Sample records for base analog fret-pair

  1. Comparison of NIR FRET pairs for quantitative transferrin-based assay (United States)

    Sinsuebphon, Nattawut; Bevington, Travis; Zhao, Lingling; Ken, Abe; Barroso, Margarida; Intes, Xavier


    Transferrin (Tfn) is commonly used as a drug delivery carrier for cancer treatment. Tfn cellular internalization can be observed by Förster resonance energy transfer (FRET), which occurs when two fluorophores - donor and acceptor - are a few nanometers apart. Donor fluorescence lifetime can be used to sense and quantify FRET occurrence. In FRET state, the donor is quenched leading to a significant reduction in its lifetime. In this study, donor and acceptor near-infrared (NIR) fluorophore-labeled Tfn were used to quantify cellular internalization in breast cancer cell line (T47D). Based on donor lifetime, quantum yield and spectral data, seven NIR FRET pairs were chosen for this comparison. Performance of the different NIR FRET pairs was evaluated in vitro in multiwell plate settings and by analyzing the relationship between quenched donor fraction and acceptor:donor ratio. Additionally, we performed brightness comparison between each pairs. Several parameters, such as brightness, lifetime, R0 and FRET donor population values are used to identify the most suitable NIR FRET pair for in vivo studies in preclinical settings.

  2. In vivo dynamics of enterovirus protease revealed by fluorescence resonance emission transfer (FRET) based on a novel FRET pair

    International Nuclear Information System (INIS)

    Hsu, Y.-Y.; Liu, Y.-N.; Wang Wenyen; Kao, Fu-Jen; Kung, S.-H.


    An in vivo protease assay suitable for analysis by fluorescence resonance energy transfer (FRET) was developed on the basis of a novel FRET pair. The specifically designed fusion substrate consists of green fluorescent protein 2 (GFP 2 )-peptide-red fluorescent protein 2 (DsRed2), with a cleavage motif for the enterovirus 2A protease (2A pro ) embedded within the peptide region. FRET can be readily visualized in real-time from cells expressing the fusion substrate until a proteolytic cleavage by 2A pro from the input virus. The level of FRET decay is a function of the amount and infection duration of the inoculated virus as measured by a fluorometer assay. The FRET biosensor also responded well to other related enteroviruses but not to a phylogenetically distant virus. Western blot analysis confirmed the physical cleavage of the fusion substrate upon the infections. The study provides proof of principle for applying the FRET technology to diagnostics, screening procedures, and cell biological research

  3. FRET pair printing of fluorescent proteins

    NARCIS (Netherlands)

    Escalante, Maryana; Blum, Christian; Cesa, Yanina; Otto, Cees; Subramaniam, Vinod


    We report for the first time the directed assembly and characterization of FRET pairs on micrometer patterned surfaces. We used visible fluorescent proteins expressing a hexahistidine affinity tag as component molecules for the construction of the FRET constructs, where His(6)-EGFP served as donor

  4. Design and Development of a Two-Color Emissive FRET Pair Based on a Photostable Fluorescent Deoxyuridine Donor Presenting a Mega-Stokes Shift. (United States)

    Barthes, Nicolas P F; Gavvala, Krishna; Bonhomme, Dominique; Dabert-Gay, Anne Sophie; Debayle, Delphine; Mély, Yves; Michel, Benoît Y; Burger, Alain


    We report the synthesis and site-specific incorporation in oligodeoxynucleotides (ODNs) of an emissive deoxyuridine analog electronically conjugated on its C5-position with a 3-methoxychromone moiety acting as a fluorophore. When incorporated in ODNs, this fluorescent deoxyuridine analog exhibits remarkable photostability and good quantum yields. This deoxyuridine analog also displays a mega-Stokes shift, which allows for its use as an efficient donor for FRET-based studies when paired with the yellow emissive indocarbocyanine Cy3 acceptor.

  5. Branched DNA nanostructures efficiently stabilised and monitored by novel pyrene-perylene 2'-α-l-amino-LNA FRET pairs

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Santhosh Kumar, T; Campbell, Meghan A


    Novel pyrene-perylene α-l-LNA FRET pairs described herein effectively detect assembly of 2- and 3-way branched DNA nanostructures prepared by postsynthetic microwave-assisted CuAAC click chemistry. The fluorescent signalling of assembly by internally positioned FRET pairs is achieved with low...

  6. A novel FRET pair for detection of parallel DNA triplexes by the LightCycler

    DEFF Research Database (Denmark)

    Schneider, Uffe V; Severinsen, Jette K; Géci, Imrich


    BACKGROUND: Melting temperature of DNA structures can be determined on the LightCycler using quenching of FAM. This method is very suitable for pH independent melting point (Tm) determination performed at basic or neutral pH, as a high throughput alternative to UV absorbance measurements. At acidic...... pH quenching of FAM is not very suitable, since the fluorescence of FAM is strongly pH dependent and drops with acidic pH.Hoogsteen based parallel triplex helix formation requires protonation of cytosines in the triplex forming strand. Therefore, nucleic acid triplexes show strong pH dependence...... reproducibility. Validation of Tm showed low intra- and inter-assay coefficient of variation; 0.11% and 0.14% for parallel triplex and 0.19% and 0.12% for antiparallel duplex. Measurements of Tm and fluorescence intensity over time and multiple runs showed great time and light stability of the ATTO fluorophores...

  7. Single cell FRET analysis for the identification of optimal FRET-pairs in Bacillus subtilis using a prototype MEM-FLIM system.

    Directory of Open Access Journals (Sweden)

    Ruud G J Detert Oude Weme

    Full Text Available Protein-protein interactions can be studied in vitro, e.g. with bacterial or yeast two-hybrid systems or surface plasmon resonance. In contrast to in vitro techniques, in vivo studies of protein-protein interactions allow examination of spatial and temporal behavior of such interactions in their native environment. One approach to study protein-protein interactions in vivo is via Förster Resonance Energy Transfer (FRET. Here, FRET efficiency of selected FRET-pairs was studied at the single cell level using sensitized emission and Frequency Domain-Fluorescence Lifetime Imaging Microscopy (FD-FLIM. For FRET-FLIM, a prototype Modulated Electron-Multiplied FLIM system was used, which is, to the best of our knowledge, the first account of Frequency Domain FLIM to analyze FRET in single bacterial cells. To perform FRET-FLIM, we first determined and benchmarked the best fluorescent protein-pair for FRET in Bacillus subtilis using a novel BglBrick-compatible integration vector. We show that GFP-tagRFP is an excellent donor-acceptor pair for B. subtilis in vivo FRET studies. As a proof of concept, selected donor and acceptor fluorescent proteins were fused using a linker that contained a tobacco etch virus (TEV-protease recognition sequence. Induction of TEV-protease results in loss of FRET efficiency and increase in fluorescence lifetime. The loss of FRET efficiency after TEV induction can be followed in time in single cells via time-lapse microscopy. This work will facilitate future studies of in vivo dynamics of protein complexes in single B. subtilis cells.

  8. Chromium analogs of iron-based superconductors (United States)

    Edelmann, Martin; Sangiovanni, Giorgio; Capone, Massimo; de'Medici, Luca


    We theoretically investigate the d4 (Cr2 +) compound BaCr2As2 and show that, despite non-negligible differences in the electronic structure, its many-body physics mirrors that of BaFe2As2 , which has instead a d6 (Fe2 +) configuration. This reflects a symmetry of the electron correlation effects around the half-filled d5 Mott insulating state. Dynamical mean-field calculations correctly reproduce the experimental antiferromagnetic phase and, for realistic values of the interactions, they show a moderate mass enhancement of order ˜2 . This value can be insensitive to, or even be lowered by, an increase of the interaction parameters, as a result of a larger magnetic moment. In the paramagnetic phase however, correlation effects are much stronger, and the influence of the half-filled Mott insulator shows up as a crossover from a weakly correlated to an orbitally differentiated "Hund's metal" phase. This mirrors an analogous phenomenon in d6 iron compounds including a strong enhancement of the compressibility in a zone just inside the frontier between the normal and the Hund's metal. The experimental evidence and our theoretical description place BaCr2As2 at interaction strength slightly below the crossover which implies that negative pressures and/or electron doping (e.g., Cr → Mn, Fe or Ba → Sc, Y, La) might strongly enhance the compressibility, thereby possibly inducing high-Tc superconductivity in this nonsuperconducting compound.

  9. Analog Circuit Design Optimization Based on Evolutionary Algorithms

    Directory of Open Access Journals (Sweden)

    Mansour Barari


    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. Analogy between gambling and measurement-based work extraction (United States)

    Vinkler, Dror A.; Permuter, Haim H.; Merhav, Neri


    In information theory, one area of interest is gambling, where mutual information characterizes the maximal gain in wealth growth rate due to knowledge of side information; the betting strategy that achieves this maximum is named the Kelly strategy. In the field of physics, it was recently shown that mutual information can characterize the maximal amount of work that can be extracted from a single heat bath using measurement-based control protocols, i.e. using ‘information engines’. However, to the best of our knowledge, no relation between gambling and information engines has been presented before. In this paper, we briefly review the two concepts and then demonstrate an analogy between gambling, where bits are converted into wealth, and information engines, where bits representing measurements are converted into energy. From this analogy follows an extension of gambling to the continuous-valued case, which is shown to be useful for investments in currency exchange rates or in the stock market using options. Moreover, the analogy enables us to use well-known methods and results from one field to solve problems in the other. We present three such cases: maximum work extraction when the probability distributions governing the system and measurements are unknown, work extraction when some energy is lost in each cycle, e.g. due to friction, and an analysis of systems with memory. In all three cases, the analogy enables us to use known results in order to obtain new ones.





    A review study of the most popular type of Analog to Digital Converters- successive approximations, flash, pipelined and sigma-delta has been performed in this paper. The paper elaborates the fundamental operating principles of these architectures and the sources of error experienced in each of these architectures. Further, design considerations and implications, for each architecture, have been put forth. An application based comparison has also been drawn for these architectures with the he...

  12. Analogical reasoning for reliability analysis based on generic data

    Energy Technology Data Exchange (ETDEWEB)

    Kozin, Igor O


    The paper suggests using the systemic concept 'analogy' for the foundation of an approach to analyze system reliability on the basis of generic data, describing the method of structuring the set that defines analogical models, an approach of transition from the analogical model to a reliability model and a way of obtaining reliability intervals of analogous objects.

  13. Analogical reasoning for reliability analysis based on generic data

    International Nuclear Information System (INIS)

    Kozin, Igor O.


    The paper suggests using the systemic concept 'analogy' for the foundation of an approach to analyze system reliability on the basis of generic data, describing the method of structuring the set that defines analogical models, an approach of transition from the analogical model to a reliability model and a way of obtaining reliability intervals of analogous objects

  14. Computer models of pipeline systems based on electro hydraulic analogy (United States)

    Kolesnikov, S. V.; Kudinov, V. A.; Trubitsyn, K. V.; Tkachev, V. K.; Stefanyuk, E. V.


    This paper describes the results of the development of mathematical and computer models of complex multi-loop branched pipeline networks for various purposes (water-oil-gas pipelines, heating networks, etc.) based on the electro hydraulic analogy of current spread in conductors and fluids in pipelines described by the same equations. Kirchhoff’s laws used in the calculation of electrical networks are applied in the calculations for pipeline systems. To maximize the approximation of the computer model to the real network concerning its resistance to the process of transferring the medium, the method of automatic identification of the model is applied.

  15. Visualizing Uncertainty for Probabilistic Weather Forecasting based on Reforecast Analogs (United States)

    Pelorosso, Leandro; Diehl, Alexandra; Matković, Krešimir; Delrieux, Claudio; Ruiz, Juan; Gröeller, M. Eduard; Bruckner, Stefan


    Numerical weather forecasts are prone to uncertainty coming from inaccuracies in the initial and boundary conditions and lack of precision in numerical models. Ensemble of forecasts partially addresses these problems by considering several runs of the numerical model. Each forecast is generated with different initial and boundary conditions and different model configurations [GR05]. The ensembles can be expressed as probabilistic forecasts, which have proven to be very effective in the decision-making processes [DE06]. The ensemble of forecasts represents only some of the possible future atmospheric states, usually underestimating the degree of uncertainty in the predictions [KAL03, PH06]. Hamill and Whitaker [HW06] introduced the "Reforecast Analog Regression" (RAR) technique to overcome the limitations of ensemble forecasting. This technique produces probabilistic predictions based on the analysis of historical forecasts and observations. Visual analytics provides tools for processing, visualizing, and exploring data to get new insights and discover hidden information patterns in an interactive exchange between the user and the application [KMS08]. In this work, we introduce Albero, a visual analytics solution for probabilistic weather forecasting based on the RAR technique. Albero targets at least two different type of users: "forecasters", who are meteorologists working in operational weather forecasting and "researchers", who work in the construction of numerical prediction models. Albero is an efficient tool for analyzing precipitation forecasts, allowing forecasters to make and communicate quick decisions. Our solution facilitates the analysis of a set of probabilistic forecasts, associated statistical data, observations and uncertainty. A dashboard with small-multiples of probabilistic forecasts allows the forecasters to analyze at a glance the distribution of probabilities as a function of time, space, and magnitude. It provides the user with a more

  16. MaMBA - a functional Moon and Mars Base Analog (United States)

    Heinicke, C.; Foing, B.


    Despite impressive progress in robotic exploration of celestial bodies, robots are believed to never reach the effectiveness and efficiency of a trained human. Consequently, ESA proposes to build an international Moon Village in roughly 15 years and NASA plans for the first manned mission to Mars shortly after. One of the challenges still remaining is the need for a shelter, a habitat which allows human spacefarers to safely live and work on the surface of a celestial body. Although a number of prototype habitats has been built during the last decades and inhabited for various durations (e.g. MDRS, FMARS, HI-SEAS, M.A.R.S.), these habitats are typically equipped for studies on human factors and would not function in an extraterrestrial environment. Project MaMBA (Moon and Mars Base Analog) aims to build the first functional habitat based on the lessons learned from intermediate and long duration missions at the mentioned habitats. The habitat will serve for testing technologies like life support, power systems, and interplanetary communi­cation. Special attention will be given to the develop­ment of the geoscience laboratory module. Crews will live and work inside the habitat to ensure its functionality.

  17. Oxindole based oxadiazole hybrid analogs: Novel α-glucosidase inhibitors. (United States)

    Taha, Muhammad; Imran, Syahrul; Rahim, Fazal; Wadood, Abdul; Khan, Khalid Mohammed


    Inhibition of α-glucosidase is an effective strategy for controlling post-prandial hyperglycemia in diabetic patients. Beside these α-glucosidase inhibitors has been also used as anti-obesity and anti-viral drugs. Keeping in view the greater importance of α-glucosidase inhibitors here in this study we are presenting oxindole based oxadiazoles hybrid analogs (1-20) synthesis, characterized by different spectroscopic techniques including 1 H NMR and EI-MS and their α-glucosidase inhibitory activity. All compounds were found potent inhibitors for the enzyme with IC 50 values ranging between 1.25 ± 0.05 and 268.36 ± 4.22 µM when compared with the standard drug acarbose having IC 50 value 895.09 ± 2.04 µM. Our study identifies novel series of potent α-glucosidase inhibitors and further investigation on this may led to the lead compounds. A structure activity relationship has been established for all compounds. The interactions of the active compounds and enzyme active site were established with the help of molecular docking studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Metabolism, Biochemical Actions, and Chemical Synthesis of Anticancer Nucleosides, Nucleotides, and Base Analogs. (United States)

    Shelton, Jadd; Lu, Xiao; Hollenbaugh, Joseph A; Cho, Jong Hyun; Amblard, Franck; Schinazi, Raymond F


    Nucleoside, nucleotide, and base analogs have been in the clinic for decades to treat both viral pathogens and neoplasms. More than 20% of patients on anticancer chemotherapy have been treated with one or more of these analogs. This review focuses on the chemical synthesis and biology of anticancer nucleoside, nucleotide, and base analogs that are FDA-approved and in clinical development since 2000. We highlight the cellular biology and clinical biology of analogs, drug resistance mechanisms, and compound specificity towards different cancer types. Furthermore, we explore analog syntheses as well as improved and scale-up syntheses. We conclude with a discussion on what might lie ahead for medicinal chemists, biologists, and physicians as they try to improve analog efficacy through prodrug strategies and drug combinations.

  19. Grobner Bases for Nonlinear DAE Systems of Analog Circuits

    Directory of Open Access Journals (Sweden)

    Silke J. Spang


    Full Text Available Systems of differential equations play an important role in modelling and analysis of many complex systems e.g. in electronics and mechanics. The following article is concerned with a symbolic analysis approach for reduction of the differential index of nonlinear differential algebraic equation (DAE systems, which occur in the modelling and simulation of analog circuits.

  20. Analog VLSI-based modeling of the primate oculomotor system. (United States)

    Horiuchi, T K; Koch, C


    One way to understand a neurobiological system is by building a simulacrum that replicates its behavior in real time using similar constraints. Analog very large-scale integrated (VLSI) electronic circuit technology provides such an enabling technology. We here describe a neuromorphic system that is part of a long-term effort to understand the primate oculomotor system. It requires both fast sensory processing and fast motor control to interact with the world. A one-dimensional hardware model of the primate eye has been built that simulates the physical dynamics of the biological system. It is driven by two different analog VLSI chips, one mimicking cortical visual processing for target selection and tracking and another modeling brain stem circuits that drive the eye muscles. Our oculomotor plant demonstrates both smooth pursuit movements, driven by a retinal velocity error signal, and saccadic eye movements, controlled by retinal position error, and can reproduce several behavioral, stimulation, lesion, and adaptation experiments performed on primates.

  1. Demonstrations for scanning probe microscopy based on a macroscopic analogy

    Czech Academy of Sciences Publication Activity Database

    Hajková, Z.; Fejfar, Antonín; Smejkal, P.


    Roč. 90, č. 3 (2013), s. 361-363 ISSN 0021-9584 R&D Projects: GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : high school/introductory chemistry * first-year undergraduate/genera * demonstrations * interdisciplinary/multidisciplinary * analogies/transfer * atomic Subject RIV: AM - Education Impact factor: 1.001, year: 2013

  2. Inviting Argument by Analogy: Analogical-Mapping-Based Comparison Activities as a Scaffold for Small-Group Argumentation (United States)

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


    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…

  3. Bandwidth tunable microwave photonic filter based on digital and analog modulation (United States)

    Zhang, Qi; Zhang, Jie; Li, Qiang; Wang, Yubing; Sun, Xian; Dong, Wei; Zhang, Xindong


    A bandwidth tunable microwave photonic filter based on digital and analog modulation is proposed and experimentally demonstrated. The digital modulation is used to broaden the effective gain spectrum and the analog modulation is to get optical lines. By changing the symbol rate of data pattern, the bandwidth is tunable from 50 MHz to 700 MHz. The interval of optical lines is set according to the bandwidth of gain spectrum which is related to the symbol rate. Several times of bandwidth increase are achieved compared to a single analog modulation and the selectivity of the response is increased by 3.7 dB compared to a single digital modulation.

  4. Synthesis of gamma-aminobutyric acid analogs based on carbohydrate scaffolds. (United States)

    Zhong, Ming; Meng, Xiang-Bao; Li, Zhong-Jun


    Gamma-aminobutyric acid analogs based on sugar scaffolds were prepared in six to nine steps starting from D-glucal and D-galactal. The key step in the synthesis is the Vilsmeier-Haack reaction that affords the corresponding 2-C-formyl glycal on treatment with DMF and POCl(3). Oxidation of the aldehyde and reduction of the 4-azido group provided the corresponding GABA analog. Acylamide and tetrazole analogs were also prepared as the bioisosteres of the carboxylic acid. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  5. Teleseism-based Relative Time Corrections for Modern Analyses of Digitized Analog Seismograms (United States)

    Lee, T. A.; Ishii, M.


    With modern-day instruments and seismic networks timed by GPS systems, synchronization of data streams is all but a forgone conclusion. However, during the analog era, when each station had its own clock, comparing data timing from different stations was a far more daunting prospect. Today, with recently developed methods by which analog data can be digitized, having the ability to accurately reconcile the timings of two separate stations would open decades worth of data to modern analyses. For example, one possible and exciting application would be using noise interferometry with digitized analog data in order to investigate changing structural features (on a volcano for example) over a much longer timescale than was previously possible. With this in mind, we introduce a new approach to sync time between stations based on teleseismic arrivals. P-wave arrivals are identified at stations for pairs of earthquakes from the digital and analog eras that have nearly identical distances, locations, and depths. Assuming accurate timing of the modern data, relative time corrections between a pair of stations can then be inferred for the analog data. This method for time correction depends upon the analog stations having modern equivalents, and both having sufficiently long durations of operation to allow for recording of usable teleseismic events. The Hawaii Volcano Observatory (HVO) network is an especially ideal environment for this, as it not only has a large and well-preserved collection of analog seismograms, but also has a long operating history (1912 - present) with many of the older stations having modern equivalents. As such, the scope of this project is to calculate and apply relative time corrections to analog data from two HVO stations, HILB (1919-present) and UWE (1928-present)(HILB now part of Pacific Tsunami network). Further application of this method could be for investigation of the effects of relative clock-drift, that is, the determining factor for how

  6. A computer aided tolerancing tool based on kinematic analogies

    NARCIS (Netherlands)

    Salomons, O.W.; Jonge poerink, H.J.; van Slooten, F.; van Slooten, F.; van Houten, Frederikus J.A.M.; Kals, H.J.J.


    A computer aided tolerancing tool is presented that assists the designer in functional tolerance specification. The theoretical concepts for subsequent tolerance analysis are also provided. The computer aided tolerancing tool is part of a feature based object oriented (re)-design support system,

  7. Investigation of analog/RF performance of staggered heterojunctions based nanowire tunneling field-effect transistors (United States)

    Chakraborty, Avik; Sarkar, Angsuman


    In this paper, the analog/RF performance of an III-V semiconductor based staggered hetero-tunnel-junction (HETJ) n-type nanowire (NW) tunneling FET (n-TFET) is investigated, for the first time. The device performance figure-of-merits governing the analog/RF performance such as transconductance (gm), transconductance-to-drive current ratio (gm/IDS), output resistance (Rout), intrinsic gain and unity-gain cutoff frequency (fT) have been studied. The analog/RF performance parameters is compared between HETJ NW TFET and a homojunction (HJ) NW n-type TFET of similar dimensions. In addition to enhanced ION and subthreshold swing, a significant improvement in the analog/RF performance parameters obtained by the HETJ n-TFET over HJ counterpart for use in analog/mixed signal System-on-Chip (SoC) applications is reported. Moreover, the analog/RF performance parameters of a III-V based staggered HETJ NW TFET is also compared with a heterojunction (HETJ) NW n-type MOSFET having same material as HETJ n-TFET and equal dimension in order to provide a systematic comparison between HETJ-TFET and HETJ-MOSFET for use in analog/mixed-signal applications. The results reveal that HETJ n-TFET provides higher Rout and hence, a higher intrinsic gain, an improved gm/IDS ratio, and reasonable fT at lower values of gate-overdrive voltage as compared to the HETJ NW n-MOSFET.

  8. Doubling-resolution analog-to-digital conversion based on PIC18F45K80

    Directory of Open Access Journals (Sweden)

    Yueyang Yuan


    Full Text Available Aiming at the analog signal being converted into the digital with a higher precision, a method to improve the analog-to-digital converter (ADC resolution is proposed and described. Based on the microcomputer PIC18F45K80 in which the internal ADC modules are embedded, a circuit is designed for doubling the resolution of ADC. According to the circuit diagram, the mathematical formula for calculating this resolution is derived. The corresponding software and print circuit board assembly is also prepared. With the experiment, a 13 bit ADC is achieved based on the 12 bit ADC module predesigned in the PIC18F45K80.

  9. FDSAC-SPICE: fault diagnosis software for analog circuit based on SPICE simulation (United States)

    Cao, Yiqin; Cen, Zhao-Hui; Wei, Jiao-Long


    This paper presents a novel fault diagnosis software (called FDSAC-SPICE) based on SPICE simulator for analog circuits. Four important techniques in AFDS-SPICE, including visual user-interface(VUI), component modeling and fault modeling (CMFM), fault injection and fault simulation (FIFS), fault dictionary and fault diagnosis (FDFD), greatly increase design-for-test and diagnosis efficiency of analog circuit by building a fault modeling-injection-simulationdiagnosis environment to get prior fault knowledge of target circuit. AFDS-SPICE also generates accurate fault coverage statistics that are tied to the circuit specifications. With employing a dictionary diagnosis method based on node-signalcharacters and regular BPNN algorithm, more accurate and effective diagnosis results are available for analog circuit with tolerance.

  10. Problems and Projects Based Approach For Analog Electronic Circuits' Course

    Directory of Open Access Journals (Sweden)

    Mustapha Rafaf


    Full Text Available New educational methods and approaches are recently introduced and implemented at several North American and European universities using Problems and Projects Based Approach (PPBA. The PPBA employs a teaching technique based mostly on competences/skills rather than only on knowledge. This method has been implemented and proven by several pedagogical instructors and authors at several educational institutions. This approach is used at different disciplines such as medicine, biology, engineering and many others. It has the advantage to improve the student's skills and the knowledge retention rate, and reflects the 21st century industrial/company needs and demands. Before implementing this approach to a course, a good resources preparation and planning is needed upfront by the responsible or instructor of the course to achieve the course and students related objectives. This paper presents the preparation, the generated documentation and the implementation of a pilot project utilizing PPBA education for a second year undergraduate electronic course over a complete semester, and for two different class groups (morning and evening groups. The outcome of this project (achieved goals, observed difficulties and lessons learned is presented based on different tools such as students 'in class' communication and feedback, different course evaluation forms and the professor/instructor feedback. Resources, challenges, difficulties and recommendations are also assessed and presented. The impact, the effect and the results (during and at the end of the academic fall session of the PPBA on students and instructor are discussed, validated, managed and communicated to help other instructor in taking appropriate approach decisions with respect to this new educational approach compared to the classical one.

  11. Synthesis of cytotoxic and antioxidant Schiff's base analogs of aloin. (United States)

    Kumar, S; Matharasi, D Priya; Gopi, Sreeraj; Sivakumar, S; Narasimhan, S


    Aloin (10-glucopyranosyl-1,8-dihydroxy-3-hydroxymethyl-9(10H)-anthracenone), a bioactive compound in Aloe vera, although known to have an anticancer effect, has not been used in current drug research. Optimization of the lead structure could enhance the utility of this compound. Hence, aloin was modified using natural amino acids to produce Schiff's base, a potential pharmacophore, and its corresponding aglycones. The synthetic derivatives exhibited significant enhancement in their efficacy toward antioxidant (DPPH radical scavenging) and cytotoxic activities than those of the parent compound, aloin showing promise for application in cancer treatment.

  12. Property-Based Monitoring of Analog and Mixed-Signal Systems (United States)

    Havlicek, John; Little, Scott; Maler, Oded; Nickovic, Dejan

    In the recent past, there has been a steady growth of the market for consumer embedded devices such as cell phones, GPS and portable multimedia systems. In embedded systems, digital, analog and software components are combined on a single chip, resulting in increasingly complex designs that introduce richer functionality on smaller devices. As a consequence, the potential insertion of errors into a design becomes higher, yielding an increasing need for automated analog and mixed-signal validation tools. In the purely digital setting, formal verification based on properties expressed in industrial specification languages such as PSL and SVA is nowadays successfully integrated in the design flow. On the other hand, the validation of analog and mixed-signal systems still largely depends on simulation-based, ad-hoc methods. In this tutorial, we consider some ingredients of the standard verification methodology that can be successfully exported from digital to analog and mixed-signal setting, in particular property-based monitoring techniques. Property-based monitoring is a lighter approach to the formal verification, where the system is seen as a "black-box" that generates sets of traces, whose correctness is checked against a property, that is its high-level specification. Although incomplete, monitoring is effectively used to catch faults in systems, without guaranteeing their full correctness.

  13. Mixing problem based learning and conventional teaching methods in an analog electronics course

    NARCIS (Netherlands)

    Podges, J M; Kommers, P A M; Winnips, K; van Joolingen, W R


    This study, undertaken at the Walter Sisulu University of Technology (WSU) in South Africa, describes how problem-based learning (PBL) affects the first year 'analog electronics course', when PBL and the lecturing mode is compared. Problems were designed to match real-life situations. Data between

  14. Mixing Problem Based Learning And Conventional Teaching Methods In An Analog Electronics Course

    NARCIS (Netherlands)

    Podges, J.M.; Kommers, Petrus A.M.; Winnips, K.; van Joolingen, Wouter


    This study, undertaken at the Walter Sisulu University of Technology (WSU) in South Africa, describes how problem-based learning (PBL) affects the first year ‘analog electronics course’, when PBL and the lecturing mode is compared. Problems were designed to match real-life situations. Data between

  15. Communication disruption of guava moth (Coscinoptycha improbana) using a pheromone analog based on chain length. (United States)

    Suckling, D M; Dymock, J J; Park, K C; Wakelin, R H; Jamieson, L E


    The guava moth, Coscinoptycha improbana, an Australian species that infests fruit crops in commercial and home orchards, was first detected in New Zealand in 1997. A four-component pheromone blend was identified but is not yet commercially available. Using single sensillum recordings from male antennae, we established that the same olfactory receptor neurons responded to two guava moth sex pheromone components, (Z)-11-octadecen-8-one and (Z)-12-nonadecen-9-one, and to a chain length analog, (Z)-13-eicosen-10-one, the sex pheromone of the related peach fruit moth, Carposina sasakii. We then field tested whether this non-specificity of the olfactory neurons might enable disruption of sexual communication by the commercially available analog, using male catch to synthetic lures in traps in single-tree, nine-tree and 2-ha plots. A disruptive pheromone analog, based on chain length, is reported for the first time. Trap catches for guava moth were disrupted by three polyethylene tubing dispensers releasing the analog in single-tree plots (86% disruption of control catches) and in a plots of nine trees (99% disruption). Where peach fruit moth pheromone dispensers were deployed at a density of 1000/ha in two 2-ha areas, pheromone traps for guava moth were completely disrupted for an extended period (up to 470 days in peri-urban gardens in Mangonui and 422 days in macadamia nut orchards in Kerikeri). In contrast, traps in untreated areas over 100 m away caught 302.8 ± 128.1 moths/trap in Mangonui and 327.5 ± 78.5 moths/ trap in Kerikeri. The longer chain length in the pheromone analog has greater longevity than the natural pheromone due to its lower volatility. Chain length analogs may warrant further investigation for mating disruption in Lepidoptera, and screening using single-sensillum recording is recommended.

  16. The possibilities of searching for new materials based on isocationic analogs of ZnBVI (United States)

    Kirovskaya, I. A.; Mironova, E. V.; Kosarev, B. A.; Yureva, A. V.; Ekkert, R. V.


    Acid-base properties of chalcogenides - analogs of ZnBVI - were investigated in detail by modern techniques. The regularities of their composition-dependent changes were set, these regularities correlating with the dependencies "bulk physicochemical property - composition". The main reason for such correlations was found, facilitating the search for new materials of corresponding sensors. In this case, it was the sensors for basic gases impurities.

  17. Digital to analog resistive switching transition induced by graphene buffer layer in strontium titanate based devices. (United States)

    Wan, Tao; Qu, Bo; Du, Haiwei; Lin, Xi; Lin, Qianru; Wang, Da-Wei; Cazorla, Claudio; Li, Sean; Liu, Sidong; Chu, Dewei


    Resistive switching behaviour can be classified into digital and analog switching based on its abrupt and gradual resistance change characteristics. Realizing the transition from digital to analog switching in the same device is essential for understanding and controlling the performance of the devices with various switching mechanisms. Here, we investigate the resistive switching in a device made with strontium titanate (SrTiO 3 ) nanoparticles using X-ray diffractometry, scanning electron microscopy, Raman spectroscopy, and direct electrical measurements. It is found that the well-known rupture/formation of Ag filaments is responsible for the digital switching in the device with Ag as the top electrode. To modulate the switching performance, we insert a reduced graphene oxide layer between SrTiO 3 and the bottom FTO electrode owing to its good barrier property for the diffusion of Ag ions and high out-of-plane resistance. In this case, resistive switching is changed from digital to analog as determined by the modulation of interfacial resistance under applied voltage. Based on that controllable resistance, potentiation and depression behaviours are implemented as well. This study opens up new ways for the design of multifunctional devices which are promising for memory and neuromorphic computing applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Acoustic analog computing based on a reflective metasurface with decoupled modulation of phase and amplitude (United States)

    Zuo, Shu-Yu; Tian, Ye; Wei, Qi; Cheng, Ying; Liu, Xiao-Jun


    The use of metasurfaces has allowed the provision of a variety of functionalities by ultrathin structures, paving the way toward novel highly compact analog computing devices. Here, we conceptually realize analog computing using an acoustic reflective computational metasurface (RCM) that can independently manipulate the reflection phase and amplitude of an incident acoustic signal. This RCM is composed of coating unit cells and perforated panels, where the first can tune the transmission phase within the full range of 2π and the second can adjust the reflection amplitude in the range of 0-1. We show that this RCM can achieve arbitrary reflection phase and amplitude and can be used to realize a unique linear spatially invariant transfer function. Using the spatial Fourier transform (FT), an acoustic analog computing (AAC) system is proposed based on the RCM together with a focusing lens. Based on numerical simulations, we demonstrate that this AAC system can perform mathematical operations such as spatial differentiation, integration, and convolution on an incident acoustic signal. The proposed system has low complexity and reduced size because the RCM is able to individually adjust the reflection phase and amplitude and because only one block is involved in performing the spatial FT. Our work may offer a practical, efficient, and flexible approach to the design of compact devices for acoustic computing applications, signal processing, equation solving, and acoustic wave manipulations.

  19. Event-Based Computation of Motion Flow on a Neuromorphic Analog Neural Platform

    Directory of Open Access Journals (Sweden)

    Massimiliano eGiulioni


    Full Text Available We demonstrate robust optical flow extraction with an analog neuromorphic multi-chip system. The task is performed by a feed-forward network of analog integrate-and-fire neurons whose inputs are provided by contrast-sensitive photoreceptors. Computation is supported by the precise time of spike emission and follows the basic theoretical principles presented in (Benosman et al. 2014: the extraction of the optical flow is based on time lag in the activation of nearby retinal neurons. The same basic principle is embedded in the architecture proposed by Barlow and Levick in 1965 to explain the spiking activity of the direction-selective ganglion cells in the rabbit's retina. Mimicking those cells our neuromorphic detectors encode the amplitude and the direction of the apparent visual motion in their output spiking pattern. We built a 3x3 test grid of independent detectors, each observing a different portion of the scene, so that our final output is a spike train encoding a 3x3 optical flow vector field. In this work we focus on the architectural aspects, and we demonstrate that a network of mismatched delicate analog elements can reliably extract the optical flow from a simple visual scene.

  20. A language based on analogy to communicate cultural concepts in SETI (United States)

    Musso, Paolo


    The present paper is a synthesis of three presentation given by myself at the Toulouse IAC 2001 ( Analogy as a tool to communicate abstract concepts in SETI), the Bremen IAC 2003 ( From maths to culture: towards an effective message), and the Vancouver IAC 2004 ( Philosophical and religious implications of extraterrestrial intelligent life). Its aim is to find a way to make our cultural concepts understandable to hypothetical extraterrestrials (ETs) in a SETI communication. First of all, I expose the reasons why I think that analogy could be a good tool for this purpose. Then, I try to show that this is possible only in the context of an integrated language, using both abstract symbols and pictures, also sketching two practical examples about some basic concepts of our moral and religious tradition. Further studies are required to determine whether this method could be extended to the higher-level abstract concepts in the other fields of our culture. Finally, I discuss the possible role of mathematics, logic and natural science in the construction of an analogy-based language for interstellar messages with a cultural content and a possible way of managing this matter from a social point of view.

  1. Effective Low-Power Wearable Wireless Surface EMG Sensor Design Based on Analog-Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Mohammadreza Balouchestani


    Full Text Available Surface Electromyography (sEMG is a non-invasive measurement process that does not involve tools and instruments to break the skin or physically enter the body to investigate and evaluate the muscular activities produced by skeletal muscles. The main drawbacks of existing sEMG systems are: (1 they are not able to provide real-time monitoring; (2 they suffer from long processing time and low speed; (3 they are not effective for wireless healthcare systems because they consume huge power. In this work, we present an analog-based Compressed Sensing (CS architecture, which consists of three novel algorithms for design and implementation of wearable wireless sEMG bio-sensor. At the transmitter side, two new algorithms are presented in order to apply the analog-CS theory before Analog to Digital Converter (ADC. At the receiver side, a robust reconstruction algorithm based on a combination of ℓ1-ℓ1-optimization and Block Sparse Bayesian Learning (BSBL framework is presented to reconstruct the original bio-signals from the compressed bio-signals. The proposed architecture allows reducing the sampling rate to 25% of Nyquist Rate (NR. In addition, the proposed architecture reduces the power consumption to 40%, Percentage Residual Difference (PRD to 24%, Root Mean Squared Error (RMSE to 2%, and the computation time from 22 s to 9.01 s, which provide good background for establishing wearable wireless healthcare systems. The proposed architecture achieves robust performance in low Signal-to-Noise Ratio (SNR for the reconstruction process.

  2. Event-Based Computation of Motion Flow on a Neuromorphic Analog Neural Platform (United States)

    Giulioni, Massimiliano; Lagorce, Xavier; Galluppi, Francesco; Benosman, Ryad B.


    Estimating the speed and direction of moving objects is a crucial component of agents behaving in a dynamic world. Biological organisms perform this task by means of the neural connections originating from their retinal ganglion cells. In artificial systems the optic flow is usually extracted by comparing activity of two or more frames captured with a vision sensor. Designing artificial motion flow detectors which are as fast, robust, and efficient as the ones found in biological systems is however a challenging task. Inspired by the architecture proposed by Barlow and Levick in 1965 to explain the spiking activity of the direction-selective ganglion cells in the rabbit's retina, we introduce an architecture for robust optical flow extraction with an analog neuromorphic multi-chip system. The task is performed by a feed-forward network of analog integrate-and-fire neurons whose inputs are provided by contrast-sensitive photoreceptors. Computation is supported by the precise time of spike emission, and the extraction of the optical flow is based on time lag in the activation of nearby retinal neurons. Mimicking ganglion cells our neuromorphic detectors encode the amplitude and the direction of the apparent visual motion in their output spiking pattern. Hereby we describe the architectural aspects, discuss its latency, scalability, and robustness properties and demonstrate that a network of mismatched delicate analog elements can reliably extract the optical flow from a simple visual scene. This work shows how precise time of spike emission used as a computational basis, biological inspiration, and neuromorphic systems can be used together for solving specific tasks. PMID:26909015

  3. Interactive NMR: A Simulation Based Teaching Tool for Fundamentals to Applications with Tangible Analogies (United States)

    Griesse-Nascimento, Sarah; Bridger, Joshua; Brown, Keith; Westervelt, Robert


    Interactive computer simulations increase students' understanding of difficult concepts and their ability to explain complex ideas. We created a module of eight interactive programs and accompanying lesson plans for teaching the fundamental concepts of Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) that we call interactive NMR (iNMR). We begin with an analogy between nuclear spins and metronomes to start to build intuition about the dynamics of spins in a magnetic field. We continue to explain T1, T2, and pulse sequences with the metronome analogy. The final three programs are used to introduce and explain the Magnetic Resonance Switch, a recent diagnostic technique based on NMR. A modern relevant application is useful to generate interest in the topic and confidence in the students' ability to apply their knowledge. The iNMR module was incorporated into a high school AP physics class. In a preliminary evaluation of implementation, students expressed enthusiasm and demonstrated enhanced understanding of the material relative to the previous year. Funded by NSF PHY-0646094 grant.

  4. Is neoclassical microeconomics formally valid? An approach based on an analogy with equilibrium thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Tania; Domingos, Tiago [Environment and Energy Section, DEM, Instituto Superior Tecnico, Avenida Rovisco Pais, 1, 1049-001 Lisboa (Portugal)


    The relation between Thermodynamics and Economics is a paramount issue in Ecological Economics. Two different levels can be distinguished when discussing it: formal and substantive. At the formal level, a mathematical framework is used to describe both thermodynamic and economic systems. At the substantive level, thermodynamic laws are applied to economic processes. In Ecological Economics, there is a widespread claim that neoclassical economics has the same mathematical formulation as classical mechanics and is therefore fundamentally flawed because: (1) utility does not obey a conservation law as energy does; (2) an equilibrium theory cannot be used to study irreversible processes. Here, we show that neoclassical economics is based on a wrong formulation of classical mechanics, being in fact formally analogous to equilibrium thermodynamics. The similarity between both formalisms, namely that they are both cases of constrained optimisation, is easily perceived when thermodynamics is looked upon using the Tisza-Callen axiomatisation. In this paper, we take the formal analogy between equilibrium thermodynamics and economic systems far enough to answer the formal criticisms, proving that the formalism of neoclassical economics has irreversibility embedded in it. However, the formal similarity between equilibrium thermodynamics and neoclassical microeconomics does not mean that economic models are in accordance with mass, energy and entropy balance equations. In fact, neoclassical theory suffers from flaws in the substantive integration with thermodynamic laws as has already been fully demonstrated by valuable work done by ecological economists in this field. (author)

  5. Structural development of p-carborane-based potent non-secosteroidal vitamin D analogs. (United States)

    Fujii, Shinya; Sekine, Ryota; Kano, Atsushi; Masuno, Hiroyuki; Songkram, Chalermkiat; Kawachi, Emiko; Hirano, Tomoya; Tanatani, Aya; Kagechika, Hiroyuki


    Non-secosteroidal vitamin D receptor (VDR) ligands are promising candidates for many clinical applications. We recently developed novel non-secosteroidal VDR agonists based on p-carborane (an icosahedral carbon-containing boron cluster) as a hydrophobic core structure. Here, we report the design, synthesis and biological evaluation of carborane-based vitamin D analogs bearing various substituents at the diol moiety. Among the synthesized compounds, methylene derivative 31 exhibited the most potent vitamin D activity, which was comparable to that of the natural hormone, 1α,25(OH)2D3. This compound is one of the most potent non-secosteroidal VDR agonists reported to date, and is a promising lead for development of novel drug candidates. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. A family of chaotic pure analog coding schemes based on baker's map function (United States)

    Liu, Yang; Li, Jing; Lu, Xuanxuan; Yuen, Chau; Wu, Jun


    This paper considers a family of pure analog coding schemes constructed from dynamic systems which are governed by chaotic functions—baker's map function and its variants. Various decoding methods, including maximum likelihood (ML), minimum mean square error (MMSE), and mixed ML-MMSE decoding algorithms, have been developed for these novel encoding schemes. The proposed mirrored baker's and single-input baker's analog codes perform a balanced protection against the fold error (large distortion) and weak distortion and outperform the classical chaotic analog coding and analog joint source-channel coding schemes in literature. Compared to the conventional digital communication system, where quantization and digital error correction codes are used, the proposed analog coding system has graceful performance evolution, low decoding latency, and no quantization noise. Numerical results show that under the same bandwidth expansion, the proposed analog system outperforms the digital ones over a wide signal-to-noise (SNR) range.

  7. Photonic Beamformer Model Based on Analog Fiber-Optic Links’ Components (United States)

    Volkov, V. A.; Gordeev, D. A.; Ivanov, S. I.; Lavrov, A. P.; Saenko, I. I.


    The model of photonic beamformer for wideband microwave phased array antenna is investigated. The main features of the photonic beamformer model based on true-time-delay technique, DWDM technology and fiber chromatic dispersion are briefly analyzed. The performance characteristics of the key components of photonic beamformer for phased array antenna in the receive mode are examined. The beamformer model composed of the components available on the market of fiber-optic analog communication links is designed and tentatively investigated. Experimental demonstration of the designed model beamforming features includes actual measurement of 5-element microwave linear array antenna far-field patterns in 6-16 GHz frequency range for antenna pattern steering up to 40°. The results of experimental testing show good accordance with the calculation estimates.

  8. Parametric estimation in the wave buoy analogy - an elaborated approach based on energy considerations

    DEFF Research Database (Denmark)

    Montazeri, Najmeh; Nielsen, Ulrik Dam


    An accurate estimation of the ocean wave directional spectrum at the location of an advancing ship is very useful for the ship master to improve operation and safety in a seaway. Research has been conducted to obtain sea state estimates by the Wave Buoy Analogy. The method deals with processing...... the ship’s wave-induced responses based on different statistical inferences including parametric and non-parametric approaches. This paper considers a concept to improve the estimate obtained by the parametric method for sea state estimation. The idea is illustrated by an analysis made on full...... are considered as the input of the estimation process. A comparison is made between the results and also with some in-hand outputs from other estimation sources, e.g., wave radar measurements and sea surface elevation by microwave sensors. The discussed and analyzed procedure could also lead to an automatic...

  9. Autonomous, Computer-Based Behavioral Health Countermeasure Evaluation at HI-SEAS Mars Analog. (United States)

    Anderson, Allison P; Fellows, Abigail M; Binsted, Kim A; Hegel, Mark T; Buckey, Jay C

    Living in an isolated, confined environment (ICE) can induce conflict, stress, and depression. Computer-based behavioral health countermeasures are appealing for training and treatment in ICEs because they provide confidentiality and do not require communication with the outside environment. We evaluated the Virtual Space Station (VSS), a suite of interactive computer-delivered psychological training and treatment programs, at the Hawaii Space Exploration Analog and Simulation (HI-SEAS) III expedition. Six subjects (3 male, 3 female) spent 8 mo in group-isolation and used the Conflict, Stress, and Depression modules in the VSS. Survey evaluations, data collected within the program, and postdeployment interviews were collected. This crew dealt with behavioral health issues common to ICEs. The VSS proved to be a valuable resource and was used both as intended, and in unanticipated ways, to help maintain behavioral health. The Conflict and Stress Modules were rated as highly acceptable (1.8 on a 7-point Likert scale). The crew identified a total of 13 stressors and worked on 9 problems through the VSS. Opinions about the modules were highly individualized. Crewmembers identified exercises in the VSS that were applicable and not applicable to their needs. Additional content to improve the program was identified. Autonomous, confidential training and treatment for behavioral health issues will need to be a critical component of long duration spaceflight travel. This work provides an evaluation of such a tool in a relevant ICE. Anderson AP, Fellows AM, Binsted KA, Hegel MT, Buckey JC. Autonomous, computer-based behavioral health countermeasure evaluation at HI-SEAS Mars analog. Aerosp Med Hum Perform. 2016; 87(11):912-920.

  10. From exemplar to grammar: a probabilistic analogy-based model of language learning. (United States)

    Bod, Rens


    While rules and exemplars are usually viewed as opposites, this paper argues that they form end points of the same distribution. By representing both rules and exemplars as (partial) trees, we can take into account the fluid middle ground between the two extremes. This insight is the starting point for a new theory of language learning that is based on the following idea: If a language learner does not know which phrase-structure trees should be assigned to initial sentences, s/he allows (implicitly) for all possible trees and lets linguistic experience decide which is the "best" tree for each sentence. The best tree is obtained by maximizing "structural analogy" between a sentence and previous sentences, which is formalized by the most probable shortest combination of subtrees from all trees of previous sentences. Corpus-based experiments with this model on the Penn Treebank and the Childes database indicate that it can learn both exemplar-based and rule-based aspects of language, ranging from phrasal verbs to auxiliary fronting. By having learned the syntactic structures of sentences, we have also learned the grammar implicit in these structures, which can in turn be used to produce new sentences. We show that our model mimicks children's language development from item-based constructions to abstract constructions, and that the model can simulate some of the errors made by children in producing complex questions. Copyright © 2009 Cognitive Science Society, Inc.

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

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


    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. PMID:28116132

  12. Computational design of new molecular scaffolds for medicinal chemistry, part II: generalization of analog series-based scaffolds (United States)

    Dimova, Dilyana; Stumpfe, Dagmar; Bajorath, Jürgen


    Aim: Extending and generalizing the computational concept of analog series-based (ASB) scaffolds. Materials & methods: Methodological modifications were introduced to further increase the coverage of analog series (ASs) and compounds by ASB scaffolds. From bioactive compounds, ASs were systematically extracted and second-generation ASB scaffolds isolated. Results: More than 20,000 second-generation ASB scaffolds with single or multiple substitution sites were extracted from active compounds, achieving more than 90% coverage of ASs. Conclusion: Generalization of the ASB scaffold approach has yielded a large knowledge base of scaffold-capturing compound series and target information. PMID:29379641

  13. Modular Hybrid Energy Concept Employing a Novel Control Structure Based on a Simple Analog System

    Directory of Open Access Journals (Sweden)



    Full Text Available This paper proposes a novel control topology which enables the setup of a low cost analog system leading to the implementation of a modular energy conversion system. The modular concept is based on hybrid renewable energy (solar and wind and uses high voltage inverters already available on the market. An important feature of the proposed topology is a permanently active current loop, which assures short circuit protection and simplifies the control loops compensation. The innovative analogue solution of the control structure is based on a dedicated integrated circuit (IC for power factor correction (PFC circuits, used in a new configuration, to assure an efficient inverter start-up. The energy conversion system (control structure and maximum power point tracking algorithm is simulated using a new macromodel-based concept, which reduces the usual computational burden of the simulator and achieves high processing speed. The proposed novel system is presented in this article from concept, through the design and implementation stages, is verified through simulation and is validated by experimental results.

  14. Synthesis and anti-HBV activity of α-stereoisomer of aristeromycin based analogs. (United States)

    Kasula, Mohan; Toyama, Masaaki; Samunuri, Ramakrishnamraju; Rozy, Farhana; Yadav, Monika; Bal, Chandralata; Jha, Ashok Kumar; Baba, Masanori; Sharon, Ashoke


    The potential antiviral activity of aristeromycin type of derivatives (I) is limited by associated toxicity due to its possible 5'-O-phosphorylation and S-adenosyl-l-homocysteine hydrolase (SAHase) inhibitory activity. Aristeromycin structure has major pharmacophoric motif as 5'-OH and adenosine base, which may have significant role in enzyme binding followed by activity and or toxicity. Thus, the structural optimization to alter this major motif by replacing with its bioisostere and changing the 5'-O conformation through stereochemistry reversal was of interest. Thus, the inverted stereochemistry at 4'-position coupled with bioisostere of adenosine base in the target compounds (6-7) to access antiviral potential. The stereoselective formation of a key stereoisomer (2a) was achieved exclusively from neplanocin sugar (1a) by reduction in a single step. The novel target molecules (6-7) were synthesized in 4 steps with 55-62% yield. Compound 6 was analyzed by single crystal X-ray diffraction, which confirms the stereoselective formation of α-analogs with highly puckered cyclopentane ring and 2'-endo conformation. The compound 6 shown significant anti-hepatitis B virus activity of 6.5μM with CC50>100μM and yielded a promising lead with novel structural feature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Supporting Analogy-based Effort Estimation with the Use of Ontologies

    Directory of Open Access Journals (Sweden)

    Joanna Kowalska


    Full Text Available The paper concerns effort estimation of software development projects, in particular, at the level of product delivery stages. It proposes a new approach to model project data to support expert-supervised analogy-based effort estimation. The data is modeled using Semantic Web technologies, such as Resource Description Framework (RDF and Ontology Language for the Web (OWL. Moreover, in the paper, we define a method of supervised case-based reasoning. The method enables to search for similar projects’ tasks at different levels of abstraction. For instance, instead of searching for a task performed by a specific person, one could look for tasks performed by people with similar capabilities. The proposed method relies on ontology that defines the core concepts and relationships. However, it is possible to introduce new classes and relationships, without the need of altering the search mechanisms. Finally, we implemented a prototype tool that was used to preliminary validate the proposed approach. We observed that the proposed approach could potentially help experts in estimating non-trivial tasks that are often underestimated.

  16. Photonics-based multi-function analog signal processor based on a polarization division multiplexing Mach-Zehnder modulator. (United States)

    Zhang, Yamei; Pan, Shilong


    A photonics-based multi-function analog signal processor based on an optical polarization division multiplexing dual-parallel Mach-Zehnder modulator is proposed and demonstrated, which can implement simultaneously photonic microwave phase shifting, upconversion/downconversion and filtering with excellent tunability. An experiment is carried out. Downconverted and upconverted phase shifters with phases continuously tuned from -180 to 180 deg over 0-11 and 11-33 GHz are implemented. Based on the frequency-mixed phase shifter, a four-tap microwave photonic filter that has the capability to select a frequency-mixed component is built. The proposed approach features multi-function, scalable independent channels, a wide bandwidth, and high tunability, which can find applications in beamforming networks, radio frequency frontends, and radio over fiber systems.

  17. VHDL-based programming environment for Floating-Gate analog memory cell

    Directory of Open Access Journals (Sweden)

    Carlos Alberto dos Reis Filho


    Full Text Available An implementation in CMOS technology of a Floating-Gate Analog Memory Cell and Programming Environment is presented. A digital closed-loop control compares a reference value set by user and the memory output and after cycling, the memory output is updated and the new value stored. The circuit can be used as analog trimming for VLSI applications where mechanical trimming associated with postprocessing chip is prohibitive due to high costs.

  18. A New Digital to Analog Converter Based on Low-Offset Bandgap Reference

    Directory of Open Access Journals (Sweden)

    Jinpeng Qiu


    Full Text Available This paper presents a new 12-bit digital to analog converter (DAC circuit based on a low-offset bandgap reference (BGR circuit with two cascade transistor structure and two self-contained feedback low-offset operational amplifiers to reduce the effects of offset operational amplifier voltage effect on the reference voltage, PMOS current-mirror mismatch, and its channel modulation. A Start-Up circuit with self-bias current architecture and multipoint voltage monitoring is employed to keep the BGR circuit working properly. Finally, a dual-resistor ladder DAC-Core circuit is used to generate an accuracy DAC output signal to the buffer operational amplifier. The proposed circuit was fabricated in CSMC 0.5 μm 5 V 1P4M process. The measured differential nonlinearity (DNL of the output voltages is less than 0.45 LSB and integral nonlinearity (INL less than 1.5 LSB at room temperature, consuming only 3.5 mW from a 5 V supply voltage. The DNL and INL at −55°C and 125°C are presented as well together with the discussion of possibility of improving the DNL and INL accuracy in future design.

  19. Optical Flow in a Smart Sensor Based on Hybrid Analog-Digital Architecture

    Directory of Open Access Journals (Sweden)

    Pablo Guzmán


    Full Text Available The purpose of this study is to develop a motion sensor (delivering optical flow estimations using a platform that includes the sensor itself, focal plane processing resources, and co-processing resources on a general purpose embedded processor. All this is implemented on a single device as a SoC (System-on-a-Chip. Optical flow is the 2-D projection into the camera plane of the 3-D motion information presented at the world scenario. This motion representation is widespread well-known and applied in the science community to solve a wide variety of problems. Most applications based on motion estimation require work in real-time; hence, this restriction must be taken into account. In this paper, we show an efficient approach to estimate the motion velocity vectors with an architecture based on a focal plane processor combined on-chip with a 32 bits NIOS II processor. Our approach relies on the simplification of the original optical flow model and its efficient implementation in a platform that combines an analog (focal-plane and digital (NIOS II processor. The system is fully functional and is organized in different stages where the early processing (focal plane stage is mainly focus to pre-process the input image stream to reduce the computational cost in the post-processing (NIOS II stage. We present the employed co-design techniques and analyze this novel architecture. We evaluate the system’s performance and accuracy with respect to the different proposed approaches described in the literature. We also discuss the advantages of the proposed approach as well as the degree of efficiency which can be obtained from the focal plane processing capabilities of the system. The final outcome is a low cost smart sensor for optical flow computation with real-time performance and reduced power consumption that can be used for very diverse application domains.

  20. Optical flow in a smart sensor based on hybrid analog-digital architecture. (United States)

    Guzmán, Pablo; Díaz, Javier; Agís, Rodrigo; Ros, Eduardo


    The purpose of this study is to develop a motion sensor (delivering optical flow estimations) using a platform that includes the sensor itself, focal plane processing resources, and co-processing resources on a general purpose embedded processor. All this is implemented on a single device as a SoC (System-on-a-Chip). Optical flow is the 2-D projection into the camera plane of the 3-D motion information presented at the world scenario. This motion representation is widespread well-known and applied in the science community to solve a wide variety of problems. Most applications based on motion estimation require work in real-time; hence, this restriction must be taken into account. In this paper, we show an efficient approach to estimate the motion velocity vectors with an architecture based on a focal plane processor combined on-chip with a 32 bits NIOS II processor. Our approach relies on the simplification of the original optical flow model and its efficient implementation in a platform that combines an analog (focal-plane) and digital (NIOS II) processor. The system is fully functional and is organized in different stages where the early processing (focal plane) stage is mainly focus to pre-process the input image stream to reduce the computational cost in the post-processing (NIOS II) stage. We present the employed co-design techniques and analyze this novel architecture. We evaluate the system's performance and accuracy with respect to the different proposed approaches described in the literature. We also discuss the advantages of the proposed approach as well as the degree of efficiency which can be obtained from the focal plane processing capabilities of the system. The final outcome is a low cost smart sensor for optical flow computation with real-time performance and reduced power consumption that can be used for very diverse application domains.

  1. Unity and disunity in evolutionary sciences: process-based analogies open common research avenues for biology and linguistics. (United States)

    List, Johann-Mattis; Pathmanathan, Jananan Sylvestre; Lopez, Philippe; Bapteste, Eric


    For a long time biologists and linguists have been noticing surprising similarities between the evolution of life forms and languages. Most of the proposed analogies have been rejected. Some, however, have persisted, and some even turned out to be fruitful, inspiring the transfer of methods and models between biology and linguistics up to today. Most proposed analogies were based on a comparison of the research objects rather than the processes that shaped their evolution. Focusing on process-based analogies, however, has the advantage of minimizing the risk of overstating similarities, while at the same time reflecting the common strategy to use processes to explain the evolution of complexity in both fields. We compared important evolutionary processes in biology and linguistics and identified processes specific to only one of the two disciplines as well as processes which seem to be analogous, potentially reflecting core evolutionary processes. These new process-based analogies support novel methodological transfer, expanding the application range of biological methods to the field of historical linguistics. We illustrate this by showing (i) how methods dealing with incomplete lineage sorting offer an introgression-free framework to analyze highly mosaic word distributions across languages; (ii) how sequence similarity networks can be used to identify composite and borrowed words across different languages; (iii) how research on partial homology can inspire new methods and models in both fields; and (iv) how constructive neutral evolution provides an original framework for analyzing convergent evolution in languages resulting from common descent (Sapir's drift). Apart from new analogies between evolutionary processes, we also identified processes which are specific to either biology or linguistics. This shows that general evolution cannot be studied from within one discipline alone. In order to get a full picture of evolution, biologists and linguists need to

  2. Analog/RF performance analysis of channel engineered high-K gate-stack based junctionless Trigate-FinFET (United States)

    Tayal, Shubham; Nandi, Ashutosh


    In this paper, the effect of channel parameters like channel thickness (TSi) and channel length (Lg) on the analog/RF performance of high-K gate-stack based junctionless Trigate-FinFET (JLT-FinFET) have been studied using TCAD mixed-mode Sentaurus device simulator. It is observed that use of high-K gate dielectric deteriorates the analog/RF performance of the gate-stack based JLT-FinFET. The variation of change in analog/RF FOMs (ΔFOM = FOMK=3.9 - FOMK=40) with respect to channel parameters have been focused throughout this study. It is observed that the deterioration in intrinsic dc gain (ΔAV = (AV(K=3.9) - AV(K=40))) with high-K gate dielectrics aggravates with scaling down of TSi (from 2.31 dB at TSi = 12 nm to 5.2 dB at TSi = 6 nm) but increases marginally with scaling down of Lg (ΔAV = 7.6 dB at Lg = 30 nm and ΔAV = 8.7 dB at Lg = 15 nm). However, the deterioration in maximum oscillation frequency (ΔfMAX) and cut-off frequency (ΔfT) are almost negligible. Moreover, it is also observed that the deterioration in analog/RF FOMs due to high-K gate dielectrics can be reduced by upscaling of interfacial layer thickness (TI). Consequently, higher TI value can be convenient in designing of high-K gate-stack based junctionless Trigate-FinFET at lower TSi for analog/RF applications.

  3. Characterization of facies and permeability patterns in carbonate reservoirs based on outcrop analogs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kerans, C.; Lucia, F.J.; Senger, R.K.; Fogg, G.E.; Nance, H.S.; Hovorka, S.D.


    The primary objective of this research is to develop methods for better describing the three-dimensional geometry of carbonate reservoir flow units as related to conventional or enhanced recovery of oil. San Andres and Grayburg reservoirs were selected for study because of the 13 Bbbl of remaining mobile oil and 17 Bbbl of residual oil in these reservoirs. The key data base is provided by detailed characterization of geologic facies and rock permeability in reservior-scale outcrops of the Permian San Andres Formation in the Guadalupe Mountains of New Mexico. Emphasis is placed on developing an outcrop analog for San Andres strata that can be used as (1) a guide to interpreting the regional and local geologic framework of the subsurface reservoirs (2) a data source illustrating the scales and patterns of variability of rock-fabric facies and petrophysical properties, particularly in lateral dimension, and on scales that cannot be studied during subsurface reservoir characterization. The research approach taken to achieve these objectives utilizes the integration of geologic description, geostatistical techniques, and reservoir flow simulation experiments. Results from this research show that the spatial distribution of facies relative to the waterflood direction can significantly affect how the reservoir produces. Bypassing of unswept oil occurs due to cross flow of injected water from high permeability zones into lower permeability zones were high permeability zones terminate. An area of unswept oil develops because of the slower advance of the water-injection front in the lower permeability zones. When the injection pattern is reversed, the cross-flow effect changes due to the different arrangements of rock-fabric flow units relative to the flow of injected water, and the sweep efficiency is significantly different. Flow across low-permeability mudstones occurs showing that these layers do not necessarily represent flow barriers.

  4. Achiral Mannich-Base Curcumin Analogs Induce Unfolded Protein Response and Mitochondrial Membrane Depolarization in PANC-1 Cells

    Directory of Open Access Journals (Sweden)

    Gábor J. Szebeni


    Full Text Available Achiral Mannich-type curcumin analogs have been synthetized and assayed for their cytotoxic activity. The anti-proliferative and cytotoxic activity of curcuminoids has been tested on human non-small-cell lung carcinoma (A549, hepatocellular carcinoma (HepG2 and pancreatic cancer cell line (PANC-1. Based on the highest anti-proliferative activity nine drug candidates were further tested and proved to cause phosphatidylserine exposure as an early sign of apoptosis. Curcumin analogs with the highest apoptotic activity were selected for mechanistic studies in the most sensitive PANC-1 cells. Cytotoxic activity was accompanied by cytostatic effect since curcumin and analogs treatment led to G0/G1 cell cycle arrest. Moreover, cytotoxic effect could be also detected via the accumulation of curcuminoids in the endoplasmic reticulum (ER and the up-regulation of ER stress-related unfolded protein response (UPR genes: HSPA5, ATF4, XBP1, and DDIT3. The activated UPR induced mitochondrial membrane depolarization, caspase-3 activation and subsequent DNA breakdown in PANC-1 cells. Achiral curcumin analogs, C509, C521 and C524 possessed superior, 40-times more potent cytotoxic activity compared to natural dihydroxy-dimetoxycurcumin in PANC-1 cells.

  5. Teaching Radioactive Decay and Radiometric Dating: An Analog Activity Based on Fluid Dynamics (United States)

    Claiborne, Lily L.; Miller, Calvin F.


    We present a new laboratory activity for teaching radioactive decay by using hydrodynamic processes as an analog and an evaluation of its efficacy in the classroom. A fluid flowing from an upper beaker into a lower beaker (shampoo in this case) behaves mathematically identically to radioactive decay, mimicking the exponential decay process,…

  6. How Science Students Can Learn about Unobservable Phenomena Using Computer-Based Analogies (United States)

    Trey, L.; Khan, S.


    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…

  7. Detecting lung cancer symptoms with analogic CNN algorithms based on a constrained diffusion template

    International Nuclear Information System (INIS)

    Hirakawa, Satoshi; Nishio, Yoshifumi; Ushida, Akio; Ueno, Junji; Kasem, I.; Nishitani, Hiromu; Rekeczky, C.; Roska, T.


    In this article, a new type of diffusion template and an analogic CNN algorithm using this diffusion template for detecting some lung cancer symptoms in X-ray films are proposed. The performance of the diffusion template is investigated and our CNN algorithm is verified to detect some key lung cancer symptoms, successfully. (author)

  8. Genome-wide screening for genes whose deletions confer sensitivity to mutagenic purine base analogs in yeast

    Directory of Open Access Journals (Sweden)

    Kozmin Stanislav G


    Full Text Available Abstract Background N-hydroxylated base analogs, such as 6-hydroxylaminopurine (HAP and 2-amino-6-hydroxylaminopurine (AHA, are strong mutagens in various organisms due to their ambiguous base-pairing properties. The systems protecting cells from HAP and related noncanonical purines in Escherichia coli include specialized deoxyribonucleoside triphosphatase RdgB, DNA repair endonuclease V, and a molybdenum cofactor-dependent system. Fewer HAP-detoxification systems have been identified in yeast Saccharomyces cerevisiae and other eukaryotes. Cellular systems protecting from AHA are unknown. In the present study, we performed a genome-wide search for genes whose deletions confer sensitivity to HAP and AHA in yeast. Results We screened the library of yeast deletion mutants for sensitivity to the toxic and mutagenic action of HAP and AHA. We identified novel genes involved in the genetic control of base analogs sensitivity, including genes controlling purine metabolism, cytoskeleton organization, and amino acid metabolism. Conclusion We developed a method for screening the yeast deletion library for sensitivity to the mutagenic and toxic action of base analogs and identified 16 novel genes controlling pathways of protection from HAP. Three of them also protect from AHA.

  9. A Physical Analog Model of Strike-Slip Faulting for Model-Based Inquiry in the Classroom (United States)

    Curren, I. S.; Glesener, G.


    classroom setting. We hope to encourage discussion from session attendees on the use of physical analog models and real-time quantitative model-based inquiry in the development of the next generation of geoscientists.

  10. Evaluation of Cobalt-Labeled Octreotide Analogs for Molecular Imaging and Auger Electron-Based Radionuclide Therapy

    DEFF Research Database (Denmark)

    Thisgaard, Helge; Olsen, Birgitte Brinkmann; Dam, Johan Hygum


    The somatostatin receptor, which is overexpressed by many neuroendocrine tumors, is a well-known target for molecular imaging and peptide receptor radionuclide therapy. Recently, (57)Co-labeled DOTATOC, an octreotide analog, was shown to have the highest affinity yet found for somatostatin receptor...... subtype 2. The aim of this study was to evaluate the biologic effects of novel cobalt-labeled octreotide analogs targeting the somatostatin receptor to identify promising candidates for molecular imaging and Auger electron-based radionuclide therapy. METHODS: Cobalt-labeled DOTATATE, DOTATOC, and DOTANOC...... were prepared with (57)Co or (58m)Co for SPECT or Auger electron-based therapy, respectively. The cellular uptake and intracellular distribution of the radioligands were characterized with the pancreatic tumor cell line AR42J in vitro, including assessment of the therapeutic effects of (58m...

  11. Mechanical Analogy-based Iterative Method for Solving a System of Linear Equations

    Directory of Open Access Journals (Sweden)

    Yu. V. Berchun


    Full Text Available The paper reviews prerequisites to creating a variety of the iterative methods to solve a system of linear equations (SLE. It considers the splitting methods, variation-type methods, projection-type methods, and the methods of relaxation.A new iterative method based on mechanical analogy (the movement without resistance of a material point, that is connected by ideal elastically-linear constraints with unending guides defined by equations of solved SLE. The mechanical system has the unique position of stable equilibrium, the coordinates of which correspond to the solution of linear algebraic equation. The model of the mechanical system is a system of ordinary differential equations of the second order, integration of which allows you to define the point trajectory. In contrast to the classical methods of relaxation the proposed method does not ensure a trajectory passage through the equilibrium position. Thus the convergence of the method is achieved through the iterative stop of a material point at the moment it passes through the next (from the beginning of the given iteration minimum of potential energy. After that the next iteration (with changed initial coordinates starts.A resource-intensive process of numerical integration of differential equations in order to obtain a precise law of motion (at each iteration is replaced by defining its approximation. The coefficients of the approximating polynomial of the fourth order are calculated from the initial conditions, including higher-order derivatives. The resulting approximation enables you to evaluate the kinetic energy of a material point to calculate approximately the moment of time to reach the maximum kinetic energy (and minimum of the potential one, i.e. the end of the iteration.The software implementation is done. The problems with symmetric positive definite matrix, generated as a result of using finite element method, allowed us to examine a convergence rate of the proposed method

  12. Space Station Habitability Recommendations Based on a Systematic Comparative Analysis of Analogous Conditions (United States)

    Stuster, Jack W.


    Conditions analogous to the proposed NASA Space Station are systematically analyzed in order to extrapolate design guidelines and recommendations concerning habitability and crew productivity. Analogous environments studied included Skylab, Sealab, Tektite, submarines, Antarctic stations and oil drilling platforms, among others. These analogues were compared and rated for size and composition of group, social organization, preparedness for mission, duration of tour, types of tasks, physical and psychological isolation, personal motivation, perceived risk, and quality of habitat and life support conditions. One-hundred design recommendations concerning, sleep, clothing, exercise, medical support, personal hygiene, food preparation, group interaction, habitat aesthetics, outside communications, recreational opportunities, privacy and personal space, waste disposal, onboard training, simulation and task preparation, and behavioral and physiological requirements associated with a microgravity environment, are provided.

  13. Mars extant-life campaign using an approach based on Earth-analog habitats (United States)

    Palkovic, Lawrence A.; Wilson, Thomas J.


    The Mars Robotic Outpost group at JPL has identified sixteen potential momentous discoveries that if found on Mars would alter planning for the future Mars exploration program. This paper details one possible approach to the discovery of and response to the 'momentous discovery'' of extant life on Mars. The approach detailed in this paper, the Mars Extant-Life (MEL) campaign, is a comprehensive and flexible program to find living organisms on Mars by studying Earth-analog habitats of extremophile communities.

  14. A QSAR study on the inhibition mechanism of matrix metalloproteinase-12 by arylsulfone analogs based on molecular orbital calculations. (United States)

    Hitaoka, Seiji; Chuman, Hiroshi; Yoshizawa, Kazunari


    A binding mechanism between human matrix metalloproteinase-12 (MMP-12) and eight arylsulfone analogs having two types of carboxylic and hydroxamic acids as the most representative zinc binding group is investigated using a quantitative structure-activity relationship (QSAR) analysis based on a linear expression by representative energy terms (LERE). The LERE-QSAR analysis quantitatively reveals that the variation in the observed (experimental) inhibitory potency among the arylsulfone analogs is decisively governed by those in the intrinsic binding and dispersion interaction energies. The results show that the LERE-QSAR analysis not only can excellently reproduce the observed overall free-energy change but also can determine the contributions of representative free-energy changes. An inter-fragment interaction energy difference (IFIED) analysis based on the fragment molecular orbital (FMO) method (FMO-IFIED) leads to the identification of key residues governing the variation in the inhibitory potency as well as to the understanding of the difference between the interactions of the carboxylic and hydroxamic acid zinc binding groups. The current results that have led to the optimization of the inhibitory potency of arylsulfone analogs toward MMP-12 to be used in the treatment of chronic obstructive pulmonary disease may be useful for the development of a new potent MMP-12 inhibitor.

  15. Analog fourier transform channelizer and OFDM receiver



    An OFDM receiver having an analog multiplier based I-Q channelizing filter, samples and holds consecutive analog I-Q samples of an I-Q baseband, the I-Q basebands having OFDM sub-channels. A lattice of analog I-Q multipliers and analog I-Q summers concurrently receives the held analog I-Q samples, performs analog I-Q multiplications and analog I-Q additions to concurrently generate a plurality of analog I-Q output signals, representing an N-point discrete Fourier transform of the held analog ...

  16. Inductive, Analogical, and Communicative Generalization

    Directory of Open Access Journals (Sweden)

    Adri Smaling


    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.

  17. Analog earthquakes

    International Nuclear Information System (INIS)

    Hofmann, R.B.


    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

  18. Design and implementation of a reconfigurable mixed-signal SoC based on field programmable analog arrays (United States)

    Liu, Lintao; Gao, Yuhan; Deng, Jun


    This work presents a reconfigurable mixed-signal system-on-chip (SoC), which integrates switched-capacitor-based field programmable analog arrays (FPAA), analog-to-digital converter (ADC), digital-to-analog converter, digital down converter , digital up converter, 32-bit reduced instruction-set computer central processing unit (CPU) and other digital IPs on a single chip with 0.18 μm CMOS technology. The FPAA intellectual property could be reconfigured as different function circuits, such as gain amplifier, divider, sine generator, and so on. This single-chip integrated mixed-signal system is a complete modern signal processing system, occupying a die area of 7 × 8 mm 2 and consuming 719 mW with a clock frequency of 150 MHz for CPU and 200 MHz for ADC/DAC. This SoC chip can help customers to shorten design cycles, save board area, reduce the system power consumption and depress the system integration risk, which would afford a big prospect of application for wireless communication. Project supported by the National High Technology and Development Program of China (No. 2012AA012303).

  19. European Forest Cover During the Past 12,000 Years: A Palynological Reconstruction Based on Modern Analogs and Remote Sensing

    Directory of Open Access Journals (Sweden)

    Marco Zanon


    Full Text Available Characterization of land cover change in the past is fundamental to understand the evolution and present state of the Earth system, the amount of carbon and nutrient stocks in terrestrial ecosystems, and the role played by land-atmosphere interactions in influencing climate. The estimation of land cover changes using palynology is a mature field, as thousands of sites in Europe have been investigated over the last century. Nonetheless, a quantitative land cover reconstruction at a continental scale has been largely missing. Here, we present a series of maps detailing the evolution of European forest cover during last 12,000 years. Our reconstructions are based on the Modern Analog Technique (MAT: a calibration dataset is built by coupling modern pollen samples with the corresponding satellite-based forest-cover data. Fossil reconstructions are then performed by assigning to every fossil sample the average forest cover of its closest modern analogs. The occurrence of fossil pollen assemblages with no counterparts in modern vegetation represents a known limit of analog-based methods. To lessen the influence of no-analog situations, pollen taxa were converted into plant functional types prior to running the MAT algorithm. We then interpolate site-specific reconstructions for each timeslice using a four-dimensional gridding procedure to create continuous gridded maps at a continental scale. The performance of the MAT is compared against methodologically independent forest-cover reconstructions produced using the REVEALS method. MAT and REVEALS estimates are most of the time in good agreement at a trend level, yet MAT regularly underestimates the occurrence of densely forested situations, requiring the application of a bias correction procedure. The calibrated MAT-based maps draw a coherent picture of the establishment of forests in Europe in the Early Holocene with the greatest forest-cover fractions reconstructed between ∼8,500 and 6

  20. Analog design centering and sizing

    CERN Document Server

    Graeb, Helmut E


    Here is a compendium of fundamental problem formulations of analog design centering and sizing. It provides a differentiated knowledge about the many tasks of analog design centering and sizing. In particular, coverage formulates the worst-case problem. The book stands at the interface between process technology and design technology, detailing how the two are required to reach a solution. It presents a mathematically founded description based on numerical optimization and statistics. This volume will enable analog and mixed-signal designers to assess CAD solution methods that are presented to them as well as help developers of analog CAD tools to formulate and develop solution approaches for analog design centering and sizing.

  1. Alternate source term models for Yucca Mountain performance assessment based on natural analog data and secondary mineral solubility

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, W.M.; Codell, R.B.


    Performance assessment calculations for the proposed high level radioactive waste repository at Yucca Mountain, Nevada, were conducted using the Nuclear Regulatory Commission Total-System Performance Assessment (TPA 3.2) code to test conceptual models and parameter values for the source term based on data from the Pena Blanca, Mexico, natural analog site and based on a model for coprecipitation and solubility of secondary schoepite. In previous studies the value for the maximum constant oxidative alteration rate of uraninite at the Nopal I uranium body at Pena Blanca was estimated. Scaling this rate to the mass of uranium for the proposed Yucca Mountain repository yields an oxidative alteration rate of 22 kg/y, which was assumed to be an upper limit on the release rate from the proposed repository. A second model was developed assuming releases of radionuclides are based on the solubility of secondary schoepite as a function of temperature and solution chemistry. Releases of uranium are given by the product of uranium concentrations at equilibrium with schoepite and the flow of water through the waste packages. For both models, radionuclides other than uranium and those in the cladding and gap fraction were modeled to be released at a rate proportional to the uranium release rate, with additional elemental solubility limits applied. Performance assessment results using the Pena Blanca oxidation rate and schoepite solubility models for Yucca Mountain were compared to the TPA 3.2 base case model, in which release was based on laboratory studies of spent fuel dissolution, cladding and gap release, and solubility limits. Doses calculated using the release rate based on natural analog data and the schoepite solubility models were smaller than doses generated using the base case model. These results provide a degree of confidence in safety predictions using the base case model and an indication of how conservatism in the base case model may be reduced in future analyses.

  2. Cyber Analogies (United States)


    strategic thinking about cy- berwar reflects an awareness that this duality applies to the virtual domain as well. The history of air campaigns over sciences he iden- tifies analogies in the realms of biodiversity and herd immunity . And then he flips the (seemingly unusable) notion of economic...suggests that diver- sity of cyber systems makes the defense as weak as its weakest component. 30. Herd Immunity If a sufficient proportion of the

  3. A Comparison between Physics-based and Polytropic MHD Models for Stellar Coronae and Stellar Winds of Solar Analogs

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, O. [Lowell Center for Space Science and Technology, University of Massachusetts, Lowell, MA 01854 (United States)


    The development of the Zeeman–Doppler Imaging (ZDI) technique has provided synoptic observations of surface magnetic fields of low-mass stars. This led the stellar astrophysics community to adopt modeling techniques that have been used in solar physics using solar magnetograms. However, many of these techniques have been neglected by the solar community due to their failure to reproduce solar observations. Nevertheless, some of these techniques are still used to simulate the coronae and winds of solar analogs. Here we present a comparative study between two MHD models for the solar corona and solar wind. The first type of model is a polytropic wind model, and the second is the physics-based AWSOM model. We show that while the AWSOM model consistently reproduces many solar observations, the polytropic model fails to reproduce many of them, and in the cases where it does, its solutions are unphysical. Our recommendation is that polytropic models, which are used to estimate mass-loss rates and other parameters of solar analogs, must first be calibrated with solar observations. Alternatively, these models can be calibrated with models that capture more detailed physics of the solar corona (such as the AWSOM model) and that can reproduce solar observations in a consistent manner. Without such a calibration, the results of the polytropic models cannot be validated, but they can be wrongly used by others.

  4. A Study of an Architecture Design Learning Process Based on Social Learning, Course Teaching, Interaction, and Analogical Thinking

    Directory of Open Access Journals (Sweden)

    Yun-Wu Wu


    Full Text Available The students in the vocational education of architecture design in Taiwan often face many learning obstacles, such as no problem solving ability and lack of creativity. Therefore, this study used a social learning model as a learning strategy in the architecture design learning process to solve related learning difficulties. Firstly, this study used cognitive development teaching activities and a learning process based on analogical thinking and analogical reasoning to build the social learning model. Secondly, the social learning model of this study was implemented in the teaching of a required course of architecture design for 120 freshmen in China University of Technology. The questionnaire survey results were then statically analyzed and compared to measure the differences in the students’ knowledge about architecture designs before and after the teaching in this study. In this study, the social learning model is proven helpful in inspiring the students’ creativity by converting new knowledge of architecture design into schemas and hence retaining the new knowledge for future application. The social learning model can be applied in the teaching of architecture design in other schools, while more research can be conducted in the future to further confirm its feasibility to promote effective learning.

  5. Fault Modeling and Testing for Analog Circuits in Complex Space Based on Supply Current and Output Voltage

    Directory of Open Access Journals (Sweden)

    Hongzhi Hu


    Full Text Available This paper deals with the modeling of fault for analog circuits. A two-dimensional (2D fault model is first proposed based on collaborative analysis of supply current and output voltage. This model is a family of circle loci on the complex plane, and it simplifies greatly the algorithms for test point selection and potential fault simulations, which are primary difficulties in fault diagnosis of analog circuits. Furthermore, in order to reduce the difficulty of fault location, an improved fault model in three-dimensional (3D complex space is proposed, which achieves a far better fault detection ratio (FDR against measurement error and parametric tolerance. To address the problem of fault masking in both 2D and 3D fault models, this paper proposes an effective design for testability (DFT method. By adding redundant bypassing-components in the circuit under test (CUT, this method achieves excellent fault isolation ratio (FIR in ambiguity group isolation. The efficacy of the proposed model and testing method is validated through experimental results provided in this paper.

  6. Rover-Based Instrumentation and Scientific Investigations During the 2012 Analog Field Test on Mauna Kea Volcano, Hawaii (United States)

    Graham, L. D.; Graff, T. G.


    Rover-based 2012 Moon and Mars Analog Mission Activities (MMAMA) were recently completed on Mauna Kea Volcano, Hawaii. Scientific investigations, scientific input, and operational constraints were tested in the context of existing project and protocols for the field activities designed to help NASA achieve the Vision for Space Exploration [1]. Several investigations were conducted by the rover mounted instruments to determine key geophysical and geochemical properties of the site, as well as capture the geological context of the area and the samples investigated. The rover traverse and associated science investigations were conducted over a three day period on the southeast flank of the Mauna Kea Volcano, Hawaii. The test area was at an elevation of 11,500 feet and is known as "Apollo Valley" (Fig. 1). Here we report the integration and operation of the rover-mounted instruments, as well as the scientific investigations that were conducted.

  7. Silicon-on-insulator narrow-passband filter based on cascaded MZIs incorporating enhanced FSR for downconverting analog photonic links. (United States)

    Yu, Hongchen; Chen, Minghua; Li, Pengxiao; Yang, Sigang; Chen, Hongwei; Xie, Shizhong


    A silicon-on-insulator (SOI) narrow-passband filter based on cascaded Mach-Zehnder interferometers (MZIs) is theoretically simulated and experimentally demonstrated, indicating that the free spectral range (FSR) of the proposed filter can be significantly enlarged by increasing the number of the MZI stages. A filter using three-stage cascaded MZIs structure is successfully realized in the experiment and a 3-dB bandwidth of about 1.536 GHz and FSR about 13.5 GHz have been achieved. The performance of a downconverting analog photonic link (APL) employing the designed filter for microwave signal processing is also measured and a spurious free dynamic range (SFDR) as high as 104.1dB-Hz(2/3) is observed.

  8. Using Conceptual Change Texts with Analogies for Misconceptions in Acids and Bases (United States)

    Cetingul, Ipek; Geban, Omer


    This study was conducted to explore the effectiveness of conceptual change oriented instruction over traditional instruction on students' understanding of acids and bases concept. Besides, effects of gender difference and science process skills on students' understanding of acids and bases were also investigated. Analysis of the results showed…

  9. Quantum Analog Computing (United States)

    Zak, M.


    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.

  10. Superconductivity in SnO: A Nonmagnetic Analog to Fe-Based Superconductors?

    DEFF Research Database (Denmark)

    Forthaus, M. K.; Sengupta, K.; Heyer, O.


    and superconductivity disappears for p≳16  GPa. It is further shown from band structure calculations that SnO under pressure exhibits a Fermi surface topology similar to that reported for some Fe-based superconductors and that the nesting between the hole and electron pockets correlates with the change of Tc...

  11. A Loudness Function for Analog and Digital Sound Systems based on Equal Loudness Level Contours

    DEFF Research Database (Denmark)

    Nielsen, Sofus Birkedal


    A new and better loudness compensation has been designed based on the differences between the Equal Loudness Level Contours (ELLC) in ISO 226:2003. Sound productions are normally being mixed at a high mixing level (ML) but often played at lower listening level (LL) which mean that the perceived...... solution is realized in a 16/32 bit fixed point DSP and could be implemented in any sound producing system....

  12. Time-to-digital converter based on analog time expansion for 3D time-of-flight cameras (United States)

    Tanveer, Muhammad; Nissinen, Ilkka; Nissinen, Jan; Kostamovaara, Juha; Borg, Johan; Johansson, Jonny


    This paper presents an architecture and achievable performance for a time-to-digital converter, for 3D time-of-flight cameras. This design is partitioned in two levels. In the first level, an analog time expansion, where the time interval to be measured is stretched by a factor k, is achieved by charging a capacitor with current I, followed by discharging the capacitor with a current I/k. In the second level, the final time to digital conversion is performed by a global gated ring oscillator based time-to-digital converter. The performance can be increased by exploiting its properties of intrinsic scrambling of quantization noise and mismatch error, and first order noise shaping. The stretched time interval is measured by counting full clock cycles and storing the states of nine phases of the gated ring oscillator. The frequency of the gated ring oscillator is approximately 131 MHz, and an appropriate stretch factor k, can give a resolution of ≍ 57 ps. The combined low nonlinearity of the time stretcher and the gated ring oscillator-based time-to-digital converter can achieve a distance resolution of a few centimeters with low power consumption and small area occupation. The carefully optimized circuit configuration achieved by using an edge aligner, the time amplification property and the gated ring oscillator-based time-to-digital converter may lead to a compact, low power single photon configuration for 3D time-of-flight cameras, aimed for a measurement range of 10 meters.

  13. Regulation of the Contribution of Integrin to Cell Attachment on Poly(2-Methoxyethyl Acrylate (PMEA Analogous Polymers for Attachment-Based Cell Enrichment.

    Directory of Open Access Journals (Sweden)

    Takashi Hoshiba

    Full Text Available Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate (PMEA substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate (PBA and poly(tetrahydrofurfuryl acrylate (PTHFA, on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy ethyl acrylate-co-butyl acrylate (30:70 mol%, PMe2A and poly(2-(2-methoxyethoxy ethoxy ethyl acrylate-co-butyl acrylate (30:70 mol%, PMe3A, which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment.

  14. Novel Indole-Based Analogs of Melatonin: Synthesis and in Vitro Antioxidant Activity Studies

    Directory of Open Access Journals (Sweden)

    Hanif Shirinzadeh


    Full Text Available The aim of this study was to synthesize and examine possible in vitro antioxidant effects of indole-based melatonin analogue compounds. As a part of our ongoing study nineteen indole hydrazide/hydrazone derivatives were synthesized, characterized and their in vitro antioxidant activity was investigated by three different assays: by evaluating their reducing effect against oxidation of a redox sensitive fluorescent probe, by examining their protective effect against H2O2-induced membrane lipid peroxidation and by determining their inhibitory effect on AAPH–induced hemolysis of human erythrocytes. The results indicated significant strong antioxidant activity for most of the compounds, when compared to melatonin.

  15. Test Point Selection Method for Analog Circuit Fault Diagnosis Based on Similarity Coefficient

    Directory of Open Access Journals (Sweden)

    Qingfeng Ma


    Full Text Available The demand for testability analysis has increased with the integration densities and complexity of circuits. As an important part of testability analysis, the test point selection method needs to be researched in depth. A new similarity coefficient criterion is proposed to determine the fault isolation degree because output responses of a circuit with component tolerance are approximately subject to the normal distribution. Then, a new test point selection method is proposed based on the fault-pair similarity coefficient criterion information table. Simulation experiments are used to validate the accuracy of the proposed method in terms of the optimum test point set and fault isolation degree. The results show that the proposed method improves the performance of test point selection by comparing with the other reported methods.

  16. Are all analogies created equal? Prefrontal cortical functioning may predict types of analogical reasoning. (United States)

    Chrysikou, Evangelia G; Thompson-Schill, Sharon L


    Abstract The proposed theory can account for analogies based on learned relationships between elements in the source and target domains. However, its explanatory power regarding the discovery of new relationships during analogical reasoning is limited. We offer an alternative perspective for the role of PFC in analogical thought that may better address different types of analogical mappings.

  17. Dual delivery systems based on polyamine analog BENSpm as prodrug and gene delivery vectors (United States)

    Zhu, Yu

    Combination drug and gene therapy shows promise in cancer treatment. However, the success of such strategy requires careful selection of the therapeutic agents, as well as development of efficient delivery vectors. BENSpm (N 1, N11-bisethylnorspermine), a polyamine analogue targeting the intracellular polyamine pathway, draws our special attention because of the following reasons: (1) polyamine pathway is frequently dysregulated in cancer; (2) BENSpm exhibits multiple functions to interfere with the polyamine pathway, such as to up-regulate polyamine metabolism enzymes and down-regulate polyamine biosynthesis enzymes. Therefore BENSpm depletes all natural polyamines and leads to apoptosis and cell growth inhibition in a wide range of cancers; (3) preclinical studies proved that BENSpm can act synergistically with various chemotherapy agents, making it a promising candidate in combination therapy; (4) multiple positive charges in BENSpm enable it as a suitable building block for cationic polymers, which can be further applied to gene delivery. In this dissertation, our goal was to design dual-function delivery vector based on BENSpm that can function as a gene delivery vector and, after intracellular degradation, as an active anticancer agent targeting dysregulated polyamine metabolism. We first demonstrated strong synergism between BENSpm and a potential therapeutic gene product TRAIL. Strong synergism was obtained in both estrogen-dependent MCF-7 breast cancer cells and triple-negative MDA-MB-231 breast cancer cells. Significant dose reduction of TRAIL in combination with BENSpm in MDA-MB-231 cells, together with the fact that BENSpm rendered MCF-7 cells more sensitive to TRAIL treatment verified our rationale of designing BENSpm-based delivery platform. This was expected to be beneficial for overcoming drug resistance in chemotherapy, as well as boosting the therapeutic effect of therapeutic genes. We first designed a lipid-based BENSpm dual vector (Lipo

  18. Evaluation of cobalt-labeled octreotide analogs for molecular imaging and auger electron-based radionuclide therapy. (United States)

    Thisgaard, Helge; Olsen, Birgitte Brinkmann; Dam, Johan Hygum; Bollen, Peter; Mollenhauer, Jan; Høilund-Carlsen, Poul Flemming


    The somatostatin receptor, which is overexpressed by many neuroendocrine tumors, is a well-known target for molecular imaging and peptide receptor radionuclide therapy. Recently, (57)Co-labeled DOTATOC, an octreotide analog, was shown to have the highest affinity yet found for somatostatin receptor subtype 2. The aim of this study was to evaluate the biologic effects of novel cobalt-labeled octreotide analogs targeting the somatostatin receptor to identify promising candidates for molecular imaging and Auger electron-based radionuclide therapy. Cobalt-labeled DOTATATE, DOTATOC, and DOTANOC were prepared with (57)Co or (58m)Co for SPECT or Auger electron-based therapy, respectively. The cellular uptake and intracellular distribution of the radioligands were characterized with the pancreatic tumor cell line AR42J in vitro, including assessment of the therapeutic effects of (58m)Co-DOTATATE via DNA double-strand break and proliferation assays. Comparisons with the therapeutic effects of (111)In- and (177)Lu-DOTATATE were also performed. Tumor uptake and normal tissue uptake were characterized in a subcutaneous pancreatic tumor mouse model. All 3 cobalt-conjugated peptides resulted in time-dependent and receptor-specific uptake, with a high level (≥88%) of cellular internalization in vitro of the total cell-associated radioactivity. The DNA double-strand break yield showed a dose-dependent increase with activity, whereas cell survival showed a dose-dependent decrease. (58m)Co-DOTATATE was significantly more efficient in cell killing per cumulated decay than (111)In- and (177)Lu-DOTATATE. The in vivo pharmacokinetic studies showed a high level of receptor-specific tumor uptake. All cobalt-labeled radioligands showed a high level of receptor-specific uptake both in vitro and in vivo in tumor-bearing mice. Furthermore, (58m)Co-DOTATATE showed considerable therapeutic effects in vitro and, thus, could be an effective agent for eradicating disseminated tumor cells and

  19. Elevated Levels of DNA Strand Breaks Induced by a Base Analog in the Human Cell Line with the P32T ITPA Variant (United States)

    Waisertreiger, Irina S.-R.; Menezes, Miriam R.; Randazzo, James; Pavlov, Youri I.


    Base analogs are powerful antimetabolites and dangerous mutagens generated endogenously by oxidative stress, inflammation, and aberrant nucleotide biosynthesis. Human inosine triphosphate pyrophosphatase (ITPA) hydrolyzes triphosphates of noncanonical purine bases (i.e., ITP, dITP, XTP, dXTP, or their mimic: 6-hydroxyaminopurine (HAP) deoxynucleoside triphosphate) and thus regulates nucleotide pools and protects cells from DNA damage. We demonstrate that the model purine base analog HAP induces DNA breaks in human cells and leads to elevation of levels of ITPA. A human polymorphic allele of the ITPA, 94C->A encodes for the enzyme with a P32T amino-acid change and leads to accumulation of nonhydrolyzed ITP. The polymorphism has been associated with adverse reaction to purine base-analog drugs. The level of both spontaneous and HAP-induced DNA breaks is elevated in the cell line with the ITPA P32T variant. The results suggested that human ITPA plays a pivotal role in the protection of DNA from noncanonical purine base analogs. PMID:20936128

  20. Elevated Levels of DNA Strand Breaks Induced by a Base Analog in the Human Cell Line with the P32T ITPA Variant

    Directory of Open Access Journals (Sweden)

    Irina S.-R. Waisertreiger


    Full Text Available Base analogs are powerful antimetabolites and dangerous mutagens generated endogenously by oxidative stress, inflammation, and aberrant nucleotide biosynthesis. Human inosine triphosphate pyrophosphatase (ITPA hydrolyzes triphosphates of noncanonical purine bases (i.e., ITP, dITP, XTP, dXTP, or their mimic: 6-hydroxyaminopurine (HAP deoxynucleoside triphosphate and thus regulates nucleotide pools and protects cells from DNA damage. We demonstrate that the model purine base analog HAP induces DNA breaks in human cells and leads to elevation of levels of ITPA. A human polymorphic allele of the ITPA, 94C->A encodes for the enzyme with a P32T amino-acid change and leads to accumulation of nonhydrolyzed ITP. The polymorphism has been associated with adverse reaction to purine base-analog drugs. The level of both spontaneous and HAP-induced DNA breaks is elevated in the cell line with the ITPA P32T variant. The results suggested that human ITPA plays a pivotal role in the protection of DNA from noncanonical purine base analogs.

  1. Novel acyclonucleoside analog bearing a 1,2,4-triazole–Schiff base: Synthesis, characterization and analytical studies using square wave-adsorptive stripping voltammetry and HPLC


    Ali F. Alghamdi; Nadjet Rezki


    New acyclonucleoside analogs tethered by a 1,2,4-triazole scaffold were synthesized through the condensation of 4-amino-5-(2-phenyleth-1-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (2) with benzaldehyde followed by the alkylation of the resulting Schiff base (3)with 2-bromoethanol, 3-chloropropanol and/or 3-chloropropan-1,2-diol. Voltammetric studies were carried out for the analysis of 1 × 10−6 mol L−1 of the newly synthesized acyclonucleoside analogs (4–6) using square wave-adsorptive stripp...

  2. Charge-plasma based dual-material and gate-stacked architecture of junctionless transistor for enhanced analog performance (United States)

    Amin, S. Intekhab; Sarin, R. K.


    Charge plasma based doping-less dual material double gate (DL-DMDG) junctionless transistor (JLT) is proposed. This paper also demonstrate the potential impact of gate stacking (GS) (high-k + Sio2) on DL-DMDG (DL-GSDMDG) JLT device. The efficient charge plasma is created in an intrinsic silicon film to form n + source/drain (S/D) by selecting proper work function of S/D electrode which helps to minimize threshold voltage fluctuation that occurs in a heavily doped JLT device. The analog performance parameters are analyzed for both the device structures. Results are also compared with conventional dual material double gate (DMDG) and gate stacked dual material double gate (GSDMDG) JLT devices. A DL-DMDG JLT device shows improved early voltage (VEA), intrinsic gain (AV = gm/gDS) and reduced output conductance (gDS) as compared to conventional DMDG and GSDMDG JLT devices. These values are further improved for DL-GSDMDG JLT. The effect of control gate length (L1) for a fixed gate length (L = L1+L2) are also analyzed.

  3. Analysis by NASA's VESGEN Software of Vascular Branching in the Human Retina with a Ground-Based Microgravity Analog (United States)

    Parsons-Wingerter, Patricia; Vyas, Ruchi J.; Raghunandan, Sneha; Vu, Amanda C.; Zanello, Susana B.; Ploutz-Snyder, Robert; Taibbi, Giovanni; Vizzeri, Gianmarco


    Significant risks for visual impairment were discovered recently in astronauts following spaceflight, especially after long-duration missions.1 We hypothesize that microgravity-induced fluid shifts result in pathological changes within the retinal vasculature that precede visual and other ocular impairments. We therefore are analyzing retinal vessels in healthy subjects with NASA's VESsel GENeration Analysis (VESGEN) software2 before and after head-down tilt (HDT), a ground-based microgravity analog For our preliminary study of masked images, two groups of venous trees with and without small veins (G=7) were clearly identified by VESGEN analysis. Upon completing all images and unmasking the subject status of pre- and post- HDT, we will determine whether differences in the presence or absence of small veins are important correlates, and perhaps reliable predictors, of other ocular and physiological adaptations to prolonged HDT and microgravity. Greater peripapillary retinal thickening was measured following 70-day HDT bed rest than 14-day HDT bed rest, suggesting that time of HDT may increase the amount of optic disc swelling.3 Spectralis OCT detected retinal nerve fiber layer thickening post HDT, without clinical signs of optic disc edema. Such changes may have resulted from HDT-induced cephalad fluid shifts. Clinical methods for examining adaptive microvascular remodeling in the retina to microgravity space flight are currently not established.

  4. Potential applications of curcumin and its novel synthetic analogs and nanotechnology-based formulations in cancer prevention and therapy

    Directory of Open Access Journals (Sweden)

    Batra Surinder K


    Full Text Available Abstract Curcumin has attracted great attention in the therapeutic arsenal in clinical oncology due to its chemopreventive, antitumoral, radiosensibilizing and chemosensibilizing activities against various types of aggressive and recurrent cancers. These malignancies include leukemias, lymphomas, multiple myeloma, brain cancer, melanoma and skin, lung, prostate, breast, ovarian, liver, gastrointestinal, pancreatic and colorectal epithelial cancers. Curcumin mediates its anti-proliferative, anti-invasive and apoptotic effects on cancer cells, including cancer stem/progenitor cells and their progenies, through multiple molecular mechanisms. The oncogenic pathways inhibited by curcumin encompass the members of epidermal growth factor receptors (EGFR and erbB2, sonic hedgehog (SHH/GLIs and Wnt/β-catenin and downstream signaling elements such as Akt, nuclear factor-kappa B (NF-κB and signal transducers and activators of transcription (STATs. In counterbalance, the high metabolic instability and poor systemic bioavailability of curcumin limit its therapeutic efficacy in human. Of great therapeutic interest, the selective delivery of synthetic analogs or nanotechnology-based formulations of curcumin to tumors, alone or in combination with other anticancer drugs, may improve their chemopreventive and chemotherapeutic efficacies against cancer progression and relapse. Novel curcumin formulations may also be used to reverse drug resistance, eradicate the total cancer cell mass and improve the anticarcinogenic efficacy of the current anti-hormonal and chemotherapeutic treatments for patients with various aggressive and lethal cancers.

  5. Simulation of continuously logical base cells (CL BC) with advanced functions for analog-to-digital converters and image processors (United States)

    Krasilenko, Vladimir G.; Lazarev, Alexander A.; Nikitovich, Diana V.


    The paper considers results of design and modeling of continuously logical base cells (CL BC) based on current mirrors (CM) with functions of preliminary analogue and subsequent analogue-digital processing for creating sensor multichannel analog-to-digital converters (SMC ADCs) and image processors (IP). For such with vector or matrix parallel inputs-outputs IP and SMC ADCs it is needed active basic photosensitive cells with an extended electronic circuit, which are considered in paper. Such basic cells and ADCs based on them have a number of advantages: high speed and reliability, simplicity, small power consumption, high integration level for linear and matrix structures. We show design of the CL BC and ADC of photocurrents and their various possible implementations and its simulations. We consider CL BC for methods of selection and rank preprocessing and linear array of ADCs with conversion to binary codes and Gray codes. In contrast to our previous works here we will dwell more on analogue preprocessing schemes for signals of neighboring cells. Let us show how the introduction of simple nodes based on current mirrors extends the range of functions performed by the image processor. Each channel of the structure consists of several digital-analog cells (DC) on 15-35 CMOS. The amount of DC does not exceed the number of digits of the formed code, and for an iteration type, only one cell of DC, complemented by the device of selection and holding (SHD), is required. One channel of ADC with iteration is based on one DC-(G) and SHD, and it has only 35 CMOS transistors. In such ADCs easily parallel code can be realized and also serial-parallel output code. The circuits and simulation results of their design with OrCAD are shown. The supply voltage of the DC is 1.8÷3.3V, the range of an input photocurrent is 0.1÷24μA, the transformation time is 20÷30nS at 6-8 bit binary or Gray codes. The general power consumption of the ADC with iteration is only 50÷100μW, if the

  6. Are Scientific Analogies Metaphors? (United States)


    and healer Paracelsus , writing within a century of Kepler and Galileo: what, then, is the short and easy way whereby Sol (gold) and Luna (silver) can be...planets again receive a body and life and live as before. Take this body from the life and the earth. Keep it. It is Sol and Luna. 30 Aim ( Paracelsus ...Rutherford analogy, even as known at the time. Instead of using a mutually constraining system of base relationships Paracelsus applies new relations: e.g

  7. Behavior of the guanine base in G-quadruplexes probed by the fluorescent guanine analog, 6-methyl isozanthopterin

    Energy Technology Data Exchange (ETDEWEB)

    Han, Ji Hoon; Chitrapriya, Nataraj; Lee, Hyun Suk; Lee, Young Ae; Kim, Seog K. [Dept. of Chemistry, Yeungnam University, Gyeongsan (Korea, Republic of); Jung, Maeng Joon [Dept. of Chemistry, Kyungpook National University, Daegu (Korea, Republic of)


    In this study, circular dichroism (CD) spectrum and fluorescence techniques were used to examine the dynamic properties and microenvironment of the guanine base (G) at the central loop and at the middle of the G-stem of the G-quadruplex formed from the G{sub 3}T{sub 2}G{sub 3}TGTG{sub 3}T{sub 2}G{sub 3} sequence (G-quadruplex 1), in which the G base at the 10th and 13th position were replaced with a fluorescent G analog, 6-methyl isoxanthopterin (6MI) (G-quadruplex 2 and 3, respectively). For all G-quadruplexes, the CD spectrum revealed a positive band at 263 nm and a shoulder at 298 nm, and the thermal melting profiles were the sum of at least two sigmoidal curves. These observations indicated the presence of two conformers in the G-quadruplex. The fluorescence intensity of G-quadruplex 2 was greater than 3, as expected from the extent of stacking interaction, which is larger in the G(6MI)G sequence than the T(6MI)T sequence. The efficiency of fluorescence quenching by the polar acrylamide quencher and negatively charged I− quencher were larger for G-quadruplex 3, suggesting that 6MI in the G(6MI)G stem is exposed more to the aqueous environment compared to that in the T(6MI)T central loop. In the latter case, 6MI may direct to the center of the top G-quartet layer. The possibility of hydrogen bond formation between the carbonyl group of 6MI and the acrylamide of the G-quadruplex 3 was proposed.

  8. Genome-Wide Mutation Avalanches Induced in Diploid Yeast Cells by a Base Analog or an APOBEC Deaminase (United States)

    Lada, Artem G.; Stepchenkova, Elena I.; Waisertreiger, Irina S. R.; Noskov, Vladimir N.; Dhar, Alok; Eudy, James D.; Boissy, Robert J.; Hirano, Masayuki; Rogozin, Igor B.; Pavlov, Youri I.


    Genetic information should be accurately transmitted from cell to cell; conversely, the adaptation in evolution and disease is fueled by mutations. In the case of cancer development, multiple genetic changes happen in somatic diploid cells. Most classic studies of the molecular mechanisms of mutagenesis have been performed in haploids. We demonstrate that the parameters of the mutation process are different in diploid cell populations. The genomes of drug-resistant mutants induced in yeast diploids by base analog 6-hydroxylaminopurine (HAP) or AID/APOBEC cytosine deaminase PmCDA1 from lamprey carried a stunning load of thousands of unselected mutations. Haploid mutants contained almost an order of magnitude fewer mutations. To explain this, we propose that the distribution of induced mutation rates in the cell population is uneven. The mutants in diploids with coincidental mutations in the two copies of the reporter gene arise from a fraction of cells that are transiently hypersensitive to the mutagenic action of a given mutagen. The progeny of such cells were never recovered in haploids due to the lethality caused by the inactivation of single-copy essential genes in cells with too many induced mutations. In diploid cells, the progeny of hypersensitive cells survived, but their genomes were saturated by heterozygous mutations. The reason for the hypermutability of cells could be transient faults of the mutation prevention pathways, like sanitization of nucleotide pools for HAP or an elevated expression of the PmCDA1 gene or the temporary inability of the destruction of the deaminase. The hypothesis on spikes of mutability may explain the sudden acquisition of multiple mutational changes during evolution and carcinogenesis. PMID:24039593

  9. The use of UV, FT-IR and Raman spectra for the identification of the newest penem analogs: solutions based on mathematic procedure and the density functional theory. (United States)

    Cielecka-Piontek, J; Lewandowska, K; Barszcz, B; Paczkowska, M


    The application of ultraviolet, FT-IR and Raman spectra was proposed for identification studies of the newest penem analogs (doripenem, biapenem and faropenem). An identification of the newest penem analogs based on their separation from related substances was achieved after the application of first derivative of direct spectra in ultraviolet which permitted elimination of overlapping effects. A combination of experimental and theoretical studies was performed for analyzing the structure and vibrational spectra (FT-IR and Raman spectra) of doripenem, biapenem and faropenem. The calculations were conducted using the density functional theory with the B3LYP hybrid functional and 6-31G(d,p) basis set. The confirmation of the applicability of the DFT methodology for interpretation of vibrational IR and Raman spectra of the newest penem analogs contributed to determination of changes of vibrations in the area of the most labile bonds. By employing the theoretical approach it was possible to eliminate necessity of using reference standards which - considering the instability of penem analogs - require that correction coefficients are factored in. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Science Teachers' Analogical Reasoning (United States)

    Mozzer, Nilmara Braga; Justi, Rosária


    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to introduce analogies in their lessons. Both aspects have been discussed in the literature in the last few decades. However, almost nothing is known about how teachers draw their own analogies for instructional purposes or, in other words, about how they reason analogically when planning and conducting teaching. This is the focus of this paper. Six secondary teachers were individually interviewed; the aim was to characterize how they perform each of the analogical reasoning subprocesses, as well as to identify their views on analogies and their use in science teaching. The results were analyzed by considering elements of both theories about analogical reasoning: the structural mapping proposed by Gentner and the analogical mechanism described by Vosniadou. A comprehensive discussion of our results makes it evident that teachers' content knowledge on scientific topics and on analogies as well as their pedagogical content knowledge on the use of analogies influence all their analogical reasoning subprocesses. Our results also point to the need for improving teachers' knowledge about analogies and their ability to perform analogical reasoning.

  11. Antarctic analogs for Enceladus (United States)

    Murray, A. E.; Andersen, D. T.; McKay, C. P.


    Enceladus is a new world for Astrobiology. The Cassini discovery of the icy plume emanating from the South Polar region indicates an active world, where detection of water, organics, sodium, and nano-particle silica in the plume strongly suggests that the source is a subsurface salty ocean reservoir. Recent gravity data from Cassini confirms the presence of a regional sea extending north to 50°S. An ocean habitat under a thick ice cover is perhaps a recurring theme in the Outer Solar System, but what makes Enceladus unique is that the plume jetting out into space is carrying samples of this ocean. Therefore, through the study of Enceladus' plumes we can gain new insights not only of a possible habitable world in the Solar Systems, but also about the formation and evolution of other icy-satellites. Cassini has been able to fly through this plume - effectively sampling the ocean. It is time to plan for future missions that do more detailed analyses, possibly return samples back to Earth and search for evidence of life. To help prepare for such missions, the need for earth-based analog environments is essential for logistical, methodological (life detection) and theoretical development. We have undertaken studies of two terrestrial environments that are close analogs to Enceladus' ocean: Lake Vida and Lake Untersee - two ice-sealed Antarctic lakes that represent physical, chemical and possibly biological analogs for Enceladus. By studying the diverse biology and physical and chemical constraints to life in these two unique lakes we will begin to understand the potential habitability of Enceladus and other icy moons, including possible sources of nutrients and energy, which together with liquid water are the key ingredients for life. Analog research such as this will also enable us to develop and test new strategies to search for evidence of life on Enceladus.

  12. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc


    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

  13. Analogical proportions: another logical view (United States)

    Prade, Henri; Richard, Gilles

    This paper investigates the logical formalization of a restricted form of analogical reasoning based on analogical proportions, i.e. statements of the form a is to b as c is to d. Starting from a naive set theoretic interpretation, we highlight the existence of two noticeable companion proportions: one states that a is to b the converse of what c is to d (reverse analogy), while the other called paralogical proportion expresses that what a and b have in common, c and d have it also. We identify the characteristic postulates of the three types of proportions and examine their consequences from an abstract viewpoint. We further study the properties of the set theoretic interpretation and of the Boolean logic interpretation, and we provide another light on the understanding of the role of permutations in the modeling of the three types of proportions. Finally, we address the use of these proportions as a basis for inference in a propositional setting, and relate it to more general schemes of analogical reasoning. The differences between analogy, reverse-analogy, and paralogy is still emphasized in a three-valued setting, which is also briefly presented.

  14. Analogy: Justification for Logic. (United States)

    Sacksteder, William


    Presents and defends the thesis that it is analogy which provides justification for any logic, and for any argument to the extent that it depends on logic for justification. Analogy acquires inept support from logic, but logic acquires adroit support from analogy. (JMF)

  15. Producing and Recognizing Analogical Relations (United States)

    Lipkens, Regina; Hayes, Steven C


    Analogical reasoning is an important component of intelligent behavior, and a key test of any approach to human language and cognition. Only a limited amount of empirical work has been conducted from a behavior analytic point of view, most of that within Relational Frame Theory (RFT), which views analogy as a matter of deriving relations among relations. The present series of four studies expands previous work by exploring the applicability of this model of analogy to topography-based rather than merely selection-based responses and by extending the work into additional relations, including nonsymmetrical ones. In each of the four studies participants pretrained in contextual control over nonarbitrary stimulus relations of sameness and opposition, or of sameness, smaller than, and larger than, learned arbitrary stimulus relations in the presence of these relational cues and derived analogies involving directly trained relations and derived relations of mutual and combinatorial entailment, measured using a variety of productive and selection-based measures. In Experiment 1 participants successfully recognized analogies among stimulus networks containing same and opposite relations; in Experiment 2 analogy was successfully used to extend derived relations to pairs of novel stimuli; in Experiment 3 the procedure used in Experiment 1 was extended to nonsymmetrical comparative relations; in Experiment 4 the procedure used in Experiment 2 was extended to nonsymmetrical comparative relations. Although not every participant showed the effects predicted, overall the procedures occasioned relational responses consistent with an RFT account that have not yet been demonstrated in a behavior-analytic laboratory setting, including productive responding on the basis of analogies. PMID:19230515

  16. Comparative acid-base properties of the surface of components of the CdTe-ZnS system in series of substitutional solid solutions and their analogs (United States)

    Kirovskaya, I. A.; Kasatova, I. Yu.


    The acid-base properties of the surface of solid solutions and binary components of the CdTe-ZnS system are studied by hydrolytic adsorption, nonaqueous conductometric titration, mechanochemistry, IR spectroscopy, and Raman scattering spectroscopy. The strength, nature, and concentration of acid centers on the original surface and that exposed to CO are determined. The changes in acid-base properties in dependence on the composition of the system under investigation in the series of CdB6, ZnB6 analogs are studied.

  17. [Acid-base, tautomeric and isomeric equilibrium of pyridoxal oximes, pyridoxal-5'-phosphate and some of their analogs]. (United States)

    Bokovoĭ, V A; Bazhulina, N P; Morozov, Iu V; Chekhov, V O


    Success has been achieved in detailed understanding of tautomeric and isomeric equilibria and search for the new tautomeric and isomeric forms of oximes of pyridoxal, pyridoxal-5'-phosphate and some of their analogs, their presence is explained. This is due to a careful deconvolution of absorption spectra of different ionic forms of oximes into bands corresponding to separate electronic transitions. The spectroscopical data and the results of quantum-chemical calculations are compared for all the forms of compounds under investigation. As it has been found to be valid for other vitamin B6 derivatives as well, quantum-chemical calculations can be used for analytical purposes.

  18. Analog and hybrid computing

    CERN Document Server

    Hyndman, D E


    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

  19. Efficiency and hardware comparison of analog control-based and digital control-based 70 W two-stage power factor corrector and DC-DC converters

    DEFF Research Database (Denmark)

    Török, Lajos; Munk-Nielsen, Stig


    A comparison of an analog and a digital controller driven 70 W two-stage power factor corrector converter is presented. Both controllers are operated in average current-mode-control for the PFC and peak current control for the DC-DC converter. Digital controller design and converter modeling...... is described. Results show that digital control can compete with the analog one in efficiency, PFC and THD....

  20. Environmental Temperature Effect on the Far-Infrared Absorption Features of Aromatic-Based Titan's Aerosol Analogs (United States)

    Gautier, Thomas; Trainer, Melissa G.; Loeffler, Mark J.; Sebree, Joshua A.; Anderson, Carrie M.


    Benzene detection has been reported in Titans atmosphere both in the stratosphere at ppb levels by remote sensing and in the thermosphere at ppm levels by the Cassini's Ion and Neutral Mass Spectrometer. This detection supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titans atmospheric chemistry, especially in the formation of aerosols. Indeed, aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation. It has been shown recently that aerosol analogs produced from a gas mixture containing a low concentration of aromatic and/or heteroaromatic molecules (benzene, naphthalene, pyridine, quinoline and isoquinoline) have spectral signatures below 500/cm, a first step towards reproducing the aerosol spectral features observed by Cassini's Composite InfraRed Spectrometer (CIRS) in the far infrared. In this work we investigate the influence of environmental temperature on the absorption spectra of such aerosol samples, simulating the temperature range to which aerosols, once formed, are exposed during their transport through Titans stratosphere. Our results show that environmental temperature does not have any major effect on the spectral shape of these aerosol analogs in the far-infrared, which is consistent with the CIRS observations.

  1. Study of the National Science Foundation's South Pole Station as an analogous data base for the logistical support of a Moon laboratory (United States)

    Hickam, H. H., Jr.


    The day will come when the United States will want to return to the Earth's Moon. When that occurs, NASA may look to the Apollo program for technical and inspirational guidance. The Apollo program, however, was designed to be an end to itself--the landing of a man on the Moon and his return safely within the decade of the 1960's. When that was accomplished, the program folded because it was not self-sustaining. The next time we return to the Moon, we should base our planning on a program that is designed to be a sustained effort for an indefinite period. It is the thrust of this report that the South Pole Station of the National Science Foundation can be used to develop analogs for the construction, funding, and logistical support of a lunar base. Other analogs include transportation and national efforts versus international cooperation. A recommended lunar base using the South Pole Station as inspiration is provided, as well as details concerning economical construction of the base over a 22-year period.

  2. Communication channels analogous to one out of two oblivious transfers based on quantum uncertainty. II. Closing EPR-type loopholes

    International Nuclear Information System (INIS)

    Shimizu, Kaoru; Imoto, Nobuyuki


    In a recent proposal for a quantum cryptographic scheme analogous to one out of two oblivious transfers [Phys. Rev. A 66, 052316 (2002)], a sender, Bob, can encode two bits of information (X,Y) in a quantum carrier but a receiver, Alice, can decode only either X or Y dependent on her choice. Although Bob can discover her choice whenever he desires, she can detect this with a 50% probability. This paper clarifies the amount of information that Bob can expect to obtain from Alice without being detected by her by means of an Einstein-Podolsky-Rosen (EPR) type of attack. We can show that Bob inevitably fails to discover her choice with a 50% probability even though he can always completely escape her detection

  3. Using analog instruments in Tracker video-based experiments to understand the phenomena of electricity and magnetism in physics education (United States)

    Aguilar-Marín, Pablo; Chavez-Bacilio, Mario; Jáuregui-Rosas, Segundo


    Tracker is a piece of freeware software, designed to use video recorded images of the motion of objects as input data, and has been mostly applied in physics education to analyse and simulate physical phenomena in mechanics. In this work we report the application of Tracker to the study of experiments in electricity and magnetism using analog instruments for electrical signal measurements. As we are unable to directly video-track the motion of electrons in electric circuits, the angular deflections of the instruments’ pointers were video captured instead. The kinematic variables (angular position as a function of time) had to be related to the electrical ones (voltages and currents as a function of time). Two well-known experiments in physics teaching, the RC circuit for charging and discharging a capacitor and Faraday electromagnetic induction, were chosen to illustrate the procedures. The third experiment analysed and modeled with Tracker was the rather well-known electromagnetic retardation of disk- or cylinder-shaped magnets falling inside non-magnetic metallic pipes. Instead of metallic pipes we used an aluminum plate with an arrangement of a couple of parallelepiped-shaped magnets falling parallel to the plate. In the three cases studied, the experimental and the Tracker simulation results were in very good agreement. These outcomes show that it is possible to exploit the potential of Tracker software in areas other than mechanics, in areas where electrical signals are involved. The experiments are inexpensive and simple to perform, and are suitable for high school and introductory undergraduate courses in electricity, magnetism and electronics. We propose the use of Tracker combined with analog measuring devices to explore further its applications in electricity, magnetism, electronics and in other experimental sciences where electrical signals are involved.

  4. Influence of phosphoproteins' biomimetic analogs on remineralization of mineral-depleted resin-dentin interfaces created with ion-releasing resin-based systems. (United States)

    Sauro, Salvatore; Osorio, Raquel; Watson, Timothy F; Toledano, Manuel


    The study aimed at evaluating the remineralization of acid-etched dentin pre-treated with primers containing biomimetic analogs and bonded using an ion-releasing light-curable resin-based material. An experimental etch-and-rinse adhesive system filled with Ca(2+), PO4(3-)-releasing Ca-Silicate micro-fillers was created along with two experimental primers containing biomimetic analogs such as sodium trimetaphosphate (TMP) and/or polyaspartic acid (PLA). Dentin specimens etched with 37% H3PO4 were pre-treated with two different aqueous primers containing the polyanionic biomimetic analogs or deionized water and subsequently bonded using the experimental resin-based materials. The specimens were sectioned and analyzed by AFM/nanoindentation to evaluate changes in the modulus of elasticity (Ei) across the resin-dentin interface at different AS storage periods (up to 90 days). Raman cluster analysis was also performed to evaluate the chemical changes along the interface. The phosphate uptake by the acid-etched dentin was evaluated using the ATR-FTIR. Additional resin-dentin specimens were tested for microtensile bond strength. SEM examination was performed after de-bonding, while confocal laser microscopy was used to evaluate the interfaces ultramorphology and micropermeability. Both biomimetic primers induced phosphate uptake by acid-etched dentin. Specimens created with the ion-releasing resin in combination with the pre-treatment primers containing either PLA and TMA showed the greatest recovery of the Ei of the hybrid layer, with no decrease in μTBS (p>0.05) after 3-month AS storage. The ion-releasing resin applied after use of the biomimetic primers showed the greatest reduction in micropermeability due to mineral precipitation; these results were confirmed using SEM. The use of the ion-releasing resin-based system applied to acid-etched dentin pre-treated with biomimetic primers containing analogs of phosphoproteins such as poly-l-aspartic acid and/or sodium

  5. Fast multichannel analog storage system

    International Nuclear Information System (INIS)

    Freytag, D.R.


    A Multichannel Analog Storage System based on a commercial 32-channel parallel in/serial out (PISO) analog shift register is described. The basic unit is a single width CAMAC module containing 512 analog cells and the associated logic for data storage and subsequent readout. At sampling rates of up to 30 MHz the signals are strobed directly into the PISO. At higher rates signals are strobed into a fast presampling stage and subsequently transferred in block form into an array of PISO's. Sampling rates of 300 MHz have been achieved with the present device and 1000 MHz are possible with improved signal drivers. The system is well suited for simultaneous handling of many signal channels with moderate numbers of samples in each channel. RMS noise over full scale signal has been measured as 1:3000 (approx. = 11 bit). However, nonlinearities in the response and differences in sensitivity of the analog cells require an elaborate calibration system in order to realize 11 bit accuracy for the analog information

  6. Analog circuit design

    CERN Document Server

    Dobkin, Bob


    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. <

  7. Efficiency and hardware comparison of analog control-based and digital control-based 70 W two-stage power factor corrector and DC-DC converters

    DEFF Research Database (Denmark)

    Török, Lajos; Munk-Nielsen, Stig


    A comparison of an analog and a digital controller driven 70 W two-stage power factor corrector converter is presented. Both controllers are operated in average current-mode-control for the PFC and peak current control for the DC-DC converter. Digital controller design and converter modeling is d...... is described. Results show that digital control can compete with the analog one in efficiency, PFC and THD.......A comparison of an analog and a digital controller driven 70 W two-stage power factor corrector converter is presented. Both controllers are operated in average current-mode-control for the PFC and peak current control for the DC-DC converter. Digital controller design and converter modeling...

  8. From analog to digital

    CERN Document Server

    Belleman, J


    Analog-to-digital conversion and its reverse, digital-to-analog conversion, are ubiquitous in all modern electronics, from instrumentation and telecommunication equipment to computers and entertainment. We shall explore the consequences of converting signals between the analog and digital domains and give an overview of the internal architecture and operation of a number of converter types. The importance of analog input and clock signal integrity will be explained and methods to prevent or mitigate the effects of interference will be shown. Examples will be drawn from several manufacturers' datasheets.

  9. Priming analogical reasoning with false memories. (United States)

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


    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.

  10. Neural correlates of creativity in analogical reasoning. (United States)

    Green, Adam E; Kraemer, David J M; Fugelsang, Jonathan A; Gray, Jeremy R; Dunbar, Kevin N


    Brain-based evidence has implicated the frontal pole of the brain as important for analogical mapping. Separately, cognitive research has identified semantic distance as a key determinant of the creativity of analogical mapping (i.e., more distant analogies are generally more creative). Here, we used functional magnetic resonance imaging to assess brain activity during an analogy generation task in which we varied the semantic distance of analogical mapping (as derived quantitatively from a latent semantic analysis). Data indicated that activity within an a priori region of interest in left frontopolar cortex covaried parametrically with increasing semantic distance, even after removing effects of task difficulty. Results implicate increased recruitment of frontopolar cortex as a mechanism for integrating semantically distant information to generate solutions in creative analogical reasoning. 2012 APA, all rights reserved

  11. A Power Conditioning Stage Based on Analog-Circuit MPPT Control and a Superbuck Converter for Thermoelectric Generators in Spacecraft Power Systems (United States)

    Sun, Kai; Wu, Hongfei; Cai, Yan; Xing, Yan


    A thermoelectric generator (TEG) is a very important kind of power supply for spacecraft, especially for deep-space missions, due to its long lifetime and high reliability. To develop a practical TEG power supply for spacecraft, a power conditioning stage is indispensable, being employed to convert the varying output voltage of the TEG modules to a definite voltage for feeding batteries or loads. To enhance the system reliability, a power conditioning stage based on analog-circuit maximum-power-point tracking (MPPT) control and a superbuck converter is proposed in this paper. The input of this power conditioning stage is connected to the output of the TEG modules, and the output of this stage is connected to the battery and loads. The superbuck converter is employed as the main circuit, featuring low input current ripples and high conversion efficiency. Since for spacecraft power systems reliable operation is the key target for control circuits, a reset-set flip-flop-based analog circuit is used as the basic control circuit to implement MPPT, being much simpler than digital control circuits and offering higher reliability. Experiments have verified the feasibility and effectiveness of the proposed power conditioning stage. The results show the advantages of the proposed stage, such as maximum utilization of TEG power, small input ripples, and good stability.

  12. Analog computing for a new nuclear reactor dynamic model based on a time-dependent second order form of the neutron transport equation

    International Nuclear Information System (INIS)

    Pirouzmand, Ahmad; Hadad, Kamal; Suh, Kune Y.


    This paper considers the concept of analog computing based on a cellular neural network (CNN) paradigm to simulate nuclear reactor dynamics using a time-dependent second order form of the neutron transport equation. Instead of solving nuclear reactor dynamic equations numerically, which is time-consuming and suffers from such weaknesses as vulnerability to transient phenomena, accumulation of round-off errors and floating-point overflows, use is made of a new method based on a cellular neural network. The state-of-the-art shows the CNN as being an alternative solution to the conventional numerical computation method. Indeed CNN is an analog computing paradigm that performs ultra-fast calculations and provides accurate results. In this study use is made of the CNN model to simulate the space-time response of scalar flux distribution in steady state and transient conditions. The CNN model also is used to simulate step perturbation in the core. The accuracy and capability of the CNN model are examined in 2D Cartesian geometry for two fixed source problems, a mini-BWR assembly, and a TWIGL Seed/Blanket problem. We also use the CNN model concurrently for a typical small PWR assembly to simulate the effect of temperature feedback, poisons, and control rods on the scalar flux distribution

  13. A mechanism-based 3D-QSAR approach for classification and prediction of acetylcholinesterase inhibitory potency of organophosphate and carbamate analogs (United States)

    Lee, Sehan; Barron, Mace G.


    Organophosphate (OP) and carbamate esters can inhibit acetylcholinesterase (AChE) by binding covalently to a serine residue in the enzyme active site, and their inhibitory potency depends largely on affinity for the enzyme and the reactivity of the ester. Despite this understanding, there has been no mechanism-based in silico approach for classification and prediction of the inhibitory potency of ether OPs or carbamates. This prompted us to develop a three dimensional prediction framework for OPs, carbamates, and their analogs. Inhibitory structures of a compound that can form the covalent bond were identified through analysis of docked conformations of the compound and its metabolites. Inhibitory potencies of the selected structures were then predicted using a previously developed three dimensional quantitative structure-active relationship. This approach was validated with a large number of structurally diverse OP and carbamate compounds encompassing widely used insecticides and structural analogs including OP flame retardants and thio- and dithiocarbamate pesticides. The modeling revealed that: (1) in addition to classical OP metabolic activation, the toxicity of carbamate compounds can be dependent on biotransformation, (2) OP and carbamate analogs such as OP flame retardants and thiocarbamate herbicides can act as AChEI, (3) hydrogen bonds at the oxyanion hole is critical for AChE inhibition through the covalent bond, and (4) π-π interaction with Trp86 is necessary for strong inhibition of AChE. Our combined computation approach provided detailed understanding of the mechanism of action of OP and carbamate compounds and may be useful for screening a diversity of chemical structures for AChE inhibitory potency.

  14. Comprehensive analysis of sub-20 nm black phosphorus based junctionless-recessed channel MOSFET for analog/RF applications (United States)

    Kumar, Ajay; Tripathi, M. M.; Chaujar, Rishu


    In this work, a comprehensive analog and RF performance of a novel Black Phosphorus-Junctionless-Recessed Channel (BP-JL-RC) MOSFET has been explored at 45 nm technology node (Gate length = 20 nm). The integration of black phosphorus with junctionless recessed channel MOSFET, leads to higher drain current of about 0.3 mA and excellent switching ratio (of the order of 1011) due to reduced off-current which leads to improvement in sub-threshold slope (SS) (67mV/dec). Further, RF performance metrics have also been studied with an aim to analyze high-frequency performance. The following FOMs have been evaluated: cut-off frequency (fT), maximum oscillator frequency (fMAX), stern stability factor, various power gains and parasitic capacitances at THz frequency range. Thus, in addition to the high packing density offered by RC MOSFET, the proposed design finds numerous application at THz frequency making it a promising candidate at wafer scale integration level.

  15. Referencing techniques for high-speed confocal fluorescence lifetime imaging microscopy (FLIM) based on analog mean-delay (AMD) method (United States)

    Kim, Byungyeon; Lee, Minsuk; Park, Byungjun; Lee, Seungrag; Won, Youngjae


    Analog mean-delay (AMD) method is a new powerful alternative method in determining the lifetime of a fluorescence molecule for high-speed confocal fluorescence lifetime imaging microscopy (FLIM). Even though the photon economy and the lifetime precision of the AMD method are proven to be as good as the state-of-the-art time-correlated single photon counting (TC-SPC) method, there have been some speculations and concerns about the accuracy of this method. In the AMD method, the temporal waveform of an emitted fluorescence signal is directly recorded with a slow digitizer whose bandwidth is much lower than the temporal resolution of lifetime to be measured. We found that the drifts and the fluctuations of the absolute zero position in a measured temporal waveform are the major problems in the AMD method. As a referencing technique, we already proposed dual-channel waveform measurement scheme that may suppress these errors. In this study, we have demonstrated real-time confocal AMD-FLIM system with dual-channel waveform measurement technique.

  16. Mineral formation on metallic copper in a `Future repository site environment`: Textural considerations based on natural analogs

    Energy Technology Data Exchange (ETDEWEB)

    Amcoff, Oe. [Uppsala Univ. (Sweden). Inst. of Earth Sciences


    Copper mineral formation in the Swedish `repository site environment` is discussed. Special attention is given to ore mineral textures (=the spatial relation among minerals), with examples given from nature. It is concluded: By analogy with observations from natural occurrences, an initial coating of Cu-oxide on the canister surface (because of entrapped air during construction) will probably not hinder a later sulphidation process. Early formation of Cu-sulphides on the canister surface may be accompanied by formation of CuFe-sulphides. The latter phase(s) may form through replacement of the Cu-sulphides or, alternatively, by means of reaction between dissolved copper and fine-grained iron sulphide (pyrite) in the surrounding bentonite. Should for some reason the bentonite barrier fail and the conditions become strongly oxidizing, we can expect crustifications and rhythmic growths of Cu(II)-phases, like malachite (Cu{sub 2}(OH){sub 2}CO{sub 3}). A presence of Fe{sup 2} in the clay minerals making up the bentonite might prove to have an adverse effect on the canister stability, since, in this case, the bentonite might be expected to act as a sink for dissolved copper. The mode of mineral growth along the copper - bentonite interface remains an open question.

  17. Analog pulse processor (United States)

    Wessendorf, Kurt O.; Kemper, Dale A.


    A very low power analog pulse processing system implemented as an ASIC useful for processing signals from radiation detectors, among other things. The system incorporates the functions of a charge sensitive amplifier, a shaping amplifier, a peak sample and hold circuit, and, optionally, an analog to digital converter and associated drivers.

  18. Hydraulic Capacitor Analogy (United States)

    Baser, Mustafa


    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…

  19. Challenges in Using Analogies (United States)

    Lin, Shih-Yin; Singh, Chandralekha


    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…

  20. A Simplified Top-Oil Temperature Model for Transformers Based on the Pathway of Energy Transfer Concept and the Thermal-Electrical Analogy

    Directory of Open Access Journals (Sweden)

    Muhammad Hakirin Roslan


    Full Text Available This paper presents an alternative approach to determine the simplified top-oil temperature (TOT based on the pathway of energy transfer and thermal-electrical analogy concepts. The main contribution of this study is the redefinition of the nonlinear thermal resistance based on these concepts. An alternative approximation of convection coefficient, h, based on heat transfer theory was proposed which eliminated the requirement of viscosity. In addition, the lumped capacitance method was applied to the thermal-electrical analogy to derive the TOT thermal equivalent equation in differential form. The TOT thermal model was evaluated based on the measured TOT of seven transformers with either oil natural air natural (ONAN or oil natural air forced (ONAF cooling modes obtained from temperature rise tests. In addition, the performance of the TOT thermal model was tested on step-loading of a transformer with an ONAF cooling mode obtained from previous studies. A comparison between the TOT thermal model and the existing TOT Thermal-Electrical, Exponential (IEC 60076-7, and Clause 7 (IEEE C57.91-1995 models was also carried out. It was found that the measured TOT of seven transformers are well represented by the TOT thermal model where the highest maximum and root mean square (RMS errors are 6.66 °C and 2.76 °C, respectively. Based on the maximum and RMS errors, the TOT thermal model performs better than Exponential and Clause 7 models and it is comparable with the Thermal-Electrical 1 (TE1 and Thermal-Electrical 2 (TE2 models. The same pattern is found for the TOT thermal model under step-loading where the maximum and RMS errors are 5.77 °C and 2.02 °C.

  1. Optical analogy. Synthesis report

    International Nuclear Information System (INIS)


    The authors report the study of conditions under which light attenuation (reflection, diffusion, absorption) and the attenuation of some radiations (notably thermal neutrons) can be described with analogical calculations. The analogy between light physical properties and neutron properties is not searched for, but the analogy between their attenuation characteristics. After having discussed this possible analogy, they propose a mathematical formulation of neutron and optical phenomena which could theoretically justify the optical analogy. The second part reports a more practical study of optics problems such as the study of simple optics materials and illumination measurements, or more precisely the study of angular distributions of optical reflections, a determination of such angular distributions, and an experimental determination of the albedo

  2. Estimation of channel mismatches in time-interleaved analog-to-digital converters based on fractional delay and sine curve fitting. (United States)

    Guo, Lianping; Tian, Shulin; Jiang, Jun


    This paper proposes an algorithm to estimate the channel mismatches in time-interleaved analog-to-digital converter (TIADC) based on fractional delay (FD) and sine curve fitting. Choose one channel as the reference channel and apply FD to the output samples of reference channel to obtain the ideal samples of non-reference channels with no mismatches. Based on least square method, the sine curves are adopted to fit the ideal and the actual samples of non-reference channels, and then the mismatch parameters can be estimated by comparing the ideal sine curves and the actual ones. The principle of this algorithm is simple and easily understood. Moreover, its implementation needs no extra circuits, lowering the hardware cost. Simulation results show that the estimation accuracy of this algorithm can be controlled within 2%. Finally, the practicability of this algorithm is verified by the measurement results of channel mismatch errors of a two-channel TIADC prototype.

  3. A homogeneous fluorometric assay platform based on novel synthetic proteins

    International Nuclear Information System (INIS)

    Vardar-Schara, Goenuel; Krab, Ivo M.; Yi, Guohua; Su, Wei Wen


    Novel synthetic recombinant sensor proteins have been created to detect analytes in solution, in a rapid single-step 'mix and read' noncompetitive homogeneous assay process, based on modulating the Foerster resonance energy transfer (FRET) property of the sensor proteins upon binding to their targets. The sensor proteins comprise a protein scaffold that incorporates a specific target-capturing element, sandwiched by genetic fusion between two molecules that form a FRET pair. The utility of the sensor proteins was demonstrated via three examples, for detecting an anti-biotin Fab antibody, a His-tagged recombinant protein, and an anti-FLAG peptide antibody, respectively, all done directly in solution. The diversity of sensor-target interactions that we have demonstrated in this study points to a potentially universal applicability of the biosensing concept. The possibilities for integrating a variety of target-capturing elements with a common sensor scaffold predict a broad range of practical applications

  4. Satellite-Based Thermophysical Analysis of Volcaniclastic Deposits: A Terrestrial Analog for Mantled Lava Flows on Mars

    Directory of Open Access Journals (Sweden)

    Mark A. Price


    Full Text Available Orbital thermal infrared (TIR remote sensing is an important tool for characterizing geologic surfaces on Earth and Mars. However, deposition of material from volcanic or eolian activity results in bedrock surfaces becoming significantly mantled over time, hindering the accuracy of TIR compositional analysis. Moreover, interplay between particle size, albedo, composition and surface roughness add complexity to these interpretations. Apparent Thermal Inertia (ATI is the measure of the resistance to temperature change and has been used to determine parameters such as grain/block size, density/mantling, and the presence of subsurface soil moisture/ice. Our objective is to document the quantitative relationship between ATI derived from orbital visible/near infrared (VNIR and thermal infrared (TIR data and tephra fall mantling of the Mono Craters and Domes (MCD in California, which were chosen as an analog for partially mantled flows observed at Arsia Mons volcano on Mars. The ATI data were created from two images collected ~12 h apart by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER instrument. The results were validated with a quantitative framework developed using fieldwork that was conducted at 13 pre-chosen sites. These sites ranged in grain size from ash-sized to meter-scale blocks and were all rhyolitic in composition. Block size and mantling were directly correlated with ATI. Areas with ATI under 2.3 × 10−2 were well-mantled with average grain size below 4 cm; whereas values greater than 3.0 × 10−2 corresponded to mantle-free surfaces. Correlation was less accurate where checkerboard-style mixing between mantled and non-mantled surfaces occurred below the pixel scale as well as in locations where strong shadowing occurred. However, the results validate that the approach is viable for a large majority of mantled surfaces on Earth and Mars. This is relevant for determining the volcanic history of Mars, for

  5. Investigation of Higher Brain Functions in Music Composition Using Models of the Cortex Based on Physical System Analogies. (United States)

    Leng, Xiaodan

    The trion model was developed using the Mountcastle organizational principle for the column as the basic neuronal network in the cortex and the physical system analogy of Fisher's ANNNI spin model. An essential feature is that it is highly structured in time and in spatial connections. Simulations of a network of trions have shown that large numbers of quasi-stable, periodic spatial-temporal firing patterns can be excited. Characteristics of these patterns include the quality of being readily enhanced by only a small change in connection strengths, and that the patterns evolve in certain natural sequences from one to another. With only somewhat different parameters than used for studying memory and pattern recognition, much more flowing and intriguing patterns emerged from the simulations. The results were striking when these probabilistic evolutions were mapped onto pitches and instruments to produce music: For example different simple mappings of the same evolution give music having the "flavor" of a minuet, a waltz, folk music, or styles of specific periods. A theme can be learned so that evolutions have this theme and its variations reoccurring more often. That the trion model is a viable model for the coding of musical structure in human composition and perception is suggested. It is further proposed that model is relevant for examining creativity in the higher cognitive functions of mathematics and chess, which are similar to music. An even higher level of cortical organization was modeled by coupling together several trion networks. Further, one of the crucial features of higher brain function, especially in music composition or appreciation, is the role of emotion and mood as controlled by the many neuromodulators or neuropeptides. The MILA model whose underlying basis is zero-level representation of Kac-Moody algebra is used to modulate periodically the firing threshold of each network. Our preliminary results show that the introduction of "neuromodulation

  6. Computational approaches to analogical reasoning current trends

    CERN Document Server

    Richard, Gilles


    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...

  7. Troubleshooting analog circuits

    CERN Document Server

    Pease, Robert A


    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

  8. Analog multivariate counting analyzers

    CERN Document Server

    Nikitin, A V; Armstrong, T P


    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...

  9. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian


    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. FGF growth factor analogs

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  11. Electrical Circuits and Water Analogies (United States)

    Smith, Frederick A.; Wilson, Jerry D.


    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)

  12. Novel acyclonucleoside analog bearing a 1,2,4-triazole–Schiff base: Synthesis, characterization and analytical studies using square wave-adsorptive stripping voltammetry and HPLC

    Directory of Open Access Journals (Sweden)

    Ali F. Alghamdi


    Full Text Available New acyclonucleoside analogs tethered by a 1,2,4-triazole scaffold were synthesized through the condensation of 4-amino-5-(2-phenyleth-1-yl-2,4-dihydro-3H-1,2,4-triazole-3-thione (2 with benzaldehyde followed by the alkylation of the resulting Schiff base (3with 2-bromoethanol, 3-chloropropanol and/or 3-chloropropan-1,2-diol. Voltammetric studies were carried out for the analysis of 1 × 10−6 mol L−1 of the newly synthesized acyclonucleoside analogs (4–6 using square wave-adsorptive stripping voltammetry (SW-AdSV. The sharp voltammetric peak and high reduction current were recorded using a Britton–Robinson B–R pH 10 buffer at Ep = −1250 mV on the hanging mercury drop surface (HMDE and Ag/AgCl reference electrode. Several experimental conditions were studied, such as the supporting electrolytes, the pH, and the accumulation time, as well as the potential, the scan rate, the frequency and the step potential for 4-benzylideneamino-5-(2-phenyleth-1-yl-3-[(2,3-dihydroxyprop-1-ylthio]-1,2,4-triazole (6. The analytical performance of the voltammetric technique was investigated through the analysis of the calibration curve, the detection limit, the recovery and the stability. The voltammetric analytical applications were evaluated by the recovery of compound (6 in the urine and plasma samples. The HPLC technique was also applied for the separation of compound (6 from interference using a C-18 (5 μm column with UV detection at 254 nm.

  13. Two-zone SiGe base heterojunction bipolar charge plasma transistor for next generation analog and RF applications (United States)

    Bramhane, Lokesh Kumar; Singh, Jawar


    For next generation terahertz applications, heterojunction bipolar transistor (HBT) with reduced dimensions and charge plasma (CP) can be a potential candidate due to simplified and inexpensive process. In this paper, a symmetric lateral two-zone SiGe base heterojunction bipolar charge plasma transistor (HBCPT) with an extruded (extended) base is proposed and its performance at circuit level is studied. The linearly graded electric field in the proposed HBCPT provides improved self gain (β) and cut-off frequency (fT). Two-dimensional (2-D) TCAD and small-signal model based simulations of the proposed HBCPT demonstrates high self gain β 35-172.93 and fT of 1-4 THz for different device parameters. Moreover, fT of 1104.9 GHz and β of 35 can be achieved by decreasing Nb up to 8.2 ×1017cm-3 . Although, fT of 2 THz and 4 THz can also be achieved by reducing the base resistance up to 10 Ω and increasing the emitter/collector length up to 63 nm, respectively. The small-signal analysis of common-emitter amplifier based on the proposed HBCPT demonstrate high voltage gain of 50.11 as compared to conventional HBT (18.1).

  14. Structural determinants of the catalytic inhibition of human topoisomerase IIα by salicylate analogs and salicylate-based drugs. (United States)

    Bau, Jason T; Kurz, Ebba U


    We previously identified salicylate as a novel catalytic inhibitor of human DNA topoisomerase II (topo II; EC that preferentially targets the alpha isoform by interfering with topo II-mediated DNA cleavage. Many pharmaceuticals and compounds found in foods are salicylate-based. We have now investigated whether these are also catalytic inhibitors of topo II and the structural determinants modulating these effects. We have determined that a number of hydroxylated benzoic acids attenuate doxorubicin-induced DNA damage signaling mediated by the ATM protein kinase and inhibit topo II decatenation activity in vitro with varying potencies. Based on the chemical structures of these and other derivatives, we identified unique properties influencing topo II inhibition, including the importance of substitutions at the 2'- and 5'-positions. We extended our findings to a number of salicylate-based pharmaceuticals including sulfasalazine and diflunisal and found that both were effective at attenuating doxorubicin-induced DNA damage signaling, topo II DNA decatenation and they blocked stabilization of doxorubicin-induced topo II cleavable complexes in cells. In a manner similar to salicylate, we determined that these agents inhibit topo II-mediated DNA cleavage. This was accompanied by a concomitant decrease in topo II-mediated ATP-hydrolysis. Taken together, these findings reveal a novel function for the broader class of salicylate-related compounds and highlight the need for additional studies into whether they may impact the efficacy of chemotherapy regimens that include topo II poisons. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Advances in Analog Circuit Design 2015

    CERN Document Server

    Baschirotto, Andrea; Harpe, Pieter


    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.

  16. CMOS analog circuit design

    CERN Document Server

    Allen, Phillip E


    This text presents the principles and techniques for designing analog circuits to be implemented in a CMOS technology. The level is appropriate for seniors and graduate students familiar with basic electronics, including biasing, modeling, circuit analysis, and some familiarity with frequency response. Students learn the methodology of analog integrated circuit design through a hierarchically-oriented approach to the subject that provides thorough background and practical guidance for designing CMOS analog circuits, including modeling, simulation, and testing. The authors' vast industrial experience and knowledge is reflected in the circuits, techniques, and principles presented. They even identify the many common pitfalls that lie in the path of the beginning designer--expert advice from veteran designers. The text mixes the academic and practical viewpoints in a treatment that is neither superficial nor overly detailed, providing the perfect balance.

  17. Analogical Reasoning in Geometry Education (United States)

    Magdas, Ioana


    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…

  18. Electrostatic analogy for symmetron gravity (United States)

    Ogden, Lillie; Brown, Katherine; Mathur, Harsh; Rovelli, Kevin


    The symmetron model is a scalar-tensor theory of gravity with a screening mechanism that suppresses the effect of the symmetron field at high densities characteristic of the Solar System and laboratory scales but allows it to act with gravitational strength at low density on the cosmological scale. We elucidate the screening mechanism by showing that in the quasistatic Newtonian limit there are precise analogies between symmetron gravity and electrostatics for both strong and weak screening. For strong screening we find that large dense bodies behave in a manner analogous to perfect conductors in electrostatics. Based on this analogy we find that the symmetron field exhibits a lightning rod effect wherein the field gradients are enhanced near the ends of pointed or elongated objects. An ellipsoid placed in a uniform symmetron gradient is shown to experience a torque. By symmetry there is no gravitational torque in this case. Hence this effect unmasks the symmetron and might serve as the basis for future laboratory experiments. The symmetron force between a point mass and a large dense body includes a component corresponding to the interaction of the point mass with its image in the larger body. None of these effects have counterparts in the Newtonian limit of Einstein gravity. We discuss the similarities between symmetron gravity and the chameleon model as well as the differences between the two.

  19. Analog signal isolation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Beadle, E.R.


    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  20. Analog signal isolation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Beadle, E.R.


    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  1. Terrestrial Analogs to Mars (United States)

    Farr, T. G.; Arcone, S.; Arvidson, R. W.; Baker, V.; Barlow, N. G.; Beaty, D.; Bell, M. S.; Blankenship, D. D.; Bridges, N.; Briggs, G.; Bulmer, M.; Carsey, F.; Clifford, S. M.; Craddock, R. A.; Dickerson, P. W.; Duxbury, N.; Galford, G. L.; Garvin, J.; Grant, J.; Green, J. R.; Gregg, T. K. P.; Guinness, E.; Hansen, V. L.; Hecht, M. H.; Holt, J.; Howard, A.; Keszthelyi, L. P.; Lee, P.; Lanagan, P. D.; Lentz, R. C. F.; Leverington, D. W.; Marinangeli, L.; Moersch, J. E.; Morris-Smith, P. A.; Mouginis-Mark, P.; Olhoeft, G. R.; Ori, G. G.; Paillou, P.; Reilly, J. F., II; Rice, J. W., Jr.; Robinson, C. A.; Sheridan, M.; Snook, K.; Thomson, B. J.; Watson, K.; Williams, K.; Yoshikawa, K.


    It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests, laboratory measurements (including analysis of Martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel has considered the following two key questions: (1) How do terrestrial analog studies tie in to the Mars Exploration Payload Assessment Group science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel has considered the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

  2. Reasoning through Instructional Analogies (United States)

    Kapon, Shulamit; diSessa, Andrea A.


    This article aims to account for students' assessments of the plausibility and applicability of analogical explanations, and individual differences in these assessments, by analyzing properties of students' underlying knowledge systems. We developed a model of explanation and change in explanation focusing on knowledge elements that provide a…

  3. The Paradox of Analogy

    Directory of Open Access Journals (Sweden)

    David Botting


    Full Text Available I will show that there is a type of analogical reasoning that instantiates a pattern of reasoning in confirmation theory that is considered at best paradoxical and at worst fatal to the entire syntactical approach to confirmation and explanation. However, I hope to elaborate conditions under which this is a sound (although not necessarily strong method of reasoning.

  4. Analogy, explanation, and proof (United States)

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


    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. PMID:25414655

  5. Financial Analysis Analogies for Software Risk


    Masood Uzzafer


    A dynamic software risk assessment model is presented. Analogies between dynamic financial analysis and software risk assessment models are established and based on these analogies it suggested that dynamic risk model for software projects is the way to move forward for the risk assessment of software project. It is shown how software risk assessment change during different phases of a software project and hence requires a dynamic risk assessment model to capture these va...

  6. Protein Structure Prediction with Visuospatial Analogy (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.

  7. High-frequency analog integrated circuit design

    CERN Document Server


    To learn more about designing analog integrated circuits (ICs) at microwave frequencies using GaAs materials, turn to this text and reference. It addresses GaAs MESFET-based IC processing. Describes the newfound ability to apply silicon analog design techniques to reliable GaAs materials and devices which, until now, was only available through technical papers scattered throughout hundred of articles in dozens of professional journals.

  8. A model of the radiation-induced bystander effect based on an analogy with ferromagnets. Application to modelling tissue response in a uniform field (United States)

    Vassiliev, O. N.


    We propose a model of the radiation-induced bystander effect based on an analogy with magnetic systems. The main benefit of this approach is that it allowed us to apply powerful methods of statistical mechanics. The model exploits the similarity between how spin-spin interactions result in correlations of spin states in ferromagnets, and how signalling from a damaged cell reduces chances of survival of neighbour cells, resulting in correlated cell states. At the root of the model is a classical Hamiltonian, similar to that of an Ising ferromagnet with long-range interactions. The formalism is developed in the framework of the Mean Field Theory. It is applied to modelling tissue response in a uniform radiation field. In this case the results are remarkably simple and at the same time nontrivial. They include cell survival curves, expressions for the tumour control probability and effects of fractionation. The model extends beyond of what is normally considered as bystander effects. It offers an insight into low-dose hypersensitivity and into mechanisms behind threshold doses for deterministic effects.

  9. Structure-based design, synthesis and biological testing of etoposide analog epipodophyllotoxin-N-mustard hybrid compounds designed to covalently bind to topoisomerase II and DNA. (United States)

    Yadav, Arun A; Wu, Xing; Patel, Daywin; Yalowich, Jack C; Hasinoff, Brian B


    Drugs that target DNA topoisomerase II isoforms and alkylate DNA represent two mechanistically distinct and clinically important classes of anticancer drugs. Guided by molecular modeling and docking a series of etoposide analog epipodophyllotoxin-N-mustard hybrid compounds were designed, synthesized and biologically characterized. These hybrids were designed to alkylate nucleophilic protein residues on topoisomerase II and thus produce inactive covalent adducts and to also alkylate DNA. The most potent hybrid had a mean GI(50) in the NCI-60 cell screen 17-fold lower than etoposide. Using a variety of in vitro and cell-based assays all of the hybrids tested were shown to target topoisomerase II. A COMPARE analysis indicated that the hybrids had NCI 60-cell growth inhibition profiles matching both etoposide and the N-mustard compounds from which they were derived. These results supported the conclusion that the hybrids displayed characteristics that were consistent with having targeted both topoisomerase II and DNA. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Synthesis, structure-activity relationship and molecular docking of cyclohexenone based analogous as potent non-nucleoside reverse-transcriptase inhibitors (United States)

    Nazar, Muhammad Faizan; Abdullah, Muhammad Imran; Badshah, Amir; Mahmood, Asif; Rana, Usman Ali; Khan, Salah Ud-Din


    The chalcones core in compounds is advantageously chosen effective synthons, which offer exciting perspectives in biological and pharmacological research. The present study reports the successful development of eight new cyclohexenone based anti-reverse transcriptase analogous using rational drug design synthesis principles. These new cyclohexenone derivatives (CDs) were synthesized by following a convenient route of Robinson annulation, and the molecular structure of these CDs were later confirmed by various analytical techniques such as 1H NMR, 13C NMR, FT-IR, UV-Vis spectroscopy and mass spectrometry. All the synthesized compounds were screened theoretically and experimentally against reverse transcriptase (RT) and found potentially active reverse transcriptase (RT) inhibitors. Of the compounds studied, the compound 2FC4 showed high interaction with RT at non-nucleoside binding site, contributing high free binding energy (ΔG -8.01 Kcal) and IC50 (0.207 μg/ml), respectively. Further results revealed that the compounds bearing more halogen groups, with additional hydrophobic character, offered superior anti-reverse transcriptase activity as compared to rest of compounds. It is anticipate that the present study would be very useful for the selection of potential reverse transcriptase inhibitors featuring inclusive pharmacological profiles.

  11. High-resolution W-band ISAR imaging system utilizing a logic-operation-based photonic digital-to-analog converter. (United States)

    Peng, Shaowen; Li, Shangyuan; Xue, Xiaoxiao; Xiao, Xuedi; Wu, Dexin; Zheng, Xiaoping; Zhou, Bingkun


    W-band inverse synthetic aperture radar (ISAR) imaging systems are very useful for automatic target recognition and classification due to their high spatial resolution, high penetration and small antenna size. Broadband linear frequency modulated wave (LFMW) is usually applied to this system for its de-chirping characteristic. However, nearly all of the LFMW generated in electronic W-band ISAR system are based on multipliers and mixers, suffering seriously from electromagnetic interference (EMI) and timing jitter. And photonic-assisted LFMW generator reported before is always limited by bandwidth or time aperture. In this paper, for the first time, we propose and experimentally demonstrate a high-resolution W-band ISAR imaging system utilizing a novel logic-operation-based photonic digital-to-analog converter (LOPDAC). The equivalent sampling rate of the LOPDAC is twice as large as the rate of the digital driving signal. Thus, a broadband LFMW with a large time aperture can be generated by the LOPDAC. This LFMW is up-converted to W band with an optical frequency comb. After photonic-assisted de-chirping processing and data processing to the echo, a high-resolution two-dimension image can be obtained. Experimentally, W-band radar with a time-bandwidth product (TBWP) as large as 79200 (bandwidth 8 GHz; temporal duration 9.9 us) is established and investigated. Results show that the two-dimension (range and cross-range) imaging resolution is ~1.9 cm × ~1.6 cm with a sampling rate of 100 MSa/s in the receiver.

  12. Anatomic Customization of Root-Analog Dental Implants With Cone-Beam CT and CAD/CAM Fabrication: A Cadaver-Based Pilot Evaluation. (United States)

    Evans, Zachary P; Renne, Walter G; Bacro, Thierry R; Mennito, Anthony S; Ludlow, Mark E; Lecholop, Michael K


    Existing root-analog dental implant systems have no standardized protocols regarding retentive design, surface manipulation, or prosthetic attachment design relative to the site's unique anatomy. Historically, existing systems made those design choices arbitrarily. For this report, strategies were developed that deliberately reference the adjacent anatomy, implant and restorable path of draw, and bone density for implant and retentive design. For proof of concept, dentate arches from human cadavers were scanned using cone-beam computed tomography and then digitally modeled. Teeth of interest were virtually extracted and manipulated via computer-aided design to generate root-analog implants from zirconium. We created a stepwise protocol for analyzing and developing the implant sites, implant design and retention, and prosthetic emergence and connection all from the pre-op cone-beam data. Root-analog implants were placed at the time of extraction and examined radiographically and mechanically concerning ideal fit and stability. This study provides proof of concept that retentive root-analog implants can be produced from cone-beam data while improving fit, retention, safety, esthetics, and restorability when compared to the existing protocols. These advancements may provide the critical steps necessary for clinical relevance and success of immediately placed root-analog implants. Additional studies are necessary to validate the model prior to clinical trial.

  13. Structure-activity relationship of cinnamaldehyde analogs as inhibitors of AI-2 based quorum sensing and their effect on virulence of Vibrio spp. (United States)

    Brackman, Gilles; Celen, Shari; Hillaert, Ulrik; Van Calenbergh, Serge; Cos, Paul; Maes, Louis; Nelis, Hans J; Coenye, Tom


    Many bacteria, including Vibrio spp., regulate virulence gene expression in a cell-density dependent way through a communication process termed quorum sensing (QS). Hence, interfering with QS could be a valuable novel antipathogenic strategy. Cinnamaldehyde has previously been shown to inhibit QS-regulated virulence by decreasing the DNA-binding ability of the QS response regulator LuxR. However, little is known about the structure-activity relationship of cinnamaldehyde analogs. By evaluating the QS inhibitory activity of a series of cinnamaldehyde analogs, structural elements critical for autoinducer-2 QS inhibition were identified. These include an α,β unsaturated acyl group capable of reacting as Michael acceptor connected to a hydrophobic moiety and a partially negative charge. The most active cinnamaldehyde analogs were found to affect the starvation response, biofilm formation, pigment production and protease production in Vibrio spp in vitro, while exhibiting low cytotoxicity. In addition, these compounds significantly increased the survival of the nematode Caenorhabditis elegans infected with Vibrio anguillarum, Vibrio harveyi and Vibrio vulnificus. Several new and more active cinnamaldehyde analogs were discovered and they were shown to affect Vibrio spp. virulence factor production in vitro and in vivo. Although ligands for LuxR have not been identified so far, the nature of different cinnamaldehyde analogs and their effect on the DNA binding ability of LuxR suggest that these compounds act as LuxR-ligands.

  14. Structure-activity relationship of cinnamaldehyde analogs as inhibitors of AI-2 based quorum sensing and their effect on virulence of Vibrio spp.

    Directory of Open Access Journals (Sweden)

    Gilles Brackman

    Full Text Available BACKGROUND: Many bacteria, including Vibrio spp., regulate virulence gene expression in a cell-density dependent way through a communication process termed quorum sensing (QS. Hence, interfering with QS could be a valuable novel antipathogenic strategy. Cinnamaldehyde has previously been shown to inhibit QS-regulated virulence by decreasing the DNA-binding ability of the QS response regulator LuxR. However, little is known about the structure-activity relationship of cinnamaldehyde analogs. METHODOLOGY/PRINCIPAL FINDINGS: By evaluating the QS inhibitory activity of a series of cinnamaldehyde analogs, structural elements critical for autoinducer-2 QS inhibition were identified. These include an α,β unsaturated acyl group capable of reacting as Michael acceptor connected to a hydrophobic moiety and a partially negative charge. The most active cinnamaldehyde analogs were found to affect the starvation response, biofilm formation, pigment production and protease production in Vibrio spp in vitro, while exhibiting low cytotoxicity. In addition, these compounds significantly increased the survival of the nematode Caenorhabditis elegans infected with Vibrio anguillarum, Vibrio harveyi and Vibrio vulnificus. CONCLUSIONS/SIGNIFICANCE: Several new and more active cinnamaldehyde analogs were discovered and they were shown to affect Vibrio spp. virulence factor production in vitro and in vivo. Although ligands for LuxR have not been identified so far, the nature of different cinnamaldehyde analogs and their effect on the DNA binding ability of LuxR suggest that these compounds act as LuxR-ligands.

  15. Pan-pathway based interaction profiling of FDA-approved nucleoside and nucleobase analogs with enzymes of the human nucleotide metabolism.

    Directory of Open Access Journals (Sweden)

    Louise Egeblad

    Full Text Available To identify interactions a nucleoside analog library (NAL consisting of 45 FDA-approved nucleoside analogs was screened against 23 enzymes of the human nucleotide metabolism using a thermal shift assay. The method was validated with deoxycytidine kinase; eight interactions known from the literature were detected and five additional interactions were revealed after the addition of ATP, the second substrate. The NAL screening gave relatively few significant hits, supporting a low rate of "off target effects." However, unexpected ligands were identified for two catabolic enzymes guanine deaminase (GDA and uridine phosphorylase 1 (UPP1. An acyclic guanosine prodrug analog, valaciclovir, was shown to stabilize GDA to the same degree as the natural substrate, guanine, with a ΔT(agg around 7°C. Aciclovir, penciclovir, ganciclovir, thioguanine and mercaptopurine were also identified as ligands for GDA. The crystal structure of GDA with valaciclovir bound in the active site was determined, revealing the binding of the long unbranched chain of valaciclovir in the active site of the enzyme. Several ligands were identified for UPP1: vidarabine, an antiviral nucleoside analog, as well as trifluridine, idoxuridine, floxuridine, zidovudine, telbivudine, fluorouracil and thioguanine caused concentration-dependent stabilization of UPP1. A kinetic study of UPP1 with vidarabine revealed that vidarabine was a mixed-type competitive inhibitor with the natural substrate uridine. The unexpected ligands identified for UPP1 and GDA imply further metabolic consequences for these nucleoside analogs, which could also serve as a starting point for future drug design.

  16. Pan-pathway based interaction profiling of FDA-approved nucleoside and nucleobase analogs with enzymes of the human nucleotide metabolism. (United States)

    Egeblad, Louise; Welin, Martin; Flodin, Susanne; Gräslund, Susanne; Wang, Liya; Balzarini, Jan; Eriksson, Staffan; Nordlund, Pär


    To identify interactions a nucleoside analog library (NAL) consisting of 45 FDA-approved nucleoside analogs was screened against 23 enzymes of the human nucleotide metabolism using a thermal shift assay. The method was validated with deoxycytidine kinase; eight interactions known from the literature were detected and five additional interactions were revealed after the addition of ATP, the second substrate. The NAL screening gave relatively few significant hits, supporting a low rate of "off target effects." However, unexpected ligands were identified for two catabolic enzymes guanine deaminase (GDA) and uridine phosphorylase 1 (UPP1). An acyclic guanosine prodrug analog, valaciclovir, was shown to stabilize GDA to the same degree as the natural substrate, guanine, with a ΔT(agg) around 7°C. Aciclovir, penciclovir, ganciclovir, thioguanine and mercaptopurine were also identified as ligands for GDA. The crystal structure of GDA with valaciclovir bound in the active site was determined, revealing the binding of the long unbranched chain of valaciclovir in the active site of the enzyme. Several ligands were identified for UPP1: vidarabine, an antiviral nucleoside analog, as well as trifluridine, idoxuridine, floxuridine, zidovudine, telbivudine, fluorouracil and thioguanine caused concentration-dependent stabilization of UPP1. A kinetic study of UPP1 with vidarabine revealed that vidarabine was a mixed-type competitive inhibitor with the natural substrate uridine. The unexpected ligands identified for UPP1 and GDA imply further metabolic consequences for these nucleoside analogs, which could also serve as a starting point for future drug design.

  17. Analogy, Explanation, and Proof

    Directory of Open Access Journals (Sweden)

    John eHummel


    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.

  18. Component Processes in Analogical Reasoning (United States)

    Sternberg, Robert J.


    Describes alternative theoretical positions regarding (a) the component information processes used in analogical reasoning and (b) strategies for combining these processes. Also presents results from three experiments on analogical reasoning. (Author/RK)

  19. Analog computing by Brewster effect. (United States)

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


    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.

  20. Evaluation of peak overlap in migration-time distributions determined by organelle capillary electrophoresis: Type-II error analogy based on statistical-overlap theory. (United States)

    Davis, Joe M; Arriaga, Edgar A


    Organelles commonly are separated by capillary electrophoresis (CE) with laser-induced-fluorescence detection. Usually, it is assumed that peaks observed in the CE originate from single organelles, with negligible occurrence of peak overlap. Under this assumption, migration-time and mobility distributions are obtained by partitioning the CE into different regions and counting the number of observed peaks in each region. In this paper, criteria based on statistical-overlap theory (SOT) are developed to test the assumption of negligible peak overlap and to predict conditions for its validity. For regions of the CE having constant peak density, the numbers of peaks (i.e., intensity profiles of single organelles) and observed peaks (i.e., maxima) are modeled by probability distributions. For minor peak overlap, the distributions partially merge, and their mergence is described by an analogy to the Type-II error of hypothesis testing. Criteria are developed for the amount of peak overlap, at which the number of observed peaks has an 85% or 90% probability of lying within the 95% confidence interval of the number of peaks of single organelles. For this or smaller amounts of peak overlap, the number of observed peaks is a good approximation to the number of peaks. A simple procedure is developed for evaluating peak overlap, requiring determination of only the peak standard deviation, the duration of the region occupied by peaks, and the number of observed peaks in the region. The procedure can be applied independently to each region of the partitioned CE. The procedure is applied to a mitochondrial CE.

  1. 21 Days head-down bed rest induces weakening of cell-mediated immunity - Some spaceflight findings confirmed in a ground-based analog. (United States)

    Kelsen, Jens; Bartels, Lars Erik; Dige, Anders; Hvas, Christian Lodberg; Frings-Meuthen, Petra; Boehme, Gisela; Thomsen, Marianne Kragh; Fenger-Grøn, Morten; Dahlerup, Jens Frederik


    Several studies indicate a weakening of cell-mediated immunity (CMI) and reactivation of latent herpes viruses during spaceflight. We tested the hypothesis that head-down bed rest (HDBR), a ground-based analog of spaceflight, mimics the impact of microgravity on human immunity. Seven healthy young males underwent two periods of 3 weeks HDBR in the test facility of the German Aerospace Center. As a nutritional countermeasure aimed against bone demineralisation, 90 mmol potassium bicarbonate (KHCO(3)) was administered daily in a crossover design. Blood samples were drawn on five occasions. Whole blood was stimulated with antigen i.e. Candida albicans, purified protein derivative (PPD) tuberculin, tetanus toxoid and Cytomegalovirus (CMV) (CMV-QuantiFERON). Flow cytometric analysis included CD4(+)CD25(+)CD127(-)FOXP3(+) regulatory T cells (Tregs), γδ T cells, B cells, NK cells and dendritic cells. In one of the two bed rest periods, we observed a significant decrease in production of interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) following phytohemagglutinin (PHA) stimulation, with a rapid normalization being observed after HDBR. The cytokine levels showed a V-shaped pattern that led to a relativeTh2-shift in cytokine balance. Only three individuals responded to the specific T cell antigens without showing signs of an altered response during HDBR, nor did we observe reactivation of CMV or Epstein-Barr virus (EBV). Of unknown significance, dietary supplementation with KHCO(3) counteracted the decrease in IL-2 levels during HDBR, while there was no impact on other immunological parameters. We conclude that discrete alterations in CMI may be induced by HDBR in selected individuals. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Analogical Reasoning and Computer Programming. (United States)

    Clement, Catherine A.; And Others


    A study of correlations between analogical reasoning and Logo programming mastery among female high school students related the results of pretests of analogical reasoning to posttests of programming mastery. A significant correlation was found between analogical reasoning and the ability to write subprocedures for use in several different…

  3. Synthesis of 8-amino and 8-substituted amino derivatives of acyclic purine nucleoside and nucleotide analogs. Alkylation of 8-substituted purine bases

    Czech Academy of Sciences Publication Activity Database

    Janeba, Zlatko; Holý, Antonín


    Roč. 20, 4-7 (2001), s. 1103-1106 ISSN 1525-7770 R&D Projects: GA ČR GV203/96/K001 Institutional research plan: CEZ:AV0Z4055905 Keywords : nucleotide analogs Subject RIV: CC - Organic Chemistry Impact factor: 0.508, year: 2001

  4. ESD analog circuits and design

    CERN Document Server

    Voldman, Steven H


    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

  5. Space flight nutrition research: platforms and analogs (United States)

    Smith, Scott M.; Uchakin, Peter N.; Tobin, Brian W.


    Conducting research during actual or simulated weightlessness is a challenging endeavor, where even the simplest activities may present significant challenges. This article reviews some of the potential obstacles associated with performing research during space flight and offers brief descriptions of current and previous space research platforms and ground-based analogs, including those for human, animal, and cell-based research. This review is intended to highlight the main issues of space flight research analogs and leave the specifics for each physiologic system for the other papers in this section.

  6. Albert Einstein, Analogizer Extraordinaire

    CERN Multimedia

    CERN. Geneva


    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.

  7. Analog forecasting with dynamics-adapted kernels (United States)

    Zhao, Zhizhen; Giannakis, Dimitrios


    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.

  8. Paper-based solid-phase multiplexed nucleic acid hybridization assay with tunable dynamic range using immobilized quantum dots as donors in fluorescence resonance energy transfer. (United States)

    Noor, M Omair; Krull, Ulrich J


    A multiplexed solid-phase nucleic acid hybridization assay on a paper-based platform is presented using multicolor immobilized quantum dots (QDs) as donors in fluorescence resonance energy transfer (FRET). The surface of paper was modified with imidazole groups to immobilize two types of QD-probe oligonucleotide conjugates that were assembled in solution. Green-emitting QDs (gQDs) and red-emitting QDs (rQDs) served as donors with Cy3 and Alexa Fluor 647 (A647) acceptors. The gQD/Cy3 FRET pair served as an internal standard, while the rQD/A647 FRET pair served as a detection channel, combining the control and analytical test zones in one physical location. Hybridization of dye-labeled oligonucleotide targets provided the proximity for FRET sensitized emission from the acceptor dyes, which served as an analytical signal. Hybridization assays in the multicolor format provided a limit of detection of 90 fmol and an upper limit of dynamic range of 3.5 pmol. The use of an array of detection zones was designed to provide improved analytical figures of merit compared to that which could be achieved on one type of array design in terms of relative concentration of multicolor QDs. The hybridization assays showed excellent resistance to nonspecific adsorption of oligonucleotides. Selectivity of the two-plex hybridization assay was demonstrated by single nucleotide polymorphism (SNP) detection at a contrast ratio of 50:1. Additionally, it is shown that the use of preformed QD-probe oligonucleotide conjugates and consideration of the relative number density of the two types of QD-probe conjugates in the two-color assay format is advantageous to maximize assay sensitivity and the upper limit of dynamic range.

  9. A Calibration Method for Nonlinear Mismatches in M-Channel Time-Interleaved Analog-to-Digital Converters Based on Hadamard Sequences

    Directory of Open Access Journals (Sweden)

    Husheng Liu


    Full Text Available The time-interleaved analog-to-digital converter (TIADC is an architecture used to achieve a high sampling rate and high dynamic performance. However, estimation and compensation methods are required to maintain the dynamic performance of the constituent analog-to-digital converters (ADCs due to channel mismatches. This paper proposes a blind adaptive method to calibrate the nonlinear mismatches in M-channel TIADCs (M-TIADCs. The nonlinearity-induced error signal is reconstructed by the proposed multiplier Hadamard transform (MHT structure, and the nonlinear parameters are estimated by the filtered-X least-mean square (FxLMS algorithm. The performance of cascade calibration is also analyzed. The numerical simulation results show that the proposed method consumes much less hardware resources while maintaining the calibration performance.

  10. Detecting analogical resemblance without retrieving the source analogy. (United States)

    Kostic, Bogdan; Cleary, Anne M; Severin, Kaye; Miller, Samuel W


    We examined whether people can detect analogical resemblance to an earlier experimental episode without being able to recall the experimental source of the analogical resemblance. We used four-word analogies (e.g., robin-nest/beaver-dam), in a variation of the recognition-without-cued-recall method (Cleary, 2004). Participants studied word pairs (e.g., robin-nest) and were shown new word pairs at test, half of which analogically related to studied word pairs (e.g., beaver-dam) and half of which did not. For each test pair, participants first attempted to recall an analogically similar pair from the study list. Then, regardless of whether successful recall occurred, participants were prompted to rate the familiarity of the test pair, which was said to indicate the likelihood that a pair that was analogically similar to the test pair had been studied. Across three experiments, participants demonstrated an ability to detect analogical resemblance without recalling the source analogy. Findings are discussed in terms of their potential relevance to the study of analogical reasoning and insight, as well as to the study of familiarity and recognition memory.

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

    CERN Document Server

    Williams, Jim


    * 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

  12. FASTBUS 16-channel 8-bit analog-to-digital converter

    International Nuclear Information System (INIS)

    Parfenov, A.N.; Pilyar, A.V.


    The converter module is based on 1107PV3 microcircuits connected in cascade connection. The measured analog signals range is ±2 V. Analog-to-digital conversion is linear. Information from analog-to-digital converter (ADC) is read simultaneously from two channels using FASTBUS channel for ∼40 ns. 16-channel ADC is used in a system to measure characteristics of scintillation hodoscopes module of the SFERA set-up

  13. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin


    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...

  14. A fast multichannel analog storage system

    International Nuclear Information System (INIS)

    Freytag, D.R.


    A Multichannel Analog Storage System based on a commercial 32-channel parallel in/serial out (PISO) analog shift register is described. The basic unit is a single width CAMAC module containing 512 analog cells and the associated logic for data storage and subsequent readout. At sampling rates of up to 30 MHz the signals are strobed directly into the PISO. At higher rates signals are strobed into a fast presampling stage and subsequently transferred in block form into an array of PISO's. Sampling rates of 300 MHz have been achieved with the present device and 1000 MHz are possible with improved signal drivers. The system is well suited for simultaneous handling of many signal channels with moderate numbers of samples in each channel. RMS noise over full scale signal has been measured as 1:3000 (approx. =11 bit). However, nonlinearities in the response and differences in sensitivity of the analog cells require an elaborate calibration system in order to realize 11 bit accuracy for the analog information

  15. Beginning analog electronics through projects

    CERN Document Server

    Singmin, Andrew


    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

  16. Associative Pattern Recognition In Analog VLSI Circuits (United States)

    Tawel, Raoul


    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.

  17. Analog processor for electroluminescent detector

    International Nuclear Information System (INIS)

    Belkin, V.S.


    Analog processor for spectrometric channel of soft X-ray radiation electroluminescent detector is described. Time internal spectrometric measurer (TIM) with 1 ns/chan quick action serves as signal analyzer. Analog processor restores signals direct component, integrates detector signals and generates control pulses on the TIM input, provides signal discrimination by amplitude and duration, counts number of input pulses per measuring cycle. Flowsheet of analog processor and its man characteristics are presented. Analog processor dead time constitutes 0.5-5 ms. Signal/noise relation is ≥ 500. Scale integral nonlinearity is < 2%

  18. Compact Structural Test Generation for Analog Macros

    NARCIS (Netherlands)

    Kaal, V.; Kerkhoff, Hans G.


    A structural, fault-model based methodology for the generation of compact high-quality test sets for analog macros is presented. Results are shown for an IV-converter macro design. Parameters of so-called test configurations are optimized for detection of faults in a fault-list and an optimal

  19. Plasma analog of particle-pair production

    International Nuclear Information System (INIS)

    Tsidulko, Yu.A.; Berk, H.L.


    It is shown that the plasma axial shear flow instability satisfies the Klein-Gordon equation. The plasma instability is then shown to be analogous to spontaneous particle-pair production when a potential energy is present that is greater than twice the particle rest mass energy. Stability criteria can be inferred based on field theoretical conservation laws

  20. Creative Analogy Use in a Heterogeneous Design Team

    DEFF Research Database (Denmark)

    Christensen, Bo; Ball, Linden J.


    We integrated two research traditions – one focusing on analogical reasoning, the other on knowledge sharing – with the aim of examining how designers' unique knowledge backgrounds can fuel analogy-based creativity. The present dataset afforded a unique opportunity to pursue this aim since...... associated with increased epistemic uncertainty, perhaps because domain experts appreciate the challenge of mapping such analogies between domains. Our findings support claims from the knowledge-sharing literature for a direct route from knowledge diversity through analogical reasoning to novel idea...... 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...

  1. [Analogies and analogy research in technical biology and bionics]. (United States)

    Nachtigall, Werner


    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.

  2. Children's Development of Analogical Reasoning: Insights from Scene Analogy Problems (United States)

    Richland, Lindsey E.; Morrison, Robert G.; Holyoak, Keith J.


    We explored how relational complexity and featural distraction, as varied in scene analogy problems, affect children's analogical reasoning performance. Results with 3- and 4-year-olds, 6- and 7-year-olds, 9- to 11-year-olds, and 13- and 14-year-olds indicate that when children can identify the critical structural relations in a scene analogy…

  3. 25th workshop on Advances in Analog Circuit Design

    CERN Document Server

    Harpe, Pieter; Makinwa, Kofi


    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.

  4. Conjecturing via Reconceived Classical Analogy (United States)

    Lee, Kyeong-Hwa; Sriraman, Bharath


    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…

  5. Drawing Analogies in Environmental Education (United States)

    Affifi, Ramsey


    Reconsidering the origin, process, and outcomes of analogy-making suggests practices for environmental educators who strive to disengage humans from the isolating illusions of dichotomizing frameworks. We can view analogies as outcomes of developmental processes within which human subjectivity is but an element, threading our sense of self back…

  6. Musik som analogi og metafor

    DEFF Research Database (Denmark)

    Bonde, Lars Ole


    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...

  7. Stereoselective synthesis of nicotinamide beta-riboside and nucleoside analogs. (United States)

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


    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.

  8. Using Analogies to Prevent Misconceptions about Chemical Equilibrium (United States)

    Sahin Pekmez, Esin


    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)…

  9. Neuroscientific Insights into the Development of Analogical Reasoning (United States)

    Whitaker, Kirstie J.; Vendetti, Michael S.; Wendelken, Carter; Bunge, Silvia A.


    Analogical reasoning, or the ability to find correspondences between entities based on shared relationships, supports knowledge acquisition. As such, the development of this ability during childhood is thought to promote learning. Here, we sought to better understand the mechanisms by which analogical reasoning about semantic relations improves…

  10. Analogical Reasoning in Children with Specific Language Impairment (United States)

    Leroy, Sandrine; Parisse, Christophe; Maillart, Christelle


    Usage-based theory considers analogical reasoning as a cognitive process required in language development. We hypothesized that difficulties with analogical reasoning could hinder the abstraction of construction schemas, thus slowing down morphosyntactic development for children with specific language impairment (SLI). We also hypothesized, in…

  11. Towards Analogy-based Recommendation : Benchmarking of Perceived Analogy Semantics

    NARCIS (Netherlands)

    Lofi, C.; Tintarev, N.; Bogers, T.; Koolen, M.; Mobasher, B.; Said, A.; Tuzhilin, A.


    Requests for recommendation can be seen as a form of query for candidate items, ranked by relevance. Users are however o‰en
    unable to crisply de€ne what they are looking for. One of the core concepts of natural communication for describing and explaining
    complex information needs in an

  12. [Efficacy of initial antiretroviral therapy based on lopinavir/ritonavir plus 2 nucleoside/nucleotide analogs in patients with human immunodeficiency virus type 1 infection]. (United States)

    Zamora, Laura; Gatell, José M


    Triple combination regimens consisting of lopinavir/ritonavir (LPV/r) plus 2 nucleoside/nucleotide analogs continue to be a valid option in initial antiretroviral therapy. Other protease inhibitors boosted with ritonavir (and in future with cobicistat) have been introduced, as well as other non-nucleoside analogs (rilpivirin) and 3 integrase inhibitors. None of the new regimens have shown superiority over LPV/r or comparisons are lacking. Therefore, regimens including LPV/r continue to be recommended as initial first-line or alternative strategies in most treatment guidelines. Dual combinations with LPV/r (plus raltegravir or lamivudine) are described in another article and can provide a similar response rate to triple combinations, better tolerance, and an improved cost-efficacy ratio, both for initial therapy and in simplification strategies. In contrast, LPV/r or darunavir/r monotherapy does not seem an acceptable option in treatment-naïve patients and is becoming increasingly less acceptable in simplification strategies. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  13. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J M


    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...

  14. A CAMAC unit for charge measuring and pulse shape recording based on a fast, 8-bit parallel analog-to-digital converter

    International Nuclear Information System (INIS)

    Kulka, Z.; Kreciejewski, M.; Nadachowski, M.


    A device designed mainly for measuring systems for testing parameters of some type of detectors used in the high energy physics is described. The device is one-module CAMAC unit. It is equipped in a fast, 8-bit parallel analog-to-digital converter ''flash''type with a gated integrator at the input and a static RAM (4096 x 8 bit) at the output. The device enables measurements of the charge in pulses from detectors or registration of the shape of these pulses. The construction, operation and parameters of the circuits of the device are described and the way of programming functions using CAMAC dataway is given. 8 refs., 9 figs. (author)

  15. Diphtheria Toxin- and GFP-Based Mouse Models of Acquired Hypoparathyroidism and Treatment With a Long-Acting Parathyroid Hormone Analog. (United States)

    Bi, Ruiye; Fan, Yi; Lauter, Kelly; Hu, Jing; Watanabe, Tomoyuki; Cradock, Jim; Yuan, Quan; Gardella, Thomas; Mannstadt, Michael


    Hypoparathyroidism (HP) arises most commonly from parathyroid (PT) gland damage associated with neck surgery, and is typically treated with oral calcium and active vitamin D. Such treatment effectively increases levels of serum calcium (sCa), but also brings risk of hypercalciuria and renal damage. There is thus considerable interest in using PTH or PTH analogs to treat HP. To facilitate study of this disease and the assessment of new treatment options, we developed two mouse models of acquired HP, and used them to assess efficacy of PTH(1-34) as well as a long-acting PTH analog (LA-PTH) in regulating blood calcium levels. In one model, we used PTHcre-iDTR mice in which the diphtheria toxin (DT) receptor (DTR) is selectively expressed in PT glands, such that systemic DT administration selectively ablates parathyroid cells. For the second model, we generated GFP-PT mice in which green fluorescent protein (GFP) is selectively expressed in PT cells, such that parathyroidectomy (PTX) is facilitated by green fluorescence of the PT glands. In the PTHcre-iDTR mice, DT injection (2 × 5 μg/kg, i.p.) resulted in moderate yet consistent reductions in serum PTH and sCa levels. The more severe hypoparathyroid phenotype was observed in GFP-PT mice following GFP-guided PTX surgery. In each model, a single subcutaneous injection of LA-PTH increased sCa levels more effectively and for a longer duration (>24 hours) than did a 10-fold higher dose of PTH(1-34), without causing excessive urinary calcium excretion. These new mouse models thus faithfully replicate two degrees of acquired HP, moderate and severe, and may be useful for assessing potential new modes of therapy. © 2015 American Society for Bone and Mineral Research. © 2015 American Society for Bone and Mineral Research.

  16. Molecular modeling of fentanyl analogs

    Directory of Open Access Journals (Sweden)



    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.

  17. Gemini analogs of vitamin D. (United States)

    Pazos, Gonzalo; Rivadulla, Marcos L; Pérez-García, Xenxo; Gandara, Zoila; Pérez, Manuel


    The Gemini analogs are the last significant contribution to the family of vitamin D derivatives in medicine, for the treatment of cancer. The first Gemini analog was characterized by two symmetric side chains at C-20. Following numerous modifications, the most active analog bears a C-23-triple bond, C-26, 27- hexafluoro substituents on one side chain and a terminal trideuteromethylhydroxy group on the other side chain. This progression was possible due to improvements in the synthetic methods for the preparation of these derivatives, which allowed for increasing molecular complexity and complete diastereoselective control at C-20 and the substituted sidechains.

  18. Analog Systems for Gravity Duals


    Hossenfelder, S.


    We show that analog gravity systems exist for charged, planar black holes in asymptotic Anti-de Sitter space. These black holes have been employed to describe, via the gauge-gravity duality, strongly coupled condensed matter systems on the boundary of AdS-space. The analog gravity system is a different condensed matter system that, in a suitable limit, describes the same bulk physics as the theory on the AdS boundary. This combination of the gauge-gravity duality and analog gravity therefore ...

  19. Analog and digital dividers for mass spectrometers

    International Nuclear Information System (INIS)

    Osipov, A.K.


    Errors of four different types of stress dividers used in statical mass-spectrometers for determination of mass number by accelerating stress are analyzed. The simplest flowsheet of the analog divider comprises operation amplifier, in the chain of the negative feedback of which a multiplication device on differential cascade is switched- in. This analog divider has high sensitivity to temperature and high error approximately 5%. Application of the multiplier on differential cascade with normalization permits to increase temperature stability and decrease the error up to 1%. Another type of the analog divider is a logarithmic divider the error of which is constant within the whole operation range and it constitutes 1-5%. The digital divider with a digital-analog transformer (DAT) has the error of +-0.015% which is determined by the error of detectors and resistance of keys in the locked state. Considered is the design of a divider based on transformation of the inlet stress into the time period. The error of the divider is determined in this case mainly by stress of the zero shift of the operation amplifier (it should be compensated) and relative threshold stability of the comparator triggering which equals (2-3)x10 -4 . It is noted that the divider with DAT application and the divider with the use of stress transformation within the time period are most perspective ones for statical mass-spectrometers [ru

  20. Analog filters in nanometer CMOS

    CERN Document Server

    Uhrmann, Heimo; Zimmermann, Horst


    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 ...

  1. How strategists really think. Tapping the power of analogy. (United States)

    Gavetti, Giovanni; Rivkin, Jan W


    Leaders tend to be so immersed in the specifics of strategy that they rarely stop to think how much of their reasoning is done by analogy. As a result, they miss useful insights that psychologists and other scientists have generated about analogies' pitfalls. Managers who pay attention to their own analogical thinking will make better strategic decisions and fewer mistakes. Charles Lazarus was inspired by the supermarket when he founded Toys R Us; Intel promoted its low-end chips to avoid becoming like U.S. Steel; and Circuit City created CarMax because it saw the used-car market as analogous to the consumer-electronics market. Each example displays the core elements of analogical reasoning: a novel problem or a new opportunity, a specific prior context that managers deem to be similar in its essentials, and a solution that managers can transfer from its original setting to the new one. Analogical reasoning is a powerful tool for sparking breakthrough ideas. But dangers arise when analogies are built on surface similarities (headlong diversification based on loose analogies played a role in Enron's collapse, for instance). Psychologists have discovered that it's all too easy to overlook the superficiality of analogies. The situation is further complicated by people's tendency to hang on to beliefs even after contrary evidence comes along (a phenomenon known as anchoring) and their tendency to seek only the data that confirm their beliefs (an effect known as the confirmation bias). Four straightforward steps can improve a management team's odds of using an analogy well: Recognize the analogy and identify its purpose; thoroughly understand its source; determine whether the resemblance is more than superficial; and decide whether the original strategy, properly translated, will work in the target industry.

  2. The Effect of Mini-PEG-Based Spacer Length on Binding and Pharmacokinetic Properties of a 68Ga-Labeled NOTA-Conjugated Antagonistic Analog of Bombesin

    Directory of Open Access Journals (Sweden)

    Zohreh Varasteh


    Full Text Available The overexpression of gastrin-releasing peptide receptor (GRPR in cancer can be used for peptide-receptor mediated radionuclide imaging and therapy. We have previously shown that an antagonist analog of bombesin RM26 conjugated to 1,4,7-triazacyclononane-N,N',N''-triacetic acid (NOTA via a diethyleneglycol (PEG2 spacer (NOTA-PEG2-RM26 and labeled with 68Ga can be used for imaging of GRPR-expressing tumors. In this study, we evaluated if a variation of mini-PEG spacer length can be used for optimization of targeting properties of the NOTA-conjugated RM26. A series of analogs with different PEG-length (n = 2, 3, 4, 6 was synthesized, radiolabeled and evaluated in vitro and in vivo. The IC50 values of natGa-NOTA-PEGn-RM26 (n = 2, 3, 4, 6 were 3.1 ± 0.2, 3.9 ± 0.3, 5.4 ± 0.4 and 5.8 ± 0.3 nM, respectively. In normal mice all conjugates demonstrated similar biodistribution pattern, however 68Ga-NOTA-PEG3-RM26 showed lower liver uptake. Biodistribution of 68Ga-NOTA-PEG3-RM26 was evaluated in nude mice bearing PC-3 (prostate cancer and BT-474 (breast cancer xenografts. High uptake in tumors (4.6 ± 0.6%ID/g and 2.8 ± 0.4%ID/g for PC-3 and BT-474 xenografts, respectively and high tumor-to-background ratios (tumor/blood of 44 ± 12 and 42 ± 5 for PC-3 and BT-474 xenografts, respectively were found already at 2 h p.i. of 68Ga-NOTA-PEG3-RM26. Results of this study suggest that variation in the length of the PEG spacer can be used for optimization of targeting properties of peptide-chelator conjugates. However, the influence of the mini-PEG length on biodistribution is minor when di-, tri-, tetra- and hexaethylene glycol are compared.

  3. Source selection for analogical reasoning an empirical approach

    Energy Technology Data Exchange (ETDEWEB)

    Stubblefield, W.A. [Sandia National Labs., Albuquerque, NM (United States); Luger, G.F. [Univ. of New Mexico, Albuquerque, NM (United States)


    The effectiveness of an analogical reasoner depends upon its ability to select a relevant analogical source. In many problem domains, however, too little is known about target problems to support effective source selection. This paper describes the design and evaluation of SCAVENGER, an analogical reasoner that applies two techniques to this problem: (1) An assumption-based approach to matching that allows properties of candidate sources to match unknown target properties in the absence of evidence to the contrary. (2) The use of empirical learning to improve memory organization based on problem solving experience.

  4. Combined analog-to-digital converter

    International Nuclear Information System (INIS)

    Zhukov, A.V.; Rzhendinskaya, S.N.


    A 10-bit analog-to-digital converter (ADC) designed for operating in spectrometers with time-dependent filters is described. The ADC operation is based on combining the parallel reading and sequential counting methods. At maximum conversion time of 12 μs, timing series frequency of 25 MHz and foUr reference levels the differential nonlinearity withoUt statistical smoothing (maximum relative channel width deviation from average value) is not more than 4%

  5. Atomtronics: Ultracold Atom Analogs of Electronic Devices (United States)


    to leave the base compared to entering the col- build a transistor . Bipolar junction transistors ( BJT ) lector. Because of this, most of the current...voltage curve exploits the existence of superfluid and insulating regimes in the phase diagram. "lie atomt.roinc analog of a bipolar junction transistor ...of a bipolar junction transistor exhibits large negative gain. Our results provide the building blocks for more advanced atomtronic devices and

  6. Resizing methodology for CMOS analog circuit


    Levi, Timothée; Tomas, J.; Lewis, N.; Fouillat, P.


    International audience; This paper proposes a CMOS resizing methodology for analog circuits during a technology migration. The scaling rules aim to be easy to apply and are based on the simplest MOS transistor model. The principle is to transpose one circuit topology from one technology to another, while keeping the main figures of merit, and the issue is to quickly calculate the new transistor dimensions. Furthermore, when the target technology has smaller minimum length, we expect to obtain...

  7. Learning Plate Tectonics Using a Pre-Analogy Step (United States)

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


    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.

  8. Analog approach to mixed analog-digital circuit simulation (United States)

    Ogrodzki, Jan


    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.

  9. Physico-Chemical, and Sensory Properties of Soy Based Gouda Cheese Analog Made from Different Concentration of Fat, Sodium Citrate and Various Cheese Starter Cultures

    Directory of Open Access Journals (Sweden)

    Abu Amar


    Full Text Available Gouda cheese analog (GCA was made using soy protein isolate (SPI, skim milk powder (SMP, fat (palm fat and butter fat, and water (W at optimal ratio of SPI : SMP : F : W = 14 : 6 : 20 : 60. The effects of butter fat, sodium citrate, and cheese starter culture on the sensory properties of ripened product were assessed by preference test, hedonic test, and the texture profile analysis (TPA of GCA. The free fatty acids, water-soluble nitrogen, and reduction in pH value of progel were also measured. The use of 100% butter fat (BF produced strong Gouda flavor. It could be due to the fatty acids content in BF; in contrast, product with 100% palm fat (PF produced tasteless GCA. It might be due to fatty acids content in PF, middle, and long chain fatty acids. Single cheese starter culture could not develop Gouda flavor during ripening. The use of mixed fat (50% BF and 50% PF and mixed cheese starter culture together with Brevibacterium linens developed a suitable characteristic flavor of Gouda product during ripening. The addition of 0.5% sodium citrate could improve the flavor; nevertheless, it reduced the stability of texture.

  10. A Systematic Evaluation of Analogs for the Read-across Prediction of Estrogenicity (SOT) (United States)

    Read-across is a data gap filling technique widely used within category and analog approaches to predict a biological property for a target data-poor chemical using known information from similar (source analog) chemical(s). Potential source analogs are typically identified base...

  11. An analogy strategy for transformation optics

    International Nuclear Information System (INIS)

    Yao, Kan; Liu, Yongmin; Chen, Huanyang; Jiang, Xunya


    We introduce an analogy strategy to design transformation optical devices. Based on the similarities between field lines in different physical systems, the trajectories of light can be intuitively determined to curve in a gentle manner, and the resulting materials are isotropic and nonmagnetic. Furthermore, the physical meaning of the analogue problems plays a key role in the removal of dielectric singularities. We illustrate this approach by creating two designs of carpet cloak and a collimating lens as representative examples in two- and three-dimensional spaces, respectively. The analogy strategy not only reveals the intimate connections between different physical disciplines, such as optics, fluid mechanics and electrostatics, but also provides a heuristic pathway to designing advanced photonic systems

  12. Analog fault diagnosis by inverse problem technique

    KAUST Repository

    Ahmed, Rania F.


    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.

  13. Analogical Trust Reasoning (United States)

    Tavakolifard, Mozhgan; Herrmann, Peter; Öztürk, Pinar

    Trust is situation-specific and the trust judgment problem with which the truster is confronted might be, in some ways, similar but not identical to some problems the truster has previously encountered. The truster then may draw information from these past experiences useful for the current situation. We present a knowledge-intensive and model-based case-based reasoning framework that supports the truster to infer such information. The suggested method augments the typically sparse trust information by inferring the missing information from other situational conditions, and can better support situation-aware trust management. Our framework can be coupled with existing trust management models to make them situation-aware. It uses the underlying model of trust management to transfer trust information between situations. We validate the proposed framework for Subjective Logic trust management model and evaluate it by conducting experiments on a large real dataset.

  14. Analog electronics for radiation detection

    CERN Document Server


    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 ...

  15. Josephson junction analog and quasiparticle-pair current

    DEFF Research Database (Denmark)

    Bak, Christen Kjeldahl; Pedersen, Niels Falsig


    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...

  16. Fast parallel-series analog-to-digital converter

    International Nuclear Information System (INIS)

    Pogosov, A.Yu.


    Fast analog-to-digital converters are used in systems for detection of rapid processes, nuclear spectroscopy. A 12-digit analog-to-digital converter with conversion time of 160 ns and conversion frequency of 8.3 MHz is described; a segmented digital-to-analog converter with differential non-linearity of < 0.01% and a differential amplifier-limiter with setting time of 80 ns at the error of 0.2% are utilized in the converter; a control device is based on the chain of flip-flop circuit

  17. Generating explanations via analogical comparison. (United States)

    Hoyos, Christian; Gentner, Dedre


    Generating explanations can be highly effective in promoting learning in both adults and children. Our interest is in the mechanisms that underlie this effect and in whether and how they operate in early learning. In adult reasoning, explanation may call on many subprocesses-including comparison, counterfactual reasoning, and reasoning by exclusion; but it is unlikely that all these processes are available to young children. We propose that one process that may serve both children and adults is comparison. In this study, we asked whether children would use the results of a comparison experience when asked to explain why a model skyscraper was stable. We focused on a challenging principle-that diagonal cross-bracing lends stability to physical structures (Gentner et al., Cognitive Science, 40, 224-240, 2016). Six-year-olds either received no training or interacted with model skyscrapers in one of three different conditions, designed to vary in their potential to invite and support comparison. In the Single Model condition, children interacted with a single braced model. In the comparison conditions (Low Alignability and High Alignability), children compared braced and unbraced models. Following experience with the models, children were asked to explain why the braced model was stable. They then received two transfer tasks. We found that children who received highly alignable pairs were most likely to (a) produce brace-based explanations and (b) transfer the brace principle to a dissimilar context. This provides evidence that children can benefit from analogical comparison in generating explanations and also suggests limitations on this ability.

  18. 22nd Workshop on Advances in Analog Circuit Design

    CERN Document Server

    Makinwa, Kofi; Harpe, Pieter


    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.

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

    CERN Document Server

    Figueiredo, Michael; Evans, Guiomar


    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 ...


    DEFF Research Database (Denmark)

    Gaunholt, Hans


    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...

  1. Drawing Analogies to Deepen Learning (United States)

    Fava, Michelle


    This article offers examples of how drawing can facilitate thinking skills that promote analogical reasoning to enable deeper learning. The instructional design applies cognitive principles, briefly described here. The workshops were developed iteratively, through feedback from student and teacher participants. Elements of the UK National…

  2. CMOS Analog IC Design: Fundamentals

    DEFF Research Database (Denmark)

    Bruun, Erik

    This book is intended for use as the main textbook for an introductory course in CMOS analog integrated circuit design. It is aimed at electronics engineering students who have followed basic courses in mathematics, physics, circuit theory, electronics and signal processing. It takes the students...

  3. Paper Analogies Enhance Biology Teaching. (United States)

    Stencel, John E.


    Describes how to use paper analogies as models to illustrate various concepts in biology, human anatomy, and physiology classes. Models include biochemical paper models, protein papergrams, a paper model of early brain development, and a 3-D paper model of a eukaryotic cell. (AIM)

  4. Crows spontaneously exhibit analogical reasoning. (United States)

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward


    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. The use of analogy in pro-life argumentation

    Directory of Open Access Journals (Sweden)

    Simona Mazilu


    Full Text Available The paper is concerned with how analogy is strategically used in pro-life argumentation on abortion. Pragma-dialectics (van Eemeren and Grootendorst 1992 offers a set of critical questions by means of which I will evaluate the use of the argumentation based on a relation of analogy in terms of dialectical soundness. Examining various pro-life texts, I have noticed that the analogies employed remain unexplained. Therefore, despite the apparent similarities between abortion and the German holocaust or slavery, for instance, there are essential differences which are not mentioned. I claim that these analogies mainly have a rhetorical function, to operate what has been called by Micheli (2007: 960 “a transfer of emotional consensus”.

  6. The use of analogy in pro-life argumentation

    Directory of Open Access Journals (Sweden)

    Simona Mazilu


    Full Text Available The paper is concerned with how analogy is strategically used in pro-life argumentation on abortion. Pragma-dialectics (van Eemeren and Grootendorst 1992 offers a set of critical questions by means of which I will evaluate the use of the argumentation based on a relation of analogy in terms of dialectical soundness. Examining various pro-life texts, I have noticed that the analogies employed remain unexplained. Therefore, despite the apparent similarities between abortion and the German holocaust or slavery, for instance, there are essential differences which are not mentioned. I claim that these analogies mainly have a rhetorical function, to operate what has been called by Micheli (2007: 960 “a transfer of emotional consensus”.

  7. Leibniz y el concepto de analogía

    Directory of Open Access Journals (Sweden)

    Oscar Miguel Esquisabel


    Full Text Available In this paper an analysis of the leibnizian applications of conceptof analogy as well as the analogical reasoning is approached. Thus, the analysis tries to show that the leibnizian concept of analogy is based on the idea of structural similarity. As a consequence of such consideration,two basic ways in which Leibniz applies analogical reasoning are examined. The first way has a conjectural character and is rather heuristic, whereas the second constitutes, at least in intention, a kind of demonstrative analogicalreasoning, since it tries to prove its conclusions for a determined theoreticaldomain by applying a transfer principle, which is itself founded on the identity of structural properties.This procedure is exemplified by outlining the leibnizian view on contingent truths. In this way, the paper concludesby pointing out the theoretical relevance of the concept of similarity in theleibnizian thought.

  8. Analog circuit design art, science and personalities

    CERN Document Server

    Williams, Jim


    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

  9. A direct method for the identification of the permeability field based on flux assimilation by a discrete analog of Darcy's law

    NARCIS (Netherlands)

    Zijl, W.


    Inverse models to determine the permeability are generally based on existing forward models for the pressure. The permeabilities are adapted in such a way that the calculated pressures match the specified pressures in a number of points. To assimilate a priori knowledge about the flux, we introduce

  10. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel


    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...

  11. Novel phosphanucleoside analogs of dideoxynucleosides

    Czech Academy of Sciences Publication Activity Database

    Páv, Ondřej; Buděšínský, Miloš; Rosenberg, Ivan


    Roč. 73, č. 34 (2017), s. 5220-5228 ISSN 0040-4020 R&D Projects: GA ČR(CZ) GA17-12703S; GA ČR GA13-26526S; GA MZd NV15-31604A Institutional support: RVO:61388963 Keywords : phosphanucleoside * nucleoside analog * ring-closing metathesis * stereoselective hydroboration * chiral resolution Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 2.651, year: 2016

  12. Cross Domain Analogies for Learning Domain Theories

    National Research Council Canada - National Science Library

    Klenk, Matthew; Forbus, Ken


    .... This work describes a method for learning new domain theories by analogy. We use analogies between pairs of problems and worked solutions to create a domain mapping between a familiar and a new domain...

  13. The Development of Analogical Reasoning Processes. (United States)

    Sternberg, Robert J.; Rifkin, Bathsheva


    Two experiments were conducted to test the generalizability to children of a theory of analogical reasoning processes, originally proposed for adults, and to examine the development of analogical reasoning processes in terms of five proposed sources of cognitive development. (MP)

  14. Peptide receptor radionuclide therapy of Merkel cell carcinoma using (177)lutetium-labeled somatostatin analogs in combination with radiosensitizing chemotherapy: a potential novel treatment based on molecular pathology. (United States)

    Salavati, Ali; Prasad, Vikas; Schneider, Claus-Peter; Herbst, Rudolf; Baum, Richard Paul


    Few studies have been published on the safety and feasibility of synchronous use of peptide receptor radionuclide therapy (PRRNT), as source of internal radiation therapy, in combination with chemotherapy. In this study we reported a 53-year-old man with stage IV Merkel cell carcinoma (MCC), who underwent synchronous internal radiation therapy and chemotherapy. Based on presumable poor prognosis with chemotherapy only, functional similarities of MCC with other neuroendocrine tumors and available evidence of effectiveness and safety of synchronous use of external beam radiation therapy and chemotherapy in treatment of high-risk MCC patients, our interdisciplinary neuroendocrine tumor board recommended him to add PRRNT to his ongoing chemotherapy. He received 2 courses of (177)Lu-DOTATATE(1, 4, 7, 10-Tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid-1-D-Phe1-Tyr3-Thr8-octreotide) in combination with ongoing 8 cycles of liposomal doxorubicin based on standard protocols. Response to therapy was evaluated by (18)F-FDG and (68)gallium-somatostatin-receptor PET/CT. There was an impressive improvement of the clinical symptoms. However, follow-up PET/CT studies showed mixed pattern of response. Synchronous use of PRRNT and radiosensitizing chemotherapy seems safe and feasible in high risk MCC patients, however, further prospective studies and clinical trials are warranted to provide reliable evidence of possible pitfalls and effectiveness of PRRNT and (68)Ga-somatostatin-receptor PET/CT in the management of MCC.

  15. Hegel, Analogy, and Extraterrestrial Life (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

  16. Fast event recorder utilizing a CCD analog shift register

    International Nuclear Information System (INIS)

    Ducar, R.J.; McIntyre, P.M.


    A system of electronics has been developed to allow the capture and recording of relatively fast, low-amplitude analog events. The heart of the system is a dual 455-cell analog shift register charge-coupled device, Fairchild CCD321ADC-3. The CCD is operated in a dual clock mode. The input is sampled at a selectable clock rate of .25-20 MHz. The stored analog data is then clocked out at a slower rate, typically about .25 MHz. The time base expansion of the analog data allows for analog-to-digital conversion and memory storage using conventional medium-speed devices. The digital data is sequentially loaded into a static RAM and may then be block transferred to a computer. The analog electronics are housed in a single-width NIM module, and the RAM memory in a single-width CAMAC module. Each pair of modules provides six parallel channels. Cost is about $200.00 per channel. Applications are described for ionization imaging (TPC, IRC) and long-drift calorimetry in liquid argon

  17. Science Teachers' Analogical Reasoning (United States)

    Mozzer, Nilmara Braga; Justi, Rosária


    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to…

  18. The Micro-Category Account of Analogy (United States)

    Green, Adam E.; Fugelsang, Jonathan A.; Kraemer, David J. M.; Dunbar, Kevin N.


    Here, we investigate how activation of mental representations of categories during analogical reasoning influences subsequent cognitive processing. Specifically, we present and test the central predictions of the "Micro-Category" account of analogy. This account emphasizes the role of categories in aligning terms for analogical mapping. In a…

  19. The analog computation and contrast test of leaked electromagnetic noise in the klystron corridor

    International Nuclear Information System (INIS)

    Tao Xiaoping; Wang Guicheng


    In order to obtain a better understand of the characteristics and location of noise source, the leaked electromagnetic noise in the klystron corridor of NSRL has been analogously calculated. The computational method and formula of high frequency leaked noise of the modulator were given. On-the-spot contrast tests have been made on the base of analog computation. The contrast test results show reasonableness of analog computation and whereby offer a theoretic base for reducing noise leakage in corridor

  20. CT-Based Anatomical Evaluation of Pre-Vertebral Structures With Respect to Vertebral Body Using a Clock-Face Analogy. (United States)

    Sarwahi, Vishal; Gecelter, Rachel C; Wendolowski, Stephen F; Kulkarni, Preethi M; Wang, Dan; Amaral, Terry D; Thornhill, Beverly


    Retrospective Chart and CT Scan Review. To define the relationship of the pre-vertebral structures for each level to assist in easier intraoperative visualization. Vascular and visceral injuries from pedicle screws are well-known. This study will define the relationship of the pre-vertebral structures for each level to assist in avoiding potential complications. Pre- and post-operative CT scans were reviewed to define the pre-vertebral structures in relation to a clock-face. On reformatted axial slices, a clock-face was superimposed so that the left transverse process (TP) represented 8 o'clock and the right TP represented 4 o'clock. The positions of the TP on the clock-face did not change with rotation of the vertebra. 108 patients had pre-operative CT scans. 78 had post-operative CT scans. Median age was 15 years, median Cobb angle was 50°, fused were 12, with 21 fixation points. 6324 axial CT slices were reformatted and analyzed. The trachea was located at 12 o'clock at T1, 1 o'clock at T2-T4, and between 12 and 1 o'clock at T5. The esophagus starts as a midline structure at 12 o'clock from T1-T2, moves to 11 o'clock from T3-T6, and further to 10 o'clock from T7-T9. The aorta starts at 10 o'clock at T5-T6, moves left at T7-T8 to 9 o'clock, and returns to 10 o'clock from T9-T11. It appears at 11'clock at T12, and at 12 o'clock from L1-L4. In about a third of cases, it is at 1 o'clock from L1 to L4, where it bifurcates. This CT-based anatomical study provides a simple reference frame to help surgeons visualize the vital structures at each level. This three-dimensional visualization is facilitated by fixing the position of TP on the clock-face. Knowledge of this anatomical relationship can help avoid direct injury, and is easier to recall intra-operatively. 3.

  1. Resistive RAMs as analog trimming elements (United States)

    Aziza, H.; Perez, A.; Portal, J. M.


    This work investigates the use of Resistive Random Access Memory (RRAM) as an analog trimming device. The analog storage feature of the RRAM cell is evaluated and the ability of the RRAM to hold several resistance states is exploited to propose analog trim elements. To modulate the memory cell resistance, a series of short programming pulses are applied across the RRAM cell allowing a fine calibration of the RRAM resistance. The RRAM non volatility feature makes the analog device powers up already calibrated for the system in which the analog trimmed structure is embedded. To validate the concept, a test structure consisting of a voltage reference is evaluated.

  2. Analog and mixed-signal electronics

    CERN Document Server

    Stephan, Karl


    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

  3. Analog circuit design art, science, and personalities

    CERN Document Server

    Williams, Jim


    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

  4. Practical analog electronics for technicians

    CERN Document Server

    Kimber, W A


    '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

  5. Reliability of analog quantum simulation

    Energy Technology Data Exchange (ETDEWEB)

    Sarovar, Mohan [Sandia National Laboratories, Digital and Quantum Information Systems, Livermore, CA (United States); Zhang, Jun; Zeng, Lishan [Shanghai Jiao Tong University, Joint Institute of UMich-SJTU, Key Laboratory of System Control and Information Processing (MOE), Shanghai (China)


    Analog quantum simulators (AQS) will likely be the first nontrivial application of quantum technology for predictive simulation. However, there remain questions regarding the degree of confidence that can be placed in the results of AQS since they do not naturally incorporate error correction. Specifically, how do we know whether an analog simulation of a quantum model will produce predictions that agree with the ideal model in the presence of inevitable imperfections? At the same time there is a widely held expectation that certain quantum simulation questions will be robust to errors and perturbations in the underlying hardware. Resolving these two points of view is a critical step in making the most of this promising technology. In this work we formalize the notion of AQS reliability by determining sensitivity of AQS outputs to underlying parameters, and formulate conditions for robust simulation. Our approach naturally reveals the importance of model symmetries in dictating the robust properties. To demonstrate the approach, we characterize the robust features of a variety of quantum many-body models. (orig.)

  6. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J. M


    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...

  7. Analogical reasoning in schizophrenic delusions. (United States)

    Simpson, Jane; Done, D John


    Reasoning ability has often been argued to be impaired in people with schizophrenic delusions, although evidence for this is far from convincing. This experiment examined the analogical reasoning abilities of several groups of patients, including non-deluded and deluded schizophrenics, to test the hypothesis that performance by the deluded schizophrenic group would be impaired. Eleven deluded schizophrenics, 10 depressed subjects, seven non-deluded schizophrenics and 16 matched non-psychiatric controls, who were matched on a number of key variables, were asked to solve an analogical reasoning task. Performance by the deluded schizophrenic group was certainly impaired when compared with the depressed and non-psychiatric control groups though less convincingly so when compared with the non-deluded schizophrenic group. The impairment shown by the deluded schizophrenic group seemed to occur at the initial stage of the reasoning task. The particular type of impairment shown by the deluded subjects was assessed in relation to other cognitive problems already researched and the implications of these problems on reasoning tasks and theories of delusions was discussed.

  8. High school biology students' participation in a year-long sequence of analogical activities: The relationship of development of analogical thought to student learning and classroom interactions (United States)

    Hackney, Marcella Wichser


    This research explored development of analogical thought through high school biology students' participation in a year-long sequence of analogical activities. Analogizing involves: selecting a familiar analog; mapping similarities and differences between the analog and less familiar target; making inferences from the analogy; evaluating validity of the inferences; and ultimately, understanding the biological target (Holyoak & Thagard, 1995). This investigation considered: student development of independence in learning through analogical thought, student learning of biology, the relationship between development of students' analogical thinking and students' learning of biology, and the quality of student interactions in the classroom This researcher, as teacher participant, used three approaches for teaching by analogy: traditional didactic, teacher-guided, and analogy-generated-by-the-student (Zeitoun, 1983). Within cooperative groups, students in one honors biology class actively engaged in research-based analogical activities that targeted specific biological topics. Two honors biology classes participated in similar, but nonanalogical activities that targeted the same biological topics. This two-class comparison group permitted analytical separation of effects of the analogical emphasis from the effects of biology content and activity-based learning. Data collected included: fieldnotes of researcher observations, student responses to guidesheets, tapes of group interactions, student products, student perceptions survey evaluations, ratings of students' expressed analogical development, pre- and posttest scores on a biology achievement test, essay responses, and selected student interviews. These data formed the basis for researcher qualitative analysis, augmented by quantitative techniques. Through participation in the sequence of analogical activities, students developed their abilities to engage in the processes of analogical thinking, but attained different

  9. A Computer-Based Visual Analog Scale, (United States)


    sensitive, reliable, and valid indices of pain sensations (6- 8). The patient places a mark on a line between two extremes correspoi (ding to the level of...3. Menkes, D.B., Howard, R.C., Spears, G.F., and Cairns, E.R., "Salivary THC Following Cannabis Smoking Correlates With Subjective Intoxication and...Simpson, MA., Schoeman, H.S. & Alman, BJ., "A Profile of Buspirone in the Treatment of Anxiety in General Practice Patients." Current Therapeutic

  10. Operational Lessons Learned from NASA Analog Missions (United States)

    Arnold, Larissa S.


    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.

  11. Automatic activation of categorical and abstract analogical relations in analogical reasoning. (United States)

    Green, Adam E; Fugelsang, Jonathan A; Dunbar, Kevin N


    We examined activation of concepts during analogical reasoning. Subjects made either analogical judgments or categorical judgments about four-word sets. After each four-word set, they named the ink color of a single word in a modified Stroop task. Words that referred to category relations were primed (as indicated by longer response times on Stroop color naming) subsequent to analogical judgments and categorical judgments. This finding suggests that activation of category concepts plays a fundamental role in analogical thinking. When colored words referred to analogical relations, priming occurred subsequent to analogical judgments, but not to categorical judgments, even though identical four-word stimuli were used for both types of judgments. This finding lends empirical support to the hypothesis that, when people comprehend the analogy between two items, they activate an abstract analogical relation that is distinct from the specific content items that compose the analogy.

  12. In silico design and screening of hypothetical MOF-74 analogs and their experimental synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Witman, Matthew [Department of Chemical and Biomolecular Engineering; University of California; Berkeley 94720; USA; Ling, Sanliang [Department of Chemistry; University College London; London WC1H 0AJ; UK; Anderson, Samantha [Laboratory of Molecular Simulation; Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); CH-1951 Sion; Switzerland; Tong, Lianheng [Department of Physics; King' s College London; London; UK; Stylianou, Kyriakos C. [Laboratory of Molecular Simulation; Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); CH-1951 Sion; Switzerland; Slater, Ben [Department of Chemistry; University College London; London WC1H 0AJ; UK; Smit, Berend [Department of Chemical and Biomolecular Engineering; University of California; Berkeley 94720; USA; Laboratory of Molecular Simulation; Haranczyk, Maciej [Computational Research Division; Lawrence Berkeley National Laboratory; Berkeley; USA; IMDEA Materials Institute


    We present thein silico designof MOFs exhibiting 1-dimensional rod topologies by enumerating MOF-74-type analogs based on the PubChem Compounds database. We simulate the adsorption behavior of CO2in the generated analogs and experimentally validate a novel MOF-74 analog, Mg2(olsalazine).

  13. Development of a Cell-Based Fluorescence Resonance Energy Transfer Reporter for Bacillus anthracis Lethal Factor Protease

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, R H; Steenblock, E R; Camarero, J A


    We report the construction of a cell-based fluorescent reporter for anthrax lethal factor (LF) protease activity using the principle of fluorescence resonance energy transfer (FRET). This was accomplished by engineering an Escherichia coli cell line to express a genetically encoded FRET reporter and LF protease. Both proteins were encoded in two different expression plasmids under the control of different tightly controlled inducible promoters. The FRET-based reporter was designed to contain a LF recognition sequence flanked by the FRET pair formed by CyPet and YPet fluorescent proteins. The length of the linker between both fluorescent proteins was optimized using a flexible peptide linker containing several Gly-Gly-Ser repeats. Our results indicate that this FRET-based LF reporter was readily expressed in E. coli cells showing high levels of FRET in vivo in the absence of LF. The FRET signal, however, decreased 5 times after inducing LF expression in the same cell. These results suggest that this cell-based LF FRET reporter may be used to screen genetically encoded libraries in vivo against LF.

  14. An emergent approach to analogical inference (United States)

    Thibodeau, Paul H.; Flusberg, Stephen J.; Glick, Jeremy J.; Sternberg, Daniel A.


    In recent years, a growing number of researchers have proposed that analogy is a core component of human cognition. According to the dominant theoretical viewpoint, analogical reasoning requires a specific suite of cognitive machinery, including explicitly coded symbolic representations and a mapping or binding mechanism that operates over these representations. Here we offer an alternative approach: we find that analogical inference can emerge naturally and spontaneously from a relatively simple, error-driven learning mechanism without the need to posit any additional analogy-specific machinery. The results also parallel findings from the developmental literature on analogy, demonstrating a shift from an initial reliance on surface feature similarity to the use of relational similarity later in training. Variants of the model allow us to consider and rule out alternative accounts of its performance. We conclude by discussing how these findings can potentially refine our understanding of the processes that are required to perform analogical inference.

  15. Analogical processes in children's understanding of spatial representations. (United States)

    Yuan, Lei; Uttal, David; Gentner, Dedre


    We propose that map reading can be construed as a form of analogical mapping. We tested 2 predictions that follow from this claim: First, young children's patterns of performance in map reading tasks should parallel those found in analogical mapping tasks; and, second, children will benefit from guided alignment instructions that help them see the relational correspondences between the map and the space. In 4 experiments, 3-year-olds completed a map reading task in which they were asked to find hidden objects in a miniature room, using a corresponding map. We manipulated the availability of guided alignment (showing children the analogical mapping between maps and spaces; Experiments 1, 2, and 3a), the format of guided alignment (gesture or relational language; Experiment 2), and the iconicity of maps (Experiments 3a and 3b). We found that (a) young children's difficulties in map reading follow from known patterns of analogical development-for example, focusing on object similarity over relational similarity; and (b) guided alignment based on analogical reasoning led to substantially better performance. Results also indicated that children's map reading performance was affected by the format of guided alignment, the iconicity of the maps, and the order of tasks. The results bear on the developmental mechanisms underlying young children's learning of spatial representations and also suggest ways to support this learning. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. Specialization of the Rostral Prefrontal Cortex for Distinct Analogy Processes (United States)

    Gilbert, Sam J.; Benoit, Roland G.; Burgess, Paul W.


    Analogical reasoning is central to learning and abstract thinking. It involves using a more familiar situation (source) to make inferences about a less familiar situation (target). According to the predominant cognitive models, analogical reasoning includes 1) generation of structured mental representations and 2) mapping based on structural similarities between them. This study used functional magnetic resonance imaging to specify the role of rostral prefrontal cortex (PFC) in these distinct processes. An experimental paradigm was designed that enabled differentiation between these processes, by temporal separation of the presentation of the source and the target. Within rostral PFC, a lateral subregion was activated by analogy task both during study of the source (before the source could be compared with a target) and when the target appeared. This may suggest that this subregion supports fundamental analogy processes such as generating structured representations of stimuli but is not specific to one particular processing stage. By contrast, a dorsomedial subregion of rostral PFC showed an interaction between task (analogy vs. control) and period (more activated when the target appeared). We propose that this region is involved in comparison or mapping processes. These results add to the growing evidence for functional differentiation between rostral PFC subregions. PMID:20156841

  17. Silicon analog components device design, process integration, characterization, and reliability

    CERN Document Server

    El-Kareh, Badih


    This book covers modern analog components, their characteristics, and interactions with process parameters. It serves as a comprehensive guide, addressing both the theoretical and practical aspects of modern silicon devices and the relationship between their electrical properties and processing conditions. Based on the authors’ extensive experience in the development of analog devices, this book is intended for engineers and scientists in semiconductor research, development and manufacturing. The problems at the end of each chapter and the numerous charts, figures and tables also make it appropriate for use as a text in graduate and advanced undergraduate courses in electrical engineering and materials science.

  18. The use of Antarctic analogs for the Space Exploration Initiative (United States)

    Roberts, Barney; Lynch, John T.


    Potential approaches to the use of the Antarctic as an analog to the lunar and Mars planetary surface segments of the SEI are reviewed. It is concluded that a well-planned and sustained program of ground-based research and testing in environments analogous to the moon and Mars is a rational method for reducing the risks associated with human space missions. Antarctica may provide an ideal setting for testing critical technologies (habitat design, life support, and advanced scientific instrumentation), studying human factors and physiology, and conducting basic scientific research similar to and directly relevant to that planned for the SEI.

  19. Large-scale digitizer system, analog converters

    International Nuclear Information System (INIS)

    Althaus, R.F.; Lee, K.L.; Kirsten, F.A.; Wagner, L.J.


    Analog to digital converter circuits that are based on the sharing of common resources, including those which are critical to the linearity and stability of the individual channels, are described. Simplicity of circuit composition is valued over other more costly approaches. These are intended to be applied in a large-scale processing and digitizing system for use with high-energy physics detectors such as drift-chambers or phototube-scintillator arrays. Signal distribution techniques are of paramount importance in maintaining adequate signal-to-noise ratio. Noise in both amplitude and time-jitter senses is held sufficiently low so that conversions with 10-bit charge resolution and 12-bit time resolution are achieved

  20. Nilpotent Quantum Mechanics: Analogs and Applications

    Directory of Open Access Journals (Sweden)

    Peter Marcer


    Full Text Available The most significant characteristic of nilpotent quantum mechanics is that the quantum system (fermion state and its environment (vacuum are, in mathematical terms, mirror images of each other. So a change in one automatically leads to corresponding changes in the other. We have used this characteristic as a model for self-organization, which has applications well beyond quantum physics. The nilpotent structure has also been identified as being constructed from two commutative vector spaces. This zero square-root construction has a number of identifiable characteristics which we can expect to find in systems where self-organization is dominant, and a case presented after the publication of a paper by us on “The ‘Logic’ of Self-Organizing Systems” [1], in the organization of the neurons in the visual cortex. We expect to find many more complex systems where our general principles, based, by analogy, on nilpotent quantum mechanics, will apply.

  1. Holographic brain: a good analogy gone bad (United States)

    Caulfield, H. John


    One way of honoring the world's two greatest holographers is to remove from their field the association with the offbeat world of the holographic mind. Basing itself on analogical musings of two very creative scientists who were themselves not holographers, this 'field' of the holographic brain has strayed far from science and into the absurd. So much absurdity has been written by so many people that the one legitimate study of holographic principle in dolphins has been grouped too often with the nonsense. Here is taken most of the 'target statements' form one book. We could not bear to read them all this closely. We will attempt to determine what tidbit of fact led to the statements and to suggest alternative explanations when there is something to explain.

  2. On analog implementations of discrete neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.; Moore, K.R.


    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.

  3. Resizing methodology for CMOS analog circuits (United States)

    Levi, Timothée; Tomas, Jean; Lewis, Noëlle; Fouillat, Pascal


    This paper proposes a CMOS resizing methodology for analog circuits during a technology migration. The scaling rules aim to be easy to apply and are based on the simplest MOS transistor model. The principle is to transpose one circuit topology from one technology to another, while keeping the main figures of merit, and the issue is to quickly calculate the new transistor dimensions. Furthermore, when the target technology has smaller minimum length, we expect to obtain a decrease of area. This methodology is applied to both linear and non-linear examples: an OTA and a ring oscillator. The results are compared on three CMOS processes whose minimum length is 0.8 μm, 0.35 μm, 0.25 μm.

  4. Properties of compressible elastica from relativistic analogy. (United States)

    Oshri, Oz; Diamant, Haim


    Kirchhoff's kinetic analogy relates the deformation of an incompressible elastic rod to the classical dynamics of rigid body rotation. We extend the analogy to compressible filaments and find that the extension is similar to the introduction of relativistic effects into the dynamical system. The extended analogy reveals a surprising symmetry in the deformations of compressible elastica. In addition, we use known results for the buckling of compressible elastica to derive the explicit solution for the motion of a relativistic nonlinear pendulum. We discuss cases where the extended Kirchhoff analogy may be useful for the study of other soft matter systems.

  5. Relations as transformations: implications for analogical reasoning. (United States)

    Leech, Robert; Mareschal, Denis; Cooper, Richard P


    We present two experiments assessing whether the size of a transformation instantiating a relation between two states of the world (e.g., shrinks) is a performance factor affecting analogical reasoning. The first experiment finds evidence of transformation size as a significant factor in adolescent analogical problem solving while the second experiment finds a similar effect on adult analogical reasoning using a markedly different analogical completion paradigm. The results are interpreted as providing evidence for the more general framework that cognitive representations of relations are best understood as mental transformations.


    National Aeronautics and Space Administration — The OLS Analog Derived Lightning dataset consists of global lightning signatures from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System...

  7. Curriculum and Law: An Elaboration of the Analogy. (United States)

    Orpwood, Graham W. F.

    A new conceptualization of the curriculum field is offered that is based on an analogy with the field of law. The conceptualization is able to account for the existence in curriculum of a variety of differing normative curriculum theories. Two theories of law (natural law and legal positivism) are described and shown to have exact counterparts in…

  8. Decay Properties Of The Dipole Isobaric Analog Resonances

    NARCIS (Netherlands)

    Gorelik, M. L.; Safonov, I. V.; Urin, M. H.


    Abstract: A continuum-RPA-based approach is applied to describe the decay properties of isolated dipole isobaric analog resonances in nuclei having not-too-large neutron excess. Calculated for a few resonances in 90Zr the elastic E1-radiative width and partial proton widths for decay into one-hole

  9. A CMOS four-quadrant analog current multiplier

    NARCIS (Netherlands)

    Wiegerink, Remco J.


    A CMOS four-quadrant analog current multiplier is described. The circuit is based on the square-law characteristic of an MOS transistor and is insensitive to temperature and process variations. The circuit is insensitive to the body effect so it is not necessary to place transistors in individual

  10. Methodology for the digital calibration of analog circuits and systems with case studies

    CERN Document Server

    Pastre, Marc


    Methodology for the Digital Calibration of Analog Circuits and Systems shows how to relax the extreme design constraints in analog circuits, allowing the realization of high-precision systems even with low-performance components. A complete methodology is proposed, and three applications are detailed. To start with, an in-depth analysis of existing compensation techniques for analog circuit imperfections is carried out. The M/2+M sub-binary digital-to-analog converter is thoroughly studied, and the use of this very low-area circuit in conjunction with a successive approximations algorithm for digital compensation is described. A complete methodology based on this compensation circuit and algorithm is then proposed. The detection and correction of analog circuit imperfections is studied, and a simulation tool allowing the transparent simulation of analog circuits with automatic compensation blocks is introduced. The first application shows how the sub-binary M/2+M structure can be employed as a conventional di...

  11. FRET-based modified graphene quantum dots for direct trypsin quantification in urine

    Energy Technology Data Exchange (ETDEWEB)

    Poon, Chung-Yan; Li, Qinghua [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region (Hong Kong); Zhang, Jiali; Li, Zhongping [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region (Hong Kong); Research Center of Environmental Science and Engineering, School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China); Dong, Chuan [Research Center of Environmental Science and Engineering, School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China); Lee, Albert Wai-Ming; Chan, Wing-Hong [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region (Hong Kong); Li, Hung-Wing, E-mail: [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region (Hong Kong)


    A versatile nanoprobe was developed for trypsin quantification with fluorescence resonance energy transfer (FRET). Here, fluorescence graphene quantum dot is utilized as a donor while a well-designed coumarin derivative, CMR2, as an acceptor. Moreover, bovine serum albumin (BSA), as a protein model, is not only served as a linker for the FRET pair, but also a fluorescence enhancer of the quantum dots and CMR2. In the presence of trypsin, the FRET system would be destroyed when the BSA is digested by trypsin. Thus, the emission peak of the donor is regenerated and the ratio of emission peak of donor/emission peak of acceptor increased. By the ratiometric measurement of these two emission peaks, trypsin content could be determined. The detection limit of trypsin was found to be 0.7 μg/mL, which is 0.008-fold of the average trypsin level in acute pancreatitis patient's urine suggesting a high potential for fast and low cost clinical screening. - Highlights: • A FRET-based biosensor was developed for direct quantification of trypsin. • Fast and sensitive screening of pancreatic disease was facilitated. • The direct quantification of trypsin in urine samples was demonstrated.

  12. Exploration of genetically encoded voltage indicators based on a chimeric voltage sensing domain

    Directory of Open Access Journals (Sweden)

    Yukiko eMishina


    Full Text Available Deciphering how the brain generates cognitive function from patterns of electrical signals is one of the ultimate challenges in neuroscience. To this end, it would be highly desirable to monitor the activities of very large numbers of neurons while an animal engages in complex behaviours. Optical imaging of electrical activity using genetically encoded voltage indicators (GEVIs has the potential to meet this challenge. Currently prevalent GEVIs are based on the voltage-sensitive fluorescent protein (VSFP prototypical design or on the voltage dependent state transitions of microbial opsins.We recently introduced a new VSFP design in which the voltage-sensing domain (VSD is sandwiched between a FRET pair of fluorescent proteins (termed VSFP-Butterflies and also demonstrated a series of chimeric VSD in which portions of the VSD of Ciona intestinalis voltage-sensitive phosphatase (Ci-VSP are substituted by homologous portions of a voltage-gated potassium channel subunit. These chimeric VSD had faster sensing kinetics than that of the native Ci-VSD. Here, we describe a new set of VSFPs that combine chimeric VSD with the Butterfly structure. We show that these chimeric VSFP-Butterflies can report membrane voltage oscillations of up to 200 Hz in cultured cells and report sensory evoked cortical population responses in living mice. This class of GEVIs may be suitable for imaging of brain rhythms in behaving mammalians.

  13. Los pasiegos. La analogía salvaje y lo salvaje de la analogía

    Directory of Open Access Journals (Sweden)



    -entendiendo salvaje como un pensamiento humano prístino-: por un lado en sus relaciones con el racionalismo (¿emerge la analogía desde el racionalismo?, ¿qué relación guarda con éste?, ¿su nacimiento es resultado de una función «natural»? y por otro sobre la naturaleza social de lo salvaje a partir de las bases sociales que lo producen. Es decir, se rastrea lo que de salvaje tiene la analogía, si la analogía es o no una función ahistórica y asocial del intelecto humano. No se examina todo el complejo analógico de los pasiegos, únicamente aquél que establece relaciones homólogas entre las vacas y el entorno.

  14. Expert analogy use in a naturalistic setting (United States)

    Kretz, Donald R.; Krawczyk, Daniel C.


    The use of analogy is an important component of human cognition. The type of analogy we produce and communicate depends heavily on a number of factors, such as the setting, the level of domain expertise present, and the speaker's goal or intent. In this observational study, we recorded economics experts during scientific discussion and examined the categorical distance and structural depth of the analogies they produced. We also sought to characterize the purpose of the analogies that were generated. Our results supported previous conclusions about the infrequency of superficial similarity in subject-generated analogs, but also showed that distance and depth characteristics were more evenly balanced than in previous observational studies. This finding was likely due to the nature of the goals of the participants, as well as the broader nature of their expertise. An analysis of analogical purpose indicated that the generation of concrete source examples of more general target concepts was most prevalent. We also noted frequent instances of analogies intended to form visual images of source concepts. Other common purposes for analogies were the addition of colorful speech, inclusion (i.e., subsumption) of a target into a source concept, or differentiation between source and target concepts. We found no association between depth and either of the other two characteristics, but our findings suggest a relationship between purpose and distance; i.e., that visual imagery typically entailed an outside-domain source whereas exemplification was most frequently accomplished using within-domain analogies. Overall, we observed a rich and diverse set of spontaneously produced analogical comparisons. The high degree of expertise within the observed group along with the richly comparative nature of the economics discipline likely contributed to this analogical abundance. PMID:25505437

  15. Expert Analogy Use in a Naturalistic Setting

    Directory of Open Access Journals (Sweden)

    Donald R Kretz


    Full Text Available The use of analogy is an important component of human cognition. The type of analogy we produce and communicate depends heavily on a number of factors, such as the setting, the level of domain expertise present, and the speaker’s goal or intent. In this observational study, we recorded economics experts during scientific discussion and examined the categorical distance and structural depth of the analogies they produced. We also sought to characterize the purpose of the analogies that were generated. Our results supported previous conclusions about the infrequency of superficial similarity in subject-generated analogs, but also showed that distance and depth characteristics were more evenly balanced than in previous observational studies. This finding was likely due to the nature of the goals of the participants, as well as the broader nature of their expertise. An analysis of analogical purpose indicated that the generation of concrete source examples of more general target concepts was most prevalent. We also noted frequent instances of analogies intended to form visual images of source concepts. Other common purposes for analogies were the addition of colorful speech, inclusion (i.e., subsumption of a target into a source concept, or differentiation between source and target concepts. We found no association between depth and either of the other two characteristics, but our findings suggest a relationship between purpose and distance; i.e., that visual imagery typically entailed an outside-domain source whereas exemplification was most frequently accomplished using within-domain analogies. Overall, we observed a rich and diverse set of spontaneously produced analogical comparisons. The high degree of expertise within the observed group along with the richly comparative nature of the economics discipline likely contributed to this analogical abundance.

  16. Single Cell FRET Analysis for the Identification of Optimal FRET-Pairs in Bacillus subtilis Using a Prototype MEM-FLIM System

    NARCIS (Netherlands)

    Detert Oude Weme, Ruud G J; Kovács, Ákos T; de Jong, Sander J G; Veening, Jan-Willem; Siebring, Jeroen; Kuipers, Oscar P


    Protein-protein interactions can be studied in vitro, e.g. with bacterial or yeast two-hybrid systems or surface plasmon resonance. In contrast to in vitro techniques, in vivo studies of protein-protein interactions allow examination of spatial and temporal behavior of such interactions in their

  17. High quality digital holographic reconstruction on analog film (United States)

    Nelsen, B.; Hartmann, P.


    High quality real-time digital holographic reconstruction, i.e. at 30 Hz frame rates, has been at the forefront of research and has been hailed as the holy grail of display systems. While these efforts have produced a fascinating array of computer algorithms and technology, many applications of reconstructing high quality digital holograms do not require such high frame rates. In fact, applications such as 3D holographic lithography even require a stationary mask. Typical devices used for digital hologram reconstruction are based on spatial-light-modulator technology and this technology is great for reconstructing arbitrary holograms on the fly; however, it lacks the high spatial resolution achievable by its analog counterpart, holographic film. Analog holographic film is therefore the method of choice for reconstructing highquality static holograms. The challenge lies in taking a static, high-quality digitally calculated hologram and effectively writing it to holographic film. We have developed a theoretical system based on a tunable phase plate, an intensity adjustable high-coherence laser and a slip-stick based piezo rotation stage to effectively produce a digitally calculated hologram on analog film. The configuration reproduces the individual components, both the amplitude and phase, of the hologram in the Fourier domain. These Fourier components are then individually written on the holographic film after interfering with a reference beam. The system is analogous to writing angularly multiplexed plane waves with individual component phase control.

  18. Novel Analog For Muscle Deconditioning (United States)

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


    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.

  19. Antibacterial and Antibiofilm Activities of Makaluvamine Analogs

    Directory of Open Access Journals (Sweden)

    Bhavitavya Nijampatnam


    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.


    Directory of Open Access Journals (Sweden)

    Nyoto Suseno


    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.

  1. Young Children's Analogical Reasoning in Science Domains (United States)

    Haglund, Jesper; Jeppsson, Fredrik; Andersson, Johanna


    This exploratory study in a classroom setting investigates first graders' (age 7-8 years, N = 25) ability to perform analogical reasoning and create their own analogies for two irreversible natural phenomena: mixing and heat transfer. We found that the children who contributed actively to a full-class discussion were consistently successful at…

  2. Children's Use of Analogy during Collaborative Reasoning (United States)

    Lin, Tzu-Jung; Anderson, Richard C.; Hummel, John E.; Jadallah, May; Miller, Brian W.; Nguyen-Jahiel, Kim; Morris, Joshua A.; Kuo, Li-Jen; Kim, Il-Hee; Wu, Xiaoying; Dong, Ting


    This microgenetic study examined social influences on children's development of analogical reasoning during peer-led small-group discussions of stories about controversial issues. A total of 277 analogies were identified among 7,215 child turns for speaking during 54 discussions from 18 discussion groups in 6 fourth-grade classrooms (N = 120; age…

  3. Patterns of Analogical Reasoning among Beginning Readers (United States)

    Farrington-Flint, Lee; Wood, Clare; Canobi, Katherine H.; Faulkner, Dorothy


    Despite compelling evidence that analogy skills are available to beginning readers, few studies have actually explored the possibility of identifying individual differences in young children's analogy skills in early reading. The present study examined individual differences in children's use of orthographic and phonological relations between…



    Haraguchi, Makoto; 原口, 誠


    A formalism of analogical reasoning is presented. The analogical reasoning can be considered as a deduction with a function of transforming logical rules. From this viewpoint, the reasoning is defined in terms of deduction, and is therefore realized in a logic programming system. The reasoning system is described as an extension of Prolog interpreter.

  5. An Analog Computer for Electronic Engineering Education (United States)

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


    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. A graphene quantum dot-based FRET system for nuclear-targeted and real-time monitoring of drug delivery. (United States)

    Chen, Hui; Wang, Zhuyuan; Zong, Shenfei; Chen, Peng; Zhu, Dan; Wu, Lei; Cui, Yiping


    A graphene quantum dot-based FRET system is demonstrated for nuclear-targeted drug delivery, which allows for real-time monitoring of the drug release process through FRET signals. In such a system, graphene quantum dots (GQDs) simultaneously serve as the carriers of drugs and donors of FRET pairs. Additionally, a peptide TAT as the nuclear localization signal is conjugated to GQDs, which facilitates the transportation of the delivery system to the nucleus. We have demonstrated that: (a) both the conjugated TAT and small size of GQDs contribute to targeting the nucleus, which results in a significantly enhanced intranuclear accumulation of drugs; (b) FRET signals being extremely sensitive to the distance between donors and acceptors are capable of real-time monitoring of the separation process of drugs and GQDs, which is more versatile in tracking the drug release dynamics. Our strategy for the assembly of a FRET-based drug delivery system may be unique and universal for monitoring the dynamic release process. This study may give more exciting new opportunities for improving the therapeutic efficacy and tracking precision.

  7. Transitioning from Analog to Digital Audio Recording in Childhood Speech Sound Disorders (United States)

    Shriberg, Lawrence D.; Mcsweeny, Jane L.; Anderson, Bruce E.; Campbell, Thomas F.; Chial, Michael R.; Green, Jordan R.; Hauner, Katherina K.; Moore, Christopher A.; Rusiewicz, Heather L.; Wilson, David L.


    Few empirical findings or technical guidelines are available on the current transition from analog to digital audio recording in childhood speech sound disorders. Of particular concern in the present context was whether a transition from analog- to digital-based transcription and coding of prosody and voice features might require re-standardizing…

  8. The Facilitatory Effect of Negative Feedback on the Emergence of Analogical Reasoning Abilities (United States)

    Ball, Linden J.; Hoyle, Alison M.; Towse, Andrea S.


    This paper focuses on the development of analogical reasoning abilities in 5- and 6-year-old children. Our particular interest relates to the way in which analogizing is influenced by the provision of task-based feedback coupled with a self-explanation requirement. Both feedback and self-explanation provide children with opportunities to engage in…

  9. Structure problems in the analog computation

    International Nuclear Information System (INIS)

    Braffort, P.L.


    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.)

  10. A dark business, full of shadows: analogy and theology in William Harvey. (United States)

    Goldberg, Benjamin


    In a short work called De conceptione appended to the end of his Exercitationes de generatione animalium (1651), William Harvey developed a rather strange analogy. To explain how such marvelous productions as living beings were generated from the rather inauspicious ingredients of animal reproduction, Harvey argued that conception in the womb was like conception in the brain. It was mostly rejected at the time; it now seems a ludicrous theory based upon homonymy. However, this analogy offers insight into the structure and function of analogies in early modern natural philosophy. In this essay I hope to not only describe the complex nature of Harvey's analogy, but also offer a novel interpretation of his use of analogical reasoning, substantially revising the account offered by Guido Giglioni (1993). I discuss two points of conceptual change and negotiation in connection with Harvey's analogy, understanding it as both a confrontation between the border of the natural and the supernatural, as well as a moment in the history of psychology. My interpretation touches upon a number of important aspects, including why the analogy was rejected, how Harvey systematically deployed analogies according to his notions of natural philosophical method, how the analogy fits into contemporary discussions of analogies in science, and finally, how the analogy must be seen in the context of changing Renaissance notions of the science of the soul, ultimately confronting the problem of how to understand final causality in Aristotelian science. In connection with the last, I conclude the essay by turning to how Harvey embeds the analogy within a natural theological cosmology. Copyright © 2013. Published by Elsevier Ltd.

  11. VME Switch for CERN's PS Analog Video System

    CERN Document Server

    Acebes, I; Heinze, W; Lewis, J; Serrano, J


    Analog video signal switching is used in CERN's Proton Synchrotron (PS) complex to route the video signals coming from Beam Diagnostics systems to the Meyrin Control Room (MCR). Traditionally, this has been done with custom electromechanical relay-based cards controlled serially via CAMAC crates. In order to improve the robustness and maintainability of the system, while keeping it analog to preserve the low latency, a VME card based on Analog Devices' AD8116 analog matrix chip has been developed. Video signals go into the front panel and exit the switch through the P2 connector of the VME backplane. The module is a 16 input, 32 output matrix. Larger matrices can be built using more modules and bussing their outputs together, thanks to the high impedance feature of the AD8116. Another VME module takes the selected signals from the P2 connector and performs automatic gain to send them at nominal output level through its front panel. This paper discusses both designs and presents experimental test results.

  12. Application of natural analog studies to exploration for ore deposits

    International Nuclear Information System (INIS)

    Gustafson, D.L.


    Natural analogs are viewed as similarities in nature and are routinely utilized by exploration geologists in their search for economic mineral deposits. Ore deposit modeling is undertaken by geologists to direct their exploration activities toward favorable geologic environments and, therefore, successful programs. Two types of modeling are presented: (i) empirical model development based on the study of known ore deposit characteristics, and (ii) concept model development based on theoretical considerations and field observations that suggest a new deposit type, not known to exist in nature, may exist and justifies an exploration program. Key elements that are important in empirical model development are described, and examples of successful applications of these natural analogs to exploration are presented. A classical example of successful concept model development, the discovery of the McLaughlin gold mine in California, is presented. The utilization of natural analogs is an important facet of mineral exploration. Natural analogs guide explorationists in their search for new discoveries, increase the probability of success, and may decrease overall exploration expenditure

  13. Semantics by analogy for illustrative volume visualization☆ (United States)

    Gerl, Moritz; Rautek, Peter; Isenberg, Tobias; Gröller, Eduard


    We present an interactive graphical approach for the explicit specification of semantics for volume visualization. This explicit and graphical specification of semantics for volumetric features allows us to visually assign meaning to both input and output parameters of the visualization mapping. This is in contrast to the implicit way of specifying semantics using transfer functions. In particular, we demonstrate how to realize a dynamic specification of semantics which allows to flexibly explore a wide range of mappings. Our approach is based on three concepts. First, we use semantic shader augmentation to automatically add rule-based rendering functionality to static visualization mappings in a shader program, while preserving the visual abstraction that the initial shader encodes. With this technique we extend recent developments that define a mapping between data attributes and visual attributes with rules, which are evaluated using fuzzy logic. Second, we let users define the semantics by analogy through brushing on renderings of the data attributes of interest. Third, the rules are specified graphically in an interface that provides visual clues for potential modifications. Together, the presented methods offer a high degree of freedom in the specification and exploration of rule-based mappings and avoid the limitations of a linguistic rule formulation. PMID:23576827

  14. Analog regulation of metabolic demand

    Directory of Open Access Journals (Sweden)

    Muskhelishvili Georgi


    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

  15. Assessment of Gate Width Size on Lifetime-Based Förster Resonance Energy Transfer Parameter Estimation

    Directory of Open Access Journals (Sweden)

    Sez-Jade Chen


    Full Text Available Förster Resonance Energy Transfer (FRET enables the observation of interactions at the nanoscale level through the use of fluorescence optical imaging techniques. In FRET, fluorescence lifetime imaging can be used to quantify the fluorescence lifetime changes of the donor molecule, which are associated with proximity between acceptor and donor molecules. Among the FRET parameters derived from fluorescence lifetime imaging, the percentage of donor that interacts with the acceptor (in proximity can be estimated via model-based fitting. However, estimation of the lifetime parameters can be affected by the acquisition parameters such as the temporal characteristics of the imaging system. Herein, we investigate the effect of various gate widths on the accuracy of estimation of FRET parameters with focus on the near-infrared spectral window. Experiments were performed in silico, in vitro, and in vivo with gate width sizes ranging from 300 ps to 1000 ps in intervals of 100 ps. For all cases, the FRET parameters were retrieved accurately and the imaging acquisition time was decreased three-fold. These results indicate that increasing the gate width up to 1000 ps still allows for accurate quantification of FRET interactions even in the case of short lifetimes such as those encountered with near-infrared FRET pairs.

  16. Nyquist AD Converters, Sensor Interfaces, and Robustness Advances in Analog Circuit Design, 2012

    CERN Document Server

    Baschirotto, Andrea; Steyaert, Michiel


    This book is based on the presentations during the 21st workshop on Advances in Analog Circuit Design.  Expert designers provide readers with information about a variety of topics at the frontier of analog circuit design, including Nyquist analog-to-digital converters, capacitive sensor interfaces, reliability, variability, and connectivity.  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 Nyquist A/D converters, capacitive sensor interfaces, reliability, variability, and connectivity.

  17. Frontopolar cortex mediates abstract integration in analogy. (United States)

    Green, Adam E; Fugelsang, Jonathan A; Kraemer, David J M; Shamosh, Noah A; Dunbar, Kevin N


    Integration of abstractly similar relations during analogical reasoning was investigated using functional magnetic resonance imaging. Activation elicited by an analogical reasoning task that required both complex working memory and integration of abstractly similar relations was compared to activation elicited by a non-analogical task that required complex working memory in the absence of abstract relational integration. A left-sided region of the frontal pole of the brain (BA 9/10) was selectively active for the abstract relational integration component of analogical reasoning. Analogical reasoning also engaged a left-sided network of parieto-frontal regions. Activity in this network during analogical reasoning is hypothesized to reflect categorical alignment of individual component terms that make up analogies. This parieto-frontal network was also engaged by the complex control task, which involved explicit categorization, but not by a simpler control task, which did not involve categorization. We hypothesize that frontopolar cortex mediates abstract relational integration in complex reasoning while parieto-frontal regions mediate working memory processes, including manipulation of terms for the purpose of categorical alignment, that facilitate this integration.

  18. Reasoning by analogy requires the left frontal pole: lesion-deficit mapping and clinical implications. (United States)

    Urbanski, Marika; Bréchemier, Marie-Laure; Garcin, Béatrice; Bendetowicz, David; Thiebaut de Schotten, Michel; Foulon, Chris; Rosso, Charlotte; Clarençon, Frédéric; Dupont, Sophie; Pradat-Diehl, Pascale; Labeyrie, Marc-Antoine; Levy, Richard; Volle, Emmanuelle


    SEE BURGESS DOI101093/BRAIN/AWW092 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE  : Analogical reasoning is at the core of the generalization and abstraction processes that enable concept formation and creativity. The impact of neurological diseases on analogical reasoning is poorly known, despite its importance in everyday life and in society. Neuroimaging studies of healthy subjects and the few studies that have been performed on patients have highlighted the importance of the prefrontal cortex in analogical reasoning. However, the critical cerebral bases for analogical reasoning deficits remain elusive. In the current study, we examined analogical reasoning abilities in 27 patients with focal damage in the frontal lobes and performed voxel-based lesion-behaviour mapping and tractography analyses to investigate the structures critical for analogical reasoning. The findings revealed that damage to the left rostrolateral prefrontal region (or some of its long-range connections) specifically impaired the ability to reason by analogies. A short version of the analogy task predicted the existence of a left rostrolateral prefrontal lesion with good accuracy. Experimental manipulations of the analogy tasks suggested that this region plays a role in relational matching or integration. The current lesion approach demonstrated that the left rostrolateral prefrontal region is a critical node in the analogy network. Our results also suggested that analogy tasks should be translated to clinical practice to refine the neuropsychological assessment of patients with frontal lobe lesions. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email:

  19. Analogical Argument Schemes and Complex Argument Structure

    Directory of Open Access Journals (Sweden)

    Andre Juthe


    Full Text Available This paper addresses several issues in argumentation theory. The over-arching goal is to discuss how a theory of analogical argument schemes fits the pragma-dialectical theory of argument schemes and argument structures, and how one should properly reconstruct both single and complex argumentation by analogy. I also propose a unified model that explains how formal valid deductive argumentation relates to argument schemes in general and to analogical argument schemes in particular. The model suggests “scheme-specific-validity” i.e. that there are contrasting species of validity for each type of argument scheme that derive from one generic conception of validity.

  20. Moon and Mars Analog Mission Activities for Mauna Kea 2012 (United States)

    Graham, Lee D.; Morris, Richard V.; Graff, Trevor G.; Yingst, R. Aileen; tenKate, I. L.; Glavin, Daniel P.; Hedlund, Magnus; Malespin, Charles A.; Mumm, Erik


    Rover-based 2012 Moon and Mars Analog Mission Activities (MMAMA) scientific investigations were recently completed at Mauna Kea, Hawaii. Scientific investigations, scientific input, and science operations constraints were tested in the context of an existing project and protocols for the field activities designed to help NASA achieve the Vision for Space Exploration. Initial science operations were planned based on a model similar to the operations control of the Mars Exploration Rovers (MER). However, evolution of the operations process occurred as the analog mission progressed. We report here on the preliminary sensor data results, an applicable methodology for developing an optimum science input based on productive engineering and science trades discussions and the science operations approach for an investigation into the valley on the upper slopes of Mauna Kea identified as "Apollo Valley".

  1. Theoretical ingredients of a Casimir analog computer. (United States)

    Rodriguez, Alejandro W; McCauley, Alexander P; Joannopoulos, John D; Johnson, Steven G


    We derive a correspondence between the contour integration of the Casimir stress tensor in the complex-frequency plane and the electromagnetic response of a physical dissipative medium in a finite real-frequency bandwidth. The consequences of this correspondence are at least threefold: First, the correspondence makes it easier to understand Casimir systems from the perspective of conventional classical electromagnetism, based on real-frequency responses, in contrast to the standard imaginary-frequency point of view based on Wick rotations. Second, it forms the starting point of finite-difference time-domain numerical techniques for calculation of Casimir forces in arbitrary geometries. Finally, this correspondence is also key to a technique for computing quantum Casimir forces at micrometer scales using antenna measurements at tabletop (e.g., centimeter) scales, forming a type of analog computer for the Casimir force. Superficially, relationships between the Casimir force and the classical electromagnetic Green's function are well known, so one might expect that any experimental measurement of the Green's function would suffice to calculate the Casimir force. However, we show that the standard forms of this relationship lead to infeasible experiments involving infinite bandwidth or exponentially growing fields, and a fundamentally different formulation is therefore required.

  2. [Petrological Analysis of Astrophysical Dust Analog Evolution (United States)

    Rietmeijer, Frans J. M.


    This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

  3. The Analog (Computer) As a Physiology Adjunct. (United States)

    Stewart, Peter A.


    Defines and discusses the analog computer and its use in a physiology laboratory. Includes two examples: (1) The Respiratory Control Function and (2) CO-Two Control in the Respiratory System. Presents diagrams and mathematical models. (MA)

  4. An Electrical Analog Computer for Poets (United States)

    Bruels, Mark C.


    Nonphysics majors are presented with a direct current experiment beyond Ohms law and series and parallel laws. This involves construction of an analog computer from common rheostats and student-assembled voltmeters. (Author/TS)

  5. Selective termination, fetal reduction and analogical reasoning. (United States)

    Pennings, G


    Analogical reasoning is a basic method in bioethics. Its main purpose is to transfer the rule from an existing or known situation to a new and problematic situation. This commentary applies the lifeboat analogy to the context of selective termination and fetal reduction. It turns out that the analogy is only partially helpful as the main principle in the case of selective termination is the procreative beneficence principle. However, the wide person-affecting form of this principle doubly justifies selective termination: i.e. one prevents the harm caused by the birth of an affected child and one increases the life chances of the remaining fetuses. I conclude, however, that all analogies are basically flawed since they assume that fetuses as such have interests. I argue that fetuses only have interests to the extent that they are potential future persons. Copyright © 2013 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  6. Optical analog-to-digital converter (United States)

    Vawter, G Allen [Corrales, NM; Raring, James [Goleta, CA; Skogen, Erik J [Albuquerque, NM


    An optical analog-to-digital converter (ADC) is disclosed which converts an input optical analog signal to an output optical digital signal at a sampling rate defined by a sampling optical signal. Each bit of the digital representation is separately determined using an optical waveguide interferometer and an optical thresholding element. The interferometer uses the optical analog signal and the sampling optical signal to generate a sinusoidally-varying output signal using cross-phase-modulation (XPM) or a photocurrent generated from the optical analog signal. The sinusoidally-varying output signal is then digitized by the thresholding element, which includes a saturable absorber or at least one semiconductor optical amplifier, to form the optical digital signal which can be output either in parallel or serially.

  7. Low Power Analog Design in Scaled Technologies

    CERN Document Server

    Baschirotto, A; Cocciolo, G; D’Amico, S; De Matteis, M; Delizia, P


    In this paper an overview on the main issues in analog IC design in scaled CMOS technology is presented. Decreasing the length of MOS channel and the gate oxide has led to undoubted advantages in terms of chip area, speed and power consumption (mainly exploited in the digital parts). Besides, some drawbacks are introduced in term of power leakage and reliability. Moreover, the scaled technology lower supply voltage requirement has led analog designers to find new circuital solution to guarantee the required performance.

  8. Analog modelling of obduction processes (United States)

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


    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

  9. Working memory predicts children's analogical reasoning. (United States)

    Simms, Nina K; Frausel, Rebecca R; Richland, Lindsey E


    Analogical reasoning is the cognitive skill of drawing relationships between representations, often between prior knowledge and new representations, that allows for bootstrapping cognitive and language development. Analogical reasoning proficiency develops substantially during childhood, although the mechanisms underlying this development have been debated, with developing cognitive resources as one proposed mechanism. We explored the role of executive function (EF) in supporting children's analogical reasoning development, with the goal of determining whether predicted aspects of EF were related to analogical development at the level of individual differences. We assessed 5- to 11-year-old children's working memory, inhibitory control, and cognitive flexibility using measures from the National Institutes of Health Toolbox Cognition battery. Individual differences in children's working memory best predicted performance on an analogical mapping task, even when controlling for age, suggesting a fundamental interrelationship between analogical reasoning and working memory development. These findings underscore the need to consider cognitive capacities in comprehensive theories of children's reasoning development. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Children's analogical reasoning about natural phenomena. (United States)

    Pauen, S; Wilkening, F


    This report investigates children's analogical reasoning in a physics task, using an analogy generated by the children rather than by the experimenter. A total of 127 elementary school children took part in three related studies. Children learned to predict the behavior of a balance scale. Later, they were asked to solve a force interaction problem. Two versions of the balance scale training were devised: version A suggested an incorrect solution to the target problem (negative analogy), and version B suggested a correct solution to the target problem (positive analogy). In Study 1, 9- to 10-year-olds showed spontaneous transfer in both training conditions. In Study 2, 7-year-olds did not show any transfer in the positive analogy condition. Study 3 revealed that the lack of transfer in younger children was not due to a failure either to notice the analogy or to perform the mapping. Instead, 7-year-olds transferred only selected aspects of the correct solution. Copyright 1997 Academic Press.

  11. Students' Pre- and Post-Teaching Analogical Reasoning When They Draw their Analogies (United States)

    Braga Mozzer, Nilmara; Justi, Rosária


    Analogies are parts of human thought. From them, we can acquire new knowledge or change that which already exists in our cognitive structure. In this sense, understanding the analogical reasoning process becomes an essential condition to understand how we learn. Despite the importance of such an understanding, there is no general agreement in cognitive science literature about this issue. In this study, we investigated students' analogical reasoning as a creative process where an environment was set up to foster the students' generating and explaining their own analogies. Data were gathered from pre- and post-teaching interviews, in which the 13-14-year-old students were asked to make comparisons that could explain how atoms are bound. Such data supported the discussion about how students reasoned analogically. Our results made it evident that the task aims and the students' salient knowledge exerted a great influence on the drawing of analogies.

  12. Analogical reasoning and the nature of context: a research note. (United States)

    Richardson, K; Webster, D S


    Recent theorising about children's reasoning has tended to move towards a 'contextualist' view of cognition and away from the idea of an overall, context-free, mechanism, varying in efficiency, which is the presupposition underlying traditional standardised reasoning tests. An earlier study suggesting improved reasoning performance among children on socio-cognitively meaningful versions of Raven's Matrices tended to support this shift. The main purpose of the study reported here was to observe whether a similar improvement would be found with contextually-based analogical reasoning problems as well. Ten analogy items from a standardised test were administered to 11-year-olds together with 10 structurally-equivalent knowledge-based items. The results reflected improved performance on the latter, overall, and additional analyses led to further suggestions about the nature of the 'contextual advantage' and the origins of item difficulty.

  13. Cisplatin Analogs Confer Protection against Cyanide Poisoning. (United States)

    Nath, Anjali K; Shi, Xu; Harrison, Devin L; Morningstar, Jordan E; Mahon, Sari; Chan, Adriano; Sips, Patrick; Lee, Jangwoen; MacRae, Calum A; Boss, Gerry R; Brenner, Matthew; Gerszten, Robert E; Peterson, Randall T


    Cisplatin holds an illustrious position in the history of chemistry most notably for its role in the virtual cure of testicular cancer. Here we describe a role for this small molecule in cyanide detoxification in vivo. Cyanide kills organisms as diverse as insects, fish, and humans within seconds to hours. Current antidotes exhibit limited efficacy and are not amenable to mass distribution requiring the development of new classes of antidotes. The binding affinity of the cyanide anion for the positively charged metal platinum is known to create an extremely stable complex in vitro. We therefore screened a panel of diverse cisplatin analogs and identified compounds that conferred protection from cyanide poisoning in zebrafish, mice, and rabbits. Cumulatively, this discovery pipeline begins to establish the characteristics of platinum ligands that influence their solubility, toxicity, and efficacy, and provides proof of concept that platinum-based complexes are effective antidotes for cyanide poisoning. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Optical domain analog to digital conversion methods and apparatus (United States)

    Vawter, Gregory A


    Methods and apparatus for optical analog to digital conversion are disclosed. An optical signal is converted by mapping the optical analog signal onto a wavelength modulated optical beam, passing the mapped beam through interferometers to generate analog bit representation signals, and converting the analog bit representation signals into an optical digital signal. A photodiode receives an optical analog signal, a wavelength modulated laser coupled to the photodiode maps the optical analog signal to a wavelength modulated optical beam, interferometers produce an analog bit representation signal from the mapped wavelength modulated optical beam, and sample and threshold circuits corresponding to the interferometers produce a digital bit signal from the analog bit representation signal.

  15. Connecting long distance: semantic distance in analogical reasoning modulates frontopolar cortex activity. (United States)

    Green, Adam E; Kraemer, David J M; Fugelsang, Jonathan A; Gray, Jeremy R; Dunbar, Kevin N


    Solving problems often requires seeing new connections between concepts or events that seemed unrelated at first. Innovative solutions of this kind depend on analogical reasoning, a relational reasoning process that involves mapping similarities between concepts. Brain-based evidence has implicated the frontal pole of the brain as important for analogical mapping. Separately, cognitive research has identified semantic distance as a key characteristic of the kind of analogical mapping that can support innovation (i.e., identifying similarities across greater semantic distance reveals connections that support more innovative solutions and models). However, the neural substrates of semantically distant analogical mapping are not well understood. Here, we used functional magnetic resonance imaging (fMRI) to measure brain activity during an analogical reasoning task, in which we parametrically varied the semantic distance between the items in the analogies. Semantic distance was derived quantitatively from latent semantic analysis. Across 23 participants, activity in an a priori region of interest (ROI) in left frontopolar cortex covaried parametrically with increasing semantic distance, even after removing effects of task difficulty. This ROI was centered on a functional peak that we previously associated with analogical mapping. To our knowledge, these data represent a first empirical characterization of how the brain mediates semantically distant analogical mapping.

  16. The role of natural analogs in the repository licensing process

    International Nuclear Information System (INIS)

    Murphy, W.M.


    The concept of a permanent geologic repository for high-level nuclear waste (NLW) is implicitly based on analogy to natural systems that have been stable for millions or billions of years. The time of radioactive and chemical toxicity of HLW exceeds the duration of human civilization, and it is impossible to demonstrate the accuracy of predictions of the behavior of engineered or social systems over such long periods

  17. The wave buoy analogy - estimating high-frequency wave excitations

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam


    The paper deals with the wave buoy analogy where a ship is considered as a wave buoy, so that measured ship responses are used as a basis to estimate wave spectra and associated sea state parameters. The study presented follows up on a previous paper, Nielsen [Nielsen UD. Response-based estimation...... be estimated reasonably well, even considering high-frequency wave components of a wind sea wave spectrum....

  18. What role for the anterior cingulate in analogical reasoning? (United States)

    O'Boyle, Michael W


    Abstract While prefrontal and frontal cortex of the brain are well documented to mediate many executive functions, including creativity, flexibility, and adaptability, the anterior cingulate cortex (ACC) is known to be involved in error detection and conflict resolution, and is crucial to reward-based learning. A case is made for the notion that any neural model of analogical reasoning must incorporate the critical (and specialized) contributions of the ACC.

  19. The restructuring of analogical reasoning in planetary science (United States)

    Soare, Richard J.

    Despite its ubiquity in planetary science, analogue-based reasoning largely has geomorphology and posit rules of use that facilitate the evaluation of Q y, I present four hypotheses concerning aeolian, fluvial and periglacial processes on Mars. Each of these hypotheses is evaluated in terms of the analogical rules presented. The fourth hypothesis is original to this thesis and suggests that a periglacial landscape comprising pingos and small-scale polygonal ground exists in an impact crater located in northwest Utopia Planitia.

  20. Mathematical analogies in physics. Thin-layer wave theory


    José M. Carcione; Vivian Grünhut; Ana Osella


    Field theory applies to elastodynamics, electromagnetism, quantum mechanics, gravitation and other similar fields of physics, where the basic equations describing the phenomenon are based on constitutive relations and balance equations. For instance, in elastodynamics, these are the stress-strain relations and the equations of momentum conservation (Euler-Newton law). In these cases, the same mathematical theory can be used, by establishing appropriate mathematical equivalences (or analogies)...

  1. A 13-Bits wilkinson analog-digital converter for NIM acquisition system

    International Nuclear Information System (INIS)

    Acosta Toledo, R.; Osorio Deliz, J.; Arista Romeu, E.; Fernandez, J.


    A new 13-bits Wilkinson analog-digital converter is described. The aim of this work is to describe the circuits of sample and hold, memory condensator loading and releasing PROM based control memory logic, zero level detection and correction. The converter is designed for the digital measurement of the peak amplitudes of pulses with statistical or periodical time distribution. The analog-digital converter may be used in spectrometric systems, multi-channel analysers or any similar PC based system

  2. Codebook Design and Hybrid Digital/Analog Coding for Parallel Rayleigh Fading Channels


    Shi, Shuying; Larsson, Erik G.; Skoglund, Mikael


    Low-delay source-channel transmission over parallel fading channels is studied. In this scenario separate sourceand channel coding is highly suboptimal. A scheme based on hybrid digital/analog joint source-channel coding istherefore proposed, employing scalar quantization and polynomial-based analog bandwidth expansion. Simulationsdemonstrate substantial performance gains. Funding agencies|European Community|248993|EL-LIIT||Knut and Alice Wallenberg Foundation||

  3. Anti-Plasmodium activity of ceramide analogs

    Directory of Open Access Journals (Sweden)

    Gatt Shimon


    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


    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. Riboswitch-based sensor in low optical background (United States)

    Harbaugh, Svetlana V.; Davidson, Molly E.; Chushak, Yaroslav G.; Kelley-Loughnane, Nancy; Stone, Morley O.


    Riboswitches are a type of natural genetic control element that use untranslated sequence in the RNA to recognize and bind to small molecules that regulate expression of that gene. Creation of synthetic riboswitches to novel ligands depends on the ability to screen for analyte binding sensitivity and specificity. In our work, we have coupled a synthetic riboswitch to an optical reporter assay based on fluorescence resonance energy transfer (FRET) between two genetically-coded fluorescent proteins. Specifically, a theophylline-sensitive riboswitch was placed upstream of the Tobacco Etch Virus (TEV) protease coding sequence, and a FRET-based construct, BFP-eGFP or eGFP-REACh, was linked by a peptide encoding the recognition sequence for TEV protease. Cells expressing the riboswitch showed a marked optical difference in fluorescence emission in the presence of theophylline. However, the BFP-eGFP FRET pair posses significant optical background that reduces the sensitivity of a FRET-based assay. To improve the optical assay, we designed a nonfluorescent yellow fluorescent protein (YFP) mutant called REACh (for Resonance Energy-Accepting Chromoprotein) as the FRET acceptor for eGFP. The advantage of using an eGFP-REACh pair is the elimination of acceptor fluorescence which leads to an improved detection of FRET via better signal-to-noise ratio. The EGFP-REACh fusion protein was constructed with the TEV protease cleavage site; thus upon TEV translation, cleavage occurs diminishing REACh quenching and increasing eGFP emission resulting in a 4.5-fold improvement in assay sensitivity.

  6. Neurotoxic Alkaloids: Saxitoxin and Its Analogs

    Directory of Open Access Journals (Sweden)

    Troco K. Mihali


    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.

  7. NaturAnalogs for the Unsaturated Zone

    Energy Technology Data Exchange (ETDEWEB)

    A. Simmons; A. Unger; M. Murrell


    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.

  8. Foucault's pendulum, a classical analog for the electron spin state (United States)

    Linck, Rebecca A.

    Spin has long been regarded as a fundamentally quantum phenomena that is incapable of being described classically. To bridge the gap and show that aspects of spin's quantum nature can be described classically, this work uses a classical Lagrangian based on the coupled oscillations of Foucault's pendulum as an analog for the electron spin state in an external magnetic field. With this analog it is possible to demonstrate that Foucault's pendulum not only serves as a basis for explaining geometric phase, but is also a basis for reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured electron spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon.

  9. Analog parallel processor hardware for high speed pattern recognition (United States)

    Daud, T.; Tawel, R.; Langenbacher, H.; Eberhardt, S. P.; Thakoor, A. P.


    A VLSI-based analog processor for fully parallel, associative, high-speed pattern matching is reported. The processor consists of two main components: an analog memory matrix for storage of a library of patterns, and a winner-take-all (WTA) circuit for selection of the stored pattern that best matches an input pattern. An inner product is generated between the input vector and each of the stored memories. The resulting values are applied to a WTA network for determination of the closest match. Patterns with up to 22 percent overlap are successfully classified with a WTA settling time of less than 10 microsec. Applications such as star pattern recognition and mineral classification with bounded overlap patterns have been successfully demonstrated. This architecture has a potential for an overall pattern matching speed in excess of 10 exp 9 bits per second for a large memory.

  10. Relational integration, inhibition, and analogical reasoning in older adults. (United States)

    Viskontas, Indre V; Morrison, Robert G; Holyoak, Keith J; Hummel, John E; Knowlton, Barbara J


    The difficulty of reasoning tasks depends on their relational complexity, which increases with the number of relations that must be considered simultaneously to make an inference, and on the number of irrelevant items that must be inhibited. The authors examined the ability of younger and older adults to integrate multiple relations and inhibit irrelevant stimuli. Young adults performed well at all but the highest level of relational complexity, whereas older adults performed poorly even at a medium level of relational complexity, especially when irrelevant information was presented. Simulations based on a neurocomputational model of analogical reasoning, Learning and Inference with Schemas and Analogies (LISA), suggest that the observed decline in reasoning performance may be explained by a decline in attention and inhibitory functions in older adults. copyright (c) 2004 APA, all rights reserved.

  11. Generalized analog thresholding for spike acquisition at ultralow sampling rates. (United States)

    He, Bryan D; Wein, Alex; Varshney, Lav R; Kusuma, Julius; Richardson, Andrew G; Srinivasan, Lakshminarayan


    Efficient spike acquisition techniques are needed to bridge the divide from creating large multielectrode arrays (MEA) to achieving whole-cortex electrophysiology. In this paper, we introduce generalized analog thresholding (gAT), which achieves millisecond temporal resolution with sampling rates as low as 10 Hz. Consider the torrent of data from a single 1,000-channel MEA, which would generate more than 3 GB/min using standard 30-kHz Nyquist sampling. Recent neural signal processing methods based on compressive sensing still require Nyquist sampling as a first step and use iterative methods to reconstruct spikes. Analog thresholding (AT) remains the best existing alternative, where spike waveforms are passed through an analog comparator and sampled at 1 kHz, with instant spike reconstruction. By generalizing AT, the new method reduces sampling rates another order of magnitude, detects more than one spike per interval, and reconstructs spike width. Unlike compressive sensing, the new method reveals a simple closed-form solution to achieve instant (noniterative) spike reconstruction. The base method is already robust to hardware nonidealities, including realistic quantization error and integration noise. Because it achieves these considerable specifications using hardware-friendly components like integrators and comparators, generalized AT could translate large-scale MEAs into implantable devices for scientific investigation and medical technology. Copyright © 2015 the American Physiological Society.

  12. Not All Analogies Are Created Equal: Associative and Categorical Analogy Processing following Brain Damage (United States)

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


    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…

  13. Students' Pre- and Post-Teaching Analogical Reasoning when They Draw Their Analogies (United States)

    Mozzer, Nilmara Braga; Justi, Rosaria


    Analogies are parts of human thought. From them, we can acquire new knowledge or change that which already exists in our cognitive structure. In this sense, understanding the analogical reasoning process becomes an essential condition to understand how we learn. Despite the importance of such an understanding, there is no general agreement in…

  14. Formal analogies in physics teacher education

    DEFF Research Database (Denmark)

    Avelar Sotomaior Karam, Ricardo; Ricardo, Elio


    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...

  15. Electronic devices for analog signal processing

    CERN Document Server

    Rybin, Yu K


    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...

  16. Changes in analogical reasoning in adulthood. (United States)

    Clark, E; Gardner, M K; Brown, G; Howell, R J


    This study sought to investigate adult intellectual development through an analysis of a particular type of cognitive ability, verbal analogical reasoning. The performance of 60 individuals between the ages of 20 and 79 was compared on 100 verbal analogies. The subjects consisted of six groups of ten individuals each (five males and five females), matched as a group for education and gender. Solution times and error rates served as the dependent measures. Results showed that there was a significant trend for the older subjects (60- and 70-year-olds) to be slower than the young subjects (20-, 30-, 40-, and 50-year-olds), but not necessarily more error prone. These data suggest that verbal analogical reasoning changes with age. Supplemental data demonstrated a change in other abilities as well (i.e., decline in perceptual-motor speed and spatial skill).

  17. Novel Gemini vitamin D3 analogs

    DEFF Research Database (Denmark)

    Okamoto, Ryoko; Gery, Sigal; Kuwayama, Yoshio


    We have synthesized 39 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] analogs having two side chains attached to carbon-20 (Gemini) with various modifications and compared their anticancer activities. Five structure-function rules emerged to identify analogs with enhanced anticancer activity. One...... of these active analogs, BXL-01-0126, was more potent than 1,25(OH)2D3 in mediating 50% clonal inhibition of cancer cell growth. Murine studies found that BXL-01-0126 and 1,25(OH)2D3 had nearly the same potency to raise serum calcium levels. Taken together, BXL-01-0126 when compared to 1,25(OH)2D3 has greater...

  18. 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)


    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.)

  19. Sleep promotes analogical transfer in problem solving. (United States)

    Monaghan, Padraic; Sio, Ut Na; Lau, Sum Wai; Woo, Hoi Kei; Linkenauger, Sally A; Ormerod, Thomas C


    Analogical problem solving requires using a known solution from one problem to apply to a related problem. Sleep is known to have profound effects on memory and information restructuring, and so we tested whether sleep promoted such analogical transfer, determining whether improvement was due to subjective memory for problems, subjective recognition of similarity across related problems, or by abstract generalisation of structure. In Experiment 1, participants were exposed to a set of source problems. Then, after a 12-h period involving sleep or wake, they attempted target problems structurally related to the source problems but with different surface features. Experiment 2 controlled for time of day effects by testing participants either in the morning or the evening. Sleep improved analogical transfer, but effects were not due to improvements in subjective memory or similarity recognition, but rather effects of structural generalisation across problems. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Capsule storage and density-analog techniques

    International Nuclear Information System (INIS)

    Paxton, H.C.


    Density-analog schemes for describing critical arrays of fissile units have a long history. They originated as methods for generalizing results of subcritical measurements on weapon capsules. Such measurements were needed to establish reasonably efficient rules for capsule storage. Although specific density-analog models have been improved throughout the years, they are now largely replaced by comprehensive tabulations of critical-lattice parameters. Certain simplified forms are still useful as convenient formulas for extrapolation or for gross sorting of safety features. (U.S.)

  1. HAPS, a Handy Analog Programming System

    DEFF Research Database (Denmark)

    Højberg, Kristian Søe


    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......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...

  2. Analogical reasoning abilities of recovering alcoholics. (United States)

    Gardner, M K; Clark, E; Bowman, M A; Miller, P J


    This study investigated analogical reasoning abilities of alcoholics who had been abstinent from alcohol for at least 1 year. Their performance was compared to that of nonalcoholic controls matched as a group for education, age, and gender. Solution times and error rates were modeled using a regression model. Results showed a nonsignificant trend for alcoholics to be faster, but more error prone, than controls. The same componential model applied to both groups, and fit them equally well. Although differences have been found in analogical reasoning ability between controls and alcoholics immediately following detoxification, we find no evidence of differences after extended periods of sobriety.

  3. Analogy in systems management: a theoretical inquiry

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, B.G.


    This theoretical analysis of the intuitive and diffuse characteristics of analogical reasoning processes is the first step in a research effort intended to lead to: understanding of common (and possibly costly) errors, pitfalls, travails, and problem-solving impediments; possible recommendations for improvements to organizational structures, control and coordination processes, and management information flows, and guidelines for a generalized analogical reasoning support framework (e.g., a handbook, a knowledge bank design, and/or even a software package/artificial intelligence program). 233 references.

  4. Design of analog integrated circuits and systems

    CERN Document Server

    Laker, Kenneth R


    This text is designed for senior or graduate level courses in analog integrated circuits or design of analog integrated circuits. This book combines consideration of CMOS and bipolar circuits into a unified treatment. Also included are CMOS-bipolar circuits made possible by BiCMOS technology. The text progresses from MOS and bipolar device modelling to simple one and two transistor building block circuits. The final two chapters present a unified coverage of sample-data and continuous-time signal processing systems.

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

    NARCIS (Netherlands)

    van de Plassche, R.J.


    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

  6. Mechatronics by Analogy and Application to Legged Locomotion (United States)

    Ragusila, Victor

    A new design methodology for mechatronic systems, dubbed as Mechatronics by Analogy (MbA), is introduced and applied to designing a leg mechanism. The new methodology argues that by establishing a similarity relation between a complex system and a number of simpler models it is possible to design the former using the analysis and synthesis means developed for the latter. The methodology provides a framework for concurrent engineering of complex systems while maintaining the transparency of the system behaviour through making formal analogies between the system and those with more tractable dynamics. The application of the MbA methodology to the design of a monopod robot leg, called the Linkage Leg, is also studied. A series of simulations show that the dynamic behaviour of the Linkage Leg is similar to that of a combination of a double pendulum and a spring-loaded inverted pendulum, based on which the system kinematic, dynamic, and control parameters can be designed concurrently. The first stage of Mechatronics by Analogy is a method of extracting significant features of system dynamics through simpler models. The goal is to determine a set of simpler mechanisms with similar dynamic behaviour to that of the original system in various phases of its motion. A modular bond-graph representation of the system is determined, and subsequently simplified using two simplification algorithms. The first algorithm determines the relevant dynamic elements of the system for each phase of motion, and the second algorithm finds the simple mechanism described by the remaining dynamic elements. In addition to greatly simplifying the controller for the system, using simpler mechanisms with similar behaviour provides a greater insight into the dynamics of the system. This is seen in the second stage of the new methodology, which concurrently optimizes the simpler mechanisms together with a control system based on their dynamics. Once the optimal configuration of the simpler system is

  7. The baby and the bath water: improving metaphors and analogies in high school biology texts (United States)

    Shors, Luke

    This dissertation is concerned with understanding how metaphors and analogies function in biology education and whether some of the philosophical critiques of the language used in the field of biology -- and in particular its accompanying metaphors and analogies, have a basis in the educational materials used to teach the subject. This inquiry was carried out through examining the pedagogical features and content of metaphors and analogies from three high school biology textbooks. After identifying over two hundred and twenty-five verbal and pictorial metaphors and analogies, these figures of speech were coded based on prior research that establishes effective characteristics for their use. In tandem with this quantitative analysis, a philosophical analysis considers how well the content of these metaphors and analogies aligns with current scientific understanding and what misunderstandings may be engendered through the use of these metaphors and analogies. The major findings of the analysis include: 1) Textbook authors are much more likely to utilize metaphors and analogies as well as signal their presence to students compared with past analyses; 2) A number of metaphors and analogies either contain errors in analogical mapping or use source analogues that are too antiquated to support today's students; 3) The content of many metaphors and analogies is frequently outdated in reference to current scientific understanding; and 4) Many metaphors and analogies tend to reinforce tacit elements of past scientific paradigms - these are termed 'reinforcing metaphors' in the dissertation and include nature as machine, nature as blueprint or information, nature as business and nature as war. The present work submits several implications for students learning biology as well as the manner in which students come to understand the natural world. The work suggests ways to reduce ineffective metaphors and analogies as well as reliance on reinforcing metaphors. It offers new

  8. Resveratrol analogs: promising chemopreventive agents. (United States)

    Ogas, Talysa; Kondratyuk, Tamara P; Pezzuto, John M


    Although resveratrol can modulate multiple stages of carcinogenesis, by most common standards it is not a good drug candidate. Resveratrol lacks potency, high efficacy, and target specificity; it is rapidly metabolized and serum concentrations are low. Using resveratrol as a scaffold, we produced over 100 derivatives, some of which have target specificity in the nanomolar range. Aromatase inhibition was enhanced over 6000-fold by using 1,3-thiazole as the central ring of resveratrol. Optimizing the substitution pattern of the two phenyl rings and the central heterocyclic linker led to selective QR1 induction with a CD value of 87 nM. Several derivatives have been selected for evaluation of synergistic effects. Preliminary results with pairs of compounds are promising and further experiments, in a constant multidrug manner, will allow us to create polygonograms for larger combinations of derivatives. The objective is to develop a highly efficacious cocktail of derivatives based on the structure of resveratrol. © 2013 New York Academy of Sciences.

  9. A novel natural analog in situ stabilization agent

    International Nuclear Information System (INIS)

    Shaw, P.


    This report summarizes the laboratory-scale test results on a synthetic analog of natural hematite cement for potential as an in situ treatment and stabilization agent for buried hazardous and radioactive waste. The concept is based on the principle that the ideal waste isolation materials are synthetic analogs of those natural encapsulating materials (cements), which are in equilibrium with the environment in which they occur. If equilibrium is achieved, then such materials will remain intact as long as the natural environment remains unchanged. The specific waste application is long-term stabilization of transuranic-contaminated waste pits and trenches at the Idaho National Engineering Laboratory (INEL). Six properties of the natural analog agent and resulting wasteforms are discussed to access the agent's effectiveness and implementability: hydraulic conductivity; compressive strength; mineralogy and microstructure; compatibility with possible waste materials, nitrates, machine cutting oil, and metallic iron; leachability of hazardous metals; and field application parameters. Data indicated that the iron waste encapsulation materials tested are appropriate choices for buried waste mixed with INEL soil. Iron oxide/gypsum INEL soil wasteforms have hydraulic conductivity values close to the regulatory limit. Wasteforms with soil and wastes have compressive strength greater than the regulatory minimum. Gypsum/iron oxide removes hazardous metals from solution by adsorption and would pass Toxicity Characteristic Leaching Procedure limits for most toxic metals. It appears to be chemically and physically inert with respect to the bulk of the waste materials likely to be found at INEL, and has properties conducive to jet grouting

  10. Structuring students’ analogical reasoning in solving algebra problem (United States)

    Lailiyah, S.; Nusantara, T.; Sa'dijah, C.; Irawan, E. B.; Kusaeri; Asyhar, A. H.


    The average achievement of Indonesian students’ mathematics skills according to Benchmark International Trends in Mathematics and Science Study (TIMSS) is ranked at the 38th out of 42 countries and according to the survey result in Program for International Student Assessment (PISA) is ranked at the 64th out of 65 countries. The low mathematics skill of Indonesian student has become an important reason to research more deeply about reasoning and algebra in mathematics. Analogical reasoning is a very important component in mathematics because it is the key to creativity and it can make the learning process in the classroom become effective. The major part of the analogical reasoning is about structuring including the processes of inferencing and decision-making happens. Those processes involve base domain and target domain. Methodologically, the subjects of this research were 42 students from class XII. The sources of data were derived from the results of thinks aloud, the transcribed interviews, and the videos taken while the subject working on the instruments and interviews. The collected data were analyzed using qualitative techniques. The result of this study described the structuring characteristics of students’ analogical reasoning in solving algebra problems from all the research subjects.

  11. Mathematical analogies in physics. Thin-layer wave theory

    Directory of Open Access Journals (Sweden)

    José M. Carcione


    Full Text Available Field theory applies to elastodynamics, electromagnetism, quantum mechanics, gravitation and other similar fields of physics, where the basic equations describing the phenomenon are based on constitutive relations and balance equations. For instance, in elastodynamics, these are the stress-strain relations and the equations of momentum conservation (Euler-Newton law. In these cases, the same mathematical theory can be used, by establishing appropriate mathematical equivalences (or analogies between material properties and field variables. For instance, the wave equation and the related mathematical developments can be used to describe anelastic and electromagnetic wave propagation, and are extensively used in quantum mechanics. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission problem of a thin layer embedded between dissimilar media, considering the presence of anisotropy and attenuation/viscosity in the viscoelastic case, conductivity in the electromagnetic case and a potential barrier in quantum physics (the tunnel effect. The analogy is mainly illustrated with geophysical examples of propagation of S (shear, P (compressional, TM (transverse-magnetic and TE (transverse-electric waves. The tunnel effect is obtained as a special case of viscoelastic waves at normal incidence.

  12. Biosignature Preservation and Detection in Mars Analog Environments. (United States)

    Hays, Lindsay E; Graham, Heather V; Des Marais, David J; Hausrath, Elisabeth M; Horgan, Briony; McCollom, Thomas M; Parenteau, M Niki; Potter-McIntyre, Sally L; Williams, Amy J; Lynch, Kennda L


    This review of material relevant to the Conference on Biosignature Preservation and Detection in Mars Analog Environments summarizes the meeting materials and discussions and is further expanded upon by detailed references to the published literature. From this diverse source material, there is a detailed discussion on the habitability and biosignature preservation potential of five primary analog environments: hydrothermal spring systems, subaqueous environments, subaerial environments, subsurface environments, and iron-rich systems. Within the context of exploring past habitable environments on Mars, challenges common to all of these key environments are laid out, followed by a focused discussion for each environment regarding challenges to orbital and ground-based observations and sample selection. This leads into a short section on how these challenges could influence our strategies and priorities for the astrobiological exploration of Mars. Finally, a listing of urgent needs and future research highlights key elements such as development of instrumentation as well as continued exploration into how Mars may have evolved differently from Earth and what that might mean for biosignature preservation and detection. Key Words: Biosignature preservation-Biosignature detection-Mars analog environments-Conference report-Astrobiological exploration. Astrobiology 17, 363-400.

  13. Analog optical computing by half-wavelength slabs (United States)

    Zangeneh-Nejad, Farzad; Khavasi, Amin; Rejaei, Behzad


    A new approach to perform analog optical differentiation is presented using half-wavelength slabs. First, a half-wavelength dielectric slab is used to design a first order differentiator. The latter works properly for both major polarizations, in contrast to our previously design based on Brewster effect (Youssefi et al., 2016). Inspired by the proposed dielectric differentiator, and by exploiting the unique features of graphene, we further design and demonstrate a reconfigurable and highly miniaturized differentiator using a half-wavelength plasmonic graphene film. To the best of our knowledge, our proposed graphene-based differentiator is even smaller than the most compact differentiator presented so far.

  14. Wafer-level chip-scale packaging analog and power semiconductor applications

    CERN Document Server

    Qu, Shichun


    This book presents a state-of-art and in-depth overview in analog and power WLCSP design, material characterization, reliability, and modeling. Recent advances in analog and power electronic WLCSP packaging are presented based on the development of analog technology and power device integration. The book covers in detail how advances in semiconductor content, analog and power advanced WLCSP design, assembly, materials, and reliability have co-enabled significant advances in fan-in and fan-out with redistributed layer (RDL) of analog and power device capability during recent years. Along with new analog and power WLCSP development, the role of modeling is a key to assure successful package design. An overview of the analog and power WLCSP modeling and typical thermal, electrical, and stress modeling methodologies is also provided. This book also: ·         Covers the development of wafer-level power discrete packaging with regular wafer-level design concepts and directly bumping technology ·    �...


    Directory of Open Access Journals (Sweden)

    Yunia Mardianis


    THE SYNTHESIS OF CURCUMINE ANALOGUE MONOCETONE FROM CINAMALDEHYDE AND ITS ACTIVITY TEST AS α-GLUCOCYDE ENZYME INHIBITOR The synthesis of curcumin analog monoketone as target compounds from cinnamaldehyde and inhibition assay against α-glucosidase enzyme had been performed. The stepwise of synthesis was performed by aldol condensation Claisen-Schmidt reaction and used ketone to give curcumin analog monoketone. The antidiabetic activity of curcumin analog was carried out by inhibition test against α-glucosidase enzyme isolated from rotten (Oryza sativa. The first step of synthesis (2E,5E-2,5-bis((E-3-phenylallylidene cyclopentanone was started by reacting cinnamaldehyde and cyclopentanone as monoketone in etanol as solvent. The synthesis was carried out in base condition (KOH by stirring at 52 °C for 50 minutes. The structures of product was identified by using FTIR, direct inlet-MS, 1H- and 13C-NMR. Futhermore, the activity of curcumin analog was tested against with α-glucosidase enzyme inhibition. The results show that the curcumin analog was yielded in 72.15% as yellow solid. The melting point of curcumin analog was at 196.20–200.10 °C. The inhibition against α-glucosidase enzyme indicated that the curcumin analog was potential to inhibit α-glucosidase enzyme with the highest activity by giving inhibtion percentage of about 70.71% at 2.5 mM.

  16. Electrostatic artificial eyelid actuator as an analog micromirror device (United States)

    Goodwin, Scott H.; Dausch, David E.; Solomon, Steven L.; Lamvik, Michael K.


    An electrostatic MEMS actuator is described for use as an analog micromirror device (AMD) for high performance, broadband, hardware-in-the-loop (HWIL) scene generation. Current state-of-the-art technology is based on resistively heated pixel arrays. As these arrays drive to the higher scene temperatures required by missile defense scenarios, the power required to drive the large format resistive arrays will ultimately become prohibitive. Existing digital micromirrors (DMD) are, in principle, capable of generating the required scene irradiances, but suffer from limited dynamic range, resolution and flicker effects. An AMD would be free of these limitations, and so represents a viable alternative for high performance UV/VIS/IR scene generation. An electrostatic flexible film actuator technology, developed for use as "artificial eyelid" shutters for focal plane sensors to protect against damaging radiation, is suitable as an AMD for analog control of projection irradiance. In shutter applications, the artificial eyelid actuator contained radius of curvature as low as 25um and operated at high voltage (>200V). Recent testing suggests that these devices are capable of analog operation as reflective microcantilever mirrors appropriate for scene projector systems. In this case, the device would possess larger radius and operate at lower voltages (20-50V). Additionally, frame rates have been measured at greater than 5kHz for continuous operation. The paper will describe the artificial eyelid technology, preliminary measurements of analog test pixels, and design aspects related to application for scene projection systems. We believe this technology will enable AMD projectors with at least 5122 spatial resolution, non-temporally-modulated output, and pixel response times of <1.25ms.

  17. Analog System of Detonations with Loss and Stability of the Analog System (United States)

    Sun, Yuanxiang; Wang, Cheng; Group of Computationa Fluid Dynamics Team


    Analog system of detonation is a simplified model of the Euler system. Analog system removes unnecessary details of the Euler system and reduces mathematical difficulty Analog system with losses and reaction mechanism that applicable for condensed-phase detonation is studied to examine whether the analog system in this paper is valid Details are as follows: 1. The relationship of detonation velocity vs. loss parameter is analytically solved, and a minimal state-dependence of the reaction rate n required for this relationship to exhibit a critical behavior (i.e., a turning point) is examined The results agree with the limits which derived from Euler system. 2. Normal-mode method is used to study the stability of the analog system. A radiation (closure) condition is derived and applied at the end of the reaction zone. An analysis is performed to investigate whether the ideal, steady-state detonation can keep stable to small perturbations 3. Because analog system with loss can be more unstable than the ideal one. An numerical simulation is used to examine the detonation stability near the loss limits. The results above show that the analog system is basically valid for condensed-phase detonation.

  18. A physical analogy to fuzzy clustering

    DEFF Research Database (Denmark)

    Jantzen, Jan


    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...

  19. LHRH analogs in treatment of breast cancer

    International Nuclear Information System (INIS)

    Rajec, J.; Dzurillova, L.


    Hormonal therapy is an important and effective part of treatment of the hormonal positive breast cancer. Drugs from the group of LHRH analogs cause reversible ovarian suppression in premenopausal women with breast cancer. The following article deals with actual possibilities of their usage in the adjuvant therapy as well as in the metastatic setting. (author)


    DEFF Research Database (Denmark)

    Gaunholt, Hans


    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...

  1. A high-speed analog neural processor

    NARCIS (Netherlands)

    Masa, P.; Masa, Peter; Hoen, Klaas; Hoen, Klaas; Wallinga, Hans


    Targeted at high-energy physics research applications, our special-purpose analog neural processor can classify up to 70 dimensional vectors within 50 nanoseconds. The decision-making process of the implemented feedforward neural network enables this type of computation to tolerate weight

  2. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper


    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...

  3. An iconic, analogical approach to grammaticalization

    NARCIS (Netherlands)

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


    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,

  4. Metaphor, Simile, Analogy and the Brain (United States)

    Riddell, Patricia


    Fox argues that the poetic function of language fulfils the human need to symbolise. Metaphor, simile and analogy provide examples of the ways in which symbolic language can be used creatively. The neural representations of these processes therefore provide a means to determine the neurological basis of creative language. Neuro-imaging has…

  5. The GMO-Nanotech (Dis)Analogy? (United States)

    Sandler, Ronald; Kay, W. D.


    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…

  6. Analog Experiment for rootless cone eruption (United States)

    Noguchi, R.; Hamada, A.; Suzuki, A.; Kurita, K.


    Rootless cone is a unique geomorphological landmark to specify igneous origin of investigated terrane, which is formed by magma-water interaction. To understand its formation mechanism we conducted analog experiment for heat-induced vesiculation by using hot syrup and sodium bicarbonate solution.

  7. A Mechanical Analogy for Ohm's Law. (United States)

    do Couto Tavares, Milton; And Others


    A mechanical analogy between the microscopic motion of a charged carrier in an ordinary resistor and the macroscopic motion of a ball falling along a slanted board covered with a lattice of nails is introduced. The Drude model is also introduced to include the case of inelastic collisions. Computer simulation of the motion is described. (KR)

  8. Analog circuit design designing waveform processing circuits

    CERN Document Server

    Feucht, Dennis


    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.

  9. The Structure of Analogical Models in Science. (United States)


    electric current. Finally, a familiar but useful example is the standard mathematical technique of analogizing from two- or three-dimensional spaces to n...loose collection of similar properties, events and relationships, such as "produced by striking water, etc./produced by striking gongs, violins , etc

  10. Refinement of Research Surveying in Software Methodologies by Analogy: finding your patch

    Directory of Open Access Journals (Sweden)

    Eugene Doroshenko


    Full Text Available To enhance research surveying in software methodologies, a model is introduced that can indicate field maturity based on vocabulary and relevant literature. This model is developed by drawing analogies with software methodologies. Two analogies are used: software models and software life cycles or processes. How this model can reduce research surveying problems for researchers is described using extracts from application results as examples. Although the model does support research surveying activities, it cannot choose the subject for the researcher.

  11. Analog-to-digital conversion using custom CMOS analog memory for the EOS time projection chamber

    International Nuclear Information System (INIS)

    Lee, K.L.; Arthur, A.A.; Jones, R.W.; Matis, H.S.; Nakamura, M.; Kleinfelder, S.A.; Ritter, H.G.; Wienman, H.H.


    This paper describes the multiplexing scheme of custom CMOS analog memory integrated circuits, 16 channels x 256 cells, into analog to digital converters (ADC's) to handle 15,360 signal channels of a time projection, chamber detector system. Primary requirements of this system are high density, low power and large dynamic range. The analog memory device multiplexing scheme was designed to digitize the information stored in the memory cells. The digitization time of the ADC's and the settling times for the memory unit were carefully interleaved to optimize the performance and timing during the multiplexing operation. This kept the total number of ADC's, a costly and power dissipative component, to an acceptable minimum

  12. Analogy, an Alternative Model.
 Critics to the standard model of analogical problems solving and proposals for an alternative one

    Directory of Open Access Journals (Sweden)

    Ricardo A. Minervino


    Full Text Available The authors made an extension of Hofstadter‘s criticisms against the standard approach in analogical thinking represented by the structure-mapping theory of Gentner and the multiconstraint theory of Holyoak and Thagard. Based on this extension, they proposed a non-serial model of analogical problem solving. Against the standard approach, the model postulates that: (a people detect and evaluate differences between mapped elements before the subprocess of inference generation and consider them in order to control it, and (b properties of an element that explain why the element could fill a certain role in the base problem resolution (PERs play a crucial role in these detection and evaluation operations, and also in post-inferences subprocesses. An experiment showed that: (a people detect and evaluate the relevance of differences between mapped elements before inference generation, (b that they inhibit the generation of literal inferences when they face relevant differences, and (c that they stop the subprocess when they recognize insuperable ones. The results also showed that base PERs are reactivated at different moments of analogical transfer. The data obtained are incompatible with the standard theories of analogical thinking, which treat inference generation as a syntactic mechanism and exclude contextual semantic analysis from the study of analogy

  13. De Analogía a Digitalia

    Directory of Open Access Journals (Sweden)

    Dr. Xaime Fandiño Alonso


    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

  14. Drug Development of the Antimalarial Agent Artemisinin: Total Synthesis, Analog Synthesis, and Structure-Activity Relationship Studies (United States)


    jHoluenesulfonyl hydrazide in tetrahydrofuran (THF), solvolysis of the ketal group and subsequent hydrazone formation was observed. Under base...ARTEMISININ: TOTAL SYNTHESIS , ANALOG SYNTHESIS , AND STRUCTURE-ACTIVITY RELATIONSHIP STUDIES mc Mitchell A. Avery, Ph.D. SRI International...Antimalarial Agent Artemisinin: Total Synthesis , Analog Synthesis and Structure-Activity Relationship Studies 12 PERSONAL AUTHOR(S) Mitchell A

  15. Use of the FAR Guide to Present a Pedagogical Analogical Model of Gel Electrophoresis in Year 10 Science (United States)

    Davis, James


    This paper is a qualitative, practice based study describing the use of the Focus-Action-Reflection (FAR) Guide (Harrison & Treagust, 2000) to address the shortcomings of a pedagogical analogical model in Year 10 Science. The aim of this paper is to present my experience of the FAR Guide in relation to an analogical model that gave rise to…

  16. Human Health Countermeasures - Partial-Gravity Analogs Workshop (United States)

    Barr, Yael; Clement, Gilles; Norsk, Peter


    The experimental conditions that were deemed the most interesting by the HHC Element lead scientists are those permitting studies of the long-term effects of exposure to (a) chronic rotation when supine or in head down tilt (ground-based); and (b) long-radius centrifugation (space based). It is interesting to note that chronic ground based slow rotation room studies have not been performed since the 1960's, when the USA and USSR were investigating the potential use of AG for long-duration space missions. On the other hand, the other partial gravity analogs, i.e., parabolic flight, HUT, suspension, and short-radius centrifugation, have been regularly used in the last three decades (see review in Clément et al. 2015). Based on the workshop evaluations and the scores by the HHC scientific disciplines indicated in tables 3 and 4, simulation of partial G between 0 and 1 should be prioritized as follows: Priority 1. Chronic space-based partial-G analogs: a. Chronic space-based long-radius centrifugation. The ideal scenario would be chronic long-radius centrifugation of cells, animals and humans in a translational research approach - ideally beyond low earth orbit under deep space environmental effects and at various rotations - to obtain different G-effects. In this scenario, all physiological systems could be evaluated and the relationship between physiological response and G level established. This would be the most integrative way of defining, for the first time ever, G-thresholds for each physiological system. b. Chronic space-based centrifugation of animals. Chronic centrifugation of rodents at various G levels in space would allow for determination of AG thresholds of protection for each physiological system. In this case, all physiological systems will be of interest. Intermittent centrifugation will be of secondary interest. c. Chronic space-based centrifugation of cell cultures (RWV). Bioreactor studies of cells and cell cultures of various tissues at various G

  17. Automatic analog IC sizing and optimization constrained with PVT corners and layout effects

    CERN Document Server

    Lourenço, Nuno; Horta, Nuno


    This book introduces readers to a variety of tools for automatic analog integrated circuit (IC) sizing and optimization. The authors provide a historical perspective on the early methods proposed to tackle automatic analog circuit sizing, with emphasis on the methodologies to size and optimize the circuit, and on the methodologies to estimate the circuit’s performance. The discussion also includes robust circuit design and optimization and the most recent advances in layout-aware analog sizing approaches. The authors describe a methodology for an automatic flow for analog IC design, including details of the inputs and interfaces, multi-objective optimization techniques, and the enhancements made in the base implementation by using machine leaning techniques. The Gradient model is discussed in detail, along with the methods to include layout effects in the circuit sizing. The concepts and algorithms of all the modules are thoroughly described, enabling readers to reproduce the methodologies, improve the qual...

  18. A fast and accurate method for the pharmacokinetic research of four coumarin analogs in Fructus cnidii using capillary electro-chromatography with a methacrylate ester-based monolithic column. (United States)

    Chen, Zhao; Xu, Aili; Bi, Xiaoli; Luo, Wenhui; Li, Ji; Fan, Guorong; Sun, Dongmei


    In the present study, a monolithic capillary column with higher permeability was developed for the in vivo discrimination of four coumarin analogs (bergapten, 2'-acetylangelicin, imperatorin, and osthole) that typically require long separation times in HPLC. Instead of conventional methacrylate ester monolith (containing 19.5% porogen) with insufficient permeability (K = 1.52 - 1.66 × 10 -14 M 2 ) for plasma sample, the proposed column (20.5% porogen) had better permeability (around 3.80 × 10 -14 M 2 ) while properties such as pore distribution, stability, and resolution changed slightly. As a result, due to the negatively charged electro-dynamic flow of the methacrylate ester groups in the monolith, the migration of targeted analytes was achieved within 6 min (compared with 30 min in HPLC) with acceptable resolution and improved sensitivity (0.005-0.02 μg/mL vs. 0.04 μg/mL). The proposed method was also applied to pharmacokinetic research: accelerated solvent extraction (ASE) was used to improve the extraction efficiency, which prepared extract much faster and more pure than conventional methods. As the pharmacokinetic parameters indicated, the monolithic capillary electro-chromatography method was efficient, sensitive, specific, and durable, guaranteeing its utility for the determination of multiple structure-related compounds in rat plasma. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. The Altiplano-Puna Plateau as an Analog for Mars (United States)

    de Silva, S. L.; Byrnes, J. M.; Crown, D. A.; Zimbelman, J. R.; Jimenez, N.; Bills, B. G.


    The Altiplano-Puna Plateau of the Central Andes of Bolivia has experienced a climatic and geologic evolution that has resulted in an enticing array of potential Martian analog geologic environments and features. Elevated ~3 ? 4km above the adjacent Atacama desert, the Altiplano-Puna is the highest plateau in the world associated with extensive volcanism; it is second only to Tibet in height and extent. The high elevation adds extreme cold, wind, and lower atmospheric pressure to a hyper-arid climate making this region a compelling analog environment for Mars. The plateau is dominated by the Altiplano basin, which developed as a major intermontane basin since at least 25Ma. This is flanked by major volcanic provinces to the east and south. To the south is the Altiplano-Puna Volcanic Complex (APVC) where regionally extensive ignimbrite sheets and associated eruptive centers are amongst the largest known volcanic features in the world. The region has proven to be an excellent natural laboratory for remote sensing and field-based studies of volcanism. The extreme cold, wind, and the wide diurnal temperature range, results in geomorphic expressions dominated by physical weathering and aeolian erosion. These factors make this region one of the premier analog environments for Martian features like Amazonis Planitia, and Hadriaca, Alba, and Tyrrhena paterae, as well as the enigmatic Medusa Fossae Formation (MFF) materials. Large ignimbrite shields, are prominent features of volcanic geology of the plateau and are the subject of an ongoing terrestrial analog study for the MFF. The Altiplano basin preserves a long Pleistocene lake history recorded in a well-preserved lake shore geomorphology consisting of both erosional and depositional features. These features are easily identified and studied in the field and on remotely sensed images and may lend valuable insight into the debate over putative paleoshorelines in the northern plains of Mars. Throughout the basin are several


    Directory of Open Access Journals (Sweden)

    Bayu Kanetro


    Full Text Available The aims of this research were to determine the best of local legume sprout as raw material of meat analog, based on its texture, sensory (preference properties, and the ratio of arginine/lysine, compared to meat analog from soybean. Meat analogs were made of protein of local legumes sprout, which were velvet beans, cowpeas, and winged beans that had been germinated for 48, 36 and 24 hr respectively. The protein of velvet beans, cowpeas, and winged beans sprout for meat analog production were extracted at pH 9 and precipitated at pH 4, 5, and 5 respectively. Hence their products were analyzed the texture, the sensory properties (the hedonic scales of color, texture, odor, taste, and overall, and the ratio of arginine/lysine. The characteristics of meat analog from the legumes sprout were compared to meat analog from soybean for determination of the best legume sprout as raw material of meat analog. The result of this research showed the properties of meat analog from winged bean and cowpeas sprouts were better than velvet beans sprout. The meat analog from soybean was still better than meat analog from the local legumes sprout, especially its texture. The arginine content, that was known as  hypocholesterolemic and hypoglycemic component,  of meat analog from cowpeas sprout was lower than meat analog from soybean, but its ratio of arginie/lysine was not signifi cantly different. While the ratio of arginine/lysine of meat analog from the other legumes sprout were lower than meat analog from soybean. Therefore the meat analog from cowpeas sprout was chosen as the best product and was potential as functional food especially for reducing blood cholesterol. Keywords: Meat analog, sprout, local legumes, arginine/lysine ratio   ABSTRAK Tujuan penelitian ini adalah untuk menentukan jenis kecambah kacang-kacangan lokal terbaik sebagai bahan baku kedelai berdasarkan tekstur, sifat sensoris, dan rasio arginin/lisin dibandingkan meat analog dari biji

  1. Analogical reasoning in children with specific language impairment: Evidence from a scene analogy task. (United States)

    Krzemien, Magali; Jemel, Boutheina; Maillart, Christelle


    Analogical reasoning is a human ability that maps systems of relations. It develops along with relational knowledge, working memory and executive functions such as inhibition. It also maintains a mutual influence on language development. Some authors have taken a greater interest in the analogical reasoning ability of children with language disorders, specifically those with specific language impairment (SLI). These children apparently have weaker analogical reasoning abilities than their aged-matched peers without language disorders. Following cognitive theories of language acquisition, this deficit could be one of the causes of language disorders in SLI, especially those concerning productivity. To confirm this deficit and its link to language disorders, we use a scene analogy task to evaluate the analogical performance of SLI children and compare them to controls of the same age and linguistic abilities. Results show that children with SLI perform worse than age-matched peers, but similar to language-matched peers. They are more influenced by increased task difficulty. The association between language disorders and analogical reasoning in SLI can be confirmed. The hypothesis of limited processing capacity in SLI is also being considered.

  2. General and specialized brain correlates for analogical reasoning: A meta-analysis of functional imaging studies. (United States)

    Hobeika, Lucie; Diard-Detoeuf, Capucine; Garcin, Béatrice; Levy, Richard; Volle, Emmanuelle


    Reasoning by analogy allows us to link distinct domains of knowledge and to transfer solutions from one domain to another. Analogical reasoning has been studied using various tasks that have generally required the consideration of the relationships between objects and their integration to infer an analogy schema. However, these tasks varied in terms of the level and the nature of the relationships to consider (e.g., semantic, visuospatial). The aim of this study was to identify the cerebral network involved in analogical reasoning and its specialization based on the domains of information and task specificity. We conducted a coordinate-based meta-analysis of 27 experiments that used analogical reasoning tasks. The left rostrolateral prefrontal cortex was one of the regions most consistently activated across the studies. A comparison between semantic and visuospatial analogy tasks showed both domain-oriented regions in the inferior and middle frontal gyri and a domain-general region, the left rostrolateral prefrontal cortex, which was specialized for analogy tasks. A comparison of visuospatial analogy to matrix problem tasks revealed that these two relational reasoning tasks engage, at least in part, distinct right and left cerebral networks, particularly separate areas within the left rostrolateral prefrontal cortex. These findings highlight several cognitive and cerebral differences between relational reasoning tasks that can allow us to make predictions about the respective roles of distinct brain regions or networks. These results also provide new, testable anatomical hypotheses about reasoning disorders that are induced by brain damage. Hum Brain Mapp 37:1953-1969, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  3. Drift chamber and pulse height readout systems using analog multiplexing

    International Nuclear Information System (INIS)

    Cisneros, E.L; Kang, H.K.; Hall, J.N.; Larsen, R.S.


    Drift chamber and pulse-height readout systems are being developed for use in a new large scale detector at the SPEAR colliding beam facility. The systems are based upon 32 channels of sample-and-hold together with an analog multiplexer in a single-width CAMAC module. The modules within each crate are scanned by an autonomous controller containing a single ADC and memory plus arithmetic capability for offset, gain and linearity corrections. The drift chamber module has a facility for extracting hit wire information for use in trigger decision circuitry

  4. Implementing size-optimal discrete neural networks require analog circuitry

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.


    This paper starts by overviewing results dealing with the approximation capabilities of neural networks, as well as bounds on the size of threshold gate circuits. Based on a constructive solution for Kolmogorov`s superpositions the authors show that implementing Boolean functions can be done using neurons having an identity transfer function. Because in this case the size of the network is minimized, it follows that size-optimal solutions for implementing Boolean functions can be obtained using analog circuitry. Conclusions and several comments on the required precision are ending the paper.

  5. Optimal neural computations require analog processors

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.


    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).

  6. Analog data transmission via fiber optics

    International Nuclear Information System (INIS)

    Cisneros, E.L.; Burgueno, G.F.


    In the SLAC Linear Collider Detector (SLD), as in most high-energy particle detectors, the electromagnetic noise environment is the limiting factor in electronic readout performance. Front-end electronics are particulary susceptible to electromagnetic interference (EMI), and great care has been taken to minimize its effects. The transfer of preprocessed analog signals from the detector environs, to the remote digital processing electronics, by conventional means (via metal conductors), may ultimately limit the performance of the system. Because it is highly impervious to EMI and ground loops, a fiber-optic medium has been chosen for the transmission of these signals. This paper describes several fiber-optic transmission schemes which satisfy the requirements of the SLD analog data transmission

  7. Performance of the Analog Moving Window Detector

    DEFF Research Database (Denmark)

    Hansen, V. Gregers


    A type of analog integrating moving window detector for use with a scanning pulse radar is examined. A performance analysis is carried out, which takes into account both the radiation pattern of the antenna and the dynamic character of the detection process due to the angular scanning of the ante......A type of analog integrating moving window detector for use with a scanning pulse radar is examined. A performance analysis is carried out, which takes into account both the radiation pattern of the antenna and the dynamic character of the detection process due to the angular scanning....... Finally the influence on detection performance of the width used for the moving window is investigated....

  8. The influence of analogical reasoning instruction on the pedagogical reasoning ability of preservice elementary teachers (United States)

    James, Mark Charles

    Novice teachers with little prior knowledge of science concepts often resort to teaching science as a litany of jargon and definitions. The primary objective of this study was to establish the efficacy of analogy-based pedagogy on influencing the teaching performance of preservice elementary teachers, a group that has been identified for their particular difficulties in teaching science content. While numerous studies have focused on the efficacy of analogy-based instruction on the conceptual knowledge of learners, this was the first study to focus on the influence of analogy-based pedagogy instruction on the teaching performance of novice teachers. The study utilized a treatment/contrast group design where treatment and contrast groups were obtained from intact sections of a university course on methods of teaching science for preservice elementary education students. Preservice teachers in the treatment group were provided instruction in pedagogy that guided them in the generation of analogies to aid in the explanation phase of their learning cycle lessons. The process of generating and evaluating analogies for use in teaching was instrumental in focusing the preservice teachers' lesson planning efforts on critical attributes in target concepts, and away from misplaced concentrations on jargon and definitions. Teaching performance was primarily analyzed using coded indicants of Shulman's (1986) six stages of pedagogical reasoning ability. The primary data source was preservice teachers' work submitted for a major course assignment where the preservice teachers interviewed an elementary school student to gauge prior knowledge of Newtonian force concepts. The culmination of the semester-long assignment was the design of an individualized lesson that was presented by the preservice teachers to individual elementary school students. The results of this study strongly suggest that instruction in methods to include analogy-based pedagogy within a learning cycle lesson

  9. DIY Hybrid Analog/Digital Modular Synthesis


    Surges, Greg


    This paper describes three hardware devices for integrating modular synthesizers with computers, each with a different approach to the relationship between hardware and software. The devices discussed are the USB-Octomod, an 8-channel OSC-compatible computer-controlled control-voltage generator, the tabulaRasa, a hardware table-lookup oscillator synthesis module with corresponding waveform design software, and the pucktronix.snake.corral, a dual 8x8 computer-controlled analog signal routing m...

  10. Pyrrolidine nucleotide analogs with a tunable conformation

    Czech Academy of Sciences Publication Activity Database

    Poštová Slavětínská, Lenka; Rejman, Dominik; Pohl, Radek


    Roč. 10, Aug 22 (2014), s. 1967-1980 ISSN 1860-5397 R&D Projects: GA ČR GA13-24880S Institutional support: RVO:61388963 Keywords : conformation * NMR * nucleic acids * nucleotide analog * phosphonic acid * pseudorotation * pyrrolidine Subject RIV: CC - Organic Chemistry Impact factor: 2.762, year: 2014

  11. How to use analogies for breakthrough innovations


    Schild, Katharina; Herstatt, Cornelius; Lüthje, Christian


    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...

  12. Performance of MSGC with analog pipeline readout

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, F. [Universidad de Santiago de Compostela (Spain); Adeva, B. [Universidad de Santiago de Compostela (Spain); Gracia, G. [Universidad de Santiago de Compostela (Spain); Lopez, M.A. [Universidad de Santiago de Compostela (Spain); Nunez, T. [Universidad de Santiago de Compostela (Spain); Pazos, A. [Universidad de Santiago de Compostela (Spain); Plo, M. [Universidad de Santiago de Compostela (Spain); Rodriguez, A. [Universidad de Santiago de Compostela (Spain); Santamarina, C. [Universidad de Santiago de Compostela (Spain); Vazquez, P. [Universidad de Santiago de Compostela (Spain)


    We analyse some of the performance characteristics of a chromium MSGC operated with Ar-DME 50%-50% in a test beam at CERN. Excellent signal-to-noise ratio and efficiency has been achieved with this gas mixture using cathode analog pipeline readout. We also determine optimal parameters for the sampling algorithm in order to work in a random trigger experiment (fixed target). (orig.).

  13. An introduction to analog and digital communications

    CERN Document Server

    Haykin, Simon


    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.

  14. The 2012 Moon and Mars Analog Mission (United States)

    Graham, Lee


    The 2012 Moon and Mars Analog Mission Activities (MMAMA) scientific investigations were completed on Mauna Kea volcano in Hawaii in July 2012. The investigations were conducted on the southeast flank of the Mauna Kea volcano at an elevation of approximately 11,500 ft. This area is known as "Apollo Valley" and is in an adjacent valley to the Very Large Baseline Array dish antenna.

  15. Performance of MSGC with analog pipeline readout

    International Nuclear Information System (INIS)

    Gomez, F.; Adeva, B.; Gracia, G.; Lopez, M.A.; Nunez, T.; Pazos, A.; Plo, M.; Rodriguez, A.; Santamarina, C.; Vazquez, P.


    We analyse some of the performance characteristics of a chromium MSGC operated with Ar-DME 50%-50% in a test beam at CERN. Excellent signal-to-noise ratio and efficiency has been achieved with this gas mixture using cathode analog pipeline readout. We also determine optimal parameters for the sampling algorithm in order to work in a random trigger experiment (fixed target). (orig.)

  16. Prostaglandin analogs in the treatment of glaucoma. (United States)

    Hejkal, T W; Camras, C B


    Prostaglandin (PG) analogs are some of the most recent additions to the list of ocular hypotensive medications. Two analogs of naturally occurring PGs are available commercially, isopropyl unoprostone (Rescula [Ciba Vision, Atlanta, GA]) and latanoprost (Xalatan [Pharmacia & Upjohn, Bridgewater, NJ]). Presently, latanoprost 0. 005% is the only PG analog commercially available in the United States. These agents have been shown to be the most effective topical medications for reducing intraocular pressure. They have a different mechanism of action than other ocular hypotensives, and act primarily by increasing uveoscleral outflow. Because of this, PGs have a substantial additive effect when used with agents that reduce aqueous production (eg, beta blockers or carbonic anhydrase inhibitors) or that increase trabecular outflow facility (eg, pilocarpine). Local side effects include mild conjunctival hyperemia and local irritation, darkening of iris color, increased growth of eyelashes, and a possible association with cystoid macular edema or iritis in some patients with other risk factors. No systemic side effects have been proven to be caused by latanoprost. Recommended dosing is once daily at bedtime.

  17. Clinical utility of insulin and insulin analogs (United States)

    Sanlioglu, Ahter D.; Altunbas, Hasan Ali; Balci, Mustafa Kemal; Griffith, Thomas S.; Sanlioglu, Salih


    Diabetes is a pandemic disease characterized by autoimmune, genetic and metabolic abnormalities. While insulin deficiency manifested as hyperglycemia is a common sequel of both Type-1 and Type-2 diabetes (T1DM and T2DM), it does not result from a single genetic defect—rather insulin deficiency results from the functional loss of pancreatic β cells due to multifactorial mechanisms. Since pancreatic β cells of patients with T1DM are destroyed by autoimmune reaction, these patients require daily insulin injections. Insulin resistance followed by β cell dysfunction and β cell loss is the characteristics of T2DM. Therefore, most patients with T2DM will require insulin treatment due to eventual loss of insulin secretion. Despite the evidence of early insulin treatment lowering macrovascular (coronary artery disease, peripheral arterial disease and stroke) and microvascular (diabetic nephropathy, neuropathy and retinopathy) complications of T2DM, controversy exists among physicians on how to initiate and intensify insulin therapy. The slow acting nature of regular human insulin makes its use ineffective in counteracting postprandial hyperglycemia. Instead, recombinant insulin analogs have been generated with a variable degree of specificity and action. Due to the metabolic variability among individuals, optimum blood glucose management is a formidable task to accomplish despite the presence of novel insulin analogs. In this article, we present a recent update on insulin analog structure and function with an overview of the evidence on the various insulin regimens clinically used to treat diabetes. PMID:23584214

  18. Individual differences in spontaneous analogical transfer. (United States)

    Kubricht, James R; Lu, Hongjing; Holyoak, Keith J


    Research on analogical problem solving has shown that people often fail to spontaneously notice the relevance of a semantically remote source analog when solving a target problem, although they are able to form mappings and derive inferences when given a hint to recall the source. Relatively little work has investigated possible individual differences that predict spontaneous transfer, or how such differences may interact with interventions that facilitate transfer. In this study, fluid intelligence was measured for participants in an analogical problem-solving task, using an abridged version of the Raven's Progressive Matrices (RPM) test. In two experiments, we systematically compared the effect of augmenting verbal descriptions of the source with animations or static diagrams. Solution rates to Duncker's radiation problem were measured across varying source presentation conditions, and participants' understanding of the relevant source material was assessed. The pattern of transfer was best fit by a moderated mediation model: the positive impact of fluid intelligence on spontaneous transfer was mediated by its influence on source comprehension; however, this path was in turn modulated by provision of a supplemental animation via its influence on comprehension of the source. Animated source depictions were most beneficial in facilitating spontaneous transfer for those participants with low scores on the fluid intelligence measure.

  19. Targeting thyroid diseases with TSH receptor analogs. (United States)

    Galofré, Juan C; Chacón, Ana M; Latif, Rauf


    The thyroid-stimulating hormone (TSH) receptor (TSHR) is a major regulator of thyroid function and growth, and is the key antigen in several pathological conditions including hyperthyroidism, hypothyroidism, and thyroid tumors. Various effective treatment strategies are currently available for many of these clinical conditions such as antithyroid drugs or radioiodine therapy, but they are not devoid of side effects. In addition, treatment of complications of Graves' disease such as Graves' ophthalmopathy is often difficult and unsatisfactory using current methods. Recent advances in basic research on both in vitro and in vivo models have suggested that TSH analogs could be used for diagnosis and treatment of some of the thyroid diseases. The advent of high-throughput screening methods has resulted in a group of TSH analogs called small molecules, which have the potential to be developed as promising drugs. Small molecules are low molecular weight compounds with agonist, antagonist and, in some cases, inverse agonist activity on TSHR. This short review will focus on current advances in development of TSH analogs and their potential clinical applications. Rapid advances in this field may lead to the conduct of clinical trials of small molecules related to TSHR for the management of Graves' disease, thyroid cancer, and thyroid-related osteoporosis in the coming years. Copyright © 2012 SEEN. Published by Elsevier Espana. All rights reserved.

  20. Significance of analog instrumentation - design philosophy of replacement dump arrest unit at Pickering Station Candu Reactor

    International Nuclear Information System (INIS)

    Miller, J.F.; McDowell, R.W.


    This paper discusses the differences of opinion concerning power plant instrumentation, including safety systems. One popular view point is that modem instrumentation must be microprocessor-based to be acceptable. An alternative view point is that properly designed analog instrumentation is recommended in some applications and has proven to be viable based upon performance and experience. A practical example is discussed in detail, explaining how a combination of discrete analog circuitry, combined with discrete digital circuitry provides a robust solution to a complex instrumentation replacement problem. In this application, a microprocessor-based instrument was designed as a replacement for an obsolete analog instrument. Due to severe licensing difficulties, the instrument was redesigned as a combination of discrete analog and digital circuitry. In the implementation of this circuitry, all complex testing functions of the improved microprocessor-based instrument were accommodated and system accuracy and performance were not compromised over the micro-processor-based instrument. The instrument has met all requirements for reliability and EMI/RFI susceptibility, as well as isolation of analog outputs and the ability to withstand severe transient noise on inputs and outputs without adversely affecting performance

  1. Principles for Integrating Mars Analog Science, Operations, and Technology Research (United States)

    Clancey, William J.


    During the Apollo program, the scientific community and NASA used terrestrial analog sites for understanding planetary features and for training astronauts to be scientists. Human factors studies (Harrison, Clearwater, & McKay 1991; Stuster 1996) have focused on the effects of isolation in extreme environments. More recently, with the advent of wireless computing, we have prototyped advanced EVA technologies for navigation, scheduling, and science data logging (Clancey 2002b; Clancey et al., in press). Combining these interests in a single expedition enables tremendous synergy and authenticity, as pioneered by Pascal Lee's Haughton-Mars Project (Lee 2001; Clancey 2000a) and the Mars Society s research stations on a crater rim on Devon Island in the High Canadian Arctic (Clancey 2000b; 2001b) and the Morrison Formation of southeast Utah (Clancey 2002a). Based on this experience, the following principles are proposed for conducting an integrated science, operations, and technology research program at analog sites: 1) Authentic work; 2) PI-based projects; 3) Unencumbered baseline studies; 4) Closed simulations; and 5) Observation and documentation. Following these principles, we have been integrating field science, operations research, and technology development at analog sites on Devon Island and in Utah over the past five years. Analytic methods include work practice simulation (Clancey 2002c; Sierhuis et a]., 2000a;b), by which the interaction of human behavior, facilities, geography, tools, and procedures are formalized in computer models. These models are then converted into the runtime EVA system we call mobile agents (Clancey 2002b; Clancey et al., in press). Furthermore, we have found that the Apollo Lunar Surface Journal (Jones, 1999) provides a vast repository or understanding astronaut and CapCom interactions, serving as a baseline for Mars operations and quickly highlighting opportunities for computer automation (Clancey, in press).

  2. Unconscious violinists and the use of analogies in moral argument (United States)

    Wiland, E.


    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. Key Words: Abortion • analogies • Thomson PMID:11129849

  3. Scientific Analogies and Their Use in Teaching Science (United States)

    Kipnis, Nahum

    Analogy in science knew its successes and failures, as illustrated by examples from the eighteenth-century physics. At times, some scientists abstained from using a certain analogy on the ground that it had not yet been demonstrated. Several false discoveries in the 18th and early 19th centuries appeared to support their caution. It is now clear that such a position reflected a methodological confusion that resulted from a failure to distinguish between particular and general analogies. Considering analogy as a hierarchical structure provides a new insight into "testing an analogy". While warning science teachers of dangers associated with use of analogy, historical cases and their analysis provided here may encourage them to use analogy more extensively while avoiding misconceptions. An argument is made that the history of science may be a better guide than philosophy of science and cognitive psychology when it concerns the role of analogy in science and in teaching science for understanding.

  4. Design, synthesis and antimicrobial evaluation of novel carbendazim dithioate analogs

    DEFF Research Database (Denmark)

    Zahran, Magdy A H; Osman, Amany M A; Wahed, Rania A.


    A novel series of carbendazim dithioate analogs was synthesized by the reaction of 2-aminobenzimdazole with CS2 and different alkyl halide in one pot reaction. All the chemical structure of carbendazim analogs were elucidated with all the spectroscopical tools IR, 1H, 13C NMR and mass-spectroscop......A novel series of carbendazim dithioate analogs was synthesized by the reaction of 2-aminobenzimdazole with CS2 and different alkyl halide in one pot reaction. All the chemical structure of carbendazim analogs were elucidated with all the spectroscopical tools IR, 1H, 13C NMR and mass...... against soil dehydrogenase activity. Among the carbendazim dithioates, some analogs were the most effective analogs against all the Gram-negative and positive-bacteria. While the most of them showed slight activities against Fusarium solani and Fusarium oxysporum. One of these analogs seemed to be more...... suppressive for dehydrogenase activity of soil microorganisms compared to all carbendazim sulfur analogs....

  5. Morphometry of Left Frontal and Temporal Poles Predicts Analogical Reasoning Abilities. (United States)

    Aichelburg, Clarisse; Urbanski, Marika; Thiebaut de Schotten, Michel; Humbert, Frederic; Levy, Richard; Volle, Emmanuelle


    Analogical reasoning is critical for making inferences and adapting to novelty. It can be studied experimentally using tasks that require creating similarities between situations or concepts, i.e., when their constituent elements share a similar organization or structure. Brain correlates of analogical reasoning have mostly been explored using functional imaging that has highlighted the involvement of the left rostrolateral prefrontal cortex (rlPFC) in healthy subjects. However, whether inter-individual variability in analogical reasoning ability in a healthy adult population is related to differences in brain architecture is unknown. We investigated this question by employing linear regression models of performance in analogy tasks and voxel-based morphometry in 54 healthy subjects. Our results revealed that the ability to reason by analogy was associated with structural variability in the left rlPFC and the anterior part of the inferolateral temporal cortex. Tractography of diffusion-weighted images suggested that these 2 regions have a different set of connections but may exchange information via the arcuate fasciculus. These results suggest that enhanced integrative and semantic abilities supported by structural variation in these areas (or their connectivity) may lead to more efficient analogical reasoning. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail:

  6. A Kolmogorov Complexity View of Analogy: From Logical Modeling to Experimentations (United States)

    Bayoudh, Meriam; Prade, Henri; Richard, Gilles

    Analogical reasoning is considered as one of the main mechanisms underlying human intelligence and creativity, allowing the paradigm shift essential to a creative process. More specific is the notion of analogical proportion like "2 is to 4 as 5 is to 10" or "read is to reader as lecture is to lecturer": such statements can be precisely described within an algebraic framework. When the proportion holds between concepts as in "engine is to car as heart is to human" or "wine is to France as beer is to England", applying an algebraic framework is less straightforward and a new way to understand analogical proportions on the basis of Kolmogorov complexity theory may seem more appropriate. This viewpoint has been used to develop a classifier detecting analogies in natural language. Despite their apparent difference, it is quite clear that the two viewpoints should be strongly related. In this paper, we investigate the link between a purely abstract view of analogical proportions and a definition based on Kolmogorov complexity theory. This theory is used as a backbone to experiment a classifier of natural language analogies whose results are consistent with the abstract setting.

  7. Functional DNA: Teaching Infinite Series through Genetic Analogy (United States)

    Kowalski, R. Travis


    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…


    Directory of Open Access Journals (Sweden)

    Ali Masyhar Mursyid


    Full Text Available The analogy becomes an absolute thing that is not permitted under the Indonesia criminal law. However, in the moving and changing society, written criminal laws are not always able to accommodate all the crime that happened. The prohibition of analogy it is not in line with Islamic law, “qiyas”, which no other is the analogy. Analogy should be accepted as part of a form of interpretation that has been known in the criminal law. Ban the use of analogy also confirmed in the draft Criminal Code. However, reading the ban of analogy must be done carefully.   Analogi menjadi satu hal mutlak yang tidak diperkenankan dalam hukum pidana. Namun demikian di tengah perkembangan masyarakat yang bergerak dan senantiasa berubah, perundang-undangan pidana tertulis tidak selamanya mampu menampung seluruh tindak pidana yang terjadi. Doktrin hukum pidana yang melarang analogi ini justru tidak sejalan dengan konsep hukum Islam yang mengenal qiyas, yang tiada lain adalah analogi. Seyogyanya analogi bisa diterima sebagai bagian dari bentuk penafsiran yang selama ini telah dikenal dalam hukum pidana. Larangan penggunaan analogi juga ditegaskan (kembali dalam Rancangan KUHP. Namun demikian perlu kehati-hatian dalam membaca larangan analogi dalam Rancangan KUHP ini.

  9. Investigating and Theorizing Discourse during Analogy Writing in Chemistry (United States)

    Bellocchi, Alberto; Ritchie, Stephen M.


    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…

  10. When Reasoning Modifies Memory: Schematic Assimilation Triggered by Analogical Mapping (United States)

    Vendetti, Michael S.; Wu, Aaron; Rowshanshad, Ebi; Knowlton, Barbara J.; Holyoak, Keith J.


    Analogical mapping highlights shared relations that link 2 situations, potentially at the expense of information that does not fit the dominant pattern of correspondences. To investigate whether analogical mapping can alter subsequent recognition memory for features of a source analog, we performed 2 experiments with 4-term proportional analogies…

  11. Analogies in Medicine: Valuable for Learning, Reasoning, Remembering and Naming (United States)

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


    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…

  12. Using Analogies as an Experiential Learning Technique in Multicultural Education (United States)

    Suthakaran, V.; Filsinger, Keri; White, Brittany


    In this article the authors specifically address the use of narratives in the form of analogies as an experiential learning activity. The use of analogies as an experiential learning tool in multicultural education can be helpful in a number of ways. Analogies provide an alternative tool for processing multicultural topics with students who have…

  13. Circuit with a successive approximation analog to digital converter

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten


    During successive approximation analog to digital conversion a series of successive digital reference values is selected that converges towards a digital representation of an analog input signal. An analog reference signal is generated dependent on the successive digital reference values and

  14. Circuit with a successive approximation analog to digital converter

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten


    During successive approximation analog to digital conversion a series of successive digital reference values is selected that converges towards a digital representation of an analog input signal. An analog reference signal is generated dependent on the successive digital reference values and

  15. Fluorescence resonance energy transfer of gas-phase ions under ultra high vacuum and ambient conditions. (United States)

    Frankevich, Vladimir; Chagovets, Vitaliy; Widjaja, Fanny; Barylyuk, Konstantin; Yang, Zhiyi; Zenobi, Renato


    We report evidence for fluorescence resonance energy transfer (FRET) of gas-phase ions under ultra high vacuum conditions (10(-9) mbar) inside a mass spectrometer as well as under ambient conditions inside an electrospray plume. Two different FRET pairs based on carboxyrhodamine 6G (donor) and ATTO590 or Bodipy TR (acceptor) dyes were examined and their gas-phase optical properties were studied. Our measurements indicate a different behavior for the two FRET pairs, which can be attributed to their different conformations in the gas phase. Upon desolvation via electrospray ionization, one of the FRET pairs undergoes a conformational change that leads to disappearance of FRET. This study shows the promise of FRET to obtain a direct correlation between solution and gas-phase structures.

  16. Conjecturing via analogical reasoning constructs ordinary students into like gifted student (United States)

    Supratman; Ratnaningsih, N.; Ryane, S.


    The purpose of this study is to reveal the development of knowledge of ordinary students to be like gifted students in the classroom based on Piaget's theory. In exposing it, students are given an open problem of classical analogy. Researchers explore students who conjecture via analogical reasoning in problem solving. Of the 32 students, through the method of think out loud and the interview was completed: 25 students conjecture via analogical reasoning. Of the 25 students, all of them have almost the same character in problem solving/knowledge construction. For that, a student is taken to analyze the thinking process while solving the problem/construction of knowledge based on Piaget's theory. Based on Piaget's theory in the development of the same knowledge, gifted students and ordinary students have similar structures in final equilibrium. They begin processing: assimilation and accommodation of problem, strategies, and relationships.

  17. SSERVI Analog Regolith Simulant Testbed Facility (United States)

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


    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

  18. High fluid intelligence and analogical reasoning


    Preusse, Franziska


    Hitherto, previous studies on the cerebral correlates of fluid intelligence (fluIQ) used tasks that did not exclusively demand fluIQ, or were restricted to participants of average fluIQ (ave-fluIQ) solving intelligence test items of varying difficulty, thus not allowing assumptions on interindividual differences in fluIQ. Geometric analogical reasoning (GAR) demands fluIQ very purely and thus is an eligible approach for research on interindividual differences in fluIQ. In a first study, we ...

  19. Analog to digital conversion for nuclear spectrometry

    International Nuclear Information System (INIS)

    Carvalho, P.V.R. de.


    A study of the analog to digital conversion techniques for nuclear spectrometry is presented and the main design philosophies of nuclear ADC's are compared. Among them, the most suitable for the current Brazilian conditions, concerning the specifications and components avaiability is the one that employs a statistical correction of successive approximation converters. This technique is described in full detail. A prototype has been developed an tested for the practical demonstration of the theoretical conclusions. These tests was carried on nuclear spectrometry data aquisition system whose implementation is also described. (Author) [pt

  20. A bilateral frontoparietal network underlies visuospatial analogical reasoning. (United States)

    Watson, Christine E; Chatterjee, Anjan


    Our ability to reason by analogy facilitates problem solving and allows us to communicate ideas efficiently. In this study, we examined the neural correlates of analogical reasoning and, more specifically, the contribution of rostrolateral prefrontal cortex (RLPFC) to reasoning. This area of the brain has been hypothesized to integrate relational information, as in analogy, or the outcomes of subgoals, as in multi-tasking and complex problem solving. Using fMRI, we compared visuospatial analogical reasoning to a control task that was as complex and difficult as the analogies and required the coordination of subgoals but not the integration of relations. We found that analogical reasoning more strongly activated bilateral RLPFC, suggesting that anterior prefrontal cortex is preferentially recruited by the integration of relational knowledge. Consistent with the need for inhibition during analogy, bilateral, and particularly right, inferior frontal gyri were also more active during analogy. Finally, greater activity in bilateral inferior parietal cortex during the analogy task is consistent with recent evidence for the neural basis of spatial relation knowledge. Together, these findings indicate that a network of frontoparietal areas underlies analogical reasoning; we also suggest that hemispheric differences may emerge depending on the visuospatial or verbal/semantic nature of the analogies. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Elucidating the neurotoxic effects of MDMA and its analogs. (United States)

    Karuppagounder, Senthilkumar S; Bhattacharya, Dwipayan; Ahuja, Manuj; Suppiramaniam, Vishnu; Deruiter, Jack; Clark, Randall; Dhanasekaran, Muralikrishnan


    There is a rapid increase in the use of methylenedioxymethamphetamine (MDMA) and its structural congeners/analogs globally. MDMA and MDMA-analogs have been synthesized illegally in furtive dwellings and are abused due to its addictive potential. Furthermore, MDMA and MDMA-analogs have shown to have induced several adverse effects. Hence, understanding the mechanisms mediating this neurotoxic insult of MDMA-analogs is of immense importance for the public health in the world. We synthesized and investigated the neurotoxic effects of MDMA and its analogs [4-methylenedioxyamphetamine (MDA), 2, 6-methylenedioxyamphetamine (MDMA), and N-ethyl-3, 4-methylenedioxyamphetamine (MDEA)]. The stimulatory or the dopaminergic agonist effects of MDMA and MDMA-analogs were elucidated using the established 6-hydroxydopamine lesioned animal model. Additionally, we also investigated the neurotoxic mechanisms of MDMA and MDMA-analogs on mitochondrial complex-I activity and reactive oxygen species generation. MDMA and MDMA-analogs exhibited stimulatory activity as compared to amphetamines and also induced several behavioral changes in the rodents. MDMA and MDMA-analogs enhanced the reactive oxygen generation and inhibited mitochondrial complex-I activity which can lead to neurodegeneration. Hence the mechanism of neurotoxicity, MDMA and MDMA-analogs can enhance the release of monoamines, alter the monoaminergic neurotransmission, and augment oxidative stress and mitochondrial abnormalities leading to neurotoxicity. Thus, our study will help in developing effective pharmacological and therapeutic approaches for the treatment of MDMA and MDMA-analog abuse. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Noah D. Finkelstein


    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.

  3. How the creative use of analogies can shape medical practice. (United States)

    Prasad, G V Ramesh


    Analogical reasoning is central to medical progress, and is either creative or conservative. According to Hofmann et al., conservative analogy relates concepts from old technology to new technologies with emphasis on preservation of comprehension and conduct. Creative analogy however brings new understanding to new technology, brings similarities existing in the source domain to a target domain where they previously had no bearing, and imports something entirely different from the content of the analogy itself. I defend the claim that while conservative analogies are useful by virtue of being comfortable to use from familiarity and experience, and are more easily accepted by society, they only lead to incremental advances in medicine. However, creative analogies are more exciting and productive because they generate previously unexpected associations across widely separated domains, emphasize relations over physical similarities, and structure over superficiality. I use kidney transplantation and anti-rejection medication development as an exemplar of analogical reasoning used to improve medical practice. Anti-rejection medication has not helped highly sensitized patients because of their propensity to rejecting most organs. I outline how conservative analogical reasoning led to anti-rejection medication development, but creative analogical reasoning helped highly sensitized and blood type incompatible patients through domino transplants, by which they obtain a kidney to which they are not sensitized. Creative analogical reasoning is more likely than conservative analogical reasoning to lead to revolutionary progress. While these analogies overlap and creative analogies eventually become conservative, progress is best facilitated by combining conservative and creative analogical reasoning. © 2015 John Wiley & Sons, Ltd.

  4. Menaquinone analogs inhibit growth of bacterial pathogens. (United States)

    Schlievert, Patrick M; Merriman, Joseph A; Salgado-Pabón, Wilmara; Mueller, Elizabeth A; Spaulding, Adam R; Vu, Bao G; Chuang-Smith, Olivia N; Kohler, Petra L; Kirby, John R


    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.

  5. Palytoxin and Analogs: Biological and Ecological Effects

    Directory of Open Access Journals (Sweden)

    Vítor Ramos


    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. Merging Galaxy Clusters: Analysis of Simulated Analogs (United States)

    Nguyen, Jayke; Wittman, David; Cornell, Hunter


    The nature of dark matter can be better constrained by observing merging galaxy clusters. However, uncertainty in the viewing angle leads to uncertainty in dynamical quantities such as 3-d velocities, 3-d separations, and time since pericenter. The classic timing argument links these quantities via equations of motion, but neglects effects of nonzero impact parameter (i.e. it assumes velocities are parallel to the separation vector), dynamical friction, substructure, and larger-scale environment. We present a new approach using n-body cosmological simulations that naturally incorporate these effects. By uniformly sampling viewing angles about simulated cluster analogs, we see projected merger parameters in the many possible configurations of a given cluster. We select comparable simulated analogs and evaluate the likelihood of particular merger parameters as a function of viewing angle. We present viewing angle constraints for a sample of observed mergers including the Bullet cluster and El Gordo, and show that the separation vectors are closer to the plane of the sky than previously reported.

  7. Comparison between analog and digital filters

    Directory of Open Access Journals (Sweden)

    Zoltan Erdei


    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.

  8. AFEII Analog Front End Board Design Specifications

    Energy Technology Data Exchange (ETDEWEB)

    Rubinov, Paul; /Fermilab


    This document describes the design of the 2nd iteration of the Analog Front End Board (AFEII), which has the function of receiving charge signals from the Central Fiber Tracker (CFT) and providing digital hit pattern and charge amplitude information from those charge signals. This second iteration is intended to address limitations of the current AFE (referred to as AFEI in this document). These limitations become increasingly deleterious to the performance of the Central Fiber Tracker as instantaneous luminosity increases. The limitations are inherent in the design of the key front end chips on the AFEI board (the SVXIIe and the SIFT) and the architecture of the board itself. The key limitations of the AFEI are: (1) SVX saturation; (2) Discriminator to analog readout cross talk; (3) Tick to tick pedestal variation; and (4) Channel to channel pedestal variation. The new version of the AFE board, AFEII, addresses these limitations by use of a new chip, the TriP-t and by architectural changes, while retaining the well understood and desirable features of the AFEI board.

  9. Endpoint distinctiveness facilitates analogical mapping in pigeons. (United States)

    Hagmann, Carl Erick; Cook, Robert G


    Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due to endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal mapping of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons' capacity for more advanced types of analogical reasoning. This article is part of a Special Issue entitled: Tribute to Tom Zentall. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Endpoint Distinctiveness Facilitates Analogical Mapping in Pigeons (United States)

    Hagmann, Carl Erick; Cook, Robert G.


    Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, reassignment, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal map of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons’ capacity for more advanced types of analogical reasoning. PMID:25447511

  11. Metastatic Insulinoma Managed with Radiolabeled Somatostatin Analog

    Directory of Open Access Journals (Sweden)

    Ricardo Costa


    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.

  12. Developing Fluorescent Hyaluronan Analogs for Hyaluronan Studies

    Directory of Open Access Journals (Sweden)

    Shi Ke


    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. Electrochemical Bioelectronic Device Consisting of Metalloprotein for Analog Decision Making (United States)

    Chung, Yong-Ho; Lee, Taek; Yoo, Si-Youl; Min, Junhong; Choi, Jeong-Woo


    We demonstrate an analog type logical device that combines metalloprotein and organic/inorganic materials and can make an interactive analog decision. Myoglobin is used as a functional biomolecule to generate electrochemical signals, and its original redox signal is controlled with various mercapto-acids by the distance effect between myoglobin and a metal surface in the process of electron transfer. Controlled signals are modulated with the introduction of inorganic materials including nanoparticles and metal ions. By forming a hybrid structure with various constituents of organic/inorganic materials, several functions for signal manipulation were achieved, including enhancement, suppression, and shift. Based on the manipulated signals of biomolecules, a novel logical system for interactive decision-making processes is proposed by selectively combining different signals. Through the arrangement of various output signals, we can define interactive logical results regulated by an inherent tendency (by metalloprotein), personal experience (by organic spacer sets), and environments (by inorganic materials). As a practical application, a group decision process is presented using the proposed logical device. The proposed flexible logic process could facilitate the realization of an artificial intelligence system by mimicking the sophisticated human logic process.

  14. Programmable electronic system for analog and digital gamma cameras modernization

    International Nuclear Information System (INIS)

    Osorio Deliz, J. F.; Diaz Garcia, A.; Arista Omeu, E. J.


    At present the use of analog and digital gamma cameras is continuously increasing in developing countries. Many of them still largely rely in old hardware electronics, which in many cases limits their use in actual nuclear medicine diagnostic studies. For this reason worldwide there are different medical equipment manufacturing companies engaged into partial or total Gamma Cameras modernization. Nevertheless in several occasions acquisition prices are not affordable for developing countries. This work describes the basic features of a programmable electronic system that allows improving acquisitions functions and processing of analog and digital gamma cameras. This system is based on an electronic board for the acquisition and digitization of nuclear pulses which have been generated by gamma camera detector. It comprises a hardware interface with PC and the associated software to fully signal processing. Signal shaping and image processing are included. The extensive use of reference tables in the processing and signal imaging software allowed the optimization of the processing speed. Time design and system cost were also decreased. (Author)

  15. Shifting the Frontiers of Analog and Mixed-Signal Electronics

    Directory of Open Access Journals (Sweden)

    Arthur H. M. van Roermund


    Full Text Available Nowadays, analog and mixed-signal (AMS IC designs, mainly found in the frontends of large ICs, are highly dedicated, complex, and costly. They form a bottleneck in the communication with the outside world, determine an upper bound in quality, yield, and flexibility for the IC, and require a significant part of the power dissipation. Operating very close to physical limits, serious boundaries are faced. This paper relates, from a high-level point of view, these boundaries to the Shannon channel capacity and shows how the AMS circuitry forms a matching link in transforming the external analog signals, optimized for the communication medium, to the optimal on-chip signal representation, the digital one, for the IC medium. The signals in the AMS part itself are consequently not optimally matched to the IC medium. To further shift the frontiers of AMS design, a matching-driven design approach is crucial for AMS. Four levels will be addressed: technology-driven, states-driven, redundancy-driven, and nature-driven design. This is done based on an analysis of the various classes of AMS signals and their specific properties, seen from the angle of redundancy. This generic, but abstract way of looking at the design process will be substantiated with many specific examples.

  16. Nitazoxanide Analogs Require Nitroreduction for Antimicrobial Activity in Mycobacterium smegmatis. (United States)

    Buchieri, Maria V; Cimino, Mena; Rebollo-Ramirez, Sonia; Beauvineau, Claire; Cascioferro, Alessandro; Favre-Rochex, Sandrine; Helynck, Olivier; Naud-Martin, Delphine; Larrouy-Maumus, Gerald; Munier-Lehmann, Hélène; Gicquel, Brigitte


    In this study, we aimed to decipher the natural resistance mechanisms of mycobacteria against novel compounds isolated by whole-cell-based high-throughput screening (HTS). We identified active compounds using Mycobacterium aurum. Further analyses were performed to determine the resistance mechanism of M. smegmatis against one hit, 3-bromo-N-(5-nitrothiazol-2-yl)-4-propoxybenzamide (3), which turned out to be an analog of the drug nitazoxanide (1). We found that the repression of the gene nfnB coding for the nitroreductase NfnB was responsible for the natural resistance of M. smegmatis against 3. The overexpression of nfnB resulted in sensitivity of M. smegmatis to 3. This compound must be metabolized into hydroxylamine intermediate for exhibiting antibacterial activity. Thus, we describe, for the first time, the activity of a mycobacterial nitroreductase against 1 analogs, highlighting the differences in the metabolism of nitro compounds among mycobacterial species and emphasizing the potential of nitro drugs as antibacterials in various bacterial species.

  17. Design rules for superconducting analog-digital transducers

    International Nuclear Information System (INIS)

    Haddad, Taghrid


    This Thesis is a contribution for dimensioning aspects of circuits designs in superconductor electronics. Mainly superconductor comparators inclusive Josephson comparators as well as QOJS-Comparators are investigated. Both types were investigated in terms of speed and sensitivity. The influence of the thermal noise on the decision process of the comparators represent in so called gray zone, which is analysed in this thesis. Thereby, different relations between design parameters were derived. A circuit model of the Josephson comparator was verified by experiments. Concepts of superconductor analog-to-digital converters, which are based on above called comparators, were investigated in detail. From the comparator design rules, new rules for AD-converters were derived. Because of the reduced switching energy, the signal to noise ratio (SNR) of the circuits is affected and therefore the reliability of the decision-process is affected. For special applications with very demanding requirements in terms of the speed and accuracy superconductor analog-to-digital converters offer an excellent performance. This thesis provides relations between different design paramenters and shows resulting trade-offs, This method is transparent and easy to transfer to other circuit topologies. As a main result, a highly predictive tool for dimensioning of superconducting ADC's is proved.

  18. Precipitation forecasting through an analog sorting technique: a comparative study (United States)

    Ben Daoud, A.; Sauquet, E.; Lang, M.; Bontron, G.; Obled, C.


    This study aims at comparing two quantitative precipitation forecasting techniques based on the meteorological analogy concept. Method A considers first a selection of analogous situations at synoptic scale. Second a subset of the most similar situations in terms of hygrometry is extracted. Method B extends method A by two innovative ways, which are restricting the search for analogues with temperature information instead of the common season criterion, and exploiting the information about vertical motion considering vertical velocity. Forecasts are evaluated in a perfect prognosis context and in operational conditions as well, by mean of verification measures (Continuous Ranked Probability Skill Score and scores computed from contingency tables). Results of the case study in France show that: (1) there is an increase in forecast skill when temperature and vertical velocity are included in the procedure, (2) it is possible to anticipate rainfall events up to one week ahead and (3) the introduction of new variables such as vertical velocity may be useless beyond few days ahead if the forecast of the weather model is not reliable.

  19. Energy Savings Assessment for Digital-to-Analog Converter Boxes

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Hoi Ying Iris; Meier, Alan; Brown, Richard


    The Digital Television (DTV) Converter Box Coupon Program was administered by the U.S. government to subsidize purchases of digital-to-analog converter boxes, with up to two $40 coupons for each eligible household. In order to qualify as Coupon Eligible Converter Boxes (CECBs), these devices had to meet a number of minimum performance specifications, including energy efficiency standards. The Energy Star Program also established voluntary energy efficiency specifications that are more stringent than the CECB requirements. In this study, we measured the power and energy consumptions for a sample of 12 CECBs (including 6 Energy Star labeled models) in-use in homes and estimated aggregate energy savings produced by the energy efficiency policies. Based on the 35 million coupons redeemed through the end of the program, our analysis indicates that between 2500 and 3700 GWh per year are saved as a result of the energy efficiency policies implemented on digital-to-analog converter boxes. The energy savings generated are equivalent to the annual electricity use of 280,000 average US homes.

  20. Terrestrial analogs, planetary geology, and the nature of geological reasoning (United States)

    Baker, Victor R.


    Analogical reasoning is critical to planetary geology, but its role can be misconstrued by those unfamiliar with the practice of that science. The methodological importance of analogy to geology lies in the formulation of genetic hypotheses, an absolutely essential component of geological reasoning that was either ignored or denigrated by most 20th century philosophers of science, who took the theoretical/ experimental methodology of physics to be the sole model for all of scientific inquiry. Following the seminal 19th century work of Grove Karl Gilbert, an early pioneer of planetary geology, it has long been recognized that broad experience with and understanding of terrestrial geological phenomena provide geologists with their most effective resource for the invention of potentially fruitful, working hypotheses. The actions of (1) forming such hypotheses, (2) following their consequences, and (3) testing those consequences comprise integral parts of effective geological practice in regard to the understanding of planetary surfaces. Nevertheless, the logical terminology and philosophical bases for such practice will be unfamiliar to most planetary scientists, both geologists and nongeologists. The invention of geological hypotheses involves both inductive inferences of the type Gilbert termed “empiric classification” and abductive inferences of a logical form made famous by the 19th century American logician Charles Sanders Peirce. The testing and corroboration of geological hypotheses relies less on the correspondence logic of theoretical/ experimental sciences, like physics, and more on the logic of consistency, coherence, and consilience that characterizes the investigative and historical sciences of interpretation exemplified by geology.

  1. Dimensional analysis, similarity, analogy, and the simulation theory

    International Nuclear Information System (INIS)

    Davis, A.A.


    Dimensional analysis, similarity, analogy, and cybernetics are shown to be four consecutive steps in application of the simulation theory. This paper introduces the classes of phenomena which follow the same formal mathematical equations as models of the natural laws and the interior sphere of restraints groups of phenomena in which one can introduce simplfied nondimensional mathematical equations. The simulation by similarity in a specific field of physics, by analogy in two or more different fields of physics, and by cybernetics in nature in two or more fields of mathematics, physics, biology, economics, politics, sociology, etc., appears as a unique theory which permits one to transport the results of experiments from the models, convenably selected to meet the conditions of researches, constructions, and measurements in the laboratories to the originals which are the primary objectives of the researches. Some interesting conclusions which cannot be avoided in the use of simplified nondimensional mathematical equations as models of natural laws are presented. Interesting limitations on the use of simulation theory based on assumed simplifications are recognized. This paper shows as necessary, in scientific research, that one write mathematical models of general laws which will be applied to nature in its entirety. The paper proposes the extent of the second law of thermodynamics as the generalized law of entropy to model life and its activities. This paper shows that the physical studies and philosophical interpretations of phenomena and natural laws cannot be separated in scientific work; they are interconnected and one cannot be put above the others

  2. Use of antarctic analogs to support the space exploration initiative (United States)

    Wharton, Robert; Roberts, Barney; Chiang, Erick; Lynch, John; Roberts, Carol; Buoni, Corinne; Andersen, Dale


    This report has discussed the Space Exploration Initiative (SEI) and the U.S. Antarctic Program (USAP) in the context of assessing the potential rationale and strategy for conducting a cooperative NASA/NSF (National Science Foundation) effort. Specifically, such an effort would address shared research and data on living and conducting scientific research in isolated, confined, hostile, and remote environments. A review of the respective goals and requirements of NASA and the NSF indicates that numerous opportunities exist to mutually benefit from sharing relevant technologies, data, and systems. Two major conclusions can be drawn: (1) The technologies, experience, and capabilities existing and developing in the aerospace community would enhance scientific research capabilities and the efficiency and effectiveness of operations in Antarctica. The transfer and application of critical technologies (e.g., power, waste management, life support) and collaboration on crew research needs (e.g., human behavior and medical support needs) would streamline the USAP operations and provide the scientific community with advancements in facilities and tools for Antarctic research. (2) Antarctica is the most appropriate earth analog for the environments of the the Moon and Mars. Using Antarctica in this way would contribute substantially to near- and long-term needs and plans for the SEI. Antarctica is one of the few ground-based analogs that would permit comprehensive and integrated studies of three areas deemed critical to productive and safe operations on the Moon and Mars: human health and productivity; innovative scientific research techniques; and reliable, efficient technologies and facilities.

  3. 2-acetylphenol analogs as potent reversible monoamine oxidase inhibitors

    Directory of Open Access Journals (Sweden)

    Legoabe LJ


    Full Text Available Lesetja J Legoabe,1 Anél Petzer,1 Jacobus P Petzer1,21Centre of Excellence for Pharmaceutical Sciences, 2Department of Pharmaceutical Chemistry, School of Pharmacy, North-West University, Potchefstroom, South AfricaAbstract: Based on a previous report that substituted 2-acetylphenols may be promising leads for the design of novel monoamine oxidase (MAO inhibitors, a series of C5-substituted 2-acetylphenol analogs (15 and related compounds (two were synthesized and evaluated as inhibitors of human MAO-A and MAO-B. Generally, the study compounds exhibited inhibitory activities against both MAO-A and MAO-B, with selectivity for the B isoform. Among the compounds evaluated, seven compounds exhibited IC50 values <0.01 µM for MAO-B inhibition, with the most selective compound being 17,000-fold selective for MAO-B over the MAO-A isoform. Analyses of the structure–activity relationships for MAO inhibition show that substitution on the C5 position of the 2-acetylphenol moiety is a requirement for MAO-B inhibition, and the benzyloxy substituent is particularly favorable in this regard. This study concludes that C5-substituted 2-acetylphenol analogs are potent and selective MAO-B inhibitors, appropriate for the design of therapies for neurodegenerative disorders such as Parkinson’s disease.Keywords: monoamine oxidase, MAO, inhibition, 2-acetylphenol, structure–activity relationship

  4. Thermoelectricity analogy method for computing the periodic heat transfer in external building envelopes

    International Nuclear Information System (INIS)

    Peng Changhai; Wu Zhishen


    Simple and effective computation methods are needed to calculate energy efficiency in buildings for building thermal comfort and HVAC system simulations. This paper, which is based upon the theory of thermoelectricity analogy, develops a new harmonic method, the thermoelectricity analogy method (TEAM), to compute the periodic heat transfer in external building envelopes (EBE). It presents, in detail, the principles and specific techniques of TEAM to calculate both the decay rates and time lags of EBE. First, a set of linear equations is established using the theory of thermoelectricity analogy. Second, the temperature of each node is calculated by solving the linear equations set. Finally, decay rates and time lags are found by solving simple mathematical expressions. Comparisons show that this method is highly accurate and efficient. Moreover, relative to the existing harmonic methods, which are based on the classical control theory and the method of separation of variables, TEAM does not require complicated derivation and is amenable to hand computation and programming

  5. Relating derived relations as a model of analogical reasoning: reaction times and event-related potentials. (United States)

    Barnes-Holmes, Dermot; Regan, Donal; Barnes-Holmes, Yvonne; Commins, Sean; Walsh, Derek; Stewart, Ian; Smeets, Paul M; Whelan, Robert; Dymond, Simon


    The current study aimed to test a Relational Frame Theory (RFT) model of analogical reasoning based on the relating of derived same and derived difference relations. Experiment 1 recorded reaction time measures of similar-similar (e.g., "apple is to orange as dog is to cat") versus different-different (e.g., "he is to his brother as chalk is to cheese") derived relational responding, in both speed-contingent and speed-noncontingent conditions. Experiment 2 examined the event-related potentials (ERPs) associated with these two response patterns. Both experiments showed similar-similar responding to be significantly faster than different-different responding. Experiment 2 revealed significant differences between the waveforms of the two response patterns in the left-hemispheric prefrontal regions; different-different waveforms were significantly more negative than similar-similar waveforms. The behavioral and neurophysiological data support the RFT prediction that, all things being equal, similar-similar responding is relationally "simpler" than, and functionally distinct from, different-different analogical responding. The ERP data were fully consistent with findings in the neurocognitive literature on analogy. These findings strengthen the validity of the RFT model of analogical reasoning and supplement the behavior-analytic approach to analogy based on the relating of derived relations.

  6. Karakteristik Beras Analog Berindeks Glisemik Rendah dari Oyek dengan Penambahan Berbagai Jenis Kacang-Kacangan

    Directory of Open Access Journals (Sweden)

    Bayu Kanetro


    Full Text Available The aim of this research was to determine the best legumes for increasing protein of artificial rice that was made of dried growol or oyek based on physical, sensory charactersitics and glycemic index. The experiment design of this research was randomized complete design with the single factor of legumes type, that were soybean mungbean, vevet bean, and cowpeas. The first step of artificial rice processing was mixing dried oyek and legumes flour with 3:7 ratio. The next step was forming the dough into the same as rice, steaming, and drying for producing artificial rice that could be stored. The products of artificial rice were analyzed for texture, colour, and preference level of dried and steamed procuct, proximate composition of dried product, and glycemic index (IG of steamed product. The result of this research showed that the type of legumes affected the physical and sensory characteristic of artificial rice. The best legumes for producing artificial rice was mungbean. The preference level of the best product was better than the other legumes, and the same as original rice. The proximate composition especially protein content of the best product was the same as original rice, and its IG was be categorized in low IG food product. ABSTRAK   Penelitian ini bertujuan menentukan jenis kacang-kacangan yang tepat untuk meningkatkan kadar protein beras analog dari growol kering atau oyek berdasarkan sifat fisik, kimia, sensoris, dan indeks glisemik. Penelitian dilaksanakan dengan rancangan acak lengkap faktor tunggal yaitu jenis kacang-kacangan yang meliputi kacang kedelai, tunggak, koro, dan kacang hijau. Beras analog/artificial dibuat melalui tahap pembuatan adonan yang terdiri campuran tepung kacang-kacangan dan tepung oyek dengan perbandingan 3:7. Selanjutnya dibentuk menyerupai beras, dikukus, dan dikeringkan sehingga diperoleh beras analog yang dapat disimpan. Produk kering dan produk yang siap dikonsumsi (nasi analog selanjutnya dianalisis

  7. A synthetic combinatorial strategy for developing a-conotoxin analogs as potent a7 nicotinic acetylcholine receptor antagonists

    DEFF Research Database (Denmark)

    Armishaw, Christopher J; Singh, Narender; Medina-Franco, Jose L


    ) nAChR Fluo-4/Ca2+ assay, allowing amino acids that confer antagonistic activity for this receptor to be identified. A second series of individual alpha-conotoxin analogs based on the combinations of defined active amino acid residues from positional scan synthetic combinatorial library screening...... of an acetylcholine-binding protein. Finally, a third series of refined analogs was synthesized based on modeling studies, which led to several analogs with refined pharmacological properties. Of the 96 individual alpha-conotoxin analogs synthesized, three displayed > or =10-fold increases in antagonist potency...

  8. Synthetic Biology: A Unifying View and Review Using Analog Circuits. (United States)

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


    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. The development of analogical reasoning in deaf children and their parents' communication mode. (United States)

    Bandurski, Marcin; Galkowski, Tadeusz


    The purpose of this article is to analyze the results of a study of the development of analogical reasoning in deaf children coming from two different linguistic environments (deaf children of deaf parents--sign language, deaf children of hearing parents--spoken language) and in hearing children, as well as to compare two groups of deaf children to a group of hearing children. In order to estimate the development of children's analogical reasoning, especially the development of their understanding of different logical relations, two age groups were singled out in each population of children: younger (9- and 10-year-olds) and older (12- and 13-year-olds). In this way it is possible to assess the influence of early and consistent sign-language communication on the development of the conceptual system in deaf children and to establish whether early and consistent sign-language communication with deaf children affects their mental development to the same extent as early and consistent spoken-language communication with hearing children. The children were given three series of analogy tasks based on different logical relations: (a) a series of verbal analogy tasks (the relations of opposite, part-whole, and causality); (b) a series of numerical analogy tasks (the relations of class membership, opposite, and part-whole); and (c) a series of figural-geometric analogy tasks (the relations of opposite and part-whole). It was found that early and consistent sign-language communication with deaf children plays an almost equivalent role in the development of verbal, numerical, and spatial reasoning by analogy as early and consistent spoken-language communication with hearing children.

  10. Analog Memristive Synapse in Spiking Networks Implementing Unsupervised Learning (United States)

    Covi, Erika; Brivio, Stefano; Serb, Alexander; Prodromakis, Themis; Fanciulli, Marco; Spiga, Sabina


    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 images are displayed and it is robust to a device-to-device variability of up to ±30%. PMID:27826226

  11. Atwood and Poggendorff: an insightful analogy

    DEFF Research Database (Denmark)

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


    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......- 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....

  12. Analog VLSI system for active drag reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, B.; Goodman, R.; Jiang, F.; Tai, Y.C. [California Inst. of Technology, Pasadena, CA (United States); Tung, S.; Ho, C.M. [Univ. of California, Los Angeles, CA (United States)


    In today`s cost-conscious air transportation industry, fuel costs are a substantial economic concern. Drag reduction is an important way to reduce costs. Even a 5% reduction in drag translates into estimated savings of millions of dollars in fuel costs. Drawing inspiration from the structure of shark skin, the authors are building a system to reduce drag along a surface. Our analog VLSI system interfaces with microfabricated, constant-temperature shear stress sensors. It detects regions of high shear stress and outputs a control signal to activate a microactuator. We are in the process of verifying the actual drag reduction by controlling microactuators in wind tunnel experiments. We are encouraged that an approach similar to one that biology employs provides a very useful contribution to the problem of drag reduction. 9 refs., 21 figs.

  13. Four-gate transistor analog multiplier circuit (United States)

    Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)


    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.

  14. Analog Electronic Filters Theory, Design and Synthesis

    CERN Document Server

    Dimopoulos, Hercules G


    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...

  15. Atwood and Poggendorff: an insightful analogy (United States)

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


    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.

  16. READ - Remote Analog ASIC Design System

    Directory of Open Access Journals (Sweden)

    Michael E. Auer


    Full Text Available The scope of this work is to present a solution to implement a remote electronic laboratory for testing and designing analog ASICs (ispPAC10. The application allows users to create circuit schematics, upload the design to the device and perform measurements. The software used for designing circuits is the PAC-Designer and it runs on a Citrix server. The signals are generated and the responses are acquired by a data acquisition board controlled by LabView. The virtual instruments interact with some ActiveX controls specially designed to look like real oscilloscope and function generator devices and represent the user interface of the lab. These ActiveX give users the control over the LabView VIs and the access to its facilities in order to perform electronic exercises.

  17. Antifungal Activity of Homoaconitate and Homoisocitrate Analogs

    Directory of Open Access Journals (Sweden)

    Sławomir Milewski


    Full Text Available Thirteen structural analogs of two initial intermediates of the L-a-aminoadipate pathway of L-lysine biosynthesis in fungi have been designed and synthesized, including fluoro- and epoxy-derivatives of homoaconitate and homoisocitrate. Some of the obtained compounds exhibited at milimolar range moderate enzyme inhibitory properties against homoaconitase and/or homoisocitrate dehydrogenase of Candida albicans. The structural basis for homoisocitrate dehydrogenase inhibition was revealed by molecular modeling of the enzyme-inhibitor complex. On the other hand, the trimethyl ester forms of some of the novel compounds exhibited antifungal effects. The highest antifungal activity was found for trimethyl trans-homoaconitate, which inhibited growth of some human pathogenic yeasts with minimal inhibitory concentration (MIC values of 16–32 mg/mL.

  18. 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


    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.

  19. Synthetic analogs of bacterial quorum sensors

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Rashi S.; Ganguly, Kumkum; Silks, Louis A.


    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.

  20. Detector Readout of Analog Quantum Simulators (United States)

    Schwenk, Iris; Tian, Lin; Marthaler, Michael

    An important step in quantum simulation is to measure the many-body correlations of the simulated model. For a practical quantum simulator composed of a finite number of qubits and cavities, in contrast to many-body systems in the thermodynamic limit, a measurement device can generate strong backaction on the simulator, which could prevent the accurate readout of the correlation functions. Here we calculate the readout of a detector coupled to analog quantum simulators. We show that reliable characterization of the many-body correlations of the simulators can be achieved when the coupling operators obey the Wick's theorem. Our results are illustrated with two examples: a simulator for an harmonic oscillator and a simulator for the free electron gas. We also present a method, which under certain constraints, allows for the reconstruction of the ideal correlators from the measurements on a perturbed quantum simulator. This work is in part supported by the National Science Foundation under Award Number 0956064.

  1. Integrated Circuits for Analog Signal Processing

    CERN Document Server


      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...

  2. Natural analogs in support of the Canadian concept for nuclear fuel waste disposal

    International Nuclear Information System (INIS)

    Cramer, Jan.


    The assessment of the long-term safety and performance of the Canadian concept for disposal of nuclear fuel waste is a unique and challenging undertaking, because the predictions have to be made for time periods in the range of 10 4 to 10 6 a into the future. The data used for the assessment modelling is in large part based on observations from short-term laboratory and field experiments. Natural analogs can provide a reference for the safety assessment, providing both useful data and a qualitative illustration of the interaction of processes and materials in complex natural systems. This report reviews the available natural analog information used in support of the Canadian concept, with particular emphasis on the disposal of used CANDU (CANada Deuterium Uranium) fuel. The introduction gives a definition of natural analogs and an overview of the various types of analogs and analog studies. The review is broken down into sections pertaining to the major components of the disposal system: the vault, the geosphere and the biosphere. Specific examples are given for each. In addition, a section deals with several comprehensive natural systems that contain a number of features and processes similar to the disposal concept and that are under study by a number of countries as part of their waste management programs. (author). 224 refs., 11 tabs., 2 figs

  3. Analogies between classical statistical mechanics and quantum mechanics

    International Nuclear Information System (INIS)

    Uehara, M.


    Some analogies between nonequilibrium classical statistical mechanics and quantum mechanics, at the level of the Liouville equation and at the kinetic level, are commented on. A theorem, related to the Vlasov equation applied to a plasma, is proved. The theorem presents an analogy with Ehrenfest's theorem of quantum mechanics. An analogy between the plasma kinetic theory and Bohm's quantum theory with 'hidden variables' is also shown. (Author) [pt

  4. The analogic model ''RIC'' of thermal behaviour of mass concrete

    International Nuclear Information System (INIS)

    Gonzalez Redondo, M.; Gonzalez de Posada, F.; Plana Claver, J.


    In order to study the thermal field and calorific flows in heat sources (i.e. mass concrete during setting) we have conceived, built and experimented with an analogical electric model. This model, named RIC, consists of resistors (R) and capacitors (C) in which nodes an electric current (I) has been injected. Several analogical constants were used for the mathematical approximation. Thus, this paper describes the analogical RIC model, simulating heat generation, boundary and initial conditions and concreting. (Author) 4 refs

  5. Synthesis and anti-inflammatory activity of phenylbutenoid dimer analogs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Soo; Fang, Yuan Ying; Park, Hae Eil [Kangwon National University, Chuncheon (Korea, Republic of)


    Several phenylbutenoid dimer (PBD) analogs were synthesized and evaluated for their inhibitory activities against nitric oxide (NO) production and TNF-α release. The PBD analogs were synthesized via Diels–Alder and subsequent Schlosser reactions as key steps. Among the tested compounds, two analogs (8c, 8f) exhibited much stronger inhibitory activity against LPS-stimulated NO production and TNF-α release in RAW 264.7 cells than that of wogonin.

  6. Inferring principles for sustainable development of business through analogies from ecological systems

    Directory of Open Access Journals (Sweden)

    K. Sriram


    Full Text Available The literature in the field of sustainable development (SD of businesses is piecemeal and diverse. This paper identifies and integrates principles that businesses could use for transformation towards SD. This is done through analogical reasoning from the source context of ecological systems to the target contexts of business socio-economic systems and machine/technology systems. The methodologies of systems thinking and morphological analysis supplement the analogical reasoning. Based on this, twelve principles for sustainable development of business are inferred for business managers and policy makers.

  7. Conjecturing via Analogical Reasoning in Developing Scientific Approach in Junior High School Students (United States)

    Supratman; Ryane, S.; Rustina, R.


    This study aims to explore the extent to which the use of analogy reasoning when students conduct conjecture in developing the scientific approach, so that the knowledge of the students can be used to build new knowledge. Analysis was conducted on student learning outcomes in Ciamis district. Based on these results, it was found the teacher not give an opportunity to the students to make conjecture on the students in problem solving as well as the construction of new knowledge. Moreover, teachers do not take advantage of analogical reasoning and scientific approach in constructing new knowledge.

  8. Analog Design for Digital Deployment of a Serious Leadership Game (United States)

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


    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.

  9. Analog VLSI implementation of resonate-and-fire neuron. (United States)

    Nakada, Kazuki; Asai, Tetsuya; Hayashi, Hatsuo


    We propose an analog integrated circuit that implements a resonate-and-fire neuron (RFN) model based on the Lotka-Volterra (LV) system. The RFN model is a spiking neuron model that has second-order membrane dynamics, and thus exhibits fast damped subthreshold oscillation, resulting in the coincidence detection, frequency preference, and post-inhibitory rebound. The RFN circuit has been derived from the LV system to mimic such dynamical behavior of the RFN model. Through circuit simulations, we demonstrate that the RFN circuit can act as a coincidence detector and a band-pass filter at circuit level even in the presence of additive white noise and background random activity. These results show that our circuit is expected to be useful for very large-scale integration (VLSI) implementation of functional spiking neural networks.

  10. Paper-based solid-phase nucleic acid hybridization assay using immobilized quantum dots as donors in fluorescence resonance energy transfer. (United States)

    Noor, M Omair; Shahmuradyan, Anna; Krull, Ulrich J


    A paper-based solid-phase assay is presented for transduction of nucleic acid hybridization using immobilized quantum dots (QDs) as donors in fluorescence resonance energy transfer (FRET). The surface of paper was modified with imidazole groups to immobilize QD-probe oligonucleotide conjugates that were assembled in solution. Green-emitting QDs (gQDs) were FRET-paired with Cy3 acceptor. Hybridization of Cy3-labeled oligonucleotide targets provided the proximity required for FRET-sensitized emission from Cy3, which served as an analytical signal. The assay exhibited rapid transduction of nucleic acid hybridization within minutes. Without any amplification steps, the limit of detection of the assay was found to be 300 fmol with the upper limit of the dynamic range at 5 pmol. The implementation of glutathione-coated QDs for the development of nucleic acid hybridization assay integrated on a paper-based platform exhibited excellent resistance to nonspecific adsorption of oligonucleotides and showed no reduction in the performance of the assay in the presence of large quantities of noncomplementary DNA. The selectivity of nucleic acid hybridization was demonstrated by single-nucleotide polymorphism (SNP) detection at a contrast ratio of 19 to 1. The reuse of paper over multiple cycles of hybridization and dehybridization was possible, with less than 20% reduction in the performance of the assay in five cycles. This work provides an important framework for the development of paper-based solid-phase QD-FRET nucleic acid hybridization assays that make use of a ratiometric approach for detection and analysis.

  11. Teaching Einsteinian physics at schools: part 1, models and analogies for relativity (United States)

    Kaur, Tejinder; Blair, David; Moschilla, John; Stannard, Warren; Zadnik, Marjan


    The Einstein-First project aims to change the paradigm of school science teaching through the introduction of modern Einsteinian concepts of space and time, gravity and quanta at an early age. These concepts are rarely taught to school students despite their central importance to modern science and technology. The key to implementing the Einstein-First curriculum is the development of appropriate models and analogies. This paper is the first part of a three-paper series. It presents the conceptual foundation of our approach, based on simple physical models and analogies, followed by a detailed description of the models and analogies used to teach concepts of general and special relativity. Two accompanying papers address the teaching of quantum physics (Part 2) and research outcomes (Part 3).

  12. Kuhn and conceptual change: on the analogy between conceptual changes in science and children (United States)

    Greiffenhagen, Christian; Sherman, Wendy


    This article argues that the analogy between conceptual changes in the history of science and conceptual changes in the development of young children is problematic. We show that the notions of ‘conceptual change’ in Kuhn and Piaget’s projects, the two thinkers whose work is most commonly drawn upon to support this analogy, are not compatible in the sense usually claimed. We contend that Kuhn’s work pertains not so much to the psychology of individual scientists, but to the way philosophers and historians should describe developments in communities of scientists. Furthermore, we argue that the analogy is based on a misunderstanding of the nature of science and the relation between science and common sense. The distinctiveness of the two notions of conceptual change has implications for science education research, since it raises serious questions about the relevance of Kuhn’s remarks for the study of pedagogical issues.

  13. Simulation of Rossi-α method with analog Monte-Carlo method

    International Nuclear Information System (INIS)

    Lu Yuzhao; Xie Qilin; Song Lingli; Liu Hangang


    The analog Monte-Carlo code for simulating Rossi-α method based on Geant4 was developed. The prompt neutron decay constant α of six metal uranium configurations in Oak Ridge National Laboratory were calculated. α was also calculated by Burst-Neutron method and the result was consistent with the result of Rossi-α method. There is the difference between results of analog Monte-Carlo simulation and experiment, and the reasons for the difference is the gaps between uranium layers. The influence of gaps decrease as the sub-criticality deepens. The relative difference between results of analog Monte-Carlo simulation and experiment changes from 19% to 0.19%. (authors)

  14. Student Analogy Reasons When Solving Area Concepts in Pyramids and Prisms (United States)

    Mashuri, A.; Sudjadi, I.; Pramudya, I.; Gembong, S.


    The purpose of this study is to describe the reasoning of students’ analogies in solving the broad concept problem in pyramids and prisms. This research method using descriptive qualitative. Data collection uses analogous reasoning tests and interviews. After that tested to 32 students of Junior High School. Based on the results of the analysis can be concluded that (1) 16% of students solve the problem of source and target problem correctly. (2) 29% of students correctly solve source problems and target problems incorrectly. (3) 55% solve source problems and target problems wrong. This is because students tend to memorize formulas not using analogy reasoning to solve new problems. Finally, the students have difficulties in solving new problems, because students are not accustomed to using the experience they have gained to solve new problems.

  15. Synthesis and Biological Evaluation of Novel 1-Alkyltryptophan Analogs as Potential Antitumor Agents

    Directory of Open Access Journals (Sweden)

    Shih-Chen Wang


    Full Text Available To seek novel antitumor agents, we designed and synthesized new 1-tryptophan analogs based on tryptophan catabolism. 1-Alkyltryptophan analogues including 1-ethyltryptophan (1-ET, 1-propyltryptophan (1-PT, 1-isopropyltryptophan (1-isoPT and 1-butyltryptophan (1-BT were synthesized from tryptophan. We examined whether those compounds had the antiproliferative effects on SGC7901 and HeLa cells line by using MTT assay in vitro, respectively. Compared to tryptophan, all targeted compounds efficiently inhibited proliferation of two cancer cell lines at 2 mmol/L for 48 hours. Among these tryptophan analogs, 1-BT showed the most powerful cytotoxicity against SGC7901 and HeLa cells at 1 mmol/L and 2 mmol/L concentration. These data suggest that some specific tryptophan analogs could be developed as potential anti-neoplastic agents.

  16. BacNet and Analog/Digital Interfaces of the Building Controls Virtual Testbed

    Energy Technology Data Exchange (ETDEWEB)

    Nouidui, Thierry Stephane [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wetter, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Li, Zhengwei [Georgia Inst. of Technology, Atlanta, GA (United States); Pang, Xiufeng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bhattacharya, Prajesh [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Haves, Philip [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)


    This paper gives an overview of recent developments in the Building Controls Virtual Test Bed (BCVTB), a framework for co-simulation and hardware-in-the-loop. First, a general overview of the BCVTB is presented. Second, we describe the BACnet interface, a link which has been implemented to couple BACnet devices to the BCVTB. We present a case study where the interface was used to couple a whole building simulation program to a building control system to assess in real-time the performance of a real building. Third, we present the ADInterfaceMCC, an analog/digital interface that allows a USB-based analog/digital converter to be linked to the BCVTB. In a case study, we show how the link was used to couple the analog/digital converter to a building simulation model for local loop control.

  17. Experiments of analog states on Lead 206 and 207

    International Nuclear Information System (INIS)

    Adam, Albert


    This research thesis aims at verifying hypotheses according to which the spread of analog states decreases as much as nuclei are far from a double magic nucleus, under some conditions. Therefore, analog states of lead 207 and 208 have been studied by proton scattering on targets in lead 206 and 207. Some theoretical aspects of analog states of isobaric spin are presented. An experimental method of determination of excitation functions is described. Results obtained for analog states in bismuth 207-208 are discussed. Results obtained on four steady lead isotopes in different laboratories are compared [fr

  18. Children's analogical reasoning in a third-grade science discussion (United States)

    May, David B.; Hammer, David; Roy, Patricia


    Expert scientific inquiry involves the generation and use of analogies. How and when students might develop this aspect of expertise has implications for understanding how and when instruction might facilitate that development. In a study of K-8 student inquiry in physical science, we are examining cases of spontaneous analogy generation. In the case we present here, a third-grader generates an analogy and modifies it to reconcile his classmates' counterarguments, allowing us to identify in these third-graders specific aspects of nascent expertise in analogy use. Promoting abilities and inclinations such as these children display requires that educators recognize and respond to them.


    National Aeronautics and Space Administration — The Bloomsburg University Goniometer (BUG) was used to make bidirectional reflectance distribution function (BRDF) measurements of Mars soil analogs at Mars...

  20. In vitro and In vivo Studies on Stilbene Analogs as Potential Treatment Agents for Colon Cancer (United States)

    Based upon the potential of resveratrol as a cancer chemopreventive agent, 27 stilbenes analogs were synthesized and tested against colon cancer cell line HT-29. Among these compounds, amino derivative (Z)-4-(3,5-dimethoxystyryl) aniline (4), (Z)-methyl 4-(3,5-dimethoxystyryl) benzoate (6) and (Z)-1...