Sample records for salicylihalamide analog saliphenylhalamide

  1. Inhibition of influenza A virus infection in vitro by saliphenylhalamide-loaded porous silicon nanoparticles. (United States)

    Bimbo, Luis M; Denisova, Oxana V; Mäkilä, Ermei; Kaasalainen, Martti; De Brabander, Jef K; Hirvonen, Jouni; Salonen, Jarno; Kakkola, Laura; Kainov, Denis; Santos, Hélder A


    Influenza A viruses (IAVs) cause recurrent epidemics in humans, with serious threat of lethal worldwide pandemics. The occurrence of antiviral-resistant virus strains and the emergence of highly pathogenic influenza viruses have triggered an urgent need to develop new anti-IAV treatments. One compound found to inhibit IAV, and other virus infections, is saliphenylhalamide (SaliPhe). SaliPhe targets host vacuolar-ATPase and inhibits acidification of endosomes, a process needed for productive virus infection. The major obstacle for the further development of SaliPhe as antiviral drug has been its poor solubility. Here, we investigated the possibility to increase SaliPhe solubility by loading the compound in thermally hydrocarbonized porous silicon (THCPSi) nanoparticles. SaliPhe-loaded nanoparticles were further investigated for the ability to inhibit influenza A infection in human retinal pigment epithelium and Madin-Darby canine kidney cells, and we show that upon release from THCPSi, SaliPhe inhibited IAV infection in vitro and reduced the amount of progeny virus in IAV-infected cells. Overall, the PSi-based nanosystem exhibited increased dissolution of the investigated anti-IAV drug SaliPhe and displayed excellent in vitro stability, low cytotoxicity, and remarkable reduction of viral load in the absence of organic solvents. This proof-of-principle study indicates that PSi nanoparticles could be used for efficient delivery of antivirals to infected cells.

  2. Prevention of wear particle-induced osteolysis by a novel V-ATPase inhibitor saliphenylhalamide through inhibition of osteoclast bone resorption.

    Directory of Open Access Journals (Sweden)

    An Qin

    Full Text Available Wear particle-induced peri-implant loosening (Aseptic prosthetic loosening is one of the most common causes of total joint arthroplasty. It is well established that extensive bone destruction (osteolysis by osteoclasts is responsible for wear particle-induced peri-implant loosening. Thus, inhibition of osteoclastic bone resorption should prevent wear particle induced osteolysis and may serve as a potential therapeutic avenue for prosthetic loosening. Here, we demonstrate for the first time that saliphenylhalamide, a new V-ATPase inhibitor attenuates wear particle-induced osteolysis in a mouse calvarial model. In vitro biochemical and morphological assays revealed that the inhibition of osteolysis is partially attributed to a disruption in osteoclast acidification and polarization, both a prerequisite for osteoclast bone resorption. Interestingly, the V-ATPase inhibitor also impaired osteoclast differentiation via the inhibition of RANKL-induced NF-κB and ERK signaling pathways. In conclusion, we showed that saliphenylhalamide affected multiple physiological processes including osteoclast differentiation, acidification and polarization, leading to inhibition of osteoclast bone resorption in vitro and wear particle-induced osteolysis in vivo. The results of the study provide proof that the new generation V-ATPase inhibitors, such as saliphenylhalamide, are potential anti-resorptive agents for treatment of peri-implant osteolysis.

  3. Analog Coding. (United States)


  4. Analog computing

    CERN Document Server

    Ulmann, Bernd


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

  5. Analog earthquakes

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  6. Analog current mode analog/digital converter (United States)

    Hadidi, Khayrollah (Inventor)


    An improved subranging or comparator circuit is provided for an analog-to-digital converter. As a subranging circuit, the circuit produces a residual signal representing the difference between an analog input signal and an analog of a digital representation. This is achieved by subdividing the digital representation into two or more parts and subtracting from the analog input signal analogs of each of the individual digital portions. In another aspect of the present invention, the subranging circuit comprises two sets of differential input pairs in which the transconductance of one differential input pair is scaled relative to the transconductance of the other differential input pair. As a consequence, the same resistor string may be used for two different digital-to-analog converters of the subranging circuit.

  7. 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.

  8. 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

  9. 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

  10. 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. <

  11. Digital to Analog Converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.; van den Boom, Jeroen M.; Dijkmans, Eise C.


    A digital to analog converter (DAC) for converting a digital signal (DS) having a maximum voltage range which corresponds to a first supply voltage (UL) into an analog signal (UOUT) having a maximum voltage range which corresponds to a second supply voltage (UH). The first supply voltage (UL) is

  12. Digital to Analog Converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.; van den Boom, Jeroen M.; Dijkmans, Eise C.


    A digital to analog converter (DAC) for converting a digital signal (DS) having a maximum voltage range which corresponds to a first supply voltage (UL) into an analog signal (UOUT) having a maximum voltage range which corresponds to a second supply voltage (UH). The first supply voltage (UL) is

  13. 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.2,3 According to Iding,4 analogies are consistent with the tenets of constructivist learning theories, which claim that learners should be actively involved and new concepts should be based on learners' previous experiences. When analogies are used during the teaching-learning process, they may promote students' understanding of abstract science concepts.5 This paper suggests a capacitor analogy that aims to foster students' conceptual understanding of capacitors in a slightly different way than Greenslade's analogy.6

  14. Meat analog: a review. (United States)

    Malav, O P; Talukder, S; Gokulakrishnan, P; Chand, S


    The health-conscious consumers are in search of nutritious and convenient food item which can be best suited in their busy life. The vegetarianism is the key for the search of such food which resembles the meat in respect of nutrition and sensory characters, but not of animal origin and contains vegetable or its modified form, this is the point when meat analog evolved out and gets shape. The consumers gets full satisfaction by consumption of meat analog due to its typical meaty texture, appearance and the flavor which are being imparted during the skilled production of meat analog. The supplement of protein in vegetarian diet through meat alike food can be fulfilled by incorporating protein-rich vegetative food grade materials in meat analog and by adopting proper technological process which can promote the proper fabrication of meat analog with acceptable meat like texture, appearance, flavor, etc. The easily available vegetables, cereals, and pulses in India have great advantages and prospects to be used in food products and it can improve the nutritional and functional characters of the food items. The various form and functional characters of food items are available world over and attracts the meat technologists and the food processors to bring some innovativeness in meat analog and its presentation and marketability so that the acceptability of meat analog can be overgrown by the consumers.

  15. 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

  16. TV Analog Station Transmitters (United States)

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

  17. Challenges in Analogical Reasoning

    CERN Document Server

    Lin, Shih-Yin


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

  18. 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.

  19. 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.

  20. Analog Frame Store Memory. (United States)


    enhancement when coupled with the video acquisition performed by the Frame Store Memory in mode 2. 3 -11 It cr (A 3 coJ 0( kLL P.- FAIRCHILO IMAGING ...AD-AOSI 979 FAIRCHILD IMAGING SYSTEMS SYOSSET N Y F/0 17/2 ANALOG FRAME STORE MEMORY . CU) JAN 80 OAAK77-C-0165 UNCLASSIFIED ED-CX-141-5 M 1 .0 H " 1...DESCRIPTION 1-2 1.1.1 Analog Frame Store Memory 1-2 1.1.2 Analog Field Storage Device 1-4 1.1.3 Image Analyzer Digital Display (IADD) 1-4 1.2 PROGRAM’S

  1. 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.

  2. 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…

  3. 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.

  4. 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.

  5. 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.

  6. How Analogy Drives Physics

    Energy Technology Data Exchange (ETDEWEB)

    Hofstadter, Doug (Indiana University)


    Many new ideas in theoretical physics come from analogies to older ideas in physics. For instance, the abstract notion of 'isospin' (or isotopic spin) originated in the prior concept of 'spin' (quantized angular momentum); likewise, the concept of 'phonon' (quantum of sound, or quantized collective excitation of a crystal) was based on the prior concept of 'photon' (quantum of light, or quantized element of the electromagnetic field). But these two examples, far from being exceptions, in fact represent the bread and butter of inventive thinking in physics. In a nutshell, intraphysics analogy-making -- borrowing by analogy with something already known in another area of physics -- is central to the progress of physics. The aim of this talk is to reveal the pervasiveness -- indeed, the indispensability -- of this kind of semi-irrational, wholly intuitive type of thinking (as opposed to more deductive mathematical inference) in the mental activity known as 'doing physics'. Speculations as to why wild analogical leaps are so crucial to the act of discovery in physics (as opposed to other disciplines) will be offered.

  7. Terrestrial Spaceflight Analogs: Antarctica (United States)

    Crucian, Brian


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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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...

  13. 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

  14. [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.

  15. Natural analog studies: Licensing perspective

    Energy Technology Data Exchange (ETDEWEB)

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


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

  16. 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...

  17. 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.

  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 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 ...

  20. Analog-to-digital converter (United States)

    Lewyn, L. L. (Inventor)


    An analog to digital converter circuit arrangement is reported that is suitable for use in ultra fast pulse height analysis. The circuit uses series connected tunnel diodes to quantize a voltage signal into discrete levels.

  1. 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 ...

  2. Analogies in Science and Science Teaching (United States)

    Brown, Simon; Salter, Susan


    Analogies are often used in science, but students may not appreciate their significance, and so the analogies can be misunderstood or discounted. For this reason, educationalists often express concern about the use of analogies in teaching. Given the important place of analogies in the discourse of science, it is necessary that students are…

  3. Components of Geometric Analogy Solution. (United States)

    Mulholland, Timothy M.; And Others


    Adults' geometric analogy solution was investigated as a function of systematic variations in the information structure of items. Latency data from verification of true and false items were recorded. A model incorporating assumptions about the form of item representation, working memory factors, and processing components and strategies was…

  4. Analog Input Data Acquisition Software (United States)

    Arens, Ellen


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

  5. A digital to analog converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.


    A digital to analog converter for a multibit digital input signal has a set of conversion elements for the positive signal excursions and a set of conversion elements for the negative signal excursions. In each set the conversion elements are selected according to a dynamic element matching

  6. A digital to analog converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.


    A digital to analog converter for a multibit digital input signal has a set of conversion elements for the positive signal excursions and a set of conversion elements for the negative signal excursions. In each set the conversion elements are selected according to a dynamic element matching

  7. 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…

  8. Designing analog circuits in CMOS

    NARCIS (Netherlands)

    Annema, Anne J.; Nauta, Bram; van Langevelde, Ronald; Tuinhout, Hans


    The evolution in CMOS technology dictated by Moore's Law is clearly beneficial for designers of digital circuits, but it presents difficult challenges, such as lowered nominal supply voltages, for their peers in the analog world who want to keep pace with this rapid progression. This article

  9. 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)

  10. 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.

  11. 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

  12. Analog Nonvolatile Computer Memory Circuits (United States)

    MacLeod, Todd


    In nonvolatile random-access memory (RAM) circuits of a proposed type, digital data would be stored in analog form in ferroelectric field-effect transistors (FFETs). This type of memory circuit would offer advantages over prior volatile and nonvolatile types: In a conventional complementary metal oxide/semiconductor static RAM, six transistors must be used to store one bit, and storage is volatile in that data are lost when power is turned off. In a conventional dynamic RAM, three transistors must be used to store one bit, and the stored bit must be refreshed every few milliseconds. In contrast, in a RAM according to the proposal, data would be retained when power was turned off, each memory cell would contain only two FFETs, and the cell could store multiple bits (the exact number of bits depending on the specific design). Conventional flash memory circuits afford nonvolatile storage, but they operate at reading and writing times of the order of thousands of conventional computer memory reading and writing times and, hence, are suitable for use only as off-line storage devices. In addition, flash memories cease to function after limited numbers of writing cycles. The proposed memory circuits would not be subject to either of these limitations. Prior developmental nonvolatile ferroelectric memories are limited to one bit per cell, whereas, as stated above, the proposed memories would not be so limited. The design of a memory circuit according to the proposal must reflect the fact that FFET storage is only partly nonvolatile, in that the signal stored in an FFET decays gradually over time. (Retention times of some advanced FFETs exceed ten years.) Instead of storing a single bit of data as either a positively or negatively saturated state in a ferroelectric device, each memory cell according to the proposal would store two values. The two FFETs in each cell would be denoted the storage FFET and the control FFET. The storage FFET would store an analog signal value

  13. 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...

  14. A digital to analog converter


    Westra, Jan R.; Annema, Anne J.


    A digital to analog converter for a multibit digital input signal has a set of conversion elements for the positive signal excursions and a set of conversion elements for the negative signal excursions. In each set the conversion elements are selected according to a dynamic element matching algorithm. To improve the mismatch-noise shaping of these algorithms, excess conversion elements may be additionally selected.

  15. 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.

  16. Third order digital-to-analog converter (United States)

    Dotson, W. P.


    System, consisting of sample and hold digital-to-analog converter, clock circuit, sample delay circuit, initial condition circuit and interpolator circuit, improves accuracy of reconstructed analog signal without increasing sample rates.

  17. 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

  18. Design and Analysis of Reconfigurable Analog System (United States)


    NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT A highly...2008/12/12/31e83bac-500f-4182- acca -4d360295fd9c.pdf, Analog Devices, Analog Dialogue 39-06, June 2005. [15] D. A. Johns, K. Martin "Analog Integrated

  19. Analogies and the 5E Model (United States)

    Orgill, Mary Kay; Thomas, Megan


    Science classes are full of abstract or challenging concepts that are easier to understand if an analogy is used to illustrate the points. Effective analogies motivate students, clarify students' thinking, help students overcome misconceptions, and give students ways to visualize abstract concepts. When they are used appropriately, analogies can…

  20. 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

  1. 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

  2. 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

  3. 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...

  4. 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.)

  5. The relationship of analogical distance to analogical function and preinventive structure: the case of engineering design. (United States)

    Christensen, Bo T; Schunn, Christian D


    Analogy was studied in real-world engineering design, using the in vivo method. Analogizing was found to occur frequently, entailing a roughly equal amount of within- and between-domain analogies. In partial support for theories of unconscious plagiarism (Brown & Murphy, 1989; Marsh, Landau, & Hicks, 1996) and Ward's (1994) path-of-least-resistance model, it was found that the reference to exemplars (in the form of prototypes) significantly reduced the number of between-domain analogies between source and target, as compared with using sketches or no external representational systems. Analogy served three functions in relation to novel design concepts: identifying problems, solving problems, and explaining concepts. Problem identifying analogies were mainly within domain, explanatory analogies were mainly between domain, and problem-solving analogies were a mixture of within- and between-domain analogies.

  6. The Young Solar Analogs Project (United States)

    Gray, Richard O.; Saken, J. M.; Corbally, C. J.; Seeds, M. F.; Morrison, S. S.


    We are carrying out a long-term project of measuring chromospheric activity and brightness variations in 31 young solar analogs (YSAs) using the Dark Sky Observatory (DSO -- Appalachian State University) 32-inch telescope and the G/M spectrograph. These YSAs are solar-type (spectral types F8 - K2) stars with ages ranging from 0.3 - 1.5 Gyr. The goal of this project is to gain better understanding of the magnetic activity of the early Sun, and especially how that activity may have impacted the development of life on the Earth. This project will also yield insights into the space environments experienced by young Earth analogs. We are currently in our 5th year of obtaining Ca II K & H chromospheric flux measurements, and are beginning to see signs of long-term activity cycles in a number of our stars. In addition, rotational modulation of the chromospheric fluxes is detectable in our data, and we have determined rotational periods for many of our stars. Short timescale increases in the K & H fluxes have been observed in a number of our stars; these events may be related to stellar flares. VATTSpec, a new moderate-resolution spectrograph on the 1.8-m Vatican Telescope in Arizona, has recently become involved with the project. This spectrograph will increase our ability to detect short-term changes in stellar activity on timescales of hours to minutes. We have been monitoring the program stars for one year in a multi-band photometric system consisting of Stromgren-v, and Johnson B, V, and R filters. We will soon add a narrow-band H-alpha filter to the system. Photometry is being carried out with a small piggy-back telescope on the 32-inch, but a robotic photometric telescope is currently being installed at DSO for this purpose. This project is supported by the National Science Foundation.

  7. 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

  8. Analog MOS integrated circuits for signal processing (United States)

    Gregorian, R.; Temes, G. C.

    Theoretical and practical aspects of analog MOS integrated circuits are discussed. The basic properties of these circuits are described, providing necessary background material in mathematics and semiconductor device physics and technology. The operation and design of such important circuits as switched-capacitor filters, analog-to-digital and digital-to-analog converters, amplifiers, modulators, and oscillators. Practical problems encountered in design are discussed, solutions are provided, and some examples of actual system applications are given.

  9. 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.

  10. Analogies in biology textbooks in zoology teaching

    Directory of Open Access Journals (Sweden)

    Saulo Cézar Seiffert Santos


    Full Text Available The biologic structures of living creatures are of difficult understanding for students, because they are usually unknown by those, in needs of strategic didactics in order to facilitate the student understanding. There are several strategies and methods for teaching, such as, analogies, metaphors, descriptions, among others. In this article we aim to identify, assess and classify the analogies used in the Higher School Biology textbooks, commonly used in Public State Schools of Manaus – AM, related to the zoology theme. The methodological procedure includes: a analysis of the whole zoological content of the most used textbooks in the public state network of Amazonas throughout the year; b three didactic textbooks have been specifically analyzed in order to specify the class taxon of “Fish” for the comparison of possible variations of types and quantities of analogies. The adopted classification of analogies was of Curtis & Reigeluth (1984 and the model of enriching analysis was according to the TWA Glynn model (Harrison & Treagust, 1993. It has been concluded that the use of analogies is greater in the content of invertebrates than that of vertebrates. Most Analogies are presented in a simple and direct manner, comparing structures, concrete to concrete, and of verbal mediation, almost nothing is presented in a diverse and heuristic manner of Zoology content on the LD. The development of limits of comparison and reflexion about the analogies was rare, only the presentation of the analogue and the target of analogy occurred.

  11. The Use of Analogies in Written Text. (United States)

    Curtis, Ruth V.; Reigeluth, Charles M.


    Describes a study that explored and inductively classified analogies in 26 science textbooks, ranging from elementary to postsecondary level, to provide a systematic description of the phenomenon and generate prescriptive principles for their use in instruction. Classification categories include analogical relationship, presentation format,…

  12. The Pennies-as-Electrons Analogy (United States)

    Ashmann, Scott


    Everyday experiences familiarize students with the ways in which electricity is used, but often the underlying concepts remain a mystery. Teachers often use analogies to help students relate the flow of electrons to other common systems, but many times these analogies are incomplete and lead to more student misconceptions. However, the "pass the…

  13. 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.

  14. 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…

  15. A Mechanical Analogy for the Photoelectric Effect (United States)

    Kovacevic, Milan S.; Djordjevich, Alexandar


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

  16. 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…


    African Journals Online (AJOL)


    Nov 27, 2008 ... can still establish scientifically that dinosaurs once existed, since their fossils remain. However, this is in spite of the principle of analogy and we may likewise be able to establish miracles historically if we have credible testimony that remains. The principle of analogy also appears to assume metaphysical.


    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.

  19. 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...

  20. 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

  1. 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.

  2. Analogies: Explanatory Tools in Web-Based Science Instruction (United States)

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


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

  3. Programmable Analog-To-Digital Converter (United States)

    Kist, Edward H., Jr.


    High-speed analog-to-digital converter with programmable voltage steps that can be changed during operation. Allows concentration of converter resolution over specific portion of waveform. Particularly useful in digitizing wind-shear radar and lidar return signals, in digital oscilloscopes, and other applications in which desirable to increase digital resolution over specific area of waveform while accepting lower resolution over rest of waveform. Effective increase in dynamic range achieved without increase in number of analog-to-digital converter bits. Enabling faster analog-to-digital conversion.

  4. Identifying Solar Analogs in the Kepler Field (United States)

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


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

  5. Photonic Analog-to-Digital Conversion Technology

    National Research Council Canada - National Science Library

    Ng, W; Lu, L; Yap, D; Bridges, W; Mokhtari, M


    This report documents the work undertaken by HRL Laboratories, LLC and its subcontractors, California Institute of Technology and Raytheon Electronics Systems, on the development of multi-GHz photonic analog-to-digital (A/D...


    Rodgers, G.W.; Althouse, J.E.; Anderson, D.P.; Bussey, G.R.; Minnear, L.H.


    Electrical apparatus is described, particularly useful in telemetry work, for converting analog signals into electrical pulses and recording them. An electronic editor commands the taking of signal readings at a frequency which varies according to linearity of the analog signal being converted. Readings of information signals are recorded, along with time base readings and serial numbering, if desired, on magnetic tape and the latter may be used to operate a computer or the like. Magnetic tape data may be transferred to punched cards.

  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. 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. 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.

  10. Digital Analog Design: A Highly-Efficient Method to Design Analog Circuits (United States)


    Digital Analog Design: A Highly-Efficient Method to Design Analog Circuits* Mark Horowitz and Byong Lim Department of Electrical Engineering...Stanford University Stanford, CA, 940305 Abstract: The past 30 years have seen an enormous growth in the power and sophistication of digital tools, while progress in analog tools has been much more modest. Digital tools use many abstractions to allow them to validate

  11. Analog Signal Correlating Using an Analog-Based Signal Conditioning Front End (United States)

    Prokop, Norman; Krasowski, Michael


    This innovation is capable of correlating two analog signals by using an analog-based signal conditioning front end to hard-limit the analog signals through adaptive thresholding into a binary bit stream, then performing the correlation using a Hamming "similarity" calculator function embedded in a one-bit digital correlator (OBDC). By converting the analog signal into a bit stream, the calculation of the correlation function is simplified, and less hardware resources are needed. This binary representation allows the hardware to move from a DSP where instructions are performed serially, into digital logic where calculations can be performed in parallel, greatly speeding up calculations.

  12. 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

  13. 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.

  14. 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.

  15. 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…

  16. The Effect of Analogy-Based Teaching on Students' Achievement and Students' Views about Analogies (United States)

    Genc, Murat


    The purpose of this study is to determine the effect of the analogy-based teaching on students' achievement and students' views about analogies. In this research, Solomon group design which is one of the experimental designs, was implemented. The sample of the research consists of 108 students in four 6th grade classes in Turkey. The achievement…

  17. Xampling: Compressed Sensing of Analog Signals

    CERN Document Server

    Mishali, Moshe


    Xampling generalizes compressed sensing (CS) to reduced-rate sampling of analog signals. A unified framework is introduced for low rate sampling and processing of signals lying in a union of subspaces. Xampling consists of two main blocks: Analog compression that narrows down the input bandwidth prior to sampling with commercial devices followed by a nonlinear algorithm that detects the input subspace prior to conventional signal processing. A variety of analog CS applications are reviewed within the unified Xampling framework including a general filter-bank scheme for sparse shift-invariant spaces, periodic nonuniform sampling and modulated wideband conversion for multiband communications with unknown carrier frequencies, acquisition techniques for finite rate of innovation signals with applications to medical and radar imaging, and random demodulation of sparse harmonic tones. A hardware-oriented viewpoint is advocated throughout, addressing practical constraints and exemplifying hardware realizations where...

  18. Formal analogies in physics teacher education

    DEFF Research Database (Denmark)

    Avelar Sotomaior Karam, Ricardo; Ricardo, Elio


    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...... 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...

  19. 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...

  20. Landauer Bound for Analog Computing Systems

    CERN Document Server

    Diamantini, M. Cristina; Trugenberger, Carlo A.


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

  1. 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.

  2. Analogy Mapping Development for Learning Programming (United States)

    Sukamto, R. A.; Prabawa, H. W.; Kurniawati, S.


    Programming skill is an important skill for computer science students, whereas nowadays, there many computer science students are lack of skills and information technology knowledges in Indonesia. This is contrary with the implementation of the ASEAN Economic Community (AEC) since the end of 2015 which is the qualified worker needed. This study provided an effort for nailing programming skills by mapping program code to visual analogies as learning media. The developed media was based on state machine and compiler principle and was implemented in C programming language. The state of every basic condition in programming were successful determined as analogy visualization.


    Directory of Open Access Journals (Sweden)


    Full Text Available In this paper the possibility of using hydraulic analog simulation in the study of problems of unsteady gas dynamics is considered. The analysis of differential equations of unsteady motion of bodies in supersonic flow using the theory of similarity and dimensional analysis. Obtained similarity criteria that must be identical for both the real gas flow and the modeling of fluid flow. Using a hydraulic analog modeling for research in non-stationary gas dynamics provides valuable information necessary for understanding the physics of the processes and the construction of more sophisticated mathematical models.

  4. 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.

  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. Pseudolog Digital-to-Analog Converter (United States)

    Gooder, S. T.


    Sensitivity decreases by 10 at beginning of each input decade. Method conceived to convert binary-coded data to suitable linear form for stripchart recording. Strip-chart recordings obtained from typical pressure readings in a vacuum system during pumpdown. In reading curve, BCD digital vacuum-gage output processed by analog-to-digital converter in such way that only reading digits (but not range) appear in output. In range and reading, range also converted to analog and placed as most significant digit.

  7. A quadratic analog-to-digital converter (United States)

    Harrison, D. C.; Staples, M. H.


    An analog-to-digital converter with a square root transfer function has been developed for use with a pair of CCD imaging detectors in the White Light Coronagraph/X-ray XUV Telescope experiment to be flown as part of the Internal Solar Polar Mission. It is shown that in background-noise-limited instrumentation systems a quadratic analog-to-digital converter will allow a maximum dynamic range with a fixed number of data bits. Low power dissipation, moderately fast conversion time, and reliability are achieved in the proposed design using standard components and avoiding nonlinear elements.

  8. Transparent Analogs for Alloy Phase Studies (United States)

    Frazier, D. O.; Smith, James E., Jr.


    Report describes experiments to add information to data base supporting use of transparent, partially miscible liquids and solids as analogs in studies of alloy solidification. Behavior of these materials observed directly while they undergo liquid/liquid and liquid/solid phase transformations. Light-scattering techniques used to determine phase boundaries. Transparent analogs allow observation of both solidification patterns and processes leading to those patterns, whereas metal alloys require tedious post-solidification metallographic analyses because processes not generally observed. Experiments with transparent substances safer and cheaper since conducted at much lower temperatures.

  9. Analog graphic display method and apparatus (United States)

    Kronberg, J.W.


    Disclosed are an apparatus and method for using an output device such as an LED to show the approximate analog level of a variable electrical signal wherein a modulating AC waveform is superimposed either on the signal or a reference voltage, both of which are then fed to a comparator which drives the output device. Said device flashes at a constant perceptible rate with a duty cycle which varies in response to variations in the level of the input signal. The human eye perceives these variations in duty cycle as analogous to variations in the level of the input signal. 21 figures.

  10. 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

  11. 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

  12. Radiation Behavior of Analog Neural Network Chip (United States)

    Langenbacher, H.; Zee, F.; Daud, T.; Thakoor, A.


    A neural network experiment conducted for the Space Technology Research Vehicle (STRV-1) 1-b launched in June 1994. Identical sets of analog feed-forward neural network chips was used to study and compare the effects of space and ground radiation on the chips. Three failure mechanisms are noted.

  13. Atwood and Poggendorff: an insightful analogy

    DEFF Research Database (Denmark)

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


    - 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....

  14. 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,

  15. Analog voicing detector responds to pitch (United States)

    Abel, R. S.; Watkins, H. E.


    Modified electronic voice encoder /Vocoder/ includes an independent analog mode of operation in addition to the conventional digital mode. The Vocoder is a bandwidth compression equipment that permits voice transmission over channels, having only a fraction of the bandwidth required for conventional telephone-quality speech transmission.

  16. 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.

  17. 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...

  18. 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…

  19. Invention through Form and Function Analogy (United States)

    Rule, Audrey C.


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

  20. SSERVI Analog Regolith Simulant Testbed Facility (United States)

    Minafra, J.; Schmidt, G. K.


    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. The SSERVI Analog Regolith Simulant Testbed 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. SSERVI provides a bridge between several groups, joining together researchers from: 1) scientific and exploration communities, 2) multiple disciplines across a wide range of planetary sciences, and 3) domestic and international communities and partnerships. This testbed provides a means of consolidating the tasks of acquisition, storage and safety mitigation in handling large quantities of regolith simulant Facility hardware and environment testing scenarios include, but are not limited to the following; 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, and Surface features (i.e. grades and rocks) Numerous benefits vary from easy access to a controlled analog regolith simulant testbed, and planetary exploration activities at NASA Research Park, to academia and expanded commercial opportunities in California's Silicon Valley, as well as public outreach and education opportunities.

  1. RF digital-to-analog converter (United States)

    Conway, P.H.; Yu, D.U.L.


    A digital-to-analog converter is disclosed for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration. 18 figs.

  2. 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…

  3. 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.

  4. Optical folding-flash analog-to-digital converter with analog encoding. (United States)

    Jalali, B; Xie, Y M


    We describe an optically assisted folding-flash analog-to-digital converter. The periodic transfer function of the Mach-Zehnder interferometer is used to perform analog folding on the electronic signal to be quantized. A novel analog encoding scheme for efficient generation of gray code digital data is proposed. The new encoding scheme eliminates the requirement for interferometers with ultralow V(pi), which, so far, has hindered the development of such systems. The encoding concept is experimentally demonstrated through the use of LiNbO(3) modulators.

  5. Radioiodinated fatty acid analogs for myocardial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ruyan, M.K.


    Fatty acids are the preferred substrate for the normoxic heart. About sixty percent of the energy required by the myocardium is provided by fatty acid [beta]-oxidation. Many scientists have focused on the alterations in fatty acid metabolism in the ischemic heart for the development of radiolabelled fatty acids for functional imaging of the heart. Three main categories of compounds were synthesized: tetrazoles (1 and 2), glycidic and [alpha]-methylene acids (3-5), and analogs of oleic acid (6,7 and 7A). The tetrazole group has a similar pKa and size to that of a carboxyl group; however, such fatty acid analogs cannot undergo normal fatty acid metabolism. Glycidic and [alpha]-methylene analogs are potential irreversible inhibitors of fatty acid metabolism. Oleic acid analogs were investigated to assess the affect of stereochemical consequences on biodistribution. The key intermediates in the synthesis of the target compounds were [omega]-nitrophenyl alkylcarboxylic acids and alcohols, which were made using a variety of cross-coupling reactions. The Wittig reaction, which was used in the synthesis of tetrazole 1 and glycidic acid 3, gave low yields of the cross-coupled products. The remaining target compounds were synthesized by condensation of appropriate RCu (CN) ZnI and substituted benzyl bromides or by Pd[sup II] catalyzed cross-coupling of substituted arylhalides with suitable alkynes. The latter two reactions produced much higher yields of the desired products. All of the target compounds were radiolabeled with [sup 125]I by various Cu(I) catalyzed radioiodine exchange procedures and were then subjected to tissue biodistribution (TD) studies in rats. Except for the 15-(4-iodophenyl)-2-methylene-pentadecanoic acid (5), all of the fatty acid analogs failed to surpass clinically-used 15-(4-iodophenyl)pentadecanoic acid (IPPA) in their ability to be taken up and retained by the rat myocardium.

  6. What makes an analogy difficult? The effects of order and causal structure on analogical mapping. (United States)

    Keane, M T


    In 4 experiments, the author tested 2 factors that affect the difficulty of analogies: order of presentation of information and causal structure. Experiments 1, 2, and 4 showed robust order effects for the positioning of sentences-sentence pairs in a variety of mapping problems. Experiments 2, 3, and 4 revealed the effects of causal structure in these analogies. Experiment 3 showed that the beneficial effects of causal structure are most marked in thematic, mapping problems presented in a casual question-answering context. Experiment 4 dealt with the interaction between order and causal structure and showed that order effects occur only in the presence of causal structure. Of all the analogy models in the literature, the incremental analogy machine is the best predictor of these results.

  7. 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.

  8. 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).

  9. 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.

  10. High-speed analog CMOS pipeline system (United States)

    Möschen, J.; Caldwell, A.; Hervas, L.; Hosticka, B.; Kötz, U.; Sippach, B.


    We present a switched-capacitor readout system for high speed analog signals. It consists of a 10 MHz four-channel delay-line chip with 58 samples per channel and a 12 channel buffer chip with a sampling rate of 1 MHz and a depth of nine samples. In addition the buffer chip includes an analog multiplexer with 25 inputs for the buffer channels and for 13 additional unbuffered signals. Both chips have been fabricated in CMOS-technology and will be used for the readout of the ZEUS high resolution calorimeter. The circuit and chip concept will be presented and some design optimizations will be discussed. Measurements from integrated prototypes will be given including some experimental data from irradiated chips.

  11. Playing with a double-edged sword: Analogies in biochemistry (United States)

    Orgill, Marykay

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

  12. N-Zero Integrated Analog Classifier (NINA) (United States)


    detected signals. For physical- asset detection and classification, passive piezoelectric MEMS resonant seismic sensors will be utilized to produce...computational circuits operating deep in the weak inversion regime and non-volatile analog memories to classify seismic signals at extremely low...frequencies to maximize the sensor output voltage with generator signal. Figure 3. Vibration signal spectrum measured from by a sensor located atop the

  13. 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

  14. Analog Processor To Solve Optimization Problems (United States)

    Duong, Tuan A.; Eberhardt, Silvio P.; Thakoor, Anil P.


    Proposed analog processor solves "traveling-salesman" problem, considered paradigm of global-optimization problems involving routing or allocation of resources. Includes electronic neural network and auxiliary circuitry based partly on concepts described in "Neural-Network Processor Would Allocate Resources" (NPO-17781) and "Neural Network Solves 'Traveling-Salesman' Problem" (NPO-17807). Processor based on highly parallel computing solves problem in significantly less time.

  15. 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.

  16. 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.

  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...... anticancer potency, but similar toxicity causing hypercalcemia. We focused on the effect of these compounds on the stimulation of expression of human cathelicidin antimicrobial peptide (CAMP) whose gene has a vitamin D response element in its promoter. Expression of CAMP mRNA and protein increased in a dose...

  18. Sensing Methods for Detecting Analog Television Signals (United States)

    Rahman, Mohammad Azizur; Song, Chunyi; Harada, Hiroshi

    This paper introduces a unified method of spectrum sensing for all existing analog television (TV) signals including NTSC, PAL and SECAM. We propose a correlation based method (CBM) with a single reference signal for sensing any analog TV signals. In addition we also propose an improved energy detection method. The CBM approach has been implemented in a hardware prototype specially designed for participating in Singapore TV white space (WS) test trial conducted by Infocomm Development Authority (IDA) of the Singapore government. Analytical and simulation results of the CBM method will be presented in the paper, as well as hardware testing results for sensing various analog TV signals. Both AWGN and fading channels will be considered. It is shown that the theoretical results closely match with those from simulations. Sensing performance of the hardware prototype will also be presented in fading environment by using a fading simulator. We present performance of the proposed techniques in terms of probability of false alarm, probability of detection, sensing time etc. We also present a comparative study of the various techniques.

  19. 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

  20. Kukoamine A analogs with lipoxygenase inhibitory activity. (United States)

    Hadjipavlou-Litina, Dimitra; Garnelis, Thomas; Athanassopoulos, Constantinos M; Papaioannou, Dionissios


    Kukoamine A (KukA) is a spermine (SPM) conjugate with dihydrocaffeic acid (DHCA), with interesting biological activities. The four possible regioisomers of KukA, as well as a series of KukA analogs incorporating changes in either the SPM or the DHCA structural units, were evaluated for their antioxidant activity and their inhibitory activity on soybean lipoxygenase (LOX) and lipid peroxidation. The reducing properties of the compounds were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay and found to be in the range 5-97.5%. KukA significantly inhibits LOX with IC(50) 9.5 microM. All tested analogs inhibited lipid peroxidation in the range of 11-100%. The most potent compounds KukA and its analog 3, in which the DHCA units had been replaced by O,O9-dimethylcaffeic acid units, were studied for their anti-inflammatory activity in vivo on rat paw edema induced by carrageenan and found to be of comparable activity to indomethacin. The results of the biological tests are discussed in terms of structural characteristics.

  1. Nonlinear feedback reduces analog-to-digital converter error (United States)

    Munoz, R. M.


    Nonlinear analog-to-digital converter measures the analog input level and continuously adjusts the digital readout scale sensitivity to effectively increase the accuracy. It is able to acquire more accurate low-level data.

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


    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 doe...

  3. 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…

  4. Administration of Biosimilar Insulin Analogs: Role of Devices. (United States)

    Heinemann, Lutz; Fritz, Ingo; Khatami, Hootan; Edelman, Steven V


    With the expiration of patent protection for several originator insulin analog molecules, the availability of insulin analog copies is set to increase. Many regulatory authorities have developed, and continue to refine, guidelines for the approval of biosimilar insulin analogs. Aspects such as the structure, pharmacokinetics and pharmacodynamics, efficacy, safety, and immunogenicity of biosimilar insulin analogs are extensively addressed in these guidelines, but how the biosimilar insulin analog is administered to people with diabetes is not usually a topic. The aim of this article is to highlight that the delivery device-drug combination is of particular importance. Regulatory, legal, and practical aspects of the delivery device, be it a syringe, pen, or pump, have to be considered in the context of biosimilar insulin analogs. Although the safety and efficacy of biosimilar insulin analogs per se are of primary importance for physicians and people with diabetes, functions and features of the devices used for administration also require attention from a practical point of view. Unfortunately, although there are several clinical studies investigating the technical aspects of and patient preference for the originator insulin analog pens, there are currently very little published data for nonoriginator or biosimilar insulin analog pens. In addition, it is not known if it is safe to assume that a biosimilar insulin analog cartridge is compatible with an existing originator insulin analog pen. We believe that there is a need for more discussion on the role of devices for administration of biosimilar insulin analogs.

  5. Anti-inflammatory effect of thalidomide dithiocarbamate and dithioate analogs. (United States)

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


    Thalidomide has anti-inflammatory, immunomodulatory, and anti-angiogenic properties. It has been used to treat a variety of cancers and autoimmune diseases. This study aimed to characterize anti-inflammatory activities of novel thalidomide analogs by exploring their effects on splenocytes proliferation and macrophage functions and their antioxidant activity. MTT assay was used to assess the cytotoxic effect of thalidomide analogs against splenocytes. Tumor necrosis factor (TNF-α) and nuclear factor kappa B (NF-κB-P65) were determined by enzyme-linked immunosorbent assay (ELISA). Nitric oxide (NO) was estimated by colorimetric assay. Antioxidant activity was examined by ORAC assay. Our results demonstrated that thalidomide dithioate analog 2 and thalidomide dithiocarbamate analog 4 produced a slight increase in splenocyte proliferation compared with thalidomide. Thalidomide dithiocarbamate analog 1 is a potent inhibitor of TNF-α production, whereas thalidomide dithiocarbamate analog 5 is a potent inhibitor of both TNF-α and NO. Analog 2 has a pronounced inhibitory effect on NF-κB-P65 production level. All thalidomide analogs showed prooxidant activity against hydroxyl (OH) radical. Analog 1 and thalidomide dithioate analog 3 have prooxidant activity against peroxyl (ROO) radical in relation to thalidomide. On the other hand, analog 4 has a potent scavenging capacity against peroxyl (ROO) radical compared with thalidomide. Taken together, the results of this study suggest that thalidomide analogs might have valuable anti-inflammatory activities with more pronounced effect than thalidomide itself. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. 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

  7. 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

  8. 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…

  9. An optimized analog to digital converter for WLAN analog front end (United States)

    Mao, Ye; Yumei, Zhou; Bin, Wu; Jianhua, Jiang


    A 10 bit 80 MSPS analog to digital converter optimized for WLAN analog front end is presented. In contrast to conventional 1.5 bit pipeline architecture, four optimized multi-bit multiply digital to analog converter stages are implemented. An on-chip low-noise reference buffer is proposed for SoC integration purposes, and a wide-bandwidth wide swing sample and hold amplifier is also presented for achieving a good dynamic range. The converter was fabricated in 0.18 μm 1P6M CMOS technology, and the core area occupies approximately 0.85 mm2. Measured results show that with an 11 MHz input signal, it provides a 9.4 bit effective number of bits and a 72 dBc spurious frequency dynamic range when sampled at 80 MHz.

  10. 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

  11. Digital to Analog Converter Dac 0800 with Pc-based


    Dedy Erwan Kustianto; Ir. Irawan Nimara, MM


    Computer produces a digital signal output of logic "0" and "1". While electronicdevices typically use an analog signal as a voltage source that a certain amount.Electronic devices that require analog signals can be connected to a computer using adigital to analog converter circuit. Digital to analog converter is used to change thedigital signal into analogue signal.To be able to relate to the computer to analog converter circuit, an interface is needed.The interface is often used in design is...

  12. Analog superconducting quantum simulator for Holstein polarons (United States)

    Mei, Feng; Stojanović, Vladimir M.; Siddiqi, Irfan; Tian, Lin


    We propose an analog quantum simulator for the Holstein molecular-crystal model based on a superconducting circuit QED system in the dispersive regime. By varying the driving field on the superconducting resonators, one can access both the adiabatic and antiadiabatic regimes of this model, and the strong electron-phonon coupling required for small-polaron formation can be readily reached. We show that a small-polaron state of arbitrary quasimomentum can be generated by applying a microwave pulse to the resonators. We also show that significant squeezing in the resonator modes can be achieved in the polaron-crossover regime through a measurement-based scheme.

  13. Digital and analogical reality in proteomics investigation. (United States)

    Urbani, Andrea; Castagnola, Massimo; Fasano, Mauro; Bini, Luca; Modesti, Alessandra; Timperio, Anna Maria; Roncada, Paola


    Are protein functions continuous or discretized? Proteomics investigations are starting to address this non-trivial awesome question focusing upon determining the nature of biological molecular relationships. In the following editorial we present a number of experimental studies published in this themed Proteomics Issue demonstrating the development of a new analogical vision for the interpretation of genotype-phenotype relationships. New metrics and languages are evolving, which may complement the insufficiency based on a binary digital interpretation of biological phenomena, providing new tools for the interpretation of large scale-experimental studies.

  14. 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.

  15. 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.

  16. Analog IC reliability in nanometer CMOS

    CERN Document Server

    Maricau, Elie


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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Photonically assisted analog-to-digital conversion (United States)

    Asuri, Bhushan Shanti

    The evolutionary progress in electronic Analog to Digital Converters is not sufficient to meet the needs of high- speed, digital, radar receivers. We present a wide variety of techniques to address the problem of ultra- fast A/D conversion using photonics. We propose architectures, which map an electrical signal into the optical wavelength domain. The wavelength-mapped signal can then be manipulated using dispersive optic devices. The basic architectures based on time-wavelength mapping are Time Stretch, Wavelength Division Sampling and Wavelength Sampling and Shuffle. TS and WSS allow us to process segments of the electrical signal. This segment- interleaving is a potential novel strength of photonic analog-to-digital conversion techniques. The important experimental achievements include demonstration of 130 Gsa/s 7ENOB TSADC, with filtering over 1 GHZ and 30 Gsa/s, 4ENOB TSADC system over 4GHz. In the case of WDS systems we have shown 12 Gsa/s continuous time WDS system and 100 Gsa/s WDS system. We have also performed preliminary experiments to show the viability of a 16 Gsa/s, 4 channel WSS system with time aperture of 500ns. The important analytical milestones include a link level analysis of dynamic range of TSADC. We have also analyzed the effect of fiber dispersion (β2 and β3) on TSADC and the effect of mismatch in sample interleaved systems.

  2. Amygdalin analogs for the treatment of psoriasis. (United States)

    Perez, Juan J


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

  3. Metaphor and analogy in everyday problem solving. (United States)

    Keefer, Lucas A; Landau, Mark J


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

  4. A Systematic Evaluation of Analogs and Automated Read ... (United States)

    Read-across is a data gap filling technique widely used within category and analog approaches to predict a biological property for a data-poor (target) chemical using known information from similar (source analog) chemical(s). Potential source analogs are typically identified based on structural similarity. Although much guidance has been published for read-across, practical principles for the identification and evaluation of the scientific validity of source analogs remains lacking. This case study explores how well 3 structure descriptor sets (Pubchem, Chemotyper and MoSS) are able to identify analogs for read-across and predict Estrogen Receptor (ER) binding activity for a specific class of chemicals: hindered phenols. For each target chemical, analogs were selected using each descriptor set with two cut-offs: (1) Minimum Tanimoto similarity (range 0.1 - 0.9), and (2) Closest N analogs (range 1 - 10). Each target-analog pair was then evaluated for its agreement with measured ER binding and agonism. The analogs were subsequently filtered using: (1) physchem properties (LogKow & Molecular Volume), and (2) number of literature sources as a marker for the quality of the experimental data. A majority vote prediction was made for each target phenol by reading-across from the closest N analogs. The data set comprised 462 hindered phenols and 257 non-hindered phenols. The results demonstrate that: (1) The concordance in ER activity rises with increasing similarity,

  5. A Systematic Evaluation of Analogs for the Read-across ... (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 based on structural similarity. Although much guidance has been published for read-across, practical guiding principles for the identification and evaluation of the scientific validity of source analogs, which is a critical step in deriving a robust read-across prediction, remains largely lacking.This case study explores the extent to which 3 structure descriptor sets (Pubchem, Chemotyper and MoSS) and their combinations are able to identify valid analogs for reading across Estrogen Receptor (ER) activity for a specific class of chemicals: hindered phenols. For each target chemical, two sets of analogs (hindered and non-hindered phenols) were selected using each descriptor set with two cut-offs: (1). Minimum Tanimoto similarity (range 0.1 - 0.9), and (2). Closest N analogs (range 1 - 10). Each target-analog pair was then evaluated for its agreement with measured ER binding and agonism. Subsequently, the analogs were filtered using physchem properties (LogKow & Molecular Volume) and the resultant agreement between each target-analog pair was evaluated. The data set comprised 462 hindered phenols and 296 non-hindered phenols. The results demonstrate that: (1). The concordance in ER activity r

  6. 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...

  7. 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.

  8. 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.

  9. Noise in time-discrete analog filters (United States)

    Kroemer, B.; Mueller, R.; Stegherr, M.; Klar, H.; Ulbrich, W.

    The most important noise sources in time-discrete analog filters which can be monolithically integrated as CCD and switched-capacitor structures are described. In CCD filters, these sources are thermal kTC noise of the input and output levels and unloading processes at the surface attraction sites. Attainable signal-to-noise ratios and optimization possibilities are stated. For SC filters, the most important noise sources are kTC noise and l/f noise. On-chip clock jitter noise can be suppressed by differential processing. The present measurements on integrated MOS switching transistors with small areas confirm the thermal kTC noise limit and show that there is no additional l/f contribution to the noise from the switches. For the integrator, good agreement is obtained between theory and experiment when an operational amplifier with finite unity-gain frequency is included.

  10. 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.

  11. Principles of digital and analog communications

    CERN Document Server

    Gibson, Jerry D


    This textbook for the first course in communications covers analog and digital systems and emphasizes digital communications. It covers data transmission, signal space, optimal receivers, and pulse code modulation, and includes readable treatments of coded modulation and continuous phase modulation. Advanced mathematics is kept to a minimum-Fourier series, Fourier transforms, linear systems, random variables, and stochastic process are described thoroughly. It includes data compression of speech and images and a full chapter coverage of information theory, rate distortion theory and coded modulation. It relates digital communications theory to current practice and covers digital communications over band-width constrained channels, including pulse shaping and equilization. -- Dieser Text bezieht sich auf eine vergriffene oder nicht verfügbare Ausgabe dieses Titels.

  12. Analog noise reduction in enzymatic logic gates. (United States)

    Melnikov, Dmitriy; Strack, Guinevere; Pita, Marcos; Privman, Vladimir; Katz, Evgeny


    In this work, we demonstrate both experimentally and theoretically that the analog noise generation by a single enzymatic logic gate can be dramatically reduced to yield gate operation with virtually no input noise amplification. We demonstrate that when a cosubstrate with a much smaller affinity than the primary substrate is used, a negligible increase in the noise output from the logic gate is obtained, as compared to the input noise level. Our general theoretical conclusions were confirmed by experimental realizations of the AND logic gate based on the enzyme horseradish peroxidase using hydrogen peroxide as the substrate, with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) or ferrocyanide as cosubstrates with vastly different rate constants.

  13. 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...

  14. Analogical transfer in the THOG task. (United States)

    Koenig, Cynthia S; Griggs, Richard A


    The influences of surface and structural similarity on analogical transfer were examined with 318 undergraduate participants in four experiments using Needham and Amado's (1995) Pythagoras THOG problem as the source problem and Wason's standard abstract THOG task as the target problem. In Experiments 1-3, systematic changes in surface similarity between the source and target problems were introduced by changing the named exemplar, the dimensional values, and the dimensions, respectively, in the target problem. Significant transfer was obtained in all three experiments. In Experiment 4, we explored the basis of this transfer by examining three versions of the Pythagoras THOG problem, factorially combining its facilitating features as source problems. Results indicated that the inclusion of a hypothesis generation request was necessary for significant transfer. The implications of our findings for using transfer versus facilitation as the performance criterion for deductive reasoning are considered.

  15. Analogy between fluid cavitation and fracture mechanics (United States)

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


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

  16. Synthesis and Evaluation of Desmethyl Azumamide Analogs

    DEFF Research Database (Denmark)

    Maolanon, Alex

    associated with various types of cancer and HDACs have therefore been a target in the development of anticancer drugs. So far, two HDAC inhibitors have been approved by the food and drug administration (FDA) and several compounds are in clinical trials. Macrocyclic HDAC inhibitors are interesting compounds...... interactions with the large cap group. The natural compounds have been used as an inspiration to synthesize new HDAC inhibitors. A small structure activity relationship (SAR) study was conducted in collaboration with Jesper S. Villadsen. Aromatic substituents in the cyclic peptide were explored, while...... and Peter Fristrup. Compared to the natural compounds, the 3Dstructure of the scaffold in the azumamide analogs were similar. Although a conclusion was not found, the preliminary docking results indicated favorable lipophilic interaction with the methyl group in the azumamides. Largazole is another...

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

    Evanchuk, Vincent L. (Inventor)


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

  18. [Reasoning by analogy in chemical history: fallacies and guidelines]. (United States)

    Snelders, H A


    In chemistry (and natural science in general) reasoning in terms of analogy may be of great practical value as well as of theoretical significance. At the same, however, the use of analogy is risky and the results are uncertain. In alchemy and iatrochemistry analogies between the living and the non-living nature have been carried too far. At the end of the 19th century an analogy was drawn between chemical phenomena and the Darwinian theory of evolution. Another example of an overexaggerated analogy can be found in Lavoisier's theory of acids, where oxygen was considered to be the general principle of acidity. Reasoning by analogy is mostly based on an inner conviction. It leads to provisional predictions in such cases where the required facts are not, or incompletely, at our disposal.

  19. 23rd workshop on Advances in Analog Circuit Design

    CERN Document Server

    Baschirotto, Andrea; Makinwa, Kofi


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

  20. Bridging analog and digital video in the surgical setting. (United States)

    Miron, Hagai; Blumenthal, Eytan Z


    Editing surgical videos requires a basic understanding of key technical issues, especially when transforming from analog to digital media. These issues include an understanding of compression-decompression (eg, MPEGs), generation quality loss, video formats, and compression ratios. We introduce basic terminology and concepts related to analog and digital video, emphasizing the process of converting analog video to digital files. The choice of hardware, software, and formats is discussed, including advantages and drawbacks. Last, we provide an inexpensive hardware-software solution.

  1. 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.

  2. 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

  3. CRC handbook of neurohypophyseal hormone analogs. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

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


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

  4. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  6. 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.

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

    CERN Document Server

    Ohnhäuser, Frank


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

  8. Is the link from working memory to analogy causal? No analogy improvements following working memory training gains. (United States)

    Richey, J Elizabeth; Phillips, Jeffrey S; Schunn, Christian D; Schneider, Walter


    Analogical reasoning has been hypothesized to critically depend upon working memory through correlational data, but less work has tested this relationship through experimental manipulation. An opportunity for examining the connection between working memory and analogical reasoning has emerged from the growing, although somewhat controversial, body of literature suggests complex working memory training can sometimes lead to working memory improvements that transfer to novel working memory tasks. This study investigated whether working memory improvements, if replicated, would increase analogical reasoning ability. We assessed participants' performance on verbal and visual analogy tasks after a complex working memory training program incorporating verbal and spatial tasks. Participants' improvements on the working memory training tasks transferred to other short-term and working memory tasks, supporting the possibility of broad effects of working memory training. However, we found no effects on analogical reasoning. We propose several possible explanations for the lack of an impact of working memory improvements on analogical reasoning.

  9. 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.


    Directory of Open Access Journals (Sweden)

    Aji Widhi Wibowo


    Full Text Available The purpose of this research is to design and implement a Virtual Labolatory Materials Signal Processing Sub discussion 'Oscillator' Analog as Newspapers. Developers using the model Sutopo Ariesto Hadi (2003 as a method to produce the product. Consists of six stages: concept, design, material collecting, assembly, testing and distribution. This results in the development of Virtual media Labolatory with material 'Oscillator' with the results of 4 (four practicum digital oscillator, namely (1 Oscillator Wien Bridge, (2 Colpitts oscillator, (3 Oscillator Hartley and (4 astable multivibrator. Another result is that a user be jobsheet practicum. There are two types, namely: (1 jobsheet grip lecturers and (2 jobsheet for students. In Jobsheet there is a short book that contains the Manual on procedures for the use of virtual labolatory when practical and anatomical description of the product. Virtual Labolatory consists of the initial page (flash scren, the main page (home, pages and pages about the developer's lab referring to the story board. There are four (4 test are: (1 the truth polarity capacitor, (2 the connection (wiring, (3 mode frequency and time in the meter frequency

  11. Radiolabeled somatostatin analogs in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

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


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

  12. The MARS2013 Mars analog mission. (United States)

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


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

  13. Amino acid analogs for tumor imaging (United States)

    Goodman, Mark M.; Shoup, Timothy


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

  14. HERE, THERE, AND EVERYWHEREPublic Science Through Analogy (United States)

    Arcand, Kimberly K.


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

  15. Intracranial Fluid Redistribution During a Spaceflight Analog (United States)

    Koppelmans, Vincent; Pasternak, Ofer; Bloomberg, Jacob J.; De Dios, Yiri E.; Wood, Scott J.; Riascos, Roy; Reuter-Lorenz, Patrica A.; Kofman, Igor S.; Mulavara, Ajitkumar P.; Seidler, Rachael D.


    The neural correlates of spaceflight-induced sensorimotor impairments are unknown. Head down-tilt bed rest (HDBR) serves as a microgravity analog because it mimics the headward fluid shift and limb unloading of spaceflight. We investigated focal brain white matter (WM) changes and fluid shifts during 70 days of 6 deg HDBR in 16 subjects who were assessed pre (2x), during (3x), and post-HDBR (2x). Changes over time were compared to those in control subjects (n=12) assessed four times over 90 days. Diffusion MRI was used to assess WM microstructure and fluid shifts. Free-Water Imaging, derived from diffusion MRI, was used to quantify the distribution of intracranial extracellular free water (FW). Additionally, we tested whether WM and FW changes correlated with changes in functional mobility and balance measures. HDBR resulted in FW increases in fronto-temporal regions and decreases in posterior-parietal regions that largely recovered by two weeks post-HDBR. WM microstructure was unaffected by HDBR. FW decreased in the post-central gyrus and precuneus. We previously reported that gray matter increases in these regions were associated with less HDBR-induced balance impairment, suggesting adaptive structural neuroplasticity. Future studies are warranted to determine causality and underlying mechanisms.

  16. Natural Analog Studies at Pena Blanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    A.M. Simmons


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

  17. Interstellar and Planetary Analogs in the Laboratory (United States)

    Salama, Farid


    We present and discuss the unique capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to investigate the interaction of ionizing radiation (UV, charged particles) with molecular species (neutral molecules, radicals and ions) and carbonaceous grains in the Solar System and in the Interstellar Medium (ISM). COSmIC stands for Cosmic Simulation Chamber, a laboratory chamber where interstellar and planetary analogs are generated, processed and analyzed. It is composed of a pulsed discharge nozzle (PDN) expansion that generates a free jet supersonic expansion in a plasma cavity coupled to two ultrahigh-sensitivity, complementary in situ diagnostics: a cavity ring down spectroscopy (CRDS) system for photonic detection and a Reflectron time-of-flight mass spectrometer (ReTOF-MS) for mass detection. This setup allows the study of molecules, ions and solids under the low temperature and high vacuum conditions that are required to simulate some interstellar, circumstellar and planetary physical environments providing new fundamental insights on the molecular level into the processes that are critical to the chemistry in the ISM, circumstellar and planet forming regions, and on icy objects in the Solar System. Recent laboratory results that were obtained using COSmIC will be discussed, in particular the progress that have been achieved in monitoring in the laboratory the formation of solid particles from their gas-phase molecular precursors in environments as varied as circumstellar outflow and planetary atmospheres.

  18. 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.

  19. Resonant Tunneling Analog-To-Digital Converter (United States)

    Broekaert, T. P. E.; Seabaugh, A. C.; Hellums, J.; Taddiken, A.; Tang, H.; Teng, J.; vanderWagt, J. P. A.


    As sampling rates continue to increase, current analog-to-digital converter (ADC) device technologies will soon reach a practical resolution limit. This limit will most profoundly effect satellite and military systems used, for example, for electronic countermeasures, electronic and signal intelligence, and phased array radar. New device and circuit concepts will be essential for continued progress. We describe a novel, folded architecture ADC which could enable a technological discontinuity in ADC performance. The converter technology is based on the integration of multiple resonant tunneling diodes (RTD) and hetero-junction transistors on an indium phosphide substrate. The RTD consists of a layered semiconductor hetero-structure AlAs/InGaAs/AlAs(2/4/2 nm) clad on either side by heavily doped InGaAs contact layers. Compact quantizers based around the RTD offer a reduction in the number of components and a reduction in the input capacitance Because the component count and capacitance scale with the number of bits N, rather than by 2 (exp n) as in the flash ADC, speed can be significantly increased, A 4-bit 2-GSps quantizer circuit is under development to evaluate the performance potential. Circuit designs for ADC conversion with a resolution of 6-bits at 25GSps may be enabled by the resonant tunneling approach.

  20. Natural CO2 Analogs for Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Scott H. Stevens; B. Scott Tye


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

  1. 47 CFR 74.705 - TV broadcast analog station protection. (United States)


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

  2. 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.

  3. Can metaphors and analogies improve communication with seriously ill patients? (United States)

    Casarett, David; Pickard, Amy; Fishman, Jessica M; Alexander, Stewart C; Arnold, Robert M; Pollak, Kathryn I; Tulsky, James A


    It is not known how often physicians use metaphors and analogies, or whether they improve patients' perceptions of their physicians' ability to communicate effectively. Therefore, the objective of this study was to determine whether the use of metaphors and analogies in difficult conversations is associated with better patient ratings of their physicians' communication skills. Cross-sectional observational study of audio-recorded conversations between patients and physicians. Three outpatient oncology practices. Ninety-four patients with advanced cancer and 52 physicians. None. Conversations were reviewed and coded for the presence of metaphors and analogies. Patients also completed a 6-item rating of their physician's ability to communicate. In a sample of 101 conversations, coders identified 193 metaphors and 75 analogies. Metaphors appeared in approximately twice as many conversations as analogies did (65/101, 64% versus 31/101, 31%; sign test p < 0.001). Conversations also contained more metaphors than analogies (mean 1.6, range 0-11 versus mean 0.6, range 0-5; sign rank test p < 0.001). Physicians who used more metaphors elicited better patient ratings of communication (rho = 0.27; p = 0.006), as did physicians who used more analogies (Spearman rho = 0.34; p < 0.001). The use of metaphors and analogies may enhance physicians' ability to communicate.

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

    DEFF Research Database (Denmark)

    Bruun, Erik; Olesen, Ole


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

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

    Directory of Open Access Journals (Sweden)

    Shihui Wang

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

  6. Analysis of Attention and Analogical Reasoning in Children of Poverty (United States)

    Weatherholt, Tara N.; Harris, Ruby C.; Burns, Barbara M.; Clement, Catherine


    This study examined the relationship between specific attentional aspects of processing capacity and analogical reasoning in children from low-income families. 77 children aged 48-77 (M = 56.7) months were assessed on an analogical reasoning task (matrices subtest of the Kaufman Brief Intelligence Test) and on computerized attention tasks designed…

  7. Analogy as a means of theoretical adoption of pedagogical disciplines

    Directory of Open Access Journals (Sweden)

    Solovcova Irina A.


    Full Text Available The paper considers an application of analogy in the initial-teacher training as a tool of approaching pedagogical disciplines. The author proposes a classification of pedagogical analogies which provides choices of the most efficient model for a specific didactic situation. The article clarifies the model of the theoretical approach to pedagogical disciplines through active use of analogy, which contributes to a higher efficiency in a teacher and student interaction. The model consists of three stages: training (the stage of acquiring analogy model, the analytical stage (acquisition of pedagogical concepts, phenomena and systems through the application of analogy, and the stage of self-realization (the application of analogy method in students’ scientific-research activities considering external and internal didactic conditions which transform analogy from a teaching method into a tool for the acquisition of pedagogical disciplines. The author demonstrates that the application of analogy has a positive effect not only on the acquisition of pedagogical knowledge (especially methodic and the development of heuristic skills in students, but also on motivation for the study of pedagogical disciplines (cognitive aspect and professional pedagogical activity (formation of an individual-pedagogical attitude. .

  8. Small, low power analog-to-digital converter (United States)

    Dunn, R. D.; Fullerton, D. H.


    A small, low-power, high-speed, 8-bit analog-to-digital converter using silicon chip integrated circuits is suitable for use in airborne test data systems. The successive approximation method of analog-to-digital conversion is used to generate the digital output.

  9. 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)…

  10. Tren-based Analogs of Bacillibactin: Structure and Stability1 (United States)

    Dertz, Emily A.; Xu, Jide; Raymond, Kenneth N.


    Synthetic analogs were designed to highlight the effect of the glycine moiety of bacillibactin on the overall stability of the ferric complex as compared to synthetic analogs of enterobactin. Insertion of a variety of amino acids to catecholamide analogs based on a Tren (tris(2-aminoethyl)amine) backbone increased the overall acidity of the ligands, causing an enhancement of the stability of the resulting ferric complex as compared to TRENCAM. Solution thermodynamic behavior of these siderophores and their synthetic analogs was investigated through potentiometric and spectrophotometric titrations. X-ray crystallography, circular dichroism, and molecular modeling were used to determine the chirality and geometry of the ferric complexes of bacillibactin and its analogs. In contrast to the Tren scaffold, addition of a glycine to the catechol chelating arms causes an inversion of the trilactone backbone, resulting in opposite chiralities of the two siderophores and a destabilization of the ferric complex of bacillibactin compared to ferric enterobactin. PMID:16813410

  11. 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.

  12. NASA HRP Immunology Discipline - Use of Terrestrial Analogs (United States)

    Crucian, Brian


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

  13. Remote Sensing and Quantization of Analog Sensors (United States)

    Strauss, Karl F.


    This method enables sensing and quantization of analog strain gauges. By manufacturing a piezoelectric sensor stack in parallel (physical) with a piezoelectric actuator stack, the capacitance of the sensor stack varies in exact proportion to the exertion applied by the actuator stack. This, in turn, varies the output frequency of the local sensor oscillator. The output, F(sub out), is fed to a phase detector, which is driven by a stable reference, F(sub ref). The output of the phase detector is a square waveform, D(sub out), whose duty cycle, t(sub W), varies in exact proportion according to whether F(sub out) is higher or lower than F(sub ref). In this design, should F(sub out) be precisely equal to F(sub ref), then the waveform has an exact 50/50 duty cycle. The waveform, D(sub out), is of generally very low frequency suitable for safe transmission over long distances without corruption. The active portion of the waveform, t(sub W), gates a remotely located counter, which is driven by a stable oscillator (source) of such frequency as to give sufficient digitization of t(sub W) to the resolution required by the application. The advantage to this scheme is that it negates the most-common, present method of sending either very low level signals (viz. direct output from the sensors) across great distances (anything over one-half meter) or the need to transmit widely varying higher frequencies over significant distances thereby eliminating interference [both in terms of beat frequency generation and in-situ EMI (electromagnetic interference)] caused by ineffective shielding. It also results in a significant reduction in shielding mass.

  14. Ice megadunes on Mars: analogy with Antarctica (United States)

    Herny, Clémence; Massé, Marion; Bourgeois, Olivier; Carpy, Sabrina; Le Mouélic, Stéphane; Appéré, Thomas; Smith, Isaac; Spiga, Aymeric; Rodriguez, Sébastien


    Mass and energy balance of ice sheets are driven by complex interactions between the atmosphere and the cryosphere. Feedbacks between katabatic winds and the cryosphere may lead to the formation of sedimentation waves, so-called megadunes, at the surface of ice sheets. These have been first described in Antarctica. Here we use topographic data, optical images, and spectroscopic data acquired by Mars orbiters. We show that the surface of the Martian North Polar Cap displays two superimposed sets of sedimentation waves with differing wavelengths. These sedimentation waves have similarities with Antarctic ice megadunes regarding their surface morphology, texture, grain size, and internal stratigraphic architecture. Their shallow-dipping upwind sides, their tops and the intervening troughs are covered by young ice and occasional sastrugi fields, indicative of net accumulation. On the other hand, their steep-dipping downwind sides either expose exhumed layers of dusty old ice or correspond to smooth surfaces of coarse-grained ice, indicative of net ablation or reduced net accumulation associated with sublimation and metamorphism. These surface characteristics and the internal stratigraphic architecture revealed by radar sounding are consistent with the interpretation that both sets of Martian sedimentation waves grow and migrate upwind in response to the development of periodic accumulation/ablation patterns controlled by katabatic winds. The smaller waves, characterized by reduced net accumulation on their downwind sides, are probably analogous to the Antarctic megadunes that have been described so far. On the other hand, a terrestrial equivalent remains to be discovered for the larger ones, characterized by net ablation on their downwind sides. The recognition of these sedimentation waves provides the basis for the development of a common model of ice/wind interaction at the surface of Martian and terrestrial ice sheets and for future investigations on the respective

  15. The linguistic analogy: motivations, results, and speculations. (United States)

    Dwyer, Susan; Huebner, Bryce; Hauser, Marc D


    Inspired by the success of generative linguistics and transformational grammar, proponents of the linguistic analogy (LA) in moral psychology hypothesize that careful attention to folk-moral judgments is likely to reveal a small set of implicit rules and structures responsible for the ubiquitous and apparently unbounded capacity for making moral judgments. As a theoretical hypothesis, LA thus requires a rich description of the computational structures that underlie mature moral judgments, an account of the acquisition and development of these structures, and an analysis of those components of the moral system that are uniquely human and uniquely moral. In this paper we present the theoretical motivations for adopting LA in the study of moral cognition: (a) the distinction between competence and performance, (b) poverty of stimulus considerations, and (c) adopting the computational level as the proper level of analysis for the empirical study of moral judgment. With these motivations in hand, we review recent empirical findings that have been inspired by LA and which provide evidence for at least two predictions of LA: (a) the computational processes responsible for folk-moral judgment operate over structured representations of actions and events, as well as coding for features of agency and outcomes; and (b) folk-moral judgments are the output of a dedicated moral faculty and are largely immune to the effects of context. In addition, we highlight the complexity of the interfaces between the moral faculty and other cognitive systems external to it (e.g., number systems). We conclude by reviewing the potential utility of the theoretical and empirical tools of LA for future research in moral psychology. Copyright © 2009 Cognitive Science Society, Inc.

  16. 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

  17. Eye Movements Reveal Optimal Strategies for Analogical Reasoning. (United States)

    Vendetti, Michael S; Starr, Ariel; Johnson, Elizabeth L; Modavi, Kiana; Bunge, Silvia A


    Analogical reasoning refers to the process of drawing inferences on the basis of the relational similarity between two domains. Although this complex cognitive ability has been the focus of inquiry for many years, most models rely on measures that cannot capture individuals' thought processes moment by moment. In the present study, we used participants' eye movements to investigate reasoning strategies in real time while solving visual propositional analogy problems (A:B::C:D). We included both a semantic and a perceptual lure on every trial to determine how these types of distracting information influence reasoning strategies. Participants spent more time fixating the analogy terms and the target relative to the other response choices, and made more saccades between the A and B items than between any other items. Participants' eyes were initially drawn to perceptual lures when looking at response choices, but they nonetheless performed the task accurately. We used participants' gaze sequences to classify each trial as representing one of three classic analogy problem solving strategies and related strategy usage to analogical reasoning performance. A project-first strategy, in which participants first extrapolate the relation between the AB pair and then generalize that relation for the C item, was both the most commonly used strategy as well as the optimal strategy for solving visual analogy problems. These findings provide new insight into the role of strategic processing in analogical problem solving.

  18. Eye Movements Reveal Optimal Strategies for Analogical Reasoning

    Directory of Open Access Journals (Sweden)

    Michael S. Vendetti


    Full Text Available Analogical reasoning refers to the process of drawing inferences on the basis of the relational similarity between two domains. Although this complex cognitive ability has been the focus of inquiry for many years, most models rely on measures that cannot capture individuals' thought processes moment by moment. In the present study, we used participants' eye movements to investigate reasoning strategies in real time while solving visual propositional analogy problems (A:B::C:D. We included both a semantic and a perceptual lure on every trial to determine how these types of distracting information influence reasoning strategies. Participants spent more time fixating the analogy terms and the target relative to the other response choices, and made more saccades between the A and B items than between any other items. Participants' eyes were initially drawn to perceptual lures when looking at response choices, but they nonetheless performed the task accurately. We used participants' gaze sequences to classify each trial as representing one of three classic analogy problem solving strategies and related strategy usage to analogical reasoning performance. A project-first strategy, in which participants first extrapolate the relation between the AB pair and then generalize that relation for the C item, was both the most commonly used strategy as well as the optimal strategy for solving visual analogy problems. These findings provide new insight into the role of strategic processing in analogical problem solving.

  19. Spaceflight Sensorimotor Analogs: Simulating Acute and Adaptive Effects (United States)

    Taylor, Laura C.; Harm, Deborah L.; Kozlovskaya, Inessa; Reschke, Millard F.; Wood, Scott J.


    Adaptive changes in sensorimotor function during spaceflight are reflected by spatial disorientation, motion sickness, gaze destabilization and decrements in balance, locomotion and eye-hand coordination that occur during and following transitions between different gravitational states. The purpose of this study was to conduct a meta-synthesis of data from spaceflight analogs to evaluate their effectiveness in simulating adaptive changes in sensorimotor function. METHODS. The analogs under review were categorized as either acute analogs used to simulate performance decrements accompanied with transient changes, or adaptive analogs used to drive sensorimotor learning to altered sensory feedback. The effectiveness of each analog was evaluated in terms of mechanisms of action, magnitude and time course of observed deficits compared to spaceflight data, and the effects of amplitude and exposure duration. RESULTS. Parabolic flight has been used extensively to examine effects of acute variation in gravitational loads, ranging from hypergravity to microgravity. More recently, galvanic vestibular stimulation has been used to elicit acute postural, locomotor and gaze dysfunction by disrupting vestibular afferents. Patient populations, e.g., with bilateral vestibular loss or cerebellar dysfunction, have been proposed to model acute sensorimotor dysfunction. Early research sponsored by NASA involved living onboard rotating rooms, which appeared to approximate the time course of adaptation and post-exposure recovery observed in astronauts following spaceflight. Exposure to different bed-rest paradigms (6 deg head down, dry immersion) result in similar motor deficits to that observed following spaceflight. Shorter adaptive analogs have incorporated virtual reality environments, visual distortion paradigms, exposure to conflicting tilt-translation cues, and exposure to 3Gx centrifugation. As with spaceflight, there is considerable variability in responses to most of the analogs

  20. 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...

  1. High-speed digital-to-analog converter concepts (United States)

    Schmidt, Christian; Kottke, Christoph; Jungnickel, Volker; Freund, Ronald


    In today's fiber-optic communication systems, the bandwidth of the photonic components, i.e. modulators and photo diodes, is way greater than that of their electrical counterparts, i.e. digital-to-analog converters (DACs) and analog-to-digital converters (ADCs). In order to increase the transmission capacity, the bandwidth limitations need to be overcome. We review the progress and the recent results in the field of high-speed DACs, which are desirable for software-defined transmitters. Furthermore, we evaluate interleaving concepts regarding their ability to overcome the above mentioned limitations and demonstrate recent experimental results for a bandwidth interleaved DAC with 40 GHz analog electrical bandwidth.

  2. Figure/ground analogy for integrated sustainability & planning

    CSIR Research Space (South Africa)

    Beyers, C


    Full Text Available This article proposes a figure ground analogy as alternative way of conceptually integrating sustainability and planning. Within this framework planners are challenged to creatively consider planning practice and thought against a background...

  3. Project Birdseye Aerial Photograph Collection: Digital and Analog Materials (United States)

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

  4. Development of Venus Balloon Seismology Missions Through Earth Analog Experiments (United States)

    Krishnamoorthy, S.; Komjathy, A.; Cutts, J. A.; Pauken, M. T.; Garcia, R. F.; Mimoun, D.; Jackson, J. M.; Kedar, S.; Smrekar, S. E.; Hall, J. L.


    The study of a planet’s seismic activity is central to the understanding of its internal structure. We discuss advances made through Earth analog testing for performing remote seismology on Venus using balloons floated in the mid-atmosphere.

  5. 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.

  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 and digital signal analysis from basics to applications

    CERN Document Server

    Cohen Tenoudji, Frédéric


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

  9. Highly linear, sensitive analog-to-digital converter (United States)

    Cox, J.; Finley, W. R.


    Analog-to-digital converter converts 10 volt full scale input signal into 13 bit digital output. Advantages include high sensitivity, linearity, low quantitizing error, high resistance to mechanical shock and vibration loads, and temporary data storage capabilities.

  10. Bombesin and Neurotensin Receptor Targeting Using Radiolabeled Peptide Analogs

    NARCIS (Netherlands)

    M. de Visser (Monique)


    textabstractSomatostatin receptor-targeting peptides are widely used for imaging and therapy of neuroendocrine tumors. Peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumor patients with radiolabeled somatostatin analogs has resulted in symptomatic improvement, prolonged survival and

  11. Analogy of ISSR and RAPD markers for comparative analysis of ...

    African Journals Online (AJOL)

    Analogy of ISSR and RAPD markers for comparative analysis of genetic diversity among different Jatropha curcas genotypes. S Gupta, M Srivastava, GP Mishra, PK Naik, RS Chauhan, SK Tiwari, M Kumar, R Singh ...

  12. Physical Analog Modeling of Martian Dike-Induced Deformation (United States)

    Wyrick, D. Y.; Watson-Morris, M. J.; Morris, A. P.


    Analog models of dike injection were performed to determine style and magnitude of structural deformation associated with the dike. Primary deformation style is contraction rather than extension, indicating that martian dikes may not create grabens.

  13. On the analogy of free will and free belief


    Wagner, Verena


    Compatibilist methods borrowed from the free will debate are often used to establish doxastic freedom and epistemic responsibility. Certain analogies between the formation of intention and belief make this approach especially promising. Despite being a compatibilist myself in the practical debate, I will argue that compatibilist methods fail to establish doxastic freedom. My rejection is not based on an argument against the analogy of free will and free belief. Rather, I aim at showing that c...

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

    CERN Document Server

    Wendt, M


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


    Directory of Open Access Journals (Sweden)

    Santi Noviasari


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

  16. Synthetic analogs of anoplin show improved antimicrobial activities

    DEFF Research Database (Denmark)

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


    We present the antimicrobial and hemolytic activities of the decapeptide anoplin and 19 analogs thereof tested against methicillin-resistant Staphylococcus aureus ATCC 33591 (MRSA), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), vancomycin-resistant Enterococcus faecium (ATCC...... that increasing the charge and/or hydrophobicity improves antimicrobial activity and increases hemolytic activity. For each strain tested, we identify at least six anoplin analogs with an improved therapeutic index compared with anoplin, the only exception being Enterococcus faecium, against which only few...

  17. Fluorinated Analogs of Malachite Green: Synthesis and Toxicity

    Directory of Open Access Journals (Sweden)

    Bahram Parvin


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

  18. Functional neural correlates of fluid and crystallized analogizing. (United States)

    Geake, John G; Hansen, Peter C


    The main aim of this study was to characterize neural correlates of analogizing as a cognitive contributor to fluid and crystallized intelligence. In a previous fMRI study which employed fluid analogy letter strings as criteria in a multiple plausibility design (Geake and Hansen, 2005), two frontal ROIs associated with working memory (WM) load (within BA 9 and BA 45/46) were identified as regions in which BOLD increase correlated positively with a crystallized measure of (verbal) IQ. In this fMRI study we used fluid letter, number and polygon strings to further investigate the role of analogizing in fluid (transformation string completion) and non fluid or crystallized (unique symbol counting) cognitive tasks. The multi stimulus type (letter, number, polygon) design of the analogy strings enabled investigation of a secondary research question concerning the generalizability of fluid analogizing at a neural level. A selective psychometric battery, including the Raven's Progressive Matrices (RPM), measured individual cognitive abilities. Neural activations for the effect of task-fluid analogizing (string transformation plausibility) vs. crystallized analogizing (unique symbol counting)-included bilateral frontal and parietal areas associated with WM load and fronto parietal models of general intelligence. Neural activations for stimulus type differences were mainly confined to visually specific posterior regions. ROI covariate analyses of the psychometric measures failed to find consistent co-relationships between fluid analogizing and the RPM and other subtests, except for the WAIS Digit Symbol subtest in a group of bilateral frontal cortical regions associated with the maintenance of WM load. Together, these results support claims for separate developmental trajectories for fluid cognition and general intelligence as assessed by these psychometric subtests. Copyright 2009 Elsevier Inc. All rights reserved.


    The preparation of Adams’ most active tetrehydrocannabinol analog (Formula I, R=1,2-dimethylheptyl), and of synthetic tetrahydrocannabinol (I, R=n...beta-(3,5-dimethoxyphenyl) ethylanine. The pyrons related to tetrahydrocannabinol (II, R=n-amyl) has been reaction with aqueous ammonia to produce a high...amylphenol. An attempt will be made to condense this aminophenol with pulegone to give a nitrogen analog of tetrahydrocannabinol . The synthesis of pulegone from isopulegol has been accomplished.

  20. The Aesthetics and Establishment of Analog Post-Production


    Larkin, George


    This dissertation examines the emergence and establishment of analog post-production during the transition to sound. I analyze how the analog post-production system cannibalized the nascent post-production process of silent film, whereby the image from the filmmakers was combined with non-standardized sound produced live in the theater. Multiple forces at the theaters asserted influence over a film's presentation. Exhibitors, for example, created a de facto form of post-production by altering...

  1. Understanding Young Exoplanet Analogs with WISE (United States)

    Rice, Emily

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

  2. Immune Function Changes during a Spaceflight-Analog Undersea Mission (United States)

    Crucian, Brian; Stowe, Raymond; Mehta, Satish; Quiniarte, Heather; Yetman, Deborah; Pierson, Duane; Sams, Clarence


    There is ample evidence to suggest that space flight leads to immune system dysregulation. This may be a result of microgravity, confinement, physiological stress, radiation, environment or other mission-associated factors. It is attractive to utilize ground-based spaceflight analogs as appropriate to investigate this phenomenon. For spaceflight-associated immune dysregulation (SAID), the authors believe the most appropriate analogs might be NEEMO (short duration, Shuttle analog), Antarctic winter-over (long-duration, ISS analog) and the Haughton Mars Project in the Canadian Arctic (intermediate-duration). Each of these analogs replicate isolation, mission-associated stress, disrupted circadian rhythms, and other aspects of flight thought to contribute to SAID. To validate NEEMO as a flight analog with respect to SAID, a pilot study was conducted during the NEEMO-12 and 13 missions during 2007. Assays were performed that assessed immune status, physiological stress and latent viral reactivation. Blood and saliva samples were collected at pre-, mid-, and post-mission timepoints.

  3. Adaptive Visual Analog Scales (AVAS): A modifiable software program for the creation, administration, and scoring of visual analog scales

    National Research Council Canada - National Science Library

    Marsh-Richard, Dawn M; Hatzis, Erin S; Mathias, Charles W; Venditti, Nicholas; Dougherty, Donald M


    ... visual analog scale formats. The continuous format is a series of individual items that are rated along a solid line and scored as a percentage of distance from one of the two anchors of the rating line...

  4. Automated Cell Synthesis of Analog Integrated Circuit Layout Anasyn. (United States)

    Stanojevich, Bob Srbislav

    This thesis describes a novel model to automate cell generation for the design of analog integrated circuits and the conclusions about important features that such automation should include. This research represents the first attempt to address this problem by analyzing relevant issues of what constitutes an analog cell and how a technique can be implemented to generate these cells automatically. Our motivation for doing this is the critical limitations to circuit performance which arise from cell design. This thesis defines unique construction properties for the layout of some commonly used analog circuit topologies or cells. This thesis defines the physical layout of analog circuit cells beyond simple geometrical description. Each cell is an independent object that can be interfaced and communicated with. This thesis has extended the concept of an analog cell even further by incorporating synthesis rules into the cell definition. These rules are used to dynamically construct the optimized layout that will satisfy many of the options encountered in actual analog circuit design such as area, matching, tolerance, element rationing and parasitic components. This model can construct complex geometric shapes such as common-centroids, waffles, interdigitated, cascode etc. that are optimized at device level with the precise models for parasitic components. Furthermore, Object-Oriented implementation used in this thesis allow for easy integration of this work into other CAD tools. To demonstrate the feasibility and correctness of the ideas described in this thesis, a CAD tool ANASYN has been written. To test and demonstrate the utility and the performance developed, a variety of test cells have been generated. Data presented clearly demonstrate the uniqueness, flexibility, and precision of the analog circuit layout cells implemented in this research thesis. In addition, one test chip and one design chip have been laid out using cells generated by ANASYN and fabricated at

  5. Terrestrial stress analogs for spaceflight associated immune system dysregulation. (United States)

    Crucian, Brian; Simpson, Richard J; Mehta, Satish; Stowe, Raymond; Chouker, Alexander; Hwang, Shen-An; Actor, Jeffrey K; Salam, Alex P; Pierson, Duane; Sams, Clarence


    Recent data indicates that dysregulation of the immune system occurs and persists during spaceflight. Impairment of immunity, especially in conjunction with elevated radiation exposure and limited clinical care, may increase certain health risks during exploration-class deep space missions (i.e. to an asteroid or Mars). Research must thoroughly characterize immune dysregulation in astronauts to enable development of a monitoring strategy and validate any necessary countermeasures. Although the International Space Station affords an excellent platform for on-orbit research, access may be constrained by technical, logistical vehicle or funding limitations. Therefore, terrestrial spaceflight analogs will continue to serve as lower cost, easier access platforms to enable basic human physiology studies. Analog work can triage potential in-flight experiments and thus result in more focused on-orbit studies, enhancing overall research efficiency. Terrestrial space analogs generally replicate some of the physiological or psychological stress responses associated with spaceflight. These include the use of human test subjects in a laboratory setting (i.e. exercise, bed rest, confinement, circadian misalignment) and human remote deployment analogs (Antarctica winterover, undersea, etc.) that incorporate confinement, isolation, extreme environment, physiological mission stress and disrupted circadian rhythms. While bed rest has been used to examine the effects of physical deconditioning, radiation and microgravity may only be simulated in animal or microgravity cell culture (clinorotation) analogs. This article will characterize the array of terrestrial analogs for spaceflight immune dysregulation, the current evidence base for each, and interpret the analog catalog in the context of acute and chronic stress. Published by Elsevier Inc.

  6. Fuzzy classifier for fault diagnosis in analog electronic circuits. (United States)

    Kumar, Ashwani; Singh, A P


    Many studies have presented different approaches for the fault diagnosis with fault models having ± 50% variation in the component values in analog electronic circuits. There is still a need of the approaches which provide the fault diagnosis with the variation in the component value below ± 50%. A new single and multiple fault diagnosis technique for soft faults in analog electronic circuit using fuzzy classifier has been proposed in this paper. This technique uses the simulation before test (SBT) approach by analyzing the frequency response of the analog circuit under faulty and fault free conditions. Three signature parameters peak gain, frequency and phase associated with peak gain, of the frequency response of the analog circuit are observed and extracted such that they give unique values for faulty and fault free configuration of the circuit. The single and double fault models with the component variations from ± 10% to ± 50% are considered. The fuzzy classifier along the classification of faults gives the estimated component value under faulty and faultfree conditions. The proposed method is validated using simulated data and the real time data for a benchmark analog circuit. The comparative analysis is also presented for both the validations. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Antiplasmodial activity study of angiotensin II via Ala scan analogs. (United States)

    Silva, Adriana Farias; Bastos, Erick Leite; Torres, Marcelo Der Torossian; Costa-da-Silva, André Luis; Ioshino, Rafaella Sayuri; Capurro, Margareth Lara; Alves, Flávio Lopes; Miranda, Antonio; Vieira, Renata de Freitas Fischer; Oliveira, Vani Xavier


    Angiotensin II (AII) as well as analog peptides shows antimalarial activity against Plasmodium gallinaceum and Plasmodium falciparum, but the exact mechanism of action is still unknown. This work presents the solid-phase synthesis and characterization of eight peptides corresponding to the alanine scanning series of AII plus the amide-capped derivative and the evaluation of the antiplasmodial activity of these peptides against mature P. gallinaceum sporozoites. The Ala screening data indicates that the replacement of either the Ile(5) or the His(6) residues causes minor effects on the in vitro antiplasmodial activity compared with AII, i.e. AII (88%), [Ala(6) ]-AII (79%), and [Ala(5) ]-AII (75%). Analogs [Ala(3) ]-AII, [Ala(1) ]-AII, and AII-NH2 showed antiplasmodial activity around 65%, whereas the activity of the [Ala(8) ]-AII, [Ala(7) ]-AII, [Ala(4) ]-AII, and [Ala(2) ]-AII analogs is lower than 45%. Circular dichroism data suggest that AII and the most active analogs adopt a β-fold conformation in different solutions. All AII analogs, except [Ala(4) ]-AII and [Ala(8) ]-AII, show contractile responses and interact with the AT1 receptor, [Ala(5) ]-AII and [Ala(6) ]-AII. In conclusion, this approach is helpful to understand the contribution of each amino acid residue to the bioactivity of AII, opening new perspectives toward the design of new sporozoiticidal compounds. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  8. Transistor analogs of emergent iono-neuronal dynamics (United States)

    Rachmuth, Guy; Poon, Chi-Sang


    Neuromorphic analog metal-oxide-silicon (MOS) transistor circuits promise compact, low-power, and high-speed emulations of iono-neuronal dynamics orders-of-magnitude faster than digital simulation. However, their inherently limited input voltage dynamic range vs power consumption and silicon die area tradeoffs makes them highly sensitive to transistor mismatch due to fabrication inaccuracy, device noise, and other nonidealities. This limitation precludes robust analog very-large-scale-integration (aVLSI) circuits implementation of emergent iono-neuronal dynamics computations beyond simple spiking with limited ion channel dynamics. Here we present versatile neuromorphic analog building-block circuits that afford near-maximum voltage dynamic range operating within the low-power MOS transistor weak-inversion regime which is ideal for aVLSI implementation or implantable biomimetic device applications. The fabricated microchip allowed robust realization of dynamic iono-neuronal computations such as coincidence detection of presynaptic spikes or pre- and postsynaptic activities. As a critical performance benchmark, the high-speed and highly interactive iono-neuronal simulation capability on-chip enabled our prompt discovery of a minimal model of chaotic pacemaker bursting, an emergent iono-neuronal behavior of fundamental biological significance which has hitherto defied experimental testing or computational exploration via conventional digital or analog simulations. These compact and power-efficient transistor analogs of emergent iono-neuronal dynamics open new avenues for next-generation neuromorphic, neuroprosthetic, and brain-machine interface applications. PMID:19404469

  9. Inhibitory Effects of Resveratrol Analogs on Mushroom Tyrosinase Activity

    Directory of Open Access Journals (Sweden)

    Nádia Rezende Barbosa Raposo


    Full Text Available Skin pigmentation disorders typically involve an overproduction or uneven distribution of melanin, which results in skin spots. Resveratrol can inhibit tyrosinase, the active enzyme in the synthesis of melanin, but it does not inhibit the synthesis of melanin to an extent that enables its use alone as a skin whitening agent in pharmaceutical formulations, so its use as a coadjuvant in treatment of hyperpigmentation is suggested. Six resveratrol analogs were tested for tyrosinase inhibitory activity in vitro. Among the analogs tested, compound D was the most powerful tyrosinase inhibitor (IC50 = 28.66 µg/mL, two times more active than resveratrol (IC50 = 57.05 µg/mL, followed by the analogs A, E, B, F and C, respectively. This demonstrated that the hydroxylation at C4' on the phenolic ring was the molecular modification with most importance for the observed activity.

  10. Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing

    Energy Technology Data Exchange (ETDEWEB)

    Gaudi, B; Bennett, D; Udalski, A; Gould, A; Christie, G; Maoz, D; Dong, S; McCormick, J; Szymanski, M; Tristram, P; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; DePoy, D; Han, C; Kaspi, S; Lee, C; Mallia, F; Natusch, T; Pogge, R; Park, B; Abe, F; Bond, I; Botzler, C; Fukui, A; Hearnshaw, J; Itow, Y; Kamiya, K; Korpela, A; Kilmartin, P; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N; Sako, T; Saito, T; Sato, S; Skuljan, L; Sullivan, D; Sumi, T; Sweatman, W; Yock, P; Albrow, M; Beaulieu, J; Burgdorf, M; Cook, K; Coutures, C; Dominik, M; Dieters, S; Fouque, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B


    Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the first detection of a multiple-planet system with microlensing. We identify two planets with masses of {approx} 0.71 and {approx} 0.27 times the mass of Jupiter and orbital separations of {approx} 2.3 and {approx} 4.6 astronomical units orbiting a primary of mass {approx} 0.50 solar masses. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only 6 confirmed microlensing planet detections suggests that solar system analogs may be common.

  11. Electrothermal simulation of SOI CMOS analog integrated circuits (United States)

    Yu, Feixia; Cheng, Ming-C.


    An analytical approach, combining a heat flow device model for SOI devices and a thermal model for interconnects, is presented for electrothermal simulation of SOI analog integrated circuits. The proposed approach is able to account for large temperature gradients in device, heat exchanges between devices, heat losses from the silicon islands and interconnects to the substrate through oxide, and temperature influences on electronic characteristics. Electrothermal simulations of SOI analog integrated circuits in SPICE coupled with the proposed approach are performed and compared with the isothermal model using the BSIMSOI thermal circuit. Heat flow, thermal coupling and self-heating effects in some SOI analog integrated circuits influenced by non-isothermal effects are examined. Limitations of the BSIMSOI isothermal is discussed.

  12. Potential indications for somatostatin analogs in Cushing's syndrome. (United States)

    Arnaldi, G; Polenta, B; Cardinaletti, M; Boscaro, M


    In recent years, somatostatin analogs have been proposed and used in the diagnosis and therapy in Cushing's syndrome (CS). In these last few years, the potential therapeutic effects of somatostain analogs have been studied in different aspects of CS. The strong expression of somatostatin receptors (SSTR) type 5 in human corticotroph cells and the demonstrated efficacy of SOM230, a novel multi-ligand somatostatin analog, in inhibiting ACTH release in vitro suggest that this new drug may be effective in the treatment of ACTH hypersecretion. Very preliminary in vivo results suggest that SOM230 could be a promising drug in medical therapy for patients with Cushing's disease (CD). Prolonged treatment and more data will be needed in order to evaluate its long-term therapeutic efficacy.

  13. A hybrid digital-analog long pulse integrator

    Energy Technology Data Exchange (ETDEWEB)

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


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

  14. 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.

  15. Telomerase-inhibitory effects of sugar-modified nucleotide analogs. (United States)

    Jinmei, Hiroshi; Takahashi, Hazuki; Amano, Rie; Suzuki, Kaori; Saneyoshi, Mineo; Yamaguchi, Toyofumi


    Telomerase is an endogenous reverse transcriptase that uses its internal RNA moiety as a template for the synthesis of telomere repeats, thus maintaining telomere length. To study the susceptibility of telomerase to sugar-modified nucleotide analogs, inhibition by arabinofuranosylguanine 5'-triphosphate (araGTP), 3'-azido-2',3'-dideoxyguanosine 5'-triphosphate (AZdGTP), 2',3'-dideoxy-2'-fluoroarabino-furanosylguanine 5'-triphosphate (FaraGTP), and their thymine counterparts was investigated. Among these compounds, all dGTP analogs showed potent inhibitory activity against human telomerase. Conversely, dTTP analogs showed moderate or weak inhibition. Partially purified telomerase from cherry salmon testis utilized ddGTP and AZdGTP as substrates into the 3'-terminus of DNA.

  16. Further on integrator circuit analogy for natural convection

    Energy Technology Data Exchange (ETDEWEB)

    Khane, Vaibhav [Nuclear Engineering, Missouri University of Science and Technology, 225 Fulton Hall, 300W. 13th St., Rolla, MO-65409 (United States); Usman, Shoaib, E-mail: usmans@mst.ed [Nuclear Engineering, Missouri University of Science and Technology, 225 Fulton Hall, 300W. 13th St., Rolla, MO-65409 (United States)


    This research is an extension of the previous work on the development of an integrator (RC) circuit analogy for natural convection. This analogy has been proven experimentally as well as by numerical simulations. Additional Rayleigh-Benard convection numerical simulations were performed to investigate DELTAT (temperature difference between source and sink) dependence of the thermal resistance of a natural convection system. Our results suggest that analogous to voltage dependent resistor (VDR) in electrical engineering, DELTAT dependent thermal resistance is observed in natural convection system. This DELTAT dependent thermal resistance leads to a variable time constant. Moreover, this research also suggests that for a natural convection system, in addition to the thermal capacitance a kinetic energy capacitance also exists. The relative contribution of kinetic energy capacitance depends on Rayleigh number. These results provide significant step forward towards development of a new inexpensive modeling and transient analysis tool for a natural convection system.

  17. Diverse amide analogs of sulindac for cancer treatment and prevention. (United States)

    Mathew, Bini; Hobrath, Judith V; Connelly, Michele C; Kiplin Guy, R; Reynolds, Robert C


    Sulindac is a non-steroidal anti-inflammatory drug (NSAID) that has shown significant anticancer activity. Sulindac sulfide amide (1) possessing greatly reduced COX-related inhibition relative to sulindac displayed in vivo antitumor activity that was comparable to sulindac in a human colon tumor xenograft model. Inspired by these observations, a panel of diverse sulindac amide derivatives have been synthesized and their activity probed against three cancer cell lines (prostate, colon and breast). A neutral analog, compound 79 was identified with comparable potency relative to lead 1 and activity against a panel of lymphoblastic leukemia cell lines. Several new series also show good activity relative to the parent (1), including five analogs that also possess nanomolar inhibitory potencies against acute lymphoblastic leukemia cells. Several new analogs identified may serve as anticancer lead candidates for further development. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    K. Hajek


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

  19. An analog simulation technique for distributed flow systems

    DEFF Research Database (Denmark)

    Jørgensen, Sten Bay; Kümmel, Mogens


    Simulation of distributed flow systems in chemical engine­ering has been applied more and more during the last decade as computer techniques have developed [l]. The applications have served the purpose of identification of process dynamics and parameter estimation as well as improving process...... and process control design. Although the conventional analog computer has been expanded with hybrid techniques and digital simulation languages have appeared, none of these has demonstrated superiority in simulating distributed flow systems in general [l]. Conventional analog techniques are expensive......, especially when flow forcing and nonlinearities are simulated. Digital methods on the other. hand are time consuming. The purpose of this application note is to describe the hardware for the analog principle proposed by {2, 3]. Using this hardware ffowforcing is readily simulated, which was not feasible...

  20. The Discourse on Printed and Electronic Books: Analogies, Oppositions, and Perspectives (United States)

    Velagic, Zoran


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

  1. The Teaching-with-Analogies Model: Build Conceptual Bridges with Mental Models (United States)

    Glynn, Shawn


    Teachers often use analogies and are unaware of it--they are using them automatically. Whenever they begin an explanation with "It's just like...," "It's similar to...," or "Think of it this way...," they are using an analogy to explain a concept to their students. An "analogy" is a similarity between concepts. Analogies can help students build…

  2. The Efficacy of Interactive Analogical Models in the Instruction of Bond Energy Curves in Undergraduate Chemistry (United States)

    Shahani, Vijay M.; Jenkinson, Jodie


    We explored analogies used for introducing students to the concept of potential energy wells. Two analogy systems were developed, a spring system and a novel system consisting of electrostatic spheres. These two, distinct analogies were housed within an interactive tool that allowed students to manipulate the analogous systems and witness changes…

  3. Teamwork in high-risk environments analogous to space (United States)

    Kanki, Barbara G.


    Mountaineering expeditions combine a number of factors which make them potentially good analogs to the planetary exploration facet of long-duration space missions. A study of mountain climbing teams was conducted in order to evaluate the usefulness of the environment as a space analog and to specifically identify the factors and issues surrounding teamwork and 'successful' team performance in two mountaineering environments. This paper focuses on social/organizational factors, including team size and structure, leadership styles and authority structure which were found in the sample of 22 climb teams (122 individuals). The second major issue discussed is the construction of a valid performance measure in this high-risk environment.

  4. Dual chain synthetic heparin-binding growth factor analogs

    Energy Technology Data Exchange (ETDEWEB)

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


    The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  5. Acoustic analog of monolayer graphene and edge states (United States)

    Zhong, Wei; Zhang, Xiangdong


    Acoustic analog of monolayer graphene has been designed by using silicone rubber spheres of honeycomb lattices embedded in water. The dispersion of the structure has been studied theoretically using the rigorous multiple-scattering method. The energy spectra with the Dirac point have been verified and zigzag edge states have been found in ribbons of the structure, which are analogous to the electronic ones in graphene nanoribbons. The guided modes along the zigzag edge excited by a point source have been numerically demonstrated. The open cavity and “Z” type edge waveguide with 60° corners have also been realized by using such edge states.

  6. 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.

  7. Mengolah Data Video Analog menjadi Video Digital Sederhana

    Directory of Open Access Journals (Sweden)

    Nick Soedarso


    Full Text Available Nowadays, editing technology has entered the digital age. Technology will demonstrate the evidence of processing analog to digital data has become simpler since editing technology has been integrated in the society in all aspects. Understanding the technique of processing analog to digital data is important in producing a video. To utilize this technology, the introduction of equipments is fundamental to understand the features. The next phase is the capturing process that supports the preparation in editing process from scene to scene; therefore, it will become a watchable video.   

  8. The Use of Reformation to Repair Faulty Analogical Blends


    Bundy, Alan; Maclean, Ewen


    An analogical blend is the formation of a new concept from two old ones, e.g., houseboat or boathouse from house and boat, depending on whether you align the boat with the house or its occupant. This process can be automated via the colimit algorithm from Category Theory, applied to two ontologies, plus an initial alignment between their terms. Analogical blends are often faulty, e.g. inconsistent or incomplete, so need to be repaired. Reformation is an algorithm we have developed for the dia...

  9. Developing a 300C Analog Tool for EGS

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy


    This paper covers the development of a 300°C geothermal well monitoring tool for supporting future EGS (enhanced geothermal systems) power production. This is the first of 3 tools planed. This is an analog tool designed for monitoring well pressure and temperature. There is discussion on 3 different circuit topologies and the development of the supporting surface electronics and software. There is information on testing electronic circuits and component. One of the major components is the cable used to connect the analog tool to the surface.

  10. High-speed analog-to-digital conversion

    CERN Document Server

    Demler, Michael J


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

  11. Synthesis of I-125 labeled photoaffinity rapamycin analogs

    Energy Technology Data Exchange (ETDEWEB)

    Shu, A.Y.L.; Yamashita, D.S.; Holt, D.A.; Heys, J.R. [SmithKline Beecham Pharmaceuticals, King of Prussia, PA (United States)


    Two no-carrier-added {sup 125}I-labelled photoaffinity rapamycin analogs were prepared: 7-demethoxy-7-(4-azido-3-{sup 125}I-benzyloxy) rapamycin and its C{sub 28}-C{sub 29} seco analog. The key reactions of the synthesis were substitution of the C{sub 7} methoxyl of rapamycin with 4-azido-3-tributylstannylbenzyloxy group, exchange of tributyltin with {sup 125}I using Na{sup 125}I and Chloramine-T, and a ZnCl{sub 2} mediated retro-Aldol cleavage of the C{sub 28}-C{sub 29} bond of rapamycin. (author).

  12. Dual chain synthetic heparin-binding growth factor analogs (United States)

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


    The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  13. Artificial intelligence methods in diagnostics of analog systems

    Directory of Open Access Journals (Sweden)

    Bilski Piotr


    Full Text Available The paper presents the state of the art and advancement of artificial intelligence methods in analog systems diagnostics. Firstly, the diagnostic domain is introduced and its problems explained. Then, computational intelligence approaches usable for fault detection and identification are reviewed. Particular groups of methods are presented in detail, explaining their usefulness and drawbacks. Examples, such as the induction motor or the electronic filter, are provided to show the applicability of the presented approaches for monitoring the state of analog objects from engineering domains. The discussion section reviews the presented approaches, their future prospects and problems to be solved.

  14. Foucault's Pendulum, Analog for an Electron Spin State (United States)

    Linck, Rebecca


    The classical Lagrangian that describes the coupled oscillations of Foucault's pendulum presents an interesting analog to an electron's spin state in an external magnetic field. With a simple modification, this classical Lagrangian yields equations of motion that directly map onto the Schrodinger-Pauli Equation. This analog goes well beyond the geometric phase, reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured 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.

  15. 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.

  16. Historians and miracles: The principle of analogy and antecedent ...

    African Journals Online (AJOL)

    I present a positive case for the historian's right to adjudicate on miracle claims and address two major objections to this conclusion: the principle of analogy and antecedent probability. At times I use the resurrection of Jesus as an example. This is the first of two articles. In the second, I will address three additional common ...

  17. Time-interleaved Analog-to-Digital Converters

    NARCIS (Netherlands)

    Louwsma, S.M.


    This thesis describes the feasibility of an analog-to-digital converter (ADC) with a sample-rate of 1-2 GS/s, a resolution of 8-10 bits, and a state-of-the-art power efficiency of less than 1 pJ/conversion step. The time-interleaved architecture exploits parallelism to increase the sample-rate while

  18. Analogies between continuum dislocation theory, continuum mechanics and fluid mechanics (United States)

    Silbermann, C. B.; Ihlemann, J.


    Continuum Dislocation Theory (CDT) relates gradients of plastic deformation in crystals with the presence of geometrically necessary dislocations. Interestingly, CDT shows striking analogies to other branches of continuum mechanics. The present contribution demonstrates this on two essential kinematical quantities which reflect tensorial dislocation properties: the (resultant) Burgers vector and the dislocation density tensor. First, the limiting process for the (resultant) Burgers vector from an integral to a local quantity is performed analogously to the limiting process from the force vector to the traction vector. By evaluating the balance of forces on a tetrahedral volume element, Cauchy found his famous formula relating traction vector and stress tensor. It is shown how this procedure may be adopted to a continuously dislocated tetrahedron. Here, the conservation of Burger’s vector implicates the introduction of the dislocation density tensor. Second, analogies between the plastic flow of a continuously dislocated solid and the liquid flow of a fluid are highlighted: the resultant Burgers vector of a dislocation ensemble plays a similar role as the (resultant) circulation of a vortex tube. Moreover, both vortices within flowing fluids and dislocations within deforming solids induce discontinuities in the velocity field and the plastic distortion field, respectively. Beyond the analogies, some peculiar properties of the dislocation density tensor are presented as well.

  19. Using an analogy in the introduction of a portfolio

    NARCIS (Netherlands)

    van Tartwijk, Jan; van Rijswijk, Martine; Tuithof, Hanneke; Driessen, Erik W.


    Students in many teacher education programmes experience confusion about portfolios. This study investigated whether using an analogy in the introduction of a portfolio helps teacher education students understand both the purpose of a portfolio and how to compile it. It was also investigated whether

  20. Digitally assisted analog beamforming for millimeter-wave communication

    NARCIS (Netherlands)

    Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria


    The paper addresses the research question on how digital beamsteering algorithms can be combined with analog beamforming in the context of millimeter-wave communication for next generation (5G) cellular systems. Key is the use of coarse quantisation of the individual antenna signals next to the

  1. Quantum Analogs of Tensor Product Representations of su(1; 1)*

    NARCIS (Netherlands)

    Groenevelt, W.


    Abstract. We study representations of Uq(su(1; 1)) that can be considered as quantum analogs of tensor products of irreducible -representations of the Lie algebra su(1; 1). We determine the decomposition of these representations into irreducible -representations of Uq(su(1; 1)) by diagonalizing the

  2. Configurable analog-digital conversion using the neural engineering framework. (United States)

    Mayr, Christian G; Partzsch, Johannes; Noack, Marko; Schüffny, Rene


    Efficient Analog-Digital Converters (ADC) are one of the mainstays of mixed-signal integrated circuit design. Besides the conventional ADCs used in mainstream ICs, there have been various attempts in the past to utilize neuromorphic networks to accomplish an efficient crossing between analog and digital domains, i.e., to build neurally inspired ADCs. Generally, these have suffered from the same problems as conventional ADCs, that is they require high-precision, handcrafted analog circuits and are thus not technology portable. In this paper, we present an ADC based on the Neural Engineering Framework (NEF). It carries out a large fraction of the overall ADC process in the digital domain, i.e., it is easily portable across technologies. The analog-digital conversion takes full advantage of the high degree of parallelism inherent in neuromorphic networks, making for a very scalable ADC. In addition, it has a number of features not commonly found in conventional ADCs, such as a runtime reconfigurability of the ADC sampling rate, resolution and transfer characteristic.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gustafson, D.L. [Consulting Economic Geologist, Reno, NV (United States)


    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.

  4. Natural analogs for far-field environment/hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Hoxie, D.T. [Geological Survey, Denver, CO (United States)


    This paper discusses the applicability of natural-analog studies to characterize far-field conditions in the vicinity of geologic repository systems for the disposal of high-level radioactive wastes. Conditions in the far field are determined by the natural state and evolution of the repository geosphere and its environment.

  5. 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.

  6. Difference in brain activations during appreciating paintings and photographic analogs (United States)

    Mizokami, Yoshinori; Terao, Takeshi; Hatano, Koji; Hoaki, Nobuhiko; Kohno, Kentaro; Araki, Yasuo; Kodama, Kensuke; Makino, Mayu; Izumi, Toshihiko; Shimomura, Tsuyoshi; Fujiki, Minoru; Kochiyama, Takanori


    Several studies have investigated neural correlates of aesthetic appreciation for paintings but to date the findings have been heterogeneous. This heterogeneity may be attributed to previous studies’ measurement of aesthetic appreciation of not only the beauty of paintings but also the beauty of motifs of the paintings. In order to better elucidate the beauty of paintings, it seems necessary to compare aesthetic appreciation of paintings and photographic analogs which included corresponding real images. We prepared for famous painters’ pictures and their photographic analogs which were set up to resemble each painting in order to investigate the hypothesis that there exist specific neural correlates associated with the aesthetic appreciation for paintings. Forty-four subjects participated in functional magnetic resonance study which required comparisons of aesthetic appreciation of paintings of still life and landscape versus photographic analogs including corresponding real images of still life and landscape. Bilateral cuneus and the left lingual gyrus were activated in the comparison of aesthetic appreciation of paintings versus photographic analogs. In conclusion, the present findings suggest a possibility of the existence of specific neural correlates associated with the aesthetic appreciation for paintings and that bilateral cuneus and the left lingual gyrus may be involved. PMID:25071508

  7. Baboons, like humans, solve analogy by categorical abstraction of relations. (United States)

    Flemming, Timothy M; Thompson, Roger K R; Fagot, Joël


    Reasoning by analogy is one of the most complex and highly adaptive cognitive processes in abstract thinking. For humans, analogical reasoning entails the judgment and conceptual mapping of relations-between-relations and is facilitated by language (Gentner in Cogn Sci 7:155-170, 1983; Premack in Thought without language, Oxford University Press, New York, 1986). Recent evidence, however, shows that monkeys like "language-trained" apes exhibit similar capacity to match relations-between-relations (Fagot and Thompson in Psychol Sci 22:1304-1309, 2011; Flemming et al. in J Exp Psychol: Anim Behav Process 37:353-360, 2011; Truppa et al. in Plos One 6(8):e23809, 2011). Whether this behavior is driven by the abstraction of categorical relations or alternatively by direct perception of variability (entropy) is crucial to the debate as to whether nonhuman animals are capable of analogical reasoning. In the current study, we presented baboons (Papio papio) and humans (Homo sapiens) with a computerized same/different relational-matching task that in principle could be solved by either strategy. Both baboons and humans produced markedly similar patterns of responding. Both species responded different when the perceptual variability of a stimulus array fell exactly between or even closer to that of a same display. Overall, these results demonstrate that categorical abstraction trumped perceptual properties and, like humans, Old World monkeys can solve the analogical matching task by judging the categorical abstract equivalence of same/different relations-between-relations.

  8. 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.

  9. Varieties of noise: analogical reasoning in synthetic biology. (United States)

    Knuuttila, Tarja; Loettgers, Andrea


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

  10. Chemoselective PEGylation of Cysteine Analogs of Human Basic ...

    African Journals Online (AJOL)

    electrophoresis [SDS-PAGE]. Stability of. PEGylated and non-PEGylated forms of hbFGF cysteine analog was studied by incubating them in the presence of denaturing agent such as guanidine HCl at 37 °C for 24 h. The effect of such reagent was determined by fluorescence spectrophotometry (Luminescence spectrometer.

  11. A spin-4 analog of 3D massive gravity

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Kovacevic, Marija; Rosseel, Jan; Townsend, Paul K.; Yin, Yihao


    A sixth-order, but ghost-free, gauge-invariant action is found for a fourth-rank symmetric tensor potential in a three-dimensional (3D) Minkowski spacetime. It propagates two massive modes of spin 4 that are interchanged by parity and is thus a spin-4 analog of linearized 'new massive gravity'. Also

  12. The Nitty Gritty: How We Make Analogs Work (United States)

    Self, A. L.; Huppman, S. R.; Spence, L. A.


    NASA's Human Research Program (HRP) is becoming increasingly reliant on Isolated, Confined and Controlled (ICC) analogs to accomplish many of its research objectives. Compared to other research platforms, ICC analogs present a unique set of operational challenges that must be addressed in order to ensure a high fidelity research environment. In particular, the Human Exploration Research Analog (HERA) habitat, which is classified as an ICC environment, has been developed over the past three years to accommodate the operational needs of research investigations from each of the HRP Elements. During the development period, various types of requirements have contributed to the current operational model, which strives to achieve the highest possible level of mission fidelity with limited resources. This presentation will focus on the operational aspects of the HERA habitat, with emphasis on how we develop the analog research environment to meet researchers' needs. Specific discussion topics include mission scenario development, operational tasks, mission timeline integration, stressor implementation, console support, and improvements based on lessons learned. The information is intended to help investigators better understand the details behind HERA operations and the benefits to their research goals.

  13. A Total Dose Characterization of Five Commercial Analog Multiplexers. (United States)


    Laboratory, Kirtland Air Force Base, New Mexico , under Job Order 88091145. First Lieutenant Mark R. Ackermann (NTCT) was the Laboratory Project Officer-in...b) the channel resistance R for an n-channel MOS rET. * 25 AFWL-TR-84-07 Vino +5 OTL Figure 8. A CMOS analog transfer gate. VT,, 0 DOSE Figure 9

  14. Inhibition of Delta-induced Notch signaling using fucose analogs. (United States)

    Schneider, Michael; Kumar, Vivek; Nordstrøm, Lars Ulrik; Feng, Lei; Takeuchi, Hideyuki; Hao, Huilin; Luca, Vincent C; Garcia, K Christopher; Stanley, Pamela; Wu, Peng; Haltiwanger, Robert S


    Notch is a cell-surface receptor that controls cell-fate decisions and is regulated by O-glycans attached to epidermal growth factor-like (EGF) repeats in its extracellular domain. Protein O-fucosyltransferase 1 (Pofut1) modifies EGF repeats with O-fucose and is essential for Notch signaling. Constitutive activation of Notch signaling has been associated with a variety of human malignancies. Therefore, tools that inhibit Notch activity are being developed as cancer therapeutics. To this end, we screened L-fucose analogs for their effects on Notch signaling. Two analogs, 6-alkynyl and 6-alkenyl fucose, were substrates of Pofut1 and were incorporated directly into Notch EGF repeats in cells. Both analogs were potent inhibitors of binding to and activation of Notch1 by Notch ligands Dll1 and Dll4, but not by Jag1. Mutagenesis and modeling studies suggest that incorporation of the analogs into EGF8 of Notch1 markedly reduces the ability of Delta ligands to bind and activate Notch1.

  15. Vitamin D analogs for the treatment of secondary hyperparathyroidism. (United States)

    Slatopolsky, Eduardo; Brown, Alex J


    Calcitriol controls parathyroid gland (PTG) growth and suppresses the synthesis and secretion of PTH. However, because of its potent effects on intestinal calcium and phosphorus absorption and bone mobilization, calcitriol treatment can induce hypercalcemia and hyperphosphatemia often precluding its use at therapeutic doses. In the past decade, several vitamin D analogs have been developed. These analogs retain the action on the PTG while having less effect on calcium and phosphorus. Most of these analogs for the treatment of secondary hyperparathyroidism (SH) have a modification on the side chain of calcitriol. In the USA, two vitamin D analogs 19-nor 1,25(OH)(2)D(2) and 1 alpha(OH)D(2) are currently used for the treatment of SH. Studies in animals demonstrated that 19-nor-1,25(OH)(2)D(2) is less calcemic and phosphatemic than 1 alpha(OH)D(2). The lower Ca x P product in 19-nor-1,25(OH)(2)D(2)-treated rats may be an important consideration in patient therapy. Further studies in patients are necessary to define these differences. Copyright 2002 S. Karger AG, Basel

  16. Mountain range specific analog weather forecast model for ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 117; Issue 5. Mountain range specific ... Mountain range specific analog weather forecast model is developed utilizing surface weather observations of reference stations in each mountain range in northwest Himalaya (NW-Himalaya).The model searches past ...


    Energy Technology Data Exchange (ETDEWEB)

    Kane, Stephen R. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); Kopparapu, Ravi Kumar [Department of Geosciences, Penn State University, 443 Deike Building, University Park, PA 16802 (United States); Domagal-Goldman, Shawn D., E-mail: [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)


    The field of exoplanetary science has seen a dramatic improvement in sensitivity to terrestrial planets over recent years. Such discoveries have been a key feature of results from the Kepler mission which utilizes the transit method to determine the size of the planet. These discoveries have resulted in a corresponding interest in the topic of the Habitable Zone and the search for potential Earth analogs. Within the solar system, there is a clear dichotomy between Venus and Earth in terms of atmospheric evolution, likely the result of the large difference (approximately a factor of two) in incident flux from the Sun. Since Venus is 95% of the Earth's radius in size, it is impossible to distinguish between these two planets based only on size. In this Letter we discuss planetary insolation in the context of atmospheric erosion and runaway greenhouse limits for planets similar to Venus. We define a ''Venus Zone'' in which the planet is more likely to be a Venus analog rather than an Earth analog. We identify 43 potential Venus analogs with an occurrence rate (η{sub ♀}) of 0.32{sub −0.07}{sup +0.05} and 0.45{sub −0.09}{sup +0.06} for M dwarfs and GK dwarfs, respectively.

  18. 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

  19. Inherently analog quantity representations in olive baboons (Papio anubis

    Directory of Open Access Journals (Sweden)

    Allison M Barnard


    Full Text Available Strong evidence indicates that non-human primates possess a numerical representation system, but the inherent nature of that system is still debated. Two cognitive mechanisms have been proposed to account for non-human primate numerical performance: (1 a discrete object-file system limited to quantities <4, and (2 an analog system which represents quantities comparatively but is limited by the ratio between two quantities. To test the underlying nature of non-human primate quantification, we asked eight experiment -naive olive baboons (Papio anubis to discriminate between number pairs containing small (<4, large (>4, or span (small vs. large numbers of food items presented simultaneously or sequentially. The prediction from the object-file hypothesis is that baboons will only accurately choose the larger quantity in small pairs, but not large or span pairs. Conversely, the analog system predicts that baboons will be successful with all numbers, and that success will be dependent on numerical ratio. We found that baboons successfully discriminated all pair types at above chance levels. In addition, performance significantly correlated with the ratio between the numerical values. Although performance was better for simultaneous trials than sequential trials, evidence favoring analog numerical representation emerged from both conditions, and was present even in the first exposure to number pairs. Together, these data favor the interpretation that a single, coherent analog representation system underlies spontaneous quantitative abilities in primates.

  20. Beyond Analog Gravity: The Case of Exceptional Dynamics

    CERN Document Server

    Novello, M


    We show that it is possible to go beyond the simple kinematical aspects of the analog models of gravity. We exhibit the form of the Lagrangian that describes the dynamics of a self-interacting field $ \\phi $ as an interaction between $ \\phi $ and its associated effective metric $ \\hat{g}^{\\mu\

  1. Present and future trends in integrated analog signal processing circuits (United States)

    Nakayama, Kenji; Iwata, Atsushi; Yanagisawa, Takeshi


    An overview is presented of the recent and future trends in the design and applications of integrated analog signal processing circuits. Design techniques are reviewed for operational amplifiers, monolithic bipolar active RC circuits, switched-capacitor (SC) circuits, continuous-time MOS circuits, and analog-to-digital converters (ADCs). High-frequency filter realization, up to 100 MHz, has been attempted by bipolar active RC circuits and GaAs circuits. Improved design techniques for SC circuits are proposed. A multistage noise shaping ADC is very useful to integrate an accurate ADC. A high SNR (more than 91 dB) is obtained by the three-stage ADC, which can be applied to digital audio systems. An overview is presented of silicon compilers for SC circuits. A mixed analog/digital master slice LSI is proposed to simplify an LSI customizing process. A voice-band modem LSI has been developed, resulting in good filter responses and SNR. Finally, promising applications of integrated analog circuits are briefly reviewed.

  2. 700-MHz switched-capacitor analog waveform sampling circuit (United States)

    Haller, Gunther M.; Wooley, Bruce A.


    Analog switched-capacitor memory circuits are suitable for use in a wide range of applications where analog waveforms must be captured or delayed, such as the recording of pulse echo events and pulse shapes. Analog sampling systems based on switched-capacitor techniques offer performance superior to that of flash A/D converters and charge-coupled devices with respect to cost, density, dynamic range, sampling speed, and power consumption. This paper proposes an architecture with which sampling frequencies of several hundred megahertz can be achieved using conventional CMOS technology. Issues concerning the design and implementation of an analog memory circuit based on the proposed architecture are presented. An experimental two-channel memory with 32 sampling cells in each channel has been integrated in a 2-micron CMOS technology with poly-to-poly capacitors. The measured nonlinearity of this prototype is 0.03% for a 2.5 V input range, and the memory cell gain matching is 0.01% rms. The dynamic range of the memory exceeds 12 b for a sampling frequency of 700 MHz. The power dissipation for one channel operated from a single + 5 V supply is 2 mW.

  3. Great Computational Intelligence in the Formal Sciences via Analogical Reasoning (United States)


    9 6 The Analogs Used in Our Model ...Overview of the Architecture of πVivid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 17...made about Watson, the Jeopardy! -winning AI system.2 We launched the GCI research program to change the landscape , dramatically. When Phase 1 of the

  4. Metaphors & Analogies: Power Tools for Teaching Any Subject (United States)

    Wormeli, Rick


    Metaphors and analogies are more than figurative language suitable only for English classes and standardized test questions. They are "power tools" that can electrify learning in every subject and at all grade levels. Metaphors show students how to make connections between the concrete and the abstract, prior knowledge and unfamiliar concepts, and…

  5. Industrial and Biological Analogies Used Creatively by Business Professionals (United States)

    Kennedy, Emily B.; Miller, Derek J.; Niewiarowski, Peter H.


    The objective of this study was to test the effect of far-field industrial (i.e., man-made) versus biological analogies on creativity of business professionals from two organizations engaged in the idea generation phase of new product development. Psychological effects, as reflected in language use, were measured via computerized text analysis of…

  6. Analysis of a developed analog trilateration system of impulsive sounds (United States)

    López R., Juan Manuel; Marulanda B., Jose Ignacio


    A characterization study is made from a trilateration system for impulsive sounds, in which theoretical analysis and experimental results are presented. This system uses an analog trilateration method, avoiding to implement high frequency ADC conversion elements. It also presents the optimization of the chosen array of microphones, thus allowing for a better trilateration algorithm behavior.

  7. Graphene-on-semiconductor substrates for analog electronics (United States)

    Lagally, Max G.; Cavallo, Francesca; Rojas-Delgado, Richard


    Electrically conductive material structures, analog electronic devices incorporating the structures and methods for making the structures are provided. The structures include a layer of graphene on a semiconductor substrate. The graphene layer and the substrate are separated by an interfacial region that promotes transfer of charge carriers from the surface of the substrate to the graphene.

  8. Visual analog rating of mood by people with aphasia. (United States)

    Haley, Katarina L; Womack, Jennifer L; Harmon, Tyson G; Williams, Sharon W


    Considerable attention has been given to the identification of depression in stroke survivors with aphasia, but there is more limited information about other mood states. Visual analog scales are often used to collect subjective information from people with aphasia. However, the validity of these methods for communicating about mood has not been established in people with moderately to severely impaired language. The dual purposes of this study were to characterize the relative endorsement of negative and positive mood states in people with chronic aphasia after stroke and to examine congruent validity for visual analog rating methods for people with a range of aphasia severity. Twenty-three left-hemisphere stroke survivors with aphasia were asked to indicate their present mood by using two published visual analog rating methods. The congruence between the methods was estimated through correlation analysis, and scores for different moods were compared. Endorsement was significantly stronger for "happy" than for mood states with negative valence. At the same time, several participants displayed pronounced negative mood compared to previously published norms for neurologically healthy adults. Results from the two rating methods were moderately and positively correlated. Positive mood is prominent in people with aphasia who are in the chronic stage of recovery after stroke, but negative moods can also be salient and individual presentations are diverse. Visual analog rating methods are valid methods for discussing mood with people with aphasia; however, design optimization should be explored.

  9. Three-channel integrating analog-to-digital converter (United States)

    Stevens, G. L.


    A three-channel integrating analog-to-digital converter was added to the complex mixer system to accept the baseband, complex signals generated by the complex mixers and output binary data to the digital demodulator for further processing and recording. The converter was first used for processing multistation data in radar experiments in the spring of 1977.

  10. The Pulley Analogy Does Not Work for Every Siphon (United States)

    Planinsic, Gorazd; Slisko, Josip


    How do siphons work? Some see atmospheric pressure, explicitly or implicitly, as a crucial factor in siphon action. Others explain that a siphon works due to a difference of water weights in unequal arms. According to the latter view, siphon action is analogous to the action of a pulley or to the behaviour of a chain that is moving over a tube. In…

  11. Wavelet-based analogous phase scintillation index for high latitudes (United States)

    Ahmed, A.; Tiwari, R.; Strangeways, H. J.; Dlay, S.; Johnsen, M. G.


    The Global Positioning System (GPS) performance at high latitudes can be severely affected by the ionospheric scintillation due to the presence of small-scale time-varying electron density irregularities. In this paper, an improved analogous phase scintillation index derived using the wavelet-transform-based filtering technique is presented to represent the effects of scintillation regionally at European high latitudes. The improved analogous phase index is then compared with the original analogous phase index and the phase scintillation index for performance comparison using 1 year of data from Trondheim, Norway (63.41°N, 10.4°E). This index provides samples at a 1 min rate using raw total electron content (TEC) data at 1 Hz for the prediction of phase scintillation compared to the scintillation monitoring receivers (such as NovAtel Global Navigation Satellite Systems Ionospheric Scintillation and TEC Monitor receivers) which operate at 50 Hz rate and are thus rather computationally intensive. The estimation of phase scintillation effects using high sample rate data makes the improved analogous phase index a suitable candidate which can be used in regional geodetic dual-frequency-based GPS receivers to efficiently update the tracking loop parameters based on tracking jitter variance.

  12. An Efficient Synthesis of Enantiopure (R-heteroarylpyrimidine Analogs

    Directory of Open Access Journals (Sweden)

    Guo-Ming Zhao


    Full Text Available An efficient synthesis of enantiopure (R-heteroarylpyrimidine analogs is described here, which involves introduction of a chiral group, formation and separation of diasteroisomers and final transformation of an amide to an ester. The absolute configuration of the enantiopure HAPs is confirmed by X-ray analysis of their intermediates.

  13. The Resilience of Analog Tools in Creative Work Practices

    DEFF Research Database (Denmark)

    Borum, Nanna; Petersson, Eva; Frimodt-Møller, Søren


    This paper discusses the use of digital and analog tools, respectively, in a creative industry. The research was done within the EU-funded research project IdeaGarden, which explores digital platforms for creative collaboration. The findings in a case study of LEGO® Future Lab, one of LEGO Group’...

  14. Antiangiogenic effects of synthetic analogs of curcumin in vivo ...

    African Journals Online (AJOL)

    The active compound curcumin is isolated from the spice turmeric. Curcumin, curcuminoids and their synthetic analogs have been shown to inhibit the progression of cancer in animal models. In colon and skin carcinogenesis the genetic changes engross different genes, but curcumin is effective in preventing ...

  15. Antiangiogenic Effects of Synthetic Analogs of Curcumin in vivo

    African Journals Online (AJOL)

    Dr Femi Olaleye

    The active compound curcumin is isolated from the spice turmeric. Curcumin, curcuminoids and their synthetic analogs have been shown to inhibit the progression of cancer in animal models. In colon and skin carcinogenesis the genetic changes engross different genes, but curcumin is effective in preventing ...

  16. 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.


    -spectroscopy. All the synthesized carbendazim analogs were screened for their in vitro antimicrobial activity against different Gram-positive (Staphylococcus aureus and Micrococcus luteus), Gram-negative (Escherichia coli and Klebsiella pneumonia) bacteria, fungi (Fusarium solani and Fusarium oxysporu) and in vivo...

  17. Antimicrobial and cell-penetrating properties of penetratin analogs

    DEFF Research Database (Denmark)

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


    Cell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) show great potential as drug delivery vectors and new antibiotic drug entities, respectively. The current study deals with the properties of a variety of peptide analogs derived from the well-known CPP penetratin as well as octaar......Cell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) show great potential as drug delivery vectors and new antibiotic drug entities, respectively. The current study deals with the properties of a variety of peptide analogs derived from the well-known CPP penetratin as well...... as octaarginine and different Tat sequences. The effects of peptide length, guanidinium content, and sequence of non-cationic residues were assessed in mammalian and bacterial cells. The arginine (Arg) content in the penetratin analogs was found to influence eukaryotic cell uptake efficiency, antimicrobial...... was similar, the eukaryotic cellular uptake of the shuffled analogs was noticeably lower than for native penetratin. Moreover, a point substitution of Met to Leu in native penetratin had no influence on eukaryotic cellular uptake and antimicrobial effect, and only a minor effect on cytotoxicity, in contrast...

  18. Effects of mathematical game and instructional analogy as advance ...

    African Journals Online (AJOL)

    The study investigated the effects of mathematical game and instructional analogy on students' achievement in junior secondary school mathematics. A total of 246 Junior Secondary Two (JS2) Mathematics students were involved in the study. A 3×2 factorial design was adopted in the research. From the findings, it was ...

  19. Descartes highlands: Possible analogs around the Orientale Basin, part D (United States)

    Carroll, A. H.


    Two possible analogs, although not entirely satisfactory, offer reasonable alternatives to the volcanic interpretation of the Descartes highlands. Reconsideration of this complex terrain, prompted by the preliminary results of the Apollo 16 mission, will lead to the revision of some theories on lunar volcanism and also to a better understanding of the landforms caused by the formation of multi-ring basins.

  20. Analog neural network-based helicopter gearbox health monitoring system. (United States)

    Monsen, P T; Dzwonczyk, M; Manolakos, E S


    The development of a reliable helicopter gearbox health monitoring system (HMS) has been the subject of considerable research over the past 15 years. The deployment of such a system could lead to a significant saving in lives and vehicles as well as dramatically reduce the cost of helicopter maintenance. Recent research results indicate that a neural network-based system could provide a viable solution to the problem. This paper presents two neural network-based realizations of an HMS system. A hybrid (digital/analog) neural system is proposed as an extremely accurate off-line monitoring tool used to reduce helicopter gearbox maintenance costs. In addition, an all analog neural network is proposed as a real-time helicopter gearbox fault monitor that can exploit the ability of an analog neural network to directly compute the discrete Fourier transform (DFT) as a sum of weighted samples. Hardware performance results are obtained using the Integrated Neural Computing Architecture (INCA/1) analog neural network platform that was designed and developed at The Charles Stark Draper Laboratory. The results indicate that it is possible to achieve a 100% fault detection rate with 0% false alarm rate by performing a DFT directly on the first layer of INCA/1 followed by a small-size two-layer feed-forward neural network and a simple post-processing majority voting stage.

  1. Analog Video Authentication and Seal Verification Equipment Development

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Lancaster


    Under contract to the US Department of Energy in support of arms control treaty verification activities, the Savannah River National Laboratory in conjunction with the Pacific Northwest National Laboratory, the Idaho National Laboratory and Milagro Consulting, LLC developed equipment for use within a chain of custody regime. This paper discussed two specific devices, the Authentication Through the Lens (ATL) analog video authentication system and a photographic multi-seal reader. Both of these devices have been demonstrated in a field trial, and the experience gained throughout will also be discussed. Typically, cryptographic methods are used to prove the authenticity of digital images and video used in arms control chain of custody applications. However, in some applications analog cameras are used. Since cryptographic authentication methods will not work on analog video streams, a simple method of authenticating analog video was developed and tested. A photographic multi-seal reader was developed to image different types of visual unique identifiers for use in chain of custody and authentication activities. This seal reader is unique in its ability to image various types of seals including the Cobra Seal, Reflective Particle Tags, and adhesive seals. Flicker comparison is used to compare before and after images collected with the seal reader in order to detect tampering and verify the integrity of the seal.

  2. Implementation of KRoC on Analog Devices' "SHARC" DSP

    NARCIS (Netherlands)

    Otten, G.W.; Schwirtz, M.H.; Schwirtz, Marcellinus H.; Bruis, R.; Bruis, R.; Broenink, Johannes F.; Bakkers, André; O'Neill, Brian C.


    This paper summarises the experiences gained at the Control Laboratory of the University of Twente in porting the Kent Retargetable occam Compiler -KroC -to the Analog Devices' ADSP21060 SHARC Digital Signal Processor. The choice of porting the KRoC to the DSP processor was in our view both a

  3. Analog Modeling of Normal Fault Growth on Mars (United States)

    Wyrick, D. Y.; Morris, A. P.; Ferrill, D. A.


    Physical analog modeling and analyses of martian fault systems support the interpretation that simple faults on Mars do not grow in a self-similar manner and that compound fault systems develop in a stepwise pattern in Dmax/L space.

  4. Basalt: Biologic Analog Science Associated with Lava Terrains (United States)

    Lim, D. S. S.; Abercromby, A.; Kobs-Nawotniak, S. E.; Kobayashi, L.; Hughes, S. S.; Chappell, S.; Bramall, N. E.; Deans, M. C.; Heldmann, J. L.; Downs, M.; Cockell, C. S.; Stevens, A. H.; Caldwell, B.; Hoffman, J.; Vadhavk, N.; Marquez, J.; Miller, M.; Squyres, S. W.; Lees, D. S.; Fong, T.; Cohen, T.; Smith, T.; Lee, G.; Frank, J.; Colaprete, A.


    This presentation will provide an overview of the BASALT (Biologic Analog Science Associated with Lava Terrains) program. BASALT research addresses Science, Science Operations, and Technology. Specifically, BASALT is focused on the investigation of terrestrial volcanic terrains and their habitability as analog environments for early and present-day Mars. Our scientific fieldwork is conducted under simulated Mars mission constraints to evaluate strategically selected concepts of operations (ConOps) and capabilities with respect to their anticipated value for the joint human and robotic exploration of Mars. a) Science: The BASALT science program is focused on understanding habitability conditions of early and present-day Mars in two relevant Mars-analog locations (the Southwest Rift Zone (SWRZ) and the East Rift Zone (ERZ) flows on the Big Island of Hawai'i and the eastern Snake River Plain (ESRP) in Idaho) to characterize and compare the physical and geochemical conditions of life in these environments and to learn how to seek, identify, and characterize life and life-related chemistry in basaltic environments representing these two epochs of martian history. b) Science Operations: The BASALT team will conduct real (non-simulated) biological and geological science at two high-fidelity Mars analogs, all within simulated Mars mission conditions (including communication latencies and bandwidth constraints) that are based on current architectural assumptions for Mars exploration missions. We will identify which human-robotic ConOps and supporting capabilities enable science return and discovery. c) Technology: BASALT will incorporate and evaluate technologies in to our field operations that are directly relevant to conducting the scientific investigations regarding life and life-related chemistry in Mars-analogous terrestrial environments. BASALT technologies include the use of mobile science platforms, extravehicular informatics, display technologies, communication


    Directory of Open Access Journals (Sweden)

    Nanik Suciati


    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Model-model kurva banyak digunakan untuk pembuatan sketsa. Untuk merancang model kurva untuk sketsa tersebut dapat dilakukan dengan berbagai macam cara. Salah satunya adalah menyusun program secara manual dalam membentuk model-model kurva untuk menggambar sketsa yang diinginkan. Pendekatan ini memberi kontrol yang besar ke programmer. Pendekatan lain yaitu mengambil detail kurva yang dimasukkan pengguna. Salah satu metode dalam pendekatan ini adalah dengan mempelajari style-style garis dari contoh - contoh. Pendekatan ini disebut dengan pendekatan curve analogies. Penelitian ini bertujuan untuk menerapkan metode curve analogies dalam membuat editor kurva polyline. Curve Analogies bertujuan membentuk kurva baru dari kurva contoh. Inputan untuk kurva analogies ada 3 macam yaitu dua kurva garis dan satu kurva detil (kurva contoh. Dua kurva garis tersebut adalah kurva inputan dari pengguna dan kurva yang mengikuti kurva detil. Dua kurva garis ini digunakan untuk mencari nilai transformasi. Sedangkan untuk membuat kurva baru dilakukan proses synthesis dengan algoritma synthesis. Algoritma synthesis membentuk kurva baru berdasarkan style dari kurva contoh. Kurva hasil proses synthesis di transformasi sesuai dengan

  6. Analogical acts as conceptual strategies in science, engineering and the humanities (United States)

    Winkler, V. M.


    The composing models which operate by means of analogy are identified. The importance of analogical acts in the prewriting stage of the composing process is discussed. The relations between analogical acts and concept formation are explored. A basic correspondence between the analogical thinking employed in successful learning and analogical thinking as a composing strategy is discussed. Teaching analogical acts as conceptual strategies for exploring problems and generating the form and content of discourse is presented in support of the contention that writing is a unique mode of learning.

  7. Shannon Meets Nyquist: Capacity Limits of Sampled Analog Channels

    CERN Document Server

    Chen, Yuxin; Goldsmith, Andrea J


    We explore two fundamental questions at the intersection of sampling theory and information theory: how is channel capacity affected by sampling below the channel's Nyquist rate, and what sub-Nyquist sampling strategy should be employed to maximize capacity. In particular, we first derive the capacity of sampled analog channels for two prevalent sampling mechanisms: filtering followed by sampling and sampling following filter banks. Connections between sampling and MIMO Gaussian channels are illuminated based on this analysis. Optimal prefilters that maximize capacity are identified for both cases, as well as several kinds of channels for which these sampling mechanisms are optimal to maximize capacity at sub-Nyquist rates. We also highlight connections between sampled analog channel capacity and minimum mean squared error estimation from sampled data. In particular, it is shown that for both filtering and filter-bank sampling strategies, the filters maximizing capacity and minimizing mean squared error are e...

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

    DEFF Research Database (Denmark)

    Franke, Nikolaus; Poetz, Marion; Schreier, Martin


    Who provides better inputs to new product ideation tasks, problem solvers with expertise in the area for which new products are to be developed or problem solvers from “analogous” markets that are distant but share an analogous problem or need? Conventional wisdom appears to suggest that target...... market expertise is indispensable, which is why most managers searching for new ideas tend to stay within their own market context even when they do search outside their firms' boundaries. However, in a unique symmetric experiment that isolates the effect of market origin, we find evidence...... for the opposite: Although solutions provided by problem solvers from analogous markets show lower potential for immediate use, they demonstrate substantially higher levels of novelty. Also, compared to established novelty drivers, this effect appears highly relevant from a managerial perspective: we find...

  9. Use of analogies by novice and experienced design engineers

    DEFF Research Database (Denmark)

    Ahmed, Saeema; Christensen, Bo T.


    This paper describes a study to understand the use of analogies by design engineers with different levels of experience. Protocol analyses of twelve design engineers have been analysed to understand the functions and reasoning of the analogies. The protocols are real world data from the aerospace...... industry. The findings indicate a significant difference in both the functions and reasoning by novices and experienced designers. Novices were found to predominantly transfer information without explicit reference to design issues, whereas experienced designers tended to either solve or identify problems....... Experienced designers were found to reason about the function of a component and to some degree the predicted behaviour of the component, whereas the novices seem to lack such reasoning processes....

  10. Optimal properties of analog perceptrons with excitatory weights.

    Directory of Open Access Journals (Sweden)

    Claudia Clopath

    Full Text Available The cerebellum is a brain structure which has been traditionally devoted to supervised learning. According to this theory, plasticity at the Parallel Fiber (PF to Purkinje Cell (PC synapses is guided by the Climbing fibers (CF, which encode an 'error signal'. Purkinje cells have thus been modeled as perceptrons, learning input/output binary associations. At maximal capacity, a perceptron with excitatory weights expresses a large fraction of zero-weight synapses, in agreement with experimental findings. However, numerous experiments indicate that the firing rate of Purkinje cells varies in an analog, not binary, manner. In this paper, we study the perceptron with analog inputs and outputs. We show that the optimal input has a sparse binary distribution, in good agreement with the burst firing of the Granule cells. In addition, we show that the weight distribution consists of a large fraction of silent synapses, as in previously studied binary perceptron models, and as seen experimentally.

  11. A neurocomputer based on an analog-digital hybrid architecture (United States)

    Moopenn, A.; Thakoor, A. P.; Duong, T.; Khanna, S. K.


    A novel analog-digital hybrid architecture based on the utilization of high density digital random access memories for the storage of the synaptic weights of a neural network, and high speed analog hardware to perform neural computation is described. An electronic neurocomputer based on such an architecture is ideally suited for investigating the dynamics, associative recall properties, and computational capabilities of neural networks and provides significant speed improvement in comparison to conventional software based neural network simulations. As a demonstration of the feasibility of the hybrid architectural concept, a prototype breadboard hybrid neurocomputer system with 32 neurons has been designed and fabricated with off-the-shelf hardware components. The performance of the breadboard system has been tested for variety of applications including associative memory and combinatorial problem solving such as Graph Coloring, and is discussed in this paper.

  12. Analog integrated circuits design for processing physiological signals. (United States)

    Li, Yan; Poon, Carmen C Y; Zhang, Yuan-Ting


    Analog integrated circuits (ICs) designed for processing physiological signals are important building blocks of wearable and implantable medical devices used for health monitoring or restoring lost body functions. Due to the nature of physiological signals and the corresponding application scenarios, the ICs designed for these applications should have low power consumption, low cutoff frequency, and low input-referred noise. In this paper, techniques for designing the analog front-end circuits with these three characteristics will be reviewed, including subthreshold circuits, bulk-driven MOSFETs, floating gate MOSFETs, and log-domain circuits to reduce power consumption; methods for designing fully integrated low cutoff frequency circuits; as well as chopper stabilization (CHS) and other techniques that can be used to achieve a high signal-to-noise performance. Novel applications using these techniques will also be discussed.

  13. Synthesis of tritium-labeled vitamin A and its analogs

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, S.W.; Bubb, J.E.


    Metabolic and pharmacologic studies of Vitamin A and its analogs related to the prevention of lung cancer and other epithelial cancers required tritium-labeled Vitamin A analogs and ..beta..-carotene at high specific activity. Syntheses of some of the isomers were therefore developed in the laboratory, as described in the paper. The advantages of the scheme shown are that : 1. Tritiums are introduced into the molecule by catalytic hydrogenation, thus affording high specific activity. 2. It uses an allylic rearrangement of tritiated vinyl-..beta..-ionol to C/sub 15/-phosphonium salt, which is condensed with C/sub 5/-nitrile to give C/sub 20/-skeleton of retinonitrile. 3. It permits the development of milder methods to convert tritium-labeled retinaldehyde, as a common intermediate, to the other retinoids (i.e., retinoic acid, retinol, and retinyl acetate). Furthermore, tritium-labeled all-trans-..beta..-carotene, an important carotenoid, has been obtained from the retinaldehyde.

  14. Mud Volcanoes of Trinidad as Astrobiological Analogs for Martian Environments

    Directory of Open Access Journals (Sweden)

    Riad Hosein


    Full Text Available Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i Digity; (ii Piparo and (iii Devil’s Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region.

  15. [Role of somatostatin analogs in the treatment of neuroendocrine tumours]. (United States)

    Cuccurullo, V; Cascini, G L; Rambaldi, P F; Mansi, L


    Current therapeutic approaches in neuroendocrine tumours include surgery, radiotherapy and polychemotherapy. Different metabolic patterns of neuroendocrine tumours allow the use of a wide range of diagnostic options in nuclear medicine, due to the presence of a wide spectrum of radiotracers electively concentrating in these neoplasms. Nuclear medicine, and in particular 111In Octreotide (OCT) scintigraphy, 123I Methaiodobenzylguanidine (MIBG) and pentavalent 99mTc-DMSA (V-DMSA), together with biohumoral markers, are currently able to locate tumours also not detectable using traditional diagnostic techniques. Somatostatin analogs, such as octreotide have become increasingly important over the years in the treatment of patients with neuroendocrine tumours. At present the therapeutic use of somatostatin analogs can be schematised as 1) pharmacological treatment (with cold octreotide); 2) surgical treatment (radioguided surgery); 3) radiometabolic treatment (with marked octreotide). The development of new synthetic molecules and new radiocompounds will probably open up interesting scenarios in the near future.

  16. Mud Volcanoes of Trinidad as Astrobiological Analogs for Martian Environments (United States)

    Hosein, Riad; Haque, Shirin; Beckles, Denise M.


    Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC) was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i) Digity; (ii) Piparo and (iii) Devil’s Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region. PMID:25370529

  17. Analog Front-End Electronics in Beam Instrumentation

    CERN Document Server

    Boscolo, A


    The work gives an overview of present and near future technological opportunities for the first analog conditioning and subsequent signal processing of sensor signal. The interactions between beam sensor capability, their signals characteristics and the system requirements are analyzed from different approaches as: full analog continuous, sampled time discrete, full digital time and amplitude discrete. Special attention will be given to the impact of measurement methods and new devices in circuits and instrumentation architecture design, especially from the metrological point of view. A lot of measurement methods and related systems have been developed in order to overcome technological drawbacks and to reach the best cost-performances ratio. By a system revamping, some of these still now show the capability of reaching the actual technological limits in a simpler way in many applications as: ADC, linear and non linear signal processing, ultra high speed logic, etc. These methods could be carried out by the n...

  18. System-level techniques for analog performance enhancement

    CERN Document Server

    Song, Bang-Sup


    This book shows readers to avoid common mistakes in circuit design, and presents classic circuit concepts and design approaches from the transistor to the system levels. The discussion is geared to be accessible and optimized for practical designers who want to learn to create circuits without simulations. Topic by topic, the author guides designers to learn the classic analog design skills by understanding the basic electronics principles correctly, and further prepares them to feel confident in designing high-performance, state-of-the art CMOS analog systems. This book combines and presents all in-depth necessary information to perform various design tasks so that readers can grasp essential material, without reading through the entire book. This top-down approach helps readers to build practical design expertise quickly, starting from their understanding of electronics fundamentals. .

  19. Equivalence-principle Analog of the Gravitational Redshift

    CERN Document Server

    Arms, K


    What happens when two synchronized clocks on a rigid beam are both given the exact same acceleration profile? Will they remain synchronized? What if we use a rigid-rod Rindler acceleration profile? The special relativity prediction surprises many people. This experimental setup is the special-relativity analog of the gravitational redshift. Just like two clocks higher and lower in a gravitational field lose synchronization, one sees a loss of synchronization in these clocks with `identical' acceleration profiles. To the best of our knowledge this equivalence principle analog has never been directly measured, and current experimental techniques are sensitive enough to measure it. We discuss the origin of the essential physics behind this synchronization loss, and some special conditions which simplify its experimental observation. We discuss the origin of the essential physics behind this synchronization loss, and some special conditions which simplify its experimental observation. If validated this effect wil...

  20. 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.

  1. Digitalization and networking of analog simulators and portal images. (United States)

    Pesznyák, Csilla; Zaránd, Pál; Mayer, Arpád


    Many departments have analog simulators and irradiation facilities (especially cobalt units) without electronic portal imaging. Import of the images into the R&V (Record & Verify) system is required. Simulator images are grabbed while portal films scanned by using a laser scanner and both converted into DICOM RT (Digital Imaging and Communications in Medicine Radiotherapy) images. Image intensifier output of a simulator and portal films are converted to DICOM RT images and used in clinical practice. The simulator software was developed in cooperation at the authors' hospital. The digitalization of analog simulators is a valuable updating in clinical use replacing screen-film technique. Film scanning and digitalization permit the electronic archiving of films. Conversion into DICOM RT images is a precondition of importing to the R&V system.

  2. Overcoming nucleoside analog chemoresistance of pancreatic cancer: A therapeutic challenge (United States)

    Hung, Sau Wai; Mody, Hardik R.; Govindarajan, Rajgopal


    Clinical refractoriness to nucleoside analogs (e.g., gemcitabine, capecitabine) is a major scientific problem and is one of the main reasons underlying the extremely poor prognostic state of pancreatic cancer. The drugs’ effects are suboptimal partly due to cellular mechanisms limiting their transport, activation, and overall efficacy. Nonetheless, novel therapeutic approaches are presently under study to circumvent nucleoside analog resistance in pancreatic cancer. With these new approaches come additional challenges to be addressed. This review describes the determinants of chemoresistance in the gemcitabine cytotoxicity pathways, provides an overview of investigational approaches for overcoming chemoresistance, and discusses new challenges presented. Understanding the future directions of the field may assist in the successful development of novel treatment strategies for enhancing chemotherapeutic efficacy in pancreatic cancer. PMID:22425961

  3. Optimizing analog-to-digital converters for sampling extracellular potentials. (United States)

    Artan, N Sertac; Xu, Xiaoxiang; Shi, Wei; Chao, H Jonathan


    In neural implants, an analog-to-digital converter (ADC) provides the delicate interface between the analog signals generated by neurological processes and the digital signal processor that is tasked to interpret these signals for instance for epileptic seizure detection or limb control. In this paper, we propose a low-power ADC architecture for neural implants that process extracellular potentials. The proposed architecture uses the spike detector that is readily available on most of these implants in a closed-loop with an ADC. The spike detector determines whether the current input signal is part of a spike or it is part of noise to adaptively determine the instantaneous sampling rate of the ADC. The proposed architecture can reduce the power consumption of a traditional ADC by 62% when sampling extracellular potentials without any significant impact on spike detection accuracy.

  4. Enhanced X-ray Emission from Early Universe Analog Galaxies (United States)

    Brorby, Matthew; Kaaret, Philip; Prestwich, Andrea H.; Mirabel, I. Felix; Feng, Hua


    X-rays from binaries containing compact objects may have played an important role in heating the early Universe. Here we discuss our findings from X-ray studies of blue compact dwarf galaxies (BCDs), Lyman break analogs (LBAs), and Green Pea galaxies (GP), all of which are considered local analogs to high redshift galaxies. We find enhanced X-ray emission per unit star-formation rate which strongly correlates with decreasing metallicity. We find evidence for the existence of a L_X-SFR-Metallicity plane for star-forming galaxies. The exact properties of X-ray emission in the early Universe affects the timing and morphology of reionization, both being observable properties of current and future radio observations of the redshifted 21cm signal from neutral hydrogen.

  5. Implementing early vision algorithms in analog hardware: an overview (United States)

    Koch, Christof


    In the last ten years, significant progress has been made in understanding the first steps in visual processing. Thus, a large number of algorithms exist that locate edges, compute disparities, estimate motion fields and find discontinuities in depth, motion, color and intensity. However, the application of these algorithms to real-life vision problems has been less successful, mainly because the associated computational cost prevents real-time machine vision implementations on anything but large-scale expensive digital computers. We here review the use of analog, special-purpose vision hardware, integrating image acquisition with early vision algorithms on a single VLSI chip. Such circuits have been designed and successfully tested for edge detection, surface interpolation, computing optical flow and sensor fusion. Thus, it appears that real-time, small, power-lean and robust analog computers are making a limited comeback in the form of highly dedicated, smart vision chips.

  6. 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.

  7. Textual Data in Psychiatry: Reasoning by Analogy to Quantitative Principles


    Yang, Suzanne; Mulvey, Edward P.; Falissard, Bruno


    Personal meaning in subjective experience is a key element in the treatment of persons with mental disorders. Open-response speech samples would appear to be suitable for studying this type of subjective experience, but there are still important challenges in using language as data. Scientific principles involved in sample size calculation, validity, and reliability may be applicable, by analogy, to data collected in the form of words. We describe a rationale for including computer-assisted t...

  8. Frequency to Voltage Converter Analog Front-End Prototype (United States)

    Mata, Carlos; Raines, Matthew


    The frequency to voltage converter analog front end evaluation prototype (F2V AFE) is an evaluation board designed for comparison of different methods of accurately extracting the frequency of a sinusoidal input signal. A configurable input stage is routed to one or several of five separate, configurable filtering circuits, and then to a configurable output stage. Amplifier selection and gain, filter corner frequencies, and comparator hysteresis and voltage reference are all easily configurable through the use of jumpers and potentiometers.

  9. Decision-making and strategic thinking through analogies


    Linhares, Dr Alexandre


    When faced with a complex scenario, how does understanding arise in one’s mind? How does one integrate disparate cues into a global, meaningful whole? Consider the chess game: how do humans avoid the combinatorial explosion? How are abstract ideas represented? The purpose of this paper is to propose a new computational model of human chess intuition and intelligence. We suggest that analogies and abstract roles are crucial to solving these landmark problems. We present a proof-of-concept mo...

  10. 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 over childhood and adolescence (e.g. chalk is to chalkboard as pen is to…?). We hypothesized that age-related differences would manifest as differences in the brain regions associated with one or more of the following cognitive functions: (1) controlled semantic retrieval, or the ability to retrieve task-relevant semantic associations; (2) response control, or the ability to override the tendency to respond to a salient distractor; and/or (3) relational integration, or the ability to consider jointly two mental relations. In order to test these hypotheses, we analyzed patterns of fMRI activation during performance of a pictorial propositional analogy task across 95 typically developing children between the ages of 6 and 18 years old. Despite large age-related differences in task performance, particularly over ages 6-10 but through to around age 14, participants across the whole age range recruited a common network of frontal, parietal and temporal regions. However, activation in a brain region that has been implicated in controlled semantic retrieval - left anterior prefrontal cortex (BA 47/45) - was positively correlated with age, and also with performance after controlling for age. This finding indicates that improved performance over middle childhood and early adolescence on this analogical reasoning task is driven largely by improvements in the ability to selectively retrieve task-relevant semantic relationships. © 2017 The Authors. Developmental Science Published by John Wiley & Sons Ltd.

  11. Terrestrial subaqueous seafloor dunes: Possible analogs for Venus (United States)

    Neakrase, Lynn D. V.; Klose, Martina; Titus, Timothy N.


    Dunes on Venus, first discovered with Magellan Synthetic Aperture Radar (SAR) in the early 1990s, have fueled discussions about the viability of Venusian dunes and aeolian grain transport. Confined to two locations on Venus, the existence of the interpreted dunes provides evidence that there could be transportable material being mobilized into aeolian bedforms at the surface. However, because of the high-pressure high-temperature surface conditions, laboratory analog studies are difficult to conduct and results are difficult to extrapolate to full-sized, aeolian bedforms. Field sites of desert dunes, which are well-studied on Earth and Mars, are not analogous to what is observed on Venus because of the differences in the fluid environments. One potentially underexplored possibility in planetary science for Venus-analog dune fields could be subaqueous, seafloor dune fields on Earth. Known to the marine geology communities since the early 1960s, seafloor dunes are rarely cited in planetary aeolian bedform literature, but could provide a necessary thick-atmosphere extension to the classically studied aeolian dune environment literature for thinner atmospheres. Through discussion of the similarity of the two environments, and examples of dunes and ripples cited in marine literature, we provide evidence that subaqueous seafloor dunes could serve as analogs for dunes on Venus. Furthermore, the evidence presented here demonstrates the usefulness of the marine literature for thick-atmosphere planetary environments and potentially for upcoming habitable worlds and oceanic environment research program opportunities. Such useful cross-disciplinary discussion of dune environments is applicable to many planetary environments (Earth, Mars, Venus, Titan, etc.) and potential future missions.

  12. Activity and Export of Engineered Nisin-(1-22) Analogs


    Plat, Annechien; Kuipers, Anneke; Lange, Jacobien G. de; Moll, Gert N.; Rink, Rick


    The pentacyclic peptide antibiotic nisin, produced by Lactococcus lactis is ubiquitously applied as a food preservative. We previously demonstrated that the truncated nisin-(1-22) has only 10-fold lower activity than nisin. Here we aimed at further developing this tricyclic nisin analog to reach activity comparable to that of nisin. Our data demonstrate that: (1) ring A has a large mutational freedom; (2) the composition of residues 20–22 strongly affects production levels of nisin-(1-22); (3...

  13. In vitro evaluation of nicotinamide riboside analogs against Haemophilus influenzae.


    Godek, C P; Cynamon, M H


    Exogenous NAD, nicotinamide mononucleotide, or nicotinamide riboside is required for the growth of Haemophilus influenzae. These compounds have been defined as the V-factor growth requirement. We have previously shown that the internalization of nicotinamide riboside is energy dependent and carrier mediated with saturation kinetics. Thionicotinamide riboside, 3-pyridinealdehyde riboside, 3-acetylpyridine riboside, and 3-aminopyridine riboside were prepared from their corresponding NAD analogs...

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

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, W.M. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)


    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.

  15. Synthesis of Analog and Digital Filters in LabVIEW

    Directory of Open Access Journals (Sweden)

    Zhanna K. Satbayeva


    Full Text Available The paper introduces the method of analog and digital filters designing. The direct approach to the designing of the approximating polynomial for Bessel low-pass with maximum flat group delay was used. The scheme of Bessel low-pass was implemented for the specified transfer function. The automated system for time, frequency and dynamic filter characteristics measurement was designed in graphic programming environment of LabVIEW 10

  16. Using Cortically-Inspired Algorithms for Analogical Learning and Reasoning (United States)


    Related work on representing structure as features There has been some work on representing structures as vectors. For example, Holographic Reduced ...analogy to problems of surface similarity. Some of these problems and their reduced versions are shown in Fig. 10. Our representation also offers a new...used to process relational structures. We present a system that represents relational structures as fea- ture bags. Using this representation , our

  17. Spontaneous Analogy by Piggybacking on a Perceptual System (United States)


    has been some work on representing structures as feature vectors. For example, Holographic Reduced Repre- sentations have been used to implement Vector...analogy. We present a system that represents relational structures as feature bags. Us- ing this representation , our system leverages perceptual algo...regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington

  18. 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.

  19. Terrestrial subaqueous seafloor dunes: Possible analogs for Venus (United States)

    Neakrase, Lynn D.V.; Klose, Martina; Titus, Timothy N.


    Dunes on Venus, first discovered with Magellan Synthetic Aperture Radar (SAR) in the early 1990s, have fueled discussions about the viability of Venusian dunes and aeolian grain transport. Confined to two locations on Venus, the existence of the interpreted dunes provides evidence that there could be transportable material being mobilized into aeolian bedforms at the surface. However, because of the high-pressure high-temperature surface conditions, laboratory analog studies are difficult to conduct and results are difficult to extrapolate to full-sized, aeolian bedforms. Field sites of desert dunes, which are well-studied on Earth and Mars, are not analogous to what is observed on Venus because of the differences in the fluid environments. One potentially underexplored possibility in planetary science for Venus-analog dune fields could be subaqueous, seafloor dune fields on Earth. Known to the marine geology communities since the early 1960s, seafloor dunes are rarely cited in planetary aeolian bedform literature, but could provide a necessary thick-atmosphere extension to the classically studied aeolian dune environment literature for thinner atmospheres. Through discussion of the similarity of the two environments, and examples of dunes and ripples cited in marine literature, we provide evidence that subaqueous seafloor dunes could serve as analogs for dunes on Venus. Furthermore, the evidence presented here demonstrates the usefulness of the marine literature for thick-atmosphere planetary environments and potentially for upcoming habitable worlds and oceanic environment research program opportunities. Such useful cross-disciplinary discussion of dune environments is applicable to many planetary environments (Earth, Mars, Venus, Titan, etc.) and potential future missions.

  20. Carboxy Methyl and Carboxy Analogs Argaminolics B and C

    Directory of Open Access Journals (Sweden)

    Karel D. Klika


    Full Text Available Two new analogs, a carboxy methyl (Argaminolic B and a carboxy derivative (Argaminolic C, of a recently reported amino phenolic, Argaminolic A, isolated from the fruit of the argan tree, Argania spinosa (Skeels L., are described. Argaminolic B exhibits facile hydrolysis of its methyl ester to yield Argaminolic C, which then undergoes a remarkably facile decarboxylation to the previously described Argaminolic A.

  1. Substrate noise coupling in analog/RF circuits

    CERN Document Server

    Bronckers, Stephane; Vandersteen, Gerd; Rolain, Yves


    This practical resource offers you detailed guidance on the impact of substrate noise on a wide range of circuits operating from baseband frequencies up to mm-wave frequencies. This unique book presents case studies to illustrate that careful modeling of the assembly characteristics and layout details is required to bring simulations and measurements into agreement. You learn how to use a proper combination of isolation structures and circuit techniques to make analog/RF circuits more immune to substrate noise.

  2. Latchup in CMOS analog-to-digital converters (United States)

    Miyahira, T.; Johnston, A.


    Heavy-ion latchup is investigated for analog-to-digital converters. Differences in cross section for various ions shows that charge is collected at depths beyond 50 um, causing the cross section to be underestimated unless long-range ions are used. Current distributions and thermal imaging were used to identify latchup-sensitive regions. Latchup in one of the circuittypes was catastrophic, even when the power was turned off within 10 ms of a latchup event.

  3. New technologies for radiation-hardening analog to digital converters (United States)

    Gauthier, M. K.


    Surveys of available Analog to Digital Converters (ADC) suitable for precision applications showed that none have the proper combination of accuracy and radiation hardness to meet space and/or strategic weapon requirements. A development program which will result in an ADC device which will serve a number of space and strategic applications. Emphasis was placed on approaches that could be integrated onto a single chip within three to five years.

  4. Perancangan Switch Matrik Besar Menggunakan Array Switch Analog Zarlink


    M. Zulfin


    Secara tradisional, perancangan sebuah switch matrik yang besar dilakukan dengan menggunakan switch-switch elektromekanik. Dengan demikian, banyak bagian yang bergerak yang digunakan untuk membangun switch matrik ini. Dengan kemajuan bidang elektronik, switch elektromekanik saat ini dapat digantikan dengan switch-switch semikonduktor yang ekivalen yang menawarkan solusi yang lebih ekonomis dan memiliki keandalan yang lebih baik. Rumpun switch crosspoint analog Zarlink dapat disusun dengan mud...

  5. Discursive interactions and the use of analogies in physics teaching

    Directory of Open Access Journals (Sweden)

    Fernanda Cátia Bozelli


    Full Text Available In the last few years, Science Education researchers have shown new ways do conceive the processes of teaching and learning, demanding the displacement from the individual understanding of specific phenomena to a new context, which means, to a bias of meanings construction in a social context. However, still there are few researches concerned with how teachers give support to the process throughout the students build meanings in science classrooms, about how these interactions are produced, developed and, in what level they indeed interfere in students’ learning. This research tries to move forward in this line of research, investigating the interactive discursive processes related to the figures of speech (in this case, analogies, particularly about the context of its creation, working out and exploration in physics classrooms. One of the questions which allowed that reflection was that to explain scientific concepts in classroom involves, even to understand contents, as to be able to communicate this content in a more effective way. Does the posture assumed by teachers in the conversational aspect, during the discursive interaction, has contributed or influenced the rise and exploration of analogies in classrooms? To answer these questions we adopted a qualitative and interpretative approach, trough which we analyzed a sample of 23 futures high school physics teachers, during a semester, when the development of supervised practicum activities, carried out in the two last semesters of their undergraduate program, done in a public state university in São Paulo, Brazil. Data collected show that it is necessary more discussion about the use of analogies in teachers initial training programs; taking account its function, benefit or disadvantage, how to explore analogies in a more effective way. Besides that, how the discursive interactive context among teacher and students can interfere in the teaching and learning processes in classroom. We

  6. Structural Perspectives of Insulin Receptor Isoform-Selective Insulin Analogs

    Czech Academy of Sciences Publication Activity Database

    Jiráček, Jiří; Žáková, Lenka


    Roč. 8, Jul 27 (2017), č. článku 167. ISSN 1664-2392 R&D Projects: GA ČR GA15-19018S Institutional support: RVO:61388963 Keywords : insulin receptor * insulin binding * analog * diabetes * glucose Subject RIV: CE - Biochemistry Impact factor: 3.675, year: 2016 http:// journal

  7. Synthesis and biological evaluation of biaryl analogs of antitubulin compounds

    Energy Technology Data Exchange (ETDEWEB)

    Tozatti, Camila Santos Suniga; Khodyuk, Rejane Goncalves Diniz; Silva, Adriano Olimpio da; Santos, Edson dos Anjos dos; Amaral, Marcos Serrou do; Lima, Denis Pires de, E-mail: [Centro de Ciencias Exatas e Tecnologia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil); Hamel, Ernest [Screening Technologies Branch, Division of Cancer Treatment and Diagnosis, National Cancer Institute at Frederick, MD (United States)


    This paper reports the synthesis of methanones and esters bearing different substitution patterns as spacer groups between aromatic rings. This series of compounds can be considered phenstatin analogs. Two of the newly synthesized compounds, 5a and 5c, strongly inhibited tubulin polymerization and the binding of [{sup 3}H] colchicine to tubulin, suggesting that, akin to phenstatin and combretastatin A-4, they can bind to tubulin at the colchicine site. (author)

  8. Synthesis and biological evaluation of biaryl analogs of antitubulin compounds

    Directory of Open Access Journals (Sweden)

    Camila Santos Suniga Tozatti


    Full Text Available This paper reports the synthesis of methanones and esters bearing different substitution patterns as spacer groups between aromatic rings. This series of compounds can be considered phenstatin analogs. Two of the newly synthesized compounds, 5a and 5c, strongly inhibited tubulin polymerization and the binding of [³H] colchicine to tubulin, suggesting that, akin to phenstatin and combretastatin A-4, they can bind to tubulin at the colchicine site.

  9. Uncertainties analysis made easy using basic electricity analogy

    CERN Document Server

    Cardoso, George C


    This paper proposes a battery-resistor circuit to aid introductory laboratory students visualize concepts of experimental measurement uncertainty, sums of uncertainties and uncertainty of the mean value. In the model presented the uncertainty or noise can be though of as noise in a loudspeaker, making the analogy simple to understand. The mathematics used is simple, requires no knowledge of statistics and provides correct expressions.

  10. Speckle imaging with the PAPA detector. [Precision Analog Photon Address (United States)

    Papaliolios, C.; Nisenson, P.; Ebstein, S.


    A new 2-D photon-counting camera, the PAPA (precision analog photon address) detector has been built, tested, and used successfully for the acquisition of speckle imaging data. The camera has 512 x 512 pixels and operates at count rates of at least 200,000/sec. In this paper, technical details on the camera are presented and some of the laboratory and astronomical results are included which demonstrate the detector's capabilities.

  11. 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.

  12. Synthesis of a Novel Carbocyclic Analog of Bredinin

    Directory of Open Access Journals (Sweden)

    Vasu Nair


    Full Text Available The natural nucleoside antibiotic, bredinin, exhibits antiviral and other biological activities. While various nucleosides related to bredinin have been synthesized, its carbocyclic analog has remained unknown. Synthesis of this heretofore unknown analog of bredinin is described. The key precursor, (3aS,4R,6R,6aR-6-((methoxy-methoxymethyl-2,2-dimethyltetrahydro-3aH-cyclopenta[d][1,3]dioxol-4-amine (5, was prepared from the commercially available compound, (1R,4S-2-azabicyclo[2.2.1] hept-5-en-3-one (4. Our initial approach used intermediate 6, derived in three transformations from 5, for the key photolytic step to produce the desired ring-opened precursor to the target compound. This photochemical transformation was unsuccessful. However, an appropriately protected and related precursor was synthesized from 5 through the following side-chain functional group transformations: elaboration of the amino group through malonyl ester formation, oximation at the central carbon, conversion of ester to amide and catalytic reduction of the oxime group. This precursor, on treatment with triethylorthoformate and catalytic acetic acid in ethanol, underwent cyclization to produce the desired 4-carbamoyl-imidazolium-5-olate ring. Deprotection of the latter product proceeded smoothly to give the carbocyclic analog of bredinin. This target molecule exhibits antiviral activity, albeit low, against a number of RNA viruses. Further biological evaluations are in progress.

  13. Limits of Religious Analogy: The Example of Celebrity

    Directory of Open Access Journals (Sweden)

    Nathalie Heinich


    Full Text Available Focusing on celebrities is often compared to a religious behavior, be it by the actors when describing their own practices or by scholars when using analogies with “cult”, “sacralization” or “sanctification”. Such comparisons appear to be both obvious and hardly convincing, since they merely evoke, without analyzing or explaining. Moreover, they ignore the normative effects—be they positive or negative—produced by any kind of religious analogy. This paper proposes several paths toward a reasoned use of comparison with religion: extending comparison to differences and not only to resemblances; passing from “religion” in general to the plurality of religions; deconstructing the said “religious” phenomenon into several functions depending on contexts; replacing discontinuous categories by continuous typologies and, finally, “religion” conceived as an original matrix by “religion” conceived as a contextual configuration. “Religion” thus appears as a common sense notion rather than as a conceptual instrument, and analysis may then fully develop without being restricted by religious analogies, while comparison may be used as a real tool.


    Directory of Open Access Journals (Sweden)

    Md. Abdul Hye Khan


    Full Text Available Epoxyeicosatrienoic acids (EETs contribute to blood pressure regulation leading to the concept that EETs can be therapeutically targeted for hypertension and the associated end-organ damage. In the present study, we investigated anti-hypertensive and kidney protective actions of an EET analog, EET-B in angiotensin II (ANG II-induced hypertension. EET-B was administered in drinking water for 14 days (10mg/kg/d and resulted in a decreased blood pressure elevation in ANG II hypertension. At the end of the two-week period, blood pressure was 30 mmHg lower in EET analog-treated ANG II hypertensive rats. The vasodilation of mesenteric resistance arteries to acetylcholine was impaired in ANG II hypertension; however, it was improved with EET-B treatment. Further, EET-B protected the kidney in ANG II hypertension as evidenced by a marked 90% decrease in albuminuria and 54% decrease in nephrinuria. Kidney histology demonstrated a decrease in renal tubular cast formation in EET analog-treated hypertensive rats. In ANG II hypertension, EET-B treatment markedly lowered renal inflammation. Urinary monocyte chemoattractant protein-1 excretion was decreased by 55% and kidney macrophage infiltration was reduced by 52% with EET-B treatment. Overall, our results demonstrate that EET-B has anti-hypertensive properties, improves vascular function, and decreases renal inflammation and injury in ANG II hypertension.

  15. 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.

  16. Ultra-low-energy analog straintronics using multiferroic composites (United States)

    Roy, Kuntal


    Multiferroic devices, i.e., a magnetostrictive nanomagnet strain-coupled with a piezoelectric layer, are promising as binary switches for ultra-low-energy digital computing in beyond Moore's law era [Roy, K. Appl. Phys. Lett. 103, 173110 (2013), Roy, K. et al. Appl. Phys. Lett. 99, 063108 (2011), Phys. Rev. B 83, 224412 (2011), Scientific Reports (Nature Publishing Group) 3, 3038 (2013), J. Appl. Phys. 112, 023914 (2012)]. We show here that such multiferroic devices, apart from performing digital computation, can be also utilized for analog computing purposes, e.g., voltage amplification, filter etc. The analog computing capability is conceived by considering that magnetization's mean orientation shifts gradually although nanomagnet's potential minima changes abruptly. Using tunneling magnetoresistance (TMR) measurement, a continuous output voltage while varying the input voltage can be produced. Stochastic Landau-Lifshitz-Gilbert (LLG) equation in the presence of room-temperature (300 K) thermal fluctuations is solved to demonstrate the analog computing capability of such multiferroic devices. This work was supported in part by FAME, one of six centers of STARnet, a Semiconductor Research Corporation program sponsored by MARCO and DARPA.

  17. Discovery of a Jupiter/Saturn analog with gravitational microlensing. (United States)

    Gaudi, B S; Bennett, D P; Udalski, A; Gould, A; Christie, G W; Maoz, D; Dong, S; McCormick, J; Szymanski, M K; Tristram, P J; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; Depoy, D L; Han, C; Kaspi, S; Lee, C-U; Mallia, F; Natusch, T; Pogge, R W; Park, B-G; Abe, F; Bond, I A; Botzler, C S; Fukui, A; Hearnshaw, J B; Itow, Y; Kamiya, K; Korpela, A V; Kilmartin, P M; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N J; Sako, T; Saito, To; Sato, S; Skuljan, L; Sullivan, D J; Sumi, T; Sweatman, W L; Yock, P C M; Albrow, M D; Allan, A; Beaulieu, J-P; Burgdorf, M J; Cook, K H; Coutures, C; Dominik, M; Dieters, S; Fouqué, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B


    Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of approximately 0.71 and approximately 0.27 times the mass of Jupiter and orbital separations of approximately 2.3 and approximately 4.6 astronomical units orbiting a primary star of mass approximately 0.50 solar mass at a distance of approximately 1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.

  18. Transparency in risk communication: graphical and analog tools. (United States)

    Kurz-Milcke, Elke; Gigerenzer, Gerd; Martignon, Laura


    Why is it that the public can read and write but only a few understand statistical information? Why are elementary distinctions, such as that between absolute and relative risks, not better known? In the absence of statistical literacy, key democratic ideals, such as informed consent and shared decision making in health care, will remain science fiction. In this chapter, we deal with tools for transparency in risk communication. The focus is on graphical and analog representations of risk. Analog representations use a separate icon or sign for each individual in a population. Like numerical representations, some graphical forms are transparent, whereas others indiscernibly mislead the reader. We review cases of (1) tree diagrams for representing natural versus relative frequency, (2) decision trees for the representation of fast and frugal decision making, (3) bar graphs for representing absolute versus relative risk, (4) population diagrams for the analog representation of risk, and (5) a format of representation that employs colored tinker cubes for the encoding of information about individuals in a population. Graphs have long enjoyed the status of being "worth a thousand words" and hence of being more readily accessible to human understanding than long-winded symbolic representations. This is both true and false. Graphical tools can be just as well employed for transparent and nontransparent risk communications.

  19. A high performance SAR ADC for WLAN analog front end (United States)

    Lian, Pengfei; Yi, Bo; Wu, Bin; Wang, Han; Pu, Yilin


    A 10 bit 100 MS/s successive approximation register (SAR) analog to digital converter (ADC) for WLAN analog front end is presented. To ensure high performance and low power, we presented a method that is based on figure of merit (FOM) to obtain the optimal unit capacitance of the digital-to-analog converter (DAC) capacitor network. With this method, we obtain the minimum FOM 17.92 fJ/Conv.-step as well as the optimal unit capacitance of the DAC capacitor network 1.59 fF. What is more, to ensure high performance of the dynamic comparator, a comparator clock logic is presented. Post-simulation results in 55 nm CMOS technology show that, this 10-bit 100-MS/s ADC achieves the signal-to-noise-and-distortion ratio (SNDR), the signal-to-noise ratio (SNR) and the spurious-free dynamic range (SFDR) of 61.7 dB, 63.7 dB and 72.5 dB with 1.3V supply. The ADC consumes 1.67 mW, and the active area is only 0.0162 mm2.

  20. 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.

  1. Thermodynamic analogies in economics and finance: instability of markets (United States)

    McCauley, Joseph L.


    Interest in thermodynamic analogies in economics is older than the idea of von Neumann to look for market entropy in liquidity, advice that was not taken in any thermodynamic analogy presented so far in the literature. In this paper, we go further and use a standard strategy from trading theory to pinpoint why thermodynamic analogies necessarily fail to describe financial markets, in spite of the presence of liquidity as the underlying basis for market entropy. Market liquidity of frequently traded assets does play the role of the ‘heat bath‘, as anticipated by von Neumann, but we are able to identify the no-arbitrage condition geometrically as an assumption of translational and rotational invariance rather than (as finance theorists would claim) an equilibrium condition. We then use the empirical market distribution to introduce an asset's entropy and discuss the underlying reason why real financial markets cannot behave thermodynamically: financial markets are unstable, they do not approach statistical equilibrium, nor are there any available topological invariants on which to base a purely formal statistical mechanics. After discussing financial markets, we finally generalize our result by proposing that the idea of Adam Smith's Invisible Hand is a falsifiable proposition: we suggest how to test nonfinancial markets empirically for the stabilizing action of The Invisible Hand.

  2. Visual relations children find easy and difficult to process in figural analogies

    NARCIS (Netherlands)

    Stevenson, C.E.; Alberto, R.A.; van den Boom, M.A.; de Boeck, P.A.L.


    Analogical reasoning, the ability to learn about novel phenomena by relating it to structurally similar knowledge, develops with great variability in children. Furthermore, the development of analogical reasoning coincides with greater working memory efficiency and increasing knowledge of the

  3. Analogies in physics textbooks for the final grade of primary school

    National Research Council Canada - National Science Library

    Pavlović Zlatko


    ... that describes the way the analogies function. The second part of the paper presents the results of the analysis of the use of analogies in eighth-grade physics textbooks that are used in primary schools in Serbia...

  4. Studies towards the synthesis of ATP analogs as potential glutamine synthetase inhibitors

    CSIR Research Space (South Africa)

    Salisu, S


    Full Text Available In research directed at the development of adenine triphosphate (ATP) analogs as potential glutamine synthetase (GS) inhibitors, adenine and allopurinol derivatives have been synthesized either as novel ATP analogs or as scaffolds...

  5. 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

  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. Social Analogical Reasoning in School-Aged Children with Autism Spectrum Disorder and Typically Developing Peers (United States)

    Green, Adam E.; Kenworthy, Lauren; Gallagher, Natalie M.; Antezana, Ligia; Mosner, Maya G.; Krieg, Samantha; Dudley, Katherina; Ratto, Allison; Yerys, Benjamin E.


    Analogical reasoning is an important mechanism for social cognition in typically developing children, and recent evidence suggests that some forms of analogical reasoning may be preserved in autism spectrum disorder. An unanswered question is whether children with autism spectrum disorder can apply analogical reasoning to social information. In…

  8. Analogical Scaffolding and the Learning of Abstract Ideas in Physics: An Example from Electromagnetic Waves (United States)

    Podolefsky, Noah S.; Finkelstein, Noah D.


    This paper describes a model of analogy, analogical scaffolding, which explains present and prior results of student learning with analogies. We build on prior models of representation, blending, and layering of ideas. Extending this model's explanatory power, we propose ways in which the model can be applied to design a curriculum directed at…

  9. Polyunsaturated fatty acid analogs act antiarrhythmically on the cardiac IKs channel

    DEFF Research Database (Denmark)

    Liin, Sara I.; Silverå Ejneby, Malin; Barro-Soria, Rene


    charge at neutral pH, restore the sensitivity to open IKs channels. PUFA analogs with a positively charged head group inhibit IKs channels. These different PUFA analogs could be developed into drugs to treat cardiac arrhythmias. In support of this possibility, we show that PUFA analogs act...... antiarrhythmically in embryonic rat cardiomyocytes and in isolated perfused hearts from guinea pig....

  10. Analogies as Creative Inspiration Sources in the Design Studio : The Teamwork

    NARCIS (Netherlands)

    Casakin, H.; Van Timmeren, A.


    Analogical reasoning can be seen as an important aid in problem solving, and architectural design problem solving in particular. Analogical reasoning was found to be an important aid supporting architectural education. In this paper we explored the use of visual and verbal analogies in the early

  11. 47 CFR 25.211 - Analog video transmissions in the Fixed-Satellite Services. (United States)


    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Analog video transmissions in the Fixed...) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.211 Analog video transmissions in the Fixed-Satellite Services. (a) Downlink analog video transmissions in the band 3700-4200 MHz...

  12. A Systematic Evaluation of Analogs for the Read-across Prediction of Estrogenicity (Future Tox III) (United States)

    Read-across is a data gap filling technique which is commonly used within category and analog approaches to predict a biological property for a target data-poor chemical using known information from similar (analog) chemical(s). Analog identification and evaluation are critical ...

  13. 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...

  14. A Systematic Evaluation of Analogs and Automated Read-across Prediction of Estrogenicity (QSAR2016) (United States)

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

  15. Concept Confusion and Concept Discernment in Basic Magnetism Using Analogical Reasoning (United States)

    Lemmer, Miriam; Morabe, Olebogeng Nicodimus


    Analogical reasoning is central to all learning, whether in daily life situations, in the classroom or while doing research. Although analogies can aid the learning process of making sense of phenomena and understanding new ideas in terms of known ideas, these should be used with care. This article reports a study of the use of analogies and the…

  16. 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

  17. Quantifying Uncertainty of Wind Power Production Through an Analog Ensemble (United States)

    Shahriari, M.; Cervone, G.


    The Analog Ensemble (AnEn) method is used to generate probabilistic weather forecasts that quantify the uncertainty in power estimates at hypothetical wind farm locations. The data are from the NREL Eastern Wind Dataset that includes more than 1,300 modeled wind farms. The AnEn model uses a two-dimensional grid to estimate the probability distribution of wind speed (the predictand) given the values of predictor variables such as temperature, pressure, geopotential height, U-component and V-component of wind. The meteorological data is taken from the NCEP GFS which is available on a 0.25 degree grid resolution. The methodology first divides the data into two classes: training period and verification period. The AnEn selects a point in the verification period and searches for the best matching estimates (analogs) in the training period. The predictand value at those analogs are the ensemble prediction for the point in the verification period. The model provides a grid of wind speed values and the uncertainty (probability index) associated with each estimate. Each wind farm is associated with a probability index which quantifies the degree of difficulty to estimate wind power. Further, the uncertainty in estimation is related to other factors such as topography, land cover and wind resources. This is achieved by using a GIS system to compute the correlation between the probability index and geographical characteristics. This study has significant applications for investors in renewable energy sector especially wind farm developers. Lower level of uncertainty facilitates the process of submitting bids into day ahead and real time electricity markets. Thus, building wind farms in regions with lower levels of uncertainty will reduce the real-time operational risks and create a hedge against volatile real-time prices. Further, the links between wind estimate uncertainty and factors such as topography and wind resources, provide wind farm developers with valuable

  18. 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).

  19. Deficits in analogical reasoning in adolescents with traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Daniel C Krawczyk


    Full Text Available Individuals with traumatic brain injury (TBI exhibit deficits in executive control, which may impact their reasoning abilities. Analogical reasoning requires working memory and inhibitory abilities. In this study, we tested adolescents with moderate to severe TBI and typically-developing (TD controls on a set of picture analogy problems. Three factors were varied: complexity (number of relations in the problems, distraction (distractor item present or absent, and animacy (living or non-living items in the problems. We found that TD adolescents performed significantly better overall than TBI adolescents. There was also an age effect present in the TBI group where older participants performed better than younger ones. This age effect was not observed in the TD group. Performance was affected by complexity and distraction. Further, TBI participants exhibited lower performance with distractors present than TD participants. The reasoning deficits exhibited by the TBI participants were correlated with measures of executive function that required working memory updating, attention, and attentional screening. Using MRI-derived measures of cortical thickness, correlations were carried out between task accuracy and cortical thickness. The TD adolescents showed negative correlations between thickness and task accuracy in frontal and temporal regions consistent with cortical maturation in these regions. This study demonstrates that adolescent TBI results in impairments in analogical reasoning ability. Further, TBI youth have difficulty effectively screening out distraction, which may lead to failures in comprehension of the relations among items in visual scenes. Lastly, TBI youth fail to show robust cortical-behavior correlations as observed in TD individuals.

  20. Light scattering by planetary-regolith analog samples: computational results (United States)

    Väisänen, Timo; Markkanen, Johannes; Hadamcik, Edith; Levasseur-Regourd, Anny-Chantal; Lasue, Jeremie; Blum, Jürgen; Penttilä, Antti; Muinonen, Karri


    We compute light scattering by a planetary-regolith analog surface. The corresponding experimental work is from Hadamcik et al. [1] with the PROGRA2-surf [2] device measuring the polarization of dust particles. The analog samples are low density (volume fraction 0.15 ± 0.03) agglomerates produced by random ballistic deposition of almost equisized silica spheres (refractive index n=1.5 and diameter 1.45 ± 0.06 µm). Computations are carried out with the recently developed codes entitled Radiative Transfer with Reciprocal Transactions (R2T2) and Radiative Transfer Coherent Backscattering with incoherent interactions (RT-CB-ic). Both codes incorporate the so-called incoherent treatment which enhances the applicability of the radiative transfer as shown by Muinonen et al. [3]. As a preliminary result, we have computed scattering from a large spherical medium with the RT-CB-ic using equal-sized particles with diameters of 1.45 microns. The preliminary results have shown that the qualitative characteristics are similar for the computed and measured intensity and polarization curves but that there are still deviations between the characteristics. We plan to remove the deviations by incorporating a size distribution of particles (1.45 ± 0.02 microns) and detailed information about the volume density profile within the analog surface. Acknowledgments: We acknowledge the ERC Advanced Grant no. 320773 entitled Scattering and Absorption of Electromagnetic Waves in Particulate Media (SAEMPL). Computational resources were provided by CSC - IT Centre for Science Ltd, Finland. References: [1] Hadamcik E. et al. (2007), JQSRT, 106, 74-89 [2] Levasseur-Regourd A.C. et al. (2015), Polarimetry of stars and planetary systems, CUP, 61-80 [3] Muinonen K. et al. (2016), extended abstract for EMTS.

  1. Nicotine analog inhibition of nicotine self-administration in rats. (United States)

    Rowland, Neil E; Robertson, Kimberly; Soti, Ferenc; Kem, William R


    Partial agonists and antagonists of addictive drugs have been useful in the treatment of dependence. The purpose of this study is to determine whether nicotine analogs with partial agonist or antagonist properties at alpha4beta2 nicotinic acetylcholine receptors (nAChRs) inhibit self-administration of nicotine in rats. Male Sprague-Dawley rats were trained to self-administer nicotine (unit dose 0.017 mg/kg) intravenously contingent upon the completion of five lever presses. Once stable responding was established, rats were administered test agents, either as a subcutaneous injection before the daily session or co-infused with nicotine. The number of nicotine injections taken per session was reduced to approximately 50% of baseline after either pre-treatment with the broad spectrum nicotinic receptor antagonist, mecamylamine, or by substituting saline for nicotine (extinction). 4'-Trans-methyl-nicotine, a strong partial agonist, inhibited nicotine self-administration and substituted for nicotine to support self-administration. Partial agonists, prepared by substitution at the 1'-N-position with either ethyl or cyclopropylmethyl moieties, potently inhibited self-administration. Antagonists formed by 5'-methyl substitution also inhibited self-administration, with the 5'-trans-methyl enantiomer about ten times more potent than the 5'-cis-methyl enantiomer. In contrast, antagonists formed by aryl substitution at the 5 position of the pyridyl ring of nicotine did not inhibit self-administration. Intravenous co-infusions had similar effects to the pre-injections. In most instances, doses of the analogs that reduced nicotine self-administration had no effect on food intake when measured using a similar FR5 protocol. Nicotine analogs with alpha4beta2 nAChR partial agonist and antagonist efficacies can inhibit self-administration and may be considered as prototypical smoking-cessation agents.

  2. Introduction to engineering a starter's guide with hands-on analog multimedia explorations

    CERN Document Server

    Karam, Lina


    This lecture provides a hands-on glimpse of the field of electrical engineering. The introduced applications utilize the NI ELVIS hardware and software platform to explore concepts such as circuits, power, analog sensing, and introductory analog signal processing such as signal generation, analog filtering, and audio and music processing. These principals and technologies are introduced in a very practical way and are fundamental to many of the electronic devices we use today. Some examples include photodetection, analog signal (audio, light, temperature) level meter, and analog music equalize

  3. a New Laboratory for Terahertz Characterization of Cosmic Analog Dusts (United States)

    Perera, Thushara


    Two efforts have been underway to enable the laboratory study of cosmic analogs dusts in the frequency range 60--2000 GHz. They are: (1) the construction of a novel compact Fourier Transform Spectrometer (FTS) design coupled to a dry 4-K cryostat which houses a cooled sample exchanger (filter wheel) and a bolometer. (2) The production of Mg- and Fe-rich silicate dusts using sol-gel methods; various tests to determine their physical and chemical properties; embedding of samples in LDPE pellets for insertion into the novel FTS. This presentation will focus on the current status of the apparatus and data from its first few months of use.

  4. Analysis and application of analog electronic circuits to biomedical instrumentation

    CERN Document Server

    Northrop, Robert B


    This book introduces the basic mathematical tools used to describe noise and its propagation through linear systems and provides a basic description of the improvement of signal-to-noise ratio by signal averaging and linear filtering. The text also demonstrates how op amps are the keystone of modern analog signal conditioning systems design, and illustrates their use in isolation and instrumentation amplifiers, active filters, and numerous biomedical instrumentation systems and subsystems. It examines the properties of the ideal op amp and applies this model to the analysis of various circuits

  5. Dynamic mesh optimization based on the spring analogy

    Directory of Open Access Journals (Sweden)

    Schmidt Jonas


    Full Text Available We present an implementation of the spring analogy for three dimensional meshes in OpenFOAM. All parameters of the spring system are treated as fields that can either be pre-defined by the user, or updated at each time step according to specified geometrical regions or diffusion equations. The purpose of the method is to provide a pre-processing tool for mesh optimization. We study three simple test cases, a deformed block, an airfoil and a hill, and we analyze the evolution of skewness, non-orthogonality and aspect ratio during the approach of dynamic equilibrium.

  6. Analog measurement of the autocorrelation function of Gaussian noise (United States)

    Gabriel, C. J.


    A new method for measuring the autocorrelation function of stationary, Gaussian distributed, differentiable or nondifferentiable noise is presented. This method does not require real-time digitizing or analog multiplying and can be easily realized since it is based on the use of either a sampling oscilloscope or a boxcar averager. The method requires the measurement of the ensemble average of the multiple traces generated by internally triggering the oscilloscope or averager on the noise. Expressions for interpreting this average to obtain the autocorrelation function as well as examples of measurements made by this technique are given and discussed.

  7. Sequences of gluing bifurcations in an analog electronic circuit

    Energy Technology Data Exchange (ETDEWEB)

    Akhtanov, Sayat N.; Zhanabaev, Zeinulla Zh. [Physico-Technical Department, Al Farabi Kazakh National University, Al Farabi Av. 71, Almaty, 050038 Kazakhstan (Kazakhstan); Zaks, Michael A., E-mail: [Institute of Mathematics, Humboldt University, Rudower Chaussee 25, D-12489 Berlin (Germany)


    We report on the experimental investigation of gluing bifurcations in the analog electronic circuit which models a dynamical system of the third order: Lorenz equations with an additional quadratic nonlinearity. Variation of one of the resistances in the circuit changes the coefficient at this nonlinearity and replaces the Lorenz route to chaos by a different scenario which leads, through the sequence of homoclinic bifurcations, from periodic oscillations of the voltage to the irregular ones. Every single bifurcation “glues” in the phase space two stable periodic orbits and creates a new one, with the doubled length: a sequence of such bifurcations results in the birth of the chaotic attractor.

  8. Medieval Storytelling and Analogous Oral Traditions Today: Two Digital Databases

    Directory of Open Access Journals (Sweden)

    Evelyn Birge Vitz


    Full Text Available This essay presents two open-access digital databases of video clips of modern performances of medieval narratives and analogous living oral storytelling traditions: Performing Medieval Narrative Today: A Video Showcase and Arthurian Legend in Performance. To help people recognize the performability of medieval narratives, these websites offer examples of medieval-type storytelling that are still alive today in various parts of the world, as well as clips from performances of medieval narrative created by a new generation of storytellers.

  9. Martian weathering processes: Terrestrial analog and theoretical modeling studies (United States)

    McAdam, Amy Catherine


    Understanding the role of water in the Martian near-surface, and its implications for possible habitable environments, is among the highest priorities of NASA's Mars Exploration Program. Characterization of alteration signatures in surface materials provides the best opportunity to assess the role of water on Mars. This dissertation investigates Martian alteration processes through analyses of Antarctic analogs and numerical modeling of mineral-fluid interactions. Analog work involved studying an Antarctic diabase, and associated soils, as Mars analogs to understand weathering processes in cold, dry environments. The soils are dominated by primary basaltic minerals, but also contain phyllosilicates, salts, iron oxides/oxyhydroxides, and zeolites. Soil clay minerals and zeolites, formed primarily during deuteric or hydrothermal alteration of the parent rock, were subsequently transferred to the soil by physical rock weathering. Authigenic soil iron oxides/oxyhydroxides and small amounts of poorly-ordered secondary silicates indicate some contributions from low-temperature aqueous weathering. Soil sulfates, which exhibit a sulfate- aerosol-derived mass-independent oxygen isotope signature, suggest contributions from acid aerosol-rock interactions. The complex alteration history of the Antarctic materials resulted in several similarities to Martian materials. The processes that affected the analogs, including deuteric/ hydrothermal clay formation, may be important in producing Martian surface materials. Theoretical modeling focused on investigating the alteration of Martian rocks under acidic conditions and using modeling results to interpret Martian observations. Kinetic modeling of the dissolution of plagioclase-pyroxene mineral mixtures under acidic conditions suggested that surfaces with high plagioclase/pyroxene, such as several northern regions, could have experienced some preferential dissolution of pyroxenes at a pH less than approximately 3-4. Modeling of the

  10. Circuits and electronics hands-on learning with analog discovery

    CERN Document Server

    Okyere Attia, John


    The book provides instructions on building circuits on breadboards, connecting the Analog Discovery wires to the circuit under test, and making electrical measurements. Various measurement techniques are described and used in this book, including: impedance measurements, complex power measurements, frequency response measurements, power spectrum measurements, current versus voltage characteristic measurements of diodes, bipolar junction transistors, and Mosfets. The book includes end-of-chapter problems for additional exercises geared towards hands-on learning, experimentation, comparisons between measured results and those obtained from theoretical calculations.

  11. Analysis and application of analog electronic circuits to biomedical instrumentation

    CERN Document Server

    Northrop, Robert B


    All chapters include an introduction and chapter summary.Sources and Properties of Biomedical SignalsSources of Endogenous Bioelectric SignalsNerve Action PotentialsMuscle Action PotentialsThe ElectrocardiogramOther BiopotentialsElectrical Properties of BioelectrodesExogenous Bioelectric SignalsProperties and Models of Semiconductor Devices Used in Analog Electronic Systemspn Junction DiodesMidfrequency Models for BJT BehaviorMidfrequency Models for Field-Effect TransistorsHigh-Frequency Models for Transistors and Simple Transistor AmplifiersPhotons, Photodiodes, Photoconductors, LEDs, and Las

  12. Synthesis and Antitumor Activity of Triazole-Containing Sorafenib Analogs

    Directory of Open Access Journals (Sweden)

    Wenjing Ye


    Full Text Available Using a highly effective binuclear Cu complex as the catalyst, the 1,3-dipolar cycloaddition reactions between 16 alkynes and two azides were successfully performed and resulted in the production of 25 new triazole-containing sorafenib analogs. Several compounds were evaluated as potent antitumor agents. Among them, 4-(4-(4-(3-fluorophenyl-1H-1,2,3-triazol-1-ylphenoxy-N-methylpicolinamide (8f potently suppressed the proliferation of HT-29 cancer cells by inducing apoptosis and almost completely inhibited colony formation at a low micromolar concentration.

  13. 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.

  14. A Novel Green Synthesis of Thalidomide and Analogs

    Directory of Open Access Journals (Sweden)

    Ellis Benjamin


    Full Text Available Thalidomide and its derivatives are currently under investigation for their antiangiogenic, immunomodulative, and anticancer properties. Current methods used to synthesize these compounds involve multiple steps and extensive workup procedures. Described herein is an efficient microwave irradiation green synthesis method that allows preparation of thalidomide and its analogs in a one-pot multicomponent synthesis system. The multicomponent synthesis system developed involves an array of cyclic anhydrides, glutamic acid, and ammonium chloride in the presence of catalytic amounts of 4-N,N-dimethylaminopyridine (DMAP to produce thalidomide and structurally related compounds within minutes in good isolated yields.

  15. 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.

  16. Scattering and structures essentials and analogies in quantum physics

    CERN Document Server

    Povh, Bogdan


    Quantum physics may appear complicated, especially if one forgets the "big picture" and gets lost in the details. However, it can become clearer and less tangled if one applies a few fundamental concepts so that simplified approaches can emerge and estimated orders of magnitude become clear. Povh and Rosina’s Scattering and Structures presents the properties of quantum systems (elementary particles, nucleons, atoms, molecules, quantum gases, quantum liquids, stars, and early universe) with the help of elementary concepts and analogies between these seemingly different systems. In this new edition, sections on quantum gases and an up to date overview of elementary particles have been added.

  17. High-Voltage Digital-To-Analog Converter (United States)

    Huston, Steven W.


    High-voltage 10-bit digital-to-analog converter operates under computer control to put out voltages up to 500 V at currents up to 35 mA. Circuit includes high-voltage power supply used to generate high-voltage square wave at frequency set by computer at value between 0.2 Hz and 10 Hz. Used to drive 0.02-microfarad, 1-kV capacitor at slewing rate of 1 V/microsecond to provide signal for robotic imaging system.

  18. Modern analog filter analysis and design a practical approach

    CERN Document Server

    Raut, R


    Starting from the fundamentals, the present book describes methods of designing analog electronic filters and illustrates these methods by providing numerical and circuit simulation programs. The subject matters comprise many concepts and techniques that are not available in other text books on the market. To name a few - principle of transposition and its application in directly realizing current mode filters from well known voltage mode filters; an insight into the technological aspect of integrated circuit components used to implement an integrated circuit filter; a careful blending of basi

  19. [Mammary analog secretory carcinoma of the parotid gland]. (United States)

    Guérin, Maxime; Diedhiou, Abdoulaye; Nallet, Emmanuel; Duflo, Suzy; Laé, Marick; Wassef, Michel


    Mammary analog secretory carcinoma (MASC) of the parotid gland is a rare and recently described lesion. We report the case of a 46-year-old man with a tumor of the parotid gland which was carried to the diagnosis of MASC. Diagnostic was confirmed by highlighting the ETV6-NTRK3 gene translocation. However, some morphologic and immunohistochemical features are suggestive of this entity. This carcinoma should be distinguished from its main differential diagnoses: acinic cell carcinoma and low grade cribriform cystadenocarcinoma. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  20. An efficient, optimized synthesis of fentanyl and related analogs.

    Directory of Open Access Journals (Sweden)

    Carlos A Valdez

    Full Text Available The alternate and optimized syntheses of the parent opioid fentanyl and its analogs are described. The routes presented exhibit high-yielding transformations leading to these powerful analgesics after optimization studies were carried out for each synthetic step. The general three-step strategy produced a panel of four fentanyls in excellent yields (73-78% along with their more commonly encountered hydrochloride and citric acid salts. The following strategy offers the opportunity for the gram-scale, efficient production of this interesting class of opioid alkaloids.

  1. Analogies in physics textbooks for the final grade of primary school

    Directory of Open Access Journals (Sweden)

    Pavlović Zlatko


    Full Text Available The introductory part of the paper discusses some of the issues related to use of analogies in education and provides an overview of the basic foundations of the Structure- mapping theory - the theory that describes the way the analogies function. The second part of the paper presents the results of the analysis of the use of analogies in eighth-grade physics textbooks that are used in primary schools in Serbia. The results have shown that the frequency of using analogies is in the range usual for the textbooks of this type. Verbal analogies are dominant compared to the image and verbal and image analogies. Analogies are, proportionally, used most for the most abstract contents and the contents that are farthest from everyday students’ experience. When it comes to complexity, enriched analogies prevail, while the number of simple and extended analogies is significantly smaller. Textbook authors are sensitive towards the demand that the field which is the basis of analogy has to be well-known to students. In almost half of analogies the source domain was taken from everyday life experience of students.


    NARCIS (Netherlands)



    In vivo treatment with GnRH or with GnRH agonistic analog (AG), but not with GnRH antagonistic analog (ANT), depleted the LH stores of the rat pituitary gland. This depletion was potentiated by oestradiol. Oestradiol augmented the in vitro LH response of the pituitary gland to GnRH. This augmenting

  3. When Are Analogies the Right Tool? A Look at the Strategic Use of Analogies in Teaching Cellular Respiration to Middle-School Students. (United States)

    Else, Mary Jane; Ramirez, Mary Anne; Clement, John

    In this paper, the ways in which analogies are used in the Energy and the Human Body curriculum will be examined and some preliminary assessments of successes and difficulties will be discussed. Also investigated will be what the first year's study trials suggest about the effective use of analogies in the middle-school classroom. Characteristics…

  4. Teaching and learning high school physics through analogies: A case study of Kenyan classrooms (United States)

    Nashon, Samson Madera


    Analogy is a widely used instructional tool in science. Because of the many abstract concepts the subject embodies, analogy use is particularly common in physics education. Analogies differ in character depending on who constructs them, the context in which they are used and the grade level being taught. This study describes the analogies that physics teachers use in teaching form two (grade 10) physics in Kenya. The study extended over 14 weeks of classroom observation in three form two physics classes, supplemented by teacher and student interviews. A total of 20 analogies were identified and analysed in terms of Nashon's (2000) Working With Analogies (WWA) model. Findings showed that the analogies were largely environmental (cultural), anthropomorphic and spontaneously generated. There was no evidence to indicate teachers' use of a theoretical model, such as Zeitoun's (1984) General Model for Analogical Teaching (GMAT), Glynn's (1991) Teaching With Analogies (TWA) or Nashon's (2000) Working With Analogies (WWA) model. It was found that alternative frameworks for some concepts still existed among the students despite the analogical teaching. Some of the frameworks appeared to persist even in the presence of correct information, while others were a consequence of literal interpretation of scientific terms or phrases. The few analogies that students generated for themselves reflected their understanding of analogically taught concepts (Pittman, 1999) and could therefore, to some extent be judged successful. However, some misconceptions were still noticeable. Findings of this study may have an impact on the way teachers teach science, and, more so, physics---in particular, on the analogies they use, the concepts they teach and the methods they chose to use in teaching the concepts (in general), all of which depend on the context.

  5. Development of neuropeptide analogs capable of traversing the integument: A case study using diapause hormone analogs in Helicoverpa zea. (United States)

    Zhang, Qirui; Nachman, Ronald J; Kaczmarek, Krzysztof; Kierus, Krzysztof; Zabrocki, Janusz; Denlinger, David L


    Diapause hormone and its analogs terminate pupal diapause in Helicoverpa zea when injected, but if such agents are to be used as effective diapause disruptors it will be essential to develop simple techniques for administering active compounds that can exert their effect by penetrating the insect epidermis. In the current study, we used two molecules previously shown to have high diapause-terminating activity as lead molecules to rationally design and synthesize new amphiphilic compounds with modified hydrophobic components. An assay for diapause termination identified 13 active compounds with EC50's ranging from 0.9 to 46.0 pmol per pupa. Three compounds, Decyl-1963, Dodecyl-1967, and Heptyl-1965, selected from the 13 compounds most active in breaking diapause following injection, also successfully prevented newly-formed pupae from entering diapause when applied topically. These compounds feature straight-chain, aliphatic hydrocarbons from 7 to 12 carbons in length; DH analogs with either a short-chain length of 4 or an aromatic phenethyl group failed to act topically. Compared to a high diapause incidence of 80-90% in controls, diapause incidence in pupae receiving a 10 nmole topical application of Decyl-1963, Dodecyl-1967, or Heptyl-1965 dropped to 30-45%. Decyl-1963 and Dodecyl-1967 also remained effective when topically applied at the 1 nmole level. These results suggest the feasibility of developing DH agonists that can be applied topically and suggest the identity of new lead molecules for development of additional topically-active DH analogs. The ability to penetrate the insect epidermis and/or midgut lining is critical if such agents are to be considered for future use as pest management tools. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Ultraestructural study of effects of alkylphospholipid analogs against nematodes. (United States)

    Sant' Anna, Viviane; Railbolt, Marcelle; Oliveira-Menezes, Aleksandra; Calogeropoulou, Theodora; Pinheiro, Jairo; de Souza, Wanderley


    Alkylphospholipid analogs were initially developed as anticancer agents and were later found to antiparasitic activity. Miltefosine is the prototype alkylphosphocholine and is the first oral treatment against visceral leishmaniasis. Here we investigated the effects of miltefosine and two ring-substituted alkylphosphocholine derivatives, TCAN26 and TC70, on the viability, morphology, and ultrastructure of the life stages of Caenorhabditis elegans and infective larvae of the parasite Strongyloides venezuelensis. Miltefosine displayed activity against C. elegans adults at low concentrations and was more effective than TCAN26 and TC70. Miltefosine inhibited the hatching of eggs, leading to embryonic lethality, and showed larvicidal activity against C. elegans and S. venezuelensis larvae after 24 h. Mitelfosine also induced alterations in the reproductive system of hermaphrodites, causing vulvar prolapse and general effects in the body wall. Electron microscopy analysis showed that miltefosine induced selective embryonic lethality, leading to cell death. Our results suggest that alkylphospholipid analogs are a potential new alternative for anti-nematode chemotherapy. Copyright © 2018. Published by Elsevier Inc.

  7. Tribotronic Tuning Diode for Active Analog Signal Modulation. (United States)

    Zhou, Tao; Yang, Zhi Wei; Pang, Yaokun; Xu, Liang; Zhang, Chi; Wang, Zhong Lin


    Realizing active interaction with external environment/stimuli is a great challenge for current electronics. In this paper, a tribotronic tuning diode (TTD) is proposed by coupling a variable capacitance diode and a triboelectric nanogenerator in free-standing sliding mode. When the friction layer is sliding on the device surface for electrification, a reverse bias voltage is created and applied to the diode for tuning the junction capacitance. When the sliding distance increases from 0 to 25 mm, the capacitance of the TTD decreases from about 39 to 8 pF. The proposed TTD has been integrated into analog circuits and exhibited excellent performances in frequency modulation, phase shift, and filtering by sliding a finger. This work has demonstrated tunable diode and active analog signal modulation by tribotronics, which has great potential to replace ordinary variable capacitance diodes in various practical applications such as signal processing, electronic tuning circuits, precise tuning circuits, active sensor networks, electronic communications, remote controls, flexible electronics, etc.

  8. Photonic analog-to-digital converter via asynchronous oversampling (United States)

    Carver, Spencer; Reeves, Erin; Siahmakoun, Azad; Granieri, Sergio


    This paper presents a hybrid opto-electronic asynchronous delta-sigma modulator, implemented in the form of a fiber-optic Analog-to-Digital converter (ADC). This architecture was chosen for its independence of an external clock and ease of demodulation through a single low-pass filter stage. The fiber-optic prototype consists of an input laser (wavelength λ1) which is modulated with an input RF signal, a high-speed comparator circuit working as bi-stable quantizer, and a fiber-optic loop that includes a SOA and a band-pass filter that act as a leaky integrator. The fiber-optic loop acts as a fiber-ring resonator (FRR), and defines the resonance wavelength λ2 of the system. The gain within this loop is modified through cross-gain modulation (XGM) by the input wavelength λ1, and thus achieves the desired modulation effect. The proposed architecture has been constructed and characterized at a sampling rate of 15.4 MS/s processing input analog signals in the range of dc-3 MHz with a signal-to-noise ratio of 36 dB and an effective number of bits of 5.7.

  9. Atom-Optical Analogs of Electronic Components and Devices (United States)

    Pepino, R. A.; Cooper, J.; Anderson, D. Z.; Holland, M. J.

    The research program known as Atomtronics aims to create one-to-one analogs of electronic components and devices with ultracold atoms trapped in periodic potentials. Such an analogy can be realized with reservoirs of neutral, ultracold atoms connected to optical lattices. Due to their highly tunable band structure, the lattices can be tailored to create resonances between certain states of the system. This allows atomic transport through specific dynamical pathways of the system, while minimizing transport through others. In this presentation, a quantum master equation approach is outlined for treating the problem of two or more reservoirs of ultracold atoms, with arbitrary chemical potentials, connected to optical lattice configurations. The formalism is quite general and readily lends itself to the theoretical study of transport phenomena in open atomic systems. This theoretical approach is applied to atomtronic systems, demonstrating how certain custom lattices can mimic the behavior of the electronic semiconductor diode, field effect-transistor, and bipolar junction transistor (BJT). Logic elements, such as AND and OR gates are constructed by taking two atomtronic BJTs and combining them in a manner similar to that of conventional electronics. This is promising since it is possible that we may join basic atomtronic components to construct elementary logic devices in a fully quantum mechanical system.

  10. In Vivo Efficacy and Pharmacokinetics of Optimized Apidaecin Analogs (United States)

    Schmidt, Rico; Knappe, Daniel; Wende, Elisabeth; Ostorházi, Eszter; Hoffmann, Ralf


    Proline-rich antimicrobial peptides (PrAMPs) represent promising alternative therapeutic options for the treatment of multidrug-resistant bacterial infections. PrAMPs are predominantly active against Gram-negative bacteria by inhibiting protein expression via at least two different modes of action, i.e., blocking the ribosomal exit tunnel of 70S ribosomes (oncocin-type binding) or inhibiting the assembly of the 50S ribosomal subunit (apidaecin-type binding). The in vivo efficacy and favorable biodistribution of oncocins confirmed the therapeutic potential of short PrAMPs for the first time, whereas the in vivo evaluation of apidaecins is still limited despite the promising efficacy of apidaecin-analog Api88 in an intraperitoneal murine infection model. Here, the in vivo efficacy of apidaecin-analog Api137 was studied, which rescued all NMRI mice from a lethal intraperitoneal infection with E. coli ATCC 25922 when administered three times intraperitoneal at doses of 0.6 mg/kg starting one hour after infection. When Api88 and Api137 were administered intravenous or intraperitoneal at doses of 5 and 20 mg/kg, their plasma levels were similarly low (murine infection models and the fast clearance of Api88 and Api137 within 60 min after intravenous and 90 min after intraperitoneal injections indicate that

  11. In vitro evaluation of nicotinamide riboside analogs against Haemophilus influenzae. (United States)

    Godek, C P; Cynamon, M H


    Exogenous NAD, nicotinamide mononucleotide, or nicotinamide riboside is required for the growth of Haemophilus influenzae. These compounds have been defined as the V-factor growth requirement. We have previously shown that the internalization of nicotinamide riboside is energy dependent and carrier mediated with saturation kinetics. Thionicotinamide riboside, 3-pyridinealdehyde riboside, 3-acetylpyridine riboside, and 3-aminopyridine riboside were prepared from their corresponding NAD analogs. These compounds and several other nicotinamide riboside analogs were evaluated for their ability to support the growth of H. influenzae and for their ability to block the uptake of [carbonyl-14C]nicotinamide riboside by H. influenzae. 3-Aminopyridine riboside blocked the uptake of [carbonyl-14C]nicotinamide riboside and inhibited the growth of H. influenzae when NAD, nicotinamide mononucleotide, or nicotinamide riboside served as the V factor. The antibacterial activity of 3-aminopyridine riboside was found to be specific for H. influenzae but had no effect on the growth of Staphylococcus aureus or Escherichia coli. In additional experiments by reversed-phase high-performance liquid chromatography, it was determined that whole cells of H. influenzae degrade 3-aminopyridine adenine dinucleotide to 3-aminopyridine riboside, which is then internalized. Inside the cell, 3-aminopyridine riboside has the ability to interfere with the growth of H. influenzae by an undetermined mechanism.

  12. Radioiodinated carnitine and acylcarnitine analogs as potential myocardial imaging agents

    Energy Technology Data Exchange (ETDEWEB)

    McConnell, D.S.


    R-carnitine is extremely important in mammalian energy metabolism. Gamma-butyrobetaine, the immediate biosynthetic precursor to R-carnitine, is synthesized in many organs. However, only liver can hydroxylate gamma-butyrobetaine to carnitine. Thus the transport of carnitine from its site of synthesis to the site of utilization is of utmost importance. Carnitine is found in highest concentration in cardiac and skeletal muscle, where it is required for the transport of fatty acids into the mitochondria. Before fatty acids are utilized as fuel for the myocyte by beta-oxidation, they are bound to carnitine as an acylcarnitine ester at the 3-hydroxyl, and transported across the micochondrial membranes. R,S-Carnitine has been shown to be taken up by myocytes. The author has begun a study on the use of carnitine derivatives as potential carriers for the site-specific delivery of radioiodine to bidning sites in the myocardium. Such agents labeled with a gamma-emitting nuclide such as iodine-123 would be useful for the noninvasive imaging of these tissues. The aim was to synthesize a variety of radiolabeled analogs of carnitine and acylcarnitine to address questions of transport, binding and availability for myocardial metabolism. These analogs consist of N-alkylated derivatives of carnitine, acylcarnitine esters as well as carnitine amides and ethers. One C-alkylated derivative showed interesting biodistribution, elevated myocardial uptake and competition with carnitine for binding in the myocardium.

  13. Multi-modal Registration for Correlative Microscopy using Image Analogies (United States)

    Cao, Tian; Zach, Christopher; Modla, Shannon; Powell, Debbie; Czymmek, Kirk; Niethammer, Marc


    Correlative microscopy is a methodology combining the functionality of light microscopy with the high resolution of electron microscopy and other microscopy technologies for the same biological specimen. In this paper, we propose an image registration method for correlative microscopy, which is challenging due to the distinct appearance of biological structures when imaged with different modalities. Our method is based on image analogies and allows to transform images of a given modality into the appearance-space of another modality. Hence, the registration between two different types of microscopy images can be transformed to a mono-modality image registration. We use a sparse representation model to obtain image analogies. The method makes use of corresponding image training patches of two different imaging modalities to learn a dictionary capturing appearance relations. We test our approach on backscattered electron (BSE) scanning electron microscopy (SEM)/confocal and transmission electron microscopy (TEM)/confocal images. We perform rigid, affine, and deformable registration via B-splines and show improvements over direct registration using both mutual information and sum of squared differences similarity measures to account for differences in image appearance. PMID:24387943

  14. Natural Polyphenols and their Synthetic Analogs as Emerging Anticancer Agents. (United States)

    Colomer, Ramon; Sarrats, Ariadna; Lupu, Ruth; Puig, Teresa


    Polyphenols are a structural class of natural and synthetic organic chemicals which contain phenol units. Numerous epidemiological, preclinical and clinical studies have strongly supported their benefical effects for human health. Polyphenols group include molecules of utterly different complexity grades, ranging from simple molecules to highly polymerized structures. They are classified into: Phenolic acids, Flavonoids, Lignans and the less common Stilbenes. This work first intends to review the current studies on classification, chemical composition and metabolism of polyphenols. Then, we have reported cancer preventive and treatment effects of polyphenols, especially focused in the green tea polyphenol (GTP) (-)-Epigallocatechin-3-gallate (EGCG). Polyphenols such as EGCG and their synthetic analogs interfere in carcinogenesis by modulating and regulating multiple signaling pathways and transcription factors, membrane-associated receptor tyrosine kinases (RTKs), fatty acid metabolism and lipid rafts or methylation together with other emerging targets such as proteasome, telomerase and cancer stem cells. Here, we have reviewed several potential molecular targets of polyphenols (mainly EGCG and EGCG analogs) and their anticancer effects in cellular and animal models of different human carcinomas and we have also listed Phases I and II clinical trials conducted to study the antitumor properties of GTPs. Copyright© Bentham Science Publishers; For any queries, please email at

  15. Error Models of the Analog to Digital Converters

    Directory of Open Access Journals (Sweden)

    Michaeli Linus


    Full Text Available Error models of the Analog to Digital Converters describe metrological properties of the signal conversion from analog to digital domain in a concise form using few dominant error parameters. Knowledge of the error models allows the end user to provide fast testing in the crucial points of the full input signal range and to use identified error models for post correction in the digital domain. The imperfections of the internal ADC structure determine the error characteristics represented by the nonlinearities as a function of the output code. Progress in the microelectronics and missing information about circuital details together with the lack of knowledge about interfering effects caused by ADC installation prefers another modeling approach based on the input-output behavioral characterization by the input-output error box. Internal links in the ADC structure cause that the input-output error function could be described in a concise form by suitable function. Modeled functional parameters allow determining the integral error parameters of ADC. Paper is a survey of error models starting from the structural models for the most common architectures and their linkage with the behavioral models represented by the simple look up table or the functional description of nonlinear errors for the output codes.

  16. Multimode lasers as analogs of complex biological systems (a survey) (United States)

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


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

  17. 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.

  18. Vibrational analysis of L-alanine and deuterated analogs (United States)

    Susi, Heino; Byler, D. Michael


    Raman spectra of the polycrystalline L-alanine analogs CH 3CH(NH +3)COO -, CH 3CH(ND +3)-COO -, CD 3CD(NH +3)COO -, and CD 3CD(ND +3)COO - have been obtained. A normal coordinate analysis is carried out based on the experimental frequencies of the four isotopic analogs and a 34 parameter valence-type force field defined in terms of local symmetry coordinates. The final refinement, in which five stretching force constants are constrained to fixed values obtained from bond length data, results in an average error of 7 cm -1 (0.9%) for the observed frequencies of the four isotopically substituted molecules. Band assignments are given in terms of the potential energy distribution for local symmetry coordinates. For non-deuterated L-alanine, the vibrations above 1420 cm -1 and below 950 cm -1 may be described as localized group vibrations. By contrast, the eight modes in the middle frequency range, viz. the three skeletal stretching, the COO - symmetric stretching, one NH +3 rocking, the symmetric CH 3 deformation, and the two methyne CH deformation vibrations, are very strongly coupled to one another. Some decoupling appears to take place in the perdeutero molecule, and all but five modes can be described as localized group vibrations.

  19. Multi-modal registration for correlative microscopy using image analogies. (United States)

    Cao, Tian; Zach, Christopher; Modla, Shannon; Powell, Debbie; Czymmek, Kirk; Niethammer, Marc


    Correlative microscopy is a methodology combining the functionality of light microscopy with the high resolution of electron microscopy and other microscopy technologies for the same biological specimen. In this paper, we propose an image registration method for correlative microscopy, which is challenging due to the distinct appearance of biological structures when imaged with different modalities. Our method is based on image analogies and allows to transform images of a given modality into the appearance-space of another modality. Hence, the registration between two different types of microscopy images can be transformed to a mono-modality image registration. We use a sparse representation model to obtain image analogies. The method makes use of corresponding image training patches of two different imaging modalities to learn a dictionary capturing appearance relations. We test our approach on backscattered electron (BSE) scanning electron microscopy (SEM)/confocal and transmission electron microscopy (TEM)/confocal images. We perform rigid, affine, and deformable registration via B-splines and show improvements over direct registration using both mutual information and sum of squared differences similarity measures to account for differences in image appearance. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Optomechanical Analogy for Toy Cosmology with Quantized Scale Factor

    Directory of Open Access Journals (Sweden)

    Joseph A. Smiga


    Full Text Available The simplest cosmology—the Friedmann–Robertson–Walker–Lemaître (FRW model— describes a spatially homogeneous and isotropic universe where the scale factor is the only dynamical parameter. Here we consider how quantized electromagnetic fields become entangled with the scale factor in a toy version of the FRW model. A system consisting of a photon, source, and detector is described in such a universe, and we find that the detection of a redshifted photon by the detector system constrains possible scale factor superpositions. Thus, measuring the redshift of the photon is equivalent to a weak measurement of the underlying cosmology. We also consider a potential optomechanical analogy system that would enable experimental exploration of these concepts. The analogy focuses on the effects of photon redshift measurement as a quantum back-action on metric variables, where the position of a movable mirror plays the role of the scale factor. By working in the rotating frame, an effective Hubble equation can be simulated with a simple free moving mirror.

  1. NASA Software Cost Estimation Model: An Analogy Based Estimation Model (United States)

    Hihn, Jairus; Juster, Leora; Menzies, Tim; Mathew, George; Johnson, James


    The cost estimation of software development activities is increasingly critical for large scale integrated projects such as those at DOD and NASA especially as the software systems become larger and more complex. As an example MSL (Mars Scientific Laboratory) developed at the Jet Propulsion Laboratory launched with over 2 million lines of code making it the largest robotic spacecraft ever flown (Based on the size of the software). Software development activities are also notorious for their cost growth, with NASA flight software averaging over 50% cost growth. All across the agency, estimators and analysts are increasingly being tasked to develop reliable cost estimates in support of program planning and execution. While there has been extensive work on improving parametric methods there is very little focus on the use of models based on analogy and clustering algorithms. In this paper we summarize our findings on effort/cost model estimation and model development based on ten years of software effort estimation research using data mining and machine learning methods to develop estimation models based on analogy and clustering. The NASA Software Cost Model performance is evaluated by comparing it to COCOMO II, linear regression, and K-­ nearest neighbor prediction model performance on the same data set.

  2. 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

  3. 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.

  4. Normal fault growth in analog models and on Mars (United States)

    Wyrick, Danielle Y.; Morris, Alan P.; Ferrill, David A.


    Normal faults observed in extensional clay models evolve by displacement (throw) accumulation and concomitant trace length increase, and by segment linkage. The first of these processes leads to an increase in the maximum throw to trace length ( Dmax/ L) ratio, whereas the second leads to a decrease in this ratio. With increasing extension individual faults evolve along stepwise tracks in Dmax/ L parameter space, although at any given time a summary plot of Dmax versus L for the entire fault population will typically span one order of magnitude in Dmax/ L ratio and two orders of magnitude in trace length, obscuring the stepwise nature of fault evolution and giving the impression of self-similar fault growth along a locus of constant Dmax/ L ratio. In addition, the number of simple faults (faults with a single throw maximum) incorporated into a compound fault (a fault with multiple throw maxima) is strongly correlated with the fault's trace length, indicating that trace length increase is dominated by linkage not throw accumulation. When analyzed for evidence of relict simple faults (expressed as throw maxima), normal faults observed on Mars exhibit similar characteristics to those developed in analog clay models. By analogy, we infer that Mars normal faults evolve in a similar fashion to faults in clay models.

  5. 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

  6. Human performance profiles for planetary analog extra-vehicular activities: 120 day and 30 day analog missions (United States)

    Swarmer, Tiffany M.

    Understanding performance factors for future planetary missions is critical for ensuring safe and successful planetary extra-vehicular activities (EVAs). The goal of this study was to gain operational knowledge of analog EVAs and develop biometric profiles for specific EVA types. Data was collected for a 120 and 30 day analog planetary exploration simulation focusing on EVA type, pre and post EVA conditions, and performance ratings. From this five main types of EVAs were performed: maintenance, science, survey/exploratory, public relations, and emergency. Each EVA type has unique characteristics and performance ratings showing specific factors in chronological components, environmental conditions, and EVA systems that have an impact on performance. Pre and post biometrics were collected to heart rate, blood pressure, and SpO2. Additional data about issues and specific EVA difficulties provide some EVA trends illustrating how tasks and suit comfort can negatively affect performance ratings. Performance decreases were noted for 1st quarter and 3rd quarter EVAs, survey/exploratory type EVAs, and EVAs requiring increased fine and gross motor function. Stress during the simulation is typically higher before the EVA and decreases once the crew has returned to the habitat. Stress also decreases as the simulation nears the end with the 3rd and 4th quarters showing a decrease in stress levels. Operational components and studies have numerous variable and components that effect overall performance, by increasing the knowledge available we may be able to better prepare future crews for the extreme environments and exploration of another planet.

  7. A Direct Conversion Receiver Adopting Balanced Three-Phase Analog System (United States)

    Yamaji, Takafumi; Ueno, Takeshi; Itakura, Tetsuro

    Recent advanced technology makes digital circuits small and the number of digital functional blocks that can be integrated on a single chip is increasing rapidly. On the other hand, reduction in the size of analog circuits has been insufficient. This means that the analog circuit area is relatively large, and reducing analog circuit area can be effective to make a low cost radio receiver. In this paper, a new wireless receiver architecture that occupies small analog area is proposed, and measured results of the core analog blocks are described. To reduce the analog area, a balanced 3-phase analog system is adopted and the functions of analog baseband filters and VGAs are moved to the digital domain. The test chip consists of a 3-phase downconverter and a 3-phase ADC. There is no analog baseband filter on the chip and the analog filter is assumed to be replaced with a digital filter. The downconverter and ADC occupy 0.28mm2. The measured results show the possibility that the requirements for IMT-2000 are fulfilled even with a small chip area.

  8. Abstract analogical reasoning in high-functioning children with autism spectrum disorders. (United States)

    Green, Adam E; Kenworthy, Lauren; Mosner, Maya G; Gallagher, Natalie M; Fearon, Edward W; Balhana, Carlos D; Yerys, Benjamin E


    Children with autism spectrum disorders (ASD) exhibit a deficit in spontaneously recognizing abstract similarities that are crucial for generalizing learning to new situations. This may contribute to deficits in the development of appropriate schemas for navigating novel situations, including social interactions. Analogical reasoning is the central cognitive mechanism that enables typically developing children to understand abstract similarities between different situations. Intriguingly, studies of high-functioning children with ASD point to a relative cognitive strength in basic, nonabstract forms of analogical reasoning. If this analogical reasoning ability extends to abstract analogical reasoning (i.e., between superficially dissimilar situations), it may provide a bridge between a cognitive capability and core ASD deficits in areas such as generalization and categorization. This study tested whether preserved analogical reasoning abilities in ASD can be extended to abstract analogical reasoning, using photographs of real-world items and situations. Abstractness of the analogies was determined via a quantitative measure of semantic distance derived from latent semantic analysis. Children with ASD performed as well as typically developing children at identifying abstract analogical similarities when explicitly instructed to apply analogical reasoning. Individual differences in abstract analogical reasoning ability predicted individual differences in a measure of social function in the ASD group. Preliminary analyses indicated that children with ASD, but not typically developing children, showed an effect of age on abstract analogical reasoning. These results provide new evidence that children with ASD are capable of identifying abstract similarities through analogical reasoning, pointing to abstract analogical reasoning as a potential lever for improving generalization skills and social function in ASD. © 2014 International Society for Autism Research, Wiley

  9. Manning’s equation and two-dimensional flow analogs (United States)

    Hromadka, T. V., II; Whitley, R. J.; Jordan, N.; Meyer, T.


    SummaryTwo-dimensional (2D) flow models based on the well-known governing 2D flow equations are applied to floodplain analysis purposes. These 2D models numerically solve the governing flow equations simultaneously or explicitly on a discretization of the floodplain using grid tiles or similar tile cell geometry, called "elements". By use of automated information systems such as digital terrain modeling, digital elevation models, and GIS, large-scale topographic floodplain maps can be readily discretized into thousands of elements that densely cover the floodplain in an edge-to-edge form. However, the assumed principal flow directions of the flow model analog, as applied across an array of elements, typically do not align with the floodplain flow streamlines. This paper examines the mathematical underpinnings of a four-direction flow analog using an array of square elements with respect to floodplain flow streamlines that are not in alignment with the analog's principal flow directions. It is determined that application of Manning's equation to estimate the friction slope terms of the governing flow equations, in directions that are not coincident with the flow streamlines, may introduce a bias in modeling results, in the form of slight underestimation of flow depths. It is also determined that the maximum theoretical bias, occurs when a single square element is rotated by about 13°, and not 45° as would be intuitively thought. The bias as a function of rotation angle for an array of square elements follows approximately the bias for a single square element. For both the theoretical single square element and an array of square elements, the bias as a function of alignment angle follows a relatively constant value from about 5° to about 85°, centered at about 45°. This bias was first noted about a decade prior to the present paper, and the magnitude of this bias was estimated then to be about 20% at about 10° misalignment. An adjustment of Manning's n is

  10. Developing selective histone deacetylases (HDACs inhibitors through ebselen and analogs

    Directory of Open Access Journals (Sweden)

    Wang Y


    Full Text Available Yuren Wang,1 Jason Wallach,2 Stephanie Duane,1 Yuan Wang,1 Jianghong Wu,1 Jeffrey Wang,1 Adeboye Adejare,2 Haiching Ma1 1Reaction Biology Corp., Malvern, 2Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, USA Abstract: Histone deacetylases (HDACs are key regulators of gene expression in cells and have been investigated as important therapeutic targets for cancer and other diseases. Different subtypes of HDACs appear to play disparate roles in the cells and are associated with specific diseases. Therefore, substantial effort has been made to develop subtype-selective HDAC inhibitors. In an effort to discover existing scaffolds with HDAC inhibitory activity, we screened a drug library approved by the US Food and Drug Administration and a National Institutes of Health Clinical Collection compound library in HDAC enzymatic assays. Ebselen, a clinical safe compound, was identified as a weak inhibitor of several HDACs, including HDAC1, HDAC3, HDAC4, HDAC5, HDAC6, HDAC7, HDAC8, and HDAC9 with half maximal inhibitory concentrations approximately single digit of µM. Two ebselen analogs, ebselen oxide and ebsulfur (a diselenide analog of ebselen, also inhibited these HDACs, however with improved potencies on HDAC8. Benzisothiazol, the core structure of ebsulfur, specifically inhibited HDAC6 at a single digit of µM but had no inhibition on other HDACs. Further efforts on structure–activity relationship based on the core structure of ebsulfur led to the discovery of a novel class of potent and selective HDAC6 inhibitors with RBC-2008 as the lead compound with single-digit nM potency. This class of histone deacetylase inhibitor features a novel pharmacophore with an ebsulfur scaffold selectively targeting HDAC6. Consistent with its inhibition on HDAC6, RBC-2008 significantly increased the acetylation levels of α-tubulin in PC-3 cells. Furthermore, treatment with these compounds led to

  11. Update on taxane development: new analogs and new formulations

    Directory of Open Access Journals (Sweden)

    Yared JA


    Full Text Available Jean A Yared, Katherine HR TkaczukUniversity of Maryland School of Medicine, Marlene and Stewart Greenebaum Cancer Center, Baltimore, MD, USAAbstract: The taxanes (paclitaxel and docetaxel represent an important class of antineoplastic agents that interfere with microtubule function leading to altered mitosis and cellular death. Paclitaxel (Taxol® was originally extracted from a yew tree (Taxus spp., Taxaceae a small slow-growing evergreen, coniferous tree. Due to the initial scarcity of paclitaxel, docetaxel (Taxotere® a semisynthetic analog of paclitaxel produced from the needles of European yew tree, Taxus baccata was developed. Docetaxel differs from paclitaxel in two positions in its chemical structure and this small alteration makes it more water soluble. Today, paclitaxel and docetaxel are widely prescribed antineoplastic agents for a broad range of malignancies including lung cancer, breast cancer, prostate cancer, Kaposi’s sarcoma, squamous cell carcinoma of the head and neck, gastric cancer, esophageal cancer, bladder cancer, and other carcinomas. Although very active clinically, paclitaxel and docetaxel have several clinical problems including poor drug solubility, serious dose-limiting toxicities such as myelosuppression, peripheral sensory neuropathy, allergic reactions, and eventual development of drug resistance. A number of these side effects have been associated with the solvents used for dilution of these antineoplastic agents: Cremophor EL for paclitaxel and polysorbate 80 for docetaxel. In addition, reports have linked these solvents to the alterations in paclitaxel and docetaxel pharmacokinetic profiles. In this review, we provide preclinical and clinical data on several novel taxanes formulations and analogs which are currently US Food and Drug Administration (FDA-approved or in clinical development in various solid tumor malignancies. Of the new taxanes nab-paclitaxel and cabazitaxel have enjoyed clinical success and

  12. From Analog to Digital Medias in Early Childhood Education

    DEFF Research Database (Denmark)

    Brandt, Erika Zimmer


    . Research shows that there are both potential pedagogical difficulties and possibilities connected to using digital media (ex. Thestrup 2015, Tække and Paulsen 2014) Theoretical and conceptual framework: The study is a single case study of an educational experiment (Flyvbjerg 2006). It is carried out......Research aims: The aim of the study is to explore how the encounters between children and their educators alter when the media changes from analog to digital. Relationship to previous research works Tablets and other handheld, electronic devices has become part of everyday life in kindergartens...... Considerations: A changed media environment reveals a kind of social vacuum. Educators find themselves lacking norms for how to interact in this new reality. This lack of knowhow and experience in this specific area of professionalism creates uncertainty and vulnerability in the informants which require micro...

  13. Semantics, analogy and alternation capacity of syntactic structures

    Directory of Open Access Journals (Sweden)

    Stanojčić Živojin S.


    Full Text Available Departing from examples found in the language of Njegoš and later writers from a broader area, and on the theoretical premises of cognitive linguistics as well as on transformational grammar methodology, author is discussing the syntactic and semantic elements that enable the alternations of conjunctions gde, što, kako and da - mutually and with other dependent clauses conjunctions the semantic basis of which are the notions “cause”, “space”, “manner of an action” and “object of an action”. According to author, in the given process, with inner linguistic semantic and analogical factors, the idiolectal experience of speaker / writer (listener / reader and his/her knowledge of language units in the common language of the given society - have the most important role in the event of language perception.

  14. Eastern Sahara Geology from Orbital Radar: Potential Analog to Mars (United States)

    Farr, T. G.; Paillou, P.; Heggy, E.


    Much of the surface of Mars has been intensely reworked by aeolian processes and key evidence about the history of the Martian environment seems to be hidden beneath a widespread layer of debris (paleo lakes and rivers, faults, impact craters). In the same way, the recent geological and hydrological history of the eastern Sahara is still mainly hidden under large regions of wind-blown sand which represent a possible terrestrial analog to Mars. The subsurface geology there is generally invisible to optical remote sensing techniques, but radar images obtained from the Shuttle Imaging Radar (SIR) missions were able to penetrate the superficial sand layer to reveal parts of paleohydrological networks in southern Egypt.

  15. Structure-Dependent Immune Modulatory Activity of Protegrin-1 Analogs

    Directory of Open Access Journals (Sweden)

    Susu M. Zughaier


    Full Text Available Protegrins are porcine antimicrobial peptides (AMPs that belong to the cathelicidin family of host defense peptides. Protegrin-1 (PG-1, the most investigated member of the protegrin family, is an arginine-rich peptide consisting of 18 amino acid residues, its main chain adopting a β-hairpin structure that is linked by two disulfide bridges. We report on the immune modulatory activity of PG-1 and its analogs in neutralizing bacterial endotoxin and capsular polysaccharides, consequently inhibiting inflammatory mediators’ release from macrophages. We demonstrate that the β-hairpin structure motif stabilized with at least one disulfide bridge is a prerequisite for the immune modulatory activity of this type of AMP.

  16. Nonequilibrium sensing and its analogy to kinetic proofreading (United States)

    Hartich, David; Barato, Andre C.; Seifert, Udo


    For a paradigmatic model of chemotaxis, we analyze the effect of how a nonzero affinity driving receptors out of equilibrium affects sensitivity. This affinity arises whenever changes in receptor activity involve adenosine triphosphate hydrolysis. The sensitivity integrated over a ligand concentration range is shown to be enhanced by the affinity, providing a measure of how much energy consumption improves sensing. With this integrated sensitivity we can establish an intriguing analogy between sensing with nonequilibrium receptors and kinetic proofreading: the increase in integrated sensitivity is equivalent to the decrease of the error in kinetic proofreading. The influence of the occupancy of the receptor on the phosphorylation and dephosphorylation reaction rates is shown to be crucial for the relation between integrated sensitivity and affinity. This influence can even lead to a regime where a nonzero affinity decreases the integrated sensitivity, which corresponds to anti-proofreading.

  17. Challenges of VDD scaling for analog circuits: an amplifier

    Directory of Open Access Journals (Sweden)

    A. Bargagli-Stoffi


    Full Text Available With the shrinking of the device dimensions, the power supply voltage value is continuously decreasing. Since the threshold voltage value does not decrease as much as the power supply and the drain source saturation voltage becomes an important fraction of the power supply, many amplifier architectures are no more suitable for modern processes. A transconductance amplifier based on current mirrors is analyzed highlighting the main challenges of a low-voltage analog design. Among the many proposed amplifier architectures, a topology based on current mirrors has been chosen as the most promising to operate with low voltages. Simulations with 90nm CMOS prove the feasibility of circuit operation with satisfactory performance at an operating power supply voltage as low as 0.6V.

  18. Design techniques for low-voltage analog integrated circuits (United States)

    Rakús, Matej; Stopjaková, Viera; Arbet, Daniel


    In this paper, a review and analysis of different design techniques for (ultra) low-voltage integrated circuits (IC) are performed. This analysis shows that the most suitable design methods for low-voltage analog IC design in a standard CMOS process include techniques using bulk-driven MOS transistors, dynamic threshold MOS transistors and MOS transistors operating in weak or moderate inversion regions. The main advantage of such techniques is that there is no need for any modification of standard CMOS structure or process. Basic circuit building blocks like differential amplifiers or current mirrors designed using these approaches are able to operate with the power supply voltage of 600 mV (or even lower), which is the key feature towards integrated systems for modern portable applications.

  19. 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.

  20. Activity and Export of Engineered Nisin-(1-22 Analogs

    Directory of Open Access Journals (Sweden)

    Rick Rink


    Full Text Available The pentacyclic peptide antibiotic nisin, produced by Lactococcus lactis is ubiquitously applied as a food preservative. We previously demonstrated that the truncated nisin-(1-22 has only 10-fold lower activity than nisin. Here we aimed at further developing this tricyclic nisin analog to reach activity comparable to that of nisin. Our data demonstrate that: (1 ring A has a large mutational freedom; (2 the composition of residues 20–22 strongly affects production levels of nisin-(1-22; (3 a positively charged C-terminus of nisin-(1-22 significantly enhances its antimicrobial activity; (4 nisin-(1-22 inhibits in vitro growth of a target strain using different dynamics than nisin.

  1. On analog simulation of ionization cooling of muons

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Ming


    Analog simulation, proposed here as an alternative approach for the study of ionization cooling of muons, is a scaled cooling experiment, using protons instead of muons as simulation particles. It is intended to be an effective and flexible, quick and inexpensive experiment for the understanding and validation of unprecedentedly complicated cooling physics, for the demonstration and optimization of various elaborated techniques for beam manipulation in 6D phase space. It can be done and perhaps should be done before the costly and time-consuming development of extremely challenging, muon-specific cooling technology. In a nutshell, the idea here is to build a toy machine in a playground of ideas, before staking the Imperial Guard of Napoleon into the bloody battlefield of Waterloo.

  2. An Analog Correlator for Ultra-Wideband Receivers

    Directory of Open Access Journals (Sweden)

    Tu Chunjiang


    Full Text Available We present a new analog circuit exhibiting high bandwidth and low distortion, specially designed for signal correlation in an ultra-wideband receiver front end. The ultra-wideband short impulse signals are correlated with a local pulse template by the correlator. A comparator then samples the output for signal detection. A typical Gilbert mixer core is adopted for multiplication of broadband signals up to . As a result of synchronization of the received signal and the local template, the output voltage level after integration and sampling can reach up to , which is sufficient for detection by the comparator. The circuit dissipates about from double voltage supplies of and using SiGe BiCMOS technology. Simulation results are presented to show the feasibility of this circuit design for use in ultra-wideband receivers.

  3. High fidelity, radiation tolerant analog-to-digital converters (United States)

    Wang, Charles Chang-I (Inventor); Linscott, Ivan Richard (Inventor); Inan, Umran S. (Inventor)


    Techniques for an analog-to-digital converter (ADC) using pipeline architecture includes a linearization technique for a spurious-free dynamic range (SFDR) over 80 deciBels. In some embodiments, sampling rates exceed a megahertz. According to a second approach, a switched-capacitor circuit is configured for correct operation in a high radiation environment. In one embodiment, the combination yields high fidelity ADC (>88 deciBel SFDR) while sampling at 5 megahertz sampling rates and consuming ADC displays no latchup up to a highest tested linear energy transfer of 63 million electron Volts square centimeters per milligram at elevated temperature (131 degrees C.) and supply (2.7 Volts, versus 2.5 Volts nominal).

  4. 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.

  5. Graphene Quantum Capacitors for High Frequency Tunable Analog Applications. (United States)

    Moldovan, Clara F; Vitale, Wolfgang A; Sharma, Pankaj; Tamagnone, Michele; Mosig, Juan R; Ionescu, Adrian M


    Graphene quantum capacitors (GQC) are demonstrated to be enablers of radio-frequency (RF) functions through voltage-tuning of their capacitance. We show that GQC complements MEMS and MOSFETs in terms of performance for high frequency analog applications and tunability. We propose a CMOS compatible fabrication process and report the first experimental assessment of their performance at microwaves frequencies (up to 10 GHz), demonstrating experimental GQCs in the pF range with a tuning ratio of 1.34:1 within 1.25 V, and Q-factors up to 12 at 1 GHz. The figures of merit of graphene variable capacitors are studied in detail from 150 to 350 K. Furthermore, we describe a systematic, graphene specific approach to optimize their performance and predict the figures of merit achieved if such a methodology is applied.

  6. 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...... of sea state parameters — influence of filtering. Ocean Engineering 2007;34:1797–810.], where time series of ship responses were generated from a known wave spectrum for the purpose of the inverse process — the estimation of the underlying wave excitations. Similar response generations and vice versa...... be estimated reasonably well, even considering high-frequency wave components of a wind sea wave spectrum....

  7. Photonic digital-to-analog conversion based on wavelength multiplexing (United States)

    Yang, Shuna; Hu, Miao; Chi, Hao; Li, Qiliang


    A novel photonic digital-to-analog conversion (PDAC) scheme, which is based on optical intensity weighting and multiplexing/summing of different wavelengths, is proposed. The employment of wavelength multiplexing in the system, which conducts the function of modulated light intensity summation, greatly simplifies the system complexity and improves the conversion speed/accuracy limited by large-area photo-detectors and associated electronics. A 4-bit PDAC with a conversion speed of 10 GS/s demonstrates the feasibility of the proposed scheme. In addition, the performance degradation induced by the limited extinction ratios of the applied electro-optic modulators, the synchronization errors among different wavelength channels, and the bit resolutions of the built system is also discussed.

  8. 6beta,19-Bridged androstenedione analogs as aromatase inhibitors. (United States)

    Komatsu, Sachiko; Yaguchi, Ayaka; Yamashita, Kouwa; Nagaoka, Masao; Numazawa, Mitsuteru


    Inhibition of aromatase is an efficient approach for the prevention and treatment of breast cancer. New 6beta,19-bridged steroid analogs of androstenedione, 6beta,19-epithio- and 6beta,19-methano compounds 11 and 17, were synthesized starting from 19-hydroxyandrostenedione (6) and 19-formylandrost-5-ene-3beta,17beta-yl diacetate (12), respectively, as aromatase inhibitors. All of the compounds including known steroids 6beta,19-epoxyandrostenedione (4) and 6beta,19-cycloandrostenedione (5) tested were weak to poor competitive inhibitors of aromatase and, among them, 6beta,19-epoxy steroid 4 provided only moderate inhibition (K(i): 2.2 microM). These results show that the 6beta,19-bridged groups of the inhibitors interfere with binding in active site of aromatase.

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

    CERN Document Server

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


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

  10. Electronic Circuit Analog of Synthetic Genetic Networks: Revisited

    CERN Document Server

    Hellen, Edward H


    Electronic circuits are useful tools for studying potential dynamical behaviors of synthetic genetic networks. The circuit models are complementary to numerical simulations of the networks, especially providing a framework for verification of dynamical behaviors in the presence of intrinsic and extrinsic noise of the electrical systems. Here we present an improved version of our previous design of an electronic analog of genetic networks that includes the 3-gene Repressilator and we show conversions between model parameters and real circuit component values to mimic the numerical results in experiments. Important features of the circuit design include the incorporation of chemical kinetics representing Hill function inhibition, quorum sensing coupling, and additive noise. Especially, we make a circuit design for a systematic change of initial conditions in experiment, which is critically important for studies of dynamical systems' behavior, particularly, when it shows multistability. This improved electronic ...

  11. Evolution of Long Term Variability in Solar Analogs (United States)

    Egeland, Ricky; Soon, Willie; Baliunas, Sallie; Hall, Jeffrey C.; Henry, Gregory W.


    Earth is the only planet known to harbor life, therefore we may speculate on how the nature of the Sun-Earth interaction is relevant to life on Earth, and how the behavior of other stars may influence the development of life on their planetary systems. We study the long-term variability of a sample of five solar analog stars using composite chromospheric activity records up to 50 years in length and synoptic visible-band photometry about 20 years long. This sample covers a large range of stellar ages which we use to represent the evolution in activity for solar mass stars. We find that young, fast rotators have an amplitude of variability many times that of the solar cycle, while old, slow rotators have very little variability. We discuss the possible impacts of this variability on young Earth and exoplanet climates.

  12. Stabilized cyclopropane analogs of the splicing inhibitor FD-895. (United States)

    Villa, Reymundo; Kashyap, Manoj Kumar; Kumar, Deepak; Kipps, Thomas J; Castro, Januario E; La Clair, James J; Burkart, Michael D


    Targeting the spliceosome with small molecule inhibitors provides a new avenue to target cancer by intercepting alternate splicing pathways. Although our understanding of alternate mRNA splicing remains poorly understood, it provides an escape pathway for many cancers resistant to current therapeutics. These findings have encouraged recent academic and industrial efforts to develop natural product spliceosome inhibitors, including FD-895 (1a), pladienolide B (1b), and pladienolide D (1c), into next-generation anticancer drugs. The present study describes the application of semisynthesis and total synthesis to reveal key structure-activity relationships for the spliceosome inhibition by 1a. This information is applied to deliver new analogs with improved stability and potent activity at inhibiting splicing in patient derived cell lines.

  13. Mammary analog secretory carcinoma of thyroid: A case report. (United States)

    Rupp, Aaron P; Bocklage, Thèrése J


    Mammary analog secretory carcinoma (MASC) is a recently described rare neoplasm that was first reported in the salivary gland with an associated ETV6-NTRK3 fusion. We present a case of MASC involving and presumably arising in the thyroid, which was originally diagnosed as papillary thyroid carcinoma on fine needle aspiration and surgical resection. The later correct diagnosis of MASC was confirmed by immunohistochemistry and molecular studies. The cytopathological features of MASC in the salivary gland are previously described; however, we present the first cytopathological description of MASC arising in the thyroid with the unique feature of prominent nuclear grooves. Differentiating MASC from overlapping features of cytopathologic mimics such as papillary thyroid carcinoma may carry crucial therapeutic implications. Diagn. Cytopathol. 2017;45:45-50. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  14. Rheology of lava flows on Mercury: An analog experimental study (United States)

    Sehlke, A.; Whittington, A. G.


    We experimentally determined the rheological evolution of three basaltic analog compositions appropriate to Mercury's surface, during cooling, and crystallization. Investigated compositions are an enstatite basalt, and two magnesian basalts representing the compositional end-members of the northern volcanic plains with 0.19 wt % (NVP) and 6.26 wt % Na2O (NVP-Na). The viscosity-strain rate dependence of lava was quantified using concentric cylinder viscometry. We measured the viscosities of the crystal-free liquids from 1600°C down to the first detection of crystals. Liquidus temperatures of the three compositions studied are around 1360°C, and all three compositions are more viscous than Hawaiian basalt at the same temperature. The onset of pseudoplastic behavior was observed at crystal fractions ~0.05 to 0.10, which is consistent with previous studies on mafic lavas. We show that all lavas develop detectable yield strengths at crystal fractions around 0.20, beyond which the two-phase suspensions are better described as Herschel-Bulkley fluids. By analogy with the viscosity-strain rate conditions at which the pahoehoe to `a`a transition occurs in Kilauea basalt, this transition is predicted to occur at ~1260 ± 10°C for the enstatite basalt, at ~1285 ± 20°C for the NVP, and at ~1240 ± 40°C for the NVP-Na lavas. Our results indicate that Mercury lavas are broadly similar to terrestrial ones, which suggests that the extensive smooth lava plains of Mercury could be due to large effusion rates (flood basalts) and not to unusually fluid lavas.

  15. Analog memristive synapse in spiking networks implementing unsupervised learning

    Directory of Open Access Journals (Sweden)

    Erika Covi


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

  16. Military Importance of Natural Toxins and Their Analogs

    Directory of Open Access Journals (Sweden)

    Vladimír Pitschmann


    Full Text Available Toxin weapon research, development, production and the ban on its uses is an integral part of international law, with particular attention paid to the protection against these weapons. In spite of this, hazards associated with toxins cannot be completely excluded. Some of these hazards are also pointed out in the present review. The article deals with the characteristics and properties of natural toxins and synthetic analogs potentially constituting the basis of toxin weapons. It briefly describes the history of military research and the use of toxins from distant history up to the present age. With respect to effective disarmament conventions, it mentions certain contemporary concepts of possible toxin applications for military purposes and the protection of public order (suppression of riots; it also briefly refers to the question of terrorism. In addition, it deals with certain traditional as well as modern technologies of the research, synthesis, and use of toxins, which can affect the continuing development of toxin weapons. These are, for example, cases of new toxins from natural sources, their chemical synthesis, production of synthetic analogs, the possibility of using methods of genetic engineering and modern biotechnologies or the possible applications of nanotechnology and certain pharmaceutical methods for the effective transfer of toxins into the organism. The authors evaluate the military importance of toxins based on their comparison with traditional chemical warfare agents. They appeal to the ethics of the scientific work as a principal condition for the prevention of toxin abuse in wars, military conflicts, as well as in non-military attacks.

  17. Dimeric analogs of immunosuppressive decapeptide fragment of ubiquitin. (United States)

    Kluczyk, Alicja; Cydzik, Marzena; Biernat, Monika; Bąchor, Remigiusz; Pasikowski, Paweł; Stefanowicz, Piotr; Artym, Jolanta; Zimecki, Michał; Szewczuk, Zbigniew


    Our previous studies revealed that ubiquitin and its decapeptide fragment with the LEDGRTLSDY sequence, located on the exposed molecule loop, strongly suppressed the immune response. This suggested that the loop may serve as a functional epitope of ubiquitin molecule and that a possible mechanism of biological action of the synthesized peptides is associated with interfering in interactions of ubiquitin with other molecules. Ubiquitin is known to exist in oligomeric forms, which can interact with various oligomeric receptors. We designed and synthesized new dimeric analogs of the ubiquitin fragment, to probe whether dimeric peptides may have higher affinity towards the ubiquitin receptors responsible for immunosuppression, which are believed to form oligomeric structures. Three dimerization strategies, N-terminus to N-terminus, C-terminus to C-terminus, and N-terminus to C-terminus (head-to-tail) via PEG derivatives were used to synthesize the dimeric peptides on solid support. In the course of our research, we developed a new and straightforward procedure of dimerization where α-amino groups of the C-terminal lysine residues of two peptide fragments were linked by PEG spacer directly on solid support. The effect of dimeric analogs on the immunological response was tested in the AFC in vitro experiment. The immunological tests showed that the head-to-tail dimerization caused a more profound increase in the biological activity than other tested dimerization methods. Our results suggest that such orientation of peptide components may correspond to orientation of the hypothetic ubiquitin receptors responsible for the immunomodulatory activity. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

  18. Mrk 71/NGC 2366: The Nearest Green Pea Analog

    Energy Technology Data Exchange (ETDEWEB)

    Micheva, Genoveva; Oey, M. S. [University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109-1107 (United States); Jaskot, Anne E. [Department of Astronomy, Smith College, Northampton, MA 01063 (United States); James, Bethan L. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States)


    We present the remarkable discovery that the dwarf irregular galaxy NGC 2366 is an excellent analog of the Green Pea (GP) galaxies, which are characterized by extremely high ionization parameters. The similarities are driven predominantly by the giant H ii region Markarian 71 (Mrk 71). We compare the system with GPs in terms of morphology, excitation properties, specific star-formation rate, kinematics, absorption of low-ionization species, reddening, and chemical abundance, and find consistencies throughout. Since extreme GPs are associated with both candidate and confirmed Lyman continuum (LyC) emitters, Mrk 71/NGC 2366 is thus also a good candidate for LyC escape. The spatially resolved data for this object show a superbubble blowout generated by mechanical feedback from one of its two super star clusters (SSCs), Knot B, while the extreme ionization properties are driven by the ≲1 Myr-old, enshrouded SSC Knot A, which has ∼10 times higher ionizing luminosity. Very massive stars (>100 M {sub ⊙}) may be present in this remarkable object. Ionization-parameter mapping indicates that the blowout region is optically thin in the LyC, and the general properties also suggest LyC escape in the line of sight. Mrk 71/NGC 2366 does differ from GPs in that it is one to two orders of magnitude less luminous. The presence of this faint GP analog and candidate LyC emitter (LCE) so close to us suggests that LCEs may be numerous and commonplace, and therefore could significantly contribute to the cosmic ionizing budget. Mrk 71/NGC 2366 offers an unprecedentedly detailed look at the viscera of a candidate LCE, and could clarify the mechanisms of LyC escape.

  19. 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...

  20. Beuchot’s formal analogism within Peter Singer’s philosophy

    Directory of Open Access Journals (Sweden)

    José Barrientos-Rastrojo


    Full Text Available This paper analyses an analogic reading of singerian ethics. Firstly, it studies Mauricio Beuchot’s analogical hermeneutics grounds. Then, it takes them to each of the Peter Singer’s ethical universes. Finally, it reveals the scheme of his ethic that will be followed in his future works. Therefore, this article has a prospective mission related to Professor Singer and it has an practical mission related to Mauricio Beuchot because it determines a practical performance to his analogical hermeneutics.


    Directory of Open Access Journals (Sweden)

    Rahayu Kariadinata


    Full Text Available Learning mathematical analogy is one alternative learning that can be applied in order to cultivate the power of reason (power of reason students. Through mathematical analogy students are required to be able to look for similarities or relationship nature of the two concepts are the same or different by comparison, then draw a conclusion from the similitude. Thus the analogy can be used as an explanation or as the basis of reasoning. Before starting the analogy of learning mathematics, teachers should examine the ability of understanding mathematical concepts of students, because of the level of understanding of students will affect the power of reason. Tasks (problems mathematical analogy included non-routine matter, therefore the required readiness of teachers to make it. In each question contained mathematical analogy same or different concepts, so it takes quite a lot of material. Steps to make about the mathematical analogy, are: a assemble all the concepts in mathematics student has learned; b Similarly stacking properties / relationships contained in any concept, and c select materials that have a nature / relationship analogous. In this paper is given two forms of matter of mathematical analogy is the analogy of mathematical models and mathematical analogy 1 models 2. Learning mathematical analogy should be carried out after a number of concepts learned. It is better to be given in classes end for many of the concepts that have been learned by the students. Reasoning power (power of reason the student becomes an important part in the process of learning to drive them toward their future as citizens are intelligent, which will be led by the power of reason (the brain and not by the strength (muscle only. As noted by former US President Thomas Jefferson (in Copi, 1978: vii, which states: "In a republican nation, Whose citizens are to be led by reason and persuasion and not by force, the art of reasoning Becomes of first importance"

  2. Auxin transport sites are visualized in planta using fluorescent auxin analogs


    Hayashi, Ken-ichiro; Nakamura, Shouichi; Fukunaga(Ubukata), Shiho; Nishimura, Takeshi; Jenness, Mark K.; Murphy, Angus S.; Motose, Hiroyasu; Nozaki, Hiroshi; Furutani, Masahiko; Aoyama, Takashi


    Fluorescent auxin analogs are designed to function as active auxins for the auxin transport system but to be inactive for auxin signaling. These fluorescent auxin analogs can mimic auxin via the transport system and be used to visualize inter- and intracellular auxin distribution in roots. These analogs allow imaging of auxin transport sites with high spatiotemporal resolution. Our fluorescent auxin system provides insight into auxin transport dynamics and subcellular auxin distribution.

  3. A review on the chemical synthesis of pyrophosphate bonds in bioactive nucleoside diphosphate analogs. (United States)

    Xu, Zhihong


    Currently, there is an ongoing interest in the synthesis of nucleoside diphosphate analogs as important regulators in catabolism/anabolism, and their potential applications as mechanistic probes and chemical tools for bioassays. However, the pyrophosphate bond formation step remains as the bottleneck. In this Digest, the chemical synthesis of the pyrophosphate bonds of representative bioactive nucleoside diphosphate analogs, i.e. phosphorus-modified analogs, nucleoside cyclic diphosphates, and nucleoside diphosphate conjugates, will be described. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Fluid Intelligence Allows Flexible Recruitment of the Parieto-Frontal Network in Analogical Reasoning


    Preusse, Franziska; Elke, van der Meer; Deshpande, Gopikrishna; Krueger, Frank; Wartenburger, Isabell


    Fluid intelligence is the ability to think flexibly and to understand abstract relations. People with high fluid intelligence (hi-fluIQ) perform better in analogical reasoning tasks than people with average fluid intelligence (ave-fluIQ). Although previous neuroimaging studies reported involvement of parietal and frontal brain regions in geometric analogical reasoning (which is a prototypical task for fluid intelligence), however, neuroimaging findings on geometric analogical reasoning in hi-...

  5. Inhibiting Effects of Lunularic Acid Analogs on the Growth of Liverwort, Watercress, and Timothy Grass. (United States)

    Nakayama, T; Fukushi, Y; Mizutani, J; Tahara, S


    A number of analogs of lunularic acid varying in the number of methylene carbons between the two benzene rings and in the substituents on their rings were prepared, and their effects on the growth of liverwort gemmaling, watercress, and timothy grass were investigated. Almost all the analogs tested were more inhibitory than lunularic acid, and a correlation between the structure and activity was observed. The differences in the growth-inhibition activity of analogs between higher and lower plants are also discussed.

  6. 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.

  7. Synthesis and antiretroviral activity of novel 4'-fluoro-5'-deoxyphosphonic acid carbocyclic nucleoside analogs. (United States)

    Kim, Eunae; Kim, Seyeon; Hong, Joon Hee


    Novel 5'-deoxycarbocyclic purine phosphonic acid analogs with the 4'-electropositive moiety, fluorine were designed, and synthesized from glyceraldehyde. The cyclopentenol intermediate, 9, was successfully synthesized by the ring-closing metathesis of divinyl 8. The condensation reaction of cyclopentanol 15 with purine bases under Mitsunobu conditions successfully afforded the desired phosphonate analogs. The synthesized nucleoside phosphonic acid analogs, 19, 22, 26, and 29, were subjected to antiviral screening against human immunodeficiency virus (HIV)-1. Guanine phosphonic acid analog 29 showed significant anti-HIV activity (EC50 = 10.3 μM).

  8. Insights into structure-activity relationships of somatostatin analogs containing mesitylalanine

    National Research Council Canada - National Science Library

    Martín-Gago, Pablo; Aragón, Eric; Gomez-Caminals, Marc; Fernández-Carneado, Jimena; Ramón, Rosario; Martin-Malpartida, Pau; Verdaguer, Xavier; López-Ruiz, Pilar; Colás, Begoña; Cortes, María Alicia; Ponsati, Berta; Macias, Maria J; Riera, Antoni


    .... Taking these properties into account, we have synthesized ten somatostatin analogs containing Msa residues in different key positions to modify the intrinsic conformational flexibility of the natural hormone...

  9. Nano-scale CMOS analog circuits models and CAD techniques for high-level design

    CERN Document Server

    Pandit, Soumya; Patra, Amit


    Reliability concerns and the limitations of process technology can sometimes restrict the innovation process involved in designing nano-scale analog circuits. The success of nano-scale analog circuit design requires repeat experimentation, correct analysis of the device physics, process technology, and adequate use of the knowledge database.Starting with the basics, Nano-Scale CMOS Analog Circuits: Models and CAD Techniques for High-Level Design introduces the essential fundamental concepts for designing analog circuits with optimal performances. This book explains the links between the physic

  10. Exploring the use of multiple analogical models when teaching and learning chemical equilibrium (United States)

    Harrison, Allan G.; de Jong, Onno


    This study describes the multiple analogical models used to introduce and teach Grade 12 chemical equilibrium. We examine the teacher's reasons for using models, explain each model's development during the lessons, and analyze the understandings students derived from the models. A case study approach was used and the data were drawn from the observation of three consecutive Grade 12 lessons on chemical equilibrium, pre- and post-lesson interviews, and delayed student interviews. The key analogical models used in teaching were: the school dance; the sugar in a teacup; the pot of curry; and the busy highway. The lesson and interview data were subject to multiple, independent analyses and yielded the following outcomes: The teacher planned to use the students' prior knowledge wherever possible and he responded to student questions with stories and extended and enriched analogies. He planned to discuss where each analogy broke down but did not. The students enjoyed the teaching but built variable mental models of equilibrium and some of their analogical mappings were unreliable. A female student disliked masculine analogies, other students tended to see elements of the multiple models in isolation, and some did not recognize all the analogical mappings embedded in the teaching plan. Most students learned that equilibrium reactions are dynamic, occur in closed systems, and the forward and reverse reactions are balanced. We recommend the use of multiple analogies like these and insist that teachers always show where the analogy breaks down and carefully negotiate the conceptual outcomes.

  11. Advances in analog and RF IC design for wireless communication systems

    CERN Document Server

    Manganaro, Gabriele


    Advances in Analog and RF IC Design for Wireless Communication Systems gives technical introductions to the latest and most significant topics in the area of circuit design of analog/RF ICs for wireless communication systems, emphasizing wireless infrastructure rather than handsets. The book ranges from very high performance circuits for complex wireless infrastructure systems to selected highly integrated systems for handsets and mobile devices. Coverage includes power amplifiers, low-noise amplifiers, modulators, analog-to-digital converters (ADCs) and digital-to-analog converters

  12. Maitotoxin-4, a Novel MTX Analog Produced by Gambierdiscus excentricus

    Directory of Open Access Journals (Sweden)

    Francesco Pisapia


    Full Text Available Maitotoxins (MTXs are among the most potent toxins known. These toxins are produced by epi-benthic dinoflagellates of the genera Gambierdiscus and Fukuyoa and may play a role in causing the symptoms associated with Ciguatera Fish Poisoning. A recent survey revealed that, of the species tested, the newly described species from the Canary Islands, G. excentricus, is one of the most maitotoxic. The goal of the present study was to characterize MTX-related compounds produced by this species. Initially, lysates of cells from two Canary Island G. excentricus strains VGO791 and VGO792 were partially purified by (i liquid-liquid partitioning between dichloromethane and aqueous methanol followed by (ii size-exclusion chromatography. Fractions from chromatographic separation were screened for MTX toxicity using both the neuroblastoma neuro-2a (N2a cytotoxicity and Ca2+ flux functional assays. Fractions containing MTX activity were analyzed using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS to pinpoint potential MTX analogs. Subsequent non-targeted HRMS analysis permitted the identification of a novel MTX analog, maitotoxin-4 (MTX4, accurate mono-isotopic mass of 3292.4860 Da, as free acid form in the most toxic fractions. HRMS/MS spectra of MTX4 as well as of MTX are presented. In addition, crude methanolic extracts of five other strains of G. excentricus and 37 other strains representing one Fukuyoa species and ten species, one ribotype and one undetermined strain/species of Gambierdiscus were screened for the presence of MTXs using low resolution tandem mass spectrometry (LRMS/MS. This targeted analysis indicated the original maitotoxin (MTX was only present in one strain (G. australes S080911_1. Putative maitotoxin-2 (p-MTX2 and maitotoxin-3 (p-MTX3 were identified in several other species, but confirmation was not possible because of the lack of reference material. Maitotoxin-4 was detected in all seven strains of G

  13. Plume capture by a migrating ridge: Analog geodynamic experiments (United States)

    Mendez, J. S.; Hall, P.


    Paleomagnetic data from the Hawaii-Emperor Seamount Chain (HESC) suggests that the Hawaiian hotspot moved rapidly (~40 mm/yr) between 81 - 47 Ma but has remained relatively stationary since that time. This implies that the iconic bend in the HESC may in fact reflect the transition from a period of rapid hotspot motion to a stationary state, rather than a change in motion of the Pacific plate. Tarduno et al. (2009) have suggested that this period of rapid hotspot motion might be the surface expression of a plume conduit returning to a largely vertical orientation after having been “captured” and tilted by a migrating mid-ocean ridge. We report on a series of analog fluid dynamic experiments designed to characterize the interaction between a migrating spreading center and a thermally buoyant mantle plume. Experiments were conducted in a clear acrylic tank (100 cm x 70 cm x 50 cm) filled with commercial grade high-fructose corn syrup. Plate-driven flow is modeled by dragging two sheets of Mylar film (driven by independent DC motors) in opposite directions over the surface of the fluid. Ridge migration is achieved by moving the point at which the mylar sheets diverge using a separate motor drive. Buoyant plume flow is modeled using corn syrup introduced into the bottom of the tank from an external, heated, pressurized reservoir. Small (~2 mm diameter), neutrally buoyant Delrin spheres are mixed into reservoir of plume material to aid in visualization. Plate velocities and ridge migration rate are controlled and plume temperature monitored using LabView software. Experiments are recorded using digital video which is then analyzed using digital image analysis software to track the position and shape of the plume conduit throughout the course of the experiment. The intersection of the plume conduit with the surface of the fluid is taken as an analog for the locus of hotspot volcanism and tracked as a function of time to obtain a hotspot migration rate. Experiments are

  14. Subcritical water extraction of amino acids from Mars analog soils. (United States)

    Noell, Aaron C; Fisher, Anita M; Fors-Francis, Kisa; Sherrit, Stewart


    For decades, the Martian regolith has stymied robotic mission efforts to catalog the organic molecules present. Perchlorate salts, found widely throughout Mars, are the main culprit as they breakdown and react with organics liberated from the regolith during pyrolysis, the primary extraction technique attempted to date on Mars. This work further develops subcritical water extraction (SCWE) as a technique for extraction of amino acids on future missions. The effect of SCWE temperature (185, 200, and 215°C) and duration of extraction (10-120 min) on the total amount and distribution of amino acids recovered was explored for three Mars analog soils (JSC Mars-1A simulant, an Atacama desert soil, and an Antarctic Dry Valleys soil) and bovine serum albumin (as a control solution of known amino acid content). Total amounts of amino acids extracted increased with both time and temperature; however, the distribution shifted notably due to the destruction of the amino acids with charged or polar side chains at the higher temperatures. The pure bovine serum albumin solution and JSC Mars 1A also showed lower yields than the Atacama and Antarctic extractions suggesting that SCWE may be less effective at hydrolyzing large or aggregated proteins. Changing solvent from water to a dilute (10 mM) HCl solution allowed total extraction efficiencies comparable to the higher temperature/time combinations while using the lowest temperature/time (185°C/20 min). The dilute HCl extractions also did not lead to the shift in amino acid distribution observed at the higher temperatures. Additionally, adding sodium perchlorate salt to the extraction did not interfere with recoveries. Native magnetite in the JSC Mars-1A may have been responsible for destruction of glycine, as evidenced by its uncharacteristic decrease as the temperature/time of extraction increased. This work shows that SCWE can extract high yields of native amino acids out of Mars analog soils with minimal disruption of the

  15. Neural correlates of intelligence as revealed by fMRI of fluid analogies. (United States)

    Geake, John G; Hansen, Peter C


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

  16. Antibacterial Nucleoside-Analog Inhibitor of Bacterial RNA Polymerase. (United States)

    Maffioli, Sonia I; Zhang, Yu; Degen, David; Carzaniga, Thomas; Del Gatto, Giancarlo; Serina, Stefania; Monciardini, Paolo; Mazzetti, Carlo; Guglierame, Paola; Candiani, Gianpaolo; Chiriac, Alina Iulia; Facchetti, Giuseppe; Kaltofen, Petra; Sahl, Hans-Georg; Dehò, Gianni; Donadio, Stefano; Ebright, Richard H


    Drug-resistant bacterial pathogens pose an urgent public-health crisis. Here, we report the discovery, from microbial-extract screening, of a nucleoside-analog inhibitor that inhibits bacterial RNA polymerase (RNAP) and exhibits antibacterial activity against drug-resistant bacterial pathogens: pseudouridimycin (PUM). PUM is a natural product comprising a formamidinylated, N-hydroxylated Gly-Gln dipeptide conjugated to 6'-amino-pseudouridine. PUM potently and selectively inhibits bacterial RNAP in vitro, inhibits bacterial growth in culture, and clears infection in a mouse model of Streptococcus pyogenes peritonitis. PUM inhibits RNAP through a binding site on RNAP (the NTP addition site) and mechanism (competition with UTP for occupancy of the NTP addition site) that differ from those of the RNAP inhibitor and current antibacterial drug rifampin (Rif). PUM exhibits additive antibacterial activity when co-administered with Rif, exhibits no cross-resistance with Rif, and exhibits a spontaneous resistance rate an order-of-magnitude lower than that of Rif. PUM is a highly promising lead for antibacterial therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. 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.

  18. Observations of Crew Dynamics during Mars Analog Simulations (United States)

    Cusack, Stacy L.


    This presentation reviews the crew dynamics during two simulations of Mars Missions. Using an analog of a Mars habitat in two locations, Flashline Mars Arctic Research Station (FMARS) which is located on Devon Island at 75 deg North in the Canadian Arctic, and the Mars Desert Research Station (MDRS) which is located in the south of Utah, the presentation examines the crew dynamics in relation to the leadership style of the commander of the mission. The difference in the interaction of the two crews were shown to be related to the leadership style and the age group in the crew. As much as possible the habitats and environment was to resemble a Mars outpost. The difference between the International Space Station and a Mars missions is reviewed. The leadership styles are reviewed and the contrast between the FMARS and the MDRS leadership styles were related to crew productivity, and the personal interactions between the crew members. It became evident that leadership styles and interpersonal skill had more affect on mission success and crew dynamics than other characteristics.

  19. Serial pixel analog-to-digital converter (ADC) (United States)

    Larson, Eric D.


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

  20. Construction and commissioning of the CALICA analog hadron calorimeter prototype

    Energy Technology Data Exchange (ETDEWEB)

    Adloff, C.; Karyotakis, Y. [Universite de Savoie, Annecy-le-Vieux (France). Laboratoire d' Annecy-le-Vieux de Physique des Particules, CNRS/IN2P3; Repond, J. [Argonne National Laboratory, Argonne, IL (US)] (and others)


    An analog hadron calorimeter (AHCAL) prototype of 5.3 nuclear interaction lengths thickness has been constructed by members of the CALICE Collaboration. The AHCAL prototype consists of a 38-layer sandwich structure of steel plates and highlysegmented scintillator tiles that are read out by wavelength-shifting fibers coupled to SiPMs. The signal is amplified and shaped with a custom-designed ASIC. A calibration/ monitoring system based on LED light was developed to monitor the SiPM gain and to measure the full SiPM response curve in order to correct for non-linearity. Ultimately, the physics goals are the study of hadron shower shapes and testing the concept of particle flow. The technical goal consists of measuring the performance and reliability of 7608 SiPMs. The AHCAL was commissioned in test beams at DESY and CERN. The entire prototype was completed in 2007 and recorded hadron showers, electron showers and muons at different energies and incident angles in test beams at CERN and Fermilab. (orig.)