WorldWideScience

Sample records for fully integrated clock

  1. A fully integral, differential, high-speed, low-power consumption CMOS recovery clock circuit

    Directory of Open Access Journals (Sweden)

    Daniel Pacheco Bautista

    2007-09-01

    Full Text Available The clock recovery circuit (CRC plays a fundamental role in electronic information recovery systems (hard disks, DVD and CD read/writeable units and baseband digital communication systems in recovering the clock signal contained in the received data. This signal is necessary for synchronising subsequent information processing. Nowadays, this task is difficult to achieve because of the data’s random nature and its high transfer rate. This paper presents the design of a high-performance integral CMOS technology clock recovery circuit (CRC wor-king at 1.2 Gbps and only consuming 17.4 mW using a 3.3V power supply. The circuit was fully differentially designed to obtain high performance. Circuit architecture was based on a conventional phase lock loop (PLL, current mode logic (MCML and a novel two stage ring-based voltage controlled oscillator (VCO. The design used 0.35 μm CMOS AMS process parameters. Hspice simulation results proved the circuit’s high performance, achieving tracking in less than 300 ns.

  2. Integration of biological clocks and rhythms.

    Science.gov (United States)

    Refinetti, Roberto

    2012-04-01

    Animals, plants, and microorganisms exhibit numerous biological rhythms that are generated by numerous biological clocks. This article summarizes experimental data pertinent to the often-ignored issue of integration of multiple rhythms. Five contexts of integration are discussed: (i) integration of circadian rhythms of multiple processes within an individual organism, (ii) integration of biological rhythms operating in different time scales (such as tidal, daily, and seasonal), (iii) integration of rhythms across multiple species, (iv) integration of rhythms of different members of a species, and (v) integration of rhythmicity and physiological homeostasis. Understanding of these multiple rhythmic interactions is an important first step in the eventual thorough understanding of how organisms arrange their vital functions temporally within and without their bodies. © 2012 American Physiological Society. Compr Physiol 2:1213-1239, 2012.

  3. A fully reconfigurable photonic integrated signal processor

    Science.gov (United States)

    Liu, Weilin; Li, Ming; Guzzon, Robert S.; Norberg, Erik J.; Parker, John S.; Lu, Mingzhi; Coldren, Larry A.; Yao, Jianping

    2016-03-01

    Photonic signal processing has been considered a solution to overcome the inherent electronic speed limitations. Over the past few years, an impressive range of photonic integrated signal processors have been proposed, but they usually offer limited reconfigurability, a feature highly needed for the implementation of large-scale general-purpose photonic signal processors. Here, we report and experimentally demonstrate a fully reconfigurable photonic integrated signal processor based on an InP-InGaAsP material system. The proposed photonic signal processor is capable of performing reconfigurable signal processing functions including temporal integration, temporal differentiation and Hilbert transformation. The reconfigurability is achieved by controlling the injection currents to the active components of the signal processor. Our demonstration suggests great potential for chip-scale fully programmable all-optical signal processing.

  4. Fully Integral, Flexible Composite Driveshaft, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — An all-composite driveshaft incorporating integral flexible diaphragms is described and proposed for phase II prime conractor testing. The approach obsoletes the...

  5. Fully Integral, Flexible Composite Driveshaft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An all-composite driveshaft incorporating integral flexible diaphragms is described and proposed for further refinement. An approach is explored which obsoletes the...

  6. Molecular clock integration of brown adipose tissue formation and function

    OpenAIRE

    Nam, Deokhwa; Yechoor, Vijay K.; Ma, Ke

    2015-01-01

    Abstract The circadian clock is an essential time-keeping mechanism that entrains internal physiology to environmental cues. Despite the well-established link between the molecular clock and metabolic homeostasis, an intimate interplay between the clock machinery and the metabolically active brown adipose tissue (BAT) is only emerging. Recently, we came to appreciate that the formation and metabolic functions of BAT, a key organ for body temperature maintenance, are under an orchestrated circ...

  7. Molecular clock integration of brown adipose tissue formation and function.

    Science.gov (United States)

    Nam, Deokhwa; Yechoor, Vijay K; Ma, Ke

    2016-01-01

    The circadian clock is an essential time-keeping mechanism that entrains internal physiology to environmental cues. Despite the well-established link between the molecular clock and metabolic homeostasis, an intimate interplay between the clock machinery and the metabolically active brown adipose tissue (BAT) is only emerging. Recently, we came to appreciate that the formation and metabolic functions of BAT, a key organ for body temperature maintenance, are under an orchestrated circadian clock regulation. Two complementary studies from our group uncover that the cell-intrinsic clock machinery exerts concerted control of brown adipogenesis with consequent impacts on adaptive thermogenesis, which adds a previously unappreciated temporal dimension to the regulatory mechanisms governing BAT development and function. The essential clock transcriptional activator, Bmal1, suppresses adipocyte lineage commitment and differentiation, whereas the clock repressor, Rev-erbα, promotes these processes. This newly discovered temporal mechanism in fine-tuning BAT thermogenic capacity may enable energy utilization and body temperature regulation in accordance with external timing signals during development and functional recruitment. Given the important role of BAT in whole-body metabolic homeostasis, pharmacological interventions targeting the BAT-modulatory activities of the clock circuit may offer new avenues for the prevention and treatment of metabolic disorders, particularly those associated with circadian dysregulation.

  8. A Scalable, Timing-Safe, Network-on-Chip Architecture with an Integrated Clock Distribution Method

    DEFF Research Database (Denmark)

    Bjerregaard, Tobias; Stensgaard, Mikkel Bystrup; Sparsø, Jens

    2007-01-01

    regions concerns the possibility of data corruption caused by metastability. This paper presents an integrated communication and mesochronous clocking strategy, which avoids timing related errors while maintaining a globally synchronous system perspective. The architecture is scalable as timing integrity......Growing system sizes together with increasing performance variability are making globally synchronous operation hard to realize. Mesochronous clocking constitutes a possible solution to the problems faced. The most fundamental of problems faced when communicating between mesochronously clocked...... is based purely on local observations. It is demonstrated with a 90 nm CMOS standard cell network-on-chip design which implements completely timing-safe, global communication in a modular system...

  9. Method and apparatus to debug an integrated circuit chip via synchronous clock stop and scan

    Science.gov (United States)

    Bellofatto, Ralph E [Ridgefield, CT; Ellavsky, Matthew R [Rochester, MN; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Gooding, Thomas M [Rochester, MN; Haring, Rudolf A [Cortlandt Manor, NY; Hehenberger, Lance G [Leander, TX; Ohmacht, Martin [Yorktown Heights, NY

    2012-03-20

    An apparatus and method for evaluating a state of an electronic or integrated circuit (IC), each IC including one or more processor elements for controlling operations of IC sub-units, and each the IC supporting multiple frequency clock domains. The method comprises: generating a synchronized set of enable signals in correspondence with one or more IC sub-units for starting operation of one or more IC sub-units according to a determined timing configuration; counting, in response to one signal of the synchronized set of enable signals, a number of main processor IC clock cycles; and, upon attaining a desired clock cycle number, generating a stop signal for each unique frequency clock domain to synchronously stop a functional clock for each respective frequency clock domain; and, upon synchronously stopping all on-chip functional clocks on all frequency clock domains in a deterministic fashion, scanning out data values at a desired IC chip state. The apparatus and methodology enables construction of a cycle-by-cycle view of any part of the state of a running IC chip, using a combination of on-chip circuitry and software.

  10. A fully integrated 16 channel digitally trimmed pulse shaping amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Hearn, W.E.; Wright, M.E.

    1993-11-01

    A fully integrated CMOS pulse shaping amplifier has been developed at LBL. All frequency dependent networks are included on the chip. Provision is made for tuning to compensate for process variations. The overall architecture and details of the circuitry are discussed. Test results are presented.

  11. A fully integrated 16 channel digitally trimmed pulse shaping amplifier

    International Nuclear Information System (INIS)

    Hearn, W.E.; Wright, M.E.

    1993-11-01

    A fully integrated CMOS pulse shaping amplifier has been developed at LBL. All frequency dependent networks are included on the chip. Provision is made for tuning to compensate for process variations. The overall architecture and details of the circuitry are discussed. Test results are presented

  12. 5 ten volle geïntegreerde woordeboeke / Fully Integrated ...

    African Journals Online (AJOL)

    rbr

    Lexikos 11 (AFRILEX-reeks/series 11: 2001): 324-327. Pharos. Pharos Woordeboeke / Dictionaries 5 in 1: 5 ten volle geïntegreerde woordeboeke / Fully Integrated Dictionaries. Afrikaans-Engels / English-. Afrikaans 1. Groot Woordeboek / Major Dictionary 2. Tweetalige Frasewoor- deboek / Bilingual Phrase Dictionary 3.

  13. Electronically Tunable Fully Integrated Fractional-Order Resonator

    KAUST Repository

    Tsirimokou, Georgia

    2017-03-20

    A fully integrated implementation of a parallel fractional-order resonator which employs together a fractional order capacitor and a fractional-order inductor is proposed in this paper. The design utilizes current-controlled Operational Transconductance Amplifiers as building blocks, designed and fabricated in AMS 0:35m CMOS process, and based on a second-order approximation of a fractional-order differentiator/ integrator magnitude optimized in the range 10Hz–700Hz. An attractive benefit of the proposed scheme is its electronic tuning capability.

  14. Fully integrated digital GAMMA camera-computer system

    International Nuclear Information System (INIS)

    Berger, H.J.; Eisner, R.L.; Gober, A.; Plankey, M.; Fajman, W.

    1985-01-01

    Although most of the new non-nuclear imaging techniques are fully digital, there has been a reluctance in nuclear medicine to abandon traditional analog planar imaging in favor of digital acquisition and display. The authors evaluated a prototype digital camera system (GE STARCAM) in which all of the analog acquisition components are replaced by microprocessor controls and digital circuitry. To compare the relative effects of acquisition matrix size on image quality and to ascertain whether digital techniques could be used in place of analog imaging, Tc-99m bone scans were obtained on this digital system and on a comparable analog camera in 10 patients. The dedicated computer is used for camera setup including definition of the energy window, spatial energy correction, and spatial distortion correction. The display monitor, which is used for patient positioning and image analysis, is 512/sup 2/ non-interlaced, allowing high resolution imaging. Data acquisition and processing can be performed simultaneously. Thus, the development of a fully integrated digital camera-computer system with optimized display should allow routine utilization of non-analog studies in nuclear medicine and the ultimate establishment of fully digital nuclear imaging laboratories

  15. Status of fully integrated GaAs particle detectors

    International Nuclear Information System (INIS)

    Braunschweig, W.; Breibach, J.; Kubicki, Th.; Luebelsmeyer, K.; Maesing, Th.; Rente, C.; Roeper, Ch.; Siemes, A.

    1999-01-01

    GaAs strip detectors are of interest because of their radiation hardness at room temperature and the high absorption coefficient of GaAs for x-rays. The detectors currently under development will be used in the VLQ-experiment at the H1 experiment at the HERA collider. This will be the first high energy physics experiment where GaAs detectors will be used. The detectors have a sensitive area of 5 x 4 cm with a pitch of 62 μ m. Due to the high density of channels the biasing resistors and coupling capacitors are integrated. For the resistors a resistive layer made of Cermet is used. The properties of the first fully integrated strip detector are presented

  16. Fully integrated circuit chip of microelectronic neural bridge

    Science.gov (United States)

    Xiaoyan, Shen; Zhigong, Wang

    2014-09-01

    Nerve tracts interruption is one of the major reasons for dysfunction after spiral cord injury. The microelectronic neural bridge is a method to restore function of interrupted neural pathways, by making use of microelectronic chips to bypass the injured nerve tracts. A low-power fully integrated microelectronic neural bridge chip is designed, using CSMC 0.5-μm CMOS technology. The structure and the key points in the circuit design will be introduced in detail. In order to meet the requirement for implantation, the circuit was modified to avoid the use of off-chip components, and fully monolithic integration is achieved. The operating voltage of the circuit is ±2.5 V, and the chip area is 1.21 × 1.18 mm2. According to the characteristic of neural signal, the time-domain method is used in testing. The pass bandwidth of the microelectronic neural bridge system covers the whole frequency range of the neural signal, power consumption is 4.33 mW, and the gain is adjustable. The design goals are achieved.

  17. A fully integrated standalone portable cavity ringdown breath acetone analyzer.

    Science.gov (United States)

    Sun, Meixiu; Jiang, Chenyu; Gong, Zhiyong; Zhao, Xiaomeng; Chen, Zhuying; Wang, Zhennan; Kang, Meiling; Li, Yingxin; Wang, Chuji

    2015-09-01

    Breath analysis is a promising new technique for nonintrusive disease diagnosis and metabolic status monitoring. One challenging issue in using a breath biomarker for potential particular disease screening is to find a quantitative relationship between the concentration of the breath biomarker and clinical diagnostic parameters of the specific disease. In order to address this issue, we need a new instrument that is capable of conducting real-time, online breath analysis with high data throughput, so that a large scale of clinical test (more subjects) can be achieved in a short period of time. In this work, we report a fully integrated, standalone, portable analyzer based on the cavity ringdown spectroscopy technique for near-real time, online breath acetone measurements. The performance of the portable analyzer in measurements of breath acetone was interrogated and validated by using the certificated gas chromatography-mass spectrometry. The results show that this new analyzer is useful for reliable online (online introduction of a breath sample without pre-treatment) breath acetone analysis with high sensitivity (57 ppb) and high data throughput (one data per second). Subsequently, the validated breath analyzer was employed for acetone measurements in 119 human subjects under various situations. The instrument design, packaging, specifications, and future improvements were also described. From an optical ringdown cavity operated by the lab-set electronics reported previously to this fully integrated standalone new instrument, we have enabled a new scientific tool suited for large scales of breath acetone analysis and created an instrument platform that can even be adopted for study of other breath biomarkers by using different lasers and ringdown mirrors covering corresponding spectral fingerprints.

  18. A fully integrated standalone portable cavity ringdown breath acetone analyzer

    Science.gov (United States)

    Sun, Meixiu; Jiang, Chenyu; Gong, Zhiyong; Zhao, Xiaomeng; Chen, Zhuying; Wang, Zhennan; Kang, Meiling; Li, Yingxin; Wang, Chuji

    2015-09-01

    Breath analysis is a promising new technique for nonintrusive disease diagnosis and metabolic status monitoring. One challenging issue in using a breath biomarker for potential particular disease screening is to find a quantitative relationship between the concentration of the breath biomarker and clinical diagnostic parameters of the specific disease. In order to address this issue, we need a new instrument that is capable of conducting real-time, online breath analysis with high data throughput, so that a large scale of clinical test (more subjects) can be achieved in a short period of time. In this work, we report a fully integrated, standalone, portable analyzer based on the cavity ringdown spectroscopy technique for near-real time, online breath acetone measurements. The performance of the portable analyzer in measurements of breath acetone was interrogated and validated by using the certificated gas chromatography-mass spectrometry. The results show that this new analyzer is useful for reliable online (online introduction of a breath sample without pre-treatment) breath acetone analysis with high sensitivity (57 ppb) and high data throughput (one data per second). Subsequently, the validated breath analyzer was employed for acetone measurements in 119 human subjects under various situations. The instrument design, packaging, specifications, and future improvements were also described. From an optical ringdown cavity operated by the lab-set electronics reported previously to this fully integrated standalone new instrument, we have enabled a new scientific tool suited for large scales of breath acetone analysis and created an instrument platform that can even be adopted for study of other breath biomarkers by using different lasers and ringdown mirrors covering corresponding spectral fingerprints.

  19. SOFI, a symptom-oriented, fully integrated emergency operating procedure

    International Nuclear Information System (INIS)

    Knobel, R.C.

    1987-01-01

    This paper builds on a previous look at decision-tree emergency operating procedures to describe the symptom-oriented fully integrated (SOFI) process and what has been accomplished. The SOFI emergency operating procedures process results in one emergency operation procedure, thus eliminating the confusion and resultant jumping into and out of the wrong procedure (or the right ones if the operator misdiagnoses the event combination). The SOFI process results in emergency operating procedures that have a simple single-entry condition. The SOFI process results in emergency operating procedures that, once entered, require the operator to, by evaluating symptoms, determine the state of the plant and then provide the operator with the steps necessary to put the plant into a safer state. The full paper describes how, by the SOFI process, the typical boiling water reactor (BWR) plant, pre-TMI emergency procedures inventory (in some cases, abnormal procedures are included) is broken down to provide the steps to be integrated with the BWR Owners Group Emergency Procedures Guidelines into the SOFI emergency operating procedures. In summary, the paper provides a point-by-point comparison of the SOFI emergency operating procedures solution to the procedural problems identified in the post-TMI reviews

  20. Aiming for a fully integrated computerized procedure system

    International Nuclear Information System (INIS)

    Marron, J. E.

    2006-01-01

    A fully integrated Computerized Procedure System must provide, at a minimum, a) Specification: access to design basis procedures, b) Monitoring: incorporation of real-time plant status, c) Advise: highlighting likely decision paths, and d) Reporting: logging conditions and actions taken. The CPS plays a critical role in overcoming the human factors that lead to accidents. At the same time it can be an essential tool in providing the information and automation to augment what humans do best, identify patterns and make associative leaps in the presence of ambiguous data. Timeliner and TaskGuide are examples of CPS that have evolved from projects in the aerospace industry. They illustrate certain common characteristics of a CPS, namely the knowledge base, user interface, and traceability features. The complexity and number of procedures for a current nuclear project has led to the development of two tools, the Power Generation Control System (PGCS) and the Online Procedure System (OLPS). Together, these systems address the knowledge-base and user interface aspects of a CPS and go a long way in addressing other areas. PGCS and OLPS contain full configuration management capabilities for procedures and the operating recipe. They include administrative functions for online and offline management of documents and data. Some lessons learned from this pair of programs developed by Invensys is the need for more integrated recording mechanisms. The future of CPS is likely to see higher integration of the document access, system status, decision support and logging capabilities. The CPS may evolve into the standard operational interface. Internet technologies that are common-place today have made the possibility of the Active Document a reality. The OPC Foundation is pursuing standards that may accelerate such developments. (authors)

  1. Highly Efficient, Zero-Skew, Integrated Clock Distribution Networks Using Salphasic Principles

    Directory of Open Access Journals (Sweden)

    PASCA, A.

    2016-02-01

    Full Text Available The design of highly efficient clock distributions for integrated circuits is an active topic of research as there will never be a single solution for all systems. For high performance digital or mixed-signal circuits, achieving zero-skew clock over large areas usually comes with high costs in power requirements and design complexity. The present paper shows an overview of a recently proposed technique for ICs - on-die salphasic clock distribution, introduced by the author for CMOS processes. Initially reported in literature for rack-systems, the present paper shows that further refinements are needed for the concept to be applicable on a silicon die. Based on the formation of a standing wave (intrinsically presenting extended in-phase regions with a voltage peak at the input (creating a no-load condition, it is shown that any IC implementation must use transmission lines loss compensation techniques to maintain the proper standing wave configuration. Furthermore, the paper shows theoretical solutions and describes practical on-die techniques for pseudo-spherical bidimensional surfaces, which, with the already reported orthogonal and pseudo-orthogonal structures, can be used to distribute with minimal power requirements a zero-skew clock signal, over large silicon areas.

  2. Mathematical model of the Drosophila circadian clock: loop regulation and transcriptional integration.

    Science.gov (United States)

    Fathallah-Shaykh, Hassan M; Bona, Jerry L; Kadener, Sebastian

    2009-11-04

    Eukaryotic circadian clocks include interconnected positive and negative feedback loops. The clock-cycle dimer (CLK-CYC) and its homolog, CLK-BMAL1, are key transcriptional activators of central components of the Drosophila and mammalian circadian networks, respectively. In Drosophila, negative loops include period-timeless and vrille; positive loops include par domain protein 1. Clockwork orange (CWO) is a recently discovered negative transcription factor with unusual effects on period, timeless, vrille, and par domain protein 1. To understand the actions of this protein, we introduced a new system of ordinary differential equations to model regulatory networks. The model is faithful in the sense that it replicates biological observations. CWO loop actions elevate CLK-CYC; the transcription of direct targets responds by integrating opposing signals from CWO and CLK-CYC. Loop regulation and integration of opposite transcriptional signals appear to be central mechanisms as they also explain paradoxical effects of period gain-of-function and null mutations.

  3. The fully integrated engineer combining technical ability and leadership prowess

    CERN Document Server

    Cerri, Steven T

    2016-01-01

    College teaches you to be a good engineer. But it's likely that your college engineering courses didn't have time to teach you how to effectively contribute your ideas or how to transition to management or leadership. This book provides you with those missing tools. This book addresses the differences between being proficient as a technical individual and effectively contributing to and leading a team to effectively contribute to various projects. The Fully Integrated Engineer: Combining Technical Ability and Leadership Prowess shines a light on how the habits learned in school, while contributing to individual short-term success, actually become hindrances in the modern engineering workplace if your goal is to achieve long-term success as either an engineer, a team lead, manager, or leader. The author offers specific ways to address those limiting habits, turning you into an effective team contributor and leader building toward long-term career succes . The author’s approach to retooling less-than-op...

  4. Integrals for fully correlated Gaussians in relative coordinates

    Science.gov (United States)

    Harris, Frank E.; Monkhorst, Hendrik J.

    This article considers the integrals needed in energy computations on Coulombic systems using many-particle basis functions that are products of Gaussians in all the relative coordinates rij. The formulas presented are applicable to systems with arbitrary numbers of particles and with wave functions containing arbitrary nonnegative powers of all the r 2ij. Recursive procedures for evaluating the integrals are also given, and graph-theoretic representations are provided for multinomials entering the formulation.

  5. Fully Integrated SAW-Less Discrete-Time Superheterodyne Receiver

    NARCIS (Netherlands)

    Madadi, I.

    2015-01-01

    There are nowadays strong business and technical demands to integrate radio- frequency (RF) receivers (RX) into a complete system-on-chip (SoC) realized in scaled digital processes technology. As a consequence, the RF circuitry has to function well in face of reduced power supply ( V DD ) while the

  6. Fully integrated safeguards and security for reprocessing plant monitoring

    International Nuclear Information System (INIS)

    Duran, Felicia Angelica; Ward, Rebecca; Cipiti, Benjamin B.; Middleton, Bobby D.

    2011-01-01

    Nuclear fuel reprocessing plants contain a wealth of plant monitoring data including material measurements, process monitoring, administrative procedures, and physical protection elements. Future facilities are moving in the direction of highly-integrated plant monitoring systems that make efficient use of the plant data to improve monitoring and reduce costs. The Separations and Safeguards Performance Model (SSPM) is an analysis tool that is used for modeling advanced monitoring systems and to determine system response under diversion scenarios. This report both describes the architecture for such a future monitoring system and present results under various diversion scenarios. Improvements made in the past year include the development of statistical tests for detecting material loss, the integration of material balance alarms to improve physical protection, and the integration of administrative procedures. The SSPM has been used to demonstrate how advanced instrumentation (as developed in the Material Protection, Accounting, and Control Technologies campaign) can benefit the overall safeguards system as well as how all instrumentation is tied into the physical protection system. This concept has the potential to greatly improve the probability of detection for both abrupt and protracted diversion of nuclear material.

  7. Network of fully integrated multispecialty hospital imaging systems

    Science.gov (United States)

    Dayhoff, Ruth E.; Kuzmak, Peter M.

    1994-05-01

    The Department of Veterans Affairs (VA) DHCP Imaging System records clinically significant diagnostic images selected by medical specialists in a variety of departments, including radiology, cardiology, gastroenterology, pathology, dermatology, hematology, surgery, podiatry, dental clinic, and emergency room. These images are displayed on workstations located throughout a medical center. All images are managed by the VA's hospital information system, allowing integrated displays of text and image data across medical specialties. Clinicians can view screens of `thumbnail' images for all studies or procedures performed on a selected patient. Two VA medical centers currently have DHCP Imaging Systems installed, and others are planned. All VA medical centers and other VA facilities are connected by a wide area packet-switched network. The VA's electronic mail software has been modified to allow inclusion of binary data such as images in addition to the traditional text data. Testing of this multimedia electronic mail system is underway for medical teleconsultation.

  8. Fully Integrated Biopotential Acquisition Analog Front-End IC.

    Science.gov (United States)

    Song, Haryong; Park, Yunjong; Kim, Hyungseup; Ko, Hyoungho

    2015-09-30

    A biopotential acquisition analog front-end (AFE) integrated circuit (IC) is presented. The biopotential AFE includes a capacitively coupled chopper instrumentation amplifier (CCIA) to achieve low input referred noise (IRN) and to block unwanted DC potential signals. A DC servo loop (DSL) is designed to minimize the offset voltage in the chopper amplifier and low frequency respiration artifacts. An AC coupled ripple rejection loop (RRL) is employed to reduce ripple due to chopper stabilization. A capacitive impedance boosting loop (CIBL) is designed to enhance the input impedance and common mode rejection ratio (CMRR) without additional power consumption, even under an external electrode mismatch. The AFE IC consists of two-stage CCIA that include three compensation loops (DSL, RRL, and CIBL) at each CCIA stage. The biopotential AFE is fabricated using a 0.18 μm one polysilicon and six metal layers (1P6M) complementary metal oxide semiconductor (CMOS) process. The core chip size of the AFE without input/output (I/O) pads is 10.5 mm². A fourth-order band-pass filter (BPF) with a pass-band in the band-width from 1 Hz to 100 Hz was integrated to attenuate unwanted signal and noise. The overall gain and band-width are reconfigurable by using programmable capacitors. The IRN is measured to be 0.94 μVRMS in the pass band. The maximum amplifying gain of the pass-band was measured as 71.9 dB. The CIBL enhances the CMRR from 57.9 dB to 67 dB at 60 Hz under electrode mismatch conditions.

  9. Fully Integrated Biopotential Acquisition Analog Front-End IC

    Directory of Open Access Journals (Sweden)

    Haryong Song

    2015-09-01

    Full Text Available A biopotential acquisition analog front-end (AFE integrated circuit (IC is presented. The biopotential AFE includes a capacitively coupled chopper instrumentation amplifier (CCIA to achieve low input referred noise (IRN and to block unwanted DC potential signals. A DC servo loop (DSL is designed to minimize the offset voltage in the chopper amplifier and low frequency respiration artifacts. An AC coupled ripple rejection loop (RRL is employed to reduce ripple due to chopper stabilization. A capacitive impedance boosting loop (CIBL is designed to enhance the input impedance and common mode rejection ratio (CMRR without additional power consumption, even under an external electrode mismatch. The AFE IC consists of two-stage CCIA that include three compensation loops (DSL, RRL, and CIBL at each CCIA stage. The biopotential AFE is fabricated using a 0.18 μm one polysilicon and six metal layers (1P6M complementary metal oxide semiconductor (CMOS process. The core chip size of the AFE without input/output (I/O pads is 10.5 mm2. A fourth-order band-pass filter (BPF with a pass-band in the band-width from 1 Hz to 100 Hz was integrated to attenuate unwanted signal and noise. The overall gain and band-width are reconfigurable by using programmable capacitors. The IRN is measured to be 0.94 μVRMS in the pass band. The maximum amplifying gain of the pass-band was measured as 71.9 dB. The CIBL enhances the CMRR from 57.9 dB to 67 dB at 60 Hz under electrode mismatch conditions.

  10. User-Defined Clocks in the Real-Time Specification for Java

    DEFF Research Database (Denmark)

    Wellings, Andy; Schoeberl, Martin

    2011-01-01

    This paper analyses the new user-defined clock model that is to be supported in Version 1.1 of the Real-Time Specification for Java (RTSJ). The model is a compromise between the current position, where there is no support for user-defined clocks, and a fully integrated model. The paper investigates...... the implications of supporting a fully generalized model from both the specification’s and an implementation’s viewpoint. It concludes that for RTSJ the scope of changes required to fully integrate user-defined clocks into the specification would have a major impact on current implementations....

  11. VISA Final Report: Fully Integrated Power Electronic Systems in Automotive Electronics

    NARCIS (Netherlands)

    Waffenschmidt, E.

    2011-01-01

    This report summarizes the activities related to the public funded project “Vollintegrierte leistungselektronische Systeme in der Automobilelektronik – VISA” (Fully Integrated Power Electronic Systems in Automotive Electronics). Aim of the project is to investigate the integration of components into

  12. Photonic integrated circuit implementation of a sub-GHz-selectivity frequency comb filter for optical clock multiplication.

    Science.gov (United States)

    Geng, Zihan; Xie, Yiwei; Zhuang, Leimeng; Burla, Maurizio; Hoekman, Marcel; Roeloffzen, Chris G H; Lowery, Arthur J

    2017-10-30

    We report a photonic integrated circuit implementation of an optical clock multiplier, or equivalently an optical frequency comb filter. The circuit comprises a novel topology of a ring-resonator-assisted asymmetrical Mach-Zehnder interferometer in a Sagnac loop, providing a reconfigurable comb filter with sub-GHz selectivity and low complexity. A proof-of-concept device is fabricated in a high-index-contrast stoichiometric silicon nitride (Si 3 N 4 /SiO 2 ) waveguide, featuring low loss, small size, and large bandwidth. In the experiment, we show a very narrow passband for filters of this kind, i.e. a -3-dB bandwidth of 0.6 GHz and a -20-dB passband of 1.2 GHz at a frequency interval of 12.5 GHz. As an application example, this particular filter shape enables successful demonstrations of five-fold repetition rate multiplication of optical clock signals, i.e. from 2.5 Gpulses/s to 12.5 Gpulses/s and from 10 Gpulses/s to 50 Gpulses/s. This work addresses comb spectrum processing on an integrated platform, pointing towards a device-compact solution for optical clock multipliers (frequency comb filters) which have diverse applications ranging from photonic-based RF spectrum scanners and photonic radars to GHz-granularity WDM switches and LIDARs.

  13. Towards a fully-fledged integration of spiritual care and medical care

    NARCIS (Netherlands)

    Kruizinga, R.; Scherer-Rath, M.; Schilderman, J.B.A.M.; Puchalski, C.; Laarhoven, H.W.M. van

    2018-01-01

    In this article, we aimed to set out current problems that hinder a fully fledged integration of spiritual and medical care, which address these obstacles. We discuss the following five statements: 1) spiritual care requires a clear and inclusive definition of spirituality; 2) empirical evidence for

  14. Fully integrated microfluidic measurement system for real-time determination of gas and liquid mixtures composition

    NARCIS (Netherlands)

    Lötters, Joost Conrad; Groenesteijn, Jarno; van der Wouden, E.J.; Sparreboom, Wouter; Lammerink, Theodorus S.J.; Wiegerink, Remco J.

    2015-01-01

    We have designed and realised a fully integrated microfluidic measurement system for real-time determination of both flow rate and composition of gas- and liquid mixtures. The system comprises relative permittivity sensors, pressure sensors, a Coriolis flow and density sensor, a thermal flow sensor

  15. Fully integrated carbon nanotube composite thin film strain sensors on flexible substrates for structural health monitoring

    Science.gov (United States)

    Burton, A. R.; Lynch, J. P.; Kurata, M.; Law, K. H.

    2017-09-01

    Multifunctional thin film materials have opened many opportunities for novel sensing strategies for structural health monitoring. While past work has established methods of optimizing multifunctional materials to exhibit sensing properties, comparatively less work has focused on their integration into fully functional sensing systems capable of being deployed in the field. This study focuses on the advancement of a scalable fabrication process for the integration of multifunctional thin films into a fully integrated sensing system. This is achieved through the development of an optimized fabrication process that can create a broad range of sensing systems using multifunctional materials. A layer-by-layer deposited multifunctional composite consisting of single walled carbon nanotubes (SWNT) in a polyvinyl alcohol and polysodium-4-styrene sulfonate matrix are incorporated with a lithography process to produce a fully integrated sensing system deposited on a flexible substrate. To illustrate the process, a strain sensing platform consisting of a patterned SWNT-composite thin film as a strain-sensitive element within an amplified Wheatstone bridge sensing circuit is presented. Strain sensing is selected because it presents many of the design and processing challenges that are core to patterning multifunctional thin film materials into sensing systems. Strain sensors fabricated on a flexible polyimide substrate are experimentally tested under cyclic loading using standard four-point bending coupons and a partial-scale steel frame assembly under lateral loading. The study reveals the material process is highly repeatable to produce fully integrated strain sensors with linearity and sensitivity exceeding 0.99 and 5 {{V}}/{ε }, respectively. The thin film strain sensors are robust and are capable of high strain measurements beyond 3000 μ {ε }.

  16. A Fully Integrated Nanosystem of Semiconductor Nanowires for Direct Solar Water Splitting

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chong; Tang, Jinyao; Chen, Hao Ming; Liu, Bin; Yang, Peidong

    2013-06-12

    Artificial photosynthesis, the biomimetic approach to converting sunlight?s energy directly into chemical fuels, aims to imitate nature by using an integrated system of nanostructures, each of which plays a specific role in the sunlight-to-fuel conversion process. Here we describe a fully integrated system of nanoscale photoelectrodes assembled from inorganic nanowires for direct solar water splitting. Similar to the photosynthetic system in a chloroplast, the artificial photosynthetic system comprises two semiconductor light absorbers with large surface area, an interfacial layer for charge transport, and spatially separated cocatalysts to facilitate the water reduction and oxidation. Under simulated sunlight, a 0.12percent solar-to-fuel conversion efficiency is achieved, which is comparable to that of natural photosynthesis. The result demonstrates the possibility of integrating material components into a functional system that mimics the nanoscopic integration in chloroplasts. It also provides a conceptual blueprint of modular design that allows incorporation of newly discovered components for improved performance.

  17. Efficient uncertainty quantification in fully-integrated surface and subsurface hydrologic simulations

    Science.gov (United States)

    Miller, K. L.; Berg, S. J.; Davison, J. H.; Sudicky, E. A.; Forsyth, P. A.

    2018-01-01

    Although high performance computers and advanced numerical methods have made the application of fully-integrated surface and subsurface flow and transport models such as HydroGeoSphere common place, run times for large complex basin models can still be on the order of days to weeks, thus, limiting the usefulness of traditional workhorse algorithms for uncertainty quantification (UQ) such as Latin Hypercube simulation (LHS) or Monte Carlo simulation (MCS), which generally require thousands of simulations to achieve an acceptable level of accuracy. In this paper we investigate non-intrusive polynomial chaos for uncertainty quantification, which in contrast to random sampling methods (e.g., LHS and MCS), represents a model response of interest as a weighted sum of polynomials over the random inputs. Once a chaos expansion has been constructed, approximating the mean, covariance, probability density function, cumulative distribution function, and other common statistics as well as local and global sensitivity measures is straightforward and computationally inexpensive, thus making PCE an attractive UQ method for hydrologic models with long run times. Our polynomial chaos implementation was validated through comparison with analytical solutions as well as solutions obtained via LHS for simple numerical problems. It was then used to quantify parametric uncertainty in a series of numerical problems with increasing complexity, including a two-dimensional fully-saturated, steady flow and transient transport problem with six uncertain parameters and one quantity of interest; a one-dimensional variably-saturated column test involving transient flow and transport, four uncertain parameters, and two quantities of interest at 101 spatial locations and five different times each (1010 total); and a three-dimensional fully-integrated surface and subsurface flow and transport problem for a small test catchment involving seven uncertain parameters and three quantities of interest at

  18. A highly linear fully integrated powerline filter for biopotential acquisition systems.

    Science.gov (United States)

    Alzaher, Hussain A; Tasadduq, Noman; Mahnashi, Yaqub

    2013-10-01

    Powerline interference is one of the most dominant problems in detection and processing of biopotential signals. This work presents a new fully integrated notch filter exhibiting high linearity and low power consumption. High filter linearity is preserved utilizing active-RC approach while IC implementation is achieved through replacing passive resistors by R-2R ladders achieving area saving of approximately 120 times. The filter design is optimized for low power operation using an efficient circuit topology and an ultra-low power operational amplifier. Fully differential implementation of the proposed filter shows notch depth of 43 dB (78 dB for 4th-order) with THD of better than -70 dB while consuming about 150 nW from 1.5 V supply.

  19. A fully integrated UHF RFID reader SoC for handheld applications in the 0.18 μm CMOS process

    International Nuclear Information System (INIS)

    Wang Jingchao; Zhang Chun; Wang Zhihua

    2010-01-01

    A low cost fully integrated single-chip UHF radio frequency identification (RFID) reader SoC for short distance handheld applications is presented. The SoC integrates all building blocks-including an RF transceiver, a PLL frequency synthesizer, a digital baseband and an MCU-in a 0.18 μm CMOS process. A high-linearity RX front-end is designed to handle the large self-interferer. A class-E power amplifier with high power efficiency is also integrated to fulfill the function of a UHF passive RFID reader. The measured maximum output power of the transmitter is 20.28 dBm and the measured receiver sensitivity is -60 dBm. The digital baseband including MCU core consumes 3.91 mW with a clock of 10 MHz and the analog part including power amplifier consumes 368.4 mW. The chip has a die area of 5.1 x 3.8 mm 2 including pads. (semiconductor integrated circuits)

  20. Developing a fully integrated tobacco curriculum in medical colleges in India.

    Science.gov (United States)

    Yamini, T R; Nichter, Mark; Nichter, Mimi; Sairu, P; Aswathy, S; Leelamoni, K; Unnikrishnan, B; P, Prasanna Mithra; Thapar, Rekha; Basha, S R; Jayasree, A K; Mayamol, T R; Muramoto, Myra; Mini, G K; Thankappan, K R

    2015-05-20

    This paper describes a pioneering effort to introduce tobacco cessation into India's undergraduate medical college curriculum. This is the first ever attempt to fully integrate tobacco control across all years of medical college in any low and middle income country. The development, pretesting, and piloting of an innovative modular tobacco curriculum are discussed as well as challenges that face implementation and steps taken to address them and to advocate for adoption by the Medical Council of India. In-depth interviews were conducted with administrators and faculty in five medical colleges to determine interest in and willingness to fully integrate smoking cessation into the college curriculum. Current curriculum was reviewed for present exposure to information about tobacco and cessation skill training. A modular tobacco curriculum was developed, pretested, modified, piloted, and evaluated by faculty and students. Qualitative research was conducted to identify challenges to future curriculum implementation. Fifteen modules were successfully developed focusing on the public health importance of tobacco control, the relationship between tobacco and specific organ systems, diseases related to smoking and chewing tobacco, and the impact of tobacco on medication effectiveness. Culturally sensitive illness specific cessation training videos were developed. Faculty and students positively evaluated the curriculum as increasing their competency to support cessation during illness as a teachable moment. Students conducted illness centered cessation interviews with patients as a mandated part of their coursework. Systemic challenges to implementing the curriculum were identified and addressed. A fully integrated tobacco curriculum for medical colleges was piloted in 5 colleges and is now freely available online. The curriculum has been adopted by the state of Kerala as a first step to gaining Medical Council of India review and possible recognition.

  1. A fully integrated preamplifier for cardiac sensing in a HV-CMOS technology.

    Science.gov (United States)

    Lasa, J; Arnaud, A; Miguez, M

    2010-01-01

    A novel fully integrated preamplifier stage for cardiac activity sensing is presented. The proposed design takes advantage of the High Voltage CMOS (HV) technology properties to comply with the safety requirements of implantable devices without the addition of external decoupling capacitors. The power consumption is minimum; while the input referred noise is kept well below the minimum signal to be sensed. This first stage is a high pass filter with a cut off frequency at 75Hz, and 25db gain. Simulation results are presented, the circuit is being fabricated in a 0.6 microm technology.

  2. The fully integrated biomedical engineering programme at Eindhoven University of Technology.

    Science.gov (United States)

    Slaaf, D W; van Genderen, M H P

    2009-05-01

    The development of a fully integrated biomedical engineering programme (life sciences included from the start) is described. Details are provided about background, implementation, and didactic concept: design centred learning combined with courses. The curriculum has developed into a bachelor-master's programme with two different master's degrees: Master's Degree in Biomedical Engineering and Master's Degree in Medical Engineering. Recently, the programme has adopted semester programming, has included a major and minor in the bachelor's degree phase, and a true bachelor's degree final project. Details about the programme and data about where graduates find jobs are provided in this paper.

  3. Implementation of integrated circuit and design of SAR ADC for fully implantable hearing aids.

    Science.gov (United States)

    Kim, Jong Hoon; Lee, Jyung Hyun; Cho, Jin-Ho

    2017-07-20

    The hearing impaired population has been increasing; many people suffer from hearing problems. To deal with this difficulty, various types of hearing aids are being rapidly developed. In particular, fully implantable hearing aids are being actively studied to improve the performance of existing hearing aids and to reduce the stigma of hearing loss patients. It has to be of small size and low-power consumption for easy implantation and long-term use. The objective of the study was to implement a small size and low-power consumption successive approximation register analog-to-digital converter (SAR ADC) for fully implantable hearing aids. The ADC was selected as the SAR ADC because its analog circuit components are less required by the feedback circuit of the SAR ADC than the sigma-delta ADC which is conventionally used in hearing aids, and it has advantages in the area and power consumption. So, the circuit of SAR ADC is designed considering the speech region of humans because the objective is to deliver the speech signals of humans to hearing loss patients. If the switch of sample and hold works in the on/off positions, the charge injection and clock feedthrough are produced by a parasitic capacitor. These problems affect the linearity of the hold voltage, and as a result, an error of the bit conversion is generated. In order to solve the problem, a CMOS switch that consists of NMOS and PMOS was used, and it reduces the charge injection because the charge carriers in the NMOS and PMOS have inversed polarity. So, 16 bit conversion is performed before the occurrence of the Least Significant Bit (LSB) error. In order to minimize the offset voltage and power consumption of the designed comparator, we designed a preamplifier with current mirror. Therefore, the power consumption was reduced by the power control switch used in the comparator. The layout of the designed SAR ADC was performed by Virtuoso Layout Editor (Cadence, USA). In the layout result, the size of the

  4. Fully transparent quantum dot light-emitting diode integrated with graphene anode and cathode.

    Science.gov (United States)

    Seo, Jung-Tak; Han, Junebeom; Lim, Taekyung; Lee, Ki-Heon; Hwang, Jungseek; Yang, Heesun; Ju, Sanghyun

    2014-12-23

    A fully transparent quantum dot light-emitting diode (QD-LED) was fabricated by incorporating two types (anode and cathode) of graphene-based electrodes, which were controlled in their work functions and sheet resistances. Either gold nanoparticles or silver nanowires were inserted between layers of graphene to control the work function, whereas the sheet resistance was determined by the number of graphene layers. The inserted gold nanoparticles or silver nanowires in graphene films caused a charge transfer and changed the work function to 4.9 and 4.3 eV, respectively, from the original work function (4.5 eV) of pristine graphene. Moreover the sheet resistance values for the anode and cathode electrodes were improved from ∼63,000 to ∼110 Ω/sq and from ∼100,000 to ∼741 Ω/sq as the number of graphene layers increased from 1 to 12 and from 1 to 8, respectively. The main peak wavelength, luminance, current efficiency, and optical transmittance of the fully transparent QD-LED integrated with graphene anode and cathode were 535 nm, ∼358 cd/m2, ∼0.45 cd/A, and 70-80%, respectively. The findings of the study are expected to lay a foundation for the production of high-efficiency, fully transparent, and flexible displays using graphene-based electrodes.

  5. Note: Fully integrated 3.2 Gbps quantum random number generator with real-time extraction

    International Nuclear Information System (INIS)

    Zhang, Xiao-Guang; Nie, You-Qi; Liang, Hao; Zhang, Jun; Pan, Jian-Wei; Zhou, Hongyi; Ma, Xiongfeng

    2016-01-01

    We present a real-time and fully integrated quantum random number generator (QRNG) by measuring laser phase fluctuations. The QRNG scheme based on laser phase fluctuations is featured for its capability of generating ultra-high-speed random numbers. However, the speed bottleneck of a practical QRNG lies on the limited speed of randomness extraction. To close the gap between the fast randomness generation and the slow post-processing, we propose a pipeline extraction algorithm based on Toeplitz matrix hashing and implement it in a high-speed field-programmable gate array. Further, all the QRNG components are integrated into a module, including a compact and actively stabilized interferometer, high-speed data acquisition, and real-time data post-processing and transmission. The final generation rate of the QRNG module with real-time extraction can reach 3.2 Gbps.

  6. Demographic characteristics of patients using a fully integrated psychosocial support service for cancer patients

    Directory of Open Access Journals (Sweden)

    Hope Teresa

    2009-12-01

    Full Text Available Abstract Background Psychosocial support services are an important component of modern cancer treatment. A major challenge for all psychosocial services is the achievement of equity of use. Previous studies in the UK have found that women of higher socio-economic status with breast cancer were over-represented amongst those accessing support services. People with other cancer diagnoses, those from socio-economically deprived areas, and men, were under-represented. Findings The Oncology Health Service, Kingston Upon Hull, UK, delivers fully integrated psychosocial support and interventions. To assess equity of access in this service, a cross-sectional study of all patients with cancer accessing the service during a 5 day period was carried out. One hundred and forty-five patients attended. Forty four percent were male, and the types of cancer were broadly in the proportions expected on the basis of population prevalence (breast cancer 22%, colorectal cancer 21%, lung cancer 16%. Sixty six percent came from the three most deprived quintiles of the Townsend deprivation Index. Conclusions The fully integrated Oncology Health Service in Hull is accessed by a more diverse range of patients than previously reported for other services, and is an example of a model of service by which socially equitable use of psychosocial support in the National Health Service might be achieved.

  7. Implementing the theories: A fully integrated project control system that's implemented and works

    International Nuclear Information System (INIS)

    Harris, R.E.

    1994-01-01

    Using the theories presented in DOE Orders 4700.1, 1332.1A, and Notice 4700.5 as the basis for system design, the Fernald Environmental Restoration Management Corporation (FERMCO) has developed and implemented a Project Control System (PCS) that complies with requirements and provides DOE and FERMCO management with timely performance measurement information. To this extent, the FERMCO PCS probably is similar to the systems of the majority of the contractors in the DOE complex. In fact. this facet of the FERMCO PCS generally mirrors those used on projects around the world by FERMCO's parent company, Fluor Daniel. Starting with this open-quotes platformclose quotes, the vision and challenge of creating a fully integrated system commenced. An open-architecture systems approach is the factor that most greatly influenced and enabled the successful development and implementation of the Project Control System for the Fernald Environmental Management Project. All aspects of a fully integrated system were considered during the design phase. The architecture of the FERMCO system enables seamless, near real-time, transfer of data both from and to the Project Control System with all other related systems. The primary systems that provide and share data with the Project Control System include those used by the Payroll, Accounting, Procurement, and Human Resources organizations. To enable data linking with these organizations, the resource codes were designed to map many-to-one from their detailed codes to the summarized codes used in the PCS

  8. Fully integrated modelling for sustainability assessment of resource recovery from waste.

    Science.gov (United States)

    Millward-Hopkins, Joel; Busch, Jonathan; Purnell, Phil; Zwirner, Oliver; Velis, Costas A; Brown, Andrew; Hahladakis, John; Iacovidou, Eleni

    2018-01-15

    This paper presents an integrated modelling approach for value assessments, focusing on resource recovery from waste. The method tracks and forecasts a range of values across environmental, social, economic and technical domains by attaching these to material-flows, thus building upon and integrating unidimensional models such as material flow analysis (MFA) and lifecycle assessment (LCA). We argue that the usual classification of metrics into these separate domains is useful for interpreting the outputs of multidimensional assessments, but unnecessary for modelling. We thus suggest that multidimensional assessments can be better performed by integrating the calculation methods of unidimensional models rather than their outputs. To achieve this, we propose a new metric typology that forms the foundation of a multidimensional model. This enables dynamic simulations to be performed with material-flows (or values in any domain) driven by changes in value in other domains. We then apply the model in an illustrative case highlighting links between the UK coal-based electricity-production and concrete/cement industries, investigating potential impacts that may follow the increased use of low-carbon fuels (biomass and solid recovered fuels; SRF) in the former. We explore synergies and trade-offs in value across domains and regions, e.g. how changes in carbon emissions in one part of the system may affect mortality elsewhere. This highlights the advantages of recognising complex system dynamics and making high-level inferences of their effects, even when rigorous analysis is not possible. We also indicate how changes in social, environmental and economic 'values' can be understood as being driven by changes in the technical value of resources. Our work thus emphasises the advantages of building fully integrated models to inform conventional sustainability assessments, rather than applying hybrid approaches that integrate outputs from parallel models. The approach we

  9. The 128-channel fully differential digital integrated neural recording and stimulation interface.

    Science.gov (United States)

    Shahrokhi, Farzaneh; Abdelhalim, Karim; Serletis, Demitre; Carlen, Peter L; Genov, Roman

    2010-06-01

    We present a fully differential 128-channel integrated neural interface. It consists of an array of 8 X 16 low-power low-noise signal-recording and generation circuits for electrical neural activity monitoring and stimulation, respectively. The recording channel has two stages of signal amplification and conditioning with and a fully differential 8-b column-parallel successive approximation (SAR) analog-to-digital converter (ADC). The total measured power consumption of each recording channel, including the SAR ADC, is 15.5 ¿W. The measured input-referred noise is 6.08 ¿ Vrms over a 5-kHz bandwidth, resulting in a noise efficiency factor of 5.6. The stimulation channel performs monophasic or biphasic voltage-mode stimulation, with a maximum stimulation current of 5 mA and a quiescent power dissipation of 51.5 ¿W. The design is implemented in 0.35-¿m complementary metal-oxide semiconductor technology with the channel pitch of 200 ¿m for a total die size of 3.4 mm × 2.5 mm and a total power consumption of 9.33 mW. The neural interface was validated in in vitro recording of a low-Mg(2+)/high-K(+) epileptic seizure model in an intact hippocampus of a mouse.

  10. Fully implicit solution of large-scale non-equilibrium radiation diffusion with high order time integration

    International Nuclear Information System (INIS)

    Brown, Peter N.; Shumaker, Dana E.; Woodward, Carol S.

    2005-01-01

    We present a solution method for fully implicit radiation diffusion problems discretized on meshes having millions of spatial zones. This solution method makes use of high order in time integration techniques, inexact Newton-Krylov nonlinear solvers, and multigrid preconditioners. We explore the advantages and disadvantages of high order time integration methods for the fully implicit formulation on both two- and three-dimensional problems with tabulated opacities and highly nonlinear fusion source terms

  11. H∞ output-feedback fuzzy proportional-integral control of fully delayed input/output systems.

    Science.gov (United States)

    Chiu, Chian-Song; Chiang, Tung-Sheng

    2017-01-01

    This paper presents the output-feedback fuzzy proportional-integral (PI) controller design for uncertain nonlinear systems with both fully delayed input and output. Based on the Takagi-Sugeno (T-S) fuzzy model representation, the output-feedback PI control is realized via parallel distributed PI compensation and novel LMI gain design. Although the T-S fuzzy PI controller is simple, asymptotic output regulation is assured to overcome the effect of uncertainty, state delay, and full input/output delays. When considering disturbance and measurement noise, the control performance is achieved by robust gain design. Furthermore, state observers and bilinear matrix inequality conditions are removed in this paper. Finally, time-delay Chua׳s circuit system and a continuous-time stirred tank reactor are taken as applications to show the expected performance. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  12. A Fully Integrated Humidity Sensor System-on-Chip Fabricated by Micro-Stamping Technology

    Directory of Open Access Journals (Sweden)

    Chih-Ting Lin

    2012-08-01

    Full Text Available A fully integrated humidity sensor chip was designed, implemented, and tested. Utilizing the micro-stamping technology, the pseudo-3D sensor system-on-chip (SSoC architecture can be implemented by stacking sensing materials directly on the top of a CMOS-fabricated chip. The fabricated sensor system-on-chip (2.28 mm × 2.48 mm integrated a humidity sensor, an interface circuit, a digital controller, and an On-Off Keying (OOK wireless transceiver. With low power consumption, i.e., 750 μW without RF operation, the sensitivity of developed sensor chip was experimentally verified in the relative humidity (RH range from 32% to 60%. The response time of the chip was also experimentally verified to be within 5 seconds from RH 36% to RH 64%. As a consequence, the implemented humidity SSoC paves the way toward the an ultra-small sensor system for various applications.

  13. 3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer.

    Science.gov (United States)

    Asano, Sho; Muroyama, Masanori; Nakayama, Takahiro; Hata, Yoshiyuki; Nonomura, Yutaka; Tanaka, Shuji

    2017-10-25

    This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D)-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively.

  14. 3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer

    Directory of Open Access Journals (Sweden)

    Sho Asano

    2017-10-01

    Full Text Available This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS with capacitive sensing circuits on a low temperature cofired ceramic (LTCC interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively.

  15. Design and implementation of a high sensitivity fully integrated passive UHF RFID tag

    International Nuclear Information System (INIS)

    Li Shoucheng; Wang Xin'an; Lin Ke; Shen Jinpeng; Zhang Jinhai

    2014-01-01

    A fully integrated passive UHF RFID tag complying with the ISO18000-6B protocol is presented, which includes an analog front-end, a baseband processor, and an EEPROM memory. To extend the communication range, a high efficiency differential-drive CMOS rectifier is adopted. A novel high performance voltage limiter is used to provide a stable limiting voltage, with a 172 mV voltage variation against temperature variation and process dispersion. The dynamic band-enhancement technique is used in the regulator circuit to improve the regulating capacity. A rail-to-rail hysteresis comparator is adopted to demodulate the signal correctly in any condition. The whole transponder chip is implemented in a 0.18 μm CMOS process, with a die size of 900 × 800 μm 2 . Our measurement results show that the total power consumption of the tag chip is only 6.8 μW, with a sensitivity of −13.5 dBm (semiconductor integrated circuits)

  16. Towards a fully integrated optical gyroscope using whispering gallery modes resonators

    Science.gov (United States)

    Amrane, T.; Jager, J.-B.; Jager, T.; Calvo, V.; Léger, J.-M.

    2017-11-01

    Since the developments of lasers and the optical fibers in the 70s, the optical gyroscopes have been subject to an intensive research to improve both their resolution and stability performances. However the best optical gyroscopes currently on the market, the ring laser gyroscope and the interferometer fiber optic gyroscope are still macroscopic devices and cannot address specific applications where size and weight constraints are critical. One solution to overcome these limitations could be to use an integrated resonator as a sensitive part to build a fully Integrated Optical Resonant Gyroscope (IORG). To keep a high rotation sensitivity, which is usually degraded when downsizing this kind of optical sensors based on the Sagnac effect, the resonator has to exhibit a very high quality factor (Q): as detailed in equation (1) where the minimum rotation rate resolution for an IORG is given as a function of the resonator characteristics (Q and diameter D) and of the global system optical system characteristics (i.e. SNR and bandwidth B), the higher the Q×D product, the lower the resolution.

  17. A fully Bayesian latent variable model for integrative clustering analysis of multi-type omics data.

    Science.gov (United States)

    Mo, Qianxing; Shen, Ronglai; Guo, Cui; Vannucci, Marina; Chan, Keith S; Hilsenbeck, Susan G

    2018-01-01

    Identification of clinically relevant tumor subtypes and omics signatures is an important task in cancer translational research for precision medicine. Large-scale genomic profiling studies such as The Cancer Genome Atlas (TCGA) Research Network have generated vast amounts of genomic, transcriptomic, epigenomic, and proteomic data. While these studies have provided great resources for researchers to discover clinically relevant tumor subtypes and driver molecular alterations, there are few computationally efficient methods and tools for integrative clustering analysis of these multi-type omics data. Therefore, the aim of this article is to develop a fully Bayesian latent variable method (called iClusterBayes) that can jointly model omics data of continuous and discrete data types for identification of tumor subtypes and relevant omics features. Specifically, the proposed method uses a few latent variables to capture the inherent structure of multiple omics data sets to achieve joint dimension reduction. As a result, the tumor samples can be clustered in the latent variable space and relevant omics features that drive the sample clustering are identified through Bayesian variable selection. This method significantly improve on the existing integrative clustering method iClusterPlus in terms of statistical inference and computational speed. By analyzing TCGA and simulated data sets, we demonstrate the excellent performance of the proposed method in revealing clinically meaningful tumor subtypes and driver omics features. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Fully integrated reflection-mode photoacoustic, two-photon, and second harmonic generation microscopy in vivo

    Science.gov (United States)

    Song, Wei; Xu, Qiang; Zhang, Yang; Zhan, Yang; Zheng, Wei; Song, Liang

    2016-08-01

    The ability to obtain comprehensive structural and functional information from intact biological tissue in vivo is highly desirable for many important biomedical applications, including cancer and brain studies. Here, we developed a fully integrated multimodal microscopy that can provide photoacoustic (optical absorption), two-photon (fluorescence), and second harmonic generation (SHG) information from tissue in vivo, with intrinsically co-registered images. Moreover, using a delicately designed optical-acoustic coupling configuration, a high-frequency miniature ultrasonic transducer was integrated into a water-immersion optical objective, thus allowing all three imaging modalities to provide a high lateral resolution of ~290 nm with reflection-mode imaging capability, which is essential for studying intricate anatomy, such as that of the brain. Taking advantage of the complementary and comprehensive contrasts of the system, we demonstrated high-resolution imaging of various tissues in living mice, including microvasculature (by photoacoustics), epidermis cells, cortical neurons (by two-photon fluorescence), and extracellular collagen fibers (by SHG). The intrinsic image co-registration of the three modalities conveniently provided improved visualization and understanding of the tissue microarchitecture. The reported results suggest that, by revealing complementary tissue microstructures in vivo, this multimodal microscopy can potentially facilitate a broad range of biomedical studies, such as imaging of the tumor microenvironment and neurovascular coupling.

  19. Design of multilayered grating couplers as key elements of a fully integrated IR-absorption sensor

    Science.gov (United States)

    Kasberger, Juergen; Jakoby, Bernhard

    2008-08-01

    For the online characterization of fluids regarding their chemical composition, the miniaturization of an IR-absorption sensor at application-specific distinguished wavelengths for the mid-IR-region promises outstanding features. Utilizing micromachining technology facilitates the integration of all required components (including thermal emitter and detector) into a complete sensor system. The absorption is sensed in the evanescent field of an appropriately designed slab mono-mode waveguide (ZnSe, n=2.42) residing on a BaF2-substrate (n=1.44), which represents the central element of the system. A typical application for such a system is, e.g., the characterization of engine oil oxidation in terms of the absorption at 5.85 μm as an indicator for deterioration. The thermal generation and detection of mid-IR-radiation is preferred over expensive and sophisticated quantum well devices. However, the spatial and non-coherent character of thermally generated IR-radiation requires an extension of the numerical methods established for coherent light sources for a proper design of the system's grating couplers, which act as key elements determining the system performance. These couplers yield efficient coupling into and out of the sensing waveguide and provide the required spectral filtering at the same time. In the actually projected implementation, a multilayer waveguide Si/BaF2/ZnSe is used, where the silicon substrate practically represents a rear-reflector in the grating region featuring several advantages compared to simpler grating couplers. In this contribution we discuss the modelling of the coupling of non-coherent, thermally generated and detected IR-radiation by means of these multilayer grating couplers in the context of a fully integrated IR-absorption sensor system.

  20. MODFLOW-OWHM v2: The next generation of fully integrated hydrologic simulation software

    Science.gov (United States)

    Boyce, S. E.; Hanson, R. T.; Ferguson, I. M.; Reimann, T.; Henson, W.; Mehl, S.; Leake, S.; Maddock, T.

    2016-12-01

    The One-Water Hydrologic Flow Model (One-Water) is a MODFLOW-based integrated hydrologic flow model designed for the analysis of a broad range of conjunctive-use and climate-related issues. One-Water fully links the movement and use of groundwater, surface water, and imported water for consumption by agriculture and natural vegetation on the landscape, and for potable and other uses within a supply-and-demand framework. One-Water includes linkages for deformation-, flow-, and head-dependent flows; additional observation and parameter options for higher-order calibrations; and redesigned code for facilitation of self-updating models and faster simulation run times. The next version of One-Water, currently under development, will include a new surface-water operations module that simulates dynamic reservoir operations, a new sustainability analysis package that facilitates the estimation and simulation of reduced storage depletion and captured discharge, a conduit-flow process for karst aquifers and leaky pipe networks, a soil zone process that adds an enhanced infiltration process, interflow, deep percolation and soil moisture, and a new subsidence and aquifer compaction package. It will also include enhancements to local grid refinement, and additional features to facilitate easier model updates, faster execution, better error messages, and more integration/cross communication between the traditional MODFLOW packages. By retaining and tracking the water within the hydrosphere, One-Water accounts for "all of the water everywhere and all of the time." This philosophy provides more confidence in the water accounting by the scientific community and provides the public a foundation needed to address wider classes of problems. Ultimately, more complex questions are being asked about water resources, so they require a more complete answer about conjunctive-use and climate-related issues.

  1. A fully integrated multi-standard frequency synthesizer for GNSS receivers with cellular network positioning capability

    Science.gov (United States)

    Bin, Li; Xiangning, Fan; Wei, Li; Li, Zhang; Zhigong, Wang

    2013-01-01

    A fully integrated hybrid integer/fractional frequency synthesizer is presented. With a single multiband voltage-controlled-oscillator (VCO), the frequency synthesizer can support GPS, Galileo, Compass and TD-SCDMA standards. Design is carefully performed to trade off power, die area and phase noise performance. By reconfiguring between the integer mode and fractional mode, different frequency resolution requirements and a constant loop bandwidth for each standard can be achieved simultaneously. Moreover, a long sequence length, reduced hardware complexity multi-stage-noise-shaping (MASH) Δ-Σ modulator is employed to reduce fractional spur in the fractional mode. Fabricated in a 0.18 μm CMOS technology, the frequency synthesizer occupies an active area of 1.48 mm2 and draws a current of 13.4-16.2 mA from a 1.8 V power supply. The measured phase noise is lower than -80 dBc/Hz at 100 kHz offset and -113 to -124 dBc/Hz at 1 MHz offset respectively, while the measured reference spur is -71 dBc in integer mode and the fractional spur is -65 dBc in fractional mode.

  2. Mechatronic design of a fully integrated camera for mini-invasive surgery.

    Science.gov (United States)

    Zazzarini, C C; Patete, P; Baroni, G; Cerveri, P

    2013-06-01

    This paper describes the design features of an innovative fully integrated camera candidate for mini-invasive abdominal surgery with single port or transluminal access. The apparatus includes a CMOS imaging sensor, a light-emitting diode (LED)-based unit for scene illumination, a photodiode for luminance detection, an optical system designed according to the mechanical compensation paradigm, an actuation unit for enabling autofocus and optical zoom, and a control logics based on microcontroller. The bulk of the apparatus is characterized by a tubular shape with a diameter of 10 mm and a length of 35 mm. The optical system, composed of four lens groups, of which two are mobile, has a total length of 13.46 mm and an effective focal length ranging from 1.61 to 4.44 mm with a zoom factor of 2.75×, with a corresponding angular field of view ranging from 16° to 40°. The mechatronics unit, devoted to move the zoom and the focus lens groups, is implemented adopting miniature piezoelectric motors. The control logics implements a closed-loop mechanism, between the LEDs and photodiode, to attain automatic control light. Bottlenecks of the design and some potential issues of the realization are discussed. A potential clinical scenario is introduced.

  3. Fully Integrated Atmospheric, Surface, and Subsurface Model of the California Basin

    Science.gov (United States)

    Davison, J. H.; Hwang, H. T.; Sudicky, E. A.; Mallia, D. V.; Lin, J. C.

    2016-12-01

    The recent drought in the Western United States has crippled agriculture in California's Central Valley. Farmers, facing reduced surface water flow, have turned to groundwater as their primary solution to the water crisis. However, the unsustainable pumping rates seen throughout California have drastically decreased the surface and subsurface water levels. For this reason, we developed a coupled subsurface, surface, and atmospheric model for the entire California Basin that captures the feedbacks between the three domains at an extremely high spatial and temporal resolution. Our coupled model framework integrates HydroGeoSphere (HGS), a fully implicit three-dimensional control-volume finite element surface and variably saturated subsurface model with evapotranspiration process, to Weather Research and Forecasting (WRF), a three-dimensional mesoscale nonhydrostatic atmospheric model. HGS replaces the land surface component within WRF, and provides WRF with the actual evapotranspiration (AET) and soil saturation. In return, WRF provides HGS with the potential evapotranspiration (PET) and precipitation fluxes. The flexible coupling technique allows HGS and WRF to have unique meshing and projection characteristics and links the domains based on their geographic coordinates (i.e., latitude and longitude). The California Basin model successfully simulated similar drawdown rates to the Gravity Recovery and Climate Experiment (GRACE) and replicated the Klamath and Sacramento River hydrographs. Furthermore, our simulation results reproduced field measured precipitation and evapotranspiration. Currently, our coupled California Basin model is the most complete water resource simulator because we combine the surface, subsurface, and atmosphere into a single domain.

  4. Fully Integrated Passive UHF RFID Tag for Hash-Based Mutual Authentication Protocol.

    Science.gov (United States)

    Mikami, Shugo; Watanabe, Dai; Li, Yang; Sakiyama, Kazuo

    2015-01-01

    Passive radio-frequency identification (RFID) tag has been used in many applications. While the RFID market is expected to grow, concerns about security and privacy of the RFID tag should be overcome for the future use. To overcome these issues, privacy-preserving authentication protocols based on cryptographic algorithms have been designed. However, to the best of our knowledge, evaluation of the whole tag, which includes an antenna, an analog front end, and a digital processing block, that runs authentication protocols has not been studied. In this paper, we present an implementation and evaluation of a fully integrated passive UHF RFID tag that runs a privacy-preserving mutual authentication protocol based on a hash function. We design a single chip including the analog front end and the digital processing block. We select a lightweight hash function supporting 80-bit security strength and a standard hash function supporting 128-bit security strength. We show that when the lightweight hash function is used, the tag completes the protocol with a reader-tag distance of 10 cm. Similarly, when the standard hash function is used, the tag completes the protocol with the distance of 8.5 cm. We discuss the impact of the peak power consumption of the tag on the distance of the tag due to the hash function.

  5. Fully Integrated Passive UHF RFID Tag for Hash-Based Mutual Authentication Protocol

    Directory of Open Access Journals (Sweden)

    Shugo Mikami

    2015-01-01

    Full Text Available Passive radio-frequency identification (RFID tag has been used in many applications. While the RFID market is expected to grow, concerns about security and privacy of the RFID tag should be overcome for the future use. To overcome these issues, privacy-preserving authentication protocols based on cryptographic algorithms have been designed. However, to the best of our knowledge, evaluation of the whole tag, which includes an antenna, an analog front end, and a digital processing block, that runs authentication protocols has not been studied. In this paper, we present an implementation and evaluation of a fully integrated passive UHF RFID tag that runs a privacy-preserving mutual authentication protocol based on a hash function. We design a single chip including the analog front end and the digital processing block. We select a lightweight hash function supporting 80-bit security strength and a standard hash function supporting 128-bit security strength. We show that when the lightweight hash function is used, the tag completes the protocol with a reader-tag distance of 10 cm. Similarly, when the standard hash function is used, the tag completes the protocol with the distance of 8.5 cm. We discuss the impact of the peak power consumption of the tag on the distance of the tag due to the hash function.

  6. A 160 μA biopotential acquisition IC with fully integrated IA and motion artifact suppression.

    Science.gov (United States)

    Van Helleputte, Nick; Kim, Sunyoung; Kim, Hyejung; Kim, Jong Pal; Van Hoof, Chris; Yazicioglu, Refet Firat

    2012-12-01

    This paper proposes a 3-channel biopotential monitoring ASIC with simultaneous electrode-tissue impedance measurements which allows real-time estimation of motion artifacts on each channel using an an external μC. The ASIC features a high performance instrumentation amplifier with fully integrated sub-Hz HPF rejecting rail-to-rail electrode-offset voltages. Each readout channel further has a programmable gain amplifier and programmable 4th order low-pass filter. Time-multiplexed 12 b SAR-ADCs are used to convert all the analog data to digital. The ASIC achieves >; 115 dB of CMRR (at 50/60 Hz), a high input impedance of >; 1 GΩ and low noise (1.3 μVrms in 100 Hz). Unlike traditional methods, the ASIC is capable of actual motion artifact suppression in the analog domain before final amplification. The complete ASIC core operates from 1.2 V with 2 V digital IOs and consumes 200 μW when all 3 channels are active.

  7. Fully integrated low-noise readout circuit with automatic offset cancellation loop for capacitive microsensors.

    Science.gov (United States)

    Song, Haryong; Park, Yunjong; Kim, Hyungseup; Cho, Dong-Il Dan; Ko, Hyoungho

    2015-10-14

    Capacitive sensing schemes are widely used for various microsensors; however, such microsensors suffer from severe parasitic capacitance problems. This paper presents a fully integrated low-noise readout circuit with automatic offset cancellation loop (AOCL) for capacitive microsensors. The output offsets of the capacitive sensing chain due to the parasitic capacitances and process variations are automatically removed using AOCL. The AOCL generates electrically equivalent offset capacitance and enables charge-domain fine calibration using a 10-bit R-2R digital-to-analog converter, charge-transfer switches, and a charge-storing capacitor. The AOCL cancels the unwanted offset by binary-search algorithm based on 10-bit successive approximation register (SAR) logic. The chip is implemented using 0.18 μm complementary metal-oxide-semiconductor (CMOS) process with an active area of 1.76 mm². The power consumption is 220 μW with 3.3 V supply. The input parasitic capacitances within the range of -250 fF to 250 fF can be cancelled out automatically, and the required calibration time is lower than 10 ms.

  8. Fully 3D printed integrated reactor array for point-of-care molecular diagnostics.

    Science.gov (United States)

    Kadimisetty, Karteek; Song, Jinzhao; Doto, Aoife M; Hwang, Young; Peng, Jing; Mauk, Michael G; Bushman, Frederic D; Gross, Robert; Jarvis, Joseph N; Liu, Changchun

    2018-06-30

    Molecular diagnostics that involve nucleic acid amplification tests (NAATs) are crucial for prevention and treatment of infectious diseases. In this study, we developed a simple, inexpensive, disposable, fully 3D printed microfluidic reactor array that is capable of carrying out extraction, concentration and isothermal amplification of nucleic acids in variety of body fluids. The method allows rapid molecular diagnostic tests for infectious diseases at point of care. A simple leak-proof polymerization strategy was developed to integrate flow-through nucleic acid isolation membranes into microfluidic devices, yielding a multifunctional diagnostic platform. Static coating technology was adopted to improve the biocompatibility of our 3D printed device. We demonstrated the suitability of our device for both end-point colorimetric qualitative detection and real-time fluorescence quantitative detection. We applied our diagnostic device to detection of Plasmodium falciparum in plasma samples and Neisseria meningitides in cerebrospinal fluid (CSF) samples by loop-mediated, isothermal amplification (LAMP) within 50 min. The detection limits were 100 fg for P. falciparum and 50 colony-forming unit (CFU) for N. meningitidis per reaction, which are comparable to that of benchtop instruments. This rapid and inexpensive 3D printed device has great potential for point-of-care molecular diagnosis of infectious disease in resource-limited settings. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. A novel optically transparent RF shielding for fully integrated PET/MRI systems

    Science.gov (United States)

    Parl, C.; Kolb, A.; Schmid, A. M.; Wehrl, H. F.; Disselhorst, J. A.; Soubiran, P. D.; Stricker-Shaver, D.; Pichler, B. J.

    2017-09-01

    Preclinical imaging benefits from simultaneous acquisition of high-resolution anatomical and molecular data. Additionally, PET/MRI systems can provide functional PET and functional MRI data. To optimize PET sensitivity, we propose a system design that fully integrates the MRI coil into the PET system. This allows positioning the scintillators near the object but requires an optimized design of the MRI coil and PET detector. It further requires a new approach in realizing the radiofrequency (RF) shielding. Thus, we propose the use of an optically transparent RF shielding material between the PET scintillator and the light sensor, suppressing the interference between both systems. We evaluated two conductive foils (ITO, 9900) and a wire mesh. The PET performance was tested on a dual-layer scintillator consisting of 12  ×  12 LSO matrices, shifted by half a pitch. The pixel size was 0.9  ×  0.9 mm2 the lengths were 10.0 mm and 5.0 mm, respectively. For a light sensor, we used a 4  ×  4 SiPM array. The RF attenuation was measured from 320 kHz to 420 MHz using two pick-up coils. MRI-compatibility and shielding effect of the materials were evaluated with an MRI system. The average FWHM energy resolution at 511 keV of all 144 crystals of the layer next to the SiPM was deteriorated from 15.73  ±  0.24% to 16.32  ±  0.13%, 16.60  ±  0.25%, and 19.16  ±  0.21% by the ITO foil, 9900 foil, mesh material, respectively. The average peak-to-valley ratio of the PET detector changed from 5.77  ±  0.29 to 4.50  ±  0.39, 4.78  ±  0.48, 3.62  ±  0.16, respectively. The ITO, 9900, mesh attenuated the scintillation light by 11.3  ±  1.6%, 11.0  ±  1.8%, 54.3  ±  0.4%, respectively. To attenuate the RF from 20 MHz to 200 MHz, mesh performed better than copper. The results show that an RF shielding material that is sufficiently transparent for

  10. A compact picosecond pulsed laser source using a fully integrated CMOS driver circuit

    Science.gov (United States)

    He, Yuting; Li, Yuhua; Yadid-Pecht, Orly

    2016-03-01

    Picosecond pulsed laser source have applications in areas such as optical communications, biomedical imaging and supercontinuum generation. Direct modulation of a laser diode with ultrashort current pulses offers a compact and efficient approach to generate picosecond laser pulses. A fully integrated complementary metaloxide- semiconductor (CMOS) driver circuit is designed and applied to operate a 4 GHz distributed feedback laser (DFB). The CMOS driver circuit combines sub-circuits including a voltage-controlled ring oscillator, a voltagecontrolled delay line, an exclusive-or (XOR) circuit and a current source circuit. Ultrashort current pulses are generated by the XOR circuit when the delayed square wave is XOR'ed with the original square wave from the on-chip oscillator. Circuit post-layout simulation shows that output current pulses injected into an equivalent circuit load of the laser have a pulse full width at half maximum (FWHM) of 200 ps, a peak current of 80 mA and a repetition rate of 5.8 MHz. This driver circuit is designed in a 0.13 μm CMOS process and taped out on a 0.3 mm2 chip area. This CMOS chip is packaged and interconnected with the laser diode on a printed circuit board (PCB). The optical output waveform from the laser source is captured by a 5 GHz bandwidth photodiode and an 8 GHz bandwidth oscilloscope. Measured results show that the proposed laser source can output light pulses with a pulse FWHM of 151 ps, a peak power of 6.4 mW (55 mA laser peak forward current) and a repetition rate of 5.3 MHz.

  11. A smart fully integrated micromachined separator with soft magnetic micro-pillar arrays for cell isolation

    Science.gov (United States)

    Dong, Tao; Su, Qianhua; Yang, Zhaochu; Zhang, Yulong; Egeland, Eirik B.; Gu, Dan D.; Calabrese, Paolo; Kapiris, Matteo J.; Karlsen, Frank; Minh, Nhut T.; Wang, K.; Jakobsen, Henrik

    2010-11-01

    A smart fully integrated micromachined separator with soft magnetic micro-pillar arrays has been developed and demonstrated, which can merely employ one independent lab-on-chip to realize cell isolation. The simulation, design, microfabrication and test for the new electromagnetic micro separator were executed. The simulation results of the electromagnetic field in the separator show that special soft magnetic micro-pillar arrays can amplify and redistribute the electromagnetic field generated by the micro-coils. The separator can be equipped with a strong magnetic field to isolate the target cells with a considerably low input current. The micro separator was fabricated by micro-processing technology. An electroplating bath was hired to deposit NiCo/NiFe to fabricate the micro-pillar arrays. An experimental system was set up to verify the function of the micro separator by isolating the lymphocytes, in which the human whole blood mixed with Dynabeads® FlowComp Flexi and monoclonal antibody MHCD2704 was used as the sample. The results show that the electromagnetic micro separator with an extremely low input current can recognize and capture the target lymphocytes with a high efficiency, the separation ratio reaching more than 90% at a lower flow rate. For the electromagnetic micro separator, there is no external magnetizing field required, and there is no extra cooling system because there is less Joule heat generated due to the lower current. The magnetic separator is totally reusable, and it can be used to separate cells or proteins with common antigens.

  12. A fully integrated electrochemical biosensor platform fabrication process for cytokines detection.

    Science.gov (United States)

    Baraket, Abdoullatif; Lee, Michael; Zine, Nadia; Sigaud, Monique; Bausells, Joan; Errachid, Abdelhamid

    2017-07-15

    Interleukin-1b (IL-1b) and interleukin-10 (IL-10) biomarkers are one of many antigens that are secreted in acute stages of inflammation after left ventricle assisted device (LVAD) implantation for patients suffering from heart failure (HF). In the present study, we have developed a fully integrated electrochemical biosensor platform for cytokine detection at minute concentrations. Using eight gold working microelectrodes (WEs) the design will increase the sensitivity of detection, decrease the time of measurements, and allow a simultaneous detection of varying cytokine biomarkers. The biosensor platform was fabricated onto silicon substrates using silicon technology. Monoclonal antibodies (mAb) of anti-human IL-1b and anti-human IL-10 were electroaddressed onto the gold WEs through functionalization with 4-carboxymethyl aryl diazonium (CMA). Cyclic voltammetry (CV) was applied during the WE functionalization process to characterize the gold WE surface properties. Finally, electrochemical impedance spectroscopy (EIS) characterized the modified gold WE. The biosensor platform was highly sensitive to the corresponding cytokines and no interference with other cytokines was observed. Both cytokines: IL-10 and IL-1b were detected within the range of 1pgmL -1 to 15pgmL -1 . The present electrochemical biosensor platform is very promising for multi-detection of biomolecules which can dramatically decrease the time of analysis. This can provide data to clinicians and doctors concerning cytokines secretion at minute concentrations and the prediction of the first signs of inflammation after LVAD implantation. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Photosynthetic Entrainment of the Circadian Clock Facilitates Plant Growth under Environmental Fluctuations: Perspectives from an Integrated Model of Phase Oscillator and Phloem Transportation

    Directory of Open Access Journals (Sweden)

    Takayuki Ohara

    2017-10-01

    Full Text Available Plants need to avoid carbon starvation and resultant growth inhibition under fluctuating light environments to ensure optimal growth and reproduction. As diel patterns of carbon metabolism are influenced by the circadian clock, appropriate regulation of the clock is essential for plants to properly manage their carbon resources. For proper adjustment of the circadian phase, higher plants utilize environmental signals such as light or temperature and metabolic signals such as photosynthetic products; the importance of the latter as phase regulators has been recently elucidated. A mutant of Arabidopsis thaliana that is deficient in phase response to sugar has been shown, under fluctuating light conditions, to be unable to adjust starch turnover and to realize carbon homeostasis. Whereas, the effects of light entrainment on growth and survival of higher plants are well studied, the impact of phase regulation by sugar remains unknown. Here we show that endogenous sugar entrainment facilitates plant growth. We integrated two mathematical models, one describing the dynamics of carbon metabolism in A. thaliana source leaves and the other growth of sink tissues dependent on sucrose translocation from the source. The integrated model predicted that sugar-sensitive plants grow faster than sugar-insensitive plants under constant as well as changing photoperiod conditions. We found that sugar entrainment enables efficient carbon investment for growth by stabilizing sucrose supply to sink tissues. Our results highlight the importance of clock entrainment by both exogenous and endogenous signals for optimizing growth and increasing fitness.

  14. I-RaCM: A Fully Integrated Risk and Lifecycle Cost Model, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SpaceWorks Engineering, Inc. (SEI) proposes development of the Integrated Risk and Cost Model I-RaCM, as the innovation to meet the need for integrated cost and risk...

  15. Dynamic Power Reduction of Digital Circuits by ClockGating

    OpenAIRE

    Varsha Dewre; Rakesh Mandliya

    2017-01-01

    In this paper we have presented clock gating process for low power VLSI (very large scale integration) circuit design. Clock gating is one of the most quite often used systems in RTL to shrink dynamic power consumption without affecting the performance of the design. One process involves inserting gating requisites in the RTL, which the synthesis tool translates to clock gating cells in the clock-path of a register bank. This helps to diminish the switching activity on the clock network, ther...

  16. SmartStep: A Fully Integrated, Low-Power Insole Monitor

    OpenAIRE

    Nagaraj Hegde; Edward Sazonov

    2014-01-01

    Shoe-mounted wearable sensors can be used in applications, such as activity monitoring, gait analysis, post-stroke rehabilitation, body weight measurements and energy expenditure studies. Such wearable sensors typically require the modification or alteration of the shoe, which is not typically feasible for large populations without the direct involvement of shoe manufacturers. This article presents an insole-based wearable sensor (SmartStep) that has its electronics fully embedded into a gene...

  17. A fully integrated, monolithic, cryogenic charge sensitive preamplifier using N-channel JFETs and polysilicon resistors

    International Nuclear Information System (INIS)

    Jung, T.S.; Guckel, H.; Seefeldt, J.; Ott, G.; Ahn, Y.C.

    1994-01-01

    In this paper, an integrated charge preamplifier to be used with small (10--30 mm 2 ) Si(Li) and Ge(Li) X-ray detectors is described. The preamplifier is designed to operate at cryogenic temperatures (∼100 K to 160 K) for the best performance. An N-channel JFET process technology for integrated charge sensitive preamplifiers has been developed. The process integrates multiple pinch-off voltage JFETs fabricated in an n-type epitaxial layer on a low resistivity p-type substrate. The process also incorporates polysilicon resistors integrated on the same die as the JFETs. The optimized polysilicon resistors exhibit 1/f noise nearly as good as metal film resistors at the same current. Results for integrated amplifier are discussed

  18. Engineering Engine/Airframe Integration for Fully Reusable Space Transportation Systems

    Science.gov (United States)

    2010-09-01

    Conception du moteur - integration et gestion thermique ) 14. ABSTRACT In the late 80ties and 90ties many programs were initiated in US, Russia, Japan and...major time frames. At the end, mainly to shortcomings of the national budget, the program was transferred as a starting point to an ESA initiated

  19. The Engineering Design of Engine/Airframe Integration for the SAENGER Fully Reusable Space Transportation System

    Science.gov (United States)

    2010-09-01

    elevee : Conception du moteur - integration et gestion thermique ) 14. ABSTRACT In Germany the Ministry of Research and Technology (BMFT) initiated in...national budget, the program was transferred as a starting point to an ESA initiated international European program named FESTIP (Future European Space

  20. Fully integrated micro coriolis mass flow sensor operating at atmospheric pressure

    NARCIS (Netherlands)

    Lötters, Joost Conrad; Lammerink, Theodorus S.J.; Haneveld, J.; Hageman, Tijmen Antoon Geert; Hageman, Tijmen A.G.; Wiegerink, Remco J.

    2012-01-01

    This paper discusses the design and realization of a micromachined micro Coriolis flow sensor with integrated electrodes for both electrostatic actuation and capacitive readout. The sensor was realized using semicircular channels just beneath the surface of the silicon wafer. The channels have thin

  1. Fully Integrated Micro Coriolis Mass Flow Sensor Operating at Atmospheric Pressure

    NARCIS (Netherlands)

    Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Haneveld, J.; Hageman, T.A.G.; Hageman, Tijmen Antoon Geert; Lötters, Joost Conrad

    This paper discusses the design and realization of a micromachined micro Coriolis flow sensor with integrated electrodes for both electrostatic actuation and capacitive readout. The sensor was realized using semicircular channels just beneath the surface of the silicon wafer. The channels have thin

  2. Fully integrated optical system for lab-on-a-chip applications

    DEFF Research Database (Denmark)

    Balslev, Søren; Olsen, Brian Bilenberg; Geschke, Oliver

    2004-01-01

    We present a lab-on-a-chip device featuring a microfluidic dye laser, wave-guides, microfluidic components and photo-detectors integrated on the chip. The microsystem is designed for wavelength selective absorption measurements in the visible range on a fluidic sample, which can be prepared/mixed...

  3. Toward a fully integrated wireless wearable EEG-NIRS bimodal acquisition system

    Science.gov (United States)

    Safaie, J.; Grebe, R.; Abrishami Moghaddam, H.; Wallois, F.

    2013-10-01

    Objective. Interactions between neuronal electrical activity and regional changes in microcirculation are assumed to play a major role in physiological brain activity and the development of pathological disorders, but have been poorly elucidated to date. There is a need for advanced diagnostic tools to investigate the relationships between these two physiological processes.Approach. To meet these needs, a wireless wearable system has been developed, which combines a near infrared spectroscopy (NIRS) system using light emitting diodes (LEDs) as a light source and silicon photodiodes as a detector with an integrated electroencephalography (EEG) system. Main results. The main advantages over currently available devices are miniaturization and integration of a real-time electrical and hemodynamic activity monitor into one wearable device. For patient distributed monitoring and creating a body-area network, up to seven same devices can be connected to a single base station (PC) synchronously. Each node presents enhanced portability due to the wireless communication and highly integrated components resulting in a small, lightweight signal acquisition device. Further progress includes the individual control of LEDs output to automatically or interactively adjust emitted light to the actual local situation online, the use of silicon photodiodes with a safe low-voltage power supply, and an integrated three dimensional accelerometer for movement detection for the identification of motion artifacts. Significance. The device was tested and validated using our enhanced EEG-NIRS tissue mimicking fluid phantom for sensitivity mapping. Typical somatotopic electrical evoked potential experiments were performed to verify clinical applicability.

  4. Performance and safety of an integrated bihormonal artificial pancreas for fully automated glucose control at home

    NARCIS (Netherlands)

    Blauw, H.; van Bon, A. C.; Koops, R.; DeVries, J. H.

    2016-01-01

    To assess the performance and safety of an integrated bihormonal artificial pancreas system consisting of one wearable device and two wireless glucose sensor transmitters during short-term daily use at home. Adult patients with type 1 diabetes using an insulin pump were invited to enrol in this

  5. A fully analytical integration of properties over the 3D volume of the β sphere in topological atoms

    Science.gov (United States)

    2018-01-01

    Atomic multipole moments associated with a spherical volume fully residing within a topological atom (i.e., the β sphere) can be obtained analytically. Such an integration is thus free of quadrature grids. A general formula for an arbitrary rank spherical harmonic multipole moment is derived, for an electron density comprising Gaussian primitives of arbitrary angular momentum. The closed expressions derived here are also sufficient to calculate the electrostatic potential, the two types of kinetic energy, as well as the potential energy between atoms. Some integrals have not been solved explicitly before but through recursion and substitution are broken down to more elementary listed integrals. The proposed method is based on a central formula that shifts Gaussian primitives from one center to another, which can be derived from the well‐known plane‐wave expansion (or Rayleigh equation). © 2018 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc. PMID:29322516

  6. Ultrasensitive mass sensor fully integrated with complementary metal-oxide-semiconductor circuitry

    DEFF Research Database (Denmark)

    Forsén, Esko Sebastian; Abadal, G.; Ghatnekar-Nilsson, S.

    2005-01-01

    Nanomechanical resonators have been monolithically integrated on preprocessed complementary metal-oxide-semiconductor (CMOS) chips. Fabricated resonator systems have been designed to have resonance frequencies up to 1.5 MHz. The systems have been characterized in ambient air and vacuum conditions...... and display ultrasensitive mass detection in air. A mass sensitivity of 4 ag/Hz has been determined in air by placing a single glycerine drop, having a measured weight of 57 fg, at the apex of a cantilever and subsequently measuring a frequency shift of 14.8 kHz. CMOS integration enables electrostatic...... excitation, capacitive detection, and amplification of the resonance signal directly on the chip. (c) 2005 American Institute of Physics....

  7. Fully integrated monolithic opoelectronic transducer for real.time protein and DNA detection

    DEFF Research Database (Denmark)

    Misiakos, Konstatinos; S. Petrou, Panagiota; E. Kakabakos, Sotirios

    2010-01-01

    The development and testing of a portable bioanalytical device which was capable for real-time monitoring of binding assays was demonstrated. The device was based on arrays of nine optoelectronic transducers monolithically integrated on silicon chips. The optocouplers consisted of nine silicon...... by exploiting wavelength filtering on photonic crystal engineered waveguides. The proposed miniaturized sensing device with proper packaging and accompanied by a portable instrument can find wide application as a platform for reliable and cost effective point-of-care diagnosis....

  8. Fully Integrated Applications of Thin Films on Low Temperature Cofired Ceramic (LTCC)

    Energy Technology Data Exchange (ETDEWEB)

    Ambrose Wolf; Ken Peterson; Matt O' Keefe; Wayne Huebner; Bill Kuhn

    2012-04-19

    Thin film multilayers have previously been introduced on multilayer low temperature cofired ceramic (LTCC), as well as initial thin film capacitors on LTCC. The ruggedness of a multipurpose Ti-Cu-Pt-Au stack for connectivity and RF conductivity has continued to benefit fabrication and reliability in state of-the-art modules, while the capacitors have followed the traditional Metal-Insulator-Metal (MIM) style. The full integration of thin film passives with thin film connectivity traces is presented. Certain passives, such as capacitors, require specifically tailored and separately patterned thin film (multi-)layers, including a dielectric. Different capacitance values are achieved by variation of both the insulator layer thickness and the active area of the capacitor. Other passives, such as filters, require only the conductor - a single thin film multilayer. This can be patterned from the same connectivity thin film material (Ti-Cu-Pt-Au), or a specially tailored thin film material (e.g. Ti-Cu-Au) can be deposited. Both versions are described, including process and integration details. Examples are discussed, ranging from patterning for maximum tolerances, to space and performance-optimized designs. Cross-sectional issues associated with integration are also highlighted in the discussion.

  9. Fully Integrated, Miniature, High-Frequency Flow Probe Utilizing MEMS Leadless SOI Technology

    Science.gov (United States)

    Ned, Alex; Kurtz, Anthony; Shang, Tonghuo; Goodman, Scott; Giemette. Gera (d)

    2013-01-01

    This work focused on developing, fabricating, and fully calibrating a flowangle probe for aeronautics research by utilizing the latest microelectromechanical systems (MEMS), leadless silicon on insulator (SOI) sensor technology. While the concept of angle probes is not new, traditional devices had been relatively large due to fabrication constraints; often too large to resolve flow structures necessary for modern aeropropulsion measurements such as inlet flow distortions and vortices, secondary flows, etc. Mea surements of this kind demanded a new approach to probe design to achieve sizes on the order of 0.1 in. (.3 mm) diameter or smaller, and capable of meeting demanding requirements for accuracy and ruggedness. This approach invoked the use of stateof- the-art processing techniques to install SOI sensor chips directly onto the probe body, thus eliminating redundancy in sensor packaging and probe installation that have historically forced larger probe size. This also facilitated a better thermal match between the chip and its mount, improving stability and accuracy. Further, the leadless sensor technology with which the SOI sensing element is fabricated allows direct mounting and electrical interconnecting of the sensor to the probe body. This leadless technology allowed a rugged wire-out approach that is performed at the sensor length scale, thus achieving substantial sensor size reductions. The technology is inherently capable of high-frequency and high-accuracy performance in high temperatures and harsh environments.

  10. High-precision high-sensitivity clock recovery circuit for a mobile payment application

    International Nuclear Information System (INIS)

    Sun Lichong; Yan Na; Min Hao; Ren Wenliang

    2011-01-01

    This paper presents a fully integrated carrier clock recovery circuit for a mobile payment application. The architecture is based on a sampling-detection module and a charge pump phase locked loop. Compared with clock recovery in conventional 13.56 MHz transponders, this circuit can recover a high-precision consecutive carrier clock from the on/off keying (OOK) signal sent by interrogators. Fabricated by a SMIC 0.18-μm EEPROM CMOS process, this chip works from a single power supply as low as 1.5 V Measurement results show that this circuit provides 0.34% frequency deviation and 8 mV sensitivity. (semiconductor integrated circuits)

  11. Synthesis and design of a fully integrated multi-topology switched capacitor DC-DC converter with gearbox control

    DEFF Research Database (Denmark)

    Davidsen, Jeppe Gaardsted; Yosef-Hay, Yoni; Larsen, Dennis Øland

    2017-01-01

    approach is presented with all the required circuits. The converter is able to generate a output voltage of 1.2 V from a 470 mF capacitor charged to 3 V down to 1.4 V. The output voltage is regulated with a ripple voltage below 7 mV. The controlling circuit including buffers with ideal comparators has......This paper discusses a methodology of minimizing the amount of switches in a multi-topology fully integrated switched capacitor dc-dc converter powered by a super capacitor for energy harvesting purposes. The design of a simple controlling circuit for the multi-topology power stage using a gearbox...

  12. Fully Integrated, Low Drop-Out Linear Voltage Regulator in 180 nm CMOS

    DEFF Research Database (Denmark)

    Yosef-Hay, Yoni; Larsen, Dennis Øland; Llimos Muntal, Pere

    2017-01-01

    This paper presents a capacitor-free low dropout (LDO) linear regulator based on a dual loop topology. The regulator utilizes two feedback loops to satisfy the challenges of hearing aid devices, which include fast transient performance and small voltage spikes under rapid load-current changes....... The proposed design works without the need of a decoupling capacitor connected at the output and operates with a 0-100 pF capacitive load. The design has been taped out in a 0.18 µm CMOS process. The proposed regulator has a low component count, area of 0.012 mm2 and is suitable for system-on-chip integration...

  13. SmartStep: A Fully Integrated, Low-Power Insole Monitor

    Directory of Open Access Journals (Sweden)

    Nagaraj Hegde

    2014-06-01

    Full Text Available Shoe-mounted wearable sensors can be used in applications, such as activity monitoring, gait analysis, post-stroke rehabilitation, body weight measurements and energy expenditure studies. Such wearable sensors typically require the modification or alteration of the shoe, which is not typically feasible for large populations without the direct involvement of shoe manufacturers. This article presents an insole-based wearable sensor (SmartStep that has its electronics fully embedded into a generic insole, which is usable with a large variety of shoes and, thus, resolves the need for shoe modification. The SmartStep is an always-on electronic device that comprises a 3D accelerometer, a 3D gyroscope and resistive pressure sensors implemented around a CC2540 system-on-chip with an 8051 processor core, Bluetooth low energy (BLE connectivity and flash memory buffer. The SmartStep is wirelessly interfaced to an Android smart phone application with data logging and visualization capabilities. This article focuses on low-power implementation methods and on the method developed for reliable data buffering, alleviating intermittent connectivity resulting from the user leaving the vicinity of the smart phone. The conducted tests illustrate the power consumption for several possible usage scenarios and the reliability of the data retention method. The trade-off between the power consumption and supported functionality is discussed, demonstrating that SmartStep can be worn for more than two days between battery recharges. The results of the mechanical reliability test on the SmartStep indicate that the pressure sensors in the SmartStep tolerated prolonged human wear. The SmartStep system collected more than 98.5% of the sensor data, in real usage scenarios, having intermittent connectivity with the smart phone.

  14. Fully printed and integrated electrolyzer cells with additive manufacturing for high-efficiency water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Gaoqiang; Mo, Jingke; Kang, Zhenye; Dohrmann, Yeshi; List, Frederick A.; Green, Johney B.; Babu, Sudarsanam S.; Zhang, Feng-Yuan

    2018-04-01

    Using additive manufacturing (AM) technology, a fundamental material and structure innovation was proposed to significantly increase the energy efficiency, and to reduce the weight, volume and component quantity of proton exchange membrane electrolyzer cells (PEMECs). Four conventional parts (liquid/gas diffusion layer, bipolar plate, gasket, and current distributor) in a PEMEC were integrated into one multifunctional AM plate without committing to tools or molds for the first time. In addition, since the interfacial contact resistances between those parts were eliminated, the comprehensive in-situ characterizations of AM cells showed that an excellent energy efficiency of up to 86.48% was achieved at 2 A/cm2 and 80 degrees C, and the hydrogen generation rate was increased by 61.81% compared to the conventional cell. More importantly, the highly complex inner structures of the AM integrated multifunctional plates also exhibit the potential to break limitations of conventional manufacture methods for hydrogen generation and to open a door for the development of other energy conversion devices, including fuel cells, solar cells and batteries.

  15. Novel transcriptional networks regulated by CLOCK in human neurons.

    Science.gov (United States)

    Fontenot, Miles R; Berto, Stefano; Liu, Yuxiang; Werthmann, Gordon; Douglas, Connor; Usui, Noriyoshi; Gleason, Kelly; Tamminga, Carol A; Takahashi, Joseph S; Konopka, Genevieve

    2017-11-01

    The molecular mechanisms underlying human brain evolution are not fully understood; however, previous work suggested that expression of the transcription factor CLOCK in the human cortex might be relevant to human cognition and disease. In this study, we investigated this novel transcriptional role for CLOCK in human neurons by performing chromatin immunoprecipitation sequencing for endogenous CLOCK in adult neocortices and RNA sequencing following CLOCK knockdown in differentiated human neurons in vitro. These data suggested that CLOCK regulates the expression of genes involved in neuronal migration, and a functional assay showed that CLOCK knockdown increased neuronal migratory distance. Furthermore, dysregulation of CLOCK disrupts coexpressed networks of genes implicated in neuropsychiatric disorders, and the expression of these networks is driven by hub genes with human-specific patterns of expression. These data support a role for CLOCK-regulated transcriptional cascades involved in human brain evolution and function. © 2017 Fontenot et al.; Published by Cold Spring Harbor Laboratory Press.

  16. A 135-mW Fully Integrated Data Processor for Next-Generation Sequencing.

    Science.gov (United States)

    Wu, Yi-Chung; Chang, Chia-Hua; Hung, Jui-Hung; Yang, Chia-Hsiang

    2017-12-01

    Next-generation sequencing (NGS) enables high-throughput sequencing, in which short DNA fragments can be sequenced in a massively parallel fashion. However, the essential algorithm behind the succeeding NGS data analysis, DNA mapping, is still excessively time consuming. DNA mapping can be partitioned into two parts: suffix array (SA) sorting and backward searching. Dedicated hardware designs for the less-complex backward searching have been proposed, but feasible hardware for the most complicated part, SA sorting, has never been explored. Based on the memory-efficient sBWT algorithm, this work is the first integrated NGS data processor for the entire DNA mapping. The -ordered Ferragina and Manzini index used in the sBWT algorithm is leveraged to improve storage capacity and reduce hardware complexity. The proposed NGS data processor realizes the sBWT algorithm through bucket sorting, suffix grouping, and suffix sorting circuits. Key design parameters are analyzed to achieve the optimal performance with respect to hardware cost and execution time. Fabricated in 40-nm CMOS, the NGS data processor dissipates 135 mW at 200 MHz from a 0.9-V supply. With 1-GB external memory, the chip can analyze human DNA within 10 min. This work achieves 43 065 and 8 971 [3208 and 402 ] higher energy efficiency (throughput-to-area ratio) than the high-end CPU and GPU solutions, respectively.

  17. Fully integrated multiplexed lab-on-a-card assay for enteric pathogens

    Science.gov (United States)

    Weigl, B. H.; Gerdes, J.; Tarr, P.; Yager, P.; Dillman, L.; Peck, R.; Ramachandran, S.; Lemba, M.; Kokoris, M.; Nabavi, M.; Battrell, F.; Hoekstra, D.; Klein, E. J.; Denno, D. M.

    2006-01-01

    Under this NIH-funded project, we are developing a lab-on-a-card platform to identify enteric bacterial pathogens in patients presenting with acute diarrhea, with special reference to infections that might be encountered in developing countries. Component functions that are integrated on this platform include on-chip immunocapture of live or whole pathogens, multiplexed nucleic acid amplification and on-chip detection, sample processing to support direct use of clinical specimens, and dry reagent storage and handling. All microfluidic functions are contained on the lab card. This new diagnostic test will be able to rapidly identify and differentiate Shigella dysenteriae serotype 1, Shigella toxin-producing Escherichia coli, E. coli 0157, Campylobacter jejuni, and Salmonella and Shigella species. This presentation will report on progress to date on sample and bacteria processing methodologies, identification and validation of capture antibodies and strategy for organism immunocapture, identification and validation of specific polymerase chain reaction (PCR) primer sequences for over 200 clinical isolates of enteric pathogens, and implementation of on-chip nucleic acid extraction for a subset of those pathogens.

  18. Microfluidics & nanotechnology: Towards fully integrated analytical devices for the detection of cancer biomarkers

    KAUST Repository

    Perozziello, Gerardo

    2014-01-01

    In this paper, we describe an innovative modular microfluidic platform allowing filtering, concentration and analysis of peptides from a complex mixture. The platform is composed of a microfluidic filtering device and a superhydrophobic surface integrating surface enhanced Raman scattering (SERS) sensors. The microfluidic device was used to filter specific peptides (MW 1553.73 D) derived from the BRCA1 protein, a tumor-suppressor molecule which plays a pivotal role in the development of breast cancers, from albumin (66.5 KD), the most represented protein in human plasma. The filtering process consisted of driving the complex mixture through a porous membrane having a cut-off of 12-14 kD by hydrodynamic flow. The filtered samples coming out of the microfluidic device were subsequently deposited on a superhydrophobic surface formed by micro pillars on top of which nanograins were fabricated. The nanograins coupled to a Raman spectroscopy instrument acted as a SERS sensor and allowed analysis of the filtered sample on top of the surface once it evaporated. By using the presented platform, we demonstrate being able to sort small peptides from bigger proteins and to detect them by using a label-free technique at a resolution down to 0.1 ng μL-1. The combination of microfluidics and nanotechnology to develop the presented microfluidic platform may give rise to a new generation of biosensors capable of detecting low concentration samples from complex mixtures without the need for any sample pretreatment or labelling. The developed devices could have future applications in the field of early diagnosis of severe illnesses, e.g. early cancer detection. This journal is

  19. SEMICONDUCTOR INTEGRATED CIRCUITS: An advanced monolithic digitalized random carrier frequency spread-spectrum clock generator for EMI suppression

    Science.gov (United States)

    Haiyan, Guo; Zao, Chen; Bo, Zhang; Zhaoji, Li

    2010-06-01

    A novel monolithic digitalized random carrier frequency modulation spread-spectrum clock generator (RCF-SSCG) is proposed. In this design, the output frequency of the proposed RCF-SSCG changes with the intensity of the capacitive charge and discharge current. Its analytical model is induced and the effect of the modulation parameters on the spread spectrum is numerically simulated and discussed. Compared with other works, this design has the advantages of small size, low power consumption and good robustness. The circuit has been fabricated in a 0.5 μm CMOS process and applied to a class D amplifier in which the proposed RCF-SSCG occupies an area of 0.112 mm2 and consumes 9 mW. The experimental results confirm the theoretical analyses.

  20. Fully Quantum Description of the Zundel Ion: Combining Variational Quantum Monte Carlo with Path Integral Langevin Dynamics.

    Science.gov (United States)

    Mouhat, Félix; Sorella, Sandro; Vuilleumier, Rodolphe; Saitta, Antonino Marco; Casula, Michele

    2017-06-13

    We introduce a novel approach for a fully quantum description of coupled electron-ion systems from first principles. It combines the variational quantum Monte Carlo solution of the electronic part with the path integral formalism for the quantum nuclear dynamics. On the one hand, the path integral molecular dynamics includes nuclear quantum effects by adding a set of fictitious classical particles (beads) aimed at reproducing nuclear quantum fluctuations via a harmonic kinetic term. On the other hand, variational quantum Monte Carlo can provide Born-Oppenheimer potential energy surfaces with a precision comparable to the most-advanced post-Hartree-Fock approaches, and with a favorable scaling with the system size. In order to cope with the intrinsic noise due to the stochastic nature of quantum Monte Carlo methods, we generalize the path integral molecular dynamics using a Langevin thermostat correlated according to the covariance matrix of quantum Monte Carlo nuclear forces. The variational parameters of the quantum Monte Carlo wave function are evolved during the nuclear dynamics, such that the Born-Oppenheimer potential energy surface is unbiased. Statistical errors on the wave function parameters are reduced by resorting to bead grouping average, which we show to be accurate and well-controlled. Our general algorithm relies on a Trotter breakup between the dynamics driven by ionic forces and the one set by the harmonic interbead couplings. The latter is exactly integrated, even in the presence of the Langevin thermostat, thanks to the mapping onto an Ornstein-Uhlenbeck process. This framework turns out to be also very efficient in the case of noiseless (deterministic) ionic forces. The new implementation is validated on the Zundel ion (H 5 O 2 + ) by direct comparison with standard path integral Langevin dynamics calculations made with a coupled cluster potential energy surface. Nuclear quantum effects are confirmed to be dominant over thermal effects well

  1. TAPINS: A THERMAL-HYDRAULIC SYSTEM CODE FOR TRANSIENT ANALYSIS OF A FULLY-PASSIVE INTEGRAL PWR

    Directory of Open Access Journals (Sweden)

    YEON-GUN LEE

    2013-08-01

    Full Text Available REX-10 is a fully-passive small modular reactor in which the coolant flow is driven by natural circulation, the RCS is pressurized by a steam-gas pressurizer, and the decay heat is removed by the PRHRS. To confirm design decisions and analyze the transient responses of an integral PWR such as REX-10, a thermal-hydraulic system code named TAPINS (Thermal-hydraulic Analysis Program for INtegral reactor System is developed in this study. Based on a one-dimensional four-equation drift-flux model, TAPINS incorporates mathematical models for the core, the helical-coil steam generator, and the steam-gas pressurizer. The system of difference equations derived from the semi-implicit finite-difference scheme is numerically solved by the Newton Block Gauss Seidel (NBGS method. TAPINS is characterized by applicability to transients with non-equilibrium effects, better prediction of the transient behavior of a pressurizer containing non-condensable gas, and code assessment by using the experimental data from the autonomous integral effect tests in the RTF (REX-10 Test Facility. Details on the hydrodynamic models as well as a part of validation results that reveal the features of TAPINS are presented in this paper.

  2. Z n clock models and chains of so(n)2 non-Abelian anyons: symmetries, integrable points and low energy properties

    Science.gov (United States)

    Finch, Peter E.; Flohr, Michael; Frahm, Holger

    2018-02-01

    We study two families of quantum models which have been used previously to investigate the effect of topological symmetries in one-dimensional correlated matter. Various striking similarities are observed between certain {Z}n quantum clock models, spin chains generalizing the Ising model, and chains of non-Abelian anyons constructed from the so(n)2 fusion category for odd n, both subject to periodic boundary conditions. In spite of the differences between these two types of quantum chains, e.g. their Hilbert spaces being spanned by tensor products of local spin states or fusion paths of anyons, the symmetries of the lattice models are shown to be closely related. Furthermore, under a suitable mapping between the parameters describing the interaction between spins and anyons the respective Hamiltonians share part of their energy spectrum (although their degeneracies may differ). This spin-anyon correspondence can be extended by fine-tuning of the coupling constants leading to exactly solvable models. We show that the algebraic structures underlying the integrability of the clock models and the anyon chain are the same. For n  =  3,5,7 we perform an extensive finite size study—both numerical and based on the exact solution—of these models to map out their ground state phase diagram and to identify the effective field theories describing their low energy behaviour. We observe that the continuum limit at the integrable points can be described by rational conformal field theories with extended symmetry algebras which can be related to the discrete ones of the lattice models.

  3. Micro-patterning of resin-bonded NdFeB magnet for a fully integrated electromagnetic actuator

    Science.gov (United States)

    Tao, Kai; Wu, Jin; Kottapalli, Ajay Giri Prakash; Chen, Di; Yang, Zhuoqing; Ding, Guifu; Lye, Sun Woh; Miao, Jianmin

    2017-12-01

    This paper reports a fully-integrated, batch-fabricated electromagnetic actuator which features micro-patterned NdFeB magnets. The entire actuator is fabricated through MEMS-compatible laminated surface micromachining technology, eliminating the requirement for further component assembly processes. The fabrication strategy allowed the entire volume of the actuator to be reduced to a small size of 2.5 × 2.5 × 2 mm3, which is one of the smallest NdFeB-based electromagnetic actuators demonstrated to date. The magnetic properties of NdFeB thin films are further investigated and optimized using different types of lithographically-defined micromolds. By altering the direction of the input current, actuating displacements of approximately ±10 μm are achieved during both the attraction and the repulsion operations. This work demonstrates the viability and compatibility of using polymer-bonded magnets for magnetic MEMS applications.

  4. Analytical bending solution of fully clamped orthotropic rectangular plates resting on elastic foundations by the finite integral transform method

    Directory of Open Access Journals (Sweden)

    Ali Mohammad Moniri Bidgoli

    2015-04-01

    Full Text Available This study presents exact bending solution of fully clamped orthotropic rectangular plates subjected to arbitrary loads resting on elastic foundations, based on the finite integral transform method. In this method, it is not necessary to determine the deformation function because the basic governing equations of the classical plate theory for orthotropic plates have been used. A detailed parametric study is conducted to elucidate the influences of stiffness of elastic medium, plate length, flexural rigidities and distributed transverse load on the deflections. The applicability of the method is extensive since it can solve any plates with different loadings. Numerical results are presented to demonstrate the validity and accuracy of the approach, as it is totally in agreement with the other studies.

  5. Single-Chip Fully Integrated Direct-Modulation CMOS RF Transmitters for Short-Range Wireless Applications

    Directory of Open Access Journals (Sweden)

    M. Jamal Deen

    2013-08-01

    Full Text Available Ultra-low power radio frequency (RF transceivers used in short-range application such as wireless sensor networks (WSNs require efficient, reliable and fully integrated transmitter architectures with minimal building blocks. This paper presents the design, implementation and performance evaluation of single-chip, fully integrated 2.4 GHz and 433 MHz RF transmitters using direct-modulation power voltage-controlled oscillators (PVCOs in addition to a 2.0 GHz phase-locked loop (PLL based transmitter. All three RF transmitters have been fabricated in a standard mixed-signal CMOS 0.18 µm technology. Measurement results of the 2.4 GHz transmitter show an improvement in drain efficiency from 27% to 36%. The 2.4 GHz and 433 MHz transmitters deliver an output power of 8 dBm with a phase noise of −122 dBc/Hz at 1 MHz offset, while drawing 15.4 mA of current and an output power of 6.5 dBm with a phase noise of −120 dBc/Hz at 1 MHz offset, while drawing 20.8 mA of current from 1.5 V power supplies, respectively. The PLL transmitter delivers an output power of 9 mW with a locking range of 128 MHz and consumes 26 mA from 1.8 V power supply. The experimental results demonstrate that the RF transmitters can be efficiently used in low power WSN applications.

  6. High Performance Clocks and Gravity Field Determination

    Science.gov (United States)

    Müller, J.; Dirkx, D.; Kopeikin, S. M.; Lion, G.; Panet, I.; Petit, G.; Visser, P. N. A. M.

    2018-02-01

    Time measured by an ideal clock crucially depends on the gravitational potential and velocity of the clock according to general relativity. Technological advances in manufacturing high-precision atomic clocks have rapidly improved their accuracy and stability over the last decade that approached the level of 10^{-18}. This notable achievement along with the direct sensitivity of clocks to the strength of the gravitational field make them practically important for various geodetic applications that are addressed in the present paper. Based on a fully relativistic description of the background gravitational physics, we discuss the impact of those highly-precise clocks on the realization of reference frames and time scales used in geodesy. We discuss the current definitions of basic geodetic concepts and come to the conclusion that the advances in clocks and other metrological technologies will soon require the re-definition of time scales or, at least, clarification to ensure their continuity and consistent use in practice. The relative frequency shift between two clocks is directly related to the difference in the values of the gravity potential at the points of clock's localization. According to general relativity the relative accuracy of clocks in 10^{-18} is equivalent to measuring the gravitational red shift effect between two clocks with the height difference amounting to 1 cm. This makes the clocks an indispensable tool in high-precision geodesy in addition to laser ranging and space geodetic techniques. We show how clock measurements can provide geopotential numbers for the realization of gravity-field-related height systems and can resolve discrepancies in classically-determined height systems as well as between national height systems. Another application of clocks is the direct use of observed potential differences for the improved recovery of regional gravity field solutions. Finally, clock measurements for space-borne gravimetry are analyzed along with

  7. A Fully Integrated Wireless Compressed Sensing Neural Signal Acquisition System for Chronic Recording and Brain Machine Interface.

    Science.gov (United States)

    Liu, Xilin; Zhang, Milin; Xiong, Tao; Richardson, Andrew G; Lucas, Timothy H; Chin, Peter S; Etienne-Cummings, Ralph; Tran, Trac D; Van der Spiegel, Jan

    2016-07-18

    Reliable, multi-channel neural recording is critical to the neuroscience research and clinical treatment. However, most hardware development of fully integrated, multi-channel wireless neural recorders to-date, is still in the proof-of-concept stage. To be ready for practical use, the trade-offs between performance, power consumption, device size, robustness, and compatibility need to be carefully taken into account. This paper presents an optimized wireless compressed sensing neural signal recording system. The system takes advantages of both custom integrated circuits and universal compatible wireless solutions. The proposed system includes an implantable wireless system-on-chip (SoC) and an external wireless relay. The SoC integrates 16-channel low-noise neural amplifiers, programmable filters and gain stages, a SAR ADC, a real-time compressed sensing module, and a near field wireless power and data transmission link. The external relay integrates a 32 bit low-power microcontroller with Bluetooth 4.0 wireless module, a programming interface, and an inductive charging unit. The SoC achieves high signal recording quality with minimized power consumption, while reducing the risk of infection from through-skin connectors. The external relay maximizes the compatibility and programmability. The proposed compressed sensing module is highly configurable, featuring a SNDR of 9.78 dB with a compression ratio of 8×. The SoC has been fabricated in a 180 nm standard CMOS technology, occupying 2.1 mm × 0.6 mm silicon area. A pre-implantable system has been assembled to demonstrate the proposed paradigm. The developed system has been successfully used for long-term wireless neural recording in freely behaving rhesus monkey.

  8. 3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer †

    Science.gov (United States)

    Asano, Sho; Nakayama, Takahiro; Hata, Yoshiyuki; Tanaka, Shuji

    2017-01-01

    This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D)-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively. PMID:29068429

  9. A fully integrated, low noise and low power BiCMOS front-end readout system for capacitive detectors

    CERN Document Server

    Guo, C C; Deptuch, G; Hu, Y Y

    2001-01-01

    Bipolar transistors are interesting for low noise front-end readout systems when high speed and low power consumption are required. This paper presents a fully integrated, low noise front-end design for the future Large Hadron Collider (LHC) experiments using the radiation hard SOI BiCMOS process. In the present prototype, the input-referred Equivalent Noise Charge (ENC) of 990 electrons (r.m.s.) for 12 pF detector capacitance with a shaping time of 25 ns and power consumption of 1.4 mW/channel has been measured. The gain of this front-end is 90 mV/MIP (Minimum Ionisation Particle: 1 MIP=3.84 fC) with non-linearity of less than 3% and linear input dynamic range is +or-5 MIP. These results are obtained at room temperature and before irradiation. The measurements after irradiations by high intensity pion beam with an integrated flux of 1.0*10/sup 14/ pions/cm/sup 2/ are also presented in this paper. (10 refs).

  10. Architecture of a fully integrated communication infrastructure for the smart home; Architektur einer vollintegrierten Kommunikationsinfrastruktur fuer das Smart Home

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Falk-Moritz; Kays, Ruediger [TU Dortmund (Germany). Lehrstuhl fuer Kommunikationstechnik

    2012-07-01

    For some time, applications in the areas of home automation, ambient assisted living and e-health are discussed. These require reliable and energy-efficient communication solutions in the home environment. In addition, new concepts that go hand in hand with the concept of the smart grids need an access to devices within the home environment. In the realization of smart homes the diversity of market participants involved, the parallel existing business models, the application requirements and the available communication systems make special demands on the underlying network infrastructure. Different solutions should be able to communicate with each other and compatible. In addition, the user expects a simple operation and configuration as well as a long-term support of the products. In the best case, the user is confronted with a single, integrated network infrastructure. Instead of separate systems for reading out of smart meters for monitoring the solar system, for health monitoring and the settings of multimedia devices, the telephone system, or computer network, a fully integrated smart home communications infrastructure should come into operation. This smart home infrastructure should be free of unnecessary duplication of structures; all equipment should be taken into account with a communication interface. The authors of the contribution under consideration report on a possible architecture of such a network infrastructure. Different grades are identified. A protocol stack for different technologies and the linking of different network hierarchies are described.

  11. Deep Space Atomic Clock

    Data.gov (United States)

    National Aeronautics and Space Administration — The Deep Space Atomic Clock (DSAC) project will develop a small, low mass atomic clock based on mercury-ion trap technology and demonstrate it in space providing the...

  12. Clocks and their discovery

    OpenAIRE

    Dugan, David

    2004-01-01

    Does technology, or the need for technology in the culture come first? Simon Schaffer in St Alban’s Abbey reflects on the connection between Christianity and clocks. God as the omniscient clock-maker.

  13. A Low-jitter 2.5-to-10 GHz Clock Multiplier Unit in CMOS

    NARCIS (Netherlands)

    van de Beek, R.C.H.; Vaucher, C.S.; Leenaerts, D.M.W.; Klumperink, Eric A.M.; Nauta, Bram

    2003-01-01

    Abstract— This paper demonstrates a low-jitter clock multiplier unit [1] that generates a 10 GHz output clock from a 2.5 GHz reference clock. An integrated 10 GHz LCoscillator is locked to the input clock, using a simple and fast phase detector circuit. This phase detector overcomes the speed

  14. Clock Tree Power Analysis

    OpenAIRE

    Austbø, Knut

    2016-01-01

    The buffered clock tree structure is commonly used to distribute the clock signal to the memory elements in digital circuits. Since the clock signal is used as a temporal reference, it has to be distributed to the registers with decent timing characteristics and low skew. In order to achieve this, buffers and inverters are inserted in the clock tree, typically by a synthesis tool. The clock tree is a major contributor to the power consumption. This is a result of a combination of high swit...

  15. Gastric Cancer (Biomarkers Knowledgebase (GCBKB: A Curated and Fully Integrated Knowledgebase of Putative Biomarkers Related to Gastric Cancer

    Directory of Open Access Journals (Sweden)

    Bernett T.K. Lee

    2006-01-01

    Full Text Available The Gastric Cancer (Biomarkers Knowledgebase (GCBKB (http://biomarkers.bii.a-star.edu.sg/background/gastricCancerBiomarkersKb.php is a curated and fully integrated knowledgebase that provides data relating to putative biomarkers that may be used in the diagnosis and prognosis of gastric cancer. It is freely available to all users. The data contained in the knowledgebase was derived from a large literature source and the putative biomarkers therein have been annotated with data from the public domain. The knowledgebase is maintained by a curation team who update the data from a defined source. As well as mining data from the literature, the knowledgebase will also be populated with unpublished experimental data from investigators working in the gastric cancer biomarker discovery field. Users can perform searches to identify potential markers defined by experiment type, tissue type and disease state. Search results may be saved, manipulated and retrieved at a later date. As far as the authors are aware this is the first open access database dedicated to the discovery and investigation of gastric cancer biomarkers.

  16. Fully integrated high quality factor GmC bandpass filter stage with highly linear operational transconductance amplifier

    Science.gov (United States)

    Briem, Jochen; Mader, Marco; Reiter, Daniel; Amirpour, Raul; Grözing, Markus; Berroth, Manfred

    2017-09-01

    This paper presents an electrical, fully integrated, high quality (Q) factor GmC bandpass filter (BPF) stage for a wireless 27 MHz direct conversion receiver for a bendable sensor system-in-foil (Briem et al., 2016). The core of the BPF with a Q factor of more than 200 is an operational transconductance amplifier (OTA) with a high linearity at an input range of up to 300 mVpp, diff. The OTA's signal-to-noise-and-distortion-ratio (SNDR) of more than 80 dB in the mentioned range is achieved by stabilizing its transconductance Gm with a respective feedback loop and a source degeneration resistors RDG. The filter stage can be tuned and is tolerant to global and local process variations due to offset and common-mode feedback (CMFB) control circuits. The results are determined by periodic steady state (PSS) simulations at more than 200 global and local process variation parameter and temperature points and corner simulations. It is expected, that the parasitic elements of the layout have no significant influence on the filter behaviour. The current consumption of the whole filter stage is less than 600 µA.

  17. Pb(Zr,TiO3 (PZT Thin Film Sensors for Fully-Integrated, Passive Telemetric Transponders

    Directory of Open Access Journals (Sweden)

    Richard X. FU

    2011-04-01

    Full Text Available The great potential of taking advantages of PZT in a single chip to achieve inexpensive, fully-integrated, passive telemetric transponders has been shown in this paper. The processes for the sputter deposition of Pb(Zr,TiO3 (PZT thin films from two different composite targets on both Si and c-plane sapphire substrates have been demonstrated. PZT thin films have been deposited by sputter technique. PZT films were deposited onto substrates (Si [(100 Cz wafer] and c-plane sapphire (0001//Ti//Pt followed by sputter-deposited Pt top electrodes. X-ray diffraction results showed that both sputtered PZT films were textured along the [110] direction. The degree of preference for the [110] direction was greater on sapphire substrate where the intensity of that peak is seen to be larger compared to the intensity one Si substrate. TEM data revealed that both sputtered PZT films were polycrystalline in nature. Selected area diffraction (SAD pattern showed that the degree of disorientation between the crystallites was smaller on sapphire substrate compared to on Si substrate, which confirmed the results from the XRD. The remnant polarization Pr on sapphire substrate was larger than on Si’s. The leakage current for the 11 % Pb target sputtered film was much less than 22 % Pb target sputtered film. The breakdown voltage on sapphire substrate was the best. However, for the 11 % Pb target sputtered film’s breakdown voltage was much higher than 22 % Pb target sputtered film.

  18. A Closed-Loop Proportional-Integral (PI) Control Software for Fully Mechanically Controlled Automated Electron Microscopic Tomography

    Energy Technology Data Exchange (ETDEWEB)

    2016-06-23

    A closed-loop proportional-integral (PI) control software is provided for fully mechanically controlled automated electron microscopic tomography. The software is developed based on Gatan DigitalMicrograph, and is compatible with Zeiss LIBRA 120 transmission electron microscope. However, it can be expanded to other TEM instrument with modification. The software consists of a graphical user interface, a digital PI controller, an image analyzing unit, and other drive units (i.e.: image acquire unit and goniometer drive unit). During a tomography data collection process, the image analyzing unit analyzes both the accumulated shift and defocus value of the latest acquired image, and provides the results to the digital PI controller. The digital PI control compares the results with the preset values and determines the optimum adjustments of the goniometer. The goniometer drive unit adjusts the spatial position of the specimen according to the instructions given by the digital PI controller for the next tilt angle and image acquisition. The goniometer drive unit achieves high precision positioning by using a backlash elimination method. The major benefits of the software are: 1) the goniometer drive unit keeps pre-aligned/optimized beam conditions unchanged and achieves position tracking solely through mechanical control; 2) the image analyzing unit relies on only historical data and therefore does not require additional images/exposures; 3) the PI controller enables the system to dynamically track the imaging target with extremely low system error.

  19. Modeling, simulation, and fabrication of a fully integrated, acid-stable, scalable solar-driven water-splitting system.

    Science.gov (United States)

    Walczak, Karl; Chen, Yikai; Karp, Christoph; Beeman, Jeffrey W; Shaner, Matthew; Spurgeon, Joshua; Sharp, Ian D; Amashukeli, Xenia; West, William; Jin, Jian; Lewis, Nathan S; Xiang, Chengxiang

    2015-02-01

    A fully integrated solar-driven water-splitting system comprised of WO3 /FTO/p(+) n Si as the photoanode, Pt/TiO2 /Ti/n(+) p Si as the photocathode, and Nafion as the membrane separator, was simulated, assembled, operated in 1.0 M HClO4 , and evaluated for performance and safety characteristics under dual side illumination. A multi-physics model that accounted for the performance of the photoabsorbers and electrocatalysts, ion transport in the solution electrolyte, and gaseous product crossover was first used to define the optimal geometric design space for the system. The photoelectrodes and the membrane separators were then interconnected in a louvered design system configuration, for which the light-absorbing area and the solution-transport pathways were simultaneously optimized. The performance of the photocathode and the photoanode were separately evaluated in a traditional three-electrode photoelectrochemical cell configuration. The photocathode and photoanode were then assembled back-to-back in a tandem configuration to provide sufficient photovoltage to sustain solar-driven unassisted water-splitting. The current-voltage characteristics of the photoelectrodes showed that the low photocurrent density of the photoanode limited the overall solar-to-hydrogen (STH) conversion efficiency due to the large band gap of WO3 . A hydrogen-production rate of 0.17 mL hr(-1) and a STH conversion efficiency of 0.24 % was observed in a full cell configuration for >20 h with minimal product crossover in the fully operational, intrinsically safe, solar-driven water-splitting system. The solar-to-hydrogen conversion efficiency, ηSTH , calculated using the multiphysics numerical simulation was in excellent agreement with the experimental behavior of the system. The value of ηSTH was entirely limited by the performance of the photoelectrochemical assemblies employed in this study. The louvered design provides a robust platform for implementation of various types of

  20. Fully integrated free-running InGaAs/InP single-photon detector for accurate lidar applications.

    Science.gov (United States)

    Yu, Chao; Shangguan, Mingjia; Xia, Haiyun; Zhang, Jun; Dou, Xiankang; Pan, Jian-Wei

    2017-06-26

    We present a fully integrated InGaAs/InP negative feedback avalanche diode (NFAD) based free-running single-photon detector (SPD) designed for accurate lidar applications. A free-piston Stirling cooler is used to cool down the NFAD with a large temperature range, and an active hold-off circuit implemented in a field programmable gate array is applied to further suppress the afterpulsing contribution. The key parameters of the free-running SPD including photon detection efficiency (PDE), dark count rate (DCR), afterpulse probability, and maximum count rate (MCR) are dedicatedly optimized for lidar application in practice. We then perform a field experiment using a Mie lidar system with 20 kHz pulse repetition frequency to compare the performance between the free-running InGaAs/InP SPD and a commercial superconducting nanowire single-photon detector (SNSPD). Our detector exhibits good performance with 1.6 Mcps MCR (0.6 μs hold-off time), 10% PDE, 950 cps DCR, and 18% afterpulse probability over 50 μs period. Such performance is worse than the SNSPD with 60% PDE and 300 cps DCR. However, after performing a specific algorithm that we have developed for afterpulse and count rate corrections, the lidar system performance in terms of range-corrected signal (Pr 2 ) distribution using our SPD agrees very well with the result using the SNSPD, with only a relative error of ∼2%. Due to the advantages of low-cost and small size of InGaAs/InP NFADs, such detector provides a practical solution for accurate lidar applications.

  1. GPS Composite Clock Analysis

    OpenAIRE

    Wright, James R.

    2008-01-01

    The GPS composite clock defines GPS time, the timescale used today in GPS operations. GPS time is illuminated by examination of its role in the complete estimation and control problem relative to UTC/TAI. The phase of each GPS clock is unobservable from GPS pseudorange measurements, and the mean phase of the GPS clock ensemble (GPS time) is unobservable. A new and useful observability definition is presented, together with new observability theorems, to demonstrate explicitly that GPS time is...

  2. Precision Clock Evaluation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Tests and evaluates high-precision atomic clocks for spacecraft, ground, and mobile applications. Supports performance evaluation, environmental testing,...

  3. Assimilation of SMOS-derived soil moisture in a fully integrated hydrological and soil-vegetation-atmosphere transfer model in Western Denmark

    DEFF Research Database (Denmark)

    Ridler, Marc-Etienne Francois; Madsen, Henrik; Stisen, Simon

    2014-01-01

    Real surface soil moisture retrieved from the Soil Moisture and Ocean Salinity (SMOS) satellite is downscaled and assimilated in a fully integrated hydrological and soil-vegetation-atmosphere transfer (MIKE SHE SW-ET) model using a bias aware ensemble transform Kalman filter (Bias-ETKF). Satellite...

  4. Round-the-clock power supply and a sustainable economy via synergistic integration of solar thermal power and hydrogen processes.

    Science.gov (United States)

    Gençer, Emre; Mallapragada, Dharik S; Maréchal, François; Tawarmalani, Mohit; Agrawal, Rakesh

    2015-12-29

    We introduce a paradigm-"hydricity"-that involves the coproduction of hydrogen and electricity from solar thermal energy and their judicious use to enable a sustainable economy. We identify and implement synergistic integrations while improving each of the two individual processes. When the proposed integrated process is operated in a standalone, solely power production mode, the resulting solar water power cycle can generate electricity with unprecedented efficiencies of 40-46%. Similarly, in standalone hydrogen mode, pressurized hydrogen is produced at efficiencies approaching ∼50%. In the coproduction mode, the coproduced hydrogen is stored for uninterrupted solar power production. When sunlight is unavailable, we envision that the stored hydrogen is used in a "turbine"-based hydrogen water power (H2WP) cycle with the calculated hydrogen-to-electricity efficiency of 65-70%, which is comparable to the fuel cell efficiencies. The H2WP cycle uses much of the same equipment as the solar water power cycle, reducing capital outlays. The overall sun-to-electricity efficiency of the hydricity process, averaged over a 24-h cycle, is shown to approach ∼35%, which is nearly the efficiency attained by using the best multijunction photovoltaic cells along with batteries. In comparison, our proposed process has the following advantages: (i) It stores energy thermochemically with a two- to threefold higher density, (ii) coproduced hydrogen has alternate uses in transportation/chemical/petrochemical industries, and (iii) unlike batteries, the stored energy does not discharge over time and the storage medium does not degrade with repeated uses.

  5. Potential impacts of human water management on the European heat wave 2003 using fully integrated bedrock-to-atmosphere simulations

    Science.gov (United States)

    Keune, Jessica; Sulis, Mauro; Kollet, Stefan; Wada, Yoshihide

    2017-04-01

    Recent studies indicate that anthropogenic impacts on the terrestrial water cycle lead to a redistribution of water resources in space and time, can trigger land-atmosphere feedbacks, such as the soil moisture-precipitation feedback, and potentially enhance convection and precipitation. Yet, these studies do not consider the full hydrologic cycle from the bedrock to the atmosphere or apply simplified hydrologic models, neglecting the connection of irrigation to water withdrawal and groundwater depletion. Thus, there is a need to incorporate water resource management in 3D hydrologic models coupled to earth system models. This study addresses the impact of water resource management, i.e. irrigation and groundwater abstraction, on land-atmosphere feedbacks through the terrestrial hydrologic cycle in a physics-based soil-vegetation-atmosphere system simulating 3D groundwater dynamics at the continental scale. The integrated Terrestrial Systems Modeling Platform, TerrSysMP, consisting of the three-dimensional subsurface and overland flow model ParFlow, the Community Land Model CLM3.5 and the numerical weather prediction model COSMO of the German Weather Service, is set up over the European CORDEX domain in 0.11° resolution. The model closes the terrestrial water and energy cycles from aquifers into the atmosphere. Anthropogenic impacts are considered by applying actual daily estimates of irrigation and groundwater abstraction from Wada et al. (2012, 2016), as a source at the land surface and explicit removal of groundwater from aquifer storage, respectively. Simulations of the fully coupled system are performed over the 2003 European heat wave and compared to a reference simulation, which does not consider human interactions in the terrestrial water cycle. We study the space and time characteristics and evolution of temperature extremes, and soil moisture and precipitation anomalies influenced by human water management during the heat wave. A first set of simulations

  6. Biological Clocks & Circadian Rhythms

    Science.gov (United States)

    Robertson, Laura; Jones, M. Gail

    2009-01-01

    The study of biological clocks and circadian rhythms is an excellent way to address the inquiry strand in the National Science Education Standards (NSES) (NRC 1996). Students can study these everyday phenomena by designing experiments, gathering and analyzing data, and generating new experiments. As students explore biological clocks and circadian…

  7. 50 ch x 250 Gbit/s 32-QAM Transmission over a Fully Integrated 7-core Multicore Link

    DEFF Research Database (Denmark)

    Castro, C.; Jain, S.; Jung, Y.

    2017-01-01

    A transmitted distance of 180 km over an integrated multicore link is demonstrated for a C-band 32-QAM WDM system, where the complete usable amplification region of the integrated 7-coreamplifiers, supporting 50 channels per core, is exploited....

  8. The Deep Space Atomic Clock Mission

    Science.gov (United States)

    Ely, Todd A.; Koch, Timothy; Kuang, Da; Lee, Karen; Murphy, David; Prestage, John; Tjoelker, Robert; Seubert, Jill

    2012-01-01

    The Deep Space Atomic Clock (DSAC) mission will demonstrate the space flight performance of a small, low-mass, high-stability mercury-ion atomic clock with long term stability and accuracy on par with that of the Deep Space Network. The timing stability introduced by DSAC allows for a 1-Way radiometric tracking paradigm for deep space navigation, with benefits including increased tracking via utilization of the DSN's Multiple Spacecraft Per Aperture (MSPA) capability and full ground station-spacecraft view periods, more accurate radio occultation signals, decreased single-frequency measurement noise, and the possibility for fully autonomous on-board navigation. Specific examples of navigation and radio science benefits to deep space missions are highlighted through simulations of Mars orbiter and Europa flyby missions. Additionally, this paper provides an overview of the mercury-ion trap technology behind DSAC, details of and options for the upcoming 2015/2016 space demonstration, and expected on-orbit clock performance.

  9. Photoperiodic plasticity in circadian clock neurons in insects

    Directory of Open Access Journals (Sweden)

    Sakiko eShiga

    2013-08-01

    Full Text Available Since Bünning’s observation of circadian rhythms and photoperiodism in the runner bean Phaseolus multiflorus in 1936, many studies have shown that photoperiodism is based on the circadian clock system. In insects, involvement of circadian clock genes or neurons has been recently shown in the photoperiodic control of developmental arrests, diapause. Based on molecular and neuronal studies in Drosophila melanogaster, photoperiodic changes have been reported for expression patterns of the circadian clock genes, subcellular distribution of clock proteins, fiber distribution, or the number of plausible clock neurons in different species. Photoperiod sets peaks of per or tim mRNA abundance at lights-off in Sarcophaga crassipalpis, Chymomyza costata and Protophormia terraenovae. Abundance of per and Clock mRNA changes by photoperiod in Pyrrhocoris apterus. Subcellular Per distribution in circadian clock neurons changes with photoperiod in P. terraenovae. Although photoperiodism is not known in Leucophaea maderae, under longer day length, more stomata and longer commissural fibers of circadian clock neurons have been found. These plastic changes in the circadian clock neurons could be an important constituent for photoperiodic clock mechanisms to integrate repetitive photoperiodic information and produce different outputs based on day length.

  10. 200 Gbit/s 16QAM WDM transmission over a fully integrated cladding pumped 7-Core MCF System

    DEFF Research Database (Denmark)

    Castro, C.; Jain, S.; Jung, Y.

    2017-01-01

    A complete, realistic integrated system is investigated, consisting of directly spliced 7-core MCF, cladding-pumped 7-core amplifiers, isolators, and couplers. The system is demonstrated in a 16QAM C-band WDM scenario over 720 km....

  11. An Integrated Photogrammetric and Spatial Database Management System for Producing Fully Structured Data Using Aerial and Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Farshid Farnood Ahmadi

    2009-03-01

    Full Text Available 3D spatial data acquired from aerial and remote sensing images by photogrammetric techniques is one of the most accurate and economic data sources for GIS, map production, and spatial data updating. However, there are still many problems concerning storage, structuring and appropriate management of spatial data obtained using these techniques. According to the capabilities of spatial database management systems (SDBMSs; direct integration of photogrammetric and spatial database management systems can save time and cost of producing and updating digital maps. This integration is accomplished by replacing digital maps with a single spatial database. Applying spatial databases overcomes the problem of managing spatial and attributes data in a coupled approach. This management approach is one of the main problems in GISs for using map products of photogrammetric workstations. Also by the means of these integrated systems, providing structured spatial data, based on OGC (Open GIS Consortium standards and topological relations between different feature classes, is possible at the time of feature digitizing process. In this paper, the integration of photogrammetric systems and SDBMSs is evaluated. Then, different levels of integration are described. Finally design, implementation and test of a software package called Integrated Photogrammetric and Oracle Spatial Systems (IPOSS is presented.

  12. A fully integrated continuous-time 1Hz low-pass filter with high dynamic range and low distortion

    DEFF Research Database (Denmark)

    Shah, Peter Jivan

    1993-01-01

    A first order 1Hz integrated filter needing no external components is described. It uses an on-chip capacitor of 100pF and a new differential transconductance amplifier which allows direct implementation of very small transconductances by using MOS transistors in their triode region. This further......A first order 1Hz integrated filter needing no external components is described. It uses an on-chip capacitor of 100pF and a new differential transconductance amplifier which allows direct implementation of very small transconductances by using MOS transistors in their triode region...

  13. A low jitter PLL clock used for phase change memory

    Science.gov (United States)

    Xiao, Hong; Houpeng, Chen; Zhitang, Song; Daolin, Cai; Xi, Li

    2013-02-01

    A fully integrated low-jitter, precise frequency CMOS phase-locked loop (PLL) clock for the phase change memory (PCM) drive circuit is presented. The design consists of a dynamic dual-reset phase frequency detector (PFD) with high frequency acquisition, a novel low jitter charge pump, a CMOS ring oscillator based voltage-controlled oscillator (VCO), a 2nd order passive loop filter, and a digital frequency divider. The design is fabricated in 0.35 μm CMOS technology and consumes 20 mW from a supply voltage of 5 V. In terms of the PCM's program operation requirement, the output frequency range is from 1 to 140 MHz. For the 140 MHz output frequency, the circuit features a cycle-to-cycle jitter of 28 ps RMS and 250 ps peak-to-peak.

  14. Towards a fully automated lab-on-a-disc system integrating sample enrichment and detection of analytes from complex matrices

    DEFF Research Database (Denmark)

    Andreasen, Sune Zoëga

    Lab-on-a-chip systems (LoC) has been actively researched and developed for at least the last 25 years, yet integration of an efficient and robust sample pretreatment method still proves to be a challenge in the field. This lack of sample pre-treatment methods in LoC platforms prevents the technol...

  15. Calcium and SOL Protease Mediate Temperature Resetting of Circadian Clocks

    Science.gov (United States)

    Tataroglu, Ozgur; Zhao, Xiaohu; Busza, Ania; Ling, Jinli; O’Neill, John S.; Emery, Patrick

    2015-01-01

    Summary Circadian clocks integrate light and temperature input to remain synchronized with the day/night cycle. Although light input to the clock is well studied, the molecular mechanisms by which circadian clocks respond to temperature remain poorly understood. We found that temperature phase shifts Drosophila circadian clocks through degradation of the pacemaker protein TIM. This degradation is mechanistically distinct from photic CRY-dependent TIM degradation. Thermal TIM degradation is triggered by cytosolic calcium increase and CALMODULIN binding to TIM and is mediated by the atypical calpain protease SOL. This thermal input pathway and CRY-dependent light input thus converge on TIM, providing a molecular mechanism for the integration of circadian light and temperature inputs. Mammals use body temperature cycles to keep peripheral clocks synchronized with their brain pacemaker. Interestingly, downregulating the mammalian SOL homolog SOLH blocks thermal mPER2 degradation and phase shifts. Thus, we propose that circadian thermosensation in insects and mammals share common principles. PMID:26590423

  16. Crosstalk between the circadian clock and innate immunity in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Chong Zhang

    Full Text Available The circadian clock integrates temporal information with environmental cues in regulating plant development and physiology. Recently, the circadian clock has been shown to affect plant responses to biotic cues. To further examine this role of the circadian clock, we tested disease resistance in mutants disrupted in CCA1 and LHY, which act synergistically to regulate clock activity. We found that cca1 and lhy mutants also synergistically affect basal and resistance gene-mediated defense against Pseudomonas syringae and Hyaloperonospora arabidopsidis. Disrupting the circadian clock caused by overexpression of CCA1 or LHY also resulted in severe susceptibility to P. syringae. We identified a downstream target of CCA1 and LHY, GRP7, a key constituent of a slave oscillator regulated by the circadian clock and previously shown to influence plant defense and stomatal activity. We show that the defense role of CCA1 and LHY against P. syringae is at least partially through circadian control of stomatal aperture but is independent of defense mediated by salicylic acid. Furthermore, we found defense activation by P. syringae infection and treatment with the elicitor flg22 can feedback-regulate clock activity. Together this data strongly supports a direct role of the circadian clock in defense control and reveal for the first time crosstalk between the circadian clock and plant innate immunity.

  17. Design, fabrication, and characterisation of fully etched TM grating coupler for photonic integrated system-in-package

    Science.gov (United States)

    Gili-de-Villasante, Oriol; Tcheg, Paul; Wang, Bei; Suna, Alpaslan; Giannoulis, Giannis; Lazarou, Ioannis; Apostolopoulos, Dimitrios; Avramopoulos, Hercules; Pleros, Nikos; Baus, Matthias; Karl, Matthias; Tekin, Tolga

    2012-06-01

    Grating couplers are the best solution for testing nano-photonic circuits. Their main benefit is that they allow access via an optical fiber from the top and therefore there is no need to dice the chip and prepare the facets crucially. In the PLATON project grating couplers were designed to couple TM mode into and out of the SOI waveguides. Simulations came up with a grating coupler layout capable of theoretical coupling losses lower than 3dB for 1550 nm in TM configuration. A fully etched grating structure was chosen for fabrication simplicity and the optimal filling factor was found. The structures were fabricated using proximity error correction (PEC) and show a uniform coupling efficiency for all couplers. Therefore they are well-suited for all applications which demand for stable fiber-to-chip coupling. The spectral response of the structures was measured from 1500 to 1580 nm with 2 nm step and measuring the fiber-tofiber losses of three straight waveguides equipped with three grating couplers with different gap widths. The optimal grating period exhibits adequate coupling losses of 3.23 dB per coupler at 1557 nm, being therefore the most promising design.

  18. SRC: Smart Reminder Clock

    Science.gov (United States)

    Kasim, Shahreen; Hafit, Hanayanti; Leong, Tan Hua; Hashim, Rathiah; Ruslai, Husni; Jahidin, Kamaruzzaman; Syafwan Arshad, Mohammad

    2016-11-01

    Nowadays, some people facing the problem to wake up in the morning. This was result to absence of the classes, meetings, and even exams. The aim of this project is to develop an android application that can force the user to wake up. The method used in this application are pedometer and Short Message Service (SMS) function. This application need the user to take their smartphone and walk about 10 steps to disable it, when the alarm clock is activated. After that, when the alarm clock was rang, this alarm application has automatically send a message to the users’ friends or parents phone to wake them up.

  19. Smith-Magenis syndrome results in disruption of CLOCK gene transcription and reveals an integral role for RAI1 in the maintenance of circadian rhythmicity.

    Science.gov (United States)

    Williams, Stephen R; Zies, Deborah; Mullegama, Sureni V; Grotewiel, Michael S; Elsea, Sarah H

    2012-06-08

    Haploinsufficiency of RAI1 results in Smith-Magenis syndrome (SMS), a disorder characterized by intellectual disability, multiple congenital anomalies, obesity, neurobehavioral abnormalities, and a disrupted circadian sleep-wake pattern. An inverted melatonin rhythm (i.e., melatonin peaks during the day instead of at night) and associated sleep-phase disturbances in individuals with SMS, as well as a short-period circadian rhythm in mice with a chromosomal deletion of Rai1, support SMS as a circadian-rhythm-dysfunction disorder. However, the molecular cause of the circadian defect in SMS has not been described. The circadian oscillator temporally orchestrates metabolism, physiology, and behavior largely through transcriptional modulation. Data support RAI1 as a transcriptional regulator, but the genes it might regulate are largely unknown. Investigation into the role that RAI1 plays in the regulation of gene transcription and circadian maintenance revealed that RAI1 regulates the transcription of circadian locomotor output cycles kaput (CLOCK), a key component of the mammalian circadian oscillator that transcriptionally regulates many critical circadian genes. Data further show that haploinsufficiency of RAI1 and Rai1 in SMS fibroblasts and the mouse hypothalamus, respectively, results in the transcriptional dysregulation of the circadian clock and causes altered expression and regulation of multiple circadian genes, including PER2, PER3, CRY1, BMAL1, and others. These data suggest that heterozygous mutation of RAI1 and Rai1 leads to a disrupted circadian rhythm and thus results in an abnormal sleep-wake cycle, which can contribute to an abnormal feeding pattern and dependent cognitive performance. Finally, we conclude that RAI1 is a positive transcriptional regulator of CLOCK, pinpointing a novel and important role for this gene in the circadian oscillator. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  20. Goober: A fully integrated and user-friendly microarray data management and analysis solution for core labs and bench biologists

    Directory of Open Access Journals (Sweden)

    Luo Wen

    2009-03-01

    Full Text Available Despite the large number of software tools developed to address different areas of microarray data analysis, very few offer an all-in-one solution with little learning curve. For microarray core labs, there are even fewer software packages available to help with their routine but critical tasks, such as data quality control (QC and inventory management. We have developed a simple-to-use web portal to allow bench biologists to analyze and query complicated microarray data and related biological pathways without prior training. Both experiment-based and gene-based analysis can be easily performed, even for the first-time user, through the intuitive multi-layer design and interactive graphic links. While being friendly to inexperienced users, most parameters in Goober can be easily adjusted via drop-down menus to allow advanced users to tailor their needs and perform more complicated analysis. Moreover, we have integrated graphic pathway analysis into the website to help users examine microarray data within the relevant biological content. Goober also contains features that cover most of the common tasks in microarray core labs, such as real time array QC, data loading, array usage and inventory tracking. Overall, Goober is a complete microarray solution to help biologists instantly discover valuable information from a microarray experiment and enhance the quality and productivity of microarray core labs. The whole package is freely available at http://sourceforge.net/projects/goober. A demo web server is available at http://www.goober-array.org.

  1. A fully integrated sensor SoC with digital calibration hardware and wireless transceiver at 2.4 GHz.

    Science.gov (United States)

    Kim, Dong-Sun; Jang, Sung-Joon; Hwang, Tae-Ho

    2013-05-21

    A single-chip sensor system-on-a-chip (SoC) that implements radio for 2.4 GHz, complete digital baseband physical layer (PHY), 10-bit sigma-delta analog-to-digital converter and dedicated sensor calibration hardware for industrial sensing systems has been proposed and integrated in a 0.18-μm CMOS technology. The transceiver's building block includes a low-noise amplifier, mixer, channel filter, receiver signal-strength indicator, frequency synthesizer, voltage-controlled oscillator, and power amplifier. In addition, the digital building block consists of offset quadrature phase-shift keying (OQPSK) modulation, demodulation, carrier frequency offset compensation, auto-gain control, digital MAC function, sensor calibration hardware and embedded 8-bit microcontroller. The digital MAC function supports cyclic redundancy check (CRC), inter-symbol timing check, MAC frame control, and automatic retransmission. The embedded sensor signal processing block consists of calibration coefficient calculator, sensing data calibration mapper and sigma-delta analog-to-digital converter with digital decimation filter. The sensitivity of the overall receiver and the error vector magnitude (EVM) of the overall transmitter are -99 dBm and 18.14%, respectively. The proposed calibration scheme has a reduction of errors by about 45.4% compared with the improved progressive polynomial calibration (PPC) method and the maximum current consumption of the SoC is 16 mA.

  2. A Fully Integrated Sensor SoC with Digital Calibration Hardware and Wireless Transceiver at 2.4 GHz

    Directory of Open Access Journals (Sweden)

    Dong-Sun Kim

    2013-05-01

    Full Text Available A single-chip sensor system-on-a-chip (SoC that implements radio for 2.4 GHz, complete digital baseband physical layer (PHY, 10-bit sigma-delta analog-to-digital converter and dedicated sensor calibration hardware for industrial sensing systems has been proposed and integrated in a 0.18-μm CMOS technology. The transceiver’s building block includes a low-noise amplifier, mixer, channel filter, receiver signal-strength indicator, frequency synthesizer, voltage-controlled oscillator, and power amplifier. In addition, the digital building block consists of offset quadrature phase-shift keying (OQPSK modulation, demodulation, carrier frequency offset compensation, auto-gain control, digital MAC function, sensor calibration hardware and embedded 8-bit microcontroller. The digital MAC function supports cyclic redundancy check (CRC, inter-symbol timing check, MAC frame control, and automatic retransmission. The embedded sensor signal processing block consists of calibration coefficient calculator, sensing data calibration mapper and sigma-delta analog-to-digital converter with digital decimation filter. The sensitivity of the overall receiver and the error vector magnitude (EVM of the overall transmitter are −99 dBm and 18.14%, respectively. The proposed calibration scheme has a reduction of errors by about 45.4% compared with the improved progressive polynomial calibration (PPC method and the maximum current consumption of the SoC is 16 mA.

  3. Novel strategy for sulfapyridine detection using a fully integrated electrochemical Bio-MEMS: Application to honey analysis.

    Science.gov (United States)

    Hassani, Nadia El Alami El; Baraket, Abdoullatif; Neto, Ernandes Taveira Tenório; Lee, Michael; Salvador, J-Pablo; Marco, M-Pilar; Bausells, Joan; Bari, Nezha El; Bouchikhi, Benachir; Elaissari, Abdelhamid; Errachid, Abdelhamid; Zine, Nadia

    2017-07-15

    Sulfapyridine (SPy) is a sulfonamide antibiotic largely employed as veterinary drugs for prophylactic and therapeutic purposes. Therefore, its spread in the food products has to be restricted. Herein, we report the synthesis and characterization of a novel electrochemical biosensor based on gold microelectrodes modified with a new structure of magnetic nanoparticles (MNPs) coated with poly(pyrrole-co-pyrrole-2-carboxylic acid) (Py/Py-COOH) for high efficient detection of SPy. This analyte was quantified through a competitive detection procedure with 5-[4-(amino)phenylsulfonamide]-5-oxopentanoic acid-BSA (SA2-BSA) antigens toward polyclonal antibody (Ab-155). Initially, gold working electrodes (WEs) of integrated biomicro electro-mechanical system (BioMEMS) were functionalized by Ppy-COOH/MNPs, using a chronoamperometric (CA) electrodeposition. Afterward, SA2-BSA was covalently bonded to Py/Py-COOH/MNP modified gold WEs through amide bonding. The competitive detection of the analyte was made by a mixture of a fixed concentration of Ab-155 and decreasing concentrations of SPy from 50µgL -1 to 2ngL -1 . Atomic Force Microscopy characterization was performed in order to ensure Ppy-COOH/MNPs electrodeposition on the microelectrode surfaces. Electrochemical measurements of SPy detection were carried out using electrochemical impedance spectroscopy (EIS). This biosensor was found to be highly sensitive and specific for SPy, with a limit of detection of 0.4ngL -1 . This technique was exploited to detect SPy in honey samples by using the standard addition method. The measurements were highly reproducible for detection and interferences namely, sulfadiazine (SDz), sulfathiazole (STz) and sulfamerazine (SMz). Taking these advantages of sensitivity, specificity, and low cost, our system provides a new horizon for development of advanced immunoassays in industrial food control. Copyright © 2016. Published by Elsevier B.V.

  4. Ultracold Molecules in Optical Lattices: Efficient Production and Application to Molecular Clocks

    Science.gov (United States)

    2015-05-03

    Martin, M. M. Boyd, and J. Ye. Rabi spectroscopy and excitation inhomogeneity in a one-dimensional optical lattice clock. Phys. Rev. A, 80:052703, 2009...can fully control the molecules’ internal and external quantum states, as in state-of-the-art atomic lattice clocks. Using the quantized molecular...spectra in an optical lattice , we devised a new lattice thermometry method that is advantageous for many lattice experiments, including clocks and

  5. Clock Reaction: Outreach Attraction

    Science.gov (United States)

    Carpenter, Yuen-ying; Phillips, Heather A.; Jakubinek, Michael B.

    2010-01-01

    Chemistry students are often introduced to the concept of reaction rates through demonstrations or laboratory activities involving the well-known iodine clock reaction. For example, a laboratory experiment involving thiosulfate as an iodine scavenger is part of the first-year general chemistry laboratory curriculum at Dalhousie University. With…

  6. Cryptochromes and Biological Clocks

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 9. Cryptochromes and Biological Clocks. V R Bhagwat. General Article Volume 7 Issue 9 September 2002 pp 36-48. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/09/0036-0048. Keywords.

  7. Decamp Clock Board Firmware

    International Nuclear Information System (INIS)

    Vicente, J. de; Castilla, J.; Martinez, G.

    2007-01-01

    Decamp (Dark Energy Survey Camera) is a new instrument designed to explore the universe aiming to reveal the nature of Dark Energy. The camera consists of 72 CCDs and 520 Mpixels. The readout electronics of DECam is based on the Monsoon system. Monsoon is a new image acquisition system developed by the NOAO (National Optical Astronomical Observatory) for the new generation of astronomical cameras. The Monsoon system uses three types of boards inserted in a Eurocard format based crate: master control board, acquisition board and clock board. The direct use of the Monsoon system for DECam readout electronics requires nine crates mainly due to the high number of clock boards needed. Unfortunately, the available space for DECam electronics is constrained to four crates at maximum. The major drawback to achieve such desired compaction degree resides in the clock board signal density. This document describes the changes performed at CIEMAT on the programmable logic of the Monsoon clock board aiming to meet such restricted space constraints. (Author) 5 refs

  8. Decamp Clock Board Firmware

    Energy Technology Data Exchange (ETDEWEB)

    Vicente, J. de; Castilla, J.; Martinez, G.

    2007-09-27

    Decamp (Dark Energy Survey Camera) is a new instrument designed to explore the universe aiming to reveal the nature of Dark Energy. The camera consists of 72 CCDs and 520 Mpixels. The readout electronics of DECam is based on the Monsoon system. Monsoon is a new image acquisition system developed by the NOAO (National Optical Astronomical Observatory) for the new generation of astronomical cameras. The Monsoon system uses three types of boards inserted in a Eurocard format based crate: master control board, acquisition board and clock board. The direct use of the Monsoon system for DECam readout electronics requires nine crates mainly due to the high number of clock boards needed. Unfortunately, the available space for DECam electronics is constrained to four crates at maximum. The major drawback to achieve such desired compaction degree resides in the clock board signal density. This document describes the changes performed at CIEMAT on the programmable logic of the Monsoon clock board aiming to meet such restricted space constraints. (Author) 5 refs.

  9. A fully integrated distance readout ELISA-Chip for point-of-care testing with sample-in-answer-out capability.

    Science.gov (United States)

    Liu, Dan; Li, Xingrui; Zhou, Junkai; Liu, Shibo; Tian, Tian; Song, Yanling; Zhu, Zhi; Zhou, Leiji; Ji, Tianhai; Yang, Chaoyong

    2017-10-15

    Enzyme-linked immunosorbent assay (ELISA) is a popular laboratory technique for detection of disease-specific protein biomarkers with high specificity and sensitivity. However, ELISA requires labor-intensive and time-consuming procedures with skilled operators and spectroscopic instrumentation. Simplification of the procedures and miniaturization of the devices are crucial for ELISA-based point-of-care (POC) testing in resource-limited settings. Here, we present a fully integrated, instrument-free, low-cost and portable POC platform which integrates the process of ELISA and the distance readout into a single microfluidic chip. Based on manipulation using a permanent magnet, the process is initiated by moving magnetic beads with capture antibody through different aqueous phases containing ELISA reagents to form bead/antibody/antigen/antibody sandwich structure, and finally converts the molecular recognition signal into a highly sensitive distance readout for visual quantitative bioanalysis. Without additional equipment and complicated operations, our integrated ELISA-Chip with distance readout allows ultrasensitive quantitation of disease biomarkers within 2h. The ELISA-Chip method also showed high specificity, good precision and great accuracy. Furthermore, the ELISA-Chip system is highly applicable as a sandwich-based platform for the detection of a variety of protein biomarkers. With the advantages of visual analysis, easy operation, high sensitivity, and low cost, the integrated sample-in-answer-out ELISA-Chip with distance readout shows great potential for quantitative POCT in resource-limited settings. Copyright © 2017. Published by Elsevier B.V.

  10. Comparative Analysis of Clinical-Scale IFN-γ-Positive T-Cell Enrichment Using Partially and Fully Integrated Platforms.

    Science.gov (United States)

    Priesner, Christoph; Esser, Ruth; Tischer, Sabine; Marburger, Michael; Aleksandrova, Krasimira; Maecker-Kolhoff, Britta; Heuft, Hans-Gert; Goudeva, Lilia; Blasczyk, Rainer; Arseniev, Lubomir; Köhl, Ulrike; Eiz-Vesper, Britta; Klöß, Stephan

    2016-01-01

    The infusion of enriched CMV-specific donor T-cells appears to be a suitable alternative for the treatment of drug-resistant CMV reactivation or de novo infection after both solid organ and hematopoietic stem cell transplantation. Antiviral lymphocytes can be selected from apheresis products using the CliniMACS Cytokine-Capture-System ® either with the well-established CliniMACS ® Plus (Plus) device or with its more versatile successor CliniMACS Prodigy ® (Prodigy). Manufacturing of CMV-specific T-cells was carried out with the Prodigy and Plus in parallel starting with 0.8-1 × 10 9 leukocytes collected by lymphapheresis ( n  = 3) and using the MACS GMP PepTivator ® HCMVpp65 for antigenic restimulation. Target and non-target cells were quantified by a newly developed single-platform assessment and gating strategy using positive (CD3/CD4/CD8/CD45/IFN-γ), negative (CD14/CD19/CD56), and dead cell (7-AAD) discriminators. Both devices produced largely similar results for target cell viabilities: 37.2-52.2% (Prodigy) vs. 51.1-62.1% (Plus) CD45 + /7-AAD - cells. Absolute numbers of isolated target cells were 0.1-3.8 × 10 6 viable IFN-γ + CD3 + T-cells. The corresponding proportions of IFN-γ + CD3 + T-cells ranged between 19.2 and 95.1% among total CD3 + T-cells and represented recoveries of 41.9-87.6%. Within two parallel processes, predominantly IFN-γ + CD3 + CD8 + cytotoxic T-cells were enriched compared to one process that yielded a higher amount of IFN-γ + CD3 + CD4 + helper T lymphocytes. T-cell purity was higher for the Prodigies products that displayed a lower content of contaminating IFN-γ - T-cells (3.6-20.8%) compared to the Plus products (19.9-80.0%). The manufacturing process on the Prodigy saved both process and hands-on time due to its higher process integration and ability for unattended operation. Although the usage of both instruments yielded comparable results, the lower content of residual IFN-γ - T-cells in the target fractions

  11. Comparative analysis of clinical-scale IFN-gamma positive T-cell enrichment using partially and fully integrated platforms

    Directory of Open Access Journals (Sweden)

    Christoph Priesner

    2016-09-01

    Full Text Available Background and aims. The infusion of enriched CMV-specific donor T-cells appears to be a suitable alternative for the treatment of drug resistant CMV reactivation or de novo infection after both solid organ and hematopoietic stem cell transplantation. Antiviral lymphocytes can be selected from apheresis products using the CliniMACS Cytokine-Capture-System® either with the well-established CliniMACS® Plus (Plus device or with its more versatile successor CliniMACS Prodigy® (Prodigy. Methods. Manufacturing of CMV-specific T-cells was carried out with the Prodigy and Plus in parallel starting with 0.8-1*109 leukocytes collected by lymphapheresis (n=3 and using the MACS GMP PepTivator® HCMVpp65 for antigenic re-stimulation. Target and non-target cells were quantified by a newly developed single-platform assessment and gating strategy using positive (CD3/CD4/CD8/CD45/IFN-gamma, negative (CD14/CD19/CD56, and dead cell (7-AAD discriminators. Results. Both devices produced largely similar results for target cell viabilities: 37.2%-52.2% (Prodigy vs. 51.1%-62.1% (Plus CD45+/7-AAD- cells. Absolute numbers of isolated target cells were 0.1-3.8*106 viable IFN-gamma+ CD3+ cells. The corresponding proportions of IFN-gamma+ CD3+ cells ranged between 19.2% and 95.1% among total CD3+ cells and represented recoveries of 41.9%-87.6%. Within two parallel processes predominantly IFN-gamma+ CD3+CD8+ cytotoxic T-cells were enriched compared to one process that yielded a higher amount of IFN-gamma+ CD3+CD4+ helper T lymphocytes. T-cell purity was higher for the Prodigies products that displayed a lower content of contaminating IFN-gamma- T-cells (3.6%-20.8% compared to the Plus products (19.9%-80.0%. Conclusions. The manufacturing process on the Prodigy saved both process and hands-on time due to its higher process integration and ability for unattended operation. Although the usage of both instruments yielded comparable results, the lower content of residual IFN

  12. Circadian clock-mediated regulation of blood pressure.

    Science.gov (United States)

    Douma, Lauren G; Gumz, Michelle L

    2017-12-02

    Most bodily functions vary over the course of a 24h day. Circadian rhythms in body temperature, sleep-wake cycles, metabolism, and blood pressure (BP) are just a few examples. These circadian rhythms are controlled by the central clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and peripheral clocks located throughout the body. Light and food cues entrain these clocks to the time of day and this synchronicity contributes to the regulation of a variety of physiological processes with effects on overall health. The kidney, brain, nervous system, vasculature, and heart have been identified through the use of mouse models and clinical trials as peripheral clock regulators of BP. The dysregulation of this circadian pattern of BP, with or without hypertension, is associated with increased risk for cardiovascular disease. The mechanism of this dysregulation is unknown and is a growing area of research. In this review, we highlight research of human and mouse circadian models that has provided insight into the roles of these molecular clocks and their effects on physiological functions. Additional tissue-specific studies of the molecular clock mechanism are needed, as well as clinical studies including more diverse populations (different races, female patients, etc.), which will be critical to fully understand the mechanism of circadian regulation of BP. Understanding how these molecular clocks regulate the circadian rhythm of BP is critical in the treatment of circadian BP dysregulation and hypertension. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. A fully relativistic definition of the geoid

    Science.gov (United States)

    Laemmerzahl, C.; Hackmann, E.; Perlick, V.; Philipp, D.; Puetzfeld, D.

    2016-12-01

    The present definition of the geoid is based on the Newtonian potential together with the potential related to centrifugal force of the rotating Earth. All time-dependencies due to, e.g., seasonal variations are removed from this definition. The geoid is defined as to be related to the rigid part of the rotating Earth. Upcoming high precision gravimeters and gradiometers as well as optical clocks and clock networks make it necessary to propose a definition of the geoid solely in terms of General Relativity.The new definition of the geoid will be stated within the framework of General Relativity. In this framework we model atomic clocks by standard clocks showing the proper time along their worldline, and we model the Earth in terms of a rigidly rotating gravitating body. The second assumption gives that space-time is equipped with a time-like Killing vector. The norm of this Killing vector is a scalar function which (i) describes the acceleration of freely falling bodies on the surface of the Earth, and (ii) gives the redshift of atomic clocks whose ticking rate can be compared using connecting light rays or optical fibers. It can be shown that in the nonrelativistic limit this generalized potential gives the usual Newtonian potential. Therefore, this scalar function can be taken as the basis for a natural and fully general relativistic generalization of the geoid based on Newtonian gravitational physics. Finally, for certain space-times we will present examples for the geoid.

  14. An Integrative, Multi-Scale Computational Model of a Swimming Lamprey Fully Coupled to Its Fluid Environment and Incorporating Proprioceptive Feedback

    Science.gov (United States)

    Hamlet, C. L.; Hoffman, K.; Fauci, L.; Tytell, E.

    2016-02-01

    The lamprey is a model organism for both neurophysiology and locomotion studies. To study the role of sensory feedback as an organism moves through its environment, a 2D, integrative, multi-scale model of an anguilliform swimmer driven by neural activation from a central pattern generator (CPG) is constructed. The CPG in turn drives muscle kinematics and is fully coupled to the surrounding fluid. The system is numerically evolved in time using an immersed boundary framework producing an emergent swimming mode. Proprioceptive feedback to the CPG based on experimental observations adjust the activation signal as the organism interacts with its environment. Effects on the speed, stability and cost (metabolic work) of swimming due to nonlinear dependencies associated with muscle force development combined with proprioceptive feedback to neural activation are estimated and examined.

  15. KRAS mutation testing in borderline ovarian tumors and low-grade ovarian carcinomas with a rapid, fully integrated molecular diagnostic system.

    Science.gov (United States)

    Sadlecki, Pawel; Antosik, Paulina; Grzanka, Dariusz; Grabiec, Marek; Walentowicz-Sadlecka, Malgorzata

    2017-10-01

    Epithelial ovarian neoplasms are a heterogeneous group of tumors, including various malignancies with distinct clinicopathologic and molecular features. Mutations in BRAF and KRAS genes are the most frequent genetic aberrations found in low-grade serous ovarian carcinomas and serous and mucinous borderline tumors. Implementation of targeted therapeutic strategies requires access to highly specific and highly sensitive diagnostic tests for rapid determination of mutation status. One candidate for such test is fully integrated, real-time polymerase chain reaction-based Idylla™ system for quick and simple detection of KRAS mutations in formaldehyde fixed-paraffin embedded tumor samples. The primary aim of this study was to verify whether fully integrated real-time polymerase chain reaction-based Idylla system may be useful in determination of KRAS mutation status in patients with borderline ovarian tumors and low-grade ovarian carcinomas. The study included tissue specimens from 37 patients with histopathologically verified ovarian masses, operated on at the Department of Obstetrics and Gynecology, Nicolaus Copernicus University Collegium Medicum in Bydgoszcz (Poland) between January 2009 and June 2012. Based on histopathological examination of surgical specimens, 30 lesions were classified as low-grade ovarian carcinomas and 7 as borderline ovarian tumors. Seven patients examined with Idylla KRAS Mutation Test tested positive for KRAS mutation. No statistically significant association was found between the incidence of KRAS mutations and histopathological type of ovarian tumors. Mean survival of the study subjects was 48.51 months (range 3-60 months). Presence of KRAS mutation did not exert a significant effect on the duration of survival in our series. Our findings suggest that Idylla KRAS Mutation Test may be a useful tool for rapid detection of KRAS mutations in ovarian tumor tissue.

  16. CLOCK stabilizes CYCLE to initiate clock function inDrosophila.

    Science.gov (United States)

    Liu, Tianxin; Mahesh, Guruswamy; Yu, Wangjie; Hardin, Paul E

    2017-10-10

    The Drosophila circadian clock keeps time via transcriptional feedback loops. These feedback loops are initiated by CLOCK-CYCLE (CLK-CYC) heterodimers, which activate transcription of genes encoding the feedback repressors PERIOD and TIMELESS. Circadian clocks normally operate in ∼150 brain pacemaker neurons and in many peripheral tissues in the head and body, but can also be induced by expressing CLK in nonclock cells. These ectopic clocks also require cyc , yet CYC expression is restricted to canonical clock cells despite evidence that cyc mRNA is widely expressed. Here we show that CLK binds to and stabilizes CYC in cell culture and in nonclock cells in vivo. Ectopic clocks also require the blue light photoreceptor CRYPTOCHROME (CRY), which is required for both light entrainment and clock function in peripheral tissues. These experiments define the genetic architecture required to initiate circadian clock function in Drosophila , reveal mechanisms governing circadian activator stability that are conserved in perhaps all eukaryotes, and suggest that Clk , cyc , and cry expression is sufficient to drive clock expression in naive cells.

  17. Ascorbic acid surface modified TiO₂-thin layers as a fully integrated analysis system for visual simultaneous detection of organophosphorus pesticides.

    Science.gov (United States)

    Li, Shunxing; Liang, Wenjie; Zheng, Fengying; Lin, Xiaofeng; Cai, Jiabai

    2014-11-06

    TiO₂ photocatalysis and colorimetric detection are coupled with thin layer chromatography (TLC) for the first time to develop a fully integrated analysis system. Titania@polystyrene hybrid microspheres were surface modified with ascorbic acid, denoted AA-TiO₂@PS, and used as the stationary phase for TLC. Because the affinity between AA-TiO₂@PS and organophosphorus pesticides (OPs) was different for different species of OPs (including chlopyrifos, malathion, parathion, parathion-methyl, and methamidophos), OPs could be separated simultaneously by the mobile phase in 12.0 min with different Rf values. After surface modification, the UV-vis wavelength response range of AA-TiO₂@PS was expanded to 650 nm. Under visible-light irradiation, all of the OPs could be photodegraded to PO₄(3-) in 25.0 min. Based on the chromogenic reaction between PO₄(3-) and chromogenic agents (ammonium molybdate and ascorbic acid), OPs were quantified from color intensity images using a scanner in conjunction with image processing software. So, AA-TiO₂@PS was respectively used as the stationary phase of TLC for efficient separation of OPs, as a photocatalyst for species transformation of phosphorus, and as a colorimetric probe for on-field simultaneous visual detection of OPs in natural water. Linear calibration curves for each OP ranged from 19.3 nmol P L(-1) to 2.30 μmol P L(-1). This integrated analysis system was simple, inexpensive, easy to operate, and sensitive.

  18. Verification and Synthesis of Clock-Gated Circuits

    OpenAIRE

    Dai, Yu-Yun

    2017-01-01

    As system complexity and transistor density increase, the power consumed by digital integrated circuits has become a critical constraint for VLSI design and manufacturing.To reduce dynamic power dissipation, clock-gating synthesis techniques are applied to circuits to prune register updates by modifying the next-state functions of the registers. Hence to verify this kind of synthesis, sequential equivalence checking (SEC) of clock-gated circuits is required.In this thesis, we examine the appl...

  19. Circadian Clock, Cancer, and Chemotherapy

    Science.gov (United States)

    2015-01-01

    The circadian clock is a global regulatory system that interfaces with most other regulatory systems and pathways in mammalian organisms. Investigations of the circadian clock–DNA damage response connections have revealed that nucleotide excision repair, DNA damage checkpoints, and apoptosis are appreciably influenced by the clock. Although several epidemiological studies in humans and a limited number of genetic studies in mouse model systems have indicated that clock disruption may predispose mammals to cancer, well-controlled genetic studies in mice have not supported the commonly held view that circadian clock disruption is a cancer risk factor. In fact, in the appropriate genetic background, clock disruption may instead aid in cancer regression by promoting intrinsic and extrinsic apoptosis. Finally, the clock may affect the efficacy of cancer treatment (chronochemotherapy) by modulating the pharmacokinetics and pharmacodynamics of chemotherapeutic drugs as well as the activity of the DNA repair enzymes that repair the DNA damage caused by anticancer drugs. PMID:25302769

  20. Circadian clock and oral cancer.

    Science.gov (United States)

    Nirvani, Minou; Khuu, Cuong; Utheim, Tor Paaske; Sand, Lars Peter; Sehic, Amer

    2018-02-01

    The circadian clock is comprised of a master component situated in the hypothalamic suprachiasmatic nucleus and subordinate clock genes in almost every cell of the body. The circadian clock genes and their encoded proteins govern the organism to follow the natural signals of time, and adapt to external changes in the environment. The majority of physiological processes in mammals exhibit variable circadian rhythms, which are generated and coordinated by an oscillation in the expression of the clock genes. A number of studies have reported that alteration in the expression level of clock genes is correlated with several pathological conditions, including cancer. However, little is known about the role of clock genes in homeostasis of the oral epithelium and their disturbances in oral carcinogenesis. The present review summarizes the current state of knowledge of the implications of clock genes in oral cancer. It has been demonstrated that the development of oral squamous cell carcinoma undergoes circadian oscillation in relation to tumor volume and proliferation rate. The circadian clock gene period ( PER)1 has been associated with oral cancer pathogenesis and it is suggested that changes in the expression of PER1 may exhibit an important role in the development, invasion, and metastasis of oral squamous cell carcinoma. However, its role remains elusive and there is a need for further research in order to understand the underlying mechanisms of the clock genes in oral cancer pathogenesis.

  1. Clocks and special relativity

    International Nuclear Information System (INIS)

    MacRoberts, D.T.

    1980-01-01

    A kinematic theory without precise definitions of the 'space' and 'time' used is an uninterpreted calculus. The definition of 'time' in special relativity is based on light propagation and the 'constant velocity of light' is a tautological consequence of the definition. When this definition is reified in a 'clock' the phenomenon of 'time dilation' occurs, in terms of the defined time, but is not reciprocal between moving systems; the postulate of relativity is not observed. The new definition of time is compatible with an ether theory without the relativity principle. The derivation of the Lorentz transformations, which requires both postulates, is purely formalistic and is not ontologically sound. (Auth.)

  2. Methodologies for steering clocks

    Science.gov (United States)

    Chadsey, Harold

    1995-01-01

    One of the concerns of the PTTI community is the coordination of one time scale with another. This is accomplished through steering one clock system to another, with a goal of a zero or constant offset in time and frequency. In order to attain this goal, rate differences are calculated and allowed for by the steering algorithm. This paper will present several of these different methods of determining rate differences. Ideally, any change in rate should not cause the offset to change sign (overshoot) by any amount, but certainly not by as much as its previous absolute value. The advantages and disadvantages of each depend on the user's situation.

  3. A Light Clock Satisfying the Clock Hypothesis of Special Relativity

    Science.gov (United States)

    West, Joseph

    2007-01-01

    The design of the FMEL, a floor-mirrored Einstein-Langevin "light clock", is introduced. The clock provides a physically intuitive manner to calculate and visualize the time dilation effects for a spatially extended set of observers (an accelerated "frame") undergoing unidirectional acceleration or observers on a rotating cylinder of constant…

  4. Master/slave clock arrangement for providing reliable clock signal

    Science.gov (United States)

    Abbey, Duane L. (Inventor)

    1977-01-01

    The outputs of two like frequency oscillators are combined to form a single reliable clock signal, with one oscillator functioning as a slave under the control of the other to achieve phase coincidence when the master is operative and in a free-running mode when the master is inoperative so that failure of either oscillator produces no effect on the clock signal.

  5. A mixed relaxed clock model

    Science.gov (United States)

    2016-01-01

    Over recent years, several alternative relaxed clock models have been proposed in the context of Bayesian dating. These models fall in two distinct categories: uncorrelated and autocorrelated across branches. The choice between these two classes of relaxed clocks is still an open question. More fundamentally, the true process of rate variation may have both long-term trends and short-term fluctuations, suggesting that more sophisticated clock models unfolding over multiple time scales should ultimately be developed. Here, a mixed relaxed clock model is introduced, which can be mechanistically interpreted as a rate variation process undergoing short-term fluctuations on the top of Brownian long-term trends. Statistically, this mixed clock represents an alternative solution to the problem of choosing between autocorrelated and uncorrelated relaxed clocks, by proposing instead to combine their respective merits. Fitting this model on a dataset of 105 placental mammals, using both node-dating and tip-dating approaches, suggests that the two pure clocks, Brownian and white noise, are rejected in favour of a mixed model with approximately equal contributions for its uncorrelated and autocorrelated components. The tip-dating analysis is particularly sensitive to the choice of the relaxed clock model. In this context, the classical pure Brownian relaxed clock appears to be overly rigid, leading to biases in divergence time estimation. By contrast, the use of a mixed clock leads to more recent and more reasonable estimates for the crown ages of placental orders and superorders. Altogether, the mixed clock introduced here represents a first step towards empirically more adequate models of the patterns of rate variation across phylogenetic trees. This article is part of the themed issue ‘Dating species divergences using rocks and clocks’. PMID:27325829

  6. Ascorbic acid surface modified TiO2-thin layers as a fully integrated analysis system for visual simultaneous detection of organophosphorus pesticides

    Science.gov (United States)

    Li, Shunxing; Liang, Wenjie; Zheng, Fengying; Lin, Xiaofeng; Cai, Jiabai

    2014-11-01

    TiO2 photocatalysis and colorimetric detection are coupled with thin layer chromatography (TLC) for the first time to develop a fully integrated analysis system. Titania@polystyrene hybrid microspheres were surface modified with ascorbic acid, denoted AA-TiO2@PS, and used as the stationary phase for TLC. Because the affinity between AA-TiO2@PS and organophosphorus pesticides (OPs) was different for different species of OPs (including chlopyrifos, malathion, parathion, parathion-methyl, and methamidophos), OPs could be separated simultaneously by the mobile phase in 12.0 min with different Rf values. After surface modification, the UV-vis wavelength response range of AA-TiO2@PS was expanded to 650 nm. Under visible-light irradiation, all of the OPs could be photodegraded to PO43- in 25.0 min. Based on the chromogenic reaction between PO43- and chromogenic agents (ammonium molybdate and ascorbic acid), OPs were quantified from color intensity images using a scanner in conjunction with image processing software. So, AA-TiO2@PS was respectively used as the stationary phase of TLC for efficient separation of OPs, as a photocatalyst for species transformation of phosphorus, and as a colorimetric probe for on-field simultaneous visual detection of OPs in natural water. Linear calibration curves for each OP ranged from 19.3 nmol P L-1 to 2.30 μmol P L-1. This integrated analysis system was simple, inexpensive, easy to operate, and sensitive.TiO2 photocatalysis and colorimetric detection are coupled with thin layer chromatography (TLC) for the first time to develop a fully integrated analysis system. Titania@polystyrene hybrid microspheres were surface modified with ascorbic acid, denoted AA-TiO2@PS, and used as the stationary phase for TLC. Because the affinity between AA-TiO2@PS and organophosphorus pesticides (OPs) was different for different species of OPs (including chlopyrifos, malathion, parathion, parathion-methyl, and methamidophos), OPs could be separated

  7. Machine Learning Helps Identify CHRONO as a Circadian Clock Component

    Science.gov (United States)

    Venkataraman, Anand; Ramanathan, Chidambaram; Kavakli, Ibrahim H.; Hughes, Michael E.; Baggs, Julie E.; Growe, Jacqueline; Liu, Andrew C.; Kim, Junhyong; Hogenesch, John B.

    2014-01-01

    Over the last decades, researchers have characterized a set of “clock genes” that drive daily rhythms in physiology and behavior. This arduous work has yielded results with far-reaching consequences in metabolic, psychiatric, and neoplastic disorders. Recent attempts to expand our understanding of circadian regulation have moved beyond the mutagenesis screens that identified the first clock components, employing higher throughput genomic and proteomic techniques. In order to further accelerate clock gene discovery, we utilized a computer-assisted approach to identify and prioritize candidate clock components. We used a simple form of probabilistic machine learning to integrate biologically relevant, genome-scale data and ranked genes on their similarity to known clock components. We then used a secondary experimental screen to characterize the top candidates. We found that several physically interact with known clock components in a mammalian two-hybrid screen and modulate in vitro cellular rhythms in an immortalized mouse fibroblast line (NIH 3T3). One candidate, Gene Model 129, interacts with BMAL1 and functionally represses the key driver of molecular rhythms, the BMAL1/CLOCK transcriptional complex. Given these results, we have renamed the gene CHRONO (computationally highlighted repressor of the network oscillator). Bi-molecular fluorescence complementation and co-immunoprecipitation demonstrate that CHRONO represses by abrogating the binding of BMAL1 to its transcriptional co-activator CBP. Most importantly, CHRONO knockout mice display a prolonged free-running circadian period similar to, or more drastic than, six other clock components. We conclude that CHRONO is a functional clock component providing a new layer of control on circadian molecular dynamics. PMID:24737000

  8. Centrifugal LabTube platform for fully automated DNA purification and LAMP amplification based on an integrated, low-cost heating system.

    Science.gov (United States)

    Hoehl, Melanie M; Weißert, Michael; Dannenberg, Arne; Nesch, Thomas; Paust, Nils; von Stetten, Felix; Zengerle, Roland; Slocum, Alexander H; Steigert, Juergen

    2014-06-01

    This paper introduces a disposable battery-driven heating system for loop-mediated isothermal DNA amplification (LAMP) inside a centrifugally-driven DNA purification platform (LabTube). We demonstrate LabTube-based fully automated DNA purification of as low as 100 cell-equivalents of verotoxin-producing Escherichia coli (VTEC) in water, milk and apple juice in a laboratory centrifuge, followed by integrated and automated LAMP amplification with a reduction of hands-on time from 45 to 1 min. The heating system consists of two parallel SMD thick film resistors and a NTC as heating and temperature sensing elements. They are driven by a 3 V battery and controlled by a microcontroller. The LAMP reagents are stored in the elution chamber and the amplification starts immediately after the eluate is purged into the chamber. The LabTube, including a microcontroller-based heating system, demonstrates contamination-free and automated sample-to-answer nucleic acid testing within a laboratory centrifuge. The heating system can be easily parallelized within one LabTube and it is deployable for a variety of heating and electrical applications.

  9. Synchronizing clocks in distributed networks

    NARCIS (Netherlands)

    Xia, Weiguo; Cao, Ming

    2011-01-01

    Very recently it has been shown that clocks in distributed networks cannot be synchronized precisely even in idealized situations when asymmetric delays are present [1]. In this paper by determining the clock synchronization errors in the similar settings of the impossibility result just mentioned,

  10. Synchronizing clocks in distributed networks

    NARCIS (Netherlands)

    Xia, Weiguo; Cao, Ming

    2011-01-01

    While various time synchronization protocols for clocks in wired and/or wireless networks are under development, recently it has been shown by Freris, Graham and Kumar that clocks in distributed networks cannot be synchronized precisely even in idealized situations. In this paper by determining the

  11. The circadian clock and asthma.

    Science.gov (United States)

    Durrington, Hannah J; Farrow, Stuart N; Loudon, Andrew S; Ray, David W

    2014-01-01

    It is characteristic of asthma that symptoms worsen overnight, particularly in the early hours of the morning. Nocturnal symptoms in asthma are common and are an important indicator for escalation of treatment. An extensive body of research has demonstrated that nocturnal symptoms of cough and dyspnea are accompanied by circadian variations in airway inflammation and physiologic variables, including airflow limitation and airways hyper-responsiveness. The molecular apparatus that underpins circadian variations, controlled by so called 'clock' genes, has recently been characterised. Clock genes control circadian rhythms both centrally, in the suprachiasmatic nucleus of the brain and peripherally, within every organ of the body. Here, we will discuss how clock genes regulate circadian rhythms. We will focus particularly on the peripheral lung clock and the peripheral immune clock and discuss how these might relate to both the pathogenesis and treatment of asthma.

  12. Linear Approach for Synchronous State Stability in Fully Connected PLL Networks

    Directory of Open Access Journals (Sweden)

    José R. C. Piqueira

    2008-01-01

    Full Text Available Synchronization is an essential feature for the use of digital systems in telecommunication networks, integrated circuits, and manufacturing automation. Formerly, master-slave (MS architectures, with precise master clock generators sending signals to phase-locked loops (PLLs working as slave oscillators, were considered the best solution. Nowadays, the development of wireless networks with dynamical connectivity and the increase of the size and the operation frequency of integrated circuits suggest that the distribution of clock signals could be more efficient if distributed solutions with fully connected oscillators are used. Here, fully connected networks with second-order PLLs as nodes are considered. In previous work, how the synchronous state frequency for this type of network depends on the node parameters and delays was studied and an expression for the long-term frequency was derived (Piqueira, 2006. Here, by taking the first term of the Taylor series expansion for the dynamical system description, it is shown that for a generic network with N nodes, the synchronous state is locally asymptotically stable.

  13. High Precision Clock Bias Prediction Model in Clock Synchronization System

    Directory of Open Access Journals (Sweden)

    Zan Liu

    2016-01-01

    Full Text Available Time synchronization is a fundamental requirement for many services provided by a distributed system. Clock calibration through the time signal is the usual way to realize the synchronization among the clocks used in the distributed system. The interference to time signal transmission or equipment failures may bring about failure to synchronize the time. To solve this problem, a clock bias prediction module is paralleled in the clock calibration system. And for improving the precision of clock bias prediction, the first-order grey model with one variable (GM(1,1 model is proposed. In the traditional GM(1,1 model, the combination of parameters determined by least squares criterion is not optimal; therefore, the particle swarm optimization (PSO is used to optimize GM(1,1 model. At the same time, in order to avoid PSO getting stuck at local optimization and improve its efficiency, the mechanisms that double subgroups and nonlinear decreasing inertia weight are proposed. In order to test the precision of the improved model, we design clock calibration experiments, where time signal is transferred via radio and wired channel, respectively. The improved model is built on the basis of clock bias acquired in the experiments. The results show that the improved model is superior to other models both in precision and in stability. The precision of improved model increased by 66.4%~76.7%.

  14. Simulating Future GPS Clock Scenarios with Two Composite Clock Algorithms

    Science.gov (United States)

    Suess, Matthias; Matsakis, Demetrios; Greenhall, Charles A.

    2010-01-01

    Using the GPS Toolkit, the GPS constellation is simulated using 31 satellites (SV) and a ground network of 17 monitor stations (MS). At every 15-minutes measurement epoch, the monitor stations measure the time signals of all satellites above a parameterized elevation angle. Once a day, the satellite clock estimates the station and satellite clocks. The first composite clock (B) is based on the Brown algorithm, and is now used by GPS. The second one (G) is based on the Greenhall algorithm. The composite clock of G and B performance are investigated using three ground-clock models. Model C simulates the current GPS configuration, in which all stations are equipped with cesium clocks, except for masers at USNO and Alternate Master Clock (AMC) sites. Model M is an improved situation in which every station is equipped with active hydrogen masers. Finally, Models F and O are future scenarios in which the USNO and AMC stations are equipped with fountain clocks instead of masers. Model F is a rubidium fountain, while Model O is more precise but futuristic Optical Fountain. Each model is evaluated using three performance metrics. The timing-related user range error having all satellites available is the first performance index (PI1). The second performance index (PI2) relates to the stability of the broadcast GPS system time itself. The third performance index (PI3) evaluates the stability of the time scales computed by the two composite clocks. A distinction is made between the "Signal-in-Space" accuracy and that available through a GNSS receiver.

  15. Forensic Drug Identification, Confirmation and Quantification Using Fully Integrated Gas Chromatography with Fourier Transform Infrared Detection and Mass Spectrometric Detection (GC-FT-IR-MS).

    Science.gov (United States)

    Lanzarotta, Adam; Lorenz, Lisa; Voelker, Sarah; Falconer, Travis M; Batson, JaCinta S

    2018-01-01

    This manuscript is a continuation of a recent study that described the use of fully integrated gas chromatography with direct deposition Fourier transform infrared detection and mass spectrometric detection (GC-FT-IR-MS) to identify and confirm the presence of sibutramine and AB-FUBINACA. The purpose of the current study was to employ the GC-FT-IR portion of the same instrument to quantify these compounds, thereby demonstrating the ability to identify, confirm, and quantify drug substances using a single GC-FT-IR-MS unit. The performance of the instrument was evaluated by comparing quantitative analytical figures of merit to those measured using an established, widely employed method for quantifying drug substances, high performance liquid chromatography with ultraviolet detection (HPLC-UV). The results demonstrated that GC-FT-IR was outperformed by HPLC-UV with regard to sensitivity, precision, and linear dynamic range (LDR). However, sibutramine and AB-FUBINACA concentrations measured using GC-FT-IR were not significantly different at the 95% confidence interval compared to those measured using HPLC-UV, which demonstrates promise for using GC-FT-IR as a semi-quantitative tool at the very least. The most significant advantage of GC-FT-IR compared to HPLC-UV is selectivity; a higher level of confidence regarding the identity of the analyte being quantified is achieved using GC-FT-IR. Additional advantages of using a single GC-FT-IR-MS instrument for identification, confirmation, and quantification are efficiency, increased sample throughput, decreased consumption of laboratory resources (solvents, chemicals, consumables, etc.), and thus cost.

  16. Fully Automated Simultaneous Integrated Boosted-Intensity Modulated Radiation Therapy Treatment Planning Is Feasible for Head-and-Neck Cancer: A Prospective Clinical Study

    Energy Technology Data Exchange (ETDEWEB)

    Wu Binbin, E-mail: binbin.wu@gunet.georgetown.edu [Department of Radiation Oncology and Molecular Radiation Science, Johns Hopkins University, Baltimore, Maryland (United States); Department of Radiation Medicine, Georgetown University Hospital, Washington, DC (United States); McNutt, Todd [Department of Radiation Oncology and Molecular Radiation Science, Johns Hopkins University, Baltimore, Maryland (United States); Zahurak, Marianna [Department of Oncology Biostatistics, Johns Hopkins University, Baltimore, Maryland (United States); Simari, Patricio [Autodesk Research, Toronto, ON (Canada); Pang, Dalong [Department of Radiation Medicine, Georgetown University Hospital, Washington, DC (United States); Taylor, Russell [Department of Computer Science, Johns Hopkins University, Baltimore, Maryland (United States); Sanguineti, Giuseppe [Department of Radiation Oncology and Molecular Radiation Science, Johns Hopkins University, Baltimore, Maryland (United States)

    2012-12-01

    Purpose: To prospectively determine whether overlap volume histogram (OVH)-driven, automated simultaneous integrated boosted (SIB)-intensity-modulated radiation therapy (IMRT) treatment planning for head-and-neck cancer can be implemented in clinics. Methods and Materials: A prospective study was designed to compare fully automated plans (APs) created by an OVH-driven, automated planning application with clinical plans (CPs) created by dosimetrists in a 3-dose-level (70 Gy, 63 Gy, and 58.1 Gy), head-and-neck SIB-IMRT planning. Because primary organ sparing (cord, brain, brainstem, mandible, and optic nerve/chiasm) always received the highest priority in clinical planning, the study aimed to show the noninferiority of APs with respect to PTV coverage and secondary organ sparing (parotid, brachial plexus, esophagus, larynx, inner ear, and oral mucosa). The sample size was determined a priori by a superiority hypothesis test that had 85% power to detect a 4% dose decrease in secondary organ sparing with a 2-sided alpha level of 0.05. A generalized estimating equation (GEE) regression model was used for statistical comparison. Results: Forty consecutive patients were accrued from July to December 2010. GEE analysis indicated that in APs, overall average dose to the secondary organs was reduced by 1.16 (95% CI = 0.09-2.33) with P=.04, overall average PTV coverage was increased by 0.26% (95% CI = 0.06-0.47) with P=.02 and overall average dose to the primary organs was reduced by 1.14 Gy (95% CI = 0.45-1.8) with P=.004. A physician determined that all APs could be delivered to patients, and APs were clinically superior in 27 of 40 cases. Conclusions: The application can be implemented in clinics as a fast, reliable, and consistent way of generating plans that need only minor adjustments to meet specific clinical needs.

  17. Assessment of the structural integrity of a prototypical instrumented IFMIF high flux test module rig by fully 3D X-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Tiseanu, Ion [National Institute for Laser, Plasma and Radiation Physics, Plasma Physics and Nuclear Fusion Laboratory NILPRP, P.O. Box MG-36, R-77125 Bucharest-Magurele (Romania)], E-mail: tiseanu@infim.ro; Simon, Martin [Hans Waelischmiller GmbH (HWM), Schiessstattweg 16, D-88677 Markdorf (Germany); Craciunescu, Teddy; Mandache, Bogdan N. [National Institute for Laser, Plasma and Radiation Physics, Plasma Physics and Nuclear Fusion Laboratory NILPRP, P.O. Box MG-36, R-77125 Bucharest-Magurele (Romania); Heinzel, Volker; Stratmanns, Erwin; Simakov, Stanislaw P.; Leichtle, Dieter [Forschungszentrum Karlsruhe (FZK), Institut fuer Reaktorsicherheit IRS, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2007-10-15

    An inspection procedure to assess the mechanical integrity of the International Fusion Materials Irradiation Facility (IFMIF) capsules and rigs during the irradiation campaign is necessary. Due to its penetration ability and contrast mechanism, the X-ray microtomography is the only known tool that could meet these requirements. In the high flux test module (HFTM) of IFMIF miniaturized specimens are densely packed in capsules. The capsules, which wear electric heaters and thermocouples, are housed in rigs. To assure a well-defined thermal contact the heater wires have to be attached to the capsules by brazing them into grooves. The examination of the quality of the braze material layer is of crucial interest in order to assure the best heat coupling of the heater wires to the capsule. A high density of the heaters is necessary to maintain the required temperature and, in addition NaK filling of narrow channels is employed for improving the 3D-heat transfer between the irradiation specimens and the capsule wall. Fully 3D tomographic inspections of a prototypical HFTM instrumented capsule, developed and manufactured at FZK, were conducted. In order to identify the optimum irradiation parameters and scanning configuration we carried out a comparative NDT analysis on two microtomography facilities: a compact, high magnification installation at NILPRP and a high-end industrial tomography facility with higher X-ray energy and intensity at HWM. At optimum inspection parameters of a directional microfocus X-ray source (U = 220 kV and I = 300 {mu}A) the geometry resolution was about 30 microns for characteristic dimension of the sample of 50 mm. Voids of 30 microns diameter and cracks of about 20 microns width can be detected. The absolute error of geometrical measurements is sufficient for the assessment of the structural integrity of the irradiation capsule and for the geometry description within the thermal-hydraulic modeling. The space resolution and the overall

  18. Assessment of the structural integrity of a prototypical instrumented IFMIF high flux test module rig by fully 3D X-ray microtomography

    International Nuclear Information System (INIS)

    Tiseanu, Ion; Simon, Martin; Craciunescu, Teddy; Mandache, Bogdan N.; Heinzel, Volker; Stratmanns, Erwin; Simakov, Stanislaw P.; Leichtle, Dieter

    2007-01-01

    An inspection procedure to assess the mechanical integrity of the International Fusion Materials Irradiation Facility (IFMIF) capsules and rigs during the irradiation campaign is necessary. Due to its penetration ability and contrast mechanism, the X-ray microtomography is the only known tool that could meet these requirements. In the high flux test module (HFTM) of IFMIF miniaturized specimens are densely packed in capsules. The capsules, which wear electric heaters and thermocouples, are housed in rigs. To assure a well-defined thermal contact the heater wires have to be attached to the capsules by brazing them into grooves. The examination of the quality of the braze material layer is of crucial interest in order to assure the best heat coupling of the heater wires to the capsule. A high density of the heaters is necessary to maintain the required temperature and, in addition NaK filling of narrow channels is employed for improving the 3D-heat transfer between the irradiation specimens and the capsule wall. Fully 3D tomographic inspections of a prototypical HFTM instrumented capsule, developed and manufactured at FZK, were conducted. In order to identify the optimum irradiation parameters and scanning configuration we carried out a comparative NDT analysis on two microtomography facilities: a compact, high magnification installation at NILPRP and a high-end industrial tomography facility with higher X-ray energy and intensity at HWM. At optimum inspection parameters of a directional microfocus X-ray source (U = 220 kV and I = 300 μA) the geometry resolution was about 30 microns for characteristic dimension of the sample of 50 mm. Voids of 30 microns diameter and cracks of about 20 microns width can be detected. The absolute error of geometrical measurements is sufficient for the assessment of the structural integrity of the irradiation capsule and for the geometry description within the thermal-hydraulic modeling. The space resolution and the overall

  19. Assessment of the Structural Integrity of a Prototypical Instrumented IFMIF High Flux Test Module Rig by Fully 3D X-Ray Microtomography

    International Nuclear Information System (INIS)

    Tiseanu, I.; Craciunescu, T.; Mandache, B.N.; Simon, M.; Heinzel, V.; Stratmanns, E.; Simakov, S.P.; Leichtle, D.

    2006-01-01

    An inspection procedure to asses the mechanical integrity of IFMIF (International Fusion Materials Irradiation Facility) capsules and rigs during the irradiation campaign is necessary. Due to its penetration ability and contrast mechanism, the X-ray micro-tomography is the only known tool that could meet these requirements. In the High Flux Test Module (HFTM) of IFMIF miniaturized specimens are densely packed in capsules. The capsules which wear electric heaters and thermocouples are housed in rigs. To assure a well defined thermal contact the heater wires have to be attached to the capsules by brazing them into grooves. The examination of the quality of the braze material layer is of crucial interest in order to assure the best heat coupling of the heater wires to the capsule. A high density of the heaters is necessary to maintain the required temperature and, in addition NaK filling of narrow channels is employed for improving the 3D-heat transfer between the irradiation specimens and the capsule wall. Fully 3D tomographic inspections of a prototypical HFTM instrumented capsule, developed and manufactures at FZK, were conducted. In order to identify the optimum irradiation parameters and scanning configuration we carried out a comparative NDT analysis on two micro-tomography facilities, our compact, high magnification installation at NILPRP and two high-end industrial tomography facilities with higher X-ray energy and intensity at HWM. At optimum inspection parameters of a microfocus X-ray source (U=220 kV and I=300 μA) the geometry resolution was about 30-50 microns for characteristic dimension of the sample of 50 mm. Voids of 30 microns diameter and cracks of about 20 microns width can be detected. The absolute error of geometrical measurements should be sufficient for the assessment of the structural integrity of the irradiation capsule and for the geometry description within the thermal-hydraulic modeling. Space resolution could be further improved if one

  20. Clock genes, ADHD and aggression.

    Science.gov (United States)

    Mogavero, Floriana; Jager, Amanda; Glennon, Jeffrey C

    2016-11-09

    Attention deficit/hyperactivity disorder (ADHD) is frequently associated with comorbid aggression and sleep disturbances. The sleep/wake cycle is under the control of the circadian system which is moderated by clock genes. Clock genes can regulate the transcription of monoamine oxidase A, which is involved in the degradation of monoamines. Disturbances in monoamine interaction with clock genes in those with monoamine gene polymorphisms may regulate susceptibility of ADHD and comorbid aggression/sleep disturbances. While monoamines influence circadian rhythm and clock gene expression, circadian rhythm components modulate aggressive behavior, and altered clock genes expression have been associated with ADHD. We propose a mechanism by which circadian rhythm and clock gene expression may influence ADHD and comorbid aggression through the modulation of neurotransmitters. The role of clock genes in ADHD patients with comorbid aggression awaits further research; therefore we also indicate directions for future studies to help increase understanding of the underlying mechanisms in ADHD with comorbid aggression and sleep disturbances. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Low Power Clock Network Design

    Directory of Open Access Journals (Sweden)

    Inna Vaisband

    2011-05-01

    Full Text Available Power is a primary concern in modern circuits. Clock distribution networks, in particular, are an essential element of a synchronous digital circuit and a significant power consumer. Clock distribution networks are subject to clock skew due to process, voltage, and temperature (PVT variations and load imbalances. A target skew between sequentially-adjacent registers can be obtained in a balanced low power clock tree using techniques such as buffer and wire sizing. Existing skew mitigation techniques in tree-based clock distribution networks, however, are not efficient in coping with post design variations; whereas the latest non-tree mesh-based solutions reliably handle skew variations, albeit with a significant increase in dissipated power. Alternatively, crosslink-based methods provide low power and variation-efficient skew solutions. Existing crosslink-based methods, however, only address skew at the network topology level and do not target low power consumption. Different methods to manage skew and skew variations within tree and non-tree clock distribution networks are reviewed and compared in this paper. Guidelines for inserting crosslinks within a buffered low power clock tree are provided. Metrics to determine the most power efficient technique for a given circuit are discussed and verified with simulation.

  2. Physiological links of circadian clock and biological clock of aging.

    Science.gov (United States)

    Liu, Fang; Chang, Hung-Chun

    2017-07-01

    Circadian rhythms orchestrate biochemical and physiological processes in living organisms to respond the day/night cycle. In mammals, nearly all cells hold self-sustained circadian clocks meanwhile couple the intrinsic rhythms to systemic changes in a hierarchical manner. The suprachiasmatic nucleus (SCN) of the hypothalamus functions as the master pacemaker to initiate daily synchronization according to the photoperiod, in turn determines the phase of peripheral cellular clocks through a variety of signaling relays, including endocrine rhythms and metabolic cycles. With aging, circadian desynchrony occurs at the expense of peripheral metabolic pathologies and central neurodegenerative disorders with sleep symptoms, and genetic ablation of circadian genes in model organisms resembled the aging-related features. Notably, a number of studies have linked longevity nutrient sensing pathways in modulating circadian clocks. Therapeutic strategies that bridge the nutrient sensing pathways and circadian clock might be rational designs to defy aging.

  3. Minimal tool set for a prokaryotic circadian clock.

    Science.gov (United States)

    Schmelling, Nicolas M; Lehmann, Robert; Chaudhury, Paushali; Beck, Christian; Albers, Sonja-Verena; Axmann, Ilka M; Wiegard, Anika

    2017-07-21

    Circadian clocks are found in organisms of almost all domains including photosynthetic Cyanobacteria, whereby large diversity exists within the protein components involved. In the model cyanobacterium Synechococcus elongatus PCC 7942 circadian rhythms are driven by a unique KaiABC protein clock, which is embedded in a network of input and output factors. Homologous proteins to the KaiABC clock have been observed in Bacteria and Archaea, where evidence for circadian behavior in these domains is accumulating. However, interaction and function of non-cyanobacterial Kai-proteins as well as homologous input and output components remain mainly unclear. Using a universal BLAST analyses, we identified putative KaiC-based timing systems in organisms outside as well as variations within Cyanobacteria. A systematic analyses of publicly available microarray data elucidated interesting variations in circadian gene expression between different cyanobacterial strains, which might be correlated to the diversity of genome encoded clock components. Based on statistical analyses of co-occurrences of the clock components homologous to Synechococcus elongatus PCC 7942, we propose putative networks of reduced and fully functional clock systems. Further, we studied KaiC sequence conservation to determine functionally important regions of diverged KaiC homologs. Biochemical characterization of exemplary cyanobacterial KaiC proteins as well as homologs from two thermophilic Archaea demonstrated that kinase activity is always present. However, a KaiA-mediated phosphorylation is only detectable in KaiC1 orthologs. Our analysis of 11,264 genomes clearly demonstrates that components of the Synechococcus elongatus PCC 7942 circadian clock are present in Bacteria and Archaea. However, all components are less abundant in other organisms than Cyanobacteria and KaiA, Pex, LdpA, and CdpA are only present in the latter. Thus, only reduced KaiBC-based or even simpler, solely KaiC-based timing systems

  4. The central clock neurons regulate lipid storage in Drosophila.

    Directory of Open Access Journals (Sweden)

    Justin R DiAngelo

    Full Text Available A proper balance of lipid breakdown and synthesis is essential for achieving energy homeostasis as alterations in either of these processes can lead to pathological states such as obesity. The regulation of lipid metabolism is quite complex with multiple signals integrated to control overall triglyceride levels in metabolic tissues. Based upon studies demonstrating effects of the circadian clock on metabolism, we sought to determine if the central clock cells in the Drosophila brain contribute to lipid levels in the fat body, the main nutrient storage organ of the fly. Here, we show that altering the function of the Drosophila central clock neurons leads to an increase in fat body triglycerides. We also show that although triglyceride levels are not affected by age, they are increased by expression of the amyloid-beta protein in central clock neurons. The effect on lipid storage seems to be independent of circadian clock output as changes in triglycerides are not always observed in genetic manipulations that result in altered locomotor rhythms. These data demonstrate that the activity of the central clock neurons is necessary for proper lipid storage.

  5. Micro Mercury Ion Clock (MMIC)

    Data.gov (United States)

    National Aeronautics and Space Administration — Demonstrate micro clock based on trapped Hg ions with more than 10x size reduction and power; Fractional frequency stability at parts per 1014 level, adequate for...

  6. Direct regulation of myocardial triglyceride metabolism by the cardiomyocyte circadian clock

    Science.gov (United States)

    Maintenance of circadian alignment between an organism and its environment is essential to ensure metabolic homeostasis. Synchrony is achieved by cell autonomous circadian clocks. Despite a growing appreciation of the integral relation between clocks and metabolism, little is known regarding the dir...

  7. Stochastic models for atomic clocks

    Science.gov (United States)

    Barnes, J. A.; Jones, R. H.; Tryon, P. V.; Allan, D. W.

    1983-01-01

    For the atomic clocks used in the National Bureau of Standards Time Scales, an adequate model is the superposition of white FM, random walk FM, and linear frequency drift for times longer than about one minute. The model was tested on several clocks using maximum likelihood techniques for parameter estimation and the residuals were acceptably random. Conventional diagnostics indicate that additional model elements contribute no significant improvement to the model even at the expense of the added model complexity.

  8. Circadian clock and vascular disease.

    OpenAIRE

    Takeda, Norihiko; Maemura, Koji

    2010-01-01

    Cardiovascular functions, including blood pressure and vascular functions, show diurnal oscillation. Circadian variations have been clearly shown in the occurrence of cardiovascular events such as acute myocardial infarction. Circadian rhythm strongly influences human biology and pathology. The identification and characterization of mammalian clock genes revealed that they are expressed almost everywhere throughout the body in a circadian manner. In contrast to the central clock in the suprac...

  9. Time without clocks - an attempt

    International Nuclear Information System (INIS)

    Karpman, G.

    1978-01-01

    A definition of time intervals separating two states of systems of elementary particles and observers is attempted. The definition is founded on the notion of instant state of the system and uses no information connected with the use of a clock. Applying the definition to a classical clock and to a sample of unstable particles, results are obtained in agreement with experiment. However, if the system contains 'few' elementary particles, the properties of the time interval present some different features. (author)

  10. The retinal clock in mammals: role in health and disease

    Directory of Open Access Journals (Sweden)

    Felder-Schmittbuhl MP

    2017-05-01

    Full Text Available Marie-Paule Felder-Schmittbuhl,1,* Hugo Calligaro,2 Ouria Dkhissi-Benyahya2,* 1Institute of Cellular and Integratives Neurosciences, UPR3212, CNRS, Université de Strasbourg, Strasbourg, 2University of Lyon, Stem Cell and Brain Research Institute, INSERM U1208, Bron, France *These authors contributed equally to this work Abstract: The mammalian retina contains an extraordinary diversity of cell types that are highly organized into precise circuits to perceive and process visual information in a dynamic manner and transmit it to the brain. Above this builds up another level of complex dynamic, orchestrated by a circadian clock located within the retina, which allows retinal physiology, and hence visual function, to adapt to daily changes in light intensity. The mammalian retina is a remarkable model of circadian clock because it harbors photoreception, self-sustained oscillator function, and physiological outputs within the same tissue. However, the location of the retinal clock in mammals has been a matter of long debate. Current data have shown that clock properties are widely distributed among retinal cells and that the retina is composed of a network of circadian clocks located within distinct cellular layers. Nevertheless, the identity of the major pacemaker, if any, still warrants identification. In addition, the retina coordinates rhythmic behavior by providing visual input to the master hypothalamic circadian clock in the suprachiasmatic nuclei (SCN. This light entrainment of the SCN to the light/dark cycle involves a network of retinal photoreceptor cells: rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs. Although it was considered that these photoreceptors synchronized both retinal and SCN clocks, new data challenge this view, suggesting that none of these photoreceptors is involved in photic entrainment of the retinal clock. Because circadian organization is a ubiquitous feature of the retina and controls

  11. Atomic clock ensemble in space (ACES) data analysis

    Science.gov (United States)

    Meynadier, F.; Delva, P.; le Poncin-Lafitte, C.; Guerlin, C.; Wolf, P.

    2018-02-01

    The Atomic Clocks Ensemble in Space (ACES/PHARAO mission, ESA & CNES) will be installed on board the International Space Station (ISS) next year. A crucial part of this experiment is its two-way microwave link (MWL), which will compare the timescale generated on board with those provided by several ground stations disseminated on the Earth. A dedicated data analysis center is being implemented at SYRTE—Observatoire de Paris, where our team currently develops theoretical modelling, numerical simulations and the data analysis software itself. In this paper, we present some key aspects of the MWL measurement method and the associated algorithms for simulations and data analysis. We show the results of tests using simulated data with fully realistic effects such as fundamental measurement noise, Doppler, atmospheric delays, or cycle ambiguities. We demonstrate satisfactory performance of the software with respect to the specifications of the ACES mission. The main scientific product of our analysis is the clock desynchronisation between ground and space clocks, i.e. the difference of proper times between the space clocks and ground clocks at participating institutes. While in flight, this measurement will allow for tests of general relativity and Lorentz invariance at unprecedented levels, e.g. measurement of the gravitational redshift at the 3×10-6 level. As a specific example, we use real ISS orbit data with estimated errors at the 10 m level to study the effect of such errors on the clock desynchronisation obtained from MWL data. We demonstrate that the resulting effects are totally negligible.

  12. The expression of melanopsin and clock genes in Xenopus laevis melanophores and their modulation by melatonin

    Energy Technology Data Exchange (ETDEWEB)

    Bluhm, A.P.C.; Obeid, N.N.; Castrucci, A.M.L.; Visconti, M.A. [Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil)

    2012-05-25

    Vertebrates have a central clock and also several peripheral clocks. Light responses might result from the integration of light signals by these clocks. The dermal melanophores of Xenopus laevis have a photoreceptor molecule denominated melanopsin (OPN4x). The mechanisms of the circadian clock involve positive and negative feedback. We hypothesize that these dermal melanophores also present peripheral clock characteristics. Using quantitative PCR, we analyzed the pattern of temporal expression of Opn4x and the clock genes Per1, Per2, Bmal1, and Clock in these cells subjected to a 14-h light:10-h dark (14L:10D) regime or constant darkness (DD). Also, in view of the physiological role of melatonin in the dermal melanophores of X. laevis, we determined whether melatonin modulates the expression of these clock genes. These genes show a time-dependent expression pattern when these cells are exposed to 14L:10D, which differs from the pattern observed under DD. Cells kept in DD for 5 days exhibited overall increased mRNA expression for Opn4x and Clock, and a lower expression for Per1, Per2, and Bmal1. When the cells were kept in DD for 5 days and treated with melatonin for 1 h, 24 h before extraction, the mRNA levels tended to decrease for Opn4x and Clock, did not change for Bmal1, and increased for Per1 and Per2 at different Zeitgeber times (ZT). Although these data are limited to one-day data collection, and therefore preliminary, we suggest that the dermal melanophores of X. laevis might have some characteristics of a peripheral clock, and that melatonin modulates, to a certain extent, melanopsin and clock gene expression.

  13. The expression of melanopsin and clock genes in Xenopus laevis melanophores and their modulation by melatonin

    International Nuclear Information System (INIS)

    Bluhm, A.P.C.; Obeid, N.N.; Castrucci, A.M.L.; Visconti, M.A.

    2012-01-01

    Vertebrates have a central clock and also several peripheral clocks. Light responses might result from the integration of light signals by these clocks. The dermal melanophores of Xenopus laevis have a photoreceptor molecule denominated melanopsin (OPN4x). The mechanisms of the circadian clock involve positive and negative feedback. We hypothesize that these dermal melanophores also present peripheral clock characteristics. Using quantitative PCR, we analyzed the pattern of temporal expression of Opn4x and the clock genes Per1, Per2, Bmal1, and Clock in these cells subjected to a 14-h light:10-h dark (14L:10D) regime or constant darkness (DD). Also, in view of the physiological role of melatonin in the dermal melanophores of X. laevis, we determined whether melatonin modulates the expression of these clock genes. These genes show a time-dependent expression pattern when these cells are exposed to 14L:10D, which differs from the pattern observed under DD. Cells kept in DD for 5 days exhibited overall increased mRNA expression for Opn4x and Clock, and a lower expression for Per1, Per2, and Bmal1. When the cells were kept in DD for 5 days and treated with melatonin for 1 h, 24 h before extraction, the mRNA levels tended to decrease for Opn4x and Clock, did not change for Bmal1, and increased for Per1 and Per2 at different Zeitgeber times (ZT). Although these data are limited to one-day data collection, and therefore preliminary, we suggest that the dermal melanophores of X. laevis might have some characteristics of a peripheral clock, and that melatonin modulates, to a certain extent, melanopsin and clock gene expression

  14. Circadian clocks, epigenetics, and cancer

    KAUST Repository

    Masri, Selma

    2015-01-01

    The interplay between circadian rhythm and cancer has been suggested for more than a decade based on the observations that shift work and cancer incidence are linked. Accumulating evidence implicates the circadian clock in cancer survival and proliferation pathways. At the molecular level, multiple control mechanisms have been proposed to link circadian transcription and cell-cycle control to tumorigenesis.The circadian gating of the cell cycle and subsequent control of cell proliferation is an area of active investigation. Moreover, the circadian clock is a transcriptional system that is intricately regulated at the epigenetic level. Interestingly, the epigenetic landscape at the level of histone modifications, DNA methylation, and small regulatory RNAs are differentially controlled in cancer cells. This concept raises the possibility that epigenetic control is a common thread linking the clock with cancer, though little scientific evidence is known to date.This review focuses on the link between circadian clock and cancer, and speculates on the possible connections at the epigenetic level that could further link the circadian clock to tumor initiation or progression.

  15. Sound Clocks and Sonic Relativity

    Science.gov (United States)

    Todd, Scott L.; Menicucci, Nicolas C.

    2017-10-01

    Sound propagation within certain non-relativistic condensed matter models obeys a relativistic wave equation despite such systems admitting entirely non-relativistic descriptions. A natural question that arises upon consideration of this is, "do devices exist that will experience the relativity in these systems?" We describe a thought experiment in which `acoustic observers' possess devices called sound clocks that can be connected to form chains. Careful investigation shows that appropriately constructed chains of stationary and moving sound clocks are perceived by observers on the other chain as undergoing the relativistic phenomena of length contraction and time dilation by the Lorentz factor, γ , with c the speed of sound. Sound clocks within moving chains actually tick less frequently than stationary ones and must be separated by a shorter distance than when stationary to satisfy simultaneity conditions. Stationary sound clocks appear to be length contracted and time dilated to moving observers due to their misunderstanding of their own state of motion with respect to the laboratory. Observers restricted to using sound clocks describe a universe kinematically consistent with the theory of special relativity, despite the preferred frame of their universe in the laboratory. Such devices show promise in further probing analogue relativity models, for example in investigating phenomena that require careful consideration of the proper time elapsed for observers.

  16. CIRCADIAN CLOCK-ASSOCIATED 1 Inhibits Leaf Senescence in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Yi Song

    2018-03-01

    Full Text Available Leaf senescence is an integral part of plant development, and the timing and progressing rate of senescence could substantially affect the yield and quality of crops. It has been known that a circadian rhythm synchronized with external environmental cues is critical for the optimal coordination of various physiological and metabolic processes. However, the reciprocal interactions between the circadian clock and leaf senescence in plants remain unknown. Here, through measuring the physiological and molecular senescence related markers of several circadian components mutants, we found that CIRCADIAN CLOCK-ASSOCIATED 1 inhibits leaf senescence. Further molecular and genetic studies revealed that CCA1 directly activates GLK2 and suppresses ORE1 expression to counteract leaf senescence. As plants age, the expression and periodic amplitude of CCA1 declines and thus weakens the inhibition of senescence. Our findings reveal an age-dependent circadian clock component of the process of leaf senescence.

  17. Acting with the Clock: Clocking Practices in Early Childhood

    Science.gov (United States)

    Pacini-Ketchabaw, Veronica

    2012-01-01

    In this article, the author addresses intra-actions that take place among humans and non-human others--the physical world, the materials--in early childhood education's everyday practices. Her object of study is the clock. Specifically, she provides an example of what it might mean to account for the intra-activity of the material-discursive…

  18. Naming analog clocks conceptually facilitates naming digital clocks

    NARCIS (Netherlands)

    Meeuwissen, M.H.W.; Roelofs, A.P.A.; Levelt, W.J.M.

    2004-01-01

    Naming digital clocks (e.g., 2:45, say "quarter to three") requires conceptual operations on the minute and hour information displayed in the input for producing the correct relative time expression. The interplay of these conceptual operations was investigated using a repetition priming paradigm.

  19. Single-transistor-clocked flip-flop

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Peiyi; Darwish, Tarek; Bayoumi, Magdy

    2005-08-30

    The invention provides a low power, high performance flip-flop. The flip-flop uses only one clocked transistor. The single clocked transistor is shared by the first and second branches of the device. A pulse generator produces a clock pulse to trigger the flip-flop. In one preferred embodiment the device can be made as a static explicit pulsed flip-flop which employs only two clocked transistors.

  20. 47 CFR 80.935 - Station clock.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Station clock. 80.935 Section 80.935... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.935 Station clock. Each station subject to this subpart must have a working clock or timepiece readily available to the...

  1. A network of (autonomic) clock outputs

    NARCIS (Netherlands)

    Kalsbeek, A.; Perreau-Lenz, S.; Buijs, R. M.

    2006-01-01

    The circadian clock in the suprachiasmatic nuclei (SCN) is composed of thousands of oscillator neurons, each of which is dependent on the cell-autonomous action of a defined set of circadian clock genes. A major question is still how these individual oscillators are organized into a biological clock

  2. A network of (autonomic) clock outputs

    NARCIS (Netherlands)

    Kalsbeek, A.; Perreau-Lenz, S.; Buijs, R. M.

    2006-01-01

    The circadian clock in the suprachiasmatic nuclei (SCN) is composed of thousands of oscillator neurons, each dependent on the cell-autonomous action of a defined set of circadian clock genes. A major question is still how these individual oscillators are organized into a biological clock that

  3. Gaming in Combinatorial Clock Auctions

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten); V.A. Karamychev (Vladimir)

    2013-01-01

    textabstractIn recent years, Combinatorial Clock Auctions (CCAs) have been used around the world to allocate frequency spectrum for mobile telecom licenses. CCAs are claimed to significantly reduce the scope for gaming or strategic bidding. In this paper, we show, however, that CCAs significantly

  4. Circadian Clocks : Running on Redox

    NARCIS (Netherlands)

    Merrow, Martha; Roenneberg, Till

    2001-01-01

    The circadian clock in all organisms is so intimately linked to light reception that it appears as if evolution has simply wired a timer into the mechanism that processes photic information. Several recent studies have provided new insights into the role of light input pathways in the circadian

  5. Sundials: Ancestors of Our Clocks

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 1. Sundials: Ancestors of Our Clocks. P D Anoop. General Article Volume 16 Issue 1 January 2011 pp 29-37. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/016/01/0029-0037. Keywords. Sundial ...

  6. Teaching by the Body's Clock.

    Science.gov (United States)

    Loviglio, Lorraine

    1981-01-01

    Discusses studies by Donald LaSalle showing that students' performance can vary widely over the day according to the workings of their individual biological clocks. Presents exercises to help children identify their own "body rhythm prime time" and suggests rescheduling instruction to accommodate these differences. Condensed from…

  7. Biological clocks: riding the tides.

    Science.gov (United States)

    de la Iglesia, Horacio O; Johnson, Carl Hirschie

    2013-10-21

    Animals with habitats in the intertidal zone often display biological rhythms that coordinate with both the tidal and the daily environmental cycles. Two recent studies show that the molecular components of the biological clocks mediating tidal rhythms are likely different from the phylogenetically conserved components that mediate circadian (daily) rhythms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. <=ryptochromes and Biological Clocks -36 ...

    Indian Academy of Sciences (India)

    form layer; GL - Gangli- onic layer; OF- Optic nerve fibres). The photorecep- tors for vision are present in rod and cone cells in the outer pig1)Jented epithelial layer, whereas the photo- receptors for the biologi- cal clock are located in the inner nuclear layer of the retina. Pigmented epithelial cell. Vitreous humor. Optic nerve.

  9. An Overview of a Class of Clock Synchronization Algorithms for Wireless Sensor Networks: A Statistical Signal Processing Perspective

    Directory of Open Access Journals (Sweden)

    Xu Wang

    2015-08-01

    Full Text Available Recently, wireless sensor networks (WSNs have drawn great interest due to their outstanding monitoring and management potential in medical, environmental and industrial applications. Most of the applications that employ WSNs demand all of the sensor nodes to run on a common time scale, a requirement that highlights the importance of clock synchronization. The clock synchronization problem in WSNs is inherently related to parameter estimation. The accuracy of clock synchronization algorithms depends essentially on the statistical properties of the parameter estimation algorithms. Recently, studies dedicated to the estimation of synchronization parameters, such as clock offset and skew, have begun to emerge in the literature. The aim of this article is to provide an overview of the state-of-the-art clock synchronization algorithms for WSNs from a statistical signal processing point of view. This article focuses on describing the key features of the class of clock synchronization algorithms that exploit the traditional two-way message (signal exchange mechanism. Upon introducing the two-way message exchange mechanism, the main clock offset estimation algorithms for pairwise synchronization of sensor nodes are first reviewed, and their performance is compared. The class of fully-distributed clock offset estimation algorithms for network-wide synchronization is then surveyed. The paper concludes with a list of open research problems pertaining to clock synchronization of WSNs.

  10. A functional genomics strategy reveals clockwork orange as a transcriptional regulator in the Drosophila circadian clock.

    Science.gov (United States)

    Matsumoto, Akira; Ukai-Tadenuma, Maki; Yamada, Rikuhiro G; Houl, Jerry; Uno, Kenichiro D; Kasukawa, Takeya; Dauwalder, Brigitte; Itoh, Taichi Q; Takahashi, Kuniaki; Ueda, Ryu; Hardin, Paul E; Tanimura, Teiichi; Ueda, Hiroki R

    2007-07-01

    The Drosophila circadian clock consists of integrated autoregulatory feedback loops, making the clock difficult to elucidate without comprehensively identifying the network components in vivo. Previous studies have adopted genome-wide screening for clock-controlled genes using high-density oligonucleotide arrays that identified hundreds of clock-controlled genes. In an attempt to identify the core clock genes among these candidates, we applied genome-wide functional screening using an RNA interference (RNAi) system in vivo. Here we report the identification of novel clock gene candidates including clockwork orange (cwo), a transcriptional repressor belonging to the basic helix-loop-helix ORANGE family. cwo is rhythmically expressed and directly regulated by CLK-CYC through canonical E-box sequences. A genome-wide search for its target genes using the Drosophila genome tiling array revealed that cwo forms its own negative feedback loop and directly suppresses the expression of other clock genes through the E-box sequence. Furthermore, this negative transcriptional feedback loop contributes to sustaining a high-amplitude circadian oscillation in vivo. Based on these results, we propose that the competition between cyclic CLK-CYC activity and the adjustable threshold imposed by CWO keeps E-box-mediated transcription within the controllable range of its activity, thereby rendering a Drosophila circadian clock capable of generating high-amplitude oscillation.

  11. Automatic control of clock duty cycle

    Science.gov (United States)

    Feng, Xiaoxin (Inventor); Roper, Weston (Inventor); Seefeldt, James D. (Inventor)

    2010-01-01

    In general, this disclosure is directed to a duty cycle correction (DCC) circuit that adjusts a falling edge of a clock signal to achieve a desired duty cycle. In some examples, the DCC circuit may generate a pulse in response to a falling edge of an input clock signal, delay the pulse based on a control voltage, adjust the falling edge of the input clock signal based on the delayed pulse to produce an output clock signal, and adjust the control voltage based on the difference between a duty cycle of the output clock signal and a desired duty cycle. Since the DCC circuit adjusts the falling edge of the clock cycle to achieve a desired duty cycle, the DCC may be incorporated into existing PLL control loops that adjust the rising edge of a clock signal without interfering with the operation of such PLL control loops.

  12. Circadian clock, cell cycle and cancer

    Directory of Open Access Journals (Sweden)

    Cansu Özbayer

    2011-12-01

    Full Text Available There are a few rhythms of our daily lives that we are under the influence. One of them is characterized by predictable changes over a 24-hour timescale called circadian clock. This cellular clock is coordinated by the suprachiasmatic nucleus in the anterior hypothalamus. The clock consist of an autoregulatory transcription-translation feedback loop compose of four genes/proteins; BMAL1, Clock, Cyrptochrome, and Period. BMAL 1 and Clock are transcriptional factors and Period and Cyrptochrome are their targets. Period and Cyrptochrome dimerize in the cytoplasm to enter the nucleus where they inhibit Clock/BMAL activity.It has been demonstrate that circadian clock plays an important role cellular proliferation, DNA damage and repair mechanisms, checkpoints, apoptosis and cancer.

  13. Real Time GPS- Satellite Clock Estimation Development of a RTIGS Web Service

    Science.gov (United States)

    Opitz, M.; Weber, R.; Caissy, M.

    2006-12-01

    Since 3 years the IGS (International GNSS Service) Real-Time Working Group disseminates via Internet raw observation data of a subset of stations of the IGS network. This observation data can be used to establish a real-time integrity monitoring of the IGS predicted orbits (Ultra Rapid (IGU-) Orbits) and clocks, according to the recommendations of the IGS Workshop 2004 in Bern. The Institute for "Geodesy and Geophysics" of the TU-Vienna develops in cooperation with the IGS Real-Time Working Group the software "RTR- Control", which currently provides a real-time integrity monitoring of predicted IGU Clock Corrections to GPS Time. Our poster presents the results of a prototype version which is in operation since August this year. Besides RTR-Control allows for the comparison of pseudoranges measured at any permanent station in the global network with theoretical pseudoranges calculated on basis of the IGU- orbits. Thus, the programme can diagnose incorrectly predicted satellite orbits and clocks as well as detect multi-path distorted pseudoranges in real- time. RTR- Control calculates every 15 seconds Satellite Clock Corrections with respect to the most recent IGU- clocks (updated in a 6 hours interval). The clock estimations are referenced to a stable station clock (H-maser) with a small offset to GPS- time. This real-time Satellite Clocks are corrected for individual outliers and modelling errors. The most recent GPS- Satellite Clock Corrections (updated every 60 seconds) are published in Real Time via the Internet. The user group interested in a rigorous integrity monitoring comprises on the one hand the components of IGS itself to qualify the issued orbital data and on the other hand all users of the IGS Ultra Rapid Products (e.g. for PPP in Real Time).

  14. Hanle Detection for Optical Clocks

    Directory of Open Access Journals (Sweden)

    Xiaogang Zhang

    2015-01-01

    Full Text Available Considering the strong inhomogeneous spatial polarization and intensity distribution of spontaneous decay fluorescence due to the Hanle effect, we propose and demonstrate a universe Hanle detection configuration of electron-shelving method for optical clocks. Experimental results from Ca atomic beam optical frequency standard with electron-shelving method show that a designed Hanle detection geometry with optimized magnetic field direction, detection laser beam propagation and polarization direction, and detector position can improve the fluorescence collection rate by more than one order of magnitude comparing with that of inefficient geometry. With the fixed 423 nm fluorescence, the improved 657 nm optical frequency standard signal intensity is presented. The potential application of the Hanle detection geometry designed for facilitating the fluorescence collection for optical lattice clock with a limited solid angle of the fluorescence collection has been discussed. The Hanle detection geometry is also effective for ion detection in ion optical clock and quantum information experiments. Besides, a cylinder fluorescence collection structure is designed to increase the solid angle of the fluorescence collection in Ca atomic beam optical frequency standard.

  15. Clock represses preadipocytes adipogenesis via GILZ.

    Science.gov (United States)

    Zhu, Zhu; Xu, Lirong; Cai, Tingting; Yuan, Gongsheng; Sun, Ning; Lu, Chao; Qian, Ruizhe

    2017-12-26

    Adiposity is a worldwide health threat that needs to be prevented. Circadian gene Clock (circadian locomotor output cycles kaput) is closely correlated to adiposity; for example, weight gain, adipocytes size expansion, and serum lipid level rise in Clock Δ19 mice compared to C57BL/6J mice. However, the precise role of Clock during adipogenic differentiation is unknown. Herein, the circadian gene Clock is shown to regulate adipogenesis mediated by GILZ. Clock-mediated attenuation and upregulation influenced lipid synthesis and affected the levels of adipogenic transcriptional factors, C/EBP-β, C/EBP-α, PPAR-γ, and FABP4, both in vivo and in vitro (primary adipose-derived stromal cells and 3T3-L1 cells). Chromatin immunoprecipitation (ChIP) assay, reporter gene assay, and serum shock assay found that Clock transcriptionally regulated the glucocorticoid-induced leucine zipper (GILZ). Furthermore, GILZ attenuation could relieve the inhibitory effect of Clock on lipid synthesis and GILZ overexpression also reduced the promotion role of Clock attenuation in adipogenesis suggesting that Clock inhibits adipogenic differentiation of preadipocytes via GILZ. The current results demonstrate how circadian genes are likely to regulate adiposity, affecting the adipogenic differentiation process, as well as, increasing the fat cells number. Therefore, this study may provide novel insights into the underlying mechanism explaining the correlation between Clock mutation and adiposity. © 2017 Wiley Periodicals, Inc.

  16. Entanglement of quantum clocks through gravity

    Science.gov (United States)

    Castro Ruiz, Esteban; Giacomini, Flaminia; Brukner, Časlav

    2017-03-01

    In general relativity, the picture of space-time assigns an ideal clock to each world line. Being ideal, gravitational effects due to these clocks are ignored and the flow of time according to one clock is not affected by the presence of clocks along nearby world lines. However, if time is defined operationally, as a pointer position of a physical clock that obeys the principles of general relativity and quantum mechanics, such a picture is, at most, a convenient fiction. Specifically, we show that the general relativistic mass-energy equivalence implies gravitational interaction between the clocks, whereas the quantum mechanical superposition of energy eigenstates leads to a nonfixed metric background. Based only on the assumption that both principles hold in this situation, we show that the clocks necessarily get entangled through time dilation effect, which eventually leads to a loss of coherence of a single clock. Hence, the time as measured by a single clock is not well defined. However, the general relativistic notion of time is recovered in the classical limit of clocks.

  17. Diurnal Preference Predicts Phase Differences in Expression of Human Peripheral Circadian Clock Genes.

    Science.gov (United States)

    Ferrante, Andrew; Gellerman, David; Ay, Ahmet; Woods, Kerri Pruitt; Filipowicz, Allan Michael; Jain, Kriti; Bearden, Neil; Ingram, Krista Kenyon

    2015-06-05

    Circadian rhythms play an integral role in human behavior, physiology and health. Individual differences in daily rhythms (chronotypes) can affect individual sleep-wake cycles, activity patterns and behavioral choices. Diurnal preference, the tendency towards morningness or eveningness among individuals, has been associated with interpersonal variation in circadian clock-related output measures, including body temperature, melatonin levels and clock gene mRNA in blood, oral mucosa, and dermal fibroblast cell cultures. Here we report gene expression data from two principal clock genes sampled from hair follicle cells, a peripheral circadian clock. Hair follicle cells from fourteen individuals of extreme morning or evening chronotype were sampled at three time points. RNA was extracted and quantitative PCR assays were used to measure mRNA expression patterns of two clock genes, Per3 and Nr1d2. We found significant differences in clock gene expression over time between chronotype groups, independent of gender or age of participants. Extreme evening chronotypes have a delay in phase of circadian clock gene oscillation relative to extreme morning types. Variation in the molecular clockwork of chronotype groups represents nearly three-hour phase differences (Per3: 2.61 hours; Nr1d2: 3.08 hours, both: 2.86) in circadian oscillations of these clock genes. The measurement of gene expression from hair follicles at three time points allows for a direct, efficient method of estimating phase shifts of a peripheral circadian clock in real-life conditions. The robust phase differences in temporal expression of clock genes associated with diurnal preferences provide the framework for further studies of the molecular mechanisms and gene-by-environment interactions underlying chronotype-specific behavioral phenomena, including social jetlag.

  18. Mechanism of the circadian clock in physiology

    Science.gov (United States)

    Richards, Jacob

    2013-01-01

    It has been well established that the circadian clock plays a crucial role in the regulation of almost every physiological process. It also plays a critical role in pathophysiological states including those of obesity and diabetes. Recent evidence has highlighted the potential for targeting the circadian clock as a potential drug target. New studies have also demonstrated the existence of “clock-independent effects” of the circadian proteins, leading to exciting new avenues of research in the circadian clock field in physiology. The goal of this review is to provide an introduction to and overview of the circadian clock in physiology, including mechanisms, targets, and role in disease states. The role of the circadian clocks in the regulation of the cardiovascular system, renal function, metabolism, the endocrine system, immune, and reproductive systems will be discussed. PMID:23576606

  19. The Implementation of E1 Clock Recovery

    Directory of Open Access Journals (Sweden)

    Wang Ziyu

    2016-01-01

    Full Text Available Clock transform and recovery is of significant importance in microwave TDM service, and it is always extracted from the E1 line data stream in most cases. However, intrinsically uncertain delay and jitter caused by packet transmission of E1 data information, may lead to the indexes of the data recovery clock exceed the clock performance template. Through analysis of the E1 clock indexes and measuring methods, this paper proposes a new clock recovery method. The method employs two buffers, the first RAM is used as a buffer to deduct excess information, and the second FIFO is used as a buffer to recovery the clock and data. The first buffer has a feedback from the second one, and is able to actively respond to changes in the data link and requests from the second one. The test results validate the effectiveness of the method, and the corresponding scheme is also valuable for the other communication systems.

  20. A 40 GHz fully integrated circuit with a vector network analyzer and a coplanar-line-based detection area for circulating tumor cell analysis using 65 nm CMOS technology

    Science.gov (United States)

    Nakanishi, Taiki; Matsunaga, Maya; Kobayashi, Atsuki; Nakazato, Kazuo; Niitsu, Kiichi

    2018-03-01

    A 40-GHz fully integrated CMOS-based circuit for circulating tumor cells (CTC) analysis, consisting of an on-chip vector network analyzer (VNA) and a highly sensitive coplanar-line-based detection area is presented in this paper. In this work, we introduce a fully integrated architecture that eliminates unwanted parasitic effects. The proposed analyzer was designed using 65 nm CMOS technology, and SPICE and MWS simulations were used to validate its operation. The simulation confirmed that the proposed circuit can measure S-parameter shifts resulting from the addition of various types of tumor cells to the detection area, the data of which are provided in a previous study: the |S 21| values for HepG2, A549, and HEC-1-A cells are -0.683, -0.580, and -0.623 dB, respectively. Additionally, the measurement demonstrated an S-parameters reduction of -25.7% when a silicone resin was put on the circuit. Hence, the proposed system is expected to contribute to cancer diagnosis.

  1. Enabling the democratization of the genomics revolution with a fully integrated web-based bioinformatics platform, Version 1.5 and 1.x.

    Energy Technology Data Exchange (ETDEWEB)

    2017-05-18

    EDGE bioinformatics was developed to help biologists process Next Generation Sequencing data (in the form of raw FASTQ files), even if they have little to no bioinformatics expertise. EDGE is a highly integrated and interactive web-based platform that is capable of running many of the standard analyses that biologists require for viral, bacterial/archaeal, and metagenomic samples. EDGE provides the following analytical workflows: quality trimming and host removal, assembly and annotation, comparisons against known references, taxonomy classification of reads and contigs, whole genome SNP-based phylogenetic analysis, and PCR analysis. EDGE provides an intuitive web-based interface for user input, allows users to visualize and interact with selected results (e.g. JBrowse genome browser), and generates a final detailed PDF report. Results in the form of tables, text files, graphic files, and PDFs can be downloaded. A user management system allows tracking of an individual’s EDGE runs, along with the ability to share, post publicly, delete, or archive their results.

  2. Melatonin, clock genes and mitochondria in sepsis.

    Science.gov (United States)

    Acuña-Castroviejo, Darío; Rahim, Ibtissem; Acuña-Fernández, Carlos; Fernández-Ortiz, Marisol; Solera-Marín, Jorge; Sayed, Ramy K A; Díaz-Casado, María E; Rusanova, Iryna; López, Luis C; Escames, Germaine

    2017-11-01

    After the characterization of the central pacemaker in the suprachiasmatic nucleus, the expression of clock genes was identified in several peripheral tissues including the immune system. The hierarchical control from the central clock to peripheral clocks extends to other functions including endocrine, metabolic, immune, and mitochondrial responses. Increasing evidence links the disruption of the clock genes expression with multiple diseases and aging. Chronodisruption is associated with alterations of the immune system, immunosenescence, impairment of energy metabolism, and reduction of pineal and extrapineal melatonin production. Regarding sepsis, a condition coursing with an exaggerated response of innate immunity, experimental and clinical data showed an alteration of circadian rhythms that reflects the loss of the normal oscillation of the clock. Moreover, recent data point to that some mediators of the immune system affects the normal function of the clock. Under specific conditions, this control disappears reactivating the immune response. So, it seems that clock gene disruption favors the innate immune response, which in turn induces the expression of proinflammatory mediators, causing a further alteration of the clock. Here, the clock control of the mitochondrial function turns off, leading to a bioenergetic decay and formation of reactive oxygen species that, in turn, activate the inflammasome. This arm of the innate immunity is responsible for the huge increase of interleukin-1β and entrance into a vicious cycle that could lead to the death of the patient. The broken clock is recovered by melatonin administration, that is accompanied by the normalization of the innate immunity and mitochondrial homeostasis. Thus, this review emphasizes the connection between clock genes, innate immunity and mitochondria in health and sepsis, and the role of melatonin to maintain clock homeostasis.

  3. The Square Light Clock and Special Relativity

    Science.gov (United States)

    Galli, J. Ronald; Amiri, Farhang

    2012-01-01

    A thought experiment that includes a square light clock is similar to the traditional vertical light beam and mirror clock, except it is made up of four mirrors placed at a 45[degree] angle at each corner of a square of length L[subscript 0], shown in Fig. 1. Here we have shown the events as measured in the rest frame of the square light clock. By…

  4. Local area network distributed realtime clock synchronization

    Science.gov (United States)

    Wilcox, D. R.

    1991-11-01

    This report applies the strobe realtime clock synchronization technique to serial busses and local area networks in general, and to the IEEE 802.5 and the Fiber Distributed Data Interface token ring local area network standards in particular. Section 2 examines miscellaneous material relating to adjustable-rate realtime clocks. Section 3 presents adjustable rate realtime clock hardware implementation methods considered superior to those in an earlier report. Section 4 presents a hardware implementation of an IEEE 802.5 strobe detector.

  5. Distinction between Clock and Time, and a Suggested Experiment with Different Types of Clocks in GPS

    Science.gov (United States)

    Smarandache, Florentin

    2013-03-01

    The clock is an instrument for measuring the time, instrument that may not run perfectly (accurately) under certain conditions (like, say, in strong electromagnetic field, in strong gravitational field, in extremely high or low temperature, pressure, etc.), but this does not mean that time itself runs slower or faster as Einstein's Theory of Relativity asserts. We are referring to an absolute time, i.e. time measured not with respect to ether or non-ether, but with respect to an absolute mathematical reference frame. Several types of clocks could run at a more slowly rate in a moving frame of reference than other types of clocks; it depends on the construction material and functioning principle of each type of clock. Relativists say that ``gravity slows time''. This is incorrect, since actually gravity slows today's types of clocks. And one type of clock is slowed more or less than another type of clock. Not only gravity but other (electric, magnetic, etc.) fields or various medium composition elements or structures may slow or accelerate clocks that are in that medium. The clocks used today in the satellites for the GPS necessitate a correction with respect to the Earth clocks. But in the future, when new types of clocks will be built based on different construction material and functioning principle, the correction of the GPS clocks would be different. In order to make the distinction between ``clock'' and ``time'', we suggest a Experiment # 1 with different types of clocks for the GPS clocks, in order to prove that the resulted dilation and contraction factors are different from those obtained with today's cesium atomic clock.

  6. Song I-Yeong's Armillary Clock

    Science.gov (United States)

    Kim, Sang Hyuk; Lee, Yong Sam

    In 1669 (the 10th year of the reign of King Hyeonjong), Song I-Yeong (宋以穎, 1619-1692), who was a professor of astronomy at Gwansanggam (Bureau of Astronomy), developed the armillary clock which uses the weight power system of an alarm clock. The armillary clock is a unique astronomical clock that combines the traditional armillary sphere of Joseon and the principle of a Western alarm clock. Song I-Yeong's armillary clock was repaired in 1687-1688 according to the records, and since then not much is known about the history of the armillary clock. After many years, in the early 1930s which was the Japanese colonial era, Inchon (仁村) Kim Seong-Su (金性洙, 1891-1955) purchased the armillary clock at the Insa-dong antique street and donated to the Korea University Museum of the present time (designated as National Treasure No. 230 in 1985). Currently, the armillary clock is not in operation because some of the parts are damaged or lost.

  7. Temporal Regulation of Cytokines by the Circadian Clock

    Directory of Open Access Journals (Sweden)

    Atsuhito Nakao

    2014-01-01

    Full Text Available Several parameters of the immune system exhibit oscillations with a period of approximately 24 hours that refers to “circadian rhythms.” Such daily variations in host immune system status might evolve to maximize immune reactions at times when encounters with pathogens are most likely to occur. However, the mechanisms behind circadian immunity have not been fully understood. Recent studies reveal that the internal time keeping system “circadian clock” plays a key role in driving the daily rhythms evident in the immune system. Importantly, several studies unveil molecular mechanisms of how certain clock proteins (e.g., BMAL1 and CLOCK temporally regulate expression of cytokines. Since cytokines are crucial mediators for shaping immune responses, this review mainly summarizes the new knowledge that highlights an emerging role of the circadian clock as a novel regulator of cytokines. A greater understanding of circadian regulation of cytokines will be important to exploit new strategies to protect host against infection by efficient cytokine induction or to treat autoimmunity and allergy by ameliorating excessive activity of cytokines.

  8. Pharao: study of an atomic clock using laser-cooled atoms and realization of a prototype

    International Nuclear Information System (INIS)

    Lemonde, P.

    1997-01-01

    Thermal jets and atomic fountains are two different principles on which atomic clocks are based. In atomic fountains the velocity of atoms can be reduced to a few cm/s so the classical limitations of thermal jets such as phase shift between two Ramsey impulses, second order Doppler effect become negligible. The new limitations set by atomic fountain clocks are now collisions between cold atoms and the radiation emitted by the black body. Weightlessness leads to a different running of the atomic clock and can imply an enhancement of its performances. In micro-gravity an interatomic interaction time of several seconds can be reached. The application of such atomic clocks can go beyond time or frequency metrology. This work is dedicated to the development of a spatial atomic clock to fully use the extremely low velocity of laser-cooled atoms and to quantify what can be expected of weightlessness. This study has involved the realization of a prototype and its testing in a zero-g plane. The experimental results are presented and it is highlighted that an accuracy and a one-day stability of 10 -16 are within reach with an optimized version of this atomic clock. (A.C.)

  9. Agile Blocker and Clock Jitter Tolerant Low-Power Frequency Selective Receiver with Energy Harvesting Capability.

    Science.gov (United States)

    Hasan, Abul; Helaoui, Mohamed; Ghannouchi, Fadhel M

    2017-08-29

    In this article, a novel tunable, blocker and clock jitter tolerant, low power, quadrature phase shift frequency selective (QPS-FS) receiver with energy harvesting capability is proposed. The receiver's design embraces and integrates (i) the baseband to radio frequency (RF) impedance translation concept to improve selectivity over that of conventional homodyne receiver topologies and (ii) broadband quadrature phase shift circuitry in the RF path to remove an active multi-phase clock generation circuit in passive mixer (PM) receivers. The use of a single local oscillator clock signal with a passive clock division network improves the receiver's robustness against clock jitter and reduces the source clock frequency by a factor of N, compared to PM receivers using N switches (N≥4). As a consequence, the frequency coverage of the QPS-FS receiver is improved by a factor of N, given a clock source of maximum frequency; and, the power consumption of the whole receiver system can eventually be reduced. The tunable QPS-FS receiver separates the wanted RF band signal from the unwanted blockers/interferers. The desired RF signal is frequency down-converted to baseband, while the undesired blocker/interferer signals are reflected by the receiver, collected and could be energy recycled using an auxiliary energy harvesting device.

  10. Multiscale Clock Ensembling Using Wavelets

    Science.gov (United States)

    2010-11-01

    allows an energy decomposition of the signal as well, referred to as the wavelet variance. This variance is defined by ) var ()( 2 llX Wv  (11...and it can be shown that for a very wide class of signals and for an appropriately chosen wavelet that ) var ()( 1 2 Xv l lX     . One such...42 nd Annual Precise Time and Time Interval (PTTI) Meeting 527 MULTISCALE CLOCK ENSEMBLING USING WAVELETS Ken Senior Naval Center

  11. Circadian-clock system in mouse liver affected by insulin resistance.

    Science.gov (United States)

    Yang, Shu-Chuan; Tseng, Huey-Lin; Shieh, Kun-Ruey

    2013-07-01

    Circadian rhythms are exhibited in the physiological and behavioral processes of all mammals; they are generated by intracellular levels of circadian oscillators, which are named as a set of circadian-clock genes. These genes compose the transcriptional/translational feedback loops to regulate not only circadian rhythmicity, but also energy metabolism. Previous studies have shown that obesity and diabetes cause the dysregulation of the circadian-clock system, and vice versa. However, some diabetes subjects are lean with insulin resistance and the mechanisms of insulin resistance without obesity are much less well known. Therefore, whether insulin resistance alone is enough to influence the expression of circadian-clock genes is uncertain. This study employs a neonatal streptozotocin (STZ)-treated paradigm in mice to model the molecular and physiological progress of nonobese insulin resistance. A single injection of STZ into 2-d-old male C57BL/6 mice induces nonobese, hyperglycemic and hyperinsulinemic conditions, and the levels of gene expression in the liver by a real-time quantitative polymerase chain reaction are then measured. Although the levels of Bmal1 (brain and muscle Arnt-like protein-1), Per2 (period 2), and Cry1 (cryptochrome 1) mRNA expression in the liver change during the progress of insulin resistance conditions, the gene expression patterns still show circadian rhythmicity. This study suggests that changes in the hepatic circadian-clock gene expression mark an early event in the metabolic disruption associated with insulin resistance. Furthermore, 2 wks of treatment with the thiazolidinedione, pioglitazone, fully resolve the dysfunction in metabolic parameters and the changes in circadian-clock gene expression from early insulin resistance conditions. These results indicate that the circadian-clock system is sensitive to insulin resistance, and that treatment with thiazolidinediones can resolve changes in the circadian-clock system in a timely

  12. Circadian molecular clock in lung pathophysiology

    Science.gov (United States)

    Sundar, Isaac K.; Yao, Hongwei; Sellix, Michael T.

    2015-01-01

    Disrupted daily or circadian rhythms of lung function and inflammatory responses are common features of chronic airway diseases. At the molecular level these circadian rhythms depend on the activity of an autoregulatory feedback loop oscillator of clock gene transcription factors, including the BMAL1:CLOCK activator complex and the repressors PERIOD and CRYPTOCHROME. The key nuclear receptors and transcription factors REV-ERBα and RORα regulate Bmal1 expression and provide stability to the oscillator. Circadian clock dysfunction is implicated in both immune and inflammatory responses to environmental, inflammatory, and infectious agents. Molecular clock function is altered by exposomes, tobacco smoke, lipopolysaccharide, hyperoxia, allergens, bleomycin, as well as bacterial and viral infections. The deacetylase Sirtuin 1 (SIRT1) regulates the timing of the clock through acetylation of BMAL1 and PER2 and controls the clock-dependent functions, which can also be affected by environmental stressors. Environmental agents and redox modulation may alter the levels of REV-ERBα and RORα in lung tissue in association with a heightened DNA damage response, cellular senescence, and inflammation. A reciprocal relationship exists between the molecular clock and immune/inflammatory responses in the lungs. Molecular clock function in lung cells may be used as a biomarker of disease severity and exacerbations or for assessing the efficacy of chronotherapy for disease management. Here, we provide a comprehensive overview of clock-controlled cellular and molecular functions in the lungs and highlight the repercussions of clock disruption on the pathophysiology of chronic airway diseases and their exacerbations. Furthermore, we highlight the potential for the molecular clock as a novel chronopharmacological target for the management of lung pathophysiology. PMID:26361874

  13. Circadian clocks - the fall and rise of physiology

    NARCIS (Netherlands)

    Roenneberg, Till; Merrow, Martha

    2005-01-01

    Circadian clocks control the daily life of most light-sensitive organisms- from cyanobacteria to humans. Molecular processes generate cellular rhythmicity, and cellular clocks in animals coordinate rhythms through interaction ( known as coupling). This hierarchy of clocks generates a complex,

  14. Hierarchical distribution network for low skew and high variation-tolerant bufferless resonant clocking

    International Nuclear Information System (INIS)

    Xu Yi; Chen Shuming; Liu Xiangyuan

    2011-01-01

    We propose a hierarchical interconnection network with two-phase bufferless resonant clock distribution, which mixes the advantages of mesh and tree architectures. The problems of skew reduction and variation-tolerance in the mixed interconnection network are studied through a pipelined multiplier under a TSMC 65 nm standard CMOS process. The post-simulation results show that the hierarchical architecture reduces more than 75% and 65% of clock skew compared with pure mesh and pure H-tree networks, respectively. The maximum skew in the proposed clock distribution is less than 7 ps under imbalanced loading and PVT variations, which is no more than 1% of the clock cycle of about 760 ps. (semiconductor integrated circuits)

  15. A clock synchronization skeleton based on RTAI

    NARCIS (Netherlands)

    Huang, Y.; Visser, P.M.; Broenink, Johannes F.

    2006-01-01

    This paper presents a clock synchronization skeleton based on RTAI (Real Time Application Interface). The skeleton is a thin layer that provides unified but extendible interfaces to the underlying operating system, the synchronization algorithms and the upper level applications in need of clock

  16. Systematic Effects in Atomic Fountain Clocks

    Science.gov (United States)

    Gibble, Kurt

    2016-06-01

    We describe recent advances in the accuracies of atomic fountain clocks. New rigorous treatments of the previously large systematic uncertainties, distributed cavity phase, microwave lensing, and background gas collisions, enabled these advances. We also discuss background gas collisions of optical lattice and ion clocks and derive the smooth transition of the microwave lensing frequency shift to photon recoil shifts for large atomic wave packets.

  17. Internal Clock Drift Estimation in Computer Clusters

    Directory of Open Access Journals (Sweden)

    Hicham Marouani

    2008-01-01

    Full Text Available Most computers have several high-resolution timing sources, from the programmable interrupt timer to the cycle counter. Yet, even at a precision of one cycle in ten millions, clocks may drift significantly in a single second at a clock frequency of several GHz. When tracing the low-level system events in computer clusters, such as packet sending or reception, each computer system records its own events using an internal clock. In order to properly understand the global system behavior and performance, as reported by the events recorded on each computer, it is important to estimate precisely the clock differences and drift between the different computers in the system. This article studies the clock precision and stability of several computer systems, with different architectures. It also studies the typical network delay characteristics, since time synchronization algorithms rely on the exchange of network packets and are dependent on the symmetry of the delays. A very precise clock, based on the atomic time provided by the GPS satellite network, was used as a reference to measure clock drifts and network delays. The results obtained are of immediate use to all applications which depend on computer clocks or network time synchronization accuracy.

  18. Circadian clock components in the rat neocortex

    DEFF Research Database (Denmark)

    Rath, Martin Fredensborg; Rohde, Kristian; Fahrenkrug, Jan

    2013-01-01

    in the rat neocortex. Among these, Per1, Per2, Per3, Cry1, Bmal1, Nr1d1 and Dbp were found to exhibit daily rhythms. The amplitude of circadian oscillation in neocortical clock gene expression was damped and the peak delayed as compared with the SCN. Lesions of the SCN revealed that rhythmic clock gene...

  19. Could Atomic clocks be affected by neutrinos?

    CERN Document Server

    Hanafi, Hanaa

    2016-01-01

    An atomic clock is a clock device that uses an electronic transition frequency of the electromagnetic spectrum of atoms as a frequency standard in order to derive a time standard since time is the reciprocal of frequency. If the electronic transition frequencies are in an "optical region", we are talking in this case about optical atomic clocks. If they are in an "microwave region" these atomic clocks are made of the metallic element cesium so they are called Cesium atomic clocks. Atomic clocks are the most accurate time and frequency standards known despite the different perturbations that can affect them, a lot of researches were made in this domain to show how the transitions can be different for different type of perturbations..Since atomic clocks are very sensitive devices, based on coherent states (A coherent state tends to loose coherence after interacting). One question can arise (from a lot of questions) which is why cosmic neutrinos are not affecting these clocks? The answer to this question requir...

  20. "Molecular Clock" Analogs: A Relative Rates Exercise

    Science.gov (United States)

    Wares, John P.

    2008-01-01

    Although molecular clock theory is a commonly discussed facet of evolutionary biology, undergraduates are rarely presented with the underlying information of how this theory is examined relative to empirical data. Here a simple contextual exercise is presented that not only provides insight into molecular clocks, but is also a useful exercise for…

  1. Design of ternary clocked adiabatic static random access memory

    International Nuclear Information System (INIS)

    Wang Pengjun; Mei Fengna

    2011-01-01

    Based on multi-valued logic, adiabatic circuits and the structure of ternary static random access memory (SRAM), a design scheme of a novel ternary clocked adiabatic SRAM is presented. The scheme adopts bootstrapped NMOS transistors, and an address decoder, a storage cell and a sense amplifier are charged and discharged in the adiabatic way, so the charges stored in the large switch capacitance of word lines, bit lines and the address decoder can be effectively restored to achieve energy recovery during reading and writing of ternary signals. The PSPICE simulation results indicate that the ternary clocked adiabatic SRAM has a correct logic function and low power consumption. Compared with ternary conventional SRAM, the average power consumption of the ternary adiabatic SRAM saves up to 68% in the same conditions. (semiconductor integrated circuits)

  2. Global synchronization of parallel processors using clock pulse width modulation

    Science.gov (United States)

    Chen, Dong; Ellavsky, Matthew R.; Franke, Ross L.; Gara, Alan; Gooding, Thomas M.; Haring, Rudolf A.; Jeanson, Mark J.; Kopcsay, Gerard V.; Liebsch, Thomas A.; Littrell, Daniel; Ohmacht, Martin; Reed, Don D.; Schenck, Brandon E.; Swetz, Richard A.

    2013-04-02

    A circuit generates a global clock signal with a pulse width modification to synchronize processors in a parallel computing system. The circuit may include a hardware module and a clock splitter. The hardware module may generate a clock signal and performs a pulse width modification on the clock signal. The pulse width modification changes a pulse width within a clock period in the clock signal. The clock splitter may distribute the pulse width modified clock signal to a plurality of processors in the parallel computing system.

  3. A clock reaction based on molybdenum blue.

    Science.gov (United States)

    Neuenschwander, Ulrich; Negron, Arnaldo; Jensen, Klavs F

    2013-05-30

    Clock reactions are rare kinetic phenomena, so far limited mostly to systems with ionic oxoacids and oxoanions in water. We report a new clock reaction in cyclohexanol that forms molybdenum blue from a noncharged, yellow molybdenum complex as precursor, in the presence of hydrogen peroxide. Interestingly, the concomitant color change is reversible, enabling multiple clock cycles to be executed consecutively. The kinetics of the clock reaction were experimentally characterized, and by adding insights from quantum chemical calculations, a plausible reaction mechanism was postulated. Key elementary reaction steps comprise sigmatropic rearrangements with five-membered or bicyclo[3.1.0] transition states. Importantly, numerical kinetic modeling demonstrated the mechanism's ability to reproduce the experimental findings. It also revealed that clock behavior is intimately connected to the sudden exhaustion of hydrogen peroxide. Due to the stoichiometric coproduction of ketone, the reaction bears potential for application in alcohol oxidation catalysis.

  4. Fully Digital Chaotic Differential Equation-based Systems And Methods

    KAUST Repository

    Radwan, Ahmed Gomaa Ahmed

    2012-09-06

    Various embodiments are provided for fully digital chaotic differential equation-based systems and methods. In one embodiment, among others, a digital circuit includes digital state registers and one or more digital logic modules configured to obtain a first value from two or more of the digital state registers; determine a second value based upon the obtained first values and a chaotic differential equation; and provide the second value to set a state of one of the plurality of digital state registers. In another embodiment, a digital circuit includes digital state registers, digital logic modules configured to obtain outputs from a subset of the digital shift registers and to provide the input based upon a chaotic differential equation for setting a state of at least one of the subset of digital shift registers, and a digital clock configured to provide a clock signal for operating the digital shift registers.

  5. Android Fully Loaded

    CERN Document Server

    Huddleston, Rob

    2012-01-01

    Fully loaded with the latest tricks and tips on your new Android! Android smartphones are so hot, they're soaring past iPhones on the sales charts. And the second edition of this muscular little book is equally impressive--it's packed with tips and tricks for getting the very most out of your latest-generation Android device. Start Facebooking and tweeting with your Android mobile, scan barcodes to get pricing and product reviews, download your favorite TV shows--the book is positively bursting with practical and fun how-tos. Topics run the gamut from using speech recognition, location-based m

  6. Fully nonlinear elliptic equations

    CERN Document Server

    Caffarelli, Luis A

    1995-01-01

    The goal of the book is to extend classical regularity theorems for solutions of linear elliptic partial differential equations to the context of fully nonlinear elliptic equations. This class of equations often arises in control theory, optimization, and other applications. The authors give a detailed presentation of all the necessary techniques. Instead of treating these techniques in their greatest generality, they outline the key ideas and prove the results needed for developing the subsequent theory. Topics discussed in the book include the theory of viscosity solutions for nonlinear equa

  7. Cell type-specific functions of period genes revealed by novel adipocyte and hepatocyte circadian clock models.

    Directory of Open Access Journals (Sweden)

    Chidambaram Ramanathan

    2014-04-01

    Full Text Available In animals, circadian rhythms in physiology and behavior result from coherent rhythmic interactions between clocks in the brain and those throughout the body. Despite the many tissue specific clocks, most understanding of the molecular core clock mechanism comes from studies of the suprachiasmatic nuclei (SCN of the hypothalamus and a few other cell types. Here we report establishment and genetic characterization of three cell-autonomous mouse clock models: 3T3 fibroblasts, 3T3-L1 adipocytes, and MMH-D3 hepatocytes. Each model is genetically tractable and has an integrated luciferase reporter that allows for longitudinal luminescence recording of rhythmic clock gene expression using an inexpensive off-the-shelf microplate reader. To test these cellular models, we generated a library of short hairpin RNAs (shRNAs against a panel of known clock genes and evaluated their impact on circadian rhythms. Knockdown of Bmal1, Clock, Cry1, and Cry2 each resulted in similar phenotypes in all three models, consistent with previous studies. However, we observed cell type-specific knockdown phenotypes for the Period and Rev-Erb families of clock genes. In particular, Per1 and Per2, which have strong behavioral effects in knockout mice, appear to play different roles in regulating period length and amplitude in these peripheral systems. Per3, which has relatively modest behavioral effects in knockout mice, substantially affects period length in the three cellular models and in dissociated SCN neurons. In summary, this study establishes new cell-autonomous clock models that are of particular relevance to metabolism and suitable for screening for clock modifiers, and reveals previously under-appreciated cell type-specific functions of clock genes.

  8. The Deep Space Atomic Clock: Ushering in a New Paradigm for Radio Navigation and Science

    Science.gov (United States)

    Ely, Todd; Seubert, Jill; Prestage, John; Tjoelker, Robert

    2013-01-01

    The Deep Space Atomic Clock (DSAC) mission will demonstrate the on-orbit performance of a high-accuracy, high-stability miniaturized mercury ion atomic clock during a year-long experiment in Low Earth Orbit. DSAC's timing error requirement provides the frequency stability necessary to perform deep space navigation based solely on one-way radiometric tracking data. Compared to a two-way tracking paradigm, DSAC-enabled one-way tracking will benefit navigation and radio science by increasing the quantity and quality of tracking data. Additionally, DSAC also enables fully-autonomous onboard navigation useful for time-sensitive situations. The technology behind the mercury ion atomic clock and a DSAC mission overview are presented. Example deep space applications of DSAC, including navigation of a Mars orbiter and Europa flyby gravity science, highlight the benefits of DSAC-enabled one-way Doppler tracking.

  9. Fully automated multidimensional reversed-phase liquid chromatography with tandem anion/cation exchange columns for simultaneous global endogenous tyrosine nitration detection, integral membrane protein characterization, and quantitative proteomics mapping in cerebral infarcts.

    Science.gov (United States)

    Quan, Quan; Szeto, Samuel S W; Law, Henry C H; Zhang, Zaijun; Wang, Yuqiang; Chu, Ivan K

    2015-10-06

    Protein tyrosine nitration (PTN) is a signature hallmark of radical-induced nitrative stress in a wide range of pathophysiological conditions, with naturally occurring abundances at substoichiometric levels. In this present study, a fully automated four-dimensional platform, consisting of high-/low-pH reversed-phase dimensions with two additional complementary, strong anion (SAX) and cation exchange (SCX), chromatographic separation stages inserted in tandem, was implemented for the simultaneous mapping of endogenous nitrated tyrosine-containing peptides within the global proteomic context of a Macaca fascicularis cerebral ischemic stroke model. This integrated RP-SA(C)X-RP platform was initially benchmarked through proteomic analyses of Saccharomyces cerevisiae, revealing extended proteome and protein coverage. A total of 27 144 unique peptides from 3684 nonredundant proteins [1% global false discovery rate (FDR)] were identified from M. fascicularis cerebral cortex tissue. The inclusion of the S(A/C)X columns contributed to the increased detection of acidic, hydrophilic, and hydrophobic peptide populations; these separation features enabled the concomitant identification of 127 endogenous nitrated peptides and 137 transmembrane domain-containing peptides corresponding to integral membrane proteins, without the need for specific targeted enrichment strategies. The enhanced diversity of the peptide inventory obtained from the RP-SA(C)X-RP platform also improved analytical confidence in isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analyses.

  10. Single event transient modeling and mitigation techniques for mixed-signal delay locked loop (DLL) and clock circuits

    Science.gov (United States)

    Maillard, Pierre

    The purpose of this PhD work has been to investigate, model, test, develop and provide hardening techniques and guidelines for the mitigation of single event transients (SETs) in analog mixed-signal (AMS) delay locked loops (DLLs) for radiation-hardened applications. Delay-locked-loops (DLLs) are circuit substructures that are present in complex ASIC and system-on-a-chip designs. These circuits are widely used in on-chip clock distribution systems to reduce clock skew, to reduce jitter noise, and to recover clock signals at regional points within a global clock distribution system. DLLs are critical to the performance of many clock distribution systems, and in turn, the overall performance of the associated integrated system; as such, complex systems often employ multiple DLLs for clock deskew and distribution tasks. In radiation environments such as on-orbit, these critical circuits represent at-risk points of malfunction for large sections of integrated circuits due to vulnerabilities to radiation-generated transients (i.e. single event transients) that fan out across the system. The analysis of single event effects in analog DLLs has shown that each DLL sub-circuit primitive is vulnerable to single event transients. However, we have identified the voltage controlled delay line (VCDL) sub-circuit as the most sensitive to radiation-induced single event effects generating missing clock pulses that increase with the operating frequency of the circuit. This vulnerability increases with multiple instantiation of DLLs as clock distribution nodes throughout an integrated system on a chip. To our knowledge, no complete work in the rad-hard community regarding the hardening of mixed-signal DLLs against single event effects (missing pulses) has been developed. Most of the work present in the literature applies the "brute force" and well-established digital technique of triple modular redundancy (TMR) to the digital subcomponents. We have developed two novel design

  11. Clock genes alterations and endocrine disorders.

    Science.gov (United States)

    Angelousi, Anna; Kassi, Eva; Nasiri-Ansari, Narjes; Weickert, Martin O; Randeva, Harpal; Kaltsas, Gregory

    2018-03-25

    Various endocrine signals oscillate over the 24-hour period and so does the responsiveness of target tissues. These daily oscillations do not occur solely in response to external stimuli but are also under the control of an intrinsic circadian clock. We searched the PubMed database to identify studies describing the associations of clock genes with endocrine diseases. Various human single nucleotide polymorphisms of BMAL1 and CLOCK genes exhibited significant associations with type 2 diabetes mellitus. ARNTL2 gene expression and upregulation of BMAL1 and PER1 were associated with the development of type 1 diabetes mellitus. Thyroid hormones modulated PER2 expression in a tissue specific way whereas BMAL1 regulated the expression of type 2 iodothyronine deiodinase in specific tissues. Adrenal gland and adrenal adenoma expressed PER1, PER2, CRY2, CLOCK, and BMAL1 genes. Adrenal sensitivity to adrenocorticotrophin was also affected by circadian oscilliations. A significant correlation between the expression of propio-melanocorticotrophin and PER 2 as well as between prolactin and CLOCK was found in corticotroph and lactosomatotroph cells, respectively, in the pituitary. Clock genes and especially BMAL1 showed an important role in fertility whereas estradiol and androgens exhibited tissue-specific effects on clock gene expression. Metabolic disorders were also associated with circadian dysregulation according to studies in shift workers. Clock genes are associated with various endocrine disorders through complex mechanisms. However data on humans are scarce. Moreover, clock genes exhibit a tissue-specific expression representing an additional level of regulation. Their specific role in endocrine disorders and their potential implications remain to be further clarified. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  12. A fully intraocular high-density self-calibrating epiretinal prosthesis.

    Science.gov (United States)

    Monge, Manuel; Raj, Mayank; Nazari, Meisam Honarvar; Chang, Han-Chieh; Zhao, Yu; Weiland, James D; Humayun, Mark S; Tai, Yu-Chong; Emami, Azita

    2013-12-01

    This paper presents a fully intraocular self-calibrating epiretinal prosthesis with 512 independent channels in 65 nm CMOS. A novel digital calibration technique matches the biphasic currents of each channel independently while the calibration circuitry is shared among every 4 channels. Dual-band telemetry for power and data with on-chip rectifier and clock recovery reduces the number of off-chip components. The rectifier utilizes unidirectional switches to prevent reverse conduction loss in the power transistors and achieves an efficiency > 80%. The data telemetry implements a phase-shift keying (PSK) modulation scheme and supports data rates up to 20 Mb/s. The system occupies an area of 4.5 ×3.1 mm². It features a pixel size of 0.0169 mm² and arbitrary waveform generation per channel. In vitro measurements performed on a Pt/Ir concentric bipolar electrode in phosphate buffered saline (PBS) are presented. A statistical measurement over 40 channels from 5 different chips shows a current mismatch with μ = 1.12 μA and σ = 0.53 μA. The chip is integrated with flexible MEMS origami coils and parylene substrate to provide a fully intraocular implant.

  13. Causes and consequences of hyperexcitation in central clock neurons.

    Directory of Open Access Journals (Sweden)

    Casey O Diekman

    Full Text Available Hyperexcited states, including depolarization block and depolarized low amplitude membrane oscillations (DLAMOs, have been observed in neurons of the suprachiasmatic nuclei (SCN, the site of the central mammalian circadian (~24-hour clock. The causes and consequences of this hyperexcitation have not yet been determined. Here, we explore how individual ionic currents contribute to these hyperexcited states, and how hyperexcitation can then influence molecular circadian timekeeping within SCN neurons. We developed a mathematical model of the electrical activity of SCN neurons, and experimentally verified its prediction that DLAMOs depend on post-synaptic L-type calcium current. The model predicts that hyperexcited states cause high intracellular calcium concentrations, which could trigger transcription of clock genes. The model also predicts that circadian control of certain ionic currents can induce hyperexcited states. Putting it all together into an integrative model, we show how membrane potential and calcium concentration provide a fast feedback that can enhance rhythmicity of the intracellular circadian clock. This work puts forward a novel role for electrical activity in circadian timekeeping, and suggests that hyperexcited states provide a general mechanism for linking membrane electrical dynamics to transcription activation in the nucleus.

  14. Compact atomic clock prototype based on coherent population trapping

    Directory of Open Access Journals (Sweden)

    Danet Jean-Marie

    2014-01-01

    Full Text Available Toward the next generations of compact atomic clocks, clocks based on coherent population trapping (CPT offer a very interesting alternative. Thanks to CPT, a quantum interfering process, this technology has made a decisive step in the miniaturization direction. Fractional frequency stability of 1.5x10-10 at 1 s has been demonstrated in commercial devices of a few cm3. The laboratory prototype presented here intends to explore what could be the ultimate stability of a CPT based device. To do so, an original double-Λ optical scheme and a pulsed interrogation have been implemented in order to get a good compromise between contrast and linewidth. A study of two main sources of noise, the relative intensity and the local oscillator (LO noise, has been performed. By designing simple solutions, it led to a new fractional frequency limitation lower than 4x10-13 at 1 s integration. Such a performance proves that such a technology could rival with classical ones as double resonance clocks.

  15. Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

    Science.gov (United States)

    Affolderbach, C.; Moreno, W.; Ivanov, A. E.; Debogovic, T.; Pellaton, M.; Skrivervik, A. K.; de Rijk, E.; Mileti, G.

    2018-03-01

    Additive manufacturing (AM) of passive microwave components is of high interest for the cost-effective and rapid prototyping or manufacture of devices with complex geometries. Here, we present an experimental study on the properties of recently demonstrated microwave resonator cavities manufactured by AM, in view of their applications to high-performance compact atomic clocks. The microwave cavities employ a loop-gap geometry using six electrodes. The critical electrode structures were manufactured monolithically using two different approaches: Stereolithography (SLA) of a polymer followed by metal coating and Selective Laser Melting (SLM) of aluminum. The tested microwave cavities show the desired TE011-like resonant mode at the Rb clock frequency of ≈6.835 GHz, with a microwave magnetic field highly parallel to the quantization axis across the vapor cell. When operated in an atomic clock setup, the measured atomic Rabi oscillations are comparable to those observed for conventionally manufactured cavities and indicate a good uniformity of the field amplitude across the vapor cell. Employing a time-domain Ramsey scheme on one of the SLA cavities, high-contrast (34%) Ramsey fringes are observed for the Rb clock transition, along with a narrow (166 Hz linewidth) central fringe. The measured clock stability of 2.2 × 10-13 τ-1/2 up to the integration time of 30 s is comparable to the current state-of-the-art stabilities of compact vapor-cell clocks based on conventional microwave cavities and thus demonstrates the feasibility of the approach.

  16. Transcripts from the Circadian Clock: Telling Time and Season

    NARCIS (Netherlands)

    K. Brand (Karl)

    2011-01-01

    textabstractWe all know it when we wake mere moments before an alarm clock is scheduled to wake us: our body clock made the alarm clock redundant. This phenomenon is driven by an endogenous timer known as the biological, or circadian clock. Each revolution of the Earth about its own axis produces

  17. The circadian clock in cancer development and therapy

    Science.gov (United States)

    Most aspects of mammalian function display circadian rhythms driven by an endogenous clock. The circadian clock is operated by genes and comprises a central clock in the brain that responds to environmental cues and controls subordinate clocks in peripheral tissues via circadian output pathways. The...

  18. Regulation of circadian clock transcriptional output by CLOCK:BMAL1.

    Science.gov (United States)

    Trott, Alexandra J; Menet, Jerome S

    2018-01-01

    The mammalian circadian clock relies on the transcription factor CLOCK:BMAL1 to coordinate the rhythmic expression of 15% of the transcriptome and control the daily regulation of biological functions. The recent characterization of CLOCK:BMAL1 cistrome revealed that although CLOCK:BMAL1 binds synchronously to all of its target genes, its transcriptional output is highly heterogeneous. By performing a meta-analysis of several independent genome-wide datasets, we found that the binding of other transcription factors at CLOCK:BMAL1 enhancers likely contribute to the heterogeneity of CLOCK:BMAL1 transcriptional output. While CLOCK:BMAL1 rhythmic DNA binding promotes rhythmic nucleosome removal, it is not sufficient to generate transcriptionally active enhancers as assessed by H3K27ac signal, RNA Polymerase II recruitment, and eRNA expression. Instead, the transcriptional activity of CLOCK:BMAL1 enhancers appears to rely on the activity of ubiquitously expressed transcription factors, and not tissue-specific transcription factors, recruited at nearby binding sites. The contribution of other transcription factors is exemplified by how fasting, which effects several transcription factors but not CLOCK:BMAL1, either decreases or increases the amplitude of many rhythmically expressed CLOCK:BMAL1 target genes. Together, our analysis suggests that CLOCK:BMAL1 promotes a transcriptionally permissive chromatin landscape that primes its target genes for transcription activation rather than directly activating transcription, and provides a new framework to explain how environmental or pathological conditions can reprogram the rhythmic expression of clock-controlled genes.

  19. Clock Drawing in Spatial Neglect: A Comprehensive Analysis of Clock Perimeter, Placement, and Accuracy

    Science.gov (United States)

    Chen, Peii; Goedert, Kelly M.

    2012-01-01

    Clock drawings produced by right-brain-damaged (RBD) individuals with spatial neglect often contain an abundance of empty space on the left while numbers and hands are placed on the right. However, the clock perimeter is rarely compromised in neglect patients’ drawings. By analyzing clock drawings produced by 71 RBD and 40 healthy adults, this study investigated whether the geometric characteristics of the clock perimeter reveal novel insights to understanding spatial neglect. Neglect participants drew smaller clocks than either healthy or non-neglect RBD participants. While healthy participants’ clock perimeter was close to circular, RBD participants drew radially extended ellipses. The mechanisms for these phenomena were investigated by examining the relation between clock-drawing characteristics and performance on six subtests of the Behavioral Inattention Test (BIT). The findings indicated that the clock shape was independent of any BIT subtest or the drawing placement on the test sheet and that the clock size was significantly predicted by one BIT subtest: the poorer the figure and shape copying, the smaller the clock perimeter. Further analyses revealed that in all participants, clocks decreased in size as they were placed farther from the center of the paper. However, even when neglect participants placed their clocks towards the center of the page, they were smaller than those produced by healthy or non-neglect RBD participants. These results suggest a neglect-specific reduction in the subjectively available workspace for graphic production from memory, consistent with the hypothesis that neglect patients are impaired in the ability to enlarge the attentional aperture. PMID:22390278

  20. Circadian and Circalunar Clock Interactions in a Marine Annelid

    Directory of Open Access Journals (Sweden)

    Juliane Zantke

    2013-10-01

    Full Text Available Life is controlled by multiple rhythms. Although the interaction of the daily (circadian clock with environmental stimuli, such as light, is well documented, its relationship to endogenous clocks with other periods is little understood. We establish that the marine worm Platynereis dumerilii possesses endogenous circadian and circalunar (monthly clocks and characterize their interactions. The RNAs of likely core circadian oscillator genes localize to a distinct nucleus of the worm’s forebrain. The worm’s forebrain also harbors a circalunar clock entrained by nocturnal light. This monthly clock regulates maturation and persists even when circadian clock oscillations are disrupted by the inhibition of casein kinase 1δ/ε. Both circadian and circalunar clocks converge on the regulation of transcript levels. Furthermore, the circalunar clock changes the period and power of circadian behavior, although the period length of the daily transcriptional oscillations remains unaltered. We conclude that a second endogenous noncircadian clock can influence circadian clock function.

  1. A GPS Satellite Clock Offset Prediction Method Based on Fitting Clock Offset Rates Data

    Directory of Open Access Journals (Sweden)

    WANG Fuhong

    2016-12-01

    Full Text Available It is proposed that a satellite atomic clock offset prediction method based on fitting and modeling clock offset rates data. This method builds quadratic model or linear model combined with periodic terms to fit the time series of clock offset rates, and computes the model coefficients of trend with the best estimation. The clock offset precisely estimated at the initial prediction epoch is directly adopted to calculate the model coefficient of constant. The clock offsets in the rapid ephemeris (IGR provided by IGS are used as modeling data sets to perform certain experiments for different types of GPS satellite clocks. The results show that the clock prediction accuracies of the proposed method for 3, 6, 12 and 24 h achieve 0.43, 0.58, 0.90 and 1.47 ns respectively, which outperform the traditional prediction method based on fitting original clock offsets by 69.3%, 61.8%, 50.5% and 37.2%. Compared with the IGU real-time clock products provided by IGS, the prediction accuracies of the new method have improved about 15.7%, 23.7%, 27.4% and 34.4% respectively.

  2. Cellular Reprogramming–Turning the Clock Back

    Indian Academy of Sciences (India)

    Cellular Reprogramming - Turning the Clock Back - Nobel Prize in Physiology or Medicine, 2012. Deepa Subramanyam ... Keywords. Embryonic stem cells; pluripotency; reprogramming; differentiation; Nobel Prize 2012. ... National Centre for Cell Science University of Pune Campus Ganeshkhind Pune 411 007, India.

  3. Crime clocks and target performance maps

    CSIR Research Space (South Africa)

    Cooper, Antony K

    1999-12-01

    Full Text Available for the prevention and management of crime. This paper describes two innovative techniques that were developed by CSIR for analysing crime: "crime clocks" and "target performance maps"....

  4. Entrainment of the Neurospora circadian clock

    NARCIS (Netherlands)

    Merrow, M; Boesl, C; Ricken, J; Messerschmitt, M; Goedel, M; Roenneberg, T

    2006-01-01

    Neurospora crassa has been systematically investigated for circadian entrainment behavior. Many aspects of synchronization can be investigated in this simple, cellular system, ranging from systematic entrainment and drivenness to masking. Clock gene expression during entrainment and entrainment

  5. CDDIS_GNSS_products_clocks_rapid

    Data.gov (United States)

    National Aeronautics and Space Administration — Satellite and receiver clock products derived from analysis of Global Navigation Satellite System (GNSS) data. These products are the generated by analysis centers...

  6. Targeting the Circadian Clock to Treat Cancer

    Science.gov (United States)

    Two compounds that target components of the circadian clock killed several types of cancer cells in the lab and slowed the growth of brain cancer in mice without harming healthy cells, as this Cancer Currents post reports.

  7. CDDIS_GNSS_products_clocks_final

    Data.gov (United States)

    National Aeronautics and Space Administration — Satellite and receiver clock products derived from analysis of Global Navigation Satellite System (GNSS) data. These products are the generated by analysis centers...

  8. Clock jitter generator with picoseconds resolution

    Science.gov (United States)

    Jovanović, Goran; Stojčev, Mile; Nikolić, Tatjana

    2013-06-01

    The clock is one of the most critical signals in any synchronous system. As CMOS technology has scaled, supply voltages have dropped chip power consumption has increased and the effects of jitter due to clock frequency increase have become critical and jitter budget has become tighter. This article describes design and development of low-cost mixed-signal programmable jitter generator with high resolution. The digital technique is used for coarse-grain and an analogue technique for fine-grain clock phase shifting. Its structure allows injection of various random and deterministic jitter components in a controllable and programmable fashion. Each jitter component can be switched on or off. The jitter generator can be used in jitter tolerance test and jitter transfer function measurement of high-speed synchronous digital circuits. At operating system clock frequency of 220 MHz, a jitter with 4 ps resolution can be injected.

  9. Draper Clock-Synchronization Protocol in SAL

    Data.gov (United States)

    National Aeronautics and Space Administration — In 1973, Daly, Hpokins, and McKenna (from Draper Lab.) presented a fault-tolerant digital clocking system at the FTCS conference. This is probably one of the first...

  10. Avian Circadian Organization: A Chorus of Clocks

    Science.gov (United States)

    Cassone, Vincent M

    2013-01-01

    In birds, biological clock function pervades all aspects of biology, controlling daily changes in sleep: wake, visual function, song, migratory patterns and orientation, as well as seasonal patterns of reproduction, song and migration. The molecular bases for circadian clocks are highly conserved, and it is likely the avian molecular mechanisms are similar to those expressed in mammals, including humans. The central pacemakers in the avian pineal gland, retinae and SCN dynamically interact to maintain stable phase relationships and then influence downstream rhythms through entrainment of peripheral oscillators in the brain controlling behavior and peripheral tissues. Birds represent an excellent model for the role played by biological clocks in human neurobiology; unlike most rodent models, they are diurnal, they exhibit cognitively complex social interactions, and their circadian clocks are more sensitive to the hormone melatonin than are those of nocturnal rodents. PMID:24157655

  11. Programmable Clock Waveform Generation for CCD Readout

    Energy Technology Data Exchange (ETDEWEB)

    Vicente, J. de; Castilla, J.; Martinez, G.; Marin, J.

    2006-07-01

    Charge transfer efficiency in CCDs is closely related to the clock waveform. In this paper, an experimental framework to explore different FPGA based clock waveform generator designs is described. Two alternative design approaches for controlling the rise/fall edge times and pulse width of the CCD clock signal have been implemented: level-control and time-control. Both approaches provide similar characteristics regarding the edge linearity and noise. Nevertheless, dissimilarities have been found with respect to the area and frequency range of application. Thus, while the time-control approach consumes less area, the level control approach provides a wider range of clock frequencies since it does not suffer capacitor discharge effect. (Author) 8 refs.

  12. The Mechanics of Mechanical Watches and Clocks

    CERN Document Server

    Du, Ruxu

    2013-01-01

    "The Mechanics of Mechanical Watches and Clocks" presents historical views and mathematical models of mechanical watches and clocks. Although now over six hundred years old, mechanical watches and clocks are still popular luxury items that fascinate many people around the world. However few have examined the theory of how they work as presented in this book. The illustrations and computer animations are unique and have never been published before. It will be of significant interest to researchers in mechanical engineering, watchmakers and clockmakers, as well as people who have an engineering background and are interested in mechanical watches and clocks. It will also inspire people in other fields of science and technology, such as mechanical engineering and electronics engineering, to advance their designs. Professor Ruxu Du works at the Chinese University of Hong Kong, China. Assistant Professor Longhan Xie works at the South China University of Technology, China.

  13. Cell-permeable Circadian Clock Proteins

    National Research Council Canada - National Science Library

    Johnson, Carl

    2002-01-01

    .... These 'biological clocks' are important to human physiology. For example, psychiatric and medical studies have shown that circadian rhythmicity is involved in some forms of depressive illness, 'jet lag', drug tolerance/efficacy, memory, and insomnia...

  14. Mini Review: Circadian Clocks, Stress and Immunity

    Directory of Open Access Journals (Sweden)

    Rebecca eDumbell

    2016-05-01

    Full Text Available In mammals, molecular circadian clocks are present in most cells of the body, and this circadian network plays an important role in synchronizing physiological processes and behaviors to the appropriate time of day. The hypothalamic-pituitary-adrenal endocrine axis regulates the response to acute and chronic stress, acting through its final effectors – glucocorticoids – released from the adrenal cortex. Glucocorticoid secretion, characterized by its circadian rhythm, has an important role in synchronizing peripheral clocks and rhythms downstream of the master circadian pacemaker in the suprachiasmatic nucleus. Finally, glucocorticoids are powerfully anti-inflammatory, and recent work has implicated the circadian clock in various aspects and cells of the immune system, suggesting a tight interplay of stress and circadian systems in the regulation of immunity. This mini-review summarizes our current understanding of the role of the circadian clock network in both, the HPA axis and the immune system, and discusses their interactions.

  15. Cellular Reprogramming–Turning the Clock Back

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 6. Cellular Reprogramming - Turning the Clock Back - Nobel Prize in Physiology or Medicine, 2012. Deepa Subramanyam. General Article Volume 18 Issue 6 June 2013 pp 514-521 ...

  16. CDDIS_GNSS_products_clocks_realtime

    Data.gov (United States)

    National Aeronautics and Space Administration — Satellite and receiver clock products derived from analysis of Global Navigation Satellite System (GNSS) data. These products are the generated by analysis centers...

  17. Reduced Kalman Filters for Clock Ensembles

    Science.gov (United States)

    Greenhall, Charles A.

    2011-01-01

    This paper summarizes the author's work ontimescales based on Kalman filters that act upon the clock comparisons. The natural Kalman timescale algorithm tends to optimize long-term timescale stability at the expense of short-term stability. By subjecting each post-measurement error covariance matrix to a non-transparent reduction operation, one obtains corrected clocks with improved short-term stability and little sacrifice of long-term stability.

  18. Molecular components of the mammalian circadian clock

    OpenAIRE

    Buhr, Ethan D.; Takahashi, Joseph S.

    2013-01-01

    Mammals synchronize their circadian activity primarily to the cycles of light and darkness in the environment. This is achieved by ocular photoreception relaying signals to the suprachiasmatic nucleus (SCN) in the hypothalamus. Signals from the SCN cause the synchronization of independent circadian clocks throughout the body to appropriate phases. Signals that can entrain these peripheral clocks include humoral signals, metabolic factors, and body temperature. At the level of individual tissu...

  19. Direct Laser Cooling Al{}^{+} Ion Optical Clocks

    Science.gov (United States)

    Zhang, Jie; Deng, Ke; Luo, Jun; Lu, Ze-Huang

    2017-05-01

    The Al{}+ ion optical clock is a very promising optical frequency standard candidate due to its extremely small black-body radiation shift. It has been successfully demonstrated with the indirect cooled, quantum-logic-based spectroscopy technique. Its accuracy is limited by second-order Doppler shift, and its stability is limited by the number of ions that can be probed in quantum logic processing. We propose a direct laser cooling scheme of Al{}+ ion optical clocks where both the stability and accuracy of the clocks are greatly improved. In the proposed scheme, two Al{}+ traps are utilized. The first trap is used to trap a large number of Al{}+ ions to improve the stability of the clock laser, while the second trap is used to trap a single Al{}+ ion to provide the ultimate accuracy. Both traps are cooled with a continuous wave 167 nm laser. The expected clock laser stability can reach 9.0× {10}-17/\\sqrt{τ }. For the second trap, in addition to 167 nm laser Doppler cooling, a second stage pulsed 234 nm two-photon cooling laser is utilized to further improve the accuracy of the clock laser. The total systematic uncertainty can be reduced to about 1× {10}-18. The proposed Al{}+ ion optical clock has the potential to become the most accurate and stable optical clock. Supported by the National Basic Research Program of China under Grant No 2012CB821300, the National Natural Science Foundation of China under Grant Nos 91336213, 11304109, 91536116 and 11174095, and the Program for New Century Excellent Talents by the Ministry of Education under Grant No NCET-11-0176.

  20. The hepatic circadian clock modulates xenobiotic metabolism in mice

    OpenAIRE

    DeBruyne, Jason P; Weaver, David R; Dallmann, Robert

    2014-01-01

    The circadian clock generates daily cycles of gene expression that regulate physiological processes. The liver plays an important role in xenobiotic metabolism, and also has been shown to possess its own cell-based clock. The liver clock is synchronized by the master clock in the brain, and a portion of rhythmic gene expression can be driven by behavior of the organism as a whole even when the hepatic clock is suppressed. So far, however, there is relatively little evidence indicating whether...

  1. Optical atomic clocks with suppressed black body radiation shift

    OpenAIRE

    Kozlov, Alexander; Dzuba, Vladimir; Flambaum, Victor

    2014-01-01

    We study a wide range of neutral atoms and ions suitable for ultra-precise atomic optical clocks with naturally suppressed black body radiation shift of clock transition frequency. Calculations show that scalar polarizabilities of clock states cancel each other for at least one order of magnitude for considered systems. Results for calculations of frequencies, quadrupole moments of the states, clock transition amplitudes and natural widths of upper clock states are presented.

  2. Fully electric waste collection

    CERN Document Server

    Anaïs Schaeffer

    2015-01-01

    Since 15 June, Transvoirie, which provides waste collection services throughout French-speaking Switzerland, has been using a fully electric lorry for its collections on the CERN site – a first for the region!   Featuring a motor powered by electric batteries that charge up when the brakes are used, the new lorry that roams the CERN site is as green as can be. And it’s not only the motor that’s electric: its waste compactor and lifting mechanism are also electrically powered*, making it the first 100% electric waste collection vehicle in French-speaking Switzerland. Considering that a total of 15.5 tonnes of household waste and paper/cardboard are collected each week from the Meyrin and Prévessin sites, the benefits for the environment are clear. This improvement comes as part of CERN’s contract with Transvoirie, which stipulates that the firm must propose ways of becoming more environmentally friendly (at no extra cost to CERN). *The was...

  3. The Aging Clock and Circadian Control of Metabolism and Genome Stability

    Directory of Open Access Journals (Sweden)

    Victoria P. Belancio

    2015-01-01

    Full Text Available It is widely accepted that aging is characterized by a gradual decline in the efficiency and accuracy of biological processes, leading to deterioration of physiological functions and development of age-associated diseases. Age-dependent accumulation of genomic instability and development of metabolic syndrome are well-recognized components of the aging phenotype, both of which have been extensively studied. Existing findings strongly support the view that the integrity of the cellular genome and metabolic function can be influenced by light at night (LAN and associated suppression of circadian melatonin production. While LAN is reported to accelerate aging by promoting age-associated carcinogenesis in several animal models, the specific molecular mechanism(s of its action are not fully understood. Here, we review literature supporting a connection between LAN-induced central circadian disruption of peripheral circadian rhythms and clock function, LINE-1 retrotransposon-associated genomic instability, metabolic deregulation, and aging. We propose that aging is a progressive decline in the stability, continuity and synchronization of multi-frequency oscillations in biological processes to a temporally disorganized state. By extension, healthy aging is the ability to maintain the most consistent, stable and entrainable rhythmicity and coordination of these oscillations, at the molecular, cellular, and systemic levels.

  4. Do Caucasian and Asian clocks tick differently?

    Directory of Open Access Journals (Sweden)

    A.A. Barbosa

    Full Text Available The Period 3 and Clock genes are important components of the mammalian molecular circadian system. Studies have shown association between polymorphisms in these clock genes and circadian phenotypes in different populations. Nevertheless, differences in the pattern of allele frequency and genotyping distribution are systematically observed in studies with different ethnic groups. To investigate and compare the pattern of distribution in a sample of Asian and Caucasian populations living in Brazil, we evaluated two well-studied polymorphisms in the clock genes: a variable number of tandem repeats (VNTR in PER3 and a single nucleotide polymorphism (SNP in CLOCK. The aim of this investigation was to search for clues about human evolutionary processes related to circadian rhythms. We selected 109 Asian and 135 Caucasian descendants. The frequencies of the shorter allele (4 repeats in the PER3 gene and the T allele in the CLOCK gene among Asians (0.86 and 0.84, respectively were significantly higher than among Caucasians (0.69 and 0.71, respectively. Our results directly confirmed the different distribution of these polymorphisms between the Asian and Caucasian ethnic groups. Given the genetic differences found between groups, two points became evident: first, ethnic variations may have implications for the interpretation of results in circadian rhythm association studies, and second, the question may be raised about which evolutionary conditions shaped these genetic clock variations.

  5. Hydrogen Maser Clock (HMC) Experiment

    Science.gov (United States)

    Vessot, Robert F. C.; Mattison, Edward M.

    1997-01-01

    The Hydrogen Maser Clock (HMC) project was originally conceived to fly on a reflight of the European Space Agency (ESA) free flying platform, the European Recoverable Carrier (EURECA) that had been launched into space and recovered by NASA's Space Transportation System (STS). A Phase B study for operation of HMC as one of the twelve EURECA payload components was begun in July 1991, and completed a year later. Phase C/D of HMC began in August 1992 and continued into early 1995. At that time ESA decided not to refly EURECA, leaving HMC without access to space. Approximately 80% of the flight support electronics are presently operating the HMC's physics package in a vacuum tank at the Smithsonian Astrophysical Observatory, and are now considered to be well-tested flight electronics. The package will continue to be operated until the end of 1997 or until a flight opportunity becomes avaiable. Appendices: letters and trip report; proceedings of the symposium on frequency standards and metrology; milli-celsius-stability thermal control for an orbiting frequency standard.

  6. Fully reflective photon sieve

    Science.gov (United States)

    Sun, Wenbo; Hu, Yongxiang; MacDonnell, David G.; Kim, Hyun Jung; Weimer, Carl; Baize, Rosemary R.

    2018-02-01

    Photon sieves (PS) have many applications and various designs in focusing light. However, a traditional PS only has a light transmissivity up to ∼25% and a focusing efficiency up to ∼7%, which hinder the application of them in many fields, especially for satellite remote sensing. To overcome these inherent drawbacks of traditional PSs, a concept of reflective photon sieve is developed in this work. This reflective photon sieve is based on a transparent membrane backed by a mirror. The transparent membrane is optimally a fully transparent material sheet with given refractive index and designed geometric thickness which has an optical thickness of a quarter incident wavelength (i.e. an anti-reflective coating). The PS-patterned pinholes are made on the transparent membrane. The design makes the light reflected from pinholes and that from zones of membrane material have 180° phase difference. Thus, light incident on this optical device is reflected and focused on its focal point. This device can have a reflectivity of ∼100% and a focusing efficiency of ∼50% based on numerical simulation. This device functions similar to a concave focusing mirror but can preserve the phase feature of light (such as that for the light with orbital angular momentum). It also has excellent wavelength-dependent property, which can exclude most of the undesired light from the focal point. A thin sheet of this component can perform the joint function of lenses and gratings/etalons in the optical path of a remote sensing system, thus is suitable for controling/filtering light in compact instruments such as satellite sensors. This concept is validated by the finite-difference time domain (FDTD) modeling and a lab prototype in this study.

  7. A fully integrated, wide-load-range, high-power-conversion-efficiency switched capacitor DC-DC converter with adaptive bias comparator for ultra-low-power power management integrated circuit

    Science.gov (United States)

    Asano, Hiroki; Hirose, Tetsuya; Kojima, Yuta; Kuroki, Nobutaka; Numa, Masahiro

    2018-04-01

    In this paper, we present a wide-load-range switched-capacitor DC-DC buck converter with an adaptive bias comparator for ultra-low-power power management integrated circuit. The proposed converter is based on a conventional one and modified to operate in a wide load range by developing a load current monitor used in an adaptive bias comparator. Measurement results demonstrated that our proposed converter generates a 1.0 V output voltage from a 3.0 V input voltage at a load of up to 100 µA, which is 20 times higher than that of the conventional one. The power conversion efficiency was higher than 60% in the load range from 0.8 to 100 µA.

  8. Regulation of clock-controlled genes in mammals.

    Directory of Open Access Journals (Sweden)

    Katarzyna Bozek

    Full Text Available The complexity of tissue- and day time-specific regulation of thousands of clock-controlled genes (CCGs suggests that many regulatory mechanisms contribute to the transcriptional output of the circadian clock. We aim to predict these mechanisms using a large scale promoter analysis of CCGs.Our study is based on a meta-analysis of DNA-array data from rodent tissues. We searched in the promoter regions of 2065 CCGs for highly overrepresented transcription factor binding sites. In order to compensate the relatively high GC-content of CCG promoters, a novel background model to avoid a bias towards GC-rich motifs was employed. We found that many of the transcription factors with overrepresented binding sites in CCG promoters exhibit themselves circadian rhythms. Among the predicted factors are known regulators such as CLOCKratioBMAL1, DBP, HLF, E4BP4, CREB, RORalpha and the recently described regulators HSF1, STAT3, SP1 and HNF-4alpha. As additional promising candidates of circadian transcriptional regulators PAX-4, C/EBP, EVI-1, IRF, E2F, AP-1, HIF-1 and NF-Y were identified. Moreover, GC-rich motifs (SP1, EGR, ZF5, AP-2, WT1, NRF-1 and AT-rich motifs (MEF-2, HMGIY, HNF-1, OCT-1 are significantly overrepresented in promoter regions of CCGs. Putative tissue-specific binding sites such as HNF-3 for liver, NKX2.5 for heart or Myogenin for skeletal muscle were found. The regulation of the erythropoietin (Epo gene was analysed, which exhibits many binding sites for circadian regulators. We provide experimental evidence for its circadian regulated expression in the adult murine kidney. Basing on a comprehensive literature search we integrate our predictions into a regulatory network of core clock and clock-controlled genes. Our large scale analysis of the CCG promoters reveals the complexity and extensiveness of the circadian regulation in mammals. Results of this study point to connections of the circadian clock to other functional systems including

  9. The Chemical and Educational Appeal of the Orange Juice Clock

    Science.gov (United States)

    Kelter, Paul B.; Carr, James D.; Johnson, Tanya; Mauricio Castro-Acuña, Carlos

    1996-12-01

    difference between the open circuit voltage (1.772 V) and the voltage with a known resistance (1.037 V). The difference, 1.772 - 1.037 = 0.735 V, equals the product of the circuit current and the resistance of the orange juice (ROJ), or ROJ = 0.735 V/0.001037 A = 708 Ohm 4. Finally, measure the current that the clock itself requires by hooking up in series an ammeter to the battery and the clock. The reading is not easy to take with an ammeter, which does not sample very often, and integrates across time. The computer interface works better for this. In our clock, a current of 0.49 mA was used. 5. The payoff comes at this point. The predicted voltage drop (I x Rint) can be calculated, voltage drop = I x Rint = 0.00049 A x 708 Ohm = 0.35 V Our observed voltage drops for this system were typically around 0.30 V. As a confirmation of the relationship of internal resistance to voltage drop, we placed the strips 1 mm apart in an orange by digging 2 holes in the orange and placing into the holes the coiled parts of the strips. We expected the voltage drop to be much higher than with the juice, due to the much higher internal resistance of the orange. Even when the strips were nearly touching, the drop was about 1 V. The Water Clock We discussed above the difference in the redox system when water is used rather than orange juice. Distilled water, which has a high internal resistance, will not permit the clock to run. However, hard tap water or distilled water with, for example, 1 g of table salt in 300 mL of water will work fine. As expected, because of the lower hydrogen ion concentration, the initial cell voltage is lower, typically around 1.45 V. The clock also ticks more slowly and more softly in water than in orange juice. In water, a black precipitate forms on the magnesium electrode and becomes more extensive with time. When the strip is removed from distilled water, and allowed to dry the precipitate turns white. Further student exploration on the precipitate might include

  10. The clock in the cell : Entrainment of the circadian clock in Neurospora crassa

    NARCIS (Netherlands)

    Madeti Jyothi-Boesl, Cornelia

    2008-01-01

    Since reports of daily leaf movements 2000 years ago, a so-called circadian clock (‘circa diem’ meaning ‘about a day’) has been described in organisms from almost all phyla. The work presented in this thesis gives special emphasis on the circadian clock in the fungus Neurospora crassa, a rather

  11. Sumoylation controls CLOCK-BMAL1-mediated clock resetting via CBP recruitment in nuclear transcriptional foci.

    Science.gov (United States)

    Lee, Yool; Chun, Sung Kook; Kim, Kyungjin

    2015-10-01

    CLOCK-BMAL1 is a key transcription factor complex of the molecular clock system that generates circadian gene expression and physiology in mammals. Here, we demonstrate that sumoylation of BMAL1 mediates the rapid activation of CLOCK-BMAL1 by CREB-binding protein (CBP) in nuclear foci and also the resetting of the circadian clock. Under physiological conditions, a bimolecular fluorescence complementation-based fluorescence resonance energy transfer (BiFC-FRET) assay revealed that CLOCK-BMAL1 rapidly dimerized and formed a ternary complex with CBP in discrete nuclear foci in response to serum stimuli. We found that the formation of this ternary complex requires sumoylation of BMAL1 by SUMO3. These processes were abolished by both the ectopic expression of the SUMP2/3-specific protease, SUSP1, and mutation of the major sumoylation site (Lys259) of BMAL1. Moreover, molecular inhibition of BMAL1 sumoylation abrogated acute Per1 transcription and severely dampened the circadian gene oscillation triggered by clock synchronization stimuli. Taken together, these findings suggest that sumoylation plays a critical role in the spatiotemporal co-activation of CLOCK-BMAL1 by CBP for immediate-early Per induction and the resetting of the circadian clock. Copyright © 2015. Published by Elsevier B.V.

  12. Insulin-FOXO3 signaling modulates circadian rhythms via regulation of clock transcription

    NARCIS (Netherlands)

    Chaves, I.; van der Horst, G.T.J.; Schellevis, R.; Nijman, R.M.; Groot Koerkamp, M.; Holstege, F.C.P.; Smidt, M.P.; Hoekman, M.F.M.

    2014-01-01

    Circadian rhythms are responsive to external and internal cues, light and metabolism being among the most important. In mammals, the light signal is sensed by the retina and transmitted to the suprachiasmatic nucleus (SCN) master clock [1], where it is integrated into the molecular oscillator via

  13. A model of guarded recursion with clock synchronisation

    DEFF Research Database (Denmark)

    Bizjak, Aleš; Møgelberg, Rasmus Ejlers

    2015-01-01

    productivity to be captured in types. The calculus uses clocks representing time streams and clock quantifiers which allow limited and controlled elimination of modalities. The calculus has since been extended to dependent types by Møgelberg. Both works give denotational semantics but no rewrite semantics....... In previous versions of this calculus, different clocks represented separate time streams and clock synchronisation was prohibited. In this paper we show that allowing clock synchronisation is safe by constructing a new model of guarded recursion and clocks. This result will greatly simplify the type theory...

  14. Printed Circuit Board Signal Integrity Analysis at CERN: POSTER 1/2 Workshop

    CERN Document Server

    Evans, John

    2001-01-01

    Printed circuit board (PCB) design layout for digital circuits has become a critical issue due to increasing clock frequencies and faster signal switching times. The Cadence SPECCTRAQuest package allows the detailed signal integrity (SI) analysis of designs from the schematic-entry phase to the board level. It is fully integrated into the Cadence PCB design flow and can be used to reduce prototype iterations and improve production robustness. Examples are given on how the tool can help engineers to make design choices and how to optimise board layout for electrical performance. Case studies of work done for LHC detectors are presented.

  15. Printed Circuit Board Signal Integrity Analysis at CERN: POSTER 2/2 Workshop

    CERN Document Server

    Evans, John

    2001-01-01

    Printed circuit board (PCB) design layout for digital circuits has become a critical issue due to increasing clock frequencies and faster signal switching times. The Cadence SPECCTRAQuest package allows the detailed signal integrity (SI) analysis of designs from the schematic-entry phase to the board level. It is fully integrated into the Cadence PCB design flow and can be used to reduce prototype iterations and improve production robustness. Examples are given on how the tool can help engineers to make design choices and how to optimise board layout for electrical performance. Case studies of work done for LHC detectors are presented.

  16. Extended Coherence Time on the Clock Transition of Optically Trapped Rubidium

    DEFF Research Database (Denmark)

    Kleine Büning, G.; Will, J.; Ertmer, W.

    2011-01-01

    Optically trapped ensembles are of crucial importance for frequency measurements and quantum memories but generally suffer from strong dephasing due to inhomogeneous density and light shifts. We demonstrate a drastic increase of the coherence time to 21 s on the magnetic field insensitive clock...... transition of 87Rb by applying the recently discovered spin self-rephasing [C. Deutsch et al., Phys. Rev. Lett. 105, 020401 (2010)]. This result confirms the general nature of this new mechanism and thus shows its applicability in atom clocks and quantum memories. A systematic investigation of all relevant...... frequency shifts and noise contributions yields a stability of 2.4×10-11τ-1/2, where τ is the integration time in seconds. Based on a set of technical improvements, the presented frequency standard is predicted to rival the stability of microwave fountain clocks in a potentially much more compact setup....

  17. Sugars, the clock and transition to flowering

    Directory of Open Access Journals (Sweden)

    Mohammad Reza eBolouri Moghaddam

    2013-02-01

    Full Text Available Sugars do not only act as source of energy, but they also act as signals in plants. This mini review summarizes the emerging links between sucrose-mediated signaling and the cellular networks involved in flowering time control and defense. Cross-talks with gibberellin (GA and jasmonate (JA signaling pathways are highlighted. The circadian clock fulfills a crucial role at the heart of cellular networks and the bilateral relation between sugar signaling and the clock is discussed. It is proposed that important factors controlling plant growth (DELLAs, PIFs, invertases and trehalose- 6-phosphate or T6P might fulfill central roles in the transition to flowering as well. The emerging concept of ‘sweet immunity’, modulated by the clock, might at least partly rely on a sucrose-specific signaling pathway that needs further exploration.

  18. Sample-Clock Phase-Control Feedback

    Science.gov (United States)

    Quirk, Kevin J.; Gin, Jonathan W.; Nguyen, Danh H.; Nguyen, Huy

    2012-01-01

    To demodulate a communication signal, a receiver must recover and synchronize to the symbol timing of a received waveform. In a system that utilizes digital sampling, the fidelity of synchronization is limited by the time between the symbol boundary and closest sample time location. To reduce this error, one typically uses a sample clock in excess of the symbol rate in order to provide multiple samples per symbol, thereby lowering the error limit to a fraction of a symbol time. For systems with a large modulation bandwidth, the required sample clock rate is prohibitive due to current technological barriers and processing complexity. With precise control of the phase of the sample clock, one can sample the received signal at times arbitrarily close to the symbol boundary, thus obviating the need, from a synchronization perspective, for multiple samples per symbol. Sample-clock phase-control feedback was developed for use in the demodulation of an optical communication signal, where multi-GHz modulation bandwidths would require prohibitively large sample clock frequencies for rates in excess of the symbol rate. A custom mixedsignal (RF/digital) offset phase-locked loop circuit was developed to control the phase of the 6.4-GHz clock that samples the photon-counting detector output. The offset phase-locked loop is driven by a feedback mechanism that continuously corrects for variation in the symbol time due to motion between the transmitter and receiver as well as oscillator instability. This innovation will allow significant improvements in receiver throughput; for example, the throughput of a pulse-position modulation (PPM) with 16 slots can increase from 188 Mb/s to 1.5 Gb/s.

  19. Crime clocks and target performance maps

    CSIR Research Space (South Africa)

    Cooper, Anthony K

    1999-12-01

    Full Text Available View), spreadsheets (eg: Excel) and data bases (eg: Access). 2. Crime clocks A map of crime clocks displays the distribution of crime in time and space using scaled pie charts to show the relative crime rates for the selected period being analysed. Each... pie chart shows the total aggregated crime for an area (eg: CAS Block or precinct) and is positioned on the centroid of the relevant area. Hence, the size of each pie chart is proportional to the amount of crime that occurred in that area over...

  20. Clock frequency estimation under spontaneous emission

    Science.gov (United States)

    Qin, Xi-Zhou; Huang, Jia-Hao; Zhong, Hong-Hua; Lee, Chaohong

    2018-02-01

    We investigate the quantum dynamics of a driven two-level system under spontaneous emission and its application in clock frequency estimation. By using the Lindblad equation to describe the system, we analytically obtain its exact solutions, which show three different regimes: Rabi oscillation, damped oscillation, and overdamped decay. From the analytical solutions, we explore how the spontaneous emission affects the clock frequency estimation. We find that under a moderate spontaneous emission rate, the transition frequency can still be inferred from the Rabi oscillation. Our results enable potential practical applications in frequency measurement and quantum control under decoherence.

  1. Hourly Updated GNSS Orbit and Clock

    Science.gov (United States)

    Song, S.; Xue, J.

    2016-12-01

    With the development of the performance of GNSS, the hourly updated orbit and clock of GNSS are paid much more attention and used by more and more users because of the timeliness and high accuracy. The hourly GNSS orbit and clock are produced routinely in Shanghai Analysis Center(AC) of the International GNSS Monitoring and Assessment Service (iGMAS).In this article, the accuracy of hourly and 6-hourly updated ultra-rapid GPS,GLONASS,GALILEO,BDS orbit and clock (SHU1 and SHU6) are analyzed relative to the final production in detail. The analysis show that, in calculation session, there's no much difference between the mean SHU1 and SHU6 RMS and STD for GNSS orbit and clock. However, for BDS clock in prediction session, the RMS and STD of BDS SHU1 are 2.6ns and 0.5ns respectively, the RMS of BDS SHU6 increase from 2.7ns to 4.5ns from the 1st to the 6th hour prediction session, but there's no much changes of STD. For GPS clock in prediction session, the RMS and STD of GPS SHU1 is quite stable with 0.5ns and 0.2ns.The RMS of GPS SHU6 clock increase from 0.6ns to 1.0ns from the 1st to the 6th hour, but STD is stable at about 0.2ns.For the orbit in calculate session, the RMS of BDS SHU1 is a little less than that of SHU6,the RMS of GPS SHU1 and SHU6 orbit are approximately at the same level. In prediction session, the RMS of IGSO/MEO for BDS SHU1 is relative stable, but the RMS of SHU6 1st-6th hour prediction session increase from about 26.5cm to 32.7cm. The RMS of GPS SHU1 orbit's prediction session is about 3.4cm,but which increase from 3.3cm to 4.3cm for GPS SHU6 1st-6th hour prediction session.The comparison of GLONASS and GALILEO orbit and clock also will be described.The results show that the hourly update is more important for BDS at this stage.Moreover,some problems appearing in satellites and stations can be found earlier by 1 hourly updated frequency.

  2. Clocking Scheme for Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1998-01-01

    A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

  3. Susceptibility of Redundant Versus Singular Clock Domains Implemented in SRAM-Based FPGA TMR Designs

    Science.gov (United States)

    Berg, Melanie D.; LaBel, Kenneth A.; Pellish, Jonathan

    2016-01-01

    We present the challenges that arise when using redundant clock domains due to their clock-skew. Radiation data show that a singular clock domain (DTMR) provides an improved TMR methodology for SRAM-based FPGAs over redundant clocks.

  4. The clock in the cell: Entrainment of the circadian clock in Neurospora crassa

    OpenAIRE

    Madeti Jyothi-Boesl, Cornelia

    2008-01-01

    Since reports of daily leaf movements 2000 years ago, a so-called circadian clock (‘circa diem’ meaning ‘about a day’) has been described in organisms from almost all phyla. The work presented in this thesis gives special emphasis on the circadian clock in the fungus Neurospora crassa, a rather simple cellular system. Neurospora was used to elucidate basic clock mechanisms are that are comparable to those in more complex organisms. To that end, we investigated chronoecological questions as we...

  5. The Effects of the Clock and Kickoff Rule Changes on Actual and Market-Based Expected Scoring in NCAA Football

    Directory of Open Access Journals (Sweden)

    Kenneth Linna

    2014-04-01

    Full Text Available Clock rule changes were introduced in the 2006 season with the goal of reducing the average duration of the game; these changes were reversed in 2007. In addition, in 2007 the kickoff rule was changed to create more excitement and potentially more scoring. We examine what happened to actual and expected scoring during these National Collegiate Athletic Association (NCAA football seasons. The clock rule change in 2006 led to lower scoring which was not fully encompassed in the betting market, leading to significant returns to betting the under. Multiple rule changes in 2007 led to volatility in the betting market that subsided by season’s end.

  6. Pulsed optically pumped atomic clock with zero-dead-time

    Science.gov (United States)

    Lin, Haixiao; Lin, Jinda; Deng, Jianliao; Zhang, Song; Wang, Yuzhu

    2017-12-01

    By alternatively operating two pulsed optically pumped (POP) atomic clocks, the dead time in a single clock can be eliminated, and the local oscillator can be discriminated continuously. A POP atomic clock with a zero-dead-time (ZDT) method is then insensitive to the microwave phase noise. From τ = 0.01 to 1 s, the Allan deviation of the ZDT-POP clock is reduced as nearly τ-1, which is significantly faster than τ-1/2 of a conventional clock. During 1-40 s, the Allan deviation returns to τ-1/2. Moreover, the frequency stability of the ZDT-POP clock is improved by one order of magnitude compared with that of the conventional POP clock. We also analyze the main factors that limit the short-term frequency stability of the POP atomic clock.

  7. Ultracold photodissociation and progress towards a molecular lattice clock with 88 Sr

    Science.gov (United States)

    Lee, Chih-Hsi; McGuyer, Bart; McDonald, Mickey; Apfelback, Florian; Grier, Andrew; Zelevinsky, Tanya

    2016-05-01

    Techniques originally developed for the construction of atomic clocks can be adapted to the study of ultracold molecules, with applications ranging from studies of ultracold chemistry to searches for new physics. We present recent experimental results involving studies of fully quantum state-resolved photodissociation of 88 Sr2 molecules, as well as progress toward building a molecular clock. First, our system has allowed for precise, quantum state-resolved photodissociation studies, revealing not only excellent control over quantum states but also a more accurate way to describe the photodissociation of diatomic molecules and access ultracold chemistry. Second, the molecular clock will allow us to search for a possible time variation of the proton-electron mass ratio. The ``oscillator'' of such a molecular clock would consist of the frequency difference between two lasers driving a two-photon Raman transition between deeply and intermediately-bound rovibrational levels in the electronic ground state. Accomplishing this task requires exploring several research directions, including the precision spectroscopy of bound states and developing tools for the control and minimization of differential lattice light shifts.

  8. Clock Synchronization for Multi-hop Ad hoc Networks

    OpenAIRE

    O'Connor, Neil

    2003-01-01

    Clock syncronization is one of the basic requirements of a distributed real-time systems. The greater the precision achievable by the clock synchronization algorithm used, the harder the real-time guarantees that can be given by the system. Numerous clock synchronization algoritms for wired networks have been proposed, which provide varying degrees of precision. Wireless networks provide a number of challenges which clock synchronization algorithms for wired networks do not address satisf...

  9. GALILEO Precise Orbit and Clock Determinaiton using GPS and GALILEO Combined Processing Strategy

    Science.gov (United States)

    Cui, Hongzheng; Tang, Geshi; Song, Baiyan; Liu, Huicui; Han, Chao; Ge, Maorong

    2014-05-01

    The GALILEO system-still in its development phase-will be Europe's GNSS, and the in-orbit validation (IOV) phase has begun with launch of two IOV satellites, IOV-1 (E11) and IOV-2 (E12). High precise data processing is the precondition for upgrading navigation precision, monitoring and assessment of GNSS Open services, and expanding the application region for satellite navigation system. BACC is doing the work about operation and maintenance the iGMAS (international GNSS Monitoring and Assessment Service) Analysis Center (BAC), and producing the precision products to the users with equivalent accuracy to well-known institutes, such as IGS and CODE including precise satellite orbit and clock, tracking station coordinate and receiver clock, Zenith Total Delay (ZTD), Earth Orientation Parameter (EOP) parameters, global and statistical integrity and Ionospheric map, and this study just focuses on the combined orbit and clock. For GALILEO in the initial deployment phase, in order to take advantage of GPS observation and mature models to do joint orbit determination in a unified time and space frame to improve the orbit of other systems, and use the GPS orbit and clock from joint solution as the external check, we adopt combined orbit determination of GPS and GALILEO fixing firstly the coordinate of station, receiver clock and tropospheric parameters using GPS precise ephemeris and clock, and seting inter-system bias (ISB) between GPS and GALILEO as a parameter to be estimated. The observation data from a network of multi-GNSS capable receivers from the MGEX tracking network and a regional multi-GNSS network operated by China from day 321 to 334 in 2013, and the satellite force models and GFZ standard observation modeling except Yaw-control model are used in three day solution. For impact analysis, we compare the GPS orbit and clock to IGS final orbit and clock products to evaluate the accuracy, and the accuracy of GALILEO orbit and clock and can be validated by checking

  10. 47 CFR 80.865 - Radiotelephone station clock.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Radiotelephone station clock. 80.865 Section 80.865 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... W § 80.865 Radiotelephone station clock. A clock having a face of at least 12.7 cm (5 in.) in...

  11. A practical clock synchronization algorithm for UWB positioning systems

    NARCIS (Netherlands)

    Xie, Y.; Janssen, G.J.M.; van der Veen, A.J.; Dong, Min; Zheng, Thomas Fang

    2016-01-01

    A clock synchronization scheme is crucial for obtaining accuracy in time-based positioning systems. Existing clock synchronization schemes are mostly based on a simplified linear clock model, which unfortunately have a poor long-term synchronization accuracy. Assuming a two-way time transfer

  12. On synchronization of clocks in general space-times

    Directory of Open Access Journals (Sweden)

    M. R. H Khajehpour

    2005-09-01

    Full Text Available   Einstein and transport synchronizations of infinitesimally spaced and distant clocks are considered in a general Riemannian space-time. It is shown that infinitesimally spaced clocks can always be synchronized. In general one can not find observers for whom distant clock are Einstein synchronized but transport synchronized observers do always exit. Whenever both procedures are possible, they are equivalent.

  13. Tick Tock, a Vitamin C Clock.

    Science.gov (United States)

    Wright, Stephen W.

    2002-01-01

    Presents an activity that uses supermarket chemicals to perform a clock reaction in which the endpoint is signaled by an abrupt change in the appearance from colorless to blue-black. This activity can be used to explore reaction kinetics and the effect of reactant concentrations on the apparent rate of reaction. (DDR)

  14. Central and peripheral clocks in ontogeny

    Czech Academy of Sciences Publication Activity Database

    Sumová, Alena; Bendová, Zdeňka; Sládek, Martin; El-Hennamy, Rehab; Laurinová, Kristýna; Jindráková, Zuzana; Illnerová, Helena

    2006-01-01

    Roč. 273, č. S1 (2006), s. 6-6 ISSN 1742-464X. [FEBS Congress /31./. 24.06.2006-29.06.2006, Istanbul] Institutional research plan: CEZ:AV0Z50110509 Keywords : circadian clock * peripheral tissue * ontogeny Subject RIV: FH - Neurology

  15. The Clocks Are Ticking: No More Delays!

    DEFF Research Database (Denmark)

    Bahr, Patrick; Grathwohl, Hans Bugge; Møgelberg, Rasmus Ejlers

    2017-01-01

    these applications can be carried out and machine-checked. In this paper, we take a step towards this goal by devising a suitable reduction semantics. We present Clocked Type Theory, a new type theory for guarded recursion that is more suitable for reduction semantics than the existing ones. We prove confluence...

  16. Food at work around the clock

    DEFF Research Database (Denmark)

    Dahl Lassen, Anne; Beck, Anne Marie; Thorsen, Anne Vibeke

    This report brings together 12 invited presentations and outcomes of a workshop on food and meals for employees working irregular hours “around the clock”. The workshop, “Food at work around the clock – The Nordic Model”, was hosted by the National Food Institute at the Technical University...

  17. The mammalian retina as a clock

    Science.gov (United States)

    Tosini, Gianluca; Fukuhara, Chiaki

    2002-01-01

    Many physiological, cellular, and biochemical parameters in the retina of vertebrates show daily rhythms that, in many cases, also persist under constant conditions. This demonstrates that they are driven by a circadian pacemaker. The presence of an autonomous circadian clock in the retina of vertebrates was first demonstrated in Xenopus laevis and then, several years later, in mammals. In X. laevis and in chicken, the retinal circadian pacemaker has been localized in the photoreceptor layer, whereas in mammals, such information is not yet available. Recent advances in molecular techniques have led to the identification of a group of genes that are believed to constitute the molecular core of the circadian clock. These genes are expressed in the retina, although with a slightly different 24-h profile from that observed in the central circadian pacemaker. This result suggests that some difference (at the molecular level) may exist between the retinal clock and the clock located in the suprachiasmatic nuclei of hypothalamus. The present review will focus on the current knowledge of the retinal rhythmicity and the mechanisms responsible for its control.

  18. Brain clocks for morning and evening behaviour

    Indian Academy of Sciences (India)

    Unknown

    Different subgroups of cells that regu- late the morning and evening components of activity are ... tion of time from circadian pacemaker to target organs? At least two decades ago, a model of circadian clocks .... type behaviour (with robust morning and evening bouts of activity) by expressing UAS-per in the CRY+ cells.

  19. Clock Synchronization for Multihop Wireless Sensor Networks

    Science.gov (United States)

    Solis Robles, Roberto

    2009-01-01

    In wireless sensor networks, more so generally than in other types of distributed systems, clock synchronization is crucial since by having this service available, several applications such as media access protocols, object tracking, or data fusion, would improve their performance. In this dissertation, we propose a set of algorithms to achieve…

  20. Pittendrigh: The Darwinian Clock-Watcher

    Indian Academy of Sciences (India)

    cyanobacteria. The abysmal numbers of plant and protists in particular is a reminder that current chronobiology research is very animal-centered, primarily due to the pressure to use models that can be functionally linked to the analyses of human disease. Back in the 1960s when nothing was known about clock genes and ...

  1. The skeletal muscle circadian clock: current insights

    Directory of Open Access Journals (Sweden)

    Nakao R

    2017-11-01

    Full Text Available Reiko Nakao,1 Takeshi Nikawa,2 Katsutaka Oishi1,3,4 1Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST, Tsukuba, 2Department of Nutritional Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 3Department of Applied Biological Science, Graduate School of Science and Technology, Tokyo University of Science, Noda, 4Department of Computational and Medical Sciences, Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa, Japan Abstract: Skeletal muscle functions in locomotion, postural support, and energy metabolism. The loss of skeletal muscle mass and function leads to diseases such as sarcopenia and metabolic disorders. Inactivity (lack of exercise and an imbalanced diet (increased fat or decreased protein intake are thought to be involved in the prevalence of such pathologies. On the other hand, recent epidemiological studies of humans have suggested that circadian disruption caused by shift work, jet lag, and sleep disorders is associated with obesity and metabolic syndrome. Experimental studies of mice deficient in clock genes have also identified skeletal muscle defects, suggesting a molecular link between circadian clock machinery and skeletal muscle physiology. Furthermore, accumulating evidence about chronotherapy, including chronopharmacology, chrononutrition, and chronoexercise, has indicated that timing is important to optimize medical intervention for various diseases. The present review addresses current understanding of the functional roles of the molecular clock with respect to skeletal muscle and the potential of chronotherapy for diseases associated with skeletal muscle. Keywords: biological rhythm, metabolic syndrome, physical activity, neural signal, chronotherapy

  2. Analytic clock frequency selection for global DVFS

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus; Hurink, Johann L.; Holzenspies, P.K.F.; Kuper, Jan; Smit, Gerardus Johannes Maria

    2014-01-01

    Computers can reduce their power consumption by decreasing their speed using Dynamic Voltage and Frequency Scaling (DVFS). A form of DVFS for multicore processors is global DVFS, where the voltage and clock frequency is shared among all processor cores. Because global DVFS is efficient and cheap to

  3. Genetics and Neurobiology of Circadian Clocks in Mammals

    Science.gov (United States)

    Park, Junghea; Lee, Choogon; Takahashi, Joseph S.

    2013-01-01

    In animals circadian behavior can be analyzed as an integrated system - beginning with genes leading ultimately to behavioral outputs. In the last decade, the molecular mechanism of circadian clocks has been unraveled primarily by the use of phenotype-driven (forward) genetic analysis in a number of model systems. Circadian oscillations are generated by a set of genes forming a transcriptional autoregulatory feedback loop. In mammals, there is a “core” set of circadian genes that form the primary negative feedback loop of the clock mechanism (Clock/Npas2, Bmal1, Per1, Per2, Cry1, Cry2 and CK1ε). Another dozen candidate genes have been identified and play additional roles in the circadian gene network such as the feedback loop involving Rev-erbα. Despite this remarkable progress, it is clear that a significant number of genes that strongly influence and regulate circadian rhythms in mammals remain to be discovered and identified. As part of a large-scale N-ethyl-N-nitrosourea (ENU) mutagenesis screen using a wide range of nervous system and behavioral phenotypes, we have identified a number of new circadian mutants in mice. Here we describe a new short period circadian mutant, part-time (prtm), which is caused by a loss-of-function mutation in the Cryptochrome1 gene. We also describe a long period circadian mutant named Overtime (Ovtm). Positional cloning and genetic complementation reveal that Ovtm is encoded by the F-box protein FBXL3 a component of the SKP1-CUL1-F-box-protein (SCF) E3 ubiquitin ligase complex. The Ovtm mutation causes an isoleucine to threonine (I364T) substitution leading to a loss-of-function in FBXL3 which interacts specifically with the CRYPTOCHROME (CRY) proteins. In Ovtm mice, expression of the PERIOD proteins PER1 and PER2 is reduced; however, the CRY proteins CRY1 and CRY2 are unchanged. The loss of FBXL3 function leads to a stabilization of the CRY proteins, which in turn leads to a global transcriptional repression of the Per and

  4. Orthogonally referenced integrated ensemble for navigation and timing

    Science.gov (United States)

    Smith, Stephen Fulton; Moore, James Anthony

    2014-04-01

    An orthogonally referenced integrated ensemble for navigation and timing includes a dual-polyhedral oscillator array, including an outer sensing array of oscillators and an inner clock array of oscillators situated inside the outer sensing array. The outer sensing array includes a first pair of sensing oscillators situated along a first axis of the outer sensing array, a second pair of sensing oscillators situated along a second axis of the outer sensing array, and a third pair of sensing oscillators situated along a third axis of the outer sensing array. The inner clock array of oscillators includes a first pair of clock oscillators situated along a first axis of the inner clock array, a second pair of clock oscillators situated along a second axis of the inner clock array, and a third pair of clock oscillators situated along a third axis of the inner clock array.

  5. Clock measurements to improve the geopotential determination

    Science.gov (United States)

    Lion, Guillaume; Panet, Isabelle; Delva, Pacôme; Wolf, Peter; Bize, Sébastien; Guerlin, Christine

    2017-04-01

    Comparisons between optical clocks with an accuracy and stability approaching the 10-18 in term of relative frequency shift are opening new perspectives for the direct determination of geopotential at a centimeter-level accuracy in geoid height. However, so far detailed quantitative estimates of the possible improvement in geoid determination when adding such clock measurements to existing data are lacking. In this context, the present work aims at evaluating the contribution of this new kind of direct measurements in determining the geopotential at high spatial resolution (10 km). We consider the Massif Central area, marked by smooth, moderate altitude mountains and volcanic plateaus leading to variations of the gravitational field over a range of spatial scales. In such type of region, the scarcity of gravity data is an important limitation in deriving accurate high resolution geopotential models. We summarize our methodology to assess the contribution of clock data in the geopotential recovery, in combination with ground gravity measurements. We sample synthetic gravity and disturbing potential data from a spherical harmonics geopotential model, and a topography model, up to 10 km resolution; we also build a potential control grid. From the synthetic data, we estimate the disturbing potential by least-squares collocation. Finally, we assess the quality of the reconstructed potential by comparing it to that of the control grid. We show that adding only a few clock data reduces the reconstruction bias significantly and improves the standard deviation by a factor 3. We discuss the role of different parameters, such as the effect of the data coverage and data quality on these results, the trade-off between the measurement noise level and the number of data, and the optimization of the clock data network.

  6. Pineal clock gene oscillation is disturbed in Alzheimer's disease, due to functional disconnection from the "master clock".

    NARCIS (Netherlands)

    Wu, Y.-H.; Fischer, D.F.; Kalsbeek, A.; Garidou-Boof, M.-L.; Vliet, J. van der; Heijningen, C. van; Liu, R.-Y.; Zhou, J.-N.; Swaab, D.F.

    2006-01-01

    The suprachiasmatic nucleus (SCN) is the "master clock" of the mammalian brain. It coordinates the peripheral clocks in the body, including the pineal clock that receives SCN input via a multisynaptic noradrenergic pathway. Rhythmic pineal melatonin production is disrupted in Alzheimer's disease

  7. Pineal clock gene oscillation is disturbed in Alzheimer's disease, due to functional disconnection from the "master clock"

    NARCIS (Netherlands)

    Wu, Ying-Hui; Fischer, David F.; Kalsbeek, Andries; Garidou-Boof, Marie-Laure; van der Vliet, Jan; van Heijningen, Caroline; Liu, Rong-Yu; Zhou, Jiang-Ning; Swaab, Dick F.

    2006-01-01

    The suprachiasmatic nucleus (SCN) is the "master clock" of the mammalian brain. It coordinates the peripheral clocks in the body, including the pineal clock that receives SCN input via a multisynaptic noradrenergic pathway. Rhythmic pineal melatonin production is disrupted in Alzheimer's disease

  8. The Circadian Clock Gene BMAL1 Coordinates Intestinal RegenerationSummary

    Directory of Open Access Journals (Sweden)

    Kyle Stokes

    2017-07-01

    Full Text Available Background & Aims: The gastrointestinal syndrome is an illness of the intestine caused by high levels of radiation. It is characterized by extensive loss of epithelial tissue integrity, which initiates a regenerative response by intestinal stem and precursor cells. The intestine has 24-hour rhythms in many physiological functions that are believed to be outputs of the circadian clock: a molecular system that produces 24-hour rhythms in transcription/translation. Certain gastrointestinal illnesses are worsened when the circadian rhythms are disrupted, but the role of the circadian clock in gastrointestinal regeneration has not been studied. Methods: We tested the timing of regeneration in the mouse intestine during the gastrointestinal syndrome. The role of the circadian clock was tested genetically using the BMAL1 loss of function mouse mutant in vivo, and in vitro using intestinal organoid culture. Results: The proliferation of the intestinal epithelium follows a 24-hour rhythm during the gastrointestinal syndrome. The circadian clock runs in the intestinal epithelium during this pathologic state, and the loss of the core clock gene, BMAL1, disrupts both the circadian clock and rhythmic proliferation. Circadian activity in the intestine involves a rhythmic production of inflammatory cytokines and subsequent rhythmic activation of the JNK stress response pathway. Conclusions: Our results show that a circadian rhythm in inflammation and regeneration occurs during the gastrointestinal syndrome. The study and treatment of radiation-induced illnesses, and other gastrointestinal illnesses, should consider 24-hour timing in physiology and pathology. Keywords: Intestine, Circadian Rhythms, Gastrointestinal Syndrome, TNF, Intestinal Stem Cells

  9. Efficient high-rate satellite clock estimation for PPP ambiguity resolution using carrier-ranges.

    Science.gov (United States)

    Chen, Hua; Jiang, Weiping; Ge, Maorong; Wickert, Jens; Schuh, Harald

    2014-11-25

    In order to catch up the short-term clock variation of GNSS satellites, clock corrections must be estimated and updated at a high-rate for Precise Point Positioning (PPP). This estimation is already very time-consuming for the GPS constellation only as a great number of ambiguities need to be simultaneously estimated. However, on the one hand better estimates are expected by including more stations, and on the other hand satellites from different GNSS systems must be processed integratively for a reliable multi-GNSS positioning service. To alleviate the heavy computational burden, epoch-differenced observations are always employed where ambiguities are eliminated. As the epoch-differenced method can only derive temporal clock changes which have to be aligned to the absolute clocks but always in a rather complicated way, in this paper, an efficient method for high-rate clock estimation is proposed using the concept of "carrier-range" realized by means of PPP with integer ambiguity resolution. Processing procedures for both post- and real-time processing are developed, respectively. The experimental validation shows that the computation time could be reduced to about one sixth of that of the existing methods for post-processing and less than 1 s for processing a single epoch of a network with about 200 stations in real-time mode after all ambiguities are fixed. This confirms that the proposed processing strategy will enable the high-rate clock estimation for future multi-GNSS networks in post-processing and possibly also in real-time mode.

  10. Untimely oxidative stress in β-cells leads to diabetes - Role of circadian clock in β-cell function.

    Science.gov (United States)

    Lee, J; Ma, K; Moulik, M; Yechoor, V

    2018-02-16

    Diabetes results from a loss of β-cell function. With the number of people with diabetes reaching epidemic proportions globally, understanding mechanisms that are contributing to this increasing prevalence is critical. One such factor has been circadian disruption, with shift-work, light pollution, jet-lag, increased screen time, all acting as potential contributory factors. Though circadian disruption has been epidemiologically associated with diabetes and other metabolic disorders for many decades, it is only recently that there has been a better understanding of the underlying molecular mechanisms. Experimental circadian disruption, via manipulation of environmental or genetic factors using gene-deletion mouse models, has demonstrated the importance of circadian rhythms in whole body metabolism. Genetic disruption of core clock genes, specifically in the β-cells in mice, have, now demonstrated the importance of the intrinsic β-cell clock in regulating function. Recent work has also shown the interaction of the circadian clock and enhancers in β-cells, indicating a highly integrated regulation of transcription and cellular function by the circadian clock. Disruption of either the whole body or only the β-cell clock leads to significant impairment of mitochondrial function, uncoupling, impaired vesicular transport, oxidative stress in β-cells and finally impaired glucose-stimulated insulin secretion and diabetes. In this review, we explore the role of the circadian clock in mitigating oxidative stress and preserving β-cell function. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Advancing Navigation, Timing, and Science with the Deep Space Atomic Clock

    Science.gov (United States)

    Ely, Todd A.; Seubert, Jill; Bell, Julia

    2014-01-01

    NASA's Deep Space Atomic Clock mission is developing a small, highly stable mercury ion atomic clock with an Allan deviation of at most 1e-14 at one day, and with current estimates near 3e-15. This stability enables one-way radiometric tracking data with accuracy equivalent to and, in certain conditions, better than current two-way deep space tracking data; allowing a shift to a more efficient and flexible one-way deep space navigation architecture. DSAC-enabled one-way tracking will benefit navigation and radio science by increasing the quantity and quality of tracking data. Additionally, DSAC would be a key component to fully-autonomous onboard radio navigation useful for time-sensitive situations. Potential deep space applications of DSAC are presented, including orbit determination of a Mars orbiter and gravity science on a Europa flyby mission.

  12. Timing Embryo Segmentation: Dynamics and Regulatory Mechanisms of the Vertebrate Segmentation Clock

    Directory of Open Access Journals (Sweden)

    Tatiana P. Resende

    2014-01-01

    Full Text Available All vertebrate species present a segmented body, easily observed in the vertebrate column and its associated components, which provides a high degree of motility to the adult body and efficient protection of the internal organs. The sequential formation of the segmented precursors of the vertebral column during embryonic development, the somites, is governed by an oscillating genetic network, the somitogenesis molecular clock. Herein, we provide an overview of the molecular clock operating during somite formation and its underlying molecular regulatory mechanisms. Human congenital vertebral malformations have been associated with perturbations in these oscillatory mechanisms. Thus, a better comprehension of the molecular mechanisms regulating somite formation is required in order to fully understand the origin of human skeletal malformations.

  13. Metabolism and the Circadian Clock Converge

    Science.gov (United States)

    Eckel-Mahan, Kristin

    2013-01-01

    Circadian rhythms occur in almost all species and control vital aspects of our physiology, from sleeping and waking to neurotransmitter secretion and cellular metabolism. Epidemiological studies from recent decades have supported a unique role for circadian rhythm in metabolism. As evidenced by individuals working night or rotating shifts, but also by rodent models of circadian arrhythmia, disruption of the circadian cycle is strongly associated with metabolic imbalance. Some genetically engineered mouse models of circadian rhythmicity are obese and show hallmark signs of the metabolic syndrome. Whether these phenotypes are due to the loss of distinct circadian clock genes within a specific tissue versus the disruption of rhythmic physiological activities (such as eating and sleeping) remains a cynosure within the fields of chronobiology and metabolism. Becoming more apparent is that from metabolites to transcription factors, the circadian clock interfaces with metabolism in numerous ways that are essential for maintaining metabolic homeostasis. PMID:23303907

  14. Supporting Family Awareness with the Whereabouts Clock

    Science.gov (United States)

    Sellen, Abigail; Taylor, Alex S.; Kaye, Joseph ‘Jofish'; Brown, Barry; Izadi, Shahram

    We report the results of a field trial of a situated awareness device for families called the “Whereabouts Clock”. The Clock displays the location of family members using cellphone data as one of four privacy-preserving, deliberately coarse-grained categories ( HOME, WORK, SCHOOL or ELSEWHERE). The results show that awareness of others through the Clock supports not only family communication and coordination but also more emotive aspects of family life such as reassurance, connectedness, identity and social touch. We discuss how the term “awareness” means many things in practice and highlight the importance of designing not just for family activities, but in order to support the emotional, social and even moral aspects of family life.

  15. The Large Built Water Clock Of Amphiaraeion.

    Science.gov (United States)

    Theodossiou, E.; Katsiotis, M.; Manimanis, V. N.; Mantarakis, P.

    A very well preserved ancient water clock was discovered during excavations at the Amphiaraeion, in Oropos, Greece. The Amphiaraeion, a famous religious and oracle center of the deified healer Amphiaraus, was active from the pre-classic period until the replacement of the ancient religion by Christianity in the 5th Century A.D.. The foretelling was supposedly done through dreams sent by the god to the believers sleeping in a special gallery. In these dreams the god suggesting to them the therapy for their illness or the solution to their problems. The patients, then threw coins into a spring of the sanctuary. In such a place, the measurement of time was a necessity. Therefore, time was kept with both a conical sundial and a water clock in the form of a fountain. According to archeologists, the large built structure that measured the time for the sanctuary dates from the 4th Century B.C.

  16. Circadian molecular clocks tick along ontogenesis

    Czech Academy of Sciences Publication Activity Database

    Sumová, Alena; Bendová, Zdeňka; Sládek, Martin; El-Hennamy, Rehab; Matějů, Kristýna; Polidarová, Lenka; Sosniyenko, Serhiy; Illnerová, Helena

    2008-01-01

    Roč. 57, Suppl.3 (2008), S139-S148 ISSN 0862-8408 R&D Projects: GA ČR GA309/08/0503; GA AV ČR(CZ) IAA500110605; GA MŠk(CZ) LC554 Grant - others:EC(XE) LSH-2004-115-4-018741 Institutional research plan: CEZ:AV0Z50110509 Keywords : circadian clock * ontogenesis * suprachiasmatic nucleus Subject RIV: FH - Neurology Impact factor: 1.653, year: 2008

  17. Effects of mass defect in atomic clocks

    Science.gov (United States)

    Taichenachev, A. V.; Yudin, V. I.

    2018-01-01

    We consider some implications of the mass defect on the frequency of atomic transitions. We have found that some well-known frequency shifts (such as gravitational and quadratic Doppler shifts) can be interpreted as consequences of the mass defect, i.e., without the need for the concept of time dilation used in special and general relativity theories. Moreover, we show that the inclusion of the mass defect leads to previously unknown shifts for clocks based on trapped ions..

  18. The circadian clock, reward and memory

    Directory of Open Access Journals (Sweden)

    Urs eAlbrecht

    2011-11-01

    Full Text Available During our daily activities, we experience variations in our cognitive performance, which is often accompanied by cravings for small rewards, such as consuming coffee or chocolate. This indicates that the time of day, cognitive performance and reward may be related to one another. This review will summarize data that describes the influence of the circadian clock on addiction and mood-related behavior and put the data into perspective in relation to memory processes.

  19. Molecular clock in neutral protein evolution

    Directory of Open Access Journals (Sweden)

    Wilke Claus O

    2004-08-01

    Full Text Available Abstract Background A frequent observation in molecular evolution is that amino-acid substitution rates show an index of dispersion (that is, ratio of variance to mean substantially larger than one. This observation has been termed the overdispersed molecular clock. On the basis of in silico protein-evolution experiments, Bastolla and coworkers recently proposed an explanation for this observation: Proteins drift in neutral space, and can temporarily get trapped in regions of substantially reduced neutrality. In these regions, substitution rates are suppressed, which results in an overall substitution process that is not Poissonian. However, the simulation method of Bastolla et al. is representative only for cases in which the product of mutation rate μ and population size Ne is small. How the substitution process behaves when μNe is large is not known. Results Here, I study the behavior of the molecular clock in in silico protein evolution as a function of mutation rate and population size. I find that the index of dispersion decays with increasing μNe, and approaches 1 for large μNe . This observation can be explained with the selective pressure for mutational robustness, which is effective when μNe is large. This pressure keeps the population out of low-neutrality traps, and thus steadies the ticking of the molecular clock. Conclusions The molecular clock in neutral protein evolution can fall into two distinct regimes, a strongly overdispersed one for small μNe, and a mostly Poissonian one for large μNe. The former is relevant for the majority of organisms in the plant and animal kingdom, and the latter may be relevant for RNA viruses.

  20. Pneumatic oscillator circuits for timing and control of integrated microfluidics.

    Science.gov (United States)

    Duncan, Philip N; Nguyen, Transon V; Hui, Elliot E

    2013-11-05

    Frequency references are fundamental to most digital systems, providing the basis for process synchronization, timing of outputs, and waveform synthesis. Recently, there has been growing interest in digital logic systems that are constructed out of microfluidics rather than electronics, as a possible means toward fully integrated laboratory-on-a-chip systems that do not require any external control apparatus. However, the full realization of this goal has not been possible due to the lack of on-chip frequency references, thus requiring timing signals to be provided from off-chip. Although microfluidic oscillators have been demonstrated, there have been no reported efforts to characterize, model, or optimize timing accuracy, which is the fundamental metric of a clock. Here, we report pneumatic ring oscillator circuits built from microfluidic valves and channels. Further, we present a compressible-flow analysis that differs fundamentally from conventional circuit theory, and we show the utility of this physically based model for the optimization of oscillator stability. Finally, we leverage microfluidic clocks to demonstrate circuits for the generation of phase-shifted waveforms, self-driving peristaltic pumps, and frequency division. Thus, pneumatic oscillators can serve as on-chip frequency references for microfluidic digital logic circuits. On-chip clocks and pumps both constitute critical building blocks on the path toward achieving autonomous laboratory-on-a-chip devices.

  1. Early evolution of the land plant circadian clock.

    Science.gov (United States)

    Linde, Anna-Malin; Eklund, D Magnus; Kubota, Akane; Pederson, Eric R A; Holm, Karl; Gyllenstrand, Niclas; Nishihama, Ryuichi; Cronberg, Nils; Muranaka, Tomoaki; Oyama, Tokitaka; Kohchi, Takayuki; Lagercrantz, Ulf

    2017-10-01

    While angiosperm clocks can be described as an intricate network of interlocked transcriptional feedback loops, clocks of green algae have been modelled as a loop of only two genes. To investigate the transition from a simple clock in algae to a complex one in angiosperms, we performed an inventory of circadian clock genes in bryophytes and charophytes. Additionally, we performed functional characterization of putative core clock genes in the liverwort Marchantia polymorpha and the hornwort Anthoceros agrestis. Phylogenetic construction was combined with studies of spatiotemporal expression patterns and analysis of M. polymorpha clock gene mutants. Homologues to core clock genes identified in Arabidopsis were found not only in bryophytes but also in charophytes, albeit in fewer copies. Circadian rhythms were detected for most identified genes in M. polymorpha and A. agrestis, and mutant analysis supports a role for putative clock genes in M. polymorpha. Our data are in line with a recent hypothesis that adaptation to terrestrial life occurred earlier than previously expected in the evolutionary history of charophyte algae. Both gene duplication and acquisition of new genes was important in the evolution of the plant circadian clock, but gene loss has also contributed to shaping the clock of bryophytes. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  2. The hepatic circadian clock modulates xenobiotic metabolism in mice.

    Science.gov (United States)

    DeBruyne, Jason P; Weaver, David R; Dallmann, Robert

    2014-08-01

    The circadian clock generates daily cycles of gene expression that regulate physiological processes. The liver plays an important role in xenobiotic metabolism and also has been shown to possess its own cell-based clock. The liver clock is synchronized by the master clock in the brain, and a portion of rhythmic gene expression can be driven by behavior of the organism as a whole even when the hepatic clock is suppressed. So far, however, there is relatively little evidence indicating whether the liver clock is functionally important in modulating xenobiotic metabolism. Thus, mice lacking circadian clock function in the whole body or specifically in liver were challenged with pentobarbital and acetaminophen, and pentobarbital sleep time (PBST) and acetaminophen toxicity, respectively, was assessed at different times of day in mutant and control mice. The results suggest that the liver clock is essential for rhythmic changes in xenobiotic detoxification. Surprisingly, it seems that the way in which the clock is disrupted determines the rate of xenobiotic metabolism in the liver. CLOCK-deficient mice are remarkably resistant to acetaminophen and exhibit a longer PBST, while PERIOD-deficient mice have a short PBST. These results indicate an essential role of the tissue-intrinsic peripheral circadian oscillator in the liver in regulating xenobiotic metabolism. © 2014 The Author(s).

  3. Dynamical mechanism of Bmal 1 / Rev- erbα loop in circadian clock

    Science.gov (United States)

    Li, Ying; Liu, Zengrong

    2015-07-01

    In mammals, the circadian clock is driven by multiple integrated transcriptional feedback loops involving three kinds of central clock-controlled elements (CCEs): E-boxes, D-boxes and ROR-elements. With the aid of CCEs, the concentrations of the active proteins are approximated by the delayed concentrations of mRNAs, which simplifies the circadian system drastically. The regulatory loop composed by BMAL1 and REV-ERB- α plays important roles in circadian clock. With delay differential equations, we gave a mathematical model of this loop and investigated its dynamical mechanisms. Specially, we theoretically provided the sufficient conditions for sustained oscillation of the loop with Hopf bifurcation theory. The total of delays determines the emergence of oscillators, which explains the crucial roles of delays in circadian clock revealed by biological experiments. Numerically, we studied the amplitude and period against the variations of delays and the degradation rates. The different sensitivities of amplitude and period on these factors provide ideas to adjust the amplitude or period of circadian oscillators.

  4. Microfabricated vapor cells filled with a cesium dispensing paste for miniature atomic clocks

    Science.gov (United States)

    Maurice, V.; Rutkowski, J.; Kroemer, E.; Bargiel, S.; Passilly, N.; Boudot, R.; Gorecki, C.; Mauri, L.; Moraja, M.

    2017-04-01

    A method for filling alkali vapor cells with cesium from a dispensing paste is proposed and its compliance with miniature atomic clock applications is evaluated. The paste is an organic-inorganic composition of cesium molybdate, zirconium-aluminum powder, and a hybrid organic-inorganic binder. It is compatible with collective deposition processes such as micro-drop dispensing, which can be done under ambient atmosphere at the wafer-level. After deposition and sealing by anodic bonding, cesium is released from the consolidated paste through local heating with a high power laser. Linear absorption signals have been observed over one year in several cells, showing a stable atomic density. For further validation of this technology for clock applications, one cell has been implemented in a coherent population trapping clock setup to monitor its frequency stability. A fractional frequency aging rate around -4.4 × 10-12 per day has been observed, which is compliant with a clock frequency instability below 1 × 10-11 at one day integration time. This filling method can drastically reduce the cost and the complexity of alkali vapor cell fabrication.

  5. Interplay between Dioxin-Mediated Signaling and Circadian Clock: A Possible Determinant in Metabolic Homeostasis

    Directory of Open Access Journals (Sweden)

    Chun Wang

    2014-07-01

    Full Text Available The rotation of the earth on its axis creates the environment of a 24 h solar day, which organisms on earth have used to their evolutionary advantage by integrating this timing information into their genetic make-up in the form of a circadian clock. This intrinsic molecular clock is pivotal for maintenance of synchronized homeostasis between the individual organism and the external environment to allow coordinated rhythmic physiological and behavioral function. Aryl hydrocarbon receptor (AhR is a master regulator of dioxin-mediated toxic effects, and is, therefore, critical in maintaining adaptive responses through regulating the expression of phase I/II drug metabolism enzymes. AhR expression is robustly rhythmic, and physiological cross-talk between AhR signaling and circadian rhythms has been established. Increasing evidence raises a compelling argument that disruption of endogenous circadian rhythms contributes to the development of disease, including sleep disorders, metabolic disorders and cancers. Similarly, exposure to environmental pollutants through air, water and food, is increasingly cited as contributory to these same problems. Thus, a better understanding of interactions between AhR signaling and the circadian clock regulatory network can provide critical new insights into environmentally regulated disease processes. This review highlights recent advances in the understanding of the reciprocal interactions between dioxin-mediated AhR signaling and the circadian clock including how these pathways relate to health and disease, with emphasis on the control of metabolic function.

  6. Timing avian long-distance migration: from internal clock mechanisms to global flights.

    Science.gov (United States)

    Åkesson, Susanne; Ilieva, Mihaela; Karagicheva, Julia; Rakhimberdiev, Eldar; Tomotani, Barbara; Helm, Barbara

    2017-11-19

    Migratory birds regularly perform impressive long-distance flights, which are timed relative to the anticipated environmental resources at destination areas that can be several thousand kilometres away. Timely migration requires diverse strategies and adaptations that involve an intricate interplay between internal clock mechanisms and environmental conditions across the annual cycle. Here we review what challenges birds face during long migrations to keep track of time as they exploit geographically distant resources that may vary in availability and predictability, and summarize the clock mechanisms that enable them to succeed. We examine the following challenges: departing in time for spring and autumn migration, in anticipation of future environmental conditions; using clocks on the move, for example for orientation, navigation and stopover; strategies of adhering to, or adjusting, the time programme while fitting their activities into an annual cycle; and keeping pace with a world of rapidly changing environments. We then elaborate these themes by case studies representing long-distance migrating birds with different annual movement patterns and associated adaptations of their circannual programmes. We discuss the current knowledge on how endogenous migration programmes interact with external information across the annual cycle, how components of annual cycle programmes encode topography and range expansions, and how fitness may be affected when mismatches between timing and environmental conditions occur. Lastly, we outline open questions and propose future research directions.This article is part of the themed issue 'Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'. © 2017 The Author(s).

  7. Histone lysine demethylase JARID1a activates CLOCK-BMAL1 and influences the circadian clock.

    Science.gov (United States)

    DiTacchio, Luciano; Le, Hiep D; Vollmers, Christopher; Hatori, Megumi; Witcher, Michael; Secombe, Julie; Panda, Satchidananda

    2011-09-30

    In animals, circadian oscillators are based on a transcription-translation circuit that revolves around the transcription factors CLOCK and BMAL1. We found that the JumonjiC (JmjC) and ARID domain-containing histone lysine demethylase 1a (JARID1a) formed a complex with CLOCK-BMAL1, which was recruited to the Per2 promoter. JARID1a increased histone acetylation by inhibiting histone deacetylase 1 function and enhanced transcription by CLOCK-BMAL1 in a demethylase-independent manner. Depletion of JARID1a in mammalian cells reduced Per promoter histone acetylation, dampened expression of canonical circadian genes, and shortened the period of circadian rhythms. Drosophila lines with reduced expression of the Jarid1a homolog, lid, had lowered Per expression and similarly altered circadian rhythms. JARID1a thus has a nonredundant role in circadian oscillator function.

  8. Physics of fully ionized regions

    International Nuclear Information System (INIS)

    Flower, D.

    1975-01-01

    In this paper the term fully ionised regions is taken to embrace both planetary nebulae and the so-called 'H II' regions referred to as H + regions. Whilst these two types of gaseous nebulae are very different from an evolutionary standpoint, they are physically very similar, being characterised by photoionisation of a low-density plasma by a hot star. (Auth.)

  9. Synthetic Spin-Orbit Coupling in an Optical Lattice Clock

    Science.gov (United States)

    Wall, Michael L.; Koller, Andrew P.; Li, Shuming; Zhang, Xibo; Cooper, Nigel R.; Ye, Jun; Rey, Ana Maria

    2016-01-01

    We propose the use of optical lattice clocks operated with fermionic alkaline-earth atoms to study spin-orbit coupling (SOC) in interacting many-body systems. The SOC emerges naturally during the clock interrogation, when atoms are allowed to tunnel and accumulate a phase set by the ratio of the "magic" lattice wavelength to the clock transition wavelength. We demonstrate how standard protocols such as Rabi and Ramsey spectroscopy that take advantage of the sub-Hertz resolution of state-of-the-art clock lasers can perform momentum-resolved band tomography and determine SOC-induced s -wave collisions in nuclear-spin-polarized fermions. With the use of a second counterpropagating clock beam, we propose a method for engineering controlled atomic transport and study how it is modified by p - and s -wave interactions. The proposed spectroscopic probes provide clean and well-resolved signatures at current clock operating temperatures.

  10. The Effects of Clock Drift on the Mars Exploration Rovers

    Science.gov (United States)

    Ali, Khaled S.; Vanelli, C. Anthony

    2012-01-01

    All clocks drift by some amount, and the mission clock on the Mars Exploration Rovers (MER) is no exception. The mission clock on both MER rovers drifted significantly since the rovers were launched, and it is still drifting on the Opportunity rover. The drift rate is temperature dependent. Clock drift causes problems for onboard behaviors and spacecraft operations, such as attitude estimation, driving, operation of the robotic arm, pointing for imaging, power analysis, and telecom analysis. The MER operations team has techniques to deal with some of these problems. There are a few techniques for reducing and eliminating the clock drift, but each has drawbacks. This paper presents an explanation of what is meant by clock drift on the rovers, its relationship to temperature, how we measure it, what problems it causes, how we deal with those problems, and techniques for reducing the drift.

  11. Fully implicit kinetic modelling of collisional plasmas

    International Nuclear Information System (INIS)

    Mousseau, V.A.

    1996-05-01

    This dissertation describes a numerical technique, Matrix-Free Newton Krylov, for solving a simplified Vlasov-Fokker-Planck equation. This method is both deterministic and fully implicit, and may not have been a viable option before current developments in numerical methods. Results are presented that indicate the efficiency of the Matrix-Free Newton Krylov method for these fully-coupled, nonlinear integro-differential equations. The use and requirement for advanced differencing is also shown. To this end, implementations of Chang-Cooper differencing and flux limited Quadratic Upstream Interpolation for Convective Kinematics (QUICK) are presented. Results are given for a fully kinetic ion-electron problem with a self consistent electric field calculated from the ion and electron distribution functions. This numerical method, including advanced differencing, provides accurate solutions, which quickly converge on workstation class machines. It is demonstrated that efficient steady-state solutions can be achieved to the non-linear integro-differential equation, obtaining quadratic convergence, without incurring the large memory requirements of an integral operator. Model problems are presented which simulate plasma impinging on a plate with both high and low neutral particle recycling typical of a divertor in a Tokamak device. These model problems demonstrate the performance of the new solution method

  12. FAD regulates CRYPTOCHROME protein stability and circadian clock in mice

    OpenAIRE

    Hirano, Arisa; Braas, Daniel; Fu, Ying-Hui; Ptáček, Louis J.

    2017-01-01

    The circadian clock generates biological rhythms of metabolic and physiological processes, including the sleep-wake cycle. We previously identified a missense mutation in the flavin adenine dinucleotide (FAD) binding pocket of CRYPTOCHROME2 (CRY2), a clock protein that causes human advanced sleep phase. This prompted us to examine the role of FAD as a mediator of the clock and metabolism. FAD stabilized CRY proteins, leading to increased protein levels. In contrast, knockdown of Riboflavin ki...

  13. Relativity theory and time perception: single or multiple clocks?

    Science.gov (United States)

    Buhusi, Catalin V; Meck, Warren H

    2009-07-22

    Current theories of interval timing assume that humans and other animals time as if using a single, absolute stopwatch that can be stopped or reset on command. Here we evaluate the alternative view that psychological time is represented by multiple clocks, and that these clocks create separate temporal contexts by which duration is judged in a relative manner. Two predictions of the multiple-clock hypothesis were tested. First, that the multiple clocks can be manipulated (stopped and/or reset) independently. Second, that an event of a given physical duration would be perceived as having different durations in different temporal contexts, i.e., would be judged differently by each clock. Rats were trained to time three durations (e.g., 10, 30, and 90 s). When timing was interrupted by an unexpected gap in the signal, rats reset the clock used to time the "short" duration, stopped the "medium" duration clock, and continued to run the "long" duration clock. When the duration of the gap was manipulated, the rats reset these clocks in a hierarchical order, first the "short", then the "medium", and finally the "long" clock. Quantitative modeling assuming re-allocation of cognitive resources in proportion to the relative duration of the gap to the multiple, simultaneously timed event durations was used to account for the results. These results indicate that the three event durations were effectively timed by separate clocks operated independently, and that the same gap duration was judged relative to these three temporal contexts. Results suggest that the brain processes the duration of an event in a manner similar to Einstein's special relativity theory: A given time interval is registered differently by independent clocks dependent upon the context.

  14. Relativity theory and time perception: single or multiple clocks?

    Directory of Open Access Journals (Sweden)

    Catalin V Buhusi

    2009-07-01

    Full Text Available Current theories of interval timing assume that humans and other animals time as if using a single, absolute stopwatch that can be stopped or reset on command. Here we evaluate the alternative view that psychological time is represented by multiple clocks, and that these clocks create separate temporal contexts by which duration is judged in a relative manner. Two predictions of the multiple-clock hypothesis were tested. First, that the multiple clocks can be manipulated (stopped and/or reset independently. Second, that an event of a given physical duration would be perceived as having different durations in different temporal contexts, i.e., would be judged differently by each clock.Rats were trained to time three durations (e.g., 10, 30, and 90 s. When timing was interrupted by an unexpected gap in the signal, rats reset the clock used to time the "short" duration, stopped the "medium" duration clock, and continued to run the "long" duration clock. When the duration of the gap was manipulated, the rats reset these clocks in a hierarchical order, first the "short", then the "medium", and finally the "long" clock. Quantitative modeling assuming re-allocation of cognitive resources in proportion to the relative duration of the gap to the multiple, simultaneously timed event durations was used to account for the results.These results indicate that the three event durations were effectively timed by separate clocks operated independently, and that the same gap duration was judged relative to these three temporal contexts. Results suggest that the brain processes the duration of an event in a manner similar to Einstein's special relativity theory: A given time interval is registered differently by independent clocks dependent upon the context.

  15. System-wide power management control via clock distribution network

    Science.gov (United States)

    Coteus, Paul W.; Gara, Alan; Gooding, Thomas M.; Haring, Rudolf A.; Kopcsay, Gerard V.; Liebsch, Thomas A.; Reed, Don D.

    2015-05-19

    An apparatus, method and computer program product for automatically controlling power dissipation of a parallel computing system that includes a plurality of processors. A computing device issues a command to the parallel computing system. A clock pulse-width modulator encodes the command in a system clock signal to be distributed to the plurality of processors. The plurality of processors in the parallel computing system receive the system clock signal including the encoded command, and adjusts power dissipation according to the encoded command.

  16. Synthesizing genetic sequential logic circuit with clock pulse generator

    OpenAIRE

    Chuang, Chia-Hua; Lin, Chun-Liang

    2014-01-01

    Background Rhythmic clock widely occurs in biological systems which controls several aspects of cell physiology. For the different cell types, it is supplied with various rhythmic frequencies. How to synthesize a specific clock signal is a preliminary but a necessary step to further development of a biological computer in the future. Results This paper presents a genetic sequential logic circuit with a clock pulse generator based on a synthesized genetic oscillator, which generates a consecut...

  17. A Sizing Algorithm for Non-Overlapping Clock Signal Generators

    OpenAIRE

    Kavak, Fatih

    2004-01-01

    The non-overlapping clock signal generator circuits are key elements in switched capacitor circuits since non-overlapping clock signals are generally required. Non-overlapping clock signals means signals running at the same frequency and there is a time between the pulses that none of them is high. This time (when both pulses are logic 0) takes place when the pulses are switching from logic 1 to logic 0 or from logic 0 to logic 1. In this thesis this type of clock signal generators are analyz...

  18. Synthesizing genetic sequential logic circuit with clock pulse generator.

    Science.gov (United States)

    Chuang, Chia-Hua; Lin, Chun-Liang

    2014-05-28

    Rhythmic clock widely occurs in biological systems which controls several aspects of cell physiology. For the different cell types, it is supplied with various rhythmic frequencies. How to synthesize a specific clock signal is a preliminary but a necessary step to further development of a biological computer in the future. This paper presents a genetic sequential logic circuit with a clock pulse generator based on a synthesized genetic oscillator, which generates a consecutive clock signal whose frequency is an inverse integer multiple to that of the genetic oscillator. An analogous electronic waveform-shaping circuit is constructed by a series of genetic buffers to shape logic high/low levels of an oscillation input in a basic sinusoidal cycle and generate a pulse-width-modulated (PWM) output with various duty cycles. By controlling the threshold level of the genetic buffer, a genetic clock pulse signal with its frequency consistent to the genetic oscillator is synthesized. A synchronous genetic counter circuit based on the topology of the digital sequential logic circuit is triggered by the clock pulse to synthesize the clock signal with an inverse multiple frequency to the genetic oscillator. The function acts like a frequency divider in electronic circuits which plays a key role in the sequential logic circuit with specific operational frequency. A cascaded genetic logic circuit generating clock pulse signals is proposed. Based on analogous implement of digital sequential logic circuits, genetic sequential logic circuits can be constructed by the proposed approach to generate various clock signals from an oscillation signal.

  19. Diamond Electron-Spin Clocks For Space Navigation and Communication

    Data.gov (United States)

    National Aeronautics and Space Administration — Precision clocks are needed in a broad range of applications, including satellite communication, high-bandwidth wireless communication, computing systems, and...

  20. Improvement of an Atomic Clock using Squeezed Vacuum

    DEFF Research Database (Denmark)

    Kruse, I.; Lange, K; Peise, Jan

    2016-01-01

    , the vacuum noise restricts the precision of the interferometer to the standard quantum limit (SQL). Here, we propose and experimentally demonstrate a novel clock configuration that surpasses the SQL by squeezing the vacuum in the empty input state. We create a squeezed vacuum state containing an average of 0.......75 atoms to improve the clock sensitivity of 10000 atoms by 2.05+0.34−0.37  dB. The SQL poses a significant limitation for today’s microwave fountain clocks, which serve as the main time reference. We evaluate the major technical limitations and challenges for devising a next generation of fountain clocks...

  1. Clock Genes: Critical Modulators of Breast Cancer Risk

    National Research Council Canada - National Science Library

    Kennaway, David J; Butler, Lisa M; Tilley, Wayne D

    2005-01-01

    .... Circadian rhythms are regulated by a panel of specific transcription factors, called clock genes, and our current understanding of endogenous cellular rhythmicity is that both positive and negative...

  2. Creating a Collaborative "Hot Clock": Using Smart Phones to Motivate Students' Learning in News Interviewing and Reporting

    Science.gov (United States)

    Wei, Fang-Yi Flora

    2016-01-01

    This unit activity is integrated into the chapters on radio of the appropriate course--Survey of Mass Media, Broadcast Journalism, News Writing, Media Programing, or Communication Technology. Employing the concept of a "hot-clock radio format," the purpose of this unit activity is to motivate students' collaborative learning in news…

  3. Fully Passive Wireless Acquisition of Neuropotentials

    Science.gov (United States)

    Schwerdt, Helen N.

    The ability to monitor electrophysiological signals from the sentient brain is requisite to decipher its enormously complex workings and initiate remedial solutions for the vast amount of neurologically-based disorders. Despite immense advancements in creating a variety of instruments to record signals from the brain, the translation of such neurorecording instrumentation to real clinical domains places heavy demands on their safety and reliability, both of which are not entirely portrayed by presently existing implantable recording solutions. In an attempt to lower these barriers, alternative wireless radar backscattering techniques are proposed to render the technical burdens of the implant chip to entirely passive neurorecording processes that transpire in the absence of formal integrated power sources or powering schemes along with any active circuitry. These radar-like wireless backscattering mechanisms are used to conceive of fully passive neurorecording operations of an implantable microsystem. The fully passive device potentially manifests inherent advantages over current wireless implantable and wired recording systems: negligible heat dissipation to reduce risks of brain tissue damage and minimal circuitry for long term reliability as a chronic implant. Fully passive neurorecording operations are realized via intrinsic nonlinear mixing properties of the varactor diode. These mixing and recording operations are directly activated by wirelessly interrogating the fully passive device with a microwave carrier signal. This fundamental carrier signal, acquired by the implant antenna, mixes through the varactor diode along with the internal targeted neuropotential brain signals to produce higher frequency harmonics containing the targeted neuropotential signals. These harmonics are backscattered wirelessly to the external interrogator that retrieves and recovers the original neuropotential brain signal. The passive approach removes the need for internal power

  4. Assembly of a comprehensive regulatory network for the mammalian circadian clock: a bioinformatics approach.

    Directory of Open Access Journals (Sweden)

    Robert Lehmann

    Full Text Available By regulating the timing of cellular processes, the circadian clock provides a way to adapt physiology and behaviour to the geophysical time. In mammals, a light-entrainable master clock located in the suprachiasmatic nucleus (SCN controls peripheral clocks that are present in virtually every body cell. Defective circadian timing is associated with several pathologies such as cancer and metabolic and sleep disorders. To better understand the circadian regulation of cellular processes, we developed a bioinformatics pipeline encompassing the analysis of high-throughput data sets and the exploitation of published knowledge by text-mining. We identified 118 novel potential clock-regulated genes and integrated them into an existing high-quality circadian network, generating the to-date most comprehensive network of circadian regulated genes (NCRG. To validate particular elements in our network, we assessed publicly available ChIP-seq data for BMAL1, REV-ERBα/β and RORα/γ proteins and found strong evidence for circadian regulation of Elavl1, Nme1, Dhx6, Med1 and Rbbp7 all of which are involved in the regulation of tumourigenesis. Furthermore, we identified Ncl and Ddx6, as targets of RORγ and REV-ERBα, β, respectively. Most interestingly, these genes were also reported to be involved in miRNA regulation; in particular, NCL regulates several miRNAs, all involved in cancer aggressiveness. Thus, NCL represents a novel potential link via which the circadian clock, and specifically RORγ, regulates the expression of miRNAs, with particular consequences in breast cancer progression. Our findings bring us one step forward towards a mechanistic understanding of mammalian circadian regulation, and provide further evidence of the influence of circadian deregulation in cancer.

  5. Fully CMOS-compatible titanium nitride nanoantennas

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Justin A., E-mail: jabriggs@stanford.edu [Department of Applied Physics, Stanford University, 348 Via Pueblo Mall, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305 (United States); Naik, Gururaj V.; Baum, Brian K.; Dionne, Jennifer A. [Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305 (United States); Petach, Trevor A.; Goldhaber-Gordon, David [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305 (United States)

    2016-02-01

    CMOS-compatible fabrication of plasmonic materials and devices will accelerate the development of integrated nanophotonics for information processing applications. Using low-temperature plasma-enhanced atomic layer deposition (PEALD), we develop a recipe for fully CMOS-compatible titanium nitride (TiN) that is plasmonic in the visible and near infrared. Films are grown on silicon, silicon dioxide, and epitaxially on magnesium oxide substrates. By optimizing the plasma exposure per growth cycle during PEALD, carbon and oxygen contamination are reduced, lowering undesirable loss. We use electron beam lithography to pattern TiN nanopillars with varying diameters on silicon in large-area arrays. In the first reported single-particle measurements on plasmonic TiN, we demonstrate size-tunable darkfield scattering spectroscopy in the visible and near infrared regimes. The optical properties of this CMOS-compatible material, combined with its high melting temperature and mechanical durability, comprise a step towards fully CMOS-integrated nanophotonic information processing.

  6. An association between clock genes and clock-controlled cell cycle genes in murine colorectal tumors

    Czech Academy of Sciences Publication Activity Database

    Soták, Matúš; Polidarová, Lenka; Ergang, Peter; Sumová, Alena; Pácha, Jiří

    2013-01-01

    Roč. 132, č. 5 (2013), s. 1032-1041 ISSN 0020-7136 R&D Projects: GA MZd(CZ) NS9982 Institutional research plan: CEZ:AV0Z50110509 Keywords : cancer * circadian rhythm * peripheral circadian clock Subject RIV: FE - Other Internal Medicine Disciplines Impact factor: 5.007, year: 2013

  7. Code-Phase Clock Bias and Frequency Offset in PPP Clock Solutions.

    Science.gov (United States)

    Defraigne, Pascale; Sleewaegen, Jean-Marie

    2016-07-01

    Precise point positioning (PPP) is a zero-difference single-station technique that has proved to be very effective for time and frequency transfer, enabling the comparison of atomic clocks with a precision of a hundred picoseconds and a one-day stability below the 1e-15 level. It was, however, noted that for some receivers, a frequency difference is observed between the clock solution based on the code measurements and the clock solution based on the carrier-phase measurements. These observations reveal some inconsistency either between the code and carrier phases measured by the receiver or between the data analysis strategy of codes and carrier phases. One explanation for this discrepancy is the time offset that can exist for some receivers between the code and the carrier-phase latching. This paper explains how a code-phase bias in the receiver hardware can induce a frequency difference between the code and the carrier-phase clock solutions. The impact on PPP is then quantified. Finally, the possibility to determine this code-phase bias in the PPP modeling is investigated, and the first results are shown to be inappropriate due to the high level of code noise.

  8. Circadian expression of clock genes and clock-controlled genes in the rat retina

    NARCIS (Netherlands)

    Kamphuis, Willem; Cailotto, Cathy; Dijk, Frederike; Bergen, Arthur; Buijs, Ruud M.

    2005-01-01

    The circadian expression patterns of genes encoding for proteins that make up the core of the circadian clock were measured in rat retina using real-time quantitative PCR (qPCR). Transcript levels of several genes previously used for normalization of qPCR assays were determined and the effect of

  9. Comparisons of Synchronous-Clocking SFQ Adders

    Science.gov (United States)

    Takagi, Naofumi; Tanaka, Masamitsu

    Recent advances of superconducting single-flux-quantum (SFQ) circuit technology make it attractive to investigate computing systems using SFQ circuits, where arithmetic circuits play important roles. In order to develop excellent SFQ arithmetic circuits, we have to design or select their underlying algorithms, called hardware algorithms, from different point of view than CMOS circuits, because SFQ circuits work by pulse logic while CMOS circuits work by level logic. In this paper, we compare implementations of hardware algorithms for addition by synchronous-clocking SFQ circuits. We show that a set of individual bit-serial adders and Kogge-Stone adder are superior to others.

  10. Mass defect effects in atomic clocks

    Science.gov (United States)

    Yudin, Valeriy; Taichenachev, Alexey

    2018-03-01

    We consider some implications of the mass defect on the frequency of atomic transitions. We have found that some well-known frequency shifts (the gravitational shift and motion-induced shifts such as quadratic Doppler and micromotion shifts) can be interpreted as consequences of the mass defect in quantum atomic physics, i.e. without the need for the concept of time dilation used in special and general relativity theories. Moreover, we show that the inclusion of the mass defect leads to previously unknown shifts for clocks based on trapped ions.

  11. Laser Cooled Atomic Clocks in Space

    Science.gov (United States)

    Thompson, R. J.; Kohel, J.; Klipstein, W. M.; Seidel, D. J.; Maleki, L.

    2000-01-01

    The goals of the Glovebox Laser-cooled Atomic Clock Experiment (GLACE) are: (1) first utilization of tunable, frequency-stabilized lasers in space, (2) demonstrate laser cooling and trapping in microgravity, (3) demonstrate longest 'perturbation-free' interaction time for a precision measurement on neutral atoms, (4) Resolve Ramsey fringes 2-10 times narrower than achievable on Earth. The approach taken is: the use of COTS components, and the utilization of prototype hardware from LCAP flight definition experiments. The launch date is scheduled for Oct. 2002. The Microgravity Science Glovebox (MSG) specifications are reviewed, and a picture of the MSG is shown.

  12. Integration

    DEFF Research Database (Denmark)

    Emerek, Ruth

    2004-01-01

    Bidraget diskuterer de forskellige intergrationsopfattelse i Danmark - og hvad der kan forstås ved vellykket integration......Bidraget diskuterer de forskellige intergrationsopfattelse i Danmark - og hvad der kan forstås ved vellykket integration...

  13. Ultradian feeding in mice not only affects the peripheral clock in the liver, but also the master clock in the brain

    NARCIS (Netherlands)

    Sen, Satish; Raingard, Hélène; Dumont, Stéphanie; Kalsbeek, A.; Vuillez, Patrick; Challet, Etienne

    2017-01-01

    Restricted feeding during the resting period causes pronounced shifts in a number of peripheral clocks, but not the central clock in the suprachiasmatic nucleus (SCN). By contrast, daily caloric restriction impacts also the light-entrained SCN clock, as indicated by shifted oscillations of clock

  14. The Renaissance or the cuckoo clock.

    Science.gov (United States)

    Pines, Jonathon; Hagan, Iain

    2011-12-27

    '…in Italy, for thirty years under the Borgias, they had warfare, terror, murder and bloodshed, but they produced Michelangelo, Leonardo da Vinci and the Renaissance. In Switzerland, they had brotherly love, they had five hundred years of democracy and peace-and what did that produce? The cuckoo clock'. Orson Welles as Harry Lime: The Third Man. Orson Welles might have been a little unfair on the Swiss, after all cuckoo clocks were developed in the Schwartzwald, but, more importantly, Swiss democracy gives remarkably stable government with considerable decision-making at the local level. The alternative is the battling city-states of Renaissance Italy: culturally rich but chaotic at a higher level of organization. As our understanding of the cell cycle improves, it appears that the cell is organized more along the lines of Switzerland than Renaissance Italy, and one major challenge is to determine how local decisions are made and coordinated to produce the robust cell cycle mechanisms that we observe in the cell as a whole.

  15. Synthetic clock transitions via continuous dynamical decoupling

    Science.gov (United States)

    Trypogeorgos, D.; Valdés-Curiel, A.; Lundblad, N.; Spielman, I. B.

    2018-01-01

    Decoherence of quantum systems due to uncontrolled fluctuations of the environment presents fundamental obstacles in quantum science. Clock transitions which are insensitive to such fluctuations are used to improve coherence, however, they are not present in all systems or for arbitrary system parameters. Here we create a trio of synthetic clock transitions using continuous dynamical decoupling in a spin-1 Bose-Einstein condensate in which we observe a reduction of sensitivity to magnetic-field noise of up to four orders of magnitude; this work complements the parallel work by Anderson et al. [R. P. Anderson et al., following paper, Phys. Rev. A 97, 013408 (2018), 10.1103/PhysRevA.97.013408]. In addition, using a concatenated scheme, we demonstrate suppression of sensitivity to fluctuations in our control fields. These field-insensitive states represent an ideal foundation for the next generation of cold-atom experiments focused on fragile many-body phases relevant to quantum magnetism, artificial gauge fields, and topological matter.

  16. Temperature-Compensated Clock Skew Adjustment

    Directory of Open Access Journals (Sweden)

    Joaquín Olivares

    2013-08-01

    Full Text Available This work analyzes several drift compensation mechanisms in wireless sensor networks (WSN. Temperature is an environmental factor that greatly affects oscillators shipped in every WSN mote. This behavior creates the need of improving drift compensation mechanisms in synchronization protocols. Using the Flooding Time Synchronization Protocol (FTSP, this work demonstrates that crystal oscillators are affected by temperature variations. Thus, the influence of temperature provokes a low performance of FTSP in changing conditions of temperature. This article proposes an innovative correction factor that minimizes the impact of temperature in the clock skew. By means of this factor, two new mechanisms are proposed in this paper: the Adjusted Temperature (AT and the Advanced Adjusted Temperature (A2T. These mechanisms have been combined with FTSP to produce AT-FTSP and A2T-FTSP. Both have been tested in a network of TelosB motes running TinyOS. Results show that both AT-FTSP and A2T-FTSP improve the average synchronization errors compared to FTSP and other temperature-compensated protocols (Environment-Aware Clock Skew Estimation and Synchronization for WSN (EACS and Temperature Compensated Time Synchronization (TCTS.

  17. Circadian clock genes universally control key agricultural traits

    Science.gov (United States)

    Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and year. The circadian clock regulates a number of central plant activities, includin...

  18. Verge and Foliot Clock Escapement: A Simple Dynamical System

    Science.gov (United States)

    Denny, Mark

    2010-01-01

    The earliest mechanical clocks appeared in Europe in the 13th century. From about 1250 CE to 1670 CE, these simple clocks consisted of a weight suspended from a rope or chain that was wrapped around a horizontal axle. To tell time, the weight must fall with a slow uniform speed, but, under the action of gravity alone, such a suspended weight would…

  19. A CONSTANT-FREQUENCY POWER SUPPLY FOR SHIPBOARD ELECTRIC CLOCKS,

    Science.gov (United States)

    static inverter-type power supply , capable of powering up to six internally illuminated clocks per MIL-C-23339, with timekeeping accuracy better than...of a development model of this power supply are described. It is recommended that units of this type be procured for installation in control spaces of ships equipped with electric clocks. (Author)

  20. Self-clocked sequential circuits: - a design example | Aghdasi ...

    African Journals Online (AJOL)

    A number of new design methodologies which involve locally generating a clock and using it to self synchronize the machine have been proposed. Such clock signals are generated whenever an input changes, or by controlled excitation whenever a change of inputs necessitates a change of state. All such designs, where ...

  1. Optimal Infinite Runs in One-Clock Priced Timed Automata

    DEFF Research Database (Denmark)

    David, Alexandre; Ejsing-Duun, Daniel; Fontani, Lisa

    We address the problem of finding an infinite run with the optimal cost-time ratio in a one-clock priced timed automaton and pro- vide an algorithmic solution. Through refinements of the quotient graph obtained by strong time-abstracting bisimulation partitioning, we con- struct a graph with time...... of the one-clock priced timed automaton....

  2. Determination of clock synchronization errors in distributed networks

    NARCIS (Netherlands)

    Xia, Weiguo; Cao, Ming

    2018-01-01

    It has been shown by Freris, Graham and Kumar that clocks in distributed networks cannot be synchronized precisely in the presence of asymmetric time delays even in idealized situations. Motivated by that impossibility result, we test under similar settings the performance of some existing clock

  3. A Novel Method of Clock Synchronization in Distributed Systems

    Science.gov (United States)

    Li, Gun; Niu, Meng-jie; Chai, Yang-shun; Chen, Xin; Ren, Yan-qiu

    2017-04-01

    Time synchronization plays an important role in the spacecraft formation flight and constellation autonomous navigation, etc. For the application of clock synchronization in a network system, it is not always true that all the observed nodes in the network are interconnected, therefore, it is difficult to achieve the high-precision time synchronization of a network system in the condition that a certain node can only obtain the measurement information of clock from a single neighboring node, but cannot obtain it from other nodes. Aiming at this problem, a novel method of high-precision time synchronization in a network system is proposed. In this paper, each clock is regarded as a node in the network system, and based on the definition of different topological structures of a distributed system, the three control algorithms of time synchronization under the following three cases are designed: without a master clock (reference clock), with a master clock (reference clock), and with a fixed communication delay in the network system. And the validity of the designed clock synchronization protocol is proved by both stability analysis and numerical simulation.

  4. The circadian clock regulates auxin signaling and responses in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Michael F Covington

    2007-08-01

    Full Text Available The circadian clock plays a pervasive role in the temporal regulation of plant physiology, environmental responsiveness, and development. In contrast, the phytohormone auxin plays a similarly far-reaching role in the spatial regulation of plant growth and development. Went and Thimann noted 70 years ago that plant sensitivity to auxin varied according to the time of day, an observation that they could not explain. Here we present work that explains this puzzle, demonstrating that the circadian clock regulates auxin signal transduction. Using genome-wide transcriptional profiling, we found many auxin-induced genes are under clock regulation. We verified that endogenous auxin signaling is clock regulated with a luciferase-based assay. Exogenous auxin has only modest effects on the plant clock, but the clock controls plant sensitivity to applied auxin. Notably, we found both transcriptional and growth responses to exogenous auxin are gated by the clock. Thus the circadian clock regulates some, and perhaps all, auxin responses. Consequently, many aspects of plant physiology not previously thought to be under circadian control may show time-of-day-specific sensitivity, with likely important consequences for plant growth and environmental responses.

  5. The role of biological clock in glucose homeostasis 

    Directory of Open Access Journals (Sweden)

    Piotr Chrościcki

    2013-06-01

    Full Text Available The mechanism of the biological clock is based on a rhythmic expression of clock genes and clock-controlled genes. As a result of their transcripto-translational associations, endogenous rhythms in the synthesis of key proteins of various physiological and metabolic processes are created. The major timekeeping mechanism for these rhythms exists in the central nervous system. The master circadian clock, localized in suprachiasmatic nucleus (SCN, regulates multiple metabolic pathways, while feeding behavior and metabolite availability can in turn regulate the circadian clock. It is also suggested that in the brain there is a food entrainable oscillator (FEO or oscillators, resulting in activation of both food anticipatory activity and hormone secretion that control digestion processes. Moreover, most cells and tissues express autonomous clocks. Maintenance of the glucose homeostasis is particularly important for the proper function of the body, as this sugar is the main source of energy for the brain, retina, erythrocytes and skeletal muscles. Thus, glucose production and utilization are synchronized in time. The hypothalamic excited orexin neurons control energy balance of organism and modulate the glucose production and utilization. Deficiency of orexin action results in narcolepsy and weight gain, whereas glucose and amino acids can affect activity of the orexin cells. Large-scale genetic studies in rodents and humans provide evidence for the involvement of disrupted clock gene expression rhythms in the pathogenesis of obesity and type 2 diabetes. In general, the current lifestyle of the developed modern societies disturbs the action of biological clock

  6. Circadian clocks : from stem cells to tissue homeostasis and regeneration

    NARCIS (Netherlands)

    Dierickx, Pieterjan; Van Laake, Linda W; Geijsen, Niels

    2017-01-01

    The circadian clock is an evolutionarily conserved timekeeper that adapts body physiology to diurnal cycles of around 24 h by influencing a wide variety of processes such as sleep-to-wake transitions, feeding and fasting patterns, body temperature, and hormone regulation. The molecular clock

  7. Frequency comparison of optical lattice clocks beyond the Dick limit

    Science.gov (United States)

    Takamoto, Masao; Takano, Tetsushi; Katori, Hidetoshi

    2011-05-01

    The supreme accuracy of atomic clocks relies on the universality of atomic transition frequencies. The stability of a clock, meanwhile, measures how quickly the clock's statistical uncertainties are reduced. The ultimate measure of stability is provided by the quantum projection noise, which improves as 1/√N by measuring N uncorrelated atoms. Quantum projection noise limited stabilities have been demonstrated in caesium clocks and in single-ion optical clocks, where the quantum noise overwhelms the Dick effect attributed to local oscillator noise. Here, we demonstrate a synchronous frequency comparison of two optical lattice clocks using 87Sr and 88Sr atoms, respectively, for which the Allan standard deviation reached 1 × 10-17 in an averaging time of 1,600 s by cancelling out the Dick effect to approach the quantum projection noise limit. The scheme demonstrates the advantage of using a large number (N ~ 1,000) of atoms in optical clocks and paves the way to investigating the inherent uncertainties of clocks and relativistic geodesy on a timescale of tens of minutes.

  8. Development and entrainment of the colonic circadian clock during ontogenesis

    Czech Academy of Sciences Publication Activity Database

    Polidarová, Lenka; Olejníková, Lucie; Paušlyová, Lucia; Sládek, Martin; Soták, Matúš; Pácha, Jiří; Sumová, Alena

    2014-01-01

    Roč. 306, č. 4 (2014), G346-G356 ISSN 0193-1857 R&D Projects: GA ČR(CZ) GAP303/12/1108 Institutional support: RVO:67985823 Keywords : circadian clock * clock gene * ontogenesis * circadian entrainment Subject RIV: ED - Physiology Impact factor: 3.798, year: 2014

  9. LC-oscillator as a clock for data conversion

    NARCIS (Netherlands)

    Philips, K.J.P.; Verlinden, J.J.A.M.

    2006-01-01

    Following the ever-improving performance of data converters, the accuracy of the clock that is sampling the converter, needs to improveat the same pace. The clock accuracy is especially a problem for high-resolution, wide bandwidth converters.The aim of this project isto provide for a

  10. Clock synchronisation experiment in India using symphonie satellite

    Science.gov (United States)

    Somayajulu, Y. V.; Mathur, B. S.; Banerjee, P.; Garg, S. C.; Singh, L.; Sood, P. C.; Tyagi, T. R.; Jain, C. L.; Kumar, K.

    1979-01-01

    A recent clock synchronization experiment between the National Physical Laboratory (NPL), New Delhi and Space Applications Center (SAC), Ahemedabad, in India via geostationary satellite symphonie 2, stationed at 49 E longitude, is reported. A two-way transmission using a microwave transponder considered to provide the greatest precision in synchronization of two remote clocks is described.

  11. Axiomatisation of fully probabilistic design

    Czech Academy of Sciences Publication Activity Database

    Kárný, Miroslav; Kroupa, Tomáš

    2012-01-01

    Roč. 186, č. 1 (2012), s. 105-113 ISSN 0020-0255 R&D Projects: GA MŠk(CZ) 2C06001; GA ČR GA102/08/0567 Institutional research plan: CEZ:AV0Z10750506 Keywords : Bayesian decision making * Fully probabilistic design * Kullback–Leibler divergence * Unified decision making Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 3.643, year: 2012 http://library.utia.cas.cz/separaty/2011/AS/karny-0367271.pdf

  12. The quantum beat principles and applications of atomic clocks

    CERN Document Server

    Major, F

    2007-01-01

    This work attempts to convey a broad understanding of the physical principles underlying the workings of these quantum-based atomic clocks, with introductory chapters placing them in context with the early development of mechanical clocks and the introduction of electronic time-keeping as embodied in the quartz-controlled clocks. While the book makes no pretense at being a history of atomic clocks, it nevertheless takes a historical perspective in its treatment of the subject. Intended for nonspecialists with some knowledge of physics or engineering, The Quantum Beat covers a wide range of salient topics relevant to atomic clocks, treated in a broad intuitive manner with a minimum of mathematical formalism. Detailed descriptions are given of the design principles of the rubidium, cesium, hydrogen maser, and mercury ion standards; the revolutionary changes that the advent of the laser has made possible, such as laser cooling, optical pumping, the formation of "optical molasses," and the cesium "fountain" stand...

  13. A self-interfering clock as a "which path" witness.

    Science.gov (United States)

    Margalit, Yair; Zhou, Zhifan; Machluf, Shimon; Rohrlich, Daniel; Japha, Yonathan; Folman, Ron

    2015-09-11

    In Einstein's general theory of relativity, time depends locally on gravity; in standard quantum theory, time is global-all clocks "tick" uniformly. We demonstrate a new tool for investigating time in the overlap of these two theories: a self-interfering clock, comprising two atomic spin states. We prepare the clock in a spatial superposition of quantum wave packets, which evolve coherently along two paths into a stable interference pattern. If we make the clock wave packets "tick" at different rates, to simulate a gravitational time lag, the clock time along each path yields "which path" information, degrading the pattern's visibility. In contrast, in standard interferometry, time cannot yield "which path" information. This proof-of-principle experiment may have implications for the study of time and general relativity and their impact on fundamental effects such as decoherence and the emergence of a classical world. Copyright © 2015, American Association for the Advancement of Science.

  14. Standard Clock in primordial density perturbations and cosmic microwave background

    International Nuclear Information System (INIS)

    Chen, Xingang; Namjoo, Mohammad Hossein

    2014-01-01

    Standard Clocks in the primordial epoch leave a special type of features in the primordial perturbations, which can be used to directly measure the scale factor of the primordial universe as a function of time a(t), thus discriminating between inflation and alternatives. We have started to search for such signals in the Planck 2013 data using the key predictions of the Standard Clock. In this Letter, we summarize the key predictions of the Standard Clock and present an interesting candidate example in Planck 2013 data. Motivated by this candidate, we construct and compute full Standard Clock models and use the more complete prediction to make more extensive comparison with data. Although this candidate is not yet statistically significant, we use it to illustrate how Standard Clocks appear in Cosmic Microwave Background (CMB) and how they can be further tested by future data. We also use it to motivate more detailed theoretical model building

  15. The absolute frequency of the 87Sr optical clock transition

    DEFF Research Database (Denmark)

    Campbell, Gretchen K.; Ludlow, Andrew D.; Blatt, Sebastian

    2008-01-01

    The absolute frequency of the 1S0–3P0 clock transition of 87Sr has been measured to be 429 228 004 229 873.65 (37) Hz using lattice-confined atoms, where the fractional uncertainty of 8.6 × 10-16 represents one of the most accurate measurements of an atomic transition frequency to date. After...... a detailed study of systematic effects, which reduced the total systematic uncertainty of the Sr lattice clock to 1.5 × 10-16, the clock frequency is measured against a hydrogen maser which is simultaneously calibrated to the US primary frequency standard, the NIST Cs fountain clock, NIST-F1. The comparison...... is made possible using a femtosecond laser based optical frequency comb to phase coherently connect the optical and microwave spectral regions and by a 3.5 km fibre transfer scheme to compare the remotely located clock signals....

  16. Hyperpolarizability and Operational Magic Wavelength in an Optical Lattice Clock

    Science.gov (United States)

    Brown, R. C.; Phillips, N. B.; Beloy, K.; McGrew, W. F.; Schioppo, M.; Fasano, R. J.; Milani, G.; Zhang, X.; Hinkley, N.; Leopardi, H.; Yoon, T. H.; Nicolodi, D.; Fortier, T. M.; Ludlow, A. D.

    2017-12-01

    Optical clocks benefit from tight atomic confinement enabling extended interrogation times as well as Doppler- and recoil-free operation. However, these benefits come at the cost of frequency shifts that, if not properly controlled, may degrade clock accuracy. Numerous theoretical studies have predicted optical lattice clock frequency shifts that scale nonlinearly with trap depth. To experimentally observe and constrain these shifts in an 171Yb optical lattice clock, we construct a lattice enhancement cavity that exaggerates the light shifts. We observe an atomic temperature that is proportional to the optical trap depth, fundamentally altering the scaling of trap-induced light shifts and simplifying their parametrization. We identify an "operational" magic wavelength where frequency shifts are insensitive to changes in trap depth. These measurements and scaling analysis constitute an essential systematic characterization for clock operation at the 10-18 level and beyond.

  17. Molecular Mechanisms Regulating Temperature Compensation of the Circadian Clock

    Directory of Open Access Journals (Sweden)

    David M. Virshup

    2017-04-01

    Full Text Available An approximately 24-h biological timekeeping mechanism called the circadian clock is present in virtually all light-sensitive organisms from cyanobacteria to humans. The clock system regulates our sleep–wake cycle, feeding–fasting, hormonal secretion, body temperature, and many other physiological functions. Signals from the master circadian oscillator entrain peripheral clocks using a variety of neural and hormonal signals. Even centrally controlled internal temperature fluctuations can entrain the peripheral circadian clocks. But, unlike other chemical reactions, the output of the clock system remains nearly constant with fluctuations in ambient temperature, a phenomenon known as temperature compensation. In this brief review, we focus on recent advances in our understanding of the posttranslational modifications, especially a phosphoswitch mechanism controlling the stability of PER2 and its implications for the regulation of temperature compensation.

  18. Optical clocks and their contribution to gravity modeling

    Science.gov (United States)

    Naeimi, Mohammad; Mohamadhosseini, Babak; Hatami, Mohsen

    2016-04-01

    Optical clocks, as one of the latest achievements in atomic and molecular physics, have applications more than timing, due to their accuracy and stability. In general relativity, gravitational potential differences in space and time, cause frequency difference in optical clocks. Hence, ultra precise optical clocks can be used as a tool to observe potential differences and consequently as a new gravimetry technique. In this contribution, we investigate the latest optical clocks based on atomic transition in Al+ and derive a simple equation for frequency change related to geo-potential differences. Moreover, we consider the capability of optical clocks for gravity modeling in combination with other gravity observations. Finally, the possibility to detect potential changes in geo-dynamically active zones, such as East-Asia and the requirements for such studies are discussed.

  19. Standard Clock in primordial density perturbations and cosmic microwave background

    Directory of Open Access Journals (Sweden)

    Xingang Chen

    2014-12-01

    Full Text Available Standard Clocks in the primordial epoch leave a special type of features in the primordial perturbations, which can be used to directly measure the scale factor of the primordial universe as a function of time a(t, thus discriminating between inflation and alternatives. We have started to search for such signals in the Planck 2013 data using the key predictions of the Standard Clock. In this Letter, we summarize the key predictions of the Standard Clock and present an interesting candidate example in Planck 2013 data. Motivated by this candidate, we construct and compute full Standard Clock models and use the more complete prediction to make more extensive comparison with data. Although this candidate is not yet statistically significant, we use it to illustrate how Standard Clocks appear in Cosmic Microwave Background (CMB and how they can be further tested by future data. We also use it to motivate more detailed theoretical model building.

  20. A New Trapped Ion Clock Based on Hg-201(+)

    Science.gov (United States)

    Taghavi-Larigani, S.; Burt, E. A.; Lea, S. N.; Prestage, J. D.; Tjoelker, R. L.

    2009-01-01

    There are two stable odd isotopes of mercury with singly ionized hyperfine structure suitable for a microwave clock: Hg-199(+) and Hg-201(+). Virtually all trapped mercury ion clocks to date have used the 199 isotope. We have begun to investigate the viability of a trapped ion clock based on Hg-201(+). We have measured the unperturbed frequency of the (S-2)(sub 1/2) F = 1, m(sub F) = 0 to (S-2)(sub 1/2) F = 2, m(sub F) = 0 clock transition to be 29.9543658211(2) GHz. In this paper we describe initial measurements with Hg-201(+) and new applications to clocks and fundamental physics.

  1. Fully Automatic In-Syringe Magnetic Stirring-Assisted Dispersive Liquid–Liquid Microextraction Hyphenated to High-Temperature Torch Integrated Sample Introduction System-Inductively Coupled Plasma Spectrometer with Direct Injection of the Organic Phase

    OpenAIRE

    Sánchez, Raquel; Horstkotte, Burkhard; Fikarová, Kateřina; Sklenářová, Hana; Maestre, Salvador E.; Miró, Manuel; Todolí Torró, José Luis

    2017-01-01

    A proof of concept study involving the online coupling of automatic dispersive liquid–liquid microextraction (DLLME) to inductively coupled plasma optical emission spectrometry (ICP OES) with direct introduction and analysis of the organic extract is herein reported for the first time. The flow-based analyzer features a lab-in-syringe (LIS) setup with an integrated stirring system, a Meinhard nebulizer in combination with a heated single-pass spray chamber, and a rotary injection valve, used ...

  2. The Retina and other Light Sensitive Ocular Clocks

    Science.gov (United States)

    Besharse, Joseph C.; McMahon, Douglas G.

    2017-01-01

    Ocular clocks, first identified in the retina, are also found in the retinal pigment epithelium (RPE), cornea and ciliary body. The retina is a complex tissue of many cell types and considerable effort has gone into determining which cell types exhibit clock properties. Current data suggest that photoreceptors as well as inner retinal neurons exhibit clock properties with photoreceptors dominating in non-mammalian vertebrates and inner retinal neurons dominating in mice. However, these differences may in part reflect the choice of circadian output, and it is likely that clock properties are widely dispersed among many retinal cell types. The phase of the retinal clock can be set directly by light. In non-mammalian vertebrates direct light sensitivity is commonplace among body clocks, but in mice only the retina and cornea retain direct light-dependent phase regulation. This distinguishes the retina and possibly other ocular clocks from peripheral oscillators whose phase depends on the pace-making properties of the hypothalamic central brain clock, the suprachiasmatic nuclei (SCN). However, in mice retinal circadian oscillations dampen quickly in isolation due to weak coupling of its individual cell autonomous oscillators and there is no evidence that retinal clocks are directly controlled through input from other oscillators. Retinal circadian regulation in both mammals and non-mammalian vertebrates uses melatonin and dopamine as dark- and light-adaptive neuromodulators respectively, and light can regulate circadian phase indirectly through dopamine signaling. The melatonin/dopamine system appears to have evolved among non-mammalian vertebrates and retained with modification in mammals. Circadian clocks in the eye are critical for optimum visual function where they play a role fine tuning visual sensitivity, and their disruption can impact diseases such as glaucoma or retinal degeneration syndromes. PMID:27095816

  3. Circadian Clock Involvement in Zooplankton Diel Vertical Migration.

    Science.gov (United States)

    Häfker, N Sören; Meyer, Bettina; Last, Kim S; Pond, David W; Hüppe, Lukas; Teschke, Mathias

    2017-07-24

    Biological clocks are a ubiquitous ancient and adaptive mechanism enabling organisms to anticipate environmental cycles and to regulate behavioral and physiological processes accordingly [1]. Although terrestrial circadian clocks are well understood, knowledge of clocks in marine organisms is still very limited [2-5]. This is particularly true for abundant species displaying large-scale rhythms like diel vertical migration (DVM) that contribute significantly to shaping their respective ecosystems [6]. Here we describe exogenous cycles and endogenous rhythms associated with DVM of the ecologically important and highly abundant planktic copepod Calanus finmarchicus. In the laboratory, C. finmarchicus shows circadian rhythms of DVM, metabolism, and most core circadian clock genes (clock, period1, period2, timeless, cryptochrome2, and clockwork orange). Most of these genes also cycle in animals assessed in the wild, though expression is less rhythmic at depth (50-140 m) relative to shallow-caught animals (0-50 m). Further, peak expressions of clock genes generally occurred at either sunset or sunrise, coinciding with peak migration times. Including one of the first field investigations of clock genes in a marine species [5, 7], this study couples clock gene measurements with laboratory and field data on DVM. While the mechanistic connection remains elusive, our results imply a high degree of causality between clock gene expression and one of the planet's largest daily migrations of biomass. We thus suggest that circadian clocks increase zooplankton fitness by optimizing the temporal trade-off between feeding and predator avoidance, especially when environmental drivers are weak or absent [8]. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Math Clock: Perangkat Penunjuk Waktu Kreatif untuk Olahraga Otak

    Directory of Open Access Journals (Sweden)

    Galuh Boy Hertantyo

    2014-11-01

    Full Text Available Brain is one of the most vital parts for humans, with the number of brain function that is needed for the body, the brain becomes a very important part of the human body. If there is damage to the brain will certainly cause the performance of the human body will not run properly. Because of that, it’s very important to maintain brain health. There is a way to maintain brain health, for example is by doing brain exercise. Examples of brain exercise is to do simple math calculations or doing brain games like sudoku. Because of that, created a tool that can help the brain to maintain brain exercise. The tool is called math clock. Making math clock tool consists of hardware and software. The hardware consists of RTC as real time data input, ATmega328 as microcontroller and dot matrix 32x16 as a tool to display the output that has been processed by the microcontroller. The software is built using C with Arduino IDE. Math clock will process the data from RTC then processed it, in microcontroller so when output displayed on dot matrix, output will be simple mathematical operation with real time clock data on it. Test results show that, math clock is capable of displaying a simple mathematical calculation operations such as addition, subtraction, multiplication and division. The mathematical operation that display on math clock, appears to be random, so it’s not triggered by same mathematical operation. In math clock the display will change every 20 second, so in 1 minute there are 3 different kinds of mathematical operations. The results of questionnaires of 10 different students, showed 9 out of 10 students said math clock is a tool that easy to use as a clock. Math clock will be alternative for doing brain exercise every day.

  5. An Overview of Monthly Rhythms and Clocks

    Directory of Open Access Journals (Sweden)

    Florian Raible

    2017-05-01

    Full Text Available Organisms have evolved to cope with geophysical cycles of different period lengths. In this review, we focus on the adaptations of animals to the lunar cycle, specifically, on the occurrence of biological rhythms with monthly (circalunar or semi-monthly (circasemilunar period lengths. Systematic experimental investigation, starting in the early twentieth century, has allowed scientists to distinguish between mythological belief and scientific facts concerning the influence of the lunar cycle on animals. These studies revealed that marine animals of various taxa exhibit circalunar or circasemilunar reproductive rhythms. Some of these rely on endogenous oscillators (circalunar or circasemilunar clocks, whereas others are directly driven by external cues, such as the changes in nocturnal illuminance. We review current insight in the molecular and cellular mechanisms involved in circalunar rhythms, focusing on recent work in corals, annelid worms, midges, and fishes. In several of these model systems, the transcript levels of some core circadian clock genes are affected by both light and endogenous circalunar oscillations. How these and other molecular changes relate to the changes in physiology or behavior over the lunar cycle remains to be determined. We further review the possible relevance of circalunar rhythms for terrestrial species, with a particular focus on mammalian reproduction. Studies on circalunar rhythms of conception or birth rates extend to humans, where the lunar cycle was suggested to also affect sleep and mental health. While these reports remain controversial, factors like the increase in “light pollution” by artificial light might contribute to discrepancies between studies. We finally discuss the existence of circalunar oscillations in mammalian physiology. We speculate that these oscillations could be the remnant of ancient circalunar oscillators that were secondarily uncoupled from a natural entrainment mechanism, but

  6. A Fully Implantable, NFC Enabled, Continuous Interstitial Glucose Monitor.

    Science.gov (United States)

    Anabtawi, Nijad; Freeman, Sabrina; Ferzli, Rony

    2016-02-01

    This work presents an integrated system-on-chip (SoC) that forms the core of a long-term, fully implantable, battery assisted, passive continuous glucose monitor. It integrates an amperometric glucose sensor interface, a near field communication (NFC) wireless front-end and a fully digital switched mode power management unit for supply regulation and on board battery charging. It uses 13.56 MHz (ISM) band to harvest energy and backscatter data to an NFC reader. System was implemented in 14nm CMOS technology and validated with post layout simulations.

  7. Application of a fully integrated photodegradation-detection flow-batch analysis system with an on-line preconcentration step for the determination of metsulfuron methyl in water samples.

    Science.gov (United States)

    Acebal, Carolina C; Grünhut, Marcos; Srámková, Ivana; Chocholouš, Petr; Lista, Adriana G; Sklenářová, Hana; Solich, Petr; Band, Beatriz S Fernández

    2014-11-01

    This work presents the development of a fully automated flow-batch analysis (FBA) system as a new approach for on-line preconcentration, photodegradation and fluorescence detection in a lab-constructed mixing chamber that was designed to perform these processes without sample dispersion. The system positions the mixing chamber into the detection system and varies the instrumental parameters according to the required photodegradation conditions. The developed FBA system is simple and easily coupled with any sample pretreatment without altering the configuration. This FBA system was implemented to photodegrade and determine the fluorescence of the degradation products of metsulfuron methyl (MSM), a naturally non-fluorescent herbicide of the sulfonylurea׳s family. An on-line solid phase extraction (SPE) and clean up procedure using a C18 minicolumn was coupled to the photodegradation-detection mixing chamber (PDMC) that was located in the spectrofluorometer. An enrichment factor of 27 was achieved. Photodegradation conditions have been optimized by considering the influence of the elution solvent on both the formation of the photoproduct and on the fluorescence signal. Under optimal conditions, the calibration for the MSM determination was linear over the range of 1.00-7.20 µg L(-1). The limit of detection (LOD) was 0.28 µg L(-1); the relative standard deviation was 2.0% and the sample throughput for the entire process was 3h(-1). The proposed method was applied to real water samples from the Bahía Blanca׳s agricultural region (Bahía Blanca, Buenos Aires, Argentina). This method obtained satisfactory recoveries with a range of 94.7-109.8%. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Cryptochrome mediates light-dependent magnetosensitivity of Drosophila's circadian clock.

    Directory of Open Access Journals (Sweden)

    Taishi Yoshii

    2009-04-01

    Full Text Available Since 1960, magnetic fields have been discussed as Zeitgebers for circadian clocks, but the mechanism by which clocks perceive and process magnetic information has remained unknown. Recently, the radical-pair model involving light-activated photoreceptors as magnetic field sensors has gained considerable support, and the blue-light photoreceptor cryptochrome (CRY has been proposed as a suitable molecule to mediate such magnetosensitivity. Since CRY is expressed in the circadian clock neurons and acts as a critical photoreceptor of Drosophila's clock, we aimed to test the role of CRY in magnetosensitivity of the circadian clock. In response to light, CRY causes slowing of the clock, ultimately leading to arrhythmic behavior. We expected that in the presence of applied magnetic fields, the impact of CRY on clock rhythmicity should be altered. Furthermore, according to the radical-pair hypothesis this response should be dependent on wavelength and on the field strength applied. We tested the effect of applied static magnetic fields on the circadian clock and found that flies exposed to these fields indeed showed enhanced slowing of clock rhythms. This effect was maximal at 300 muT, and reduced at both higher and lower field strengths. Clock response to magnetic fields was present in blue light, but absent under red-light illumination, which does not activate CRY. Furthermore, cry(b and cry(OUT mutants did not show any response, and flies overexpressing CRY in the clock neurons exhibited an enhanced response to the field. We conclude that Drosophila's circadian clock is sensitive to magnetic fields and that this sensitivity depends on light activation of CRY and on the applied field strength, consistent with the radical pair mechanism. CRY is widespread throughout biological systems and has been suggested as receptor for magnetic compass orientation in migratory birds. The present data establish the circadian clock of Drosophila as a model system

  9. GPS satellite clock determination in case of inter-frequency clock biases for triple-frequency precise point positioning

    Science.gov (United States)

    Guo, Jiang; Geng, Jianghui

    2017-12-01

    Significant time-varying inter-frequency clock biases (IFCBs) within GPS observations prevent the application of the legacy L1/L2 ionosphere-free clock products on L5 signals. Conventional approaches overcoming this problem are to estimate L1/L5 ionosphere-free clocks in addition to their L1/L2 counterparts or to compute IFCBs between the L1/L2 and L1/L5 clocks which are later modeled through a harmonic analysis. In contrast, we start from the undifferenced uncombined GNSS model and propose an alternative approach where a second satellite clock parameter dedicated to the L5 signals is estimated along with the legacy L1/L2 clock. In this manner, we do not need to rely on the correlated L1/L2 and L1/L5 ionosphere-free observables which complicates triple-frequency GPS stochastic models, or account for the unfavorable time-varying hardware biases in undifferenced GPS functional models since they can be absorbed by the L5 clocks. An extra advantage over the ionosphere-free model is that external ionosphere constraints can potentially be introduced to improve PPP. With 27 days of triple-frequency GPS data from globally distributed stations, we find that the RMS of the positioning differences between our GPS model and all conventional models is below 1 mm for all east, north and up components, demonstrating the effectiveness of our model in addressing triple-frequency observations and time-varying IFCBs. Moreover, we can combine the L1/L2 and L5 clocks derived from our model to calculate precisely the L1/L5 clocks which in practice only depart from their legacy counterparts by less than 0.006 ns in RMS. Our triple-frequency GPS model proves convenient and efficient in combating time-varying IFCBs and can be generalized to more than three frequency signals for satellite clock determination.

  10. Polarizabilities of the beryllium clock transition

    International Nuclear Information System (INIS)

    Mitroy, J.

    2010-01-01

    The polarizabilities of the three lowest states of the beryllium atom are determined from a large basis configuration interaction calculation. The polarizabilities of the 2s 2 1 S e ground state (37.73a 0 3 ) and the 2s2p 3 P 0 o metastable state (39.04a 0 3 ) are found to be very similar in size and magnitude. This leads to an anomalously small blackbody radiation shift at 300 K of -0.018(4) Hz for the 2s 2 1 S e -2s2p 3 P 0 o clock transition. Magic wavelengths for simultaneous trapping of the ground and metastable states are also computed.

  11. Clocks for quaternary environments in Australia

    International Nuclear Information System (INIS)

    Tuniz, C.

    2002-01-01

    The Australian continent offers a variety of natural systems where records of the Earth's past environment have been stored, including sediment cores, tree rings, rock surfaces and corals. Rock varnish, mud-wasp nests and pack-rat middens provide alternative archives for vegetation and environmental change in arid areas, where continuous sedimentary sequences or trees are not available. Each of these media contain specific information on past climatic conditions but we must determine their chronology and decipher the relevant environmental parameters. Cosmogenic radionuclides, such as 14 C, 10 Be, 26 Al and 36 Cl, analysed by accelerator mass spectrometry, provide valuable radiometric clocks to establish an absolute time scale for the environmental events of the Quaternary. U-series, potassium-argon, argonargon and optically stimulated luminescence are other dating methods used in palaeoenvironmental studies. ANSTO supports the Quaternary science community in Australia providing the analysis of long-lived radionuclides: some significant projects from this program will be illustrated. (author)

  12. Cosmic time dilation: The clock paradox revisited

    International Nuclear Information System (INIS)

    Tomaschitz, Roman

    2004-01-01

    The relativistic time dilation is reviewed in a cosmological context. We show that a clock or twin paradox does not arise if cosmic time is properly taken into account. The receding galaxy background provides a unique frame of reference, and the proper times of geodesic as well as accelerated observers can be linked to the universal cosmic time parameter. This suggests to compare the proper time differentials of the respective observers by determining their state of motion in the galaxy grid. In this way, each observer can figure out whether his proper time is dilated or contracted relative to any other. In particular one can come to unambiguous conclusions on the aging of uniformly moving observers, without reference to asymmetries in measurement procedures or accelerations they may have undergone

  13. Direct Repression of Evening Genes by CIRCADIAN CLOCK-ASSOCIATED1 in the Arabidopsis Circadian Clock.

    Science.gov (United States)

    Kamioka, Mari; Takao, Saori; Suzuki, Takamasa; Taki, Kyomi; Higashiyama, Tetsuya; Kinoshita, Toshinori; Nakamichi, Norihito

    2016-03-01

    The circadian clock is a biological timekeeping system that provides organisms with the ability to adapt to day-night cycles. Timing of the expression of four members of the Arabidopsis thaliana PSEUDO-RESPONSE REGULATOR(PRR) family is crucial for proper clock function, and transcriptional control of PRRs remains incompletely defined. Here, we demonstrate that direct regulation of PRR5 by CIRCADIAN CLOCK-ASSOCIATED1 (CCA1) determines the repression state of PRR5 in the morning. Chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) analyses indicated that CCA1 associates with three separate regions upstream of PRR5 CCA1 and its homolog LATE ELONGATED HYPOCOTYL (LHY) suppressed PRR5 promoter activity in a transient assay. The regions bound by CCA1 in the PRR5 promoter gave rhythmic patterns with troughs in the morning, when CCA1 and LHY are at high levels. Furthermore,ChIP-seq revealed that CCA1 associates with at least 449 loci with 863 adjacent genes. Importantly, this gene set contains genes that are repressed but upregulated incca1 lhy double mutants in the morning. This study shows that direct binding by CCA1 in the morning provides strong repression of PRR5, and repression by CCA1 also temporally regulates an evening-expressed gene set that includes PRR5. © 2016 American Society of Plant Biologists. All rights reserved.

  14. Somitogenesis clock-wave initiation requires differential decay and multiple binding sites for clock protein.

    Directory of Open Access Journals (Sweden)

    Mark Campanelli

    2010-04-01

    Full Text Available Somitogenesis is a process common to all vertebrate embryos in which repeated blocks of cells arise from the presomitic mesoderm (PSM to lay a foundational pattern for trunk and tail development. Somites form in the wake of passing waves of periodic gene expression that originate in the tailbud and sweep posteriorly across the PSM. Previous work has suggested that the waves result from a spatiotemporally graded control protein that affects the oscillation rate of clock-gene expression. With a minimally constructed mathematical model, we study the contribution of two control mechanisms to the initial formation of this gene-expression wave. We test four biologically motivated model scenarios with either one or two clock protein transcription binding sites, and with or without differential decay rates for clock protein monomers and dimers. We examine the sensitivity of wave formation with respect to multiple model parameters and robustness to heterogeneity in cell population. We find that only a model with both multiple binding sites and differential decay rates is able to reproduce experimentally observed waveforms. Our results show that the experimentally observed characteristics of somitogenesis wave initiation constrain the underlying genetic control mechanisms.

  15. Optical lattice clock with strontium atoms: a second generation of cold atom clocks

    International Nuclear Information System (INIS)

    Le Targat, R.

    2007-07-01

    Atomic fountains, based on a microwave transition of Cesium or Rubidium, constitute the state of the art atomic clocks, with a relative accuracy close to 10 -16 . It nevertheless appears today that it will be difficult to go significantly beyond this level with this kind of device. The use of an optical transition, the other parameters being unchanged, gives hope for a 4 or 5 orders of magnitude improvement of the stability and of the relative uncertainty on most systematic effects. As for motional effects on the atoms, they can be controlled on a very different manner if they are trapped in an optical lattice instead of experiencing a free ballistic flight stage, characteristic of fountains. The key point of this approach lies in the fact that the trap can be operated in such a way that a well chosen, weakly allowed, J=0 → J=0 clock transition can be free from light shift effects. In this respect, the strontium atom is one of the most promising candidate, the 1S 0 → 3P 0 transition has a natural width of 1 mHz, and several other easily accessible transitions can be used to efficiently laser cool atoms down to 10 μK. This thesis demonstrates the experimental feasibility of an optical lattice clock based on the strontium atom, and reports on a preliminary evaluation of the relative accuracy with the fermionic isotope 87 Sr, at a level of a few 10 -15 . (author)

  16. A strontium lattice clock with reduced blackbody radiation shift

    Energy Technology Data Exchange (ETDEWEB)

    Al-Masoudi, Ali Khalas Anfoos

    2016-09-30

    Optical clocks have been quickly moving to the forefront of the frequency standards field due to their high spectral resolution, and therefore the potential high stability and accuracy. The accuracy and stability of the optical clocks are nowadays two orders of magnitude better than microwave Cs clocks, which realize the SI second. Envisioned applications of highly accurate optical clocks are to perform tests of fundamental physics, for example, searching for temporal drifts of the fine structure constant α, violations of the Local Position Invariance (LPI), dark matter and dark energy, or to performance relativistic geodesy. In this work, the uncertainty of a strontium lattice clock, based on the {sup 1}S{sub 0}-{sup 3}P{sub 0} transition in {sup 87}Sr, due to the blackbody radiation (BBR) shift has been reduced to less than 1 x 10{sup -18} by more than one order of magnitude compared to the previous evaluation of the BBR shift uncertainty in this clock. The BBR shift has been reduced by interrogating the atoms in a cryogenic environment. The systematic uncertainty of the cryogenic lattice clock is evaluated to be 1.3 x 10{sup -17} which is dominated by the uncertainty of the AC Stark shift of the lattice laser and the uncertainty contribution of the BBR shift is negligible. Concerning the instability of the clock, the detection noise of the clock has been measured, and a model linking noise and clock instability has been developed. This noise model shows that, in our lattice clock, quantum projection noise is reached if more than 130 atoms are interrogated. By combining the noise model with the degradation due to the Dick effect reflecting the frequency noise of the interrogation laser, the instability of the clock is estimated to be 1.6 x 10{sup -16}/√(τ/s) in regular operation. During this work, several high-accuracy comparisons to other atomic clocks have been performed, including several absolute frequency measurements. The Sr clock transition frequency

  17. CLOCK Acetylates ASS1 to Drive Circadian Rhythm of Ureagenesis.

    Science.gov (United States)

    Lin, Ran; Mo, Yan; Zha, Haihong; Qu, Zhipeng; Xie, Pancheng; Zhu, Zheng-Jiang; Xu, Ying; Xiong, Yue; Guan, Kun-Liang

    2017-10-05

    In addition to responding to environmental entrainment with diurnal variation, metabolism is also tightly controlled by cell-autonomous circadian clock. Extensive studies have revealed key roles of transcription in circadian control. Post-transcriptional regulation for the rhythmic gating of metabolic enzymes remains elusive. Here, we show that arginine biosynthesis and subsequent ureagenesis are collectively regulated by CLOCK (circadian locomotor output cycles kaput) in circadian rhythms. Facilitated by BMAL1 (brain and muscle Arnt-like protein), CLOCK directly acetylates K165 and K176 of argininosuccinate synthase (ASS1) to inactivate ASS1, which catalyzes the rate-limiting step of arginine biosynthesis. ASS1 acetylation by CLOCK exhibits circadian oscillation in human cells and mouse liver, possibly caused by rhythmic interaction between CLOCK and ASS1, leading to the circadian regulation of ASS1 and ureagenesis. Furthermore, we also identified NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9 (NDUFA9) and inosine-5'-monophosphate dehydrogenase 2 (IMPDH2) as acetylation substrates of CLOCK. Taken together, CLOCK modulates metabolic rhythmicity by acting as a rhythmic acetyl-transferase for metabolic enzymes. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. How does general anaesthesia affect the circadian clock?

    Science.gov (United States)

    Poulsen, Raewyn C; Warman, Guy R; Sleigh, Jamie; Ludin, Nicola M; Cheeseman, James F

    2018-02-01

    Post-operative patients experience sleep disturbances. Animal studies demonstrate that general anaesthesia (GA) can disrupt circadian rhythms and cause changes in the molecular clock, indicating that anaesthesia contributes to post-operative circadian disruption. Here we review the effect of anaesthesia on the circadian clock and its rhythms in order to summarise current findings outline commonalities between studies and propose mechanisms by which effects may be mediated. 1) GA has strong effects on the main neurotransmitter systems linked with circadian control (Gamma aminobutyric acid/N-methyl-D-aspartate (GABA/NMDA)) and may act by interfering with light-entrainment of the clock. 2) Expression of the core clock gene per2 is inhibited by GA (possibly via a NMDA/glycogen synthase kinase 3β (GSK3β) pathway). 3) GA's effect on circadian rhythms appears greatest when administered during animals' active phases 4) GA may have different effects when administered under free-running and entrained conditions. 5) Anaesthesia may mimic the mechanism involved in adaptation of the clock to changes in daylength. There is agreement that GA can strongly affect the circadian clock. How anaesthesia-induced changes in the molecular clock lead to changes in behaviour remains unclear. The answer, and what it may mean for patients post-operatively, will rely on systematic studies at molecular, behavioural, and clinical levels using standardised protocols. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Diurnal Oscillations of Soybean Circadian Clock and Drought Responsive Genes

    Science.gov (United States)

    Marcolino-Gomes, Juliana; Rodrigues, Fabiana Aparecida; Fuganti-Pagliarini, Renata; Bendix, Claire; Nakayama, Thiago Jonas; Celaya, Brandon; Molinari, Hugo Bruno Correa; de Oliveira, Maria Cristina Neves; Harmon, Frank G.; Nepomuceno, Alexandre

    2014-01-01

    Rhythms produced by the endogenous circadian clock play a critical role in allowing plants to respond and adapt to the environment. While there is a well-established regulatory link between the circadian clock and responses to abiotic stress in model plants, little is known of the circadian system in crop species like soybean. This study examines how drought impacts diurnal oscillation of both drought responsive and circadian clock genes in soybean. Drought stress induced marked changes in gene expression of several circadian clock-like components, such as LCL1-, GmELF4- and PRR-like genes, which had reduced expression in stressed plants. The same conditions produced a phase advance of expression for the GmTOC1-like, GmLUX-like and GmPRR7-like genes. Similarly, the rhythmic expression pattern of the soybean drought-responsive genes DREB-, bZIP-, GOLS-, RAB18- and Remorin-like changed significantly after plant exposure to drought. In silico analysis of promoter regions of these genes revealed the presence of cis-elements associated both with stress and circadian clock regulation. Furthermore, some soybean genes with upstream ABRE elements were responsive to abscisic acid treatment. Our results indicate that some connection between the drought response and the circadian clock may exist in soybean since (i) drought stress affects gene expression of circadian clock components and (ii) several stress responsive genes display diurnal oscillation in soybeans. PMID:24475115

  20. GNSS Clock Error Impacts on Radio Occultation Retrievals

    Science.gov (United States)

    Weiss, Jan; Sokolovskiy, Sergey; Schreiner, Bill; Yoon, Yoke

    2017-04-01

    We assess the impacts of GPS and GLONASS clock errors on radio occultation retrieval of bending angle, refractivity, and temperature from low Earth orbit. The major contributing factor is the interpretation of GNSS clock offsets sampled at 30 sec or longer intervals. Using 1 Hz GNSS clock estimates as truth we apply several interpolation and fitting schemes to evaluate how they affect the accuracy of atmospheric retrieval products. The results are organized by GPS and GLONASS space vehicle and the GNSS clock interpolation/fitting scheme. We find that bending angle error is roughly similar for all current GPS transmitters (about 0.7 mcrad) but note some differences related to the type of atomic oscillator onboard the transmitter satellite. GLONASS bending angle errors show more variation over the constellation and are approximately two times larger than GPS. An investigation of the transmitter clock spectra reveals this is due to more power in periods between 2-10 sec. Retrieved refractivity and temperature products show clear differences between GNSS satellite generations, and indicate that GNSS clocks sampled at intervals smaller than 5 sec significantly improve accuracy, particularly for GLONASS. We conclude by summarizing the tested GNSS clock estimation and application strategies in the context of current and future radio occultation missions.

  1. Diurnal oscillations of soybean circadian clock and drought responsive genes.

    Directory of Open Access Journals (Sweden)

    Juliana Marcolino-Gomes

    Full Text Available Rhythms produced by the endogenous circadian clock play a critical role in allowing plants to respond and adapt to the environment. While there is a well-established regulatory link between the circadian clock and responses to abiotic stress in model plants, little is known of the circadian system in crop species like soybean. This study examines how drought impacts diurnal oscillation of both drought responsive and circadian clock genes in soybean. Drought stress induced marked changes in gene expression of several circadian clock-like components, such as LCL1-, GmELF4- and PRR-like genes, which had reduced expression in stressed plants. The same conditions produced a phase advance of expression for the GmTOC1-like, GmLUX-like and GmPRR7-like genes. Similarly, the rhythmic expression pattern of the soybean drought-responsive genes DREB-, bZIP-, GOLS-, RAB18- and Remorin-like changed significantly after plant exposure to drought. In silico analysis of promoter regions of these genes revealed the presence of cis-elements associated both with stress and circadian clock regulation. Furthermore, some soybean genes with upstream ABRE elements were responsive to abscisic acid treatment. Our results indicate that some connection between the drought response and the circadian clock may exist in soybean since (i drought stress affects gene expression of circadian clock components and (ii several stress responsive genes display diurnal oscillation in soybeans.

  2. Fully Kinetic Ion Models for Magnetized Plasma Simulations

    Science.gov (United States)

    Sturdevant, Benjamin J.

    This thesis focuses on the development of simulation models, based on fully resolving the gyro-motion of ions with the Lorentz force equations of motion, for studying low-frequency phenomena in well-magnetized plasma systems. Such models, known as fully kinetic ion models, offer formal simplicity over higher order gyrokinetic ion models and may provide an important validation tool or replacement for gyrokinetic ion models in applications where the gyrokinetic ordering assumptions are in question. Methods for dealing with the added difficulty of resolving the short time scales associated with the ion gyro-motion in fully kinetic ion models are explored with the use of graphics processing units (GPUs) and advanced time integration algorithms, including sub-cycling, orbit averaging and variational integrators. Theoretical work is performed to analyze the effects of the ion Bernstein modes, which are known to cause difficulties in simulations based on fully kinetic ion models. In addition, the first simulation results for the ion temperature gradient driven instability in toroidal geometry using a fully kinetic ion model are presented. Finally, during the course of this work, a method for analyzing the effects of a finite time step size and spatial grid in the delta-f approach to the particle-in-cell method was developed for the first time. This method was applied to an implicit time integration scheme and has revealed some unusual numerical properties related to the delta-f method.

  3. Circadian clocks, rhythmic synaptic plasticity and the sleep-wake cycle in zebrafish

    Directory of Open Access Journals (Sweden)

    Idan eElbaz

    2013-02-01

    Full Text Available The circadian clock and homeostatic processes are fundamental mechanisms that regulate sleep. Surprisingly, despite decades of research, we still do not know why we sleep. Intriguing hypotheses suggest that sleep regulates synaptic plasticity and consequently has a beneficial role in learning and memory. However, direct evidence is still limited and the molecular regulatory mechanisms remain unclear. The zebrafish provides a powerful vertebrate model system that enables simple genetic manipulation, imaging of neuronal circuits and synapses in living animals, and the monitoring of behavioral performance during day and night. Thus, the zebrafish has become an attractive model to study circadian and homeostatic processes that regulate sleep. Zebrafish clock- and sleep-related genes have been cloned, neuronal circuits that exhibit circadian rhythms of activity and synaptic plasticity have been studied, and rhythmic behavioral outputs have been characterized. Integration of this data could lead to a better understanding of sleep regulation. Here, we review the progress of circadian clock and sleep studies in zebrafish with special emphasis on the genetic and neuroendocrine mechanisms that regulate rhythms of melatonin secretion, structural synaptic plasticity, locomotor activity and sleep.

  4. Circadian clocks, rhythmic synaptic plasticity and the sleep-wake cycle in zebrafish.

    Science.gov (United States)

    Elbaz, Idan; Foulkes, Nicholas S; Gothilf, Yoav; Appelbaum, Lior

    2013-01-01

    The circadian clock and homeostatic processes are fundamental mechanisms that regulate sleep. Surprisingly, despite decades of research, we still do not know why we sleep. Intriguing hypotheses suggest that sleep regulates synaptic plasticity and consequently has a beneficial role in learning and memory. However, direct evidence is still limited and the molecular regulatory mechanisms remain unclear. The zebrafish provides a powerful vertebrate model system that enables simple genetic manipulation, imaging of neuronal circuits and synapses in living animals, and the monitoring of behavioral performance during day and night. Thus, the zebrafish has become an attractive model to study circadian and homeostatic processes that regulate sleep. Zebrafish clock- and sleep-related genes have been cloned, neuronal circuits that exhibit circadian rhythms of activity and synaptic plasticity have been studied, and rhythmic behavioral outputs have been characterized. Integration of this data could lead to a better understanding of sleep regulation. Here, we review the progress of circadian clock and sleep studies in zebrafish with special emphasis on the genetic and neuroendocrine mechanisms that regulate rhythms of melatonin secretion, structural synaptic plasticity, locomotor activity and sleep.

  5. Microfabricated rubidium vapour cell with a thick glass core for small-scale atomic clock applications

    International Nuclear Information System (INIS)

    Pétremand, Y; Straessle, R; Briand, D; De Rooij, N F; Affolderbach, C; Pellaton, M; Mileti, G

    2012-01-01

    This paper presents a new fabrication method to manufacture alkali reference cells having dimensions larger than standard micromachined cells and smaller than glass-blown ones, for use in compact atomic devices such as vapour-cell atomic clocks or magnetometers. The technology is based on anodic bonding of silicon and relatively thick glass wafers and fills a gap in cell sizes and technologies available up to now: on one side, microfabrication technologies with typical dimensions ≤ 2 mm and on the other side, classical glass-blowing technologies for typical dimensions of about 6–10 mm or larger. The fabrication process is described for cells containing atomic Rb and spectroscopic measurements (optical absorption spectrum and double resonance) are reported. The analysis of the bonding strength of our cells was performed and shows that the first anodic bonding steps exhibit higher bonding strengths than the later ones. The spectroscopic results show a good quality of the cells. From the double-resonance signals, we predict a clock stability of ≈3 × 10 −11 at 1 s of integration time, which compares well to the performance of compact commercial Rb atomic clocks. (paper)

  6. Avoiding the Use of Exhausted Drinking Water Filters: A Filter-Clock Based on Rusting Iron

    Directory of Open Access Journals (Sweden)

    Arnaud Igor Ndé-Tchoupé

    2018-05-01

    Full Text Available Efficient but affordable water treatment technologies are currently sought to solve the prevalent shortage of safe drinking water. Adsorption-based technologies are in the front-line of these efforts. Upon proper design, universally applied materials (e.g., activated carbons, bone chars, metal oxides are able to quantitatively remove inorganic and organic pollutants as well as pathogens from water. Each water filter has a defined removal capacity and must be replaced when this capacity is exhausted. Operational experience has shown that it may be difficult to convince some low-skilled users to buy new filters after a predicted service life. This communication describes the quest to develop a filter-clock to encourage all users to change their filters after the designed service life. A brief discussion on such a filter-clock based on rusting of metallic iron (Fe0 is presented. Integrating such filter-clocks in the design of water filters is regarded as essential for safeguarding public health.

  7. High-precision multi-node clock network distribution

    Science.gov (United States)

    Chen, Xing; Cui, Yifan; Lu, Xing; Ci, Cheng; Zhang, Xuesong; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

    2017-10-01

    A high precision multi-node clock network for multiple users was built following the precise frequency transmission and time synchronization of 120 km fiber. The network topology adopts a simple star-shaped network structure. The clock signal of a hydrogen maser (synchronized with UTC) was recovered from a 120 km telecommunication fiber link and then was distributed to 4 sub-stations. The fractional frequency instability of all substations is in the level of 10-15 in a second and the clock offset instability is in sub-ps in root-mean-square average.

  8. Using optical clock to probe quantum many-body physics

    Science.gov (United States)

    Ye, Jun

    2016-05-01

    The progress of optical lattice clock has benefited greatly from the understanding of atomic interactions. At the same time, the precision of clock spectroscopy has been applied to explore many-body spin interactions including SU(N) symmetry. Our recent work on this combined front of quantum metrology and many-body physics includes the probe of spin-orbital physics in the lattice clock and the investigation of a Fermi degenerate gas of 105 87Sr atoms in a three-dimensional magic-wavelength optical lattice.

  9. Plant circadian clocks increase photosynthesis, growth, survival, and competitive advantage.

    Science.gov (United States)

    Dodd, Antony N; Salathia, Neeraj; Hall, Anthony; Kévei, Eva; Tóth, Réka; Nagy, Ferenc; Hibberd, Julian M; Millar, Andrew J; Webb, Alex A R

    2005-07-22

    Circadian clocks are believed to confer an advantage to plants, but the nature of that advantage has been unknown. We show that a substantial photosynthetic advantage is conferred by correct matching of the circadian clock period with that of the external light-dark cycle. In wild type and in long- and short-circadian period mutants of Arabidopsis thaliana, plants with a clock period matched to the environment contain more chlorophyll, fix more carbon, grow faster, and survive better than plants with circadian periods differing from their environment. This explains why plants gain advantage from circadian control.

  10. Open Core Protocol (OCP) Clock Domain Crossing Interfaces

    DEFF Research Database (Denmark)

    Herlev, Mathias; Poulsen, Christian Keis; Sparsø, Jens

    2014-01-01

    The open core protocol (OCP) is an openly licensed configurable and scalable interface protocol for on-chip subsystem communications. The protocol defines read and write transactions from a master towards a slave across a point-to-point connection and the protocol assumes a single common clock....... This paper presents the design of two OCP clock domain crossing interface modules that can be used to construct systems with multiple clock domains. An OCP interface typically has control signals related to both the master issuing a read or write request and the slave producing a response. If all...

  11. High-precision multi-node clock network distribution.

    Science.gov (United States)

    Chen, Xing; Cui, Yifan; Lu, Xing; Ci, Cheng; Zhang, Xuesong; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

    2017-10-01

    A high precision multi-node clock network for multiple users was built following the precise frequency transmission and time synchronization of 120 km fiber. The network topology adopts a simple star-shaped network structure. The clock signal of a hydrogen maser (synchronized with UTC) was recovered from a 120 km telecommunication fiber link and then was distributed to 4 sub-stations. The fractional frequency instability of all substations is in the level of 10 -15 in a second and the clock offset instability is in sub-ps in root-mean-square average.

  12. SOA-based clock recovery and demultiplexing in a lab trial of 640-Gb/s OTDM transmission over 50-km fibre link

    DEFF Research Database (Denmark)

    Tangdiongga, E.; Mulvad, Hans Christian Hansen; Waardt, H. de

    2007-01-01

    We report for the first time SOA-based clock recovery and demultiplexing of 40-Gb/s channels from 640 Gb/s OTDM signals over 50-km link. The system operates at low power and has the potential to be integrated.......We report for the first time SOA-based clock recovery and demultiplexing of 40-Gb/s channels from 640 Gb/s OTDM signals over 50-km link. The system operates at low power and has the potential to be integrated....

  13. Restaurant No. 1 fully renovated

    CERN Multimedia

    2007-01-01

    The Restaurant No. 1 team. After several months of patience and goodwill on the part of our clients, we are delighted to announce that the major renovation work which began in September 2006 has now been completed. From 21 May 2007 we look forward to welcoming you to a completely renovated restaurant area designed with you in mind. The restaurant team wishes to thank all its clients for their patience and loyalty. Particular attention has been paid in the new design to creating a spacious serving area and providing a wider choice of dishes. The new restaurant area has been designed as an open-plan space to enable you to view all the dishes before making your selection and to move around freely from one food access point to another. It comprises user-friendly areas that fully comply with hygiene standards. From now on you will be able to pick and choose to your heart's content. We invite you to try out wok cooking or some other speciality. Or select a pizza or a plate of pasta with a choice of two sauces fr...

  14. Search for top squark pair production in the fully hadronic final state in protonproton collisions at √s=13TeV corresponding to an integrated luminosity of 12.9 fb-1

    CERN Document Server

    Wahdan, Shayma'

    2016-01-01

    A search for direct production of top squark pairs is presented using data samples corresponding to integrated luminosities of 12.9 fb-1, collected at a centre-of-mass energy of 13 TeV with the CMS detector at the LHC. The search targets top squark (~t ) pair production in scenarios with mass difference Δm=m(~t )−m(~x 1 0) below the W-boson mass (where m(~x1 0) is the neutralino mass and m(~t ) is the top squark mass). So the final state products are low pT objects, using the Inclusive Vertix Finder (IVF) to search for the secondary vertices, reconstructed even in the absence of jets, helps us to identify the low pT b quarks from the top squark decays. The neutralino (~x1 0) is assumed to be the lightest supersymmetric particle (LSP). The signature includes an high transverse momentum jet associated with initial state radiation (ISR) in order to produce high missing transverse energy.

  15. Fully Automatic In-Syringe Magnetic Stirring-Assisted Dispersive Liquid-Liquid Microextraction Hyphenated to High-Temperature Torch Integrated Sample Introduction System-Inductively Coupled Plasma Spectrometer with Direct Injection of the Organic Phase.

    Science.gov (United States)

    Sánchez, Raquel; Horstkotte, Burkhard; Fikarová, Kateřina; Sklenářová, Hana; Maestre, Salvador; Miró, Manuel; Todolí, Jose-Luis

    2017-03-21

    A proof of concept study involving the online coupling of automatic dispersive liquid-liquid microextraction (DLLME) to inductively coupled plasma optical emission spectrometry (ICP OES) with direct introduction and analysis of the organic extract is herein reported for the first time. The flow-based analyzer features a lab-in-syringe (LIS) setup with an integrated stirring system, a Meinhard nebulizer in combination with a heated single-pass spray chamber, and a rotary injection valve, used as an online interface between the microextraction system and the detection instrument. Air-segmented flow was used for delivery of a fraction of the nonwater miscible extraction phase, 12 μL of xylene, to the nebulizer. All sample preparative steps including magnetic stirring assisted DLLME were carried out inside the syringe void volume as a size-adaptable yet sealed mixing and extraction chamber. Determination of trace level concentrations of cadmium, copper, lead, and silver as model analytes has been demonstrated by microextraction as diethyldithiophosphate (DDTP) complexes. The automatic LIS-DLLME method features quantitative metal extraction, even in troublesome sample matrixes, such as seawater, salt, and fruit juices, with relative recoveries within the range of 94-103%, 93-100%, and 92-99%, respectively. Furthermore, no statistically significant differences at the 0.05 significance level were found between concentration values experimentally obtained and the certified values of two serum standard reference materials.

  16. Major radiations in the evolution of Caviid rodents: reconciling fossils, ghost lineages, and relaxed molecular clocks.

    Science.gov (United States)

    Pérez, María Encarnación; Pol, Diego

    2012-01-01

    Caviidae is a diverse group of caviomorph rodents that is broadly distributed in South America and is divided into three highly divergent extant lineages: Caviinae (cavies), Dolichotinae (maras), and Hydrochoerinae (capybaras). The fossil record of Caviidae is only abundant and diverse since the late Miocene. Caviids belongs to Cavioidea sensu stricto (Cavioidea s.s.) that also includes a diverse assemblage of extinct taxa recorded from the late Oligocene to the middle Miocene of South America ("eocardiids"). A phylogenetic analysis combining morphological and molecular data is presented here, evaluating the time of diversification of selected nodes based on the calibration of phylogenetic trees with fossil taxa and the use of relaxed molecular clocks. This analysis reveals three major phases of diversification in the evolutionary history of Cavioidea s.s. The first two phases involve two successive radiations of extinct lineages that occurred during the late Oligocene and the early Miocene. The third phase consists of the diversification of Caviidae. The initial split of caviids is dated as middle Miocene by the fossil record. This date falls within the 95% higher probability distribution estimated by the relaxed Bayesian molecular clock, although the mean age estimate ages are 3.5 to 7 Myr older. The initial split of caviids is followed by an obscure period of poor fossil record (referred here as the Mayoan gap) and then by the appearance of highly differentiated modern lineages of caviids, which evidentially occurred at the late Miocene as indicated by both the fossil record and molecular clock estimates. The integrated approach used here allowed us identifying the agreements and discrepancies of the fossil record and molecular clock estimates on the timing of the major events in cavioid evolution, revealing evolutionary patterns that would not have been possible to gather using only molecular or paleontological data alone.

  17. Fully inkjet-printed microwave passive electronics

    KAUST Repository

    McKerricher, Garret

    2017-01-30

    Fully inkjet-printed three-dimensional (3D) objects with integrated metal provide exciting possibilities for on-demand fabrication of radio frequency electronics such as inductors, capacitors, and filters. To date, there have been several reports of printed radio frequency components metallized via the use of plating solutions, sputtering, and low-conductivity pastes. These metallization techniques require rather complex fabrication, and do not provide an easily integrated or versatile process. This work utilizes a novel silver ink cured with a low-cost infrared lamp at only 80 °C, and achieves a high conductivity of 1×107 S m−1. By inkjet printing the infrared-cured silver together with a commercial 3D inkjet ultraviolet-cured acrylic dielectric, a multilayer process is demonstrated. By using a smoothing technique, both the conductive ink and dielectric provide surface roughness values of <500 nm. A radio frequency inductor and capacitor exhibit state-of-the-art quality factors of 8 and 20, respectively, and match well with electromagnetic simulations. These components are implemented in a lumped element radio frequency filter with an impressive insertion loss of 0.8 dB at 1 GHz, proving the utility of the process for sensitive radio frequency applications.

  18. Regulation of behavioral circadian rhythms and clock protein PER1 by the deubiquitinating enzyme USP2

    DEFF Research Database (Denmark)

    Yang, Yaoming; Duguay, David; Bédard, Nathalie

    2012-01-01

    Endogenous 24-hour rhythms are generated by circadian clocks located in most tissues. The molecular clock mechanism is based on feedback loops involving clock genes and their protein products. Post-translational modifications, including ubiquitination, are important for regulating the clock...

  19. Toward A Neutral Mercury Optical Lattice Clock: Determination of the Magic Wavelength for the Ultraviolet clock Transition

    International Nuclear Information System (INIS)

    Mejri, Sinda

    2012-01-01

    A lattice clock combines the advantages of ion and neutral atom based clocks, namely the recoil and first order Doppler free spectroscopy allowed by the Lamb-Dicke regime. This lattice light field shifts the energy levels of the clock transition. However a wavelength can be found where the light-shift of the clock states cancelled to first order. In this thesis, we present the latest advances in optical lattice clock with mercury atoms developed at LNE-SYRTE. After a review of the current performances of different optical clock are currently under development, we focus on the concept of optical lattice clock and the features of the mercury that make him an excellent candidate for the realization of an optical lattice clock achievement the uncertainty of the level of 10 -17 . The second part is devoted to the characterization of the mercury MOT, using a sensitive detection system, which allowed us to evaluate the temperature of different isotopes present in the MOT and have a good evidence of sub-Doppler cooling for the fermionic isotopes. The third part of this these, present the experimental aspects of the implementation and the development of the laser source required for trapping mercury atoms operating near the predicted magic wavelength. Finally, we report on the Lamb-Dicke spectroscopy of the 1S0 →3 P0 clock transition in the 199 Hg atoms confined in lattice trap. With use of the ultra-stable laser system, linked to LNE-SYRTE primary frequency reference, we have determined the center frequency of the transition for a range of lattice wavelengths and different lattice depths. Analyzing these measurement, we have carried out the first experimental determination of the magic wavelength, which is the crucial step towards achieving a highly accurate frequency standard using mercury. (author)

  20. Non-uniform Solar Temperature Field on Large Aperture, Fully ...

    Indian Academy of Sciences (India)

    In this study, a 110-m fully steerable radio telescope was used as an analysis platform and the integral parametric finite element model of the antenna structure was built in the ANSYS thermal analysis module. The boundary conditions of periodic air temperature, solar radiation, long-wave radiation shadows of the ...

  1. Superradiance on the millihertz linewidth strontium clock transition

    Science.gov (United States)

    Norcia, Matthew A.; Winchester, Matthew N.; Cline, Julia R. K.; Thompson, James K.

    2016-01-01

    Laser frequency noise contributes a significant limitation to today’s best atomic clocks. A proposed solution to this problem is to create a superradiant laser using an optical clock transition as its gain medium. This laser would act as an active atomic clock and would be highly immune to the fluctuations in reference cavity length that limit today’s best lasers. We demonstrate and characterize superradiant emission from the millihertz linewidth clock transition in an ensemble of laser-cooled 87Sr atoms trapped within a high-finesse optical cavity. We measure a collective enhancement of the emission rate into the cavity mode by a factor of more than 10,000 compared to independently radiating atoms. We also demonstrate a method for seeding superradiant emission and observe interference between two independent transitions lasing simultaneously. We use this interference to characterize the relative spectral properties of the two lasing subensembles. PMID:27757423

  2. Multipolar Polarizabilities and Hyperpolarizabilities in the Sr Optical Lattice Clock

    Science.gov (United States)

    Porsev, S. G.; Safronova, M. S.; Safronova, U. I.; Kozlov, M. G.

    2018-02-01

    We address the problem of the lattice Stark shifts in the Sr clock caused by the multipolar M 1 and E 2 atom-field interactions and by the term nonlinear in lattice intensity and determined by the hyperpolarizability. We develop an approach to calculate hyperpolarizabilities for atoms and ions based on a solution of the inhomogeneous equation which allows us to effectively and accurately carry out complete summations over intermediate states. We apply our method to the calculation of the hyperpolarizabilities for the clock states in Sr. We also carry out an accurate calculation of the multipolar polarizabilities for these states at the magic frequency. Understanding these Stark shifts in optical lattice clocks is crucial for further improvement of the clock accuracy.

  3. The New PTB Caesium Fountain Clock CSF2

    National Research Council Canada - National Science Library

    Wynands, R; Bauch, A; Griebsch, D; Schroeder, R; Weyers, S

    2005-01-01

    At PTB a second caesium fountain clock, CSF2, is in the process of being set up. It differs from the first PTB caesium fountain standard CSF1 in a number of details, which are consecutively specified...

  4. A Summary of the GPS Constellation Clock Performance

    National Research Council Canada - National Science Library

    Oaks, Jay; Buisson, James A; Largay, Marie M

    2007-01-01

    ... (MCS) in Colorado Springs, Colorado. The analysis is based on clock estimates that NRL computes from GPS monitor station carrier-derived pseudo-range measurements and National Geospatial-Intelligence Agency (NGA...

  5. Cellular Clocks : Coupled Circadian Dispatch and Cell Division Cycles

    NARCIS (Netherlands)

    Merrow, Martha; Roenneberg, Till

    2004-01-01

    Gating of cell division by the circadian clock is well known, yet its mechanism is little understood. Genetically tractable model systems have led to new hypotheses and questions concerning the coupling of these two cellular cycles.

  6. CLOCK Genes and Circadian Rhythmicity in Alzheimer Disease

    Directory of Open Access Journals (Sweden)

    J. Thome

    2011-01-01

    Full Text Available Disturbed circadian rhythms with sleep problems and disrupted diurnal activity are often seen in patients suffering from Alzheimer disease (AD. Both endogenous CLOCK genes and external Zeitgeber are responsible for the maintenance of circadian rhythmicity in humans. Therefore, modifications of the internal CLOCK system and its interactions with exogenous factors might constitute the neurobiological basis for clinically observed disruptions in rhythmicity, which often have grave consequences for the quality of life of patients and their caregivers. Presently, more and more data are emerging demonstrating how alterations of the CLOCK gene system might contribute to the pathophysiology of AD and other forms of dementia. At the same time, the impact of neuropsychiatric medication on CLOCK gene expression is under investigation.

  7. Measurement of Magic Wavelengths for the ^{40}Ca^{+} Clock Transition.

    Science.gov (United States)

    Liu, Pei-Liang; Huang, Yao; Bian, Wu; Shao, Hu; Guan, Hua; Tang, Yong-Bo; Li, Cheng-Bin; Mitroy, J; Gao, Ke-Lin

    2015-06-05

    We demonstrate experimentally the existence of magic wavelengths and determine the ratio of oscillator strengths for a single trapped ion. For the first time, two magic wavelengths near 396 nm for the ^{40}Ca^{+} clock transition are measured simultaneously with high precision. By tuning the applied laser to an intermediate wavelength between transitions 4s_{1/2}→4p_{1/2} and 4s_{1/2}→4p_{3/2}, the sensitivity of the clock transition Stark shift to the oscillator strengths is greatly enhanced. Furthermore, with the measured magic wavelengths, we determine the ratio of the oscillator strengths with a deviation of less than 0.5%. Our experimental method may be applied to measure magic wavelengths for other ion clock transitions. Promisingly, the measurement of these magic wavelengths paves the way to building all-optical trapped ion clocks.

  8. Government and industry interactions in the development of clock technology

    Science.gov (United States)

    Hellwig, H.

    1981-01-01

    It appears likely that everyone in the time and frequency community can agree on goals to be realized through the expenditure of resources. These goals are the same as found in most fields of technology: lower cost, better performance, increased reliability, small size and lower power. Related aspects are examined in the process of clock and frequency standard development. Government and industry are reviewed in a highly interactive role. These interactions include judgements on clock performance, what kind of clock, expenditure of resources, transfer of ideas or hardware concepts from government to industry, and control of production. Successful clock development and production requires a government/industry relationship which is characterized by long-term continuity, multidisciplinary team work, focused funding and a separation of reliability and production oriented tasks from performance improvement/research type efforts.

  9. PHARAO space atomic clock: new developments on the laser source

    Science.gov (United States)

    Saccoccio, Muriel; Loesel, Jacques; Coatantiec, Claude; Simon, Eric; Laurent, Philippe; Lemonde, Pierre; Maksimovic, I.; Abgrall, M.

    2017-11-01

    The PHARAO project purpose is to open the way for a new atomic clock generation in space, where laser cooling techniques and microgravity allow high frequency stability and accuracy. The French space agency, CNES is funding and managing the clock construction. The French SYRTE and LKB laboratories are scientific and technical advisers for the clock requirements and the follow-up of subsystem development in industrial companies. EADS SODERN is developing two main subsystems of the PHARAO clock: the Laser Source and the Cesium Tube where atoms are cooled, launched, selected and detected by laser beams. The Laser Source includes an optical bench and electronic devices to generate the laser beams required. This paper describes PHARAO and the role laser beams play in its principle of operation. Then we present the Laser Source design, the technologies involved, and the status of development. Lastly, we focus of a key equipment to reach the performances expected, which is the Extended Cavity Laser Diode.

  10. Liter Sized Ion Clock with 10 (exp -15) Stability

    National Research Council Canada - National Science Library

    Prestage, J. D; Chang, S; Le, T; Lim, L; Maleki, L

    2005-01-01

    .... This development shows that Hmaser quality stabilities can be produced in a small clock package, comparable in size to an ultra-stable quartz oscillator required for holding 1-2x10-13 at 1 second...

  11. 'Integration'

    DEFF Research Database (Denmark)

    Olwig, Karen Fog

    2011-01-01

    , while the countries have adopted disparate policies and ideologies, differences in the actual treatment and attitudes towards immigrants and refugees in everyday life are less clear, due to parallel integration programmes based on strong similarities in the welfare systems and in cultural notions...

  12. The fully Mobile City Government Project (MCity)

    DEFF Research Database (Denmark)

    Scholl, Hans; Fidel, Raya; Mai, Jens Erik

    2006-01-01

    The Fully Mobile City Government Project, also known as MCity, is an interdisciplinary research project on the premises, requirements, and effects of fully mobile, wirelessly connected applications (FWMC). The project will develop an analytical framework for interpreting the interaction...

  13. Analysis and dimensioning of fully digital clock recovery for 112 Gb/s coherent polmux QPSK systems

    DEFF Research Database (Denmark)

    Zibar, Darko; Binaciotto, Alessandro; Wang, Zhe

    2009-01-01

    Combined effect of polarization mixing and Differential Group Delay (DGD) on sinusoidal and random jitter tolerance is investigated. Requirements for tolerable DGD, loop bandwidth and loop delay are extrapolated...

  14. Regulation of Clock Genes by Adrenergic Receptor Signaling in Osteoblasts.

    Science.gov (United States)

    Hirai, Takao

    2018-01-01

    The clock system has been identified as one of the major mechanisms controlling cellular functions. Circadian clock gene oscillations also actively participate in the functions of various cell types including bone-related cells. Previous studies demonstrated that clock genes were expressed in bone tissue and also that their expression exhibited circadian rhythmicity. Recent findings have shown that sympathetic tone plays a central role in biological oscillations in bone. Adrenergic receptor (AR) signaling regulates the expression of clock genes in cancellous bone. Furthermore, α 1 -AR signaling in osteoblasts is known to negatively regulate the expression of bone morphogenetic protein-4 (Bmp4) by up-regulating nuclear factor IL-3 (Nfil3)/e4 promoter-binding protein 4 (E4BP4). The ablation of α 1B -AR signaling also increases the expression of the Bmp4 gene in bone. The findings of transient overexpression and siRNA experiments have supported the involvement of the transcription factor CCAAT/enhancer-binding protein delta (C/EBPδ, Cebpd) in Nfil3 and Bmp4 expression in MC3T3-E1 cells. These findings suggest that the effects of Cebpd are due to the circadian regulation of Bmp4 expression, at least in part, by the up-regulated expression of the clock gene Nfil3 in response to α 1B -AR signaling in osteoblasts. Therefore, AR signaling appears to modulate cellular functionality through the expression of clock genes that are circadian rhythm regulators in osteoblasts. The expression of clock genes regulated by the sympathetic nervous system and clock-controlled genes that affect bone metabolism are described herein.

  15. Interpretable Machine Learning Models for the Digital Clock Drawing Test

    OpenAIRE

    Souillard-Mandar, William; Davis, Randall; Rudin, Cynthia; Au, Rhoda; Penney, Dana

    2016-01-01

    The Clock Drawing Test (CDT) is a rapid, inexpensive, and popular neuropsychological screening tool for cognitive conditions. The Digital Clock Drawing Test (dCDT) uses novel software to analyze data from a digitizing ballpoint pen that reports its position with considerable spatial and temporal precision, making possible the analysis of both the drawing process and final product. We developed methodology to analyze pen stroke data from these drawings, and computed a large collection of featu...

  16. Clock Face Drawing Test Performance in Children with ADHD

    Directory of Open Access Journals (Sweden)

    Ahmad Ghanizadeh

    2013-01-01

    Full Text Available  Introduction: The utility and discriminatory pattern of the clock face drawing test in ADHD is unclear. This study therefore compared Clock Face Drawing test performance in children with ADHD and controls.   Material & methods: 95 children with ADHD and 191 school children were matched for gender ratio and age. ADHD symptoms severities were assessed using DSM-IV ADHD checklist and their intellectual functioning was assessed. The participants completed three clock-drawing tasks, and the following four functions were assessed: Contour score, Numbers score, Hands setting score, and Center score    Results: All the subscales scores of the three clock drawing tests of the ADHD group were lower than that of the control group. In ADHD children, inattention and hyperactivity/impulsivity scores were not related with free drawn clock test scores. When pre-drawn contour test was performed, inattentiveness score was statistically associated with Number score. None of the other variables of age, gender, intellectual functioning, and hand use preference were associated with Numbers score. In pre-drawn clock, no association of ADHD symptoms with any CDT subscales was significant. In addition, more errors are observed with free drawn clock and Pre-drawn contour than pre-drawn clock.    Conclusion: Putting Numbers and Hands setting are more sensitive measures to screen ADHD than Contour and Center drawing. Test performance, except Hands setting, may have already reached a developmental plateau. It is probable that Hand setting deficit in children with ADHD may not decrease from age 8 to 14 years. Performance of children with ADHD is associated with the complexity of CDT.

  17. Clock Synchronization Through Time-Variant Underwater Acoustic Channels

    Science.gov (United States)

    2012-09-01

    Pulse Interval SPI Synchronizing Pulse Interval LFM Linear Frequency - Modulated PDF Probability Density Function... frequency - modulated (LFM) chirp trains and pseudorandom (PRN) binary sequences as the most suitable types of probe signals. A key attribute of LFM and PRN...Reference Clock (B) Synchroni zing Clock (A) x x x x b Reference Pulse Interval (RPI) Synchroni zation Pul se Interval (SPI) 1 2 i n...... A y y y

  18. Protecting Clock Synchronization: Adversary Detection through Network Monitoring

    OpenAIRE

    Elena Lisova; Marina Gutiérrez; Wilfried Steiner; Elisabeth Uhlemann; Johan Åkerberg; Radu Dobrin; Mats Björkman

    2016-01-01

    Nowadays, industrial networks are often used for safety-critical applications with real-time requirements. Such applications usually have a time-triggered nature with message scheduling as a core property. Scheduling requires nodes to share the same notion of time, that is, to be synchronized. Therefore, clock synchronization is a fundamental asset in real-time networks. However, since typical standards for clock synchronization, for example, IEEE 1588, do not provide the required level of se...

  19. CSAC Characterization and Its Impact on GNSS Clock Augmentation Performance

    Directory of Open Access Journals (Sweden)

    Enric Fernández

    2017-02-01

    Full Text Available Chip Scale Atomic Clocks (CSAC are recently-developed electronic instruments that, when used together with a Global Navigation Satellite Systems (GNSS receiver, help improve the performance of GNSS navigation solutions in certain conditions (i.e., low satellite visibility. Current GNSS receivers include a Temperature Compensated Cristal Oscillator (TCXO clock characterized by a short-term stability (τ = 1 s of 10−9 s that leads to an error of 0.3 m in pseudorange measurements. The CSAC can achieve a short-term stability of 2.5 × 10−12 s, which implies a range error of 0.075 m, making for an 87.5% improvement over TCXO. Replacing the internal TCXO clock of GNSS receivers with a higher frequency stability clock such as a CSAC oscillator improves the navigation solution in terms of low satellite visibility positioning accuracy, solution availability, signal recovery (holdover, multipath and jamming mitigation and spoofing attack detection. However, CSAC suffers from internal systematic instabilities and errors that should be minimized if optimal performance is desired. Hence, for operating CSAC at its best, the deterministic errors from the CSAC need to be properly modelled. Currently, this modelling is done by determining and predicting the clock frequency stability (i.e., clock bias and bias rate within the positioning estimation process. The research presented in this paper aims to go a step further, analysing the correlation between temperature and clock stability noise and the impact of its proper modelling in the holdover recovery time and in the positioning performance. Moreover, it shows the potential of fine clock coasting modelling. With the proposed model, an improvement in vertical positioning precision of around 50% with only three satellites can be achieved. Moreover, an increase in the navigation solution availability is also observed, a reduction of holdover recovery time from dozens of seconds to only a few can be achieved.

  20. CSAC Characterization and Its Impact on GNSS Clock Augmentation Performance.

    Science.gov (United States)

    Fernández, Enric; Calero, David; Parés, M Eulàlia

    2017-02-14

    Chip Scale Atomic Clocks (CSAC) are recently-developed electronic instruments that, when used together with a Global Navigation Satellite Systems (GNSS) receiver, help improve the performance of GNSS navigation solutions in certain conditions (i.e., low satellite visibility). Current GNSS receivers include a Temperature Compensated Cristal Oscillator (TCXO) clock characterized by a short-term stability ( τ = 1 s) of 10 -9 s that leads to an error of 0.3 m in pseudorange measurements. The CSAC can achieve a short-term stability of 2.5 × 10 -12 s, which implies a range error of 0.075 m, making for an 87.5% improvement over TCXO. Replacing the internal TCXO clock of GNSS receivers with a higher frequency stability clock such as a CSAC oscillator improves the navigation solution in terms of low satellite visibility positioning accuracy, solution availability, signal recovery (holdover), multipath and jamming mitigation and spoofing attack detection. However, CSAC suffers from internal systematic instabilities and errors that should be minimized if optimal performance is desired. Hence, for operating CSAC at its best, the deterministic errors from the CSAC need to be properly modelled. Currently, this modelling is done by determining and predicting the clock frequency stability (i.e., clock bias and bias rate) within the positioning estimation process. The research presented in this paper aims to go a step further, analysing the correlation between temperature and clock stability noise and the impact of its proper modelling in the holdover recovery time and in the positioning performance. Moreover, it shows the potential of fine clock coasting modelling. With the proposed model, an improvement in vertical positioning precision of around 50% with only three satellites can be achieved. Moreover, an increase in the navigation solution availability is also observed, a reduction of holdover recovery time from dozens of seconds to only a few can be achieved.

  1. Clocking In Turbines: Remarks On Physical Nature And Geometric Requirements

    Directory of Open Access Journals (Sweden)

    Swirydczuk Jerzy

    2015-04-01

    Full Text Available The article discusses two issues relating to the clocking phenomenon in turbines, which are the physical course of stator wake deformation in rotor passages and its further interaction with downstream stator blades, and turbine geometry parameters which are believed to be most favourable for clocking. In both cases, the results presented in the article have made it possible to verify and reformulate the previously accepted opinions.

  2. Deficiency of circadian protein CLOCK reduces lifespan and increases age-related cataract development in mice

    OpenAIRE

    Dubrovsky, Yuliya V.; Samsa, William E.; Kondratov, Roman V.

    2010-01-01

    Circadian clock is implicated in the regulation of aging. The transcription factor CLOCK, a core component of the circadian system, operates in complex with another circadian clock protein BMAL1. Recently it was demonstrated that BMAL1 deficiency results in premature aging in mice. Here we investigate the aging of mice deficient for CLOCK protein. Deficiency of the CLOCK protein significantly affects longevity: the average lifespan of Clock−/− mice is reduced by 15% compared with wild type mi...

  3. Clock Technology Development in the Laser Cooling and Atomic Physics (LCAP) Program

    Science.gov (United States)

    Seidel, Dave; Thompson, R. J.; Klipstein, W. M.; Kohel, J.; Maleki, L.

    2000-01-01

    This paper presents the Laser Cooling and Atomic Physics (LCAP) program. It focuses on clock technology development. The topics include: 1) Overview of LCAP Flight Projects; 2) Space Clock 101; 3) Physics with Clocks in microgravity; 4) Space Clock Challenges; 5) LCAP Timeline; 6) International Space Station (ISS) Science Platforms; 7) ISS Express Rack; 8) Space Qualification of Components; 9) Laser Configuration; 10) Clock Rate Comparisons: GPS Carrier Phase Frequency Transfer; and 11) ISS Model Views. This paper is presented in viewgraph form.

  4. IEEE 1588 clock distribution for FlexRIO devices in PXIe platforms

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, D., E-mail: dsanz@i2a2.upm.es [Grupo de Investigación en Instrumentación y Acústica Aplicada, Universidad Politécnica de Madrid, Madrid (Spain); Ruiz, M.; Lopez, J.M. [Grupo de Investigación en Instrumentación y Acústica Aplicada, Universidad Politécnica de Madrid, Madrid (Spain); Castro, R.; Vega, J. [Asociación EURATOM/CIEMAT, Madrid (Spain); Barrera, E. [Grupo de Investigación en Instrumentación y Acústica Aplicada, Universidad Politécnica de Madrid, Madrid (Spain)

    2014-05-15

    Highlights: • We explain briefly the synchronization process of the IEEE 1588 PTP. • Problems using PTP for integrate timestamp in PXIe ITER Fast Controllers prototype. • Integrate synchronized clock with PTP, into every FlexRIO device using PXIe bus. • Integrate solution with NIRIO EPICS Device Support for CODAC CORE System. • Synchronization accuracy obtained under 100 ns. - Abstract: In nuclear fusion environments, hundreds of thousands of data acquisition channels can be used. The time synchronization of these channels is crucial to obtaining a proper temporal correlation among the samples of all of the channels. Timestamping is the typical method used to provide a time reference to the samples. At present, the most accurate way to synchronize distributed data acquisition systems is to use the Precision Time Protocol (PTP) IEEE 1588 2008 standard, or its enhanced version, White Rabbit. The main problems related to this solution arise when the system controller in a chassis with more than one data acquisition (DAQ) device has to assign (a) timestamps to the concrete waveform samples acquired by each DAQ or has to (b) timestamp events generated by each DAQ under special conditions. One of the solutions adopted by ITER to implement the Fast Controller prototype consists of a controller device connected to a PXIe chassis with the NI-6682 timing card as the Timestamp generator and the FlexRIO devices as the DAQs. To solve this problem, a solution has been designed that distributes the clock from the IEEE 1588 timing card to all FlexRIO devices. Each DAQ device with its own clock is synchronized at every moment with the IEEE 1588 protocol, which has the capacity to assign timestamps to every sample acquired and to register events by hardware in a deterministic way. This solution increases the functionality of the NIRIO EPICS Device Support and can be included with the nominal device support that is a generic EPICS driver for every device type in the CODAC

  5. The quantum beat the physical principles of atomic clocks

    CERN Document Server

    Major, F G

    1998-01-01

    One of the indicators of the level of technological development of a society has been, throughout history, the precision of clocks it was able to build. This book examines the physical principles underlying the workings of clocks--from the earliest mechanical clocks to the present-day sophisticated clocks based on the properties of individual atoms. Intended for non-specialists with some knowledge of physics or engineering,the book treats the material in a broad intuitive manner, with a minimum of mathematical formalism. The presentation covers a broad range of salient topics relevant to the measurement of frequency and time intervals. The main focus is on electronic time-keeping: clocks based on quartz crystal oscillators and, at greater length, atomic clocks based on quantum resonance in rubidium, cesium, and hydrogen atoms, and, more recently, mercury ions. The book treats the revolutionary changes that the optical laser has wrought on atomic standards through laser cooling and optical pumping, and it disc...

  6. Redox regulation of circadian molecular clock in chronic airway diseases.

    Science.gov (United States)

    Sundar, Isaac K; Sellix, Michael T; Rahman, Irfan

    2017-10-31

    At the cellular level, circadian timing is maintained by the molecular clock, a family of interacting clock gene transcription factors, nuclear receptors and kinases called clock genes. Daily rhythms in pulmonary function are dictated by the circadian timing system, including rhythmic susceptibility to the harmful effects of airborne pollutants, exacerbations in patients with chronic airway disease and the immune-inflammatory response to infection. Further, evidence strongly suggests that the circadian molecular clock has a robust reciprocal interaction with redox signaling and plays a considerable role in the response to oxidative/carbonyl stress. Disruption of the circadian timing system, particularly in airway cells, impairs pulmonary rhythms and lung function, enhances oxidative stress due to airway inhaled pollutants like cigarette smoke and airborne particulate matter and leads to enhanced inflammosenescence, inflammasome activation, DNA damage and fibrosis. Herein, we briefly review recent evidence supporting the role of the lung molecular clock and redox signaling in regulating inflammation, oxidative stress, and DNA damage responses in lung diseases and their exacerbations. We further describe the potential for clock genes as novel biomarkers and therapeutic targets for the treatment of chronic lung diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. A clock network for geodesy and fundamental science.

    Science.gov (United States)

    Lisdat, C; Grosche, G; Quintin, N; Shi, C; Raupach, S M F; Grebing, C; Nicolodi, D; Stefani, F; Al-Masoudi, A; Dörscher, S; Häfner, S; Robyr, J-L; Chiodo, N; Bilicki, S; Bookjans, E; Koczwara, A; Koke, S; Kuhl, A; Wiotte, F; Meynadier, F; Camisard, E; Abgrall, M; Lours, M; Legero, T; Schnatz, H; Sterr, U; Denker, H; Chardonnet, C; Le Coq, Y; Santarelli, G; Amy-Klein, A; Le Targat, R; Lodewyck, J; Lopez, O; Pottie, P-E

    2016-08-09

    Leveraging the unrivalled performance of optical clocks as key tools for geo-science, for astronomy and for fundamental physics beyond the standard model requires comparing the frequency of distant optical clocks faithfully. Here, we report on the comparison and agreement of two strontium optical clocks at an uncertainty of 5 × 10(-17) via a newly established phase-coherent frequency link connecting Paris and Braunschweig using 1,415 km of telecom fibre. The remote comparison is limited only by the instability and uncertainty of the strontium lattice clocks themselves, with negligible contributions from the optical frequency transfer. A fractional precision of 3 × 10(-17) is reached after only 1,000 s averaging time, which is already 10 times better and more than four orders of magnitude faster than any previous long-distance clock comparison. The capability of performing high resolution international clock comparisons paves the way for a redefinition of the unit of time and an all-optical dissemination of the SI-second.

  8. The Molecular Circadian Clock and Alcohol-Induced Liver Injury

    Directory of Open Access Journals (Sweden)

    Uduak S. Udoh

    2015-10-01

    Full Text Available Emerging evidence from both experimental animal studies and clinical human investigations demonstrates strong connections among circadian processes, alcohol use, and alcohol-induced tissue injury. Components of the circadian clock have been shown to influence the pathophysiological effects of alcohol. Conversely, alcohol may alter the expression of circadian clock genes and the rhythmic behavioral and metabolic processes they regulate. Therefore, we propose that alcohol-mediated disruption in circadian rhythms likely underpins many adverse health effects of alcohol that cut across multiple organ systems. In this review, we provide an overview of the circadian clock mechanism and showcase results from new studies in the alcohol field implicating the circadian clock as a key target of alcohol action and toxicity in the liver. We discuss various molecular events through which alcohol may work to negatively impact circadian clock-mediated processes in the liver, and contribute to tissue pathology. Illuminating the mechanistic connections between the circadian clock and alcohol will be critical to the development of new preventative and pharmacological treatments for alcohol use disorders and alcohol-mediated organ diseases.

  9. Extracting dark matter signatures from atomic clock stability measurements

    Science.gov (United States)

    Kalaydzhyan, Tigran; Yu, Nan

    2017-10-01

    We analyze possible effects of the dark matter environment on the atomic clock stability measurements. The dark matter is assumed to exist in the form of waves of ultralight scalar fields or in the form of topological defects (monopoles and strings). We identify dark matter signal signatures in clock Allan deviation plots that can be used to constrain the dark matter coupling to the Standard Model fields. The existing data on the Al+/Hg+ clock comparison are used to put new limits on the dilaton dark matter in the region of masses mϕ>10-15 eV . We also estimate the sensitivities of future atomic clock experiments in space, including the cesium microwave and strontium optical clocks aboard the International Space Station, as well as a potential nuclear clock. These experiments are expected to put new limits on the topological dark matter in the range of masses 10-10 eV

  10. Atomic clocks and the continuous-time random-walk

    Science.gov (United States)

    Formichella, Valerio; Camparo, James; Tavella, Patrizia

    2017-11-01

    Atomic clocks play a fundamental role in many fields, most notably they generate Universal Coordinated Time and are at the heart of all global navigation satellite systems. Notwithstanding their excellent timekeeping performance, their output frequency does vary: it can display deterministic frequency drift; diverse continuous noise processes result in nonstationary clock noise (e.g., random-walk frequency noise, modelled as a Wiener process), and the clock frequency may display sudden changes (i.e., "jumps"). Typically, the clock's frequency instability is evaluated by the Allan or Hadamard variances, whose functional forms can identify the different operative noise processes. Here, we show that the Allan and Hadamard variances of a particular continuous-time random-walk, the compound Poisson process, have the same functional form as for a Wiener process with drift. The compound Poisson process, introduced as a model for observed frequency jumps, is an alternative to the Wiener process for modelling random walk frequency noise. This alternate model fits well the behavior of the rubidium clocks flying on GPS Block-IIR satellites. Further, starting from jump statistics, the model can be improved by considering a more general form of continuous-time random-walk, and this could bring new insights into the physics of atomic clocks.

  11. Influence of relativistic effects on satellite-based clock synchronization

    Science.gov (United States)

    Wang, Jieci; Tian, Zehua; Jing, Jiliang; Fan, Heng

    2016-03-01

    Clock synchronization between the ground and satellites is a fundamental issue in future quantum telecommunication, navigation, and global positioning systems. Here, we propose a scheme of near-Earth orbit satellite-based quantum clock synchronization with atmospheric dispersion cancellation by taking into account the spacetime background of the Earth. Two frequency entangled pulses are employed to synchronize two clocks, one at a ground station and the other at a satellite. The time discrepancy of the two clocks is introduced into the pulses by moving mirrors and is extracted by measuring the coincidence rate of the pulses in the interferometer. We find that the pulses are distorted due to effects of gravity when they propagate between the Earth and the satellite, resulting in remarkably affected coincidence rates. We also find that the precision of the clock synchronization is sensitive to the source parameters and the altitude of the satellite. The scheme provides a solution for satellite-based quantum clock synchronization with high precision, which can be realized, in principle, with current technology.

  12. Biological clocks and rhythms in intertidal crustaceans.

    Science.gov (United States)

    de la Iglesia, Horacio O; Hsu, Yun-Wei A

    2010-06-01

    Animals with habitats within the intertidal zone are exposed to environmental cycles that include the ebb and flow of tidal waters, changes in tidal levels associated with the lunar month, the light-dark cycle and the alternation of seasons. This intricate temporal environment results in the selection of biological timing systems with endogenous clocks that can oscillate with this wide range of periodicities. Whereas great progress has been made in our understanding of the molecular and neural bases of circadian rhythms, that is, endogenous rhythms synchronized to the solar day, there is little understanding on how circatidal rhythms, namely endogenous rhythms synchronized to tides, are generated. Intertidal crustaceans have been a pivotal group for the demonstration of the endogenous nature of circatidal rhythms and their mechanisms of entrainment. We review here some of the classic work using intertidal crustaceans to unmask basic properties of circatidal systems, as well as work from our laboratory that aims to identify putative chemical signals that could be involved in the circatidal systems of decapod crustaceans.

  13. Maternal feeding controls fetal biological clock.

    Directory of Open Access Journals (Sweden)

    Hidenobu Ohta

    Full Text Available BACKGROUND: It is widely accepted that circadian physiological rhythms of the fetus are affected by oscillators in the maternal brain that are coupled to the environmental light-dark (LD cycle. METHODOLOGY/PRINCIPAL FINDINGS: To study the link between fetal and maternal biological clocks, we investigated the effects of cycles of maternal food availability on the rhythms of Per1 gene expression in the fetal suprachiasmatic nucleus (SCN and liver using a transgenic rat model whose tissues express luciferase in vitro. Although the maternal SCN remained phase-locked to the LD cycle, maternal restricted feeding phase-advanced the fetal SCN and liver by 5 and 7 hours respectively within the 22-day pregnancy. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that maternal feeding entrains the fetal SCN and liver independently of both the maternal SCN and the LD cycle. This indicates that maternal-feeding signals can be more influential for the fetal SCN and particular organ oscillators than hormonal signals controlled by the maternal SCN, suggesting the importance of a regular maternal feeding schedule for appropriate fetal molecular clockwork during pregnancy.

  14. Reduced Voltage Scaling in Clock Distribution Networks

    Directory of Open Access Journals (Sweden)

    Khader Mohammad

    2009-01-01

    Full Text Available We propose a novel circuit technique to generate a reduced voltage swing (RVS signals for active power reduction on main buses and clocks. This is achieved without performance degradation, without extra power supply requirement, and with minimum area overhead. The technique stops the discharge path on the net that is swinging low at a certain voltage value. It reduces active power on the target net by as much as 33% compared to traditional full swing signaling. The logic 0 voltage value is programmable through control bits. If desired, the reduced-swing mode can also be disabled. The approach assumes that the logic 0 voltage value is always less than the threshold voltage of the nMOS receivers, which eliminate the need of the low to high voltage translation. The reduced noise margin and the increased leakage on the receiver transistors using this approach have been addressed through the selective usage of multithreshold voltage (MTV devices and the programmability of the low voltage value.

  15. Design principles of a genetic alarm clock.

    Directory of Open Access Journals (Sweden)

    Jaroslav Albert

    Full Text Available Turning genes on and off is a mechanism by which cells and tissues make phenotypic decisions. Gene network motifs capable of supporting two or more steady states and thereby providing cells with a plurality of possible phenotypes are referred to as genetic switches. Modeled on the bases of naturally occurring genetic networks, synthetic biologists have successfully constructed artificial switches, thus opening a door to new possibilities for improvement of the known, but also the design of new synthetic genetic circuits. One of many obstacles to overcome in such efforts is to understand and hence control intrinsic noise which is inherent in all biological systems. For some motifs the noise is negligible; for others, fluctuations in the particle number can be comparable to its average. Due to their slowed dynamics, motifs with positive autoregulation tend to be highly sensitive to fluctuations of their chemical environment and are in general very noisy, especially during transition (switching. In this article we use stochastic simulations (Gillespie algorithm to model such a system, in particular a simple bistable motif consisting of a single gene with positive autoregulation. Due to cooperativety, the dynamical behavior of this kind of motif is reminiscent of an alarm clock - the gene is (nearly silent for some time after it is turned on and becomes active very suddenly. We investigate how these sudden transitions are affected by noise and show that under certain conditions accurate timing can be achieved. We also examine how promoter complexity influences the accuracy of this timing mechanism.

  16. Design principles of a genetic alarm clock.

    Science.gov (United States)

    Albert, Jaroslav; Rooman, Marianne

    2012-01-01

    Turning genes on and off is a mechanism by which cells and tissues make phenotypic decisions. Gene network motifs capable of supporting two or more steady states and thereby providing cells with a plurality of possible phenotypes are referred to as genetic switches. Modeled on the bases of naturally occurring genetic networks, synthetic biologists have successfully constructed artificial switches, thus opening a door to new possibilities for improvement of the known, but also the design of new synthetic genetic circuits. One of many obstacles to overcome in such efforts is to understand and hence control intrinsic noise which is inherent in all biological systems. For some motifs the noise is negligible; for others, fluctuations in the particle number can be comparable to its average. Due to their slowed dynamics, motifs with positive autoregulation tend to be highly sensitive to fluctuations of their chemical environment and are in general very noisy, especially during transition (switching). In this article we use stochastic simulations (Gillespie algorithm) to model such a system, in particular a simple bistable motif consisting of a single gene with positive autoregulation. Due to cooperativety, the dynamical behavior of this kind of motif is reminiscent of an alarm clock - the gene is (nearly) silent for some time after it is turned on and becomes active very suddenly. We investigate how these sudden transitions are affected by noise and show that under certain conditions accurate timing can be achieved. We also examine how promoter complexity influences the accuracy of this timing mechanism.

  17. Cascaded clocks measurement and simulation findings

    Science.gov (United States)

    Chislow, Don; Zampetti, George

    1994-05-01

    This paper will examine aspects related to network synchronization distribution and the cascading of timing elements. Methods of timing distribution have become a much debated topic in standards forums and among network service providers (both domestically and internationally). Essentially these concerns focus on the need to migrate their existing network synchronization plans (and capabilities) to those required for the next generation of transport technologies (namely, the Synchronous Digital Hierarchy (SDH), Synchronous Optical Networks (SONET), and Asynchronous Transfer Mode (ATM). The particular choices for synchronization distribution network architectures are now being evaluated and are demonstrating that they can indeed have a profound effect on the overall service performance levels that will be delivered to the customer. The salient aspects of these concerns reduce to the following: (1) identifying that the devil is in the details of the timing element specifications and the distribution of timing information (i.e., small design choices can have a large performance impact); (2) developing a standardized method of performance verification that will yield unambiguous results; and (3) presentation of those results. Specifically, this will be done for two general cases: an ideal input, and a noisy input to a cascaded chain of slave clocks.

  18. Prediction of Navigation Satellite Clock Bias Considering Clock's Stochastic Variation Behavior with Robust Least Square Collocation

    Directory of Open Access Journals (Sweden)

    WANG Yupu

    2016-06-01

    Full Text Available In order to better express the characteristic of satellite clock bias (SCB and further improve its prediction precision, a new SCB prediction model is proposed, which can take the physical feature, cyclic variation and stochastic variation behaviors of the space-borne atomic clock into consideration by using a robust least square collocation (LSC method. The proposed model firstly uses a quadratic polynomial model with periodic terms to fit and abstract the trend term and cyclic terms of SCB. Then for the residual stochastic variation part and possible gross errors hidden in SCB data, the model employs a robust LSC method to process them. The covariance function of the LSC is determined by selecting an empirical function and combining SCB prediction tests. Using the final precise IGS SCB products to conduct prediction tests, the results show that the proposed model can get better prediction performance. Specifically, the results' prediction accuracy can enhance 0.457 ns and 0.948 ns respectively, and the corresponding prediction stability can improve 0.445 ns and 1.233 ns, compared with the results of quadratic polynomial model and grey model. In addition, the results also show that the proposed covariance function corresponding to the new model is reasonable.

  19. Strontium Optical Lattice Clock: In Quest of the Ultimate Performance

    International Nuclear Information System (INIS)

    Westergaard, Ph.G.

    2010-10-01

    This thesis presents the latest achievements regarding the Sr optical lattice clock experiment at LNESYRTE, Observatoire de Paris. After having described the general principles for optical lattice clocks and the operation of the clock in question, the emphasis is put on the features that have been added to the experiment since 2007. The most important new elements are an ultra-stable reference cavity for the clock laser, the development of a non-destructive detection technique, and the construction of a second Sr lattice clock. The ultra-stable cavity is constructed from a ULE spacer and fused silica mirrors and has shown a thermal noise floor at 6.5 * 10 -16 , placing it among the best in the world. The non-destructive detection is effectuated by a phase measurement of a weak probe beam that traverses the atoms placed in one arm of a Mach-Zender interferometer. The non-destructive aspect enables a recycling of the atoms from cycle to cycle which consequently increases the duty cycle, allowing for an increase of the stability of the clock. With these new tools the frequency stability is expected to be 2.2 * 10 -16 /√τ for an optimized sequence. The most recent comparisons between the two Sr clocks reach an accuracy level of 10 -16 after about 1000 s, and this way we have been able to characterize lattice related frequency shifts with an unprecedented accuracy. The measurements ensure a control of lattice related effects at the 10 -18 level even for trap depths as large as 50E r . (authors)

  20. British domestic synchronous clocks 1930-1980 the rise and fall of a technology

    CERN Document Server

    Pook, Leslie Philip

    2015-01-01

    This book complements available one-make books on domestic synchronous clocks. It is also a history of science book that sets British domestic synchronous clocks, their manufacturers and technology in their social context. Part I covers the historical background, British domestic synchronous clock manufacturers and brands, how synchronous clocks work, domestic synchronous clock cases, practical advice on the servicing of domestic synchronous clocks, and analysis of the marketing and reliability of British domestic synchronous clocks. This analysis provides an explanation of the rise and eventual fall of their technology. Part II contains galleries of a selection of British domestic synchronous clocks, and of the movements with which they are fitted. There is a front and back view of each clock, together with a brief description. Views of each movement include views with the movement partly dismantled, together with a brief technical description of the movement. This profusely illustrated book is primarily fo...

  1. Deleting the Arntl clock gene in the granular layer of the mouse cerebellum

    DEFF Research Database (Denmark)

    Bering, Tenna; Carstensen, Mikkel Bloss; Rath, Martin Fredensborg

    2017-01-01

    The suprachiasmatic nucleus houses the central circadian clock and is characterized by the timely regulated expression of clock genes. However, neurons of the cerebellar cortex also contain a circadian oscillator with circadian expression of clock genes being controlled by the suprachiasmatic...... is involved in circadian physiology and food anticipation, we therefore by use of Cre-LoxP technology generated a conditional knockout mouse with the core clock gene Arntl deleted specifically in granule cells of the cerebellum, since expression of clock genes in the cerebellar cortex is mainly located...... in this cell type. We here report that deletion of Arntl heavily influences the molecular clock of the cerebellar cortex with significantly altered and arrhythmic expression of other central clock and clock-controlled genes. On the other hand, daily expression of clock genes in the suprachiasmatic nucleus...

  2. Feasibility of Outpatient Fully Integrated Closed-Loop Control

    Science.gov (United States)

    Kovatchev, Boris P.; Renard, Eric; Cobelli, Claudio; Zisser, Howard C.; Keith-Hynes, Patrick; Anderson, Stacey M.; Brown, Sue A.; Chernavvsky, Daniel R.; Breton, Marc D.; Farret, Anne; Pelletier, Marie-Josée; Place, Jérôme; Bruttomesso, Daniela; Del Favero, Simone; Visentin, Roberto; Filippi, Alessio; Scotton, Rachele; Avogaro, Angelo; Doyle, Francis J.

    2013-01-01

    OBJECTIVE To evaluate the feasibility of a wearable artificial pancreas system, the Diabetes Assistant (DiAs), which uses a smart phone as a closed-loop control platform. RESEARCH DESIGN AND METHODS Twenty patients with type 1 diabetes were enrolled at the Universities of Padova, Montpellier, and Virginia and at Sansum Diabetes Research Institute. Each trial continued for 42 h. The United States studies were conducted entirely in outpatient setting (e.g., hotel or guest house); studies in Italy and France were hybrid hospital–hotel admissions. A continuous glucose monitoring/pump system (Dexcom Seven Plus/Omnipod) was placed on the subject and was connected to DiAs. The patient operated the system via the DiAs user interface in open-loop mode (first 14 h of study), switching to closed-loop for the remaining 28 h. Study personnel monitored remotely via 3G or WiFi connection to DiAs and were available on site for assistance. RESULTS The total duration of proper system communication functioning was 807.5 h (274 h in open-loop and 533.5 h in closed-loop), which represented 97.7% of the total possible time from admission to discharge. This exceeded the predetermined primary end point of 80% system functionality. CONCLUSIONS This study demonstrated that a contemporary smart phone is capable of running outpatient closed-loop control and introduced a prototype system (DiAs) for further investigation. Following this proof of concept, future steps should include equipping insulin pumps and sensors with wireless capabilities, as well as studies focusing on control efficacy and patient-oriented clinical outcomes. PMID:23801798

  3. Fossils and Dinosaurs--A Fully Integrated Instructional Unit.

    Science.gov (United States)

    Kuehl, Matt; And Others

    This lesson plan for the second and third grades uses information on dinosaurs, their adaptations and survival, to provide science education for limited-English-proficient (LEP) students in San Diego, California. The primary text is "Los Dinosaurios Gigantes," a core literature book used in the school district. Lessons are based on the whole…

  4. A fully integrated SWAT-MODFLOW hydrologic model

    Science.gov (United States)

    The Soil and Water Assessment Tool (SWAT) and MODFLOW models are being used worldwide for managing surface and groundwater water resources. The SWAT models hydrological processes occurring at the surface including shallow aquifers, while MODFLOW simulate groundwater processes. However, neither SWAT ...

  5. Universal interrogation protocol with zero probe-field-induced frequency shift for quantum clocks and high-accuracy spectroscopy

    Science.gov (United States)

    Zanon-Willette, T.; Lefevre, R.; Taichenachev, A. V.; Yudin, V. I.

    2017-08-01

    Optical clock interrogation protocols, based on laser-pulse spectroscopy, suffer from probe-induced frequency shifts and their variations induced by laser power. The original hyper-Ramsey probing scheme, which was proposed to alleviate those issues, does not fully eliminate the shift, especially when decoherence and relaxation by spontaneous emission or collisions are present. We propose to solve the fundamental problem of frequency shifts induced by the laser probe by deriving the exact canonical form of a multipulse generalized hyper-Ramsey resonance, including decoherence and relaxation. We present a universal interrogation protocol based on composite laser-pulse spectroscopy with phase modulation eliminating probe-induced frequency shifts at all orders in the presence of various dissipative processes. Unlike frequency shift extrapolation based methods, a universal interrogation protocol based on ±π /4 and ±3 π /4 phase-modulated resonances is proposed which does not compromise the stability of the optical clock while maintaining an ultrarobust error signal gradient in the presence of substantial uncompensated ac Stark shifts. Such a scheme can be implemented in two flavors: either by inverting clock state initialization or by pulse order reversal even without a perfect quantum state initialization. This universal interrogation protocol can be applied to atomic, molecular, and nuclear frequency metrology, mass spectrometry, and the field of precision spectroscopy. It might be designed using magic-wave-induced transitions, two-photon excitation, and magnetically induced spectroscopy or it might even be implemented with quantum logic gate circuit and qubit entanglement.

  6. Pacemaker-neuron–dependent disturbance of the molecular clockwork by a Drosophila CLOCK mutant homologous to the mouse Clock mutation

    Science.gov (United States)

    Lee, Euna; Cho, Eunjoo; Kang, Doo Hyun; Jeong, Eun Hee; Chen, Zheng; Yoo, Seung-Hee; Kim, Eun Young

    2016-01-01

    Circadian clocks are composed of transcriptional/translational feedback loops (TTFLs) at the cellular level. In Drosophila TTFLs, the transcription factor dCLOCK (dCLK)/CYCLE (CYC) activates clock target gene expression, which is repressed by the physical interaction with PERIOD (PER). Here, we show that amino acids (AA) 657–707 of dCLK, a region that is homologous to the mouse Clock exon 19-encoded region, is crucial for PER binding and E-box–dependent transactivation in S2 cells. Consistently, in transgenic flies expressing dCLK with an AA657–707 deletion in the Clock (Clkout) genetic background (p{dClk-Δ};Clkout), oscillation of core clock genes’ mRNAs displayed diminished amplitude compared with control flies, and the highly abundant dCLKΔ657–707 showed significantly decreased binding to PER. Behaviorally, the p{dClk-Δ};Clkout flies exhibited arrhythmic locomotor behavior in the photic entrainment condition but showed anticipatory activities of temperature transition and improved free-running rhythms in the temperature entrainment condition. Surprisingly, p{dClk-Δ};Clkout flies showed pacemaker-neuron–dependent alterations in molecular rhythms; the abundance of dCLK target clock proteins was reduced in ventral lateral neurons (LNvs) but not in dorsal neurons (DNs) in both entrainment conditions. In p{dClk-Δ};Clkout flies, however, strong but delayed molecular oscillations in temperature cycle-sensitive pacemaker neurons, such as DN1s and DN2s, were correlated with delayed anticipatory activities of temperature transition. Taken together, our study reveals that the LNv molecular clockwork is more sensitive than the clockwork of DNs to dysregulation of dCLK by AA657–707 deletion. Therefore, we propose that the dCLK/CYC-controlled TTFL operates differently in subsets of pacemaker neurons, which may contribute to their specific functions. PMID:27489346

  7. FAD Regulates CRYPTOCHROME Protein Stability and Circadian Clock in Mice.

    Science.gov (United States)

    Hirano, Arisa; Braas, Daniel; Fu, Ying-Hui; Ptáček, Louis J

    2017-04-11

    The circadian clock generates biological rhythms of metabolic and physiological processes, including the sleep-wake cycle. We previously identified a missense mutation in the flavin adenine dinucleotide (FAD) binding pocket of CRYPTOCHROME2 (CRY2), a clock protein that causes human advanced sleep phase. This prompted us to examine the role of FAD as a mediator of the clock and metabolism. FAD stabilized CRY proteins, leading to increased protein levels. In contrast, knockdown of Riboflavin kinase (Rfk), an FAD biosynthetic enzyme, enhanced CRY degradation. RFK protein levels and FAD concentrations oscillate in the nucleus, suggesting that they are subject to circadian control. Knockdown of Rfk combined with a riboflavin-deficient diet altered the CRY levels in mouse liver and the expression profiles of clock and clock-controlled genes (especially those related to metabolism including glucose homeostasis). We conclude that light-independent mechanisms of FAD regulate CRY and contribute to proper circadian oscillation of metabolic genes in mammals. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  8. FAD Regulates CRYPTOCHROME Protein Stability and Circadian Clock in Mice

    Directory of Open Access Journals (Sweden)

    Arisa Hirano

    2017-04-01

    Full Text Available The circadian clock generates biological rhythms of metabolic and physiological processes, including the sleep-wake cycle. We previously identified a missense mutation in the flavin adenine dinucleotide (FAD binding pocket of CRYPTOCHROME2 (CRY2, a clock protein that causes human advanced sleep phase. This prompted us to examine the role of FAD as a mediator of the clock and metabolism. FAD stabilized CRY proteins, leading to increased protein levels. In contrast, knockdown of Riboflavin kinase (Rfk, an FAD biosynthetic enzyme, enhanced CRY degradation. RFK protein levels and FAD concentrations oscillate in the nucleus, suggesting that they are subject to circadian control. Knockdown of Rfk combined with a riboflavin-deficient diet altered the CRY levels in mouse liver and the expression profiles of clock and clock-controlled genes (especially those related to metabolism including glucose homeostasis. We conclude that light-independent mechanisms of FAD regulate CRY and contribute to proper circadian oscillation of metabolic genes in mammals.

  9. Progress Toward a Compact, Highly Stable Ion Clock

    Science.gov (United States)

    Prestage, John; Chung, Sang

    2009-01-01

    There was an update on the subject of two previous NASA Tech Briefs articles: Compact, Highly Stable Ion Clock (NPO-43075), Vol. 32, No. 5 (May 2008), page 63; and Neon as a Buffer Gas for a Mercury-Ion Clock (NPO-42919), Vol. 32, No. 7 (July 2008), page 62. To recapitulate: A developmental miniature mercury-ion clock has stability comparable to that of a hydrogen-maser clock. The ion-handling components are housed in a sealed vacuum tube, wherein a getter pump maintains the partial vacuum, and the evacuated tube is backfilled with mercury vapor in a neon buffer gas. There was progress in the development of the clock, with emphasis on the design, fabrication, pump-down, and bake-out of the vacuum tube (based on established practice in the travelingwave- tube-amplifier industry) and the ability of the tube to retain a vacuum after a year of operation. Other developments include some aspects of the operation of mercury-vapor source (a small appendage oven containing HgO) so as to maintain the optimum low concentration of mercury vapor, and further efforts to miniaturize the vacuum and optical subsystems to fit within a volume of 2 L.

  10. Bone Resorption Is Regulated by Circadian Clock in Osteoblasts.

    Science.gov (United States)

    Takarada, Takeshi; Xu, Cheng; Ochi, Hiroki; Nakazato, Ryota; Yamada, Daisuke; Nakamura, Saki; Kodama, Ayumi; Shimba, Shigeki; Mieda, Michihiro; Fukasawa, Kazuya; Ozaki, Kakeru; Iezaki, Takashi; Fujikawa, Koichi; Yoneda, Yukio; Numano, Rika; Hida, Akiko; Tei, Hajime; Takeda, Shu; Hinoi, Eiichi

    2017-04-01

    We have previously shown that endochondral ossification is finely regulated by the Clock system expressed in chondrocytes during postnatal skeletogenesis. Here we show a sophisticated modulation of bone resorption and bone mass by the Clock system through its expression in bone-forming osteoblasts. Brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1) and Period1 (Per1) were expressed with oscillatory rhythmicity in the bone in vivo, and circadian rhythm was also observed in cultured osteoblasts of Per1::luciferase transgenic mice. Global deletion of murine Bmal1, a core component of the Clock system, led to a low bone mass, associated with increased bone resorption. This phenotype was recapitulated by the deletion of Bmal1 in osteoblasts alone. Co-culture experiments revealed that Bmal1-deficient osteoblasts have a higher ability to support osteoclastogenesis. Moreover, 1α,25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ]-induced receptor activator of nuclear factor κB ligand (Rankl) expression was more strongly enhanced in both Bmal1-deficient bone and cultured osteoblasts, whereas overexpression of Bmal1/Clock conversely inhibited it in osteoblasts. These results suggest that bone resorption and bone mass are regulated at a sophisticated level by osteoblastic Clock system through a mechanism relevant to the modulation of 1,25(OH) 2 D 3 -induced Rankl expression in osteoblasts. © 2017 American Society for Bone and Mineral Research. © 2017 American Society for Bone and Mineral Research.

  11. Neurogenetics of Drosophila circadian clock: expect the unexpected.

    Science.gov (United States)

    Jarabo, Patricia; Martin, Francisco A

    2017-12-01

    Daily biological rhythms (i.e. circadian) are a fundamental part of animal behavior. Numerous reports have shown disruptions of the biological clock in neurodegenerative disorders and cancer. In the latter case, only recently we have gained insight into the molecular mechanisms. After 45 years of intense study of the circadian rhtythms, we find surprising similarities among species on the molecular clock that governs biological rhythms. Indeed, Drosophila is one of the most widely used models in the study of chronobiology. Recent studies in the fruit fly have revealed unpredicted roles for the clock machinery in different aspects of behavior and physiology. Not only the central pacemaker cells do have non-classical circadian functions but also circadian genes work in other cells and tissues different from central clock neurons. In this review, we summarize these new evidences. We also recapitulate the most basic features of Drosophila circadian clock, including recent data about the inputs and outputs that connect the central pacemaker with other regions of the brain. Finally, we discuss the advantages and drawbacks of using natural versus laboratory conditions.

  12. The Circadian Clock-controlled Transcriptome of Developing Soybean Seeds

    Directory of Open Access Journals (Sweden)

    Karen A. Hudson

    2010-07-01

    Full Text Available A number of metabolic and physiological processes in plants are controlled by the circadian clock, which enables a plant to anticipate daily changes in the environment. Relatively little is known about circadian rhythms in developing seeds, which may be important for determining the extent and timing of nutrient storage in grain. Microarray expression profiling was used to identify genes expressed in developing soybean ( seeds that are controlled by the circadian clock. Genes with predicted functions in protein synthesis, fatty acid metabolism, and photosynthesis totaling 1.8% of the mRNAs detected in seed were found to be expressed in a circadian rhythm. Known circadian and light-controlled promoter elements were identified as over-represented in the promoters of clock-controlled seed genes, with the over-represented elements varying according to the phase of circadian expression. A subset of circadian-regulated genes were found to be expressed in different phases in developing seeds with respect to leaves from the same plants, many of which have roles in photosynthesis and carbon metabolism. These results help to characterize the genes and processes in seeds that may be regulated by the circadian clock, and provide some insight into organ-specific phasing of clock controlled gene expression.

  13. Protecting Clock Synchronization: Adversary Detection through Network Monitoring

    Directory of Open Access Journals (Sweden)

    Elena Lisova

    2016-01-01

    Full Text Available Nowadays, industrial networks are often used for safety-critical applications with real-time requirements. Such applications usually have a time-triggered nature with message scheduling as a core property. Scheduling requires nodes to share the same notion of time, that is, to be synchronized. Therefore, clock synchronization is a fundamental asset in real-time networks. However, since typical standards for clock synchronization, for example, IEEE 1588, do not provide the required level of security, it raises the question of clock synchronization protection. In this paper, we identify a way to break synchronization based on the IEEE 1588 standard, by conducting a man-in-the-middle (MIM attack followed by a delay attack. A MIM attack can be accomplished through, for example, Address Resolution Protocol (ARP poisoning. Using the AVISPA tool, we evaluate the potential to perform a delay attack using ARP poisoning and analyze its consequences showing both that the attack can, indeed, break clock synchronization and that some design choices, such as a relaxed synchronization condition mode, delay bounding, and using knowledge of environmental conditions, can make the network more robust/resilient against these kinds of attacks. Lastly, a Configuration Agent is proposed to monitor and detect anomalies introduced by an adversary performing attacks targeting clock synchronization.

  14. Trusted Fabrication through 3D Integration

    Science.gov (United States)

    2017-03-01

    designed to defeat this playbook. Obfuscation Concept The overall concept is shown in Figure 1. A digital netlist is partitioned into two almost...equal halves that can be fabricated as two separate chips to be integrated. An analog netlist would be partitioned by hand. A CAD tool flow is used... clock routing. (In hindsight this was a mistake and a simple 3D clock router should have been introduced.) Scripts keep track of matching connections

  15. The Effects of Race Conditions When Implementing Single-Source Redundant Clock Trees in Triple Modular Redundant Synchronous Architectures

    Science.gov (United States)

    Berg, Melanie D.; Kim, Hak S.; Phan, Anthony M.; Seidleck, Christina M.; Label, Kenneth A.; Pellish, Jonathan A.; Campola, Michael J.

    2016-01-01

    We present the challenges that arise when using redundant clock domains due to their time-skew. Radiation data show that a singular clock domain provides an improved triple modular redundant (TMR) scheme over redundant clocks.

  16. Fault-tolerant clock synchronization validation methodology. [in computer systems

    Science.gov (United States)

    Butler, Ricky W.; Palumbo, Daniel L.; Johnson, Sally C.

    1987-01-01

    A validation method for the synchronization subsystem of a fault-tolerant computer system is presented. The high reliability requirement of flight-crucial systems precludes the use of most traditional validation methods. The method presented utilizes formal design proof to uncover design and coding errors and experimentation to validate the assumptions of the design proof. The experimental method is described and illustrated by validating the clock synchronization system of the Software Implemented Fault Tolerance computer. The design proof of the algorithm includes a theorem that defines the maximum skew between any two nonfaulty clocks in the system in terms of specific system parameters. Most of these parameters are deterministic. One crucial parameter is the upper bound on the clock read error, which is stochastic. The probability that this upper bound is exceeded is calculated from data obtained by the measurement of system parameters. This probability is then included in a detailed reliability analysis of the system.

  17. Shell neurons of the master circadian clock coordinate the phase of tissue clocks throughout the brain and body.

    Science.gov (United States)

    Evans, Jennifer A; Suen, Ting-Chung; Callif, Ben L; Mitchell, Andrew S; Castanon-Cervantes, Oscar; Baker, Kimberly M; Kloehn, Ian; Baba, Kenkichi; Teubner, Brett J W; Ehlen, J Christopher; Paul, Ketema N; Bartness, Timothy J; Tosini, Gianluca; Leise, Tanya; Davidson, Alec J

    2015-06-23

    Daily rhythms in mammals are programmed by a master clock in the suprachiasmatic nucleus (SCN). The SCN contains two main compartments (shell and core), but the role of each region in system-level coordination remains ill defined. Herein, we use a functional assay to investigate how downstream tissues interpret region-specific outputs by using in vivo exposure to long day photoperiods to temporally dissociate the SCN. We then analyze resulting changes in the rhythms of clocks located throughout the brain and body to examine whether they maintain phase synchrony with the SCN shell or core. Nearly all of the 17 tissues examined in the brain and body maintain phase synchrony with the SCN shell, but not the SCN core, which indicates that downstream oscillators are set by cues controlled specifically by the SCN shell. Interestingly, we also found that SCN dissociation diminished the amplitude of rhythms in core clock gene and protein expression in brain tissues by 50-75 %, which suggests that light-driven changes in the functional organization of the SCN markedly influence the strength of rhythms in downstream tissues. Overall, our results reveal that body clocks receive time-of-day cues specifically from the SCN shell, which may be an adaptive design principle that serves to maintain system-level phase relationships in a changing environment. Further, we demonstrate that lighting conditions alter the amplitude of the molecular clock in downstream tissues, which uncovers a new form of plasticity that may contribute to seasonal changes in physiology and behavior.

  18. Conservation of Arabidopsis thaliana circadian clock genes in Chrysanthemum lavandulifolium.

    Science.gov (United States)

    Fu, Jianxin; Yang, Liwen; Dai, Silan

    2014-07-01

    In Arabidopsis, circadian clock genes play important roles in photoperiod pathway by regulating the daytime expression of CONSTANS (CO), but related reports for chrysanthemum are notably limited. In this study, we isolated eleven circadian clock genes, which lie in the three interconnected negative and positive feedback loops in a wild diploid chrysanthemum, Chrysanthemum lavandulifolium. With the exception of ClELF3, ClPRR1 and ClPRR73, most of the circadian clock genes are expressed more highly in leaves than in other tested tissues. The diurnal rhythms of these circadian clock genes are similar to those of their homologs in Arabidopsis. ClELF3 and ClZTL are constitutively expressed at all time points in both assessed photoperiods. The expression succession from morning to night of the PSEUDO RESPONSE REGULATOR (PRR) gene family occurs in the order ClPRR73/ClPRR37, ClPRR5, and then ClPRR1. ClLHY is expressed during the dawn period, and ClGIs is expressed during the dusk period. The peak expression levels of ClFKF1 and ClGIs are synchronous in the inductive photoperiod. However, in the non-inductive night break (NB) condition or non-24 h photoperiod, the peak expression level of ClFKF1 is significantly changed, indicating that ClFKF1 itself or the synchronous expression of ClFKF1 and ClGIs might be essential to initiate the flowering of C. lavandulifolium. This study provides the first extensive evaluation of circadian clock genes, and it presents a useful foundation for dissecting the functions of circadian clock genes in C. lavandulifolium. Copyright © 2014. Published by Elsevier Masson SAS.

  19. Ras-mediated deregulation of the circadian clock in cancer.

    Directory of Open Access Journals (Sweden)

    Angela Relógio

    Full Text Available Circadian rhythms are essential to the temporal regulation of molecular processes in living systems and as such to life itself. Deregulation of these rhythms leads to failures in biological processes and eventually to the manifestation of pathological phenotypes including cancer. To address the questions as to what are the elicitors of a disrupted clock in cancer, we applied a systems biology approach to correlate experimental, bioinformatics and modelling data from several cell line models for colorectal and skin cancer. We found strong and weak circadian oscillators within the same type of cancer and identified a set of genes, which allows the discrimination between the two oscillator-types. Among those genes are IFNGR2, PITX2, RFWD2, PPARγ, LOXL2, Rab6 and SPARC, all involved in cancer-related pathways. Using a bioinformatics approach, we extended the core-clock network and present its interconnection to the discriminative set of genes. Interestingly, such gene signatures link the clock to oncogenic pathways like the RAS/MAPK pathway. To investigate the potential impact of the RAS/MAPK pathway - a major driver of colorectal carcinogenesis - on the circadian clock, we used a computational model which predicted that perturbation of BMAL1-mediated transcription can generate the circadian phenotypes similar to those observed in metastatic cell lines. Using an inducible RAS expression system, we show that overexpression of RAS disrupts the circadian clock and leads to an increase of the circadian period while RAS inhibition causes a shortening of period length, as predicted by our mathematical simulations. Together, our data demonstrate that perturbations induced by a single oncogene are sufficient to deregulate the mammalian circadian clock.

  20. Ras-Mediated Deregulation of the Circadian Clock in Cancer

    Science.gov (United States)

    Relógio, Angela; Thomas, Philippe; Medina-Pérez, Paula; Reischl, Silke; Bervoets, Sander; Gloc, Ewa; Riemer, Pamela; Mang-Fatehi, Shila; Maier, Bert; Schäfer, Reinhold; Leser, Ulf; Herzel, Hanspeter; Kramer, Achim; Sers, Christine

    2014-01-01

    Circadian rhythms are essential to the temporal regulation of molecular processes in living systems and as such to life itself. Deregulation of these rhythms leads to failures in biological processes and eventually to the manifestation of pathological phenotypes including cancer. To address the questions as to what are the elicitors of a disrupted clock in cancer, we applied a systems biology approach to correlate experimental, bioinformatics and modelling data from several cell line models for colorectal and skin cancer. We found strong and weak circadian oscillators within the same type of cancer and identified a set of genes, which allows the discrimination between the two oscillator-types. Among those genes are IFNGR2, PITX2, RFWD2, PPARγ, LOXL2, Rab6 and SPARC, all involved in cancer-related pathways. Using a bioinformatics approach, we extended the core-clock network and present its interconnection to the discriminative set of genes. Interestingly, such gene signatures link the clock to oncogenic pathways like the RAS/MAPK pathway. To investigate the potential impact of the RAS/MAPK pathway - a major driver of colorectal carcinogenesis - on the circadian clock, we used a computational model which predicted that perturbation of BMAL1-mediated transcription can generate the circadian phenotypes similar to those observed in metastatic cell lines. Using an inducible RAS expression system, we show that overexpression of RAS disrupts the circadian clock and leads to an increase of the circadian period while RAS inhibition causes a shortening of period length, as predicted by our mathematical simulations. Together, our data demonstrate that perturbations induced by a single oncogene are sufficient to deregulate the mammalian circadian clock. PMID:24875049