Ferroelectric switch for a high-power Ka-band active pulse compressor

Energy Technology Data Exchange (ETDEWEB)

Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT (United States)

2013-12-18

Results are presented for design of a high-power microwave switch for operation at 34.3 GHz, intended for use in an active RF pulse compressor. The active element in the switch is a ring of ferroelectric material, whose dielectric constant can be rapidly changed by application of a high-voltage pulse. As envisioned, two of these switches would be built into a pair of delay lines, as in SLED-II at SLAC, so as to allow 30-MW μs-length Ka-band pulses to be compressed in time by a factor-of-9 and multiplied in amplitude to generate 200 MW peak power pulses. Such high-power pulses could be used for testing and evaluation of high-gradient mm-wave accelerator structures, for example. Evaluation of the switch design was carried out with an X-band (11.43 GHz) prototype, built to incorporate all the features required for the Ka-band version.

Active Radiative Thermal Switching with Graphene Plasmon Resonators.

Science.gov (United States)

Ilic, Ognjen; Thomas, Nathan H; Christensen, Thomas; Sherrott, Michelle C; Soljačić, Marin; Minnich, Austin J; Miller, Owen D; Atwater, Harry A

2018-03-27

We theoretically demonstrate a near-field radiative thermal switch based on thermally excited surface plasmons in graphene resonators. The high tunability of graphene enables substantial modulation of near-field radiative heat transfer, which, when combined with the use of resonant structures, overcomes the intrinsically broadband nature of thermal radiation. In canonical geometries, we use nonlinear optimization to show that stacked graphene sheets offer improved heat conductance contrast between "ON" and "OFF" switching states and that a >10× higher modulation is achieved between isolated graphene resonators than for parallel graphene sheets. In all cases, we find that carrier mobility is a crucial parameter for the performance of a radiative thermal switch. Furthermore, we derive shape-agnostic analytical approximations for the resonant heat transfer that provide general scaling laws and allow for direct comparison between different resonator geometries dominated by a single mode. The presented scheme is relevant for active thermal management and energy harvesting as well as probing excited-state dynamics at the nanoscale.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

KAUST Repository

Bouchaala, Adam M.; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I.

2016-01-01

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

KAUST Repository

Bouchaala, Adam M.

2016-05-25

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection.

Science.gov (United States)

Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I

2016-05-25

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

Hessian-regularized co-training for social activity recognition.

Science.gov (United States)

Liu, Weifeng; Li, Yang; Lin, Xu; Tao, Dacheng; Wang, Yanjiang

2014-01-01

Co-training is a major multi-view learning paradigm that alternately trains two classifiers on two distinct views and maximizes the mutual agreement on the two-view unlabeled data. Traditional co-training algorithms usually train a learner on each view separately and then force the learners to be consistent across views. Although many co-trainings have been developed, it is quite possible that a learner will receive erroneous labels for unlabeled data when the other learner has only mediocre accuracy. This usually happens in the first rounds of co-training, when there are only a few labeled examples. As a result, co-training algorithms often have unstable performance. In this paper, Hessian-regularized co-training is proposed to overcome these limitations. Specifically, each Hessian is obtained from a particular view of examples; Hessian regularization is then integrated into the learner training process of each view by penalizing the regression function along the potential manifold. Hessian can properly exploit the local structure of the underlying data manifold. Hessian regularization significantly boosts the generalizability of a classifier, especially when there are a small number of labeled examples and a large number of unlabeled examples. To evaluate the proposed method, extensive experiments were conducted on the unstructured social activity attribute (USAA) dataset for social activity recognition. Our results demonstrate that the proposed method outperforms baseline methods, including the traditional co-training and LapCo algorithms.

Hessian-regularized co-training for social activity recognition.

Directory of Open Access Journals (Sweden)

Weifeng Liu

Full Text Available Co-training is a major multi-view learning paradigm that alternately trains two classifiers on two distinct views and maximizes the mutual agreement on the two-view unlabeled data. Traditional co-training algorithms usually train a learner on each view separately and then force the learners to be consistent across views. Although many co-trainings have been developed, it is quite possible that a learner will receive erroneous labels for unlabeled data when the other learner has only mediocre accuracy. This usually happens in the first rounds of co-training, when there are only a few labeled examples. As a result, co-training algorithms often have unstable performance. In this paper, Hessian-regularized co-training is proposed to overcome these limitations. Specifically, each Hessian is obtained from a particular view of examples; Hessian regularization is then integrated into the learner training process of each view by penalizing the regression function along the potential manifold. Hessian can properly exploit the local structure of the underlying data manifold. Hessian regularization significantly boosts the generalizability of a classifier, especially when there are a small number of labeled examples and a large number of unlabeled examples. To evaluate the proposed method, extensive experiments were conducted on the unstructured social activity attribute (USAA dataset for social activity recognition. Our results demonstrate that the proposed method outperforms baseline methods, including the traditional co-training and LapCo algorithms.

Ion channel density regulates switches between regular and fast spiking in soma but not in axons.

Directory of Open Access Journals (Sweden)

Hugo Zeberg

2010-04-01

Full Text Available The threshold firing frequency of a neuron is a characterizing feature of its dynamical behaviour, in turn determining its role in the oscillatory activity of the brain. Two main types of dynamics have been identified in brain neurons. Type 1 dynamics (regular spiking shows a continuous relationship between frequency and stimulation current (f-I(stim and, thus, an arbitrarily low frequency at threshold current; Type 2 (fast spiking shows a discontinuous f-I(stim relationship and a minimum threshold frequency. In a previous study of a hippocampal neuron model, we demonstrated that its dynamics could be of both Type 1 and Type 2, depending on ion channel density. In the present study we analyse the effect of varying channel density on threshold firing frequency on two well-studied axon membranes, namely the frog myelinated axon and the squid giant axon. Moreover, we analyse the hippocampal neuron model in more detail. The models are all based on voltage-clamp studies, thus comprising experimentally measurable parameters. The choice of analysing effects of channel density modifications is due to their physiological and pharmacological relevance. We show, using bifurcation analysis, that both axon models display exclusively Type 2 dynamics, independently of ion channel density. Nevertheless, both models have a region in the channel-density plane characterized by an N-shaped steady-state current-voltage relationship (a prerequisite for Type 1 dynamics and associated with this type of dynamics in the hippocampal model. In summary, our results suggest that the hippocampal soma and the two axon membranes represent two distinct kinds of membranes; membranes with a channel-density dependent switching between Type 1 and 2 dynamics, and membranes with a channel-density independent dynamics. The difference between the two membrane types suggests functional differences, compatible with a more flexible role of the soma membrane than that of the axon membrane.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

Directory of Open Access Journals (Sweden)

Adam Bouchaala

2016-05-01

Full Text Available The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF, namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

Science.gov (United States)

Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I.

2016-01-01

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming. PMID:27231914

Working memory and the control of action: evidence from task switching.

Science.gov (United States)

Baddeley, A; Chincotta, D; Adlam, A

2001-12-01

A series of 7 experiments used dual-task methodology to investigate the role of working memory in the operation of a simple action-control plan or program involving regular switching between addition and subtraction. Lists requiring switching were slower than blocked lists and showed 2 concurrent task effects. Demanding executive tasks impaired performance on both blocked and switched lists, whereas articulatory suppression impaired principally the switched condition. Implications for models of task switching and working memory and for the Vygotskian concept of verbal control of action are discussed.

Quitting activity and tobacco brand switching: findings from the ITC-4 Country Survey.

Science.gov (United States)

Cowie, Genevieve A; Swift, Elena; Partos, Timea; Borland, Ron

2015-04-01

Among Australian smokers, to examine associations between cigarette brand switching, quitting activity and possible causal directions by lagging the relationships in different directions. Current smokers from nine waves (2002 to early 2012) of the ITC-4 Country Survey Australian dataset were surveyed. Measures were brand switching, both brand family and product type (roll-your-own versus factory-made cigarettes) reported in adjacent waves, interest in quitting, recent quit attempts, and one month sustained abstinence. Switching at one interval was unrelated to concurrent quit interest. Quit interest predicted switching at the following interval, but the effect disappeared once subsequent quit attempts were controlled for. Recent quit attempts more strongly predicted switching at concurrent (OR 1.34, 95%CI=1.18-1.52, pbrand switching does not affect subsequent quitting. Brand switching does not appear to interfere with quitting. © 2015 Public Health Association of Australia.

Validation of mercury tip-switch and accelerometer activity sensors for identifying resting and active behavior in bears

Science.gov (United States)

Jasmine Ware,; Rode, Karyn D.; Pagano, Anthony M.; Bromaghin, Jeffrey F.; Robbins, Charles T.; Joy Erlenbach,; Shannon Jensen,; Amy Cutting,; Nicole Nicassio-Hiskey,; Amy Hash,; Owen, Megan A.; Heiko Jansen,

2015-01-01

Activity sensors are often included in wildlife transmitters and can provide information on the behavior and activity patterns of animals remotely. However, interpreting activity-sensor data relative to animal behavior can be difficult if animals cannot be continuously observed. In this study, we examined the performance of a mercury tip-switch and a tri-axial accelerometer housed in collars to determine whether sensor data can be accurately classified as resting and active behaviors and whether data are comparable for the 2 sensor types. Five captive bears (3 polar [Ursus maritimus] and 2 brown [U. arctos horribilis]) were fitted with a collar specially designed to internally house the sensors. The bears’ behaviors were recorded, classified, and then compared with sensor readings. A separate tri-axial accelerometer that sampled continuously at a higher frequency and provided raw acceleration values from 3 axes was also mounted on the collar to compare with the lower resolution sensors. Both accelerometers more accurately identified resting and active behaviors at time intervals ranging from 1 minute to 1 hour (≥91.1% accuracy) compared with the mercury tip-switch (range = 75.5–86.3%). However, mercury tip-switch accuracy improved when sampled at longer intervals (e.g., 30–60 min). Data from the lower resolution accelerometer, but not the mercury tip-switch, accurately predicted the percentage of time spent resting during an hour. Although the number of bears available for this study was small, our results suggest that these activity sensors can remotely identify resting versus active behaviors across most time intervals. We recommend that investigators consider both study objectives and the variation in accuracy of classifying resting and active behaviors reported here when determining sampling interval.

Studies of ZVS soft switching of dual-active-bridge isolated bidirectional DC-DC converters

Science.gov (United States)

Xu, Fei; Zhao, Feng; Shi, Qibiao; Wen, Xuhui

2018-05-01

To operate dual-active-bridge isolated bidirectional dc- dc converter (DAB) at high efficiency, the two bridge switches must operate with Zero-Voltage-Switching (ZVS) over as wide an operating range as possible. This paper proposes a new perspective on realizing ZVS in dead-time. An exact theoretical analysis and mathematical mode is built to explain the process of ZVS switching in dead-time under Single Phase Shift (SPS) control strategy. In order to assure the two bridge switches operate on soft switching, every SPS switching point is analyzed. Generally, dead-time will be determined when the power electronic devices is selected. The key factor to realizing ZVS is the size of the end time of resonance comparing to dead-time. Through detailed analysis, it can obtain the conditions of all switches achieving ZVS turn-on and turn-off. Finally, simulation validates the theoretical analysis and some advice are given to realize the ZVS soft switching.

The double switch for atrioventricular discordance.

Science.gov (United States)

Brawn, William J

2005-01-01

Conventional surgery for atrioventricular discordance usually associated with ventricular arterial discordance leaves the morphologic right ventricle in the systemic circulation. Long-term follow-up results with this approach reveal a high incidence of right ventricular failure. The double switch procedure was introduced to restore the morphologic left ventricle to the systemic circulation. This operation is performed in two main ways: the atrial-arterial switch and the atrial switch plus Rastelli procedure. This double switch approach has been successful at least in the medium term in abolishing morphologic right ventricular failure and its associated tricuspid valve regurgitation. In the atrial-arterial switch group, there is an incidence of morphologic left ventricular dysfunction, sometimes associated with neoaortic valve regurgitation, and the minority of cases need aortic valve replacement. The long-term function of the morphologic left ventricle and the aortic valve need careful surveillance in the future. The atrial-Rastelli group of patients has not in the medium term shown evidence of ventricular dysfunction but will require change on a regular basis of their ventricular to pulmonary artery valved conduits.

Optimization of end-pumped, actively Q-switched quasi-III-level lasers.

Science.gov (United States)

Jabczynski, Jan K; Gorajek, Lukasz; Kwiatkowski, Jacek; Kaskow, Mateusz; Zendzian, Waldemar

2011-08-15

The new model of end-pumped quasi-III-level laser considering transient pumping processes, ground-state-depletion and up-conversion effects was developed. The model consists of two parts: pumping stage and Q-switched part, which can be separated in a case of active Q-switching regime. For pumping stage the semi-analytical model was developed, enabling the calculations for final occupation of upper laser level for given pump power and duration, spatial profile of pump beam, length and dopant level of gain medium. For quasi-stationary inversion, the optimization procedure of Q-switching regime based on Lagrange multiplier technique was developed. The new approach for optimization of CW regime of quasi-three-level lasers was developed to optimize the Q-switched lasers operating with high repetition rates. Both methods of optimizations enable calculation of optimal absorbance of gain medium and output losses for given pump rate. © 2011 Optical Society of America

Adaptive Active Noise Suppression Using Multiple Model Switching Strategy

Directory of Open Access Journals (Sweden)

Quanzhen Huang

2017-01-01

Full Text Available Active noise suppression for applications where the system response varies with time is a difficult problem. The computation burden for the existing control algorithms with online identification is heavy and easy to cause control system instability. A new active noise control algorithm is proposed in this paper by employing multiple model switching strategy for secondary path varying. The computation is significantly reduced. Firstly, a noise control system modeling method is proposed for duct-like applications. Then a multiple model adaptive control algorithm is proposed with a new multiple model switching strategy based on filter-u least mean square (FULMS algorithm. Finally, the proposed algorithm was implemented on Texas Instruments digital signal processor (DSP TMS320F28335 and real time experiments were done to test the proposed algorithm and FULMS algorithm with online identification. Experimental verification tests show that the proposed algorithm is effective with good noise suppression performance.

Laser activated superconducting switch

International Nuclear Information System (INIS)

Wolf, A.A.

1976-01-01

A superconducting switch or bistable device is described consisting of a superconductor in a cryogen maintaining a temperature just below the transition temperature, having a window of the proper optical frequency band for passing a laser beam which may impinge on the superconductor when desired. The frequency of the laser is equal to or greater than the optical absorption frequency of the superconducting material and is consistent with the ratio of the gap energy of the switch material to Planck's constant, to cause depairing of electrons, and thereby normalize the superconductor. Some embodiments comprise first and second superconducting metals. Other embodiments feature the two superconducting metals separated by a thin film insulator through which the superconducting electrons tunnel during superconductivity

Antecedent occipital alpha band activity predicts the impact of oculomotor events in perceptual switching

Directory of Open Access Journals (Sweden)

Hironori eNakatani

2013-05-01

Full Text Available Oculomotor events such as blinks and saccades transiently interrupt the visual input and, even though this mostly goes undetected, these brief interruptions could still influence the percept. In particular, both blinking and saccades facilitate switching in ambiguous figures such as the Necker cube. To investigate the neural state antecedent to these oculomotor events during the perception of an ambiguous figure, we measured the human scalp electroencephalogram (EEG. When blinking led to perceptual switching, antecedent occipital alpha band activity exhibited a transient increase in amplitude. When a saccade led to switching, a series of transient increases and decreases in amplitude was observed in the antecedent occipital alpha band activity. Our results suggest that the state of occipital alpha band activity predicts the impact of oculomotor events on the percept.

Double-stranded endonuclease activity in Bacillus halodurans clustered regularly interspaced short palindromic repeats (CRISPR)-associated Cas2 protein.

Science.gov (United States)

Nam, Ki Hyun; Ding, Fran; Haitjema, Charles; Huang, Qingqiu; DeLisa, Matthew P; Ke, Ailong

2012-10-19

The CRISPR (clustered regularly interspaced short palindromic repeats) system is a prokaryotic RNA-based adaptive immune system against extrachromosomal genetic elements. Cas2 is a universally conserved core CRISPR-associated protein required for the acquisition of new spacers for CRISPR adaptation. It was previously characterized as an endoribonuclease with preference for single-stranded (ss)RNA. Here, we show using crystallography, mutagenesis, and isothermal titration calorimetry that the Bacillus halodurans Cas2 (Bha_Cas2) from the subtype I-C/Dvulg CRISPR instead possesses metal-dependent endonuclease activity against double-stranded (ds)DNA. This activity is consistent with its putative function in producing new spacers for insertion into the 5'-end of the CRISPR locus. Mutagenesis and isothermal titration calorimetry studies revealed that a single divalent metal ion (Mg(2+) or Mn(2+)), coordinated by a symmetric Asp pair in the Bha_Cas2 dimer, is involved in the catalysis. We envision that a pH-dependent conformational change switches Cas2 into a metal-binding competent conformation for catalysis. We further propose that the distinct substrate preferences among Cas2 proteins may be determined by the sequence and structure in the β1-α1 loop.

Optical Switching for Dynamic Distribution of Wireless-Over-Fiber Signals in Active Optical Networks

DEFF Research Database (Denmark)

Vegas Olmos, Juan José; Rodes, Guillermo; Tafur Monroy, Idelfonso

2012-01-01

In this paper, we report on an experimental validation of dynamic distribution of wireless-over-fiber by employing optical switching using semiconductor optical amplifiers; we also provide a channel distribution scheme and a generic topology for such an optical switch. The experiment consists...... of a four wavelength-division-multiplexed channel system operating on a WiMax frequency band and employing an orthogonal-frequency-division-multiplexing modulation at 625 Mbits/s per channel, transmission of the data over 20 km of optical fiber, and active switching in a 1 × 16 active optical switch....... The results show a negligible power penalty on each channel for both the best and the worst case in terms of inter-channel crosstalk. The presented system is highly scalable both in terms of port count and throughput, a desirable feature in highly branched access networks, and is modulation- and frequency...

Intentional preparation of auditory attention-switches: Explicit cueing and sequential switch-predictability.

Science.gov (United States)

Seibold, Julia C; Nolden, Sophie; Oberem, Josefa; Fels, Janina; Koch, Iring

2018-06-01

In an auditory attention-switching paradigm, participants heard two simultaneously spoken number-words, each presented to one ear, and decided whether the target number was smaller or larger than 5 by pressing a left or right key. An instructional cue in each trial indicated which feature had to be used to identify the target number (e.g., female voice). Auditory attention-switch costs were found when this feature changed compared to when it repeated in two consecutive trials. Earlier studies employing this paradigm showed mixed results when they examined whether such cued auditory attention-switches can be prepared actively during the cue-stimulus interval. This study systematically assessed which preconditions are necessary for the advance preparation of auditory attention-switches. Three experiments were conducted that controlled for cue-repetition benefits, modality switches between cue and stimuli, as well as for predictability of the switch-sequence. Only in the third experiment, in which predictability for an attention-switch was maximal due to a pre-instructed switch-sequence and predictable stimulus onsets, active switch-specific preparation was found. These results suggest that the cognitive system can prepare auditory attention-switches, and this preparation seems to be triggered primarily by the memorised switching-sequence and valid expectations about the time of target onset.

A new Zero-Voltage-Transition PWM switching cell

Energy Technology Data Exchange (ETDEWEB)

Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

1997-12-31

In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.

Survival and failure modes: platform-switching for internal and external hexagon cemented fixed dental prostheses.

Science.gov (United States)

Anchieta, Rodolfo B; Machado, Lucas S; Hirata, Ronaldo; Coelho, Paulo G; Bonfante, Estevam A

2016-10-01

This study evaluated the probability of survival (reliability) of platform-switched fixed dental prostheses (FDPs) cemented on different implant-abutment connection designs. Eighty-four-three-unit FDPs (molar pontic) were cemented on abutments connected to two implants of external or internal hexagon connection. Four groups (n = 21 each) were established: external hexagon connection and regular platform (ERC); external hexagon connection and switched platform (ESC); internal hexagon and regular platform (IRC); and internal hexagon and switched platform (ISC). Prostheses were subjected to step-stress accelerated life testing in water. Weibull curves and probability of survival for a mission of 100,000 cycles at 400 N (two-sided 90% CI) were calculated. The beta values of 0.22, 0.48, 0.50, and 1.25 for groups ERC, ESC, IRC, and ISC, respectively, indicated a limited role of fatigue in damage accumulation, except for group ISC. Survival decreased for both platform-switched groups (ESC: 74%, and ISC: 59%) compared with the regular matching platform counterparts (ERC: 95%, and IRC: 98%). Characteristic strength was higher only for ERC compared with ESC, but not different between internal connections. Failures chiefly involved the abutment screw. Platform switching decreased the probability of survival of FDPs on both external and internal connections. The absence in loss of characteristic strength observed in internal hexagon connections favor their use compared with platform-switched external hexagon connections. © 2016 Eur J Oral Sci.

An Active Trap Filter for Switching Harmonics Attenuation of Low-Pulse-Ratio Inverters

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang

2017-01-01

method has also been proposed for the ATF to better enforce its active switching harmonic bypassing ability. Compared with conventional schemes for controlling active power filters, the proposed method is more readily implemented, since it requires neither current reference generation nor high......-bandwidth current control loop. Moreover, the use of a series LC-filter at its ac-side helps the ATF to reduce its inverter voltage and power ratings. Compensated frequency range of the ATF can hence be enlarged by using a comparably higher switching frequency and a proper step-by-step design procedure...

Scalable Active Optical Access Network Using Variable High-Speed PLZT Optical Switch/Splitter

Science.gov (United States)

Ashizawa, Kunitaka; Sato, Takehiro; Tokuhashi, Kazumasa; Ishii, Daisuke; Okamoto, Satoru; Yamanaka, Naoaki; Oki, Eiji

This paper proposes a scalable active optical access network using high-speed Plumbum Lanthanum Zirconate Titanate (PLZT) optical switch/splitter. The Active Optical Network, called ActiON, using PLZT switching technology has been presented to increase the number of subscribers and the maximum transmission distance, compared to the Passive Optical Network (PON). ActiON supports the multicast slot allocation realized by running the PLZT switch elements in the splitter mode, which forces the switch to behave as an optical splitter. However, the previous ActiON creates a tradeoff between the network scalability and the power loss experienced by the optical signal to each user. It does not use the optical power efficiently because the optical power is simply divided into 0.5 to 0.5 without considering transmission distance from OLT to each ONU. The proposed network adopts PLZT switch elements in the variable splitter mode, which controls the split ratio of the optical power considering the transmission distance from OLT to each ONU, in addition to PLZT switch elements in existing two modes, the switching mode and the splitter mode. The proposed network introduces the flexible multicast slot allocation according to the transmission distance from OLT to each user and the number of required users using three modes, while keeping the advantages of ActiON, which are to support scalable and secure access services. Numerical results show that the proposed network dramatically reduces the required number of slots and supports high bandwidth efficiency services and extends the coverage of access network, compared to the previous ActiON, and the required computation time for selecting multicast users is less than 30msec, which is acceptable for on-demand broadcast services.

Parasitic resistive switching uncovered from complementary resistive switching in single active-layer oxide memory device

Science.gov (United States)

Zhu, Lisha; Hu, Wei; Gao, Chao; Guo, Yongcai

2017-12-01

This paper reports the reversible transition processes between the bipolar and complementary resistive switching (CRS) characteristics on the binary metal-oxide resistive memory devices of Pt/HfO x /TiN and Pt/TaO x /TiN by applying the appropriate bias voltages. More interestingly, by controlling the amplitude of the negative bias, the parasitic resistive switching effect exhibiting repeatable switching behavior is uncovered from the CRS behavior. The electrical observation of the parasitic resistive switching effect can be explained by the controlled size of the conductive filament. This work confirms the transformation and interrelationship among the bipolar, parasitic, and CRS effects, and thus provides new insight into the understanding of the physical mechanism of the binary metal-oxide resistive switching memory devices.

Optimal control of switching time in switched stochastic systems with multi-switching times and different costs

Science.gov (United States)

Liu, Xiaomei; Li, Shengtao; Zhang, Kanjian

2017-08-01

In this paper, we solve an optimal control problem for a class of time-invariant switched stochastic systems with multi-switching times, where the objective is to minimise a cost functional with different costs defined on the states. In particular, we focus on problems in which a pre-specified sequence of active subsystems is given and the switching times are the only control variables. Based on the calculus of variation, we derive the gradient of the cost functional with respect to the switching times on an especially simple form, which can be directly used in gradient descent algorithms to locate the optimal switching instants. Finally, a numerical example is given, highlighting the validity of the proposed methodology.

Psychological Benefits of Regular Physical Activity: Evidence from Emerging Adults

Science.gov (United States)

Cekin, Resul

2015-01-01

Emerging adulthood is a transitional stage between late adolescence and young adulthood in life-span development that requires significant changes in people's lives. Therefore, identifying protective factors for this population is crucial. This study investigated the effects of regular physical activity on self-esteem, optimism, and happiness in…

A new Zero-Current-Transition PWM switching cell

Energy Technology Data Exchange (ETDEWEB)

Grigore, V. [Electronics and Telecommunications Faculty, `Politechnica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

1997-12-31

In this paper a new Zero-Current-Transition (ZCT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus as auxiliary circuit. The auxiliary circuit is inactive during the ON ad OFF intervals of the switches in the normal PWM switch. The transitions between the two states are controlled by the auxiliary circuit. Prior to turn-off, the current through the active switch in the PWM cell is forced to zero, thus the turn-off losses of the active switch are practically eliminated. At turn-on the auxiliary circuit slows down the growing rate of the current through the main switch. Thus, turn-on losses are also very much reduced. The active switch operates under ZCT conditions, the passive switch (diode) has a controlled reverse recovery, while the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 3 refs.

Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.; Andersen, Michael A.E.

2005-07-01

This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify design, increase efficiency and integration level, reduce product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented. (au)

Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

DEFF Research Database (Denmark)

Ljusev, Petar; Andersen, Michael Andreas E.

2005-01-01

This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify the design, increase...... efficiency, reduce the product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented....

Activator Protein-1: redox switch controlling structure and DNA-binding.

Science.gov (United States)

Yin, Zhou; Machius, Mischa; Nestler, Eric J; Rudenko, Gabby

2017-11-02

The transcription factor, activator protein-1 (AP-1), binds to cognate DNA under redox control; yet, the underlying mechanism has remained enigmatic. A series of crystal structures of the AP-1 FosB/JunD bZIP domains reveal ordered DNA-binding regions in both FosB and JunD even in absence DNA. However, while JunD is competent to bind DNA, the FosB bZIP domain must undergo a large conformational rearrangement that is controlled by a 'redox switch' centered on an inter-molecular disulfide bond. Solution studies confirm that FosB/JunD cannot undergo structural transition and bind DNA when the redox-switch is in the 'OFF' state, and show that the mid-point redox potential of the redox switch affords it sensitivity to cellular redox homeostasis. The molecular and structural studies presented here thus reveal the mechanism underlying redox-regulation of AP-1 Fos/Jun transcription factors and provide structural insight for therapeutic interventions targeting AP-1 proteins. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Manifold Regularized Experimental Design for Active Learning.

Science.gov (United States)

Zhang, Lining; Shum, Hubert P H; Shao, Ling

2016-12-02

Various machine learning and data mining tasks in classification require abundant data samples to be labeled for training. Conventional active learning methods aim at labeling the most informative samples for alleviating the labor of the user. Many previous studies in active learning select one sample after another in a greedy manner. However, this is not very effective because the classification models has to be retrained for each newly labeled sample. Moreover, many popular active learning approaches utilize the most uncertain samples by leveraging the classification hyperplane of the classifier, which is not appropriate since the classification hyperplane is inaccurate when the training data are small-sized. The problem of insufficient training data in real-world systems limits the potential applications of these approaches. This paper presents a novel method of active learning called manifold regularized experimental design (MRED), which can label multiple informative samples at one time for training. In addition, MRED gives an explicit geometric explanation for the selected samples to be labeled by the user. Different from existing active learning methods, our method avoids the intrinsic problems caused by insufficiently labeled samples in real-world applications. Various experiments on synthetic datasets, the Yale face database and the Corel image database have been carried out to show how MRED outperforms existing methods.

Dependence of regular background noise of VLF radiation and thunder-storm activity on solar wind proton density

International Nuclear Information System (INIS)

Sobolev, A.V.; Kozlov, V.I.

1997-01-01

Correlation of the intensity of slowly changing regular background noise within 9.7 kHz frequency in Yakutsk (L = 3) and of the solar wind density protons was determined. This result explains the reverse dependence of the intensity of the regular background noise on the solar activity, 27-day frequency, increase before and following geomagnetic storms, absence of relation with K p index of geomagnetic activity. Conclusion is made that growth of density of the solar wind protons results in increase of the regular background noise and thunderstorm activity

Cospectral Graphs and Regular Orthogonal Matrices of Level 2

NARCIS (Netherlands)

Abiad Monge, A.; Haemers, W.H.

2012-01-01

Abstract: For a graph Γ with adjacency matrix A, we consider a switching operation that takes Γ into a graph Γ' with adjacency matrix A', defined by A' = QtAQ, where Q is a regular orthogonal matrix of level 2 (that is, QtQ = I, Q1 = 1, 2Q is integral, and Q is not a permutation matrix). If such an

Cospectral graphs and regular orthogonal matrices of level 2

NARCIS (Netherlands)

Abiad Monge, A.; Haemers, W.H.

2012-01-01

For a graph Γ with adjacency matrix A , we consider a switching operation that takes Γ into a graph Γ′ with adjacency matrix A′ , defined by A′ = Q⊤AQ , where Q is a regular orthogonal matrix of level 2 (that is, Q⊤Q=I , Q1 = 1, 2Q is integral, and Q is not a permutation matrix). If such an

Respiratory infections and pneumonia: potential benefits of switching from smoking to vaping.

Science.gov (United States)

Campagna, Davide; Amaradio, Maria Domenica; Sands, Mark F; Polosa, Riccardo

2016-01-01

Abstaining from tobacco smoking is likely to lower the risk of respiratory infections and pneumonia. Unfortunately, quitting smoking is not easy. Electronic cigarettes (ECs) are emerging as an attractive long-term alternative nicotine source to conventional cigarettes and are being adopted by smokers who wish to reduce or quit cigarette consumption. Also, given that the propylene glycol in EC aerosols is a potent bactericidal agent, switching from smoking to regular vaping is likely to produce additional lung health benefits. Here, we critically address some of the concerns arising from regular EC use in relation to lung health, including respiratory infections and pneumonia. In conclusion, smokers who quit by switching to regular ECs use can reduce risk and reverse harm from tobacco smoking. Innovation in the e-vapour category is likely not only to further minimise residual health risks, but also to maximise health benefits.

Physiological Aging Influence on Brain Hemodynamic Activity during Task-Switching: A fNIRS Study

Directory of Open Access Journals (Sweden)

Roberta Vasta

2018-01-01

Full Text Available Task-switching (TS paradigm is a well-known validated tool useful for exploring the neural substrates of cognitive control, in particular the activity of the lateral and medial prefrontal cortex. This work is aimed at investigating how physiological aging influences hemodynamic response during the execution of a color-shape TS paradigm. A multi-channel near infrared spectroscopy (fNIRS was used to measure hemodynamic activity in 27 young (30.00 ± 7.90 years and 11 elderly participants (57.18 ± 9.29 years healthy volunteers (55% male, age range: (19–69 years during the execution of a TS paradigm. Two holders were placed symmetrically over the left/right hemispheres to record cortical activity [oxy-(HbO and deoxy-hemoglobin (HbR concentration] of the dorso-lateral prefrontal cortex (DLPFC, the dorsal premotor cortex (PMC, and the dorso-medial part of the superior frontal gyrus (sFG. TS paradigm requires participants to repeat the same task over a variable number of trials, and then to switch to a different task during the trial sequence. A two-sample t-test was carried out to detect differences in cortical responses between groups. Multiple linear regression analysis was used to evaluate the impact of age on the prefrontal neural activity. Elderly participants were significantly slower than young participants in both color- (p < 0.01, t = −3.67 and shape-single tasks (p = 0.026, t = −2.54 as well as switching (p = 0.026, t = −2.41 and repetition trials (p = 0.012, t = −2.80. Differences in cortical activation between groups were revealed for HbO mean concentration of switching task in the PMC (p = 0.048, t = 2.94. In the whole group, significant increases of behavioral performance were detected in switching trials, which positively correlated with aging. Multivariate regression analysis revealed that the HbO mean concentration of switching task in the PMC (p = 0.01, β = −0.321 and of shape single-task in the sFG (p = 0.003, β = 0

Benefits of regular aerobic exercise for executive functioning in healthy populations.

Science.gov (United States)

Guiney, Hayley; Machado, Liana

2013-02-01

Research suggests that regular aerobic exercise has the potential to improve executive functioning, even in healthy populations. The purpose of this review is to elucidate which components of executive functioning benefit from such exercise in healthy populations. In light of the developmental time course of executive functions, we consider separately children, young adults, and older adults. Data to date from studies of aging provide strong evidence of exercise-linked benefits related to task switching, selective attention, inhibition of prepotent responses, and working memory capacity; furthermore, cross-sectional fitness data suggest that working memory updating could potentially benefit as well. In young adults, working memory updating is the main executive function shown to benefit from regular exercise, but cross-sectional data further suggest that task-switching and post error performance may also benefit. In children, working memory capacity has been shown to benefit, and cross-sectional data suggest potential benefits for selective attention and inhibitory control. Although more research investigating exercise-related benefits for specific components of executive functioning is clearly needed in young adults and children, when considered across the age groups, ample evidence indicates that regular engagement in aerobic exercise can provide a simple means for healthy people to optimize a range of executive functions.

Voltage- and current-activated metal–insulator transition in VO2-based electrical switches: a lifetime operation analysis

Directory of Open Access Journals (Sweden)

Aurelian Crunteanu, Julien Givernaud, Jonathan Leroy, David Mardivirin, Corinne Champeaux, Jean-Christophe Orlianges, Alain Catherinot and Pierre Blondy

2010-01-01

Full Text Available Vanadium dioxide is an intensively studied material that undergoes a temperature-induced metal–insulator phase transition accompanied by a large change in electrical resistivity. Electrical switches based on this material show promising properties in terms of speed and broadband operation. The exploration of the failure behavior and reliability of such devices is very important in view of their integration in practical electronic circuits. We performed systematic lifetime investigations of two-terminal switches based on the electrical activation of the metal–insulator transition in VO2 thin films. The devices were integrated in coplanar microwave waveguides (CPWs in series configuration. We detected the evolution of a 10 GHz microwave signal transmitted through the CPW, modulated by the activation of the VO2 switches in both voltage- and current-controlled modes. We demonstrated enhanced lifetime operation of current-controlled VO2-based switching (more than 260 million cycles without failure compared with the voltage-activated mode (breakdown at around 16 million activation cycles. The evolution of the electrical self-oscillations of a VO2-based switch induced in the current-operated mode is a subtle indicator of the material properties modification and can be used to monitor its behavior under various external stresses in sensor applications.

Regularity effect in prospective memory during aging

Directory of Open Access Journals (Sweden)

Geoffrey Blondelle

2016-10-01

Full Text Available Background: Regularity effect can affect performance in prospective memory (PM, but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults. Objective and design: Our study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30, 16 intermediate adults (40–55, and 25 older adults (65–80. The task, adapted from the Virtual Week, was designed to manipulate the regularity of the various activities of daily life that were to be recalled (regular repeated activities vs. irregular non-repeated activities. We examine the role of several cognitive functions including certain dimensions of executive functions (planning, inhibition, shifting, and binding, short-term memory, and retrospective episodic memory to identify those involved in PM, according to regularity and age. Results: A mixed-design ANOVA showed a main effect of task regularity and an interaction between age and regularity: an age-related difference in PM performances was found for irregular activities (older < young, but not for regular activities. All participants recalled more regular activities than irregular ones with no age effect. It appeared that recalling of regular activities only involved planning for both intermediate and older adults, while recalling of irregular ones were linked to planning, inhibition, short-term memory, binding, and retrospective episodic memory. Conclusion: Taken together, our data suggest that planning capacities seem to play a major role in remembering to perform intended actions with advancing age. Furthermore, the age-PM-paradox may be attenuated when the experimental design is adapted by implementing a familiar context through the use of activities of daily living. The clinical

A Voltage Doubler Circuit to Extend the Soft-switching Range of Dual Active Bridge Converters

DEFF Research Database (Denmark)

Qin, Zian; Shen, Yanfeng; Wang, Huai

2017-01-01

A voltage doubler circuit is realized to extend the soft-switching range of Dual Active Bridge (DAB) converters. No extra hardware is added to the DAB to form this circuit, since it is composed of the dc blocking capacitor and the low side full bridge converter, which already exist in DAB....... With the voltage doubler, the DAB converter can achieve soft switching and high efficiency when the low side dc voltage is close to 2 pu (1 pu is the high side dc voltage divided by the transformer turn ratio), which can be realized only when the low side dc voltage is close to 1 pu by using the conventional phase...... shift modulation in DAB. Thus the soft switching range is extended. The soft switching boundary conditions are derived. A map to show the soft switching or hard switching in the full load and voltage range is obtained. The feasibility and effectiveness of the proposed method is finally verified...

Switching Investigations on a SiC MOSFET in a TO-247 Package

DEFF Research Database (Denmark)

Anthon, Alexander; Hernandez Botella, Juan Carlos; Zhang, Zhe

2014-01-01

This paper deals with the switching behavior of a SiC MOSFET in a TO-247 package. Based on simulations, critical parasitic inductances in the circuit layout are analyzed and their effect on the switching losses highlighted. Especially the common source inductance, a critical parameter in a TO-247...... package, has a major influence on the switching energy. Crucial design guidelines for an improved double pulse test circuit are introduced which are used for practical investigations on the switching behavior. Switching energies of a SiC MOSFET in a TO-247 package is measured depending on varying gate...... resistance and loop inductances. With total switching energy of 340.24 μJ, the SiC MOSFET has more than six times lower switching losses than a regular Si IGBT. Implementing the SiC switches in a 3 kW T-Type inverter topology, efficiency improvements of 0.8 % are achieved and maximum efficiency of 97...

Generation of an activating Zn(2+) switch in the dopamine transporter

DEFF Research Database (Denmark)

Loland, Claus Juul; Norregaard, Lene; Litman, Thomas

2002-01-01

Binding of Zn(2+) to the endogenous Zn(2+) binding site in the human dopamine transporter leads to potent inhibition of [(3)H]dopamine uptake. Here we show that mutation of an intracellular tyrosine to alanine (Y335A) converts this inhibitory Zn(2+) switch into an activating Zn(2+) switch, allowing...... Zn(2+)-dependent activation of the transporter. The tyrosine is part of a conserved YXX Phi trafficking motif (X is any residue and Phi is a residue with a bulky hydrophobic group), but Y335A did not show alterations in surface targeting or protein kinase C-mediated internalization. Despite wild...... for several substrates was increased. However, the presence of Zn(2+) in micromolar concentrations increased the V(max) up to 24-fold and partially restored the apparent affinities. The capability of Zn(2+) to restore transport is consistent with a reversible, constitutive shift in the distribution...

Fault Tolerant Operation of ISOP Multicell Dc-Dc Converter Using Active Gate Controlled SiC Protection Switch

Directory of Open Access Journals (Sweden)

Yusuke Hayashi

2016-01-01

Full Text Available An active gate controlled semiconductor protection switch using SiC-MOSFET is proposed to achieve the fault tolerant operation of ISOP (Input Series and Output Parallel connected multicell dc-dc converter. The SiC-MOSFET with high temperature capability simplifies the configuration of the protection circuit, and its on-resistance control by the active gate controller realizes the smooth protection without the voltage and the current surges. The first laboratory prototype of the protection switch is fabricated by using a SiC-MOSFET with a high frequency buck chopper for the active gate controller. The effectiveness of the proposed protection switch is verified, taking the impact of the volume reduction into account.

Nanosecond Q-switched operation of coupled Yb and Tm fibre lasers

Energy Technology Data Exchange (ETDEWEB)

Tsang, Yuen H [Laser Photonics Research Group, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Qamar, Fadi [Laser Photonics Research Group, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); King, Terence A [Laser Photonics Research Group, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Ko, Do-Kyeong [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-Gu, Gwangju 500-712 (Korea, Republic of); Lee, Jongmin [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-Gu, Gwangju 500-712 (Korea, Republic of)

2005-05-07

A small scale coupled Yb-silica and Tm-silica fibre laser system is described with output at 1.9 {mu}m and with Q-switching using an acousto-optic modulator and also by mechanical optical modulation. The Yb-fibre laser pump source exhibited strong self-pulsation with high-intensity pulses due to stimulated Brillouin scattering. But regular Q-switched pulses were generated from the Tm-fibre laser with an energy of {approx}2.4 {mu}J and duration (FWHM) of {approx}280 ns for modulation frequencies of 1-20 kHz when using acousto-optic modulation. The main effects that limit the Q-switched pulse peak power are the onset of gain-switched pulsing during the low-Q state and strong pump excited state absorption.

Actively Q-switched laser with novel Nd:YAG/YAG polygonal active-mirror

Science.gov (United States)

Lang, Ye; Chen, Yanzhong; Ge, Wenqi; He, Jianguo; Zhang, Hongbo; Liao, Lifen; Xin, Jianguo; Zhang, Jian; Fan, Zhongwei

2018-03-01

In this work, we demonstrate an efficient actively Q-switched laser based on a novel crystal Nd:YAG/YAG polygonal active mirror. A passively cooled crystal Nd:YAG/YAG polygonal active mirror with an end pump scheme was used as the gain medium. For the overlap between the TEM00 laser mode and large gain profile, a cavity was carefully designed with a large fundamental mode volume. With a maximum absorbed power of 3.1 W, a 685 mW average output power with a pulse repetition of 5 kHz was attained, and the corresponding optical-optical and slope efficiency were 22.1% and 27.7%, respectively. The pulse width was 133.9 ns. The beam quality (M 2) was 1.561 in the horizontal direction and 1.261 in the vertical direction.

Regular physical activity reduces hospital admission and mortality in chronic obstructive pulmonary disease: a population based cohort study

DEFF Research Database (Denmark)

Garcia-Aymerich, J; Lange, Peter; Benet, M

2006-01-01

.97). Low, moderate and high levels of regular physical activity were associated with an adjusted lower risk of all-cause mortality (hazard ratio (HR) 0.76, 95% CI 0.65 to 0.90) and respiratory mortality (HR 0.70, 95% CI 0.48 to 1.02). No effect modification was found for sex, age group, COPD severity......BACKGROUND: Information about the influence of regular physical activity on the course of chronic obstructive pulmonary disease (COPD) is scarce. A study was undertaken to examine the association between regular physical activity and both hospital admissions for COPD and all-cause and specific...... mortality in COPD subjects. METHODS: From a population-based sample recruited in Copenhagen in 1981-3 and 1991-4, 2386 individuals with COPD (according to lung function tests) were identified and followed until 2000. Self-reported regular physical activity at baseline was classified into four categories...

Low Capacitive Inductors for Fast Switching Devices in Active Power Factor Correction Applications

DEFF Research Database (Denmark)

Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E.

2014-01-01

This paper examines different winding strategies for reduced capacitance inductors in active power factor correction circuits (PFC). The effect of the parasitic capacitance is analyzed from an electro magnetic compatibility (EMI) and efficiency point of views. The purpose of this work is to inves......This paper examines different winding strategies for reduced capacitance inductors in active power factor correction circuits (PFC). The effect of the parasitic capacitance is analyzed from an electro magnetic compatibility (EMI) and efficiency point of views. The purpose of this work...... is to investigate different winding approaches and identify suitable solutions for high switching frequency/high speed transition PFC designs. A low parasitic capacitance PCB based inductor design is proposed to address the challenges imposed by high switching frequency PFC Boost converters....

Global regularizing flows with topology preservation for active contours and polygons.

Science.gov (United States)

Sundaramoorthi, Ganesh; Yezzi, Anthony

2007-03-01

Active contour and active polygon models have been used widely for image segmentation. In some applications, the topology of the object(s) to be detected from an image is known a priori, despite a complex unknown geometry, and it is important that the active contour or polygon maintain the desired topology. In this work, we construct a novel geometric flow that can be added to image-based evolutions of active contours and polygons in order to preserve the topology of the initial contour or polygon. We emphasize that, unlike other methods for topology preservation, the proposed geometric flow continually adjusts the geometry of the original evolution in a gradual and graceful manner so as to prevent a topology change long before the curve or polygon becomes close to topology change. The flow also serves as a global regularity term for the evolving contour, and has smoothness properties similar to curvature flow. These properties of gradually adjusting the original flow and global regularization prevent geometrical inaccuracies common with simple discrete topology preservation schemes. The proposed topology preserving geometric flow is the gradient flow arising from an energy that is based on electrostatic principles. The evolution of a single point on the contour depends on all other points of the contour, which is different from traditional curve evolutions in the computer vision literature.

Maximal feeding with active prey-switching: A kill-the-winner functional response and its effect on global diversity and biogeography

Science.gov (United States)

Vallina, S. M.; Ward, B. A.; Dutkiewicz, S.; Follows, M. J.

2014-01-01

Predators' switching towards the most abundant prey is a mechanism that stabilizes population dynamics and helps overcome competitive exclusion of species in food webs. Current formulations of active prey-switching, however, display non-maximal feeding in which the predators' total ingestion decays exponentially with the number prey species (i.e. the diet breadth) even though the total prey biomass stays constant. We analyse three previously published multi-species functional responses which have either active switching or maximal feeding, but not both. We identify the cause of this apparent incompatibility and describe a kill-the-winner formulation that combines active switching with maximal feeding. Active switching is shown to be a community response in which some predators become prey-selective and the formulations with maximal or non-maximal feeding are implicitly assuming different food web configurations. Global simulations using a marine ecosystem model with 64 phytoplankton species belonging to 4 major functional groups show that the species richness and biogeography of phytoplankton are very sensitive to the choice of the functional response for grazing. The phytoplankton biogeography reflects the balance between the competitive abilities for nutrient uptake and the degree of apparent competition which occurs indirectly between species that share a common predator species. The phytoplankton diversity significantly increases when active switching is combined with maximal feeding through predator-mediated coexistence.

A translational research intervention to reduce screen behaviours and promote physical activity among children: Switch-2-Activity

NARCIS (Netherlands)

Salmon, J.; Jorna, M.; Hume, C.; Arundell, L.; Chahine, N.; Tienstra, M.L.; Crawford, D.

2011-01-01

Translational or implementation research that assesses the effectiveness of strategies to promote health behaviours among children that have been previously tested under 'ideal' conditions is rarely reported. Switch-2-Activity aimed to examine the effectiveness of an abbreviated programme delivered

Influence of regular proprioceptive and bioenergetic physical activities on balance control in elderly women.

Science.gov (United States)

Gauchard, Gérome C; Gangloff, Pierre; Jeandel, Claude; Perrin, Philippe P

2003-09-01

Balance disorders increase considerably with age due to a decrease in posture regulation quality, and are accompanied by a higher risk of falling. Conversely, physical activities have been shown to improve the quality of postural control in elderly individuals and decrease the number of falls. The aim of this study was to evaluate the impact of two types of exercise on the visual afferent and on the different parameters of static balance regulation. Static postural control was evaluated in 44 healthy women aged over 60 years. Among them, 15 regularly practiced proprioceptive physical activities (Group I), 12 regularly practiced bioenergetic physical activities (Group II), and 18 controls walked on a regular basis (Group III). Group I participants displayed lower sway path and area values, whereas Group III participants displayed the highest, both in eyes-open and eyes-closed conditions. Group II participants displayed intermediate values, close to those of Group I in the eyes-open condition and those of Group III in the eyes-closed condition. Visual afferent contribution was more pronounced for Group II and III participants than for Group I participants. Proprioceptive exercise appears to have the best impact on balance regulation and precision. Besides, even if bioenergetic activity improves postural control in simple postural tasks, more difficult postural tasks show that this type of activity does not develop a neurosensorial proprioceptive input threshold as well, probably on account of the higher contribution of visual afferent.

Physical Educators' Habitual Physical Activity and Self-Efficacy for Regular Exercise

Science.gov (United States)

Zhu, Xihe; Haegele, Justin A.; Davis, Summer

2018-01-01

The purpose of this study was to examine physical education teachers' habitual physical activity and self-efficacy for regular exercise. In-service physical education teachers (N = 168) voluntarily completed an online questionnaire that included items to collect demographic information (gender, race/ethnicity, years of teaching experience, and…

Interrupting Prolonged Sitting with Regular Activity Breaks does not Acutely Influence Appetite: A Randomised Controlled Trial

OpenAIRE

Evelyn M. Mete; Tracy L. Perry; Jillian J. Haszard; Ashleigh R. Homer; Stephen P. Fenemor; Nancy J. Rehrer; C. Murray Skeaff; Meredith C. Peddie

2018-01-01

Regular activity breaks increase energy expenditure; however, this may promote compensatory eating behaviour. The present study compared the effects of regular activity breaks and prolonged sitting on appetite. In a randomised, cross-over trial, 36 healthy adults (BMI (Body Mass Index) 23.9 kg/m2 (S.D. = 3.9)) completed four, two-day interventions: two with prolonged sitting (SIT), and two with sitting and 2 min of walking every 30 min (RAB). Standardized meals were provided throughout the in...

5 CFR 551.421 - Regular working hours.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Regular working hours. 551.421 Section... Activities § 551.421 Regular working hours. (a) Under the Act there is no requirement that a Federal employee... distinction based on whether the activity is performed by an employee during regular working hours or outside...

Comparison of switching control algorithms effective in restricting the switching in the neighborhood of the origin

International Nuclear Information System (INIS)

Joung, JinWook; Chung, Lan; Smyth, Andrew W

2010-01-01

The active interaction control (AIC) system consisting of a primary structure, an auxiliary structure and an interaction element was proposed to protect the primary structure against earthquakes and winds. The objective of the AIC system in reducing the responses of the primary structure is fulfilled by activating or deactivating the switching between the engagement and the disengagement of the primary and auxiliary structures through the interaction element. The status of the interaction element is controlled by switching control algorithms. The previously developed switching control algorithms require an excessive amount of switching, which is inefficient. In this paper, the excessive amount of switching is restricted by imposing an appropriately designed switching boundary region, where switching is prohibited, on pre-designed engagement–disengagement conditions. Two different approaches are used in designing the newly proposed AID-off and AID-off 2 algorithms. The AID-off 2 algorithm is designed to affect deactivated switching regions explicitly, unlike the AID-off algorithm, which follows the same procedure of designing the engagement–disengagement conditions of the previously developed algorithms, by using the current status of the AIC system. Both algorithms are shown to be effective in reducing the amount of switching times triggered from the previously developed AID algorithm under an appropriately selected control sampling period for different earthquakes, but the AID-off 2 algorithm outperforms the AID-off algorithm in reducing the number of switching times

Activator Protein-1: redox switch controlling structure and DNA-binding

Energy Technology Data Exchange (ETDEWEB)

Yin, Zhou; Machius, Mischa; Nestler, Eric J.; Rudenko, Gabby (Texas-MED); (Icahn)

2017-09-07

The transcription factor, activator protein-1 (AP-1), binds to cognate DNA under redox control; yet, the underlying mechanism has remained enigmatic. A series of crystal structures of the AP-1 FosB/JunD bZIP domains reveal ordered DNA-binding regions in both FosB and JunD even in absence DNA. However, while JunD is competent to bind DNA, the FosB bZIP domain must undergo a large conformational rearrangement that is controlled by a ‘redox switch’ centered on an inter-molecular disulfide bond. Solution studies confirm that FosB/JunD cannot undergo structural transition and bind DNA when the redox-switch is in the ‘OFF’ state, and show that the mid-point redox potential of the redox switch affords it sensitivity to cellular redox homeostasis. The molecular and structural studies presented here thus reveal the mechanism underlying redox-regulation of AP-1 Fos/Jun transcription factors and provide structural insight for therapeutic interventions targeting AP-1 proteins.

The Development of the Electrically Controlled High Power RF Switch and Its Application to Active RF Pulse Compression Systems

Energy Technology Data Exchange (ETDEWEB)

Guo, Jiquan [Stanford Univ., CA (United States)

2008-12-01

In the past decades, there has been increasing interest in pulsed high power RF sources for building high-gradient high-energy particle accelerators. Passive RF pulse compression systems have been used in many applications to match the available RF sources to the loads requiring higher RF power but a shorter pulse. Theoretically, an active RF pulse compression system has the advantage of higher efficiency and compactness over the passive system. However, the key component for such a system an element capable of switching hundreds of megawatts of RF power in a short time compared to the compressed pulse width is still an open problem. In this dissertation, we present a switch module composed of an active window based on the bulk effects in semiconductor, a circular waveguide three-port network and a movable short plane, with the capability to adjust the S-parameters before and after switching. The RF properties of the switch module were analyzed. We give the scaling laws of the multiple-element switch systems, which allow the expansion of the system to a higher power level. We present a novel overmoded design for the circular waveguide three-port network and the associated circular-to-rectangular mode-converter. We also detail the design and synthesis process of this novel mode-converter. We demonstrate an electrically controlled ultra-fast high power X-band RF active window built with PIN diodes on high resistivity silicon. The window is capable of handling multi-megawatt RF power and can switch in 2-300ns with a 1000A current driver. A low power active pulse compression experiment was carried out with the switch module and a 375ns resonant delay line, obtaining 8 times compression gain with a compression ratio of 20.

Modelling and properties of a nonlinear autonomous switching system in fed-batch culture of glycerol

Science.gov (United States)

Wang, Juan; Sun, Qingying; Feng, Enmin

2012-11-01

A nonlinear autonomous switching system is proposed to describe the coupled fed-batch fermentation with the pH as the feedback parameter. We prove the non-Zeno behaviors of the switching system and some basic properties of its solution, including the existence, uniqueness, boundedness and regularity. Numerical simulation is also carried out, which reveals that the proposed system can describe the factual fermentation process properly.

Sleep Spindles in the Right Hemisphere Support Awareness of Regularities and Reflect Pre-Sleep Activations.

Science.gov (United States)

Yordanova, Juliana; Kolev, Vasil; Bruns, Eike; Kirov, Roumen; Verleger, Rolf

2017-11-01

The present study explored the sleep mechanisms which may support awareness of hidden regularities. Before sleep, 53 participants learned implicitly a lateralized variant of the serial response-time task in order to localize sensorimotor encoding either in the left or right hemisphere and induce implicit regularity representations. Electroencephalographic (EEG) activity was recorded at multiple electrodes during both task performance and sleep, searching for lateralized traces of the preceding activity during learning. Sleep EEG analysis focused on region-specific slow (9-12 Hz) and fast (13-16 Hz) sleep spindles during nonrapid eye movement sleep. Fast spindle activity at those motor regions that were activated during learning increased with the amount of postsleep awareness. Independently of side of learning, spindle activity at right frontal and fronto-central regions was involved: there, fast spindles increased with the transformation of sequence knowledge from implicit before sleep to explicit after sleep, and slow spindles correlated with individual abilities of gaining awareness. These local modulations of sleep spindles corresponded to regions with greater presleep activation in participants with postsleep explicit knowledge. Sleep spindle mechanisms are related to explicit awareness (1) by tracing the activation of motor cortical and right-hemisphere regions which had stronger involvement already during learning and (2) by recruitment of individually consolidated processing modules in the right hemisphere. The integration of different sleep spindle mechanisms with functional states during wake collectively supports the gain of awareness of previously experienced regularities, with a special role for the right hemisphere. © Sleep Research Society 2017. Published by Oxford University Press [on behalf of the Sleep Research Society].

Communication over the network of binary switches regulates the activation of A2A adenosine receptor.

Directory of Open Access Journals (Sweden)

Yoonji Lee

2015-02-01

Full Text Available Dynamics and functions of G-protein coupled receptors (GPCRs are accurately regulated by the type of ligands that bind to the orthosteric or allosteric binding sites. To glean the structural and dynamical origin of ligand-dependent modulation of GPCR activity, we performed total ~ 5 μsec molecular dynamics simulations of A2A adenosine receptor (A2AAR in its apo, antagonist-bound, and agonist-bound forms in an explicit water and membrane environment, and examined the corresponding dynamics and correlation between the 10 key structural motifs that serve as the allosteric hotspots in intramolecular signaling network. We dubbed these 10 structural motifs "binary switches" as they display molecular interactions that switch between two distinct states. By projecting the receptor dynamics on these binary switches that yield 2(10 microstates, we show that (i the receptors in apo, antagonist-bound, and agonist-bound states explore vastly different conformational space; (ii among the three receptor states the apo state explores the broadest range of microstates; (iii in the presence of the agonist, the active conformation is maintained through coherent couplings among the binary switches; and (iv to be most specific, our analysis shows that W246, located deep inside the binding cleft, can serve as both an agonist sensor and actuator of ensuing intramolecular signaling for the receptor activation. Finally, our analysis of multiple trajectories generated by inserting an agonist to the apo state underscores that the transition of the receptor from inactive to active form requires the disruption of ionic-lock in the DRY motif.

UNFOLDED REGULAR AND SEMI-REGULAR POLYHEDRA

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IONIŢĂ Elena

2015-06-01

Full Text Available This paper proposes a presentation unfolding regular and semi-regular polyhedra. Regular polyhedra are convex polyhedra whose faces are regular and equal polygons, with the same number of sides, and whose polyhedral angles are also regular and equal. Semi-regular polyhedra are convex polyhedra with regular polygon faces, several types and equal solid angles of the same type. A net of a polyhedron is a collection of edges in the plane which are the unfolded edges of the solid. Modeling and unfolding Platonic and Arhimediene polyhedra will be using 3dsMAX program. This paper is intended as an example of descriptive geometry applications.

Buck Converter with Soft-Switching Cells for PV Panel Applications

Directory of Open Access Journals (Sweden)

Cheng-Tao Tsai

2016-03-01

Full Text Available In power conversion of photovoltaic (PV energy, a hard-switching buck converter always generates some disadvantages. For example, serious electromagnetic interference (EMI, high switching losses, and stresses on an active switch (metal-oxide-semiconductor-field-effect-transistor, MOSFET, and high reverse-recovery losses of a freewheeling diode result in low conversion efficiency. To release these disadvantages, a buck converter with soft-switching cells for PV panel applications is proposed. To create zero-voltage-switching (ZVS features of the active switches, a simple active soft-switching cell with an inductor, a capacitor, and a MOSFET is incorporated into the proposed buck converter. Therefore, the switching losses and stresses of the active switches and EMI can be reduced significantly. To reduce reverse-recovery losses of a freewheeling diode, a simple passive soft-switching cell with a capacitor and two diodes is implemented. To verify the performance and the feasibility of the proposed buck converter with soft-switching cells for PV panel applications, a prototype soft-switching buck converter is built and implemented by using a maximum-power-point-tracking (MPPT method. Simulated and experimental results are presented from a 100 W soft-switching buck converter for PV panel applications.

Interrupting Prolonged Sitting with Regular Activity Breaks does not Acutely Influence Appetite: A Randomised Controlled Trial.

Science.gov (United States)

Mete, Evelyn M; Perry, Tracy L; Haszard, Jillian J; Homer, Ashleigh R; Fenemor, Stephen P; Rehrer, Nancy J; Skeaff, C Murray; Peddie, Meredith C

2018-01-26

Regular activity breaks increase energy expenditure; however, this may promote compensatory eating behaviour. The present study compared the effects of regular activity breaks and prolonged sitting on appetite. In a randomised, cross-over trial, 36 healthy adults (BMI (Body Mass Index) 23.9 kg/m² (S.D. = 3.9)) completed four, two-day interventions: two with prolonged sitting (SIT), and two with sitting and 2 min of walking every 30 min (RAB). Standardized meals were provided throughout the intervention, with an ad libitum meal at the end of Day 2. Appetite and satiety were assessed throughout both days of each intervention using five visual analogue scales. The five responses were combined into a single appetite response at each time point. The area under the appetite response curve (AUC) was calculated for each day. Intervention effects for appetite response AUC and ad libitum meal intake were tested using linear mixed models. Appetite AUC did not differ between interventions (standardised effect of RAB compared to SIT: Day 1: 0.11; 95% CI: -0.28, 0.06; p = 0.212; Day 2: 0.04; 95% CI: -0.15, 0.24; p = 0.648). There was no significant difference in energy consumed at the ad libitum lunch meal on Day 2 between RAB and SIT. Interrupting prolonged sitting with regular activity breaks does not acutely influence appetite or volume of food consumed, despite inferred increases in energy expenditure. Longer-term investigation into the effects of regular activity breaks on energy balance is warranted.

Interrupting Prolonged Sitting with Regular Activity Breaks does not Acutely Influence Appetite: A Randomised Controlled Trial

Directory of Open Access Journals (Sweden)

Evelyn M. Mete

2018-01-01

Full Text Available Regular activity breaks increase energy expenditure; however, this may promote compensatory eating behaviour. The present study compared the effects of regular activity breaks and prolonged sitting on appetite. In a randomised, cross-over trial, 36 healthy adults (BMI (Body Mass Index 23.9 kg/m2 (S.D. = 3.9 completed four, two-day interventions: two with prolonged sitting (SIT, and two with sitting and 2 min of walking every 30 min (RAB. Standardized meals were provided throughout the intervention, with an ad libitum meal at the end of Day 2. Appetite and satiety were assessed throughout both days of each intervention using five visual analogue scales. The five responses were combined into a single appetite response at each time point. The area under the appetite response curve (AUC was calculated for each day. Intervention effects for appetite response AUC and ad libitum meal intake were tested using linear mixed models. Appetite AUC did not differ between interventions (standardised effect of RAB compared to SIT: Day 1: 0.11; 95% CI: −0.28, 0.06; p = 0.212; Day 2: 0.04; 95% CI: −0.15, 0.24; p = 0.648. There was no significant difference in energy consumed at the ad libitum lunch meal on Day 2 between RAB and SIT. Interrupting prolonged sitting with regular activity breaks does not acutely influence appetite or volume of food consumed, despite inferred increases in energy expenditure. Longer-term investigation into the effects of regular activity breaks on energy balance is warranted.

Predicting Factors Associated with Regular Physical Activity among College Students: Applying BASNEF Model

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B. Moeini

2011-10-01

Full Text Available Introduction & Objective: One of the important problems in modern society is people's sedentary life style. The aim of this study was to determine factors associated with regular physical activity among college students based on BASNEF model.Materials & Methods: This study was a cross-sectional study carried out on 400 students in Hamadan University of Medical Sciences. Based on the assignment among different schools, classified sampling method was chosen for data gathering using a questionnaire in three parts including: demographic information, constructs of BASNEF model, and standard international physical activity questionnaire (IPAQ. Data were analyzed by SPSS-13, and using appropriate statistical tests (Chi-square, T-test and regression. Results: Based on the results, 271 students(67.8 % had low, 124 (31% moderate ,and 5 (1.2% vigorous physical activity. There was a significant relationship (c2=6.739, df= 1, P= 0.034 between their residence and physical activity and students living in dormitory were reported to have higher level of physical activity. Behavioral intention and enabling factors from the constructs of BASNEF model were the best predictors for having physical activity in students (OR=1.215, P = 0.000 and (OR=1.119, P= 0.000 respectively.Conclusion: With regard to the fact that majority of the students did not engage in enough physical activity and enabling factors were the most effective predictors for having regular physical activity in them, it seems that providing sports facilities can promote physical activity among the students.(Sci J Hamadan Univ Med Sci 2011;18(3:70-76

Effects of fundamentals acquisition and strategy switch on stock price dynamics

Science.gov (United States)

Wu, Songtao; He, Jianmin; Li, Shouwei

2018-02-01

An agent-based artificial stock market is developed to simulate trading behavior of investors. In the market, acquisition and employment of information about fundamentals and strategy switch are investigated to explain stock price dynamics. Investors could obtain the information from both market and neighbors resided on their social networks. Depending on information status and performances of different strategies, an informed investor may switch to the strategy of fundamentalist. This in turn affects the information acquisition process, since fundamentalists are more inclined to search and spread the information than chartists. Further investigation into price dynamics generated from three typical networks, i.e. regular lattice, small-world network and random graph, are conducted after general relation between network structures and price dynamics is revealed. In each network, integrated effects of different combinations of information efficiency and switch intensity are investigated. Results have shown that, along with increasing switch intensity, market and social information efficiency play different roles in the formation of price distortion, standard deviation and kurtosis of returns.

Electrochemical Switching of Conductance with Diarylethene-Based Redox-Active Polymers

DEFF Research Database (Denmark)

Logtenberg, Hella; van der Velde, Jasper H. M.; de Mendoza, Paula

2012-01-01

Reversible switching of conductance using redox triggered switching of a polymer-modified electrode is demonstrated. A bifunctional monomer comprising a central electroswitchable core and two bithiophene units enables formation of a film through anodic electropolymerization. The conductivity...... of the polymer can be switched electrochemically in a reversible manner by redox triggered opening and closing of the diarylethene unit. In the closed state, the conductivity of the modified electrode is higher than in the open state....

Control and switching synchronization of fractional order chaotic systems using active control technique

KAUST Repository

Radwan, A.G.; Moaddy, K.; Salama, Khaled N.; Momani, S.; Hashim, I.

2013-01-01

This paper discusses the continuous effect of the fractional order parameter of the Lü system where the system response starts stable, passing by chaotic behavior then reaching periodic response as the fractional-order increases. In addition, this paper presents the concept of synchronization of different fractional order chaotic systems using active control technique. Four different synchronization cases are introduced based on the switching parameters. Also, the static and dynamic synchronizations can be obtained when the switching parameters are functions of time. The nonstandard finite difference method is used for the numerical solution of the fractional order master and slave systems. Many numeric simulations are presented to validate the concept for different fractional order parameters.

Control and switching synchronization of fractional order chaotic systems using active control technique

KAUST Repository

Radwan, A.G.

2013-03-13

This paper discusses the continuous effect of the fractional order parameter of the Lü system where the system response starts stable, passing by chaotic behavior then reaching periodic response as the fractional-order increases. In addition, this paper presents the concept of synchronization of different fractional order chaotic systems using active control technique. Four different synchronization cases are introduced based on the switching parameters. Also, the static and dynamic synchronizations can be obtained when the switching parameters are functions of time. The nonstandard finite difference method is used for the numerical solution of the fractional order master and slave systems. Many numeric simulations are presented to validate the concept for different fractional order parameters.

Cardiac contractility structure-activity relationship and ligand-receptor interactions; the discovery of unique and novel molecular switches in myosuppressin signaling.

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Megan Leander

Full Text Available Peptidergic signaling regulates cardiac contractility; thus, identifying molecular switches, ligand-receptor contacts, and antagonists aids in exploring the underlying mechanisms to influence health. Myosuppressin (MS, a decapeptide, diminishes cardiac contractility and gut motility. Myosuppressin binds to G protein-coupled receptor (GPCR proteins. Two Drosophila melanogaster myosuppressin receptors (DrmMS-Rs exist; however, no mechanism underlying MS-R activation is reported. We predicted DrmMS-Rs contained molecular switches that resembled those of Rhodopsin. Additionally, we believed DrmMS-DrmMS-R1 and DrmMS-DrmMS-R2 interactions would reflect our structure-activity relationship (SAR data. We hypothesized agonist- and antagonist-receptor contacts would differ from one another depending on activity. Lastly, we expected our study to apply to other species; we tested this hypothesis in Rhodnius prolixus, the Chagas disease vector. Searching DrmMS-Rs for molecular switches led to the discovery of a unique ionic lock and a novel 3-6 lock, as well as transmission and tyrosine toggle switches. The DrmMS-DrmMS-R1 and DrmMS-DrmMS-R2 contacts suggested tissue-specific signaling existed, which was in line with our SAR data. We identified R. prolixus (RhpMS-R and discovered it, too, contained the unique myosuppressin ionic lock and novel 3-6 lock found in DrmMS-Rs as well as transmission and tyrosine toggle switches. Further, these motifs were present in red flour beetle, common water flea, honey bee, domestic silkworm, and termite MS-Rs. RhpMS and DrmMS decreased R. prolixus cardiac contractility dose dependently with EC50 values of 140 nM and 50 nM. Based on ligand-receptor contacts, we designed RhpMS analogs believed to be an active core and antagonist; testing on heart confirmed these predictions. The active core docking mimicked RhpMS, however, the antagonist did not. Together, these data were consistent with the unique ionic lock, novel 3-6 lock

The Switch from Low-Pressure Sodium to Light Emitting Diodes Does Not Affect Bat Activity at Street Lights.

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Elizabeth G Rowse

Full Text Available We used a before-after-control-impact paired design to examine the effects of a switch from low-pressure sodium (LPS to light emitting diode (LED street lights on bat activity at twelve sites across southern England. LED lights produce broad spectrum 'white' light compared to LPS street lights that emit narrow spectrum, orange light. These spectral differences could influence the abundance of insects at street lights and thereby the activity of the bats that prey on them. Most of the bats flying around the LPS lights were aerial-hawking species, and the species composition of bats remained the same after the switch-over to LED. We found that the switch-over from LPS to LED street lights did not affect the activity (number of bat passes, or the proportion of passes containing feeding buzzes, of those bat species typically found in close proximity to street lights in suburban environments in Britain. This is encouraging from a conservation perspective as many existing street lights are being, or have been, switched to LED before the ecological consequences have been assessed. However, lighting of all spectra studied to date generally has a negative impact on several slow-flying bat species, and LED lights are rarely frequented by these 'light-intolerant' bat species.

The Switch from Low-Pressure Sodium to Light Emitting Diodes Does Not Affect Bat Activity at Street Lights

Science.gov (United States)

Rowse, Elizabeth G.; Harris, Stephen; Jones, Gareth

2016-01-01

We used a before-after-control-impact paired design to examine the effects of a switch from low-pressure sodium (LPS) to light emitting diode (LED) street lights on bat activity at twelve sites across southern England. LED lights produce broad spectrum ‘white’ light compared to LPS street lights that emit narrow spectrum, orange light. These spectral differences could influence the abundance of insects at street lights and thereby the activity of the bats that prey on them. Most of the bats flying around the LPS lights were aerial-hawking species, and the species composition of bats remained the same after the switch-over to LED. We found that the switch-over from LPS to LED street lights did not affect the activity (number of bat passes), or the proportion of passes containing feeding buzzes, of those bat species typically found in close proximity to street lights in suburban environments in Britain. This is encouraging from a conservation perspective as many existing street lights are being, or have been, switched to LED before the ecological consequences have been assessed. However, lighting of all spectra studied to date generally has a negative impact on several slow-flying bat species, and LED lights are rarely frequented by these ‘light-intolerant’ bat species. PMID:27008274

Physiological Aging Influence on Brain Hemodynamic Activity during Task-Switching: A fNIRS Study.

Science.gov (United States)

Vasta, Roberta; Cutini, Simone; Cerasa, Antonio; Gramigna, Vera; Olivadese, Giuseppe; Arabia, Gennarina; Quattrone, Aldo

2017-01-01

Task-switching (TS) paradigm is a well-known validated tool useful for exploring the neural substrates of cognitive control, in particular the activity of the lateral and medial prefrontal cortex. This work is aimed at investigating how physiological aging influences hemodynamic response during the execution of a color-shape TS paradigm. A multi-channel near infrared spectroscopy (fNIRS) was used to measure hemodynamic activity in 27 young (30.00 ± 7.90 years) and 11 elderly participants (57.18 ± 9.29 years) healthy volunteers (55% male, age range: (19-69) years) during the execution of a TS paradigm. Two holders were placed symmetrically over the left/right hemispheres to record cortical activity [oxy-(HbO) and deoxy-hemoglobin (HbR) concentration] of the dorso-lateral prefrontal cortex (DLPFC), the dorsal premotor cortex (PMC), and the dorso-medial part of the superior frontal gyrus (sFG). TS paradigm requires participants to repeat the same task over a variable number of trials, and then to switch to a different task during the trial sequence. A two-sample t -test was carried out to detect differences in cortical responses between groups. Multiple linear regression analysis was used to evaluate the impact of age on the prefrontal neural activity. Elderly participants were significantly slower than young participants in both color- ( p aging. Multivariate regression analysis revealed that the HbO mean concentration of switching task in the PMC ( p = 0.01, β = -0.321) and of shape single-task in the sFG ( p = 0.003, β = 0.342) were the best predictors of age effects. Our findings demonstrated that TS might be a reliable instrument to gather a measure of cognitive resources in older people. Moreover, the fNIRS-related brain activity extracted from frontoparietal cortex might become a useful indicator of aging effects.

Complementary resistive switching in BaTiO3/NiO bilayer with opposite switching polarities

Science.gov (United States)

Li, Shuo; Wei, Xianhua; Lei, Yao; Yuan, Xincai; Zeng, Huizhong

2016-12-01

Resistive switching behaviors have been investigated in the Au/BaTiO3/NiO/Pt structure by stacking the two elements with different switching types. The conducting atomic force microscope measurements on BaTiO3 thin films and NiO thin films suggest that with the same active resistive switching region, the switching polarities in the two semiconductors are opposite to each other. It is in agreement with the bipolar hysteresis I-V curves with opposite switching polarities for single-layer devices. The bilayer devices show complementary resistive switching (CRS) without electroforming and unipolar resistive switching (URS) after electroforming. The coexistence of CRS and URS is mainly ascribed to the co-effect of electric field and Joule heating mechanisms, indicating that changeable of resistance in this device is dominated by the redistribution of oxygen vacancies in BaTiO3 and the formation, disruption, restoration of conducting filaments in NiO. CRS in bilayer with opposite switching polarities is effective to solve the sneak current without the introduction of any selector elements or an additional metal electrode.

Comparison of Small-Scale Actively and Passively Q-Switched Eye-Safe Intracavity Optical Parametric Oscillators at 1.57 μm

International Nuclear Information System (INIS)

Miao Jie-Guang; Pan Yu-Zhai; Qu Shi-Liang

2012-01-01

The first experimental comparison between the actively and passively Q-switched intracavity optical parametric oscillators (IOPOs) at 1.57 μm driven by a small-scale diode-pumped Nd:YVO 4 laser are thoroughly presented. It is found that the performances of the two types of IOPOs are complementary. The actively Q-switched IOPO features a shorter pulse duration, a higher peak power, and a superior power and pulse stability. However, in terms of compactness, operation threshold and conversion efficiency, passively Q-switched IOPOs are more attractive. It is further indicated that the passively Q-switched IOPO at 1.57μm is a promising and cost-effective eye-safe laser source, especially at the low and moderate output levels. In addition, instructional improvement measures for the two types of IOPOs are also summarized. (fundamental areas of phenomenology(including applications))

High repetition rate, high energy, actively Q-switched all-in-fiber laser

Science.gov (United States)

Lecourt, J. B.; Bertrand, A.; Guillemet, S.; Hernandez, Y.; Giannone, D.

2010-05-01

We report an actively Q-switched Ytterbium-doped all-in-fibre laser delivering 10ns pulses with high repetition rate (from 100kHz to 1MHz). The laser operation has been validated at three different wavelengths (1040, 1050 and 1064nm). The laser can deliver up to 20Watts average power with an high beam quality (M2 = 1).

Comparative efficacy of switching to natalizumab in active multiple sclerosis

DEFF Research Database (Denmark)

Spelman, Timothy; Kalincik, Tomas; Zhang, Annie

2015-01-01

OBJECTIVE: To compare treatment efficacy and persistence in patients who switched to natalizumab versus those who switched between glatiramer acetate (GA) and interferon-beta (IFNβ) after an on-treatment relapse on IFNβ or GA using propensity score matched real-world datasets. METHODS: Patients...... included were registered in MSBase or the TYSABRI Observational Program (TOP), had relapsed on IFNβ or GA within 12 months prior to switching to another therapy, and had initiated natalizumab or IFNβ/GA treatment ≤6 months after discontinuing prior therapy. Covariates were balanced across post switch...... treatment groups by propensity score matching at treatment initiation. Relapse, persistence, and disability measures were compared between matched treatment arms in the total population (n = 869/group) and in subgroups defined by prior treatment history (IFNβ only [n = 578/group], GA only [n = 165/group...

Gas adsorption/absorption heat switch, phase 1

Science.gov (United States)

Chan, C. K.

1987-01-01

The service life and/or reliability of far-infrared sensors on surveillance satellites is presently limited by the cryocooler. The life and/or reliability, however, can be extended by using redundant cryocoolers. To reduce parasitic heat leak, each stage of the inactive redundant cryocooler must be thermally isolated from the optical system, while each stage of the active cryocooler must be thermally connected to the system. The thermal break or the thermal contact can be controlled by heat switches. Among different physical mechanisms for heat switching, mechanically activated heat switches tend to have low reliability and, furthermore, require a large contact force. Magnetoresistive heat switches are, except at very low temperatures, of very low efficiency. Heat switches operated by the heat pipe principle usually require a long response time. A sealed gas gap heat switch operated by an adsorption pump has no mechanical motion and should provide the reliability and long lifetime required in long-term space missions. Another potential application of a heat switch is the thermal isolation of the optical plane during decontamination.

Dual regulatory switch confers tighter control on HtrA2 proteolytic activity.

Science.gov (United States)

Singh, Nitu; D'Souza, Areetha; Cholleti, Anuradha; Sastry, G Madhavi; Bose, Kakoli

2014-05-01

High-temperature requirement protease A2 (HtrA2), a multitasking serine protease that is involved in critical biological functions and pathogenicity, such as apoptosis and cancer, is a potent therapeutic target. It is established that the C-terminal post-synaptic density protein, Drosophila disc large tumor suppressor, zonula occludens-1 protein (PDZ) domain of HtrA2 plays pivotal role in allosteric modulation, substrate binding and activation, as commonly reported in other members of this family. Interestingly, HtrA2 exhibits an additional level of functional modulation through its unique N-terminus, as is evident from 'inhibitor of apoptosis proteins' binding and cleavage. This phenomenon emphasizes multiple activation mechanisms, which so far remain elusive. Using conformational dynamics, binding kinetics and enzymology studies, we addressed this complex behavior with respect to defining its global mode of regulation and activity. Our findings distinctly demonstrate a novel N-terminal ligand-mediated triggering of an allosteric switch essential for transforming HtrA2 to a proteolytically competent state in a PDZ-independent yet synergistic activation process. Dynamic analyses suggested that it occurs through a series of coordinated structural reorganizations at distal regulatory loops (L3, LD, L1), leading to a population shift towards the relaxed conformer. This precise synergistic coordination among different domains might be physiologically relevant to enable tighter control upon HtrA2 activation for fostering its diverse cellular functions. Understanding this complex rheostatic dual switch mechanism offers an opportunity for targeting various disease conditions with tailored site-specific effector molecules. © 2014 FEBS.

Regular physical activity modifies smoking-related lung function decline and reduces risk of chronic obstructive pulmonary disease: a population-based cohort study

DEFF Research Database (Denmark)

Garcia-Aymerich, J; Lange, Peter; Benet, M

2007-01-01

RATIONALE: We have previously reported that regular physical activity reduces risk of chronic obstructive pulmonary disease (COPD) exacerbation. We hypothesized that higher levels of regular physical activity could reduce the risk of COPD by modifying smoking-related lung function decline....... OBJECTIVE: To estimate the longitudinal association between regular physical activity and FEV(1) and FVC decline and COPD risk. METHODS: A population-based sample (n = 6,790) was recruited and assessed with respect to physical activity, smoking, lung function, and other covariates, in Copenhagen in 1981....../yr of FEV(1), P-for-trend = 0.006, and +2.6 and +7.7 ml/yr of FVC, P-for-trend function decline. Active smokers with moderate to high physical activity had...

Energy storage, compression, and switching. Vol. 2

International Nuclear Information System (INIS)

Nardi, V.; Bostick, W.H.; Sahlin, H.

1983-01-01

This book is a compilation of papers presented at the Second International Conference on Energy Storage, Compression, and Switching, which was held in order to assemble active researchers with a major interest in plasma physics, electron beams, electric and magnetic energy storage systems, high voltage and high current switches, free-electron lasers, and pellet implosion plasma focus. Topics covered include: Slow systems: 50-60 Hz machinery, homopolar generators, slow capacitors, inductors, and solid state switches; Intermediate systems: fast capacitor banks; superconducting storage and switching; gas, vacuum, and dielectric switching; nonlinear (magnetic) switching; imploding liners capacitors; explosive generators; and fuses; and Fast systems: Marx, Blumlein, oil, water, and pressurized water dielectrics; switches; magnetic insulation; electron beams; and plasmas

Active and fast charge-state switching of single NV centres in diamond by in-plane Al-Schottky junctions

Directory of Open Access Journals (Sweden)

Christoph Schreyvogel

2016-11-01

Full Text Available In this paper, we demonstrate an active and fast control of the charge state and hence of the optical and electronic properties of single and near-surface nitrogen-vacancy centres (NV centres in diamond. This active manipulation is achieved by using a two-dimensional Schottky-diode structure from diamond, i.e., by using aluminium as Schottky contact on a hydrogen terminated diamond surface. By changing the applied potential on the Schottky contact, we are able to actively switch single NV centres between all three charge states NV+, NV0 and NV− on a timescale of 10 to 100 ns, corresponding to a switching frequency of 10–100 MHz. This switching frequency is much higher than the hyperfine interaction frequency between an electron spin (of NV− and a nuclear spin (of 15N or 13C for example of 2.66 kHz. This high-frequency charge state switching with a planar diode structure would open the door for many quantum optical applications such as a quantum computer with single NVs for quantum information processing as well as single 13C atoms for long-lifetime storage of quantum information. Furthermore, a control of spectral emission properties of single NVs as a single photon emitters – embedded in photonic structures for example – can be realized which would be vital for quantum communication and cryptography.

Coherent Multimodal Sensory Information Allows Switching between Gravitoinertial Contexts

OpenAIRE

Marie Barbiero; Marie Barbiero; Célia Rousseau; Célia Rousseau; Charalambos Papaxanthis; Charalambos Papaxanthis; Olivier White; Olivier White

2017-01-01

Whether the central nervous system is capable to switch between contexts critically depends on experimental details. Motor control studies regularly adopt robotic devices to perturb the dynamics of a certain task. Other approaches investigate motor control by altering the gravitoinertial context itself as in parabolic flights and human centrifuges. In contrast to conventional robotic experiments, where only the hand is perturbed, these gravitoinertial or immersive settings coherently plunge p...

Alteration of Neurokinin B Gene Expression and Hypothalamic-Pituitary- Gonadal Axis in Response to One-month Regular Moderate Physical Activity

Directory of Open Access Journals (Sweden)

Nazli Khajehnasiri

2017-08-01

Full Text Available Abstract Background: The advantageous effects of the regular moderate physical activity (Exercise on reproduction is widely accepted, but until now, the alterations of the expression of hypothalamic arcuate nuclei gene affecting on reproduction axis in response to this type of physical activity are not clear. Therefore, the goal of the present investigation was to study the effect of one –month regular moderate physical activity on neurokinin B gene expression and reproductive axis hormonal changes. Materials and Methods: In the experimental study, fourteen adult male Wistar rats were randomly divided into control and one- month regular moderate exercise groups. After one - month physical activity (20m/min, the arcuate nucleus was isolated from brain and stored in -80 refrigerators for neurokinin B gene expression assay by Real-time PCR method. In addition, serum samples were taken to assess the corticosterone, luteinizing hormone and testosterone levels by ELISA method. Data were analyzed by Independent t-test in SPSS. Results: Neurokinin-B gene expression level was lower in the group which received physical activity than the control group(p<0.05. Also, corticosterone serum concentration was decreased in the physical activity group(p<0.05. By contrast, the physical activity induced luteinizing hormone and Testosterone serum levels evaluation in exersice group compared with control group (p<0.05. Conclusion: Regular moderate physical activity may improve male reproductive performance by reducing the corticosterone hormone level and decreasing neurokinin B expression.

Dendritic slow dynamics enables localized cortical activity to switch between mobile and immobile modes with noisy background input.

Directory of Open Access Journals (Sweden)

Hiroki Kurashige

Full Text Available Mounting lines of evidence suggest the significant computational ability of a single neuron empowered by active dendritic dynamics. This motivates us to study what functionality can be acquired by a network of such neurons. The present paper studies how such rich single-neuron dendritic dynamics affects the network dynamics, a question which has scarcely been specifically studied to date. We simulate neurons with active dendrites networked locally like cortical pyramidal neurons, and find that naturally arising localized activity--called a bump--can be in two distinct modes, mobile or immobile. The mode can be switched back and forth by transient input to the cortical network. Interestingly, this functionality arises only if each neuron is equipped with the observed slow dendritic dynamics and with in vivo-like noisy background input. If the bump activity is considered to indicate a point of attention in the sensory areas or to indicate a representation of memory in the storage areas of the cortex, this would imply that the flexible mode switching would be of great potential use for the brain as an information processing device. We derive these conclusions using a natural extension of the conventional field model, which is defined by combining two distinct fields, one representing the somatic population and the other representing the dendritic population. With this tool, we analyze the spatial distribution of the degree of after-spike adaptation and explain how we can understand the presence of the two distinct modes and switching between the modes. We also discuss the possible functional impact of this mode-switching ability.

Irradiation of optically activated SI-GaAs high-voltage switches with low and high energy protons

CERN Document Server

Bertolucci, Ennio; Mettivier, G; Russo, P; Bisogni, M G; Bottigli, U; Fantacci, M E; Stefanini, A; Cola, A; Quaranta, F; Vasanelli, L; Stefanini, G

1999-01-01

Semi-Insulating Gallium Arsenide (SI-GaAs) devices have been tested for radiation hardness with 3-4 MeV or 24 GeV proton beams. These devices can be operated in dc mode as optically activated electrical switches up to 1 kV. Both single switches (vertical Schottky diodes) and multiple (8) switches (planar devices) have been studied, by analyzing their current-voltage (I-V) reverse characteristics in the dark and under red light illumination, both before and after irradiation. We propose to use them in the system of high-voltage (-600 V) switches for the microstrip gas chambers for the CMS experiment at CERN. Low energy protons (3-4 MeV) were used in order to produce a surface damage below the Schottky contact: their fluence (up to 2.6*10/sup 15/ p/cm/sup 2/) gives a high-dose irradiation. The high energy proton irradiation (energy: 24 GeV, fluence: 1.1*10/sup 14/ p/cm/sup 2/) reproduced a ten years long proton exposure of the devices in CMS experiment conditions. For low energy irradiation, limited changes of ...

Switching dynamics of TaOx-based threshold switching devices

Science.gov (United States)

Goodwill, Jonathan M.; Gala, Darshil K.; Bain, James A.; Skowronski, Marek

2018-03-01

Bi-stable volatile switching devices are being used as access devices in solid-state memory arrays and as the active part of compact oscillators. Such structures exhibit two stable states of resistance and switch between them at a critical value of voltage or current. A typical resistance transient under a constant amplitude voltage pulse starts with a slow decrease followed by a rapid drop and leveling off at a low steady state value. This behavior prompted the interpretation of initial delay and fast transition as due to two different processes. Here, we show that the entire transient including incubation time, transition time, and the final resistance values in TaOx-based switching can be explained by one process, namely, Joule heating with the rapid transition due to the thermal runaway. The time, which is required for the device in the conducting state to relax back to the stable high resistance one, is also consistent with the proposed mechanism.

A novel carbon gun for use with plasma opening switches

International Nuclear Information System (INIS)

Stevenson, P.; Gregory, K.; Cliffe, R.J.; Smith, I.R.

2001-01-01

The carbon gun is probably the most common plasma source used in plasma opening switches. Nevertheless, it either produces a contaminated plasma, as the flashover surface erodes, or requires regular treatment with graphite paint. The novel form of the plasma gun described in this paper overcomes the disadvantages of existing designs and produces a cleaner plasma. Experimental results illustrate the performance of a prototype system. (author)

Photonics in switching: enabling technologies and subsystem design

DEFF Research Database (Denmark)

Vlachos, K.; Raffaelli, C.; Aleksic, S.

2009-01-01

This paper describes recent research activities and results in the area of photonic switching carried out within the framework of the EU-funded e-Photon/ONe + network of excellence, Virtual Department on Optical Switching. Technology aspects of photonics in switching and, in particular, recent...

Optically triggered high voltage switch network and method for switching a high voltage

Science.gov (United States)

El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Optically triggered high voltage switch network and method for switching a high voltage

Energy Technology Data Exchange (ETDEWEB)

El-Sharkawi, Mohamed A. (Renton, WA); Andexler, George (Everett, WA); Silberkleit, Lee I. (Mountlake Terrace, WA)

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Stochastic multistep polarization switching in ferroelectrics

Science.gov (United States)

Genenko, Y. A.; Khachaturyan, R.; Schultheiß, J.; Ossipov, A.; Daniels, J. E.; Koruza, J.

2018-04-01

Consecutive stochastic 90° polarization switching events, clearly resolved in recent experiments, are described by a nucleation and growth multistep model. It extends the classical Kolmogorov-Avrami-Ishibashi approach and includes possible consecutive 90°- and parallel 180° switching events. The model predicts the results of simultaneous time-resolved macroscopic measurements of polarization and strain, performed on a tetragonal Pb (Zr ,Ti ) O3 ceramic in a wide range of electric fields over a time domain of seven orders of magnitude. It allows the determination of the fractions of individual switching processes, their characteristic switching times, activation fields, and respective Avrami indices.

Theoretical evaluation of the double U-core switched reluctance machine

DEFF Research Database (Denmark)

Jæger, Rasmus; Nielsen, Simon Staal; Rasmussen, Peter Omand

2017-01-01

The switched reluctance machine (SRM) has seen a lot of interest due to its simplicity and ruggedness. Much attention have been paid in academia to improve on some of the disadvantages of the technology such as torque ripple, acoustic noise and low torque density. In this paper a topology, namely...... the double U-core SRM, is reviewed. This topology improves on some of the disadvantages of the regular SRM. Torque ripple is reduced and the torque density is increased for the same amount of material, by reconfiguring the topology of the regular SRM and increasing the number of poles. The result...... is a segmented stator structure where each segment can be wound individually and assembled afterwards. Several similar technologies have been demonstrated, and the claimed advantages have been proven in comparison with regular SRMs with a lower pole count. In this paper, the technology will be compared...

Intensification of regular physical activity in patients with resistant hypertension

Directory of Open Access Journals (Sweden)

Piotr Kruk

2017-09-01

Full Text Available Introduction: Regular physical activity is recommended in patients with arterial hypertension as part of the necessary lifestyle modifications. Aim of the study: The aim of the study was to assess the possibility of increasing the physical activity of patients with resistant hypertension. Material and methods: The study group consisted of 27 patients meeting the diagnosis criteria of resistant hypertension and 26 patients with well-controlled hypertension, as a control group. Anthropometric and bioimpedance-based body composition measurements were performed three times within the course of the 6-month-long study, at baseline and after 3 and 6 months, and a physical activity profile was determined based on the International Physical Activity Questionnaire. The study also included accelerometer measurements conducted for 72 consecutive hours. The participants were recommended to perform regular aerobic physical activity, chosen individually during meetings with the study scientist, in accordance with the guidelines of the American Heart Association. Moreover, the patients were motivated to perform physical activity with short text messages and phone calls. Results: A significant change in the resistant hypertensives was observed after 6 months, regarding the number of steps taken (17,361 ± 6,815 vs. 23,067 ± 7,741; p < 0.005, metabolic equivalent of task (1.325 ± 0.3 vs. 1.464 ± 0.3; p = 0.001, duration of rest (1,595 ± 265 vs. 1,458 ± 292 min; p < 0.05 and sleep (1,278 ± 228 vs. 1,147 ± 270 min; p = 0.02, as assessed based on 3-day accelerometer measurements. An increase in activity was also observed based on the International Physical Activity Questionnaire and positive changes in body composition were determined. Conclusions: In the case of patients with resistant hypertension, intensification of physical activity is a well-tolerated, implementable and

Identifying factors associated with regular physical activity in leisure time among Canadian adolescents.

Science.gov (United States)

Godin, Gaston; Anderson, Donna; Lambert, Léo-Daniel; Desharnais, Raymond

2005-01-01

The purpose of this study was to identify the factors explaining regular physical activity among Canadian adolescents. A cohort study conducted over a period of 2 years. A French-language high school located near Québec City. A cohort of 740 students (352 girls; 388 boys) aged 13.3 +/- 1.0 years at baseline. Psychosocial, life context, profile, and sociodemographic variables were assessed at baseline and 1 and 2 years after baseline. Exercising almost every day during leisure time at each measurement time was the dependent variable. The Generalized Estimating Equations (GEE) analysis indicated that exercising almost every day was significantly associated with a high intention to exercise (odds ratio [OR]: 8.33, confidence interval [CI] 95%: 5.26, 13.18), being satisfied with the activity practiced (OR: 2.07, CI 95%: 1.27, 3.38), perceived descriptive norm (OR: 1.82, CI 95%: 1.41, 2.35), being a boy (OR: 1.83, CI 95%: 1.37, 2.46), practicing "competitive" activities (OR: 1.80, CI 95%: 1.37, 2.36), eating a healthy breakfast (OR: 1.68, CI 95%: 1.09, 2.60), and normative beliefs (OR: 1.48, CI 95%: 1.14, 1.90). Specific GEE analysis for gender indicated slight but significant differences. This study provides evidence for the need to design interventions that are gender specific and that focus on increasing intention to exercise regularly.

Study of all optical switching behaviour in semiconductor microresonator with nano-active layer

International Nuclear Information System (INIS)

Kheradmand, R; Aryan, H

2010-01-01

In this paper the behaviour of carriers in spontaneous patterns formation and patterns switching has been studied. Results demonstrate that with increasing length of cavity the range of required input field amplitude for patterns formation increased slightly and also the minimum perturbation coefficient for switching decreased greatly. Increasing nonradiative recombination rate of carriers about ten percent appeared that required input field amplitude for patterns formation raised more than before, albeit the minimum perturbation coefficient for switching and switching and switching time dose not vary considerably.

Study of all optical switching behaviour in semiconductor microresonator with nano-active layer

Energy Technology Data Exchange (ETDEWEB)

Kheradmand, R; Aryan, H, E-mail: r_kheradmand@tabrizu.ac.i, E-mail: aryan86@ms.tabrizu.ac.i [Photonics Group, Research Institute for Applied Physics and Astronomy, Tabriz University, Tabriz (Iran, Islamic Republic of)

2010-11-01

In this paper the behaviour of carriers in spontaneous patterns formation and patterns switching has been studied. Results demonstrate that with increasing length of cavity the range of required input field amplitude for patterns formation increased slightly and also the minimum perturbation coefficient for switching decreased greatly. Increasing nonradiative recombination rate of carriers about ten percent appeared that required input field amplitude for patterns formation raised more than before, albeit the minimum perturbation coefficient for switching and switching and switching time dose not vary considerably.

Regular activity breaks combined with physical activity improve postprandial plasma triglyceride, nonesterified fatty acid, and insulin responses in healthy, normal weight adults: A randomized crossover trial.

Science.gov (United States)

Homer, Ashleigh R; Fenemor, Stephen P; Perry, Tracy L; Rehrer, Nancy J; Cameron, Claire M; Skeaff, C Murray; Peddie, Meredith C

Compared with prolonged sitting, regular activity breaks immediately lower postprandial glucose and insulin, but not triglyceride responses. Postprandial triglycerides can be lowered by physical activity but the effect is often delayed by ∼12 to 24 hours. The objective of the study was to determine whether regular activity breaks affect postprandial triglyceride response in a delayed manner similar to physical activity. In a randomized crossover trial, 36 adults (body mass index 23.9 kg/m 2 [standard deviation 3.9]) completed four 2-day interventions: (1) prolonged sitting (SIT); (2) prolonged sitting with 30 minutes of continuous walking (60% VO 2max ), at the end of Day 1 (SIT + PA D1 ); (3) Sitting with 2 minutes of walking (60% VO 2max ) every 30 minutes (RAB); (4) A combination of the continuous walking and regular activity breaks in 2 and 3 above (RAB + PA D1 ). Postprandial plasma triglyceride, nonesterified fatty acids, glucose, and insulin responses were measured in venous blood over 5 hours on Day 2. Compared with SIT, both RAB (difference: -43.61 mg/dL·5 hours; 95% confidence interval [CI] -83.66 to -2.67; P = .035) and RAB + PA D1 (-65.86 mg/dL·5 hours; 95% CI -112.14 to -19.58; P = .005) attenuated triglyceride total area under the curve (tAUC). RAB + PA D1 produced the greatest reductions in insulin tAUC (-23%; 95% CI -12% to -31%; P glucose tAUC (P = .290). Postprandial triglyceride response is attenuated by regular activity breaks, when measured ∼24 hours after breaks begin. Combining regular activity breaks with 30 minutes of continuous walking further improves insulinemic and lipidemic responses. Copyright © 2017 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Theoretical and experimental study of a laser-diode-pumped actively Q-switched Yb:NaY(WO4)2 laser with acoustic-optic modulator

Science.gov (United States)

Zhang, Haikun; Xia, Wei; Song, Peng; Wang, Jing; Li, Xin

2018-03-01

A laser-diode-pumped actively Q-switched Yb:NaY(WO4)2 laser operating at around 1040 nm is presented for the first time with acoustic-optic modulator. The dependence of pulse width on incident pump power for different pulse repetition rates is measured. By considering the Guassian spatial distribution of the intracavity photon density and the initial population-inversion density as well as the longitudinal distribution of the photon density along the cavity axis and the turn off time of the acoustic-optic Q-switch, the coupled equations of the actively Q-switched Yb:NaY(WO4)2 laser are given. The coupled rate equations are used to simulate the Q-switched process of laser, and the numerical solutions agree with the experimental results.

Reversible control of kinesin activity and microtubule gliding speeds by switching the doping states of a conducting polymer support

Energy Technology Data Exchange (ETDEWEB)

Martin, Brett D [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Velea, Luminita M [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Soto, Carissa M [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Whitaker, Craig M [US Naval Academy, Department of Chemistry, Annapolis, MD 21402 (United States); Gaber, Bruce P [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Ratna, Banahalli [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States)

2007-02-07

We describe a method for reversibly controlling the ATPase activity of streptavidin-linked kinesin by changing the doping states of a conducting polymer support. When the polymer (poly(CH{sub 2}OH-EDOT)) was electrochemically switched from its dedoped (semiconducting) state to its doped (conducting) state, the ATPase activity of the adsorbed kinesin complex decreased by 35% with a concomitant decrease in the gliding speeds of kinesin-driven microtubules. When the polymer was switched back to its original dedoped state, nearly identical increases were observed in the kinesin ATPase activity and microtubule speeds. Use of a fluorescent ATP substrate analogue showed that the total amount of kinesin adsorbed on the poly(CH{sub 2}OH-EDOT) surface remained constant as the doping state of the polymer was switched. The microtubules exhibited nearly identical speed differences on the doped and dedoped surfaces for both chemical and electrochemical doping methods. Michaelis-Menten modelling suggests that the doped surface acts as an 'uncompetitive inhibitor' of kinesin. This work represents an investigation into the phenomenon of an electrically switchable surface exerting a moderating effect on the activity of an adsorbed protein that does not contain a bound, electroactive metal ion.

Pulsed laser triggered high speed microfluidic switch

Science.gov (United States)

Wu, Ting-Hsiang; Gao, Lanyu; Chen, Yue; Wei, Kenneth; Chiou, Pei-Yu

2008-10-01

We report a high-speed microfluidic switch capable of achieving a switching time of 10 μs. The switching mechanism is realized by exciting dynamic vapor bubbles with focused laser pulses in a microfluidic polydimethylsiloxane (PDMS) channel. The bubble expansion deforms the elastic PDMS channel wall and squeezes the adjacent sample channel to control its fluid and particle flows as captured by the time-resolved imaging system. A switching of polystyrene microspheres in a Y-shaped channel has also been demonstrated. This ultrafast laser triggered switching mechanism has the potential to advance the sorting speed of state-of-the-art microscale fluorescence activated cell sorting devices.

A fasting inducible switch modulates gluconeogenesis via activator/coactivator exchange

DEFF Research Database (Denmark)

Liu, Yi; Dentin, Renaud; Chen, Danica

2008-01-01

During early fasting, increases in skeletal muscle proteolysis liberate free amino acids for hepatic gluconeogenesis in response to pancreatic glucagon. Hepatic glucose output diminishes during the late protein-sparing phase of fasting, when ketone body production by the liver supplies compensatory...... expression through the dephosphorylation and nuclear shuttling of forkhead box O1 (FOXO1). Here we show that a fasting-inducible switch, consisting of the histone acetyltransferase p300 and the nutrient-sensing deacetylase sirtuin 1 (SIRT1), maintains energy balance in mice through the sequential induction...... of CRTC2 and FOXO1. After glucagon induction, CRTC2 stimulated gluconeogenic gene expression by an association with p300, which we show here is also activated by dephosphorylation at Ser 89 during fasting. In turn, p300 increased hepatic CRTC2 activity by acetylating it at Lys 628, a site that also...

Diverse Regular Employees and Non-regular Employment (Japanese)

OpenAIRE

MORISHIMA Motohiro

2011-01-01

Currently there are high expectations for the introduction of policies related to diverse regular employees. These policies are a response to the problem of disparities between regular and non-regular employees (part-time, temporary, contract and other non-regular employees) and will make it more likely that workers can balance work and their private lives while companies benefit from the advantages of regular employment. In this paper, I look at two issues that underlie this discussion. The ...

Activation of the Cph1-dependent MAP kinase signaling pathway induces white-opaque switching in Candida albicans.

Directory of Open Access Journals (Sweden)

Bernardo Ramírez-Zavala

Full Text Available Depending on the environmental conditions, the pathogenic yeast Candida albicans can undergo different developmental programs, which are controlled by dedicated transcription factors and upstream signaling pathways. C. albicans strains that are homozygous at the mating type locus can switch from the normal yeast form (white to an elongated cell type (opaque, which is the mating-competent form of this fungus. Both white and opaque cells use the Ste11-Hst7-Cek1/Cek2 MAP kinase signaling pathway to react to the presence of mating pheromone. However, while opaque cells employ the transcription factor Cph1 to induce the mating response, white cells recruit a different downstream transcription factor, Tec1, to promote the formation of a biofilm that facilitates mating of opaque cells in the population. The switch from the white to the opaque cell form is itself induced by environmental signals that result in the upregulation of the transcription factor Wor1, the master regulator of white-opaque switching. To get insight into the upstream signaling pathways controlling the switch, we expressed all C. albicans protein kinases from a tetracycline-inducible promoter in a switching-competent strain. Screening of this library of strains showed that a hyperactive form of Ste11 lacking its N-terminal domain (Ste11(ΔN467 efficiently stimulated white cells to switch to the opaque phase, a behavior that did not occur in response to pheromone. Ste11(ΔN467-induced switching specifically required the downstream MAP kinase Cek1 and its target transcription factor Cph1, but not Cek2 and Tec1, and forced expression of Cph1 also promoted white-opaque switching in a Wor1-dependent manner. Therefore, depending on the activation mechanism, components of the pheromone-responsive MAP kinase pathway can be reconnected to stimulate an alternative developmental program, switching of white cells to the mating-competent opaque phase.

Complementary resistive switching in BaTiO{sub 3}/NiO bilayer with opposite switching polarities

Energy Technology Data Exchange (ETDEWEB)

Li, Shuo [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Institut d’Electronique de Micro-électronique et de Nanotechnologie (IEMN), CNRS, Université des Sciences et Technologies de Lille, avenue Poincaré, BP 60069, 59652, Villeneuve d’Ascq cedex (France); Wei, Xianhua, E-mail: weixianhua@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Lei, Yao [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu 610054 (China); Yuan, Xincai [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Zeng, Huizhong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu 610054 (China)

2016-12-15

Graphical abstract: Au/BaTiO{sub 3}/NiO/Pt bilayer device shows complementary resistive switching (CRS) without electroforming which is mainly ascribed to anti-serial stack of two RRAM cells with bipolar behaviors. - Highlights: • Complementary resistive switching (CRS) has been investigated in Au/BaTiO{sub 3}/NiO/Pt by stacking the two elements with different switching types. • The realization of complementary resistive switching (CRS) is mainly ascribed to the anti-serial stack of two RRAM cells with bipolar behaviors. • Complementary resistive switching (CRS) in bilayer is effective to solve the sneak current problem briefly and economically. - Abstract: Resistive switching behaviors have been investigated in the Au/BaTiO{sub 3}/NiO/Pt structure by stacking the two elements with different switching types. The conducting atomic force microscope measurements on BaTiO{sub 3} thin films and NiO thin films suggest that with the same active resistive switching region, the switching polarities in the two semiconductors are opposite to each other. It is in agreement with the bipolar hysteresis I–V curves with opposite switching polarities for single-layer devices. The bilayer devices show complementary resistive switching (CRS) without electroforming and unipolar resistive switching (URS) after electroforming. The coexistence of CRS and URS is mainly ascribed to the co-effect of electric field and Joule heating mechanisms, indicating that changeable of resistance in this device is dominated by the redistribution of oxygen vacancies in BaTiO{sub 3} and the formation, disruption, restoration of conducting filaments in NiO. CRS in bilayer with opposite switching polarities is effective to solve the sneak current without the introduction of any selector elements or an additional metal electrode.

Efficiency Investigations of a 3 kW T-Type Inverter for Switching Frequencies up to 100 kHz

DEFF Research Database (Denmark)

Anthon, Alexander; Zhang, Zhe; Andersen, Michael A. E.

2014-01-01

This paper deals with a 3kW multilevel inverter used for PV applications. A comparison has been made based on simulations using IGBTs and SiC MOSFETs to see how much efficiency can be gained when SiC diodes are used. A prototype with the same IGBTs and SiC MOSFETs has been built but using regular...... soft-recovery Si diodes instead of SiC diodes. Efficiencies and switching transitions for different switching frequencies up to 100 kHz have been measured. Thermal investigations of both IGBTs and SiC MOSFETs have been conducted to analyze the feasibility of increased switching frequencies. When Si......C MOSFETs are used in combination with Si diodes, switching frequencies could be doubled achieving the same efficiencies than the IGBT converter....

Column Generation for Transmission Switching of Electricity Networks with Unit Commitment

DEFF Research Database (Denmark)

Villumsen, Jonas Christoffer; Philpott, Andy B.

2011-01-01

This paper presents the problem of finding the minimum cost dispatch and commitment of power generation units in a transmission network with active switching.We use the term active switching to denote the use of switches to optimize network topology in an operational context. We propose a Dantzig...

Reprogramming of the Ovarian Tumor Stroma by Activation of a Biomechanical ECM Switch

Science.gov (United States)

2015-07-01

which includes P130Cas. Phosphorylation of P130Cas within both its SH2 and SH3 domains facilitates protein-protein interactions that can...switch and Erk activation which may collectively promote stromal cell accumulation. While multiple protein kinases including members of the Src...family kinases as well as Abl are thought to contribute to the phosphorylation of P130Cas, the precise molecular mechanism by which cellular interactions

WE-FG-207B-03: Multi-Energy CT Reconstruction with Spatial Spectral Nonlocal Means Regularization

Energy Technology Data Exchange (ETDEWEB)

Li, B [University of Texas Southwestern Medical Center, Dallas, TX (United States); Southern Medical University, Guangzhou, Guangdong (China); Shen, C; Ouyang, L; Yang, M; Jiang, S; Jia, X [University of Texas Southwestern Medical Center, Dallas, TX (United States); Zhou, L [Southern Medical University, Guangzhou, Guangdong (China)

2016-06-15

Purpose: Multi-energy computed tomography (MECT) is an emerging application in medical imaging due to its ability of material differentiation and potential for molecular imaging. In MECT, image correlations at different spatial and channels exist. It is desirable to incorporate these correlations in reconstruction to improve image quality. For this purpose, this study proposes a MECT reconstruction technique that employes spatial spectral non-local means (ssNLM) regularization. Methods: We consider a kVp-switching scanning method in which source energy is rapidly switched during data acquisition. For each energy channel, this yields projection data acquired at a number of angles, whereas projection angles among channels are different. We formulate the reconstruction task as an optimziation problem. A least square term enfores data fidelity. A ssNLM term is used as regularization to encourage similarities among image patches at different spatial locations and channels. When comparing image patches at different channels, intensity difference were corrected by a transformation estimated via histogram equalization during the reconstruction process. Results: We tested our method in a simulation study with a NCAT phantom and an experimental study with a Gammex phantom. For comparison purpose, we also performed reconstructions using conjugate-gradient least square (CGLS) method and conventional NLM method that only considers spatial correlation in an image. ssNLM is able to better suppress streak artifacts. The streaks are along different projection directions in images at different channels. ssNLM discourages this dissimilarity and hence removes them. True image structures are preserved in this process. Measurements in regions of interests yield 1.1 to 3.2 and 1.5 to 1.8 times higher contrast to noise ratio than the NLM approach. Improvements over CGLS is even more profound due to lack of regularization in the CGLS method and hence amplified noise. Conclusion: The

Modular protein switches derived from antibody mimetic proteins.

Science.gov (United States)

Nicholes, N; Date, A; Beaujean, P; Hauk, P; Kanwar, M; Ostermeier, M

2016-02-01

Protein switches have potential applications as biosensors and selective protein therapeutics. Protein switches built by fusion of proteins with the prerequisite input and output functions are currently developed using an ad hoc process. A modular switch platform in which existing switches could be readily adapted to respond to any ligand would be advantageous. We investigated the feasibility of a modular protein switch platform based on fusions of the enzyme TEM-1 β-lactamase (BLA) with two different antibody mimetic proteins: designed ankyrin repeat proteins (DARPins) and monobodies. We created libraries of random insertions of the gene encoding BLA into genes encoding a DARPin or a monobody designed to bind maltose-binding protein (MBP). From these libraries, we used a genetic selection system for β-lactamase activity to identify genes that conferred MBP-dependent ampicillin resistance to Escherichia coli. Some of these selected genes encoded switch proteins whose enzymatic activity increased up to 14-fold in the presence of MBP. We next introduced mutations into the antibody mimetic domain of these switches that were known to cause binding to different ligands. To different degrees, introduction of the mutations resulted in switches with the desired specificity, illustrating the potential modularity of these platforms. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Predictive features of persistent activity emergence in regular spiking and intrinsic bursting model neurons.

Directory of Open Access Journals (Sweden)

Kyriaki Sidiropoulou

Full Text Available Proper functioning of working memory involves the expression of stimulus-selective persistent activity in pyramidal neurons of the prefrontal cortex (PFC, which refers to neural activity that persists for seconds beyond the end of the stimulus. The mechanisms which PFC pyramidal neurons use to discriminate between preferred vs. neutral inputs at the cellular level are largely unknown. Moreover, the presence of pyramidal cell subtypes with different firing patterns, such as regular spiking and intrinsic bursting, raises the question as to what their distinct role might be in persistent firing in the PFC. Here, we use a compartmental modeling approach to search for discriminatory features in the properties of incoming stimuli to a PFC pyramidal neuron and/or its response that signal which of these stimuli will result in persistent activity emergence. Furthermore, we use our modeling approach to study cell-type specific differences in persistent activity properties, via implementing a regular spiking (RS and an intrinsic bursting (IB model neuron. We identify synaptic location within the basal dendrites as a feature of stimulus selectivity. Specifically, persistent activity-inducing stimuli consist of activated synapses that are located more distally from the soma compared to non-inducing stimuli, in both model cells. In addition, the action potential (AP latency and the first few inter-spike-intervals of the neuronal response can be used to reliably detect inducing vs. non-inducing inputs, suggesting a potential mechanism by which downstream neurons can rapidly decode the upcoming emergence of persistent activity. While the two model neurons did not differ in the coding features of persistent activity emergence, the properties of persistent activity, such as the firing pattern and the duration of temporally-restricted persistent activity were distinct. Collectively, our results pinpoint to specific features of the neuronal response to a given

Regular physical activity in old age : effect on coronary heart disease risk factors and well-being

NARCIS (Netherlands)

Schuit, A.J.

1997-01-01

Background. Regular physical activity is considered an important aspect of a healthy lifestyle. It may improve fitness, physical competence and may lower the risk of coronary heart disease (CHD). However, until now, data on the

The effect of switch control site on computer skills of infants and toddlers.

Science.gov (United States)

Glickman, L; Deitz, J; Anson, D; Stewart, K

1996-01-01

The purpose of this study was to determine whether switch control site (hand vs. head) affects the age at which children can successfully activate a computer to play a cause-and-effect game. The sample consisted of 72 participants randomly divided into two groups (head switch and hand switch), with stratification for gender and age (9-11 months, 12-14 months, 15-17 months). All participants were typically developing. After a maximum of 5 min of training, each participant was given five opportunities to activate a Jelly Bean switch to play a computer game. Competency was defined as four to five successful switch activations. Most participants in the 9-month to 11-month age group could successfully use a hand switch to activate a computer, and for the 15-month to 17-month age group, 100% of the participants met with success. By contrast, in the head switch condition, approximately one third of the participants in each of the three age ranges were successful in activating the computer to play a cause-and-effect game. The findings from this study provide developmental guidelines for using switches (head vs. hand) to activate computers to play cause-and-effect games and suggest that the clinician may consider introducing basic computer and switch skills to children as young as 9 months of age. However, the clinician is cautioned that the head switch may be more difficult to master than the hand switch and that additional research involving children with motor impairments is needed.

Photo-stimulated resistive switching of ZnO nanorods

International Nuclear Information System (INIS)

Park, Jinjoo; Lee, Seunghyup; Yong, Kijung

2012-01-01

Resistive switching memory devices are promising candidates for emerging memory technologies because they yield outstanding device performance. Storage mechanisms for achieving high-density memory applications have been developed; however, so far many of them exhibit typical resistive switching behavior from the limited controlling conditions. In this study, we introduce photons as an unconventional stimulus for activating resistive switching behaviors. First, we compare the resistive switching behavior in light and dark conditions to describe how resistive switching memories can benefit from photons. Second, we drive the switching of resistance not by the electrical stimulus but only by the modulation of photon. ZnO nanorods were employed as a model system to demonstrate photo-stimulated resistive switching in high-surface-area nanomaterials, in which photo-driven surface states strongly affect their photoconductivity and resistance states. (paper)

Two Bistable Switches Govern M Phase Entry.

Science.gov (United States)

Mochida, Satoru; Rata, Scott; Hino, Hirotsugu; Nagai, Takeharu; Novák, Béla

2016-12-19

The abrupt and irreversible transition from interphase to M phase is essential to separate DNA replication from chromosome segregation. This transition requires the switch-like phosphorylation of hundreds of proteins by the cyclin-dependent kinase 1 (Cdk1):cyclin B (CycB) complex. Previous studies have ascribed these switch-like phosphorylations to the auto-activation of Cdk1:CycB through the removal of inhibitory phosphorylations on Cdk1-Tyr15 [1, 2]. The positive feedback in Cdk1 activation creates a bistable switch that makes mitotic commitment irreversible [2-4]. Here, we surprisingly find that Cdk1 auto-activation is dispensable for irreversible, switch-like mitotic entry due to a second mechanism, whereby Cdk1:CycB inhibits its counteracting phosphatase (PP2A:B55). We show that the PP2A:B55-inhibiting Greatwall (Gwl)-endosulfine (ENSA) pathway is both necessary and sufficient for switch-like phosphorylations of mitotic substrates. Using purified components of the Gwl-ENSA pathway in a reconstituted system, we found a sharp Cdk1 threshold for phosphorylation of a luminescent mitotic substrate. The Cdk1 threshold to induce mitotic phosphorylation is distinctly higher than the Cdk1 threshold required to maintain these phosphorylations-evidence for bistability. A combination of mathematical modeling and biochemical reconstitution show that the bistable behavior of the Gwl-ENSA pathway emerges from its mutual antagonism with PP2A:B55. Our results demonstrate that two interlinked bistable mechanisms provide a robust solution for irreversible and switch-like mitotic entry. Copyright © 2016 Elsevier Ltd. All rights reserved.

FPGA-based fully digital fast power switch fault detection and compensation for three-phase shunt active filters

Energy Technology Data Exchange (ETDEWEB)

Karimi, S.; Saadate, S. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, GREEN-UHP, CNRS UMR 7037 (France); Poure, P. [Laboratoire d' Instrumentation Electronique de Nancy, LIEN, EA 3440, France Nancy Universite - Universite Henri Poincare de Nancy I, BP 239, 54506 Vandoeuvre les Nancy cedex (France)

2008-11-15

This paper discusses the design, implementation, experimental validation and performances of a fully digital fast power switch fault detection and compensation for three-phase shunt active power filters. The approach introduced in this paper minimizes the time interval between the fault occurrence and its diagnosis. This paper demonstrates the possibility to detect a faulty switch of the active filter in less than 10 {mu}s by using simultaneously a ''time criterion'' and a ''voltage criterion''. In order to attain this fast detection time a FPGA (Field Programmable Gate Array) is used. The other feature introduced in this approach is that the control scheme used to compensate the current load harmonics and fault tolerant scheme are both programmed in only one FPGA. ''FPGA in the loop'' prototyping results and fully experimental results based on a real active power filter verify satisfactory performances of the proposed method. (author)

Microwave pulse generation by photoconductive switching

Energy Technology Data Exchange (ETDEWEB)

Pocha, M.D.; Druce, R.L.

1989-03-14

Laser activated photoconductive semiconductor switching shows significant potential for application in high power microwave generation. Primary advantages of this concept are: small size, light weight, ruggedness, precise timing and phasing by optical control, and the potential for high peak power in short pulses. Several concepts have been suggested for microwave generation using this technology. They generally fall into two categories (1) the frozen wave generator or (2) tuned cavity modulation, both of which require only fast closing switches. We have been exploring a third possibility requiring fast closing and opening switches, that is the direct modulation of the switch at microwave frequencies. Switches have been fabricated at LLNL using neutron irradiated Gallium Arsenide which exhibit response times as short as 50 ps at low voltages. We are in the process of performing high voltage tests. So far, we have been able to generate 2.4 kV pulses with approximately 340 ps response time (FWHM) using approximately a 200..mu..J optical pulse. Experiments are continuing to increase the voltage and improve the switching efficiency. 3 refs., 6 figs.

Microwave pulse generation by photoconductive switching

Science.gov (United States)

Pocha, M. D.; Druce, R. L.

1989-03-01

Laser activated photoconductive semiconductor switching shows significant potential for application in high power microwave generation. Primary advantages of this concept are: small size, light weight, ruggedness, precise timing and phasing by optical control, and the potential for high peak power in short pulses. Several concepts have been suggested for microwave generation using this technology. They generally fall into two categories: (1) the frozen wave generator, or (2) tuned cavity modulation, both of which require only fast closing switches. We have been exploring a third possibility requiring fast closing and opening switches, that is the direct modulation of the switch at microwave frequencies. Switches have been fabricated at LLNL using neutron irradiated Gallium Arsenide which exhibit response times as short as 50 ps at low voltages. We are in the process of performing high voltage tests. So far, we have been able to generate 2.4 kV pulses with approximately 340 ps response time (FWHM) using approximately a 200 microJ optical pulse. Experiments are continuing to increase the voltage and improve the switching efficiency.

Analysis of Switched-Rigid Floating Oscillator

Directory of Open Access Journals (Sweden)

Prabhakar R. Marur

2009-01-01

Full Text Available In explicit finite element simulations, a technique called deformable-to-rigid (D2R switching is used routinely to reduce the computation time. Using the D2R option, the deformable parts in the model can be switched to rigid and reverted back to deformable when needed during the analysis. The time of activation of D2R however influences the overall dynamics of the system being analyzed. In this paper, a theoretical basis for the selection of time of rigid switching based on system energy is established. A floating oscillator problem is investigated for this purpose and closed-form analytical expressions are derived for different phases in rigid switching. The analytical expressions are validated by comparing the theoretical results with numerical computations.

The Regularity and Irregularity of Travel: an Analysis of the Consistency of Travel Times Associated with Subsistence, Maintenance and Discretionary Activities

OpenAIRE

Longden, Thomas

2016-01-01

Regular and irregular travel patterns coincide with different underlying purposes of travel and days of the week. Within this paper, it is shown that the balance between subsistence (i.e. work) and discretionary (i.e. leisure) activities is related to differences in travel patterns and explains consistency across years. Using eight years of time use diary entries this paper finds that travel time related to subsistence activities tends to be regular and stable. In contrast, travel time associ...

Coordinate-invariant regularization

International Nuclear Information System (INIS)

Halpern, M.B.

1987-01-01

A general phase-space framework for coordinate-invariant regularization is given. The development is geometric, with all regularization contained in regularized DeWitt Superstructures on field deformations. Parallel development of invariant coordinate-space regularization is obtained by regularized functional integration of the momenta. As representative examples of the general formulation, the regularized general non-linear sigma model and regularized quantum gravity are discussed. copyright 1987 Academic Press, Inc

Fluid queues and regular variation

NARCIS (Netherlands)

O.J. Boxma (Onno)

1996-01-01

textabstractThis paper considers a fluid queueing system, fed by $N$ independent sources that alternate between silence and activity periods. We assume that the distribution of the activity periods of one or more sources is a regularly varying function of index $zeta$. We show that its fat tail

Proceedings of the switched power workshop

International Nuclear Information System (INIS)

Fernow, R.C.

1988-01-01

These proceedings contain most of the presentations given at a workshop on the current state of research in techniques for switched power acceleration. The proceedings are divided, as was the workshop itself, into two parts. Part 1, contains the latest results from a number of groups active in switched power research. The major topic here is a method for switching externally supplied power onto a transmission line. Advocates for vacuum photodiode switching, solid state switching, gas switching, and synthetic pulse generation are all presented. Other important areas of research described in this section concern: external electrical and laser pulsing systems; the properties of the created electromagnetic pulse; structures used for transporting the electromagnetic pulse to the region where the electron beam is located; and possible applications. Part 2 of the proceedings considers the problem of designing a high brightness electron gun using switched power as the power source. This is an important first step in demonstrating the usefulness of switched power techniques for accelerator physics. In addition such a gun could have immediate practical importance for advanced acceleration studies since the brightness could exceed that of present sources by several orders of magnitude. I would like to take this opportunity to thank Kathleen Tuohy and Patricia Tuttle for their assistance in organizing and running the workshop. Their tireless efforts contribute greatly to a very productive meeting

Factors Associated with Regular Physical Activity for the Prevention of Osteoporosis in Female Employees Alborz University of Medical Sciences: Application of Health Belief Model

Directory of Open Access Journals (Sweden)

E. Hatefnia

2016-05-01

Full Text Available Background: Osteoporosis is a metabolic bone disease and a growing global health problem that causes bones to thin and fragile. It is estimated that about two million people suffer from osteoporosis. According to the World Health Organization recommends regular physical activity is effective in preventing and while the results of some studies show about 65% of working women in Iran; do not get enough physical activity. This study aimed to determine factors associated with regular physical activity behavior for the prevention of osteoporosis in female employees Alborz University of Medical Sciences and was designed by HBM Methods: This study is a cross-sectional study involving 217 female university employees, all of whom were studied with the consent of the census. Tools for data collection questionnaire that included demographic questions, knowledge and questions based on health belief model structures that had done Validity and reliability. Data were analyzed using spss Edition19 and descriptive analytical statistics tests. Findings: The results show that regular physical activity was 37/8%. Idependent t-test showed a significant difference (P< 0/001 knowledge and self-efficacy between the two groups (with and without regular physical activity. Logistic regression analysis showed that knowledge and self-efficacy are significant predictor of Physical activity behavior. In this study, a significant association was found between the income and physical activity And the other factors such relationship wasnot found for physical activity. Conclusion: According to lack of regular physical activity and considering the relationship between knowledge and self-efficacy with physical activity, the need to addressing this issue through educational programming based on related factors. 

Creation of Principally New Generation of Switching Technique Elements (Reed Switches) with Nanostructured Contact Surfaces

Energy Technology Data Exchange (ETDEWEB)

Karabanov S M; Zeltser I A; Maizels R M; Moos E N; Arushanov K A, E-mail: zeltseria@rmcip.ru [Russia, Ryazan, 390027, Novaya Str., 51B, Ryazan Metal Ceramics Instrumentation Plant JSC (Russian Federation)

2011-04-01

The cycle of activities of the creation of principally new generation of reed switches with nanostructured contact surfaces was implemented. Experimental justification of the opportunity of reed switches creation with modified contact surface was given (instead of precious metals-based galvanic coating). Principally new technological process of modification of magnetically operated contacts contacting surfaces was developed, based on the usage of the ion-plasma methods of nanolayers and nanostructures forming having specified contact features.

The Application of High Temperature Superconducting Materials to Power Switches

CERN Document Server

March, S A; Ballarino, A

2009-01-01

Superconducting switches may find application in superconducting magnet systems that require energy extraction. Such superconducting switches could be bypass-switches that are operated in conjunction with a parallel resistor or dump-switches where all of the energy is dissipated in the switch itself. Bypass-switches are more suited to higher energy circuits as a portion of the energy can be dissipated in the external dump resistor. Dump- switches require less material and triggering energy as a lower switch resistance is needed to achieve the required total dump resistance. Both superconducting bypass-switches and superconducting dump-switches can be ther- mally activated. Switching times that are comparable to those obtained with mechanical bypass-switch systems can be achieved using a co-wound heater that is powered by a ca- pacitor discharge. Switches that have fast thermal diffusion times through the insulation can be modelled as a lumped system whereas those with slow thermal diffusion times were modelle...

Digital radiography using amorphous selenium: photoconductively activated switch (PAS) readout system.

Science.gov (United States)

Reznik, Nikita; Komljenovic, Philip T; Germann, Stephen; Rowlands, John A

2008-03-01

A new amorphous selenium (a-Se) digital radiography detector is introduced. The proposed detector generates a charge image in the a-Se layer in a conventional manner, which is stored on electrode pixels at the surface of the a-Se layer. A novel method, called photoconductively activated switch (PAS), is used to read out the latent x-ray charge image. The PAS readout method uses lateral photoconduction at the a-Se surface which is a revolutionary modification of the bulk photoinduced discharge (PID) methods. The PAS method addresses and eliminates the fundamental weaknesses of the PID methods--long readout times and high readout noise--while maintaining the structural simplicity and high resolution for which PID optical readout systems are noted. The photoconduction properties of the a-Se surface were investigated and the geometrical design for the electrode pixels for a PAS radiography system was determined. This design was implemented in a single pixel PAS evaluation system. The results show that the PAS x-ray induced output charge signal was reproducible and depended linearly on the x-ray exposure in the diagnostic exposure range. Furthermore, the readout was reasonably rapid (10 ms for pixel discharge). The proposed detector allows readout of half a pixel row at a time (odd pixels followed by even pixels), thus permitting the readout of a complete image in 30 s for a 40 cm x 40 cm detector with the potential of reducing that time by using greater readout light intensity. This demonstrates that a-Se based x-ray detectors using photoconductively activated switches could form a basis for a practical integrated digital radiography system.

Modifying attitude and intention toward regular physical activity using protection motivation theory: a randomized controlled trial.

Science.gov (United States)

Mirkarimi, Kamal; Eri, Maryam; Ghanbari, Mohammad R; Kabir, Mohammad J; Raeisi, Mojtaba; Ozouni-Davaji, Rahman B; Aryaie, Mohammad; Charkazi, Abdurrahman

2017-10-30

We were guided by the Protection Motivation Theory to test the motivational interviewing effects on attitude and intention of obese and overweight women to do regular physical activity. In a randomized controlled trial, we selected using convenience sampling 60 overweight and obese women attending health centres. The women were allocated to 2 groups of 30 receiving a standard weight-control programme or motivational interviewing. All constructs of the theory (perceived susceptibility, severity, self-efficacy and response efficacy) and all anthropometric characteristics (except body mass index) were significantly different between the groups at 3 study times. The strongest predictors of intention to do regular physical exercise were perceived response efficacy and attitude at 2- and 6-months follow-up. We showed that targeting motivational interviewing with an emphasis on Protection Motivation Theory constructs appeared to be beneficial for designing and developing appropriate intervention to improve physical activity status among women with overweight and obesity.

Charge transport through molecular switches

International Nuclear Information System (INIS)

Jan van der Molen, Sense; Liljeroth, Peter

2010-01-01

We review the fascinating research on charge transport through switchable molecules. In the past decade, detailed investigations have been performed on a great variety of molecular switches, including mechanically interlocked switches (rotaxanes and catenanes), redox-active molecules and photochromic switches (e.g. azobenzenes and diarylethenes). To probe these molecules, both individually and in self-assembled monolayers (SAMs), a broad set of methods have been developed. These range from low temperature scanning tunneling microscopy (STM) via two-terminal break junctions to larger scale SAM-based devices. It is generally found that the electronic coupling between molecules and electrodes has a profound influence on the properties of such molecular junctions. For example, an intrinsically switchable molecule may lose its functionality after it is contacted. Vice versa, switchable two-terminal devices may be created using passive molecules ('extrinsic switching'). Developing a detailed understanding of the relation between coupling and switchability will be of key importance for both future research and technology. (topical review)

Charge transport through molecular switches

Energy Technology Data Exchange (ETDEWEB)

Jan van der Molen, Sense [Kamerlingh Onnes Laboratorium, Leiden University, Niels Bohrweg 2, 2333 CA Leiden (Netherlands); Liljeroth, Peter, E-mail: molen@physics.leidenuniv.n [Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, University of Utrecht, PO Box 80000, 3508 TA Utrecht (Netherlands)

2010-04-07

We review the fascinating research on charge transport through switchable molecules. In the past decade, detailed investigations have been performed on a great variety of molecular switches, including mechanically interlocked switches (rotaxanes and catenanes), redox-active molecules and photochromic switches (e.g. azobenzenes and diarylethenes). To probe these molecules, both individually and in self-assembled monolayers (SAMs), a broad set of methods have been developed. These range from low temperature scanning tunneling microscopy (STM) via two-terminal break junctions to larger scale SAM-based devices. It is generally found that the electronic coupling between molecules and electrodes has a profound influence on the properties of such molecular junctions. For example, an intrinsically switchable molecule may lose its functionality after it is contacted. Vice versa, switchable two-terminal devices may be created using passive molecules ('extrinsic switching'). Developing a detailed understanding of the relation between coupling and switchability will be of key importance for both future research and technology. (topical review)

A Broadband Ultrathin Nonlinear Switching Metamaterial

Directory of Open Access Journals (Sweden)

E. Zarnousheh Farahani

2017-05-01

Full Text Available In this paper, an ultrathin planar nonlinear metamaterial slab is designed and simulated. Nonlinearity is provided through placing diodes in each metamaterial unit cell. The diodes are auto-biased and activated by an incident wave. The proposed structure represents a broadband switching property between two transmission and reflection states depending on the intensity of the incident wave. High permittivity values are presented creating a near zero effective impedance at low power states, around the second resonant mode of the structure unit cell; as the result, the incident wave is reflected. Increasing the incident power to the level which can activate the loaded diodes in the structure results in elimination of the resonance and consequently a drop in the permittivity values near the permeability one as well as a switch to the transmission state. A full wave as well as a nonlinear simulations are performed. An optimization method based on weed colonization is applied to the unit cell of the metamaterial slab to achieve the maximum switching bandwidth. The structure represents a 24% switching bandwidth of a 10 dB reduction in the reflection coefficient.

Switching between Domestic Market Activity, Export and FDI

DEFF Research Database (Denmark)

Hiller, Sanne; Yalcin, Erdal

-concentration trade-off with a stochastic productivity evolution, we analyze the transition dynamics between domestic market serving, exporting and FDI. We find that a stochastic productivity development generates hysteresis, and thereby confirm a general real option result. Market serving mode switching is driven...

Adaptability in IT Sourcing: The Impact of Switching Costs

Science.gov (United States)

Whitten, Dwayne

IT sourcing decisions are increasingly becoming more strategic than in the past. As this occurs, firms should maintain a strategy of adaptability in order to mitigate the risks inherently associated with sourcing. A major influence on the adaptability of a firm in the short- and long-term are the switching costs associated with moving an activity from one source to another. As switching costs increase, firms may be "locked in" to one source. Firms should therefore work to decrease the switching costs so that they are more able to move an activity from one source to another if the market changes or an outsourcing relationship sours. Three strategies are presented for lowering switching costs which will ultimately help increase adaptability.

Optical fiber switch

Science.gov (United States)

Early, James W.; Lester, Charles S.

2002-01-01

Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

A 13.56 MHz CMOS Active Rectifier With Switched-Offset and Compensated Biasing for Biomedical Wireless Power Transfer Systems.

Science.gov (United States)

Yan Lu; Wing-Hung Ki

2014-06-01

A full-wave active rectifier switching at 13.56 MHz with compensated bias current for a wide input range for wirelessly powered high-current biomedical implants is presented. The four diodes of a conventional passive rectifier are replaced by two cross-coupled PMOS transistors and two comparator- controlled NMOS switches to eliminate diode voltage drops such that high voltage conversion ratio and power conversion efficiency could be achieved even at low AC input amplitude |VAC|. The comparators are implemented with switched-offset biasing to compensate for the delays of active diodes and to eliminate multiple pulsing and reverse current. The proposed rectifier uses a modified CMOS peaking current source with bias current that is quasi-inversely proportional to the supply voltage to better control the reverse current over a wide AC input range (1.5 to 4 V). The rectifier was fabricated in a standard 0.35 μm CMOS N-well process with active area of 0.0651 mm(2). For the proposed rectifier measured at |VAC| = 3.0 V, the voltage conversion ratios are 0.89 and 0.93 for RL=500 Ω and 5 kΩ, respectively, and the measured power conversion efficiencies are 82.2% to 90.1% with |VAC| ranges from 1.5 to 4 V for RL=500 Ω.

Energy reversible switching from amorphous metal based nanoelectromechanical switch

KAUST Repository

Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

2013-01-01

We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young's modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young's modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

Energy reversible switching from amorphous metal based nanoelectromechanical switch

KAUST Repository

Mayet, Abdulilah M.

2013-08-01

We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

Action of Molecular Switches in GPCRs - Theoretical and Experimental Studies

Science.gov (United States)

Trzaskowski, B; Latek, D; Yuan, S; Ghoshdastider, U; Debinski, A; Filipek, S

2012-01-01

G protein coupled receptors (GPCRs), also called 7TM receptors, form a huge superfamily of membrane proteins that, upon activation by extracellular agonists, pass the signal to the cell interior. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. Biochemical and crystallographic methods together with molecular dynamics simulations and other theoretical techniques provided models of the receptor activation based on the action of so-called “molecular switches” buried in the receptor structure. They are changed by agonists but also by inverse agonists evoking an ensemble of activation states leading toward different activation pathways. Switches discovered so far include the ionic lock switch, the 3-7 lock switch, the tyrosine toggle switch linked with the nPxxy motif in TM7, and the transmission switch. The latter one was proposed instead of the tryptophan rotamer toggle switch because no change of the rotamer was observed in structures of activated receptors. The global toggle switch suggested earlier consisting of a vertical rigid motion of TM6, seems also to be implausible based on the recent crystal structures of GPCRs with agonists. Theoretical and experimental methods (crystallography, NMR, specific spectroscopic methods like FRET/BRET but also single-molecule-force-spectroscopy) are currently used to study the effect of ligands on the receptor structure, location of stable structural segments/domains of GPCRs, and to answer the still open question on how ligands are binding: either via ensemble of conformational receptor states or rather via induced fit mechanisms. On the other hand the structural investigations of homo- and heterodimers and higher oligomers revealed the mechanism of allosteric signal transmission and receptor

Fluid queues and regular variation

NARCIS (Netherlands)

Boxma, O.J.

1996-01-01

This paper considers a fluid queueing system, fed by N independent sources that alternate between silence and activity periods. We assume that the distribution of the activity periods of one or more sources is a regularly varying function of index ¿. We show that its fat tail gives rise to an even

Selection of regularization parameter for l1-regularized damage detection

Science.gov (United States)

Hou, Rongrong; Xia, Yong; Bao, Yuequan; Zhou, Xiaoqing

2018-06-01

The l1 regularization technique has been developed for structural health monitoring and damage detection through employing the sparsity condition of structural damage. The regularization parameter, which controls the trade-off between data fidelity and solution size of the regularization problem, exerts a crucial effect on the solution. However, the l1 regularization problem has no closed-form solution, and the regularization parameter is usually selected by experience. This study proposes two strategies of selecting the regularization parameter for the l1-regularized damage detection problem. The first method utilizes the residual and solution norms of the optimization problem and ensures that they are both small. The other method is based on the discrepancy principle, which requires that the variance of the discrepancy between the calculated and measured responses is close to the variance of the measurement noise. The two methods are applied to a cantilever beam and a three-story frame. A range of the regularization parameter, rather than one single value, can be determined. When the regularization parameter in this range is selected, the damage can be accurately identified even for multiple damage scenarios. This range also indicates the sensitivity degree of the damage identification problem to the regularization parameter.

Regular physical activity attenuates the blood pressure response to public speaking and delays the development of hypertension.

Science.gov (United States)

Palatini, Paolo; Bratti, Paolo; Palomba, Daniela; Saladini, Francesca; Zanatta, Nello; Maraglino, Giuseppe

2010-06-01

The objective of this study was to investigate the effect of regular physical activity on the haemodynamic response to public speaking and to evaluate the long-term effect of exercise on development of hypertension. We assessed 75 sedentary and 44 active participants screened for stage 1 hypertension with consistent activity habits and 63 normotensive individuals as control. The blood pressure (BP) response to public speaking was assessed with beat-to-beat noninvasive recording. Definition of incident hypertension was based either on clinic or 24-h BP measurement. The BP response to public speaking was greater in the hypertensive than the normotensive participants (P=0.018/0.009). Among the former, sedentary participants showed increased BP reactivity to the speech test (45.2+/-22.6/22.2+/-11.5mmHg, Ppublic speaking into the Cox model influenced the strength of the association only marginally [hazard ratio=0.55 (95% CI 0.30-0.97) and hazard ratio=0.59 (95% CI 0.36-0.99), respectively]. Regular physical activity attenuates the BP reaction to psychosocial stressors. However, this mechanism seems to be only partially responsible for the long-term effect of exercise on BP.

Activation barrier scaling and crossover for noise-induced switching in micromechanical parametric oscillators.

Science.gov (United States)

Chan, H B; Stambaugh, C

2007-08-10

We explore fluctuation-induced switching in parametrically driven micromechanical torsional oscillators. The oscillators possess one, two, or three stable attractors depending on the modulation frequency. Noise induces transitions between the coexisting attractors. Near the bifurcation points, the activation barriers are found to have a power law dependence on frequency detuning with critical exponents that are in agreement with predicted universal scaling relationships. At large detuning, we observe a crossover to a different power law dependence with an exponent that is device specific.

Which Socio-Ecological Factors Associate with a Switch to or Maintenance of Active and Passive Transport during the Transition from Primary to Secondary School?

Science.gov (United States)

Vanwolleghem, Griet; Van Dyck, Delfien; De Meester, Femke; De Bourdeaudhuij, Ilse; Cardon, Greet; Gheysen, Freja

2016-01-01

The aim was to investigate which individual, psychosocial and physical neighborhood environmental factors associate with children's switch to or maintenance of active/passive transport to school and to leisure time destinations during the transition from primary to secondary school. Children (n = 313) filled out a questionnaire in the last year of primary school and 2 years later to assess socio-demographic characteristics and self-reported transport. One of their parents completed a questionnaire to assess parental perceptions of psychosocial and physical neighborhood environmental factors. The increase of the home-school distance was significantly associated with children's switch to or maintenance of passive transport to school compared to a switch to (OR = 0.81; p = 0.03) and maintenance (OR = 0.87; p = 0.03) of active transport to school. Low SES was associated with children's switch to active transport to school compared to maintenance of active transport (OR = 3.67; p = 0.07). For transport to leisure time destinations, other factors such as parental perceived neighborhood safety from traffic and crime (OR = 2.78; p = 0.004), a positive social norm (OR = 1.49; p = 0.08), positive attitudes (OR = 1.39; p = 0.08) (i.e. more benefits, less barriers) towards their children's physical activity and poor walking/cycling facilities in the neighborhood (OR = 0.70; p = 0.06) were associated with children's maintenance of active transport to leisure time destinations compared to a switch to or maintenance of passive transport. This longitudinal study can give directions for interventions promoting children's active transport during the transition to secondary school. It is necessary to promote different possibilities at primary school for children to use active transport when going to secondary school. Walking/cycling a part of the home-school trip can be a possible solution for children who will be living at non-feasible distances from secondary school. Providing safe

On power consumption issues in FIR filters with application to communication receivers: complexity, word length, and switching activity

Energy Technology Data Exchange (ETDEWEB)

Havashki, Asghar

2009-10-15

channel estimation must be upheld, in particular at medium-to-high Channel Signal to Noise Ratios (CSNR). Furthermore, reducing the power consumption through word-length optimization, when realizing such estimators, is an attractive approach. Due to the characteristics of the input signal to such estimators, a special treatment of channel estimation error due to quantization of estimator filter coefficients is needed. In this thesis we investigate the impact of finite coefficient word length on channel estimator performance. A theoretical analysis of the increase in channel estimation error due to quantization of estimator coefficients is performed, and the behavior of this error in different fading environments and for different filter orders is studied. The power consumed in a channel estimator is also influenced by the switching activity in the input signal of the estimator. Characterizing the switching activity in the input signal, including how this activity changes in different environments, e.g., in the presence of noise, is a subject of the work performed in this thesis. In this study we give an expression for direct calculation of the correlation coefficient for the most significant bit in a signal, using the word-level correlation coefficient. We also derive expressions for accurately calculating the variance and word-level correlation coefficient for a correlated signal, when an additional noise of a given variance is added to the signal. This can be used to estimate the bit-level switching activity in a signal in the presence of noise, based on the Dual Bit Type (DBT) method. The impact the additional noise has on the switching activity of a correlated signal has also been studied. These results make it possible for a designer to model the actual input switching activity in different real life noisy environments, enabling realistic power consumption estimation. A study on switching activity reduction in estimator filters using a coefficient reordering method

Pseudospark switches

International Nuclear Information System (INIS)

Billault, P.; Riege, H.; Gulik, M. van; Boggasch, E.; Frank, K.

1987-01-01

The pseudospark discharge is bound to a geometrical structure which is particularly well suited for switching high currents and voltages at high power levels. This type of discharge offers the potential for improvement in essentially all areas of switching operation: peak current and current density, current rise, stand-off voltage, reverse current capability, cathode life, and forward drop. The first pseudospark switch was built at CERN at 1981. Since then, the basic switching characteristics of pseudospark chambers have been studied in detail. The main feature of a pseudospark switch is the confinement of the discharge plasma to the device axis. The current transition to the hollow electrodes is spread over a rather large surface area. Another essential feature is the easy and precise triggering of the pseudospark switch from the interior of the hollow electrodes, relatively far from the main discharge gap. Nanosecond delay and jitter values can be achieved with trigger energies of less than 0.1 mJ, although cathode heating is not required. Pseudospark gaps may cover a wide range of high-voltage, high-current, and high-pulse-power switching at repetition rates of many kilohertz. This report reviews the basic researh on pseudospark switches which has been going on at CERN. So far, applications have been developed in the range of thyratron-like medium-power switches at typically 20 to 40 kV and 0.5 to 10 kA. High-current pseudospark switches have been built for a high-power 20 kJ pulse generator which is being used for long-term tests of plasma lenses developed for the future CERN Antiproton Collector (ACOL). The high-current switches have operated for several hundred thousand shots, with 20 to 50 ns jitter at 16 kV charging voltage and more than 100 kA peak current amplitude. (orig.)

Synchronization Between Two Different Switched Chaotic Systems By Switching Control

Directory of Open Access Journals (Sweden)

Du Li Ming

2016-01-01

Full Text Available This paper is concerned with the synchronization problem of two different switched chaotic systems, considering the general case that the master-slave switched chaotic systems have uncertainties. Two basic problems are considered: one is projective synchronization of switched chaotic systems under arbitrary switching; the other is projective synchronization of switched chaotic systems by design of switching when synchronization cannot achieved by using any subsystems alone. For the two problems, common Lyapunov function method and multiple Lyapunov function method are used respectively, an adaptive control scheme has been presented, some sufficient synchronization conditions are attainted, and the switching signal is designed. Finally, the numerical simulation is provide to show the effectiveness of our method.

Exciter switch

Science.gov (United States)

Mcpeak, W. L.

1975-01-01

A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

Photonics in switching: Architectures, systems and enabling technologies

DEFF Research Database (Denmark)

Raffaelli, C.; Vlachos, K.; Andriolli, N.

2008-01-01

This paper describes recent research activities and results in the area of photonic switching carried out within the Virtual Department on Switching (VDS) of the European e-Photon/ONe Network of Excellence. Contributions from outstanding European research groups in this field are collected to offer...

Active high-power RF pulse compression using optically switched resonant delay lines

International Nuclear Information System (INIS)

Tantawi, S.G.; Ruth, R.D.; Vlieks, A.E.

1996-11-01

The authors present the design and a proof of principle experimental results of an optically controlled high power rf pulse compression system. The design should, in principle, handle few hundreds of Megawatts of power at X-band. The system is based on the switched resonant delay line theory. It employs resonant delay lines as a means of storing rf energy. The coupling to the lines is optimized for maximum energy storage during the charging phase. To discharge the lines, a high power microwave switch increases the coupling to the lines just before the start of the output pulse. The high power microwave switch, required for this system, is realized using optical excitation of an electron-hole plasma layer on the surface of a pure silicon wafer. The switch is designed to operate in the TE 01 mode in a circular waveguide to avoid the edge effects present at the interface between the silicon wafer and the supporting waveguide; thus, enhancing its power handling capability

A Switch Is Not a Switch: Syntactically-Driven Bilingual Language Control

Science.gov (United States)

Gollan, Tamar H.; Goldrick, Matthew

2018-01-01

The current study investigated the possibility that language switches could be relatively automatically triggered by context. "Single-word switches," in which bilinguals switched languages on a single word in midsentence and then immediately switched back, were contrasted with more complete "whole-language switches," in which…

Switching Phenomena in a System with No Switches

Science.gov (United States)

Preis, Tobias; Stanley, H. Eugene

2010-02-01

It is widely believed that switching phenomena require switches, but this is actually not true. For an intriguing variety of switching phenomena in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. For example, financial market fluctuations are characterized by many abrupt switchings creating increasing trends ("bubble formation") and decreasing trends ("financial collapse"). Such switching occurs on time scales ranging from macroscopic bubbles persisting for hundreds of days to microscopic bubbles persisting only for a few seconds. We analyze a database containing 13,991,275 German DAX Future transactions recorded with a time resolution of 10 msec. For comparison, a database providing 2,592,531 of all S&P500 daily closing prices is used. We ask whether these ubiquitous switching phenomena have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the volatility after each switching occurs. We interpret our findings as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in transaction volume and time intervals between trades. We show that these financial market switching processes have properties similar to those of phase transitions. We suggest that the well-known catastrophic bubbles that occur on large time scales—such as the most recent financial crisis—are no outliers but single dramatic representatives caused by the switching between upward and downward trends on time scales varying over nine orders of magnitude from very large (≈102 days) down to very small (≈10 ms).

Cross-cultural comparison of lack of regular physical activity among college students: Universal versus transversal.

Science.gov (United States)

Seo, Dong-Chul; Torabi, Mohammad R; Jiang, Nan; Fernandez-Rojas, Xinia; Park, Bock-Hee

2009-01-01

This study examined cultural influence on personal and behavioral correlates of lack of regular physical activity (PA) among college students in four countries, i.e., the United States, Costa Rica, India, and South Korea. Public universities were randomly chosen among the four countries. A total of 4,685 students participated in the study during the 2006-2007 academic year with a response rate of 90.1%. The vast majority of the questions on the instrument were adopted from the Youth Risk Behavior Survey and the Behavioral Risk Factor Surveillance System questionnaires. The instrument was translated into Spanish and Korean and then back-translated into English to check accuracy of the translation. Low fruit consumption was a culture-universal predictor of lack of regular PA. Gender, perceived body weight, vegetable consumption, and cigarette smoking were culture-specific predictors, indicating PA might be a transversal value. Body mass index, binge drinking, and TV/video watching were not associated with lack of regular PA in any of the four countries. While PA is valued across different segments of many cultures, given the several culture-specific predictors, PA appears to be more transversal than universal. Therefore, culturally sensitive interventions are necessary to promote PA among young adults.

EDITORIAL: Molecular switches at surfaces Molecular switches at surfaces

Science.gov (United States)

Weinelt, Martin; von Oppen, Felix

2012-10-01

In nature, molecules exploit interaction with their environment to realize complex functionalities on the nanometer length scale. Physical, chemical and/or biological specificity is frequently achieved by the switching of molecules between microscopically different states. Paradigmatic examples are the energy production in proton pumps of bacteria or the signal conversion in human vision, which rely on switching molecules between different configurations or conformations by external stimuli. The remarkable reproducibility and unparalleled fatigue resistance of these natural processes makes it highly desirable to emulate nature and develop artificial systems with molecular functionalities. A promising avenue towards this goal is to anchor the molecular switches at surfaces, offering new pathways to control their functional properties, to apply electrical contacts, or to integrate switches into larger systems. Anchoring at surfaces allows one to access the full range from individual molecular switches to self-assembled monolayers of well-defined geometry and to customize the coupling between molecules and substrate or between adsorbed molecules. Progress in this field requires both synthesis and preparation of appropriate molecular systems and control over suitable external stimuli, such as light, heat, or electrical currents. To optimize switching and generate function, it is essential to unravel the geometric structure, the electronic properties and the dynamic interactions of the molecular switches on surfaces. This special section, Molecular Switches at Surfaces, collects 17 contributions describing different aspects of this research field. They analyze elementary processes, both in single molecules and in ensembles of molecules, which involve molecular switching and concomitant changes of optical, electronic, or magnetic properties. Two topical reviews summarize the current status, including both challenges and achievements in the field of molecular switches on

Switching away from pipotiazine palmitate: a naturalistic study.

Science.gov (United States)

Mustafa, Feras Ali

2017-01-01

In March 2015, pipotiazine palmitate depot antipsychotic was globally withdrawn due to the shortage of its active ingredient. Thus, all patients receiving this medication had to be switched to an alternative antipsychotic drug. In this study we set to evaluate the process of switching away from pipotiazine palmitate within our clinical service, and its impact on hospitalization. Demographic and clinical data on patients who were receiving pipotiazine palmitate in Northamptonshire at the time of its withdrawal were anonymously extracted from their electronic records and analyzed using descriptive statistics. A total of 17 patients were switched away from pipotiazine palmitate at the time of its withdrawal, all of whom had a prior history of nonadherence with oral treatment. A total of 14 patients were switched to another depot antipsychotic drug, while three patients chose an oral alternative which they subsequently discontinued resulting in relapse and hospitalization. There was a five-fold increase in mean hospitalization among patients who completed a year after the switch. Switching away from pipotiazine palmitate was associated with significant clinical deterioration in patients who switched to an oral antipsychotic, whereas most patients who switched to another depot treatment maintained stability. Clinicians should exercise caution when switching patients with schizophrenia away from depot antipsychotic drugs, especially in cases of patients with a history of treatment nonadherence who prefer to switch to oral antipsychotics.

Effects of high-fat diets with different carbohydrate-to-protein ratios on energy homeostasis in rats with impaired brain melanocortin receptor activity

NARCIS (Netherlands)

Morens, C.; Keijzer, M.; de Vries, K.; Scheurink, A; van Dijk, G

Changes in dietary macronutrient composition and/or central nervous system neuronal activity can underlie obesity and disturbed fuel homeostasis. We examined whether switching rats from a diet with high carbohydrate content (HC; i.e., regular chow) to diets with either high fat (HF) or high fat/high

Regular physical activity has differential association with reduced obesity among diverse youth in the United States.

Science.gov (United States)

Fradkin, Chris; Wallander, Jan L; Elliott, Marc N; Cuccaro, Paula; Schuster, Mark A

2016-08-01

This study examined whether daily or almost daily lower-intensity physical activity was associated with reduced obesity, among 4824 African American, Hispanic, and White youth assessed in fifth and seventh grades. Regular lower-intensity physical activity was associated with reduced obesity only among Hispanic and White males and only in seventh grade, and not among youth in fifth grade, females, or African American males or females. Findings from this study suggest that the reduced obesity risk generally attributed to physical activity may not be consistent across racial/ethnic and gender groups of early adolescents. © The Author(s) 2014.

The structure of Plasmodium falciparum serine hydroxymethyltransferase reveals a novel redox switch that regulates its activities

Energy Technology Data Exchange (ETDEWEB)

Chitnumsub, Penchit; Ittarat, Wanwipa; Jaruwat, Aritsara; Noytanom, Krittikar [National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Amornwatcharapong, Watcharee [Mahidol University, Bangkok (Thailand); Pornthanakasem, Wichai [National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Chaiyen, Pimchai [Mahidol University, Bangkok (Thailand); Yuthavong, Yongyuth; Leartsakulpanich, Ubolsree [National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120 (Thailand)

2014-06-01

The crystal structure of P. falciparum SHMT revealed snapshots of an intriguing disulfide/sulfhydryl switch controlling the functional activity. Plasmodium falciparum serine hydroxymethyltransferase (PfSHMT), an enzyme in the dTMP synthesis cycle, is an antimalarial target because inhibition of its expression or function has been shown to be lethal to the parasite. As the wild-type enzyme could not be crystallized, protein engineering of residues on the surface was carried out. The surface-engineered mutant PfSHMT-F292E was successfully crystallized and its structure was determined at 3 Å resolution. The PfSHMT-F292E structure is a good representation of PfSHMT as this variant revealed biochemical properties similar to those of the wild type. Although the overall structure of PfSHMT is similar to those of other SHMTs, unique features including the presence of two loops and a distinctive cysteine pair formed by Cys125 and Cys364 in the tetrahydrofolate (THF) substrate binding pocket were identified. These structural characteristics have never been reported in other SHMTs. Biochemical characterization and mutation analysis of these two residues confirm that they act as a disulfide/sulfhydryl switch to regulate the THF-dependent catalytic function of the enzyme. This redox switch is not present in the human enzyme, in which the cysteine pair is absent. The data reported here can be further exploited as a new strategy to specifically disrupt the activity of the parasite enzyme without interfering with the function of the human enzyme.

The structure of Plasmodium falciparum serine hydroxymethyltransferase reveals a novel redox switch that regulates its activities

International Nuclear Information System (INIS)

Chitnumsub, Penchit; Ittarat, Wanwipa; Jaruwat, Aritsara; Noytanom, Krittikar; Amornwatcharapong, Watcharee; Pornthanakasem, Wichai; Chaiyen, Pimchai; Yuthavong, Yongyuth; Leartsakulpanich, Ubolsree

2014-01-01

The crystal structure of P. falciparum SHMT revealed snapshots of an intriguing disulfide/sulfhydryl switch controlling the functional activity. Plasmodium falciparum serine hydroxymethyltransferase (PfSHMT), an enzyme in the dTMP synthesis cycle, is an antimalarial target because inhibition of its expression or function has been shown to be lethal to the parasite. As the wild-type enzyme could not be crystallized, protein engineering of residues on the surface was carried out. The surface-engineered mutant PfSHMT-F292E was successfully crystallized and its structure was determined at 3 Å resolution. The PfSHMT-F292E structure is a good representation of PfSHMT as this variant revealed biochemical properties similar to those of the wild type. Although the overall structure of PfSHMT is similar to those of other SHMTs, unique features including the presence of two loops and a distinctive cysteine pair formed by Cys125 and Cys364 in the tetrahydrofolate (THF) substrate binding pocket were identified. These structural characteristics have never been reported in other SHMTs. Biochemical characterization and mutation analysis of these two residues confirm that they act as a disulfide/sulfhydryl switch to regulate the THF-dependent catalytic function of the enzyme. This redox switch is not present in the human enzyme, in which the cysteine pair is absent. The data reported here can be further exploited as a new strategy to specifically disrupt the activity of the parasite enzyme without interfering with the function of the human enzyme

Inherent stochasticity of superconductor-resistor switching behavior in nanowires.

Science.gov (United States)

Shah, Nayana; Pekker, David; Goldbart, Paul M

2008-11-14

We study the stochastic dynamics of superconductive-resistive switching in hysteretic current-biased superconducting nanowires undergoing phase-slip fluctuations. We evaluate the mean switching time using the master-equation formalism, and hence obtain the distribution of switching currents. We find that as the temperature is reduced this distribution initially broadens; only at lower temperatures does it show the narrowing with cooling naively expected for phase slips that are thermally activated. We also find that although several phase-slip events are generally necessary to induce switching, there is an experimentally accessible regime of temperatures and currents for which just one single phase-slip event is sufficient to induce switching, via the local heating it causes.

Coupling regularizes individual units in noisy populations

International Nuclear Information System (INIS)

Ly Cheng; Ermentrout, G. Bard

2010-01-01

The regularity of a noisy system can modulate in various ways. It is well known that coupling in a population can lower the variability of the entire network; the collective activity is more regular. Here, we show that diffusive (reciprocal) coupling of two simple Ornstein-Uhlenbeck (O-U) processes can regularize the individual, even when it is coupled to a noisier process. In cellular networks, the regularity of individual cells is important when a select few play a significant role. The regularizing effect of coupling surprisingly applies also to general nonlinear noisy oscillators. However, unlike with the O-U process, coupling-induced regularity is robust to different kinds of coupling. With two coupled noisy oscillators, we derive an asymptotic formula assuming weak noise and coupling for the variance of the period (i.e., spike times) that accurately captures this effect. Moreover, we find that reciprocal coupling can regularize the individual period of higher dimensional oscillators such as the Morris-Lecar and Brusselator models, even when coupled to noisier oscillators. Coupling can have a counterintuitive and beneficial effect on noisy systems. These results have implications for the role of connectivity with noisy oscillators and the modulation of variability of individual oscillators.

Transient-Switch-Signal Suppressor

Science.gov (United States)

Bozeman, Richard J., Jr.

1995-01-01

Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.

High voltage disconnect switch position monitoring

Energy Technology Data Exchange (ETDEWEB)

Crampton, S W

1983-08-01

Unreliable position indication on high-voltage (HV) disconnect switches can result in equipment damage worth many times the cost of a disconnect switch. The benefits and limitations of a number of possible methods of reliably monitoring HV disconnect switches are assessed. Several methods of powering active devices at HV are noted. It is concluded that the most reliable way of monitoring switch position at reasonable cost would use a passive hermetically-sealed blade-position sensor located at HV, with a fibre-optic link between HV and ground. Separate sensors would be used for open and closed position indication. For maximum reliability the fibre-optic link would continue into the relay building. A passive magnetically actuated fibre-optic sensor has been built which demonstrates the feasibility of the concept. The sensor monitors blade position relative to the jaws in three dimensions with high resolution. A design for an improved passive magneto-optic sensor has significantly lower optical losses, allowing a single fibre-optic loop and 3 sensors to monitor closure of all phases of a disconnect switch. A similar loop would monitor switch opening. The improved sensor has a solid copper housing to provide greater immunity to fault currents, and to protect it from the environment and from physical damage. Two methods of providing a protected path for fibre-optics passing from HV to ground are proposed, one using a hollow porcelain switch-support insulator and the other using an additional small-diameter polymer insulator with optical fibres imbedded in its fibreglass core. A number of improvements are recommended which can be made to existing switches to increase their reliability. 16 refs., 13 figs., 1 tab.

Energy utilization associated with regular activity breaks and continuous physical activity: A randomized crossover trial.

Science.gov (United States)

Fenemor, S P; Homer, A R; Perry, T L; Skeaff, C M; Peddie, M C; Rehrer, N J

2018-06-01

To quantify and compare energy utilization associated with prolonged sitting alone, or interrupted with regular activity breaks and/or an additional bout of continuous physical activity. Thirty six adults (11 males, BMI 24.1 ± 4.6) completed four interventions: (1) prolonged sitting (SIT), (2) sitting with 2-min of walking every 30 min (RAB), (3) prolonged sitting with 30-min of continuous walking at the end of the day (SIT + PA), (4) a combination of the activities in (2) and (3) above (RAB + PA). All walking was at a speed and incline corresponding to 60% V̇O 2max . Energy utilization over 7 h for each intervention was estimated using indirect calorimetry. Compared to SIT, SIT + PA increased total energy utilization by 709 kJ (95% CI 485-933 kJ), RAB by 863 kJ (95% CI 638-1088 kJ), and RAB + PA by 1752 kJ (95% CI 1527-1927 kJ) (all p energy utilization between SIT + PA and RAB, however, post-physical activity energy utilization in RAB was 632 kJ greater than SIT + PA (95% CI 561-704 kJ; p energy utilization compared to a single bout of continuous activity; however the total energy utilization is similar. Combining activity breaks with a longer continuous bout of activity will further enhance energy utilization, and in the longer term, may positively affect weight management of a greater magnitude than either activity pattern performed alone. ANZCTR12614000624684. Copyright © 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Cognitive, emotional, and social benefits of regular musical activities in early dementia: randomized controlled study.

Science.gov (United States)

Särkämö, Teppo; Tervaniemi, Mari; Laitinen, Sari; Numminen, Ava; Kurki, Merja; Johnson, Julene K; Rantanen, Pekka

2014-08-01

During aging, musical activities can help maintain physical and mental health and cognitive abilities, but their rehabilitative use has not been systematically explored in persons with dementia (PWDs). Our aim was to determine the efficacy of a novel music intervention based on coaching the caregivers of PWDs to use either singing or music listening regularly as a part of everyday care. Eighty-nine PWD-caregiver dyads were randomized to a 10-week singing coaching group (n = 30), a 10-week music listening coaching group (n = 29), or a usual care control group (n = 30). The coaching sessions consisted primarily of singing/listening familiar songs coupled occasionally with vocal exercises and rhythmic movements (singing group) and reminiscence and discussions (music listening group). In addition, the intervention included regular musical exercises at home. All PWDs underwent an extensive neuropsychological assessment, which included cognitive tests, as well as mood and quality of life (QOL) scales, before and after the intervention period and 6 months later. In addition, the psychological well-being of family members was repeatedly assessed with questionnaires. Compared with usual care, both singing and music listening improved mood, orientation, and remote episodic memory and to a lesser extent, also attention and executive function and general cognition. Singing also enhanced short-term and working memory and caregiver well-being, whereas music listening had a positive effect on QOL. Regular musical leisure activities can have long-term cognitive, emotional, and social benefits in mild/moderate dementia and could therefore be utilized in dementia care and rehabilitation. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The neural basis of task switching changes with skill acquisition

Directory of Open Access Journals (Sweden)

Koji eJimura

2014-05-01

Full Text Available Learning novel skills involves reorganization and optimization of cognitive processing involving a broad network of brain regions. Previous work has shown asymmetric costs of switching to a well-trained task versus a poorly-trained task, but the neural basis of these differential switch costs is unclear. The current study examined the neural signature of task switching in the context of acquisition of new skill. Human participants alternated randomly between a novel visual task (mirror-reversed word reading and a highly practiced one (plain word reading, allowing the isolation of task switching and skill set maintenance. Two scan sessions were separated by two weeks, with behavioral training on the mirror reading task in between the two sessions. Broad cortical regions, including bilateral prefrontal, parietal, and extrastriate cortices, showed decreased activity associated with learning of the mirror reading skill. In contrast, learning to switch to the novel skill was associated with decreased activity in a focal subcortical region in the dorsal striatum. Switching to the highly practiced task was associated with a non-overlapping set of regions, suggesting substantial differences in the neural substrates of switching as a function of task skill. Searchlight multivariate pattern analysis also revealed that learning was associated with decreased pattern information for mirror versus plain reading tasks in fronto-parietal regions. Inferior frontal junction and posterior parietal cortex showed a joint effect of univariate activation and pattern information. These results suggest distinct learning mechanisms task performance and executive control as a function of learning.

Design of a bistable switch to control cellular uptake.

Science.gov (United States)

Oyarzún, Diego A; Chaves, Madalena

2015-12-06

Bistable switches are widely used in synthetic biology to trigger cellular functions in response to environmental signals. All bistable switches developed so far, however, control the expression of target genes without access to other layers of the cellular machinery. Here, we propose a bistable switch to control the rate at which cells take up a metabolite from the environment. An uptake switch provides a new interface to command metabolic activity from the extracellular space and has great potential as a building block in more complex circuits that coordinate pathway activity across cell cultures, allocate metabolic tasks among different strains or require cell-to-cell communication with metabolic signals. Inspired by uptake systems found in nature, we propose to couple metabolite import and utilization with a genetic circuit under feedback regulation. Using mathematical models and analysis, we determined the circuit architectures that produce bistability and obtained their design space for bistability in terms of experimentally tuneable parameters. We found an activation-repression architecture to be the most robust switch because it displays bistability for the largest range of design parameters and requires little fine-tuning of the promoters' response curves. Our analytic results are based on on-off approximations of promoter activity and are in excellent qualitative agreement with simulations of more realistic models. With further analysis and simulation, we established conditions to maximize the parameter design space and to produce bimodal phenotypes via hysteresis and cell-to-cell variability. Our results highlight how mathematical analysis can drive the discovery of new circuits for synthetic biology, as the proposed circuit has all the hallmarks of a toggle switch and stands as a promising design to control metabolic phenotypes across cell cultures. © 2015 The Author(s).

Optical Switching for Dynamic Distribution of Wireless-over-Fiber Signals

DEFF Research Database (Denmark)

Rodes Lopez, Guillermo Arturo; Vegas Olmos, Juan José; Karinou, Fotini

2012-01-01

In this paper, we report on an experimental validation of dynamic distribution of wireless-over-fiber by employing optical switching using semiconductor optical amplifiers; the rest of the network was designed according to the channel distribution over the optical spectra required by the optical...... switch. An experimental validation was also conducted. The experiment consists of a four wavelength division multiplexed (WDM) channel system operating on a WiMax frequency band, and employing an orthogonal frequency-division multiplexing (OFDM) modulation at 625 Mbit/s per channel, transmission...... of the data over 20 km of optical fiber, and active switching in a one-by-sixteen active optical switch. The results show a negligible power penalty on each channel, for both the best and the worst case in terms of inter-channel crosstalk....

Behavioral plasticity through the modulation of switch neurons.

Science.gov (United States)

Vassiliades, Vassilis; Christodoulou, Chris

2016-02-01

A central question in artificial intelligence is how to design agents capable of switching between different behaviors in response to environmental changes. Taking inspiration from neuroscience, we address this problem by utilizing artificial neural networks (NNs) as agent controllers, and mechanisms such as neuromodulation and synaptic gating. The novel aspect of this work is the introduction of a type of artificial neuron we call "switch neuron". A switch neuron regulates the flow of information in NNs by selectively gating all but one of its incoming synaptic connections, effectively allowing only one signal to propagate forward. The allowed connection is determined by the switch neuron's level of modulatory activation which is affected by modulatory signals, such as signals that encode some information about the reward received by the agent. An important aspect of the switch neuron is that it can be used in appropriate "switch modules" in order to modulate other switch neurons. As we show, the introduction of the switch modules enables the creation of sequences of gating events. This is achieved through the design of a modulatory pathway capable of exploring in a principled manner all permutations of the connections arriving on the switch neurons. We test the model by presenting appropriate architectures in nonstationary binary association problems and T-maze tasks. The results show that for all tasks, the switch neuron architectures generate optimal adaptive behaviors, providing evidence that the switch neuron model could be a valuable tool in simulations where behavioral plasticity is required. Copyright © 2015 Elsevier Ltd. All rights reserved.

Resistive switching in Pt/TiO{sub 2}/Pt

Energy Technology Data Exchange (ETDEWEB)

Jeong, Doo Seok

2008-08-15

Recently, the resistive switching behavior in TiO{sub 2} has drawn attention due to its application to resistive random access memory (RRAM) devices. TiO{sub 2} shows characteristic non-volatile resistive switching behavior, i.e. reversible switching between a high resistance state (HRS) and a low resistance state (LRS). Both unipolar resistive switching (URS) and bipolar resistive switching (BRS) are found to be observed in TiO{sub 2} depending on the compliance current for the electroforming. In this thesis the characteristic current-voltage (I-V) hysteresis in three different states of TiO{sub 2}, pristine, URS-activated, and BRS-activated states, was investigated and understood in terms of the migration of oxygen vacancies in TiO{sub 2}. The I-V hysteresis of pristine TiO{sub 2} was found to show volatile behavior. That is, the temporary variation of the resistance took place depending on the applied voltage. However, the I-V hysteresis of URS- and BRS-activated states showed non-volatile resistive switching behavior. Some evidences proving the evolution of oxygen gas during electroforming were obtained from time-of-flight secondary ion mass spectroscopy analysis and the variation of the morphology of switching cells induced by the electroforming. On the assumption that a large number of oxygen vacancies are introduced by the electroforming process, the I-V behavior in electroformed switching cells was simulated with varying the distribution of oxygen vacancies in electroformed TiO{sub x} (x

Float level switch for a nuclear power plant containment vessel

International Nuclear Information System (INIS)

Powell, J.G.

1993-01-01

This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel. 1 figures

Float level switch for a nuclear power plant containment vessel

Science.gov (United States)

Powell, James G.

1993-01-01

This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel.

High-energy azimuthally polarized laser beam generation from an actively Q-switched Nd:YAG laser with c-cut YVO4 crystal

Science.gov (United States)

Guo, Jing; Zhang, Baofu; Jiao, Zhongxing; He, Guangyuan; Wang, Biao

2018-05-01

A high-energy, azimuthally polarized (AP) and actively Q-switched Nd:YAG laser is demonstrated. The thermal bipolar lensing effect in the Nd:YAG laser rod is used as a polarization discriminator, and a c-cut YVO4 crystal is inserted into the laser cavity to increase the mode-selecting ability of the cavity for AP mode. The laser generated AP pulses with maximum pulse energy as high as 4.2 mJ. To the best of our knowledge, this is the highest pulse energy obtained from an actively Q-switched AP laser. The pulse energy remained higher than 1 mJ over a wide range of repetition rates from 5 kHz to 25 kHz.

DNA and RNA-controlled switching of protein kinase activity

NARCIS (Netherlands)

Röglin, L.; Altenbrunn, F.; Seitz, O.

2009-01-01

Protein switches use the binding energy gained upon recognition of ligands to modulate the conformation and binding properties of protein segments. We explored whether the programmable nucleic acid mediated recognition might be used to design or mimic constraints that limit the conformational

Operation of a homeostatic sleep switch.

Science.gov (United States)

Pimentel, Diogo; Donlea, Jeffrey M; Talbot, Clifford B; Song, Seoho M; Thurston, Alexander J F; Miesenböck, Gero

2016-08-18

Sleep disconnects animals from the external world, at considerable risks and costs that must be offset by a vital benefit. Insight into this mysterious benefit will come from understanding sleep homeostasis: to monitor sleep need, an internal bookkeeper must track physiological changes that are linked to the core function of sleep. In Drosophila, a crucial component of the machinery for sleep homeostasis is a cluster of neurons innervating the dorsal fan-shaped body (dFB) of the central complex. Artificial activation of these cells induces sleep, whereas reductions in excitability cause insomnia. dFB neurons in sleep-deprived flies tend to be electrically active, with high input resistances and long membrane time constants, while neurons in rested flies tend to be electrically silent. Correlative evidence thus supports the simple view that homeostatic sleep control works by switching sleep-promoting neurons between active and quiescent states. Here we demonstrate state switching by dFB neurons, identify dopamine as a neuromodulator that operates the switch, and delineate the switching mechanism. Arousing dopamine caused transient hyperpolarization of dFB neurons within tens of milliseconds and lasting excitability suppression within minutes. Both effects were transduced by Dop1R2 receptors and mediated by potassium conductances. The switch to electrical silence involved the downregulation of voltage-gated A-type currents carried by Shaker and Shab, and the upregulation of voltage-independent leak currents through a two-pore-domain potassium channel that we term Sandman. Sandman is encoded by the CG8713 gene and translocates to the plasma membrane in response to dopamine. dFB-restricted interference with the expression of Shaker or Sandman decreased or increased sleep, respectively, by slowing the repetitive discharge of dFB neurons in the ON state or blocking their entry into the OFF state. Biophysical changes in a small population of neurons are thus linked to the

Default mode network abnormalities during state switching in attention deficit hyperactivity disorder.

Science.gov (United States)

Sidlauskaite, J; Sonuga-Barke, E; Roeyers, H; Wiersema, J R

2016-02-01

Individuals with attention deficit hyperactivity disorder (ADHD) display excess levels of default mode network (DMN) activity during goal-directed tasks, which are associated with attentional disturbances and performance decrements. One hypothesis is that this is due to attenuated down-regulation of this network during rest-to-task switching. A second related hypothesis is that it may be associated with right anterior insula (rAI) dysfunction - a region thought to control the actual state-switching process. These hypotheses were tested in the current fMRI study in which 19 adults with ADHD and 21 typically developing controls undertook a novel state-to-state switching paradigm. Advance cues signalled upcoming switches between rest and task periods and switch-related anticipatory modulation of DMN and rAI was measured. To examine whether rest-to-task switching impairments may be a specific example of a more general state regulation deficit, activity upon task-to-rest cues was also analysed. Against our hypotheses, we found that the process of down-regulating the DMN when preparing to switch from rest to task was unimpaired in ADHD and that there was no switch-specific deficit in rAI modulation. However, individuals with ADHD showed difficulties up-regulating the DMN when switching from task to rest. Rest-to-task DMN attenuation seems to be intact in adults with ADHD and thus appears unrelated to excess DMN activity observed during tasks. Instead, individuals with ADHD exhibit attenuated up-regulation of the DMN, hence suggesting disturbed re-initiation of a rest state.

Switching of chirality by light

NARCIS (Netherlands)

Feringa, B.L.; Schoevaars, A.M; Jager, W.F.; de Lange, B.; Huck, N.P.M.

1996-01-01

Optically active photoresponsive molecules are described by which control of chirality is achieved by light. These chiroptical molecular switches are based on inherently dissymmetric overcrowded alkenes and the synthesis, resolution and dynamic stereochemical properties are discussed. Introduction

Ferroelectric switching of elastin

Science.gov (United States)

Liu, Yuanming; Cai, Hong-Ling; Zelisko, Matthew; Wang, Yunjie; Sun, Jinglan; Yan, Fei; Ma, Feiyue; Wang, Peiqi; Chen, Qian Nataly; Zheng, Hairong; Meng, Xiangjian; Sharma, Pradeep; Zhang, Yanhang; Li, Jiangyu

2014-01-01

Ferroelectricity has long been speculated to have important biological functions, although its very existence in biology has never been firmly established. Here, we present compelling evidence that elastin, the key ECM protein found in connective tissues, is ferroelectric, and we elucidate the molecular mechanism of its switching. Nanoscale piezoresponse force microscopy and macroscopic pyroelectric measurements both show that elastin retains ferroelectricity at 473 K, with polarization on the order of 1 μC/cm2, whereas coarse-grained molecular dynamics simulations predict similar polarization with a Curie temperature of 580 K, which is higher than most synthetic molecular ferroelectrics. The polarization of elastin is found to be intrinsic in tropoelastin at the monomer level, analogous to the unit cell level polarization in classical perovskite ferroelectrics, and it switches via thermally activated cooperative rotation of dipoles. Our study sheds light onto a long-standing question on ferroelectric switching in biology and establishes ferroelectricity as an important biophysical property of proteins. This is a critical first step toward resolving its physiological significance and pathological implications. PMID:24958890

Non-switching to switching transferring mechanism investigation for Ag/SiO x /p-Si structure with SiO x deposited by HWCVD

Science.gov (United States)

Liu, Yanhong; Wang, Ruoying; Li, Zhongyue; Wang, Song; Huang, Yang; Peng, Wei

2018-04-01

We proposed and fabricated an Ag/SiO x /p-Si sandwich structure, in which amorphous SiO x films were deposited through hot wire chemical vapor deposition (HWCVD) using tetraethylorthosilicate (TEOS) as Si and O precursor. Experimental results indicate that the I–V properties of this structure transfer from non-switching to switching operation as the SiO x deposition temperature increased. The device with SiO x deposited at high deposition temperature exhibits typical bipolar switching properties, which can be potentially used in resistive switching random accessible memory (RRAM). The transferring mechanism from non-switching to switching can be ascribed to the change of structural and electronic properties of SiO x active layer deposited at different temperatures, as evidenced by analyzing FTIR spectrum and fitting its I–V characteristics curves. This work demonstrates a safe and practicable low-temperature device-grade SiO x film deposition technology by conducting HWCVD from TEOS.

Digital switched hydraulics

Science.gov (United States)

Pan, Min; Plummer, Andrew

2018-06-01

This paper reviews recent developments in digital switched hydraulics particularly the switched inertance hydraulic systems (SIHSs). The performance of SIHSs is presented in brief with a discussion of several possible configurations and control strategies. The soft switching technology and high-speed switching valve design techniques are discussed. Challenges and recommendations are given based on the current research achievements.

Distributed Consensus of Stochastic Delayed Multi-agent Systems Under Asynchronous Switching.

Science.gov (United States)

Wu, Xiaotai; Tang, Yang; Cao, Jinde; Zhang, Wenbing

2016-08-01

In this paper, the distributed exponential consensus of stochastic delayed multi-agent systems with nonlinear dynamics is investigated under asynchronous switching. The asynchronous switching considered here is to account for the time of identifying the active modes of multi-agent systems. After receipt of confirmation of mode's switching, the matched controller can be applied, which means that the switching time of the matched controller in each node usually lags behind that of system switching. In order to handle the coexistence of switched signals and stochastic disturbances, a comparison principle of stochastic switched delayed systems is first proved. By means of this extended comparison principle, several easy to verified conditions for the existence of an asynchronously switched distributed controller are derived such that stochastic delayed multi-agent systems with asynchronous switching and nonlinear dynamics can achieve global exponential consensus. Two examples are given to illustrate the effectiveness of the proposed method.

Enhancement of resistive switching properties in Al2O3 bilayer-based atomic switches: multilevel resistive switching

Science.gov (United States)

Vishwanath, Sujaya Kumar; Woo, Hyunsuk; Jeon, Sanghun

2018-06-01

Atomic switches are considered to be building blocks for future non-volatile data storage and internet of things. However, obtaining device structures capable of ultrahigh density data storage, high endurance, and long data retention, and more importantly, understanding the switching mechanisms are still a challenge for atomic switches. Here, we achieved improved resistive switching performance in a bilayer structure containing aluminum oxide, with an oxygen-deficient oxide as the top switching layer and stoichiometric oxide as the bottom switching layer, using atomic layer deposition. This bilayer device showed a high on/off ratio (105) with better endurance (∼2000 cycles) and longer data retention (104 s) than single-oxide layers. In addition, depending on the compliance current, the bilayer device could be operated in four different resistance states. Furthermore, the depth profiles of the hourglass-shaped conductive filament of the bilayer device was observed by conductive atomic force microscopy.

From design of activity-based costing systems to their regular use From design of activity-based costing systems to their regular use Del diseño de modelos de costes basados en las actividades a su uso normalizado

Directory of Open Access Journals (Sweden)

M. Angels Fito

2011-11-01

Full Text Available Purpose: To understand why many companies that develop activity-based costing (ABC systems do not use them on a regular basis.Design/methodology/approach: We review the existing literature on the process of ABC implementation, concentrating specifically on the step from the acceptance of an ABC model to its routine use. We identify key factors for successful uptake of ABC systems as a regular management tool and use these factors to interpret the experience of two companies that illustrate, respectively, a success and a failure.Findings: Sixteen factors are identified that positively or negatively influence the actual use of ABC costing systems. These factors can be grouped into six categories: strategic, individual, organizational, technological, operational and external factors.Originality/value: This paper sheds some light on the paradoxical situation that regular usage of ABC systems is not as common as might be expected given their widespread acceptance on a conceptual level.Purpose: To understand why many companies that develop activity-based costing (ABC systems do not use them on a regular basis.Design/methodology/approach: We review the existing literature on the process of ABC implementation, concentrating specifically on the step from the acceptance of an ABC model to its routine use. We identify key factors for successful uptake of ABC systems as a regular management tool and use these factors to interpret the experience of two companies that illustrate, respectively, a success and a failure.Findings: Sixteen factors are identified that positively or negatively influence the actual use of ABC costing systems. These factors can be grouped into six categories: strategic, individual, organizational, technological, operational and external factors.Originality/value: This paper sheds some light on the paradoxical situation that regular usage of ABC systems is not as common as might be expected given their widespread acceptance on a

Electrostatically actuated resonant switches for earthquake detection

KAUST Repository

Ramini, Abdallah H.

2013-04-01

The modeling and design of electrostatically actuated resonant switches (EARS) for earthquake and seismic applications are presented. The basic concepts are based on operating an electrically actuated resonator close to instability bands of frequency, where it is forced to collapse (pull-in) if operated within these bands. By careful tuning, the resonator can be made to enter the instability zone upon the detection of the earthquake signal, thereby pulling-in as a switch. Such a switching action can be functionalized for useful functionalities, such as shutting off gas pipelines in the case of earthquakes, or can be used to activate a network of sensors for seismic activity recording in health monitoring applications. By placing a resonator on a printed circuit board (PCB) of a natural frequency close to that of the earthquake\\'s frequency, we show significant improvement on the detection limit of the EARS lowering it considerably to less than 60% of the EARS by itself without the PCB. © 2013 IEEE.

Regularity and irreversibility of weekly travel behavior

NARCIS (Netherlands)

Kitamura, R.; van der Hoorn, A.I.J.M.

1987-01-01

Dynamic characteristics of travel behavior are analyzed in this paper using weekly travel diaries from two waves of panel surveys conducted six months apart. An analysis of activity engagement indicates the presence of significant regularity in weekly activity participation between the two waves.

Compact, Energy-Efficient High-Frequency Switched Capacitor Neural Stimulator With Active Charge Balancing.

Science.gov (United States)

Hsu, Wen-Yang; Schmid, Alexandre

2017-08-01

Safety and energy efficiency are two major concerns for implantable neural stimulators. This paper presents a novel high-frequency, switched capacitor (HFSC) stimulation and active charge balancing scheme, which achieves high energy efficiency and well-controlled stimulation charge in the presence of large electrode impedance variations. Furthermore, the HFSC can be implemented in a compact size without any external component to simultaneously enable multichannel stimulation by deploying multiple stimulators. The theoretical analysis shows significant benefits over the constant-current and voltage-mode stimulation methods. The proposed solution was fabricated using a 0.18 μm high-voltage technology, and occupies only 0.035 mm 2 for a single stimulator. The measurement result shows 50% peak energy efficiency and confirms the effectiveness of active charge balancing to prevent the electrode dissolution.

Comparison of hemodynamic and nutritional parameters between older persons practicing regular physical activity, nonsmokers and ex-smokers

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Rebelatto Marcelo N

2010-11-01

Full Text Available Abstract Background Sedentary lifestyle combined with smoking, contributes to the development of a set of chronic diseases and to accelerating the course of aging. The aim of the study was to compare the hemodynamic and nutritional parameters between elderly persons practicing regular physical activity, nonsmokers and ex-smokers. Methods The sample was comprised of 40 elderly people practicing regular physical activity for 12 months, divided into a Nonsmoker Group and an Ex-smoker Group. During a year four trimestrial evaluations were performed, in which the hemodynamic (blood pressure, heart rate- HR and VO2 and nutritional status (measured by body mass index data were collected. The paired t-test and t-test for independent samples were applied in the intragroup and intergroup analysis, respectively. Results The mean age of the groups was 68.35 years, with the majority of individuals in the Nonsmoker Group being women (n = 15 and the Ex-smoker Group composed of men (n = 11. In both groups the variables studied were within the limits of normality for the age. HR was diminished in the Nonsmoker Group in comparison with the Ex-smoker Group (p = 0.045 between the first and last evaluation. In the intragroup analysis it was verified that after one year of exercise, there was significant reduction in the HR in the Nonsmoker Group (p = 0.002 and a significant increase in VO2 for the Ex-smoker Group (p = 0.010. There are no significant differences between the hemodynamic and nutritional conditions in both groups. Conclusion In elderly persons practicing regular physical activity, it was observed that the studied variables were maintained over the course of a year, and there was no association with the history of smoking, except for HR and VO2.

Congenital blindness limits allocentric to egocentric switching ability.

Science.gov (United States)

Ruggiero, Gennaro; Ruotolo, Francesco; Iachini, Tina

2018-03-01

Many everyday spatial activities require the cooperation or switching between egocentric (subject-to-object) and allocentric (object-to-object) spatial representations. The literature on blind people has reported that the lack of vision (congenital blindness) may limit the capacity to represent allocentric spatial information. However, research has mainly focused on the selective involvement of egocentric or allocentric representations, not the switching between them. Here we investigated the effect of visual deprivation on the ability to switch between spatial frames of reference. To this aim, congenitally blind (long-term visual deprivation), blindfolded sighted (temporary visual deprivation) and sighted (full visual availability) participants were compared on the Ego-Allo switching task. This task assessed the capacity to verbally judge the relative distances between memorized stimuli in switching (from egocentric-to-allocentric: Ego-Allo; from allocentric-to-egocentric: Allo-Ego) and non-switching (only-egocentric: Ego-Ego; only-allocentric: Allo-Allo) conditions. Results showed a difficulty in congenitally blind participants when switching from allocentric to egocentric representations, not when the first anchor point was egocentric. In line with previous results, a deficit in processing allocentric representations in non-switching conditions also emerged. These findings suggest that the allocentric deficit in congenital blindness may determine a difficulty in simultaneously maintaining and combining different spatial representations. This deficit alters the capacity to switch between reference frames specifically when the first anchor point is external and not body-centered.

Voluntary switching between identities in dissociative identity disorder: A functional MRI case study.

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Savoy, R L; Frederick, B B; Keuroghlian, A S; Wolk, P C

2012-01-01

Patients who suffer from dissociative identity disorder present unique scientific and clinical challenges for psychology and psychiatry. We have been fortunate in working with a patient who-while undergoing functional MRI-can switch rapidly and voluntarily between her main personality (a middle-aged, high-functioning woman) and an alternate personality (a 4-6-year-old girl). A unique task was designed to isolate the processes occurring during the switches between these personalities. Data are from two imaging sessions, conducted months apart, each showing the same activated areas during switches between these personalities. The activated areas include the following: the primary sensory and motor cortex, likely associated with characteristic facial movements made during switching; the nucleus accumbens bilaterally, possibly associated with aspects of reward connected with switching; and prefrontal sites, presumably associated with the executive control involved in the switching of personalities.

Diode pumped actively Q-switched Nd:YVO4 self-Raman laser

International Nuclear Information System (INIS)

Su Fufang; Zhang Xingyu; Wang Qingpu; Ding Shuanghong; Jia Peng; Li Shutao; Fan Shuzhen; Zhang Chen; Liu Bo

2006-01-01

By using Nd:YVO 4 as the gain medium and the Raman medium simultaneously, the actively Q-switched operation of the self-Raman Nd:YVO 4 laser at 1176 nm was realized. The output characteristics including the average power, pulse energy and pulse width versus the incident pump power and pulse repetition rate were investigated. At a pulse repetition rate of 20 kHz an average power up to 0.57 W was obtained with the incident pump power of 10.2 W, corresponding to a conversion efficiency of 5.6% with respect to the diode laser input power. Meanwhile, an analysis of the self-Raman Nd:YVO 4 laser was carried out by using the rate equations. The obtained theoretical results were in agreement with the experimental results on the whole

A nanoplasmonic switch based on molecular machines

KAUST Repository

Zheng, Yue Bing

2009-06-01

We aim to develop a molecular-machine-driven nanoplasmonic switch for its use in future nanophotonic integrated circuits (ICs) that have applications in optical communication, information processing, biological and chemical sensing. Experimental data show that an Au nanodisk array, coated with rotaxane molecular machines, switches its localized surface plasmon resonances (LSPR) reversibly when it is exposed to chemical oxidants and reductants. Conversely, bare Au nanodisks and disks coated with mechanically inert control compounds, do not display the same switching behavior. Along with calculations based on time-dependent density functional theory (TDDFT), these observations suggest that the nanoscale movements within surface-bound "molecular machines" can be used as the active components in plasmonic devices. ©2009 IEEE.

Demonstration of Ultra-Fast Switching in Nano metallic Resistive Switching Memory Devices

International Nuclear Information System (INIS)

Yang, Y.

2016-01-01

Interdependency of switching voltage and time creates a dilemma/obstacle for most resistive switching memories, which indicates low switching voltage and ultra-fast switching time cannot be simultaneously achieved. In this paper, an ultra-fast (sub-100 ns) yet low switching voltage resistive switching memory device (“nano metallic ReRAM”) was demonstrated. Experimental switching voltage is found independent of pulse width (intrinsic device property) when the pulse is long but shows abrupt time dependence (“cliff”) as pulse width approaches characteristic RC time of memory device (extrinsic device property). Both experiment and simulation show that the onset of cliff behavior is dependent on physical device size and parasitic resistance, which is expected to diminish as technology nodes shrink down. We believe this study provides solid evidence that nano metallic resistive switching memory can be reliably operated at low voltage and ultra-fast regime, thus beneficial to future memory technology.

Immunoglobulin class-switch recombination deficiencies.

Science.gov (United States)

Durandy, Anne; Kracker, Sven

2012-07-30

Immunoglobulin class-switch recombination deficiencies (Ig-CSR-Ds) are rare primary immunodeficiencies characterized by defective switched isotype (IgG/IgA/IgE) production. Depending on the molecular defect in question, the Ig-CSR-D may be combined with an impairment in somatic hypermutation (SHM). Some of the mechanisms underlying Ig-CSR and SHM have been described by studying natural mutants in humans. This approach has revealed that T cell-B cell interaction (resulting in CD40-mediated signaling), intrinsic B-cell mechanisms (activation-induced cytidine deaminase-induced DNA damage), and complex DNA repair machineries (including uracil-N-glycosylase and mismatch repair pathways) are all involved in class-switch recombination and SHM. However, several of the mechanisms required for full antibody maturation have yet to be defined. Elucidation of the molecular defects underlying the diverse set of Ig-CSR-Ds is essential for understanding Ig diversification and has prompted better definition of the clinical spectrum of diseases and the development of increasingly accurate diagnostic and therapeutic approaches.

Validating an infrared thermal switch as a novel access technology

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Memarian Negar

2010-08-01

Full Text Available Abstract Background Recently, a novel single-switch access technology based on infrared thermography was proposed. The technology exploits the temperature differences between the inside and surrounding areas of the mouth as a switch trigger, thereby allowing voluntary switch activation upon mouth opening. However, for this technology to be clinically viable, it must be validated against a gold standard switch, such as a chin switch, that taps into the same voluntary motion. Methods In this study, we report an experiment designed to gauge the concurrent validity of the infrared thermal switch. Ten able-bodied adults participated in a series of 3 test sessions where they simultaneously used both an infrared thermal and conventional chin switch to perform multiple trials of a number identification task with visual, auditory and audiovisual stimuli. Participants also provided qualitative feedback about switch use. User performance with the two switches was quantified using an efficiency measure based on mutual information. Results User performance (p = 0.16 and response time (p = 0.25 with the infrared thermal switch were comparable to those of the gold standard. Users reported preference for the infrared thermal switch given its non-contact nature and robustness to changes in user posture. Conclusions Thermal infrared access technology appears to be a valid single switch alternative for individuals with disabilities who retain voluntary mouth opening and closing.

The effectiveness of regular leisure-time physical activities on long-term glycemic control in people with type 2 diabetes: A systematic review and meta-analysis.

Science.gov (United States)

Pai, Lee-Wen; Li, Tsai-Chung; Hwu, Yueh-Juen; Chang, Shu-Chuan; Chen, Li-Li; Chang, Pi-Ying

2016-03-01

The objective of this study was to systematically review the effectiveness of different types of regular leisure-time physical activities and pooled the effect sizes of those activities on long-term glycemic control in people with type 2 diabetes compared with routine care. This review included randomized controlled trials from 1960 to May 2014. A total of 10 Chinese and English databases were searched, following selection and critical appraisal, 18 randomized controlled trials with 915 participants were included. The standardized mean difference was reported as the summary statistic for the overall effect size in a random effects model. The results indicated yoga was the most effective in lowering glycated haemoglobin A1c (HbA1c) levels. Meta-analysis also revealed that the decrease in HbA1c levels of the subjects who took part in regular leisure-time physical activities was 0.60% more than that of control group participants. A higher frequency of regular leisure-time physical activities was found to be more effective in reducing HbA1c levels. The results of this review provide evidence of the benefits associated with regular leisure-time physical activities compared with routine care for lowering HbA1c levels in people with type 2 diabetes. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Multistage switching hardware and software implementations for student experiment purpose

Science.gov (United States)

Sani, A.; Suherman

2018-02-01

Current communication and internet networks are underpinned by the switching technologies that interconnect one network to the others. Students’ understanding on networks rely on how they conver the theories. However, understanding theories without touching the reality may exert spots in the overall knowledge. This paper reports the progress of the multistage switching design and implementation for student laboratory activities. The hardware and software designs are based on three stages clos switching architecture with modular 2x2 switches, controlled by an arduino microcontroller. The designed modules can also be extended for batcher and bayan switch, and working on circuit and packet switching systems. The circuit analysis and simulation show that the blocking probability for each switch combinations can be obtained by generating random or patterned traffics. The mathematic model and simulation analysis shows 16.4% blocking probability differences as the traffic generation is uniform. The circuits design components and interfacing solution have been identified to allow next step implementation.

Theory of circuit block switch-off

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S. Henzler

2004-01-01

Full Text Available Switching-off unused circuit blocks is a promising approach to supress static leakage currents in ultra deep sub-micron CMOS digital systems. Basic performance parameters of Circuit Block Switch-Off (CBSO schemes are defined and their dependence on basic circuit parameters is estimated. Therefore the design trade-off between strong leakage suppression in idle mode and adequate dynamic performance in active mode can be supported by simple analytic investigations. Additionally, a guideline for the estimation of the minimum time for which a block deactivation is useful is derived.

High Voltage, Fast-Switching Module for Active Control of Magnetic Fields and Edge Plasma Currents

Science.gov (United States)

Ziemba, Timothy; Miller, Kenneth; Prager, James; Slobodov, Ilia

2016-10-01

Fast, reliable, real-time control of plasma is critical to the success of magnetic fusion science. High voltage and current supplies are needed to mitigate instabilities in all experiments as well as disruption events in large scale tokamaks for steady-state operation. Silicon carbide (SiC) MOSFETs offer many advantages over IGBTs including lower drive energy requirements, lower conduction and switching losses, and higher switching frequency capabilities; however, these devices are limited to 1.2-1.7 kV devices. As fusion enters the long-pulse and burning plasma eras, efficiency of power switching will be important. Eagle Harbor Technologies (EHT), Inc. developing a high voltage SiC MOSFET module that operates at 10 kV. This switch module utilizes EHT gate drive technology, which has demonstrated the ability to increase SiC MOSFET switching efficiency. The module will allow more rapid development of high voltage switching power supplies at lower cost necessary for the next generation of fast plasma feedback and control. EHT is partnering with the High Beta Tokamak group at Columbia to develop detailed high voltage module specifications, to ensure that the final product meets the needs of the fusion science community.

Neural Mechanisms Underlying the Cost of Task Switching: An ERP Study

Science.gov (United States)

Li, Ling; Wang, Meng; Zhao, Qian-Jing; Fogelson, Noa

2012-01-01

Background When switching from one task to a new one, reaction times are prolonged. This phenomenon is called switch cost (SC). Researchers have recently used several kinds of task-switching paradigms to uncover neural mechanisms underlying the SC. Task-set reconfiguration and passive dissipation of a previously relevant task-set have been reported to contribute to the cost of task switching. Methodology/Principal Findings An unpredictable cued task-switching paradigm was used, during which subjects were instructed to switch between a color and an orientation discrimination task. Electroencephalography (EEG) and behavioral measures were recorded in 14 subjects. Response-stimulus interval (RSI) and cue-stimulus interval (CSI) were manipulated with short and long intervals, respectively. Switch trials delayed reaction times (RTs) and increased error rates compared with repeat trials. The SC of RTs was smaller in the long CSI condition. For cue-locked waveforms, switch trials generated a larger parietal positive event-related potential (ERP), and a larger slow parietal positivity compared with repeat trials in the short and long CSI condition. Neural SC of cue-related ERP positivity was smaller in the long RSI condition. For stimulus-locked waveforms, a larger switch-related central negative ERP component was observed, and the neural SC of the ERP negativity was smaller in the long CSI. Results of standardized low resolution electromagnetic tomography (sLORETA) for both ERP positivity and negativity showed that switch trials evoked larger activation than repeat trials in dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC). Conclusions/Significance The results provide evidence that both RSI and CSI modulate the neural activities in the process of task-switching, but that these have a differential role during task-set reconfiguration and passive dissipation of a previously relevant task-set. PMID:22860090

Neural mechanisms underlying the cost of task switching: an ERP study.

Directory of Open Access Journals (Sweden)

Ling Li

Full Text Available BACKGROUND: When switching from one task to a new one, reaction times are prolonged. This phenomenon is called switch cost (SC. Researchers have recently used several kinds of task-switching paradigms to uncover neural mechanisms underlying the SC. Task-set reconfiguration and passive dissipation of a previously relevant task-set have been reported to contribute to the cost of task switching. METHODOLOGY/PRINCIPAL FINDINGS: An unpredictable cued task-switching paradigm was used, during which subjects were instructed to switch between a color and an orientation discrimination task. Electroencephalography (EEG and behavioral measures were recorded in 14 subjects. Response-stimulus interval (RSI and cue-stimulus interval (CSI were manipulated with short and long intervals, respectively. Switch trials delayed reaction times (RTs and increased error rates compared with repeat trials. The SC of RTs was smaller in the long CSI condition. For cue-locked waveforms, switch trials generated a larger parietal positive event-related potential (ERP, and a larger slow parietal positivity compared with repeat trials in the short and long CSI condition. Neural SC of cue-related ERP positivity was smaller in the long RSI condition. For stimulus-locked waveforms, a larger switch-related central negative ERP component was observed, and the neural SC of the ERP negativity was smaller in the long CSI. Results of standardized low resolution electromagnetic tomography (sLORETA for both ERP positivity and negativity showed that switch trials evoked larger activation than repeat trials in dorsolateral prefrontal cortex (DLPFC and posterior parietal cortex (PPC. CONCLUSIONS/SIGNIFICANCE: The results provide evidence that both RSI and CSI modulate the neural activities in the process of task-switching, but that these have a differential role during task-set reconfiguration and passive dissipation of a previously relevant task-set.

Incorrect predictions reduce switch costs.

Science.gov (United States)

Kleinsorge, Thomas; Scheil, Juliane

2015-07-01

In three experiments, we combined two sources of conflict within a modified task-switching procedure. The first source of conflict was the one inherent in any task switching situation, namely the conflict between a task set activated by the recent performance of another task and the task set needed to perform the actually relevant task. The second source of conflict was induced by requiring participants to guess aspects of the upcoming task (Exps. 1 & 2: task identity; Exp. 3: position of task precue). In case of an incorrect guess, a conflict accrues between the representation of the guessed task and the actually relevant task. In Experiments 1 and 2, incorrect guesses led to an overall increase of reaction times and error rates, but they reduced task switch costs compared to conditions in which participants predicted the correct task. In Experiment 3, incorrect guesses resulted in faster performance overall and to a selective decrease of reaction times in task switch trials when the cue-target interval was long. We interpret these findings in terms of an enhanced level of controlled processing induced by a combination of two sources of conflict converging upon the same target of cognitive control. Copyright © 2015 Elsevier B.V. All rights reserved.

DREAM Controls the On/Off Switch of Specific Activity-Dependent Transcription Pathways

Science.gov (United States)

Mellström, Britt; Sahún, Ignasi; Ruiz-Nuño, Ana; Murtra, Patricia; Gomez-Villafuertes, Rosa; Savignac, Magali; Oliveros, Juan C.; Gonzalez, Paz; Kastanauskaite, Asta; Knafo, Shira; Zhuo, Min; Higuera-Matas, Alejandro; Errington, Michael L.; Maldonado, Rafael; DeFelipe, Javier; Jefferys, John G. R.; Bliss, Tim V. P.; Dierssen, Mara

2014-01-01

Changes in nuclear Ca2+ homeostasis activate specific gene expression programs and are central to the acquisition and storage of information in the brain. DREAM (downstream regulatory element antagonist modulator), also known as calsenilin/KChIP-3 (K+ channel interacting protein 3), is a Ca2+-binding protein that binds DNA and represses transcription in a Ca2+-dependent manner. To study the function of DREAM in the brain, we used transgenic mice expressing a Ca2+-insensitive/CREB-independent dominant active mutant DREAM (daDREAM). Using genome-wide analysis, we show that DREAM regulates the expression of specific activity-dependent transcription factors in the hippocampus, including Npas4, Nr4a1, Mef2c, JunB, and c-Fos. Furthermore, DREAM regulates its own expression, establishing an autoinhibitory feedback loop to terminate activity-dependent transcription. Ablation of DREAM does not modify activity-dependent transcription because of gene compensation by the other KChIP family members. The expression of daDREAM in the forebrain resulted in a complex phenotype characterized by loss of recurrent inhibition and enhanced long-term potentiation (LTP) in the dentate gyrus and impaired learning and memory. Our results indicate that DREAM is a major master switch transcription factor that regulates the on/off status of specific activity-dependent gene expression programs that control synaptic plasticity, learning, and memory. PMID:24366545

Distance-regular graphs

NARCIS (Netherlands)

van Dam, Edwin R.; Koolen, Jack H.; Tanaka, Hajime

2016-01-01

This is a survey of distance-regular graphs. We present an introduction to distance-regular graphs for the reader who is unfamiliar with the subject, and then give an overview of some developments in the area of distance-regular graphs since the monograph 'BCN'[Brouwer, A.E., Cohen, A.M., Neumaier,

Effect of Smoking Abstinence and Reduction in Asthmatic Smokers Switching to Electronic Cigarettes: Evidence for Harm Reversal

Directory of Open Access Journals (Sweden)

Riccardo Polosa

2014-05-01

Full Text Available Electronic cigarettes (e-cigs are marketed as safer alternatives to tobacco cigarettes and have shown to reduce their consumption. Here we report for the first time the effects of e-cigs on subjective and objective asthma parameters as well as tolerability in asthmatic smokers who quit or reduced their tobacco consumption by switching to these products. We retrospectively reviewed changes in spirometry data, airway hyper-responsiveness (AHR, asthma exacerbations and subjective asthma control in smoking asthmatics who switched to regular e-cig use. Measurements were taken prior to switching (baseline and at two consecutive visits (Follow-up/1 at 6 (±1 and Follow-up/2 at 12 (±2 months. Eighteen smoking asthmatics (10 single users, eight dual users were identified. Overall there were significant improvements in spirometry data, asthma control and AHR. These positive outcomes were noted in single and dual users. Reduction in exacerbation rates was reported, but was not significant. No severe adverse events were noted. This small retrospective study indicates that regular use of e-cigs to substitute smoking is associated with objective and subjective improvements in asthma outcomes. Considering that e-cig use is reportedly less harmful than conventional smoking and can lead to reduced cigarette consumption with subsequent improvements in asthma outcomes, this study shows that e-cigs can be a valid option for asthmatic patients who cannot quit smoking by other methods.

DESAIN DAN IMPLEMENTSI SOFT SWITCHING BOOST KONVERTER DENGAN SIMPLE AUXILLARY RESONANT SWITCH (SARC

Directory of Open Access Journals (Sweden)

Dimas Bagus Saputra

2017-01-01

Full Text Available Boost konverter merupakan penaik tegangan DC ke tegangan DC yang mempunyai tegangan output yang lebih tinggi dibanding inputnya. Penggunaan boost konverter diera modern semakin meningkat dan dibuat dengan dimensi yang lebih kecil, berat yang lebih ringan dan efisiensi yang lebih tinggi dibanding dengan boost konverter generasi terdahulu. Tetapi rugi-rugi periodik saat on/off meningkat. Untuk meraih kriteria tersebut, teknik hard switching boost konverter berevolusi menjadi teknik soft switching dengan menambah rangkaian simple auxiliary resonant circuit (SARC. Karena penambahan rangkaian SARC tersebut konverter bekerja pada kondisi zero-voltage switching switch (ZVS dan zero current switch (ZCS, sehingga saklar semikonduktor tidak bekerja secara hard switching lagi. Pada penelitian ini akan di desain dan diimplementaskan soft switching boost konverter dengan SARC. Kelebihan dari soft switching boost konverter dengan SARC adalah mempunyai efisiensi yang lebih tinggi dibanding dengan boost konverter konventional. Dari hasil implementasi menunjukkan konverter yang diajukan telah meraih zero voltage switch (ZVS. Sehingga boost konverter zero voltage switch (ZVS bisa diaplikasikan pada sistem power suplay yang membutuhkan efisiensi energi yang tinggi terutama pada daya yang tinggi.

Regular expressions cookbook

CERN Document Server

Goyvaerts, Jan

2009-01-01

This cookbook provides more than 100 recipes to help you crunch data and manipulate text with regular expressions. Every programmer can find uses for regular expressions, but their power doesn't come worry-free. Even seasoned users often suffer from poor performance, false positives, false negatives, or perplexing bugs. Regular Expressions Cookbook offers step-by-step instructions for some of the most common tasks involving this tool, with recipes for C#, Java, JavaScript, Perl, PHP, Python, Ruby, and VB.NET. With this book, you will: Understand the basics of regular expressions through a

Functional brain and age-related changes associated with congruency in task switching

Science.gov (United States)

Eich, Teal S.; Parker, David; Liu, Dan; Oh, Hwamee; Razlighi, Qolamreza; Gazes, Yunglin; Habeck, Christian; Stern, Yaakov

2016-01-01

Alternating between completing two simple tasks, as opposed to completing only one task, has been shown to produce costs to performance and changes to neural patterns of activity, effects which are augmented in old age. Cognitive conflict may arise from factors other than switching tasks, however. Sensorimotor congruency (whether stimulus-response mappings are the same or different for the two tasks) has been shown to behaviorally moderate switch costs in older, but not younger adults. In the current study, we used fMRI to investigate the neurobiological mechanisms of response-conflict congruency effects within a task switching paradigm in older (N=75) and younger (N=62) adults. Behaviorally, incongruency moderated age-related differences in switch costs. Neurally, switch costs were associated with greater activation in the dorsal attention network for older relative to younger adults. We also found that older adults recruited an additional set of brain areas in the ventral attention network to a greater extent than did younger adults to resolve congruency-related response-conflict. These results suggest both a network and an age-based dissociation between congruency and switch costs in task switching. PMID:27520472

Postural Effects of Vestibular Manipulation Depend on the Physical Activity Status.

Directory of Open Access Journals (Sweden)

Julien Maitre

Full Text Available The purpose of this study was to compare the effects of galvanic vestibular stimulation (GVS on postural control for participants of different physical activity status (i.e. active and non-active. Two groups of participants were recruited: one group of participants who regularly practised sports activities (active group, n = 17, and one group of participants who did not practise physical and/or sports activities (non-active group, n = 17. They were compared in a reference condition (i.e bipedal stance with eyes open and four vestibular manipulation condition (i.e. GVS at 0.5 mA and 3 mA, in accordance with two designs lasting 20 seconds. The centre of foot pressure displacement velocities were compared between the two groups. The main results indicate that the regular practice of sports activities counteracts postural control disruption caused by GVS. The active group demonstrated better postural control than the non-active group when subjected to higher vestibular manipulation. The active group may have developed their ability to reduce the influence of inaccurate vestibular signals. The active participants could identify the relevant sensory input, thought a better central integration, which enables them to switch faster between sensory inputs.

Neuromorphic atomic switch networks.

Directory of Open Access Journals (Sweden)

Audrius V Avizienis

Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

Saturated Switching Systems

CERN Document Server

Benzaouia, Abdellah

2012-01-01

Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

LL-regular grammars

NARCIS (Netherlands)

Nijholt, Antinus

1980-01-01

Culik II and Cogen introduced the class of LR-regular grammars, an extension of the LR(k) grammars. In this paper we consider an analogous extension of the LL(k) grammars called the LL-regular grammars. The relation of this class of grammars to other classes of grammars will be shown. Any LL-regular

Industry Switching in Developing Countries

DEFF Research Database (Denmark)

Newman, Carol; Rand, John; Tarp, Finn

Firm turnover (i.e. firm entry and exit) is a well-recognized source of sectorlevel productivity growth across developing and developed countries. In contrast, the role and importance of firms switching activities from one sector to another is little understood. Firm switchers are likely...

Uncertainty estimation of non-ideal analog switches using programmable Josephson voltage standards for mutual inductance measurement in the joule balance

International Nuclear Information System (INIS)

Wang, Gang; Zhang, Zhonghua; Li, Zhengkun; Xu, Jinxin; You, Qiang

2016-01-01

Measurement of the mutual inductance is one of the key techniques in the joule balance to determine the Planck constant h, where a standard-square-wave compensation method was proposed to accurately measure the dc value of the mutual inductance. With this method, analog switches are used to compose an analog-switch signal generator to synthesize the excitation and compensation voltages. However, the accuracy of the compensation voltage is influenced by the non-ideal behaviors of analog-switches. In this paper, the effect from these non-ideal switches is analyzed in detail and evaluated with the equivalent circuits. A programmable Josephson voltage standard (PJVS) is used to generate a reference compensation voltage to measure the time integration of the voltage waveform generated by the analog-switch signal generator. Moreover, the effect is also evaluated experimentally by comparing the difference between the mutual inductance measured with the analog-switch signal generator and the value determined by the PJVS-analog-switch generator alternately in the same mutual inductance measurement system. The result shows that the impact of analog switches is 1.97  ×  10 −7 with an uncertainty of 1.83  ×  10 −7 (k  =  1) and confirms that the analog switch method can be used regularly instead of the PJVS in the mutual inductance measurement for the joule balance experiment. (paper)

A Superconducting Dual-Channel Photonic Switch.

Science.gov (United States)

Srivastava, Yogesh Kumar; Manjappa, Manukumara; Cong, Longqing; Krishnamoorthy, Harish N S; Savinov, Vassili; Pitchappa, Prakash; Singh, Ranjan

2018-06-05

The mechanism of Cooper pair formation and its underlying physics has long occupied the investigation into high temperature (high-T c ) cuprate superconductors. One of the ways to unravel this is to observe the ultrafast response present in the charge carrier dynamics of a photoexcited specimen. This results in an interesting approach to exploit the dissipation-less dynamic features of superconductors to be utilized for designing high-performance active subwavelength photonic devices with extremely low-loss operation. Here, dual-channel, ultrafast, all-optical switching and modulation between the resistive and the superconducting quantum mechanical phase is experimentally demonstrated. The ultrafast phase switching is demonstrated via modulation of sharp Fano resonance of a high-T c yttrium barium copper oxide (YBCO) superconducting metamaterial device. Upon photoexcitation by femtosecond light pulses, the ultrasensitive cuprate superconductor undergoes dual dissociation-relaxation dynamics, with restoration of superconductivity within a cycle, and thereby establishes the existence of dual switching windows within a timescale of 80 ps. Pathways are explored to engineer the secondary dissociation channel which provides unprecedented control over the switching speed. Most importantly, the results envision new ways to accomplish low-loss, ultrafast, and ultrasensitive dual-channel switching applications that are inaccessible through conventional metallic and dielectric based metamaterials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nonlinear-Based MEMS Sensors and Active Switches for Gas and Acceleration Applications

KAUST Repository

Younis, Mohammad I.

2016-11-25

In this talk, we demonstrate the realization of smart sensors and actuators through the exploitation of principles of nonlinear dynamics at the micro scale. Specifically, we demonstrate combining sensing and actuation into a single device through what is called smart switches triggered by the detection of a desirable physical quantity. The concept aims to reduce the complexity of systems that rely on controllers and complex algorithms to realize on-demand trigger actions. In the first part of the talk, we discuss the category of switches triggered by the detection of gas. Toward this, electrostatically microbeams resonators are fabricated, then coated with highly absorbent polymers (MOFs), and afterward are exposed to gases. Such devices can be useful for instant alarming of toxic gases. In the second part, we demonstrate switches triggered by shock and acceleration. The concept is demonstrated on a millimeter-scale capacitive sensor. The sensor is tested using acceleration generated from shakers. Such devices can be used for the deployment of airbags in automobiles.

Coherent Multimodal Sensory Information Allows Switching between Gravitoinertial Contexts.

Science.gov (United States)

Barbiero, Marie; Rousseau, Célia; Papaxanthis, Charalambos; White, Olivier

2017-01-01

Whether the central nervous system is capable to switch between contexts critically depends on experimental details. Motor control studies regularly adopt robotic devices to perturb the dynamics of a certain task. Other approaches investigate motor control by altering the gravitoinertial context itself as in parabolic flights and human centrifuges. In contrast to conventional robotic experiments, where only the hand is perturbed, these gravitoinertial or immersive settings coherently plunge participants into new environments. However, radically different they are, perfect adaptation of motor responses are commonly reported. In object manipulation tasks, this translates into a good matching of the grasping force or grip force to the destabilizing load force. One possible bias in these protocols is the predictability of the forthcoming dynamics. Here we test whether the successful switching and adaptation processes observed in immersive environments are a consequence of the fact that participants can predict the perturbation schedule. We used a short arm human centrifuge to decouple the effects of space and time on the dynamics of an object manipulation task by adding an unnatural explicit position-dependent force. We created different dynamical contexts by asking 20 participants to move the object at three different paces. These contextual sessions were interleaved such that we could simulate concurrent learning. We assessed adaptation by measuring how grip force was adjusted to this unnatural load force. We found that the motor system can switch between new unusual dynamical contexts, as reported by surprisingly well-adjusted grip forces, and that this capacity is not a mere consequence of the ability to predict the time course of the upcoming dynamics. We posit that a coherent flow of multimodal sensory information born in a homogeneous milieu allows switching between dynamical contexts.

Coherent Multimodal Sensory Information Allows Switching between Gravitoinertial Contexts

Directory of Open Access Journals (Sweden)

Marie Barbiero

2017-05-01

Full Text Available Whether the central nervous system is capable to switch between contexts critically depends on experimental details. Motor control studies regularly adopt robotic devices to perturb the dynamics of a certain task. Other approaches investigate motor control by altering the gravitoinertial context itself as in parabolic flights and human centrifuges. In contrast to conventional robotic experiments, where only the hand is perturbed, these gravitoinertial or immersive settings coherently plunge participants into new environments. However, radically different they are, perfect adaptation of motor responses are commonly reported. In object manipulation tasks, this translates into a good matching of the grasping force or grip force to the destabilizing load force. One possible bias in these protocols is the predictability of the forthcoming dynamics. Here we test whether the successful switching and adaptation processes observed in immersive environments are a consequence of the fact that participants can predict the perturbation schedule. We used a short arm human centrifuge to decouple the effects of space and time on the dynamics of an object manipulation task by adding an unnatural explicit position-dependent force. We created different dynamical contexts by asking 20 participants to move the object at three different paces. These contextual sessions were interleaved such that we could simulate concurrent learning. We assessed adaptation by measuring how grip force was adjusted to this unnatural load force. We found that the motor system can switch between new unusual dynamical contexts, as reported by surprisingly well-adjusted grip forces, and that this capacity is not a mere consequence of the ability to predict the time course of the upcoming dynamics. We posit that a coherent flow of multimodal sensory information born in a homogeneous milieu allows switching between dynamical contexts.

Electronic logic to enhance switch reliability in detecting openings and closures of redundant switches

Science.gov (United States)

Cooper, James A.

1986-01-01

A logic circuit is used to enhance redundant switch reliability. Two or more switches are monitored for logical high or low output. The output for the logic circuit produces a redundant and failsafe representation of the switch outputs. When both switch outputs are high, the output is high. Similarly, when both switch outputs are low, the logic circuit's output is low. When the output states of the two switches do not agree, the circuit resolves the conflict by memorizing the last output state which both switches were simultaneously in and produces the logical complement of this output state. Thus, the logic circuit of the present invention allows the redundant switches to be treated as if they were in parallel when the switches are open and as if they were in series when the switches are closed. A failsafe system having maximum reliability is thereby produced.

Switched capacitor DC-DC converter with switch conductance modulation and Pesudo-fixed frequency control

DEFF Research Database (Denmark)

Larsen, Dennis Øland; Vinter, Martin; Jørgensen, Ivan Harald Holger

A switched capacitor dc-dc converter with frequency-planned control is presented. By splitting the output stage switches in eight segments the output voltage can be regulated with a combination of switching frequency and switch conductance. This allows for switching at predetermined frequencies, 31...

Role of allosteric switch residue histidine 195 in maintaining active-site asymmetry in presynaptic filaments of bacteriophage T4 UvsX recombinase.

Science.gov (United States)

Farb, Joshua N; Morrical, Scott W

2009-01-16

Recombinases of the highly conserved RecA/Rad51 family play central roles in homologous recombination and DNA double-stranded break repair. RecA/Rad51 enzymes form presynaptic filaments on single-stranded DNA (ssDNA) that are allosterically activated to catalyze ATPase and DNA strand-exchange reactions. Information is conveyed between DNA- and ATP-binding sites, in part, by a highly conserved glutamine residue (Gln194 in Escherichia coli RecA) that acts as an allosteric switch. The T4 UvsX protein is a divergent RecA ortholog and contains histidine (His195) in place of glutamine at the allosteric switch position. UvsX and RecA catalyze similar strand-exchange reactions, but differ in other properties. UvsX produces both ADP and AMP as products of its ssDNA-dependent ATPase activity--a property that is unique among characterized recombinases. Details of the kinetics of ssDNA-dependent ATP hydrolysis reactions indicate that UvsX-ssDNA presynaptic filaments are asymmetric and contain two classes of ATPase active sites: one that generates ADP, and another that generates AMP. Active-site asymmetry is reduced by mutations at the His195 position, since UvsX-H195Q and UvsX-H195A mutants both exhibit stronger ssDNA-dependent ATPase activity, with lower cooperativity and markedly higher ADP/AMP product ratios, than wild-type UvsX. Reduced active-site asymmetry correlates strongly with reduced ssDNA-binding affinity and DNA strand-exchange activity in both H195Q and H195A mutants. These and other results support a model in which allosteric switch residue His195 controls the formation of an asymmetric conformation of UvsX-ssDNA filaments that is active in DNA strand exchange. The implications of our findings for UvsX recombination functions, and for RecA functions in general, are discussed.

Effective switching frequency multiplier inverter

Science.gov (United States)

Su, Gui-Jia [Oak Ridge, TN; Peng, Fang Z [Okemos, MI

2007-08-07

A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

Instability in time-delayed switched systems induced by fast and random switching

Science.gov (United States)

Guo, Yao; Lin, Wei; Chen, Yuming; Wu, Jianhong

2017-07-01

In this paper, we consider a switched system comprising finitely or infinitely many subsystems described by linear time-delayed differential equations and a rule that orchestrates the system switching randomly among these subsystems, where the switching times are also randomly chosen. We first construct a counterintuitive example where even though all the time-delayed subsystems are exponentially stable, the behaviors of the randomly switched system change from stable dynamics to unstable dynamics with a decrease of the dwell time. Then by using the theories of stochastic processes and delay differential equations, we present a general result on when this fast and random switching induced instability should occur and we extend this to the case of nonlinear time-delayed switched systems as well.

Enhanced protein and biochemical production using CRISPRi-based growth switches

DEFF Research Database (Denmark)

Li, Songyuan; Jendresen, Christian Bille; Grünberger, Alexander

2016-01-01

functionality of the growth switches. Decoupling of growth from production of biochemicals was demonstrated for mevalonate, a precursor for isoprenoid compounds. Mass yield of mevalonate was increased by 41%, and production was maintained for more than 45 h after activation of the pyrF-based growth switch...

Combined deficiency of MSH2 and Sμ region abolishes class switch recombination.

Science.gov (United States)

Leduc, Claire; Haddad, Dania; Laviolette-Malirat, Nathalie; Nguyen Huu, Ngoc-Sa; Khamlichi, Ahmed Amine

2010-10-01

Class switch recombination (CSR) is mediated by G-rich tandem repeated sequences termed switch regions. Transcription of switch regions generates single-stranded R loops that provide substrates for activation-induced cytidine deaminase. Mice deficient in MSH2 have a mild defect in CSR and analysis of their switch junctions has led to a model in which MSH2 is more critical for switch recombination events outside than within the tandem repeats. It is also known that deletion of the whole Sμ region severely impairs but does not abrogate CSR despite the lack of detectable R loops. Here, we demonstrate that deficiency of both MSH2 and the Sμ region completely abolishes CSR and that the abrogation occurs at the genomic level. This finding further supports the crucial role of MSH2 outside the tandem repeats. It also indicates that during CSR, MSH2 has access to activation-induced cytidine deaminase targets in R-loop-deficient Iμ-Cμ sequences rarely used in CSR, suggesting an MSH2-dependent DNA processing activity at the Iμ exon that may decrease with transcription elongation across the Sμ region.

The Impact of Computerization on Regular Employment (Japanese)

OpenAIRE

SUNADA Mitsuru; HIGUCHI Yoshio; ABE Masahiro

2004-01-01

This paper uses micro data from the Basic Survey of Japanese Business Structure and Activity to analyze the effects of companies' introduction of information and telecommunications technology on employment structures, especially regular versus non-regular employment. Firstly, examination of trends in the ratio of part-time workers recorded in the Basic Survey shows that part-time worker ratios in manufacturing firms are rising slightly, but that companies with a high proportion of part-timers...

Latching micro optical switch

Science.gov (United States)

Garcia, Ernest J; Polosky, Marc A

2013-05-21

An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

Brain activity dynamics in human parietal regions during spontaneous switches in bistable perception.

Science.gov (United States)

Megumi, Fukuda; Bahrami, Bahador; Kanai, Ryota; Rees, Geraint

2015-02-15

The neural mechanisms underlying conscious visual perception have been extensively investigated using bistable perception paradigms. Previous functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) studies suggest that the right anterior superior parietal (r-aSPL) and the right posterior superior parietal lobule (r-pSPL) have opposite roles in triggering perceptual reversals. It has been proposed that these two areas are part of a hierarchical network whose dynamics determine perceptual switches. However, how these two parietal regions interact with each other and with the rest of the brain during bistable perception is not known. Here, we investigated such a model by recording brain activity using fMRI while participants viewed a bistable structure-from-motion stimulus. Using dynamic causal modeling (DCM), we found that resolving such perceptual ambiguity was specifically associated with reciprocal interactions between these parietal regions and V5/MT. Strikingly, the strength of bottom-up coupling between V5/MT to r-pSPL and from r-pSPL to r-aSPL predicted individual mean dominance duration. Our findings are consistent with a hierarchical predictive coding model of parietal involvement in bistable perception and suggest that visual information processing underlying spontaneous perceptual switches can be described as changes in connectivity strength between parietal and visual cortical regions. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Avalanche photoconductive switching

Science.gov (United States)

Pocha, M. D.; Druce, R. L.; Wilson, M. J.; Hofer, W. W.

This paper describes work being done at Lawrence Livermore National Laboratory on the avalanche mode of operation of laser triggered photoconductive switches. We have been able to generate pulses with amplitudes of 2 kV to 35 kV and rise times of 300 to 500 ps, and with a switching gain (energy of output electrical pulse vs energy of trigger optical pulse) of 10(exp 3) to over 10(exp 5). Switches with two very different physical configurations and with two different illumination wavelengths (1.06 micrometer, 890 nm) exhibit very similar behavior. The avalanche switching behavior, therefore, appears to be related to the material parameters rather than the optical wavelength or switch geometry. Considerable further work needs to be done to fully characterize and understand this mode of operation.

Avalanche photoconductive switching

Energy Technology Data Exchange (ETDEWEB)

Pocha, M.D.; Druce, R.L.; Wilson, M.J.; Hofer, W.W.

1989-01-01

This paper describes work being done at Lawrence Livermore National Laboratory on the avalanche mode of operation of laser triggered photoconductive switches. We have been able to generate pulses with amplitudes of 2 kV--35 kV and rise times of 300--500 ps, and with a switching gain (energy of output electrical pulse vs energy of trigger optical pulse) of 10{sup 3} to over 10{sup 5}. Switches with two very different physical configurations and with two different illumination wavelengths (1.06 {mu}m, 890 nm) exhibit very similar behavior. The avalanche switching behavior, therefore, appears to be related to the material parameters rather than the optical wavelength or switch geometry. Considerable further work needs to be done to fully characterize and understand this mode of operation. 3 refs., 6 figs.

Surface effects of electrode-dependent switching behavior of resistive random-access memory

KAUST Repository

Ke, Jr Jian; Wei, Tzu Chiao; Tsai, Dung Sheng; Lin, Chun-Ho; He, Jr-Hau

2016-01-01

of the oxygen chemisorption process was proposed to explain this electrode-dependent switching behavior. The temperature-dependent switching voltage demonstrates that the ReRAM devices fabricated with Pt electrodes have a lower activation energy

An iterative method for Tikhonov regularization with a general linear regularization operator

NARCIS (Netherlands)

Hochstenbach, M.E.; Reichel, L.

2010-01-01

Tikhonov regularization is one of the most popular approaches to solve discrete ill-posed problems with error-contaminated data. A regularization operator and a suitable value of a regularization parameter have to be chosen. This paper describes an iterative method, based on Golub-Kahan

160-Gb/s Silicon All-Optical Packet Switch for Buffer-less Optical Burst Switching

DEFF Research Database (Denmark)

Hu, Hao; Ji, Hua; Pu, Minhao

2015-01-01

We experimentally demonstrate a 160-Gb/s Ethernet packet switch using an 8.6-mm-long silicon nanowire for optical burst switching, based on cross phase modulation in silicon. One of the four packets at the bit rate of 160 Gb/s is switched by an optical control signal using a silicon based 1 × 1 all......-optical packet switch. Error free performance (BER silicon packet switch based optical burst switching, which might be desirable for high-speed interconnects within a short...

Resistive Switching of Ta2O5-Based Self-Rectifying Vertical-Type Resistive Switching Memory

Science.gov (United States)

Ryu, Sungyeon; Kim, Seong Keun; Choi, Byung Joon

2018-01-01

To efficiently increase the capacity of resistive switching random-access memory (RRAM) while maintaining the same area, a vertical structure similar to a vertical NAND flash structure is needed. In addition, the sneak-path current through the half-selected neighboring memory cell should be mitigated by integrating a selector device with each RRAM cell. In this study, an integrated vertical-type RRAM cell and selector device was fabricated and characterized. Ta2O5 as the switching layer and TaOxNy as the selector layer were used to preliminarily study the feasibility of such an integrated device. To make the side contact of the bottom electrode with active layers, a thick Al2O3 insulating layer was placed between the Pt bottom electrode and the Ta2O5/TaOxNy stacks. Resistive switching phenomena were observed under relatively low currents (below 10 μA) in this vertical-type RRAM device. The TaOxNy layer acted as a nonlinear resistor with moderate nonlinearity. Its low-resistance-state and high-resistance-state were well retained up to 1000 s.

Experimental results of thermally controlled superconducting switches for high frequency operation

International Nuclear Information System (INIS)

Mulder, G.B.J.; IerAvest, D.; Tenkate, H.H.J.; Krooshoop, H.J.G.; Van de Klundert, L.

1988-01-01

The aim of this study is to develop thermally controlled switches which are to be used in superconducting rectifiers operating at a few hertz and 1 kA. Usually, the operating frequency of thermally controlled rectifiers is limited to about 0.1 Hz due to the thermal recovery times of the switches. The thermal switches have to satisfy two conditions which are specific for the application in a superconducting rectifier: a) they have to operate in the repetitive mode so beside short activation times, fast recovery times of the switches are equally important, b) the power required to effect and maintain the normal state of the switches should be low since it will determine the rectifier efficiency. To what extent these obviously conflicting demands can be satisfied depends on the material and geometry of the switch. This paper presents a theoretical model of the thermal behaviour of a switch. The calculations are compared with experimental results of several switches having recovery times between 40 and 200 ms. Also, the feasibility of such switches for application in superconducting rectifiers operating at a few hertz with an acceptable efficiency is demonstrated

Task Uncertainty Can Account for Mixing and Switch Costs in Task-Switching

Science.gov (United States)

Rennie, Jaime L.

2015-01-01

Cognitive control is required in situations that involve uncertainty or change, such as when resolving conflict, selecting responses and switching tasks. Recently, it has been suggested that cognitive control can be conceptualised as a mechanism which prioritises goal-relevant information to deal with uncertainty. This hypothesis has been supported using a paradigm that requires conflict resolution. In this study, we examine whether cognitive control during task switching is also consistent with this notion. We used information theory to quantify the level of uncertainty in different trial types during a cued task-switching paradigm. We test the hypothesis that differences in uncertainty between task repeat and task switch trials can account for typical behavioural effects in task-switching. Increasing uncertainty was associated with less efficient performance (i.e., slower and less accurate), particularly on switch trials and trials that afford little opportunity for advance preparation. Interestingly, both mixing and switch costs were associated with a common episodic control process. These results support the notion that cognitive control may be conceptualised as an information processor that serves to resolve uncertainty in the environment. PMID:26107646

Controllability of multi-agent systems with periodically switching topologies and switching leaders

Science.gov (United States)

Tian, Lingling; Zhao, Bin; Wang, Long

2018-05-01

This paper considers controllability of multi-agent systems with periodically switching topologies and switching leaders. The concept of m-periodic controllability is proposed, and a criterion for m-periodic controllability is established. The effect of the duration of subsystems on controllability is analysed by utilising a property of analytic functions. In addition, the influence of switching periods on controllability is investigated, and an algorithm is proposed to search for the fewest periods to ensure controllability. A necessary condition for m-periodic controllability is obtained from the perspective of eigenvectors of the subsystems' Laplacian matrices. For a system with switching leaders, it is proved that switching-leader controllability is equivalent to multiple-leader controllability. Furthermore, both the switching order and the tenure of agents being leaders have no effect on the controllability. Some examples are provided to illustrate the theoretical results.

Regular Expression Pocket Reference

CERN Document Server

Stubblebine, Tony

2007-01-01

This handy little book offers programmers a complete overview of the syntax and semantics of regular expressions that are at the heart of every text-processing application. Ideal as a quick reference, Regular Expression Pocket Reference covers the regular expression APIs for Perl 5.8, Ruby (including some upcoming 1.9 features), Java, PHP, .NET and C#, Python, vi, JavaScript, and the PCRE regular expression libraries. This concise and easy-to-use reference puts a very powerful tool for manipulating text and data right at your fingertips. Composed of a mixture of symbols and text, regular exp

Surface effects of electrode-dependent switching behavior of resistive random-access memory

KAUST Repository

Ke, Jr Jian

2016-09-26

The surface effects of ZnO-based resistive random-access memory (ReRAM) were investigated using various electrodes. Pt electrodes were found to have better performance in terms of the device\\'s switching functionality. A thermodynamic model of the oxygen chemisorption process was proposed to explain this electrode-dependent switching behavior. The temperature-dependent switching voltage demonstrates that the ReRAM devices fabricated with Pt electrodes have a lower activation energy for the chemisorption process, resulting in a better resistive switching performance. These findings provide an in-depth understanding of electrode-dependent switching behaviors and can serve as design guidelines for future ReRAM devices.

Domain switching in single-phase multiferroics

Science.gov (United States)

Jia, Tingting; Cheng, Zhenxiang; Zhao, Hongyang; Kimura, Hideo

2018-06-01

Multiferroics are a time-honoured research subject by reason for their tremendous application potential in the information industry, such as in multi-state information storage devices and new types of sensors. An outburst of studies on multiferroicity has been witnessed in the 21st century, although this field has a long research history since the 19th century. Multiferroicity has now become one of the hottest research topics in condensed matter physics and materials science. Numerous efforts have been made to investigate the cross-coupling phenomena among ferroic orders such as ferroelectricity, (anti-)ferromagnetism, and ferroelasticity, especially the coupling between electric and magnetic orderings that would account for the magnetoelectric (ME) effect in multiferroic materials. The magnetoelectric properties and coupling behavior of single phase multiferroics are dominated by their domain structures. It was also noted that, however, the multiferroic materials exhibit very complicated domain structures. Studies on domain structure characterization and domain switching are a crucial step in the exploration of approaches to the control and manipulation of magnetic (electric) properties using an electric (magnetic) field or other means. In this review, following a concise outline of our current basic knowledge on the magnetoelectric (ME) effect, we summarize some important research activities on domain switching in single-phase multiferroic materials in the form of single crystals and thin films, especially domain switching behavior involving strain and the related physics in the last decade. We also introduce recent developments in characterization techniques for domain structures of ferroelectric or multiferroic materials, which have significantly advanced our understanding of domain switching dynamics and interactions. The effects of a series of issues such as electric field, magnetic field, and stress effects on domain switching are been discussed as well. It

Industry switching in developing countries

DEFF Research Database (Denmark)

Newman, Carol; Rand, John; Tarp, Finn

2013-01-01

Firm turnover (i.e., firm entry and exit) is a well-recognized source of sector-level productivity growth. In contrast, the role and importance of firms that switch activities from one sector to another is not well understood. Firm switchers are likely to be unique, differing from both newly esta...

Optical Activation of Germanium Plasmonic Antennas in the Mid-Infrared

Science.gov (United States)

Fischer, Marco P.; Schmidt, Christian; Sakat, Emilie; Stock, Johannes; Samarelli, Antonio; Frigerio, Jacopo; Ortolani, Michele; Paul, Douglas J.; Isella, Giovanni; Leitenstorfer, Alfred; Biagioni, Paolo; Brida, Daniele

2016-07-01

Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate. This direct approach activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-infrared spectral range. The optical switching lasts for hundreds of picoseconds until charge recombination redshifts the plasma frequency. The full behavior of the structures is modeled by the electrodynamic response established by an electron-hole plasma in a regular array of antennas.

Electronic bipolar resistive switching behavior in Ni/VOx/Al device

Energy Technology Data Exchange (ETDEWEB)

Xia, Mengseng [School of Electronic Information Engineering, Hebei University of Technology, Tianjin Key Laboratory of Electronic Materials and Devices, Tianjin 300130 (China); School of Electronic Information Engineering, Tianjin Key Laboratory of Film Electronic & Communication Devices, Tianjin University of Technology, Tianjin 300384 (China); Zhang, Kailiang, E-mail: kailiang_zhang@163.com [School of Electronic Information Engineering, Tianjin Key Laboratory of Film Electronic & Communication Devices, Tianjin University of Technology, Tianjin 300384 (China); Yang, Ruixia, E-mail: yangrx@hebut.edu.cn [School of Electronic Information Engineering, Hebei University of Technology, Tianjin Key Laboratory of Electronic Materials and Devices, Tianjin 300130 (China); Wang, Fang; Zhang, Zhichao; Wu, Shijian [School of Electronic Information Engineering, Tianjin Key Laboratory of Film Electronic & Communication Devices, Tianjin University of Technology, Tianjin 300384 (China)

2017-07-15

Highlights: • The resistive random access memory of Ni/VOx/Al was fabricated. • The device has the electronic bipolar resistive switching characteristic. • The activity energy (Ea) of HRS has been calculated. • The reasons of the degradation of the resistance ratio of HRS/LRS were analyzed. - Abstract: In this paper, the Ni/VOx/Al resistive random access memory (RRAM) device is constructed and it shows bipolar resistive switching behavior, low resistive state (LRS) nonlinearity, and good retention. The set and reset processes are likely induced by the electron trapping and detrapping of trapping centers in the VOx films, respectively. The conduction mechanism in negative/positive region are controlled by space charge limited current mechanism (SCLC)/Schottky emission. The temperature dependence of I–V curves for HRS is measured to confirm the defects trapping and detrapping electrons model. activation energy was calculated to analyze the endurance performance of the device. The detailed analysis of the switching behavior with SCLC mechanism and Schottky emission mechanism could provide useful information for electronic bipolar resistive switching (eBRS) characteristics.

Electronic bipolar resistive switching behavior in Ni/VOx/Al device

International Nuclear Information System (INIS)

Xia, Mengseng; Zhang, Kailiang; Yang, Ruixia; Wang, Fang; Zhang, Zhichao; Wu, Shijian

2017-01-01

Highlights: • The resistive random access memory of Ni/VOx/Al was fabricated. • The device has the electronic bipolar resistive switching characteristic. • The activity energy (Ea) of HRS has been calculated. • The reasons of the degradation of the resistance ratio of HRS/LRS were analyzed. - Abstract: In this paper, the Ni/VOx/Al resistive random access memory (RRAM) device is constructed and it shows bipolar resistive switching behavior, low resistive state (LRS) nonlinearity, and good retention. The set and reset processes are likely induced by the electron trapping and detrapping of trapping centers in the VOx films, respectively. The conduction mechanism in negative/positive region are controlled by space charge limited current mechanism (SCLC)/Schottky emission. The temperature dependence of I–V curves for HRS is measured to confirm the defects trapping and detrapping electrons model. activation energy was calculated to analyze the endurance performance of the device. The detailed analysis of the switching behavior with SCLC mechanism and Schottky emission mechanism could provide useful information for electronic bipolar resistive switching (eBRS) characteristics.

Low Voltage Current Mode Switched-Current-Mirror Mixer

Directory of Open Access Journals (Sweden)

Chunhua Wang

2009-09-01

Full Text Available A new CMOS active mixer topology can operate at 1 V supply voltage by use of SCM (switched currentmirror. Such current-mode mixer requires less voltage headroom with good linearization. Mixing is achieved with four improved current mirrors, which are alternatively activated. For ideal switching, the operation is equivalent to a conventional active mixer. This paper analyzes the performance of the SCM mixer, in comparison with the conventional mixer, demonstrating competitive performance at a lower supply voltage. Moreover, the new mixer’s die, without any passive components, is very small, and the conversion gain is easy to adjust. An experimental prototype was designed and simulated in standard chartered 0.18μm RF CMOS Process with Spectre in Cadence Design Systems. Experimental results show satisfactory mixer performance at 2.4 GHz.

Optimal switching using coherent control

DEFF Research Database (Denmark)

Kristensen, Philip Trøst; Heuck, Mikkel; Mørk, Jesper

2013-01-01

that the switching time, in general, is not limited by the cavity lifetime. Therefore, the total energy required for switching is a more relevant figure of merit than the switching speed, and for a particular two-pulse switching scheme we use calculus of variations to optimize the switching in terms of input energy....

Resistive switching memories in MoS{sub 2} nanosphere assemblies

Energy Technology Data Exchange (ETDEWEB)

Xu, Xiao-Yong, E-mail: xxxy@yzu.edu.cn, E-mail: xcxseu@seu.edu.cn, E-mail: jghu@yzu.edu.cn [School of Physics Science and Technology, Yangzhou University, Yangzhou 225002 (China); State Key Laboratory of Bioelectronics and School of Electronic Science and Engineering, Southeast University, Nanjing 210096 (China); School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); Yin, Zong-You [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); Xu, Chun-Xiang, E-mail: xxxy@yzu.edu.cn, E-mail: xcxseu@seu.edu.cn, E-mail: jghu@yzu.edu.cn; Dai, Jun [State Key Laboratory of Bioelectronics and School of Electronic Science and Engineering, Southeast University, Nanjing 210096 (China); Hu, Jing-Guo, E-mail: xxxy@yzu.edu.cn, E-mail: xcxseu@seu.edu.cn, E-mail: jghu@yzu.edu.cn [School of Physics Science and Technology, Yangzhou University, Yangzhou 225002 (China)

2014-01-20

A resistive switching memory device consisting of reduced graphene oxide and indium tin oxide as top/bottom two electrodes, separated by dielectric MoS{sub 2} nanosphere assemblies as the active interlayer, was fabricated. This device exhibits the rewritable nonvolatile resistive switching with low SET/RESET voltage (∼2 V), high ON/OFF resistance ratio (∼10{sup 4}), and superior electrical bistability, introducing a potential application in data storage field. The resistance switching mechanism was analyzed in the assumptive model of the electron tunneling across the polarized potential barriers.

Tunnel Effect in CNNs: Image Reconstruction From Max-Switch Locations

DEFF Research Database (Denmark)

de La Roche Saint Andre, Matthieu; Rieger, Laura; Hannemose, Morten

2016-01-01

In this paper, we show that reconstruction of an image passed through a neural network is possible, using only the locations of the max pool activations. This was demonstrated with an architecture consisting of an encoder and a decoder. The decoder is a mirrored version of the encoder, where...... convolutions are replaced with deconvolutions and poolings are replaced with unpooling layers. The locations of the max pool switches are transmitted to the corresponding unpooling layer. The reconstruction is computed only from these switches without the use of feature values. Using only the max switch...

Switch-connected HyperX network

Science.gov (United States)

Chen, Dong; Heidelberger, Philip

2018-02-13

A network system includes a plurality of sub-network planes and global switches. The sub-network planes have a same network topology as each other. Each of the sub-network planes includes edge switches. Each of the edge switches has N ports. Each of the global switches is configured to connect a group of edge switches at a same location in the sub-network planes. In each of the sub-network planes, some of the N ports of each of the edge switches are connected to end nodes, and others of the N ports are connected to other edge switches in the same sub-network plane, other of the N ports are connected to at least one of the global switches.

Total variation regularization for fMRI-based prediction of behavior

Science.gov (United States)

Michel, Vincent; Gramfort, Alexandre; Varoquaux, Gaël; Eger, Evelyn; Thirion, Bertrand

2011-01-01

While medical imaging typically provides massive amounts of data, the extraction of relevant information for predictive diagnosis remains a difficult challenge. Functional MRI (fMRI) data, that provide an indirect measure of task-related or spontaneous neuronal activity, are classically analyzed in a mass-univariate procedure yielding statistical parametric maps. This analysis framework disregards some important principles of brain organization: population coding, distributed and overlapping representations. Multivariate pattern analysis, i.e., the prediction of behavioural variables from brain activation patterns better captures this structure. To cope with the high dimensionality of the data, the learning method has to be regularized. However, the spatial structure of the image is not taken into account in standard regularization methods, so that the extracted features are often hard to interpret. More informative and interpretable results can be obtained with the ℓ1 norm of the image gradient, a.k.a. its Total Variation (TV), as regularization. We apply for the first time this method to fMRI data, and show that TV regularization is well suited to the purpose of brain mapping while being a powerful tool for brain decoding. Moreover, this article presents the first use of TV regularization for classification. PMID:21317080

Subnanosecond linear GaAs photoconductive switching, revision 1

Science.gov (United States)

Druce, R. L.; Pocha, M. D.; Griffin, K. L.; Hofer, W. W.

Research was conducted in photoconductive switching for the purpose of generating subnanosecond pulses in the 25 to 50kV range. The very fast recombination rates of Gallium Arsenide (GaAs) was exploited to explore the potential of GaAs as a closing and opening switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). The closing time of a linear GaAs switch is theoretically limited by the characteristics of the laser pulse used to activate the switch (the carrier generation time in GaAs is (approx. 10(-14) sec) while the opening time is theoretically limited by the recombination time of the carriers. The recombination time is several ns for commercially available semi-insulating GaAs. Doping or neutron irradiation can reduce the recombination time to less than 100 ps. Switch closing times of less than 200 ps with a 100 ps duration laser pulse and opening times of less than 400 ps with neutron irradiated GaAs at fields of tens of kV/cm was observed. The illumination source was a Nd:YAG laser operating at 1.06 microns.

Changes in puffing behavior among smokers who switched from tobacco to electronic cigarettes.

Science.gov (United States)

Lee, Yong Hee; Gawron, Michal; Goniewicz, Maciej Lukasz

2015-09-01

Nicotine intake from electronic cigarette (e-cigarettes) increases with user's experience. This suggests that smokers who switched from tobacco to electronic cigarettes compensate for nicotine over time to get as much nicotine as they need. One of the mechanisms by which smokers may compensate for nicotine is by modifying their puffing behavior. The aim of the study was to assess the changes in puffing behavior after switching from conventional to electronic cigarettes among regular smokers. Twenty smokers (11 female, aged 31±10, CPD 16±8, FTND 4±3, and exhaled CO 16±17 (mean±SD)) who were naïve to e-cigarettes participated in this study. They were asked to substitute their regular tobacco cigarettes with first generation e-cigarettes (labeled 18mg nicotine) for two weeks. Puffing topography (number of puffs, puff volume, intervals between puffs, and average puff flow rate) was measured at the initial use (baseline), as well as after one and two weeks of product use. We tested changes in puffing topography outcomes using repeated measures ANOVA. We found that after one week of using e-cigarettes, participants significantly increased the average time they puffed on e-cigarettes from 2.2±0.1 (mean±SEM) to 3.1±0.3s (pe-cigarette use (preason for changing puffing behavior is to compensate for less efficient nicotine delivery from e-cigarettes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Task-set switching under cue-based versus memory-based switching conditions in younger and older adults.

Science.gov (United States)

Kray, Jutta

2006-08-11

Adult age differences in task switching and advance preparation were examined by comparing cue-based and memory-based switching conditions. Task switching was assessed by determining two types of costs that occur at the general (mixing costs) and specific (switching costs) level of switching. Advance preparation was investigated by varying the time interval until the next task (short, middle, very long). Results indicated that the implementation of task sets was different for cue-based switching with random task sequences and memory-based switching with predictable task sequences. Switching costs were strongly reduced under cue-based switching conditions, indicating that task-set cues facilitate the retrieval of the next task. Age differences were found for mixing costs and for switching costs only under cue-based conditions in which older adults showed smaller switching costs than younger adults. It is suggested that older adults adopt a less extreme bias between two tasks than younger adults in situations associated with uncertainty. For cue-based switching with random task sequences, older adults are less engaged in a complete reconfiguration of task sets because of the probability of a further task change. Furthermore, the reduction of switching costs was more pronounced for cue- than memory-based switching for short preparation intervals, whereas the reduction of switch costs was more pronounced for memory- than cue-based switching for longer preparation intervals at least for older adults. Together these findings suggest that the implementation of task sets is functionally different for the two types of task-switching conditions.

Task uncertainty can account for mixing and switch costs in task-switching.

Directory of Open Access Journals (Sweden)

Patrick S Cooper

Full Text Available Cognitive control is required in situations that involve uncertainty or change, such as when resolving conflict, selecting responses and switching tasks. Recently, it has been suggested that cognitive control can be conceptualised as a mechanism which prioritises goal-relevant information to deal with uncertainty. This hypothesis has been supported using a paradigm that requires conflict resolution. In this study, we examine whether cognitive control during task switching is also consistent with this notion. We used information theory to quantify the level of uncertainty in different trial types during a cued task-switching paradigm. We test the hypothesis that differences in uncertainty between task repeat and task switch trials can account for typical behavioural effects in task-switching. Increasing uncertainty was associated with less efficient performance (i.e., slower and less accurate, particularly on switch trials and trials that afford little opportunity for advance preparation. Interestingly, both mixing and switch costs were associated with a common episodic control process. These results support the notion that cognitive control may be conceptualised as an information processor that serves to resolve uncertainty in the environment.

LCT protective dump-switch tests

International Nuclear Information System (INIS)

Parsons, W.M.

1981-01-01

Each of the six coils in the Large Coil Task (LCT) has a separate power supply, dump resistor, and switching circuit. Each switching circuit contains five switches, two of which are redundant. The three remaining switches perform separate duties in an emergency dump situation. These three switches were tested to determine their ability to meet the LCT conditions

Structural analysis and biological activity of a highly regular glycosaminoglycan from Achatina fulica.

Science.gov (United States)

Liu, Jie; Zhou, Lutan; He, Zhicheng; Gao, Na; Shang, Feineng; Xu, Jianping; Li, Zi; Yang, Zengming; Wu, Mingyi; Zhao, Jinhua

2018-02-01

Edible snails have been widely used as a health food and medicine in many countries. A unique glycosaminoglycan (AF-GAG) was purified from Achatina fulica. Its structure was analyzed and characterized by chemical and instrumental methods, such as Fourier transform infrared spectroscopy, analysis of monosaccharide composition, and 1D/2D nuclear magnetic resonance spectroscopy. Chemical composition analysis indicated that AF-GAG is composed of iduronic acid (IdoA) and N-acetyl-glucosamine (GlcNAc) and its average molecular weight is 118kDa. Structural analysis clarified that the uronic acid unit in glycosaminoglycan (GAG) is the fully epimerized and the sequence of AF-GAG is →4)-α-GlcNAc (1→4)-α-IdoA2S (1→. Although its structure with a uniform repeating disaccharide is similar to those of heparin and heparan sulfate, this GAG is structurally highly regular and homogeneous. Anticoagulant activity assays indicated that AF-GAG exhibits no anticoagulant activities, but considering its structural characteristic, other bioactivities such as heparanase inhibition may be worthy of further study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fuselage panel noise attenuation by piezoelectric switching control

International Nuclear Information System (INIS)

Makihara, Kanjuro; Onoda, Junjiro; Minesugi, Kenji; Miyakawa, Takeya

2010-01-01

This paper describes a problem that we encountered in our noise attenuation project and our solution for it. We intend to attenuate low-frequency noise that transmits through aircraft fuselage panels. Our method of noise attenuation is implemented with a piezoelectric semi-active system having a selective switch instead of an active energy-supply system. The semi-active controller is based on the predicted sound pressure distribution obtained from acoustic emission analysis. Experiments and numerical simulations demonstrate that the semi-active method attenuates acoustic levels of not only the simple monochromatic noise but also of broadband noise. We reveal that tuning the electrical parameters in the circuit is the key to effective noise attenuation, to overcome the acoustic excitation problem due to sharp switching actions, as well as to control chattering problems. The results obtained from this investigation provide meaningful insights into designing noise attenuation systems for comfortable aircraft cabin environments

Optically controlled redshift switching effects in hybrid fishscale metamaterials

Science.gov (United States)

Wang, Yu; Zhu, Jinwei; Zhang, Hao; Zhang, Wenxing; Dong, Guohua; Ye, Peng; Lv, Tingting; Zhu, Zheng; Li, Yuxiang; Guan, Chunying; Shi, Jinhui

2018-05-01

We numerically demonstrate optically controlled THz response in a hybrid fishscale metamaterial with embedded photoconductive silicon at oblique incidence of TE wave. The oblique incidence allows excitation of Fano-type trapped mode resonance in a 2-fold rotational symmetric metamaterial. The hybrid fishscale metamaterial exhibits an optically controlled redshift switching effect in the THz range. The switching effect is dominated by the conductivity of the silicon instead of mechanically adjusting angles of incidence. The tuning frequency range is up to 0.3THz with a large modulation depth and high transmission in the "ON" state. The fishscale metamaterial-based switching has been experimentally verified by its microwave counterpart integrated by variable resistors. Our work provides an alternative route to realize tunable Fano-type response in metamaterials and is of importance to active manipulation, sensing and switching of THz waves in practical applications.

Differential brain activation patterns in adult attention-deficit hyperactivity disorder (ADHD) associated with task switching

NARCIS (Netherlands)

Dibbets, P.; Evers, E.A.; Hurks, P.P.; Bakker, K.; Jolles, J.

2010-01-01

Objective: The main aim of the study was to examine blood oxygen level-dependent response during task switching in adults with attention-deficit/hyperactivity disorder (ADHD). Method: Fifteen male adults with ADHD and 14 controls participated and performed a task-switching paradigm. Results:

Catalytic micromotor generating self-propelled regular motion through random fluctuation

Science.gov (United States)

Yamamoto, Daigo; Mukai, Atsushi; Okita, Naoaki; Yoshikawa, Kenichi; Shioi, Akihisa

2013-07-01

Most of the current studies on nano/microscale motors to generate regular motion have adapted the strategy to fabricate a composite with different materials. In this paper, we report that a simple object solely made of platinum generates regular motion driven by a catalytic chemical reaction with hydrogen peroxide. Depending on the morphological symmetry of the catalytic particles, a rich variety of random and regular motions are observed. The experimental trend is well reproduced by a simple theoretical model by taking into account of the anisotropic viscous effect on the self-propelled active Brownian fluctuation.

Switch on, switch off: stiction in nanoelectromechanical switches

KAUST Repository

Wagner, Till J W

2013-06-13

We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the \\'ON\\' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between \\'free\\', \\'pinned\\' and \\'clamped\\' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. © 2013 IOP Publishing Ltd.

P-glycoprotein ATPase activity requires lipids to activate a switch at the first transmission interface.

Science.gov (United States)

Loo, Tip W; Clarke, David M

2016-04-01

P-glycoprotein (P-gp) is an ABC (ATP-Binding Cassette) drug pump. A common feature of ABC proteins is that they are organized into two wings. Each wing contains a transmembrane domain (TMD) and a nucleotide-binding domain (NBD). Drug substrates and ATP bind at the interface between the TMDs and NBDs, respectively. Drug transport involves ATP-dependent conformational changes between inward- (open, NBDs far apart) and outward-facing (closed, NBDs close together) conformations. P-gps crystallized in the presence of detergent show an open structure. Human P-gp is inactive in detergent but basal ATPase activity is restored upon addition of lipids. The lipids might cause closure of the wings to bring the NBDs close together to allow ATP hydrolysis. We show however, that cross-linking the wings together did not activate ATPase activity when lipids were absent suggesting that lipids may induce other structural changes required for ATPase activity. We then tested the effect of lipids on disulfide cross-linking of mutants at the first transmission interface between intracellular loop 4 (TMD2) and NBD1. Mutants L443C/S909C and L443C/R905C but not G471C/S909C and V472C/S909C were cross-linked with oxidant when in membranes. The mutants were then purified and cross-linked with or without lipids. Mutants G471C/S909C and V472C/S909C cross-linked only in the absence of lipids whereas mutants L443C/S909C and L443C/R905C were cross-linked only in the presence of lipids. The results suggest that lipids activate a switch at the first transmission interface and that the structure of P-gp is different in detergents and lipids. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Biodistribution of the radiopharmaceutical sodium pertechnetate after biliopancreatic bypass with a duodenal switch

International Nuclear Information System (INIS)

Araujo-Filho, Irami; Rego, Amalia Cinthia Meneses; Brandao-Neto, Jose; Villarim-Neto, Arthur; Egito, Eryvaldo Socrates Tabosa; Azevedo, Italo Medeiros; Medeiros, Aldo Cunha

2007-01-01

Study with the purpose to examine the effects of duodenal switch (DS), regularly performed in morbidly obese patients, on biodistribution of sodium pertechnetate in several organs of rats. There was no early or late mortality in either rats groups. The values of percent radioactivity per gram of tissue (%ATI/g), showed no significant difference in liver, stomach, small bowel, duodenum, kidney, heart, bladder, bone and brain, when compared the DS rats with sham and controls rats. A postoperative significant increase (p<0.05) in mean %ATI/g levels was observed in spleen, pancreas and muscle in group DS rats, as compared to group S and C rats. In the lung there was an increase and in thyroid a decrease in mean %ATI/g of DS rats, when compared to sham rats (p<0.05). In conclusion, the biliopancreatic diversion with duodenal switch in rats modified the biodistribution of sodium pertechnetate in thyroid, lung, pancreas, spleen and muscle. (author)

Biodistribution of the radiopharmaceutical sodium pertechnetate after biliopancreatic bypass with a duodenal switch

Energy Technology Data Exchange (ETDEWEB)

Araujo-Filho, Irami; Rego, Amalia Cinthia Meneses; Brandao-Neto, Jose; Villarim-Neto, Arthur; Egito, Eryvaldo Socrates Tabosa; Azevedo, Italo Medeiros; Medeiros, Aldo Cunha [Universidade Federal do Rio Grande do Norte, Natal, RN (Brazil). Programa de Pos-graduacao em Ciencias da Saude]. E-mail: aldo@ufrnet.br

2007-09-15

Study with the purpose to examine the effects of duodenal switch (DS), regularly performed in morbidly obese patients, on biodistribution of sodium pertechnetate in several organs of rats. There was no early or late mortality in either rats groups. The values of percent radioactivity per gram of tissue (%ATI/g), showed no significant difference in liver, stomach, small bowel, duodenum, kidney, heart, bladder, bone and brain, when compared the DS rats with sham and controls rats. A postoperative significant increase (p<0.05) in mean %ATI/g levels was observed in spleen, pancreas and muscle in group DS rats, as compared to group S and C rats. In the lung there was an increase and in thyroid a decrease in mean %ATI/g of DS rats, when compared to sham rats (p<0.05). In conclusion, the biliopancreatic diversion with duodenal switch in rats modified the biodistribution of sodium pertechnetate in thyroid, lung, pancreas, spleen and muscle. (author)

Control synthesis of switched systems

CERN Document Server

Zhao, Xudong; Niu, Ben; Wu, Tingting

2017-01-01

This book offers its readers a detailed overview of the synthesis of switched systems, with a focus on switching stabilization and intelligent control. The problems investigated are not only previously unsolved theoretically but also of practical importance in many applications: voltage conversion, naval piloting and navigation and robotics, for example. The book considers general switched-system models and provides more efficient design methods to bring together theory and application more closely than was possible using classical methods. It also discusses several different classes of switched systems. For general switched linear systems and switched nonlinear systems comprising unstable subsystems, it introduces novel ideas such as invariant subspace theory and the time-scheduled Lyapunov function method of designing switching signals to stabilize the underlying systems. For some typical switched nonlinear systems affected by various complex dynamics, the book proposes novel design approaches based on inte...

The geometry of continuum regularization

International Nuclear Information System (INIS)

Halpern, M.B.

1987-03-01

This lecture is primarily an introduction to coordinate-invariant regularization, a recent advance in the continuum regularization program. In this context, the program is seen as fundamentally geometric, with all regularization contained in regularized DeWitt superstructures on field deformations

Regular expression containment

DEFF Research Database (Denmark)

Henglein, Fritz; Nielsen, Lasse

2011-01-01

We present a new sound and complete axiomatization of regular expression containment. It consists of the conventional axiomatiza- tion of concatenation, alternation, empty set and (the singleton set containing) the empty string as an idempotent semiring, the fixed- point rule E* = 1 + E × E......* for Kleene-star, and a general coin- duction rule as the only additional rule. Our axiomatization gives rise to a natural computational inter- pretation of regular expressions as simple types that represent parse trees, and of containment proofs as coercions. This gives the axiom- atization a Curry......-Howard-style constructive interpretation: Con- tainment proofs do not only certify a language-theoretic contain- ment, but, under our computational interpretation, constructively transform a membership proof of a string in one regular expres- sion into a membership proof of the same string in another regular expression. We...

Supersymmetric dimensional regularization

International Nuclear Information System (INIS)

Siegel, W.; Townsend, P.K.; van Nieuwenhuizen, P.

1980-01-01

There is a simple modification of dimension regularization which preserves supersymmetry: dimensional reduction to real D < 4, followed by analytic continuation to complex D. In terms of component fields, this means fixing the ranges of all indices on the fields (and therefore the numbers of Fermi and Bose components). For superfields, it means continuing in the dimensionality of x-space while fixing the dimensionality of theta-space. This regularization procedure allows the simple manipulation of spinor derivatives in supergraph calculations. The resulting rules are: (1) First do all algebra exactly as in D = 4; (2) Then do the momentum integrals as in ordinary dimensional regularization. This regularization procedure needs extra rules before one can say that it is consistent. Such extra rules needed for superconformal anomalies are discussed. Problems associated with renormalizability and higher order loops are also discussed

A Novel Single Switch Transformerless Quadratic DC/DC Buck-Boost Converter

DEFF Research Database (Denmark)

Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen

2017-01-01

A novel quadratic buck-boost DC/DC converter is presented in this study. The proposed converter utilizes only one active switch and can step-up/down the input voltage, while the existing single switch quadratic buck/boost converters can only work in step-up or step-down mode. First, the proposed ...

Low-Crosstalk Composite Optical Crosspoint Switches

Science.gov (United States)

Pan, Jing-Jong; Liang, Frank

1993-01-01

Composite optical switch includes two elementary optical switches in tandem, plus optical absorbers. Like elementary optical switches, composite optical switches assembled into switch matrix. Performance enhanced by increasing number of elementary switches. Advantage of concept: crosstalk reduced to acceptably low level at moderate cost of doubling number of elementary switches rather than at greater cost of tightening manufacturing tolerances and exerting more-precise control over operating conditions.

A soft switching with reduced voltage stress ZVT-PWM full-bridge converter

Science.gov (United States)

Sahin, Yakup; Ting, Naim Suleyman; Acar, Fatih

2018-04-01

This paper introduces a novel active snubber cell for soft switching pulse width modulation DC-DC converters. In the proposed converter, the main switch is turned on under zero voltage transition and turned off under zero voltage switching (ZVS). The auxiliary switch is turned on under zero current switching (ZCS) and turned off under zero current transition. The main diode is turned on under ZVS and turned off under ZCS. All of the other semiconductors in the converter are turned on and off with soft switching. There is no extra voltage stress on the semiconductor devices. Besides, the proposed converter has simple structure and ease of control due to common ground. The detailed theoretical analysis of the proposed converter is presented and also verified with both simulation and experimental study at 100 kHz switching frequency and 600 W output power. Furthermore, the efficiency of the proposed converter is 95.7% at nominal power.

Semisupervised Support Vector Machines With Tangent Space Intrinsic Manifold Regularization.

Science.gov (United States)

Sun, Shiliang; Xie, Xijiong

2016-09-01

Semisupervised learning has been an active research topic in machine learning and data mining. One main reason is that labeling examples is expensive and time-consuming, while there are large numbers of unlabeled examples available in many practical problems. So far, Laplacian regularization has been widely used in semisupervised learning. In this paper, we propose a new regularization method called tangent space intrinsic manifold regularization. It is intrinsic to data manifold and favors linear functions on the manifold. Fundamental elements involved in the formulation of the regularization are local tangent space representations, which are estimated by local principal component analysis, and the connections that relate adjacent tangent spaces. Simultaneously, we explore its application to semisupervised classification and propose two new learning algorithms called tangent space intrinsic manifold regularized support vector machines (TiSVMs) and tangent space intrinsic manifold regularized twin SVMs (TiTSVMs). They effectively integrate the tangent space intrinsic manifold regularization consideration. The optimization of TiSVMs can be solved by a standard quadratic programming, while the optimization of TiTSVMs can be solved by a pair of standard quadratic programmings. The experimental results of semisupervised classification problems show the effectiveness of the proposed semisupervised learning algorithms.

Organization of the channel-switching process in parallel computer systems based on a matrix optical switch

Science.gov (United States)

Golomidov, Y. V.; Li, S. K.; Popov, S. A.; Smolov, V. B.

1986-01-01

After a classification and analysis of electronic and optoelectronic switching devices, the design principles and structure of a matrix optical switch is described. The switching and pair-exclusion operations in this type of switch are examined, and a method for the optical switching of communication channels is elaborated. Finally, attention is given to the structural organization of a parallel computer system with a matrix optical switch.

Regularization by External Variables

DEFF Research Database (Denmark)

Bossolini, Elena; Edwards, R.; Glendinning, P. A.

2016-01-01

Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind of regula......Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind...

Very high plasma switches. Basic plasma physics and switch technology

International Nuclear Information System (INIS)

Doucet, H.J.; Roche, M.; Buzzi, J.M.

1988-01-01

A review of some high power switches recently developed for very high power technology is made with a special attention to the aspects of plasma physics involved in the mechanisms, which determine the limits of the possible switching parameters

Optically controlled redshift switching effects in hybrid fishscale metamaterials

Directory of Open Access Journals (Sweden)

Yu Wang

2018-05-01

Full Text Available We numerically demonstrate optically controlled THz response in a hybrid fishscale metamaterial with embedded photoconductive silicon at oblique incidence of TE wave. The oblique incidence allows excitation of Fano-type trapped mode resonance in a 2-fold rotational symmetric metamaterial. The hybrid fishscale metamaterial exhibits an optically controlled redshift switching effect in the THz range. The switching effect is dominated by the conductivity of the silicon instead of mechanically adjusting angles of incidence. The tuning frequency range is up to 0.3THz with a large modulation depth and high transmission in the “ON” state. The fishscale metamaterial-based switching has been experimentally verified by its microwave counterpart integrated by variable resistors. Our work provides an alternative route to realize tunable Fano-type response in metamaterials and is of importance to active manipulation, sensing and switching of THz waves in practical applications.

Regular Single Valued Neutrosophic Hypergraphs

Directory of Open Access Journals (Sweden)

Muhammad Aslam Malik

2016-12-01

Full Text Available In this paper, we define the regular and totally regular single valued neutrosophic hypergraphs, and discuss the order and size along with properties of regular and totally regular single valued neutrosophic hypergraphs. We also extend work on completeness of single valued neutrosophic hypergraphs.

Optical packet switched networks

DEFF Research Database (Denmark)

Hansen, Peter Bukhave

1999-01-01

Optical packet switched networks are investigated with emphasis on the performance of the packet switch blocks. Initially, the network context of the optical packet switched network is described showing that a packet network will provide transparency, flexibility and bridge the granularity gap...... in interferometric wavelength converters is investigated showing that a 10 Gbit/s 19 4x4 swich blocks can be cascaded at a BER of 10-14. An analytical traffic model enables the calculation of the traffice performance of a WDM packet network. Hereby the importance of WDM and wavelegth conversion in the switch blocks...... is established as a flexible means to reduce the optical buffer, e.g., the number of fibre delay lines for a 16x16 switch block is reduced from 23 to 6 by going from 2 to 8 wavelength channels pr. inlet. Additionally, a component count analysis is carried out to illustrate the trade-offs in the switch block...

Generic Switching and Non-Persistence among Medicine Users

DEFF Research Database (Denmark)

Østergaard Rathe, Jette; Andersen, Morten; Jarbøl, Dorte Ejg

2015-01-01

BACKGROUND: Generic substitution means that one medicinal product is replaced by another product containing the same active substance. It is strictly regulated with respect to its bioequivalence, and all products must have undergone appropriate studies. Although generic substitution is widely...... implemented, it still remains to be answered how generic switch influences persistence to long-term treatment, and if it is modified by patients' concerns about medicine and views on generic medicine. This study focuses on users of antidepressants and antiepileptics, and their experience of generic switching....... METHODS: The study was an observational cohort study. By use of a prescription database, we identified patients who had redeemed prescriptions on generically substitutable drugs, and a questionnaire was mailed to them. We analyzed predictors of discontinuation in relation to generic switch and patients...

Subnanosecond linear GaAs photoconductive switching: Revision 1

Energy Technology Data Exchange (ETDEWEB)

Druce, R.L.; Pocha, M.D.; Griffin, K.L.; Hofer, W.W.

1989-01-01

We are conducting research in photoconductive switching for the purpose of generating subnanosecond pulses in the 25--50kV range. We are exploiting the very fast recombination rates of Gallium Arsenide (GaAs) to explore the potential of GaAs as a closing and opening switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). The closing time of a linear GaAs switch is theoretically limited by the characteristics of the laser pulse used to activate the switch (the carrier generation time in GaAs is /approximately/10/sup /minus/14/ sec) while the opening time is theoretically limited by the recombination time of the carriers. The recombination time is several ns for commercially available semi-insulating GaAs. Doping or neutron irradiation can reduce the recombination time to less than 100 ps. We have observed switch closing times of less than 200 ps with a 100 ps duration laser pulse and opening times of less than 400 ps with neutron irradiated GaAs at fields of tens of kV/cm. The illumination source was a Nd:YAG laser operating at 1.06 /mu/m. 4 refs., 11 figs.

All-optical switching of localized surface plasmon resonance in single gold nanosandwich using GeSbTe film as an active medium

Energy Technology Data Exchange (ETDEWEB)

Hira, T.; Homma, T.; Uchiyama, T.; Kuwamura, K.; Kihara, Y.; Saiki, T. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama, Kanagawa 223-8522 (Japan)

2015-01-19

Localized surface plasmon resonance (LSPR) switching was investigated in a Au/GeSbTe/Au nanosandwich as a key active element for plasmonic integrated circuits and devices. Near-infrared single-particle spectroscopy was conducted to examine the interaction of a Au nanorod (AuNR) and Au film, between which a GeSbTe layer was incorporated as an active phase-change media. Numerical calculation revealed that hybridized modes of the AuNR and Au film exhibit a significant change of scattering intensity with the phase change. In particular, the antisymmetric (magnetic resonance) mode can be modulated effectively by the extinction coefficient of GST, as well as its refractive index. Experimental demonstration of the switching operation was performed by alternate irradiation with a picosecond pulsed laser for amorphization and a continuous wave laser for crystallization. Repeatable modulation was obtained by monitoring the scattering light around the LSPR peak at λ = 1070 nm.

dc analysis and design of zero-voltage-switched multi-resonant converters

Science.gov (United States)

Tabisz, Wojciech A.; Lee, Fred C.

Recently introduced multiresonant converters (MRCs) provide zero-voltage switching (ZVS) of both active and passive switches and offer a substantial reduction of transistor voltage stress and an increase of load range, compared to their quasi-resonant converter counterparts. Using the resonant switch concept, a simple, generalized analysis of ZVS MRCs is presented. The conversion ratio and voltage stress characteristics are derived for basic ZVS MRCs, including buck, boost, and buck/boost converters. Based on the analysis, a design procedure that optimizes the selection of resonant elements for maximum conversion efficiency is proposed.

Switching bipolar hepatic radiofrequency ablation using internally cooled wet electrodes: comparison with consecutive monopolar and switching monopolar modes

Science.gov (United States)

Yoon, J H; Woo, S; Hwang, E J; Hwang, I; Choi, W; Han, J K; Choi, B I

2015-01-01

Objective: To evaluate whether switching bipolar radiofrequency ablation (SB-RFA) using three internally cooled wet (ICW) electrodes can induce coagulations >5 cm in porcine livers with better efficiency than consecutive monopolar (CM) or switching monopolar (SM) modes. Methods: A total of 60 coagulations were made in 15 in vivo porcine livers using three 17-gauge ICW electrodes and a multichannel radiofrequency (RF) generator. RF energy (approximately 200 W) was applied in CM mode (Group A, n = 20) for 24 min, SM mode for 12 min (Group B, n = 20) or switching bipolar (SB) mode for 12 min (Group C, n = 20) in in vivo porcine livers. Thereafter, the delivered RFA energy, as well as the shape and dimension of coagulations were compared among the groups. Results: Spherical- or oval-shaped ablations were created in 30% (6/20), 85% (17/20) and 90% (18/20) of coagulations in the CM, SM and SB groups, respectively (p = 0.003). SB-RFA created ablations >5 cm in minimum diameter (Dmin) in 65% (13/20) of porcine livers, whereas SM- or CM-RFA created ablations >5 cm in only 25% (5/20) and 20% (4/20) of porcine livers, respectively (p = 0.03). The mean Dmin of coagulations was significantly larger in Group C than in Groups A and B (5.1 ± 0.9, 3.9 ± 1.2 and 4.4 ± 1.0 cm, respectively, p = 0.002) at a lower delivered RF energy level (76.8 ± 14.3, 120.9 ± 24.5 and 114.2 ± 18.3 kJ, respectively, p 5 cm in diameter with better efficiency than do SM- or CM-RFA. Advances in knowledge: SB-RFA can create large, regular ablation zones with better time–energy efficiency than do CM- or SM-RFA. PMID:25873479

Cell-type-specific genome editing with a microRNA-responsive CRISPR–Cas9 switch

Science.gov (United States)

Hirosawa, Moe; Fujita, Yoshihiko; Parr, Callum J. C.; Hayashi, Karin; Kashida, Shunnichi; Hotta, Akitsu; Woltjen, Knut

2017-01-01

Abstract The CRISPR–Cas9 system is a powerful genome-editing tool useful in a variety of biotechnology and biomedical applications. Here we developed a synthetic RNA-based, microRNA (miRNA)-responsive CRISPR–Cas9 system (miR-Cas9 switch) in which the genome editing activity of Cas9 can be modulated through endogenous miRNA signatures in mammalian cells. We created miR-Cas9 switches by using a miRNA-complementary sequence in the 5΄-UTR of mRNA encoding Streptococcus pyogenes Cas9. The miR-21-Cas9 or miR-302-Cas9 switches selectively and efficiently responded to miR-21-5p in HeLa cells or miR-302a-5p in human induced pluripotent stem cells, and post-transcriptionally attenuated the Cas9 activity only in the target cells. Moreover, the miR-Cas9 switches could differentially control the genome editing by sensing endogenous miRNA activities within a heterogeneous cell population. Our miR-Cas9 switch system provides a promising framework for cell-type selective genome editing and cell engineering based on intracellular miRNA information. PMID:28525578

On a correspondence between regular and non-regular operator monotone functions

DEFF Research Database (Denmark)

Gibilisco, P.; Hansen, Frank; Isola, T.

2009-01-01

We prove the existence of a bijection between the regular and the non-regular operator monotone functions satisfying a certain functional equation. As an application we give a new proof of the operator monotonicity of certain functions related to the Wigner-Yanase-Dyson skew information....

Optical switching systems using nanostructures

DEFF Research Database (Denmark)

Stubkjær, Kristian

2004-01-01

High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems.......High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems....

Clustering promotes switching dynamics in networks of noisy neurons

Science.gov (United States)

Franović, Igor; Klinshov, Vladimir

2018-02-01

Macroscopic variability is an emergent property of neural networks, typically manifested in spontaneous switching between the episodes of elevated neuronal activity and the quiescent episodes. We investigate the conditions that facilitate switching dynamics, focusing on the interplay between the different sources of noise and heterogeneity of the network topology. We consider clustered networks of rate-based neurons subjected to external and intrinsic noise and derive an effective model where the network dynamics is described by a set of coupled second-order stochastic mean-field systems representing each of the clusters. The model provides an insight into the different contributions to effective macroscopic noise and qualitatively indicates the parameter domains where switching dynamics may occur. By analyzing the mean-field model in the thermodynamic limit, we demonstrate that clustering promotes multistability, which gives rise to switching dynamics in a considerably wider parameter region compared to the case of a non-clustered network with sparse random connection topology.

Practical switching power supply design

CERN Document Server

Brown, Martin C

1990-01-01

Take the ""black magic"" out of switching power supplies with Practical Switching Power Supply Design! This is a comprehensive ""hands-on"" guide to the theory behind, and design of, PWM and resonant switching supplies. You'll find information on switching supply operation and selecting an appropriate topology for your application. There's extensive coverage of buck, boost, flyback, push-pull, half bridge, and full bridge regulator circuits. Special attention is given to semiconductors used in switching supplies. RFI/EMI reduction, grounding, testing, and safety standards are also deta

Improvement in the heat transfer of a gas filled thermal switch

International Nuclear Information System (INIS)

Yamamoto, J.

1984-01-01

This chapter attempts to clarify the heat transfer mechanism of a gas filled stainless steel tube, and shows how the maximum heat transfer rate is determined under various filling pressures. The thermal switch is a convenient device for a thermal link between the cold heat of a cryocooler and a magnet dewar, because the switch acts as an active thermal conductor at the precooling stage and as an insulator after collecting liquid helium in the dewar. Topics considered include the switch structure, the heat transfer process, the delay of condensation, and the precooling stage and switching. It is determined that the heat transfer mechanism of the gas filled switch is due to normal nucleate boiling at the bottom and condensation on the upper cone. The higher the initial pressure, the larger the maximum heat flow obtained. Evaporation and condensation surfaces play an important role in the heat transfer rate

Switching Phenomena

Science.gov (United States)

Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Mazza, M. G.; Kumar, P.; Plerou, V.; Preis, T.; Stokely, K.; Xu, L.

One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines can suddenly "switch" from one behavior to another, even though they possess no perfect metronome in time. As if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many temporal patterns in physics, economics, and medicine and even begin to characterize the switching phenomena that enable a system to pass from one state to another. We discuss some applications of correlated randomness to understanding switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water's anomalies are related to a switching point (which is not unlike the "tipping point" immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not "outliers" (another Gladwell immortalization).

Stochastic analytic regularization

International Nuclear Information System (INIS)

Alfaro, J.

1984-07-01

Stochastic regularization is reexamined, pointing out a restriction on its use due to a new type of divergence which is not present in the unregulated theory. Furthermore, we introduce a new form of stochastic regularization which permits the use of a minimal subtraction scheme to define the renormalized Green functions. (author)

The importance of the rotor in hydrazone-based molecular switches

Directory of Open Access Journals (Sweden)

Xin Su

2012-06-01

Full Text Available The pH-activated E/Z isomerization of a series of hydrazone-based systems having different functional groups as part of the rotor (R = COMe, CN, Me, H, was studied. The switching efficiency of these systems was compared to that of a hydrazone-based molecular switch (R = COOEt whose E/Z isomerization is fully reversible. It was found that the nature of the R group is critical for efficient switching to occur; the R group should be a moderate H-bond acceptor in order to (i provide enough driving force for the rotor to move upon protonation, and (ii stabilize the obtained Z configuration, to achieve full conversion.

Optimization of multi-branch switched diversity systems

KAUST Repository

Nam, Haewoon

2009-10-01

A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold, the optimal switching threshold is a function of both the average channel SNR and the number of diversity branches, where computing the optimal switching threshold is not a simple task when the number of diversity branches is high. The newly proposed multi-branch switched diversity system is based on a sequence of switching thresholds, instead of a single switching threshold, where a different diversity branch uses a different switching threshold for signal comparison. Thanks to the fact that each switching threshold in the sequence can be optimized only based on the number of the remaining diversity branches, the proposed system makes it easy to find these switching thresholds. Furthermore, some selected numerical and simulation results show that the proposed switched diversity system with the sequence of optimal switching thresholds outperforms the conventional system with the single optimal switching threshold. © 2009 IEEE.

Hybrid switch for resonant power converters

Science.gov (United States)

Lai, Jih-Sheng; Yu, Wensong

2014-09-09

A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

Investigation of fatigue behavior of Pb(Zr0.45Ti0.55)O3 thin films under asymmetric polarization switching

Science.gov (United States)

Zhu, Hui; Chen, Yueyuan; Chu, Daping; Feng, Shiwei; Zhang, Yingqiao; Wang, Pengfei

2016-09-01

The fatigue of lead zirconate titanate (PZT) thin films was measured under repetitive switching using asymmetric square waves. The remnant polarization and coercive voltage were found to present regular changes in the initial 10 s, independent of the asymmetry or frequency of switching waves. We attributed the change to the relaxation of stress in the film and identified a coercive voltage V 0 of 0.6 V for the stress-free film. By comparing the coercive voltage and V 0, we found that a built-in electric field was induced by asymmetric switching, where the direction and magnitude were dependent on the degree of waveform asymmetry. Furthermore, the fatigue speed was suggested to be closely related to the generation rate of oxygen vacancies. It was confirmed by our result that a faster decay of remnant polarization can be obtained by applying square waves with a higher degree of asymmetry or symmetry of square waves with a lower frequency.

Tutorial: Integrated-photonic switching structures

Science.gov (United States)

Soref, Richard

2018-02-01

Recent developments in waveguided 2 × 2 and N × M photonic switches are reviewed, including both broadband and narrowband resonant devices for the Si, InP, and AlN platforms. Practical actuation of switches by electro-optical and thermo-optical techniques is discussed. Present datacom-and-computing applications are reviewed, and potential applications are proposed for chip-scale photonic and optoelectronic integrated switching networks. Potential is found in the reconfigurable, programmable "mesh" switches that enable a promising group of applications in new areas beyond those in data centers and cloud servers. Many important matrix switches use gated semiconductor optical amplifiers. The family of broadband, directional-coupler 2 × 2 switches featuring two or three side-coupled waveguides deserves future experimentation, including devices that employ phase-change materials. The newer 2 × 2 resonant switches include standing-wave resonators, different from the micro-ring traveling-wave resonators. The resonant devices comprise nanobeam interferometers, complex-Bragg interferometers, and asymmetric contra-directional couplers. Although the fast, resonant devices offer ultralow switching energy, ˜1 fJ/bit, they have limitations. They require several trade-offs when deployed, but they do have practical application.

A binary-decision-diagram-based two-bit arithmetic logic unit on a GaAs-based regular nanowire network with hexagonal topology

International Nuclear Information System (INIS)

Zhao Hongquan; Kasai, Seiya; Shiratori, Yuta; Hashizume, Tamotsu

2009-01-01

A two-bit arithmetic logic unit (ALU) was successfully fabricated on a GaAs-based regular nanowire network with hexagonal topology. This fundamental building block of central processing units can be implemented on a regular nanowire network structure with simple circuit architecture based on graphical representation of logic functions using a binary decision diagram and topology control of the graph. The four-instruction ALU was designed by integrating subgraphs representing each instruction, and the circuitry was implemented by transferring the logical graph structure to a GaAs-based nanowire network formed by electron beam lithography and wet chemical etching. A path switching function was implemented in nodes by Schottky wrap gate control of nanowires. The fabricated circuit integrating 32 node devices exhibits the correct output waveforms at room temperature allowing for threshold voltage variation.

Controlling friction in a manganite surface by resistive switching

OpenAIRE

Schmidt, Hendrik; Krisponeit, Jon-Olaf; Samwer, Konrad; Volkert, Cynthia A.

2016-01-01

We report a significant change in friction of a $\\rm La_{0.55}Ca_{0.45}MnO_3$ thin film measured as a function of the materials resistive state under ultrahigh vacuum conditions at room temperature by friction force microscopy. While friction is high in the insulating state, it clearly changes to lower values if the probed local region is switched to the conducting state via nanoscale resistance switching. Thus we demonstrate active control of friction without having to change the temperature...

Generalized Multi-Cell Switched-Inductor and Switched-Capacitor Z-source Inverters

DEFF Research Database (Denmark)

Li, Ding; Chiang Loh, Poh; Zhu, Miao

2013-01-01

. Their boosting gains are, therefore, limited in practice. To overcome these shortcomings, the generalized switched-inductor and switched-capacitor Z-source inverters are proposed, whose extra boosting abilities and other advantages have already been verified in simulation and experiment....

Moonstruck primates: owl monkeys (Aotus need moonlight for nocturnal activity in their natural environment.

Directory of Open Access Journals (Sweden)

Eduardo Fernández-Duque

2010-09-01

Full Text Available Primates show activity patterns ranging from nocturnality to diurnality, with a few species showing activity both during day and night. Among anthropoids (monkeys, apes and humans, nocturnality is only present in the Central and South American owl monkey genus Aotus. Unlike other tropical Aotus species, the Azara's owl monkeys (A. azarai of the subtropics have switched their activity pattern from strict nocturnality to one that also includes regular diurnal activity. Harsher climate, food availability, and the lack of predators or diurnal competitors, have all been proposed as factors favoring evolutionary switches in primate activity patterns. However, the observational nature of most field studies has limited an understanding of the mechanisms responsible for this switch in activity patterns. The goal of our study was to evaluate the hypothesis that masking, namely the stimulatory and/or inhibitory/disinhibitory effects of environmental factors on synchronized circadian locomotor activity, is a key determinant of the unusual activity pattern of Azara's owl monkeys. We use continuous long-term (6-18 months 5-min-binned activity records obtained with actimeter collars fitted to wild owl monkeys (n =  10 individuals to show that this different pattern results from strong masking of activity by the inhibiting and enhancing effects of ambient luminance and temperature. Conclusive evidence for the direct masking effect of light is provided by data showing that locomotor activity was almost completely inhibited when moonlight was shadowed during three lunar eclipses. Temperature also negatively masked locomotor activity, and this masking was manifested even under optimal light conditions. Our results highlight the importance of the masking of circadian rhythmicity as a determinant of nocturnality in wild owl monkeys and suggest that the stimulatory effects of dim light in nocturnal primates may have been selected as an adaptive response to

Switch on the competition. Causes, consequences and policy implications of consumer switching costs

International Nuclear Information System (INIS)

Pomp, M.; Shestalova, V.; Rangel, L.

2005-09-01

The success or failure of reforms aimed at liberalising markets depends to an important degree on consumer behaviour. If consumers do not base their choices on differences in prices and quality, competition between firms may be weak and the benefits of liberalisation to consumers may be small. One possible reason why consumers may respond only weakly to differences in price and quality is high costs of switching to another firm. This report presents a framework for analysing markets with switching costs and applies the framework in two empirical case studies. The first case study analyses the residential energy market, the second focuses on the market for social health insurance. In both markets, there are indications that switching costs are substantial. The report discusses policy options for reducing switching costs and for alleviating the consequences of switching costs

Switch on the competition. Causes, consequences and policy implications of consumer switching costs

Energy Technology Data Exchange (ETDEWEB)

Pomp, M.; Shestalova, V.; Rangel, L.

2005-09-15

The success or failure of reforms aimed at liberalising markets depends to an important degree on consumer behaviour. If consumers do not base their choices on differences in prices and quality, competition between firms may be weak and the benefits of liberalisation to consumers may be small. One possible reason why consumers may respond only weakly to differences in price and quality is high costs of switching to another firm. This report presents a framework for analysing markets with switching costs and applies the framework in two empirical case studies. The first case study analyses the residential energy market, the second focuses on the market for social health insurance. In both markets, there are indications that switching costs are substantial. The report discusses policy options for reducing switching costs and for alleviating the consequences of switching costs.

Electrically tunable sign of capacitance in planar W-doped vanadium dioxide micro-switches

Directory of Open Access Journals (Sweden)

Mohammed Soltani, Mohamed Chaker and Joelle Margot

2011-01-01

Full Text Available Negative capacitance (NC in a planar W-doped VO2 micro-switch was observed at room temperature in the low-frequency range 1 kHz–10 MHz. The capacitance changed from positive to negative values as the W-doped VO2 active layer switched from semiconducting to metallic state under applied voltage. In addition, a capacitance–voltage hysteresis was observed as the applied voltage was cycled from −35 to 35 V. These observations suggest that NC results from the increase of the electrically induced conductivity in the active layer. This NC phenomenon could be exploited in advanced multifunctional devices including ultrafast switches, field-effect transistors and memcapacitive systems.

Software Defined Networking (SDN) controlled all optical switching networks with multi-dimensional switching architecture

Science.gov (United States)

Zhao, Yongli; Ji, Yuefeng; Zhang, Jie; Li, Hui; Xiong, Qianjin; Qiu, Shaofeng

2014-08-01

Ultrahigh throughout capacity requirement is challenging the current optical switching nodes with the fast development of data center networks. Pbit/s level all optical switching networks need to be deployed soon, which will cause the high complexity of node architecture. How to control the future network and node equipment together will become a new problem. An enhanced Software Defined Networking (eSDN) control architecture is proposed in the paper, which consists of Provider NOX (P-NOX) and Node NOX (N-NOX). With the cooperation of P-NOX and N-NOX, the flexible control of the entire network can be achieved. All optical switching network testbed has been experimentally demonstrated with efficient control of enhanced Software Defined Networking (eSDN). Pbit/s level all optical switching nodes in the testbed are implemented based on multi-dimensional switching architecture, i.e. multi-level and multi-planar. Due to the space and cost limitation, each optical switching node is only equipped with four input line boxes and four output line boxes respectively. Experimental results are given to verify the performance of our proposed control and switching architecture.

Electromechanical magnetization switching

Energy Technology Data Exchange (ETDEWEB)

Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)

2015-03-14

We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

Electromechanical magnetization switching

International Nuclear Information System (INIS)

Chudnovsky, Eugene M.; Jaafar, Reem

2015-01-01

We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained

JUNOS Enterprise Switching

CERN Document Server

Reynolds, Harry

2009-01-01

JUNOS Enterprise Switching is the only detailed technical book on Juniper Networks' new Ethernet-switching EX product platform. With this book, you'll learn all about the hardware and ASIC design prowess of the EX platform, as well as the JUNOS Software that powers it. Not only is this extremely practical book a useful, hands-on manual to the EX platform, it also makes an excellent study guide for certification exams in the JNTCP enterprise tracks. The authors have based JUNOS Enterprise Switching on their own Juniper training practices and programs, as well as the configuration, maintenanc

Cell-type-specific genome editing with a microRNA-responsive CRISPR-Cas9 switch.

Science.gov (United States)

Hirosawa, Moe; Fujita, Yoshihiko; Parr, Callum J C; Hayashi, Karin; Kashida, Shunnichi; Hotta, Akitsu; Woltjen, Knut; Saito, Hirohide

2017-07-27

The CRISPR-Cas9 system is a powerful genome-editing tool useful in a variety of biotechnology and biomedical applications. Here we developed a synthetic RNA-based, microRNA (miRNA)-responsive CRISPR-Cas9 system (miR-Cas9 switch) in which the genome editing activity of Cas9 can be modulated through endogenous miRNA signatures in mammalian cells. We created miR-Cas9 switches by using a miRNA-complementary sequence in the 5΄-UTR of mRNA encoding Streptococcus pyogenes Cas9. The miR-21-Cas9 or miR-302-Cas9 switches selectively and efficiently responded to miR-21-5p in HeLa cells or miR-302a-5p in human induced pluripotent stem cells, and post-transcriptionally attenuated the Cas9 activity only in the target cells. Moreover, the miR-Cas9 switches could differentially control the genome editing by sensing endogenous miRNA activities within a heterogeneous cell population. Our miR-Cas9 switch system provides a promising framework for cell-type selective genome editing and cell engineering based on intracellular miRNA information. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Grammatical encoding in bilingual language production: A focus on code switching

Directory of Open Access Journals (Sweden)

MEHDI ePURMOHAMMAD

2015-11-01

Full Text Available I report three experiments that examined whether words from one language of bilinguals can use the syntactic features form the other language and how such syntactic co-activation might influence syntactic processing. In other words, I examined whether there are any cases in which a lexical item inhibits its inherent syntactic feature and uses the syntactic feature(s that belongs to the other language, instead. In the non-switch condition in experiment 1 and 2, Persian-English bilinguals described pictures using an adjective-noun string from the same language requested. In the switch condition, they used the nouns and adjectives from the other language. In Experiment 3, in the switch condition participants used only the adjectives of noun phrases from the other language. The results showed that bilinguals may inhibit the activation of a word’s syntactic feature and use the syntactic property from the other language instead (e.g., pirāhane (N black. As the combinatorial node (the node that specify different kinds of syntactic structures in which a word can be used of a used adjective retains activation at least temporarily, bilinguals are more likely to use the same combinatorial node even for an adjective from the other language. Using the syntactic features from the other language increased in the switch conditions. Moreover, more inappropriate responses observed when switching from bilinguals’ L2 to L1. The results also revealed that different experimental contexts may lead to different patterns of the control mechanism. The results will be interpreted in terms of Hartsuiker and Pickering’s (2008 model of syntactic representation

Design of a Command-Triggered Plasma Opening Switch for Terawatt Applications

International Nuclear Information System (INIS)

Savage, Mark E.; Mendel, C.W.; Seidel, David B.

1999-01-01

Inductive energy storage systems can have high energy density, lending to smaller, less expensive systems. The crucial element of an inductive energy storage system is the opening switch. This switch must conduct current while energy is stored in an inductor, then open quickly to transfer this energy to a load. Plasma can perform this function. The Plasma Opening Switch (POS) has been studied for more than two decades. Success with the conventional plasma opening switch has been limited. A system designed to significantly improve the performance of vacuum opening switches is described in this paper. The gap cleared of plasma is a rough figure-of-merit for vacuum opening switches. Typical opened gaps of 3 mm are reported for conventional switches. The goal for the system described in this paper is more than 3 cm. To achieve this, the command-triggered POS adds an active opening mechanism, which allows complete separation of conduction and opening. This separation is advantageous because of the widely different time scales of conduction and opening. The detrimental process of magnetic field penetration into the plasma during conduction is less important in this switch. The opening mechanism duration is much shorter than the conduction time, so penetration during opening is insignificant. Opening is accomplished with a fast magnetic field that pushes plasma out of the switch region. Plasma must be removed from the switch region to allow high voltage. This paper describes some processes important during conduction and opening, and show calculations on the trigger requirements. The design of the switch is shown. This system is designed to demonstrate both improved performance and nanosecond output jitter at levels greater than one terawatt. An amplification mechanism is described which reduces the trigger energy. Particle-in-cell simulations of the system are also shown

Effective field theory dimensional regularization

International Nuclear Information System (INIS)

Lehmann, Dirk; Prezeau, Gary

2002-01-01

A Lorentz-covariant regularization scheme for effective field theories with an arbitrary number of propagating heavy and light particles is given. This regularization scheme leaves the low-energy analytic structure of Greens functions intact and preserves all the symmetries of the underlying Lagrangian. The power divergences of regularized loop integrals are controlled by the low-energy kinematic variables. Simple diagrammatic rules are derived for the regularization of arbitrary one-loop graphs and the generalization to higher loops is discussed

Effective field theory dimensional regularization

Science.gov (United States)

Lehmann, Dirk; Prézeau, Gary

2002-01-01

A Lorentz-covariant regularization scheme for effective field theories with an arbitrary number of propagating heavy and light particles is given. This regularization scheme leaves the low-energy analytic structure of Greens functions intact and preserves all the symmetries of the underlying Lagrangian. The power divergences of regularized loop integrals are controlled by the low-energy kinematic variables. Simple diagrammatic rules are derived for the regularization of arbitrary one-loop graphs and the generalization to higher loops is discussed.

Copper oxide resistive switching memory for e-textile

Directory of Open Access Journals (Sweden)

Jin-Woo Han

2011-09-01

Full Text Available A resistive switching memory suitable for integration into textiles is demonstrated on a copper wire network. Starting from copper wires, a Cu/CuxO/Pt sandwich structure is fabricated. The active oxide film is produced by simple thermal oxidation of Cu in atmospheric ambient. The devices display a resistance switching ratio of 102 between the high and low resistance states. The memory states are reversible and retained over 107 seconds, with the states remaining nondestructive after multiple read operations. The presented device on the wire network can potentially offer a memory for integration into smart textile.

Static magnetism and thermal switching in randomly oriented L10 FePt thin films

Science.gov (United States)

Lisfi, A.; Pokharel, S.; Alqarni, A.; Akioya, O.; Morgan, W.; Wuttig, M.

2018-05-01

Static magnetism and thermally activated magnetic relaxation were investigated in granular FePt films (20 nm-200 nm thick) with random magnetic anisotropy through hysteresis loop, torque curve and magnetization time dependence measurements. While the magnetism of thicker film (200 nm thick) is dominated by a single switching of the ordered L10 phase, thinner film (20 nm) displays a double switching, which is indicative of the presence of the disordered cubic phase. The pronounced behavior of double switching in thinner film suggests that the film grain boundary is composed of soft cubic magnetic phase. The magnetic relaxation study reveals that magnetic viscosity S of the films is strongly dependent on the external applied field and exhibits a maximum value (12 kAm) around the switching field and a vanishing behavior at low (1 kOe) and large (12 kOe) fields. The activation volume of the thermal switching was found to be much smaller than the physical volume of the granular structure due to the incoherent rotation mode of the magnetization reversal mechanism, which is established to be domain wall nucleation.

Elements of magnetic switching

International Nuclear Information System (INIS)

Aaland, K.

1983-01-01

This chapter describes magnetic switching as a method of connecting a capacitor bank (source) to a load; reviews several successful applications of magnetic switching, and discusses switching transformers, limitations and future possibilities. Some of the inflexibility and especially the high cost of magnetic materials may be overcome with the availability of the new splash cooled ribbons (Metglas). Experience has shown that magnetics works despite shock, radiation or noise interferences

Hierarchical regular small-world networks

International Nuclear Information System (INIS)

Boettcher, Stefan; Goncalves, Bruno; Guclu, Hasan

2008-01-01

Two new networks are introduced that resemble small-world properties. These networks are recursively constructed but retain a fixed, regular degree. They possess a unique one-dimensional lattice backbone overlaid by a hierarchical sequence of long-distance links, mixing real-space and small-world features. Both networks, one 3-regular and the other 4-regular, lead to distinct behaviors, as revealed by renormalization group studies. The 3-regular network is planar, has a diameter growing as √N with system size N, and leads to super-diffusion with an exact, anomalous exponent d w = 1.306..., but possesses only a trivial fixed point T c = 0 for the Ising ferromagnet. In turn, the 4-regular network is non-planar, has a diameter growing as ∼2 √(log 2 N 2 ) , exhibits 'ballistic' diffusion (d w = 1), and a non-trivial ferromagnetic transition, T c > 0. It suggests that the 3-regular network is still quite 'geometric', while the 4-regular network qualifies as a true small world with mean-field properties. As an engineering application we discuss synchronization of processors on these networks. (fast track communication)

Know-How on design of switching regulator

International Nuclear Information System (INIS)

1985-08-01

This book introduces switching regulator from base to application, which deals with fundamentals of switching regulator such as the reason of boom about switching regulator, understanding simple circuit without electric transformer and decision of circuit type with input voltage and output voltage, configuration and characteristic of switching regulator, a concrete design of switching regulator, pulse width control circuit and protection circuit, concrete circuit examples of switching power and the point of switching regulator.

Mediator facilitates transcriptional activation and dynamic long-range contacts at the IgH locus during class switch recombination.

Science.gov (United States)

Thomas-Claudepierre, Anne-Sophie; Robert, Isabelle; Rocha, Pedro P; Raviram, Ramya; Schiavo, Ebe; Heyer, Vincent; Bonneau, Richard; Luo, Vincent M; Reddy, Janardan K; Borggrefe, Tilman; Skok, Jane A; Reina-San-Martin, Bernardo

2016-03-07

Immunoglobulin (Ig) class switch recombination (CSR) is initiated by the transcription-coupled recruitment of activation-induced cytidine deaminase (AID) to Ig switch regions (S regions). During CSR, the IgH locus undergoes dynamic three-dimensional structural changes in which promoters, enhancers, and S regions are brought to close proximity. Nevertheless, little is known about the underlying mechanisms. In this study, we show that Med1 and Med12, two subunits of the mediator complex implicated in transcription initiation and long-range enhancer/promoter loop formation, are dynamically recruited to the IgH locus enhancers and the acceptor regions during CSR and that their knockdown in CH12 cells results in impaired CSR. Furthermore, we show that conditional inactivation of Med1 in B cells results in defective CSR and reduced acceptor S region transcription. Finally, we show that in B cells undergoing CSR, the dynamic long-range contacts between the IgH enhancers and the acceptor regions correlate with Med1 and Med12 binding and that they happen at a reduced frequency in Med1-deficient B cells. Our results implicate the mediator complex in the mechanism of CSR and are consistent with a model in which mediator facilitates the long-range contacts between S regions and the IgH locus enhancers during CSR and their transcriptional activation. © 2016 Thomas-Claudepierre et al.

75 FR 76006 - Regular Meeting

Science.gov (United States)

2010-12-07

... FARM CREDIT SYSTEM INSURANCE CORPORATION Regular Meeting AGENCY: Farm Credit System Insurance Corporation Board. ACTION: Regular meeting. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). Date and Time: The meeting of the Board will be held...

MENGAPA PERUSAHAAN MELAKUKAN AUDITOR SWITCH?

Directory of Open Access Journals (Sweden)

Kadek Sumadi

2011-01-01

Full Text Available The existence of a large number of accounting firms allowsprovides companies choices whether to stay with current firm or switchto another accounting firm. Decision of Minister of FinanceNo.423/KMK.06/2002 states that a company must switch auditor afterfive years of consecutive assignment. This is mandatory. The questionrises when a company voluntarily switches its auditor. Why does thishappen?One of the reasons is that management does not satisfy withauditor opinion, except for unqualified opinion. New management teamwould directly or indirectly encourage auditor switch to align accountingand reporting policies. Moreover an expanding company expects positivereaction when it does auditor switch. Profitability is also one reason fora company to switch auditor, for example, when a company earns moreprofit it tends to hire more credible auditor. On the other hand, when thecompany faces a financial distress, it probably would switch auditor aswell.

Comparison of Ion Beam opening switch and plasma opening switch performance

International Nuclear Information System (INIS)

Greenly, J.R.; Rondeau, G.D.; Sheldon, H.T.; Dreike, P.L.

1986-01-01

The Ion Beam opening switch (IBOS) experiment has shown that an intense charge-neutralized ion beam can carry current across a vacuum magnetically-insulated transmission line and then transfer that current to a downstream load quickly. In the IBOS experiment, a 10 cm wide parallel plate transmission line was fed up to 100 kA peak current by a 4Ω, 100 ns pulser. An ion beam of up to 100 A/cm/sup 2/, 100-300 keV protons or carbon was injected through the anode of the line in a 10 cm x 10 cm region. The line terminated in either a 15 nH short circuit or an electron diode with variable gap. The ion beam switch was able to carry up to 70 kA of line current before load current began to flow. This model is also quantitatively consistent with the observation that switch conduction current is not linear with either injected ion beam current or switch area

General inverse problems for regular variation

DEFF Research Database (Denmark)

Damek, Ewa; Mikosch, Thomas Valentin; Rosinski, Jan

2014-01-01

Regular variation of distributional tails is known to be preserved by various linear transformations of some random structures. An inverse problem for regular variation aims at understanding whether the regular variation of a transformed random object is caused by regular variation of components ...

Principles of broadband switching and networking

CERN Document Server

Liew, Soung C

2010-01-01

An authoritative introduction to the roles of switching and transmission in broadband integrated services networks Principles of Broadband Switching and Networking explains the design and analysis of switch architectures suitable for broadband integrated services networks, emphasizing packet-switched interconnection networks with distributed routing algorithms. The text examines the mathematical properties of these networks, rather than specific implementation technologies. Although the pedagogical explanations in this book are in the context of switches, many of the fundamenta

Identification and Characterization of Wor4, a New Transcriptional Regulator of White-Opaque Switching

Directory of Open Access Journals (Sweden)

Matthew B. Lohse

2016-03-01

Full Text Available The human fungal pathogen Candida albicans can switch between two cell types, “white” and “opaque,” each of which is heritable through many cell divisions. Switching between these two cell types is regulated by six transcriptional regulators that form a highly interconnected circuit with multiple feedback loops. Here, we identify a seventh regulator of white-opaque switching, which we have named Wor4. We show that ectopic expression of Wor4 is sufficient to drive switching from the white to the opaque cell type, and that deletion of Wor4 blocks switching from the white to the opaque cell type. A combination of ectopic expression and deletion experiments indicates that Wor4 is positioned upstream of Wor1, and that it is formally an activator of the opaque cell type. The combination of ectopic expression and deletion phenotypes for Wor4 is unique; none of the other six white-opaque regulators show this pattern. We determined the pattern of Wor4 binding across the genome by ChIP-seq and found it is highly correlated with that of Wor1 and Wor2, indicating that Wor4 is tightly integrated into the existing white-opaque regulatory circuit. We previously proposed that white-to-opaque switching relies on the activation of a complex circuit of feedback loops that remains excited through many cell divisions. The identification of a new, central regulator of white-opaque switching supports this idea by indicating that the white-opaque switching mechanism is considerably more complex than those controlling conventional, nonheritable patterns of gene expression.

Error rate degradation due to switch crosstalk in large modular switched optical networks

DEFF Research Database (Denmark)

Saxtoft, Christian; Chidgey, P.

1993-01-01

A theoretical model of an optical network incorporating wavelength selective elements, amplifiers, couplers and switches is presented. The model is used to evaluate a large modular switch optical network that provides the capability of adapting easily to changes in network traffic requirements. T....... The network dimensions are shown to be limited by the optical crosstalk in the switch matrices and by the polarization dependent loss in the optical components...

Pemodelan Markov Switching Autoregressive

OpenAIRE

Ariyani, Fiqria Devi; Warsito, Budi; Yasin, Hasbi

2014-01-01

Transition from depreciation to appreciation of exchange rate is one of regime switching that ignored by classic time series model, such as ARIMA, ARCH, or GARCH. Therefore, economic variables are modeled by Markov Switching Autoregressive (MSAR) which consider the regime switching. MLE is not applicable to parameters estimation because regime is an unobservable variable. So that filtering and smoothing process are applied to see the regime probabilities of observation. Using this model, tran...

Software-defined networking control plane for seamless integration of multiple silicon photonic switches in Datacom networks.

Science.gov (United States)

Shen, Yiwen; Hattink, Maarten H N; Samadi, Payman; Cheng, Qixiang; Hu, Ziyiz; Gazman, Alexander; Bergman, Keren

2018-04-16

Silicon photonics based switches offer an effective option for the delivery of dynamic bandwidth for future large-scale Datacom systems while maintaining scalable energy efficiency. The integration of a silicon photonics-based optical switching fabric within electronic Datacom architectures requires novel network topologies and arbitration strategies to effectively manage the active elements in the network. We present a scalable software-defined networking control plane to integrate silicon photonic based switches with conventional Ethernet or InfiniBand networks. Our software-defined control plane manages both electronic packet switches and multiple silicon photonic switches for simultaneous packet and circuit switching. We built an experimental Dragonfly network testbed with 16 electronic packet switches and 2 silicon photonic switches to evaluate our control plane. Observed latencies occupied by each step of the switching procedure demonstrate a total of 344 µs control plane latency for data-center and high performance computing platforms.

Energy losses in switches

International Nuclear Information System (INIS)

Martin, T.H.; Seamen, J.F.; Jobe, D.O.

1993-01-01

The authors experiments show energy losses between 2 and 10 times that of the resistive time predictions. The experiments used hydrogen, helium, air, nitrogen, SF 6 polyethylene, and water for the switching dielectric. Previously underestimated switch losses have caused over predicting the accelerator outputs. Accurate estimation of these losses is now necessary for new high-efficiency pulsed power devices where the switching losses constitute the major portion of the total energy loss. They found that the switch energy losses scale as (V peak I peak ) 1.1846 . When using this scaling, the energy losses in any of the tested dielectrics are almost the same. This relationship is valid for several orders of magnitude and suggested a theoretical basis for these results. Currents up to .65 MA, with voltages to 3 MV were applied to various gaps during these experiments. The authors data and the developed theory indicates that the switch power loss continues for a much longer time than the resistive time, with peak power loss generally occurring at peak current in a ranging discharge instead of the early current time. All of the experiments were circuit code modeled after developing a new switch loss version based on the theory. The circuit code predicts switch energy loss and peak currents as a function of time. During analysis of the data they noticed slight constant offsets between the theory and data that depended on the dielectric. They modified the plasma conductivity for each tested dielectric to lessen this offset

Software Switching for Data Acquisition

CERN Multimedia

CERN. Geneva; Malone, David

2016-01-01

In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

Low-Voltage Switched-Capacitor Circuits

DEFF Research Database (Denmark)

Bidari, E.; Keskin, M.; Maloberti, F.

1999-01-01

Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications.......Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

Molecular switches at the synapse emerge from receptor and kinase traffic.

Directory of Open Access Journals (Sweden)

2005-07-01

Full Text Available Changes in the synaptic connection strengths between neurons are believed to play a role in memory formation. An important mechanism for changing synaptic strength is through movement of neurotransmitter receptors and regulatory proteins to and from the synapse. Several activity-triggered biochemical events control these movements. Here we use computer models to explore how these putative memory-related changes can be stabilised long after the initial trigger, and beyond the lifetime of synaptic molecules. We base our models on published biochemical data and experiments on the activity-dependent movement of a glutamate receptor, AMPAR, and a calcium-dependent kinase, CaMKII. We find that both of these molecules participate in distinct bistable switches. These simulated switches are effective for long periods despite molecular turnover and biochemical fluctuations arising from the small numbers of molecules in the synapse. The AMPAR switch arises from a novel self-recruitment process where the presence of sufficient receptors biases the receptor movement cycle to insert still more receptors into the synapse. The CaMKII switch arises from autophosphorylation of the kinase. The switches may function in a tightly coupled manner, or relatively independently. The latter case leads to multiple stable states of the synapse. We propose that similar self-recruitment cycles may be important for maintaining levels of many molecules that undergo regulated movement, and that these may lead to combinatorial possible stable states of systems like the synapse.

Bootstrapped Low-Voltage Analog Switches

DEFF Research Database (Denmark)

Steensgaard-Madsen, Jesper

1999-01-01

Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...

Ikaros controls isotype selection during immunoglobulin class switch recombination.

Science.gov (United States)

Sellars, MacLean; Reina-San-Martin, Bernardo; Kastner, Philippe; Chan, Susan

2009-05-11

Class switch recombination (CSR) allows the humoral immune response to exploit different effector pathways through specific secondary antibody isotypes. However, the molecular mechanisms and factors that control immunoglobulin (Ig) isotype choice for CSR are unclear. We report that deficiency for the Ikaros transcription factor results in increased and ectopic CSR to IgG(2b) and IgG(2a), and reduced CSR to all other isotypes, regardless of stimulation. Ikaros suppresses active chromatin marks, transcription, and activation-induced cytidine deaminase (AID) accessibility at the gamma2b and gamma2a genes to inhibit class switching to these isotypes. Further, Ikaros directly regulates isotype gene transcription as it directly binds the Igh 3' enhancer and interacts with isotype gene promoters. Finally, Ikaros-mediated repression of gamma2b and gamma2a transcription promotes switching to other isotype genes by allowing them to compete for AID-mediated recombination at the single-cell level. Thus, our results reveal transcriptional competition between constant region genes in individual cells to be a critical and general mechanism for isotype specification during CSR. We show that Ikaros is a master regulator of this competition.

Characteristics of magnetic switch used as main switch of solid-state accelerator

International Nuclear Information System (INIS)

Li Song; Qian Baoliang; Yang Hanwu; Meng Zhipeng; Yang Shi

2012-01-01

In order to improve the performance of solid-state accelerator, the characteristics of magnetic switch used as the main switch of the accelerator have been investigated. The volume of magnetic core, the loss, and saturated inductance of the magnetic switch have been derived. The results show that the spacing factor of the magnetic switch reaches the peak when the height of the magnetic materials is 0.05 m for selected magnetic cores. The saturated inductance of the windings changes slowly when the average magnetic path length of the core is greater than 1 m. The physical process of saturation in the cores was analyzed by using saturation-wave theory. The rise-time factor of the output pulse was derived. The thickness, resistivity and magnetic path length difference of the magnetic core are shown to be key parameters affecting the rise-time factor. (authors)

Nonlinear-Based MEMS Sensors and Active Switches for Gas and Acceleration Applications

KAUST Repository

Younis, Mohammad I.

2016-01-01

what is called smart switches triggered by the detection of a desirable physical quantity. The concept aims to reduce the complexity of systems that rely on controllers and complex algorithms to realize on-demand trigger actions. In the first part

Continuum-regularized quantum gravity

International Nuclear Information System (INIS)

Chan Huesum; Halpern, M.B.

1987-01-01

The recent continuum regularization of d-dimensional Euclidean gravity is generalized to arbitrary power-law measure and studied in some detail as a representative example of coordinate-invariant regularization. The weak-coupling expansion of the theory illustrates a generic geometrization of regularized Schwinger-Dyson rules, generalizing previous rules in flat space and flat superspace. The rules are applied in a non-trivial explicit check of Einstein invariance at one loop: the cosmological counterterm is computed and its contribution is included in a verification that the graviton mass is zero. (orig.)

Vestigialization of an Allosteric Switch: Genetic and Structural Mechanisms for the Evolution of Constitutive Activity in a Steroid Hormone Receptor

Science.gov (United States)

Bridgham, Jamie T.; Keay, June; Ortlund, Eric A.; Thornton, Joseph W.

2014-01-01

An important goal in molecular evolution is to understand the genetic and physical mechanisms by which protein functions evolve and, in turn, to characterize how a protein's physical architecture influences its evolution. Here we dissect the mechanisms for an evolutionary shift in function in the mollusk ortholog of the steroid hormone receptors (SRs), a family of biologically essential transcription factors. In vertebrates, the activity of SRs allosterically depends on binding a hormonal ligand; in mollusks, however, the SR ortholog (called ER, because of high sequence similarity to vertebrate estrogen receptors) activates transcription in the absence of ligand and does not respond to steroid hormones. To understand how this shift in regulation evolved, we combined evolutionary, structural, and functional analyses. We first determined the X-ray crystal structure of the ER of the Pacific oyster Crassostrea gigas (CgER), and found that its ligand pocket is filled with bulky residues that prevent ligand occupancy. To understand the genetic basis for the evolution of mollusk ERs' unique functions, we resurrected an ancient SR progenitor and characterized the effect of historical amino acid replacements on its functions. We found that reintroducing just two ancient replacements from the lineage leading to mollusk ERs recapitulates the evolution of full constitutive activity and the loss of ligand activation. These substitutions stabilize interactions among key helices, causing the allosteric switch to become “stuck” in the active conformation and making activation independent of ligand binding. Subsequent changes filled the ligand pocket without further affecting activity; by degrading the allosteric switch, these substitutions vestigialized elements of the protein's architecture required for ligand regulation and made reversal to the ancestral function more complex. These findings show how the physical architecture of allostery enabled a few large-effect mutations

Vestigialization of an allosteric switch: genetic and structural mechanisms for the evolution of constitutive activity in a steroid hormone receptor.

Directory of Open Access Journals (Sweden)

Jamie T Bridgham

2014-01-01

Full Text Available An important goal in molecular evolution is to understand the genetic and physical mechanisms by which protein functions evolve and, in turn, to characterize how a protein's physical architecture influences its evolution. Here we dissect the mechanisms for an evolutionary shift in function in the mollusk ortholog of the steroid hormone receptors (SRs, a family of biologically essential transcription factors. In vertebrates, the activity of SRs allosterically depends on binding a hormonal ligand; in mollusks, however, the SR ortholog (called ER, because of high sequence similarity to vertebrate estrogen receptors activates transcription in the absence of ligand and does not respond to steroid hormones. To understand how this shift in regulation evolved, we combined evolutionary, structural, and functional analyses. We first determined the X-ray crystal structure of the ER of the Pacific oyster Crassostrea gigas (CgER, and found that its ligand pocket is filled with bulky residues that prevent ligand occupancy. To understand the genetic basis for the evolution of mollusk ERs' unique functions, we resurrected an ancient SR progenitor and characterized the effect of historical amino acid replacements on its functions. We found that reintroducing just two ancient replacements from the lineage leading to mollusk ERs recapitulates the evolution of full constitutive activity and the loss of ligand activation. These substitutions stabilize interactions among key helices, causing the allosteric switch to become "stuck" in the active conformation and making activation independent of ligand binding. Subsequent changes filled the ligand pocket without further affecting activity; by degrading the allosteric switch, these substitutions vestigialized elements of the protein's architecture required for ligand regulation and made reversal to the ancestral function more complex. These findings show how the physical architecture of allostery enabled a few large

Progress in switching technology for METS systems

International Nuclear Information System (INIS)

Honig, E.M.; Swannack, C.E.; Warren, R.W.; Whitaker, D.H.

1977-01-01

Three distinct sets of switching requirements have emerged from design optimization studies of large superconducting magnetic energy storage systems, such as the METS system to power the adiabatic plasma compression field in the proposed theta-pinch SFTR. Extremely low joule loss cryogenic disconnects are required between storage coils in the liquid helium environment to allow charging the coils in series over a prolonged time, then to isolate the coils for parallel fast discharging into the load. Another switch must break the current in the series charging loop and absorb the energy from the stray inductance. This action will allow the subsequent opening of the cryogenic disconnects under near zero current condition. The current now has been transferred to the many paralleled circuits, each containing a high current, high voltage interrupter. The opening and arc commutation of the interrupter starts the energy transfer into the load. The primary activities associated with cryogenic disconnect have been testing and development of contact materials, configurations, and closing forces for carrying 26 kA with a resistance less than 40 nΩ, and development of an actuating system that is both reliable and fast acting in a liquid helium environment. The charging loop switch will include a continuous duty switch and a vacuum interrupter. The continuous duty switch resistance can be an order of magnitude larger than that of the cryogenic disconnect because it does not present a refrigeration load. The HVDC interrupter must break 26 kA and withstand 60 kV during the energy transfer time of 700 μs. Testing in progress already has shown successful interruption using single vacuum interrupters up to 31 kA and 66 kV

Recent developments in switching theory

CERN Document Server

Mukhopadhyay, Amar

2013-01-01

Electrical Science Series: Recent Developments in Switching Theory covers the progress in the study of the switching theory. The book discusses the simplified proof of Post's theorem on completeness of logic primitives; the role of feedback in combinational switching circuits; and the systematic procedure for the design of Lupanov decoding networks. The text also describes the classical results on counting theorems and their application to the classification of switching functions under different notions of equivalence, including linear and affine equivalences. The development of abstract har

Amorphous metal based nanoelectromechanical switch

KAUST Repository

Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

2013-01-01

Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

Switched-capacitor isolated LED driver

Science.gov (United States)

Sanders, Seth R.; Kline, Mitchell

2016-03-22

A switched-capacitor voltage converter which is particularly well-suited for receiving a line voltage from which to drive current through a series of light emitting diodes (LEDs). Input voltage is rectified in a multi-level rectifier network having switched capacitors in an ascending-bank configuration for passing voltages in uniform steps between zero volts up to full received voltage V.sub.DC. A regulator section, operating on V.sub.DC, comprises switched-capacitor stages of H-bridge switching and flying capacitors. A current controlled oscillator drives the states of the switched-capacitor stages and changes its frequency to maintain a constant current to the load. Embodiments are described for isolating the load from the mains, utilizing an LC tank circuit or a multi-primary-winding transformer.

Amorphous metal based nanoelectromechanical switch

KAUST Repository

Mayet, Abdulilah M.

2013-04-01

Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

A Novel Four-Step Commutation for Bidirectional Switch Cells of AC-AC Matrix Converter

DEFF Research Database (Denmark)

Guo, Yougui; Zeng, Ping; Blaabjerg, Frede

2012-01-01

on or off of output current happens on the second and third steps. Here the second step is equal to the third one. This method is implemented with four steps by programming in VHDL language. First, the special flip-flop, 74AHC16373, is obtained by programming so as to make input sector signals, output...... sector ones and active switching time PWM ones synchronize. Second, the required switching states are flexibly realized in the form of the look-up table by programming in VHDL language for 36 switching combinations of input sectors with output ones. Third, the obtained switching states are judged whether...... they need commutation by delayers. Finally, the novel method proposed is implemented by switching sequencers. The simulation results have verified its feasibility....

Online co-regularized algorithms

NARCIS (Netherlands)

Ruijter, T. de; Tsivtsivadze, E.; Heskes, T.

2012-01-01

We propose an online co-regularized learning algorithm for classification and regression tasks. We demonstrate that by sequentially co-regularizing prediction functions on unlabeled data points, our algorithm provides improved performance in comparison to supervised methods on several UCI benchmarks

Geometric continuum regularization of quantum field theory

International Nuclear Information System (INIS)

Halpern, M.B.

1989-01-01

An overview of the continuum regularization program is given. The program is traced from its roots in stochastic quantization, with emphasis on the examples of regularized gauge theory, the regularized general nonlinear sigma model and regularized quantum gravity. In its coordinate-invariant form, the regularization is seen as entirely geometric: only the supermetric on field deformations is regularized, and the prescription provides universal nonperturbative invariant continuum regularization across all quantum field theory. 54 refs

Phospho switch triggers Brd4 chromatin binding and activator recruitment for gene-specific targeting.

Science.gov (United States)

Wu, Shwu-Yuan; Lee, A-Young; Lai, Hsien-Tsung; Zhang, Hong; Chiang, Cheng-Ming

2013-03-07

Bromodomain-containing protein 4 (Brd4) is an epigenetic reader and transcriptional regulator recently identified as a cancer therapeutic target for acute myeloid leukemia, multiple myeloma, and Burkitt's lymphoma. Although chromatin targeting is a crucial function of Brd4, there is little understanding of how bromodomains that bind acetylated histones are regulated, nor how the gene-specific activity of Brd4 is determined. Via interaction screen and domain mapping, we identified p53 as a functional partner of Brd4. Interestingly, Brd4 association with p53 is modulated by casein kinase II (CK2)-mediated phosphorylation of a conserved acidic region in Brd4 that selectively contacts either a juxtaposed bromodomain or an adjacent basic region to dictate the ability of Brd4 binding to chromatin and also the recruitment of p53 to regulated promoters. The unmasking of bromodomains and activator recruitment, concurrently triggered by the CK2 phospho switch, provide an intriguing mechanism for gene-specific targeting by a universal epigenetic reader. Copyright © 2013 Elsevier Inc. All rights reserved.

Micromagnetic analysis of geometrically controlled current-driven magnetization switching

Directory of Open Access Journals (Sweden)

O. Alejos

2017-05-01

Full Text Available The magnetization dynamics induced by current pulses in a pair of two “S-shaped” ferromagnetic elements, each one consisting on two oppositely tilted tapered spikes at the ends of a straight section, is theoretically studied by means of micromagnetic simulations. Our results indicate that the magnetization reversal is triggered by thermal activation, which assists the current-induced domain nucleation and the propagation of domain walls. The detailed analysis of the magnetization dynamics reveals that the magnetization switching is only achieved when a single domain wall is nucleated in the correct corner of the element. In agreement with recent experimental studies, the switching is purely dictated by the shape, being independent of the current polarity. The statistical study points out that successful switching is only achieved within a narrow range of the current pulse amplitudes.

Low temperature grown GaNAsSb: A promising material for photoconductive switch application

Energy Technology Data Exchange (ETDEWEB)

Tan, K. H.; Yoon, S. F.; Wicaksono, S.; Loke, W. K.; Li, D. S. [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Saadsaoud, N.; Tripon-Canseliet, C. [Laboratoire d' Electronique et Electromagnétisme, Pierre and Marie Curie University, 4 Place Jussieu, 75005 Paris (France); Lampin, J. F.; Decoster, D. [Institute of Electronics, Microelectronics and Nanotechnology (IEMN), UMR CNRS 8520, Universite des Sciences et Technologies de Lille, BP 60069, 59652 Villeneuve d' Ascq Cedex (France); Chazelas, J. [Thales Airborne Systems, 2 Avenue Gay Lussac, 78852 Elancourt (France)

2013-09-09

We report a photoconductive switch using low temperature grown GaNAsSb as the active material. The GaNAsSb layer was grown at 200 °C by molecular beam epitaxy in conjunction with a radio frequency plasma-assisted nitrogen source and a valved antimony cracker source. The low temperature growth of the GaNAsSb layer increased the dark resistivity of the switch and shortened the carrier lifetime. The switch exhibited a dark resistivity of 10{sup 7} Ω cm, a photo-absorption of up to 2.1 μm, and a carrier lifetime of ∼1.3 ps. These results strongly support the suitability of low temperature grown GaNAsSb in the photoconductive switch application.

Differential preparation intervals modulate repetition processes in task switching: an ERP study

Directory of Open Access Journals (Sweden)

Min eWang

2016-02-01

Full Text Available In task-switching paradigms, reaction times (RTs switch cost (SC and the neural correlates underlying the SC are affected by different preparation intervals. However, little is known about the effect of the preparation interval on the repetition processes in task-switching. To examine this effect we utilized a cued task-switching paradigm with long sequences of repeated trials. Response-stimulus intervals (RSI and cue-stimulus intervals (CSI were manipulated in short and long conditions. Electroencephalography (EEG and behavioral data were recorded. We found that with increasing repetitions, RTs were faster in the short CSI conditions, while P3 amplitudes decreased in the LS (long RSI and short CSI conditions. Positive correlations between RT benefit and P3 activation decrease (repeat 1 minus repeat 5, and between the slope of the RT and P3 regression lines were observed only in the LS condition. Our findings suggest that differential preparation intervals modulate repetition processes in task switching.

Bypassing the Limits of Ll Regularization: Convex Sparse Signal Processing Using Non-Convex Regularization

Science.gov (United States)

Parekh, Ankit

Sparsity has become the basis of some important signal processing methods over the last ten years. Many signal processing problems (e.g., denoising, deconvolution, non-linear component analysis) can be expressed as inverse problems. Sparsity is invoked through the formulation of an inverse problem with suitably designed regularization terms. The regularization terms alone encode sparsity into the problem formulation. Often, the ℓ1 norm is used to induce sparsity, so much so that ℓ1 regularization is considered to be `modern least-squares'. The use of ℓ1 norm, as a sparsity-inducing regularizer, leads to a convex optimization problem, which has several benefits: the absence of extraneous local minima, well developed theory of globally convergent algorithms, even for large-scale problems. Convex regularization via the ℓ1 norm, however, tends to under-estimate the non-zero values of sparse signals. In order to estimate the non-zero values more accurately, non-convex regularization is often favored over convex regularization. However, non-convex regularization generally leads to non-convex optimization, which suffers from numerous issues: convergence may be guaranteed to only a stationary point, problem specific parameters may be difficult to set, and the solution is sensitive to the initialization of the algorithm. The first part of this thesis is aimed toward combining the benefits of non-convex regularization and convex optimization to estimate sparse signals more effectively. To this end, we propose to use parameterized non-convex regularizers with designated non-convexity and provide a range for the non-convex parameter so as to ensure that the objective function is strictly convex. By ensuring convexity of the objective function (sum of data-fidelity and non-convex regularizer), we can make use of a wide variety of convex optimization algorithms to obtain the unique global minimum reliably. The second part of this thesis proposes a non-linear signal

DEVELOPMENT OF INNOVATION MANAGEMENT THEORY BASED ON SYSTEM-WIDE REGULARITIES

Directory of Open Access Journals (Sweden)

Violetta N. Volkova

2013-01-01

Full Text Available The problem of a comprehension of the innovation management theory and an ability of its development on basis of system theory is set up. The authors consider features of management of socio-economic systems as open, self-organising systems with active components and give a classification of the systems’ regularities illustrating these features. The need to take into account the regularities of emergent, hierarchical order, equifinality, Ashby’s law of requisite variety, historicity and self-organization is shown.

Call for Papers: Photonics in Switching

Science.gov (United States)

Wosinska, Lena; Glick, Madeleine

2006-04-01

Call for Papers: Photonics in Switching Guest Editors: Lena Wosinska, Royal Institute of Technology (KTH) / ICT Sweden Madeleine Glick, Intel Research, Cambridge, UK Technologies based on DWDM systems allow data transmission with bit rates of Tbit/s on a single fiber. To facilitate this enormous transmission volume, high-capacity and high-speed network nodes become inevitable in the optical network. Wideband switching, WDM switching, optical burst switching (OBS), and optical packet switching (OPS) are promising technologies for harnessing the bandwidth of WDM optical fiber networks in a highly flexible and efficient manner. As a number of key optical component technologies approach maturity, photonics in switching is becoming an increasingly attractive and practical solution for the next-generation of optical networks. The scope of this special issue is focused on the technology and architecture of optical switching nodes, including the architectural and algorithmic aspects of high-speed optical networks. Scope of Submission The scope of the papers includes, but is not limited to, the following topics: WDM node architectures Novel device technologies enabling photonics in switching, such as optical switch fabrics, optical memory, and wavelength conversion Routing protocols WDM switching and routing Quality of service Performance measurement and evaluation Next-generation optical networks: architecture, signaling, and control Traffic measurement and field trials Optical burst and packet switching OBS/OPS node architectures Burst/Packet scheduling and routing algorithms Contention resolution/avoidance strategies Services and applications for OBS/OPS (e.g., grid networks, storage-area networks, etc.) Burst assembly and ingress traffic shaping Hybrid OBS/TDM or OBS/wavelength routing Manuscript Submission To submit to this special issue, follow the normal procedure for submission to JON and select ``Photonics in Switching' in the features indicator of the online

Using Tikhonov Regularization for Spatial Projections from CSR Regularized Spherical Harmonic GRACE Solutions

Science.gov (United States)

Save, H.; Bettadpur, S. V.

2013-12-01

It has been demonstrated before that using Tikhonov regularization produces spherical harmonic solutions from GRACE that have very little residual stripes while capturing all the signal observed by GRACE within the noise level. This paper demonstrates a two-step process and uses Tikhonov regularization to remove the residual stripes in the CSR regularized spherical harmonic coefficients when computing the spatial projections. We discuss methods to produce mass anomaly grids that have no stripe features while satisfying the necessary condition of capturing all observed signal within the GRACE noise level.

Regularized maximum correntropy machine

KAUST Repository

Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

2015-01-01

In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

Regularized maximum correntropy machine

KAUST Repository

Wang, Jim Jing-Yan

2015-02-12

In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

The impact of the inclusion of students with handicaps and disabilities in the regular education science classroom

Science.gov (United States)

Donald, Cathey Nolan

This study was conducted to determine the impact of the inclusion of students with handicaps and disabilities in the regular education science classroom. Surveys were mailed to the members of the Alabama Science Teachers Association to obtain information from teachers in inclusive classrooms. Survey responses from teachers provide insight into these classrooms. This study reports the results of the teachers surveyed. Results indicate multiple changes occur in the educational opportunities presented to regular education students when students with handicaps and disabilities are included in the regular science classroom. Responding teachers (60%) report omitting activities that formerly provided experiences for students, such as laboratory activities using dangerous materials, field activities, and some group activities. Also omitted, in many instances (64.1%), are skill building opportunities of word problems and higher order thinking skills. Regular education students participate in classes where discipline problems related to included students are reported as the teachers most time consuming task. In these classrooms, directions are repeated frequently, reteaching of material already taught occurs, and the pace of instruction has been slowed. These changes to the regular classroom occur across school levels. Many teachers (44.9%) report they do not see benefits associated with the inclusion of students with special needs in the regular classroom.

Soft switching buck-boost converter for photovoltaic power generation; Taiyoko hatsuden no tame no soft switching shokoatsu converter

Energy Technology Data Exchange (ETDEWEB)

Lee, H. [Kyungnam University (Korea, Republic of)

1996-10-27

A soft switching method with small switching loss was proposed for the purpose of increasing the efficiency of a DC-DC boost converter which converted a DC current generated by solar cells to a variable DC current. Existing current converters are supplemented by using a snubber circuit around the switch so as to protect the switch by a hard switching action. However, with an increase of the output current, snubber loss is increased, reducing the efficiency. In order to solve this problem, the partial resonant switch method was applied to the converter; with this method of partially forming a resonant circuit only at the time of turning on/off of the switch, the switching loss was reduced through the soft switching, thereby making the proposed converter operate with high efficiency. Moreover, the resonant element of the partial resonant circuit using a snubber condenser, the energy accumulated in the condenser was regenerated on the power supply side without loss of snubber. With the regenerated energy, the proposed converter was provided with a smaller ratio of switching to use than the conventional converter. 4 refs., 7 figs., 1 tab.

Taste, a new incentive to switch to (R-praziquantel in schistosomiasis treatment.

Directory of Open Access Journals (Sweden)

Thorsten Meyer

Full Text Available BACKGROUND: Praziquantel (PZQ is the drug compound of choice in the control and treatment of schistosomiasis. PZQ is administered as a racemate, i. e. 1ratio1 mixture of enantiomers. The schistosomicidal activity arises from one PZQ-enantiomer, whereas the other enantiomer does not contribute to the activity. The WHO's Special Programme for Research and Training in Tropical Diseases (TDR has assigned the low-cost preparation of pure schistosomicidal (--PZQ a key priority for future R&D on PZQ, but so far this transition has not happened. PZQ has two major administration drawbacks, the first being the high dose needed, and its well documented bitter and disgusting taste. Attempts of taste-masking by low-cost means have not been successful. We hypothesized that the non-schistosomicidal component in PZQ would be the main contributor to the unpleasant taste of the drug. If the hypothesis was confirmed, the two major administration drawbacks of PZQ, the high dose needed and its bitter taste, could be addressed in one go by removing the component contributing to the bitter taste. METHODS AND FINDINGS: PZQ was separated into its schistosomicidal and the non-schistosomicidal component, the absolute stereochemical configuration of (--PZQ was determined to be (R-PZQ by X-ray crystallography, and the extent of bitterness was determined for regular racemic PZQ and the schistosomicidal component in a taste study in humans. FINDING: The schistosomicidal component alone is significantly less bitter than regular, racemic PZQ. CONCLUSION: Our hypothesis is confirmed. We propose to use only the pure schistosomicidal component of PZQ, offering the advantage of halving the dose and expectedly improving the compliance due to the removal of the bitter taste. Therefore, (R-PZQ should be specifically suitable for the treatment of school-age children against schistosomiasis. With this finding, we would like to offer an additional incentive to the TDR's recommendation to

Hypothalamic Leptin Gene Therapy Reduces Bone Marrow Adiposity in ob/ob Mice Fed Regular and High Fat Diets

Directory of Open Access Journals (Sweden)

Laurence B Lindenmaier

2016-08-01

Full Text Available Low bone mass is often associated with increased bone marrow adiposity. Since osteoblasts and adipocytes are derived from the same mesenchymal stem cell progenitor, adipocyte formation may increase at the expense of osteoblast formation. Leptin is an adipocyte-derived hormone known to regulate energy and bone metabolism. Genetic (e.g., leptin deficiency and high fat diet-induced (e.g., leptin resistance obesity are associated with increased marrow adipose tissue (MAT and reduced bone formation. Short-duration studies suggest that leptin treatment reduces MAT and increases bone formation in leptin-deficient ob/ob mice fed a regular diet. Here, we determined the long-duration impact of increased hypothalamic leptin on marrow adipocytes and osteoblasts in ob/ob mice using recombinant adeno-associated virus (rAAV gene therapy. In a first study, eight- to ten-week-old male ob/ob mice were randomized into 4 groups: (1 untreated, (2 rAAV-Lep, (3 rAAV-green fluorescent protein (rAAV-GFP, or (4 pair-fed to rAAV-Lep. For vector administration, mice were placed in a Kopf stereotaxic apparatus, and injected intracerebroventricularly with either rAAV-Lep or rAAV-GFP (9 × 107 particles in 1.5 µl. The mice were maintained for 30 weeks following vector administration. In a second study, the impact of increased hypothalamic leptin levels on MAT was determined in mice fed high fat diets. Eight- to ten-week-old male ob/ob mice were randomized into 2 groups and treated with either rAAV-Lep or rAAV-GFP. At 7 weeks post-vector administration, half the mice in each group were switched to a high fat diet for 8 weeks. Wild type (WT controls included age-matched mice fed regular or high fat diet. Hypothalamic leptin gene therapy increased osteoblast perimeter and osteoclast perimeter with minor change in cancellous bone architecture. The gene therapy decreased MAT levels in ob/ob mice fed regular or high fat diet to values similar to WT mice fed regular diet. These

Migration of interfacial oxygen ions modulated resistive switching in oxide-based memory devices

Science.gov (United States)

Chen, C.; Gao, S.; Zeng, F.; Tang, G. S.; Li, S. Z.; Song, C.; Fu, H. D.; Pan, F.

2013-07-01

Oxides-based resistive switching memory induced by oxygen ions migration is attractive for future nonvolatile memories. Numerous works had focused their attentions on the sandwiched oxide materials for depressing the characteristic variations, but the comprehensive studies of the dependence of electrodes on the migration behavior of oxygen ions are overshadowed. Here, we investigated the interaction of various metals (Ni, Co, Al, Ti, Zr, and Hf) with oxygen atoms at the metal/Ta2O5 interface under electric stress and explored the effect of top electrode on the characteristic variations of Ta2O5-based memory device. It is demonstrated that chemically inert electrodes (Ni and Co) lead to the scattering switching characteristics and destructive gas bubbles, while the highly chemically active metals (Hf and Zr) formed a thick and dense interfacial intermediate oxide layer at the metal/Ta2O5 interface, which also degraded the resistive switching behavior. The relatively chemically active metals (Al and Ti) can absorb oxygen ions from the Ta2O5 film and avoid forming the problematic interfacial layer, which is benefit to the formation of oxygen vacancies composed conduction filaments in Ta2O5 film thus exhibit the minimum variations of switching characteristics. The clarification of oxygen ions migration behavior at the interface can lead further optimization of resistive switching performance in Ta2O5-based memory device and guide the rule of electrode selection for other oxide-based resistive switching memories.

Harmonic Analysis and Mitigation of Low- Frequency Switching Voltage Source Inverter with Auxiliary VSI

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

2018-01-01

The output currents of high-power Voltage Source Inverters (VSIs) are distorted by the switching harmonics and the background harmonics in the grid voltage. This paper presents an active harmonic filtering scheme for high-power, low-frequency switching VSIs with an additional auxiliary VSI. In th...

Non-fragile switched H∞ control for morphing aircraft with asynchronous switching

Directory of Open Access Journals (Sweden)

Haoyu CHENG

2017-06-01

Full Text Available This paper deals with the problem of non-fragile linear parameter-varying (LPV H∞ control for morphing aircraft with asynchronous switching. The switched LPV model of morphing aircraft is established by Jacobian linearization approach according to the nonlinear model. The data missing is taken into account in the link from sensors to controllers and the link from controllers to actuators, which satisfies Bernoulli distribution. The non-fragile switched LPV controllers are constructed with consideration of the uncertainties of controllers and asynchronous switching phenomenon. The parameter-dependent Lyapunov functional method and mode-dependent average dwell time (MDADT method are combined to guarantee the stability and prescribed performance of the system. The sufficient conditions on the solvability of the problem are derived in the form of linear matrix inequalities (LMI. In order to achieve higher efficiency of the designing process, an algorithm is applied to divide the whole set into subsets automatically. Simulation results are provided to verify the effectiveness and superiority of the method in the paper.

Streamer model for high voltage water switches

International Nuclear Information System (INIS)

Sazama, F.J.; Kenyon, V.L. III

1979-01-01

An electrical switch model for high voltage water switches has been developed which predicts streamer-switching effects that correlate well with water-switch data from Casino over the past four years and with switch data from recent Aurora/AMP experiments. Preclosure rounding and postclosure resistive damping of pulseforming line voltage waveforms are explained in terms of spatially-extensive, capacitive-coupling of the conducting streamers as they propagate across the gap and in terms of time-dependent streamer resistance and inductance. The arc resistance of the Casino water switch and of a gas switch under test on Casino was determined by computer fit to be 0.5 +- 0.1 ohms and 0.3 +- 0.06 ohms respectively, during the time of peak current in the power pulse. Energy lost in the water switch during the first pulse is 18% of that stored in the pulseforming line while similar energy lost in the gas switch is 11%. The model is described, computer transient analyses are compared with observed water and gas switch data and the results - switch resistance, inductance and energy loss during the primary power pulse - are presented

Development of the switching components for ZT-40

International Nuclear Information System (INIS)

Melton, J.G.; Dike, R.S.; Hanks, K.W.; Nunnally, W.C.

1977-01-01

Switching of the main capacitor banks for ZT-40 will be accomplished by spark gap switches. Initially, there will be 576 start switches and 288 crowbar switches. A development program is under way to develop three switches; (1) a versatile start switch, which can be used for both the I/sub z/ and the I/sub theta/ capacitor banks, with a wide operating voltage range, (2) a crowbar switch which is capable of crowbarring the circuit without the power crowbar bank, and (3) a power crowbar switch, which can handle 50 to 100 coulombs, so that a large number of crowbar switches will not be required when the power crowbar circuit is added. The problems with the start switches and the first crowbar switch have been solved, or alleviated. The development of a power crowbar switch has just begun

Switch mode power supply

International Nuclear Information System (INIS)

Kim, Hui Jun

1993-06-01

This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

Regular group exercise contributes to balanced health in older adults in Japan: a qualitative study.

Science.gov (United States)

Komatsu, Hiroko; Yagasaki, Kaori; Saito, Yoshinobu; Oguma, Yuko

2017-08-22

While community-wide interventions to promote physical activity have been encouraged in older adults, evidence of their effectiveness remains limited. We conducted a qualitative study among older adults participating in regular group exercise to understand their perceptions of the physical, mental, and social changes they underwent as a result of the physical activity. We conducted a qualitative study with purposeful sampling to explore the experiences of older adults who participated in regular group exercise as part of a community-wide physical activity intervention. Four focus group interviews were conducted between April and June of 2016 at community halls in Fujisawa City. The participants in the focus group interviews were 26 older adults with a mean age of 74.69 years (range: 66-86). The interviews were analysed using the constant comparative method in the grounded theory approach. We used qualitative research software NVivo10® to track the coding and manage the data. The finding 'regular group exercise contributes to balanced health in older adults' emerged as an overarching theme with seven categories (regular group exercise, functional health, active mind, enjoyment, social connectedness, mutual support, and expanding communities). Although the participants perceived that they were aging physically and cognitively, the regular group exercise helped them to improve or maintain their functional health and enjoy their lives. They felt socially connected and experienced a sense of security in the community through caring for others and supporting each other. As the older adults began to seek value beyond individuals, they gradually expanded their communities beyond geographical and generational boundaries. The participants achieved balanced health in the physical, mental, and social domains through regular group exercise as part of a community-wide physical activity intervention and contributed to expanding communities through social connectedness and

LMI-based adaptive reliable H∞ static output feedback control against switched actuator failures

Science.gov (United States)

An, Liwei; Zhai, Ding; Dong, Jiuxiang; Zhang, Qingling

2017-08-01

This paper investigates the H∞ static output feedback (SOF) control problem for switched linear system under arbitrary switching, where the actuator failure models are considered to depend on switching signal. An active reliable control scheme is developed by combination of linear matrix inequality (LMI) method and adaptive mechanism. First, by exploiting variable substitution and Finsler's lemma, new LMI conditions are given for designing the SOF controller. Compared to the existing results, the proposed design conditions are more relaxed and can be applied to a wider class of no-fault linear systems. Then a novel adaptive mechanism is established, where the inverses of switched failure scaling factors are estimated online to accommodate the effects of actuator failure on systems. Two main difficulties arise: first is how to design the switched adaptive laws to prevent the missing of estimating information due to switching; second is how to construct a common Lyapunov function based on a switched estimate error term. It is shown that the new method can give less conservative results than that for the traditional control design with fixed gain matrices. Finally, simulation results on the HiMAT aircraft are given to show the effectiveness of the proposed approaches.

Regularity and predictability of human mobility in personal space.

Directory of Open Access Journals (Sweden)

Daniel Austin

Full Text Available Fundamental laws governing human mobility have many important applications such as forecasting and controlling epidemics or optimizing transportation systems. These mobility patterns, studied in the context of out of home activity during travel or social interactions with observations recorded from cell phone use or diffusion of money, suggest that in extra-personal space humans follow a high degree of temporal and spatial regularity - most often in the form of time-independent universal scaling laws. Here we show that mobility patterns of older individuals in their home also show a high degree of predictability and regularity, although in a different way than has been reported for out-of-home mobility. Studying a data set of almost 15 million observations from 19 adults spanning up to 5 years of unobtrusive longitudinal home activity monitoring, we find that in-home mobility is not well represented by a universal scaling law, but that significant structure (predictability and regularity is uncovered when explicitly accounting for contextual data in a model of in-home mobility. These results suggest that human mobility in personal space is highly stereotyped, and that monitoring discontinuities in routine room-level mobility patterns may provide an opportunity to predict individual human health and functional status or detect adverse events and trends.

Purification of reversibly oxidized proteins (PROP reveals a redox switch controlling p38 MAP kinase activity.

Directory of Open Access Journals (Sweden)

Dennis J Templeton

2010-11-01

Full Text Available Oxidation of cysteine residues of proteins is emerging as an important means of regulation of signal transduction, particularly of protein kinase function. Tools to detect and quantify cysteine oxidation of proteins have been a limiting factor in understanding the role of cysteine oxidation in signal transduction. As an example, the p38 MAP kinase is activated by several stress-related stimuli that are often accompanied by in vitro generation of hydrogen peroxide. We noted that hydrogen peroxide inhibited p38 activity despite paradoxically increasing the activating phosphorylation of p38. To address the possibility that cysteine oxidation may provide a negative regulatory effect on p38 activity, we developed a biochemical assay to detect reversible cysteine oxidation in intact cells. This procedure, PROP, demonstrated in vivo oxidation of p38 in response to hydrogen peroxide and also to the natural inflammatory lipid prostaglandin J2. Mutagenesis of the potential target cysteines showed that oxidation occurred preferentially on residues near the surface of the p38 molecule. Cysteine oxidation thus controls a functional redox switch regulating the intensity or duration of p38 activity that would not be revealed by immunodetection of phosphoprotein commonly interpreted as reflective of p38 activity.

Chromatic interocular-switch rivalry.

Science.gov (United States)

Christiansen, Jens H; D'Antona, Anthony D; Shevell, Steven K

2017-05-01

Interocular-switch rivalry (also known as stimulus rivalry) is a kind of binocular rivalry in which two rivalrous images are swapped between the eyes several times a second. The result is stable periods of one image and then the other, with stable intervals that span many eye swaps (Logothetis, Leopold, & Sheinberg, 1996). Previous work used this close kin of binocular rivalry with rivalrous forms. Experiments here test whether chromatic interocular-switch rivalry, in which the swapped stimuli differ in only chromaticity, results in slow alternation between two colors. Swapping equiluminant rivalrous chromaticities at 3.75 Hz resulted in slow perceptual color alternation, with one or the other color often continuously visible for two seconds or longer (during which there were 15+ eye swaps). A well-known theory for sustained percepts from interocular-switch rivalry with form is inhibitory competition between binocular neurons driven by monocular neurons with matched orientation tuning in each eye; such binocular neurons would produce a stable response when a given orientation is swapped between the eyes. A similar model can account for the percepts here from chromatic interocular-switch rivalry and is underpinned by the neurophysiological finding that color-preferring binocular neurons are driven by monocular neurons from each eye with well-matched chromatic selectivity (Peirce, Solomon, Forte, & Lennie, 2008). In contrast to chromatic interocular-switch rivalry, luminance interocular-switch rivalry with swapped stimuli that differ in only luminance did not result in slowly alternating percepts of different brightnesses.

Borderline personality disorder and regularly drinking alcohol before sex.

Science.gov (United States)

Thompson, Ronald G; Eaton, Nicholas R; Hu, Mei-Chen; Hasin, Deborah S

2017-07-01

Drinking alcohol before sex increases the likelihood of engaging in unprotected intercourse, having multiple sexual partners and becoming infected with sexually transmitted infections. Borderline personality disorder (BPD), a complex psychiatric disorder characterised by pervasive instability in emotional regulation, self-image, interpersonal relationships and impulse control, is associated with substance use disorders and sexual risk behaviours. However, no study has examined the relationship between BPD and drinking alcohol before sex in the USA. This study examined the association between BPD and regularly drinking before sex in a nationally representative adult sample. Participants were 17 491 sexually active drinkers from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Logistic regression models estimated effects of BPD diagnosis, specific borderline diagnostic criteria and BPD criterion count on the likelihood of regularly (mostly or always) drinking alcohol before sex, adjusted for controls. Borderline personality disorder diagnosis doubled the odds of regularly drinking before sex [adjusted odds ratio (AOR) = 2.26; confidence interval (CI) = 1.63, 3.14]. Of nine diagnostic criteria, impulsivity in areas that are self-damaging remained a significant predictor of regularly drinking before sex (AOR = 1.82; CI = 1.42, 2.35). The odds of regularly drinking before sex increased by 20% for each endorsed criterion (AOR = 1.20; CI = 1.14, 1.27) DISCUSSION AND CONCLUSIONS: This is the first study to examine the relationship between BPD and regularly drinking alcohol before sex in the USA. Substance misuse treatment should assess regularly drinking before sex, particularly among patients with BPD, and BPD treatment should assess risk at the intersection of impulsivity, sexual behaviour and substance use. [Thompson Jr RG, Eaton NR, Hu M-C, Hasin DS Borderline personality disorder and regularly drinking alcohol

Optimization of multi-branch switched diversity systems

KAUST Repository

Nam, Haewoon; Alouini, Mohamed-Slim

2009-01-01

A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold

A low-latency optical switch architecture using integrated μm SOI-based contention resolution and switching

Science.gov (United States)

Mourgias-Alexandris, G.; Moralis-Pegios, M.; Terzenidis, N.; Cherchi, M.; Harjanne, M.; Aalto, T.; Vyrsokinos, K.; Pleros, N.

2018-02-01

The urgent need for high-bandwidth and high-port connectivity in Data Centers has boosted the deployment of optoelectronic packet switches towards bringing high data-rate optics closer to the ASIC, realizing optical transceiver functions directly at the ASIC package for high-rate, low-energy and low-latency interconnects. Even though optics can offer a broad range of low-energy integrated switch fabrics for replacing electronic switches and seamlessly interface with the optical I/Os, the use of energy- and latency-consuming electronic SerDes continues to be a necessity, mainly dictated by the absence of integrated and reliable optical buffering solutions. SerDes undertakes the role of optimally synergizing the lower-speed electronic buffers with the incoming and outgoing optical streams, suggesting that a SerDes-released chip-scale optical switch fabric can be only realized in case all necessary functions including contention resolution and switching can be implemented on a common photonic integration platform. In this paper, we demonstrate experimentally a hybrid Broadcast-and-Select (BS) / wavelength routed optical switch that performs both the optical buffering and switching functions with μm-scale Silicon-integrated building blocks. Optical buffering is carried out in a silicon-integrated variable delay line bank with a record-high on-chip delay/footprint efficiency of 2.6ns/mm2 and up to 17.2 nsec delay capability, while switching is executed via a BS design and a silicon-integrated echelle grating, assisted by SOA-MZI wavelength conversion stages and controlled by a FPGA header processing module. The switch has been experimentally validated in a 3x3 arrangement with 10Gb/s NRZ optical data packets, demonstrating error-free switching operation with a power penalty of <5dB.

Polyaniline-based memristive microdevice with high switching rate and endurance

Science.gov (United States)

Lapkin, D. A.; Emelyanov, A. V.; Demin, V. A.; Erokhin, V. V.; Feigin, L. A.; Kashkarov, P. K.; Kovalchuk, M. V.

2018-01-01

Polyaniline (PANI) based memristive devices have emerged as promising candidates for hardware implementation of artificial synapses (the key components of neuromorphic systems) due to their high flexibility, low cost, solution processability, three-dimensional stacking capability, and biocompatibility. Here, we report on a way of the significant improvement of the switching rate and endurance of PANI-based memristive devices. The reduction of the PANI active channel dimension leads to the increase in the resistive switching rate by hundreds of times in comparison with the conventional one. The miniaturized memristive device was shown to be stable within at least 104 cyclic switching events between high- and low-conductive states with a retention time of at least 103 s. The obtained results make PANI-based memristive devices potentially widely applicable in neuromorphic systems.

Untriggered water switching

International Nuclear Information System (INIS)

Van Devender, J.P.; Martin, T.H.

Recent experiments indicate that synchronous untriggered multichannel switching in water will permit the development of relatively simple, ultra-low impedance, short pulse, relativistic electron beam (REB) accelerators. These experiments resulted in the delivery of a 1.5 MV, 0.75 MA, 15 ns pulse into a two-ohm line with a current risetime of 2 x 10 14 A/sec. The apparatus consisted of a 3 MV Marx generator and a series of three 112 cm wide strip water lines separated by two edge-plane water-gap switches. The Marx generator charged the first line in less than 400 ns. The first switch then formed five or more channels. The second line was charged in 60 ns and broke down with 10 to 25 channels at a mean field of 1.6 MV/cm. The closure time of each spark channel along both switches was measured with a streak camera and showed low jitter. The resulting fast pulse line construction is simpler and should provide considerable costs savings from previous designs. Multiples of these low impedance lines in parallel can be employed to obtain power levels in the 10 14 W range for REB fusion studies. (U.S.)

A network-flow based valve-switching aware binding algorithm for flow-based microfluidic biochips

DEFF Research Database (Denmark)

Tseng, Kai-Han; You, Sheng-Chi; Minhass, Wajid Hassan

2013-01-01

-flow based resource binding algorithm based on breadth-first search (BFS) and minimum cost maximum flow (MCMF) in architectural-level synthesis. The experimental results show that our methodology not only makes significant reduction of valve-switching activities but also diminishes the application completion......Designs of flow-based microfluidic biochips are receiving much attention recently because they replace conventional biological automation paradigm and are able to integrate different biochemical analysis functions on a chip. However, as the design complexity increases, a flow-based microfluidic...... biochip needs more chip-integrated micro-valves, i.e., the basic unit of fluid-handling functionality, to manipulate the fluid flow for biochemical applications. Moreover, frequent switching of micro-valves results in decreased reliability. To minimize the valve-switching activities, we develop a network...

Regularities of Multifractal Measures

Indian Academy of Sciences (India)

First, we prove the decomposition theorem for the regularities of multifractal Hausdorff measure and packing measure in R R d . This decomposition theorem enables us to split a set into regular and irregular parts, so that we can analyze each separately, and recombine them without affecting density properties. Next, we ...

Impact of the removal of light and mild descriptors from cigarette packages in Ontario, Canada: switching to "light replacement" brand variants.

Science.gov (United States)

Cohen, Joanna E; Yang, Jingyan; Donaldson, Elisabeth A

2014-12-01

This study assessed cessation and brand switching among smokers in Ontario, Canada after tobacco companies' voluntary removal of 'light' and 'mild' descriptors from cigarette packages. We analyzed longitudinal data on brand preference and cessation from a cohort of smokers (n=632) in the Ontario Tobacco Survey in Canada from 2006 to 2008 with a longitudinal regression model. While cessation differed by brand variant prior to the ban (7% light vs. 3% regular; Pbrand variant after the ban was implemented. In 2008, when light cigarette brand variants were no longer available, 33% of the sample still reported smoking lights and 31% smoked light replacement brand variants. During each subsequent follow-up, light brand smokers had 2 times the odds of smoking regular brand variants (Adjusted OR: 2.03, 95% CI 1.80,2.29), and almost 5 times the odds of using light replacement brand variants (Adjusted OR: 4.87, 95% CI 4.07,5.84), respectively, compared to continuing to smoke lights. Even after removing misleading descriptors from cigarette packs, smokers continued to report using light brand variants, and many switched to newly introduced light replacement brand variants. After full implementation of the ban, cessation did not vary by brand variant. Copyright © 2014. Published by Elsevier Inc.

A level switch with a sound tube

OpenAIRE

赤池, 誠規

2017-01-01

Level switches are sensor with an electrical contact output at a specific liquid, powder or bulk level. Most of traditional level switches are not suitable for harsh environments. The level switch in this study connects a loudspeaker on top end of the sound tube. When liquid, powder or bulk closes bottom end of the sound tube, the level switch turns on. The level switch is suitable for harsh environments and easy to install. The aim of this study is to propose a level switch with a sound tube...

A pH Switch Regulates the Inverse Relationship between Membranolytic and Chaperone-like Activities of HSP-1/2, a Major Protein of Horse Seminal Plasma.

Science.gov (United States)

Kumar, C Sudheer; Swamy, Musti J

2016-07-05

HSP-1/2, a major protein of horse seminal plasma binds to choline phospholipids present on the sperm plasma membrane and perturbs its structure by intercalating into the hydrophobic core, which results in an efflux of choline phospholipids and cholesterol, an important event in sperm capacitation. HSP-1/2 also exhibits chaperone-like activity (CLA) in vitro and protects target proteins against various kinds of stress. In the present study we show that HSP-1/2 exhibits destabilizing activity toward model supported and cell membranes. The membranolytic activity of HSP-1/2 is found to be pH dependent, with lytic activity being high at mildly acidic pH (6.0-6.5) and low at mildly basic pH (8.0-8.5). Interestingly, the CLA is also found to be pH dependent, with high activity at mildly basic pH and low activity at mildly acidic pH. Taken together the present studies demonstrate that the membranolytic and chaperone-like activities of HSP-1/2 have an inverse relationship and are regulated via a pH switch, which is reversible. The higher CLA observed at mildly basic pH could be correlated to an increase in surface hydrophobicity of the protein. To the best of our knowledge, this is the first study reporting regulation of two different activities of a chaperone protein by a pH switch.

Adaptive Regularization of Neural Classifiers

DEFF Research Database (Denmark)

Andersen, Lars Nonboe; Larsen, Jan; Hansen, Lars Kai

1997-01-01

We present a regularization scheme which iteratively adapts the regularization parameters by minimizing the validation error. It is suggested to use the adaptive regularization scheme in conjunction with optimal brain damage pruning to optimize the architecture and to avoid overfitting. Furthermo......, we propose an improved neural classification architecture eliminating an inherent redundancy in the widely used SoftMax classification network. Numerical results demonstrate the viability of the method...

Granzyme B-dependent proteolysis acts as a switch to enhance the proinflammatory activity of IL-1α.

LENUS (Irish Health Repository)

Afonina, Inna S

2011-10-21

Granzyme B is a cytotoxic lymphocyte-derived protease that plays a central role in promoting apoptosis of virus-infected target cells, through direct proteolysis and activation of constituents of the cell death machinery. However, previous studies have also implicated granzymes A and B in the production of proinflammatory cytokines, via a mechanism that remains undefined. Here we show that IL-1α is a substrate for granzyme B and that proteolysis potently enhanced the biological activity of this cytokine in vitro as well as in vivo. Consistent with this, compared with full-length IL-1α, granzyme B-processed IL-1α exhibited more potent activity as an immunoadjuvant in vivo. Furthermore, proteolysis of IL-1α within the same region, by proteases such as calpain and elastase, was also found to enhance its biological potency. Thus, IL-1α processing by multiple immune-related proteases, including granzyme B, acts as a switch to enhance the proinflammatory properties of this cytokine.

Calcium is the switch in the moonlighting dual function of the ligand-activated receptor kinase phytosulfokine receptor 1

KAUST Repository

Muleya, Victor

2014-09-23

Background: A number of receptor kinases contain guanylate cyclase (GC) catalytic centres encapsulated in the cytosolic kinase domain. A prototypical example is the phytosulfokine receptor 1 (PSKR1) that is involved in regulating growth responses in plants. PSKR1 contains both kinase and GC activities however the underlying mechanisms regulating the dual functions have remained elusive. Findings: Here, we confirm the dual activity of the cytoplasmic domain of the PSKR1 receptor. We show that mutations within the guanylate cyclase centre modulate the GC activity while not affecting the kinase catalytic activity. Using physiologically relevant Ca2+ levels, we demonstrate that its GC activity is enhanced over two-fold by Ca2+ in a concentration-dependent manner. Conversely, increasing Ca2+ levels inhibits kinase activity up to 500-fold at 100 nM Ca2+. Conclusions: Changes in calcium at physiological levels can regulate the kinase and GC activities of PSKR1. We therefore propose a functional model of how calcium acts as a bimodal switch between kinase and GC activity in PSKR1 that could be relevant to other members of this novel class of ligand-activated receptor kinases.

Superconductivity, energy storage and switching

International Nuclear Information System (INIS)

Laquer, H.L.

1974-01-01

The phenomenon of superconductivity can contribute to the technology of energy storage and switching in two distinct ways. On one hand the zero resistivity of the superconductor can produce essentially infinite time constants so that an inductive storage system can be charged from very low power sources. On the other hand, the recovery of finite resistivity in a normal-going superconducting switch can take place in extremely short times, so that a system can be made to deliver energy at a very high power level. Topics reviewed include: physics of superconductivity, limits to switching speed of superconductors, physical and engineering properties of superconducting materials and assemblies, switching methods, load impedance considerations, refrigeration economics, limitations imposed by present day and near term technology, performance of existing and planned energy storage systems, and a comparison with some alternative methods of storing and switching energy. (U.S.)

Polio endgame: the global switch from tOPV to bOPV.

Science.gov (United States)

Garon, Julie; Seib, Katherine; Orenstein, Walter A; Ramirez Gonzalez, Alejandro; Chang Blanc, Diana; Zaffran, Michel; Patel, Manish

2016-06-01

Globally, polio cases have reached an all-time low, and type 2 poliovirus (one of three) is eradicated. Oral polio vaccine (OPV) has been the primary tool, however, in rare cases, OPV induces paralysis. In 2013, the World Health Assembly endorsed the phased withdrawal of OPV and introduction of inactivated poliovirus vaccine (IPV) into childhood routine immunization schedules. Type 2 OPV will be withdrawn through a globally synchronized "switch" from trivalent OPV (all three types) to bivalent OPV (types 1 and 3). The switch will happen in 155 OPV-using countries between April 17(th) and May 1(st), 2016. Planned activities to reduce type 2 outbreak risks post-switch include the following: tOPV campaigns to increase type 2 immunity prior to the switch, monovalent OPV2 stockpiling to respond to outbreaks should they occur, containment of both wild and vaccine type 2 viruses, enhanced acute flaccid paralysis (AFP) and environmental surveillance, outbreak response protocols, and ensured access to IPV and bivalent OPV.

On the asymptotic stability of nonlinear mechanical switched systems

Science.gov (United States)

Platonov, A. V.

2018-05-01

Some classes of switched mechanical systems with dissipative and potential forces are considered. The case, where either dissipative or potential forces are essentially nonlinear, is studied. It is assumed that the zero equilibrium position of the system is asymptotically stable at least for one operating mode. We will look for sufficient conditions which guarantee the preservation of asymptotic stability of the equilibrium position under the switching of modes. The Lyapunov direct method is used. A Lyapunov function for considered system is constructed, which satisfies the differential inequality of special form for every operating mode. This inequality is nonlinear for the chosen mode with asymptotically stable equilibrium position, and it is linear for the rest modes. The correlations between the intervals of activity of the pointed mode and the intervals of activity of the rest modes are obtained which guarantee the required properties.

Differential Activation of Fast-Spiking and Regular-Firing Neuron Populations During Movement and Reward in the Dorsal Medial Frontal Cortex

Science.gov (United States)

Insel, Nathan; Barnes, Carol A.

2015-01-01

The medial prefrontal cortex is thought to be important for guiding behavior according to an animal's expectations. Efforts to decode the region have focused not only on the question of what information it computes, but also how distinct circuit components become engaged during behavior. We find that the activity of regular-firing, putative projection neurons contains rich information about behavioral context and firing fields cluster around reward sites, while activity among putative inhibitory and fast-spiking neurons is most associated with movement and accompanying sensory stimulation. These dissociations were observed even between adjacent neurons with apparently reciprocal, inhibitory–excitatory connections. A smaller population of projection neurons with burst-firing patterns did not show clustered firing fields around rewards; these neurons, although heterogeneous, were generally less selective for behavioral context than regular-firing cells. The data suggest a network that tracks an animal's behavioral situation while, at the same time, regulating excitation levels to emphasize high valued positions. In this scenario, the function of fast-spiking inhibitory neurons is to constrain network output relative to incoming sensory flow. This scheme could serve as a bridge between abstract sensorimotor information and single-dimensional codes for value, providing a neural framework to generate expectations from behavioral state. PMID:24700585

Condition Number Regularized Covariance Estimation.

Science.gov (United States)

Won, Joong-Ho; Lim, Johan; Kim, Seung-Jean; Rajaratnam, Bala

2013-06-01

Estimation of high-dimensional covariance matrices is known to be a difficult problem, has many applications, and is of current interest to the larger statistics community. In many applications including so-called the "large p small n " setting, the estimate of the covariance matrix is required to be not only invertible, but also well-conditioned. Although many regularization schemes attempt to do this, none of them address the ill-conditioning problem directly. In this paper, we propose a maximum likelihood approach, with the direct goal of obtaining a well-conditioned estimator. No sparsity assumption on either the covariance matrix or its inverse are are imposed, thus making our procedure more widely applicable. We demonstrate that the proposed regularization scheme is computationally efficient, yields a type of Steinian shrinkage estimator, and has a natural Bayesian interpretation. We investigate the theoretical properties of the regularized covariance estimator comprehensively, including its regularization path, and proceed to develop an approach that adaptively determines the level of regularization that is required. Finally, we demonstrate the performance of the regularized estimator in decision-theoretic comparisons and in the financial portfolio optimization setting. The proposed approach has desirable properties, and can serve as a competitive procedure, especially when the sample size is small and when a well-conditioned estimator is required.

Obligatory participation of macrophages in an angiopoietin 2-mediated cell death switch

OpenAIRE

Rao, Sujata; Lobov, Ivan B.; Vallance, Jefferson E.; Tsujikawa, Kaoru; Shiojima, Ichiro; Akunuru, Shailaja; Walsh, Kenneth; Benjamin, Laura E.; Lang, Richard A.

2007-01-01

Macrophages have a critical function in the recognition and engulfment of dead cells. In some settings, macrophages also actively signal programmed cell death. Here we show that during developmentally scheduled vascular regression, resident macrophages are an obligatory participant in a signaling switch that favors death over survival. This switch occurs when the signaling ligand angiopoietin 2 has the dual effect of suppressing survival signaling in vascular endothelial cells (VECs) and stim...

Optical Multidimensional Switching for Data Center Networks

DEFF Research Database (Denmark)

Kamchevska, Valerija

2017-01-01

. Software controlled switching using an on-chip integrated fiber switch is demonstrated and enabling of additional network functionalities such as multicast and optical grooming is experimentally confirmed. Altogether this work demonstrates the potential of optical switching technologies...... for the purpose of deploying optical switching within the network. First, the Hi-Ring data center architecture is proposed. It is based on optical multidimensional switching nodes that provide switching in hierarchically layered space, wavelength and time domain. The performance of the Hi-Ring architecture...... is evaluated experimentally and successful switching of both high capacity wavelength connections and time-shared subwavelengthconnections is demonstrated. Error-free performance is also achieved when transmitting 7 Tbit/s using multicore fiber, confirming the ability to scale the network. Moreover...

Pinning Synchronization of Switched Complex Dynamical Networks

Directory of Open Access Journals (Sweden)

Liming Du

2015-01-01

Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

From inactive to regular jogger

DEFF Research Database (Denmark)

Lund-Cramer, Pernille; Brinkmann Løite, Vibeke; Bredahl, Thomas Viskum Gjelstrup

study was conducted using individual semi-structured interviews on how a successful long-term behavior change had been achieved. Ten informants were purposely selected from participants in the DANO-RUN research project (7 men, 3 women, average age 41.5). Interviews were performed on the basis of Theory...... of Planned Behavior (TPB) and The Transtheoretical Model (TTM). Coding and analysis of interviews were performed using NVivo 10 software. Results TPB: During the behavior change process, the intention to jogging shifted from a focus on weight loss and improved fitness to both physical health, psychological......Title From inactive to regular jogger - a qualitative study of achieved behavioral change among recreational joggers Authors Pernille Lund-Cramer & Vibeke Brinkmann Løite Purpose Despite extensive knowledge of barriers to physical activity, most interventions promoting physical activity have proven...

Participation in regular leisure-time physical activity among individuals with type 2 diabetes not meeting Canadian guidelines: the influence of intention, perceived behavioral control, and moral norm.

Science.gov (United States)

Boudreau, François; Godin, Gaston

2014-12-01

Most people with type 2 diabetes do not engage in regular leisure-time physical activity. The theory of planned behavior and moral norm construct can enhance our understanding of physical activity intention and behavior among this population. This study aims to identify the determinants of both intention and behavior to participate in regular leisure-time physical activity among individuals with type 2 diabetes who not meet Canada's physical activity guidelines. By using secondary data analysis of a randomized computer-tailored print-based intervention, participants (n = 200) from the province of Quebec (Canada) completed and returned a baseline questionnaire measuring their attitude, perceived behavioral control, and moral norm. One month later, they self-reported their level of leisure-time physical activity. A hierarchical regression equation showed that attitude (beta = 0.10, P norm (beta = 0.45, P norm on behavior was mediated by intention and perceived behavioral control. The determinants investigated offered an excellent starting point for designing appropriate counseling messages to promote leisure-time physical activity among individuals with type 2 diabetes.

Efficient all-optical switching using slow light within a hollow fiber

DEFF Research Database (Denmark)

Bajcsy, Michal; Hofferberth, S.; Balic, Vlatko

2009-01-01

We demonstrate a fiber-optical switch that is activated at tiny energies corresponding to a few hundred optical photons per pulse. This is achieved by simultaneously confining both photons and a small laser-cooled ensemble of atoms inside the microscopic hollow core of a single-mode photonic-crys......-crystal fiber and using quantum optical techniques for generating slow light propagation and large nonlinear interaction between light beams.......We demonstrate a fiber-optical switch that is activated at tiny energies corresponding to a few hundred optical photons per pulse. This is achieved by simultaneously confining both photons and a small laser-cooled ensemble of atoms inside the microscopic hollow core of a single-mode photonic...

The neural substrates of impaired finger tapping regularity after stroke.

Science.gov (United States)

Calautti, Cinzia; Jones, P Simon; Guincestre, Jean-Yves; Naccarato, Marcello; Sharma, Nikhil; Day, Diana J; Carpenter, T Adrian; Warburton, Elizabeth A; Baron, Jean-Claude

2010-03-01

Not only finger tapping speed, but also tapping regularity can be impaired after stroke, contributing to reduced dexterity. The neural substrates of impaired tapping regularity after stroke are unknown. Previous work suggests damage to the dorsal premotor cortex (PMd) and prefrontal cortex (PFCx) affects externally-cued hand movement. We tested the hypothesis that these two areas are involved in impaired post-stroke tapping regularity. In 19 right-handed patients (15 men/4 women; age 45-80 years; purely subcortical in 16) partially to fully recovered from hemiparetic stroke, tri-axial accelerometric quantitative assessment of tapping regularity and BOLD fMRI were obtained during fixed-rate auditory-cued index-thumb tapping, in a single session 10-230 days after stroke. A strong random-effect correlation between tapping regularity index and fMRI signal was found in contralesional PMd such that the worse the regularity the stronger the activation. A significant correlation in the opposite direction was also present within contralesional PFCx. Both correlations were maintained if maximal index tapping speed, degree of paresis and time since stroke were added as potential confounds. Thus, the contralesional PMd and PFCx appear to be involved in the impaired ability of stroke patients to fingertap in pace with external cues. The findings for PMd are consistent with repetitive TMS investigations in stroke suggesting a role for this area in affected-hand movement timing. The inverse relationship with tapping regularity observed for the PFCx and the PMd suggests these two anatomically-connected areas negatively co-operate. These findings have implications for understanding the disruption and reorganization of the motor systems after stroke. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Age matters: The effect of onset age of video game play on task-switching abilities.

Science.gov (United States)

Hartanto, Andree; Toh, Wei Xing; Yang, Hwajin

2016-05-01

Although prior research suggests that playing video games can improve cognitive abilities, recent empirical studies cast doubt on such findings (Unsworth et al., 2015). To reconcile these inconsistent findings, we focused on the link between video games and task switching. Furthermore, we conceptualized video-game expertise as the onset age of active video-game play rather than the frequency of recent gameplay, as it captures both how long a person has played video games and whether the individual began playing during periods of high cognitive plasticity. We found that the age of active onset better predicted switch and mixing costs than did frequency of recent gameplay; specifically, players who commenced playing video games at an earlier age reaped greater benefits in terms of task switching than did those who started at a later age. Moreover, improving switch costs required a more extensive period of video-game experience than did mixing costs; this finding suggests that certain cognitive abilities benefit from different amounts of video game experience.

Wide Bandgap Extrinsic Photoconductive Switches

Energy Technology Data Exchange (ETDEWEB)

Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)

2012-01-20

Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

Electron collisions in gas switches

International Nuclear Information System (INIS)

Christophorou, L.G.

1989-01-01

Many technologies rely on the conduction/insulation properties of gaseous matter for their successful operation. Many others (e.g., pulsed power technologies) rely on the rapid change (switching or modulation) of the properties of gaseous matter from an insulator to a conductor and vice versa. Studies of electron collision processes in gases aided the development of pulsed power gas switches, and in this paper we shall briefly illustrate the kind of knowledge on electron collision processes which is needed to optimize the performance of such switching devices. To this end, we shall refer to three types of gas switches: spark gap closing, self-sustained diffuse discharge closing, and externally-sustained diffuse discharge opening. 24 refs., 15 figs., 2 tabs

Switching Adaptability in Human-Inspired Sidesteps: A Minimal Model.

Science.gov (United States)

Fujii, Keisuke; Yoshihara, Yuki; Tanabe, Hiroko; Yamamoto, Yuji

2017-01-01

Humans can adapt to abruptly changing situations by coordinating redundant components, even in bipedality. Conventional adaptability has been reproduced by various computational approaches, such as optimal control, neural oscillator, and reinforcement learning; however, the adaptability in bipedal locomotion necessary for biological and social activities, such as unpredicted direction change in chase-and-escape, is unknown due to the dynamically unstable multi-link closed-loop system. Here we propose a switching adaptation model for performing bipedal locomotion by improving autonomous distributed control, where autonomous actuators interact without central control and switch the roles for propulsion, balancing, and leg swing. Our switching mobility model achieved direction change at any time using only three actuators, although it showed higher motor costs than comparable models without direction change. Our method of evaluating such adaptation at any time should be utilized as a prerequisite for understanding universal motor control. The proposed algorithm may simply explain and predict the adaptation mechanism in human bipedality to coordinate the actuator functions within and between limbs.

Implementation of Single Phase Soft Switched PFC Converter for Plug-in-Hybrid Electric Vehicles

Directory of Open Access Journals (Sweden)

Aiswariya Sekar

2015-11-01

Full Text Available This paper presents a new soft switching boost converter with a passive snubber cell without additional active switches for battery charging systems. The proposed snubber finds its application in the front-end ac-dc converter of Plug-in Hybrid Electric Vehicle (PHEV battery chargers. The proposed auxiliary snubber circuit consists of an inductor, two capacitors and two diodes. The new converter has the advantages of continuous input current, low switching stresses, high voltage gain without extreme duty cycle, minimized charger size and charging time and fewer amounts of cost and electricity drawn from the utility at higher switching frequencies. The switch is made to turn ON by Zero Current Switching (ZCS and turn OFF by Zero Voltage Switching (ZVS. The detailed steady state analysis of the novel ac-dc Zero Current- Zero Voltage Switching (ZC-ZVS boost Power Factor Correction (PFC converter is presented with its operating principle. The experimental prototype of 20 kHz, 100 W converter verifies the theoretical analysis. The power factor of the prototype circuit reaches near unity with an efficiency of 97%, at nominal output power for a ±10% variation in the input voltage and ±20% variation in the snubber component values.

47 CFR 69.106 - Local switching.

Science.gov (United States)

2010-10-01

... foreign services that use local exchange switching facilities. (c) If end users of an interstate or... local exchange carriers shall establish rate elements for local switching as follows: (1) Price cap... use local exchange switching facilities for the provision of interstate or foreign services. The...

Blood Pressure Control in Smokers with Arterial Hypertension Who Switched to Electronic Cigarettes

Directory of Open Access Journals (Sweden)

Riccardo Polosa

2016-11-01

Full Text Available Electronic cigarettes (ECs are battery-operated devices designed to vaporise nicotine, which may help smokers with quitting or reducing their tobacco consumption. No data is available regarding the health effects of ECs use among smokers with arterial hypertension and whether regular use results in blood pressure (BP changes. We investigated long-term changes in resting BP and level of BP control in hypertensive smokers who quit or reduced substantially their tobacco consumption by switching to ECs. A medical records review of patients with hypertension was conducted to identify patients reporting regular daily use of ECs on at least two consecutive follow-up visits. Regularly smoking hypertensive patients were included as a reference group. A marked reduction in cigarette consumption was observed in ECs users (n = 43 though consumption remained unchanged in the control group (n = 46. Compared to baseline, at 12 months (follow-up visit 2 decline in cigarette consumption was associated with significant reductions in median (25th-, 75th-centile systolic BP (140 (134.5, 144 to 130 (123.5, 138.5 mmHg; p < 0.001 and diastolic BP (86 (78, 90 to 80 (74.5, 90 mmHg; p = 0.006. No significant changes were observed in the control group. As expected, decline in cigarette consumption in the ECs users was also associated with improved BP control. The study concludes that regular ECs use may aid smokers with arterial hypertension reduce or abstain from cigarette smoking, with only trivial post-cessation weight gain. This resulted in improvements in systolic and diastolic BP as well as better BP control.

Condition Number Regularized Covariance Estimation*

Science.gov (United States)

Won, Joong-Ho; Lim, Johan; Kim, Seung-Jean; Rajaratnam, Bala

2012-01-01

Estimation of high-dimensional covariance matrices is known to be a difficult problem, has many applications, and is of current interest to the larger statistics community. In many applications including so-called the “large p small n” setting, the estimate of the covariance matrix is required to be not only invertible, but also well-conditioned. Although many regularization schemes attempt to do this, none of them address the ill-conditioning problem directly. In this paper, we propose a maximum likelihood approach, with the direct goal of obtaining a well-conditioned estimator. No sparsity assumption on either the covariance matrix or its inverse are are imposed, thus making our procedure more widely applicable. We demonstrate that the proposed regularization scheme is computationally efficient, yields a type of Steinian shrinkage estimator, and has a natural Bayesian interpretation. We investigate the theoretical properties of the regularized covariance estimator comprehensively, including its regularization path, and proceed to develop an approach that adaptively determines the level of regularization that is required. Finally, we demonstrate the performance of the regularized estimator in decision-theoretic comparisons and in the financial portfolio optimization setting. The proposed approach has desirable properties, and can serve as a competitive procedure, especially when the sample size is small and when a well-conditioned estimator is required. PMID:23730197

Resistance switching memory in perovskite oxides

International Nuclear Information System (INIS)

Yan, Z.B.; Liu, J.-M.

2015-01-01

The resistance switching behavior has recently attracted great attentions for its application as resistive random access memories (RRAMs) due to a variety of advantages such as simple structure, high-density, high-speed and low-power. As a leading storage media, the transition metal perovskite oxide owns the strong correlation of electrons and the stable crystal structure, which brings out multifunctionality such as ferroelectric, multiferroic, superconductor, and colossal magnetoresistance/electroresistance effect, etc. The existence of rich electronic phases, metal–insulator transition and the nonstoichiometric oxygen in perovskite oxide provides good platforms to insight into the resistive switching mechanisms. In this review, we first introduce the general characteristics of the resistance switching effects, the operation methods and the storage media. Then, the experimental evidences of conductive filaments, the transport and switching mechanisms, and the memory performances and enhancing methods of perovskite oxide based filamentary RRAM cells have been summarized and discussed. Subsequently, the switching mechanisms and the performances of the uniform RRAM cells associating with the carrier trapping/detrapping and the ferroelectric polarization switching have been discussed. Finally, the advices and outlook for further investigating the resistance switching and enhancing the memory performances are given

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....

Manually operated coded switch

International Nuclear Information System (INIS)

Barnette, J.H.

1978-01-01

The disclosure related to a manually operated recodable coded switch in which a code may be inserted, tried and used to actuate a lever controlling an external device. After attempting a code, the switch's code wheels must be returned to their zero positions before another try is made

Morphological analysis of GeTe in inline phase change switches

Energy Technology Data Exchange (ETDEWEB)

King, Matthew R., E-mail: matthew.king2@ngc.com [Northrop Grumman Electronic Systems, Advanced Concepts and Technologies Division, 1212 Winterson Rd., Linthicum, Maryland 21090 (United States); Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); El-Hinnawy, Nabil [Northrop Grumman Electronic Systems, Advanced Concepts and Technologies Division, 1212 Winterson Rd., Linthicum, Maryland 21090 (United States); Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Salmon, Mike; Gu, Jitty [Evans Analytical Group, 628 Hutton St., Raleigh, North Carolina 27606 (United States); Wagner, Brian P.; Jones, Evan B.; Howell, Robert S.; Nichols, Doyle T.; Young, Robert M. [Northrop Grumman Electronic Systems, Advanced Concepts and Technologies Division, 1212 Winterson Rd., Linthicum, Maryland 21090 (United States); Borodulin, Pavel [Northrop Grumman Electronic Systems, Advanced Concepts and Technologies Division, 1212 Winterson Rd., Linthicum, Maryland 21090 (United States); Department of Electrical and Computer Engineering, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)

2015-09-07

Crystallization and amorphization phenomena in indirectly heated phase change material-based devices were investigated. Scanning transmission electron microscopy was utilized to explore GeTe phase transition processes in the context of the unique inline phase change switch (IPCS) architecture. A monolithically integrated thin film heating element successfully converted GeTe to ON and OFF states. Device cycling prompted the formation of an active area which sustains the majority of structural changes during pulsing. A transition region on both sides of the active area consisting of polycrystalline GeTe and small nuclei (<15 nm) in an amorphous matrix was also observed. The switching mechanism, determined by variations in pulsing parameters, was shown to be predominantly growth-driven. A preliminary model for crystallization and amorphization in IPCS devices is presented.

Morphological analysis of GeTe in inline phase change switches

International Nuclear Information System (INIS)

King, Matthew R.; El-Hinnawy, Nabil; Salmon, Mike; Gu, Jitty; Wagner, Brian P.; Jones, Evan B.; Howell, Robert S.; Nichols, Doyle T.; Young, Robert M.; Borodulin, Pavel

2015-01-01

Crystallization and amorphization phenomena in indirectly heated phase change material-based devices were investigated. Scanning transmission electron microscopy was utilized to explore GeTe phase transition processes in the context of the unique inline phase change switch (IPCS) architecture. A monolithically integrated thin film heating element successfully converted GeTe to ON and OFF states. Device cycling prompted the formation of an active area which sustains the majority of structural changes during pulsing. A transition region on both sides of the active area consisting of polycrystalline GeTe and small nuclei (<15 nm) in an amorphous matrix was also observed. The switching mechanism, determined by variations in pulsing parameters, was shown to be predominantly growth-driven. A preliminary model for crystallization and amorphization in IPCS devices is presented