosis Method for Analog Circuit Hard fault and Soft Fault

    Directory of Open Access Journals (Sweden)

    Baoru Han

    2013-09-01

    Full Text Available Because the traditional BP neural network slow convergence speed, easily falling in local minimum and the learning process will appear oscillation phenomena. This paper introduces a tolerance analog circuit hard fault and soft fault diagnosis method based on adaptive learning rate and the additional momentum algorithm BP neural network. Firstly, tolerance analog circuit is simulated by OrCAD / Pspice circuit simulation software, accurately extracts fault waveform data by matlab program automatically. Secondly, using the adaptive learning rate and momentum BP algorithm to train neural network, and then applies it to analog circuit hard fault and soft fault diagnosis. With shorter training time, high precision and global convergence effectively reduces the misjudgment, missing, it can improve the accuracy of fault diagnosis and fast.  

  16. Analogical thinking in ecology: looking beyond disciplinary boundaries.

    Science.gov (United States)

    Colyvan, Mark; Ginzburg, Lev R

    2010-06-01

    We consider several ways in which a good understanding of modern techniques and principles in physics can elucidate ecology, and we focus on analogical reasoning between these two branches of science. Analogical reasoning requires an understanding of both sciences and an appreciation of the similarities and points of contact between the two. In the current ecological literature on the relationship between ecology and physics, there has been some misunderstanding about the nature of modern physics and its methods. Physics is seen as being much cleaner and tidier than ecology. When compared to this idealized, fictional version of physics, ecology looks very different, and the prospect of ecology and physics learning from one another is questionable. We argue that physics, once properly understood, is more like ecology than ecologists have thus far appreciated. Physicists and ecologists can and do learn from each other, and, in this paper, we outline how analogical reasoning can facilitate such exchanges.

  17. Synthesis and biological activity of Wuweizisu C and analogs.

    Science.gov (United States)

    Chang, J B; Wang, Q; Li, Y F

    2009-01-01

    Lignans are widely distributed in nature. The earliest recorded medicinal use of lignans dated back to over 1000 years ago. Lignan-rich plant products were also active ingredients in Chinese and Japanese folk medicines for the treatment of various diseases. The dried root and stem of this plant are listed in the Chinese pharmacopoeia for the treatment of rheumatoid arthritis, gastric, duodenal ulcers and many other diseases. This review highlights synthetic strategies for the Wuweizisu C analogs and the important pharmacological activities as well as therapeutic findings related to the treatment of HBV and other diseases. Notably a significant and ongoing project on Wuweizisu C and its analogs has led to the discovery and development of two potent derivatives alpha-DDB and BICYCLOL which are currently in clinical trials against HBV, especially in lowering elevated SGPT levels. Further design, synthesis, and evaluation of Wuweizisu C analogs are discussed.

  18. Synthetic analogs of anoplin show improved antimicrobial activities

    DEFF Research Database (Denmark)

    Munk, Jens; Uggerhøj, Lars Erik; Poulsen, Tanja Juul;

    2013-01-01

    We present the antimicrobial and hemolytic activities of the decapeptide anoplin and 19 analogs thereof tested against methicillin-resistant Staphylococcus aureus ATCC 33591 (MRSA), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), vancomycin-resistant Enterococcus faecium (ATCC...... 700221) (VRE), and Candida albicans (ATCC 200955). The anoplin analogs contain substitutions in amino acid positions 2, 3, 5, 6, 8, 9, and 10. We use these peptides to study the effect of altering the charge and hydrophobicity of anoplin on activity against red blood cells and microorganisms. We find...... that increasing the charge and/or hydrophobicity improves antimicrobial activity and increases hemolytic activity. For each strain tested, we identify at least six anoplin analogs with an improved therapeutic index compared with anoplin, the only exception being Enterococcus faecium, against which only few...

  19. Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing

    Energy Technology Data Exchange (ETDEWEB)

    Gaudi, B; Bennett, D; Udalski, A; Gould, A; Christie, G; Maoz, D; Dong, S; McCormick, J; Szymanski, M; Tristram, P; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; DePoy, D; Han, C; Kaspi, S; Lee, C; Mallia, F; Natusch, T; Pogge, R; Park, B; Abe, F; Bond, I; Botzler, C; Fukui, A; Hearnshaw, J; Itow, Y; Kamiya, K; Korpela, A; Kilmartin, P; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N; Sako, T; Saito, T; Sato, S; Skuljan, L; Sullivan, D; Sumi, T; Sweatman, W; Yock, P; Albrow, M; Beaulieu, J; Burgdorf, M; Cook, K; Coutures, C; Dominik, M; Dieters, S; Fouque, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B

    2007-11-08

    Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the first detection of a multiple-planet system with microlensing. We identify two planets with masses of {approx} 0.71 and {approx} 0.27 times the mass of Jupiter and orbital separations of {approx} 2.3 and {approx} 4.6 astronomical units orbiting a primary of mass {approx} 0.50 solar masses. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only 6 confirmed microlensing planet detections suggests that solar system analogs may be common.

  20. Glutamine analogs promote cytoophidium assembly in human and Drosophila cells

    Institute of Scientific and Technical Information of China (English)

    Kangni Chen; Jing Zhang; (O)mür Yilmaz Tastan; Zillah Anne Deussen; Mayte Yu-Yin Siswick; Ji-Long Liu

    2011-01-01

    CTP synthase is compartmentalized within a subcellular structure,termed the cytoophidium,in a range of organisms including bacteria,yeast,fruit fly and rat.Here we show that CTP synthase is also compartmentalized into cytoophidia in human cells.Surprisingly,the occurrence of cyloophidia in human cells increases upon treatment with a glutamine analog 6-diazo-5-oxo-L-norleucine (DON),an inhibitor of glutaminedependent enzymes including CTP synthase.Experiments in flies confirmned that DON globally promotes cytoophidium assembly.Clonal analysis via CTP synthase RNA interference in somatic cells indicates that CTP synthase expression level is critical for the formation of cytoophidia.Moreover,DON facilitates cytoophidium assembly even when CTP synthase level is low.A second glutamine analog azaserine also promotes cytoophidum formation.Our data demonstrate that glutamine analogs serve as useful tools in the study of cytoophidia.